Battery cell, battery and electric device

Abstract

The utility model provides a battery monomer, a battery and a power utilization device. A battery cell includes a housing, an electrode terminal, an electrode assembly, and a current collecting member. The electrode terminal is arranged on the shell. The electrode assembly is accommodated in the shell, and one end, facing the electrode terminal, of the electrode assembly is provided with a first tab. The current collecting component is contained in the shell and arranged on the side, facing the electrode terminal, of the first electrode lug, the current collecting component comprises a first current collecting part and a second current collecting part connected to the first current collecting part, the first current collecting part is welded to the electrode terminal, the second current collecting part is connected to the electrode lug, and the thickness of the first current collecting part is larger than that of the second current collecting part.

Description

Technical Field

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

[0002] Battery monomers are widely used in electronic devices, such as mobile phones, laptop computers, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes and electric tools, etc.

[0003] In the development of battery technology, how to improve the reliability of battery cells is a research direction in battery technology. Summary of the invention

[0004] The present application provides a battery cell, a battery, and an electrical device, which can improve the reliability of the battery cell.

[0005] In a first aspect, an embodiment of the present application provides a battery cell, which includes a housing, an electrode terminal, an electrode assembly, and a current collecting member. The electrode terminal is disposed in the housing. The electrode assembly is accommodated in the housing, and a first pole ear is provided at one end of the electrode assembly facing the electrode terminal. The current collecting member is accommodated in the housing and is arranged on a side of the first pole ear facing the electrode terminal, the current collecting member includes a first current collecting portion and a second current collecting portion connected to the first current collecting portion, the first current collecting portion is welded to the electrode terminal, the second current collecting portion is connected to the pole ear, and the thickness of the first current collecting portion is greater than the thickness of the second current collecting portion.

[0006] The second current collecting part has a smaller thickness than the first current collecting part, and can be deformed to adapt to the morphology of the first pole ear, thereby reducing the gap between the second current collecting part and the first pole ear and improving the connection strength between the current collecting component and the first pole ear. The first current collecting part has a larger thickness than the second current collecting part. When welding the first current collecting part to the electrode terminal, the first current collecting part is not easily melted through, thereby reducing the risk of poor welding and improving the connection strength between the first current collecting part and the electrode terminal. The use of a first current collecting part with a larger thickness can improve the current flow capacity between the current collecting component and the electrode terminal.

[0007] In some embodiments, the second current collecting portion is disposed around the first current collecting portion, which can increase the connection area between the second current collecting portion and the first electrode tab, thereby improving the current flow capacity.

[0008] In some embodiments, the first current collecting portion is welded to the electrode terminal to form a first welding portion. In the thickness direction of the current collecting member, the size of the portion of the first welding portion formed on the first current collecting portion is smaller than the thickness of the first current collecting portion. When welding the current collecting member and the first current collecting portion, the first current collecting portion is not melted through, thereby improving the welding effect.

[0009] In some embodiments, in the thickness direction of the current collecting member, the size of the portion of the first welding portion formed on the first current collecting portion is greater than the thickness of the second current collecting portion. The first welding portion has a greater penetration in the thickness direction, thereby improving the connection strength and current flow capacity between the current collecting member and the electrode terminal.

[0010] In some embodiments, the Brinell hardness of the second current collecting part is higher than that of the first current collecting part. The second current collecting part has a higher hardness than the first current collecting part, and the risk of damage and deformation of the second current collecting part is lower during the production and transportation of the current collecting component.

[0011] In some embodiments, the thickness of the first current collecting part is 1.2-3 times the thickness of the second current collecting part to improve the connection strength and current carrying capacity between the first current collecting part and the electrode terminal, and reduce the loss of energy density of the battery cell caused by thickening the first current collecting part.

[0012] In some embodiments, at least a portion of the first current collecting portion protrudes from a surface of the second current collecting portion facing the electrode terminal and abuts against the electrode terminal. The first current collecting portion protrudes from the second current collecting portion toward the electrode terminal to reduce the risk of the second current collecting portion contacting the electrode terminal, thereby avoiding, to a certain extent, the second current collecting portion interfering with the contact between the first current collecting portion and the electrode terminal.

[0013] In some embodiments, the second current collecting portion is spaced apart from the electrode terminal in a thickness direction of the current collecting member, thereby reducing a risk that the second current collecting portion interferes with contact between the first current collecting portion and the electrode terminal.

[0014] In some embodiments, a first recess is provided on the side of the electrode terminal facing the current collecting member, and at least a portion of the first current collecting member is accommodated in the first recess and abuts against the bottom surface of the first recess. The first recess can accommodate at least a portion of the first current collecting member, thereby reducing the space occupied by the electrode terminal and the current collecting member in the thickness direction, improving space utilization, and improving the energy density of the battery cell. When assembling the electrode terminal and the current collecting member, the first recess can also position the first current collecting member, thereby reducing the difficulty of assembly and improving assembly efficiency.

[0015] In some embodiments, in the thickness direction of the current collecting member, the height of the first current collecting portion protruding from the surface of the second current collecting portion facing the electrode terminal is 1.2-2 times the depth of the first recess. By limiting the ratio of height to depth to be greater than or equal to 1.2, a gap can be retained between the second current collecting portion and the electrode terminal to reduce over-positioning. By limiting the ratio of height to depth to be less than or equal to 2, space waste can be reduced and space utilization can be improved.

[0016] In some embodiments, in the radial direction of the current collecting member, a gap is provided between the first current collecting portion and the side surface of the first recess. In the radial direction of the current collecting member, the first current collecting portion and the first recess are gap-matched, thereby reducing the difficulty of inserting the first current collecting portion into the first recess and reducing metal particles generated by friction between the first current collecting portion and the electrode terminal.

[0017] In some embodiments, a second recess is provided on a side of the electrode terminal away from the current collecting member, the electrode terminal includes a connecting portion located at the bottom of the second recess, the connecting portion is welded to the first current collecting portion to form a first welding portion, and the first welding portion is exposed to the second recess. By providing the second recess on the electrode terminal, the thickness of the connecting portion can be reduced, thereby reducing the welding power required for welding the connecting portion to the first current collecting portion, reducing heat generation, reducing the risk of other components being burned, and improving the reliability of the battery cell.

[0018] In some embodiments, a first recess is provided on one side of the electrode terminal facing the current collecting member, and a connection portion is formed between the bottom surface of the first recess and the bottom surface of the second recess. At least part of the first current collecting portion is accommodated in the first recess. The first recess can accommodate at least part of the first current collecting portion, thereby reducing the space occupied by the electrode terminal and the current collecting member in the thickness direction and providing space utilization. By providing the first recess and the second recess on both sides of the electrode terminal, the thickness of the connection portion can be reduced, and the welding power required for welding the welding connection portion to the first current collecting portion can be reduced.

[0019] In some embodiments, the first current collecting portion has a top surface that abuts against the bottom surface of the first recess. In the thickness direction of the current collecting member, the bottom surface of the second recess at least partially overlaps with the top surface, and the projection of the outer periphery of the bottom surface of the second recess is located within the projection of the top surface. When the battery cell is discharged, the current is transmitted outward through the connecting portion and the side wall of the second recess; the first welding portion is arranged close to the outer periphery of the bottom surface of the second recess, which can reduce the distance between the first welding portion and the side wall of the second recess, thereby shortening the conductive path and improving the current carrying capacity. The projection of the outer periphery of the bottom surface of the second recess is located within the projection of the top surface. When welding is performed close to the outer periphery of the bottom surface of the second recess, the risk of the molten pool extending outside the top surface can be reduced, the cold weld can be reduced, and the welding strength can be improved.

[0020] In some embodiments, the diameter of the top surface is greater than the diameter of the bottom surface of the second recess. The diameter difference between the bottom surface and the top surface of the first recess is less than the diameter difference between the top surface and the bottom surface of the second recess. The first collector can be loosely matched with the first recess, and the diameter difference between the bottom surface and the top surface of the first recess is related to the radial position of the first collector; by setting the diameter relationship between the top surface, the bottom surface of the first recess, and the bottom surface of the second recess, the outer periphery of the bottom surface of the second recess can be made not to exceed the outer periphery of the top surface, thereby reducing the risk of cold welding.

[0021] In some embodiments, the thickness of the connecting portion is 1-3 times the thickness of the first current collecting portion. By limiting the thickness ratio of the connecting portion to the thickness of the first current collecting portion to be greater than or equal to 1, the penetration depth of the first weld can be increased, and the connection strength and current carrying capacity between the connecting portion and the first current collecting portion can be improved. By limiting the thickness ratio of the connecting portion to the thickness of the first current collecting portion to be less than or equal to 3, the welding power required for welding the connecting portion to the first current collecting portion can be reduced, heat generation can be reduced, the risk of other components being burned can be reduced, and the reliability of the battery cell can be improved.

[0022] In some embodiments, the connection portion is provided with a first through hole, the first current collecting portion is provided with a second through hole, and the first through hole and the second through hole are arranged oppositely along the thickness direction of the current collecting member. The battery cell further includes a first seal, at least part of which is arranged in the second recess and used to seal the first through hole.

[0023] The first through hole and the second through hole can realize the communication between the inner space of the shell and the outer space of the shell during the production process of the battery cell; for example, the first through hole and the second through hole can be used to inject electrolyte, and can also be used to exhaust gas during the formation process. The first seal can be used to seal the first through hole to reduce the risk of external impurities entering the shell through the first through hole and the second through hole, thereby improving the reliability of the battery cell. The second recess can accommodate at least part of the first seal, thereby improving space utilization.

[0024] In some embodiments, in the radial direction of the current collecting component, the hole wall of the first through hole protrudes inwardly from the hole wall of the second through hole. The first seal includes a first sealing portion, a second sealing portion and a third sealing portion, the first sealing portion is located on the outside of the connecting portion, the second sealing portion is located on the inside of the connecting portion and is at least partially accommodated in the second through hole, and the third sealing portion is accommodated in the first through hole and connects the first sealing portion and the second sealing portion. In the thickness direction of the current collecting component, a part of the connecting portion is located between the first sealing portion and the second sealing portion. The connecting portion can limit the third sealing portion in the radial direction of the first through hole, and also limit the first sealing portion and the second sealing portion in the thickness direction, thereby achieving the fixation of the first seal and reducing the risk of the first seal falling from the connecting portion. The second through hole is larger than the first through hole in the radial direction, thereby providing space for the second sealing portion, so as to facilitate the overlap of the second sealing portion and the connecting portion in the thickness direction.

[0025] In some embodiments, in the radial direction of the current collecting member, the second sealing portion is spaced apart from the hole wall of the second through hole. When assembling the first sealing member, the embodiment of the present application can reduce the risk of the first sealing member squeezing the first current collecting portion and reduce the deformation of the current collecting member.

[0026] In some embodiments, the surface of the first current collecting portion facing the first pole lug abuts against the first pole lug, and the surface of the second current collecting portion facing the first pole lug abuts against the first pole lug. The first current collecting portion and the second current collecting portion abut against the first pole lug, which can increase the contact area between the current collecting component and the first pole lug and improve the flow area between the current collecting component and the first pole lug.

[0027] In some embodiments, the surface of the first current collecting portion facing the first pole lug is flush with the surface of the second current collecting portion facing the first pole lug, which can improve the uniformity of force on the first pole lug, reduce stress concentration, and reduce the risk of local collapse of the first pole lug.

[0028] In some embodiments, the first current collecting portion protrudes from the surface of the second current collecting portion facing the first pole lug. A pole lug groove is provided on the surface of the first pole lug facing the current collecting member, and a portion of the first current collecting portion is accommodated in the pole lug groove. The first current collecting portion is protruded toward the first pole lug to increase the thickness of the first current collecting portion; and by providing the pole lug groove, space can be provided for the first current collecting portion, thereby reducing the additional space occupied by the first current collecting portion and improving space utilization.

[0029] In some embodiments, the current collecting member includes a convex portion and a third concave portion, the second current collecting portion surrounds the convex portion, the convex portion protrudes from a surface of the second current collecting portion facing the electrode terminal, and the third concave portion corresponds to the convex portion and is recessed relative to a surface of the second current collecting portion facing the first electrode tab. The bottom wall of the third concave portion is the first current collecting portion.

[0030] By providing the convex part and the third concave part, the overall strength of the current collecting component can be increased, and the deformation of the current collecting component during production and transportation can be reduced. By providing the third concave part, the first current collecting part can be separated from the first pole ear, reducing the heat conducted to the first pole ear during the welding process of the first current collecting part and the electrode terminal, reducing the risk of thermal deformation and shrinkage of the separator of the electrode assembly, and improving the reliability of the battery cell.

[0031] In some embodiments, the current collecting member includes a convex portion and a third concave portion, the second current collecting portion surrounds the convex portion, the convex portion protrudes from the surface of the second current collecting portion facing the electrode terminal, and the third concave portion corresponds to the position of the convex portion and is recessed relative to the surface of the second current collecting portion facing the first electrode tab. The current collecting member also includes a current collecting plate accommodated in the third concave portion, the current collecting plate is fixed to the bottom wall of the third concave portion; the first current collecting portion includes the current collecting plate and the bottom wall of the third concave portion.

[0032] When welding the electrode terminal and the bottom wall of the third recess, the current collector can play a protective role. Even if the bottom wall of the third recess is melted through, the current collector can stop the molten metal and be used for welding, thereby reducing the risk of the molten metal falling. The current collector and the bottom wall of the third recess are formed independently, which can reduce the difficulty of forming the third recess and the convex part. Accommodating the current collector in the third recess can also improve space utilization.

[0033] In some embodiments, the housing includes a shell and an end cap, the shell has an opening, and the end cap covers the opening. The shell includes an end wall opposite to the end cap, and the electrode terminal is disposed on the end wall.

[0034] In some embodiments, the first pole ear is wound, a portion of the first pole ear is bent to form an overlapping area that overlaps in the axial direction of the electrode assembly, and the overlapping area is welded to the second current collector. The overlapping area of ​​the first pole ear has a multilayer structure, and welding the overlapping area to the second current collector can reduce the risk of cold welding and increase the welding area between the first pole ear and the second current collector to improve the current capacity. The second current collector is relatively thin, and it can adapt to the overlapping area by deformation, thereby reducing the gap between the second current collector and the first pole ear and reducing the risk of cold welding.

[0035] In a second aspect, an embodiment of the present application provides a battery, comprising a plurality of battery cells provided by any embodiment of the first aspect.

[0036] In a third aspect, an embodiment of the present application provides an electrical device, comprising a battery provided by any embodiment of the second aspect, and the battery is used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without paying creative work.

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

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

[0040] Figure 3 for Figure 2 A schematic diagram of the structure of the battery module shown;

[0041] Figure 4 A schematic diagram of the structure of a battery cell provided in some embodiments of the present application;

[0042] Figure 5 for Figure 4 An exploded schematic diagram of a battery cell is shown;

[0043] Figure 6 for Figure 4 A schematic cross-sectional view of a battery cell is shown;

[0044] Figure 7 for Figure 6 An enlarged schematic diagram at the circle frame;

[0045] Figure 8 for Figure 7 An enlarged schematic diagram at box A;

[0046] Fig. 9 A schematic cross-sectional view of an electrode terminal of a battery cell provided in some embodiments of the present application;

[0047] Fig.10 A schematic cross-sectional view of a current collecting component of a battery cell provided in some embodiments of the present application;

[0048] Fig.11 A partial cross-sectional schematic diagram of a battery cell provided in some other embodiments of the present application;

[0049] Fig.12 A partial cross-sectional schematic diagram of a battery cell provided in some other embodiments of the present application;

[0050] Fig.13 A partial cross-sectional schematic diagram of a battery cell provided in some further embodiments of the present application;

[0051] Fig.14 Schematic diagram of an electrode assembly and a current collecting member of a battery cell before assembly provided in some further embodiments of the present application.

[0052] The following are the descriptions of the reference numerals:

[0053] 1. Vehicle; 2. Battery; 3. Controller; 4. Motor; 5. Box; 5a. First box portion; 5b. Second box portion; 5c. Accommodation space; 6. Battery module; 7. Battery cell;

[0054] 10. electrode assembly; 11. main body; 12. first pole ear; 121. pole ear groove; 122. overlapping area; 13. second pole ear;

[0055] 20. housing; 21. shell; 211. end wall; 212. side wall; 22. end cover;

[0056] 30. Electrode terminal; 31. First recessed portion; 311. Bottom surface of the first recessed portion; 312. Side surface of the first recessed portion; 32. Second recessed portion; 321. Bottom surface of the second recessed portion; 33. Connecting portion; 331. First through hole;

[0057] 40. current collecting member; 41. first current collecting portion; 411. top surface; 412. second through hole; 42. second current collecting portion; 43. convex portion; 44. third concave portion; 45. side portion; 46. current collecting plate;

[0058] 50, first sealing member; 51, first sealing portion; 52, second sealing portion; 53, third sealing portion;

[0059] 60. Second sealing member;

[0060] W, first welding portion; Z, thickness direction. DETAILED DESCRIPTION

[0061] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0062] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. 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 and secondary relationship.

[0063] Reference to "embodiment" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0064] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0065] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0066] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0067] The term "plurality" used in the present application refers to two or more (including two).

[0068] 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.

[0069] The battery cells can be lithium-ion battery cells, sodium-ion battery cells, sodium-lithium-ion battery cells, lithium metal battery cells, sodium metal battery cells, lithium-sulfur battery cells, magnesium-ion battery cells, nickel-hydrogen battery cells, nickel-cadmium battery cells, lead-acid battery cells, etc., which are not limited in the embodiments of the present application.

[0070] A battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode and a negative electrode. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are inserted and removed back and forth between the positive electrode and the negative electrode.

[0071] In some embodiments, the electrode assembly includes a separator disposed between the positive electrode and the negative electrode. The separator can prevent the positive and negative electrodes from short-circuiting while allowing active ions to pass through.

[0072] In some embodiments, the positive electrode may be a positive electrode sheet, and the positive electrode sheet 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.

[0073] 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 disposed on either or both of the two facing surfaces of the positive electrode current collector.

[0074] 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, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc., treated with silver surface, may be used. The composite current collector may include a polymer material base 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.).

[0075] 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 positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium-containing phosphates may include, but are not limited to, lithium iron phosphate (such as LiFePO 4 (also referred to as LFP), composite materials of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), 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 LiCoO 2 ), lithium nickel oxide (such as LiNiO 2 ), lithium manganese oxide (such as LiMnO 2 、LiMn2O 4 ), 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 O 2 (Also referred to as NCM 333 )、LiNi 0.5 Co 0.2 Mn 0.3 O 2 (Also referred to as NCM 523 )、LiNi 0.5 Co 0.25 Mn 0.25 O 2 (Also referred to as NCM 211 )、LiNi 0.6 Co 0.2 Mn 0.2 O 2 (Also referred to as NCM 622 )、LiNi 0.8 Co 0.1 Mn 0.1 O 2 (Also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.80 Co 0.15 Al 0.05 O 2 ) and at least one of its modified compounds.

[0076] In some embodiments, the positive electrode may be a foamed metal or a foamed carbon. The foamed metal may be a foamed nickel, a foamed copper, a foamed aluminum, a foamed alloy, etc. When the foamed metal is used as the positive electrode, the positive electrode active material may not be provided on the surface of the foamed metal, but of course, the positive electrode active material may also be provided. As an example, a lithium source material, potassium metal or sodium metal may also be filled or / and deposited in the foamed metal, and the lithium source material is lithium metal and / or a lithium-rich material.

[0077] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0078] As an example, the negative electrode current collector can be a metal foil, a foamed metal, a foamed carbon or a composite current collector. For example, as a metal foil, aluminum or stainless steel treated with silver, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. can be used. The foamed metal can be a foamed nickel, a foamed copper, a foamed aluminum, a foamed alloy, etc. The composite current collector can include a polymer material base and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0079] 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.

[0080] 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 disposed on either or both of the two facing surfaces of the negative electrode current collector.

[0081] As an example, the negative electrode active material may adopt the negative electrode active material for battery cells 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.

[0082] 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.

[0083] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0084] In some embodiments, the separator is a separator. The present application has no particular limitation on the type of separator, and any known separator with a porous structure having good chemical stability and mechanical stability can be selected.

[0085] As an example, the main 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, without special restrictions. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without special restrictions. The separator can be a separate component located between the positive and negative electrodes, or it can be attached to the surface of the positive and negative electrodes.

[0086] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transmit ions and isolate the positive and negative electrodes.

[0087] In some embodiments, the battery cell further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The present application has no specific restrictions on the type of electrolyte, which can be selected according to needs. The electrolyte can be liquid, gel or solid.

[0088] The liquid electrolyte includes an electrolyte salt and a solvent.

[0089] In some embodiments, the electrolyte salt can 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.

[0090] 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, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent can also be selected from ether solvents. 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.

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

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

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

[0094] 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.

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

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

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

[0098] As an example, a plurality of positive electrode sheets and a plurality of negative electrode sheets may be provided respectively, and the plurality of positive electrode sheets and the plurality of negative electrode sheets may be alternately stacked.

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

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

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

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

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

[0104] In some embodiments, the electrode assembly is provided with tabs, which can lead current out of the electrode assembly. The tabs include a positive tab and a negative tab.

[0105] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel housing, an aluminum housing, a plastic housing (such as polypropylene), a composite metal housing (such as a copper-aluminum composite housing), or an aluminum-plastic film.

[0106] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell of other shapes. The prismatic battery cell includes a square shell battery cell, a blade-shaped battery cell, a polygonal battery, such as a hexagonal battery, etc. There is no special limitation in this application.

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

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

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

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

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

[0112] In some embodiments, the battery cell is further provided with an electrode terminal of the housing, and the electrode terminal is used to be electrically connected to the electrode tab of the electrode assembly to realize the charge and discharge of the electrode assembly. In order to facilitate assembly and improve the current carrying capacity of the battery cell, the battery cell is usually connected to the electrode tab and the electrode terminal of the electrode assembly through a current collecting member.

[0113] The current collecting member usually has a small thickness, so when the current collecting member and the tab are assembled, the current collecting member is easy to deform to adapt to the shape of the tab, thereby reducing the gap between the current collecting member and the tab and improving the connection strength between the current collecting member and the tab. When welding the current collecting member and the electrode terminal, the current collecting member may be melted through due to its small thickness, resulting in poor welding; in addition, the use of a small thickness current collecting member will also affect the current flow capacity between the current collecting member and the electrode terminal.

[0114] In view of this, an embodiment of the present application provides a technical solution, which increases the local thickness of the current collecting component to reduce the risk of the current collecting component being welded through when welding with the electrode terminal, thereby improving the current flow capacity between the current collecting component and the electrode terminal.

[0115] The battery cells described in the embodiments of the present application are suitable for use in batteries and electrical devices using the batteries.

[0116] The battery cells and batteries 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 be, but are not limited to, mobile phones, tablets, laptops, electric toys, electric tools, battery cars, electric cars, ships, spacecraft, etc. Among them, electric toys can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0117] For the convenience of description, the following embodiments are described by taking the electric device as a vehicle as an example.

[0118] Figure 1 A schematic diagram of the structure of a vehicle provided for some embodiments of the present application.

[0119] like Figure 1 As shown, a battery 2 is disposed inside the vehicle 1, and the battery 2 may be disposed 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 be used as an operating power source for the vehicle 1.

[0120] The vehicle 1 may further include a controller 3 and a motor 4 , wherein 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 starting, navigating, and driving the vehicle 1 .

[0121] In some embodiments of the present application, the battery 2 can not only serve as an operating power source for the vehicle 1, but also serve as a driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0122] Figure 2 Schematic diagram of an explosion of a battery provided in some embodiments of the present application. Figure 2 As shown, the battery 2 includes a box 5 and a battery cell ( Figure 2 The battery cells are contained in the box body 5.

[0123] The box 5 is used to accommodate the battery cells, and the box 5 can be of various structures. In some embodiments, the box 5 can include a first box portion 5a and a second box portion 5b, the first box portion 5a and the second box portion 5b cover each other, and the first box portion 5a and the second box portion 5b jointly define a storage space 5c for accommodating the battery cells. The second box portion 5b can be a hollow structure with one end open, the first box portion 5a is a plate-like structure, and the first box portion 5a covers the open side of the second box portion 5b to form a box 5 with a storage space 5c; the first box portion 5a and the second box portion 5b can also be hollow structures with one side open, and the open side of the first box portion 5a covers the open side of the second box portion 5b to form a box 5 with a storage space 5c. Of course, the first box portion 5a and the second box portion 5b can be of various shapes, such as a cylinder, a cuboid, etc.

[0124] In order to improve the sealing performance after the first box body part 5a and the second box body part 5b are connected, a sealing member, such as a sealant, a sealing ring, etc., may also be provided between the first box body part 5a and the second box body part 5b.

[0125] 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.

[0126] In the battery 2, there can be one or more battery cells. If there are multiple battery cells, the multiple battery cells can be connected in series, in parallel, or in mixed connection. Mixed connection means that the multiple battery cells are both connected in series and in parallel. The multiple battery cells can be directly connected in series, in parallel, or in mixed connection, and then the whole formed by the multiple battery cells is accommodated in the box 5; of course, multiple battery cells can also be connected in series, in parallel, or in mixed connection to form a battery module 6, and the multiple battery modules 6 are then connected in series, in parallel, or in mixed connection to form a whole, and accommodated in the box 5.

[0127] A battery cell may be the smallest unit constituting a battery.

[0128] Figure 3 for Figure 2 Schematic diagram of the structure of the battery module shown.

[0129] In some embodiments, Figure 3 As shown, there are multiple battery cells 7, and the multiple battery cells 7 are first connected in series, in parallel, or in mixed connection to form a battery module 6. The multiple battery modules 6 are then connected in series, in parallel, or in mixed connection to form a whole, and are accommodated in a box.

[0130] The multiple battery cells 7 in the battery module 6 can be electrically connected through a busbar component to achieve parallel connection, series connection or mixed connection of the multiple battery cells 7 in the battery module 6. There can be one or more busbar components, each of which is used to electrically connect at least two battery cells.

[0131] Figure 4 A schematic diagram of the structure of a battery cell provided in some embodiments of the present application; Figure 5 for Figure 4 An exploded schematic diagram of a battery cell is shown; Figure 6 for Figure 4 A schematic cross-sectional view of a battery cell is shown; Figure 7 for Figure 6 An enlarged schematic diagram at the circle frame; Figure 8 for Figure 7 An enlarged schematic diagram at box A; Fig. 9 A schematic cross-sectional view of an electrode terminal of a battery cell provided in some embodiments of the present application; Fig.10 A schematic cross-sectional view of a current collecting component of a battery cell provided in some embodiments of the present application.

[0132] Reference Figures 4 to 10 An embodiment of the present application provides a battery cell 7 , which includes a housing 20 and an electrode assembly 10 , at least a portion of the electrode assembly 10 is accommodated in the housing 20 .

[0133] The housing 20 is a hollow structure, and a space for accommodating the electrode assembly 10 and the electrolyte is formed therein. The shape of the housing 20 can be determined according to the specific shape of the electrode assembly 10. For example, if the electrode assembly 10 is a rectangular parallelepiped structure, a rectangular housing can be selected; if the electrode assembly 10 is a cylindrical structure, a cylindrical housing can be selected.

[0134] As an example, the housing 20 includes a shell 21 and an end cover 22 . The shell 21 has an opening, and the end cover 22 is used to cover the opening.

[0135] 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.

[0136] The housing 21 and the end cover 22 may be independent components. For example, an opening may be provided on the housing 21, and the end cover 22 may cover the opening to form an internal cavity of the battery cell 7.

[0137] The shell 21 can be in various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism shape, etc. Specifically, the shape of the shell 21 can be determined according to the specific shape and size of the electrode assembly 10. The shell 21 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc., and the embodiment of the present application does not impose any special restrictions on this.

[0138] The shape of the end cap 22 can be adapted to the shape of the housing 21 to match 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.), so that the end cap 22 is not easily deformed when squeezed and collided, so that the battery cell 7 can have a higher structural strength and the reliability performance can also be improved.

[0139] The end cover 22 is connected to the housing 21 by welding, bonding, clamping or other methods.

[0140] The housing 21 may be open at one end or at both ends. In some examples, the housing 21 may be a structure with an opening at one end, and an end cap 22 is provided and covers the housing 21. In other examples, the housing 21 may be a structure with openings at both ends, and two end caps 22 are provided, and the two end caps 22 cover the two openings of the housing 21 respectively.

[0141] The electrode assembly 10 is a component where electrochemical reactions occur in the battery cell 7. One or more electrode assemblies 10 may be contained in the housing 21.

[0142] In some embodiments, the electrode assembly 10 includes a main body 11, a first electrode tab 12, and a second electrode tab 13. One of the first electrode tab 12 and the second electrode tab 13 is a positive electrode tab, and the other is a negative electrode tab.

[0143] As an example, the electrode assembly 10 includes a positive electrode sheet and a negative electrode sheet. The parts of the positive electrode sheet and the negative electrode sheet with active materials constitute the main body 11 of the electrode assembly 10, the part of the positive electrode sheet without active materials constitutes the positive electrode ear, and the part of the negative electrode sheet without active materials constitutes the negative electrode ear. The positive electrode ear and the negative electrode ear can be located at one end of the main body 11 or at both ends of the main body 11.

[0144] During the charge and discharge process of the battery, the positive electrode active material and the negative electrode active material react with the electrolyte.

[0145] In some embodiments, the battery cell 7 includes an electrode terminal 30 disposed on the housing 20. The electrode terminal 30 can be used as an output electrode of the battery cell 7, which is used to connect to an external circuit. The electrode terminal 30 is used to connect to a busbar component to achieve electrical connection between the battery cells 7.

[0146] The electrode terminal 30 may be disposed on the housing 21 or on the end cover 22 .

[0147] The number of electrode terminals 30 may be one or more.

[0148] In some examples, there is one electrode terminal 30, which is electrically connected to the first pole tab 12; optionally, at least a portion of the housing 20 may be electrically connected to the second pole tab 13. The electrode terminal 30 and the housing 20 may serve as two output poles of the battery cell 7, respectively.

[0149] In some other examples, there are two electrode terminals 30, and the two electrode terminals 30 are electrically connected to the first electrode tab 12 and the second electrode tab 13 respectively. The two electrode terminals 30 can serve as two output poles of the battery cell 7 respectively.

[0150] The electrode terminal 30 may be insulated and disposed on the housing 21 , or may be electrically connected to the housing 21 , as long as the first electrode tab 12 and the second electrode tab 13 are prevented from being electrically connected.

[0151] In some embodiments, the battery cell 7 further includes a current collecting member 40 that electrically connects the first electrode tab 12 to the electrode terminal 30 .

[0152] In some embodiments, the battery cell 7 includes a housing 20, an electrode terminal 30, an electrode assembly 10, and a current collecting member 40. The electrode terminal 30 is disposed in the housing 20. The electrode assembly 10 is accommodated in the housing 20, and a first pole tab 12 is provided at one end of the electrode assembly 10 facing the electrode terminal 30. The current collecting member 40 is accommodated in the housing 20 and is disposed on the side of the first pole tab 12 facing the electrode terminal 30, and the current collecting member 40 includes a first current collecting portion 41 and a second current collecting portion 42 connected to the first current collecting portion 41, the first current collecting portion 41 is welded to the electrode terminal 30, the second current collecting portion 42 is connected to the pole tab, and the thickness of the first current collecting portion 41 is greater than the thickness of the second current collecting portion 42.

[0153] The second current collecting portion 42 may be connected to the first electrode tab 12 by welding, abutting, bonding or other methods, so as to achieve electrical connection between the current collecting member 40 and the first electrode tab 12 .

[0154] The arrangement of the first current collecting part 41 and the second current collecting part 42 can be flexibly set as needed. In some examples, the second current collecting part 42 is arranged around the first current collecting part 41; in other examples, the first current collecting part 41 is arranged around the second current collecting part 42; in still other examples, there are multiple second current collecting parts 42, and the multiple second current collecting parts 42 are arranged at intervals along the circumference of the first current collecting part 41 and connected to the outer periphery of the first current collecting part 41.

[0155] The first current collecting portion 41 and the second current collecting portion 42 may be formed integrally, or may be formed independently and connected by welding or other means.

[0156] The Brinell hardness of the second current collecting portion 42 may be higher than, equal to, or lower than the Brinell hardness of the first current collecting portion 41 .

[0157] The ratio of the thickness of the first current collecting section 41 to the thickness of the second current collecting section 42 is greater than 1. Exemplarily, the ratio of the thickness of the first current collecting section 41 to the thickness of the second current collecting section 42 is 1.1, 1.2, 1.5, 2, 2.5, 3, 3.5, 4 or 5.

[0158] The second current collecting portion 42 may or may not be in contact with the electrode terminal 30. The first current collecting portion 41 may or may not be in contact with the first electrode tab 12.

[0159] In the embodiment of the present application, the second current collecting portion 42 has a smaller thickness than the first current collecting portion 41, and can be deformed to adapt to the morphology of the first pole tab 12, thereby reducing the gap between the second current collecting portion 42 and the first pole tab 12, and improving the connection strength between the current collecting member 40 and the first pole tab 12. The first current collecting portion 41 has a larger thickness than the second current collecting portion 42, and when welding the first current collecting portion 41 and the electrode terminal 30, the first current collecting portion 41 is not easily melted through, thereby reducing the risk of poor welding and improving the connection strength between the first current collecting portion 41 and the electrode terminal 30. The use of the first current collecting portion 41 with a larger thickness can improve the flow capacity between the current collecting member 40 and the electrode terminal 30.

[0160] Compared with the solution of thickening the current collecting member 40 as a whole, the embodiment of the present application can also reduce the space and weight occupied by the current collecting member 40 and improve the energy density of the battery cell 7.

[0161] In some embodiments, when assembling the electrode terminal 30 and the current collecting member 40 , the electrode terminal 30 and the current collecting member 40 are welded from the electrode terminal side.

[0162] For example, laser may be irradiated on the electrode terminal 30 to achieve welding between the electrode terminal 30 and the first current collecting portion 41 .

[0163] In some embodiments, the first current collecting portion 41 does not overlap the second current collecting portion 42 in the thickness direction Z of the current collecting member 40. The thickness of the first current collecting portion 41 and the thickness of the second current collecting portion 42 do not overlap in the thickness direction Z, thereby reducing the maximum dimension of the current collecting member 40 in the thickness direction Z.

[0164] In some embodiments, the first electrode tab 12 and the second current collecting portion 42 are welded.

[0165] Exemplarily, the first pole tab 12 and the second current collecting portion 42 are laser welded. When welding the first pole tab 12 and the second current collecting portion 42, the laser may be irradiated on the second current collecting portion 42, and a portion of the second current collecting portion 42 is fused with a portion of the first pole tab 12. The second current collecting portion 42 needs to be melted through by the laser, and the second current collecting portion 42 with a smaller thickness is easy to melt through, thereby reducing the demand for welding power.

[0166] In some embodiments, at least a portion of the first current collecting portion 41 overlaps the electrode terminal 30 in the thickness direction Z of the current collecting member 40 .

[0167] In some embodiments, the housing 21 includes an end wall 211 opposite to the end cover 22 , and the electrode terminal 30 is disposed on the end wall 211 .

[0168] In some embodiments, the projection of the first collecting portion 41 along the thickness direction Z is a circle, a square, a triangle, a polygon or other shapes.

[0169] In some embodiments, the end wall 211 is electrically connected to the second pole ear 13, and the electrode terminal 30 is insulated and disposed on the end wall 211. The end wall 211 and the electrode terminal 30 can serve as two output poles of the battery cell 7; the end wall 211 and the electrode terminal 30 are located on the same side of the electrode assembly 10, which facilitates the current collection component to connect multiple battery cells 7 into groups.

[0170] In some embodiments, the housing 21 further includes a side wall 212 , which surrounds the electrode assembly 10 and is formed integrally with the end wall 211 . The side wall 212 is connected to the end cover 22 .

[0171] In some embodiments, the battery cell 7 is a cylindrical battery cell, and the side wall 212 is a cylindrical structure; alternatively, the battery cell 7 is a square battery cell, and the side wall 212 is a square cylinder structure.

[0172] In some embodiments, the second electrode tab 13 is electrically connected to the end wall 211 through the side wall 212. Optionally, the side wall 212 is electrically connected to the end cover 22, and the second electrode tab 13 is electrically connected to the end wall 211 through the end cover 22 and the side wall 212.

[0173] In some embodiments, the second current collecting portion 42 is disposed around the first current collecting portion 41 , which can increase the connection area between the second current collecting portion 42 and the first electrode tab 12 , thereby improving the current flow capacity.

[0174] The first current collecting portion 41 has a relatively large thickness and is located in the middle of the current collecting member 40 , which can improve the overall rigidity of the current collecting member 40 and reduce deformation of the current collecting member 40 during production or transportation.

[0175] In some embodiments, the first current collecting portion 41 is welded to the electrode terminal 30 and forms a first welding portion W.

[0176] The number of the first welding part W may be one or more.

[0177] The first welding portion W may be a spot welding mark or a linear welding mark. The first welding portion W may be a straight welding mark or a curved welding mark.

[0178] In some embodiments, the second current collecting portion 42 is welded to the first electrode tab 12 to form a second welding portion (not shown).

[0179] In some embodiments, in the thickness direction Z of the current collecting member 40 , a size h of a portion of the first welding portion W formed on the first current collecting portion 41 is ≤ 1. 1 Less than the thickness t of the first collector 41 1 .

[0180] When the current collecting member 40 and the first current collecting portion 41 are welded, the first current collecting portion 41 is not melted through, thereby improving the welding effect.

[0181] In some embodiments, in the thickness direction Z of the current collecting member 40, the first welding portion W is spaced from the surface of the first current collecting portion 41 facing the first electrode tab 12. Exemplarily, in the thickness direction Z of the current collecting member 40, the spacing between the first welding portion W and the surface of the first current collecting portion 41 facing the first electrode tab 12 is t 1 -h 1 .

[0182] During the welding process of the electrode terminal 30 and the first current collecting portion 41 , the molten metal is unlikely to drop onto the electrode assembly 10 , thereby reducing the risk of the electrode assembly 10 being burned and improving the reliability of the battery cell 7 .

[0183] In some embodiments, in the thickness direction Z of the current collecting member 40 , a size h of a portion of the first welding portion W formed on the first current collecting portion 41 is ≤ 1. 1 Greater than the thickness t of the second header 42 2 .

[0184] The first welding portion W has a greater penetration in the thickness direction Z, thereby improving the connection strength and current passing capacity between the current collecting member 40 and the electrode terminal 30 .

[0185] In some embodiments, the Brinell hardness of the second current collecting part 42 is higher than the Brinell hardness of the first current collecting part 41. During the production and transportation of the current collecting component 40, the current collecting component 40 may be damaged or deformed due to the compression of other structures. In the embodiment of the present application, although the second current collecting part 42 is thinner than the first current collecting part 41, the second current collecting part 42 has a higher hardness than the first current collecting part 41, which can reduce the risk of damage and deformation of the second current collecting part 42.

[0186] The thickness t of the first header 41 1 is the thickness t of the second header 42 2 Optionally, t 1 / t 2is 1.2, 1.3, 1.5, 1.6, 1.8, 2.0, 2.1, 2.3, 2.5, 2.7, 2.9 or 3.

[0187] The present application embodiment will 1 / t 2 is limited to be greater than or equal to 1.2 to reduce the risk of the first current collecting portion 41 being melted through during welding and to improve the connection strength and current carrying capacity between the first current collecting portion 41 and the electrode terminal 30. 1 / t 2 It is limited to be less than or equal to 3, so as to reduce the space and weight occupied by the first current collecting part 41 and reduce the loss of energy density of the battery cell 7 caused by thickening the first current collecting part 41 .

[0188] In some embodiments, t 1 It is 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.7mm or 0.8mm.

[0189] In some embodiments, t 2 It is 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm or 0.4mm.

[0190] In some embodiments, at least a portion of the first current collecting portion 41 protrudes from a surface of the second current collecting portion 42 facing the electrode terminal 30 and abuts against the electrode terminal 30 .

[0191] The first current collecting part 41 protrudes from the second current collecting part 42 toward the electrode terminal 30 to reduce the risk of the second current collecting part 42 contacting the electrode terminal 30 , thereby avoiding the second current collecting part 42 interfering with the contact between the first current collecting part 41 and the electrode terminal 30 to a certain extent.

[0192] In some embodiments, the second current collecting portion 42 is spaced apart from the electrode terminal 30 in the thickness direction Z of the current collecting member 40 , thereby reducing the risk of the second current collecting portion 42 interfering with the contact between the first current collecting portion 41 and the electrode terminal 30 .

[0193] In some embodiments, in the thickness direction Z, the gap between the second current collecting portion 42 and the electrode terminal 30 is greater than or equal to 0.2t 2 .

[0194] In some embodiments, a first recess 31 is disposed on one side of the electrode terminal 30 facing the current collecting member 40 , and at least a portion of the first current collecting portion 41 is received in the first recess 31 and abuts against a bottom surface 311 of the first recess.

[0195] The depth of the first recess 31 is h 2. For example, h 2 It may be the maximum dimension of the first recess 31 along the thickness direction Z of the current collecting member 40 .

[0196] In the thickness direction Z of the current collecting member 40 , the height of the first current collecting portion 41 protruding from the surface of the second current collecting portion 42 facing the electrode terminal 30 is h. 3 . For example, h 3 Greater than or equal to h 2 .

[0197] For example, in the radial direction of the current collecting component 40 , the first recessed portion 31 and the first current collecting portion 41 may be an interference fit, a clearance fit, or a transition fit.

[0198] The first recess 31 can accommodate at least part of the first current collecting part 41, thereby reducing the space occupied by the electrode terminal 30 and the current collecting member 40 in the thickness direction Z, improving space utilization, and increasing the energy density of the battery cell 7. When assembling the electrode terminal 30 and the current collecting member 40, the first recess 31 can also position the first current collecting part 41, thereby reducing assembly difficulty and improving assembly efficiency.

[0199] In some embodiments, in the thickness direction Z of the current collecting member 40 , the first current collecting portion 41 protrudes from the surface of the second current collecting portion 42 facing the electrode terminal 30 by a height h 3 is the depth h of the first recess 31 2 1.2-2 times of.

[0200] Optionally, h 3 / h 2 is 1.2, 1.3, 1.5, 1.6, 1.8 or 2.

[0201] h 3 / h 2 By limiting h to be greater than or equal to 1.2, a gap can be maintained between the second current collecting portion 42 and the electrode terminal 30 to reduce over-positioning. 3 / h 2 Limiting it to less than or equal to 2 can reduce space waste and improve space utilization.

[0202] In some embodiments, in the radial direction of the current collecting member 40 , a gap is provided between the first current collecting portion 41 and the side surface 312 of the first recess.

[0203] In the radial direction of the current collecting member 40 , the first current collecting portion 41 is loosely matched with the first recess 31 , thereby reducing the difficulty of inserting the first current collecting portion 41 into the first recess 31 and reducing metal particles generated by friction between the first current collecting portion 41 and the electrode terminal 30 .

[0204] In some embodiments, a second recess 32 is provided on the side of the electrode terminal 30 away from the current collecting member 40 , and the electrode terminal 30 includes a connecting portion 33 located at the bottom of the second recess 32 , the connecting portion 33 is welded to the first current collecting portion 41 and forms a first welding portion W, and the first welding portion W is exposed to the second recess 32 .

[0205] The second recess 32 may be a cylindrical recess, a conical recess, a stepped recess, or a recess of other shapes.

[0206] The connecting portion 33 corresponds to at least a portion of the bottom surface 321 of the second recess. The bottom surface 321 of the second recess may be a plane or a curved surface. Optionally, the bottom surface 321 of the second recess is a plane perpendicular to the thickness direction Z.

[0207] During welding, laser is irradiated on the connection part 33 from the outside; a part of the connection part 33 and a part of the first collector 41 melt to form a molten pool, and the molten pool solidifies to form a first welded part W. The first welded part W has a welded surface exposed to the second recessed part 32, and the welded surface is uneven compared to the bottom surface 321 of the second recessed part.

[0208] By opening the second recess 32 on the electrode terminal 30 , the thickness of the connecting portion 33 can be reduced, thereby reducing the welding power required for welding the connecting portion 33 to the first current collecting portion 41 , reducing heat generation, reducing the risk of other components being burned, and improving the reliability of the battery cell 7 .

[0209] In some embodiments, the first recess 31 is provided on the side of the electrode terminal 30 facing the current collecting member 40, and the second recess 32 is provided on the side of the electrode terminal 30 facing away from the current collecting member 40, and a connection portion 33 is formed between the bottom surface 311 of the first recess and the bottom surface 321 of the second recess. At least a portion of the first current collecting portion 41 is accommodated in the first recess 31.

[0210] Exemplarily, the bottom surface 311 of the first recess at least partially overlaps the bottom surface 321 of the second recess in the thickness direction Z. The area where the bottom surface 311 of the first recess overlaps the bottom surface 321 of the second recess in the thickness direction Z defines a connecting portion 33 .

[0211] The bottom surface 311 of the first recess may be larger than, equal to, or smaller than the bottom surface 321 of the second recess.

[0212] The first recess 31 can accommodate at least part of the first current collecting portion 41, thereby reducing the space occupied by the electrode terminal 30 and the current collecting member 40 in the thickness direction Z, and improving space utilization. By providing the first recess 31 and the second recess 32 on both sides of the electrode terminal 30, the thickness of the connection portion 33 can be reduced, and the welding power required for welding the welding connection portion 33 to the first current collecting portion 41 can be reduced.

[0213] In some embodiments, the first current collecting portion 41 has a top surface 411 that abuts against the bottom surface 311 of the first recess. In the thickness direction Z of the current collecting member 40, the bottom surface 321 of the second recess at least partially overlaps with the top surface 411, and the projection of the outer periphery of the bottom surface 321 of the second recess is located within the projection of the top surface 411.

[0214] The top surface 411 of the first current collecting portion 41 may be circular, annular, polygonal or other shapes. The bottom surface 311 of the first recess may be circular, annular, polygonal or other shapes.

[0215] When the battery cell 7 is discharged, the current is transmitted outward through the connecting portion 33 and the side wall of the second recess 32; the first welding portion W is arranged close to the outer periphery of the bottom surface 321 of the second recess, which can reduce the distance between the first welding portion W and the side wall of the second recess 32, thereby shortening the conductive path and improving the current carrying capacity. The projection of the outer periphery of the bottom surface 321 of the second recess is located within the projection of the top surface 411. When welding is performed near the outer periphery of the bottom surface 321 of the second recess, the risk of the molten pool extending outside the top surface 411 can be reduced, thereby reducing the number of cold welds and improving the welding strength.

[0216] In some embodiments, in the radial direction of the current collecting member 40, the outer periphery of the top surface 411 exceeds the outer periphery of the bottom surface 321 of the second recess. The portion of the top surface 411 that radially exceeds the bottom surface 321 of the second recess can be used as a redundant design to reduce the risk of cold welding caused by assembly errors.

[0217] In some embodiments, the diameter of the top surface 411 is greater than the diameter of the bottom surface 321 of the second recess. The diameter difference between the bottom surface 311 and the top surface 411 of the first recess is smaller than the diameter difference between the top surface 411 and the bottom surface 321 of the second recess.

[0218] Exemplarily, the top surface 411 may be annular or circular. If the top surface 411 is annular, the diameter of the top surface 411 is the outer diameter of the top surface 411 .

[0219] Exemplarily, the bottom surface 321 of the second recessed portion may be annular or circular. If the bottom surface 321 of the second recessed portion is annular, the diameter of the top surface 411 is the outer diameter of the top surface 411 .

[0220] Exemplarily, the bottom surface 311 of the first recess may be annular or circular. If the bottom surface 311 of the first recess is annular, the diameter of the top surface 411 is the outer diameter of the top surface 411 .

[0221] The diameter of the bottom surface 311 of the first recess is greater than or equal to the diameter of the top surface 411 .

[0222] The first collecting portion 41 can be loosely fitted with the first recess 31, and the diameter difference between the bottom surface 311 and the top surface 411 of the first recess is related to the radial position of the first collecting portion 41; the present application sets the diameter relationship between the top surface 411, the bottom surface 311 of the first recess and the bottom surface 321 of the second recess, so that the outer periphery of the bottom surface 321 of the second recess does not exceed the outer periphery of the top surface 411, thereby reducing the risk of cold welding.

[0223] In some embodiments, the top surface 411 may also be a curved surface, for example, the top surface 411 is an arc surface.

[0224] In some embodiments, the thickness t of the connecting portion 33 is 3 is the thickness t of the first header 41 1 1-3 times of.

[0225] Optionally, t 3 / t 1 is 1, 1.5, 2, 2.5, or 3.

[0226] t 3 / t 1 Limiting t to be greater than or equal to 1 can increase the penetration depth of the first welding portion W and improve the connection strength and flow capacity between the connecting portion 33 and the first current collecting portion 41. 3 / t 1 It is limited to be less than or equal to 3, so as to reduce the welding power required for welding the connection portion 33 and the first current collecting portion 41 , reduce heat generation, reduce the risk of other components being burned, and improve the reliability of the battery cell 7 .

[0227] In some embodiments, the connection portion 33 is provided with a first through hole 331 , the first current collecting portion 41 is provided with a second through hole 412 , and the first through hole 331 and the second through hole 412 are disposed opposite to each other along the thickness direction Z of the current collecting member 40 .

[0228] In the thickness direction Z of the current collecting member 40 , the first through-hole 331 and the second through-hole 412 at least partially overlap.

[0229] The aperture of the first through hole 331 may be greater than, less than, or equal to the aperture of the second through hole 412 .

[0230] Exemplarily, the first through hole 331 extends from the bottom surface 321 of the second recess to the bottom surface 311 of the first recess. The bottom surface 311 of the first recess is an annular surface where the first through hole 331 is disposed, and the bottom surface 321 of the second recess is an annular surface where the first through hole 331 is disposed.

[0231] In some embodiments, the first through hole 331 and the second through hole 412 may be used to inject electrolyte into the housing 20 .

[0232] In some embodiments, the battery cell 7 further includes a first seal 50 , at least a portion of which is disposed in the second recess 32 and is used to seal the first through hole 331 .

[0233] The first through hole 331 and the second through hole 412 can realize the communication between the inner space of the housing 20 and the outer space of the housing 20 during the production process of the battery cell 7; for example, the first through hole 331 and the second through hole 412 can be used to inject electrolyte, and can also be used to exhaust gas during the formation process. The first seal 50 can be used to seal the first through hole 331 to reduce the risk of external impurities entering the interior of the housing 20 through the first through hole 331 and the second through hole 412, thereby improving the reliability of the battery cell 7. The second recess 32 can accommodate at least part of the first seal 50, thereby improving space utilization.

[0234] In some embodiments, in the radial direction of the current collecting member 40 , the hole wall of the first through hole 331 protrudes inwardly from the hole wall of the second through hole 412 .

[0235] Exemplarily, the diameter of the first through hole 331 is smaller than the diameter of the second through hole 412 .

[0236] In some embodiments, the first sealing member 50 includes a first sealing portion 51, a second sealing portion 52, and a third sealing portion 53, wherein the first sealing portion 51 is located outside the connecting portion 33, the second sealing portion 52 is located inside the connecting portion 33 and is at least partially accommodated in the second through hole 412, and the third sealing portion 53 is accommodated in the first through hole 331 and connects the first sealing portion 51 and the second sealing portion 52. In the thickness direction Z of the current collecting member 40, a portion of the connecting portion 33 is located between the first sealing portion 51 and the second sealing portion 52.

[0237] The connecting portion 33 can limit the third sealing portion 53 in the radial direction of the first through hole 331, and also limit the first sealing portion 51 and the second sealing portion 52 in the thickness direction Z, thereby fixing the first sealing member 50 and reducing the risk of the first sealing member 50 falling from the connecting portion 33. The second through hole 412 is larger than the first through hole 331 in the radial direction, thereby providing space for the second sealing portion 52, and facilitating the overlap of the second sealing portion 52 and the connecting portion 33 in the thickness direction Z.

[0238] As an example, the second sealing portion 52 may or may not be in contact with the hole wall of the second through hole 412 .

[0239] In some embodiments, the first sealing portion 51 contacts the bottom surface 321 of the second recess. The second sealing portion 52 contacts the bottom surface 311 of the first recess.

[0240] In some embodiments, the second sealing portion 52 does not overlap with the first current collecting portion 41 in the thickness direction Z. The embodiment of the present application can reduce the size of the first sealing member 50 in the thickness direction Z.

[0241] In some embodiments, in the radial direction of the current collecting member 40 , the second sealing portion 52 is spaced apart from the hole wall of the second through hole 412 .

[0242] The embodiment of the present application can reduce the risk of the first sealing member 50 squeezing the first current collecting portion 41 and reduce the deformation of the current collecting member 40 when the first sealing member 50 is assembled.

[0243] In some embodiments, the third sealing portion 53 is interference fit with the first through hole 331 .

[0244] In some embodiments, the first sealing member 50 is made of an elastic material, for example, rubber.

[0245] In some embodiments, the first welding portion W does not overlap with the first sealing portion 51 in the thickness direction Z. The embodiment of the present application can reduce the risk of the first welding portion W crushing the first sealing portion 51 .

[0246] In some embodiments, the first welding portion W surrounds the first sealing portion 51 .

[0247] In some embodiments, the first seal 50 is configured to be installed on the connection portion 33 before welding the connection portion 33 and the first current collecting portion 41. During welding, the first seal 50 can seal the first through hole 331, reduce the risk of metal particles generated by welding falling into the electrode assembly 10 through the first through hole 331, and improve reliability.

[0248] In some embodiments, the diameter D of the second through hole 412 is equal to the thickness t of the second header 42. 2 1 to 10 times of D / t 2 Limiting D / t to be greater than or equal to 1 can improve the electrolyte injection efficiency and reduce the deformation of the current collecting member 40 during the electrolyte injection process. 2 By limiting the ratio to be greater than or equal to 10, the loss of the flow area of ​​the current collecting member 40 can be reduced.

[0249] In some embodiments, the battery cell 7 further includes a second sealant 60 , which is located outside the first welding portion W, connected to the electrode terminal 30 and used to seal the second recess 32 .

[0250] The second sealing member 60 can protect the first welding portion W from the outside, thereby reducing the risk of the first welding portion W being corroded.

[0251] In some embodiments, at least a portion of the second sealing member 60 is accommodated in the second recess 32 , thereby improving space utilization and reducing the maximum size of the battery cell 7 .

[0252] In some embodiments, the second sealing member 60 is fixed to the sidewall of the second recess 32 .

[0253] In some embodiments, the second sealing member 60 is welded to the sidewall of the second recess 32 .

[0254] In some embodiments, a sidewall of the second recess 32 is provided with a step surface, and the second sealing member 60 abuts against the step surface. The step surface can support the second sealing member 60 .

[0255] In some embodiments, in the thickness direction Z of the current collecting member 40 , the first seal 50 and the second seal 60 are spaced apart from each other.

[0256] In some embodiments, the electrode terminal 30 is used to be directly connected to the busbar, for example, the electrode terminal 30 is used to be welded to the busbar. Alternatively, the second seal 60 is a conductive member, and the electrode terminal 30 is connected to the busbar through the second seal 60, and the second seal 60 can be used to be welded to the busbar.

[0257] In some embodiments, a surface of the first current collecting portion 41 facing the first electrode tab 12 abuts against the first electrode tab 12 , and a surface of the second current collecting portion 42 facing the first electrode tab 12 abuts against the first electrode tab 12 .

[0258] The first current collecting portion 41 and the second current collecting portion 42 are both against the first electrode tab 12 , which can increase the contact area between the current collecting component 40 and the first electrode tab 12 and improve the flow area between the current collecting component 40 and the first electrode tab 12 .

[0259] In some embodiments, the surface of the first current collecting portion 41 facing the first pole tab 12 is flush with the surface of the second current collecting portion 42 facing the first pole tab 12 , which can improve the uniformity of force on the first pole tab 12 , reduce stress concentration, and reduce the risk of local collapse of the first pole tab 12 .

[0260] In some embodiments, the current collecting member 40 is made by pressing a metal plate, the thinned portion of the metal plate is the second current collecting portion 42 , and the unpressed portion of the current collecting member 40 is the first current collecting portion 41 .

[0261] Fig.11 A partial cross-sectional schematic diagram of a battery cell provided in some other embodiments of the present application.

[0262] Reference Fig.11In some embodiments, the first current collecting portion 41 protrudes from the surface of the second current collecting portion 42 facing the first pole tab 12. The surface of the first pole tab 12 facing the current collecting member 40 is provided with a pole tab groove 121, and a part of the first current collecting portion 41 is accommodated in the pole tab groove 121.

[0263] The first current collecting part 41 is protruded toward the first pole lug 12 to increase the thickness of the first current collecting part 41 ; and the pole lug groove 121 is provided to provide space for the first current collecting part 41 , thereby reducing the additional space occupied by the first current collecting part 41 and improving space utilization.

[0264] In some embodiments, when the current collecting member 40 and the electrode assembly 10 are assembled, the first current collecting portion 41 presses the first electrode tab 12 and forms the electrode tab groove 121. The embodiment of the present application can increase the pressure between the first current collecting portion 41 and the first electrode tab 12, improve the stability of the contact between the first current collecting portion 41 and the first electrode tab 12, and reduce the resistance.

[0265] In some embodiments, the first current collecting portion 41 protrudes from both the surface of the second current collecting portion 42 facing the first electrode tab 12 and the surface of the second current collecting portion 42 facing away from the first electrode tab 12 .

[0266] In the thickness direction Z of the current collecting member 40 , the first current collecting portion 41 protrudes from both sides of the second current collecting portion 42 at the same time, and the thickness of the first current collecting portion 41 can be further increased.

[0267] In some other alternative embodiments, the surface of the first current collecting portion 41 facing away from the first electrode tab 12 may also be flush with the surface of the second current collecting portion 42 facing away from the first electrode tab 12 .

[0268] Fig.12 A partial cross-sectional schematic diagram of a battery cell provided in some other embodiments of the present application.

[0269] like Fig.12 As shown, in some embodiments, the current collecting member 40 includes a convex portion 43 and a third concave portion 44, the second current collecting portion 42 surrounds the convex portion 43, the convex portion 43 protrudes from the surface of the second current collecting portion 42 facing the electrode terminal 30, and the third concave portion 44 corresponds to the convex portion 43 and is recessed relative to the surface of the second current collecting portion 42 facing the first electrode tab 12. The bottom wall of the third concave portion 44 is the first current collecting portion 41.

[0270] By providing the convex portion 43 and the third concave portion 44, the overall strength of the current collecting member 40 can be increased, and the deformation of the current collecting member 40 during production and transportation can be reduced. By providing the third concave portion 44, the first current collecting portion 41 can be separated from the first pole tab 12, reducing the heat conducted to the first pole tab 12 during the welding process of the first current collecting portion 41 and the electrode terminal 30, reducing the risk of thermal deformation and shrinkage of the separator of the electrode assembly 10, and improving the reliability of the battery cell 7.

[0271] In some embodiments, the protrusion 43 and the third recess 44 are formed by a stamping process.

[0272] In some embodiments, the protrusion 43 includes a side portion 45 disposed around the first current collecting portion 41 , and the side portion 45 connects the first current collecting portion 41 and the second current collecting portion 42 . The side portion 45 and the first current collecting portion 41 define a third recess 44 .

[0273] Fig.13 A partial cross-sectional schematic diagram of a battery cell provided in some further embodiments of the present application.

[0274] Reference Fig.13 The current collecting member 40 includes a convex portion 43 and a third concave portion 44. The second current collecting portion 42 surrounds the convex portion 43. The convex portion 43 protrudes from the surface of the second current collecting portion 42 facing the electrode terminal 30. The third concave portion 44 corresponds to the convex portion 43 and is recessed relative to the surface of the second current collecting portion 42 facing the first electrode tab 12. The current collecting member 40 also includes a current collecting plate 46 accommodated in the third concave portion 44, and the current collecting plate 46 is fixed to the bottom wall of the third concave portion 44. The first current collecting portion 41 includes the current collecting plate 46 and the bottom wall of the third concave portion 44.

[0275] The current collecting plate 46 may be connected to the bottom wall of the third recess 44 by bonding, welding, clamping or other processes.

[0276] The thickness of the bottom wall of the third recess 44 may be greater than, equal to, or less than the thickness of the second header 42 .

[0277] When welding the electrode terminal 30 and the bottom wall of the third recess 44, the current collecting plate 46 can play a protective role. Even if the bottom wall of the third recess 44 is melted through, the current collecting plate 46 can stop the molten metal and be used for welding, thereby reducing the risk of the molten metal falling. The current collecting plate 46 and the bottom wall of the third recess 44 are formed independently, which can reduce the difficulty of forming the third recess 44 and the convex part 43. Accommodating the current collecting plate 46 in the third recess 44 can also improve space utilization.

[0278] In some embodiments, a portion of the first welding portion W is formed on the current collecting plate 46. During welding, a portion of the current collecting plate 46, a portion of the connecting portion 33, and a portion of the bottom wall of the third recess 44 melt to form a molten pool, which solidifies to form the first welding portion W.

[0279] Fig.14 Schematic diagram of an electrode assembly and a current collecting member of a battery cell before assembly provided in some further embodiments of the present application.

[0280] Reference Fig.14 In some embodiments, the first electrode tab 12 is wound, a portion of the first electrode tab 12 is bent to form an overlapping region 122 that overlaps in the axial direction of the electrode assembly 10 , and the overlapping region 122 is welded to the second current collecting portion 42 .

[0281] Optionally, the axial direction is parallel to the thickness direction Z.

[0282] The overlapping region 122 of the first pole tab 12 has a multi-layer structure. Welding the overlapping region 122 to the second current collecting portion 42 can reduce the risk of cold welding and increase the welding area between the first pole tab 12 and the second current collecting portion 42, thereby improving the current carrying capacity. The second current collecting portion 42 has a small thickness and can adapt to the overlapping region 122 by deformation, thereby reducing the gap between the second current collecting portion 42 and the first pole tab 12 and reducing the risk of cold welding.

[0283] Exemplarily, the first electrode tab 12 is bent through a flattening process or a smoothing process to form an overlapping area 122 .

[0284] In the axial direction, the number of overlapping layers of the first pole tab 12 in the overlapping region 122 is greater than or equal to 2. Optionally, the number of overlapping layers of the first pole tab 12 in the overlapping region 122 is greater than or equal to 5.

[0285] In some embodiments, a portion of the first electrode tab 12 is bent inward in the radial direction of the electrode assembly 10 .

[0286] 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.

[0287] According to some embodiments of the present application, the present application further provides an electric device, including a battery cell 7 of any of the above embodiments, the battery cell 7 is used to provide electric energy for the electric device. The electric device can be any of the above-mentioned devices or systems using the battery cell 7.

[0288] Reference Figures 5 to 10 The embodiment of the present application provides a battery cell 7 , which includes a housing 20 , an electrode assembly 10 , an electrode terminal 30 and a current collecting member 40 .

[0289] The housing 20 includes a shell 21 and an end cap 22. The shell 21 has an opening, and the end cap 22 is used to cover the opening. The shell 21 includes an end wall 211 opposite to the end cap 22, and the electrode terminal 30 is insulated and disposed on the end wall 211. At least part of the electrode assembly 10 is accommodated in the shell 21.

[0290] The electrode assembly 10 includes a main body 11, a first pole tab 12 and a second pole tab 13. The first pole tab 12 extends from one end of the main body 11 facing the electrode terminal 30, and the second pole tab 13 extends from one end of the main body 11 away from the electrode terminal 30. The first pole tab 12 and the second pole tab 13 have opposite polarities, the first pole tab 12 is electrically connected to the electrode terminal 30, and the second pole tab 13 is electrically connected to the end wall 211.

[0291] The current collecting member 40 is accommodated in the housing 20 and is disposed on the side of the first electrode tab 12 facing the electrode terminal 30. The current collecting member 40 includes a first current collecting portion 41 and a second current collecting portion 42 surrounding the first current collecting portion 41. The first current collecting portion 41 is welded to the electrode terminal 30 to form a first welding portion W, and the second current collecting portion 42 is welded to the electrode tab to form a second welding portion. The thickness of the first current collecting portion 41 is greater than the thickness of the second current collecting portion 42.

[0292] The electrode terminal 30 has a first recess 31 on one side facing the current collecting member 40 , and a second recess 32 on the other side facing away from the current collecting member 40 . A connection portion 33 is formed between the bottom surface 311 of the first recess and the bottom surface 321 of the second recess.

[0293] A portion of the first current collecting portion 41 protrudes from the surface of the second current collecting portion 42 facing the electrode terminal 30. At least a portion of the first current collecting portion 41 is accommodated in the first recess 31 and abuts against the bottom surface 311 of the first recess. The connecting portion 33 is welded to the first current collecting portion 41 and forms a first welding portion W. The first welding portion W is exposed to the second recess 32.

[0294] In the thickness direction Z of the current collecting member 40 , a dimension h of a portion of the first welding portion W formed on the first current collecting portion 41 is 1 Less than the thickness t of the first collector 41 1 , and is greater than the thickness t of the second header 42 2 .

[0295] The connecting portion 33 is provided with a first through hole 331, and the first current collecting portion 41 is provided with a second through hole 412, which are arranged opposite to each other along the thickness direction Z of the current collecting member 40. The battery cell 7 further includes a first sealing member 50, at least a portion of which is arranged in the second recess 32 and used to seal the first through hole 331.

[0296] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0297] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein, but these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery cell, characterized in that: include: shell; An electrode terminal, disposed on the housing; An electrode assembly is contained in the housing, and a first electrode tab is provided at one end of the electrode assembly facing the electrode terminal; A current collecting component is accommodated in the shell and is arranged on the side of the first electrode tab facing the electrode terminal, the current collecting component includes a first current collecting part and a second current collecting part connected to the first current collecting part, the first current collecting part is welded to the electrode terminal, the second current collecting part is connected to the electrode tab, and the thickness of the first current collecting part is greater than the thickness of the second current collecting part.

2. The battery cell according to claim 1, characterized in that: The second current collecting portion is disposed around the first current collecting portion.

3. The battery cell according to claim 1, characterized in that: The first current collecting portion is welded to the electrode terminal to form a first welding portion; In a thickness direction of the current collecting member, a size of a portion of the first welding portion formed on the first current collecting portion is smaller than a thickness of the first current collecting portion.

4. The battery cell according to claim 3, characterized in that: In a thickness direction of the current collecting member, a size of a portion of the first welding portion formed on the first current collecting portion is larger than a thickness of the second current collecting portion.

5. The battery cell according to claim 1, characterized in that: The Brinell hardness of the second current collecting portion is higher than the Brinell hardness of the first current collecting portion.

6. The battery cell according to claim 1, characterized in that: The thickness of the first current collecting portion is 1.2-3 times the thickness of the second current collecting portion.

7. The battery cell according to claim 1, characterized in that: At least a portion of the first current collecting portion protrudes from a surface of the second current collecting portion facing the electrode terminal and abuts against the electrode terminal.

8. The battery cell according to claim 1, characterized in that: The second current collecting portion is disposed spaced apart from the electrode terminal in a thickness direction of the current collecting member.

9. The battery cell according to claim 1, characterized in that: A first recess is formed on a side of the electrode terminal facing the current collecting member, and at least a portion of the first current collecting member is received in the first recess and abuts against a bottom surface of the first recess.

10. The battery cell according to claim 9, characterized in that: In the thickness direction of the current collecting member, a height of the first current collecting portion protruding from a surface of the second current collecting portion facing the electrode terminal is 1.2-2 times a depth of the first recess.

11. The battery cell according to claim 9, characterized in that: In the radial direction of the current collecting member, a gap is provided between the first current collecting portion and the side surface of the first recess.

12. The battery cell according to claim 1, characterized in that: The electrode terminal has a second recess on one side away from the current collecting member. The electrode terminal includes a connecting portion at the bottom of the second recess. The connecting portion is welded to the first current collecting portion to form a first welding portion. The first welding portion is exposed to the second recess.

13. The battery cell according to claim 12, characterized in that: A first recess is provided on a side of the electrode terminal facing the current collecting member, and the connecting portion is formed between a bottom surface of the first recess and a bottom surface of the second recess; At least a portion of the first current collecting portion is accommodated in the first recess.

14. The battery cell according to claim 13, characterized in that: The first current collecting portion has a top surface abutting against a bottom surface of the first recess; In the thickness direction of the current collecting member, the bottom surface of the second recess at least partially overlaps the top surface, and a projection of an outer periphery of the bottom surface of the second recess is located within a projection of the top surface.

15. The battery cell according to claim 14, characterized in that: The diameter of the top surface is greater than the diameter of the bottom surface of the second recess; A diameter difference between a bottom surface of the first recess and the top surface is smaller than a diameter difference between the top surface and a bottom surface of the second recess.

16. The battery cell according to claim 12, characterized in that: The thickness of the connecting portion is 1 to 3 times the thickness of the first current collecting portion.

17. The battery cell according to claim 12, characterized in that: The connecting portion is provided with a first through hole, the first current collecting portion is provided with a second through hole, and the first through hole and the second through hole are arranged opposite to each other along the thickness direction of the current collecting component; The battery cell further includes a first sealing member, at least a portion of which is disposed in the second recess and is used to seal the first through hole.

18. The battery cell according to claim 17, characterized in that: In the radial direction of the current collecting member, the hole wall of the first through hole protrudes inwardly from the hole wall of the second through hole; The first sealing member includes a first sealing portion, a second sealing portion and a third sealing portion, the first sealing portion is located on the outside of the connecting portion, the second sealing portion is located on the inside of the connecting portion and is at least partially accommodated in the second through hole, and the third sealing portion is accommodated in the first through hole and connects the first sealing portion and the second sealing portion; A portion of the connection portion is located between the first sealing portion and the second sealing portion in a thickness direction of the current collecting member.

19. The battery cell according to claim 18, characterized in that: In the radial direction of the current collecting member, the second sealing portion is spaced apart from a hole wall of the second through hole.

20. The battery cell according to claim 1, characterized in that A surface of the first current collecting portion facing the first pole tab abuts against the first pole tab, and a surface of the second current collecting portion facing the first pole tab abuts against the first pole tab.

21. The battery cell according to claim 20, characterized in that: A surface of the first current collecting portion facing the first electrode tab is flush with a surface of the second current collecting portion facing the first electrode tab.

22. The battery cell according to claim 20, characterized in that: The first current collecting portion protrudes from a surface of the second current collecting portion facing the first electrode tab; A tab groove is formed on a surface of the first tab facing the current collecting member, and a portion of the first current collecting portion is accommodated in the tab groove.

23. The battery cell according to claim 1, characterized in that: The current collecting member comprises a convex portion and a third concave portion, the second current collecting portion surrounds the convex portion, the convex portion protrudes from a surface of the second current collecting portion facing the electrode terminal, and the third concave portion corresponds to the convex portion and is concave relative to a surface of the second current collecting portion facing the first electrode tab; The bottom wall of the third recess serves as the first current collecting portion.

24. The battery cell according to claim 1, characterized in that The current collecting member comprises a convex portion and a third concave portion, the second current collecting portion surrounds the convex portion, the convex portion protrudes from a surface of the second current collecting portion facing the electrode terminal, and the third concave portion corresponds to the convex portion and is concave relative to a surface of the second current collecting portion facing the first electrode tab; The current collecting member further includes a current collecting plate received in the third recess, wherein the current collecting plate is fixed to a bottom wall of the third recess; and the first current collecting portion includes the current collecting plate and the bottom wall of the third recess.

25. The battery cell according to claim 1, characterized in that The housing comprises a shell and an end cover, the shell has an opening, and the end cover covers the opening; The housing includes an end wall opposite to the end cover, and the electrode terminal is disposed on the end wall.

26. The battery cell according to claim 1, characterized in that: The first electrode tab is wound, a portion of the first electrode tab is bent to form an overlapping region that overlaps in the axial direction of the electrode assembly, and the overlapping region is welded to the second current collecting portion.

27. A battery, characterized in that: The invention comprises a plurality of battery cells according to any one of claims 1 to 26.

28. An electrical device, characterized in that: A battery according to claim 27, for providing electrical energy.

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