WO2024001318A1 - 电池极片、极片组件、电池和用电设备 - Google Patents

电池极片、极片组件、电池和用电设备 Download PDF

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Publication number
WO2024001318A1
WO2024001318A1 PCT/CN2023/082735 CN2023082735W WO2024001318A1 WO 2024001318 A1 WO2024001318 A1 WO 2024001318A1 CN 2023082735 W CN2023082735 W CN 2023082735W WO 2024001318 A1 WO2024001318 A1 WO 2024001318A1
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WO
WIPO (PCT)
Prior art keywords
active material
material layer
coating
pole piece
battery
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Application number
PCT/CN2023/082735
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English (en)
French (fr)
Inventor
陈悦飞
蒋嘉丽
毛国安
曹俊琪
Original Assignee
宁德时代新能源科技股份有限公司
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Publication of WO2024001318A1 publication Critical patent/WO2024001318A1/zh

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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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the field of battery technology, and in particular to a battery pole piece, pole piece assembly, battery and electrical equipment.
  • Lithium-ion batteries have been widely used in mobile and portable appliances due to their high energy density, high average open circuit voltage and long cycle life.
  • the pole piece of a commercial lithium-ion battery contains a current collector and an active material layer, where the active material layer is a continuous and uniform coating.
  • Liquid absorption capacity is an important parameter that affects the performance of lithium-ion batteries.
  • the liquid absorption capacity of the battery is mainly limited by the liquid absorption capacity of the middle area of the pole piece. Since the middle area of the pole piece is responsible for most of the liquid absorption function, and the heat dissipation capacity of the middle area of the pole piece is poor, after the battery is used for a period of time, the attenuation speed of the middle area of the pole piece is higher than that of the top and the height direction of the pole piece. The decay rate of the bottom, thereby affecting the overall service life of the battery.
  • the purpose of this application is to provide a battery pole piece, pole piece assembly, Batteries and electrical equipment can effectively solve the problem that the attenuation speed in the middle area of the pole piece is higher than the attenuation speed at the top and bottom of the height direction of the pole piece.
  • a first aspect of this application discloses a battery pole piece, which includes:
  • a current collector at least one surface of the current collector is provided with a first coating area, the first coating area is provided with an active material layer, and the active material layer includes an active material layer from top to bottom along the height direction of the current collector.
  • the first active material layer, the second active material layer and the third active material layer are connected in sequence, wherein the decay speed of the active material of the second active material layer is smaller than that of the first active material layer and the third active material layer. The decay rate of the active material in any one of the active material layers.
  • the battery pole piece of the present application has a first active material layer, a second active material layer and a third active material layer connected in sequence from top to bottom in the height direction of the current collector, wherein the active material of the second active material layer
  • the decay speed is smaller than the decay speed of the active material in either the first active material layer and the third active material layer, which can reduce the decay speed of the second active material layer and offset the middle area of the battery pole piece which bears most of the absorption.
  • the decay rate caused by the liquid capacity and the decay rate caused by poor heat dissipation ability make the decay rate of the first active material layer, the second active material layer and the third active material layer basically the same, thereby improving the overall service life of the battery pole piece. , improve the overall service life of the battery.
  • the second active material layer includes one or more of a lithium iron phosphate layer, a lithium manganese iron phosphate layer, and a lithium titanate layer.
  • the composition material of any of the lithium iron phosphate layer, the lithium iron manganese phosphate layer and the lithium titanate layer has a slower decay rate than the general electrode material, thereby reducing the decay rate of the second active material layer and making the first active material layer
  • the attenuation speeds of the material layer, the second active material layer and the third active material layer are basically the same.
  • the first active material layer includes at least one of a nickel cobalt manganese layer and a lithium cobalt oxide layer; and/or the third active material layer includes a nickel cobalt manganese layer and a cobalt oxide layer. at least one of the lithium layers.
  • the constituent materials of any one of the nickel cobalt manganese layer and the lithium cobalt oxide layer have a high energy density, thereby ensuring the energy of the battery.
  • the attenuation of any one of the constituent materials of the nickel cobalt manganese layer and the lithium cobalt oxide layer is higher than the attenuation speed of any of the constituent materials of the lithium iron phosphate layer, the lithium iron manganese phosphate layer and the lithium titanate layer, thereby causing the attenuation of the first active material layer, the second active material layer and the third active material layer.
  • the speed is basically the same.
  • the average particle size of the active material of the second active material layer is smaller than the particles of the active material of any one of the first active material layer and the third active material layer. diameter average.
  • a small average particle size means that the gaps between the particles are small, thereby slowing down the infiltration rate of the electrolyte in the battery pole piece, reducing the liquid absorption capacity of the battery pole piece, and thereby reducing the attenuation speed of the second active material layer.
  • the average particle size size of the active material of the second active material layer is 100% to 120% of the average particle size size of the active material of the first active material layer; and /Or, the average particle size of the active material in the second active material layer is 100% to 120% of the average particle size of the active material in the third active material layer.
  • the average particle size of the active material in the second active material layer is set to be greater than the average particle size of the active material in the first active material layer, and/or the average particle size of the active material in the second active material layer is set to be greater than the average particle size of the active material in the first active material layer.
  • the value is greater than the average particle size setting of the active material of the third active material layer, and the difference range is within 20%.
  • the decay speed of the active material combined with the second active material layer is smaller than that of the first active material layer and the third active material layer.
  • the decay speed of the active material in any one of the material layers can also ensure that the decay speed of the first active material layer, the second active material layer and the third active material layer is basically the same.
  • a first boundary line is provided between the first active material layer and the second active material layer
  • a first boundary line is provided between the second active material layer and the third active material layer.
  • the second boundary line, the first boundary line and the second boundary line are respectively arranged parallel to both ends of the current collector in the height direction.
  • the second active material layer is disposed at a middle position in the height direction of the current collector, and the height dimension of the first active material layer is the height dimension of the first coating area.
  • 10% to 40% of the height dimension of the second active material layer is 20% to 80% of the height dimension of the first coating area
  • the height dimension of the third active material layer is 20% to 80% of the height dimension of the first coating area.
  • the height dimensions of the first active material layer, the second active material layer and the third active material layer are arranged according to the above ratio, which can ensure that the first active material layer, the second active material layer and the third active material layer are
  • the decay speed of the third active material layer is basically the same.
  • the height dimension of the first active material layer is 25% to 35% of the height dimension of the first coating area
  • the height dimension of the second active material layer is the first coating
  • the height dimension of the third active material layer is 40% to 50% of the height dimension of the first coating region
  • the height dimension of the third active material layer is 20% to 30% of the height dimension of the first coating region.
  • the arrangement ratio of the above height dimensions is the optimal arrangement ratio of the present application, so that the attenuation speeds of the first active material layer, the second active material layer and the third active material layer are basically the same.
  • the coating weight of the second active material layer is 50%-100% of the coating weight of the first active material layer
  • the coating weight of the third active material layer It is 80%-120% of the coating weight of the first active material layer.
  • the third active material layer is The first active material layer, the second active material layer and the third active material layer are arranged according to the above three weight ratios, which can ensure that the attenuation speeds of the first active material layer, the second active material layer and the third active material layer are basically the same.
  • the proportion of the coating weight of the first active material layer, the coating weight of the second active material layer, and the coating weight of the third active material layer is 90% to 90%. 110%: 60% ⁇ 80%: 90% ⁇ 110%.
  • the above-mentioned arrangement ratio of the coating weights is the optimal arrangement ratio, so that the attenuation speeds of the first active material layer, the second active material layer and the third active material layer are basically the same.
  • the coating thickness of the second active material layer is 90%-100% of the coating thickness of the first active material layer
  • the coating thickness of the third active material layer is 80%-110% of the coating thickness of the first active material layer
  • the compacted density of the second active material layer is less than either of the first active material layer and the third active material layer of compacted density.
  • the proportion and coating weight ratio are set so that the compacted density of the second active material layer is smaller than that of either the first active material layer and the third active material layer, which is beneficial to the preservation of the electrolyte and makes the second active material
  • the material of the layer expands less during discharge, reducing competition for the top and bottom to absorb electrolyte.
  • the coating thickness of the first active material layer, the coating thickness of the second active material layer, and the coating thickness of the third active material layer are consistent.
  • the coating thickness of the first active material layer, the coating thickness of the second active material layer, and the coating thickness of the third active material layer are consistent.
  • the current collector is also provided with a second coating area and a tab area, and the tab area, the second coating area and the first coating area are located along the The height direction of the current collector is arranged on the same surface sequentially from top to bottom, wherein the second coating area is connected to the first coating area, and the second coating area is partially connected to the tab area.
  • the second coating area is provided with an insulating material layer
  • the tab area includes a metal conductive plate, the metal conductive plate is connected to the current collector or the metal conductive plate is a part of the current collector .
  • the battery pole piece can be conductively connected to other components through the tab area, and a second coating area is provided between the tab area and the first coating area, wherein the second coating area is provided with an insulating material layer, and the second coating area The area and the tab area are partially overlapped, thereby isolating the tab area from the active material layer through the insulating material layer, and preventing the tab area from being electrically connected to the case after the battery pole piece and the case are assembled into a battery.
  • the height of the overlapping portion of the second coating area and the tab area is 4mm-16mm, and the height of the second coating area is removed from the overlapping portion of the tab area. Size is 0.5mm-4mm.
  • the second aspect of the present application proposes an electrode assembly.
  • the electrode assembly includes a cathode sheet, an anode sheet, and a separation film disposed between the cathode sheet and the anode sheet, wherein the cathode sheet is any of the above.
  • the electrode assembly of the present application has the same technical features as any of the above-mentioned battery pole pieces and can achieve the same technical effects, they will not be described again here.
  • At least one surface of the anode sheet is provided with a third coating area disposed directly opposite the first coating area, and both ends of the anode sheet respectively exceed the third coating area.
  • a coating area is provided at both ends.
  • the third coating area includes a fourth active material layer, a fifth active material layer and a sixth active material layer connected in sequence from top to bottom along the height direction of the third coating area.
  • Material layer wherein the ratio of the coating weight of the fourth active material layer, the fifth active material layer, and the sixth active material layer to the first active material layer, the second active material layer The ratio of the coating weight of the third active material layer is consistent with that of the fourth active material layer and the fifth active material layer.
  • the ratio of the coating thickness of the sixth active material layer is consistent with the ratio of the coating thickness of the first active material layer, the second active material layer and the third active material layer, and/or , the height dimension of the fourth active material layer is 100%-140% of the height dimension of the first active material layer, and the height dimension of the fifth active material layer is the height dimension of the second active material layer 20%-100% of the height dimension of the sixth active material layer is 100%-140% of the height dimension of the third active material layer.
  • Arranging the fourth active material layer, the fifth active material layer and the sixth active material layer according to the above-mentioned coating weight, and/or coating thickness, and/or height size ratio can effectively reduce the damage in the middle area of the anode sheet.
  • the attenuation speed ensures that the attenuation speed of each active material layer along the height direction of the anode sheet is basically the same, thereby cooperating with the cathode sheet to jointly improve the service life of the battery.
  • the coating thickness of the fifth active material layer is 50%-99% of the coating thickness of the fourth active material layer, and/or, the fifth active material layer
  • the coating thickness is 50%-99% of the coating thickness of the sixth active material layer.
  • the fourth active material layer, the fifth active material layer and the sixth active material layer are arranged according to the above coating thickness ratio, and under the condition that the attenuation speed of each active material layer along the height direction of the anode sheet can be ensured to be basically the same, the reduction
  • the use of active materials in the fifth active material layer further reduces the manufacturing cost of the pole piece assembly and avoids waste of resources.
  • a third aspect of the present application proposes a battery including the electrode assembly described in any one of the above.
  • a fourth aspect of the present application provides an electrical device, which includes the above-mentioned battery, and the battery is used to provide electrical energy.
  • Figure 1 is a schematic structural diagram of a vehicle provided by an embodiment of the present application.
  • FIG. 2 is a schematic structural diagram of a battery pack provided by an embodiment of the present application.
  • FIG. 3 is a schematic structural diagram of a battery module provided by an embodiment of the present application.
  • Figure 4 is a schematic diagram of the exploded structure of a battery cell provided by an embodiment of the present application.
  • FIG. 5 is a schematic structural diagram of a battery pole piece provided by an embodiment of the present application.
  • FIG. 6 is a schematic structural diagram of an electrode assembly provided by an embodiment of the present application.
  • Figure 7 is a schematic structural diagram of an electrode assembly provided by another embodiment of the present application.
  • the reference numbers in the specific implementation are as follows: 1: Vehicle; 10: Battery, 11: Controller, 12: Motor; 20: Battery module, 21: Battery cell, 211: End cover, 212: Case, 213: Electrode assembly, 214: Electrode terminal; 30: Box, 301: First part, 302: Second part; 40: battery pole piece, 41: first coating area, 411: first active material layer, 412: second active material layer, 413: third active material layer, 42: second coating area, 43: tab district; 50: anode sheet, 51: third coating area, 511: fourth coating area, 512: fifth coating area, 513: The sixth coating area.
  • a first feature "on” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features may be in direct contact. Indirect contact through intermediaries.
  • the terms “above”, “above” and “above” the first feature is above the second feature may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is higher in level than the second feature.
  • "Below”, “below” and “beneath” the first feature to the second feature may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature has a smaller horizontal height than the second feature.
  • Power batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but are also widely used in electric vehicles such as electric bicycles, electric motorcycles and electric cars, as well as in many fields such as military equipment and aerospace.
  • Lithium-ion batteries have been widely used in mobile and portable appliances due to their high energy density, high average open circuit voltage and long cycle life.
  • the pole pieces of commercial lithium-ion batteries contain current collectors and active materials. material layer, wherein the active material layer is a continuous and uniform coating.
  • the liquid absorption capacity is an important parameter affecting the performance of lithium-ion batteries, and the liquid absorption capacity of the battery is mainly limited by the liquid absorption capacity of the middle region of the pole piece. Since the middle area of the pole piece is responsible for most of the liquid absorption function, and the heat dissipation capacity of the middle area of the pole piece is poor, after the battery is used for a period of time, the attenuation speed of the middle area of the pole piece is higher than that of the top and the height direction of the pole piece. The decay rate of the bottom, thereby affecting the overall service life of the battery.
  • the applicant found that by setting different electrodes along the height direction of the pole piece, active material, and make the attenuation speed of the active material in the middle area of the pole piece smaller than the attenuation speed at the top and bottom of the pole piece in the height direction, which can effectively ensure that the attenuation speed of the pole piece at each position along the height direction is basically the same, thereby improving the battery overall service life.
  • the inventor has designed a battery pole piece after in-depth research.
  • the first active material layer, the second active material layer and the third active material layer are sequentially connected from top to bottom in the height direction of the current collector of the battery pole piece.
  • the attenuation speeds of the second active material layer and the third active material layer are basically the same, thereby increasing the overall service life of the battery pole piece and improving the overall service life of the battery.
  • the present application provides a battery pole piece, a pole piece assembly including the battery pole piece, a battery, and electrical equipment using the battery.
  • This battery pole piece and pole piece assembly can be applied to any battery, such as battery cells, battery modules and battery packs, or primary batteries and secondary batteries.
  • This kind of battery is suitable for various electrical devices that use batteries, such as mobile phones, portable devices, laptops, battery cars, electric toys, power tools, electric vehicles, ships and spacecraft, etc.
  • spacecraft include aircraft, rockets, aerospace Aircrafts and spacecrafts, etc.; batteries are used to provide electrical energy for the above electrical equipment.
  • Vehicle 1 can be a fuel vehicle, a gas vehicle, or a new energy vehicle.
  • the new energy vehicle can be a pure electric vehicle, a hybrid vehicle, or a hybrid vehicle. Hybrid vehicles or extended-range vehicles, etc.
  • the battery 10 is disposed inside the vehicle 1 , and the battery 10 can be disposed at the bottom, head, or tail of the vehicle 1 .
  • the battery 10 may be used to power the vehicle 1 , for example, the battery 10 may serve as an operating power source for the vehicle 1 .
  • the vehicle 1 may also include a controller 11 and a motor 12 .
  • the controller 11 is used to control the battery 10 to provide power to the motor 12 , for example, for starting, navigating, and driving the vehicle 1 to meet its power requirements.
  • the battery 10 can not only be used as an operating power source of the vehicle 1 , but also can be used as a driving power source of the vehicle 1 , replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1 .
  • the battery 10 may include multiple battery cells 21 , where the battery cells 21 refer to the smallest unit that constitutes the battery module 20 or the battery pack. Multiple battery cells 21 may be connected in series and/or in parallel via electrode terminals to be used in various applications.
  • the battery mentioned in this application includes a battery module 20 or a battery pack. Among them, the plurality of battery cells 21 can be connected in series, in parallel, or in mixed connection. Mixed connection refers to a mixture of series connection and parallel connection.
  • the battery 10 may also be called a battery pack. In the embodiment of the present application, multiple battery cells 21 can directly form a battery pack, or they can first form a battery module 20, and then the battery module 20 can form a battery pack.
  • FIG. 2 shows a schematic structural diagram of a battery 10 according to an embodiment of the present application.
  • FIG. 3 shows a schematic structural diagram of a battery module 20 according to an embodiment of the present application.
  • the battery 10 may include a plurality of battery modules 20 and a case 30 , and the plurality of battery modules 20 are accommodated inside the case 30 .
  • the box 30 is used to accommodate the battery cells 21 or the battery modules 20 to prevent liquid or other foreign matter from affecting the charging or discharging of the battery cells 21 .
  • the box 30 may be a single cuboid, a simple three-dimensional structure such as a cylinder or a sphere, or a complex three-dimensional structure composed of a combination of simple three-dimensional structures such as a cuboid, a cylinder or a sphere.
  • the embodiments of the present application are not limited to this.
  • the material of the box body 30 can be alloy materials such as aluminum alloy, iron alloy, etc., or polymer materials such as polycarbonate, polyisocyanurate foam, or composite materials such as glass fiber and epoxy resin. The embodiment of the present application is not limited to this.
  • the box 30 may include a first part 301 and a second part 302.
  • the first part 301 and the second part 302 cover each other.
  • the first part 301 and the second part 302 jointly define a space for accommodating the battery cell 21. Space.
  • the second part 302 may be a hollow structure with one end open, and the first part 301 may be a plate-like structure.
  • the first part 301 covers the open side of the second part 302 so that the first part 301 can have a plate-like structure.
  • the part 301 and the second part 302 jointly define a space for accommodating the battery cells 21; the first part 301 and the second part 302 may also be hollow structures with one side open, and the open side of the first part 301 is covered with the second part.
  • the battery module 20 may include a plurality of battery cells 21 .
  • the plurality of battery cells 21 may be first connected in series, parallel, or mixed to form the battery module 20 .
  • the plurality of battery modules 20 may then be connected in series, parallel, or mixed to form the battery 10 .
  • the battery cell 21 may be in the shape of a cylinder, a flat body, a rectangular parallelepiped or other shapes, and the embodiments of the present application are not limited thereto.
  • Battery cells 21 are generally divided into three types according to packaging methods: cylindrical battery cells 21, rectangular battery cells 21 and soft-pack battery cells 21, and the embodiment of the present application is not limited to this. However, for the sake of simplicity of description, the following embodiments will be described using a lithium-ion battery cell 21 having a square shape as an example.
  • FIG. 4 is a schematic diagram of the exploded structure of the battery cell 21 provided in some embodiments of the present application.
  • the battery cell 21 refers to the smallest unit that constitutes the battery 10 .
  • the battery cell 21 includes an end cover 211 , a case 212 and an electrode assembly 213 .
  • the end cap 211 refers to a component that covers the opening of the housing 212 to isolate the internal environment of the battery cell 21 from the external environment.
  • the shape of the end cap 211 may be adapted to the shape of the housing 212 to fit the housing 212 .
  • the end cap 211 can be made of a material with a certain hardness and strength (such as aluminum alloy). In this way, the end cap 211 is less likely to deform when subjected to extrusion and collision, so that the battery cell 21 can have higher durability. Structural strength and safety performance can also be improved.
  • Functional components such as electrode terminals 214 may be provided on the end cap 211 .
  • the electrode terminal 214 may be used to electrically connect with the electrode assembly 213 for outputting or inputting electrical energy of the battery cell 21 .
  • the end cap 211 may also be provided with a pressure relief mechanism for releasing the internal pressure when the internal pressure or temperature of the battery cell 21 reaches a threshold.
  • an insulating member may be provided inside the end cover 211 , and the insulating member may be used to isolate the electrical connection components in the housing 212 from the end cover 211 to reduce the risk of short circuit.
  • the insulating member may be plastic, rubber, etc.
  • the housing 212 is a component used to cooperate with the end cover 211 to form an internal environment of the battery cell 21 , wherein the formed internal environment can be used to accommodate the electrode assembly 213 , electrolyte (not shown in the figure) and other components.
  • the housing 212 and the end cover 211 may be independent components, and an opening may be provided on the housing 212.
  • the end cover 211 covers the opening at the opening to form the internal environment of the battery cell 21.
  • the end cover 211 and the housing 212 can also be integrated.
  • the end cover 211 and the housing 212 can be integrated with other components. Before inserting into the shell, a common connection surface is formed.
  • the housing 212 may be of various shapes and sizes, such as rectangular parallelepiped, cylinder, hexagonal prism, etc. Specifically, the shape of the housing 212 can be determined according to the specific shape and size of the electrode assembly 213 .
  • the housing 212 may be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which are not specifically limited in the embodiment of the present application.
  • the electrode assembly 213 is a component in the battery cell 21 where electrochemical reactions occur.
  • One or more electrode assemblies 213 may be contained within the housing 212 .
  • the electrode assembly 213 is mainly formed by winding or stacking positive electrode sheets and negative electrode sheets, and usually a separator is provided between the positive electrode sheets and the negative electrode sheets.
  • the portions of the positive electrode sheet and the negative electrode sheet that contain active material constitute the main body of the electrode assembly 213, and the portions of the positive electrode sheet and the negative electrode sheet that do not contain active material each constitute tabs (not shown in the figure).
  • the positive electrode tab and the negative electrode tab can be located together at one end of the main body or respectively located at both ends of the main body.
  • the positive active material and the negative active material react with the electrolyte, and the tabs are connected to the electrode terminals 214 to form a current loop.
  • FIG. 5 is a schematic structural diagram of a battery pole piece 40 provided by an embodiment of the present application.
  • the battery pole piece 40 of the present application includes a current collector. At least one surface of the current collector is provided with a first coating area 41.
  • the first coating area 41 is provided with an active material layer.
  • the active material layer includes The first active material layer 411, the second active material layer 412 and the third active material layer 413 are connected in sequence from top to bottom in the height direction of the fluid, wherein the decay speed of the active material of the second active material layer 412 is smaller than that of the first active material layer 411. The decay speed of the active material in any one of the material layer 411 and the third active material layer 413.
  • the current collector in this application refers to a structure or part that collects current. Its function is mainly to collect the current generated by the active material of the battery in order to form a larger current for external output. In lithium-ion batteries, it mainly refers to metal foil. , such as copper foil and aluminum foil.
  • the coating area refers to the area on the current collector used for coating materials.
  • the current collector also includes areas that do not need to be coated, such as the location of the tabs on the current collector.
  • the first coating zone 41 of the present application is used for coating active materials.
  • the active material layer refers to a layered structure composed of active materials coated on the current collector.
  • the height direction of the current collector is the height direction of the battery pole piece 40, as shown in the arrow direction in Figure 5. It is also the height direction of the electrode assembly 213 after the battery pole piece 40 forms the electrode assembly 213 as shown in FIG. 4 .
  • the width direction of the battery pole pieces 40 is the height direction of the battery pole pieces 440 after forming the electrode assembly 213 .
  • connection arrangement means that two adjacent active material layers are connected and arranged without overlapping areas.
  • the decay rate of an active material refers to the rate at which the active material loses its ability to react with the electrolyte.
  • the battery electrode sheet 40 is a cathode sheet, and the current collector of the cathode sheet is an aluminum foil.
  • the first active material layer 411 and the third active material layer 411 are provided on one or both sides of the aluminum foil by coating.
  • the battery pole piece 40 of the present application has a first active material layer 411, a second active material layer 412 and a third active material layer 413 connected in sequence from top to bottom in the height direction of the current collector, wherein the second active material layer
  • the decay speed of the active material of the layer 412 is smaller than the decay speed of the active material of any one of the first active material layer 411 and the third active material layer 413, so that the decay speed of the second active material layer 412 can be reduced and the battery electrode piece can be reduced.
  • the attenuation speed caused by the middle region of 40 bearing most of the liquid absorbing capacity and the attenuation speed caused by poor heat dissipation capacity causes the attenuation of the first active material layer 411, the second active material layer 412 and the third active material layer 413.
  • the speed is basically the same, thereby ensuring the overall service life of the battery pole piece 40 and improving the overall service life of the battery.
  • the second active material layer 412 includes one or more of a lithium iron phosphate layer, a lithium iron manganese phosphate layer, and a lithium titanate layer.
  • the main active material of the lithium iron phosphate layer includes lithium iron phosphate
  • the main active material of the lithium iron manganese phosphate layer includes lithium iron manganese phosphate
  • the main active material of the lithium titanate layer includes lithium titanate.
  • the above lithium iron phosphate, One or more active materials of lithium iron manganese phosphate and lithium titanate are made into a slurry and applied to the middle position in the height direction of the current collector, thereby forming the second active material layer 412 .
  • lithium iron phosphate, lithium iron manganese phosphate and lithium titanate all have high stability and service life, and have a slower decay rate than ordinary electrode materials, thereby reducing the decay rate of the second active material layer 412 and offsetting the
  • the middle region of the pole piece bears most of the attenuation speed caused by the liquid absorption capacity and the attenuation speed caused by poor heat dissipation ability, thus causing the first active material layer 411, the second active material layer 412 and the third active material layer 413 to The decay speed is basically the same.
  • the first active material layer 411 includes at least one of a nickel cobalt manganese layer and a lithium cobalt oxide layer; and/or the third active material layer 413 includes nickel cobalt manganese. at least one of the lithium cobalt oxide layer and the lithium cobalt oxide layer.
  • the main active material of the nickel cobalt manganese layer includes nickel cobalt manganese
  • the main active material of the lithium cobalt oxide layer includes lithium cobalt oxide.
  • One or two active materials in the nickel cobalt manganese and lithium cobalt oxide are made into a slurry. And coated on the upper connection position of the second active material layer 412, thereby forming the first active material layer 411.
  • One or two active materials of nickel cobalt manganese and lithium cobalt oxide are made into a slurry and coated at the lower connection position of the second active material layer 412 to form the third active material layer 413 .
  • nickel cobalt manganese and lithium cobalt oxide both have high energy density, thus ensuring the energy of the battery.
  • the decay speed of nickel cobalt manganese and lithium cobalt oxide is higher than that of lithium iron phosphate, lithium iron manganese phosphate and lithium titanate.
  • the decay rate of The decay speeds of the layer 412 and the third active material layer 413 are substantially the same.
  • the average particle size size of the active material of the second active material layer 412 is smaller than the active material of any one of the first active material layer 411 and the third active material layer 413 average particle size.
  • the size of particles is called “grain size”, also known as “particle size” or “diameter”.
  • particle size also known as “particle size” or “diameter”.
  • the diameter (or combination) of the sphere is used as the equivalent particle diameter (or particle size) of the measured particle. distributed).
  • the average particle size size of the active material in the second active material layer 412 is smaller than the average particle size size of the active material in the first active material layer 411 , and at the same time, the average particle size size of the active material in the second active material layer 412 is smaller than The average particle size of the active material of the third active material layer 413 .
  • a small average particle size means that the gaps between the particles are small, thereby slowing down the infiltration rate of the electrolyte in the battery pole piece 40 and reducing the liquid absorption capacity of the battery pole piece 40 . If the average particle size of the active material in the second active material layer 412 is smaller than the average particle size of the active material in any one of the first active material layer 411 and the third active material layer 413 , the second active material layer 412 can be effectively reduced. The liquid absorbing ability of the active material layer 412 further reduces the decay speed of the second active material layer 412 .
  • the active material of the second active material layer 412 The average particle size is 100% to 120% of the average particle size of the active material of the first active material layer 411, and/or the average particle size of the active material of the second active material layer 412 is The average particle size of the active materials in the three active material layers 413 is 100% to 120%.
  • the average particle size of the active material in the second active material layer 412 is 100% to 120% of the average particle size of the active material in the first active material layer 411 , and at the same time, the activity of the second active material layer 412 is The average particle size of the material is 100% to 120% of the average particle size of the active material of the third active material layer 413 .
  • the average particle size of the active material in the second active material layer 412 is 100% to 120% of the average particle size of the active material in the first active material layer 411.
  • the activity of the second active material layer 412 is The average particle size of the material is smaller than the average particle size of the active material of the third active material layer 413 .
  • the average particle size of the active material in the second active material layer 412 is smaller than the average particle size of the active material in the first active material layer 411 , and at the same time, the average particle size of the active material in the second active material layer 412 is smaller than the average particle size of the active material in the first active material layer 411 .
  • the value is 100% to 120% of the average particle size of the active material of the third active material layer 413 .
  • the average particle size of the active material of the second active material layer 412 is set to be larger than the average particle size of the active material of the first active material layer 411 , and/or the particle size of the active material of the second active material layer 412 is set to be larger than the average particle size of the active material of the first active material layer 411 .
  • the average diameter size is set to be greater than the average particle size size of the active material of the third active material layer 413, and the difference range is within 20%.
  • the decay speed of the active material combined with the second active material layer 412 is smaller than that of the first active material.
  • the decay speed of the active material of the layer 411 and the decay speed of the active material of the third active material layer 413 can also ensure that the decay speed of the first active material layer 411, the second active material layer 412 and the third active material layer 413 is basically the same. consistent.
  • a first boundary line K1 is provided between the first active material layer 411 and the second active material layer 412, and the second active material layer 412 and the third active material layer 413 are A second boundary line K2 is provided in between.
  • the first boundary line K1 and the second boundary line K2 are respectively arranged parallel to the two ends in the height direction of the current collector.
  • the first boundary line is K1, which is the separation line between the first active material layer 411 and the second active material layer 412 in the first coating area 41
  • the second boundary line is K2, which is the separation line between the second active material layer 412 and the second active material layer 412.
  • the third active material layer 413 is at the dividing line of the first coating area 41 .
  • the first boundary line is K1 and the second boundary line is K2 respectively.
  • the two ends in the height direction of the current collector are arranged in parallel, thereby dividing the first active material layer 411, the second active material layer 412 and the third active material layer 413 into a rectangular structure arranged in contact, thereby ensuring that there is a rectangular structure along the same height direction of the current collector.
  • the same active material layer, so that the attenuation speeds of the first active material layer 411 , the second active material layer 412 and the third active material layer 413 are basically the same.
  • the second active material layer 412 is located at the middle position in the height direction of the current collector, and the height dimension L1 of the first active material layer 411 is the height dimension L1 of the first coating area 41 10% to 40% of the height dimension, the height dimension L2 of the second active material layer 412 is 20% to 80% of the height dimension of the first coating area 41, and the height dimension L3 of the third active material layer 413 is 20% to 80% of the height dimension of the first coating area 413. 10% to 40% of the height dimension of the cloth area 41.
  • the height dimension of the active material layer is the dimension of the active material layer in the height direction of the first coating area 41
  • the height direction of the first coating area 41 is the height direction of the current collector, as shown by the arrow in FIG. 5 direction shown.
  • the height dimension of the first coating area is the sum of the height dimension L1 of the first active material layer 411 , the height dimension L2 of the second active material layer 412 , and the height dimension L3 of the third active material layer 413 .
  • the second active material layer 412 and the third active material layer 413 are arranged along the height direction of the first coating area 41, and the second active material layer 412 occupies the middle position of the current collector, it assumes Most of the liquid absorbing capacity, therefore the second active material layer 412 occupies a large proportion of height.
  • the height dimensions of the first active material layer 411, the second active material layer 412 and the third active material layer 413 are arranged according to the above proportion, which can ensure that the first active material layer 411, the third active material layer 411 and the third active material layer 413 are
  • the attenuation speeds of the second active material layer 412 and the third active material layer 413 are basically the same.
  • the height L1 of the first active material layer 411 is 25% to 35% of the height of the first coating area 41
  • the height of the second active material layer 412 is
  • the size L2 is 40% to 50% of the height of the first coating area 41
  • the height L3 of the third active material layer 413 is 20% to 30% of the height of the first coating area.
  • the height dimension L1 of the first active material layer 411 is 30% of the height dimension of the first coating area 41
  • the height dimension L2 of the second active material layer 412 is 45% of the height dimension of the first coating area 41
  • the height dimension L3 of the third active material layer 413 is 25% of the height dimension of the first coating area.
  • the arrangement ratio of the above height dimensions is only one of the best arrangement ratios in the embodiment of the present application, so that The attenuation speeds of the first active material layer 411, the second active material layer 412 and the third active material layer 413 are made to be substantially consistent.
  • the coating weight of the second active material layer 412 is 50%-100% of the coating weight of the first active material layer 411
  • the coating weight of the third active material layer 413 is The coating weight is 80%-120% of the coating weight of the first active material layer 411.
  • the coating weight refers to the total weight of the active materials in the corresponding active material layer.
  • the total weight of the active materials corresponding to the second active material layer 412 is 50%-100% of the total weight of the active materials corresponding to the first active material layer 411
  • the total weight of the active materials corresponding to the third active material layer 413 is The first active material layer 411 corresponds to 80%-120% of the total weight of the active materials.
  • the arrangement ratio of the first active material layer 411, the second active material layer 412 and the third active material layer 413 is arranged according to the above three weight ratios, which can ensure that the first active material layer 411, the second active material layer 412 and The decay speed of the third active material layer 413 is basically the same.
  • the ratio of the coating weight of the first active material layer 411 , the coating weight of the second active material layer 412 and the coating weight of the third active material layer 413 is 90% ⁇ 110%: 60% ⁇ 80%: 90% ⁇ 110%.
  • the ratio of the coating weight of the first active material layer 411, the coating weight of the second active material layer 412, and the coating weight of the third active material layer 413 is 100%:70%:100%.
  • the above arrangement ratio of the coating weight is one of the best arrangement ratios in the embodiment of the present application, so that the attenuation speeds of the first active material layer 411 , the second active material layer 412 and the third active material layer 413 are basically the same.
  • the coating thickness of the second active material layer 412 is 90%-100% of the coating thickness of the first active material layer 411
  • the coating thickness of the third active material layer 413 is The coating thickness is 80%-110% of the coating thickness of the first active material layer 411
  • the compacted density of the second active material layer 412 is smaller than either of the first active material layer 411 and the third active material layer 413. Compacted density.
  • the coating direction refers to the direction perpendicular to the plane where the first coating area 41 is located, the active material
  • the coating thickness of the layer is the size of the active material layer in a direction perpendicular to the plane of the first coating area 41 .
  • the compacted density refers to the density of the active material layer 411 after compaction and molding.
  • the first active material layer 411, the second active material layer 412 and the third active material layer 413 are arranged according to the above height.
  • the size ratio, the coating thickness ratio and the coating weight ratio are set, wherein the coating weight of the second active material layer 412 is significantly smaller than the coating weights of the first active material layer 411 and the third active material layer 413, and the second active material layer 412
  • the coating thickness of the material layer 412 is within a small deviation from the coating thickness of the first active material layer 411 and the third active material layer 413, resulting in a compacted density of the second active material layer 412 that is smaller than the first active material.
  • the compaction density of any one of the layer 411 and the third active material layer 413 is conducive to the preservation of the electrolyte, so that the material expansion of the second active material layer 412 during the discharge process is small, and the absorption of the electrolyte at the top and bottom is reduced. competitive effect.
  • the coating thickness of the first active material layer 411 , the coating thickness of the second active material layer 412 , and the coating thickness of the third active material layer 413 are consistent.
  • the coating thicknesses of the first active material layer 411, the second active material layer 412 and the third active material layer 413 in the first coating area 41 are consistent, that is, the surface of the first coating area 41 has a planar structure. , without protrusions or step-like structures, thereby avoiding structural problems such as powder loss or stress concentration of the battery pole piece 40 during use.
  • the current collector is also provided with a second coating area 42 and a tab area 43.
  • the tab area 43, the second coating area 42 and the first coating area are also provided on the current collector.
  • 41 are arranged on the same surface sequentially from top to bottom along the height direction of the current collector, wherein the second coating area 42 is connected to the first coating area 41, and the second coating area 42 partially overlaps the tab area 43.
  • the second coating area 42 is provided with an insulating material layer
  • the tab area 43 includes a metal conductive plate, which is connected to the current collector or is a part of the current collector.
  • the second coating area 42 of the present application is used to coat insulating materials, and the insulating materials include non-conductive materials such as ceramics and resins.
  • the tab area 43 forms a tab for connecting the current collector and the electrode terminal.
  • the connected arrangement here means that the second coating area 42 is connected to the first coating area 41 without overlapping areas.
  • the first coating area 41 is only coated with the active material layer, and the second coating area 42 is only coated with the active material layer. There is insulation material.
  • the overlapping arrangement means that the second coating area 42 and the tab area 43 are connected and have mutually covering parts, that is, the second The partial structure of the second coating area 42 coated with insulating material is also a partial structure of the tab area 43 .
  • the height dimension of the second coating region 42 is much smaller than the height dimension of the first coating region 41 and can be ignored when calculating the overall height dimension of the current collector.
  • the height dimension of the first coating region 41 The height dimension represents the height dimension of the current collector.
  • the battery pole piece 40 of the present application can be conductively connected to other components through the tab area 43, and a second coating area 42 is provided between the tab area 43 and the first coating area 41, wherein the second coating area 42 is provided There is an insulating material layer, and the second coating area 42 partially overlaps the tab area 3, so that the tab area 43 is isolated from the active material layer through the insulating material layer, and the battery pole piece 40 and the case are assembled into a battery. Finally, the tab area 43 is prevented from being electrically connected to the casing to avoid leakage in the battery assembled by the present application.
  • the height dimension L5 of the overlapping portion of the second coating area 42 and the tab area 43 is 4mm-16mm, and the second coating area 42 does not overlap the tab area 43
  • the height dimension L4 of the part is 0.5-4mm.
  • the overlapping portion of the second coating area 42 and the tab area 43 extends to the outside of the assembled battery casing. Since the overlapping portion of the second coating area 42 and the tab area 43 is coated with an insulating material, Even if this part comes into contact with the case, no conductive connection will occur, thereby preventing battery leakage. At the same time, in order to prevent the active material layer of the first coating area 41 from protruding to the outside of the casing, the height dimension L4 of the second coating area 42 excluding the overlapped portion with the tab area 43 is 0.5-4 mm. The height dimension of the part of the tab area 43 that is not coated with insulating material is L6, and the overall height dimension of the tab area 43 is L5+L6. The specific size depends on the actual situation, and is generally between 6 mm and 40 mm.
  • the conductive connection between the battery pole piece 40 and the case can be effectively prevented, thereby preventing battery leakage.
  • FIG. 6 is a schematic structural diagram of an electrode assembly provided by an embodiment of the present application.
  • the electrode assembly includes a cathode sheet, an anode sheet 50, and an isolation film (not shown in the figure) spaced between the cathode sheet and anode sheet 50.
  • the cathode sheet is the battery pole sheet 40 in any of the above embodiments.
  • the electrode assembly of the present application has the same technical features as the battery pole piece 40 in any of the above embodiments and can achieve the same technical effect, details will not be described again here.
  • At least one surface of the anode sheet 50 is provided with a third coating area 51 opposite to the first coating area 41 , and both ends of the anode sheet 50 are respectively It is provided beyond both ends of the first coating area 41 .
  • the third coating area 51 is coated with the anode active material.
  • the first coating area 41 and the third coating area 51 are arranged opposite to each other and have approximately equal areas.
  • the first coating area 41 and the third coating area are 51 are used together to react with the electrolyte and generate electric current.
  • the coating method of each position along the height direction of the third coating area 51 is consistent, including the same coating material, coating thickness and coating density, and both ends of the height direction of the anode sheet 50 respectively exceed the first coating area.
  • Region 41 is provided at both ends, which may include an insulating layer or anode tab.
  • the first coating area 41 includes a first active material layer 411, a second active material layer 412 and a third active material layer 413 arranged sequentially along the height direction.
  • the first active material layer 411, the second active material layer 412 and The coating method of the third active material layer 413 may be consistent with the coating method of the battery pole piece 40 in any of the above embodiments.
  • the third coating zone 51 and the first coating zone 41 By arranging the third coating zone 51 and the first coating zone 41 to face each other, it can be ensured that all the active materials in the first coating zone 41 and the third coating zone 51 participate in the reaction with the electrolyte, that is, Participate in the discharge process of the electrode assembly, thereby increasing the energy of the battery.
  • the battery usage rate at the middle position corresponding to the second active material layer 412 on the third coating area 51 is 50%-90% of the battery usage rate at the top and bottom of the third coating area 51 , that is, is 50%-90% of the battery usage rate at the positions corresponding to the first active material layer 411 and the third active material layer 413, thereby effectively improving the expansion force of the anode sheet 50 and reducing the expansion and deformation of the anode sheet 50 by 20 %.
  • Figure 7 is a schematic structural diagram of an electrode assembly provided by another embodiment of the present application.
  • the third coating area 51 includes a fourth active material layer 511 and a fifth active material layer 511 connected in sequence from top to bottom along the height direction of the third coating area 51 .
  • the ratio of the coating weight of the fourth active material layer 511, the fifth active material layer 512 and the sixth active material layer 513 to the first active material layer 411, the second active material The ratio of the coating weights of the layer 412 and the third active material layer 413 is consistent, and/or the ratio of the coating thicknesses of the fourth active material layer 511, the fifth active material layer 512 and the sixth active material layer 513 is consistent with that of the third active material layer 412.
  • the ratio of the coating thicknesses of the first active material layer 411 , the second active material layer 412 and the third active material layer 413 is consistent, and/or the height dimension of the fourth active material layer 511 is the height of the first active material layer 411 100%-140% of size, fifth active The height dimension of the material layer 512 is 20%-100% of the height dimension of the second active material layer 412 , and the height dimension of the sixth active material layer 513 is 100%-140% of the height dimension of the third active material layer 413 .
  • the height direction of the third coating area 51 is the height direction of the anode sheet 50
  • the height direction of the anode sheet 50 is the same as the height direction of the battery pole sheet 40 .
  • the fourth active material layer 511 , the fifth active material layer 512 and the sixth active material layer 513 are respectively coated with anode materials, and the coating weight ratio of the anode material is the same as that of the first active material layer 411 , the second active material layer 412 and the
  • the proportion of the coating weight of the third active material layer 413 is consistent with that of the anode material, and/or the proportion of the coating thickness of the anode material is consistent with the coating of the first active material layer 411 , the second active material layer 412 and the third active material layer 413
  • the proportions of thickness are consistent and/or arranged in accordance with the proportions of height and dimensions described above.
  • Arranging the fourth active material layer 511 , the fifth active material layer 512 and the sixth active material layer 513 according to the above-mentioned coating weight, and/or coating thickness, and/or height size ratio can effectively reduce the anode sheet 50
  • the attenuation speed of the central region of the anode sheet 50 is basically the same, thereby ensuring that the attenuation speed of each active material layer along the height direction of the anode sheet 50 is basically the same, thereby cooperating with the cathode sheet 40 to jointly improve the service life of the battery.
  • the coating thickness of the fifth active material layer 512 is 50%-99% of the coating thickness of the fourth active material layer 511 , and/or, the fifth active material layer 512 has a coating thickness of 50%-99%.
  • the coating thickness of the material layer 512 is 50%-99% of the coating thickness of the sixth active material layer 513 .
  • the coating thickness of the fifth active material layer 512 is set smaller than that of the fourth active material layer 511 and smaller than that of the sixth active material layer 513 . Cloth thickness setting.
  • the fourth active material layer 511 , the fifth active material layer 512 and the sixth active material layer 513 are arranged according to the above-mentioned coating thickness ratio to ensure that the attenuation speed of each active material layer along the height direction of the anode sheet 50 is basically the same. In this case, the use of active materials in the fifth active material layer 512 is reduced, thereby reducing the manufacturing cost of the pole piece assembly and avoiding waste of resources.
  • the coating thickness of the fifth active material layer 512 is set to be smaller than the coating thickness of the fourth active material layer 511 and smaller than the coating thickness of the sixth active material layer 513 , the fourth active material layer 511 and the sixth active material layer 513 are A step surface is formed between the fifth active material layer 512 and the sixth active material layer 513 .
  • a third aspect of the present application provides a battery including the electrode assembly of any of the above embodiments.
  • the fourth aspect of the present application provides an electrical device.
  • the electrical device includes the battery of any of the above embodiments, and the battery is used to provide electrical energy.
  • the electrical equipment may be any of the electrical equipment described above.
  • the battery pole piece 40 includes a first coating area 41 , a second coating area 42 and a tab area 43 .
  • the tab area 43, the second coating area 42 and the first coating area 41 are arranged in sequence from top to bottom along the height direction of the current collector, wherein the second coating area 42 is connected to the first coating area 41. , the second coating area 42 and the tab area 43 are partially overlapped.
  • the second coating area 42 is provided with an insulating material layer.
  • the tab area 43 includes a metal conductive plate, and the metal conductive plate is a part of the current collector.
  • the height dimension L5 of the overlapping portion of the second coating area 42 and the tab area 43 is 4mm-16mm.
  • the height dimension L4 of the second coating area 42 excluding the overlapped portion L4 of the tab area 43 is 0.5-4mm.
  • the height dimension L5 of the tab area 43 is 0.5-4mm.
  • the height dimension is L5+L6, and the height dimension is generally 6mm-40mm.
  • the first coating area 41 is provided with an active material layer.
  • the active material layer includes a first active material layer 411, a second active material layer 412 and a third active material layer 413 connected in sequence from top to bottom along the height direction of the current collector.
  • the second active material layer 412 is disposed in the middle position in the height direction of the current collector, and the decay speed of the active material of the second active material layer 412 is smaller than the activity of any one of the first active material layer 411 and the third active material layer 413 . The rate of decay of the material.
  • the second active material layer 412 includes one or more of a lithium iron phosphate layer, a lithium iron manganese phosphate layer, and a lithium titanate layer
  • the first active material layer 411 includes at least one of a nickel cobalt manganese layer and a lithium cobalt oxide layer
  • the third active material layer 413 includes at least one of a nickel cobalt manganese layer and a lithium cobalt oxide layer.
  • the average particle size size of the active material in the second active material layer 412 is smaller than the average particle size size of the active material in any one of the first active material layer 411 and the third active material layer 412 .
  • first boundary line K1 between the first active material layer 411 and the second active material layer 411, the second active material layer 412 and the third active material
  • a second boundary line K2 is provided between the layers 413.
  • the first boundary line K1 and the second boundary line K2 are respectively arranged parallel to the two ends in the height direction of the current collector.
  • the height dimension L1 of the first active material layer 411 is 30% of the height dimension of the first coating area 41
  • the height dimension L2 of the second active material layer 412 is 45% of the height dimension of the first coating area 41
  • the height dimension L2 of the second active material layer 412 is 45% of the height dimension of the first coating area 41 .
  • the height dimension L3 of the active material layer 413 is 25% of the height dimension of the first coating area 41 .
  • the ratio of the coating weight of the first active material layer 411, the coating weight of the second active material layer 412, and the coating weight of the third active material layer 413 is 100%:70%:100%.
  • the coating thickness of the second active material layer 412 is 90%-100% of the coating thickness of the first active material layer 411
  • the coating thickness of the third active material layer 413 is 90%-100% of the coating thickness of the first active material layer 411 .
  • 80%-110%, and the compacted density of the second active material layer 412 is smaller than the compacted density of any one of the first active material layer 411 and the third active material layer 413 .

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Abstract

本申请涉及电池技术领域，特别涉及一种电池极片、极片组件、电池和用电设备。本申请的电池极片包括集流体，集流体的至少一个表面设有第一涂布区，第一涂布区设有活性材料层，活性材料层包括沿集流体的高度方向由上至下依次连接的第一活性材料层、第二活性材料层和第三活性材料层，其中，第二活性材料层的活性材料的衰减速度小于第一活性材料层和第三活性材料层中任一个的活性材料的衰减速度。本申请的电池极片，能够使第一活性材料层、第二活性材料层和第三活性材料层的衰减速度基本一致，进而提高电池极片的整体使用寿命，提高电池的整体使用寿命。

Description

电池极片、极片组件、电池和用电设备
相关申请的交叉引用
本申请要求以下专利申请的优先权和权益，其全部内容通过引用结合在本申请中：
2022年06月30日提交至中国国家知识产权局的、申请号为202210759331.8、名称为“电池极片、极片组件、电池和用电设备”的中国专利申请。
技术领域
本申请涉及电池技术领域，特别涉及一种电池极片、极片组件、电池和用电设备。
背景技术
锂离子电池因能量密度高、平均开路电压高和循环寿命长等优点已广泛应用于移动、便携式电器中。商品化的锂离子电池的极片包含集流体和活性材料层，其中活性材料层为连续均匀的涂层。
吸液能力是影响锂离子电池性能的重要参数，电池的吸液能力主要受极片中部区域的吸液能力限制。由于极片的中部区域承担了大部分的吸液功能，且极片的中部区域的散热能力差，电池使用一段时间后，极片的中部区域的衰减速度高于极片的高度方向的顶部和底部的衰减速度，从而影响电池的整体使用寿命。
发明内容
鉴于现有技术存在的缺陷，本申请的目的在于提供一种电池极片、极片组件、 电池和用电设备，其能够有效地解决极片的中部区域的衰减速度高于极片的高度方向的顶部和底部的衰减速度的问题。
本申请的第一方面公开了一种电池极片，所述电池极片包括：
集流体，所述集流体的至少一个表面设有第一涂布区，所述第一涂布区设有活性材料层，所述活性材料层包括沿所述集流体的高度方向由上至下依次连接的第一活性材料层、第二活性材料层和第三活性材料层，其中，且所述第二活性材料层的活性材料的衰减速度小于所述第一活性材料层和所述第三活性材料层中任一个的活性材料的衰减速度。
本申请的电池极片，通过在集流体的高度方向由上至下设置依次连接的第一活性材料层、第二活性材料层和第三活性材料层，其中，第二活性材料层的活性材料的衰减速度小于第一活性材料层和第三活性材料层中任一个的活性材料的衰减速度，能够降低第二活性材料层的衰减速度，并抵消电池极片的中部区域由于承担了大部分吸液能力而造成的衰减速度，以及散热能力差造成的衰减速度，使第一活性材料层、第二活性材料层和第三活性材料层的衰减速度基本一致，进而提高电池极片的整体使用寿命，提高电池的整体使用寿命。
在本申请的一些实施方式中，所述第二活性材料层包括磷酸铁锂层、磷酸锰铁锂层和钛酸锂层中的一个或几个。其中，磷酸铁锂层、磷酸锰铁锂层和钛酸锂层中任一个的组成材料相较于一般的电极材料衰减速度慢，从而能够降低第二活性材料层的衰减速度，使第一活性材料层、第二活性材料层和第三活性材料层的衰减速度基本一致。
在本申请的一些实施方式中，所述第一活性材料层包括镍钴锰层和钴酸锂层中的至少一个；和/或，所述第三活性材料层包括镍钴锰层和钴酸锂层中的至少一个。其中，镍钴锰层和钴酸锂层中任一个的组成材料均具有较高的能量密度，从而保证电池的能量，同时，镍钴锰层和钴酸锂层中任一个的组成材料的衰减速度均高于磷酸铁锂层、磷酸锰铁锂层和钛酸锂层中任一个的组成材料的衰减速度，从而使第一活性材料层、第二活性材料层和第三活性材料层的衰减速度基本一致。
在本申请的一些实施方式中，所述第二活性材料层的活性材料的粒径尺寸平均值小于所述第一活性材料层和所述第三活性材料层中任一个的活性材料的粒 径尺寸平均值。其中，粒径尺寸平均值小则代表颗粒之间的间隙较小，从而减缓电池极片中电解液的浸润速率，降低电池极片的吸液能力，进而降低第二活性材料层衰减速度。
在本申请的一些实施方式中，所述第二活性材料层的活性材料的粒径尺寸平均值为所述第一活性材料层的活性材料的粒径尺寸平均值的100％～120％；和/或，所述第二活性材料层的活性材料的粒径尺寸平均值为所述第三活性材料层的活性材料的粒径尺寸平均值的100％～120％。将第二活性材料层的活性材料的粒径尺寸平均值大于第一活性材料层的活性材料的粒径尺寸平均值设置，和/或，将第二活性材料层的活性材料的粒径尺寸平均值大于第三活性材料层的活性材料的粒径尺寸平均值设置，且差值范围在20％内，同时结合第二活性材料层的活性材料的衰减速度小于第一活性材料层和第三活性材料层中任一个的活性材料的衰减速度，同样能够保证第一活性材料层、第二活性材料层和第三活性材料层的衰减速度基本一致。
在本申请的一些实施方式中，所述第一活性材料层和所述第二活性材料层间设有第一边界线，所述第二活性材料层和所述第三活性材料层间设有第二边界线，所述第一边界线和所述第二边界线分别与所述集流体高度方向的两端平行设置。通过将第一边界线和第二边界线分别与集流体高度方向的两端平行设置，能够保证沿集流体的同一高度方向具有相同的活性材料层，从而使第一活性材料层、第二活性材料层和第三活性材料层的衰减速度基本一致。
在本申请的一些实施方式中，所述第二活性材料层设于所述集流体的高度方向的中部位置，所述第一活性材料层的高度尺寸为所述第一涂布区的高度尺寸的10％～40％，所述第二活性材料层的高度尺寸为所述第一涂布区的高度尺寸的20％～80％，所述第三活性材料层的高度尺寸为所述第一涂布区的高度尺寸的10％～40％。根据第一涂布区的高度尺寸，将第一活性材料层、第二活性材料层和第三活性材料层的高度尺寸按照上述比例排列，能够保证第一活性材料层、第二活性材料层和第三活性材料层的衰减速度基本一致。
在本申请的一些实施方式中，所述第一活性材料层的高度尺寸为所述第一涂布区的高度尺寸的25％～35％，所述第二活性材料层的高度尺寸为所述第一涂布 区的高度尺寸的40％～50％，所述第三活性材料层的高度尺寸为所述第一涂布区的高度尺寸的20％～30％。上述高度尺寸的排列比例为本申请的最佳排列比例，从而使第一活性材料层、第二活性材料层和第三活性材料层的衰减速度基本一致。
在本申请的一些实施方式中，所述第二活性材料层的涂布重量为所述第一活性材料层的涂布重量的50％-100％，所述第三活性材料层的涂布重量为所述第一活性材料层的涂布重量的80％-120％。根据第一活性材料层、第二活性材料层和第三活性材料层的材料不同，以及根据第一活性材料层、第二活性材料层和第三活性材料层的高度尺寸的排列比例，将第一活性材料层、第二活性材料层和第三活性材料层按照上述三种重量比例排布，能够保证第一活性材料层、第二活性材料层和第三活性材料层的衰减速度基本一致。
在本申请的一些实施方式中，所述第一活性材料层的涂布重量、所述第二活性材料层的涂布重量以及所述第三活性材料层的涂布重量的比例为90％～110％：60％～80％：90％～110％。上述涂布重量的排列比例为最佳排列比例，从而使第一活性材料层、第二活性材料层和第三活性材料层的衰减速度基本一致。
在本申请的一些实施方式中，所述第二活性材料层的涂布厚度为所述第一活性材料层的涂布厚度的90％-100％，所述第三活性材料层的涂布厚度为所述第一活性材料层的涂布厚度的80％-110％，且所述第二活性材料层的压实密度小于所述第一活性材料层和所述第三活性材料层中任一个的压实密度。根据第一活性材料层、第二活性材料层和第三活性材料层的材料不同，将第一活性材料层、第二活性材料层和第三活性材料层按照上述的高度尺寸比例、涂布厚度比例以及涂布重量比例设置，使第二活性材料层的压实密度小于第一活性材料层和第三活性材料层中任一个的压实密度，有利于对电解液保存，使第二活性材料层在放电过程中的材料膨胀幅度小，减少对顶部和底部吸收电解液的竞争作用。
在本申请的一些实施方式中，所述第一活性材料层的涂布厚度、所述第二活性材料层的涂布厚度以及所述第三活性材料层的涂布厚度相一致。通过将第一活性材料层的涂布厚度、第二活性材料层的涂布厚度以及第三活性材料层的涂布厚度设置成相一致，能够避免电池极片在使用过程中出现掉粉或应力集中等结构性问题。
在本申请的一些实施方式中，所述集流体上还设有第二涂布区和极耳区，所述极耳区、所述第二涂布区和所述第一涂布区沿所述集流体的高度方向由上至下依次设置于同一表面，其中，所述第二涂布区与所述第一涂布区连接设置，所述第二涂布区与所述极耳区部分重叠设置，所述第二涂布区设有绝缘材料层，所述极耳区包括金属导电板，所述金属导电板与所述集流体相连或所述金属导电板为所述集流体的一部分。电池极片能够通过极耳区与其它部件导电连接，并在极耳区与第一涂布区间设置第二涂布区，其中，第二涂布区设有绝缘材料层，且第二涂布区与极耳区部分重叠设置，从而通过绝缘材料层将极耳区与活性材料层相隔绝，并在电池极片与壳体组装成电池后防止极耳区与壳体导电连接。
在本申请的一些实施方式中，所述第二涂布区与所述极耳区重叠部分的高度尺寸为4mm-16mm，所述第二涂布区去除与所述极耳区重叠部分的高度尺寸为0.5mm-4mm。通过上述高度尺寸的范围设置，能够有效地防止电池极片与壳体间导电连接，从而防止电池发生漏电现象。
本申请的第二方面提出了一种电极组件，所述电极组件包括阴极片、阳极片以及设于所述阴极片和所述阳极片之间的隔离膜，其中，所述阴极片为上述任一项所述的电池极片。
由于本申请的电极组件具有与上述任一项所述的电池极片相同的技术特征，能够达到相同的技术效果，在此不再进行赘述。
在本申请的一些实施方式中，所述阳极片的至少一个表面设有与所述第一涂布区正对设置的第三涂布区，且所述阳极片的两端分别超出所述第一涂布区的两端设置。通过将第三涂布区与第一涂布区正对设置，能够保证第一涂布区与第三涂布区中的所有活性材料全部参与到与电解液的反应中，即参与到电极的放电过程中，进而提高电池的能量。
在本申请的一些实施方式中，所述第三涂布区包括沿所述第三涂布区的高度方向由上至下依次连接的第四活性材料层、第五活性材料层和第六活性材料层，其中，所述第四活性材料层、所述第五活性材料层和所述第六活性材料层的涂布重量的比例与所述第一活性材料层、所述第二活性材料层和所述第三活性材料层的涂布重量的比例相一致，和/或，所述第四活性材料层、所述第五活性材料层 和所述第六活性材料层的涂布厚度的比例与所述第一活性材料层、所述第二活性材料层和所述第三活性材料层的涂布厚度的比例相一致，和/或，所述第四活性材料层的高度尺寸为所述第一活性材料层的高度尺寸的100％-140％，所述第五活性材料层的高度尺寸为所述第二活性材料层的高度尺寸的20％-100％，所述第六活性材料层的高度尺寸为所述第三活性材料层的高度尺寸的100％-140％。将第四活性材料层、第五活性材料层和第六活性材料层按照上述涂布重量，和/或涂布厚度，和/或高度尺寸比例排布，能够有效地降低阳极片的中部区域的衰减速度，从而保证阳极片沿高度方向的各活性材料层的衰减速度基本一致，从而与阴极片相配合，共同提高电池的使用寿命。
在本申请的一些实施方式中，所述第五活性材料层的涂布厚度为所述第四活性材料层的涂布厚度的50％-99％，和/或，所述第五活性材料层的涂布厚度为所述第六活性材料层的涂布厚度的50％-99％。将第四活性材料层、第五活性材料层和第六活性材料层按照上述涂布厚度比例排布，在能够保证阳极片沿高度方向的各活性材料层的衰减速度基本一致的情况下，减少第五活性材料层中活性材料的使用，进而降低极片组件的制造成本，避免资源浪费。
本申请的第三方面提出了一种电池，所述电池包括上述任一项所述的电极组件。
本申请的第四方面提出了一种用电设备，所述用电设备包括上述所述的电池，所述电池用于提供电能。
由于本申请的电池和用电设备具有与上述任一项所述的电池极片相同的技术特征，能够达到相同的技术效果，在此不再进行赘述。
上述说明仅是本申请技术方案的概述，为了能够更清楚了解本申请的技术手段，而可依照说明书的内容予以实施，并且为了让本申请的上述和其它目的、特征和优点能够更明显易懂，以下特举本申请的具体实施方式。
附图说明
通过阅读下文优选实施方式的详细描述，各种其他的优点和益处对于本领域 普通技术人员将变得清楚明了。附图仅用于示出优选实施方式的目的，而并不认为是对本申请的限制。而且在整个附图中，用相同的参考符号表示相同的部件。在附图中：
图1是本申请一实施方式提供的车辆的结构示意图；
图2是本申请一实施方式提供的电池包的结构示意图；
图3是本申请一实施方式提供的电池模块的结构示意图；
图4是本申请一实施方式提供的电池单体的分解结构示意图；
图5是本申请一实施方式提供的电池极片的结构示意图；
图6是本申请一实施方式提供的电极组件的结构示意图；
图7是本申请另一实施方式提供的电极组件的结构示意图。
具体实施方式中的附图标号如下：
1：车辆；
10：电池、11：控制器、12：马达；
20：电池模块、21：电池单体、211：端盖、212：壳体、213：电极组件、
214：电极端子；
30：箱体、301：第一部分、302：第二部分；
40：电池极片、41：第一涂布区、411：第一活性材料层、412：第二活性材
料层、413：第三活性材料层、42：第二涂布区、43：极耳区；
50：阳极片、51：第三涂布区、511：第四涂布区、512：第五涂布区、513：
第六涂布区。
具体实施方式
下面将结合附图对本申请技术方案的实施方式进行详细的描述。以下实施方式仅用于更加清楚地说明本申请的技术方案，因此只作为示例，而不能以此来限制本申请的保护范围。
需要注意的是，除非另有说明，本申请实施方式使用的技术术语或者科学术语应当为本申请实施方式所属领域技术人员所理解的通常意义。
在本申请实施方式的描述中，技术术语“中心”、“纵向”、“横向”、“长度”、“宽度”、“厚度”、“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”“内”、“外”、“顺时针”、“逆时针”、“轴向”、“径向”、“周向”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请实施方式和简化描述，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实施方式的限制。
此外，技术术语“第一”、“第二”等仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。在本申请实施方式的描述中，“多个”的含义是两个以上，除非另有明确具体的限定。
在本申请实施方式的描述中，除非另有明确的规定和限定，技术术语“安装”、“相连”、“连接”、“固定”等术语应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或成一体；也可以是机械连接，也可以是电连接；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通或两个元件的相互作用关系。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本申请实施方式中的具体含义。
在本申请实施方式的描述中，除非另有明确的规定和限定，第一特征在第二特征“上”或“下”可以是第一和第二特征直接接触，或第一和第二特征通过中间媒介间接接触。而且，第一特征在第二特征“之上”、“上方”和“上面”可是第一特征在第二特征正上方或斜上方，或仅仅表示第一特征水平高度高于第二特征。第一特征在第二特征“之下”、“下方”和“下面”可以是第一特征在第二特征正下方或斜下方，或仅仅表示第一特征水平高度小于第二特征。
目前，从市场形势的发展来看，动力电池的应用越加广泛。动力电池不仅被应用于水力、火力、风力和太阳能电站等储能电源系统，而且还被广泛应用于电动自行车、电动摩托车、电动汽车等电动交通工具，以及军事装备和航空航天等多个领域。锂离子电池因能量密度高、平均开路电压高和循环寿命长等优点已广泛应用于移动、便携式电器中。商品化的锂离子电池的极片包含集流体和活性材 料层，其中活性材料层为连续均匀的涂层。
本发明人注意到，吸液能力是影响锂离子电池性能的重要参数，电池的吸液能力主要受极片中部区域的吸液能力限制。由于极片的中部区域承担了大部分的吸液功能，且极片的中部区域的散热能力差，电池使用一段时间后，极片的中部区域的衰减速度高于极片的高度方向的顶部和底部的衰减速度，从而影响电池的整体使用寿命。
为解决极片的中部区域的衰减速度高于极片的高度方向的顶部和底部的衰减速度，从而导致电池整体使用寿命下降的问题，申请人研究发现，通过沿极片的高度方向设置不同的活性材料，并使极片的中部区域的活性材料的衰减速度小于极片的高度方向的顶部和底部的衰减速度，能够有效地保证极片沿高度方向各位置的衰减速度基本一致，从而提高电池的整体使用寿命。
基于上述考虑，发明人经过深入研究，设计了一种电池极片，通过在电池极片的集流体的高度方向由上至下设置依次连接的第一活性材料层、第二活性材料层和第三活性材料层，其中，第二活性材料层的活性材料的衰减速度小于第一活性材料层和第三活性材料层中任一个的活性材料的衰减速度，从而能够使第一活性材料层、第二活性材料层和第三活性材料层的衰减速度基本一致，进而提高电池极片的整体使用寿命，提高电池的整体使用寿命。
本申请提供了一种电池极片，以及包括这种电池极片的极片组件、电池和使用该电池的用电设备。这种电池极片及极片组件可适用于任何电池，例如电池单体、电池模块和电池包，或者一次电池和二次电池。这种电池适用于各种使用电池的用电设备，例如手机、便携式设备、笔记本电脑、电瓶车、电动玩具、电动工具、电动车辆、船舶和航天器等，例如，航天器包括飞机、火箭、航天飞机和宇宙飞船等；电池用于为上述用电设备提供电能。
应理解，本申请实施方式描述的技术方案不仅仅局限适用于上述所描述的电池和用电设备，还可以适用于所有包括箱体的电池以及使用电池的用电设备，但为描述简洁，下述实施方式均以电动车辆为例进行说明。
请参照图1，图1为本申请一些实施方式提供的车辆1的结构示意图。车辆1可以为燃油汽车、燃气汽车或新能源汽车，新能源汽车可以是纯电动汽车、混 合动力汽车或增程式汽车等。车辆1的内部设置有电池10，电池10可以设置在车辆1的底部或头部或尾部。电池10可以用于车辆1的供电，例如，电池10可以作为车辆1的操作电源。车辆1还可以包括控制器11和马达12，控制器11用来控制电池10为马达12供电，例如，用于车辆1的启动、导航和行驶时的工作用电需求。
在本申请一些实施方式中，电池10不仅可以作为车辆1的操作电源，还可以作为车辆1的驱动电源，代替或部分地代替燃油或天然气为车辆1提供驱动动力。
为了满足不同的使用电力需求，电池10可以包括多个电池单体21，电池单体21是指组成电池模块20或电池包的最小单元。多个电池单体21可经由电极端子而被串联和/或并联在一起以应用于各种应用场合。本申请中所提到的电池包括电池模块20或电池包。其中，多个电池单体21之间可以串联或并联或混联，混联是指串联和并联的混合。电池10也可以称为电池包。本申请的实施方式中多个电池单体21可以直接组成电池包，也可以先组成电池模块20，电池模块20再组成电池包。
图2示出了本申请一实施方式的电池10的结构示意图。图3示出了本申请一实施方式的电池模块20的结构示意图。结合图2和图3所示，电池10可以包括多个电池模块20和箱体30，多个电池模块20容纳于箱体30内部。箱体30用于容纳电池单体21或电池模块20，以避免液体或其它异物影响电池单体21的充电或放电。箱体30可以是单独的长方体或者圆柱体或球体等简单立体结构，也可以是由长方体或者圆柱体或球体等简单立体结构组合而成的复杂立体结构，本申请实施方式对此并不限定。箱体30的材质可以是如铝合金、铁合金等合金材料，也可以是如聚碳酸酯、聚异氰脲酸酯泡沫塑料等高分子材料，或者是如玻璃纤维加环氧树脂的复合材料，本申请实施方式对此也并不限定。
在一些实施方式中，箱体30可以包括第一部分301和第二部分302，第一部分301与第二部分302相互盖合，第一部分301和第二部分302共同限定出用于容纳电池单体21的空间。第二部分302可以为一端开口的空心结构，第一部分301可以为板状结构，第一部分301盖合于第二部分302的开口侧，以使第一 部分301与第二部分302共同限定出容纳电池单体21的空间；第一部分301和第二部分302也可以是均为一侧开口的空心结构，第一部分301的开口侧盖合于第二部分302的开口侧。
电池模块20可以包括多个电池单体21，多个电池单体21可以先串联或并联或混联组成电池模块20，多个电池模块20再串联或并联或混联组成电池10。电池单体21可呈圆柱体、扁平体、长方体或其它形状等，本申请实施方式对此也不限定。电池单体21一般按封装的方式分成三种：柱形电池单体21、方体方形电池单体21和软包电池单体21，本申请实施方式对此也不限定。但为描述简洁，下述实施方式均以方体方形的锂离子的电池单体21为例进行说明。
图4为本申请一些实施方式提供的电池单体21的分解结构示意图。电池单体21是指组成电池10的最小单元。如图4，电池单体21包括有端盖211、壳体212和电极组件213。
端盖211是指盖合于壳体212的开口处以将电池单体21的内部环境隔绝于外部环境的部件。不限地，端盖211的形状可以与壳体212的形状相适应以配合壳体212。可选地，端盖211可以由具有一定硬度和强度的材质(如铝合金)制成，这样，端盖211在受挤压碰撞时就不易发生形变，使电池单体21能够具备更高的结构强度，安全性能也可以有所提高。端盖211上可以设置有如电极端子214等的功能性部件。电极端子214可以用于与电极组件213电连接，以用于输出或输入电池单体21的电能。在一些实施方式中，端盖211上还可以设置有用于在电池单体21的内部压力或温度达到阈值时泄放内部压力的泄压机构。在一些实施方式中，在端盖211的内侧还可以设置有绝缘件，绝缘件可以用于隔离壳体212内的电连接部件与端盖211，以降低短路的风险。示例性的，绝缘件可以是塑料、橡胶等。
壳体212是用于配合端盖211以形成电池单体21的内部环境的组件，其中，形成的内部环境可以用于容纳电极组件213、电解液(在图中未示出)以及其它部件。壳体212和端盖211可以是独立的部件，可以于壳体212上设置开口，通过在开口处使端盖211盖合开口以形成电池单体21的内部环境。不限地，也可以使端盖211和壳体212一体化，具体地，端盖211和壳体212可以在其它部件 入壳前先形成一个共同的连接面，当需要封装壳体212的内部时，再使端盖211盖合壳体212。壳体212可以是多种形状和多种尺寸的，例如长方体形、圆柱体形、六棱柱形等。具体地，壳体212的形状可以根据电极组件213的具体形状和尺寸大小来确定。壳体212的材质可以是多种，比如，铜、铁、铝、不锈钢、铝合金、塑胶等，本申请实施方式对此不作特殊限制。
电极组件213是电池单体21中发生电化学反应的部件。壳体212内可以包含一个或更多个电极组件213。电极组件213主要由正极片和负极片卷绕或层叠放置形成，并且通常在正极片与负极片之间设有隔膜。正极片和负极片具有活性材料的部分构成电极组件213的主体部，正极片和负极片不具有活性物质的部分各自构成极耳(在图中未示出)。正极极耳和负极极耳可以共同位于主体部的一端或是分别位于主体部的两端。在电池的充放电过程中，正极活性材料和负极活性材料与电解液发生反应，极耳连接电极端子214以形成电流回路。
可以理解的是，下述实施方式是在对电池单体21以图3所示竖直放置时的状态为例进行说明，电池单体21在实际应用时可以其它方式放置。
图5是本申请一实施方式提供的电池极片40的结构示意图。如图5所示，本申请的电池极片40包括集流体，集流体的至少一个表面设有第一涂布区41，第一涂布区41设有活性材料层，活性材料层包括沿集流体的高度方向由上至下依次连接的第一活性材料层411、第二活性材料层412和第三活性材料层413，其中，第二活性材料层412的活性材料的衰减速度小于第一活性材料层411和第三活性材料层413中任一个的活性材料的衰减速度。
具体地，本申请的集流体是指汇集电流的结构或零件，其功用主要是将电池活性物质产生的电流汇集起来以便形成较大的电流对外输出，在锂离子电池上主要指的是金属箔，如铜箔、铝箔。
涂布区是指集流体上用于涂布材料的区域，当然，集流体上也包括不需要进行涂布的区域，如集流体上极耳所在的位置。本申请的第一涂布区41用于涂布活性材料。
活性材料层是指涂布在集流体上由活性材料组成的层状结构。
集流体的高度方向即为电池极片40的高度方向，如图5中所示的箭头方向， 也是电池极片40形成如图4所示的电极组件213后的电极组件213的高度方向。在电池极片40卷绕或层叠成电极组件213前，即电池极片40处于平面展开状态时，电池极片40的宽度方向即为电池极片440形成电极组件213后的高度方向。
此处的连接设置表示相邻的两个活性材料层间相连设置，且无重叠区域。
活性材料的衰减速度是指活性材料失去与电解液发生反应能力的速度。
在本申请的一个实施方式中，电池极片40为阴极片，阴极片的集流体为铝箔，铝箔的单侧表面或双侧表面上通过涂布的方式设有第一活性材料层411、第二活性材料层412和第三活性材料层413。
本申请的电池极片40，通过在集流体的高度方向由上至下设置依次连接的第一活性材料层411、第二活性材料层412和第三活性材料层413，其中，第二活性材料层412的活性材料的衰减速度小于第一活性材料层411和第三活性材料层413中任一个的活性材料的衰减速度，从而能够降低第二活性材料层412的衰减速度，并消电池极片40的中部区域由于承担了大部分吸液能力而造成的衰减速度，以及散热能力差造成的衰减速度，使第一活性材料层411、第二活性材料层412和第三活性材料层413的衰减速度基本一致，进而保证电池极片40的整体使用寿命，提高电池的整体使用寿命。
在本申请的一些实施方式中，如图5所示，第二活性材料层412包括磷酸铁锂层、磷酸锰铁锂层和钛酸锂层中的一个或几个。
具体地，磷酸铁锂层的主要活性材料包括磷酸铁锂，磷酸锰铁锂层的主要活性材料包括磷酸锰铁锂，钛酸锂层的主要活性材料包括钛酸锂，将上述磷酸铁锂、磷酸锰铁锂和钛酸锂中的一个或几种活性材料制成浆料并涂布在集流体的高度方向的中部位置，从而形成第二活性材料层412。
其中磷酸铁锂、磷酸锰铁锂和钛酸锂均具有较高的稳定性和使用寿命，且相较于一般的电极材料衰减速度慢，从而能够降低第二活性材料层412的衰减速度，抵消极片的中部区域由于承担了大部分吸液能力而造成的衰减速度，以及散热能力差造成的衰减速度，进而使第一活性材料层411、第二活性材料层412和第三活性材料层413的衰减速度基本一致。
在本申请的一些实施方式中，如图5所示，第一活性材料层411包括镍钴锰层和钴酸锂层中的至少一个；和/或，第三活性材料层413包括镍钴锰层和钴酸锂层中的至少一个。
具体地，镍钴锰层的主要活性材料包括镍钴锰，钴酸锂层的主要活性材料包括钴酸锂，将镍钴锰和钴酸锂中的一种或两种活性材料制成浆料并涂布在第二活性材料层412的上方连接位置，从而形成第一活性材料层411。将镍钴锰和钴酸锂中的一种或两种活性材料制成浆料并涂布在第二活性材料层412的下方连接位置，从而形成第三活性材料层413。
其中，镍钴锰和钴酸锂均具有较高的能量密度，从而保证电池的能量，同时，镍钴锰和钴酸锂的衰减速度均高于磷酸铁锂、磷酸锰铁锂和钛酸锂的衰减速度，结合电池极片40高度方向的顶部和底部相较于中部区域承担了小部分的吸液能力，且散热能力良好，从而相互抵消，使第一活性材料层411、第二活性材料层412和第三活性材料层413的衰减速度基本一致。
在本申请的一些实施方式中，如图5所示，第二活性材料层412的活性材料的粒径尺寸平均值小于第一活性材料层411和第三活性材料层413中任一个的活性材料的粒径尺寸平均值。
具体地，颗粒的大小称为“粒径(grain size)”，又称“粒度”或者“直径”。当被测颗粒的某种物理特性或物理行为与某一直径的同质球体(或组合)最相近时，就把该球体的直径(或组合)作为被测颗粒的等效粒径(或粒度分布)。第二活性材料层412的活性材料的粒径尺寸平均值小于第一活性材料层411的活性材料的粒径尺寸平均值，同时，第二活性材料层412的活性材料的粒径尺寸平均值小于第三活性材料层413的活性材料的粒径尺寸平均值。
其中，粒径尺寸平均值小则代表颗粒之间的间隙较小，从而减缓电池极片40中的电解液的浸润速率，降低电池极片40的吸液能力。而第二活性材料层412的活性材料的粒径尺寸平均值小于第一活性材料层411和第三活性材料层413中任一个的活性材料的粒径尺寸平均值，则能够有效地降低第二活性材料层412的吸液能力，进而降低第二活性材料层412的衰减速度。
在本申请的一些实施方式中，如图5所示，第二活性材料层412的活性材料 的粒径尺寸平均值为第一活性材料层411的活性材料的粒径尺寸平均值的100％～120％，和/或，第二活性材料层412的活性材料的粒径尺寸平均值为第三活性材料层413的活性材料的粒径尺寸平均值的100％～120％。
具体地，第二活性材料层412的活性材料的粒径尺寸平均值为第一活性材料层411的活性材料的粒径尺寸平均值的100％～120％，同时第二活性材料层412的活性材料的粒径尺寸平均值为第三活性材料层413的活性材料的粒径尺寸平均值的100％～120％。或者，第二活性材料层412的活性材料的粒径尺寸平均值为第一活性材料层411的活性材料的粒径尺寸平均值的100％～120％，同时，第二活性材料层412的活性材料的粒径尺寸平均值小于第三活性材料层413的活性材料的粒径尺寸平均值。或者，第二活性材料层412的活性材料的粒径尺寸平均值小于第一活性材料层411的活性材料的粒径尺寸平均值，同时，第二活性材料层412的活性材料的粒径尺寸平均值为第三活性材料层413的活性材料的粒径尺寸平均值的100％～120％。
将第二活性材料层412的活性材料的粒径尺寸平均值大于第一活性材料层411的活性材料的粒径尺寸平均值设置，和/或，将第二活性材料层412的活性材料的粒径尺寸平均值大于第三活性材料层413的活性材料的粒径尺寸平均值设置，且差值范围在20％内，同时结合第二活性材料层412的活性材料的衰减速度小于第一活性材料层411的活性材料的衰减速度以及小于第三活性材料层413的活性材料的衰减速度，同样能够保证第一活性材料层411、第二活性材料层412和第三活性材料层413的衰减速度基本一致。
在本申请的一些实施方式中，如图5所示，第一活性材料层411和第二活性材料层间412设有第一边界线K1，第二活性材料层412和第三活性材料层413间设有第二边界线K2，第一边界线K1和第二边界线K2分别与集流体高度方向的两端平行设置。
具体地，第一边界线为K1，即第一活性材料层411和第二活性材料层412在第一涂布区41的分隔线，第二边界线为K2，即第二活性材料层412和第三活性材料层413在第一涂布区41的分隔线。
由于集流体呈大致矩形结构，第一边界线为K1和第二边界线为K2分别与 集流体高度方向的两端平行设置，从而将第一活性材料层411、第二活性材料层412和第三活性材料层413分隔成联系设置的矩形结构，从而保证沿集流体的同一高度方向具有相同的活性材料层，从而使第一活性材料层411、第二活性材料层412和第三活性材料层413的衰减速度基本一致。
在本申请的一些实施方式中，如图5所示，第二活性材料层412设于集流体的高度方向的中部位置，第一活性材料层411的高度尺寸L1为第一涂布区41的高度尺寸的10％～40％，第二活性材料层412的高度尺寸L2为第一涂布区41的高度尺寸的20％～80％，第三活性材料层413的高度尺寸L3为第一涂布区41的高度尺寸的10％～40％。
具体地，活性材料层的高度尺寸即为活性材料层在第一涂布区41的高度方向上的尺寸，第一涂布区41的高度方向即为集流体的高度方向，如图5中箭头所示方向。其中，第一涂布区的高度尺寸为第一活性材料层411的高度尺寸L1、第二活性材料层412的高度尺寸L2以及第三活性材料层413的高度尺寸L3的总和。
由于第一活性材料层411、第二活性材料层412和第三活性材料层413沿第一涂布区41的高度方向设置，且第二活性材料层412占据了集流体的中部位置，承担了大部分的吸液能力，因此第二活性材料层412占据的高度尺寸比例大。
根据第一涂布区41的高度尺寸，将第一活性材料层411、第二活性材料层412和第三活性材料层413的高度尺寸按照上述比例排列，能够保证第一活性材料层411、第二活性材料层412和第三活性材料层413的衰减速度基本一致。
在本申请的一些实施方式中，如图5所示，第一活性材料层411的高度尺寸L1为第一涂布区41的高度尺寸的25％～35％，第二活性材料层412的高度尺寸L2为第一涂布区41的高度尺寸的40％～50％，第三活性材料层413的高度尺寸L3为第一涂布区的高度尺寸的20％～30％。
具体地，第一活性材料层411的高度尺寸L1为第一涂布区41的高度尺寸的30％，第二活性材料层412的高度尺寸L2为第一涂布区41的高度尺寸的45％，第三活性材料层413的高度尺寸L3为第一涂布区的高度尺寸的25％。
上述高度尺寸的排列比例仅为本申请实施方式中的最佳排列比例之一，从而 使第一活性材料层411、第二活性材料层412和第三活性材料层413的衰减速度基本一致。
在本申请的一些实施方式中，如图5所示，第二活性材料层412的涂布重量为第一活性材料层411的涂布重量的50％-100％，第三活性材料层413的涂布重量为第一活性材料层411的涂布重量的80％-120％。
具体地，涂布重量是指对应活性材料层中的活性材料的重量总和。其中，第二活性材料层412对应的活性材料的重量总和为第一活性材料层411对应的活性材料的重量总和的50％-100％，第三活性材料层413对应的活性材料的重量总和为第一活性材料层411对应的活性材料的重量总和的80％-120％。
根据第一活性材料层411、第二活性材料层412和第三活性材料层413的材料不同，以及根据第一活性材料层411、第二活性材料层412和第三活性材料层413的高度尺寸的排列比例，将第一活性材料层411、第二活性材料层412和第三活性材料层413按照上述三种重量比例排布，能够保证第一活性材料层411、第二活性材料层412和第三活性材料层413的衰减速度基本一致。
在本申请的一些实施方式中，如图5所示，第一活性材料层411的涂布重量、第二活性材料层412的涂布重量以及第三活性材料层413的涂布重量的比例为90％～110％：60％～80％：90％～110％。
具体地，第一活性材料层411的涂布重量、第二活性材料层412的涂布重量以及第三活性材料层413的涂布重量的比例为100％：70％：100％。
上述涂布重量的排列比例为本申请实施方式的最佳排列比例之一，从而使第一活性材料层411、第二活性材料层412和第三活性材料层413的衰减速度基本一致。
在本申请的一些实施方式中，如图5所示，第二活性材料层412的涂布厚度为第一活性材料层411的涂布厚度的90％-100％，第三活性材料层413的涂布厚度为第一活性材料层411的涂布厚度的80％-110％，且第二活性材料层412的压实密度小于第一活性材料层411和第三活性材料层413中任一个的压实密度。
具体地，涂布方向是指在垂直于第一涂布区41所在平面的方向，活性材料 层的涂布厚度即为活性材料层在垂直于第一涂布区41所在平面的方向上的尺寸。压实密度是指活性材料层411压紧成型后的密度。
根据第一活性材料层411、第二活性材料层412和第三活性材料层413的材料不同，将第一活性材料层411、第二活性材料层412和第三活性材料层413按照上述的高度尺寸比例、涂布厚度比例以及涂布重量比例设置，其中，第二活性材料层412的涂布重量明显小于第一活性材料层411和第三活性材料层413的涂布重量，而第二活性材料层412的涂布厚度则与第一活性材料层411和第三活性材料层413的涂布厚度在较小的偏差内，从而导致第二活性材料层412的压实密度小于第一活性材料层411和第三活性材料层413中任一个的压实密度，进而有利于对电解液保存，使第二活性材料层412在放电过程中的材料膨胀幅度小，减少对顶部和底部吸收电解液的竞争作用。
在本申请的一些实施方式中，如图5所示，第一活性材料层411的涂布厚度、第二活性材料层412的涂布厚度以及第三活性材料层413的涂布厚度相一致。
具体地，第一涂布区41的第一活性材料层411、第二活性材料层412和第三活性材料层413的涂布厚度相一致，即第一涂布区41的表面为平面状结构，无凸起或台阶状结构，从而能够避免电池极片40在使用过程中出现掉粉或应力集中等结构性问题。
在本申请的一些实施方式中，如图5所示，集流体上还设有第二涂布区42和极耳区43，极耳区43、第二涂布区42和第一涂布区41沿集流体的高度方向由上至下依次设置于同一表面，其中，第二涂布区42与第一涂布区41连接设置，第二涂布区42与极耳区43部分重叠设置，第二涂布区42设有绝缘材料层，极耳区43包括金属导电板，金属导电板与集流体相连或金属导电板为集流体的一部分。
具体地，本申请的第二涂布区42用于涂布绝缘材料，绝缘材料包括陶瓷、树脂等非导电材料。极耳区43形成极耳，用于连接集流体和电极端子。
此处的连接设置表示第二涂布区42与第一涂布区41相连设置，且无重叠区域，第一涂布区41仅涂布有活性材料层，第二涂布区42仅涂布有绝缘材料。
重叠设置表示第二涂布区42与极耳区43相连且具有相互覆盖的部分，即第 二涂布区42涂布有绝缘材料的部分结构同样为极耳区43的部分结构。
在本申请的一些实施方式中，第二涂布区42的高度尺寸远小于第一涂布区41的高度尺寸，在计算集流体的整体高度尺寸时可忽略不计，第一涂布区41的高度尺寸即代表集流体的高度尺寸。
本申请的电池极片40能够通过极耳区43与其它部件导电连接，并在极耳区43与第一涂布区41间设置第二涂布区42，其中，第二涂布区42设有绝缘材料层，且第二涂布区42与极耳区3部分重叠设置，从而通过绝缘材料层将极耳区43与活性材料层相隔绝，并在电池极片40与壳体组装成电池后防止极耳区43与壳体导电连接，避免由本申请组装成的电池发生漏电现象。
在本申请的一些实施方式中，如图5所示，第二涂布区42与极耳区43重叠部分的高度尺寸L5为4mm-16mm，第二涂布区42去除与极耳区43重叠部分的高度尺寸L4为0.5-4mm。
具体地，第二涂布区42与极耳区43重叠部分伸出至组装后的电池的壳体的外部，由于第二涂布区42与极耳区43重叠部分涂布有绝缘材料，从而即使该部分与壳体相接触也不会发生导电连接，进而防止电池发生漏电现象。同时，为防止第一涂布区41的活性材料层伸出至壳体的外部，第二涂布区42去除与极耳区43重叠部分的高度尺寸L4为0.5-4mm。极耳区43未涂布有绝缘材料的部分的高度尺寸为L6，极耳区43的整体高度尺寸为L5+L6，具体尺寸根据实际情况而定，一般在6mm-40mm之间。
通过上述高度尺寸的范围设置，能够有效地防止电池极片40与壳体间导电连接，从而防止电池发生漏电现象。
图6是本申请一实施方式提供的电极组件的结构示意图。如图6所示，本申请的第二方面提出了一种电极组件，电极组件包括阴极片、阳极片50以及间隔设于阴极片和阳极片50之间的隔离膜(图中未示出)，其中，阴极片为上述任一实施方式中的电池极片40。
由于本申请的电极组件具有与上述任一实施方式中的电池极片40相同的技术特征，能够达到相同的技术效果，在此不再进行赘述。
在本申请的一些实施方式中，如图6所示，阳极片50的至少一个表面设有与第一涂布区正41对设置的第三涂布区51，且阳极片50的两端分别超出第一涂布区41的两端设置。
具体地，第三涂布区51涂布有阳极活性材料，第一涂布区41与第三涂布区51正对设置，且面积大致相等，第一涂布区41与第三涂布区51共同用于与电解液发生反应并生成电流。其中，第三涂布区51沿高度方向各位置的涂布方式相一致，包括涂布材料、涂布厚度和涂布密度相同，且阳极片50的高度方向的两端分别超出第一涂布区41的两端设置，其中可包括绝缘层或阳极极耳。
其中，第一涂布区41包括沿高度方向依次设置的第一活性材料层411、第二活性材料层412和第三活性材料层413，第一活性材料层411、第二活性材料层412和第三活性材料层413的涂布方式可以与上述任一实施方式中电池极片40的涂布方式相一致。
通过将第三涂布区51与第一涂布区41正对设置，能够保证第一涂布区41与第三涂布区51中的所有活性材料全部参与到与电解液的反应中，即参与到电极组件的放电过程中，进而提高电池的能量。
同时，由于第三涂布区51上与第二活性材料层412相对应的中部位置处的电池使用率为第三涂布区51的顶部和底部的电池使用率的50％-90％，即为与第一活性材料层411和第三活性材料层413相对应的位置处电池使用率的50％-90％，从而能够有效地改善阳极片50的膨胀力，减少阳极片50膨胀变形的20％。
图7是本申请另一实施方式提供的电极组件的结构示意图。如图7所示，在本申请的一些实施方式中，第三涂布区51包括沿第三涂布区51的高度方向由上至下依次连接的第四活性材料层511、第五活性材料层512和第六活性材料层513，其中，第四活性材料层511、第五活性材料层512和第六活性材料层513的涂布重量的比例与第一活性材料层411、第二活性材料层412和第三活性材料层413的涂布重量的比例相一致，和/或，第四活性材料层511、第五活性材料层512和第六活性材料层513的涂布厚度的比例与第一活性材料层411、第二活性材料层412和第三活性材料层413的涂布厚度的比例相一致，和/或，第四活性材料层511的高度尺寸为第一活性材料层411的高度尺寸的100％-140％，第五活性 材料层512的高度尺寸为第二活性材料层412的高度尺寸的20％-100％，第六活性材料层513的高度尺寸为第三活性材料层413的高度尺寸的100％-140％。
具体地，第三涂布区51的高度方向即为阳极片50的高度方向，阳极片50的高度方向与电池极片40的高度方向相同。第四活性材料层511、第五活性材料层512和第六活性材料层513分别涂布有阳极材料，且阳极材料的涂布重量比例与第一活性材料层411、第二活性材料层412和第三活性材料层413的涂布重量的比例相一致，和/或，阳极材料的涂布厚度比例与第一活性材料层411、第二活性材料层412和第三活性材料层413的涂布厚度的比例相一致，和/或，按照上述高度尺寸比例排列。
将第四活性材料层511、第五活性材料层512和第六活性材料层513按照上述涂布重量，和/或涂布厚度，和/或高度尺寸比例排布，能够有效地降低阳极片50的中部区域的衰减速度，从而保证阳极片50沿高度方向的各活性材料层的衰减速度基本一致，从而与阴极片40相配合，共同提高电池的使用寿命。
在本申请的一些实施方式中，如图7所示，第五活性材料层512的涂布厚度为第四活性材料层511的涂布厚度的50％-99％，和/或，第五活性材料层512的涂布厚度为第六活性材料层513的涂布厚度的50％-99％。
具体地，由于第五活性材料层512的电池使用率低，将第五活性材料层512的涂布厚度小于第四活性材料层511的涂布厚度设置，以及小于第六活性材料层513的涂布厚度设置。
将第四活性材料层511、第五活性材料层512和第六活性材料层513按照上述涂布厚度比例排布，在能够保证阳极片50沿高度方向的各活性材料层的衰减速度基本一致的情况下，减少第五活性材料层512中活性材料的使用，进而降低极片组件的制造成本，避免资源浪费。
进一步地，由于将第五活性材料层512的涂布厚度小于第四活性材料层511的涂布厚度设置，以及小于第六活性材料层513的涂布厚度设置，第四活性材料层511、第五活性材料层512和第六活性材料层513间形成台阶面。通过在第五活性材料层512与第四活性材料层511以及与第六活性材料层513的连接处分别设置倒角，可有效地防止应力集中，避免造成阳极片50的损坏。
本申请的第三方面提出了一种电池，该电池包括上述任一实施方式的电极组件。
本申请的第四方面提出了一种用电设备，该用电设备包括上述任一实施方式的电池，该电池用于提供电能。
其中，该用电设备可以为前文所述的任一项的用电设备。
由于本申请的电池和用电设备具有与上述任一项所述的电池极片40相同的技术特征，能够达到相同的技术效果，在此不再进行赘述。
上述说明仅是本申请技术方案的概述，为了能够更清楚了解本申请的技术手段，而可依照说明书的内容予以实施，并且为了让本申请的上述和其它目的、特征和优点能够更明显易懂，以下特举本申请的具体实施方式。
在本申请的一个实施方式中，如图5所示，电池极片40包括第一涂布区41、第二涂布区42和极耳区43。其中，极耳区43、第二涂布区42和第一涂布区41沿集流体的高度方向由上至下依次设置，其中，第二涂布区42与第一涂布区41连接设置，第二涂布区42与极耳区43部分重叠设置，第二涂布区42设有绝缘材料层，极耳区43包括金属导电板，金属导电板为集流体的一部分。第二涂布区42与极耳区43重叠部分的高度尺寸L5为4mm-16mm，第二涂布区42去除与极耳区43重叠部分L4的高度尺寸为0.5-4mm，极耳区43的高度尺寸为L5+L6，高度尺寸一般为6mm-40mm。
第一涂布区41设有活性材料层，活性材料层包括沿集流体的高度方向由上至下依次连接的第一活性材料层411、第二活性材料层412和第三活性材料层413，其中，第二活性材料层412设于集流体的高度方向的中部位置，第二活性材料层412的活性材料的衰减速度小于第一活性材料层411和第三活性材料层413中任一个的活性材料的衰减速度。第二活性材料层412包括磷酸铁锂层、磷酸锰铁锂层和钛酸锂层中的一个或几个，第一活性材料层411包括镍钴锰层和钴酸锂层中的至少一个，第三活性材料层413包括镍钴锰层和钴酸锂层中的至少一个。第二活性材料层412的活性材料的粒径尺寸平均值小于第一活性材料层411和第三活性材料层412中任一个的活性材料的粒径尺寸平均值。第一活性材料层411和第二活性材料层411间设有第一边界线K1，第二活性材料层412和第三活性材料 层413间设有第二边界线K2，第一边界线K1和第二边界线K2分别与集流体高度方向的两端平行设置。第一活性材料层411的高度尺寸L1为第一涂布区41的高度尺寸的30％，第二活性材料层412的高度尺寸L2为第一涂布区41的高度尺寸的45％，第三活性材料层413的高度尺寸L3为第一涂布区41的高度尺寸的25％。第一活性材料层411的涂布重量、第二活性材料层412的涂布重量以及第三活性材料层413的涂布重量的比例为100％：70％：100％。第二活性材料层412的涂布厚度为第一活性材料层411的涂布厚度的90％-100％，第三活性材料层413的涂布厚度为第一活性材料层411的涂布厚度的80％-110％，且第二活性材料层412的压实密度小于第一活性材料层411和第三活性材料层413中任一个的压实密度。
最后应说明的是：以上各实施方式仅用以说明本申请的技术方案，而非对其限制；尽管参照前述各实施方式对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施方式所记载的技术方案进行修改，或者对其中部分或者全部技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施方式技术方案的范围，其均应涵盖在本申请的权利要求和说明书的范围当中。尤其是，只要不存在结构冲突，各个实施方式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方式，而是包括落入权利要求的范围内的所有技术方案。

Claims (20)

  1. 一种电池极片，其特征在于，包括：
    集流体，所述集流体的至少一个表面设有第一涂布区，所述第一涂布区设有活性材料层，所述活性材料层包括沿所述集流体的高度方向由上至下依次连接的第一活性材料层、第二活性材料层和第三活性材料层，其中，所述第二活性材料层的活性材料的衰减速度小于所述第一活性材料层和所述第三活性材料层中任一个的活性材料的衰减速度。
  2. 根据权利要求1所述的电池极片，其特征在于，所述第二活性材料层包括磷酸铁锂层、磷酸锰铁锂层和钛酸锂层中的一个或几个。
  3. 根据权利要求2所述的电池极片，其特征在于，所述第一活性材料层包括镍钴锰层和钴酸锂层中的至少一个；和/或，所述第三活性材料层包括镍钴锰层和钴酸锂层中的至少一个。
  4. 根据权利要求1至3中任一项所述的电池极片，其特征在于，所述第二活性材料层的活性材料的粒径尺寸平均值小于所述第一活性材料层和所述第三活性材料层中任一个的活性材料的粒径尺寸平均值。
  5. 根据权利要求1至3中任一项所述的电池极片，其特征在于，所述第二活性材料层的活性材料的粒径尺寸平均值为所述第一活性材料层的活性材料的粒径尺寸平均值的100％～120％；和/或，所述第二活性材料层的活性材料的粒径尺寸平均值为所述第三活性材料层的活性材料的粒径尺寸平均值的100％～120％。
  6. 根据权利要求1-5中任一项所述的电池极片，其特征在于，所述第一活性材料层和所述第二活性材料层间设有第一边界线，所述第二活性材料层和所述第三活性材料层间设有第二边界线，所述第一边界线和所述第二边界线分别与所述集流体高度方向的两端平行设置。
  7. 根据权利要求6所述的电池极片，其特征在于，所述第二活性材料层设于所述集流体的高度方向的中部位置，所述第一活性材料层的高度尺寸为所述第一涂布区的高度尺寸的10％～40％，所述第二活性材料层的高度尺寸为所述第一涂 布区的高度尺寸的20％～80％，所述第三活性材料层的高度尺寸为所述第一涂布区的高度尺寸的10％～40％。
  8. 根据权利要求7所述的电池极片，其特征在于，所述第一活性材料层的高度尺寸为所述第一涂布区的高度尺寸的25％～35％，所述第二活性材料层的高度尺寸为所述第一涂布区的高度尺寸的40％～50％，所述第三活性材料层的高度尺寸为所述第一涂布区的高度尺寸的20％～30％。
  9. 根据权利要求7所述的电池极片，其特征在于，所述第二活性材料层的涂布重量为所述第一活性材料层的涂布重量的50％-100％，所述第三活性材料层的涂布重量为所述第一活性材料层的涂布重量的80％-120％。
  10. 根据权利要求9所述的电池极片，其特征在于，所述第一活性材料层的涂布重量、所述第二活性材料层的涂布重量以及所述第三活性材料层的涂布重量的比例为90％～110％：60％～80％：90％～110％。
  11. 根据权利要求9所述的电池极片，其特征在于，所述第二活性材料层的涂布厚度为所述第一活性材料层的涂布厚度的90％-100％，所述第三活性材料层的涂布厚度为所述第一活性材料层的涂布厚度的80％-110％，且所述第二活性材料层的压实密度小于所述第一活性材料层和所述第三活性材料层中任一个的压实密度。
  12. 根据权利要求11所述的电池极片，其特征在于，所述第一活性材料层的涂布厚度、所述第二活性材料层的涂布厚度以及所述第三活性材料层的涂布厚度相一致。
  13. 根据权利要求1-12中任一项所述的电池极片，其特征在于，所述集流体上还设有第二涂布区和极耳区，所述极耳区、所述第二涂布区和所述第一涂布区沿所述集流体的高度方向由上至下依次设置于同一表面，其中，所述第二涂布区与所述第一涂布区连接设置，所述第二涂布区与所述极耳区部分重叠设置，所述第二涂布区设有绝缘材料层，所述极耳区包括金属导电板，所述金属导电板与所述集流体相连或所述金属导电板为所述集流体的一部分。
  14. 根据权利要求13所述的电池极片，其特征在于，所述第二涂布区与所述极耳区重叠部分的高度尺寸为4mm-16mm，所述第二涂布区去除与所述极耳区 重叠部分的高度尺寸为0.5mm-4mm。
  15. 一种电极组件，其特征在于，包括阴极片、阳极片以及设于所述阴极片和所述阳极片之间的隔离膜，其中，所述阴极片为根据权利要求1-14中任一项所述的电池极片。
  16. 根据权利要求15所述的电极组件，其特征在于，所述阳极片的至少一个表面设有与所述第一涂布区正对设置的第三涂布区，且所述阳极片的两端分别超出所述第一涂布区的两端设置。
  17. 根据权利要求16所述的电极组件，其特征在于，所述第三涂布区包括沿所述第三涂布区的高度方向由上至下依次连接的第四活性材料层、第五活性材料层和第六活性材料层，其中，所述第四活性材料层、所述第五活性材料层和所述第六活性材料层的涂布重量的比例与所述第一活性材料层、所述第二活性材料层和所述第三活性材料层的涂布重量的比例相一致，和/或，所述第四活性材料层、所述第五活性材料层和所述第六活性材料层的涂布厚度的比例与所述第一活性材料层、所述第二活性材料层和所述第三活性材料层的涂布厚度的比例相一致，和/或，所述第四活性材料层的高度尺寸为所述第一活性材料层的高度尺寸的100％-140％，所述第五活性材料层的高度尺寸为所述第二活性材料层的高度尺寸的20％-100％，所述第六活性材料层的高度尺寸为所述第三活性材料层的高度尺寸的100％-140％。
  18. 根据权利要求17所述的电极组件，其特征在于，所述第五活性材料层的涂布厚度为所述第四活性材料层的涂布厚度的50％-99％，和/或，所述第五活性材料层的涂布厚度为所述第六活性材料层的涂布厚度的50％-99％。
  19. 一种电池，其特征在于，包括根据权利要求15-18中任一项所述的电极组件。
  20. 一种用电设备，其特征在于，包括根据权利要求19所述的电池，所述电池用于提供电能。
PCT/CN2023/082735 2022-06-30 2023-03-21 电池极片、极片组件、电池和用电设备 WO2024001318A1 (zh)

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