WO2024007242A1 - 粘结剂、粘结剂组合物、制备方法、负极浆料、负极极片、二次电池、电池模块、电池包及用电装置 - Google Patents

粘结剂、粘结剂组合物、制备方法、负极浆料、负极极片、二次电池、电池模块、电池包及用电装置 Download PDF

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Publication number
WO2024007242A1
WO2024007242A1 PCT/CN2022/104329 CN2022104329W WO2024007242A1 WO 2024007242 A1 WO2024007242 A1 WO 2024007242A1 CN 2022104329 W CN2022104329 W CN 2022104329W WO 2024007242 A1 WO2024007242 A1 WO 2024007242A1
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WIPO (PCT)
Prior art keywords
binder
negative electrode
monomer
battery
viscosity
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
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PCT/CN2022/104329
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English (en)
French (fr)
Inventor
陈淑华
刘会会
王兴辉
张文梦
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Contemporary Amperex Technology Co Ltd
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Contemporary Amperex Technology Co Ltd
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Publication date
Application filed by Contemporary Amperex Technology Co Ltd filed Critical Contemporary Amperex Technology Co Ltd
Priority to KR1020247023669A priority Critical patent/KR20240125609A/ko
Priority to PCT/CN2022/104329 priority patent/WO2024007242A1/zh
Priority to EP22949827.4A priority patent/EP4450580A4/en
Priority to CN202280067777.2A priority patent/CN118176271A/zh
Priority to JP2024541725A priority patent/JP2025502184A/ja
Publication of WO2024007242A1 publication Critical patent/WO2024007242A1/zh
Priority to US18/775,460 priority patent/US20240372100A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621—Binders
    • H01M4/622—Binders being polymers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/04—Acids; Metal salts or ammonium salts thereof
    • C08F220/06—Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/10—Esters
    • C08F220/12—Esters of monohydric alcohols or phenols
    • C08F220/14—Methyl esters, e.g. methyl (meth)acrylate
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F236/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds
    • C08F236/02—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds
    • C08F236/04—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds conjugated
    • C08F236/10—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds conjugated with vinyl-aromatic monomers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F257/00—Macromolecular compounds obtained by polymerising monomers on to polymers of aromatic monomers as defined in group C08F12/00
    • C08F257/02—Macromolecular compounds obtained by polymerising monomers on to polymers of aromatic monomers as defined in group C08F12/00 on to polymers of styrene or alkyl-substituted styrenes
    • 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
    • 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
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F212/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring
    • C08F212/02—Monomers containing only one unsaturated aliphatic radical
    • C08F212/04—Monomers containing only one unsaturated aliphatic radical containing one ring
    • C08F212/06—Hydrocarbons
    • C08F212/08—Styrene
    • 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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • 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

  • This application belongs to the technical field of secondary batteries, and specifically relates to a binder, binder composition, preparation method, negative electrode slurry, negative electrode sheet, secondary battery, battery module, battery pack and electrical device.
  • Secondary batteries are widely used in various consumer electronics and electric vehicles due to their outstanding characteristics such as light weight, no pollution, and no memory effect. With the continuous development of the new energy industry, customers have put forward higher demand for secondary batteries.
  • the binders styrene-butadiene rubber and sodium carboxymethyl cellulose are often used to prepare negative electrode sheets, which cannot take into account the processing performance of the negative electrode sheet and the dynamic performance of the battery core corresponding to the negative electrode sheet. Therefore, the traditional binders used for negative electrode plates need to be improved.
  • this application provides a binder, a binder composition, a preparation method, a negative electrode slurry, a negative electrode sheet, a secondary battery, a battery module, a battery pack and an electrical device, aiming to It simultaneously meets the processing performance of the negative electrode piece and the dynamic performance of the battery core corresponding to the negative electrode piece.
  • an adhesive including:
  • the glass transition temperature of the core material is -50°C to 0°C;
  • the shell material is located on at least part of the surface of the core material, and the glass transition temperature of the shell material is 60°C to 100°C.
  • this application at least includes the following beneficial effects:
  • the shell material is located on at least part of the surface of the core material.
  • the core material is a soft material with a lower glass transition temperature
  • the shell material is a hard material with a higher glass transition temperature.
  • the binder It is a core-shell structure with a soft inside and a hard outside; the soft core material facilitates cold pressing of the negative electrode sheet, helps reduce the cold pressing pressure, increases the compaction window of the negative active material, and provides better adhesion, thereby reducing the
  • the amount of binder used the smaller amount of binder reduces the coating of the surface of the negative electrode active material; the relatively hard shell material will not undergo excessive deformation after the negative electrode piece is cold pressed, reducing the binder's impact on the negative electrode.
  • the coating area of the active material effectively reduces the impedance when lithium ions are inserted and extracted, and improves the dynamic performance of the battery cell corresponding to the negative electrode piece.
  • the DC internal resistance (DCR) of the battery core is reduced by 5% to 12%, and the charging window is slightly increased.
  • the adhesive in this application has The bonding force is increased by more than 20%, there is no peeling or powder loss, and the interface is good when fully charged.
  • the shell material has polar groups.
  • the core material includes a copolymer of styrene monomer units-butadiene monomer units.
  • the shell material includes a copolymer of styrene monomer units-butadiene monomer units-unsaturated acid monomer units-unsaturated ester monomer units.
  • the monomer corresponding to the unsaturated acid monomer unit includes one or more of acrylic acid, methacrylic acid, maleic acid, fumaric acid and itaconic acid.
  • the monomers corresponding to the unsaturated ester monomer units include methyl methacrylate, ethylhexyl, vinyl acetate, isooctyl acrylate, hydroxyethyl acrylate, isobornyl methacrylate, tert.
  • the viscosity of the aqueous solution of the binder when the solid content is 45% is 10 mPa ⁇ s to 200 mPa ⁇ s.
  • the volume average particle size Dv50 of the binder is 100 nm to 1000 nm.
  • the second aspect of the application provides a method for preparing an adhesive, including the following steps:
  • the mass ratio of the styrene monomer and the butadiene monomer is 10: (4-8).
  • the styrene monomer, the butadiene monomer, the unsaturated acid monomer and the unsaturated ester monomer are The mass ratio is 10:(4 ⁇ 8):(1 ⁇ 3):(2 ⁇ 4).
  • the third aspect of the present application provides a binder composition, including the binder of the first aspect of the present application or the binder prepared by the method of the second aspect of the present application and high viscosity carboxymethyl cellulose sodium, in
  • the viscosity of the high-viscosity sodium carboxymethyl cellulose aqueous solution at 25° C. is 10,000 mPa ⁇ s to 20,000 mPa ⁇ s when the solid content is 1%.
  • the mass ratio of the binder to the high-viscosity sodium carboxymethylcellulose is (1.1-3.5):1.
  • the hydrogen atom on the hydroxyl group in the high viscosity sodium carboxymethyl cellulose is replaced by a substituting agent, and the substituting agent reacts with the hydroxyl group to generate a hemiacetal;
  • the substituent includes a dialdehyde monomer; further optionally, the dialdehyde monomer includes one or both of glyoxal and glutaraldehyde.
  • a fourth aspect of the present application provides a negative electrode slurry, including the binder of the first aspect of the present application, the binder prepared by the method of the second aspect of the present application, or the binder composition of the third aspect of the present application.
  • the fifth aspect of the present application provides a preparation method of negative electrode slurry, the negative electrode slurry includes the binder composition, and the preparation method includes the following steps:
  • the step of preparing the high viscosity sodium carboxymethylcellulose is also included, which includes:
  • the substituent includes a dialdehyde monomer; further optionally, the dialdehyde monomer includes one or both of glyoxal and glutaraldehyde.
  • step S203 satisfies at least one of the following conditions I to III:
  • the temperature of the substitution reaction is 30°C to 70°C;
  • the substitution reaction time is 20 min to 120 min.
  • the sixth aspect of this application provides a negative electrode sheet, including:
  • a negative active material layer is located on at least one surface of the negative current collector
  • the negative active material layer includes the binder of the first aspect of the present application, the binder prepared by the method of the second aspect of the present application, or the binder composition of the third aspect of the present application.
  • the mass proportion of the binder in the negative active material layer is 1.3% to 2.1%, optionally 1.5% to 2.1%, further optionally 1.8% to 2.1% .
  • the negative active material layer includes the binder composition of the third aspect of the present application, and the mass proportion of the high viscosity sodium carboxymethylcellulose in the negative active material layer is 0.6% ⁇ 1.2%, optionally 0.8% ⁇ 1.2%, further optionally 0.9% ⁇ 1.2%.
  • a seventh aspect of the present application provides a secondary battery, including the negative electrode plate of the sixth aspect of the present application.
  • An eighth aspect of the present application provides a battery module, including the secondary battery of the seventh aspect of the present application.
  • a ninth aspect of the present application provides a battery pack, including the battery module of the eighth aspect of the present application.
  • a tenth aspect of the present application provides an electrical device, including at least one of the secondary battery of the seventh aspect of the present application, the battery module of the eighth aspect of the present application, or the battery pack of the ninth aspect of the present application.
  • Figure 1 is a viscosity-time curve of the negative electrode slurry in Example 23 of the present application.
  • Figure 2 is a graph of the bonding force versus time of the negative electrode piece in Example 23 of the present application.
  • Figure 3 is a discharge DCR histogram of the cells in Example 24, Example 25, Example 26 and Comparative Example 7 of the present application.
  • FIG. 4 is a schematic diagram of an embodiment of a secondary battery.
  • FIG. 5 is an exploded view of FIG. 4 .
  • Figure 6 is a schematic diagram of an embodiment of a battery module.
  • Figure 7 is a schematic diagram of an embodiment of a battery pack.
  • FIG. 8 is an exploded view of FIG. 7 .
  • FIG. 9 is a schematic diagram of an embodiment of a device in which a secondary battery is used as a power source.
  • Ranges disclosed herein are defined in terms of lower and upper limits. A given range is defined by selecting a lower limit and an upper limit that define the boundaries of the particular range. Ranges defined in this manner may be inclusive or exclusive of the endpoints, and may be arbitrarily combined, that is, any lower limit may be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, understand that ranges of 60-110 and 80-120 are also expected. Furthermore, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2- 3, 2-4 and 2-5.
  • the numerical range “a-b” represents an abbreviated representation of any combination of real numbers between a and b, where a and b are both real numbers.
  • the numerical range “0-5" means that all real numbers between "0-5" have been listed in this article, and "0-5" is just an abbreviation of these numerical combinations.
  • a certain parameter is an integer ⁇ 2
  • the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially.
  • step (c) means that step (c) may be added to the method in any order.
  • the method may include steps (a), (b) and (c). , may also include steps (a), (c) and (b), may also include steps (c), (a) and (b), etc.
  • the binders styrene-butadiene rubber and sodium carboxymethylcellulose are often used to prepare negative electrode sheets, which cannot take into account the processing performance of the negative electrode sheet and the dynamic performance of the battery core.
  • the technicians of this application found that this is mainly due to the use of styrene-butadiene rubber as a binder in a conventional dosage of 2% to 2.5% and hydroxymethylcellulose in a conventional dosage of 1% to 2% in the negative active material layer.
  • the negative electrode sheet made of sodium and the battery core corresponding to the negative electrode sheet have poor dynamic performance under high-power systems; if in order to improve the dynamic performance of the battery core, the addition of styrene-butadiene rubber and sodium hydroxymethylcellulose should be reduced.
  • the binder provided by this application includes: a core material with a glass transition temperature of -50°C to 0°C; a shell material located on at least part of the surface of the core material, and the shell material
  • the glass transition temperature is 60°C ⁇ 100°C.
  • the shell material is located on at least part of the surface of the core material, the core material is a soft material with a lower glass transition temperature, and the shell material is a hard material with a higher glass transition temperature.
  • the binder has a core-shell structure with a soft inside and a hard outside; the soft core material facilitates cold pressing of the negative electrode piece, helps reduce the cold pressing pressure, increases the maximum compaction density window of the negative active material, and provides Better adhesion can reduce the amount of binder.
  • the smaller amount of binder reduces the coating of the surface of the negative active material; the relatively hard shell material will not overshoot after the negative electrode sheet is cold-pressed.
  • the deformation reduces the coating area of the negative active material by the binder, effectively reduces the impedance during the insertion and extraction of lithium ions, and improves the dynamic performance of the battery core corresponding to the negative electrode piece.
  • the adhesive when the above-mentioned adhesive is applied to the battery core, the DC internal resistance (DCR) of the battery core is reduced by 5% to 12%, and the charging window is slightly increased.
  • the adhesive in this application has The bonding force is increased by more than 20%, there is no peeling or powder loss, and the interface is good when fully charged.
  • the shell material can cover the entire surface of the core material, or can only cover part of the surface of the core material. Preferably, the shell material covers the entire surface of the core material.
  • the polar group may include one or more of carboxyl, hydroxyl, carbonyl and ester groups.
  • the glass transition temperature of the core material and shell material mentioned above can be measured using a differential scanning calorimeter (DSC).
  • DSC differential scanning calorimeter
  • the specific method is as follows: 1. Sample preparation: weigh 1 to 3 mg of sample in an Al crucible, cover it Put the crucible lid on; 2. Parameter settings: nitrogen atmosphere, purge gas 50Ml/min, protective gas 100Ml/min; 3. Temperature rise program: 10°C/min, 35°C ⁇ -30°C, -30°C insulation for 3min; 10 °C/min, -30°C ⁇ 50°C; 4. Read the temperature at the maximum slope in the DSC curve which is the glass transition temperature.
  • the glass transition temperature of the core material is -50°C to 0°C; for example, it can be -50°C to -5°C, -50°C to -10°C, -50°C to -20°C, - 50°C ⁇ -30°C, -50°C ⁇ -40°C, -30°C ⁇ -0°C or -30°C ⁇ -10°C, etc.
  • the glass transition temperature of the shell material is 60°C to 100°C; for example, it can be 60°C to 95°C, 65°C to 90°C, 70°C to 85°C, or 70°C to 80°C.
  • the inventor found that when the binder of the present application satisfies one or more of the following conditions in addition to the above design conditions, the dynamic performance of the battery core can be further improved.
  • the shell material has polar groups.
  • the polar group can adjust the swelling ability of the binder in the electrolyte, so that the binder has higher swelling characteristics in the electrolyte, improves the transmission channel of lithium ions, and further improves the dynamic performance of the battery core; shell layer
  • the polar groups of the material can provide hydrogen bonding, further enhance the binding force of the binder to the negative active material, and improve the processing performance of the negative electrode piece.
  • the core material may include a copolymer of styrene monomer units-butadiene monomer units.
  • the shell material may include a copolymer of styrene monomer units-butadiene monomer units-unsaturated acid monomer units-unsaturated ester monomer units.
  • the copolymer of styrene monomer unit-butadiene monomer unit-unsaturated acid monomer unit-unsaturated ester monomer unit represents a copolymer of styrene monomer unit, butadiene monomer unit, unsaturated A copolymer composed of acid monomer units and unsaturated ester monomer units.
  • the copolymer includes styrene monomer units, butadiene monomer units, unsaturated acid monomer units and unsaturated ester monomer units. It does not Limit the order of styrene monomer units, butadiene monomer units, unsaturated acid monomer units and unsaturated ester monomer units in the copolymer.
  • the styrene monomer units, butadiene monomer units, The unsaturated acid monomer units and unsaturated ester monomer units may be arranged in any order.
  • the defined unsaturated acid is substituted, it should be understood that it is optionally substituted by groups acceptable in the art, including but not limited to: silyl, carbonyl, alkoxycarbonyl, aryloxycarbonyl, carbamoyl, Haloformyl, formyl, cyano, isocyanate, isocyanate, thiocyanate, isothiocyanate, hydroxyl, trifluoromethyl, nitro or halogen, and the above groups can also be further Substitution is acceptable in the art.
  • the monomer corresponding to the unsaturated acid monomer unit includes one or more of acrylic acid, methacrylic acid, maleic acid, fumaric acid and itaconic acid.
  • the defined unsaturated acid is substituted, it should be understood that it is optionally substituted by groups acceptable in the art, including but not limited to: silyl, carbonyl, alkoxycarbonyl, aryloxycarbonyl, carbamoyl, Haloformyl, formyl, cyano, isocyanate, isocyanate, thiocyanate, isothiocyanate, hydroxyl, trifluoromethyl, nitro or halogen, and the above groups can also be further Substitution is acceptable in the art.
  • groups acceptable in the art including but not limited to: silyl, carbonyl, alkoxycarbonyl, aryloxycarbonyl, carbamoyl, Haloformyl, formyl, cyano, isocyanate, isocyanate, thiocyanate, isothiocyanate, hydroxyl, trifluoromethyl, nitro or halogen, and the above groups can also be further Substitution is acceptable in the art.
  • the monomers corresponding to the unsaturated ester monomer units include methyl methacrylate, ethylhexyl, vinyl acetate, isooctyl acrylate, hydroxyethyl acrylate, isobornyl methacrylate, and tertiary carbonic acid.
  • vinyl ester butyl acrylate, acrylonitrile, ethyl acrylate, n-butyl acrylate and isobutyl acrylate.
  • the viscosity of the aqueous solution of the binder when the solid content is 45% is 10 mPa ⁇ s to 200 mPa ⁇ s; for example, it can be 10 mPa ⁇ s to 150 mPa ⁇ s, 20 mPa ⁇ s ⁇ 150mPa ⁇ s, 50mPa ⁇ s ⁇ 100mPa ⁇ s or 80mPa ⁇ s ⁇ 100mPa ⁇ s, etc.
  • the above-mentioned viscosity of the binder aqueous solution with a solid content of 45% at 25°C can be measured using the following method: weigh 500g of the binder aqueous solution to be tested with a solid content of 45%, and stir for 2 hours. Make sure the adhesive to be measured is completely stable and uniform before measurement. Detection temperature: 25 ⁇ 1°C; Used rotor and speed: 63# rotor, 12r/min, take the 6th minute value; Equipment model: DV-2TLV Brookfield viscometer.
  • the volume average particle diameter Dv50 of the binder is 100nm ⁇ 1000nm; for example, it can be 100nm ⁇ 900nm, 200nm ⁇ 900nm, 300nm ⁇ 600nm, 400nm ⁇ 600nm, or 500nm ⁇ 600nm, etc.
  • the volume average particle size Dv50 mentioned above refers to the particle size corresponding to 50% of the cumulative volume distribution.
  • Dv50 can be easily measured using a laser particle size analyzer, such as the Mastersizer 2000E laser particle size analyzer of Malvern Instruments Co., Ltd. in the United Kingdom, referring to the GB/T 19077-2016 particle size distribution laser diffraction method.
  • the embodiment of the present application also provides a method for preparing the above-mentioned adhesive, which includes the following steps:
  • the mass ratio of styrene monomer and butadiene monomer is 10:(4-8); for example, it can be 10:(4-7), 10 :(5 ⁇ 8) or 10:(5 ⁇ 6) etc.
  • the mass ratio of styrene monomer, butadiene monomer, unsaturated acid monomer and unsaturated ester monomer is 10: (4-8): (1 ⁇ 3):(2 ⁇ 4); for example, it can be 10:(4 ⁇ 7):(2 ⁇ 3):(2 ⁇ 3) or 10:(5 ⁇ 8):(1 ⁇ 2): (2 ⁇ 3) etc.
  • both the polymerization reaction for preparing the core material and the polymerization reaction for preparing the shell material require the participation of an emulsifier and an initiator.
  • the emulsifier may include sodium alkyl sulfate, sodium alkyl sulfonate, sodium alkyl diphenyl ether disulfonate, ammonium alkyl phenol ether sulfate, sodium alkyl phenol ether sulfosuccinate, p-phenylene ether Sodium ethylene sulfonate, sodium 2-acrylamide-2,2dimethylethane sulfonate, sodium alkyl allyl succinate sulfonate, sodium acrylamide isopropyl sulfonate, and 2-ethyl alkyl acrylate One or more sulfonate sodium salts.
  • the initiator may include one or more of sodium persulfate, ammonium persulfate, and potassium persulfate.
  • the embodiment of the present application also provides a binder composition, including the above-mentioned binder or the binder prepared by the above-mentioned method and high-viscosity carboxymethyl cellulose sodium.
  • a binder composition including the above-mentioned binder or the binder prepared by the above-mentioned method and high-viscosity carboxymethyl cellulose sodium.
  • the high-viscosity carboxymethyl cellulose The viscosity of the aqueous solution of cellulose sodium when the solid content is 1% is 10000mPa ⁇ s ⁇ 20000mPa ⁇ s; for example, it can be 10000mPa ⁇ s ⁇ 19000mPa ⁇ s, 10000mPa ⁇ s ⁇ 15000mPa ⁇ s, 13000mPa ⁇ s ⁇ 17000mPa ⁇ s Or 15000mPa ⁇ s ⁇ 20000mPa ⁇ s, etc.
  • the sodium carboxymethylcellulose used in the negative electrode plate has a viscosity of an aqueous solution with a solid content of 1% at 25°C of 2000mPa ⁇ s to 8000mPa ⁇ s, while the above-mentioned aqueous solution with a solid content of 1%
  • the viscosity of the aqueous solution of high-viscosity sodium carboxymethylcellulose increases significantly at 25°C.
  • Using high-viscosity sodium carboxymethylcellulose can appropriately reduce the dosage and reduce the activity on the negative electrode while ensuring the processing performance of the negative electrode piece.
  • the coating of the material surface reduces the migration resistance of lithium ions and improves the dynamic performance of the battery cell corresponding to the negative electrode piece.
  • the above-mentioned viscosity of the aqueous solution of high viscosity carboxymethylcellulose sodium at 25°C with a solid content of 1% can be measured using the following method: weigh 5.0g of dry weight of the high viscosity carboxymethyl cellulose to be measured. Cellulose sodium, add pure water until the total weight of the high viscosity sodium carboxymethyl cellulose to be measured and pure water is 500g, stir and dissolve for 2 hours to completely disperse the high viscosity sodium carboxymethyl cellulose to be measured, and measure according to Different rotors correspond to different viscosities. Detection temperature: 25 ⁇ 1°C; Used rotor and speed: 63# rotor, 12r/min, take the 6th minute value; Equipment model: DV-2TLV Brookfield viscometer.
  • the mass ratio of the binder to high-viscosity carboxymethylcellulose sodium is (1.1-3.5):1; for example, it can be (1.1-3):1, (1.6-2.6):1 , (1.8 ⁇ 2.2):1 or (2 ⁇ 2.2), etc. According to research by technicians, it is found that when the mass ratio of the binder and high-viscosity sodium carboxymethyl cellulose is within this range, it is beneficial to further improve the bonding force of the binder composition.
  • the hydrogen atom on the hydroxyl group in the high viscosity sodium carboxymethyl cellulose is replaced by a substituent, and the substituent reacts with the hydroxyl group to form a hemiacetal.
  • the high viscosity sodium carboxymethyl cellulose temporarily loses its hydrophilicity, preventing the high viscosity sodium carboxymethyl cellulose from immediately occurring when it comes into contact with water.
  • the agglomeration phenomenon is conducive to the rapid dispersion of high-viscosity carboxymethyl cellulose sodium in water.
  • hemiacetal can be hydrolyzed during the process of dissolving in water, regenerating hydroxyl groups and restoring hydrophilicity.
  • the substituent may include a dialdehyde monomer; further optionally, the dialdehyde monomer may include one or both of glyoxal and glutaraldehyde.
  • the embodiments of the present application also provide a preparation method of high viscosity sodium carboxymethyl cellulose, which includes the following steps:
  • the mass ratio of water and cotton fiber is (0.3 ⁇ 0.8):1, for example, it can be (0.3 ⁇ 0.7):1, (0.4 ⁇ 0.6):1 or (0.5 ⁇ 0.7):1, etc. .
  • the mass ratio of ethanol and cotton fiber is (1.0 ⁇ 2.0):1, for example, it can be (1.0 ⁇ 1.8):1, (1.1 ⁇ 1.7):1, (1.3 ⁇ 1.6):1 or (1.4 ⁇ 1.5):1 wait.
  • the alkalizing agent can be a sodium hydroxide aqueous solution with a mass percentage concentration of 30%-55%; the mass ratio of the alkalizing agent and cotton fiber is (0.6 ⁇ 1.0):1, for example, it can be (0.6 ⁇ 0.9):1, ( 0.7 ⁇ 1.0):1 or (0.7 ⁇ 0.8):1 etc.
  • the time of the alkalization reaction can be 30 to 80 minutes, and the temperature of the alkalization reaction can be 10°C to 40°C.
  • the etherifying agent may be an ethanol solution of chloroacetic acid with a mass percentage concentration of 50% to 80%.
  • the mass ratio of etherifying agent and cotton fiber is (1.0-1.5):1, for example, it can be (1.0-1.4):1 or (1.2-1.3):1, etc.
  • the time of the etherification reaction can be 40min to 70min, and the temperature of the etherification reaction can be 60°C to 90°C.
  • the substituent includes a dialdehyde monomer; further optionally, the dialdehyde monomer includes one or both of glyoxal and glutaraldehyde.
  • the mass ratio of the product of the etherification reaction to the substituent is 100:(0.2 ⁇ 1.0); for example, it can be 100:(0.2 ⁇ 0.8), 100:(0.3 ⁇ 0.7) or 100:( 0.4 ⁇ 0.6) etc.
  • the temperature of the substitution reaction is 30°C to 70°C; for example, it can be 30°C to 60°C, 40°C to 70°C, or 50°C to 60°C, etc.
  • the substitution reaction time is 20 min to 120 min; for example, it can be 20 min to 110 min, 30 min to 90 min, 40 min to 70 min, or 50 min to 60 min, etc.
  • the embodiments of the present application also provide a negative electrode slurry, including the above-mentioned binder, the above-mentioned binder prepared by the above-mentioned method, or the above-mentioned binder composition.
  • the embodiments of the present application also provide a preparation method of negative electrode slurry.
  • the negative electrode slurry contains a binder composition.
  • the preparation method includes the following steps:
  • high-viscosity sodium carboxymethylcellulose is added in two steps. First, a portion of high-viscosity sodium carboxymethylcellulose is added to infiltrate the negative electrode active material to promote the dispersion of the negative electrode active material in the aqueous slurry. Evenly, then stir and knead to obtain the negative active material agglomerate, and finally add the remaining high-viscosity sodium carboxymethylcellulose to stir the negative active material.
  • the high-viscosity sodium carboxymethylcellulose can suspend and disperse the negative active material.
  • the high viscosity sodium carboxymethyl cellulose can be quickly dispersed in water, compared with the sodium carboxymethyl cellulose used in traditional negative electrode slurry, it can reduce the stirring time, meet the 2-hour negative electrode stirring pulping process, and increase the stirring productivity .
  • the high viscosity sodium carboxymethyl cellulose is added in two times, and the mass ratio of the high viscosity sodium carboxymethyl cellulose added for the first time to the high viscosity sodium carboxymethyl cellulose added for the second time is It is (0.25 ⁇ 1):1; for example, it can be (0.25 ⁇ 0.9):1, (0.3 ⁇ 0.8):1 or (0.5 ⁇ 0.7):1, etc.
  • the embodiment of the present application also provides a negative electrode sheet, including:
  • a negative active material layer located on at least one surface of the negative current collector
  • the negative active material layer includes the above-mentioned binder, the above-mentioned negative electrode binder prepared by the above-mentioned method or the above-mentioned binder composition.
  • the mass proportion of the binder in the negative active material layer is 1.3% to 2.1%, optionally 1.5% to 2.1%, further optionally 1.8% to 2.1%.
  • the amount of binder used in the negative active material layer is significantly lower than the amount of styrene-butadiene rubber used as the binder in traditional technology.
  • the mass proportion of the above-mentioned binder in the negative active material layer can be measured using the following method: first measure the mass M1 of the binder in the negative active material layer, and then measure the mass M0 of the negative active material layer, based on the formula M1/M0*100% is calculated to obtain the mass proportion of the binder in the negative active material layer.
  • the negative active material layer includes the above-mentioned binder composition, and the mass proportion of high-viscosity sodium carboxymethyl cellulose in the negative active material layer is 0.6% to 1.2%, optionally 0.8% ⁇ 1.2%, further optionally 0.9% ⁇ 1.2%.
  • the mass proportion of carboxymethylcellulose sodium in the negative active material layer is usually 1% to 2%, but in the embodiment of the present application, the high viscosity sodium carboxymethylcellulose is in the negative active material layer. The quality ratio has dropped significantly.
  • the mass proportion of the above-mentioned high-viscosity carboxymethylcellulose sodium in the negative electrode active material layer can be measured as follows: first measure the mass M2 of the high-viscosity sodium carboxymethylcellulose in the negative electrode active material layer, and then measure the negative electrode activity. The mass M0 of the material layer is calculated based on the formula M2/M0*100% to obtain the mass proportion of high-viscosity sodium carboxymethyl cellulose in the negative active material layer.
  • the negative electrode current collector can use conventional metal foil or composite current collector.
  • the metal foil may be copper foil.
  • the composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base material.
  • the composite current collector can be formed by forming metal materials (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyterephthalate It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the negative active material layer usually also includes negative active material, conductive agent and other optional auxiliaries.
  • the negative active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, and the like.
  • the silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon carbon composites, silicon nitrogen composites and silicon alloys.
  • the tin-based material may be selected from at least one of elemental tin, tin oxide compounds and tin alloys.
  • the present application is not limited to these materials, and other traditional materials that can be used as battery negative electrode active materials can also be used. Only one type of these negative electrode active materials may be used alone, or two or more types may be used in combination.
  • the conductive agent may be one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • PTC thermistor materials may be PTC thermistor materials, etc.
  • the negative electrode sheet can be prepared by dispersing the above-mentioned components for preparing the negative electrode sheet, such as negative active material, conductive agent, binder and any other components in a solvent (such as deionized water) , to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode piece can be obtained.
  • a solvent such as deionized water
  • Secondary batteries refer to batteries that can be recharged to activate active materials and continue to be used after the battery is discharged.
  • a secondary battery includes a positive electrode sheet, the negative electrode sheet provided above in this application, a separator and an electrolyte.
  • active ions are inserted and detached back and forth between the positive and negative electrodes.
  • the isolation film is arranged between the positive electrode piece and the negative electrode piece to play the role of isolation.
  • the electrolyte plays a role in conducting ions between the positive and negative electrodes.
  • a positive electrode sheet usually includes a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector.
  • the positive electrode film layer includes a positive electrode active material.
  • the positive electrode current collector has two surfaces facing each other in its own 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 current collector may use a metal foil or a composite current collector.
  • the metal foil aluminum foil can be used.
  • the composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer.
  • the composite current collector can be formed by forming metal materials (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on polymer material substrates (such as polypropylene (PP), polyterephthalate It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the cathode active material may be a cathode active material known in the art for lithium ion batteries.
  • the cathode active material may include at least one of the following materials: an olivine-structured lithium-containing phosphate, a lithium transition metal oxide, and their respective modified compounds.
  • the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials of batteries can also be used. Only one type of these positive electrode active materials may be used alone, or two or more types may be used in combination.
  • lithium transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO 2 ), lithium nickel oxides (such as LiNiO 2 ), lithium manganese oxides (such as LiMnO 2 , LiMn 2 O 4 ), lithium Nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1/3 Co 1/3 Mn 1/3 O 2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (can also be abbreviated to NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O 2 (can also be abbreviated to NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (can also be abbreviated to NCM 622 ), LiNi At least one of 0.8 Co 0.1 Mn 0.1 O 2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as Li Li
  • the olivine structure contains Examples of lithium phosphates may include, but are not limited to, lithium iron phosphate (such as LiFePO 4 (also referred to as LFP)), composites of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), lithium manganese phosphate and carbon. At least one of composite materials, lithium iron manganese phosphate, and composite materials of lithium iron manganese phosphate and carbon.
  • lithium iron phosphate such as LiFePO 4 (also referred to as LFP)
  • composites of lithium iron phosphate and carbon such as LiMnPO 4
  • LiMnPO 4 lithium manganese phosphate and carbon.
  • At least one of composite materials, lithium iron manganese phosphate, and composite materials of lithium iron manganese phosphate and carbon At least one of composite materials, lithium iron manganese phosphate, and composite materials of lithium iron manganese phosphate and carbon.
  • the cathode active material may be a cathode active material known in the art for sodium-ion batteries.
  • the cathode active material may be a cathode active material known in the art for sodium-ion batteries.
  • only one type of positive electrode active material may be used alone, or two or more types may be combined.
  • the positive active material can be selected from sodium iron composite oxide (NaFeO 2 ), sodium cobalt composite oxide (NaCoO 2 ), sodium chromium composite oxide (NaCrO 2 ), sodium manganese composite oxide (NaMnO 2 ), sodium nickel Composite oxide (NaNiO 2 ), sodium nickel titanium composite oxide (NaNi 1/2 Ti 1/2 O 2 ), sodium nickel manganese composite oxide (NaNi 1/2 Mn 1/2 O 2 ), sodium iron manganese composite Oxide (Na 2/3 Fe 1/3 Mn 2/3 O 2 ), sodium nickel cobalt manganese composite oxide (NaNi 1/3 Co 1/3 Mn 1/3 O 2 ), sodium iron phosphate compound (NaFePO 4 ), sodium manganese phosphate compound (NaMn P O 4 ), sodium cobalt phosphate compound (NaCoPO 4 ), Prussian blue materials, polyanionic materials (phosphates, fluorophosphates, pyrophosphates, sulfates), etc.,
  • the positive electrode film layer also optionally includes binders, conductive agents and other optional auxiliaries.
  • the binder may include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene At least one of ethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer and fluorine-containing acrylate resin.
  • PVDF polyvinylidene fluoride
  • PTFE polytetrafluoroethylene
  • PTFE polytetrafluoroethylene
  • VDF polytetrafluoroethylene
  • PTFE polytetrafluoroethylene
  • VDF polytetrafluoroethylene
  • PTFE polytetrafluoroethylene
  • VDF polytetrafluoroethylene
  • PTFE polytetrafluoroethylene
  • PTFE polytetrafluoroethylene
  • the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • the positive electrode sheet can be prepared in the following manner: the above-mentioned components for preparing the positive electrode sheet, such as the positive active material, the conductive agent, the binder and any other components are dispersed in a solvent (such as N-methyl pyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode piece can be obtained.
  • a solvent such as N-methyl pyrrolidone
  • the secondary battery further includes a separator film.
  • a separator film There is no particular restriction on the type of isolation membrane in this application. Any well-known porous structure isolation membrane with good chemical stability and mechanical stability can be used.
  • the material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.
  • the isolation film can be a single-layer film or a multi-layer composite film, with no special restrictions. When the isolation film is a multi-layer composite film, the materials of each layer can be the same or different, and there is no particular limitation.
  • the positive electrode piece, the negative electrode piece and the separator film can be made into an electrode assembly through a winding process or a lamination process.
  • the secondary battery may include an electrolyte that serves to conduct ions between a positive electrode and a negative electrode.
  • the electrolyte solution may include electrolyte salts and solvents.
  • the electrolyte salt may be selected from lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium perchlorate (LiClO 4 ), lithium hexafluoroarsenate (LiAsF 6 ), lithium bisfluorosulfonimide ( LiFSI), lithium bistrifluoromethanesulfonimide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluoromethanesulfonate borate (LiDFOB), lithium dioxalatoborate (LiBOB), lithium difluorophosphate (LiPO 2 F 2 ), one or more of lithium difluorodioxalate phosphate (LiDFOP) and lithium tetrafluorooxalate phosphate (LiTFOP).
  • LiFSI lithium bisfluorosulfonimide
  • LiTFSI lithium bistrifluorome
  • the solvent may be selected from ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), carbonic acid Dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), One or more of ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS) and diethyl sulf
  • additives are also included in the electrolyte.
  • additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain properties of the battery, such as additives that improve the overcharge performance of the battery, additives that improve the high-temperature performance of the battery, and additives that improve the low-temperature performance of the battery. Additives etc.
  • the secondary battery of the present application is a lithium-ion secondary battery.
  • the secondary battery can be prepared according to conventional methods in the art, for example, the positive electrode sheet, the separator film, and the negative electrode sheet are wound (or stacked) in order, so that the separator film is between the positive electrode sheet and the negative electrode sheet for isolation. function to obtain the battery core, place the battery core in the outer package, inject the electrolyte and seal it to obtain a secondary battery.
  • FIG. 4 shows an example of a square-structured secondary battery 5 .
  • the secondary battery may include an outer packaging.
  • the outer packaging can be used to package the above-mentioned electrode assembly and electrolyte.
  • the outer packaging of the secondary battery may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc.
  • 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 may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, polybutylene succinate, and the like.
  • the outer package may include a housing 51 and a cover 53 .
  • the housing 51 may include a bottom plate and side plates connected to the bottom plate, and the bottom plate and the side plates enclose to form a receiving cavity.
  • the housing 51 has an opening communicating with the accommodation cavity, and the cover plate 53 can cover the opening to close the accommodation cavity.
  • the positive electrode piece, the negative electrode piece and the isolation film can be formed into the electrode assembly 52 through a winding process or a lamination process.
  • the electrode assembly 52 is packaged in the containing cavity.
  • the electrolyte soaks into the electrode assembly 52 .
  • the number of electrode assemblies 52 contained in the secondary battery 5 can be one or more, and can be adjusted according to needs.
  • secondary batteries can be assembled into battery modules, and the number of secondary batteries contained in the battery module can be multiple. The specific number can be adjusted according to the application and capacity of the battery module.
  • FIG. 6 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 can be fixed by fasteners.
  • the battery module 4 may further include a housing having a receiving space in which a plurality of secondary batteries 5 are received.
  • 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 arranged in the battery box.
  • the battery box includes an upper box 2 and a lower box 3 .
  • the upper box 2 can be covered with the lower box 3 and form a closed space for accommodating the battery module 4 .
  • Multiple battery modules 4 can be arranged in the battery box in any manner.
  • the present application also provides an electrical device, which includes at least one of the secondary battery, battery module, or battery pack.
  • the secondary battery, battery module or battery pack may be used as a power source for the device or as an energy storage unit for the device.
  • the device may be, but is not limited to, a mobile device (such as a mobile phone, a laptop, etc.), an electric vehicle (such as a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, or an electric golf ball). vehicles, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.
  • the device can select secondary batteries, battery modules or battery packs according to its usage requirements.
  • FIG. 9 shows an electrical device 6 as an example.
  • the electric device 6 is a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or the like.
  • battery packs or battery modules can be used.
  • the device may be a mobile phone, a tablet, a laptop, etc.
  • the device is usually required to be thin and light, and a secondary battery can be used as a power source.
  • the adhesive includes a core material and a shell material covering the surface of the core material.
  • the glass transition temperature of the core material is -30°C
  • the glass transition temperature of the shell material is 80°C
  • the viscosity of an aqueous solution of a binder with a solid content of 1% at 25°C is 100mPa ⁇ s.
  • the volume average particle size Dv50 is 500nm.
  • Examples 2-14 are basically the same as Example 1, except for the following: the type and/or amount of monomers used when preparing the core material, the type and/or amount of monomers used when preparing the shell material, and the glass transition of the core material. At least one of the parameters including temperature, the glass transition temperature of the shell material, the viscosity of an aqueous solution of the binder with a solid content of 1% at 25°C, and the volume average particle size Dv50 of the binder is different, as follows: As shown in Table 1.
  • the pH value of the reaction kettle, the temperature of the reaction kettle and the reaction time in step 1) and/or the temperature of the reaction kettle in step 2) are further adjusted;
  • the pH value of the reaction kettle in step 1) of Example 2 is 4.5, the temperature of the reaction kettle is 60°C, and the reaction time is 50 min; the temperature of the reaction kettle in step 2) is 85°C.
  • the pH value of the reaction kettle in step 1) in Example 3 is 5.5, the temperature of the reaction kettle is 80°C, and the reaction time is 30 min; the temperature of the reaction kettle in step 2) is 83°C.
  • Comparative Example 1 only the core material was prepared, and the adhesive of Comparative Example 1 was obtained according to the same preparation method as step 1) in Example 1.
  • Comparative Example 2 the shell material was directly prepared, and the adhesive of Comparative Example 2 was obtained according to the same preparation method as step 2) in Example 1.
  • Comparative Examples 3-4 are basically the same as Example 1, and the only difference is that the amount of monomer used in preparing the shell material is different, as shown in Table 1 below.
  • Viscosity and volume average particle size Dv50, Dv50 represents the particle size corresponding to when the cumulative volume distribution percentage of the binder reaches 50%.
  • Glass transition temperature of the core material Use a differential scanning calorimeter (DSC) to test the glass transition temperature of the core material.
  • DSC differential scanning calorimeter
  • the specific process is as follows: 1. Sample preparation: weigh 1 to 3 mg of the core material in an Al crucible, and cover the crucible. Cover; 2. Parameter settings: nitrogen atmosphere, purge gas 50Ml/min, protective gas 100Ml/min; 3. Temperature rise program: 10°C/min, 35°C ⁇ -30°C, -30°C insulation for 3min; 10°C/ min, -30°C ⁇ 50°C; 4. Read the temperature at the maximum slope in the DSC curve as the glass transition temperature of the core material.
  • Glass transition temperature of shell material Use a differential scanning calorimeter (DSC) to test the glass transition temperature of the core material.
  • DSC differential scanning calorimeter
  • the specific process is as follows: 1. Sample preparation: weigh 1 to 3 mg of core material in an Al crucible and cover it. Crucible lid; 2. Parameter settings: nitrogen atmosphere, purge gas 50Ml/min, protective gas 100Ml/min; 3. Temperature rise program: 10°C/min, 35°C ⁇ -30°C, -30°C insulation for 3min; 10°C /min, -30°C ⁇ 50°C; 4. Read the temperature at the maximum slope in the DSC curve, which is the glass transition temperature of the shell material.
  • Viscosity of the emulsion containing the binder at 25°C Weigh 500g of the emulsion of the binder to be tested, stir and dissolve for 2 hours to make the binder to be tested completely stable and uniform, and then measure. Detection temperature: 25 ⁇ 1°C; Used rotor and speed: 63# rotor, 12r/min, take the 6th minute value; Equipment model: DV-2TLV Brookfield viscometer.
  • Volume average particle size Dv50 Measured with a laser particle size analyzer (such as Mastersizer 2000E laser particle size analyzer) with reference to the GB/T 19077-2016 particle size distribution laser diffraction method.
  • a laser particle size analyzer such as Mastersizer 2000E laser particle size analyzer
  • Tg1 in Table 1 represents the glass transition temperature of the core material
  • Tg2 represents the glass transition temperature of the shell material.
  • Viscosity refers to the viscosity of an aqueous solution of a binder with a solid content of 1% at 25°C.
  • Embodiments 16-20 are basically the same as Embodiment 15. The differences are: the amount of ethanol, the amount of water, the concentration of the sodium hydroxide aqueous solution, the amount of the sodium hydroxide aqueous solution, the time of the alkalization reaction, and the simplified reaction in step 1) The temperature; and/or the concentration of the ethanol solution of chloroacetic acid in step 2), the amount of the ethanol solution of chloroacetic acid, the time of the etherification reaction, the temperature of the etherification reaction; and/or the type of substituent in step 3) /Or at least one of the dosage, the time of the substitution reaction, and the temperature of the substitution reaction is different, as shown in Table 2 below.
  • Embodiment 21 The difference between Embodiment 21 and Embodiment 15 is that: only the alkalinization reaction and the etherification reaction were carried out, and the substitution reaction was not carried out.
  • the alkaline reaction was carried out according to the same alkalizing method as step 1) in Example 15, and the etherification reaction was carried out according to the embodiment.
  • the same etherification method as step 2) in 15. The details are shown in Table 2 below.
  • the viscosity of the aqueous solution of the high-viscosity sodium carboxymethylcellulose in Examples 15 to 21 at 25° C. and with a solid content of 1% was tested.
  • the test method is as follows:
  • the viscosity in Table 2 refers to the viscosity of the aqueous solution of high viscosity sodium carboxymethylcellulose at 25°C and with a solid content of 1%.
  • Examples 23-32 and 34-56 are basically the same as Example 21, the only difference lies in: the amount of negative active material, the type and/or amount of binder, and the type and/or amount of high viscosity sodium carboxymethylcellulose. At least one item is different, as shown in Table 3 below.
  • Example 33 The difference between Example 33 and Example 22 is that a 2h stirring process is used, and the preparation process is as follows:
  • Comparative Examples 7-11 are basically the same as Example 22, the only difference being that at least one of the amount of negative active material, type and/or amount of binder, and type and/or amount of high viscosity sodium carboxymethylcellulose is different. The details are shown in Table 3 below.
  • the negative electrode slurry prepared in Examples 22-56 and Comparative Examples 7-11 was subjected to a slurry stability test.
  • the specific test process is as follows:
  • the viscosity-time curve of the negative electrode slurry in Example 23 is as shown in Figure 1.
  • the abscissa in Figure 1 is the test time, and the ordinate is the viscosity value of the negative electrode slurry.
  • Figure 1 when the negative electrode slurry is left standing for 24 hours, the viscosity of the negative electrode slurry almost remains unchanged, indicating that the viscosity stability of the negative electrode slurry is good.
  • high viscosity CMC represents high viscosity sodium carboxymethyl cellulose
  • conventional CMC represents conventional sodium carboxymethyl cellulose.
  • the conventional process refers to the negative electrode slurry preparation process used in Example 22, and the 2-hour stirring process refers to the negative electrode slurry preparation process used in Example 33.
  • the viscosity of conventional CMC is 5000mPa ⁇ s.
  • the negative electrode slurries in Examples 22-56 and Comparative Examples 7-11 were evenly coated on the negative electrode current collector copper foil, and the weight of one side was controlled at 60-80 mg/1540.25mm 2 , and then dried, cold pressed, Cut it to obtain the negative electrode piece.
  • the negative electrode piece as the electrode piece to be tested, use a blade to cut out a pole piece sample with a width of 30mm and a length of 100-160mm, and paste the special double-sided tape on the steel plate with a width of 20mm and a length of 90-150mm, stick the intercepted pole piece sample on the double-sided tape, with the test side facing down, and then roll it three times in the same direction with a pressure roller, so that the width is the same as the pole piece sample, and the length is longer than the pole piece. Insert a paper tape with a sample length of 80 to 200 mm under the pole piece sample and fix it with wrinkle glue.
  • the indicator light will be on, adjust the limit block to the appropriate position, and use the end of the steel plate that is not attached to the pole piece sample.
  • Fix the clamp. Fold the paper tape upward and fix it with the upper clamp.
  • Software icon perform the test, the stretching rate is 50m/min, the test distance is 50mm, and the software takes a data point every 10s.
  • the bonding force of the negative electrode piece in Example 23 was measured three times in parallel.
  • the bonding force-time curve of the negative electrode piece in Example 23 is shown in Figure 2.
  • the ordinate is the bonding force and the abscissa is the test distance.
  • the average value of the bonding force of the negative electrode sheet in Example 23 measured three times is higher than 15 N/m, indicating that the bonding force of the negative electrode sheet is good.
  • Preparation of the positive electrode sheet Combine the positive active material LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811), the binder polyvinylidene fluoride (PVDF), and the conductive agent acetylene black in a mass ratio of 97%:1.5%:1.5 % is dissolved in the solvent N-methylpyrrolidone (NMP), stir thoroughly and mix evenly to prepare a positive electrode slurry; the positive electrode slurry is evenly coated on the positive electrode current collector aluminum foil, and then dried, cold pressed, and cut. Get the positive electrode piece.
  • NMP N-methylpyrrolidone
  • Isolation film Polyethylene film (PE) with a thickness of 12 ⁇ m is used as the isolation film.
  • the battery DC impedance test was performed on the cells prepared in Examples 22-56 and Comparative Examples 7-11.
  • the specific test process is as follows:
  • the battery corresponding to Example 1 was charged to 4.2V at a constant current of 1C, and then charged to a current of 0.05C at a constant voltage of 4.2V. After leaving it aside for 5 minutes, it was discharged at a constant current of 1C for 12 minutes, and the voltage V1 was recorded. After leaving it for 5 minutes, place it at -10°C for 2 hours, then discharge it at 15C for 10 seconds, record the voltage V2, then (V2-V1)/15C, get the DCR of the battery cell.
  • Example 22 Based on the DCR of the battery cells in Comparative Example 7, calculate the increase ratio of the internal resistance of the battery cells in Examples 22-56 and Comparative Examples 7-11.
  • the calculation method for the increase ratio of battery core internal resistance in other embodiments is the same as above.
  • the results of the cell internal resistance increase ratio of the cells in Examples 22-56 and Comparative Examples 7-11 are shown in Table 4 below.
  • Figure 3 is a discharge DCR histogram of the cells of Example 24, Example 25, Example 26 and Comparative Example 7. As can be seen from Figure 3, the DCR of the battery core is significantly reduced, indicating that the dynamic performance of the battery core is significantly improved.
  • the negative electrode weight in Table 4 refers to the weight of the negative electrode piece per unit area.
  • Example 1 and Comparative Examples 3-4 in Table 1 that by optimizing the amounts of unsaturated acid monomers and unsaturated ester monomers used in preparing the binder shell material, the glass transition of the shell material can be achieved. The temperature falls within the binder's required range.
  • Example 39 and Comparative Examples 7-11 in Tables 1-4 that by disposing the binder of the embodiment of the present invention in the negative active material layer of the negative electrode piece, the binder strength of the negative electrode piece can be improved. It meets the processing performance of the negative electrode piece; at the same time, it can also reduce the DC internal resistance of the battery core, thereby improving the dynamic performance of the battery core.
  • the negative electrode sheet can be further improved.
  • the adhesive force of the electrode piece meets the processing performance of the negative electrode piece; at the same time, it further reduces the DC internal resistance of the battery core and improves the dynamic performance of the battery core.
  • higher electrode piece bonding force and lower battery core DC internal resistance can be obtained. block.
  • the difference between Examples 22-25 and 35-36 is that the mass proportion of the binder in the negative active material layer is different; preferably, when the mass proportion of the binder is 1.3% to 2.1%, the negative electrode piece The processing performance is good, and the dynamic performance of the battery core is excellent; more preferably, the mass proportion of the binder is 1.5% to 2.1%; further preferably, the mass proportion of the binder is 7.8% to 2.1%.
  • the difference between Examples 26 to 33 and Examples 37 to 38 is that the mass proportion of high viscosity sodium carboxymethyl cellulose in the negative active material layer is different; preferably, when the mass proportion of high viscosity sodium carboxymethyl cellulose is 0.6 % ⁇ 1.0%, the negative electrode sheet has good processing performance, and the dynamic performance of the battery cell is excellent; more preferably, the mass proportion of high viscosity sodium carboxymethyl cellulose is 0.6% ⁇ 1.0%; further preferably, the mass proportion of high viscosity carboxymethylcellulose sodium The mass proportion of sodium methylcellulose is 0.9% to 1.0%.
  • Example 24 The difference between Example 24 and Example 33 is that the stirring process is different.
  • the negative electrode slurry is prepared using the binder and high-viscosity carboxymethyl cellulose sodium in the embodiment of the present invention, which can meet the 2-hour negative electrode stirring pulping process and improve the stirring productivity. .

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Abstract

本申请涉及一种粘结剂、粘结剂组合物、制备方法、负极浆料、负极极片、二次电池、电池模块、电池包及用电装置。其中的粘结剂，包括：内核材料，所述内核材料的玻璃化转变温度为-50℃～0℃；壳层材料，位于所述内核材料的至少部分表面上，所述壳层材料的玻璃化转变温度为60℃～100℃。

Description

粘结剂、粘结剂组合物、制备方法、负极浆料、负极极片、二次电池、电池模块、电池包及用电装置 技术领域
本申请属于二次电池技术领域，具体涉及一种粘结剂、粘结剂组合物、制备方法、负极浆料、负极极片、二次电池、电池模块、电池包及用电装置。
背景技术
二次电池因具有重量轻、无污染、无记忆效应等突出特点，被广泛应用于各类消费类电子产品和电动车辆中。随着新能源行业的不断发展，客户对二次电池提出了更高的使用需求。
相关技术中，多采用粘结剂丁苯橡胶和羧甲基纤维素钠制备负极极片，不能够兼顾负极极片的加工性能和负极极片对应的电芯的动力学性能。因此，传统的用于负极极片的粘结剂有待改进。
发明内容
鉴于背景技术中存在的技术问题，本申请提供一种粘结剂、粘结剂组合物、制备方法、负极浆料、负极极片、二次电池、电池模块、电池包及用电装置，旨在同时满足负极极片的加工性能和负极极片对应的电芯的动力学性能。
为了实现上述目的，本申请的第一方面提供一种粘结剂，包括：
内核材料，所述内核材料的玻璃化转变温度为-50℃～0℃；
壳层材料，位于所述内核材料的至少部分表面上，所述壳层材料的玻璃化转变温度为60℃～100℃。
相对于现有技术，本申请至少包括如下所述的有益效果：
本申请的粘结剂，壳层材料位于内核材料的至少部分表面上，内核材料为玻璃化转变温度较低的柔软材料，壳层材料为玻璃化转变温度较高的坚硬材料，则粘结剂为内软外硬的核壳结构；柔软的内核材料利于负极极片冷压，有助于减少冷压压力，提升负极活性物质的压密窗口，并提供较好的粘结力，进而能够减少粘结剂用量，较少的粘结剂用量减少了对负极活性物质表面的包覆；相对较硬的壳层材料在负极极片冷压后不会发生过度形变，降低了粘结剂对负极活性物质的包覆面积，有效减少锂离子嵌入和脱出时的阻抗，提升负极极片对应的电芯的动力学性能。如此上述粘结剂应用于电芯，电芯的 直流内阻(DCR)降低5％～12％，充电窗口轻微提升；相比于传统技术中采用的丁苯橡胶，本申请中粘结剂的粘结力提升20％以上，无脱膜、掉粉，满充界面良好。
在本申请任意实施方式中，所述壳层材料具有极性基团。
在本申请任意实施方式中，所述内核材料包括苯乙烯单体单元-丁二烯单体单元的共聚物。
在本申请任意实施方式中，所述壳层材料包括苯乙烯单体单元-丁二烯单体单元-不饱和酸单体单元-不饱和酯单体单元的共聚物。
在本申请任意实施方式中，所述不饱和酸单体单元对应的单体包括取代或未取代的含-C＝C-且碳原子数为3～6的不饱和酸；
可选地，所述不饱和酸单体单元对应的单体包括丙烯酸、甲基丙烯酸、马来酸、富马酸及衣康酸中的一种或多种。
在本申请任意实施方式中，所述不饱和酯单体单元对应的单体包括取代或未取代的含-C＝C-的不饱和酯；
可选地，所述不饱和酯单体单元对应的单体包括甲基丙烯酸甲酯、乙基已酯、乙酸乙烯酯、丙烯酸异辛酯、丙烯酸羟乙酯、甲基丙烯酸异冰片酯、叔碳酸乙烯酯、丙烯酸丁酯、丙烯氰、丙烯酸乙酯、丙烯酸正丁酯及丙烯酸异丁酯中的一种或多种。
在本申请任意实施方式中，在25℃时，所述粘结剂的水溶液的固含量为45％时的粘度为10mPa·s～200mPa·s。
在本申请任意实施方式中，所述粘结剂的体积平均粒径Dv50为100nm～1000nm。
本申请的第二方面提供一种粘结剂的制备方法，包括如下步骤
S11、苯乙烯单体与丁二烯单体发生聚合反应，制备所述内核材料；
S12、苯乙烯单体、丁二烯单体、不饱和酸类单体与不饱和酯类单体在所述内核材料的表面发生聚合反应。
在本申请任意实施方式中，制备所述内核材料的聚合反应中，所述苯乙烯单体和所述丁二烯单体的质量比为10:(4～8)。
在本申请任意实施方式中，制备所述壳层材料的聚合反应中，所述苯乙烯单体、所述丁二烯单体、所述不饱和酸单体和所述不饱和酯单体的质量比为10:(4～8):(1～3):(2～4)。
本申请的第三方面提供一种粘结剂组合物，包括本申请第一方面的粘结剂或者包括本申请第二方面的方法制备的粘结剂及高粘度羧甲基纤维素钠，在25℃时所述高粘度 羧甲基纤维素钠的水溶液的固含量为1％时的粘度为10000mPa·s～20000mPa·s。
在本申请任意实施方式中，所述粘结剂与所述高粘度羧甲基纤维素钠的质量比为(1.1～3.5):1。
在本申请任意实施方式中，所述高粘度羧甲基纤维素钠中羟基上的氢原子被取代剂取代，所述取代剂与所述羟基反应生成半缩醛；
可选地，所述取代剂包括二醛类单体；进一步可选地，所述二醛类单体包括乙二醛及戊二醛中的一种或两种。
本申请的第四方面提供一种负极浆料，包括本申请第一方面的粘结剂、本申请第二方面的方法制备的粘结剂或本申请第三方面的粘结剂组合物。
本申请的第五方面提供一种负极浆料的制备方法，所述负极浆料包含所述粘结剂组合物，所述制备方法包括如下步骤：
S21、将负极活性物质、一部分所述高粘度羧甲基纤维素钠、导电剂及一部分溶剂，制得负极活性物质团聚物；
S22、向所述负极活性物质团聚物中加入剩余部分所述高粘度羧甲基纤维素钠、剩余部分溶剂及所述粘结剂，制得所述负极浆料。
在本申请任意实施方式中，还包括制备所述高粘度羧甲基纤维素钠的步骤，其包括：
S201、使棉纤维与碱化剂在乙醇和水的混合溶液中，发生碱化反应；
S202、在碱化反应结束后，向反应体系中加入醚化剂，发生醚化反应；
S203、使醚化反应的产物与取代剂发生取代反应，制得所述高粘度羧甲基纤维素钠；
可选地，所述取代剂包括二醛类单体；进一步可选地，所述二醛类单体包括乙二醛及戊二醛中的一种或两种。
在本申请任意实施方式中，步骤S203满足下述Ⅰ～Ⅲ中的至少一个条件：
Ⅰ、所述醚化反应的产物与所述取代剂的质量比为：100:(0.2～1.0)；
Ⅱ、所述取代反应的温度为30℃～70℃；
Ⅲ、所述取代反应的时间为20min～120min。
本申请的第六方面提供一种负极极片，包括：
负极集流体；及
负极活性物质层，位于所述负极集流体的至少一个表面上；
其中，所述负极活性物质层包括本申请第一方面的粘结剂、本申请第二方面的方法 制备的粘结剂或本申请第三方面的粘结剂组合物。
在本申请任意实施方式中，所述粘结剂在所述负极活性物质层中的质量占比为1.3％～2.1％，可选为1.5％～2.1％，进一步可选为1.8％～2.1％。
在本申请任意实施方式中，所述负极活性物质层包括本申请第三方面的粘结剂组合物，所述高粘度羧甲基纤维素钠在所述负极活性物质层中的质量占比为0.6％～1.2％，可选为0.8％～1.2％，进一步可选为0.9％～1.2％。
本申请的第七方面提供一种二次电池，包括本申请第六方面的负极极片。
本申请的第八方面提供一种电池模块，包括本申请第七方面的二次电池。
本申请的第九方面提供一种电池包，包括本申请八方面的电池模块。
本申请的第十方面提供一种用电装置，包括本申请第七方面的二次电池、本申请第八方面的电池模块或本申请第九方面的电池包中的至少一种。
附图说明
为了更清楚地说明本申请的技术方案，下面将对本申请中所使用的附图作简单介绍。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是本申请实施例23中负极浆料的粘度-时间曲线图。
图2是本申请实施例23中负极极片的粘结力-时间曲线图。
图3是本申请实施例24、实施例25、实施例26及对比例7中电芯的放电DCR柱状图。
图4是二次电池的一实施方式的示意图。
图5是图4的分解图。
图6是电池模块的一实施方式的示意图。
图7是电池包的一实施方式的示意图。
图8是图7的分解图。
图9是二次电池用作电源的装置的一实施方式的示意图。
附图标记说明：
1、电池包；2、上箱体；3、下箱体；4、电池模块；5、二次电池；51、壳体；52、电极组件；53、盖板；6、用电装置。
具体实施方式
下面结合具体实施方式，进一步阐述本申请。应理解，这些具体实施方式仅用于说明本申请而不用于限制本申请的范围。
本申请所公开的“范围”以下限和上限的形式来限定，给定范围是通过选定一个下限和一个上限进行限定的，选定的下限和上限限定了特别范围的边界。这种方式进行限定的范围可以是包括端值或不包括端值的，并且可以进行任意地组合，即任何下限可以与任何上限组合形成一个范围。例如，如果针对特定参数列出了60-120和80-110的范围，理解为60-110和80-120的范围也是预料到的。此外，如果列出的最小范围值1和2，和如果列出了最大范围值3，4和5，则下面的范围可全部预料到：1-3、1-4、1-5、2-3、2-4和2-5。在本申请中，除非有其他说明，数值范围“a-b”表示a到b之间的任意实数组合的缩略表示，其中a和b都是实数。例如数值范围“0-5”表示本文中已经全部列出了“0-5”之间的全部实数，“0-5”只是这些数值组合的缩略表示。另外，当表述某个参数为≥2的整数，则相当于公开了该参数为例如整数2、3、4、5、6、7、8、9、10、11、12等。
在本文的描述中，需要说明的是，除非另有说明，“以上”、“以下”为包括本数，“一种或几种”中“几种”的含义是两种及两种以上。
如果没有特别的说明，本申请的所有实施方式以及可选实施方式可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有技术特征以及可选技术特征可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有步骤可以顺序进行，也可以随机进行，优选是顺序进行的。例如，所述方法包括步骤(a)和(b)，表示所述方法可包括顺序进行的步骤(a)和(b)，也可以包括顺序进行的步骤(b)和(a)。例如，所述提到所述方法还可包括步骤(c)，表示步骤(c)可以任意顺序加入到所述方法，例如，所述方法可以包括步骤(a)、(b)和(c)，也可包括步骤(a)、(c)和(b)，也可以包括步骤(c)、(a)和(b)等。
如果没有特别的说明，本申请所提到的“包括”和“包含”表示开放式，也可以是封闭式。例如，所述“包括”和“包含”可以表示还可以包括或包含没有列出的其他组分，也可以仅包括或包含列出的组分。
在本文的描述中，除非另有说明，术语“或(or)”是包括性的。也就是说，短语“A或(or)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)。除非另有说明，本申请中使用的术语具有本领域技术人员通常所理解的公知含义。除非另有说明，本申请中提到的各参数的数值可以用本领域常用的各种测量方法进行测量(例如，可以按照在本申请的实施例中给出的方法进行测试)。
相关技术中，多采用粘结剂丁苯橡胶和羧甲基纤维素钠制备负极极片，不能兼顾负极极片的加工性能和电芯的动力学性能。本申请的技术人员发现，这主要是因为采用在负极活性物质层中常规用量百分比为2％～2.5％的粘结剂丁苯橡胶和常规用量百分比为1％～2％的羟甲基纤维素钠制备的负极极片，该负极极片对应的电芯，在高功率体系下，动力学性能差；如果为了提高电芯的动力学性能，降低丁苯橡胶和羟甲基纤维素钠的加入量，则会出现负极浆料掉粘沉降、过滤性差、涂布颗粒划痕和负极极片粘结力差等一系列加工性能问题，从而进一步导致电芯的动力学性能恶化。
本申请提供的粘结剂，包括：内核材料，所述内核材料的玻璃化转变温度为-50℃～0℃；壳层材料，位于所述内核材料的至少部分表面上，所述壳层材料的玻璃化转变温度为60℃～100℃。
不希望限于任何理论，本申请的粘结剂，壳层材料位于内核材料的至少部分表面上，内核材料为玻璃化转变温度较低的柔软材料，壳层材料为玻璃化转变温度较高的坚硬材料，则粘结剂为内软外硬的核壳结构；柔软的内核材料利于负极极片冷压，有助于减少冷压压力，提升负极活性物质的压实密度窗口的最大值，并提供较好的粘结力，进而能够减少粘结剂用量，较少的粘结剂用量减少了对负极活性物质表面的包覆；相对坚硬的壳层材料在负极极片冷压后不会发生过度形变，降低了粘结剂对负极活性物质的包覆面积，有效减少锂离子嵌入和脱出时的阻抗，提升负极极片对应的电芯的动力学性能。如此上述粘结剂应用于电芯，电芯的直流内阻(DCR)降低5％～12％，充电窗口轻微提升；相比于传统技术中采用的丁苯橡胶，本申请中粘结剂的粘结力提升20％以上，无脱膜、掉粉，满充界面良好。
可理解，壳层材料可以包覆在内核材料的全部表面上，也可以只包覆在内核材料的部分表面上，优选壳层材料包覆在内核材料的全部表面上。极性基团可以包括羧基、羟基、羰基及酯基中的一种或多种。
上述提及的内核材料和壳层材料的玻璃化转变温度可以采用差示扫描量热仪(DSC)测试得到，具体方法如下：1.制样：称取1～3mg样品于Al坩埚中，盖上坩埚盖子；2. 参数设置：氮气气氛，吹扫气50Ml/min，保护气100Ml/min；3.温升程序：10℃/min，35℃～-30℃，-30℃保温3min；10℃/min，-30℃～50℃；4.读取DSC曲线中斜率最大处的温度即为玻璃化转变温度。
本申请实施例中，内核材料的玻璃化转变温度为-50℃～0℃；例如，可以为-50℃～-5℃、-50℃～-10℃、-50℃～-20℃、-50℃～-30℃、-50℃～-40℃、-30℃～-0℃或-30℃～-10℃等。壳层材料的玻璃化转变温度为60℃～100℃；例如，可以为60℃～95℃、65℃～90℃、70℃～85℃或70℃～80℃等。
本发明人经深入研究发现，当本申请的粘结剂在满足上述设计条件的基础上，若还可以满足下述条件中的一个或几个时，可以进一步改善电芯的动力学性能。
在其中一些实施例中，壳层材料具有极性基团。极性基团可以调节粘结剂在电解液中的溶胀能力，使得粘结剂在电解液中具有较高的溶胀特性，提升锂离子的传输通道，进一步提升电芯的动力学性能；壳层材料的极性基团可以提供氢键作用，进一步提升粘结剂对负极活性物质的粘结力，提高负极极片的加工性能。
在其中一些实施例中，内核材料可以包括苯乙烯单体单元-丁二烯单体单元的共聚物。
在其中一些实施例中，壳层材料可以包括苯乙烯单体单元-丁二烯单体单元-不饱和酸单体单元-不饱和酯单体单元的共聚物。
可理解，苯乙烯单体单元-丁二烯单体单元-不饱和酸单体单元-不饱和酯单体单元的共聚物，表示由苯乙烯单体单元、丁二烯单体单元、不饱和酸单体单元及不饱和酯单体单元共同构成的共聚物，共聚物中包括苯乙烯单体单元、丁二烯单体单元、不饱和酸单体单元及不饱和酯单体单元，并不限定共聚物中苯乙烯单体单元、丁二烯单体单元、不饱和酸单体单元及不饱和酯单体单元的排列顺序，共聚物中苯乙烯单体单元、丁二烯单体单元、不饱和酸单体单元及不饱和酯单体单元可以按照任何顺序排列。
可选地，不饱和酸单体单元对应的单体包括取代或未取代的含-C＝C-且碳原子数为3～6的不饱和酸。“取代或未取代”表示不饱和酸可以被取代，也可以不被取代。当所定义的不饱和酸被取代时，应理解为任选被本领域可接受的基团所取代，包括但不限于：硅烷基、羰基、烷氧基羰基、芳氧基羰基、氨基甲酰基、卤甲酰基、甲酰基、氰基、异氰基、异氰酸酯基、硫氰酸酯基、异硫氰酸酯基、羟基、三氟甲基、硝基或卤素，且上述基团也可以进一步被本领域可接受取代基取代。进一步可选地，不饱和酸单体单元对 应的单体包括丙烯酸、甲基丙烯酸、马来酸、富马酸及衣康酸中的一种或多种。
可选地，不饱和酯单体单元对应的单体包括取代或未取代的含-C＝C-的不饱和酯。“取代或未取代”表示不饱和酸可以被取代，也可以不被取代。当所定义的不饱和酸被取代时，应理解为任选被本领域可接受的基团所取代，包括但不限于：硅烷基、羰基、烷氧基羰基、芳氧基羰基、氨基甲酰基、卤甲酰基、甲酰基、氰基、异氰基、异氰酸酯基、硫氰酸酯基、异硫氰酸酯基、羟基、三氟甲基、硝基或卤素，且上述基团也可以进一步被本领域可接受取代基取代。进一步可选地，不饱和酯单体单元对应的单体包括甲基丙烯酸甲酯、乙基已酯、乙酸乙烯酯、丙烯酸异辛酯、丙烯酸羟乙酯、甲基丙烯酸异冰片酯、叔碳酸乙烯酯、丙烯酸丁酯、丙烯氰、丙烯酸乙酯、丙烯酸正丁酯及丙烯酸异丁酯中的一种或多种。
在其中一些实施例中，在25℃时，所述粘结剂的水溶液的固含量为45％时的粘度为10mPa·s～200mPa·s；例如，可以为10mPa·s～150mPa·s、20mPa·s～150mPa·s、50mPa·s～100mPa·s或80mPa·s～100mPa·s等。
上述提及的在25℃时，粘结剂的水溶液的固含量为45％时的粘度可以采用下述方法进行测定：称取500g固含量为45％的待测粘结剂的水溶液，搅拌2h以使待测粘结剂完全稳定均匀后进行测定。检测温度：25±1℃；采用转子及转速：63#转子，12r/min，取第6min数值；设备型号：DV-2TLV博勒飞粘度计。在其中一些实施方式中，粘结剂的体积平均粒径Dv50为100nm～1000nm；例如，可以为100nm～900nm、200nm～900nm、300nm～600nm、400nm～600nm或500nm～600nm等。
上述提及的体积平均粒径Dv50指的是在体积累计分布中50％所对应的粒度尺寸。作为示例，Dv50可以参照GB/T 19077-2016粒度分布激光衍射法，采用激光粒度分析仪方便地测定，如英国马尔文仪器有限公司的Mastersizer 2000E型激光粒度分析仪。
本申请实施方式还提供了一种上述的粘结剂的制备方法，包括如下步骤：
S11、苯乙烯单体与丁二烯单体发生聚合反应，制备所述内核材料；
S12、苯乙烯单体、丁二烯单体、不饱和酸类单体与不饱和酯类单体在所述内核材料的表面发生聚合反应。
在其中一些实施例中，制备内核材料的聚合反应中，苯乙烯单体和丁二烯单体的质量比为10:(4～8)；例如，可以为10:(4～7)、10:(5～8)或10:(5～6)等。
在其中一些实施例中，制备壳层材料的聚合反应中，苯乙烯单体、丁二烯单体、不 饱和酸单体和不饱和酯单体的质量比为10:(4～8):(1～3):(2～4)；例如，可以为10:(4～7):(2～3):(2～3)或10:(5～8):(1～2):(2～3)等。
在本申请的实施例中制备内核材料的聚合反应中和制备壳层材料的聚合反应中，均需要乳化剂和引发剂参与。
可选地，乳化剂可以包括烷基硫酸钠、烷基磺酸钠、烷基二苯醚二磺酸钠、烷基酚醚硫酸铵、烷基酚醚磺基琥珀酸酯钠盐、对苯乙烯磺酸钠、2-丙烯酰胺-2,2二甲基乙磺酸钠、烯丙基琥珀酸烷基酯磺酸钠、丙烯酰胺基异丙基磺酸钠以及烷基丙烯酸-2-乙磺酸钠盐中的一种或多种。
可选地，引发剂可以包括过硫酸钠、过硫酸铵以及过硫酸钾中的一种或多种。
本申请实施例还提供了一种粘结剂组合物，包括上述的粘结剂或者上述的方法制备的粘结剂及高粘度羧甲基纤维素钠，在25℃时，高粘度羧甲基纤维素钠的水溶液的固含量为1％时的粘度为10000mPa·s～20000mPa·s；例如，可以为10000mPa·s～19000mPa·s、10000mPa·s～15000mPa·s、13000mPa·s～17000mPa·s或15000mPa·s～20000mPa·s等。
传统技术中，负极极片使用的羧甲基纤维素钠，其固含量为1％的水溶液在25℃时的粘度为2000mPa·s～8000mPa·s，而上述提及的固含量为1％的高粘度羧甲基纤维素钠的水溶液在25℃时的粘度大幅度提高；采用高粘度羧甲基纤维素钠，在保证负极极片的加工性能的前提下可以适当降低用量，减少对负极活性物质表面的包覆，降低锂离子的迁移阻抗，提升负极极片对应的电芯的动力学性能。
上述提及的在25℃时，高粘度羧甲基纤维素钠的水溶液的固含量为1％时的粘度可以采用下述方法进行测定：称取干重5.0g的待测高粘度羧甲基纤维素钠，加入纯水至待测高粘度羧甲基纤维素钠和纯水的总重量为500g，搅拌溶解2h以使待测高粘度羧甲基纤维素钠完全分散均匀后进行测定，根据不同转子对应不同的粘度。检测温度：25±1℃；采用转子及转速：63#转子，12r/min，取第6min数值；设备型号：DV-2TLV博勒飞粘度计。
在其中一些实施例中，粘结剂与高粘度羧甲基纤维素钠的质量比为(1.1～3.5):1；例如，可以为(1.1～3):1、(1.6～2.6):1、(1.8～2.2):1或(2～2.2)等。经技术人员研究发现，当粘结剂和高粘度羧甲基纤维素钠的质量比在该范围内时，利于进一步提升粘结剂组合物的粘结力。
在其中一些实施例中，高粘度羧甲基纤维素钠中羟基上的氢原子被取代剂取代，取 代剂与羟基反应生成半缩醛。通过将高粘度羧甲基纤维素钠中羟基上的氢原子被取代剂取代，高粘度羧甲基纤维素钠暂时失去亲水性，避免高粘度羧甲基纤维素钠在接触水时立即发生抱团现象，利于实现高粘度羧甲基纤维素钠在水中的快速分散。同时半缩醛在溶解于水的过程中能够发生水解，重新生成羟基，恢复亲水性。
可选地，取代剂可以包括二醛类单体；进一步可选地，二醛类单体可以包括乙二醛及戊二醛中的一种或两种。
本申请实施例还提供了一种高粘度羧甲基纤维素钠的制备方法，包括如下步骤：
S201、使棉纤维与碱化剂在乙醇和水的混合溶液中，发生碱化反应。
在其中一些实施例中，水和棉纤维的质量比为(0.3～0.8):1，例如可以为(0.3～0.7):1、(0.4～0.6):1或(0.5～0.7):1等。乙醇和棉纤维的质量比为(1.0～2.0):1，例如可以为(1.0～1.8):1、(1.1～1.7):1、(1.3～1.6):1或(1.4～1.5):1等。碱化剂可以为质量百分比浓度为30％-55％的氢氧化钠水溶液；碱化剂和棉纤维的质量比为(0.6～1.0):1，例如可以为(0.6～0.9):1、(0.7～1.0):1或(0.7～0.8):1等。碱化反应的时间可以为30min～80min，碱化反应的温度可以为10℃～40℃。
S202、在碱化反应结束后，向反应体系中加入醚化剂，发生醚化反应；
在其中一些实施例中，醚化剂可以为质量百分比浓度为50％～80％的氯乙酸的乙醇溶液。醚化剂和棉纤维的质量比为(1.0～1.5):1，例如可以为(1.0～1.4):1或(1.2～1.3):1、等。醚化反应的时间可以为40min～70min，醚化反应的温度可以为60℃～90℃。
S203、使醚化反应的产物与取代剂发生取代反应，制得所述高粘度羧甲基纤维素；
可选地，所述取代剂包括二醛类单体；进一步可选地，所述二醛类单体包括乙二醛及戊二醛中的一种或两种。
在其中一些实施例中，醚化反应的产物与取代剂的质量比为100:(0.2～1.0)；例如，可以为100:(0.2～0.8)、100:(0.3～0.7)或100:(0.4～0.6)等。
在其中一些实施例中，取代反应的温度为30℃～70℃；例如，可以为30℃～60℃、40℃～70℃或50℃～60℃等。
在其中一些实施例中，取代反应的时间为20min～120min；例如，可以为20min～110min、30min～90min、40min～70min或50min～60min等。
本申请实施例还提供了一种负极浆料，包括上述的粘结剂、上述的方法制备的粘结剂或上述的粘结剂组合物。
本申请实施例还提供了一种负极浆料的制备方法，负极浆料包含粘结剂组合物，制备方法包括如下步骤：
S21、将负极活性物质、一部分所述高粘度羧甲基纤维素钠、导电剂及一部分溶剂，制得负极活性物质团聚物；
S22、向所述负极活性物质团聚物中加入剩余部分所述高粘度羧甲基纤维素钠、剩余部分溶剂及所述粘结剂，制得所述负极浆料。
本申请的实施例制备负极浆料时，高粘度羧甲基纤维素钠分两次加入，首先加入一部分高粘度羧甲基纤维素钠浸润负极活性物质，促进负极活性物质在水系浆料中分散均匀，再进行搅拌捏合得到负极活性物质团聚物，最后加入剩余部分高粘度羧甲基纤维素钠对负极活性物质进行搅拌，高粘度羧甲基纤维素钠可使负极活性物质悬浮分散。可理解，由于高粘度羧甲基纤维素钠在水中可快速分散，相对于传统负极浆料中采用的羧甲基纤维素钠，能够减少搅拌时间，满足2h负极搅拌制浆工艺，提高搅拌产能。
在其中一些实施例中，高粘度羧甲基纤维素钠分两次加入，第一次加入的高粘度羧甲基纤维素钠和第二次加入的高粘度羧甲基纤维素钠的质量比为(0.25～1):1；例如，可以为(0.25～0.9):1、(0.3～0.8):1或(0.5～0.7):1等。
负极极片
本申请实施例还提供了一种负极极片，包括：
负极集流体；及
负极活性物质层，位于所述负极集流体的至少一个表面上；
其中，所述负极活性物质层包括上述的粘结剂、上述的方法制备的负极粘结剂或上述的粘结剂组合物。
在其中一些实施例中，粘结剂在负极活性物质层中的质量占比为1.3％～2.1％，可选为1.5％～2.1％，进一步可选为1.8％～2.1％。负极活性物质层中粘结剂的用量明显低于传统技术中粘结剂丁苯橡胶的用量。
上述提及的粘结剂在负极活性物质层中的质量占比可以采用如下方法测得：首先测定负极活性物质层中粘结剂的质量M1，然后测定负极活性物质层的质量M0，基于公式M1/M0*100％计算得到粘结剂在负极活性物质层中的质量占比。
在其中一些实施例中，负极活性物质层包括上述的粘结剂组合物，高粘度羧甲基纤 维素钠在负极活性物质层中的质量占比为0.6％～1.2％，可选为0.8％～1.2％，进一步可选为0.9％～1.2％。传统技术中，采用的羧甲基纤维素钠在负极活性物质层中的质量占比通常为1％～2％，而本申请的实施例中高粘度羧甲基纤维素钠在负极活性物质层中的质量占比明显下降。
上述提及的高粘度羧甲基纤维素钠在负极活性物质层中的质量占比可以如下方法测得：首先测定负极活性物质层中高粘度羧甲基纤维素钠的质量M2，然后测定负极活性物质层的质量M0，基于公式M2/M0*100％计算得到高粘度羧甲基纤维素钠在负极活性物质层中的质量占比。
负极集流体可以采用常规金属箔片或复合集流体。作为示例，金属箔片可以采用铜箔。复合集流体可包括高分子材料基层和形成于高分子材料基材至少一个表面上的金属层。复合集流体可通过将金属材料(铜、铜合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(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)等的基材)上而形成。
负极活性物质层通常还包括负极活性物质、导电剂和其他可选助剂。
作为示例，负极活性物质可以包括以下材料中的至少一种：人造石墨、天然石墨、软炭、硬炭、硅基材料、锡基材料和钛酸锂等。硅基材料可选自单质硅、硅氧化合物、硅碳复合物、硅氮复合物以及硅合金中的至少一种。锡基材料可选自单质锡、锡氧化合物以及锡合金中的至少一种。但本申请并不限定于这些材料，还可以使用其他可被用作电池负极活性材料的传统材料。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
作为示例，导电剂可以为超导碳、乙炔黑、炭黑、科琴黑、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，其他可选助剂可以是PTC热敏电阻材料等。
作为示例，可以通过以下方式制备负极极片：将上述用于制备负极极片的组分，例如负极活性材料、导电剂、粘结剂和任意其他组分分散于溶剂(例如去离子水)中，形成负极浆料；将负极浆料涂覆在负极集流体上，经烘干、冷压等工序后，即可得到负极极片。
上述原料未特别说明的均可以通过市购获得。
二次电池
二次电池，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、本申请上述提供的负极极片、隔离膜及电解液。在电池充放电过程中，活性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，起到隔离的作用。电解液在正极极片和负极极片之间起到传导离子的作用。
正极极片
在二次电池中，正极极片通常包括正极集流体及设置在正极集流体至少一个表面上的正极膜层，正极膜层包括正极活性材料。
作为示例，正极集流体具有在其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相对的两个表面的其中任意一者或两者上。
作为示例，正极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可采用铝箔。复合集流体可包括高分子材料基层和形成于高分子材料基层至少一个表面上的金属层。复合集流体可通过将金属材料(铝、铝合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(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)等的基材)上而形成。
当二次电池为锂离子电池时，正极活性材料可采用本领域公知的用于锂离子电池的正极活性材料。作为示例，正极活性材料可包括以下材料中的至少一种：橄榄石结构的含锂磷酸盐、锂过渡金属氧化物及其各自的改性化合物。但本申请并不限定于这些材料，还可以使用其他可被用作电池正极活性材料的传统材料。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。其中，锂过渡金属氧化物的示例可包括但不限于锂钴氧化物(如LiCoO 2)、锂镍氧化物(如LiNiO 2)、锂锰氧化物(如LiMnO 2、LiMn 2O 4)、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(如LiNi 1/3Co 1/3Mn 1/3O 2(也可以简称为NCM 333)、LiNi 0.5Co 0.2Mn 0.3O 2(也可以简称为NCM 523)、LiNi 0.5Co 0.25Mn 0.25O 2(也可以简称为NCM 211)、LiNi 0.6Co 0.2Mn 0.2O 2(也可以简称为NCM 622)、LiNi 0.8Co 0.1Mn 0.1O 2(也可以简称为NCM 811)、锂镍钴铝氧化物(如LiNi 0.85Co 0.15Al 0.05O 2)及其改性化合物等中的至少一种。橄榄石结构的含锂磷酸盐的示例可包括但不限于磷酸铁锂(如LiFePO 4(也可以简称为LFP))、磷酸铁锂与碳的复合材料、磷酸锰锂(如LiMnPO 4)、磷酸锰锂与碳的复合材料、磷酸锰铁锂、磷酸锰铁 锂与碳的复合材料中的至少一种。
当二次电池为钠离子电池时，正极活性材料可采用本领域公知的用于钠离子电池的正极活性材料。作为示例，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。其中，正极活性物质可选自钠铁复合氧化物(NaFeO 2)、钠钴复合氧化物(NaCoO 2)、钠铬复合氧化物(NaCrO 2)、钠锰复合氧化物(NaMnO 2)、钠镍复合氧化物(NaNiO 2)、钠镍钛复合氧化物(NaNi 1/2Ti 1/2O 2)、钠镍锰复合氧化物(NaNi 1/2Mn 1/2O 2)、钠铁锰复合氧化物(Na 2/3Fe 1/3Mn 2/3O 2)、钠镍钴锰复合氧化物(NaNi 1/3Co 1/3Mn 1/3O 2)、钠铁磷酸化合物(NaFePO 4)、钠锰磷酸化合物(NaMn PO 4)、钠钴磷酸化合物(NaCoPO 4)、普鲁士蓝类材料、聚阴离子材料(磷酸盐、氟磷酸盐、焦磷酸盐、硫酸盐)等，但本申请并不限定于这些材料，本申请还可以使用其他可被用作钠离子电池正极活性物质的传统公知的材料。
所述正极膜层通常还可选地包括粘结剂、导电剂和其他可选助剂。
作为示例，所述粘结剂可以包括聚偏氟乙烯(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-六氟丙烯共聚物及含氟丙烯酸酯树脂中的至少一种。
作为示例，所述导电剂可以包括超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种
作为示例，可以通过以下方式制备正极极片：将上述用于制备正极极片的组分，例如正极活性材料、导电剂、粘结剂和任意其他的组分分散于溶剂(例如N-甲基吡咯烷酮)中，形成正极浆料；将正极浆料涂覆在正极集流体上，经烘干、冷压等工序后，即可得到正极极片。
隔离膜
在一些实施方式中，二次电池中还包括隔离膜。本申请对隔离膜的种类没有特别的限制，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，隔离膜的材质可选自玻璃纤维、无纺布、聚乙烯、聚丙烯及聚偏二氟乙烯中的至少一种。隔离膜可以是单层薄膜，也可以是多层复合薄膜，没有特别限制。在隔离膜为多层复合薄膜时，各层的材料可以相同或不同，没有特别限制。
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。
电解液
二次电池可以包括电解液，电解液在正极和负极之间起到传导离子的作用。电解液可以包括电解质盐和溶剂。
作为示例，电解质盐可选自六氟磷酸锂(LiPF 6)、四氟硼酸锂(LiBF 4)、高氯酸锂(LiClO 4)、六氟砷酸锂(LiAsF 6)、双氟磺酰亚胺锂(LiFSI)、双三氟甲磺酰亚胺锂(LiTFSI)、三氟甲磺酸锂(LiTFS)、二氟草酸硼酸锂(LiDFOB)、二草酸硼酸锂(LiBOB)、二氟磷酸锂(LiPO 2F 2)、二氟二草酸磷酸锂(LiDFOP)及四氟草酸磷酸锂(LiTFOP)中的一种或几种。
作为示例，所述溶剂可选自碳酸亚乙酯(EC)、碳酸亚丙酯(PC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)、碳酸二甲酯(DMC)、碳酸二丙酯(DPC)、碳酸甲丙酯(MPC)、碳酸乙丙酯(EPC)、碳酸亚丁酯(BC)、氟代碳酸亚乙酯(FEC)、甲酸甲酯(MF)、乙酸甲酯(MA)、乙酸乙酯(EA)、乙酸丙酯(PA)、丙酸甲酯(MP)、丙酸乙酯(EP)、丙酸丙酯(PP)、丁酸甲酯(MB)、丁酸乙酯(EB)、1,4-丁内酯(GBL)、环丁砜(SF)、二甲砜(MSM)、甲乙砜(EMS)及二乙砜(ESE)中的一种或几种。
在一些实施方式中，电解液中还包括添加剂。例如添加剂可以包括负极成膜添加剂，也可以包括正极成膜添加剂，还可以包括能够改善电池某些性能的添加剂，例如改善电池过充性能的添加剂、改善电池高温性能的添加剂、改善电池低温性能的添加剂等。
在一些实施方式中，本申请的二次电池为锂离子二次电池。
可以按照本领域常规方法制备二次电池，例如将正极极片、隔离膜、负极极片按顺序卷绕(或叠片)，使隔离膜处于正极极片与负极极片之间起到隔离的作用，得到电芯，将电芯置于外包装中，注入电解液并封口，得到二次电池。
本申请实施例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4是作为一个示例的方形结构的二次电池5。
在一些实施例中，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。
在一些实施例中，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，作为塑料，可列举出聚丙烯、聚对苯二甲酸丁二醇酯以及聚丁二酸丁二醇酯等。
在一些实施例中，参照图5，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能够盖设于所述开口，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多个，可根据需求来调节。
在一些实施例中，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6是作为一个示例的电池模块4。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。
在一些实施例中，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7和图8是作为一个示例的电池包1。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能够盖设于下箱体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
本申请还提供一种用电装置，所述用电装置包括所述的二次电池、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装置的电源，也可以作为所述装置的能量存储单元。所述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9是作为一个示例的用电装置6。该用电装置6为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了满足该装置对二次电池的高功率和高能量密度的需求，可以采用电池包或电池模块。
作为另一个示例的装置可以是手机、平板电脑、笔记本电脑等。该装置通常要求轻薄化，可以采用二次电池作为电源。
以下结合实施例进一步说明本申请的有益效果。
实施例
为了使本申请所解决的技术问题、技术方案及有益效果更加清楚，以下将结合实施例和附图进行进一步详细说明。显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。以下对至少一个示例性实施例的描述实际上仅仅是说明性的，决不作为对本申请及其应用的任何限制。基于本申请中的实施例，本领域普通技术人员在没有付出创造性劳动前提下所获得的所有其他实施例都属于本申请保护的范围。
本申请的实施例中所用的材料均可以通过商购获得。
一、粘结剂的制备
实施例1：
该粘结剂包括内核材料和包覆在内核材料表面的壳层材料。内核材料的玻璃化转变温度为-30℃，壳层材料的玻璃化转变温度为80℃，固含量为1％的粘结剂的水溶液在25℃时的粘度为100mPa·s，该粘结剂的体积平均粒径Dv50为500nm。具体地，制备方法如下：
1)向反应釜中加入110g水、0.65g引发剂、1.5g乳化剂，然后加入50g苯乙烯和25g丁二烯，调节pH值至5，将反应釜升温至70℃，反应40min，制得含有内核材料的核层乳液；
2)向反应釜中滴加50g苯乙烯、25g丁二烯、10g甲基丙烯酸和15g甲基丙烯酸甲酯，滴加1.5g乳化剂、0.65g引发剂和110g去离子水，充分搅拌1.5h后，将反应釜升温至80℃，搅拌反应6h后冷却收料，制得含有粘结剂的乳液。
实施例2-14：
实施例2-14与实施例1基本相同，区别在于：制备内核材料时采用单体的种类和/或用量、制备壳层材料时采用单体的种类和/或用量、内核材料的玻璃化转变温度、壳层材料的玻璃化转变温度、固含量为1％的粘结剂的水溶液在25℃时的粘度、粘结剂的体积平均粒径Dv50这些参数中的至少一种不相同，具体如下表1所示。
其中，实施2-3中进一步调整了步骤1)中的反应釜pH值、反应釜温度及反应时间 和/或步骤2)中的反应釜温度；
具体地，实施例2中的步骤1)中的反应釜pH值为4.5，反应釜温度为60℃，反应时间为50min；步骤2)中的反应釜温度为85℃。
具体地，实施例3中的步骤1)中的反应釜pH值为5.5，反应釜温度为80℃，反应时间为30min；步骤2)中的反应釜温度为83℃。
对比例1
对比例1中仅制备内核材料，按照实施例1中步骤1)相同的制备方法，得到对比例1的粘结剂。
对比例2
对比例2中直接制备壳层材料，按照实施例1中步骤2)相同的制备方法，得到对比例2的粘结剂。
对比例3-4
对比例3-4与实施例1基本相同，区别仅在于：制备壳层材料时采用单体的用量不同，具体如下表1所示。
粘结剂性能测试
计算实施例1～14和对比例1～4中的含有粘结剂的乳液的固含量，具体方法为：计算制备过程中加入的除去离子水之外的所有物料的总质量W1，计算制备过程中加入的包括去离子水在内的所有物料的总质量W2，根据公式W1/W2*100％，计算乳液中含有的粘结剂的固含量。
测试对实施例1～14和对比例1～4中的粘结剂的内核材料玻璃化转变温度、壳层材料玻璃化转变温度、固含量为1％的粘结剂的水溶液在25℃时的粘度及体积平均粒径Dv50，Dv50表示粘结剂累计体积分布百分数达到50％时所对应的粒径。测试方法分别如下：
内核材料玻璃化转变温度：采用差示扫描量热仪(DSC)测试内核材料的玻璃化转变温度，具体过程如下：1.制样：称取1～3mg内核材料于Al坩埚中，盖上坩埚盖子；2.参数设置：氮气气氛，吹扫气50Ml/min，保护气100Ml/min；3.温升程序：10℃/min，35℃～-30℃，-30℃保温3min；10℃/min，-30℃～50℃；4.读取DSC曲线中斜率最大处的温度即为内核材料的玻璃化转变温度。
壳层材料玻璃化转变温度：采用差示扫描量热仪(DSC)测试内核材料的玻璃化转 变温度，具体过程如下：1.制样：称取1～3mg内核材料于Al坩埚中，盖上坩埚盖子；2.参数设置：氮气气氛，吹扫气50Ml/min，保护气100Ml/min；3.温升程序：10℃/min，35℃～-30℃，-30℃保温3min；10℃/min，-30℃～50℃；4.读取DSC曲线中斜率最大处的温度即为壳层材料的玻璃化转变温度。
含有粘结剂的乳液在25℃时的粘度：称取500g的待测粘结剂的乳液，搅拌溶解2h以使待测粘结剂完全稳定均匀后进行测定。检测温度：25±1℃；采用转子及转速：63#转子，12r/min，取第6min数值；设备型号：DV-2TLV博勒飞粘度计。
体积平均粒径Dv50：参照GB/T 19077-2016粒度分布激光衍射法，采用激光粒度分析仪(如Mastersizer 2000E型激光粒度分析仪)进行测定。
实施例1～14和对比例1～4制得的粘结剂的部分参数及制备内核材料时采用的单体种类及用量、制备壳层材料时采用的单体种类及用量如下表1所示。
表1
Figure PCTCN2022104329-appb-000001
Figure PCTCN2022104329-appb-000002
其中：表1中Tg1表示内核材料的玻璃化转变温度，Tg2表示壳层材料的玻璃化转变温度。粘度是指固含量为1％的粘结剂的水溶液在25℃时的粘度
二、高粘度羧甲基纤维素钠的制备
实施例15：
1)对棉纤维进行破碎处理，将破碎处理后的棉纤维与乙醇和水混合，投入反应器中，加入氢氧化钠水溶液，投料结束后，排除反应器内的空气，使反应器的真空度达到-0.08MPa，将惰性气体充入反应器内，使反应器内部压力大于0.02MPa，重复抽真空、充惰性气体的操作2～3次，排空反应器内的空气，搅拌碱化70min，碱化温度为30℃；其中，水和棉纤维的质量比为0.5:1，乙醇和棉纤维的质量比为1.5:1，氢氧化钠水溶液的质量百分比浓度为40％，氢氧化钠水溶液和棉纤维的质量比为0.8:1；
2)将氯乙酸的乙醇溶液均匀喷淋至反应器内，排除反应器内的空气，使反应器的真空度达到-0.08MPa，将惰性气体充入反应器内，使反应器内部压力大于0.02MPa，将反应器的温度升高至80℃，醚化反应50min；其中，氯乙酸的乙醇溶液的质量百分比浓度为70％，氯乙酸的乙醇溶液和棉纤维的质量比为1.2:1；
3)醚化反应结束后冷却至50℃，将物料加入到体积浓度为60％的酒精中，用盐酸调节pH至中性，经过两次洗涤，两次离心，物料进入真空耙式干燥机干燥，经测物料含湿量为33％。均匀喷淋加入乙二醛的酒精溶液，所使用的酒精是体积浓度为65％的酒精，控制温度在55℃进行取代反应60min，同时在真空负压(-0.02MPa)下回收剩余酒精，经过烘干、粉碎等后处理，得到高粘度羧甲基纤维素钠；其中，醚化反应后产物与乙二醛的质量比为100:0.6。
实施例16-20
实施例16-20与实施例15基本相同，区别在于：步骤1)中的乙醇的用量、水的用量、氢氧化钠水溶液的浓度、氢氧化钠水溶液的用量、碱化反应的时间、简化反应的温度；和/或步骤2)中氯乙酸的乙醇溶液的浓度、氯乙酸的乙醇溶液的用量、醚化反应的时间、醚化反应的温度；和/或步骤3)中的取代剂的种类/或用量、取代反应的时间、取 代反应的温度中的至少一种不相同，具体如下表2所示。
实施例21
实施例21与实施例15的区别在于：仅进行了碱化反应和醚化反应，未进行取代反应，碱化反应按照实施例15中步骤1)相同的碱化方法，醚化反应按照实施例15中步骤2)相同的醚化方法。具体如下表2所示。
高粘度羧甲基纤维素钠性能测试
测试实施例15～21中的高粘度羧甲基纤维素钠在25℃时且固含量为1％的水溶液的粘度。测试方法如下：
称取干重5.0g的待测高粘度羧甲基纤维素钠，加入纯水至待测高粘度羧甲基纤维素钠和纯水的总重量为500g，搅拌溶解2h以使待测高粘度羧甲基纤维素钠完全分散均匀后进行测定，根据不同转子对应不同的粘度。检测温度：25±1℃；采用转子及转速：63#转子，12r/min，取第6min数值；设备型号：DV-2TLV博勒飞粘度计。
实施例15～20和对比例5～6制得的高粘度羧甲基纤维素钠的粘度及制备过程中用量与参数设置如下表2所示。
表2
Figure PCTCN2022104329-appb-000003
其中：表2中粘度是指高粘度羧甲基纤维素钠在25℃时且固含量为1％的水溶液的粘度。
二、负极浆料的制备
实施例22：
将95.9g的负极活性物质石墨、0.16g的实施例15中制得的高粘度羧甲基纤维素钠、2.0g的导电剂碳黑(SP)以200rpm混合15min，搅拌均匀，加入43.54g的去离子水，按照转速300rpm搅拌捏合60min，得到浸润良好的石墨团聚物；再加入0.64g高粘度羧甲基纤维素钠，按照转速300rpm搅拌5min，再加入43.54g去离子水后以1200rpm转速分散60min，再加入2.89g实施例1中制得的含有粘结剂的乳液，以800rpm搅拌30min，得到负极浆料。
实施例23-32和实施例34-56
实施例23-32和实施例34-56与实施例21基本相同，区别仅在于：负极活性物质用量、粘结剂种类和/或用量及高粘度羧甲基纤维素钠种类和/或用量中的至少一项不同，具体如下表3所示。
实施例33
实施例33与实施例22的区别在于：采用2h搅拌工艺，制备过程具体如下：
将95.9g的负极活性物质石墨、0.16g的高粘度羧甲基纤维素钠、2.0g的导电剂碳黑以200rpm混合5min，搅拌均匀，加入43.54g的去离子水，按照转速800rpm搅拌捏合30min，得到浸润良好的石墨团聚物；再加入0.64g高粘度羧甲基纤维素钠，按照转速300rpm搅拌5min，再加入43.54g去离子水后以1200rpm转速分散50min，再加入4.0g含有粘结剂的乳液，以800rpm搅拌30min，得到负极浆料；其中，含有粘结剂的乳液的固含量为45％。
对比例7-11
对比例7-11与实施例22基本相同，区别仅在于：负极活性物质用量、粘结剂种类和/或用量及高粘度羧甲基纤维素钠种类和/或用量中的至少一项不同，具体如下表3所示。
负极浆料性能测试
对实施例22-56及对比例7-11中制备的负极浆料进行浆料稳定性测试，具体测试过程如下：
在25℃下，将负极浆料出货粘度符合涂布规格3000-20000mPa.s后，取出500mL浆料静置，每4h测试负极浆料粘度，每12h用钢板刮测浆料底部主材沉降量，测完24h停止。
实施例23中负极浆料的粘度-时间曲线如图1所述，图1中横坐标为测试时间，纵坐标为负极浆料的粘度值。由图1可知，将负极浆料静置24h时，负极浆料的粘度几乎不变，表明负极浆料的粘度稳定性良好。
实施例22-56对比例7-11中负极浆料制备过程中的参数设置及浆料稳定性测试结果如表3所示。
表3
Figure PCTCN2022104329-appb-000004
Figure PCTCN2022104329-appb-000005
其中：表3中高粘CMC表示高粘度羧甲基纤维素钠，常规CMC表示常规羧甲基纤维素钠。常规工艺是指实施例22中采用的负极浆料制备工艺，2h搅拌工艺是指实施例33中采用的负极浆料制备工艺。常规CMC的粘度为5000mPa·s。
三、负极极片的制备
将实施例22-56及对比例7-11中的负极浆料分别均匀涂覆于负极集流体铜箔上，单面重量控制在60～80mg/1540.25mm 2，之后经过烘干、冷压、分切，得到负极极片。
负极极片性能测试
对实施例22-56及对比例7-11中的负极极片分别进行极片粘结力测试，粘结力测试结果如下表4所示。具体测试方法如下：
在25℃下，将负极极片取为待测试极片，用刀片截取宽度为30mm、长度为100～160mm的极片试样，将专用双面胶贴于钢板上，胶带宽度为20mm、长度为90-150mm，将截取的极片试样贴在双面胶上，测试面朝下，后用压辊沿同一个方向滚压三次，将宽度与极片试样等宽，长度大于极片试样长度80～200mm的纸带插入极片试样下方，并且用皱纹胶固定，打开拉力机电源，指示灯亮，调整限位块到合适位置，将钢板未贴极片试样的一端用下夹具固定，将纸带向上翻折，用上夹具固定，利用拉力机附带的手动控制器上的“上行”和“下行”按钮调整上夹具的位置，打开与拉力机链接的专用电脑，双击桌面软件图标，进行测试，拉伸速率为50m/min，测试距离为50mm，软件每10s取一个数据点。
平行测定三次实施例23中负极极片的粘结力，实施例23中负极极片的粘结力-时间曲线如图2所示，纵坐标为粘结力，横坐标为测试距离。由图2可知，三次测定实施例23中负极极片的粘结力的平均值高于15N/m，表明负极极片的粘结力良好。
四、电芯的制备
1、正极极片的制备：将正极活性材料LiNi 0.8Co 0.1Mn 0.1O 2(NCM811)、粘结剂聚偏氟乙烯(PVDF)、导电剂乙炔黑按照质量比为97％:1.5％:1.5％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。
2、隔离膜：以厚度为12μm的聚乙烯膜(PE)作为隔离膜。
3、电解液的制备：将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按体积比1:1:1混合，然后将LiPF6均匀溶解在上述溶液中，得到电解液。该电解液中，LiPF 6的浓度为1mol/L。
4、电芯的制备：将上述正极极片、隔离膜、实施例22-56及对比例7-11中制备的负极极片及隔离液组装成小软包电芯。
电芯性能测试
对实施例22-56及对比例7-11制备的电芯进行电池直流阻抗测试，具体测试过程如下：
在25℃下，将实施例1对应的电池，以1C恒流充电至4.2V，再以4.2V恒定电压充电至电流为0.05C，搁置5min后，以1C恒流放电12min，记录电压V1。搁置5min后，在-10℃下放置2h，然后再以15C放电10s，记录电压V2，则(V2-V1)/15C，得 到电芯的DCR。
以对比例7中电芯的DCR为基准，计算实施例22-56及对比例7-11中电芯的电芯内阻增大比率，以实施例22为例，实施例22的电芯内阻增大比率＝DCR(实施例22)/DCR(对比例7)*100％，其他实施例的电芯内阻增大比率计算方法同上。实施例22-56及对比例7-11中电芯的电芯内阻增大比率结果如下表4所示。
图3为实施例24、实施例25、实施例26及对比例7的电芯的放电DCR柱状图。由图3可知，电芯的DCR降低明显，表明电芯的动力学性能明显改善。
实施例22-56及对比例7-11的负极极片性能测试结果和电芯性能测试结果如下表4所示。
表4
Figure PCTCN2022104329-appb-000006
Figure PCTCN2022104329-appb-000007
其中，表4中负极扣重是指负极极片单位面积内的重量。
由表1中实施例1和对比例3-4可知，通过优化制备粘结剂壳层材料时采用的不饱和酸单体和不饱和酯单体的用量，可使壳层材料的玻璃化转变温度落在粘结剂的需求范围内。
由表1-4中实施例39和对比例7-11可知，负极极片的负极活性物质层中通过设置本发明实施例的粘结剂，可以提高负极极片的极片粘结剂力，满足负极极片的加工性能；同时还可以降低电芯的直流内阻，从而提升电芯的动力学性能。
由实施例22-38及实施例40-56可知，负极极片的负极活性物质层中通过同时设置本发明实施例的粘结剂和高粘度羧甲基纤维素钠，可以进一步提高负极极片的极片粘结力，满足负极极片的加工性能；同时进一步降低电芯的直流内阻，提升电芯的动力学性能。尤其是，通过进一步优化本发明实施例的粘结剂和高粘度羧甲基纤维素钠在负极活性物质层中的用量，能够获得更高的极片粘结力和更低的电芯直流内阻。
实施例22-25及实施例35-36的区别在于：负极活性物质层中粘结剂的质量占比不同；优选，当粘结剂的质量占比为1.3％～2.1％时，负极极片加工性能良好，同时电芯动力学性能优异；更优选，粘结剂的质量占比为1.5％～2.1％；进一步优选，粘结剂的质量占比为7.8％～2.1％。
实施例26～33及实施例37-38的区别在于：负极活性物质层中高粘度羧甲基纤维素钠的质量占比不同；优选，当高粘度羧甲基纤维素钠的质量占比为0.6％～1.0％，负极极片加工性能良好，同时电芯动力学性能优异；更优选地，高粘度羧甲基纤维素钠的质量占比为0.6％～1.0％时；进一步优选，高粘度羧甲基纤维素钠的质量占比为0.9％～1.0％。
实施例24和实施例33的区别在于：搅拌工艺不同，采用本发明实施例的粘结剂和高粘度羧甲基纤维素钠制备负极浆料，能够满足2h负极搅拌制浆工艺，提高搅拌产能。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到各种等效的修改或替换，这些修改或替换都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应 以权利要求的保护范围为准。

Claims (25)

  1. 一种粘结剂，包括：
    内核材料，所述内核材料的玻璃化转变温度为-50℃～0℃；
    壳层材料，位于所述内核材料的至少部分表面上，所述壳层材料的玻璃化转变温度为60℃～100℃。
  2. 如权利要求1所述的粘结剂，其中，所述壳层材料具有极性基团。
  3. 如权利要求1至2所述的粘结剂，其中，所述内核材料包括苯乙烯单体单元-丁二烯单体单元的共聚物。
  4. 如权利要求1至3任一项所述的粘结剂，其中，所述壳层材料包括苯乙烯单体单元-丁二烯单体单元-不饱和酸单体单元-不饱和酯单体单元的共聚物。
  5. 如权利要求4所述的粘结剂，其中，所述不饱和酸单体单元对应的单体包括取代或未取代的含-C＝C-且碳原子数为3～6的不饱和酸；
    可选地，所述不饱和酸单体单元对应的单体包括丙烯酸、甲基丙烯酸、马来酸、富马酸及衣康酸中的一种或多种。
  6. 如权利要求4至5任一项所述的粘结剂，其中，所述不饱和酯单体单元对应的单体包括取代或未取代的含-C＝C-的不饱和酯；
    可选地，所述不饱和酯单体单元对应的单体包括甲基丙烯酸甲酯、乙基已酯、乙酸乙烯酯、丙烯酸异辛酯、丙烯酸羟乙酯、甲基丙烯酸异冰片酯、叔碳酸乙烯酯、丙烯酸丁酯、丙烯氰、丙烯酸乙酯、丙烯酸正丁酯及丙烯酸异丁酯中的一种或多种。
  7. 如权利要求1至6任一项所述的粘结剂，其中，在25℃时，所述粘结剂的水溶液的固含量为45％时的粘度为10mPa·s～200mPa·s。
  8. 如权利要求1至7任一项所述的粘结剂，其中，所述粘结剂的体积平均粒径Dv50为100nm～1000nm。
  9. 一种权利要求4至8任一项所述的粘结剂的制备方法，包括如下步骤：
    S11、苯乙烯单体与丁二烯单体发生聚合反应，制备所述内核材料；
    S12、苯乙烯单体、丁二烯单体、不饱和酸类单体与不饱和酯类单体在所述内核材料的表面发生聚合反应。
  10. 如权利要求9所述的粘结剂的制备方法，其中，制备所述内核材料的聚合反应中，所述苯乙烯单体和所述丁二烯单体的质量比为10:(4～8)。
  11. 如权利要求9至10任一项所述的粘结剂的制备方法，其中，制备所述壳层材料的 聚合反应中，所述苯乙烯单体、所述丁二烯单体、所述不饱和酸单体和所述不饱和酯单体的质量比为10:(4～8):(1～3):(2～4)。
  12. 一种粘结剂组合物，包括权利要求1至8任一项所述的粘结剂或者包括权利要求9至11任一项所述的方法制备的粘结剂及高粘度羧甲基纤维素钠，在25℃时所述高粘度羧甲基纤维素钠的水溶液的固含量为1％时的粘度为10000mPa·s～20000mPa·s。
  13. 如权利要求12所述的粘结剂组合物，其中，所述粘结剂与所述高粘度羧甲基纤维素钠的质量比为(1.1～3.5):1。
  14. 如权利要求12至13任一项所述的粘结剂组合物，其中，所述高粘度羧甲基纤维素钠中羟基上的氢原子被取代剂取代，所述取代剂与所述羟基反应生成半缩醛；
    可选地，所述取代剂包括二醛类单体；进一步可选地，所述二醛类单体包括乙二醛及戊二醛中的一种或两种。
  15. 一种负极浆料，包括权利要求1至8任一项所述的粘结剂、权利要求9至11任一项所述的方法制备的粘结剂或权利要求12至14任一项所述的粘结剂组合物。
  16. 一种权利要求15所述的负极浆料的制备方法，所述负极浆料包含所述粘结剂组合物，所述制备方法包括如下步骤：
    S21、将负极活性物质、一部分所述高粘度羧甲基纤维素钠、导电剂及一部分溶剂，制得负极活性物质团聚物；
    S22、向所述负极活性物质团聚物中加入剩余部分所述高粘度羧甲基纤维素钠、剩余部分溶剂及所述粘结剂，制得所述负极浆料。
  17. 如权利要求16所述的负极浆料的制备方法，其中，还包括制备所述高粘度羧甲基纤维素钠的步骤，其包括：
    S201、使棉纤维与碱化剂在乙醇和水的混合溶液中，发生碱化反应；
    S202、在碱化反应结束后，向反应体系中加入醚化剂，发生醚化反应；
    S203、使醚化反应的产物与取代剂发生取代反应，制得所述高粘度羧甲基纤维素钠；
    可选地，所述取代剂包括二醛类单体；进一步可选地，所述二醛类单体包括乙二醛及戊二醛中的一种或两种。
  18. 如权利要求17所述的负极浆料的制备方法，其中，步骤S203满足下述Ⅰ～Ⅲ中的至少一个条件：
    Ⅰ、所述醚化反应的产物与所述取代剂的质量比为：100:(0.2～1.0)；
    Ⅱ、所述取代反应的温度为30℃～70℃；
    Ⅲ、所述取代反应的时间为20min～120min。
  19. 一种负极极片，包括：
    负极集流体；及
    负极活性物质层，位于所述负极集流体的至少一个表面上；
    其中，所述负极活性物质层包括权利要求1至8任一项所述的粘结剂、权利要求9至11任一项所述的方法制备的负极粘结剂或权利要求12至14任一项所述的粘结剂组合物。
  20. 如权利要求19所述的负极极片，其中，所述粘结剂在所述负极活性物质层中的质量占比为1.3％～2.1％，可选为1.5％～2.1％，进一步可选为1.8％～2.1％。
  21. 如权利要求19至20所述的负极极片，其中，所述负极活性物质层包括权利要求12至14任一项所述的粘结剂组合物，所述高粘度羧甲基纤维素钠在所述负极活性物质层中的质量占比为0.6％～1.2％，可选为0.8％～1.2％，进一步可选为0.9％～1.2％。
  22. 一种二次电池，包括权利要求19至21任一项所述的负极极片。
  23. 一种电池模块，包括权利要求22所述的二次电池。
  24. 一种电池包，包括权利要求23所述的电池模块。
  25. 一种用电装置，包括权利要求22所述的二次电池、权利要求23所述的电池模块或权利要求24所述的电池包中的至少一种。
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Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP7808131B2 (ja) * 2023-04-07 2026-01-28 香港時代新能源科技有限公司 二次電池用バインダー及びその製造方法、及びセパレータ、電池セル、電池及び電力消費装置
CN119307207A (zh) * 2024-12-16 2025-01-14 峻益天材(深圳)新能源有限公司 负极粘结剂、负极极片和电化学储能器件
CN119764566B (zh) * 2024-12-27 2026-04-21 中创新航科技集团股份有限公司 一种锂离子电池
CN119955443B (zh) * 2025-04-09 2025-08-01 深圳好电科技有限公司 一种正极粘结剂、正极组合物、正极片及电池
CN121343519A (zh) * 2025-12-18 2026-01-16 深圳好电科技有限公司 一种负极粘结剂、电极片及电池

Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030113626A1 (en) * 1997-03-04 2003-06-19 Nippon Zeon Co., Ltd. Binder for battery, slurry for battery electrode, electrode for lithium secondary battery, and lithium secondary battery
CN103173161A (zh) * 2013-03-08 2013-06-26 东莞新能源科技有限公司 一种锂离子电池负极片用粘接剂乳液的制备方法
CN103828114A (zh) * 2011-09-26 2014-05-28 住友化学株式会社 二次电池用粘合树脂组合物
JP2014192136A (ja) * 2013-03-28 2014-10-06 Asahi Kasei Corp 非水電解質二次電池用正極の製造方法及び非水電解質二次電池
CN104170121A (zh) * 2012-03-28 2014-11-26 日本瑞翁株式会社 二次电池用多孔膜及其制造方法、二次电池用电极、二次电池用隔板及二次电池
CN108470909A (zh) * 2018-03-13 2018-08-31 陕西科技大学 一种交联网络复合粘接剂及其应用和基于其制备的锂离子电池负极材料和制备方法
CN111825804A (zh) * 2020-07-27 2020-10-27 日照广大建筑材料有限公司 一种锂离子二次电池负极用共聚物胶乳、制备方法及应用
KR20210045591A (ko) * 2019-10-17 2021-04-27 현대자동차주식회사 계면 특성이 향상된 전고체 전지용 전극 및 이의 제조방법
CN113045777A (zh) * 2021-03-15 2021-06-29 珠海冠宇电池股份有限公司 一种负极分散剂及含有该分散剂的锂离子电池
CN113410468A (zh) * 2021-08-19 2021-09-17 江苏卓高新材料科技有限公司 负极粘结剂及其制备方法、负极片的制备方法、锂离子电池
US20210320292A1 (en) * 2020-04-09 2021-10-14 Uchicago Argonne, Llc Electroactive materials for secondary batteries
CN113880999A (zh) * 2021-10-14 2022-01-04 惠州亿纬锂能股份有限公司 一种粘接剂及其制备方法和应用
CN114276461A (zh) * 2021-12-27 2022-04-05 重庆力宏精细化工有限公司 一种羧甲基纤维素钠及其制备方法和一种电池负极浆料及其制备方法
CN114520329A (zh) * 2020-11-19 2022-05-20 比亚迪股份有限公司 粘接剂及其制备方法和浆料

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3721727B2 (ja) * 1997-07-04 2005-11-30 Ｊｓｒ株式会社 電池電極用バインダー
KR102127876B1 (ko) * 2012-06-07 2020-06-29 제온 코포레이션 부극 슬러리 조성물, 리튬 이온 이차 전지 부극 및 리튬 이온 이차 전지
US9570751B2 (en) * 2013-02-26 2017-02-14 Samsung Sdi Co., Ltd. Binder composition for secondary battery, anode including the binder composition, and lithium battery including the anode
CN106663813B (zh) * 2014-09-05 2020-12-08 日本瑞翁株式会社 二次电池电极用粘结剂组合物、二次电池电极用浆料组合物、二次电池用电极和二次电池
WO2020045246A1 (ja) * 2018-08-29 2020-03-05 日本ゼオン株式会社 非水系二次電池接着層用組成物、非水系二次電池用電池部材およびその製造方法、並びに非水系二次電池用積層体の製造方法および非水系二次電池の製造方法
CN111463401B (zh) * 2020-03-28 2021-06-29 珠海冠宇电池股份有限公司 一种锂离子电池负极及其制备方法

Patent Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030113626A1 (en) * 1997-03-04 2003-06-19 Nippon Zeon Co., Ltd. Binder for battery, slurry for battery electrode, electrode for lithium secondary battery, and lithium secondary battery
CN103828114A (zh) * 2011-09-26 2014-05-28 住友化学株式会社 二次电池用粘合树脂组合物
CN104170121A (zh) * 2012-03-28 2014-11-26 日本瑞翁株式会社 二次电池用多孔膜及其制造方法、二次电池用电极、二次电池用隔板及二次电池
CN103173161A (zh) * 2013-03-08 2013-06-26 东莞新能源科技有限公司 一种锂离子电池负极片用粘接剂乳液的制备方法
JP2014192136A (ja) * 2013-03-28 2014-10-06 Asahi Kasei Corp 非水電解質二次電池用正極の製造方法及び非水電解質二次電池
CN108470909A (zh) * 2018-03-13 2018-08-31 陕西科技大学 一种交联网络复合粘接剂及其应用和基于其制备的锂离子电池负极材料和制备方法
KR20210045591A (ko) * 2019-10-17 2021-04-27 현대자동차주식회사 계면 특성이 향상된 전고체 전지용 전극 및 이의 제조방법
US20210320292A1 (en) * 2020-04-09 2021-10-14 Uchicago Argonne, Llc Electroactive materials for secondary batteries
CN111825804A (zh) * 2020-07-27 2020-10-27 日照广大建筑材料有限公司 一种锂离子二次电池负极用共聚物胶乳、制备方法及应用
CN114520329A (zh) * 2020-11-19 2022-05-20 比亚迪股份有限公司 粘接剂及其制备方法和浆料
CN113045777A (zh) * 2021-03-15 2021-06-29 珠海冠宇电池股份有限公司 一种负极分散剂及含有该分散剂的锂离子电池
CN113410468A (zh) * 2021-08-19 2021-09-17 江苏卓高新材料科技有限公司 负极粘结剂及其制备方法、负极片的制备方法、锂离子电池
CN113880999A (zh) * 2021-10-14 2022-01-04 惠州亿纬锂能股份有限公司 一种粘接剂及其制备方法和应用
CN114276461A (zh) * 2021-12-27 2022-04-05 重庆力宏精细化工有限公司 一种羧甲基纤维素钠及其制备方法和一种电池负极浆料及其制备方法

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
See also references of EP4450580A4 *
XIONG, PENG; WANG, XIAOBO; YANG, YANFEI; ZHU, XING; HU, ZHIHAI; FAN, MINGXIA; XIONG, JIAN; JINANG, GUODONG; YUAN, SONGDONG: "Preparation of Sodium Carboxymethyl Cellulose of Li-ion Battery Binder and its Application on Silicon Cathode", JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY, WUHAN LIGONG DAXUE, CN, no. 04, 30 April 2016 (2016-04-30), CN , pages 26 - 30, XP009551751, ISSN: 1671-4431 *
XU, ZHONGYUAN; WANG, JIN; XU, XUN; TANG, CHENMING: "Optimization of Slurry Stability for Lithium Ion Battery", CHINESE JOURNAL OF POWER SOURCES, JIXIE DIANZI GONGYEBU DIANYUAN QINGBAOWANG , TIANJIN, CN, no. 04, 20 April 2015 (2015-04-20), CN , pages 743 - 744, XP009551752, ISSN: 1002-087X *

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