Pole piece and battery

Abstract

The utility model provides a pole piece and a battery, and relates to the technical field of battery energy, the pole piece comprises a pole piece body and an insulating base material, the insulating base material comprises a base material body and a limiting part, the length directions of the pole piece body and the base material body are consistent, and the pole piece body is connected to two opposite surfaces of the base material body; the polarities of the pole piece bodies located on the two faces of the base material body are opposite, the limiting parts are located at least one end of the base material body in the length direction of the base material body, the limiting parts are connected to at least one face of the base material body and extend away from the base material body in the thickness direction of the base material body, and at least one end of the pole piece body in the length direction of the base material body abuts against the limiting parts. The pole piece disclosed by the utility model is not easy to generate an over-voltage or under-voltage problem during cold pressing.

Description

Technical Field

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

[0002] Lithium-ion batteries can provide power for electric vehicles, electric trains, electric bicycles, golf carts and other means of transportation to replace traditional energy sources such as gasoline. They are the main direction of new energy development at present, or provide power for electronic devices such as mobile phones and tablets.

[0003] In the prior art, a lithium-ion battery is composed of a shell, an electrolyte, and a battery cell. The battery cell may include a positive electrode sheet, a negative electrode sheet, and a separator. The positive electrode sheet, the separator, and the negative electrode sheet are sequentially stacked and then wound. During the winding process, it is difficult to align the positive electrode sheet and the negative electrode sheet. The production process is complicated and needs to be optimized. As a result, an amphiphilic electrode sheet that integrates the positive electrode sheet and the negative electrode sheet into one is produced, that is, metal foils are arranged on opposite sides of the insulating layer, and then the positive electrode active material and the negative electrode active material are respectively coated on the two metal foils to simultaneously form a positive electrode coating and a negative electrode coating on the amphiphilic electrode sheet, and then the positive electrode coating and the negative electrode coating are cold pressed to ensure that the compaction density of the amphiphilic electrode sheet meets the requirements.

[0004] However, different pressures are required for cold pressing of the positive electrode coating and the negative electrode coating. If the same pressure is used for cold pressing, one of the positive electrode coating and the negative electrode coating may be over-pressurized or under-pressurized. Utility Model Content

[0005] Based on this, the present application provides a pole piece and a battery, wherein the pole piece is not prone to overvoltage or undervoltage problems during cold pressing.

[0006] In the first aspect, the present application provides a pole piece, which includes a pole piece body and an insulating substrate, the insulating substrate includes a substrate body and a limiting portion, the pole piece body and the substrate body have the same length direction, the pole piece body is connected to two opposite sides of the substrate body, and the polarities of the pole piece bodies located on the two sides of the substrate body are opposite, the limiting portion is located at at least one end of the substrate body along its own length direction, the limiting portion is connected to at least one side of the substrate body and extends away from the substrate body along the thickness direction of the substrate body, and at least one end of the pole piece body along its own length direction abuts against the limiting portion.

[0007] In a possible implementation, in the pole piece provided in the present application, the extension length of the limiting portion along the thickness direction of the substrate body is equal to the thickness of the pole piece body.

[0008] In a possible implementation, the pole piece, the limiting portion and the substrate body provided in the present application are integrally formed.

[0009] In one possible implementation, the pole piece provided in the present application has a groove on the side of the limiting portion facing the pole piece body, the pole piece body includes a current collector and an active material layer, the current collector is connected between the substrate body and the active material layer, and the end of the current collector along its own length direction is inserted into the groove.

[0010] In a possible implementation, the electrode sheet provided by the present application, the current collector includes a first current collector and a second current collector, the active material layer includes a first active material layer and a second active material layer, the first current collector is connected between the substrate body and the first active material layer, and the second current collector is connected between the substrate body and the second active material layer;

[0011] The material of one of the first current collector and the second current collector includes aluminum, and the material of the other includes copper.

[0012] In a possible implementation, the electrode sheet provided by the present application has a first active material layer with a positive polarity, a second active material layer with a negative polarity, a width of the first active material layer less than or equal to a width of the first current collector, a width of the second active material layer greater than or equal to a width of the first current collector, and a width of the first current collector and a width of the second current collector both less than a width of the substrate body;

[0013] The width of the first active material layer is smaller than the width of the second active material layer.

[0014] In a possible implementation, the pole piece, the first current collector and the second current collector provided in the present application are all symmetrically arranged with respect to the midline of the length direction of the substrate body.

[0015] In a possible implementation, the electrode sheet provided in the present application, the current collector and the substrate body are connected by thermal melting;

[0016] The material of the insulating substrate includes at least one of polypropylene, polyester and polyvinyl chloride.

[0017] In a possible implementation, the pole piece provided in the present application includes a pole ear, and the pole ear and the current collector are integrally formed;

[0018] The electrode tabs include a first electrode tab and a second electrode tab, wherein the first electrode tab is connected to the first current collector, and the second electrode tab is connected to the second current collector. The first electrode tab and the second electrode tab are located on one side of the length direction of the substrate body, and the first electrode tab and the second electrode tab are staggered along the length direction of the substrate body.

[0019] In a second aspect, the present application provides a battery, the battery includes a battery cell, the battery cell includes a diaphragm and the pole piece provided in the first aspect, and the diaphragm and the pole piece are stacked.

[0020] The present application provides a pole piece and a battery, wherein the pole piece includes a pole piece body and an insulating substrate, wherein the insulating substrate includes a substrate body and a limiting portion, wherein the pole piece body is used to react with an electrolyte to generate current, the substrate body is used to insulate and isolate the pole piece bodies on two opposite sides of the substrate body, and the limiting portion is used to limit the pressing depth of the pole piece body when the roller pressing device compacts the pole piece body, thereby avoiding the phenomenon of overpressure of the pole piece body when the pressure is large, and avoiding the phenomenon of underpressure of the pole piece body when the pressure is small. Therefore, the pole piece of the present application is not prone to overpressure or underpressure during cold pressing.

[0021] In addition to the technical problems solved by the embodiments of the present application described above, the technical features that constitute the technical solutions, and the beneficial effects brought about by the technical features of these technical solutions, other technical problems that can be solved by the pole pieces and batteries provided by the present application, other technical features included in the technical solutions, and the beneficial effects brought about by these technical features will be further described in detail in the specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 A schematic diagram of the structure of a battery provided in an embodiment of the present application;

[0024] Figure 2 A schematic diagram of the structure of a battery cell in a battery provided in an embodiment of the present application;

[0025] Figure 3 A schematic diagram of the structure of the pole piece provided in the embodiment of the present application;

[0026] Figure 4 A schematic diagram of the structure of the insulating substrate and the pole piece body in the pole piece provided in the embodiment of the present application;

[0027] Figure 5 A schematic diagram of the structure of the insulating substrate in the pole piece provided in the embodiment of the present application;

[0028] Figure 6 for Figure 5 A partial enlarged view of point A in the middle.

[0029] Description of reference numerals:

[0030] 10-battery cell;

[0031] 100-pole piece; 110-pole piece body; 111-current collector; 1111-first current collector; 1112-second current collector; 112-active material layer; 1121-first active material layer; 1122-second active material layer;

[0032] 120-insulating substrate; 121-substrate body; 122-limiting portion; 1221-groove;

[0033] 130-ear; 131-first ear; 132-second ear;

[0034] 200-diaphragm;

[0035] 20- Shell. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme in the embodiment of the present application will be described in more detail below in conjunction with the drawings in the preferred embodiments of the present application. In the drawings, the same or similar reference numerals throughout represent the same or similar parts or parts with the same or similar functions. The described embodiments are part of the embodiments of the present application, not all of the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limitations on the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application. The embodiments of the present application are described in detail below in conjunction with the drawings.

[0037] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, or it can be an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0038] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are orientations or positional relationships based on the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0039] The terms "first", "second", "third" (if any) in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the application described herein can be implemented in an order other than those illustrated or described herein, for example.

[0040] In addition, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product, or display comprising a series of steps or elements is not necessarily limited to those steps or elements explicitly listed, but may include other steps or elements not explicitly listed or inherent to such process, method, product, or display.

[0041] In the prior art, a lithium-ion battery is composed of a shell, an electrolyte, and a battery cell. The battery cell may include a positive electrode sheet, a negative electrode sheet, and a separator. The positive electrode sheet, the separator, and the negative electrode sheet are sequentially stacked and then wound. During the winding process, it is difficult to align the positive electrode sheet and the negative electrode sheet. The production process is complicated and needs to be optimized. As a result, an amphiphilic electrode sheet that integrates the positive electrode sheet and the negative electrode sheet into one is produced, that is, metal foils are arranged on opposite sides of the insulating layer, and then the positive electrode active material and the negative electrode active material are respectively coated on the two metal foils to simultaneously form a positive electrode coating and a negative electrode coating on the amphiphilic electrode sheet, and then the positive electrode coating and the negative electrode coating are cold pressed to ensure that the compaction density of the amphiphilic electrode sheet meets the requirements.

[0042] However, different pressures are required for cold pressing of the positive electrode coating and the negative electrode coating. The pressure required for cold pressing of the positive electrode coating is greater, while the pressure required for cold pressing of the negative electrode coating is smaller. If the pressure of the positive electrode coating is used for cold pressing, the negative electrode coating will be over-pressurized. If the pressure of the negative electrode coating is used for cold pressing, the positive electrode coating will be under-pressurized.

[0043] In view of the above problems, an embodiment of the present application provides a pole piece and a battery, in which a limit portion is set on the insulating substrate to limit the pressing depth of the rolling equipment when cold pressing the pole piece body, thereby avoiding the use of a higher pressure to cause one of the two pole piece bodies to be over-pressurized, or avoiding the use of a lower pressure to cause one of the two pole piece bodies to be under-pressurized.

[0044] The specific implementation of the electrode and battery provided in the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0045] Reference Figure 1 and Figure 2 As shown, an embodiment of the present application provides a battery, the battery includes a battery cell 10, the battery cell 10 includes a pole piece 100 and a separator 200, and the separator 200 and the pole piece 100 are stacked.

[0046] It is understandable that the battery may further include a shell 20 , in which the battery cell 10 and the electrolyte are encapsulated, and the pole piece 100 is coated with an active substance that can react with the electrolyte to enable the battery to achieve the functions of charging and discharging, and the diaphragm 200 is used to isolate the positive and negative electrodes of the pole piece 100 .

[0047] Reference Figures 3 to 5 As shown, specifically, the pole piece 100 provided in the embodiment of the present application includes a pole piece body 110 and an insulating substrate 120, the insulating substrate 120 includes a substrate body 121 and a limiting portion 122, the pole piece body 110 and the substrate body 121 have the same length direction, the pole piece body 110 is connected to two opposite sides of the substrate body 121, and the polarities of the pole piece body 110 located on two sides of the substrate body 121 are opposite, the limiting portion 122 is located at least one end of the substrate body 121 along its own length direction, the limiting portion 122 is connected to at least one side of the substrate body 121, and extends away from the substrate body 121 along the thickness direction of the substrate body 121, and at least one end of the pole piece body 110 along its own length direction abuts against the limiting portion 122.

[0048] In the present application, the pole piece body 110 is used to react with the electrolyte to generate current, and the insulating substrate 120 is used to insulate and isolate the positive and negative poles of the pole piece body 110, that is, the polarity of one of the pole piece bodies 110 located on both sides of the substrate body 121 is positive, and the polarity of the other is negative. The insulating substrate 120 can prevent the positive pole piece body 110 and the negative pole piece body 110 from directly contacting each other and causing a short circuit.

[0049] During the production process, it is necessary to cold press the pole piece bodies 110 on opposite sides of the substrate body 121 at the same time. In order to make the positive pole piece body 110 and the negative pole piece body 110 reach the required compaction density at the same time, and to avoid overpressure of the negative pole piece body 110, a limiting portion 122 can be provided at one end of the substrate body 121 along its own length direction, and one end of the pole piece body 110 along its own length direction can abut against the limiting portion 122, or limiting portions 122 can be provided at both ends of the substrate body 121 along its own length direction, and both ends of the pole piece body 110 along its own length direction can abut against the limiting portion 122. In this way, the limiting portion 122 can limit the pressing depth of the rolling equipment when compacting the pole piece body 110, so as to avoid overpressure of the pole piece body 110 when a larger pressure is used to compact the pole piece body 110, thereby avoiding the compaction density of the pole piece body 110 not meeting the requirements.

[0050] It should be understood that the limiting portion 122 can be set on one side of the substrate body 121, such as the surface of the substrate body 121 connected to the negative electrode plate body 110, or the limiting portion 122 can be set on two opposite sides of the substrate body 121, that is, the surface of the substrate body 121 connected to the negative electrode plate body 110 and the surface of the substrate body 121 connected to the positive electrode plate body 110 can both be provided with the limiting portion 122.

[0051] The pole piece 100 provided in the embodiment of the present application includes a pole piece body 110 and an insulating substrate 120, wherein the insulating substrate 120 includes a substrate body 121 and a stopper 122. The pole piece body 110 is used to react with the electrolyte to generate current, the substrate body 121 is used to insulate and isolate the pole piece body 110 on two opposite sides of the substrate body 121, and the stopper 122 is used to limit the pressing depth of the rolling device when compacting the pole piece body 110, thereby avoiding the phenomenon of overpressure of the pole piece body 110 when the pressure is large, so that the compaction density of the pole piece 100 is more uniform. Therefore, the pole piece 100 in the embodiment of the present application is not prone to overpressure during cold pressing.

[0052] In a possible implementation, the extension length of the limiting portion 122 along the thickness direction of the substrate body 121 is equal to the thickness of the pole piece body 110 .

[0053] It can be understood that the pole piece body 110 may include a current collector 111 and an active material layer 112, the current collector 111 is connected between the substrate body 121 and the active material layer 112, and the current collector 111 may include a first current collector 1111 and a second current collector 1112, the active material layer 112 may include a first active material layer 1121 and a second active material layer 1122, the first current collector 1111 is connected between the substrate body 121 and the first active material layer 1121, and the second current collector 1112 is connected between the substrate body 121 and the second active material layer 1122.

[0054] That is, the polarity of one of the first current collector 1111 and the second current collector 1112 is positive, and the polarity of the other is negative. Correspondingly, the polarity of one of the first active material layer 1121 and the second active material layer 1122 is positive, and the polarity of the other is negative, and the polarity of the first active material layer 1121 is the same as the polarity of the first current collector 1111, and the polarity of the second active material layer 1122 is the same as the polarity of the second current collector 1112. For example, the first current collector 1111 and the first active material layer 1121 are positive electrodes, and the second current collector 1112 and the second active material layer 1122 are negative electrodes.

[0055] When a limiting portion 122 is provided on one side of the substrate body 121 facing the first current collector 1111, the height of the limiting portion 122 can be equal to the sum of the thicknesses of the first current collector 1111 and the first active material layer 1121. In this way, the rolling device can roll on the surface of the first active material layer 1121 to compact the first active material layer 1121, while preventing the rolling device from pressing too deeply and preventing the first active material layer 1121 from being over-pressed.

[0056] Similarly, when a limiting portion 122 is provided on one side of the substrate body 121 facing the second current collector 1112, the height of the limiting portion 122 can be equal to the sum of the thicknesses of the second current collector 1112 and the second active material layer 1122. In this way, the rolling device can roll on the surface of the second active material layer 1122 to compact the second active material layer 1122, while preventing the rolling device from pressing too deeply, thereby preventing the second active material layer 1122 from being over-pressed.

[0057] In some embodiments, the limiting portion 122 and the substrate body 121 are integrally formed, so that the processing of the limiting portion 122 and the substrate body 121 can be simplified, thereby saving costs.

[0058] Among them, the material of the insulating substrate 120 includes at least one of polypropylene, polyester and polyvinyl chloride, that is, the limiting portion 122 and the substrate body 121 can be integrally injection molded using any one of the materials of polypropylene, polyester and polyvinyl chloride, or, any two of the materials of polypropylene, polyester and polyvinyl chloride can be compounded and then the limiting portion 122 and the substrate body 121 can be simultaneously formed using an integral injection molding process.

[0059] Reference Figure 6 As shown, in a possible implementation, the limiting portion 122 has a groove 1221 on one side facing the pole piece body 110, the pole piece body 110 includes a current collector 111 and an active material layer 112, the current collector 111 is connected between the substrate body 121 and the active material layer 112, and the end of the current collector 111 along its own length direction is inserted into the groove 1221.

[0060] When limiting portions 122 are provided at both ends of the substrate body 121 in the length direction, both ends of the current collector 111 along its own length direction can be inserted into the grooves 1221 of the limiting portions 122. In this way, the grooves 1221 have a limiting effect on the ends of the current collector 111 along its own length direction, so that after the current collector 111 is compounded with the substrate body 121, the current collector 111 can be fixed on the substrate body 121 more stably.

[0061] Reference Figure 4As shown, in a specific implementation, the current collector 111 includes a first current collector 1111 and a second current collector 1112, the active material layer 112 includes a first active material layer 1121 and a second active material layer 1122, the first current collector 1111 is connected between the substrate body 121 and the first active material layer 1121, the second current collector 1112 is connected between the substrate body 121 and the second active material layer 1122, and the material of one of the first current collector 1111 and the second current collector 1112 includes aluminum, and the material of the other includes copper.

[0062] That is to say, one of the first current collector 1111 and the second current collector 1112 can be aluminum foil, and the other can be copper foil. For example, the polarity of the first current collector 1111 is positive, and the first current collector 1111 uses aluminum foil. The polarity of the second current collector 1112 is negative, and the second current collector 1112 uses copper foil. The aluminum foil can better match the active material of the positive electrode, and the copper foil can better match the active material of the negative electrode.

[0063] In some embodiments, when the polarity of the first active material layer 1121 is positive and the polarity of the second active material layer 1122 is negative, because the first active material layer 1121 uses positive electrode materials, the material cost is relatively high and the conductivity is relatively poor, the width of the first active material layer 1121 can be less than or equal to the width of the first current collector 1111, which can reduce the material cost of the first active material layer 1121. The second active material layer 1122 uses negative electrode materials, which have good conductivity, therefore, the width of the second active material layer 1122 can be greater than or equal to the width of the second current collector 1112 to improve the conductivity of the electrode sheet 100.

[0064] It is understandable that in order to allow lithium ions to have sufficient attachment sites on the electrode 100 and thereby prevent lithium deposition on the electrode 100, when the polarity of the first active material layer 1121 is positive and the polarity of the second active material layer 1122 is negative, the width of the first active material layer 1121 may be smaller than the width of the second active material layer 1122. In this way, the active material of the negative electrode can be more than that of the positive electrode, thereby allowing lithium ions to have sufficient space to embed on the negative electrode body 110, thereby preventing lithium deposition on the electrode 100, thereby improving the conductivity and safety performance of the electrode 100. In a specific implementation, the first current collector 1111 can be made to have the same width as the first active material layer 1121, the second current collector 1112 can be made to have the same width as the second active material layer 1122, and the width of the second current collector 1112 and the width of the first current collector 1111 are both smaller than the width of the substrate body 121, thereby increasing the creepage distance between the first current collector 1111 and the second current collector 1112, thereby avoiding a short circuit in the electrode 100.

[0065] In a possible implementation, the first current collector 1111 and the second current collector 1112 are both symmetrically arranged with respect to a midline of the length direction of the substrate body 121 .

[0066] Since the width of the first current collector 1111 is smaller than that of the second current collector 1112, and the width of the second current collector 1112 is smaller than that of the substrate body 121, that is, there is a gap between the edge of the first current collector 1111 in the width direction and the edge of the substrate body 121 in the width direction, and there is also a gap between the edge of the second current collector 1112 in the width direction and the edge of the substrate body 121 in the width direction. In order to make the pole piece 100 have a larger tolerance during subsequent winding, the first current collector 1111 and the second current collector 1112 can be symmetrically arranged relative to the substrate body 121 in the width direction.

[0067] In some embodiments, the current collector 111 is connected to the substrate body 121 by thermal melting, wherein the material of the substrate body 121 includes at least one of polypropylene, polyester and polyvinyl chloride.

[0068] In this way, polypropylene, polyester and polyvinyl chloride can all produce good adhesion after hot melting, and the current collector 111 can be directly bonded to the substrate body 121 without the need to set an additional bonding layer between the current collector 111 and the substrate body 121, thereby simplifying the process of the pole piece 100.

[0069] Reference Figure 3 As shown, in a possible implementation, the pole piece 100 provided in the embodiment of the present application may also include a pole ear 130, and the pole ear 130 and the current collector 111 are integrally formed, which can simplify the connection process between the pole ear 130 and the current collector 111, without the need to use welding to connect the pole ear 130 and the current collector 111.

[0070] Specifically, the electrode tab 130 may include a first electrode tab 131 and a second electrode tab 132, the first electrode tab 131 is connected to the first current collector 1111, the second electrode tab 132 is connected to the second current collector 1112, the first electrode tab 131 and the second electrode tab 132 are located on one side of the length direction of the substrate body 121, and the first electrode tab 131 and the second electrode tab 132 are staggered along the length direction of the substrate body 121.

[0071] The pole ear 130 can be used to lead out the positive and negative electrodes of the pole piece 100. The first pole ear 131 is used to lead out the current of the first current collector 1111. Correspondingly, the second pole ear 132 is used to lead out the current of the second current collector 1112. The first pole ear 131 and the second pole ear 132 are located on opposite sides of the thickness direction of the substrate body 121. The first pole ear 131 and the second pole ear 132 are located on the same side of the length direction of the substrate body 121 and are staggered to avoid the first pole ear 131 and the second pole ear 132 contacting each other after the pole piece 100 is wound, thereby causing a short circuit in the battery.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A pole piece, characterized in that: It includes a pole piece body and an insulating substrate, the insulating substrate includes a substrate body and a limiting portion, the pole piece body and the substrate body have the same length direction, the pole piece body is connected to two opposite sides of the substrate body, and the pole piece bodies located on two sides of the substrate body have opposite polarities, the limiting portion is located at at least one end of the substrate body along its own length direction, the limiting portion is connected to at least one side of the substrate body, and extends away from the substrate body along the thickness direction of the substrate body, and at least one end of the pole piece body along its own length direction abuts against the limiting portion.

2. The pole piece according to claim 1, characterized in that: The extension length of the limiting portion along the thickness direction of the substrate body is equal to the thickness of the pole piece body.

3. The pole piece according to claim 1, characterized in that: The limiting portion and the substrate body are integrally formed.

4. The pole piece according to any one of claims 1 to 3, characterized in that: The limiting portion has a groove on one side facing the pole piece body. The pole piece body includes a current collector and an active material layer. The current collector is connected between the substrate body and the active material layer. The end of the current collector along its own length direction is inserted into the groove.

5. The pole piece according to claim 4, characterized in that: The current collector includes a first current collector and a second current collector, the active material layer includes a first active material layer and a second active material layer, the first current collector is connected between the substrate body and the first active material layer, and the second current collector is connected between the substrate body and the second active material layer.

6. The pole piece according to claim 5, characterized in that: The polarity of the first active material layer is positive, the polarity of the second active material layer is negative, the width of the first active material layer is less than or equal to the width of the first current collector, the width of the second active material layer is greater than or equal to the width of the first current collector, and the width of the first current collector and the width of the second current collector are both less than the width of the substrate body; The width of the first active material layer is smaller than the width of the second active material layer.

7. The pole piece according to claim 6, characterized in that: The first current collector and the second current collector are both symmetrically arranged relative to a midline of the length direction of the substrate body.

8. The pole piece according to claim 4, characterized in that: The current collector is thermally melt-connected to the substrate body.

9. The pole piece according to claim 5, characterized in that: It also includes a pole ear, wherein the pole ear and the current collector are integrally formed; The electrode tab includes a first electrode tab and a second electrode tab, the first electrode tab is connected to the first current collector, the second electrode tab is connected to the second current collector, the first electrode tab and the second electrode tab are located on one side of the length direction of the substrate body, and the first electrode tab and the second electrode tab are staggered along the length direction of the substrate body.

10. A battery, characterized in that: The invention comprises a battery cell, wherein the battery cell comprises a diaphragm and a pole piece according to any one of claims 1 to 9, wherein the diaphragm and the pole piece are stacked.

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