Pole piece, battery cell and battery

Abstract

The utility model discloses a pole piece, which comprises a composite current collector, the composite current collector is provided with a coating area and an empty foil area, the coating area and the empty foil area respectively comprise a first conducting layer, a base material layer and a second conducting layer which are laminated, and the empty foil area is at least divided into a non-turnover area and a turnover area positioned at one end of the non-turnover area, the folding area is folded twice from one end of the non-folding area to form a first folding part and a second folding part connected with the first folding part, and the second folding part extends into a folding space of the first folding part and is at least partially overlapped with the non-folding area; the active material layer is arranged on the first conductive layer of the coating area and / or the second conductive layer of the coating area; and the tabs are respectively connected with the first conductive layer at the second folding part and the second conductive layer at the non-folding area, so that the first conductive layer and the second conductive layer are electrically conducted. The pole piece solves the problem that the upper metal layer and the lower metal layer cannot be conducted simultaneously when the composite current collector is used as an electrode current collector, and the utilization rate of the conducting layer of the composite current collector is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium batteries, and particularly relates to an electrode sheet, a battery cell and a battery. Background Art

[0002] With the continuous development of mobile energy storage technology, the requirements for the reliability and safety of its compatible batteries are more extreme. It is expected that the battery can broaden the usage scenarios and reduce geographical restrictions while ensuring safety. Based on this, the conventional metal foil current collectors used in batteries can no longer meet the above requirements at the same time, and composite current collectors have emerged. They integrate the advantages of metal foils and polymers and can meet the comprehensive performance requirements of batteries.

[0003] The structure of the composite current collector is similar to a "sandwich" structure. The inner layer is a substrate layer made of polymer polymers (such as polymer materials like PP / PET / PI, etc.). Conductive layers (such as Al or Cu) are provided on both surfaces of the substrate layer. On the electrode sheet, the tab is usually arranged on one side of the electrode sheet, and one conductive layer of the composite current collector on the corresponding side is welded to the tab and cooperates with the tab to perform charge and discharge. However, the conductive layer on the other side of the composite current collector is not electrically connected to the tab, resulting in the "idle" of the non-conductive conductive layer on that side, which is not fully utilized, wastes materials and occupies space, leading to a low energy density of the battery cell. Summary of the Utility Model

[0004] The main purpose of the utility model is to propose an electrode sheet, aiming to solve the technical problems that the utilization rate of the conductive layer of the composite current collector in the current electrode sheet is low, which wastes materials and occupies space, resulting in a low energy density of the battery cell.

[0005] To achieve the above purpose, the utility model proposes an electrode sheet, which includes:

[0006] A composite current collector, the composite current collector has a coating area and a blank foil area arranged along its length direction. Both the coating area and the blank foil area include a first conductive layer, a substrate layer and a second conductive layer arranged in a stacked manner. The blank foil area is at least divided into a non-folding area and a folding area located at one end of the non-folding area. The folding area is formed by two folds from one end of the non-folding area to form a first folding part and a second folding part connected to the first folding part. The second folding part extends into the folding space of the first folding part and at least partially overlaps with the non-folding area;

[0007] An active material layer, the active material layer is arranged on the first conductive layer and / or the second conductive layer in the coating area;

[0008] The tab is clamped between the first conductive layer at the second folding portion and the second conductive layer in the non-folding area. The tab is connected to the first conductive layer at the second folding portion and the second conductive layer in the non-folding area respectively, so that the first conductive layer and the second conductive layer are electrically connected.

[0009] In some embodiments, the folding area is located at the end area of the end of the empty foil area away from the coating area.

[0010] In some embodiments, the folding area is located between both ends of the empty foil area and is formed by cutting on the empty foil area.

[0011] In some embodiments, the tab has a welding portion for welding connection with the first conductive layer at the second folding portion and the second conductive layer in the non-folding area;

[0012] The length of the second folding portion is greater than the length of the welding portion, and the length of the second folding portion is less than 1 / 4 of the width of the composite current collector.

[0013] In some embodiments, after cutting the folding area, the empty foil area is formed with a cutting hole, and the cutting hole has a plurality of inner corners, and all of the plurality of inner corners are chamfered.

[0014] In some embodiments, the width of the overlapping part of the second folding portion and the non-folding area is greater than the width of the tab.

[0015] In some embodiments, the tensile value of the welding of the tab and the first conductive layer is greater than the peeling force value of the first conductive layer and the substrate layer; and / or,

[0016] The tensile value of the welding of the tab and the second conductive layer is greater than the peeling force value of the second conductive layer and the substrate layer.

[0017] In some embodiments, the thickness of the tab is greater than or equal to the thickness of the composite current collector; and / or,

[0018] The thicknesses of both the first conductive layer and the second conductive layer are less than or equal to the thickness of the substrate layer.

[0019] The present utility model also provides an electric core, which includes a positive electrode tab, a negative electrode tab and a separator, and the separator is disposed between the positive electrode tab and the negative electrode tab;

[0020] Wherein, at least one of the positive electrode tab and the negative electrode tab adopts the tab as described above.

[0021] The present utility model also provides a battery, which includes a housing and the electric core as described above, and the electric core is disposed in the housing.

[0022] In the current collector of the present utility model, the composite current collector has a coating area and a bare foil area arranged in sequence along its length direction. Both the coating area and the bare foil area include a first conductive layer, a substrate layer, and a second conductive layer arranged in a stacked manner. The active material layer is disposed on the first conductive layer and / or the second conductive layer in the coating area. Among them, the bare foil area is at least divided into a folding area and a non-folding area. By folding the folding area twice from one end of the non-folding area, a first folding portion and a second folding portion connected to the first folding portion are formed. The second folding portion extends into the folding space of the first folding portion and at least partially overlaps with the non-folding area. By connecting the tab to the first conductive layer at the second folding portion and the second conductive layer at the non-folding area, the first conductive layer and the second conductive layer are electrically connected, so that both the first conductive layer and the second conductive layer of the composite current collector cooperate with the tab to perform charge and discharge, solving the problem that the upper and lower metal layers of the composite current collector cannot be simultaneously conducted when it is used as an electrode current collector, improving the utilization rate of the conductive layer of the composite current collector, thereby avoiding waste of materials and occupation of space, and improving the energy density of the battery cell. Description of the Drawings

[0023] Figure 1 It is a schematic structural diagram of the current collector in an embodiment of the present utility model;

[0024] Figure 2 It is a schematic structural diagram of the current collector in another embodiment of the present utility model;

[0025] Figure 3 It is a schematic structural diagram of the current collector in yet another embodiment of the present utility model;

[0026] Explanation of the Reference Numerals in the Drawings:

[0027] Label Name Label Name 100 Composite current collector 200 Active material layer 300 Tab 110 Coated area 120 Empty foil area 101 First conductive layer 102 Substrate layer 103 Second conductive layer 121 Non-folded area 122 Folded area 1221 First folding part 1222 Second folding part 310 Welding part K Cutting hole

[0028] The realization, functional features, and advantages of the object of the present utility model will be further described with reference to the embodiments and the accompanying drawings. Detailed Embodiments

[0029] Next, the solutions in the embodiments of the present utility model will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0030] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present utility model are only used to explain the relative positional relationship, movement conditions, etc. between components in a certain specific posture (as shown in the attached drawings). If this specific posture changes, the directional indications will also change accordingly.

[0031] It should also be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as "connected to" another element, it can be directly connected to the other element or there may be an intermediate element at the same time.

[0032] In addition, the descriptions involving "first", "second", etc. in the present utility model are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" can explicitly or implicitly include at least one of such features. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the fact that those skilled in the art can implement it. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present utility model.

[0033] An embodiment of the present utility model provides a pole piece. Referring to Figure 1 and Figure 2 , the pole piece includes:

[0034] A composite current collector 100, the composite current collector 100 has a coating area 110 and a bare foil area 120 arranged along its length direction. Both the coating area 110 and the bare foil area 120 include a first conductive layer 101, a substrate layer 102, and a second conductive layer 103 arranged in a stacked manner. The bare foil area 120 is at least divided into a non-folding area 121 and a folding area 122 located at one end of the non-folding area 121. The folding area 122 is formed by two folds from one end of the non-folding area 121 to form a first folding portion 1221 and a second folding portion 1222 connected to the first folding portion 1221. The second folding portion 1222 extends into the folding space of the first folding portion 1221 and at least partially overlaps with the non-folding area 121;

[0035] An active material layer 200, the active material layer 200 is disposed on the first conductive layer 101 and / or the second conductive layer 103 of the coating area 110;

[0036] The tab 300 is clamped between the first conductive layer 101 at the second folding part 1222 and the second conductive layer 103 in the non-folding area 121. The tab 300 is respectively connected to the first conductive layer 101 at the second folding part 1222 and the second conductive layer 103 in the non-folding area 121, so that the first conductive layer 101 and the second conductive layer 103 are electrically connected.

[0037] The electrode sheet involved in this embodiment can be a positive electrode sheet or a negative electrode sheet, and there is no limitation in this regard. The electrode sheet is applied to the battery cell, and the electrode sheet, another electrode sheet with the opposite polarity thereto, and a separator, etc. are combined to form a battery cell.

[0038] In this electrode sheet, the composite current collector 100 has a coating area 110 and a bare foil area 120. Taking the length direction of the composite current collector 100 as the reference direction, the coating area 110 and the bare foil area 120 are arranged in sequence, and the bare foil area 120 is located at one end of the coating area 110. Moreover, the composite current collector 100 has a multi-layer structure. Both the coating area 110 and the bare foil area 120 of the composite current collector 100 include a first conductive layer 101, a substrate layer 102, and a second conductive layer 103. The substrate layer 102 is a polymer layer, such as a PE polyethylene polymer layer or a PP polypropylene polymer layer, etc. The first conductive layer 101 and the second conductive layer 103 are metal conductive layers, such as metal layers like an aluminum layer, a copper layer, a nickel layer, etc., or other alloy layers, etc. And the first conductive layer 101 and the second conductive layer 103 can be the same metal or different metals.

[0039] The active material layer 200 is disposed on the coating area 110 of the composite current collector 100. Correspondingly, the bare foil area 120 of the composite current collector 100 is not coated with the active material. Among them, the active material layer 200 can be set in one layer, and this active material layer 200 is coated on the first conductive layer 101 of the coating area 110 or coated on the second conductive layer 103 of the coating area 110; or, the active material layer 200 can be set in two layers, one active material layer 200 is coated on the first conductive layer 101 of the coating area 110, and the other active material layer 200 is coated on the second conductive layer 103 of the coating area 110.

[0040] Among them, such as Figure 1 and Figure 2As shown, the empty foil area 120 is divided into regions, and at least a non-folding area 121 and a folding area 122 are divided. The folding area 122 is located at one end of the non-folding area 121. Optionally, the folding area 122 can be located at one end of the non-folding area 121 away from the coating area 110. In addition to this, the folding area 122 can also be located at one end of the non-folding area 121 close to the coating area 110. Within the area of the empty foil area 120, in addition to the divided non-folding area 121 and folding area 122, other areas can also be included, and there is no limitation on this. The folding area 122 is folded from one end of the non-folding area 121 through two folds to form a first folding portion 1221 and a second folding portion 1222, and the second folding portion 1222 is connected to the first folding portion 1221. Moreover, the second folding portion 1222 extends into the folding space of the first folding portion 1221 and has a superimposed relationship with the non-folding area 121 at least partially. Specifically, the first folding portion 1221 is formed by the first fold of the folding area 122 towards the other end of the non-folding area 121, and the second folding portion 1222 is formed by the second fold of the folding area 122 into the folding space of the first folding portion 1221 on the basis of the already folded first folding portion 1221.

[0041] On this basis, the tab 300 is clamped between the first conductive layer 101 at the second folding portion 1222 and the second conductive layer 103 of the non-folding area 121, and is respectively connected to the first conductive layer 101 at the second folding portion 1222 and the second conductive layer 103 of the non-folding area 121, so that the first conductive layer 101 and the second conductive layer 103 are electrically connected. Both the first conductive layer 101 and the second conductive layer 103 cooperate with the tab 300 to perform charge and discharge, improving the utilization rate of the conductive layers of the composite current collector 100, thereby avoiding waste of materials and occupation of space, and improving the energy density of the battery cell. Optionally, the connection method between the tab 300 and the first conductive layer 101 at the second folding portion 1222 can be a welding connection, and the connection method between the tab 300 and the second conductive layer 103 of the non-folding area 121 can be a welding connection.

[0042] It should be noted that the so-called electrical connection between the first conductive layer 101 and the second conductive layer 103 means that the first conductive layer 101 and the second conductive layer 103 in the coating area 110 and the first conductive layer 101 and the second conductive layer 103 in the empty foil area 120 are all electrically connected.

[0043] There can be various situations for the setting position of the folding area 122 divided in the empty foil area 120. For example:

[0044] In some embodiments, refer to Figure 3, the folding area 122 is located in the end area of the end of the empty foil area 120 away from the coating area 110. By arranging the folding area 122 in the end area of the empty foil area 120, the height of the folding area 122 is equal to the height of the pole piece. Therefore, the folding area 122 can be directly folded from the end area of the empty foil area 120 to form the first folding part 1221 and the second folding part 1222, without the need to perform processing operations such as cutting on the folding area 122 in advance, which saves time and effort. Moreover, the burrs on the end edge of the empty foil area 120 after folding are wrapped in the folding space of the first folding part 1221, realizing hidden setting, which can reduce the risk of the edge burrs piercing the diaphragm and is beneficial to improving the safety of the battery cell.

[0045] In addition to the above setting positions, it can also be that, in some embodiments, referring to Figure 2 , the folding area 122 is located between the two ends of the empty foil area 120 and is formed by cutting on the empty foil area 120. Specifically, when the folding area 122 is located between the two ends of the empty foil area 120, the folding area 122 can be located at the edge position of the empty foil area 120 along the length direction of the composite current collector 100; or, the folding area 122 can be located at a non-edge position of the empty foil area 120, and the non-edge position of the empty foil area 120 can be the middle position of the empty foil area 120, etc. Moreover, in order to realize folding, the folding area 122 is obtained by cutting, and the cutting method can be, for example, knife cutting, laser cutting, etc., which is not limited thereto. Among them, when the folding area 122 is arranged at the edge position of the empty foil area 120, the folding area 122 is cut inward from the edge line of the empty foil area 120.

[0046] In some embodiments, referring to Figure 2 and Figure 3 , the tab 300 has a welding part 310 for welding and connecting with the first conductive layer 101 at the second folding part 1222 and the second conductive layer 103 at the non-folding area 121;

[0047] The length of the second folding part 1222 is greater than the length of the welding part 310 and less than 1 / 4 of the width of the composite current collector 100.

[0048] In this embodiment, the tab 300 extends between the second folding portion 1222 and the non-folding area 121 through its welding portion 310, and is welded to the first conductive layer 101 at the second folding portion 1222 and the second conductive layer 103 at the non-folding area 121. Among them, by setting the length of the second folding portion 1222 to be greater than the length of the welding portion 310, when the welding portion 310 of the tab 300 is clamped between the second folding portion 1222 and the non-folding area 121, in the common length direction, the welding portion 310 of the tab 300 can be completely welded to the second folding portion 1222 and the non-folding area 121, maximizing the welding length of the welding portion 310 of the tab 300, thereby ensuring the welding strength of the tab 300 and enhancing the connection stability between the tab 300 and the second folding portion 1222 and the non-folding area 121.

[0049] Meanwhile, the length of the second folding portion 1222 is set to be less than 1 / 4 of the width of the composite current collector 100. That is, in the width direction of the composite current collector 100, the corresponding limited folding area 122 is cut with a smaller length, thereby preventing the folding area 122 from affecting the structural strength of the composite current collector 100 due to excessive cutting length and preventing the pole piece from breaking.

[0050] In some embodiments, referring to Figure 1 and Figure 2 , after cutting the folding area 122, the empty foil area 120 forms a cutting hole K, and the cutting hole K has a plurality of inner corners, and all the inner corners are chamfered. The cutting hole K penetrates through the empty foil area 120 and has the same contour shape as the folding area 122. For example, the cutting hole K is a square hole with four inner corners, and the four inner corners are respectively distributed at the four corners of the cutting hole K and are all chamfered. Among them, the chamfer can be a rounded corner, etc. By chamfering each inner corner of the cutting hole K, it is beneficial to reduce the stress concentration at the inner corner position of the cutting hole K, and the stress can be better dispersed and balanced.

[0051] In some embodiments, referring to Figure 1 and Figure 2 , the width of the overlapping part of the second folding portion 1222 and the non-folding area 121 is greater than the width of the tab 300. In this embodiment, by setting the width of the overlapping part of the second folding portion 1222 and the non-folding area 121 to be greater than the width of the tab 300, when the tab 300 is clamped between the second folding portion 1222 and the non-folding area 121, in the common width direction, the tab 300 can be completely welded to the second folding portion 1222 and the non-folding area 121, maximizing the welding width of the tab 300, thereby ensuring the welding strength of the tab 300 and enhancing the connection stability between the tab 300 and the second folding portion 1222.

[0052] In some embodiments, the tensile force value of the tab 300 welded to the first conductive layer 101 is greater than the peel force value of the first conductive layer 101 from the substrate layer 102. Herein, the so-called tensile force value of the tab 300 welded to the first conductive layer 101 refers to the maximum tensile force that the tab 300 and the first conductive layer 101 can withstand after welding. When the external tensile force applied to the tab 300 is less than the tensile force value of the tab 300 welded to the first conductive layer 101, the tab 300 will not detach from the first conductive layer 101. When the external tensile force applied to the tab 300 is greater than the tensile force value of the tab 300 welded to the first conductive layer 101, the tab 300 will detach from the first conductive layer 101. The peel force value of the first conductive layer 101 from the substrate layer 102 refers to the force value at which the first conductive layer 101 peels off from the substrate layer 102. When the peeling force applied to the first conductive layer 101 reaches this force value, the first conductive layer 101 will peel off from the substrate layer 102. In this embodiment, by setting the tensile force value of the tab 300 welded to the first conductive layer 101 to be greater than the peel force value of the first conductive layer 101 from the substrate layer 102, when the tab 300 is subjected to an external force, when the external force is large, first, the first conductive layer 101 will peel off from the substrate layer 102, and the tab 300 will not detach from the first conductive layer 101, thus ensuring the welding strength of the tab 300. And / or, the tensile force value of the tab 300 welded to the second conductive layer 103 is greater than the peel force value of the second conductive layer 103 from the substrate layer 102. Herein, the so-called tensile force value of the tab 300 welded to the second conductive layer 103 refers to the maximum tensile force that the tab 300 and the second conductive layer 103 can withstand after welding. When the external tensile force applied to the tab 300 is less than the tensile force value of the tab 300 welded to the second conductive layer 103, the tab 300 will not detach from the second conductive layer 103. When the external tensile force applied to the tab 300 is greater than the tensile force value of the tab 300 welded to the second conductive layer 103, the tab 300 will detach from the second conductive layer 103. The peel force value of the second conductive layer 103 from the substrate layer 102 refers to the force value at which the second conductive layer 103 peels off from the substrate layer 102. When the peeling force applied to the second conductive layer 103 reaches this force value, the second conductive layer 103 will peel off from the substrate layer 102. In this embodiment, by setting the tensile force value of the tab 300 welded to the second conductive layer 103 to be greater than the peel force value of the second conductive layer 103 from the substrate layer 102, when the tab 300 is subjected to an external force, when the external force is large, first, the second conductive layer 103 will peel off from the substrate layer 102, and the tab 300 will not detach from the second conductive layer 103, thus ensuring the welding strength of the tab 300.

[0053] In some embodiments, the thickness of the tab 300 is greater than or equal to the thickness of the composite current collector 100. Specifically, by setting the thickness of the tab 300 to be greater than or less than the thickness of the composite current collector 100, sufficient strength can be ensured during the welding of the electrode tab and the composite current collector 100, thereby improving the welding stability of the tab 300. And / or, in some embodiments, the thicknesses of both the first conductive layer 101 and the second conductive layer 103 are less than or equal to the thickness of the substrate layer 102. Specifically, by setting the thicknesses of both the first conductive layer 101 and the second conductive layer 103 to be less than or equal to the thickness of the substrate layer 102, the thickness of the substrate layer 102 can be ensured to be relatively thick, so that the internal structure of the battery can be better isolated and protected, reducing the occurrence of safety risks such as short circuits and overheating, and effectively improving the overall safety of the battery cell. Moreover, setting a relatively thick substrate layer 102 can reduce the demand for expensive metal materials while ensuring the performance of the battery cell, thereby reducing production costs and improving economic benefits.

[0054] An embodiment of the present utility model further provides a battery cell, which includes a positive electrode tab, a negative electrode tab, and a separator, and the separator is disposed between the positive electrode tab and the negative electrode tab;

[0055] Wherein, at least one of the positive electrode tab and the negative electrode tab adopts the electrode tab described in the foregoing embodiments.

[0056] Specifically, it may be that the positive electrode tab adopts the foregoing electrode tab, or the negative electrode tab adopts the foregoing electrode tab, or both the positive electrode tab and the negative electrode tab adopt the foregoing electrode tab.

[0057] For the specific structure of the electrode tab, reference may be made to the above embodiments. Since this battery cell adopts all the technical solutions of all the above embodiments, it has at least all the technical effects brought by the technical solutions of the above embodiments, which will not be elaborated herein one by one.

[0058] An embodiment of the present utility model further provides a battery, which includes a housing and the battery cell described in the foregoing embodiments, and the battery cell is disposed in the housing. For the specific structure of the battery cell, reference may be made to the above embodiments. Since this battery adopts all the technical solutions of all the above embodiments, it has at least all the technical effects brought by the technical solutions of the above embodiments, which will not be elaborated herein one by one. Among them, the type of the battery may be a lithium battery.

[0059] The above are only partial or preferred embodiments of the present utility model. Whether in terms of text or drawings, the scope of protection of the present utility model cannot be limited thereby. Any equivalent structural transformation made by using the content of the specification and drawings of the present utility model under the overall concept of the present utility model, or any direct / indirect application in other related technical fields is included in the scope of protection of the present utility model.

Claims

1. A pole piece, characterized in that, Comprising: A composite current collector, the composite current collector having a coated area and a bare foil area disposed along its length direction, both the coated area and the bare foil area including a first conductive layer, a substrate layer, and a second conductive layer stacked on top of each other. The bare foil area is at least divided into a non-folded area and a folded area located at one end of the non-folded area. The folded area is formed by folding twice from one end of the non-folded area to form a first folded portion and a second folded portion connected to the first folded portion. The second folded portion extends into the folding space of the first folded portion and at least partially overlaps with the non-folded area. An active material layer, the active material layer being disposed on the first conductive layer and / or the second conductive layer in the coated area. A tab, the tab being clamped between the first conductive layer at the second folded portion and the second conductive layer in the non-folded area. The tab is respectively connected to the first conductive layer at the second folded portion and the second conductive layer in the non-folded area, and electrically conducts between the first conductive layer and the second conductive layer.

2. The pole piece according to claim 1, characterized in that, The folded area is located at the end area of the bare foil area away from the coated area.

3. The pole piece according to claim 1, characterized in that, The folded area is located between the two ends of the bare foil area and is formed by cutting on the bare foil area.

4. The pole piece according to claim 3, wherein The tab has a welding portion for welding and connecting to the first conductive layer at the second folded portion and the second conductive layer in the non-folded area. The length of the second folded portion is greater than the length of the welding portion, and the length of the second folded portion is less than 1 / 4 of the width of the composite current collector.

5. The pole piece according to claim 3, wherein, After cutting the folded area, a cutting hole is formed in the bare foil area. The cutting hole has a plurality of inner corners, and all of the plurality of inner corners are chamfered.

6. The pole piece according to claim 1, characterized in that, The width of the portion where the second folded portion overlaps with the non-folded area is greater than the width of the tab.

7. The electrode tab according to claim 1, characterized in that, The tensile value of the welding of the tab to the first conductive layer is greater than the peel force value of the first conductive layer from the substrate layer; and / or, The tensile value of the welding of the tab to the second conductive layer is greater than the peel force value of the second conductive layer from the substrate layer.

8. The pole piece according to claim 1, characterized in that, The thickness of the tab is greater than or equal to the thickness of the composite current collector; and / or, The thicknesses of both the first conductive layer and the second conductive layer are less than or equal to the thickness of the substrate layer.

9. A battery cell, characterized in that, Comprising a positive electrode tab, a negative electrode tab, and a separator, the separator being disposed between the positive electrode tab and the negative electrode tab. Wherein, at least one of the positive electrode tab and the negative electrode tab is a tab according to any one of claims 1 to 8.

10. A battery, characterized in that, Comprising a housing and a battery cell according to claim 9, the battery cell being disposed in the housing.

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