WO2023004821A1 - 电解液、二次电池、电池模块、电池包和用电装置 - Google Patents

电解液、二次电池、电池模块、电池包和用电装置 Download PDF

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WO2023004821A1
WO2023004821A1 PCT/CN2021/109905 CN2021109905W WO2023004821A1 WO 2023004821 A1 WO2023004821 A1 WO 2023004821A1 CN 2021109905 W CN2021109905 W CN 2021109905W WO 2023004821 A1 WO2023004821 A1 WO 2023004821A1
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Prior art keywords
negative electrode
battery
organic solvent
compounds
methylene
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PCT/CN2021/109905
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English (en)
French (fr)
Inventor
张立美
陈培培
李丽叶
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Contemporary Amperex Technology Co Ltd
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Contemporary Amperex Technology Co Ltd
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Priority to JP2023501614A priority Critical patent/JP7653505B2/ja
Priority to PL21946250.4T priority patent/PL4160773T3/pl
Priority to CN202180073107.7A priority patent/CN116349050B/zh
Priority to EP21946250.4A priority patent/EP4160773B1/en
Priority to KR1020237001282A priority patent/KR102889485B1/ko
Priority to EP25213006.7A priority patent/EP4734215A2/en
Application filed by Contemporary Amperex Technology Co Ltd filed Critical Contemporary Amperex Technology Co Ltd
Priority to ES21946250T priority patent/ES3060465T3/es
Priority to PCT/CN2021/109905 priority patent/WO2023004821A1/zh
Publication of WO2023004821A1 publication Critical patent/WO2023004821A1/zh
Priority to US18/322,597 priority patent/US20230318042A1/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0567—Liquid materials characterised by the additives
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0568—Liquid materials characterised by the solutes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0569—Liquid materials characterised by the solvents
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • H01M2300/0028—Organic electrolyte characterised by the solvent
    • H01M2300/0037—Mixture of solvents
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the application belongs to the technical field of secondary batteries, and specifically relates to an electrolyte, a secondary battery, a battery module, a battery pack and an electrical device.
  • the purpose of this application is to provide an electrolyte, a secondary battery, a battery module, a battery pack, and an electrical device, aiming to make the battery have a good fast charge while having a long cycle life and storage life performance.
  • the first aspect of the present application provides an electrolytic solution, the electrolytic solution includes an organic solvent and additives.
  • the organic solvent includes the first organic solvent shown in Formula 1.
  • R 1 and R 2 are each independently one of C1-C3 alkyl and C1-C3 haloalkyl.
  • the additives include the first additive, and the first additive is selected from one or more of the compounds shown in formula 2A and formula 2B.
  • R 21 , R 22 , R 23 , and R 24 are independently is one of a single bond and a methylene group
  • R 31 , R 32 , R 33 , and R 34 are each independently a single bond or one of a methylene group
  • R 4 is a single bond, - One of O-, C1-C3 alkylene, C1-C3 haloalkylene, and C1-C3 oxaalkylene.
  • the combined use of the first additive and the first organic solvent can ensure that the battery has good cycle performance and storage performance while giving full play to the effect of the first organic solvent on improving the conductivity of the electrolyte.
  • R 1 and R 2 are each independently one of methyl, ethyl, propyl, fluoromethyl, fluoroethyl, and fluoropropyl. Selecting a suitable first organic solvent can keep the viscosity of the electrolyte within an appropriate range, so the electrolyte has higher conductivity and the battery has better fast charging performance.
  • the first organic solvent is selected from one or more of the following compounds:
  • the first organic solvent is selected from one or both of the following compounds:
  • Compound 1-1 and compound 1-2 have lower viscosity, and the effect on improving the conductivity of the electrolyte is more obvious.
  • R 21 , R 22 , R 23 , and R 24 are each independently one of a single bond and a methylene group.
  • R 21 , R 22 , R 23 and R 24 are not single bonds at the same time.
  • R 21 and R 22 are methylene
  • R 23 and R 24 are methylene
  • R 31 , R 32 , R 33 , and R 34 are each independently a single bond or a methylene group, and R 31 , R 32 , R 33 , R 34 are not single bonds at the same time.
  • R 4 is a single bond, -O-, methylene, ethylene, propylene, fluoromethylene, fluoroethylene, fluoroethylene One of propyl, methyleneoxy, ethyleneoxy, and propyleneoxy.
  • R 4 is one of a single bond, methylene, ethylene, and propylene.
  • the first additive whose substituent is in the above-mentioned range can form a dense and stable interfacial film on the surface of the negative electrode active material, and block the direct contact between the first organic solvent and the negative electrode active material, so it can further improve the flow of active ions in the positive and negative electrode sheets.
  • the reversibility of de-intercalation improves the discharge capacity and cycle performance of the battery.
  • R 4 when R 4 is a single bond, one or both of R 31 and R 32 are methylene, and the rest are single bonds.
  • R 4 when R 4 is a single bond, one or both of R 33 and R 34 are methylene, and the rest are single bonds.
  • R 4 when R 4 is a single bond, one of R 31 and R 32 is methylene, one of R 33 and R 34 is methylene, and the rest are single bonds.
  • both R 31 and R 32 are methylene, one of R 33 and R 34 is methylene, and the rest are single bonds.
  • both R 33 and R 34 are methylene, one of R 31 and R 32 is methylene, and the rest are single bonds.
  • R 31 , R 32 , R 33 and R 34 are all methylene.
  • the first additive is selected from one or more of the following compounds:
  • the above-mentioned first additive can form a stable and long-lasting interfacial film on the surface of the negative electrode active material, further improving the cycle performance and storage performance of the battery.
  • the first additive is selected from one or more of the following compounds:
  • the mass percentage of the first organic solvent is w1, and the range of w1 is 20%-80%.
  • w1 ranges from 30% to 70%.
  • the mass percentage of the first organic solvent is controlled within an appropriate range, which can make the battery have good cycle performance and storage performance while improving the fast charging performance of the battery.
  • the mass percentage of the first additive is w2, and the range of w2 is 0.1%-10%.
  • w2 ranges from 0.5% to 5%.
  • the mass percentage of the first additive is controlled in an appropriate range, so that the battery can have good fast charging performance, cycle performance and storage performance.
  • the additive also includes a second additive, the second additive contains a cyclic carbonate compound, a halogen-substituted cyclic carbonate compound, a sulfate compound, a sulfite compound containing an unsaturated bond , sultone compound, disulfonic acid compound, nitrile compound, aromatic compound, isocyanate compound, phosphazene compound, cyclic anhydride compound, phosphite compound, phosphate compound, borate compound, carboxylate compound one or several.
  • These second additives can form a denser and more stable interfacial film on the surface of the positive electrode active material and/or the negative electrode active material, which helps to further improve the cycle performance and storage performance of the battery.
  • the second additive includes one or both of the following compounds:
  • the cycle performance and storage performance of the battery can be further enhanced.
  • the mass percentage of the second additive is w3, and the range of w3 is ⁇ 10%.
  • the range of w3 is ⁇ 5%.
  • the mass percentage of the second additive is controlled within an appropriate range, which can further enhance the cycle performance of the battery.
  • the organic solvent further includes a second organic solvent, and the second organic solvent includes one or more of cyclic carbonate compounds and chain carbonate compounds.
  • the second organic solvent includes a cyclic carbonate compound, or a combination of a cyclic carbonate compound and a chain carbonate compound.
  • the organic solvent also includes the above-mentioned second organic solvent, which can make the battery containing the electrolyte have good fast charging performance.
  • the second organic solvent includes ethylene carbonate, propylene carbonate, 1,2-butenyl carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, dipropylene carbonate One or more of esters, methyl propyl carbonate, ethylene propyl carbonate.
  • the electrolyte containing the second organic solvent composed of the above compounds can make the battery containing the electrolyte have better fast charging performance.
  • the mass percentage of the cyclic carbonate compound is w4, and the range of w4 is 20%-80%.
  • w4 ranges from 20% to 50%.
  • the high dielectric constant of cyclic carbonate compounds is beneficial to the dissociation of lithium salts.
  • the mass percentage of the cyclic carbonate compound is controlled in an appropriate range, so that the battery containing the electrolyte has more excellent fast charging performance.
  • the electrolyte solution further includes a lithium salt
  • the lithium salt includes LiN(C x F 2x+1 SO 2 )(C y F 2y+1 SO 2 ), LiPF 6 , LiBF 4 , LiBOB, One or more of LiDFOB, LiPO 2 F 2 , LiDFOP, LiTFOP, LiAsF 6 , Li(FSO 2 ) 2 N, LiCF 3 SO 3 and LiClO 4 , where x and y are positive integers.
  • the electrolyte includes the above-mentioned lithium salt, which can help form a uniform, dense, and low-impedance interfacial film on the surface of the negative electrode active material of the battery, and effectively improve the fast charging performance and cycle performance of the battery.
  • the conductivity of the electrolyte satisfies ⁇ 12 mS/cm.
  • the conductivity of the electrolyte satisfies ⁇ 13mS/cm.
  • the conductivity of the electrolyte is controlled within an appropriate range, enabling the battery to have good fast charging performance, cycle performance, storage performance and safety performance.
  • the conductivity of the electrolyte is 12mS/cm-24mS/cm.
  • the conductivity of the electrolyte is 13mS/cm-20mS/cm.
  • the second aspect of the present application provides a secondary battery, which includes the electrolyte solution of the first aspect of the present application.
  • the secondary battery of the present application includes the electrolyte solution of the first aspect of the present application, and the secondary battery has excellent cycle performance and storage performance while having good fast charging performance.
  • the secondary battery includes a negative electrode sheet
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector and including a negative electrode active material.
  • the ratio H/Dv50 of the thickness H of the single-sided negative electrode film layer to the volume average particle diameter Dv50 of the negative electrode active material satisfies ⁇ 3.
  • H/Dv50 satisfies ⁇ 3.5.
  • the range of H/Dv50 satisfies 4 ⁇ H/Dv50 ⁇ 9.
  • the value of H/Dv50 is within a suitable range, which can further improve the fast charging performance of the secondary battery on the basis of ensuring that the secondary battery has a high volumetric energy density.
  • the thickness H of the single-sided negative electrode film layer satisfies ⁇ 60 ⁇ m.
  • the thickness H of the single-sided negative electrode film layer satisfies ⁇ 65 ⁇ m.
  • the thickness H of the single-sided negative electrode film layer is in an appropriate range, which can further increase the energy density of the battery.
  • the volume average particle diameter Dv50 of the negative electrode active material satisfies ⁇ 18 ⁇ m.
  • the volume average particle diameter Dv50 of the negative electrode active material satisfies 14 ⁇ m ⁇ Dv50 ⁇ 18 ⁇ m.
  • the volume average particle size Dv50 of the negative electrode active material is in an appropriate range, which can not only increase the diffusion coefficient of active ions, but also reduce the contact area between the negative electrode film layer and the electrolyte, and the battery can have good fast charging performance and cycle performance at the same time and storage performance.
  • the negative electrode film layer has a compacted density of 1.4 g/cm 3 to 1.85 g/cm 3 .
  • the compacted density of the negative electrode film layer is 1.6g/cm 3 -1.8g/cm 3 .
  • the compaction density of the negative electrode film layer is in an appropriate range, so that the battery can have both high energy density and good fast charging performance.
  • the secondary battery includes a positive electrode sheet, and the positive electrode sheet includes a positive electrode active material, and the positive electrode active material includes lithium transition metal oxides, lithium-containing phosphates with an olivine structure, and their respective modified compounds. one or more of.
  • the lithium-containing phosphate of olivine structure includes lithium iron phosphate, a composite material of lithium iron phosphate and carbon, lithium manganese phosphate, a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, manganese phosphate One or more of the composite materials of iron lithium and carbon and their modified compounds.
  • the use of these positive electrode active materials in the positive electrode film layer can improve the rate performance and energy density of the battery while improving the battery cycle performance and storage performance.
  • a third aspect of the present application provides a battery module, which includes the secondary battery of the second aspect of the present application.
  • a fourth aspect of the present application provides a battery pack, which includes one of the secondary battery of the second aspect of the present application and the battery module of the third aspect.
  • the fifth aspect of the present application provides an electric device, which includes at least one of the secondary battery of the second aspect of the present application, the battery module of the third aspect, and the battery pack of the fourth aspect.
  • the battery module, battery pack and electric device of the present application include the secondary battery provided by the present application, and thus have at least the same advantages as the secondary battery.
  • FIG. 1 is a schematic diagram of an embodiment of a secondary battery of the present application.
  • FIG. 2 is an exploded schematic diagram of an embodiment of the secondary battery of the present application.
  • Fig. 3 is a schematic diagram of an embodiment of the battery module of the present application.
  • Fig. 4 is a schematic diagram of an embodiment of the battery pack of the present application.
  • FIG. 5 is an exploded view of FIG. 4 .
  • FIG. 6 is a schematic diagram of an embodiment of an electrical device in which a secondary battery is used as a power source of the present application.
  • any lower limit can be combined with any upper limit to form an unexpressed range; and any lower limit can be combined with any other lower limit to form an unexpressed range, just as any upper limit can be combined with any other upper limit to form an unexpressed range.
  • every point or individual value between the endpoints of a range is included within that range, although not expressly stated herein. Thus, each point or individual value may serve as its own lower or upper limit in combination with any other point or individual value or with other lower or upper limits to form a range not expressly recited.
  • the term "or” is inclusive.
  • the phrase “A or B” means “A, B, or both A and B.” More specifically, the condition “A or B” is satisfied by either of the following: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists) ; or both A and B are true (or exist).
  • Secondary batteries also known as rechargeable batteries or accumulators, refer to batteries that can be activated by charging the active materials and continue to be used after the battery is discharged.
  • a secondary battery typically includes a positive pole piece, a negative pole piece, a separator, and an electrolyte.
  • active ions such as lithium ions
  • the separator is arranged between the positive pole piece and the negative pole piece, which mainly plays a role in preventing the short circuit of the positive and negative poles, and at the same time allows active ions to pass through.
  • the electrolyte is between the positive pole piece and the negative pole piece, and mainly plays the role of conducting active ions.
  • the secondary battery includes the electrolyte, which is the bridge for active ions in the secondary battery, and plays the role of transporting active ions between the positive and negative electrodes in the battery. Performance etc. all play a crucial role.
  • the carboxylate is not compatible with the negative electrode, and the ⁇ -H on the carboxylate is easy to react with the active lithium obtained by reducing the negative electrode, resulting in the loss of active lithium and affecting the cycle performance and storage performance of the battery, especially in high temperature environments. The deterioration in performance and storage performance is more pronounced.
  • carboxylate esters have poor oxidation resistance and are prone to oxidative decomposition when stored at a high state of charge, further affecting the storage performance of the battery.
  • carboxylic acid esters have poor oxidation resistance and are prone to oxidative decomposition when stored at a high state of charge, further affecting the storage performance of the battery.
  • the prior art reports adding cyclic sulfuric acid esters to the electrolyte, and cyclic sulfuric acid esters can form interfacial films on the surfaces of positive active materials and negative active materials. Block the direct contact between the positive electrode active material, the negative electrode active material and the electrolyte, and inhibit the continuous reaction between the negative electrode and the carboxylate in the electrolyte.
  • the inventors further conducted a lot of research and skillfully added the first additive represented by formula 2A and/or formula 2B to the electrolyte solution containing carboxylic acid ester, breaking the bottleneck mentioned above.
  • the electrolytic solution of the present application can ensure that the battery has good cycle performance and storage performance while giving full play to the effect of carboxylate on the conductivity of the electrolyte and the rapid charging performance of the battery, especially to ensure that the battery still has good performance in high temperature environments. Cycle performance and storage performance.
  • the electrolyte solution of the present application includes an organic solvent and an additive, wherein the organic solvent includes the first organic solvent shown in Formula 1, the additive includes a first additive, and the first additive is selected from Formula 2A, Formula One or more of the compounds shown in 2B.
  • the first additive is selected from one or more of the compounds shown in Formula 2A; in some embodiments, the first additive is selected from one or more of the compounds shown in Formula 2B One or more; In some embodiments, the first additive includes both the compound shown in Formula 2A and the compound shown in Formula 2B.
  • R 1 and R 2 are independently one of C1-C3 alkyl and C1-C3 haloalkyl, and R 1 and R 2 may be the same or different.
  • Alkyl and haloalkyl may be linear or branched.
  • the number of halogen atoms in the haloalkyl group may be one or multiple; when there are multiple halogen atoms in the haloalkyl group, these halogen atoms may be the same or different.
  • R 21 , R 22 , R 23 , and R 24 are each independently one of a single bond and a methylene group (—CH 2 —). R 21 , R 22 , R 23 , and R 24 may be the same or different.
  • R 31 , R 32 , R 33 , and R 34 are each independently a single bond or a methylene group, and R 4 is a single bond, -O-, C1 ⁇ C3 alkylene, C1 ⁇ C3 One of C3 haloalkylene and C1-C3 oxaalkylene.
  • the alkylene group, haloalkylene group, and oxaalkylene group may have a straight-chain structure or a branched-chain structure.
  • the number of halogen atoms in the haloalkylene group may be one or more; when there are multiple halogen atoms in the haloalkylene group, these halogen atoms may be the same or different.
  • the number of oxygen atoms in the oxaalkylene group may be one or more.
  • R 31 , R 32 , R 33 , and R 34 are single bonds, it means that R 4 is directly bonded to -O- adjacent to R 31 , R 32 , R 33 , and R 34 via a single bond.
  • R 31 , R 32 , R 33 , and R 34 may be the same or different,
  • the first additive is added to the electrolyte solution of the present application, which has a higher reduction potential, can accept electrons from the negative electrode during charging and self-reduce, and forms a dense and stable layer on the surface of the negative electrode active material in preference to the first organic solvent.
  • the sulfur-containing organic interface film inhibits the reaction between the first organic solvent and the active lithium obtained by reduction at the negative electrode.
  • the first additive has high thermal stability, does not generate gas during the formation of the sulfur-containing organic interfacial film, and does not affect the cycle performance and storage performance of the battery, especially the cycle performance and storage performance in high temperature environments.
  • the first additive can also form an interfacial film on the surface of the positive electrode active material prior to the first organic solvent, and inhibit the oxidative decomposition of the first organic solvent on the positive electrode; the first additive can also coordinate with the transition metal on the surface of the positive electrode active material to form a complex , making the interfacial film formed on the surface of the positive electrode active material denser and more stable, effectively preventing direct contact between the organic solvent (especially the first organic solvent) and the positive electrode active material.
  • the combined use of the first additive and the first organic solvent can ensure that the battery has good cycle performance and storage performance while giving full play to the effect of the first organic solvent on improving the conductivity of the electrolyte. Therefore, the electrolyte of the present application can make the battery have both excellent fast charging performance and good cycle performance and storage performance.
  • the inventor discovered for the first time during the research process that the first additive added to the electrolyte can inhibit the reaction between the first organic solvent and the negative electrode and ensure that the battery has good cycle performance and storage performance.
  • the first additive added to the electrolyte can inhibit the reaction between the first organic solvent and the negative electrode and ensure that the battery has good cycle performance and storage performance.
  • R 1 and R 2 can be independently one of methyl, ethyl, propyl, fluoromethyl, fluoroethyl, and fluoropropyl.
  • R 1 and R 2 may be the same or different.
  • the number of fluorine atoms may be one or more.
  • the first organic solvent can be selected from one or more of the following compounds:
  • the electrolyte contains one or more of the above compounds, the electrolyte has a moderate viscosity and higher electrical conductivity, thereby significantly improving the fast charging performance of the battery.
  • the first organic solvent can be selected from one or both of the following compounds:
  • compound 1-1 and compound 1-2 have lower viscosity, therefore, they have a more obvious effect on improving the conductivity of the electrolyte, thereby enabling the battery to have better fast charging performance.
  • the mass percentage of the first organic solvent is w1, and the range of w1 may be 20%-80%.
  • w1 may range from 25% to 80%, 25% to 75%, 30% to 70%, 30% to 60%, 35% to 65%, 35% to 60%, 40% to 60%, or 50% to 60%.
  • the inventor controls the mass percentage of the first organic solvent within an appropriate range, which can improve the rapid charging of the battery. At the same time, the battery has good cycle performance and storage performance.
  • R 21 , R 22 , R 23 , and R 24 are not single bonds at the same time.
  • one or both of R 21 and R 22 are methylene, and one or both of R 23 and R 24 are methylene.
  • R 21 and R 23 are methylene, and R 22 and R 24 are single bonds.
  • R 21 and R 23 are methylene, one of R 22 and R 24 is methylene, and the rest are single bonds.
  • R 21 , R 22 , R 23 , and R 24 are all methylene.
  • R 31 , R 32 , R 33 , and R 34 can each independently be a single bond or a methylene group, and R 31 , R 32 , R 33 , and R 34 Not single key at the same time.
  • R 31 , R 32 , R 33 , R 34 are methylene.
  • R in Formula 2B, R can be a single bond, O-, methylene, ethylene, propylene, fluoromethylene, fluoroethylene, fluoropropylene , methyleneoxy, ethyleneoxy, propyleneoxy in one.
  • R 4 is one of a single bond, methylene, ethylene, and propylene. These substituents may be linear or branched. The number of fluorine atoms may be one or more.
  • the first additive can form a dense and stable interfacial film on the surface of the positive electrode active material and the negative electrode active material, blocking the direct contact of the first organic solvent with the positive electrode active material and the negative electrode active material, reducing the activity.
  • the loss of lithium can further improve the reversibility of active ions between the positive and negative electrodes, and improve the discharge capacity and cycle performance of the battery.
  • R 4 when R 4 is a single bond, one or both of R 31 and R 32 are methylene, and the rest are single bonds.
  • R 4 when R 4 is a single bond, one or both of R 33 and R 34 are methylene, and the rest are single bonds.
  • R 4 when R 4 is a single bond, one of R 31 and R 32 is methylene, one of R 33 and R 34 is methylene, and the rest are single bonds.
  • both R 31 and R 32 are methylene, one of R 33 and R 34 is methylene, and the rest are single bonds.
  • both R 33 and R 34 are methylene, one of R 31 and R 32 is methylene, and the rest are single bonds.
  • R 31 , R 32 , R 33 and R 34 are all methylene.
  • the first additive can be selected from one or more of the following compounds:
  • the inventors have found that using one or more of the above compounds as the first additive can form a more stable and durable interface film on the surface of the positive electrode active material and the negative electrode active material; even after a long period of charge and discharge, the interface film remains stable. It can effectively prevent the direct contact between the organic solvent (especially the first organic solvent) and the positive electrode active material and the negative electrode active material, thus further improving the cycle performance and storage performance of the battery.
  • the organic solvent especially the first organic solvent
  • the first additive is selected from one or more of the following compounds:
  • the first additive is selected from one or both of the following compounds:
  • the mass percentage of the first additive is w2, and w2 may be ⁇ 10%.
  • w2 may range from 0.05% to 10%, 0.1% to 10%, 0.5% to 10%, 0.5% to 8%, 0.5% to 5%, 1% to 5%, or 2% to 5%.
  • the mass percentage of the first additive is within an appropriate range, the synergistic effect of the first additive and the first organic solvent can be fully exerted.
  • the inventor selected the mass percentage range of the first additive, so that the battery has good fast charging performance, cycle performance and storage performance.
  • the additive may also include a second additive.
  • the second additive may include a cyclic carbonate compound containing an unsaturated bond, a halogen-substituted cyclic carbonate compound, a sulfate compound, a sulfite compound, a sultone compound, a disulfonic acid compound, a nitrile compound, One or more of aromatic compounds, isocyanate compounds, phosphazene compounds, cyclic acid anhydride compounds, phosphite compounds, phosphate compounds, borate compounds, and carboxylate compounds.
  • These second additives can form a denser and more stable interfacial film on the surface of the positive electrode active material and/or the negative electrode active material, which helps to further improve the cycle performance and storage performance of the battery.
  • the second additive may include one or both of the following compounds:
  • the cycle performance and storage performance of the battery can be further enhanced.
  • the mass percentage of the second additive is w3, and the range of w3 may be ⁇ 10%.
  • w3 may range from ⁇ 9%, ⁇ 8%, ⁇ 7%, ⁇ 6%, ⁇ 5%, ⁇ 4%, ⁇ 3%, ⁇ 2%, or ⁇ 1%.
  • the mass percentage w3 of the second additive may be 1%-10%, 1%-8%, 1%-7%, 1%-5%, 1% to 4%, 1% to 3%, or 1% to 2%.
  • the cycle performance and storage performance of the battery can be further enhanced.
  • the organic solvent may also include a second organic solvent, and the second organic solvent may include one or more of cyclic carbonate compounds and chain carbonate compounds.
  • the second organic solvent may include a cyclic carbonate compound, or a combination of a cyclic carbonate compound and a chain carbonate compound.
  • the second organic solvent may include ethylene carbonate (EC), propylene carbonate (PC), 1,2-butenyl carbonate (BC), dimethyl carbonate (DMC), methyl carbonate
  • EMC Ethyl Carbonate
  • DEC Diethyl Carbonate
  • DPC Dipropyl Carbonate
  • MPC Methyl Propyl Carbonate
  • EPC Ethyl Propyl Carbonate
  • the mass percentage of the second organic solvent may range from 20% to 80%.
  • the mass percent of the second organic solvent ranges from 20% to 75%, 25% to 75%, 30% to 70%, 40% to 70%, 35% to 65%, 40% to 65% %, 40% to 60%, or 40% to 50%.
  • the mass percentage of the cyclic carbonate compound is w4, and the range of w4 may be 20%-80%.
  • w4 may range from 20% to 50%, 25% to 50%, 25% to 45%, 25% to 40%, 25% to 35%, 30% to 50%, 30% to 45%, or 30% to 40%.
  • the high dielectric constant of cyclic carbonate compounds is beneficial to the dissociation of lithium salts.
  • the mass percentage of the cyclic carbonate compound is controlled within an appropriate range, the battery containing the electrolyte can have more excellent fast charging performance.
  • the range of the mass percentage of the chain carbonate compound can be 0% to 50%, 0% to 40%, 0% to 30%, 0% to 25%, 0%-20%, 10%-50%, 10%-40%, 10%-30%, or 10%-20%.
  • the electrolyte also includes a lithium salt.
  • the present application has no specific limitation on the type of lithium salt, which can be selected according to actual needs.
  • the lithium salt may include LiN(C x F 2x+1 SO 2 )(C y F 2y+1 SO 2 ), LiPF 6 , LiBF 4 , LiBOB, LiDFOB, LiPO 2 F 2 , LiDFOP, LiTFOP, One or more of LiAsF 6 , Li(FSO 2 ) 2 N, LiCF 3 SO 3 and LiClO 4 , where x and y are positive integers.
  • the electrolyte solution includes the above lithium salt, it can help to form a uniform, dense, and low-impedance interfacial film on the surface of the negative electrode active material, effectively improving the fast charging performance and cycle performance of the battery.
  • the conductivity of the electrolyte can satisfy ⁇ 12 mS/cm.
  • the conductivity of the electrolyte can satisfy ⁇ 12mS/cm, ⁇ 13mS/cm, ⁇ 14mS/cm, ⁇ 15mS/cm, ⁇ 16mS/cm, ⁇ 17mS/cm, ⁇ 18mS/cm, ⁇ 19mS/cm , or ⁇ 20mS/cm.
  • the battery can have good fast charging performance, cycle performance, storage performance and safety performance.
  • the conductivity of the electrolyte may be 12mS/cm ⁇ 24mS/cm.
  • the conductivity of the electrolyte can be 12mS/cm ⁇ 23mS/cm, 12mS/cm ⁇ 22mS/cm, 12mS/cm ⁇ 21mS/cm, 12mS/cm ⁇ 20mS/cm, or 13mS/cm ⁇ 20mS/cm. cm.
  • the secondary battery includes a negative electrode sheet.
  • the negative electrode sheet generally includes a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector and including negative electrode active materials.
  • the ratio H/Dv50 of the thickness H of the single-sided negative electrode film layer to the volume average particle diameter Dv50 of the negative electrode active material can be used to characterize the number of longitudinal particles in a unit negative electrode film layer.
  • the inventors have found that the more the number of longitudinal particles of the unit negative film layer containing the negative active material, the higher the diffusion coefficient of the active ions, and the better the fast charging performance of the battery; however, the longitudinal particles of the unit negative film layer containing the negative active material The larger the number, the larger the contact area between the negative electrode film layer and the electrolyte, and the increased side reactions of the electrolyte on the surface of the negative electrode active material particles, which will affect the cycle performance and storage performance of the battery to a certain extent. Conversely, the fewer the number of longitudinal particles per unit negative electrode film layer containing the negative electrode active material, the worse the fast charging performance of the battery, and the improved cycle performance and storage performance of the battery.
  • the inventor has conducted a lot of research and selected a suitable range of H/Dv50.
  • the ratio H/Dv50 of the thickness H of the negative electrode film layer on one side to the volume average particle diameter Dv50 of the negative electrode active material satisfies ⁇ 3.
  • H/Dv50 satisfies ⁇ 4, ⁇ 5, ⁇ 6, ⁇ 7, ⁇ 8, or ⁇ 9.
  • the value of H/Dv50 is within a suitable range, which can further improve the fast charging performance of the secondary battery on the basis of ensuring that the secondary battery has a high volumetric energy density.
  • the ratio H/Dv50 of the thickness H of the single-sided negative electrode film layer to the volume average particle diameter Dv50 of the negative electrode active material can satisfy 4 ⁇ H/Dv50 ⁇ 9. Limit the ratio H/Dv50 of the thickness H of the single-sided negative electrode film layer to the volume average particle size Dv50 of the negative electrode active material within an appropriate range, and then match the electrolyte of the application to obtain excellent fast charging performance and long service life. and high energy density secondary batteries.
  • the thickness H of the single-sided negative electrode film layer can satisfy ⁇ 60 ⁇ m.
  • the thickness of the single-sided negative electrode film layer can satisfy ⁇ 65 ⁇ m. More specifically, the thickness H of the single-sided negative electrode film layer can satisfy ⁇ 70 ⁇ m.
  • the thickness H of the single-sided negative electrode film layer is controlled in an appropriate range, which can further improve the energy density of the battery.
  • the volume average particle diameter Dv50 of the negative electrode active material can satisfy ⁇ 18 ⁇ m.
  • the volume average particle diameter Dv50 of the negative electrode active material may satisfy 14 ⁇ m ⁇ Dv50 ⁇ 18 ⁇ m.
  • the volume average particle diameter Dv50 of negative electrode active material is smaller, and the diffusion coefficient of active ion is higher; But, the volume average particle diameter Dv50 of negative electrode active material should not be too small, This will increase the contact area between the negative electrode film layer and the electrolyte, thereby affecting the cycle performance and storage performance of the battery.
  • the volume average particle size Dv50 of the negative electrode active material is in an appropriate range, which can not only improve the diffusion coefficient of active ions, but also reduce the contact area between the negative electrode film layer and the electrolyte, so the battery can simultaneously have good fast charging performance, Cycle performance and storage performance.
  • the negative electrode film layer has a compacted density of 1.4 g/cm 3 to 1.85 g/cm 3 .
  • the compacted density of the negative electrode film layer is 1.6g/cm 3 -1.8g/cm 3 .
  • the compaction density of the negative electrode film layer is controlled within an appropriate range, so that the negative electrode active material particles in the negative electrode film layer can be in close contact, and the content of the negative electrode active material per unit volume can be increased, thereby increasing the energy density of the battery.
  • the type of negative electrode active material is not specifically limited, and negative electrode active materials known in the art for secondary batteries can be used.
  • the negative electrode active material may include one or more of graphite, soft carbon, hard carbon, mesocarbon microspheres, carbon fibers, carbon nanotubes, silicon-based materials, tin-based materials, and lithium titanate.
  • the silicon-based material may include one or more of elemental silicon, silicon oxide, silicon-carbon composite, silicon-nitrogen composite, and silicon alloy materials.
  • the tin-based material may include one or more of simple tin, tin oxide, and tin alloy materials.
  • the present application is not limited to these materials, and other conventionally known materials that can be used as negative electrode active materials for secondary batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.
  • the negative electrode film layer generally includes negative electrode active materials, optional binders, optional conductive agents and other optional additives.
  • the negative electrode film layer is usually formed by coating the negative electrode slurry on the negative electrode current collector, drying and cold pressing.
  • the negative electrode slurry coating is usually formed by dispersing the negative electrode active material, optional conductive agent, optional binder, and other optional additives in a solvent and stirring them evenly.
  • the solvent may be N-methylpyrrolidone (NMP) or deionized water, but not limited thereto.
  • NMP N-methylpyrrolidone
  • the type and content of the conductive agent and the binder are not specifically limited, and can be selected according to actual needs.
  • the conductive agent may include one or more of superconducting carbon, carbon black (such as acetylene black, ketjen black, etc.), carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
  • the binder may include styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, water-based acrylic resin (for example, polyacrylic acid PAA, polymethacrylic acid PMAA, polyacrylate sodium PAAS), polyacrylamide ( One or more of PAM), polyvinyl alcohol (PVA), sodium alginate (SA) and carboxymethyl chitosan (CMCS).
  • SBR styrene-butadiene rubber
  • SR-1B water-soluble unsaturated resin
  • acrylic resin for example, polyacrylic acid PAA, polymethacrylic acid PMAA, polyacrylate sodium PAAS
  • PAM polyacrylamide
  • PVA polyvinyl alcohol
  • SA sodium alginate
  • CMCS carboxymethyl chito
  • the negative electrode film layer can be arranged on one side of the negative electrode collector, or can be arranged on both sides of the negative electrode collector.
  • the negative electrode current collector has two opposite sides in its thickness direction, and the negative electrode film layer is disposed on any one or both sides of the negative electrode current collector.
  • the type of negative electrode current collector is not specifically limited, and can be selected according to actual needs.
  • the negative electrode current collector may be a metal foil or a composite current collector.
  • the metal foil copper foil may be used for the negative electrode current collector.
  • the composite current collector may include a polymer material base and a metal material layer formed on at least one surface of the polymer material base.
  • the metal material may be selected from one or more of copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy.
  • the polymer material base layer can be selected from polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), poly Ethylene (PE), etc.
  • the parameters of the negative electrode film layer (such as thickness, compaction density, etc.) given in this application all refer to the parameters of the negative electrode film layer on one side of the negative electrode current collector.
  • the negative electrode film layer is arranged on both sides of the negative electrode current collector, if the parameters of the negative electrode film layer on any side meet the requirements of this application, it is deemed to fall within the scope of protection of this application.
  • the negative electrode film thickness, compaction density and other ranges mentioned in this application all refer to the parameters of the negative electrode film layer used for assembling the battery after being compacted by cold pressing.
  • the negative electrode sheet does not exclude other additional functional layers other than the negative electrode film layer.
  • the negative electrode sheet described in the present application may further include a conductive primer layer (for example, composed of a conductive agent and a binder) disposed between the negative electrode current collector and the negative electrode film layer.
  • the negative electrode sheet described in the present application further includes a protective layer covering the surface of the negative electrode film layer.
  • the volume average particle diameter Dv50 of the negative electrode active material is the particle diameter corresponding to when the cumulative volume distribution percentage of the negative electrode active material reaches 50%, which can be measured by laser diffraction particle size analysis.
  • a laser particle size analyzer such as Malvern Master Size 3000
  • the thickness of the negative electrode film layer is a well-known meaning in the art, and can be tested by methods known in the art, such as using a micrometer (such as Mitutoyo293-100 type, with an accuracy of 0.1 ⁇ m) for testing.
  • a micrometer such as Mitutoyo293-100 type, with an accuracy of 0.1 ⁇ m
  • the compacted density of the negative electrode film layer is a well-known meaning in the art, and can be tested by methods known in the art.
  • the compacted density of the negative electrode film layer areal density of the negative electrode film layer/thickness of the negative electrode film layer.
  • the areal density of the negative electrode film layer is a well-known meaning in the art, and can be tested by methods known in the art.
  • the sample may be sampled according to the following steps (1) to (3).
  • step (2) Bake the dried negative electrode sheet in step (1) at a certain temperature and time (for example, 400° C., 2 h), and select an area in the baked negative electrode sheet to sample the negative electrode active material ( Blade scraping powder sampling can be selected).
  • the negative electrode active material collected in step (2) is sieved (for example, sieved with a 200-mesh sieve), and finally a sample that can be used to test the parameters of each negative electrode active material mentioned above in this application is obtained.
  • the positive electrode sheet includes a positive electrode collector and a positive electrode film layer disposed on at least one surface of the positive electrode collector and including a positive electrode active material.
  • the positive electrode current collector has two opposite surfaces in its thickness direction, and the positive electrode film layer is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.
  • the positive electrode active material may include one or more of lithium transition metal oxides, olivine-structured lithium-containing phosphates and their respective modified compounds.
  • the modification compounds of the above-mentioned positive electrode active materials may be modified by doping, surface coating, or surface coating while doping.
  • the lithium transition metal oxide may include lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, One or more of lithium nickel cobalt aluminum oxide and its modified compounds.
  • the lithium-containing phosphate of olivine structure may include lithium iron phosphate, a composite material of lithium iron phosphate and carbon, lithium manganese phosphate, a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, lithium iron manganese phosphate and carbon One or more of the composite materials and their modified compounds. These positive electrode active materials may be used alone or in combination of two or more.
  • the positive electrode active material may include one or more of olivine-structured lithium-containing phosphate and modified compounds thereof. In other embodiments, the positive electrode active material may be one or more of olivine-structured lithium-containing phosphate and modified compounds thereof.
  • the use of these positive electrode active materials in the positive electrode film layer can improve the rate performance of the battery while improving the cycle performance and storage performance of the battery.
  • the operating voltage of batteries using these positive electrode active materials is not high, generally ⁇ 4.3V. Within this voltage range, the first organic solvent and the first additive have a better effect, so the cycle performance and storage performance of the battery can be further improved.
  • the positive electrode film layer generally includes a positive electrode active material, an optional binder, and an optional conductive agent.
  • the positive electrode film layer is usually formed by coating the positive electrode slurry on the positive electrode current collector, drying and cold pressing.
  • the positive electrode slurry is usually formed by dispersing the positive electrode active material, an optional conductive agent, an optional binder and any other components in a solvent and stirring them uniformly.
  • the solvent may be N-methylpyrrolidone (NMP), but is not limited thereto.
  • NMP N-methylpyrrolidone
  • the type and content of the conductive agent and the binder are not specifically limited, and can be selected according to actual needs.
  • the binder may include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene One or more of ethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resin.
  • the conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
  • the positive electrode current collector may be a metal foil or a composite current collector.
  • the metal foil aluminum foil may be used for the positive electrode current collector.
  • the composite current collector may include a polymer material base and a metal material layer formed on at least one surface of the polymer material base.
  • the metal material may be selected from one or more of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy.
  • the polymer material base layer may be selected from polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene and the like.
  • the secondary battery of the present application further includes a separator.
  • the separator is arranged between the positive pole piece and the negative pole piece to play the role of isolation.
  • the type of the isolation membrane is not specifically limited, and any known porous structure isolation membrane with good chemical stability and mechanical stability can be selected.
  • the material of the isolation film may be selected from one or more of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride, but is not limited to these.
  • the isolation film can be a single-layer film or a multi-layer composite film. When the separator is a multilayer composite film, the materials of each layer are the same or different.
  • a ceramic coating or a metal oxide coating may also be provided on the isolation film.
  • the positive pole piece, the negative pole piece and the separator can be made into an electrode assembly through a winding process or a lamination process.
  • the secondary battery may include an outer package.
  • the outer package can be used to package the above-mentioned electrode assembly and electrolyte.
  • the outer packaging of the secondary battery may be a hard case, such as a hard plastic case, aluminum case, steel case, and the like.
  • the outer packaging of the secondary battery may also be a soft bag, such as a bag-type soft bag.
  • the material of the soft bag can be plastic, such as one or more of polypropylene, polybutylene terephthalate (PBT), polybutylene succinate (PBS) and the like.
  • FIG. 1 shows a secondary battery 5 with a square structure as an example.
  • the outer package may include a housing 51 and a cover 53 .
  • the housing 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plates enclose to form an accommodating cavity.
  • the housing 51 has an opening communicating with the receiving chamber, and the cover plate 53 is used to cover the opening to close the receiving chamber.
  • the positive pole piece, the negative pole piece and the separator can be formed into an electrode assembly 52 through a winding process or a lamination process.
  • the electrode assembly 52 is packaged in the accommodating cavity. Electrolyte is infiltrated in the electrode assembly 52 .
  • the number of electrode assemblies 52 contained in the secondary battery 5 can be one or several, and can be adjusted according to requirements.
  • the secondary battery can be assembled into a battery module, and the number of secondary batteries contained in the battery module can be multiple, and the specific number can be adjusted according to the application and capacity of the battery module.
  • FIG. 3 is a battery module 4 as an example.
  • a plurality of secondary batteries 5 may be arranged in sequence along the length direction of the battery module 4 .
  • the plurality of secondary batteries 5 may be fixed by fasteners.
  • the battery module 4 may also include a case having a housing space in which a plurality of secondary batteries 5 are accommodated.
  • the above-mentioned battery modules can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be adjusted according to the application and capacity of the battery pack.
  • the battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box.
  • the battery box includes an upper box body 2 and a lower box body 3 , the upper box body 2 is used to cover the lower box body 3 and forms a closed space for accommodating the battery module 4 .
  • Multiple battery modules 4 can be arranged in the battery box in any manner.
  • the second aspect of the present application provides an electric device, the electric device includes at least one of the secondary battery, battery module, or battery pack of the present application.
  • the secondary battery, battery module or battery pack can be used as a power source of the electric device, and can also be used as an energy storage unit of the electric device.
  • the electric device can be, but not limited to, mobile devices (such as mobile phones, notebook computers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.
  • the electric device can select a secondary battery, a battery module or a battery pack according to its usage requirements.
  • FIG. 6 is an example of an electrical device.
  • the electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.
  • a battery pack or a battery module can be used.
  • the electric device may be a mobile phone, a tablet computer, a notebook computer, and the like.
  • the electrical device is usually required to be light and thin, and a secondary battery can be used as a power source.
  • the artificial graphite used in the negative electrode sheet, the conductive agent acetylene black, the binding agent styrene-butadiene rubber (SBR), the thickener sodium carboxymethyl cellulose (CMC-Na) can pass Commercially available.
  • the positive electrode active material lithium iron phosphate, the binder polyvinylidene fluoride (PVDF), the conductive agent acetylene black, and the solvent N-methylpyrrolidone (NMP) used in the positive electrode sheet can all be obtained commercially.
  • the LiPF6, the first organic solvent, the second organic solvent, the first additive, the second additive, and vinyl sulfate (DTD) used in the electrolyte can all be obtained commercially.
  • the polypropylene film used for the separator is commercially available.
  • Negative electrode active material artificial graphite, conductive agent acetylene black, binder styrene-butadiene rubber (SBR), thickener carboxymethylcellulose sodium (CMC-Na) are dissolved in the solvent according to the mass ratio of 95:2:2:1
  • Negative electrode slurry is prepared by fully stirring and mixing in deionized water; the negative electrode slurry is evenly coated on the copper foil of the negative electrode current collector, and then dried, cold pressed, and cut to obtain the negative electrode sheet.
  • the positive electrode active material lithium iron phosphate, the binder polyvinylidene fluoride (PVDF), and the conductive agent acetylene black in the solvent N-methylpyrrolidone (NMP) according to the mass ratio of 97:2:1, and stir and mix evenly
  • NMP N-methylpyrrolidone
  • the compound 1-2, ethylene carbonate (EC), and ethyl methyl carbonate (EMC) were mixed according to the mass ratio of 30: Mix 30:40 evenly to prepare an organic solvent; dissolve a certain amount of LiPF6 and a certain amount of compound 2-4 in the above organic solvent, and stir evenly to obtain an electrolyte.
  • the mass percentage of compound 2-4 in the electrolyte is 2%, and the conductivity of the electrolyte is 13.5 mS/cm.
  • a polypropylene film was used as the separator.
  • the secondary battery has a length of 194 mm, a width of 70 mm, and a height of 112 mm.
  • Example 2-26 and Comparative Examples 1-3 are similar to those of Example 1, except that the relevant parameters of the electrolyte are adjusted, and the specific parameters of the electrolyte are shown in Table 1.
  • the first additive used in the electrolyte solution of Comparative Example 3 is compound 2-9.
  • the batteries of the above-mentioned examples and comparative examples were charged and discharged for the first time with a current of 0.33C (wherein, 1C represents the current value corresponding to the theoretical capacity of the battery completely drained within 1 hour).
  • the specific steps include: charging the battery at a constant current of 0.33C to a voltage of 3.65V, and then charging at a constant voltage of 3.65V to a current ⁇ 0.05C; leaving the battery for 5 minutes, discharging at a constant current of 0.33C to a voltage of 2.5V, recording
  • the actual discharge capacity of the battery is C 0 .
  • the charging cut-off voltage is 3.65V or the potential of the negative electrode drops to 0V (whichever comes first). After each charge is completed, it needs to be discharged at 0.33C 0 to the battery discharge cut-off voltage of 2.5V.
  • Record the charging rate of the battery to 10% SOC, 20% SOC, 30% SOC, 40% SOC, 50% SOC, 60% SOC, 70% SOC, 80% SOC (SOC indicates the state of charge of the battery Charge) corresponding to the negative electrode potential.
  • the charging windows under different states of charge are recorded as C 10%SOC , C 20%SOC , C 30%SOC , C 40%SOC , C 50%SOC , C 60%SOC , C 70%SOC , C 80%SOC .
  • the batteries of the above-mentioned examples and comparative examples were charged at a constant current of 1C to a voltage of 3.65V, then charged at a constant voltage of 3.65V to a current ⁇ 0.05C, and then discharged at a constant current of 1C to a voltage of 2.5V, this is a charge and discharge process, and the discharge capacity at this time is recorded as the discharge capacity of the battery for the first cycle.
  • the charge and discharge cycles are repeated in this way, and the capacity retention rate of the battery after 500 cycles is calculated.
  • the capacity retention (%) of the battery after 500 cycles at 60°C (the discharge capacity of the battery at the 500th cycle/the discharge capacity of the battery at the first cycle) ⁇ 100%.
  • the batteries of the above-mentioned examples and comparative examples were charged at a constant current of 0.33C to a voltage of 3.65V, then charged at a constant voltage of 3.65V to a current ⁇ 0.05C, and then discharged at a constant current of 0.33C to The voltage is 2.5V, and the actual discharge capacity of the recorded battery is C 0 .
  • the batteries of the above-mentioned examples and comparative examples were charged at a constant current of 0.33C to a voltage of 3.65V, then charged at a constant voltage of 3.65V to a current ⁇ 0.05C, and then discharged at a constant current of 0.33C to The voltage is 2.5V, and the actual discharge capacity of the recorded battery is C 0 .
  • Volume before storage Store the fully charged battery in an incubator at 60° C. After
  • Capacity retention rate of the battery after storage at 60°C for 60 days (discharge capacity of the battery after storage for 60 days/actual discharge capacity C 0 of the battery) ⁇ 100%.
  • DTD will form a stable interfacial film on the surface of both the positive electrode active material and the negative electrode active material, inhibiting the continuous reaction between the negative electrode and the first organic solvent; but DTD will also generate gas during the formation of the interfacial film.
  • the generated gas will be enriched at the interface of the positive electrode, the negative electrode, and the separator to form macroscopic bubbles, which will block the transmission of lithium ions.
  • the batteries of Examples 1-26 can significantly improve the cycle performance and storage performance of the battery, especially the high-temperature cycle performance and high-temperature storage performance of the battery, by using the first additive instead of DTD; , the batteries of Examples 1-26 still maintain good fast charging performance.
  • the first additive has a higher reduction potential, which can form a dense and stable sulfur-containing organic interfacial film on the surface of the negative electrode active material in preference to the first organic solvent, and inhibit the continuous reaction between the first organic solvent and the negative electrode. Gas production will decrease when the battery is stored at high temperature.
  • the first additive has a ring structure.
  • the thickness of the film on the surface of the negative electrode active material will increase, and the film resistance will increase slightly, which will affect the transmission speed of lithium ions at the negative electrode interface, so the charging time of the battery will be reduced to a certain extent. increase, the high-temperature storage capacity retention rate and high-temperature cycle capacity retention rate of the battery will decrease to a certain extent.
  • Negative electrode active material artificial graphite (volume average particle diameter Dv50 is 17 ⁇ m), conductive agent acetylene black, binder styrene-butadiene rubber (SBR), thickener carboxymethylcellulose sodium (CMC-Na) according to the mass ratio of 95 : 2:2:1 dissolved in solvent deionized water, fully stirred and mixed evenly to prepare negative electrode slurry; the negative electrode slurry is evenly coated on both surfaces of the negative electrode current collector copper foil, and then dried, cold pressed , cutting to obtain the negative electrode sheet.
  • the negative electrode slurry was dried to form a negative electrode film layer, the thickness of one side of the negative electrode film layer was 60 ⁇ m, and the compacted density of the negative electrode film layer was 1.65 g/cm 3 .
  • the positive electrode active material lithium iron phosphate, the binder polyvinylidene fluoride (PVDF), and the conductive agent acetylene black in the solvent N-methylpyrrolidone (NMP) according to the mass ratio of 97:2:1, and stir and mix evenly
  • NMP N-methylpyrrolidone
  • the compound 1-2, ethylene carbonate (EC), and ethyl methyl carbonate (EMC) were mixed according to the mass ratio of 30: Mix 30:40 evenly to prepare an organic solvent; dissolve a certain amount of LiPF 6 and a certain amount of the first additive compound 2-4 in the above organic solvent, and stir evenly to obtain an electrolyte.
  • the mass percentage of compound 2-4 in the electrolyte is 2%, and the conductivity of the electrolyte is 13.5 mS/cm.
  • a polypropylene film was used as the separator.
  • the secondary battery has a length of 194 mm, a width of 70 mm, and a height of 112 mm.
  • Examples 28-37 are similar to those of Example 27, except that the relevant parameters of the negative electrode sheet are adjusted, and the specific parameters are shown in Table 3.
  • the volumetric energy density of the battery discharge energy Q/volume V of the battery, and the unit of the volumetric energy density is Wh/L.
  • the ratio H/Dv50 of the thickness of the single-sided negative electrode film layer and the volume average particle diameter Dv50 of the negative electrode active material is limited within a suitable range, and then the electrolyte solution of the present application can be matched to make the battery have both good fast charging performance, Long service life and high energy density.
  • the present application is not limited to the above-mentioned embodiments.
  • the above-mentioned embodiments are merely examples, and within the scope of the technical solutions of the present application, embodiments that have substantially the same configuration as the technical idea and exert the same effects are included in the technical scope of the present application.
  • various modifications conceivable by those skilled in the art are added to the embodiments, and other forms constructed by combining some components in the embodiments are also included in the scope of the present application. .

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Abstract

提供了一种电解液、二次电池、电池模块、电池包和用电装置，电解液包括有机溶剂以及添加剂，有机溶剂包括式(1)所示的第一有机溶剂，添加剂包括第一添加剂，第一添加剂选自式(2A)、式(2B)所示化合物中的一种或几种。在式(1)中，R1和R2分别独立地为C1~C3烷基、C1~C3卤代烷基中的一种；在式(2A)中，R21、 R22、 R23、 R24分别独立地为单键、亚甲基中的一种；在式(2B)中，R31、R32、R33、R34分别独立地为单键、亚甲基中的一种，R4为单键、-O-、C1~C3亚烷基、C1~C3卤代亚烷基、C1~C3氧杂亚烷基中的一种。二次电池在具有长循环寿命和存储寿命的前提下，还同时兼具良好的快速充电性能。 <

Description

电解液、二次电池、电池模块、电池包和用电装置 技术领域
本申请属于二次电池技术领域，具体涉及一种电解液、二次电池、电池模块、电池包和用电装置。
背景技术
全球气候变化和环境污染问题日益严重，基于电池驱动的电动汽车因其绿色无污染的突出特点得到蓬勃发展。然而，与传统燃油汽车能快速及时地加油相比，电动汽车的充电时间往往较长，原因在于电动汽车一般是以较小的倍率进行充电。电动汽车的这一问题不仅给消费者造成了续航里程的焦虑，还限制了电动汽车的快速普及。
发明内容
本申请的目的在于提供一种电解液、二次电池、电池模块、电池包和用电装置，旨在使所述电池在具有长循环寿命和存储寿命的前提下，同时兼具良好的快速充电性能。
本申请第一方面提供一种电解液，所述电解液包括有机溶剂以及添加剂。所述有机溶剂包括式1所示的第一有机溶剂，在式1中，R 1和R 2分别独立地为C1～C3烷基、C1～C3卤代烷基中的一种。所述添加剂包括第一添加剂，所述第一添加剂选自式2A、式2B所示化合物中的一种或几种，在式2A中，R 21、R 22、R 23、R 24分别独立地为单键、亚甲基中的一种，在式2B中，R 31、R 32、R 33、R 34分别独立地为单键、亚甲基中的一种，R 4为单键、-O-、C1～C3亚烷基、C1～C3卤代亚烷基、C1～C3氧杂亚烷基中的一种。
Figure PCTCN2021109905-appb-000001
将第一添加剂与第一有机溶剂配合使用，可以在充分发挥第一有机溶剂对电解液电导率提升作用的同时，保证电池具有良好的循环性能和存储性能。
在本申请任意实施方式中，在式1中，R 1和R 2分别独立地为甲基、乙基、丙基、氟代甲基、氟代乙基、氟代丙基中的一种。选取合适的第一有机溶剂，可以使电解液的粘度保持在合适的范围内，因此，电解液具有更高的电导率，电池具有更好的快速充电性能。
在本申请任意实施方式中，第一有机溶剂选自如下化合物中的一种或几种：
Figure PCTCN2021109905-appb-000002
选取上述化合物作为第一有机溶剂，能使电解液的粘度适中、电导率更高。
在本申请任意实施方式中，第一有机溶剂选自如下化合物中的一种或两种：
Figure PCTCN2021109905-appb-000003
化合物1-1和化合物1-2具有更低的粘度，对电解液电导率的提高作用更为明显。
在本申请任意实施方式中，在式2A中，R 21、R 22、R 23、R 24分别独立地为单键、亚甲基中的一种。
可选地，R 21、R 22、R 23、R 24不同时为单键。
更具体地，R 21、R 22中的一个或两个为亚甲基，R 23、R 24中的一个或两个为亚甲基。
在本申请任意实施方式中，在式2B中，R 31、R 32、R 33、R 34分别独立地为单键、亚甲基中的一种，且R 31、R 32、R 33、R 34不同时为单键。
在本申请任意实施方式中，在式2B中，R 4为单键、-O-、亚甲基、亚乙基、亚丙基、氟代亚甲基、氟代亚乙基、氟代亚丙基、亚甲氧基、亚乙氧基、亚丙氧基中的一种。
可选地，R 4为单键、亚甲基、亚乙基、亚丙基中的一种。
取代基在上述范围内的第一添加剂，能在负极活性材料表面形成致密、稳定的界面膜，阻断第一有机溶剂和负极活性材料直接接触，因此能进一步提高活性离子在正负极极片之间脱嵌的可逆性，提高电池的放电容量和循环性能。
在本申请任意实施方式中，R 4为单键时，R 31、R 32中的一个或两个为亚甲基，其余为单键。
在本申请任意实施方式中，R 4为单键时，R 33、R 34中的一个或两个为亚甲基，其余为单键。
在本申请任意实施方式中，R 4为单键时，R 31、R 32中的一个为亚甲基，R 33、R 34中的一个为亚甲基，其余为单键。
在本申请任意实施方式中，R 4为单键时，R 31、R 32均为亚甲基，R 33、R 34中的一个为亚甲基，其余为单键。
在本申请任意实施方式中，R 4为单键时，R 33、R 34均为亚甲基，R 31、R 32中的一个为亚甲基，其余为单键。
在本申请任意实施方式中，R 4为单键时，R 31、R 32、R 33、R 34均为亚甲基。
在本申请任意实施方式中，第一添加剂选自如下化合物中的一种或几种：
Figure PCTCN2021109905-appb-000004
上述第一添加剂能在负极活性材料表面形成稳定持久的界面膜，进一步提高电池的循环性能和存储性能。
在本申请任意实施方式中，可选地，第一添加剂选自如下化合物中的一种或几种：
Figure PCTCN2021109905-appb-000005
在本申请任意实施方式中，其中，基于所述有机溶剂的总质量，第一有机溶剂的质量百分数为w1，w1的范围为20％～80％。可选地，w1的范围为30％～70％。第一有机溶剂的质量百分数控制在合适的范围内，可以在提高电池快速充电性能的同时，使电池具有良好的循环性能和存储性能。
在本申请任意实施方式中，基于所述电解液的总质量，第一添加剂的质量百分数为w2，w2的范围为0.1％～10％。可选地，w2的范围为0.5％～5％。第一添加剂的质量百分数控制在合适的范围内，能使电池兼具良好的快速充电性能、循环性能及存储性能。
在本申请任意实施方式中，所述添加剂还包括第二添加剂，所述第二添加剂含有不饱和键的环状碳酸酯化合物、卤素取代的环状碳酸酯化合物、硫酸酯化合物、亚硫酸酯化合物、磺酸内酯化合物、二磺酸化合物、腈化合物、芳香化合物、异氰酸酯化合物、磷腈化合物、环状酸酐化合物、亚磷酸酯化合物、磷酸酯化合物、硼酸酯化合物、羧酸酯化合物中的一种或几种。这些第二添加剂可以在正极活性材料和/或负极活性材料表面形成更为致密稳定的界面膜，有助于进一步提升电池的循环性能和存储性能。
在本申请任意实施方式中，所述第二添加剂包括如下化合物中的一种或两种：
Figure PCTCN2021109905-appb-000006
当电解液中包含以上两种化合物中的一种或两种时，能进一步增强电池的循环性能和存储性能。
在本申请任意实施方式中，基于所述电解液的总质量，第二添加剂的质量百分数为w3，w3的范围为≤10％。可选地，w3的范围为≤5％。第二添加剂的质量百分数控制在合适的范围内，能进一步增强电池的循环性能。
在本申请任意实施方式中，所述有机溶剂还包括第二有机溶剂，所述第二有机溶剂包括环状碳酸酯化合物、链状碳酸酯化合物中的一种或几种。可选地，所述第二有机溶剂包括环状碳酸酯化合物、或包括环状碳酸酯化合物与链状碳酸酯化合物的组合。有机溶剂还包括上述第二有机溶剂，能使包含该电解液的电池具有良好的快速充电性能。
在本申请任意实施方式中，所述第二有机溶剂包括碳酸乙烯酯、碳酸丙烯酯、碳酸1，2-丁烯酯、碳酸二甲酯、碳酸甲乙酯、碳酸二乙酯、碳酸二丙酯、碳酸甲丙酯、碳酸乙丙酯中的一种或几种。电解液中包含上述化合物组成的第二有机溶剂，可以使包含该电解液的电池具有更好的快速充电性能。
在本申请任意实施方式中，基于所述有机溶剂的总质量，环状碳酸酯化合物的质量百分数为w4，w4的范围为20％～80％。可选地，w4的范围为20％～50％。环状碳酸酯化合物的介电常数较高，有利于锂盐的解离。环状碳酸酯化合物的质量百分数控制在合适的范围内，能使包含该电解液的电池具有更优异的快速充电性能。
在本申请任意实施方式中，电解液还包括锂盐，所述锂盐包括LiN(C xF 2x+1SO 2)(C yF 2y+1SO 2)、LiPF 6、LiBF 4、LiBOB、LiDFOB、LiPO 2F 2、LiDFOP、LiTFOP、LiAsF 6、Li(FSO 2) 2N、LiCF 3SO 3以及LiClO 4中的一种或几种，其中，x、y为正整数。电解液中包括上述锂盐，可以帮助电池负极活性材料表面形成均匀、致密、阻抗小的界面膜，有效提高电池的快速充电性能和循环性能。
在本申请任意实施方式中，所述电解液的电导率满足≥12mS/cm。可选地，所述电解液的电导率满足≥13mS/cm。电解液的电导率控制在合适的范围内，能使电池具有良好的快速充电性能、循环性能、存储性能以及安全性能。
在本申请任意实施方式中，所述电解液的电导率为12mS/cm～24mS/cm。可选地，所述电解液的电导率为13mS/cm～20mS/cm。
本申请第二方面提供一种二次电池，其包括本申请第一方面的电解液。
本申请的二次电池包括本申请第一方面的电解液，所述二次电池在具有良好的快速充电性能的同时，还兼具了优异的循环性能和存储性能。
在本申请任意实施方式中，二次电池包括负极极片，负极极片包括负极集流体以及设置在负极集流体至少一个表面上且包括负极活性材料的负极膜层。单面负极膜层的厚度H与负极活性材料的体积平均粒径Dv50的比值H/Dv50满足≥3。可选地，H/Dv50满足≥3.5。更具体地，H/Dv50的范围满足4≤H/Dv50≤9。H/Dv50的取值在合适的范围内，可以在保证二次电池具有较高体积能量密度的基础上，进一步提升二次电池快速充 电性能。
在本申请任意实施方式中，单面负极膜层的厚度H满足≥60μm。可选地，单面负极膜层的厚度H满足≥65μm。单面负极膜层的厚度H在合适的范围内，能进一步提高电池的能量密度。
在本申请任意实施方式中，负极活性材料的体积平均粒径Dv50满足≤18μm。可选地，负极活性材料的体积平均粒径Dv50满足14μm≤Dv50≤18μm。负极活性材料的体积平均粒径Dv50在合适的范围内，既能提高活性离子的扩散系数，又能减小负极膜层与电解液的接触面积，电池能同时具有良好的快速充电性能、循环性能和存储性能。
在本申请任意实施方式中，负极膜层的压实密度为1.4g/cm 3～1.85g/cm 3。可选地，负极膜层的压实密度为1.6g/cm 3～1.8g/cm 3。负极膜层的压实密度在合适的范围内，能使电池兼具高能量密度和良好的快速充电性能。
在本申请任意实施方式中，二次电池包括正极极片，正极极片包括正极活性材料，正极活性材料包括锂过渡金属氧化物、橄榄石结构的含锂磷酸盐及其各自的改性化合物中的一种或几种。
在本申请任意实施方式中，橄榄石结构的含锂磷酸盐包括磷酸铁锂、磷酸铁锂与碳的复合材料、磷酸锰锂、磷酸锰锂与碳的复合材料、磷酸锰铁锂、磷酸锰铁锂与碳的复合材料及其改性化合物中的一种或几种。在正极膜层中使用这些正极活性材料，能在提升电池循环性能和存储性能的同时，提升电池的倍率性能和能量密度。
本申请第三方面提供一种电池模块，其包括本申请第二方面的二次电池。
本申请第四方面提供一种电池包，其包括本申请第二方面的二次电池、第三方面的电池模块中的一种。
本申请第五方面提供一种用电装置，其包括本申请第二方面的二次电池、第三方面的电池模块、第四方面的电池包中的至少一种。
本申请的电池模块、电池包和用电装置包括本申请提供的二次电池，因而至少具有与所述二次电池相同的优势。
附图说明
为了更清楚地说明本申请实施例的技术方案，下面将对本申请实施例中所需要使用的附图作简单地介绍，显而易见地，下面所描述的附图仅仅是本申请的一些实施方式，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据附图获得其他的附图。
图1是本申请的二次电池的一实施方式的示意图。
图2是本申请的二次电池的一实施方式的分解示意图。
图3是本申请的电池模块的一实施方式的示意图。
图4是本申请的电池包的一实施方式的示意图。
图5是图4的分解图。
图6是本申请的二次电池用作电源的用电装置的一实施方式的示意图。
具体实施方式
为了使本申请的发明目的、技术方案和有益技术效果更加清晰，以下结合实施例对本申请进行进一步详细说明。应当理解的是，本说明书中描述的实施例仅仅是为了解释本申请，并非为了限定本申请。
为了简便，本文仅明确地公开了一些数值范围。然而，任意下限可以与任何上限组合形成未明确记载的范围；以及任意下限可以与其它下限组合形成未明确记载的范围，同样任意上限可以与任意其它上限组合形成未明确记载的范围。此外，尽管未明确记载，但是范围端点间的每个点或单个数值都包含在该范围内。因而，每个点或单个数值可以作为自身的下限或上限与任意其它点或单个数值组合或与其它下限或上限组合形成未明确记载的范围。
在本文的描述中，需要说明的是，除非另有说明，“以上”、“以下”为包含本数，“一种或几种”中“几种”的含义是两种或两种以上。
在本文的描述中，除非另有说明，术语“或”是包括性的。举例来说，短语“A或B”表示“A，B，或A和B两者”。更具体地，以下任一条件均满足条件“A或B”：A为真(或存在)并且B为假(或不存在)；A为假(或不存在)而B为真(或存在)；或A和B都为真(或存在)。
应理解，术语“第一”、“第二”、等之类的关系术语仅仅用来将一个实体或者操作与另一个实体或操作区分开来，而不一定要求或暗示这些实体或操作之间存在任何实际的关系或顺序。
本申请的上述发明内容并不意欲描述本申请中的每个公开的实施方式或每种实现方式。如下描述更具体地举例说明示例性实施方式。在整篇申请中的多处，通过一系列实施例提供了指导，这些实施例可以以各种组合形式使用。在各个实例中，列举仅作为代表性组，不应解释为穷举。
[二次电池]
二次电池又称为充电电池或蓄电池，是指在电池放电后可通过充电的方式使活性材料激活而继续使用的电池。
通常情况下，二次电池包括正极极片、负极极片、隔离膜及电解液。在电池充放电过程中，活性离子(例如锂离子)在正极极片和负极极片之间往返嵌入和脱出。隔离膜设置在正极极片和负极极片之间，主要起到防止正负极短路的作用，同时可以使活性离子通过。电解液在正极极片和负极极片之间，主要起到传导活性离子的作用。
[电解液]
二次电池包括电解液，电解液是二次电池中活性离子通行的桥梁，在电池中承担着正负极之间输送活性离子的作用，对电池的快速充电性能、比容量、循环效率及安全性能等都起着至关重要的作用。
发明人发现，影响电池快速充电性能的重要因素之一是电解液的电导率。在电解液中加入羧酸酯能提升电解液的电导率和电池的快速充电性能，这是由于羧酸酯具有低粘度、高介电常数的优点，将其应用于电解液中，能够提高电解液的离子电导性。然而，羧酸酯与负极不兼容，羧酸酯上的α-H容易和在负极还原得到的活性锂反应，造成活性锂损失，影响电池的循环性能和存储性能，尤其在高温环境下对循环性能和存储性能的恶化更明显。此外，羧酸酯的耐氧化能力较差，在高荷电状态存储时容易发生氧化 分解，进一步影响电池的存储性能。为了减少羧酸酯对电池循环性能和存储性能的负面影响，现有技术报道了在电解液中加入环状硫酸酯，环状硫酸酯可以在正极活性材料和负极活性材料表面均形成界面膜，阻断正极活性材料、负极活性材料与电解液的直接接触，抑制负极与电解液中的羧酸酯发生持续反应。但是，常规的环状硫酸酯在形成界面膜的过程中也会产生气体，这些持续产生的气体会在正极极片、负极极片与隔离膜的界面处富集而形成宏观上的气泡，这些气泡会阻断活性离子的传输，因此也会影响电池的循环性能和存储性能。
发明人进一步进行了大量研究，巧妙地在包含羧酸酯的电解液中加入了式2A和/或式2B所示的第一添加剂，打破了上述瓶颈。本申请的电解液能在充分发挥羧酸酯对电解液电导率以及电池快速充电性能提升作用的同时，保证电池具有良好的循环性能和存储性能，尤其是保证电池在高温环境下仍具有良好的循环性能和存储性能。
具体地，本申请的电解液包括有机溶剂以及添加剂，其中，所述有机溶剂包括式1所示的第一有机溶剂，所述添加剂包括第一添加剂，所述第一添加剂选自式2A、式2B所示化合物中的一种或几种。具体地，在一些实施方式中，所述第一添加剂选自式2A所示化合物中的一种或几种；在一些实施方式中，所述第一添加剂选自式2B所示化合物中的一种或几种；在一些实施方式中，所述第一添加剂同时包括式2A所示化合物和式2B所示化合物。
Figure PCTCN2021109905-appb-000007
在式1中，R 1和R 2分别独立地为C1～C3烷基、C1～C3卤代烷基中的一种，R 1和R 2可以相同，也可以不同。烷基和卤代烷基可以是直链结构，也可以是支链结构。卤代烷基中的卤原子数目可以是一个，也可以是多个；在卤代烷基中存在多个卤原子时，这些卤原子可以相同，也可以不同。
Figure PCTCN2021109905-appb-000008
在式2A中，R 21、R 22、R 23、R 24分别独立地为单键、亚甲基(-CH 2-)中的一种。R 21、R 22、R 23、R 24可以相同，也可以不同。
在式2B中，R 31、R 32、R 33、R 34分别独立地为单键、亚甲基中的一种，R 4为单键、-O-、C1～C3亚烷基、C1～C3卤代亚烷基、C1～C3氧杂亚烷基中的一种。亚烷基、卤代亚烷基、氧杂亚烷基可以是直链结构，也可以是支链结构。卤代亚烷基中的卤原子数目可以是一个，也可以是多个；在卤代亚烷基中存在多个卤原子时，这些卤原子可以相同，也可以不同。氧杂亚烷基中的氧原子数目可以是一个，也可以是多个。
当R 31、R 32、R 33、R 34为单键时，表示R 4直接与R 31、R 32、R 33、R 34相邻的-O-以单键进行了键合。R 31、R 32、R 33、R 34可以相同，也可以不同，
本申请的电解液中加入了第一添加剂，其具有较高的还原电位，可以在充电期间接受来自负极的电子而自身还原，并优先于第一有机溶剂在负极活性材料表面形成致密、稳定的含硫有机物界面膜，抑制第一有机溶剂与在负极还原得到活性锂反应。第一 添加剂的热稳定性高，在形成含硫有机物界面膜的过程中不会产生气体，不会影响电池的循环性能和存储性能，尤其是高温环境下的循环性能和存储性能。第一添加剂还可以优先于第一有机溶剂在正极活性材料表面形成界面膜，抑制第一有机溶剂在正极的氧化分解；第一添加剂还可以和正极活性材料表面的过渡金属配位形成络合物，使正极活性材料表面形成的界面膜更为致密、稳定，有效阻止有机溶剂(尤其是第一有机溶剂)与正极活性材料的直接接触。
将第一添加剂与第一有机溶剂配合使用，可以在充分发挥第一有机溶剂对电解液电导率提升作用的同时，保证电池具有良好的循环性能和存储性能。因此，本申请的电解液可以使电池兼具优异的快速充电性能及良好的循环性能和存储性能。
不期望受任何理论限制，发明人在研究过程中首次发现，在电解液中加入的第一添加剂，其在抑制第一有机溶剂与负极反应、保证电池具有良好的循环性能和存储性能方面的作用远优于现有技术中使用的常规的环状硫酸酯(例如，硫酸乙烯酯DTD)。
在一些实施方式中，在式1中，R 1和R 2可分别独立地为甲基、乙基、丙基、氟代甲基、氟代乙基、氟代丙基中的一种。R 1和R 2可相同，也可不同。氟原子数目可以是一个，也可以是多个。R 1和R 2选自上述基团时，可以使电解液的粘度保持在合适的范围内，因此，电解液具有更高的电导率，电池具有更好的快速充电性能。
在一些实施方式中，第一有机溶剂可选自如下化合物中的一种或几种：
Figure PCTCN2021109905-appb-000009
发明人发现，当电解液包括上述化合物中的一种或几种时，电解液的粘度适中，电导率更高，从而能显著提升电池的快速充电性能。
在一些实施方式中，第一有机溶剂可选自如下化合物中的一种或两种：
Figure PCTCN2021109905-appb-000010
发明人经过深入研究发现，化合物1-1和化合物1-2具有更低的粘度，因此，对电解液电导率的提高作用更为明显，进而能使电池具备更优良的快速充电性能。
在一些实施方式中，基于所述有机溶剂的总质量，第一有机溶剂的质量百分数为w1，w1的范围可为20％～80％。例如，w1的范围可为25％～80％、25％～75％，30％～70％，30％～60％，35％～65％，35％～60％，40％～60％，或50％～60％。充分考虑到第一有机溶剂对电解液电导率的提高作用与其对电池循环性能和存储性能的负面影响，发明人将第一有机溶剂的质量百分数控制在合适的范围内，可以在提高电池快速充电性能的同时，使电池具有良好的循环性能和存储性能。
在一些实施方式中，在式2A中，R 21、R 22、R 23、R 24不同时为单键。可选地， R 21、R 22中的一个或两个为亚甲基，R 23、R 24中的一个或两个为亚甲基。
在一些实施方式中，R 21、R 23为亚甲基，R 22、R 24为单键。
在一些实施方式中，R 21、R 23为亚甲基，R 22、R 24中的一个为亚甲基，其余为单键。
在一些实施方式中，R 21、R 22、R 23、R 24均为亚甲基。
在一些实施方式中，在式2B中，R 31、R 32、R 33、R 34可分别独立地为单键、亚甲基中的一种，且R 31、R 32、R 33、R 34不同时为单键。
在一些实施方式中，在式2B中，R 31、R 32、R 33、R 34中的至少两个为亚甲基。
在一些实施方式中，在式2B中，R 4可为单键、O-、亚甲基、亚乙基、亚丙基、氟代亚甲基、氟代亚乙基、氟代亚丙基、亚甲氧基、亚乙氧基、亚丙氧基中的一种。可选地，R 4为单键、亚甲基、亚乙基、亚丙基中的一种。这些取代基既可以是直链结构，也可以是支链结构。氟原子数目可以是一个，也可以是多个。
这些取代基落入上述范围内时，第一添加剂能在正极活性材料和负极活性材料表面形成致密、稳定的界面膜，阻断第一有机溶剂与正极活性材料和负极活性材料直接接触，降低活性锂损失，从而能进一步提高活性离子在正负极极片之间脱嵌的可逆性，提高电池的放电容量和循环性能。
在一些实施方式中，R 4为单键时，R 31、R 32中的一个或两个为亚甲基，其余为单键。
在一些实施方式中，R 4为单键时，R 33、R 34中的一个或两个为亚甲基，其余为单键。
在一些实施方式中，R 4为单键时，R 31、R 32中的一个为亚甲基，R 33、R 34中的一个为亚甲基，其余为单键。
在一些实施方式中，R 4为单键时，R 31、R 32均为亚甲基，R 33、R 34中的一个为亚甲基，其余为单键。
在一些实施方式中，R 4为单键时，R 33、R 34均为亚甲基，R 31、R 32中的一个为亚甲基，其余为单键。
在一些实施方式中，R 4为单键时，R 31、R 32、R 33、R 34均为亚甲基。
在一些实施方式中，第一添加剂可选自如下化合物中的一种或几种：
Figure PCTCN2021109905-appb-000011
发明人发现，以上述化合物中的一种或几种为第一添加剂，能在正极活性材料和负极活性材料表面形成更为稳定持久的界面膜；甚至在长时间充放电后所述界面膜仍能有效阻止有机溶剂(尤其是第一有机溶剂)与正极活性材料和负极活性材料直接接触，因此，能进一步提高电池的循环性能和存储性能。
在一些实施方式中，第一添加剂选自如下化合物中的一种或几种：
Figure PCTCN2021109905-appb-000012
在一些实施方式中，第一添加剂选自如下化合物中的一种或两种：
Figure PCTCN2021109905-appb-000013
在一些实施方式中，基于所述电解液的总质量，第一添加剂的质量百分数为w2，w2可≤10％。例如，w2的范围可为0.05％～10％，0.1％～10％，0.5％～10％，0.5％～8％，0.5％～5％，1％～5％，或2％～5％。第一添加剂的质量百分数在合适的范围内，可以充分发挥第一添加剂与第一有机溶剂的协同作用。第一添加剂的质量百分数较大，负极活性材料表面成膜厚度较大，会影响活性离子在负极界面的传输速度，可能对电池快速充电性能的提升不明显；第一添加剂的质量百分数较小，无法有效抑制第一有机溶剂与负极持续发生反应，可能对电池循环性能和存储性能的改善不明显。发明人通过创造性的劳动，选取了第一添加剂的质量百分数范围，从而使电池兼具良好的快速充电性能、循环性能和存储性能。
在一些实施方式中，所述添加剂还可包括第二添加剂。所述第二添加剂可包括含有不饱和键的环状碳酸酯化合物、卤素取代的环状碳酸酯化合物、硫酸酯化合物、亚硫酸酯化合物、磺酸内酯化合物、二磺酸化合物、腈化合物、芳香化合物、异氰酸酯化合物、磷腈化合物、环状酸酐化合物、亚磷酸酯化合物、磷酸酯化合物、硼酸酯化合物、羧酸酯化合物中的一种或几种。这些第二添加剂可以在正极活性材料和/或负极活性材料表面形成更为致密稳定的界面膜，有助于进一步提升电池的循环性能和存储性能。
在一些实施方式中，所述第二添加剂可包括如下化合物中的一种或两种：
Figure PCTCN2021109905-appb-000014
当第二添加剂包含以上两种化合物中的一种或两种时，能进一步增强电池的循环性能和存储性能。
在一些实施方式中，基于所述电解液的总质量，所述第二添加剂的质量百分数为w3，w3的范围可为≤10％。例如，w3的范围可≤9％，≤8％，≤7％，≤6％，≤5％，≤4％， ≤3％，≤2％，或≤1％。
在一些实施方式中，基于所述电解液的总质量，所述第二添加剂的质量百分数w3可为1％～10％，1％～8％，1％～7％，1％～5％，1％～4％，1％～3％，或1％～2％。
第二添加剂的质量百分数在合适的范围内，能进一步增强电池的循环性能和存储性能。
在一些实施方式中，所述有机溶剂还可包括第二有机溶剂，所述第二有机溶剂可包括环状碳酸酯化合物、链状碳酸酯化合物中的一种或几种。可选地，所述第二有机溶剂可包括环状碳酸酯化合物，或包括环状碳酸酯化合物与链状碳酸酯化合物的组合。
本申请对链状碳酸酯化合物、环状碳酸酯化合物的种类没有具体的限制，可根据实际需求进行选择。在一些实施方式中，所述第二有机溶剂可包括碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、碳酸1，2-丁烯酯(BC)、碳酸二甲酯(DMC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)、碳酸二丙酯(DPC)、碳酸甲丙酯(MPC)、碳酸乙丙酯(EPC)中的一种或几种。当本申请的有机溶剂还包括这些第二有机溶剂时，能使电池具有良好的快速充电性能。
在一些实施方式中，基于所述有机溶剂的总质量，所述第二有机溶剂的质量百分数的范围可为20％～80％。可选地，所述第二有机溶剂的质量百分数的范围为20％～75％、25％～75％，30％～70％，40％～70％，35％～65％，40％～65％，40％～60％，或40％～50％。
在一些实施方式中，基于所述有机溶剂的总质量，所述环状碳酸酯化合物的质量百分数为w4，w4的范围可为20％～80％。例如，w4的范围可为20％～50％，25％～50％，25％～45％，25％～40％，25％～35％，30％～50％，30％～45％，或30％～40％。
环状碳酸酯化合物的介电常数较高，有利于锂盐的解离。当环状碳酸酯化合物的质量百分数控制在合适的范围内时，能使包含该电解液的电池具有更优异的快速充电性能。
在一些实施方式中，基于所述有机溶剂的总质量，所述链状碳酸酯化合物的质量百分数的范围可为0％～50％，0％～40％，0％～30％，0％～25％，0％～20％，10％～50％，10％～40％，10％～30％，或10％～20％。
在一些实施方式中，所述电解液还包括锂盐。本申请对锂盐的种类没有具体的限制，可根据实际需求进行选择。作为示例，所述锂盐可包括LiN(C xF 2x+1SO 2)(C yF 2y+1SO 2)、LiPF 6、LiBF 4、LiBOB、LiDFOB、LiPO 2F 2、LiDFOP、LiTFOP、LiAsF 6、Li(FSO 2) 2N、LiCF 3SO 3以及LiClO 4中的一种或几种，其中，x、y为正整数。当电解液包括上述锂盐时，可以帮助在负极活性材料表面形成均匀、致密、阻抗小的界面膜，有效提高电池的快速充电性能和循环性能。
在一些实施方式中，所述电解液的电导率可满足≥12mS/cm。例如，所述电解液的电导率可满足≥12mS/cm，≥13mS/cm，≥14mS/cm，≥15mS/cm，≥16mS/cm，≥17mS/cm，≥18mS/cm，≥19mS/cm，或≥20mS/cm。
当电解液的电导率在合适的范围内时，电池能具有良好的快速充电性能、循环性能、存储性能以及安全性能。
在一些实施方式中，所述电解液的电导率可为12mS/cm～24mS/cm。例如，所述 电解液的电导率可为12mS/cm～23mS/cm，12mS/cm～22mS/cm，12mS/cm～21mS/cm，12mS/cm～20mS/cm，或13mS/cm～20mS/cm。
[负极极片]
二次电池包括负极极片，负极极片通常包括负极集流体以及设置在负极集流体至少一个表面上且包括负极活性材料的负极膜层。
单面负极膜层的厚度H与负极活性材料的体积平均粒径Dv50的比值H/Dv50可以用于表征单位负极膜层的纵向颗粒数。
发明人发现，含有负极活性材料的单位负极膜层的纵向颗粒数越多，活性离子的扩散系数越高，电池的快速充电性能越好；但是，含有负极活性材料的单位负极膜层的纵向颗粒数越多，负极膜层与电解液的接触面积增加，电解液在负极活性材料颗粒表面的副反应也增加，会在一定程度上影响电池的循环性能和存储性能。反之，含有负极活性材料的单位负极膜层的纵向颗粒数越少，电池的快速充电性能相应越差，电池的循环性能和存储性能有所提高。
发明人进行了大量的研究，选取了合适的H/Dv50的范围。具体地，本申请的二次电池的负极极片，单面负极膜层的厚度H与负极活性材料的体积平均粒径Dv50的比值H/Dv50满足≥3。例如，H/Dv50满足≥4，≥5，≥6，≥7，≥8，或≥9。H/Dv50的取值在合适的范围内，可以在保证二次电池具有较高体积能量密度的基础上，进一步提升二次电池快速充电性能。
在一些实施方式中，单面负极膜层的厚度H与负极活性材料的体积平均粒径Dv50的比值H/Dv50可满足4≤H/Dv50≤9。限定单面负极膜层的厚度H与负极活性材料的体积平均粒径Dv50的比值H/Dv50在合适的范围内，再搭配本申请的电解液，能获得兼具优异快速充电性能、长使用寿命和高能量密度的二次电池。
在一些实施方式中，单面负极膜层的厚度H可满足≥60μm。可选地，单面负极膜层的厚度可满足≥65μm。更具体地，单面负极膜层的厚度H可满足≥70μm。单面负极膜层的厚度H控制在合适的的范围内，能进一步改善电池能量密度。
在一些实施方式中，负极活性材料的体积平均粒径Dv50可满足≤18μm。可选地，负极活性材料的体积平均粒径Dv50可满足14μm≤Dv50≤18μm。在单面负极膜层的厚度H一定的情况下，负极活性材料的体积平均粒径Dv50越小，活性离子的扩散系数越高；但是，负极活性材料的体积平均粒径Dv50也不宜太小，这会增加负极膜层与电解液的接触面积，进而影响电池的循环性能和存储性能。负极活性材料的体积平均粒径Dv50在合适的范围内，既能提高活性离子的扩散系数，又能减小负极膜层与电解液的接触面积，因此，电池能同时具有良好的快速充电性能、循环性能和存储性能。
在一些实施方式中，负极膜层的压实密度为1.4g/cm 3～1.85g/cm 3。可选地，负极膜层的压实密度为1.6g/cm 3～1.8g/cm 3。负极膜层的压实密度控制在合适的范围内，能使负极膜层中的负极活性材料颗粒紧密接触，提高单位体积内的负极活性材料含量，由此提升电池的能量密度。
在本申请的二次电池中，负极活性材料的种类并不受到具体的限制，可采用本领域公知的用于二次电池的负极活性材料。作为示例，负极活性材料可包括石墨、软碳、硬碳、中间相碳微球、碳纤维、碳纳米管、硅基材料、锡基材料、钛酸锂中的一种或几 种。硅基材料可包括单质硅、硅氧化物、硅碳复合物、硅氮复合物、硅合金材料中的一种或几种。锡基材料可包括单质锡、锡氧化物、锡合金材料中的一种或几种。本申请并不限定于这些材料，还可以使用其他可被用作二次电池负极活性材料的传统公知的材料。这些负极活性材料可以仅单独使用一种，也可以将两种以上组合使用。
在本申请的二次电池中，负极膜层通常包含负极活性材料、可选的粘结剂、可选的导电剂以及其他可选的助剂。负极膜层通常是将负极浆料涂布在负极集流体上，经干燥、冷压而成的。负极浆料涂通常是将负极活性材料、可选的导电剂、可选地粘结剂、其他可选的助剂分散于溶剂中并搅拌均匀而形成的。溶剂可以是N-甲基吡咯烷酮(NMP)，也可以是去离子水，但不限于此。其中，导电剂以及粘结剂的种类和含量不受具体的限制，可根据实际需求进行选择。作为示例，导电剂可包括超导碳、炭黑(例如乙炔黑、科琴黑等)、碳点、碳纳米管、石墨烯及碳纳米纤维中一种或几种。作为示例，粘结剂可包括丁苯橡胶(SBR)、水溶性不饱和树脂SR-1B、水性丙烯酸树脂(例如，聚丙烯酸PAA、聚甲基丙烯酸PMAA、聚丙烯酸钠PAAS)、聚丙烯酰胺(PAM)、聚乙烯醇(PVA)、海藻酸钠(SA)及羧甲基壳聚糖(CMCS)中的一种或几种。其他可选的助剂可包括增稠剂(例如羧甲基纤维素钠CMC-Na)、PTC热敏电阻材料等。
在本申请的二次电池中，负极膜层可以设置在负极集流体的一侧，也可以同时设置在负极集流体的两侧。例如，负极集流体具有在其自身厚度方向相对的两侧，负极膜层设置在负极集流体相对的两侧中的任意一侧或两侧上。
在本申请的二次电池中，负极集流体的种类不受具体的限制，可根据实际需求进行选择。
本申请的二次电池中，所述负极集流体可采用金属箔片或复合集流体。作为金属箔片的示例，负极集流体可采用铜箔。复合集流体可包括高分子材料基层以及形成于高分子材料基层至少一个表面上的金属材料层。作为示例，金属材料可选自铜、铜合金、镍、镍合金、钛、钛合金、银、银合金中的一种或几种。作为示例，高分子材料基层可选自聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等。
需要说明的是，本申请所给的各负极膜层参数(例如厚度、压实密度等)均指负极集流体单侧的负极膜层的参数。当负极膜层设置在负极集流体的两侧时，其中任意一侧的负极膜层参数满足本申请，即认为落入本申请的保护范围内。且本申请所述的负极膜层厚度、压实密度等范围均是指经冷压压实后并用于组装电池的负极膜层的参数。
另外，本申请的二次电池中，负极极片并不排除除了负极膜层之外的其他附加功能层。例如在某些实施方式中，本申请所述的负极极片还可以包括设置在负极集流体和负极膜层之间的导电底涂层(例如由导电剂和粘结剂组成)。在另外一些实施方式中，本申请所述的负极极片还包括覆盖在负极膜层表面的保护层。
在本申请中，负极活性材料的体积平均粒径Dv50为所述负极活性材料累计体积分布百分数达到50％时所对应的粒径，可采用激光衍射粒度分析法测定。例如参照标准GB/T 19077.1-2016，使用激光粒度分析仪(例如Malvern Master Size 3000)测定。
在本申请中，负极膜层的厚度为本领域公知的含义，可采用本领域已知的方法测 试，例如采用万分尺(例如Mitutoyo293-100型，精度为0.1μm)进行测试。
在本申请中，负极膜层的压实密度为本领域公知的含义，可采用本领域已知的方法测试。负极膜层的压实密度＝负极膜层的面密度/负极膜层的厚度。其中，负极膜层的面密度为本领域公知的含义，可采用本领域已知的方法测试。例如取单面涂布且经冷压后的负极极片(若是双面涂布的负极极片，可先擦拭掉其中一面的负极膜层)，冲切成面积为S1的小圆片，称其重量，记录为M 1；然后将上述称重后的负极极片的负极膜层擦拭掉，称量负极集流体的重量，记录为M 0；负极膜层的面密度＝(负极极片的重量M1-负极集流体的重量M 0)/S 1。
需要说明的是，上述针对负极膜层或负极活性材料的各种参数测试，可以在电池制备过程中取样测试，也可以从制备好的二次电池中取样测试。
当上述测试样品是从制备好的二次电池中取样时，作为示例，可以按如下步骤(1)至步骤(3)进行取样。
(1)将二次电池做放电处理(为了安全起见，一般使电池处于满放状态)；将电池拆卸后取出负极极片，使用碳酸二甲酯(DMC)将负极极片浸泡一定时间(例如2～10小时)；然后将负极极片取出并在一定温度和时间下干燥处理(例如60℃，4h)，干燥后取出负极极片。此时即可以在干燥后的负极极片中取样测试本申请上述的负极膜层相关的各参数。(2)将步骤(1)干燥后的负极极片在一定温度及时间下烘烤(例如400℃，2h)，在烘烤后的负极极片中任选一区域，对负极活性材料取样(可以选用刀片刮粉取样)。(3)将步骤(2)收集到的负极活性材料做过筛处理(例如用200目的筛网过筛)，最终得到可以用于测试本申请上述的各负极活性材料参数的样品。
[正极极片]
本申请的二次电池中，正极极片包括正极集流体以及设置在正极集流体至少一个表面上且包括正极活性材料的正极膜层。例如，正极集流体具有在自身厚度方向相对的两个表面，正极膜层设置在正极集流体的两个相对表面中的任意一者或两者上。
在在一些实施方式中，正极活性材料可以包括锂过渡金属氧化物、橄榄石结构的含锂磷酸盐及其各自的改性化合物中的一种或几种。在本申请的二次电池中，上述各正极活性材料的改性化合物可以是对正极活性材料进行掺杂改性、表面包覆改性、或掺杂同时表面包覆改性。
作为示例，锂过渡金属氧化物可以包括锂钴氧化物、锂镍氧化物、锂锰氧化物、锂镍钴氧化物、锂锰钴氧化物、锂镍锰氧化物、锂镍钴锰氧化物、锂镍钴铝氧化物及其改性化合物中的一种或几种。作为示例，橄榄石结构的含锂磷酸盐可以包括磷酸铁锂、磷酸铁锂与碳的复合材料、磷酸锰锂、磷酸锰锂与碳的复合材料、磷酸锰铁锂、磷酸锰铁锂与碳的复合材料及其改性化合物中的一种或几种。这些正极活性材料可以仅单独使用一种，也可以将两种以上组合使用。
在一些实施方式中，正极活性材料可包括橄榄石结构的含锂磷酸盐及其改性化合物中的一种或几种。在另一些实施方式中，正极活性材料可为橄榄石结构的含锂磷酸盐及其改性化合物中的一种或几种。在正极膜层中使用这些正极活性材料，可以在提升电池的循环性能和存储性能的同时，提升电池的倍率性能。使用这些正极活性材料的电池的工作电压不高，一般≤4.3V，在这个电压范围内第一有机溶剂与第一添加剂搭配使用的 效果更好，因此能进一步提升电池的循环性能和存储性能。
本申请的二次电池中，正极膜层通常包含正极活性材料以及可选的粘结剂和可选的导电剂。正极膜层通常是将正极浆料涂布在正极集流体上，经干燥、冷压而成的。正极浆料通常是将正极活性材料、可选的导电剂、可选的粘结剂以及任意的其他组分分散于溶剂中并搅拌均匀而形成的。溶剂可以是N-甲基吡咯烷酮(NMP)，但不限于此。导电剂以及粘结剂的种类和含量不受具体的限制，可根据实际需求进行选择。作为示例，所述粘结剂可包括聚偏氟乙烯(PVDF)、聚四氟乙烯(PTFE)、偏氟乙烯-四氟乙烯-丙烯三元共聚物、偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、四氟乙烯-六氟丙烯共聚物、含氟丙烯酸酯树脂中的一种或几种。作为示例，所述导电剂可包括超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯、碳纳米纤维中的一种或几种。
本申请的二次电池中，所述正极集流体可采用金属箔片或复合集流体。作为金属箔片的示例，正极集流体可采用铝箔。复合集流体可包括高分子材料基层以及形成于高分子材料基层至少一个表面上的金属材料层。作为示例，金属材料可选自铝、铝合金、镍、镍合金、钛、钛合金、银、银合金中的一种或几种。作为示例，高分子材料基层可选自聚丙烯、聚对苯二甲酸乙二醇酯、聚对苯二甲酸丁二醇酯、聚苯乙烯、聚乙烯等。
[隔离膜]
本申请的二次电池还包括隔离膜。隔离膜设置在正极极片和负极极片之间，起到隔离的作用。隔离膜的种类并不受到具体的限制，可以选用任意公知的具有良好的化学稳定性和机械稳定性的多孔结构隔离膜。在一些实施方式中，隔离膜的材质可以选自玻璃纤维、无纺布、聚乙烯、聚丙烯、聚偏氟乙烯中的一种或几种，但不仅限于这些。隔离膜可以是单层薄膜，也可以是多层复合薄膜。隔离膜为多层复合薄膜时，各层的材料相同或不同。在一些实施例方式中，隔离膜上还可以设置陶瓷涂层、金属氧化物涂层。
在一些实施方式中，正极极片、负极极片和隔离膜可通过卷绕工艺或叠片工艺制成电极组件。
在一些实施方式中，二次电池可包括外包装。该外包装可用于封装上述电极组件及电解液。
在一些实施方式中，二次电池的外包装可以是硬壳，例如硬塑料壳、铝壳、钢壳等。二次电池的外包装也可以是软包，例如袋式软包。软包的材质可以是塑料，如聚丙烯、聚对苯二甲酸丁二醇酯(PBT)、聚丁二酸丁二醇酯(PBS)等中的一种或几种。
本申请对二次电池的形状没有特别的限制，其可以是圆柱形、方形或其他任意的形状。如图1是作为一个示例的方形结构的二次电池5。
在一些实施方式中，参照图2，外包装可包括壳体51和盖板53。其中，壳体51可包括底板和连接于底板上的侧板，底板和侧板围合形成容纳腔。壳体51具有与容纳腔连通的开口，盖板53用于盖设所述开口，以封闭所述容纳腔。正极极片、负极极片和隔离膜可经卷绕工艺或叠片工艺形成电极组件52。电极组件52封装于所述容纳腔。电解液浸润于电极组件52中。二次电池5所含电极组件52的数量可以为一个或几个，可根据需求来调节。
在一些实施方式中，二次电池可以组装成电池模块，电池模块所含二次电池的数量可以为多个，具体数量可根据电池模块的应用和容量来调节。
图3是作为一个示例的电池模块4。参照图3，在电池模块4中，多个二次电池5可以是沿电池模块4的长度方向依次排列设置。当然，也可以按照其他任意的方式进行排布。进一步可以通过紧固件将该多个二次电池5进行固定。
可选地，电池模块4还可以包括具有容纳空间的外壳，多个二次电池5容纳于该容纳空间。
在一些实施方式中，上述电池模块还可以组装成电池包，电池包所含电池模块的数量可以根据电池包的应用和容量进行调节。
图4和图5是作为一个示例的电池包1。参照图4和图5，在电池包1中可以包括电池箱和设置于电池箱中的多个电池模块4。电池箱包括上箱体2和下箱体3，上箱体2用于盖设下箱体3，并形成用于容纳电池模块4的封闭空间。多个电池模块4可以按照任意的方式排布于电池箱中。
用电装置
本申请第二方面提供一种用电装置，所述用电装置包括本申请的二次电池、电池模块、或电池包中的至少一种。所述二次电池、电池模块或电池包可以用作所述用电装置的电源，也可以用作所述用电装置的能量存储单元。所述用电装置可以但不限于是移动设备(例如手机、笔记本电脑等)、电动车辆(例如纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板车、电动高尔夫球车、电动卡车等)、电气列车、船舶及卫星、储能系统等。
所述用电装置可以根据其使用需求来选择二次电池、电池模块或电池包。
图6是作为一个示例的用电装置。该用电装置为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了满足该用电装置对高功率和高能量密度的需求，可以采用电池包或电池模块。
作为另一个示例的用电装置可以是手机、平板电脑、笔记本电脑等。该用电装置通常要求轻薄化，可以采用二次电池作为电源。
实施例
下述实施例更具体地描述了本申请公开的内容，这些实施例仅仅用于阐述性说明，因为在本申请公开内容的范围内进行各种修改和变化对本领域技术人员来说是明显的。除非另有声明，以下实施例中所报道的所有份、百分比、和比值都是基于质量计，而且实施例中使用的所有试剂都可商购获得或是按照常规方法进行合成获得，并且可直接使用而无需进一步处理，以及实施例中使用的仪器均可商购获得。
以下各实施例和对比例中，负极极片所采用的人造石墨、导电剂乙炔黑、粘结剂丁苯橡胶(SBR)、增稠剂羧甲基纤维素钠(CMC-Na)均可以通过商购获得。正极极片所采用的正极活性材料磷酸铁锂、粘结剂聚偏氟乙烯(PVDF)、导电剂乙炔黑、溶剂N-甲基吡咯烷酮(NMP)均可以通过商购获得。电解液所采用的LiPF6、第一有机溶剂、第二有机溶剂、第一添加剂、第二添加剂、硫酸乙烯酯(DTD)均可以通过商购获得。隔离膜所采用的聚丙烯膜可以通过商购获得。
实施例1
负极极片的制备
将负极活性材料人造石墨、导电剂乙炔黑、粘结剂丁苯橡胶(SBR)、增稠剂羧 甲基纤维素钠(CMC-Na)按照质量比为95∶2∶2∶1溶于溶剂去离子水中，充分搅拌混合均匀后制备成负极浆料；将负极浆料均匀涂覆在负极集流体铜箔上，之后经过烘干、冷压、分切，得到负极极片。
正极极片的制备
将正极活性材料磷酸铁锂、粘结剂聚偏氟乙烯(PVDF)、导电剂乙炔黑按照质量比为97∶2∶1溶于溶剂N-甲基吡咯烷酮(NMP)中，充分搅拌混合均匀后制备成正极浆料；将正极浆料均匀涂覆在正极集流体铝箔上，之后经过烘干、冷压、分切，得到正极极片。
电解液的制备
在氩气气氛手套箱中(H 2O含量＜0.1ppm，O 2含量＜0.1ppm)，将化合物1-2、碳酸乙烯酯(EC)、碳酸甲乙酯(EMC)按照质量比为30∶30∶40混合均匀，制备成有机溶剂；将一定量的LiPF6和一定量的化合物2-4溶于上述有机溶剂中，搅拌均匀，得到电解液。其中，化合物2-4在电解液中的质量百分数为2％，电解液的电导率为13.5mS/cm。
隔离膜
采用聚丙烯膜作为隔离膜。
二次电池的制备
将正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正极极片和负极极片之间起到隔离的作用，然后卷绕得到电极组件；将电极组件置于外包装中，干燥后注入电解液；之后经过化成、静置等工艺，得到二次电池。二次电池的长度为194mm、宽度为70mm、高度为112mm。
实施例2～26及对比例1～3
实施例2～26及对比例1～3的制备方法与实施例1类似，不同的是：调整了电解液的相关参数，具体电解液参数详见表1。其中，对比例3的电解液使用的第一添加剂为化合物2-9。
Figure PCTCN2021109905-appb-000015
测试部分
(1)电池的快速充电性能测试
在25℃下，将上述各实施例和对比例的电池以0.33C(其中，1C表示1h内完全放掉电池理论容量对应的电流值)的电流进行第一次充电和放电。具体步骤包括：将电池以0.33C恒流充电至电压为3.65V，之后以3.65V恒压充电至电流≤0.05C；将电池静置5min，以0.33C恒流放电至电压为2.5V，记录电池实际放电容量为C 0。
将电池依次以不同的充电倍率，0.5C 0、0.8C 0、1.2C 0、1.5C 0、2.0C 0、2.5C 0、3.0C 0、4.0C 0、5.0C 0，恒流充电至电池充电截止电压3.65V或者负极电位降为0V(以先达到者为准)，每次充电完成后需再以0.33C 0放电至电池放电截止电压2.5V。记录不同充电倍率下将电池充电至10％SOC、20％SOC、30％SOC、40％SOC、50％SOC、60％SOC、70％SOC、80％SOC(SOC表示电池的荷电状态State of Charge)时所对应的负极电位。
绘制出不同荷电状态下的充电倍率-负极电位曲线，将其线性拟合得出不同荷电状态下负极电位为0V时所对应的充电倍率，该充电倍率即为该荷电状态下的充电窗口。不同荷电状态下的充电窗口分别记为C 10％SOC、C 20％SOC、C 30％SOC、C 40％SOC、C 50％SOC、C 60％SOC、C 70％SOC、C 80％SOC。根据公式(60/C 20％SOC+60/C 30％SOC+60/C 40％SOC+60/C 50％SOC+60/C 60％SOC+60/C 70％SOC+60/C 80％SOC)×10％，计算得到电池从10％SOC充电至80％SOC的充电时间T。充电时间T越短，表示电池的快速充电性能越优秀。
(2)电池的60℃循环性能测试
在60℃下，将上述各实施例和对比例的电池以1C恒流充电至电压为3.65V，之后以3.65V恒压充电至电流≤0.05C，然后将电池以1C恒流放电至电压为2.5V，此为一个充放电过程，此时的放电容量记为电池首次循环的放电容量。如此反复进行充电和放电循环，计算电池循环500次后的容量保持率。
电池60℃循环500次后的容量保持率(％)＝(电池第500次循环的放电容量/电池首次循环的放电容量)×100％。
(3)电池的60℃存储产气量测试
在25℃下，将上述各实施例和对比例的电池以0.33C恒流充电至电压为3.65V，之后以3.65V恒压充电至电流≤0.05C，然后将电池以0.33C恒流放电至电压为2.5V，记录电池实际放电容量为C 0。在25℃下，将电池继续以0.33C 0恒流充电至电压为3.65V，之后以3.65V恒压充电至电流≤0.05C 0，此时电池为满充状态，测量电池的体积记为电池存储前的体积。将满充状态的电池置于60℃的恒温箱中存储，存储30天后将电池从恒温箱中取出并测量体积。
电池60℃存储30天的产气量(ml/Ah)＝(电池存储30天后的体积-电池存储前的体积)/电池额定容量。
(4)电池的60℃存储容量保持率测试
在25℃下，将上述各实施例和对比例的电池以0.33C恒流充电至电压为3.65V，之后以3.65V恒压充电至电流≤0.05C；将电池以0.33C恒流放电至电压为2.5V，记录电池实际放电容量为C 0。在25℃下，将电池继续以0.33C 0恒流充电至电压为3.65V，之后以3.65V恒压充电至电流≤0.05C 0，此时电池为满充状态。将满充状态的电池置于60℃的恒温箱中存储60天，将电池取出进行容量测试。
电池60℃存储60天后的容量保持率＝(电池存储60天后的放电容量/电池实际放电容量C 0)×100％。
实施例1～26及对比例1～3的电解液参数详见表1，测试结果详见表2。
Figure PCTCN2021109905-appb-000016
表2
Figure PCTCN2021109905-appb-000017
由表2的测试结果可知，在电解液中使用第一有机溶剂可以提高电池的快速充电性能，但由于第一有机溶剂与负极兼容性差，会恶化电池的循环性能和存储性能，尤其对电池高温环境下的性能恶化更明显。从对比例2与对比例1的测试结果可以发现，在电解液中添加适量的DTD，对电池循环性能和存储性能的改善效果并不理想。这主要是由于，DTD会在正极活性材料和负极活性材料表面均形成稳定的界面膜，抑制负极与第一有机溶剂发生持续反应；但DTD在形成界面膜的过程中也会有气体产生，持续产生的气体会在正极极片、负极极片与隔离膜的界面富集而形成宏观上的气泡，这些气泡会阻断锂离子的传输。
由表2的测试结果可知，实施例1～26的电池通过使用第一添加剂代替DTD，能显著改善电池的循环性能和存储性能，尤其是能显著改善电池的高温循环性能和高温存储性能；同时，实施例1～26的电池仍保持良好的快速充电性能。
从对比例3与实施例1～26的测试结果对比中可以看出，实施例1～26的电池具有 更优异的循环性能和存储性能。
从实施例1～2的测试结果对比中可以看出，第二有机溶剂的种类改变，电池的快速充电性能、循环性能和存储性能也会发生变化，但都在合理的范围内，不会产生过大的变化量。因此，本申请对第二有机溶剂的种类没有特别的限制。
从实施例1、实施例3～8的测试结果对比中可以看出，第一有机溶剂的含量增加，电池的充电时间T降低、高温存储产气量增加、高温存储容量保持率和高温循环容量保持率均降低。这主要是由于，第一有机溶剂含量增加后，α-H数量增加，电池内部活性锂损失增加，因此，电池高温存储后的容量保持率降低；并且，第一有机溶剂的耐氧化能力较差，在高荷电状态存储时容易发生氧化分解，因此，电池高温存储产气量也会增加。
从实施例1、实施例9～15的测试结果对比中可以看出，第一添加剂的种类改变，电池的快速充电性能、循环性能和存储性能也会发生变化，但都在合理的范围内，不会产生过大的变化量。
从实施例1、实施例16～18的测试结果对比中可以看出，第一有机溶剂的种类改变，电池的快速充电性能、循环性能和存储性能也会发生变化，但都在合理的范围内，不会产生过大的变化量。
从实施例19～26的测试结果对比中可以看出，第一添加剂的含量增加，电池高温存储产气量降低，电池充电时间先降低后增加，电池高温存储容量保持率和高温循环容量保持率先增加后降低。可能的原因在于，第一添加剂具有较高的还原电位，能优先于第一有机溶剂在负极活性材料表面形成致密、稳定的含硫有机物界面膜，抑制第一有机溶剂与负极持续发生反应，因此电池高温存储产气量会降低。但是第一添加剂具有环状结构，含量增加后负极活性材料表面成膜厚度增加、成膜阻抗会略有增加，影响了锂离子在负极界面的传输速度，因此电池的充电时间会有一定程度的增加，电池高温存储容量保持率和高温循环容量保持率会有一定程度的降低。
实施例27
负极极片的制备
将负极活性材料人造石墨(体积平均粒径Dv50为17μm)、导电剂乙炔黑、粘结剂丁苯橡胶(SBR)、增稠剂羧甲基纤维素钠(CMC-Na)按照质量比为95∶2∶2∶1溶于溶剂去离子水中，充分搅拌混合均匀后制备成负极浆料；将负极浆料均匀涂覆在负极集流体铜箔的两个表面上，之后经过烘干、冷压、分切，得到负极极片。负极浆料干燥后形成负极膜层，负极膜层单面的厚度为60μm，负极膜层的压实密度为1.65g/cm 3。
正极极片的制备
将正极活性材料磷酸铁锂、粘结剂聚偏氟乙烯(PVDF)、导电剂乙炔黑按照质量比为97∶2∶1溶于溶剂N-甲基吡咯烷酮(NMP)中，充分搅拌混合均匀后制备成正极浆料；将正极浆料均匀涂覆在正极集流体铝箔上，之后经过烘干、冷压、分切，得到正极极片。
电解液的制备
在氩气气氛手套箱中(H 2O含量＜0.1ppm，O 2含量＜0.1ppm)，将化合物1-2、碳酸乙烯酯(EC)、碳酸甲乙酯(EMC)按照质量比为30∶30∶40混合均匀，制备成有机溶 剂；将一定量的LiPF 6和一定量的第一添加剂化合物2-4溶于上述有机溶剂中，搅拌均匀，得到电解液。其中，化合物2-4在电解液中的质量百分数为2％，电解液的电导率为13.5mS/cm。
隔离膜
采用聚丙烯膜作为隔离膜。
二次电池的制备
将正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正极极片和负极极片之间起到隔离的作用，然后卷绕得到电极组件；将电极组件置于外包装中，干燥后注入电解液；之后经过化成、静置等工艺，得到二次电池。二次电池的长度为194mm、宽度为70mm、高度为112mm。
实施例28～37
实施例28～37的制备方法与实施例27类似，不同的是：调整了负极极片的相关参数，具体参数详见表3。
测试部分
(1)电池的体积能量密度测试
在25℃下，将上述各实施例和对比例的电池以0.33C恒流充电至电压为3.65V，之后以3.65V恒压充电至电流≤0.05C；将电池以0.33C恒流放电至电压为2.5V，得到放电能量Q。利用游标卡尺测量电池外壳的长度、宽度、高度，计算得到电池的体积V。
电池的体积能量密度＝放电能量Q/电池的体积V，体积能量密度的单位为Wh/L。
实施例27～37的负极极片参数和电池性能测试结果详见表3。
表3
Figure PCTCN2021109905-appb-000018
从表3的测试结果可以看出，随着单面负极膜层的厚度H的增加，电池的体积能量密度随之增加，但是充电时间T会延长。在单面负极膜层的厚度H一定的情况下，随着负极活性材料的体积平均粒径Dv50减小，活性离子的扩散路径会缩短，充电时间T会减小；但是，负极活性材料的体积平均粒径Dv50也不宜过小，这会增加负极膜层与电解液的接触面积，电解液在负极活性材料颗粒表面的副反应增加，进而影响电池的循环性 能和存储性能。因此，限定单面负极膜层的厚度与负极活性材料的体积平均粒径Dv50的比值H/Dv50在合适的范围内，再搭配本申请的电解液，能使电池兼具良好的快速充电性能、长使用寿命和高能量密度。
需要说明的是，本申请不限定于上述实施方式。上述实施方式仅为示例，在本申请的技术方案范围内具有与技术思想实质相同的构成、发挥相同作用效果的实施方式均包含在本申请的技术范围内。此外，在不脱离本申请主旨的范围内，对实施方式施加本领域技术人员能够想到的各种变形、将实施方式中的一部分构成要素加以组合而构筑的其它方式也包含在本申请的范围内。

Claims (22)

  1. 一种电解液，包括有机溶剂以及添加剂，
    其中，所述有机溶剂包括式1所示的第一有机溶剂，
    Figure PCTCN2021109905-appb-100001
    在式1中，R 1和R 2分别独立地为C1～C3烷基、C1～C3卤代烷基中的一种；
    所述添加剂包括第一添加剂，所述第一添加剂选自式2A、式2B所示化合物中的一种或几种，
    Figure PCTCN2021109905-appb-100002
    在式2A中，R 21、R 22、R 23、R 24分别独立地为单键、亚甲基中的一种，
    在式2B中，R 31、R 32、R 33、R 34分别独立地为单键、亚甲基中的一种，
    R 4为单键、-O-、C1～C3亚烷基、C1～C3卤代亚烷基、C1～C3氧杂亚烷基中的一种。
  2. 根据权利要求1所述的电解液，其中，
    R 1和R 2分别独立地为甲基、乙基、丙基、氟代甲基、氟代乙基、氟代丙基中的一种；和/或
    R 21、R 22、R 23、R 24不同时为单键，可选地，R 21、R 22中的一个或两个为亚甲基，R 23、R 24中的一个或两个为亚甲基；和/或
    R 31、R 32、R 33、R 34分别独立地为单键、亚甲基中的一种，且R 31、R 32、R 33、R 34不同时为单键；和/或
    R 4为单键、-O-、亚甲基、亚乙基、亚丙基、氟代亚甲基、氟代亚乙基、氟代亚丙基、亚甲氧基、亚乙氧基、亚丙氧基中的一种，可选地，R 4为单键、亚甲基、亚乙基、亚丙基中的一种。
  3. 根据权利要求1～2任一项所述的电解液，其中，R 31、R 32、R 33、R 34、R 4还满足下述(1)～(6)中的一个：
    (1)R 4为单键，R 31、R 32中的一个或两个为亚甲基，其余为单键，
    (2)R 4为单键，R 33、R 34中的一个或两个为亚甲基，其余为单键，
    (3)R 4为单键，R 31、R 32中的一个为亚甲基，R 33、R 34中的一个为亚甲基，其余为单键，
    (4)R 4为单键，R 31、R 32均为亚甲基，R 33、R 34中的一个为亚甲基，其余为单键，
    (5)R 4为单键，R 33、R 34均为亚甲基，R 31、R 32中的一个为亚甲基，其余为单键，
    (6)R 4为单键，R 31、R 32、R 33、R 34均为亚甲基。
  4. 根据权利要求1～3任一项所述的电解液，其中，第一有机溶剂选自如下化合物中的一种或几种：
    Figure PCTCN2021109905-appb-100003
    可选地，第一有机溶剂选自如下化合物中的一种或两种：
    Figure PCTCN2021109905-appb-100004
  5. 根据权利要求1～4任一项所述的电解液，其中，第一添加剂选自如下化合物中的一种或几种：
    Figure PCTCN2021109905-appb-100005
    可选地，第一添加剂选自如下化合物中的一种或几种：
    Figure PCTCN2021109905-appb-100006
  6. 根据权利要求1～5任一项所述的电解液，其中，基于所述有机溶剂的总质量，第一有机溶剂的质量百分数为w1，w1的范围为20％～80％，可选地为30％～70％。
  7. 根据权利要求1～6任一项所述的电解液，其中，基于所述电解液的总质量，第一添加剂的质量百分数为w2，w2的范围为0.1％～10％，可选地为0.5％～5％。
  8. 根据权利要求1～7任一项所述的电解液，其中，所述添加剂还包括第二添加剂，所述第二添加剂包括含有不饱和键的环状碳酸酯化合物、卤素取代的环状碳酸酯化合物、硫酸酯化合物、亚硫酸酯化合物、磺酸内酯化合物、二磺酸化合物、腈化合物、芳 香化合物、异氰酸酯化合物、磷腈化合物、环状酸酐化合物、亚磷酸酯化合物、磷酸酯化合物、硼酸酯化合物、羧酸酯化合物中的一种或几种，
    可选地，所述第二添加剂包括如下化合物中的一种或两种：
    Figure PCTCN2021109905-appb-100007
  9. 根据权利要求1～8任一项所述的电解液，其中，基于所述电解液的总质量，第二添加剂的质量百分数为w3，w3的范围为≤10％，可选地≤5％。
  10. 根据权利要求1～9任一项所述的电解液，其中，所述有机溶剂还包括第二有机溶剂，所述第二有机溶剂包括环状碳酸酯化合物、链状碳酸酯化合物中的一种或几种，可选地包括环状碳酸酯化合物、或包括环状碳酸酯化合物与链状碳酸酯化合物的组合。
  11. 根据权利要求1～10任一项所述的电解液，其中，所述有机溶剂还包括第二有机溶剂，所述第二有机溶剂包括碳酸乙烯酯、碳酸丙烯酯、碳酸1，2-丁烯酯、碳酸二甲酯、碳酸甲乙酯、碳酸二乙酯、碳酸二丙酯、碳酸甲丙酯、碳酸乙丙酯中的一种或几种。
  12. 根据权利要求1～11所述的电解液，其中，基于所述有机溶剂的总质量，环状碳酸酯化合物的质量百分数为w4，w4的范围为20％～80％，可选地为20％～50％。
  13. 根据权利要求1～12任一项所述的电解液，其中，所述电解液还包括锂盐，所述锂盐包括LiN(C xF 2x+1SO 2)(C yF 2y+1SO 2)、LiPF 6、LiBF 4、LiBOB、LiDFOB、LiPO 2F 2、LiDFOP、LiTFOP、LiAsF 6、Li(FSO 2) 2N、LiCF 3SO 3以及LiClO 4中的一种或几种，其中，x、y为正整数。
  14. 根据权利要求1～13任一项所述的电解液，其中，所述电解液的电导率满足≥12mS/cm，可选地满足≥13mS/cm，更具体地，所述电解液的电导率为12mS/cm～24mS/cm或13mS/cm～20mS/cm。
  15. 一种二次电池，包括根据权利要求1～14任一项所述的电解液。
  16. 根据权利要求15所述的二次电池，其中，所述二次电池包括负极极片，所述负极极片包括负极集流体以及设置在负极集流体至少一个表面上且包括负极活性材料的负极膜层，单面负极膜层的厚度H与负极活性材料的体积平均粒径Dv50的比值H/Dv50满足≥3，可选地满足4≤H/Dv50≤9。
  17. 根据权利要求15～16任一项所述的二次电池，其中，
    单面负极膜层的厚度H满足≥60μm，可选地满足≥65μm；和/或
    负极活性材料的体积平均粒径Dv50满足≤18μm，可选地满足14μm≤Dv50≤18μm。
  18. 根据权利要求15～17任一项所述的二次电池，其中，负极膜层的压实密度为1.4g/cm 3～1.85g/cm 3，可选地为1.6g/cm 3～1.8g/cm 3。
  19. 根据权利要求15～18任一项所述的二次电池，其中，所述二次电池包括正极极片，所述正极极片包括正极活性材料，所述正极活性材料包括锂过渡金属氧化物、橄榄石结构的含锂磷酸盐及其各自的改性化合物中的一种或几种，
    可选地，橄榄石结构的含锂磷酸盐包括磷酸铁锂、磷酸铁锂与碳的复合材料、磷酸锰锂、磷酸锰锂与碳的复合材料、磷酸锰铁锂、磷酸锰铁锂与碳的复合材料及其改性化合物中的一种或几种。
  20. 一种电池模块，包括根据权利要求15～19任一项所述的二次电池。
  21. 一种电池包，包括根据权利要求15～19任一项所述的二次电池、根据权利要求20所述的电池模块中的一种。
  22. 一种用电装置，包括根据权利要求15～19任一项所述的二次电池、根据权利要求20所述的电池模块、根据权利要求21所述的电池包中的至少一种。
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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117543071A (zh) * 2023-09-28 2024-02-09 深圳市贝特瑞新能源技术研究院有限公司 半固态电池及其制造方法和检测方法
WO2024197714A1 (zh) * 2023-03-30 2024-10-03 宁德时代新能源科技股份有限公司 钠离子电池用电解液、钠离子电池单体和二次电池
CN119823092A (zh) * 2025-03-14 2025-04-15 江苏华盛锂电材料股份有限公司 硫酸乙烯酯类化合物、合成方法及其在二次电池中的应用
WO2025086283A1 (zh) * 2023-10-27 2025-05-01 宁德新能源科技有限公司 一种二次电池和电子装置
WO2025197263A1 (ja) * 2024-03-21 2025-09-25 Ｍｕアイオニックソリューションズ株式会社 電解液及びその製造方法、電池及びその製造方法、並びに該電池を搭載する車両
CN121192252A (zh) * 2025-11-24 2025-12-23 华南理工大学 一种非水电解液及锂离子电池

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024205203A1 (ko) * 2023-03-26 2024-10-03 삼성에스디아이주식회사 전해질 및 이를 포함하는 리튬전지
KR102869523B1 (ko) * 2023-03-26 2025-10-14 삼성에스디아이 주식회사 전해질 및 이를 포함하는 리튬전지
CN117393858A (zh) * 2023-12-08 2024-01-12 宁德时代新能源科技股份有限公司 锂二次电池、其制备方法和用电装置
KR20260021816A (ko) * 2024-06-28 2026-02-13 컨템포러리 엠퍼렉스 테크놀로지 씨오., 리미티드 이차 전지 및 전기 장치
WO2026020389A1 (zh) * 2024-07-24 2026-01-29 宁德时代新能源科技股份有限公司 电池单体、电池装置、用电装置

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107086324A (zh) * 2016-02-12 2017-08-22 三星Sdi株式会社 有机电解液和包含该有机电解液的锂电池
WO2018097523A1 (ko) * 2016-11-23 2018-05-31 에스케이케미칼주식회사 이차전지용 전해액 및 이를 포함하는 이차전지
KR20180119842A (ko) * 2017-04-26 2018-11-05 에스케이케미칼 주식회사 이차전지용 전해액 및 이를 포함하는 이차전지
US20190067741A1 (en) * 2015-06-08 2019-02-28 Sk Innovation Co., Ltd. Electrolyte for Lithium Secondary Battery and Lithium Secondary Battery Containing the Same
CN109950621A (zh) * 2017-12-21 2019-06-28 深圳新宙邦科技股份有限公司 一种锂离子电池非水电解液及锂离子电池
CN110931869A (zh) * 2019-12-02 2020-03-27 广州天赐高新材料股份有限公司 一种高温型锂二次电池电解液及电池
CN111293357A (zh) * 2018-12-10 2020-06-16 张家港市国泰华荣化工新材料有限公司 一种非水电解液及其应用

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101286573A (zh) * 2007-04-09 2008-10-15 比亚迪股份有限公司 一种电解液及含有该电解液的锂离子二次电池
KR20150079586A (ko) * 2012-10-22 2015-07-08 아사히 가라스 가부시키가이샤 이차 전지용 비수 전해액 및 리튬 이온 이차 전지
JP6631404B2 (ja) * 2016-05-19 2020-01-15 株式会社Ｇｓユアサ 非水電解液二次電池用非水電解液、非水電解液二次電池、及び非水電解液二次電池の製造方法
JP2018092778A (ja) * 2016-12-02 2018-06-14 日立化成株式会社 リチウムイオン二次電池
JP7128422B2 (ja) * 2017-04-10 2022-08-31 セントラル硝子株式会社 ホスホリルイミド塩の製造方法、該塩を含む非水電解液の製造方法及び非水二次電池の製造方法
CN107171022B (zh) * 2017-06-14 2019-10-29 厦门首能科技有限公司 一种锂离子电解液及其锂离子电池
EP3662532A4 (en) * 2017-07-31 2021-09-08 Tesla Motors Canada ULC NEW BATTERY SYSTEMS BASED ON LITHIUM DIFLUORPHOSPHATE
CN111902990A (zh) * 2018-03-29 2020-11-06 松下知识产权经营株式会社 电化学器件
CN110660963B (zh) * 2018-12-29 2021-04-27 宁德时代新能源科技股份有限公司 一种电极极片和电化学装置
US11462769B2 (en) * 2019-12-03 2022-10-04 Enevate Corporation Silicon-based energy storage devices with electrolyte containing a benzoyl peroxide based compound
CN118919728A (zh) * 2019-12-25 2024-11-08 宁德新能源科技有限公司 电化学装置及包含其的电子装置
JP7509869B2 (ja) * 2019-12-25 2024-07-02 寧徳新能源科技有限公司 電気化学装置及びそれを含む電子装置
JP7156263B2 (ja) * 2019-12-25 2022-10-19 トヨタ自動車株式会社 全固体電池および全固体電池の製造方法
KR102887987B1 (ko) * 2020-01-20 2025-11-19 닝더 엠프렉스 테크놀로지 리미티드 전해액 및 이를 사용하는 전기화학 디바이스

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20190067741A1 (en) * 2015-06-08 2019-02-28 Sk Innovation Co., Ltd. Electrolyte for Lithium Secondary Battery and Lithium Secondary Battery Containing the Same
CN107086324A (zh) * 2016-02-12 2017-08-22 三星Sdi株式会社 有机电解液和包含该有机电解液的锂电池
WO2018097523A1 (ko) * 2016-11-23 2018-05-31 에스케이케미칼주식회사 이차전지용 전해액 및 이를 포함하는 이차전지
KR20180119842A (ko) * 2017-04-26 2018-11-05 에스케이케미칼 주식회사 이차전지용 전해액 및 이를 포함하는 이차전지
CN109950621A (zh) * 2017-12-21 2019-06-28 深圳新宙邦科技股份有限公司 一种锂离子电池非水电解液及锂离子电池
CN111293357A (zh) * 2018-12-10 2020-06-16 张家港市国泰华荣化工新材料有限公司 一种非水电解液及其应用
CN110931869A (zh) * 2019-12-02 2020-03-27 广州天赐高新材料股份有限公司 一种高温型锂二次电池电解液及电池

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP4160773A4 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024197714A1 (zh) * 2023-03-30 2024-10-03 宁德时代新能源科技股份有限公司 钠离子电池用电解液、钠离子电池单体和二次电池
CN117543071A (zh) * 2023-09-28 2024-02-09 深圳市贝特瑞新能源技术研究院有限公司 半固态电池及其制造方法和检测方法
WO2025086283A1 (zh) * 2023-10-27 2025-05-01 宁德新能源科技有限公司 一种二次电池和电子装置
WO2025197263A1 (ja) * 2024-03-21 2025-09-25 Ｍｕアイオニックソリューションズ株式会社 電解液及びその製造方法、電池及びその製造方法、並びに該電池を搭載する車両
CN119823092A (zh) * 2025-03-14 2025-04-15 江苏华盛锂电材料股份有限公司 硫酸乙烯酯类化合物、合成方法及其在二次电池中的应用
CN121192252A (zh) * 2025-11-24 2025-12-23 华南理工大学 一种非水电解液及锂离子电池

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CN116349050B (zh) 2026-03-03
EP4160773A1 (en) 2023-04-05
PL4160773T3 (pl) 2026-03-30
US20230318042A1 (en) 2023-10-05
EP4734215A2 (en) 2026-04-29
KR102889485B1 (ko) 2025-11-21
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EP4160773A4 (en) 2023-11-08
JP7653505B2 (ja) 2025-03-28

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