Battery cell, battery and electric device

Abstract

A battery cell (20), a battery (100) and an electric device, belonging to the technical field of batteries. The battery cell (20) comprises a casing (21) and an end cap (22). An accommodating cavity (211) is formed inside the casing (21), at least one end of the accommodating cavity (211) in a first direction (X) having an opening (211) formed thereon, and the accommodating cavity (211) being used for accommodating an electrode assembly (23). The end cap (22) comprises a first cap body (221) and a second cap body (222) stacked in the first direction (X), wherein the first cap body (221) is connected to the casing (21) thus sealing the opening (212), and the strength of the second cap body (222) is greater than the strength of the first cap body (221). By setting the strength of the second cap body (222) to be greater than the strength of the first cap body (221), the end cap (22) of said structure is provided with the second cap body (222) having a higher strength on one side of the first cap body (221), enabling the overall structural strength of the end cap (22) to be improved; thus, while remaining the same structural strength of the end cap (22), the mutual connection between the end cap (22) and the casing (21) can be realized by means of the first cap body (221), and the overall thickness of the first cap body (221) and second cap body (222) of the end cap (22) stacked in the first direction (X) can also be optimized.

Description

Battery cells, batteries and electrical devices Technical Field

[0001] 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

[0002] New energy vehicles have experienced rapid growth in recent years. Within the electric vehicle sector, power batteries, as the power source, play an irreplaceable and important role. With the vigorous promotion of new energy vehicles, demand for power battery products is also growing. As core components of new energy vehicles, batteries have high performance requirements. A battery cell typically consists of a housing and an electrode assembly housed within it. However, existing battery cells have low internal space utilization, hindering their energy density.

[0003] Summary of the Invention

[0004] The embodiments of the present application provide a battery cell, a battery, and an electrical device, which can effectively improve the energy density of the battery cell.

[0005] In a first aspect, an embodiment of the present application provides a battery cell comprising a shell and an end cover; a accommodating cavity is formed inside the shell, an opening is formed at at least one end of the accommodating cavity in a first direction, and the accommodating cavity is used to accommodate an electrode assembly; the end cover closes the opening; wherein the end cover comprises a first cover body and a second cover body stacked along the first direction, the first cover body being connected to the shell to close the opening, and the strength of the second cover body is greater than that of the first cover body.

[0006] In the above technical solution, the end cover of the battery cell is provided with a first cover body and a second cover body stacked along a first direction, and the first cover body is used to be connected to the shell to realize that the end cover closes the opening of the shell. By setting the strength of the second cover body to be greater than the strength of the first cover body, the end cover of this structure is provided with a second cover body with higher strength on one side of the first cover body, thereby improving the overall structural strength of the end cover, so that under the end covers of the same structural strength, the end cover can be connected to the shell through the first cover body, and the overall thickness of the first cover body and the second cover body of the end cover after being stacked on each other in the first direction can be optimized, thereby satisfying the structural strength of the end cover, realizing the mutual assembly connection between the end cover and the shell, and effectively improving the space utilization rate of the battery cell, thereby improving the energy density of the battery cell.

[0007] In some embodiments, the strength of the first cover is T1, and the strength of the second cover is T2, satisfying T2-T1≥150 MPa.

[0008] In the above technical solution, by setting the strength of the second cover body to be greater than or equal to 150 MPa than the strength of the first cover body, the strength of the second cover body can be further improved when the first cover body is connected to the shell, thereby further reducing the space occupied by the first cover body and the second cover body in the first direction under the end cover of the same structural strength, which is beneficial to further improve the space utilization of the battery cell and thus improve the energy density of the battery cell.

[0009] In some embodiments, along the first direction, the first cover body has a first surface facing the second cover body, and the first surface is protruding with a first abutment portion, which surrounds the outer side of the second cover body, and the outer peripheral surface of the first abutment portion abuts against the inner peripheral surface of the shell.

[0010] In the above technical solution, a first abutment portion is protruded on the first surface of the first cover body, the outer peripheral surface of the first abutment portion abuts against the inner peripheral surface of the shell, and the first abutment portion is a structure surrounding the outer side of the second cover body. The end cover with this structure can further increase the contact area between the first cover body and the shell without increasing the thickness of the first cover body and the second cover body stacked on each other, thereby facilitating improving the structural stability and reliability of the end cover assembled on the shell through the first cover body.

[0011] In some embodiments, the outer circumferential surface of the second cover body abuts against the inner circumferential surface of the first abutting portion.

[0012] In the above technical solution, by setting the outer peripheral surface of the second cover body to abut against the inner peripheral surface of the first abutting portion, on the one hand, the structural stability of the second cover body assembled on the inner side of the first abutting portion can be improved, and on the other hand, the second cover body can also provide a certain support effect for the first abutting portion to improve the structural stability of the outer peripheral surface of the first abutting portion abutting against the inner peripheral surface of the shell, which is conducive to alleviating the deformation of the first abutting portion.

[0013] In some embodiments, along the first direction, the second cover body has a second surface facing away from the first cover body, and the second surface is protruding with a second abutment portion, which is an annular structure extending along the circumference of the first abutment portion, and the outer circumferential surface of the second abutment portion abuts against the inner circumferential surface of the first abutment portion.

[0014] In the above technical solution, a second abutment portion with an annular structure is protruded on the second surface of the second cover body, and the outer peripheral surface of the second abutment portion abuts against the inner peripheral surface of the first abutment portion, so that the contact area between the second cover body and the inner peripheral surface of the first abutment portion can be increased by the second abutment portion without increasing the thickness of the first cover body and the second cover body stacked on each other, which is beneficial to further enhance the supporting effect of the second cover body on the first abutment portion, and further enhance the structural stability of the abutment of the outer peripheral surface of the first abutment portion against the inner peripheral surface of the shell, so as to further alleviate the deformation of the first abutment portion.

[0015] In some embodiments, along the first direction, the first abutting portion has a first end surface facing away from the first surface, the second abutting portion has a second end surface facing away from the second surface, and the second end surface is flush with the first end surface.

[0016] In the above technical solution, by setting the first end face of the first abutment portion facing away from the first surface to a structure that is flush with the second end face of the second abutment portion facing away from the second surface, on the one hand, the contact area between the first abutment portion and the second abutment portion can be further increased to enhance the supporting effect of the second cover body on the first abutment portion, and on the other hand, the phenomenon of space waste of the battery cell caused by the second abutment portion protruding from the first end face can be effectively alleviated.

[0017] In some embodiments, the second cover and the second abutting portion are integrally formed.

[0018] In the above technical solution, by setting the second cover body and the second abutment part as an integrally formed structure, it is beneficial to improve the structural strength and structural stability between the second cover body and the second abutment part, so as to reduce the risk of separation between the second abutment part and the second cover body.

[0019] In some embodiments, an inner circumferential surface of the first abutting portion is parallel to the first direction.

[0020] In the above technical solution, by setting the inner circumferential surface of the first abutment portion to a structure parallel to the first direction, it is convenient to assemble the second cover body to the inner side of the first abutment portion along the first direction, and it is convenient for the outer circumferential surface of the first cover body and the inner circumferential surface of the first abutment portion to abut each other, which is beneficial to reduce the assembly difficulty between the second cover body and the first cover body, and thus can improve the production efficiency of the battery cell.

[0021] In some embodiments, the outer circumferential surface of the first cover abuts against the inner circumferential surface of the shell.

[0022] In the above technical solution, by abutting the outer peripheral surface of the first cover body against the inner peripheral surface of the shell, the outer peripheral surfaces of the first cover body and the first abutting portion are both structures abutting against the inner peripheral surface of the shell, thereby further improving the stability and reliability of the mutual assembly connection between the first cover body and the shell.

[0023] In some embodiments, the outer circumference of the first cover is flush with the outer circumference of the first abutting portion, and the outer circumference of the first cover and the outer circumference of the first abutting portion together form a welding surface, which is welded to the inner circumference of the shell.

[0024] In the above technical solution, the outer peripheral surface of the first cover body and the outer peripheral surface of the first abutment portion are set to be flush with each other and jointly define a welding surface that is welded to the inner peripheral surface of the shell, so that the end cover is a structure in which the first cover body and the first abutment portion surrounding the outer side of the second cover body are welded to the shell, thereby effectively increasing the welding area between the end cover and the shell, so that after the thickness of the first cover body of the end cover is reduced, there is enough area to be welded to the shell, so that under the end cover of the same strength, the area size of the area where the first cover body of the end cover and the shell are connected to each other can be met, and the thickness of the first cover body and the second cover body of the end cover stacked on each other in the first direction can be optimized, thereby meeting the structural strength of the end cover while improving the reliability of the connection interface between the end cover and the shell and effectively improving the space utilization rate of the battery cell.

[0025] In some embodiments, along the first direction, the shell is provided with a third end face formed at one end of the opening, and the third end face is connected to the inner circumferential surface of the shell; wherein, along the first direction, the third end face is arranged facing the first surface, and the third end face is connected to the first surface.

[0026] In the above technical solution, by arranging the third end face of the shell and the first surface of the first cover body to face each other and be connected, the outer edge of the first cover body is a structure that protrudes from the outer peripheral surface of the first abutment portion, so that the end cover can not only abut against the inner peripheral surface of the shell through the first abutment portion, but also be connected to the third end face of the shell through the first surface of the first cover body, thereby enabling the end cover to contact the shell from multiple different directions, which is beneficial to further improve the assembly reliability and structural stability between the end cover and the shell.

[0027] In some embodiments, the third end surface is connected to the first surface by welding.

[0028] In the above technical solution, by welding the third end face of the shell and the first surface of the first cover body to each other, the outer edge of the first cover body protruding from the outer peripheral surface of the first abutment portion is a structure welded to the shell, which is beneficial to improving the connection strength between the first cover body and the shell.

[0029] In some embodiments, the first cover and the first abutting portion are integrally formed.

[0030] In the above technical solution, by setting the first cover body and the first abutment part as an integrally formed structure, on the one hand, the structural strength and structural stability between the first cover body and the first abutment part can be effectively improved to reduce the risk of mutual separation between the first abutment part and the first cover body; on the other hand, it is convenient to set the first cover body and the first abutment part as a structure of the same material, thereby facilitating the welding connection between the first cover body and the first abutment part and the shell.

[0031] In some embodiments, along the first direction, the second cover is located on a side of the first cover facing the accommodating cavity.

[0032] In the above technical solution, by setting the second cover body to be located on the side of the first cover body facing the accommodating cavity, the second cover body is a structure located on the inner side of the first cover body, so that the second cover body is thinned after the first cover body is connected to the shell, which can save the space occupied by the end cover inside the battery cell, which is beneficial to improving the internal space utilization of the battery cell.

[0033] In some embodiments, along the first direction, the second cover is located on a side of the first cover facing away from the accommodating cavity.

[0034] In the above technical solution, by arranging the second cover body to be located on the side of the first cover body away from the accommodating cavity, the second cover body is a structure located on the outside of the first cover body, thereby facilitating the assembly of the second cover body onto the first cover body, and after the first cover body is connected to the shell, the interference effect of the second cover body on other components inside the battery cell can be reduced.

[0035] In some embodiments, the first cover is connected to the housing by welding.

[0036] In the above technical solution, by setting the first cover body and the shell to be welded to each other, it is beneficial to improve the connection strength between the first cover body and the shell, thereby effectively improving the structural stability and reliability of the end cover assembled to the shell.

[0037] In some embodiments, the material of the first cover is the same as that of the housing.

[0038] In the above technical solution, by setting the material of the first cover body to be the same as the material of the shell, it is possible to achieve a structure in which the first cover body and the shell are welded with the same material. On the one hand, it can reduce the difficulty of welding between the first cover body and the shell, and on the other hand, it can reduce the occurrence of cold welding or welding failure between the first cover body and the shell, which is beneficial to improving the welding quality between the first cover body and the shell.

[0039] In some embodiments, the material of the first cover includes aluminum or aluminum alloy, and the material of the second cover includes steel.

[0040] In the above technical solution, by setting the material of the first cover body to aluminum or aluminum alloy and correspondingly setting the material of the second cover body to steel, on the one hand, the manufacturing cost of the end cover can be reduced, and on the other hand, the strength of the second cover body is made much higher than the strength of the first cover body. Therefore, under the end cover of the same structural strength, the thickness of the first cover body and the second cover body stacked on each other along the first direction can be further optimized, which is conducive to further improving the space utilization of the battery cell.

[0041] In some embodiments, the first cover and the second cover are compositely connected.

[0042] In the above technical solution, the composite connection structure is used to connect the first cover and the second cover, which can effectively improve the structural strength and connection stability of the first cover and the second cover, and is conducive to reducing the risk of separation between the first cover and the second cover.

[0043] In a second aspect, an embodiment of the present application further provides a battery comprising the above-mentioned battery cell.

[0044] 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

[0045] 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.

[0046] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0047] FIG2 is an exploded view of the structure of a battery provided in some embodiments of the present application;

[0048] FIG3 is a schematic structural diagram of a battery cell provided in some embodiments of the present application;

[0049] FIG4 is an exploded view of the structure of a battery cell provided in some embodiments of the present application;

[0050] FIG5 is a cross-sectional view of an end cap of a battery cell provided in some embodiments of the present application;

[0051] FIG6 is a partial enlarged view of point A of the end cover shown in FIG5 ;

[0052] FIG7 is a partial cross-sectional view of a battery cell provided in some embodiments of the present application;

[0053] FIG8 is a cross-sectional view of an end cover of a battery cell provided in some other embodiments of the present application;

[0054] FIG9 is a partial enlarged view of point B of the end cap shown in FIG8 ;

[0055] FIG10 is a partial cross-sectional view of a battery cell provided in some other embodiments of the present application;

[0056] FIG11 is a cross-sectional view of an end cover of a battery cell provided in some further embodiments of the present application;

[0057] FIG12 is a partial enlarged view of point C of the end cap shown in FIG11;

[0058] FIG13 is a partial cross-sectional view of a battery cell provided in some other embodiments of the present application;

[0059] FIG14 is a cross-sectional view of an end cap of a battery cell provided in some other embodiments of the present application;

[0060] FIG15 is a partial enlarged view of point D of the end cap shown in FIG14;

[0061] FIG16 is a partial cross-sectional view of a battery cell provided in some other embodiments of the present application.

[0062] Icon: 1000-vehicle; 100-battery; 10-casing; 11-first casing body; 12-second casing body; 20-battery cell; 21-casing; 211-accommodation chamber; 212-opening; 213-third end face; 22-end cover; 221-first cover; 2211-first surface; 2212-first abutment; 2212a-first end face; 2213-welding surface; 222-second cover; 2221-second surface; 2222-second abutment; 2222a-second end face; 23-electrode assembly; 231-ear; 24-electrode terminal; 25-current collecting member; 26-pressure relief mechanism; 200-controller; 300-motor; X-first direction. 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 0.05 O2) 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 folded segments that are stacked.

[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 that is used to encapsulate components such as an electrode assembly and an electrolyte.

[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, including performance parameters such as energy density, cycle life, discharge capacity, and charge / discharge rate. Furthermore, battery safety must also be considered.

[0113] For a general battery cell, the battery cell usually includes an outer shell and an electrode assembly contained in the outer shell. The outer shell includes a shell and an end cap. The interior of the shell forms a receiving cavity with an opening, which is used to accommodate the electrode assembly. The end cap covers the opening and is connected to the shell. In order to reduce the difficulty of assembly and improve the assembly quality, the relevant technology usually sets the material of the end cap to be the same as that of the shell, and the end cap is welded to the shell to seal the opening of the shell. However, in order to improve the structural strength of the end cap and ensure the welding reliability between the end cap and the shell, the thickness of the end cap needs to be increased, resulting in the end cap occupying more space, resulting in low internal space utilization of the battery cell, which is not conducive to improving the energy density of the battery cell.

[0114] Based on the above considerations, and to address the issue of low internal space utilization within a battery cell, an embodiment of the present application provides a battery cell comprising a housing and an end cap. The housing has a housing formed therein, the housing having an opening formed at at least one end thereof in a first direction, the housing being configured to accommodate an electrode assembly. The end cap seals the opening. The end cap comprises a first cover body and a second cover body stacked along the first direction, the first cover body being connected to the housing to seal the opening, and the second cover body being stronger than the first cover body.

[0115] In a battery cell of this structure, the end cover of the battery cell is provided with a first cover body and a second cover body stacked along a first direction, and the first cover body is used to connect to the shell to achieve the end cover closing the opening of the shell. By setting the strength of the second cover body to be greater than the strength of the first cover body, the end cover of this structure is provided with a second cover body with higher strength on one side of the first cover body, thereby improving the overall structural strength of the end cover, so that under end covers of the same structural strength, the end cover can be connected to the shell through the first cover body, and the overall thickness of the first cover body and the second cover body of the end cover after being stacked on each other in the first direction can be optimized, thereby achieving the mutual assembly connection between the end cover and the shell while meeting the structural strength of the end cover, and effectively improving the space utilization rate of the battery cell to improve the energy density 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 an electrical device. This helps alleviate the problem of low internal space utilization within the battery cells and improves the energy density 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 multiple battery cells 20 to achieve electrical connection between the multiple battery cells 20. The busbar component plays the role of connecting multiple battery cells 20 in series, in parallel, or in hybrid connection. The material of the busbar component can be copper, iron, aluminum, steel, aluminum alloy, etc.

[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 rectangular parallelepiped.

[0127] According to some embodiments of the present application, referring to FIG3 and further to FIG4, FIG5, FIG6, and FIG7, FIG4 is an exploded view of the structure of a battery cell 20 provided in some embodiments of the present application, FIG5 is a cross-sectional view of an end cap 22 of a battery cell 20 provided in some embodiments of the present application, FIG6 is a partial enlarged view of a portion A of the end cap 22 shown in FIG5, and FIG7 is a partial cross-sectional view of a battery cell 20 provided in some embodiments of the present application. The present application provides a battery cell 20, comprising a housing 21 and an end cap 22. The housing 21 has an interior formed with a receiving cavity 211. The receiving cavity 211 has an opening 212 formed at at least one end thereof in a first direction X. The receiving cavity 211 is configured to accommodate an electrode assembly 23. The end cap 22 closes the opening 212. The end cap 22 includes a first cover 221 and a second cover 222 stacked along the first direction X. The first cover 221 is connected to the housing 21 to close the opening 212. The second cover 222 is stronger than the first cover 221.

[0128] Among them, the battery cell 20 can also include an electrode assembly 23, which is accommodated in the accommodating cavity 211 of the shell 21. The electrode assembly 23 is a component where electrochemical reactions occur in the battery cell 20. The structure of the electrode assembly 23 can be various. For example, the electrode assembly 23 can be a winding 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.

[0129] 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.

[0130] Optionally, there may be one or more electrode assemblies 23 housed within the housing cavity 211 of the housing 21. For example, in FIG4 , two electrode assemblies 23 are disposed within the housing 21 of the battery cell 20, and the two electrode assemblies 23 are stacked along the thickness direction of the housing 21. In other embodiments, there may be one, three, four, five, six, seven, or eight electrode assemblies 23 housed within the housing cavity 211 of the housing 21.

[0131] Optionally, the housing formed by the shell 21 and the end cap 22 can also be used to contain an electrolyte, such as an electrolyte solution. The housing formed by the shell 21 and the end cap 22 can have various structural forms, such as a cylinder or a rectangular parallelepiped. Similarly, the material of the shell 21 can also be various, such as aluminum or an aluminum alloy.

[0132] The housing 21 has an interior formed with a housing cavity 211. The housing cavity 211 has an opening 212 formed at at least one end in the first direction X. That is, the housing 21 is a hollow structure having an opening 212 formed at at least one end in the first direction X. The housing 21 may have an opening 212 formed at one end in the first direction X, or may have openings 212 formed at both ends in the first direction X. For example, in FIG4 , the housing 21 has an opening 212 formed at only one end in the first direction X, and the end cap 22 is fitted over the opening 212 of the housing 21 to form a sealed connection, thereby forming a sealed space for accommodating the electrode assembly 23 and the electrolyte.

[0133] The end cover 22 includes a first cover body 221 and a second cover body 222 stacked along the first direction X. That is, the end cover 22 is provided with the first cover body 221 and the second cover body 222 stacked and connected along the first direction X. It should be noted that, in the first cover body 221 and the second cover body 222 stacked in the first direction X, the second cover body 222 may be located on the side of the first cover body 221 facing the accommodating cavity 211, or the second cover body 222 may be located on the side of the first cover body 221 facing away from the accommodating cavity 211.

[0134] The connection structure between the first cover 221 and the second cover 222 can be various, such as bonding, bolting, composite connection or welding, etc. For example, in the embodiment of the present application, the first cover 221 and the second cover 222 are compositely connected, such as hot pressing or cold pressing, etc.

[0135] The first cover 221 is connected to the housing 21 to close the opening 212 . That is, the first cover 221 of the end cover 22 is connected to the housing 21 and closes the opening 212 of the housing 21 .

[0136] The strength of the second cover 222 is greater than that of the first cover 221, that is, the metal material strength of the second cover 222 is greater than the metal material strength of the second cover 222. It should be noted that the strength of the first cover 221 and the strength of the second cover 222 refer to the mechanical properties of the engineering materials of the first cover 221 and the second cover 222, which indicate their ability to resist fracture and excessive deformation. To determine the strength of the first cover 221 and the second cover 222, a static load test can be performed to test the strength of the first cover 221 and the second cover 222.

[0137] The first cover 221 serves to connect the housing 21 . For example, the first cover 221 and the housing 21 are made of aluminum or aluminum alloy. Correspondingly, the second cover 222 can be made of steel or nickel.

[0138] When assembling the battery cell 20 , the electrode assembly 23 may be placed in the housing 21 first, and the housing 21 may be filled with electrolyte. The end cap 22 may then be placed on the opening 212 of the housing 21 to complete the assembly of the battery cell 20 .

[0139] The housing 21 can have a variety of shapes, such as a cylinder, a rectangular parallelepiped, or a prismatic structure. The shape of the housing 21 can be determined based on the specific shape of the electrode assembly 23. For example, if the electrode assembly 23 has a cylindrical structure, a housing 21 with a cylindrical structure can be selected; if the electrode assembly 23 has a rectangular parallelepiped structure, a housing 21 with a rectangular parallelepiped structure can be selected. Of course, the structure of the end cap 22 can also be various, such as a plate-like structure or a hollow structure with one end open. For example, in Figure 4, the housing 21 has a rectangular parallelepiped structure and the end cap 22 has a plate-like structure.

[0140] Of course, it is understandable that the battery cell 20 is not limited to the above structure. The battery cell 20 can also be other structures. For example, the battery cell 20 can include a shell 21 and two end covers 22. The shell 21 is a hollow structure with openings 212 on both sides opposite to each other in the first direction X. One end cover 22 corresponds to an opening 212 of the shell 21 and forms a sealed connection to form a sealed space for accommodating the electrode assembly 23 and the electrolyte. That is, the shell 21 has openings 212 on both sides opposite to each other, and the two end covers 22 are respectively covered on both sides of the shell 21 to close the corresponding openings 212.

[0141] In some embodiments, as shown in Figures 3 and 4, the battery cell 20 may further include an electrode terminal 24, which is insulated and mounted on the end cover 22 and electrically connected to the electrode assembly 23 to output or input electrical energy of the battery cell 20.

[0142] It should be noted that the electrode terminal 24 is insulated and mounted on the end cap 22, that is, there is no electrical connection between the electrode terminal 24 and the end cap 22. Of course, in other embodiments, the electrode terminal 24 may also be disposed on the housing 21.

[0143] Exemplarily, the electrode terminal 24 may be made of various materials. For example, the electrode terminal 24 may be made of copper, iron, aluminum, steel, or aluminum alloy.

[0144] In Figures 3 and 4 , the battery cell 20 includes two electrode terminals 24. Correspondingly, each electrode assembly 23 has two tabs 231 with opposite polarities. The two electrode terminals 24 are electrically connected to the two tabs 231 of the electrode assembly 23, respectively, to enable input or output of the positive and negative electrodes of the battery cell 20. It should be noted that the tabs 231 of the electrode assembly 23 are formed by stacking and connecting the regions of the positive electrode sheets not coated with the positive active material layer, or by stacking and connecting the regions of the negative electrode sheets not coated with the negative active material layer. If the tabs 231 are used to output the positive electrode of the electrode assembly 23, then the tabs 231 are formed by stacking and connecting the regions of the positive electrode sheets not coated with the positive active material layer. If the tabs 231 are used to output the negative electrode of the electrode assembly 23, then the tabs 231 are formed by stacking and connecting the regions of the negative electrode sheets not coated with the negative active material layer.

[0145] For example, in Figures 3 and 4 , both electrode terminals 24 are mounted on the end cap 22. Of course, the structure of the battery cell 20 is not limited thereto. In other embodiments, both electrode terminals 24 may be mounted on the housing 21. Similarly, one electrode terminal 24 may be mounted on the housing 21, and the other electrode terminal 24 may be mounted on the end cap 22.

[0146] In some embodiments, as shown in Figure 4, the battery cell 20 may also include a current collecting component 25, which is arranged in the accommodating cavity 211 of the shell 21. The current collecting component 25 connects the electrode terminal 24 and the pole ear 231 of the electrode assembly 23 to achieve electrical connection between the electrode assembly 23 and the electrode terminal 24, thereby reducing the difficulty of assembling between the electrode terminal 24 and the pole ear 231 of the electrode assembly 23.

[0147] Illustratively, the current collecting member 25 is welded to the electrode terminal 24 and to the tab 231. Of course, in other embodiments, the current collecting member 25 may be in contact with or bonded to the electrode terminal 24, and similarly, the current collecting member 25 may be in contact with or bonded to the tab 231.

[0148] The current collecting member 25 connects the electrode terminal 24 and the tab 231 of the electrode assembly 23 . The current collecting member 25 can be made of various materials, for example, copper, iron, aluminum, steel, or aluminum alloy.

[0149] In Figure 4, the battery cell 20 includes two electrode terminals 24 and two current collecting members 25. Correspondingly, each electrode assembly 23 has two pole tabs 231, and the polarities of the two pole tabs 231 are opposite. The two electrode terminals 24 are electrically connected to the two pole tabs 231 of the electrode assembly 23 through the two current collecting members 25 to realize the input or output of the positive and negative electrodes of the battery cell 20.

[0150] In some embodiments, as shown in Figures 3 and 4 , the battery cell 20 may further include a pressure relief mechanism 26 disposed on the end cap 22. The pressure relief mechanism 26 is configured to relieve pressure within the battery cell 20 when the internal pressure or temperature of the battery cell 20 reaches a predetermined value. Of course, in other embodiments, the pressure relief mechanism 26 may also be disposed on the housing 21.

[0151] Optionally, the pressure relief mechanism 26 and the end cap 22 may be integrally formed or separately formed. For example, in FIG4 , the pressure relief mechanism 26 and the end cap 22 are separate structures, and the pressure relief mechanism 26 may be connected to the end cap 22 by welding or other methods. Accordingly, the pressure relief mechanism 26 may be a pressure relief component such as an explosion-proof valve, an explosion-proof disk, an air valve, a pressure relief valve, or a safety valve. Of course, in other embodiments, the pressure relief mechanism 26 and the end cap 22 may also be integrally formed, in which case the pressure relief mechanism 26 is a region of the end cap 22 where a weak structure is formed, such as a region of the end cap 22 where a notched groove is provided.

[0152] In this embodiment, the end cover 22 of the battery cell 20 is provided with a first cover body 221 and a second cover body 222 stacked along the first direction X, and the first cover body 221 is used to be connected to the shell 21 to enable the end cover 22 to close the opening 212 of the shell 21. By setting the strength of the second cover body 222 to be greater than the strength of the first cover body 221, the end cover 22 of this structure is provided with a second cover body 222 with higher strength on one side of the first cover body 221, thereby improving the overall structural strength of the end cover 22. Under the condition of the end cover 22 having the same structural strength, the end cover 22 can be connected to the shell 21 through the first cover body 221, and the overall thickness of the first cover body 221 and the second cover body 222 of the end cover 22 after being stacked on each other in the first direction X can be optimized. Therefore, under the condition of satisfying the structural strength of the end cover 22, the mutual assembly connection between the end cover 22 and the shell 21 can be achieved, and the space utilization rate of the battery cell 20 can be effectively improved, thereby improving the energy density of the battery cell 20.

[0153] According to some embodiments of the present application, the strength of the first cover body 221 is T1, and the strength of the second cover body 222 is T2, satisfying T2-T1≥150MPa.

[0154] Optionally, the strength of the second cover body 222 may be 150 MPa, 160 MPa, 180 MPa, 200 MPa, 250 MPa, 300 MPa, 350 MPa, 400 MPa, 450 MPa, 500 MPa, 600 MPa, 700 MPa, 800 MPa or 900 MPa greater than the strength of the first cover body 221 .

[0155] Exemplarily, the material of the first cover 221 is aluminum or aluminum alloy, and correspondingly, the material of the second cover 222 can be steel or nickel.

[0156] In this embodiment, by setting the strength of the second cover body 222 to be greater than or equal to 150 MPa than the strength of the first cover body 221, the strength of the second cover body 222 can be further improved when the first cover body 221 is connected to the shell 21, so that under the end cover 22 of the same structural strength, the space occupied by the first cover body 221 and the second cover body 222 in the first direction X can be further reduced, which is beneficial to further improve the space utilization of the battery cell 20 and thereby improve the energy density of the battery cell 20.

[0157] According to some embodiments of the present application, referring to Figures 6 and 7, along the first direction X, the first cover body 221 has a first surface 2211 facing the second cover body 222, and the first surface 2211 is protrudingly provided with a first abutting portion 2212, which surrounds the outer side of the second cover body 222, and the outer peripheral surface of the first abutting portion 2212 abuts against the inner peripheral surface of the shell 21.

[0158] The first cover 221 has a first surface 2211 facing the second cover 222 , that is, the surface of the first cover 221 facing the second cover 222 and in contact with the second cover 222 is the first surface 2211 .

[0159] A first abutting portion 2212 is protruded from the first surface 2211, and the first abutting portion 2212 surrounds the outer side of the second cover body 222. That is, the first abutting portion 2212 is connected to the first surface 2211, and the first abutting portion 2212 is an annular structure arranged around the second cover body 222, so that the second cover body 222 is located on the inner side of the first abutting portion 2212.

[0160] The outer circumferential surface of the first abutting portion 2212 abuts against the inner circumferential surface of the housing 21 , that is, the outer circumferential side of the first abutting portion 2212 abuts against the inner surface of the housing 21 facing the accommodating cavity 211 .

[0161] It should be noted that the first cover body 221 and the first abutment portion 2212 can be an integrally formed structure, that is, the first cover body 221 and the first abutment portion 2212 are an integral structure, and the first cover body 221 and the first abutment portion 2212 can be made by an integral forming process such as stamping, casting, bending or milling. Of course, the first cover body 221 and the first abutment portion 2212 can also be a separately set structure, that is, the first cover body 221 and the first abutment portion 2212 are a split structure, and the first abutment portion 2212 can be connected to the first surface 2211 of the first cover body 221 by welding, bolting or bonding.

[0162] In this embodiment, a first abutting portion 2212 is protruded on the first surface 2211 of the first cover body 221, and the outer peripheral surface of the first abutting portion 2212 abuts against the inner peripheral surface of the shell 21, and the first abutting portion 2212 is a structure that surrounds the outer side of the second cover body 222. The end cover 22 with this structure can further increase the contact area between the first cover body 221 and the shell 21 without increasing the thickness of the first cover body 221 and the second cover body 222 stacked on each other, thereby facilitating the improvement of the structural stability and reliability of the end cover 22 assembled on the shell 21 through the first cover body 221.

[0163] 6 and 7 , the outer circumference of the second cover 222 abuts against the inner circumference of the first abutting portion 2212. In other words, the outer circumference of the second cover 222 and the inner circumference of the first abutting portion 2212 abut against each other.

[0164] In this embodiment, by setting the outer peripheral surface of the second cover body 222 to abut against the inner peripheral surface of the first abutting portion 2212, on the one hand, the structural stability of the second cover body 222 assembled on the inner side of the first abutting portion 2212 can be improved, and on the other hand, the second cover body 222 can also provide a certain support for the first abutting portion 2212 to improve the structural stability of the outer peripheral surface of the first abutting portion 2212 abutting against the inner peripheral surface of the shell 21, which is conducive to alleviating the deformation of the first abutting portion 2212.

[0165] According to some embodiments of the present application, referring to Figures 8, 9, and 10, Figure 8 is a cross-sectional view of the end cap 22 of a battery cell 20 provided in further embodiments of the present application, Figure 9 is a partial enlarged view of a portion B of the end cap 22 shown in Figure 8, and Figure 10 is a partial cross-sectional view of a battery cell 20 provided in further embodiments of the present application. Along a first direction X, the second cover 222 has a second surface 2221 facing away from the first cover 221. A second abutting portion 2222 is protruding from the second surface 2221. The second abutting portion 2222 is an annular structure extending along the circumference of the first abutting portion 2212, with the outer circumferential surface of the second abutting portion 2222 abutting the inner circumferential surface of the first abutting portion 2212.

[0166] The second cover 222 has a second surface 2221 facing away from the first cover 221 , that is, a surface of the second cover 222 facing away from the first cover 221 in the first direction X and not in contact with the first cover 221 is the second surface 2221 .

[0167] The second surface 2221 is provided with a protruding second abutment portion 2222, which is an annular structure extending along the circumference of the first abutment portion 2212, and the outer circumferential surface of the second abutment portion 2222 abuts against the inner circumferential surface of the first abutment portion 2212. That is, the second abutment portion 2222 is an annular structure connected to the second surface 2221, and the outer circumferential side of the second abutment portion 2222 abuts against the inner circumferential side of the first abutment portion 2212, that is, the outer circumferential surface of the second abutment portion 2222 is flush with the outer circumferential surface of the second cover body 222, and the outer circumferential surface of the second abutment portion 2222 is a surface that abuts against the inner circumferential surface of the first abutment portion 2212 together with the outer circumferential surface of the second cover body 222, and the second surface 2221 of the second cover body 222 and the inner circumferential surface of the second abutment portion 2222 jointly define a groove that can accommodate other components.

[0168] It should be noted that the second cover 222 and the second abutting portion 2222 can be an integrally formed structure, that is, the second cover 222 and the second abutting portion 2222 are an integral structure, and the second cover 222 and the second abutting portion 2222 can be made by an integral forming process such as stamping, casting, bending, or milling. Of course, the second cover 222 and the second abutting portion 2222 can also be a separate structure, that is, the second cover 222 and the second abutting portion 2222 are a separate structure, and the second abutting portion 2222 can be connected to the second surface 2221 of the second cover 222 by welding, bolting, or bonding.

[0169] In this embodiment, a second abutment portion 2222 of an annular structure is protruded from the second surface 2221 of the second cover body 222, and the outer peripheral surface of the second abutment portion 2222 abuts against the inner peripheral surface of the first abutment portion 2212, so that the contact area between the second cover body 222 and the inner peripheral surface of the first abutment portion 2212 can be increased by the second abutment portion 2222 without increasing the thickness of the first cover body 221 and the second cover body 222 stacked on each other, which is beneficial to further enhance the supporting effect of the second cover body 222 on the first abutment portion 2212, and further enhance the structural stability of the outer peripheral surface of the first abutment portion 2212 abutting against the inner peripheral surface of the shell 21, so as to further alleviate the deformation of the first abutment portion 2212.

[0170] According to some embodiments of the present application, as shown in Figure 9, along the first direction X, the first abutment portion 2212 has a first end surface 2212a away from the first surface 2211, and the second abutment portion 2222 has a second end surface 2222a away from the second surface 2221, and the second end surface 2222a is flush with the first end surface 2212a.

[0171] Among them, the second end face 2222a is flush with the first end face 2212a, that is, the end of the first abutting portion 2212 away from the first surface 2211 in the first direction X and the end of the second abutting portion 2222 away from the second surface 2221 in the first direction X are flush with each other, that is, the first end face 2212a and the second end face 2222a are coplanar structures.

[0172] In this embodiment, by setting the first end face 2212a of the first abutting portion 2212 away from the first surface 2211 to a structure that is flush with the second end face 2222a of the second abutting portion 2222 away from the second surface 2221, on the one hand, the contact area between the first abutting portion 2212 and the second abutting portion 2222 can be further increased to enhance the supporting effect of the second cover body 222 on the first abutting portion 2212; on the other hand, the phenomenon of space waste in the battery cell 20 caused by the second abutting portion 2222 protruding from the first end face 2212a can be effectively alleviated.

[0173] In some embodiments, as shown in Figures 6 and 9, the second cover 222 and the second abutting portion 2222 are integrally formed. In other words, the second cover 222 and the second abutting portion 2222 are an integral structure, and the second cover 222 and the second abutting portion 2222 can be made by an integral forming process such as stamping, casting, bending or milling. It should be noted that when the second cover 222 and the second abutting portion 2222 are formed by a bending process, the outer edge of the plate of the plate-like structure is bent to one side along its thickness direction, so that the bent portion forms the second abutting portion 2222, and the unbent portion forms the second cover 222.

[0174] In this embodiment, by setting the second cover body 222 and the second abutment portion 2222 as an integrally formed structure, it is beneficial to improve the structural strength and structural stability between the second cover body 222 and the second abutment portion 2222, so as to reduce the risk of separation between the second abutment portion 2222 and the second cover body 222.

[0175] In some embodiments, please continue to refer to FIG. 6 and FIG. 9 , the inner circumferential surface of the first abutting portion 2212 is parallel to the first direction X.

[0176] In this embodiment, by setting the inner circumferential surface of the first abutment portion 2212 to a structure parallel to the first direction X, it is convenient to assemble the second cover body 222 to the inner side of the first abutment portion 2212 along the first direction X, and it is convenient for the outer circumferential surface of the first cover body 221 and the inner circumferential surface of the first abutment portion 2212 to abut against each other, which is beneficial to reduce the assembly difficulty between the second cover body 222 and the first cover body 221, and thus can improve the production efficiency of the battery cell 20.

[0177] According to some embodiments of the present application, as shown in Figures 7 and 10 , the outer circumferential surface of the first cover 221 abuts against the inner circumferential surface of the housing 21. In other words, the outer circumferential side of the first cover 221 abuts against the inner surface of the housing 21 facing the accommodating cavity 211, so that the first cover 221 is embedded in the housing 21.

[0178] In this embodiment, by abutting the outer peripheral surface of the first cover body 221 against the inner peripheral surface of the shell 21, the outer peripheral surfaces of the first cover body 221 and the first abutting portion 2212 are both structures abutting against the inner peripheral surface of the shell 21, thereby further improving the stability and reliability of the mutual assembly connection between the first cover body 221 and the shell 21.

[0179] According to some embodiments of the present application, please continue to refer to Figures 7 and 10, the outer peripheral surface of the first cover body 221 is flush with the outer peripheral surface of the first abutment portion 2212, and the outer peripheral surface of the first cover body 221 and the outer peripheral surface of the first abutment portion 2212 jointly form a welding surface 2213, and the welding surface 2213 is welded to the inner peripheral surface of the shell 21.

[0180] Among them, the outer peripheral surface of the first cover body 221 is flush with the outer peripheral surface of the first abutment part 2212, that is, the outer peripheral surface of the first cover body 221 and the outer peripheral surface of the first abutment part 2212 are coplanar structures, so that the outer peripheral surface of the first cover body 221 and the outer peripheral surface of the first abutment part 2212 jointly form a welding surface 2213.

[0181] The welding surface 2213 is welded to the inner circumference of the shell 21, that is, the outer circumference of the first cover body 221 and the outer circumference of the first abutting portion 2212 are both used to be welded to the inner circumference of the shell 21, so that the first cover body 221 is connected to the shell 21 and closes the opening 212.

[0182] In this embodiment, by setting the outer circumferential surface of the first cover body 221 and the outer circumferential surface of the first abutment portion 2212 to be flush with each other and jointly defining a welding surface 2213 that is welded to the inner circumferential surface of the shell 21, the end cover 22 is a structure in which the first cover body 221 and the first abutment portion 2212 surrounding the outer side of the second cover body 222 are both welded to the shell 21, thereby effectively increasing the welding surface 2213 between the end cover 22 and the shell 21. After the thickness of the first cover body 221 of the end cover 22 is reduced, there is still enough area to be welded to the shell 21. Under the condition of equal strength of the end cover 22, the area size of the area where the first cover body 221 of the end cover 22 is connected to the shell 21 can be met, and the thickness of the first cover body 221 and the second cover body 222 of the end cover 22 stacked together in the first direction X can be optimized. Therefore, while meeting the structural strength of the end cover 22, the reliability of the connection interface between the end cover 22 and the shell 21 can be improved, and the space utilization rate of the battery cell 20 can be effectively improved.

[0183] According to some embodiments of the present application, referring to Figures 11, 12, and 13, Figure 11 is a cross-sectional view of an end cap 22 of a battery cell 20 provided in still further embodiments of the present application, Figure 12 is a partial enlarged view of a portion C of the end cap 22 shown in Figure 11, and Figure 13 is a partial cross-sectional view of a battery cell 20 provided in still further embodiments of the present application. Along the first direction X, the housing 21 has a third end surface 213 formed at one end thereof where the opening 212 is provided. The third end surface 213 is connected to the inner circumferential surface of the housing 21. Along the first direction X, the third end surface 213 faces the first surface 2211 and is connected to the first surface 2211.

[0184] Among them, a third end face 213 is formed at one end of the shell 21 where the opening 212 is provided, and the third end face 213 is connected to the inner circumferential surface of the shell 21. That is, the third end face 213 is the surface of the end of the shell 21 where the opening 212 is provided, that is, the opening 212 is provided on the third end face 213 of the shell 21, so that the cavity wall surface of the accommodating cavity 211 connected to the opening 212 and the third end face 213 are interconnected structures, that is, the third end face 213 is connected to the inner circumferential surface of the shell 21.

[0185] The third end surface 213 is disposed facing the first surface 2211, and the third end surface 213 is connected to the first surface 2211, that is, the third end surface 213 and the first surface 2211 are disposed opposite each other in the first direction X, and the third end surface 213 is connected to the first surface 2211. In other words, the first cover 221 has a portion protruding from the outer circumferential surface of the first abutting portion 2212, so that the outer circumferential surface of the first cover 221 and the outer circumferential surface of the first abutting portion 2212 are connected to each other through the first surface 2211, so that the outer circumferential surface of the first cover 221, the first surface 2211, and the outer circumferential surface of the first abutting portion 2212 together form a stepped structure.

[0186] Optionally, the connection structure between the third end surface 213 and the first surface 2211 can be various, such as welding connection or bonding.

[0187] In this embodiment, by arranging the third end face 213 of the shell 21 and the first surface 2211 of the first cover body 221 facing each other and connected, the outer edge of the first cover body 221 is a structure that protrudes from the outer peripheral surface of the first abutting portion 2212, so that the end cover 22 can not only abut against the inner peripheral surface of the shell 21 through the first abutting portion 2212, but also be connected to the third end face 213 of the shell 21 through the first surface 2211 of the first cover body 221, thereby enabling the end cover 22 to contact the shell 21 from multiple different directions, which is beneficial to further improve the assembly reliability and structural stability between the end cover 22 and the shell 21.

[0188] In some embodiments, the third end surface 213 is welded to the first surface 2211 .

[0189] In this embodiment, by welding the third end face 213 of the shell 21 and the first surface 2211 of the first cover body 221 to each other, the outer edge of the first cover body 221 protruding from the outer peripheral surface of the first abutment portion 2212 is a structure welded to the shell 21, which is beneficial to improving the connection strength between the first cover body 221 and the shell 21.

[0190] According to some embodiments of the present application, as shown in Figures 6, 9 and 12, the first cover body 221 and the first abutting portion 2212 are integrally formed. In other words, the first cover body 221 and the first abutting portion 2212 are an integral structure, and the first cover body 221 and the first abutting portion 2212 can be made by an integral forming process such as stamping, casting, bending or milling. It should be noted that when the first cover body 221 and the first abutting portion 2212 are formed by a bending process, the outer edge of the plate of the plate-like structure is bent to one side along its thickness direction, so that the bent portion forms the first abutting portion 2212, and the unbent portion is the first cover body 221.

[0191] In this embodiment, by setting the first cover body 221 and the first abutment portion 2212 as an integrally formed structure, on the one hand, the structural strength and structural stability between the first cover body 221 and the first abutment portion 2212 can be effectively improved, so as to reduce the risk of mutual separation between the first abutment portion 2212 and the first cover body 221; on the other hand, it is convenient to set the first cover body 221 and the first abutment portion 2212 as a structure of the same material, thereby facilitating the welding connection between the first cover body 221 and the first abutment portion 2212 and the shell 21.

[0192] According to some embodiments of the present application, as shown in Figures 7, 10, and 13, along the first direction X, the second cover 222 is located on the side of the first cover 221 facing the accommodating cavity 211. In other words, the first surface 2211 of the first cover 221 is disposed facing the accommodating cavity 211 and the electrode assembly 23, that is, in the first direction X, the second cover 222 is closer to the electrode assembly 23 than the first cover 221.

[0193] In this embodiment, by setting the second cover body 222 to be located on the side of the first cover body 221 facing the accommodating cavity 211, the second cover body 222 is a structure located on the inner side of the first cover body 221, so that the second cover body 222 is thinned after the first cover body 221 is connected to the shell 21. This can save the space occupied by the end cover 22 inside the battery cell 20, which is beneficial to improving the internal space utilization of the battery cell 20.

[0194] According to some embodiments of the present application, referring to Figures 14, 15, and 16, Figure 14 is a cross-sectional view of the end cap 22 of a battery cell 20 provided in other embodiments of the present application, Figure 15 is a partial enlarged view of a portion D of the end cap 22 shown in Figure 14, and Figure 16 is a partial cross-sectional view of a battery cell 20 provided in other embodiments of the present application. Along the first direction X, the second cover 222 is located on the side of the first cover 221 facing away from the accommodating cavity 211. In other words, the first surface 2211 of the first cover 221 is disposed away from the accommodating cavity 211 and the electrode assembly 23, i.e., along the first direction X, the second cover 222 is further away from the electrode assembly 23 than the first cover 221.

[0195] In this embodiment, by setting the second cover body 222 to be located on the side of the first cover body 221 away from the accommodating cavity 211, the second cover body 222 is a structure located on the outside of the first cover body 221, thereby facilitating the assembly of the second cover body 222 onto the first cover body 221, and after the first cover body 221 is connected to the shell 21, the interference effect of the second cover body 222 on other components inside the battery cell 20 can be reduced.

[0196] According to some embodiments of the present application, the first cover 221 is connected to the housing 21 by welding.

[0197] In this embodiment, by setting the first cover body 221 and the shell 21 as a structure welded to each other, it is beneficial to improve the connection strength between the first cover body 221 and the shell 21, thereby effectively improving the structural stability and reliability of the end cover 22 assembled to the shell 21.

[0198] In some embodiments, the material of the first cover 221 is the same as that of the housing 21 .

[0199] Exemplarily, the first cover 221 and the housing 21 are both made of aluminum or aluminum alloy. Correspondingly, the first abutting portion 2212 is made of the same material as the first cover 221 , and the second abutting portion 2222 is made of the same material as the second cover 222 .

[0200] It should be noted that the material of the first cover body 221 is the same as that of the shell 21, which means that the main component of the first cover body 221 is the same as that of the shell 21. For example, if the first cover body 221 and the shell 21 are both made of a single material, such as aluminum, then the first cover body 221 and the shell 21 are composed of the same metal elements; if the first cover body 221 and the shell 21 are made of an alloy material or a mixed material, such as aluminum alloy, then the material of the first cover body 221 and the shell 21 is the same, which means that the main components of the first cover body 221 and the shell 21 are the same. If the first cover body 221 and the shell 21 are different only in the content of the components, they are also made of the same material.

[0201] In this embodiment, by setting the material of the first cover body 221 to be the same as the material of the shell 21, it is possible to achieve a structure in which the first cover body 221 and the shell 21 are welded with the same material. On the one hand, it can reduce the difficulty of welding between the first cover body 221 and the shell 21. On the other hand, it can reduce the occurrence of cold welding or welding failure between the first cover body 221 and the shell 21, which is beneficial to improving the welding quality between the first cover body 221 and the shell 21.

[0202] In some embodiments, the first cover 221 is made of aluminum or aluminum alloy, and the second cover 222 is made of steel.

[0203] For example, the second cover 222 may be made of SUS303 steel, SUS316 steel, or SPCC steel.

[0204] In this embodiment, by setting the material of the first cover body 221 to aluminum or aluminum alloy and correspondingly setting the material of the second cover body 222 to steel, on the one hand, the manufacturing cost of the end cover 22 can be reduced, and on the other hand, the strength of the second cover body 222 is much higher than that of the first cover body 221. Therefore, under the end cover 22 of the same structural strength, the thickness of the first cover body 221 and the second cover body 222 stacked together along the first direction X can be further optimized, which is beneficial to further improve the space utilization of the battery cell 20.

[0205] In some embodiments, the first cover 221 and the second cover 222 are compositely connected.

[0206] The first cover 221 and the second cover 222 can be connected to each other in various ways. For example, the first cover 221 and the second cover 222 can be connected by a composite process such as hot pressing or cold pressing. Of course, in other embodiments, the first cover 221 and the second cover 222 can also be connected by bonding, bolting, or welding.

[0207] In this embodiment, the first cover 221 and the second cover 222 are connected by a composite connection structure, which can effectively improve the structural strength and connection stability of the first cover 221 and the second cover 222, and is conducive to reducing the risk of separation between the first cover 221 and the second cover 222.

[0208] 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.

[0209] As shown in FIG. 2 , the battery 100 may further include a box body 10 , in which the battery cells 20 are accommodated.

[0210] 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 .

[0211] 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.

[0212] 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.

[0213] 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.

[0214] 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 .

[0215] 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.

[0216] 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.

[0217] The electrical device may be any of the aforementioned devices or systems using the battery cell 20 .

[0218] According to some embodiments of the present application, as shown in Figures 3 to 10, a battery cell 20 is provided. The battery cell 20 includes a housing 21, an end cap 22, and an electrode assembly 23. The housing 21 has a housing cavity 211 formed therein. The housing cavity 211 has an opening 212 formed at at least one end thereof in a first direction X. The electrode assembly 23 is accommodated within the housing cavity 211. The end cap 22 is connected to the opening 212 of the housing 21 and closes the opening 212. The end cap 22 includes a first cover 221 and a second cover 222 stacked and compositely connected along the first direction X. The second cover 222 is disposed on the side of the first cover 221 facing the housing cavity 211. The second cover 222 has a greater strength than the first cover 221. The strength of the first cover 221 is T1, and the strength of the second cover 222 is T2, satisfying the condition T2-T1≥150 MPa. Along the first direction X, the first cover body 221 has a first surface 2211 facing the second cover body 222, and the first surface 2211 is protruding with a first abutment portion 2212. The first abutment portion 2212 and the first cover body 221 are integrally formed. The material of the first cover body 221, the material of the first abutment portion 2212 and the material of the shell 21 are all the same. The first abutment portion 2212 surrounds the outside of the second cover body 222. The outer peripheral surface of the first cover body 221 is flush with the outer peripheral surface of the first abutment portion 2212. The outer peripheral surface of the first cover body 221 and the outer peripheral surface of the first abutment portion 2212 jointly form a welding surface 2213, and the welding surface 2213 is welded to the inner peripheral surface of the shell 21 so that the end cover 22 closes the opening 212 through the first cover body 221. The outer circumferential surface of the second cover 222 abuts the inner circumferential surface of the first abutting portion 2212. Along the first direction X, the second cover 222 has a second surface 2221 facing away from the first cover 221. A second abutting portion 2222 is protruding from the second surface 2221. The second abutting portion 2222 is an annular structure extending along the circumference of the first abutting portion 2212. The outer circumferential surface of the second abutting portion 2222 abuts the inner circumferential surface of the first abutting portion 2212, and the inner circumferential surface of the first abutting portion 2212 is parallel to the first direction X. Along the first direction X, the first abutting portion 2212 has a first end surface 2212a facing away from the first surface 2211. The second abutting portion 2222 has a second end surface 2222a facing away from the second surface 2221, and the second end surface 2222a is flush with the first end surface 2212a. The first cover 221 is made of aluminum or an aluminum alloy, and the second cover 222 is made of steel.

[0219] 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.

[0220] 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, characterized in that, Comprising: A housing, an accommodation cavity is formed inside, at least one end of the accommodation cavity in the first direction is formed with an opening, and the accommodation cavity is used to accommodate an electrode assembly; And An end cap for closing the opening; Wherein, the end cap includes a first cover body and a second cover body stacked along the first direction, the first cover body is connected to the housing to close the opening, and the strength of the second cover body is greater than that of the first cover body.

2. The battery cell according to claim 1, wherein The strength of the first cover body is T1, and the strength of the second cover body is T2, satisfying T2 - T1 ≥ 150 MPa.

3. The battery cell according to claim 1 or 2, characterized in that, Along the first direction, the first cover body has a first surface facing the second cover body, and a first abutting portion is convexly provided on the first surface, the first abutting portion surrounds the outside of the second cover body, and the outer peripheral surface of the first abutting portion abuts against the inner peripheral surface of the housing.

4. The battery cell according to claim 3, wherein The outer peripheral surface of the second cover body abuts against the inner peripheral surface of the first abutting portion.

5. The battery cell according to claim 4, wherein, Along the first direction, the second cover body has a second surface facing away from the first cover body, and a second abutting portion is convexly provided on the second surface, the second abutting portion is an annular structure extending along the circumferential direction of the first abutting portion, and the outer peripheral surface of the second abutting portion abuts against the inner peripheral surface of the first abutting portion.

6. The battery cell according to claim 5, wherein Along the first direction, the first abutting portion has a first end face facing away from the first surface, and the second abutting portion has a second end face facing away from the second surface, and the second end face is flush with the first end face.

7. The battery cell according to claim 5 or 6, characterized in that, The second cover body and the second abutting portion are integrally formed.

8. The battery cell according to any one of claims 4-7, characterized in that The inner peripheral surface of the first abutting portion is parallel to the first direction.

9. The battery cell according to any one of claims 3-8, characterized in that, The outer peripheral surface of the first cover body abuts against the inner peripheral surface of the housing.

10. The battery cell according to claim 9, wherein, The outer peripheral surface of the first cover body is flush with the outer peripheral surface of the first abutting portion, and the outer peripheral surfaces of the first cover body and the first abutting portion together form a welding surface, and the welding surface is welded to the inner peripheral surface of the housing.

11. The battery cell according to any one of claims 3-8, characterized in that, Along the first direction, one end of the housing where the opening is provided forms a third end face, and the third end face is connected to the inner peripheral surface of the housing; Wherein, along the first direction, the third end face and the first surface face each other, and the third end face is connected to the first surface.

12. The battery cell according to claim 11, characterized in that, The third end face is welded to the first surface.

13. The battery cell according to any one of claims 3-12, characterized in that, The first cover body and the first abutting portion are integrally formed.

14. The battery cell according to any one of claims 1-13, characterized in that, Along the first direction, the second cover body is located on the side of the first cover body facing the accommodation cavity.

15. The battery cell according to any one of claims 1-13, characterized in that, Along the first direction, the second cover body is located on the side of the first cover body away from the accommodation cavity.

16. The battery cell according to any one of claims 1-15, characterized in that, The first cover body is welded to the housing.

17. The battery cell according to claim 16, characterized in that, The material of the first cover body is the same as that of the housing.

18. The battery cell according to any one of claims 1-17, characterized in that, The material of the first cover body includes aluminum or aluminum alloy, and the material of the second cover body includes steel.

19. The battery cell according to any one of claims 1-18, characterized in that, The first cover body and the second cover body are compound-connected.

20. A battery, characterized in that, Including the battery cell according to any one of claims 1 - 19.

21. An electrical device, characterized in that, Including the battery cell according to any one of claims 1 - 19, and the battery cell is used to provide electric energy.

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