Battery cell and manufacturing method therefor, battery device, and electric device

Abstract

The present application discloses a battery cell and a manufacturing method therefor, a battery device, and an electric device. The battery cell comprises a casing and an electrode assembly. The casing comprises a casing body and an end wall, the end wall comprises a wall body and a connecting portion, at least part of the connecting portion is annularly arranged on the periphery of the wall body, a step portion is formed on the inner side of the end wall, the step portion abuts against the casing body, the connecting portion is connected to the casing body so as to close an opening, and the tensile strength of the step portion under the condition of a temperature of 25°C is Rm, wherein 250 MPa≤Rm≤2000 MPa. In the thickness direction of the end wall, the wall body has a first surface facing away from the electrode assembly, and the distance between the side of the connecting portion facing away from the electrode assembly and the first surface is less than or equal to 0.5 mm. The technical solution provided in the present application can effectively improve the reliability of the battery device.

Description

Battery cells and their manufacturing methods, battery devices and electrical devices Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to a battery cell and its manufacturing method, a battery device, and an electrical device. Background Technology

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry, and electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of this sustainable development. For electric vehicles, battery technology is a crucial factor in their development.

[0003] In the development of battery technology, how to improve the reliability of battery devices is a technical problem that urgently needs to be solved. Summary of the Invention

[0004] This application provides a battery cell and its manufacturing method, a battery device, and an electrical device. The technical solution provided by this application can effectively improve the reliability of the battery device.

[0005] This application is achieved through the following technical solution:

[0006] In a first aspect, some embodiments of this application provide a battery cell, which includes a housing and an electrode assembly. The electrode assembly is disposed within the housing. The housing includes a shell and an end wall, the shell having an opening. The end wall includes a wall body and a connecting portion, at least a portion of which is circumferentially disposed around the outer periphery of the wall body. A stepped portion is formed on the inner side of the end wall, the stepped portion abutting against the shell. The connecting portion is connected to the shell to close the opening. The tensile strength Rm of the stepped portion at a temperature of 25°C satisfies 250MPa≤Rm≤2000MPa. Along the thickness direction of the end wall, the wall body has a first surface facing away from the electrode assembly, and the distance between the side of the connecting portion facing away from the electrode assembly and the first surface is less than or equal to 0.5mm.

[0007] In the above solution, on the one hand, by limiting the range of the room temperature tensile strength Rm of the stepped portion, and ensuring that this range satisfies 250MPa≤Rm≤2000MPa, the deformation resistance of this part is high, thus resisting the expansion of the electrode assembly and making the joint between the end wall and the shell less prone to damage, thereby improving the reliability of the battery cell. On the other hand, by processing the portion located on the outer periphery of the wall body, the distance difference between the side of the connection part away from the electrode assembly and the first surface of the wall body is no more than 0.5mm. At the battery device level, this effectively improves the problem of end wall structure damage caused by external structural extrusion, or damage to structural components located on the outer side of the end wall, such as insulation failure caused by extrusion of the insulation component located on the outer side of the end wall, thereby effectively improving the reliability of the battery device. In particular, in battery cells where the end wall and the shell are welded together, the stepped design of the end wall, through machining and other processes, thins the protrusion on the outer side of the end wall to form the connection part, which facilitates the connection of the insulation component and reduces the risk of damage to the insulation component structure caused by external structural extrusion, thereby improving the reliability of the battery device.

[0008] According to some embodiments of this application, along the thickness direction of the end wall, the distance between the side of the connection portion away from the electrode assembly and the first surface is less than or equal to 0.3 mm.

[0009] In the above solution, by processing the connecting part located on the outer periphery of the wall body, the distance difference between the side of the connecting part away from the electrode assembly and the first surface of the wall body is no more than 0.3mm. This can further and effectively improve the problem of insulation failure caused by structural damage to the end wall and the insulating parts located on the outer side of the end wall due to extrusion, thereby effectively improving the reliability of the battery device.

[0010] According to some embodiments of this application, the side of the connecting portion away from the electrode assembly includes a second surface, which protrudes from the first surface along the direction of the electrode assembly toward the end wall.

[0011] In the above scheme, along the direction of the electrode assembly pointing towards the end wall, the second surface of the connection protrudes beyond the first surface, and the size of the second surface protruding beyond the first surface is no greater than 0.5 mm. This effectively reduces the risk of insulation failure caused by local puncture due to external structural compression of the end wall and the insulating component located outside the end wall, thus effectively improving the reliability of the battery device. Particularly in battery cells where the end wall is welded to the casing, the end wall features a stepped design. Through machining and other processes, the protrusion on the outer side of the end wall is thinned to form the second surface, and the size of the second surface protruding beyond the first surface is no greater than 0.5 mm. This reduces the risk of structural damage to the insulating component due to external structural compression, thereby further improving the reliability of the battery device.

[0012] According to some embodiments of this application, the side of the connecting portion away from the electrode assembly includes a third surface, and the first surface protrudes from the third surface along the direction of the electrode assembly toward the end wall.

[0013] In the above-described design, the outer side of the connecting portion has a third surface recessed relative to the first surface, and the size of the recess is no greater than 0.5 mm. This effectively reduces the risk of insulation failure caused by local punctures due to external structural compression of the end wall and the insulating components located on the outer side of the end wall, thus significantly improving the reliability of the battery device. Particularly in battery cells where the end wall is welded to the casing, the end wall features a stepped design. Through machining and other processes, the steps are thinned to form a third surface recessed relative to the first surface, with the size of the third surface recess no greater than 0.5 mm. This reduces the risk of structural damage to the insulating components due to external structural compression, further enhancing the reliability of the battery device.

[0014] According to some embodiments of this application, the side of the connection portion away from the electrode assembly includes a fourth surface, which is flush with the first surface.

[0015] In the above-described design, the outer side of the connecting portion has a fourth surface flush with the first surface. The insulating component is connected to the fourth surface, which effectively reduces the risk of insulation failure caused by local punctures due to external structural pressure on the end wall and the insulating component located on the outer side of the end wall. This effectively improves the reliability of the battery device. Particularly in battery cells where the end wall is welded to the casing, the end wall features a stepped design. Through machining and other processes, the protrusions on the outer side of the end wall are thinned to form a fourth surface flush with the first surface. This reduces the risk of structural damage to the insulating component due to external structural pressure, further enhancing the reliability of the battery device.

[0016] According to some embodiments of this application, the connecting portion on the side opposite to the electrode assembly includes a second surface and a third surface, the second surface and the third surface are connected, and along the direction of the electrode assembly pointing to the end wall, the second surface protrudes from the first surface, and the first surface protrudes from the third surface.

[0017] In the above scheme, the outer side of the connecting part includes a second surface and a third surface. The second surface protrudes relative to the first surface, and the protrusion size is no greater than 0.5 mm. The third surface is recessed relative to the first surface, and the recess size is no greater than 0.5 mm. On the one hand, this makes the outer side of the connecting part relatively flat with the outer side of the wall body, which can effectively reduce the risk of insulation failure caused by local puncture due to external structure compression of the end wall and the insulating parts located on the outer side of the end wall, and can effectively improve the reliability of the battery device. On the other hand, the concave and convex shape of the outer periphery of the end wall can effectively improve the structural strength of the end wall, which is conducive to improving the structural strength of the battery cell and the reliability of the battery device.

[0018] According to some embodiments of this application, the connecting part is an annular structure, the inner periphery of the connecting part is connected to the wall body, and the distance between the connecting part and the electrode assembly on the side away from the electrode assembly in the thickness direction of the end wall gradually decreases along the direction from the inner periphery of the connecting part to the outer periphery of the connecting part.

[0019] In the above scheme, along the direction from the inner periphery of the connector to the outer periphery, the distance between the side of the connector away from the electrode assembly and the electrode assembly in the thickness direction of the end wall gradually decreases. This causes the outer side of the connector to be inclined, enabling a smooth transition of the insulating component at the junction of the shell and the end wall. This reduces the risk of stress concentration and structural damage to the insulating component, resulting in high reliability of the battery cell and improving the reliability of the battery device. Particularly in battery cells where the end wall is welded to the shell, the end wall features a stepped design. Through machining and other processes, the protrusion on the outer side of the end wall is thinned at a certain angle, causing the outer side of the connector to be inclined. This reduces the risk of local structural damage to the insulating component, thereby improving the reliability of the battery cell.

[0020] According to some embodiments of this application, the hardness of the connecting portion is greater than the hardness of the wall body.

[0021] In the above scheme, by setting the hardness of the connecting part to be greater than that of the wall body, the connection quality between the shell and the end wall can be improved, reducing the risk of separation of the end wall and the shell due to impact, thus improving the reliability of the battery cell and the battery device. Particularly in battery cells where the end wall and shell are welded together, the end wall features a stepped design. By thinning the protrusions on the outer side of the end wall through machining and other processes, the risk of insulation failure due to localized punctures caused by external structural pressure can be reduced. Furthermore, it can increase the hardness of the local structure of the end wall, resulting in a high-quality connection between the shell and the end wall, which is beneficial to improving the reliability of the battery device.

[0022] According to some embodiments of this application, the connecting portion is connected to the housing via a first joint portion, and the stepped portion includes a first stepped surface and a second stepped surface that are connected to each other. The first stepped surface is formed on the side of the connecting portion facing the electrode assembly along the radial direction of the end wall, and the second stepped surface is formed on the side of the wall body facing the inner wall surface of the housing along the thickness direction of the end wall. The housing has a first end face facing the connecting portion, and the first joint portion is located between the first end face and the first stepped surface.

[0023] In the above solution, the connecting part is connected to the shell through the first joint, and the first joint can be disposed on the side of the shell between the first end face and the second step surface, which can reduce the difficulty of connecting the connecting part and the shell, making the manufacturing efficiency of the battery cell high and improving the manufacturing efficiency of the battery device.

[0024] According to some embodiments of this application, the first joint is a solder mark formed between the connecting part and the housing.

[0025] In the above scheme, the connecting part and the shell are connected to each other by welding, and the welding direction can be the side of the battery cell. Therefore, the connection between the connecting part and the shell is reliable, and the connection between the connecting part and the shell is easy and efficient.

[0026] According to some embodiments of this application, the second stepped surface abuts against the inner wall surface of the housing.

[0027] In the above scheme, the second step surface is in contact with the inner wall of the shell, which can play a role in positioning the end wall and the shell, resulting in high assembly accuracy of the end wall and the shell, reducing the difficulty of connecting the connection part and the shell, resulting in high manufacturing efficiency of the battery cell, and thus high manufacturing efficiency of the battery device.

[0028] According to some embodiments of this application, the battery cell further includes an insulating member that covers at least a portion of the outer peripheral surface of the housing, and the insulating member is connected to the connecting portion on the side opposite to the electrode assembly.

[0029] According to some embodiments of this application, a portion of the insulating element is connected to the first surface.

[0030] In the above solution, by connecting part of the insulating component to the first surface, the connection area between the end wall and the insulating component can be increased, thereby improving the reliability of the connection quality between the insulating component and the outer shell, which in turn improves the reliability of the external insulation of the battery cell and the overall reliability of the battery cell.

[0031] According to some embodiments of this application, a portion of the insulating element is connected to the first surface. The battery cell also includes electrode terminals disposed on the first surface and electrically connected to the electrode assembly.

[0032] According to some embodiments of this application, there are two end walls, which are opposite each other and connected to the housing respectively along the thickness direction of the end walls.

[0033] In the above scheme, there are two end walls, which are opposite to each other. This can effectively improve the problem of local damage to the insulation components at both ends of the shell due to interference from external structures, resulting in high insulation reliability of the battery cells and thus improving the reliability of the battery device.

[0034] According to some embodiments of this application, the following condition is met: 450MPa≤Rm≤800MPa.

[0035] On the one hand, limiting the tensile strength Rm of the stepped portion under normal temperature conditions to no less than 450MPa ensures strong deformation capacity of the end wall 111, resisting the expansion of the electrode assembly and making this part less prone to damage. This, in turn, makes the joint between the end wall 111 and the shell 110 less susceptible to damage, reducing the risk of shell 11 cracking and thus improving the structural stability and service life of the battery cell. On the other hand, controlling the tensile strength Rm of the end wall 111 under normal temperature conditions to prevent it from being too high reduces the difficulty of material selection and processing for the end wall 111, saving costs and facilitating processing.

[0036] According to some embodiments of this application, the material of the step portion includes one of the following materials: steel, copper alloy, titanium alloy, and nickel alloy.

[0037] In the above scheme, the material of the step portion includes one of steel, copper alloy, titanium alloy and nickel alloy, so that the end wall has greater strength, can meet the strength requirements of the battery cell shell, and is easy to process and has a lower cost.

[0038] According to some embodiments of this application, the material of the step portion includes stainless steel or carbon steel.

[0039] In the above schemes, if the step is made of stainless steel, its structural strength is high, which can usually meet the tensile strength Rm requirement under normal temperature conditions. Furthermore, stainless steel is less prone to rusting, which, compared to other materials, improves the reliability of the joint between the end wall and the shell, reducing the risk of shell cracking. If the step is made of carbon steel, its structural strength is high, making it easy to meet the tensile strength Rm requirement under normal temperature conditions.

[0040] According to some embodiments of this application, the material of the housing is the same as the material of the stepped portion.

[0041] In the above scheme, the material of the shell is the same as that of the stepped section. That is, the shell, like the end wall, can meet the tensile strength Rm requirement under the above-mentioned room temperature conditions, which can improve the reliability of the joint between the end wall and the shell and reduce the risk of shell cracking. At the same time, the material of the end wall is the same as that of the shell, which can reduce the difficulty of connecting the end wall and the shell. For example, the difficulty of welding the two together is low, which is conducive to improving the manufacturing efficiency of battery cells.

[0042] Secondly, some embodiments of this application also provide a battery device, which includes the battery cell provided in the first aspect.

[0043] Thirdly, some embodiments of this application also provide an electrical device, which includes the battery cell provided in the first aspect and / or the battery device provided in the second aspect.

[0044] Fourthly, some embodiments of this application also provide a method for manufacturing a single battery cell, comprising the following steps:

[0045] A housing is provided, the housing including a shell and an end wall, at least a portion of the end wall being formed by machining, the end wall including a wall body and a connecting portion at least partially circumferentially disposed around the wall body, and a stepped portion formed on the inner side of the end wall, the stepped portion having a tensile strength Rm at a temperature of 25°C, satisfying 250MPa≤Rm≤2000MPa, the outer side of the wall body having a first surface along the thickness direction of the end wall, and the distance between the outer side of the connecting portion and the first surface being less than or equal to 0.5mm;

[0046] The electrode assembly is housed inside the casing;

[0047] The stepped portion abuts against the shell, and the connecting portion is connected to the shell to close the opening of the shell.

[0048] According to some embodiments of this application, the step of providing the housing includes:

[0049] The wall body, stepped portion, and protrusions provided on the outer periphery of the wall body are formed by stamping.

[0050] The protrusion is machined on the side of the end wall opposite to the electrode assembly to form a connection.

[0051] According to some embodiments of this application, the step of providing the housing includes:

[0052] On the side of the end wall facing the electrode assembly, a connection and a step are formed by machining.

[0053] According to some embodiments of this application, the method further includes covering at least a portion of the outer periphery of the housing with an insulating element, and connecting the insulating element to the side of the connection portion opposite to the electrode assembly.

[0054] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0055] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0056] Figure 1 is a schematic diagram of the vehicle structure in some embodiments of this application;

[0057] Figure 2 is an exploded perspective view of the battery device in some embodiments of this application;

[0058] Figure 3 is an exploded perspective view of a battery cell in some embodiments of this application;

[0059] Figure 4 is a schematic diagram of the outer casing in some embodiments of this application;

[0060] Figure 5 is an enlarged view of point A in Figure 4;

[0061] Figure 6 is a schematic diagram of the internal structure of a single battery cell in some embodiments of this application;

[0062] Figure 7 is an enlarged view of point B in Figure 6;

[0063] Figure 8 is a partial structural diagram of the end wall and the shell in some embodiments of this application;

[0064] Figure 9 is an enlarged view of point C in Figure 6;

[0065] Figure 10 is a partial structural diagram of the end wall and the shell in some embodiments of this application;

[0066] Figure 11 is a schematic diagram of the wall body and the connecting part in some other embodiments of this application;

[0067] Figure 12 is a flowchart of a method for manufacturing a single battery cell in some embodiments of this application.

[0068] Icons: 1000 - Vehicle; 100 - Battery unit; 200 - Controller; 300 - Motor; 20 - Housing; 21 - First housing body; 22 - Second housing body; 10 - Battery cell; 11 - Housing; 110 - Shell; 111 - End wall; 112 - Wall body; 1120 - First surface; 1121 - Second stepped surface; 1122 - Terminal hole; 1123 - Injection hole; 113 - Connecting part; 114 - Stepped part; 1130 - Second surface; 1131 - Third surface; 1132 - First stepped surface; 12 - Electrode assembly; 120 - Tab; 13 - Insulator; 14 - Electrode terminal; 15 - Pressure relief mechanism; 16 - Sealing part; 17 - First joint; 18 - Adapter; z - Thickness direction of end wall; 2000 - Manufacturing method of battery cell. Detailed Implementation

[0069] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0070] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0071] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0072] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0073] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0074] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0075] In this application, "multiple" means two or more (including two).

[0076] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0077] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0078] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0079] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0080] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0081] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0082] In some embodiments, the separator is a separator membrane. The separator membrane can be of various types, and any known porous separator membrane with good chemical and mechanical stability can be selected.

[0083] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like, or solid. Liquid electrolytes include electrolyte salts and solvents.

[0084] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0085] In some implementations, the electrode assembly is a stacked structure.

[0086] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0087] As an example, multiple positive electrode plates can be provided, and negative electrode plates can be folded to form multiple stacked folded segments, with a positive electrode plate sandwiched between adjacent folded segments.

[0088] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0089] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0090] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0091] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0092] In some embodiments, the electrode assembly has tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0093] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), or composite metal (such as a copper-aluminum composite housing).

[0094] As an example, a battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include, but are not limited to, square battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries.

[0095] The battery apparatus mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells connected in series, parallel, or mixed connections via a busbar.

[0096] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form a single module. As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0097] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0098] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0099] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0100] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0101] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0102] As an example, the housing can be part of the vehicle's chassis structure. For instance, the housing's roof can be at least part of the vehicle's floor, or the housing's frame can be at least part of the vehicle's crossbeams and longitudinal beams.

[0103] In some embodiments, the battery device may refer to an energy storage device, which includes a housing with a door on at least one side. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0104] As an example, the battery device includes a beam assembly and a battery cell assembly. The beam assembly may include mounting beams and suspension beams arranged in a mutually arranged manner. The suspension beams are used to mount and fix the battery cell assembly, and the mounting beams are used to mount the battery to the power-consuming device body so that the battery supplies power to the power-consuming device body. In some embodiments, the beam assembly may be a partial structural component of the housing.

[0105] Battery devices possess outstanding advantages such as high energy density, low environmental pollution, high power density, long service life, wide applicability, and low self-discharge coefficient, making them an important component of today's new energy development. The development of battery technology must simultaneously consider multiple design factors, such as performance parameters like energy density, cycle life, and discharge capacity. Furthermore, the reliability of the battery device must also be taken into account.

[0106] Generally, a battery cell includes a casing and an electrode assembly, with the electrode assembly housed within the casing. The casing includes an end wall and a housing, with the end wall connected to the housing and sealing the opening of the housing, thus placing the electrode assembly within a closed space. In related technologies, the end wall is stamped to form a step on its outer periphery, causing the step to abut against the end of the housing for positioning and connection. However, stamping the end wall results in a protrusion on its outer side. At the battery assembly level, pressure from other structural components (such as end plates, structural beams, or adjacent battery cells) can damage the end wall and the corresponding structure, for example, puncturing the insulation at the end, thus affecting the reliability of the battery cell and consequently the reliability of the battery assembly.

[0107] Based on the above considerations, at the battery device level, to mitigate the problem of end-wall structure damage caused by compression from other structural components, thus affecting battery device reliability, some embodiments of this application provide a battery cell. The battery cell includes a housing and an electrode assembly. The housing includes a shell and an end wall, the shell having an opening. The end wall includes a wall body and a connecting portion, at least a portion of which is circumferentially disposed around the outer periphery of the wall body. A stepped portion is formed on the inner side of the end wall, abutting against the shell. The connecting portion is connected to the shell to close the opening. The tensile strength Rm of the stepped portion at 25°C satisfies 250MPa≤Rm≤2000MPa. The electrode assembly is disposed within the housing. Along the thickness direction of the end wall, the wall body has a first surface facing away from the electrode assembly, and the distance between the side of the connecting portion facing away from the electrode assembly and the first surface is less than or equal to 0.5mm.

[0108] In the above scheme, on the one hand, by limiting the range of the room temperature tensile strength Rm of the stepped portion, and ensuring that this range satisfies 250MPa≤Rm≤2000MPa, the deformation resistance of this part is high, which can resist the expansion of the electrode assembly and make the joint between the end wall and the shell less prone to damage, thereby improving the reliability of the battery cell. On the other hand, by processing the part located on the outer periphery of the wall body, the distance difference between the side of the connection part away from the electrode assembly and the first surface of the wall body is no more than 0.5mm, which can effectively improve the problem of insulation failure caused by structural damage to the insulation component located on the outer side of the end due to compression, thereby effectively improving the reliability of the battery device. In particular, in battery cells where the end wall and the shell are welded together, the end wall has a stepped design. Through machining and other processes, the protrusion on the outer side of the end wall is thinned to form the connection part, which facilitates the connection of the insulation component and reduces the risk of structural damage to the insulation component caused by external structural compression, thereby improving the reliability of the battery device.

[0109] The battery cells disclosed in this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft.

[0110] This application provides an electrical device that uses a single battery cell or battery assembly as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0111] For ease of explanation, the following embodiments will be described using a vehicle as an example of an electrical device according to an embodiment of this application.

[0112] Please refer to Figure 1, which is a structural schematic diagram of a vehicle 1000 in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 100 is installed inside the vehicle 1000. The battery device 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, it can serve as the vehicle's operating power source or general power source. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 controls the battery device 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during startup, navigation, and driving.

[0113] In some embodiments of this application, the battery device 100 can not only serve as the operating power or power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0114] Please refer to Figure 2, which is an exploded perspective view of the battery device 100 in some embodiments of this application. The battery device 100 includes a housing 20 and battery cells 10, the battery cells 10 being housed within the housing 20.

[0115] The housing 20 provides assembly space for the battery cell 10, and can adopt various structures. In some embodiments, the housing 20 may include a first housing body 21 and a second housing body 22, which overlap each other, and together define an assembly space for accommodating the battery cell 10. The second housing body 22 may be a hollow structure open at one end, and the first housing body 21 may be a plate-like structure, with the first housing body 21 covering the open side of the second housing body 22 so that the first housing body 21 and the second housing body 22 together define the assembly space; alternatively, the first housing body 21 and the second housing body 22 may both be hollow structures open on one side, with the open side of the first housing body 21 covering the open side of the second housing body 22.

[0116] Of course, the box 20 formed by the first box body 21 and the second box body 22 can be of various shapes, such as a cylinder, a cuboid, or a cube. For example, in Figure 2, the shape of the box 20 is a cuboid.

[0117] In the battery device 100, there can be one or more battery cells 10 disposed within the housing 20. When there are multiple battery cells 10 disposed within the housing 20, they can be connected in series, in parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 10 are connected in both series and parallel configurations. Multiple battery cells 10 can be directly connected in series, in parallel, or in a mixed configuration, and then the entire assembly of the multiple battery cells 10 is housed within the housing 20. Alternatively, the battery device 100 can also be composed of multiple battery cells 10 first connected in series, in parallel, or in a mixed configuration to form a battery module, and then the multiple battery modules are connected in series, in parallel, or in a mixed configuration to form a whole, which is then housed within the housing 20.

[0118] In some embodiments, the battery device 100 may also include other structures. For example, the battery device 100 may also include a busbar for connecting multiple battery cells 10 to achieve electrical connection between the multiple battery cells 10.

[0119] For example, the housing 20 is provided with a plurality of battery cell assemblies, each battery cell assembly including a plurality of battery cells 10 stacked on top of each other, and the plurality of battery cells 10 are connected in series with each other through a busbar. In some embodiments, the plurality of battery cell assemblies can be connected in series with each other through a busbar.

[0120] Each battery cell 10 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. The battery cell 10 can be in the form of a cuboid, cylinder, prism, or other shapes. For example, in Figure 3, the battery cell 10 has a cuboid structure.

[0121] Some embodiments of this application provide a battery cell 10. Please refer to Figures 3-5. Figure 3 is an exploded perspective view of the battery cell 10 in some embodiments of this application. Figure 4 is a structural schematic diagram of the outer casing 11 in some embodiments of this application. Figure 5 is an enlarged view of point A in Figure 4.

[0122] The battery cell 10 includes a housing 11 and an electrode assembly 12. The electrode assembly 12 is disposed within the housing 11. The housing 11 includes a shell 110 and an end wall 111. The shell 110 has an opening. The end wall 111 includes a wall body 112 and a connecting portion 113. At least a portion of the connecting portion 113 is arranged around the outer periphery of the wall body 112. A stepped portion 114 is formed on the inner side of the end wall 111. The stepped portion 114 abuts against the shell 110. The connecting portion 113 is connected to the shell 110 to close the opening. The tensile strength Rm of the stepped portion 114 at a temperature of 25°C satisfies 250MPa≤Rm≤2000MPa. Along the thickness direction z of the end wall, the wall body 112 has a first surface 1120 facing away from the electrode assembly 12. The distance between the side of the connecting portion 113 facing away from the electrode assembly 12 and the first surface 1120 is less than or equal to 0.5mm.

[0123] In some embodiments, the outer casing 11 can also be used to contain an electrolyte, such as an electrolyte solution. The outer casing 11 can have various structural forms, such as a square shell structure, a cylindrical shell structure, or a bag-like structure. The outer casing 11 can also be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc.

[0124] In some embodiments, referring to Figures 3 and 4, the housing 11 includes a housing 110 and an end wall 111. The housing 110 has an internal cavity with an opening, meaning the housing 110 is a hollow structure with one open end. The end wall 111 covers the opening of the housing 110 and forms a sealed connection to create a sealed space for accommodating the electrode assembly 12 and the electrolyte. In some embodiments, the connection between the end wall 111 and the housing 110 is varied, including but not limited to bonding, welding, riveting, or threaded connections.

[0125] Optionally, there are two end walls 111, and the two opposite ends of the housing 110 are open, that is, they have two opposite openings. One opening can be closed by one end wall 111, and the other opening can be closed by the other end wall 111.

[0126] Some embodiments of this application are described using one end wall 111 as an example, wherein one wall portion of the housing 110 is disposed opposite to the end wall 111.

[0127] Optionally, the thickness direction z of the end wall can be the height direction of the battery cell 10. In some other embodiments, the thickness direction z of the end wall can be the width direction or the thickness direction of the battery cell 10.

[0128] The housing 110 can have various shapes, such as a cylinder or a cuboid. The shape of the housing 110 can be determined according to the specific shape of the electrode assembly 12. For example, if the electrode assembly 12 is a cylindrical structure, then the housing 110 can be a cylindrical structure; if the electrode assembly 12 is a cuboid structure, then the housing 110 can be a cuboid structure. Of course, the end wall 111 can also have various shapes, which can be set to correspond to the shape of the housing 110. For example, in Figures 3 and 4, the housing 110 is a cuboid structure, and correspondingly, the end cap is a rectangular structure.

[0129] The electrode assembly 12 is a component in the battery cell 10 where electrochemical reactions occur. The structure of the electrode assembly 12 can be various. For example, the electrode assembly 12 includes an electrode and a separator. For example, the electrode assembly 12 can be a wound structure formed by winding a positive electrode, a separator and a negative electrode, or a stacked structure formed by arranging a positive electrode, a separator and a negative electrode in layers.

[0130] Optionally, the separator is a separator membrane, and the main material of the separator membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.

[0131] The electrode assembly 12 has tabs 120 for inputting or outputting the positive or negative electrode of the electrode assembly 12. The tabs 120 are connected to the electrode terminals 14 via adapters 18 to achieve an electrical connection between the electrode assembly 12 and the electrode terminals 14. In some embodiments, the tabs 120 are located at one end of the electrode assembly 12 near the end wall 111 in the thickness direction z of the end wall; or, along the thickness direction z of the end wall, the tabs 120 are disposed on the side of the electrode assembly 12.

[0132] Optionally, the electrode assembly 12 housed within the housing 11 can be one or more. For example, in FIG3, the housing 11 of the battery cell 10 is provided with two electrode assemblies 12, which are stacked along their thickness direction. That is, the two electrode assemblies 12 are stacked along the thickness direction of the battery cell 10. Of course, in other embodiments, the electrode assembly 12 housed within the housing 11 can be one, three, four, five, six, seven, or eight, etc.

[0133] The end wall 111 includes a wall body 112 and a connecting portion 113, with at least a portion of the connecting portion 113 circumferentially disposed around the outer periphery of the wall body 112. The wall body 112 can be the main structure of the end wall 111, and the connecting portion 113 is located on the outer side of the end wall 111. The connecting portion 113 is connected to the housing 110 so that the end wall 111 can close the opening of the housing 110. Optionally, the connecting portion 113 has an annular structure, disposed around the outer periphery of the wall body 112. Optionally, the connecting portion 113 has an intermittent annular structure, disposed around the outer periphery of the wall body 112. Optionally, the connecting portion 113 has an arcuate structure, disposed around the outer periphery of the wall body 112.

[0134] Optionally, along the thickness direction z of the end wall, the side of the connecting portion 113 facing the electrode assembly 12 is in contact with and connected to the end of the housing 110. Exemplarily, the side of the connecting portion 113 facing the electrode assembly 12 is welded to the end of the housing 110. In some embodiments, along the thickness direction z of the end wall, the orthographic projection of the wall body 112 lies within the orthographic projection of the housing 110, and the orthographic projection of the connecting portion 113 at least partially overlaps with the orthographic projection of the housing 110.

[0135] For example, when assembling the battery cell 10, the electrode assembly 12 can be placed into the housing 110 first, and an electrolyte, such as an electrolyte solution, can be filled into the housing 110. Then, the connecting portion 113 of the end wall 111 is connected to the housing 110, so that the end wall 111 covers the opening of the housing 110 to close the opening of the housing 110.

[0136] Optionally, the wall body 112 may be provided with an injection hole 1123 for injecting electrolyte, such as electrolyte solution, into the battery cell 10. In some embodiments, after injection, the injection hole 1123 may be sealed by a sealing member 16, which may include a plastic nail, an aluminum nail, or other structural components.

[0137] Optionally, the wall body 112 is provided with electrode terminals 14, which are electrically connected to the tabs 120 of the electrode assembly 12. The electrode terminals 14 serve to output or input electrical energy of the battery cell 10. One end of the electrode terminal 14 is used to connect to the tabs 120 of the electrode assembly 12, and the other end is used to connect to the busbar component to realize the input or output of electrical energy of the battery cell 10.

[0138] For example, the electrode terminal 14 can be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. Of course, in some embodiments, the electrode terminal 14 can also be a composite material, that is, the electrode terminal 14 is formed by connecting two different metal materials, for example, by hot pressing or cold pressing. Optionally, the wall body 112 is provided with a terminal hole 1122, which penetrates both sides of the end wall 111 along the thickness direction z. The electrode terminal 14 is inserted into the terminal hole 1122 along the thickness direction z of the end wall, so that a portion of the electrode terminal 14 is located within the terminal hole 1122. This allows the electrode terminal 14 to connect to both the electrode assembly 12 located inside the housing 11 and the current-carrying component located outside the housing 11, thereby realizing the input or output of electrical energy from the battery cell 10.

[0139] The assembly relationship between the electrode terminal 14 and the wall body 112 is varied, including riveting, bonding, snap-fitting, or connection through other structural components. For example, the electrode terminal 14 can be riveted to the wall body 112, such as by comprising two riveted parts that clamp the body together. Alternatively, the electrode terminal 14 and the wall body 112 can be connected through other structural components, such as by the electrode terminal 14 passing through a terminal hole 1122, a pressure ring welded to the wall body 112, and the pressure ring and the wall body 112 jointly clamping a portion of the electrode terminal 14 to achieve assembly of the electrode terminal 14.

[0140] Optionally, the electrode terminal 14 can be directly connected to the tab 120 of the electrode assembly 12, such as by welding or abutting, or it can be indirectly connected to the tab 120 of the electrode assembly 12 through other components. Similarly, the connection structure between the electrode terminal 14 and the bus component can also be various, such as welding, abutting, or snap-fitting.

[0141] In some embodiments, as shown in FIG3, the battery cell 10 may further include an adapter 18 disposed within the housing 11. The adapter 18 connects the electrode terminal 14 and the tab 120 of the electrode assembly 12 to realize the electrical connection between the electrode assembly 12 and the electrode terminal 14.

[0142] In some embodiments, as shown in Figures 3 and 4, the battery cell 10 may further include a pressure relief mechanism 15 disposed on the wall body 112. The pressure relief mechanism 15 is used to release the internal pressure of the battery cell 10 when the internal pressure or temperature of the battery cell 10 reaches a predetermined value.

[0143] The step portion 114 is formed on the inner side of the end wall 111 and is protruding. In some embodiments, the step portion 114 may include two surfaces that are perpendicular or inclined to each other, one of which may abut against the end face of the housing 110 and the other may abut against the inner wall surface of the housing 110. Alternatively, one of the two surfaces may abut against the end face of the housing 110.

[0144] Optionally, the step portion 114 may be formed inside the connecting portion 113, or the step portion 114 may be formed inside the wall body 112. Optionally, a portion of the step portion 114 may be formed inside the connecting portion 113, and another portion may be formed inside the wall body 112. Exemplarily, the step portion 114 includes a first step surface 1132 formed inside the connecting portion 113 and a second step surface 1121 formed inside the wall body 112. The first step surface 1132 and the second step surface 1121 are perpendicularly disposed. The first step surface 1132 abuts against the end face of the housing 110, and the second step surface 1121 abuts against the inner wall surface of the housing 110.

[0145] The tensile strength of the step 114 at a temperature of 25℃ is Rm, and Rm satisfies: 250MPa≤Rm≤2000MPa.

[0146] In some embodiments, the tensile strength of the step portion 114 at a temperature of 25°C can be understood as the tensile strength of the step portion 114 at room temperature. In embodiments where the step portion 114 is integrally formed into the end wall 111, it can also be understood as the tensile strength of the end wall 111 at room temperature.

[0147] In some embodiments, the tensile strength Rm of the step portion 114 at a temperature of 25°C can be 250MPa, 280MPa, 300MPa, 330MPa, 350MPa, 380MPa, 400MPa, 450MPa, 500MPa, 550MPa, 600MPa, 650MPa, 700MPa, 750MPa, 800MPa, 850MPa, 900MPa, 950MPa, 1000MPa, or 1... 050MPa, 1100MPa, 1150MPa, 1200MPa, 1250MPa, 1300MPa, 1350MPa, 1400MPa, 1450MPa, 1500MPa, 1550MPa, 1600MPa, 1650MPa, 1700MPa, 1750MPa, 1800MPa, 1850MPa, 1900MPa, 1950MPa, 2000MPa, or any value between two adjacent values.

[0148] It should be understood that the tensile strength in this application embodiment refers to the maximum stress value that the material can withstand before breaking. The testing method for the tensile strength Rm of the step portion 114 in this application embodiment at a temperature of 25°C can be selected according to the actual application. For example, the national standard GB / T228.1-2010 can be used to test the tensile strength Rm at room temperature of 25°C. Optionally, the tensile strength can be tested on the entire end wall 111, or only on the step portion 114 of the end wall 111.

[0149] In some embodiments, the battery cell 10 further includes an insulating member 13. The insulating member 13 covers at least a portion of the outer peripheral surface of the housing 110, and the insulating member 13 is connected to the side of the connection portion 113 opposite to the electrode assembly 12. The insulating member 13 is an insulating structure covering at least a portion of the outer peripheral surface of the housing 110. Optionally, the insulating member 13 can be a film structure, for example, the insulating member 13 can be a blue film. Optionally, the insulating member 13 can cover the outer side and bottom of the housing 110.

[0150] In some embodiments, a portion of the insulating member 13 may be disposed on the side of the end wall 111 opposite to the electrode assembly 12. Optionally, the portion of the insulating member 13 located on the side of the end wall 111 opposite to the electrode assembly 12 may be interconnected with the end wall 111, for example, by bonding the two together.

[0151] The phrase "the insulating member 13 is connected to the side of the connecting portion 113 opposite to the electrode assembly 12" can be understood as meaning that the portion of the insulating member 13 located on the side of the end wall 111 opposite to the electrode assembly 12 can at least be connected to the connecting portion 113. Optionally, in some embodiments, the portion of the insulating member 13 located on the side of the end wall 111 opposite to the electrode assembly 12 can be connected to the connecting portion 113 and also connected to the wall body 112.

[0152] For example, the main part of the insulating member 13 covers the outer periphery of the housing 110. Along the thickness direction z of the end wall, the portion of the insulating member 13 that extends beyond the housing 110 is bent to the outside of the end wall 111, and the extended portion is connected to the connecting portion 113, or the extended portion is connected to the connecting portion 113 and the wall body 112.

[0153] The first surface 1120 may be the outer surface of the wall body 112. In some embodiments, the first surface 1120 may be the surface of the wall body 112 that is furthest away from the electrode assembly 12. In some embodiments, the end wall 111 is provided with an electrode terminal 14, which may be located in the area where the first surface 1120 is located.

[0154] Taking the thickness direction z of the end wall as the height direction of the battery cell 10 as an example, "the distance between the side of the connecting part 113 away from the electrode assembly 12 and the first surface 1120 is less than or equal to 0.5mm". The height difference between the outer side of the connecting part 113 and the outer side of the wall body 112 is not greater than 0.5mm. For example, this value can be 0, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm or any value between two adjacent values.

[0155] Optionally, part or all of the connecting portion 113 on the side opposite to the electrode assembly 12 may protrude from the first surface 1120, and the protrusion size is no greater than 0.5 mm, as shown by reference numeral h1 in FIG8.

[0156] Optionally, part or all of the connecting portion 113 on the side opposite to the electrode assembly 12 may be recessed into the first surface 1120, and the size of the recess is not greater than 0.5 mm, as shown by reference numeral h2 in FIG10.

[0157] Optionally, part or all of the connecting portion 113 on the side opposite to the electrode assembly 12 may be flush with the first surface 1120.

[0158] Optionally, a portion of the connecting portion 113 on the side opposite to the electrode assembly 12 protrudes from the first surface 1120, while another portion is recessed into the first surface 1120.

[0159] Optionally, a portion of the connecting portion 113 on the side opposite to the electrode assembly 12 protrudes from the first surface 1120, a portion is recessed in the first surface 1120, and the remaining portion is flush with the first surface 1120.

[0160] It should be noted that in related technologies, especially in the battery cell 10 where the end wall 111 is welded to the casing 110, the end wall 111 has a stepped design, and a protrusion is formed on the outer side of the end wall 111. The protrusion is thinned or reduced in size through machining to reduce the protrusion size to form the connecting part 113. In particular, by reducing the protrusion size of the protrusion through machining, the distance difference between the machined part and the first surface 1120 is not greater than 0.5mm. For example, the height of the protrusion is reduced and a smaller protrusion is present, or the height of the protrusion is reduced to be flush with the first surface 1120, or the height of the protrusion is reduced to be recessed into the first surface 1120.

[0161] In the above solution, on the one hand, by limiting the range of the room temperature tensile strength Rm of the stepped portion 114, and the range satisfies 250MPa≤Rm≤2000MPa, the deformation resistance of this part can be high to resist the expansion of the electrode assembly, making the joint between the end wall 111 and the shell 110 less likely to be damaged, thereby making the battery cell more reliable. On the other hand, by processing the part located on the outer periphery of the wall body 112, the distance difference between the side of the connecting portion 113 away from the electrode assembly 12 and the first surface 1120 of the wall body 112 is no more than 0.5mm. At the battery device level, it can effectively improve the problem of damage to the end wall 111 structure caused by external structural extrusion, or damage to structural components located on the outside of the end wall 111, such as the insulation failure caused by the insulation component 13 located on the outside of the end wall 111 being punctured by extrusion, thereby effectively improving the reliability of the battery device 100. In particular, in the battery cell 10 where the end wall 111 is welded to the housing 110, the end wall 111 has a stepped design. Through machining and other processes, the protrusion on the outer side of the end wall 111 is thinned to form the connection part 113, which facilitates the connection of the insulating part 13 and reduces the risk of damage to the insulating part 13 due to the compression of the external structure, thereby improving the reliability of the battery device 100.

[0162] According to some embodiments of this application, along the thickness direction z of the end wall, the distance between the side of the connecting portion 113 away from the electrode assembly 12 and the first surface 1120 is less than or equal to 0.3 mm.

[0163] In some embodiments, the height difference between the outer surface of the connecting portion 113 and the outer surface of the wall body 112 is no greater than 0.3 mm. For example, this value can be 0, 0.1 mm, 0.2 mm, 0.3 mm or any value between two adjacent values.

[0164] Optionally, part or all of the connecting portion 113 on the side opposite to the electrode assembly 12 may protrude from the first surface 1120, and the protrusion size is no greater than 0.3 mm, as shown by reference numeral h1 in FIG8.

[0165] Optionally, part or all of the connecting portion 113 on the side opposite to the electrode assembly 12 may be recessed into the first surface 1120, and the size of the recess is not greater than 0.3 mm, as shown by reference numeral h2 in FIG10.

[0166] In the above solution, by processing the connecting portion 113 located on the outer periphery of the wall body 112, the distance difference between the side of the connecting portion 113 away from the electrode assembly 12 and the first surface 1120 of the wall body 112 is no greater than 0.3mm. At the battery device level, this can further and effectively improve the problem of damage to the end wall 111 structure caused by external structural extrusion, or damage to structural components located on the outside of the end wall 111, such as the insulation failure caused by the insulation component 13 located on the outside of the end wall 111 being punctured by extrusion. This effectively improves the reliability of the battery device 100.

[0167] According to some embodiments of this application, the connecting portion 113 on the side opposite to the electrode assembly 12 includes a second surface 1130, which protrudes from the first surface 1120 along the direction from the electrode assembly 12 to the end wall 111.

[0168] Please refer to Figures 5-8. Figure 6 is a schematic diagram of the internal structure of the battery cell 10 in some embodiments of this application. Figure 7 is an enlarged view of point B in Figure 6. Figure 8 is a schematic diagram of the partial structure of the end wall 111 and the housing 110 in some embodiments of this application.

[0169] In some embodiments, the outer surface of the connecting portion 113 has a second surface 1130, which protrudes from the first surface 1120 along the direction from the electrode assembly 12 to the end wall 111, and the insulating member 13 is connected to the second surface 1130. Optionally, the insulating member 13 is connected to the second surface 1130 and extends to the first surface 1120, and the portion of the insulating member 13 extending to the first surface 1120 may be connected to the first surface 1120.

[0170] Optionally, referring to Figure 8, along the direction from the electrode assembly 12 to the end wall 111, the value of the dimension h1 of the second surface 1130 protruding from the first surface 1120 can be 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm or any value between two adjacent values, or any value between 0 and 0.1mm.

[0171] Optionally, the value of h1 can also be 0.1mm, 0.2mm, 0.3mm or any value between two adjacent values, or any value between 0 and 0.1mm.

[0172] In the above scheme, along the direction from the electrode assembly 12 to the end wall 111, the second surface 1130 of the connecting portion 113 protrudes from the first surface 1120, and the size of the second surface 1130 protruding from the first surface 1120 is no greater than 0.5 mm. At the battery device level, this effectively reduces the risk of insulation failure caused by local puncture of the end wall 111 and the insulating component 13 located outside the end wall 111 due to external structural compression, thus effectively improving the reliability of the battery device 100. In particular, in the battery cell 10 where the end wall 111 is welded to the housing 110, the end wall 111 has a stepped design. Through machining and other processes, the protrusion on the outer side of the end wall 111 is thinned to form the second surface 1130, and the size of the second surface 1130 protruding from the first surface 1120 is no greater than 0.5 mm. This reduces the risk of structural damage to the insulating component 13 caused by external structural compression, thereby improving the reliability of the battery device 100.

[0173] According to some embodiments of this application, the connecting portion 113 on the side opposite to the electrode assembly 12 includes a third surface 1131, and a first surface 1120 protrudes from the third surface 1131 along the direction from the electrode assembly 12 to the end wall 111.

[0174] Please refer to Figures 5, 9 and 10. Figure 9 is an enlarged view of point C in Figure 6, and Figure 10 is a partial structural schematic diagram of the end wall 111 and the housing 110 in some embodiments of this application.

[0175] In some embodiments, the outer surface of the connecting portion 113 has a third surface 1131. Along the direction from the electrode assembly 12 to the end wall 111, the first surface 1120 protrudes from the third surface 1131, and the insulating member 13 is connected to the third surface 1131. That is, the third surface 1131 is recessed relative to the first surface 1120.

[0176] Optionally, the insulating member 13 is connected to the third surface 1131 and extends to the first surface 1120, and the portion of the insulating member 13 extending to the first surface 1120 can be connected to the first surface 1120.

[0177] Optionally, referring to Figure 10, along the direction from the electrode assembly 12 to the end wall 111, the value of the dimension h2 of the first surface 1120 protruding from the third surface 1131 can be 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm or any value between two adjacent values, or any value between 0 and 0.1mm.

[0178] Optionally, the value of h2 can also be 0.1mm, 0.2mm, 0.3mm or any value between two adjacent values, or any value between 0 and 0.1mm.

[0179] Optionally, in some embodiments, the protrusion on the outer side of the end is machined to thin it and form a third surface 1131. During the machining process, the machining execution end can cover the first surface 1120 and form a groove on the first surface 1120. The bottom wall of the groove can be flush with the third surface 1131.

[0180] Optionally, in some embodiments, the protrusion on the outer side of the end is machined to thin it and form a third surface 1131. During the machining process, the machining execution end can act only on the protrusion on the outer side of the end.

[0181] In the above solution, the outer side of the connecting portion 113 has a third surface 1131 that is recessed relative to the first surface 1120, and the size of the recess is no greater than 0.5 mm. This effectively reduces the risk of insulation failure caused by local puncture due to external pressure on the end wall 111 and the insulating component 13 located on the outer side of the end wall 111, thus effectively improving the reliability of the battery device 100. In particular, in the battery cell 10 where the end wall 111 is welded to the housing 110, the end wall 111 has a stepped design. Through machining and other processes, the steps are thinned to form the third surface 1131 that is recessed relative to the first surface 1120, and the size of the recess of the third surface 1131 is no greater than 0.5 mm. This reduces the risk of damage to the insulating component 13 due to external pressure, thereby improving the reliability of the battery device 100.

[0182] According to some embodiments of this application, the side of the connection portion 113 opposite to the electrode assembly 12 includes a fourth surface, which is flush with the first surface 1120.

[0183] In some embodiments, the outer surface of the connecting portion 113 includes a fourth surface. Optionally, the entire outer surface of the connecting portion 113 is the fourth surface, or a portion of the outer surface of the connecting portion 113 is the fourth surface. The fourth surface is flush with the first surface 1120, and the two are on the same plane.

[0184] In the above solution, the outer side of the connecting portion 113 has a fourth surface flush with the first surface 1120, and the insulating member 13 is connected to the fourth surface. This effectively reduces the risk of insulation failure caused by local puncture due to external pressure on the end wall 111 and the insulating member 13 located on the outer side of the end wall 111, thus effectively improving the reliability of the battery device 100. In particular, in the battery cell 10 where the end wall 111 is welded to the housing 110, the end wall 111 has a stepped design. Through machining and other processes, the protrusion on the outer side of the end wall 111 is thinned to form a fourth surface flush with the first surface 1120. This reduces the risk of structural damage to the insulating member 13 caused by external pressure, thereby improving the reliability of the battery device 100.

[0185] According to some embodiments of this application, the connecting portion 113 on the side opposite to the electrode assembly 12 includes a second surface 1130 and a third surface 1131. The second surface 1130 is connected to the third surface 1131. Along the direction of the electrode assembly 12 pointing to the end wall 111, the second surface 1130 protrudes from the first surface 1120, and the first surface 1120 protrudes from the third surface 1131.

[0186] Please refer to Figure 5. The outer surface of the connecting part 113 includes a second surface 1130 and a third surface 1131. The second surface 1130 protrudes from the first surface 1120, and the first surface 1120 protrudes from the third surface 1131.

[0187] In some embodiments, the second surface 1130 and the third surface 1131 may be configured with an inclined transition, a vertical transition, or a circular arc transition.

[0188] Optionally, as shown in Figure 4, the second surface 1130 and the third surface 1131 are connected to each other, and together they enclose the wall body 112 in a circle.

[0189] In the above scheme, the outer side of the connecting part 113 includes a second surface 1130 and a third surface 1131. The second surface 1130 protrudes from the first surface 1120, and the protrusion size is no greater than 0.5mm. The third surface 1131 is recessed from the first surface 1120, and the recess size is no greater than 0.5mm. On the one hand, this makes the outer side of the connecting part 113 relatively flat with the outer side of the wall body 112, which can effectively reduce the risk of insulation failure caused by the end wall 111 and the insulating member 13 located on the outer side of the end wall 111 being squeezed by the external structure and partially punctured. This can effectively improve the reliability of the battery device 100. On the other hand, the unevenness of the outer periphery of the end wall 111 can effectively improve the structural strength of the end wall 111, which is beneficial to the improvement of the structural strength of the battery cell 10 and the improvement of the reliability of the battery device 100.

[0190] According to some other embodiments of this application, please refer to FIG11, which is a schematic diagram of the wall body 112 and the connecting portion 113 in some other embodiments of this application.

[0191] The connecting part 113 has an annular structure. The inner periphery of the connecting part 113 is connected to the wall body 112. Along the direction from the inner periphery of the connecting part 113 to the outer periphery of the connecting part 113, the distance between the side of the connecting part 113 away from the electrode assembly 12 and the electrode assembly 12 in the thickness direction z of the end wall gradually decreases.

[0192] In some embodiments, the connecting portion 113 is arranged around the wall body 112, and the direction from the inner periphery of the connecting portion 113 to the outer periphery of the connecting portion 113 is inclined, that is, the lowest point of the outer side of the connecting portion 113 is away from the wall body 112.

[0193] In the above scheme, along the direction from the inner periphery of the connecting portion 113 to the outer periphery of the connecting portion 113, the distance between the side of the connecting portion 113 away from the electrode assembly 12 and the electrode assembly 12 in the thickness direction z of the end wall gradually decreases. This makes the outer side of the connecting portion 113 inclined, which allows the insulating component 13 to smoothly transition at the junction of the housing 110 and the end wall 111, reducing the generation of burrs and the risk of damage to other structural components of the battery cell. At the same time, it also reduces the risk of stress concentration and structural damage to the insulating component 13, resulting in high reliability of the battery cell 10 and improving the reliability of the battery device 100. In particular, in the battery cell 10 where the end wall 111 is welded to the housing 110, the end wall 111 has a stepped design. Through machining and other processes, the protrusion on the outer side of the end wall 111 is thinned at a certain angle, making the outer side of the connecting portion 113 inclined. This reduces the risk of local structural damage to the insulating component 13, thereby improving the reliability of the battery cell 10.

[0194] According to some embodiments of this application, the hardness of the connecting portion 113 is greater than the hardness of the wall body 112.

[0195] Hardness can be defined as the ability of a material to resist the indentation of a hard object onto its surface. In some embodiments, the hardness of the connection 113 and the wall body 112 can be tested by methods such as indentation or scoring.

[0196] In the above solution, by setting the hardness of the connecting part 113 to be greater than the hardness of the wall body 112, the connection quality between the shell 110 and the end wall 111 can be high, reducing the risk of the end wall 111 and the shell 110 separating due to impact, thus improving the reliability of the battery cell 10 and the battery device 100. In particular, in the battery cell 10 where the end wall 111 and the shell 110 are welded together, the end wall 111 has a stepped design. By thinning the protrusion on the outer side of the end wall 111 through machining and other processes, the risk of insulation failure due to local puncture caused by external pressure on the end wall 111 and the insulating part 13 located on the outer side of the end wall 111 can be reduced. On the other hand, it can also increase the hardness of the local structure of the end wall 111, resulting in a high connection quality between the shell 110 and the end wall 111, which is beneficial to improving the reliability of the battery device 100.

[0197] According to some embodiments of this application, please refer to Figures 8 and 9. The connecting portion 113 is connected to the housing 110 through the first connecting portion 17. The stepped portion 114 includes a first stepped surface 1132 and a second stepped surface 1121 that are connected to each other. The first stepped surface 1132 is formed on the side of the connecting portion 113 facing the electrode assembly 12, along the radial direction of the end wall 111. The second stepped surface 1121 is formed on the side of the wall body 112 facing the inner wall surface of the housing 110, along the thickness direction z of the end wall. The housing 110 has a first end face facing the connecting portion 113. The first connecting portion 17 is located between the first end face and the first stepped surface 1132.

[0198] In some embodiments, the step portion 114 includes a first step surface 1132 and a second step surface 1121 that are connected to each other. Optionally, the first step surface 1132 and the second step surface 1121 may be arranged vertically, that is, the plane containing the first step surface 1132 is parallel to the plane containing the second step surface 1121. Optionally, the first step surface 1132 and the second step surface 1121 may be arranged at an angle.

[0199] In some embodiments, the first step surface 1132 and the second step surface 1121 can be directly connected or connected by a transition. For example, the first step surface 1132 and the second step surface 1121 are connected by a rounded corner transition.

[0200] In some embodiments, the first joint 17 is a portion connecting the housing 110 and the connecting portion 113. The first joint 17 can be a structure formed by welding, bonding, riveting, or threaded connection. Exemplarily, the first joint 17 is a weld mark located between the housing 110 and the connecting portion 113, and the weld mark is annular along the circumference of the connecting portion 113. Exemplarily, the first joint 17 is an adhesive structure located between the housing 110 and the connecting portion 113, such as an adhesive layer formed after glue dries.

[0201] The first step surface 1132 is the surface of the step portion 114 used to abut against the end face of the housing 110. The first step surface 1132 and the second step surface 1121 can together form the step portion 114 to achieve ground contact with the housing 110. In some embodiments, the first step surface 1132 can be part or all of the inner side surface of the connecting portion 113, and the first end face can be part or all of the surface of the peripheral wall of the housing 110 facing the end wall 111.

[0202] For example, when assembling the end cap and the housing 110, the end cap is disposed at the opening of the housing 110 such that the first stepped surface 1132 is in contact with the first end face, and the first stepped surface 1132 and the first end face are welded together along the side of the housing 11 by a welding device.

[0203] In the above scheme, the connecting part 113 is connected to the housing 110 through the first connecting part 17, and the first connecting part 17 can be disposed on the side of the housing 11 between the first end face and the first step surface 1132, which can reduce the difficulty of connecting the connecting part 113 and the housing 110 to each other, making the manufacturing efficiency of the battery cell 10 high and improving the manufacturing efficiency of the battery device 100.

[0204] According to some embodiments of this application, the first joint 17 is a solder mark formed between the connecting portion 113 and the housing 110.

[0205] In some embodiments, the connecting portion 113 and the housing 110 are joined together by a welding process to form a first joint portion 17, which is a weld mark formed by welding.

[0206] In the above scheme, the connecting part 113 and the housing 110 are connected to each other by welding, and the welding direction can be the side of the battery cell 10. Therefore, the connection between the connecting part 113 and the housing 110 is reliable, and the connection between the connecting part 113 and the housing 110 is easy and efficient.

[0207] According to some embodiments of this application, as shown in Figures 8 and 10, the second step surface 1121 abuts against the inner wall surface of the housing 110.

[0208] In some embodiments, the second step surface 1121 may be the surface of the wall body 112 facing the inner wall surface of the housing 110 along the radial direction of the end wall 111.

[0209] The radial direction of end wall 111 is perpendicular to the axial direction of end wall 111, and the axial direction of end wall 111 may be parallel to the thickness direction z of end wall. In some embodiments, the second step surface 1121 may be part or all of the outer peripheral surface of the wall body 112. In some embodiments, the connecting portion 113 may be disposed on the second step surface 1121. In some embodiments, the first step surface 1132 of the connecting portion 113, that is, the inner side surface of the connecting portion 113, may be connected to the second step surface 1121.

[0210] "The second step surface 1121 is in contact with the inner wall surface of the shell 110" can be understood as the outer peripheral surface of the wall body 112 being in contact with the inner wall surface of the shell 110.

[0211] Optionally, the second step surface 1121 may abut against the inner wall surface of the housing 110.

[0212] In the above scheme, the second step surface 1121 of the wall body 112 can contact the inner wall of the housing 110, which can play the role of positioning the end wall 111 and the housing 110, so that the assembly accuracy of the end wall 111 and the housing 110 is high, reducing the difficulty of connecting the connecting part 113 and the housing 110, making the manufacturing efficiency of the battery cell 10 high, and thus making the manufacturing efficiency of the battery device 100 high.

[0213] In other embodiments, there may be a gap between the second step surface 1121 and the inner wall surface of the housing 110.

[0214] According to some embodiments of this application, the insulating member 13 covers at least a portion of the outer peripheral surface of the housing 110, and the insulating member 13 is connected to the side of the connecting portion 113 opposite to the electrode assembly 12.

[0215] The insulating element 13 is an insulating structure that covers at least a portion of the outer peripheral surface of the housing 110. Optionally, the insulating element 13 can be a film structure, for example, the insulating element 13 can be a blue film. Optionally, the insulating element 13 can cover the outer side surface and bottom of the housing 110.

[0216] According to some embodiments of this application, see Figures 7 and 9, a portion of the insulating member 13 is connected to the first surface 1120.

[0217] In some embodiments, the insulating member 13 is connected to the connecting portion 113, and the insulating member 13 extends to and is connected to the first surface 1120.

[0218] Optionally, the insulating element 13 and the first surface 1120 can be stacked on top of each other, for example, the insulating element 13 can overlap the first surface 1120. Optionally, the insulating element 13 can be bonded to the first surface 1120.

[0219] In the above solution, by connecting a portion of the insulating component 13 to the first surface 1120, the connection area between the end wall 111 and the insulating component 13 can be increased, thereby improving the reliability of the connection quality between the insulating component 13 and the outer casing 11, which is beneficial to improving the reliability of the external insulation of the battery cell 10 and the overall reliability of the battery cell 10.

[0220] According to some embodiments of this application, referring to FIG4, a portion of the insulating member 13 is connected to the first surface 1120. The battery cell 10 also includes an electrode terminal 14, which is disposed on the first surface 1120 and electrically connected to the electrode assembly 12.

[0221] The electrode terminal 14 serves to output or input electrical energy of the battery cell 10. One end of the electrode terminal 14 is used to connect to the tab 120 of the electrode assembly 12, and the other end is used to connect to the busbar component to realize the input or output of electrical energy of the battery cell 10.

[0222] In some embodiments of this application, the electrode terminal 14 is disposed on the wall body 112 and located in the region where the first surface 1120 is located. Optionally, the orthographic projection of the electrode terminal 14 along the thickness direction z of the end wall may fall on the first surface 1120.

[0223] Alternatively, in some other embodiments, the electrode terminal 14 may be disposed on other walls of the housing 11, such as the bottom wall or side wall of the housing 110.

[0224] According to some other embodiments of this application, there are two end walls 111, which are opposite to each other and connected to the housing 110 respectively along the thickness direction z of the end walls.

[0225] In some embodiments, along the thickness direction z of the end walls, the two opposite ends of the housing 110 are open, and there are two end walls 111. The two end walls 111 are respectively connected to the housing 110 to close the two opposite openings of the housing 110 respectively.

[0226] In the above scheme, there are two end walls 111, which are opposite to each other. This can effectively improve the problem of local damage to the insulating component 13 caused by interference from external structures at both ends of the outer casing 11, so that the insulation reliability of the battery cell 10 is high, which in turn helps to improve the reliability of the battery device 100.

[0227] According to some embodiments of this application, the following condition is met: 450MPa≤Rm≤800MPa.

[0228] In some embodiments, the tensile strength Rm of the step portion 114 at a temperature of 25°C ranges from not less than 450 MPa to not more than 800 MPa.

[0229] In some embodiments, the tensile strength Rm of the step portion 114 at a temperature of 25°C can be 450MPa, 500MPa, 550MPa, 600MPa, 650MPa, 700MPa, 750MPa, 800MPa or any value between two adjacent values.

[0230] In the above scheme, on the one hand, limiting the tensile strength Rm of the stepped portion 114 at room temperature to not less than 450MPa ensures that the end wall 111 has strong deformation capacity to resist the expansion of the electrode assembly, making this part less prone to damage. This, in turn, makes the joint between the end wall 111 and the shell 110 less prone to damage, reducing the risk of cracking of the shell 11 and thus improving the structural stability and service life of the battery cell. On the other hand, controlling the tensile strength Rm of the end wall 111 at room temperature to not be too large reduces the difficulty of material selection and processing for the end wall 111, saving costs and facilitating processing.

[0231] According to some embodiments of this application, the material of the step portion 114 includes one of the following materials: steel, copper alloy, titanium alloy, and nickel alloy.

[0232] In the above scheme, the material of the step portion 114 includes one of steel, copper alloy, titanium alloy and nickel alloy, so that the end wall 111 has greater strength, can meet the strength requirements of the battery cell 10 shell 11, and is easy to process and has a lower cost.

[0233] According to some embodiments of this application, the material of the step portion 114 includes stainless steel or carbon steel.

[0234] If the step portion 114 is made of stainless steel, its structural strength is high, which can generally meet the tensile strength Rm requirement under the aforementioned room temperature conditions. Furthermore, stainless steel is less prone to rusting, which, compared to other materials, improves the reliability of the joint between the end wall 111 and the shell 110, reducing the risk of cracking of the outer shell 11. If the step portion 114 is made of carbon steel, its structural strength is high, making it easy to meet the tensile strength Rm requirement under the aforementioned room temperature conditions.

[0235] According to some embodiments of this application, the material of the housing 110 is the same as the material of the step portion 114.

[0236] In some embodiments, the material of the housing 110 is the same as the material of the stepped portion 114. That is, the outer shell 11 and the end wall 111 can both meet the tensile strength Rm requirement under the above-mentioned room temperature conditions, which can improve the reliability of the joint between the end wall 111 and the housing 110 and reduce the risk of cracking of the outer shell 11. At the same time, the material of the end wall 111 is the same as the material of the housing 11, which can reduce the difficulty of connecting the end wall 111 and the housing 11, for example, the difficulty of welding the two together is low, which is conducive to improving the manufacturing efficiency of the battery cell 10.

[0237] For example, the end wall 111 is made of steel and the outer shell 11 is made of steel. The end wall 111 and the outer shell 110 can be effectively combined into one unit through welding process, and the structure has high strength. This allows the outer shell 11 of the battery cell 10 to be thinner, so as to accommodate more electrochemical substances, thereby improving the volumetric energy density of the battery cell 10.

[0238] In some embodiments, the end wall 111 is made of steel, and a step is formed on the inner side of the end wall 111 by stamping, that is, forming the second step surface 1121 of the wall body 112 and the first step surface 1132 of the connecting part 113, so that the second step surface 1121 can contact the inner wall surface of the housing 110, and the first step surface 1132 can contact the first end surface of the housing 110. The end wall 111 and the housing 110 are joined together by side welding. Since the end wall 111 is processed by stamping, a protrusion corresponding to the step is formed on the outer side of the end wall 111. The protrusion is machined to form the connecting part 113, so that the outer surface of the end wall 111 is relatively flat. When the part connected to the insulating member 13 is a concave-convex surface, the height difference between the concave and convex surfaces can not exceed 0.5 mm under the action of machining. Optionally, the height difference between the concave and convex surfaces can not exceed 0.3 mm under the action of machining.

[0239] According to some embodiments of this application, some embodiments of this application also provide a battery device 100, which includes the battery cell 10 provided above.

[0240] As shown in Figure 2, the battery device 100 may also include a housing 20, in which the battery cells 10 are housed.

[0241] In some embodiments, the housing 20 may include a first housing body 21 and a second housing body 22, the first housing body 21 and the second housing body 22 covering each other, the first housing body 21 and the second housing body 22 together defining an assembly space for accommodating the battery cell 10.

[0242] Optionally, the second box body 22 can be a hollow structure with one end open, and the first box body 21 can be a plate-like structure. The first box body 21 covers the open side of the second box body 22 so that the first box body 21 and the second box body 22 together define the assembly space; the first box body 21 and the second box body 22 can also be hollow structures with one side open, and the open side of the first box body 21 covers the open side of the second box body 22.

[0243] Of course, the box 20 formed by the first box body 21 and the second box body 22 can be of various shapes, such as a cylinder or a cuboid. For example, in Figure 2, the box 20 is a cuboid structure.

[0244] Optionally, the battery cell 10 disposed within the housing 20 can be one or more. For example, in Figure 2, the housing 20 of the battery device 100 contains multiple battery cells 10, which can be connected in series, parallel, or a combination thereof. A combination thereof means that some of the battery cells 10 are connected in series and others in parallel. Multiple battery cells 10 can be directly connected in series, parallel, or a combination thereof, and then the entire assembly of the multiple battery cells 10 is housed within the housing 20. Alternatively, the battery device 100 can also consist of multiple battery cells 10 first connected in series, parallel, or a combination thereof to form a battery module, and then these battery modules are connected in series, parallel, or a combination thereof to form a whole, which is then housed within the housing 20.

[0245] The battery device 100 may also include other structures. For example, the battery device 100 may also include a busbar component that connects multiple battery cells 10 to achieve electrical connection between the multiple battery cells 10.

[0246] It should be noted that in some embodiments, the battery device 100 may not have a housing 20. The battery device 100 includes multiple battery cells 10, and the battery device 100 composed of multiple battery cells 10 can be directly mounted onto the electrical device to provide power to the electrical device through the multiple battery cells 10. That is, the housing 20 can be part of the electrical device. Taking a vehicle 1000 as an example, the housing 20 can be part of the chassis structure of the vehicle 1000. For example, a portion of the housing 20 can be at least a part of the floor of the vehicle 1000, or a portion of the housing 20 can be at least a part of the crossbeams and longitudinal beams of the vehicle 1000.

[0247] Some embodiments of this application also provide an electrical device, which includes the battery cell 10 provided above and / or the battery device 100 provided above, wherein the battery cell 10 is used to provide electrical energy.

[0248] The electrical device can be any of the aforementioned devices or systems that utilize battery cells 10 and / or battery devices 100. For example, the electrical device can be a vehicle 1000, which can be a range-extended vehicle 1000, a pure electric vehicle 1000, or a gasoline-powered vehicle 1000. The electrical energy provided by the battery cells 10 can be used to meet the power needs of the vehicle 1000 during startup, navigation, and operation.

[0249] According to some embodiments of this application, a method for manufacturing a battery cell is also provided. Please refer to FIG12, which is a flowchart of a method for manufacturing a battery cell in some embodiments of this application.

[0250] The method for manufacturing a single battery cell 2000 includes the following steps:

[0251] S1. Provide an outer casing 11, which includes a housing 110 and an end wall 111. At least a portion of the end wall 111 is formed by machining. The end wall 111 includes a wall body 112 and a connecting portion 113 that is at least partially circumferentially disposed around the outer periphery of the wall body 112. A stepped portion 114 is formed on the inner side of the end wall 111. The tensile strength of the stepped portion 114 at a temperature of 25°C is Rm, which satisfies 250MPa≤Rm≤2000MPa. Along the thickness direction z of the end wall, the outer side of the wall body 112 has a first surface 1120. The distance between the outer side of the connecting portion 113 and the first surface 1120 is less than or equal to 0.5mm.

[0252] S2. Place the electrode assembly 12 inside the housing 110;

[0253] S3. The step portion 114 abuts against the housing 110, and the connecting portion 113 is connected to the housing 110 to close the opening of the housing 110.

[0254] In some embodiments, the material of the end wall 111 can be selected to satisfy a tensile strength Rm of not less than 250 MPa and not more than 2000 MPa at a temperature of 25°C, such as steel.

[0255] In some embodiments, at least a portion of the end wall 111 is formed by machining; alternatively, the connecting portion 113 of the end wall 111 is formed by machining. Alternatively, the entire end wall 111 may be formed by machining a plate.

[0256] For example, the raw material of the end wall 111 can be a steel plate structure, and the wall body 112, the step portion 114 and the protrusion are formed by stamping process. On the side of the end wall 111 away from the electrode assembly 12, that is, on the outer side of the end wall 111, the protrusion on the outer side of the end wall 111 is thinned by machining or other processes to form the connecting portion 113.

[0257] For example, the end wall 111 can be made of steel plate structure, and the side of the end wall 111 facing the electrode assembly 12 or the inner side of the end wall 111 can be directly machined to form the wall body 112, the connecting part 113 and the step part 114. In this case, the side of the connecting part 113 away from the electrode assembly 12 can be flush with the side of the wall body 112 away from the electrode assembly 12.

[0258] According to some embodiments of this application, step S1 of providing the housing 11 includes:

[0259] The wall body 112, the stepped portion 114, and the protrusions provided on the outer periphery of the wall body 112 are formed by stamping.

[0260] The protrusion on the side of the end wall 111 opposite to the electrode assembly 12 is machined to form the connecting portion 113.

[0261] That is, the protrusion is machined on the outside of the end wall 111 to form the connecting part 113.

[0262] According to some embodiments of this application, step S1 of providing the housing 11 includes:

[0263] On the side of the end wall 111 facing the electrode assembly 12, a connecting portion 113 and a stepped portion 114 are formed by machining.

[0264] That is, the end wall 111 is machined on the inside to form the stepped portion 114 and the connecting portion 113, for example, by turning the stepped portion 114 and the connecting portion 113.

[0265] According to some embodiments of this application, the method 2000 for manufacturing a single battery cell includes the following steps:

[0266] The insulating element 13 covers at least a portion of the outer periphery of the housing 110, and the insulating element 13 is connected to the connection portion 113 on the side opposite to the electrode assembly 12.

[0267] According to some embodiments of this application, a battery cell 10 is also provided, as shown in Figures 3-11.

[0268] The battery cell 10 includes a casing 11, an electrode assembly 12, an insulating component 13, electrode terminals 14, and a pressure relief mechanism 15.

[0269] In some embodiments, the tensile strength Rm of the outer casing 11 at a temperature of 25°C satisfies 250MPa≤Rm≤2000MPa. Optionally, 450MPa≤Rm≤800MPa. Exemplarily, the outer casing 11 can be a steel casing.

[0270] The outer casing 11 includes a housing 110 and an end wall 111. The housing 110 has an opening, and the end wall 111 includes a wall body 112 and a connecting portion 113. Along the thickness direction z of the end wall, the wall body 112 has a first surface 1120 facing away from the electrode assembly 12. At least a portion of the connecting portion 113 is arranged around the outer periphery of the wall body 112, and the connecting portion 113 is connected to the housing 110 to close the opening. The electrode assembly 12 is disposed within the outer casing 11. Electrode terminals 14 are disposed on the wall body 112 and electrically connected to the electrode assembly 12, and a pressure relief mechanism 15 is disposed on the wall body 112. The electrode terminals 14 and the pressure relief mechanism 15 are located in the region corresponding to the first surface 1120.

[0271] A stepped portion 114 is formed on the inner side of the end wall 111. The stepped portion 114 includes a first stepped surface 1132 and a second stepped surface 1121. Referring to Figures 8 and 10, on the inner side of the end wall 111, the wall body 112 has a second stepped surface 1121 facing the inner wall surface of the housing 110, and the connecting portion 113 has a first stepped surface 1132 facing the electrode assembly 12. The first stepped surface 1132 and the second stepped surface 1121 together form a step to be able to engage with the end of the housing 110. The second stepped surface 1121 contacts the inner wall surface of the housing 110, and the first stepped surface 1132 contacts the first end face of the housing 110.

[0272] The end wall 111 and the housing 110 can be joined by a welding process. Optionally, the welding equipment welds the portion between the first step surface 1132 and the first end face along the side of the battery cell 10 (the side is perpendicular to the thickness direction z of the end wall) to form a first joint 17 between the first step surface 1132 and the first end face. The first joint 17 is a weld mark.

[0273] The insulating element 13 may be a blue film. The insulating element 13 covers at least a portion of the outer peripheral surface of the housing 110, and the insulating element 13 is connected to the side of the connecting portion 113 opposite to the electrode assembly 12. In some embodiments, a portion of the insulating element 13 is also connected to the first surface 1120.

[0274] The distance between the side of the connecting portion 113 away from the electrode assembly 12 and the first surface 1120 is less than or equal to 0.5 mm.

[0275] Optionally, part or all of the connecting portion 113 on the side opposite to the electrode assembly 12 may protrude from the first surface 1120, and the protrusion dimension is no greater than 0.5 mm. For example, referring to FIG8, the connecting portion 113 on the side opposite to the electrode assembly 12 includes a second surface 1130. Along the direction from the electrode assembly 12 to the end wall 111, the second surface 1130 protrudes from the first surface 1120. The value of the dimension h1 by which the second surface 1130 protrudes from the first surface 1120 can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, or any value between two adjacent values, or any value between 0 and 0.1 mm. In some embodiments, the value of h1 may also be 0.1 mm, 0.2 mm, 0.3 mm, or any value between two adjacent values, or any value between 0 and 0.1 mm.

[0276] Optionally, part or all of the connecting portion 113 on the side opposite to the electrode assembly 12 may be recessed into the first surface 1120, and the size of the recess is not greater than 0.5 mm. For example, referring to FIG10, the side of the connecting portion 113 opposite to the electrode assembly 12 includes a third surface 1131. Along the direction from the electrode assembly 12 to the end wall 111, the first surface 1120 protrudes from the third surface 1131. The value of the size h2 of the first surface 1120 protruding from the third surface 1131 can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, or any value between two adjacent values, or any value between 0 and 0.1 mm. In some embodiments, the value of h2 can also be 0.1 mm, 0.2 mm, 0.3 mm, or any value between two adjacent values, or any value between 0 and 0.1 mm.

[0277] Optionally, part or all of the connecting portion 113 on the side opposite to the electrode assembly 12 may be flush with the first surface 1120. For example, the side of the connecting portion 113 opposite to the electrode assembly 12 includes a fourth surface, which is flush with the first surface 1120.

[0278] Optionally, referring to FIG5, the side of the connecting portion 113 opposite to the electrode assembly 12 includes a second surface 1130 and a third surface 1131, the second surface 1130 protruding from the first surface 1120, and the first surface 1120 protruding from the third surface 1131.

[0279] In some embodiments described above, the end wall 111 is made of steel. Steps are formed on the inner side of the end wall 111 by stamping, forming the second step surface 1121 of the wall body 112 and the first step surface 1132 of the connecting portion 113. The end wall 111 and the shell 110 are then joined together by side welding. Because the end wall 111 is processed by stamping, a protrusion corresponding to the step is formed on the outer side of the end wall 111. The connecting portion 113 is formed by machining the protrusion. On the one hand, the outer surface of the end wall 111 is relatively flat. When the part connected to the insulating member 13 is a concave-convex surface, the height difference between the concave and convex surfaces can not exceed 0.5 mm under the action of machining. Optionally, the height difference between the concave and convex surfaces can not exceed 0.3 mm under the action of machining. On the other hand, the hardness of the machined part of the end wall 111 is greater than that of the unmachined part. This can improve the structural strength of the shell 11 and improve the impact resistance of the battery cell 10.

[0280] By processing the portion located on the outer periphery of the wall body 112, the distance difference between the side of the connecting portion 113 away from the electrode assembly 12 and the first surface 1120 of the wall body 112 is no greater than 0.5 mm. This effectively improves the problem of insulation failure caused by structural damage to the insulating component 13 located on the outer side of the end due to compression, thereby effectively improving the reliability of the battery device 100. In particular, in the battery cell 10 where the end wall 111 is welded to the housing 110, the end wall 111 has a stepped design. Through machining and other processes, the protrusion on the outer side of the end wall 111 is thinned to form the connecting portion 113, which facilitates the connection of the insulating component 13 and reduces the risk of structural damage to the insulating component 13 caused by compression from external structures, thereby improving the reliability of the battery device 100.

[0281] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery cell, wherein, include: Electrode assembly; The outer casing contains the electrode assembly disposed within it. The outer casing includes a housing and an end wall. The housing has an opening. The end wall includes a wall body and a connecting portion. At least a portion of the connecting portion is circumferentially disposed around the outer periphery of the wall body. A stepped portion is formed on the inner side of the end wall. The stepped portion abuts against the housing. The connecting portion is connected to the housing to close the opening. The tensile strength of the stepped portion at a temperature of 25°C is Rm, which satisfies the condition that 250MPa≤Rm≤2000MPa. Wherein, along the thickness direction of the end wall, the wall body has a first surface opposite to the electrode assembly, and the distance between the side of the connecting portion opposite to the electrode assembly and the first surface is less than or equal to 0.5 mm.

2. The battery cell according to claim 1, wherein, Along the thickness direction of the end wall, the distance between the side of the connection portion away from the electrode assembly and the first surface is less than or equal to 0.3 mm.

3. The battery cell according to claim 1 or 2, wherein, The connecting portion on the side opposite to the electrode assembly includes a second surface that protrudes from the first surface along the direction from the electrode assembly toward the end wall.

4. The battery cell according to any one of claims 1-3, wherein, The connecting portion on the side opposite to the electrode assembly includes a third surface, and the first surface protrudes from the third surface in the direction from the electrode assembly toward the end wall.

5. The battery cell according to any one of claims 1-4, wherein, The connecting portion on the side opposite to the electrode assembly includes a fourth surface, which is flush with the first surface.

6. The battery cell according to claim 1 or 5, wherein, The connecting portion on the side opposite to the electrode assembly includes a second surface and a third surface, the second surface being connected to the third surface. Along the direction of the electrode assembly toward the end wall, the second surface protrudes from the first surface, and the first surface protrudes from the third surface.

7. The battery cell according to any one of claims 1-6, wherein, The connecting part is a ring-shaped structure. The inner periphery of the connecting part is connected to the wall body. Along the direction from the inner periphery of the connecting part to the outer periphery of the connecting part, the distance between the side of the connecting part away from the electrode assembly and the electrode assembly in the thickness direction of the end wall gradually decreases.

8. The battery cell according to any one of claims 1-7, wherein, The hardness of the connecting part is greater than the hardness of the wall body.

9. The battery cell according to any one of claims 1-8, wherein, The connecting part is connected to the housing through the first joint. The stepped portion includes a first stepped surface and a second stepped surface that are connected to each other. The first stepped surface is formed on the side of the connecting portion facing the electrode assembly along the radial direction of the end wall. The second stepped surface is formed on the side of the wall body facing the inner wall surface of the housing along the thickness direction of the end wall. The housing has a first end face facing the connecting portion. The first joint portion is located between the first end face and the first stepped surface.

10. The battery cell according to claim 9, wherein, The first joint is a solder mark formed between the connecting part and the housing.

11. The battery cell according to claim 9 or 10, wherein, The second stepped surface abuts against the inner wall surface of the housing.

12. The battery cell according to any one of claims 1-11, wherein, The battery cell further includes an insulating member that covers at least a portion of the outer peripheral surface of the housing and is connected to the connecting portion on the side opposite to the electrode assembly.

13. The battery cell according to claim 12, wherein, A portion of the insulating element is connected to the first surface.

14. The battery cell according to any one of claims 1-13, wherein, The battery cell also includes an electrode terminal, which is disposed on the first surface and electrically connected to the electrode assembly.

15. The battery cell according to any one of claims 1-14, wherein, There are two end walls, which are opposite each other and connected to the housing respectively along the thickness direction of the end walls.

16. The battery cell according to any one of claims 1-15, wherein, The following conditions must be met: 450MPa≤Rm≤800MPa.

17. The battery cell according to any one of claims 1-16, wherein, The material of the step portion includes one of the following: steel, copper alloy, titanium alloy, and nickel alloy.

18. The battery cell according to claim 17, wherein, The material of the step portion includes stainless steel or carbon steel.

19. The battery cell according to any one of claims 1-18, wherein, The material of the shell is the same as the material of the stepped portion.

20. A battery device, wherein, Includes the battery cell as described in any one of claims 1-19.

21. An electrical device, comprising: Includes the battery cell according to any one of claims 1-19, and / or the battery device according to claim 20, wherein the battery cell is used to provide electrical energy.

22. A method of manufacturing a battery cell, wherein, Includes the following steps: A housing is provided, the housing including a shell and an end wall, at least a portion of the end wall being formed by machining, the end wall including a wall body and a connecting portion at least partially circumferentially disposed around the wall body, and a stepped portion formed on the inner side of the end wall, the stepped portion having a tensile strength Rm at a temperature of 25°C, satisfying 250MPa≤Rm≤2000MPa, the outer side of the wall body having a first surface along the thickness direction of the end wall, and the distance between the outer side of the connecting portion and the first surface being less than or equal to 0.5mm; The electrode assembly is disposed within the housing; The stepped portion abuts against the housing, and the connecting portion is connected to the housing to close the opening of the housing.

23. The method for manufacturing a single battery cell according to claim 22, wherein, The step of providing the housing includes: The wall body, the stepped portion, and the protrusions disposed on the outer periphery of the wall body are formed by stamping. The protrusion is machined on the side of the end wall opposite to the electrode assembly to form the connection portion.

24. The method for manufacturing a single battery cell according to claim 22, wherein, The step of providing the housing includes: The connection portion and the stepped portion are formed by machining on the side of the end wall facing the electrode assembly.

25. The method of manufacturing a battery cell according to claim 22, wherein, The method further includes: An insulating element is covered over at least a portion of the outer periphery of the housing, and the insulating element is connected to the connection portion on the side opposite to the electrode assembly.

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