Battery monomer, battery device and electric equipment

Abstract

The utility model provides a battery monomer, a battery device and electric equipment. The battery monomer comprises a shell and an electrode assembly, the shell comprises a side wall and a first wall, and the side wall is arranged around the first wall. The first wall comprises a body part and a connecting part which are connected with each other, the body part is connected with the side wall, and the body part and the connecting part are made of different materials. The electrode assembly is accommodated in the housing, and the electrode assembly has a first tab. The material of the connecting part is the same as that of the first tab, and the connecting part is connected with the first tab in a welding manner. The first wall comprises the body part and the connecting part which are connected with each other, and the connecting part is welded with the first tab, so that the input or output of the electric energy of the battery monomer can be realized through the first wall, the number of electrode terminals and current collecting components is reduced, the occupation of the internal space of the battery monomer is reduced, and the energy density is improved. And the connecting part and the first tab are welded by the same material, so that the phenomenon of welding cracks between the first wall and the first tab can be reduced, and the reliability of the single battery is improved.

Description

Technical Field

[0001] The present application relates to the field of batteries, and more specifically, to a battery cell, a battery device, and an electrical device. Background Art

[0002] Batteries are widely used in new energy applications, such as electric vehicles and new energy vehicles. These have become a new trend in the automotive industry. The development of battery technology requires consideration of multiple design factors, including performance parameters such as battery life, discharge capacity, and charge / discharge rate. Furthermore, the battery's energy density must be considered. However, current batteries have a relatively low energy density. Utility Model Content

[0003] The purpose of the embodiments of the present application is to provide a battery cell, a battery device and an electrical device, which are intended to improve the problem of low energy density of batteries in related technologies.

[0004] In the first aspect, an embodiment of the present application provides a battery cell, which includes a shell and an electrode assembly, the shell including a side wall and a first wall, the side wall being arranged around the first wall; the electrode assembly is accommodated in the shell, and the electrode assembly has a first pole ear; wherein, the first wall includes a main body portion and a connecting portion connected to each other, the main body portion is connected to the side wall, the material of the main body portion is different from the material of the connecting portion, the material of the connecting portion is the same as the material of the first pole ear, and the connecting portion is welded to the first pole ear.

[0005] In the above technical solution, the first wall is configured as a main body portion and a connecting portion that are interconnected. The connecting portion is welded to the first tab, and the main body portion is connected to the side wall to achieve electrical connection between the electrode assembly and the first wall, thereby enabling the input or output of electrical energy from the battery cell through the first wall. On the one hand, the number of electrode terminals and current collecting components can be reduced, reducing costs, reducing the internal space occupied by the battery cell, and improving energy density. On the other hand, after the information collection device is electrically connected to the first wall, it can collect usage information of the battery cell, thereby facilitating the information collection device to connect to the battery cell and perform data collection, which helps to reduce the difficulty of data collection from the battery cell and further reduce manufacturing costs. In addition, by setting the material of the connecting part to be the same as that of the first pole ear, on the one hand, it is convenient to weld the connecting part to the first pole ear, which is beneficial to reduce the difficulty of assembling between the first wall and the first pole ear of the electrode assembly, so as to improve the assembly efficiency of the battery cell. On the other hand, it can realize the mutual welding of the first wall and the first pole ear with the same material, so as to alleviate the phenomenon of different melting points and thermal expansion coefficients caused by welding the first wall and the first pole ear due to different materials, thereby reducing the phenomenon of welding cracks between the first wall and the first pole ear, which is beneficial to reduce the risk of leakage of the battery cell, so as to improve the reliability of the battery cell.

[0006] As an optional technical solution of an embodiment of the present application, the main body has an inner surface facing the electrode assembly, the main body is provided with a accommodating cavity, the accommodating cavity extends to the inner surface, and the connecting portion is at least partially accommodated in the accommodating cavity.

[0007] In the above technical solution, the accommodating cavity is recessed from the inner surface of the main body toward the first wall in the direction away from the electrode assembly. By at least partially accommodating the connecting part in the accommodating cavity, the space occupied by the connecting part in the internal space of the battery cell is further reduced, which is beneficial to improving the energy density of the battery cell.

[0008] As an optional technical solution of an embodiment of the present application, the accommodating cavity is an accommodating groove that is recessed from the inner surface in a direction away from the electrode assembly.

[0009] In the above technical solution, when the accommodating cavity is an accommodating groove provided in the main body, the electrolyte is not easily leaked from the accommodating groove, which is beneficial to reducing the leakage risk of the battery cell and improving the reliability of the battery cell.

[0010] As an optional technical solution of an embodiment of the present application, the main body further includes an outer surface opposite to the inner surface, and the accommodating cavity is a through hole passing through the inner surface and the outer surface.

[0011] In the above technical solution, when the accommodating cavity is a through hole penetrating the inner surface and the outer surface, it is convenient to connect the connecting portion and the first pole ear by penetration welding, which is beneficial to reduce the assembly difficulty between the first wall and the first pole ear of the electrode assembly, thereby improving the assembly efficiency of the battery cell.

[0012] As an optional technical solution of the embodiment of the present application, the connecting portion is completely accommodated in the accommodating cavity.

[0013] In the above technical solution, by making the connecting portion completely accommodated in the accommodating cavity, it is beneficial to reduce the occupation of the internal space of the battery cell by the connecting portion, and is beneficial to improving the energy density of the battery cell.

[0014] As an optional technical solution of the embodiment of the present application, the surface of the connecting portion facing the electrode assembly is flush with the inner surface.

[0015] In the above technical solution, by making the surface of the connecting part facing the electrode assembly flush with the inner surface of the main body, it is possible to reduce the occupation of the internal space of the battery cell by the connecting part, which is beneficial to improving the energy density of the battery cell, and it is also possible to facilitate the welding of the connecting part and the first pole ear, which is beneficial to improving the welding quality of the connecting part and the first pole ear.

[0016] As an optional technical solution of the embodiment of the present application, the outer peripheral surface of the connecting portion is welded to the cavity wall of the accommodating cavity.

[0017] In the above technical solution, when the outer peripheral surface of the connecting portion is welded to the wall of the accommodating cavity, high weld quality can be achieved simply by matching the shape and size of the connecting portion with the shape and size of the accommodating cavity. Matching the shape and size of the connecting portion with the shape and size of the accommodating cavity is relatively simple, so welding the outer peripheral surface of the connecting portion to the wall of the accommodating cavity is beneficial for improving weld quality. In addition, butt welding can be used when welding the outer peripheral surface of the connecting portion to the wall of the accommodating cavity. Butt welding requires less heat, making the connecting portion and the main body less likely to deform during welding, thereby improving weld quality.

[0018] As an optional technical solution of an embodiment of the present application, the connecting portion protrudes from the inner surface along the direction of the first wall pointing to the electrode assembly.

[0019] In the above technical solution, by making the connecting portion partially protrude from the accommodating cavity, it is convenient to weld the portion of the connecting portion protruding from the accommodating cavity to the first electrode tab.

[0020] As an optional technical solution of an embodiment of the present application, the outer peripheral surface of the connecting portion is welded to the inner surface.

[0021] In the above technical solution, the inner surface of the main body is welded to the outer peripheral surface of the connecting part, so that the main body and the connecting part are connected in a fillet welding relationship to achieve a welding connection between the main body and the connecting part. The first wall with such a structure can achieve a greater penetration depth at a lower welding power, which is beneficial to improving the welding effect between the connecting part and the main body, thereby effectively improving the connection stability between the connecting part and the main body.

[0022] As an optional technical solution of an embodiment of the present application, the connecting portion and the tab are welded to form a first weld mark. Along the thickness direction of the first wall, the connecting portion and the tab are stacked. The tab and the connecting portion have an overlapping area, and the first weld mark is located in the overlapping area.

[0023] In the above technical solution, the welding connection portion and the first electrode tab can be penetrated from the side of the first wall away from the electrode assembly, which is conducive to reducing the welding difficulty and improving the welding quality.

[0024] As an optional technical solution of an embodiment of the present application, the first electrode tab is a negative electrode tab.

[0025] In the above technical solution, when the first electrode tab is a negative electrode tab, the first wall can serve as the negative electrode of the battery cell to achieve input or output of electrical energy of the battery cell.

[0026] As an optional technical solution of an embodiment of the present application, the material of the connecting portion includes copper, and the material of the main body includes iron.

[0027] In the above technical solution, the connecting portion and the first tab are made of the same material, namely copper. The main body is made of iron to provide the main body with higher strength, thereby facilitating resistance to external forces and protecting components inside the battery cell.

[0028] As an optional technical solution of an embodiment of the present application, the battery cell includes an electrode terminal, which is insulated and arranged in the shell; the electrode assembly also includes a second pole ear, the polarity of the second pole ear is opposite to that of the first pole ear, and the second pole ear is electrically connected to the electrode terminal.

[0029] In the above technical solution, the first wall can be electrically connected to the first pole tab, the electrode terminal can be electrically connected to the second pole tab, the first wall can serve as the positive or negative electrode of the battery cell, and the electrode terminal can serve as the negative or positive electrode of the battery cell to output the electrical energy of the battery cell.

[0030] As an optional technical solution of an embodiment of the present application, the outer shell includes a shell and an end cover, the shell has an opening; the end cover is connected to the shell and closes the opening; wherein the first wall is the end cover, and the main body is connected to the shell.

[0031] In the above technical solution, when the end cover is the first wall, the connecting portion is welded to the first tab, and the main body is welded to the shell, which is easy to assemble and simple and convenient to manufacture.

[0032] As an optional technical solution of the embodiment of the present application, the main body and the shell are both made of steel.

[0033] In the above technical solution, by constructing the main body and shell of steel, the high strength of steel, on the one hand, makes the shell stronger, thereby helping to resist external forces and protect the internal components of the battery cell. On the other hand, the main body and shell are welded together using the same material to alleviate the differences in melting points and thermal expansion coefficients caused by welding the main body and shell. This can reduce the occurrence of weld cracks between the main body and shell, helping to reduce the risk of battery cell leakage and improve battery cell reliability.

[0034] As an optional technical solution of the embodiment of the present application, the battery cell is a cylindrical battery cell.

[0035] In a second aspect, an embodiment of the present application further provides a battery device, which includes the above-mentioned battery cell.

[0036] In a third aspect, an embodiment of the present application further provides an electric device, which includes the above-mentioned battery cell, and the battery cell is used to provide electric energy for the electric device. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] 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.

[0038] Figure 1 A schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0039] Figure 2 An exploded view of a battery device provided in some embodiments of the present application;

[0040] Figure 3 A schematic structural diagram of a battery cell provided in some embodiments of the present application;

[0041] Figure 4 An exploded view of a battery cell provided in some embodiments of the present application;

[0042] Figure 5 An exploded view of a first wall provided for some embodiments of the present application;

[0043] Figure 6 A partial cross-sectional view of a battery cell provided in some embodiments of the present application;

[0044] Figure 7 A schematic structural diagram of a battery cell provided in some other embodiments of the present application;

[0045] Figure 8 Partial cross-sectional views of battery cells provided in some other embodiments of the present application;

[0046] Figure 9 Partial cross-sectional views of battery cells provided in some further embodiments of the present application.

[0047] Icons: 10-casing; 11-first part; 12-second part; 20-battery cell; 2-outer shell; 21-shell; 211-side wall; 212-bottom wall; 22-end cover; 23-first wall; 231-main body; 2311-inner surface; 2312-accommodation cavity; 232-connecting part; 2321-outer peripheral surface; 24-electrode assembly; 241-main body; 242-first pole ear; 243-second pole ear; 25-first weld stamp; 26-second weld stamp; 100-battery device; 200-controller; 300-motor; 1000-vehicle. DETAILED DESCRIPTION

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] The term "plurality" used in this application refers to two or more (including two).

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.).

[0061] 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 NCM622 ), 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.

[0062] 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.

[0063] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0064] 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.).

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] Among them, the gel electrolyte includes a skeleton network with a polymer as the electrolyte, combined with an ionic liquid-lithium salt.

[0077] Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0078] 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.

[0079] 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.

[0080] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0081] 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.

[0082] In some embodiments, the electrode assembly is a laminate structure.

[0083] 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.

[0084] 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.

[0085] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of stacked folded segments.

[0086] 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.

[0087] 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.

[0088] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0089] 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.

[0090] In some embodiments, a battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel housing, an aluminum housing, a plastic housing (e.g., polypropylene), a composite metal housing (e.g., a copper-aluminum composite housing), or an aluminum-plastic film.

[0091] 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.

[0092] The battery device 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.

[0093] In some embodiments, the battery device may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0094] In some embodiments, the battery device may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are housed in the case.

[0095] 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.

[0096] In some embodiments, the battery device may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0097] Batteries are widely used in new energy applications, such as electric vehicles and new energy vehicles. These have become a new trend in the automotive industry. The development of battery technology requires consideration of multiple design factors, including performance parameters such as battery life, discharge capacity, and charge / discharge rate. Furthermore, the battery's energy density must be considered. However, current batteries have a relatively low energy density.

[0098] In the prior art, current collecting members are typically used to connect electrode terminals and tabs of electrode assemblies to enable the input or output of electrical energy in battery cells. However, both the electrode terminals and the current collecting members occupy the internal space of the battery cells, resulting in a low energy density of the battery cells.

[0099] In view of this, an embodiment of the present application provides a battery cell, comprising a housing and an electrode assembly. The housing comprises a sidewall and a first wall, wherein the sidewall is disposed around the first wall. The first wall comprises a main body portion and a connecting portion, the main body portion being connected to the sidewall, and the main body portion and the connecting portion being made of different materials. The electrode assembly is housed within the housing and has a first tab. The connecting portion is made of the same material as the first tab and is welded to the first tab.

[0100] By configuring the first wall as a main body portion and a connecting portion that are interconnected, with the connecting portion welded to the first tab and the main body portion connected to the side wall, an electrical connection is achieved between the electrode assembly and the first wall, thereby enabling the input or output of electrical energy from the battery cell through the first wall. This can reduce the number of electrode terminals and current collecting components, lowering costs, reducing the internal space occupied by the battery cell, and improving energy density. Furthermore, after being electrically connected to the first wall, information collection equipment can collect usage information from the battery cell, facilitating connection of the information collection equipment to the battery cell and data collection, reducing the difficulty of data collection from the battery cell and further reducing manufacturing costs. In addition, by setting the material of the connecting part to be the same as that of the first pole ear, on the one hand, it is convenient to weld the connecting part to the first pole ear, which is beneficial to reduce the difficulty of assembling between the first wall and the first pole ear of the electrode assembly, so as to improve the assembly efficiency of the battery cell. On the other hand, it can realize the mutual welding of the first wall and the first pole ear with the same material, so as to alleviate the phenomenon of different melting points and thermal expansion coefficients caused by welding the first wall and the first pole ear due to different materials, thereby reducing the phenomenon of welding cracks between the first wall and the first pole ear, which is beneficial to reduce the risk of leakage of the battery cell, so as to improve the reliability of the battery cell.

[0101] The technical solutions described in the embodiments of the present application are applicable to batteries and electrical devices using batteries.

[0102] Electrically powered devices may include vehicles, mobile phones, portable devices, laptop computers, ships, spacecraft, electric toys, and electric tools. Spacecraft include airplanes, rockets, space shuttles, and spacecraft. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. Electric tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical devices.

[0103] For the convenience of description, the following embodiments are described by taking the electric device as a vehicle 1000 as an example.

[0104] Please refer to Figure 1 , Figure 1 A schematic structural diagram of a vehicle 1000 provided for some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery device 100 is provided inside the vehicle 1000. The battery device 100 may be provided at the bottom, head or tail of the vehicle 1000. The battery device 100 may be used to power the vehicle 1000. For example, the battery device 100 may serve as an operating power source for the vehicle 1000. The vehicle 1000 may further include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to power the motor 300, for example, for starting, navigating and operating power requirements of the vehicle 1000 during driving.

[0105] In some embodiments of the present application, the battery device 100 can serve not only as an operating power source for the vehicle 1000 , but also as a driving power source for the vehicle 1000 , replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000 .

[0106] Please refer to Figure 2 , Figure 2This is an exploded view of a battery device 100 provided in some embodiments of the present application. The battery device 100 includes a housing 10 and a battery cell 20, with the battery cell 20 housed within the housing 10. The housing 10 is used to provide a storage space for the battery cell 20 and can have various structures. In some embodiments, the housing 10 can include a first portion 11 and a second portion 12, which overlap each other and together define a storage space for the battery cell 20. The second portion 12 can be a hollow structure with one end open. The first portion 11 can be a plate-like structure, with the first portion 11 overlapping the open side of the second portion 12, so that the first portion 11 and the second portion 12 together define a storage space. The first portion 11 and the second portion 12 can also be hollow structures with one end open, with the open side of the first portion 11 overlapping the open side of the second portion 12. Of course, the housing 10 formed by the first portion 11 and the second portion 12 can have various shapes, such as a cylinder, a rectangular parallelepiped, etc.

[0107] In the battery device 100, there may be multiple battery cells 20, which may be connected in series, in parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 may be directly connected in series, in parallel, or in a hybrid connection, and then the entire battery unit 20 may be housed within the housing 10. Alternatively, the battery device 100 may comprise multiple battery cells 20 connected in series, in parallel, or in a hybrid connection to form a battery module, which is then further connected in series, in parallel, or in a hybrid connection to form a single unit and housed within the housing 10. The battery device 100 may also include other structures, such as a busbar assembly for electrically connecting the multiple battery cells 20.

[0108] Each battery cell 20 may be a secondary battery cell or a primary battery cell; it may also be a lithium-sulfur battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, but is not limited thereto. The battery cell 20 may be cylindrical, flat, rectangular, or in other shapes.

[0109] Please refer to Figure 3 、 Figure 4 、 Figure 5 and Figure 6 , Figure 3 This is a schematic structural diagram of a battery cell 20 provided in some embodiments of the present application. Figure 4 An exploded view of a battery cell 20 provided in some embodiments of the present application. Figure 5 An exploded view of the first wall 23 provided for some embodiments of the present application. Figure 6A partial cross-sectional view of a battery cell 20 provided for some embodiments of the present application. An embodiment of the present application provides a battery cell 20, which includes a shell 2 and an electrode assembly 24. The shell 2 includes a side wall 211 and a first wall 23, and the side wall 211 is arranged around the first wall 23. The first wall 23 includes a main body portion 231 and a connecting portion 232 connected to each other, the main body portion 231 is connected to the side wall 211, and the material of the main body portion 231 is different from the material of the connecting portion 232. The electrode assembly 24 is accommodated in the shell 2, and the electrode assembly 24 has a first pole ear 242. The material of the connecting portion 232 is the same as the material of the first pole ear 242, and the connecting portion 232 is welded to the first pole ear 242.

[0110] The battery cell 20 refers to the smallest unit constituting the battery device 100 .

[0111] The housing 2 includes an end cover 22 and a shell 21 . The shell 21 has an opening. The end cover 22 is connected to the shell 21 and closes the opening.

[0112] The end cap 22 refers to a component that covers the opening of the shell 21 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cap 22 can be adapted to the shape of the shell 21 to match the shell 21. Optionally, the end cap 22 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 22 is not easily deformed when squeezed and collided, so that the battery cell 20 can have a higher structural strength and the safety performance can also be improved. The material of the end cap 22 can also be a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not impose special restrictions on this. In some embodiments, the battery cell 20 also includes an insulating member, which is arranged on the inner side of the end cap 22. The insulating member can be used to isolate the electrical connection part 232 in the shell 21 from the end cap 22 to reduce the risk of short circuit. Exemplarily, the insulating member can be plastic, rubber, etc.

[0113] The housing 21 is a component that cooperates with the end cap 22 to form the internal environment of the battery cell 20. This internal environment can be used to accommodate the electrode assembly 24, electrolyte, and other components. The housing 21 and end cap 22 can be separate components. An opening can be provided in the housing 21, and the end cap 22 is placed over the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 22 and housing 21 can be integrated. Specifically, the end cap 22 and housing 21 can form a common joint surface before other components are inserted into the housing. When the interior of the housing 21 is to be enclosed, the end cap 22 is placed over the housing 21. The housing 21 can be of various shapes and sizes, such as a rectangular parallelepiped, a cylinder, or a hexagonal prism. Specifically, the shape of the housing 21 can be determined based on the specific shape and size of the electrode assembly 24. The housing 21 can be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this embodiment of the present application does not impose any particular limitations on this.

[0114] The electrode assembly 24 is a component in the battery cell 20 where electrochemical reactions occur. One or more electrode assemblies 24 may be contained in the housing 2. The electrode assembly 24 is mainly formed by winding or stacking positive and negative electrode sheets, and a separator is usually provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets containing active materials constitute the main body 241 of the electrode assembly 24, and the portions of the positive and negative electrode sheets without active materials each constitute a tab. The positive tab and the negative tab may be located together at one end of the main body 241 or respectively at both ends of the main body 241. During the charge and discharge process of the battery device 100, the positive electrode active material and the negative electrode active material react with the electrolyte.

[0115] In an embodiment where the housing 21 is open at only one end, the end cap 22 may serve as the first wall 23, with the side wall 211 being part of the housing 21. Alternatively, the bottom wall 212 of the housing 21, which faces the end cap 22, may serve as the first wall 23, with the side wall 211 and the first wall 23 being integrally formed to form the housing 21. In an embodiment where openings are formed at both opposing ends of the housing 21, one of the end caps 22 may serve as the first wall 23, with the side wall 211 serving as the housing 21.

[0116] The sidewall 211 can be cylindrical, making the battery cell 20 a cylindrical battery cell; the sidewall 211 can also be rectangular, making the battery cell 20 a square-shell battery cell or a blade-shaped battery cell. The sidewall 211 and the first wall 23 can be integrally formed, with the sidewall 211 and the first wall 23 forming the housing 21, with the end of the sidewall 211 away from the first wall 23 forming an opening in the housing 21. The sidewall 211 and the first wall 23 can also be separate bodies, with the first wall 23 forming the end cap 22, and the end of the sidewall 211 near the first wall 23 forming an opening in the housing 21. In embodiments where the sidewall 211 and the first wall 23 are separate bodies, the first wall 23 and the sidewall 211 can be connected by welding, bonding, crimping, or other methods.

[0117] The main body 231 is the portion of the first wall 23 that is connected to the side wall 211. The connecting portion 232 is the portion of the first wall 23 that is welded to the first tab 242 to achieve electrical connection with the first tab 242. The main body 231 and the connecting portion 232 are connected, and the connection between the connecting portion 232 and the main body 231 can be achieved in various ways, such as clamping, bolting, laser welding, plating, friction welding, or ultrasonic welding.

[0118] The material of the main body 231 is different from that of the connecting portion 232, that is, the main component of the main body 231 is different from the main component of the connecting portion 232. The main component of the main body 231 is the component that accounts for at least 50% of the main body 231's composition. Similarly, the main component of the connecting portion 232 is the component that accounts for at least 50% of the connecting portion 232's composition. The connecting portion 232 can also be made of a variety of materials, such as copper or aluminum. If the first tab 242 is a positive tab, the first tab 242 is typically made of aluminum. Since the material of the connecting portion 232 is the same as that of the first tab 242, the main component of the connecting portion 232 is aluminum, and its content is at least 50%. If the first tab 242 is a negative tab, the first tab 242 is typically made of copper. Since the material of the connecting portion 232 is the same as that of the first tab 242, the main component of the connecting portion 232 is copper, and its content is at least 50%. In other words, the material of the connection portion 232 being different from the material of the main body 231 means that the main component of the connection portion 232 is different from the main component of the main body 231. For example, if the connection portion 232 and the main body 231 are both made of a single material, such as copper or aluminum, then the materials of the connection portion 232 and the main body 231 are composed of different metal elements. If the connection portion 232 and the main body 231 are made of an alloy or a mixed material, such as an aluminum alloy or steel, then the material difference between the connection portion 232 and the main body 231 means that the main components of the connection portion 232 and the main body 231 are different, that is, the components in the alloy or mixed material that have a different content of 50% or more are different. Optionally, the material of the main body 231 can be iron, aluminum, steel, or an aluminum alloy.

[0119] The first tab 242 can be a positive tab or a negative tab. When the first tab 242 is a positive tab, the first wall 23 can serve as the positive electrode of the battery cell 20. When the first tab 242 is a negative tab, the first wall 23 can serve as the negative electrode of the battery cell 20.

[0120] The material of the first pole tab 242 is the same as that of the connecting portion 232, that is, the main component of the first pole tab 242 is the same as the main component of the connecting portion 232. The main component of the first pole tab 242 is the component that accounts for more than 50% of the components of the first pole tab 242. Similarly, the main component of the connecting portion 232 is the component that accounts for more than 50% of the components of the connecting portion 232. The first pole tab 242 can also be made of a variety of materials, such as copper or aluminum. If the first pole tab 242 is a positive pole tab, the material of the first pole tab 242 is usually aluminum, and the main component of the connecting portion 232 is also aluminum, with a content of more than 50%. If the first pole tab 242 is a negative pole tab, the material of the first pole tab 242 is usually copper, and the main component of the connecting portion 232 is also copper, with a content of more than 50%. That is to say, the material of the connecting portion 232 is the same as the material of the first pole tab 242, which means that the main component of the connecting portion 232 is the same as the main component of the first pole tab 242. For example, if the connecting portion 232 and the first pole tab 242 are both made of a single material, such as copper or aluminum, the material of the connecting portion 232 and the first pole tab 242 is composed of the same metal element; if the connecting portion 232 and the first pole tab 242 are made of an alloy material or a mixed material, such as an aluminum alloy or steel, the material of the connecting portion 232 and the first pole tab 242 is different, which means that the main components of the connecting portion 232 and the first pole tab 242 are different, that is, the components with a content of more than 50% in the alloy material or the mixed material are different.

[0121] By configuring the first wall 23 as a main body portion 231 and a connecting portion 232 that are interconnected, with the connecting portion 232 welded to the first electrode tab 242 and the main body portion 231 connected to the side wall 211, an electrical connection is established between the electrode assembly 24 and the first wall 23, thereby enabling the input or output of electrical energy from the battery cell 20 through the first wall 23. This can, on the one hand, reduce the number of electrode terminals and current collecting components required, lowering costs, reducing the internal space occupied by the battery cell 20, and improving energy density. On the other hand, once the information collection device is electrically connected to the first wall 23, it can collect usage information from the battery cell 20, thereby facilitating the information collection device's connection to the battery cell 20 and data collection. This reduces the difficulty of data collection from the battery cell 20 and further reduces manufacturing costs. In addition, by setting the material of the connecting portion 232 to be the same as that of the first pole ear 242, on the one hand, it is convenient to weld the connecting portion 232 to the first pole ear 242, which is beneficial to reduce the difficulty of assembling the first wall 23 and the first pole ear 242 of the electrode assembly 24, thereby improving the assembly efficiency of the battery cell 20. On the other hand, it can achieve mutual welding of the first wall 23 and the first pole ear 242 with the same material, thereby alleviating the phenomenon of different melting points and thermal expansion coefficients caused by welding the first wall 23 and the first pole ear 242 due to different materials, thereby reducing the phenomenon of welding cracks between the first wall 23 and the first pole ear 242, which is beneficial to reduce the risk of leakage of the battery cell 20, thereby improving the reliability of the battery cell 20.

[0122] Please refer to Figure 3 、 Figure 4 、 Figure 5 and Figure 6 In some embodiments, the body portion 231 has an inner surface 2311 facing the electrode assembly 24 . The body portion 231 is provided with a receiving cavity 2312 . The receiving cavity 2312 extends to the inner surface 2311 . The connecting portion 232 is at least partially received in the receiving cavity 2312 .

[0123] The inner surface 2311 refers to the surface of the body portion 231 facing the electrode assembly 24. The accommodating cavity 2312 is recessed from the inner surface 2311 of the body portion 231 toward the first wall 23 away from the electrode assembly 24. In some embodiments, the accommodating cavity 2312 is a accommodating groove provided on the inner surface 2311. In other embodiments, the accommodating cavity 2312 is a through hole that passes through the body portion 231 along the thickness direction of the first wall 23. Please refer to Figure 3 、 Figure 4 、 Figure 5 and Figure 6 The thickness direction of the first wall 23 is the X direction shown in the figure.

[0124] The connecting portion 232 may be partially accommodated in the accommodating cavity 2312 and partially protrude from the accommodating cavity 2312 , or the connecting portion 232 may be completely accommodated in the accommodating cavity 2312 .

[0125] The accommodating cavity 2312 is recessed from the inner surface 2311 of the main body 231 toward the first wall 23 away from the electrode assembly 24. By at least partially accommodating the connecting portion 232 in the accommodating cavity 2312, the space occupied by the connecting portion 232 in the internal space of the battery cell 20 is further reduced, which is beneficial to improving the energy density of the battery cell 20.

[0126] Please refer to Figure 3 、 Figure 4 、 Figure 5 and Figure 6 In some embodiments, the accommodating cavity 2312 is an accommodating groove that is recessed from the inner surface 2311 in a direction away from the electrode assembly 24 .

[0127] The receiving groove can be formed by various methods, such as stamping, cold heading, etc. Taking stamping as an example, the receiving groove can be stamped on the inner surface 2311 of the main body 231 along the direction of the electrode assembly 24 pointing to the first wall 23.

[0128] When the accommodating cavity 2312 is a accommodating groove disposed in the main body 231 , the electrolyte is less likely to leak from the accommodating groove, which helps to reduce the leakage risk of the battery cell 20 and improve the reliability of the battery cell 20 .

[0129] Please refer to Figure 4 、 Figure 5 、 Figure 7 and Figure 8 In other embodiments, the main body 231 further includes an outer surface opposite to the inner surface 2311 , and the accommodating cavity 2312 is a through hole that penetrates the inner surface 2311 and the outer surface.

[0130] The outer surface is the surface of the body portion 231 facing away from the electrode assembly 24. Along the thickness direction of the first wall 23, the inner surface 2311 and the outer surface are arranged opposite to each other.

[0131] The accommodating cavity 2312 is a through hole, and the accommodating cavity 2312 passes through the inner surface 2311 of the main body 231 and the outer surface of the main body 231 along the thickness direction of the first wall 23 .

[0132] When the accommodating cavity 2312 is a through hole that passes through the inner surface 2311 and the outer surface, it is convenient to connect the connecting portion 232 and the first pole ear 242 by penetration welding, which is beneficial to reduce the assembly difficulty between the first wall 23 and the first pole ear 242 of the electrode assembly 24, thereby improving the assembly efficiency of the battery cell 20.

[0133] Please refer to Figure 4 、 Figure 5 、 Figure 7 and Figure 8 In some embodiments, the connecting portion 232 is completely accommodated in the accommodating cavity 2312 .

[0134] By completely accommodating the connecting portion 232 in the accommodating cavity 2312 , the internal space occupied by the connecting portion 232 in the battery cell 20 is reduced, which helps to improve the energy density of the battery cell 20 .

[0135] Please refer to Figure 4 、 Figure 5 、 Figure 7 and Figure 8 In some embodiments, the surface of the connecting portion 232 facing the electrode assembly 24 is flush with the inner surface 2311 .

[0136] The surface of the connecting portion 232 facing the electrode assembly 24 is also the surface of the connecting portion 232 that is closest to the electrode assembly 24 along the thickness direction of the first wall 23. The surface of the connecting portion 232 facing the electrode assembly 24 is flush with the inner surface 2311, which can also be understood as the surface of the connecting portion 232 facing the electrode assembly 24 and the inner surface 2311 of the main body 231 are located in the same plane.

[0137] By making the surface of the connecting portion 232 facing the electrode assembly 24 flush with the inner surface 2311 of the main body 231, the occupation of the internal space of the battery cell 20 by the connecting portion 232 can be reduced, which is beneficial to improving the energy density of the battery cell 20, and the welding of the connecting portion 232 and the first pole ear 242 can be facilitated, which is beneficial to improving the welding quality of the connecting portion 232 and the first pole ear 242.

[0138] Please refer to Figure 4 、 Figure 5 、 Figure 7 and Figure 8 In some embodiments, the outer peripheral surface 2321 of the connecting portion 232 is welded to the cavity wall of the accommodating cavity 2312 .

[0139] When the accommodating cavity 2312 is a accommodating groove, the cavity wall surface of the accommodating cavity 2312 is the groove side surface of the accommodating groove. When the accommodating cavity 2312 is a through hole, the cavity wall surface of the accommodating cavity 2312 is the hole wall surface of the through hole.

[0140] Please refer to Figure 8 ,exist Figure 8 In the embodiment shown, the outer circumference 2321 of the connecting portion 232 is welded to the wall of the accommodating cavity 2312 to form the second welded portion 26. Optionally, the outer circumference 2321 of the connecting portion 232 is welded to the wall of the accommodating cavity 2312 by butt welding.

[0141] When welding the outer circumferential surface 2321 of the connecting portion 232 to the wall of the accommodating cavity 2312, high welding quality can be achieved by simply matching the shape and size of the connecting portion 232 with the shape and size of the accommodating cavity 2312. Matching the shape and size of the connecting portion 232 with the shape and size of the accommodating cavity 2312 is relatively simple. Therefore, welding the outer circumferential surface 2321 of the connecting portion 232 to the wall of the accommodating cavity 2312 is beneficial for improving welding quality. In addition, butt welding can be used when welding the outer circumferential surface 2321 of the connecting portion 232 to the wall of the accommodating cavity 2312. Butt welding requires less heat, making the connecting portion 232 and the main body 231 less likely to deform during welding, thereby improving welding quality.

[0142] Please refer to Figure 9 , Figure 9 This is a partial cross-sectional view of a battery cell 20 provided in some other embodiments of the present application. In some other embodiments, the connecting portion 232 protrudes from the inner surface 2311 along the direction of the first wall 23 pointing toward the electrode assembly 24 .

[0143] Please refer to Figure 9 ,exist Figure 9 In the illustrated embodiment, a portion of the connecting portion 232 is accommodated in the accommodating cavity 2312 , and another portion of the connecting portion 232 is located outside the accommodating cavity 2312 .

[0144] Along the thickness direction of the first wall 23 , the connecting portion 232 has a first surface facing the electrode assembly 24 . When the connecting portion 232 protrudes from the inner surface 2311 along the direction of the first wall 23 pointing to the electrode assembly 24 , the first surface is closer to the electrode assembly 24 than the inner surface 2311 .

[0145] By making the connecting portion 232 partially protrude from the accommodating cavity 2312 , it is convenient to weld the portion of the connecting portion 232 protruding from the accommodating cavity 2312 to the first electrode tab 242 .

[0146] Please refer to Figure 9 In some other embodiments, the outer peripheral surface 2321 of the connecting portion 232 is welded to the inner surface 2311 .

[0147] The main body portion 231 and the connecting portion 232 may be connected by fillet welding, so that the outer peripheral surface 2321 of the connecting portion 232 and the inner surface 2311 of the main body portion 231 are welded.

[0148] By welding the inner surface 2311 of the main body 231 to the outer peripheral surface 2321 of the connecting portion 232, a fillet welding relationship is established between the main body 231 and the connecting portion 232 to achieve a welding connection between the main body 231 and the connecting portion 232. The first wall 23 with such a structure can achieve a greater penetration depth at a lower welding power, which is beneficial to improving the welding effect between the connecting portion 232 and the main body 231, thereby effectively improving the connection stability between the connecting portion 232 and the main body 231.

[0149] Please refer to Figure 9 In some embodiments, the connecting portion 232 is welded to the tab to form a first weld mark 25. Along the thickness direction of the first wall 23, the connecting portion 232 and the tab are stacked, and the tab and the connecting portion 232 have an overlapping region. The first weld mark 25 is located in the overlapping region.

[0150] The first weld mark 25 is a weld mark formed by welding the connecting portion 232 to the tab.

[0151] The connecting portion 232 and the tab are stacked along the thickness direction of the first wall 23, with the tab and the connecting portion 232 forming an overlapping region. The overlapping region refers to the area where the tab and the connecting portion 232 overlap. In some embodiments, the projection of the tab along the thickness direction of the first wall 23 is completely within the connecting portion 232, in which case the entire tab is located in the overlapping region. In other embodiments, the projection of the connecting portion 232 along the thickness direction of the first wall 23 is completely within the tab, in which case the entire connecting portion 232 is located in the overlapping region.

[0152] The first weld mark 25 is located in the overlapping area. In other words, the connecting portion 232 and the tab are welded in the overlapping area. Optionally, the connecting portion 232 and the tab are welded through.

[0153] The welding connection portion 232 and the first electrode tab 242 can be penetrated from the side of the first wall 23 facing away from the electrode assembly 24, which helps to reduce welding difficulty and improve welding quality.

[0154] In some embodiments, the first tab 242 is a negative tab.

[0155] The first electrode tab 242 is a negative electrode tab. The material of the first electrode tab 242 can be copper. The material of the connecting portion 232 can also include copper.

[0156] When the first electrode tab 242 is a negative electrode tab, the first wall 23 can serve as the negative electrode of the battery cell 20 to enable input or output of electrical energy of the battery cell 20 .

[0157] In some embodiments, the connection portion 232 is made of copper, and the body portion 231 is made of iron.

[0158] Optionally, the material of the main body 231 is steel, and the material of the main body 231 can be low carbon steel, medium carbon steel, or high carbon steel.

[0159] The connecting portion 232 and the first tab 242 are made of the same material, copper. The body 231 is made of iron to provide greater strength, thereby resisting external forces and protecting components within the battery cell 20.

[0160] In some embodiments, the electrode terminal is insulated and disposed in the housing 2. The electrode assembly 24 further includes a second electrode tab 243. The second electrode tab 243 has a polarity opposite to that of the first electrode tab 242 and is electrically connected to the electrode terminal.

[0161] The electrode terminal is a component for electrically connecting to the second tab 243 of the electrode assembly 24 to input or output electrical energy of the battery cell 20. The electrode terminal is insulated and mounted on the first wall 23, that is, the electrode terminal is insulated and isolated from the first wall 23.

[0162] The second electrode tab 243 is the aforementioned negative or positive electrode tab. In some embodiments, the second electrode tab 243 is directly connected to the electrode terminal. In other embodiments, the battery cell 20 further includes a current collecting member that connects the second electrode tab 243 to the second electrode terminal to direct electrical energy from the electrode assembly 24 to the electrode terminal or to receive electrical energy from the electrode terminal.

[0163] The polarity of the first electrode tab 242 and the second electrode tab 243 are opposite. For example, when the first electrode tab 242 is a positive electrode tab, the second electrode tab 243 is a negative electrode tab. In this case, the first wall 23 serves as the positive electrode of the battery cell 20, and the electrode terminal serves as the negative electrode of the battery cell 20. When the first electrode tab 242 is a negative electrode tab, the second electrode tab 243 is a positive electrode tab. In this case, the first wall 23 serves as the negative electrode of the battery cell 20, and the electrode terminal serves as the positive electrode of the battery cell 20.

[0164] The first wall 23 can be electrically connected to the first pole tab 242 , and the electrode terminal can be electrically connected to the second pole tab 243 . The first wall 23 can serve as the positive or negative electrode of the battery cell 20 , and the electrode terminal can serve as the negative or positive electrode of the battery cell 20 to output the electrical energy of the battery cell 20 .

[0165] Please refer again Figure 3 and Figure 4 The housing 2 includes a shell and an end cover 22. The shell has an opening. The end cover 22 is connected to the shell and closes the opening. The first wall 23 is the end cover 22, and the main body 231 is connected to the shell.

[0166] In an embodiment where the shell 21 is opened at only one end, the end cover 22 serves as the first wall 23 and the side wall 211 is a part of the shell 21 . In this case, the main body 231 can be welded to the side wall 211 .

[0167] In an embodiment where openings are formed at both opposite ends of the shell 21 , one of the two end covers 22 may serve as the first wall 23 , the side wall 211 is the shell 21 , and the main body 231 may be welded to the shell.

[0168] When the end cover 22 is the first wall 23 , the connecting portion 232 is welded to the first tab 242 , and the main body 231 is welded to the shell, which is convenient for assembly and easy to manufacture.

[0169] In some embodiments, the body portion 231 and the housing are both made of steel.

[0170] For example, the steel material may be carbon steel, alloy steel, stainless steel, or the like.

[0171] In some embodiments, the steel material is carbon steel or stainless steel.

[0172] Illustratively, the carbon steel may be low carbon steel, medium carbon steel, or high carbon steel.

[0173] By constructing the main body 231 and the shell of steel, the high strength of steel improves the strength of the outer shell 2, thereby helping to resist external forces and protect the components within the battery cell 20. Furthermore, the main body 231 and the shell are welded together using the same material to mitigate the differences in melting points and thermal expansion coefficients caused by welding the two materials. This reduces the risk of weld cracks between the main body 231 and the shell, thereby reducing the risk of leakage from the battery cell 20 and improving the reliability of the battery cell 20.

[0174] Please refer to Figure 3 and Figure 4 In some embodiments, the battery cell 20 is a cylindrical battery cell.

[0175] The embodiment of the present application further provides a battery device 100 , which includes the above-mentioned battery cell 20 .

[0176] An embodiment of the present application further provides an electrical device, which includes the above-mentioned battery cell 20, and the battery cell 20 is used to provide electrical energy to the electrical device.

[0177] According to some embodiments of this application, please refer to Figures 3 to 9 .

[0178] An embodiment of the present application provides a battery cell 20, comprising a housing 2 and an electrode assembly 24. The housing 2 comprises a sidewall 211 and a first wall 23, with the sidewall 211 surrounding the first wall 23. The first wall 23 comprises a main body 231 and a connecting portion 232, which are connected to each other. The main body 231 is connected to the sidewall 211, and the material of the main body 231 and the material of the connecting portion 232 are different. The electrode assembly 24 is housed within the housing 2 and has a first tab 242. The connecting portion 232 is made of the same material as the first tab 242, and the connecting portion 232 is welded to the first tab 242. By providing the first wall 23 with the main body 231 and the connecting portion 232 connected to each other, the connecting portion 232 being welded to the first tab 242, and the main body 231 being connected to the sidewall 211, an electrical connection is established between the electrode assembly 24 and the first wall 23, thereby enabling the input or output of electrical energy from the battery cell 20 through the first wall 23. On the one hand, this can reduce the number of electrode terminals and current collecting components required, lowering costs, reducing the internal space occupied by the battery cell 20, and improving energy density. On the other hand, once the information collection device is electrically connected to the first wall 23, it can collect usage information from the battery cell 20. This facilitates connection of the information collection device to the battery cell 20 and data collection, reducing the difficulty of data collection from the battery cell 20 and further reducing manufacturing costs. In addition, by setting the material of the connecting portion 232 to be the same as that of the first pole ear 242, on the one hand, it is convenient to weld the connecting portion 232 to the first pole ear 242, which is beneficial to reduce the difficulty of assembling the first wall 23 and the first pole ear 242 of the electrode assembly 24, thereby improving the assembly efficiency of the battery cell 20. On the other hand, it can achieve mutual welding of the first wall 23 and the first pole ear 242 with the same material, thereby alleviating the phenomenon of different melting points and thermal expansion coefficients caused by welding the first wall 23 and the first pole ear 242 due to different materials, thereby reducing the phenomenon of welding cracks between the first wall 23 and the first pole ear 242, which is beneficial to reduce the risk of leakage of the battery cell 20, thereby improving the reliability of the battery cell 20.

[0179] The main body 231 has an inner surface 2311 facing the electrode assembly 24. The main body 231 is provided with a receiving cavity 2312, which extends to the inner surface 2311. The connecting portion 232 is at least partially received in the receiving cavity 2312. The receiving cavity 2312 is recessed from the inner surface 2311 of the main body 231 toward the first wall 23, away from the electrode assembly 24. By at least partially receiving the connecting portion 232 in the receiving cavity 2312, the internal space occupied by the connecting portion 232 in the battery cell 20 is further reduced, which helps to improve the energy density of the battery cell 20.

[0180] In some embodiments, the surface of the connecting portion 232 facing the electrode assembly 24 is flush with the inner surface 2311, and the outer peripheral surface 2321 of the connecting portion 232 is welded to the cavity wall of the accommodating cavity 2312. When the outer peripheral surface 2321 of the connecting portion 232 is welded to the cavity wall of the accommodating cavity 2312, the welding quality can be improved by simply matching the shape and size of the connecting portion 232 with the shape and size of the accommodating cavity 2312. Matching the shape and size of the connecting portion 232 with the shape and size of the accommodating cavity 2312 is relatively simple. Therefore, welding the outer peripheral surface 2321 of the connecting portion 232 to the cavity wall of the accommodating cavity 2312 helps improve the welding quality. In addition, butt welding can be used when welding the outer peripheral surface 2321 of the connecting portion 232 to the cavity wall of the accommodating cavity 2312. Butt welding requires less heat, making the connecting portion 232 and the main body 231 less likely to deform during welding, thereby improving the welding quality.

[0181] In other embodiments, the connecting portion 232 protrudes from the inner surface 2311 along the direction of the first wall 23 pointing toward the electrode assembly 24, and the outer peripheral surface 2321 of the connecting portion 232 is welded to the inner surface 2311. By welding the inner surface 2311 of the main body 231 and the outer peripheral surface 2321 of the connecting portion 232, a fillet welding relationship is established between the main body 231 and the connecting portion 232, thereby achieving a welded connection between the main body 231 and the connecting portion 232. The first wall 23 with such a structure can achieve a greater penetration at a lower welding power, which is beneficial to improving the welding effect between the connecting portion 232 and the main body 231, thereby effectively improving the connection stability between the connecting portion 232 and the main body 231.

[0182] The connecting portion 232 is made of copper, while the main body 231 is made of iron. The main body 231 and the sidewall 211 are made of the same material. The connecting portion 232 and the first tab 242 are made of the same material, both of which are copper. The iron material of the main body 231 provides greater strength, helping to resist external forces and protect the components within the battery cell 20. By making the main body 231 and the sidewall 211 of the same material, welding the two sides is facilitated.

[0183] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. 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: include: The housing comprises a side wall and a first wall, wherein the side wall is arranged around the first wall; an electrode assembly housed in the housing, the electrode assembly having a first electrode tab; The first wall includes a main body portion and a connecting portion connected to each other, the main body portion is connected to the side wall, the material of the main body portion is different from the material of the connecting portion, the material of the connecting portion is the same as the material of the first electrode tab, and the connecting portion is welded to the first electrode tab.

2. The battery cell according to claim 1, characterized in that: The main body has an inner surface facing the electrode assembly. The main body is provided with an accommodating cavity extending to the inner surface. The connecting portion is at least partially accommodated in the accommodating cavity.

3. The battery cell according to claim 2, characterized in that: The accommodating cavity is an accommodating groove that is recessed from the inner surface in a direction away from the electrode assembly.

4. The battery cell according to claim 2, characterized in that: The main body further includes an outer surface opposite to the inner surface, and the accommodating cavity is a through hole penetrating the inner surface and the outer surface.

5. The battery cell according to claim 2, characterized in that: The connecting portion is completely accommodated in the accommodating cavity.

6. The battery cell according to claim 5, characterized in that: A surface of the connecting portion facing the electrode assembly is flush with the inner surface.

7. The battery cell according to claim 6, characterized in that: The outer peripheral surface of the connecting portion is welded to the cavity wall surface of the accommodating cavity.

8. The battery cell according to claim 2, characterized in that: The connecting portion protrudes from the inner surface along a direction from the first wall to the electrode assembly.

9. The battery cell according to claim 8, characterized in that: The outer peripheral surface of the connecting portion is welded to the inner surface.

10. The battery cell according to any one of claims 1 to 9, characterized in that: The connecting portion and the tab are welded to form a first weld mark. The connecting portion and the tab are stacked along the thickness direction of the first wall. The tab and the connecting portion have an overlapping area, and the first weld mark is located in the overlapping area.

11. The battery cell according to any one of claims 1 to 9, characterized in that: The first electrode tab is a negative electrode tab.

12. The battery cell according to any one of claims 1 to 9, characterized in that: The connecting portion is made of copper, and the main body is made of iron.

13. The battery cell according to any one of claims 1 to 9, characterized in that: The battery cell includes an electrode terminal, and the electrode terminal is insulated and disposed on the housing; The electrode assembly further includes a second electrode tab having a polarity opposite to that of the first electrode tab, and the second electrode tab is electrically connected to the electrode terminal.

14. The battery cell according to any one of claims 1 to 9, characterized in that: The housing comprises: a housing having an opening; an end cover connected to the housing and closing the opening; Wherein, the first wall is the end cover, and the main body is connected to the shell.

15. The battery cell according to claim 14, characterized in that: The main body and the shell are both made of steel.

16. The battery cell according to any one of claims 1 to 9, characterized in that: The battery cell is a cylindrical battery cell.

17. A battery device, characterized in that: The invention comprises a battery cell according to any one of claims 1 to 16.

18. An electrical device, characterized in that: The battery cell comprises a battery cell according to any one of claims 1 to 16, wherein the battery cell is used to provide electrical energy to the electrical device.

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