WO2024207353A1 - 正极极片及其制备方法、电池单体、电池和用电装置 - Google Patents

正极极片及其制备方法、电池单体、电池和用电装置 Download PDF

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Publication number
WO2024207353A1
WO2024207353A1 PCT/CN2023/086699 CN2023086699W WO2024207353A1 WO 2024207353 A1 WO2024207353 A1 WO 2024207353A1 CN 2023086699 W CN2023086699 W CN 2023086699W WO 2024207353 A1 WO2024207353 A1 WO 2024207353A1
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WIPO (PCT)
Prior art keywords
positive electrode
active material
electrode sheet
coating
coating layer
Prior art date
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PCT/CN2023/086699
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English (en)
French (fr)
Inventor
赵丰刚
赵子萌
金海族
史松君
来佑磊
喻鸿钢
徐熙烨
李静如
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Contemporary Amperex Technology Co Ltd
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Contemporary Amperex Technology Co Ltd
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Priority to PCT/CN2023/086699 priority Critical patent/WO2024207353A1/zh
Priority to EP23931421.4A priority patent/EP4664550A4/en
Priority to CN202380063729.0A priority patent/CN119790507A/zh
Publication of WO2024207353A1 publication Critical patent/WO2024207353A1/zh
Priority to US19/309,168 priority patent/US20250379220A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—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
    • 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
    • H01M4/04—Processes of manufacture in general
    • H01M4/0402—Methods of deposition of the material
    • H01M4/0404—Methods of deposition of the material by coating on electrode collectors
    • 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
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
    • 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
    • H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • 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
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • 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
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • 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
    • H01M4/623—Binders being polymers fluorinated polymers
    • 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
    • H01M4/625—Carbon or graphite
    • 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
    • H01M2004/028—Positive electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • lithium-ion batteries are widely used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace and other fields.
  • the performance of the positive electrode sheet is crucial to the performance of the battery. Therefore, how to provide a positive electrode sheet to improve the performance of the battery is a technical problem that needs to be solved urgently.
  • the embodiments of the present application provide a positive electrode plate and a preparation method thereof, a battery cell, a battery and an electrical device to improve the performance of the battery.
  • a positive electrode plate comprising: a positive electrode collector; a first coating, the first coating being arranged on the surface of at least one side of the positive electrode collector, the first coating comprising a first active material; a second coating, the second coating comprising a second active material, the second active material being different from the first active material; and a conductive layer, the conductive layer being arranged between the first coating and the second coating, and being used to isolate the first coating and the second coating.
  • the embodiment of the present application provides a positive electrode plate, including a positive electrode current collector, a first coating, a second coating and a conductive layer.
  • the first coating is disposed on the surface of at least one side of the positive electrode current collector, and the conductive layer is disposed between the first coating and the second coating.
  • the first active material included in the first coating and the second active material included in the second coating are different, that is, the positive electrode active material includes two different materials, the first active material and the second active material.
  • the positive electrode active material provided by the positive electrode plate can have both the first active material and the second active material. The advantages of the first active material and the second active material are thus beneficial to improving the overall performance of the battery.
  • the first coating and the second coating are separated by a conductive layer to avoid direct contact between the first active material and the second active material, while electrically connecting the first active material and the second active material.
  • the provision of the conductive layer not only avoids direct contact between the first active material and the second active material, but also ensures electrical connection between the first active material and the second active material, so that the first active material and the second active material can play their respective advantages, so that the overall performance of the battery is improved.
  • the first active material includes at least one of an olivine structure phosphate material and a spinel material.
  • Olivine structure is a crystal structure of materials. Materials with olivine structure have high stability. When applied to battery cells, they can reduce the risk of fire and explosion of battery cells under high temperature and other conditions, which is beneficial to improving the reliability of battery cells. Olivine structure phosphates have the advantages of high theoretical specific capacity, good cycle stability, low cost and environmental friendliness. Spinel is a mineral composed of magnesium aluminum oxide, with tetrahedral and octahedral crystal forms. For example, spinel-type lithium manganese oxide materials have outstanding characteristics such as high specific capacity, low cost and low environmental pollution. Olivine structure phosphate materials and spinel materials are used as the first active material, which is beneficial to improving the performance of the battery.
  • the olivine structure phosphate material includes Li a Fe b M 1-b P 1- m O 4-n , wherein M includes at least one of other metal elements except Fe, wherein 0 ⁇ a ⁇ 1.1, 0.3 ⁇ b ⁇ 1, 0 ⁇ m ⁇ 0.1, 0 ⁇ n ⁇ 0.1, optionally, M includes at least one of Mn, Al, Cu, Mg, Zn, Ni, Ti, V, Zr, Co, Ga, Sn, Sb, Nb and Ge, optionally, the olivine structure phosphate material includes at least one of lithium iron phosphate (LiFePO 4 ) and lithium manganese iron phosphate (LiMnFePO 4 ).
  • LiFePO 4 lithium iron phosphate
  • LiMnFePO 4 lithium manganese iron phosphate
  • Lithium iron phosphate has the advantages of long cycle life, good thermal stability, and high energy density; lithium iron manganese phosphate also has the advantages of long cycle life and good thermal stability. Lithium iron phosphate and lithium iron manganese phosphate are used as the first active material to improve the cycle performance, energy density and safety of the battery.
  • the spinel material includes LiNi c Mn 2-c O 4 , wherein 0 ⁇ c ⁇ 2.
  • the spinel material includes lithium manganese oxide (LiMn 2 O 4 ).
  • Lithium manganate is used as positive electrode active material with low price, high potential, environmental friendliness, high safety performance, Good rate performance and other advantages.
  • the second active material includes a layered transition metal oxide.
  • Layered transition metal oxides as active materials for the positive electrode of batteries are a class of oxides with a multilayer (generally two-dimensional) structure, which are obtained based on the redox reaction of transition metal cations and lattice oxygen anions, and have high energy and high power density. Layered transition metal oxides can be used as the second active material to increase the energy density of the battery.
  • the layered transition metal oxide includes at least one of LiCoO 2 , LiMnO 2 , LiNiO 2 , Li a' Ni x Co y M 1 1-xy O 2+d , and zLi 2 MnO 3 ⁇ (1-z)LiM 2 O 2 , wherein M 1 includes at least one of Mn, Zr, Al, B, Ta, Mo, W, Nb, Sb, and La, and M 2 includes at least one of Co, Ni, and Mn, 0.5 ⁇ x ⁇ 1.0, 0 ⁇ y ⁇ 0.5, x+y ⁇ 1, 0.2 ⁇ a' ⁇ 1.2, -0.02 ⁇ d ⁇ 0.02, and 0 ⁇ z ⁇ 1.
  • the layered transition metal oxide includes Li(Ni 0.6 Co 0.2 Mn 0.2 ) 1.15 O 2 , Li(Ni 0.5 Co 0.2 Mn 0.3 ) 1.07 At least one of O 2 .
  • Lithium nickel cobalt manganese oxide (NCM) used as positive electrode active material has the advantages of high energy density, high voltage platform, good thermal stability and good cycle performance.
  • the conductive layer includes a conductive agent and a binder.
  • Conductive agents collect microcurrents between active materials to reduce the contact resistance of the electrode and accelerate the movement of electrons. They can also effectively increase the migration rate of metal ions in the electrode material, thereby improving the charge and discharge efficiency of the electrode. Binders can bond the active material to the conductive agent, enhance the electrical contact between the active material and the conductive agent, and stabilize the structure of the positive electrode.
  • the conductive agent includes at least one of conductive carbon black, superconducting carbon, carbon dots, Ketjen black and carbon nanotubes.
  • the binder includes polyvinylidene fluoride, styrene butadiene rubber, At least one of polytetrafluoroethylene, vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-trichloroethylene copolymer and fluorine-containing acrylic resin, polyacrylonitrile, polyvinyl pyrrolidone, polyvinyl acetate, polyethylene-co-vinyl acetate, polyethylene oxide, and polyarylate.
  • the thickness of the conductive layer is 1 ⁇ m to 15 ⁇ m, and optionally, the thickness of the conductive layer is 5 ⁇ m to 10 ⁇ m.
  • the thickness of the conductive layer should not be too small, so that the conductive layer can effectively isolate the first active material from the second active material.
  • the thickness of the conductive layer should not be too large, so that the content of active material in the positive electrode sheet is not too small, so as to ensure the energy density of the battery.
  • the thickness of the second coating is 40 ⁇ m to 80 ⁇ m, and optionally, the thickness of the second coating is 40 ⁇ m to 60 ⁇ m.
  • the thickness of the second coating should not be too large to reduce the waste of the second active material and the total volume of the battery, thereby reducing the production cost.
  • the thickness of the second coating should not be too small to ensure that the content of the second active material in the positive electrode sheet is not too small, which is conducive to improving the battery performance.
  • the weight percentage of the binder in the conductive layer is 1 wt% to 10 wt%, and optionally, 3 wt% to 7 wt%.
  • the conductive agent in the conductive layer collects microcurrents between active materials to reduce the contact resistance of the electrode and accelerate the movement rate of electrons. It can also effectively increase the migration rate of metal ions in the electrode material, thereby improving the charge and discharge efficiency of the electrode. If the content of the conductive agent is too little, it will reduce the electron conduction channel in the positive electrode sheet, resulting in low utilization of the positive active material, thereby reducing the cycle performance and energy density of the battery.
  • the conductive layer can effectively play its role of isolating and electrically connecting the first active material and the second active material to improve the overall performance of the battery.
  • the weight percentage of the conductive agent in the first coating layer is 0.1 wt% to 1 wt%, and optionally, 0.4 wt% to 0.6 wt%.
  • the weight percentage of the binder in the first coating layer is 1 wt% to 2 wt%, and optionally, 1.2 wt% to 1.4 wt%.
  • the weight contents of the first active material, the conductive agent and the binder in the first coating layer are set within an appropriate range, so that the first active material can effectively play its role.
  • the weight percentage of the second active material is 90 wt % to 98 wt %, and optionally, 96 wt % to 97 wt %.
  • the weight percentage of the conductive agent in the second coating layer is 0.1 wt% to 1 wt%, and optionally, 0.4 wt% to 0.6 wt%.
  • the weight percentage of the binder in the second coating layer is 1 wt% to 2 wt%, and optionally, 1.2 wt% to 1.4 wt%.
  • the weight contents of the second active material, the conductive agent and the binder in the second coating layer are set within an appropriate range, so that the second active material can effectively function.
  • a method for preparing a positive electrode plate comprising: providing a positive electrode current collector, and arranging a first coating, a second coating and a conductive layer on the positive electrode current collector; wherein the first coating is arranged on the surface of at least one side of the positive electrode current collector, the conductive layer is arranged between the first coating and the second coating, the first coating includes a first active material, the second coating includes a second active material, and the second active material is different from the first active material.
  • a battery cell comprising the positive electrode plate in the first aspect and any possible implementation thereof.
  • a battery comprising the battery cell described in the third aspect.
  • an electrical device comprising the battery described in the fourth aspect.
  • the present application provides a positive electrode sheet, including a positive electrode current collector, a first coating, a second coating, and a conductive layer.
  • the first coating is disposed on at least one side of the positive electrode current collector, and the conductive layer is disposed on Between the first coating and the second coating.
  • the first active material included in the first coating is different from the second active material included in the second coating, that is, the positive electrode active material includes two different materials, the first active material and the second active material.
  • the positive electrode active material provided by the positive electrode plate can have the advantages of the first active material and the second active material, which is beneficial to improve the overall performance of the battery.
  • the first coating and the second coating are separated by a conductive layer to avoid direct contact between the first active material and the second active material, and at the same time electrically connect the first active material and the second active material.
  • the setting of the conductive layer not only avoids direct contact between the first active material and the second active material, but also ensures the electrical connection between the first active material and the second active material, so that the first active material and the second active material can play their respective advantages, so that the overall performance of the battery is improved.
  • FIG1 is a schematic diagram of a positive electrode sheet according to an embodiment of the present application.
  • FIG2 is a schematic diagram of a positive electrode sheet according to an embodiment of the present application.
  • FIG3 is a schematic diagram of a method for preparing a positive electrode sheet according to an embodiment of the present application.
  • FIG4 is a schematic diagram of a battery cell disclosed in an embodiment of the present application.
  • FIG5 is a schematic diagram of an exploded structure of a battery cell disclosed in an embodiment of the present application.
  • FIG6 is a schematic diagram of an exploded structure of a battery disclosed in an embodiment of the present application.
  • FIG. 7 is a schematic diagram of an electrical device disclosed in an embodiment of the present application.
  • Positive electrode sheet 1 positive electrode current collector 10, first coating 11, second coating 12, conductive layer 13, battery 10, box 11, battery cell 20, shell 21, electrode assembly 22, cover plate 23.
  • “Scope” disclosed in the present application is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range.
  • the scope limited in this way can be including end values or not including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected.
  • the numerical range "a-b" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers.
  • the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations.
  • a parameter is expressed as an integer ⁇ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.
  • the steps are performed sequentially.
  • the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially.
  • the method may also include step (c), which means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.
  • the term "or” is inclusive.
  • the phrase “A or B” means “A, B, or both A and B”. More specifically, any of the following conditions satisfies the condition "A or B”: 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 positive electrode sheet includes a positive current collector and a positive active material coated on the surface of the positive current collector.
  • the positive active material is an important factor affecting battery performance. In order to improve the overall performance of the battery, such as making the battery have both good cycle performance and high energy density, two or more positive active materials will be coated on the surface of the positive current collector. However, the electrochemical properties of different active materials are different. For example, different electronic conductivity will lead to poor contact between different active materials, affecting the overall conductivity of the positive active material, thereby affecting the performance of the battery.
  • the embodiment of the present application provides a positive electrode plate, including a positive electrode current collector, a first coating, a second coating and a conductive layer.
  • the first coating is disposed on the surface of at least one side of the positive electrode current collector, and the conductive layer is disposed between the first coating and the second coating.
  • the first active material included in the first coating is different from the second active material included in the second coating, that is, the positive electrode active material includes two different materials, the first active material and the second active material. In this way, the positive electrode active material provided by the positive electrode plate can have both the first active material and the second active material.
  • FIG1 is a schematic diagram of a positive electrode sheet according to an embodiment of the present application.
  • the positive electrode sheet 1 includes a positive electrode current collector 10 , a first coating 11 , a second coating 12 and a conductive layer 13 .
  • the conductive layer 13 is disposed between the first coating layer 11 and the second coating layer 12, and the first coating layer is disposed on the surface of the positive electrode current collector 10.
  • the positive electrode current collector 10 along the thickness direction of the positive electrode sheet 1 (the z direction in FIG1 ), the positive electrode current collector 10, the first coating layer 11, the conductive layer 13, and the second coating layer 12 are disposed in sequence.
  • the positive electrode current collector 10 has two surfaces arranged along its thickness direction, and the first coating layer 11, the conductive layer 13 and the second coating layer 12 are arranged on the surface of the same side of the positive electrode current collector 10.
  • the first coating layer 11, the conductive layer 13 and the second coating layer 12 are arranged on both surfaces of the positive electrode current collector 10.
  • Fig. 2 is a schematic diagram of a positive electrode sheet according to an embodiment of the present application.
  • one of two surfaces of the positive electrode current collector 10 that are opposite to each other in the thickness direction is provided with a first coating layer 11 , a conductive layer 13 , and a second coating layer 12 .
  • the first coating layer 11 includes a first active material
  • the second coating layer 12 includes a second active material, which is different from the first active material
  • the first active material and the second active material have different crystal structures, wherein the crystal structure may represent the spatial arrangement of atoms in the material.
  • the first active material includes a phosphate material having an olivine structure and a material having a spinel structure
  • the second active material includes a transition metal oxide having a layered structure.
  • the material having an olivine structure may include a variety of materials, such as lithium iron phosphate (LiFePO 4 ) and lithium manganese iron phosphate (LiMnFePO 4 ).
  • the transition metal oxide having a layered structure may include a variety of materials, such as LiMO 2 , where M includes at least one of Co, Ni, and Mn.
  • the conductive layer 13 is used to separate the first active material from the second active material.
  • the risk of the first active material contacting the second active material can be reduced, thereby reducing the risk of the first active material contacting the second active material.
  • the difference in performance of the two active materials affects the battery cell.
  • the conductive layer 13 can realize the electrical connection between the first active material and the second active material.
  • the first active material is lithium iron phosphate with a carbon coating layer
  • the second active material is a ternary material.
  • the first active material attaching to or coating the surface of the second active material may cause electrons to gather on the surface of the second active material, and the gathered electrons affect the embedding of lithium ions into the second active material, thereby affecting the cycle performance of the battery cell.
  • the conductive layer 13 isolates the first active material and the second active material, which can reduce the risk of the first active material attaching to or coating the second active material, and improve the aggregation phenomenon of electrons on the surface of the second active material caused by the difference in conductivity between the first active material and the second active material, thereby helping to reduce the risk of the gathered electrons embedding lithium ions into the second active material, and helping to improve the cycle performance of the battery cell.
  • the cycle performance of a battery cell can be measured by the capacity retention rate, which is the ratio of the retained capacity to the first discharge capacity.
  • the retained capacity can refer to the discharge capacity of the battery cell after a certain number of charge and discharge cycles.
  • the first discharge capacity can refer to the discharge capacity of the battery cell when the battery cell is subjected to the first charge and discharge test.
  • the positive electrode current collector 10 may be a metal foil or a composite current collector.
  • the metal foil aluminum foil may be used.
  • 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 may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PET polyethylene terephthalate
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the embodiment of the present application provides a positive electrode plate 1, including a positive electrode current collector 10, a first coating 11, a second coating 12 and a conductive layer 13.
  • the first active material included in the first coating 11 is different from the second active material included in the second coating 12, that is, the positive electrode active material includes two different materials, the first active material and the second active material.
  • the positive electrode active material provided by the positive electrode plate 1 can have the advantages of the first active material and the second active material, which is conducive to improving the overall performance of the battery.
  • the first coating 11 and the second coating 12 are separated by the conductive layer 13 to avoid direct contact between the first active material and the second active material, and at the same time electrically connect the first active material and the second active material.
  • the provision of the conductive layer 13 not only avoids direct contact between the first active material and the second active material, but also ensures the electrical connection between the first active material and the second active material, so that the first active material and the second active material can play their respective advantages, so that the overall performance of the battery is improved.
  • the first active material includes an olivine structure phosphate material, a sharp At least one of the crystal materials.
  • Olivine structure is a crystal structure of materials. Materials with olivine structure have high stability. When applied to battery cells, they can reduce the risk of fire and explosion of battery cells under high temperature and other conditions, which is beneficial to improving the reliability of battery cells. Olivine structure phosphates have the advantages of high theoretical specific capacity, good cycle stability, low cost and environmental friendliness. Spinel is a mineral composed of magnesium aluminum oxide, with tetrahedral and octahedral crystal forms. For example, spinel-type lithium manganese oxide materials have outstanding characteristics such as high specific capacity, low cost and low environmental pollution. Olivine structure phosphate materials and spinel materials are used as the first active material, which is beneficial to improving the performance of the battery.
  • the olivine structure phosphate material includes Li a Fe b M 1-b P 1-m O 4-n , wherein M includes at least one of other metal elements except Fe, wherein 0 ⁇ a ⁇ 1.1, 0.3 ⁇ b ⁇ 1, 0 ⁇ m ⁇ 0.1, 0 ⁇ n ⁇ 0.1, optionally, M includes at least one of Mn, Al, Cu, Mg, Zn, Ni, Ti, V, Zr, Co, Ga, Sn, Sb, Nb and Ge, optionally, the olivine structure phosphate material includes at least one of LiFePO 4 and LiMnFePO 4 .
  • LiaFebM1 -bP1 - mO4 -n includes the molar content of lithium under different charge and discharge states of the battery (usually the battery voltage is between 2V and 5V).
  • LiFePO 4 and LiMnFePO 4 are merely an exemplary description of the substances used as the first active material in the embodiments of the present application, and do not constitute a limitation on the first active material of the present application.
  • LiFePO 4 has the advantages of long cycle life, good thermal stability, high energy density, etc.
  • LiMnFePO 4 also has the advantages of long cycle life, good thermal stability, etc.
  • LiFePO 4 and LiMnFePO 4 are used as the first active material to improve the cycle performance, energy density and safety of the battery.
  • the spinel material includes LiNi c Mn 2-c O 4 , wherein 0 ⁇ c ⁇ 2.
  • the spinel material includes lithium manganate (LiMn 2 O 4 ).
  • LiMn 2 O 4 is only an exemplary description of the substance used as the first active material in the embodiments of the present application, and does not constitute a limitation on the first active material of the present application.
  • LiMn 2 O 4 used as positive electrode active material has the advantages of low price, high potential, environmental friendliness, high safety performance and good rate performance.
  • the second active material includes a layered transition metal oxide.
  • Layered transition metal oxides are a class of oxides with a multilayer (generally two-dimensional) structure, which are obtained based on the redox reaction of transition metal cations with lattice oxygen anions and have high energy and high power density. Layered transition metal oxides can be used as the second active material to improve the energy density of batteries.
  • the layered transition metal oxide includes at least one of LiCoO 2 , LiMnO 2 , LiNiO 2 , Li a' Ni x Co y M 1 1-xy O 2+d , and zLi 2 MnO 3 ⁇ (1-z)LiM 2 O 2 , wherein M 1 includes at least one of Mn, Zr, Al, B, Ta, Mo, W, Nb, Sb, and La, and M 2 includes at least one of Co, Ni, and Mn, 0.5 ⁇ x ⁇ 1.0, 0 ⁇ y ⁇ 0.5, x+y ⁇ 1, 0.2 ⁇ a' ⁇ 1.2, -0.02 ⁇ d ⁇ 0.02, and 0 ⁇ z ⁇ 1.
  • the layered transition metal oxide includes Li(Ni 0.6 Co 0.2 Mn 0.2 ) 1.15 O 2 , Li(Ni 0.5 Co 0.2 Mn 0.3 ) 1.07 O 2 At least one of the 2 .
  • Lithium nickel cobalt manganese oxide (NCM) used as positive electrode active material has the advantages of high energy density, high voltage platform, good thermal stability and good cycle performance.
  • NCM is only an exemplary description of the substance used as the second active material in the embodiments of the present application, and does not constitute a limitation on the second active material of the present application.
  • the second active material may include ternary materials, lithium-rich manganese-based materials, and disordered rock salt phase structure materials.
  • Ternary materials refer to materials composed of three chemical components (elements) and components (single substances and compounds).
  • ternary materials used as positive electrode active materials for batteries are usually synthesized from nickel salts, cobalt salts, and manganese salts/aluminum salts. The ratio of nickel, cobalt, and manganese (or nickel, cobalt, and aluminum) in the ternary materials can be adjusted according to actual needs, and has the advantages of high energy density and good cycle performance.
  • Ternary materials, lithium-rich manganese-based materials, and disordered rock salt phase structure materials are used as second active materials to improve the performance of batteries.
  • the conductive layer 13 includes a conductive agent and a binder.
  • Conductive agents collect microcurrents between active materials to reduce the contact resistance of the electrode and accelerate the movement of electrons. They can also effectively increase the migration rate of metal ions in the electrode material, thereby improving the charge and discharge efficiency of the electrode. Binders can bond the active material to the conductive agent, enhance the electrical contact between the active material and the conductive agent, and stabilize the structure of the positive electrode.
  • the conductive layer 13 does not include active materials, but only includes a conductive agent and a binder.
  • the conductive layer 13 is a porous film having a conductive agent and a binder.
  • the conductive layer 13 may be bonded to the first coating layer 11 and the second coating layer 12 , thereby reducing the risk of deformation and wrinkling of the positive electrode plate 1 .
  • the conductive agent includes at least one of conductive carbon black, superconducting carbon, carbon dots, Ketjen black and carbon nanotubes.
  • carbon material conductive agents Due to the unique composition of carbon structure, carbon material conductive agents have good conductivity.
  • conductive carbon black has low resistance and high conductivity, small particle size, large and rough specific surface area, high structure, clean surface (few compounds), etc.
  • Ketjen black has a unique branched morphology, so it has high conductivity; carbon atoms in carbon nanotubes adopt SP 2 hybridization, so they have high modulus and high strength. Carbon nanotubes also have good flexibility, stretchability and conductivity.
  • Conductive carbon black, superconducting carbon, carbon dots, Ketjen black and carbon nanotubes can improve the conductivity of batteries as conductive agents.
  • the binder includes polyvinylidene fluoride, styrene polybutadiene rubber, polytetrafluoroethylene, vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-trichloroethylene copolymer and at least one of fluorine-containing acrylic resin, polyacrylonitrile, polyvinyl pyrrolidone, polyvinyl acetate, polyethylene-co-vinyl acetate, polyethylene oxide, and polyarylate.
  • fluorine-containing acrylic resin polyacrylonitrile, polyvinyl pyrrolidone, polyvinyl acetate, polyethylene-co-viny
  • the thickness d3 of the conductive layer 13 is 1 ⁇ m to 15 ⁇ m.
  • the thickness d3 of the conductive layer 13 is 5 ⁇ m to 10 ⁇ m.
  • the thickness d3 of the conductive layer 13 may be 1 ⁇ m, 2 ⁇ m, 3 ⁇ m, 4 ⁇ m, 5 ⁇ m, 6 ⁇ m, 7 ⁇ m, 8 ⁇ m, 9 ⁇ m, 10 ⁇ m, 11 ⁇ m, 12 ⁇ m, 13 ⁇ m, 14 ⁇ m, 15 ⁇ m, or a value between any two of the above values.
  • the thickness of the conductive layer 13 should not be too small, so that the conductive layer 13 can effectively isolate the first active material from the second active material.
  • the thickness of the conductive layer 13 should not be too large, so as to ensure that the content of active material in the positive electrode plate is not too small, thereby ensuring the energy density of the battery.
  • the thickness d1 of the first coating 11 is 40 ⁇ m to 160 ⁇ m.
  • the thickness d1 of the first coating 11 is 70 ⁇ m to 140 ⁇ m.
  • the thickness d1 of the first coating 11 may be 40 ⁇ m, 50 ⁇ m, 60 ⁇ m, 70 ⁇ m, 80 ⁇ m, 90 ⁇ m, 100 ⁇ m, 110 ⁇ m, 120 ⁇ m, 130 ⁇ m, 140 ⁇ m, 150 ⁇ m, 160 ⁇ m, or a value between any two of the above values.
  • the thickness of the first coating 11 should not be too large to reduce the waste of the first active material and the total volume of the battery, thereby reducing production costs.
  • the thickness of the first coating should not be too small to ensure that the content of the first active material in the positive electrode sheet is not too small, which is beneficial to improving battery performance.
  • the thickness d2 of the second coating 12 is 40 ⁇ m to 80 ⁇ m.
  • the thickness d2 of the second coating 12 is 40 ⁇ m to 60 ⁇ m.
  • the thickness d2 of the second coating layer 12 may be 40 ⁇ m, 50 ⁇ m, 60 ⁇ m, 70 ⁇ m, 80 ⁇ m, or a value between any two of the above values.
  • the thickness of the second coating should not be too large to reduce the waste of the second active material and reduce the total volume of the battery, thereby reducing production costs.
  • the thickness of the second coating should not be too small to ensure that the content of the second active material in the positive electrode sheet is not too small, which is beneficial to improving battery performance.
  • the weight percentage of the binder in the conductive layer is 1 wt % to 10 wt %, and optionally, 3 wt % to 7 wt %.
  • the weight percentage of the binder in the conductive layer can be 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, or a value between any two of the above values.
  • the weight percentage of the conductive agent in the conductive layer is 90 wt % to 99 wt %, and optionally, 93 wt % to 97 wt %.
  • the weight percentage of the conductive agent in the conductive layer is 90wt%, 91wt%, 92wt%, 93wt%, 94wt%, 95wt%, 96wt%, 97wt%, 98wt%, 99wt%, or a value between any two of the above values.
  • the conductive agent in the conductive layer collects microcurrents between active materials to reduce the contact resistance of the electrode and accelerate the movement rate of electrons. It can also effectively increase the migration rate of metal ions in the electrode material, thereby improving the charge and discharge efficiency of the electrode. If the content of the conductive agent is too little, it will reduce the electron conduction channel in the positive electrode sheet, resulting in low utilization of the positive electrode active material, thereby reducing the cycle performance and energy density of the battery. Therefore, setting the content of the conductive agent in the conductive layer to 90wt% to 99wt% is beneficial to improving the overall performance of the battery.
  • the conductive layer 13 can effectively play its role of isolating and electrically connecting the first active material and the second active material. to enhance the overall performance of the battery.
  • the weight percentage of the first active material is 90 wt % to 98 wt %, and optionally, 96 wt % to 97 wt %.
  • the weight percentage of the first active material in the first coating can be 90wt%, 91wt%, 92wt%, 93wt%, 94wt%, 95wt%, 96wt%, 97wt%, 98wt%, or a value between any two of the above values.
  • the weight percentage of the conductive agent in the first coating layer is 0.1 wt% to 1 wt%, and optionally, 0.4 wt% to 0.6 wt%.
  • the weight percentage of the conductive agent in the first coating can be 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1wt%, or a value between any two of the above values.
  • the weight percentage of the binder in the first coating can be 1wt%, 1.1wt%, 1.2wt%, 1.3wt%, 1.4wt%, 1.5wt%, 1.6wt%, 1.7wt%, 1.8wt%, 1.9wt%, 2wt%, or a value between any two of the above values.
  • the weight percentage of the second active material is 90 wt % to 98 wt %, and optionally 96 wt % to 97 wt %.
  • the weight percentage of the second active material in the second coating can be 90wt%, 91wt%, 92wt%, 93wt%, 94wt%, 95wt%, 96wt%, 97wt%, 98wt%, or a value between any two of the above values.
  • the weight percentage of the conductive agent in the second coating layer can be 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1wt%, or any of the above. A value between two values.
  • the weight percentage of the binder in the second coating layer is 1 wt % to 2 wt %, and optionally, 1.2 wt % to 1.4 wt %.
  • the weight percentage of the binder in the first coating can be 1wt%, 1.1wt%, 1.2wt%, 1.3wt%, 1.4wt%, 1.5wt%, 1.6wt%, 1.7wt%, 1.8wt%, 1.9wt%, 2wt%, or a value between any two of the above values.
  • the weight contents of the second active material, the conductive agent and the binder in the second coating layer 12 are set within an appropriate range, so that the second active material can effectively function.
  • Fig. 3 is a method for preparing a positive electrode sheet according to an embodiment of the present application. As shown in Fig. 3, method 300 includes the following steps.
  • Step 310 providing a positive electrode current collector, and disposing a first coating layer, a second coating layer and a conductive layer on the positive electrode current collector.
  • the first coating is disposed on the surface of at least one side of the positive electrode current collector, the conductive layer is disposed between the first coating and the second coating, the first coating includes a first active material, the second coating includes a second active material, and the second active material is different from the first active material.
  • the positive electrode sheet prepared by the above method is beneficial to improving the performance of the battery when applied to the battery.
  • the negative electrode current collector has two surfaces opposite to each other in its thickness direction, and the negative electrode film layer is disposed on any one or both of the two opposite surfaces of the negative electrode current collector.
  • the negative electrode current collector may be a metal foil or a composite current collector.
  • a metal foil a copper foil may be used.
  • 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 may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material base (such as polypropylene (PP), ... It is formed on a substrate such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.
  • PET polyethylene terephthalate
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the negative electrode active material may adopt the negative electrode active material for the battery known in the art.
  • the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc.
  • the silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys.
  • the tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys.
  • the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.
  • the negative electrode film layer may further include a binder.
  • the binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).
  • the negative electrode film layer may further include a conductive agent, which may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • a conductive agent which may 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 film layer may optionally include other additives, such as a thickener (eg, sodium carboxymethyl cellulose (CMC-Na)).
  • a thickener eg, sodium carboxymethyl cellulose (CMC-Na)
  • the negative electrode sheet can be prepared in the following manner: the components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the 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 collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.
  • a solvent such as deionized water
  • the electrolyte is an electrolyte solution, which includes an electrolyte salt and a solvent.
  • the electrolyte salt can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.
  • the solvent can be selected from at least one of 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, 1,4-butyrolactone, cyclopentane sulfone, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.
  • the electrolyte may further include additives, such as negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.
  • additives such as negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.
  • the battery cell further includes a separator.
  • the present application has no particular limitation on the type of separator, and any known porous separator with good chemical stability and mechanical stability can be selected.
  • the material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.
  • the isolation membrane can be a single-layer film or a multi-layer composite film, without particular limitation.
  • the materials of each layer can be the same or different, without particular limitation.
  • the positive electrode sheet, the negative electrode sheet, and the separator may be formed into an electrode assembly by a winding process or a lamination process.
  • the embodiment of the present application also provides a battery cell.
  • the battery cell includes the positive electrode sheet, negative electrode sheet, electrolyte and separator in the above embodiment.
  • active ions are embedded and released back and forth between the positive electrode sheet and the negative electrode sheet.
  • the electrolyte plays the role of conducting ions between the positive electrode sheet and the negative electrode sheet.
  • the separator is arranged between the positive electrode sheet and the negative electrode sheet, mainly to prevent the positive and negative electrodes from short-circuiting, and at the same time to allow ions to pass through.
  • the “embedding” process described in this application refers to the process in which active ions are embedded in the positive electrode active material or the negative electrode active material due to an electrochemical reaction
  • the “extraction” and “de-embedding” processes described in this application refer to the process in which active ions are extracted from the positive electrode active material or the negative electrode active material due to an electrochemical reaction.
  • the battery cell may include an outer packaging, which may be used to encapsulate the electrode assembly and the electrolyte.
  • the outer packaging of the battery cell may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc.
  • the outer packaging of the battery cell may also be a soft package, such as a bag-type soft package.
  • the material of the soft package may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, and polybutylene succinate.
  • FIG4 is a battery cell 20 of a square structure as an example.
  • the outer package may include a shell 21 and a cover plate 23.
  • the shell 21 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity.
  • the shell 21 has an opening connected to the receiving cavity, and the cover plate 23 can be covered on the opening to close the receiving cavity.
  • the positive electrode sheet, the negative electrode sheet and the isolation film can form an electrode assembly 22 through a winding process or a lamination process.
  • the electrode assembly 22 is encapsulated in the receiving cavity.
  • the electrolyte is infiltrated in the electrode assembly 22.
  • the number of electrode assemblies 22 contained in the battery cell 20 can be one or more, and those skilled in the art can select according to specific actual needs.
  • the battery 10 may include a plurality of battery cells 20.
  • FIG. 6 a schematic diagram of the structure of a battery 10 according to an embodiment of the present application is shown, and the battery 10 may include a plurality of battery cells 20.
  • the battery 10 may also include a housing 11, the interior of the housing 11 is a hollow structure, and the plurality of battery cells 20 are accommodated in the housing 11.
  • the plurality of battery cells 20 are connected in parallel, in series, or in a mixed combination and then placed in the housing 11.
  • the battery 10 may also include other structures, which are not described one by one here.
  • the battery 10 may also include a busbar component, which is used to realize electrical connection between multiple battery cells 20, such as parallel connection, series connection or mixed connection.
  • the busbar component can realize electrical connection between the battery cells 20 by connecting the electrode terminals of the battery cells 20.
  • the busbar component can be fixed to the electrode terminals of the battery cells 20 by welding.
  • the electrical energy of multiple battery cells 20 can be further led out through the box 11 through a conductive mechanism.
  • the conductive mechanism may also belong to the busbar component.
  • the number of battery cells 20 can be set to any value according to different power requirements. Multiple battery cells 20 can be connected in series, parallel or mixed to achieve a larger capacity or power. The number of battery cells 20 included in 10 may be large. For ease of installation, the battery cells 20 may be arranged in groups, and each group of battery cells 20 constitutes a battery module. The number of battery cells 20 included in the battery module is not limited and can be set according to requirements. The battery may include multiple battery modules, which may be connected in series, in parallel, or in a mixed manner.
  • the present application also provides an electric device, which includes at least one of the battery cells, battery modules or batteries provided in the present application.
  • the battery cells, battery modules or batteries can be used as the power source of the electric device, and can also be used as the energy storage unit of the electric device.
  • the electric device may 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 are not limited thereto.
  • a battery cell, a battery module or a battery can be selected according to its usage requirements.
  • Fig. 7 is an example of an electric device.
  • the electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.
  • batteries or battery modules may be used.
  • a device may be a mobile phone, a tablet computer, a notebook computer, etc. Such a device is usually required to be light and thin, and a battery cell may be used as a power source.
  • Positive electrode sheet 1 Lithium iron phosphate (LiFePO 4 ), conductive carbon black, carbon nanotubes (CNT), and polyvinylidene fluoride (PVDF) are dissolved in a solvent of N-methylpyrrolidone (NMP) at a weight ratio of 97.6:0.6:0.4:1.4, and the mixture is stirred and mixed to form a first coating.
  • NMP N-methylpyrrolidone
  • Lithium nickel cobalt manganese oxide (NCM622), conductive carbon black, CNT, and PVDF were dissolved in a solvent NMP at a weight ratio of 97.6:0.6:0.4:1.4, and the second coating was prepared after being stirred and mixed evenly.
  • the binder carboxymethyl cellulose (CMC) and the conductive agent conductive carbon black are dissolved in the solvent deionized water at a weight ratio of 3:97, and the conductive layer is prepared after being stirred and mixed evenly.
  • the first coating layer, the second coating layer, and the conductive layer are applied to the positive electrode collector simultaneously or step by step according to the structure of the positive electrode sheet shown in FIG. 1 or FIG. 2 in the embodiment of the present application by extrusion coating (for example, the first coating layer, the second coating layer, and the conductive layer can be applied to the positive electrode collector simultaneously by using an LOM extrusion coater) to obtain a positive electrode sheet 1.
  • extrusion coating for example, the first coating layer, the second coating layer, and the conductive layer can be applied to the positive electrode collector simultaneously by using an LOM extrusion coater
  • the thickness of the first coating layer is 130 ⁇ m
  • the thickness of the second coating layer is 50 ⁇ m
  • the thickness of the conductive layer is 1 ⁇ m.
  • Positive electrode sheet 2 is different from positive electrode sheet 1, except that the thickness of the conductive layer is 5 ⁇ m, thereby obtaining positive electrode sheet 2.
  • Positive electrode sheet 3 is different from positive electrode sheet 1, except that the thickness of the conductive layer is 10 ⁇ m, so as to obtain positive electrode sheet 3.
  • Positive electrode sheet 4 is different from positive electrode sheet 1 in that the thickness of the conductive layer is 15 ⁇ m, thereby obtaining positive electrode sheet 4.
  • Positive electrode sheet 5 is different from positive electrode sheet 2 in that the thickness of the first coating layer is 40 ⁇ m, thereby obtaining positive electrode sheet 5.
  • Positive electrode sheet 6 is different from positive electrode sheet 2 in that the thickness of the first coating layer is 70 ⁇ m, thereby obtaining positive electrode sheet 6.
  • Positive electrode sheet 7 is different from positive electrode sheet 2 in that the thickness of the first coating layer is 140 ⁇ m, thereby obtaining positive electrode sheet 7.
  • Positive electrode sheet 8 is different from positive electrode sheet 2 in that the thickness of the first coating layer is 160 ⁇ m, thereby obtaining positive electrode sheet 8.
  • Positive electrode sheet 9 is different from positive electrode sheet 2 in that the thickness of the second coating layer is 40 ⁇ m, thereby obtaining positive electrode sheet 9.
  • Positive electrode sheet 10 The positive electrode sheet 10 is different from the positive electrode sheet 2 in that the thickness of the second coating layer is 60 ⁇ m, and the positive electrode sheet 10 is obtained.
  • Positive electrode sheet 11 The positive electrode sheet 11 is different from the positive electrode sheet 2 in that the thickness of the second coating layer is 80 ⁇ m, thereby obtaining the positive electrode sheet 11.
  • Positive electrode sheet 12 is different from positive electrode sheet 2 in that lithium manganese iron phosphate (LiMnFePO 4 ), conductive carbon black, CNT, and PVDF are dissolved in a solvent NMP at a weight ratio of 97.6:0.6:0.4:1.4, and a first coating layer is formed after being stirred and mixed evenly.
  • the thickness of the first coating layer is 130 ⁇ m, and the positive electrode sheet 12 is obtained.
  • Positive electrode sheet 13 is different from positive electrode sheet 2 in that LiCoO 2 , conductive carbon black, CNT, and PVDF are dissolved in a solvent NMP at a weight ratio of 97.6:0.6:0.4:1.4, and then stirred and mixed to form a second coating layer with a thickness of 50 ⁇ m, thereby obtaining positive electrode sheet 13.
  • Positive electrode sheet 14 The positive electrode sheet 14 is different from the positive electrode sheet 2 , except that the thickness of the conductive layer is 20 ⁇ m. Positive electrode sheet 14 is obtained.
  • Positive electrode sheet 15 The difference between the positive electrode sheet 15 and the positive electrode sheet 2 is that the thickness of the first coating layer is 30 ⁇ m, so as to obtain the positive electrode sheet 15 .
  • Positive electrode sheet 16 is different from positive electrode sheet 2 in that the thickness of the first coating layer is 170 ⁇ m, thereby obtaining positive electrode sheet 16.
  • Positive electrode sheet 17 is different from positive electrode sheet 2 in that the thickness of the second coating layer is 30 ⁇ m, thereby obtaining positive electrode sheet 17.
  • Positive electrode sheet 18 is different from positive electrode sheet 2 in that the thickness of the second coating layer is 90 ⁇ m, thereby obtaining positive electrode sheet 18 .
  • Positive electrode sheet 19 is different from positive electrode sheet 2 in that the weight ratio of the binder CMC and the conductive agent conductive carbon black in the conductive layer is 10:90, thereby obtaining positive electrode sheet 19.
  • Positive electrode sheet 20 is different from positive electrode sheet 2 in that the weight ratio of the binder CMC and the conductive agent conductive carbon black in the conductive layer is 7:93, thereby obtaining positive electrode sheet 20 .
  • Positive electrode sheet 21 is different from positive electrode sheet 2 in that the weight ratio of the binder CMC and the conductive agent conductive carbon black in the conductive layer is 1:99, thereby obtaining positive electrode sheet 21.
  • Positive electrode sheet 22 The positive electrode sheet 22 is different from the positive electrode sheet 2, but no conductive layer is provided to obtain the positive electrode sheet 22.
  • isolation film A conventional polypropylene film was used as the isolation film.
  • Assembly of lithium-ion batteries stack the positive electrode sheet, separator, and negative electrode sheet in order, with the separator placed between the positive electrode sheet and the negative electrode sheet to serve as an isolation, and then wind them to obtain an electrode assembly; place the electrode assembly in a battery case, inject electrolyte after drying, and then undergo formation, standing, and other processes to obtain a lithium-ion battery.
  • Example 1 A lithium-ion battery obtained by assembling a positive electrode sheet 1, a separator, a negative electrode sheet, and an electrolyte according to the above method is Example 1.
  • Example 3 The lithium-ion battery obtained by assembling the positive electrode sheet 3, the separator, the negative electrode sheet and the electrolyte according to the above method is Example 3.
  • Example 5 A lithium-ion battery obtained by assembling a positive electrode sheet 5, a separator, a negative electrode sheet, and an electrolyte according to the above method is Example 5.
  • Example 7 The lithium-ion battery obtained by assembling the positive electrode sheet 7, the separator, the negative electrode sheet and the electrolyte according to the above method is Example 7.
  • Example 8 The lithium-ion battery obtained by assembling the positive electrode sheet 8, the separator, the negative electrode sheet, and the electrolyte according to the above method is Example 8.
  • Example 9 A lithium-ion battery obtained by assembling a positive electrode sheet 9, a separator, a negative electrode sheet, and an electrolyte according to the above method is Example 9.
  • Example 10 A lithium-ion battery obtained by assembling the positive electrode sheet 10, the separator, the negative electrode sheet, and the electrolyte according to the above method is Example 10.
  • Example 11 A lithium-ion battery obtained by assembling a positive electrode sheet 11, a separator, a negative electrode sheet, and an electrolyte according to the above method is Example 11.
  • Example 12 A lithium-ion battery obtained by assembling the positive electrode sheet 12, the separator, the negative electrode sheet, and the electrolyte according to the above method is Example 12.
  • Example 13 The lithium-ion battery obtained by assembling the positive electrode sheet 13, the isolation membrane, the negative electrode sheet, and the electrolyte according to the above method is Example 13.
  • Example 14 A lithium-ion battery obtained by assembling a positive electrode sheet 14, a separator, a negative electrode sheet, and an electrolyte according to the above method is Example 14.
  • Example 15 A lithium-ion battery obtained by assembling the positive electrode sheet 15, the isolation membrane, the negative electrode sheet, and the electrolyte according to the above method is Example 15.
  • Example 16 A lithium-ion battery obtained by assembling a positive electrode sheet 16, a separator, a negative electrode sheet, and an electrolyte according to the above method is Example 16.
  • Example 17 A lithium-ion battery obtained by assembling a positive electrode sheet 17, a separator, a negative electrode sheet, and an electrolyte according to the above method is Example 17.
  • Example 18 The lithium-ion battery obtained by assembling the positive electrode sheet 18, the isolation membrane, the negative electrode sheet, and the electrolyte according to the above method is Example 18.
  • Example 19 The lithium-ion battery obtained by assembling the positive electrode sheet 19, the isolation membrane, the negative electrode sheet, and the electrolyte according to the above method is Example 19.
  • Example 20 The lithium-ion battery obtained by assembling the positive electrode sheet 20, the isolation membrane, the negative electrode sheet, and the electrolyte according to the above method is Example 20.
  • Example 21 A lithium-ion battery obtained by assembling a positive electrode sheet 21, a separator, a negative electrode sheet, and an electrolyte according to the above method is Example 21.
  • Comparative Example 1 A lithium-ion battery obtained by assembling the positive electrode sheet 22, the separator, the negative electrode sheet, and the electrolyte according to the above method is Comparative Example 1.
  • the battery cell is first charged to 4.3V at a constant current of 1C, and then further charged to a current of 0.05C at a constant voltage of 4.3V, and then discharged to 3V at a constant current of 1C.
  • This is a charge and discharge cycle process, and the discharge capacity this time is the discharge capacity of the first cycle.
  • the battery is subjected to multiple cycle charge and discharge tests in the above manner, and the discharge capacity of the 200th cycle is detected, and the capacity retention rate of the battery cell after the cycle is calculated by the following formula.
  • Capacity retention rate of the battery after 200 cycles (%) [discharge capacity of the 200th cycle / discharge capacity of the 200th cycle / capacity ... Discharge capacity for 1 cycle] ⁇ 100%.
  • the thickness of the conductive layer needs to be set within an appropriate range. If the thickness of the conductive layer is too large, the proportion of active material in the active material layer will be reduced, which will reduce the energy density of the battery.

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Abstract

本申请实施例提供一种正极极片及其制备方法、电池单体、电池和用电装置。该正极极片包括：正极集流体；第一涂层，第一涂层设置于正极集流体的至少一侧的表面，第一涂层包括第一活性材料；第二涂层，第二涂层包括第二活性材料，第二活性材料与第一活性材料不同；导电层，导电层设置于第一涂层和第二涂层之间，用于隔离所述第一涂层和所述第二涂层。包含该正极极片的电池的性能有所提升。

Description

正极极片及其制备方法、电池单体、电池和用电装置 技术领域
本申请涉及电池技术领域，特别是涉及一种正极极片及其制备方法、电池单体、电池和用电装置。
背景技术
近年来，锂离子电池的应用范围越来越广泛，其广泛应用于水力、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。
正极极片作为电池的组成部分，正极极片的性能对于电池的性能至关重要。因此，如何提供一种正极极片，以提高电池的性能是一项亟待解决的技术问题。
发明内容
本申请实施例提供了一种正极极片及其制备方法、电池单体、电池和用电装置，以提高电池的性能。
第一方面，提供了一种正极极片，包括：正极集流体；第一涂层，所述第一涂层设置于所述正极集流体的至少一侧的表面，所述第一涂层包括第一活性材料；第二涂层，所述第二涂层包括第二活性材料，所述第二活性材料与所述第一活性材料不同；导电层，所述导电层设置于所述第一涂层和所述第二涂层之间，用于隔离所述第一涂层和所述第二涂层。
本申请实施例提供了一种正极极片，包括正极集流体、第一涂层、第二涂层和导电层。具体地，第一涂层设置于正极集流体的至少一侧的表面，导电层设置于第一涂层和第二涂层之间。其中第一涂层包括的第一活性材料和第二涂层包括的第二活性材料不同，也就是说，正极活性材料包括第一活性材料和第二活性材料两种不同的材料，这样，正极极片提供的正极活性材料可以兼具第一活性材料和第二活性材料 的优点，从而有利于提高电池的整体性能。另一方面，由于第一活性材料和第二活性材料的材料性质差异，比如，电子电导率不同，若第一活性材料和第二活性材料直接接触，两种材料的性质差异会使两者之间互相影响，两种活性材料的性能降低而影响电池的性能。因此利用导电层将第一涂层和第二涂层隔开，避免第一活性材料和第二活性材料直接接触，同时电连接第一活性材料和第二活性材料。也就是说，导电层的设置既避免第一活性材料和第二活性材料直接接触，又能够保证第一活性材料和第二活性材料之间的电连接，使得第一活性材料和第二活性材料能够发挥各自的优点，使得电池的整体性能有所提升。
在一种可能的实现方式中，所述第一活性材料包括橄榄石结构磷酸盐材料、尖晶石材料中的至少一种。
橄榄石结构为材料的一种晶体结构，具有橄榄石结构的材料具有较高的稳定性，在应用于电池单体时，可以降低电池单体在高温等条件下发生起火、爆炸的风险，有利于提高电池单体的可靠性。橄榄石结构磷酸盐具有较高的理论比容量、较好的循环稳定性、低成本和环境友好等优点。尖晶石是镁铝氧化物组成的矿物，具有四面体晶形和八面体晶形，比如，尖晶石型锰酸锂材料具有比容量较高、成本低廉、环境污染小等突出特点。橄榄石结构磷酸盐材料、尖晶石材料用作第一活性材料，有利于提高电池的性能。
在一种可能的实现方式中，所述橄榄石结构磷酸盐材料包括LiaFebM1-bP1- mO4-n，其中，M包括除Fe外的其它金属元素中的至少一种，其中，0≤a≤1.1，0.3≤b≤1，0≤m≤0.1，0≤n≤0.1，可选地，M包括Mn、Al、Cu、Mg、Zn、Ni、Ti、V、Zr、Co、Ga、Sn、Sb、Nb和Ge中的至少一种，可选地，所述橄榄石结构磷酸盐材料包括磷酸铁锂(LiFePO4)、磷酸锰铁锂(LiMnFePO4)中的至少一种。
磷酸铁锂具有循环寿命长、热稳定性好、能量密度高等优点；磷酸锰铁锂同样具有循环寿命长、热稳定性好等优点。磷酸铁锂、磷酸锰铁锂用作第一活性材料，可以提高电池的循环性能、能量密度和安全性。
在一种可能的实现方式中，所述尖晶石材料包括LiNicMn2-cO4，其中0≤c＜2，可选地，所述尖晶石材料包括锰酸锂(LiMn2O4)。
锰酸锂用作正极活性材料具有价格低、电位高、环境友好、安全性能高、 倍率性能好等优点。
在一种可能的实现方式中，所述第二活性材料包括层状过渡金属氧化物。
作为电池正极活性材料的层状过渡金属氧化物是一类具有多层(一般为二维)结构的氧化物，是基于过渡金属阳离子与晶格氧阴离子氧化还原反应获得的，具有高能量和高功率密度。层状过渡金属氧化物用作第二活性材料可以提高电池的能量密度。
可选地，所述层状过渡金属氧化物包括LiCoO2、LiMnO2、LiNiO2、Lia’NixCoyM1 1-x-yO2+d、zLi2MnO3·(1-z)LiM2O2中的至少一种，其中，M1包括Mn、Zr、Al、B、Ta、Mo、W、Nb、Sb、La中的至少一种，M2包括Co、Ni、Mn中的至少一种，0.5≤x≤1.0，0≤y＜0.5，x+y＜1，0.2≤a’＜1.2，-0.02≤d<0.02，0＜z＜1，可选地，所述层状过渡金属氧化物包括Li(Ni0.6Co0.2Mn0.2)1.15O2、Li(Ni0.5Co0.2Mn0.3)1.07O2中的至少一种。
镍钴锰酸锂(NCM)用作正极活性材料具有能量密度高、电压平台高、热稳定性好、循环性能好等优点。
在一种可能的实现方式中，所述导电层包括导电剂和粘结剂。
导电剂在活性材料之间起到收集微电流的作用，以减小电极的接触电阻加速电子的移动速率，同时也能有效地提高金属离子在电极材料中的迁移速率，从而提高电极的充放电效率。粘结剂可以使活性材料与导电剂之间粘结，增强活性材料与导电剂之间的电接触，还可以稳定正极极片的结构。
在一种可能的实现方式中，所述导电剂包括导电炭黑、超导碳、碳点、科琴黑和碳纳米管中的至少一种。
由于碳结构的独特组成成分，碳材料导电剂具备良好的导电性能。比如，导电炭黑具有低电阻属性和高导电性能，粒径小，比表面积大且粗糙，结构高，表面洁净(化合物少)等优点；科琴黑具有独特的支链状形态，因而导电性高；碳纳米管中碳原子采取SP2杂化，因而具有高模量和高强度，碳纳米管还具有良好的柔韧性、可拉伸性和导电性能。导电炭黑、超导碳、碳点、科琴黑和碳纳米管作为导电剂可以提升电池的导电性能。
在一种可能的实现方式中，所述粘结剂包括聚偏氟乙烯、苯乙烯聚丁橡胶、 聚四氟乙烯、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、偏二氟乙烯-六氟丙烯共聚物、偏二氟乙烯-三氯乙烯共聚物及含氟丙烯酸酯树脂、聚丙烯腈、聚乙烯吡咯烷酮、聚醋酸乙烯酯、聚乙烯-共-醋酸乙烯酯、聚环氧乙烷、聚芳酯中的至少一种。
在一种可能的实现方式中，所述导电层的厚度为1μm～15μm，可选地，所述导电层的厚度为5μm～10μm。一方面，导电层的厚度不宜过小，这样可以使得导电层能够有效隔离第一活性材料与第二活性材料，另一方面，导电层的厚度不宜过大，这样可以保证正极极片中活性材料含量不会过少，以保证电池的能量密度。
在一种可能的实现方式中，所述第一涂层的厚度为40μm～160μm，可选地，所述第一涂层的厚度为70μm～140μm。第一涂层厚度不宜过大，以减少第一活性材料的浪费和减小电池的总体积，降低生产成本，第一涂层厚度也不宜过小，以保证正极极片中的第一活性材料的含量不会过少，有利于电池性能的提升。
在一种可能的实现方式中，所述第二涂层的厚度为40μm～80μm，可选地，所述第二涂层的厚度为40μm～60μm。第二涂层厚度不宜过大，以减少第二活性材料的浪费和减小电池的总体积，降低生产成本，第二涂层厚度也不宜过小，以保证正极极片中的第二活性材料的含量不会过少，有利于电池性能的提升。
在一种可能的实现方式中，基于所述导电层的总重量计，所述导电层中的粘结剂的重量百分含量为1wt％～10wt％，可选地，为3wt％～7wt％。
在一种可能的实现方式中，基于所述导电层的总重量计，所述导电层中的导电剂的重量百分含量为90wt％～99wt％，可选地，为93wt％～97wt％。
导电层中的导电剂在活性材料之间起到收集微电流的作用，以减小电极的接触电阻加速电子的移动速率，同时也能有效地提高金属离子在电极材料中的迁移速率，从而提高电极的充放电效率。导电剂的含量太少，会减少正极极片中的电子导通通道，使得正极活性物质的利用率低，从而降低电池的循环性能和能量密度。
上述技术方案中，通过设置导电层中的导电剂和粘接剂的重量含量在适宜范围内，使得导电层可以有效发挥其隔离和电连接第一活性材料和第二活性材料的作用，以提升电池的整体性能。
在一种可能的实现方式中，基于所述第一涂层的总重量计，所述第一活性 材料的重量百分含量为90wt％～98wt％，可选地，为96wt％～97wt％。
在一种可能的实现方式中，基于所述第一涂层的总重量计，所述第一涂层中的导电剂的重量百分含量为0.1wt％～1wt％，可选地，为0.4wt％～0.6wt％。
在一种可能的实现方式中，基于所述第一涂层的总重量计，所述第一涂层中的粘结剂的重量百分含量为1wt％～2wt％，可选地，为1.2wt％～1.4wt％。
上述技术方案中，通过设置第一涂层中的第一活性材料、导电剂和粘接剂的重量含量在适宜范围内，使得第一活性材料能够有效发挥作用。
在一种可能的实现方式中，基于所述第二涂层的总重量计，所述第二活性材料的重量百分含量为90wt％～98wt％，可选地，为96wt％～97wt％。
在一种可能的实现方式中，基于所述第二涂层的总重量计，所述第二涂层中的导电剂的重量百分含量为0.1wt％～1wt％，可选地，为0.4wt％～0.6wt％。
在一种可能的实现方式中，基于所述第二涂层的总重量计，所述第二涂层中的粘结剂的重量百分含量为1wt％～2wt％，可选地，为1.2wt％～1.4wt％。
上述技术方案中，通过设置第二涂层中的第二活性材料、导电剂和粘接剂的重量含量在适宜范围内，使得第二活性材料能够有效发挥作用。
第二方面，提供了一种正极极片的制备方法，包括：提供正极集流体，在所述正极集流体上设置第一涂层、第二涂层和导电层；其中，所述第一涂层设置于所述正极集流体的至少一侧的表面，所述导电层设置于所述第一涂层和所述第二涂层之间，所述第一涂层包括第一活性材料，所述第二涂层包括第二活性材料，所述第二活性材料与所述第一活性材料不同。
第三方面，提供了一种电池单体，包括第一方面及其中任一项可能的实现方式中的正极极片。
第四方面，提供了一种电池，包括第三方面所述的电池单体。
第五方面，提供了一种用电装置，包括第四方面所述的电池。
本申请实施例提供了一种正极极片，包括正极集流体、第一涂层、第二涂层和导电层。具体地，第一涂层设置于正极集流体的至少一侧的表面，导电层设置于 第一涂层和第二涂层之间。其中第一涂层包括的第一活性材料和第二涂层包括的第二活性材料不同，也就是说，正极活性材料包括第一活性材料和第二活性材料两种不同的材料，这样，正极极片提供的正极活性材料可以兼具第一活性材料和第二活性材料的优点，从而有利于提高电池的整体性能。另一方面，由于第一活性材料和第二活性材料的材料性质差异，比如，电子电导率不同，若第一活性材料和第二活性材料直接接触，两种材料的性质差异会使两者之间互相影响，两种活性材料的性能降低而影响电池的性能。因此利用导电层将第一涂层和第二涂层隔开，避免第一活性材料和第二活性材料直接接触，同时电连接第一活性材料和第二活性材料。也就是说，导电层的设置既避免第一活性材料和第二活性材料直接接触，又能够保证第一活性材料和第二活性材料之间的电连接，使得第一活性材料和第二活性材料能够发挥各自的优点，使得电池的整体性能有所提升。
附图说明
为了更清楚地说明本申请实施例的技术方案，下面将对本申请实施例中所需要使用的附图作简单地介绍，显而易见地，下面所描述的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据附图获得其他的附图。
图1为本申请一实施例的正极极片的示意图；
图2为本申请一实施例的正极极片的示意图；
图3为本申请一实施例的正极极片的制备方法的示意图；
图4是本申请一实施例公开的一种电池单体的示意图；
图5是本申请一实施例公开的一种电池单体的分解结构示意图；
图6是本申请一实施例公开的一种电池的分解结构示意图；
图7是本申请一实施例公开的一种用电装置的示意图。
在附图中，附图并未按照实际的比例绘制。
具体实施方式中的附图标号如下：
正极极片1，正极集流体10，第一涂层11，第二涂层12，导电层13，电池10，箱体11，电池单体20，壳体21，电极组件22，盖板23。
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正极极片及其制备方法、电池单体、电池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。
在本申请的描述中，需要说明的是，除非另有说明，“多个”的含义是两个以上；术语“上”、“下”、“左”、“右”、“内”、“外”等指示的方位或位置关系仅是为了便于描述本申请和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请的限制。此外，术语“第一”、“第二”、“第三”等仅用于描述目的，而不能理解为指示或暗示相对重要性。
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)。
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。
锂离子电池因其高能量密度、高电压、长寿命等特点被广泛应用于移动手机、电动车辆、储电站等领域。正极极片作为电池的组成部分，正极极片的性能对于电池的性能至关重要。
正极极片包括正极集流体和涂覆于正极集流体表面的正极活性材料，正极活性材料是影响电池性能的重要因素。为了提高电池的整体性能，比如使电池兼具好的循环性能和高的能量密度，在正极集流体表面会涂覆两种或更多种的正极活性材料，但不同种活性材料之间的电化学性能有所差异，比如，电子电导率不同，会导致不同种活性材料之间接触不良，影响正极活性材料整体的导电性能，从而影响电池的性能。
鉴于此，本申请实施例提供了一种正极极片，包括正极集流体、第一涂层、第二涂层和导电层。具体地，第一涂层设置于正极集流体的至少一侧的表面，导电层设置于第一涂层和第二涂层之间。其中第一涂层包括的第一活性材料和第二涂层包括的第二活性材料不同，也就是说，正极活性材料包括第一活性材料和第二活性材料两种不同的材料，这样，正极极片提供的正极活性材料可以兼具第一活性材料和第二活 性材料的优点，从而有利于提高电池的整体性能。另一方面，利用导电层将第一涂层和第二涂层隔开，避免第一活性材料和第二活性材料直接接触，同时电连接第一活性材料和第二活性材料。也就是说，导电层的设置既避免第一活性材料和第二活性材料直接接触，又能够保证第一活性材料和第二活性材料之间的电连接，使得第一活性材料和第二活性材料能够发挥各自的优点，使得电池的整体性能有所提升。
以下，具体介绍本申请的多个实施例。
[正极极片]
图1为本申请一实施例的正极极片的示意图。如图1所示，正极极片1包括正极集流体10，第一涂层11，第二涂层12和导电层13。
导电层13设置于第一涂层11和第二涂层12之间，第一涂层设置于正极集流体10的表面。比如，如图1所示，沿正极极片1的厚度方向(图1中的z方向)，正极集流体10、第一涂层11、导电层13、第二涂层12依次设置。
正极集流体10具有沿其厚度方向设置的两个表面，第一涂层11、导电层13和第二涂层12设置于正极集流体10的同一侧的表面。可选地，如图1所示，正极集流体10的两个表面均设置有第一涂层11、导电层13和第二涂层12。
图2为本申请一实施例的正极极片的示意图。在一些其它实施例中，如图2所示，正极集流体10的沿厚度方向相对的两个表面中的一个表面设置有第一涂层11、导电层13和第二涂层12。
第一涂层11包括第一活性材料，第二涂层12包括第二活性材料，第二活性材料与第一活性材料不同。
可选地，第一活性材料和第二活性材料的晶体结构不同，其中，晶体结构可以表示材料中的原子在空间的排列规律。例如，第一活性材料包括具有橄榄石结构的磷酸盐材料、具有尖晶石结构的材料，第二活性材料包括具有层状结构的过渡金属氧化物。具有橄榄石结构的材料可以包括多种材料，例如磷酸铁锂(LiFePO4)、磷酸锰铁锂(LiMnFePO4)。具有层状结构的过渡金属氧化物可以包括多种材料，例如LiMO2，M包括Co、Ni、Mn中的至少一种。
导电层13用于隔离第一活性材料和第二活性材料。通过设置导电层13，可以降低第一活性材料与第二活性材料接触的风险，从而可以降低因第一活性材料和第 二活性材料的性能的差异对电池单体的影响。同时导电层13可以实现第一活性材料和第二活性材料之间的电连接。
例如，第一活性材料为具有碳包覆层的磷酸铁锂，第二活性材料为三元材料。第一活性材料附着于或包覆第二活性材料表面可能会导致电子在第二活性材料的表面聚集，聚集的电子影响锂离子嵌入第二活性材料，从而影响电池单体的循环性能。通过设置导电层13，导电层13隔离了第一活性材料和第二活性材料，这样可以降低第一活性材料附着或包覆在第二活性材料的风险，改善由于第一活性材料和第二活性材料的电导率差异导致的电子在第二活性材料表面的聚集现象，从而有利于降低聚集的电子对锂离子嵌入第二活性材料的风险，有利于提高电池单体的循环性能。
电池单体的循环性能可以由容量保持率衡量，容量保持率为保留容量与首次放电容量的比值。保留容量可以指，电池单体在完成一定次数的充放电循环之后，电池单体的放电容量。首次放电容量，可以指，电池单体进行第一次充放电测试时，电池单体的放电容量。
可选地，正极集流体10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。
本申请实施例提供了一种正极极片1，包括正极集流体10，第一涂层11，第二涂层12和导电层13。其中第一涂层11包括的第一活性材料和第二涂层12包括的第二活性材料不同，也就是说，正极活性材料包括第一活性材料和第二活性材料两种不同的材料，这样，正极极片1提供的正极活性材料可以兼具第一活性材料和第二活性材料的优点，从而有利于提高电池的整体性能。另一方面，利用导电层13将第一涂层11和第二涂层12隔开，避免第一活性材料和第二活性材料直接接触，同时电连接第一活性材料和第二活性材料。也就是说，导电层13的设置既避免第一活性材料和第二活性材料直接接触，又能够保证第一活性材料和第二活性材料之间的电连接，使得第一活性材料和第二活性材料能够发挥各自的优点，使得电池的整体性能有所提升。
可选地，在一些实施例中，第一活性材料包括橄榄石结构磷酸盐材料、尖 晶石材料中的至少一种。
橄榄石结构为材料的一种晶体结构，具有橄榄石结构的材料具有较高的稳定性，在应用于电池单体时，可以降低电池单体在高温等条件下发生起火、爆炸的风险，有利于提高电池单体的可靠性。橄榄石结构磷酸盐具有较高的理论比容量、较好的循环稳定性、低成本和环境友好等优点。尖晶石是镁铝氧化物组成的矿物，具有四面体晶形和八面体晶形，比如，尖晶石型锰酸锂材料具有比容量较高、成本低廉、环境污染小等突出特点。橄榄石结构磷酸盐材料、尖晶石材料用作第一活性材料，有利于提高电池的性能。
可选地，橄榄石结构磷酸盐材料包括LiaFebM1-bP1-mO4-n，其中，M包括除Fe外的其它金属元素中的至少一种，其中，0≤a≤1.1，0.3≤b≤1，0≤m≤0.1，0≤n≤0.1，可选地，M包括Mn、Al、Cu、Mg、Zn、Ni、Ti、V、Zr、Co、Ga、Sn、Sb、Nb和Ge中的至少一种，可选地，橄榄石结构磷酸盐材料包括LiFePO4、LiMnFePO4中的至少一种。
应理解，电池在充放电过程中会伴随锂的脱嵌及消耗，电池在放电到不同状态时锂的摩尔含量不同，以上对式LiaFebM1-bP1-mO4-n中的a的范围限定包括了电池不同充放电状态下锂的摩尔含量(通常电池电压在2V～5V之间)。
应理解，上述的LiFePO4、LiMnFePO4仅为本申请实施例中用做第一活性材料的物质的一个示例性说明，不构成对本申请的第一活性材料的限定。
LiFePO4具有循环寿命长、热稳定性好、能量密度高等优点；LiMnFePO4同样具有循环寿命长、热稳定性好等优点。LiFePO4、LiMnFePO4用作第一活性材料，可以提高电池的循环性能、能量密度和安全性。
可选地，尖晶石材料包括LiNicMn2-cO4，其中0≤c＜2，可选地，尖晶石材料包括锰酸锂(LiMn2O4)。
应理解，上述的LiMn2O4仅为本申请实施例中用做第一活性材料的物质的一个示例性说明，不构成对本申请的第一活性材料的限定。
LiMn2O4用作正极活性材料具有价格低、电位高、环境友好、安全性能高、倍率性能好等优点。
可选地，在一些实施例中，第二活性材料包括层状过渡金属氧化物。
层状过渡金属氧化物是一类具有多层(一般为二维)结构的氧化物，是基于过渡金属阳离子与晶格氧阴离子氧化还原反应获得的，具有高能量和高功率密度。层状过渡金属氧化物用作第二活性材料可以提高电池的能量密度。
可选地，层状过渡金属氧化物包括LiCoO2、LiMnO2、LiNiO2、Lia’NixCoyM1 1-x-yO2+d、zLi2MnO3·(1-z)LiM2O2中的至少一种，其中，M1包括Mn、Zr、Al、B、Ta、Mo、W、Nb、Sb、La中的至少一种，M2包括Co、Ni、Mn中的至少一种，0.5≤x≤1.0，0≤y＜0.5，x+y＜1，0.2≤a’＜1.2，-0.02≤d<0.02，0＜z＜1，可选地，所述层状过渡金属氧化物包括Li(Ni0.6Co0.2Mn0.2)1.15O2、Li(Ni0.5Co0.2Mn0.3)1.07O2中的至少一种。
镍钴锰酸锂(NCM)用作正极活性材料具有能量密度高、电压平台高、热稳定性好、循环性能好等优点。
应理解，上述的NCM仅为本申请实施例中用做第二活性材料的物质的一个示例性说明，不构成对本申请的第二活性材料的限定。
比如，第二活性材料可以包括三元材料、富锂锰基材料、无序岩盐相结构材料。“三元材料”是指由三种化学成分(元素)，组分(单质及化合物)组成的材料整体，比如用作电池正极活性材料的三元材料通常是以镍盐、钴盐、锰盐/铝盐为原料合成的含有镍钴锰(或镍钴铝)三种元素的材料，三元材料中镍钴锰(或镍钴铝)的比例可以根据实际需要调整，具有能量密度高、循环性能好等优点。三元材料、富锂锰基材料、无序岩盐相结构材料用作第二活性材料，可以提升电池的性能。
可选地，在一些实施例中，导电层13包括导电剂和粘结剂。
导电剂在活性材料之间起到收集微电流的作用，以减小电极的接触电阻加速电子的移动速率，同时也能有效地提高金属离子在电极材料中的迁移速率，从而提高电极的充放电效率。粘结剂可以使活性材料与导电剂之间粘结，增强活性材料与导电剂之间的电接触，还可以稳定正极极片的结构。
可选地，导电层13中不包括活性材料，仅包括导电剂和粘结剂。
可选地，导电层13为具有导电剂和粘结剂的多孔薄膜。
可选地，导电层13与第一涂层11和第二涂层12之间可粘结，可以降低正极极片1发生变形、打皱的风险。
可选地，在一些实施例中，导电剂包括导电炭黑、超导碳、碳点、科琴黑和碳纳米管中的至少一种。
由于碳结构的独特组成成分，碳材料导电剂具备良好的导电性能。比如，导电炭黑具有低电阻属性和高导电性能，粒径小，比表面积大且粗糙，结构高，表面洁净(化合物少)等优点；科琴黑具有独特的支链状形态，因而导电性高；碳纳米管中碳原子采取SP2杂化，因而具有高模量和高强度，碳纳米管还具有良好的柔韧性、可拉伸性和导电性能。导电炭黑、超导碳、碳点、科琴黑和碳纳米管作为导电剂可以提升电池的导电性能。
可选地，在一些实施例中，粘结剂包括聚偏氟乙烯、苯乙烯聚丁橡胶、聚四氟乙烯、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、偏二氟乙烯-六氟丙烯共聚物、偏二氟乙烯-三氯乙烯共聚物及含氟丙烯酸酯树脂、聚丙烯腈、聚乙烯吡咯烷酮、聚醋酸乙烯酯、聚乙烯-共-醋酸乙烯酯、聚环氧乙烷、聚芳酯中的至少一种。
可选地，在一些实施例中，如图1和图2所示，导电层13的厚度d3为1μm～15μm，可选地，导电层13的厚度d3为5μm～10μm。
具体地，导电层13的厚度d3可以为1μm、2μm、3μm、4μm、5μm、6μm、7μm、8μm、9μm、10μm、11μm、12μm、13μm、14μm、15μm，或是以上任意两个数值之间的数值。
一方面，导电层13的厚度不宜过小，这样可以使得导电层13能够有效隔离第一活性材料与第二活性材料，另一方面，导电层13的厚度不宜过大，这样可以保证正极极片中活性材料含量不会过少，以保证电池的能量密度。
可选地，在一些实施例中，如图1和图2所示，第一涂层11的厚度d1为40μm～160μm，可选地，第一涂层11的厚度d1为70μm～140μm。
具体地，第一涂层11的厚度d1可以为40μm、50μm、60μm、70μm、80μm、90μm、100μm、110μm、120μm、130μm、140μm、150μm、160μm，或是以上任意两个数值之间的数值。
第一涂层11的厚度不宜过大，以减少第一活性材料的浪费和减小电池的总体积，降低生产成本，第一涂层厚度也不宜过小，以保证正极极片中的第一活性材料的含量不会过少，有利于电池性能的提升。
可选地，在一些实施例中，如图1和图2所示，第二涂层12的厚度d2为40μm～80μm，可选地，第二涂层12的厚度d2为40μm～60μm。
具体地，第二涂层12的厚度d2可以为40μm、50μm、60μm、70μm、80μm，或是以上任意两个数值之间的数值。
第二涂层厚度不宜过大，以减少第二活性材料的浪费和减小电池的总体积，降低生产成本，第二涂层厚度也不宜过小，以保证正极极片中的第二活性材料的含量不会过少，有利于电池性能的提升。
可选地，在一些实施例中，基于导电层的总重量计，导电层中的粘结剂的重量百分含量为1wt％～10wt％，可选地，为3wt％～7wt％。
具体地，导电层中的粘结剂的重量百分含量可以为1wt％、2wt％、3wt％、4wt％、5wt％、6wt％、7wt％、8wt％、9wt％、10wt％，或是以上任意两个数值之间的数值。
可选地，在一些实施例中，基于导电层的总重量计，导电层中的导电剂的重量百分含量为90wt％～99wt％，可选地，为93wt％～97wt％。
具体地，导电层中的导电剂的重量百分含量为90wt％、91wt％、92wt％、93wt％、94wt％、95wt％、96wt％、97wt％、98wt％、99wt％，或是以上任意两个数值之间的数值。
导电层中的导电剂在活性材料之间起到收集微电流的作用，以减小电极的接触电阻加速电子的移动速率，同时也能有效地提高金属离子在电极材料中的迁移速率，从而提高电极的充放电效率。导电剂的含量太少，会减少正极极片中的电子导通通道，使得正极活性物质的利用率低，从而降低电池的循环性能和能量密度。因此设置导电层中的导电剂的含量为90wt％～99wt％，有利于提升电池的整体性能。
上述技术方案中，通过设置导电层13中的导电剂和粘接剂的重量含量在适宜范围内，使得导电层13可以有效发挥其隔离和电连接第一活性材料和第二活性材料 的作用，以提升电池的整体性能。
可选地，在一些实施例中，基于第一涂层的总重量计，第一活性材料的重量百分含量为90wt％～98wt％，可选地，为96wt％～97wt％。
具体地，第一涂层中的第一活性材料的重量百分含量可以为90wt％、91wt％、92wt％、93wt％、94wt％、95wt％、96wt％、97wt％、98wt％，或是以上任意两个数值之间的数值。
可选地，在一些实施例中，基于第一涂层的总重量计，第一涂层中的导电剂的重量百分含量为0.1wt％～1wt％，可选地，为0.4wt％～0.6wt％。
具体地，第一涂层中的导电剂的重量百分含量可以为0.1wt％、0.2wt％、0.3wt％、0.4wt％、0.5wt％、0.6wt％、0.7wt％、0.8wt％、0.9wt％、1wt％，或是以上任意两个数值之间的数值。
可选地，在一些实施例中，基于第一涂层的总重量计，第一涂层中的粘结剂的重量百分含量为1wt％～2wt％，可选地，为1.2wt％～1.4wt％。
具体地，第一涂层中的粘结剂的重量百分含量可以为1wt％、1.1wt％、1.2wt％、1.3wt％、1.4wt％、1.5wt％、1.6wt％、1.7wt％、1.8wt％、1.9wt％、2wt％，或是以上任意两个数值之间的数值。
上述技术方案中，通过设置第一涂层11中的第一活性材料、导电剂和粘接剂的重量含量在适宜范围内，使得第一活性材料能够有效发挥作用。
可选地，在一些实施例中，基于第二涂层的总重量计，第二活性材料的重量百分含量为90wt％～98wt％，可选为96wt％～97wt％。
具体地，第二涂层中的第二活性材料的重量百分含量可以为90wt％、91wt％、92wt％、93wt％、94wt％、95wt％、96wt％、97wt％、98wt％，或是以上任意两个数值之间的数值。
可选地，在一些实施例中，基于第二涂层的总重量计，第二涂层中的导电剂的重量百分含量为0.1wt％～1wt％，可选地，为0.4wt％～0.6wt％。
具体地，第二涂层中的导电剂的重量百分含量可以为0.1wt％、0.2wt％、0.3wt％、0.4wt％、0.5wt％、0.6wt％、0.7wt％、0.8wt％、0.9wt％、1wt％，或是以上任 意两个数值之间的数值。
可选地，在一些实施例中，基于第二涂层的总重量计，第二涂层中的粘结剂的重量百分含量为1wt％～2wt％，可选地，为1.2wt％～1.4wt％。
具体地，第一涂层中的粘结剂的重量百分含量可以为1wt％、1.1wt％、1.2wt％、1.3wt％、1.4wt％、1.5wt％、1.6wt％、1.7wt％、1.8wt％、1.9wt％、2wt％，或是以上任意两个数值之间的数值。
上述技术方案中，通过设置第二涂层12中的第二活性材料、导电剂和粘接剂的重量含量在适宜范围内，使得第二活性材料能够有效发挥作用。
[正极极片的制备方法]
图3为本申请一实施例的正极极片的制备方法。如图3所示，方法300包括以下步骤。
步骤310，提供正极集流体，在正极集流体上设置第一涂层、第二涂层和导电层。
其中，第一涂层设置于正极集流体的至少一侧的表面，导电层设置于第一涂层和第二涂层之间，第一涂层包括第一活性材料，第二涂层包括第二活性材料，第二活性材料与第一活性材料不同。
通过上述方法制备的正极极片，在应用于电池时，有利于提高电池的性能。
[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膜层，所述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，负极活性材料可采用本领域公知的用于电池的负极活性材料。作为示例，负极活性材料可包括以下材料中的至少一种：人造石墨、天然石墨、软炭、硬炭、硅基材料、锡基材料和钛酸锂等。所述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。所述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，负极膜层还可选地包括粘结剂。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，负极膜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，负极膜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，电池单体中还包括隔离膜。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。
以下参照附图对本申请电池单体、电池和用电装置进行说明。
本申请实施例还提供一种电池单体。电池单体包括上述实施例中的正极极片、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。
应理解，本申请所述“嵌入”过程指活性离子由于电化学反应在正极活性材料或负极活性材料中嵌入的过程，本申请所述“脱出”、“脱嵌”过程指活性离子由于电化学反应在正极活性材料或负极活性材料中脱出的过程。
在一些实施方式中，电池单体可包括外包装。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，电池单体的外包装可以是硬壳，例如硬塑料壳、铝壳、钢壳等。电池单体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。
本申请对电池单体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4是作为一个示例的方形结构的电池单体20。
在一些实施方式中，参照图5，外包装可包括壳体21和盖板23。其中，壳体21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21具有与容纳腔连通的开口，盖板23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22。电极组件22封装于容纳腔内。电解液浸润于电极组件22中。电池单体20所含电极组件22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，电池10可以包括多个电池单体20。例如，如图6所示，为本申请一个实施例的一种电池10的结构示意图，电池10可以包括多个电池单体20。电池10还可以包括箱体11，箱体11内部为中空结构，多个电池单体20容纳于箱体11内。例如，多个电池单体20相互并联或串联或混联组合后置于箱体11内。
可选地，电池10还可以包括其他结构，在此不再一一赘述。例如，该电池10还可以包括汇流部件，汇流部件用于实现多个电池单体20之间的电连接，例如并联或串联或混联。具体地，汇流部件可通过连接电池单体20的电极端子实现电池单体20之间的电连接。进一步地，汇流部件可通过焊接固定于电池单体20的电极端子。多个电池单体20的电能可进一步通过导电机构穿过箱体11而引出。可选地，导电机构也可属于汇流部件。
根据不同的电力需求，电池单体20的数量可以设置为任意数值。多个电池单体20可通过串联、并联或混联的方式连接以实现较大的容量或功率。由于每个电池 10中包括的电池单体20的数量可能较多，为了便于安装，可以将电池单体20分组设置，每组电池单体20组成电池模块。电池模块中包括的电池单体20的数量不限，可以根据需求设置。电池可以包括多个电池模块，这些电池模块可通过串联、并联或混联的方式进行连接。
另外，本申请还提供一种用电装置，该用电装置包括本申请提供的电池单体、电池模块或电池中的至少一种。电池单体、电池模块或电池可以用作该用电装置的电源，也可以用作该用电装置的能量存储单元。该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。
作为该用电装置，可以根据其使用需求来选择电池单体、电池模块或电池。
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电池单体的高功率和高能量密度的需求，可以采用电池或电池模块。
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，可以采用电池单体作为电源。
[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。
(1)正极极片的制备
正极极片1：将磷酸铁锂(LiFePO4)、导电碳黑、碳纳米管(CNT)、聚偏二氟乙烯(PVDF)按照重量比为97.6:0.6:0.4:1.4溶于溶剂N-甲基吡咯烷酮(NMP)，经过搅拌混合均匀后制成第一涂层。
将镍钴锰酸锂(NCM622)、导电碳黑、CNT、PVDF按照重量比为97.6:0.6:0.4:1.4溶于溶剂NMP，经过搅拌混合均匀后制成第二涂层。
将粘结剂羧甲基纤维素(CMC)、导电剂导电碳黑按照重量比为3:97溶于溶剂去离子水，经过搅拌混合均匀后制成导电层。
使用挤压涂布将上述第一涂层、第二涂层、导电层按照本申请实施例中的图1或图2所示的正极极片的结构，同时或者分步涂布到正极集流体上(比如，可以用LOM挤压涂布机将第一涂层、第二涂层、导电层同时涂布到正极集流体上)，制得正极极片1。其中，第一涂层的厚度为130μm，第二涂层的厚度为50μm，导电层的厚度为1μm。
正极极片2：正极极片2相对于正极极片1，不同的是导电层的厚度为5μm，制得正极极片2。
正极极片3：正极极片3相对于正极极片1，不同的是导电层的厚度为10μm，制得正极极片3。
正极极片4：正极极片4相对于正极极片1，不同的是导电层的厚度为15μm，制得正极极片4。
正极极片5：正极极片5相对于正极极片2，不同的是第一涂层的厚度为40μm，制得正极极片5。
正极极片6：正极极片6相对于正极极片2，不同的是第一涂层的厚度为70μm，制得正极极片6。
正极极片7：正极极片7相对于正极极片2，不同的是第一涂层的厚度为140μm，制得正极极片7。
正极极片8：正极极片8相对于正极极片2，不同的是第一涂层的厚度为160μm，制得正极极片8。
正极极片9：正极极片9相对于正极极片2，不同的是第二涂层的厚度为40μm，制得正极极片9。
正极极片10：正极极片10相对于正极极片2，不同的是第二涂层的厚度为60μm，制得正极极片10。
正极极片11：正极极片11相对于正极极片2，不同的是第二涂层的厚度为80μm，制得正极极片11。
正极极片12：正极极片12相对于正极极片2，不同的是将磷酸锰铁锂(LiMnFePO4)、导电碳黑、CNT、PVDF按照重量比为97.6:0.6:0.4:1.4溶于溶剂NMP，经过搅拌混合均匀后制成第一涂层，第一涂层的厚度为130μm，制得正极极片12。
正极极片13：正极极片13相对于正极极片2，不同的是将LiCoO2、导电碳黑、CNT、PVDF按照重量比为97.6:0.6:0.4:1.4溶于溶剂NMP，经过搅拌混合均匀后制成第二涂层，第二涂层的厚度为50μm，制得正极极片13。
正极极片14：正极极片14相对于正极极片2，不同的是导电层的厚度为20μm，制得正极极片14。
正极极片15：正极极片15相对于正极极片2，不同的是第一涂层的厚度为30μm，制得正极极片15。
正极极片16：正极极片16相对于正极极片2，不同的是第一涂层的厚度为170μm，制得正极极片16。
正极极片17：正极极片17相对于正极极片2，不同的是第二涂层的厚度为30μm，制得正极极片17。
正极极片18：正极极片18相对于正极极片2，不同的是第二涂层的厚度为90μm，制得正极极片18。
正极极片19：正极极片19相对于正极极片2，不同的是导电层中粘结剂CMC和导电剂导电碳黑的重量比为10:90，制得正极极片19。
正极极片20：正极极片20相对于正极极片2，不同的是导电层中粘结剂CMC和导电剂导电碳黑的重量比为7:93，制得正极极片20。
正极极片21：正极极片21相对于正极极片2，不同的是导电层中粘结剂CMC和导电剂导电碳黑的重量比为1:99，制得正极极片21。
正极极片22：正极极片22相对于正极极片2，不同的是未设置导电层，制得正极极片22。
(2)负极极片的制备
将人造石墨、导电炭黑、丁苯橡胶(SBR)、CMC按照重量比为 95.5:1.2:1.3:1.5溶于溶剂去离子水中，均匀混合后制备成负极浆料；然后将负极浆料均匀涂布在负极集流体上，烘干后得到负极膜片，再经过冷压、分切得到负极极片。
(3)电解液的制备：在含水量<10ppm的氩气气氛手套箱中，将充分干燥的锂盐(LiPF6)溶解在体积比为20:20:60的碳酸乙烯酯(EC)、碳酸甲乙酯(EMC)和碳酸二乙酯(DEC)的混合溶剂中，然后加入添加剂碳酸亚乙烯酯(VC)，混合均匀，获得电解液。其中，锂盐的浓度为1mol/L。
(4)隔离膜的制备：以常规的聚丙烯膜作为隔离膜。
(5)锂离子电池的组装：将正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正极极片和负极极片之间起到隔离的作用，然后卷绕得到电极组件；将电极组件置于电池壳体中，干燥后注入电解液，再经过化成、静置等工艺制得锂离子电池。
实施例1：将正极极片1、隔离膜、负极极片、电解液按照上述方法组装得到的锂离子电池为实施例1。
实施例2：将正极极片2、隔离膜、负极极片、电解液按照上述方法组装得到的锂离子电池为实施例2。
实施例3：将正极极片3、隔离膜、负极极片、电解液按照上述方法组装得到的锂离子电池为实施例3。
实施例4：将正极极片4、隔离膜、负极极片、电解液按照上述方法组装得到的锂离子电池为实施例4。
实施例5：将正极极片5、隔离膜、负极极片、电解液按照上述方法组装得到的锂离子电池为实施例5。
实施例6：将正极极片6、隔离膜、负极极片、电解液按照上述方法组装得到的锂离子电池为实施例6。
实施例7：将正极极片7、隔离膜、负极极片、电解液按照上述方法组装得到的锂离子电池为实施例7。
实施例8：将正极极片8、隔离膜、负极极片、电解液按照上述方法组装得到的锂离子电池为实施例8。
实施例9：将正极极片9、隔离膜、负极极片、电解液按照上述方法组装得到的锂离子电池为实施例9。
实施例10：将正极极片10、隔离膜、负极极片、电解液按照上述方法组装得到的锂离子电池为实施例10。
实施例11：将正极极片11、隔离膜、负极极片、电解液按照上述方法组装得到的锂离子电池为实施例11。
实施例12：将正极极片12、隔离膜、负极极片、电解液按照上述方法组装得到的锂离子电池为实施例12。
实施例13：将正极极片13、隔离膜、负极极片、电解液按照上述方法组装得到的锂离子电池为实施例13。
实施例14：将正极极片14、隔离膜、负极极片、电解液按照上述方法组装得到的锂离子电池为实施例14。
实施例15：将正极极片15、隔离膜、负极极片、电解液按照上述方法组装得到的锂离子电池为实施例15。
实施例16：将正极极片16、隔离膜、负极极片、电解液按照上述方法组装得到的锂离子电池为实施例16。
实施例17：将正极极片17、隔离膜、负极极片、电解液按照上述方法组装得到的锂离子电池为实施例17。
实施例18：将正极极片18、隔离膜、负极极片、电解液按照上述方法组装得到的锂离子电池为实施例18。
实施例19：将正极极片19、隔离膜、负极极片、电解液按照上述方法组装得到的锂离子电池为实施例19。
实施例20：将正极极片20、隔离膜、负极极片、电解液按照上述方法组装得到的锂离子电池为实施例20。
实施例21：将正极极片21、隔离膜、负极极片、电解液按照上述方法组装得到的锂离子电池为实施例21。
对比例1：将正极极片22、隔离膜、负极极片、电解液按照上述方法组装得到的锂离子电池为对比例1。
不同实施例的产品参数详见表1。
表1：对比例及不同实施例的产品参数
接下来，对相关参数的测试过程进行说明。
1、循环性能测试
在25/45℃下，先以1C的恒定电流对电池单体充电至4.3V，进一步以4.3V恒定电压充电至电流为0.05C，然后以1C的恒定电流将电池放电至3V，此为一个充放电循环过程，此次的放电容量为第1次循环的放电容量。电池按上述方式进行多次循环充放电测试，检测得到第200次循环的放电容量，并通过下式计算得出电池单体的循环后的容量保持率。电池200次循环后的容量保持率(％)＝[第200次循环的放电容量/第 1次循环的放电容量]×100％。
2、能量密度的测试
室温(25℃±2℃)环境下，以恒流放电的形式(1/3C倍率)放电至下限电压后，静置30min，然后以恒流恒压充电方式(恒流1/3C，恒压充电至1/20C)充电上限截止电压，静置30min，计放电能量E(以Wh计)，重复3次，取3次放电能量E的平均值记为E0，除以硬壳电池单体的体积V，则体积能量密度(以Wh/L计)＝E0/V。
按照上述方法分别对制备得到的对比例1、实施例1-21进行电池性能测试，结果详见表2。
表2：对比例及不同实施例的性能测试结果
从对比例1和实施例1-4的结果比较可知，在第一涂层和第二涂层之间设置导电层连接第一活性材料和第二活性材料，可以提升电池的循环性能。
从实施例1-4、14的结果比较可知，导电层厚度需设置在适宜范围内，导电层厚度过大，会减小活性材料层中活性材料的占比，会降低电池的能量密度。
从实施例2、19-21的结果比较可知，在导电层厚度一定的情况下，在一定范围内，导电层中的导电剂的含量越高，电池的循环性能越好，能量密度越高。
虽然已经参考优选实施例对本申请进行了描述，但在不脱离本申请的范围的情况下，可以对其进行各种改进并且可以用等效物替换其中的部件。尤其是，只要不存在结构冲突，各个实施例中所提到的各项技术特征均可以任意方式组合起来。本申请并不局限于文中公开的特定实施例，而是包括落入权利要求的范围内的所有技术方案。

Claims (24)

  1. 一种正极极片，包括：
    正极集流体；
    第一涂层，所述第一涂层设置于所述正极集流体的至少一侧的表面，所述第一涂层包括第一活性材料；
    第二涂层，所述第二涂层包括第二活性材料，所述第二活性材料与所述第一活性材料不同；
    导电层，所述导电层设置于所述第一涂层和所述第二涂层之间，用于隔离所述第一涂层和所述第二涂层。
  2. 根据权利要求1所述的正极极片，其中，所述第一活性材料包括橄榄石结构磷酸盐材料、尖晶石材料中的至少一种。
  3. 根据权利要求2所述的正极极片，其中，所述橄榄石结构磷酸盐材料包括LiaFebM1-bP1-mO4-n，其中，M包括除Fe外的其它金属元素中的至少一种，其中，0≤a≤1.1，0.3≤b≤1，0≤m≤0.1，0≤n≤0.1，可选地，M包括Mn、Al、Cu、Mg、Zn、Ni、Ti、V、Zr、Co、Ga、Sn、Sb、Nb和Ge中的至少一种，可选地，所述橄榄石结构磷酸盐材料包括磷酸铁锂、磷酸锰铁锂中的至少一种。
  4. 根据权利要求2或3所述的正极极片，其中，所述尖晶石材料包括LiNicMn2-cO4，其中0≤c＜2，可选地，所述尖晶石材料包括锰酸锂。
  5. 根据权利要求1至4中任一项所述的正极极片，其中，所述第二活性材料包括层状过渡金属氧化物。
  6. 根据权利要求5所述的正极极片，其中，所述层状过渡金属氧化物包括LiCoO2、LiMnO2、LiNiO2、Lia’NixCoyM1 1-x-yO2+d、zLi2MnO3·(1-z)LiM2O2中的至少一种，其中，M1包括Mn、Zr、Al、B、Ta、Mo、W、Nb、Sb、La中的至少一种，M2包括Co、Ni、Mn中的至少一种，0.5≤x≤1.0，0≤y＜0.5，x+y＜1，0.2≤a’＜1.2，-0.02≤d<0.02，0＜z＜1，可选地，所述层状过渡金属氧化物包括Li(Ni0.6Co0.2Mn0.2)1.15O2、Li(Ni0.5Co0.2Mn0.3)1.07O2中的至少一种。
  7. 根据权利要求1至6中任一项所述的正极极片，其中，所述导电层包括导电剂和粘结剂。
  8. 根据权利要求7所述的正极极片，其中，所述导电剂包括导电炭黑、超导碳、碳点、科琴黑和碳纳米管中的至少一种。
  9. 根据权利要求7或8所述的正极极片，其中，所述粘结剂包括聚偏氟乙烯、苯乙烯聚丁橡胶、聚四氟乙烯、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、偏二氟乙烯-六氟丙烯共聚物、偏二氟乙烯-三氯乙烯共聚物及含氟丙烯酸酯树脂、聚丙烯腈、聚乙烯吡咯烷酮、聚醋酸乙烯酯、聚乙烯-共-醋酸乙烯酯、聚环氧乙烷、聚芳酯中的至少一种。
  10. 根据权利要求1至9中任一项所述的正极极片，其中，所述导电层的厚度为1μm～15μm，可选地，所述导电层的厚度为5μm～10μm。
  11. 根据权利要求1至10中任一项所述的正极极片，其中，所述第一涂层的厚度为40μm～160μm，可选地，所述第一涂层的厚度为70μm～140μm。
  12. 根据权利要求1至11中任一项所述的正极极片，其中，所述第二涂层的厚度为40μm～80μm，可选地，所述第二涂层的厚度为40μm～60μm。
  13. 根据权利要求1至12中任一项所述的正极极片，其中，基于所述导电层的总重量计，所述导电层中的粘结剂的重量百分含量为1wt％～10wt％，可选地，为3wt％～7wt％。
  14. 根据权利要求1至13中任一项所述的正极极片，其中，基于所述导电层的总重量计，所述导电层中的导电剂的重量百分含量为90wt％～99wt％，可选地，为93wt％～97wt％。
  15. 根据权利要求1至14中任一项所述的正极极片，其中，基于所述第一涂层的总重量计，所述第一活性材料的重量百分含量为90wt％～98wt％，可选地，为96wt％～97wt％。
  16. 根据权利要求1至15中任一项所述的正极极片，其中，基于所述第一涂层的总重量计，所述第一涂层中的导电剂的重量百分含量为0.1wt％～1wt％，可选地，为0.4wt％～0.6wt％。
  17. 根据权利要求1至16中任一项所述的正极极片，其中，基于所述第一涂层的总重量计，所述第一涂层中的粘结剂的重量百分含量为1wt％～2wt％，可选地，为1.2wt％～1.4wt％。
  18. 根据权利要求1至17中任一项所述的正极极片，其中，基于所述第二涂层的总重量计，所述第二活性材料的重量百分含量为90wt％～98wt％，可选地，为96wt％～97wt％。
  19. 根据权利要求1至18中任一项所述的正极极片，其中，基于所述第二涂层的总重量计，所述第二涂层中的导电剂的重量百分含量为0.1wt％～1wt％，可选地，为0.4wt％～0.6wt％。
  20. 根据权利要求1至19中任一项所述的正极极片，其中，基于所述第二涂层的总重量计，所述第二涂层中的粘结剂的重量百分含量为1wt％～2wt％，可选地，为1.2wt％～1.4wt％。
  21. 一种正极极片的制备方法，包括：
    提供正极集流体，在所述正极集流体上设置第一涂层、第二涂层和导电层；
    其中，所述第一涂层设置于所述正极集流体的至少一侧的表面，所述导电层设置于所述第一涂层和所述第二涂层之间，所述第一涂层包括第一活性材料，所述第二涂层包括第二活性材料，所述第二活性材料与所述第一活性材料不同。
  22. 一种电池单体，包括根据权利要求1至20中任一项所述的正极极片。
  23. 一种电池，包括根据权利要求22所述的电池单体。
  24. 一种用电装置，包括根据权利要求23所述的电池。
PCT/CN2023/086699 2023-04-06 2023-04-06 正极极片及其制备方法、电池单体、电池和用电装置 Ceased WO2024207353A1 (zh)

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CN120565812A (zh) * 2025-06-13 2025-08-29 宁德时代新能源科技股份有限公司 电池单体、电池装置和用电装置

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