Battery cell, battery, and electric device

Abstract

A battery cell (20), a battery, and an electric device, relating to the technical field of batteries. The battery cell (20) comprises a casing (21), an electrode assembly (22), and an end cover (23). An opening (211) is formed in at least one end of the casing (21) in a first direction. The electrode assembly (22) is accommodated in the casing (21). The end cover (23) seals the opening (211). The inner surface of the casing (21) comprises a first inner circumferential surface (2141a) and a blocking surface (2142a) which are arranged in the first direction and connected; the end of the first inner circumferential surface (2141a) away from the blocking surface (2142a) defines the opening (211); the first inner circumferential surface (2141a) is welded to an outer circumferential surface (231) of the end cover (23) to form a weld mark (24); and in the first direction, at least part of the projection of the weld mark (24) is located within the blocking surface (2142a). Thus, a welding seam between the outer circumferential surface of the end cover (23) and the first inner circumferential surface (2141a) is at least partially blocked by the blocking surface (2142a) in the first direction, so as to ameliorate the situation that a light beam or heat generated when the outer circumferential surface (231) of the end cover (23) and the first inner circumferential surface (2141a) are welded acts directly on the electrode assembly (22), thereby reducing the situation that the electrode assembly (22) accommodated in the casing is burnt when the end cover (23) and the casing (21) are welded to each other.

Description

Battery cells, batteries and electrical devices

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 2024206871096, filed on April 3, 2024, entitled “Battery Cell, Battery and Electrical Device,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of battery technology, and in particular to a battery cell, a battery, and an electrical device. Background Art

[0004] New energy vehicles have experienced rapid development. In the electric vehicle sector, power batteries, as the power source of electric vehicles, play an irreplaceable and important role. With the vigorous promotion of new energy vehicles, the demand for power battery products is also growing. Among them, batteries, as core components of new energy vehicles, have high requirements in terms of performance and production quality.

[0005] In battery technology, a battery cell includes an outer shell and an electrode assembly housed therein. The outer shell includes an end cap and a shell. To improve the reliability and stability of the connection between the end cap and the shell, the end cap is usually welded to the shell. However, in existing battery cells, the electrode assembly is easily damaged during the assembly process of the end cap and the shell, resulting in poor production quality of the battery cell.

[0006] Summary of the Invention

[0007] The embodiments of the present application provide a battery cell, a battery, and an electrical device, which can effectively improve the production quality of the battery cell.

[0008] 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 in a first direction; the electrode assembly is accommodated in the shell; and the end cover closes the opening; wherein the inner surface of the shell comprises a first inner circumferential surface and a blocking surface arranged and connected along the first direction, the first inner circumferential surface enclosing an end away from the blocking surface to form the opening, the first inner circumferential surface is welded to the outer circumferential surface of the end cover to form a weld mark, and along the first direction, at least part of the projection of the weld mark is located within the blocking surface.

[0009] In the above technical solution, the inner surface of the shell includes a first inner circumferential surface and a blocking surface which are arranged in sequence and connected along a first direction, and the first inner circumferential surface is enclosed at one end away from the blocking surface to form an opening. The outer circumferential surface of the end cap and the first inner circumferential surface of the shell are welded to each other to form a weld mark, and at least part of the projection of the weld mark in the first direction is set to be located within the blocking surface, so that the blocking surface is an inclined surface or an arc surface connected to the first inner circumferential surface and inclined or bent from the first inner circumferential surface toward the direction close to the electrode assembly, so that the end of the shell with the opening has an enlarged inner diameter. The battery cell adopting this structure makes it easy to insert the end cap into the shell from the opening of the shell, so that the outer circumferential surface of the end cap is welded to the first inner circumferential surface, and the outer circumferential surface of the end cap and the shell can be welded from the side of the end cap away from the electrode assembly. The first inner circumference of the shell is welded to the first inner circumference, which is beneficial to reducing the difficulty of welding, improving the welding quality and welding efficiency, thereby improving the production efficiency of the battery cell. On the other hand, the welding gap between the outer circumference of the end cover and the first inner circumference of the shell can be at least partially blocked by the blocking surface in the first direction, so that the light beam or heat generated when welding the outer circumference of the end cover and the first inner circumference of the shell can be blocked by the blocking surface, thereby alleviating the phenomenon that the light beam or heat generated when welding the outer circumference of the end cover and the first inner circumference of the shell directly acts on the electrode assembly, thereby reducing the phenomenon that the electrode assembly contained in the shell is burned when the end cover and the shell are welded to each other, and further effectively reducing the phenomenon that the battery cell damages the electrode assembly during the assembly process, thereby improving the production quality of the battery cell.

[0010] In some embodiments, the blocking surface is an annular structure extending along the circumference of the first inner circumferential surface.

[0011] In the above technical solution, by setting the blocking surface as an annular structure extending along the circumference of the first inner circumferential surface, the blocking surface can block the welding gap between the outer circumferential surface of the end cover and the first inner circumferential surface of the shell along the first direction over the entire circumference of the first inner circumferential surface, thereby improving the blocking effect of the blocking surface on the light beam or heat generated by the welding when the outer circumferential surface of the end cover and the first inner circumferential surface of the shell are welded together, thereby further reducing the phenomenon of burning the electrode assembly when the end cover and the shell are welded to each other, thereby further improving the production quality of the battery cell.

[0012] In some embodiments, along the first direction, the size of the first inner circumferential surface is D1, satisfying 0.2 mm ≤ D1 ≤ 3.2 mm.

[0013] In the above technical solution, the size of the first inner circumferential surface in the first direction is 0.2 mm to 3.2 mm. On the one hand, by setting the size of the first inner circumferential surface in the first direction to be greater than or equal to 0.2 mm, the area of ​​the region where the shell and the end cover are welded to each other is increased, which is beneficial to improving the welding firmness between the shell and the end cover, so as to improve the assembly quality of the battery cell and reduce the difficulty of welding between the outer circumferential surface of the end cover and the first inner circumferential surface of the shell. On the other hand, by setting the size of the first inner circumferential surface in the first direction to be less than or equal to 3.2 mm, the phenomenon of excessive space occupied by the first inner circumferential surface and waste of the internal space of the shell is alleviated, which is beneficial to improving the internal space utilization rate of the battery cell.

[0014] In some embodiments, the inner surface of the shell also includes a second inner circumferential surface, the first inner circumferential surface, the blocking surface and the second inner circumferential surface are arranged along the first direction, and the blocking surface connects the first inner circumferential surface and the second inner circumferential surface; wherein the projection of the second inner circumferential surface in the first direction is located on the inner side of the first inner circumferential surface.

[0015] In the above technical solution, the inner surface of the shell also includes a second inner circumferential surface, the blocking surface is connected between the first inner circumferential surface and the second inner circumferential surface, and the projection of the second inner circumferential surface in the first direction is located on the inner side of the first inner circumferential surface, so that the inner diameter of the second inner circumferential surface is smaller than the inner diameter of the first inner circumferential surface, so as to form a blocking surface between the first inner circumferential surface and the second inner circumferential surface that is inclined or curved toward the direction of the electrode assembly, thereby reducing the difficulty of forming the blocking surface on the inner surface of the shell, which is beneficial to reducing the manufacturing difficulty of the battery cell and improving the production efficiency of the battery cell.

[0016] In some embodiments, the first inner circumferential surface is parallel to the second inner circumferential surface.

[0017] In the above technical solution, by setting the first inner circumferential surface and the second inner circumferential surface to be parallel to each other, so that the first inner circumferential surface is surrounded by the outside of the second inner circumferential surface and the distance between the first inner circumferential surface and the second inner circumferential surface at any position along the radial direction of the first inner circumferential surface is equal, the regularity of the shape of the shell can be improved, and the electrode assembly can be easily assembled into the shell, which is beneficial to reduce the difficulty of assembling the battery cell.

[0018] In some embodiments, along the radial direction of the first inner circumferential surface, a minimum distance between the first inner circumferential surface and the second inner circumferential surface is D2, satisfying 0.1 mm ≤ D2 ≤ 1.2 mm.

[0019] In the above technical solution, the radial spacing between the first inner circumference and the second inner circumference is 0.1mm to 1.2mm. On the one hand, the radial spacing between the first inner circumference and the second inner circumference is set to be greater than or equal to 0.1mm to alleviate the phenomenon that the area of ​​the blocking surface formed between the first inner circumference and the second inner circumference is too small, thereby improving the blocking effect of the blocking surface on the light beam or heat generated by welding when the outer circumference of the end cover is welded to the first inner circumference of the shell, and reducing the difficulty of forming a blocking surface between the first inner circumference and the second inner circumference. On the other hand, the radial spacing between the first inner circumference and the second inner circumference is set to be less than or equal to 1.2mm to alleviate the phenomenon that the area where the first inner circumference of the shell is formed is excessively thinned or expanded, thereby reducing the processing difficulty of the shell, making it easier to form and manufacture, and reducing the phenomenon of excessive waste of internal space of the shell.

[0020] In some embodiments, the shell includes a side wall; the side wall surrounds the outside of the electrode assembly, and the opening is formed on at least one end of the side wall in the first direction. The side wall includes a first side wall, a connecting wall, and a second side wall arranged in sequence and connected along the first direction, the inner surface of the first side wall is the first inner circumferential surface, the inner surface of the connecting wall is the blocking surface, and the inner surface of the second side wall is the second inner circumferential surface; wherein, along the first direction, the projection of the outer circumferential surface of the second side wall is located on the inner side of the outer circumferential surface of the first side wall.

[0021] In the above technical solution, the first inner circumferential surface, the blocking surface and the second inner circumferential surface of the shell are respectively the first side wall, the connecting wall and the inner surface of the second side wall facing the electrode assembly. By setting the projection of the outer circumferential surface of the second side wall in the first direction to be located on the inner side of the outer circumferential surface of the first side wall, the first side wall of the shell is a structure that extends outward in the radial direction of the first inner circumferential surface compared to the second side wall, and the connecting wall is a curved or inclined structure connected between the first side wall and the second side wall, so as to realize the formation of the first inner circumferential surface, the blocking surface and the second inner circumferential surface on the inner surface of the side wall. The structure is simple and easy to implement, which is conducive to reducing the processing difficulty of the shell of the battery cell.

[0022] In some embodiments, a wall thickness of the first sidewall is smaller than a wall thickness of the second sidewall.

[0023] In the above technical solution, by setting the wall thickness of the first side wall to be smaller than the wall thickness of the second side wall, the radial distance between the first inner circumference and the second inner circumference of the first inner circumference is kept constant, and the radial outward expansion size of the first side wall compared to the second side wall of the first inner circumference can be effectively reduced, thereby facilitating the reduction of the size difference on the outer circumference of the shell, and reducing the interference between the battery cells and the space occupied by the battery cells during the subsequent assembly of the battery cells into groups.

[0024] In some embodiments, the wall thickness of the first sidewall is D3, and the wall thickness of the second sidewall is D4, satisfying 1>D3 / D4≥0.55.

[0025] In the above technical solution, by setting the wall thickness of the first side wall to be greater than or equal to 0.55 times the wall thickness of the second side wall, the phenomenon of transitional thinning of the first side wall is alleviated, thereby reducing the outward expansion size of the first side wall compared to the second side wall while improving the structural strength of the first side wall, thereby reducing the deformation or damage of the first side wall during use, and improving the welding quality between the first inner peripheral surface of the first side wall and the outer peripheral surface of the end cover.

[0026] In some embodiments, the shell includes a side wall; the side wall surrounds the outside of the electrode assembly, and the opening is formed on at least one end of the side wall in the first direction. The side wall includes a first side wall, a connecting wall, and a second side wall arranged in sequence and connected along the first direction, the inner surface of the first side wall is the first inner circumferential surface, the inner surface of the connecting wall is the blocking surface, and the inner surface of the second side wall is the second inner circumferential surface; wherein the outer circumferential surface of the second side wall is coplanar with the outer circumferential surface of the first side wall.

[0027] In the above technical solution, the first inner circumferential surface, the blocking surface and the second inner circumferential surface of the shell are respectively the first side wall, the connecting wall and the inner surface of the second side wall facing the electrode assembly. By setting the outer circumferential surface of the second side wall and the outer circumferential surface of the first side wall to a coplanar structure, that is, the outer circumferential surface of the second side wall is flush with the outer circumferential surface of the first side wall, the first side wall is made to be thinner than the second side wall, so as to form a blocking surface between the first inner circumferential surface and the second inner circumferential surface. The battery cell adopting this structure can form a blocking surface on the inner surface of the side wall while improving the consistency of the outer circumferential surface of the shell, thereby reducing the size difference of the outer circumferential surface of the shell, and reducing the interference between the battery cells and the space occupied by the battery cells during the subsequent assembly of the battery cells into groups.

[0028] In some embodiments, along the first direction, the end cap abuts against the blocking surface.

[0029] In the above technical solution, by setting the end cover to abut against the blocking surface along the first direction, the blocking surface can also be used for the end cover to abut in the first direction. On the one hand, the battery cell adopting this structure can also play a certain positioning and limiting role on the end cover through the blocking surface, so as to alleviate the phenomenon of excessive insertion of the end cover in the accommodating cavity, which is beneficial to improving the assembly accuracy and assembly quality between the end cover and the shell, so as to improve the production quality of the battery cell. On the other hand, it can achieve at least partial mutual fit between the blocking surface and the end cover, so as to further enhance the effect of the blocking surface in shielding the welding gap between the outer peripheral surface of the end cover and the first inner peripheral surface of the shell, so as to further enhance the blocking effect of the blocking surface on the light beam or heat generated by welding when the outer peripheral surface of the end cover is welded to the first inner peripheral surface of the shell, so as to further reduce the phenomenon of burning the electrode assembly when the end cover and the shell are welded to each other, which can be beneficial to improving the production quality of the battery cell.

[0030] In some embodiments, the end cap has a first surface facing the electrode assembly in the first direction, the first surface is connected to the outer peripheral surface of the end cap via a transition surface, and the transition surface abuts against the blocking surface.

[0031] In the above technical solution, a transition surface is formed between the first surface of the end cover and the outer peripheral surface of the end cover, and the end cover is a structure in which the transition surface and the blocking surface abut each other, so that on the one hand, the fitting effect between the end cover and the blocking surface can be improved, so as to further improve the effect of the blocking surface in blocking the welding gap between the outer peripheral surface of the end cover and the first inner peripheral surface of the shell, and the positioning and limiting effect of the blocking surface on the end cover can be improved. On the other hand, the transition surface can also play a certain guiding role when the end cover is assembled in the shell, so that at least part of the end cover can be inserted into the shell from the opening of the shell, which is conducive to reducing the difficulty of assembly between the end cover and the shell.

[0032] In some embodiments, the transition surface includes a first rounded surface, and the blocking surface includes a second rounded surface, and the second rounded surface fits with the first rounded surface and adheres to each other.

[0033] In the above technical solution, the transition surface is formed with a first rounded corner, the blocking surface is formed with a second rounded corner surface, and the second rounded corner surface fits with the first rounded corner surface and fits with each other, so that at least part of the transition surface fits with at least part of the blocking surface and fits with each other, thereby further improving the fitting effect between the end cover and the blocking surface, and further improving the effect of the blocking surface in covering the welding gap between the outer peripheral surface of the end cover and the first inner peripheral surface of the shell, and further improving the positioning and limiting effect of the blocking surface on the end cover.

[0034] In some embodiments, the end of the shell forming the opening in the first direction has a first end surface, the first end surface is connected to the first inner circumferential surface, and the end cover has a second surface facing away from the electrode assembly in the first direction, the second surface is connected to the outer circumferential surface of the end cover, and the second surface is coplanar with the first end surface.

[0035] In the above technical solution, the first end surface of the shell connected to the first inner circumferential surface and the second surface of the end cover facing away from the electrode assembly and connected to the outer circumferential surface of the end cover are set to a coplanar structure, so that the first end surface of the shell and the second surface of the end cover are flush structures, which is beneficial to reducing the difficulty of welding between the first inner circumferential surface of the shell and the outer circumferential surface of the end cover, and is beneficial to improving the welding quality between the first inner circumferential surface of the shell and the outer circumferential surface of the end cover.

[0036] In some embodiments, along the first direction, the end cap has a third surface farthest from the electrode assembly, and the third surface is farther from the electrode assembly than the second surface.

[0037] In the above technical solution, a third surface is formed on the side of the end cover facing away from the electrode assembly in the first direction, and the third surface is farther away from the electrode assembly than the second surface. Therefore, on the one hand, the support and blocking of the third surface can play a certain protective role on the weld mark between the first inner peripheral surface of the shell and the outer peripheral surface of the end cover, so as to alleviate the wear of the weld mark, thereby improving the connection reliability between the end cover and the shell, which is beneficial to reducing the risk of connection failure between the end cover and the shell. On the other hand, it can reduce the influence of the weld mark protruding from the second surface of the end cover on the height dimension of the battery cell in the first direction, which is beneficial to reducing the difficulty of subsequent assembly of the battery cell into groups, and is beneficial to reducing the interference effect of the weld mark in the subsequent assembly of the battery cell into groups.

[0038] In some embodiments, the end cap is formed with a protrusion protruding from the second surface along the first direction, and a side of the protrusion facing away from the electrode assembly in the first direction forms the third surface.

[0039] In the above technical solution, a protrusion is formed on the side of the end cover away from the electrode assembly along the first direction, the protrusion protrudes from the second surface, and a third surface is formed on the side of the protrusion away from the electrode assembly in the first direction, so as to form a third surface on the end cover that is farther away from the electrode assembly than the second surface. The structure is simple and easy to implement.

[0040] In some embodiments, along the first direction, a distance D5 between the third surface and the second surface satisfies 0.1 mm ≤ D5 ≤ 0.6 mm.

[0041] In the above technical solution, the distance between the third surface and the second surface of the end cover is 0.1mm to 0.6mm. On the one hand, by setting the spacing between the third surface and the second surface to be greater than or equal to 0.1mm, the distance between the third surface and the second surface is increased, which is beneficial to improving the protection effect of the third surface on the weld mark, so as to alleviate the wear of the weld mark, and can further reduce the impact of the weld mark on the height dimension of the battery cell in the first direction, so as to reduce the difficulty of subsequent assembly of the battery cell and the interference risk caused by the weld mark in the subsequent assembly of the battery cell. On the other hand, by setting the spacing between the third surface and the second surface to be less than or equal to 0.6mm, the phenomenon that the third surface is too far away from the electrode assembly compared with the second surface is alleviated, which is beneficial to reducing the difficulty of forming the third surface of the end cover, and can save the space occupied by the battery cell in the first direction, so as to improve the space utilization of the battery cell.

[0042] In some embodiments, the end cap has a first surface facing the electrode assembly in the first direction; wherein, along the first direction, a first groove is formed on the first surface at a position corresponding to the protrusion.

[0043] In the above technical solution, a first groove is formed on the first surface of the end cover facing the electrode assembly and in the area corresponding to the protrusion, so that the protrusion of the end cover is a structure that can be formed by stamping, so as to form a protrusion and a first groove on both sides of the end cover along the first direction respectively, which is conducive to reducing the manufacturing difficulty of the end cover and improving the production efficiency of the end cover.

[0044] In some embodiments, the second surface is provided with a second groove, and the second groove is an annular groove extending along the circumference of the first inner circumferential surface.

[0045] In the above technical solution, a second groove is provided on the second surface, and the second groove is an annular structure extending along the circumference of the first inner circumferential surface, so that the first inner circumferential surface of the shell and the outer circumferential surface of the end cover are structures surrounding the outside of the second groove. The battery cell adopting this structure can absorb the stress generated by the welding connection between the first inner circumferential surface of the shell and the outer circumferential surface of the end cover through the second groove, so as to reduce the deformation or damage of the end cover caused by the welding stress, and can reduce the influence of the welding stress on other components on the end cover, thereby facilitating the improvement of the assembly quality of the battery cell.

[0046] In some embodiments, the shell is cylindrical, and the central axis of the shell extends along the first direction.

[0047] In the above technical solution, by setting the shell of the battery cell to a cylindrical shape, it is easy to process and form a battery cell with a cylindrical structure, so that the battery cell has the advantages of high capacity, long cycle life, and a wide range of operating ambient temperatures.

[0048] In some embodiments, the first inner circumferential surface is laser welded to the outer circumferential surface of the end cover.

[0049] In the above technical solution, laser welding is used to connect the first inner circumference of the shell and the outer circumference of the end cover. On the one hand, it can effectively improve the welding efficiency between the first inner circumference of the shell and the outer circumference of the end cover, so as to improve the assembly efficiency of the battery cell. On the other hand, it has higher safety in the process of welding the first inner circumference of the shell and the outer circumference of the end cover, and can reduce the welding deformation of the end cover and the shell.

[0050] In a second aspect, an embodiment of the present application further provides a battery comprising the above-mentioned battery cell.

[0051] In a third aspect, an embodiment of the present application further provides an electrical device, comprising the above-mentioned battery cell, wherein the battery cell is used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0053] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0054] FIG2 is an exploded view of the structure of a battery provided in some embodiments of the present application;

[0055] FIG3 is a schematic structural diagram of a battery cell provided in some embodiments of the present application;

[0056] FIG4 is an exploded view of the structure of a battery cell provided in some embodiments of the present application;

[0057] FIG5 is a cross-sectional view of a battery cell provided in some embodiments of the present application;

[0058] FIG6 is a partial enlarged view of the battery cell at point A shown in FIG5 ;

[0059] FIG7 is a partial cross-sectional view of a side wall of a housing provided in some embodiments of the present application;

[0060] FIG8 is a cross-sectional view of a battery cell provided in some other embodiments of the present application;

[0061] FIG9 is a partial enlarged view of a portion B of the battery cell shown in FIG8 .

[0062] Icon: 1000 - vehicle; 100 - battery; 10 - housing; 11 - first housing body; 12 - second housing body; 20 - battery cell; 21 - housing; 211 - opening; 212 - receiving chamber; 213 - bottom wall; 214 - side wall; 2141 - first side wall; 2141a - first inner circumference; 2141b - outer circumference of first side wall; 2142 - connecting wall; 2142a - blocking surface; 2143 - second side wall; 2143a - second inner circumference; 2143 b-outer circumference of the second side wall; 215-first end face; 22-electrode assembly; 221-ear; 23-end cover; 231-outer circumference of the end cover; 232-first surface; 233-transition surface; 234-second surface; 235-third surface; 236-protrusion; 237-first groove; 238-second groove; 24-weld mark; 25-electrode terminal; 26-current collecting member; 200-controller; 300-motor; X-first direction; Y-radial direction of the first inner circumference. DETAILED DESCRIPTION

[0063] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0064] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0065] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0066] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0067] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0068] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0069] The term "plurality" used in this application refers to two or more (including two).

[0070] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0071] The battery cells can be lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, etc., which are not limited in the embodiments of the present application.

[0072] A battery cell typically includes an electrode assembly. This assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of a battery cell, active ions (such as lithium ions) are inserted and removed between the positive and negative electrodes. The separator, placed between the positive and negative electrodes, prevents short circuits between the positive and negative electrodes while allowing the active ions to pass through.

[0073] 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 disposed on at least one surface of the positive electrode current collector.

[0074] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0075] 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. may be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum 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.).

[0076] 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 traditional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, examples of lithium-containing phosphates may include but are not limited to at least one of lithium iron phosphate (such as LiFePO4 (also referred to 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 iron manganese phosphate, and a composite material of lithium iron manganese 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 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05O2) and at least one of its modified compounds, etc.

[0077] In some embodiments, a positive electrode may utilize a metal foam. The metal foam may include nickel foam, copper foam, aluminum foam, alloy foam, or the like. When a metal foam is used as the positive electrode, the surface of the metal foam may or may not include a positive electrode active material. For example, a lithium source material, potassium metal, or sodium metal may be filled or / and deposited within the metal foam, where the lithium source material is lithium metal and / or a lithium-rich material.

[0078] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0079] As an example, the negative electrode current collector may be a metal foil, a metal foam, or a composite current collector. For example, as the metal foil, aluminum or stainless steel treated with silver, stainless steel, copper, aluminum, nickel, carbon electrode, nickel, or titanium, etc. may be used. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, etc. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (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.).

[0080] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0081] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is provided on either or both of the two facing surfaces of the negative electrode current collector.

[0082] As an example, the negative electrode active material may adopt the negative electrode active material for battery cells that is well known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0083] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0084] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0085] In some embodiments, the separator is a separator membrane. There are many types of separator membranes, and any known separator membrane with a porous structure having good chemical stability and mechanical stability can be selected.

[0086] As an example, the separator can be made of at least one of fiberglass, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film. In the case of a multi-layer composite film, the materials of each layer can be the same or different. The separator can be a separate component positioned between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes.

[0087] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transport ions and isolate the positive and negative electrodes.

[0088] In some embodiments, the battery cell further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel, or solid. Liquid electrolytes include an electrolyte salt and a solvent.

[0089] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium bisoxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0090] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl 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, cyclopentane, 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.

[0091] Among them, the gel electrolyte includes a skeleton network with a polymer as the electrolyte, combined with an ionic liquid-lithium salt.

[0092] Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0093] As an example, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a single ion polymer, polyionic liquid-lithium salt, cellulose, or the like.

[0094] As an example, the inorganic solid electrolyte may include an oxide solid electrolyte (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON film), a sulfide solid electrolyte (crystalline lithium superion conductor (lithium germanium phosphosulfide, silver germanium sulfide), amorphous sulfide) and one or more of a halide solid electrolyte, a nitride solid electrolyte and a hydride solid electrolyte.

[0095] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0096] In some embodiments, the electrode assembly is a wound structure, wherein the positive electrode sheet and the negative electrode sheet are wound into the wound structure.

[0097] In some embodiments, the electrode assembly is a laminate structure.

[0098] As an example, multiple positive electrode sheets and multiple negative electrode sheets can be provided respectively, and the multiple positive electrode sheets and the multiple negative electrode sheets can be alternately stacked.

[0099] As an example, a plurality of positive electrode sheets may be provided, and the negative electrode sheet may be folded to form a plurality of stacked folded segments, with a positive electrode sheet being sandwiched between adjacent folded segments.

[0100] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of stacked folded segments.

[0101] As an example, a plurality of separators may be provided, each of which is disposed between any adjacent positive electrode sheets or negative electrode sheets.

[0102] As an example, the separator may be provided continuously, and may be provided between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0103] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0104] In some embodiments, the electrode assembly is provided with tabs that can conduct current from the electrode assembly. The tabs include a positive tab and a negative tab.

[0105] In some embodiments, a 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 housing, an aluminum housing, a plastic housing (e.g., polypropylene), a composite metal housing (e.g., a copper-aluminum composite housing), or an aluminum-plastic film.

[0106] As an example, the battery cells may be cylindrical, prismatic, soft-pack or other shaped battery cells. Prismatic battery cells include but are not limited to square-shell, blade-shaped, and polygonal batteries, such as hexagonal batteries.

[0107] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0108] In some embodiments, the battery may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0109] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are housed in the case.

[0110] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0111] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0112] Batteries, with their outstanding advantages such as high energy density, low environmental pollution, high power density, long service life, wide adaptability, and low self-discharge coefficient, are a vital component of today's new energy development. The development of battery technology requires simultaneous consideration of multiple design factors, such as energy density, cycle life, discharge capacity, charge and discharge rate, and other performance parameters.

[0113] For a general battery cell, the battery cell includes an outer shell and an electrode assembly accommodated in the outer shell. The outer shell includes an end cap and a shell. The interior of the shell forms a accommodating cavity with an opening, and the end cap is covered at the opening to form an outer shell for accommodating the electrode assembly. In related technologies, in order to improve the connection reliability and stability between the end cap and the shell, laser welding is usually used to connect the end cap to the opening of the shell. However, in the process of connecting the end cap and the shell by laser welding, the laser can easily enter the interior of the shell through the gap between the end cap and the shell, thereby causing the electrode assembly to be burned by the laser, so that the electrode assembly is easily damaged during the mutual assembly of the end cap and the shell, which leads to poor production quality of the battery cell.

[0114] Based on the above considerations, in order to solve the problems of battery cells, an embodiment of the present application provides a battery cell, which includes a housing, an electrode assembly, and an end cap. The housing has an opening formed at at least one end in a first direction. The electrode assembly is accommodated in the housing. The end cap closes the opening. The inner surface of the housing includes a first inner circumferential surface and a blocking surface arranged and connected along the first direction. The end of the first inner circumferential surface away from the blocking surface encloses an opening. The first inner circumferential surface is welded to the outer circumferential surface of the end cap to form a weld mark. At least a portion of the projection of the weld mark along the first direction is located within the blocking surface.

[0115] In a battery cell of this structure, the inner surface of the shell includes a first inner circumferential surface and a blocking surface which are arranged in sequence and connected along a first direction, and the first inner circumferential surface is enclosed at one end away from the blocking surface to form an opening, and the outer circumferential surface of the end cap and the first inner circumferential surface of the shell are welded to each other to form a weld mark, and at least part of the projection of the weld mark in the first direction is set to be located within the blocking surface, so that the blocking surface is an inclined surface or arc surface connected to the first inner circumferential surface and inclined or curved from the first inner circumferential surface toward the direction close to the electrode assembly, so that the end of the shell with the opening has a structure with an enlarged inner diameter. The battery cell adopting this structure makes it easy to insert the end cap into the shell from the opening of the shell, so that the outer circumferential surface of the end cap is welded to the first inner circumferential surface, and the outer circumferential surface and the end cap can be welded from the side of the end cap away from the electrode assembly. Welding the first inner circumference of the shell is beneficial to reducing the difficulty of welding, thereby improving the welding quality and welding efficiency, thereby improving the production efficiency of the battery cell. On the other hand, it can achieve that the welding gap between the outer circumference of the end cover and the first inner circumference of the shell is at least partially blocked by the blocking surface in the first direction, so that the light beam or heat generated when welding the outer circumference of the end cover and the first inner circumference of the shell can be blocked by the blocking surface, thereby alleviating the phenomenon that the light beam or heat generated when welding the outer circumference of the end cover and the first inner circumference of the shell directly acts on the electrode assembly, thereby reducing the phenomenon of burning the electrode assembly contained in the shell when the end cover and the shell are welded to each other, and further effectively reducing the phenomenon of damaging the electrode assembly of the battery cell during the assembly process, thereby improving the production quality of the battery cell.

[0116] The battery cells disclosed in the embodiments of this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. A power supply system comprising the battery cells and batteries disclosed in this application can be used to construct such electrical devices. This can help alleviate problems such as improper or poorly accurate assembly of the battery cell housing and end caps, and can also help alleviate damage to the electrode assembly during assembly of the end cap and housing, thereby improving the production quality of the battery cells.

[0117] The present invention provides an electric device that uses a battery as a power source. The electric device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, etc. The electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0118] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device according to an embodiment of the present application.

[0119] Please refer to Figure 1, which is a structural schematic diagram of a vehicle 1000 provided in some embodiments of the present application. The vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000. The battery 100 can be arranged at the bottom of the vehicle 1000, or at the head of the vehicle 1000, or at the tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000. For example, the battery 100 can be used as an operating power source or a power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0120] In some embodiments of the present application, the battery 100 can not only serve as the operating power source or usage power source of the vehicle 1000, but also serve 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.

[0121] 2 and 3 , FIG2 is an exploded view of a battery 100 according to some embodiments of the present invention, and FIG3 is a schematic diagram of a battery cell 20 according to some embodiments of the present invention. The battery 100 includes a housing 10 and a battery cell 20 , wherein the battery cell 20 is accommodated in the housing 10 .

[0122] The housing 10 is used to provide assembly space for the battery cells 20 and can adopt a variety of structures. In some embodiments, the housing 10 can include a first housing body 11 and a second housing body 12. The first housing body 11 and the second housing body 12 cover each other, and the first housing body 11 and the second housing body 12 jointly define an assembly space for accommodating the battery cells 20. The second housing body 12 can be a hollow structure with one end open, and the first housing body 11 can be a plate-like structure. The first housing body 11 covers the open side of the second housing body 12, so that the first housing body 11 and the second housing body 12 jointly define the assembly space. The first housing body 11 and the second housing body 12 can also be hollow structures with one end open, and the open side of the first housing body 11 covers the open side of the second housing body 12.

[0123] Of course, the box body 10 formed by the first box body 11 and the second box body 12 can be in various shapes, such as a cylinder, a cuboid or a cube, etc. For example, in FIG2 , the box body 10 is in the shape of a cuboid.

[0124] In the battery 100, the battery cell 20 disposed within the housing 10 may be one or more. When multiple battery cells 20 are disposed within the housing 10, the multiple battery cells 20 may be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration refers to a combination of series and parallel configurations within the multiple battery cells 20. The multiple battery cells 20 may be directly connected in series, in parallel, or in a hybrid configuration, and then the entire structure formed by the multiple battery cells 20 is housed within the housing 10. Alternatively, the battery 100 may be constructed by first connecting multiple battery cells 20 in series, in parallel, or in a hybrid configuration to form a battery module, which is then further connected in series, in parallel, or in a hybrid configuration to form a single structure, which is then housed within the housing 10.

[0125] In some embodiments, the battery 100 may further include other structures. For example, the battery 100 may further include a busbar component, which is used to connect the multiple battery cells 20 to achieve electrical connection between the multiple battery cells 20 .

[0126] Each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 20 can be a rectangular parallelepiped, a cylinder, a prism, or other shapes. For example, in FIG3 , the battery cell 20 is a cylindrical structure.

[0127] According to some embodiments of the present application, with reference to FIG3 , and further with reference to FIG4 , FIG5 , FIG6 and FIG7 , FIG4 is an exploded view of the structure of the battery cell 20 provided in some embodiments of the present application, FIG5 is a cross-sectional view of the battery cell 20 provided in some embodiments of the present application, FIG6 is a partial enlarged view of point A of the battery cell 20 shown in FIG5 , and FIG7 is a partial cross-sectional view of the side wall 214 of the shell 21 provided in some embodiments of the present application. The present application provides a battery cell 20, which includes a shell 21, an electrode assembly 22 and an end cover 23. An opening 211 is formed at at least one end of the shell 21 in the first direction X. The electrode assembly 22 is accommodated in the shell 21. The end cover 23 closes the opening 211. The inner surface of the shell 21 includes a first inner circumferential surface 2141a and a blocking surface 2142a arranged and connected along the first direction X. The end of the first inner circumferential surface 2141a away from the blocking surface 2142a encloses an opening 211. The first inner circumferential surface 2141a is welded to the outer circumferential surface 231 of the end cover to form a weld mark 24. Along the first direction X, at least part of the projection of the weld mark 24 is located within the blocking surface 2142a.

[0128] The housing formed by the housing 21 and the end cap 23 can also be used to contain electrolytes, such as electrolytes. The housing formed by the housing 21 and the end cap 23 can have various structural forms, such as a cylinder or a rectangular parallelepiped. Similarly, the housing 21 and the end cap 23 can also be made of various materials, such as aluminum or an aluminum alloy.

[0129] A accommodating cavity 212 is formed inside the shell 21, and an opening 211 is formed at at least one end of the shell 21 in the first direction X. The opening 211 is connected to the accommodating cavity 212, that is, a accommodating cavity 212 with an opening 211 is formed inside the shell 21, and the opening 211 is located at at least one end of the shell 21 in the first direction X. In other words, the shell 21 is a hollow structure with an opening 211 formed at at least one end in the first direction X.

[0130] For example, in Figures 4 and 5, the housing 21 has an opening 211 formed at only one end in the first direction X. The housing 21 may include a bottom wall 213 and a side wall 214. The side wall 214 surrounds the bottom wall 213. Along the first direction X, one end of the side wall 214 is connected to the bottom wall 213, and the other end encloses the opening 211. The side wall 214 and the bottom wall 213 together define a housing cavity 212. The inner surface of the side wall 214 facing the electrode assembly 22 includes a first inner circumferential surface 2141a and a blocking surface 2142a.

[0131] Optionally, the side wall 214 and the bottom wall 213 of the shell 21 can be an integrally formed structure, that is, the side wall 214 and the bottom wall 213 form the shell 21 through an integral molding process, such as stamping or casting. Of course, the side wall 214 and the bottom wall 213 of the shell 21 can also be a separate structure, and the bottom wall 213 and the side wall 214 are connected to each other at one end away from the opening 211 in the first direction X.

[0132] Exemplarily, in FIG. 4 , the side wall 214 and the bottom wall 213 of the housing 21 are integrally formed, that is, the side wall 214 and the bottom wall 213 are an integrated structure.

[0133] When assembling the battery cell 20, the electrode assembly 22 can be placed in the shell 21 first, and the electrolyte can be filled into the shell 21. Then, the end cover 23 is covered on the opening 211 of the shell 21, and the outer peripheral surface 231 of the end cover is welded to the first inner peripheral surface 2141a of the side wall 214 of the shell 21 to complete the assembly of the battery cell 20.

[0134] The shell 21 can be of various shapes, such as a cylinder, a cuboid or a prismatic structure. The shape of the shell 21 can be determined according to the specific shape of the electrode assembly 22. For example, if the electrode assembly 22 is a cylindrical structure, a shell 21 with a cylindrical structure can be selected; if the electrode assembly 22 is a cuboid structure, a shell 21 with a cuboid structure can be selected. Of course, the structure of the end cap 23 can also be various, for example, the end cap 23 is a plate-like structure or a hollow structure with one end open. For example, in Figures 3 and 4, the shell 21 is a cylindrical structure, and the central axis of the shell 21 extends along the first direction X. Correspondingly, the end cap 23 is a circular plate-like structure.

[0135] Of course, it is understandable that the battery cell 20 is not limited to the above structure. For example, the battery cell 20 may include a shell 21 and two end covers 23. A accommodating cavity 212 is formed inside the shell 21. Openings 211 are formed at both ends of the shell 21 in the first direction X. The two openings 211 are connected to the accommodating cavity 212, that is, the shell 21 is a hollow structure with openings 211 formed at both opposite ends in the first direction X. The two end covers 23 are respectively covered at the two openings 211 of the shell 21 and form a sealed connection to form an enclosed space for accommodating the electrode assembly 22 and the electrolyte. That is, the shell 21 only includes side walls 214, so that openings 211 are formed at both opposite ends of the shell 21 in the first direction X, and the two end covers 23 are respectively covered on both sides of the shell 21 in the first direction X to close the corresponding openings 211.

[0136] The end cover 23 closes the opening 211 , that is, the end cover 23 covers the opening 211 of the housing 21 in the first direction X and forms a sealed connection to form a sealed space for accommodating the electrode assembly 22 and the electrolyte.

[0137] Exemplarily, the end cover 23 covers the opening 211 of the housing 21 , and the end cover 23 is welded to the housing 21 .

[0138] In which, the inner surface of the shell 21 includes a first inner circumferential surface 2141a and a blocking surface 2142a arranged and connected along the first direction X, and the end of the first inner circumferential surface 2141a away from the blocking surface 2142a forms an opening 211, that is, the inner surface of the shell 21 facing the electrode assembly 22 at least includes the first inner circumferential surface 2141a and the blocking surface 2142a arranged in sequence along the first direction X and connected to each other, one end of the first inner circumferential surface 2141a in the first direction X is connected to the blocking surface 2142a, and the other end forms the opening 211 of the shell 21, that is, the end of the first inner circumferential surface 2141a away from the blocking surface 2142a in the first direction X is connected to the end surface of the shell 21 forming the opening 211, and the first inner circumferential surface 2141a is an annular structure surrounding the outside of the electrode assembly 22.

[0139] The first inner circumferential surface 2141a is welded to the outer circumferential surface 231 of the end cover to form a weld mark 24, that is, the end cover 23 and the shell 21 are an assembly structure formed by welding the outer circumferential surface 231 of the end cover and the first inner circumferential surface 2141a of the shell 21 to each other, that is, at least a portion of the end cover 23 is inserted into the accommodating cavity 212 of the shell 21 from the opening 211 of the shell 21, and the outer circumferential surface 231 of the end cover and the first inner circumferential surface 2141a of the shell 21 are arranged facing each other and welded to each other.

[0140] Illustratively, the outer circumferential surface 231 of the end cover and the first inner circumferential surface 2141a of the shell 21 are laser welded. Of course, in other embodiments, the outer circumferential surface 231 of the end cover and the first inner circumferential surface 2141a of the shell 21 can also be arc welded, ultrasonically welded, etc.

[0141] Along the first direction X, at least part of the projection of the weld mark 24 is located within the blocking surface 2142a, that is, the blocking surface 2142a can cover at least part of the weld mark 24 in the first direction X. It should be noted that the blocking surface 2142a is connected to the end of the first inner circumferential surface 2141a away from the opening 211. The blocking surface 2142a can be an annular structure extending along the circumference of the first inner circumferential surface 2141a, or it can be an intermittent structure surrounding the circumference of the first inner circumferential surface 2141a, that is, the inner surface of the shell 21 is formed with a plurality of blocking surfaces 2142a arranged at intervals along the circumference of the first inner circumferential surface 2141a.

[0142] In an embodiment of the present application, the projection of the outer peripheral surface 231 of the end cover in the first direction X is located within the blocking surface 2142a, and the projection of the first inner peripheral surface 2141a in the first direction X is arranged around the blocking surface 2142a, so that the projection of the gap between the outer peripheral surface 231 of the end cover and the first inner peripheral surface 2141a in the first direction X is located within the blocking surface 2142a.

[0143] In Figures 6 and 7, the inner surface of the shell 21 facing the accommodating cavity 212 may also include a second inner circumferential surface 2143a, the first inner circumferential surface 2141a, the blocking surface 2142a and the second inner circumferential surface 2143a are arranged in sequence and connected along the first direction X, and the blocking surface 2142a is connected between the first inner circumferential surface 2141a and the second inner circumferential surface 2143a.

[0144] The second inner circumferential surface 2143a is an annular structure surrounding the outer side of the electrode assembly 22 , and the blocking surface 2142a is an annular structure connected between the first inner circumferential surface 2141a and the second inner circumferential surface 2143a and surrounding the outer side of the electrode assembly 22 .

[0145] It should be noted that in the embodiment where the openings 211 are formed at both ends of the housing 21 along the first direction X, the battery cell 20 includes two end covers 23 , and the two end covers 23 respectively close the two openings 211 . The inner surface of the shell 21 facing the accommodating cavity 212 includes two first inner circumferential surfaces 2141a and two blocking surfaces 2142a. Along the first direction X, the two blocking surfaces 2142a are respectively connected to the two ends of the second inner circumferential surface 2143a, and the two first inner circumferential surfaces 2141a are respectively connected to the ends of the two blocking surfaces 2142a away from the second inner circumferential surface 2143a, and the ends of the two first inner circumferential surfaces 2141a away from the blocking surfaces 2142a in the first direction X are both formed with openings 211, so that one first inner circumferential surface 2141a, one blocking surface 2142a, the second inner circumferential surface 2143a, another blocking surface 2142a, and another first inner circumferential surface 2141a are arranged and connected in sequence along the first direction X, and the outer circumferential surfaces 231 of the two end covers can be welded to the two first inner circumferential surfaces 2141a respectively.

[0146] It should be noted that the electrode assembly 22 is the component where electrochemical reactions occur in the battery cell 20. The structure of the electrode assembly 22 can be various. For example, the electrode assembly 22 can be a wound structure formed by winding the positive electrode sheet, the separator and the negative electrode sheet, or it can be a stacked structure formed by stacking the positive electrode sheet, the separator and the negative electrode sheet.

[0147] Illustratively, the separator is an isolation membrane, and a main material of the isolation membrane may be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride.

[0148] Optionally, there may be one or more electrode assemblies 22 housed in the housing cavity 212. For example, in FIG4 , only one electrode assembly 22 is disposed within the battery cell 20. Of course, in other embodiments, there may be two, three, four, five, six, seven, or eight electrode assemblies 22 housed in the housing cavity 212.

[0149] In some embodiments, as shown in Figures 3, 4 and 5, the battery cell 20 may also include an electrode terminal 25, which is insulated and mounted on the bottom wall 213 of the shell 21, and the electrode terminal 25 is electrically connected to the electrode assembly 22 to output or input electrical energy of the battery cell 20.

[0150] It should be noted that the electrode terminal 25 is insulated and mounted on the bottom wall 213 of the housing 21 , that is, no electrical connection is formed between the electrode terminal 25 and the housing 21 .

[0151] As shown in Figures 4 and 5 , the electrode assembly 22 has two tabs 221 with opposite polarities. Specifically, the two tabs 221 serve as the positive and negative tabs of the electrode assembly 22, respectively, for inputting or outputting the positive and negative electrodes of the electrode assembly 22. Along a first direction X, the two tabs 221 are formed at either end of the electrode assembly 22. The tab 221 at one end of the electrode assembly 22 facing the bottom wall 213 in the first direction X is electrically connected to the electrode terminal 25, while the tab 221 at the other end is electrically connected to the end cap 23, thereby enabling the input or output of electrical energy into or out of the battery cell 20. Of course, in other embodiments, the battery cell 20 may also include two electrode terminals 25, each mounted on the bottom wall 213 and the end cap 23, and electrically connected to the two tabs 221 at the two ends of the electrode assembly 22 in the first direction X, thereby enabling the input or output of electrical energy into or out of the battery cell 20. Similarly, in an embodiment where the battery cell 20 includes only one electrode terminal 25, the electrode terminal 25 can also be insulated and installed on the end cover 23, and the pole ear 221 at one end of the electrode assembly 22 facing the end cover 23 in the first direction X is electrically connected to the electrode terminal 25, and the pole ear 221 at the other end is electrically connected to the bottom wall 213 of the shell 21 to realize the input or output of electrical energy of the battery cell 20.

[0152] It should be noted that the tab 221 of the electrode assembly 22 is formed by laminating and connecting the areas of the positive electrode sheets not coated with the positive electrode active material layer, or by laminating and connecting the areas of the negative electrode sheets not coated with the negative electrode active material layer. If the tab 221 is used to output the positive electrode of the electrode assembly 22, the tab 221 is formed by laminating and connecting the areas of the positive electrode sheets not coated with the positive electrode active material layer; if the tab 221 is used to output the negative electrode of the electrode assembly 22, the tab 221 is formed by laminating and connecting the areas of the negative electrode sheets not coated with the negative electrode active material layer.

[0153] Exemplarily, the electrode terminal 25 may be made of a variety of materials. For example, the electrode terminal 25 may be made of copper, iron, aluminum, steel, or aluminum alloy.

[0154] In some embodiments, referring to Figures 4, 5 and 6, the battery cell 20 may further include two current collecting members 26, both of which are arranged in the shell 21, and one of the two current collecting members 26 is used to electrically connect one pole tab 221 and the electrode terminal 25, and the other current collecting member 26 is used to electrically connect the other pole tab 221 and the end cover 23, which helps to reduce the difficulty of assembly between the pole tab 221 and the electrode terminal 25 and between the pole tab 221 and the end cover 23.

[0155] Exemplarily, the material of the current collecting member 26 may be various, for example, the material of the current collecting member 26 may be copper, iron, aluminum, steel or aluminum alloy.

[0156] In some embodiments, the battery cell 20 may further include a pressure relief mechanism disposed on the housing, and configured to release the pressure inside the battery cell 20 when the internal pressure or temperature of the battery cell 20 reaches a predetermined value.

[0157] Optionally, the pressure relief mechanism can be disposed on the end cap 23 of the housing or on the shell 21 of the housing. Similarly, the pressure relief mechanism and the housing can be an integrally formed structure or a separate structure. If the pressure relief mechanism and the housing are separate structures, the pressure relief mechanism can be connected to the housing by welding or other means. Correspondingly, the pressure relief mechanism can be a pressure relief component such as an explosion-proof valve, explosion-proof disk, air valve, pressure relief valve, or safety valve. If the pressure relief mechanism and the housing are an integrally formed structure, the pressure relief mechanism is an area on the housing where a weak structure is formed, such as an area on the housing where a notch is provided.

[0158] In this embodiment, the inner surface of the shell 21 includes a first inner circumferential surface 2141a and a blocking surface 2142a arranged in sequence and connected along the first direction X, and the end of the first inner circumferential surface 2141a away from the blocking surface 2142a encloses the opening 211, and the outer circumferential surface 231 of the end cover and the first inner circumferential surface 2141a of the shell 21 are welded to each other to form a weld mark 24, and at least a portion of the projection of the weld mark 24 in the first direction X is set to be located within the blocking surface 2142a, so that the blocking surface 21 42a is an inclined surface or arc surface connected to the first inner circumferential surface 2141a and inclined or curved from the first inner circumferential surface 2141a toward the electrode assembly 22, so that the end of the shell 21 having the opening 211 has a structure with a larger inner diameter. The battery cell 20 with this structure is convenient for inserting the end cap 23 into the shell 21 through the opening 211, so that the outer circumferential surface 231 of the end cap is welded to the first inner circumferential surface 2141a, and the end cap 23 can be away from the side of the electrode assembly 22. Welding the outer peripheral surface 231 of the end cap and the first inner peripheral surface 2141a of the shell 21 is beneficial to reducing the difficulty of welding, thereby improving the welding quality and welding efficiency, and thus improving the production efficiency of the battery cell 20. On the other hand, it can achieve that the welding gap between the outer peripheral surface 231 of the end cap and the first inner peripheral surface 2141a of the shell 21 is at least partially blocked by the blocking surface 2142a in the first direction X, so that the light beam or heat generated when welding the outer peripheral surface 231 of the end cap and the first inner peripheral surface 2141a of the shell 21 can be blocked by the blocking surface 2142a, thereby alleviating the phenomenon that the light beam or heat generated when welding the outer peripheral surface 231 of the end cap and the first inner peripheral surface 2141a of the shell 21 directly acts on the electrode assembly 22, thereby reducing the phenomenon of burning the electrode assembly 22 contained in the shell 21 when the end cap 23 and the shell 21 are welded to each other, and further effectively reducing the phenomenon of damaging the electrode assembly 22 during the assembly process of the battery cell 20, thereby improving the production quality of the battery cell 20.

[0159] According to some embodiments of the present application, as shown in Figures 5, 6, and 7, the blocking surface 2142a is an annular structure extending along the circumference of the first inner circumferential surface 2141a. In other words, the blocking surface 2142a is a structure surrounding the outside of the electrode assembly 22.

[0160] In this embodiment, by setting the blocking surface 2142a as an annular structure extending along the circumference of the first inner circumferential surface 2141a, the blocking surface 2142a can block the welding gap between the outer circumferential surface 231 of the end cover and the first inner circumferential surface 2141a of the shell 21 along the first direction X over the entire circumference of the first inner circumferential surface 2141a, thereby improving the blocking effect of the blocking surface 2142a on the light beam or heat generated by the welding when the outer circumferential surface 231 of the end cover and the first inner circumferential surface 2141a of the shell 21 are welded together, thereby further reducing the phenomenon of burning the electrode assembly 22 when the end cover 23 and the shell 21 are welded to each other, thereby further improving the production quality of the battery cell 20.

[0161] According to some embodiments of the present application, as shown in FIG. 7 , along the first direction X, the size of the first inner circumferential surface 2141 a is D1 , satisfying 0.2 mm ≤ D1 ≤ 3.2 mm.

[0162] The dimension D1 of the first inner circumferential surface 2141 a is the distance in the first direction X between one end of the first inner circumferential surface 2141 a connected to the blocking surface 2142 a and one end of the first inner circumferential surface 2141 a forming the opening 211 .

[0163] Exemplarily, the dimension D1 of the first inner circumferential surface 2141a may be 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.8 mm, 1 mm, 1.1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, 2.2 mm, 2.5 mm, 2.8 mm, 3 mm or 3.2 mm, etc.

[0164] In this embodiment, the dimension of the first inner circumferential surface 2141a in the first direction X is 0.2 mm to 3.2 mm. On the one hand, by setting the dimension of the first inner circumferential surface 2141a in the first direction X to be greater than or equal to 0.2 mm, the area of ​​the region where the shell 21 and the end cover 23 are welded to each other is increased, which is beneficial to improving the welding firmness between the shell 21 and the end cover 23, thereby improving the assembly quality of the battery cell 20 and reducing the difficulty of welding between the outer circumferential surface 231 of the end cover and the first inner circumferential surface 2141a of the shell 21. On the other hand, by setting the dimension of the first inner circumferential surface 2141a in the first direction X to be less than or equal to 3.2 mm, the phenomenon of excessive space occupied by the first inner circumferential surface 2141a and resulting in waste of the internal space of the shell 21 is alleviated, which is beneficial to improving the internal space utilization rate of the battery cell 20.

[0165] According to some embodiments of the present application, as shown in Figures 5, 6, and 7, the inner surface of the housing 21 may further include a second inner circumferential surface 2143a. The first inner circumferential surface 2141a, the blocking surface 2142a, and the second inner circumferential surface 2143a are arranged along the first direction X, and the blocking surface 2142a connects the first inner circumferential surface 2141a and the second inner circumferential surface 2143a. The projection of the second inner circumferential surface 2143a in the first direction X is located on the inner side of the first inner circumferential surface 2141a.

[0166] Among them, the first inner circumferential surface 2141a, the blocking surface 2142a and the second inner circumferential surface 2143a are arranged along the first direction X, and the blocking surface 2142a connects the first inner circumferential surface 2141a and the second inner circumferential surface 2143a. That is, the first inner circumferential surface 2141a, the blocking surface 2142a and the second inner circumferential surface 2143a are structures arranged in sequence and connected along the first direction X, so that the blocking surface 2142a and the second inner circumferential surface 2143a are both annular structures extending along the circumference of the first inner circumferential surface 2141a and surrounding the outside of the electrode assembly 22.

[0167] The projection of the second inner circumferential surface 2143a in the first direction X is located on the inner side of the first inner circumferential surface 2141a, that is, in a plane perpendicular to the first direction X, the positive projection of the first inner circumferential surface 2141a surrounds the outer side of the positive projection of the second inner circumferential surface 2143a, so that the first inner circumferential surface 2141a is farther away from the electrode assembly 22 than the second inner circumferential surface 2143a in the radial direction Y of the first inner circumferential surface.

[0168] It should be noted that, in an embodiment where the projection of the second inner circumferential surface 2143a in the first direction X is located on the inner side of the first inner circumferential surface 2141a, the blocking surface 2142a can be an inclined surface connected between the first inner circumferential surface 2141a and the second inner circumferential surface 2143a, or it can be an arcuate surface connected between the first inner circumferential surface 2141a and the second inner circumferential surface 2143a. For example, in Figure 7, the blocking surface 2142a is an arcuate surface connected between the first inner circumferential surface 2141a and the second inner circumferential surface 2143a.

[0169] Of course, in other embodiments, the first inner circumferential surface 2141a and the second inner circumferential surface 2143a may also be coplanar structures, that is, the first inner circumferential surface 2141a and the second inner circumferential surface 2143a are flush, so that the projection of the first inner circumferential surface 2141a in the first direction X and the projection of the second inner circumferential surface 2143a in the first direction X coincide with each other, so that the blocking surface 2142a is a convex surface protruding toward one side of the electrode assembly 22 and connected between the first inner circumferential surface 2141a and the second inner circumferential surface 2143a. It should be noted that the first inner circumferential surface 2141a and the second inner circumferential surface 2143a can be a completely coplanar structure, that is, the first inner circumferential surface 2141a and the second inner circumferential surface 2143a are parallel to each other and completely aligned. Of course, the first inner circumferential surface 2141a and the second inner circumferential surface 2143a can be coplanar and have an approximately coplanar structure. There is a small error between the first inner circumferential surface 2141a and the second inner circumferential surface 2143a, that is, the first inner circumferential surface 2141a and the second inner circumferential surface 2143a can be coplanar with a small angle or distance.

[0170] In this embodiment, the inner surface of the shell 21 also includes a second inner circumferential surface 2143a, and the blocking surface 2142a is connected between the first inner circumferential surface 2141a and the second inner circumferential surface 2143a, and the projection of the second inner circumferential surface 2143a in the first direction X is located on the inner side of the first inner circumferential surface 2141a, so that the inner diameter of the second inner circumferential surface 2143a is smaller than the inner diameter of the first inner circumferential surface 2141a, so as to form a blocking surface 2142a that is inclined or curved in the direction close to the electrode assembly 22 between the first inner circumferential surface 2141a and the second inner circumferential surface 2143a, thereby reducing the difficulty of forming the blocking surface 2142a on the inner surface of the shell 21, which is beneficial to reducing the manufacturing difficulty of the battery cell 20 and improving the production efficiency of the battery cell 20.

[0171] 7 , the first inner circumferential surface 2141a is parallel to the second inner circumferential surface 2143a. In other words, any position of the first inner circumferential surface 2141a and the second inner circumferential surface 2143a are equidistant from each other in the radial direction Y of the first inner circumferential surface.

[0172] For example, in an embodiment where the housing 21 is cylindrical, correspondingly, in a plane perpendicular to the first direction X, the orthographic projection of the first inner circumferential surface 2141a and the orthographic projection of the second inner circumferential surface 2143a are both the center of the circle, and the two are concentric circles.

[0173] In this embodiment, by arranging the first inner circumferential surface 2141a and the second inner circumferential surface 2143a in parallel with each other, such that the first inner circumferential surface 2141a surrounds the outside of the second inner circumferential surface 2143a, and the distance between the first inner circumferential surface 2141a and the second inner circumferential surface 2143a is equal at any position along the radial direction Y of the first inner circumferential surface, the regularity of the shape of the housing 21 is improved, and the assembly of the electrode assembly 22 into the housing 21 is facilitated, thereby reducing the difficulty of assembling the battery cell 20. According to some embodiments of the present application, as shown in FIG7 , along the radial direction Y of the first inner circumferential surface, the minimum distance between the first inner circumferential surface 2141a and the second inner circumferential surface 2143a is D2, which satisfies the condition 0.1 mm ≤ D2 ≤ 1.2 mm. That is, in a plane perpendicular to the first direction X, the orthographic projection of the first inner circumferential surface 2141a surrounds the outside of the orthographic projection of the second inner circumferential surface 2143a, and the distance between the orthographic projection of the first inner circumferential surface 2141a and the orthographic projection of the second inner circumferential surface 2143a is D2.

[0174] Exemplarily, the minimum distance D2 between the first inner circumferential surface 2141a and the second inner circumferential surface 2143a can be 0.1mm, 0.11mm, 0.12mm, 0.15mm, 0.18mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.15mm or 1.2mm.

[0175] In this embodiment, the spacing between the first inner circumferential surface 2141a and the second inner circumferential surface 2143a in the radial direction Y of the first inner circumferential surface is 0.1 mm to 1.2 mm. On the one hand, the spacing between the first inner circumferential surface 2141a and the second inner circumferential surface 2143a in the radial direction Y of the first inner circumferential surface is set to be greater than or equal to 0.1 mm to alleviate the phenomenon that the area of ​​the blocking surface 2142a formed between the first inner circumferential surface 2141a and the second inner circumferential surface 2143a is too small, thereby improving the welding connection between the blocking surface 2142a and the outer circumferential surface 231 of the end cover and the first inner circumferential surface 2141a of the shell 21. The first inner circumference 2141a and the second inner circumference 2143a are connected to each other to form a blocking surface 2142a between the first inner circumference 2141a and the second inner circumference 2143a. On the other hand, the spacing between the first inner circumference 2141a and the second inner circumference 2143a in the radial direction Y of the first inner circumference is set to be less than or equal to 1.2 mm to alleviate the phenomenon of excessive thinning or outward expansion of the area where the first inner circumference 2141a of the shell 21 is formed, thereby reducing the processing difficulty of the shell 21, making it easier to form and manufacture, and reducing the phenomenon of excessive waste of internal space of the shell 21.

[0176] According to some embodiments of the present application, as shown in Figures 4, 5, 6, and 7, the housing 21 may include a sidewall 214 that surrounds the outer side of the electrode assembly 22. The sidewall 214 has an opening 211 formed at at least one end thereof in the first direction X. The sidewall 214 includes a first sidewall 2141, a connecting wall 2142, and a second sidewall 2143 that are sequentially arranged and connected along the first direction X. The inner surface of the first sidewall 2141 is a first inner circumferential surface 2141a, the inner surface of the connecting wall 2142 is a blocking surface 2142a, and the inner surface of the second sidewall 2143 is a second inner circumferential surface 2143a. Along the first direction X, the projection of the outer circumferential surface 2143b of the second sidewall is located inward of the outer circumferential surface 2141b of the first sidewall.

[0177] Among them, the side wall 214 surrounds the outside of the electrode assembly 22, and an opening 211 is formed at at least one end of the side wall 214 in the first direction X. That is, the side wall 214 of the shell 21 is a hollow structure with an opening 211 formed at at least one end in the first direction X, and the central axis of the side wall 214 extends along the first direction X, that is, the side wall 214 is a structure that surrounds the outside of the electrode assembly 22 around the axis extending along the first direction X.

[0178] The side wall 214 includes a first side wall 2141, a connecting wall 2142 and a second side wall 2143 arranged in sequence and connected along the first direction X, that is, the connecting wall 2142 is a structure connected between the first side wall 2141 and the second side wall 2143 in the first direction X, so that the first side wall 2141, the connecting wall 2142 and the second side wall 2143 are all annular structures surrounding the outside of the electrode assembly 22.

[0179] The inner surface of the first side wall 2141 is the first inner circumferential surface 2141a, that is, the surface of the first side wall 2141 facing the electrode assembly 22 is the first inner circumferential surface 2141a of the shell 21. Similarly, the inner surface of the connecting wall 2142 is the blocking surface 2142a, that is, the surface of the connecting wall 2142 facing the electrode assembly 22 is the blocking surface 2142a of the shell 21, and the inner surface of the second side wall 2143 is the second inner circumferential surface 2143a, that is, the surface of the second side wall 2143 facing the electrode assembly 22 is the second inner circumferential surface 2143a of the shell 21.

[0180] Along the first direction X, the projection of the outer peripheral surface 2143b of the second side wall is located on the inner side of the outer peripheral surface 2141b of the first side wall, that is, in a plane perpendicular to the first direction X, the orthographic projection of the outer peripheral surface 2141b of the first side wall surrounds the outer side of the orthographic projection of the outer peripheral surface 2143b of the second side wall.

[0181] In Figures 4 and 5, the housing 21 may further include a bottom wall 213, which is connected to one end of the side wall 214 in the first direction X away from the opening 211. The bottom wall 213 and the end caps 23 are arranged opposite each other along the first direction X, so that the housing 21 has an opening 211 formed at only one end in the first direction X. The bottom wall 213 and the side wall 214 jointly define a receiving cavity 212 for accommodating the electrode assembly 22. Of course, in other embodiments, the housing 21 may not be provided with the bottom wall 213, that is, the housing 21 only includes the side wall 214, so that the housing 21 has an opening 211 formed at both ends in the first direction X. Correspondingly, the battery cell 20 includes two end caps 23, which are respectively connected to the two ends of the housing 21 in the first direction X and respectively close the two openings 211, so that the two end caps 23 are arranged opposite each other along the first direction X.

[0182] It should be noted that, in an embodiment in which openings 211 are formed at both ends of the shell 21 in the first direction X, the side wall 214 includes two first side walls 2141, two connecting walls 2142 and one second side wall 2143. A first side wall 2141, a connecting wall 2142, a second side wall 2143, another connecting wall 2142 and another first side wall 2141 are arranged and connected in sequence, that is, the second side wall 2143 is connected to the connecting wall 2142 at both ends in the first direction X, and the two connecting walls 2142 are connected to the first side wall 2141 at one end away from the second side wall 2143, so that the shell 21 includes two first inner circumferential surfaces 2141a, two blocking surfaces 2142a and one second inner circumferential surface 2143a.

[0183] In this embodiment, the first inner circumferential surface 2141a, the blocking surface 2142a and the second inner circumferential surface 2143a of the shell 21 are respectively the inner surfaces of the first side wall 2141, the connecting wall 2142 and the second side wall 2143 of the side wall 214 facing the electrode assembly 22. By setting the projection of the outer circumferential surface 2143b of the second side wall in the first direction X to be located on the inner side of the outer circumferential surface 2141b of the first side wall, the first side wall 2141 of the shell 21 is a structure that extends outward in the radial direction Y of the first inner circumferential surface compared to the second side wall 2143, and the connecting wall 2142 is a curved or inclined structure connected between the first side wall 2141 and the second side wall 2143, so as to realize the formation of the first inner circumferential surface 2141a, the blocking surface 2142a and the second inner circumferential surface 2143a on the inner surface of the side wall 214. The structure is simple and easy to implement, which is conducive to reducing the processing difficulty of the shell 21 of the battery cell 20.

[0184] According to some embodiments of the present application, as shown in FIG. 7 , the wall thickness of the first sidewall 2141 is smaller than the wall thickness of the second sidewall 2143 .

[0185] In this embodiment, by setting the wall thickness of the first side wall 2141 to be smaller than the wall thickness of the second side wall 2143, the distance between the first inner circumferential surface 2141a and the second inner circumferential surface 2143a in the radial direction Y of the first inner circumferential surface is kept constant, and the outward expansion dimension of the first side wall 2141 in the radial direction Y of the first inner circumferential surface can be effectively reduced compared with the second side wall 2143, thereby facilitating the reduction of the size difference on the outer circumferential surface of the shell 21, and reducing the interference between the battery cells 20 and the space occupied by the battery cells 20 during the subsequent assembly of the battery cells 20 into groups.

[0186] In some embodiments, referring to FIG. 7 , the thickness of the first sidewall 2141 is D3 , and the thickness of the second sidewall 2143 is D4 , satisfying 1>D3 / D4≥0.55.

[0187] Exemplarily, the wall thickness D3 of the first side wall 2141 may be 0.55 times, 0.56 times, 0.58 times, 0.6 times, 0.62 times, 0.65 times, 0.68 times, 0.7 times, 0.75 times, 0.8 times, 0.85 times, 0.9 times, 0.95 times or 0.99 times the wall thickness D4 of the second side wall 2143.

[0188] In this embodiment, the wall thickness of the first side wall 2141 is set to be greater than or equal to 0.55 times the wall thickness of the second side wall 2143 to alleviate the phenomenon of transitional thinning of the first side wall 2141, thereby reducing the outward expansion size of the first side wall 2141 compared to the second side wall 2143 and improving the structural strength of the first side wall 2141, thereby reducing the deformation or damage of the first side wall 2141 during use, and improving the welding quality between the first inner circumference 2141a of the first side wall 2141 and the outer circumference 231 of the end cover.

[0189] Of course, the structure of the battery cell 20 is not limited to this. In some embodiments, the battery cell 20 may also have other structures. For example, the shell 21 may include a side wall 214, which surrounds the outside of the electrode assembly 22. The side wall 214 is formed with an opening 211 at at least one end in the first direction X. The side wall 214 includes a first side wall 2141, a connecting wall 2142, and a second side wall 2143 arranged and connected in sequence along the first direction X. The inner surface of the first side wall 2141 is a first inner circumferential surface 2141a, the inner surface of the connecting wall 2142 is a blocking surface 2142a, the inner surface of the second side wall 2143 is a second inner circumferential surface 2143a, and the outer circumferential surface 2143b of the second side wall is coplanar with the outer circumferential surface 2141b of the first side wall. That is to say, the outer peripheral surface 2143b of the second side wall is flush with the outer peripheral surface 2141b of the first side wall, that is, the entire outer peripheral surface of the side wall 214 is a flat structure, so that the wall thickness of the first side wall 2141 is a structure that is thinner than the wall thickness of the second side wall 2143, and the wall thickness of the connecting wall 2142 is a structure that gradually decreases from one end connected to the second side wall 2143 to the end connected to the first side wall 2141, so as to form a first inner peripheral surface 2141a on the inner surface of the first side wall 2141, a second inner peripheral surface 2143a on the inner surface of the second side, and a blocking surface 2142a on the inner peripheral surface of the connecting wall 2142. It should be noted that the outer peripheral surface 2143b of the second side wall and the outer peripheral surface 2141b of the first side wall can be completely coplanar structures, that is, the outer peripheral surface 2143b of the second side wall and the outer peripheral surface 2141b of the first side wall are parallel to each other and completely aligned. Of course, the outer peripheral surface 2143b of the second side wall and the outer peripheral surface 2141b of the first side wall can be approximately coplanar structures, and there is a small error between the outer peripheral surface 2143b of the second side wall and the outer peripheral surface 2141b of the first side wall, that is, the outer peripheral surface 2143b of the second side wall and the outer peripheral surface 2141b of the first side wall can be coplanar with a small angle or distance.

[0190] In this embodiment, the first inner circumferential surface 2141a, the blocking surface 2142a and the second inner circumferential surface 2143a of the shell 21 are respectively the inner surfaces of the first side wall 2141, the connecting wall 2142 and the second side wall 2143 facing the electrode assembly 22, and the outer circumferential surface 2143b of the second side wall is set to a coplanar structure with the outer circumferential surface 2141b of the first side wall, that is, the outer circumferential surface 2143b of the second side wall is flush with the outer circumferential surface 2141b of the first side wall, so that the first side wall 2141 is relatively larger than the second side wall. The wall 2143 is thinned to form a blocking surface 2142a between the first inner circumferential surface 2141a and the second inner circumferential surface 2143a. The battery cell 20 adopting this structure can form the blocking surface 2142a on the inner surface of the side wall 214 while improving the consistency of the outer circumferential surface of the shell 21, thereby reducing the size difference of the outer circumferential surface of the shell 21, and reducing the interference between the battery cells 20 and the space occupied by the battery cells 20 during the subsequent assembly of the battery cells 20.

[0191] According to some embodiments of the present application, as shown in FIG6 , the end cap 23 abuts against the blocking surface 2142 a along the first direction X. That is, a portion of the end cap 23 contacts the blocking surface 2142 a in the first direction X, such that a portion of the projection of the end cap 23 in the first direction X is located within the blocking surface 2142 a.

[0192] In this embodiment, by setting the end cover 23 to abut against the blocking surface 2142a along the first direction X, the blocking surface 2142a can also be used for the end cover 23 to abut in the first direction X. The battery cell 20 with this structure can also play a certain positioning and limiting role on the end cover 23 through the blocking surface 2142a, so as to alleviate the phenomenon that the end cover 23 is inserted too much in the accommodating cavity 212, thereby facilitating the improvement of the assembly accuracy and assembly quality between the end cover 23 and the shell 21, thereby improving the production quality of the battery cell 20, and on the other hand, it can achieve the blocking effect. The surface 2142a is in contact with at least a portion of the end cover 23 to further enhance the effect of the blocking surface 2142a in shielding the welding gap between the outer peripheral surface 231 of the end cover and the first inner peripheral surface 2141a of the shell 21, thereby further enhancing the blocking effect of the blocking surface 2142a on the light beam or heat generated by the welding when the outer peripheral surface 231 of the end cover is welded to the first inner peripheral surface 2141a of the shell 21, thereby further reducing the phenomenon of burning the electrode assembly 22 when the end cover 23 and the shell 21 are welded to each other, and thus being beneficial to improving the production quality of the battery cell 20.

[0193] According to some embodiments of the present application, please continue to refer to Figure 6, the end cover 23 has a first surface 232 facing the electrode assembly 22 in the first direction X, the first surface 232 is connected to the outer peripheral surface 231 of the end cover through a transition surface 233, and the transition surface 233 abuts against the blocking surface 2142a.

[0194] Among them, the first surface 232 is connected to the outer peripheral surface 231 of the end cover through a transition surface 233, and the transition surface 233 abuts against the blocking surface 2142a. That is, the first surface 232 of the end cover 23 and the outer peripheral surface 231 of the end cover are structures connected to each other through the transition surface 233, so that a transition surface 233 is formed at the corner of the end cover 23, and the transition surface 233 is in contact with the blocking surface 2142a.

[0195] For example, in FIG6 , the transition surface 233 is a rounded surface formed between the first surface 232 of the end cover 23 and the outer peripheral surface 231 of the end cover. Of course, in other embodiments, the transition surface 233 may also be a chamfered surface formed between the first surface 232 of the end cover 23 and the outer peripheral surface 231 of the end cover.

[0196] In this embodiment, a transition surface 233 is formed between the first surface 232 of the end cover 23 and the outer peripheral surface 231 of the end cover, and the end cover 23 is a structure in which the transition surface 233 and the blocking surface 2142a abut against each other. Therefore, on the one hand, the fitting effect between the end cover 23 and the blocking surface 2142a can be improved, so as to further improve the effect of the blocking surface 2142a in covering the welding gap between the outer peripheral surface 231 of the end cover and the first inner peripheral surface 2141a of the shell 21, and the positioning and limiting effect of the blocking surface 2142a on the end cover 23 can be improved. On the other hand, the transition surface 233 can also play a certain guiding role when the end cover 23 is assembled in the shell 21, so that at least a part of the end cover 23 can be inserted into the shell 21 from the opening 211 of the shell 21, which is conducive to reducing the difficulty of assembly between the end cover 23 and the shell 21.

[0197] In some embodiments, referring to FIG. 6 and FIG. 7 , the transition surface 233 includes a first rounded surface, and the blocking surface 2142 a includes a second rounded surface, and the second rounded surface and the first rounded surface fit together and adhere to each other.

[0198] The transition surface 233 includes a first rounded surface, that is, at least a portion of the transition surface 233 is a rounded surface structure. For example, in FIG6 , the entire transition surface 233 is a rounded surface structure, that is, the transition surface 233 is a first rounded surface.

[0199] Similarly, the blocking surface 2142a includes a second rounded surface, that is, at least a portion of the blocking surface 2142a is a rounded surface structure. For example, in Figure 7, the blocking surface 2142a is composed of two rounded surface structures connected to each other, that is, the blocking surface 2142a includes a second rounded surface and a third rounded surface connected to each other, the second rounded surface is connected to the first inner circumferential surface 2141a, and the third rounded surface is connected to the second inner circumferential surface 2143a, and the second rounded surface of the blocking surface 2142a fits with the first rounded surface of the transition surface 233 and fits with each other.

[0200] The second rounded surface matches the first rounded surface and fits with each other, that is, at least a portion of the transition surface 233 and at least a portion of the blocking surface 2142a have the same shape and fit with each other.

[0201] In this embodiment, the transition surface 233 is formed with a first rounded corner, and the blocking surface 2142a is formed with a second rounded corner surface, and the second rounded corner surface fits with the first rounded corner surface and fits with each other, so that at least a portion of the transition surface 233 fits with at least a portion of the blocking surface 2142a and fits with each other, thereby further improving the fitting effect between the end cover 23 and the blocking surface 2142a, and further improving the effect of the blocking surface 2142a in covering the welding gap between the outer peripheral surface 231 of the end cover and the first inner peripheral surface 2141a of the shell 21, and further improving the positioning and limiting effect of the blocking surface 2142a on the end cover 23.

[0202] According to some embodiments of the present application, referring to Figures 5, 6 and 7, the shell 21 has a first end face 215 at one end where an opening 211 is formed in the first direction X, and the first end face 215 is connected to the first inner circumferential surface 2141a, and the end cover 23 has a second surface 234 facing away from the electrode assembly 22 in the first direction X, the second surface 234 is connected to the outer circumferential surface 231 of the end cover, and the second surface 234 is coplanar with the first end face 215.

[0203] In the embodiment where the housing 21 includes a bottom wall 213 and a side wall 214, the first end surface 215 is the end surface of the side wall 214 away from the bottom wall 213 in the first direction X, and the opening 211 is formed on the first end surface 215. In the embodiment where the side wall 214 includes a first side wall 2141, a connecting wall 2142, and a second side wall 2143 arranged in sequence and connected along the first direction X, the first end surface 215 is the end surface of the first side wall 2141 away from the connecting wall 2142.

[0204] Illustratively, the first end surface 215 of the shell 21 and the first inner circumferential surface 2141a of the shell 21 are perpendicular to and connected to each other. Similarly, the outer circumferential surface 231 of the end cover and the second surface 234 of the end cover 23 are perpendicular to and connected to each other.

[0205] The second surface 234 is coplanar with the first end surface 215 , that is, the second surface 234 of the end cover 23 and the first end surface 215 of the housing 21 are flush with each other. Exemplarily, the second surface 234 of the end cover 23 and the first end surface 215 of the housing 21 are flush with each other and are both perpendicular to the first direction X. It should be noted that the coplanarity of the second surface 234 and the first end surface 215 can be a completely coplanar structure, that is, the second surface 234 and the first end surface 215 are parallel to each other and completely aligned. Of course, the coplanarity of the second surface 234 and the first end surface 215 can also be an approximately coplanar structure, with a small error between the second surface 234 and the first end surface 215, that is, the coplanarity of the second surface 234 and the first end surface 215 can be at a small angle or distance.

[0206] In this embodiment, the first end face 215 connected to the first inner circumferential surface 2141a of the shell 21 and the second surface 234 of the end cover 23 facing away from the electrode assembly 22 and connected to the outer circumferential surface 231 of the end cover are set to a coplanar structure, so that the first end face 215 of the shell 21 and the second surface 234 of the end cover 23 are flush structures, which helps to reduce the difficulty of welding between the first inner circumferential surface 2141a of the shell 21 and the outer circumferential surface 231 of the end cover, and helps to improve the welding quality between the first inner circumferential surface 2141a of the shell 21 and the outer circumferential surface 231 of the end cover.

[0207] According to some embodiments of the present application, as shown in FIG. 6 , along the first direction X, the end cap 23 has a third surface 235 farthest from the electrode assembly 22 , and the third surface 235 is farther from the electrode assembly 22 than the second surface 234 .

[0208] The end cap 23 has a third surface 235 farthest from the electrode assembly 22 . That is, the third surface 235 is a surface of the end cap 23 that is away from the electrode assembly 22 in the first direction X and farthest from the electrode assembly 22 .

[0209] The third surface 235 is farther away from the electrode assembly 22 than the second surface 234 . That is, in the first direction X, the second surface 234 is located between the third surface 235 and the electrode assembly 22 .

[0210] In this embodiment, a third surface 235 is further formed on the side of the end cover 23 facing away from the electrode assembly 22 in the first direction X, and the third surface 235 is farther away from the electrode assembly 22 than the second surface 234. Therefore, on the one hand, the support and blocking of the third surface 235 can play a certain protective role on the weld mark 24 between the first inner circumferential surface 2141a of the shell 21 and the outer circumferential surface 231 of the end cover, thereby alleviating the wear of the weld mark 24, thereby improving the connection reliability between the end cover 23 and the shell 21, and helping to reduce the risk of connection failure between the end cover 23 and the shell 21. On the other hand, it can reduce the impact of the weld mark 24 protruding from the second surface 234 of the end cover 23 on the height dimension of the battery cell 20 in the first direction X, which is conducive to reducing the difficulty of subsequent assembly of the battery cell 20 and reducing the interference effect of the weld mark 24 during the subsequent assembly of the battery cell 20.

[0211] In some embodiments, referring to FIG. 6 , the end cap 23 is formed with a protrusion 236 that protrudes from the second surface 234 along the first direction X, and the protrusion 236 forms a third surface 235 on a side facing away from the electrode assembly 22 in the first direction X. In other words, the protrusion 236 is formed on a side of the end cap 23 facing away from the electrode assembly 22 in the first direction X, and the protrusion 236 protrudes from the second surface 234, so that the protrusion 236 forms the third surface 235 on a side facing away from the electrode assembly 22 in the first direction X.

[0212] In this embodiment, a protrusion 236 is formed on the side of the end cover 23 away from the electrode assembly 22 along the first direction X, the protrusion 236 protrudes from the second surface 234, and a third surface 235 is formed on the side of the protrusion 236 away from the electrode assembly 22 in the first direction X, so as to form a third surface 235 on the end cover 23 that is farther away from the electrode assembly 22 than the second surface 234. The structure is simple and easy to implement.

[0213] According to some embodiments of the present application, as shown in FIG. 6 , along the first direction X, the distance between the third surface 235 and the second surface 234 is D5 , satisfying 0.1 mm ≤ D5 ≤ 0.6 mm.

[0214] The distance D5 between the third surface 235 and the second surface 234 is the distance that the third surface 235 is farther from the electrode assembly 22 than the second surface 234 in the first direction X, and is also the height dimension of the protrusion 236 protruding from the second surface 234 in the first direction X.

[0215] Exemplarily, along the first direction X, the distance D5 between the third surface 235 and the second surface 234 can be 0.1mm, 0.11mm, 0.12mm, 0.15mm, 0.18mm, 0.2mm, 0.22mm, 0.25mm, 0.28mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm or 0.6mm, etc.

[0216] In this embodiment, the distance between the third surface 235 and the second surface 234 of the end cap 23 is 0.1 mm to 0.6 mm. Setting the distance between the third surface 235 and the second surface 234 to be greater than or equal to 0.1 mm increases the distance between the third surface 235 and the second surface 234, thereby improving the protective effect of the third surface 235 on the weld mark 24 and alleviating wear of the weld mark 24. Furthermore, the impact of the weld mark 24 on the height dimension of the battery cell 20 in the first direction X can be further reduced, thereby reducing the difficulty of subsequent assembly of the battery cells 20 and the risk of interference caused by the weld mark 24 during the subsequent assembly of the battery cells 20. Furthermore, setting the distance between the third surface 235 and the second surface 234 to be less than or equal to 0.6 mm alleviates the phenomenon of the third surface 235 being too far away from the electrode assembly 22 compared to the second surface 234. This reduces the difficulty of forming the third surface 235 on the end cap 23 and saves space occupied by the battery cells 20 in the first direction X, thereby improving the space utilization of the battery cells 20.

[0217] 6 , the end cap 23 has a first surface 232 facing the electrode assembly 22 in the first direction X. Along the first direction X, a first groove 237 is formed on the first surface 232 at a position corresponding to the protrusion 236 .

[0218] Illustratively, the protrusion 236 disposed on the side of the end cap 23 facing away from the electrode assembly 22 is formed by a stamping process, so as to form the protrusion 236 on the side of the end cap 23 facing away from the electrode assembly 22, and form a first groove 237 on the side of the end cap 23 facing the electrode assembly 22 and corresponding to the position of the protrusion 236. Of course, the processing method of the protrusion 236 disposed on the side of the end cap 23 facing away from the electrode assembly 22 is not limited to this. In other embodiments, the protrusion 236 disposed on the side of the end cap 23 facing away from the electrode assembly 22 can also be formed by a processing process such as casting or milling.

[0219] In this embodiment, a first groove 237 is formed on the first surface 232 of the end cover 23 facing the electrode assembly 22 and in an area corresponding to the protrusion 236, so that the protrusion 236 of the end cover 23 is a structure that can be formed by stamping, so that the protrusion 236 and the first groove 237 are respectively formed on both sides of the end cover 23 along the first direction X, which is beneficial to reduce the manufacturing difficulty of the end cover 23 and improve the production efficiency of the end cover 23.

[0220] According to some embodiments of the present application, referring to Figures 8 and 9, Figure 8 is a cross-sectional view of a battery cell 20 provided in still further embodiments of the present application, and Figure 9 is a partially enlarged view of a portion B of the battery cell 20 shown in Figure 8. The second surface 234 is provided with a second groove 238, which is an annular groove extending along the circumference of the first inner circumferential surface 2141a.

[0221] In the embodiment where the end cover 23 is formed with a protrusion 236 , the second groove 238 is disposed around the outer side of the protrusion 236 , and the second surface 234 and the third surface 235 are connected to each other through the groove wall of the second groove 238 .

[0222] It should be noted that, in an embodiment in which the battery cell 20 is provided with a current collecting component 26 and the current collecting component 26 is interconnected with the end cover 23, the current collecting component 26 is welded to the area of ​​the end cover 23 where the second groove 238 is provided, that is, the current collecting component 26 is welded to the groove bottom wall 213 of the second groove 238, so that the thickness of the area in which the end cover 23 and the current collecting component 26 are welded to each other can be reduced through the second groove 238, so as to reduce the welding power required for welding the current collecting component 26 and the end cover 23, and can reduce the welding difficulty.

[0223] In this embodiment, a second groove 238 is provided on the second surface 234, and the second groove 238 is an annular structure extending circumferentially along the first inner circumferential surface 2141a, so that the first inner circumferential surface 2141a of the shell 21 and the outer circumferential surface 231 of the end cover are structures surrounding the outside of the second groove 238. The battery cell 20 adopting this structure can absorb the stress generated by the welding connection between the first inner circumferential surface 2141a of the shell 21 and the outer circumferential surface 231 of the end cover through the second groove 238, so as to reduce the deformation or damage of the end cover 23 due to the welding stress, and can reduce the influence of the welding stress on other components on the end cover 23, thereby facilitating the improvement of the assembly quality of the battery cell 20.

[0224] According to some embodiments of the present application, referring to FIG. 3 , FIG. 4 and FIG. 5 , the housing 21 is cylindrical, and the central axis of the housing 21 extends along the first direction X.

[0225] The housing 21 is cylindrical, and correspondingly, the end cover 23 of the battery cell 20 is a circular plate-shaped structure.

[0226] The central axis of the housing 21 extends along the first direction X, that is, the housing 21 is a cylindrical structure with a central axis extending along the first direction X.

[0227] It should be noted that, in other embodiments, the shape of the housing 21 may also be cylindrical, rectangular, cube-shaped, or prism-shaped.

[0228] In this embodiment, the housing 21 of the battery cell 20 is cylindrical, so as to facilitate processing to form a cylindrical battery cell 20 , so that the battery cell 20 has the advantages of high capacity, long cycle life, and wide operating temperature range.

[0229] In some embodiments, the first inner circumferential surface 2141a is laser welded to the outer circumferential surface 231 of the end cover. In other words, the end cover 23 and the housing 21 are assembled with each other by laser welding.

[0230] Exemplarily, when laser welding the first inner circumferential surface 2141a and the outer circumferential surface 231 of the end cover, the welding equipment emits laser from the side of the end cover 23 where the second surface 234 is formed and welds the first inner circumferential surface 2141a and the outer circumferential surface 231 of the end cover.

[0231] In this embodiment, laser welding is used to connect the first inner circumferential surface 2141a of the shell 21 and the outer circumferential surface 231 of the end cover. On the one hand, it can effectively improve the welding efficiency between the first inner circumferential surface 2141a of the shell 21 and the outer circumferential surface 231 of the end cover, so as to improve the assembly efficiency of the battery cell 20. On the other hand, it has higher safety in the process of welding the first inner circumferential surface 2141a of the shell 21 and the outer circumferential surface 231 of the end cover, and can reduce the welding deformation of the end cover 23 and the shell 21.

[0232] According to some embodiments of the present application, the present application further provides a battery 100 , which includes the battery cell 20 of any of the above solutions.

[0233] As shown in FIG. 2 , the battery 100 may further include a box body 10 , in which the battery cells 20 are accommodated.

[0234] In some embodiments, the box body 10 may include a first box body 11 and a second box body 12 . The first box body 11 and the second box body 12 cover each other, and the first box body 11 and the second box body 12 jointly define an assembly space for accommodating the battery cells 20 .

[0235] Optionally, the second box body 12 can be a hollow structure with one end open, and the first box body 11 can be a plate-like structure, and the first box body 11 covers the open side of the second box body 12, so that the first box body 11 and the second box body 12 jointly define an assembly space; the first box body 11 and the second box body 12 can also be hollow structures with one side open, and the open side of the first box body 11 covers the open side of the second box body 12.

[0236] Of course, the box body 10 formed by the first box body 11 and the second box body 12 can be in various shapes, such as a cylinder or a rectangular parallelepiped, etc. For example, in FIG2 , the box body 10 is a rectangular parallelepiped structure.

[0237] Optionally, the number of battery cells 20 disposed within the housing 10 may be one or more. For example, in FIG2 , the housing 10 of the battery 100 includes multiple battery cells 20, which may be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration refers to a configuration in which multiple battery cells 20 are connected in both series and parallel. Multiple battery cells 20 may be directly connected in series, in parallel, or in a hybrid configuration, and then the entire structure formed by the multiple battery cells 20 is housed within the housing 10. Alternatively, the battery 100 may comprise multiple battery cells 20 that are first connected in series, in parallel, or in a hybrid configuration to form a battery module, which is then further connected in series, in parallel, or in a hybrid configuration to form a single structure, which is then housed within the housing 10.

[0238] The battery 100 may further include other structures. For example, the battery 100 may further include a busbar component that connects the plurality of battery cells 20 to achieve electrical connection between the plurality of battery cells 20 .

[0239] It should be noted that in some embodiments, the battery 100 may not be provided with a housing 10. The battery 100 includes multiple battery cells 20, and the battery 100 composed of multiple battery cells 20 can be directly assembled on an electrical device to provide electrical energy to the electrical device through the multiple battery cells 20. In other words, the housing 10 can serve as part of the electrical device. Taking the vehicle 1000 as an example, the housing 10 can serve as part of the chassis structure of the vehicle 1000. For example, a portion of the housing 10 can form at least a portion of the floor of the vehicle 1000, or a portion of the housing 10 can form at least a portion of the crossbeam and longitudinal beam of the vehicle 1000.

[0240] According to some embodiments of the present application, the present application further provides an electrical device, which includes the battery cell 20 of any of the above solutions, and the battery cell 20 is used to provide electrical energy to the electrical device.

[0241] The electrical device may be any of the aforementioned devices or systems using the battery cell 20 .

[0242] According to some embodiments of the present application, as shown in Figures 3 to 7, the present application provides a battery cell 20, which includes a housing 21, an electrode assembly 22, an end cap 23, an electrode terminal 25, and two current collecting members 26. The housing 21 is cylindrical, with the central axis of the housing 21 extending along a first direction X. The housing 21 includes a sidewall 214 and a bottom wall 213. The sidewall 214 surrounds the bottom wall 213. One end of the sidewall 214 in the first direction X is connected to the bottom wall 213, and the other end encloses an opening 211. The end cap 23 closes the opening 211. The sidewall 214 includes a first sidewall 2141, a connecting wall 2142, and a second sidewall 2143 arranged in sequence and connected along the first direction X. The end of the first sidewall 2141 away from the connecting wall 2142 encloses the opening 211, and the end of the second sidewall 2143 away from the connecting wall 2142 is connected to the bottom wall 213. The inner surface of the first side wall 2141 is a first inner circumferential surface 2141 a , the inner surface of the connecting wall 2142 is a blocking surface 2142 a , and the inner surface of the second side wall 2143 is a second inner circumferential surface 2143 a . The first inner circumferential surface 2141a, the blocking surface 2142a and the second inner circumferential surface 2143a are arranged in sequence and connected along the first direction X. The end of the first inner circumferential surface 2141a away from the blocking surface 2142a encloses an opening 211. The blocking surface 2142a is an annular structure extending along the circumference of the first inner circumferential surface 2141a. The first inner circumferential surface 2141a is laser welded to the outer circumferential surface 231 of the end cover to form a weld mark 24. Along the first direction X, at least part of the projection of the weld mark 24 is located inside the blocking surface 2142a. The projection of the second inner circumferential surface 2143a is located on the inner side of the first inner circumferential surface 2141a, and the first inner circumferential surface 2141a is parallel to the second inner circumferential surface 2143a. The projection of the outer circumferential surface 2143b of the second side wall is located on the inner side of the outer circumferential surface 2141b of the first side wall. Along the first direction X, the dimension of the first inner circumferential surface 2141a is D1, satisfying 0.2 mm ≤ D1 ≤ 3.2 mm. Along the radial direction Y of the first inner circumferential surface, the minimum distance between the first inner circumferential surface 2141a and the second inner circumferential surface 2143a is D2, satisfying 0.1 mm ≤ D2 ≤ 1.2 mm. The thickness of the first sidewall 2141 is D3, and the thickness of the second sidewall 2143 is D4, satisfying 1 > D3 / D4 ≥ 0.55. The end cap 23 has a first surface 232 facing the electrode assembly 22 in the first direction X. The first surface 232 is connected to the outer circumferential surface 231 of the end cap via a transition surface 233, which abuts the blocking surface 2142a. The transition surface 233 includes a first rounded surface, and the blocking surface 2142a includes a second rounded surface. The second rounded surface mates with the first rounded surface and is in contact with each other.The housing 21 has a first end surface 215 at one end thereof, which forms an opening 211 in the first direction X. The first end surface 215 is connected to the first inner circumferential surface 2141a. The end cap 23 has a second surface 234 facing away from the electrode assembly 22 in the first direction X. The second surface 234 is connected to the outer circumferential surface 231 of the end cap and is coplanar with the first end surface 215. The end cap 23 has a protrusion 236 extending from the second surface 234 in the first direction X. The protrusion 236 forms a third surface 235 on the side facing away from the electrode assembly 22 in the first direction X. The third surface 235 is further away from the electrode assembly 22 than the second surface 234 in the first direction X. A first recess 237 is formed on the first surface 232 at a position corresponding to the protrusion 236. A distance D5 between the third surface 235 and the second surface 234 in the first direction X satisfies the condition 0.1 mm ≤ D5 ≤ 0.6 mm. The electrode assembly 22 is housed within the housing 21. Two tabs 221 are formed at either end of the electrode assembly 22 in the first direction X, with opposite polarities. An electrode terminal 25 is insulated and mounted on the bottom wall 213. Two current collecting members 26 are disposed within the housing 21, one on either side of the electrode assembly 22 along the first direction X. One current collecting member 26 connects the electrode terminal 25 to one tab 221 of the electrode assembly 22, while the other current collecting member 26 connects the end cap 23 to the other tab 221 of the electrode assembly 22, thereby electrically connecting the electrode assembly 22 to the electrode terminal 25 and the end cap 23.

[0243] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0244] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A battery cell, comprising: The housing has an opening formed at at least one end in the first direction; an electrode assembly, housed in the housing; as well as an end cap for closing the opening; In which, the inner surface of the shell includes a first inner circumferential surface and a blocking surface arranged and connected along the first direction, the first inner circumferential surface encloses one end away from the blocking surface to form the opening, the first inner circumferential surface is welded to the outer circumferential surface of the end cover to form a weld mark, and along the first direction, at least part of the projection of the weld mark is located within the blocking surface.

2. The battery cell according to claim 1, wherein: The blocking surface is an annular structure extending along the circumference of the first inner circumferential surface.

3. The battery cell according to claim 1 or 2, wherein: Along the first direction, the size of the first inner circumferential surface is D1, which satisfies 0.2 mm ≤ D1 ≤ 3.2 mm.

4. The battery cell according to any one of claims 1 to 3, wherein: The inner surface of the shell further includes a second inner circumferential surface, the first inner circumferential surface, the blocking surface and the second inner circumferential surface are arranged along the first direction, and the blocking surface connects the first inner circumferential surface and the second inner circumferential surface; The projection of the second inner circumferential surface in the first direction is located inside the first inner circumferential surface.

5. The battery cell according to claim 4, wherein: The first inner circumferential surface is parallel to the second inner circumferential surface.

6. The battery cell according to claim 4 or 5, wherein: Along the radial direction of the first inner circumferential surface, the minimum distance between the first inner circumferential surface and the second inner circumferential surface is D2, satisfying 0.1 mm ≤ D2 ≤ 1.2 mm.

7. The battery cell according to any one of claims 4 to 6, wherein: The housing comprises: a side wall surrounding the outer side of the electrode assembly, the opening being formed at at least one end of the side wall in the first direction, the side wall comprising a first side wall, a connecting wall, and a second side wall sequentially arranged and connected along the first direction, the inner surface of the first side wall being the first inner circumferential surface, the inner surface of the connecting wall being the blocking surface, and the inner surface of the second side wall being the second inner circumferential surface; Wherein, along the first direction, a projection of the outer circumferential surface of the second side wall is located on the inner side of the outer circumferential surface of the first side wall.

8. The battery cell according to claim 7, wherein: The wall thickness of the first side wall is smaller than the wall thickness of the second side wall.

9. The battery cell according to claim 8, wherein: The wall thickness of the first side wall is D3, and the wall thickness of the second side wall is D4, satisfying 1>D3 / D4≥0.

55.

10. The battery cell according to any one of claims 4 to 6, wherein: The housing comprises: a side wall surrounding the outer side of the electrode assembly, the opening being formed at at least one end of the side wall in the first direction, the side wall comprising a first side wall, a connecting wall, and a second side wall sequentially arranged and connected along the first direction, the inner surface of the first side wall being the first inner circumferential surface, the inner surface of the connecting wall being the blocking surface, and the inner surface of the second side wall being the second inner circumferential surface; The outer peripheral surface of the second side wall is coplanar with the outer peripheral surface of the first side wall.

11. The battery cell according to any one of claims 1 to 10, wherein: Along the first direction, the end cover abuts against the blocking surface.

12. The battery cell according to claim 11, wherein: The end cover has a first surface facing the electrode assembly in the first direction, the first surface is connected to the outer peripheral surface of the end cover via a transition surface, and the transition surface abuts against the blocking surface.

13. The battery cell according to claim 12, wherein: The transition surface includes a first rounded surface, and the blocking surface includes a second rounded surface. The second rounded surface fits with the first rounded surface and adheres to each other.

14. The battery cell according to any one of claims 1 to 13, wherein: The end of the shell forming the opening in the first direction has a first end surface, the first end surface is connected to the first inner circumferential surface, and the end cover has a second surface facing away from the electrode assembly in the first direction, the second surface is connected to the outer circumferential surface of the end cover, and the second surface is coplanar with the first end surface.

15. The battery cell according to claim 14, wherein: Along the first direction, the end cap has a third surface farthest from the electrode assembly, and the third surface is farther from the electrode assembly than the second surface.

16. The battery cell according to claim 15, wherein: The end cap is formed with a protrusion protruding from the second surface along the first direction, and a side of the protrusion facing away from the electrode assembly in the first direction forms the third surface.

17. The battery cell according to claim 16, wherein: Along the first direction, a distance D5 between the third surface and the second surface satisfies 0.1 mm ≤ D5 ≤ 0.6 mm.

18. The battery cell according to claim 16 or 17, wherein: The end cap has a first surface facing the electrode assembly in the first direction; Wherein, along the first direction, a first groove is formed on the first surface at a position corresponding to the protrusion.

19. The battery cell according to any one of claims 14 to 18, wherein: The second surface is provided with a second groove, which is an annular groove extending along the circumference of the first inner peripheral surface.

20. The battery cell according to any one of claims 1 to 19, wherein: The shell is cylindrical, and the central axis of the shell extends along the first direction.

21. The battery cell according to any one of claims 1 to 20, wherein: The first inner circumferential surface is laser welded to the outer circumferential surface of the end cover.

22. A battery comprising the battery cell according to any one of claims 1 to 21.

23. An electrical device comprising the battery cell according to any one of claims 1 to 21, wherein the battery cell is used to provide electrical energy.

Images