Battery monomer, battery device and electric device

Abstract

The utility model provides a battery monomer, a battery device and a power utilization device, and relates to the technical field of batteries. Each battery monomer comprises a shell, an electrode assembly and an end cover; an opening is formed in at least one end of the shell in the first direction; the electrode assembly is at least partially accommodated in the shell; the end cover covers the opening and comprises a cover body and a first extension part, the cover body is provided with a first surface facing the electrode assembly, the first extension part is connected to the first surface and extends towards the direction close to the electrode assembly in the first direction, and the first extension part is connected with the shell; in other words, the first extension part is connected with the shell, and the connection position of the end cover and the shell is further away from the top of the battery monomer, so that the capacity of the battery monomer for resisting external force is stronger, and the service life of the battery monomer is prolonged. Therefore, the reliability of the battery monomer is improved and the service life of the battery monomer is prolonged.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell, a battery device, and an electrical device. Background Art

[0002] Batteries are widely used in new energy vehicles, electronic devices, and other fields. As demand for batteries grows, higher requirements are placed on battery reliability. As market demands for longer battery life increase, so too are demands for battery reliability. Utility Model Content

[0003] The embodiments of the present application provide a battery cell, a battery device, and an electrical device, which can improve the reliability of the battery cell.

[0004] In a first aspect, an embodiment of the present application provides a battery cell, comprising a shell, an electrode assembly and an end cover; the shell is formed with an opening at at least one end along a first direction; the electrode assembly is at least partially accommodated in the shell; the end cover covers the opening, the end cover comprises a cover body and a first extension portion, the cover body has a first surface facing the electrode assembly, the first extension portion is connected to the first surface and extends in the first direction toward the electrode assembly, and the first extension portion is connected to the shell.

[0005] In the above technical solution, the end cover is formed with a first extension portion extending toward the electrode assembly, and is connected to the shell through the first extension portion, so that the connection position of the end cover and the shell is farther away from the side of the cover body of the end cover away from the electrode assembly. In other words, through the connection with the shell through the first extension portion, the connection position of the end cover and the shell is farther away from the top of the battery cell, so that the battery cell has a stronger ability to resist external forces, thereby improving the reliability of the battery cell and extending the service life of the battery cell.

[0006] In some embodiments of the first aspect of the present application, the first extension portion is welded to the shell to form a first connection portion, and along the first direction, the first connection portion is located on a side of the first surface facing the electrode assembly.

[0007] In the above technical solution, the first extension part is welded to the housing, making the connection between the first extension part and the housing more stable and reliable. By welding the first extension part and the housing, the sealing performance between the end cap and the housing can also be improved, thereby enhancing the sealing reliability between the end cap and the housing. The first connection part formed by welding the first extension part and the housing is located on the side of the first surface facing the electrode assembly, and the distance between the first connection part and the side of the cover body facing away from the electrode assembly is relatively far, improving the ability of the welding position between the end cap and the housing to withstand external forces, thereby reducing the risk that the welding position between the end cap and the housing fails to achieve long-life use of the battery cell due to defects caused by increased use time or external extrusion, thereby improving the service life and reliability of the battery cell.

[0008] In some embodiments of the first aspect of the present application, the electrode assembly includes a main body portion and a tab, the tab protrudes from the main body portion, the battery cell further includes an insulating member, and at least a part of the insulating member is disposed between the cover body and the main body portion; along the first direction, the insulating member has an abutting surface, and the abutting surface abuts against the main body portion.

[0009] In the above technical solution, the insulating member has an abutting surface that abuts against the main body portion, which is beneficial to improving the stability of the electrode assembly in the housing, reducing the degree of movement of the electrode assembly in the housing when the battery cell is in working conditions such as vibration and dropping, thereby improving the reliability of the battery cell.

[0010] In some embodiments of the first aspect of the present application, the insulating member includes an insulating body and an abutting portion, the abutting portion protrudes from the surface of the insulating body facing the electrode assembly, the abutting surface is formed at one end of the abutting portion facing away from the insulating body, and in the projection plane perpendicular to the second direction, the positive projection of the abutting portion at least partially overlaps with the positive projection of the tab, and the second direction is perpendicular to the first direction.

[0011] In the above technical solution, in the projection plane perpendicular to the second direction, the positive projection of the abutting portion at least partially overlaps with the positive projection of the tab, making the structure between the electrode assembly and the insulating member more compact, thereby making the structure inside the battery cell more compact, which is beneficial to improving the energy density of the battery cell.

[0012] In some embodiments of the first aspect of the present application, the insulating member includes two abutting portions, the two abutting portions are arranged at intervals along the second direction, and along the second direction, the first extension portions are provided on both opposite sides of the insulating member.

[0013] In the above technical solution, the insulating member includes two abutting portions arranged at intervals in the second direction, so that when the insulating member abuts against the main body portion of the electrode assembly, the force on the electrode assembly is more uniform, which is more conducive to improving the stability of the electrode assembly and further reducing the degree of movement of the electrode assembly in the housing under conditions such as vibration and dropping of the battery cell. First extension portions are provided on both opposite sides of the insulating member in the first direction, so that the housing and the end cover can be connected at multiple positions, improving the connection stability between the housing and the end cover.

[0014] In some embodiments of the first aspect of the present application, along the first direction, the distance between the surface of the insulating body facing the first surface and the abutting surface is H1, and H1 ≤ 20 mm.

[0015] In the above technical solution, along the first direction, the distance between the surface of the insulating body facing the first surface and the abutting surface is less than or equal to 20 mm, reducing the occupation of the internal space of the battery cell by the insulating member, being conducive to the battery cell having a higher energy density, and also enabling more electrolyte to be accommodated in the battery cell to improve the cycle performance of the battery cell.

[0016] In some embodiments of the first aspect of the present application, the first extension portion is welded to the housing to form a first connection portion. Along the first direction, the first connection portion is located on the side of the first surface facing the electrode assembly, and the abutting surface is closer to the first surface than the first connection portion.

[0017] In the above technical solution, the abutting surface is closer to the first surface than the first connection portion. When observed in the second direction, the insulating member can avoid the first connection portion, and when the first extension portion and the housing are welded, the risk of the welding high temperature damaging the insulating member is smaller, which is conducive to ensuring the insulating performance of the insulating member and the stability of the abutting surface abutting against the electrode assembly.

[0018] In some embodiments of the first aspect of the present application, the first extension portion is welded to the housing to form a first connection portion. Along the first direction, the first connection portion is located on the side of the first surface facing the electrode assembly; along the second direction, the insulating member has a second surface facing the first extension portion, and an avoidance groove is provided on the second surface, and at least a part of the projection of the first connection portion in the second direction is located in the avoidance groove, and the second direction is perpendicular to the first direction.

[0019] In the above technical solution, a relief groove is provided on the second surface of the insulating member facing the first extension portion, and at least a part of the projection of the first connecting portion in the second direction is located in the relief groove. The provision of the relief groove can avoid the first connecting portion, and when the first extension portion and the housing are welded, the risk of the welding high temperature damaging the insulating member is smaller, which is beneficial to ensuring the insulating performance of the insulating member and the stability of the abutting surface against the electrode assembly. Providing the relief groove can also reduce the weight of the insulating member, thereby improving the energy density of the battery cell. Providing the relief groove can also enable the battery cell to accommodate more electrolyte inside, which is beneficial to improving the cycle performance of the battery cell.

[0020] In some embodiments of the first aspect of the present application, along the third direction, the relief groove extends to two opposite surfaces of the insulating member, and both the first direction and the second direction are perpendicular to the third direction.

[0021] In the above technical solution, the relief groove extends to two opposite surfaces of the insulating member along the third direction, so that the size of the relief groove in the third direction is large enough, and the relief groove can avoid the first connecting portion to the greatest extent in the third direction. When the first extension portion and the housing are welded, the risk of the welding high temperature damaging the insulating member is smaller, which is beneficial to ensuring the insulating performance of the insulating member and the stability of the abutting surface against the electrode assembly. The relief groove extending to two opposite surfaces of the insulating member along the third direction can further reduce the weight of the insulating member, thereby further improving the energy density of the battery cell. The relief groove extending to two opposite surfaces of the insulating member along the third direction can also enable the battery cell to accommodate more electrolyte inside, which is beneficial to improving the cycle performance of the battery cell.

[0022] In some embodiments of the first aspect of the present application, the relief groove extends along the first direction to the abutting surface.

[0023] In the above technical solution, the relief groove extends along the first direction to the abutting surface, so that the size of the relief groove in the first direction is larger, and the relief groove can avoid the first connecting portion to a greater extent in the first direction. When the first extension portion and the housing are welded, the risk of the welding high temperature damaging the insulating member is smaller, which is beneficial to ensuring the insulating performance of the insulating member and the stability of the abutting surface against the electrode assembly. The relief groove extending to the abutting surface can further reduce the weight of the insulating member, thereby further improving the energy density of the battery cell. The relief groove extending to the abutting surface can also enable the battery cell to accommodate more electrolyte inside, which is beneficial to improving the cycle performance of the battery cell.

[0024] In some embodiments of the first aspect of the present application, along the second direction, there is a gap between the second surface and the first extension portion.

[0025] In the above technical solution, in the second direction, there is a gap between the second surface of the insulating member facing the first extension portion and the first extension portion, reducing the risk of high-temperature damage to the insulating member during the welding of the first extension portion and the housing, which is beneficial to ensuring the insulating performance of the insulating member.

[0026] In some embodiments of the first aspect of the present application, along the second direction, the size of the gap is H2, and 0.1 mm ≤ H2 ≤ 20 mm.

[0027] In the above technical solution, the gap between the second surface of the insulating member facing the first extension portion and the first extension portion in the second direction is greater than or equal to 0.1 mm, such that the distance between the insulating member and the first extension portion in the second direction is relatively far, reducing the risk of high-temperature damage to the insulating member during the welding of the first extension portion and the housing, which is beneficial to ensuring the insulating performance of the insulating member. The gap between the second surface of the insulating member facing the first extension portion and the first extension portion in the second direction is less than or equal to 20 mm, reducing the risk of short circuit at the gap due to the gap between the second surface and the first extension portion.

[0028] In some embodiments of the first aspect of the present application, the housing includes a side wall, the side walls are provided in one-to-one correspondence with the first extension portions, the side wall includes a wall body and a second extension portion, the second extension portion is provided at one end of the wall body facing the cover body along the first direction, and in a projection plane perpendicular to the thickness direction of the side wall, the positive projection of the second extension portion at least partially overlaps with the positive projection of the first extension portion.

[0029] In the above technical solution, the side walls and the first extension portions are provided in one-to-one correspondence, facilitating the connection between the housing and the first extension portions, which is beneficial to better connection stability between the housing and the end cover. The positive projections of the first extension portion and the second extension portion of the side wall at least partially overlap in a projection plane perpendicular to the thickness direction of the side wall, facilitating the connection between the side wall and the first extension portion. The overlapping portion of the first extension portion and the second extension portion can also play a role in blocking the leakage of battery cells, which is beneficial to improving the sealing performance of the battery cells.

[0030] In some embodiments of the first aspect of the present application, along the first direction, the second extension portion extends from the wall body to the cover body.

[0031] In the above technical solution, along the first direction, the second extension portion extends from the wall body to the cover body. During the assembly of the battery cell, the housing and the end cover can be positioned and fitted. The second extension portion extends from the wall body to the cover body, and the second extension portion can also play a role in blocking the leakage of battery cells to improve the sealing performance of the battery cells.

[0032] In some embodiments of the first aspect of the present application, the second extension portion is welded to the cover body to form a second connection portion.

[0033] In the above technical solution, the second extension portion is welded to the cover body to form a second connection portion, which is beneficial to improving the connection stability between the end cover and the housing and is beneficial to improving the sealing performance between the end cover and the housing.

[0034] In some embodiments of the first aspect of the present application, along the thickness direction of the side wall, the first extension portion is located outside the second extension portion, or the first extension portion is located inside the second extension portion.

[0035] In the above technical solution, along the thickness direction of the side wall, the first extension portion is located outside the second extension portion, or the first extension portion is located inside the second extension portion. The first extension portion and the second extension portion can block the leakage of battery cells, which is beneficial to improving the sealing performance of battery cells.

[0036] In some embodiments of the first aspect of the present application, the first extension portion includes a first part and a second part. The first part is connected to the first surface, and the second part is disposed at one end of the first part facing away from the first surface. In a projection plane perpendicular to the thickness direction of the side wall, the orthographic projection of the second extension portion and the orthographic projection of the second part at least partially overlap.

[0037] In the above technical solution, in a projection plane perpendicular to the thickness direction of the side wall, the orthographic projection of the second extension portion and the orthographic projection of the second part of the first extension portion at least partially overlap. When assembling the housing and the end cover, the first extension portion and the second extension portion can be used for positioning, which is convenient for assembling battery cells and also convenient for connecting the first extension portion and the side wall.

[0038] In some embodiments of the first aspect of the present application, along the thickness direction of the side wall, the second part is located outside the second extension portion.

[0039] In the above technical solution, along the thickness direction of the side wall, the second part is located outside the second extension portion, which is beneficial to improving the sealing performance of battery cells.

[0040] In some embodiments of the first aspect of the present application, the second part is welded to the wall body to form a first connection portion.

[0041] In the above technical solution, the second part is welded to the wall body to form a first connection portion, so that the connection position of the first connection portion and the housing is farther from the side of the cover body facing away from the electrode assembly, making the battery cell more resistant to external forces, thereby improving the reliability of the battery cell and extending the service life of the battery cell.

[0042] In some embodiments of the first aspect of the present application, the second extension portion abuts against one end of the first part facing away from the first surface.

[0043] In the above technical solution, the second extension portion abuts against one end of the first portion facing away from the first surface. When assembling the battery cell, the second extension portion and the first extension portion can be cooperatively positioned, thereby facilitating the assembly of the battery cell.

[0044] In some embodiments of the first aspect of the present application, along the thickness direction of the side wall, the second portion is located inside the second extension portion.

[0045] In the above technical solution, along the thickness direction of the side wall, the second portion is located inside the second extension portion. The second portion can play a role in preventing the leakage of the battery cell, which is beneficial to improving the sealing performance of the battery cell.

[0046] In some embodiments of the first aspect of the present application, the second extension portion and the first portion are welded to form a first connection portion.

[0047] In the above technical solution, the second extension portion and the first portion are welded to form a first connection portion, then welding can be performed from the outside of the housing, which is convenient for connecting the first extension portion and the housing and reduces the connection difficulty.

[0048] In some embodiments of the first aspect of the present application, the second portion abuts against one end of the wall body facing the cover body.

[0049] In the above technical solution, the second portion abuts against one end of the wall body facing the cover body. When assembling the battery cell, it is convenient to realize the positioning and cooperation between the end cover and the housing. The second portion can also play a role in preventing the leakage of the battery cell, which is beneficial to improving the sealing performance of the battery cell.

[0050] In some embodiments of the first aspect of the present application, along the first direction, the size of the first extension portion is H3, H3≥2mm, preferably, H3≤20mm.

[0051] In the above technical solution, the size of the first extension portion along the first direction is greater than or equal to 2mm, so that the distance between the connection position of the first extension portion and the housing and the side of the cover body facing away from the electrode assembly can be relatively far, making the battery cell more resistant to external forces, thereby improving the reliability of the battery cell and extending the service life of the battery cell. The size of the first extension portion along the first direction is less than or equal to 20mm, which controls the size of the end cover within a reasonable range and facilitates the processing of the end cover.

[0052] In some embodiments of the first aspect of the present application, the end cover includes a plurality of the first extension portions, and the plurality of the first extension portions are sequentially connected end to end along the circumference of the opening.

[0053] In the above technical solution, a plurality of first extension portions of the end cap are sequentially connected end to end along the circumference of the opening. Then, the housing and the first extension portions can be connected along the circumference of the opening, which is beneficial to improving the connection stability between the end cap and the housing. If the housing and the plurality of first extension portions are welded along the circumference of the opening, it not only makes the connection stability between the housing and the end cap better, but also makes the sealing performance between the end cap and the housing better. The plurality of first extension portions of the end cap are sequentially connected end to end along the circumference of the opening, and also enables the plurality of first extension portions and the cover body to jointly form a receiving cavity, which is beneficial to the end cap and the housing to form a larger receiving space. Then, more electrolyte can be accommodated inside the battery cell, which is beneficial to improving the cycling performance of the battery cell.

[0054] In some embodiments of the first aspect of the present application, the end cap includes two first extension portions arranged opposite to each other in the second direction and two first extension portions arranged opposite to each other in the third direction, and the first direction, the second direction, and the third direction are perpendicular to each other in pairs.

[0055] In the above technical solution, two opposite first extension portions are respectively provided on the end cap in the second direction and the third direction, so that the end cap and the housing can be connected at multiple positions, which is beneficial to improving the connection stability between the end cap and the housing.

[0056] In a second aspect, an embodiment of the present application provides a battery device, including the battery cell provided in any embodiment of the first aspect.

[0057] In the above technical solution, the end cap of the battery cell provided in the embodiment of the first aspect forms a first extension portion extending toward the electrode assembly. By connecting the first extension portion and the housing, the distance between the connection position of the end cap and the housing and the side of the cover body of the end cap facing away from the electrode assembly is farther, so that the battery cell has stronger resistance to external forces, thereby improving the reliability of the battery cell and extending the service life of the battery cell. The battery device equipped with this battery cell also has good reliability and a long service life.

[0058] In a third aspect, an embodiment of the present application provides an electrical device, including the battery cell provided in any embodiment of the first aspect.

[0059] In the above technical solution, the end cap of the battery cell provided in the embodiment of the first aspect forms a first extension portion extending toward the electrode assembly. By connecting the first extension portion and the housing, the distance between the connection position of the end cap and the housing and the side of the cover body of the end cap facing away from the electrode assembly is farther, so that the battery cell has stronger resistance to external forces, thereby improving the reliability of the battery cell and extending the service life of the battery cell. The electrical device powered by this battery cell has good power supply reliability. Description of the Drawings

[0060] To more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0061] Figure 1 Structural schematic diagram of a vehicle provided by some embodiments of the present application;

[0062] Figure 2 Explosion view of a battery device provided by some embodiments of the present application;

[0063] Figure 3 Explosion view of a battery cell provided by some embodiments of the present application;

[0064] Figure 4 Exploded view of an end cap and an insulating member provided by some embodiments of the present application;

[0065] Figure 5 View of the assembled end cap and insulating member along the first direction provided by some embodiments of the present application;

[0066] Figure 6 For Figure 5 Cross-sectional view taken along A1 - A1 direction in

[0067] Figure 7 Cross-sectional view of the cooperation of the end cap, insulating member and housing provided by some embodiments of the present application;

[0068] Figure 8 For Figure 7 Enlarged view at B1 in

[0069] Figure 9 View of the cooperation of the end cap and insulating member along the first direction provided by some other embodiments of the present application;

[0070] Figure 10 For Figure 9 Cross-sectional view taken along A2 - A2 direction in

[0071] Figure 11 Cross-sectional view of the cooperation of the end cap, insulating member and housing provided by some other embodiments of the present application;

[0072] Figure 12 For Figure 11 Enlarged view at B2 in

[0073] Figure 13 View of the assembled end cap and insulating member along the first direction provided by still some other embodiments of the present application;

[0074] Figure 14 is Figure 13 A sectional view in the A3 - A3 direction in [description of the figure];

[0075] Figure 15 is a sectional view after the end cap, insulating part and housing are assembled according to some other embodiments of the present application;

[0076] Figure 16 is Figure 15 an enlarged view at B3 in [description of the figure];

[0077] Figure 17 is Figure 15 a sectional view after the end cap, insulating part and housing are assembled and welded in [description of the figure];

[0078] Figure 18 is Figure 17 an enlarged view at B4 in [description of the figure];

[0079] Figure 19 is a view along the first direction after the end cap and insulating part are assembled according to some other embodiments of the present application;

[0080] Figure 20 is Figure 19 a sectional view in the A4 - A4 direction in [description of the figure];

[0081] Figure 21 is a sectional view after the end cap, insulating part and housing are assembled according to some other embodiments of the present application;

[0082] Figure 22 is Figure 21 an enlarged view at B5 in [description of the figure];

[0083] Figure 23 is Figure 21 a sectional view after the end cap, insulating part and housing are assembled and welded in [description of the figure];

[0084] Figure 24 is Figure 23 an enlarged view at B6 in [description of the figure];

[0085] Figure 25 is a view along the first direction after the end cap and insulating part are assembled according to some other embodiments of the present application;

[0086] Figure 26 is Figure 25 a sectional view in the A5 - A5 direction;

[0087] Figure 27 is a sectional view after the end cap, insulating part and housing are assembled according to some other embodiments of the present application;

[0088] Figure 28 is Figure 27 an enlarged view at B7 in [description of the figure];

[0089] Figure 29 For Figure 27 Cross-sectional view after the middle end cap, insulating part and housing are fitted and welded;

[0090] Figure 30 For Figure 29 Enlarged view at B8 in [the figure];

[0091] Figure 31 View of the assembled end cap and insulating part along the first direction provided by some other embodiments of the present application;

[0092] Figure 32 For Figure 31 Cross-sectional view along the A6 - A6 direction;

[0093] Figure 33 Cross-sectional view after the end cap, insulating part and housing are fitted in some other embodiments of the present application;

[0094] Figure 34 For Figure 33 Enlarged view at B9 in [the figure];

[0095] Figure 35 For Figure 33 Cross-sectional view after the middle end cap, insulating part and housing are fitted and welded;

[0096] Figure 36 For Figure 35 Enlarged view at B10 in [the figure];

[0097] [[ID=4)] Figure 37 View of the assembled end cap and insulating part along the first direction provided by yet some other embodiments of the present application;

[0098] Figure 38 For Figure 37 Cross-sectional view along the A7 - A7 direction;

[0099] Figure 39 Cross-sectional view after the end cap, insulating part and housing are fitted in some other embodiments of the present application;

[0100] Figure 40 For Figure 33 Enlarged view at B11 in [the figure];

[0101] Figure 41 For Figure 39 Cross-sectional view after the middle end cap, insulating part and housing are fitted and welded;

[0102] Figure 42 For Figure 41 Enlarged view at B12 in [the figure];

[0103] Figure 43 For Figure 37 Cross-sectional view along the A8 - A8 direction in [the figure].

[0104] Icons: 1000 - vehicle; 100 - battery device; 10 - box; 11 - first box; 12 - second box; 20 - battery cell; 21 - outer shell; 211 - housing; 2111 - opening; 2112 - side wall; 21121 - wall body; 21122 - second extension; 21123 - outer side surface of the wall body; 21124 - outer side surface of the second extension; 21125 - inner side surface of the wall body; 21126 - inner side surface of the second extension; 212 - end cap; 2121 - cap body; 21211 - first surface; 21212 - outer peripheral surface of the cap body; 21213 - first region; 21214 - second region; 2122 - first extension; 21221 - outer side surface of the first extension; 21222 - inner side surface of the first extension; 21223 - first part; 21224 - second part; 22 - electrode assembly; 221 - main body part; 222 - tab; 23 - electrode terminal; 24 - current collector member; 25 - insulating member; 251 - abutting surface; 252 - insulating body; 253 - abutting part; 254 - second surface; 200 - controller; 300 - motor; X - first direction; Y - second direction; Z - third direction; Q1 - first connection part; Q2 - avoidance groove; Q3 - gap; Q4 - second connection part. Detailed implementation

[0105] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, rather than all of them. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of this application.

[0106] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by those skilled in the technical field to which this application belongs; the terms used in the description of this application in the specification are only for the purpose of describing specific embodiments, and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the description and claims of this application and the above drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the description and claims of this application or the above drawings are used to distinguish different objects, rather than to describe a specific order or primary-secondary relationship.

[0107] References to "embodiments" in this application mean that the specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of this application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments.

[0108] In the description of this application, it should be noted that unless otherwise clearly specified and limited, the terms "mounted", "connected", "connected to", and "attached" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0109] The term "and / or" in this application is merely an associative relationship describing the associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates an "or" relationship between the associated objects before and after.

[0110] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, in different embodiments, the detailed description of the same components is omitted. It should be understood that the thickness, length, width, etc. of various components in the embodiments of this application shown in the drawings, as well as the overall thickness, length, width, etc. of the integrated device, are only illustrative and should not constitute any limitation to this application.

[0111] The term "a plurality of" that appears in this application refers to two or more (including two).

[0112] In the embodiments of this application, the battery cell can be a secondary battery, which refers to a battery cell that can be activated by charging after discharging to continue use.

[0113] The battery cell includes but is not limited to lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium-metal batteries, sodium-metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, etc.

[0114] The battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are embedded and extracted back and forth between the positive electrode and the negative electrode. The separator is disposed between the positive electrode and the negative electrode, which can reduce the risk of short circuit between the positive and negative electrodes and at the same time allow active ions to pass through.

[0115] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material provided on at least one surface of the positive electrode current collector.

[0116] As an example, the positive electrode current collector has two surfaces opposite to each other in its own thickness direction, and the positive electrode active material is provided on any one or both of the two opposite surfaces of the positive electrode current collector.

[0117] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. can be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as substrates of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0118] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other conventional materials that can be used as the positive electrode active material of the battery monomer can also be used. These positive electrode active materials can be used alone or in combination of two or more. Among them, examples of lithium-containing phosphates may include, but are not limited to, lithium iron phosphate (such as LiFePO4 (which can also be abbreviated as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3Mn 1 / 3 O2 (which can also be abbreviated as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (which can also be abbreviated as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (which can also be abbreviated as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2O2 (which can also be abbreviated as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (which can also be abbreviated as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2), and at least one of its modified compounds, etc.

[0119] In some embodiments, the positive electrode can be made of porous metal. The porous metal can be porous nickel, porous copper, porous aluminum, porous alloy, etc. When the porous metal is used as the positive electrode, the positive electrode active material may not be provided on the surface of the porous metal, and of course, the positive electrode active material can also be provided. As an example, a lithium source material, potassium metal or sodium metal can also be filled and / or deposited in the porous metal, and the lithium source material is lithium metal and / or lithium-rich material.

[0120] In some embodiments, the negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative electrode current collector.

[0121] As an example, the negative electrode current collector can be made of a metal foil, porous metal or composite current collector. For example, as the metal foil, aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. can be used. The porous metal can be porous nickel, porous copper, porous aluminum, porous alloy, etc. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (such as copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0122] As an example, the negative electrode sheet can include a negative electrode current collector and a negative electrode active material provided on at least one surface of the negative electrode current collector.

[0123] As an example, the negative electrode current collector has two surfaces opposite to each other in its own thickness direction, and the negative electrode active material is provided on any one or both of the two opposite surfaces of the negative electrode current collector.

[0124] As an example, the negative electrode active material can be the negative electrode active material for battery cells known in the art. As an example, the negative electrode active material can include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. The silicon-based materials can be selected from at least one of elemental silicon, silicon oxides, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based materials can be selected from at least one of elemental tin, tin oxides, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as the negative electrode active material of battery cells can also be used. These negative electrode active materials can be used alone or in combination of two or more.

[0125] In some embodiments, the material of the positive electrode current collector can be aluminum, and the material of the negative electrode current collector can be copper.

[0126] In some embodiments, the separator is a separator membrane. The separator membrane can be any known porous structure separator membrane with good chemical stability and mechanical stability.

[0127] As an example, the material of the separator membrane can include at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator membrane can be a single-layer film or a multi-layer composite film. When the separator membrane is a multi-layer composite film, the materials of each layer can be the same or different. The separator can be a single component located between the positive and negative electrodes or attached to the surfaces of the positive and negative electrodes.

[0128] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive electrode and the negative electrode, and simultaneously plays the role of transmitting ions and isolating the positive and negative electrodes.

[0129] In some embodiments, the battery cell further includes an electrolyte, and the electrolyte plays the role of conducting ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like, or solid. Among them, the liquid electrolyte includes electrolyte salts and solvents.

[0130] In some embodiments, the electrolyte salts can include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium bis(oxalato)borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0131] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. The ether solvent may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether, and crown ether.

[0132] Among them, the gel electrolyte includes a polymer as the skeleton network of the electrolyte, combined with an ionic liquid-lithium salt.

[0133] Among them, the solid electrolyte includes a polymer solid electrolyte, an inorganic solid electrolyte, and a composite solid electrolyte.

[0134] As an example, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, single-ion polymer, polyionic liquid-lithium salt, cellulose, etc.

[0135] As an example, the inorganic solid electrolyte may include an oxide solid electrolyte (crystalline perovskite, sodium superionic conductor, garnet, amorphous LiPON film), a sulfide solid electrolyte (crystalline lithium superionic conductor (lithium germanium phosphorus sulfur, argyrodite), amorphous sulfide), and one or more of a halide solid electrolyte, a nitride solid electrolyte, and a hydride solid electrolyte.

[0136] As an example, the composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to the polymer solid electrolyte.

[0137] In some embodiments, the electrode assembly is a wound structure. The positive electrode sheet and the negative electrode sheet are wound into a wound structure.

[0138] In some embodiments, the electrode assembly is a stacked structure.

[0139] As an example, a plurality of positive electrode sheets and a plurality of negative electrode sheets may be respectively provided, and the plurality of positive electrode sheets and the plurality of negative electrode sheets are alternately stacked.

[0140] As an example, a plurality of positive electrode sheets may be provided, and the negative electrode sheet is folded to form a plurality of folded segments arranged in a stacked manner, and a positive electrode sheet is clamped between adjacent folded segments.

[0141] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of folded segments arranged in a stacked manner.

[0142] As an example, multiple separators may be provided and respectively disposed between any adjacent positive electrode plates or negative electrode plates.

[0143] As an example, the separators may be continuously provided and disposed between any adjacent positive electrode plates or negative electrode plates by folding or winding.

[0144] In some embodiments, the shape of the electrode assembly may be cylindrical, flat, prismatic, or the like.

[0145] In some embodiments, the electrode assembly is provided with tabs, and the tabs can conduct current out of the electrode assembly. The tabs include positive tabs and negative tabs.

[0146] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell), or an aluminum-plastic film, etc.

[0147] As an example, the battery cell may be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell, or a battery cell of other shapes. The prismatic battery cell includes a square-shell battery cell, a blade-shaped battery cell, a multi-prismatic battery cell, and the multi-prismatic battery cell is, for example, a hexagonal-prismatic battery cell, etc.

[0148] The battery apparatus mentioned in the embodiments of the present application may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly may include multiple battery cells, and the multiple battery cells are connected in series, parallel, or in a hybrid connection through a busbar component.

[0149] In some embodiments, the battery cell assembly is generally formed by arranging multiple battery cells; as an example, the battery cell assembly may be a battery module, and the battery module is formed by arranging and fixing multiple battery cells into an independent module.

[0150] As an example, the battery module may be formed by bundling multiple battery cells with cable ties.

[0151] In some embodiments, the battery device may be a battery pack, and the battery pack may include a box body and one or more battery cell assemblies, and the battery cell assemblies are accommodated in the box body.

[0152] As an example, the battery cell assembly may be a battery module, and the battery cell assembly may be accommodated in the box body by fixing the battery module in the box body.

[0153] As an example, the battery cell assembly can also be accommodated in the box by directly fixing a plurality of battery cells to the box.

[0154] As an example, the box can include a first box and a second box. The first box and the second box are snapped together so that a closed space is formed inside the box to accommodate the battery cell assembly. Here, "closed" means covered or closed, which can be sealed or non-sealed. The first box can be a top cover or a bottom plate.

[0155] As an example, the box can include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are respectively connected to the frame so that a closed space is formed inside the box to accommodate the battery cell assembly.

[0156] As an example, the box can be part of the chassis structure of a vehicle. For example, the top cover of the box can become at least part of the floor of the vehicle, or the frame of the box can become at least part of the cross beams and longitudinal beams of the vehicle.

[0157] In some embodiments, the battery device refers to an energy storage device, and the energy storage device includes a box with a door provided on at least one side thereof. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0158] The battery has outstanding advantages such as high energy density, low environmental pollution, high power density, long service life, wide adaptability, and small self-discharge coefficient, and is an important part of the development of new energy today. The development of battery technology needs to consider various design factors at the same time. For example, performance parameters such as energy density, cycle life, discharge capacity, charge and discharge rate, etc. In addition, the reliability of the battery also needs to be considered.

[0159] In battery technology, for a general battery cell, the battery cell includes a housing and an end cap. The housing has an open end, and the end cap covers the open end of the housing so that the end cap and the housing are connected to form a space for accommodating the electrode assembly. Among them, the connection method between the end cap and the housing can be that the surface of the end cap facing the electrode assembly is connected to the open end of the housing, or the outer peripheral surface of the end cap and the inner peripheral surface of the housing are connected, so that the end cap and the housing form a space for accommodating the electrode assembly. The connection between the surface of the end cap facing the electrode assembly and the open end of the housing, and the connection between the outer peripheral surface of the end cap and the inner peripheral surface of the housing both make the connection position between the end cap and the housing closer to the side of the end cap facing away from the electrode assembly, resulting in a weaker ability of the battery cell to resist external forces. The connection position between the end cap and the housing may have defects as the service life of the battery cell extends, or under external extrusion, resulting in a reduction in the reliability and service life of the battery cell.

[0160] In view of this, in order to alleviate the problem that as the service life of the battery cell extends, or in the case of external extrusion, defects may occur due to the weak ability of the connection position between the housing and the end cover to resist external forces, resulting in a reduction in the reliability and service life of the battery cell, an embodiment of the present application provides a battery cell. The battery cell includes a housing, an electrode assembly, and an end cover. At least one end of the housing in the first direction is formed with an opening; at least a part of the electrode assembly is accommodated in the housing; the end cover covers the opening. The end cover includes a cover body and a first extension portion. The cover body has a first surface facing the electrode assembly. The first extension portion is connected to the first surface and extends in the first direction towards the electrode assembly. The first extension portion is connected to the housing.

[0161] The end cover is formed with a first extension portion extending towards the electrode assembly. By connecting the first extension portion to the housing, the connection position between the end cover and the housing is farther from the side of the cover body of the end cover facing away from the electrode assembly. In other words, by connecting the first extension portion to the housing, the connection position between the end cover and the housing is farther from the top of the battery cell, making the battery cell more capable of resisting external forces, thereby improving the reliability of the battery cell and extending the service life of the battery cell.

[0162] The technical solutions described in the embodiments of the present application are applicable to various electrical devices using battery cells and battery devices. For example, mobile phones, portable devices, laptop computers, battery cars, electric toys, power tools, vehicles, ships, and spacecrafts, etc. For example, spacecrafts include airplanes, rockets, space shuttles, and spaceships, etc.

[0163] For the convenience of description in the following embodiments, a vehicle is taken as an example of the electrical device for illustration.

[0164] Please refer to Figure 1 , Figure 1 which is a schematic structural diagram of a vehicle 1000 provided by some embodiments of the present application. A battery device 100 is disposed inside the vehicle 1000. The battery device 100 can be disposed at the bottom, head, or tail of the vehicle 1000. The battery device 100 can be used for power supply of the vehicle 1000. For example, the battery device 100 can be used as the operating power source of the vehicle 1000.

[0165] The vehicle 1000 may further include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300. For example, it is used for the working power requirements during the start, navigation, and driving of the vehicle 1000.

[0166] In some embodiments of the present application, the battery device 100 can not only be used as the operating power source of the vehicle 1000, but also be used as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0167] Please refer to Figure 2 , Figure 2 which is an exploded view of the battery device 100 provided for some embodiments of the present application. The battery device 100 may include a box body 10 and battery cells 20, and the box body 10 is used to accommodate the battery cells 20.

[0168] Wherein, a closed space for accommodating the battery cells 20 is formed inside the box body 10. The box body 10 can adopt various structures. In some embodiments, the box body 10 may include a first box body 11 and a second box body 12, and the first box body 11 and the second box body 12 are buckled with each other. The first box body 11 and the second box body 12 can be of various shapes, such as a cuboid, a cylinder, etc. The first box body 11 may be a hollow structure with one side open, and the second box body 12 may also be a hollow structure with one side open. The open side of the second box body 12 and the open side of the first box body 11 are buckled with each other, then the box body 10 with a closed space is formed. It can also be that the first box body 11 is a hollow structure with one side open, and the second box body 12 is a plate-like structure. The second box body 12 is buckled on the open side of the first box body 11, then the box body 10 with an accommodation space is formed.

[0169] In the battery device 100, the battery cells 20 can be one or multiple. If there are multiple battery cells 20, the multiple battery cells 20 can be connected in series, in parallel or in a mixed connection. A mixed connection means that there are both series and parallel connections among the multiple battery cells 20. It can be that multiple battery cells 20 are first connected in series, in parallel or in a mixed connection to form a battery module, and then multiple battery modules are connected in series, in parallel or in a mixed connection to form a whole and are accommodated in the box body 10. It can also be that all the battery cells 20 are directly connected in series, in parallel or in a mixed connection together, and then the whole formed by all the battery cells 20 is accommodated in the box body 10.

[0170] In some embodiments, the battery device 100 may further include a busbar component (not shown in the figure). The multiple battery cells 20 can be electrically connected through the busbar component to achieve series, parallel or mixed connection of the multiple battery cells 20. The busbar component can be a metal conductor, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0171] Please refer to Figure 3 , Figure 3 which is an exploded view of the battery cell 20 provided for some embodiments of the present application. The battery cell 20 may include a housing 21 and an electrode assembly 22, and the electrode assembly 22 is accommodated in the housing 21.

[0172] In some embodiments, the housing 21 may include a shell 211 and an end cap 212. The shell 211 has an opening 2111, and the end cap 212 closes the opening 2111 of the shell 211. Here, "closing" means covering or closing, which can be a seal or a non-seal.

[0173] The housing 211 is a component for accommodating the electrode assembly 22. The housing 211 can be a hollow structure with an opening 2111 formed at one end, or a hollow structure with openings 2111 formed at opposite ends. The housing 211 can be of various shapes, such as cylindrical, cuboid, etc. The material of the housing 211 can be various, such as copper, iron, aluminum, steel, aluminum alloy, etc. The electrode assembly 22 can be partially located inside the housing 211 or entirely located inside the housing 211.

[0174] The end cap 212 and the housing 211 jointly define a receiving space for accommodating the electrode assembly 22 and other components. The end cap 212 can be connected to the housing 211 by means such as welding and rolling sealing to close the opening 2111 of the housing 211. The shape of the end cap 212 can be adapted to the shape of the housing 211. For example, when the housing 211 is a cuboid structure, the end cap 212 is a rectangular plate-like structure adapted to the housing 211. Another example is that when the housing 211 is a cylindrical structure, the end cap 212 is a circular plate-like structure adapted to the housing 211. The material of the end cap 212 can also be various, such as copper, iron, aluminum, steel, aluminum alloy, etc. The material of the end cap 212 and the housing 211 can be the same or different.

[0175] In an embodiment where the housing 211 has an opening 2111 formed at one end, one end cap 212 can be correspondingly provided. In an embodiment where the housing 211 has openings 2111 formed at opposite ends, two end caps 212 can be correspondingly provided. The two end caps 212 respectively close the two openings 2111 of the housing 211, and the two end caps 212 and the housing 211 jointly define the receiving space.

[0176] In some embodiments, the battery cell 20 can further include electrode terminals 23. The electrode terminals 23 are provided on the housing 21 and are used to electrically connect to the tabs 222 of the electrode assembly 22 to input or output the electrical energy of the battery cell 20. The electrode terminals 23 can be provided on the housing 211 of the housing 21 or on the end cap 212 of the housing 21. The electrode terminals 23 and the tabs 222 can be directly connected. For example, the electrode terminals 23 and the tabs 222 are welded. The electrode terminals 23 and the tabs 222 can also be indirectly connected. For example, the electrode terminals 23 and the tabs 222 are indirectly connected through a current collecting member 24. The current collecting member 24 can be a metal conductor, such as copper, iron, aluminum, steel, aluminum alloy, etc.

[0177] As an example, such as Figure 3As shown, one end of the housing 211 forms an opening 2111. There is one end cap 212 in the outer housing 21, and the end cap 212 closes one opening 2111 of the housing 211. Two electrode terminals 23 are provided on the end cap 212. The two electrode terminals 23 are a positive electrode terminal and a negative electrode terminal respectively. One end of the electrode assembly 22 facing the end cap 212 forms a positive electrode tab and a negative electrode tab. The positive electrode terminal is electrically connected to the positive electrode tab, and the negative electrode terminal is electrically connected to the negative electrode tab.

[0178] Please refer to Figures 3 - 8 , an embodiment of the present application provides a battery cell 20. The battery cell 20 includes a housing 211, an electrode assembly 22, and an end cap 212. At least one end of the housing 211 forms an opening 2111 along the first direction X. The electrode assembly 22 is at least partially accommodated in the housing 211. The end cap 212 covers the opening 2111. The end cap 212 includes a cap body 2121 and a first extension portion 2122. The cap body 2121 has a first surface 21211 facing the electrode assembly 22. The first extension portion 2122 is connected to the first surface 21211 and extends in the first direction X towards the electrode assembly 22. The first extension portion 2122 is connected to the housing 211.

[0179] One end of the housing 211 may form an opening 2111 along the first direction X, or both ends may form openings 2111. The end caps 212 of the end cap 212 and the housing 211 are provided in one-to-one correspondence, and the end cap 212 covers the corresponding opening 2111.

[0180] Along the first direction X, a part of the electrode assembly 22 may be located inside the housing 211, and another part of the electrode assembly 22 extends out of the housing 211 from the opening 2111 along the first direction X. Of course, the electrode assembly 22 may also be completely accommodated in the housing 211.

[0181] The end cap 212 includes a cap body 2121 and a first extension portion 2122. The cap body 2121 is arranged facing the opening 2111. The first direction X may be parallel to the thickness direction of the cap body 2121. The first extension portion 2122 is connected to the first surface 21211 of the end cap 212 facing the electrode assembly 22. The first extension portion 2122 and the end cap 212 may be fixedly connected, such as by welding or bonding. The first extension portion 2122 and the end cap 212 may also be detachably connected, such as by snap connection or screw connection. The first extension portion 2122 and the end cap 212 may also be integrally formed.

[0182] The end cap 212 may include a first extension portion 2122, or may include a plurality of first extension portions 2122. In an embodiment where the end cap 212 includes a plurality of first extension portions 2122, a plurality of first connection portions Q1 may be spaced apart on the first surface 21211 of the cap body 2121, and the plurality of first connection portions Q1 may also be connected as a whole.

[0183] Along the first direction X, the first extension portion 2122 extends from the first surface 21211 in a direction approaching the electrode assembly 22, and the connection position of the first extension portion 2122 and the housing 211 is located on the side of the cap body 2121 facing the electrode assembly 22. In some embodiments, the first extension portion 2122 and the housing 211 may be hermetically connected, that is, the connection between the first extension portion 2122 and the housing 211 can not only fix the end cap 212 and the housing 211, but also achieve sealing between the end cap 212 and the housing 211. In other embodiments, the connection between the first extension portion 2122 and the housing 211 may only fix the end cap 212 and the housing 211.

[0184] The end cap 212 is formed with a first extension portion 2122 extending towards the electrode assembly 22. By connecting the first extension portion 2122 and the housing 211, the connection position between the end cap 212 and the housing 211 is farther from the side of the cap body 2121 of the end cap 212 facing away from the electrode assembly 22. In other words, by connecting the first extension portion 2122 and the housing 211, the connection position between the end cap 212 and the housing 211 is farther from the top of the battery cell 20, making the battery cell 20 more resistant to external forces, thereby improving the reliability of the battery cell 20 and extending the service life of the battery cell 20.

[0185] As Figure 8 shown, in some embodiments, the first extension portion 2122 and the housing 211 are welded to form a first connection portion Q1. Along the first direction X, the first connection portion Q1 is located on the side of the first surface 21211 facing the electrode assembly 22.

[0186] The first extension portion 2122 and the housing 211 are welded. For example, the first extension portion 2122 and the housing 211 can be welded by means such as laser welding and penetration welding.

[0187] Along the first direction X, the first connection portion Q1 is located on the side of the first surface 21211 facing the electrode assembly 22. In other words, along the first direction X, there is a distance between the first connection portion Q1 and the first surface 21211.

[0188] The first extension portion 2122 is welded to the housing 211, making the connection between the first extension portion 2122 and the housing 211 more stable and reliable. By welding the first extension portion 2122 and the housing 211, the sealing performance between the end cap 212 and the housing 211 can also be improved, thereby enhancing the sealing reliability between the end cap 212 and the housing 211. The first connection portion Q1 formed by welding the first extension portion 2122 and the housing 211 is located on the side of the first surface 21211 facing the electrode assembly 22. The distance between the first connection portion Q1 and the side of the cover body 2121 facing away from the electrode assembly 22 is relatively far, improving the ability of the welding position between the end cap 212 and the housing 211 to withstand external forces, thereby reducing the risk that the welding position between the end cap 212 and the housing 211 fails to achieve long-life use of the battery cell 20 due to defects caused by increased use time or external extrusion, thus improving the service life and reliability of the battery cell 20.

[0189] As Figure 7 , Figure 8 shown, in some embodiments, the electrode assembly 22 includes a main body portion 221 and a tab 222. The tab 222 protrudes from the main body portion 221. The battery cell 20 further includes an insulating member 25. At least a part of the insulating member 25 is disposed between the cover body 2121 and the main body portion 221; along the first direction X, the insulating member 25 has a contact surface 251, and the contact surface 251 abuts against the main body portion 221.

[0190] The main body portion 221 of the electrode assembly 22 includes a region of the positive electrode sheet having an active material, a region of the negative electrode sheet having an active material, and at least a part of the separator. Along the first direction X, the tab 222 is connected to the portion of the electrode sheet located in the main body portion 221 and protrudes from the main body portion 221 along the first direction X.

[0191] The insulating member 25 can be partially disposed between the cover body 2121 and the main body portion 221, or can be entirely disposed between the cover body 2121 and the main body portion 221. The insulating member 25 can insulate and separate the end cap 212 and the electrode assembly 22 to reduce the risk of short circuit of the battery cell 20, which is beneficial to improving the reliability of the battery cell 20. The insulating member 25 can be connected to the end cap 212. Exemplarily, the insulating member 25 is connected to the first surface 21211. There are various ways for the insulating member 25 to be connected to the end cap 212. For example, the insulating member 25 is adhered to the end cap 212. The insulating member 25 can also be connected to the end cap 212 by injection molding.

[0192] A part of the surface of the insulating member 25 facing the main body portion 221 abuts against the main body portion 221. The surface of the insulating member 25 that abuts against the main body portion 221 is the contact surface 251. In some embodiments, the contact surface 251 is the surface that is farthest from the first surface 21211 among all the surfaces of the insulating member 25 facing the main body portion 221.

[0193] The insulating part 25 has a resting surface 251, which rests against the main body 221, which is beneficial to improving the stability of the electrode assembly 22 in the shell 211 and reducing the degree of movement of the electrode assembly 22 in the shell 211 when the battery cell 20 is in vibration, falling and other working conditions, thereby improving the reliability of the battery cell 20.

[0194] like Figures 6 - 8 As shown, in some embodiments, the insulating member 25 includes an insulating body 252 and a supporting portion 253, the supporting portion 253 protrudes from the surface of the insulating body 252 facing the electrode assembly 22, and the supporting surface 251 is formed at one end of the supporting portion 253 away from the insulating body 252. In the projection plane perpendicular to the second direction Y, the positive projection of the supporting portion 253 at least partially overlaps with the positive projection of the pole ear 222, and the second direction Y is perpendicular to the first direction X.

[0195] The abutting portion 253 protrudes along the first direction X from the surface of the insulating body 252 facing the electrode assembly 22 toward the direction close to the electrode assembly 22, so that the end of the abutting portion 253 facing away from the insulating body 252 abuts against the main body 221. The insulating member 25 may include one abutting portion 253, or may include multiple abutting portions 253. In the embodiment where the insulating member 25 includes multiple abutting portions 253, the multiple abutting portions 253 are spaced apart on the insulating body 252, and each abutting portion 253 can abut against the main body 221, thereby achieving simultaneous abutment of multiple positions of the main body 221, which is beneficial to improving the uniformity of the force applied to the main body 221 and the stability of the electrode assembly 22 in the shell 211.

[0196] The abutting portion 253 may be connected to an edge of the insulating body 252 so that the side surface of the abutting portion 253 is flush with the outer circumference of the insulating body 252. The abutting portion 253 may also be connected to the middle area of the insulating body 252.

[0197] In the projection plane perpendicular to the second direction Y, the orthographic projection of the abutment portion 253 at least partially overlaps with the orthographic projection of the tab 222, making the structure between the electrode assembly 22 and the insulating member 25 more compact, thereby making the structure inside the battery cell 20 more compact, which is beneficial to improving the energy density of the battery cell 20.

[0198] like Figure 6 As shown, in some embodiments, the insulating member 25 includes two abutting portions 253 , which are spaced apart along the second direction Y. Along the second direction Y, the first extending portions 2122 are provided on opposite sides of the insulating member 25 .

[0199] The second direction Y is perpendicular to the first direction X. For example, Figure 3 、 Figure 6 、 Figure 8As shown, in the embodiment where the battery cell 20 is a square-shell battery, the second direction Y may be the length direction of the battery cell 20. The two end faces of the insulating body 252 along the second direction Y are flush with the side faces of the two abutting parts 253 respectively.

[0200] The insulating member 25 includes two abutting parts 253 arranged at intervals along the second direction Y, so that when the insulating member 25 abuts against the main body part 221 of the electrode assembly 22, the electrode assembly 22 is more uniformly stressed, which is more beneficial to improving the stability of the electrode assembly 22, and further reducing the degree of the electrode assembly 22 moving around in the housing 211 when the battery cell 20 is in working conditions such as vibration and dropping. Both sides of the insulating member 25 along the first direction X are provided with first extension parts 2122, so that the housing 211 and the end cover 212 can be connected at multiple positions, improving the connection stability between the housing 211 and the end cover 212.

[0201] As Figure 8 shown, in some embodiments, along the first direction X, the distance between the surface of the insulating body 252 facing the first surface 21211 and the abutting surface 251 is H1, and H1 ≤ 20 mm.

[0202] Exemplarily, the distance H1 between the surface of the insulating body 252 facing the first surface 21211 and the abutting surface 251 may be 1 mm, 3 mm, 5 mm, 7 mm, 9 mm, 11 mm, 13 mm, 15 mm, 17 mm, 20 mm, etc.

[0203] Along the first direction X, the distance between the surface of the insulating body 252 facing the first surface 21211 and the abutting surface 251 is less than or equal to 20 mm, reducing the occupation of the internal space of the battery cell 20 by the insulating member 25, which is beneficial for the battery cell 20 to have a higher energy density, and also enables more electrolyte to be accommodated in the battery cell 20 to improve the cycle performance of the battery cell 20.

[0204] As Figure 8 shown, in some embodiments, the first extension part 2122 is welded to the housing 211 to form a first connection part Q1. Along the first direction X, the first connection part Q1 is located on the side of the first surface 21211 facing the electrode assembly 22, and the abutting surface 251 is closer to the first surface 21211 than the first connection part Q1.

[0205] The abutting surface 251 is closer to the first surface 21211 than the first connection part Q1 means that along the first direction X, the position where the abutting surface 251 is closest to the first surface 21211 is closer to the first surface 21211 than the first connection part Q1. As Figure 8As shown, along the first direction X, the distance between the first connecting portion Q1 and the first surface 21211 is D1, and the distance between the abutting surface 251 and the first surface 21211 is D2, where D1 > D2. In an embodiment where the surface of the insulating body 252 facing away from the abutting portion 253 is in contact with the first surface 21211, the distance D2 between the abutting surface 251 and the first surface 21211 is the same as the distance H1 between the surface of the insulating body 252 facing the first surface 21211 and the abutting surface 251.

[0206] The abutting surface 251 is closer to the first surface 21211 than the first connecting portion Q1. When observed along the second direction Y, the insulating member 25 can avoid the first connecting portion Q1, and when the first extension portion 2122 and the housing 211 are welded, the risk of the welding high temperature damaging the insulating member 25 is smaller, which is beneficial to ensuring the insulating performance of the insulating member 25 and the stability of the abutting surface 251 abutting against the electrode assembly 22.

[0207] As Figures 9 - 12 As shown, in some embodiments, the first extension portion 2122 and the housing 211 are welded to form the first connecting portion Q1. Along the first direction X, the first connecting portion Q1 is located on the side of the first surface 21211 facing the electrode assembly 22; along the second direction Y, the insulating member 25 has a second surface 254 facing the first extension portion 2122, and an avoidance groove Q2 is provided on the second surface 254. At least a part of the projection of the first connecting portion Q1 along the second direction Y is located in the avoidance groove Q2, and the second direction Y is perpendicular to the first direction X.

[0208] The second surface 254 can be a partial area of the outer peripheral surface of the insulating member 25. The avoidance groove Q2 is recessed from the second surface 254 in a direction away from the first extension portion 2122. In an embodiment where the side surface of the abutting portion 253 is flush with the outer peripheral surface of the insulating body 252, a part of the outer peripheral surface of the insulating body 252 and the side surface of the abutting portion 253 facing the first extension portion 2122 and closest to the first extension portion 2122 together form the second surface 254. In the first direction X, the avoidance groove Q2 can be entirely located in the insulating body 252 and recessed from the outer peripheral surface of the insulating body 252 in a direction away from the first extension portion 2122; or, the avoidance groove Q2 can be entirely located in the abutting portion 253 and recessed from the side surface of the abutting portion 253 facing the first extension portion 2122 and closest to the first extension portion 2122 in a direction away from the first extension portion 2122; or, a part of the avoidance groove Q2 is entirely located in the insulating body 252 and recessed from the outer peripheral surface of the insulating body 252 in a direction away from the first extension portion 2122, and the other part is located in the abutting portion 253 and recessed from the side surface of the abutting portion 253 facing the first extension portion 2122 and closest to the first extension portion 2122 in a direction away from the first extension portion 2122.

[0209] The second surface 254 of the insulating member 25 facing the first extension portion 2122 is provided with an avoidance groove Q2. The projection of the first connection portion Q1 along the second direction Y is at least partially located within the avoidance groove Q2. The provision of the avoidance groove Q2 can avoid the first connection portion Q1. When the first extension portion 2122 and the housing 211 are welded, the risk of the welding high temperature damaging the insulating member 25 is smaller, which is beneficial to ensuring the insulating performance of the insulating member 25 and the stability of the abutting surface 251 abutting against the electrode assembly 22. Providing the avoidance groove Q2 can also reduce the weight of the insulating member 25, thereby improving the energy density of the battery cell 20. Providing the avoidance groove Q2 can also enable the battery cell 20 to accommodate more electrolyte inside, which is beneficial to improving the cycle performance of the battery cell 20.

[0210] In some embodiments, along the third direction Z, the avoidance groove Q2 extends to two opposite surfaces of the insulating member 25, and both the first direction X and the second direction Y are perpendicular to the third direction Z.

[0211] If the avoidance groove Q2 extends to two opposite surfaces of the insulating member 25 along the third direction Z, then both ends of the avoidance groove Q2 along the third direction Z are open.

[0212] The avoidance groove Q2 extends to two opposite surfaces of the insulating member 25 along the third direction Z, such that the size of the avoidance groove Q2 in the third direction Z is large enough. In the third direction Z, the avoidance groove Q2 can avoid the first connection portion Q1 to the greatest extent. When the first extension portion 2122 and the housing 211 are welded, the risk of the welding high temperature damaging the insulating member 25 is smaller, which is beneficial to ensuring the insulating performance of the insulating member 25 and the stability of the abutting surface 251 abutting against the electrode assembly 22. The avoidance groove Q2 extending to two opposite surfaces of the insulating member 25 along the third direction Z can further reduce the weight of the insulating member 25, thereby further improving the energy density of the battery cell 20. The avoidance groove Q2 extending to two opposite surfaces of the insulating member 25 along the third direction Z can also enable the battery cell 20 to accommodate more electrolyte inside, which is beneficial to improving the cycle performance of the battery cell 20.

[0213] Of course, the avoidance groove Q2 can also extend to any one surface of the insulating member 25 along the third direction Z, then one end of the avoidance groove Q2 along the third direction Z is open and the other end is closed. The avoidance groove Q2 can also not extend to any one surface of the insulating member 25 along the third direction Z, then both ends of the avoidance groove Q2 along the third direction Z are closed.

[0214] As Figure 12 shown, in some embodiments, the avoidance groove Q2 extends along the first direction X to the abutting surface 251.

[0215] If the avoidance groove Q2 extends along the first direction X to the abutting surface 251, then one end of the avoidance groove Q2 facing the electrode assembly 22 is open.

[0216] The avoidance groove Q2 extends along the first direction X to the abutting surface 251, such that the size of the avoidance groove Q2 in the first direction X is larger. In the first direction X, the avoidance groove Q2 can avoid the first connecting portion Q1 to a greater extent. When the first extension portion 2122 and the housing 211 are welded, the risk of the welding high temperature damaging the insulating member 25 is smaller, which is beneficial to ensuring the insulating performance of the insulating member 25 and the stability of the abutting surface 251 abutting against the electrode assembly 22. The avoidance groove Q2 extending to the abutting surface 251 can further reduce the weight of the insulating member 25, thereby further improving the energy density of the battery cell 20. The avoidance groove Q2 extending to the abutting surface 251 can also enable the battery cell 20 to accommodate more electrolyte inside, which is beneficial to improving the cycling performance of the battery cell 20.

[0217] As Figure 12 shown, in some embodiments, along the second direction Y, there is a gap Q3 between the second surface 254 and the first extension portion 2122.

[0218] In the embodiment where the avoidance groove Q2 is provided on the second surface 254, there being a gap Q3 between the second surface 254 and the first extension portion 2122 means that there is a gap Q3 along the second direction Y between the region of the second surface 254 where the avoidance groove Q2 is not provided and the first extension portion 2122.

[0219] In the second direction Y, there is a gap Q3 between the second surface 254 of the insulating member 25 facing the first extension portion 2122 and the first extension portion 2122, reducing the risk of the high temperature during welding of the first extension portion 2122 and the housing 211 damaging the insulating member 25, which is beneficial to ensuring the insulating performance of the insulating member 25.

[0220] As Figure 12 shown, in some embodiments, the size of the gap Q3 is H2, and 0.1 mm ≤ H2 ≤ 20 mm.

[0221] Exemplarily, the size H2 of the gap Q3 can be 0.1 mm, 2 mm, 4 mm, 6 mm, 8 mm, 10 mm, 12 mm, 14 mm, 16 mm, 18 mm, 20 mm, etc.

[0222] The clearance Q3 between the second surface 254 of the insulating member 25 facing the first extension portion 2122 in the second direction Y and the first extension portion 2122 is greater than or equal to 0.1 mm, so that the distance between the insulating member 25 and the first extension portion 2122 is relatively large in the second direction Y, reducing the risk of high-temperature damage to the insulating member 25 during the welding of the first extension portion 2122 and the housing 211, which is beneficial to ensuring the insulating performance of the insulating member 25. The clearance Q3 between the second surface 254 of the insulating member 25 facing the first extension portion 2122 in the second direction Y and the first extension portion 2122 is less than or equal to 20 mm, reducing the risk of short circuit at the clearance Q3 caused by the existence of the clearance Q3 between the second surface 254 and the first extension portion 2122.

[0223] As Figures 13 - 16 shown, in some embodiments, the housing 211 includes side walls 2112, the side walls 2112 are arranged in one-to-one correspondence with the first extension portions 2122, the side walls 2112 include wall bodies 21121 and second extension portions 21122, the second extension portions 21122 are arranged at one end of the wall bodies 21121 facing the cover body 2121 along the first direction X, and in the projection plane perpendicular to the thickness direction of the side walls 2112, the orthographic projection of the second extension portions 21122 at least partially overlaps with the orthographic projection of the first extension portions 2122.

[0224] Along the first direction X, at least one end of all the side walls 2112 encloses an opening 2111 of the housing 211. In the embodiment where the battery cell 20 is a square shell battery cell, the housing 211 includes four side walls 2112, and the four side walls 2112 are sequentially connected end to end along the circumference of the opening 2111. The housing 211 includes two side walls 2112 arranged opposite to each other along the second direction Y and two side walls 2112 arranged opposite to each other along the third direction Z. The end cover 212 may include four first extension portions 2122, two of the four first extension portions 2122 are arranged opposite to each other along the second direction Y, and the other two of the four first extension portions 2122 are arranged opposite to each other along the third direction Z, and the first direction X, the second direction Y and the third direction Z are perpendicular to each other in pairs. Each side wall 2112 is connected to the corresponding first extension portion 2122.

[0225] As Figure 14 、 Figure 15As shown, along the thickness direction of the side wall 2112, the thickness of the wall body 21121 is greater than that of the second extension part 21122. The outer side surface 21123 of the wall body and the outer side surface 21124 of the second extension part may be flush, or the inner side surface 21125 of the wall body is flush with the inner side surface 21126 of the second extension part. The outer side surface 21123 of the wall body refers to the side surface of the wall body 21121 away from the electrode assembly 22 in the thickness direction of the side wall 2112. The outer side surface 21124 of the second extension part refers to the side surface of the second extension part 21122 away from the electrode assembly 22 in the thickness direction of the side wall 2112. The inner side surface 21125 of the wall body refers to the side surface of the wall body 21121 close to the electrode assembly 22 in the thickness direction of the side wall 2112. The inner side surface 21126 of the second extension part refers to the side surface of the second extension part 21122 close to the electrode assembly 22 in the thickness direction of the side wall 2112.

[0226] It should be further noted that in the embodiments of the present application, the outer side surface and the inner side surface of the structure involved respectively refer to that in the thickness direction of the structure, the side surface farthest from the electrode assembly 22 is the outer side surface, and the side surface closest to the electrode assembly 22 is the inner side surface.

[0227] In the projection plane perpendicular to the thickness direction of the side wall 2112, the positive projection of the second extension part 21122 and the positive projection of the first extension part 2122 at least partially overlap, which means that in the projection plane perpendicular to the thickness direction of the side wall 2112, the positive projection of the second extension part 21122 of each side wall 2112 of the housing 211 and the positive projection of the corresponding first extension part 2122 at least partially overlap. In the embodiment where the battery cell 20 is a square shell battery cell, the thickness direction of the side wall 2112 in the second direction Y is parallel to the second direction Y, and the thickness direction of the side wall 2112 in the third direction Z is parallel to the third direction Z. In the embodiment where the battery cell 20 is a cylindrical battery cell 20, the thickness directions at different positions of the side wall 2112 are different, but the thickness direction at any position of the side wall 2112 is perpendicular to the first direction X.

[0228] The side wall 2112 and the first extension part 2122 are arranged in one-to-one correspondence, which is convenient for connecting the housing 211 and the first extension part 2122, and is beneficial to better connection stability between the housing 211 and the end cover 212. The positive projections of the first extension part 2122 and the second extension part 21122 of the side wall 2112 at least partially overlap in the projection plane perpendicular to the thickness direction of the side wall 2112, which is convenient for connecting the side wall 2112 and the first extension part 2122. The overlapping part of the first extension part 2122 and the second extension part 21122 can also play a role in blocking the leakage of the battery cell 20, which is beneficial to improving the sealing performance of the battery cell 20.

[0229] Such as Figures 16 - 30As shown, in some embodiments, along the first direction X, the second extension portion 21122 extends from the wall body 21121 to the cover body 2121.

[0230] As Figure 16 shown, in some embodiments, along the first direction X, the second extension portion 21122 extends from the wall body 21121 to the cover body 2121. One end of the second extension portion 21122 facing away from the wall body 21121 is flush with the cover body 2121 facing away from the first surface 21211. The inner side surface 21126 of the second extension portion is in contact with the outer peripheral surface 21212 of the cover body, and the inner side surface 21126 of the second extension portion is in contact with the outer side surface 21221 of the first extension portion.

[0231] As Figures 19 - 30 shown, in some other embodiments, along the first direction X, the second extension portion 21122 extends from the wall body 21121 to contact the first surface 21211 of the cover body 2121, and the distance between the second extension portion 21122 and the first surface 21211 is 0.

[0232] Along the first direction X, the second extension portion 21122 extends from the wall body 21121 to the cover body 2121. When assembling the battery cell 20, the housing 211 and the end cover 212 can be positioned and fitted. The second extension portion 21122 extends from the wall body 21121 to the cover body 2121, and the second extension portion 21122 can also play a role in blocking the leakage of the battery cell 20 and improving the sealing performance of the battery cell 20.

[0233] As Figure 23 、 Figure 24 、 Figure 29 、 Figure 30 shown, in some embodiments, the second extension portion 21122 is welded to the cover body 2121 to form the second connection portion Q4.

[0234] The second extension portion 21122 and the cover body 2121 can be welded by laser welding or penetration welding to form the second connection portion Q4.

[0235] The first extension portion 2122 and the housing 211 are connected to form the first connection position. The second extension portion 21122 is welded to the cover body 2121 to form the second connection portion Q4. Then, at least two connection relationships can be formed between the housing 211 and the end cover 212, which is beneficial to improving the connection stability and sealing reliability between the end cover 212 and the housing 211.

[0236] The second extension portion 21122 is welded to the cover body 2121 to form the second connection portion Q4, which is beneficial to improving the connection stability between the end cover 212 and the housing 211 and is beneficial to improving the sealing performance between the end cover 212 and the housing 211.

[0237] Of course, in some other embodiments, along the first direction X, after the second extension portion 21122 extends to the cover body 2121, it may not be connected to the cover body 2121, but only in contact with the cover body 2121.

[0238] When the second extension portion 21122 extends from the wall body 21121 to the cover body 2121 along the first direction X, in the thickness direction of the side wall 2112, the first extension portion 2122 is located outside the second extension portion 21122, or the first extension portion 2122 is located inside the second extension portion 21122.

[0239] As Figures 21 - 24 shown, the first extension portion 2122 is located inside the second extension portion 21122. The outer side surface 21123 of the wall body is flush with the outer side surface 21124 of the second extension portion. The first surface 21211 includes a first region 21213 that protrudes from the outer side surface 21221 of the first extension portion. One end of the second extension portion 21122 facing away from the wall body 21121 extends to abut against the first region 21213. The outer side surface 21124 of the second extension portion is flush with the outer peripheral surface 21212 of the cover body. One end of the first extension portion 2122 facing away from the cover body 2121 abuts against one end of the wall body 21121 connected to the second extension portion 21122. The inner side surface 21222 of the first extension portion and the inner side surface 21125 of the wall body may be flush or not flush.

[0240] The first extension portion 2122 and the housing 211 may be welded in a region corresponding to the abutting position of the first extension portion 2122 and the wall body 21121 to form a first connection portion Q1. Of course, the first extension portion 2122 and the housing 211 may also be welded at other positions to form the first connection portion Q1. For example, the first connection position is formed in a region between one end of the wall body 21121 facing the first surface 21211 and the first surface 21211. The cover body 2121 and the second extension portion 21122 may be welded to form a second connection portion Q4.

[0241] As Figures 27 - 30 shown, the first extension portion 2122 is located outside the second extension portion 21122. The inner side surface 21125 of the wall body is flush with the inner side surface 21126 of the second extension portion. The first surface 21211 includes a second region 21214 that is located inside the first extension portion 2122 and outside the insulating member 25. One end of the second extension portion 21122 facing away from the wall body 21121 extends to abut against the second region 21214. The outer side surface 21221 of the first extension portion is flush with the outer side surface 21123 of the wall body. One end of the first extension portion 2122 facing away from the cover body 2121 abuts against one end of the wall body 21121 connected to the second extension portion 21122. The outer side surface 21124 of the second extension portion is in contact with the inner side surface 21222 of the first extension portion.

[0242] The first extension part 2122 and the housing 211 can be welded in a region corresponding to the abutting position of the first extension part 2122 and the wall body 21121 to form a first connection part Q1 (as Figure 24 , Figure 30 shown). Of course, the first extension part 2122 and the housing 211 can also be welded at other positions to form the first connection part Q1. For example, the first connection position is formed in the region between one end of the wall body 21121 facing the first surface 21211 and the first surface 21211. The cover body 2121 and the second extension part 21122 can be welded to form a second connection part Q4.

[0243] Along the thickness direction of the side wall 2112, the first extension part 2122 is located outside the second extension part 21122, or the first extension part 2122 is located inside the second extension part 21122. The first extension part 2122 and the second extension part 21122 can prevent the battery cell 20 from leaking, which is beneficial to improving the sealing performance of the battery cell 20.

[0244] As Figures 31 - 42 shown, in some embodiments, the first extension part 2122 includes a first part 21223 and a second part 21224. The first part 21223 is connected to the first surface 21211, and the second part 21224 is disposed at one end of the first part 21223 facing away from the first surface 21211. In the projection plane perpendicular to the thickness direction of the side wall 2112, the positive projection of the second extension part 21122 at least partially overlaps with the positive projection of the second part 21224.

[0245] Along the thickness direction of the side wall 2112, the thickness of the second part 21224 is less than the thickness of the first part 21223. As Figures 31 - 36 shown, the outer side surface of the second part 21224 can be flush with the outer side surface of the first part 21223. The outer side surfaces of the first part 21223 and the second part 21224 together form the outer side surface 21221 of the first extension part. The inner side surface of the first part 21223 is closer to the electrode assembly 22 than the inner side surface of the second part 21224. The inner side surface of the first part 21223 is the inner side surface 21222 of the first extension part. Or, as Figures 37 - 42 shown, the outer side surface of the second part 21224 is closer to the electrode assembly 22 than the outer side surface of the first part 21223. The outer side surface of the first part 21223 is the outer side surface 21221 of the first extension part. The inner side surface of the first part 21223 is flush with the inner side surface of the second part 21224. The inner side surfaces of the first part 21223 and the second part 21224 together form the inner side surface 21222 of the first extension part.

[0246] In the projection plane perpendicular to the thickness direction of the side wall 2112, the orthographic projection of the second extension portion 21122 and the orthographic projection of the second part 21224 of the first extension portion 2122 at least partially overlap. When assembling the housing 211 and the end cap 212, the first extension portion 2122 and the second extension portion 21122 can be used for positioning and cooperation, which facilitates the assembly of the battery cell 20 and also facilitates the connection between the first extension portion 2122 and the side wall 2112.

[0247] As Figures 33 - 36 shown, in some embodiments, along the thickness direction of the side wall 2112, the second part 21224 is located outside the second extension portion 21122.

[0248] As Figure 34 、 Figure 36 shown, the outer side surface of the second part 21224 is flush with the outer side surface 21123 of the wall body. One end of the second part 21224 facing away from the first part 21223 can be attached to the end face of the wall body 21121 where the second extension portion 21122 is connected. One end of the second extension portion 21122 facing away from the wall body 21121 extends to the end face where the first part 21223 is connected to the second part 21224. The outer side surface 21124 of the second extension portion is attached to the inner side surface of the second part 21224. The inner side surface of the first part 21223 can be flush with the inner side surface 21126 of the second extension portion.

[0249] Along the thickness direction of the side wall 2112, the second part 21224 being located outside the second extension portion 21122 is beneficial to improving the sealing performance of the battery cell 20.

[0250] As Figure 36 shown, in the embodiment where, along the thickness direction of the side wall 2112, the second part 21224 is located outside the second extension portion 21122, the second part 21224 and the wall body 21121 are welded to form a first connection portion Q1.

[0251] The welding of the second part 21224 and the wall body 21121 to form the first connection portion Q1 enables the welding to be performed outside the housing 211, making the welding more convenient. The welding of the second part 21224 and the wall body 21121 to form the first connection portion Q1 also makes the connection position of the first connection portion Q1 and the housing 211 farther from the side of the cover body 2121 facing away from the electrode assembly 22, making the battery cell 20 more resistant to external forces, thereby improving the reliability of the battery cell 20 and extending the service life of the battery cell 20.

[0252] As Figure 34 、 Figure 36As shown, in the embodiment where the second part 21224 is located outside the second extension part 21122 in the thickness direction of the side wall 2112, the second extension part 21122 abuts against one end of the first part 21223 facing away from the first surface 21211.

[0253] That is, the second extension part 21122 extends to the end face where the first part 21223 is connected to the second part 21224, and the end face of the second extension part 21122 facing away from the wall body 21121 fits with the end face where the first part 21223 is connected to the second part 21224.

[0254] The second extension part 21122 abuts against one end of the first part 21223 facing away from the first surface 21211. When assembling the battery cell 20, the second extension part 21122 can be used in cooperation with the first extension part 2122 for positioning, thus facilitating the assembly of the battery cell 20.

[0255] As Figure 40 、 Figure 42 shown, in some embodiments, in the thickness direction of the side wall 2112, the second part 21224 is located inside the second extension part 21122.

[0256] As Figure 40 、 Figure 42 shown, the outer side surface of the first part 21223 is flush with the outer side surface 21124 of the second extension part. One end of the second part 21224 facing away from the first part 21223 can fit with the end face of the wall body 21121 where the second extension part 21122 is connected. One end of the second extension part 21122 facing away from the wall body 21121 extends to the end face where the first part 21223 is connected to the second part 21224. The inner side surface 21126 of the second extension part fits with the outer side surface of the second part 21224. The inner side surface of the second part 21224 can be flush with the inner side surface 21126 of the second extension part.

[0257] In the thickness direction of the side wall 2112, the second part 21224 is located inside the second extension part 21122, and the second part 21224 can play a role in preventing the leakage of the battery cell 20, which is beneficial to improving the sealing performance of the battery cell 20.

[0258] As Figure 42 shown, in the embodiment where the second part 21224 is located inside the second extension part 21122 in the thickness direction of the side wall 2112, the second extension part 21122 and the first part 21223 are welded to form a first connection part Q1.

[0259] The second extension part 21122 and the first part 21223 are welded to form a first connection part Q1, so that the welding can be carried out outside the housing 211, making the welding more convenient and reducing the welding difficulty.

[0260] As Figure 40 、As Figure 42 shown, in the embodiment where the second part 21224 is located inside the second extension 21122 along the thickness direction of the side wall 2112, the second part 21224 abuts against one end of the wall body 21121 facing the cover body 2121.

[0261] That is, the second part 21224 extends to the end face where the wall body 21121 is connected to the second extension 21122, and the end face of the second part 21224 facing away from the first part 21223 fits with the end face where the wall body 21121 is connected to the second extension 21122.

[0262] The second part 21224 abuts against one end of the wall body 21121 facing the cover body 2121. When assembling the battery cell 20, it is convenient to achieve the positioning and fitting of the end cover 212 and the housing 211. The second part 21224 can also play a role in preventing the leakage of the battery cell 20, which is beneficial to improving the sealing performance of the battery cell 20.

[0263] As Figure 34 、 Figure 36 、 Figure 40 、 Figure 41 shown, in some embodiments, along the first direction X, the dimension of the first extension 2122 is H3, and H3 ≥ 2 mm.

[0264] Along the first direction X, the dimension of the first extension 2122 is the distance between the first surface 21211 and the end of the first extension 2122 farthest from the first surface 21211.

[0265] Exemplarily, along the first direction X, the dimension H3 of the first extension 2122 can be 2 mm, 4 mm, 6 mm, 8 mm, 10 mm, 12 mm, 14 mm, 16 mm, 18 mm, etc.

[0266] The dimension of the first extension 2122 along the first direction X is greater than or equal to 2 mm, so that the connection position of the first extension 2122 and the housing 211 can be farther from the side of the cover body 2121 away from the electrode assembly 22, making the battery cell 20 more resistant to external forces, thereby improving the reliability of the battery cell 20 and extending the service life of the battery cell 20.

[0267] In some embodiments, H3 ≤ 20 mm.

[0268] For example, along the first direction X, the dimension H3 of the first extension 2122 can be 3 mm, 5 mm, 7 mm, 9 mm, 11 mm, 13 mm, 15 mm, 19 mm, 20 mm, etc.

[0269] The dimension of the first extension part 2122 along the first direction X is less than or equal to 20 mm, which controls the dimension of the end cover 212 within a reasonable range and facilitates the processing of the end cover 212.

[0270] With reference to Figure 37 , Figure 38 , Figure 43 , in some embodiments, the end cover 212 includes a plurality of first extension parts 2122, and the plurality of first extension parts 2122 are connected end to end in sequence along the circumferential direction of the opening 2111.

[0271] The plurality of first extension parts 2122 of the end cover 212 are connected end to end in sequence along the circumferential direction of the opening 2111. The plurality of first extension parts 2122 form a closed-loop structure along the circumferential direction of the opening 2111, and the cover body 2121 and the plurality of first extension parts 2122 jointly define an accommodation cavity.

[0272] If the plurality of first extension parts 2122 of the end cover 212 are connected end to end in sequence along the circumferential direction of the opening 2111, then the housing 211 and the first extension parts 2122 can be connected along the circumferential direction of the opening 2111, which is beneficial to improving the connection stability between the end cover 212 and the housing 211. If the housing 211 and the plurality of first extension parts 2122 are welded along the circumferential direction of the opening 2111, it not only makes the connection stability between the housing 211 and the end cover 212 better, but also makes the sealing performance between the end cover 212 and the housing 211 better. The plurality of first extension parts 2122 of the end cover 212 are connected end to end in sequence along the circumferential direction of the opening 2111, and also enables the plurality of first extension parts 2122 and the cover body 2121 to jointly form an accommodation cavity, which is beneficial to the end cover 212 and the housing 211 to form a larger accommodation space, so that more electrolyte can be accommodated inside the battery cell 20, which is beneficial to improving the cycling performance of the battery cell 20.

[0273] With reference to Figure 37 , Figure 38 , Figure 43 , in some embodiments, the end cover 212 includes two first extension parts 2122 arranged oppositely along the second direction Y and two first extension parts 2122 arranged oppositely along the third direction Z, and the first direction X, the second direction Y and the third direction Z are perpendicular to each other in pairs.

[0274] The two first extension parts 2122 in the second direction Y and the two first extension parts 2122 in the third direction Z are connected end to end in sequence along the circumferential direction of the opening 2111 to form a closed-loop structure. The two first extension parts 2122 in the second direction Y, the two first extension parts 2122 in the third direction Z and the cover body 2121 jointly form an accommodation cavity, which is beneficial to the end cover 212 and the housing 211 to form a larger accommodation space, so that more electrolyte can be accommodated inside the battery cell 20, which is beneficial to improving the cycling performance of the battery cell 20.

[0275] The end cover 212 is provided with two opposite first extension parts 2122 in the second direction Y and the third direction Z respectively, so that the end cover 212 and the housing 211 can be connected at multiple positions, which is beneficial to improving the connection stability between the end cover 212 and the housing 211.

[0276] The embodiment of the present application further provides a battery device 100, and the battery device 100 includes the battery cell 20 provided in any of the above embodiments.

[0277] The end cover 212 of the battery cell 20 provided in any of the above embodiments is formed with a first extension part 2122 extending towards the electrode assembly 22. By connecting the first extension part 2122 and the housing 211, the connection position between the end cover 212 and the housing 211 is farther from the side of the cover body 2121 of the end cover 212 facing away from the electrode assembly 22, so that the battery cell 20 has stronger ability to resist external forces, thereby improving the reliability of the battery cell 20 and extending the service life of the battery cell 20. The battery device 100 including the battery cell 20 also has better reliability and a longer service life.

[0278] The embodiment of the present application further provides an electrical device, and the electrical device includes the battery cell 20 provided in any of the above embodiments.

[0279] The end cover 212 of the battery cell 20 provided in any of the above embodiments is formed with a first extension part 2122 extending towards the electrode assembly 22. By connecting the first extension part 2122 and the housing 211, the connection position between the end cover 212 and the housing 211 is farther from the side of the cover body 2121 of the end cover 212 facing away from the electrode assembly 22, so that the battery cell 20 has stronger ability to resist external forces, thereby improving the reliability of the battery cell 20 and extending the service life of the battery cell 20. The electrical device powered by the battery cell 20 has better electrical reliability.

[0280] An embodiment of the present application provides a battery cell 20. The battery cell 20 is a prismatic battery. The battery cell 20 includes a housing 211, an electrode assembly 22, an end cap 212, and an insulating member 25. The housing 211 has an opening 2111 formed at one end along a first direction X, and the end cap 212 covers the opening 2111. The end cap 212 includes a cover body 2121 and a plurality of first extensions 2122, which are connected end to end along the circumference of the opening 2111. The cover body 2121 has a first surface 21211 facing the electrode assembly 22. The first extensions 2122 are connected to the first surface 21211 and extend in a direction toward the electrode assembly 22 in the first direction X. The first extensions 2122 are welded to the housing 211 to form a first connection portion Q1. Along the first direction X, the first connection portion Q1 is located on the side of the first surface 21211 facing the electrode assembly 22. The insulating member 25 includes an insulating body 252 and two abutting portions 253. The two abutting portions 253 are arranged at intervals along the second direction Y. The abutting portions 253 protrude from the surface of the insulating body 252 facing the electrode assembly 22. One end of the abutting portion 253 away from the insulating body 252 forms a abutting surface 251 and abuts against the electrode assembly 22. Along the first direction X, the abutting surface 251 is closer to the first surface 21211 than the first connecting portion Q1.

[0281] An embodiment of the present application provides a battery cell 20. The battery cell 20 is a prismatic battery. The battery cell 20 includes a housing 211, an electrode assembly 22, an end cap 212, and an insulating member 25. The housing 211 has an opening 2111 formed at one end along a first direction X, and the end cap 212 covers the opening 2111. The end cap 212 includes a cover body 2121 and four first extensions 2122, which are connected end to end along the circumference of the opening 2111. The cover body 2121 has a first surface 21211 facing the electrode assembly 22. The first extensions 2122 are connected to the first surface 21211 and extend in a direction toward the electrode assembly 22 in the first direction X. The first extensions 2122 are welded to the housing 211 to form a first connection portion Q1. Along the first direction X, the first connection portion Q1 is located on the side of the first surface 21211 facing the electrode assembly 22. Along the second direction Y, the insulating member 25 has a second surface 254 facing the first extension portion 2122, and the second surface 254 is provided with an avoidance groove Q2, which extends to the two surfaces of the insulating member 25 along the third direction Z. The avoidance groove Q2 extends to the abutment surface 251, and the projection of the first connecting portion Q1 along the second direction Y is at least partially located in the avoidance groove Q2, and the second direction Y is perpendicular to the first direction X.

[0282] An embodiment of the present application provides a battery cell 20, which is a square shell battery. The battery cell 20 includes a housing 211, an electrode assembly 22, an end cap 212, and an insulating member 25. An opening 2111 is formed at one end of the housing 211 along the first direction X, and the end cap 212 covers the opening 2111. The end cap 212 includes a cap body 2121 and four first extension portions 2122, and the plurality of first extension portions 2122 are sequentially connected end to end along the circumference of the opening 2111. The cap body 2121 has a first surface 21211 facing the electrode assembly 22. The first extension portion 2122 is connected to the first surface 21211 and extends in the first direction X towards the electrode assembly 22. The first extension portion 2122 is welded to the housing 211 to form a first connection portion Q1. Along the first direction X, the first connection portion Q1 is located on the side of the first surface 21211 facing the electrode assembly 22. The housing 211 includes a side wall 2112, and the side wall 2112 is provided corresponding to the first extension portion 2122 one by one. The side wall 2112 includes a wall body 21121 and a second extension portion 21122. The second extension portion 21122 is provided at one end of the wall body 21121 facing the cap body 2121 along the first direction X. In the projection plane perpendicular to the thickness direction of the side wall 2112, the orthographic projection of the second extension portion 21122 at least partially overlaps with the orthographic projection of the first extension portion 2122. Along the first direction X, the second extension portion 21122 extends from the wall body 21121 to the cap body 2121 and is welded to the cap body 2121 to form a second connection portion Q4. Along the thickness direction of the side wall 2112, the first extension portion 2122 is located outside the second extension portion 21122, or the first extension portion 2122 is located inside the second extension portion 21122.

[0283] An embodiment of the present application provides a battery cell 20, the battery cell 20 is a square-shell battery, and the battery cell 20 includes a housing 211, an electrode assembly 22, an end cap 212, and an insulating member 25. An opening 2111 is formed at one end of the housing 211 along the first direction X, and the end cap 212 covers the opening 2111. The end cap 212 includes a cap body 2121 and four first extension portions 2122, and the plurality of first extension portions 2122 are sequentially connected end to end along the circumference of the opening 2111. The cap body 2121 has a first surface 21211 facing the electrode assembly 22, and the first extension portion 2122 is connected to the first surface 21211 and extends in the first direction X towards the direction close to the electrode assembly 22. The first extension portion 2122 is welded to the housing 211 to form a first connection portion Q1. Along the first direction X, the first connection portion Q1 is located on the side of the first surface 21211 facing the electrode assembly 22. The first extension portion 2122 includes a first part 21223 and a second part 21224. The first part 21223 is connected to the first surface 21211, and the second part 21224 is provided at one end of the first part 21223 facing away from the first surface 21211. In the projection plane perpendicular to the thickness direction of the side wall 2112, the positive projection of the second extension portion 21122 at least partially overlaps with the positive projection of the second part 21224. The second extension portion 21122 abuts against one end of the first part 21223 facing away from the first surface 21211. One end of the second part 21224 facing away from the first part 21223 abuts against one end of the wall body 21121 facing the cap body 2121. Along the thickness direction of the side wall 2112, the second part 21224 is located outside the second extension portion 21122, and the second part 21224 is welded to the avoidance body to form the first connection portion Q1.

[0284] An embodiment of the present application provides a battery cell 20. The battery cell 20 is a square-shell battery, and the battery cell 20 includes a housing 211, an electrode assembly 22, an end cap 212, and an insulating member 25. An opening 2111 is formed at one end of the housing 211 along the first direction X, and the end cap 212 covers the opening 2111. The end cap 212 includes a cap body 2121 and four first extension portions 2122. The plurality of first extension portions 2122 are sequentially connected end to end along the circumference of the opening 2111. The cap body 2121 has a first surface 21211 facing the electrode assembly 22. The first extension portion 2122 is connected to the first surface 21211 and extends in the first direction X towards the electrode assembly 22. The first extension portion 2122 is welded to the housing 211 to form a first connection portion Q1. Along the first direction X, the first connection portion Q1 is located on the side of the first surface 21211 facing the electrode assembly 22. The first extension portion 2122 includes a first part 21223 and a second part 21224. The first part 21223 is connected to the first surface 21211, and the second part 21224 is disposed at one end of the first part 21223 facing away from the first surface 21211. In the projection plane perpendicular to the thickness direction of the side wall 2112, the orthographic projection of the second extension portion 21122 at least partially overlaps with the orthographic projection of the second part 21224. The second part 21224 abuts against one end of the wall body 21121 facing the cap body 2121. The second extension portion 21122 abuts against one end of the first part 21223 facing away from the cap body 2121. Along the thickness direction of the side wall 2112, the second part 21224 is located inside the second extension portion 21122, and the second extension portion 21122 is welded to the first part 21223 to form the first connection portion Q1.

[0285] It should be noted that, without conflict, the embodiments and features in the embodiments of the present application can be combined with each other.

[0286] The above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A battery cell, characterized in that, include: The housing is formed with an opening at at least one end along the first direction; an electrode assembly, at least partially housed within the housing; An end cover is covered on the opening, and the end cover includes a cover body and a first extension portion, the cover body has a first surface facing the electrode assembly, the first extension portion is connected to the first surface and extends in the first direction toward the electrode assembly, and the first extension portion is connected to the shell.

2. The battery cell according to claim 1, wherein, The first extension portion is welded to the shell to form a first connection portion. Along the first direction, the first connection portion is located on a side of the first surface facing the electrode assembly.

3. The battery cell according to claim 1, characterized in that, The electrode assembly includes a main body and a tab, wherein the tab protrudes from the main body, and the battery cell further includes an insulating member, wherein at least a portion of the insulating member is disposed between the cover body and the main body; Along the first direction, the insulating member has a contact surface, and the contact surface contacts the main body.

4. The battery cell according to claim 3, wherein, The insulating part includes an insulating body and a supporting portion, the supporting portion protrudes from the surface of the insulating body facing the electrode assembly, the supporting surface is formed at one end of the supporting portion facing away from the insulating body, and in a projection plane perpendicular to a second direction, the orthographic projection of the supporting portion at least partially overlaps with the orthographic projection of the electrode ear, and the second direction is perpendicular to the first direction.

5. The battery cell according to claim 4, wherein, The insulating member includes two abutting portions, which are spaced apart along the second direction. The first extending portions are provided on two opposite sides of the insulating member along the second direction.

6. The battery cell according to claim 4, wherein Along the first direction, a distance between the surface of the insulating body facing the first surface and the abutting surface is H1, and H1≤20 mm.

7. The battery cell according to claim 3, characterized in that, The first extension portion is welded to the shell to form a first connection portion. Along the first direction, the first connection portion is located on the side of the first surface facing the electrode assembly, and the abutting surface is closer to the first surface than the first connection portion.

8. The battery cell according to claim 3, characterized in that, The first extension portion is welded to the shell to form a first connection portion, and along the first direction, the first connection portion is located on a side of the first surface facing the electrode assembly; Along the second direction, the insulating member has a second surface facing the first extension portion, the second surface is provided with an avoidance groove, the projection of the first connecting portion along the second direction is at least partially located in the avoidance groove, and the second direction is perpendicular to the first direction.

9. The battery cell according to claim 8, wherein, Along the third direction, the avoidance groove extends to two opposite surfaces of the insulating member, and the first direction and the second direction are both perpendicular to the third direction.

10. The battery cell according to claim 9, wherein, The avoidance groove extends along the first direction to the abutting surface.

11. The battery cell according to claim 8, characterized in that, Along the second direction, a gap is formed between the second surface and the first extension portion.

12. The battery cell according to claim 11, characterized in that, Along the second direction, the size of the gap is H2, 0.1 mm ≤ H2 ≤ 20 mm.

13. The battery cell according to any one of claims 1-12, characterized in that, The housing includes side walls, which are arranged in one-to-one correspondence with the first extension parts. The side walls include wall bodies and second extension parts. The second extension parts are arranged at one end of the wall bodies facing the cover body along the first direction. In a projection plane perpendicular to the thickness direction of the side walls, the orthographic projection of the second extension parts at least partially overlaps with the orthographic projection of the first extension parts.

14. The battery cell according to claim 13, characterized in that, Along the first direction, the second extension parts extend from the wall bodies to the cover body.

15. The battery cell according to claim 14, wherein, The second extension parts are welded to the cover body to form second connection parts.

16. The battery cell according to claim 14 or 15, characterized in that, Along the thickness direction of the side walls, the first extension parts are located outside the second extension parts, or the first extension parts are located inside the second extension parts.

17. The battery cell according to claim 14 or 15, characterized in that, The first extension parts include a first part and a second part. The first part is connected to the first surface, and the second part is arranged at one end of the first part facing away from the first surface. In a projection plane perpendicular to the thickness direction of the side walls, the orthographic projection of the second extension parts at least partially overlaps with the orthographic projection of the second part.

18. The battery cell according to claim 17, wherein, Along the thickness direction of the side walls, the second part is located outside the second extension parts.

19. The battery cell according to claim 18, characterized in that, The second part is welded to the wall body to form a first connection part.

20. The battery cell according to claim 18 or 19, characterized in that, The second extension parts abut against one end of the first part facing away from the first surface.

21. The battery cell according to claim 17, characterized in that, Along the thickness direction of the side walls, the second part is located inside the second extension parts.

22. The battery cell according to claim 21, wherein, The second extension parts are welded to the first part to form a first connection part.

23. The battery cell according to claim 21 or 22, characterized in that, The second part abuts against one end of the wall body facing the cover body.

24. The battery cell according to any one of claims 1-12, characterized in that, Along the first direction, the size of the first extension parts is H3, and H3≥2mm.

25. The battery cell according to claim 24, wherein, H3≤20mm.

26. The battery cell according to any one of claims 1-2, characterized in that, The end cover includes a plurality of the first extension parts, and the plurality of the first extension parts are connected end to end in sequence along the circumference of the opening.

27. The battery cell according to claim 26, wherein The end cover includes two first extension parts arranged opposite to each other along a second direction and two first extension parts arranged opposite to each other along a third direction. The first direction, the second direction, and the third direction are perpendicular to each other in pairs.

28. A battery device, characterized in that, Including the battery cell according to any one of claims 1-27.

29. An electrical device, characterized in that, Including the battery cell according to any one of claims 1-27.

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