Battery pole piece, coating method, coating equipment and battery cell

Abstract

This application relates to the field of new energy technology, specifically to a battery electrode, a coating method, a coating device, and a battery cell. The battery electrode comprises a main body, with active material layers disposed on both surfaces of the main body; the battery electrode also comprises an identification layer; the identification layer is disposed on at least one surface, and the shape or position of the coating on the two surfaces is different. By means of the above, the application can facilitate distinguishing the two sides of the asymmetrically coated battery electrode.

Description

Technical Field

[0001] The present application relates to the field of new energy technology, and in particular to a battery pole piece, a coating method, a coating device and a battery cell. Background Art

[0002] Power batteries operate through the charging and discharging of their internal cell components, which consist of spaced-apart electrodes and a separator. Active materials must be coated on both sides of the electrodes to enable the cell components to charge and discharge. The rapid development of new energy sources is placing greater and higher demands on the performance of power batteries. To meet these demands, asymmetric coating of the electrode surfaces within the cell components is becoming increasingly common.

[0003] Since the two sides of the electrode cannot be accurately identified by the naked eye or machine after the coating is asymmetrical, it will cause incorrect identification of the battery electrode. Summary of the Invention

[0004] In view of the above problems, the present application provides a battery pole piece, a coating method, a coating device and a battery cell, so as to facilitate the distinction between the two asymmetrically coated sides of the battery pole piece.

[0005] According to one aspect of the present application, a battery electrode is provided, which includes a electrode body, and active material layers are respectively provided on the two surfaces of the electrode body; the battery electrode also includes an identification layer; the identification layer is provided on at least one surface, and the shape or position of the coating on the two surfaces is different.

[0006] By setting an identification layer on at least one surface of the electrode body and making the shapes or positions of the coatings on the two surfaces different, the two surfaces of the electrode body can be accurately identified and distinguished by the naked eye or a machine, ensuring that the battery electrode can be accurately positioned and assembled in the subsequent production.

[0007] In an optional manner, the identification layer is provided on only one surface. By providing the active material layer and the identification layer on one surface of the electrode body and only providing the active material layer on the other surface, the two sides of the battery electrode can be distinguished and identified.

[0008] In an optional manner, identification layers are provided on both surfaces, and the shapes or positions of the identification layers on the two surfaces are different. By setting the shapes or positions of the identification layers on the two surfaces of the electrode body to be different, the two sides of the battery electrode can be distinguished and identified.

[0009] In one alternative embodiment, on a surface provided with a marking layer, the marking layer and the active material layer extend along a first direction and are spaced apart along a second direction, with both the first and second directions located on the surface and perpendicular to each other. Extending the marking layer and the active material layer along the first direction ensures the uniformity of the battery electrode's appearance and facilitates the application of the marking layer and the active material layer. Spaced apart along the second direction, the marking layer and the active material layer are prevented from contacting each other, making it difficult to identify the marking layer and thus distinguishing the two sides of the battery electrode.

[0010] In one optional embodiment, on a surface provided with a marking layer, the marking layer and the active material layer extend along a first direction, and the marking layer includes at least two marking bands spaced apart along a second direction, with both the first and second directions located on the surface and perpendicular to each other. By providing the marking layer with two spaced-apart marking bands, one of which is in contact with the active material layer, rapid identification of both sides of the battery electrode is ensured while also providing insulation between the two sides of the active material layer.

[0011] In an optional embodiment, the identification layer is an insulating layer. By setting the identification layer as an insulating layer, the identification layer coated on the electrode body can not only realize the identification of both sides of the battery electrode, but also play an insulating and protective role for the active material layer on the electrode body.

[0012] In one optional embodiment, the active material layer includes a conductive adhesive layer and an active layer on the surface, in sequence; the identification layer is a conductive adhesive layer. For some battery electrodes, the active material layer on the electrode surface needs to be coated with a conductive adhesive layer before the active layer. To improve the coating efficiency of the battery electrode, the identification layer is also configured as a conductive adhesive layer. The identification layer can be coated at the same time as the conductive adhesive layer in the identification layer, thereby improving the processing efficiency of the battery electrode. In addition, configuring the identification layer as a conductive adhesive layer reduces the number of coating types and thus reduces the preparatory work before coating.

[0013] In one optional embodiment, the electrode body is a single-layer current collector or a composite current collector. Both single-layer current collectors and composite current collectors are used to collect the current generated by the battery active material to form a larger current output. Therefore, the current collector should be in full contact with the active material layer and the internal resistance should be as small as possible.

[0014] According to another aspect of the present application, a battery electrode coating method is provided, wherein the battery electrode includes a electrode body, and the battery electrode coating method includes: coating active material on two surfaces of the electrode body to form an active material layer; coating an identification material on at least one surface to form an identification layer, so that the shapes or positions of the coatings on the two surfaces are different.

[0015] By coating at least one surface of the electrode body with an identification material to form an identification layer, the shape or position of the coating on the two surfaces is made different, thereby enabling the two surfaces of the electrode body to be accurately identified and distinguished by the naked eye or a machine, ensuring that the battery electrode can be accurately positioned and assembled in the subsequent production.

[0016] In an optional manner, the identification material is applied to only one surface to form the identification layer. By coating the active material layer and the identification layer on one surface of the electrode body and coating only the active material layer on the other surface, the two sides of the battery electrode can be distinguished and identified.

[0017] In one alternative, marking materials are applied to both surfaces to form marking layers, with the marking layers having different shapes or positions on the two surfaces. By setting the marking layers on the two surfaces of the electrode body to have different shapes or positions, the two sides of the battery electrode can be distinguished and identified.

[0018] In one optional embodiment, active material is applied to both surfaces of the electrode body to form an active material layer, including: applying the active material along a first direction on both surfaces to form the active material layer; and applying a marking material to at least one surface to form a marking layer, including: applying the marking material along a first direction on at least one surface to form the marking layer, wherein the marking layer and the active material layer are spaced apart along a second direction, with the first and second directions both located on the surface and perpendicular to each other. By applying the marking layer and the active material layer along the first direction, the appearance of the battery electrode is maintained in a uniform manner and the application of the marking layer and the active material layer is facilitated. By spacing the marking layer and the active material layer along the second direction, contact between the marking layer and the active material layer can be avoided, making the marking layer difficult to identify and thus making it difficult to distinguish the two sides of the battery electrode.

[0019] In one optional embodiment, active material is coated on both surfaces of the electrode body to form an active material layer, including: coating the active material along a first direction on both surfaces to form an active material layer; and coating an identification material on at least one surface to form an identification layer, including: coating the identification material along a first direction on at least one surface to form at least two identification bands, the at least two identification bands being spaced apart along a second direction, with both the first and second directions being located on the surface and perpendicular to each other. By providing identification bands at the edges of the active material layers on both sides of the battery electrode, insulation protection is achieved on both sides of the active material layer, providing good working conditions for the active material layer, increasing the service life of the battery electrode, and preventing short circuit failures in the battery electrode. The identification band on one side of the battery electrode is separated from the identification layer to ensure rapid identification of both sides of the battery electrode.

[0020] In one optional embodiment, active materials are coated on both surfaces of the electrode body to form active material layers, including: coating a conductive adhesive layer material and an active layer material on both surfaces in sequence to form the active material layer; and marking materials are coated on at least one surface to form a marking layer, including: coating a conductive adhesive layer material on at least one surface to form the marking layer. For some battery electrodes, the active material layer on the electrode body needs to be coated with a conductive adhesive layer before the active layer. To improve the coating efficiency of the battery electrode, the marking layer is also configured as a conductive adhesive layer. The marking layer can be coated at the same time as the conductive adhesive layer in the marking layer, thereby improving the coating efficiency of the battery electrode. Furthermore, configuring the marking layer as a conductive adhesive layer reduces the number of coating types and, in turn, reduces the preparatory work before coating.

[0021] According to another aspect of the present application, a battery electrode coating device is provided, wherein the battery electrode includes a electrode body, and the battery electrode coating device includes: a back roller for driving the electrode body to move; a coating structure, arranged on one side of the back roller, for coating active material on two surfaces of the electrode body to form an active material layer, and coating an identification material on at least one surface to form an identification layer, and the shapes or positions of the coatings on the two surfaces are different.

[0022] By setting up a back roller, the movement of the battery pole piece can be controlled, and the active material and identification material can be coated on the surface of the pole piece body through the coating structure, and the shape or position of the coating on the two surfaces can be made different, so that the two surfaces of the pole piece body can be accurately identified and distinguished by the naked eye or machine, ensuring that the battery pole piece can be accurately positioned and assembled in the subsequent production.

[0023] In an optional manner, the coating structure includes a first coating head, which is aligned with one side of the back roller and is used to coat the pole piece body on the back roller; a first flow channel and a second flow channel are provided in the first coating head, the first flow channel is used to circulate the active material, and the second flow channel is used to circulate the identification material. The first coating head is aligned with one side of the back roller so that the material extruded from the first coating head can be smoothly coated on the pole piece body. By providing the first flow channel and the second flow channel in the first coating head, the first flow channel is used to circulate the active material, and the second flow channel is used to circulate the identification material, the active material and the identification material are coated simultaneously, thereby effectively ensuring the alignment between the identification material and the active material coated on the pole piece body, thereby improving the qualified rate of the pole piece body production, ensuring the neat appearance of the pole piece body, and facilitating easy identification of both sides of the battery pole piece.

[0024] In one optional embodiment, the coating structure includes a second coating head, which is aligned with one side of the backing roller and is used to coat the pole piece body on the backing roller; a third flow channel and a fourth flow channel are provided in the second coating head, the third flow channel is used to circulate the active material, and the fourth flow channel is used to circulate the identification material; a partition structure is provided at the outlet of the fourth flow channel, which divides the outlet of the fourth flow channel into a first outlet and a second outlet separated from each other, and the edge of the outlet of the third flow channel contacts the edge of the first outlet. By providing the third and fourth flow channels in the second coating head, the third flow channel is used to circulate the active material, and the fourth flow channel is used to circulate the insulating material, the active material and the insulating material are coated simultaneously, ensuring the alignment and effectiveness of the contact between the identification tape on the pole piece body and the active material layer, so that the insulating material can provide reliable and effective insulation protection for the active material. By setting a partition structure at the outlet of the fourth flow channel, the outlet of the fourth flow channel is divided into a first outlet and a second outlet separated from each other, which effectively simplifies the flow channel structure inside the second coating head and reduces the mold opening cost of the second coating head. In addition, by inputting insulating material into the fourth flow channel, the insulating material forms separated identification bands and identification layers on the electrode body through the first outlet and the second outlet respectively, thereby realizing simultaneous coating of active material, identification material and insulating material, ensuring the alignment between the three, and by using the same material for the insulating material and the identification material, the early coating preparation work can be effectively simplified and the coating efficiency of the battery electrode can be improved.

[0025] In one optional embodiment, the partition structure is triangular prism-shaped, and one side of the partition structure is located on the plane where the outlet of the fourth flow channel is located. By providing the partition structure in a triangular prism shape and positioning one side of the partition structure on the plane where the outlet of the fourth flow channel is located, one edge of the triangular prism is ensured to face the interior of the fourth flow channel, thereby reducing the pressure exerted on the partition structure by the material flowing in the fourth flow channel, and ensuring the stability of the partition structure.

[0026] In one optional embodiment, the coating structure includes a first printing groove and a second printing groove disposed circumferentially on the annular side surface of the backing roller. The first printing groove and the second printing groove are spaced apart from each other. The first printing groove is used to accommodate the active material, and the second printing groove is used to accommodate the identification material. When the backing roller rotates, it drives the electrode body to move on its surface. Through the mutual contact between the active material in the first printing groove and the identification material in the second printing groove on the backing roller surface and the electrode body, the active material and the identification material are simultaneously printed and coated on the electrode body surface, and the alignment of the active material and the identification material coating can be effectively ensured.

[0027] According to another aspect of the present application, a battery cell is also provided, comprising the battery pole piece in any of the above-mentioned methods.

[0028] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0030] Figure 1 A schematic diagram of the structure of a vehicle provided in an embodiment of the present application;

[0031] Figure 2 A schematic diagram of the explosion structure of a battery provided in an embodiment of the present application;

[0032] Figure 3 A schematic diagram of the explosion structure of a battery cell provided in an embodiment of the present application;

[0033] Figure 4 A schematic structural diagram of one side of a section of a battery electrode provided in an embodiment of the present application;

[0034] Figure 5 A schematic structural diagram of the other side of one section of a battery electrode provided in an embodiment of the present application;

[0035] Figure 6 A schematic structural diagram of one side of a section of a battery electrode provided by another embodiment of the present application;

[0036] Figure 7 A schematic structural diagram of the other side of one section of a battery electrode provided by another embodiment of the present application;

[0037] Figure 8 A schematic structural diagram of one side of a section of a battery electrode provided by another embodiment of the present application;

[0038] Figure 9 A schematic structural diagram of the other side of a section of a battery electrode provided by another embodiment of the present application;

[0039] Figure 10 A schematic cross-sectional view of a battery electrode provided in another embodiment of the present application;

[0040] Figure 11 A schematic flow chart of a battery electrode coating method according to an embodiment of the present application;

[0041] Figure 12 A schematic flow chart of a battery electrode coating method provided in another embodiment of the present application;

[0042] Figure 13 A schematic flow chart of a battery electrode coating method provided in another embodiment of the present application;

[0043] Figure 14 A schematic flow chart of a battery electrode coating method provided in another embodiment of the present application;

[0044] Figure 15 A schematic side view of the battery electrode coating equipment provided in an embodiment of the present application;

[0045] Figure 16 A schematic top view of the battery electrode coating equipment provided in an embodiment of the present application;

[0046] Figure 17 A schematic top view of a battery electrode coating device according to another embodiment of the present application;

[0047] Figure 18 A schematic structural diagram of a battery electrode coating device provided in another embodiment of the present application.

[0048] The accompanying drawings in the specific implementation manner are as follows:

[0049] Vehicles 1000;

[0050] Battery 100, controller 200, motor 300;

[0051] Box body 10, first part 11, second part 12;

[0052] Battery cell 20, end cap 21, electrode terminal 21a, housing 22, battery cell assembly 23, tab 23a;

[0053] Battery electrode 231, electrode body 2310, active material layer 2311, conductive adhesive layer 2311a, active layer 2311b, identification layer 2312, identification tape 2313;

[0054] Battery electrode coating equipment 500, back roller 510, coating structure 520, first coating head 521, first flow channel 5211, second flow channel 5212, second coating head 522, third flow channel 5221, fourth flow channel 5222, partition structure 5223, first outlet 5224, second outlet 5225, first printing groove 523, second printing groove 524. DETAILED DESCRIPTION

[0055] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0056] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0057] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0058] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0059] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0060] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0061] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0062] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0063] With the development of science and technology and the increasing application of power batteries, batteries are required to have better quality and more powerful performance. The optimization of battery performance is largely achieved by asymmetric coating of active materials on both sides of the electrodes in the battery cell assembly.

[0064] The inventors of this application noticed that in an automated production line, a large number of electrodes are produced, and after the two sides of the electrode are asymmetrically coated, it is impossible to directly distinguish and identify the two unevenly coated sides of the electrode by a machine or the naked eye. Therefore, the two unevenly coated sides of the battery electrode will be incorrectly distinguished, resulting in errors in the subsequent assembly of the battery electrode and unqualified battery production.

[0065] Based on this, the present application proposes a battery electrode, a battery electrode coating method, a battery electrode coating device and a battery cell, in which a coating is formed by combining an active material layer and an identification layer on the two surfaces of the electrode body, and by setting the coatings on the two surfaces of the electrode body to different shapes or positions, the two sides of the battery electrode with uneven coating can be identified and distinguished, thereby ensuring the accuracy of identification of the two sides of the battery electrode.

[0066] The battery disclosed in the embodiments of the present application can be used in, but is not limited to, electrical devices such as vehicles, ships, or aircraft.

[0067] The present invention provides an electric device that uses a battery as a power source. The electric device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, etc. The electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0068] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device according to an embodiment of the present application.

[0069] See also Figure 1 , Figure 1 A schematic structural diagram of a vehicle 1000 provided for some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000. The battery 100 may be provided at the bottom, head or tail of the vehicle 1000. The battery 100 may be used to power the vehicle 1000. For example, the battery 100 may serve as an operating power source for the vehicle 1000. The vehicle 1000 may further include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to power the motor 300, for example, to meet the power requirements for starting, navigating and driving the vehicle 1000.

[0070] In some embodiments of the present application, the battery 100 can serve not only as an operating power source for the vehicle 1000, but also 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.

[0071] See also Figure 2 , Figure 2This is a schematic diagram of an exploded structure of a battery 100 provided in some embodiments of the present application. The battery 100 includes a housing 10 and a battery cell 20, with the battery cell 20 housed within the housing 10. The housing 10 is used to provide a storage space for the battery cell 20 and can have various structures. In some embodiments, the housing 10 can include a first portion 11 and a second portion 12, which overlap each other and together define a storage space for the battery cell 20. The second portion 12 can be a hollow structure with one end open. The first portion 11 can be a plate-like structure, with the first portion 11 overlapping the open side of the second portion 12, so that the first portion 11 and the second portion 12 together define a storage space. The first portion 11 and the second portion 12 can also be hollow structures with one end open, with the open side of the first portion 11 overlapping the open side of the second portion 12. Of course, the housing 10 formed by the first portion 11 and the second portion 12 can have various shapes, such as a cylinder, a rectangular parallelepiped, etc.

[0072] In the battery 100, there may be multiple battery cells 20, and the multiple battery cells 20 may be connected in series, in parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 may be directly connected in series, in parallel, or in a hybrid connection, and then the entire battery cell 20 may be housed within the housing 10. Alternatively, the battery 100 may be constructed by first connecting multiple battery cells 20 in series, in parallel, or in a hybrid connection to form a battery module, which is then connected in series, in parallel, or in a hybrid connection to form a complete battery module, and then housed within the housing 10. The battery 100 may also include other structures, such as a busbar assembly for electrically connecting the multiple battery cells 20.

[0073] Each battery cell 20 may be a secondary battery or a primary battery, and may also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 20 may be cylindrical, flat, rectangular, or in other shapes.

[0074] See also Figure 3 , Figure 3 The following is a schematic diagram of the exploded structure of the battery cell 20 in the battery 100 provided in some embodiments of the present application. The battery cell 20 refers to the smallest unit that makes up the battery. Figure 3 The battery cell 20 includes an end cover 21, a shell 22, a battery cell assembly 23 and other functional components.

[0075] The end cap 21 is a component that covers the opening of the housing 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 match the housing 22. Optionally, the end cap 21 can be made of a material with a certain hardness and strength (such as an aluminum alloy). This prevents the end cap 21 from deforming when subjected to compression or collision, giving the battery cell 20 greater structural strength and improved safety. The end cap 21 can be provided with functional components such as electrode terminals 21a. The electrode terminals 21a can be used to electrically connect to the battery cell assembly 23 to output or input electrical energy to the battery cell 20. In some embodiments, the end cap 21 can also be provided with a pressure relief mechanism for relieving 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 a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application are not particularly limited in this regard. In some embodiments, an insulating member may be provided inside the end cap 21 to isolate the electrical connection components in the housing 22 from the end cap 21 to reduce the risk of short circuit. For example, the insulating member may be made of plastic, rubber, or the like.

[0076] The housing 22 is a component that cooperates with the end cap 21 to form the internal environment of the battery cell 20. This internal environment can be used to accommodate the battery cell assembly 23, electrolyte, and other components. The housing 22 and end cap 21 can be separate components. An opening can be provided in the housing 22, and the end cap 21 is placed over the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 21 and housing 22 can be integrated. Specifically, the end cap 21 and housing 22 can form a common connection surface before other components are inserted into the housing. When the interior of the housing 22 needs to be enclosed, the end cap 21 is placed over the housing 22. The housing 22 can have a variety of shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the housing 22 can be determined based on the specific shape and size of the battery cell assembly 23. The housing 22 can be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this embodiment of the present application does not impose any specific limitations on this.

[0077] The battery cell assembly 23 is a component in the battery cell 20 where electrochemical reactions occur. One or more battery cell assemblies 23 may be contained in the shell 22. The battery cell assembly 23 is mainly formed by winding or stacking positive and negative electrode sheets, and a separator is usually provided between the positive and negative electrode sheets. The parts of the positive and negative electrode sheets with active substances constitute the main body of the battery cell assembly, and the parts of the positive and negative electrode sheets without active substances each constitute a tab 23a. The positive and negative electrode tabs may be located together at one end of the main body or respectively at both ends of the main body. During the charge and discharge process of the battery, the positive electrode active substance and the negative electrode active substance react with the electrolyte, and the tabs 23a connect the electrode terminals to form a current loop.

[0078] According to one aspect of the embodiment of the present application, a battery electrode is provided. Figure 4 and Figure 5 , Figure 4 FIG. 2 shows the structure of one side of a section of a battery electrode 231 provided in one embodiment of the present application. Figure 5 Figure 2 shows the structure of the other side of a section of a battery electrode 231 provided in one embodiment of the present application. Battery electrode 231 includes an electrode body 2310, with active material layers 2311 disposed on both surfaces. Electrode 231 also includes an identification layer 2312 disposed on at least one surface, with the coating having different shapes or positions on the two surfaces.

[0079] Taking a lithium-ion battery as an example, the active material layers on the battery electrode include a positive electrode material layer and a negative electrode material layer formed by coating. The positive electrode material is generally lithium iron phosphate, and the negative electrode material is generally natural graphite, artificial graphite, etc. The identification layer 2312 can be formed by coating with a colloidal material that is easy to identify and insulating.

[0080] The coating on the surface of the pole piece body 2310 refers to a coating structure composed of an active material layer 2311 and an identification layer 2312 on one surface of the pole piece body 2310. Specifically, the shapes or positions of the coatings on the two surfaces are different. Specifically, the identification layer 2312 is provided on only one surface of the pole piece body 2310, and the identification layer 2312 is not provided on the other surface, so that the two surfaces of the pole piece body 2310 can be visually distinguished by the naked eye or a machine. The shapes or positions of the coatings on the two surfaces are different. Alternatively, the identification layer 2312 is provided on both surfaces of the pole piece body 2310, but the shapes or positions of the identification layers 2312 on the two surfaces are different, so that the two surfaces of the pole piece body 2310 can be identified and distinguished by the naked eye or a machine.

[0081] By setting an identification layer 2312 on at least one surface of the electrode body 2310 and making the shapes or positions of the coatings on the two surfaces different, the two surfaces of the electrode body 2310 can be accurately identified and distinguished by the naked eye or a machine, thereby ensuring that the battery electrode 231 can be accurately positioned and assembled in the subsequent production.

[0082] Please continue reading Figure 4 and Figure 5 According to some embodiments of the present application, the identification layer 2312 is only provided on one surface of the pole piece body 2310 .

[0083] By providing an active material layer 2311 and an identification layer 2312 on one surface of the electrode body 2310 and only providing the active material layer 2311 on the other surface, the two sides of the battery electrode 231 can be distinguished and identified.

[0084] See also Figure 6 and Figure 7 , Figure 6 FIG. 2 shows the structure of one side of a section of a battery electrode 231 provided in another embodiment of the present application. Figure 7 FIG2 shows the structure of the other side of a section of a battery electrode 231 provided in another embodiment of the present application. According to some embodiments of the present application, an identification layer 2312 is provided on both surfaces of the electrode body 2310, and the shape or position of the identification layer 2312 on the two surfaces are different.

[0085] like Figure 6 and Figure 7 As shown in , the two sides of the battery electrode 231 can be distinguished by setting the positions and widths of the identification layers 2312 on the two surfaces of the electrode body 2310 to be different.

[0086] It is understood that in some other embodiments of the present application, the two sides of the battery electrode 231 can also be distinguished by setting the shapes of the identification layers 2312 on the two surfaces of the electrode body 2310 to be different. For example, the identification layer 2312 on one side can be set to a strip-shaped rectangular shape, and the identification layer 2312 on the other side can be set to a strip-shaped wavy shape. The specific shape, position, and size of the identification layers 2312 on the two surfaces of the electrode body 2310 are not limited, as long as the two sides can be distinguished and identified.

[0087] By setting the shapes or positions of the identification layers 2312 on the two surfaces of the electrode body 2310 to be different, the two sides of the battery electrode 231 can be distinguished and identified.

[0088] Please refer again Figure 4According to some embodiments of the present application, on a surface of the pole piece body 2310 on which an identification layer 2312 is provided, the identification layer 2312 and the active material layer 2311 extend along a first direction and are spaced apart along a second direction. The first direction and the second direction are both located on the surface of the pole piece body 2310 and are perpendicular to each other.

[0089] like Figure 4 As shown in , the first direction is the x-axis direction in the figure, and the second direction is the y-axis direction in the figure.

[0090] It should be noted that Figure 4 and Figure 5 Only one section of the battery electrode 231 is shown. The battery electrode 231 can be a wound battery electrode or a stacked battery electrode. The extending direction of the battery electrode 231 (that is, the extending direction of the identification layer 2312 and the active material layer 2311) is Figure 4 The x-axis direction.

[0091] Specifically, on the surface provided with the identification layer 2312, the identification layer 2312 may be as follows: Figure 4 As shown in FIG, the marking layer 2312 is spaced apart and disposed on both sides of the active material layer 2311. It is understandable that the marking layer 2312 can also be disposed in contact with the active material layer 2311, or only spaced apart and disposed on one side of the active material layer 2311.

[0092] By extending the identification layer 2312 and the active material layer 2311 along the first direction, the appearance of the battery electrode 231 is ensured to be neat and the coating of the identification layer 2312 and the active material layer 2311 is facilitated. By spacing the identification layer 2312 and the active material layer 2311 along the second direction, it is possible to prevent the identification layer 2312 from contacting the active material layer 2311, making it difficult to identify the identification layer 2312 and thus making it difficult to distinguish the two sides of the battery electrode 231.

[0093] See also Figure 8 and Figure 9 , Figure 8 FIG. 2 shows the structure of one side of a section of a battery electrode 231 provided in another embodiment of the present application. Figure 9 2 shows the structure of the other side of a section of a battery electrode 231 provided in another embodiment of the present application. According to some embodiments of the present application, a marking layer 2312 is provided on a surface of the electrode body 2310. The marking layer 2312 and the active material layer 2311 extend along a first direction. The marking layer 2312 includes at least two marking bands 2313. The at least two marking bands 2313 are spaced apart along a second direction. The first direction and the second direction are both located on the surface of the electrode body 2310 and are perpendicular to each other.

[0094] like Figure 8As shown in FIG9 , one side of the battery electrode 231 is provided with two spaced apart identification bands 2313 on either side of the active material layer 2311, with one identification band 2313 contacting the edge of the active material layer 2311. The other side of the battery electrode 231 is provided with one identification band 2313 on either side of the active material layer 2311, with the identification bands 2313 contacting the edge of the active material layer 2311. Providing identification bands 2313 on both sides of the battery electrode 231 in contact with the edges of the active material layer 2311 provides insulation protection for both sides of the active material layer 2311, provides good working conditions for the active material layer 2311, increases the service life of the battery electrode 231, and prevents short circuit failures in the battery electrode 231.

[0095] The marking tape 2313 may be made of a colloidal material with insulating properties to ensure insulation protection for the edge of the active material layer 2311 .

[0096] By setting the identification layer 2312 as two separated identification strips 2313, and one of the identification strips 2313 can be in contact with the active material layer 2311, while ensuring that both sides of the battery electrode 231 can be quickly identified, it can also insulate both sides of the active material layer 2311.

[0097] According to some embodiments of the present application, the identification layer 2312 is an insulating layer.

[0098] Specifically, the marking layer 2312 can use materials such as boehmite and alumina as the insulating main material, and use materials such as polyvinylidene fluoride, styrene-butadiene rubber, polyacrylic acid, and polyamide as the colloid material to form a coating with both marking and insulating capabilities.

[0099] By setting the identification layer 2312 as an insulating layer, the identification layer 2312 coated on the electrode body 2310 can not only realize the identification of both sides of the battery electrode 231 , but also play the role of insulating and protecting the active material layer 2311 on the electrode body 2310 .

[0100] See also Figure 10 The figure shows a cross-sectional structure of a battery electrode 231 provided in another embodiment of the present application. According to some embodiments of the present application, the active material layer 2311 includes a conductive adhesive layer 2311a and an active layer 2311b on the surface of the electrode body 2310, and the identification layer 2312 is the conductive adhesive layer 2311a.

[0101] The conductive adhesive layer 2311a can use conductive carbon black as the conductive main material, and use polyvinylidene fluoride, styrene-butadiene rubber, polyacrylic acid, polyamide and other materials as the colloid material.

[0102] For some battery electrodes 231, the active material layer 2311 thereon needs to be coated with a conductive adhesive layer 2311a on the surface of the battery electrode 231 first and then with the active layer 2311b. In order to improve the coating efficiency of the battery electrode 231, the identification layer 2312 is also set as the conductive adhesive layer 2311a. The identification layer 2312 can be coated at the same time as the conductive adhesive layer 2311a in the identification layer 2312 is coated, thereby improving the processing efficiency of the battery electrode 231, and setting the identification layer 2312 as the conductive adhesive layer 2311a reduces the types of coatings, thereby reducing the preparation work before coating.

[0103] According to some embodiments of the present application, the pole piece body 2310 is a single-layer current collector or a composite current collector.

[0104] A current collector is a structure or component made of metal foil, such as copper foil or aluminum foil, that collects current. A single-layer current collector consists of a single layer of metal foil, while a composite current collector is made of multiple layers of metal foil.

[0105] Single-layer current collectors or composite current collectors are used to collect the current generated by the battery active material to form a larger current output. Therefore, the current collector should be in full contact with the active material layer 2311, and the internal resistance should be as small as possible.

[0106] According to another aspect of the embodiment of the present application, a battery electrode coating method is provided. For details, please refer to Figure 11, which shows the process of the battery electrode coating method provided by an embodiment of the present application. The battery electrode includes a electrode body, and the battery electrode coating method includes:

[0107] S10: coating active materials on both surfaces of the electrode body to form active material layers;

[0108] S20: coating a marking material on at least one surface to form a marking layer, so that the coating shapes or positions on the two surfaces are different, thereby forming a battery electrode.

[0109] Specifically, the active material layer and the identification layer can be coated on the surface of the electrode body by cooperating with a coating head and a back roller, or by a back roller with a printing function.

[0110] By coating at least one surface of the electrode body with an identification material to form an identification layer, the shape or position of the coating on the two surfaces is made different, thereby enabling the two surfaces of the electrode body to be accurately identified and distinguished by the naked eye or a machine, ensuring that the battery electrode can be accurately positioned and assembled in the subsequent production.

[0111] According to some embodiments of the present application, the marking material is coated on only one surface of the pole piece body to form a marking layer.

[0112] By coating the active material layer and the identification layer on one surface of the electrode body and coating only the active material layer on the other surface, the two sides of the battery electrode can be distinguished and identified.

[0113] According to some embodiments of the present application, a marking material is coated on both surfaces of the pole piece body to form a marking layer, and the shapes or positions of the marking layers on the two surfaces are different.

[0114] By setting the shapes or positions of the identification layers on the two surfaces of the electrode body to be different, the two sides of the battery electrode can be distinguished and identified.

[0115] See also Figure 12 , the figure shows the process of a battery electrode coating method provided by another embodiment of the present application. According to some embodiments of the present application, step S10 includes:

[0116] S11: coating active material on both surfaces of the electrode body along a first direction to form an active material layer;

[0117] Step S20 includes:

[0118] S21: coating a marking material on at least one surface of the electrode body along a first direction to form a marking layer, wherein the marking layer and the active material layer are spaced apart along a second direction, and the first direction and the second direction are both located on the surface of the electrode body and are perpendicular to each other.

[0119] By applying the identification layer and active material layer along the first direction, the appearance of the battery electrode is kept neat and the application of the identification layer and active material layer is facilitated. By spacing the identification layer and active material layer along the second direction, it is possible to avoid contact between the identification layer and the active material layer, making it difficult to identify the identification layer and thus making it difficult to distinguish the two sides of the battery electrode.

[0120] See also Figure 13 , the figure shows the process of a battery electrode coating method provided by another embodiment. According to some embodiments of the present application, step S10 includes:

[0121] S12: coating active material on both surfaces of the electrode body along a first direction to form active material layers;

[0122] Step S20 includes:

[0123] S22: Applying identification material on at least one surface of the pole piece body along a first direction to form at least two identification bands, and at least two identification bands are spaced apart along a second direction, and the first direction and the second direction are both located on the surface of the pole piece body and are perpendicular to each other.

[0124] By placing identification tape on the edges of the active material layers on both sides of the battery electrode, insulation protection is achieved on both sides of the active material layer, providing good working conditions for the active material layer, which is beneficial to increasing the service life of the battery electrode and preventing short circuit failures in the battery electrode. The identification tape on one side of the battery electrode is separated from the identification layer to ensure quick identification of both sides of the battery electrode.

[0125] By coating the identification layer into two separated identification bands, and one of the identification bands can be coated in contact with the active material layer, while ensuring that both sides of the battery electrode can be quickly identified, it can also insulate both sides of the active material layer.

[0126] See also Figure 14 , the figure shows the process of a battery electrode coating method provided by another embodiment of the present application. According to some embodiments of the present application, step S10 includes:

[0127] S13: Coating a conductive adhesive layer material and an active layer material on two surfaces of the electrode body to form an active material layer.

[0128] Step S20 includes:

[0129] S23: Coating a conductive adhesive layer material on at least one surface of the electrode body to form a marking layer.

[0130] For some battery electrodes, the active material layer on it needs to be coated with a conductive adhesive layer on the surface of the battery electrode first and then the active layer. In order to improve the coating efficiency of the battery electrode, the identification layer is also set as a conductive adhesive layer. The identification layer can be coated at the same time as the conductive adhesive layer in the identification layer, thereby improving the coating efficiency of the battery electrode. In addition, setting the identification layer as a conductive adhesive layer reduces the types of coatings, thereby reducing the preparation work before coating.

[0131] According to another aspect of the embodiment of the present application, a battery electrode coating device is also provided. Figure 15 The figure shows the structure of a battery electrode coating device 500 provided in one embodiment of the present application. The battery electrode 231 includes a electrode body 2310. The battery electrode coating device 500 includes: a back roller 510 and a coating structure 520. The back roller 510 is used to drive the battery electrode 231 to move. The coating structure 520 is arranged on one side of the back roller 510 and is used to coat active material on both surfaces of the electrode body 2310 to form an active material layer 2311, and to coat a marking material on at least one surface to form a marking layer 2312. The shapes or positions of the coatings on the two surfaces are different.

[0132] The back roller 510 is cylindrical, and the battery pole piece 231 is placed on the back roller 510 . The rotation of the back roller 510 drives the battery pole piece 231 to move and coat.

[0133] The coating structure 520 has a coating outlet, which is aligned with one side of the back roller 510 . By adding coating into the coating structure 520 , the coating is pushed by pressure and squeezed out from the coating outlet and coated on the battery electrode 231 .

[0134] By setting up a back roller 510, the movement of the battery electrode 231 is controlled, and the active material and identification material are coated on the surface of the electrode body 2310 through the coating structure 520, and the shapes or positions of the coatings on the two surfaces are made different, so that the two surfaces of the electrode body 2310 can be accurately identified and distinguished by the naked eye or a machine, ensuring that the battery electrode 231 can be accurately positioned and assembled in the subsequent production.

[0135] In some embodiments of the present application, multiple coating outlets can be provided on the coating structure 520 to achieve simultaneous coating of active material and identification material on one side of the battery electrode, thereby reducing the time cost consumed in the production of the battery electrode and effectively ensuring the relative position of the active material and identification material on the battery electrode 231, thereby improving the production qualification rate of the battery electrode 231.

[0136] See also Figure 16 The figure shows a top view of a first coating head 521 in a battery electrode coating apparatus 500 provided in one embodiment of the present application. According to some embodiments of the present application, the coating structure 520 includes a first coating head 521, which is aligned with one side of the backing roller 510 and is used to coat the electrode body 2310 on the backing roller 510. A first flow channel 5211 and a second flow channel 5212 are provided in the first coating head 521. The outlet of the first flow channel 5211 is spaced apart from the outlet of the second flow channel 5212. The first flow channel 5211 is used to circulate active material, and the second flow channel 5212 is used to circulate marking material.

[0137] Specifically, when coating one side of the electrode body 2310, the active material is fed into the first flow channel 5211, and the identification material is fed into the second flow channel 5212. The active material and the identification material are simultaneously extruded from the outlets of the first and second flow channels 5211, 5212, and coated on the electrode body 2310, thereby achieving simultaneous coating of the active material and the identification material. When coating the other side of the electrode body 2310, the active material is fed only into the first flow channel 5211, extruded from the outlet of the first flow channel 5211, and coated on the electrode body 2310, thereby achieving coating of the active material on the other side of the electrode body 2310.

[0138] The first coating head 521 is aligned with one side of the back roller 510 so that the material extruded from the first coating head 521 can be smoothly coated on the pole piece body 2310. By setting a first flow channel 5211 and a second flow channel 5212 in the first coating head 521, the first flow channel 5211 is used to circulate the active material, and the second flow channel 5212 is used to circulate the identification material, thereby realizing the simultaneous coating of the active material and the identification material, thereby effectively ensuring the alignment between the identification material and the active material coated on the pole piece body 2310, thereby improving the qualified rate of the pole piece body 2310 production, ensuring the neat appearance of the pole piece body 2310, and facilitating easy identification of both sides of the battery pole piece 231.

[0139] See also Figure 17 , the figure shows the structure of the second coating head 522 in the battery electrode coating equipment 500 provided in another embodiment of the present application after cross-section. According to some embodiments of the present application, the coating structure 520 includes a second coating head 522, and the second coating head 522 is aligned with one side of the back roller 510, and is used to coat the electrode body 2310 on the back roller 510. A third flow channel 5221 and a fourth flow channel 5222 are provided in the second coating head 522, and the third flow channel 5221 is used to circulate active materials, and the fourth flow channel 5222 is used to circulate insulating materials. The outlet of the fourth flow channel 5222 is provided with a partition structure 5223, and the partition structure 5223 divides the outlet of the fourth flow channel 5222 into a first outlet 5224 and a second outlet 5225 separated from each other, and the edge of the outlet of the third flow channel 5221 is in contact with the edge of the first outlet 5224.

[0140] Specifically, after the insulating material is input into the fourth flow channel 5222 , the insulating material is extruded through the first outlet 5224 and the second outlet 5225 to form two identification bands 2313 on the electrode body 2310 .

[0141] The partition structure 5223 can be integrally formed with the shell of the second coating head 522 to ensure the structural strength of the partition structure 5223 and avoid the partition structure 5223 from being broken due to excessive squeezing force of the insulating material.

[0142] By setting a third flow channel 5221 and a fourth flow channel 5222 in the second coating head 522, the third flow channel 5221 is used to circulate active material, and the fourth flow channel 5222 is used to circulate insulating material, so as to achieve simultaneous coating of active material and insulating material, ensure the alignment and effectiveness of the contact between the identification tape 2313 on the electrode body 2310 and the active material layer 2311, so that the insulating material can provide reliable and effective insulating protection for the active material. By setting a partition structure 5223 at the outlet of the fourth flow channel 5222, the outlet of the fourth flow channel 5222 is divided into a first outlet 5224 and a second outlet 5225 separated from each other, thereby effectively simplifying the flow channel structure inside the second coating head 522 and reducing the mold opening cost of the second coating head 522. In addition, by inputting insulating material into the fourth flow channel 5222, the insulating material forms a separated identification band 2313 and an identification layer 2312 on the electrode body 2310 through the first outlet 5224 and the second outlet 5225, respectively, thereby realizing simultaneous coating of active material, identification material and insulating material, ensuring the alignment between the three, and by using the same material for the insulating material and the identification material, the early coating preparation work can be effectively simplified and the coating efficiency of the battery electrode 231 can be improved.

[0143] Please continue reading Figure 16 According to some embodiments of the present application, the partition structure 5223 is in the shape of a triangular prism, and one side surface is located on the plane where the outlet of the fourth flow channel 5222 is located.

[0144] By setting the partition structure 5223 in a triangular prism shape and setting one side thereof on the plane where the outlet of the fourth flow channel 5222 is located, it is ensured that one of the edges of the triangular prism faces the interior of the fourth flow channel 5222, thereby reducing the pressure exerted on the partition structure 5223 by the material flowing in the fourth flow channel 5222, thereby ensuring the stability of the partition structure 5223.

[0145] See also Figure 18 The figure shows the structure of a battery electrode coating apparatus 500 according to another embodiment of the present application. According to some embodiments of the present application, the coating structure 520 includes a first printing groove 523 and a second printing groove 524 circumferentially disposed on the annular side surface of the backing roller 510. The first printing groove 523 and the second printing groove 524 are spaced apart from each other. The first printing groove 523 is used to accommodate the active material, and the second printing groove 524 is used to accommodate the marking material.

[0146] During the coating process of the battery electrode 231, active material is set in the first printing groove 523 and identification material is set in the second printing groove 524. Considering that the active material and identification material may drip during the rotation of the back roller 510, the first printing groove 523 and the second printing groove 524 can be set to a smaller depth, and the active material and identification material can be coated on the surface of the first printing groove 523 and the second printing groove 524 to form a thinner layer. A material receiving box can also be set at the bottom of the back roller 510 to collect the dripping material in the receiving box for secondary use.

[0147] When the back roller 510 rotates, it drives the pole piece body 2310 to move on its surface. Through the mutual contact between the active material in the first printing groove 523 on the surface of the back roller 510 and the marking material in the second printing groove 524 and the pole piece body 2310, the active material and the marking material on the surface of the pole piece body 2310 are printed and coated simultaneously, and the alignment of the coating of the active material and the marking material can be effectively guaranteed.

[0148] For the implementation method in which the above-mentioned active material includes a conductive adhesive layer material and an active layer material, during the first printing and coating, the conductive adhesive layer material can be set in both the first printing groove 523 and the second printing groove 524, and the conductive adhesive layer material printed and coated on the electrode body 2310 through the second printing groove 524 is used as an identification material. During the second printing and coating, the active material is only set in the first printing groove 523 to realize the printing and coating of the active material on the surface of the conductive adhesive layer material.

[0149] According to another aspect of an embodiment of the present application, a battery cell is provided, comprising the above-mentioned battery electrode 231 .

[0150] In the battery cell, an active material layer 2311 and an identification layer 2312 are provided on one side of the battery electrode 231, and only the active material layer 2311 is provided on the other side, so as to realize the distinction and identification of the two sides of the battery electrode 231. In addition, by providing the identification layer 2312 on at least one side of the active material layer 2311 and separating it from the active material layer 2311, it is convenient for machines or humans to distinguish and identify the two sides of the battery electrode 231. The extension directions of the identification layer 2312 and the active material layer 2311 are provided in parallel to each other, thereby ensuring the stability of the active material layer 2311 when the battery electrode 231 is working, and effectively preventing the identification layer 2312 and the active material layer 2311 from mixing, which may cause the performance of the active material layer 2311 to deteriorate or even fail.

[0151] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery electrode, comprising a electrode body, wherein two surfaces of the electrode body are respectively provided with coatings, and the coatings on each surface comprise an active material layer; characterized in that: The coating on at least one of the surfaces further includes an identification layer, and the shapes of the coatings on the two surfaces are different or the positions of the identification layers on the two surfaces are different; along the second direction, the identification layer is located on at least one side of the active material layer; the second direction is perpendicular to the extension direction of the active material layer; the identification layer is formed by an identification material coated on the surface.

2. The battery electrode according to claim 1, characterized in that: The identification layer is provided on only one of the surfaces.

3. The battery electrode according to claim 1, characterized in that: The marking layers are respectively arranged on the two surfaces, and the shapes or positions of the marking layers on the two surfaces are different.

4. The battery electrode according to any one of claims 1 to 3, characterized in that: On the surface provided with the identification layer, the identification layer and the active material layer extend along a first direction and are spaced apart along a second direction. The first direction and the second direction are both located on the surface and perpendicular to each other.

5. The battery electrode according to any one of claims 1 to 3, characterized in that: On a surface provided with the identification layer, the identification layer and the active material layer extend along a first direction, the identification layer includes at least two identification bands, and at least two of the identification bands are arranged at intervals along a second direction, and the first direction and the second direction are both located on the surface and perpendicular to each other.

6. The battery electrode according to any one of claims 1 to 3, characterized in that: The identification layer is an insulating layer.

7. The battery electrode according to any one of claims 1 to 3, characterized in that: The active material layer includes a conductive adhesive layer and an active layer in sequence on the surface; and the marking layer is a conductive adhesive layer.

8. The battery electrode according to any one of claims 1 to 3, characterized in that: The pole piece body is a single-layer current collector or a composite current collector.

9. A method for coating a battery pole piece, wherein the battery pole piece comprises a pole piece body, characterized in that: include: Active material is coated on both surfaces of the pole piece body to form active material layers; A marking material is coated on at least one of the surfaces to form a marking layer, so that coatings are formed on both surfaces, the coating on each surface includes an active material layer, the coating on at least one surface also includes a marking layer, and the shapes of the coatings on the two surfaces are different or the positions of the marking layers on the two surfaces are different, and along a second direction, the marking layer is located on at least one side of the active material layer, and the second direction is perpendicular to the extension direction of the active material layer.

10. The battery pole piece coating method according to claim 9, characterized in that: The marking material is coated only on one of the surfaces to form the marking layer.

11. The battery pole piece coating method according to claim 9, characterized in that: The marking material is coated on the two surfaces respectively to form the marking layer, and the shapes or positions of the marking layers on the two surfaces are different.

12. The battery pole piece coating method according to any one of claims 9 to 11, characterized in that: The active material is coated on both surfaces of the pole piece body to form an active material layer, comprising: coating the active material on the two surfaces along a first direction to form the active material layer; The step of coating the marking material on at least one of the surfaces to form a marking layer comprises: The marking material is coated on at least one of the surfaces along the first direction to form the marking layer. The marking layer and the active material layer are spaced apart along the second direction. The first direction and the second direction are both located on the surface and perpendicular to each other.

13. The battery pole piece coating method according to any one of claims 9 to 11, characterized in that: The active material is coated on both surfaces of the pole piece body to form an active material layer, comprising: coating the active material on the two surfaces along a first direction to form the active material layer; The step of coating the marking material on at least one of the surfaces to form a marking layer comprises: The marking material is coated on at least one of the surfaces along a first direction to form at least two marking bands, and the at least two marking bands are spaced apart along a second direction. The first direction and the second direction are both located on the surface and perpendicular to each other.

14. The battery pole piece coating method according to any one of claims 9 to 11, characterized in that: The active material is coated on both surfaces of the pole piece body to form an active material layer, comprising: Sequentially coating the conductive adhesive layer material and the active layer material on the two surfaces to form the active material layer; The step of coating the marking material on at least one of the surfaces to form a marking layer comprises: The conductive adhesive layer material is coated on at least one of the surfaces to form the marking layer.

15. A battery pole piece coating device, wherein the battery pole piece comprises a pole piece body, characterized in that: include: A back roller, used for driving the pole piece body to move; A coating structure is provided on one side of the back roller, and is used to coat active materials on the two surfaces of the pole piece body to form active material layers, and to coat identification materials on at least one of the surfaces to form an identification layer, so that coatings are formed on both surfaces, the coatings on each of the surfaces include an active material layer, the coatings on at least one of the surfaces also include an identification layer, and the shapes of the coatings on the two surfaces are different or the positions of the identification layers on the two surfaces are different, and along the second direction, the identification layer is located on at least one side of the active material layer, and the second direction is perpendicular to the extension direction of the active material layer.

16. The battery pole piece coating equipment according to claim 15, characterized in that: The coating structure includes a first coating head, which is aligned with one side of the back roller and is used to coat the pole piece body on the back roller; A first flow channel and a second flow channel are provided in the first coating head. The first flow channel is used to circulate the active material, and the second flow channel is used to circulate the marking material.

17. The battery pole piece coating equipment according to claim 15, characterized in that: The coating structure includes a second coating head, which is aligned with one side of the back roller and is used to coat the pole piece body on the back roller; The second coating head is provided with a third flow channel and a fourth flow channel, the third flow channel is used to circulate the active material, and the fourth flow channel is used to circulate the marking material; A partition structure is provided at the outlet of the fourth flow channel, which divides the outlet of the fourth flow channel into a first outlet and a second outlet that are separated from each other. The edge of the outlet of the third flow channel contacts the edge of the first outlet.

18. The battery pole piece coating equipment according to claim 17, characterized in that: The partition structure is in a triangular prism shape, and one side surface of the partition structure is located on the plane where the outlet of the fourth flow channel is located.

19. The battery pole piece coating equipment according to claim 15, characterized in that: The coating structure includes a first printing groove and a second printing groove arranged circumferentially on the annular side surface of the back roller, the first printing groove and the second printing groove are arranged apart, the first printing groove is used to accommodate the active material, and the second printing groove is used to accommodate the marking material.

20. A battery cell, characterized in that: A battery pole piece comprising the battery pole piece according to any one of claims 1 to 8.

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