Battery cell, manufacturing method and manufacturing system thereof, battery and electric device

Abstract

The embodiments of the present application provide a battery cell and its manufacturing method and manufacturing system, a battery, and an electrical device. The battery cell of the embodiments of the present application includes: a shell having an opening; an electrode assembly housed in the shell; and an end cover for covering the opening, the end cover including a cover body and a convex portion surrounding the outside of the cover body, the convex portion protruding from the inner surface of the cover body in a direction facing the electrode assembly, and at least a portion of the convex portion is located in the shell and is used to cooperate with the shell. A recess is formed on the end cover at a position corresponding to the convex portion, the recess is recessed from the outer surface of the cover body in a direction facing the electrode assembly, and is used to release stress during the process of the convex portion extending into the shell. The present application can improve the assembly efficiency of the battery cell and enhance the safety of the battery cell.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and more particularly, to a battery cell and a manufacturing method and system thereof, a battery, and an electrical device. Background Art

[0002] Battery cells are widely used in electronic devices such as mobile phones, laptops, electric bicycles, electric cars, electric airplanes, electric boats, electric toy cars, electric toy boats, electric toy airplanes, and power tools. Battery cells can include nickel-cadmium battery cells, nickel-metal hydride battery cells, lithium-ion battery cells, and secondary alkaline zinc-manganese battery cells.

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

[0004] The present application provides a battery cell and a manufacturing method and system thereof, a battery, and an electrical device, which can improve the assembly efficiency of the battery cell and enhance the safety of the battery cell.

[0005] In a first aspect, an embodiment of the present application provides a battery cell, comprising:

[0006] a housing having an opening;

[0007] an electrode assembly housed in the housing; and

[0008] an end cap for covering the opening, the end cap comprising a cap body and a protrusion surrounding the outside of the cap body, the protrusion protruding from the inner surface of the cap body in a direction facing the electrode assembly, and at least a portion of the protrusion being located within the housing and adapted to cooperate with the housing;

[0009] A recess is formed on the end cover at a position corresponding to the convex portion. The recess is recessed from the outer surface of the cover body in a direction facing the electrode assembly and is used to release stress when the convex portion extends into the shell.

[0010] In the above solution, the protrusion can extend into the shell during assembly of the end cap and shell, and cooperate with the shell to define the position of the end cap, thereby reducing the difficulty of positioning the shell and end cap and improving the assembly efficiency of the battery cell. The shell can define the position of the end cap through the protrusion, which can reduce the offset and misalignment between the end cap and shell during the connection process, thereby improving the sealing performance. The recess can reduce the strength of the protrusion. In this way, when the protrusion and shell are squeezed against each other, the protrusion can release stress through deformation, reducing the squeezing force and friction between the protrusion and shell, reducing the generation of particles, reducing the risk of shell deformation, and improving the safety performance of the battery cell.

[0011] In some embodiments, in the thickness direction of the end cap, the bottom surface of the recess is closer to the electrode assembly than the inner surface of the cap body.

[0012] The above scheme can ensure the depth of the first recess to increase the degree to which the convex portion protrudes from the inner surface of the cover body, thereby improving the matching effect between the convex portion and the shell, increasing the elasticity of the convex portion, reducing the extrusion force and friction force between the convex portion and the shell, reducing the generated particles, reducing the risk of shell deformation, and improving the safety performance of the battery cell.

[0013] In some embodiments, the side wall of the shell extends along the thickness direction of the end cover and is arranged around the periphery of the electrode assembly. The inner wall surface of the side wall and the outer peripheral surface of the protrusion are both parallel to the thickness direction and are arranged opposite to each other.

[0014] In the above scheme, the inner wall surface of the side wall and the outer peripheral surface of the convex portion are arranged in parallel. In this way, when the inner wall surface of the side wall and the outer peripheral surface of the convex portion contact and squeeze each other, the force between the two is relatively uniform, thereby reducing stress concentration and reducing deformation of the shell and the convex portion.

[0015] In some embodiments, the side wall of the housing and the protrusion are interference fit so that the inner wall surface of the side wall and the outer peripheral surface of the protrusion abut against each other.

[0016] In the above solution, the interference fit can increase the connection strength between the housing and the end cap, improving the sealing performance. This solution reduces the strength of the protrusion by providing a recess, thereby reducing the force between the protrusion and the housing during its insertion. This reduces the generation of particles, even when the housing and the protrusion have an interference fit, and reduces the risk of housing deformation, thereby improving the safety performance of the battery cell.

[0017] In some embodiments, the inner wall surface of the side wall is welded to the outer peripheral surface of the protrusion to form a first welding portion. In the thickness direction, the first welding portion does not extend beyond the outer surface of the cover body in a direction away from the electrode assembly.

[0018] In the above solution, the cover body serves as the load-bearing structure for the battery cell. After the battery cell is installed in the electrical device, the external support structure can support the battery cell through the cover body. This solution ensures that the first weld does not extend beyond the outer surface of the cover body in the direction away from the electrode assembly. This reduces the force between the external support structure and the first weld, lowering the risk of cracking the first weld, and ensuring the connection strength and sealing performance between the housing and the end cap.

[0019] In some embodiments, the sidewall includes a first outer end surface surrounding the opening, the first outer end surface being connected to the inner wall surface of the sidewall. In the thickness direction, the protrusion has a second outer end surface at an end facing away from the electrode assembly, the second outer end surface being connected to the outer peripheral surface of the protrusion, the first outer end surface and the second outer end surface being flush, and the first outer end surface and the second outer end surface being closer to the electrode assembly than the outer surface of the cover body.

[0020] The above scheme makes the first outer end face and the second outer end face closer to the electrode assembly than the outer surface of the cover body. In this way, even if the first welding portion protrudes from the first outer end face and the second outer end face, the first welding portion can not exceed the outer surface of the cover body in the direction away from the electrode assembly, thereby reducing the force acting on the first welding portion, reducing the risk of rupture of the first welding portion, and ensuring the connection strength and sealing performance between the shell and the end cover.

[0021] In some embodiments, the shell further includes a flange portion, which is connected to the side wall and bent relative to the side wall toward the cover body to cover the first welding portion.

[0022] In the above solution, the flange portion can protect the first welding portion, reduce the risk of the first welding portion being corroded or damaged, and ensure the connection strength and sealing performance between the shell and the end cover.

[0023] In some embodiments, the end cover further includes an extension portion protruding from the outer peripheral surface of the protrusion and surrounding the outside of the protrusion, and the inner surface of the extension portion is welded to the first outer end surface of the side wall surrounding the opening to connect the shell and the end cover as one.

[0024] In the above solution, when assembling the end cover and the shell, the first outer end surface can play the role of limiting the position of the end cover in the thickness direction, reducing the risk of the end cover being over-inserted into the shell and improving assembly efficiency.

[0025] In some embodiments, the protrusion and the housing are clearance-matched to form a gap between an outer peripheral surface of the protrusion and an inner wall surface of the side wall.

[0026] In the above scheme, the clearance fit can not only ensure that the shell limits the protrusion, but also reduce the force between the protrusion and the shell during the process of the protrusion extending into the shell, reduce the risk of friction between the protrusion and the shell, reduce the generated particles and reduce the deformation of the shell, and improve the safety performance of the battery cell.

[0027] In some embodiments, in the direction from the electrode assembly to the side wall, the size of the gap between the outer peripheral surface of the protrusion and the inner wall surface of the side wall is 0.02 mm-0.5 mm.

[0028] In the above solution, the smaller the gap, the higher the risk of friction between the outer peripheral surface of the protrusion and the inner surface of the sidewall, and the higher the risk of particle generation. The larger the gap, the greater the range of motion of the protrusion after it extends into the shell, and the higher the risk of poor welding between the extension and the shell. The inventors set the gap size to 0.02mm-0.5mm to balance risks and improve safety.

[0029] In some embodiments, an inner surface of the extension portion is provided with an avoidance groove, which surrounds the outer side of the convex portion, and a groove wall surface of the avoidance groove is used to connect the inner surface of the extension portion and the outer peripheral surface of the convex portion.

[0030] In the above solution, a rounded corner is provided at the junction of the convex portion and the extension portion during the molding process to reduce stress concentration. In this solution, a relief groove is provided on the extension portion, and the portion of the extension portion opposite the relief groove is connected to the convex portion. The relief groove is recessed to provide space for material flow during the molding process. Thus, a rounded corner is formed at the portion of the extension portion opposite the relief groove, and the surface of the rounded corner forms part of the relief groove wall. The groove wall is recessed relative to the inner surface of the extension portion. Therefore, this embodiment ensures that the first outer end face smoothly abuts the inner surface of the extension portion, preventing the rounded corner from interfering with the first outer end face.

[0031] In some embodiments, an outer surface of the extension is flush with an outer surface of the cover body.

[0032] In the above solution, the external support structure can support the battery cell through the extension portion and the cover body, which can increase the area of ​​the load-bearing portion of the end cover and improve the stability of the battery cell.

[0033] In some embodiments, in a direction from the electrode assembly to the side wall, the extension portion does not exceed the outer wall surface of the side wall.

[0034] The above solution can avoid the extension portion increasing the maximum size of the battery cell, thereby ensuring the energy density of the battery cell. In addition, the end cap is relatively thin, and if the extension portion exceeds the outer wall surface of the side wall, it may scratch other external components.

[0035] In some embodiments, in the direction from the electrode assembly to the side wall, the outer wall surface of the side wall extends beyond the extension portion by 0.02 mm to 0.5 mm.

[0036] In the above solution, the smaller the outer surface of the side wall protrudes beyond the extension, the higher the risk that the second welded portion formed by welding the side wall and the extension will protrude beyond the outer surface of the side wall. The larger the outer surface of the side wall protrudes beyond the extension, the smaller the connection area between the extension and the side wall, and the lower the connection strength between the extension and the side wall. The inventors set the outer surface of the side wall protruding beyond the extension to 0.02 mm to 0.5 mm, minimizing the risk of the second welded portion protruding beyond the outer surface of the side wall while ensuring connection strength.

[0037] In some embodiments, in a direction from the electrode assembly to the side wall, a dimension of an outer peripheral surface of the extension protruding from the convex portion is smaller than a thickness of the side wall.

[0038] In the above solution, when the outer peripheral surface of the protrusion abuts against the inner wall surface of the side wall, since the wall thickness of the side wall is greater than the dimension of the outer peripheral surface of the extension protruding from the protrusion, the outer wall surface of the side wall exceeds the extension in the direction of the electrode assembly pointing to the side wall.

[0039] In some embodiments, the protrusion also includes a guide surface facing the side wall, the guide surface is connected to the end of the outer peripheral surface of the protrusion close to the electrode assembly, and the guide surface is inclined toward the inner wall surface away from the side wall compared to the outer peripheral surface of the protrusion to guide the protrusion into the shell.

[0040] In the above solution, by providing an inclined guide surface on the protrusion, the protrusion can be guided to be inserted into the shell when assembling the end cover and the shell, thereby simplifying the assembly process and improving assembly efficiency.

[0041] In some embodiments, the protrusion abuts against the first tab of the electrode assembly to support the first tab.

[0042] In the above solution, the protrusion can support the first electrode tab to reduce the shaking amplitude of the electrode assembly when the battery cell vibrates, thereby improving the stability of the electrode assembly.

[0043] In some embodiments, the protrusion is welded to the first electrode tab to electrically connect the first electrode tab and the end cap.

[0044] In the above solution, the convex portion is directly welded to the first tab, eliminating the need for additional transition components, thereby simplifying the battery cell structure. This solution reduces the thickness of the convex portion by providing a recessed portion. This reduces the welding power required to weld the convex portion to the first tab, lowering heat generation and minimizing the risk of burns to other components.

[0045] In some embodiments, the first tab of the electrode assembly is electrically connected to the housing through an end cap.

[0046] In the above solution, the housing is connected to the first tab of the electrode assembly via an end cap, ensuring that the potential of the housing is substantially the same as that of the first tab. This allows the housing itself to serve as the output terminal of the battery cell, eliminating a traditional electrode terminal and simplifying the battery cell structure. When multiple battery cells are assembled into a group, the housing can be electrically connected to the current collector, which not only increases the flow area but also allows for more flexible design of the collector structure.

[0047] In some embodiments, the housing includes a sidewall and a bottom wall. The sidewall extends along the thickness of the end cap and surrounds the periphery of the electrode assembly. The bottom wall is connected to one end of the sidewall and is located on the side of the electrode assembly facing away from the end cap. The bottom wall is provided with an electrode lead-out hole. The electrode assembly is provided with a second tab at the end facing the bottom wall. The first and second tabs have opposite polarities. The battery cell also includes an electrode terminal mounted in the electrode lead-out hole, the electrode terminal being electrically connected to the second tab.

[0048] In the above solution, the bottom wall and electrode terminals can serve as the two output poles of the battery cell, which can simplify the battery cell structure and ensure the battery cell's current capacity. The bottom wall and electrode terminals are located at the same end of the battery cell. In this way, the current collecting component can be assembled on the same side of the battery cell, which can simplify the assembly process and improve the efficiency of assembling multiple battery cells into groups.

[0049] In some embodiments, the bottom wall and the side walls are integrally formed structures.

[0050] The above solution can save the process of connecting the bottom wall and the side wall and reduce the resistance between the two.

[0051] In some embodiments, the first electrode tab is a negative electrode tab, and the base material of the shell is steel.

[0052] In the above solution, the housing is electrically connected to the negative electrode tab, meaning the housing is in a low-potential state. The steel housing is less susceptible to corrosion by the electrolyte in this low-potential state, thus reducing safety risks.

[0053] In some embodiments, the battery cells are cylindrical battery cells.

[0054] In a second aspect, an embodiment of the present application provides a battery comprising a plurality of battery cells according to any one of the embodiments of the first aspect.

[0055] In a third aspect, an embodiment of the present application provides an electrical device, comprising the battery of the second aspect, the battery being used to provide electrical energy.

[0056] In a fourth aspect, an embodiment of the present application provides a method for manufacturing a battery cell, comprising:

[0057] providing a housing having an opening;

[0058] Providing an electrode assembly and installing the electrode assembly into the housing;

[0059] An end cap is provided, comprising a cap body and a convex portion surrounding the outer side of the cap body, the convex portion protruding from the inner surface of the cap body, a concave portion being formed on the end cap at a position corresponding to the convex portion, and the concave portion being recessed from the outer surface of the cap body;

[0060] Extending at least a portion of the protrusion into the housing and adapted to engage with the housing;

[0061] Connecting the end cover and the housing so that the end cover covers the opening;

[0062] The convex portion protrudes from the inner surface of the cover body in the direction facing the electrode assembly, the concave portion is recessed from the outer surface of the cover body in the direction facing the electrode assembly, and the concave portion is used to release stress when the convex portion extends into the shell.

[0063] In a fifth aspect, an embodiment of the present application provides a battery cell manufacturing system, comprising:

[0064] A first providing device is used to provide a housing having an opening;

[0065] a second providing device for providing an electrode assembly and installing the electrode assembly into the housing;

[0066] A third providing device is used to provide an end cap, the end cap comprising a cap body and a convex portion surrounding the outer side of the cap body, the convex portion protruding from the inner surface of the cap body, a concave portion formed on the end cap at a position corresponding to the convex portion, the concave portion being recessed from the outer surface of the cap body;

[0067] a first assembly device for extending at least a portion of the protrusion into the housing and for mating with the housing;

[0068] a second assembly device for connecting the end cap and the housing so that the end cap covers the opening;

[0069] The convex portion protrudes from the inner surface of the cover body in the direction facing the electrode assembly, the concave portion is recessed from the outer surface of the cover body in the direction facing the electrode assembly, and the concave portion is used to release stress when the convex portion extends into the shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0071] Figure 1 A schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0072] Figure 2 An exploded schematic diagram of a battery provided in some embodiments of the present application;

[0073] Figure 3 for Figure 2 An exploded schematic diagram of the battery module shown;

[0074] Figure 4 An exploded schematic diagram of a battery cell provided in some embodiments of the present application;

[0075] Figure 5 A schematic cross-sectional view of a battery cell provided in some embodiments of the present application;

[0076] Figure 6 for Figure 5 An enlarged schematic diagram of a battery cell at circle A is shown;

[0077] Figure 7 Schematic cross-sectional views of battery cells provided in other embodiments of the present application;

[0078] Figure 8 A schematic cross-sectional view of a battery cell provided in some other embodiments of the present application;

[0079] Figure 9 for Figure 8 An enlarged schematic diagram of a battery cell shown at circle B;

[0080] Figure 10 for Figure 9 An enlarged schematic diagram at box C;

[0081] Figure 11 A schematic flow chart of a method for manufacturing a battery cell according to some embodiments of the present application;

[0082] Figure 12 A schematic block diagram of a battery cell manufacturing system provided in some embodiments of the present application.

[0083] In the drawings, the drawings are not drawn to scale. DETAILED DESCRIPTION

[0084] 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 described below in conjunction with the 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.

[0085] 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 for the purpose of describing specific embodiments only 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] The term "plurality" used in this application refers to two or more (including two).

[0091] 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.

[0092] The battery referred to in the embodiments of this application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in this application may include a battery module or a battery pack. A battery generally includes a casing that encloses one or more battery cells. The casing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0093] A battery cell includes an electrode assembly and an electrolyte. The electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator. A battery cell primarily operates by the movement of metal ions between the positive and negative electrode sheets. The positive electrode sheet includes a positive current collector and a positive active material layer, with the positive active material layer coated on the surface of the positive current collector. The positive current collector includes a positive current collector portion and a positive electrode tab connected to the positive current collector portion. The positive current collector portion is coated with the positive active material layer, while the positive electrode tab is not coated with the positive active material layer. Taking a lithium-ion battery as an example, the material of the positive current collector can be aluminum, and the positive active material layer includes a positive active material. The positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode sheet includes a negative current collector and a negative active material layer, which is coated on the surface of the current collector. The negative current collector includes a negative current collecting portion and a negative electrode tab connected to the negative current collecting portion. The negative current collecting portion is coated with the negative active material layer, while the negative tab is not coated with the negative active material layer. The negative current collector can be made of copper, and the negative active material layer includes a negative active material, which can be carbon or silicon, for example. The separator can be made of materials such as PP (polypropylene) or PE (polyethylene).

[0094] The battery cell further includes a housing and an end cap. The housing has an opening and is used to accommodate the electrode assembly. The electrode assembly can be assembled into the housing through the opening of the housing. The end cap is used to cover the opening of the housing to achieve sealing.

[0095] In the related art, when assembling the end cap and the housing, the end cap is typically pressed against the open end of the housing and then connected to the housing through welding or other methods. However, the inventors discovered that during the pressing process, the housing and the end cap cannot be restrained by each other, which increases the difficulty of positioning the housing and the end cap in the equipment and reduces the efficiency of battery cell assembly. In addition, during the connection process, the end cap and the housing are prone to offset and misalignment, affecting the sealing performance.

[0096] The inventors discovered that a convex portion could be provided on the end cap. This convex portion could be inserted into the housing during assembly and cooperate with the housing to define the position of the end cap. This convex portion can reduce the difficulty of positioning the housing and end cap, improve battery cell assembly efficiency, and reduce offset and misalignment between the end cap and housing during connection, thereby improving sealing performance.

[0097] However, the inventors further discovered that the protrusions, when inserted into the casing, can press against the inner surface of the casing. Friction between the protrusions and the casing can form particles, which can fall into the electrode assembly and potentially connect the positive and negative electrodes, posing a safety risk. Furthermore, excessive pressure between the protrusions and the casing can cause the casing to deform, affecting its appearance and the sealing of the battery cells.

[0098] In view of this, the embodiments of the present application provide a technical solution that forms a first recess on the end cap at a position corresponding to the protrusion to relieve stress as the protrusion extends into the housing. The first recess can reduce the strength of the protrusion. Thus, when the protrusion presses against the inner surface of the housing, the protrusion can release stress through deformation, reducing the squeezing force and friction between the protrusion and the housing, reducing the generation of particles, reducing the risk of housing deformation, and improving the safety performance of the battery cell.

[0099] The technical solutions described in the embodiments of the present application are applicable to batteries and electrical devices using batteries.

[0100] Electrical devices may include vehicles, mobile phones, portable devices, laptop computers, ships, spacecraft, electric toys, and electric tools, etc. Vehicles may include fuel vehicles, gas vehicles, or new energy vehicles. New energy vehicles may include pure electric vehicles, hybrid vehicles, or extended-range vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Electric tools include 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. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical devices.

[0101] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device.

[0102] Figure 1 A schematic structural diagram of a vehicle provided for some embodiments of the present application.

[0103] like Figure 1As shown, a battery 2 is provided inside the vehicle 1, and the battery 2 can be provided at the bottom, head, or tail of the vehicle 1. The battery 2 can be used to power the vehicle 1, for example, the battery 2 can serve as an operating power source for the vehicle 1.

[0104] 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.

[0105] 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.

[0106] Figure 2 Schematic diagram of an explosion of a battery provided in some embodiments of the present application.

[0107] like Figure 2 As shown, the battery 2 includes a box 5 and a battery cell ( Figure 2 The battery cells are housed in the box body 5 .

[0108] The housing 5 is used to house battery cells and can have various structures. In some embodiments, the housing 5 can include a first housing portion 5a and a second housing portion 5b. The first housing portion 5a and the second housing portion 5b overlap each other, and the first housing portion 5a and the second housing portion 5b together define a storage space 5c for accommodating the battery cells. The second housing portion 5b can be a hollow structure with one end open. The first housing portion 5a is a plate-like structure, and the first housing portion 5a overlaps the open side of the second housing portion 5b to form the housing 5 with the storage space 5c. The first housing portion 5a and the second housing portion 5b can also be hollow structures with one end open. The open side of the first housing portion 5a overlaps the open side of the second housing portion 5b to form the housing 5 with the storage space 5c. Of course, the first housing portion 5a and the second housing portion 5b can have various shapes, such as a cylinder, a rectangular parallelepiped, etc.

[0109] In order to improve the sealing performance after the first box body 5a and the second box body 5b are connected, a sealing member, such as a sealant, a sealing ring, etc., may also be provided between the first box body 5a and the second box body 5b.

[0110] Assuming that the first box body portion 5a covers the top of the second box body portion 5b, the first box body portion 5a can also be called an upper box cover, and the second box body portion 5b can also be called a lower box body.

[0111] In battery 2, there can be one or more battery cells. If there are multiple battery cells, they can be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration refers to a combination of series and parallel connections. Multiple battery cells can be directly connected in series, in parallel, or in a hybrid configuration, and then the entire battery module can be housed within housing 5. Alternatively, multiple battery cells can be first connected in series, in parallel, or in a hybrid configuration to form a battery module 6, and then multiple battery modules 6 can be connected in series, in parallel, or in a hybrid configuration to form a single unit housed within housing 5.

[0112] Figure 3 for Figure 2 An exploded diagram of the battery module is shown.

[0113] In some embodiments, as Figure 3 As shown, there are multiple battery cells 7, which are first connected in series, in parallel, or in mixed series to form a battery module 6. The multiple battery modules 6 are then connected in series, in parallel, or in mixed series to form a whole, which is accommodated in a box.

[0114] The multiple battery cells 7 in the battery module 6 can be electrically connected via a busbar component to achieve parallel connection, series connection, or mixed connection of the multiple battery cells 7 in the battery module 6 .

[0115] Figure 4 An exploded schematic diagram of a battery cell provided in some embodiments of the present application; Figure 5 A schematic cross-sectional view of a battery cell provided in some embodiments of the present application; Figure 6 for Figure 5 An enlarged schematic diagram of a battery cell at circle A is shown.

[0116] like Figures 4 to 6 As shown, the battery cell 7 of the embodiment of the present application includes: a housing 20 having an opening 21; an electrode assembly 10 accommodated within the housing 20; and an end cap 30 for covering the opening 21. The end cap 30 includes a cap body 31 and a protrusion 32 surrounding the outside of the cap body 31. The protrusion 32 protrudes from the inner surface 311 of the cap body in a direction facing the electrode assembly 10, and at least a portion of the protrusion 32 is located within the housing 20 and is configured to cooperate with the housing 20. A recess 33 is formed on the end cap 30 at a position corresponding to the protrusion 32. The recess 33 is recessed from the outer surface 312 of the cap body in a direction facing the electrode assembly 10 and is configured to relieve stress during the process of the protrusion 32 extending into the housing 20.

[0117] The electrode assembly 10 includes a first electrode plate, a second electrode plate, and a separator, wherein the separator is used to separate the first electrode plate and the second electrode plate. The polarity of the first electrode plate and the second electrode plate are opposite. In other words, one of the first electrode plate and the second electrode plate is a positive electrode plate, and the other of the first electrode plate and the second electrode plate is a negative electrode plate.

[0118] Optionally, the first pole piece, the second pole piece and the separator are all strip-shaped structures, and the first pole piece, the second pole piece and the separator are wound together to form a wound structure. The wound structure can be a cylindrical structure, a flat structure or a structure of other shapes.

[0119] The shell 20 is a hollow structure with one side open. The end cap 30 covers the opening of the shell 20 and forms a sealed connection to form a receiving cavity for accommodating the electrode assembly 10 and the electrolyte.

[0120] The housing 20 is a hollow structure, forming a space within it for accommodating the electrode assembly 10. The housing 20 can have various shapes, such as a cylinder or a rectangular parallelepiped. The shape of the housing 20 can be determined based on the specific shape of the electrode assembly 10. For example, if the electrode assembly 10 has a cylindrical structure, a cylindrical housing can be used; if the electrode assembly 10 has a rectangular parallelepiped structure, a rectangular parallelepiped housing can be used.

[0121] The shell 20 can be positively charged, negatively charged, or uncharged. When the shell 20 needs to be charged, the shell 20 can be directly connected to the electrode piece of the electrode assembly 10, or can be electrically connected to the electrode piece through other conductive components.

[0122] Optionally, the end cap 30 and the housing 20 can be connected by welding, so that the end cap 30 and the housing 20 have substantially the same electrical potential. For example, when the housing 20 needs to be positively charged, the end cap 30 can be used to electrically connect the housing 20 to the positive polarity electrode; when the housing 20 needs to be negatively charged, the end cap 30 can be used to electrically connect the housing 20 to the negative polarity electrode. Of course, the housing 20 can also be connected to the electrode via other conductive structures, and this embodiment is not limited to this.

[0123] The end cap 30 can be electrically connected to the electrode assembly 10 or insulated from the electrode assembly 10. Optionally, the end cap 30 is electrically connected to the first electrode sheet. Of course, the end cap 30 can be directly electrically connected to the first electrode sheet or electrically connected to the first electrode sheet through other components.

[0124] The housing 20 and the end cover 30 may be made of the same material or different materials.

[0125] The cover body 31 is a plate-like structure having an inner surface and an outer surface disposed opposite each other along the thickness direction Z. The inner surface 311 of the cover body faces the electrode assembly 10. Alternatively, the cover body 31 is a flat plate, and the inner surface 311 and the outer surface 312 of the cover body are both planar and parallel.

[0126] The protrusion 32 is an annular structure surrounding the outer side of the cover body 31 .

[0127] The protrusion 32 protrudes relative to the inner surface 311 of the cover body in a direction facing the electrode assembly 10, so that at least a portion of the protrusion 32 protrudes from the inner surface 311 of the cover body. The protrusion 32 can extend entirely into the housing 20, or only partially into the housing 20, which is not limited in this embodiment.

[0128] The portion of the protrusion 32 extending into the housing 20 may have an interference fit, a clearance fit, or a transition fit with the housing 20 , which is not limited in this embodiment.

[0129] The position of the recess 33 corresponds to the position of the protrusion 32, and the recess 33 is recessed relative to the outer surface 312 of the cover body in the direction facing the electrode assembly 10. The recess 33 can reduce the strength of the protrusion 32, so that the area on the end cover 30 corresponding to the protrusion 32 has better elasticity.

[0130] In this embodiment, the protrusion 32 can extend into the shell 20 when assembling the end cap 30 and the shell 20, and cooperate with the shell 20 to define the position of the end cap 30, thereby reducing the difficulty of positioning the shell 20 and the end cap 30 and improving the assembly efficiency of the battery cell 7. The shell 20 can define the position of the end cap 30 through the protrusion 32, which can reduce the offset and misalignment between the end cap 30 and the shell 20 during the connection process, thereby improving the sealing performance. The recess 33 can reduce the strength of the protrusion 32. In this way, when the protrusion 32 and the shell 20 are squeezed against each other, the protrusion 32 can release stress through deformation, reducing the squeezing force and friction between the protrusion 32 and the shell 20, reducing the generated particles, reducing the risk of deformation of the shell 20, and improving the safety performance of the battery cell 7.

[0131] In some embodiments, in the thickness direction Z of the end cap 30 , the bottom surface of the recess 33 is closer to the electrode assembly 10 as a whole than the inner surface 311 of the cap body.

[0132] This embodiment can ensure the depth of the first recess 33 to increase the degree to which the protrusion 32 protrudes from the inner surface 311 of the cover body, thereby improving the matching effect between the protrusion 32 and the shell 20, and increasing the elasticity of the protrusion 32 to reduce the extrusion force and friction between the protrusion 32 and the shell 20, reduce the generated particles, reduce the risk of deformation of the shell 20, and improve the safety performance of the battery cell 7.

[0133] In some embodiments, the cover body 31 may be an annular flat plate structure, and the end cover 30 may further include a portion surrounded by the cover body 31 .

[0134] In some embodiments, the housing 20 is welded to the end cap 30. Welding can not only achieve the connection between the housing 20 and the end cap 30, but also ensure the sealing.

[0135] In some embodiments, the electrode assembly 10 includes a main body 11, a first electrode tab 12, and a second electrode tab 13. The first electrode tab 12 and the second electrode tab 13 protrude from the main body 11. The first electrode tab 12 is the portion of the first electrode sheet not coated with the active material layer, and the second electrode tab is the portion of the second electrode sheet not coated with the active material layer. Accordingly, one of the first electrode tab 12 and the second electrode tab 13 is a positive polarity tab, and the other is a negative polarity tab.

[0136] The first electrode tab 12 and the second electrode tab 13 may extend from the same side of the main body 11 , or may extend from opposite sides thereof.

[0137] Exemplarily, the first electrode tab 12 and the second electrode tab 13 are respectively provided on both sides of the main body 11. In other words, the first electrode tab 12 and the second electrode tab 13 are respectively provided at both ends of the electrode assembly 10. Optionally, the first electrode tab 12 is located at the end of the electrode assembly 10 facing the end cap 30, and the second electrode tab 13 is located at the end of the electrode assembly 10 facing away from the end cap 30.

[0138] Optionally, the first pole tab 12 is wound around the central axis of the electrode assembly 10 in multiple turns. In other words, the first pole tab 12 includes multiple turns of pole tab layers. After the winding is completed, the first pole tab 12 is generally cylindrical, and a gap is left between two adjacent turns of pole tab layers. The embodiment of the present application can process the first pole tab 12 to reduce the gap between the pole tab layers, so as to facilitate the connection of the first pole tab 12 with other conductive structures. For example, the embodiment of the present application can flatten the first pole tab 12 so that the end area of ​​the first pole tab 12 away from the main body 11 is gathered and gathered together; the flattening process forms a dense end face at the end of the first pole tab 12 away from the main body 11, reduces the gap between the pole tab layers, and facilitates the connection of the first pole tab 12 with other conductive structures. Alternatively, the embodiment of the present application can also fill the conductive material between two adjacent turns of pole tab layers to reduce the gap between the pole tab layers.

[0139] Optionally, the second electrode tab 13 is wound multiple times around the central axis of the electrode assembly 10, and the second electrode tab 13 includes multiple electrode tab layers. Exemplarily, the second electrode tab 13 is also flattened to reduce gaps between the electrode tab layers of the second electrode tab 13.

[0140] In some embodiments, a first electrode tab 12 is provided at one end of the electrode assembly 10 facing the end cap 30 , and the first electrode tab 12 is electrically connected to the end cap 30 .

[0141] The end cap 30 may be directly connected to the first electrode tab 12. For example, the end cap 30 may be directly welded to the first electrode tab 12 to achieve electrical connection between the end cap 30 and the first electrode tab 12. Alternatively, the end cap 30 may be indirectly connected to the first electrode tab 12 via other conductive structures (such as the current collecting member 50).

[0142] In this embodiment, the potential of the end cap 30 can be substantially the same as that of the first tab 12 . Thus, the end cap 30 can serve as the output terminal of the battery cell 7 , thereby eliminating a traditional electrode terminal and simplifying the structure of the battery cell 7 .

[0143] In some embodiments, the first tab 12 of the electrode assembly 10 is electrically connected to the housing 20 through the end cap 30 .

[0144] In this embodiment, the housing 20 is connected to the first tab 12 of the electrode assembly 10 via the end cap 30 so that the potential of the housing 20 is substantially the same as that of the first tab 12. Thus, the housing 20 itself can serve as the output terminal of the battery cell 7, thereby eliminating a traditional electrode terminal and simplifying the structure of the battery cell 7. When multiple battery cells 7 are assembled into a group, the housing 20 can be electrically connected to the busbar, which not only increases the flow area but also makes the structural design of the busbar more flexible.

[0145] In some embodiments, the housing 20 includes a sidewall 22 and a bottom wall 23. The sidewall 22 extends along the thickness direction Z of the end cap 30 and surrounds the periphery of the electrode assembly 10. The bottom wall 23 is connected to one end of the sidewall 22 and is located on the side of the electrode assembly 10 facing away from the end cap 30. The bottom wall 23 is provided with an electrode lead-out hole 231. The electrode assembly 10 is provided with a second electrode tab 13 at the end facing the bottom wall 23. The first electrode tab 12 and the second electrode tab 13 have opposite polarities. The battery cell 7 also includes an electrode terminal 40 mounted in the electrode lead-out hole 231. The electrode terminal 40 is electrically connected to the second electrode tab 13.

[0146] The sidewall 22 and the bottom wall 23 can be an integrally formed structure, that is, the housing 20 is an integrally formed component. Of course, the sidewall 22 and the bottom wall 23 can also be two components provided separately, and then connected together by welding, riveting, bonding, etc.

[0147] The side wall 22 is a cylindrical structure, for example, a circular cylinder or a square cylinder; the bottom wall 23 is a plate-like structure, and its shape corresponds to the shape of the side wall 22. Optionally, one end of the side wall 22 forms an opening 21, and the bottom wall 23 is connected to the other end of the side wall 22 facing away from the opening 21.

[0148] The second electrode tab 13 may be directly electrically connected to the electrode terminal 40 , or may be indirectly electrically connected to the electrode terminal 40 through other conductive structures.

[0149] The electrode terminal 40 is insulated and disposed on the bottom wall 23. The electrode terminal 40 and the bottom wall 23 may have different polarities and may serve as the two output poles of the battery cell 7. Optionally, the battery cell 7 further includes an insulating member, at least a portion of which is located between the bottom wall 23 and the electrode terminal 40 to insulate and separate the bottom wall 23 and the electrode terminal 40.

[0150] When the first tab 12 is a negative tab and the second tab 13 is a positive tab, the bottom wall 23 is the negative output pole of the battery cell 7, and the electrode terminal 40 is the positive output pole of the battery cell 7. When the first tab 12 is a positive tab and the second tab 13 is a negative tab, the bottom wall 23 is the positive output pole of the battery cell 7, and the electrode terminal 40 is the negative output pole of the battery cell 7.

[0151] The electrode terminal 40 is fixed to the bottom wall 23. The electrode terminal 40 can be fixed as a whole to the outside of the bottom wall 23, or can extend into the interior of the housing 20 through the electrode lead-out hole 231.

[0152] The first electrode tab 12 is located at the end of the electrode assembly 10 facing the end cap 30, so as to facilitate electrical connection between the end cap 30 and the first electrode tab 12. Correspondingly, the second electrode tab 13 is located at the end of the electrode assembly 10 facing the bottom wall 23, so as to facilitate electrical connection between the electrode terminal 40 and the second electrode tab 13. In the embodiment of the present application, the first electrode tab 12 and the second electrode tab 13 are arranged at both ends of the electrode assembly 10, which can reduce the risk of electrical conduction between the first electrode tab 12 and the second electrode tab 13 and increase the flow area of ​​the first electrode tab 12 and the flow area of ​​the second electrode tab 13.

[0153] In this embodiment, the bottom wall 23 and the electrode terminal 40 can serve as the two output poles of the battery cell 7, which can simplify the structure of the battery cell 7 and ensure the current carrying capacity of the battery cell 7. The bottom wall 23 and the electrode terminal 40 are located at the same end of the battery cell 7. In this way, the busbar can be assembled to the same side of the battery cell 7, which can simplify the assembly process and improve the efficiency of assembling multiple battery cells 7 into groups.

[0154] In some embodiments, the bottom wall 23 and the side wall 22 are integrally formed. This embodiment can eliminate the need for connecting the bottom wall 23 and the side wall 22 and reduce the electrical resistance between the two. For example, the housing 20 can be formed by a stretching process.

[0155] The electrode lead-out hole 231 in the embodiment of the present application is formed after the shell 20 is stretched.

[0156] The inventors have tried to roll the open end of the shell so that the open end of the shell is folded inward and forms a flange structure. The flange structure presses the end cover to fix the end cover. The inventors installed the electrode terminal on the end cover and used the flange structure and electrode terminal as the two output poles of the battery cell. However, the larger the size of the flange structure, the higher the risk of curling and wrinkling after forming; if the flange structure curls and wrinkles, it will cause the surface of the flange structure to be uneven, and when the flange structure is welded to the collector component, there will be problems with poor welding. Therefore, the size of the flange structure is relatively limited, resulting in insufficient current capacity of the battery cell.

[0157] In this embodiment, an electrode lead-out hole 231 for mounting the electrode terminal 40 is formed on the bottom wall 23 by a perforation process, thereby positioning the positive and negative output electrodes at the end of the battery cell 7 facing away from the outlet 21. The bottom wall 23 is formed during the molding process of the housing 20. The electrode lead-out hole 231 ensures the flatness of the bottom wall 23 and the connection strength between the bottom wall 23 and the current collector. Furthermore, the flatness of the bottom wall 23 is not constrained by its own dimensions, allowing it to be larger, thereby improving the current handling capacity of the battery cell 7.

[0158] In some embodiments, the first electrode tab 12 is a negative electrode tab, and the base material of the shell 20 is steel.

[0159] The housing 20 is electrically connected to the negative electrode tab, that is, the housing 20 is in a low potential state. The steel housing 20 is not easily corroded by the electrolyte in the low potential state, thereby reducing safety risks.

[0160] In some embodiments, the base material of the housing 20 is the same as the base material of the end cover 30. Optionally, the base material of the housing 20 and the base material of the end cover 30 are both steel.

[0161] In this embodiment, the base material of the housing 20 and the base material of the end cover 30 are the same, which can ensure the welding strength between the housing 20 and the end cover 30 and improve the sealing of the battery cell 7.

[0162] In some embodiments, the battery cell is a cylindrical battery cell. Accordingly, the electrode assembly 10 is a cylindrical structure, and the housing 20 is a cylindrical hollow structure.

[0163] In some embodiments, the protrusion 32 may directly support the first electrode tab 12 or support the first electrode tab 12 through other components.

[0164] In some embodiments, the protrusion 32 abuts against the first electrode tab 12 of the electrode assembly 10 to support the first electrode tab 12 .

[0165] In this embodiment, the protrusion 32 can support the first electrode tab 12 to reduce the shaking amplitude of the electrode assembly 10 when the battery cell 7 vibrates, thereby improving the stability of the electrode assembly 10 .

[0166] In some embodiments, the protrusion is welded to the first electrode tab to electrically connect the first electrode tab and the end cap.

[0167] This embodiment allows the protrusion 32 to be directly welded to the first tab 12 without requiring any additional transition components, thereby simplifying the structure of the battery cell 7. This embodiment reduces the thickness of the protrusion 32 by providing the recess 33. This reduces the welding power required to weld the protrusion 32 to the first tab 12, reduces heat generation, and reduces the risk of burns to other components.

[0168] In some embodiments, the protrusion 32 is configured to cooperate with the housing 20 to define a radial position of the end cover 30 .

[0169] The housing 20 has a central axis, and the sidewalls 22 are arranged around the central axis. The central axis of the housing 20 extends along the thickness direction Z of the end cover 30. In the description of this application, the radial direction is a direction perpendicular to the thickness direction Z and passing through the central axis.

[0170] The radial direction described herein applies to cylindrical battery cells. In a cylindrical battery cell, the electrode assembly 10 is a cylindrical structure, the housing 20 is a cylindrical hollow structure, and the end cap 30 is a circular plate structure. For cylindrical battery cells, the "radial direction" can be the radius of the housing 20.

[0171] Of course, the radial direction described in this application is also applicable to square battery cells. In a square battery cell, the electrode assembly 10 is a flat structure, the housing 20 is a square hollow structure, and the end cap 30 is a square plate structure.

[0172] In some embodiments, the side wall 22 of the shell 20 extends along the thickness direction Z of the end cover 30 and is arranged around the periphery of the electrode assembly 10. The inner wall surface 221 of the side wall and the outer peripheral surface 321 of the protrusion are both parallel to the thickness direction Z and are arranged opposite to each other.

[0173] The side wall 22 of the shell 20 has an inner wall surface and an outer wall surface arranged opposite to each other, and the inner wall surface 221 of the side wall faces the electrode assembly 10. The inner wall surface 221 of the side wall and the outer wall surface 222 of the side wall are both cylindrical surfaces. The inner wall surface 221 of the side wall is a curved surface formed by the parallel movement of the first busbar along a set trajectory. Optionally, the inner wall surface 221 of the side wall is a cylindrical surface, that is, the inner wall surface 221 of the side wall is a curved surface formed by the parallel movement of the first busbar along a circular trajectory. Optionally, the outer wall surface 222 of the side wall is also a cylindrical surface.

[0174] The outer peripheral surface 321 of the convex portion is a cylindrical surface. The outer peripheral surface 321 of the convex portion is a curved surface formed by the parallel movement of the second generatrix along the set trajectory. Optionally, the outer peripheral surface 321 of the convex portion is a cylindrical surface.

[0175] When the first generatrix is ​​parallel to the second generatrix, the outer peripheral surface 321 of the protrusion is parallel to the inner wall surface 221 of the side wall.

[0176] The inner wall surface 221 of the side wall surrounds the outer peripheral surface 321 of the protrusion, so that after the protrusion 32 extends into the shell 20, the inner wall surface 221 of the side wall can limit the position of the end cover 30 through the outer peripheral surface 321 of the protrusion.

[0177] In this embodiment, the inner wall surface 221 of the side wall and the outer peripheral surface 321 of the protrusion are arranged in parallel. In this way, when the inner wall surface 221 of the side wall and the outer peripheral surface 321 of the protrusion contact and squeeze each other, the force between the two is relatively uniform, thereby reducing stress concentration and reducing deformation of the shell 20 and the protrusion 32.

[0178] In some embodiments, the side wall 22 of the housing 20 and the protrusion 32 are interference-fitted so that the inner wall surface 221 of the side wall and the outer peripheral surface 321 of the protrusion abut against each other.

[0179] The portion of the protrusion 32 extending into the housing 20 may be interference fit with the housing 20 as a whole or partially.

[0180] Taking the example that the outer peripheral surface 321 of the protrusion and the inner wall surface 221 of the side wall are both cylindrical surfaces, before assembling the end cover 30 and the shell 20, the diameter of the outer peripheral surface 321 of the protrusion is larger than the diameter of the inner wall surface 221 of the side wall. In this way, after the protrusion 32 extends into the shell 20, the part of the protrusion 32 extending into the shell 20 has an interference fit with the shell 20.

[0181] In this embodiment, the interference fit can increase the connection strength between the housing 20 and the end cap 30, improving the sealing performance. In this embodiment, the recess 33 is provided to reduce the strength of the protrusion 32, thereby reducing the force between the protrusion 32 and the housing 20 during the process of the protrusion 32 extending into the housing 20. In this way, even if the housing 20 and the protrusion 32 have an interference fit, the generation of particles can be reduced, the risk of deformation of the housing 20 is reduced, and the safety performance of the battery cell 7 is improved.

[0182] In some embodiments, the inner wall surface 221 of the sidewall is welded to the outer peripheral surface 321 of the protrusion to form a first weld W1. In the thickness direction Z, the first weld W1 does not extend beyond the outer surface 312 of the cover body in a direction away from the electrode assembly 10.

[0183] Optionally, the protrusion 32 and the side wall 22 are connected by laser welding. When welding the protrusion 32 and the side wall 22, a laser is irradiated at the junction of the outer peripheral surface 321 of the protrusion and the inner wall surface 221 of the side wall. The laser melts at least a portion of the outer peripheral surface 321 of the protrusion and a portion of the inner wall surface 221 of the side wall, thereby connecting them together.

[0184] In this embodiment, the first welding portion W1 closes the opening 21 to achieve sealing, thereby reducing the risk of electrolyte leakage from between the outer peripheral surface 321 of the protrusion and the inner wall surface 221 of the side wall.

[0185] When welding the protrusion 32 to the housing 20, if the protrusion 32 and the housing 20 form an interference fit, no external equipment is required to secure the end cap 30, thereby simplifying the assembly process. Furthermore, the outer circumferential surface 321 of the protrusion abuts the inner surface 221 of the sidewall, which reduces the risk of laser penetration into the interior of the housing 20 and burning the electrode assembly 10. The interference fit also blocks the gaseous byproducts generated by welding, reducing the amount of gaseous byproducts that pass between the outer circumferential surface 321 of the protrusion and the inner surface 221 of the sidewall, thereby reducing the risk of burns to the separator of the electrode assembly.

[0186] In this embodiment, in the thickness direction Z, the exposed surface of the first welding portion W1 does not exceed the outer surface 312 of the cover body in a direction away from the electrode assembly 10 .

[0187] The cover body 31 serves as a load-bearing structure for the battery cell 7. After the battery cell 7 is installed in the electrical device, the external support structure can support the battery cell 7 through the cover body 31. In this embodiment, the first weld W1 does not extend beyond the outer surface 312 of the cover body in the direction away from the electrode assembly 10. This reduces the force between the external support structure and the first weld W1, lowering the risk of cracking the first weld W1 and ensuring the connection strength and sealing performance between the housing 20 and the end cap 30.

[0188] In some embodiments, the sidewall 22 includes a first outer end surface 223 surrounding the opening 21, and the first outer end surface 223 is connected to the inner wall surface 221 of the sidewall. In the thickness direction Z, the protrusion 32 has a second outer end surface 322 at the end facing away from the electrode assembly 10, and the second outer end surface 322 is connected to the outer peripheral surface 321 of the protrusion. The first outer end surface 223 and the second outer end surface 322 are flush, and the first outer end surface 223 and the second outer end surface 322 are closer to the electrode assembly 10 than the outer surface 312 of the cover body.

[0189] The first outer end surface 223 connects the inner wall surface 221 of the side wall and the outer wall surface 222 of the side wall. The second outer end surface 322 is connected to the side wall surface of the recessed portion 33 at one end thereof that is away from the outer peripheral surface 321 of the protrusion.

[0190] Optionally, the first outer end surface 223 and the second outer end surface 322 are both perpendicular to the inner wall surface 221 of the side wall and the outer peripheral surface 321 of the protrusion.

[0191] The first welding portion W1 formed by welding is uneven and may protrude from the first outer end surface 223 and the second outer end surface 322. If the first outer end surface 223 is flush with the outer surface 312 of the cover body, the first welding portion W1 may serve as the load-bearing part of the battery cell 7, causing the risk of the first welding portion W1 breaking.

[0192] In this embodiment, the first outer end face 223 and the second outer end face 322 are closer to the electrode assembly 10 than the outer surface 312 of the cover body. In this way, even if the first welding portion W1 protrudes from the first outer end face 223 and the second outer end face 322, the first welding portion W1 can be prevented from exceeding the outer surface 312 of the cover body in the direction away from the electrode assembly 10, thereby reducing the force acting on the first welding portion W1, reducing the risk of the first welding portion W1 breaking, and ensuring the connection strength and sealing performance between the shell 20 and the end cover 30.

[0193] In some embodiments, the protrusion 32 also includes a guide surface 323 facing the side wall 22, the guide surface 323 is connected to the end of the outer peripheral surface 321 of the protrusion close to the electrode assembly 10, and the guide surface 323 is inclined in a direction away from the inner wall surface 221 of the side wall compared to the outer peripheral surface 321 of the protrusion to guide the protrusion 32 to extend into the shell 20.

[0194] The guide surface 323 is spaced apart from the inner wall surface 221 of the side wall. In the direction from the end cover 30 to the electrode assembly 10, the radial distance between the guide surface 323 and the inner wall surface 221 of the side wall gradually increases.

[0195] In this embodiment, an inclined guide surface 323 is provided on the protrusion 32, so that the protrusion 32 can be guided to be inserted into the shell 20 when assembling the end cover 30 and the shell 20 (especially when the protrusion 32 and the shell 20 have an interference fit), thereby simplifying the assembly process and improving assembly efficiency.

[0196] Figure 7 Schematic cross-sectional views of battery cells provided in some other embodiments of the present application.

[0197] In some embodiments, the housing 20 further includes a flange portion 24 . The flange portion 24 is connected to the side wall 22 and is bent relative to the side wall 22 toward the cover body 31 to cover the first welding portion W1 .

[0198] The flange portion 24 is integrally formed with the side wall 22 and is formed by a flange process.

[0199] An end of the flange portion 24 facing away from the side wall 22 forms an opening 21 .

[0200] When assembling the end cap 30 and the housing 20, the protrusion 32 of the end cap 30 is inserted into the housing 20, and then the protrusion 32 and the side wall 22 are welded to form a first weld W1. After welding is completed, the portion of the housing 20 near the opening 21 is rolled to form a flange portion 24 covering the first weld W1.

[0201] In this embodiment, the flange portion 24 can protect the first welding portion W1 , reduce the risk of the first welding portion W1 being corroded or damaged, and ensure the connection strength and sealing performance between the shell 20 and the end cover 30 .

[0202] In some embodiments, the surface of the flange portion 24 facing away from the electrode assembly 10 is flush with the outer surface of the cover body.

[0203] Figure 8 A schematic cross-sectional view of a battery cell provided in some other embodiments of the present application; Figure 9 for Figure 8 An enlarged schematic diagram of a battery cell shown at circle B; Figure 10 for Figure 9 Enlarged schematic diagram at box C.

[0204] like Figures 8 to 10 As shown, in some embodiments, the end cover 30 also includes an extension portion 36 that protrudes from the outer peripheral surface 321 of the protrusion and surrounds the outer side of the protrusion 32, and the inner surface 361 of the extension portion is welded to the first outer end surface 223 of the side wall 22 surrounding the opening, so that the shell 20 and the end cover 30 are connected as one.

[0205] The extension portion 36 includes an inner surface and an outer surface disposed opposite to each other along the thickness direction Z. The inner surface 361 of the extension portion faces the electrode assembly 10. Optionally, the extension portion 36 is an annular flat plate structure, and both the inner surface 361 and the outer surface 362 of the extension portion are plane.

[0206] The extension portion 36 and the sidewall 22 are arranged along the thickness direction Z, and the inner surface 361 of the extension portion may be disposed parallel to the first outer end surface 223 .

[0207] Optionally, when welding the extension portion 36 and the side wall 22, the laser is irradiated at the junction of the first outer end surface 223 and the inner surface 361 of the extension portion; after welding, at least part of the inner surface 361 of the extension portion and at least part of the first outer end surface 223 are melted and connected together.

[0208] The inner surface 361 of the extension portion is welded to the first outer end surface 223 of the side wall 22 to form a second welding portion W2 .

[0209] The first outer end surface 223 is located at the outermost end of the housing 20 . In this embodiment, the inner surface 361 of the extension portion abuts against the first outer end surface 223 .

[0210] In this embodiment, when assembling the end cover 30 and the shell 20, the first outer end surface 223 can serve as an upper limit in the thickness direction Z of the end cover 30, reducing the risk of over-insertion of the end cover 30 into the shell 20 and improving assembly efficiency.

[0211] In some embodiments, the protrusion 32 and the housing 20 are clearance-fitted to form a gap between the outer peripheral surface 321 of the protrusion and the inner wall surface 221 of the side wall.

[0212] Taking the example that the outer peripheral surface 321 of the protrusion and the inner wall surface 221 of the side wall are both cylindrical surfaces, before assembling the end cover 30 and the shell 20, the diameter of the outer peripheral surface 321 of the protrusion is smaller than the diameter of the inner wall surface 221 of the side wall. In this way, after the protrusion 32 extends into the shell 20, the part of the protrusion 32 extending into the shell 20 is clearance-fitted with the shell 20.

[0213] In this embodiment, the clearance fit can not only ensure that the shell 20 limits the protrusion 32, but also reduce the force between the protrusion 32 and the shell 20 when the protrusion 32 extends into the shell 20, thereby reducing the risk of friction between the protrusion 32 and the shell 20, reducing the generated particles and reducing the deformation of the shell 20, thereby improving the safety performance of the battery cell 7.

[0214] In some embodiments, in the direction from the electrode assembly 10 to the side wall 22 , the size of the gap between the outer peripheral surface 321 of the protrusion and the inner wall surface 221 of the side wall is 0.02 mm-0.5 mm.

[0215] For example, “a direction from the electrode assembly toward the side wall” may be a radial direction.

[0216] For example, the gap between the outer circumferential surface 321 of the protrusion and the inner surface 221 of the sidewall, as measured from the electrode assembly 10 toward the sidewall 22, is dimensioned L1. The smaller the value of L1, the higher the risk of friction between the outer circumferential surface 321 of the protrusion and the inner surface 221 of the sidewall, and the higher the risk of particle generation. The larger the value of L1, the greater the range of motion of the protrusion 32 after it extends into the housing 20, and the higher the risk of poor welding between the extension 36 and the housing 20. Through experiments, the inventors set the value of L1 to 0.02 mm to 0.5 mm to balance risks and improve safety.

[0217] In some embodiments, the inner surface 361 of the extension portion is provided with an avoidance groove 363 , which surrounds the outer side of the protrusion 32 , and the groove wall of the avoidance groove 363 is used to connect the inner surface 361 of the extension portion and the outer peripheral surface 321 of the protrusion.

[0218] The recess 33 and the protrusion 32 can be formed by a stamping process. The inventors discovered that during the stamping process, stress concentration occurs at the junction of the protrusion and the extension. To reduce this stress concentration, the inventors attempted to provide a rounded corner at the junction of the protrusion and the extension. However, after stamping, the rounded corner is formed at the junction of the inner and outer surfaces of the extension. Since the rounded corner surface is relatively smooth, it may abut against the first outer end surface during the insertion of the protrusion into the housing, preventing the first outer end surface from being in close contact with the inner surface of the extension.

[0219] To address this issue, the inventors designed an escape groove 363 on the extension 36. The portion of the extension 36 opposite the escape groove 363 is connected to the protrusion 32. The recessed design of the escape groove 363 provides space for material flow during the molding of the protrusion 32. Consequently, a rounded corner is formed on the portion of the extension 36 opposite the escape groove 363. The rounded corner's surface forms part of the wall surface of the escape groove 363. The wall surface is recessed relative to the inner surface 361 of the extension. Therefore, this embodiment ensures that the first outer end surface 223 smoothly abuts the inner surface 361 of the extension.

[0220] In some embodiments, the outer surface 362 of the extension is flush with the outer surface 312 of the cover body.

[0221] In this embodiment, the external support structure can support the battery cell 7 through the extension portion 36 and the cover body 31 , which can increase the area of ​​the load-bearing portion of the end cover 30 and improve the stability of the battery cell 7 .

[0222] In some embodiments, in the direction from the electrode assembly 10 to the sidewall 22 , the extension portion 36 does not extend beyond the outer wall surface 222 of the sidewall.

[0223] This embodiment can prevent the extension portion 36 from increasing the maximum size of the battery cell 7, thereby ensuring the energy density of the battery cell 7. In addition, the end cap 30 is relatively thin, and if the extension portion 36 exceeds the outer wall surface 222 of the side wall, it may scratch other external components.

[0224] In some embodiments, in the direction from the electrode assembly 10 to the side wall 22 , the outer wall surface 222 of the side wall extends beyond the extension portion by 0.02 mm to 0.5 mm.

[0225] The second weld portion W2 formed by welding the inner surface 361 of the extension portion to the first outer end surface 223 of the side wall 22 will protrude from the end surface 364 of the extension portion 36. If the outer surface 222 of the side wall were flush with the end surface 364 of the extension portion 36 facing away from the protrusion 32, the second weld portion W2 would likely protrude from the outer surface 222 of the side wall, increasing the maximum size of the battery cell 7 and easily scratching other external components. Therefore, in this embodiment, the outer surface 222 of the side wall is positioned beyond the extension portion 36 to reduce the risk of the second weld portion W2 protruding from the outer surface 222 of the side wall.

[0226] In the direction from electrode assembly 10 toward sidewall 22, the outer wall surface 222 of the sidewall protrudes beyond the extension portion 36 by a dimension L2. The smaller the value of L2, the higher the risk that the second weld portion W2 will protrude beyond the outer wall surface 222 of the sidewall. The larger the value of L2, the smaller the connection area between the extension portion 36 and the sidewall 22, and the lower the connection strength between the extension portion 36 and the sidewall 22.

[0227] After experiments, the inventors set the value of L2 to 0.02 mm-0.5 mm, so as to minimize the risk of the second welding portion W2 protruding from the outer wall surface 222 of the side wall while ensuring the connection strength.

[0228] In some embodiments, in the direction from the electrode assembly 10 to the side wall 22 , a dimension L3 of the outer peripheral surface 321 of the extension portion 36 protruding from the convex portion is smaller than the wall thickness of the side wall 22 .

[0229] Exemplarily, L3 is the distance in the radial direction between the end surface 364 of the extension portion 36 and the outer peripheral surface 321 of the protrusion.

[0230] In this embodiment, when the outer peripheral surface 321 of the protrusion abuts against the inner wall surface 221 of the side wall, since the wall thickness of the side wall 22 is greater than the size of the outer peripheral surface 321 of the protrusion protruding from the extension portion 36, the outer wall surface 222 of the side wall exceeds the extension portion 36 in the direction of the electrode assembly 10 pointing to the side wall 22.

[0231] Figure 11 A schematic flow chart of a method for manufacturing a battery cell provided in some embodiments of the present application.

[0232] like Figure 11 As shown, the manufacturing method of the battery cell of the embodiment of the present application includes:

[0233] S100, providing a housing, wherein the housing has an opening;

[0234] S200, providing an electrode assembly and installing the electrode assembly into a housing;

[0235] S300, providing an end cap, the end cap comprising a cap body and a convex portion surrounding the outer side of the cap body, the convex portion protruding from the inner surface of the cap body, a concave portion formed on the end cap at a position corresponding to the convex portion, the concave portion being recessed from the outer surface of the cap body;

[0236] S400, extending at least a portion of the protrusion into the housing to engage with the housing;

[0237] S500, connecting the end cover and the housing so that the end cover covers the opening;

[0238] The convex portion protrudes from the inner surface of the cover body in the direction facing the electrode assembly, the concave portion is recessed from the outer surface of the cover body in the direction facing the electrode assembly, and the concave portion is used to release stress when the convex portion extends into the shell.

[0239] It should be noted that the relevant structure of the battery cell manufactured by the above-mentioned method for manufacturing the battery cell can refer to the battery cells provided in the above-mentioned embodiments.

[0240] When assembling a battery cell based on the above-mentioned battery cell manufacturing method, it is not necessary to follow the above-mentioned steps in sequence. In other words, the steps can be performed in the order mentioned in the embodiment, or in a different order than the order mentioned in the embodiment, or several steps can be performed simultaneously. For example, steps S100 and S300 can be performed in any order and can be performed simultaneously.

[0241] Figure 12 A schematic block diagram of a battery cell manufacturing system provided in some embodiments of the present application.

[0242] like Figure 12 As shown, the battery cell manufacturing system 90 of the embodiment of the present application includes:

[0243] A first providing device 91 is used to provide a housing having an opening;

[0244] A second providing device 92 is used to provide an electrode assembly and install the electrode assembly into the housing;

[0245] A third providing device 93 is used to provide an end cap, the end cap comprising a cap body and a convex portion surrounding the outer side of the cap body, the convex portion protruding from the inner surface of the cap body, and a concave portion formed on the end cap at a position corresponding to the convex portion, the concave portion being recessed from the outer surface of the cap body;

[0246] a first assembly device 94 for extending at least a portion of the protrusion into the housing and for mating with the housing;

[0247] A second assembly device 95 connects the end cap and the housing so that the end cap covers the opening;

[0248] The convex portion protrudes from the inner surface of the cover body in the direction facing the electrode assembly, the concave portion is recessed from the outer surface of the cover body in the direction facing the electrode assembly, and the concave portion is used to release stress when the convex portion extends into the shell.

[0249] The relevant structures of the battery cells manufactured by the above manufacturing system can refer to the battery cells provided in the above embodiments.

[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 of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery cell, comprising: a housing having an opening; an electrode assembly housed in the housing, comprising a first electrode sheet, a second electrode sheet, and a separator, wherein the first electrode sheet, the second electrode sheet, and the separator are wound together to form a wound structure; as well as an end cap, configured to cover the opening, the end cap comprising a cap body and a protrusion surrounding the outside of the cap body, the protrusion protruding from the inner surface of the cap body in a direction facing the electrode assembly, and at least a portion of the protrusion being located within the housing and configured to cooperate with the housing; A recess is formed on the end cap at a position corresponding to the convex portion, the recess being recessed from the outer surface of the cap body in a direction facing the electrode assembly and being used to release stress when the convex portion extends into the shell; The protrusion abuts against the first tab of the electrode assembly to support the first tab.

2. The battery cell according to claim 1, wherein: In the thickness direction of the end cover, the bottom surface of the recess is closer to the electrode assembly than the inner surface of the cover body as a whole.

3. The battery cell according to claim 1 or 2, wherein: The side wall of the shell extends along the thickness direction of the end cover and is arranged around the periphery of the electrode assembly. The inner wall surface of the side wall and the outer peripheral surface of the protrusion are both parallel to the thickness direction and are arranged opposite to each other.

4. The battery cell according to claim 3, wherein: The side wall of the housing and the convex portion are interference-fitted so that the inner wall surface of the side wall and the outer peripheral surface of the convex portion abut against each other.

5. The battery cell according to claim 3, wherein: The inner wall surface of the side wall is welded to the outer peripheral surface of the protrusion to form a first welding portion; In the thickness direction, the first welding portion does not extend beyond the outer surface of the cover body in a direction away from the electrode assembly. The battery cell according to claim 5 , wherein: The side wall includes a first outer end surface surrounding the opening, and the first outer end surface is connected to the inner wall surface of the side wall; In the thickness direction, the protrusion has a second outer end surface at the end away from the electrode assembly, the second outer end surface is connected to the outer peripheral surface of the protrusion, the first outer end surface and the second outer end surface are flush, and the first outer end surface and the second outer end surface are closer to the electrode assembly than the outer surface of the cover body.

7. The battery cell according to claim 5, wherein: The shell further includes a flange portion connected to the side wall and bent relative to the side wall toward the cover body to cover the first welding portion.

8. The battery cell according to claim 3, wherein: The end cover also includes an extension portion protruding from the outer peripheral surface of the protrusion and surrounding the outer side of the protrusion, and the inner surface of the extension portion is welded to the first outer end surface of the side wall surrounding the opening, so that the shell and the end cover are connected as one.

9. The battery cell according to claim 8, wherein: The convex portion and the housing are clearance-matched to form a gap between the outer peripheral surface of the convex portion and the inner wall surface of the side wall.

10. The battery cell according to claim 9, wherein: In the direction from the electrode assembly to the side wall, the size of the gap between the outer peripheral surface of the protrusion and the inner wall surface of the side wall is 0.02 mm-0.5 mm.

11. The battery cell according to any one of claims 8 to 10, wherein: An escape groove is provided on the inner surface of the extension portion, and the escape groove surrounds the outer side of the convex portion. The groove wall surface of the escape groove is used to connect the inner surface of the extension portion and the outer peripheral surface of the convex portion.

12. The battery cell according to any one of claims 8 to 10, wherein: An outer surface of the extension portion is flush with an outer surface of the cover body.

13. The battery cell according to any one of claims 8 to 10, wherein: In a direction from the electrode assembly to the side wall, the extension portion does not exceed the outer wall surface of the side wall.

14. The battery cell according to claim 13, wherein: In the direction from the electrode assembly to the side wall, the outer wall surface of the side wall exceeds the extension portion by 0.02 mm to 0.5 mm.

15. The battery cell according to claim 13, wherein: In a direction from the electrode assembly to the side wall, a dimension of the extension portion protruding from the outer circumference of the convex portion is smaller than a wall thickness of the side wall.

16. The battery cell according to claim 3, wherein: The protrusion also includes a guide surface facing the side wall, the guide surface is connected to the end of the outer peripheral surface of the protrusion close to the electrode assembly, and the guide surface is inclined in a direction away from the inner wall surface of the side wall compared to the outer peripheral surface of the protrusion to guide the protrusion to extend into the shell.

17. The battery cell according to claim 1, wherein The protrusion is welded to the first electrode tab to electrically connect the first electrode tab and the end cover.

18. The battery cell according to claim 1, wherein The first tab of the electrode assembly is electrically connected to the shell through the end cover.

19. The battery cell according to claim 18, wherein: The housing includes a side wall and a bottom wall, wherein the side wall extends along the thickness direction of the end cap and surrounds the periphery of the electrode assembly, and the bottom wall is connected to one end of the side wall and is located on a side of the electrode assembly away from the end cap, and the bottom wall is provided with an electrode lead-out hole; The electrode assembly is provided with a second electrode tab at one end facing the bottom wall, and the first electrode tab and the second electrode tab have opposite polarities; The battery cell further includes an electrode terminal installed in the electrode lead-out hole, and the electrode terminal is electrically connected to the second electrode tab.

20. The battery cell according to claim 19, wherein The bottom wall and the side wall are integrally formed.

21. The battery cell according to any one of claims 18 to 20, wherein: The first electrode tab is a negative electrode tab, and the base material of the shell is steel.

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

23. A battery comprising a plurality of battery cells according to any one of claims 1 to 22.

24. An electrical device comprising the battery according to claim 23, wherein the battery is used to provide electrical energy.

25. A method for manufacturing a battery cell, comprising: providing a housing having an opening; Providing an electrode assembly, and installing the electrode assembly into the housing; Providing an end cap, the end cap comprising a cap body and a convex portion surrounding the outer side of the cap body, the convex portion protruding from the inner surface of the cap body, a concave portion formed on the end cap at a position corresponding to the convex portion, the concave portion being recessed from the outer surface of the cap body; Extending at least a portion of the protrusion into the housing and adapted to engage with the housing; Connecting the end cover and the housing so that the end cover covers the opening; The convex portion protrudes from the inner surface of the cover body in the direction facing the electrode assembly, and the concave portion is recessed from the outer surface of the cover body in the direction facing the electrode assembly, and the concave portion is used to release stress during the process of the convex portion extending into the shell, and the convex portion abuts against the first pole ear of the electrode assembly to support the first pole ear.

26. A battery cell manufacturing system comprising: A first providing device is used to provide a housing, wherein the housing has an opening; a second providing device, configured to provide an electrode assembly and install the electrode assembly into the housing; A third providing device is configured to provide an end cap, the end cap comprising a cap body and a convex portion surrounding an outer side of the cap body, the convex portion protruding from an inner surface of the cap body, a concave portion formed on the end cap at a position corresponding to the convex portion, the concave portion being recessed from the outer surface of the cap body; a first assembly device for extending at least a portion of the protrusion into the housing and for mating with the housing; a second assembling device, connecting the end cover and the housing so that the end cover covers the opening; The convex portion protrudes from the inner surface of the cover body in the direction facing the electrode assembly, and the concave portion is recessed from the outer surface of the cover body in the direction facing the electrode assembly, and the concave portion is used to release stress during the process of the convex portion extending into the shell, and the convex portion abuts against the first pole ear of the electrode assembly to support the first pole ear.

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