Battery case and battery

Abstract

The utility model provides a battery case and a battery, the side wall of the battery case comprises a plurality of connecting parts which are arranged in sequence, and each connecting part comprises a first side facing an accommodating space. Wherein the first side comprises a plurality of first cambered surfaces and a plurality of second cambered surfaces, each first cambered surface is sunken towards the direction far away from the accommodating space, each second cambered surface is raised towards the direction of the accommodating space, and each third cambered surface is connected between two adjacent first cambered surfaces. The arc transition structure can disperse stress and effectively avoid stress concentration, so that the structural stability of the battery shell is improved.

Description

Technical Field

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

[0002] The battery case is one of the most important components of the battery, and has important functions such as protecting the internal battery cells, isolation, heat dissipation, waterproof and dustproof. In the design of the battery pack, it is necessary to reasonably design and select the appropriate shell material and structure to ensure the performance, life and safety of the battery pack.

[0003] In the related art, when the battery is in use, a large amount of heat will be generated inside the battery. The thermal shock caused by the heat energy will increase the probability of cracking of the battery shell, which will not only affect the performance and service life of the battery, but may even cause safety accidents. Utility Model Content

[0004] The embodiment of the utility model provides a battery shell, which can improve the technical problem that the battery shell is easy to crack.

[0005] In a first aspect, an embodiment of the present utility model provides a battery case, the battery case comprising:

[0006] bottom wall;

[0007] A side wall, arranged around the bottom wall, and surrounding the bottom wall to form a receiving space;

[0008] The side wall includes a plurality of connecting portions arranged in sequence along a first direction, the connecting portion includes a first side facing the accommodating space, the first side includes a plurality of first curved surfaces and a plurality of second curved surfaces, each of the first curved surfaces is recessed in a direction away from the accommodating space, each of the second curved surfaces is protruding in a direction toward the accommodating space, and each of the second curved surfaces is connected between two adjacent first curved surfaces.

[0009] In one embodiment, the connecting portion also includes a second side facing away from the accommodating space, the second side includes a plurality of third curved surfaces and a plurality of fourth curved surfaces, each of the third curved surfaces is recessed in a direction away from the accommodating space, each of the fourth curved surfaces is protruding in a direction of the accommodating space, and each of the fourth curved surfaces is connected between two adjacent third curved surfaces.

[0010] In one embodiment, each of the first arc surfaces is symmetrically arranged with the third arc surface, and each of the second arc surfaces is symmetrically arranged with the fourth arc surface.

[0011] In one embodiment, the relative distance between the fourth arc surface and the second arc surface is D1, the relative distance between the third arc surface and the first arc surface is D2, and the absolute value of the difference between D1 and D2 is less than or equal to 0.1 mm.

[0012] In one embodiment, along the first direction, the side wall includes two oppositely disposed ends and a middle portion located between the two ends, and the distance between the second arc surface of the middle portion and the fourth arc surface is greater than or equal to the distance between the second arc surface of at least one end and the fourth arc surface.

[0013] In one embodiment, the distance between the second arc surface and the fourth arc surface of one end portion is different from or the same as the distance between the second arc surface and the fourth arc surface of the other end portion.

[0014] In one embodiment, the side wall includes two first side walls arranged opposite to each other along a first direction and two second side walls arranged opposite to each other along a second direction, the second direction is perpendicular to the first direction, the second side walls are connected between the first side walls, the first side wall includes a plurality of connecting portions arranged sequentially along the first direction, and the second side wall includes a plurality of connecting portions arranged sequentially along the second direction.

[0015] In one embodiment, the thickness of the side wall close to the bottom wall is greater than the thickness of the side wall away from the bottom wall.

[0016] In one embodiment, the thickness of the side wall close to the bottom wall is D3, the thickness of the side wall away from the bottom wall is D4, and the absolute value of the difference between D3 and D4 is less than or equal to 0.15 mm.

[0017] In one embodiment, the arc curvature of the first arc surface is a first arc curvature, the arc curvature of the second arc surface is a second arc curvature, and the first arc curvature is less than or equal to the second arc curvature.

[0018] In a second aspect, an embodiment of the present utility model provides a battery, the battery comprising:

[0019] A battery case as described above;

[0020] An end cover is mounted on the battery shell

[0021] Beneficial effects of the embodiments of the utility model:

[0022] On the one hand, the present application provides a battery shell, the side wall of the battery shell includes a plurality of connection parts arranged in sequence, the connection parts include a first side facing the accommodation space and a second side away from the accommodation space; wherein the first side includes a first arc surface that is recessed in the direction away from the accommodation space, the first sides of two adjacent connection parts are smoothly transitioned, and a second arc surface is formed, the first arc surface and the second arc surface are smoothly transitioned, and the arc transition structure can disperse stress, effectively avoid stress concentration, and reduce the probability of gas cracking between the first arc surface and the second arc surface, thereby increasing the structural stability of the battery shell. On the other hand, the present application provides a battery, which has high structural strength, good thermal shock resistance, and high overall battery safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 It is a schematic diagram of the structure of a battery case provided by an embodiment of the utility model;

[0025] Figure 2 yes Figure 1 A top view of a provided battery case;

[0026] Figure 3 yes Figure 2 An enlarged schematic diagram a of a portion A of a battery shell is provided.

[0027] Figure 4 yes Figure 2 An enlarged schematic diagram b of a portion A of a battery shell is provided.

[0028] Figure 5 yes Figure 2 A cross-sectional view of a battery case along line AA is provided;

[0029] Figure 6 yes Figure 5 An enlarged schematic diagram of a portion B of the battery shell is provided.

[0030] Figure 7 It is a schematic diagram of the structure of a battery provided in an embodiment of the utility model.

[0031] Figure 8 yes Figure 7 Structural explosion diagram of the battery provided.

[0032] Reference numerals:

[0033] 100. battery case; 101. storage space;

[0034] 10. Bottom wall;

[0035] 20, side wall; 201, first side wall; 202, second side wall; 21, connecting portion; 211, first side; 2111, first arc surface; 2112, second arc surface; 212, second side; 2121, third arc surface; 2122, fourth arc surface; 22, end portion; 23, middle portion;

[0036] 200. Battery; 2001. End cap. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the utility model, and are not used to limit the utility model. In the utility model, unless otherwise stated, the directional words used, such as "upper" and "lower", generally refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the accompanying drawings; while "inside" and "outside" refer to the outline of the device.

[0038] The battery shell is one of the most important components of the battery. It has important functions such as protecting the internal battery cells, isolation, heat dissipation, waterproof and dustproof. In the design of the battery pack, it is necessary to reasonably design and select appropriate shell materials and structures to ensure the performance, life and safety of the battery pack. In the related technology, when the battery is in use, a large amount of heat will be generated inside the battery. The thermal shock caused by the heat energy will increase the probability of cracking of the battery shell, which will not only affect the performance and service life of the battery, but may even cause safety accidents.

[0039] See also Figure 1-Figure 3 , Figure 1 1 is a schematic diagram of the structure of a battery case 100 provided in an embodiment of the present utility model. Figure 2 yes Figure 1 A top view of the battery housing 100 is provided, Figure 3 yes Figure 2The present application provides a battery case 100, which includes a bottom wall 10 and a side wall 20. The side wall 20 is arranged around the bottom wall 10 and forms a receiving space 101 with the bottom wall 10. The receiving space 101 is used to place the battery cell. The side wall 20 includes a plurality of connecting portions 21 arranged in sequence along a first direction. The connecting portion 21 includes a first side 211 facing the receiving space 101. Please refer to Figure 4 , Figure 4 yes Figure 2 An enlarged schematic diagram b of a local A of the battery shell 100 is provided. Among them, the first side 211 includes a plurality of first curved surfaces 2111 and a plurality of second curved surfaces 2112, each of the first curved surfaces 2111 is recessed in the direction away from the accommodating space 101, and each of the second curved surfaces 2112 is protruding in the direction of the accommodating space 101, and each of the second curved surfaces 2112 is connected between two adjacent first curved surfaces 2111. It can be understood that when the first curved surface 2111 is recessed in the direction away from the accommodating space 101, the second curved surface 2112 protrudes in the direction of the accommodating space 101, and the first curved surface 2111 and the second curved surface 2112 form a wavy structure as a whole. In the related art, although the existing shell is set to a continuously bent structure to increase the heat dissipation area, its bending connection is mostly a pointed structure. It can be understood that, compared with the pointed structure, the smooth transition structure between the first curved surface 2111 and the second curved surface 2112 can disperse stress, effectively avoid stress concentration, and reduce the probability of gas cracking between the first curved surface 2111 and the second curved surface 2112, thereby increasing the structural stability of the battery shell 100 and ensuring the service life of the battery shell 100. In addition, when the heat inside the battery is transferred to the battery shell 100, the wavy structure can also increase the heat dissipation area and improve the heat dissipation effect.

[0040] In some embodiments, the connecting portion 21 also includes a second side 212 facing away from the accommodating space 101. While the first sides 211 of two adjacent connecting portions 21 transition smoothly and form a second curved surface 2112, the second side 212 is a straight structure, which can facilitate stacking of multiple battery shells 100.

[0041] In some embodiments, the connecting portion 21 also includes a second side 212 facing away from the accommodating space 101. While the first sides 211 of two adjacent connecting portions 21 smoothly transition and form a second arc surface 2112, the second side 212 includes a plurality of third arc surfaces 2121 and a plurality of fourth arc surfaces 2122. Each of the third arc surfaces 2121 is recessed in a direction away from the accommodating space 101, and each of the fourth arc surfaces 2122 is protruding in a direction toward the accommodating space 101. Each of the fourth arc surfaces 2122 is connected between two adjacent third arc surfaces 2121.

[0042] Specifically, in some embodiments, when the first curved surface 2111 is recessed in the direction away from the accommodating space 101 and the third curved surface 2121 is recessed in the accommodating direction, each first curved surface 2111 is stacked on the third curved surface 2121, and each second curved surface 2112 is stacked on the fourth curved surface 2122, that is, the first curved surface 2111 and the third curved surface 2121 are both recessed in the direction away from the accommodating space 101, and the second curved surface 2112 and the fourth curved surface 2122 are both recessed in the direction of the accommodating space 101.

[0043] In some embodiments, when the first curved surface 2111 is recessed in a direction away from the accommodation space 101, and the third curved surface 2121 is recessed in the accommodation direction, each first curved surface 2111 and the third curved surface 2121 are symmetrically arranged, and each second curved surface 2112 and the fourth curved surface 2122 are symmetrically arranged, so that the side wall 20 as a whole forms a wavy edge structure that is symmetrical inside and outside. Specifically, during the stretching process, the uneven flow of the material causes uneven shrinkage of the material, which will produce internal stress. The symmetrical structure of the present application can increase the thickness of the structure. During the manufacturing process, the thicker materials of the second curved surface 2112 and the fourth curved surface 2122 can diffuse toward the thinner first curved surface 2111 and the third curved surface 2121. On the one hand, this structure can improve the fluidity of the material during the manufacturing process and avoid the internal stress caused by uneven shrinkage of the material. On the other hand, it can also avoid the risk of damage during material processing.

[0044] In some embodiments, the relative distance between the fourth arc surface 2122 and the second arc surface 2112 is D1, the relative distance between the third arc surface 2121 and the first arc surface 2111 is D2, and the absolute value of the difference between D1 and D2 is less than 0.1 mm. Specifically, an assembly gap will be generated during laser welding. If the gap is too large, it will cause deformation and loss of the welding part; if the gap is too small, pores may appear at the welding point, affecting the welding quality. When |D2-D1| is less than or equal to 0.1 mm, the assembly gap can be avoided from further expansion. In addition, when |D2-D1| is less than or equal to 0.1 mm, the thickness difference of the side wall 20 will not be too large, reducing the impact on the further assembly of the battery shell 100, making the structural consistency better.

[0045] In some embodiments, the side wall 20 includes two first side walls 201 arranged oppositely along a first direction and two second side walls 202 arranged oppositely along a second direction, the second direction is perpendicular to the first direction, the second side wall 202 is connected between the first side walls 201, the first side wall 201 includes a plurality of connecting portions 21 arranged in sequence along the first direction, and the second side wall 202 includes a plurality of connecting portions 21 arranged in sequence along the second direction. Specifically, the first direction is the length direction of the battery shell 100, and the second direction is the width direction of the battery shell 100. The connecting portion 21 can be arranged on two opposite first side walls 201 along the first direction; or both the two first side walls 201 and the two second side walls 202 are provided with the connecting portion 21, that is, the connecting portion 21 is arranged on the opposite first side wall 201 along the first direction and the opposite second side wall 202 along the second direction. It can be understood that the heat dissipation area at the second side wall 202 can be further increased by providing the connecting portion 21 on the second side wall 202. The connection between the adjacent first side wall 201 and the second side wall 202 may be in the form of an arc transition to further reduce stress concentration.

[0046] In some embodiments, the length of the first side wall 201 is not less than twice the length of the second side wall 202, so that the battery shell 100 forms a rectangular structure as a whole. Specifically, most of the battery shells 100 on the current market are made by a stretching process. Due to the particularity of the process, the molding of the battery shell 100 depends on the flow of materials. However, as the aspect ratio of the battery shell 100 increases, the flow of materials such as aluminum alloys will become more difficult, and uneven material flow will cause deformation of the battery shell 100, which will cause assembly difficulties. The rectangular structure increases the extension length of the material flow process, which facilitates the molding of the battery shell 100.

[0047] In some embodiments, as the length of the side wall 20 increases, the number of connecting parts 21 can increase, and the number of connecting parts 21 can satisfy the relationship of a custom series, such as S=3+(N-1)2, where S is the number of connecting parts 21, and N is a positive integer. The number of connecting parts 21 can be 3, 5, 7, etc., and the present application does not limit the specific numerical value of the connecting part.

[0048] In some embodiments, the arc curvature of the first arc surface 2111 is the first arc curvature, the arc curvature of the second arc surface 2112 is the second arc curvature, and the first arc curvature is less than or equal to the second arc curvature. Specifically, in order to ensure that the material in the stretching process is better extended and flowed, the curvature of the connecting portion 21 is relatively small. It can be understood that the smaller the curvature, the smaller the arc curvature. Since the curvature of the first arc surface 2111 is less than or equal to the curvature of the second arc surface 2112, the first arc curvature is less than or equal to the second arc curvature.

[0049] In some embodiments, along the first direction, the side wall 20 includes two oppositely disposed end portions 22 and a middle portion 23 located between the two end portions 22, and the distance between the second arc surface 2112 and the fourth arc surface 2122 of the middle portion 23 is greater than or equal to the distance between the second arc surface 2112 and the fourth arc surface 2122 of at least one end portion 22. Specifically, the distance between the second arc surface 2112 and the fourth arc surface 2122 is the maximum distance between the second arc surface 2112 and the fourth arc surface 2122, that is, the distance between the midpoints of the two arc surfaces. Since the battery cells are mostly arranged in the middle of the accommodation space 101, the middle portion 23 is subjected to a large thermal shock force, and increasing the thickness of the middle portion 23 can further increase the structural strength of the battery shell 100.

[0050] It can be understood that when the first side wall 201 and the second side wall 202 are both provided with a connecting portion 21, along the second direction, the side wall 20 includes two oppositely arranged end portions 22 and a middle portion 23 located between the two end portions 22, and the distance between the second arc surface 2112 and the fourth arc surface 2122 of the middle portion 23 is greater than or equal to the distance between the second arc surface 2112 and the fourth arc surface 2122 of at least one end portion 22.

[0051] In some embodiments, the distance between the second arc surface 2112 and the fourth arc surface 2122 of the middle portion 23 can be greater than or equal to the distance between the second arc surface 2112 and the fourth arc surface 2122 of any one end portion 22, and can also be greater than or equal to the distance between the second arc surface 2112 and the fourth arc surface 2122 of the two end portions 22. When the distance between the second arc surface 2112 and the fourth arc surface 2122 of the middle portion 23 and the distance between the second arc surface 2112 and the fourth arc surface 2122 of the two end portions 22 are equal, the thickness between the middle portion 23 and the second arc surface 2112 and the fourth arc surface 2122 of the two end portions 22 is the same, and the same thickness can increase structural consistency.

[0052] In some embodiments, the distance between the second curved surface 2112 and the fourth curved surface 2122 of one end 22 is different from the distance between the second curved surface 2112 and the fourth curved surface 2122 of the other end 22. Specifically, the distance between the second curved surface 2112 and the fourth curved surface 2122 is the maximum distance between the second curved surface 2112 and the fourth curved surface 2122, that is, the distance between the midpoints of the two curved surfaces. The two ends 22 may be a first end 22(a) and a second end 22(b), and the distance between the second curved surface 2112 and the fourth curved surface 2122 of the first end 22(a) is greater than the distance between the second curved surface 2112 and the fourth curved surface 2122 of the second end 22(b), or the distance between the second curved surface 2112 and the fourth curved surface 2122 of the first end 22(a) is less than the distance between the second curved surface 2112 and the fourth curved surface 2122 of the second end 22(b).

[0053] It is understandable that when both the first side wall 201 and the second side wall 202 are provided with a connecting portion 21, along the second direction, the distance between the second arc surface 2112 and the fourth arc surface 2122 of one end 22 is different from the distance between the second arc surface 2112 and the fourth arc surface 2122 of the other end 22.

[0054] In some embodiments, the distance between the second curved surface 2112 and the fourth curved surface 2122 of one end 22 is the same as the distance between the second curved surface 2112 and the fourth curved surface 2122 of the other end 22. Specifically, the two ends 22 may be a first end 22(a) and a second end 22(b), and the distance between the second curved surface 2112 and the fourth curved surface 2122 of the first end 22(a) is the same as the distance between the second curved surface 2112 and the fourth curved surface 2122 of the second end 22(b), that is, the first end 22(a) and the second end 22(b) have the same thickness.

[0055] It can be understood that when both the first side wall 201 and the second side wall 202 are provided with a connecting portion 21, along the second direction, the distance between the second arc surface 2112 and the fourth arc surface 2122 of one end 22 is the same as the distance between the second arc surface 2112 and the fourth arc surface 2122 of the other end 22.

[0056] See also Figure 5 , Figure 6 , Figure 5 yes Figure 2 A cross-sectional view of the battery case 100 along AA is provided, Figure 6 yes Figure 5 A partial enlarged schematic diagram of a battery case 100 is provided. In some embodiments, the thickness of the side wall 20 close to the bottom wall 10 is greater than the thickness of the side away from the bottom wall 10. The thickness of the side wall 20 close to the bottom wall 10 is greater, which not only allows the side close to the bottom wall 10 to have sufficient strength to form a support for the battery case 100 during the stretching process, but also allows the other side of the relatively thin side wall 20 to dissipate surface heat, reduce the internal heat of the battery, and improve the heat dissipation effect, thereby improving the safe use performance of the battery.

[0057] In some embodiments, the thickness of the side wall 20 close to the bottom wall 10 is D3, the thickness of the side wall 20 away from the bottom wall 10 is D4, and the absolute value of the difference between D3 and D4 is less than or equal to 0.15mm. Specifically, the thickness of the side wall 20 can range from 0.3mm to 1.0mm, such as 0.3mm, 0.5mm, 0.7mm, 0.9mm, 1.0mm, and the value of D4 is 10% less than D3. The maximum value of D4 is 1.0mm, then |D4-D3|=0.1mm. Due to its own manufacturing process, D4 has a manufacturing tolerance. When the tolerance grade is precision grade F, the tolerance value is ±0.05mm, so |D3-D4| satisfies less than or equal to 0.15mm.

[0058] See also Figure 7 , Figure 8 , Figure 7 is a schematic diagram of the structure of a battery 200 provided in an embodiment of the utility model, Figure 8 yes Figure 7 The structural explosion diagram of the provided battery 200. The present application also provides a battery 200, which is a battery shell 100 as described above and an end cover 2001 installed on the battery shell 100, wherein the end cover 2001 is provided at the opening of the accommodating space 101. The end cover 2001 includes an end face facing away from the accommodating space 101, and terminals are provided at both ends of the end face. During the assembly process, such as riveting, injection molding and other processes, the area near the terminal is expanded by force, causing this area to become wider; an explosion-proof valve is provided in the middle of the end cover 2001, where due to the laser welding process, the local high temperature and rapid cooling cause uneven shrinkage, causing the local part to shrink and narrow; therefore, the edge of the end cover 2001 also forms a wavy edge structure that is partially wide and partially narrow, and forms a complementary structure with the wavy edge of the side wall 20 of the battery shell 100, thereby improving the welding yield of the shell cover with the battery shell 100, thereby reducing the manufacturing cost. It is understandable that the end cap 2001 and the battery shell 100 may have multiple welding points, and the end cap 2001 and the battery shell 100 are welded together by laser to form a complete battery 200 structure. The battery structure has high strength, good thermal shock resistance, and high overall battery safety.

[0059] The above is a detailed introduction to the embodiments of the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for technicians in this field, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A battery case, characterized in that: include: bottom wall; A side wall, arranged around the bottom wall, and surrounding the bottom wall to form a receiving space; The side wall includes a plurality of connecting portions arranged in sequence along a first direction, the connecting portion includes a first side facing the accommodating space, the first side includes a plurality of first curved surfaces and a plurality of second curved surfaces, each of the first curved surfaces is recessed in a direction away from the accommodating space, each of the second curved surfaces is protruding in a direction toward the accommodating space, and each of the second curved surfaces is connected between two adjacent first curved surfaces.

2. The battery case according to claim 1, characterized in that: The connecting portion also includes a second side facing away from the accommodating space, the second side includes a plurality of third curved surfaces and a plurality of fourth curved surfaces, each of the third curved surfaces is recessed in a direction away from the accommodating space, each of the fourth curved surfaces is protruding in a direction toward the accommodating space, and each of the fourth curved surfaces is connected between two adjacent third curved surfaces.

3. The battery case according to claim 2, characterized in that: Each of the first arc surfaces is symmetrically arranged with the third arc surface, and each of the second arc surfaces is symmetrically arranged with the fourth arc surface.

4. The battery case according to claim 3, characterized in that: The relative distance between the fourth arc surface and the second arc surface is D1, the relative distance between the third arc surface and the first arc surface is D2, and the absolute value of the difference between D1 and D2 is less than or equal to 0.1 mm.

5. The battery case according to any one of claims 3 to 4, characterized in that: Along the first direction, the side wall includes two oppositely arranged ends and a middle portion located between the two ends, and the distance between the second arc surface of the middle portion and the fourth arc surface is greater than or equal to the distance between the second arc surface of at least one end and the fourth arc surface.

6. The battery case according to claim 5, characterized in that: The distance between the second arc surface and the fourth arc surface of one end portion is different from or the same as the distance between the second arc surface and the fourth arc surface of the other end portion.

7. The battery case according to any one of claims 1 to 4, characterized in that: The side wall includes two first side walls arranged opposite to each other along a first direction and two second side walls arranged opposite to each other along a second direction, the second direction is perpendicular to the first direction, the second side walls are connected between the first side walls, the first side wall includes a plurality of connecting portions arranged sequentially along the first direction, and the second side wall includes a plurality of connecting portions arranged sequentially along the second direction.

8. The battery case according to any one of claims 1 to 4, characterized in that: The thickness of the side wall close to the bottom wall is greater than the thickness of the side wall away from the bottom wall.

9. The battery case according to claim 8, characterized in that: The thickness of the side wall close to the bottom wall is D3, the thickness of the side wall away from the bottom wall is D4, and the absolute value of the difference between D3 and D4 is less than or equal to 0.15 mm.

10. The battery case according to any one of claims 1 to 4, characterized in that: The arc curvature of the first arc surface is a first arc curvature, the arc curvature of the second arc surface is a second arc curvature, and the first arc curvature is less than or equal to the second arc curvature.

11. A battery, characterized in that: include: The battery case according to any one of claims 1 to 10; An end cover is mounted on the battery shell.

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