Battery monomer, battery and electric device

Abstract

The utility model provides a battery monomer, a battery and a power utilization device, the battery monomer comprises 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 lug and a negative electrode lug, the positive electrode lug and the negative electrode lug 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 monomer, and the first direction is the axial direction of the battery monomer. The size of at least part of the positive electrode tab in the first direction is greater than that of at least part of the negative electrode tab in the first direction. In the embodiment of the invention, the height size of at least one of the positive pole lug and the negative pole lug in the first direction is adjusted, specifically, the negative pole lug can be further compressed to reduce the corresponding compactness difference between the positive pole lug and the negative pole lug, so that the corresponding welding yield of the positive pole lug and the negative pole lug is improved; and the preparation reliability of the battery monomer is improved.

Description

Technical Field

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

[0002] Battery cells 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. Battery cells can include nickel-cadmium battery cells, nickel-hydrogen battery cells, lithium-ion battery cells, and secondary alkaline zinc-manganese battery cells, etc.

[0003] In the development of battery technology, how to improve battery reliability has always been a research direction in battery technology. Utility Model Content

[0004] In view of the above problems, the present application provides a battery cell, a battery and an electrical device, which can improve the preparation yield of the battery cell.

[0005] On the one hand, an embodiment of the present application provides a battery cell, including a shell and an electrode assembly, wherein the electrode assembly is disposed in the shell, and the electrode assembly includes a main body, a positive electrode tab and a negative electrode tab, wherein the positive electrode tab and the negative electrode tab are located on the same side of the main body along a first direction, wherein 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.

[0006] 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, the negative electrode tab can be further compressed so that the dimension of at least part of the positive electrode tab in the first direction is larger than the dimension of at least part of the negative electrode tab in the first direction, thereby reducing the density difference between the positive electrode tab and the negative electrode tab, thereby improving the corresponding welding yield of the positive electrode tab and the negative electrode tab and improving the preparation reliability of the battery cell.

[0007] In some embodiments, 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, the first layer structures and the second layer structures are spaced apart, the plurality of first layer structures form positive electrode tabs, the plurality of second layer structures form negative electrode tabs, the first direction intersects with the second direction, and the thickness of the first layer structure is greater than the thickness of the second layer structure.

[0008] In the above scheme, the negative electrode tab is further compressed so that the height dimension of the negative electrode tab in the first direction is smaller than the height dimension of the positive electrode tab in the first direction, thereby increasing the corresponding density of the negative electrode tab, thereby reducing the density difference between the positive electrode tab and the negative electrode tab, which helps to improve the welding yield and improve the preparation reliability of the battery cell.

[0009] In some embodiments, the material of the positive electrode tab includes metal aluminum, and the material of the negative electrode tab includes metal copper.

[0010] In the above scheme, by adjusting the height of the negative electrode tab in the first direction to be smaller 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 improving the corresponding density of the negative electrode tab, reducing the risk of burning of the isolation piece at the welding position corresponding to the negative electrode tab during welding, and improving the preparation yield and reliability of the battery cell.

[0011] In some embodiments, the dimension of the positive electrode tab in the first direction is H1, and the dimension of the negative electrode tab in the first direction is H2, and H1 and H2 satisfy: 0.2 mm ≤ H1 - H2 ≤ 1.5 mm.

[0012] In the above scheme, the height relationship between the positive electrode tab and the negative electrode tab in the first direction is further restricted, so that the height of the positive electrode tab in the first direction exceeds the negative electrode tab by 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. Further, when one of the positive electrode tab and the negative electrode tab is welded reliably, the problem of the insulating member being burned or the welding being poor at the corresponding welding position of the other electrode is reduced, thereby improving the corresponding welding reliability of the positive electrode tab and the negative electrode tab and improving the preparation yield of the battery cell.

[0013] In some embodiments, 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.

[0014] In the above scheme, by limiting the density range of at least one of the positive electrode lug and the negative electrode lug, the density difference between the positive electrode lug and the negative electrode lug is reduced, and the risk of burning the isolation member due to too low density of at least one of the positive electrode lug and the negative electrode lug is reduced. It also helps to improve the corresponding welding strength of at least one of the positive electrode lug and the negative electrode lug, thereby improving the preparation yield of the battery cell.

[0015] In some embodiments, the battery cell further includes a positive terminal and a negative terminal which are disposed on the housing 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.

[0016] In the above scheme, the positive electrode tab and the negative electrode tab are located at the same end of the main body, and the two can be welded and fixed respectively by means of the same laser equipment. On this basis, by adjusting the dimensions of the negative electrode tab and the positive electrode tab in the first direction, the density between the two can be kept the same or similar, thereby improving the corresponding welding reliability of the positive electrode tab and the negative electrode tab and improving the preparation yield of the battery cell.

[0017] In some embodiments, the battery cell further includes a current collecting member, the current collecting member includes 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 are insulated from each other. The first connecting portion has a first surface facing the positive electrode tab, the second connecting portion has a second surface facing the negative electrode tab, and the first surface is located on a side of the second surface away from the main body.

[0018] In the above scheme, since the size of the positive electrode tab in the first direction is larger than the size of the negative electrode tab in the first direction, in order to meet the connection needs of the first connecting portion and the second connecting portion relative to the positive electrode tab and the negative electrode tab, the embodiment of the present application adjusts the structure of at least one of the first connecting portion and the second connecting portion, so that the first surface in the first connecting portion is located on the side of the second surface in the second connecting portion away from the main body, so that the first connecting portion and the second connecting portion are respectively matched and connected with the tabs of different heights, thereby meeting the connection needs between the tabs and the current collecting components.

[0019] In some embodiments, the current collecting component also includes an insulating part arranged between the first connecting part and the second connecting part, the first connecting part has a first connecting end connected to the insulating part, the second connecting part has a second connecting end connected to the insulating part, and the first connecting end is located on a side of the second connecting end away from the main body.

[0020] In the above scheme, the first connection end is an end structure on the first connection part for connecting to the insulating part, and the second connection end is an end structure on the second connection part for connecting to the insulating part. Further, in order to enable the first connection part to fit and contact with the positive electrode tab, and the second connection part to fit and contact with the negative electrode tab, the embodiment of the present application sets the first connection end on the side of the second connection end away from the main body, that is, the end of the first connection part connected to the insulating member is farther from the main body than the end of the second connection part connected to the insulating member, so that the first surface is located on the side of the second surface away from the main body, meeting the contact needs of the first surface with the positive electrode tab and the contact needs of the second surface with the negative electrode tab.

[0021] In some embodiments, the first connection portion includes a first body portion and a first protrusion protruding from the first body portion toward the positive electrode tab, and the protrusion dimension of the first protrusion relative to the first body portion is L1. The second connection portion includes a second body portion and a second protrusion protruding from the second body portion toward the negative electrode tab, and the protrusion dimension of the second protrusion relative to the second body portion is L2, and L2>L1.

[0022] In the above scheme, in order to enable the first protrusion to contact and connect with the positive electrode tab and the second protrusion to contact and connect with the negative electrode tab, the protrusion dimensions corresponding to the first protrusion and the second protrusion are restricted, so that the protrusion dimension L1 of the first protrusion relative to the first main body is smaller than the protrusion dimension L2 of the second protrusion relative to the second main body, that is, the second protrusion protrudes closer to the main body relative to the first protrusion, so as to achieve contact connection between the first protrusion and the positive electrode tab, and contact connection between the second protrusion and the negative electrode tab, which has strong practicality.

[0023] In some embodiments, the battery cells are cylindrical battery cells.

[0024] In the above scheme, considering that there may be a problem of poor welding in the cylindrical battery cell, the negative electrode tab in the cylindrical battery cell is further compressed, so that the size of the positive electrode tab in the first direction is larger than the size of the negative electrode tab in the first direction, thereby reducing the density difference between the positive electrode tab and the negative electrode tab, thereby improving the corresponding welding yield of the positive electrode tab and the negative electrode tab, and improving the preparation reliability of the cylindrical battery cell.

[0025] In a second aspect, an embodiment of the present application provides a battery, the battery comprising a battery cell in any of the aforementioned embodiments.

[0026] In a third aspect, an embodiment of the present application provides an electrical device, which includes a battery cell in any of the aforementioned embodiments, and the battery cell is used to provide electrical energy.

[0027] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] 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 these drawings without creative work.

[0029] Figure 1 is a structural schematic diagram of a vehicle provided in an embodiment of the present application;

[0030] Figure 2 is a schematic diagram of an exploded structure of a battery provided in an embodiment of the present application;

[0031] Figure 3 is a schematic diagram of the internal structure of a battery module provided in an embodiment of the present application;

[0032] Figure 4 is a schematic diagram of an exploded structure of a battery cell provided in an embodiment of the present application;

[0033] Figure 5 is a schematic diagram of a cross-sectional structure of a battery cell provided in an embodiment of the present application;

[0034] Figure 6 yes Figure 5 Schematic diagram of the enlarged structure of the middle region Q;

[0035] Figure 7 This is a schematic structural diagram of an electrode assembly in another battery cell before flattening provided in an embodiment of the present application;

[0036] Figure 8 is a structural schematic diagram of a current collecting component in a battery cell provided in an embodiment of the present application;

[0037] Fig. 9 It is a schematic structural diagram of another current collecting component in a battery cell provided in an embodiment of the present application.

[0038] In the attached figure:

[0039] 1000. Vehicles;

[0040] 100, battery; 200, controller; 300, motor; 400, housing; 401, first housing portion; 402, second housing portion; 403, storage portion; 500, battery cell; 600, battery module;

[0041] 10. Shell;

[0042] 20. electrode assembly; 21. positive electrode tab; 22. negative electrode tab; 23. main body;

[0043] 31. Positive terminal; 32. Negative terminal;

[0044] 40. current collecting member; 41. first connecting portion; 411. first main body portion; 412. first protruding portion; 42. second connecting portion; 421. second main body portion; 422. second protruding portion; 43. insulating portion;

[0045] C1, first layer structure; C2, second layer structure;

[0046] D1, first connection end; D2, second connection end;

[0047] M1, first surface; M2, second surface;

[0048] X, first direction; Y, second direction. DETAILED DESCRIPTION

[0049] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein 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 figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0051] 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 "multiple" is more than two, unless otherwise clearly and specifically defined.

[0052] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations 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. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0053] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may 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 article generally indicates that the associated objects before and after are in an "or" relationship.

[0054] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0055] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which 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 referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0056] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like 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 mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0057] 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.

[0058] 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 storage battery, etc., which is not limited in the embodiments of the present application.

[0059] A battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are embedded and removed back and forth between the positive electrode and the negative electrode. The separator is set between the positive electrode and the negative electrode, which can prevent the positive and negative electrodes from short-circuiting to a certain extent, while allowing active ions to pass through.

[0060] 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.

[0061] 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.

[0062] 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.).

[0063] 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. Among them, examples of lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.

[0064] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0065] As an example, the negative electrode current collector can be a metal foil, a foamed metal 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, or a foamed carbon, 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.).

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0071] 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.

[0072] As an example, the main material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramics.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] In some embodiments, the electrode assembly is a laminate structure.

[0077] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0078] 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.

[0079] 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.

[0080] In some embodiments, the housing may be provided with functional components such as electrode terminals, etc. The electrode terminals may be used to electrically connect to the electrode assembly to output or input electrical energy of the battery cell.

[0081] In some embodiments, a current collecting member may be disposed in the housing, and the electrode assembly may be electrically connected to the housing or an electrode terminal disposed on the housing through the current collecting member.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] In some embodiments, the battery may be an energy storage device, which includes an energy storage container, an energy storage cabinet, and the like.

[0088] As an important component in a battery cell, the electrode assembly usually uses a tab to electrically connect to the electrode terminal on the battery cell to realize the charging and discharging of the battery cell. Before connecting the tab to the electrode terminal, the tab needs to be flattened or smoothed so that the tab has a predetermined density to achieve the strength of welding with the electrode terminal. However, due to the different materials and single-layer structure thickness of the positive and negative tabs, the related technology usually flattens or smoothes the dimensions of the positive and negative tabs to the same height. When one of the positive and negative tabs reaches the predetermined density, the other may not reach the predetermined density, which leads to poor welding during welding with the electrode terminal, which is not conducive to improving the reliability of the battery cell.

[0089] Based on the above technical problems, the present 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 the first direction, thereby reducing the density difference between the positive electrode tab and the negative electrode tab, thereby improving the corresponding welding yield of the positive electrode tab and the negative electrode tab and improving the preparation reliability of the battery cell.

[0090] The technical solutions described in the embodiments of the present application are applicable to batteries and electrical devices using batteries, such as mobile phones, portable devices, laptop computers, electric vehicles, electric cars, ships, spacecraft, electric toys and electric tools, etc., wherein spacecrafts include airplanes, rockets, space shuttles and spacecrafts, etc., electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc., and electric tools include metal cutting power tools, grinding power tools, assembly power tools and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators and electric planers.

[0091] The battery cells described in the embodiments of the present application are not limited to being applicable to the electrical devices described above, but for the sake of simplicity, the following embodiments are described using electric vehicles as examples.

[0092] See also Figure 1 , Figure 1 A simple schematic diagram of a vehicle 1000 provided in an embodiment of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 may be provided inside the vehicle 1000, and specifically, for example, the battery 100 may be provided at the bottom, front or rear of the vehicle 1000. The battery 100 may be used to power the vehicle 1000, for example, the battery 100 may be used as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300, and the controller 200 is used, for example, to control the battery to power the motor 300. The battery may be used for starting and navigating the vehicle 1000, and of course, the battery 100 may also be used to drive the vehicle 1000, replacing or partially replacing fuel or natural gas to provide drive for the vehicle 1000.

[0093] Figure 2 Schematic diagram of an explosion of a battery provided in some embodiments of the present application. Figure 2 As shown, the battery 100 includes a housing 400 and a battery cell (not shown in the figure), and the battery cell is accommodated in the housing 400 .

[0094] The box 400 is used to accommodate the battery cell, and the box 400 can be a variety of structures. In some embodiments, the box 400 may include a first box portion 401 and a second box portion 402, the first box portion 401 and the second box portion 402 cover each other, and the first box portion 401 and the second box portion 402 jointly define a receiving portion 403 for accommodating the battery cell. The second box portion 402 may be a hollow structure with one end open, the first box portion 401 is a plate-like structure, and the first box portion 401 covers the open side of the second box portion 402 to form a box with a receiving portion 403; the first box portion 401 and the second box portion 402 may also be a hollow structure with one side open, and the open side of the first box portion 401 covers the open side of the second box portion 402 to form a box 400 with a receiving portion. Of course, the first box portion 401 and the second box portion 402 may be in a variety of shapes, such as a cylinder, a cuboid, etc.

[0095] In the battery 100, 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 multiple battery cells are connected in series and in parallel. 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 400; of course, multiple battery cells can also be connected in series, in parallel, or in mixed connection to form a battery module 600, and multiple battery modules 600 are then connected in series, in parallel, or in mixed connection to form a whole, and accommodated in the box 400.

[0096] Figure 3 for Figure 2 FIG. 6 is a schematic diagram of an exploded structure of a battery module 600. Figure 3 As shown, there are multiple battery cells 500, and the multiple battery cells 500 are first connected in series, in parallel, or in mixed series to form a battery module 600. The multiple battery modules 600 are then connected in series, in parallel, or in mixed series to form a whole, and are accommodated in a box.

[0097] Next, the structure of the battery cell will be described with reference to the accompanying drawings.

[0098] See also Figures 4 to 6 The battery cell 500 includes a shell 10 and an electrode assembly 20, the electrode assembly 20 is arranged in the shell 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, the first direction X is the axial direction of the battery cell 500, and the size of at least part of the positive electrode tab 21 in the first direction X is greater than the size of at least part of the negative electrode tab 22 in the first direction X.

[0099] The battery cell 500 is a component structure for providing electric energy. The battery cell 500 is provided with a housing 10. The housing 10 is a hollow structure and is used to protect other component structures located inside it. Components such as the electrode assembly 20 can be arranged inside the housing 10. The electrode assembly 20 is the main component in the electrode cell for providing electric energy.

[0100] The shape of the shell 10 can be determined according to the specific shape of the electrode assembly 20, that is, the shape of the 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 shell 10 can be selected; when the electrode assembly 20 is a rectangular parallelepiped structure, a rectangular parallelepiped shell 10 can be selected. Or according to different actual needs, the shape of the 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 shell 10 can be a rectangular parallelepiped structure or other polygonal structures; when the electrode assembly 20 is a rectangular parallelepiped structure, the shell 10 can be a cylindrical structure.

[0101] The first direction X is the axial direction of the battery cell 500. The axial direction mentioned here refers to the direction parallel to the central axis of the battery cell 500. For example, when the housing 10 is a cylindrical housing 10, the first direction X is a direction perpendicular to the radial direction of the cylinder. When the housing 10 is a rectangular housing 10, the first direction is a direction parallel to the length direction of the rectangular housing.

[0102] In some embodiments, the housing 10 may be a sealed structure or a non-sealed structure. As an example, when the housing 10 is a sealed structure, the housing 10 may protect the electrode assembly 20 and prevent electrolyte leakage to a certain extent. When the housing 10 is a non-sealed structure, the housing 10 may protect the electrode assembly 20, and a sealing bag may be included between the housing 10 and the electrode assembly 20, and the sealing bag is used to encapsulate the electrode assembly 20 and the electrolyte. Specifically, the sealing bag may be a bag-shaped insulating member or an aluminum-plastic film.

[0103] The electrode assembly 20 may include a positive electrode sheet, a negative electrode sheet, and a separator, wherein the separator is located between the positive electrode sheet and the negative electrode sheet, and each of the positive electrode sheet and the negative electrode sheet includes a region covered with an active material layer and a region not covered with the active material layer.

[0104] The main body 23 is the main part of the electrode assembly 20. In addition to the separator, the main body 23 also includes a partial structure provided in the positive electrode sheet and the negative electrode sheet corresponding to the separator in the first direction X, wherein the separator generally exceeds the area covered with the active material layer on the positive electrode sheet and the negative electrode sheet in the first direction X. Therefore, in addition to the structure covered with the active material layer on the positive electrode sheet and the negative electrode sheet, the main body 23 also includes a partial structure not covered with the active material layer on the positive electrode sheet and the negative electrode sheet, and the partial structure is connected to the structure covered with the active material layer on the positive electrode sheet or the negative electrode sheet.

[0105] The positive electrode tab 21 and the negative electrode tab 22 are two tab components on the electrode assembly 20 for connecting with other structures to achieve power transmission. 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 are electrically connected to the positive electrode tab 21 and the negative electrode tab 22, respectively, and the electrode terminals are used to achieve power transmission between the inside and outside of the battery cell 500.

[0106] The positive electrode tab 21 is a partial structure in the area of ​​the positive electrode sheet that is not covered with 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 with 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.

[0107] The positive electrode tab 21 and the negative electrode tab 22 are both formed by stacking multiple layer structures and kneading or smoothing them. 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 first to form multiple layer structures that are spaced apart, and then the positive electrode sheet, the separator and the negative electrode sheet need to be stacked in sequence and the three are wound together, so that after the winding is completed, the multiple layer structures cut on the positive electrode sheet can be stacked accordingly, and then the positive electrode tab 21 is formed by kneading or smoothing it, and the negative electrode tab 22 is the same.

[0108] 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 process of the battery cell 500, the positive electrode tab 21 and the negative electrode tab 22 are usually kneaded or smoothed together using the same equipment. According to actual needs and different preparation processes, each position of the positive electrode tab 21 can be completely kneaded or smoothed, or only part of the positive electrode tab 21 is kneaded or smoothed, while other positions are not kneaded or smoothed, and the negative electrode tab 22 is the same.

[0109] Furthermore, in the related art, the thickness dimension of the flattened or smoothed positive electrode tab 21 can be the same or similar to the height dimension of the flattened negative electrode tab 22, but since the materials and the thickness of the single-layer structure corresponding to the positive electrode tab 21 and the negative electrode tab 22 are different, it is easy to cause the corresponding densities of the two to be different, and the difference in density often means that the corresponding density of the positive electrode sheet and the negative electrode sheet is different. As a result, during the welding process, one of the positive electrode sheet and the negative electrode sheet may have too low density, resulting in the insulation being burned due to the welding process, or one of the positive electrode sheet and the negative electrode sheet may have too high density, resulting in poor welding of the weld, which is prone to the risk of peeling at the welding position during use.

[0110] It should be noted that the "compactness" mentioned in the embodiments of the present application refers to: the ratio of the mass of the fixed material part of the material to the total volume. Specifically, if all positions of the positive electrode tab 21 are flattened or smoothed, the compactness 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 part of the positive electrode tab 21 is flattened or smoothed, the compactness 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 calculation method of the compactness corresponding to the negative electrode tab 22 is similar.

[0111] In the embodiment of the present application, 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 the dimension of at least a portion of the positive electrode tab 21 in the first direction X is greater than the dimension of at least a portion 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 corresponding welding yield of the positive electrode tab 21 and the negative electrode tab 22, and improving the preparation reliability of the battery cell 500.

[0112] It should be noted that the "size of at least part of the positive electrode tab 21 in the first direction X" mentioned in the embodiment of the present application refers to: the size 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 size of the entire structure 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 size of the part of the structure of the positive electrode tab 21 in the flattened or smoothed area in the first direction X. The size of at least part of the negative electrode tab 22 in the first direction X is similar.

[0113] In some embodiments, see Figure 4 , Figure 5 as well as Figure 7The 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 from each other. 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 with the second direction Y, and the thickness of the first layer structure C1 is greater than the thickness of the second layer structure C2.

[0114] In combination with the above content, it can be known that the positive electrode tab 21 and the negative electrode tab 22 can be formed by stacking and flattening or smoothing a plurality of layer structures. Specifically, the positive electrode tab 21 is formed by stacking and flattening or smoothing a plurality of first layer structures C1, and the plurality of first layer structures C1 are arranged in the second direction Y. The negative electrode tab 22 is formed by stacking and flattening or smoothing a plurality of second layer structures C2, and the plurality of second layer structures C2 are arranged in the second direction Y. Optionally, the first direction X is perpendicular to the second direction Y.

[0115] Furthermore, the thickness dimension of the single first layer structure C1 in the second direction Y is greater than the thickness dimension of the 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 the density of the negative electrode tab 22, thereby causing poor welding problems.

[0116] In view of this, the embodiment of the present application further compresses the negative electrode tab 22 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 corresponding density of the negative electrode tab 22, thereby 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 preparation reliability of the battery cell 500.

[0117] In some embodiments, the material of the positive electrode tab 21 includes metal aluminum, and the material of the negative electrode tab 22 includes metal copper.

[0118] Compared with metal aluminum, during the welding process, the laser intensity required for metal copper is greater, that is, the negative electrode tab 22 requires a greater laser intensity. A greater laser intensity often means that a greater density needs to be matched. If the density is insufficient, it is easy to cause the isolation component to be burned during the welding process, affecting the preparation reliability of the battery cell 500.

[0119] In view of this, the embodiment of the present application adjusts the height of the negative electrode tab 22 in the first direction X to be smaller 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 corresponding density of the negative electrode tab 22, reducing the risk of the isolation piece being burned at the corresponding welding position of the negative electrode tab 22 during welding, and improving the preparation yield and reliability of the battery cell 500.

[0120] In some embodiments, Figure 4 and Figure 5 As shown, the size of the positive electrode tab 21 in the first direction X is H1, and the size of the negative electrode tab 22 in the first direction X is H2, and 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.

[0121] The density of the tab is usually related to its height in the first direction X. The higher the height of the tab, the lower its density. As can be seen from the above, if the density of the tab is too low, the separator may be burned. If the density of the tab is too high, the risk of poor welding may be caused. Therefore, the density of the tab needs to be controlled within a certain range.

[0122] In view of this, the embodiment of the present application further limits 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. Further, when one of the positive electrode tab 21 and the negative electrode tab 22 is welded reliably, the problem of the isolation piece being burned or the welding being poor at the corresponding welding position of the other electrode is reduced, thereby improving the corresponding welding reliability of the positive electrode tab 21 and the negative electrode tab 22, and improving the preparation yield of the battery cell 500.

[0123] In some embodiments, 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. Optionally, the density R1 of the positive electrode tab 21 is one of 0.2g / cm3, 0.4g / cm3, 0.6g / cm3, 0.8g / cm3 and 1g / cm3. And / or, the density R2 of the negative electrode tab 22 is one of 0.5g / cm3, 0.8g / cm3, 1g / cm3, 1.2g / cm3 and 1.5g / cm3.

[0124] 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 may be less than the density of the negative electrode tab 22, or the density of the positive electrode tab 21 may be greater than or equal to the density of the negative electrode tab 22.

[0125] In the embodiment of the present 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, and the risk of burning the isolation component due to too low density of at least one of the positive electrode tab 21 and the negative electrode tab 22 is reduced, and it helps to improve the corresponding 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.

[0126] In some embodiments, the battery cell 500 further includes a positive terminal 31 and a negative terminal 32 which are disposed on the housing 10 and are 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 .

[0127] The positive terminal 31 and the negative terminal 32 are two electrode terminals insulated from each other. The positive terminal 31 is used to achieve electrical conduction between the positive electrode tab 21 and other external structures, and the negative terminal 32 is used to test the electrical conduction between the negative electrode tab 22 and other external structures. Optionally, a current collecting component 40 may also be provided in the housing 10. The positive terminal 31 and the negative terminal 32 may be electrically connected to the positive electrode tab 21 and the negative electrode tab 22 respectively through two different current collecting components 40, or the positive terminal 31 and the negative terminal 32 may 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 collecting component 40.

[0128] In the embodiment of the present application, the positive electrode tab 21 and the negative electrode tab 22 are located at the same end of the main body 23, and the two can be welded and fixed separately by means of the same laser equipment. On this basis, by adjusting the dimensions of the negative electrode tab 22 and the positive electrode tab 21 in the first direction X, the density between the two is kept the same or similar, thereby improving the corresponding welding reliability of the positive electrode tab 21 and the negative electrode tab 22, and improving the preparation yield of the battery cell 500.

[0129] In some embodiments, Figure 6As shown, the battery cell 500 further includes a current collecting member 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, and 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, and the first surface M1 is located on a side of the second surface M2 away from the main body 23.

[0130] The current collecting member 40 is used to realize the electrical connection between the electrode tab and the electrode terminal, wherein the current collecting member 40 includes a first connecting portion 41 and a second connecting portion 42 which are insulated from each other, and the first connecting portion 41 is used to connect the positive electrode tab 21 and the positive terminal 31 to realize the electrical connection between the positive electrode tab 21 and the positive terminal 31. The second connecting portion 42 is used to connect the negative electrode tab 22 and the negative terminal 32 to realize the electrical connection between the negative electrode tab 22 and the negative terminal 32. Optionally, the positive electrode tab 21 is welded and fixed to the first connecting portion 41, and the negative electrode tab 22 is welded and fixed to the second connecting portion 42.

[0131] Compared with the solution in which the positive electrode tab 21 and the negative electrode tab 22 are electrically connected to the corresponding electrode terminals by means of different current collecting components 40, this design enables a single current collecting component 40 to simultaneously meet the electrical connection between the positive electrode tab 21 and the positive terminal 31, and the connection between the negative electrode tab 22 and the negative terminal 32, thereby reducing the overall size of the current collecting component 40 and reducing the occupation of the internal space of the shell 10 by the current collecting component 40, which helps to improve the corresponding energy density of the battery cell 500.

[0132] The first connection portion 41 has a first surface M1 facing the positive electrode tab 21, and the first surface M1 is the surface of the first connection portion 41 for contacting and connecting with the positive electrode tab 21. The second connection portion 42 has a second surface M2 facing the negative electrode tab 22, and the second surface M2 is the surface of the second connection portion 42 for contacting and connecting with the negative electrode tab 22.

[0133] On this basis, 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 needs of the first connecting portion 41 and the second connecting portion 42 relative to the positive electrode tab 21 and the negative electrode tab 22, the embodiment of the present application adjusts the structure of at least one of the first connecting portion 41 and the second connecting portion 42, so that the first surface M1 in the first connecting portion 41 is located on the side of the second surface M2 in the second connecting portion 42 away from the main body, so that the first connecting portion 41 and the second connecting portion 42 are respectively matched and connected with the tabs of different heights, thereby meeting the connection needs between the tabs and the current collecting component 40.

[0134] In some embodiments, see Figure 4 and Figure 8 The current collecting component 40 also includes an insulating portion 43 arranged 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, the second connecting portion 42 has a second connecting end D2 connected to the insulating portion 43, and the first connecting end D1 is located on a side of the second connecting end D2 away from the main body 23.

[0135] The insulating portion 43 is sandwiched between the first connecting portion 41 and the second connecting portion 42. The insulating portion 43 includes an insulating material to achieve mutual insulation between the first connecting portion 41 and the second connecting portion 42. The insulating portion 43 can have a variety of connection methods relative to the first connecting portion 41 and the second connecting portion 42, for example, it can be connected and fixed by welding and bonding.

[0136] In the embodiment of the present application, the first connection end D1 is an end structure on the first connection part 41 for connecting to the insulating part 43, and the second connection end D2 is an end structure on the second connection part 42 for connecting to the insulating part 43. Further, in order to enable the first connection part 41 to be adapted to contact with the positive electrode tab 21 and the second connection part 42 to be adapted to contact with the negative electrode tab 22, the embodiment of the present application sets the first connection end D1 on the side of the second connection end D2 away from the main body 23, that is, the end of the first connection part 41 connected to the insulating member is farther from the main body 23 than the end of the second connection part 42 connected to the insulating member, so that the first surface M1 is located on the side of the second surface M2 away from the main body 23, meeting the contact needs of the first surface M1 with the positive electrode tab 21 and the contact needs of the second surface M2 with the negative electrode tab 22.

[0137] In some embodiments, see Figure 6 and Fig. 9 The first connection 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, and the protrusion dimension of the first protrusion 412 relative to the first body portion 411 is L1. The second connection 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, and the protrusion dimension of the second protrusion 422 relative to the second body portion 421 is L2, and L2>L1.

[0138] The first body portion 411 is the main part of the first connection portion 41, the first protrusion 412 is connected to the first body portion 411 and protrudes in the direction close to the positive electrode tab 21, and the first protrusion 412 is a structure in the first connection portion 41 for connecting the positive electrode tab 21. Further, the first surface M1 is a surface of 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.

[0139] The second body portion 421 is the main part of the second connection portion 42, the second protrusion 422 is connected to the second body portion 421 and protrudes in the direction close to the negative electrode tab 22, and the second protrusion 422 is a structure in the second connection portion 42 for connecting the negative electrode tab 22. Further, the second surface M2 is a surface of 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.

[0140] In the embodiment of the present application, 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 corresponding to the first protrusion 412 and the second protrusion 422 are restricted, so that the protrusion dimension L1 of the first protrusion 412 relative to the first main body 411 is smaller than the protrusion dimension L2 of the second protrusion 422 relative to the second main body 421, that is, the second protrusion 422 protrudes closer to the main body relative to the first protrusion 412, so as to achieve contact connection between the first protrusion 412 and the positive electrode tab 21, and contact connection between the second protrusion 422 and the negative electrode tab 22, which has strong practicality.

[0141] It should be noted that, according to different actual needs, the first connection end D1 can be selected to be located on the side of the second connection end D2 away from the main body 23, and the protrusion dimension L1 of the first protrusion 412 is equal to the protrusion dimension L2 of the second protrusion 422. Alternatively, the first connection end D1 and the second connection end D2 can be selected to be arranged at the same height in the first direction X, and the protrusion dimension L1 of the first protrusion 412 is smaller than the protrusion dimension L2 of the second protrusion 422. Alternatively, the first connection end D1 can be selected to be located on the side of the second connection end D2 away from the main body 23, and the protrusion dimension L1 of the first protrusion 412 is smaller than the protrusion dimension L2 of the second protrusion 422. Of course, other methods can also be selected, as long as the first surface M1 is located on the side of the second surface M2 away from the main body 23.

[0142] In some embodiments, the battery cell 500 is a cylindrical battery cell 500 .

[0143] In the embodiment of the present application, considering that the cylindrical battery cell 500 may have a problem of poor welding, the negative electrode tab 22 in the cylindrical battery cell 500 is further compressed, so that 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, thereby reducing the density difference between the positive electrode tab 21 and the negative electrode tab 22, thereby improving the corresponding welding yield of the positive electrode tab 21 and the negative electrode tab 22, and improving the preparation reliability of the cylindrical battery cell 500.

[0144] In a second aspect, an embodiment of the present application provides a battery, the battery comprising a battery cell 500 in any of the aforementioned embodiments.

[0145] It should be noted that the battery provided in the embodiment of the present application has the beneficial effects of the battery cell 500 in any of the aforementioned embodiments. Please refer to the aforementioned description of the beneficial effects of the battery cell 500 for details, and the embodiment of the present application will not be repeated.

[0146] In a third aspect, an embodiment of the present application provides an electrical device, which includes a battery cell 500 in any of the aforementioned embodiments, and the battery cell 500 is used to provide electrical energy.

[0147] It should be noted that the electrical device provided in the embodiment of the present application has the beneficial effects of the battery cell 500 in any of the aforementioned embodiments. Please refer to the aforementioned description of the beneficial effects of the battery cell 500 for details, and the embodiment of the present application will not be repeated.

[0148] According to some embodiments of this application, please refer to Figures 4 to 6 The battery cell 500 includes a shell 10, an electrode assembly 20, a positive terminal 31, a negative terminal 32 and a current collecting member 40. The electrode assembly 20 is arranged in the shell 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 the 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.

[0149] The electrode assembly 20 includes a plurality of layer structures stacked along the second direction Y, and a plurality of second layer structures C2 stacked along the second direction Y, the first layer structure C1 and the second layer structure C2 are arranged at intervals, the plurality of first layer structures C1 are flattened or smoothed to form a positive electrode tab 21, the plurality of second layer structures C2 are flattened or smoothed to form a negative electrode tab 22, the first direction X intersects with the second direction Y, and the thickness of the first layer structure C1 is greater than the thickness of the second layer structure C2. The material of the positive electrode tab 21 includes metal aluminum, and the material of the negative electrode tab 22 includes metal copper.

[0150] The dimension of the positive electrode tab 21 in the first direction X is H1, and the dimension of the negative electrode tab 22 in the first direction X is H2, and 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.

[0151] 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 that are provided on the housing 10 and are 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 collecting member 40, and the current collecting member 40 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, and 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, and the first surface M1 is located on the side of the second surface M2 away from the main body 23.

[0152] 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 them; 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 replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, characterized in that: include: shell; an electrode assembly, disposed in the housing, the electrode assembly comprising a main body, a positive electrode tab and a negative electrode tab, the positive electrode tab and the negative electrode tab being located on the same side of the main body along a first direction, the first direction being the axial direction of the battery cell; A size of at least a portion of the positive electrode tab in the first direction is greater than a size of at least a portion of the negative electrode tab in the first direction.

2. The battery cell according to claim 1, characterized in that: 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, the first layer structures are spaced apart from the second layer structures, the plurality of first layer structures form the positive electrode tabs, the plurality of second layer structures form the negative electrode tabs, and the first direction intersects with the second direction; The thickness of the first layer structure is greater than the thickness of the second layer structure.

3. The battery cell according to claim 1, characterized in that: The material of the positive electrode tab includes metal aluminum, and the material of the negative electrode tab includes metal copper.

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

5. The battery cell according to claim 1, characterized in that: 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.

6. The battery cell according to claim 1, characterized in that: The battery cell further includes a positive terminal and a negative terminal which are arranged on the housing 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, characterized in that: Also included is a current collecting member, the current collecting member includes 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 are insulated from each other; The first connecting portion has a first surface facing the positive electrode tab, the second connecting portion has a second surface facing the negative electrode tab, and the first surface is located on a side of the second surface away from the main body.

8. The battery cell according to claim 7, characterized in that: The current collecting member further includes an insulating portion disposed between the first connecting portion and the second connecting portion, the first connecting portion having a first connecting end connected to the insulating portion, and the second connecting portion having a second connecting end connected to the insulating portion; The first connection end is located at a side of the second connection end away from the main body.

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

10. The battery cell according to claim 1, characterized in that: The battery cell is a cylindrical battery cell.

11. A battery, characterized in that: The invention comprises a battery cell as claimed in any one of claims 1 to 10.

12. An electrical device, characterized in that: The invention comprises a battery cell according to any one of claims 1 to 10, wherein the battery cell is used to provide electrical energy.

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