WO2023092293A1 - 一种电极组件、二次电池、电池模块、电池包及用电装置 - Google Patents

一种电极组件、二次电池、电池模块、电池包及用电装置 Download PDF

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WO2023092293A1
WO2023092293A1 PCT/CN2021/132493 CN2021132493W WO2023092293A1 WO 2023092293 A1 WO2023092293 A1 WO 2023092293A1 CN 2021132493 W CN2021132493 W CN 2021132493W WO 2023092293 A1 WO2023092293 A1 WO 2023092293A1
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active material
negative electrode
electrode active
material layer
positive electrode
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PCT/CN2021/132493
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English (en)
French (fr)
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姚斌
黄瑛
石蕊英
刘江
陈雪芳
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宁德时代新能源科技股份有限公司
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Priority to PCT/CN2021/132493 priority Critical patent/WO2023092293A1/zh
Priority to CN202180092811.7A priority patent/CN116830315A/zh
Priority to EP21954418.6A priority patent/EP4210132A1/en
Priority to US18/197,108 priority patent/US11791460B2/en
Publication of WO2023092293A1 publication Critical patent/WO2023092293A1/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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • H01M4/366—Composites as layered products
    • 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
    • H01M4/36—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
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • 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
    • 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
    • H01M4/624—Electric conductive 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
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/663—Selection of materials containing carbon or carbonaceous materials as conductive part, e.g. graphite, carbon fibres
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/204—Racks, modules or packs for multiple batteries or multiple cells
    • H01M50/207—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape
    • H01M50/209—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape adapted for prismatic or rectangular cells
    • 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
    • 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
    • H01M2004/028—Positive 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
    • 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
    • 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 field of lithium batteries, in particular to an electrode assembly, a secondary battery, a battery module, a battery pack and an electrical device.
  • Lithium-ion batteries have the advantages of long cycle life, small size, light weight, and good safety, and are widely used in various fields such as portable electronic devices, electric energy storage, and electric vehicles.
  • This application was made in view of the said subject, and it aims at improving the energy density of a lithium ion battery.
  • the present application provides an electrode assembly, a secondary battery, a battery module, a battery pack and an electrical device.
  • the first aspect of the present application provides an electrode assembly, which includes a positive pole piece and a negative pole piece; wherein, the positive pole piece includes a positive current collector and a positive active material disposed on at least one side surface of the positive current collector layer, the positive electrode active material layer includes a positive electrode active material and a quinone compound; the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer arranged on at least one side surface of the negative electrode current collector, and the negative electrode active material layer Including negative electrode active material and polymer conductive material; wherein, based on the quality of the positive electrode active material layer, the mass content mc % of the quinone compound is 0.5% to 3%; the gram capacity of the quinone compound is Cap C ; the gram capacity of the positive electrode active material is Cap; based on the quality of the negative electrode active material layer, the mass content of the polymer conductive material is mA %, which meets the following relationship:
  • the quinone compound included in the positive electrode active material layer of the positive electrode sheet provides additional lithium intercalation vacancies to improve the lithium storage capacity of the positive electrode sheet;
  • the polymer conductive material included in the negative electrode active material layer is used to improve the power of the negative electrode sheet Improve the chemical performance and improve the content of lithium released from the lithium-ion battery when the battery is discharged.
  • the quinone compound includes at least one of benzoquinone and its derivatives, naphthoquinone and its derivatives, and anthraquinone and its derivatives.
  • the polymer conductive material includes at least one of polyaniline, polypyrrole, polythiophene, polyethylene oxide, polyacrylonitrile, polyphenylene and polyacetylene.
  • the surface density of the positive electrode active material layer is 16.2 mg/cm 2 to 40.0 mg/cm 2 ; the surface density of the negative electrode active material layer is 5.8 mg/cm 2 to 18.0 mg/cm 2 .
  • the positive electrode active material layer includes multiple layers of positive electrode active material layers stacked in sequence along the direction away from the positive electrode current collector, wherein at least one of the multiple layers of positive electrode active material layers includes the the quinone compounds.
  • the outermost positive electrode active material layer of the multilayer positive electrode active material layer away from the positive electrode current collector contains the quinone compound, and the rest of the positive electrode active material layers may or may not contain all the positive electrode active material layers. the quinone compounds. Optionally, the remaining positive electrode active material layers do not contain quinone compounds.
  • the negative electrode active material layer includes m layers of negative electrode active material layers stacked in sequence away from the negative electrode current collector, and the n layers of negative electrode active material layers near the negative electrode current collector contain the high Molecular conductive material, wherein m/3 ⁇ n ⁇ m, m is a positive integer greater than or equal to 2, and n is a positive integer greater than or equal to 1.
  • the negative electrode active material layer comprises two negative electrode active material layers, the first negative electrode active material layer close to the negative electrode current collector comprises the first graphite, and the second negative electrode away from the negative electrode current collector
  • the sub-active material layer includes second graphite, and the difference between the gram capacity of the second graphite and the gram capacity of the first graphite is greater than or equal to 8mAh/g.
  • the negative electrode active material layer comprises two negative electrode active material layers, the first negative electrode active material layer close to the negative electrode current collector comprises the first graphite, and the second negative electrode away from the negative electrode current collector
  • the sub-active material layer comprises second graphite, the difference between the gram capacity of the second graphite and the gram capacity of the first graphite is less than 8mAh/g, and the specific surface area BET2 of the second graphite is greater than the specific surface area BET1 of the first graphite, preferably Generally, BET1 is 0.2m 2 /g to 0.8m 2 /g, and BET2 is 1m 2 /g to 2m 2 /g.
  • the negative electrode active material layer comprises two negative electrode active material layers, the first negative electrode active material layer close to the negative electrode current collector comprises graphite, and the second negative electrode active material layer far away from the negative electrode current collector The material layer contains SiO.
  • the positive electrode active material includes at least one of lithium iron phosphate, lithium manganese oxide, lithium nickel cobalt manganese oxide, lithium cobalt oxide and nickel manganese spinel;
  • the negative electrode active material includes graphite, hard At least one of carbon, molybdenum disulfide, silicon, silicon oxide, ferric oxide, tin oxide and titanium dioxide.
  • a second aspect of the present application provides a secondary battery including the electrode assembly of the first aspect of the present application.
  • a third aspect of the present application provides a battery module including the secondary battery of the second aspect of the present application.
  • a fourth aspect of the present application provides a battery pack, including the battery module of the third aspect of the present application.
  • the fifth aspect of the present application provides an electric device, including at least one selected from the secondary battery of the second aspect of the present application, the battery module of the third aspect of the present application, or the battery pack of the fourth aspect of the present application. kind.
  • the application provides an electrode assembly, a secondary battery, a battery module, a battery pack, and an electrical device, and the quinone compound included in the positive electrode active material layer provides additional lithium intercalation vacancies to improve the performance of the positive electrode sheet.
  • Lithium storage capacity; the polymer conductive material included in the negative electrode active material layer is used to improve the dynamic performance of the negative electrode sheet and increase the content of lithium extracted from the lithium ion battery during discharge.
  • the addition ratio of quinone compounds and conductive polymers By synergistically controlling the addition ratio of quinone compounds and conductive polymers, the energy density of lithium-ion batteries can be improved.
  • any product or method of the present application does not necessarily need to achieve all the above-mentioned advantages at the same time.
  • FIG. 1 is a schematic diagram of a positive electrode sheet according to an embodiment of the present application.
  • FIG. 2 is a schematic diagram of a secondary battery according to an embodiment of the present application.
  • FIG. 3 is an exploded view of the secondary battery according to one embodiment of the present application shown in FIG. 2 .
  • FIG. 4 is a schematic diagram of a battery module according to an embodiment of the present application.
  • FIG. 5 is a schematic diagram of a battery pack according to an embodiment of the present application.
  • FIG. 6 is an exploded view of the battery pack according to one embodiment of the present application shown in FIG. 5 .
  • FIG. 7 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.
  • 1 negative electrode current collector 2 first negative electrode active material layer; 3 second negative electrode active material layer; 4 battery module; 5 secondary battery; 51 shell; 52 electrode assembly; Upper casing; 12 lower casings.
  • 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.
  • steps (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).
  • the application provides an electrode assembly, a secondary battery, a battery Modules, battery packs and electrical devices.
  • the present application proposes an electrode assembly, including a positive pole piece and a negative pole piece, wherein the positive pole piece includes a positive current collector and a positive active material layer disposed on at least one side surface of the positive current collector , the positive electrode active material layer includes a positive electrode active material and a quinone compound.
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer arranged on at least one side surface of the negative electrode current collector.
  • the negative electrode active material layer includes a negative electrode active material and a polymer conductive material; wherein, based on the quality of the positive electrode active material layer, the quinone compound The mass content mc% is 0.5% to 3%; the gram capacity of the quinone compound is Cap C ; the gram capacity of the positive electrode active material is Cap; based on the quality of the negative electrode active material layer, the mass content of the polymer conductive material is mA % , conforming to the following relationship:
  • the applicant has found through research that the quinone compound included in the positive electrode active material layer can provide additional lithium intercalation vacancies and improve the lithium storage capacity of the positive electrode sheet; the polymer conductive material included in the negative electrode active material layer is used for Improve the kinetic performance of the negative pole piece, and increase the content of lithium extracted from the lithium-ion battery during discharge.
  • the addition ratio of quinone compounds and conductive polymers By synergistically controlling the addition ratio of quinone compounds and conductive polymers, the energy density of lithium-ion batteries can be improved.
  • the quinone compound includes at least one of benzoquinone and its derivatives, naphthoquinone and its derivatives, and anthraquinone and its derivatives.
  • the conductive polymer material includes at least one of polyaniline, polypyrrole, polythiophene, polyethylene oxide, polyacrylonitrile, polyphenylene and polyacetylene.
  • the areal density of the positive electrode active material layer is 16.2 mg/cm 2 to 40.0 mg/cm 2 , for example, the areal density of the positive electrode active material layer can be 20.0 mg/cm 2 , 24.0 mg/cm 2 , 28.0 mg/cm 2 , 32.0 mg/cm 2 , 36.0 mg/cm 2 or any range therebetween.
  • the applicant found that when the areal density of the positive electrode active material layer is too low, for example, less than 16.2 mg/cm 2 , the pole piece will become longer with the same capacity, and the amount of substrate will increase, which is not conducive to the improvement of energy density.
  • the surface density of the positive electrode active material layer is too high, such as higher than 40.0mg/cm 2 , due to the increased time and force required for thickness compression in the processing of the pole piece, it is difficult to press to a higher compaction, which reduces the compaction, which is not conducive to Increased energy density.
  • the energy density of the lithium ion battery can be increased.
  • the areal density of the negative electrode active material layer is 5.8 mg/cm 2 to 18.0 mg/cm 2 , for example, the areal density of the negative electrode active material layer can be 6.0 mg/cm 2 , 8.0 mg/cm 2 , 10.0 mg/cm 2 mg/cm 2 , 12.0 mg/cm 2 , 14.0 mg/cm 2 , 16.0 mg/cm 2 or any range therebetween.
  • the applicant found that when the surface density of the negative electrode active material layer is too low, for example, less than 5.8mg/cm 2 , the pole piece will become longer at the same capacity, and the amount of substrate will increase, which is not conducive to the improvement of energy density.
  • the surface density of the negative electrode active material layer is too high, such as higher than 18.0mg/cm 2 , due to the increased time and force required for thickness compression in the processing of the pole piece, it is difficult to press to a higher compaction, which reduces the compaction, which is not conducive to Increased energy density.
  • the energy density of the lithium ion battery can be increased.
  • the positive electrode active material layer includes multiple layers of positive electrode active material layers stacked in sequence, wherein at least one of the multiple layers of positive electrode active material layers includes a quinone compound.
  • the outermost positive electrode active material layer of the multilayer positive electrode active material layer away from the positive electrode current collector contains quinone compounds, and the remaining positive electrode active material layers may or may not contain quinone compounds. Optionally, the remaining positive electrode active material layers do not contain quinone compounds.
  • the inventors have found, without being bound by any theory, that by arranging the outermost positive electrode active material layer of the multilayer positive electrode active material layer away from the positive electrode current collector to contain a quinone compound, that is, the quinone compound is placed away from the positive electrode current collector, the lithium can be shortened.
  • the migration path of lithium ions during discharge of lithium-ion batteries reduces polarization, enhances the lithium-intercalation ability of quinone compounds during discharge of lithium-ion batteries, and increases the energy density of lithium-ion batteries.
  • the negative electrode active material layer includes m layers of negative electrode active material layers stacked in sequence away from the direction of the negative electrode current collector, and the n layers of negative electrode active material layers close to the negative electrode current collector contain polymer conductive materials, wherein m/ 3 ⁇ n ⁇ m, m is a positive integer greater than or equal to 2, and n is a positive integer greater than or equal to 1.
  • the n-layer negative electrode active material layer arranged near the negative electrode current collector contains a polymer conductive material, that is, the polymer conductive material is arranged close to the negative electrode current collector, which can improve the power of the negative electrode active material layer near the negative electrode current collector in the negative electrode active material layer. Improve the chemical performance, increase the content of lithium extracted from the negative electrode sheet during discharge, and increase the energy density of the lithium-ion battery.
  • the m layers of negative electrode active material layers may all include polymer conductive materials.
  • an ion pathway can be formed throughout the entire negative electrode active material layer, which can fully improve the dynamic performance of the entire negative electrode sheet and improve the performance of the negative electrode sheet. Lithium content is extracted during discharge, resulting in a Li-ion battery with good energy density.
  • the negative electrode active material layer comprises two negative electrode active material layers, including the first negative electrode active material layer 2 close to the negative electrode current collector 1 and the second negative electrode away from the negative electrode current collector 1
  • the sub-active material layer 3, the first negative sub-active material layer 2 close to the negative current collector 1 comprises the first graphite
  • the second negative sub-active material layer 3 away from the negative current collector 1 comprises the second graphite
  • the gram capacity of the second graphite The difference with the gram capacity of the first graphite is greater than or equal to 8mAh/g.
  • the difference between the gram capacity Cap2 of the second graphite and the gram capacity Cap1 of the first graphite is greater than or equal to 8mAh/g, that is, Cap2-Cap1 ⁇ 8mAh/g, the negative electrode current collector surface
  • the second graphite can provide more lithium intercalation vacancies, avoiding lithium precipitation due to insufficient vacancies, so as to obtain lithium-ion batteries with high energy density.
  • the negative electrode active material layer comprises two negative electrode active material layers, the first negative electrode active material layer close to the negative electrode current collector comprises the first graphite, and the second negative electrode active material layer far away from the negative electrode current collector comprises the second negative electrode active material layer.
  • Two graphites the difference between the gram capacity Cap2 of the second graphite and the gram capacity Cap1 of the first graphite is less than 8mAh/g, that is, Cap2-Cap1 ⁇ 8mAh/g, the specific surface area BET2 of the second graphite is greater than the specific surface area BET1 of the first graphite,
  • BET1 is 0.2m 2 /g-0.8m 2 /g
  • BET2 is 1m 2 /g-2m 2 /g.
  • the difference between the gram capacity of the second graphite and the gram capacity of the first graphite is less than 8mAh/g
  • the specific surface area BET2 of the second graphite is set to be greater than or equal to the specific surface area BET1 of the first graphite
  • the negative electrode The second graphite on the surface of the current collector has better kinetic performance, avoiding lithium deposition on the surface of the anode due to insufficient kinetics, and improving the energy density of the lithium-ion battery.
  • the negative electrode active material layer comprises two negative electrode active material layers
  • the first negative electrode active material layer close to the negative electrode current collector comprises graphite
  • the second negative electrode active material layer away from the negative electrode current collector contains SiO.
  • the specific surface area of graphite is 0.2m 2 /g-2m 2 /g
  • the specific surface area of SiO is 0.5m 2 /g-3m 2 /g.
  • the positive electrode active material includes at least one of lithium iron phosphate, lithium manganese oxide, lithium nickel cobalt manganese oxide, lithium cobalt oxide, and nickel manganese spinel.
  • the negative electrode active material includes at least one of graphite, hard carbon, molybdenum disulfide, silicon, silicon oxide, ferric oxide, tin oxide and titanium dioxide.
  • a secondary battery which includes the electrode assembly described in any one of the above embodiments.
  • the secondary battery in the present application may refer to the lithium-ion battery described in any of the above-mentioned embodiments.
  • a secondary battery typically includes a positive pole piece, a negative pole piece, an electrolyte, and a separator.
  • active ions are intercalated and extracted back and forth between the positive electrode and the negative electrode.
  • the electrolyte plays the role of conducting ions between the positive pole piece and the negative pole piece.
  • 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 ions to pass through.
  • the positive pole piece includes a positive current collector and a positive active material layer arranged on at least one surface of the positive current collector.
  • the positive electrode current collector has two opposing surfaces in its own thickness direction, and the positive electrode active material layer is disposed on any one or both of the two opposing surfaces of the positive electrode current collector.
  • the positive electrode current collector can be a metal foil or a composite 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 active material layer optionally includes a binder.
  • 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.
  • the positive active material layer may optionally further 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
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector, and the negative electrode active material 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 active material layer is disposed on any one or both of the two opposing surfaces of the negative electrode current collector.
  • the negative electrode current collector can use a metal foil or a composite 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 negative active material layer optionally includes a binder.
  • the binder can be selected from styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), poly At least one of methacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).
  • the negative active material layer may 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 negative electrode active material layer may optionally include other additives, such as thickeners (such as sodium carboxymethylcellulose (CMC-Na)) and the like.
  • thickeners such as sodium carboxymethylcellulose (CMC-Na)
  • the negative electrode sheet can be prepared in the following manner: the above-mentioned components used to prepare the negative electrode sheet, such as negative electrode active material, conductive agent, binder and any other components, are dispersed 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 sheet can be obtained.
  • a solvent such as deionized water
  • the electrolyte plays the role of conducting ions between the positive pole piece and the negative pole piece.
  • the present application has no specific limitation on the type of electrolyte, which can be selected according to requirements.
  • electrolytes can be liquid, gel or all solid.
  • the electrolyte is an electrolytic solution.
  • the electrolyte solution 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 may optionally include additives.
  • 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 batteries, 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 packaging of the secondary battery may be a hard case, such as a hard plastic case, aluminum case, steel case, and the like.
  • the outer packaging of the secondary battery may also be a soft bag, such as a bag-type soft bag.
  • the material of the soft case may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, polybutylene succinate, and the like.
  • FIG. 2 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 accommodating cavity. Electrolyte is infiltrated in the electrode assembly 52 .
  • the number of electrode assemblies 52 contained in the secondary battery 5 can be one or 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. 4 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 further include a case having an accommodation 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.
  • FIGS. 5 and 6 show the battery pack 10 as an example.
  • a battery box and a plurality of battery modules 4 disposed in the battery box may be included in the battery pack 10 .
  • the battery box includes an upper box body 11 and a lower box body 12 , the upper box body 11 can cover the lower box body 12 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 electric device, which includes at least one of the secondary battery, battery module, or battery pack provided in the present application.
  • the secondary battery, battery module, or battery pack can be used as a power source of the electric device, and can also be used as an energy storage unit of the electric device.
  • the electric devices may include mobile devices (such as mobile phones, notebook computers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, etc.) , electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but not limited thereto.
  • a secondary battery, a battery module or a battery pack can be selected according to its use requirements.
  • FIG. 7 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.
  • a device may be a cell phone, tablet, laptop, or the like.
  • the device is generally required to be light and thin, and a secondary battery can be used as a power source.
  • the positive electrode slurry is evenly coated on one surface of an aluminum foil with a thickness of 13 ⁇ m, the surface density of the positive electrode active material layer is 26.0 mg/cm 2 , dried at 120 ° C, and the compaction of the positive electrode active material layer is obtained after cold pressing
  • the positive pole piece with a density of 2.4g/cm 3 is then processed through lug forming, slitting and other processes to obtain a positive pole piece with a width of 180mm.
  • the non-aqueous organic solvents ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate are mixed according to a volume ratio of 1:1:1 to obtain an electrolyte solvent with a mass of 450g, and then the lithium salt LiPF 6 is dissolved in the mixed solvent and configured as an electrolyte solution with a lithium salt concentration of 1mol/L.
  • a polyethylene with a thickness of 12 ⁇ m was selected as the isolation film, and the isolation film with a width of 188 mm was obtained by cutting.
  • the positive electrode slurry is uniformly coated on one surface of an aluminum foil with a thickness of 13 ⁇ m, the surface density of the positive electrode active material layer is 21.4 mg/cm 2 , dried at 120 ° C, and the compaction of the positive electrode active material layer is obtained after cold pressing
  • the positive pole piece with a density of 3.4g/cm 3 is then processed through lug forming, slitting and other processes to obtain a positive pole piece with a width of 180mm.
  • Negative electrode active material graphite, conductive agent conductive carbon black, binder sodium carboxymethyl cellulose (CMC), binder styrene-butadiene rubber, polythiophene are mixed according to the mass ratio 94.5:1:1:2:1.5, add to Ionized water was used as a solvent, and was stirred under the action of a vacuum mixer until the system was uniform, and a negative electrode slurry with a solid content of 54 wt% was obtained.
  • the negative electrode slurry is uniformly coated on one surface of a copper foil with a thickness of 8 ⁇ m, the surface density of the negative electrode active material layer is 12.0 mg/cm 2 , dried at 110 ° C, and the pressed material of the negative electrode active material layer is obtained after cold pressing.
  • the negative electrode sheet with a solid density of 1.65g/cm 3 is then processed by lug forming, slitting and other processes to obtain a negative electrode sheet with a width of 183mm.
  • the positive electrode active material LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523), the conductive agent conductive carbon black, and the binder polyvinylidene fluoride (PVDF) were mixed in a mass ratio of 97:1:2, and then N-methylpyrrolidone ( NMP) was used as a solvent, and was stirred under the action of a vacuum mixer until the system was uniform, and the first positive electrode slurry with a solid content of 75 wt% was obtained.
  • NMP N-methylpyrrolidone
  • LiFePO 4 lithium iron phosphate
  • PVDF binder polyvinylidene fluoride
  • NMP N-methylpyrrolidone
  • the prepared first positive electrode slurry and the second positive electrode slurry are simultaneously coated on one surface of an aluminum foil with a thickness of 13 ⁇ m, the first positive electrode active material layer and the second positive electrode active material layer
  • the surface density of the layer is 11.7mg/cm 2 , and it is dried at 120°C.
  • a positive electrode sheet with a compacted density of the positive electrode active material layer of 2.9g/cm 3 is obtained, and then it is formed by lugs, separated Cutting and other processes to obtain a positive electrode sheet with a width of 180mm.
  • the negative electrode slurry is uniformly coated on one surface of a copper foil with a thickness of 8 ⁇ m, the surface density of the negative electrode active material layer is 12.0 mg/cm 2 , dried at 110 ° C, and the compaction of the negative electrode active material layer is obtained after cold pressing Negative pole piece with a density of 1.65g/cm 3 , and then through lug forming, slitting and other processes to obtain a negative pole piece with a width of 183mm.
  • LiFePO 4 lithium iron phosphate
  • PVDF binder polyvinylidene fluoride
  • NMP N-methylpyrrolidone
  • the prepared first positive electrode slurry and the second positive electrode slurry are simultaneously coated on one surface of an aluminum foil with a thickness of 13 ⁇ m, the first positive electrode active material layer and the second positive electrode active material layer
  • the surface density of the layer is 13.0mg/cm 2 , and it is dried at 120°C.
  • a positive electrode sheet with a compacted density of the positive electrode active material layer of 2.4g/cm 3 is obtained, and then the positive electrode sheet is formed by lug forming and separation. Cutting and other processes to obtain a positive electrode sheet with a width of 180mm.
  • the negative electrode slurry is uniformly coated on one surface of a copper foil with a thickness of 8 ⁇ m, the surface density of the negative electrode active material layer is 12.0mg/cm 2 , dried at 110°C, and the compacted density of the negative electrode active material layer is obtained after cold pressing
  • the negative pole piece is 1.65g/cm 3 , and then the negative pole piece with a width of 183mm is obtained through tab forming, cutting and other processes.
  • NMP N-methylpyrrolidone
  • the positive electrode slurry is uniformly coated on one surface of an aluminum foil with a thickness of 13 ⁇ m, the surface density of the positive electrode active material layer is 23.4 mg/cm 2 , dried at 120 ° C, and the compaction of the positive electrode active material layer is obtained after cold pressing
  • the positive pole piece with a density of 2.9g/cm 3 is then processed through lug forming, slitting and other processes to obtain a positive pole piece with a width of 180mm.
  • the positive electrode active material lithium iron phosphate (LiFePO 4 ), the conductive agent conductive carbon black, and the binder polyvinylidene fluoride were mixed in a mass ratio of 97:1:2, and then N-methylpyrrolidone (NMP) was added as a solvent. Stir under the action of a vacuum mixer until the system is uniform, and obtain the first positive electrode slurry with a solid content of 65 wt%.
  • NMP N-methylpyrrolidone
  • NMP N-methylpyrrolidone
  • the prepared first positive electrode slurry and the second positive electrode slurry are simultaneously coated on one surface of an aluminum foil with a thickness of 13 ⁇ m, and the surface density of the first positive electrode active material layer is 25.5mg/ cm 2 , the areal density of the second positive electrode active material layer is 0.71mg/cm 2 , dried at 120°C, and cold pressed to obtain a positive electrode sheet with a compacted density of the positive electrode active material layer of 2.4g/cm 3 , and then through lug forming, slitting and other processes to obtain a positive pole piece with a width of 180mm.
  • the negative electrode slurry is uniformly coated on one surface of a copper foil with a thickness of 8 ⁇ m, the surface density of the negative electrode active material layer is 12.0 mg/cm 2 , dried at 110 ° C, and the compaction of the negative electrode active material layer is obtained after cold pressing Negative pole piece with a density of 1.65g/cm 3 , and then through lug forming, slitting and other processes to obtain a negative pole piece with a width of 183mm.
  • the positive electrode slurry is uniformly coated on one surface of an aluminum foil with a thickness of 13 ⁇ m, the surface density of the positive electrode active material layer is 26 mg/cm 2 , dried at 120 ° C, and the compact density of the positive electrode active material layer obtained after cold pressing is 2.4g/cm 3 of the positive pole piece, and then through the tab forming, cutting and other processes to obtain the positive pole piece with a width of 180mm.
  • the negative electrode active material first graphite, conductive agent conductive carbon black, binder sodium carboxymethyl cellulose (CMC), binder styrene-butadiene rubber (SBR), and polyaniline are in a mass ratio of 94:1:1:2: 2 Mixing, adding deionized water as a solvent, stirring under the action of a vacuum mixer until the system is uniform, and obtaining the first negative electrode slurry with a solid content of 54 wt%.
  • the gram capacity of the first graphite is 348mAh/g
  • the specific surface area BET1 of the first graphite is 0.6m 2 /g.
  • the negative electrode active material second graphite, conductive agent conductive carbon black, binder sodium carboxymethyl cellulose (CMC), binder styrene-butadiene rubber (SBR), and polyaniline are in a mass ratio of 94:1:1:2: 2 Mixing, adding deionized water as a solvent, stirring under the action of a vacuum mixer until the system is uniform, and obtaining a second negative electrode slurry with a solid content of 54 wt%.
  • the gram capacity of the second graphite is 352mAh/g
  • the specific surface area BET2 of the second graphite is 1.4m 2 /g.
  • the prepared first negative electrode slurry and the second negative electrode slurry are simultaneously coated on one surface of a copper foil with a thickness of 8 ⁇ m, the first negative electrode active material layer and the second negative electrode active material layer
  • the average surface density of the material is 6.0mg/cm 2 , dried at 110°C, cold pressed to obtain a negative electrode sheet with a compacted density of the negative electrode active material layer of 1.65g/cm 3 , and then undergoes processes such as tab forming and slitting.
  • a negative electrode sheet with a width of 183 mm was obtained.
  • the negative electrode active material graphite the conductive agent conductive carbon black, the binder sodium carboxymethyl cellulose (CMC), and the binder styrene-butadiene rubber (SBR) in a mass ratio of 96:1:1:2, and add deionized water As a solvent, the mixture was stirred under the action of a vacuum mixer until the system was uniform, and the first negative electrode slurry with a solid content of 54 wt% was obtained.
  • CMC carboxymethyl cellulose
  • SBR styrene-butadiene rubber
  • CMC carboxymethyl cellulose
  • SBR binder styrene-butadiene rubber
  • the prepared first negative electrode slurry and the second negative electrode slurry are simultaneously coated on one surface of a copper foil with a thickness of 8 ⁇ m, and the surface density of the first negative electrode active material layer is 8.1. mg/cm 2 , the areal density of the second positive electrode active material layer is 0.9mg/cm 2 , dried at 110°C, and cold pressed to obtain a positive electrode sheet with a compacted density of 1.68g/cm 3 , and then A positive pole piece with a width of 183 mm was obtained through processes such as tab forming and cutting.
  • the negative electrode slurry is uniformly coated on one surface of a copper foil with a thickness of 8 ⁇ m, the surface density of the negative electrode active material layer is 9.0 mg/cm 2 , dried at 110 ° C, and the compaction of the negative electrode active material layer is obtained after cold pressing Negative pole piece with a density of 1.68g/cm 3 , and then through lug forming, slitting and other processes to obtain a negative pole piece with a width of 183mm.
  • the positive electrode slurry is evenly coated on one surface of an aluminum foil with a thickness of 13 ⁇ m, the surface density of the positive electrode active material layer is 26.0 mg/cm 2 , dried at 120 ° C, and the compaction of the positive electrode active material layer is obtained after cold pressing
  • the positive pole piece with a density of 2.4g/cm 3 is then processed through lug forming, slitting and other processes to obtain a positive pole piece with a width of 180mm.
  • Graphite, conductive agent conductive carbon black, binder sodium carboxymethyl cellulose (CMC), and binder styrene-butadiene rubber (SBR) were mixed according to a mass ratio of 96:1:1:2, and deionized water was added as a solvent. Stir under the action of a vacuum stirrer until the system is uniform to obtain a negative electrode slurry with a solid content of 54 wt%.
  • the negative electrode slurry is uniformly coated on one surface of a copper foil with a thickness of 8 ⁇ m, the surface density of the negative electrode active material layer is 12.0 mg/cm 2 , dried at 110 ° C, and the compaction of the negative electrode active material layer is obtained after cold pressing Negative pole piece with a density of 1.65g/cm 3 , and then through lug forming, slitting and other processes to obtain a negative pole piece with a width of 183mm.
  • the positive electrode active material LiNi 0.5 Co 0.2 Mn 0.3 O 2 , the conductive agent conductive carbon black, and the binder polyvinylidene fluoride (PVDF) were mixed in a mass ratio of 97:1:2, and then N-methylpyrrolidone (NMP) was added as The solvent was stirred under the action of a vacuum mixer until the system was uniform, and a positive electrode slurry with a solid content of 75 wt % was obtained.
  • the positive electrode slurry is uniformly coated on one surface of an aluminum foil with a thickness of 13 ⁇ m, the surface density of the positive electrode active material layer is 21.4 mg/cm 2 , dried at 120 ° C, and the compaction of the positive electrode active material layer is obtained after cold pressing
  • the positive pole piece with a density of 3.4g/cm 3 is then processed through lug forming, slitting and other processes to obtain a positive pole piece with a width of 180mm.
  • Examples 1-13 and Comparative Examples 1-2 The relevant parameters of the positive electrode active material layer and the negative electrode active material layer of the above-mentioned Examples 1-13 and Comparative Examples 1-2 are shown in Table 1 and Table 2 below. Wherein, in Examples 1-9 and Comparative Examples 1-2, the type of positive electrode active material, the type of quinone compound, the type of negative electrode active material and the type of conductive polymer are as shown in Table 1; , The gram capacity and specific surface area of the first graphite, and the gram capacity and specific surface area of the second graphite are shown in Table 2.
  • Table 1 The parameter result of embodiment 1 ⁇ 9 and comparative example 1 ⁇ 2
  • the lithium-ion battery whose positive electrode active material is lithium iron phosphate has a charging cut-off voltage of 3.65V, a discharge cut-off voltage of 2.5V, and an operating voltage of 3.22V, and the lithium-ion battery whose positive electrode active material is LiNi 0.5 Co 0.2 Mn 0.3 O 2
  • the charge cut-off voltage is 4.3V
  • the discharge cut-off voltage is 2.8V
  • the working voltage is 3.68V.
  • the charge cut-off voltage of the lithium-ion battery containing lithium iron phosphate and LiNi 0.5 Co 0.2 Mn 0.3 O 2 as the positive electrode active material is 4.3V.
  • the discharge cut-off voltage is 2.5V, and the working voltage is 3.45V; the thickness of the lithium-ion battery is 39mm, the width of the lithium-ion battery is 160mm, the height of the lithium-ion battery is 203mm, and the volume of the lithium-ion battery is 1.27L.
  • Example 1 152 385
  • Example 2 195 564
  • Example 3 174 471
  • Example 6 154 390
  • Example 7 154 390
  • Example 8 168 425
  • Example 9 169 427
  • Example 10 152 385
  • Example 11 151 383
  • Example 12 154 390
  • Example 13 154.5 391.4
  • the lithium ion batteries of Examples 1 to 13 include a positive electrode sheet and a negative electrode sheet, the positive active material layer of the positive electrode sheet includes a quinone compound, and the negative electrode active material layer of the negative electrode sheet includes a polymer conductive material,
  • the addition ratio of the quinone compound and the conductive polymer is within the scope of the present application, and the lithium-ion battery has better energy density.
  • Example 3 and Example 4 it can be seen from Example 3 and Example 4 that, compared with the lithium ion battery in which the first positive electrode active material layer includes anthraquinone, the lithium ion battery in which the second positive electrode active material layer includes anthraquinone has a higher energy density.
  • the energy density of the lithium ion battery can be improved.
  • the positive electrode active material layer of the positive electrode sheet of Comparative Example 1 does not include quinone compounds, and the negative electrode active material layer of the negative electrode sheet does not include polymer conductive materials, resulting in a volumetric energy density of only 380Wh/ L.
  • the positive electrode active material layer of the positive electrode sheet of Comparative Example 2 does not include quinone compounds, and the negative electrode active material layer of the negative electrode sheet does not include polymer conductive materials, resulting in the volumetric energy density of Comparative Example 2 being only 550Wh/L.
  • 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

本申请提供了一种电极组件、二次电池、电池模块、电池包及用电装置，包括正极极片和负极极片，正极极片的正极活性材料层包括正极活性材料和醌类化合物；负极极片的负极活性材料层包括负极活性材料和高分子导电材料。其中，基于所述正极活性材料层的质量，所述醌类化合物的质量含量mc％为0.5％至3％；所述醌类化合物的克容量为Cap C；所述正极活性材料的克容量为Cap；基于所述负极活性材料层的质量，所述高分子导电材料的质量含量为m A％，符合关系：0.2≤（Capc-Cap）/Cap ×mc/mA≤5。本申请能够提高锂离子电池的能量密度。

Description

一种电极组件、二次电池、电池模块、电池包及用电装置 技术领域
本申请涉及锂电池领域，尤其涉及一种电极组件、二次电池、电池模块、电池包及用电装置。
背景技术
锂离子电池具有循环寿命长、体积小、重量轻、安全性好等优点，广泛应用于便携式电子设备、电能储能和电动汽车等各个领域。
随着便携式电子设备、电能储能和电动汽车的高速发展，人们对锂离子电池的能量密度要求越来越高。因此，亟需进一步提升锂离子电池的能量密度。
发明内容
本申请是鉴于上述课题而进行的，其目的在于提高锂离子电池的能量密度。
为了达到上述目的，本申请提供了一种电极组件、二次电池、电池模块、电池包及用电装置。
本申请的第一方面提供了一种电极组件，其包括正极极片及负极极片；其中，所述正极极片包括正极集流体及设置于所述正极集流体至少一侧表面的正极活性材料层，所述正极活性材料层包括正极活性材料和醌类化合物；所述负极极片包括负极集流体及设置于所述负极集流体至少一侧表面的负极活性材料层，所述负极活性材料层包括负极活性材料和高分子导电材料；其中，基于所述正极活性材料层的质量，所述醌类化合物的质量含量m c％为0.5％至3％；所述醌类化合物的克容量为Cap C；所述正极活性材料的克容量为Cap；基于所述负极活性材料层的质量，所述高分子导电材料的质量含量为m A％，符合以下关系：
Figure PCTCN2021132493-appb-000001
本申请中正极极片的正极活性材料层包括的醌类化合物提供额外的嵌锂空位，提升正极极片的储锂能力；负极活性材料层包括的高分子导电材料用于提高负极极片的动力学性能，提升锂离子电池电池放电时脱出锂的含量。通过协同控制醌类化合物与导电聚合物的添加比例，以提升锂离子电池的能量密度。
在任意实施方式中，所述醌类化合物包括苯醌及其衍生物、萘醌及其衍生物和蒽醌及其衍生物中的至少一种。
在任意实施方式中，所述高分子导电材料包括聚苯胺、聚吡咯、聚噻吩、聚氧化乙烯、聚丙烯腈、聚苯撑和聚乙炔中的至少一种。
在任意实施方式中，所述正极活性材料层的面密度为16.2mg/cm 2至40.0mg/cm 2；所述负极活性材料层的面密度为5.8mg/cm 2至18.0mg/cm 2。
在任意实施方式中，所述正极活性材料层包括沿远离所述正极集流体方向依次层叠的多层正极子活性材料层，其中，所述多层正极子活性材料层中的至少一层包括所述醌类化合物。
在任意实施方式中，所述多层正极子活性材料层远离所述正极集流体的最外层正极子活性材料层包含所述醌类化合物，其余各个正极子活性材料层可以包含或者不包含所述醌类化合物。可选地为，其余各个正极子活性材料层不包含醌类化合物。
在任意实施方式中，所述负极活性材料层包括远离所述负极集流体方向依次层叠的m层负极子活性材料层，靠近所述负极集流体的n层负极子活性材料层中包含所述高分子导电材料，其中，m/3≤n≤m，所述m为大于等于2的正整数，n为大于等于1的正整数。
在任意实施方式中，所述负极活性材料层包含两个负极子活性材料层，靠近所述负极集流体的第一负极子活性材料层包含第一石墨，远离所述负极集流体的第二负极子活性材料层包含第二石墨，所述第二石墨的克容量与所述第一石墨的克容量之差大于等于8mAh/g。
在任意实施方式中，所述负极活性材料层包含两个负极子活性材料层，靠近所述负极集流体的第一负极子活性材料层包含第一石墨，远离所述负极集流体的第二负极子活性材料层包含第二石墨，所述第二石墨的克容量与所述第一石墨的克容量之差小于8mAh/g，第二石墨的比表面积BET2大于第一石墨的比表面积BET1，优选地，BET1为0.2m 2/g～0.8m 2/g，BET2为1m 2/g～2m 2/g。
在任意实施方式中，所述负极活性材料层包含两个负极子活性材料层，靠近所述负极集流体的第一负极子活性材料层包含石墨，远离所述负极集流体的第二负极子活性材料层包含SiO。
在任意实施方式中，所述正极活性材料包括磷酸铁锂、锰酸锂、镍钴锰酸锂、钴酸锂和镍锰尖晶石中的至少一种；所述负极活性材料包括石墨、硬碳、二硫化钼、硅、氧化亚硅、四氧化三铁、氧化锡和二氧化钛中的至少一种。
本申请的第二方面提供一种二次电池，包括本申请第一方面的电极组件。
本申请的第三方面提供一种电池模块，包括本申请的第二方面的二次电池。
本申请的第四方面提供一种电池包，包括本申请的第三方面的电池模块。
本申请的第五方面提供一种用电装置，包括选自本申请的第二方面的二次电池、本申请的第三方面的电池模块或本申请的第四方面的电池包中的至少一种。
本申请的有益效果：本申请提供的一种电极组件、二次电池、电池模块、电池包及用 电装置，正极活性材料层包括的醌类化合物提供额外的嵌锂空位，提升正极极片的储锂能力；负极活性材料层包括的高分子导电材料用于提高负极极片的动力学性能，提升锂离子电池放电时脱出锂的含量。通过协同控制醌类化合物与导电聚合物的添加比例，以提升锂离子电池的能量密度。当然，实施本申请的任一产品或方法并不一定需要同时达到以上所述的所有优点。
附图说明
图1为本申请一实施方式的正极极片的示意图。
图2是本申请一实施方式的二次电池的示意图。
图3是图2所示的本申请一实施方式的二次电池的分解图。
图4是本申请一实施方式的电池模块的示意图。
图5是本申请一实施方式的电池包的示意图。
图6是图5所示的本申请一实施方式的电池包的分解图。
图7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。
附图标记说明：
1负极集流体；2第一负极子活性材料层；3第二负极子活性材料层；4电池模块；5二次电池；51壳体；52电极组件；53顶盖组件；10电池包；11上箱体；12下箱体。
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电极组件、二次电池、电池模块、电池包及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。
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)。
本申请人在研究锂离子电池的过程中发现，锂离子电池存在着能量密度较低的问题，导致锂离子电池难以满足应用需要。为了提高锂离子电池的能量密度，使锂离子电池应用于用电装置时具有更好的性能，例如更长的续航里程，有鉴于此，本申请提供了一种电极组件、二次电池、电池模块、电池包及用电装置。
本申请的一个实施方式中，本申请提出了一种电极组件，包括正极极片及负极极片，其中，正极极片包括正极集流体及设置于正极集流体至少一侧表面的正极活性材料层，正极活性材料层包括正极活性材料和醌类化合物。负极极片包括负极集流体及设置于负极集流体至少一侧表面的负极活性材料层，负极活性材料层包括负极活性材料和高分子导电材料；其中，基于正极活性材料层的质量，醌类化合物的质量含量mc％为0.5％至3％；醌类化合物的克容量为Cap C；正极活性材料的克容量为Cap；基于负极活性材料层的质量，高分子导电材料的质量含量为m A％，符合以下关系：
Figure PCTCN2021132493-appb-000002
不限于任何理论，本申请人经研究发现，正极活性材料层包括的醌类化合物可以提供额外的嵌锂空位，提升正极极片的储锂能力；负极活性材料层包括的高分子导电材料用于 提高负极极片的动力学性能，提升锂离子电池放电时脱出锂的含量。通过协同控制醌类化合物与导电聚合物的添加比例，以提升锂离子电池的能量密度。
在一些实施方式中，醌类化合物包括苯醌及其衍生物、萘醌及其衍生物和蒽醌及其衍生物中的至少一种。
在一些实施方式中，高分子导电材料包括聚苯胺、聚吡咯、聚噻吩、聚氧化乙烯、聚丙烯腈、聚苯撑和聚乙炔中的至少一种。
在一些实施方式中，正极活性材料层的面密度为16.2mg/cm 2至40.0mg/cm 2，例如，正极活性材料层的面密度可以为20.0mg/cm 2、24.0mg/cm 2、28.0mg/cm 2、32.0mg/cm 2、36.0mg/cm 2或为其间的任何范围。不限于任何理论，本申请人发现，当正极活性材料层的面密度过低时，例如低于16.2mg/cm 2，相同容量时极片变长，基材用量增大，不利于能量密度提升；当正极活性材料层的面密度过高时，例如高于40.0mg/cm 2，由于极片加工中厚度压缩需要的时间和力增加，不易压至更高压密，使压密降低，不利于能量密度提升。通过调控正极活性材料层的面密度在上述范围内，可以提高锂离子电池的能量密度。
在一些实施方式中，负极活性材料层的面密度为5.8mg/cm 2至18.0mg/cm 2，例如，负极活性材料层的面密度可以为6.0mg/cm 2、8.0mg/cm 2、10.0mg/cm 2、12.0mg/cm 2、14.0mg/cm 2、16.0mg/cm 2或为其间的任何范围。不限于任何理论，本申请人发现，当负极活性材料层的面密度过低时，例如低于5.8mg/cm 2，相同容量时极片变长，基材用量增大，不利于能量密度提升；当负极活性材料层的面密度过高时，例如高于18.0mg/cm 2，由于极片加工中厚度压缩需要的时间和力增加，不易压至更高压密，使压密降低，不利于能量密度提升。通过调控负极活性材料层的面密度在上述范围内，可以提高锂离子电池的能量密度。
在一些实施方式中，正极活性材料层包括依次层叠的多层正极子活性材料层，其中，多层正极子活性材料层中的至少一层包括醌类化合物。
在一些实施方式中，多层正极子活性材料层远离正极集流体的最外层正极子活性材料层包含醌类化合物，其余各个正极子活性材料层可以包含或者不包含醌类化合物。可选地为，其余各个正极子活性材料层不包含醌类化合物。
本申请人发现，不限于任何理论，通过设置多层正极子活性材料层远离正极集流体的最外层正极子活性材料层包含醌类化合物，即醌类化合物远离正极集流体设置，可以缩短锂离子电池放电时锂离子的迁移路径，降低极化，增强锂离子电池放电时醌类化合物的嵌锂能力，提升锂离子电池的能量密度。
在一些实施方式中，负极活性材料层包括远离负极集流体方向依次层叠的m层负极子活性材料层，靠近负极集流体的n层负极子活性材料层中包含高分子导电材料，其中， m/3≤n≤m，m为大于等于2的正整数，n为大于等于1的正整数。
本申请人发现，不限于任何理论，相对于负极活性材料层中远离负极集流体的负极子活性材料层，负极活性材料层中靠近负极集流体的负极子活性材料层脱锂难度较大。靠近负极集流体设置的n层负极子活性材料层中包含高分子导电材料，即高分子导电材料靠近负极集流体设置，可以提高负极活性材料层中靠近负极集流体的负极子活性材料层的动力学性能，提升负极极片放电时脱出锂的含量，提高锂离子电池的能量密度。
优选地，m层负极子活性材料层可以均包括高分子导电材料。申请人发现，不限于任何理论，通过设置负极子活性材料层均包括高分子导电材料，可以形成贯穿整个负极活性材料层的离子通路，充分提升整个负极极片的动力学性能，提升负极极片放电时脱出锂的含量，从而得到具有良好的能量密度的锂离子电池。
在一些实施方式中，如图1所示，负极活性材料层包含两个负极子活性材料层，包括靠近负极集流体1的第一负极子活性材料层2和远离负极集流体1的第二负极子活性材料层3，靠近负极集流体1的第一负极子活性材料层2包含第一石墨，远离负极集流体1的第二负极子活性材料层3包含第二石墨，第二石墨的克容量与第一石墨的克容量之差大于等于8mAh/g。
本申请人发现，不限于任何理论，通过设置第二石墨的克容量Cap2与所述第一石墨的克容量Cap1之差大于等于8mAh/g，即Cap2-Cap1≥8mAh/g，负极集流体表面的第二石墨能提供更多嵌锂空位，避免由于空位不足导致析锂，以得到高能量密度的锂离子电池。
在一些实施方式中，负极活性材料层包含两个负极子活性材料层，靠近负极集流体的第一负极子活性材料层包含第一石墨，远离负极集流体的第二负极子活性材料层包含第二石墨，第二石墨的克容量Cap2与第一石墨的克容量Cap1之差小于8mAh/g，即Cap2-Cap1＜8mAh/g，第二石墨的比表面积BET2大于第一石墨的比表面积BET1，优选地，BET1为0.2m 2/g～0.8m 2/g，BET2为1m 2/g～2m 2/g。
申请人发现，不限于任何理论，当第二石墨的克容量与第一石墨的克容量之差小于8mAh/g，通过设置第二石墨的比表面积BET2大于等于第一石墨的比表面积BET1，负极集流体表面的第二石墨具备更好的动力学性能，避免阳极表面由于动力学不足析锂，提高锂离子电池的能量密度。
申请人发现，不限于任何理论，所述负极活性材料层包含两个负极子活性材料层，靠近所述负极集流体的第一负极子活性材料层包含石墨，远离所述负极集流体的第二负极子活性材料层包含SiO。其中，石墨的比表面积为0.2m 2/g～2m 2/g，SiO的比表面积为0.5m 2/g～3m 2/g。
在一些实施方式中，正极活性材料包括磷酸铁锂、锰酸锂、镍钴锰酸锂、钴酸锂和镍锰尖晶石中的至少一种。负极活性材料包括石墨、硬碳、二硫化钼、硅、氧化亚硅、四氧化三铁、氧化锡和二氧化钛中的至少一种。
另外，以下适当参照附图对本申请的二次电池、电池模块、电池包和用电装置进行说明。
本申请的一个实施方式中，提供一种二次电池，其包括上述任一实施方式所述的电极组件。本申请的二次电池可以指上述任一实施方式中所述的锂离子电池。
通常情况下，二次电池包括正极极片、负极极片、电解质和隔离膜。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。电解质在正极极片和负极极片之间起到传导离子的作用。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，同时可以使离子通过。
[正极极片]
正极极片包括正极集流体以及设置在正极集流体至少一个表面的正极活性材料层。
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，正极活性材料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，所述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，正极活性材料层可选地包括粘结剂。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。
在一些实施方式中，正极活性材料层还可选地包括导电剂。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。
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。
[负极极片]
负极极片包括负极集流体以及设置在负极集流体至少一个表面上的负极活性材料层，所述负极活性材料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，负极活性材料层设置在负极集流体相对的两个表面中的任意一者或两者上。
在一些实施方式中，所述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，负极活性材料层可选地包括粘结剂。所述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，负极活性材料层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，负极活性材料层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。
在一些实施方式中，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。
[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，所述电解质采用电解液。所述电解液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，所述电解液还可选地包括添加剂。例如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2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3，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4是作为一个示例的电池模块4。参照图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5和图6是作为一个示例的电池包10。参照图5和图6，在电池包10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11和下箱体12，上箱体11能够盖设于下箱体12，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，所述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。所述二次电池、电池模块、或电池包可以用作所述用电装置的电源，也可以用作所述用电装置的能量存储单元。所述用电装置可以包括移动设备(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***等，但不限于此。
作为所述用电装置，可以根据其使用需求来选择二次电池、电池模块或电池包。
图7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。
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。
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
<正极极片的制备>
将正极活性材料磷酸铁锂(LiFePO 4，LFP)、导电剂导电碳黑、粘结剂聚偏氟乙烯(PVDF)、蒽醌按质量比96∶1∶2∶1混合，然后加入N-甲基吡咯烷酮(NMP)作为溶剂，在真空搅拌机作用下搅拌至体系呈均一状，得到固含量为65wt％的正极浆料。将正极浆料均匀涂覆在厚度为13μm的铝箔的一个表面上，正极活性材料层的面密度为26.0mg/cm 2，120℃条件下烘干，冷压后得到正极活性材料层的压实密度为2.4g/cm 3的正极 极片，然后经过极耳成型、分切等工序得到宽度为180mm的正极极片。
<负极极片的制备>
将负极活性材料石墨、导电剂导电炭黑、粘结剂羧甲基纤维素钠(CMC)、粘结剂丁苯橡胶(SBR)、聚苯胺按质量比95∶1∶1∶2∶1混合，加入去离子水作为溶剂，在真空搅拌机作用下搅拌至体系呈均一状，得到固含量为54wt％的负极浆料。将负极浆料均匀涂覆在厚度为8μm的铜箔的一个表面上，负极活性材料层的面密度为12.0mg/cm 2，110℃条件下烘干，冷压后得到负极活性材料层的压实密度为1.65g/cm 3的负极极片，然后经过极耳成型、分切等工序得到宽度为183mm的负极极片。
<电解液的制备>
在含水量小于10ppm的环境下，将非水有机溶剂碳酸乙烯酯、碳酸二甲酯、碳酸甲乙酯按照体积比1∶1∶1进行混合得到质量为450g的电解液溶剂，随后将锂盐LiPF 6溶解于混合后的溶剂中，配置成锂盐浓度为1mol/L的电解液。
<隔离膜的制备>
选择厚度为12μm的聚乙烯作为隔离膜，经分切得到宽度为188mm的隔离膜。
<锂离子电池的制备>
将上述正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正极极片和负极极片之间起到隔离作用，然后卷绕得到电极组件；将电极组件置于外包装壳中，干燥后注入电解液，经过真空封装、静置、化成、整形等工序，得到锂离子电池。
实施例2
<正极极片的制备>
将正极活性材料LiNi 0.5Co 0.2Mn 0.3O 2(NCM523)、导电剂导电碳黑、粘结剂聚偏氟乙烯、蒽醌按质量比95∶1∶2∶2混合，然后加入N-甲基吡咯烷酮作为溶剂，在真空搅拌机作用下搅拌至体系呈均一状，得到固含量为75wt％的正极浆料。将正极浆料均匀涂覆在厚度为13μm的铝箔的一个表面上，正极活性材料层的面密度为21.4mg/cm 2，120℃条件下烘干，冷压后得到正极活性材料层的压实密度为3.4g/cm 3的正极极片，然后经过极耳成型、分切等工序得到宽度为180mm的正极极片。
<负极极片的制备>
将负极活性材料石墨、导电剂导电炭黑、粘结剂羧甲基纤维素钠(CMC)、粘结剂丁苯橡胶、聚噻吩按质量比94.5∶1∶1∶2∶1.5混合，加入去离子水作为溶剂，在真空搅拌机作用下搅拌至体系呈均一状，得到固含量为54wt％的负极浆料。将负极浆料均匀涂覆在厚度为8μm的铜箔的一个表面上，负极活性材料层的面密度为12.0mg/cm 2，110℃条件下 烘干，冷压后得到负极活性材料层的压实密度为1.65g/cm 3的负极极片，然后经过极耳成型、分切等工序得到宽度为183mm的负极极片。
<电解液的制备>、<隔离膜的制备>和<锂离子电池的制备>与实施例1相同。
实施例3
<正极极片的制备>
<第一正极浆料的制备>
将正极活性材料LiNi 0.5Co 0.2Mn 0.3O 2(NCM523)、导电剂导电碳黑、粘结剂聚偏氟乙烯(PVDF)按质量比97∶1∶2混合，然后加入N-甲基吡咯烷酮(NMP)作为溶剂，在真空搅拌机作用下搅拌至体系呈均一状，得到固含量为75wt％的第一正极浆料。
<第二正极浆料的制备>
将正极活性材料磷酸铁锂(LiFePO 4)、导电剂导电碳黑、粘结剂聚偏氟乙烯(PVDF)、蒽醌按质量比95.5∶1∶2∶1.5混合，然后加入N-甲基吡咯烷酮(NMP)作为溶剂，在真空搅拌机作用下搅拌至体系呈均一状，得到固含量为65wt％的第二正极浆料。
<含有第一正极子活性材料层和第二正极子活性材料层的正极极片的制备>
采用双层涂布工艺，将制得的第一正极浆料和第二正极浆料同时涂布在厚度为13μm的铝箔的一个表面上，第一正极子活性材料层和第二正极子活性材料层的面密度均为11.7mg/cm 2，120℃条件下烘干，经冷压后得到正极活性材料层的压实密度为2.9g/cm 3的正极极片，然后经过极耳成型、分切等工序得到宽度为180mm的正极极片。
<负极极片的制备>
将负极活性材料石墨、导电剂导电炭黑、粘结剂羧甲基纤维素钠(CMC)、粘结剂丁苯橡胶(SBR)、聚吡咯按质量比95∶1∶1∶2∶1混合，加入去离子水作为溶剂，在真空搅拌机作用下搅拌至体系呈均一状，得到固含量为54wt％的负极浆料。将负极浆料均匀涂覆在厚度为8μm的铜箔的一个表面上，负极活性材料层的面密度12.0mg/cm 2，110℃条件下烘干，冷压后得到负极活性材料层的压实密度为1.65g/cm 3的负极极片，然后经过极耳成型、分切等工序得到宽度为183mm的负极极片。
<电解液的制备>、<隔离膜的制备>和<锂离子电池的制备>与实施例1相同。
实施例4
<正极极片的制备>
<第一正极浆料的制备>
将正极活性材料磷酸铁锂(LiFePO 4)、导电剂导电碳黑、粘结剂聚偏氟乙烯(PVDF)、蒽醌按质量比95∶1∶2∶2混合，然后加入N-甲基吡咯烷酮(NMP)作为溶剂，在真空搅 拌机作用下搅拌至体系呈均一状，得到固含量为65wt％的第一正极浆料。
<第二正极浆料的制备>
将正极活性材料磷酸铁锂(LiFePO 4)、导电剂导电碳黑、粘结剂聚偏氟乙烯(PVDF)按质量比97∶1∶2混合，然后加入N-甲基吡咯烷酮(NMP)作为溶剂，在真空搅拌机作用下搅拌至体系呈均一状，得到固含量为65wt％的第二正极浆料。
<含有第一正极子活性材料层和第二正极子活性材料层的正极极片的制备>
采用双层涂布工艺，将制得的第一正极浆料和第二正极浆料同时涂布在厚度为13μm的铝箔的一个表面上，第一正极子活性材料层和第二正极子活性材料层的面密度均为13.0mg/cm 2，120℃条件下烘干，经冷压后得到正极活性材料层的压实密度为2.4g/cm 3的正极极片，然后经过极耳成型、分切等工序得到宽度为180mm的正极极片。
<负极极片的制备>
将负极活性材料石墨、导电剂导电炭黑、粘结剂羧甲基纤维素钠(CMC)、粘结剂丁苯橡胶(SBR)、聚苯胺按质量比95∶1∶1∶2∶1混合，加入去离子水作为溶剂，在真空搅拌机作用下搅拌至体系呈均一状，得到固含量为54wt％的负极浆料。将负极浆料均匀涂覆在厚度为8μm的铜箔的一个表面上，负极活性材料层的面密度12.0mg/cm 2，110℃条件下烘干，冷压后得到负极活性材料层压实密度为1.65g/cm 3的负极极片，然后经过极耳成型、分切等工序得到宽度为183mm的负极极片。
<电解液的制备>、<隔离膜的制备>和<锂离子电池的制备>与实施例1相同。
实施例5
<正极极片的制备>
将正极活性材料LiNi 0.5Co 0.2Mn 0.3O 2、正极活性材料磷酸铁锂(LiFePO 4)、导电剂导电碳黑、粘结剂聚偏氟乙烯、萘醌按质量比48∶48∶1∶2∶1混合，然后加入N-甲基吡咯烷酮(NMP)作为溶剂，在真空搅拌机作用下搅拌至体系呈均一状，得到固含量为68wt％的正极浆料。将正极浆料均匀涂覆在厚度为13μm的铝箔的一个表面上，正极活性材料层的面密度为23.4mg/cm 2，120℃条件下烘干，冷压后得到正极活性材料层的压实密度为2.9g/cm 3的正极极片，然后经过极耳成型、分切等工序得到宽度为180mm的正极极片。
<负极极片的制备>、<电解液的制备>、<隔离膜的制备>和<锂离子电池的制备>与实施例3相同。
实施例6
<正极极片的制备>
<第一正极浆料的制备>
将正极活性材料磷酸铁锂(LiFePO 4)、导电剂导电碳黑、粘结剂聚偏氟乙烯按质量比为97∶1∶2混合，然后加入N-甲基吡咯烷酮(NMP)作为溶剂，在真空搅拌机作用下搅拌至体系呈均一状，得到固含量为65wt％的第一正极浆料。
<第二正极浆料的制备>
将苯醌、导电剂导电碳黑、粘结剂聚偏氟乙烯按质量比7∶1∶2混合，然后加入N-甲基吡咯烷酮(NMP)作为溶剂，在真空搅拌机作用下搅拌至体系呈均一状，得到固含量为45wt％的第二正极浆料。
<含有第一正极子活性材料层和第二正极子活性材料层的正极极片的制备>
采用双层涂布工艺，将制得的第一正极浆料和第二正极浆料同时涂布在厚度为13μm的铝箔的一个表面上，第一正极子活性材料层的面密度为25.5mg/cm 2，第二正极子活性材料层的面密度为0.71mg/cm 2，120℃条件下烘干，经冷压后得到正极活性材料层的压实密度为2.4g/cm 3的正极极片，然后经过极耳成型、分切等工序得到宽度为180mm的正极极片。
<负极极片的制备>
将负极活性材料石墨、导电剂导电炭黑、粘结剂羧甲基纤维素钠(CMC)、粘结剂丁苯橡胶(SBR)、聚苯胺按质量比95∶1∶1∶2∶1混合，加入去离子水作为溶剂，在真空搅拌机作用下搅拌至体系呈均一状，得到固含量为54wt％的负极浆料。将负极浆料均匀涂覆在厚度为8μm的铜箔的一个表面上，负极活性材料层的面密度12.0mg/cm 2，110℃条件下烘干，冷压后得到负极活性材料层的压实密度为1.65g/cm 3的负极极片，然后经过极耳成型、分切等工序得到宽度为183mm的负极极片。
<电解液的制备>、<隔离膜的制备>和<锂离子电池的制备>与实施例1相同。
实施例7
<正极极片的制备>
将正极活性材料磷酸铁锂、导电剂导电炭黑、粘结剂聚偏氟乙烯、苯醌按质量比为95：1∶2∶2混合，然后加入N-甲基吡咯烷酮(NMP)作为溶剂，在真空搅拌机作用下搅拌至体系呈均一状，得到固含量为65wt％的正极浆料。将正极浆料均匀涂覆在厚度为13μm的铝箔的一个表面上，正极活性材料层的面密度为26mg/cm 2，120℃条件下烘干，冷压后得到正极活性材料层压实密度为2.4g/cm 3的正极极片，然后经过极耳成型、分切等工序得到宽度为180mm的正极极片。
<负极极片的制备>
<第一负极浆料的制备>
将负极活性材料第一石墨、导电剂导电炭黑、粘结剂羧甲基纤维素钠(CMC)、粘结剂丁苯橡胶(SBR)、聚苯胺按质量比94∶1∶1∶2∶2混合，加入去离子水作为溶剂，在真空搅拌机作用下搅拌至体系呈均一状，得到固含量为54wt％的第一负极浆料。其中，第一石墨的克容量为348mAh/g，第一石墨的比表面积BET1为0.6m 2/g。
<第二负极浆料的制备>
将负极活性材料第二石墨、导电剂导电炭黑、粘结剂羧甲基纤维素钠(CMC)、粘结剂丁苯橡胶(SBR)、聚苯胺按质量比94∶1∶1∶2∶2混合，加入去离子水作为溶剂，在真空搅拌机作用下搅拌至体系呈均一状，得到固含量为54wt％的第二负极浆料。其中，第二石墨的克容量为352mAh/g，第二石墨的比表面积BET2为1.4m 2/g。
<含有第一负极子活性材料层和第二负极子活性材料层的负极极片的制备>
采用双层涂布工艺，将制得的第一负极浆料和第二负极浆料同时涂布在厚度为8μm的铜箔的一个表面上，第一负极活性材料层和第二负极活性材料层的面密度均6.0mg/cm 2，110℃条件下烘干，冷压后得到负极活性材料层的压实密度为1.65g/cm 3的负极极片，然后经过极耳成型、分切等工序得到宽度为183mm的负极极片。
<电解液的制备>、<隔离膜的制备>和<锂离子电池的制备>与实施例1相同。
实施例8
<负极极片的制备>
<第一负极浆料的制备>
将负极活性材料石墨、导电剂导电炭黑、粘结剂羧甲基纤维素钠(CMC)、粘结剂丁苯橡胶(SBR)按质量比96∶1∶1∶2混合，加入去离子水作为溶剂，在真空搅拌机作用下搅拌至体系呈均一状，得到固含量为54wt％的第一负极浆料。
<第二负极浆料的制备>
将负极活性材料氧化亚硅、导电剂导电炭黑、粘结剂羧甲基纤维素钠(CMC)、粘结剂丁苯橡胶(SBR)、聚苯胺按质量比94∶1∶1∶2∶2混合，加入去离子水作为溶剂，在真空搅拌机作用下搅拌至体系呈均一状，得到固含量为54wt％的第一负极浆料。
<含有第一负极子活性材料层和第二负极子活性材料层的负极极片的制备>
采用双层涂布工艺，将制得的第一负极浆料和第二负极浆料同时涂布在厚度为8μm的铜箔的一个表面上，第一负极子活性材料层的面密度均为8.1mg/cm 2，第二正极子活性材料层的面密度均为0.9mg/cm 2，110℃条件下烘干，经冷压后得到压实密度为1.68g/cm 3的正极极片，然后经过极耳成型、分切等工序得到宽度为183mm的正极极片。
<正极极片的制备>、<电解液的制备>、<隔离膜的制备>和<锂离子电池的制备>与实 施例7相同。
实施例9
<负极极片的制备>
将负极活性材料石墨、负极活性材料氧化亚硅、导电剂导电炭黑、粘结剂羧甲基纤维素钠、粘结剂丁苯橡胶、聚苯胺按质量比85∶9.5∶1∶1∶2∶1.5混合，加入去离子水作为溶剂，在真空搅拌机作用下搅拌至体系呈均一状，得到固含量为54wt％的负极浆料。将负极浆料均匀涂覆在厚度为8μm的铜箔的一个表面上，负极活性材料层的面密度9.0mg/cm 2，110℃条件下烘干，冷压后得到负极活性材料层的压实密度为1.68g/cm 3的负极极片，然后经过极耳成型、分切等工序得到宽度为183mm的负极极片。
<正极极片的制备>、<电解液的制备>、<隔离膜的制备>和<锂离子电池的制备>与实施例7相同。
实施例10至实施例13
除了在<负极极片的制备>中，如表2所示调整第一石墨和第二石墨的克容量和比表面积以外，其余与实施例7相同。
对比例1
<正极极片的制备>
将正极活性材料磷酸铁锂(LiFePO 4)、导电剂导电碳黑、粘结剂聚偏氟乙烯(PVDF)按质量比97∶1∶2混合，然后加入N-甲基吡咯烷酮(NMP)作为溶剂，在真空搅拌机作用下搅拌至体系呈均一状，得到固含量为65wt％的正极浆料。将正极浆料均匀涂覆在厚度为13μm的铝箔的一个表面上，正极活性材料层的面密度为26.0mg/cm 2，120℃条件下烘干，冷压后得到正极活性材料层的压实密度为2.4g/cm 3的正极极片，然后经过极耳成型、分切等工序得到宽度为180mm的正极极片。
<负极极片的制备>
将石墨、导电剂导电炭黑、粘结剂羧甲基纤维素钠(CMC)、粘结剂丁苯橡胶(SBR)按照质量比96∶1∶1∶2混合，加入去离子水作为溶剂，在真空搅拌机作用下搅拌至体系呈均一状，得到固含量为54wt％的负极浆料。将负极浆料均匀涂覆在厚度为8μm的铜箔的一个表面上，负极活性材料层的面密度12.0mg/cm 2，110℃条件下烘干，冷压后得到负极活性材料层的压实密度为1.65g/cm 3的负极极片，然后经过极耳成型、分切等工序得到宽度为183mm的负极极片。
<电解液的制备>、<隔离膜的制备>和<锂离子电池的制备>与实施例1相同。
对比例2
<正极极片的制备>
将正极活性材料LiNi 0.5Co 0.2Mn 0.3O 2、导电剂导电碳黑、粘结剂聚偏氟乙烯(PVDF)按质量比97∶1∶2混合，然后加入N-甲基吡咯烷酮(NMP)作为溶剂，在真空搅拌机作用下搅拌至体系呈均一状，得到固含量为75wt％的正极浆料。将正极浆料均匀涂覆在厚度为13μm的铝箔的一个表面上，正极活性材料层的面密度为21.4mg/cm 2，120℃条件下烘干，冷压后得到正极活性材料层的压实密度为3.4g/cm 3的正极极片，然后经过极耳成型、分切等工序得到宽度为180mm的正极极片。
<电解液的制备>、<正极极片的制备>、<隔离膜的制备>和<锂离子电池的制备>与对比例1相同。
上述实施例1～13、对比例1～2的正极活性材料层和负极活性材料层的相关参数如下述表1和表2所示。其中，实施例1～9与对比例1～2中，正极活性材料的种类、醌类化合物的种类、负极活性材料的种类与导电聚合物的种类如表1所示；实施例10～13中，第一石墨的克容量和比表面积、第二石墨的克容量和比表面积如表2所示。
表1：实施例1～9与对比例1～2的参数结果
Figure PCTCN2021132493-appb-000003
表2：实施例10～13的相关参数
Figure PCTCN2021132493-appb-000004
另外，将上述实施例1～13和对比例1～2中制得的锂离子电池，进行性能测试。测试结果如下表3所示。
能量密度测试：
使用充放电设备，按照1/3C电流充电到充电截至电压(C是标称容量)，在截至电压恒压充电至电流降低到0.05C，使用1/3C电流放电到放电截至电压，使用放电过程测试的容量，然后根据以下公式计算能量密度：能量密度(Wh/L)＝放电容量(Ah)×工作电压(V)/电池体积(L)，锂离子电池的体积(L)＝锂离子电池的厚度×锂离子电池的宽度×锂离子电池的高度。其中，正极活性材料为磷酸铁锂的锂离子电池的充电截至电压为3.65V，放电截至电压为2.5V，工作电压为3.22V，正极活性材料为LiNi 0.5Co 0.2Mn 0.3O 2的锂离子电池的充电截至电压为4.3V，放电截至电压为2.8V，工作电压为3.68V，正极活性材料包含有磷酸铁锂和LiNi 0.5Co 0.2Mn 0.3O 2的锂离子电池的充电截至电压为4.3V，放电截至电压为2.5V，工作电压为3.45V；锂离子电池的厚度为39mm，锂离子电池的宽度为160mm，锂离子电池的高度为203mm，锂离子电池的体积为1.27L。
表3：实施例1～13与对比例1～2的性能测试结果
名称 放电容量(Ah) 能量密度(Wh/L)
实施例1 152 385
实施例2 195 564
实施例3 174 471
实施例4 151 382
实施例5 173 467
实施例6 154 390
实施例7 154 390
实施例8 168 425
实施例9 169 427
实施例10 152 385
实施例11 151 383
实施例12 154 390
实施例13 154.5 391.4
对比例1 150 380
对比例2 190 550
根据上述结果可知，实施例1～13的锂离子电池包括正极极片和负极极片，正极极片的正极活性材料层包括醌类化合物，负极极片的负极活性材料层包括高分子导电材料，醌类化合物与导电聚合物的添加比例在本申请范围之内，锂离子电池具有较佳的能量密度。
从实施例3和实施例4可以看出，相对于第一正极子活性材料层包括蒽醌的锂离子电池，第二正极子活性材料层包括蒽醌的锂离子电池具有更高的能量密度。换言之，蒽醌位于正极活性材料层中远离正极集流体的正极子活性材料层时，可以提高锂离子电池的能量密度。
而相对于此，对比例1的正极极片的正极活性材料层不包括醌类化合物，负极极片的负极活性材料层不包括高分子导电材料，导致对比例1的体积能量密度仅有380Wh/L。
对比例2的正极极片的正极活性材料层不包括醌类化合物，负极极片的负极活性材料层不包括高分子导电材料，导致对比例2的体积能量密度仅有550Wh/L。
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。
以上所述仅为本发明的较佳实施例，并不用以限制本发明，凡在本发明的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本发明保护的范围之内。

Claims (15)

  1. 一种电极组件，其包括正极极片及负极极片；
    其中，所述正极极片包括正极集流体及设置于所述正极集流体至少一侧表面的正极活性材料层，所述正极活性材料层包括正极活性材料和醌类化合物；
    所述负极极片包括负极集流体及设置于所述负极集流体至少一侧表面的负极活性材料层，所述负极活性材料层包括负极活性材料和高分子导电材料；
    其中，基于所述正极活性材料层的质量，所述醌类化合物的质量含量m c％为0.5％至3％；所述醌类化合物的克容量为Cap C；所述正极活性材料的克容量为Cap；
    基于所述负极活性材料层的质量，所述高分子导电材料的质量含量为m A％，符合以下关系：
    Figure PCTCN2021132493-appb-100001
  2. 根据权利要求1所述的电极组件，其中，所述醌类化合物包括苯醌及其衍生物、萘醌及其衍生物和蒽醌及其衍生物中的至少一种。
  3. 根据权利要求1或2所述的电极组件，其中，所述高分子导电材料包括聚苯胺、聚吡咯、聚噻吩、聚氧化乙烯、聚丙烯腈、聚苯撑和聚乙炔中的至少一种。
  4. 根据权利要求1至3任一项所述的电极组件，其中，
    所述正极活性材料层的面密度为16.2mg/cm 2至40.0mg/cm 2；
    所述负极活性材料层的面密度为5.8mg/cm 2至18.0mg/cm 2。
  5. 根据权利要求1至4任一项所述的电极组件，其中，所述正极活性材料层包括沿远离所述正极集流体方向依次层叠的多层正极子活性材料层，其中，所述多层正极子活性材料层中的至少一层包括所述醌类化合物。
  6. 根据权利要求5所述的电极组件，其中，所述多层正极子活性材料层远离所述正极集流体的最外层正极子活性材料层包含所述醌类化合物，其余各个正极子活性材料层可以包含或者不包含所述醌类化合物。
  7. 根据权利要求1-6任一项所述的电极组件，其中，所述负极活性材料层包括远离所述负极集流体方向依次层叠的m层负极子活性材料层，靠近所述负极集流体的n层负极子活性材料层中包含所述高分子导电材料，其中，m/3≤n≤m，所述m为大于等于2的正整数，n为大于等于1的正整数。
  8. 根据权利要求1-6任一项所述的电极组件，其中，所述负极活性材料层包含两个负极子活性材料层，靠近所述负极集流体的第一负极子活性材料层包含第一石墨，远离所述负 极集流体的第二负极子活性材料层包含第二石墨，所述第二石墨的克容量与所述第一石墨的克容量之差大于等于8mAh/g。
  9. 根据权利要求1-6任一项所述的电极组件，其中，所述负极活性材料层包含两个负极子活性材料层，靠近所述负极集流体的第一负极子活性材料层包含第一石墨，远离所述负极集流体的第二负极子活性材料层包含第二石墨，所述第二石墨的克容量与所述第一石墨的克容量之差小于8mAh/g，第二石墨的比表面积BET2大于第一石墨的比表面积BET1，优选地，BET1为0.2m 2/g～0.8m 2/g，BET2为1m 2/g～2m 2/g。
  10. 根据权利要求1-6任一项所述的电极组件，其中，所述负极活性材料层包含两个负极子活性材料层，靠近所述负极集流体的第一负极子活性材料层包含石墨，远离所述负极集流体的第二负极子活性材料层包含SiO。
  11. 根据权利要求1至10任一所述的电极组件，其中，所述正极活性材料包括磷酸铁锂、锰酸锂、镍钴锰酸锂、钴酸锂和镍锰尖晶石中的至少一种；
    所述负极活性材料包括石墨、硬碳、二硫化钼、硅、氧化亚硅、四氧化三铁、氧化锡和二氧化钛中的至少一种。
  12. 一种二次电池，其包括权利要求1至11中任一项所述的电极组件。
  13. 一种电池模块，其包括权利要求12所述的二次电池。
  14. 一种电池包，其包括权利要求13所述的电池模块。
  15. 一种用电装置，其包括选自权利要求12所述的二次电池、权利要求13所述的电池模块或权利要求14所述的电池包中的至少一种。
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