Battery cell, battery and electric device

Abstract

Provided in the present application are a battery cell, a battery and an electric device. The battery cell comprises a housing and an electrode assembly, wherein the electrode assembly is disposed inside the housing, and comprises a main body portion, a positive electrode tab and a negative electrode tab; the positive electrode tab and the negative electrode tab are located on the same side of the main body portion in a first direction, the first direction being the axial direction of the battery cell; the dimension of at least a portion of the positive electrode tab in the first direction is greater than the dimension of at least a portion of the negative electrode tab in the first direction. In the embodiments of the present application, the height dimension of at least one of the positive electrode tab and the negative electrode tab in the first direction is adjusted. Specifically, the negative electrode tab can be further compressed so as to reduce the difference in corresponding compaction density between the positive electrode tab and the negative electrode tab, such that the corresponding welding yield of the positive electrode tab and the negative electrode tab is improved, thereby improving the fabrication reliability of the battery cell.

Description

Battery cell, battery and electric device Cross-reference to related applications

[0001] This application claims priority to Chinese Patent Application No. 202421519667.8, filed on June 28, 2024, entitled “Battery cell, battery and electric device”, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of batteries, and in particular to a battery cell, a battery and an electric device. BACKGROUND

[0003] Battery cells are widely used in electronic devices, such as mobile phones, notebook computers, electric vehicles, electric cars, electric planes, electric ships, electric toy cars, electric toy ships, electric toy planes, electric tools, and the like. Battery cells can include cadmium-nickel battery cells, hydrogen-nickel battery cells, lithium-ion battery cells, and secondary alkaline zinc-manganese battery cells, etc.

[0004] In the development of battery technology, how to improve the reliability of the battery has always been a research direction in battery technology. SUMMARY

[0005] In view of the above problems, the present application provides a battery cell, a battery and an electric device, which can improve the preparation yield of the battery cell.

[0006] In one aspect, the present application provides a battery cell, comprising a shell and an electrode assembly, the electrode assembly is arranged in the shell, the electrode assembly comprises a main body part, a positive electrode tab and a negative electrode tab, the positive electrode tab and the negative electrode tab are located on the same side of the main body part along a first direction, the first direction is the axial direction of the battery cell, and the size of the positive electrode tab in the first direction is greater than the size of the negative electrode tab in the first direction.

[0007] In the above scheme, the height dimension of at least one of the positive electrode tab and the negative electrode tab in the first direction is adjusted. Specifically, at least part of the positive electrode tab in the first direction can be further compressed so that the size of at least part of the positive electrode tab in the first direction is greater than the size of at least part of the negative electrode tab in the first direction, thereby reducing the difference in density corresponding to the positive electrode tab and the negative electrode tab, improving the welding yield of the positive electrode tab and the negative electrode tab, and improving the preparation reliability of the battery cell.

[0008] In some embodiments, the electrode assembly includes a plurality of first layer structures arranged in a stack along a second direction, and a plurality of second layer structures arranged in a stack along the second direction, the first layer structures are arranged spaced apart from the second layer structures, the plurality of first layer structures form a positive electrode tab, the plurality of second layer structures form a negative electrode tab, the first direction intersects the second direction, a thickness of the first layer structure is greater than a thickness of the second layer structure.

[0009] In the above solution, the negative electrode tab is further compressed, so that the height dimension of the negative electrode tab in the first direction is less than the height dimension of the positive electrode tab in the first direction, thereby increasing the corresponding density of the negative electrode tab, reducing the density difference between the positive electrode tab and the negative electrode tab, and helping to improve the welding yield and improve the preparation reliability of the battery monomer.

[0010] In some embodiments, the material of the positive electrode tab includes metal aluminum, and the material of the negative electrode tab includes metal copper.

[0011] In the above solution, by adjusting the height of the negative electrode tab in the first direction to be less than the height of the positive electrode tab in the first direction, the negative electrode tab can be further compressed relative to the positive electrode tab, thereby increasing the corresponding density of the negative electrode tab, reducing the risk of the isolation member being burned out at the corresponding welding position of the negative electrode tab during welding, and improving the preparation yield and reliability of the battery monomer.

[0012] In some embodiments, the size of the positive electrode tab in the first direction is H1, and the size of the negative electrode tab in the first direction is H2, H1 and H2 satisfy: 0.2mm≤H1-H2≤1.5mm.

[0013] In the above solution, the height relationship of the positive electrode tab and the negative electrode tab in the first direction is further limited, so that the height of the positive electrode tab beyond the negative electrode tab in the first direction is not less than 0.2mm and not more than 1.5mm, thereby ensuring that the density difference between the two can be controlled within a certain range, and thereby reducing the risk of the isolation member being burned or the welding being poor at the corresponding welding position of one of the positive electrode tab and the negative electrode tab, improving the welding reliability of the positive electrode tab and the negative electrode tab, and improving the preparation yield of the battery monomer.

[0014] In some embodiments, the density R1 of the positive electrode tab is 0.2g / cm3≤R1≤1g / cm3, and / or the density R2 of the negative electrode tab is 0.5g / cm3≤R2≤1.5g / cm3.

[0015] In the above scheme, by limiting the density range of at least one of the positive tab and the negative tab, the difference in density corresponding to the positive tab and the negative tab is reduced, the risk of burning the isolation piece due to the too low density of at least one of the positive tab and the negative tab is reduced, and the welding strength corresponding to at least one of the positive tab and the negative tab is improved, thereby improving the preparation yield of the battery monomer.

[0016] In some embodiments, the battery monomer further comprises a positive terminal and a negative terminal disposed on the shell and insulated from each other, the positive terminal being electrically connected to the positive tab, and the negative terminal being electrically connected to the negative tab.

[0017] In the above scheme, the positive tab and the negative tab are located at the same end of the main body part, and both can be welded and fixed by the same laser equipment. On this basis, by adjusting the size of the negative tab and the positive tab in the first direction, the density between the two is kept the same or similar, thereby improving the welding reliability of the positive tab and the negative tab, and improving the preparation yield of the battery monomer.

[0018] In some embodiments, the battery monomer further comprises a current collecting member, the current collecting member comprising a first connecting part connected to the positive tab and a second connecting part connected to the negative tab, the first connecting part and the second connecting part being insulated from each other. The first connecting part has a first surface facing the positive tab, and the second connecting part has a second surface facing the negative tab, and the first surface is located on the side of the second surface away from the main body part.

[0019] In the above scheme, since the size of the positive tab in the first direction is greater than the size of the negative tab in the first direction, in order to meet the connection requirements of the first connecting part and the second connecting part with the positive tab and the negative tab, the structure of at least one of the first connecting part and the second connecting part is adjusted, so that the first surface in the first connecting part is located on the side of the second surface in the second connecting part away from the main body. In this way, the first connecting part and the second connecting part are matched and connected with tabs of different heights respectively, and the connection requirements between the tabs and the current collecting member are met.

[0020] In some embodiments, the current collecting member further comprises an insulating part disposed between the first connecting part and the second connecting part, the first connecting part has a first connecting end connected to the insulating part, and the second connecting part has a second connecting end connected to the insulating part, and the first connecting end is located on the side of the second connecting end away from the main body part.

[0021] In the above scheme, the first connecting end is an end structure on the first connecting part for connecting to the insulating part, and the second connecting end is an end structure on the second connecting part for connecting to the insulating part. Further, in order to enable the first connecting part to contact the positive tab and the second connecting part to contact the negative tab, the first connecting end is arranged on the side of the second connecting end away from the main body part, that is, the end of the first connecting part connected to the insulating part is farther away from the main body part than the end of the second connecting part connected to the insulating part, so that the first surface is on the side of the second surface away from the main body part, meeting the contact needs of the first surface with the positive tab and the contact needs of the second surface with the negative tab.

[0022] In some embodiments, the first connecting part includes a first body part and a first protruding part protruding from the first body part towards the positive tab, and the protruding size of the first protruding part relative to the first body part is L1. The second connecting part includes a second body part and a second protruding part protruding from the second body part towards the negative tab, and the protruding size of the second protruding part relative to the second body part is L2, L2>L1.

[0023] In the above scheme, in order to enable the first protruding part to contact and connect with the positive tab and the second protruding part to contact and connect with the negative tab, the protruding sizes of the first protruding part and the second protruding part are limited, so that the protruding size L1 of the first protruding part relative to the first body part is smaller than the protruding size L2 of the second protruding part relative to the second body part, that is, the second protruding part protrudes closer to the body part than the first protruding part, so as to realize the contact connection between the first protruding part and the positive tab and the contact connection between the second protruding part and the negative tab, which has strong practicability.

[0024] In some embodiments, the battery cell is a cylindrical battery cell.

[0025] In the above scheme, considering that the cylindrical battery cell may have a problem of poor welding, the negative tab in the cylindrical battery cell is further compressed, so that the size of the positive tab in the first direction is greater than the size of the negative tab in the first direction, thereby reducing the difference in density between the positive tab and the negative tab, so as to improve the welding yield of the positive tab and the negative tab and improve the preparation reliability of the cylindrical battery cell.

[0026] In a second aspect, the embodiments of the present application provide a battery, which includes the battery cell in any of the preceding embodiments.

[0027] In a third aspect, the embodiments of the present application provide a power consumption device, which includes the battery cell in any of the preceding embodiments, and the battery cell is used to provide electric energy.

[0028] The above description is only a summary of the technical solutions of the present application. In order to make the technical means of the present application more clearly understood and implemented according to the content of the description, and in order to make the above and other purposes, characteristics and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0030] Fig. 1 is a structural schematic diagram of a vehicle provided by an embodiment of the present application;

[0031] Fig. 2 is an exploded structural schematic diagram of a battery provided by an embodiment of the present application;

[0032] Fig. 3 is an internal structural schematic diagram of a battery module provided by an embodiment of the present application;

[0033] Fig. 4 is an exploded structural schematic diagram of a battery cell provided by an embodiment of the present application;

[0034] Fig. 5 is a cross-sectional structural schematic diagram of a battery cell provided by an embodiment of the present application;

[0035] Fig. 6 is an enlarged structural schematic diagram of region Q in Fig. 5;

[0036] Fig. 7 is a structural schematic diagram of an electrode assembly before being flattened in another battery cell provided by an embodiment of the present application;

[0037] Fig. 8 is a structural schematic diagram of a current collecting member in another battery cell provided by an embodiment of the present application;

[0038] Fig. 9 is a structural schematic diagram of a current collecting member in another battery cell provided by an embodiment of the present application.

[0039]

[0040] In the drawings:

[0041] 1000, vehicle;

[0042] 100, battery; 200, controller; 300, motor; 400, box; 401, first box part; 402, second box part; 403, accommodating part; 500, battery cell; 600, battery module;

[0043] 10, housing;

[0044] 20, electrode assembly; 21, positive electrode tab; 22, negative electrode tab; 23, main body portion;

[0045] 31, positive electrode terminal; 32, negative electrode terminal;

[0046] 40, current collecting member; 41, first connecting portion; 411, first body portion; 412, first protruding portion; 42, second connecting portion; 421, second body portion; 422, second protruding portion; 43, insulating portion;

[0047] C1, first layer structure; C2, second layer structure;

[0048] D1, first connecting end; D2, second connecting end;

[0049] M1, first surface; M2, second surface;

[0050] X, first direction; Y, second direction. DETAILED DESCRIPTION

[0051] The embodiments of the present application will be described in detail with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical scheme of the present application, and therefore only serve as examples, and cannot be used to limit the protection scope of the present application.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the specification herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application; the terms "comprising" and "having," and any variations thereof, as used in the specification and claims herein, are intended to cover both the inclusive and exclusive aspects of the terms.

[0053] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0054] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearance of the phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily independent or alternative embodiments to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0055] In the description of the embodiments of the present application, the term "and / or" is merely an association relationship of associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A existing alone, A and B existing together, and B existing alone. In addition, the character " / " in this paper generally represents that the front and rear associated objects are in an "or" relationship.

[0056] In the description of the embodiments of the present application, the term "a plurality of" refers to two or more (including two), and similarly, "a plurality of groups" refers to two or more groups (including two groups), and "a plurality of pieces" refers to two or more pieces (including two pieces).

[0057] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0058] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0059] In the embodiments of the present application, the battery cell can be a secondary battery, which refers to a battery cell that can be activated by charging after discharging of the battery cell.

[0060] The battery cell can be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel hydrogen battery, a nickel cadmium battery, a lead-acid battery, etc. The embodiments of the present application are not limited thereto.

[0061] The battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of the battery cell, active ions (such as lithium ions) are inserted and extracted between the positive electrode and the negative electrode. The separator is arranged between the positive electrode and the negative electrode, which can prevent the positive and negative electrodes from short-circuiting to a certain extent, and at the same time allow the active ions to pass through.

[0062] In some embodiments, the positive electrode can be a positive electrode sheet, which can include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0063] As an example, the positive electrode current collector has two surfaces opposite in the thickness direction thereof, and the positive electrode active material is disposed on either one or both of the two opposite surfaces of the positive electrode current collector.

[0064] As an example, the positive electrode current collector can employ a metal foil or a composite current collector. For example, as a metal foil, silver surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium, etc. can be employed. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can 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 base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0065] As an example, the positive electrode active material can include at least one of lithium-containing phosphates, lithium transition metal oxides, and respective modified compounds thereof. However, the present application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials can also be used. These positive electrode active materials can be used alone only one or two or more thereof can be used in combination. Among them, examples of the lithium-containing phosphates can include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (which can also be referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon.

[0066] In some embodiments, the negative electrode can be a negative electrode sheet, which can include a negative electrode current collector.

[0067] As an example, the negative electrode current collector can employ a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, silver surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium, etc. can be employed. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. The composite current collector can include a polymer material base layer 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 base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0068] As an example, the negative electrode sheet can include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0069] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0070] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. 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, and lithium titanate, etc.

[0071] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0072] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0073] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0074] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride, and ceramic.

[0075] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0076] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel-like, or solid.

[0077] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0078] In some implementations, the electrode assembly is a stacked structure.

[0079] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0080] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0081] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0082] In some embodiments, the housing may be provided with functional components such as electrode terminals. The electrode terminals can be used to electrically connect to the electrode assembly for outputting or inputting electrical energy into the battery cell.

[0083] In some embodiments, a current collector may be provided inside the housing, and the electrode assembly may be electrically connected to the housing or electrode terminals provided on the housing through the current collector.

[0084] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. This application does not have any particular limitations.

[0085] The battery mentioned in the embodiments of this application refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity.

[0086] In some embodiments, the battery can be a battery module, and when there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0087] In some embodiments, the battery can be a battery pack, which includes a housing and individual battery cells, with the individual battery cells or battery modules housed within the housing.

[0088] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0089] In some embodiments, the battery can be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0090] As a crucial component of a battery cell, the electrode assembly typically uses tabs to electrically connect to the electrode terminals on the battery cell to enable charging and discharging. Before connecting to the electrode terminals, the tabs need to be flattened or smoothed to achieve a predetermined density sufficient for welding strength with the electrode terminals. However, due to differences in materials and single-layer thickness between the positive and negative electrode tabs, related technologies often flatten or smooth them to the same size and height. If one tab achieves the predetermined density, the other may not, leading to poor welding during the welding process with the electrode terminals and negatively impacting the reliability of the battery cell.

[0091] Based on the above-mentioned technical problems, this application provides a battery cell, a battery, and an electrical device. By adjusting the height dimension of at least one of the positive electrode tab and the negative electrode tab in a first direction, the density difference between the corresponding positive electrode tab and the negative electrode tab is reduced, thereby improving the welding yield of the corresponding positive electrode tab and the reliability of battery cell preparation.

[0092] The technical solutions described in this application are applicable to batteries and electrical devices that use batteries. Electrical devices include, for example, mobile phones, portable devices, laptops, electric vehicles, electric cars, ships, spacecraft, electric toys, and power tools. Spacecraft include, for example, airplanes, rockets, space shuttles, and spacecraft. Electric toys include, for example, stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. Power tools include, for example, metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as, electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers.

[0093] The battery cells described in this application are not limited to the electrical devices described above, but for the sake of brevity, the following embodiments are all illustrated using electric vehicles as an example.

[0094] Please refer to Figure 1, which is a simplified schematic diagram of a vehicle 1000 provided in an embodiment of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery 100 can be installed inside the vehicle 1000; specifically, for example, the battery 100 can be installed at the bottom, front, or rear of the vehicle 1000. The battery 100 can be used to power the vehicle 1000; for example, the battery 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200, for example, is used to control the battery to supply power to the motor 300. The battery can be used for starting the vehicle 1000, navigation, etc. Of course, the battery 100 can also be used to drive the vehicle 1000, replacing or partially replacing gasoline or natural gas to provide propulsion for the vehicle 1000.

[0095] Figure 2 is an exploded view of a battery provided in some embodiments of this application. As shown in Figure 2, the battery 100 includes a housing 400 and a battery cell (not shown in the figure), with the battery cell housed within the housing 400.

[0096] The housing 400 is used to accommodate individual battery cells, and the housing 400 can have various structures. In some embodiments, the housing 400 may include a first housing portion 401 and a second housing portion 402, which overlap each other, and together define a receiving portion 403 for accommodating the individual battery cells. The second housing portion 402 may be a hollow structure with one end open, and the first housing portion 401 may be a plate-like structure, with the first housing portion 401 covering the open side of the second housing portion 402 to form a housing with the receiving portion 403; alternatively, both the first housing portion 401 and the second housing portion 402 may be hollow structures with one side open, with the open side of the first housing portion 401 covering the open side of the second housing portion 402 to form a housing 400 with the receiving portion. Of course, the first housing portion 401 and the second housing portion 402 can have various shapes, such as cylinders, cuboids, etc.

[0097] In battery 100, there can be one or more battery cells. If there are multiple battery cells, they can be connected in series, parallel, or a combination thereof. A combination thereof means that multiple battery cells are connected in both series and parallel. Multiple battery cells can be directly connected in series, parallel, or a combination thereof, and then the whole assembly of multiple battery cells is housed in the housing 400. Alternatively, multiple battery cells can first be connected in series, parallel, or a combination thereof to form a battery module 600, and then multiple battery modules 600 can be connected in series, parallel, or a combination thereof to form a whole assembly, which is then housed in the housing 400.

[0098] Figure 3 is an exploded view of the battery module 600 shown in Figure 2. In some embodiments, as shown in Figure 3, there are multiple battery cells 500, which are first connected in series, parallel, or mixed to form the battery module 600. The multiple battery modules 600 are then connected in series, parallel, or mixed to form a whole and housed in a casing.

[0099] The structure of the battery cell will now be described with reference to the accompanying drawings.

[0100] Please refer to Figures 4 to 6. The battery cell 500 includes a housing 10 and an electrode assembly 20. The electrode assembly 20 is disposed inside the housing 10. The electrode assembly 20 includes a main body 23, a positive electrode tab 21, and a negative electrode tab 22. The positive electrode tab 21 and the negative electrode tab 22 are located on the same side of the main body 23 along a first direction X, which is the axial direction of the battery cell 500. At least a portion of the positive electrode tab 21 has a larger dimension in the first direction X than at least a portion of the negative electrode tab 22 has a larger dimension in the first direction X.

[0101] The battery cell 500 is a component structure used to provide electrical energy. The battery cell 500 has a housing 10, which is a hollow structure and serves to protect other component structures located inside it. Components such as the electrode assembly 20 can be housed inside the housing 10. The electrode assembly 20 is the main component in the electrode cell used to provide electrical energy.

[0102] The shape of the outer shell 10 can be determined according to the specific shape of the electrode assembly 20. That is, the shape of the outer shell 10 can be adapted to the shape of the electrode assembly 20. For example, when the electrode assembly 20 is a cylindrical structure, a cylindrical outer shell 10 can be used; when the electrode assembly 20 is a cuboid structure, a cuboid outer shell 10 can be used. Alternatively, depending on the actual needs, the shape of the outer shell 10 can also be different from the shape of the electrode assembly 20. For example, when the electrode assembly 20 is a cylindrical structure, the outer shell 10 can be a cuboid structure or other polygonal structure; when the electrode assembly 20 is a cuboid structure, the outer shell 10 can be a cylindrical structure.

[0103] The first direction X is the axial direction of the battery cell 500, which refers to the direction parallel to the central axis of the battery cell 500. For example, when the outer casing 10 is a cylindrical outer casing 10, the first direction X is perpendicular to the radial direction of the cylinder. When the outer casing 10 is a cuboid outer casing 10, the first direction is parallel to the length direction of the cuboid.

[0104] In some embodiments, the housing 10 can be a sealed structure or a non-sealed structure. As an example, when the housing 10 is a sealed structure, it can protect the electrode assembly 20 and, to some extent, prevent leakage such as electrolyte leakage. When the housing 10 is a non-sealed structure, it can still protect the electrode assembly 20, and a sealing bag may be included between the housing 10 and the electrode assembly 20. The sealing bag is used to encapsulate the electrode assembly 20 and the electrolyte, etc. Specifically, the sealing bag can be a bag-shaped insulating component or an aluminum-plastic film.

[0105] The electrode assembly 20 may include a positive electrode, a negative electrode, and an insulating element. The insulating element is located between the positive electrode and the negative electrode. Both the positive electrode and the negative electrode include a region covered by an active material layer and a region not covered by an active material layer.

[0106] The main body 23 is the main part of the electrode assembly 20. In addition to the separator, the main body 23 also includes partial structures in the positive and negative electrode plates corresponding to the separator in the first direction X. The separator typically extends beyond the area covered by the active material layer on the positive and negative electrode plates in the first direction X. Therefore, in addition to the structures covered by the active material layer on the positive and negative electrode plates, the main body 23 also includes partial structures on the positive and negative electrode plates that are not covered by the active material layer, and these partial structures are connected to the structures covered by the active material layer on the positive or negative electrode plates.

[0107] The positive electrode tab 21 and the negative electrode tab 22 are two tab components on the electrode assembly 20 used to connect with other structures to achieve electrical energy transfer. Optionally, the battery cell 500 may also include two electrode terminals disposed on the housing 10. The two electrode terminals are insulated from each other and electrically connected to the positive electrode tab 21 and the negative electrode tab 22 respectively. The electrode terminals are used to achieve electrical energy transfer between the inside and outside of the battery cell 500.

[0108] The positive electrode tab 21 is a partial structure in the area of ​​the positive electrode sheet that is not covered by the active material layer. The positive electrode tab 21 extends from one end of the main body 23 along the first direction X and is flattened or smoothed. The negative electrode tab 22 is a partial structure in the area of ​​the negative electrode sheet that is not covered by the active material layer. The negative electrode tab 22 extends from one end of the main body 23 along the first direction X and is flattened or smoothed.

[0109] Both the positive electrode tab 21 and the negative electrode tab 22 are formed by stacking and smoothing multiple layered structures. Specifically, taking the positive electrode tab 21 as an example, during the preparation of the electrode assembly 20, the area on the positive electrode sheet that is not covered with the active material layer can be cut to form multiple spaced layered structures. Then, the positive electrode sheet, the separator, and the negative electrode sheet are stacked in sequence and wound together. After winding, the multiple layered structures formed by cutting on the positive electrode sheet can be stacked accordingly. Then, the positive electrode tab 21 is formed by flattening or smoothing it. The negative electrode tab 22 is formed in the same way.

[0110] The positive electrode tab 21 and the negative electrode tab 22 extend from the same end of the main body 23 along the first direction X. Therefore, during the preparation of the battery cell 500, the positive electrode tab 21 and the negative electrode tab 22 are usually formed by kneading or smoothing together using the same equipment. Depending on the actual needs and different preparation processes, each position of the positive electrode tab 21 may be completely kneaded or smoothed, or only some positions of the positive electrode tab 21 may be kneaded or smoothed, while other positions may not be kneaded or smoothed. The same applies to the negative electrode tab 22.

[0111] Furthermore, in related technologies, the thickness of the flattened or smoothed positive electrode tab 21 can be the same as or similar to the height of the flattened negative electrode tab 22. However, due to the different materials and single-layer thicknesses of the positive electrode tab 21 and the negative electrode tab 22, their density is easily different. The difference in density often means that the positive electrode sheet and the negative electrode sheet are not as dense. Consequently, during the welding process, one of the positive electrode sheet and the negative electrode sheet may be too dense, causing the insulating component to be burned due to the welding process, or one of the positive electrode sheet and the negative electrode sheet may be too dense, resulting in poor welding of the solder joint. This can easily lead to the risk of peeling at the welding position during use.

[0112] It should be noted that the "density" mentioned in the embodiments of this application refers to the ratio of the mass of the fixed material portion to the total volume of the material. Specifically, if all locations of the positive electrode tab 21 are flattened or smoothed, the density of the positive electrode tab 21 is the ratio of the total weight of the positive electrode tab 21 to the total volume of the positive electrode tab 21. If only a portion of the positive electrode tab 21 is flattened or smoothed, the density of the positive electrode tab 21 is the ratio of the weight of the flattened or smoothed area of ​​the positive electrode tab 21 to the volume of the flattened or smoothed area of ​​the positive electrode tab 21. The density calculation method for the negative electrode tab 22 is similar.

[0113] In this embodiment, the height dimension of at least one of the positive electrode tab 21 and the negative electrode tab 22 in the first direction X is adjusted. Specifically, the negative electrode tab 22 can be further compressed so that at least part of the positive electrode tab 21 has a larger dimension in the first direction X than at least part of the negative electrode tab 22 in the first direction X, thereby reducing the density difference between the positive electrode tab 21 and the negative electrode tab 22, thereby improving the welding yield of the positive electrode tab 21 and the negative electrode tab 22 and improving the reliability of the battery cell 500.

[0114] It should be noted that the "dimension of at least a portion of the positive electrode tab 21 in the first direction X" mentioned in the embodiments of this application refers to the dimension of the flattened or smoothed structure in the positive electrode tab 21 in the first direction X. When the positive electrode tab 21 is completely flattened or smoothed, it corresponds to the dimension of all the structures in the positive electrode tab 21 in the first direction X. When only a part of the positive electrode tab 21 is flattened or smoothed, it corresponds to the dimension of a portion of the structure in the flattened or smoothed area of ​​the positive electrode tab 21 in the first direction X. The dimension of at least a portion of the negative electrode tab 22 in the first direction X is similar.

[0115] In some embodiments, please refer to Figures 4, 5 and 7. The electrode assembly 20 includes a plurality of first layer structures C1 stacked along the second direction Y and a plurality of second layer structures C2 stacked along the second direction Y. The first layer structures C1 and the second layer structures C2 are spaced apart. The plurality of first layer structures C1 form a positive electrode tab 21 and the plurality of second layer structures C2 form a negative electrode tab 22. The first direction X intersects the second direction Y. The thickness of the first layer structure C1 is greater than the thickness of the second layer structure C2.

[0116] As described above, both the positive electrode tab 21 and the negative electrode tab 22 can be formed by stacking and smoothing multiple layered structures. Specifically, the positive electrode tab 21 is formed by stacking and smoothing multiple first layered structures C1, which are arranged in the second direction Y. The negative electrode tab 22 is formed by stacking and smoothing multiple second layered structures C2, which are arranged in the second direction Y. Optionally, the first direction X is perpendicular to the second direction Y.

[0117] Furthermore, the thickness of a single first layer structure C1 in the second direction Y is greater than the thickness of a single second layer structure C2 in the second direction Y. Therefore, if the positive electrode tab 21 and the negative electrode tab 22 are flattened or smoothed to the same height, the density of the positive electrode tab 21 will be greater than that of the negative electrode tab 22, which will lead to poor welding.

[0118] In view of this, the negative electrode tab 22 is further compressed in this embodiment, so that the height dimension of the negative electrode tab 22 in the first direction X is smaller than the height dimension of the positive electrode tab 21 in the first direction X, thereby increasing the density of the negative electrode tab 22 and reducing the density difference between the positive electrode tab 21 and the negative electrode tab 22, which helps to improve the welding yield and improve the reliability of the battery cell 500.

[0119] In some embodiments, the positive electrode tab 21 is made of aluminum, and the negative electrode tab 22 is made of copper.

[0120] Compared to aluminum, copper requires a higher laser intensity during the welding process. This means that the negative electrode tab 22 requires a higher laser intensity. A higher laser intensity often means a higher density is required. If the density is insufficient, the separator may be burned during the welding process, affecting the reliability of the battery cell 500.

[0121] In view of this, the embodiments of this application adjust the height of the negative electrode tab 22 in the first direction X to be less than the height of the positive electrode tab 21 in the first direction X, so that the negative electrode tab 22 can be further compressed relative to the positive electrode tab 21, thereby improving the density of the negative electrode tab 22, reducing the risk of the separator being burned at the welding position corresponding to the negative electrode tab 22 during the welding process, and improving the preparation yield and reliability of the battery cell 500.

[0122] In some embodiments, as shown in Figures 4 and 5, the positive electrode tab 21 has a dimension of H1 in the first direction X, and the negative electrode tab 22 has a dimension of H2 in the first direction X, wherein H1 and H2 satisfy: 0.2mm ≤ H1 - H2 ≤ 1.5mm. Optionally, H1-H2 is one of 0.2mm, 0.4mm, 0.8mm, 1mm, 1.25mm, and 1.5mm.

[0123] The density of the tab is usually related to its height in the first direction X; the higher the tab, the lower its density. As mentioned above, if the density of the tab is too low, the insulating component is easily burned, while if the density of the tab is too high, the risk of poor welding is high. Therefore, it is necessary to control the density of the tab within a certain range.

[0124] In view of this, the embodiments of this application further restrict the height relationship between the positive electrode tab 21 and the negative electrode tab 22 in the first direction X, so that the height of the positive electrode tab 21 exceeding the negative electrode tab 22 in the first direction X is not less than 0.2 mm and not more than 1.5 mm, thereby ensuring that the density difference between the two can be controlled within a certain range. Thus, under the premise that one of the positive electrode tab 21 and the negative electrode tab 22 is welded reliably, the problem of the insulating component being burned or poorly welded at the corresponding welding position of the other is reduced, thereby improving the welding reliability of the positive electrode tab 21 and the negative electrode tab 22 and improving the preparation yield of the battery cell 500.

[0125] In some embodiments, the density R1 of the positive electrode tab 21 is 0.2 g / cm³ ≤ R1 ≤ 1 g / cm³, and / or the density R2 of the negative electrode tab 22 is 0.5 g / cm³ ≤ R2 ≤ 1.5 g / cm³. Optionally, the density R1 of the positive electrode tab 21 is one of 0.2 g / cm³, 0.4 g / cm³, 0.6 g / cm³, 0.8 g / cm³, and 1 g / cm³. And / or, the density R2 of the negative electrode tab 22 is one of 0.5 g / cm³, 0.8 g / cm³, 1 g / cm³, 1.2 g / cm³, and 1.5 g / cm³.

[0126] It should be noted that although the height of the positive electrode tab 21 in the first direction X is greater than the height of the negative electrode tab 22 in the first direction X, due to the differences in the materials corresponding to the positive electrode tab 21 and the negative electrode tab 22 and the thickness of the single-layer structure, the density of the positive electrode tab 21 can be less than the density of the negative electrode tab 22, or the density of the positive electrode tab 21 can be greater than or equal to the density of the negative electrode tab 22.

[0127] In this embodiment of the application, by limiting the density range of at least one of the positive electrode tab 21 and the negative electrode tab 22, the density difference between the positive electrode tab 21 and the negative electrode tab 22 is reduced, thereby reducing the risk of the insulating component being burned due to the low density of at least one of the positive electrode tab 21 and the negative electrode tab 22, and also helping to improve the welding strength of at least one of the positive electrode tab 21 and the negative electrode tab 22, thereby improving the preparation yield of the battery cell 500.

[0128] In some embodiments, the battery cell 500 further includes a positive terminal 31 and a negative terminal 32 disposed on the housing 10 and insulated from each other, the positive terminal 31 being electrically connected to the positive electrode tab 21 and the negative terminal 32 being electrically connected to the negative electrode tab 22.

[0129] The positive terminal 31 and the negative terminal 32 are two mutually insulated electrode terminals. The positive terminal 31 is used to enable electrical conduction between the positive electrode tab 21 and other external structures, and the negative terminal 32 is used to enable electrical conduction between the negative electrode tab 22 and other external structures. Optionally, a current collector 40 may also be provided inside the housing 10. The positive terminal 31 and the negative terminal 32 can be electrically connected to the positive electrode tab 21 and the negative electrode tab 22 respectively through two different current collectors 40, or the positive terminal 31 and the negative terminal 32 can also be electrically connected to the positive electrode tab 21 and the negative electrode tab 22 through different mutually insulated parts of the same current collector 40.

[0130] In this embodiment, the positive electrode tab 21 and the negative electrode tab 22 are located at the same end of the main body 23. They can be welded and fixed separately using the same laser equipment. Based on this, by adjusting the dimensions of the negative electrode tab 22 and the positive electrode tab 21 in the first direction X, the density between them is kept the same or similar, thereby improving the welding reliability of the corresponding positive electrode tab 21 and the negative electrode tab 22 and improving the preparation yield of the battery cell 500.

[0131] In some embodiments, as shown in FIG6, the battery cell 500 further includes a current collector 40, which includes a first connecting portion 41 connected to the positive electrode tab 21 and a second connecting portion 42 connected to the negative electrode tab 22. The first connecting portion 41 and the second connecting portion 42 are insulated from each other. The first connecting portion 41 has a first surface M1 facing the positive electrode tab 21, and the second connecting portion 42 has a second surface M2 facing the negative electrode tab 22. The first surface M1 is located on the side of the second surface M2 away from the main body portion 23.

[0132] The current collector 40 is used to achieve an electrical connection between the tab and the electrode terminal. The current collector 40 includes a first connecting portion 41 and a second connecting portion 42 that are insulated from each other. The first connecting portion 41 connects the positive tab 21 and the positive terminal 31 to achieve an electrical connection between the positive tab 21 and the positive terminal 31. The second connecting portion 42 connects the negative tab 22 and the negative terminal 32 to achieve an electrical connection between the negative tab 22 and the negative terminal 32. Optionally, the positive tab 21 is welded to the first connecting portion 41, and the negative tab 22 is welded to the second connecting portion 42.

[0133] Compared to the scheme where the positive electrode tab 21 and the negative electrode tab 22 are electrically connected to the corresponding electrode terminals by different current collectors 40, this design allows a single current collector 40 to simultaneously meet the electrical connection requirements between the positive electrode tab 21 and the positive terminal 31, as well as the connection requirements between the negative electrode tab 22 and the negative terminal 32. This reduces the overall size of the current collector 40, reduces the space occupied by the current collector 40 inside the casing 10, and helps to improve the corresponding energy density of the battery cell 500.

[0134] The first connecting portion 41 has a first surface M1 facing the positive electrode tab 21, which is the surface on the first connecting portion 41 used for contacting and connecting with the positive electrode tab 21. The second connecting portion 42 has a second surface M2 facing the negative electrode tab 22, which is the surface on the second connecting portion 42 used for contacting and connecting with the negative electrode tab 22.

[0135] Based on this, since the size of the positive electrode tab 21 in the first direction X is larger than the size of the negative electrode tab 22 in the first direction X, in order to meet the connection requirements of the first connecting part 41 and the second connecting part 42 relative to the positive electrode tab 21 and the negative electrode tab 22, the structure of at least one of the first connecting part 41 and the second connecting part 42 has been adjusted so that the first surface M1 in the first connecting part 41 is located on the side of the second surface M2 in the second connecting part 42 away from the main body, so that the first connecting part 41 and the second connecting part 42 are respectively matched and connected with the tabs of different heights to meet the connection requirements between the tabs and the current collector 40.

[0136] In some embodiments, referring to Figures 4 and 8, the current collector 40 further includes an insulating portion 43 disposed between the first connecting portion 41 and the second connecting portion 42. The first connecting portion 41 has a first connecting end D1 connected to the insulating portion 43, and the second connecting portion 42 has a second connecting end D2 connected to the insulating portion 43. The first connecting end D1 is located on the side of the second connecting end D2 away from the main body portion 23.

[0137] An insulating part 43 is sandwiched between the first connecting part 41 and the second connecting part 42. The insulating part 43 includes insulating material to achieve mutual insulation between the first connecting part 41 and the second connecting part 42. The insulating part 43 can be connected to the first connecting part 41 and the second connecting part 42 in various ways, such as by welding or bonding.

[0138] In this embodiment, the first connecting end D1 is the end structure on the first connecting portion 41 for connecting to the insulating portion 43, and the second connecting end D2 is the end structure on the second connecting portion 42 for connecting to the insulating portion 43. Further, in order to enable the first connecting portion 41 to adapt and contact with the positive electrode tab 21, and the second connecting portion 42 to adapt and contact with the negative electrode tab 22, this embodiment positions the first connecting end D1 on the side of the second connecting end D2 away from the main body portion 23. That is, the end of the first connecting portion 41 connected to the insulating member is farther from the main body portion 23 than the end of the second connecting portion 42 connected to the insulating member. This ensures that the first surface M1 is located on the side of the second surface M2 away from the main body portion 23, satisfying the contact requirements between the first surface M1 and the positive electrode tab 21, and the contact requirements between the second surface M2 and the negative electrode tab 22.

[0139] In some embodiments, referring to Figures 6 and 9, the first connecting portion 41 includes a first body portion 411 and a first protrusion 412 protruding from the first body portion 411 toward the positive electrode tab 21, the protrusion dimension of the first protrusion 412 relative to the first body portion 411 being L1. The second connecting portion 42 includes a second body portion 421 and a second protrusion 422 protruding from the second body portion 421 toward the negative electrode tab 22, the protrusion dimension of the second protrusion 422 relative to the second body portion 421 being L2, where L2 > L1.

[0140] The first body portion 411 is the main part of the first connecting portion 41. The first protrusion 412 is connected to the first body portion 411 and protrudes towards the positive electrode tab 21. The first protrusion 412 is a structure in the first connecting portion 41 used to connect the positive electrode tab 21. Further, the first surface M1 is the surface on the first protrusion 412 facing the positive electrode tab 21. Optionally, the first body portion 411 and the first protrusion 412 can be an integral structure.

[0141] The second body portion 421 is the main part of the second connecting portion 42. The second protrusion 422 is connected to the second body portion 421 and protrudes towards the negative electrode tab 22. The second protrusion 422 is a structure in the second connecting portion 42 used to connect the negative electrode tab 22. Further, the second surface M2 is the surface on the second protrusion 422 facing the negative electrode tab 22. Optionally, the second body portion 421 and the second protrusion 422 can be an integral structure.

[0142] In this embodiment, in order to enable the first protrusion 412 to contact and connect with the positive electrode tab 21 and the second protrusion 422 to contact and connect with the negative electrode tab 22, the protrusion dimensions of the first protrusion 412 and the second protrusion 422 are limited, so that the protrusion dimension L1 of the first protrusion 412 relative to the first body portion 411 is smaller than the protrusion dimension L2 of the second protrusion 422 relative to the second body portion 421. That is, the second protrusion 422 protrudes closer to the body portion than the first protrusion 412, so as to achieve the contact connection between the first protrusion 412 and the positive electrode tab 21 and the contact connection between the second protrusion 422 and the negative electrode tab 22, which has strong practicality.

[0143] It should be noted that, depending on the actual needs, the first connecting end D1 can be located on the side of the second connecting end D2 away from the main body 23, and the protrusion dimension L1 of the first protrusion 412 can be equal to the protrusion dimension L2 of the second protrusion 422. Alternatively, the first connecting end D1 and the second connecting end D2 can be set at the same height in the first direction X, and the protrusion dimension L1 of the first protrusion 412 can be smaller than the protrusion dimension L2 of the second protrusion 422. Alternatively, the first connecting end D1 can be located on the side of the second connecting end D2 away from the main body 23, and the protrusion dimension L1 of the first protrusion 412 can be smaller than the protrusion dimension L2 of the second protrusion 422. Of course, other methods can also be chosen, as long as the first surface M1 is located on the side of the second surface M2 away from the main body 23.

[0144] In some embodiments, the battery cell 500 is a cylindrical battery cell 500.

[0145] In this embodiment, considering the potential welding defects in the cylindrical battery cell 500, the negative electrode tab 22 in the cylindrical battery cell 500 is further compressed, making the size of the positive electrode tab 21 in the first direction X larger than the size of the negative electrode tab 22 in the first direction X. This reduces the density difference between the positive electrode tab 21 and the negative electrode tab 22, thereby improving the welding yield of the positive electrode tab 21 and the negative electrode tab 22 and improving the manufacturing reliability of the cylindrical battery cell 500.

[0146] Secondly, embodiments of this application provide a battery, which includes the battery cell 500 in any of the foregoing embodiments.

[0147] It should be noted that the battery provided in this application embodiment has the beneficial effects of the battery cell 500 in any of the foregoing embodiments. For details, please refer to the foregoing description of the beneficial effects of the battery cell 500. This application embodiment will not repeat the description.

[0148] Thirdly, this application provides an electrical device, which includes a battery cell 500 as described in any of the foregoing embodiments, and the battery cell 500 is used to provide electrical energy.

[0149] It should be noted that the electrical device provided in this application embodiment has the beneficial effects of the battery cell 500 in any of the foregoing embodiments. For details, please refer to the foregoing description of the beneficial effects of the battery cell 500. This application embodiment will not repeat the description.

[0150] According to some embodiments of this application, please refer to Figures 4 to 6. The battery cell 500 includes a housing 10, an electrode assembly 20, a positive terminal 31, a negative terminal 32, and a current collector 40. The electrode assembly 20 is disposed inside the housing 10. The electrode assembly 20 includes a main body 23, a positive electrode tab 21, and a negative electrode tab 22. The positive electrode tab 21 extends from one end of the main body 23 along a first direction X and is flattened or smoothed. The negative electrode tab 22 extends from one side of the main body 23 along the first direction X and is flattened or smoothed. The size of the positive electrode tab 21 in the first direction X is larger than the size of the negative electrode tab 22 in the first direction X.

[0151] The electrode assembly 20 includes multiple layered structures stacked along the second direction Y, and multiple second layered structures C2 stacked along the second direction Y. First layered structures C1 and second layered structures C2 are spaced apart. The multiple first layered structures C1 are flattened or smoothed to form a positive electrode tab 21, and the multiple second layered structures C2 are flattened or smoothed to form a negative electrode tab 22. The first direction X intersects the second direction Y, and the thickness of the first layered structure C1 is greater than the thickness of the second layered structure C2. The positive electrode tab 21 is made of aluminum, and the negative electrode tab 22 is made of copper.

[0152] The positive electrode tab 21 has a dimension of H1 in the first direction X, and the negative electrode tab 22 has a dimension of H2 in the first direction X. H1 and H2 satisfy: 0.2mm ≤ H1 - H2 ≤ 1.5mm. The density R1 of the positive electrode tab 21 is 0.2g / cm3 ≤ R1 ≤ 1g / cm3, and / or the density R2 of the negative electrode tab 22 is 0.5g / cm3 ≤ R2 ≤ 1.5g / cm3.

[0153] The positive electrode tab 21 and the negative electrode tab 22 are located on the same side of the main body 23. The battery cell 500 also includes a positive terminal 31 and a negative terminal 32 disposed on the outer casing 10 and insulated from each other. The positive terminal 31 is electrically connected to the positive electrode tab 21, and the negative terminal 32 is electrically connected to the negative electrode tab 22. The battery cell 500 also includes a current collector 40, which includes a first connecting portion 41 connected to the positive electrode tab 21 and a second connecting portion 42 connected to the negative electrode tab 22. The first connecting portion 41 and the second connecting portion 42 are insulated from each other. The first connecting portion 41 has a first surface M1 facing the positive electrode tab 21, and the second connecting portion 42 has a second surface M2 facing the negative electrode tab 22. The first surface M1 is located on the side of the second surface M2 away from the main body 23.

[0154] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A single battery cell, comprising: shell; An electrode assembly is disposed within the housing. The electrode assembly includes a main body, a positive electrode tab, and a negative electrode tab. The positive electrode tab and the negative electrode tab are located on the same side of the main body along a first direction, which is the axial direction of the battery cell. At least a portion of the positive electrode tab has a larger dimension in the first direction than at least a portion of the negative electrode tab has a larger dimension in the first direction.

2. The battery cell according to claim 1, wherein, The electrode assembly includes a plurality of first layer structures stacked along a second direction and a plurality of second layer structures stacked along the second direction, wherein the first layer structures and the second layer structures are spaced apart, the plurality of first layer structures form the positive electrode tab, and the plurality of second layer structures form the negative electrode tab, wherein the first direction and the second direction intersect. The thickness of the first layer is greater than the thickness of the second layer.

3. The battery cell according to claim 1, wherein, The positive electrode tab is made of aluminum, and the negative electrode tab is made of copper.

4. The battery cell according to claim 1, wherein, The positive electrode tab has a dimension of H1 in the first direction, and the negative electrode tab has a dimension of H2 in the first direction. H1 and H2 satisfy: 0.2mm≤H1-H2≤1.5mm.

5. The battery cell according to claim 1, wherein, The density R1 of the positive electrode tab is 0.2 g / cm3 ≤ R1 ≤ 1 g / cm3, and / or the density R2 of the negative electrode tab is 0.5 g / cm3 ≤ R2 ≤ 1.5 g / cm3.

6. The battery cell according to claim 1, wherein, The battery cell also includes a positive terminal and a negative terminal disposed on the outer casing and insulated from each other. The positive terminal is electrically connected to the positive electrode tab, and the negative terminal is electrically connected to the negative electrode tab.

7. The battery cell according to claim 5 further includes a current collector, the current collector including a first connecting portion connected to the positive electrode tab and a second connecting portion connected to the negative electrode tab, the first connecting portion and the second connecting portion being insulated from each other; The first connecting portion has a first surface facing the positive electrode tab, and the second connecting portion has a second surface facing the negative electrode tab, with the first surface located on the side of the second surface away from the main body.

8. The battery cell according to claim 7, wherein, The current collecting component further includes an insulating portion disposed between the first connecting portion and the second connecting portion, wherein the first connecting portion has a first connecting end connected to the insulating portion, and the second connecting portion has a second connecting end connected to the insulating portion; The first connecting end is located on the side of the second connecting end away from the main body.

9. The battery cell according to claim 7, wherein, The first connecting portion includes a first body portion and a first protrusion portion protruding from the first body portion toward the positive electrode tab, wherein the protrusion dimension of the first protrusion portion relative to the first body portion is L1; The second connecting portion includes a second body portion and a second protrusion portion protruding from the second body portion toward the negative electrode tab. The protrusion dimension of the second protrusion portion relative to the second body portion is L2, where L1 > L2.

10. The battery cell according to claim 1, wherein, The battery cell is a cylindrical battery cell.

11. A battery comprising a battery cell as described in any one of claims 1 to 10.

12. An electrical device comprising a battery cell as described in any one of claims 1 to 10, the battery cell being used to provide electrical energy.

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