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 a first protective layer, the shell comprises a shell body and an end cover, the shell body is provided with an opening, the end cover covers the opening, and the end cover is welded to the shell body and forms a first welding part. The first protective layer covers the surface of the first welding part. By arranging the first protection layer, the first protection layer covers the surface of the first welding part, so that the risk that the first welding part is rusted or damaged is reduced, and the reliability of the battery monomer can be effectively 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] With the development of new energy technology, batteries are used more and more widely, for example, in mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes and electric tools, etc.

[0003] In a battery cell, the shell is an important component of the battery cell and is crucial to the stable and reliable operation of the battery cell. The reliability of the shell directly affects the quality of the battery cell. Therefore, the reliability of the shell is a key research object 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 effectively improve the reliability of the battery cell.

[0005] In a first aspect, an embodiment of the present application provides a battery cell, the battery cell comprises an outer shell and a first protective layer, the outer shell comprises a shell and an end cover, the shell has an opening, the end cover covers the opening, the end cover is welded to the shell and forms a first welding portion, and the first protective layer covers the surface of the first welding portion.

[0006] The above technical solution provides a first protective layer, which covers the surface of the first welding portion, thereby reducing the risk of rust or damage to the first welding portion, thereby effectively improving the reliability of the battery cell.

[0007] In some embodiments of the first aspect, the first protective layer includes a first connecting segment, a main segment, and a second connecting segment connected to each other, wherein the main segment is located between the first connecting segment and the second connecting segment. The first connecting segment is connected to the shell, the second connecting segment is connected to the end cover, and the main segment covers the surface of the first welding portion.

[0008] On the one hand, it can further improve the coverage effect of the first protective layer on the first welding part and reduce the risk of coverage dead corners; on the other hand, the first connecting part and the second connecting part can also improve the connection firmness of the first protective layer and reduce the risk of the first protective layer falling off.

[0009] In some embodiments of the first aspect, the battery cell further comprises an electrode assembly, which is contained in a housing. The housing comprises a side wall surrounding the electrode assembly, the first connecting section is connected to a side of the side wall facing away from the electrode assembly, and the second connecting section is connected to a side of the end cap facing away from the electrode assembly.

[0010] The above technical solution is easy to operate, has low difficulty, and is conducive to reducing costs by welding the end cover and the shell body outside the shell and setting the first protective layer.

[0011] In some embodiments of the first aspect, the battery cell further includes an insulating member connected to a side of the side wall facing away from the electrode assembly.

[0012] The insulating member can insulate the outer shell, reduce the risk of short circuit between the battery cell and external electrical connection components, and thus improve the reliability of the battery cell.

[0013] In some embodiments of the first aspect, the first connecting section and the insulating member are spaced apart, the structural design is simple, and the preparation difficulty is relatively low, which is conducive to reducing costs and improving product yield.

[0014] In some embodiments of the first aspect, the first connecting section is connected to the insulating member along a side edge portion of the first connecting section away from the main body section along its own extending direction.

[0015] On the one hand, the first connecting section and the insulating member both have a protective effect on the shell, which can improve the reliability of the shell; on the other hand, the consistency of the outer surface of the shell can be effectively improved, which is beneficial to improving the appearance of the battery cell.

[0016] In some embodiments of the first aspect, along the thickness direction of the side wall, the surface of the first connection section facing away from the side wall is flush with the surface of the insulating member facing away from the side wall, which can effectively improve the flatness of the outer surface of the housing, thereby further improving the appearance of the battery cell.

[0017] In some embodiments of the first aspect, along a thickness direction of the side wall, the first connecting segment and the insulating member are at least partially overlapped.

[0018] The above technical solution can further improve the coverage effect of the first connecting section and the insulating member on the side wall, reduce the risk of covering dead corners, thereby further improving the protection effect of the first connecting section and the insulating member on the shell, which is beneficial to improving the reliability of the shell.

[0019] In some embodiments of the first aspect, the first protective layer and the insulating member are an integrally formed structure.

[0020] On the one hand, there is no need to connect the first protective layer and the insulating member through an additional connection process, which simplifies the manufacturing process. At the same time, compared with connecting the first protective layer and the insulating member through an additional connection process, the first protective layer and the insulating member in an integrated structure have a higher connection firmness.

[0021] In some embodiments of the first aspect, the side wall is provided with a recessed portion, which is recessed relative to the outer surface of the side wall, and the bottom wall of the recessed portion is welded to the end cover to form a first welding portion, and at least a portion of the first connecting section is accommodated in the recessed portion.

[0022] The above technical solution can reduce the size of the first welding portion and the first connecting section protruding from the housing, thereby reducing the overall volume of the battery cell, which is beneficial to improving the energy density of the battery cell.

[0023] In some embodiments of the first aspect, along the thickness direction of the side wall, a surface of the first connecting section facing away from the electrode assembly is flush with a surface of the side wall facing away from the electrode assembly, which can improve the flatness of the outer surface of the side wall and optimize the appearance of the product.

[0024] In some embodiments of the first aspect, along the thickness direction of the end cap, a surface of the second connecting section facing away from the electrode assembly is flush with a surface of the end cap facing away from the electrode assembly, which can improve the flatness of the outer surface of the end cap, thereby further optimizing the appearance of the product.

[0025] In some embodiments of the first aspect, a minimum distance L1 between a side edge of the first connecting section away from the main section along its own extension direction and the first welding portion satisfies the relationship: L1≥0.05mm. A minimum distance L2 between a side edge of the second connecting section away from the main section along its own extension direction and the first welding portion satisfies the relationship: L2≥0.05mm.

[0026] The above technical solution can further improve the coverage effect of the first protective layer on the first welding part and reduce the risk of coverage dead corners by setting the minimum distance L1 between the first connecting section along its own extension direction away from the main section and the first welding part and the minimum distance L2 between the second connecting section along its own extension direction away from the main section and the first welding part within the above range, thereby further improving the reliability of the battery cell.

[0027] In some embodiments of the first aspect, the minimum distance L1 satisfies the relationship: L1 ≥ 0.1 mm, and the minimum distance L2 satisfies the relationship: L2 ≥ 0.1 mm, so as to further reduce the risk of a coverage blind spot.

[0028] In some embodiments of the first aspect, a plating layer is disposed on the housing, the plating layer surrounds the first welding portion, and the first protective layer is connected to the plating layer.

[0029] The above technical solution provides a coating on the shell, and the coating can protect the surface of the shell, thereby further improving the reliability of the shell as a whole.

[0030] In some embodiments of the first aspect, the thickness d1 of the coating satisfies the relationship: 0.1 μm≤d1≤10 μm. By setting the thickness d1 of the coating within the above range, the reliability of the entire housing can be improved while reducing the influence of the coating on the overall size of the battery cell.

[0031] In some embodiments of the first aspect, the thickness d1 of the coating satisfies the relationship: 0.5 μm≤d1≤5 μm, so as to further take into account the reliability of the entire housing and the overall size of the battery cell.

[0032] In some embodiments of the first aspect, the first welding portion includes a transition surface connected to an outer surface of the shell and an outer surface of the end cover.

[0033] By setting the transition surface, a smooth transition can be achieved between the surface of the first welding portion and the outer surface of the shell, and a smooth transition can be achieved between the surface of the first welding portion and the outer surface of the end cover. On the one hand, the difficulty of setting the first protective layer can be reduced; on the other hand, the overall surface smoothness of the battery cell can be improved, which is beneficial to improving the quality of the battery cell.

[0034] In some embodiments of the first aspect, the transition surface is an arc surface.

[0035] The above technical solution can reduce the difficulty of welding the end cover and the shell while reducing the difficulty of preparing the first protective layer by setting the surface of the first welding part as an arc surface, and can effectively improve the product yield.

[0036] In some embodiments of the first aspect, the radian R of the arc surface satisfies the relationship: R ≥

[0037] 100μm.

[0038] The above technical solution can further reduce the difficulty of preparing the first protective layer and improve the product yield by setting the curvature R of the arc surface to satisfy the above relationship.

[0039] In some embodiments of the first aspect, the curvature R satisfies the relationship: R ≥ 200 μm.

[0040] In some embodiments of the first aspect, the thickness d2 of the first protective layer satisfies the relationship: d2 ≥ 5 μm. By setting the thickness d2 of the first protective layer to satisfy the above relationship, the protective effect of the first protective layer on the first welding portion can be further improved.

[0041] In some embodiments of the first aspect, a thickness d2 of the first protective layer satisfies the relationship: d2 ≥ 10 μm.

[0042] In some embodiments of the first aspect, the first protective layer is a transparent structure, which can further optimize the appearance of the product.

[0043] In some embodiments of the first aspect, the first protective layer includes a fluorescent element, which can further improve the accuracy of detecting the thickness of the first protective layer.

[0044] In some embodiments of the first aspect, the first protective layer includes a coating material, and the coating material includes polyacrylate, polyurethane, or epoxy resin.

[0045] The above technical solution uses a coating material to be coated on the first welding portion through a coating process to form a first protective layer. The process is simple, which is conducive to reducing the difficulty of preparing the first protective layer and reducing costs.

[0046] In some embodiments of the first aspect, the viscosity η of the coating material satisfies the relationship: 1 cps≤η≤2000 cps. By setting the viscosity η of the coating material within the above range, the coating quality can be effectively improved and the product yield can be increased.

[0047] In some embodiments of the first aspect, the viscosity η of the coating material satisfies the relationship: 1 cps≤η≤1000 cps, so as to further improve the coating quality and product yield.

[0048] In some embodiments of the first aspect, the adhesion between the first protective layer and the first welding portion ranges from level 0 to level 1.

[0049] By setting the adhesion between the first protective layer and the first welding portion to satisfy the above relationship, the reliability of the connection between the first protective layer and the first welding portion can be further improved, and the risk of the first protective layer falling off can be reduced.

[0050] In some embodiments of the first aspect, a second welding portion is further provided on the end cover, and the second welding portion is electrically connected to the electrode assembly of the battery cell. The battery cell also includes a second protective layer, and the second protective layer covers the surface of the second welding portion.

[0051] The above technical solution can isolate the second welding part from the external environment, thereby isolating water vapor and reducing the risk of rusting of the second welding part. In addition, the second protective layer itself has a certain hardness, thereby reducing the risk of scratches or collisions of the second welding part, thereby further improving the reliability of the battery cell.

[0052] In some embodiments of the first aspect, the first protective layer and the second protective layer are an integrally formed structure.

[0053] On the one hand, there is no need to connect the first protective layer and the second protective layer through an additional connection process, which simplifies the manufacturing process. At the same time, compared with connecting the first protective layer and the second protective layer through an additional connection process, the first protective layer and the second protective layer in an integrated structure have a higher connection firmness.

[0054] In some embodiments of the first aspect, the battery cell is a cylindrical battery cell.

[0055] In a second aspect, the present application provides a battery, which includes a battery cell provided by any embodiment of the first aspect.

[0056] In a third aspect, the present application provides an electrical device, comprising a battery cell provided by any embodiment of the first aspect, wherein the battery cell is used to provide electrical energy.

[0057] 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

[0058] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0059] Figure 1 A schematic diagram of the structure of a vehicle provided in some embodiments of the present application;

[0060] Figure 2 A schematic diagram of an exploded structure of a battery provided in some embodiments of the present application;

[0061] Figure 3 A schematic cross-sectional structure diagram of a battery cell provided in some embodiments of the present application;

[0062] Figure 4 A schematic cross-sectional structure diagram of a shell of a battery cell provided in some embodiments of the present application;

[0063] Figure 5 for Figure 3 A local enlarged structural schematic diagram of A;

[0064] Figure 6 A schematic cross-sectional structure diagram of another battery cell provided in some embodiments of the present application;

[0065] Figure 7 for Figure 6 A schematic diagram of the local enlarged structure at B;

[0066] Figure 8 A schematic cross-sectional structure diagram of another battery cell provided in some embodiments of the present application;

[0067] Fig. 9 for Figure 8 A schematic diagram of the local enlarged structure at C;

[0068] Fig.10 A schematic cross-sectional structure diagram of another battery cell provided in some embodiments of the present application;

[0069] Fig.11 for Fig.10 A schematic diagram of the local enlarged structure at D;

[0070] Fig.12 A schematic cross-sectional structure diagram of another battery cell provided in some embodiments of the present application;

[0071] Fig.13 for Fig.12 Schematic diagram of the local enlarged structure at E.

[0072] The reference numerals in the specific implementation manner are as follows:

[0073] 1. Vehicle; 2. Battery; 3. Controller; 4. Motor; 5. Box; 7. Battery cell;

[0074] 10. Shell; 11. Shell; 111. Opening; 112. Side wall; 1121. Recess; 12. End cap; 121. Second welding portion; 13. First welding portion; 131. Transition surface; 14. Plating; 20. First protective layer; 21. First connecting section; 22. Main section; 23. Second connecting section; 30. Electrode assembly; 40. Insulator; 50. Second protective layer; 60. Current collector. DETAILED DESCRIPTION

[0075] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0076] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0077] Reference to "embodiment" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0078] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0079] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0080] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0081] The term "plurality" used in the present application refers to two or more (including two).

[0082] In the present application, the term "parallel" includes not only the absolutely parallel situation, but also the roughly parallel situation conventionally recognized in engineering; meanwhile, "vertical" includes not only the absolutely vertical situation, but also the roughly vertical situation conventionally recognized in engineering.

[0083] In the present application, the battery cell may include a lithium-ion secondary battery cell, a lithium-ion primary battery cell, a lithium-sulfur battery cell, a sodium-lithium-ion battery cell, a sodium-ion battery cell or a magnesium-ion battery cell, etc., and the embodiments of the present application do not limit this. The battery cell may be cylindrical, flat, rectangular or other shapes, etc., and the embodiments of the present application do not limit this.

[0084] The battery mentioned in the embodiments of the present application may include one or more battery cells to provide a single physical module with higher voltage and capacity. When there are multiple battery cells, the multiple battery cells are connected in series, in parallel or in mixed connection through a busbar component.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] In some embodiments, the battery may be an energy storage device, which includes an energy storage container, an energy storage cabinet, and the like.

[0089] 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 between the positive electrode and the negative electrode. The separator is set between the positive electrode and the negative electrode to prevent the positive and negative electrodes from short-circuiting, while allowing active ions to pass through.

[0090] 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.

[0091] 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.

[0092] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, silver surface treated stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. may be used. The composite current collector may include a polymer material base 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 polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0093] 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 conventional 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.

[0094] In some embodiments, the positive electrode may be carbon foam or metal foam. The metal foam may be nickel foam, copper foam, aluminum foam or alloy foam. When the metal foam is used as the positive electrode, the positive electrode active material may not be provided on the surface of the metal foam, but the positive electrode active material may also be provided. As an example, lithium source material, potassium metal or sodium metal may be filled or / and deposited in the metal foam, and the lithium source material is lithium metal and / or lithium-rich material.

[0095] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0096] As an example, the negative electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium with silver surface treatment 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 (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0097] 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.

[0098] 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.

[0099] 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.

[0100] In some embodiments, the negative electrode may be foamed carbon or foamed metal. The foamed metal may be foamed nickel, foamed copper, foamed aluminum or foamed alloy, etc. When the foamed metal is used as the negative electrode sheet, the surface of the foamed metal may not be provided with a negative electrode active material, but of course, a negative electrode active material may also be provided.

[0101] As an example, a lithium source material, potassium metal or sodium metal may be filled or / and deposited in the negative electrode current collector, and the lithium source material is lithium metal and / or lithium-rich material.

[0102] 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.

[0103] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0104] In some embodiments, the separator is a separator membrane, which can be any known porous separator membrane with good chemical stability and mechanical stability.

[0105] 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.

[0106] 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.

[0107] In some embodiments, the battery cell further includes an electrolyte, which plays a role in conducting ions between the positive and negative electrodes. The electrolyte may be in a liquid, gel or solid state.

[0108] 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.

[0109] In some embodiments, the electrode assembly is a laminate structure.

[0110] As an example, a plurality of positive electrode sheets and a plurality of negative electrode sheets may be provided respectively, and the plurality of positive electrode sheets and the plurality of negative electrode sheets may be alternately stacked.

[0111] As an example, a plurality of positive electrode sheets may be provided, and the negative electrode sheet may be folded to form a plurality of stacked folded segments, with a positive electrode sheet being sandwiched between adjacent folded segments.

[0112] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of folded sections that are stacked.

[0113] As an example, a plurality of separators may be provided, each of which is provided between any adjacent positive electrode sheets or negative electrode sheets.

[0114] As an example, the separator may be disposed continuously, and may be disposed between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0115] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0116] 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.

[0117] With the development of new energy technology, batteries are used more and more widely, for example, in mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes and electric tools, etc.

[0118] In a battery cell, the shell is an important component of the battery cell and is crucial to the stable and reliable operation of the battery cell. The reliability of the shell directly affects the quality of the battery cell. At present, the shell and the end cover are usually welded to form the shell. The reliability of the welding area between the shell and the end cover is weak. During the transportation, storage and practical use of the battery cell, the welding area is prone to rust or damage, thereby affecting the reliability of the battery cell.

[0119] Based on the above considerations, the present application designs a battery cell, which includes an outer shell and a first protective layer, wherein the outer shell includes a shell and an end cover, wherein the shell has an opening, the end cover covers the opening, the end cover is welded to the shell and forms a first welding portion, and the first protective layer covers the surface of the first welding portion. In this way, the first protective layer can protect the first welding portion, reduce the risk of rust or damage to the first welding portion, and thus effectively improve the reliability of the battery cell.

[0120] The technical solutions described in the embodiments of the present application are applicable to batteries and electrical devices using batteries.

[0121] Electrical devices may be, but are not limited to, vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and electric tools, etc. Vehicles may be, but are not limited to, fuel vehicles, gas vehicles, or new energy vehicles, and new energy vehicles may be, but are not limited to, pure electric vehicles, hybrid vehicles, or extended-range vehicles, etc.; spacecraft include, but are not limited to, airplanes, rockets, space shuttles, and spacecraft, etc.; electric toys include, but are not limited to, fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc.; electric tools include, but are not limited to, metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc.

[0122] It should be understood that the technical solutions described in the embodiments of the present application are not limited to the batteries and electrical equipment described above, but can also be applied to all batteries including battery boxes and electrical equipment using batteries. However, for the sake of simplicity, the following embodiments are described using electric vehicles as examples.

[0123] Figure 1 A schematic diagram of the structure of a vehicle provided for some embodiments of the present application.

[0124] Continue to refer Figure 1 The vehicle 1 is provided with a battery 2 inside, and the battery 2 can be provided at the bottom, head, or tail of the vehicle 1. The battery 2 can be used for powering the vehicle 1, for example, the battery 2 can be used as an operating power source for the vehicle 1.

[0125] The vehicle 1 may further include a controller 3 and a motor 4 , wherein the controller 3 is used to control the battery 2 to supply power to the motor 4 , for example, to meet the power requirements of starting, navigating, and driving the vehicle 1 .

[0126] In some embodiments of the present application, the battery 2 can not only serve as an operating power source for the vehicle 1, but also serve as a driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0127] Figure 2 An exploded schematic diagram of a battery provided for some embodiments of the present application.

[0128] Continue to refer Figure 2 The battery 2 includes a box body 5 and a battery cell 7 , and the battery cell 7 is accommodated in the box body 5 .

[0129] The box body 5 is used to accommodate the battery cells, and the box body 5 can be of various structures, such as a cylinder, a cuboid, etc.

[0130] In the battery 2, the battery cell 7 can be one or more. If there are more than one battery cell 7, the battery cells 7 can be connected in series, in parallel or in mixed connection. Mixed connection means that the battery cells 7 are both connected in series and in parallel. The battery cells 7 can be directly connected in series, in parallel or in mixed connection, and then the whole body formed by the battery cells 7 can be accommodated in the box 5; of course, the battery cells 7 can also be connected in series, in parallel or in mixed connection to form a battery module, and then the battery modules can be connected in series, in parallel or in mixed connection to form a whole body, and then accommodated in the box 5.

[0131] Figure 3 A schematic cross-sectional structure diagram of a battery cell provided in some embodiments of the present application, Figure 4 A schematic cross-sectional structure diagram of a battery cell housing provided in some embodiments of the present application, Figure 5 for Figure 3 Schematic diagram of the local enlarged structure at A.

[0132] Continue to refer Figures 3 to 5 The embodiment of the present application provides a battery cell 7, which includes an outer shell 10 and a first protective layer 20. The outer shell 10 includes a shell body 11 and an end cover 12. The shell body 11 has an opening 111. The end cover 12 covers the opening 111. The end cover 12 is welded to the shell body 11 and forms a first welding portion 13. The first protective layer 20 covers the surface of the first welding portion 13.

[0133] The housing 11 is a component used to cooperate with the end cover 12 to form an internal environment of the battery cell 7, wherein the formed internal environment can be used to accommodate the electrode assembly 30, electrolyte and other components.

[0134] Optionally, the shell 11 may be in various shapes and sizes, such as but not limited to a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. The shape of the shell 11 may be determined according to the specific shape and size of the electrode assembly 30 .

[0135] Optionally, the material of the housing 11 may be but is not limited to copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0136] The end cover 12 refers to a component that covers the opening 111 of the housing 11 to isolate the internal environment of the battery cell 7 from the external environment. The shape of the end cover 12 can be adapted to the shape of the housing 11 to match the housing 11 .

[0137] Optionally, the end cap 12 can be made of a material with a certain hardness and strength, which can be but not limited to copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. In this way, the end cap 12 is not easily deformed when squeezed and collided, so that the battery cell 7 can have a higher structural strength and reliability can also be improved. As an example, the end cap 12 and the housing 11 can be made of the same material to simplify the preparation process and help reduce costs.

[0138] As an example, functional components such as electrode terminals may be provided on the end cover 12 , and the electrode terminals may be used to be electrically connected to the electrode assembly 30 for outputting or inputting electrical energy of the battery cell 7 .

[0139] As an example, the end cover 12 may also be provided with a pressure relief mechanism for releasing the internal pressure when the internal pressure or temperature of the battery cell 7 reaches a threshold value.

[0140] As an example, an insulating member may be provided inside the end cap 12, and the insulating member may be used to isolate the electrical connection components in the housing 11 from the end cap 12 to reduce the risk of short circuit. Optionally, the insulating member may be plastic, rubber, or the like.

[0141] Exemplarily, the end cap 12 is connected to the shell 11 by welding, and a first connection portion is formed at the connection between the end cap 12 and the shell 11. The first protective layer 20 covers the surface of the first welding portion 13 to isolate the first welding portion 13 from the external environment, thereby isolating water vapor and reducing the risk of rusting of the first welding portion 13. In addition, the first protective layer 20 itself has a certain hardness, thereby reducing the risk of scratches or bruises on the first welding portion 13.

[0142] Optionally, the first welding portion 13 may be located inside the outer shell 10, which is beneficial to improving the appearance of the battery cell 7; the first welding portion 13 may also be located outside the outer shell 10, which is convenient for welding operations and is beneficial to reducing the difficulty of welding. As an example, in the case where the first welding portion 13 is located inside the outer shell 10, a welding hole may be provided on the end cover 12, and the welding hole penetrates the end cover 12 along the thickness direction of the end cover 12. After the end cover 12 covers the opening 111 of the shell 11, the welding gun can weld the end cover 12 and the shell 11 inside the outer shell 10 through the welding hole; in the case where the first welding portion 13 is located outside the outer shell 10, the welding gun directly welds the end cover 12 and the shell 11 outside the outer shell 10.

[0143] Optionally, the first welding portion 13 may be located inside the outer shell 10, which is beneficial to improving the appearance of the battery cell 7; the first welding portion 13 may also be located outside the outer shell 10, which is convenient for welding operations and is beneficial to reducing the difficulty of welding. As an example, in the case where the first welding portion 13 is located inside the outer shell 10, a welding hole may be provided on the end cover 12, and the welding hole penetrates the end cover 12 along the thickness direction of the end cover 12. After the end cover 12 covers the opening 111 of the shell 11, the welding gun can weld the end cover 12 and the shell 11 inside the outer shell 10 through the welding hole; in the case where the first welding portion 13 is located outside the outer shell 10, the welding gun directly welds the end cover 12 and the shell 11 outside the outer shell 10.

[0144] Optionally, the first protective layer 20 may be directly connected to the first welding portion 13, or may be restricted on the first welding portion 13 by other components. As an example, the connection between the first protective layer 20 and the first welding portion 13 may be, but is not limited to, bonding, riveting, or bolting.

[0145] Optionally, the first protective layer 20 may be but is not limited to being made of metal or non-metal materials. For example, the metal material may be copper, aluminum or stainless steel, etc.; the non-metal material may be acrylate, polyurethane, epoxy resin, polyethylene, polypropylene or polyvinyl chloride, etc.

[0146] The above technical solution provides the first protective layer 20 , and the first protective layer 20 covers the surface of the first welding portion 13 , thereby reducing the risk of rust or damage to the first welding portion 13 , thereby effectively improving the reliability of the battery cell 7 .

[0147] In some optional embodiments, the battery cell 7 may be, but is not limited to, a cylindrical battery cell 7 or a square battery cell 7 .

[0148] In some embodiments, the first protective layer 20 includes a first connecting segment 21, a main segment 22, and a second connecting segment 23, wherein the main segment 22 is located between the first connecting segment 21 and the second connecting segment 23. The first connecting segment 21 is connected to the housing 11, the second connecting segment 23 is connected to the end cover 12, and the main segment 22 covers the surface of the first welding portion 13.

[0149] Exemplarily, the first connection section 21 extends from the main section 22 in a direction close to the shell 11 and is connected to the shell 11, and the second connection section 23 extends from the main section 22 in a direction close to the end cover 12 and is connected to the end cover 12. On the one hand, the covering effect of the first protective layer 20 on the first welding portion 13 can be further improved, reducing the risk of covering dead angles; on the other hand, the first connection portion and the second connection portion can also improve the connection firmness of the first protective layer 20 and reduce the risk of the first protective layer 20 falling off.

[0150] Optionally, the first connection section 21 may be directly connected to the housing 11, or may be restricted to the housing 11 through other components. As an example, the connection between the first connection section 21 and the housing 11 may be, but is not limited to, bonding, riveting, or bolting.

[0151] Optionally, the second connection section 23 may be directly connected to the end cover 12, or may be restricted to the end cover 12 by other components. As an example, the connection between the second connection section 23 and the end cover 12 may be, but is not limited to, bonding, riveting, or bolting.

[0152] In some embodiments, the battery cell 7 further includes an electrode assembly 30, which is contained in the housing 10. The housing 11 includes a side wall 112 surrounding the electrode assembly 30, the first connecting section 21 is connected to a side of the side wall 112 facing away from the electrode assembly 30, and the second connecting section 23 is connected to a side of the end cap 12 facing away from the electrode assembly 30.

[0153] The electrode assembly 30 is a component in the battery cell 7 where electrochemical reactions occur. One or more electrode assemblies 30 may be included in the housing 10. The electrode assembly 30 is mainly formed by winding or stacking positive and negative electrode sheets, and a separator is usually provided between the positive and negative electrode sheets. The parts of the positive and negative electrode sheets with active materials constitute the main body of the electrode assembly 30, and the parts of the positive and negative electrode sheets without active materials each constitute a tab. The positive tab and the negative tab may be located together at one end of the main body or respectively at both ends of the main body. During the charge and discharge process of the battery, the positive active material and the negative active material react with the electrolyte, and the tabs connect the electrode terminals to form a current loop.

[0154] Exemplarily, the first welding portion 13 is located outside the housing 10, the first connecting section 21 extends from the main section 22 in a direction close to the housing 11 and is connected to the side of the side wall 112 facing away from the electrode assembly 30, and the second connecting section 23 extends from the main section 22 in a direction close to the end cap 12 and is connected to the side of the end cap 12 facing away from the electrode assembly 30. Welding the end cap 12 and the housing 11 and setting the first protective layer 20 from the outside of the housing 10 is easy to operate, has low difficulty, and is conducive to reducing costs.

[0155] In some embodiments, the battery cell 7 further includes an insulating member 40 , which is connected to a side of the side wall 112 facing away from the electrode assembly 30 .

[0156] Exemplarily, the insulating member 40 can insulate the housing 10 , reducing the risk of short circuit between the battery cell 7 and external electrical connection components, thereby improving the reliability of the battery cell 7 .

[0157] Optionally, the insulating member 40 may be directly connected to the side wall 112, or may be restricted on the side wall 112 by other components. As an example, the connection between the insulating member 40 and the side wall 112 may be, but is not limited to, bonding, riveting, or bolting.

[0158] Optionally, the insulating member 40 may be, but is not limited to, a film layer structure, a sheet structure, or a block structure.

[0159] Optionally, the insulating member 40 may be made of, but not limited to, polypropylene, polyethylene, or polybutylene, etc. The insulating member 40 may also include a flame retardant, an antioxidant, etc., to improve the performance of the insulating member 40 .

[0160] In some embodiments, the first connecting section 21 is spaced apart from the insulating member 40 .

[0161] For example, along the direction of the plane where the side wall 112 is located, there is a certain distance between the first connection portion and the insulating member 40. In other words, the first protective layer 20 and the insulating member 40 are independent and not connected to each other. With such a configuration, the structural design is simple, the manufacturing difficulty is low, and it is conducive to reducing costs and improving product yield.

[0162] In some embodiments, the first connecting section 21 is connected to the insulating member 40 along a side edge of the first connecting section 21 that is away from the main section 22 along its own extending direction.

[0163] Exemplarily, the first connection section 21 is spliced ​​with the insulating member 40. In other words, the first connection section 21 and the insulating member 40 together cover the outer surface of the side wall 112 along the thickness direction of the side wall 112. On the one hand, the first connection section 21 and the insulating member 40 both have a protective effect on the shell 11, which can improve the reliability of the shell 11; on the other hand, the consistency of the outer surface of the shell 10 can be effectively improved, which is conducive to improving the appearance of the battery cell 7.

[0164] In some embodiments, along the thickness direction of the side wall 112 , a surface of the first connecting section 21 facing away from the side wall 112 is flush with a surface of the insulating member 40 facing away from the side wall 112 .

[0165] Exemplarily, a surface of the first connecting section 21 facing away from the side wall 112 and a surface of the insulating member 40 facing away from the side wall 112 are located on the same plane, which can effectively improve the flatness of the outer surface of the housing 10 and further improve the appearance of the battery cell 7.

[0166] Figure 6 This is a schematic cross-sectional structure diagram of another battery cell 7 provided in some embodiments of the present application. Figure 7 for Figure 6 A schematic diagram of the local enlarged structure at B. Figure 8for Figure 6 A schematic diagram of the partial enlarged structure before the end cover 12 and the shell 11 are welded at B.

[0167] Continue to refer Figures 6 to 8 In some embodiments, along the thickness direction of the side wall 112 , the first connecting section 21 and the insulating member 40 are at least partially overlapped.

[0168] Exemplarily, the first connecting section 21 and the insulating member 40 jointly cover the outer surface of the side wall 112 along the thickness direction of the side wall 112, and there is an overlap between the first connecting section 21 and the insulating member 40, which can further improve the covering effect of the first connecting section 21 and the insulating member 40 on the side wall 112 and reduce the risk of covering dead corners, thereby further improving the protective effect of the first connecting section 21 and the insulating member 40 on the shell 11, which is beneficial to improving the reliability of the shell 11.

[0169] Figure 8 A schematic cross-sectional structure diagram of another battery cell provided in some embodiments of the present application is shown in FIG. Fig. 9 for Figure 8 Schematic diagram of the local enlarged structure at C.

[0170] Continue to refer Figure 8 and Fig. 9 In some embodiments, the first protective layer 20 and the insulating member 40 are an integrally formed structure.

[0171] For example, a structure having insulating properties may be provided in the first protective layer 20 , or the first protective layer 20 may be provided with a double-layer structure, wherein one layer is a protective layer of the first welding portion 13 , and the other layer is an insulating layer.

[0172] Thus, on the one hand, there is no need to connect the first protective layer 20 and the insulating member 40 through an additional connection process, which simplifies the manufacturing process. At the same time, compared with connecting the first protective layer 20 and the insulating member 40 through an additional connection process, the first protective layer 20 and the insulating member 40 in an integrated structure have a higher connection firmness.

[0173] Continue to refer Figure 6 to Figure 7 In some embodiments, the side wall 112 is provided with a recess 1121, which is recessed relative to the outer surface of the side wall 112. The bottom wall of the recess 1121 is welded to the end cover 12 to form a first welding portion 13, and at least a portion of the first connecting section 21 is accommodated in the recess 1121.

[0174] Exemplarily, the recess 1121 can be formed by the outer surface of the side wall 112 being recessed along the thickness direction of the side wall 112. After the end cover 12 is welded to the bottom wall of the recess 1121, the recess 1121 can provide an accommodation space so that the first welding portion 13 can be accommodated in the recess 1121, and after the first connecting section 21 covers the first welding portion 13, at least part of the first connecting section 21 is accommodated in the recess 1121, which can reduce the size of the first welding portion 13 and the first connecting section 21 protruding from the outer shell 10, thereby reducing the overall volume of the battery cell 7, which is beneficial to improving the energy density of the battery cell 7.

[0175] Optionally, the first connecting section 21 may be partially accommodated in the recess 1121 , or the first connecting section 21 may be fully accommodated in the recess 1121 .

[0176] Optionally, the recess 1121 and the side wall 112 may be an integrally formed structure, which can simplify the manufacturing process and help reduce costs.

[0177] In some embodiments, along the thickness direction of the side wall 112, the side surface of the first connecting section 21 facing away from the electrode assembly 30 is flush with the side surface of the side wall 112 facing away from the electrode assembly 30, which can improve the flatness of the outer surface of the side wall 112 and optimize the appearance of the product.

[0178] In some embodiments, along the thickness direction of the end cover 12 , a surface of the second connecting segment 23 facing away from the electrode assembly 30 is flush with a surface of the end cover 12 facing away from the electrode assembly 30 .

[0179] Exemplarily, the recess 1121 can provide an accommodating space. During the welding process between the end cover 12 and the bottom wall of the recess 1121, the material at the connection between the end cover 12 and the bottom wall of the recess 1121 will melt first, and the melted fluid will flow toward the recess 1121. After the melted fluid solidifies to form the first welding portion 13, there will be a certain distance between the first welding portion 13 and the side surface of the end cover 12 facing away from the electrode assembly 30.

[0180] In this way, after the above technical solution covers the first protective layer 20 on the first welding portion 13, the flatness of the outer surface of the end cover 12 can be improved by making the side surface of the second connecting section 23 facing away from the electrode assembly 30 flush with the side surface of the end cover 12 facing away from the electrode assembly 30, thereby further optimizing the appearance of the product.

[0181] In some embodiments, a minimum distance L1 between a side edge of the first connecting section 21 away from the main section 22 along its extension direction and the first welding portion 13 satisfies the relationship: L1 ≥ 0.05 mm.

[0182] Exemplarily, the minimum distance between a side edge of the first connecting section 21 away from the main section 22 along its extension direction and the first welding portion 13 can be understood as the size of the outer edge of the first connecting section 21 exceeding the edge of the first welding portion 13 .

[0183] As an example, the minimum distance L1 may be, but is not limited to, 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, etc.

[0184] The above technical solution can further improve the coverage effect of the first protective layer 20 on the first welding portion 13 by setting the minimum distance L1 between the side edge of the first connecting section 21 away from the main section 22 along its own extension direction within the above range, reduce the risk of coverage dead corners, and thus further improve the reliability of the battery cell 7.

[0185] Furthermore, a minimum distance L1 between a side edge of the first connecting section 21 away from the main section 22 along its extension direction and the first welding portion 13 satisfies the relationship: L1 ≥ 0.1 mm, so as to further reduce the risk of a coverage blind spot.

[0186] As an example, the minimum distance L1 may be, but is not limited to, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, etc.

[0187] In some embodiments, a minimum distance L2 between a side edge of the second connecting section 23 away from the main section 22 along its own extension direction and the first welding portion 13 satisfies the relationship: L2 ≥ 0.05 mm.

[0188] Exemplarily, the minimum distance between a side edge of the second connecting section 23 away from the main section 22 along its extension direction and the first welding portion 13 can be understood as the size of the outer edge of the second connecting section 23 exceeding the edge of the first welding portion 13 .

[0189] As an example, the minimum distance L2 may be, but is not limited to, 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, etc.

[0190] The above technical solution can further improve the coverage effect of the first protective layer 20 on the first welding portion 13 by setting the minimum distance L2 between the side edge of the second connecting section 23 away from the main section 22 along its own extension direction within the above range, reduce the risk of coverage dead corners, and thus further improve the reliability of the battery cell 7.

[0191] Furthermore, a minimum distance L2 between a side edge of the second connecting section 23 away from the main section 22 along its extension direction and the first welding portion 13 satisfies the relationship: L2 ≥ 0.1 mm, so as to further reduce the risk of a coverage blind spot.

[0192] As an example, the minimum distance L2 may be, but is not limited to, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, etc.

[0193] Fig.10 A schematic cross-sectional structure diagram of another battery cell provided in some embodiments of the present application is shown in FIG. Fig.11 for Fig.10 Schematic diagram of the local enlarged structure at D.

[0194] Continue to refer Figure 10 to Figure 11 In some embodiments, a coating 14 is disposed on the housing 10 , the coating 14 surrounds the first welding portion 13 , and the first protective layer 20 is connected to the coating 14 .

[0195] Exemplarily, the first protective layer 20 is connected to the plating layer 14, and the outer edge of the first protective layer 20 may be connected to the edge of the plating layer 14, in other words, the first protective layer 20 is spliced ​​with the plating layer 14; or the first protective layer 20 and the plating layer 14 may be stacked, and the first protective layer 20 is connected to the outer surface of the plating layer 14, in other words, the first protective layer 20 is connected to the side surface of the plating layer 14 facing away from the electrode assembly 30.

[0196] Optionally, the end cover 12 may be provided with a coating 14, and the coating 14 covers the surface of the end cover 12; the shell 11 may be provided with a coating 14, and the coating 14 covers the surface of the shell 11; or both the end cover 12 and the shell 11 may be provided with a coating 14, and the coating 14 covers the entire surface of the shell 10.

[0197] Optionally, the coating 14 may be directly connected to the housing 10, or may be restricted to the housing 10 through other components. As an example, the coating 14 and the housing 10 may be connected by, but not limited to, bonding, riveting, or bolting.

[0198] Optionally, the coating 14 may be but is not limited to being made of metal or non-metal materials. For example, the metal material may be nickel, copper, aluminum or stainless steel, etc.; the non-metal material may be acrylate, polyurethane, epoxy resin, polyethylene, polypropylene or polyvinyl chloride, etc.

[0199] In the above technical solution, by providing a coating 14 on the housing 10 , the coating 14 can protect the surface of the housing 10 , thereby further improving the overall reliability of the housing 10 .

[0200] In some embodiments, the thickness d1 of the plating layer 14 satisfies the relationship: 0.1 μm≤d1≤10 μm.

[0201] Exemplarily, the thickness d1 of the coating 14 can be but is not limited to 0.1μm, 0.2μm, 0.3μm, 0.4μm, 0.5μm, 0.8μm, 1μm, 1.2μm, 1.5μm, 1.8μm, 2μm, 2.2μm, 2.5μm, 2.8μm, 3μm, 3.2μm, 3.5μm, 3.8μm, 4μm, 4.2μm, 4.5μm, 4.8μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, etc.

[0202] By setting the thickness d1 of the plating layer 14 within the above range, the reliability of the outer casing 10 as a whole can be improved while reducing the influence of the plating layer 14 on the overall size of the battery cell 7 .

[0203] Furthermore, the thickness d1 of the plating layer 14 satisfies the relationship: 0.5 μm≤d1≤5 μm, so as to further take into account the overall reliability of the housing 10 and the overall size of the battery cell 7 .

[0204] Exemplarily, the thickness d1 of the coating 14 may be, but is not limited to, 0.5 μm, 0.8 μm, 1 μm, 1.2 μm, 1.5 μm, 1.8 μm, 2 μm, 2.2 μm, 2.5 μm, 2.8 μm, 3 μm, 3.2 μm, 3.5 μm, 3.8 μm, 4 μm, 4.2 μm, 4.5 μm, 4.8 μm, 5 μm, etc.

[0205] In some embodiments, the first welding portion 13 includes a transition surface 131 , and the transition surface 131 is connected to the outer surface of the shell 11 and the outer surface of the end cover 12 .

[0206] The transition surface 131 refers to at least a portion of the surface of the first welding portion 13 connected to the outer surface of the housing 11 and the outer surface of the end cover 12. By providing the transition surface 131, a smooth transition can be made between the surface of the first welding portion 13 and the outer surface of the housing 11, and between the surface of the first welding portion 13 and the outer surface of the end cover 12. On the one hand, the difficulty of providing the first protective layer 20 can be reduced; on the other hand, the overall surface smoothness of the battery cell 7 can be improved, which is conducive to improving the quality of the battery cell 7.

[0207] In some embodiments, the transition surface 131 is an arc surface.

[0208] It is understandable that, in the process of welding the end cover 12 and the shell 11, the welding difficulty is lower when the surface of the first welding portion 13 is a circular arc surface, compared with the surface of the first welding portion 13 being a flat surface. However, the tension of the circular arc surface is greater than that of the flat surface, making it more difficult to set the first protective layer 20. Thus, by increasing the curvature of the circular arc surface, the surface tension of the circular arc surface can be reduced accordingly, thereby further reducing the difficulty of setting the first protective layer 20.

[0209] In some embodiments, the curvature R of the arc surface satisfies the relationship: R ≥ 100 μm.

[0210] As an example, the curvature R of the arc surface can be but is not limited to 100μm, 150μm, 200μm, 250μm, 300μm, 350μm, 400μm, 450μm, 500μm, 550μm, 600μm, 750μm, 800μm, 850μm, 900μm, 950μm, 1000μm, etc.

[0211] The above technical solution can further reduce the difficulty of preparing the first protective layer 20 and improve the product yield by setting the curvature R of the arc surface to satisfy the above relationship.

[0212] Furthermore, the curvature R of the arc surface satisfies the relationship: R≥200 μm.

[0213] As an example, the curvature R of the arc surface can be but is not limited to 200μm, 250μm, 300μm, 350μm, 400μm, 450μm, 500μm, 550μm, 600μm, 750μm, 800μm, 850μm, 900μm, 950μm, 1000μm, etc.

[0214] In some embodiments, the thickness d2 of the first protective layer 20 satisfies the relationship: d2 ≥ 5 μm.

[0215] Exemplarily, the thickness d2 of the first protective layer 20 can be but is not limited to 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, etc.

[0216] The above technical solution can further improve the protective effect of the first protective layer 20 on the first welding portion 13 by setting the thickness d2 of the first protective layer 20 to satisfy the above relationship.

[0217] Further, the thickness d2 of the first protective layer 20 satisfies the relationship: d2 ≥ 10 μm.

[0218] Exemplarily, the thickness d2 of the first protective layer 20 may be, but is not limited to, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, etc.

[0219] For example, the thickness of the first protective layer 20 can be detected by comparing the grayscale value. The grayscale value of the lower limit of the thickness of the first protective layer 20 can be set as a threshold. If it is higher than the threshold, it can be determined that the thickness of the first protective layer 20 is insufficient; if it is lower than the threshold, it can be determined that the thickness of the first protective layer 20 meets the standard.

[0220] In some embodiments, the first protection layer 20 is a transparent structure.

[0221] Exemplarily, the first protective layer 20 may be made of a transparent material, which can further optimize the appearance of the product.

[0222] In some embodiments, the first protective layer 20 includes a fluorescent member.

[0223] For example, by setting a fluorescent component, the thickness of the first protective layer 20 can be detected by comparing the fluorescence value. The fluorescence value of the lower limit of the thickness of the first protective layer 20 can be set as a threshold. If it is higher than the threshold, it can be determined that the thickness of the first protective layer 20 is insufficient; if it is lower than the threshold, it can be determined that the thickness of the first protective layer 20 meets the standard, which can further improve the accuracy of the thickness detection of the first protective layer 20.

[0224] In some embodiments, the first protective layer 20 includes a coating material including polyacrylate, polyurethane, or epoxy resin.

[0225] Exemplarily, the coating material is coated on the first welding portion 13 through a coating process to form the first protective layer 20. The process is simple, which is conducive to reducing the difficulty of preparing the first protective layer 20 and reducing the cost. Optionally, the coating process can be but is not limited to spraying, printing or dispensing.

[0226] In some embodiments, the viscosity η of the coating material satisfies the relationship: 1 cps≤η≤2000 cps.

[0227] Illustratively, the viscosity η of the coating material may be, but is not limited to, 1cps, 50cps, 100cps, 150cps, 200cps, 250cps, 300cps, 350cps, 400cps, 450cps, 500cps, 550cps, 600cps, 650cps, 700cps, 750cps, 800cps, 850cps, 900cps, 950cps, 1000cps, 1200cps, 1400cps, 1600cps, 1800cps, 2000cps, and the like.

[0228] The viscosity of the coating material can be measured by using a rotational viscometer according to the national standard GB / T 24148.4-2009. The specific measurement method can be referred to the national standard GB / T 24148.4-2009 and will not be described in detail here.

[0229] The above technical solution can effectively improve the coating quality and increase the product yield by setting the viscosity η of the coating material within the above range.

[0230] Furthermore, the viscosity η of the coating material satisfies the relationship: 1cps≤η≤1000cps, so as to further improve the coating quality and product yield.

[0231] Illustratively, the viscosity η of the coating material may be, but is not limited to, 1cps, 50cps, 100cps, 150cps, 200cps, 250cps, 300cps, 350cps, 400cps, 450cps, 500cps, 550cps, 600cps, 650cps, 700cps, 750cps, 800cps, 850cps, 900cps, 950cps, 1000cps, etc.

[0232] In some embodiments, the adhesion between the first protection layer 20 and the first welding portion 13 ranges from level 0 to level 1.

[0233] For example, adhesion refers to the degree of firmness with which a coating is bonded to the surface of an object through the action of physical and chemical forces. The above-mentioned adhesion grade is tested using the cross-cut method of the national standard ISO2409.

[0234] By setting the adhesion between the first protective layer 20 and the first welding portion 13 to satisfy the above relationship, the reliability of the connection between the first protective layer 20 and the first welding portion 13 can be further improved, and the risk of the first protective layer 20 falling off can be reduced.

[0235] Fig.12 A schematic cross-sectional structure diagram of another battery cell provided in some embodiments of the present application is shown. Fig.13 for Fig.12 Schematic diagram of the local enlarged structure at E.

[0236] Continue to refer Figure 12 to Figure 13 In some embodiments, the end cap 12 is further provided with a second welding portion 121 , which is electrically connected to the electrode assembly 30 of the battery cell 7 . The battery cell 7 further includes a second protective layer 50 , which covers the surface of the second welding portion 121 .

[0237] Exemplarily, the electrode assembly 30 includes a main body and a tab, and the electrode assembly 30 is connected to an external electrical device through an electrical connection between the tab and the end cap 12. The end cap 12 and the electrode assembly 30 may be electrically connected by welding, so that the end cap 12 and the electrode assembly 30 are welded to form a second welding portion 121 on the end cap 12.

[0238] As described above, the second protective layer 50 covers the surface of the second welding portion 121. In other words, the second protective layer 50 covers the second welding portion 121 from the outside of the end cover 12 to isolate the second welding portion 121 from the external environment, thereby isolating water vapor and reducing the risk of rusting the second welding portion 121. In addition, the second protective layer 50 itself has a certain hardness, thereby reducing the risk of scratches or bruises on the second welding portion 121, thereby further improving the reliability of the battery cell 7.

[0239] In some embodiments, the first protective layer 20 and the second protective layer 50 are integrally formed. On the one hand, there is no need to connect the first protective layer 20 and the second protective layer 50 through an additional connection process, which simplifies the manufacturing process. At the same time, compared with connecting the first protective layer 20 and the second protective layer 50 through an additional connection process, the first protective layer 20 and the second protective layer 50 in an integral structure have a higher connection firmness.

[0240] In some embodiments, the battery cell 7 further includes a current collector 60 , which is connected between the end cover 12 and the electrode assembly 30 , and the current collector 60 is welded to the second welding portion 121 .

[0241] Exemplarily, the current collector 60 is arranged between the electrode assembly 30 and the end cover 12. The end cover 12, the current collector 60 and the electrode assembly 30 are connected by welding to form a second welding portion 121 to achieve electrical connection among the end cover 12, the current collector 60 and the electrode assembly 30. The current collector 60 can improve the stability of the electrical connection between the electrode assembly 30 and the end cover 12.

[0242] According to some embodiments of the present application, the present application also provides a battery, comprising a battery cell 7 of any of the above schemes.

[0243] According to some embodiments of the present application, the present application further provides an electrical device, comprising a battery cell 7 according to any of the above schemes, and the battery cell 7 is used to provide electrical energy.

[0244] In order to better understand the battery cell 7 provided in the embodiment of the present application, based on the same inventive concept, an embodiment of the above-mentioned battery cell 7 in actual application is provided here for illustration.

[0245] The embodiment of the present application provides a battery cell 7, which includes a shell 10, an electrode assembly 30, a first protective layer 20 and an insulating member 40, and the electrode assembly 30 is accommodated in the shell 10. The shell 10 includes a shell 11 and an end cover 12, the shell 11 has an opening 111, the shell 11 includes a side wall 112 surrounding the electrode assembly 30, the side wall 112 is provided with a recess 1121, the recess 1121 is recessed relative to the outer surface of the side wall 112, the end cover 12 covers the opening 111, and the end cover 12 is welded to the bottom wall of the recess 1121 to form a first welding portion 13. The first protective layer 20 includes a first connecting section 21, a main section 22 and a second connecting section 23 connected to each other, and the main section 22 is located between the first connecting section 21 and the second connecting section 23. The first connecting section 21 is connected to the side of the side wall 112 facing away from the electrode assembly 30, the second connecting section 23 is connected to the side of the end cover 12 facing away from the electrode assembly 30, and the main section 22 covers the surface of the first welding portion 13. The insulating member 40 is connected to a side of the side wall 112 facing away from the electrode assembly 30 .

[0246] The first connecting section 21 is spaced apart from the insulating member 40, or the first connecting section 21 is connected to the insulating member 40 along a side edge away from the main section 22 along its own extension direction, or the first connecting section 21 and the insulating member 40 are at least partially stacked along the thickness direction of the side wall 112, or the first protective layer 20 and the insulating member 40 are an integrally formed structure.

[0247] The above technical solution provides the first protective layer 20 , and the first protective layer 20 covers the surface of the first welding portion 13 , thereby reducing the risk of rust or damage to the first welding portion 13 , thereby effectively improving the reliability of the battery cell 7 .

[0248] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0249] 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: The housing comprises a shell and an end cover, wherein the shell has an opening, the end cover covers the opening, and the end cover is welded to the shell to form a first welding portion; The first protective layer covers the surface of the first welding portion.

2. The battery cell according to claim 1, characterized in that: The first protective layer comprises a first connecting segment, a main segment and a second connecting segment connected to each other, wherein the main segment is located between the first connecting segment and the second connecting segment; The first connecting section is connected to the shell, the second connecting section is connected to the end cover, and the main body section covers the surface of the first welding portion.

3. The battery cell according to claim 2, characterized in that: The battery cell further includes an electrode assembly, and the electrode assembly is accommodated in the housing; The shell includes a side wall surrounding the electrode assembly, the first connecting section is connected to a side of the side wall facing away from the electrode assembly, and the second connecting section is connected to a side of the end cover facing away from the electrode assembly.

4. The battery cell according to claim 3, characterized in that: The battery cell further includes an insulating member connected to a side of the side wall facing away from the electrode assembly.

5. The battery cell according to claim 4, characterized in that: The first connecting section is spaced apart from the insulating member.

6. The battery cell according to claim 4, characterized in that: The first connecting section is connected to the insulating member along a side edge portion of the first connecting section away from the main body section along its own extending direction.

7. The battery cell according to claim 6, characterized in that: Along the thickness direction of the side wall, a surface of the first connecting section facing away from the side wall is flush with a surface of the insulating member facing away from the side wall.

8. The battery cell according to claim 4, characterized in that: Along the thickness direction of the side wall, the first connecting section and the insulating member are at least partially overlapped.

9. The battery cell according to claim 4, characterized in that: The first protective layer and the insulating member are integrally formed.

10. The battery cell according to claim 3, characterized in that: The side wall is provided with a recessed portion, the recessed portion being recessed relative to the outer surface of the side wall; The bottom wall of the recess is welded to the end cover to form the first welding portion, and at least a portion of the first connecting section is accommodated in the recess.

11. The battery cell according to claim 10, characterized in that: Along the thickness direction of the side wall, a surface of a side of the first connecting section facing away from the electrode assembly is flush with a surface of a side of the side wall facing away from the electrode assembly.

12. The battery cell according to claim 11, characterized in that: Along the thickness direction of the end cover, a surface of the second connecting section facing away from the electrode assembly is flush with a surface of the end cover facing away from the electrode assembly.

13. The battery cell according to claim 2, characterized in that: The minimum distance L1 between the first welding portion and a side edge of the first connecting section away from the main section along its extension direction satisfies the relationship: L1 ≥ 0.05 mm; A minimum distance L2 between a side edge of the second connecting section away from the main section along its extension direction and the first welding portion satisfies the relationship: L2≥0.05 mm.

14. The battery cell according to claim 13, characterized in that: The minimum distance L1 satisfies the relationship: L1 ≥ 0.1 mm, and the minimum distance L2 satisfies the relationship: L2 ≥ 0.1 mm.

15. The battery cell according to claim 1, characterized in that: A plating layer is disposed on the shell, the plating layer surrounds the first welding portion, and the first protective layer is connected to the plating layer.

16. The battery cell according to claim 15, characterized in that: The thickness d1 of the coating satisfies the relationship: 0.1 μm≤d1≤10 μm.

17. The battery cell according to claim 16, characterized in that: The thickness d1 of the coating satisfies the relationship: 0.5 μm≤d1≤5 μm.

18. The battery cell according to claim 1, characterized in that: The first welding portion includes a transition surface, and the transition surface is connected to the outer surface of the shell and the outer surface of the end cover.

19. The battery cell according to claim 18, characterized in that: The transition surface is an arc surface.

20. The battery cell according to claim 19, characterized in that: The curvature R of the arc surface satisfies the relationship: R≥100 μm.

21. The battery cell according to claim 20, characterized in that: The arc R satisfies the relationship: R≥200 μm.

22. The battery cell according to claim 1, characterized in that: The thickness d2 of the first protective layer satisfies the relationship: d2 ≥ 5 μm.

23. The battery cell according to claim 21, characterized in that: The thickness d2 of the first protective layer satisfies the relationship: d2 ≥ 10 μm.

24. The battery cell according to claim 1, characterized in that The first protective layer is a transparent structure.

25. The battery cell according to claim 24, characterized in that: The first protection layer includes a fluorescent element.

26. The battery cell according to claim 1, characterized in that: The first protective layer is polyacrylate, polyurethane or epoxy resin.

27. The battery cell according to claim 26, characterized in that: The viscosity η of the first protective layer satisfies the relationship: 1cps≤η≤2000cps.

28. The battery cell according to claim 27, characterized in that: The viscosity η of the first protective layer satisfies the relationship: 1cps≤η≤1000cps.

29. The battery cell according to claim 1, characterized in that: The adhesion between the first protective layer and the first welding portion ranges from level 0 to level 1.

30. The battery cell according to claim 1, characterized in that The end cover is also provided with a second welding portion, and the second welding portion is electrically connected to the electrode assembly of the battery cell; The battery cell further includes a second protective layer, and the second protective layer covers a surface of the second welding portion.

31. The battery cell according to claim 30, characterized in that: The first protective layer and the second protective layer are an integrally formed structure.

32. The battery cell according to any one of claims 1 to 31, characterized in that: The battery cell is a cylindrical battery cell.

33. A battery, characterized in that: Comprising a battery cell as described in any one of claims 1-32.

34. An electrical device, characterized in that: The invention comprises a battery cell as described in any one of claims 1 to 32, wherein the battery cell is used to provide electrical energy.

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