Pole piece assembly and battery

Abstract

The utility model relates to a pole piece assembly and a battery, and relates to the technical field of batteries, the pole piece assembly comprises a pole piece and a conductive foil, the pole piece comprises a pole piece main body and a pole lug, the pole lug is made of a composite current collector, the pole lug is partially bent to form a bent section and a main body section which are connected with each other, the main body section comprises an overlapping section and a non-overlapping section which are connected with each other, the non-overlapping section is connected with the pole piece main body, and the bending section is connected with the overlapping section; the conductive foil comprises a first connecting section and a second connecting section which are connected with each other, the first connecting section is connected with one side, deviating from the overlapping section, of the bending section, and the second connecting section is connected with the non-overlapping section; wherein the length of the second connecting section is smaller than that of the non-overlapping section. The pole piece assembly and the battery can reduce the waste of the conductive foil, reduce the weight of the pole piece assembly and improve the energy density of the battery.

Description

Technical Field

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

[0002] The middle layer of the composite current collector is made of a polymer material that is not easy to break, and the two sides are made of metal layers. When using the composite current collector to manufacture the pole ear, since the middle polymer structure layer of the composite current collector is not conductive, it is necessary to use conductive foil and achieve the connection of the metal layers on both sides of the composite current collector through a transfer welding process. In the related art, it is usually necessary to weld conductive foils to the metal layers on both sides of the composite current collector respectively. This not only causes waste of conductive foil, but also causes the pole piece formed after transfer welding to be heavier, affecting the energy density of the battery. Utility Model Content

[0003] In order to solve the above technical problems, the embodiments of the present application provide a pole piece assembly and a battery, which can reduce the waste of conductive foil, reduce the weight of the pole piece assembly, and improve the energy density of the battery.

[0004] In a first aspect, a pole piece assembly is provided, comprising:

[0005] A pole piece, comprising a pole piece body and a pole ear, wherein the pole ear is made of a composite current collector, the pole ear is partially bent to form a bent section and a main section connected to each other, the main section comprises an overlapping section and a non-overlapping section connected to the pole piece body, the non-overlapping section is connected to the pole piece body, and the bent section is connected to the overlapping section;

[0006] The conductive foil comprises a first connecting section and a second connecting section connected to each other, wherein the first connecting section is connected to a side of the bent section facing away from the overlapping section, and the second connecting section is connected to the non-overlapping section;

[0007] The length of the second connecting segment is smaller than the length of the non-overlapping segment.

[0008] According to the first aspect of the present application, a conductive adhesive layer is provided between the bending section and the overlapping section.

[0009] According to the first aspect of the present application, the thickness of the conductive adhesive layer is A, and A satisfies: 10 μm≤A≤30 μm.

[0010] According to the first aspect of the present application, the bending angle of the bending section relative to the main section is 180 degrees.

[0011] According to the first aspect of the present application, the length of the connection area between the first connecting segment and the bending segment is L1, the length of the connection area between the second connecting segment and the non-overlapping segment is L2, and L1 and L2 satisfy: 1 / 3≤L1 / L2≤1.

[0012] According to the first aspect of the present application, the area of the connection region between the first connection segment and the bent segment is S1, and the area of the connection region between the second connection segment and the non-overlapping segment is S2. S1 and S2 satisfy: 1 / 3 ≤ S1 / S2 ≤ 1.

[0013] According to the first aspect of the present application, the conductive foil is a copper foil or an aluminum foil.

[0014] According to the first aspect of the present application, the thickness of the copper foil is B, and B satisfies: 4.5 μm ≤ B ≤ 15 μm; or,

[0015] the thickness of the aluminum foil is C, and C satisfies: 8 μm ≤ C ≤ 15 μm.

[0016] According to the first aspect of the present application, the tab includes a support layer and a conductive layer, and the conductive layer is disposed on two surfaces in the thickness direction of the support layer;

[0017] wherein, the thickness of the tab is D, and D satisfies: 4.5 μm ≤ D ≤ 10 μm.

[0018] In a second aspect, there is also provided a battery, including:

[0019] The tab assembly as described in the previous embodiment.

[0020] The tab assembly and the battery provided by the embodiments of the present application can achieve the function of mutual connection on both sides of the tab by bending a part of the tab and connecting a conductive foil on one side of the bent tab. Compared with the solution in the related art where conductive foils need to be welded on both opposite sides of the tab, it can effectively reduce the waste amount of the conductive foil and reduce the overall weight of the tab assembly, which is beneficial to improving the energy density of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] By describing the embodiments of the present application in more detail in conjunction with the drawings, the above and other objects, features, and advantages of the present application will become more obvious. The drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present application and do not constitute a limitation to the present application. In the drawings, the same reference numerals generally represent the same components or steps.

[0022] Figure 1 A cross-sectional view of an unbent tab provided for an exemplary embodiment of the present application.

[0023] Figure 2 A schematic structural diagram of a tab assembly provided for an exemplary embodiment of the present application.

[0024] Figure 3Schematic diagram of the structure of the main electrode sheet before winding provided by an exemplary embodiment of the present application.

[0025] Reference numerals: 10 - electrode sheet assembly; 100 - electrode sheet; 110 - tab; 111 - bent section; 112 - main body section; 1121 - overlapping section; 1122 - non - overlapping section; 113 - conductive adhesive layer; 115 - support layer; 116 - conductive layer; 120 - main body of the electrode sheet; 130 - conductive foil; 131 - first connection section; 132 - second connection section. Detailed implementation manners

[0026] Next, exemplary embodiments of the present application will be described in detail with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. It should be understood that the present application is not limited by the exemplary embodiments described herein.

[0027] Figure 1 Cross - sectional view of the unbent tab provided by an exemplary embodiment of the present application. Figure 2 Schematic diagram of the structure of the electrode sheet assembly provided by an exemplary embodiment of the present application. As Figure 1 and Figure 2 shown, the electrode sheet assembly 10 provided by the embodiment of the present application may include an electrode sheet 100. The electrode sheet 100 may include a main body 120 of the electrode sheet and a tab 110. The main body 120 of the electrode sheet is generally used to connect to the battery cell, and the tab 110 is connected to the main body 120 of the electrode sheet.

[0028] It should be noted that the material of the tab 110 is a composite current collector. Combining Figure 1 , the tab 110 may include a support layer 115 and a conductive layer 116. The conductive layer 116 is disposed on two surfaces in the thickness direction of the support layer 115. The conductive layer 116 (usually made of metal, such as copper, aluminum, etc.) can be used to transfer current, and the support layer 115 (usually made of polymer material, such as PET, PP, etc.) can be used to enhance the overall strength, so that the tab 110 is not easily broken.

[0029] It should be noted that if the thickness of the tab 110 is too large, the overall weight of the electrode sheet assembly 10 may be too heavy, which will affect the energy density of the battery; if the thickness of the tab 110 is too small, the internal resistance of the battery will increase, affecting the output power of the battery. Therefore, it is necessary to limit the thickness of the tab 110 within a certain range. Specifically, as Figure 1 shown, the thickness of the tab 110 is D, and the thickness D satisfies: 4.5μm ≤ D ≤ 10μm. In this way, it is possible to avoid the overall weight of the electrode sheet assembly 10 from being too heavy, and at the same time ensure the output power of the battery.

[0030] In one embodiment, the thickness D can be selected as 4.5μm, 6μm, 10μm, etc.

[0031] As Figure 2 shown, a part of the tab 110 is bent to form a bent section 111 and a main body section 112 that are connected to each other. The main body section 112 includes an overlapping section 1121 and a non-overlapping section 1122 that are connected to each other. The non-overlapping section 1122 is connected to the aforementioned tab body 120, and the overlapping section 1121 is connected to the aforementioned bent section 111. It should be understood that there is an overlapping area between the side of the overlapping section 1121 close to the bent section 111 and the side of the bent section 111 close to the overlapping section 1121, and they can be electrically connected to each other.

[0032] As Figure 2 shown, the tab assembly 10 may further include a conductive foil 130. The conductive foil 130 includes a first connection section 131 and a second connection section 132 that are connected to each other. The first connection section 131 is connected to the side of the bent section 111 facing away from the overlapping section 1121, and the second connection section 132 is connected to the non-overlapping section 1122.

[0033] In one embodiment, the first connection section 131 and the side of the bent section 111 facing away from the overlapping section 1121 are fixedly connected and electrically conducted to each other by means of a transfer weld, and the second connection section 132 and the non-overlapping section 1122 are fixedly connected and electrically conducted to each other by means of a transfer weld.

[0034] It should be noted that the length of the second connection section 132 is less than the length of the non-overlapping section 1122. In this way, it is possible to prevent the second connection section 132 from contacting the tab body 120 and avoid affecting the normal electrical connection between the second connection section 132 and the non-overlapping section 1122.

[0035] It should be understood that the first connection section 131 and the second connection section 132 are electrically connected to each other, the second connection section 132 is electrically connected to the left side of the non-overlapping section 1122 (the left and right sides in this article are based on Figure 2 the shown state as a reference), the first connection section 131 is connected to the left side of the bent section 111, and due to the bending of the tab 110, the left side of the bent section 111 and the right side of the overlapping section 1121 belong to the same conductive layer 116. Therefore, the first connection section 131 can also be electrically connected to the right side of the overlapping section 1121. That is to say, for the tab assembly 10 provided in the embodiment of the present application, by bending a part of the tab 110 and connecting the conductive foil 130 to one side of the bent tab 110, it is possible to connect the conductive layers 116 on both sides of the tab 110 to each other. Compared with the related art in which conductive foils 130 need to be welded on both opposite sides of the tab 110, it can effectively reduce the waste amount of the conductive foil 130 and reduce the overall weight of the tab assembly 10, which is beneficial to improving the energy density of the battery.

[0036] It should be noted that, compared with the solution in the related art where conductive foils 130 need to be welded on both opposite sides of the tab 110, in the embodiment of the present application, the conductive foil 130 is connected to one side of the bent tab 110, making the overall thickness of the tab 110 during the welding process smaller, which can facilitate ultrasonic welding more conveniently.

[0037] It should be noted that, compared with the solution in the related art where conductive foils 130 need to be welded on both opposite sides of the tab 110, in the embodiment of the present application, the conductive foil 130 is connected to one side of the bent tab 110, and only one transfer weld is required (two transfer welds are required in the related art), effectively reducing the risk of the tab 110 being welded through.

[0038] In one embodiment, the conductive foil 130 can be selected from copper foil or aluminum foil.

[0039] It should be understood that if the thickness of the conductive foil 130 is too large, the overall weight of the electrode assembly 10 may be too heavy, which will affect the energy density of the battery; if the thickness of the conductive foil 130 is too small, the internal resistance of the battery will increase, affecting the output power of the battery. Therefore, it is necessary to limit the thickness of the conductive foil 130 within a certain range.

[0040] Specifically, when the conductive foil 130 is copper foil, the thickness of the copper foil is B, and the thickness B satisfies: 4.5 μm ≤ B ≤ 15 μm; when the conductive foil 130 is aluminum foil, the thickness of the aluminum foil is C, and the thickness C satisfies: 8 μm ≤ C ≤ 15 μm. It should be noted that since the electrical conductivity of copper foil is better than that of aluminum foil, when the thickness of the copper foil is less than that of the aluminum foil, the copper foil can still meet the relevant electrical conductivity requirements, and on this basis, the weight can be effectively reduced and the energy density of the battery can be improved.

[0041] In one embodiment, the thickness B of the copper foil can be selected as 4.5 μm, 10 μm, 15 μm, etc.; the thickness C of the aluminum foil can be selected as 8 μm, 9.5 μm, 15 μm, etc.

[0042] As Figure 2 shown, when the tab 110 is bent, there may be a certain gap between the side of the overlapping section 1121 close to the bent section 111 and the side of the bent section 111 close to the overlapping section 1121, which will affect the battery group margin design. Therefore, a conductive adhesive layer 113 is provided between the bent section 111 and the overlapping section 1121, and the conductive adhesive layer 113 can better achieve electrical connection between the side of the overlapping section 1121 close to the bent section 111 and the side of the bent section 111 close to the overlapping section 1121, while reducing the impact on the battery group margin design.

[0043] It should be understood that if the thickness of the conductive adhesive layer 113 is small, it will affect the conduction performance between the side of the overlapping section 1121 close to the bent section 111 and the side of the bent section 111 close to the overlapping section 1121, and the thickness of the conductive adhesive layer 113 should be less than or equal to the gap width between the side of the overlapping section 1121 close to the bent section 111 and the side of the bent section 111 close to the overlapping section 1121. Therefore, it is necessary to limit the thickness of the conductive adhesive layer 113 within a certain range. Specifically, the thickness of the conductive adhesive layer 113 is A, and A satisfies: 10μm ≤ A ≤ 30μm.

[0044] In one embodiment, the thickness A can be selected as 10μm, 15μm, 30μm, etc.

[0045] In one embodiment, the conductive adhesive layer 113 is a thermosetting adhesive. When welding the conductive foil 130, the thermally conductive adhesive layer is cured by heat, which can make the side of the overlapping section 1121 close to the bent section 111 and the side of the bent section 111 close to the overlapping section 1121 better bonded together, effectively improving the conduction performance between the two.

[0046] As Figure 2 shown, the bending angle of the bent section 111 relative to the main body section 112 is 180 degrees. That is to say, the bent section 111 after bending is parallel to the main body section 112. In this way, on the one hand, it can ensure that the overall thickness after bending is small, and on the other hand, it is convenient to fill the aforementioned conductive adhesive layer 113 between the bent section 111 and the main body section 112.

[0047] As Figure 2 shown, the length of the connection area between the first connection section 131 and the bent section 111 is L1, and the length of the connection area between the second connection section 132 and the non-overlapping section 1122 is L2; if L1 / L2 is too large, then the length of the second connection section 132 will be small, and the contact area after welding the second connection section 132 and the non-overlapping area will be small, which will affect the conduction performance between the second connection section 132 and the non-overlapping section 1122; if L1 / L2 is too large, then the length of the first connection section 131 will be small, and the contact area after welding the first connection section 131 and the bent section 111 will be small, which will affect the conduction performance between the first connection section 131 and the bent section 111. Therefore, it is necessary to limit L1 / L2 within a certain range. Specifically, L1 and L2 satisfy: 1 / 3 ≤ L1 / L2 ≤ 1. In this way, it can be ensured that both the first connection section 131 and the second connection section 132 have sufficient lengths, thus effectively ensuring the conduction performance between the first connection section 131 and the bent section 111 and the conduction performance between the second connection section 132 and the non-overlapping section 1122.

[0048] In one embodiment, L1 / L2 can be selected as 1 / 3, 1 / 2, 1, etc.

[0049] As Figure 2 shown, the area of the connection region between the first connection segment 131 and the bent segment 111 is S1, and the area of the connection region between the second connection segment 132 and the non-overlapping segment 1122 is S2. If S1 / S2 is too large, the welding area between the second connection segment 132 and the non-overlapping region will be small, which will affect the conduction performance between the second connection segment 132 and the non-overlapping segment 1122; if S1 / S2 is too large, the welding contact area between the first connection segment 131 and the bent segment 111 will be small, which will affect the conduction performance between the first connection segment 131 and the bent segment 111. Therefore, it is necessary to limit S1 / S2 within a certain range. Specifically, S1 and S2 satisfy: 1 / 3 ≤ S1 / S2 ≤ 1. In this way, it can be ensured that there is a sufficiently large welding area between the first connection segment 131 and the bent segment 111 and between the second connection segment 132 and the non-overlapping region, thereby effectively ensuring the conduction performance between the first connection segment 131 and the bent segment 111 and the conduction performance between the second connection segment 132 and the non-overlapping segment 1122.

[0050] The embodiment of the present application further provides a battery, which includes the electrode piece assembly 10 described in the foregoing embodiment and has all the functions of the electrode piece assembly 10. The beneficial effects of the battery can refer to the beneficial effects of the foregoing electrode piece assembly 10.

[0051] Figure 3 is a schematic structural diagram of the electrode piece body 120 before winding provided by an exemplary embodiment of the present application. As Figure 3 shown, when performing butt welding on the electrode tab 110 and the conductive foil 130, first weld the multi-layer electrode tabs 110 to the conductive foil 130 respectively, then wind the electrode piece body 120, and finally weld all the foils.

[0052] Specifically, first, the electrode piece after rolling is slit. After slitting, the electrode piece is cut into a certain length to facilitate the subsequent production of the battery. Bend a part of the electrode tabs of the cut electrode piece (the structure after bending can refer to the structure described in the foregoing embodiment). After bending, use a butt welding machine to roll weld the electrode tabs (ultrasonic welding, the butt welding head is circular) to weld the conductive foil on the electrode tabs. After roll welding, perform die cutting on the electrode piece assembly (including the electrode piece and the conductive foil). The shape of the electrode piece assembly after die cutting is as Figure 3 shown, and finally wind the electrode piece assembly after die cutting to obtain a winding core.

[0053] It should be noted that after the transfer welding is completed, generally, the tensile strength and the welding residual area of the transferred welding part are tested to determine the welding effect. The specific test process includes: taking a small piece of the pole piece assembly after the transfer welding is completed, clamping the conductive foil with one clip and the pole piece with the other clip, and using a tensile machine to pull it at a speed of 0-50 mm / s to obtain the corresponding tensile strength, and detecting the welding area of the residual conductive foil in the welding area after the tensile test. The tensile strength of the pole piece assembly provided by the embodiment of the present application is ≥0.06 MPa after testing, and the residual area after stretching is ≥50%, indicating that the welding effect is good.

[0054] Furthermore, the relevant performances of the pole piece assembly of the embodiment of the present application (including internal resistance, conductivity, etc.) are compared with the relevant performances of the pole piece structures in the related technologies (including the structure in which the tab is not bent and the conductive foil is welded on one side of the tab and the structure in which the tab is not bent and the conductive foils are welded on the opposite sides of the tab). The specific comparison process is as follows:

[0055] (1). Prepare the electrolyte: Mix ethylene carbonate (EC), dimethyl carbonate (DMC), and diethyl carbonate (DEC) according to a volume ratio of 1:2:1 to obtain a mixed organic solvent, and then dissolve the fully dried lithium salt LiPF6 in the mixed organic solvent at a ratio of 1 mol / L to prepare the electrolyte.

[0056] (2). Prepare the battery: The battery includes a positive electrode sheet, a negative electrode sheet, an electrolyte, a PP separator, etc. Among them, the positive active material of the positive electrode sheet is a ternary material, and the positive active material of the positive electrode sheet is a graphite material. The preparation methods of the positive electrode sheet and the negative electrode sheet are as follows:

[0057] Preparation of the positive electrode sheet: Mix LiNi 0.6 Co 0.2 Mn 0.2 O2 (ternary material), PVDF, and SP according to a mass ratio of 8:1:1 to obtain a mixed material, stir the mixed material evenly in NMP to obtain the active slurry of the corresponding positive electrode sheet, coat the positive slurry on the front and back sides of the positive current collector aluminum foil to obtain a positive homogenized coating, and then dry and press it to obtain the positive electrode sheet.

[0058] Preparation of the negative electrode sheet: Mix graphite, binder, CMC, and conductive agent according to a mass ratio of 8:0.6:0.8:0.6 to obtain a mixed material, stir the mixed material evenly in deionized water to obtain the active slurry of the corresponding negative electrode sheet; coat the negative homogenized slurry on the front and back sides of the negative current collector copper foil to obtain a negative slurry coating, and then dry and press it to obtain the negative electrode sheet.

[0059] (3). Assemble a lithium battery: Wind the negative electrode sheet, the PP separator (wherein, the second modified layer containing the lithium supplement material is adjacent to the positive electrode sheet), and the positive electrode sheet to obtain an electrode core. The electrode core is installed in a battery case, dried, injected with electrolyte, encapsulated, formed, and sorted to obtain a lithium-ion battery.

[0060] The relevant performance data of the battery obtained by using the electrode assembly structure of the embodiment of the present application and the electrode assembly structure in the related technology are shown in Table 1 and Table 2 below:

[0061] Table 1

[0062] Internal resistance / mΩ Energy density Wh / kg Example 1 / 3 ≤ S1 / S2 ≤ 1 4.32 195.4 Comparative example 1 S1 / S2 < 1 / 3 5.37 193.6 Comparative example 2 S1 / S2 > 1 5.28 193.8

[0063] Table 2

[0064]

[0065] It should be noted that when testing the internal resistance of the battery, usually a battery internal resistance tester is used to directly test the internal resistance of the battery to obtain the corresponding resistance value of the battery;

[0066] Energy density test method: Charge the battery of the above embodiment at a constant current of 0.33C until the voltage reaches 4.4V, rest for 5 minutes, charge at a constant voltage of 4.4V until the charge value is less than or equal to 0.05C, rest for 5 minutes, and discharge at 0.33C until the voltage reaches 2.8V to obtain the energy Q. Weigh the battery and record it as m, and calculate the energy density of the battery using the formula Q / m to obtain the corresponding energy density.

[0067] As can be seen from Table 1, when 1 / 3 ≤ S1 / S2 ≤ 1, its internal resistance is smaller, the energy density is higher, and the battery performance is better.

[0068] As can be seen from Table 2, the internal resistance of the battery obtained by using the structure of the embodiment of the present application is not much different from the internal resistance of the batteries obtained by using the other two structures. However, the energy density is significantly higher than that of the first structure (the second structure where the tab is not bent and the conductive foil is welded on one side of the tab); when the energy density of the battery obtained by using the embodiment of the present application is not much different from the energy density of the battery obtained by using the second structure (the tab is not bent and the conductive foil is welded on the opposite sides of the tab), the amount of conductive foil used is less and the weight is lighter.

[0069] The basic principle of the present application has been described above in combination with specific embodiments. However, it should be noted that the advantages, advantages, effects, etc. mentioned in the present application are only examples and not limitations. It cannot be considered that these advantages, advantages, effects, etc. are essential for each embodiment of the present application. In addition, the above disclosed specific details are only for the purpose of illustration and easy understanding, rather than limitations. The above details do not limit the present application to necessarily adopt the above specific details to implement.

[0070] The block diagrams of the devices, apparatuses, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any way. Words such as "comprising," "including," "having," etc. are open-ended terms that mean "including but not limited to" and can be used interchangeably with each other. The words "or" and "and" as used herein refer to the phrase "and / or" and can be used interchangeably with it, unless the context clearly indicates otherwise. The phrase "such as" as used herein refers to the phrase "such as but not limited to" and can be used interchangeably with it.

[0071] It should also be noted that in the devices, equipment, and methods of this application, each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent solutions of this application.

[0072] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

[0073] The above description has been given for purposes of illustration and description. In addition, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions, and sub-combinations thereof.

Claims

1. A pole piece assembly, characterized in that, include: A pole piece (100) comprises a pole piece body (120) and a pole ear (110), wherein the pole ear (110) is made of a composite current collector, and the pole ear (110) is partially bent to form a bent section (111) and a main section (112) connected to each other, wherein the main section (112) comprises an overlapping section (1121) and a non-overlapping section (1122) connected to each other, wherein the non-overlapping section (1122) is connected to the pole piece body (120), and the bent section (111) is connected to the overlapping section (1121); A conductive foil (130) comprising a first connecting section (131) and a second connecting section (132) connected to each other, wherein the first connecting section (131) is connected to a side of the bending section (111) facing away from the overlapping section (1121), and the second connecting section (132) is connected to the non-overlapping section (1122); Wherein, the length of the second connecting segment (132) is smaller than the length of the non-overlapping segment (1122).

2. The pole piece assembly according to claim 1, characterized in that, A conductive adhesive layer (113) is provided between the bending section (111) and the overlapping section (1121).

3. The pole piece assembly according to claim 2, characterized in that, The thickness of the conductive adhesive layer (113) is A, and A satisfies: 10 μm≤A≤30 μm.

4. The pole piece assembly according to any one of claims 1 to 3, characterized in that, The bending angle of the bending section (111) relative to the main section (112) is 180 degrees.

5. The pole piece assembly according to any one of claims 1 to 3, characterized in that, The length of the connection area between the first connection section (131) and the bending section (111) is L1, and the length of the connection area between the second connection section (132) and the non-overlapping section (1122) is L2, and L1 and L2 satisfy: 1 / 3≤L1 / L2≤1.

6. The pole piece assembly according to any one of claims 1 to 3, characterized in that The area of the connection region between the first connection segment (131) and the bending segment (111) is S1, and the area of the connection region between the second connection segment (132) and the non-overlapping segment (1122) is S2, and S1 and S2 satisfy: 1 / 3≤S1 / S2≤1.

7. The pole piece assembly according to any one of claims 1 to 3, characterized in that, The conductive foil (130) is copper foil or aluminum foil.

8. The electrode sheet assembly according to claim 7, wherein, The thickness of the copper foil is B, and B satisfies: 4.5 μm≤B≤15 μm; or, The thickness of the aluminum foil is C, and C satisfies: 8 μm≤C≤15 μm.

9. The pole piece assembly according to any one of claims 1 to 3, characterized in that, The tab (110) comprises a support layer (115) and a conductive layer (116), wherein the conductive layer (116) is arranged on two surfaces of the support layer (115) in a thickness direction; The tab (110) has a thickness D, and D satisfies the following relationship: 4.5 μm≤D≤10 μm.

10. A battery, characterized in that, include: A pole piece assembly as claimed in any one of claims 1 to 9.

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