Battery monomer, battery and electric device

Abstract

The invention 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.

Description

Battery cells, batteries and electrical devices

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202323249549.8, entitled “Battery Cell, Battery and Electrical Device,” filed on November 29, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] 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

[0004] With the development of new energy technology, batteries are used more and more widely, for example, in mobile phones, laptops, electric vehicles, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes and power tools.

[0005] In a battery cell, the housing is a key component and is crucial to its stable and reliable operation. The reliability of the housing directly affects the quality of the battery cell. Therefore, the reliability of the housing is a key research topic in battery technology.

[0006] Summary of the Invention

[0007] 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.

[0008] In a first aspect, embodiments of the present application provide a battery cell, comprising an outer shell and a first protective layer. The outer shell comprises a housing and an end cap. The housing has an opening, the end cap covers the opening, and the end cap is welded to the housing to form a first weld. The first protective layer covers a surface of the first weld.

[0009] 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.

[0010] In some embodiments of the first aspect, the first protective layer includes a first connecting segment, a main segment, and a second connecting segment, wherein the main segment is located between the first connecting segment and the second connecting segment. The first connecting segment is connected to the housing, the second connecting segment is connected to the end cap, and the main segment covers the surface of the first weld portion.

[0011] 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.

[0012] In some embodiments of the first aspect, the battery cell further comprises an electrode assembly, the electrode assembly being housed in a housing. The housing includes a sidewall surrounding the electrode assembly, the first connecting segment being connected to a side of the sidewall facing away from the electrode assembly, and the second connecting segment being connected to a side of the end cap facing away from the electrode assembly.

[0013] The above technical solution is convenient to operate, has low difficulty and is conducive to reducing costs by welding the end cover and the shell body outside the shell and providing a first protective layer.

[0014] 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.

[0015] 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.

[0016] 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 manufacturing difficulty is relatively low, which is conducive to reducing costs and improving product yield.

[0017] In some embodiments of the first aspect, the first connecting section is connected to the insulating member along a side edge of the first connecting section that is away from the main body section along its own extending direction.

[0018] 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, they can effectively improve the consistency of the outer surface of the shell, which is beneficial to improving the appearance of the battery cell.

[0019] 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 side wall is flush with a surface of the insulating member facing away from the side wall. This can effectively improve the flatness of the outer surface of the housing, thereby further enhancing the aesthetic appearance of the battery cell.

[0020] In some embodiments of the first aspect, along a thickness direction of the sidewall, the first connecting segment and the insulating member are at least partially overlapped.

[0021] 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 coverage dead angles, thereby further improving the protection effect of the first connecting section and the insulating member on the shell, which is conducive to improving the reliability of the shell.

[0022] In some embodiments of the first aspect, the first protective layer and the insulating member are an integrally formed structure.

[0023] On the one hand, there is no need to connect the first protective layer to the insulating member through an additional connection process, which simplifies the manufacturing process. At the same time, compared with connecting the first protective layer to the insulating member through an additional connection process, the integrated structure of the first protective layer and the insulating member has a higher connection strength.

[0024] 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.

[0025] 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.

[0026] In some embodiments of the first aspect, along the thickness direction of the sidewall, a surface of the first connecting segment facing away from the electrode assembly is flush with a surface of the sidewall facing away from the electrode assembly, thereby improving the flatness of the outer surface of the sidewall and optimizing the appearance of the product.

[0027] In some embodiments of the first aspect, along the thickness direction of the end cap, a surface of the second connecting segment facing away from the electrode assembly is flush with a surface of the end cap facing away from the electrode assembly. This can improve the flatness of the outer surface of the end cap, thereby further optimizing the appearance of the product.

[0028] In some embodiments of the first aspect, a minimum distance L1 between a side edge of the first connecting section, which is distal to the main body section, and the first welding portion along its extension direction satisfies the relationship: L1 ≥ 0.05 mm. A minimum distance L2 between a side edge of the second connecting section, which is distal to the main body section, and the first welding portion along its extension direction satisfies the relationship: L2 ≥ 0.05 mm.

[0029] 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 side edge of the first connecting section away from the main section along its own extension direction and the first welding part and the minimum distance L2 between the side edge of the second connecting section away from the main section along its own extension direction and the first welding part within the above range, thereby further improving the reliability of the battery cell.

[0030] 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 coverage blind spots.

[0031] In some embodiments of the first aspect, a plating layer is provided on the housing, the plating layer surrounds the first welding portion, and the first protective layer is connected to the plating layer.

[0032] The above technical solution provides a coating on the housing, and the coating can protect the surface of the housing, thereby further improving the reliability of the housing as a whole.

[0033] 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 impact of the coating on the overall size of the battery cell.

[0034] 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.

[0035] 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.

[0036] 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 conducive to improving the quality of the battery cell.

[0037] In some embodiments of the first aspect, the transition surface is an arc surface.

[0038] The above technical solution can reduce the difficulty of welding the end cover and the shell by setting the surface of the first welding part to a circular arc surface, while reducing the difficulty of preparing the first protective layer, and can effectively improve the product yield.

[0039] In some embodiments of the first aspect, the curvature R of the arc surface satisfies the relationship: R ≥ 100 μm.

[0040] 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.

[0041] In some embodiments of the first aspect, the radian R satisfies the relationship: R ≥ 200 μm.

[0042] 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.

[0043] In some embodiments of the first aspect, a thickness d2 of the first protective layer satisfies the relationship: d2 ≥ 10 μm.

[0044] In some embodiments of the first aspect, the first protective layer is a transparent structure, which can further optimize the appearance of the product.

[0045] 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.

[0046] In some embodiments of the first aspect, the first protective layer includes a coating material including polyacrylate, polyurethane, or epoxy resin.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] In some embodiments of the first aspect, the end cap further comprises a second welding portion electrically connected to the electrode assembly of the battery cell. The battery cell further comprises a second protective layer covering a surface of the second welding portion.

[0053] This technical solution isolates the second weld from the external environment, thereby isolating it from moisture and reducing the risk of rust. Furthermore, the second protective layer itself has a certain hardness, which reduces the risk of scratches or impacts on the second weld, further improving the reliability of the battery cell.

[0054] In some embodiments of the first aspect, the first protective layer and the second protective layer are an integrally formed structure.

[0055] On the one hand, there is no need to connect the first and second protective layers through an additional connection process, which simplifies the manufacturing process. At the same time, compared with connecting the first and second protective layers through an additional connection process, the integrated structure of the first and second protective layers has a higher connection strength.

[0056] In some embodiments of the first aspect, the battery cell is a cylindrical battery cell.

[0057] In a second aspect, the present application provides a battery comprising the battery cell provided in any embodiment of the first aspect.

[0058] In a third aspect, the present application provides an electrical device, which includes a battery cell provided by any embodiment of the first aspect, and the battery cell is used to provide electrical energy.

[0059] 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

[0060] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0061] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0062] FIG2 is a schematic diagram of an exploded structure of a battery provided in some embodiments of the present application;

[0063] FIG3 is a schematic cross-sectional view of a battery cell provided in some embodiments of the present application;

[0064] FIG4 is a schematic cross-sectional view of a housing of a battery cell provided in some embodiments of the present application;

[0065] FIG5 is a schematic diagram of a partially enlarged structure of point A in FIG3 ;

[0066] FIG6 is a schematic cross-sectional view of another battery cell provided in some embodiments of the present application;

[0067] FIG7 is a schematic diagram of a partially enlarged structure of point B in FIG6 ;

[0068] FIG8 is a schematic cross-sectional view of another battery cell provided in some embodiments of the present application;

[0069] FIG9 is a schematic diagram of a partially enlarged structure of point C in FIG8 ;

[0070] FIG10 is a schematic cross-sectional view of another battery cell provided in some embodiments of the present application;

[0071] FIG11 is a schematic diagram of a partially enlarged structure of point D in FIG10 ;

[0072] FIG12 is a schematic cross-sectional view of another battery cell provided in some embodiments of the present application;

[0073] FIG13 is a schematic diagram of a partially enlarged structure of point E in FIG12 .

[0074] The accompanying drawings in the specific implementation manner are as follows:

[0075] 1. Vehicle; 2. Battery; 3. Controller; 4. Motor; 5. Box; 7. Battery Cell;

[0076] 10. Outer 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 collecting member. DETAILED DESCRIPTION

[0077] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0078] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are 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" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0079] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0080] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0081] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0082] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0083] The term "plurality" used in this application refers to two or more (including two).

[0084] In this application, the term "parallel" includes not only the absolutely parallel situation, but also the roughly parallel situation conventionally recognized in engineering; at the same time, "vertical" also includes not only the absolutely vertical situation, but also the roughly vertical situation conventionally recognized in engineering.

[0085] In this application, battery cells may include lithium-ion secondary battery cells, lithium-ion primary battery cells, lithium-sulfur battery cells, sodium-lithium-ion battery cells, sodium-ion battery cells, or magnesium-ion battery cells, and the embodiments of this application are not limited thereto. Battery cells may be cylindrical, flat, rectangular, or in other shapes, and the embodiments of this application are not limited thereto.

[0086] 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 hybrid through a busbar.

[0087] 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.

[0088] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are housed in the case.

[0089] 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.

[0090] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0091] A battery cell typically includes an electrode assembly. This assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of a battery cell, active ions (such as lithium ions) are inserted and removed between the positive and negative electrodes. The separator, placed between the positive and negative electrodes, prevents short circuits between the positive and negative electrodes while allowing the active ions to pass through.

[0092] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0093] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0094] 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 may be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0095] 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 modified compounds thereof. However, this application is not limited to these materials; 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 singly or in combination of two or more.

[0096] In some embodiments, the positive electrode may be a carbon foam or a metal foam. The metal foam may be nickel foam, copper foam, aluminum foam, or an alloy foam, among others. When the metal foam is used as the positive electrode, the surface of the metal foam may or may not be provided with a positive electrode active material. For example, a lithium source material, potassium metal, or sodium metal may be filled and / or deposited within the metal foam, where the lithium source material is lithium metal and / or a lithium-rich material.

[0097] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0098] 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 a silver surface treatment may be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (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.).

[0099] 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.

[0100] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is provided on either or both of the two facing surfaces of the negative electrode current collector.

[0101] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate.

[0102] In some embodiments, the negative electrode may be made of 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 negative electrode sheet, the surface of the metal foam may or may not be provided with a negative electrode active material.

[0103] As an example, the negative electrode current collector may be filled with or / and deposited with a lithium source material, potassium metal, or sodium metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0104] 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.

[0105] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0106] In some embodiments, the separator is a separator membrane, which can be any known porous separator membrane with good chemical and mechanical stability.

[0107] 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.

[0108] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transport ions and isolate the positive and negative electrodes.

[0109] In some embodiments, the battery cell further includes an electrolyte, which functions to conduct ions between the positive and negative electrodes. The electrolyte may be in liquid, gel, or solid form.

[0110] 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.

[0111] In some embodiments, the electrode assembly is a laminate structure.

[0112] As an example, multiple positive electrode sheets and multiple negative electrode sheets can be provided respectively, and the multiple positive electrode sheets and the multiple negative electrode sheets can be alternately stacked.

[0113] 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.

[0114] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of stacked folded segments.

[0115] As an example, a plurality of separators may be provided, each of which is disposed between any adjacent positive electrode sheets or negative electrode sheets.

[0116] As an example, the separator may be provided continuously, and may be provided between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0117] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0118] In some embodiments, the electrode assembly is provided with tabs that can conduct current from the electrode assembly. The tabs include a positive tab and a negative tab.

[0119] With the development of new energy technology, batteries are used more and more widely, for example, in mobile phones, laptops, electric vehicles, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes and power tools.

[0120] The outer shell of a battery cell is a crucial component, crucial for its stable and reliable operation. Its reliability directly impacts its quality. Currently, the outer shell is typically formed by welding the shell and end caps. However, the welded area between the shell and end caps is less reliable, and during transportation, storage, and use, the welded area is susceptible to corrosion or damage, impacting the reliability of the battery cell.

[0121] Based on the above considerations, the present application designs a battery cell, which includes an outer shell and a first protective layer. The outer shell includes a shell and an end cap. The shell has an opening, and the end cap covers the opening. The end cap is welded to the shell to form a first welded portion, and the first protective layer covers the surface of the first welded portion. In this way, the first protective layer can protect the first welded portion, reducing the risk of rust or damage to the first welded portion, thereby effectively improving the reliability of the battery cell.

[0122] The technical solutions described in the embodiments of the present application are applicable to batteries and electrical devices using batteries.

[0123] Electrical devices include, but are not limited to, vehicles, mobile phones, portable devices, laptop computers, ships, spacecraft, electric toys, and electric tools. Vehicles include, but are not limited to, gasoline-powered vehicles, gas-powered vehicles, or new energy vehicles; new energy vehicles include, but are not limited to, pure electric vehicles, hybrid vehicles, or extended-range vehicles; spacecraft include, but are not limited to, airplanes, rockets, space shuttles, and spacecraft; 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; and electric tools include, but are not limited to, 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.

[0124] 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 explained using electric vehicles as an example.

[0125] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application.

[0126] 1 , a battery 2 is provided inside the vehicle 1 , and the battery 2 may be provided at the bottom, head, or tail of the vehicle 1 . The battery 2 may be used to power the vehicle 1 , for example, the battery 2 may serve as an operating power source for the vehicle 1 .

[0127] The vehicle 1 may further include a controller 3 and a motor 4 . The controller 3 is used to control the battery 2 to supply power to the motor 4 , for example, to meet the power requirements of the vehicle 1 during startup, navigation, and driving.

[0128] In some embodiments of the present application, the battery 2 can not only serve as the operating power source of the vehicle 1, but also serve as the driving power source of the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0129] FIG2 is a schematic diagram of an explosion of a battery provided in some embodiments of the present application.

[0130] 2 , the battery 2 includes a housing 5 and battery cells 7 , and the battery cells 7 are accommodated in the housing 5 .

[0131] 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.

[0132] In the battery 2, there can be one or more battery cells 7. If there are multiple battery cells 7, the multiple battery cells 7 can be connected in series, in parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections within the multiple battery cells 7. The multiple battery cells 7 can be directly connected in series, in parallel, or in a hybrid connection, and then the entire battery cell 7 can be housed within the housing 5. Alternatively, multiple battery cells 7 can be first connected in series, in parallel, or in a hybrid connection to form a battery module, and then the multiple battery modules can be connected in series, in parallel, or in a hybrid connection to form a single unit and housed within the housing 5.

[0133] Figure 3 is a schematic diagram of the cross-sectional structure of a battery cell provided in some embodiments of the present application, Figure 4 is a schematic diagram of the cross-sectional structure of a shell of a battery cell provided in some embodiments of the present application, and Figure 5 is a schematic diagram of the partial enlarged structure of point A in Figure 3.

[0134] Continuing to refer to Figures 3 to 5, an 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, and 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.

[0135] 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.

[0136] Optionally, the shell 11 may be in various shapes and sizes, including 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 .

[0137] Optionally, the material of the housing 11 may be, but is not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0138] The end cap 12 is 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 cap 12 can be adapted to the shape of the housing 11 to match the housing 11 .

[0139] Optionally, the end cap 12 can be made of a material with a certain degree of hardness and strength, including but not limited to copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. This makes the end cap 12 less susceptible to deformation during compression and collision, thereby enhancing the structural strength of the battery cell 7 and improving reliability. For example, the end cap 12 and the housing 11 can be made of the same material to simplify the manufacturing process and reduce costs.

[0140] As an example, functional components such as electrode terminals may be provided on the end cap 12 , and the electrode terminals may be used to electrically connect to the electrode assembly 30 for outputting or inputting electrical energy of the battery cell 7 .

[0141] 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.

[0142] As an example, an insulating member may be provided inside the end cap 12 to isolate the electrical connection components in the housing 11 from the end cap 12 to reduce the risk of short circuit.

[0143] Exemplarily, the end cap 12 and the housing 11 are connected by welding, forming a first connection portion at the junction of the end cap 12 and the housing 11. The first protective layer 20 covers the surface of the first weld portion 13, isolating the first weld portion 13 from the external environment, thereby isolating the first weld portion 13 from moisture and reducing the risk of rust on the first weld portion 13. Furthermore, the first protective layer 20 itself has a certain hardness, thereby reducing the risk of scratches or impacts on the first weld portion 13.

[0144] Optionally, the first welding portion 13 may be located inside the outer shell 10, thereby improving the aesthetic appearance of the battery cell 7. Alternatively, the first welding portion 13 may be located outside the outer shell 10, thereby facilitating welding operations and reducing welding difficulty. For example, when the first welding portion 13 is located inside the outer shell 10, a welding hole may be provided on the end cap 12, which penetrates the end cap 12 along its thickness. After the end cap 12 is fitted over the opening 111 of the shell 11, a welding gun may weld the end cap 12 and the shell 11 from inside the outer shell 10 through the welding hole. When the first welding portion 13 is located outside the outer shell 10, the welding gun may weld the end cap 12 and the shell 11 directly from outside the outer shell 10.

[0145] Optionally, the first welding portion 13 may be located inside the outer shell 10, thereby improving the aesthetic appearance of the battery cell 7. Alternatively, the first welding portion 13 may be located outside the outer shell 10, thereby facilitating welding operations and reducing welding difficulty. For example, when the first welding portion 13 is located inside the outer shell 10, a welding hole may be provided on the end cap 12, which penetrates the end cap 12 along its thickness. After the end cap 12 is fitted over the opening 111 of the shell 11, a welding gun may weld the end cap 12 and the shell 11 from inside the outer shell 10 through the welding hole. When the first welding portion 13 is located outside the outer shell 10, the welding gun may weld the end cap 12 and the shell 11 directly from outside the outer shell 10.

[0146] 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.

[0147] Optionally, the first protective layer 20 can be but is not limited to being made of metal or non-metal materials. For example, the metal material can be copper, aluminum or stainless steel, etc.; the non-metal material can be acrylate, polyurethane, epoxy resin, polyethylene, polypropylene or polyvinyl chloride, etc.

[0148] The above technical solution provides the first protective layer 20 , which 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 .

[0149] 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 .

[0150] 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 cap 12, and the main segment 22 covers the surface of the first welding portion 13.

[0151] For example, the first connecting section 21 extends from the main section 22 in a direction close to the housing 11 and is connected to the housing 11, 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 end cap 12. On the one hand, this can further improve the coverage of the first welding portion 13 by the first protective layer 20, reducing the risk of blind spots in coverage; on the other hand, the first and second connecting portions can also improve the connection strength of the first protective layer 20, reducing the risk of the first protective layer 20 falling off.

[0152] Optionally, the first connecting section 21 may be directly connected to the housing 11 or may be secured to the housing 11 via other components. For example, the connection between the first connecting section 21 and the housing 11 may be, but is not limited to, bonding, riveting, or bolting.

[0153] Optionally, the second connecting 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 connecting section 23 and the end cover 12 may be, but is not limited to, bonding, riveting, or bolting.

[0154] In some embodiments, the battery cell 7 further includes an electrode assembly 30, which is housed in the housing 10. The housing 11 includes a sidewall 112 surrounding the electrode assembly 30, the first connecting segment 21 is connected to a side of the sidewall 112 facing away from the electrode assembly 30, and the second connecting segment 23 is connected to a side of the end cap 12 facing away from the electrode assembly 30.

[0155] The electrode assembly 30 is a component in the battery cell 7 where electrochemical reactions occur. One or more electrode assemblies 30 may be contained 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 and negative electrode tabs 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 electrode active material and the negative electrode active material react with the electrolyte, and the tabs connect the electrode terminals to form a current loop.

[0156] Illustratively, the first welding portion 13 is located outside the housing 10, the first connecting segment 21 extends from the main segment 22 in a direction close to the housing 11 and is connected to the side of the sidewall 112 facing away from the electrode assembly 30, and the second connecting segment 23 extends from the main segment 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 providing the first protective layer 20 from the outside of the housing 10 is easy and less difficult, which helps reduce costs.

[0157] 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 .

[0158] For example, 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 .

[0159] Optionally, the insulating member 40 may be directly connected to the side wall 112, or may be secured to the side wall 112 by other components. As an example, the insulating member 40 and the side wall 112 may be connected by, but not limited to, bonding, riveting, or bolting.

[0160] Optionally, the insulating member 40 may be, but is not limited to, a film structure, a sheet structure, or a block structure.

[0161] Optionally, the insulating member 40 may be made of, but not limited to, polypropylene, polyethylene, or polybutylene, etc. The insulating member 40 may further include a flame retardant, an antioxidant, etc., to improve the performance of the insulating member 40 .

[0162] In some embodiments, the first connecting section 21 is spaced apart from the insulating member 40 .

[0163] For example, along the plane of the sidewall 112, a certain distance exists between the first connecting 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. This configuration simplifies the structural design and reduces the manufacturing difficulty, which helps reduce costs and improve product yield.

[0164] In some embodiments, the first connecting section 21 is connected to the insulating member 40 along a side edge thereof that is away from the main section 22 along its own extending direction.

[0165] For example, the first connecting section 21 is joined to the insulating member 40. In other words, the first connecting 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 connecting section 21 and the insulating member 40 both protect the housing 11, thereby improving the reliability of the housing 11. On the other hand, they effectively improve the consistency of the outer surface of the outer shell 10, thereby enhancing the aesthetic appearance of the battery cell 7.

[0166] 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 .

[0167] Illustratively, the surface of the first connecting section 21 facing away from the side wall 112 and the 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, thereby further improving the appearance of the battery cell 7.

[0168] Figure 6 is a schematic cross-sectional view of another battery cell 7 provided in some embodiments of the present application, Figure 7 is a partially enlarged schematic view of the structure at B in Figure 6 , and Figure 8 is a partially enlarged schematic view of the structure at B in Figure 6 before the end cover 12 and the shell 11 are welded.

[0169] Continuing to refer to FIG. 6 to FIG. 8 , in some embodiments, along the thickness direction of the sidewall 112 , the first connecting segment 21 and the insulating member 40 are at least partially overlapped.

[0170] 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, reduce the risk of coverage dead angles, and thus further improve 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.

[0171] FIG8 is a schematic cross-sectional structural diagram of another battery cell provided in some embodiments of the present application, and FIG9 is a schematic partial enlarged structural diagram of point C in FIG8 .

[0172] 8 and 9 , in some embodiments, the first protective layer 20 and the insulating member 40 are integrally formed.

[0173] For example, a structure with 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 for the first welding portion 13 and the other layer is an insulating layer.

[0174] This simplifies the manufacturing process by eliminating the need for an additional connection process to connect the first protective layer 20 to the insulating member 40. Furthermore, the integrated structure provides a stronger connection between the first protective layer 20 and the insulating member 40 than would be achieved by connecting the first protective layer 20 to the insulating member 40 through an additional connection process.

[0175] 6 and 7 , in some embodiments, the sidewall 112 is provided with a recessed portion 1121 that is recessed relative to the outer surface of the sidewall 112. The bottom wall of the recessed portion 1121 is welded to the end cap 12 to form a first welded portion 13, and at least a portion of the first connecting section 21 is accommodated in the recessed portion 1121.

[0176] 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 accommodating 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.

[0177] 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 .

[0178] 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.

[0179] 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.

[0180] 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 .

[0181] For example, 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.

[0182] 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.

[0183] 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 own extension direction and the first welding portion 13 satisfies the relationship: L1 ≥ 0.05 mm.

[0184] For example, the minimum distance between the first welding portion 13 and a side edge of the first connecting segment 21 away from the main segment 22 along its own extension direction can be understood as the size of the outer edge of the first connecting segment 21 exceeding the edge of the first welding portion 13.

[0185] 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.

[0186] 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.

[0187] Furthermore, the minimum distance L1 between the first welding portion 13 and one side edge of the first connecting section 21 away from the main section 22 along its own extension direction satisfies the relationship: L1 ≥ 0.1 mm, so as to further reduce the risk of coverage blind spots.

[0188] 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.

[0189] 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.

[0190] For example, the minimum distance between the first welding portion 13 and a side edge of the second connecting segment 23 away from the main segment 22 along its own extension direction can be understood as the size of the outer edge of the second connecting segment 23 exceeding the edge of the first welding portion 13.

[0191] 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.

[0192] 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.

[0193] Furthermore, 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 and the first welding portion 13 satisfies the relationship: L2 ≥ 0.1 mm, so as to further reduce the risk of coverage blind spots.

[0194] 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.

[0195] FIG10 is a schematic cross-sectional structural diagram of another battery cell provided in some embodiments of the present application, and FIG11 is a schematic partial enlarged structural diagram of point D in FIG10 .

[0196] Continuing to refer to FIG. 10 and FIG. 11 , in some embodiments, a plating layer 14 is provided on the housing 10 , the plating layer 14 surrounds the first welding portion 13 , and the first protective layer 20 is connected to the plating layer 14 .

[0197] For example, the first protective layer 20 is connected to the plating layer 14, and the outer edge of the first protective layer 20 can 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 can 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.

[0198] 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.

[0199] Optionally, the coating 14 may be directly connected to the housing 10 or may be secured to the housing 10 via other components. For example, the coating 14 and the housing 10 may be connected by, but not limited to, bonding, riveting, or bolting.

[0200] 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; the non-metal material may be acrylate, polyurethane, epoxy resin, polyethylene, polypropylene or polyvinyl chloride.

[0201] The above technical solution provides 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 .

[0202] In some embodiments, the thickness d1 of the plating layer 14 satisfies the relationship: 0.1 μm≤d1≤10 μm.

[0203] Exemplarily, the thickness d1 of the coating 14 may be, but is not limited to, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 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, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, etc.

[0204] By setting the thickness d1 of the plating layer 14 within the above range, the reliability of the entire housing 10 can be improved while reducing the influence of the plating layer 14 on the overall size of the battery cell 7 .

[0205] 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 reliability of the entire housing 10 and the overall size of the battery cell 7.

[0206] Illustratively, 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.

[0207] 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 .

[0208] The transition surface 131 refers to at least a portion of the surface of the first weld portion 13 that connects to the outer surface of the housing 11 and the outer surface of the end cap 12. The provision of the transition surface 131 allows for a smooth transition between the surface of the first weld portion 13 and the outer surface of the housing 11, and also between the surface of the first weld portion 13 and the outer surface of the end cap 12. This, on the one hand, simplifies the installation of the first protective layer 20; on the other hand, it improves the overall surface smoothness of the battery cell 7, thereby enhancing the quality of the battery cell 7.

[0209] In some embodiments, the transition surface 131 is an arc surface.

[0210] It is understood that during welding of the end cap 12 to the housing 11, the welding difficulty is lower when the surface of the first welding portion 13 is a curved surface, compared to a flat surface. However, the tension of a curved surface is greater than that of a flat surface, making it more difficult to install the first protective layer 20. Therefore, by increasing the curvature of the curved surface, the surface tension of the curved surface can be reduced, thereby further reducing the difficulty of installing the first protective layer 20.

[0211] In some embodiments, the arc angle R of the arc surface satisfies the relationship: R≥100 μm.

[0212] As an example, the radian 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.

[0213] 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.

[0214] Furthermore, the arc angle R of the arc surface satisfies the relationship: R≥200 μm.

[0215] As an example, the radian 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.

[0216] In some embodiments, the thickness d2 of the first protective layer 20 satisfies the relationship: d2 ≥ 5 μm.

[0217] 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.

[0218] The above technical solution can further improve the protection 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.

[0219] Furthermore, the thickness d2 of the first protective layer 20 satisfies the relationship: d2 ≥ 10 μm.

[0220] For example, 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.

[0221] For example, the thickness of the first protective layer 20 can be detected by comparing grayscale values. A grayscale value of the lower limit of the thickness of the first protective layer 20 can be set as a threshold. If the grayscale value is above the threshold, it can be determined that the thickness of the first protective layer 20 is insufficient; if the grayscale value is below the threshold, it can be determined that the thickness of the first protective layer 20 meets the standard.

[0222] In some embodiments, the first protection layer 20 is a transparent structure.

[0223] For example, the first protective layer 20 may be made of a transparent material, which can further optimize the appearance of the product.

[0224] In some embodiments, the first protective layer 20 includes a fluorescent element.

[0225] For example, by providing a fluorescent element, the thickness of the first protective layer 20 can be detected by comparing the fluorescence value. A fluorescence value threshold value, which is the lower limit of the thickness of the first protective layer 20, can be set. If the fluorescence value is above the threshold value, it can be determined that the thickness of the first protective layer 20 is insufficient; if the fluorescence value is below the threshold value, it can be determined that the thickness of the first protective layer 20 meets the standard, thereby further improving the accuracy of the thickness detection of the first protective layer 20.

[0226] In some embodiments, the first protective layer 20 includes a coating material including polyacrylate, polyurethane, or epoxy resin.

[0227] For example, a coating material is applied to the first welding portion 13 through a coating process to form the first protective layer 20. This process is simple, which helps to reduce the difficulty and cost of preparing the first protective layer 20. Optionally, the coating process can be, but is not limited to, spraying, printing, or dispensing.

[0228] In some embodiments, the viscosity η of the coating material satisfies the relationship: 1 cps≤η≤2000 cps.

[0229] For example, the viscosity η of the coating material may be, but is not limited to, 1 cps, 50 cps, 100 cps, 150 cps, 200 cps, 250 cps, 300 cps, 350 cps, 400 cps, 450 cps, 500 cps, 550 cps, 600 cps, 650 cps, 700 cps, 750 cps, 800 cps, 850 cps, 900 cps, 950 cps, 1000 cps, 1200 cps, 1400 cps, 1600 cps, 1800 cps, 2000 cps, etc.

[0230] The viscosity of the coating material can be measured using a rotational viscometer in accordance with 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.

[0231] 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.

[0232] Furthermore, 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.

[0233] For example, the viscosity η of the coating material may be, but is not limited to, 1 cps, 50 cps, 100 cps, 150 cps, 200 cps, 250 cps, 300 cps, 350 cps, 400 cps, 450 cps, 500 cps, 550 cps, 600 cps, 650 cps, 700 cps, 750 cps, 800 cps, 850 cps, 900 cps, 950 cps, 1000 cps, etc.

[0234] In some embodiments, the adhesion between the first protective layer 20 and the first welding portion 13 ranges from level 0 to level 1.

[0235] For example, adhesion refers to the degree to which a coating is firmly bonded to the surface of a coated object through the action of physical and chemical forces. The above-mentioned adhesion level is tested using the cross-cut method of the national standard ISO2409.

[0236] 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.

[0237] FIG12 is a schematic cross-sectional structural diagram of another battery cell provided in some embodiments of the present application, and FIG13 is a schematic partial enlarged structural diagram of point E in FIG12 .

[0238] 12 and 13 , in some embodiments, the end cap 12 further includes a second welding portion 121 electrically connected to the electrode assembly 30 of the battery cell 7. The battery cell 7 further includes a second protective layer 50 covering the surface of the second welding portion 121.

[0239] Illustratively, 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, whereby the end cap 12 and the electrode assembly 30 are welded to form a second weld portion 121 on the end cap 12.

[0240] As described above, the second protective layer 50 covers the surface of the second weld portion 121. In other words, the second protective layer 50 covers the second weld portion 121 from the outside of the end cap 12, isolating the second weld portion 121 from the external environment, thereby isolating moisture and reducing the risk of rust on the second weld portion 121. Furthermore, the second protective layer 50 itself has a certain hardness, which can reduce the risk of scratches or impacts on the second weld portion 121, thereby further improving the reliability of the battery cell 7.

[0241] In some embodiments, the first protective layer 20 and the second protective layer 50 are integrally formed. This simplifies the manufacturing process by eliminating the need for an additional joining process. Furthermore, compared to joining the first protective layer 20 and the second protective layer 50 through an additional joining process, the integral structure provides a stronger connection between the first protective layer 20 and the second protective layer 50.

[0242] In some embodiments, the battery cell 7 further includes a current collector 60 . The current collector 60 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 .

[0243] Exemplarily, the current collecting piece 60 is arranged between the electrode assembly 30 and the end cover 12. The end cover 12, the current collecting piece 60 and the electrode assembly 30 are connected by welding to form a second welding portion 121 to achieve electrical connection between the end cover 12, the current collecting piece 60 and the electrode assembly 30. The current collecting piece 60 can improve the stability of the electrical connection between the electrode assembly 30 and the end cover 12.

[0244] According to some embodiments of the present application, the present application further provides a battery, comprising a battery cell 7 according to any of the above solutions.

[0245] 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 solutions, wherein the battery cell 7 is used to provide electrical energy.

[0246] 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.

[0247] The present embodiment provides a battery cell 7, which includes a housing 10, an electrode assembly 30, a first protective layer 20, and an insulating member 40. The electrode assembly 30 is housed in the housing 10. The housing 10 includes a shell 11 and an end cap 12. The shell 11 has an opening 111 and includes a sidewall 112 surrounding the electrode assembly 30. The sidewall 112 is provided with a recess 1121, which is recessed relative to the outer surface of the sidewall 112. The end cap 12 covers the opening 111 and is welded to the bottom wall of the recess 1121 to form a first weld 13. The first protective layer 20 includes a first connecting segment 21, a main segment 22, and a second connecting segment 23, with the main segment 22 located between the first connecting segment 21 and the second connecting segment 23. The first connecting segment 21 is connected to the side of the sidewall 112 facing away from the electrode assembly 30, and the second connecting segment 23 is connected to the side of the end cap 12 facing away from the electrode assembly 30. The main segment 22 covers the surface of the first weld 13. The insulating member 40 is connected to a side of the sidewall 112 facing away from the electrode assembly 30 .

[0248] 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.

[0249] The above technical solution provides the first protective layer 20 , which 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 .

[0250] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0251] 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 make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions 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, comprising: 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, wherein: 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, wherein: 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, wherein: 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, wherein: The first connecting section is spaced apart from the insulating member.

6. The battery cell according to claim 4 or 5, wherein: 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, wherein: 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 any one of claims 4 to 7, wherein: 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 any one of claims 4 to 8, wherein: The first protective layer and the insulating member are an integrally formed structure.

10. The battery cell according to any one of claims 3 to 9, wherein: 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, wherein: 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, wherein: 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 any one of claims 2 to 12, wherein: 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 own extending 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, wherein: 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 any one of claims 1 to 14, wherein: 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, wherein: The thickness d1 of the coating satisfies the relationship: 0.1 μm≤d1≤10 μm.

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

18. The battery cell according to any one of claims 1 to 17, wherein: 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, wherein: The transition surface is an arc surface.

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

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

22. The battery cell according to any one of claims 1 to 21, wherein: The thickness d2 of the first protective layer satisfies the relationship: d2 ≥ 5 μm.

23. The battery cell according to claim 22, wherein: The thickness d2 of the first protective layer satisfies the relationship: d2 ≥ 10 μm.

24. The battery cell according to any one of claims 1 to 23, wherein: The first protective layer is a transparent structure.

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

26. The battery cell according to any one of claims 1 to 25, wherein: The first protective layer includes a coating material, and the coating material includes polyacrylate, polyurethane or epoxy resin.

27. The battery cell according to claim 26, wherein: The viscosity η of the coating material satisfies the relationship: 1cps≤η≤2000cps.

28. The battery cell according to claim 27, wherein: The viscosity η of the coating material satisfies the relationship: 1cps≤η≤1000cps.

29. The battery cell according to any one of claims 1 to 28, wherein: 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 any one of claims 1 to 29, wherein: 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, wherein: 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, wherein: The battery cell is a cylindrical battery cell.

33. A battery comprising the battery cell according to any one of claims 1 to 32.

34. An electrical device, comprising a battery cell as claimed in any one of claims 1 to 32, wherein the battery cell is used to provide electrical energy.

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