Battery cell, battery, and electrical apparatus

Abstract

A battery cell (7), a battery (2), and an electrical apparatus. The battery cell (7) comprises a casing (20), an electrode assembly (10), and an electrode terminal (30). The casing (20) comprises a wall portion (23). The electrode assembly (10) is accommodated in the casing (20) and comprises tabs (12). The electrode terminal (30) is arranged on the wall portion (23); the side of the electrode terminal (30) away from the electrode assembly (10) in the thickness direction of the wall portion (23) is provided with an outer surface (31), the electrode terminal (30) is provided with a recessed portion (32) recessed from the outer surface (31), the electrode terminal (30) comprises a connecting portion (33) arranged at the bottom of the recessed portion (32), and the connecting portion (33) is electrically connected to the tabs (12).

Description

Battery cells, batteries, and electrical devices Technical Field

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

[0002] With the advancement of battery technology, battery cells are being used in a growing number of fields and are gradually replacing traditional fossil fuels in the automotive powertrain sector. Battery cells store chemical energy and controllably convert it into electrical energy. In recyclable battery cells, after discharge, the active material can be activated by recharging for continued use.

[0003] How to improve the reliability of battery cells is an important research direction in the industry.

[0004] Summary of the Invention

[0005] The present application provides a battery cell, a battery, and an electrical device, which can improve reliability.

[0006] In a first aspect, the present application provides a battery cell comprising a housing, an electrode assembly, and an electrode terminal. The housing comprises a wall portion. The electrode assembly is housed within the housing and includes a tab. The electrode terminal is disposed on the wall portion, and has an outer surface on a side of the wall portion facing away from the electrode assembly along the thickness direction of the wall portion. The electrode terminal is provided with a recessed portion recessed from the outer surface, and includes a connecting portion disposed at the bottom of the recessed portion, the connecting portion being electrically connected to the tab.

[0007] By providing a recess, the dimension of the connection part in the thickness direction can be reduced, making it easier to connect the connection part with the components inside the shell from the outside of the connection part, reducing the risk of particles remaining on the connection part entering the shell, and improving reliability.

[0008] In some embodiments, the outer surface of the electrode terminal is configured to contact and connect with a battery's current busbar. This allows at least a portion of the current to flow directly between the electrode terminal and the current busbar, bypassing other components. This shortens the conductive path between the electrode terminal and the current busbar, reduces resistance, and improves the battery's current handling capacity.

[0009] In some embodiments, the electrode terminal is used to weld to the busbar component and form a first weld portion, and the projection of the first weld portion and the recess in the thickness direction of the wall portion does not overlap. The first weld portion formed by welding can reduce the resistance between the electrode terminal and the busbar component, improve the flow capacity, and increase the connection strength between the electrode terminal and the busbar component. During the welding process, the electrode terminal can limit the molten liquid formed after the busbar component melts, reduce the risk of the molten liquid flowing into the recess, reduce the possibility of the busbar component being welded through and forming a through hole, improve the flow capacity of the first weld portion, and improve the reliability of the battery cell.

[0010] In some embodiments, the wall portion is provided with an electrode lead-out hole, which extends through the wall portion in the thickness direction. The electrode terminal further comprises a terminal body and a first retaining portion. The outer surface of the electrode terminal comprises a first outer surface of the terminal body and a second outer surface of the first retaining portion. The recessed portion is recessed from the first outer surface toward the electrode assembly. The terminal body is at least partially accommodated in the electrode lead-out hole. The first retaining portion is located on a side of the wall portion facing away from the electrode assembly and is connected to the outer peripheral surface of the terminal body. The connecting portion is connected to the terminal body.

[0011] By arranging the terminal body to extend into the electrode lead-out hole, it is possible to facilitate connection between the connecting portion and other components inside the housing. The wall portion can block the first limiting portion, thereby reducing the risk of the electrode terminal falling into the housing through the electrode lead-out hole.

[0012] In some embodiments, along the thickness direction of the wall portion, the size of the terminal body is larger than the size of the first limiting portion, and the first outer surface is used to contact and connect with the busbar component of the battery.

[0013] The terminal body is connected to the connecting portion, contacting and connecting the busbar assembly to the first outer surface. This shortens the conductive path between the busbar assembly and the connecting portion, reducing resistance, heat generation, and temperature rise of the electrode terminals and busbar assembly, thereby improving the reliability of the battery cell. The terminal body is larger than the first limiting portion. Using the terminal body to connect to the busbar assembly reduces the risk of cracking of the electrode terminal during connection to the busbar assembly, thereby improving the reliability of the battery cell.

[0014] In some embodiments, the electrode terminal further includes a second limiting portion, which is located on a side of the wall portion facing the electrode assembly and protrudes from an outer peripheral surface of the terminal body.

[0015] The wall portion can be limited between the first limiting portion and the second limiting portion to limit the relative movement between the electrode terminal and the wall portion. When the battery is subjected to external impact, the force at the connection between the electrode terminal and the busbar component is reduced, thereby reducing the risk of battery failure.

[0016] In some embodiments, the battery cell further includes a cover plate, wherein the recess has an opening, the cover plate covers the opening and is connected to the electrode terminal. The cover plate can shield the connection portion, reduce the risk of corrosion of the connection portion by external impurities, and improve the stability and reliability of the connection between the connection portion and the components inside the housing.

[0017] In some embodiments, at least a portion of the cover plate is accommodated in the recess. Accommodating the cover plate in the recess can reduce the size of the outer surface of the cover plate protruding from the electrode terminal, thereby reducing the maximum size of the battery cell in the thickness direction of the wall, improving space utilization, and increasing the energy density of the battery.

[0018] In some embodiments, the cover plate is welded to the electrode terminal to form a second weld portion. The second weld portion does not protrude beyond the outer surface along the direction of the electrode assembly toward the wall. When the current collector contacts the outer surface, the second weld portion is less likely to come into contact with the collector, thereby reducing the risk of interference between the second weld portion and the collector, narrowing the gap between the collector and the outer surface, and increasing the flow area and connection strength between the collector and the electrode terminal.

[0019] In some embodiments, the cover plate is entirely accommodated in the recessed portion, and the cover plate has a third outer surface on a side distal to the connecting portion. In the thickness direction, the third outer surface is closer to the connecting portion than the outer surface. The second welded portion formed by welding is uneven and may protrude beyond the third outer surface. The third outer surface is positioned further inward relative to the outer surface, thereby reducing the risk of the second welded portion protruding beyond the outer surface in the thickness direction.

[0020] In some embodiments, the recess has an opening, the outer surface surrounds the opening, and the area of ​​the outer surface is larger than the area of ​​the opening. The outer surface has a larger area to increase the contact area between the outer surface and the flow-collecting component, improve the flow capacity, and reduce heat generation.

[0021] In some embodiments, the area of ​​the opening is greater than or equal to 0.01 times the area of ​​the outer surface, so that an external device can connect the connection portion to a component inside the housing via the opening.

[0022] In some embodiments, the area of ​​the opening is less than or equal to 0.34 times the area of ​​the outer surface, so as to reduce the area loss of the outer surface, increase the contact area between the outer surface and the flow-collecting component, improve the flow capacity, and reduce heat generation.

[0023] In some embodiments, the area of ​​the bottom surface of the recess is greater than or equal to 0.01 times the area of ​​the outer surface, so as to increase the area of ​​the connection portion, improve the flow capacity and connection strength between the connection portion and the components inside the shell, and improve the reliability of the battery cell.

[0024] In some embodiments, the area of ​​the bottom surface of the recess is less than or equal to 0.34 times the area of ​​the outer surface, so as to reduce the area loss of the outer surface, increase the contact area between the outer surface and the flow collecting component, improve the flow capacity, and reduce heat generation.

[0025] In some embodiments, the cross-sectional area of ​​the recess, perpendicular to the thickness, gradually decreases as it moves away from the outer surface. When the cover is placed into the recess, the side surfaces of the recess support and position the cover, thereby reducing assembly difficulty. Furthermore, the concave tapered structure of the recess improves the fit between the recess and the cover, while also allowing for greater dimensional tolerances.

[0026] In some embodiments, the housing includes a shell and an end cap, wherein the shell has a shell opening and the end cap covers the shell opening. The shell includes an integrally formed sidewall and end wall, wherein the sidewall surrounds the outer side of the electrode assembly and the end wall is disposed opposite the shell opening. The wall portion is an end cap or end wall. Because the end cap or end wall is flatter than the side wall, arranging the electrode terminal on the end cap or end wall can improve the assembly efficiency of the battery cell.

[0027] In some embodiments, the battery cell further includes a current collecting member connecting the tabs and the connecting portion.

[0028] In a second aspect, the present application provides a battery comprising a battery cell according to any embodiment of the first aspect and a current collecting component, wherein the current collecting component is in contact with and connected to an outer surface. At least a portion of the current can be transmitted directly between the electrode terminals and the current collecting component without passing through other components, thereby shortening the conductive path between the electrode terminals and the current collecting component, reducing resistance, and improving the battery's current carrying capacity.

[0029] In some embodiments, the electrode terminal is welded to the busbar to form a first weld, and the projection of the first weld and the recess in the thickness direction of the wall do not overlap. During the welding process, the electrode terminal can confine the molten liquid formed by the melted busbar, reducing the risk of the molten liquid flowing into the recess, and the possibility of the busbar being welded through and forming a through hole, thereby improving the current flow capacity of the first weld and enhancing the reliability of the battery cell.

[0030] In some embodiments, the wall portion is provided with an electrode lead-out hole, which extends through the wall portion along its thickness. The electrode terminal further comprises a terminal body and a first retaining portion. The outer surface of the electrode terminal comprises a first outer surface of the terminal body and a second outer surface of the first retaining portion. The recessed portion is recessed from the first outer surface toward the electrode assembly. The terminal body is at least partially accommodated in the electrode lead-out hole. The first retaining portion is located on a side of the wall portion facing away from the electrode assembly and is connected to the outer circumferential surface of the terminal body. The connecting portion is connected to the terminal body. The current collecting component contacts the first outer surface, and at least a portion of the first welding portion is formed on the terminal body.

[0031] Forming at least part of the first welding portion on the terminal body can make the first welding portion have a larger size in the thickness direction of the wall portion, thereby improving the connection strength between the busbar component and the electrode terminal, reducing the risk of separation between the busbar component and the electrode terminal, improving the flow capacity between the busbar component and the electrode terminal, and improving the reliability of the battery cell.

[0032] In some embodiments, the busbar component also contacts the second outer surface, and a portion of the first welding portion is formed on the first limiting portion to reduce the contact resistance between the first limiting portion and the busbar component, further improving the current flow capacity between the electrode terminal and the busbar component, reducing heat generation, and improving the reliability of the battery.

[0033] In some embodiments, the first welding portion includes a first welding mark and a second welding mark, the first welding mark is formed on the terminal body and the busbar component, and the second welding mark is formed on the first limiting portion and the busbar component. In the thickness direction, the maximum dimension of the first welding mark is greater than the maximum dimension of the second welding mark.

[0034] Compared with the second weld mark, the first weld mark has a larger size in the thickness direction, thereby improving the connection strength and current carrying capacity between the terminal body and the busbar component; compared with the first weld mark, the second weld mark has a smaller size in the thickness direction, thereby reducing the risk of the first limit part being melted through and improving the reliability of the battery cell.

[0035] In some embodiments, the battery cell further includes a cover plate, which is received in the recess and welded to the electrode terminal to form a second weld. The current collector does not overlap with the second weld in the thickness direction. When the current collector contacts the outer surface, the second weld is less likely to interfere with the current collector in the thickness direction, thereby reducing the gap between the current collector and the outer surface and increasing the flow area and connection strength between the current collector and the electrode terminal.

[0036] In some embodiments, the battery cell further includes a cover plate, which is received in the recess and welded to the electrode terminal to form a second weld. The current collector partially overlaps the second weld in the thickness direction, and a relief recess is provided on a side of the current collector facing the second weld to avoid the second weld.

[0037] By providing the avoidance recess, the risk of the second welding portion contacting the busbar component can be reduced, the gap between the busbar component and the outer surface can be reduced, and the flow area and connection strength between the busbar component and the electrode terminal can be improved.

[0038] In a third aspect, the present application provides an electrical device comprising a battery provided in any embodiment of the second aspect, the battery being used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The features, advantages and technical effects of exemplary embodiments of the present application will be described below with reference to the accompanying drawings.

[0040] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0041] FIG2 is a schematic diagram of an explosion of a battery provided in some embodiments of the present application;

[0042] FIG3 is a schematic structural diagram of the battery module shown in FIG2 ;

[0043] FIG4 is an exploded schematic diagram of a battery cell provided in some embodiments of the present application;

[0044] FIG5 is a schematic cross-sectional view of a battery cell and a busbar component provided in some embodiments of the present application;

[0045] FIG6 is an enlarged schematic diagram of the circle frame in FIG5;

[0046] FIG7 is a schematic cross-sectional view of an electrode terminal of a battery cell provided in some embodiments of the present application;

[0047] FIG8 is an enlarged schematic diagram of the box in FIG6;

[0048] FIG9 is a partial cross-sectional schematic diagram of a battery provided in some embodiments of the present application;

[0049] FIG10 is a partial cross-sectional schematic diagram of batteries provided in some other embodiments of the present application;

[0050] FIG11 is a partial cross-sectional schematic diagram of batteries provided in some other embodiments of the present application;

[0051] FIG12 is a partial cross-sectional schematic diagram of a battery provided in some further embodiments of the present application;

[0052] FIG13 is a schematic diagram of a battery cell provided in some further embodiments of the present application.

[0053] Detailed description of the drawings: 1. Vehicle; 2. Battery; 3. Controller; 4. Motor; 5. Housing; 5a. First housing portion; 5b. Second housing portion; 5c. Accommodation space; 6. Battery module; 7. Battery cell; 8. Current collector; 8a. Avoidance hole; 8b. Avoidance recess; 9. First welding portion; 9a. First weld mark; 9b. Second weld mark; 10. Electrode assembly; 11. Main body; 12. Tab; 20. Housing; 21. Housing; 211. Housing opening; 212. Side wall; 213. End wall; 22. End cap; 23. Wall portion; 231. Electrode lead-out hole; 30. Electrode terminal; 30a. Second welding portion; 30b. Third welding portion; 31. Outer surface; 32. Recess; 321. Opening; 322. Bottom surface; 33. Connecting portion; 34. Terminal body; 341. First outer surface; 342. Peripheral surface; 35. First limiting portion; 351. Second outer surface; 36. Second limiting portion; 40. Sealing member; 50. Insulating component; 60. Current collecting member; 70. Cover plate; 71. Third outer surface; Z, thickness direction. DETAILED DESCRIPTION

[0054] 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 and completely described below in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] The term "plurality" used in this application refers to two or more (including two).

[0062] 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.

[0063] The battery cell can be a lithium-ion battery cell, a sodium-ion battery cell, a sodium-lithium-ion battery cell, a lithium metal battery cell, a sodium metal battery cell, a lithium-sulfur battery cell, a magnesium-ion battery cell, a nickel-hydrogen battery cell, a nickel-cadmium battery cell, a lead-acid battery cell, etc., and the embodiments of the present application are not limited to this.

[0064] A battery cell generally includes an electrode assembly, which includes a positive electrode and a negative electrode.

[0065] 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. A separator is placed between the positive and negative electrodes to prevent a short circuit between the positive and negative electrodes while allowing the active ions to pass through.

[0066] 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.

[0067] 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.

[0068] 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 or stainless steel with a silver surface treatment, 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.).

[0069] 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 0.80 Co 0.15 Al 0.05 O2) and at least one of its modified compounds, etc.

[0070] In some embodiments, the positive electrode may be a metal foam or carbon foam. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, or the like. When the metal foam is used as the positive electrode, the surface of the metal foam may or may not be provided with a positive electrode active material. For example, a lithium source material, potassium metal, or sodium metal may be filled and / or deposited within the metal foam, where the lithium source material is lithium metal and / or a lithium-rich material.

[0071] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0072] As an example, the negative electrode current collector may be a metal foil, a metal foam, or a composite current collector. For example, the metal foil may be silver-surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam. The composite current collector may include a polymer 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, or silver alloy, etc.) on a polymer substrate (such as a substrate made of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0078] In some embodiments, the separator is a separator membrane. The separator membrane of the present application can be any well-known porous separator membrane with good chemical stability and mechanical stability.

[0079] For example, the primary material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. 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.

[0080] 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.

[0081] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be selected based on the application's needs. The electrolyte can be liquid, gel, or solid.

[0082] The liquid electrolyte includes an electrolyte salt and a solvent.

[0083] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0084] In some embodiments, the solvent can be selected from 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 can also be an ether solvent. Ether solvents can 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.

[0085] Among them, the gel electrolyte includes a skeleton network with a polymer as the electrolyte, combined with an ionic liquid-lithium salt.

[0086] Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0087] 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.

[0088] As an example, the inorganic solid electrolyte can be 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.

[0089] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0090] 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.

[0091] In some embodiments, the electrode assembly is a laminate structure.

[0092] 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.

[0093] 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.

[0094] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of stacked folded segments.

[0095] 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.

[0096] 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.

[0097] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0098] 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.

[0099] 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.

[0100] As an example, the battery cells may be cylindrical, prismatic, soft-pack or other shaped battery cells. Prismatic battery cells include square-shell, blade-shaped, and polygonal battery cells. Polygonal battery cells may be, for example, hexagonal.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0106] In some embodiments, a battery cell typically includes an electrode assembly, electrode terminals, and a housing. The electrode assembly is electrically connected to the outside world via the electrode terminals. The housing accommodates, protects, and supports the electrode assembly.

[0107] Generally, electrode terminals need to be connected to components within the housing to achieve electrical connection between the electrode terminals and the electrode assembly. These connections are typically made before installation into the housing. However, during this process, particles may attach to the electrode terminals. Once these particles enter the housing, they can easily puncture the separator and cause a short circuit, impacting the reliability of the battery cells.

[0108] Based on the above considerations, an embodiment of the present application provides a battery cell, which provides a recess on the electrode terminal to achieve connection between the electrode terminal and the components in the shell from the outside of the electrode terminal, thereby reducing particles entering the shell, reducing the risk of short circuit, and improving reliability.

[0109] The battery cells described in the embodiments of the present application are suitable for use in batteries and electrical devices using the batteries.

[0110] The battery cells disclosed in the embodiments of the present application can be used in electrical devices that use batteries as power sources or various energy storage systems that use batteries as energy storage elements. Electrical devices can include, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, battery-powered vehicles, electric vehicles, ships, spacecraft, and the like. Electric toys can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, among others.

[0111] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device.

[0112] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application.

[0113] As shown in FIG1 , a battery 2 is provided inside the vehicle 1. The battery 2 may be provided at the bottom, head, or tail of the vehicle 1. The battery 2 may be used to power the vehicle 1. For example, the battery 2 may serve as an operating power source for the vehicle 1.

[0114] The vehicle 1 may further include a controller 3 and a motor 4 . The controller 3 is used to control the battery 2 to supply power to the motor 4 , for example, to meet the power requirements of the vehicle 1 during startup, navigation, and driving.

[0115] In some embodiments of the present application, the battery 2 can not only serve as the operating power source of the vehicle 1, but also serve as the driving power source of the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0116] FIG2 is an exploded view of a battery according to some embodiments of the present application. As shown in FIG2 , the battery 2 includes a housing 5 and a battery cell (not shown in FIG2 ), wherein the battery cell is housed in the housing 5 .

[0117] The housing 5 is used to house battery cells and can have various structures. In some embodiments, the housing 5 can include a first housing portion 5a and a second housing portion 5b. The first housing portion 5a and the second housing portion 5b overlap each other, and the first housing portion 5a and the second housing portion 5b together define a storage space 5c for accommodating the battery cells. The second housing portion 5b can be a hollow structure with one end open. The first housing portion 5a is a plate-like structure, and the first housing portion 5a overlaps the open side of the second housing portion 5b to form the housing 5 with the storage space 5c. The first housing portion 5a and the second housing portion 5b can also be hollow structures with one end open. The open side of the first housing portion 5a overlaps the open side of the second housing portion 5b to form the housing 5 with the storage space 5c. Of course, the first housing portion 5a and the second housing portion 5b can have various shapes, such as a cylinder, a rectangular parallelepiped, etc.

[0118] In order to improve the sealing performance after the first box body 5a and the second box body 5b are connected, a sealing member, such as a sealant, a sealing ring, etc., may also be provided between the first box body 5a and the second box body 5b.

[0119] Assuming that the first box body portion 5a covers the top of the second box body portion 5b, the first box body portion 5a can also be called an upper box cover, and the second box body portion 5b can also be called a lower box body.

[0120] In battery 2, there can be one or more battery cells. If there are multiple battery cells, they can be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration refers to a combination of series and parallel connections. Multiple battery cells can be directly connected in series, in parallel, or in a hybrid configuration, and then the entire battery module can be housed within housing 5. Alternatively, multiple battery cells can be first connected in series, in parallel, or in a hybrid configuration to form a battery module 6, and then multiple battery modules 6 can be connected in series, in parallel, or in a hybrid configuration to form a single unit housed within housing 5.

[0121] A battery cell may be the smallest unit constituting a battery.

[0122] FIG3 is a schematic structural diagram of the battery module shown in FIG2 .

[0123] In some embodiments, as shown in FIG3 , there are multiple battery cells 7, which are first connected in series, in parallel, or in hybrid to form a battery module 6. The multiple battery modules 6 are then connected in series, in parallel, or in hybrid to form a whole, which is housed in a box.

[0124] In some embodiments, the battery module 6 includes a busbar 8 connected to the battery cells 7 .

[0125] For example, the multiple battery cells 7 of the battery module 6 can be electrically connected via a busbar 8 to achieve parallel, series, or mixed connection of the multiple battery cells 7 in the battery module 6. There can be one or more busbars 8, each of which is used to electrically connect at least two battery cells 7.

[0126] Figure 4 is an exploded schematic diagram of a battery cell provided in some embodiments of the present application; Figure 5 is a cross-sectional schematic diagram of a battery cell and a busbar component provided in some embodiments of the present application; Figure 6 is an enlarged schematic diagram of the circular frame of Figure 5; Figure 7 is a cross-sectional schematic diagram of the electrode terminals of a battery cell provided in some embodiments of the present application; and Figure 8 is an enlarged schematic diagram of the square frame of Figure 6.

[0127] 4 to 8 , an embodiment of the present application provides a battery cell 7 , which includes a housing 20 and an electrode assembly 10 , wherein the electrode assembly 10 is housed in the housing 20 .

[0128] The housing 20 may be a hollow structure, forming a cavity within it for accommodating the electrode assembly 10 and the electrolyte. The shape of the housing 20 may be determined based on the specific shape of the electrode assembly 10. For example, if the electrode assembly 10 is a rectangular parallelepiped structure, a rectangular housing may be used; if the electrode assembly 10 is a cylindrical structure, a cylindrical housing may be used.

[0129] In some embodiments, the housing 20 includes a shell 21 and an end cover 22 . The shell 21 has a shell opening 211 , and the end cover 22 covers the shell opening 211 .

[0130] The housing 21 is a component used to cooperate with the end cover 22 to form an internal cavity of the battery cell 7. The formed internal cavity can be used to accommodate the electrode assembly 10, electrolyte and other components.

[0131] The housing 21 and the end cap 22 may be separate components. For example, a housing opening 211 may be provided on the housing 21 , and the end cap 22 may cover the housing opening 211 at the housing opening 211 to form an internal cavity of the battery cell 7 .

[0132] The housing 21 can have various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the housing 21 can be determined according to the specific shape and size of the electrode assembly 10. The housing 21 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the present embodiment does not impose any particular limitation on this.

[0133] The shape of the end cap 22 can be adapted to the shape of the housing 21 to fit the housing 21. The material of the end cap 22 can be the same as or different from the material of the housing 21. Optionally, the end cap 22 can be made of a material with a certain hardness and strength (e.g., copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.). In this way, the end cap 22 is less likely to deform when subjected to compression or collision, thereby providing the battery cell 7 with higher structural strength and improved reliability.

[0134] The end cover 22 is connected to the housing 21 by welding, bonding, clamping or other methods.

[0135] In some embodiments, the housing 21 is a steel or aluminum housing. As an example, the housing 21 may be made of stainless steel, nickel-plated steel, or other materials with steel as the main body.

[0136] In some examples, one side of the housing 21 has a side housing opening 211, and one end cap 22 is provided and covers the housing 21. In other examples, both sides of the housing 21 have housing openings 211, and two end caps 22 are provided, and the two end caps 22 respectively cover the two housing openings 211 of the housing 21.

[0137] The electrode assembly 10 may be a component where electrochemical reactions occur in the battery cell 7. One or more electrode assemblies 10 may be contained within the housing 20.

[0138] As an example, the electrode assembly 10 includes a positive electrode sheet and a negative electrode sheet. The portions of the positive and negative electrode sheets containing active material constitute the main body 11 of the electrode assembly 10, while the portions of the positive and negative electrode sheets not containing active material each constitute a tab 12. The tabs 12 may include a positive tab and a negative tab. The positive and negative tabs may be located together at one end of the main body 11 or separately at opposite ends of the main body 11.

[0139] In some embodiments, the battery cell 7 further includes an electrode terminal 30 disposed on the housing 20 . The electrode terminal 30 can be used to electrically connect to the electrode assembly 10 to output or input electrical energy of the battery cell 7 .

[0140] Illustratively, the electrode terminal 30 may be provided on the end cover 22 or on the housing 21 .

[0141] In some embodiments, the electrode assembly 10 includes a tab 12 , and the electrode terminal 30 is electrically connected to the tab 12 .

[0142] During the charge and discharge process of the battery, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tab 12 is connected to the electrode terminal 30 to form a current loop.

[0143] In some embodiments, the battery cell 7 includes a housing 20, an electrode assembly 10, and an electrode terminal 30. The housing 20 includes a wall portion 23. The electrode assembly 10 is housed within the housing 20 and includes a tab 12. The electrode terminal 30 is disposed in the wall portion 23. The electrode terminal 30 has an outer surface 31 on a side of the wall portion away from the electrode assembly 10 along the thickness direction Z. The electrode terminal 30 is provided with a recessed portion 32 recessed from the outer surface 31. The electrode terminal 30 includes a connecting portion 33 disposed at the bottom of the recessed portion 32. The connecting portion 33 is electrically connected to the tab 12.

[0144] As an example, the wall portion 23 may be the end cover 22 or a wall of the housing 21 .

[0145] As an example, the shape of the wall portion 23 may be circular, rectangular, oval, or other shapes.

[0146] As an example, the tab 12 electrically connected to the electrode terminal 30 may be a positive tab or a negative tab.

[0147] As an example, the connection portion 33 can be directly connected to the electrode terminal 30, for example, by welding, abutting, or other means to connect the electrode terminal 30, so as to achieve electrical connection between the tab 12 and the electrode terminal 30. Alternatively, the connection portion 33 can also be indirectly connected to the electrode terminal 30 through other conductive components (such as a current collecting member) to achieve electrical connection between the tab 12 and the electrode terminal 30.

[0148] As an example, the outer surface 31 may be a plane or a curved surface. Optionally, the outer surface 31 is a plane perpendicular to the thickness direction Z.

[0149] As an example, in the thickness direction Z, the projection of the outer surface 31 may surround the projection of the recess 32 ; alternatively, in the thickness direction Z, the projection of the outer surface 31 may be connected to a portion of the edge of the projection of the recess 32 .

[0150] In the embodiment of the present application, by providing the recess 32, the size of the connecting portion 33 in the thickness direction Z can be reduced, which facilitates the connection between the connecting portion 33 and the components inside the shell 20 from the outside of the connecting portion 33, reduces the risk of particles remaining on the connecting portion 33 entering the interior of the shell 20, and improves reliability.

[0151] For example, by providing the recess 32, the size of the connecting portion 33 in the thickness direction Z can be reduced, and welding can be performed from the outside of the connecting portion 33 to achieve welding of the connecting portion 33 with components inside the shell 20; during welding, the shell can block the metal particles generated by welding, thereby reducing the risk of particles entering the interior of the shell 20 and improving reliability.

[0152] In some embodiments, the connection portion 33 may be connected to components inside the housing 20 by welding.

[0153] In some embodiments, the outer surface 31 of the electrode terminal 30 is configured to contact and connect with the busbar 8 of the battery.

[0154] As an example, the electrode terminal 30 and the current collecting member 8 may be connected by clamping, welding or other methods.

[0155] The outer surface 31 of the electrode terminal 30 is in direct contact with and connected to the busbar component 8. At least part of the current can be transmitted directly between the electrode terminal 30 and the busbar component 8 without passing through other components, thereby shortening the conductive path between the electrode terminal 30 and the busbar component 8, reducing resistance, and improving the battery's current capacity.

[0156] In some embodiments, the electrode terminal 30 is welded to the busbar 8 to form a first weld 9. The first weld 9 formed by welding can reduce the resistance between the electrode terminal 30 and the busbar 8, improve the current carrying capacity, and increase the connection strength between the electrode terminal 30 and the busbar 8.

[0157] As an example, the electrode terminal 30 is connected to the busbar member 8 by ultrasonic welding, laser welding or other welding methods.

[0158] Optionally, the electrode terminal 30 is connected to the busbar 8 by laser welding. For example, laser is irradiated on the busbar 8, and a portion of the busbar 8 and a portion of the electrode terminal 30 melt to form a molten pool, which solidifies to form the first weld 9.

[0159] As an example, the first welding portion 9 may include at least one of a point-shaped weld mark, a line-shaped weld mark, a C-shaped weld mark, a V-shaped weld mark, and a spiral-shaped weld mark.

[0160] In some embodiments, the busbar member 8 partially overlaps with the electrode terminal 30 in the thickness direction Z, and the overlapping portions of the busbar member 8 and the electrode terminal 30 are welded to form a first weld portion 9 .

[0161] In some embodiments, the projections of the first welding portion 9 and the recess 32 in the wall thickness direction Z do not overlap. During the welding process, the electrode terminal 30 can limit the molten liquid formed after the current collecting component 8 melts, reducing the risk of the molten liquid flowing into the recess 32, and reducing the possibility of the current collecting component 8 being welded through and forming a through hole, thereby improving the current flow capacity of the first welding portion 9 and enhancing the reliability of the battery cell 7.

[0162] In some embodiments, the polarity of the wall portion 23 is opposite to the polarity of the electrode terminal 30. Optionally, the electrode terminal 30 is electrically connected to the positive tab, and the wall portion 23 is electrically connected to the negative tab.

[0163] In some embodiments, the wall portion 23 is provided with an electrode lead-out hole 231 , and the electrode lead-out hole 231 passes through the wall portion 23 along the thickness direction Z.

[0164] Illustratively, the electrode lead-out hole 231 passes through the wall portion 23 , so that the electrode terminal 30 can lead the electrical energy of the electrode assembly 10 to the outside of the housing 20 .

[0165] The central axis of the electrode lead-out hole 231 may be parallel to the thickness direction Z, or may form a certain angle with the thickness direction Z.

[0166] In some embodiments, the electrode terminal 30 is disposed on the wall portion 23 and covers at least a portion of the electrode lead-out hole 231 .

[0167] The electrode terminal 30 may cover only a portion of the electrode lead-out hole 231 or may completely cover the electrode lead-out hole 231. As an example, the electrode terminal 30 may alone seal the electrode lead-out hole 231 to isolate the interior space of the housing 20 from the exterior space, thereby improving the sealing of the battery cell 7. Alternatively, the electrode terminal 30 may cooperate with other functional components (e.g., a sealant) to jointly seal the electrode lead-out hole 231 to isolate the interior space of the housing 20 from the exterior space, thereby improving the sealing of the battery cell 7.

[0168] In some embodiments, the electrode terminal 30 also includes a terminal body 34 and a first limiting portion 35. The outer surface 31 of the electrode terminal 30 includes a first outer surface 341 of the terminal body 34 and a second outer surface 351 of the first limiting portion 35. The recess 32 is recessed from the first outer surface 341 toward the electrode assembly 10. The terminal body 34 is at least partially accommodated in the electrode lead-out hole 231. The first limiting portion 35 is located on the side of the wall 23 away from the electrode assembly 10 and is connected to the outer peripheral surface 342 of the terminal body 34. The connecting portion 33 is connected to the terminal body 34.

[0169] As an example, the terminal body 34 and the first limiting portion 35 can be an integrally formed structure; alternatively, the terminal body 34 and the first limiting portion 35 are formed independently of each other and are connected by snapping, welding, bonding or other means.

[0170] As an example, the first outer surface 341 and the second outer surface 351 may be coplanar or non-coplanar. Optionally, the first outer surface 341 and the second outer surface 351 are in the same plane; optionally, the first outer surface 341 and the second outer surface 351 are both perpendicular to the thickness direction Z.

[0171] As an example, the connection portion 33 and the terminal body 34 jointly define a recess 32 .

[0172] The first limiting portion 35 may be one or more. Optionally, the first limiting portion 35 is one and has a circular ring structure. The first limiting portion 35 may be multiple and spaced apart along the circumference of the terminal body 34 .

[0173] By configuring the terminal body 34 to extend into the electrode lead-out hole 231, it is possible to facilitate connection between the connecting portion 33 and other components within the housing 20. The wall portion 23 can block the first stopper 35, thereby reducing the risk of the electrode terminal 30 falling into the housing 20 through the electrode lead-out hole 231.

[0174] In some embodiments, the terminal body 34 surrounds the connecting portion 33 .

[0175] In some embodiments, along the thickness direction Z of the wall, the size of the terminal body 34 is larger than that of the first limiting portion 35 , and the first outer surface 341 is used to contact and connect with the busbar component 8 of the battery.

[0176] Exemplarily, along the thickness direction Z of the wall portion, the minimum dimension of the terminal body 34 is greater than the maximum dimension of the first limiting portion 35 .

[0177] The second outer surface 351 may be connected to the flow-collecting component 8 or may not be connected to the flow-collecting component 8 .

[0178] The terminal body 34 is connected to the connecting portion 33, contacting and connecting the busbar 8 to the first outer surface 341. This shortens the conductive path between the busbar 8 and the connecting portion 33, reducing resistance, heat generation, and the temperature rise of the electrode terminal 30 and the busbar 8, thereby improving the reliability of the battery cell 7. The terminal body 34 is larger than the first limiting portion 35. Using the terminal body 34 to connect to the busbar 8 can reduce the risk of cracking of the electrode terminal 30 when connected to the busbar 8, thereby improving the reliability of the battery cell 7.

[0179] In some embodiments, the current collecting component 8 is welded to the terminal body 34. The terminal body 34 has a large dimension in the thickness direction Z of the wall portion. Welding the current collecting component 8 to the terminal body 34 can reduce the risk of the electrode terminal 30 being welded through.

[0180] In some embodiments, the current collecting member 8 contacts the first outer surface 341 , and at least a portion of the first welding portion 9 is formed on the terminal body 34 .

[0181] In the thickness direction Z, the projection of the first welding portion 9 may be entirely located within the projection of the terminal body 34 , or may be only partially located within the projection of the terminal body 34 .

[0182] Forming at least a portion of the first welding portion 9 on the terminal body 34 can make the first welding portion 9 have a larger size in the thickness direction Z of the wall portion, thereby improving the connection strength between the busbar component 8 and the electrode terminal 30, reducing the risk of separation between the busbar component 8 and the electrode terminal 30, improving the flow capacity between the busbar component 8 and the electrode terminal 30, and improving the reliability of the battery cell 7.

[0183] In some embodiments, the busbar component 8 is further in contact with the second outer surface 351 to increase the contact area between the busbar component 8 and the electrode terminal 30 and reduce the resistance.

[0184] In some embodiments, a portion of the first welding portion 9 is formed on the first limiting portion 35 to reduce the contact resistance between the first limiting portion 35 and the busbar component 8, further improving the flow capacity between the electrode terminal 30 and the busbar component 8, reducing heat generation, and improving the reliability of the battery.

[0185] In some embodiments, the first welding portion 9 includes a first welding mark 9 a and a second welding mark 9 b . The first welding mark 9 a is formed on the terminal body 34 and the busbar component 8 , and the second welding mark 9 b is formed on the first limiting portion 35 and the busbar component 8 .

[0186] Exemplarily, the projection of the first weld mark 9a along the thickness direction Z is located within the projection of the terminal body 34 along the thickness direction Z, and the projection of the second weld mark 9b along the thickness direction Z is located within the projection of the first limiting portion 35 along the thickness direction Z.

[0187] The first weld mark 9a may be one or more, and the second weld mark 9b may be one or more.

[0188] The first weld mark 9a and the second weld mark 9b can both transmit current between the electrode terminal 30 and the busbar component 8, thereby improving the flow capacity between the electrode terminal 30 and the busbar component 8, reducing heat generation, and improving battery reliability.

[0189] In some embodiments, the maximum dimension of the first weld mark 9a is greater than the maximum dimension of the second weld mark 9b in the thickness direction Z. Compared to the second weld mark 9b, the first weld mark 9a has a larger dimension in the thickness direction Z, thereby improving the connection strength and current carrying capacity between the terminal body 34 and the current collecting component 8. Compared to the first weld mark 9a, the second weld mark 9b has a smaller dimension in the thickness direction Z, thereby reducing the risk of the first limiter 35 being melted through and improving the reliability of the battery cell 7.

[0190] In some embodiments, in the thickness direction Z, the maximum dimension of the first weld mark 9 a is greater than the dimension of the first limiting portion 35 .

[0191] In some embodiments, the electrode terminal 30 further includes a second limiting portion 36 , which is located on a side of the wall portion 23 facing the electrode assembly 10 and protrudes from an outer peripheral surface 342 of the terminal body 34 .

[0192] As an example, the terminal body 34 and the second limiting portion 36 can be an integrally formed structure; alternatively, the terminal body 34 and the second limiting portion 36 are formed independently of each other and are connected by snapping, welding, bonding or other means.

[0193] The wall portion 23 can be limited between the first limiting portion 35 and the second limiting portion 36 to limit the relative movement between the electrode terminal 30 and the wall portion 23. When the battery is subjected to external impact, the force at the connection between the electrode terminal 30 and the busbar component 8 is reduced, thereby reducing the risk of battery failure.

[0194] In some embodiments, the second limiting portion 36 and the wall portion 23 have an overlapping area in the thickness direction Z. Optionally, in the radial direction of the electrode lead-out hole 231 , the width L of the overlapping area between the second limiting portion 36 and the wall portion 23 is 1.5 mm-5 mm.

[0195] The radial direction of the electrode lead-out hole 231 may be a direction passing through the central axis of the electrode lead-out hole 231 and perpendicular to the central axis of the electrode lead-out hole 231. Optionally, the central axis of the electrode lead-out hole 231 is parallel to the thickness direction Z of the wall portion.

[0196] Limiting L to 1.5 mm or greater reduces the risk of the electrode terminal 30 detaching from the wall portion 23 through the electrode lead-out hole 231. Limiting L to 5 mm or less reduces the space and weight occupied by the second stopper 36, improves energy density, and reduces the difficulty of manufacturing the electrode terminal 30.

[0197] Exemplarily, the overlapping area between the second limiting portion 36 and the wall portion 23 is annular, and the width L is the ring width of the overlapping area.

[0198] Illustratively, L is 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, or 5 mm.

[0199] In some embodiments, the terminal body 34, the first stopper 35, the second stopper 36, and the connecting portion 33 are integrally formed to reduce resistance to current transmission within the electrode terminal 30 and reduce the resistance between the current collecting component 8 and the tab 12. This embodiment of the present application can also improve the overall structural strength of the electrode terminal 30.

[0200] In some embodiments, in the radial direction of the electrode lead-out hole 231 , the end of the first limiting portion 35 away from the terminal body 34 exceeds the end of the second limiting portion 36 away from the terminal body 34 .

[0201] In the radial direction of the electrode lead-out hole 231, the first limiting portion 35 has a larger size than the second limiting portion 36, which can increase the exposed area of ​​the electrode terminal 30, facilitate the contact between the electrode terminal 30 and the external current collecting component 8, increase the connection area between the electrode terminal 30 and the current collecting component 8, and improve the current flow capacity.

[0202] In some embodiments, the battery cell 7 further includes a seal 40 , at least a portion of which is disposed between the second limiting portion 36 and the wall portion 23 .

[0203] As an example, the electrode terminal 30 and the sealant 40 together separate the inner space and the outer space of the outer case 20 to improve the sealing performance of the battery cell 7 .

[0204] The sealing member 40 can fill the gap between the second limiting portion 36 and the wall portion 23 to seal the electrode lead-out hole 231 .

[0205] In some embodiments, the portion of the sealing member 40 sandwiched between the second limiting portion 36 and the wall portion 23 is compressed to seal the electrode lead-out hole 231 .

[0206] In some embodiments, a portion of the sealing member 40 is disposed between the first limiting portion 35 and the wall portion 23 .

[0207] In some embodiments, a portion of the sealing member 40 is disposed in the electrode lead-out hole 231 and separates the hole wall of the electrode lead-out hole 231 from the terminal body 34 .

[0208] In some embodiments, the sealant 40 is made of an insulating material and can insulate the wall portion 23 from the electrode terminal 30 .

[0209] In some embodiments, the battery cell 7 further includes an insulating component 50 , which is disposed on a surface of the wall portion 23 facing the electrode assembly 10 . The insulating component 50 can be used to insulate at least a portion of the electrode assembly 10 from the wall portion 23 .

[0210] In some embodiments, the projection of the wall portion 23 along the thickness direction Z is annular. Optionally, the battery cell 7 is a cylindrical battery cell.

[0211] In some embodiments, the housing 21 includes a sidewall 212 and an end wall 213. The sidewall 212 surrounds the outside of the electrode assembly 10, and the end wall 213 is disposed opposite the housing opening 211. The wall portion 23 is an end cap 22 or an end wall 213. Exemplarily, the sidewall 212 and the end wall 213 are integrally formed.

[0212] There may be one or more sidewalls 212. In some examples, there may be one sidewall 212 and it may be a cylindrical structure. In other examples, there may be multiple sidewalls 212, which are sequentially connected along the circumference of the electrode assembly 10. For example, there may be four sidewalls 212, which are sequentially connected to form a square cylindrical structure.

[0213] In some embodiments, the battery cell 7 is a cylindrical battery cell with a single cylindrical sidewall 212. Because the end cap 22 or end wall 213 is flatter than the sidewall 212, disposing the electrode terminal 30 on the end cap 22 or end wall 213 can improve the assembly efficiency of the battery cell 7.

[0214] In some embodiments, the housing 21 is an integrally formed structure, and the wall portion 23 is an end wall 213 .

[0215] In some embodiments, the battery cell 7 further includes a current collecting member 60 , which connects the electrode tab 12 and the connecting portion 33 .

[0216] The current collecting member 60 can be connected to the electrode tab 12 by welding, abutting, bonding or other means, and connected to the connecting portion 33 by welding, abutting, bonding or other means to achieve electrical connection between the electrode terminal 30 and the electrode tab 12 .

[0217] The current collecting member 60 is made of a conductive material, for example, the current collecting member 60 is made of a conductive metal.

[0218] In some embodiments, a surface of the current collecting member 60 facing away from the wall portion 23 abuts against the electrode tab 12 , and a surface of the current collecting member 60 facing the wall portion 23 abuts against the connecting portion 33 .

[0219] In some embodiments, the current collecting member 60 is welded to the electrode tab 12. For example, the current collecting member 60 is connected to the electrode tab 12 by ultrasonic welding, laser welding, or other welding methods.

[0220] In some embodiments, the current collecting member 60 is welded to the connection portion 33. As an example, the current collecting member 60 is connected to the connection portion 33 by laser welding, resistance welding, ultrasonic torque welding or other welding methods.

[0221] In some embodiments, the battery cell 7 further includes a cover plate 70 . The recess 32 has an opening 321 . The cover plate 70 covers the opening 321 and is connected to the electrode terminal 30 .

[0222] Exemplarily, the cover plate 70 is used to separate the connection portion 33 from the space outside the cover plate 70 .

[0223] Illustratively, at least a portion of the cover plate 70 extends into the opening 321 to cover the opening 321 ; alternatively, the cover plate 70 may be entirely located outside the opening 321 and cover the opening 321 in the thickness direction Z.

[0224] The cover plate 70 can shield the connection portion 33 , reduce the risk of the connection portion 33 being corroded by external impurities, and improve the stability and reliability of the connection between the connection portion 33 and components inside the housing 20 .

[0225] The current collecting component 8 is directly connected to the electrode terminal 30 and does not need to be connected to the cover plate 70 , thereby shortening the conductive path between the electrode tab 12 and the current collecting component 8 and reducing resistance.

[0226] In some embodiments, at least a portion of the cover plate 70 is accommodated in the recess 32. By accommodating the cover plate 70 in the recess 32, the extent of the cover plate 70 protruding from the outer surface 31 of the electrode terminal 30 can be reduced, thereby reducing the maximum dimension of the battery cell 7 in the thickness direction Z of the wall, improving space utilization, and increasing the energy density of the battery.

[0227] In some embodiments, the cap plate 70 is welded to the electrode terminal 30 and forms a second welding portion 30 a .

[0228] For example, the second welding portion 30 a can seal the space between the cover plate 70 and the connecting portion 33 , thereby reducing the risk of corrosion of the connecting portion 33 .

[0229] Illustratively, the cap plate 70 is connected to the electrode terminal 30 by laser welding.

[0230] Illustratively, the current collecting member 8 is connected to the electrode terminal 30 , thereby reducing the current flowing through the second welding portion 30 a , lowering heat generation, and improving the reliability of the battery cell 7 .

[0231] In some embodiments, the second welding portion 30a is annular.

[0232] In some embodiments, the cover plate 70 is welded to the terminal body 34 .

[0233] In some embodiments, along the direction of the electrode assembly 10 pointing toward the wall portion 23 , the second welding portion 30 a does not protrude from the outer surface 31 .

[0234] Exemplarily, “a direction pointing toward the wall portion 23 along the electrode assembly 10 ” is parallel to the thickness direction Z of the wall portion.

[0235] When the busbar component 8 contacts the outer surface 31, the second welding portion 30a is not easy to contact the busbar component 8, thereby reducing the risk of interference between the second welding portion 30a and the busbar component 8, reducing the gap between the busbar component 8 and the outer surface 31, and improving the flow area and connection strength between the busbar component 8 and the electrode terminal 30.

[0236] In some embodiments, along the direction of the electrode assembly 10 pointing toward the wall portion 23 , the second welding portion 30 a is spaced apart from the outer surface 31 by a predetermined distance, so as to further reduce the risk of interference between the second welding portion 30 a and the current collecting component 8 .

[0237] In some embodiments, the cover plate 70 is entirely accommodated in the recess 32 . The cover plate 70 has a third outer surface 71 on a side away from the connecting portion 33 . In the thickness direction Z, the third outer surface 71 is closer to the connecting portion 33 than the outer surface 31 .

[0238] The second weld portion 30a formed by welding is uneven and may protrude from the third outer surface 71. The third outer surface 71 is located further inward relative to the outer surface 31, thereby reducing the risk of the second weld portion 30a protruding from the outer surface 31 in the thickness direction Z.

[0239] In some embodiments, the connection portion 33 is welded to the current collecting member 60 or the tab 12 to form a third welding portion 30 b.

[0240] In some embodiments, the connection portion 33 is laser welded to the current collecting member 60 or the tab 12. The recess 32 can reduce the thickness of the connection portion 33. Laser action on the connection portion 33 from the outside reduces the risk of metal particles entering the interior of the housing 20.

[0241] In some embodiments, the cover plate 70 may separate the third welding portion 30 b from the space outside the cover plate 70 , thereby reducing the risk of the third welding portion 30 b being corroded by impurities.

[0242] In some embodiments, in the thickness direction Z, the third welding portion 30 b is spaced apart from the cover plate 70 to reduce the risk of the cover plate 70 crushing the third welding portion 30 b.

[0243] In some embodiments, the area of ​​the cross section of the recess 32 perpendicular to the thickness direction Z gradually decreases in a direction away from the outer surface 31 .

[0244] When the cover plate 70 is placed in the recess 32, the side surfaces of the recess 32 can support and position the cover plate 70, thereby reducing the difficulty of assembling the cover plate 70. In addition, the tapered structure of the recess 32 can also improve the fit between the recess 32 and the cover plate 70, while also allowing for a larger dimensional tolerance.

[0245] For example, the recess 32 may be in the shape of an inverted pyramid or an inverted truncated cone.

[0246] For example, the side surface of the recess 32 can limit the cover plate 70 so that the cover plate 70 is spaced apart from the third welding portion 30 b.

[0247] In some embodiments, the recess 32 has an opening 321 , and the outer surface 31 surrounds the opening 321 . The area of ​​the outer surface 31 is larger than that of the opening 321 .

[0248] The outer surface 31 has a larger area to increase the contact area between the outer surface 31 and the flow collecting component 8, improve the flow capacity, and reduce heat generation.

[0249] In some embodiments, the outer surface 31 is a circular plane, the opening 321 is a circle, the outer diameter of the outer surface 31 is D0, and the diameter of the opening 321 is D1.

[0250] For example, the area of ​​the opening 321 is π×(D1 / 2) 2 The area of ​​the outer surface 31 is π×(D0 / 2) 2 -π×(D1 / 2) 2 .

[0251] In some embodiments, the area of ​​the opening 321 is greater than or equal to 0.01 times the area of ​​the outer surface 31 , so that an external device can connect the connection portion 33 to components inside the housing 20 via the opening 321 .

[0252] In some embodiments, the area of ​​the opening 321 is less than or equal to 0.34 times the area of ​​the outer surface 31 to reduce the area loss of the outer surface 31, increase the contact area between the outer surface 31 and the flow-collecting component 8, improve the flow capacity, and reduce heat generation.

[0253] In some embodiments, the area of ​​the opening 321 is 0.01 times, 0.02 times, 0.05 times, 0.08 times, 0.1 times, 0.15 times, 0.2 times, 0.25 times, 0.3 times, or 0.34 times the area of ​​the outer surface 31 .

[0254] In some embodiments, D1 is greater than or equal to 0.1 times D0 and less than or equal to 0.5 times D0. Alternatively, D1 is greater than or equal to 0.2 times D0 and less than or equal to 0.4 times D0.

[0255] In some embodiments, the bottom surface 322 of the recess 32 corresponds to the connecting portion 33 , that is, the portion of the electrode terminal 30 corresponding to the bottom surface 322 of the recess 32 along the thickness direction Z is the connecting portion 33 .

[0256] In some embodiments, the area of ​​the bottom surface 322 of the recess 32 is greater than or equal to 0.01 times the area of ​​the outer surface 31, thereby increasing the area of ​​the connection portion 33, improving the flow capacity and connection strength between the connection portion 33 and the components inside the housing 20, and improving the reliability of the battery cell 7. For example, in embodiments of the present application, the area of ​​the third welding portion 30b can be increased, thereby improving the flow capacity between the connection portion 33 and the tab 12.

[0257] In some embodiments, the area of ​​the bottom surface 322 of the recess 32 is less than or equal to 0.34 times the area of ​​the outer surface 31, thereby reducing the area loss of the outer surface 31, increasing the contact area between the outer surface 31 and the flow-collecting component 8, improving the flow capacity, and reducing heat generation. For example, the embodiment of the present application reduces the area occupied by the recess 32 to meet the welding area requirements of the flow-collecting component 8.

[0258] In some embodiments, the area of ​​the bottom surface 322 of the recess 32 is 0.01 times, 0.02 times, 0.05 times, 0.08 times, 0.1 times, 0.15 times, 0.2 times, 0.25 times, 0.3 times, or 0.34 times the area of ​​the outer surface 31 .

[0259] In some embodiments, the area of ​​the bottom surface 322 of the recess 32 is smaller than or equal to the area of ​​the opening 321 . Alternatively, the area of ​​the bottom surface 322 of the recess 32 is smaller than the area of ​​the opening 321 .

[0260] For example, the bottom surface 322 of the recess 32 is circular, the diameter of the bottom surface 322 of the recess 32 is D2, and the area of ​​the bottom surface 322 of the recess 32 is π×(D2 / 2). 2 .

[0261] In some embodiments, D2 is greater than or equal to 0.1 times D0 and less than or equal to 0.5 times D0. Alternatively, D2 is greater than or equal to 0.2 times D0 and less than or equal to 0.4 times D0.

[0262] In some embodiments, the connection portion 33 is connected to the current collecting member 60 by laser welding, and forms the third welding portion 30 b .

[0263] FIG9 is a schematic partial cross-sectional view of a battery provided in some embodiments of the present application.

[0264] 9 , in some embodiments, in the thickness direction Z, the current collecting member 8 does not overlap with the second welding portion 30 a.

[0265] In the thickness direction Z, the flow collecting component 8 and the cover plate 70 may or may not overlap.

[0266] In the thickness direction Z, the second welding portion 30 a may or may not protrude from the outer surface 31 .

[0267] When the busbar component 8 contacts the outer surface 31, the second welding portion 30a is not easy to interfere with the busbar component 8 in the thickness direction Z, thereby reducing the gap between the busbar component 8 and the outer surface 31 and improving the flow area and connection strength between the busbar component 8 and the electrode terminal 30.

[0268] FIG10 is a schematic partial cross-sectional view of batteries provided in some other embodiments of the present application.

[0269] As shown in FIG. 10 , in some embodiments, the collecting member 8 partially overlaps with the cover plate 70 in the thickness direction Z.

[0270] In some embodiments, the second welding portion 30a protrudes from the outer surface 31 in the thickness direction Z. The confluence member 8 may be provided with an avoidance hole 8a for avoiding the second welding portion 30a so that the confluence member 8 and the second welding portion 30a do not overlap in the thickness direction Z.

[0271] In some embodiments, the conduit component 8 is spaced apart from the cover plate 70 in the thickness direction Z to reduce the risk of the conduit component 8 contacting the outer surface 31 and the third outer surface 71 at the same time, thereby reducing over-positioning.

[0272] FIG11 is a schematic partial cross-sectional view of a battery provided in some other embodiments of the present application.

[0273] 11 , in some embodiments, the current collecting component 8 partially overlaps the second welding portion 30a in the thickness direction Z. A side of the current collecting component 8 facing the second welding portion 30a is provided with an avoidance recess 8b for avoiding the second welding portion 30a.

[0274] By providing the avoidance recess 8b, the risk of the second welding portion 30a contacting the busbar component 8 can be reduced, the gap between the busbar component 8 and the outer surface 31 can be reduced, and the flow area and connection strength between the busbar component 8 and the electrode terminal 30 can be improved.

[0275] FIG12 is a schematic partial cross-sectional view of a battery provided in some further embodiments of the present application.

[0276] 12 , in some embodiments, the terminal body 34 and the second limiting portion 36 are two independently formed components, and the two components are fixedly connected.

[0277] In some embodiments, the second limiting portion 36 is a ring-shaped member.

[0278] For example, the terminal body 34 is inserted into the electrode lead-out hole 231 from the outside of the wall portion 23, and the second stopper 36 can be sleeved onto the terminal body 34 from the inside of the wall portion 23. After the second stopper 36 is sleeved onto the terminal body 34, the terminal body 34 is squeezed to deform and form a flange structure, thereby riveting the terminal body 34 to the second stopper 36.

[0279] FIG13 is a schematic diagram of a battery cell provided in some further embodiments of the present application.

[0280] 13 , in some embodiments, the battery cell 7 is a square battery cell. In some embodiments, the wall portion 23 is an end cap 22 .

[0281] According to some embodiments of the present application, the present application further provides a battery comprising a plurality of battery cells 7 according to any one of the above embodiments.

[0282] According to some embodiments of the present application, the present application further provides an electrical device comprising a battery according to any of the above embodiments, the battery being used to provide electrical energy to the electrical device. The electrical device may be any of the aforementioned devices or systems using the battery.

[0283] 4 to 8 , an embodiment of the present application provides a battery cell 7 , which includes a housing 20 , an electrode assembly 10 , an electrode terminal 30 , a cap plate 70 , and a current collecting member 60 .

[0284] The housing 20 includes a shell 21 and an end cap 22. The shell 21 has a shell opening 211. The end cap 22 covers the shell opening 211. The end cap 22 and the shell 21 cooperate to form an internal cavity, and the electrode assembly 10 is accommodated in the internal cavity.

[0285] The housing 21 includes a side wall 212 and an end wall 213 . The side wall 212 surrounds the outer side of the electrode assembly 10 , and the end wall 213 is disposed opposite to the housing opening 211 . The end wall 213 is provided with an electrode lead-out hole 231 .

[0286] The electrode assembly 10 includes a tab 12 , and the current collecting member 60 is located between the tab 12 and the end wall 213 and connected to the tab 12 .

[0287] The electrode terminal 30 includes a terminal body 34, a first stopper 35, a second stopper 36, and a connecting portion 33. The terminal body 34 is at least partially accommodated in the electrode lead-out hole 231. The first stopper 35 is located on the side of the wall 23 facing away from the electrode assembly 10 and is connected to the outer peripheral surface 342 of the terminal body 34. The second stopper 36 is located on the side of the wall 23 facing the electrode assembly 10 and protrudes from the outer peripheral surface 342 of the terminal body 34.

[0288] The first outer surface 341 of the terminal body 34 and the second outer surface 351 of the first retaining portion 35 are coplanar. The electrode terminal 30 is provided with a recess 32 that is recessed from the first outer surface 341 toward the electrode assembly 10. The connecting portion 33 is connected to the terminal body 34, and the connecting portion 33 and the terminal body 34 together define the recess 32.

[0289] The connection portion 33 is welded to the current collecting member 60 . At least a portion of the cap plate 70 is received in the recess 32 and welded to the terminal body 34 .

[0290] The electrode terminal 30 is welded to the busbar component 8 to form a first weld portion 9. The busbar component 8 contacts both the first outer surface 341 and the second outer surface 351. The first weld portion 9 includes a first weld mark 9a and a second weld mark 9b. The first weld mark 9a is formed between the terminal body 34 and the busbar component 8, while the second weld mark 9b is formed between the first stopper 35 and the busbar component 8. In the thickness direction Z, the maximum dimension of the first weld mark 9a is greater than the maximum dimension of the second weld mark 9b.

[0291] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and components may be replaced with equivalents without departing from the scope of the present application. In particular, the various technical features described in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions within the scope of the claims.

Claims

1. A battery cell, comprising: a housing including a wall portion; an electrode assembly housed in the housing and comprising a tab; An electrode terminal is arranged on the wall portion, and the electrode terminal has an outer surface on a side away from the electrode assembly along the thickness direction of the wall portion. The electrode terminal is provided with a recessed portion recessed from the outer surface, and the electrode terminal includes a connecting portion arranged at the bottom of the recess, and the connecting portion is electrically connected to the electrode ear.

2. The battery cell according to claim 1, wherein: The outer surface of the electrode terminal is used to contact and connect with the busbar of the battery.

3. The battery cell according to claim 2, wherein: The electrode terminal is used to be welded to the busbar component to form a first welding portion, and the first welding portion and the recessed portion do not overlap when projected in the thickness direction of the wall portion.

4. The battery cell according to any one of claims 1 to 3, wherein: The wall portion is provided with an electrode lead-out hole, and the electrode lead-out hole passes through the wall portion along the thickness direction; The electrode terminal also includes a terminal body and a first limiting portion. The outer surface of the electrode terminal includes a first outer surface of the terminal body and a second outer surface of the first limiting portion. The recess is recessed from the first outer surface toward the electrode assembly. The terminal body is at least partially accommodated in the electrode lead-out hole. The first limiting portion is located on the side of the wall portion facing away from the electrode assembly and is connected to the outer peripheral surface of the terminal body. The connecting portion is connected to the terminal body.

5. The battery cell according to claim 4, wherein: Along the thickness direction of the wall portion, the size of the terminal body is larger than the size of the first limiting portion, and the first outer surface is used to contact and connect with the current collecting component of the battery.

6. The battery cell according to claim 4 or 5, wherein: The electrode terminal further includes a second limiting portion, which is located on a side of the wall portion facing the electrode assembly and protrudes from an outer peripheral surface of the terminal body. 7 . The battery cell according to claim 1 , further comprising a cover plate, wherein the recess has an opening, and the cover plate covers the opening and is connected to the electrode terminal.

8. The battery cell according to claim 7, wherein: At least a portion of the cover plate is accommodated in the recess.

9. The battery cell according to claim 7 or 8, wherein: The cover plate is welded to the electrode terminal to form a second welding portion; Along a direction in which the electrode assembly points toward the wall, the second welding portion does not protrude from the outer surface.

10. The battery cell according to any one of claims 7 to 9, wherein: The cover plate is entirely accommodated in the recess, and the cover plate has a third outer surface on a side away from the connecting portion. In the thickness direction, the third outer surface is closer to the connecting portion than the outer surface.

11. The battery cell according to any one of claims 1 to 10, wherein: The recess has an opening, the outer surface surrounds the opening, and an area of the outer surface is larger than an area of the opening.

12. The battery cell according to claim 11, wherein: An area of the opening is greater than or equal to 0.01 times an area of the outer surface and less than or equal to 0.34 times an area of the outer surface.

13. The battery cell according to claim 11 or 12, wherein: An area of a bottom surface of the recessed portion is greater than or equal to 0.01 times an area of the outer surface and less than or equal to 0.34 times an area of the outer surface.

14. The battery cell according to any one of claims 1 to 13, wherein: An area of a cross section of the recessed portion perpendicular to the thickness direction gradually decreases in a direction away from the outer surface.

15. The battery cell according to any one of claims 1 to 14, wherein: The housing comprises a shell and an end cover, the shell having a shell opening, and the end cover covers the shell opening; The housing includes an integrally formed side wall and an end wall, wherein the side wall surrounds the outer side of the electrode assembly, and the end wall is disposed opposite to the housing opening; The wall portion is the end cover or the end wall. 16 . The battery cell according to claim 1 , further comprising a current collecting member connecting the tab and the connecting portion.

17. A battery comprising: The battery cell according to any one of claims 1 to 16; as well as The confluence component contacts and is connected to the outer surface.

18. The battery according to claim 17, wherein The electrode terminal is welded to the busbar member to form a first weld portion, and the first weld portion and the recessed portion do not overlap each other when projected in a thickness direction of the wall portion.

19. The battery according to claim 18, wherein The wall portion is provided with an electrode lead-out hole, and the electrode lead-out hole passes through the wall portion along the thickness direction; The electrode terminal further includes a terminal body and a first limiting portion, the outer surface of the electrode terminal includes a first outer surface of the terminal body and a second outer surface of the first limiting portion, the recess is recessed from the first outer surface toward the electrode assembly, the terminal body is at least partially accommodated in the electrode lead-out hole, the first limiting portion is located on a side of the wall portion facing away from the electrode assembly and is connected to the outer peripheral surface of the terminal body, and the connecting portion is connected to the terminal body; The busbar member contacts the first outer surface, and at least a portion of the first welding portion is formed on the terminal body.

20. The battery according to claim 19, wherein The current collecting component is further in contact with the second outer surface, and a portion of the first welding portion is formed on the first limiting portion.

21. The battery according to claim 20, wherein The first welding portion includes a first welding mark and a second welding mark, the first welding mark is formed on the terminal body and the busbar component, and the second welding mark is formed on the first limiting portion and the busbar component; In the thickness direction, the maximum dimension of the first weld mark is greater than the maximum dimension of the second weld mark.

22. The battery according to any one of claims 17 to 21, wherein The battery cell further includes a cover plate, the cover plate being received in the recess, the cover plate being welded to the electrode terminal to form a second welding portion; In the thickness direction, the conduit component does not overlap with the second welding portion; or, in the thickness direction, the conduit component partially overlaps with the second welding portion, and an avoidance recess is provided on the side of the conduit component facing the second welding portion, and the avoidance recess is used to avoid the second welding portion.

23. An electrical device comprising the battery according to any one of claims 17 to 22, wherein the battery is used to provide electrical energy.

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