Pole piece, battery cell and battery

Abstract

The utility model discloses a pole piece, a battery cell and a battery, and belongs to the technical field of batteries. The pole piece comprises a composite current collector and a foil; wherein the composite current collector is provided with a first region and a second region, active material layers are respectively arranged on two opposite sides of the first region on the composite current collector, and the second region is not provided with the active material layer; one end of the foil is welded to the second area to form a welding area, the other end of the foil extends out of the second area to form a tab, and the width of the welding area is larger than that of the tab in the first direction. According to the pole piece, the needling capability of the battery cell can be improved by adopting the composite current collector; and the conduction area of current can be increased by increasing the width of the welding region, so that the internal resistance of the battery cell can be reduced, and the problem that the internal resistance of the battery cell is relatively large due to the adoption of a composite current collector in a pole piece is solved.

Description

Technical Field

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

[0002] The current collector is one of the indispensable components of the electrode in the lithium-ion battery cell. The current collector can not only carry the active substances, but also collect and output the current generated by the active substances, which is beneficial to reduce the internal resistance of the lithium-ion battery cell and improve the coulombic efficiency, cycle stability and rate performance of the lithium-ion battery cell.

[0003] The composite current collector is a composite material that uses a plastic film as a base film and deposits copper / aluminum molecules on both sides through processes such as vacuum coating. Compared with traditional current collectors, composite current collectors have the characteristics of high safety, high energy density, low cost, long life and strong compatibility, which can greatly improve the puncture ability of lithium-ion batteries; however, due to the substrate problem in the composite current collector, there is a large internal resistance in the lithium-ion battery.

[0004] In view of the above problems, electrodes, battery cells and batteries are urgently needed to solve the above problems. Utility Model Content

[0005] The purpose of the utility model is to provide a pole piece, a battery cell and a battery, which can improve the acupuncture ability of the battery cell and solve the problem of large internal resistance of the battery cell caused by using a composite current collector in the pole piece.

[0006] To achieve this purpose, the utility model adopts the following technical solutions:

[0007] Pole piece, including:

[0008] A composite current collector, the composite current collector having a first region and a second region, active material layers are respectively disposed on opposite sides of the first region of the composite current collector, and the active material layer is not disposed in the second region;

[0009] A foil material, one end of which is welded to the second region to form a welding zone, and the other end of which extends out of the second region to form a pole ear, wherein in a first direction, the width of the welding zone is greater than the width of the pole ear, and the first direction is parallel to the width direction of the composite current collector.

[0010] As an optional solution, a transition chamfer is formed at the connection between the welding area and the pole lug.

[0011] As an optional solution, in the second direction, the weld print height of the electrode tab is higher than the weld print height of the welding zone, and the second direction is parallel to the length direction of the composite current collector.

[0012] As an optional solution, the foils are respectively welded on two opposite sides of the composite current collector located in the second region, the two foils are electrically connected through the composite current collector, and one of the foils with a longer length forms the electrode tab.

[0013] A battery cell comprises a diaphragm, a positive electrode sheet and a negative electrode sheet, wherein the diaphragm is arranged between the positive electrode sheet and the negative electrode sheet, and the positive electrode sheet and / or the negative electrode sheet are the electrode sheets as described above; the electrode tabs comprise a positive electrode tab and a negative electrode tab, wherein the positive electrode tab is arranged on the positive electrode sheet, and the negative electrode tab is arranged on the negative electrode sheet.

[0014] As an optional solution, the positive electrode ear and the negative electrode ear are located on the same side, the positive electrode sheet is the electrode sheet, and the interval between the edge of the welding area and the negative electrode ear is 4mm-6mm; or the negative electrode sheet is the electrode sheet, and the interval between the edge of the welding area and the positive electrode ear is 4mm-6mm.

[0015] As an optional solution, the positive electrode ear and the negative electrode ear are located on the same side, the positive electrode sheet and the negative electrode sheet are respectively the electrode sheets, and the interval between the welding area on the positive electrode sheet and the welding area on the negative electrode sheet is 4mm-6mm.

[0016] As an optional scheme, the positive electrode ear and the negative electrode ear are located on different sides, the positive electrode sheet and / or the negative electrode sheet are the electrode sheets, and in the first direction, the width of the welding area on the positive electrode sheet and / or the width of the welding area on the negative electrode sheet is equal to the side length of the composite current collector on which the foil is welded.

[0017] A battery comprises the battery cell as described above, and the battery further comprises a shell and a top cover, wherein the battery cell is arranged in the shell, the top cover is arranged on the open end of the shell, and the pole ear on the battery cell is used to be electrically connected to the pole on the top cover.

[0018] As an optional solution, the battery cell is a laminated battery cell, the top cover is provided with an abutment portion, and in the first direction, there is an avoidance gap between the edge of one side of the foil provided on the composite current collector and the edge of the welding area so that the abutment portion abuts against the composite current collector.

[0019] The beneficial effects of the utility model are:

[0020] By welding one end of the foil to the second area on the composite current collector where the active material layer is not provided, the other end of the foil extends out of the second area to form a pole ear, so as to form a complete pole piece structure, and the use of the composite current collector can improve the puncture ability of the battery cell; and in the first direction, the width of the welding area between the foil and the composite current collector is greater than the width of the pole ear, and the current conduction area can be increased by increasing the width of the welding area, thereby reducing the internal resistance of the battery cell, thereby solving the problem of large internal resistance of the battery cell caused by the use of the composite current collector in the pole piece. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the structure of the pole piece provided by the utility model before cutting. Figure 1 ;

[0022] Figure 2 This is a schematic diagram of the structure of the pole piece provided by the utility model before cutting. Figure 2 ;

[0023] Figure 3 It is a schematic diagram of the structure of the pole piece (laminated battery core) provided by the utility model after cutting;

[0024] Figure 4 It is a structural schematic diagram of the laminated battery core provided by the utility model;

[0025] Figure 5 It is a schematic diagram of the structure of the pole piece (wound battery core) provided by the utility model after cutting;

[0026] Figure 6 It is a structural schematic diagram of the wound battery core provided by the utility model;

[0027] Figure 7 It is a schematic diagram of the exploded structure of the battery provided by the utility model.

[0028] Description of reference numerals:

[0029] 1-pole piece; 11-composite current collector; 12-active material layer; 131-foil; 132-pole ear; 1321-positive pole ear; 1322-negative pole ear; 14-welding area; 15-transition chamfer;

[0030] 2-shell; 3-top cover; 31-pole; 41-laminated battery core; 42-wound battery core; 5-adapter; 6-conductive block; 7-upper plastic; 8-liquid injection hole; 9-explosion-proof hole; 10-explosion-proof plate;

[0031] H1-weld mark height of the lug; H2-weld mark height of the welding area; H3-avoidance gap. DETAILED DESCRIPTION

[0032] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0033] Any feature disclosed in this specification, unless otherwise stated, may be replaced by other equivalent or alternative features having similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features. Throughout the specification, the same reference numerals indicate the same elements.

[0034] In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved more clearly, the technical solutions of the present invention are further explained below with reference to the accompanying drawings and through specific implementation methods.

[0035] Compared with traditional current collectors, composite current collectors have the characteristics of high safety, high energy density, low cost, long life and strong compatibility, which can greatly improve the puncture ability of battery cells. Therefore, composite current collectors are widely used in pole pieces; however, due to the substrate problem in the composite current collector, the use of composite current collectors in pole pieces will bring about the problem of larger internal resistance of the battery cell.

[0036] For this reason, Figures 1 to 7 As shown, in this embodiment, a pole piece 1 is proposed. Specifically, the pole piece 1 includes a composite current collector 11 and a foil 131. The composite current collector 11 has a first region and a second region located at the end. Active material layers 12 are respectively arranged on opposite sides of the first region of the composite current collector 11, and the second region is not provided with an active material layer 12, that is, the second region is a blank region; one end of the foil 131 is welded to the second region to form a welding region 14, and the other end of the foil 131 extends out of the second region to form a pole ear 132 to form a pole piece 1 with a complete structure; in the first direction, the width of the welding region 14 is greater than the width of the pole ear 132. Among them, the first direction is parallel to the width direction of the composite current collector 11, and the first direction is specifically as follows Figure 3 As shown by arrow A in FIG.

[0037] Compared with the prior art, the pole piece 1 in this embodiment increases the width of the welding area 14 while using the composite current collector 11 to improve the puncture ability of the battery cell; by making the width of the welding area 14 between the foil 131 and the composite current collector 11 larger than the width of the pole ear 132 in the first direction, the current conduction area can be increased by increasing the width of the welding area 14, thereby reducing the internal resistance of the battery cell, thereby solving the problem of large internal resistance of the battery cell caused by using the composite current collector 11 in the pole piece 1, and ensuring that the battery cell has both high puncture ability and low internal resistance. Among them, the puncture ability of the battery cell specifically refers to the ability to withstand internal short circuits of the battery cell; the structure of the composite current collector 11 is "metal-PET / PP-metal", that is, a layer of copper or aluminum of about 1um is plated on the upper and lower sides of the middle base film (PET or PP film) to form a composite structure.

[0038] It is worth noting that the tab 132 is actually a part of the foil 131 , that is, the tab 132 is formed by cutting the foil 131 .

[0039] Furthermore, if Figure 3 and Figure 4 As shown, a transition chamfer 15 is formed at the connection between the welding area 14 and the pole lug 132. Compared with directly setting it as a right angle, it can avoid the connection between the pole lug 132 and the welding area 14 from breaking, thereby improving the quality of the entire pole piece 1. Here, the specific size of the transition chamfer 15 is not limited, as long as the transition chamfer 15 is formed at the connection between the welding area 14 and the pole lug 132.

[0040] Specifically, when preparing the electrode 1, the two layers of foil 131 are first welded to the second region of the composite current collector 11, that is, a layer of foil 131 is welded on opposite sides of the second region of the composite current collector 11, such as Figure 1 and Figure 2 Then cutting is performed, that is, the weld stamp and the portion of the foil 131 extending from the composite current collector 11 are cut, so that the above-mentioned welding area 14 and the above-mentioned pole ear 132 can be formed by cutting, as shown Figure 3 and Figure 4 Wherein, the above-mentioned transition chamfer 15 is also formed by cutting.

[0041] Furthermore, if Figure 3 As shown, after cutting, in the second direction, the welding height of the tab 132 is higher than the welding height of the welding area 14. By setting the welding height, it is possible to avoid the appearance of multiple burrs on the edge of the welding area 14 during the cutting process, and ensure that the peripheral edge of the welding area 14 is relatively smooth. The second direction is parallel to the length direction of the composite current collector 11. The second direction is specifically as follows Figure 3 As shown by arrow B in FIG.

[0042] Specifically, the weld mark refers to the surface morphology change caused by the flow and crystallization of the metal due to high temperature during the welding process, which usually presents an uneven imprint; wherein the weld mark height of the tab 132 is as follows: Figure 3 As shown in the mark H1 in the figure, it can be 6.5 mm; the weld mark height of the welding area 14 is as follows Figure 3 As shown by the mark H2 in FIG. 1 , the specific length may be 3 mm.

[0043] It is worth noting that if Figure 1 As shown, a layer of foil 131 is welded on the opposite sides of the second region on the composite current collector 11, and the two foils 131 are electrically connected through the composite current collector 11, that is, during the roll welding process of the composite current collector 11 and the foil 131, a number of point welding heads are pressed on the foil 131 and the composite current collector 11 to form a number of through holes, and the foil 131 is heated and flows into the through holes under the action of the welding head, so that the foils 131 on both sides of the composite current collector 11 are electrically connected, thereby ensuring the conductivity of the electrode sheet 1; wherein, one of the two foils 131 with a longer length forms the above-mentioned pole ear 132.

[0044] The battery cell in this embodiment includes a diaphragm, a positive electrode sheet and a negative electrode sheet. The diaphragm is arranged between the positive electrode sheet and the negative electrode sheet to achieve insulation protection between the positive electrode sheet and the negative electrode sheet. Figure 3 and Figure 4 As shown, the positive electrode sheet and / or the negative electrode sheet is the electrode sheet 1 as described above; the electrode ear 132 can conduct electricity outward, and the electrode ear 132 includes a positive electrode ear 1321 and a negative electrode ear 1322, the positive electrode ear 1321 is arranged on the positive electrode sheet, and the negative electrode ear 1322 is arranged on the negative electrode sheet.

[0045] Specifically, for different types of battery cells, the arrangement of the welding area 14 is different; for example, Figure 3 and Figure 4 As shown, when the battery cell is a laminated battery cell 41, the laminated battery cell 41 specifically refers to a plurality of positive electrode sheets and a plurality of negative electrode sheets cross-stacked.

[0046] Furthermore, if Figure 3 and Figure 4 As shown, when the positive electrode ear 1321 and the negative electrode ear 1322 in the laminated battery cell 41 are located on the same side, and the positive electrode sheet is the above-mentioned electrode sheet 1, that is, the current collector in the positive electrode sheet adopts the composite current collector 11; Figure 4 As shown in the mark in, the horizontal interval between the edge of the welding area 14 and the negative electrode ear 1322 is 4mm-6mm, so as to avoid the welding area 14 and the negative electrode ear 1322 directly contacting each other to cause a short circuit, thereby ensuring the safety of the battery cell while ensuring the low internal resistance of the battery cell. At this time, the negative electrode sheet is a common electrode sheet 1 structure in the prior art.

[0047] Specifically, when the positive electrode ear 1321 and the negative electrode ear 1322 in the laminated battery cell 41 are located on the same side, and the negative electrode sheet is the above-mentioned electrode sheet 1, that is, the current collector in the negative electrode sheet adopts the composite current collector 11; the horizontal interval between the edge of the welding area 14 and the positive electrode ear 1321 is 4mm-6mm, so as to avoid the welding area 14 and the positive electrode ear 1321 directly contacting and causing a short circuit, thereby ensuring the safety of the battery cell while ensuring the low internal resistance of the battery cell. At this time, the positive electrode sheet is a common electrode sheet 1 structure in the prior art.

[0048] Specifically, when the positive electrode ear 1321 and the negative electrode ear 1322 in the stacked battery cell 41 are located on the same side, and the positive electrode sheet and the negative electrode sheet are respectively the above-mentioned electrode sheets 1, that is, the current collectors in the positive electrode sheet and the negative electrode sheet both use a composite current collector 11; the horizontal spacing between the edge of the welding area 14 on the positive electrode sheet and the edge of the welding area 14 on the negative electrode sheet is 4mm-6mm, so as to avoid direct contact between the two welding areas 14 and cause a short circuit, thereby ensuring the safety of the battery cell while ensuring a low internal resistance of the battery cell.

[0049] Furthermore, when the positive electrode ear 1321 and the negative electrode ear 1322 in the stacked battery cell 41 are located on different sides, the positive electrode sheet and / or the negative electrode sheet is the electrode sheet 1. Since it is not necessary to avoid the electrode ear 132 or the welding area 14 on the same side at this time, in the first direction, the width of the welding area 14 on the positive electrode sheet and / or the width of the welding area 14 on the negative electrode sheet is equal to the side length of the composite current collector 11 on which the foil 131 is welded.

[0050] That is, the welding area 14 can cover the entire side of the composite current collector 11, so as to further increase the width of the welding area 14 to increase the current conduction area, thereby better reducing the internal resistance of the battery cell and better solving the problem of large internal resistance of the battery cell caused by using the composite current collector 11 in the electrode 1.

[0051] Furthermore, if Figure 5 and Figure 6 As shown, when the battery cell is a wound battery cell 42, the wound battery cell 42 specifically refers to a battery cell formed by winding a plurality of positive electrode sheets and a plurality of negative electrode sheets crosswise and stacked, and then winding from one end to form a rolled battery cell; a plurality of positive electrode ears 1321 are arranged on the positive electrode sheet, and a plurality of negative electrode ears 1322 are arranged on the negative electrode sheet. After the positive electrode sheet and the negative electrode sheet are stacked together, the positive electrode ears 1321 and the negative electrode ears 1322 are crosswise arranged. After the positive electrode sheet and the negative electrode sheet are wound, all the positive electrode ears 1321 are aligned, and all the negative electrode ears 1322 are also aligned. In this embodiment, three positive electrode ears 1321 are arranged on the positive electrode sheet.

[0052] Specifically, if Figure 5 and Figure 6As shown, when the positive electrode ear 1321 and the negative electrode ear 1322 in the wound battery cell 42 are located on the same side, and the positive electrode sheet and / or the negative electrode sheet is the above-mentioned electrode sheet 1, as shown in FIG. Figure 6 As shown in the markings in , one side of the welding area 14 of each positive ear 1321 / negative ear 1322 is spaced 4mm-6mm away from the adjacent negative ear 1322 / positive ear 1321, and the other side of the welding area 14 of each positive ear 1321 / negative ear 1322 is spaced 4mm-6mm away from the corresponding adjacent negative ear 1322 / positive ear 1321, or the welding area 14 of the positive ear 1321 is spaced 4mm-6mm away from the welding area 14 of the adjacent negative ear 1322, thereby avoiding direct contact between the welding area 14 and the ear 132 or between two adjacent welding areas 14 to cause a short circuit, thereby ensuring the safety of the battery cell.

[0053] Furthermore, when the positive electrode ear 1321 and the negative electrode ear 1322 in the wound battery cell 42 are located on different sides, and the positive electrode sheet and / or the negative electrode sheet is the electrode sheet 1, the situation is similar to that of the above-mentioned stacked battery cell 41. Since there is no need for the electrode ears 132 or the welding area 14 to avoid each other on the same side at this time, in the first direction, the width of the welding area 14 on the positive electrode sheet and / or the width of the welding area 14 on the negative electrode sheet is equal to the side length of the composite current collector 11 on which the foil 131 is welded, so that the width of the welding area 14 can be further increased to increase the current conduction area, thereby better reducing the internal resistance of the battery cell and better solving the problem of large internal resistance of the battery cell caused by the use of the composite current collector 11 in the electrode sheet 1.

[0054] This embodiment also provides a battery, including the battery cell as described above, such as Figure 7 As shown, the battery further includes a shell 2 and a top cover 3, the battery cell is arranged in the shell 2, and the top cover 3 is arranged on the open end of the shell 2 to ensure the sealing of the battery; the pole ear 132 on the battery cell is used to be electrically connected to the pole 31 on the top cover 3. Among them, the pole ear 132 and the pole 31 are electrically connected through the adapter 5, so that the battery cell can supply power to the external electrical device through the adapter 5 and the pole 31. In this embodiment, the external electrical device can be an electric lamp.

[0055] It is worth noting that if Figure 7 As shown, the battery also includes an explosion-proof plate 10, a conductive block 6 and an upper plastic 7 commonly found in existing battery structures, and a liquid injection hole 8 and an explosion-proof hole 9 are provided on the top cover 3 respectively; other structures in the battery are not described in detail here, and reference can be made to the existing battery structure.

[0056] Furthermore, if Figure 3 , Figure 4 and Figure 7As shown, when the battery cell is a laminated battery cell 41, an abutting portion is provided on the top cover 3, and in the first direction, there is an escape gap between the edge of the composite current collector 11 on one side of which the foil 131 is provided and the edge of the welding area 14, so that the abutting portion abuts against the composite current collector 11, ensuring that the abutting portion does not abut against the welding area 14, thereby preventing the abutting portion from bending the welding area 14. In this embodiment, the escape gap is specifically Figure 3 Label H3 in the figure.

[0057] By providing the abutment portion, when the top cover 3 is covered to the open end of the shell 2, the abutment portion can be abutted against the battery cell, so that the battery cell is tightly pressed into the shell 2, thereby preventing the battery cell from shaking in the shell 2 and ensuring the installation stability of the battery cell in the shell 2. In this embodiment, the abutment portion can be specifically a protrusion provided on the bottom end surface of the top cover 3.

[0058] Furthermore, the top cover 3 faces the bottom end surface in the shell 2 and is provided with abutment parts at both ends. The two abutment parts are arranged opposite to each other so that the battery cell can be pressed simultaneously by the two abutment parts, thereby better ensuring the installation stability of the battery cell in the shell 2.

[0059] It is worth noting that since an abutment portion is provided in the laminated battery cell 41, that is, the welding area 14 needs to avoid the abutment portion, therefore, in the above-mentioned situation where the positive electrode ear 1321 and the negative electrode ear 1322 in the laminated battery cell 41 are located on different sides and the positive electrode sheet and / or the negative electrode sheet is the electrode sheet 1, the sum of the width of the welding area 14 on the positive electrode sheet and / or the width of the welding area 14 on the negative electrode sheet and the width of the avoidance gap is equal to the side length of the composite current collector 11 on which the foil 131 is welded.

[0060] The electrode piece 1 in this embodiment increases the current conduction area by setting a wider welding area 14, thereby reducing the internal resistance of the battery cell; and a transition chamfer 15 is formed at the connection between the welding area 14 and the pole ear 132 to avoid breakage at the connection between the pole ear 132 and the welding area 14; at the same time, it can avoid direct contact and short circuit between the welding area 14 and the pole ear 132 or between two welding areas 14, so that the safety of the battery cell and the battery is higher.

[0061] The above contents are only preferred embodiments of the present invention. For ordinary technicians in this field, according to the concept of the present invention, there will be changes in the specific implementation methods and application scopes. The contents of this specification should not be understood as limiting the present invention.

Claims

1. A pole piece, characterized in that: include: A composite current collector (11), the composite current collector (11) comprising a first region and a second region, active material layers (12) being respectively arranged on opposite sides of the first region of the composite current collector (11), and the active material layer (12) being not arranged in the second region; A foil (131), one end of the foil (131) is welded to the second region to form a welding region (14), the other end of the foil (131) extends out of the second region to form a pole ear (132), in a first direction, the width of the welding region (14) is greater than the width of the pole ear (132), and the first direction is parallel to the width direction of the composite current collector (11).

2. The pole piece according to claim 1, characterized in that: A transition chamfer (15) is formed at the connection between the welding area (14) and the pole lug (132).

3. The pole piece according to claim 1, characterized in that: In the second direction, the welding height of the pole tab (132) is higher than the welding height of the welding area (14), and the second direction is parallel to the length direction of the composite current collector (11).

4. The pole piece according to any one of claims 1 to 3, characterized in that: The foils (131) are welded respectively on two opposite sides of the second region of the composite current collector (11); the two foils (131) are electrically connected via the composite current collector (11); and one of the foils (131) with a longer length forms the electrode tab (132).

5. A battery cell, characterized in that: It comprises a diaphragm, a positive electrode sheet and a negative electrode sheet, wherein the diaphragm is arranged between the positive electrode sheet and the negative electrode sheet, and the positive electrode sheet and / or the negative electrode sheet is a electrode sheet as described in any one of claims 1 to 4; the electrode ear (132) comprises a positive electrode ear (1321) and a negative electrode ear (1322), wherein the positive electrode ear (1321) is arranged on the positive electrode sheet, and the negative electrode ear (1322) is arranged on the negative electrode sheet.

6. The battery cell according to claim 5, characterized in that: The positive electrode ear (1321) and the negative electrode ear (1322) are located on the same side, the positive electrode sheet is the electrode sheet, and the interval between the edge of the welding area (14) and the negative electrode ear (1322) is 4mm-6mm; or the negative electrode sheet is the electrode sheet, and the interval between the edge of the welding area (14) and the positive electrode ear (1321) is 4mm-6mm.

7. The battery cell according to claim 5, characterized in that: The positive electrode ear (1321) and the negative electrode ear (1322) are located on the same side, the positive electrode sheet and the negative electrode sheet are respectively the electrode sheets, and the interval between the welding area (14) on the positive electrode sheet and the welding area (14) on the negative electrode sheet is 4mm-6mm.

8. The battery cell according to claim 5, characterized in that: The positive electrode ear (1321) and the negative electrode ear (1322) are located on different sides, the positive electrode sheet and / or the negative electrode sheet are the electrode sheets, and in the first direction, the width of the welding area (14) on the positive electrode sheet and / or the width of the welding area (14) on the negative electrode sheet is equal to the side length of the composite current collector (11) on which the foil (131) is welded.

9. A battery, characterized in that The battery comprises a battery cell as claimed in any one of claims 5 to 8, wherein the battery cell further comprises a shell (2) and a top cover (3), wherein the battery cell is arranged in the shell (2), the top cover (3) is arranged to cover the open end of the shell (2), and the pole ear (132) on the battery cell is used to be electrically connected to the pole (31) on the top cover (3).

10. The battery according to claim 9, characterized in that The battery cell is a laminated battery cell (41), the top cover (3) is provided with an abutment portion, and in the first direction, an edge of one side of the composite current collector (11) on which the foil material (131) is provided has an avoidance gap with the edge of the welding area (14), so that the abutment portion abuts against the composite current collector (11).

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