WO2023087218A1 - 负极极片及其制备方法、二次电池、电池模块、电池包和用电装置 - Google Patents

负极极片及其制备方法、二次电池、电池模块、电池包和用电装置 Download PDF

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WO2023087218A1
WO2023087218A1 PCT/CN2021/131507 CN2021131507W WO2023087218A1 WO 2023087218 A1 WO2023087218 A1 WO 2023087218A1 CN 2021131507 W CN2021131507 W CN 2021131507W WO 2023087218 A1 WO2023087218 A1 WO 2023087218A1
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negative electrode
region
battery
electrode sheet
solid electrolyte
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English (en)
French (fr)
Inventor
王细辉
许文竹
葛销明
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Contemporary Amperex Technology Co Ltd
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Contemporary Amperex Technology Co Ltd
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Priority to CN202180094469.4A priority Critical patent/CN116941091A/zh
Priority to PCT/CN2021/131507 priority patent/WO2023087218A1/zh
Priority to EP21964276.6A priority patent/EP4235902A4/en
Priority to US18/198,844 priority patent/US12586792B2/en
Publication of WO2023087218A1 publication Critical patent/WO2023087218A1/zh
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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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0561—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of inorganic materials only
    • H01M10/0562—Solid materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0565—Polymeric materials, e.g. gel-type or solid-type
    • 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
    • H01M4/04—Processes of manufacture in general
    • H01M4/0402—Methods of deposition of the material
    • H01M4/0416—Methods of deposition of the material involving impregnation with a solution, dispersion, paste or dry powder
    • 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
    • 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
    • H01M4/134—Electrodes based on metals, Si or alloys
    • 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
    • H01M4/139—Processes of manufacture
    • H01M4/1393—Processes of manufacture of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • 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
    • H01M4/139—Processes of manufacture
    • H01M4/1395—Processes of manufacture of electrodes based on metals, Si or alloys
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/364—Composites as mixtures
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386—Silicon or alloys based on silicon
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/387—Tin or alloys based on tin
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • 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
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0065—Solid electrolytes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the technical field of lithium batteries, in particular to a negative pole piece, and also relates to a preparation method of the negative pole piece, a secondary battery, a battery module, a battery pack and an electrical device.
  • the purpose of the present application is to provide a negative electrode sheet, a method for preparing the negative electrode sheet, a secondary battery containing the negative electrode sheet, a battery module, a battery pack, and an electrical device, aiming at simultaneously improving the cycle performance and storage capacity of the battery. performance and security.
  • the first aspect of the present application provides a negative electrode sheet, including a negative electrode current collector and a negative electrode film layer, the negative electrode film layer is arranged on at least one surface of the negative electrode current collector; the negative electrode film layer includes a first A region and a second region, the first region does not contain a solid electrolyte and the second region contains a solid electrolyte.
  • the negative electrode sheet of the present application can still ensure the normal deintercalation of active ions in the presence of a small amount of electrolyte, which solves the problem of lithium deposition in the negative electrode caused by electrolyte extrusion, so that the battery has good cycle performance and storage performance and safety performance.
  • the first region includes a first film layer region and a second film layer region along the width direction of the negative electrode film layer, and the second region is located between the first film layer region and the second film layer region; the negative electrode film layer
  • the width of the first layer area is marked as L
  • the width of the first layer area is marked as L 1
  • the width of the second area is marked as L 2
  • the width of the second layer area is marked as L 3 .
  • the negative electrode sheet of this application sets the second area containing the solid electrolyte between the first film layer area and the second film layer area, which effectively solves the problem of lithium analysis caused by electrolyte extrusion, and significantly improves the cycle performance of the battery. , storage performance and security.
  • This setting can ensure that the second region containing the solid electrolyte is located in the middle of the negative electrode film layer, which solves the problem of lithium precipitation caused by electrolyte extrusion caused by the expansion of the middle of the pole piece, thereby improving the cycle performance, storage performance and safety of the battery at the same time .
  • Adopting the second region containing the solid electrolyte in this wide range can maintain the normal deintercalation of active ions even when the electrolyte is squeezed out, reducing the negative electrode lithium deposition, so that the negative electrode sheet of the present application has good cycle performance, Storage performance and security while maintaining high energy density.
  • the mass proportion of the solid electrolyte in the second region is greater than 0 and not greater than 30%, and may be 15%-30%. If the mass proportion of the solid electrolyte in the second region is too large, it is easy to cause the loss of the energy density of the pole piece.
  • the mass proportion is limited to be greater than 0 and not greater than 30%. It ensures the normal deintercalation of active ions, solves the problem of lithium deposition in the negative electrode caused by the large expansion force in the middle of the negative electrode, reduces the loss of electrode energy density, and ensures that the electrode has sufficient energy density.
  • L 1 L 3 . It facilitates the processing of the negative pole piece and improves the production efficiency of the negative pole piece.
  • the second area is located in the middle of the negative electrode film layer along the width direction, which can better solve the problem of negative electrode lithium precipitation caused by the large expansion force of the center of the pole piece. question.
  • the solid electrolyte is at least one selected from oxide solid electrolytes, sulfide solid electrolytes and polymer solid electrolytes. These solid electrolytes can all be used in the second region to simultaneously improve the cycle performance, storage performance, and safety of the battery.
  • both the first region and the second region contain negative electrode active materials.
  • the negative electrode active materials in the first region and the second region can be negative electrode active materials known in the art for batteries.
  • the negative electrode active materials in the first region and the second region are each independently selected from at least one of artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials and lithium titanate.
  • the silicon-based material may be selected from at least one of elemental silicon, silicon-oxygen compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys.
  • the tin-based material can be selected from at least one of simple tin, tin oxide and tin alloy.
  • the present application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials of batteries can also be used.
  • These negative electrode active materials may be used alone or in combination of two or more.
  • the negative active materials in the first region and the second region are independently graphite and/or silicon-based materials.
  • the porosity of the first region is ⁇ 24%; optionally 24%-28%.
  • the porosity of the second region is ⁇ 20%; optionally 20%-24%.
  • the first region does not contain a solid electrolyte, and the larger porosity on the pole piece is conducive to the transmission of lithium ions; at the same time, the second region contains a solid electrolyte, and the smaller porosity is conducive to improving the contact between the solid electrolyte and the active material and ensuring lithium ions Transmission; this application is aimed at using the electrolyte as a lithium ion transport conductor system.
  • the above-mentioned porosity not only ensures that the active ions have sufficient diffusion channels in the negative electrode sheet, but also meets the requirement that the electrode sheet does not decompose lithium, and at the same time enables the electrode sheet to have sufficient diffusion channels. Fully infiltrated to ensure the kinetics of the anode material, so as to ensure that the battery has good cycle performance, storage performance and safety.
  • the second aspect of the present application provides a method for preparing the negative electrode sheet of the first aspect of the present application, comprising the following steps:
  • first negative electrode slurry and a second negative electrode slurry, wherein the first negative electrode slurry does not contain a solid electrolyte, and the second negative electrode slurry contains a solid electrolyte;
  • the first negative electrode slurry is coated on the first section, and the second negative electrode slurry is coated on the second section.
  • the prepared negative electrode sheet can still ensure the normal deintercalation of active ions in the presence of a small amount of electrolyte, which alleviates the problem of lithium deposition in the negative electrode caused by electrolyte extrusion, so that the battery has good cycle performance, storage performance and safety performance.
  • the first section is divided into a first section and a second section along the width direction of the negative electrode collector, and the second section is located between the first section and the second section.
  • the second negative electrode slurry containing solid electrolyte is coated on the second section between the first part and the second part to prepare the negative electrode sheet, which effectively alleviates the problem of lithium precipitation caused by the electrolyte extrusion in the middle of the electrode sheet , significantly improving the cycle performance, storage performance and safety of the battery.
  • the ratio of the width of the first portion to the negative electrode current collector is greater than 0 and not greater than 0.75, and may be 0.3-0.55.
  • the ratio of the width of the second portion to the negative electrode current collector is greater than 0 and not greater than 0.75, and may be 0.25-0.75.
  • the ratio of the width of the second section to the negative electrode collector is greater than 0 and not greater than 0.75, and may be 0.3-0.55.
  • the second section of this width range is used to coat the second slurry containing solid electrolyte, even when the electrolyte is squeezed out, it can still maintain the normal deintercalation of active ions, reduce the lithium deposition of the negative electrode, and make the negative electrode of this application
  • the pole piece has good cycle performance, storage performance and safety, while maintaining a high energy density.
  • the width of the first portion and the second portion are equal. This setting is convenient for the preparation and processing of the negative pole piece, and improves the production efficiency of the negative pole piece. Lida caused by negative electrode lithium analysis problem.
  • the mass content of the solid electrolyte in the second negative electrode slurry is greater than 0 and not greater than 30%, and may be 15%-30%. If the mass ratio of the solid electrolyte in the second negative electrode slurry is too large, it will easily lead to the loss of the energy density of the negative electrode sheet. Maintain the normal deintercalation of lithium ions under the condition of out, solve the problem of lithium deposition at the negative electrode, reduce the loss of electrode energy density, and ensure that the pole piece has sufficient energy density.
  • the negative electrode sheet of the first aspect of the present application is prepared by the method of the second aspect of the present application.
  • the position of the first segment on the negative electrode current collector corresponds to the position of the first region on the negative electrode film layer
  • the position of the second segment on the negative electrode current collector corresponds to the position of the second region on the negative electrode film layer.
  • the third aspect of the present application provides a secondary battery, comprising the negative electrode sheet of the first aspect of the present application or the negative electrode sheet prepared according to the method of the second aspect of the present application.
  • a fourth aspect of the present application provides a battery module including the secondary battery of the third aspect of the present application.
  • a fifth aspect of the present application provides a battery pack, including the battery module of the fourth aspect of the present application.
  • the sixth aspect of the present application provides an electric device, including at least one selected from the secondary battery of the third aspect of the present application, the battery module of the fourth aspect of the present application, and the battery pack of the fifth aspect of the present application kind.
  • the negative pole piece of this application can still ensure the normal deintercalation of active ions in the presence of a small amount of electrolyte, which solves the problem of lithium deposition in the negative electrode caused by electrolyte extrusion; the negative pole piece of this application improves the cycle performance and storage performance of the battery at the same time and safety performance; the negative electrode sheet of the present application has a higher energy density.
  • FIG. 1 is a schematic diagram of a secondary battery according to an embodiment of the present application.
  • FIG. 2 is an exploded view of the secondary battery according to one embodiment of the present application shown in FIG. 1 .
  • FIG. 3 is a schematic diagram of a battery module according to an embodiment of the present application.
  • FIG. 4 is a schematic diagram of a battery pack according to an embodiment of the present application.
  • FIG. 5 is an exploded view of the battery pack according to one embodiment of the present application shown in FIG. 4 .
  • FIG. 6 is a schematic diagram of an electrical device in which a secondary battery is used as a power source according to an embodiment of the present application.
  • FIG. 7 is a schematic structural view of the negative electrode sheet in Examples 1-15 of the present application.
  • ranges disclosed herein are defined in terms of lower and upper limits, and 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 and may be combined arbitrarily, ie 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, it is understood that ranges of 60-110 and 80-120 are contemplated. Additionally, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, 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" indicates that all real numbers between "0-5" have been listed in this article, and "0-5" is only an abbreviated representation of the combination of these values.
  • 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 in sequence, and may also include steps (b) and (a) performed in sequence.
  • step (c) means that step (c) may be added to the method in any order, for example, 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) and so on.
  • the “comprising” and “comprising” mentioned in this application mean open or closed.
  • the “comprising” and “comprising” may mean that other components not listed may be included or included, or only listed components may be included or included.
  • the term "or” is inclusive unless otherwise stated.
  • the phrase "A or B” means “A, B, or both A and B.” More specifically, the condition "A or B” is satisfied by either of the following: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists) ; or both A and B are true (or exist).
  • Secondary batteries also known as rechargeable batteries or accumulators, refer to batteries that can be activated by charging the active materials and continue to be used after the battery is discharged.
  • a secondary battery typically includes a positive pole piece, a negative pole piece, a separator, and an electrolyte.
  • active ions such as lithium ions
  • the separator is arranged between the positive pole piece and the negative pole piece, which mainly plays a role in preventing the short circuit of the positive and negative poles, and at the same time allows active ions to pass through.
  • the electrolyte is between the positive pole piece and the negative pole piece, and mainly plays the role of conducting active ions.
  • the negative electrode sheet generally includes a negative electrode current collector and a negative electrode film layer arranged on at least one surface of the negative electrode current collector, and the negative electrode film layer includes a negative electrode active material.
  • the negative electrode current collector has two opposing surfaces in its own thickness direction, and the negative electrode film layer is disposed on any one or both of the two opposing surfaces of the negative electrode current collector.
  • the negative electrode sheet will expand and shrink, resulting in uneven stress distribution inside the battery; especially, the expansion of the negative electrode sheet during the charging process will cause the electrolyte to be squeezed out, and the negative electrode sheet will shrink during the discharge process.
  • the electrolyte is too late to replenish, resulting in the "electrolyte extrusion" effect, which affects the normal deintercalation of active ions, resulting in lithium deposition at the negative electrode, which affects the cycle performance and safety performance of the battery.
  • one embodiment of the present application provides a negative electrode sheet, including a negative electrode current collector and a negative electrode film layer, the negative electrode film layer is arranged on at least one surface of the negative electrode current collector; the negative electrode film layer includes a first region along the width direction and a second region, the first region not containing a solid electrolyte and the second region containing a solid electrolyte.
  • the existing technology mainly improves the "electrolyte extrusion" effect by reducing the expansion force of the pole piece to solve the problem of lithium deposition at the negative electrode, but the improvement effect of this method is limited; and, with the market demand for the energy density of the battery cell Silicon material is used as the mainstream negative electrode active material, but silicon material is easier to expand, and it is difficult to solve the problem of lithium precipitation by reducing the expansion force.
  • the negative electrode sheet of the present application contains a solid electrolyte in the second region. Even if the electrolyte is squeezed out, the normal deintercalation of active ions can still be guaranteed in the presence of a small amount of electrolyte, which fundamentally solves the problem of electrolyte extrusion.
  • the problem of lithium precipitation at the negative electrode caused by the problem slows down the decay rate of the battery capacity, so that the battery has good cycle performance, storage performance and safety performance at the same time.
  • the first region includes a first film layer region and a second film layer region along the width direction of the negative electrode film layer, and the second region is located between the first film layer region and the second film layer region; the negative electrode film layer
  • the width of the first layer area is marked as L
  • the width of the first layer area is marked as L 1
  • the width of the second area is marked as L 2
  • the width of the second layer area is marked as L 3 .
  • the negative pole piece of this application arranges the second region containing the solid electrolyte between the first film layer area and the second film layer area, which effectively alleviates the problem of lithium analysis caused by electrolyte extrusion caused by the expansion of the middle part of the pole piece, and significantly improves It improves the cycle performance, storage performance and safety of the battery.
  • 0 ⁇ L 1 /L 0 ⁇ L 1 /L ⁇ 0.75; alternatively, 0.3 ⁇ L 1 /L ⁇ 0.55, such as 0.1, 0.125, 0.2, 0.3, 0.375, 0.4, 0.45, 0.5, 0.55, 0.6.
  • Adopting the second region containing the solid electrolyte in this wide range can maintain the normal deintercalation of active ions even when the electrolyte is squeezed out, reducing the negative electrode lithium deposition, so that the negative electrode sheet of the present application has good cycle performance, Storage performance and security while maintaining high energy density.
  • the mass proportion of the solid electrolyte in the second region is greater than 0 and not greater than 30%, optionally 15%-30%, such as 2%, 5%, 8%, 10%, 15%, 20%, 25%. If the mass proportion of the solid electrolyte in the second region is too large, it is easy to cause the loss of the energy density of the pole piece.
  • the mass proportion is limited to be greater than 0 and not greater than 30%. It ensures the normal deintercalation of active ions, solves the problem of lithium deposition in the negative electrode caused by the large expansion force in the middle of the negative electrode, reduces the loss of electrode energy density, and ensures that the electrode has sufficient energy density.
  • L 1 L 3 .
  • This setting facilitates the processing of the negative pole piece and improves the production efficiency of the negative pole piece.
  • the second area is located in the middle of the negative electrode film layer along the width direction, which can better solve the problem caused by the large expansion force of the negative pole piece center. Negative electrode lithium analysis problem.
  • the thickness of the first region and the second region are equal. Such setting can ensure the uniformity of the thickness of the negative electrode film layer, which is beneficial to the normal use of the negative electrode sheet, and at the same time facilitates the processing and production of the negative electrode sheet.
  • the thickness of the first region and the second region is the conventional thickness of the negative electrode film layer in the field, for example, the thickness of the first region and the second region is 100-250 ⁇ m. This can not only ensure the normal use of the negative electrode sheet, but also ensure the normal deintercalation of active ions through the second region containing the solid electrolyte, and solve the problem of lithium deposition in the negative electrode caused by excessive expansion force in the middle of the negative electrode.
  • the solid electrolyte is at least one selected from oxide solid electrolytes, sulfide solid electrolytes, and polymer solid electrolytes.
  • the oxide solid electrolyte may include at least one of the following: LLZTO solid electrolyte, perovskite Li 3.3 La 0.56 TiO 3 , sodium fast ion conductor LiTi 2 (PO 4 ) 3 , lithium fast ion conductor Li 14 Zn(GeO 4 ) 4 , garnet-type Li 7 La 3 Zr 2 O 12 ;
  • sulfide solid electrolyte may include at least one of the following: Li 3 PS 4 , Li 6 PS 5 Cl, Li 10 GeP 2 S 12 , Li 7 P 3 S 11 ;
  • Polymer solid electrolyte may include at least one of the following: polyoxyethylene PEO, polyvinylidene fluoride PVDF, polyacrylonitrile PAN, polymethyl methacrylate PMMA, polyvinylpyrrolidone PVP or polyvin
  • the mass proportion of the negative electrode active material in the first region adopts the mass proportion of the negative electrode active material in the negative electrode film layer known in the art.
  • the mass proportion of the negative electrode active material in the second region is 60%-95%, such as 65%, 68%, 70.5%, 75.5%, 80.5%, 85.5%, 90.5%, 92%.
  • both the first region and the second region contain a negative active material.
  • the negative electrode active materials in the first region and the second region can be negative electrode active materials known in the art for batteries.
  • the negative electrode active materials in the first region and the second region are each independently selected from at least one of artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials and lithium titanate.
  • the silicon-based material may be selected from at least one of elemental silicon, silicon-oxygen compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys.
  • the tin-based material can be selected from at least one of simple tin, tin oxide and tin alloy.
  • the present application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials of batteries can also be used. These negative electrode active materials may be used alone or in combination of two or more.
  • the mass proportion of the silicon-based material in the second region is 1%-8%, such as 1.2%, 2.3%, 3.5%, 4.5%, 5.5%.
  • the second region also contains a silicon-based material with a relatively high energy density, so as to maintain the high energy density of the negative electrode sheet.
  • the porosity of the first region is ⁇ 24%; optionally 24%-28%.
  • the porosity of the second region is ⁇ 20%; optionally 20%-24%.
  • the first region does not contain a solid electrolyte, and the larger porosity on the pole piece is conducive to the transmission of lithium ions; at the same time, the second region contains a solid electrolyte, and the smaller porosity is conducive to improving the contact between the solid electrolyte and the active material and ensuring lithium ions Transmission; this application is aimed at using the electrolyte as a lithium ion transport conductor system.
  • the above-mentioned porosity not only ensures that the active ions have sufficient diffusion channels in the negative electrode sheet, but also meets the requirement that the electrode sheet does not decompose lithium, and at the same time enables the electrode sheet to have sufficient diffusion channels. Fully infiltrated to ensure the kinetics of the anode material, so as to ensure that the battery has good cycle performance, storage performance and safety.
  • a metal foil or a composite current collector can be used as the negative electrode current collector.
  • copper foil can be used as the metal foil.
  • the composite current collector may include a base layer of polymer material and a metal layer formed on at least one surface of the base material of polymer material.
  • Composite current collectors can be formed by metal materials (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on polymer material substrates (such as polypropylene (PP), polyethylene terephthalic acid It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • the first region and the second region optionally further include an adhesive.
  • the binder can be selected from styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethyl At least one of acrylic acid (PMAA) and carboxymethyl chitosan (CMCS).
  • the mass proportion of the binder in the first region and the second region is the mass proportion of the binder in the negative electrode film layer generally used in this field.
  • the first region and the second region optionally further include a conductive agent.
  • the conductive agent can be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • the mass proportion of the conductive agent in the first region and the second region is the mass proportion of the conductive agent in the negative electrode film layer generally used in the art.
  • the first region and the second region may optionally include other additives, such as thickeners [such as carboxymethylcellulose sodium (CMC-Na)] and the like.
  • thickeners such as carboxymethylcellulose sodium (CMC-Na)
  • the present application also proposes a method for preparing a negative electrode sheet, comprising the following steps:
  • first negative electrode slurry and a second negative electrode slurry, wherein the first negative electrode slurry does not contain a solid electrolyte, and the second negative electrode slurry contains a solid electrolyte;
  • the first negative electrode slurry is coated on the first section, and the second negative electrode slurry is coated on the second section.
  • the prepared negative electrode sheet can still ensure the normal deintercalation of active ions in the presence of a small amount of electrolyte, which alleviates the problem of lithium deposition in the negative electrode caused by electrolyte extrusion, so that the battery has good cycle performance, Storage performance and security performance.
  • the first section is divided into a first section and a second section along the width direction of the negative electrode current collector, and the second section is located between the first section and the second section.
  • the second negative electrode slurry containing solid electrolyte is coated on the second section between the first part and the second part to prepare the negative electrode sheet, which effectively alleviates the problem of lithium precipitation caused by the electrolyte extrusion in the middle of the electrode sheet , significantly improving the cycle performance, storage performance and safety of the battery.
  • the ratio of the width of the first part to the negative current collector is greater than 0 and not greater than 0.75, and may be 0.3-0.55, such as 0.1, 0.125, 0.2, 0.3, 0.375, 0.4, 0.45, 0.5, 0.55, 0.6.
  • the ratio of the second part to the width of the negative electrode current collector is greater than 0 and not greater than 0.75, optionally 0.25-0.75, such as 0.1, 0.125, 0.2, 0.3, 0.375, 0.4, 0.45, 0.5, 0.55 , 0.6, 0.7.
  • the ratio of the width of the second section to the negative current collector is greater than 0 and not greater than 0.75, optionally 0.3-0.55, such as 0.1, 0.15, 0.2, 0.25, 0.3, 0.4, 0.5, 0.6, 0.7, 0.75.
  • the second section of this width range is used to coat the second slurry containing solid electrolyte, even when the electrolyte is squeezed out, it can still maintain the normal deintercalation of active ions, reduce the lithium deposition of the negative electrode, and make the negative electrode of this application
  • the pole piece has good cycle performance, storage performance and safety, while maintaining a high energy density.
  • the width of the first portion and the second portion are equal. This setting is convenient for the preparation and processing of the negative pole piece, and improves the production efficiency of the negative pole piece. Lida caused by negative electrode lithium analysis problem.
  • the mass content of the solid electrolyte in the second negative electrode slurry is greater than 0 and not greater than 30%, optionally 15%-30%, such as 2%, 5%, 8%, 10%, 15% , 20%, 25%. If the mass ratio of the solid electrolyte in the second negative electrode slurry is too large, it will easily lead to the loss of the energy density of the negative electrode sheet. Maintain the normal deintercalation of lithium ions under the condition of out, solve the problem of lithium deposition at the negative electrode, reduce the loss of electrode energy density, and ensure that the pole piece has sufficient energy density.
  • the above-mentioned negative electrode sheet is prepared by this method.
  • the position of the first segment on the negative electrode current collector corresponds to the position of the first region on the negative electrode film layer
  • the position of the second segment on the negative electrode current collector corresponds to the position of the second region on the negative electrode film layer.
  • the coating surface density of the first negative electrode slurry on the first section is 5-20 mg/m 2 , for example, 12 mg/m 2 .
  • the coating areal density of the second negative electrode slurry on the second section is 8-25 mg/m 2 , for example, 16 mg/m 2 .
  • the uniformity and consistency of the overall thickness of the negative electrode film layer can be guaranteed, which is beneficial to the normal use of the negative electrode sheet and facilitates the preparation of the negative electrode sheet.
  • the first negative electrode slurry is formed by dispersing the negative active material, optional conductive agent, optional binder, and any other components in a solvent.
  • the second negative electrode slurry is formed by dispersing the solid electrolyte, negative active material, optional conductive agent, optional binder, and any other components in a solvent.
  • the negative electrode active materials in the first negative electrode slurry and the second negative electrode slurry can be negative electrode active materials known in the art for batteries.
  • the negative electrode active materials in the first region and the second region are each independently selected from at least one of artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials and lithium titanate.
  • the silicon-based material may be selected from at least one of elemental silicon, silicon-oxygen compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys.
  • the tin-based material can be selected from at least one of simple tin, tin oxide and tin alloy.
  • the present application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials of batteries can also be used. These negative electrode active materials may be used alone or in combination of two or more.
  • the mass proportion of the silicon-based material in the second slurry is 1%-8%, such as 1.2%, 2.3%, 3.5%, 4.5%, 5.5%. This can maintain a high energy density of the negative electrode sheet.
  • the solid content of the first negative electrode slurry and the second negative electrode slurry is suitable for normal coating to prepare pole pieces.
  • the positive electrode sheet generally includes a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode collector.
  • the positive electrode film layer includes the positive electrode active material according to the first aspect of the present application.
  • the positive electrode current collector has two opposing surfaces in its own thickness direction, and the positive electrode film layer is disposed on any one or both of the two opposing surfaces of the positive electrode current collector.
  • a metal foil or a composite current collector can be used as the positive electrode current collector.
  • aluminum foil can be used as the metal foil.
  • the composite current collector may include a polymer material base and a metal layer formed on at least one surface of the polymer material base.
  • the composite current collector can be formed by forming metal materials (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyethylene terephthalic acid It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PET polyethylene glycol ester
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the positive electrode active material may be a positive electrode active material known in the art for batteries.
  • the positive active material may include at least one of the following materials: olivine-structured lithium-containing phosphate, lithium transition metal oxide, and their respective modified compounds.
  • the present application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials of batteries can also be used. These positive electrode active materials may be used alone or in combination of two or more.
  • 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 (also abbreviated as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O 2 (also abbreviated as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (also abbreviated as 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 LiNi
  • the olivine structure contains Examples of lithium phosphates may include, but are not limited to, lithium iron phosphate (such as LiFePO 4 (also may be abbreviated as LFP)), composite materials of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), lithium manganese phosphate and carbon At least one of a composite material, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon.
  • lithium iron phosphate such as LiFePO 4 (also may be abbreviated as LFP)
  • composite materials of lithium iron phosphate and carbon such as LiMnPO 4
  • LiMnPO 4 lithium manganese phosphate and carbon
  • the positive electrode film layer may further optionally include a binder.
  • the binder may include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene At least one of meta-copolymer, tetrafluoroethylene-hexafluoropropylene copolymer and fluorine-containing acrylate resin.
  • the positive electrode film layer may also optionally include a conductive agent.
  • 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 used to prepare the positive electrode sheet, such as positive electrode active material, conductive agent, binder and any other components, are dispersed in a solvent (such as N -methylpyrrolidone) 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 sheet can be obtained.
  • a solvent such as N -methylpyrrolidone
  • electrolyte plays the role of conducting ions between the positive pole piece and the negative pole piece.
  • the application does not have specific restrictions on the type of electrolyte, which can be selected according to requirements.
  • electrolytes can be liquid, gel or all solid.
  • the electrolyte is liquid and includes an electrolyte salt and a solvent.
  • the electrolyte salt may be selected from lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, trifluoromethane At least one of lithium sulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium difluorooxalate borate, lithium difluorodifluorooxalatephosphate and lithium tetrafluorooxalatephosphate.
  • the solvent may be selected from ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, Butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate At least one of ester, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.
  • the electrolyte also optionally includes additives.
  • the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain performances of the battery, such as additives that improve battery overcharge performance, additives that improve high-temperature or low-temperature performance of the battery, and the like.
  • a separator is further included in the secondary battery.
  • the present application has no particular limitation on the type of the isolation membrane, and any known porous structure isolation membrane with good chemical stability and mechanical stability can be selected.
  • the material of the isolation film can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.
  • the separator can be a single-layer film or a multi-layer composite film, without any particular limitation. When the separator is a multilayer composite film, the materials of each layer may be the same or different, and there is no particular limitation.
  • the positive pole piece, the negative pole piece and the separator can be made into an electrode assembly through a winding process or a lamination process.
  • the secondary battery may include an outer package.
  • the outer package can be used to package the above-mentioned electrode assembly and electrolyte.
  • the outer package of the secondary battery can be a hard case, such as a hard plastic case, an aluminum case, a steel case, and the like.
  • the outer packaging of the secondary battery may also be a soft bag, such as a bag-type soft bag.
  • the material of the soft case may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, polybutylene succinate, and the like.
  • FIG. 1 shows a square-shaped secondary battery 5 as an example.
  • the outer package may include a housing 51 and a cover 53 .
  • the housing 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plates enclose to form an accommodating cavity.
  • the housing 51 has an opening communicating with the accommodating cavity, and the cover plate 53 can cover the opening to close the accommodating cavity.
  • the positive pole piece, the negative pole piece and the separator can be formed into an electrode assembly 52 through a winding process or a lamination process.
  • the electrode assembly 52 is packaged in the containing chamber. Electrolyte is infiltrated in the electrode assembly 52 .
  • the number of electrode assemblies 52 contained in the secondary battery 5 can be one or more, and those skilled in the art can select according to specific actual needs.
  • the secondary battery can be assembled into a battery module, and the number of secondary batteries contained in the battery module can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery module.
  • FIG. 3 is a battery module 4 as an example.
  • a plurality of secondary batteries 5 may be arranged in sequence along the length direction of the battery module 4 .
  • the plurality of secondary batteries 5 may be fixed by fasteners.
  • the battery module 4 may also include a case having a housing space in which a plurality of secondary batteries 5 are accommodated.
  • the above-mentioned battery modules can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery pack.
  • the battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box.
  • the battery box includes an upper box body 2 and a lower box body 3 , the upper box body 2 can cover the lower box body 3 and form a closed space for accommodating the battery module 4 .
  • a plurality of battery modules 4 can be arranged in the battery box in any manner.
  • the present application also provides an electric device, which includes at least one of the secondary battery, battery module, or battery pack provided in the present application.
  • a secondary battery, a battery module, or a battery pack can be used as a power source of a power consumption device, and can also be used as an energy storage unit of the power consumption device.
  • Electric devices can include mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but not limited thereto.
  • secondary batteries, battery modules, or battery packs can be selected according to their usage requirements.
  • FIG. 6 is an example of an electrical device.
  • the electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.
  • a battery pack or a battery module may be used.
  • Preparation of positive electrode sheet Dissolve positive active material ternary NCM811, binder polyvinylidene fluoride (PVDF), conductive agent acetylene black, and conductive agent carbon nanotubes in N at a mass ratio of 95.5:2:2:0.5. - Stir fully and evenly in methylpyrrolidone (NMP) to obtain a positive electrode slurry; uniformly coat the positive electrode slurry on an aluminum foil of a positive electrode current collector, dry, cold press, and cut to obtain a positive electrode sheet.
  • NMP methylpyrrolidone
  • Negative electrode active material graphite, silicon oxide, solid electrolyte LLZTO, conductive agent acetylene black, binder styrene-butadiene rubber (SBR), thickener sodium carboxymethyl cellulose (CMC- Na) was dissolved in deionized water according to the mass ratio of 89.3:1.2:5:2:1.5:1, fully stirred evenly, and negative electrode slurry 3 was obtained;
  • Negative electrode active material graphite, silicon oxide, solid electrolyte LLZTO, conductive agent acetylene black, binder styrene-butadiene rubber (SBR), thickener sodium carboxymethyl cellulose (CMC- Na) was dissolved in deionized water according to the mass ratio of 83.2:2.3:10:2:1.5:1, fully stirred evenly, and negative electrode slurry 4 was obtained;
  • negative electrode slurry 5 the negative electrode active material graphite, silicon oxide, solid electrolyte LLZTO, conductive agent acetylene black, binder styrene-butadiene rubber (SBR) and thickener sodium carboxymethyl cellulose (CMC- Na) was dissolved in deionized water according to the mass ratio of 77:3.5:15:2:1.5:1, fully stirred evenly, and negative electrode slurry 5 was obtained;
  • Negative electrode active material graphite, silicon oxide, solid electrolyte LLZTO, conductive agent acetylene black, binder styrene-butadiene rubber (SBR), thickener sodium carboxymethyl cellulose (CMC- Na) was dissolved in deionized water according to the mass ratio of 71:4.5:20:2:1.5:1, and fully stirred evenly to obtain negative electrode slurry 6;
  • Negative electrode active material graphite, silicon oxide, solid electrolyte LLZTO, conductive agent acetylene black, binder styrene-butadiene rubber (SBR) and thickener sodium carboxymethyl cellulose (CMC- Na) was dissolved in deionized water according to the mass ratio of 65:5.5:25:2:1.5:1, and fully stirred evenly to obtain negative electrode slurry 7;
  • the negative film layer of the negative pole sheet is divided into three parts accordingly, the width of the first film layer area is L1, the width of the second area is L2, the width of the second film layer area is L3, the total of the negative film layer The width is L, and the thicknesses of the first film region, the second region and the second film region are all 160 ⁇ m (after cold pressing).
  • Isolation film Polypropylene film is used.
  • the negative pole pieces of Examples 1 to 15 and Comparative Examples 1-3 were used respectively, and the positive pole piece made above was used, and a polyethylene film with a thickness of 16 ⁇ m was used as the separator, and the negative pole piece, the separator, and the positive pole piece were separated. Winding and lug welding, assembled into a hard-shell battery, through liquid injection (using the prepared electrolyte), and charging for the first time to make a spare hard-shell battery 1-15, A-C, the capacity of the battery cell is 7000mAh.
  • Embodiment 8 and Examples 11-15 of the present application show that: when the second region is located in the middle of the width direction of the negative electrode sheet, the number of cycles of the battery is the largest, the battery does not decompose lithium, and the overall performance is the best; when the first film layer When pure graphite is used as the active material in the region and the second film layer region, the cycle and storage performance of the battery is further improved, and lithium precipitation does not occur in the battery.
  • the negative electrode sheet of the present application can significantly improve the cycle performance and storage performance of the battery.
  • the optional solid electrolyte content of the negative pole piece is not less than 15%, and the width of the second region L 2 ⁇ 1/4L, so that the battery does not undergo lithium precipitation.
  • the present application is not limited to the above-mentioned embodiments.
  • the above-mentioned embodiments are merely examples, and within the scope of the technical solutions of the present application, embodiments that have substantially the same configuration as the technical idea and exert the same effects are included in the technical scope of the present application.
  • various modifications conceivable by those skilled in the art are added to the embodiments, and other forms constructed by combining some components in the embodiments are also included in the scope of the present application. .

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Abstract

本申请提供了一种负极极片、制备负极极片的方法、二次电池、电池模块、电池包和用电装置，其中，一种负极极片包括负极集流体和负极膜层，负极膜层设置在负极集流体的至少一个表面上；负极膜层沿宽度方向包括第一区域和第二区域，第一区域不包含固态电解质，第二区域包含固态电解质。本申请负极极片解决了电解液挤出造成的负极析锂问题，以保证活性离子的正常脱嵌，从而同时提高了电池的循环性能、存储性能和安全性。

Description

负极极片及其制备方法、二次电池、电池模块、电池包和用电装置 技术领域
本申请涉及锂电池技术领域，尤其涉及一种负极极片，还涉及该负极极片的制备方法、二次电池、电池模块、电池包和用电装置。
背景技术
近年来，随着二次电池广泛应用于水力、火力、风力和太阳能电站等储能电源系统，以及应用于电动工具、电动自行车、电动摩托车、电动汽车、军事装备、航空航天等多个领域。
如何使二次电池同时兼顾较好的循环性能和安全性能仍是亟待解决的重要问题。
发明内容
本申请的目的在于提供一种负极极片、制备该负极极片的方法、含有该负极极片的二次电池、电池模块、电池包和用电装置，旨在同时提高电池的循环性能、存储性能和安全性。
为了达到上述目的，本申请的第一方面提供一种负极极片，包括负极集流体和负极膜层，负极膜层设置在负极集流体的至少一个表面上；负极膜层沿宽度方向包括第一区域和第二区域，第一区域不包含固态电解质，第二区域包含固态电解质。
本申请的负极极片在少量电解液存在的情况下仍可以保证活性离子的正常脱嵌，解决了电解液挤出所造成的负极析锂问题，从而使电池兼具良好的循环性能、存储性能和安全性能。
在任意实施方式中，第一区域沿负极膜层的宽度方向包括第一膜 层区和第二膜层区，第二区域位于第一膜层区和第二膜层区之间；负极膜层的宽度记为L，第一膜层区的宽度记为L 1，第二区域的宽度记为L 2，第二膜层区的宽度记为L 3。本申请负极极片将含有固态电解质的第二区域设置在第一膜层区和第二膜层区之间，有效解决了电解液挤出带来的析锂问题，明显提高了电池的循环性能、存储性能和安全性。
在任意实施方式中，0<L 1/L≤0.75；可选地，0.3≤L 1/L≤0.55。
在任意实施方式中，0<L 3/L≤0.75；可选地，0.25≤L 3/L≤0.75。
这样设置可以保证含有固态电解质的第二区域位于负极膜层的中间位置，解决了极片中部膨胀导致电解液挤出所引发的析锂问题，从而同时改善电池的循环性能、存储性能和安全性。
在任意实施方式中，0<L 2/L≤0.75；可选地，0.3≤L 2/L≤0.55。采用该宽度范围的含有固态电解质的第二区域，即便在电解液挤出的情况下仍能保持活性离子的正常脱嵌，降低负极析锂，使得本申请负极极片兼具良好的循环性能、存储性能和安全性，同时保持较高的能量密度。
在任意实施方式中，固态电解质在第二区域中的质量占比大于0且不大于30％，可选为15％-30％。固态电解质在第二区域中的质量占比过大，容易造成极片能量密度的损失，限定质量占比大于0且不大于30％，既可以通过含有固态电解质的第二区域在电解液挤出的情况下保证活性离子的正常脱嵌，解决负极中部膨胀力大所造成的负极析锂问题，又降低了电极能量密度的损失，保证极片具有足够的能量密度。
在任意实施方式中，L 1＝L 3。方便了负极极片的加工，提高了负极极片的生产效率，同时使第二区域于负极膜层沿宽度方向的中间，能更好地解决因极片中心膨胀力大所引起的负极析锂问题。
在任意实施方式中，L 1＝L 2＝L 3。进一步方便极片的加工，提高生产效率。
在任意实施方式中，固态电解质为选自氧化物固态电解质、硫化 物固态电解质和聚合物固态电解质中的至少一种。这些固态电解质均可用于第二区域，以同时改善电池的循环性能、存储性能和安全性。
在任意实施方式中，第一区域和第二区域均包含负极活性材料。第一区域和第二区域中的负极活性材料可采用本领域公知的用于电池的负极活性材料。可选地，第一区域和第二区域中的负极活性材料各自独立地选自人造石墨、天然石墨、软炭、硬炭、硅基材料、锡基材料和钛酸锂中的至少一种。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。例如，第一区域和第二区域中的负极活性材料独立地为石墨和/或硅基材料。
在任意实施方式中，第一区域的孔隙率≥24％；可选为24％-28％。
在任意实施方式中，第二区域的孔隙率≥20％；可选为20％-24％。
第一区域不包含固态电解质，极片上较大的孔隙率有利于锂离子的传输；同时，第二区域包含固态电解质，较小的孔隙率有利于提高固态电解质和活性材料的接触并保证锂离子传输；本申请针对使用电解液作为锂离子传输导体的体系，上述孔隙率既保证活性离子在负极极片中具有足够的扩散通道，又能满足极片不析锂的需求，同时能使极片得到充分浸润，以保证阳极材料的动力学，从而保证电池兼具较好的循环性能、存储性能和安全性。
本申请的第二方面提供了一种制备本申请第一方面的负极极片的方法，包括如下步骤：
将负极集流体的至少一个表面沿宽度方向分成第一区段和第二区段；
提供第一负极浆料和第二负极浆料，其中，第一负极浆料不包含固态电解质，第二负极浆料包含固态电解质；
将第一负极浆料涂布在第一区段，将第二负极浆料涂布在第二区 段。
制备的负极极片在少量电解液存在的情况下仍可以保证活性离子的正常脱嵌，缓解了电解液挤出所造成的负极析锂问题，从而使电池兼具良好的循环性能、存储性能和安全性能。
在任意实施方式中，将第一区段沿负极集流体的宽度方向分成第一部分和第二部分，第二区段位于第一部分和第二部分之间。这样，在第一部分和第二部分之间的第二区段上涂布含固态电解质的第二负极浆料以制备负极极片，有效缓解了极片中部的电解液挤出导致的析锂问题，明显提高了电池的循环性能、存储性能和安全性。
在任意实施方式中，第一部分与负极集流体的宽度之比为大于0且不大于0.75，可选为0.3-0.55。
在任意实施方式中，第二部分与负极集流体的宽度之比为大于0且不大于0.75，可选为0.25-0.75。
这样保证了用于涂布第二浆料的第二区段位于极片中间位置，解决了极片中部的电解液挤出所造成的析锂问题，从而改善了电池的循环性能、存储性能和安全性。
在任意实施方式中，第二区段与负极集流体的宽度之比为大于0且不大于0.75，可选为0.3-0.55。采用该宽度范围的第二区段用于涂布含固态电解质的第二浆料，即便在电解液挤出的情况下仍能保持活性离子的正常脱嵌，降低负极析锂，使得本申请负极极片兼具良好的循环性能、存储性能和安全性，同时保持较高的能量密度。
在任意实施方式中，第一部分和第二部分的宽度相等。这一设置便于负极极片的制备和加工，提高了负极极片的生产效率，同时，这一设置能保证第二区段位于负极极片的中间，能更好地解决因负极极片中心膨胀力大所引起的负极析锂问题。
在任意实施方式中，第二负极浆料中固态电解质的质量含量为大于0且不大于30％，可选为15％-30％。固态电解质在第二负极浆料中的质量占比过大，容易导致负极极片的能量密度损失，限定质量占比大于0且不超过30％，既可以保证本申请负极极片在电解液挤出的 情况下维持锂离子的正常脱嵌，解决负极析锂问题，又降低了电极能量密度的损失，保证极片具有足够的能量密度。
在任意实施方式中，本申请第一方面的负极极片由本申请第二方面的方法制备。其中，负极集流体上第一区段的位置与负极膜层上第一区域的位置相对应，同时，负极集流体上第二区段的位置与负极膜层上第二区域的位置相对应。
本申请的第三方面提供一种二次电池，包括本申请第一方面的负极极片或根据本申请第二方面的方法制备的负极极片。
本申请的第四方面提供一种电池模块，包括本申请的第三方面的二次电池。
本申请的第五方面提供一种电池包，包括本申请的第四方面的电池模块。
本申请的第六方面提供一种用电装置，包括选自本申请的第三方面的二次电池、本申请的第四方面的电池模块和本申请的第五方面的电池包中的至少一种。
本申请取得了如下的有益效果：
本申请负极极片在少量电解液存在情况下仍可保证活性离子的正常脱嵌，解决了电解液挤出造成的负极析锂问题；本申请负极极片同时改善了电池的循环性能、存储性能和安全性能；本申请负极极片具有较高的能量密度。
附图说明
图1是本申请一实施方式的二次电池的示意图。
图2是图1所示的本申请一实施方式的二次电池的分解图。
图3是本申请一实施方式的电池模块的示意图。
图4是本申请一实施方式的电池包的示意图。
图5是图4所示的本申请一实施方式的电池包的分解图。
图6是本申请一实施方式的二次电池用作电源的用电装置的示意图。
图7为本申请实施例1-15中负极极片的结构示意图。
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。
具体实施方式
以下，适当地参照附图详细说明具体公开了本申请的负极极片及其制备方法、二次电池、电池模块、电池包和用电装置的实施方式。但是会有省略不必要的详细说明的情况。例如，有省略对已众所周知的事项的详细说明、实际相同结构的重复说明的情况。这是为了避免以下的说明不必要地变得冗长，便于本领域技术人员的理解。此外，附图及以下说明是为了本领域技术人员充分理解本申请而提供的，并不旨在限定权利要求书所记载的主题。
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。
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，可选是顺序进行的。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。
如果没有特别的说明，在本申请中，术语“或”是包括性的。举例来说，短语“A或B”表示“A，B，或A和B两者”。更具体地，以下任一条件均满足条件“A或B”：A为真(或存在)并且B为假(或不存在)；A为假(或不存在)而B为真(或存在)；或A和B都为真(或存在)。
[二次电池]
二次电池又称为充电电池或蓄电池，是指在电池放电后可通过充电的方式使活性材料激活而继续使用的电池。
通常情况下，二次电池包括正极极片、负极极片、隔离膜及电解液。在电池充放电过程中，活性离子(例如锂离子)在正极极片和负极极片之间往返嵌入和脱出。隔离膜设置在正极极片和负极极片之间，主要起到防止正负极短路的作用，同时可以使活性离子通过。电解液在正极极片和负极极片之间，主要起到传导活性离子的作用。
负极极片
负极极片通常包括负极集流体以及设置在负极集流体至少一个表面上的负极膜层，负极膜层包括负极活性材料。
作为示例，负极集流体具有在其自身厚度方向相对的两个表面， 负极膜层设置在负极集流体相对的两个表面中的任意一个或两个上。
电池在充放电过程中，负极极片会发生膨胀和收缩，导致电池内部应力分布不均；尤其是，充电过程中负极极片膨胀，导致电解液被挤出，放电过程中负极极片收缩，但电解液来不及回补，造成“电解液挤出”效应，影响了活性离子的正常脱嵌，导致负极容易发生析锂，从而影响电池的循环性能和安全性能。
基于上述问题，本申请的一个实施方式提供一种负极极片，包括负极集流体和负极膜层，负极膜层设置在负极集流体的至少一个表面上；负极膜层沿宽度方向包括第一区域和第二区域，第一区域不包含固态电解质，第二区域包含固态电解质。
目前，现有技术主要通过降低极片的膨胀力来改善“电解液挤出”效应，以解决负极析锂问题，但这种方法的改善效果有限；并且，随着市场对电芯能量密度需求的提高，硅材料作为主流的负极活性材料使用，但硅材料更易膨胀，难以通过降低膨胀力的方法解决析锂问题。本申请的负极极片在第二区域含有固态电解质，即便遇到电解液被挤出问题，在少量电解液存在的情况下仍可以保证活性离子的正常脱嵌，从根本上解决了电解液挤出所造成的负极析锂问题，减缓了电池容量的衰减速率，从而使电池同时具有良好的循环性能、存储性能和安全性能。
在一些实施方式中，第一区域沿负极膜层的宽度方向包括第一膜层区和第二膜层区，第二区域位于第一膜层区和第二膜层区之间；负极膜层的宽度记为L，第一膜层区的宽度记为L 1，第二区域的宽度记为L 2，第二膜层区的宽度记为L 3。本申请负极极片将含有固态电解质的第二区域设置在第一膜层区和第二膜层区之间，有效缓解了极片中部膨胀造成电解液挤出所引发的析锂问题，明显提高了电池的循环性能、存储性能和安全性。
在一些实施方式中，0<L 1/L≤0.75；可选地，0.3≤L 1/L≤0.55，例如0.1、0.125、0.2、0.3、0.375、0.4、0.45、0.5、0.55、0.6。
在一些实施方式中，0<L 3/L≤0.75；可选地，0.25≤L 3/L≤0.75，例 如0.1、0.125、0.2、0.3、0.375、0.4、0.45、0.5、0.55、0.6、0.7。
这样可以保证含有固态电解质的第二区域位于负极膜层的中间位置，解决了极片中部膨胀导致电解液挤出所带来的析锂问题，从而同时改善电池的循环性能、存储性能和安全性。
在一些实施方式中，0<L 2/L≤0.75；可选地，0.3≤L 2/L≤0.55，例如0.1、0.15、0.2、0.25、0.3、0.4、0.5、0.6、0.7、0.75。采用该宽度范围的含有固态电解质的第二区域，即便在电解液挤出的情况下仍能保持活性离子的正常脱嵌，降低负极析锂，使得本申请负极极片兼具良好的循环性能、存储性能和安全性，同时保持较高的能量密度。
在一些实施方式中，固态电解质在第二区域中的质量占比大于0且不大于30％，可选为15％-30％，例如2％、5％、8％、10％、15％、20％、25％。固态电解质在第二区域中的质量占比过大，容易造成极片能量密度的损失，限定质量占比大于0且不大于30％，既可以通过含有固态电解质的第二区域在电解液挤出的情况下保证活性离子的正常脱嵌，解决负极中部膨胀力大所造成的负极析锂问题，又降低了电极能量密度的损失，保证极片具有足够的能量密度。
在一些实施方式中，L 1＝L 3。这样设置方便了负极极片的加工，提高了负极极片的生产效率，同时使第二区域位于负极膜层沿宽度方向的中间，能更好地解决因负极极片中心膨胀力大所引起的负极析锂问题。
在一些实施方式中，L 1＝L 2＝L 3。进一步方便极片的加工，提高生产效率。
在一些实施方式中，第一区域和第二区域的厚度相等。这样设置可以保证负极膜层厚度的均匀性，有利于负极极片的正常使用，同时便于负极极片的加工制作。
在一些实施方式中，第一区域和第二区域的厚度为本领域负极膜层的常规的厚度，例如第一区域和第二区域的厚度为100-250μm。这样既可以保证负极极片的正常使用，又可以通过含固态电解质的第二区域保证活性离子的正常脱嵌，解决因负极中部膨胀力过大导致的负 极析锂问题。
在一些实施方式中，固态电解质为选自氧化物固态电解质、硫化物固态电解质和聚合物固态电解质中的至少一种。作为示例，氧化物固态电解质可包括以下的至少一种：LLZTO固态电解质、钙钛矿型Li 3.3La 0.56TiO 3、钠快离子导体型LiTi 2(PO 4) 3、锂快离子导体型Li 14Zn(GeO 4) 4、石榴石型Li 7La 3Zr 2O 12；硫化物固态电解质可包括以下的至少一种：Li 3PS 4、Li 6PS 5Cl、Li 10GeP 2S 12、Li 7P 3S 11；聚合物固态电解质可包括以下的至少一种：聚氧乙烯PEO、聚偏氟乙烯PVDF、聚丙烯腈PAN、聚甲基丙烯酸甲酯PMMA、聚乙烯吡咯烷酮PVP或聚偏二氟乙烯PVDF-HFP；但本申请并不限定于这些材料，还可以使用其他可被用作固态电解质的传统材料。这些固态电解质可以仅单独使用一种，也可以将两种以上组合使用。
在一些实施方式中，负极活性材料在第一区域中的质量占比采用本领域公知的负极膜层中负极活性材料质量占比。
在一些实施方式中，负极活性材料在第二区域中的质量占比为60％-95％，例如65％、68％、70.5％、75.5％、80.5％、85.5％、90.5％、92％。
在一些实施方式中，第一区域和第二区域均包含负极活性材料。第一区域和第二区域中的负极活性材料可采用本领域公知的用于电池的负极活性材料。可选地，第一区域和第二区域中的负极活性材料各自独立地选自人造石墨、天然石墨、软炭、硬炭、硅基材料、锡基材料和钛酸锂中的至少一种。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。
在一些实施方式中，硅基材料在第二区域中的质量占比为1％-8％，例如1.2％、2.3％、3.5％、4.5％、5.5％。这样，第二区域中除包含固态电解质外，还包含能量密度较大的硅基材料，以维持负极极片具有 较高的能量密度。
在一些实施方式中，第一区域的孔隙率≥24％；可选为24％-28％。
在一些实施方式中，第二区域的孔隙率≥20％；可选为20％-24％。
第一区域不包含固态电解质，极片上较大的孔隙率有利于锂离子的传输；同时，第二区域包含固态电解质，较小的孔隙率有利于提高固态电解质和活性材料的接触并保证锂离子传输；本申请针对使用电解液作为锂离子传输导体的体系，上述孔隙率既保证活性离子在负极极片中具有足够的扩散通道，又能满足极片不析锂的需求，同时能使极片得到充分浸润，以保证阳极材料的动力学，从而保证电池兼具较好的循环性能、存储性能和安全性。
在一些实施方式中，负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。
在一些实施方式中，第一区域和第二区域还可选地包括粘结剂。粘结剂可选自丁苯橡胶(SBR)、聚丙烯酸(PAA)、聚丙烯酸钠(PAAS)、聚丙烯酰胺(PAM)、聚乙烯醇(PVA)、海藻酸钠(SA)、聚甲基丙烯酸(PMAA)及羧甲基壳聚糖(CMCS)中的至少一种。
在一些实施方式中，粘结剂在第一区域和第二区域中的质量占比为本领域通常采用的负极膜层中的粘结剂质量占比。
在一些实施方式中，第一区域和第二区域还可选地包括导电剂。导电剂可选自超导碳、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。
在一些实施方式中，导电剂在第一区域和第二区域中的质量占比为本领域通常采用的负极膜层中的导电剂质量占比。
在一些实施方式中，第一区域和第二区域还可选地包括其他助剂， 例如增稠剂【如羧甲基纤维素钠(CMC-Na)】等。
负极极片的制备方法
在一些实施方式中，本申请还提出一种制备负极极片的方法，包括如下步骤：
将负极集流体的至少一个表面沿宽度方向分成第一区段和第二区段；
提供第一负极浆料和第二负极浆料，其中，第一负极浆料不包含固态电解质，第二负极浆料包含固态电解质；
将第一负极浆料涂布在第一区段，将第二负极浆料涂布在第二区段。
由此，制备的负极极片在少量电解液存在的情况下仍可以保证活性离子的正常脱嵌，缓解了电解液挤出所造成的负极析锂问题，从而使电池兼具良好的循环性能、存储性能和安全性能。
在一些实施方式中，将第一区段沿负极集流体的宽度方向分成第一部分和第二部分，第二区段位于第一部分和第二部分之间。这样，在第一部分和第二部分之间的第二区段上涂布含固态电解质的第二负极浆料以制备负极极片，有效缓解了极片中部的电解液挤出导致的析锂问题，明显提高了电池的循环性能、存储性能和安全性。
在一些实施方式中，第一部分与负极集流体的宽度之比为大于0且不大于0.75，可选为0.3-0.55，例如0.1、0.125、0.2、0.3、0.375、0.4、0.45、0.5、0.55、0.6。
在一些实施方式中，第二部分与负极集流体的宽度之比为大于0且不大于0.75，可选为0.25-0.75，例如0.1、0.125、0.2、0.3、0.375、0.4、0.45、0.5、0.55、0.6、0.7。
这样保证用于涂布第二浆料的第二区段位于极片中间位置，解决了极片中部膨胀所造成的析锂问题，从而改善了电池的循环性能、存储性能和安全性。
在一些实施方式中，第二区段与负极集流体的宽度之比为大于0且不大于0.75，可选为0.3-0.55，例如0.1、0.15、0.2、0.25、0.3、0.4、 0.5、0.6、0.7、0.75。采用该宽度范围的第二区段用于涂布含固态电解质的第二浆料，即便在电解液挤出的情况下仍能保持活性离子的正常脱嵌，降低负极析锂，使得本申请负极极片兼具良好的循环性能、存储性能和安全性，同时保持较高的能量密度。
在一些实施方式中，第一部分和第二部分的宽度相等。这一设置便于负极极片的制备和加工，提高了负极极片的生产效率，同时，这一设置能保证第二区段位于负极极片的中间，能更好地解决因负极极片中心膨胀力大所引起的负极析锂问题。
在一些实施方式中，第二负极浆料中固态电解质的质量含量为大于0且不大于30％，可选为15％-30％，例如2％、5％、8％、10％、15％、20％、25％。固态电解质在第二负极浆料中的质量占比过大，容易导致负极极片的能量密度损失，限定质量占比大于0且不超过30％，既可以保证本申请负极极片在电解液挤出的情况下维持锂离子的正常脱嵌，解决负极析锂问题，又降低了电极能量密度的损失，保证极片具有足够的能量密度。
在一些实施方式中，上述负极极片由本方法制备。其中，负极集流体上第一区段的位置与负极膜层上第一区域的位置相对应，同时，负极集流体上第二区段的位置与负极膜层上第二区域的位置相对应。
在一些实施方式中，第一负极浆料在第一区段上的涂布面密度为5-20mg/m 2，例如12mg/m 2。
在一些实施方式中，第二负极浆料在第二区段上的涂布面密度为8-25mg/m 2，例如16mg/m 2。
由此，可以保证负极膜层整体厚度的均匀性、一致性，有利于负极极片的正常使用，同时便于负极极片的制备。
在一些实施方式中，第一负极浆料通过将负极活性材料、可选的导电剂、可选的粘结剂和任意其他组分分散于溶剂中形成。
在一些实施方式中，第二负极浆料通过将固态电解质、负极活性材料、可选的导电剂、可选的粘结剂和任意其他组分分散于溶剂中形成。
在一些实施方式中，第一负极浆料和第二负极浆料中的负极活性材料可采用本领域公知的用于电池的负极活性材料。可选地，第一区域和第二区域中的负极活性材料各自独立地选自人造石墨、天然石墨、软炭、硬炭、硅基材料、锡基材料和钛酸锂中的至少一种。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。
在一些实施方式中，硅基材料在第二浆料中的质量占比为1％-8％，例如1.2％、2.3％、3.5％、4.5％、5.5％。这样可以维持负极极片具有较高的能量密度。
在一些实施方式中，第一负极浆料和第二负极浆料的固含量适于正常涂布以制备极片。
[正极极片]
正极极片通常包括正极集流体以及设置在正极集流体至少一个表面的正极膜层，正极膜层包括本申请第一方面的正极活性材料。
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。
在一些实施方式中，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。
在一些实施方式中，正极活性材料可采用本领域公知的用于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。
在一些实施方式中，正极膜层还可选地包括粘结剂。作为示例，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。
在一些实施方式中，正极膜层还可选地包括导电剂。作为示例，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。
在一些实施方式中，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。
[电解质]
电解质在正极极片和负极极片之间起到传导离子的作用。本申请 对电解质的种类没有具体的限制，可根据需求进行选择。例如，电解质可以是液态的、凝胶态的或全固态的。
在一些实施方式中，电解质为液态的，且包括电解质盐和溶剂。
在一些实施方式中，电解质盐可选自六氟磷酸锂、四氟硼酸锂、高氯酸锂、六氟砷酸锂、双氟磺酰亚胺锂、双三氟甲磺酰亚胺锂、三氟甲磺酸锂、二氟磷酸锂、二氟草酸硼酸锂、二草酸硼酸锂、二氟二草酸磷酸锂及四氟草酸磷酸锂中的至少一种。
在一些实施方式中，溶剂可选自碳酸亚乙酯、碳酸亚丙酯、碳酸甲乙酯、碳酸二乙酯、碳酸二甲酯、碳酸二丙酯、碳酸甲丙酯、碳酸乙丙酯、碳酸亚丁酯、氟代碳酸亚乙酯、甲酸甲酯、乙酸甲酯、乙酸乙酯、乙酸丙酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、丁酸甲酯、丁酸乙酯、1,4-丁内酯、环丁砜、二甲砜、甲乙砜及二乙砜中的至少一种。
在一些实施方式中，电解液还可选地包括添加剂。做为示例，添加剂可以包括负极成膜添加剂、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、改善电池高温或低温性能的添加剂等。
[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。
在一些实施方式中，二次电池可包括外包装。该外包装可用于封装上述电极组件及电解质。
在一些实施方式中，二次电池的外包装可以是硬壳，例如硬塑料 壳、铝壳、钢壳等。二次电池的外包装也可以是软包，例如袋式软包。软包的材质可以是塑料，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。
本申请对二次电池的形状没有特别的限制，其可以是圆柱形、方形或其他任意的形状。例如，图1是作为一个示例的方形结构的二次电池5。
在一些实施方式中，参照图2，外包装可包括壳体51和盖板53。其中，壳体51可包括底板和连接于底板上的侧板，底板和侧板围合形成容纳腔。壳体51具有与容纳腔连通的开口，盖板53能够盖设于开口，以封闭容纳腔。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封装于容纳腔内。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，本领域技术人员可根据具体实际需求进行选择。
在一些实施方式中，二次电池可以组装成电池模块，电池模块所含二次电池的数量可以为一个或多个，具体数量本领域技术人员可根据电池模块的应用和容量进行选择。
图3是作为一个示例的电池模块4。参照图3，在电池模块4中，多个二次电池5可以是沿电池模块4的长度方向依次排列设置。当然，也可以按照其他任意的方式进行排布。进一步可以通过紧固件将该多个二次电池5进行固定。
可选地，电池模块4还可以包括具有容纳空间的外壳，多个二次电池5容纳于该容纳空间。
在一些实施方式中，上述电池模块还可以组装成电池包，电池包所含电池模块的数量可以为一个或多个，具体数量本领域技术人员可根据电池包的应用和容量进行选择。
图4和图5是作为一个示例的电池包1。参照图4和图5，在电池包1中可以包括电池箱和设置于电池箱中的多个电池模块4。电池箱包括上箱体2和下箱体3，上箱体2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。
另外，本申请还提供一种用电装置，用电装置包括本申请提供的二次电池、电池模块、或电池包中的至少一种。二次电池、电池模块、或电池包可以用作用电装置的电源，也可以用作用电装置的能量存储单元。用电装置可以包括移动设备(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，但不限于此。
作为用电装置，可以根据其使用需求来选择二次电池、电池模块或电池包。
图6是作为一个示例的用电装置。该用电装置为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了满足该用电装置对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。
实施例
以下，说明本申请的实施例。下面描述的实施例是示例性的，仅用于解释本申请，而不能理解为对本申请的限制。实施例中未注明具体技术或条件的，按照本领域内的文献所描述的技术或条件或者按照产品说明书进行。所用试剂或仪器未注明生产厂商者，均为可以通过市购获得的常规产品。
实施例1-15和对比例1-3
1、制备正极极片：将正极活性材料三元NCM811、粘结剂聚偏氟乙烯(PVDF)、导电剂乙炔黑和导电剂碳纳米管按照95.5:2:2:0.5的质量比溶于N-甲基吡咯烷酮(NMP)中，充分搅拌均匀，得到正极浆料；将正极浆料均匀涂覆在正极集流体铝箔上，经烘干、冷压、分切，得到正极极片。
2、制备负极极片：
(1)制备负极浆料1：将负极活性材料石墨、导电剂乙炔黑、粘结剂丁苯橡胶(SBR)、增稠剂羧甲基纤维素钠(CMC-Na)按照 95.5:2:1.5:1的质量比溶于去离子水中，充分搅拌均匀，得到负极浆料1；
(2)制备负极浆料2：将负极活性材料石墨、氧化亚硅、导电剂乙炔黑、粘结剂丁苯橡胶(SBR)、增稠剂羧甲基纤维素钠(CMC-Na)按照95:0.5:2:1.5:1的质量比溶于去离子水中，充分搅拌均匀，得到负极浆料2；
(3)制备负极浆料3：将负极活性材料石墨、氧化亚硅、固态电解质LLZTO、导电剂乙炔黑、粘结剂丁苯橡胶(SBR)、增稠剂羧甲基纤维素钠(CMC-Na)按照89.3:1.2:5:2:1.5:1的质量比溶于去离子水中，充分搅拌均匀，得到负极浆料3；
(4)制备负极浆料4：将负极活性材料石墨、氧化亚硅、固态电解质LLZTO、导电剂乙炔黑、粘结剂丁苯橡胶(SBR)、增稠剂羧甲基纤维素钠(CMC-Na)按照83.2:2.3:10:2:1.5:1的质量比溶于去离子水中，充分搅拌均匀，得到负极浆料4；
(5)制备负极浆料5：将负极活性材料石墨、氧化亚硅、固态电解质LLZTO、导电剂乙炔黑、粘结剂丁苯橡胶(SBR)和增稠剂羧甲基纤维素钠(CMC-Na)按照77:3.5:15:2:1.5:1的质量比溶于去离子水中，充分搅拌均匀，得到负极浆料5；
(6)制备负极浆料6：将负极活性材料石墨、氧化亚硅、固态电解质LLZTO、导电剂乙炔黑、粘结剂丁苯橡胶(SBR)、增稠剂羧甲基纤维素钠(CMC-Na)按照71:4.5:20:2:1.5:1的质量比溶于去离子水中，充分搅拌均匀，得到负极浆料6；
(7)制备负极浆料7：将负极活性材料石墨、氧化亚硅、固态电解质LLZTO、导电剂乙炔黑、粘结剂丁苯橡胶(SBR)和增稠剂羧甲基纤维素钠(CMC-Na)按照65:5.5:25:2:1.5:1的质量比溶于去离子水中，充分搅拌均匀，得到负极浆料7；
将负极集流体铜箔分为三个涂膜区，将负极浆料涂布在三个涂膜区的铜箔上，经烘干、冷压、分切，得到负极极片；如图7所示，负极极片的负极膜层相应地分为三个部分，第一膜层区的宽度为L1， 第二区域的宽度为L2，第二膜层区的宽度为L3，负极膜层的总宽度为L，第一膜层区、第二区域和第二膜层区的厚度均为160μm(冷压后)。
实施例1-15及对比例1-3的不同工艺参数如表1所示。
表1
Figure PCTCN2021131507-appb-000001
Figure PCTCN2021131507-appb-000002
3、隔离膜：采用聚丙烯膜。
4、制备电解液：将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)和碳酸二乙酯(DEC)按1:1:1的体积比配成溶液，将LiPF 6均匀溶解在上述溶液中，得到电解液，其中，LiPF 6的浓度为1.2mol/L。
硬壳电池的制作
分别采用实施例1至15、对比例1-3的负极极片，采用前面制作的正极极片，使用厚度为16μm的聚乙烯膜作为隔离膜，将负极极片、隔离膜、正极极片进行卷绕和极耳焊接，组装成硬壳电池，经过注液(采用制备的上述电解液)，首次充电，制成备用的硬壳电池1-15，A-C，电芯的容量为7000mAh。
电池测试
测定硬壳电池1-15、A、B、C的循环性能，为了模拟硬壳电池在模组中的实际情况，采用钢板夹具夹住硬壳电池的两侧面进行测试。
1)将电池反复充放电，直至容量衰减至90％，记录电池的循环圈数，充电倍率为0.1C，放电倍率为0.5C，需指出的是，上述充放电倍率下硬壳电池可正常使用；
2)第1)项中的循环结束后，采用拆解电池的方法检测电池的析锂情况；
3)将电池满充至4.25V电压上限，在60℃下存储100天，测试电池的存储容量保持率。
以上各项结果如表2中所示。
表2电池循环测试结果
Figure PCTCN2021131507-appb-000003
Figure PCTCN2021131507-appb-000004
由表2可知：
本申请实施例1-5的结果表明：相比于对比例2，随着第二区域中固态电解质含量的增加，电池的循环圈数明显增加，当固态电解质含量达到15％(实施例3)时，电池的循环圈数达到最高值429圈，随着固态电解质含量进一步增加，电池的循环圈数逐渐减少，但仍优于对比例1和2；相比于对比例3，本申请负极极片的第一膜层区和第二膜层区不含固态电解质，电池的存储容量保持率明显改善；第二区域中固态电解质的含量不低于15％(实施例3-5)，电池不发生析锂；同时，伴随固态电解质含量的逐渐增加，氧化亚硅含量也逐渐增加，以维持电池的能量密度。
本申请实施例6-10的结果表明：相比于对比例2，随着含固态电解质的第二区域的宽度由1/10L增加至1/4L，电池的循环圈数逐渐增加，宽度为1/4L时(实施例8)电池的循环圈数达到最高值442圈，随后伴随宽度的增加，电池的循环圈数逐渐减小，但仍高于对比例1-2；相比于对比例3，电池的存储容量保持率明显改善；第二区域的宽度≥1/4L，电池不发生析锂。
本申请实施例8、实施例11-15表明：第二区域位于负极极片宽度方向的中间位置时，电池的循环圈数最多，电池不析锂，整体性能表现最佳；当第一膜层区和第二膜层区采用纯石墨作为活性材料时，电池的循环与存储性能进一步改善，电池不发生析锂。
综上所述，本申请负极极片能明显改善电池的循环性能和电池的存储性能。本申请负极极片可选固态电解质含量不低于15％、第二区域的宽度L 2≥1/4L，电池不发生析锂。本申请负极极片的第二区域的 宽度L 2＝1/4L时，能量密度较高，综合效果最佳。
需要说明的是，本申请不限定于上述实施方式。上述实施方式仅为示例，在本申请的技术方案范围内具有与技术思想实质相同的构成、发挥相同作用效果的实施方式均包含在本申请的技术范围内。此外，在不脱离本申请主旨的范围内，对实施方式施加本领域技术人员能够想到的各种变形、将实施方式中的一部分构成要素加以组合而构筑的其它方式也包含在本申请的范围内。

Claims (23)

  1. 一种负极极片，包括负极集流体和负极膜层，所述负极膜层设置在所述负极集流体的至少一个表面上；所述负极膜层沿宽度方向包括第一区域和第二区域，所述第一区域不包含固态电解质，所述第二区域包含固态电解质。
  2. 根据权利要求1所述的负极极片，其中，所述第一区域沿所述负极膜层的宽度方向包括第一膜层区和第二膜层区，所述第二区域位于所述第一膜层区和所述第二膜层区之间；所述负极膜层的宽度记为L，所述第一膜层区的宽度记为L 1，所述第二区域的宽度记为L 2，所述第二膜层区的宽度记为L 3。
  3. 根据权利要求2所述的负极极片，其中，0<L 1/L≤0.75；可选地，0.3≤L 1/L≤0.55。
  4. 根据权利要求2或3所述的负极极片，其中，0<L 3/L≤0.75；可选地，0.25≤L 3/L≤0.75。
  5. 根据权利要求2至4中任一项所述的负极极片，其中，0<L 2/L≤0.75；可选地，0.3≤L 2/L≤0.55。
  6. 根据权利要求1至5中任一项所述的负极极片，其中，所述固态电解质在所述第二区域中的质量占比为大于0且不大于30％，可选为15％-30％。
  7. 根据权利要求2至6中任一项所述的负极极片，其中，L 1＝L 3。
  8. 根据权利要求2至7中任一项所述的负极极片，其中，L 1＝L 2＝L 3。
  9. 根据权利要求1至8中任一项所述的负极极片，其中，所述固态电解质为选自氧化物固态电解质、硫化物固态电解质和聚合物固态电解质中的至少一种。
  10. 根据权利要求1至9中任一项所述的负极极片，其中，所述第一区域和所述第二区域均包含负极活性材料；
    可选地，所述第一区域和所述第二区域中的负极活性材料各自独立地选自人造石墨、天然石墨、软炭、硬炭、硅基材料、锡基材料和钛酸锂中的至少一种。
  11. 根据权利要求1至10中任一项所述的负极极片，其中，所述第一区域的孔隙率≥24％；可选为24％-28％。
  12. 根据权利要求1至11中任一项所述的负极极片，其中，所述第二区域的孔隙率≥20％；可选为20％-24％。
  13. 一种制备负极极片的方法，包括如下步骤：
    将负极集流体的至少一个表面沿宽度方向分成第一区段和第二区段；
    提供第一负极浆料和第二负极浆料，其中，所述第一负极浆料不包含固态电解质，所述第二负极浆料包含固态电解质；
    将第一负极浆料涂布在所述第一区段，将第二负极浆料涂布在所述第二区段。
  14. 根据权利要求13所述的方法，其还包括：将所述第一区段沿所述负极集流体的宽度方向分成第一部分和第二部分，所述第二区 段位于所述第一部分和所述第二部分之间。
  15. 根据权利要求13或14所述的方法，其中，所述第一部分与所述负极集流体的宽度之比为大于0且不大于0.75，可选为0.3-0.55。
  16. 根据权利要求13至15中任一项所述的方法，其中，所述第二部分与所述负极集流体的宽度之比为大于0且不大于0.75，可选为0.25-0.75。
  17. 根据权利要求13至16中任一项所述的方法，其中，所述第二区段与所述负极集流体的宽度之比为大于0且不大于0.75，可选为0.3-0.55。
  18. 根据权利要求13至17中任一项所述的方法，其中，所述第一部分和所述第二部分的宽度相等。
  19. 根据权利要求13至18中任一项所述的方法，其中，所述第二负极浆料中固态电解质的质量含量为大于0且不大于30％，可选为15％-30％。
  20. 一种二次电池，其特征在于，包括权利要求1至12中任一项所述的负极极片或通过权利要求13至19中任一项所述方法制得的负极极片。
  21. 一种电池模块，其特征在于，包括权利要求20所述的二次电池。
  22. 一种电池包，其特征在于，包括权利要求21所述的电池模块。
  23. 一种用电装置，其特征在于，包括选自权利要求20所述的二次电池、权利要求21所述的电池模块和权利要求22所述的电池包中的至少一种。
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