WO2023202374A1 - 极片及其制备方法、电极组件、电池单体、电池、用电设备 - Google Patents

极片及其制备方法、电极组件、电池单体、电池、用电设备 Download PDF

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Publication number
WO2023202374A1
WO2023202374A1 PCT/CN2023/086261 CN2023086261W WO2023202374A1 WO 2023202374 A1 WO2023202374 A1 WO 2023202374A1 CN 2023086261 W CN2023086261 W CN 2023086261W WO 2023202374 A1 WO2023202374 A1 WO 2023202374A1
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WO
WIPO (PCT)
Prior art keywords
layer
active material
pole piece
undercoat layer
primer
Prior art date
Application number
PCT/CN2023/086261
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English (en)
French (fr)
Inventor
肖得隽
刘倩
叶永煌
李全国
孙雪阳
喻春鹏
孙婧轩
陈佳华
Original Assignee
宁德时代新能源科技股份有限公司
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Publication of WO2023202374A1 publication Critical patent/WO2023202374A1/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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H01M4/0402—Methods of deposition of the material
    • H01M4/0404—Methods of deposition of the material by coating on electrode collectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H01M4/0402—Methods of deposition of the material
    • H01M4/0409—Methods of deposition of the material by a doctor blade method, slip-casting or roller coating
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • 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, specifically, to a pole piece and its preparation method, electrode assembly, battery cell, battery, and electrical equipment.
  • Electric vehicles have become an important part of the sustainable development of the automobile industry due to their advantages in energy conservation and environmental protection.
  • battery technology is an important factor related to their development.
  • the pole piece is an important part of the battery. In the existing technology, if the quality of the pole piece is poor, it will affect the manufacturing cost and safety of the battery. Therefore, how to improve the quality of pole pieces is an urgent technical problem that needs to be solved in battery technology.
  • This application provides a pole piece and its preparation method, electrode assembly, battery cell, battery, and electrical equipment. This pole piece has better quality.
  • the application provides a pole piece, including: a base material; a base coating coated on the surface of the base material; an active material layer coated on the surface of the base coating, the base coating The coating is located between the base material and the active material layer; wherein, the side of the base coating facing the active material layer is an uneven surface.
  • a primer layer is provided between the base material and the active material layer.
  • the side of the primer layer facing the active material layer is an uneven surface. Based on the three-dimensional structure of the uneven surface, it can increase the distance between the active material layer and the active material layer.
  • the bonding area of the substrate effectively improves the adhesion between the active material layer and the substrate.
  • the primer layer can serve as a buffer layer to reduce the risk of damage to the substrate by the active material layer and improve the fracture ductility of the pole piece.
  • the primer layer includes a first primer layer and a second primer layer.
  • the first primer layer is coated on the surface of the substrate, and the second primer layer is coated on the surface of the substrate. Coat on the side of the first primer layer facing away from the substrate.
  • the first undercoat layer and the second undercoat layer are provided separately to facilitate the coating operation, so that the side of the undercoat layer facing the active material layer forms an uneven surface.
  • the thickness of the first primer layer is uniform and the thickness of the second primer layer is uneven, so as to form an uneven surface. It can increase the bonding area between the thickness direction and the active material layer, thereby increasing the bonding force between the active material layer and the base material.
  • the second primer layer has a hollow portion.
  • the second primer layer has a hollow portion to increase the bonding area with the active material layer in the thickness direction.
  • the second base coating includes a plurality of protrusions protruding from a side of the first base coating away from the substrate, and the plurality of protrusions Start interval setting.
  • the second undercoat layer includes a plurality of protrusions, the structure is dispersed, and has a larger surface area, so that the undercoat layer and the active material layer can have a larger bonding area.
  • the plurality of protrusions are arranged in a rectangular array.
  • each of the protrusions is cylindrical or hemispherical.
  • the protrusions are cylindrical or hemispherical, which facilitates the manufacture of coating molds, facilitates the coating of the second primer layer, and reduces the difficulty of coating.
  • the second primer layer is a grid structure.
  • the second primer layer has a grid structure, which facilitates manufacturing of coating molds and coating operations.
  • the thickness of the first undercoat layer is D1
  • the thickness of the second undercoat layer is D2
  • the median particle diameter of the active material of the active material layer is Dv50, which satisfies 0.1 ⁇ (D1+D2)/Dv50 ⁇ 1.0.
  • the sum of the thickness of the first primer layer and the thickness of the second primer layer is the overall thickness of the primer layer, and the overall thickness of the primer layer and the median particle size of the active material satisfy the above relationship, so as to suit Equipped with different active material layers.
  • the thickness of the pole piece is determined, if the overall thickness of the undercoat is too large, it will be detrimental to the active material capacity of the pole piece and the energy density of the electrode assembly; if the overall thickness of the undercoat is too small, it will be detrimental to the active material. The effect of improving the bonding force between the layer and the base material and the fracture ductility of the pole piece is limited.
  • the median particle size of the active material is controlled to 0.1 ⁇ (D1+D2)/Dv50 ⁇ 1.0 to increase the active material capacity of the pole piece and the energy density of the electrode assembly, while taking into account the adhesion between the active material layer and the substrate. , and the improvement of the fracture ductility strength of the pole piece.
  • the thickness of the first undercoat layer is D1
  • the thickness of the second undercoat layer is D2, satisfying 0.1 ⁇ D1/D2 ⁇ 3.
  • the thickness of the first primer layer and the thickness of the second primer layer satisfy the above relationship to balance the relationship between the improvement of the adhesion force and the loss of the active material capacity.
  • the thickness of the first undercoat layer is D1
  • the thickness of the second undercoat layer is D2
  • the median particle diameter of the active material of the active material layer is Dv50, which satisfies 0.1 Dv50 ⁇ D1 ⁇ 0.3Dv50.
  • the thickness of the first primer layer and the particle size of the active material satisfy the above relationship to balance the relationship between the increase in fracture ductility and the loss of active material capacity.
  • the projected area of the first primer layer on the substrate is S1
  • the projected area of the second primer layer on the substrate is S2, which satisfies 0.2. ⁇ S2/S1 ⁇ 1.
  • the projected area of the second primer layer and the projected area of the first primer layer satisfy the above relationship, which facilitates increasing the adhesive force to the active material layer.
  • the median particle size of the active material of the active material layer is Dv50, satisfying 0.2 ⁇ m ⁇ DV50 ⁇ 20 ⁇ m.
  • the particle size of the active material meets the above range, which can ensure that the pole piece has a larger active material capacity and facilitates the slurry mixing and coating of the pole piece production.
  • the substrate is copper foil or aluminum foil.
  • the base material is copper foil or aluminum foil, which has good conductivity, high toughness and low density.
  • the base coating includes a conductive agent and a binder
  • the conductive agent is at least one of conductive carbon black, conductive carbon tubes, graphene, and Ketjen black
  • the binder The agents are polyacrylic acid, sodium polyacrylate, polyacrylate, styrene-butadiene rubber, sodium carboxymethylcellulose, polyvinylpyrrolidone, polyacrylamide, polyacrylonitrile, polytetrafluoroethylene, polyvinylidene fluoride and their modifications at least one of them.
  • the present application provides an electrode assembly, including: a positive electrode piece; a negative electrode piece; and a separator disposed between the positive electrode piece and the negative electrode piece; wherein, the positive electrode piece and/ Or the negative electrode piece is the electrode piece in the above embodiment.
  • the present application provides a battery cell, including the electrode assembly provided in the above embodiment.
  • the present application provides a battery, including the battery cell provided in the above embodiment.
  • the present application provides an electrical device, including the battery provided in the above embodiment.
  • the present application provides a method for preparing a pole piece, which includes: coating a base coating on the surface of a base material, and the side of the base coating facing away from the base material is an uneven surface; The surface of the layer is coated with an active material layer, so that the undercoat layer is located between the substrate and the active material layer.
  • the prepared pole piece has good adhesion between the active material layer and the base material, and the quality of the pole piece is better.
  • Figure 1 is a schematic structural diagram of a vehicle provided by some embodiments of the present application.
  • Figure 3 is a schematic diagram of the exploded structure of a battery cell provided by some embodiments of the present application.
  • Figure 4 is a schematic structural diagram of a pole piece provided by some embodiments of the present application.
  • Figure 5 is a schematic structural diagram of the base material and primer layer provided by some embodiments of the present application.
  • Figure 6 is a schematic structural diagram of a base material and a primer layer provided by other embodiments of the present application.
  • Figure 7 is a schematic structural diagram of the second primer layer provided by some embodiments of the present application.
  • Figure 9 shows a schematic flow chart of a method for preparing pole pieces according to some embodiments of the present application.
  • an embodiment means that a particular feature, structure or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application.
  • the appearances of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those skilled in the art understand, both explicitly and implicitly, that the embodiments described herein may be combined with other embodiments.
  • multiple refers to more than two (including two).
  • multiple groups refers to two or more groups (including two groups), and “multiple pieces” refers to means two or more pieces (including two pieces), unless otherwise clearly and specifically limited.
  • the battery mentioned refers to a single physical module including one or more battery cells to provide higher voltage and capacity.
  • the battery mentioned in this application may include a battery module or a battery pack.
  • the battery cell includes an electrode assembly and an electrolyte.
  • the electrode assembly consists of a positive electrode sheet, a negative electrode sheet and a separator. Battery cells mainly rely on the movement of metal ions between the positive and negative electrodes to work.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer.
  • the positive electrode active material layer is coated on the surface of the positive electrode current collector.
  • the current collector that is not coated with the positive electrode active material layer protrudes from the coated positive electrode active material.
  • layer of current collector, and the current collector that is not coated with the positive electrode active material layer serves as the positive electrode tab.
  • the material of the positive electrode current collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganate, etc.
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer.
  • the negative electrode active material layer is coated on the surface of the negative electrode current collector.
  • the current collector that is not coated with the negative electrode active material layer protrudes from the current collector that is coated with the negative electrode active material layer.
  • the current collector coated with the negative active material layer serves as the negative electrode tab.
  • the material of the negative electrode current collector can be copper, and the negative electrode active material can be carbon or silicon.
  • the number of positive electrode tabs is multiple and stacked together, and the number of negative electrode tabs is multiple and stacked together.
  • the material of the separator can be PP (polypropylene, polypropylene) or PE (polyethylene, polyethylene), etc.
  • the pole piece includes a base material and an active material layer coated on the surface of the base material.
  • the bonding force between the active material layer and the base material is low.
  • the active material volume of the active material layer expands and contracts during the cycle, it is easy to cause separation of the active material layer and the base material, resulting in detachment of the pole piece. film, thereby increasing the internal resistance and worsening the cycleability; at the same time, the active material layer can easily damage the base material and reduce the fracture ductility of the pole piece.
  • the active material has an irregular shape (such as amorphous carbon, metal oxide, etc.), the active material has more protruding edges and corners.
  • the battery cell composed of the pole piece will have poor safety.
  • corner fractures are prone to occur during the hot pressing and shaping of the electrode assembly.
  • the electrode assembly cannot be used and needs to be scrapped, which leads to an increase in the manufacturing cost of the battery;
  • the pole piece is easy to break during the cycle.
  • the edge of the broken pole piece cannot be embedded with lithium ions, causing lithium precipitation and affecting the capacity of the battery.
  • the broken pole piece can easily pierce the separator, causing the positive electrode to The contact between the negative pole piece and the negative electrode piece caused a short circuit, causing a safety accident.
  • the inventor designed a pole piece after in-depth research, which includes a base material, a base coating and an active material layer.
  • the primer is coated on the surface of the base material
  • the active material layer is coated on the surface of the primer.
  • the primer is located between the substrate and the active material layer.
  • the side of the primer facing the active material layer is a concave and convex surface. It improves the adhesion between the active material layer and the base coating, reduces the risk of damage to the substrate by the active material layer, and improves the fracture ductility of the pole piece, so that the pole piece has better quality.
  • the side of the primer layer facing the active material layer is an uneven surface. Based on the three-dimensional structure of the uneven surface, the bonding area between the active material layer and the substrate can be increased, effectively improving the bonding between the active material layer and the substrate. Adhesion; at the same time, the primer layer can serve as a buffer layer to reduce the risk of damage to the substrate by the active material layer, improve the fracture ductility of the pole piece, and make the pole piece have better quality.
  • the battery cells may include lithium ion secondary batteries, lithium ion primary batteries, lithium-sulfur batteries, sodium lithium ion batteries, sodium ion batteries or magnesium ion batteries, etc., which are not limited in the embodiments of this application.
  • the battery cells disclosed in the embodiments of the present application can be used in, but are not limited to, vehicles, ships, aircraft, and other electrical equipment.
  • the power supply system of the electrical equipment can be composed of the battery cells disclosed in this application.
  • Embodiments of the present application provide an electrical device that uses a battery as a power source.
  • the electrical device can be, but is not limited to, a mobile phone, a tablet computer, a laptop, an electric toy, an electric tool, an electric bicycle, an electric motorcycle, an electric car, a ship, Spacecraft and more.
  • electric toys can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, electric airplane toys, etc.
  • spacecraft can include airplanes, rockets, space shuttles, spaceships, etc.
  • an electrical device is a vehicle.
  • FIG. 1 is a schematic structural diagram of a vehicle 1000 provided by some embodiments of the present application.
  • the vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc.
  • the battery 100 is disposed inside the vehicle 1000 , and the battery 100 may be disposed at the bottom, head, or tail of the vehicle 1000 .
  • the battery 100 can be used to power the vehicle 1000 .
  • the battery 100 can be used as an operating power source for the vehicle 1000 and for the circuit system of the vehicle 1000 , such as for the starting, navigation and operating power requirements of the vehicle 1000 .
  • the vehicle 1000 may also include a controller 200 and a motor 300 .
  • the controller 200 is used to control the battery 100 to provide power to the motor 300 , for example, for starting, navigating and driving the vehicle 1000 .
  • the battery 100 can not only be used as an operating power source for the vehicle 1000 , but also can be used as a driving power source for the vehicle 1000 , replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000 .
  • FIG. 2 is a schematic diagram of an exploded structure of the battery 100 provided by some embodiments of the present application.
  • the battery 100 includes a case 10 and battery cells 20 , and the battery cells 20 are accommodated in the case 10 .
  • the box 10 is used to provide an accommodation space for the battery cells 20, and the box 10 can adopt a variety of structures.
  • the box 10 may include a first part 11 and a second part 12 , the first part 11 and the second part 12 cover each other, and the first part 11 and the second part 12 jointly define a space for accommodating the battery cells 20 of accommodation space.
  • the second part 12 may be a hollow structure with one end open, and the first part 11 may be a plate-like structure.
  • the first part 11 covers the open side of the second part 12 so that the first part 11 and the second part 12 jointly define a receiving space.
  • the first part 11 and the second part 12 may also be hollow structures with one side open, and the open side of the first part 11 is covered with the open side of the second part 12.
  • the battery 100 there may be a plurality of battery cells 20, and the plurality of battery cells 20 may be connected in series, in parallel, or in mixed connection.
  • Mixed connection means that the plurality of battery cells 20 are connected in series and in parallel.
  • the plurality of battery cells 20 can be directly connected in series or in parallel or mixed together, and then the whole composed of the plurality of battery cells 20 can be accommodated in the box 10 ; of course, the battery 100 can also be a plurality of battery cells 20 First, the battery modules are connected in series, parallel, or mixed to form a battery module, and then multiple battery modules are connected in series, parallel, or mixed to form a whole, and are accommodated in the box 10 .
  • the battery 100 may also include other structures.
  • the battery 100 may further include a bus component for realizing electrical connections between multiple battery cells 20 .
  • Each battery cell 20 may be a secondary battery or a primary battery; it may also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but is not limited thereto.
  • FIG. 3 is an exploded structural diagram of a battery cell 20 provided in some embodiments of the present application.
  • the battery cell 20 refers to the smallest unit that constitutes the battery.
  • the battery cell 20 includes an end cover 21 , a case 22 , an electrode assembly 23 and other functional components.
  • the end cap 21 refers to a component that covers the opening of the case 22 to isolate the internal environment of the battery cell 20 from the external environment.
  • the shape of the end cap 21 can be adapted to the shape of the housing 22 to fit the housing 22 .
  • the end cap 21 can be made of a material with a certain hardness and strength (such as aluminum alloy). In this way, the end cap 21 is less likely to deform when subjected to extrusion and collision, so that the battery cell 20 can have higher durability. Structural strength and safety performance can also be improved.
  • Functional components such as electrode terminals 24 may be provided on the end cap 21 . The electrode terminal 24 may be used to electrically connect with the electrode assembly 23 for outputting or inputting electrical energy of the battery cell 20 .
  • the end cap 21 may also be provided with a pressure relief mechanism for releasing the internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold.
  • the end cap 21 can also be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which are not particularly limited in the embodiment of the present application.
  • an insulating member may also be provided inside the end cover 21 , and the insulating member may be used to isolate the electrical connection components in the housing 22 from the end cover 21 to reduce the risk of short circuit.
  • the insulating member may be plastic, rubber, etc.
  • the housing 22 is a component used to cooperate with the end cover 21 to form an internal environment of the battery cell 20 , wherein the formed internal environment can be used to accommodate the electrode assembly 23 , electrolyte, and other components.
  • the housing 22 and the end cover 21 may be independent components, and an opening may be provided on the housing 22.
  • the end cover 21 covers the opening at the opening to form the internal environment of the battery cell 20.
  • the end cover 21 and the housing 22 can also be integrated.
  • the end cover 21 and the housing 22 can form a common connection surface before other components are put into the housing. When it is necessary to encapsulate the inside of the housing 22 At this time, the end cover 21 covers the housing 22 again.
  • the housing 22 can be of various shapes and sizes, such as rectangular parallelepiped, cylinder, hexagonal prism, etc. Specifically, the shape of the housing 22 can be determined according to the specific shape and size of the electrode assembly 23 .
  • the housing 22 may be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which are not particularly limited in the embodiments of the present application.
  • the electrode assembly 23 is a component in the battery cell 20 where electrochemical reactions occur.
  • One or more electrode assemblies 23 may be contained within the housing 22 .
  • the electrode assembly 23 is mainly formed by winding or stacking a positive electrode piece and a negative electrode piece, and is usually provided with a separator between the positive electrode piece and the negative electrode piece.
  • the separator is used to separate the positive electrode piece and the negative electrode piece to prevent the positive electrode from The pole piece and the negative pole piece are internally short-circuited.
  • the portions of the positive electrode tab and the negative electrode tab that contain active material constitute the main body of the electrode assembly 23 , and the portions of the positive electrode tab and the negative electrode tab that do not contain active material each constitute tabs.
  • 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 negative active material react with the electrolyte, and the tabs are connected to the electrode terminals to form a current loop.
  • Figure 4 is a schematic structural diagram of the pole piece 231 provided by some embodiments of the present application.
  • Figure 5 is a schematic structural diagram of the base material 2311 and the undercoat layer 2312 provided by some embodiments of the present application.
  • Figure 6 is A schematic structural diagram of the base material 2311 and the undercoat layer 2312 is provided in other embodiments of the present application.
  • Figure 7 is a schematic structural diagram of the second undercoat layer 23122 provided in some embodiments of the present application.
  • Figure 8 is a schematic structural diagram of the second undercoat layer 23122 provided in some embodiments of the present application.
  • the present application provides a pole piece 231 , which includes a base material 2311 , an undercoat layer 2312 and an active material layer 2313 .
  • the undercoat layer 2312 is coated on the surface of the base material 2311, and the active material layer 2313 is coated on the surface of the undercoat layer 2312.
  • the undercoat layer 2312 is located between the base material 2311 and the active material layer 2313. Among them, the side of the undercoat layer 2312 facing the active material layer 2313 is an uneven surface.
  • the undercoat layer 2312 is coated on the surface of the base material 2311. It may be that the undercoat layer 2312 is coated on the surface of one side of the base material 2311 in the thickness direction Z, or it may be that the undercoat layer 2312 is coated on the base material 2311. surfaces on both sides in the thickness direction. In the figure, the direction indicated by letter Z is the thickness direction of the base material 2311.
  • the active material layer 2313 is coated on the surface of the undercoat layer 2312.
  • the undercoat layer 2312 is located between the base material 2311 and the active material layer 2313. It can be that the base material 2311, the undercoat layer 2312 and the active material layer 2313 are along the base material 2311. arranged in the thickness direction.
  • the side of the undercoat layer 2312 facing the active material layer 2313 is an uneven surface, that is, the side of the undercoat layer 2312 facing away from the base material 2311 is an uneven surface.
  • the base material 2311 may also be called a current collector, which is a component that collects current.
  • the undercoat layer 2312 is a coating used to bond the active material layer 2313 to the base material 2311.
  • the undercoat layer 2312 realizes the electrical connection between the active material layer 2313 and the base material 2311. That is, the undercoat layer 2312 has conductive properties. .
  • the active material layer 2313 is a structure composed of active materials. According to the polarity of the active material, the active material is divided into positive active material and negative active material.
  • the negative active material can be graphite (artificial graphite, natural graphite), amorphous carbon (soft carbon) , hard carbon, other amorphous carbon), and at least one of lithium titanate.
  • the positive active material can be lithium cobalt oxide, lithium manganate, lithium iron phosphate, lithium nickel cobalt manganate, lithium-rich lithium manganate, or nickel cobalt aluminum. At least one kind of lithium acid.
  • a primer layer 2312 is provided between the base material 2311 and the active material layer 2313.
  • the side of the coating 2312 facing the active material layer 2313 is an uneven surface. Based on the three-dimensional structure of the uneven surface, the contact area between the active material layer 2313 and the base material 2311 can be increased, effectively improving the adhesion between the active material layer 2313 and the base material 2311.
  • the primer layer 2312 can serve as a buffer layer to reduce the risk of damage to the substrate 2311 by the active material layer 2313, and improve the fracture ductility of the pole piece 231, so that the pole piece 231 has better quality.
  • the primer layer 2312 can be an integrated structure, or the primer layer 2312 can be a split structure. Different structural forms of the primer layer 2312 can be selected according to different requirements.
  • the undercoat layer 2312 may include a first undercoat layer 23121 and a second undercoat layer 23122.
  • the first undercoat layer 23121 is coated on the substrate 2311.
  • the second undercoat layer 23122 is coated on the side of the first undercoat layer 23121 facing away from the substrate 2311.
  • the first undercoat layer 23121 is located between the base material 2311 and the second undercoat layer 23122.
  • the first undercoat layer 23121 and the second undercoat layer 23122 are provided separately to facilitate the coating operation, so that the side of the undercoat layer 2312 facing the active material layer 2313 forms an uneven surface.
  • the thickness of the first undercoat layer 23121 is uniform, and the thickness of the second undercoat layer 23122 is uneven.
  • the first primer layer 23121 and the second primer layer 23122 are processed separately.
  • the thickness of the first primer layer 23121 is uniform and the thickness of the second primer layer 23122 is uneven, so as to form an uneven surface and increase the thickness of the substrate 2311 direction and the bonding area with the active material layer 2313, thereby increasing the bonding force between the active material layer 2313 and the base material 2311.
  • the second base coating layer 23122 has a hollow portion 23122a.
  • the second undercoat layer 23122 has a hollow portion 23122a.
  • the second undercoat layer 23122 has a larger surface area in the thickness direction of the base material 2311, so as to increase the bonding area with the active material layer 2313.
  • the second undercoat layer 23122 is a grid structure.
  • the grid structure may be: the second primer layer 23122 includes a plurality of first units arranged laterally and a plurality of second units arranged longitudinally, the first units and the second units are arranged at an angle, and the first units and the second units are arranged at an angle.
  • the part in between is the hollow part 23122a.
  • the included angle may be greater than or equal to 60° and less than or equal to 90°. Alternatively, the included angle may be 90°.
  • the transverse direction can be the length direction of the pole piece 231, and the longitudinal direction can be the width direction of the pole piece 231; or, the transverse direction can be the width direction of the pole piece 231, and the longitudinal direction can be the length direction of the pole piece 231; or, The transverse direction may form a certain angle (not 90°) with the length direction of the pole piece 231, and the longitudinal direction may form a certain angle (not 90°) with the width direction of the pole piece 231.
  • a plurality of protrusions 23122b corresponding to the grid structure can be provided on the roller surface of the coating roller.
  • the slurry When the slurry is transferred to the surface of the first undercoat layer 23121, the slurry forms Second base coat 23122.
  • the second primer layer 23122 has a grid structure, which facilitates manufacturing of coating molds and coating operations.
  • the second base coating 23122 includes a plurality of protrusions 23122b, and the plurality of protrusions 23122b protrude from the side of the first base coating 23121 facing away from the substrate 2311 , multiple protrusions 23122b are set at intervals.
  • a plurality of pits corresponding to the protrusions 23122b can be set on the surface of the coating mold (such as the roller surface of the coating roller), and the slurry (constituting the second undercoat layer 23122 material) is applied to the roller surface of the coating roller, and the coating roller transfers the slurry to the surface of the first undercoat layer 23121 to form the second undercoat layer 23122.
  • a plurality of protrusions 23122b are arranged at intervals, and there is a gap between two adjacent protrusions 23122b.
  • the gap is a hollow portion. 23122a, so that the second primer layer 23122 has more surface area.
  • the second undercoat layer 23122 includes a plurality of protrusions 23122b with a dispersed structure and a larger surface area, so that the undercoat layer 2312 and the active material layer 2313 can have a larger bonding area.
  • a plurality of protrusions 23122b are arranged in a rectangular array.
  • the plurality of protrusions 23122b are arranged in a rectangular array.
  • the distance between any two adjacent protrusions 23122b can be the same, or it can also be that the distance between two adjacent protrusions 23122b in each column is equal to the distance between each protrusion 23122b.
  • the distance between two adjacent protrusions 23122b in the row is different.
  • the plurality of protrusions 23122b are in a rectangular array, which facilitates the manufacturing of the coating mold, facilitates the coating of the second primer layer 23122, and reduces the difficulty of coating.
  • each protrusion 23122b is cylindrical or hemispherical.
  • the protrusion 23122b is columnar, and the cross section of the protrusion 23122b can be circular, rectangular, special-shaped, etc.
  • the protrusion 23122b extends along the thickness direction Z of the base material 2311, and the cross section of the protrusion 23122b refers to the surface perpendicular to the extending direction of the protrusion 23122b.
  • the protrusion 23122b is hemispherical, and the protrusion 23122b is arched away from the base material 2311 .
  • the protrusions 23122b are cylindrical or hemispherical, which facilitates the manufacture of coating molds, facilitates the coating of the second primer layer 23122, and reduces the difficulty of coating.
  • the thickness of the first undercoat layer 23121 is D1
  • the thickness of the second undercoat layer 23122 is D2
  • the median particle diameter of the active material of the active material layer 2313 is Dv50, satisfying 0.1 ⁇ (D1 +D2)/Dv50 ⁇ 1.0.
  • the thickness D2 of the second undercoat layer 23122 refers to the size of the second undercoat layer 23122 in the thickness direction Z of the substrate 2311.
  • the thickness D2 of the second undercoat layer 23122 is the height of the column; when the second undercoat layer 23122 is hemispherical, the thickness D2 of the second undercoat layer 23122 is the radius of the hemisphere; when the second undercoat layer 23122 When it is a grid structure, the thickness D2 of the second undercoat layer 23122 is the thickness of the grid structure.
  • the sum of the thickness D1 of the first undercoat layer 23121 and the thickness D2 of the second undercoat layer 23122 is D1 + D2, which can be the overall thickness of the undercoat layer 2312.
  • Dv50 refers to the median particle size of the active material, specifically, the number of particles larger than this particle size value accounts for 50%, and the number of particles smaller than this particle size value also accounts for 50%.
  • the overall thickness of the undercoat layer 2312 and the median particle diameter Dv50 of the active material layer 2313 satisfy the above relationship to adapt to different active material layers 2313.
  • the thickness of the pole piece 231 is determined, if the overall thickness of the undercoat 2312 is too large, it is not conducive to improving the active material capacity of the pole piece 231 and the energy density of the electrode assembly 23; if the overall thickness of the undercoat 2312 is too small, , the effect on improving the bonding force between the active material layer 2313 and the base material 2311 and the fracture tensile strength of the counter electrode piece 231 is limited.
  • the median particle size Dv50 of the active material is controlled to 0.1 ⁇ (D1+D2)/Dv50 ⁇ 1.0 to increase the active material capacity of the pole piece 231 and the energy density of the electrode assembly 23, while taking into account the active material layer 2313 and the substrate. 2311 and the fracture ductility of the pole piece 231.
  • the thickness of the first undercoat layer 23121 is D1
  • the thickness of the second undercoat layer 23122 is D2, satisfying 0.1 ⁇ D1/D2 ⁇ 3.
  • the thickness D1 of the first undercoat layer 23121 and the thickness D2 of the second undercoat layer 23122 satisfy the above requirements. relationship to balance the improvement in adhesion with the loss of capacity of the active material.
  • the overall thickness of the undercoat layer 2312 is the same, when the thickness D1 of the first undercoat layer 23121 is too small, the adhesive force of the undercoat layer 2312 is small, affecting the adhesion between the active material layer 2313 and the base material 2311 Effect; when the thickness D1 of the first primer layer 23121 is too large, the thickness of the second primer layer 23122 is smaller. In the thickness direction of the base material 2311, the adhesion between the active material layer 2313 and the second primer layer 23122 is reduced. The contact area is smaller, so that the active material capacity of the active material layer 2313 is smaller.
  • the thickness D1 of the first primer layer 23121 and the median particle diameter Dv50 of the active material satisfy the above relationship to balance the relationship between the increase in fracture ductility and the loss of active material capacity.
  • the projection of the first primer layer 23121 on the substrate 2311 and the projection of the second primer layer 23122 on the substrate 2311 refer to the projection of the first primer layer 23121 on the substrate 2311 along the thickness direction of the substrate 2311 and the projection of the second primer layer 23122 on the substrate 2311.
  • the projected area of the second undercoat layer 23122 and the projected area of the first undercoat layer 23121 satisfy the above relationship.
  • the projected area of the second undercoat layer 23122 is smaller than the projected area of the first undercoat layer 23121, which can be
  • the projection of the second undercoat layer 23122 is located within the projection of the first undercoat layer 23121, so that the active material layer 2313 and the undercoat layer 2312 have a larger contact area, thereby increasing the adhesion force to the active material layer 2313.
  • the median particle size of the active material meets the above range, which can ensure a larger active material capacity.
  • the substrate 2311 is copper foil or aluminum foil.
  • the base material 2311 is copper foil or aluminum foil, which has good conductivity, high toughness and low density.
  • the base coating 2312 includes a conductive agent and a binder.
  • the conductive agent is at least one of conductive carbon black, conductive carbon tubes, graphene, and Ketjen black.
  • the binder is polyacrylic acid, At least one of sodium polyacrylate, polyacrylate, styrene-butadiene rubber, sodium carboxymethylcellulose, polyvinylpyrrolidone, polyacrylamide, polyacrylonitrile, polytetrafluoroethylene, polyvinylidene fluoride and their modifications .
  • the first undercoat layer 23121 and the second undercoat layer 23122 can use the same formula, such as the same material composition and the same proportion, or the same material composition and different proportions, or different material compositions.
  • the present application also provides an electrode assembly 23.
  • the electrode assembly 23 includes a positive electrode piece, a negative electrode piece and a separator.
  • the separator is disposed between the positive electrode piece and the negative electrode piece; wherein, the positive electrode
  • the pole piece and/or the negative pole piece is the pole piece 231 in the above solution.
  • the positive electrode piece is the pole piece 231 in the above embodiment, or the negative electrode piece is the pole piece 231 in the above solution, or both the positive electrode piece and the negative electrode piece are the pole piece 231 in the above solution.
  • the present application also provides a battery 100.
  • the battery 100 includes the battery cell 20 in the above solution.
  • the present application also provides an electrical device.
  • the electrical device includes the battery 100 in the above solution.
  • the battery 100 is used to provide electrical energy for the electrical device.
  • the powered device may be any of the aforementioned devices or systems using the battery 100 .
  • pole piece 231, the electrode assembly 23, the battery cell 20, the battery and the electrical equipment in the embodiment of the present application.
  • the preparation method of the pole piece 231 in the embodiment of the present application will be described below, and the parts not described in detail can be See the previous embodiments.
  • Figure 9 shows a schematic flow chart of a pole piece preparation method 400 according to some embodiments of the present application.
  • the preparation method 400 of the pole piece may include:
  • the active material layer 2313 is coated on the surface of the undercoat layer 2312 so that the undercoat layer 2312 is located between the base material 2311 and the active material layer 2313.
  • the present application provides a pole piece 231 , which includes a base material 2311 , an undercoat layer 2312 and an active material layer 2313 .
  • the undercoat layer 2312 is coated on the surface of the base material 2311, and the active material layer 2313 is coated on the surface of the undercoat layer 2312.
  • the undercoat layer 2312 is located between the base material 2311 and the active material layer 2313, and the undercoat layer 2312 faces the active material.
  • One side of layer 2313 is an uneven surface.
  • the undercoat 2312 includes a first undercoat 23121 and a second undercoat 23122.
  • the first undercoat 23121 is coated on the surface of the substrate 2311, and the second undercoat 23122 is coated on the surface of the first undercoat 23121.
  • the second undercoat layer 23122 includes a plurality of protrusions 23122b.
  • the plurality of protrusions 23122b protrude from the side of the first undercoat layer 23121 facing away from the base material 2311.
  • the plurality of protrusions 23122b are arranged in a rectangular array. , each protrusion 23122b is hemispherical.
  • Preparation of the primer base material 2311 for the negative electrode plate Dissolve 60% conductive carbon black, 35% styrene-butadiene rubber and 5% sodium carboxymethyl cellulose in deionized water, mix, and stir evenly to obtain the first primer 23121 slurry , apply the first undercoat layer 23121 slurry evenly on a copper foil with a thickness of 6 ⁇ m, and bake it at 50°C for 10 minutes to obtain a pre-treatment substrate 2311.
  • conductive carbon black conductive carbon black
  • styrene-butadiene rubber styrene-butadiene rubber
  • carboxymethylcellulose sodium carboxymethylcellulose sodium
  • Example 2-3 The preparation methods of the primer base material 2311 and the pole piece 231 described in Example 2-3 and Comparative Example 1-3 are consistent with Example 1, except for the thickness of the first primer layer 23121 and the second primer layer 23122. different.
  • the preparation methods of the primer base material 2311 and the pole piece 231 described in Examples 4-6 and Comparative Examples 4-5 are consistent with Example 1, except that the first primer layer 23121 and the second primer layer 23122 are The area ratio of the projection on the material 2311 is different.
  • pole piece 231 is shorter than the length of the steel plate, insert a paper tape with the same width as pole piece 231 and a length greater than 80-150mm of the sample length under pole piece 231, and fix it with wrinkle glue;
  • Test procedures and standards refer to GB/T 29847-2013 Test Methods for Copper Foil for Printed Boards, Chapter 7.
  • the thicknesses of the first undercoat layer 23121 and the second undercoat layer 23122 can be obtained by cross-sectional analysis using an ion polishing scanning electron microscope.

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Abstract

本申请实施例提供一种极片及其制备方法、电极组件、电池单体、电池、用电设备，属于电池技术领域。该极片包括：基材；底涂层，涂覆于所述基材的表面；活性物质层，涂覆于所述底涂层的表面，所述底涂层位于所述基材和所述活性物质层之间；其中，所述底涂层面向所述活性物质层的一面为凹凸面。该极片，具有较佳的质量。

Description

极片及其制备方法、电极组件、电池单体、电池、用电设备
相关申请的交叉引用
本申请要求享有于2022年04月18日提交的名称为“极片及其制备方法、电极组件、电池单体、电池、用电设备”的中国专利申请CN202210405894.7的优先权，该申请的全部内容通过引用并入本文中。
技术领域
本申请涉及电池技术领域，具体而言，涉及一种极片及其制备方法、电极组件、电池单体、电池、用电设备。
背景技术
节能减排是汽车产业可持续发展的关键，电动车辆由于其节能环保的优势成为汽车产业可持续发展的重要组成部分。对于电动车辆而言，电池技术又是关乎其发展的一项重要因素。
极片是电池的重要组成部分，现有技术中，如果极片的质量较差，则会影响电池的制造成本及安全性。因此，如何提高极片的质量，是电池技术一个亟需解决的技术问题。
发明内容
本申请提供一种极片及其制备方法、电极组件、电池单体、电池、用电设备。该极片，具有较佳的质量。
本申请是通过下述技术方案实现的：
第一方面，本申请提供了一种极片，包括：基材；底涂层，涂覆于所述基材的表面；活性物质层，涂覆于所述底涂层的表面，所述底涂层位于所述基材和所述活性物质层之间；其中，所述底涂层面向所述活性物质层的一面为凹凸面。
根据本申请实施例的极片，在基材与活性物质层之间设置底涂层，底涂层的面向活性物质层的一面为凹凸面，基于凹凸面的立体结构，能够增加活性物质层与基材的粘接面积，有效提升活性物质层与基材的粘接力，同时，底涂层能够作为缓冲层，降低活性物质层对基材的损伤风险，提高极片的断裂延展强度。
根据本申请的一些实施例，所述底涂层包括第一底涂层和第二底涂层，所述第一底涂层涂覆于所述基材的表面，所述第二底涂层涂覆于所述第一底涂层背离所述基材的一面。
在上述方案中，第一底涂层和第二底涂层分体设置，便于涂覆操作，以使底涂层的面向活性物质层的一面形成凹凸面。
根据本申请的一些实施例，所述第一底涂层的厚度均匀，所述第二底涂层的厚度不均匀。
在上述方案中，第一底涂层的厚度均匀、第二底涂层的厚度不均匀，以便于形成凹凸面， 能够增加厚度方向与活性物质层的粘接面积，进而增大活性物质层与基材的粘结力。
根据本申请的一些实施例，所述第二底涂层具有镂空部。
在上述方案中，第二底涂层具有镂空部，以便于增大厚度方向与活性物质层的粘接面积。
根据本申请的一些实施例，所述第二底涂层包括多个凸起，所述多个凸起凸出于所述第一底涂层背离所述基材的一面，所述多个凸起间隔设置。
在上述方案中，第二底涂层包括多个凸起，结构分散，具有较多的表面积，从而使得底涂层与活性物质层能够具有较多的粘接面积。
根据本申请的一些实施例，所述多个凸起呈矩形阵列排布。
在上述方案中，多个凸起呈矩形阵列，便于制造涂覆模具，便于第二底涂层的涂覆，降低涂覆难度。
根据本申请的一些实施例，每个所述凸起呈柱状或半球形。
在上述方案中，凸起呈柱状或半球形，便于制造涂覆模具，便于第二底涂层的涂覆，降低涂覆难度。
根据本申请的一些实施例，所述第二底涂层为栅格结构。
在上述方案中，第二底涂层为栅格结构，便于制造涂覆模具，便于涂覆作业。
根据本申请的一些实施例，所述第一底涂层的厚度为D1，所述第二底涂层的厚度为D2，所述活性物质层的活性物质的中值粒径为Dv50，满足0.1≤(D1+D2)/Dv50≤1.0。
在上述方案中，第一底涂层的厚度与第二底涂层的厚度之和为底涂层的整体厚度，底涂层的整体厚度与活性物质的中值粒径满足上述关系，以适配不同的活性物质层。在极片厚度确定的情况下，如果底涂层的整体厚度过大，不利于极片的活性物质容量和电极组件的能量密度的提升；如果底涂层的整体厚度过小，则对活性物质层与基材的粘结力、以及对极片的断裂延展强度改善的效果有限。因此，将活性物质的中值粒度控制于0.1≤(D1+D2)/Dv50≤1.0，以提高极片的活性物质容量和电极组件的能量密度，且兼顾活性物质层与基材的粘结力、以及对极片的断裂延展强度的改善。
根据本申请的一些实施例，所述第一底涂层的厚度为D1，所述第二底涂层的厚度为D2，满足0.1≤D1/D2≤3。
在上述方案中，第一底涂层的厚度和第二底涂层的厚度满足上述关系，以平衡对粘结力的提升与活性物质容量损失之间的关系。
根据本申请的一些实施例，所述第一底涂层的厚度为D1，所述第二底涂层的厚度为D2，所述活性物质层的活性物质的中值粒径为Dv50，满足0.1Dv50≤D1≤0.3Dv50。
在上述方案中，第一底涂层的厚度与活性物质的粒径满足上述关系，以平衡对断裂延展强度提升与活性物质容量损失之间的关系。
根据本申请的一些实施例，所述第一底涂层在所述基材上的投影的面积为S1，所述第二底涂层在所述基材上的投影的面积为S2，满足0.2≤S2/S1＜1。
在上述方案中，第二底涂层的投影的面积和第一底涂层的投影的面积满足上述关系，便于增加对活性物质层的粘结力。
根据本申请的一些实施例，所述活性物质层的活性物质的中值粒径为Dv50，满足0.2μm≤DV50≤20μm。
在上述方案中，活性物质的粒径满足上述范围，能够保证极片具有较多的活性物质容量，同时便于极片生产的合浆与涂敷。
根据本申请的一些实施例，所述基材为铜箔或铝箔。
在上述方案中，基材为铜箔或铝箔，导电性好、韧性高、密度低。
根据本申请的一些实施例，所述底涂层包括导电剂和粘结剂，所述导电剂为导电炭黑、导电碳管、石墨烯、科琴黑中的至少一种，所述粘结剂为聚丙烯酸、聚丙烯酸钠、聚丙烯酸酯、丁苯橡胶、羧甲基纤维素钠、聚乙烯吡咯烷酮、聚丙烯酰胺、聚丙烯腈、聚四氟乙烯、聚偏氟乙烯及其改性物中的至少一种。
第二方面，本申请提供了一种电极组件，包括：正极极片；负极极片；隔膜，设置于所述正极极片和所述负极极片之间；其中，所述正极极片和/或所述负极极片为上述实施例中的极片。
第三方面，本申请提供了一种电池单体，包括上述实施例提供的电极组件。
第四方面，本申请提供了一种电池，包括上述实施例提供的电池单体。
第五方面，本申请提供了一种用电设备，包括上述实施例提供的电池。
第六方面，本申请提供了一种极片的制备方法，包括：在基材的表面涂覆底涂层，所述底涂层背离所述基材的一面为凹凸面；在所述底涂层的表面涂覆活性物质层，使所述底涂层位于所述基材和所述活性物质层之间。
根据本申请实施例的极片的制备方法，制备出的极片，活性物质层与基材具有较好的粘结力，极片的质量较佳。
本申请的附加方面和优点将在下面的描述中部分给出，部分将从下面的描述中变得明显，或通过本申请的实践了解到。
附图说明
为了更清楚地说明本申请实施例的技术方案，下面将对实施例中所需要使用的附图作简单地介绍，应当理解，以下附图仅示出了本申请的某些实施例，因此不应被看作是对范围的限定，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他相关的附图。
图1为本申请一些实施例提供的车辆的结构示意图；
图2为本申请一些实施例提供的电池的分解结构示意图；
图3为本申请一些实施例提供的电池单体的分解结构示意图；
图4为本申请一些实施例提供的极片的结构示意图；
图5为本申请一些实施例提供的基材与底涂层的结构示意图；
图6为本申请另一些实施例提供的基材与底涂层的结构示意图；
图7为本申请一些实施例提供的第二底涂层的结构示意图；
图8为本申请另一些实施例提供的第二底涂层的结构示意图；
图9示出了本申请一些实施例的极片的制备方法的示意性流程图；
在附图中，附图并未按照实际的比例绘制。
标记说明：100-电池；10-箱体；11-第一部分；12-第二部分；20-电池单体；21-端盖；22- 壳体；23-电极组件；231-极片；2311-基材；2312-底涂层；23121-第一底涂层；23122-第二底涂层；23122a-镂空部；23122b-凸起；2313-活性物质层；24-电极端子；200-控制器；300-马达；1000-车辆。
具体实施方式
下面将结合附图对本申请技术方案的实施例进行详细的描述。以下实施例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。
除非另有定义，本文所使用的所有的技术和科学术语与属于本申请的技术领域的技术人员通常理解的含义相同；本文中所使用的术语只是为了描述具体的实施例的目的，不是旨在于限制本申请；本申请的说明书和权利要求书及上述附图说明中的术语“包括”和“具有”以及它们的任何变形，意图在于覆盖不排他的包含。
在本申请实施例的描述中，技术术语“第一”“第二”等仅用于区别不同对象，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、特定顺序或主次关系。
在本文中提及“实施例”意味着，结合实施例描述的特定特征、结构或特性可以包含在本申请的至少一个实施例中。在说明书中的各个位置出现该短语并不一定均是指相同的实施例，也不是与其它实施例互斥的独立的或备选的实施例。本领域技术人员显式地和隐式地理解的是，本文所描述的实施例可以与其它实施例相结合。
在本申请实施例的描述中，术语“和/或”仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如A和/或B，可以表示：存在A，同时存在A和B，存在B这三种情况。另外，本文中字符“/”，一般表示前后关联对象是一种“或”的关系。
在本申请实施例的描述中，术语“多个”指的是两个以上(包括两个)，同理，“多组”指的是两组以上(包括两组)，“多片”指的是两片以上(包括两片)，除非另有明确具体的限定。
在本申请实施例的描述中，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例和简化描述，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例的限制。
在本申请实施例的描述中，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例中的具体含义。
在本申请中，所提及的电池是指包括一个或多个电池单体以提供更高的电压和容量的单一的物理模块。例如，本申请中所提及的电池可以包括电池模块或电池包等。
电池单体包括电极组件和电解液，电极组件由正极片、负极片和隔膜组成。电池单体主要依靠金属离子在正极片和负极片之间移动来工作。正极片包括正极集流体和正极活性物质层，正极活性物质层涂覆于正极集流体的表面，未涂覆正极活性物质层的集流体凸出于已涂覆正极活性物质 层的集流体，未涂覆正极活性物质层的集流体作为正极极耳。以锂离子电池为例，正极集流体的材料可以为铝，正极活性物质可以为钴酸锂、磷酸铁锂、三元锂或锰酸锂等。负极片包括负极集流体和负极活性物质层，负极活性物质层涂覆于负极集流体的表面，未涂覆负极活性物质层的集流体凸出于已涂覆负极活性物质层的集流体，未涂覆负极活性物质层的集流体作为负极极耳。负极集流体的材料可以为铜，负极活性物质可以为碳或硅等。为了保证通过大电流而不发生熔断，正极极耳的数量为多个且层叠在一起，负极极耳的数量为多个且层叠在一起。隔膜的材质可以为PP(polypropylene，聚丙烯)或PE(polyethylene，聚乙烯)等。
极片包括基材和涂覆于基材表面的活性物质层。现有技术中，活性物质层与基材的粘结力较低，随着循环过程中活性物质层的活性物质体积的膨胀收缩，极易造成活性物质层与基材的分离，导致极片脱膜，进而带来内阻升高、循环性变差；同时，活性物质层容易损伤基材，降低极片的断裂延展强度。例如，当活性物质具有不规则形貌(如无定型碳、金属氧化物等)时，活性物质具有较多的凸出棱角，由于这些活性物质在辊压过程中不易形变，其与基材的接触较差，粘结力较小，同时，活性物质的棱角会在辊压过程中对基材造成损伤，降低极片的断裂延展强度，不利于后续加工，使得极片的质量较差。当活性物质层与基材的粘结力较小时，随着循环过程中活性物质体积的膨胀收缩，极易造成贴紧基体表层的活性物质层与基材表面的分离，导致极片脱膜，进而带来内阻升高、循环性变差，严重时，引起电池单体爆炸起火，该极片构成的电池单体的安全性较差。当极片的断裂延展强度低时，一方面，在电极组件的热压、整形等过程中容易发生拐角断裂，此时的电极组件便无法使用，需要报废，导致电池的制造成本升高；另一方面，循环过程中极片容易断裂，在锂离子电池中，断裂的极片边缘无法嵌入锂离子，造成析锂，影响电池的容量，同时，断裂的极片容易刺穿隔膜，造成正极极片与负极极片接触短路，引发安全事故。
鉴于此，为了解决极片的质量差导致的制造成本高、安全性较差的问题，发明人经过深入研究，设计了一种极片，该极片包括基材、底涂层和活性物质层，底涂层涂覆于基材的表面，活性物质层涂覆于底涂层的表面，底涂层位于基材和活性物质层之间，底涂层面向活性物质层的一面为凹凸面，提升活性物质层与底涂层的粘结力，同时，降低活性物质层对基材的损伤风险，提高极片的断裂延展强度，使得极片具有较佳的质量。
在这样的极片中，底涂层的面向活性物质层的一面为凹凸面，基于凹凸面的立体结构，能够增加活性物质层与基材的粘接面积，有效提升活性物质层与基材的粘结力；同时，底涂层能够作为缓冲层，降低活性物质层对基材的损伤风险，提高极片的断裂延展强度，使得极片具有较佳的质量。
本申请中，电池单体可以包括锂离子二次电池、锂离子一次电池、锂硫电池、钠锂离子电池、钠离子电池或镁离子电池等，本申请实施例对此并不限定。
本申请实施例公开的电池单体可以但不限用于车辆、船舶或飞行器等用电设备中。可以使用具备本申请公开的电池单体组成该用电设备的电源系统。
本申请实施例提供一种使用电池作为电源的用电设备，用电设备可以为但不限于手机、平板电脑、笔记本电脑、电动玩具、电动工具、电动自行车、电动摩托车、电动汽车、轮船、航天器等等。其中，电动玩具可以包括固定式或移动式的电动玩具，例如，游戏机、电动汽车玩具、电动轮船玩具和电动飞机玩具等等，航天器可以包括飞机、火箭、航天飞机和宇宙飞船等等。
以下实施例为了方便说明，以本申请一实施例的一种用电装置为车辆为例进行说明。
请参照图1，图1为本申请一些实施例提供的车辆1000的结构示意图。车辆1000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1000的内部设置有电池100，电池100可以设置在车辆1000的底部或头部或尾部。电池100可以用于车辆1000的供电，例如，电池100可以作为车辆1000的操作电源，用于车辆1000的电路系统，例如用于车辆1000的启动、导航和运行时的工作用电需求。
车辆1000还可以包括控制器200和马达300，控制器200用来控制电池100为马达300供电，例如，用于车辆1000的启动、导航和行驶时的工作用电需求。
在本申请一些实施例中，电池100不仅可以作为车辆1000的操作电源，还可以作为车辆1000的驱动电源，代替或部分地代替燃油或天然气为车辆1000提供驱动动力。
请参照图2，图2为本申请一些实施例提供的电池100的分解结构示意图。电池100包括箱体10和电池单体20，电池单体20容纳于箱体10内。其中，箱体10用于为电池单体20提供容纳空间，箱体10可以采用多种结构。在一些实施例中，箱体10可以包括第一部分11和第二部分12，第一部分11与第二部分12相互盖合，第一部分11和第二部分12共同限定出用于容纳电池单体20的容纳空间。第二部分12可以为一端开口的空心结构，第一部分11可以为板状结构，第一部分11盖合于第二部分12的开口侧，以使第一部分11与第二部分12共同限定出容纳空间；第一部分11和第二部分12也可以是均为一侧开口的空心结构，第一部分11的开口侧盖合于第二部分12的开口侧。
在电池100中，电池单体20可以是多个，多个电池单体20之间可串联或并联或混联，混联是指多个电池单体20中既有串联又有并联。多个电池单体20之间可直接串联或并联或混联在一起，再将多个电池单体20构成的整体容纳于箱体10内；当然，电池100也可以是多个电池单体20先串联或并联或混联组成电池模块形式，多个电池模块再串联或并联或混联形成一个整体，并容纳于箱体10内。电池100还可以包括其他结构，例如，该电池100还可以包括汇流部件，用于实现多个电池单体20之间的电连接。
其中，每个电池单体20可以为二次电池或一次电池；还可以是锂硫电池、钠离子电池或镁离子电池，但不局限于此。
请参照图3，图3为本申请一些实施例提供的电池单体20的分解结构示意图。电池单体20是指组成电池的最小单元。如图3，电池单体20包括有端盖21、壳体22、电极组件23以及其他的功能性部件。
端盖21是指盖合于壳体22的开口处以将电池单体20的内部环境隔绝于外部环境的部件。不限地，端盖21的形状可以与壳体22的形状相适应以配合壳体22。可选地，端盖21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21在受挤压碰撞时就不易发生形变，使电池单体20能够具备更高的结构强度，安全性能也可以有所提高。端盖21上可以设置有如电极端子24等的功能性部件。电极端子24可以用于与电极组件23电连接，以用于输出或输入电池单体20的电能。在一些实施例中，端盖21上还可以设置有用于在电池单体20的内部压力或温度达到阈值时泄放内部压力的泄压机构。端盖21的材质也可以是多种的，比如，铜、铁、铝、不锈钢、铝合金、塑胶等，本申请实施例对此不作特殊限制。在一些实施例中，在端盖21的内侧还可以设置有绝缘件，绝缘件可以用于隔离壳体22内的电连接部件与端盖21，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22是用于配合端盖21以形成电池单体20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23、电解液以及其他部件。壳体22和端盖21可以是独立的部件，可以于壳体22上设置开口，通过在开口处使端盖21盖合开口以形成电池单体20的内部环境。不限地，也可以使端盖21和壳体22一体化，具体地，端盖21和壳体22可以在其他部件入壳前先形成一个共同的连接面，当需要封装壳体22的内部时，再使端盖21盖合壳体22。壳体22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22的形状可以根据电极组件23的具体形状和尺寸大小来确定。壳体22的材质可以是多种，比如，铜、铁、铝、不锈钢、铝合金、塑胶等，本申请实施例对此不作特殊限制。
电极组件23是电池单体20中发生电化学反应的部件。壳体22内可以包含一个或更多个电极组件23。电极组件23主要由正极极片和负极极片卷绕或层叠放置形成，并且通常在正极极片与负极极片之间设有隔膜，隔膜用于分隔正极极片和负极极片，以避免正极极片和负极极片内接短路。正极极片和负极极片具有活性物质的部分构成电极组件23的主体部，正极极片和负极极片不具有活性物质的部分各自构成极耳。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，正极活性物质和负极活性物质与电解液发生反应，极耳连接电极端子以形成电流回路。
请参见图4至图8，图4为本申请一些实施例提供的极片231的结构示意图，图5为本申请一些实施例提供的基材2311与底涂层2312的结构示意图，图6为本申请另一些实施例提供的基材2311与底涂层2312的结构示意图，图7为本申请一些实施例提供的第二底涂层23122的结构示意图，图8为本申请另一些实施例提供的第二底涂层23122的结构示意图。根据本申请的一些实施例，参照图4至图8，本申请提供了一种极片231，该极片231包括基材2311、底涂层2312和活性物质层2313。底涂层2312涂覆于基材2311的表面，活性物质层2313涂覆于底涂层2312的表面，底涂层2312位于基材2311和活性物质层2313之间。其中，底涂层2312面向活性物质层2313的一面为凹凸面。
底涂层2312涂覆于基材2311的表面，可以为，底涂层2312涂覆于基材2311的厚度方向Z的一侧的表面，也可以为，底涂层2312涂覆于基材2311的厚度方向的两侧的表面。图中，字母Z所指示的方向为基材2311的厚度方向。
活性物质层2313涂覆于底涂层2312的表面，底涂层2312位于基材2311和活性物质层2313之间，可以为，基材2311、底涂层2312及活性物质层2313沿基材2311的厚度方向排布。
底涂层2312面向活性物质层2313的一面为凹凸面，也即，底涂层2312背离基材2311的一面为凹凸面。
基材2311也可以称为集流体，为汇集电流的部件。
底涂层2312为用于将活性物质层2313粘接于基材2311的涂层，底涂层2312实现活性物质层2313与基材2311的电连接，也即，底涂层2312具有导电的性能。
活性物质层2313为活性物质构成的结构，根据活性物质的极性，活性物质分为正极活性物质和负极活性物质，负极活性物质可以为石墨(人造石墨、天然石墨)、无定形碳(软碳、硬碳、其他无定形碳)、钛酸锂中至少一种，正极活性物质材料可以钴酸锂、锰酸锂、磷酸铁锂、镍钴锰酸锂、富锂锰酸锂、镍钴铝酸锂中至少一种。
根据本申请实施例的极片231，在基材2311与活性物质层2313之间设置底涂层2312，底 涂层2312的面向活性物质层2313的一面为凹凸面，基于凹凸面的立体结构，能够增加活性物质层2313与基材2311的接触面积，有效提升活性物质层2313与基材2311的粘结力，同时，底涂层2312能够作为缓冲层，降低活性物质层2313对基材2311的损伤风险，提高极片231的断裂延展强度，使得极片231具有较佳的质量。
根据本申请的一些实施例，底涂层2312可以为一体式结构，底涂层2312也可以为分体式结构，根据不同的需求，选取不同底涂层2312结构形式。
根据本申请的一些实施例，如图5至图8所示，底涂层2312可以包括第一底涂层23121和第二底涂层23122，第一底涂层23121涂覆于基材2311的表面，第二底涂层23122涂覆于第一底涂层23121背离基材2311的一面。
换句话说，沿基材2311的厚度方向，第一底涂层23121位于基材2311和第二底涂层23122之间。
第一底涂层23121和第二底涂层23122分体设置，便于涂覆操作，以使底涂层2312的面向活性物质层2313的一面形成凹凸面。
根据本申请的一些实施例，第一底涂层23121的厚度均匀，第二底涂层23122的厚度不均匀。
第一底涂层23121与第二底涂层23122分别处理，第一底涂层23121的厚度均匀、第二底涂层23122的厚度不均匀，以便于形成凹凸面，能够增加基材2311的厚度方向与活性物质层2313的粘接面积，进而增大活性物质层2313与基材2311的粘结力。
根据本申请的一些实施例，如图5至图8所示，第二底涂层23122具有镂空部23122a。
第二底涂层23122具有镂空部23122a，第二底涂层23122在基材2311的厚度方向上具有较多的表面积，以便于增大与活性物质层2313的粘接面积。
根据本申请的一些实施例，如图5所示，第二底涂层23122为栅格结构。
栅格结构可以为：第二底涂层23122包括横向设置的多个第一单元和纵向设置的多个第二单元，第一单元与第二单元呈夹角设置，第一单元与第二单元之间的部分为镂空部23122a，如夹角可以大于或等于60°、小于或等于90°，可选地，夹角可以为90°。需要指出的是，横向可以为极片231的长度方向，纵向可以为极片231的宽度方向；或者，横向可以为极片231的宽度方向，纵向可以为极片231的长度方向；又或者，横向可以与极片231的长度方向呈一定的夹角(不为90°)，纵向可以与极片231的宽度方向呈一定的夹角(不为90°)。
当涂覆第二底涂层23122时，可以在涂覆辊的辊面设置多个与栅格结构对应的凸起23122b，当浆料转移至第一底涂层23121的表面后，浆料形成第二底涂层23122。
在上述方案中，第二底涂层23122为栅格结构，便于制造涂覆模具，便于涂覆作业。
根据本申请的一些实施例，如图6至图8所示，第二底涂层23122包括多个凸起23122b，多个凸起23122b凸出于第一底涂层23121背离基材2311的一面，多个凸起23122b间隔设置。
在涂覆第二底涂层23122时，可以在涂覆模具的表面(如涂覆辊的辊面)设置多个与凸起23122b对应的凹坑，将浆料(构成第二底涂层23122的物料)涂覆于涂覆辊的辊面，涂覆辊将浆料转移至第一底涂层23121的表面从而形成第二底涂层23122。
多个凸起23122b间隔设置，相邻的两个凸起23122b之间具有间隙，该间隙为镂空部 23122a，使得第二底涂层23122具有较多表面积。
在上述方案中，第二底涂层23122包括多个凸起23122b，结构分散，具有较多的表面积，从而使得底涂层2312与活性物质层2313能够具有较多的粘接面积。
根据本申请的一些实施例，如图6至图8所示，多个凸起23122b呈矩形阵列排布。
多个凸起23122b呈矩形阵列排布，可以为，任意相邻两个凸起23122b之间的距离相同，或者，也可以为，每列中相邻两个凸起23122b之间的距离与每排中相邻两个凸起23122b之间的距离不同。
多个凸起23122b呈矩形阵列，便于制造涂覆模具，便于第二底涂层23122的涂覆，降低涂覆难度。
根据本申请的一些实施例，每个凸起23122b呈柱状或半球形。
如图7所示，凸起23122b呈柱状，凸起23122b的横截面可以为圆形，也可以为矩形或者异形等。凸起23122b沿基材2311的厚度方向Z延伸，凸起23122b的横截面是指垂直于凸起23122b的延伸方向的面。如图8所示，凸起23122b呈半球形，凸起23122b朝向远离基材2311的方向拱起。
凸起23122b呈柱状或半球形，便于制造涂覆模具，便于第二底涂层23122的涂覆，降低涂覆难度。
根据本申请的一些实施例，第一底涂层23121的厚度为D1，第二底涂层23122的厚度为D2，活性物质层2313的活性物质的中值粒径为Dv50，满足0.1≤(D1+D2)/Dv50≤1.0。
如图7和图8所示，第一底涂层23121的厚度D1，是指第一底涂层23121在基材2311的厚度方向Z上的尺寸。
如图7和图8所示，第二底涂层23122的厚度D2，是指第二底涂层23122在基材2311的厚度方向Z上的尺寸，例如，当第二底涂层23122呈柱状时，第二底涂层23122的厚度D2为柱状的高度；当第二底涂层23122呈半球形时，第二底涂层23122的厚度D2为半球形的半径；当第二底涂层23122为栅格结构时，第二底涂层23122的厚度D2为栅格结构的厚度。
第一底涂层23121的厚度D1与第二底涂层23122的厚度D2之和为D1+D2，可以为底涂层2312的整体厚度。
Dv50是指活性物质的中值粒度，具体为，大于此粒度值的颗粒数占50％，小于此粒度值的颗粒数也占50％。
底涂层2312的整体厚度与活性物质层2313的中值粒径Dv50满足上述关系，以适配不同的活性物质层2313。在极片231厚度确定的情况下，如果底涂层2312的整体厚度过大，不利于极片231的活性物质容量和电极组件23的能量密度的提升；如果底涂层2312的整体厚度过小，则对活性物质层2313与基材2311的粘结力、以及对极片231的断裂延展强度改善的效果有限。因此，将活性物质的中值粒度Dv50控制于0.1≤(D1+D2)/Dv50≤1.0，以提高极片231的活性物质容量和电极组件23的能量密度，且兼顾活性物质层2313与基材2311的粘结力、以及对极片231的断裂延展强度的改善。
根据本申请的一些实施例，第一底涂层23121的厚度为D1，第二底涂层23122的厚度为D2，满足0.1≤D1/D2≤3。
在上述方案中，第一底涂层23121的厚度D1和第二底涂层23122的厚度D2满足上述 关系，以平衡对粘结力的提升与活性物质容量损失之间的关系。在底涂层2312的整体厚度相同的情况下，当第一底涂层23121的厚度D1过小时，则底涂层2312的粘结力较小，影响活性物质层2313与基材2311的粘接效果；当第一底涂层23121的厚度D1过大时，则第二底涂层23122的厚度较小，在基材2311的厚度方向上，活性物质层2313与第二底涂层23122的粘接面积较小，从而使得活性物质层2313的活性物质容量较小。
根据本申请的一些实施例，第一底涂层23121的厚度为D1，第二底涂层23122的厚度为D2，活性物质层2313的活性物质的中值粒径为Dv50，满足0.1Dv50≤D1≤0.3Dv50。
在上述方案中，第一底涂层23121的厚度D1与活性物质的中值粒径Dv50满足上述关系，以平衡对断裂延展强度提升与活性物质容量损失之间的关系。
根据本申请的一些实施例，第一底涂层23121在基材2311上的投影的面积为S1，第二底涂层23122在基材2311上的投影的面积为S2，满足0.2≤S2/S1＜1。
第一底涂层23121在基材2311上的投影和第二底涂层23122在基材2311上的投影，是指，沿基材2311的厚度方向，第一底涂层23121在基材2311上的投影和第二底涂层23122在基材2311上的投影。
第二底涂层23122的投影的面积和第一底涂层23121的投影的面积满足上述关系，第二底涂层23122的投影的免洗小于第一底涂层23121的投影的面积，可以为第二底涂层23122的投影位于第一底涂层23121的投影内，使得活性物质层2313与底涂层2312具有较多的接触面积，进而便于增加对活性物质层2313的粘结力。
根据本申请的一些实施例，活性物质层2313的活性物质的中值粒径为Dv50，满足0.2μm≤DV50≤20μm。
活性物质的中值粒径满足上述范围，能够保证具有较多的活性物质容量。
根据本申请的一些实施例，基材2311为铜箔或铝箔。
基材2311为铜箔或铝箔，导电性好、韧性高、密度低。
根据本申请的一些实施例，底涂层2312包括导电剂和粘结剂，导电剂为导电炭黑、导电碳管、石墨烯、科琴黑中的至少一种，粘结剂为聚丙烯酸、聚丙烯酸钠、聚丙烯酸酯、丁苯橡胶、羧甲基纤维素钠、聚乙烯吡咯烷酮、聚丙烯酰胺、聚丙烯腈、聚四氟乙烯、聚偏氟乙烯及其改性物中的至少一种。
第一底涂层23121和第二底涂层23122可以采用相同的配方，如材料组成相同、配比相同，或者，材料组成相同、配比不同，又或者，材料组成不同。
根据本申请的一些实施例，本申请还提供了一种电极组件23，该电极组件23包括正极极片、负极极片及隔膜，隔膜设置于正极极片和负极极片之间；其中，正极极片和/或负极极片为上述方案中的极片231。
例如，正极极片为上述实施例中的极片231，或者，负极极片为上述方案中的极片231，又或者，正极极片和负极极片均为上述方案中的极片231。
根据本申请的一些实施例，本申请还提供了一种电池单体20，该电池单体20包括上述方案中的电极组件23。
根据本申请的一些实施例，本申请还提供了一种电池100，该电池100包括上述方案中的电池单体20。
根据本申请的一些实施例，本申请还提供了一种用电设备，该用电设备包括上述方案中的电池100，电池100用于为用电设备提供电能。
用电设备可以是前述任一应用电池100的设备或系统。
上文描述了本申请实施例的极片231、电极组件23、电池单体20、电池和用电设备，下面将描述本申请实施例的极片231的制备方法，其中未详细描述的部分可参见前述各实施例。
图9示出了本申请一些实施例的极片的制备方法400的示意性流程图。如图9所示，该极片的制备方法400可以包括：
在基材2311的表面涂覆底涂层2312，底涂层2312背离基材2311的一面为凹凸面；
在底涂层2312的表面涂覆活性物质层2313，使底涂层2312位于基材2311和活性物质层2313之间。
根据本申请实施例的极片的制备方法400，制备出的极片231，活性物质层2313与基材2311具有较好的粘结力，极片231的质量较佳。
根据本申请的一些实施例，参见图4至图8，本申请提供了一种极片231，该极片231包括基材2311、底涂层2312和活性物质层2313。底涂层2312涂覆于基材2311的表面，活性物质层2313涂覆于底涂层2312的表面，底涂层2312位于基材2311和活性物质层2313之间，底涂层2312面向活性物质层2313的一面为凹凸面。底涂层2312包括第一底涂层23121和第二底涂层23122，第一底涂层23121涂覆于基材2311的表面，第二底涂层23122涂覆于第一底涂层23121背离基材2311的一面，第二底涂层23122包括多个凸起23122b，多个凸起23122b凸出于第一底涂层23121背离基材2311的一面，多个凸起23122b呈矩形阵列排布，每个凸起23122b呈半球形。
下文以负极极片的制备为例，介绍具体实施例：
负极极片的底涂基材2311的制备：将60％导电炭黑、35％丁苯橡胶与5％羧甲基纤维素钠溶于去离子水混合，搅拌均匀，得到第一底涂层23121浆料，将该第一底涂层23121浆料均匀地涂布在厚度为6μm的铜箔上，在50℃下烘烤10min，得到前处理基材2311。之后将40％导电炭黑、55％丁苯橡胶与5％羧甲基纤维素钠溶于去离子水混合，搅拌均匀，得到第二底涂层23122浆料，使用带有凹坑的涂覆辊，将该第二底涂层23122浆料涂覆于前处理基材2311上，得到底涂基材2311。
实施例1，负极极片的制备，将负极活性物质(硬碳，Dv50＝5μm)、导电炭黑、丁苯橡胶与羧甲基纤维素钠按95:1.5:2.0:1.5的质量比例与去离子水混合，搅拌均匀，得到负极浆料。将负极浆料涂覆在上述底涂基材2311上，得到负极极片。负极极片经过冷压机处理，压密0.95。
实施例2-3与对比例1-3中所述底涂基材2311与极片231的制备方法均与实施例1一致，不同之处在于第一底涂层23121与第二底涂层23122的厚度不同。
实施例4-6与对比例4-5中所述底涂基材2311与极片231的制备方法均与实施例1一致，不同之处在于第一底涂层23121与第二底涂层23122在基材2311上的投影的面积比不同。
实施例7-8中所述底涂基材2311与极片231的制备方法均与实施例1一致，不同之处在于第二底涂层23122的结构同步。
对比例6中所述极片231不做底涂处理，其余处理方式与实施例1一致。
实施例与对比例的各项性能的测试方法如下：
1、粘结力测试方法：
(1)取干燥后的极片231，用刀片截取宽30mm×长度为100-160mm的试样；
(2)将双面胶贴于钢板上，胶带宽度20mm×长度为90-150mm；
(3)将第(1)步截取的极片231试样贴在双面胶上，测试面朝向双面胶；
(4)若极片231长度小于钢板长度，将宽度与极片231等宽，长度大于试样长度80-150mm的纸带插入极片231下方，并且用皱纹胶固定；
(5)打开高铁拉力机电源，待仪器正常运行后，调整限位块到合适位置；
(6)测试流程与标准参考GB/T 2790 1995。
2、断裂延展强度测试方法：
(1)取干燥后的极片231，用刀片截取宽30mm×长度为100mm的试样。
(2)用皱纹胶将硬纸片固定在试样的两端，将试样固定在高铁拉力机测试段；
(3)打开高铁拉力机电源，待仪器正常运行后，调整限位块到合适位置，进行测试；
(4)测试流程与标准参考GB/T 29847-2013印制板用铜箔试验方法，第7章节。
3、底涂层2312厚度表征方法：
第一底涂层23121与第二底涂层23122的厚度可通过离子抛光扫描电子显微镜断面分析得到。
(1)加热离子抛光处理样品台，用石蜡固定样品在离子抛光处理样品台上；
(2)将样品台装进样品座内并锁好后，进行抽真空操作；
(3)待真空度达到后，对氩气进行最优化，后对样品进行离子抛光；
(4)抛光处理完后，将样品的横截面进行扫描电子显微镜断面分析，测量其底涂层2312的厚度与形貌。
测试结果：
表1.不同底涂层2312厚度(D1/D2)案例对比
由实施例1-4与对比例1-3可以看出，当D1、D2满足上述方案的公式关系时，极片 231的粘结力和断裂延展强度会有明细的提升。若D1/D2的厚度过小，粘结力和断裂延展强度提升很不明显，D1、D2厚度过大，对粘结力、断裂延展强度的提升有限，但不利于电极组件23成本的降低与整体能量密度的提升。
表2.不同投影面积比例的案例对比
由实施例5-7和对比例4-5可以看出，当S2/S1满足上述方案的关系式时，对粘结力有很好的提升，处在范围之外，对粘结力提升均不明显。极片231的断裂延展强度主要和第一底涂层23121的厚度有关。
表3.第二底涂层23122不同排布的案例对比
由实施例8-10与对比例6的数据可以看出，使用第二底涂层23122的排布结构对粘结力均有良好的提升作用，当不使用排布图案时(对比例5)对材料的粘结力提升有限。
虽然已经参考优选实施例对本申请进行了描述，但在不脱离本申请的范围的情况下，可以对其进行各种改进并且可以用等效物替换其中的部件。尤其是，只要不存在结构冲突，各个实施例中所提到的各项技术特征均可以任意方式组合起来。本申请并不局限于文中公开的特定实施例，而是包括落入权利要求的范围内的所有技术方案。

Claims (20)

  1. 一种极片，包括：
    基材；
    底涂层，涂覆于所述基材的表面；
    活性物质层，涂覆于所述底涂层的表面，所述底涂层位于所述基材和所述活性物质层之间；
    其中，所述底涂层面向所述活性物质层的一面为凹凸面。
  2. 根据权利要求1所述的极片，其中，所述底涂层包括第一底涂层和第二底涂层，所述第一底涂层涂覆于所述基材的表面，所述第二底涂层涂覆于所述第一底涂层背离所述基材的一面。
  3. 根据权利要求2所述的极片，其中，所述第一底涂层的厚度均匀，所述第二底涂层的厚度不均匀。
  4. 根据权利要求2或3所述的极片，其中，所述第二底涂层具有镂空部。
  5. 根据权利要求4所述的极片，其中，所述第二底涂层包括多个凸起，所述多个凸起凸出于所述第一底涂层背离所述基材的一面，所述多个凸起间隔设置。
  6. 根据权利要求5所述的极片，其中，所述多个凸起呈矩形阵列排布。
  7. 根据权利要求5所述的极片，其中，每个所述凸起呈柱状或半球形。
  8. 根据权利要求4所述的极片，其中，所述第二底涂层为栅格结构。
  9. 根据权利要求2所述的极片，其中，所述第一底涂层的厚度为D1，所述第二底涂层的厚度为D2，所述活性物质层的活性物质的中值粒径为Dv50，满足0.1≤(D1+D2)/Dv50≤1.0。
  10. 根据权利要求2所述的极片，其中，所述第一底涂层的厚度为D1，所述第二底涂层的厚度为D2，满足0.1≤D1/D2≤3。
  11. 根据权利要求2所述的极片，其中，所述第一底涂层的厚度为D1，所述活性物质层的活性物质的中值粒径为Dv50，满足0.1Dv50≤D1≤0.3Dv50。
  12. 根据权利要求2-11中任一项所述的极片，其中，所述第一底涂层在所述基材上的投影的面积为S1，所述第二底涂层在所述基材上的投影的面积为S2，满足0.2≤S2/S1＜1。
  13. 根据权利要求1-12中任一项所述的极片，其中，所述活性物质层的活性物质的中值粒径为Dv50，满足0.2μm≤Dv50≤20μm。
  14. 根据权利要求1-13中任一项所述的极片，其中，所述基材为铜箔或铝箔。
  15. 根据权利要求1-14中任一项所述的极片，其中，所述底涂层包括导电剂和粘结剂，所述导电剂为导电炭黑、导电碳管、石墨烯、科琴黑中的至少一种，所述粘结剂为聚丙烯酸、聚丙烯酸钠、聚丙烯酸酯、丁苯橡胶、羧甲基纤维素钠、聚乙烯吡咯烷酮、聚丙烯酰胺、聚丙烯腈、聚四氟乙烯、聚偏氟乙烯及其改性物中的至少一种。
  16. 一种电极组件，包括：
    正极极片；
    负极极片；
    隔膜，设置于所述正极极片和所述负极极片之间；
    其中，所述正极极片和/或所述负极极片为根据权利要求1-15中任一项所述的极片。
  17. 一种电池单体，包括如权利要求16所述的电极组件。
  18. 一种电池，包括如权利要求17所述的电池单体。
  19. 一种用电设备，包括如权利要求18所述的电池。
  20. 一种极片的制备方法，包括：
    在基材的表面涂覆底涂层，所述底涂层背离所述基材的一面为凹凸面；
    在所述底涂层的表面涂覆活性物质层，使所述底涂层位于所述基材和所述活性物质层之间。
PCT/CN2023/086261 2022-04-18 2023-04-04 极片及其制备方法、电极组件、电池单体、电池、用电设备 WO2023202374A1 (zh)

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* Cited by examiner, † Cited by third party
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CN110660957A (zh) * 2018-12-29 2020-01-07 宁德时代新能源科技股份有限公司 一种电极极片和电化学装置
CN111900412A (zh) * 2020-07-13 2020-11-06 北京石墨烯研究院 柔性集流体、锂离子电池极片及其制备方法
CN112234164A (zh) * 2020-11-20 2021-01-15 苏州凌威新能源科技有限公司 锂电池极片及其制备方法
CN114220942A (zh) * 2021-12-10 2022-03-22 Oppo广东移动通信有限公司 电池及其电池极片

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US20180006289A1 (en) * 2016-07-01 2018-01-04 Lg Chem, Ltd. Positive electrode for lithium secondary battery and method for preparing the same
CN110660957A (zh) * 2018-12-29 2020-01-07 宁德时代新能源科技股份有限公司 一种电极极片和电化学装置
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