WO2026002189A1 - 电极极片、电池及用电设备 - Google Patents

电极极片、电池及用电设备

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Publication number
WO2026002189A1
WO2026002189A1 PCT/CN2025/104308 CN2025104308W WO2026002189A1 WO 2026002189 A1 WO2026002189 A1 WO 2026002189A1 CN 2025104308 W CN2025104308 W CN 2025104308W WO 2026002189 A1 WO2026002189 A1 WO 2026002189A1
Authority
WO
WIPO (PCT)
Prior art keywords
active material
material layer
electrode sheet
mass content
negative electrode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/CN2025/104308
Other languages
English (en)
French (fr)
Inventor
张辉
邢伟伟
陈广安
梁国俊
梁美浩
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BYD Co Ltd
Original Assignee
BYD Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by BYD Co Ltd filed Critical BYD Co Ltd
Publication of WO2026002189A1 publication Critical patent/WO2026002189A1/zh
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • 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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • This application relates to the field of batteries, specifically to electrode sheets, batteries, and electrical devices.
  • this application provides an electrode sheet, a battery, and an electrical device.
  • the electrode sheet is not prone to lithium plating, has high volumetric energy density and gravimetric energy density, and low manufacturing cost, which is beneficial to improving the electrochemical performance of the battery and its industrial application.
  • this application provides an electrode sheet, the electrode sheet comprising a current collector and an active material layer disposed on at least one side surface of the current collector, the active material layer comprising a first active material layer and a second active material layer disposed in the same layer as and connected to the first active material layer, the thickness of the second active material layer gradually decreasing along the direction from the first active material layer to the second active material layer, the first active material layer comprising a first active material, the second active material layer comprising a second active material, and the mass content of the first active material in the first active material layer being less than the mass content of the second active material in the second active material layer.
  • the second active material layer is disposed on one side of the first active material layer, or the second active material layer is disposed on opposite sides of the first active material layer.
  • the mass content of the first active material is 93%-97.2%.
  • the mass content of the second active material is 96.2%-98.5%.
  • the primary particle size D50 of the first active material is smaller than the primary particle size D50 of the second active material.
  • the mass content of the carbon coating layer of the first active material is greater than the mass content of the carbon coating layer of the second active material.
  • the primary particle size D50 of the first active material is 0.3 ⁇ m-9 ⁇ m.
  • the primary particle size D50 of the second active material is 0.7 ⁇ m-15 ⁇ m.
  • the carbon coating layer of the first active material has a mass content of 0.5%-2%.
  • the carbon coating layer of the second active material has a mass content of less than or equal to 0.5%.
  • the first active material layer further includes a first conductive agent and a first binder
  • the second active material layer further includes a second conductive agent and a second binder.
  • the mass content of the first conductive agent in the first active material layer is greater than the mass content of the second conductive agent in the second active material layer.
  • the mass content of the first adhesive in the first active material layer is greater than the mass content of the second adhesive in the second active material layer.
  • the mass content of the first conductive agent is 0.5%-2%, and the mass content of the first binder is 1%-3%.
  • the mass content of the second conductive agent is less than or equal to 1%, and the mass content of the second binder is 0.5%-2%.
  • the thickness of the first active material layer is 92 ⁇ m-300 ⁇ m, and the maximum thickness of the second active material layer is 92 ⁇ m-300 ⁇ m.
  • the size of the first active material layer is 80mm-1000mm along the direction from the second active material layer to the first active material layer.
  • the size of the second active material layer is 10mm-30mm.
  • the areal density of the electrode sheet is 150 g/ m2 - 600 g/ m2 .
  • the electrode sheet provided in this application has a low probability of lithium plating, high volumetric energy density and gravimetric energy density, which improves the cycle stability of the electrode sheet and helps to improve the battery life.
  • this application provides a battery comprising a positive electrode and a negative electrode, and a separator disposed between the positive electrode and the negative electrode, wherein the negative electrode comprises the electrode described in the first aspect.
  • the positive electrode includes the electrode described in the first aspect.
  • the battery provided in this application has excellent electrochemical performance, long service life, and strong product competitiveness.
  • this application provides an electrical device, which includes the battery described in the second aspect.
  • the electrical equipment provided in this application has excellent overall performance, high safety performance, and strong market competitiveness.
  • Figure 1 is a cross-sectional schematic diagram of an electrode sheet provided in one embodiment of this application.
  • Figure 2 is a cross-sectional schematic diagram of an electrode sheet provided in another embodiment of this application.
  • FIG. 3 is a cross-sectional schematic diagram of an electrode sheet provided in another embodiment of this application.
  • the electrode sheet 100 includes a current collector 10 and an active material layer 20 disposed on at least one side surface of the current collector 10.
  • the active material layer 20 includes a first active material layer 21 and a second active material layer 22 disposed in the same layer as and connected to the first active material layer 21.
  • the thickness of the second active material layer 22 gradually decreases along the direction from the first active material layer 21 to the second active material layer 22.
  • the first active material layer 21 includes a first active material
  • the second active material layer 22 includes a second active material.
  • the mass content of the first active material in the first active material layer 21 is less than the mass content of the second active material in the second active material layer 22.
  • the electrode sheet provided in this application controls the relationship between the mass content of the first active material in the first active material layer and the mass content of the second active material layer in the second active material layer, thereby increasing the number of ion insertion sites in the second active material layer, improving the capacity of the second active material layer, and thus improving the capacity, volumetric energy density and gravimetric energy density of the electrode sheet. It also reduces the probability of lithium plating during use, which is beneficial to improving the battery capacity, cycle stability and service life.
  • the thickness of the second active material layer gradually decreases along the direction from the first active material layer to the second active material layer (as indicated by the arrow in Figure 1).
  • This gradual decrease can be linear or non-linear, such as gradient decrease or parabolic decrease.
  • the region in the active material layer of the electrode sheet where the thickness gradually decreases is defined as the thinning region, and the region where the thickness remains constant is defined as the non-thinning region. Therefore, the first active material layer is the non-thinning region, and the second active material layer is the thinning region.
  • This application increases the capacity of the thinned region of the electrode sheet by increasing the content of the second active material in the thinning region, thereby increasing the capacity of the electrode sheet, mitigating lithium desorption, and improving the energy density of the electrode sheet.
  • the current collector in the electrode sheet converts chemical energy into electrical energy for output, thereby improving the conductivity of the electrode sheet.
  • the current collector can be a positive or negative current collector; when the electrode sheet is a positive electrode sheet, the current collector is a positive current collector; when the electrode sheet is a negative electrode sheet, the current collector is a negative current collector.
  • the positive current collector may be, but is not limited to, at least one of copper, aluminum, nickel, and stainless steel;
  • the negative current collector may be, but is not limited to, at least one of copper, aluminum, nickel, and stainless steel.
  • the current collector when the current collector is a positive current collector, the electrode sheet is a positive electrode sheet, and the current collector can be aluminum foil.
  • the current collector when the current collector is a negative current collector, the electrode sheet is a negative electrode sheet, and the current collector can be copper foil.
  • the active material layer completely covers the surface of the current collector; that is, the orthographic projection of the active material layer onto the surface of the current collector completely covers that surface.
  • Figure 2 which is a cross-sectional schematic diagram of an electrode sheet provided in another embodiment of this application, in the electrode sheet 100, there is an area on the surface of the current collector 10 that is not covered by the active material layer 20. This area in the current collector 10 that is not covered by the active material layer 20 serves as a tab 11. One end of the tab 11 is connected to the second active material layer 22 (thinned area), and the other end of the tab 11 can be connected to an external device for charge-discharge cycle processing.
  • the second active material layer is disposed on one side of the first active material layer.
  • the second active material layer can be disposed between the first active material layer and the tab.
  • the second active material layer is disposed on opposite sides of the first active material layer.
  • the second active material layer can be disposed between the first active material layer and the tab.
  • the electrode plate 100 includes a current collector 10 and an active material layer 20 disposed on one side surface of the current collector 10.
  • the active material layer 20 includes a first active material layer 21 and a second active material layer 22, which are disposed on the same side surface of the current collector 10.
  • FIG3 which is a cross-sectional schematic diagram of an electrode plate provided in another embodiment of this application, the electrode plate 100 includes a current collector 10 and active material layers 20 disposed on opposite sides of the current collector 10, which can further improve the energy density of the electrode plate and reduce the probability of lithium plating.
  • the first active material can be a positive electrode active material or a negative electrode active material.
  • the first active material is a positive electrode active material; when the electrode plate is a negative electrode plate, the first active material is a negative electrode active material.
  • the positive electrode active material may include, but is not limited to, at least one of lithium cobalt oxide, nickel cobalt manganese, nickel cobalt aluminum, nickel cobalt manganese aluminum, lithium iron phosphate, lithium manganese phosphate, lithium vanadium phosphate, lithium manganese oxide, and lithium-rich manganese-based materials;
  • the negative electrode active material may include, but is not limited to, at least one of artificial graphite, natural graphite, hard carbon, soft carbon, and graphene.
  • the first active material when the first active material is a positive electrode active material, the first active material may be lithium iron phosphate.
  • the first active material when the first active material is a negative electrode active material, the first active material may be artificial graphite.
  • the second active material layer includes a second active material, which can be a positive electrode active material or a negative electrode active material.
  • the second active material is a positive electrode active material
  • the second active material is a negative electrode active material, which can improve the conductivity and energy density of the electrode sheet.
  • the positive electrode active material may include, but is not limited to, at least one of lithium cobalt oxide, nickel cobalt manganese, nickel cobalt aluminum, nickel cobalt manganese aluminum, lithium iron phosphate, lithium manganese phosphate, lithium vanadium phosphate, lithium manganese oxide, and lithium-rich manganese-based materials;
  • the negative electrode active material may include, but is not limited to, at least one of artificial graphite, natural graphite, hard carbon, soft carbon, and graphene.
  • the second active material when the second active material is a positive electrode active material, the second active material can be lithium iron phosphate.
  • the second active material when the second active material is a negative electrode active material, the second active material can be artificial graphite.
  • the mass content of the first active material in the first active material layer is 93%-97.2%, which can improve the energy density and conductivity of the electrode sheet.
  • the mass content of the first active material in the first active material layer can be, but is not limited to, 93%, 94%, 95%, 96%, 9.65%, or 97.2%.
  • the mass content of the first active material in the first active material layer can be 93%-97%, which can improve the energy density of the negative electrode sheet.
  • the mass content of the first active material in the first active material layer can be 95%-97.2%, which can improve the energy density of the positive electrode sheet.
  • the mass content of the second active material in the second active material layer is 96.2%-98.5%, which can improve the energy density and conductivity of the electrode sheet.
  • the mass content of the second active material in the second active material layer can be, but is not limited to, 96.2%, 96.5%, 96.8%, 97%, 9.75%, or 98.5%.
  • the mass content of the second active material in the second active material layer can be 96.2%-98.5%, which can improve the energy density of the negative electrode sheet.
  • the mass content of the second active material in the second active material layer can be 97%-98.5%, which can improve the energy density of the positive electrode sheet.
  • particle size D50 refers to the particle size corresponding to a cumulative volume distribution percentage of 50%.
  • the primary particle size D50 of the first active material is smaller than that of the second active material.
  • a smaller primary particle size D50 results in a larger specific surface area, more ion insertion/extraction sites, and a shorter lithium-ion diffusion distance, which is beneficial for improving conductivity and specific capacity.
  • the second active material layer is close to the tab region, the temperature rises during charging and discharging.
  • Using an active material with a larger primary particle size allows for improved kinetic performance due to increased temperature, thereby enhancing the conductivity of the second active material layer. This improves the high-temperature resistance and lifespan of the electrode, reduces the manufacturing cost of the electrode, and prevents lithium plating during use.
  • the mass content of the carbon coating layer of the first active material is greater than that of the carbon coating layer of the second active material.
  • a higher mass content of the carbon coating layer results in a thicker coating, which improves the conductivity of the active material.
  • the second active material layer is close to the tab region, its temperature rises during charging and discharging. Therefore, an active material with a lower carbon coating layer mass content can be used.
  • the high conductivity of the second active material layer can be maintained, thereby increasing the volumetric energy density and gravimetric energy density of the electrode sheets. This, in turn, improves the thermal stability and safety performance of the battery, and reduces the risk of thermal runaway.
  • the primary particle size D50 of the first active material is 0.3 ⁇ m-9 ⁇ m.
  • the primary particle size D50 of the first active material can be, but is not limited to, 0.3 ⁇ m, 1 ⁇ m, 2 ⁇ m, 4 ⁇ m, 6 ⁇ m, 8 ⁇ m, or 9 ⁇ m.
  • the primary particle size D50 of the first active material when the first active material is a negative electrode active material, can be 6 ⁇ m-9 ⁇ m.
  • the primary particle size D50 of the first active material when the first active material is a positive electrode active material, the primary particle size D50 of the first active material can be 0.3 ⁇ m-1.3 ⁇ m.
  • the primary particle size D50 of the second active material is 0.7 ⁇ m-15 ⁇ m.
  • the primary particle size D50 of the second active material can be, but is not limited to, 0.7 ⁇ m, 1 ⁇ m, 2 ⁇ m, 8 ⁇ m, 10 ⁇ m, 13 ⁇ m, or 15 ⁇ m.
  • the primary particle size D50 of the second active material when the second active material is a negative electrode active material, can be 9 ⁇ m-15 ⁇ m.
  • the primary particle size of the second active material when the second active material is a positive electrode active material, the primary particle size of the second active material can be 0.7 ⁇ m-2 ⁇ m.
  • the mass content of the carbon coating layer of the first active material is 0.5%-2%.
  • a higher mass content of the carbon coating layer indicates a greater amount of carbon coated on the surface of the active material, resulting in a thicker carbon layer.
  • An appropriate mass content of the carbon coating layer is beneficial for improving the conductivity of the active material, enhancing battery safety performance, and reducing the risk of thermal runaway.
  • the mass content of the carbon coating layer of the first active material can be, but is not limited to, 0.5%, 1%, 1.2%, 1.6%, 1.8%, or 2%.
  • the mass content of the carbon coating layer of the second active material is less than or equal to 0.5%.
  • the mass content of the carbon coating layer of the second active material may be, but is not limited to, less than or equal to 0.5%, less than or equal to 0.4%, less than or equal to 0.3%, less than or equal to 0.2%, or less than or equal to 0.1%.
  • the mass content of the carbon coating layer of the second active material may be less than or equal to 0.5%.
  • the first active material layer further includes a first conductive agent and a first binder.
  • the first conductive agent can improve the conductivity of the electrode sheet
  • the first binder can improve the bonding ability between the components of the first active material layer and between the first active material layer and the current collector, which is beneficial to improving the mechanical properties of the electrode sheet.
  • the first conductive agent can be either a positive or negative conductive agent.
  • the first conductive agent is a positive conductive agent
  • the first conductive agent is a negative conductive agent, which can improve the conductivity of the electrode sheet.
  • the positive conductive agent may include, but is not limited to, at least one of carbon nanotubes, acetylene black, graphene, conductive graphite, and carbon black
  • the negative conductive agent may include, but is not limited to, at least one of carbon nanotubes, acetylene black, graphene, conductive graphite, and carbon black.
  • the first conductive agent when the first conductive agent is a positive conductive agent, can be carbon nanotubes. In another embodiment of this application, when the first conductive agent is a negative conductive agent, the first conductive agent can be carbon black.
  • the mass content of the first conductive agent in the first active material layer is 0.5%-2%, which can improve the conductivity of the electrode sheet.
  • the mass content of the first conductive agent in the first active material layer can be, but is not limited to, 0.5%, 0.8%, 1%, 1.5%, 1.8%, or 2%.
  • the mass content of the first conductive agent in the first active material layer can be 1%-2%.
  • the mass content of the first conductive agent in the first active material layer can be 0.5%-2%.
  • the first binder can be either a positive electrode binder or a negative electrode binder.
  • the first binder is a positive electrode binder; when the electrode sheet is a negative electrode sheet, the first binder is a negative electrode binder, which can improve the mechanical properties of the electrode sheet.
  • the positive electrode binder may include, but is not limited to, at least one of polyvinylidene fluoride, polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, polystyrene, polybutadiene, acrylic resin, epoxy resin, polyethylene oxide, sodium carboxymethyl cellulose, and styrene-butadiene rubber;
  • the negative electrode binder may include, but is not limited to, at least one of polyvinylidene fluoride, polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, polystyrene, polybutadiene, acrylic resin, epoxy resin, polyethylene oxide, sodium carboxymethyl cellulose, and styrene-butadiene rubber.
  • the first binder when the first binder is a positive electrode binder, can be polyvinylidene fluoride. In another embodiment of this application, when the first binder is a negative electrode binder, the first binder can be styrene-butadiene rubber.
  • the mass content of the first binder in the first active material layer is 1%-3%.
  • a suitable first binder can improve the mechanical properties of the electrode sheet.
  • the mass content of the first binder in the first active material layer can be, but is not limited to, 1%, 1.2%, 1.8%, 2%, 2.4%, 2.6%, 2.8%, or 3%.
  • the mass content of the first binder in the first active material layer can be 1.8%-3%.
  • the mass content of the first binder in the first active material layer can be 1%-2%.
  • the second active material layer further includes a second conductive agent and a second binder.
  • the second conductive agent can improve the conductivity of the electrode sheet
  • the second binder can improve the bonding ability between the components of the second active material layer and between the second active material layer and the current collector, which is beneficial to improving the mechanical properties of the electrode sheet.
  • the second conductive agent can be either a positive or negative conductive agent.
  • the second conductive agent is a positive conductive agent
  • the second conductive agent is a negative conductive agent, which can improve the conductivity of the electrode.
  • the positive conductive agent may include, but is not limited to, at least one of carbon nanotubes, acetylene black, graphene, conductive graphite, and carbon black
  • the negative conductive agent may include, but is not limited to, at least one of carbon nanotubes, acetylene black, graphene, conductive graphite, and carbon black.
  • the second conductive agent when the second conductive agent is a positive conductive agent, can be conductive graphite. In another embodiment of this application, when the second conductive agent is a negative conductive agent, the second conductive agent can be carbon nanotubes.
  • the mass content of the second conductive agent in the second active material layer is less than or equal to 1%.
  • An appropriate mass of the second conductive agent can mitigate lithium plating on the electrode sheet.
  • the mass content of the second conductive agent in the second active material layer may be, but is not limited to, less than or equal to 1%, less than or equal to 0.8%, less than or equal to 0.7%, less than or equal to 0.5%, less than or equal to 0.3%, or less than or equal to 0.1%, etc.
  • the second binder can be either a positive or negative electrode binder.
  • the second binder is a positive electrode binder; when the electrode sheet is a negative electrode sheet, the second binder is a negative electrode binder, which can improve the mechanical properties of the electrode sheet.
  • the positive electrode binder may include, but is not limited to, at least one of polyvinylidene fluoride, polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, polystyrene, polybutadiene, acrylic resin, epoxy resin, polyethylene oxide, sodium carboxymethyl cellulose, and styrene-butadiene rubber;
  • the negative electrode binder may include, but is not limited to, at least one of polyvinylidene fluoride, polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, polystyrene, polybutadiene, acrylic resin, epoxy resin, polyethylene oxide, sodium carboxymethyl cellulose, and styrene-butadiene rubber.
  • the second binder when the second binder is a positive electrode binder, the second binder can be polyvinylidene fluoride. In another embodiment of this application, when the second binder is a negative electrode binder, the second binder can be polytetrafluoroethylene.
  • the mass content of the second binder in the second active material layer is 0.5%-2%.
  • the mass content of the second binder in the second active material layer can be, but is not limited to, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, or 2%.
  • the mass content of the second binder in the second active material layer can be 1.5%-2%.
  • the mass content of the second binder in the second active material layer can be 0.5%-1.2%.
  • the mass content of the first conductive agent in the first active material layer is greater than the mass content of the second conductive agent in the second active material layer. Since the second active material layer is close to the tab region, its temperature rises during charging and discharging. This temperature increase improves the kinetic properties of the second active material, maintaining its high conductivity and thus reducing the amount of conductive agent used and lowering the manufacturing cost of the electrode sheet.
  • the mass content of the first binder in the first active material is greater than the mass content of the second binder in the second active material layer. Because the content of the second conductive agent decreases in the second active material layer, its solid content is reduced. Therefore, a binder with a lower mass content can be used, which can achieve dispersion of the second active material and the second conductive agent without affecting the mechanical properties of the electrode sheet, thus reducing the manufacturing cost of the electrode sheet and facilitating its industrial application.
  • the first active material layer when the electrode sheet is a negative electrode sheet, the first active material layer further includes a first thickener, which can promote the uniform distribution of the first active material layer.
  • the first thickener may include, but is not limited to, sodium carboxymethyl cellulose or lithium carboxymethyl cellulose.
  • the first thickener may be sodium carboxymethyl cellulose, and in this case, the negative electrode binder may be styrene-butadiene rubber.
  • the mass content of the first thickener in the first active material layer is 1.5%-3%.
  • the mass content of the first thickener in the first active material layer can be, but is not limited to, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.7%, 2.8%, or 3%.
  • the mass content of the first thickener in the first active material layer can be 1.5%-2.5%.
  • the mass content of the first thickener in the first active material layer can be 2%-3%.
  • the second active material layer when the electrode sheet is a negative electrode sheet, the second active material layer further includes a second thickener, which can promote the uniform distribution of the second active material layer.
  • the second thickener may include, but is not limited to, sodium carboxymethyl cellulose or lithium carboxymethyl cellulose.
  • the second thickener may be sodium carboxymethyl cellulose
  • the negative electrode binder may be styrene-butadiene rubber.
  • the mass content of the second thickener in the second active material layer is 1%-1.5%.
  • the mass content of the second thickener in the second active material layer can be, but is not limited to, 1%, 1.2%, 1.3%, 1.4%, or 1.5%.
  • the mass content of the second thickener in the second active material layer can be 1%-1.2%.
  • the mass content of the second thickener in the second active material layer can be 1.2%-1.5%.
  • the thickness of the first active material layer is 92 ⁇ m-300 ⁇ m.
  • the thickness of the first active material layer can be, but is not limited to, 92 ⁇ m, 100 ⁇ m, 150 ⁇ m, 200 ⁇ m, 250 ⁇ m, or 300 ⁇ m.
  • the thickness of the first active material layer can be 130 ⁇ m-300 ⁇ m.
  • the thickness of the first active material can be 100 ⁇ m-180 ⁇ m.
  • the size of the first active material layer is 80mm-1000mm along the direction from the second active material layer to the first active material layer.
  • a larger size of the first active material layer is beneficial for improving the energy density of the electrode sheet.
  • the size of the first active material layer along the direction from the second active material layer to the first active material layer can be, but is not limited to, 80mm, 100mm, 200mm, 400mm, 600mm, 800mm, or 1000mm.
  • the size of the first active material layer along the direction from the second active material layer to the first active material layer can be 80mm-600mm.
  • the size of the first active material layer along the direction from the second active material layer to the first active material layer can be 500mm-1000mm.
  • the maximum thickness of the second active material layer is 92 ⁇ m-300 ⁇ m.
  • the maximum thickness of the second active material layer can be, but is not limited to, 92 ⁇ m, 100 ⁇ m, 120 ⁇ m, 150 ⁇ m, 180 ⁇ m, 220 ⁇ m, 250 ⁇ m, or 300 ⁇ m.
  • the maximum thickness of the second active material layer is 120 ⁇ m-270 ⁇ m.
  • the maximum thickness of the second active material layer is 92 ⁇ m-165 ⁇ m.
  • the thickness of the second active material layer gradually decreases from 92 ⁇ m-300 ⁇ m to 0 ⁇ m.
  • the size of the second active material layer is 10mm-30mm along the direction from the first active material layer to the second active material layer.
  • a smaller size of the second active material layer helps reduce lithium plating on the electrode sheet.
  • the size of the second active material layer along the direction from the first active material layer to the second active material layer can be, but is not limited to, 10mm, 15mm, 20mm, 25mm, or 30mm.
  • the size of the second active material layer is 10mm-20mm along the direction from the first active material layer to the second active material layer.
  • the size of the second active material layer is 15mm-30mm along the direction from the first active material layer to the second active material layer.
  • the areal density of the electrode sheet is 150 g/ m2 - 600 g/ m2 .
  • a suitable areal density can increase the energy density of the electrode sheet, thereby increasing the battery capacity and reducing the battery's internal resistance.
  • the negative electrode sheet has a thinned region, while the corresponding positive electrode sheet is a normally coated region. This results in a decrease in the ratio of the negative electrode capacity to the positive electrode capacity in the thinned region, leading to severe lithium plating and shortening the battery's lifespan.
  • Related technologies increase the overall areal density of the negative electrode sheet to improve its capacity, but this increases the manufacturing cost of the negative electrode sheet and reduces its volumetric and gravimetric energy densities.
  • the electrode sheet provided in this application has a similar areal density to electrode sheets in related technologies. Without changing the areal density, by controlling the relationship between the first active material in the first active material layer and the second active material in the second active material layer, the capacity of the second active material layer (thinned region) is increased, thereby improving the capacity of the electrode sheet. This mitigates lithium plating while maintaining high volumetric and gravimetric energy densities, and reduces the manufacturing cost of the electrode sheet.
  • the areal density of the electrode sheet can be, but is not limited to, 150 g/ m2 , 200 g/ m2 , 250 g/ m2 , 300 g/ m2 , 350 g/ m2 , 400 g/ m2 , 450 g/ m2 , 500 g/ m2 , 550 g/ m2 , or 600 g/ m2 , etc.
  • the areal density of the positive electrode sheet can be 300 g/ m2 - 600 g/ m2
  • the areal density of the first active material layer can be 300 g/ m2 - 600 g/ m2
  • the areal density of the second active material layer is 276 g/ m2 - 599 g/ m2 , with the areal density of the second active material layer gradually decreasing along the direction from the first active material layer to the second active material layer.
  • the areal density of the negative electrode sheet can be 150 g/ m2 - 300 g/ m2
  • the areal density of the first active material layer can be 150 g/ m2 - 300 g/ m2
  • the areal density of the second active material layer is 142 g/ m2 - 299 g/ m2 , with the areal density of the second active material layer gradually decreasing along the direction from the first active material layer to the second active material layer.
  • One embodiment of this application provides a method for preparing an electrode sheet, comprising:
  • a first slurry and a second slurry are coated onto the surface of the current collector.
  • the first slurry includes a first active material
  • the second slurry includes a second active material.
  • an electrode sheet is obtained.
  • the preparation method provided in this application is novel, the preparation process is simple, and the preparation cost is low. It can produce electrode sheets with high volumetric energy density and gravimetric energy density that are not prone to lithium plating reaction.
  • the electrode sheet provided in any of the above embodiments can be prepared by this preparation method.
  • the first slurry further includes a first conductive agent and a first binder.
  • the mass ratio of the first active material, the first conductive agent, and the first binder is (93-97.2):(0.5-2):(1-3).
  • a suitable first slurry ratio can alleviate lithium plating on the electrode sheet and improve the energy density of the electrode sheet.
  • the mass ratio of the first active material, the first conductive agent, and the first binder can be, but is not limited to, 93:0.5:1, 93.5:0.8:1.5, 94:1:1.8, 94.5:1.2:1.8, 95:1.5:2, 96:1.8:2.2, 96.5:1.8:2.5, 97:2:2.8, or 97.2:2:3, etc.
  • the mass ratio of the first active material, the first conductive agent, and the first binder can be (93-96):(0.5-1.5):(1-2.2). In another embodiment of this application, the mass ratio of the first active material, the first conductive agent and the first binder can be (95-97.2):(1-2):(2-3).
  • the first slurry when the electrode sheet is a negative electrode sheet, the first slurry further includes a thickener.
  • the mass ratio of the first active material, the first conductive agent, the first binder, and the first thickener is (93-97.2):(0.5-2):(1-3):(1.5-3), which can increase the viscosity of the first slurry and promote its coating ability.
  • the mass ratio of the first active material, the first conductive agent, the first binder, and the first thickener can be, but is not limited to, 93:0.5:1:1.5, 93.5:0.8:1.5:1.8, 94:1:1.8:1.9, 94.5:1.2:1.8:2, 95:1.5:2:2.2, 96:1.8:2.2:2.5, 96.5:1.8:2.5:2.8, 97:2:2.8:2.9, or 97.2:2:3:3, etc.
  • the mass ratio of the first active material, the first conductive agent, the first binder, and the first thickener can be (93-96):(0.5-1):(1-1.8):(1.5-2.5).
  • the mass ratio of the first active material, the first conductive agent, the first binder, and the first thickener can be (95-97.2):(1-2):(1.5-3):(2-3).
  • the first slurry further includes a first solvent, the mass content of which is 20%-50%.
  • the first solvent can improve the coating ability of the first slurry and promote the uniform distribution of the first active material in the first active material layer.
  • the first solvent may be, but is not limited to, N-methylpyrrolidone; the mass content of the first solvent may be, but is not limited to, 20%, 25%, 30%, 35%, 40%, 45%, or 50%.
  • the first solvent may be N-methylpyrrolidone, and the mass content of the first solvent in the first slurry may be 20%-35%.
  • the second slurry further includes a second conductive agent and a second binder.
  • the mass ratio of the second active material, the second conductive agent, and the second binder is (96.2-98.5):(0-1):(0.5-2), which can reduce the probability of lithium plating on the electrode sheet and increase the energy density of the electrode sheet.
  • the mass ratio of the second active material, the second conductive agent, and the second binder can be, but is not limited to, 96.2:0:0.5, 96.5:0.1:0.7, 96.8:0.3:0.8, 97:0.5:1, 97.5:0.7:1, 97.8:0.8:1.5, 98:0.8:1.8, or 98.5:1:2, etc.
  • the mass ratio of the second active material, the second conductive agent, and the second binder can be (96.2-97.5):(0-0.6):(0.5-1.5). In another embodiment of this application, the mass ratio of the second active material, the second conductive agent, and the second binder can be (97-98.5):(0.4-1):(1-2).
  • the second slurry when the electrode sheet is a negative electrode sheet, the second slurry further includes a thickener.
  • the mass ratio of the second active material, the second conductive agent, the second binder, and the second thickener is (96.2-98.5):(0-1):(0.5-2):(1-1.5), which can increase the viscosity of the second slurry and promote its coating ability.
  • the mass ratio of the second active material, the second conductive agent, the second binder, and the second thickener can be, but is not limited to, 96.2:0:0.5:1, 96.5:0.1:0.7:1.1, 96.8:0.3:0.8:1.2, 97:0.5:1:1.3, 97.5:0.7:1:1.3, 97.8:0.8:1.5:1.4, 98:0.8:1.8:1.4, or 98.5:1:2:1.5, etc.
  • the mass ratio of the second active material, the second conductive agent, the second binder, and the second thickener can be (96.2-97.5):(0-0.6):(0.5-1.5):(1-1.3).
  • the mass ratio of the second active material, the second conductive agent, the second binder, and the second thickener can be (97-98.5):(0.5-1):(1-2):(1.2-1.5).
  • the second slurry further includes a second solvent, the mass content of which is 20%-50%.
  • the second solvent can improve the coating ability of the second slurry and promote the uniform distribution of the second active material in the second active material layer.
  • the second solvent may be, but is not limited to, N-methylpyrrolidone; the mass content of the second solvent in the second slurry may be, but is not limited to, 20%, 25%, 30%, 35%, 40%, 45%, or 50%.
  • the second solvent may be N-methylpyrrolidone, and the mass content of the second solvent in the second slurry may be 20%-35%.
  • This application also provides a battery, including a positive electrode and a negative electrode, and a separator disposed between the positive and negative electrode.
  • the negative electrode includes the electrode sheet described in any of the above embodiments or the electrode sheet prepared by the preparation method described in any of the above embodiments.
  • the negative electrode provided by this application increases the capacity of the thinned region of the negative electrode, increases the capacity ratio of the negative electrode to the positive electrode in the battery, reduces the risk of lithium plating on the electrode, and is beneficial to improving the electrochemical performance and service life of the electrode, thus facilitating the industrial application of the battery.
  • the positive electrode sheet includes the electrode sheet described in any of the above embodiments or the electrode sheet prepared by the preparation method described in any of the above embodiments. That is, both the positive and negative electrode sheets are electrode sheets provided in this application.
  • the negative electrode sheet includes a negative current collector and a negative active material layer disposed on the surface of the negative current collector.
  • the negative active material layer includes a first negative active material layer and a second negative active material layer. Along the direction from the first negative active material layer to the second negative active material layer, the thickness of the second negative active material layer gradually decreases, and the mass content of the first negative active material in the first negative active material layer is less than that of the second negative active material in the second negative active material layer.
  • the positive electrode sheet includes a positive current collector and a positive active material layer disposed on the surface of the positive current collector.
  • the positive active material layer includes a first positive active material layer and a second positive active material layer. Along the direction from the first positive active material layer to the second positive active material layer, the thickness of the second positive active material layer gradually decreases, and the mass content of the first positive active material in the first positive active material layer is less than that of the second positive active material in the second positive active material layer.
  • the positive and negative electrode sheets are arranged opposite each other, with the first positive active material layer of the positive electrode sheet and the second negative active material layer of the negative electrode sheet being arranged opposite each other, and the second positive active material layer of the positive electrode sheet and the first negative active material layer of the negative electrode sheet being arranged opposite each other. This helps to further alleviate the lithium plating phenomenon in the battery and improve the battery capacity and cycle stability.
  • the separator can perform ion exchange, forming a complete ion conduction pathway.
  • the separator can be, but is not limited to, woven membrane, nonwoven fabric, microporous membrane, composite membrane, rolled membrane, or separator paper, etc.
  • the battery also includes an electrolyte. At least a portion of the positive electrode and at least a portion of the negative electrode are immersed in the electrolyte.
  • the electrolyte in this application is not particularly limited and can be, but is not limited to, any substance in the art that can be used as a battery electrolyte.
  • the electrical device also provides an electrical device, which includes the battery described in any of the above embodiments.
  • the electrical device provided by this application has high energy density, high safety performance, and strong market competitiveness.
  • the electrical device includes mobile phones, tablets, watches, VR glasses, vehicles, etc.
  • the battery can be used in vehicles, which can improve vehicle electrical safety and charging speed, promote the widespread application of new energy vehicles, and contribute to the construction of a green and environmentally friendly environment.
  • the battery can also be used in mobile phones, which can reduce battery manufacturing costs and improve battery life and safety.
  • the electrical device in this application can refer to vehicles, electronic devices, energy storage systems, etc., and the battery can be installed in the electrical device in the form of a single cell, battery module, battery pack, capacitor, etc.
  • the first positive electrode active material lithium iron phosphate, primary particle size D50 is 0.4 ⁇ m
  • the first positive electrode conductive agent carbon black
  • the first positive electrode binder polyvinylidene fluoride
  • the mass content of the first positive electrode active material in the solid component of the first positive electrode slurry is 96.5%
  • the mass content of the first positive electrode conductive agent is 1%
  • the mass content of the first positive electrode binder is 2.5%.
  • a second positive electrode slurry is prepared by mixing a second positive electrode active material (lithium iron phosphate, with a primary particle size D50 of 0.8 ⁇ m), a second positive electrode conductive agent (carbon black), a second positive electrode binder (polyvinylidene fluoride), and a second solvent (N-methylpyrrolidone).
  • the solid components of the second positive electrode slurry contain 97.7% by mass of the second positive electrode active material, 0.5% by mass of the second positive electrode conductive agent, and 1.8% by mass of the second positive electrode binder.
  • the first positive electrode slurry and the second positive electrode slurry are coated onto the positive electrode current collector, and after drying, a positive electrode sheet is obtained.
  • the first positive electrode slurry forms a first positive electrode active material layer (non-thinned region), the thickness of which is 250 ⁇ m and the areal density of which is 450 g/ m2 .
  • the second positive electrode slurry forms a second positive electrode active material layer (thinned region), and the thickness of which gradually decreases from 250 ⁇ m to 230 ⁇ m along the direction from the first positive electrode active material layer to the second positive electrode active material layer.
  • the areal density of which is 420 g/ m2 .
  • a first negative electrode slurry is prepared by mixing a first negative electrode active material (artificial graphite with a primary particle size D50 of 8 ⁇ m), a first negative electrode conductive agent (carbon black), a first negative electrode binder (styrene-butadiene rubber), and a first thickener (sodium carboxymethyl cellulose) with a first solvent (N-methylpyrrolidone).
  • the first negative electrode slurry contains 96.1% by mass of the first negative electrode active material, 1% by mass of the first negative electrode conductive agent, 1.3% by mass of the first negative electrode binder, and 1.6% by mass of the first thickener in its solid components.
  • a second negative electrode slurry is prepared by mixing a second negative electrode active material (artificial graphite with a primary particle size D50 of 13 ⁇ m), a second negative electrode binder (styrene-butadiene rubber), a second thickener (sodium carboxymethyl cellulose), and a second solvent (N-methylpyrrolidone).
  • the solid components of the second negative electrode slurry contain 97.6% by mass of the second negative electrode active material, 1.1% by mass of the second negative electrode binder, and 1.3% by mass of the second thickener.
  • the first negative electrode slurry and the second negative electrode slurry are coated onto the negative electrode current collector, and after drying, a negative electrode sheet is obtained.
  • the first negative electrode slurry forms a first negative electrode active material layer (non-thinned region), the thickness of which is 135 ⁇ m and the areal density of which is 204 g/ m2 .
  • the second negative electrode slurry forms a second negative electrode active material layer (thinned region), and the thickness of which gradually decreases from 135 ⁇ m to 125 ⁇ m along the direction from the first negative electrode active material layer to the second negative electrode active material layer.
  • the areal density of which is 190 g/ m2 .
  • the first negative electrode slurry includes a first negative electrode active material (artificial graphite), a first negative electrode conductive agent (carbon black), a first negative electrode binder (styrene-butadiene rubber), and a first thickener (sodium carboxymethyl cellulose).
  • the mass content of the first negative electrode active material in the solid component of the first negative electrode slurry is 93%, the mass content of the first negative electrode conductive agent is 2%, the mass content of the first negative electrode binder is 2%, and the mass content of the first thickener is 3%.
  • the second negative electrode slurry includes a second negative electrode active material (artificial graphite), a second negative electrode conductive agent (carbon black), a second negative electrode binder (styrene-butadiene rubber), and a second thickener (sodium carboxymethyl cellulose).
  • the solid components of the second negative electrode slurry contain 98.5% by mass of the second negative electrode active material, 0.1% by mass of the second negative electrode conductive agent, 0.4% by mass of the second negative electrode binder, and 1% by mass of the second thickener.
  • the first positive electrode slurry includes a first positive electrode active material (lithium iron phosphate), a first positive electrode conductive agent (carbon black), and a first positive electrode binder (polyvinylidene fluoride).
  • the mass content of the first positive electrode active material in the solid components of the first positive electrode slurry is 92%, the mass content of the first positive electrode conductive agent is 4%, and the mass content of the first positive electrode binder is 4%.
  • the second positive electrode slurry includes a second positive electrode active material (lithium iron phosphate), a second positive electrode conductive agent (carbon black), and a second positive electrode binder (polyvinylidene fluoride).
  • the solid components of the second positive electrode slurry contain 99% by mass of the second positive electrode active material, 0.5% by mass of the second positive electrode conductive agent, and 0.5% by mass of the second positive electrode binder.
  • Example 1 The difference from Example 1 is that in the negative electrode sheet, the first negative electrode active material is natural graphite.
  • Example 1 The difference from Example 1 is that the first negative electrode slurry contains 96% by mass of the first negative electrode active material, 0.6% by mass of the first negative electrode conductive agent, 1.8% by mass of the first negative electrode binder, and 1.6% by mass of the first thickener in its solid components; and the second negative electrode slurry contains 96.8% by mass of the second negative electrode active material, 0.8% by mass of the second negative electrode conductive agent, 1.1% by mass of the second negative electrode binder, and 1.3% by mass of the second thickener in its solid components.
  • Example 1 The difference from Example 1 is that the first negative electrode slurry contains 96.2% by mass of the first negative electrode active material, 1% by mass of the first negative electrode conductive agent, 1.2% by mass of the first negative electrode binder, and 1.6% by mass of the first thickener in its solid components; and the second negative electrode slurry contains 96.3% by mass of the second negative electrode active material, 1% by mass of the second negative electrode conductive agent, 1.4% by mass of the second negative electrode binder, and 1.3% by mass of the second thickener in its solid components.
  • Example 1 The difference from Example 1 is that the first negative electrode slurry contains 94% by mass of the first negative electrode active material, 3% by mass of the first negative electrode conductive agent, 1.3% by mass of the first negative electrode binder, and 1.6% by mass of the first thickener in its solid components; and the second negative electrode slurry contains 96.1% by mass of the second negative electrode active material, 1.5% by mass of the second negative electrode conductive agent, 1.1% by mass of the second negative electrode binder, and 1.3% by mass of the second thickener in its solid components.
  • Example 1 The difference from Example 1 is that the first negative electrode slurry contains 93.4% by mass of the first negative electrode active material, 1% by mass of the first negative electrode conductive agent, 4% by mass of the first negative electrode binder, and 1.6% by mass of the first thickener in its solid components; and the second negative electrode slurry contains 94.7% by mass of the second negative electrode active material, 1% by mass of the second negative electrode conductive agent, 3% by mass of the second negative electrode binder, and 1.3% by mass of the second thickener in its solid components.
  • Example 1 The difference from Example 1 is that the positive electrode sheet is prepared by coating the positive electrode slurry onto the positive electrode current collector, the thickness of the non-thinned region of the positive electrode sheet is 250 ⁇ m, and the thickness of the thinned region of the positive electrode sheet gradually decreases from 250 ⁇ m to 230 ⁇ m.
  • Example 1 The difference from Example 1 is that the negative electrode sheet is prepared by coating the negative electrode slurry onto the negative electrode current collector, the thickness of the non-thinned area of the negative electrode sheet is 135 ⁇ m, and the thickness of the thinned area of the negative electrode sheet gradually decreases from 135 ⁇ m to 125 ⁇ m.
  • Example 9 The difference from Example 9 is that the negative electrode sheet is prepared by coating the negative electrode slurry onto the negative electrode current collector, the thickness of the non-thinned area of the negative electrode sheet is 135 ⁇ m, and the thickness of the thinned area of the negative electrode sheet gradually decreases from 135 ⁇ m to 125 ⁇ m.
  • Example 9 The difference from Example 9 is that the negative electrode sheet is prepared by coating the negative electrode slurry onto the negative electrode current collector, the non-thinned region of the negative electrode sheet has a thickness of 135 ⁇ m, and the thickness of the thinned region of the negative electrode sheet gradually decreases from 135 ⁇ m to 125 ⁇ m; the positive electrode sheet is prepared by coating the first positive electrode slurry onto the positive electrode current collector, the non-thinned region of the positive electrode sheet has a thickness of 250 ⁇ m, and the thickness of the thinned region of the positive electrode sheet gradually decreases from 250 ⁇ m to 230 ⁇ m.
  • Example 9 The difference from Example 9 is that in the negative electrode sheet, the first negative electrode slurry forms the second negative electrode active material layer, and the second negative electrode slurry forms the first negative electrode active material layer.
  • the negative electrode sheet, positive electrode sheet and separator prepared in Examples 1-10 and Comparative Examples 1-3 are stacked together and assembled with an aluminum shell. After assembly, the battery is obtained through processes such as cover plate welding, shell welding, baking, liquid injection, aging and formation.
  • the batteries prepared in Examples 1-10 and Comparative Examples 1-3 were subjected to mass energy density testing.
  • the batteries prepared in Examples 1-10 and Comparative Examples 1-3 were subjected to volumetric energy density testing.
  • the testing procedure was as follows: at room temperature (25°C), the batteries were charged at a constant current of 1C to 3.8V, followed by constant voltage charging to a cutoff current of 0.05C. After fully charging, the batteries were discharged at a 1/3C discharge rate. The energy at this 1/3C discharge rate was calculated and recorded as battery energy, denoted as W. Simultaneously, the battery volume was measured and recorded, denoted as V.
  • the volumetric energy density (Wh/L) W/V.
  • the test results are shown in Table 1.
  • the batteries prepared in Examples 1-10 and Comparative Examples 1-3 were subjected to cycle tests. After 100 cycles, the samples that had undergone 100 cycles were disassembled, and the interface of the negative electrode was photographed and observed. The test results are shown in Table 1.
  • the batteries prepared in Examples 1-10 and Comparative Examples 1-3 were subjected to fast-charge cycle tests.
  • the test procedure was as follows: after being left to rest at room temperature (25°C) for 30 minutes, the batteries were charged at a constant current of 2.65C to 30% SOC, then at a constant current of 2C to 40% SOC, then at a constant current of 1.7C to 65% SOC, then at a constant current of 1.4C to 70% SOC, then at a constant current of 1.1C to 75% SOC, then at a constant current of 0.8C to 90% SOC, then at a constant current of 0.65C to 95% SOC, and finally at a constant current of 0.3C to 100% SOC.
  • the batteries were discharged at a discharge rate of 1C.
  • the above steps were repeated until the state of health (SOH) of the battery reached 80%.
  • SOH state of health
  • the electrode sheet provided in this application by controlling the relationship between the mass content of the first active material in the first active material layer and the mass content of the second active material layer in the second active material layer, reduces the probability of lithium plating during use of the electrode sheet without reducing its volumetric energy density and gravimetric energy density, which is beneficial to improving the electrochemical performance of the battery.
  • suitable contents of active materials, binders, and conductive agents can further improve the energy density of the electrode sheet and reduce the probability of lithium plating.
  • the electrode sheet provided in this application improves the lithium plating phenomenon by improving the mass relationship between the first and second active materials, resulting in a good energy density that is beneficial to improving the overall performance of the battery.

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Abstract

本申请提供了一种电极极片、电池及用电设备，所述电极极片包括集流体和设置在所述集流体至少一侧表面的活性材料层，所述活性材料层包括第一活性材料层和与所述第一活性材料层同层设置且相连接的第二活性材料层，沿所述第一活性材料层至所述第二活性材料层的方向上，所述第二活性材料层的厚度逐渐减小，所述第一活性材料层包括第一活性材料，所述第二活性材料层包括第二活性材料，所述第一活性材料层中的第一活性材料的质量含量小于所述第二活性材料层中的第二活性材料层的质量含量。本申请提供的电极极片不易发生析锂反应，体积能量密度和质量能量密度高，制备成本低，有利于提高电池的容量和使用寿命。

Description

电极极片、电池及用电设备
本申请要求于2024年06月27日提交中国专利局、申请号为202410851853.X、申请名称为“电极极片、电池及用电设备”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及电池领域，具体涉及电极极片、电池及用电设备。
背景技术
目前，为了提高电极极片的产能，采用多幅涂布进行电极极片的制备，电极极片中相对区域容量不匹配，导致负极容量与正极容量的比值降低，易发生析锂现象，不利于提高电池的循环稳定性。相关技术中，通过提高电极极片的面密度以提高负极容量与正极容量的比值，降低析锂现象的发生概率，但该方法会导致电极极片发生体积能量密度和重量能量密度的下降，制备成本的增加，不利于提高电极极片的广泛应用。因此，需要一种不易发生析锂现象、体积能量密度和重量能量密度高、制备成本低的电极极片。
发明内容
鉴于此，本申请提供了一种电极极片、电池及用电设备，该电极极片不易发生析锂现象，体积能量密度和重量能量密度高，制备成本低，有利于提高电池的电化学性能和工业化应用。
第一方面，本申请提供了一种电极极片，所述电极极片包括集流体和设置在所述集流体至少一侧表面的活性材料层，所述活性材料层包括第一活性材料层和与所述第一活性材料层同层设置且相连接的第二活性材料层，沿所述第一活性材料层至所述第二活性材料层的方向上，所述第二活性材料层的厚度逐渐减小，所述第一活性材料层包括第一活性材料，所述第二活性材料层包括第二活性材料，所述第一活性材料层中的第一活性材料的质量含量小于所述第二活性材料层中的第二活性材料层的质量含量。
可选的，所述第二活性材料层设置在所述第一活性材料层的一侧，或所述第二活性材料层设置所述第一活性材料层的相对两侧。
可选的，所述第一活性材料层中，所述第一活性材料的质量含量为93％-97.2％。
可选的，所述第二活性材料层中，所述第二活性材料的质量含量为96.2％-98.5％。
可选的，所述第一活性材料的一次颗粒粒径D50小于所述第二活性材料的一次颗粒粒径D50。
可选的，所述第一活性材料的碳包覆层的质量含量大于所述第二活性材料的碳包覆层的质量含量。
可选的，所述第一活性材料的一次颗粒粒径D50为0.3μm-9μm。
可选的，所述第二活性材料的一次颗粒粒径D50为0.7μm-15μm。
可选的，所述第一活性材料的碳包覆层的质量含量为0.5％-2％。
可选的，所述第二活性材料的碳包覆层的质量含量小于或等于0.5％。
可选的，所述第一活性材料层还包括第一导电剂和第一粘结剂，所述第二活性材料层还包括第二导电剂和第二粘结剂。
可选的，所述第一活性材料层中的所述第一导电剂的质量含量大于所述第二活性材料层中的所述第二导电剂的质量含量。
可选的，所述第一活性材料层中的第一粘结剂的质量含量大于所述第二活性材料层中的所述第二粘结剂的质量含量。
可选的，所述第一活性材料层中，所述第一导电剂的质量含量为0.5％-2％，所述第一粘结剂的质量含量为1％-3％。
可选的，所述第二活性材料层中，所述第二导电剂的质量含量小于或等于1％，所述第二粘结剂的质量含量为0.5％-2％。
可选的，所述第一活性材料层的厚度为92μm-300μm，所述第二活性材料层的最大厚度为92μm-300μm。
可选的，沿所述第二活性材料层至所述第一活性材料层的方向上，所述第一活性材料层的尺寸为80mm-1000mm。
可选的，沿所述第一活性材料层至所述第二活性材料层的方向上，所述第二活性材料层的尺寸为10mm-30mm。
可选的，所述电极极片的面密度为150g/m2-600g/m2。
本申请提供的电极极片发生析锂现象的概率低，体积能量密度和质量能量密度高，提高了电极极片的循环稳定性，有利于提高电池的使用寿命。
第二方面，本申请提供了一种电池，所述电池包括正极极片和负极极片，以及设置在所述正极极片和所述负极极片之间的隔膜，所述负极极片包括第一方面所述的电极极片。
可选的，所述正极极片包括第一方面所述的电极极片。
本申请提供的电池，电化学性能优异，使用寿命长，产品竞争力强。
第三方面，本申请提供了一种用电设备，所述用电设备包括第二方面所述的电池。
本申请提供的用电设备综合性能优异，安全性能高，市场竞争力强。
附图说明
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍。此处所描述的具体实施例仅仅用以解释本发明，并不用于限定本发明。
图1为本申请一实施方式提供的电极极片的截面示意图。
图2为本申请另一实施方式提供的电极极片的截面示意图。
图3为本申请又一实施方式提供的电极极片的截面示意图。
附图标记说明：
100-电极极片；10-集流体；20-活性材料层；21-第一活性材料层；22-第二活性材料层；
11-极耳。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
请参阅图1，为本申请一实施方式提供的电极极片的截面示意图，电极极片100包括集流体10和设置在集流体10至少一侧表面的活性材料层20，活性材料层20包括第一活性材料层21和与第一活性材料层21同层设置且相连接的第二活性材料层22，沿第一活性材料层21至第二活性材料层22的方向上，第二活性材料层22的厚度逐渐减小，第一活性材料层21包括第一活性材料，第二活性材料层22包括第二活性材料，第一活性材料层21中的第一活性材料的质量含量小于第二活性材料层22中的第二活性材料层的质量含量。本申请提供的电极极片中通过控制第一活性材料层中的第一活性材料的质量含量与第二活性材料层中的第二活性材料层的质量含量的关系，使得第二活性材料层中离子嵌入位点数量增加，提高了第二活性材料层容量，进而提升了电极极片的容量、体积能量密度和重量能量密度，降低了电极极片在使用过程中发生析锂现象的概率，有利于提高电池的容量、循环稳定性和使用寿命。
在本申请一实施方式中，沿第一活性材料层至第二活性材料层的方向上(如图1中箭头所示的方向)，第二活性材料层的厚度逐渐减小。逐渐减小可以为线性减小，也可以为非线性减小，如梯度减小、抛物线状减小等。定义电极极片的活性材料层中厚度逐渐减小的区域为削薄区，厚度保持不变的区域为非削薄区。因此，第一活性材料层为非削薄区，第二活性材料层为削薄区，本申请通过提高削薄区中第二活性材料的含量，提高电极极片中削薄区的容量，提高电极极片的容量，缓解析锂现象，提高电极极片的能量密度。
在本申请中，电极极片中，集流体将化学能转为电能进行输出，提高电极极片的导电能力。集流体为正极集流体或负极集流体，电极极片为正极极片时，集流体为正极集流体，电极极片为负极极片时，集流体为负极集流体。在本申请一实施方式中，正极集流体可以但不限于为铜、铝、镍和不锈钢中的至少一种；负极集流体可以但不限于包括铜、铝、镍和不锈钢的至少一种。在本申请一实施例中，集流体为正极集流体时，电极极片为正极极片，集流体可以为铝箔。在本申请另一实施例中，集流体为负极集流体时，电极极片为负极极片，集流体可以为铜箔。
在本申请一实施方式中，活性材料层完全覆盖集流体的表面；即活性材料层在集流体表面的正投影完全覆盖集流体该表面。请参阅图2，为本申请另一实施方式提供的电极极片的截面示意图，电极极片100中，集流体10表面存在未被活性材料层20覆盖区域，集流体10中未被活性材料层20覆盖区域作为极耳11，极耳11的一端与第二活性材料层22(削薄区)相连，极耳11的另一端可以与外部设备连接，进行充放电循环过程。一些实施例中，第二活性材料层设置在第一活性材料层的一侧。具体的，当电极极片具有极耳时，第二活性材料层可以设置第一活性材料层与极耳之间。另一些实施例中，第二活性材料层设置在第一活性材料层的相对两侧。具体的，当电极极片具有极耳时，第二活性材料层可以设置第一活性材料层与极耳之间。
在本申请一实施方式中，如图1所示，电极极片100包括集流体10和设置在集流体10一侧表面的活性材料层20，活性材料层20包括第一活性材料层21和第二活性材料层22，第一活性材料层21和第二活性材料层22设置在集流体10的同一侧表面上。请参阅图3，为本申请又一实施方式提供的电极极片的截面示意图，电极极片100包括集流体10和设置在集流体10相对两侧表面的活性材料层20，可以进一步提高电极极片的能量密度，降低电极极片的析锂现象发生概率。在本申请中，第一活性材料可以为正极活性材料或负极活性材料，电极极片为正极极片时，第一活性材料为正极活性材料，电极极片为负极极片时，第一活性材料为负极活性材料。在本申请一实施方式中，正极活性材料可以但不限于包括钴酸锂材料、镍钴锰材料、镍钴铝材料、镍钴锰铝材料、磷酸铁锂材料、磷酸锰锂材料、磷酸钒锂材料、锰酸锂材料和富锂锰基材料中的至少一种；负极活性材料可以但不限于包括人造石墨、天然石墨、硬碳、软碳和石墨烯中的至少一种。在本申请一实施例中，第一活性材料为正极活性材料时，第一活性材料可以为磷酸铁锂材料。在本申请另一实施例中，第一活性材料为负极活性材料时，第一活性材料可以为人造石墨。
在本申请中，第二活性材料层包括第二活性材料，第二活性材料可以为正极活性材料或负极活性材料，电极极片为正极极片时，第二活性材料为正极活性材料，电极极片为负极极片时，第二活性材料为负极活性材料，可以提高电极极片的导电能力和能力密度。在本申请一实施方式中，正极活性材料可以但不限于包括钴酸锂材料、镍钴锰材料、镍钴铝材料、镍钴锰铝材料、磷酸铁锂材料、磷酸锰锂材料、磷酸钒锂材料、锰酸锂材料和富锂锰基材料中的至少一种；负极活性材料可以但不限于包括人造石墨、天然石墨、硬碳、软碳和石墨烯中的至少一种。在本申请一实施例中，第二活性材料为正极活性材料时，第二活性材料可以为磷酸铁锂材料。在本申请另一实施例中，第二活性材料为负极活性材料时，第二活性材料可以为人造石墨。
在本申请一实施方式中，第一活性材料层中第一活性材料的质量含量为93％-97.2％，可以提高电极极片的能量密度和导电能力。具体的，第一活性材料层中第一活性材料的质量含量可以但不限于为93％、94％、95％、96％、9.65％或97.2％等。在本申请一实施例中，第一活性材料为负极活性材料时，第一活性材料层中第一活性材料的质量含量可以为93％-97％，可以提高负极极片的能量密度。在本申请另一实施例中，第一活性材料为正极活性材料时，第一活性材料层中第一活性材料的质量含量可以为95％-97.2％，可以提高正极极片的能量密度。
在本申请一实施方式中，第二活性材料层中第二活性材料的质量含量为96.2％-98.5％，可以提高电极极片的能量密度和导电能力。具体的，第二活性材料层中第二活性材料的质量含量可以但不限于为96.2％、96.5％、96.8％、97％、9.75％或98.5％等。在本申请一实施例中，第二活性材料为负极活性材料时，第二活性材料层中第二活性材料的质量含量可以为96.2％-98.5％，可以提高负极极片的能量密度。在本申请另一实施例中，第二活性材料为正极活性材料时，第二活性材料层中第二活性材料的质量含量可以为97％-98.5％，可以提高正极极片的能量密度。
本申请中粒径D50为累计体积分布百分数达到50％时所对应的粒径。在本申请一实施方式中，第一活性材料的一次颗粒粒径D50小于第二活性材料的一次颗粒粒径D50。相同的活性材料质量下，活性材料的一次颗粒粒径D50越小，其比表面积越大，离子脱嵌位点越多，锂离子扩散距离越短，有利于提高其导电能力和比容量。由于第二活性材料层靠近极耳区域，充放电过程中温度升高，可以使用一次颗粒粒径大的活性材料，利用温度升高，其动力学性能提高的特性，提高第二活性材料层的导电能力，有利于提高电极极片的耐高温性能和使用寿命，降低电极极片的制备成本，避免电极极片使用过程中出现析锂现象。
在本申请一实施方式中，第一活性材料的碳包覆层的质量含量大于第二活性材料的碳包覆层的质量含量。碳包覆层的质量含量越高，包覆层越厚，可以提高活性材料的导电能力。由于第二活性材料层靠近极耳区域，充放电过程中温度升高，可以使用碳包覆层的质量含量小的活性材料，利用温度升高，其动力学性能提高的特性，保持第二活性材料层的高导电能力，提高电极极片的体积能量密度和重量能量密度，进而可以提高电池的热稳定性和安全性能，降低电池的热失控风险。
在本申请一实施方式中，第一活性材料的一次颗粒粒径D50为0.3μm-9μm。具体的，第一活性材料的一次颗粒粒径D50可以但不限于为0.3μm、1μm、2μm、4μm、6μm、8μm或9μm等。在本申请一实施例中，第一活性材料为负极活性材料时，第一活性材料的一次颗粒粒径D50可以为6μm-9μm。在本申请另一实施例中，第一活性材料为正极活性材料时，第一活性材料的一次颗粒粒径D50可以为0.3μm-1.3μm。
在本申请一实施方式中，第二活性材料的一次颗粒粒径D50为0.7μm-15μm。具体的，第二活性材料的一次颗粒粒径D50可以但不限于为0.7μm、1μm、2μm、8μm、10μm、13μm或15μm等。在本申请一实施例中，第二活性材料为负极活性材料时，第二活性材料的一次颗粒粒径D50可以为9μm-15μm。在本申请另一实施例中，第二活性材料为正极活性材料时，第二活性材料的一次颗粒的粒径可以为0.7μm-2μm。
在本申请一实施方式中，第一活性材料的碳包覆层的质量含量为0.5％-2％，碳包覆层的质量含量越高，说明活性材料表面包覆碳含量越多，碳层越厚。适量的碳包覆层的质量含量有利于提高活性材料的导电能力，提升电池的安全性能，降低电池的热失控风险。具体的，第一活性材料的碳包覆层的质量含量可以但不限于为0.5％、1％、1.2％、1.6％、1.8％或2％等。
在本申请一实施方式中，第二活性材料的碳包覆层的质量含量小于或等于0.5％。具体的，第二活性材料的碳包覆层的质量含量可以但不限于为小于或等于0.5％、小于或等于0.4％、小于或等于0.3％、小于或等于0.2％或小于或等于0.1％等。在本申请一实施例中，电极极片为负极极片时，第二活性材料的碳包覆层的质量含量可以为小于或等于0.5％。
在本申请一实施方式中，第一活性材料层中还包括第一导电剂和第一粘结剂，第一导电剂可以提高电极极片的导电能力，第一粘结剂可以提高第一活性材料层各组分之间和第一活性材料层和集流体之间的结合能力，有利于提高电极极片的力学性能。
第一导电剂可以为正极导电剂或负极导电剂，电极极片为正极极片时，第一导电剂为正极导电剂，电极极片为负极极片时，第一导电剂为负极导电剂，可以提高电极极片的导电能力。在本申请一实施方式中，正极导电剂可以但不限于包括碳纳米管、乙炔黑、石墨烯、导电石墨和炭黑中的至少一种；负极导电剂可以但不限于包括碳纳米管、乙炔黑、石墨烯、导电石墨和炭黑中的至少一种。在本申请一实施例中，第一导电剂为正极导电剂时，第一导电剂可以为碳纳米管。在本申请另一实施例中，第一导电剂为负极导电剂时，第一导电剂可以为碳黑。
在本申请一实施方式中，第一活性材料层中第一导电剂的质量含量为0.5％-2％，可以提高电极极片的导电能力。具体的，第一活性材料层中第一导电剂的质量含量可以但不限于为0.5％、0.8％、1％、1.5％、1.8％或2％等。在本申请一实施例中，第一导电剂为正极导电剂时，第一活性材料层中第一导电剂的质量含量可以为1％-2％。在本申请另一实施例中，第一导电剂为负极导电剂时，第一活性材料层中第一导电剂的质量含量可以为0.5％-2％。
第一粘结剂可以为正极粘结剂或负极粘结剂，电极极片为正极极片时，第一粘结剂为正极粘结剂，电极极片为负极极片时，第一粘结剂为负极粘结剂，可以提高电极极片的力学性能。在本申请一实施方式中，正极粘结剂可以但不限于包括聚偏氟乙烯、聚偏二氟乙烯、聚四氟乙烯、聚乙烯、聚丙烯、聚苯乙烯、聚丁二烯、丙烯酸树脂、环氧树脂、聚氧化乙烯、羧甲基纤维素钠和丁苯橡胶中的至少一种；负极粘结剂可以但不限于包括聚偏氟乙烯、聚偏二氟乙烯、聚四氟乙烯、聚乙烯、聚丙烯、聚苯乙烯、聚丁二烯、丙烯酸树脂、环氧树脂、聚氧化乙烯、羧甲基纤维素钠和丁苯橡胶中的至少一种。在本申请一实施例中，第一粘结剂为正极粘结剂时，第一粘结剂可以为聚偏氟乙烯。在本申请另一实施例中，第一粘结剂为负极粘结剂时，第一粘结剂可以为丁苯橡胶。
在本申请一实施方式中，第一活性材料层中第一粘结剂的质量含量为1％-3％，适宜的第一粘结剂可以提高电极极片的力学性能。具体的，第一活性材料层中第一粘结剂的质量含量可以但不限于为1％、1.2％、1.8％、2％、2.4％、2.6％、2.8％或3％等。在本申请一实施例中，第一粘结剂为正极粘结剂时，第一活性材料层中第一粘结剂的质量含量可以为1.8％-3％。在本申请另一实施例中，第一粘结剂为负极粘结剂时，第一活性材料层中第一粘结剂的质量含量可以为1％-2％。
在本申请一实施方式中，第二活性材料层中还包括第二导电剂和第二粘结剂，第二导电剂可以提高电极极片的导电能力，第二粘结剂可以提高第二活性材料层各组分之间和第二活性材料层和集流体之间的结合能力，有利于提高电极极片的力学性能。
第二导电剂可以为正极导电剂或负极导电剂，电极极片为正极极片时，第二导电剂为正极导电剂，电极极片为负极极片时，第二导电剂为负极导电剂，可以提高电极极片的导电能力。在本申请一实施方式中，正极导电剂可以但不限于包括碳纳米管、乙炔黑、石墨烯、导电石墨和炭黑中的至少一种；负极导电剂可以但不限于包括碳纳米管、乙炔黑、石墨烯、导电石墨和炭黑中的至少一种。在本申请一实施例中，第二导电剂为正极导电剂时，第二导电剂可以为导电石墨。在本申请另一实施例中，第二导电剂为负极导电剂时，第二导电剂可以为碳纳米管。
在本申请一实施方式中，第二活性材料层中第二导电剂的质量含量小于或等于1％，适当的第二导电剂质量可以减缓电极极片的析锂现象。具体的，第二活性材料层中第二导电剂的质量含量可以但不限于为小于或等于1％、小于或等于0.8％、小于或等于0.7％、小于或等于0.5％、小于或等于0.3％或小于或等于0.1％等。
第二粘结剂可以为正极粘结剂或负极粘结剂，电极极片为正极极片时，第二粘结剂为正极粘结剂，电极极片为负极极片时，第二粘结剂为负极粘结剂，可以提高电极极片的力学性能。在本申请一实施方式中，正极粘结剂可以但不限于包括聚偏氟乙烯、聚偏二氟乙烯、聚四氟乙烯、聚乙烯、聚丙烯、聚苯乙烯、聚丁二烯、丙烯酸树脂、环氧树脂、聚氧化乙烯、羧甲基纤维素钠和丁苯橡胶中的至少一种；负极粘结剂可以但不限于包括聚偏氟乙烯、聚偏二氟乙烯、聚四氟乙烯、聚乙烯、聚丙烯、聚苯乙烯、聚丁二烯、丙烯酸树脂、环氧树脂、聚氧化乙烯、羧甲基纤维素钠和丁苯橡胶中的至少一种。在本申请一实施例中，第二粘结剂为正极粘结剂时，第二粘结剂可以为聚偏氟乙烯。在本申请另一实施例中，第二粘结剂为负极粘结剂时，第二粘结剂可以为聚四氟乙烯。
在本申请一实施方式中，第二活性材料层中第二粘结剂的质量含量为0.5％-2％。具体的，第二活性材料层中第二粘结剂的质量含量可以但不限于为0.5％、0.8％、1％、1.2％、1.5％、1.8％或2％等。在本申请一实施例中，第二粘结剂为正极粘结剂时，第二活性材料层中第二粘结剂的质量含量可以为1.5％-2％。在本申请另一实施例中，第二粘结剂为负极粘结剂时，第二活性材料层中第二粘结剂的质量含量可以为0.5％-1.2％。
在本申请一实施方式中，第一活性材料层中第一导电剂的质量含量大于第二活性材料层中第二导电剂的质量含量。由于第二活性材料层靠近极耳区域，充放电过程中温度升高，利用温度升高，第二活性材料的动力学性能有所提升，可以保持第二活性材料层具有高的导电能力，从而可以减少导电剂的使用，减低电极极片的制备成本。
在本申请一实施方式中，第一活性材料中第一粘结剂的质量含量大于第二活性材料层中的第二粘结剂的质量含量。由于第二活性材料层中，第二导电剂的含量下降，其固含量有所降低，从而可以采用质量含量低的粘结剂，既可以实现第二活性材料和第二导电剂的分散，又不会不影响电极极片的力学性能，降低电极极片的制备成本，有利于电极极片的工业化应用。
在本申请一实施方式中，电极极片为负极极片时，第一活性材料层中还包括第一增稠剂，可以促进第一活性材料层均匀分布。具体的，第一增稠剂可以但不限于包括羧甲基纤维素钠或羧甲基纤维素锂等。在本申请一实施例中，第一增稠剂可以为羧甲基纤维素钠，此时负极粘结剂可以为丁苯橡胶。
在本申请一实施方式中，第一活性材料层中第一增稠剂的质量含量为1.5％-3％。具体的，第一活性材料层中第一增稠剂的质量含量可以但不限于为1.5％、1.8％、2％、2.2％、2.5％、2.7％、2.8％或3％等。在本申请一实施例中，第一活性材料层中第一增稠剂的质量含量可以为1.5％-2.5％。在本申请另一实施例中，第一活性材料层中第一增稠剂的质量含量可以为2％-3％。
在本申请一实施方式中，电极极片为负极极片时，第二活性材料层中还包括第二增稠剂，可以促进第二活性材料层均匀分布。具体的，第二增稠剂可以但不限于包括羧甲基纤维素钠或羧甲基纤维素锂等。在本申请一实施例中，第二增稠剂可以为羧甲基纤维素钠，此时负极粘结剂可以为丁苯橡胶。
在本申请一实施方式中，第二活性材料层中第二增稠剂的质量含量为1％-1.5％。具体的，第二活性材料层中第二增稠剂的质量含量可以但不限于为1％、1.2％、1.3％、1.4％或1.5％等。在本申请一实施例中，第二活性材料层中第二增稠剂的质量含量可以为1％-1.2％。在本申请另一实施例中，第二活性材料层中第二增稠剂的质量含量可以为1.2％-1.5％。
在本申请一实施方式中，第一活性材料层的厚度为92μm-300μm。具体的，第一活性材料层的厚度可以但不限于为92μm、100μm、150μm、200μm、250μm或300μm等。在本申请一实施例中，电极极片为正极极片时，第一活性材料层的厚度可以为130μm-300μm。在本申请另一实施例中，电极极片为负极极片时，第一活性材料的厚度可以为100μm-180μm。
在本申请一实施方式中，沿第二活性材料层至第一活性材料层的方向上，第一活性材料层的尺寸为80mm-1000mm。第一活性材料层的尺寸较大，有利于提高电极极片的能量密度。具体的，沿第二活性材料层至第一活性材料层的方向上，第一活性材料层的尺寸可以但不限于为80mm、100mm、200mm、400mm、600mm、800mm或1000mm等。在本申请一实施例中，沿第二活性材料层至第一活性材料层的方向上，第一活性材料层的尺寸可以为80mm-600mm。在本申请一另实施例中，沿第二活性材料层至第一活性材料层的方向上，第一活性材料层的尺寸可以为500mm-1000mm。
在本申请一实施方式中，第二活性材料层的最大厚度为92μm-300μm。具体的，第二活性材料层的最大厚度可以但不限于为92μm、100μm、120μm、150μm、180μm、220μm、250μm或300μm等。在本申请一实施例中，电极极片为正极极片时，第二活性材料层的最大厚度为120μm-270μm。在本申请另一实施例中，电极极片为负极极片时，第二活性材料层的最大厚度为92μm-165μm。一些实施例中，沿第一活性材料层至第二活性材料层的方向上，第二活性材料层的厚度由92μm-300μm逐渐减小为0μm。
在本申请一实施方式中，沿第一活性材料层至第二活性材料层的方向上，第二活性材料层的尺寸为10mm-30mm。第二活性材料层的尺寸较小，有利于降低电极极片的析锂现象。具体的，沿第一活性材料层至第二活性材料层的方向上，第二活性材料层的尺寸可以但不限于为10mm、15mm、20mm、25mm或30mm等。在本申请一实施例中，沿第一活性材料层至第二活性材料层的方向上，第二活性材料层的尺寸为10mm-20mm。在本申请另一实施例中，沿第一活性材料层至第二活性材料层的方向上，第二活性材料层的尺寸为15mm-30mm。
在本申请一实施方式中，电极极片的面密度为150g/m2-600g/m2，适宜的电极极片的面密度可以提高电极极片的能量密度，进而提高电池的容量，降低电池的内阻。现有制备工艺中，负极极片存在削薄区，而对应正极极片为正常涂覆区域，则导致削薄区的负极容量与正极容量的比值降低，出现严重的析锂现象，导致电池的寿命减短。相关技术中，通过提高负极极片整体面密度，提高负极极片的容量，但会增加负极极片的制备成本，降低负极极片的体积能量密度和质量能量密度。本申请提供的电极极片与相关技术中电极极片的面密度相当，在不改变电极极片面密度的情况下，通过控制第一活性材料层中第一活性材料和第二活性材料层中第二活性材料的关系，提高第二活性材料层(削薄区)的容量，进而提升电极极片的容量，改善析锂现象的同时，保持电极极片具有较高的体积能量密度和质量能量密度，降低电极极片的制备成本。具体的，电极极片的面密度可以但不限于为150g/m2、200g/m2、250g/m2、300g/m2、350g/m2、400g/m2、450g/m2、500g/m2、550g/m2或600g/m2等。在本申请一实施例中，电极极片为正极极片时，正极极片的面密度可以为300g/m2-600g/m2，其中第一活性材料层的面密度可以为300g/m2-600g/m2，第二活性材料层的面密度为276g/m2-599g/m2，沿第一活性材料层至第二活性材料层的方向上，第二活性材料层的面密度逐渐减小。在本申请另一实施例中，电极极片为负极极片时，负极极片的面密度可以为150g/m2-300g/m2，其中第一活性材料层的面密度可以为150g/m2-300g/m2，第二活性材料层的面密度为142g/m2-299g/m2，沿第一活性材料层至第二活性材料层的方向上，第二活性材料层的面密度逐渐减小。
本申请一实施方式提供了一种电极极片的制备方法，包括：
将第一浆料和第二浆料涂覆在集流体表面，第一浆料包括第一活性材料，第二浆料包括第二活性材料；经干燥后得到电极极片。本申请提供的制备方法新颖，制备流程简单，制备成本低，可以制得体积能量密度和重量能量密度高、不易发生析锂反应的电极极片。可以通过该制备方法制得上述任意一实施方式提供的电极极片。
在本申请一实施方式中，第一浆料还包括第一导电剂和第一粘结剂，第一活性材料、第一导电剂和第一粘结剂的质量比为(93-97.2):(0.5-2):(1-3)，适宜的第一浆料配比可以缓解电极极片的析锂现象，提高电极极片的能量密度。具体的，第一活性材料、第一导电剂和第一粘结剂的质量比可以但不限于为93:0.5:1、93.5:0.8:1.5、94:1:1.8、94.5:1.2:1.8、95:1.5:2、96:1.8:2.2、96.5:1.8:2.5、97:2:2.8或97.2:2:3等。在本申请一实施例中，第一活性材料、第一导电剂和第一粘结剂的质量比可以为(93-96):(0.5-1.5):(1-2.2)。在本申请另一实施例中，第一活性材料、第一导电剂和第一粘结剂的质量比可以为(95-97.2):(1-2):(2-3)。
在本申请一实施方式中，电极极片为负极极片时，第一浆料还包括增稠剂，第一活性材料、第一导电剂、第一粘结剂和第一增稠剂的质量比为(93-97.2):(0.5-2):(1-3):(1.5-3)，可以提高第一浆料的黏度，促进第一浆料的涂覆能力。具体的，第一活性材料、第一导电剂、第一粘结剂和第一增稠剂的质量比可以但不限于为93:0.5:1:1.5、93.5:0.8:1.5:1.8、94:1:1.8:1.9、94.5:1.2:1.8:2、95:1.5:2:2.2、96:1.8:2.2:2.5、96.5:1.8:2.5:2.8、97:2:2.8:2.9或97.2:2:3:3等。在本申请一实施例中，第一活性材料、第一导电剂、第一粘结剂和第一增稠剂的质量比可以为(93-96):(0.5-1):(1-1.8):(1.5-2.5)。在本申请另一实施例中，第一活性材料、第一导电剂、第一粘结剂和第一增稠剂的质量比可以为(95-97.2):(1-2):(1.5-3):(2-3)。
在本申请一实施方式中，第一浆料中还包括第一溶剂，第一浆料中第一溶剂的质量含量为20％-50％，第一溶剂可以提高第一浆料的涂覆能力，促进第一活性材料在第一活性材料层中的均匀分布。具体的，第一溶剂可以但不限于为N-甲基吡咯烷酮等；第一溶剂的质量含量可以但不限于为20％、25％、30％、35％、40％、45％或50％等。在本申请一实施例中，第一溶剂可以为N-甲基吡咯烷酮，第一浆料中第一溶剂的质量含量可以为20％-35％。
在本申请一实施方式中，第二浆料还包括第二导电剂和第二粘结剂，第二活性材料、第二导电剂和第二粘结剂的质量比为(96.2-98.5):(0-1):(0.5-2)，可以降低电极极片的析锂现象发生概率，提高电极极片的能量密度。具体的，第二活性材料、第二导电剂和第二粘结剂的质量比可以但不限于为96.2:0:0.5、96.5:0.1:0.7、96.8:0.3:0.8、97:0.5:1、97.5:0.7:1、97.8:0.8:1.5、98:0.8:1.8或98.5:1:2等。在本申请一实施例中，第二活性材料、第二导电剂和第二粘结剂的质量比可以为(96.2-97.5):(0-0.6):(0.5-1.5)。在本申请另一实施例中，第二活性材料、第二导电剂和第二粘结剂的质量比可以为(97-98.5):(0.4-1):(1-2)。
在本申请一实施方式中，电极极片为负极极片时，第二浆料还包括增稠剂，第二活性材料、第二导电剂、第二粘结剂和第二增稠剂的质量比为(96.2-98.5):(0-1):(0.5-2):(1-1.5)，可以提高第二浆料的黏度，促进第二浆料的涂覆能力。具体的，第二活性材料、第二导电剂、第二粘结剂和第二增稠剂的质量比可以但不限于为96.2:0:0.5:1、96.5:0.1:0.7:1.1、96.8:0.3:0.8:1.2、97:0.5:1:1.3、97.5:0.7:1:1.3、97.8:0.8:1.5:1.4、98:0.8:1.8:1.4或98.5:1:2:1.5等。在本申请一实施例中，第二活性材料、第二导电剂、第二粘结剂和第二增稠剂的质量比可以为(96.2-97.5):(0-0.6):(0.5-1.5):(1-1.3)。在本申请另一实施例中，第二活性材料、第二导电剂、第二粘结剂和第二增稠剂的质量比可以为(97-98.5):(0.5-1):(1-2):(1.2-1.5)。
在本申请一实施方式中，第二浆料中还包括第二溶剂，第二浆料中第二溶剂的质量含量为20％-50％，第二溶剂可以提高第二浆料的涂覆能力，促进第二活性材料在第二活性材料层中的均匀分布。具体的，第二溶剂可以但不限于为N-甲基吡咯烷酮等；第二浆料中第二溶剂的质量含量可以但不限于为20％、25％、30％、35％、40％、45％或50％等。在本申请一实施例中，第二溶剂可以为N-甲基吡咯烷酮，第二浆料中第二溶剂的质量含量可以为20％-35％。
本申请还提供了一种电池，包括正极极片和负极极片，以及设置在正极极片和负极极片之间的隔膜，负极极片包括上述任意一实施方式所述的电极极片或上述任意一实施方式所述的制备方法制得的电极极片。本申请提供的负极极片提高了负极极片削薄区的容量，提高了电池中负极极片和正极极片容量比值，降低了电极极片出现析锂现象的风险，有利于提高电极极片的电化学性能和使用寿命，有利于电池的工业化应用。
在本申请一实施方式中，正极极片包括上述任意一实施方式所述的电极极片或上述任意一实施方式所述的制备方法制得的电极极片。也就是说，正极极片和负极极片均为本申请提供的电极极片，负极极片包括负极集流体和设置在负极集流体表面的负极活性材料层，负极活性材料层包括第一负极活性材料层和第二负极活性材料层，沿第一负极活性材料层至第二负极活性材料层的方向上，第二负极活性材料层的厚度逐渐减小，第一负极活性材料层中第一负极活性材料的质量含量小于第二负极活性材料层中第二负极活性材料；正极极片包括正极集流体和设置在正极集流体表面的正极活性材料层，正极活性材料层包括第一正极活性材料层和第二正极活性材料层，沿第一正极活性材料层至第二正极活性材料层的方向上，第二正极活性材料层的厚度逐渐减小，第一正极活性材料层中第一正极活性材料的质量含量小于第二正极活性材料层中第二正极活性材料。正极极片和负极极片相对设置，其中正极极片的第一正极活性材料层与负极极片的第二负极活性材料层相对设置，正极极片的第二正极活性材料层与负极极片的第一负极活性材料层相对设置，有利于进一步缓解电池的析锂现象，提高电池的容量和循环稳定性。
在本申请一实施方式中，隔膜可以进行离子交换，构成完整的离子传导通路。具体的，隔膜可以但不限于织造膜、无纺布、微孔膜、复合膜、碾压膜或隔膜纸等。在本申请一实施方式中，电池还包括电解液。其中，至少部分正极极片以及至少部分负极极片浸润在电解液中。本申请电解液没有特殊限制，可以但不限于采用本领域中能够作为电池电解液的物质。
本申请还提供了一种用电设备，用电设备包括上述任意一实施方式所述的电池。本申请提供的用电设备能量密度高、安全性能高，市场竞争力强。用电设备包括手机、平板、手表、VR眼镜、车辆等。在本申请一实施例中，该电池可用于车辆中，可以提高车辆用电安全和充电速率，提高新能源汽车的广泛应用，有利于绿色环保环境的构建。在本申请另一实施例中，该电池还可以应用于手机中，可以降低电池的制备成本提高电池使用寿命和使用安全性。本申请的用电设备可以是指车辆、电子设备、储能系统等，上述电池可以是以单体电池、电池模组、电池包、电容器等形式设置在用电设备中。
下面通过具体的示例对本申请技术方案的效果做进一步的说明。
实施例1
(1)正极极片的制备：将第一正极活性材料(磷酸铁锂，一次颗粒粒径D50为0.4μm)、第一正极导电剂(炭黑)和第一正极粘结剂(聚偏氟乙烯)与第一溶剂(N-甲基吡咯烷酮)混合得到第一正极浆料，第一正极浆料的固体成分中第一正极活性材料的质量含量为96.5％，第一正极导电剂的质量含量为1％，第一正极粘结剂的质量含量为2.5％；
将第二正极活性材料(磷酸铁锂，一次颗粒粒径D50为0.8μm)、第二正极导电剂(炭黑)和第二正极粘结剂(聚偏氟乙烯)与第二溶剂(N-甲基吡咯烷酮)混合得到第二正极浆料，第二正极浆料的固体成分中第二正极活性材料的质量含量为97.7％，第二正极导电剂的质量含量为0.5％，第二正极粘结剂的质量含量为1.8％；
将第一正极浆料和第二正极浆料分别涂覆在正极集流体上，经干燥后得到正极极片；第一正极浆料形成第一正极活性材料层(非削薄区)，第一正极活性材料层的厚度为250μm，第一正极活性材料层的面密度为450g/m2，第二正极浆料形成第二正极活性材料层(削薄区)，沿第一正极活性材料层至第二正极活性材料层的方向上，第二正极活性材料层的厚度逐渐减小，第二正极活性材料层的厚度由250μm逐渐减小至230μm，第二正极活性材料层的面密度为420g/m2。
(2)负极极片的制备：
将第一负极活性材料(人造石墨，一次颗粒粒径D50为8μm)、第一负极导电剂(炭黑)、第一负极粘结剂(丁苯橡胶)和第一增稠剂(羧甲基纤维素钠)与第一溶剂(N-甲基吡咯烷酮)混合得到第一负极浆料，第一负极浆料的固体成分中第一负极活性材料的质量含量为96.1％，第一负极导电剂的质量含量为1％，第一负极粘结剂的质量含量为1.3％，第一增稠剂的质量含量为1.6％；
将第二负极活性材料(人造石墨，一次颗粒粒径D50为13μm)、第二负极粘结剂(丁苯橡胶)和第二增稠剂(羧甲基纤维素钠)与第二溶剂(N-甲基吡咯烷酮)混合得到第二负极浆料，第二负极浆料的固体成分中第二负极活性材料的质量含量为97.6％，第二负极粘结剂的质量含量为1.1％，第二增稠剂的质量含量为1.3％；
将第一负极浆料和第二负极浆料分别涂覆在负极集流体上，经干燥后得到负极极片；第一负极浆料形成第一负极活性材料层(非削薄区)，第一负极活性材料层的厚度为135μm，第一负极活性材料层的面密度为204g/m2，第二负极浆料形成第二负极活性材料层(削薄区)，沿第一负极活性材料层至第二负极活性材料层的方向上，第二负极活性材料层的厚度逐渐减小，第二负极活性材料层的厚度由135μm逐渐减小至125μm，第二负极活性材料层的面密度为190g/m2。
实施例2
与实施例1不同之处在于，第一负极浆料包括第一负极活性材料(人造石墨)、第一负极导电剂(炭黑)、第一负极粘结剂(丁苯橡胶)和第一增稠剂(羧甲基纤维素钠)，第一负极浆料的固体成分中第一负极活性材料的质量含量为93％，第一负极导电剂的质量含量为2％，第一负极粘结剂的质量含量为2％，第一增稠剂的质量含量为3％；
第二负极浆料包括第二负极活性材料(人造石墨)、第二负极导电剂(炭黑)、第二负极粘结剂(丁苯橡胶)和第二增稠剂(羧甲基纤维素钠)，第二负极浆料的固体成分中第二负极活性材料的质量含量为98.5％，第二负极导电剂的质量含量为0.1％，第二负极粘结剂的质量含量为0.4％，第二增稠剂的质量含量为1％。
实施例3
与实施例1不同之处在于，第一正极浆料包括第一正极活性材料(磷酸铁锂)、第一正极导电剂(炭黑)和第一正极粘结剂(聚偏氟乙烯)第一正极浆料的固体成分中第一正极活性材料的质量含量为92％，第一正极导电剂的质量含量为4％，第一正极粘结剂的质量含量为4％；
第二正极浆料包括第二正极活性材料(磷酸铁锂)、第二正极导电剂(炭黑)和第二正极粘结剂(聚偏氟乙烯)，第二正极浆料的固体成分中第二正极活性材料的质量含量为99％，第二正极导电剂的质量含量为0.5％，第二正极粘结剂的质量含量为0.5％。
实施例4
与实施例1不同之处在于，负极极片中，第一负极活性材料为天然石墨。
实施例5
与实施例1不同之处在于，第一负极浆料的固体成分中第一负极活性材料的质量含量为96％，第一负极导电剂的质量含量为0.6％，第一负极粘结剂的质量含量为1.8％，第一增稠剂的质量含量为1.6％；第二负极浆料的固体成分中第二负极活性材料的质量含量为96.8％，第二负极导电剂的质量含量为0.8％，第二负极粘结剂的质量含量为1.1％，第二增稠剂的质量含量为1.3％。
实施例6
与实施例1不同之处在于，第一负极浆料的固体成分中第一负极活性材料的质量含量为96.2％，第一负极导电剂的质量含量为1％，第一负极粘结剂的质量含量为1.2％，第一增稠剂的质量含量为1.6％；第二负极浆料的固体成分中第二负极活性材料的质量含量为96.3％，第二负极导电剂的质量含量为1％，第二负极粘结剂的质量含量为1.4％，第二增稠剂的质量含量为1.3％。
实施例7
与实施例1不同之处在于，第一负极浆料的固体成分中第一负极活性材料的质量含量为94％，第一负极导电剂的质量含量为3％，第一负极粘结剂的质量含量为1.3％，第一增稠剂的质量含量为1.6％；第二负极浆料的固体成分中第二负极活性材料的质量含量为96.1％，第二负极导电剂的质量含量为1.5％，第二负极粘结剂的质量含量为1.1％，第二增稠剂的质量含量为1.3％。
实施例8
与实施例1不同之处在于，第一负极浆料的固体成分中第一负极活性材料的质量含量为93.4％，第一负极导电剂的质量含量为1％，第一负极粘结剂的质量含量为4％，第一增稠剂的质量含量为1.6％；第二负极浆料的固体成分中第二负极活性材料的质量含量为94.7％，第二负极导电剂的质量含量为1％，第二负极粘结剂的质量含量为3％，第二增稠剂的质量含量为1.3％。
实施例9
与实施例1不同之处在于，正极极片由第二正极浆料涂覆在正极集流体上制备得到，正极极片非削薄区厚度为250μm，正极极片削薄区厚度由250μm逐渐减小至230μm。
实施例10
与实施例1不同之处在于，负极极片由第二负极浆料涂覆在负极集流体上制备得到，负极极片非削薄区厚度为135μm，负极极片削薄区厚度由135μm逐渐减小至125μm。
对比例1
与实施例9不同之处在于，负极极片由第二负极浆料涂覆在负极集流体上制备得到，负极极片非削薄区厚度为135μm，负极极片削薄区厚度由135μm逐渐减小至125μm。
对比例2
与实施例9不同之处在于，负极极片由第二负极浆料涂覆在负极集流体上制备得到，负极极片非削薄区厚度为135μm，负极极片削薄区厚度由135μm逐渐减小至125μm；正极极片由第一正极浆料涂覆在正极集流体上制备得到，正极极片非削薄区厚度为250μm，正极极片削薄区厚度由250μm逐渐减小至230μm。
对比例3
与实施例9不同之处在于，负极极片中，第一负极浆料形成第二负极活性材料层，第二负极浆料形成第一负极活性材料层。
性能检测
将上述实施例1-10和对比例1-3制得的负极极片、正极极片与隔膜层叠设置，与铝壳组装后经盖板焊接、套壳焊接、烘烤、注液、陈化、化成等工序得到电池。
将上述实施例1-10和对比例1-3制得的电池进行质量能量密度测试，测试过程：常温25℃条件下电池以1C恒流充电至3.8V，之后恒压充电至截止电流0.05C，电池充满电后，将电池在1/3C放电倍率下放电，计算电池在1/3C放电倍率下的能量，记录为电池能量，标记为W。同时称量电池重量，并记录，标记为M，质量能量密度(Wh/kg)＝W/M。测试结果如表1所示。
将上述实施例1-10和对比例1-3制得的电池进行体积能量密度测试，测试过程：常温25℃条件下电池以1C恒流充电至3.8V，之后恒压充电至截止电流0.05C，电池充满电后，将电池在1/3C放电倍率下放电，计算电池在1/3C放电倍率下的能量，记录为电池能量，标记为W。同时测量电池体积，并记录，标记为V，体积能量密度(Wh/L)＝W/V。测试结果如表1所示。
将上述实施例1-10和对比例1-3制得的电池进行循环测试，循环100圈后，拆解循环100圈的样本，并拍照观察记录负极极片界面。测试结果如表1所示。
将上述实施例1-10和对比例1-3制得的电池进行快充循环测试，测试过程：在常温25℃条件下搁置30min，以2.65C恒流充电至30％SOC，2C恒流充电至40％SOC，1.7C恒流充电至65％SOC，1.4C恒流充电至70％SOC，1.1C恒流充电至75％SOC，0.8C恒流充电至90％SOC,0.65C充电至95％SOC，0.3C恒流充电至100％SOC，静置30min，以1C放电倍率下放电，重复以上步骤，直至电池健康状态(SOH)为80％，记录快充循环次数。结果如表1所示。
表1性能测试结果
根据实施例1-10和对比例1-3可以看出，本申请提供的电极极片通过控制第一活性材料层中的第一活性材料的质量含量与第二活性材料层中的第二活性材料层的质量含量的关系，在不降低电极极片的体积能量密度和重量能量密度的前提下，降低了电极极片在使用过程中发生析锂现象的概率，有利于电池电化学性能的提高。根据实施例1和实施例2-8可以看出，适宜的活性材料、粘结剂和导电剂的含量，可以进一步提高电极极片的能量密度，降低电极极片发生析锂现象概率。根据实施例1和对比例1-3，可以看出本申请提供的电极极片通过改善第一活性材料和第二活性材料的质量关系，改善电极极片的析锂现象，电极极片具有良好的能量密度，有利于提高电池的综合性能。
以上所述是本申请的优选实施方式，但并不能因此而理解为对本申请范围的限制。应当指出，对于本技术领域的普通技术人员来说，在不脱离本申请原理的前提下，还可以做出若干改进和润饰，这些改进和润饰也视为本申请的保护范围。

Claims (13)

  1. 一种电极极片，其特征在于，所述电极极片包括集流体和设置在所述集流体至少一侧表面的活性材料层，所述活性材料层包括第一活性材料层和与所述第一活性材料层同层设置且相连接的第二活性材料层，沿所述第一活性材料层至所述第二活性材料层的方向上，所述第二活性材料层的厚度逐渐减小，所述第一活性材料层包括第一活性材料，所述第二活性材料层包括第二活性材料，所述第一活性材料层中的第一活性材料的质量含量小于所述第二活性材料层中的第二活性材料层的质量含量。
  2. 如权利要求1所述的电极极片，其特征在于，所述第二活性材料层设置在所述第一活性材料层的一侧，或所述第二活性材料层设置所述第一活性材料层的相对两侧。
  3. 如权利要求1所述的电极极片，其特征在于，所述第一活性材料层中，所述第一活性材料的质量含量为93％-97.2％；
    所述第二活性材料层中，所述第二活性材料的质量含量为96.2％-98.5％。
  4. 如权利要求1所述的电极极片，其特征在于，所述第一活性材料的一次颗粒粒径D50小于所述第二活性材料的一次颗粒粒径D50；
    和/或所述第一活性材料的碳包覆层的质量含量大于所述第二活性材料的碳包覆层的质量含量。
  5. 如权利要求4所述的电极极片，其特征在于，所述第一活性材料的一次颗粒粒径D50为0.3μm-9μm，所述第二活性材料的一次颗粒粒径D50为0.7μm-15μm；
    和/或，所述第一活性材料的碳包覆层的质量含量为0.5％-2％，所述第二活性材料的碳包覆层的质量含量小于或等于0.5％。
  6. 如权利要求1所述的电极极片，其特征在于，所述第一活性材料层还包括第一导电剂和第一粘结剂，所述第二活性材料层还包括第二导电剂和第二粘结剂；
    所述第一活性材料层中的所述第一导电剂的质量含量大于所述第二活性材料层中的所述第二导电剂的质量含量，和/或所述第一活性材料层中的第一粘结剂的质量含量大于所述第二活性材料层中的所述第二粘结剂的质量含量。
  7. 如权利要求6所述的电极极片，其特征在于，所述第一活性材料层中，所述第一导电剂的质量含量为0.5％-2％，所述第一粘结剂的质量含量为1％-3％；
    所述第二活性材料层中，所述第二导电剂的质量含量小于或等于1％，所述第二粘结剂的质量含量为0.5％-2％。
  8. 如权利要求1所述的电极极片，其特征在于，所述第一活性材料层的厚度为92μm-300μm，所述第二活性材料层的最大厚度为92μm-300μm。
  9. 如权利要求1所述的电极极片，其特征在于，沿所述第二活性材料层至所述第一活性材料层的方向上，所述第一活性材料层的尺寸为80mm-1000mm；
    沿所述第一活性材料层至所述第二活性材料层的方向上，所述第二活性材料层的尺寸为10mm-30mm。
  10. 如权利要求1所述的电极极片，其特征在于，所述电极极片的面密度为150g/m2-600g/m2。
  11. 一种电池，其特征在于，所述电池包括正极极片和负极极片，以及设置在所述正极极片和所述负极极片之间的隔膜，所述负极极片包括权利要求1-10任意一项所述的电极极片。
  12. 如权利要求11所述的电池，其特征在于，所述正极极片包括权利要求1-10任意一项所述的电极极片。
  13. 一种用电设备，其特征在于，所述用电设备包括权利要求11-12任意一项所述的电池。
PCT/CN2025/104308 2024-06-27 2025-06-27 电极极片、电池及用电设备 Pending WO2026002189A1 (zh)

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CN119833716B (zh) * 2024-12-19 2025-11-11 江苏时代新能源科技有限公司 电池单体及其制备方法、电池装置与用电装置

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113113610A (zh) * 2021-03-10 2021-07-13 欣旺达电动汽车电池有限公司 正极极片及其制备方法、锂离子电池
CN116259709A (zh) * 2023-01-09 2023-06-13 东莞维科电池有限公司 一种电池负极片及其制备方法和锂离子电池
WO2023197946A1 (zh) * 2022-04-14 2023-10-19 华为技术有限公司 正极极片、二次电池、电子设备和移动装置
CN117855460A (zh) * 2024-01-04 2024-04-09 合肥国轩高科动力能源有限公司 锂离子电池阳极极片和其制备方法、锂离子电池
CN118073524A (zh) * 2022-11-23 2024-05-24 比亚迪股份有限公司 负极极片及锂电池和用电设备
CN118136918A (zh) * 2024-01-18 2024-06-04 宁德新能源科技有限公司 一种二次电池和用电装置
CN118888693A (zh) * 2024-06-27 2024-11-01 比亚迪股份有限公司 电极极片、电池及用电设备

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024092500A1 (zh) * 2022-11-01 2024-05-10 宁德新能源科技有限公司 负极极片及其制备方法、电化学装置及电子装置
CN121983546A (zh) * 2023-11-13 2026-05-05 兰钧新能源科技有限公司 负极片、电池和电池包

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113113610A (zh) * 2021-03-10 2021-07-13 欣旺达电动汽车电池有限公司 正极极片及其制备方法、锂离子电池
WO2023197946A1 (zh) * 2022-04-14 2023-10-19 华为技术有限公司 正极极片、二次电池、电子设备和移动装置
CN118073524A (zh) * 2022-11-23 2024-05-24 比亚迪股份有限公司 负极极片及锂电池和用电设备
WO2024109904A1 (zh) * 2022-11-23 2024-05-30 比亚迪股份有限公司 负极极片及锂电池和用电设备
CN116259709A (zh) * 2023-01-09 2023-06-13 东莞维科电池有限公司 一种电池负极片及其制备方法和锂离子电池
CN117855460A (zh) * 2024-01-04 2024-04-09 合肥国轩高科动力能源有限公司 锂离子电池阳极极片和其制备方法、锂离子电池
CN118136918A (zh) * 2024-01-18 2024-06-04 宁德新能源科技有限公司 一种二次电池和用电装置
CN118888693A (zh) * 2024-06-27 2024-11-01 比亚迪股份有限公司 电极极片、电池及用电设备

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