Pole piece and battery

Abstract

The utility model relates to the technical field of batteries, and provides a pole piece and a battery, the pole piece comprises a pole piece main body and a pole lug, the pole lug is connected with the pole piece main body, the pole lug comprises two large surfaces which are oppositely arranged in the thickness direction of the pole lug, and a lug boss which protrudes from one large surface to the other large surface is formed on the pole lug. A concave part is formed on one side, deviating from the convex direction, of the convex part; the concave part is at least partially filled with the reinforcing part, and the shore hardness of the reinforcing part ranges from 10 HA to 90 HA. The anti-folding capability of the tab is relatively strong.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a pole piece and a battery. Background Art

[0002] In the related technology, during the transportation of the electrode and the high-speed production of the battery cell, the pole ear will be folded due to various factors such as internal stress, inertia, bumps, wind disturbance, etc. The higher the pole ear is, the greater the chance of folding. Once the pole ear is folded, it will cause overcurrent, self-discharge and other effects on the battery performance. In serious cases, it may even cause thermal runaway of the battery.

[0003] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Utility Model Content

[0004] The utility model provides a pole piece, which can solve the technical problem that a pole ear is easy to fold.

[0005] According to one aspect of the present disclosure, a pole piece comprises:

[0006] Pole body;

[0007] The pole ear is connected to the pole piece body, and the pole ear includes two large surfaces arranged opposite to each other in the thickness direction thereof, and a protrusion protruding from one large surface to the other large surface is formed on the pole ear, and a concave portion is formed on the side of the protrusion away from the protrusion direction thereof;

[0008] The reinforcement part is at least partially filled in the recessed part, and the Shore hardness of the reinforcement part is 10HA-90HA.

[0009] The utility model forms a convex part on the large surface of the pole ear, and fills a reinforcing part in the concave part on the back of the convex part. On the one hand, the convex part can increase the anti-folding ability of the pole ear; on the other hand, the reinforcing part can also further increase the anti-folding ability of the pole ear.

[0010] According to one aspect of the present disclosure, the utility model also provides a battery, which includes the above-mentioned pole piece.

[0011] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to better understand the present disclosure, reference may be made to the embodiments shown in the following drawings. The components in the drawings are not necessarily to scale, and related elements may be omitted in order to emphasize and clearly illustrate the technical features of the present disclosure. In addition, related elements or components may have different arrangements as known in the art. In addition, in the drawings, the same reference numerals represent the same or similar components in each drawing.

[0013] in:

[0014] Figure 1 A top view of an exemplary embodiment of a pole piece disclosed herein;

[0015] Figure 2 for Figure 1 A cross-sectional view of the pole piece along the dotted line AA;

[0016] Figure 3 is a cross-sectional view of another exemplary embodiment of a pole piece disclosed in the present invention;

[0017] Figure 4 It is a top view of another exemplary embodiment of a pole piece disclosed in the present invention.

[0018] Description of reference numerals:

[0019] 1. Pole piece body; 11. Current collector; 12. Active material; 2. Pole ear; 201. Root; 202. Top; 203. First side; 204. Second side; 3. Raised portion; 4. Recessed portion; 5. Reinforced portion; 61. Welding area; 62. Non-welding area; 21. Large surface; 22. Large surface. DETAILED DESCRIPTION

[0020] The following will be combined with the accompanying drawings in the exemplary embodiments of the present disclosure to clearly and completely describe the technical solutions in the exemplary embodiments of the present disclosure. The exemplary embodiments described herein are only for illustrative purposes and are not intended to limit the scope of protection of the present disclosure. Therefore, it should be understood that various modifications and changes can be made to the exemplary embodiments without departing from the scope of protection of the present disclosure.

[0021] In the description of the present disclosure, unless otherwise clearly specified and limited, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance; the term "plurality" refers to two or more; the term "and / or" includes any and all combinations of one or more associated listed items. In particular, reference to "the / the" object or "an" object is also intended to indicate one of a possible plurality of such objects.

[0022] Unless otherwise specified or explained, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, an integral connection, an electrical connection, or a signal connection; "connection" can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in this disclosure can be understood according to specific circumstances.

[0023] Further, in the description of the present disclosure, it should be understood that the directional words such as "upper", "lower", "inner", "outer" and the like described in the exemplary embodiments of the present disclosure are described at the angles shown in the accompanying drawings and should not be understood as limitations on the exemplary embodiments of the present disclosure. It should also be understood that, in the context, when it is mentioned that an element or feature is connected to one or more "upper", "lower", or "inner", "outer" of another element, it can not only be directly connected to the "upper", "lower", "inner", "outer" of another element or elements, but can also be indirectly connected to the "upper", "lower", "inner", "outer" of another element or elements through an intermediate element.

[0024] like Figure 1 , 2 As shown, Figure 1 is a top view of an exemplary embodiment of a pole piece disclosed in the present invention, Figure 2 for Figure 1 The cross-sectional view of the pole piece along the dotted line AA is shown. The pole piece includes: a pole piece body 1, a pole ear 2, and a reinforcement part 5. The pole ear 2 is connected to the pole piece body 1, and the pole ear 2 includes two large surfaces 21 and 22 arranged opposite to each other in the thickness direction thereof. A protrusion 3 protruding from one large surface to the other large surface is formed on the pole ear 2, and a concave part 4 is formed on the side of the protrusion 3 away from the protrusion direction thereof; the reinforcement part 5 is at least partially filled in the concave part 4, and the Shore hardness of the reinforcement part 5 is 10HA-90HA.

[0025] In this exemplary embodiment, a convex portion is formed on the large surface of the tab, and a reinforcing portion is filled in the concave portion on the back of the convex portion. On the one hand, the convex portion can increase the tab's anti-folding ability; on the other hand, the reinforcing portion can further increase the tab's anti-folding ability.

[0026] In the present exemplary embodiment, the Shore hardness of the reinforcement portion 5 may be equal to 10HA, 20HA, 30HA, 40HA, 50HA, 60HA, 70HA, 80HA, 90HA, or the like.

[0027] In this exemplary embodiment, Figure 1 , 2As shown, in the depth direction of the recessed portion 4, the reinforcing portion 5 may not fill up the recessed portion 4. It should be understood that in other exemplary embodiments, in the depth direction of the recessed portion 4, the reinforcing portion 5 may also fill up at least part of the recessed portion 4, and even part of the reinforcing portion may overflow the recessed portion 4.

[0028] In this exemplary embodiment, Figure 1 , 2 As shown, the electrode sheet may also include a current collector 11, a portion of the current collector 11 is coated with an active material 12, and the portion of the current collector coated with the active material 12 and the active material 12 form the electrode sheet body 1. Part of the current collector 11 forms a pole ear 2. For example, the positive electrode sheet includes a positive electrode collector and a positive electrode active material layer located on at least one side of the positive electrode collector, and the negative electrode sheet may include a negative electrode collector and a negative electrode active material layer located on at least one side of the negative electrode collector. For example, the positive electrode active material of the lithium-ion battery may be lithium cobalt oxide, lithium iron phosphate, etc., and the positive electrode collector may be aluminum foil. The negative electrode active material may be graphite, etc., and the negative electrode collector may be copper foil. During charging, lithium ions are separated from the positive electrode active material, move to the negative electrode active material through the electrolyte, and the lithium ions are embedded in the interlayer gaps of the carbon material to complete the charging process of the battery. During discharge, lithium ions are separated from the negative electrode active material, move to the positive electrode active material through the electrolyte, and complete the discharge process of the battery.

[0029] In this exemplary embodiment, Figure 1 , 2 As shown, the tab 2 may include: a welding area 61 and a non-welding area 62; at least part of the protrusion 3 is located in the non-welding area 62, and at least part of the recessed part 4 located in the non-welding area 62 is filled with a reinforcing part 5. This arrangement can ensure that the reinforcing part 5 does not affect the welding between tabs or the welding between tabs and other structures.

[0030] In the present exemplary embodiment, the ratio of the area of ​​the welding area 61 to the area of ​​the pole lug 2 is 1%-40%, for example, the ratio of the area of ​​the welding area 61 to the area of ​​the pole lug 2 can be equal to 1%, 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40%, etc. The Shore hardness of the reinforcement 5 is 20HA-80HA, for example, the Shore hardness of the reinforcement 5 can be equal to 20HA, 30HA, 40HA, 50HA, 60HA, 70HA, 80HA, etc. In this exemplary embodiment, the hardness of the reinforcement part is further limited according to the limitation of the ratio of the welding area area to the lug area. When the welding area area is large, the area of ​​the reinforcement part can be set to be small, and the hardness requirement of the reinforcement part is higher, and the lower limit of the hardness increases; on the contrary, when the welding area area is small, the hardness requirement of the reinforcement part can be lower, and its upper limit decreases. In this exemplary embodiment, the area of ​​the lug 2 is the area of ​​its largest side, and the welding area 61 and the non-welding area 62 are divided on the largest side of the lug.

[0031] In this exemplary embodiment, Figure 1 , 2 As shown, the pole lug 2 includes a root 201 close to the pole piece body 1 and a top 202 away from the pole piece body 1. The pole lug 2 also includes a first side 203 and a second side 204 opposite to each other in the width direction X thereof. The distribution direction of the root 201 and the top 202 of the pole lug 2 is perpendicular to the width direction X of the pole lug 2. The pole lug 2 includes a first region close to its root 201 (i.e., a region whose size from the root 201 is smaller than that from the top 202), a second region close to its top 202 (i.e., a region whose size from the top 202 is smaller than that from the root 201), a third region close to its first side 203 (i.e., a region whose size from the first side 203 is smaller than that from the second side 204), and a fourth region close to its second side 204 (i.e., a region whose size from the second side 204 is smaller than that from the first side 203).

[0032] In this exemplary embodiment, Figure 1 , 2 As shown, the protrusion 3 can be arranged in the second area. The position near the top of the tab 2 is very easy to be folded. In this exemplary embodiment, the protrusion 3 is arranged in the second area, so that the tab folding problem can be improved to a large extent.

[0033] The position near the root of the pole lug 2 is prone to tearing. Other exemplary embodiments may also arrange the protrusion 3 in the first area, thereby greatly improving the problem of the pole lug tearing.

[0034] In addition, in other exemplary embodiments, the protrusion 3 may also be arranged in one or more of the first region, the second region, the third region, and the fourth region, and the reinforcing portion 5 is arranged in the recessed portion 4 corresponding to the protrusion 3. The protrusion 3 and the recessed portion located on the side away from the protruding direction thereof are arranged opposite to each other.

[0035] In this exemplary embodiment, the welding area 61 can be located near the center of the tab, and the first area, the second area, the third area, and the fourth area are all non-welding areas. In this exemplary embodiment, the protrusion 3 is arranged in one or more areas of the first area, the second area, the third area, and the fourth area, so that the reinforcement part can be easily filled in the protrusion 3.

[0036] In this exemplary embodiment, Figure 1 , 2 As shown, the distance h between the root 201 and the top 202 of the tab 2 is 30 mm-70 mm. For example, h can be equal to 30 mm, 31 mm, 32 mm, 33 mm, 34 mm, 35 mm, 36 mm, 37 mm, 38 mm, 39 mm, 40 mm, 41 mm, 42 mm, 43 mm, 44 mm, 45 mm, 46 mm, 47 mm, 48 mm, 49 mm, 50 mm, 51 mm, 52 mm, 53 mm, 54 mm, 55 mm, 56 mm, 57 mm, 58 mm, 59 mm, 60 mm, 61 mm, 62 mm, 63 mm, 64 mm, 65 mm, 66 mm, 67 mm, 68 mm, 69 mm, 70 mm, etc. In this exemplary embodiment, in order to meet the needs of fast charging of the battery, the distance h between the root 201 and the top 202 of the pole lug 2 is relatively large. The larger h is, the easier it is for the pole lug to fold. The solution provided in this exemplary embodiment can better solve the folding problem of the pole lug 2.

[0037] In this exemplary embodiment, Figure 1 , 2As shown, the maximum dimension s of the protrusion 3 in the thickness direction of the tab 2 is 10 μm to 500 μm. For example, s may be equal to 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, 210 μm, 220 μm, 230 μm, 240 μm, 250 μm, 260 μm, 270 μm, 280 μm, 290 μm, 300 μm, 310 μm, 320 μm, 330 μm, 340 μm, 350 μm, 360 μm, 370 μm, 380 μm, 390 μm, 400 μm, 410 μm, 420 μm, 430 μm, 440 μm, 450 μm, 460 μm, 470 μm, 480 μm, 490 μm, 500 μm, 510 μm, 520 μm, 530 μm, 540 μm, 550 μm, 560 μm, 570 μm, 580 μm, 590 μm, 600 μm, 610 μm, 620 μm, 630 μm, 640 μm, 650 μm, 660 μm, 670 μm, 680 60μm, 270μm, 280μm, 290μm, 300μm, 310μm, 320μm, 330μm, 340μm, 350μm, 360μm, 370μm, 380μm, 390μm, 400μm, 410μm, 420μm, 430μm, 440μm, 450μm, 460μm, 470μm, 480μm, 490μm, 500μm, etc. The maximum dimension s of the protrusion 3 in the thickness direction of the pole ear 2 is too small, and the reinforcing effect of the protrusion 3 on the pole ear 2 is weak; the maximum dimension s of the protrusion 3 in the thickness direction of the pole ear 2 is too large, and the pole ear 2 is not easy to stack and weld. In this exemplary embodiment, s is set to a suitable size, which can not only ensure the strength of the pole ear 2, but also facilitate stacking and welding.

[0038] In this exemplary embodiment, the reinforcing part may include a binder. The reinforcing part may be a mixed material of one or more of polypropylene, polybutylene, resin (ethylene and vinyl acetate), polyamide (PA), polyester (PES), polyethylene (LOPE and HDPE), polyesteramide (PEA) and one or more of paraffin wax, microcrystalline wax, and synthetic wax (PE or PP).

[0039] In this exemplary embodiment, Figure 1 , 2 As shown, the raised portion 3 extends in a direction parallel to the large surface of the tab 2, and the cross section of the raised portion 3 perpendicular to its extension direction is arc-shaped. On the one hand, the raised portion 3 with an arc-shaped cross section can fully disperse the internal stress of the tab to the reinforcement portion, thereby greatly reducing the risk of tab folding; on the other hand, this arrangement can facilitate the reinforcement portion, which is a fluid before solidification, to quickly flow and fill into the recessed portion 4.

[0040] In this exemplary embodiment, Figure 1 , 2 As shown, the thickness of the current collector 11 is 5 μm-30 μm, for example, the thickness of the current collector 11 can be 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, etc. The protrusion 3 is formed on a single large surface of the tab 2. When the thickness of the current collector 11 is large, the tab 2 only needs to form a protrusion 3 on a single large surface to achieve the anti-folding requirement.

[0041] In this exemplary embodiment, Figure 3 As shown, it is a cross-sectional view of another exemplary embodiment of the pole piece of the present disclosure. The thickness of the current collector 11 is 2-20 μm. For example, the thickness of the current collector 11 can be 2 μm, 5 μm, 10 μm, 15 μm, 20 μm, etc. A protrusion 3 is formed on both large surfaces of the pole lug 2, and the protrusions 3 on the two large surfaces of the pole lug 2 are staggered. When the thickness of the current collector 11 is thin, the strength of the current collector 11 itself is low. In this exemplary embodiment, a protrusion 3 is formed on both large surfaces of the pole lug 2. This arrangement can greatly increase the strength of the pole lug through the protrusions 3 on both sides of the pole lug.

[0042] In this exemplary embodiment, Figure 1 , 2 As shown, the protrusion 3 is in a strip shape on the pole lug 2. It should be understood that in other exemplary embodiments, the protrusion 3 can also be in other shapes on the pole lug 2. For example, Figure 4 , which is a top view of another exemplary embodiment of the pole piece of the present disclosure. The protrusion 3 on the pole ear 2 can also be in a diamond shape. In addition, in other exemplary embodiments, the protrusion 3 on the pole ear 2 can also be in a circular shape, an "M" shape, etc.

[0043] In this exemplary embodiment, the electrode sheet may be a negative electrode sheet. The current collector in the negative electrode sheet is a copper foil, which has a small thickness and low strength. Accordingly, the tab in the negative electrode sheet is more likely to fold. In this exemplary embodiment, the strength of the tab can be increased by providing a protrusion and a reinforcement.

[0044] In other exemplary embodiments, the electrode sheet may also be a positive electrode sheet.

[0045] This exemplary embodiment also provides a battery, which may include the above-mentioned pole piece. The above-mentioned pole piece may be wound or stacked to form a battery cell in the battery, and the battery cell may include a plurality of the above-mentioned pole tabs, and the plurality of pole tabs may be stacked and welded to form a pole tab portion of the battery cell.

[0046] In this exemplary embodiment, the battery includes a first pole piece and a second pole piece, the thickness of the first pole piece is less than the thickness of the second pole piece, and the first pole piece forms a pole piece, that is, the first pole piece has the structural features of the above-mentioned pole piece.

[0047] It should be noted that a battery includes a cell and an electrolyte, and a battery is the smallest unit capable of performing electrochemical reactions such as charge / discharge. A cell refers to a unit formed by winding or laminating a stacked portion, wherein the stacked portion includes a first pole sheet, a separator, and a second pole sheet. When the first pole sheet is a positive pole sheet, the second pole sheet is a negative pole sheet. The polarities of the first pole sheet and the second pole sheet can be interchanged. The first pole sheet and the second pole sheet are coated with an active material.

[0048] In this exemplary embodiment, the battery may be a lithium-ion battery. It should be understood that in other exemplary embodiments, the battery may also be a nickel-cadmium battery, a nickel-metal hydride battery, a lithium polymer battery, a sodium-ion battery, a solid-state battery, etc.

[0049] In other exemplary embodiments, the battery may be a square battery, that is, the battery may be a quadrangular prism-type battery. The quadrangular prism-type battery mainly refers to a battery having a prism-shaped appearance, but does not strictly limit whether each side of the prism must be a straight line in the strict sense, and the corners between the sides are not necessarily right angles, and may be arc transitions.

[0050] The battery can be a laminated battery, which is not only convenient to group, but also can be processed to obtain a longer battery. Specifically, the battery cell is a laminated battery cell, which has a first pole piece stacked on top of each other, a second pole piece with electrical properties opposite to the first pole piece, and a diaphragm sheet arranged between the first pole piece and the second pole piece, so that multiple pairs of first pole pieces and second pole pieces are stacked to form a laminated battery cell.

[0051] Alternatively, the battery may be a wound battery, that is, a first pole sheet, a second pole sheet with electrical properties opposite to the first pole sheet, and a diaphragm sheet arranged between the first pole sheet and the second pole sheet are wound to obtain a wound battery cell.

[0052] The exemplary embodiment further provides a battery device, which is a battery module or a battery pack.

[0053] The battery module includes a plurality of batteries, which may be square batteries, and the battery module may further include end plates and side plates, which are used to fix the plurality of batteries. The batteries may be cylindrical batteries, which may be arranged on a support plate to form a battery module.

[0054] The battery pack includes a plurality of batteries and a box body, and the box body is used to fix the plurality of batteries.

[0055] It should be noted that the battery pack includes a battery, and the battery may be multiple, and the multiple batteries are arranged in the box. Among them, the multiple batteries can be installed in the box after forming a battery module. Alternatively, the multiple batteries can be directly arranged in the box, that is, there is no need to group the multiple batteries, and the box is used to fix the multiple batteries.

[0056] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing what is disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary technical means in the art that are not disclosed in the present disclosure. The specification and embodiments are to be considered merely as exemplary, and the true scope and spirit of the present disclosure are indicated by the claims.

[0057] The drawings in the present disclosure only relate to the structures involved in the present disclosure, and other structures may refer to the usual design. In the absence of conflict, the embodiments of the present disclosure and the features in the embodiments may be combined with each other to obtain new embodiments. It should be understood by those of ordinary skill in the art that the technical solutions of the present disclosure may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present disclosure, and should be included in the scope of the claims of the present disclosure.

[0058] It should be understood that the present disclosure is not limited to the exact structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A pole piece, characterized in that: The pole piece comprises: Pole piece body (1); A pole ear (2) connected to the pole piece body (1), the pole ear (2) comprising two large faces arranged opposite to each other in the thickness direction thereof, a protrusion (3) protruding from one large face to the other large face formed on the pole ear (2), and a recess (4) formed on the side of the protrusion (3) away from the protrusion direction thereof; The reinforcing portion (5) is at least partially filled in the recessed portion (4), and the Shore hardness of the reinforcing portion (5) is 10HA-90HA.

2. The pole piece according to claim 1, characterized in that: The electrode tab (2) comprises: a welding area (61) and a non-welding area (62); At least part of the raised portion (3) is located in the non-welding area (62), and at least part of the recessed portion (4) located in the non-welding area (62) is filled with the reinforcing portion (5).

3. The pole piece according to claim 2, characterized in that: The ratio of the area of ​​the welding zone (61) to the area of ​​the pole ear (2) is 1%-40%, and the Shore hardness of the reinforcement part (5) is 20HA-80HA.

4. The pole piece according to claim 1, characterized in that: The pole ear (2) comprises a root portion close to the pole piece body (1) and a top portion away from the pole piece body (1); The pole lug (2) further comprises a first side edge and a second side edge which are opposite to each other in the width direction thereof, and the distribution direction of the root and the top of the pole lug (2) is perpendicular to the width direction of the pole lug (2); The pole ear (2) comprises a first region close to its root, a second region close to its top, a third region close to its first side edge, and a fourth region close to its second side edge; The raised portion is arranged in one or more of the first area, the second area, the third area and the fourth area, and the reinforcing portion (5) is arranged in the recessed portion (4) corresponding to the raised portion (3).

5. The pole piece according to claim 1, characterized in that: The pole ear (2) comprises a root portion close to the pole piece body (1) and a top portion away from the pole piece body (1), and the distance between the root portion and the top portion of the pole ear (2) is 30 mm to 70 mm.

6. The pole piece according to claim 1, characterized in that: The maximum dimension of the protrusion (3) in the thickness direction of the electrode tab (2) is 10 μm to 500 μm.

7. The pole piece according to claim 1, characterized in that: The protrusion (3) extends in a direction parallel to the large surface of the pole lug (2), and the cross section of the protrusion (3) perpendicular to its extension direction is arc-shaped.

8. The pole piece according to any one of claims 1 to 7, characterized in that: The reinforcement part (5) comprises an adhesive.

9. The pole piece according to any one of claims 1 to 7, characterized in that: The pole piece further comprises: a current collector (11), the pole lug (2) is formed by a portion of the current collector (11), the thickness of the current collector (11) is 5 μm-30 μm, and the protrusion (3) is formed on a single large surface of the pole lug (2).

10. The pole piece according to any one of claims 1 to 7, characterized in that: The pole piece further comprises: a current collector (11), the pole ear (2) is formed by a part of the current collector (11), and the thickness of the current collector (11) is 2-20 μm; The protrusions (3) are formed on both large surfaces of the pole lug (2), and the protrusions (3) on the two large surfaces of the pole lug (2) are staggered.

11. A battery, characterized in that: The battery comprises the pole piece according to any one of claims 1 to 10.

12. The battery according to claim 11, characterized in that The battery includes a first pole piece and a second pole piece, the thickness of the first pole piece is smaller than the thickness of the second pole piece, and the first pole piece forms the pole piece.

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