Battery module, battery pack, and electric device

Abstract

The present application discloses a battery module, a battery pack, and an electric device. The battery module comprises a battery cell stack and a restraining assembly. The battery cell stack comprises multiple battery cells stacked in a first direction. The restraining assembly is circumferentially wound around the battery cell stack in a second direction, so that the restraining assembly can provide a restraining force acting on the battery cell stack in the circumferential direction of the battery cell stack, thereby increasing the restraining force exerted by the restraining assembly on the battery cell stack.

Description

Battery modules, battery packs and electrical equipment

[0001] This application claims priority to Chinese Patent Application No. 202520543013.7, filed on March 25, 2025, entitled “Battery Module, Battery Pack and Electrical Equipment”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, and more specifically, to a battery module, a battery pack, and an electrical device. Background Technology

[0003] During the cyclic charging and discharging process, the cells within the battery pack transition between low and high charge levels. Consequently, the internal chemical reactions within the cells cause them to expand or contract. The simultaneous expansion of multiple cells in the battery pack generates significant expansion forces. To ensure the interface requirements of the cells during charge-discharge cycles, an anti-expansion structure is needed to resist these expansion forces and reduce the degree of cell expansion deformation.

[0004] Currently, the anti-expansion structure of battery packs uses a structure in which a metal tension plate is connected to the end plate of the battery pack. This structure has relatively low restraint force and cannot meet the anti-expansion requirements of battery packs with large expansion forces. Summary of the Invention

[0005] The purpose of this application is to provide a battery module, battery pack, and electrical equipment that solves the problem of low restraint force in the anti-expansion structure of the battery pack in the related art.

[0006] In a first aspect, this application provides a battery module, including:

[0007] A battery cell stack includes a plurality of battery cells stacked along a first direction, wherein each battery cell has a tab on one side along a second direction;

[0008] A restraint assembly is circumferentially wound around the cell stack along the second direction, where the first and second directions intersect.

[0009] In some embodiments, the first direction is the thickness direction of the battery cell, and the second direction is perpendicular to the first direction.

[0010] In some embodiments, the restraint assembly forms a first orthographic projection on the surface of the cell stack, and the surface of the cell stack covers the first orthographic projection.

[0011] In some embodiments, the restraint assembly includes a plurality of restraint wires, which are spaced apart.

[0012] Alternatively, multiple restraint wires may be arranged adjacent to each other;

[0013] Alternatively, at least some of the multiple restraint wires may be stacked together.

[0014] In some embodiments, the restraint wire is a carbon fiber wire and / or a metal wire.

[0015] In some embodiments, the cross-sectional area of ​​the restraint assembly in the first direction satisfies: S1≥F / (2×Rm);

[0016] Wherein, S1 is the cross-sectional area of ​​the restraint assembly in the first direction, F is the preset restraint force acting on the battery cell stack, and Rm is the tensile strength of the restraint wire in the first direction.

[0017] In some embodiments, the cell stack further includes at least one end plate, which is stacked on the cell along the first direction, and the at least one end plate is located outside the outermost cell among the plurality of cells.

[0018] In some embodiments, the end plate has an arc surface on the side opposite to the battery cell.

[0019] In some embodiments, the end plate includes an abutting portion and a winding portion, the abutting portion abutting against the battery cell, the two ends of the winding portion extending in the direction of extension being respectively connected to the abutting portion, and a cavity being formed between the winding portion and the abutting portion.

[0020] In some embodiments, the end plate further includes a support portion located in the cavity and connected to the abutment portion and the winding portion.

[0021] In some embodiments, the end plate forms a second orthographic projection on the cell along the first direction, and the second orthographic projection is covered by the cell.

[0022] In some embodiments, the second orthographic projection coincides with the battery cell.

[0023] In some embodiments, at least two end plates are located at both ends of the cell stack along the first direction, a plurality of cells are electrically connected, a plurality of cells are electrically connected to at least two end plates, and at least two end plates respectively form the positive terminal and the negative terminal of the cell stack.

[0024] In some embodiments, the cell stack further includes an electrical connector that connects the plurality of cells to the two end plates.

[0025] In some embodiments, the electrical connector includes a plurality of electrical connection portions that connect to the tabs of adjacent cells and connect the end plate to the adjacent cells.

[0026] In some embodiments, positive and negative connection portions are respectively provided on opposite sides of the two end plates, and the positive and negative connection portions are electrically connected to the corresponding end plates.

[0027] In some embodiments, the battery module further includes a positive electrode connection portion and a negative electrode connection portion, both of which are electrically connected to the battery cell. The positive electrode connection portion and the negative electrode connection portion respectively constitute the positive electrode connection end and the negative electrode connection end of the battery cell stack.

[0028] In some embodiments, the positive electrode connection is electrically connected to one of the outermost cells of the plurality of cells, and the negative electrode connection is electrically connected to another of the outermost cells of the plurality of cells.

[0029] In some embodiments, at least a portion of the end plate is a thermally expandable structure, the end plate being used to expand under heat to compress the battery cell.

[0030] In some embodiments, the cell stack further includes at least one thermal expansion member, which is stacked on the cell along the first direction, and the thermal expansion member is used to expand under heat to compress the cell.

[0031] In some embodiments, at least two of the thermal expansion elements are adjacent along the first direction and have different coefficients of thermal expansion.

[0032] In some embodiments, among the plurality of thermal expansion elements stacked sequentially along a first direction, the coefficient of thermal expansion of any one of the thermal expansion elements is higher or lower than the coefficient of thermal expansion of the thermal expansion elements on opposite sides.

[0033] In some embodiments, at least one of the thermal expansion elements is disposed between adjacent battery cells.

[0034] In some embodiments, at least one of the thermal expansion elements is disposed between the end plate and the adjacent battery cell.

[0035] Secondly, based on the battery module described above, this application also provides a battery pack, including a tray and the battery module described above, wherein the tray has a battery cavity and the battery module is disposed in the battery cavity.

[0036] In some embodiments, along the first direction, the battery cavity has two opposing abutting inner walls, and the opposite sides of the restraint assembly abut against the two abutting inner walls respectively.

[0037] Thirdly, based on the battery module or battery pack described above, this application also provides an electrical device, including the battery module or battery pack described above.

[0038] This application provides a battery module in which multiple battery cells are stacked along a first direction, resulting in a compact overall structure of the cell stack. A restraining component is wound around the cell stack circumferentially, providing restraining force in all circumferential directions, thus increasing the restraining force exerted by the restraining component on the cell stack. This ensures that even with significant expansion forces within the cell stack, the restraining component maintains the interface requirements of the cells. Simultaneously, the restraining component is wound circumferentially along a second direction, preventing interference between the restraining component and the cell tabs. This ensures that the tabs do not affect the restraining force of the restraining component, and the restraining component does not obstruct the tabs when wound around the cell stack, allowing for easy connection of the tabs to other electrical connection components.

[0039] In the battery pack provided in this application, the tray can be used to support and install the battery modules, and the tray can also protect the battery modules to a certain extent, so as to make the structure of the battery pack more stable.

[0040] The electrical equipment provided in this application, including the battery module or battery pack mentioned above, makes the electrical equipment safer and more reliable during operation. Attached Figure Description

[0041] Figure 1 is a schematic diagram of the battery module provided in an embodiment of this application;

[0042] Figure 2 is a schematic diagram of the restraint assembly of the battery module provided in an embodiment of this application;

[0043] Figure 3 is a schematic diagram of the restraint wire of the battery module provided in the embodiment of this application;

[0044] Figure 4 is a schematic diagram of the thermal expansion component of the battery module provided in the embodiment of this application;

[0045] Figure 5 is a schematic diagram showing that the battery module provided in the embodiment of this application has three thermal expansion components;

[0046] Figure 6 is a schematic diagram of the electrical connections of the battery module provided in an embodiment of this application;

[0047] Figure 7 is a magnified view of area A in Figure 6;

[0048] Figure 8 is a schematic diagram of the positive electrode connection portion of the battery module provided in an embodiment of this application;

[0049] Figure 9 is a magnified view of area B in Figure 8;

[0050] Figure 10 is a schematic diagram of the battery pack provided in an embodiment of this application;

[0051] Figure 11 is a schematic diagram of the electrical equipment provided in the embodiment of this application.

[0052] Reference numerals: 10-Battery module; 20-Battery pack; 30-Electrical device; 100-Cell stack; 110-Cell; 111-Taper; 120-End plate; 121-Abutting part; 122-Winding part; 123-Supporting part; 124-Cavity; 130-Electrical connector; 131-Electrical connector; 140-Thermal expansion part; 150-Positive electrode connection part; 160-Negative electrode connection part; 200-Constraint assembly; 210-Constraint wire; 220-First restraint part; 230-Second restraint part; 300-Tray; 310-Battery cavity; 311-Abutting inner wall. Detailed Implementation

[0053] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0054] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0055] During the cyclic charging and discharging process, the cells within the battery pack transition between low and high charge levels. Consequently, the internal chemical reactions within the cells cause them to expand or contract. The simultaneous expansion of multiple cells in the battery pack generates significant expansion forces. To ensure the interface requirements of the cells during charge-discharge cycles, an anti-expansion structure is needed to resist these expansion forces and reduce the degree of cell expansion deformation.

[0056] Currently, the anti-expansion structure of battery packs adopts a structure in which a metal pull plate is threadedly connected to the end plate of the battery pack. The restraining force of this structure is entirely provided by the connection between the pull plate and the end plate. However, the threaded connection between the pull plate and the end plate cannot provide a large restraining force, resulting in a small restraining force in this structure, which cannot meet the anti-expansion requirements of battery packs with large expansion forces.

[0057] To overcome the deficiencies in related technologies, this application employs a battery module in which multiple battery cells are stacked along a first direction, resulting in a compact overall structure. A restraining component is wound around the battery cell stack circumferentially, providing restraining force in all circumferential directions, thus increasing the restraining force exerted by the component on the stack. This ensures that even with significant expansion forces within the stack, the restraining component can still guarantee the interface requirements of the cells. Furthermore, the restraining component is a deformable structure, allowing it to be wound around the stack. This winding ensures more thorough and tighter contact between the component and the stack, further increasing the restraining force and making the battery module more stable and safer during charging and discharging. Meanwhile, the restraint assembly is circumferentially wound around the cell stack along the second direction, so that the restraint assembly and the cell tabs will not interfere with each other. In this way, the tabs will not affect the restraint force of the restraint assembly, and the restraint assembly will not block the tabs when it is wound around the cell stack, so that the tabs can be easily connected to other electrical connection components.

[0058] In the battery pack proposed in this application, the tray can be used to support and install the battery modules, and the tray can also protect the battery modules to a certain extent, so as to make the structure of the battery pack more stable.

[0059] The electrical equipment proposed in this application, including the battery module or battery pack mentioned above, makes the electrical equipment safer and more reliable during operation.

[0060] The contents of this application will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can have a clearer and more detailed understanding of the contents of this application.

[0061] This application proposes a battery module, as shown in Figures 1 and 3, including a cell stack 100 and a restraint assembly 200. This battery module 10 can be applied to a battery pack or electrical device.

[0062] The cell stack 100 includes multiple cells 110, which can be stacked along a first direction, i.e., the X direction in Figure 1. This allows the multiple cells 110 to be arranged more centrally, making the structure of the cell stack 100 more compact. The multiple cells 110 increase the capacity of the cell stack 100, thereby increasing the capacity of the battery module 10 of this application.

[0063] The battery cell 110 has a tab 111 on one side. The tab 111 is a component that connects the battery cell 110 to an external electrical connection component. The tab 111 may include a positive tab and a negative tab, which can constitute the positive and negative terminals of the battery cell 110. Specifically, one end of the tab 111 extends into the interior of the battery cell 110, and the other end of the tab 111 extends into the exterior of the battery cell 110.

[0064] In this configuration, a tab 111 is provided on one side of the battery cell 110 along a second direction, which intersects with the first direction. The second direction is the Y direction in Figure 1. In this way, the battery cell 110 and the tab 111 can be distributed along the second direction, so that the tab 111 is located at the end of the battery cell 110. Correspondingly, when multiple battery cells 110 are stacked along the first direction, the tab 111 will not affect the stacking of multiple battery cells 110, making the structure of the battery cell stack 100 more compact.

[0065] The restraint component 200 is circumferentially wound around the cell stack 100 along the second direction, so that the restraint component 200 can be pressed onto the cell stack 100. The restraint component 200 can form a restraining force acting towards the cell stack 100. This restraining force can, to a certain extent, counteract the expansion force generated by the cell 110 during charging and discharging, so that the part of the cell stack 100 wound by the restraint component 200 is restricted within the restraint component 200, avoiding excessive deformation and expansion of the cell 110 in the cell stack 100, ensuring the interface requirements of the cell 110 during charging and discharging, and making the battery module 10 of this application more stable and reliable.

[0066] The restraint component 200 is wound around the cell stack 100, so that the restraint component 200 can provide restraint force on the cell stack 100 in the circumferential direction, thereby making the restraint force exerted by the restraint component 200 on the cell stack 100 greater. In this way, even if the expansion force of the cell stack 100 is large, the restraint component 200 can still ensure the interface requirements of the cells 110 in the cell stack 100.

[0067] Furthermore, since the restraint component 200 can be wound around the cell stack 100, the restraint component 200 is a deformable structural component. The restraint component 200 has a more sufficient and tighter contact with the cell stack 100, thereby making the restraint force of the restraint component 200 on the cell stack 100 greater, making the battery module 10 more stable and safer during charging and discharging.

[0068] Specifically, the circumferential direction of the second direction is perpendicular to the second direction in its plane, and the circumferential direction of the second direction is rotated around the second direction. By winding the restraint assembly 200 around the cell stack 100 along the circumferential direction of the second direction, the restraint assembly 200 can avoid the tab 111 on one side of the cell 110. In this way, when the restraint assembly 200 is set, the tab 111 will not interfere with the restraint assembly 200, and the restraint assembly 200 can fully contact and cooperate with the surface of the cell 110 in the circumferential direction of the second direction, so that the restraint force of the restraint assembly 200 on the cell stack 100 is more sufficient, making the battery module 10 more stable and safer during charging and discharging.

[0069] Specifically, the restraint assembly 200 forms a first orthographic projection on the surface of the cell stack 100 in the direction toward the cell stack 100. The first orthographic projection is the projection area formed by the portion of the restraint assembly 200 and the cell stack 100 opposite to each other. Correspondingly, the first orthographic projection can be distributed on the surface of each cell 110, with the first orthographic projection located on one side of the surface of the cell 110 and the tab 111 located on the other side of the surface of the cell 110. In this way, the first orthographic projection of the restraint assembly 200 and the tab 111 are located on different sides of the surface of the cell 110, so that the restraint assembly 200 and the tab 111 of the cell 110 have a certain distance between them, and the restraint assembly 200 and the tab 111 will not interfere with each other.

[0070] Specifically, when the restraint assembly 200 is wound around the cell stack 100, it does not obstruct or contact the tab 111, allowing the tab 111 to be exposed on the surface of the cell 110. The tab 111 can be easily connected to other electrical connection components, enabling the cell 110 to be charged or discharged to the outside. Correspondingly, the tab 111 does not affect the winding path of the restraint assembly 200, allowing the restraint assembly 200 to be fully wound around one side of the cell 110, resulting in more sufficient contact between the restraint assembly 200 and the cell stack 100. This leads to a greater restraining force exerted by the restraint assembly 200 on the cell stack 100, making the structure of the cell stack 100 more stable during charging and discharging.

[0071] In addition, when preparing the battery module 10 of this application, it is necessary to wind the restraint component 200 around the cell stack 100 so that the tab 111 will not interfere with the restraint component 200 being wound around the cell stack 100, thereby making it more convenient for the restraint component 200 to be wound around the cell stack 100.

[0072] In some embodiments, the first direction can be set as the thickness direction of the cell 110, wherein the thickness direction of the cell 110 is the X direction in Figure 1, and the cell 110 also has a length direction and a width direction. Multiple cells 110 can also be electrically connected, specifically in series, thus increasing the capacity of the battery module 10 of this application. It should be understood that the cell 110 can have a structure similar to a thin plate, making the length and width dimensions of the cell 110 larger than its thickness dimension. The ratio of the length, width, and thickness dimensions of the cell stack 100 formed by stacking multiple cells 110 along the thickness direction is smaller. This avoids the cell stack 100 being too large in a single direction, effectively reducing the ratio of the length, width, and thickness of the cell stack 100, thus making the structure of the cell stack 100 compact.

[0073] The second direction is perpendicular to the first direction, so that the direction from the tab 111 to the cell 110 is perpendicular to the first direction, that is, the direction from the tab 111 to the cell 110 is perpendicular to the thickness direction of the cell 110. Accordingly, the tab 111 is located on the surface of the cell 110 facing the surface perpendicular to the first direction.

[0074] It should be understood that among the various surfaces of the battery cell 110, the surface facing the same direction as the first direction is the large surface of the battery cell 110, and the area of ​​the large surface of the battery cell 110 is relatively larger than the area of ​​the other side surfaces of the battery cell 110. During the charging and discharging process, the expansion force of the battery cell 110 is mainly along the first direction, making the expansion tendency of the large surface the greatest. That is, the expansion of the battery cell 110 is mainly manifested in the expansion of the large surfaces on opposite sides of the battery cell 110 in opposite directions. Correspondingly, the overall expansion trend of the battery cell stack 100 is mainly formed along the positive and negative directions of the first direction.

[0075] In this application, the direction of the restraining force generated by the restraining component 200 on the cell stack 100 includes a first direction, so that the restraining force of the restraining component 200 on the cell stack 100 can suppress the tendency of the cell stack 100 to expand in both directions along the first direction, thereby suppressing the main expansion trend of the cell stack 100, so that the cell stack 100 can have better structural stability in the first direction.

[0076] Furthermore, it should be understood that, since the restraint assembly 200 is wound around the cell stack 100, the restraint assembly 200 can also exert a force on the cell stack 100 in a direction simultaneously perpendicular to the first direction and the second direction. Specifically, the restraint assembly 200 can also be pressed onto the surface of the cell stack 100 that is perpendicular to the first direction and does not have tabs 111, thereby allowing the restraint assembly 200 to suppress the expansion deformation of the cell stack 100 in the direction perpendicular to the first direction.

[0077] In some embodiments, referring to FIG2, the restraint assembly 200 of this application may include a first restraint portion 220 and a second restraint portion 230. The first restraint portion 220 is connected to the second restraint portion 230, and the second restraint portion 230 is opposite to both ends of the cell stack 100 in a first direction. The first restraint portion 220 is disposed along the first direction such that the surface of the first restraint portion 220 faces the outer wall perpendicular to the first direction. The second restraint portion 230 may be pressed onto both ends of the cell stack 100 in the first direction, thereby suppressing the expansion deformation of the cell stack 100 in both directions of the first direction. Since the second restraint portion 230 is connected to the first restraint portion 220, the first restraint portion 220 can also suppress the expansion deformation of the cell stack 100 in both directions of the first direction. Furthermore, the first restraint portion 220 can also suppress the expansion deformation of the cell stack 100 in directions perpendicular to both the first and second directions.

[0078] In some embodiments, referring to FIG1, the surface of the cell stack 100 of this application covers the first orthographic projection, such that the entire first orthographic projection is located on the surface of the cell stack 100. This makes the entire restraint component 200 wrapped around the surface of the cell stack 100, thereby saving the material used for the restraint component 200 and reducing the manufacturing cost of the battery module 10 of this application.

[0079] In some embodiments, referring to FIG3, the restraint assembly 200 of this application may include multiple restraint wires 210, each of which is a long, thin, filamentous structure. All multiple restraint wires 210 are wound around the cell stack 100. Each of the multiple restraint wires 210 can generate a restraining force on the cell stack 100, and the restraining forces generated by the multiple restraint wires 210 on the cell stack 100 can be superimposed to form the restraining force generated by the restraint assembly 200 on the cell stack 100.

[0080] By setting the restraint assembly 200 to include multiple restraint wires 210, such that the diameter of each restraint wire 210 is relatively small, the process of winding each restraint wire 210 around the cell stack 100 can be relatively simpler, thereby reducing the manufacturing process cost of the battery module 10 of this application.

[0081] Multiple restraint wires 210 can be wound at intervals around the cell stack 100. Correspondingly, the number of restraint wires 210 is relatively smaller, and the material of the restraint wires 210 can be a material with higher tensile strength. This can reduce the amount of restraint wires 210 used, thereby reducing the cost of the battery module 10 of this application.

[0082] At least some of the multiple restraint wires 210 can be stacked, resulting in a relatively larger number of restraint wires 210. The restraint wires 210 can be made of materials with higher tensile strength, which can enhance the restraint force of the restraint assembly 200. Alternatively, the restraint wires 210 can be made of materials with relatively lower tensile strength to reduce the cost of the battery module 10 of this application.

[0083] Specifically, the tensile strength and quantity of the restraint wires 210 can be flexibly determined according to the expansion force of the battery cell 110, so as to ensure that the restraint force of the restraint assembly 200 on the battery cell stack 100 can fully suppress the expansion trend of the battery cell 110 while keeping costs lower.

[0084] Multiple restraint wires 210 can also be arranged adjacently, that is, multiple restraint wires 210 can be arranged sequentially along multiple directions, and adjacent restraint wires 210 can be in contact or not in contact.

[0085] In some embodiments, the restraint wire 210 of this application has a cross-section in the first direction. Specifically, when the restraint wire 210 is cylindrical, the cross-section in the first direction is the cross-section along the axial direction of the restraint wire 210, and the cross-section in the first direction is circular. Correspondingly, the area of ​​the cross-section of the restraint wire 210 in the first direction determines the thickness of the restraint wire 210. The larger the area of ​​the cross-section of the restraint wire 210 in the first direction, the thicker the restraint wire 210, and the greater the restraining force exerted by the restraint wire 210 on the cell stack 100. The smaller the area of ​​the cross-section of the restraint wire 210 in the first direction, the thinner the restraint wire 210, and the smaller the restraining force exerted by the restraint wire 210 on the cell stack 100. The sum of the cross-sectional areas of multiple restraint wires 210 in the first direction constitutes the cross-sectional area of ​​the restraint assembly 200 in the first direction.

[0086] The cross-section of the restraint assembly 200 in the first direction satisfies the following formula:

[0087] S1≥F / (2×Rm).

[0088] Wherein, S1 is the cross-sectional area of ​​the restraint component 200 in the first direction, and F is the preset restraint force acting on the cell stack 100. When the restraint force of the restraint component 200 acting on the cell stack 100 is greater than or equal to the preset restraint force, the expansion degree of the cell 110 is less than the preset expansion degree, so that the cell 110 can be charged and discharged safely and reliably. If the restraint force of the restraint component 200 acting on the cell stack 100 is less than F, then the restraint component 200 cannot sufficiently suppress the expansion trend of the cell 110, and the expansion degree of the cell 110 is greater than the preset degree, then the safety risk of the cell 110 during the charging and discharging process is greater. Rm is the tensile strength of the restraint wire 210 in the first direction. Since the restraint assembly 200 is wound around the cell stack 100, the portions of the restraint assembly 200 located on opposite sides of the cell stack 100 can provide restraint force acting on the cell stack 100. Therefore, 2 in the formula means that the portions of the restraint assembly 200 located on opposite sides of the cell stack 100 can provide restraint force acting on the cell stack 100.

[0089] Specifically, Rm is determined by the material of the restraint wire 210, and the value of S1 obtained by the above formula is the minimum cross-sectional area required by the restraint assembly 200 in the first direction when the battery module 10 of this application is safely and reliably charged and discharged. Specifically, the larger the cross-sectional area of ​​the restraint assembly 200 in the first direction, the greater the restraining force it can provide. In addition, the minimum diameter of a single restraint wire 210 can be obtained according to the number of restraint wires 210 included in the restraint assembly 200.

[0090] Furthermore, it should be understood that F in the above formula can also be obtained by the preset pressure acting on the end of the cell 110 along the first direction, and the area of ​​the end of the cell 110 in the first direction. The preset pressure is the minimum pressure acting on the cell 110 in the first direction required for the battery module 10 to operate safely and reliably. Specifically, F = P * S², where P is the preset pressure acting on the end of the cell 110 in the first direction, and S² is the area of ​​the end of the cell 110 in the first direction.

[0091] For example, when Rm is 2000MPa and F is 10MPa, the area ratio of S1 to S2 is 1:400. Therefore, the ratio of the cross-sectional area of ​​the restraint assembly 200 in the first direction to the area of ​​the end of the cell 110 in the first direction must be at least 1:400 to ensure that the restraint force provided by the restraint assembly 200 can meet the interface requirements of the cell 110 during the charging and discharging process.

[0092] It should also be understood that the aforementioned F can be measured experimentally using other testing equipment. Specifically, pressure can be applied to both opposite sides of the cell stack 100 using a pressurizing device, and the cell stack 100 can be charged and discharged. The pressure applied to both opposite sides of the cell stack 100 by the pressurizing device can be adjusted. By applying different magnitudes of pressure to both opposite sides of the cell stack 100 and measuring the degree of expansion of the cell stack 100 under different pressure magnitudes, the minimum pressure required for the cell stack 100 to maintain a preset expansion range can be determined, thereby obtaining the minimum restraint force F required for the cell stack 100 to maintain structural stability.

[0093] In some embodiments, referring to Figures 1 and 2, the cell stack 100 of this application may further include at least one end plate 120. Specifically, there are two end plates 120, both of which are stacked on the cell 110 along a first direction, and the two end plates 120 are located on opposite sides of the two outermost cells 110. The two end plates 120 can clamp the multiple cells 110, thus preventing the ends of the cells 110 from being exposed in the first direction, and serving the purpose of protecting and limiting the cells 110.

[0094] It should be understood that, because the restraint wire 210 of the restraint assembly 200 is relatively thin, if the restraint wire 210 is directly wound around the end of the battery cell 110 along the first direction, it will create a large pressure on the end of the battery cell 110, which could easily damage the battery cell 110. Therefore, the restraint assembly 200 is also wound around the end plate 120. The end plate 120 can separate the restraint assembly 200 from the end of the battery cell 110 along the first direction, preventing the restraint assembly 200 from being directly pressed onto the end of the battery cell 110 along the first direction, so as to avoid excessive pressure on the end of the battery cell 110 and damage to the battery cell 110.

[0095] When there is only one end plate 120, the end plate 120 can be stacked on any side of the cell stack 100 along the first direction.

[0096] In some embodiments, referring to Figures 1 and 2, the surface of the end plate 120 facing away from the cell 110 can be configured to have an arc surface, and the restraint assembly 200, when wound around the end plate 120, contacts the side of the end plate 120 facing away from the cell 110. By configuring the surface of the end plate 120 facing away from the cell 110 as an arc surface, the restraint force exerted by the restraint assembly 200 on the end plate 120 can be evenly diffused, making the restraint force distribution of the restraint assembly 200 on the end plate 120 more uniform, thereby making the restraint force exerted by the restraint assembly 200 on the cell stack 100 more uniformly distributed. In this way, the restraint assembly 200 can better provide the cell stack 100 with a restraint force that can suppress the expansion deformation of the cell stack 100.

[0097] In addition, the surface of the end plate 120 facing away from the cell 110 can be configured to have an arc surface, which can also avoid sharp structures on the side of the end plate 120 facing away from the cell 110, thereby fully converting the restraining force provided by the restraining wire 210 into stress along the axial direction of the restraining wire 210, thereby avoiding the restraining wire 210 from being subjected to large shear stress and reducing the risk of the restraining wire 210 breaking.

[0098] Specifically, the side surface of the end plate 120 facing away from the battery cell 110 can be configured to have a continuous arc surface, that is, the side surface of the end plate 120 facing away from the battery cell 110 is a circular arc segment, so that when the restraint wire 210 is wound on the end plate 120, it can fully contact the side surface of the end plate 120 facing away from the battery cell 110.

[0099] The surface of the end plate 120 facing away from the cell 110 can also be configured as a multi-segment arc surface, which can also avoid sharp structures on the side of the end plate 120 facing away from the cell 110.

[0100] In some embodiments, referring to Figures 1, 4, and 5, to allow the surface of the end plate 120 facing away from the battery cell 110 to be configured as an arc surface, the end plate 120 includes an abutment portion 121 and a winding portion 122. The abutment portion 121 abuts against the end of the battery cell 110 in a first direction. The winding portion 122 is connected to the abutment portion 121, and the winding portion 122 is located on the side of the abutment portion 121 facing away from the battery cell 110; correspondingly, the surface of the winding portion 122 facing away from the abutment portion 121 has an arc surface structure.

[0101] Specifically, the side of the abutment portion 121 facing the battery cell 110 is flat, allowing the abutment portion 121 to fully contact the end of the battery cell 110 in the first direction, thus making the restraining force exerted by the abutment portion 121 on the battery cell 110 more uniform. The restraint assembly 200 is wound around the surface of the winding portion 122 facing away from the abutment portion 121. The connection between the winding portion 122 and the abutment portion 121 can be set as an arc transition, which can avoid sharp structures at the connection between the winding portion 122 and the abutment portion 121. Correspondingly, the shear stress on the restraint wire 210 at the connection between the winding portion 122 and the abutment portion 121 can be reduced, further reducing the risk of the restraint wire 210 breaking.

[0102] In some embodiments, referring to Figures 1, 4, and 5, the two ends of the winding portion 122 in this application can be connected to the two ends of the abutment portion 121 in its extending direction, respectively, and a cavity 124 is formed between the winding portion 122 and the abutment portion 121. Specifically, the middle section of the winding portion 122 in its extending direction has a gap with the abutment portion 121 to form the cavity 124. This reduces the amount of material used in the preparation of the end plate 120, thereby reducing the weight of the end plate 120 and lowering its manufacturing cost.

[0103] The end plate 120 of this application also includes a support portion 123, which is located in the cavity 124 between the abutment portion 121 and the winding portion 122. The two ends of the support portion 123 are respectively connected to the abutment portion 121 and the winding portion 122. The support portion 123 can support the winding portion 122 and prevent the winding portion 122 from deforming towards the abutment portion 121 after being restrained by the restraining force of the restraining component 200, thereby enabling the end plate 120 as a whole to maintain better structural strength.

[0104] Specifically, one end of the support portion 123 can be connected to the middle portion of the abutment portion 121, and the other end of the support portion 123 can be connected to the middle portion of the winding portion 122, thereby making the supporting force of the support portion 123 on the winding portion 122 more balanced. The number of support portions 123 can also be multiple, with each support portion 123 located in the gap between the abutment portion 121 and the winding portion 122, and both ends of each support portion 123 connected to the abutment portion 121 and the winding portion 122 respectively. All the support portions 123 can support the winding portion 122, thereby further preventing the winding portion 122 from deforming towards the abutment portion 121 after being restrained by the restraining force of the restraining component 200, resulting in better overall structural strength of the end plate 120.

[0105] One end of each of the multiple support portions 123 can be connected to the middle part of the abutment portion 121, and the other end of each of the multiple support portions 123 can be arranged at intervals along the circumference of the winding portion 122. In this way, the multiple support portions 123 are arranged radially along the arc surface of the winding portion 122 on the side opposite to the abutment portion 121, so that the winding portion 122 is supported by the support portions 123 more evenly.

[0106] In some embodiments, referring to FIG1, the end plate 120 of this application forms a second orthographic projection on the cell 110 along a first direction. The second orthographic projection is covered by the cell 110, that is, the second orthographic projection can be located inside the end of the cell 110 in the first direction. In this way, the side of the end plate 120 facing the cell 110 is in contact with the cell 110. Correspondingly, the cell 110 can be supported in the opposite direction on the side of the end plate 120 facing the cell 110, making the structure of the end plate 120 more stable. In addition, the material used in the end plate 120 can be reduced, thereby reducing the manufacturing cost of the battery module 10 of this application.

[0107] In some embodiments, referring to FIG1, the end plate 120 forms a second orthographic projection on the cell 110 along the first direction, which can coincide with the cell 110. In this way, the second orthographic projection can just cover the end of the cell 110 along the first direction, so that the end plate 120 can fully cover the cell 110 to avoid the end of the cell 110 being exposed in the first direction. The end plate 120 can fully protect the cell 110.

[0108] Furthermore, the overlap between the end plate 120 and the end of the battery cell 110 in the first direction allows for a continuous transition at the connection between the end plate 120 and the adjacent battery cell 110, preventing sharp structures from appearing at the connection. This reduces the shear stress on the restraint wire 210 at the connection between the end plate 120 and the adjacent battery cell 110 when the restraint wire 210 passes through it, thereby lowering the risk of breakage.

[0109] In addition, in other embodiments, the area of ​​the second orthographic projection formed by the end plate 120 on the cell 110 along the first direction can be set to be smaller than the area of ​​the end of the cell 110 in the first direction. This can save the material used in the end plate 120, thereby reducing the cost of the battery module 10 of this application.

[0110] In some embodiments, referring to FIG1, after the multiple cells 110 of this application are connected in series, the cell stack 100 also needs to be provided with a positive terminal and a negative terminal, so that the multiple cells 110 of the cell stack 100 can be connected to an external electrical connection structure to enable the cells 110 to be charged and discharged. When the number of end plates 120 in this application is two, both end plates 120 can be electrically connected to the cells 110, and the two end plates 120 can serve as the positive terminal and the negative terminal of the cell stack 100, respectively. The external electrical connection structure can be electrically connected to the two end plates 120 to realize the electrical connection between the cell stack 100 and the external electrical connection structure.

[0111] By connecting the end plate 120 to the external electrical connection structure, it is not necessary to set up additional components for electrically connecting the cell 110 to the external electrical connection structure, thereby reducing the number of components in the battery module 10 of this application, simplifying the structure of the battery module 10, and reducing the cost of the battery module 10.

[0112] Specifically, in order to make the end plate 120 conductive, the end plate 120 is made of metal, which also gives the end plate 120 better structural strength. When the restraining force of the restraining component 200 is applied to the end plate 120, the end plate 120 can maintain structural stability and reliability.

[0113] In other embodiments, when there are two or more end plates 120, two of the end plates 120 can be electrically connected to the cell stack 100, while the other end plates 120 can be configured not to be electrically connected to the cell stack 100. Alternatively, all end plates 120 can be electrically connected to the cell stack 100, with two end plates 120 serving as the positive and negative terminals of the cell stack 100, respectively.

[0114] In some embodiments, referring to Figures 6 and 7, in order to make the multiple battery cells 110 electrically connectable, the battery cell stack 100 of this application may also be provided with an electrical connector 130. The electrical connector 130 is connected to the multiple battery cells 110 and two end plates 120. The multiple battery cells 110 can be electrically connected through the electrical connector 130, and the end plates 120 can also be electrically connected to the battery cells 110 through the electrical connector 130.

[0115] Specifically, the electrical connector 130 can connect the tabs 111 of multiple battery cells 110 and connect the tabs 111 of the battery cells 110 to the end plate 120, thereby realizing the electrical connection between the multiple battery cells 110 and the end plate 120.

[0116] In some embodiments, referring to Figures 6 and 7, the electrical connector 130 may include a plurality of electrical connection portions 131, which can connect to the tabs 111 of adjacent battery cells 110 and connect the end plate 120 to adjacent battery cells 110. Specifically, when the number of battery cells 110 is at least three, the three battery cells 110 can be electrically connected to adjacent battery cells 110 through two electrical connection portions 131. The two end plates 120 are respectively electrically connected to adjacent battery cells 110 through two electrical connection portions 131.

[0117] The electrical connection portion 131 can be connected to the tab 111 of the adjacent battery cell 110 by welding, so as to ensure a reliable connection between the electrical connection portion 131 and the tab 111 of the battery cell 110. The electrical connection portion 131 can also be connected to the end plate 120 and the tab 111 of the adjacent battery cell 110 by welding, so as to ensure a reliable connection between the electrical connection portion 131 and the end plate 120 and the tab 111 of the battery cell 110.

[0118] It should be noted that the electrical connection portion 131 and the electrode tab 111 are located on the same side of the battery cell 110, so that the electrical connection portion 131 and the electrode tab 111 can be arranged close to each other, making it convenient to connect the electrical connection portion 131 and the electrode tab 111. In addition, the electrical connection portion 131 and the first orthographic projection can be located on different sides of the surface of the battery cell 110, thereby avoiding mutual interference between the electrical connection portion 131 and the restraint assembly 200.

[0119] In some embodiments, referring to Figures 6 and 7, in order for the two end plates 120 to constitute the positive and negative connection terminals of the cell stack 100, one of the end plates 120 may be electrically connected to the electrical connection portion 131 corresponding to the adjacent cell 110. This allows the end plate 120 to be electrically connected to the adjacent cell 110, thereby enabling the end plate 120 to serve as the positive connection terminal of the cell stack 100. The other end plate 120 may be electrically connected to the electrical connection portion 131 corresponding to the adjacent cell 110. This allows the end plate 120 to be electrically connected to the adjacent cell 110, thereby enabling the end plate 120 to serve as the negative connection terminal of the cell stack 100.

[0120] Referring to Figures 1 and 2, the cell stack 100 further includes a positive electrode connection portion 150 and a negative electrode connection portion 160. The positive electrode connection portion 150 is electrically connected to one of the two end plates 120. The other end plate 120 is provided with the negative electrode connection portion 160, and the negative electrode connection portion 160 is electrically connected to the end plate 120. The positive electrode connection portion 150 and the negative electrode connection portion 160 are located on opposite sides of the two end plates 120. The positive electrode connection portion 150 and the negative electrode connection portion 160 can be connected to an external electrical connection structure, so that the cell stack 100 can be connected to an external electrical connection structure through the positive electrode connection portion 150 and the negative electrode connection portion 160.

[0121] The positive electrode connection portion 150 can be integrally formed with the corresponding end plate 120 to ensure a stable and reliable connection between the positive electrode connection portion 150 and the end plate 120. Specifically, the end plate 120 can be integrally formed with the positive electrode connection portion 150 during the fabrication process, thus eliminating the need for additional assembly of the positive electrode connection portion 150 and the end plate 120.

[0122] The negative electrode connection portion 160 can be integrally formed with the corresponding end plate 120 to ensure a stable and reliable connection between the negative electrode connection portion 160 and the end plate 120. Specifically, the end plate 120 and the negative electrode connection portion 160 can be integrally formed during the fabrication of the end plate 120, thus eliminating the need for additional assembly of the negative electrode connection portion 160 and the end plate 120.

[0123] In some embodiments, referring to Figures 8 to 9, the positive electrode connection portion 150 and the negative electrode connection portion 160 of the cell stack 100 of this application may also be configured to be electrically connected to the cell 110. The positive electrode connection portion 150 may serve as the positive electrode connection end of the cell stack 100, and the negative electrode connection portion 160 may serve as the negative electrode connection end of the cell stack 100.

[0124] In some embodiments, referring to Figures 8 and 9, the positive electrode connection 150 may be configured to connect to one of the plurality of electrical connection portions 131, thereby enabling the positive electrode connection 150 to be electrically connected to the battery cell 110 corresponding to that electrical connection portion 131. Similarly, the negative electrode connection 160 may be configured to connect to another of the plurality of electrical connection portions 131, thereby enabling the negative electrode connection 160 to be electrically connected to the battery cell 110 corresponding to that electrical connection portion 131. Correspondingly, the end plate 120 is non-conductive, and the material of the end plate 120 need not be metal, thereby reducing the manufacturing cost of the end plate 120.

[0125] Specifically, the positive electrode connection portion 150 and the negative electrode connection portion 160 can be located adjacent to both sides of the cell stack 100 in the first direction, and the positive electrode connection portion 150 and the negative electrode connection portion 160 are electrically connected to the two outermost cells 110 located in the first direction of the cell stack 100. The positive electrode connection portion 150 and the negative electrode connection portion 160 can also be distributed along the second direction on both sides of the cell stack 100.

[0126] In some embodiments, at least a portion of the end plate 120 of this application may also be a thermally expandable structure, the end plate 120 being used to expand under heat to compress the battery cell 110. When the temperature of the end plate 120 increases, the end plate 120 expands toward the battery cell 110, so that the end plate 120 can provide a restraining force to the battery cell 110, thereby more precisely adjusting the restraining force acting on the battery cell 110.

[0127] When the battery cell 110 is charged and discharged and has a tendency to expand, the temperature of the battery cell 110 will increase accordingly. The heat of the battery cell 110 can be transferred to the end plate 120, so that the part of the end plate 120 that is a thermal expansion structure can be heated and expand towards the battery cell 110. This allows the end plate 120 to provide a restraining force acting on the battery cell 110, so as to more fully suppress the expansion force of the battery cell 110.

[0128] Specifically, the abutment portion 121 in the end plate 120 can be a thermally expanding structural component, and the winding portion 122 of the end plate 120 can be a non-thermally expanding structural component, so that the winding portion 122 can better support the restraint assembly 200.

[0129] In some embodiments, referring to Figures 4 and 5, the battery module 10 of this application may further include at least one thermal expansion member 140, which may be stacked on the cell 110 along a first direction. The thermal expansion member 140 is used to expand under heat to compress the cell 110. When the temperature of the thermal expansion member 140 increases, the thermal expansion member 140 expands toward the cell 110, so that the thermal expansion member 140 can provide a restraining force to the cell 110, thereby more precisely adjusting the restraining force acting on the cell 110.

[0130] When the battery cell 110 is charged and discharged and has a tendency to expand, the temperature of the battery cell 110 will increase accordingly. The heat of the battery cell 110 can be transferred to the thermal expansion member 140, so that the thermal expansion member 140 can expand towards the battery cell 110 due to heat. Thus, the thermal expansion member 140 can provide a restraining force acting on the battery cell 110 to more fully suppress the expansion force of the battery cell 110.

[0131] Specifically, the greater the heat generated by the battery cell 110, the greater its expansion tendency, and the greater the heat transferred from the battery cell 110 to the thermal expansion member 140, resulting in a greater degree of expansion of the thermal expansion member 140. This leads to a greater restraining force exerted by the thermal expansion member 140 on the battery cell 110, thus better suppressing the expansion tendency of the battery cell 110.

[0132] In some embodiments, the number of thermal expansion elements 140 in this application can be set to multiple, and the multiple thermal expansion elements 140 are stacked along a first direction. At least two thermal expansion elements 140 are arranged adjacent to each other so that the two thermal expansion elements 140 are stacked, and the two thermal expansion elements 140 have different coefficients of thermal expansion, that is, some thermal expansion elements 140 have a higher coefficient of thermal expansion, and other thermal expansion elements 140 have a lower coefficient of thermal expansion. When the number of thermal expansion elements 140 is two or more, the coefficients of thermal expansion of the multiple thermal expansion elements 140 can be different. Of course, when the number of thermal expansion elements 140 is two or more, at least two of the multiple thermal expansion elements 140 can also be set to have the same coefficient of thermal expansion.

[0133] Because the coefficients of thermal expansion of some of the thermal expansion components 140 differ, the heat from the battery cell 110 is conducted to each thermal expansion component 140, resulting in varying degrees of expansion. However, since the two stacked thermal expansion components 140 are interconnected, they cannot expand or contract freely; instead, they are mutually constrained. Due to this mutual constraint, when the temperature of the battery cell 110 rises and heat is transferred to the thermal expansion components 140, the component with the higher coefficient of thermal expansion expands more, while the component with the lower coefficient of thermal expansion expands less. This difference in expansion causes the stacked thermal expansion components 140 to bend and deform in a direction perpendicular to the first direction. Specifically, the component with the higher coefficient of thermal expansion expands outward, causing the overall structure formed by the stacked components to bend outward. The component with the lower coefficient of thermal expansion contracts inward, further exacerbating the outward bending tendency of the overall structure formed by the stacked components. The overall structure formed by the stacked thermal expansion members 140 exerts a greater restraining force on the battery cell 110, thereby more effectively suppressing the expansion tendency of the battery cell 110 in the first direction.

[0134] In some embodiments, referring to FIG5, among the plurality of thermal expansion elements 140 stacked sequentially along a first direction, the coefficient of thermal expansion of any one thermal expansion element 140 is higher or lower than the coefficient of thermal expansion of the thermal expansion elements 140 on opposite sides. That is, along the first direction, the coefficient of thermal expansion of the plurality of sequentially stacked thermal expansion elements 140 alternates between increasing and decreasing. This allows for a more precise degree of bending deformation of the overall structure formed by the plurality of sequentially stacked thermal expansion elements 140, thereby providing a more precise restraint force acting on the battery cell 110.

[0135] In some embodiments, referring to Figures 4 and 5, at least one thermal expansion member 140 is disposed between the end plate 120 and the adjacent cell 110, thereby ensuring that there is a thermal expansion member 140 between the end plate 120 and the adjacent cell 110, so that the thermal expansion member 140 can be connected to the end plate 120 and abut against the cell 110, so that the thermal expansion member 140 is installed stably.

[0136] In some embodiments, at least one thermal expansion member 140 is disposed between adjacent cells 110, thereby ensuring that there is a thermal expansion member 140 between adjacent cells 110, so that the restraining force generated by the thermal expansion of the thermal expansion member 140 can also act on the cell 110.

[0137] Based on the battery module 10 described above, this application also proposes a battery pack 20, as shown in Figure 10, which includes a tray 300 and the battery module 10 described above. The tray 300 is the basic component of the battery pack 20 of this application. The tray 300 can provide a mounting base for at least some other components of the battery pack 20 and serves to protect those components. The tray 300 can be made of metal, giving it better structural strength, thus improving its durability and reliability. Alternatively, some parts of the tray 300 can be made of polymer materials, allowing it to maintain a certain structural strength while remaining relatively lightweight.

[0138] The tray 300 has a battery cavity 310, which is a cavity-shaped structure within the tray 300. The battery module 10 can be disposed within the battery cavity 310 of the tray 300, thereby allowing the battery module 10 to be fixedly installed within the tray 300. The tray 300 also has an opening communicating with the battery cavity 310, through which the battery module 10 can be installed and removed from within the tray 300.

[0139] In some embodiments, along the first direction, the battery cavity 310 has two opposing abutting inner walls 311, and the opposite sides of the restraint assembly 200 abut against the two abutting inner walls 311 respectively. In this way, the tray 300 can also provide a restraining force acting on the cell stack 100 to more fully suppress the expansion tendency of the cell 110 along the first direction.

[0140] Referring to Figure 11, based on the battery module 10 or battery pack 20 described above, this application also proposes an electrical device 30, including the battery module 10 or battery pack 20 described above. This electrical device 30 can be a vehicle or an energy storage device.

[0141] In the description of this specification, the references to the terms "embodiment," "example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0142] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A battery module, characterized in that, include: A cell stack (100) includes a plurality of cells (110) stacked along a first direction, wherein each cell (110) has a tab (111) on one side along a second direction; A restraint assembly (200) is circumferentially wound around the cell stack (100) along the second direction, where the first direction and the second direction intersect.

2. The battery module according to claim 1, characterized in that, The first direction is the thickness direction of the battery cell (110), and the second direction is perpendicular to the first direction.

3. The battery module according to claim 1, characterized in that, The restraint assembly (200) forms a first orthographic projection on the surface of the cell stack (100), and the surface of the cell stack (100) covers the first orthographic projection.

4. The battery module according to claim 1, characterized in that, The restraint assembly (200) includes a plurality of restraint wires (210), which are spaced apart. Alternatively, multiple restraint wires (210) may be arranged adjacent to each other; Alternatively, at least some of the multiple restraint wires (210) may be stacked together.

5. The battery module according to claim 4, characterized in that, The restraint wire (210) is a carbon fiber wire and / or a metal wire.

6. The battery module according to claim 4, characterized in that, The cross-sectional area of ​​the restraint component (200) in the first direction satisfies: S1≥F / (2×Rm); Wherein, S1 is the cross-sectional area of ​​the restraint assembly (200) in the first direction, F is the preset restraint force acting on the cell stack (100), and Rm is the tensile strength of the restraint wire (210) in the first direction.

7. The battery module according to any one of claims 1-6, characterized in that, The cell stack (100) further includes at least one end plate (120), which is stacked on the cell (110) along the first direction, and the at least one end plate (120) is located outside the outermost cell (110) among the plurality of cells (110).

8. The battery module according to claim 7, characterized in that, The end plate (120) has an arc surface on the side opposite to the battery cell (110).

9. The battery module according to claim 7, characterized in that, The end plate (120) includes an abutting part (121) and a winding part (122). The abutting part (121) abuts against the battery cell (110). The two ends of the winding part (122) in the extending direction are respectively connected to the abutting part (121). There is a cavity (124) between the winding part (122) and the abutting part (121).

10. The battery module according to claim 9, characterized in that, The end plate (120) further includes a support portion (123), which is located in the cavity (124) and is connected to the abutment portion (121) and the winding portion (122).

11. The battery module according to claim 7, characterized in that, The end plate (120) forms a second orthographic projection on the cell (110) along the first direction, and the second orthographic projection is covered by the cell (110).

12. The battery module according to claim 11, characterized in that, The second orthographic projection coincides with the battery cell (110).

13. The battery module according to claim 7, characterized in that, At least two end plates (120) are located at both ends of the cell stack (100) along the first direction, and a plurality of cells (110) are electrically connected. The plurality of cells (110) are electrically connected to at least two end plates (120), and the at least two end plates (120) respectively form the positive terminal and the negative terminal of the cell stack (100).

14. The battery module according to claim 13, characterized in that, The cell stack (100) further includes an electrical connector (130) connected to the plurality of cells (110) and the two end plates (120).

15. The battery module according to claim 14, characterized in that, The electrical connector (130) includes a plurality of electrical connection portions (131), which connect to the tabs (111) of adjacent cells (110) and connect the end plate (120) to the adjacent cells (110).

16. The battery module according to claim 15, characterized in that, Positive electrode connection portion (150) and negative electrode connection portion (160) are respectively provided on opposite sides of the two end plates (120), and the positive electrode connection portion (150) and the negative electrode connection portion (160) are electrically connected to the corresponding end plate (120).

17. The battery module according to any one of claims 1-6, characterized in that, The battery module (100) further includes a positive electrode connection part (150) and a negative electrode connection part (160), both of which are electrically connected to the battery cell (110). The positive electrode connection part (150) and the negative electrode connection part (160) respectively constitute the positive electrode connection end and the negative electrode connection end of the battery cell stack (100).

18. The battery module according to claim 17, characterized in that, The positive electrode connection (150) is electrically connected to one of the outermost of the plurality of battery cells (110), and the negative electrode connection (160) is electrically connected to another of the outermost of the plurality of battery cells (110).

19. The battery module according to claim 7, characterized in that, At least a portion of the end plate (120) is a thermal expansion structure, the end plate (120) being used to expand under heat to compress the battery cell (110).

20. The battery module according to claim 7, characterized in that, The cell stack (100) further includes at least one thermal expansion member (140), at least one of the thermal expansion members (140) being stacked on the cell (110) along the first direction, the thermal expansion member (140) being used to expand under heat to compress the cell (110).

21. The battery module according to claim 20, characterized in that, At least two of the thermal expansion elements (140) are adjacent along the first direction and have different coefficients of thermal expansion.

22. The battery module according to claim 21, characterized in that, Among the plurality of thermal expansion members (140) stacked sequentially along the first direction, the coefficient of thermal expansion of any one of the thermal expansion members (140) is higher or lower than the coefficient of thermal expansion of the thermal expansion members (140) on opposite sides.

23. The battery module according to claim 20, characterized in that, At least one of the thermal expansion members (140) is disposed between adjacent cells (110).

24. The battery module according to claim 20, characterized in that, At least one of the thermal expansion members (140) is disposed between the end plate (120) and the adjacent cell (110).

25. A battery pack, characterized in that, Includes a tray (300) and a battery module (10) as claimed in any one of claims 1-24, the tray (300) having a battery cavity (310) and the battery module (10) disposed within the battery cavity (310).

26. The battery pack according to claim 25, characterized in that, Along the first direction, the battery cavity (310) has two opposing abutting inner walls (311), and the opposite sides of the restraint assembly (200) abut against the two abutting inner walls (311) respectively.

27. An electrical device comprising a battery module (10) as claimed in any one of claims 1-24, or comprising a battery pack (20) as claimed in claim 25 or 26.

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