Battery monomer and preparation method thereof, battery device, power utilization device and energy storage device

Abstract

The invention relates to a battery monomer and a preparation method thereof, a battery device, a power utilization device and an energy storage device, the battery monomer comprises an electrode assembly and a top cover assembly, the top cover assembly comprises a bright aluminum sheet and lower plastic, and the lower plastic is arranged on one side, facing the electrode assembly, of the bright aluminum sheet; the light aluminum sheet comprises at least one through hole protruding towards one side of the lower plastic, and the circumferential side wall of the through hole is provided with a flange extending outwards; the lower plastic comprises at least one clamping part which is arranged in a protruding mode towards one side of the light aluminum sheet, and the clamping parts are connected with the turnup in a clamped mode. The flanging of the circumferential side wall of the through hole is clamped with the clamping part, so that the far end of the lower plastic of the large-size or longer battery cell top cover is prevented from warping, and the assembly clearance is reduced. Due to the mechanical interlocking of the turned-over edge and the clamping part, an adhesive is not needed, and the risk of electrolyte pollution is avoided. The turned-over edge is of a protruding structure which is opened outwards, and metal filing is easy to clean. The through hole structure can be formed through die stamping, the production efficiency is high, the technological process is simplified, and the manufacturing cost is reduced.

Description

Technical Field

[0001] This application relates to the field of battery manufacturing technology, and in particular to battery cells and their preparation methods, battery devices, power-consuming devices, and energy storage devices. Background Technology

[0002] With the accelerated global energy structure transformation, energy storage technologies, especially electrochemical energy storage, are being increasingly widely used in power systems and new energy vehicles. The energy density and capacity requirements of battery systems are constantly increasing, and the size of battery cells is also continuously growing. As a component that ensures the sealing of the battery's internal environment, enables electrical connections, and provides safety protection, the structural design of the cell top cover directly affects the overall performance and reliability of high-capacity or long-size cells. Reliable connections between top cover components, such as between the plastic and metal sheets, ensure the structural integrity of the top cover and prevent electrolyte leakage. Summary of the Invention

[0003] Therefore, it is necessary to provide a battery cell and its preparation method, battery device, power consumption device, and energy storage device to address the connection reliability between the top cover components of the battery cell.

[0004] A battery cell includes an electrode assembly and a top cover assembly, the top cover assembly including a light aluminum sheet and a lower plastic sheet, the lower plastic sheet being disposed on the side of the light aluminum sheet facing the electrode assembly;

[0005] The aluminum sheet includes at least one through hole protruding toward the lower plastic side, and the circumferential sidewall of the through hole is provided with an outwardly extending flange.

[0006] The lower plastic includes at least one engaging portion protruding toward one side of the aluminum sheet, the engaging portion engaging with the flange.

[0007] In one embodiment, the through hole includes an opening that is recessed at one end of the through hole toward the side of the aluminum sheet.

[0008] In one embodiment, the flange extends outward from the circumferential sidewall of the through hole along a first direction.

[0009] In one embodiment, the through hole is an annular structure, the sidewall of the through hole extends from the aluminum sheet along a second direction toward the lower plastic side, and the flange is connected to the end of the opening.

[0010] In one embodiment, the flange is an annular flange circumferentially disposed around the sidewall of the annular through hole.

[0011] In one embodiment, the lower plastic includes a recess, the recess having a mounting hole that mates with the through hole, the mounting hole being an annular hole penetrating the lower plastic.

[0012] In one embodiment, the engaging portion includes a hook, one end of which is disposed on the side wall of the mounting hole, and the other end extends along a first direction. The surface of the hook that contacts the flange is a plane.

[0013] In one embodiment, the annular flange includes a first surface and a second surface, the first surface being disposed at the end of the opening, and the first surface having an angle with the plane containing the end of the opening; the second surface being connected to the first surface and disposed parallel to the first direction.

[0014] In one embodiment, the surface of the aluminum sheet away from the lower plastic is provided with at least one inwardly recessed countersunk hole, which is located above the through hole.

[0015] In one embodiment, the diameter of the countersunk hole is A, and the diameter A of the countersunk hole satisfies: 5mm≤A≤15mm;

[0016] The height of the aluminum sheet is H, and the height of the countersunk hole is H1. The height H of the aluminum sheet and the height H1 of the countersunk hole satisfy: H / 3≤H1≤2H / 3.

[0017] In one embodiment, the height of the sidewall of the through hole is H2, the height of the flange to the surface of the aluminum sheet is H3, the inner diameter of the opening is B, and the outer diameter of the opening is C.

[0018] The height H3 of the flange to the surface of the aluminum sheet satisfies: 0.8mm≤H3<5mm; the height H2 of the sidewall of the through hole and the height H3 of the flange to the surface of the aluminum sheet satisfy: 0.5mm≤(CB) / 2=H2-H3≤1.5mm.

[0019] In one embodiment, the outer diameter of the flange is D, and the outer diameter D of the flange and the outer diameter C of the opening satisfy: 0.5mm≤(DC) / 2≤1.5mm.

[0020] In one embodiment, the height H1 of the countersunk hole, the height H2 of the sidewall of the through hole, and the height H3 of the flange to the surface of the aluminum sheet satisfy: (C 2 -B 2 )*H3+(D 2 -C 2 ) * (H2 - H3) ≤ 0.8 * A 2 *H1.

[0021] The top cover assembly of the aforementioned battery cell uses a flanged sidewall with through-holes that engages with a locking mechanism to suppress warping of the lower plastic distal end in the top cover of large or long cells, thus reducing assembly gaps. Due to the mechanical interlocking of the flange and the locking mechanism, no adhesive is needed, avoiding the risk of electrolyte contamination. The flange is an outwardly open protruding structure, facilitating the removal of metal shavings. The through-hole structure can be formed by die stamping, resulting in high production efficiency, simplified process flow, and reduced manufacturing costs.

[0022] According to another objective of the present invention, a method for preparing a battery cell is also provided, comprising:

[0023] The aluminum sheet is stamped to form at least one raised through hole;

[0024] The through hole is stretched to form a flange extending in the first direction;

[0025] The snap-fit ​​part on the lower plastic is snapped onto the flange.

[0026] In one embodiment, the step of stretching the through hole further includes:

[0027] The end of the through hole is stamped to form an inwardly recessed opening;

[0028] The circumferential sidewalls of the opening are stretched.

[0029] The sidewalls are flanged to form a circular flange.

[0030] The aforementioned method for manufacturing battery cells employs a raised flange structure formed by stamping, stretching, and flanging processes. This avoids the deep-hole dead corners produced by traditional cold heading and countersinking processes, making it easier to clean metal shavings and improving the cleanliness of the top cover assembly. Simultaneously, it replaces the two complex processes of traditional cold heading and hot melting with continuous stamping, resulting in high efficiency and low cost. Press fitting requires no heating, thus saving energy, simplifying the production process, and reducing manufacturing costs.

[0031] According to another objective of the present invention, a battery device is also provided, comprising a plurality of battery cells as described above, the battery device comprising one or more of a battery module, a battery pack, and an energy storage battery.

[0032] According to another object of the present invention, an electrical device is also provided, comprising a battery device as described above, the battery device being used to provide electrical energy.

[0033] According to another object of the present invention, an energy storage device is also provided, comprising a battery device as described above, the battery device being used to store electrical energy. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the top cover assembly.

[0035] Figure 2 This is an exploded view of the top cover assembly.

[0036] Figure 3 This is a front view of the top cover assembly.

[0037] Figure 4 This is a side view of the top cover assembly.

[0038] Figure 5 This is a cross-sectional view of the top cover assembly along the AA direction.

[0039] Figure 6 This is a partially enlarged view of the cross-sectional schematic diagram of the top cover assembly.

[0040] Figure 7 This is a cross-sectional schematic diagram of a light aluminum sheet.

[0041] Figure 8 This is a schematic diagram of the process for preparing a single battery cell.

[0042] Figure 9 This is a schematic diagram of the structure of a single battery cell.

[0043] Figure 10 This is a schematic diagram of an explosion of a single battery cell.

[0044] In the diagram: 10. Plain aluminum sheet; 11. Through hole; 111. Opening; 112. Side wall; 113. End; 12. Flanged edge; 121. First surface; 122. Second surface; 13. Countersunk hole;

[0045] 20. Bottom plastic part; 21. Engaging part; 211. Hook; 22. Recessed groove; 23. Mounting hole;

[0046] 30. Top plastic; 40. Terminal post; 50. Sealing ring; 60. Welding ring; 70. Explosion-proof sticker; 80. Explosion-proof valve;

[0047] 100. Battery cell; 101. Top cover assembly; 102. Electrode assembly; 103. Housing; 104. Tab;

[0048] A. Diameter of the countersunk hole; H. Height of the aluminum sheet; H1. Height of the countersunk hole; H2. Height of the sidewall of the through hole; H3. Height of the flange to the surface of the aluminum sheet; B. Inner diameter of the opening; C. Outer diameter of the opening; D. Outer diameter of the flange. Detailed Implementation

[0049] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0050] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and 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.

[0051] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0052] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0053] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0054] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0055] In fields such as energy storage and electric vehicles, with the continuous increase in the demand for energy density and capacity of battery systems, the size of battery cells, especially their length, continues to increase. The length of the new generation of higher-capacity cells has exceeded that of conventional 280Ah cells, with top cover lengths exceeding 300mm, and even reaching 400mm or longer. However, the increase in cell size affects the stability of the top cover structure.

[0056] Currently, the methods for fixing the lower plastic and the aluminum sheet generally include terminal crimping, double-sided adhesive bonding, or cold heading and countersinking with heat fusion. Terminal crimping involves pressing a portion of the lower plastic between the terminal and the aluminum sheet. However, for longer cells, relying solely on pressure at a single point on the terminal is insufficient to control the gap between the lower plastic and the aluminum sheet along the entire length. In the long side region far from the crimping point, the lower plastic is more prone to warping due to the lack of constraint, resulting in poor flatness of the top cover and affecting subsequent assembly.

[0057] Double-sided adhesive bonding involves applying double-sided adhesive between the contact surfaces of the lower plastic sheet and the aluminum sheet. However, the adhesive poses a risk of contaminating the electrolyte during long-term battery use; adhesive aging can lead to decreased bonding strength, causing partial or complete detachment of the lower plastic sheet.

[0058] Cold heading countersunk holes are fixed by hot melting. This process involves cold heading a flat aluminum sheet to create countersunk holes with undercuts, while a corresponding boss is placed in the lower plastic part. During assembly, the lower plastic boss is heated and melted using a hot melting device, filling the undercut of the countersunk hole. After cooling, an interlocking mechanism is formed. However, the dead corners created inside the countersunk hole make it difficult to remove metal shavings generated during stamping, and these residues can pose a risk of internal short circuits in the battery. Furthermore, the cold heading process itself can easily cause plastic deformation of large-sized flat aluminum sheets in the countersunk hole area, affecting the overall flatness and assembly accuracy of the top cover.

[0059] See Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 1 A schematic diagram of the top cover assembly 101 in one embodiment of this application is shown. Figure 2 An exploded view of the top cover assembly 101 in one embodiment of this application is shown. Figure 3 A front view of the top cover assembly 101 according to an embodiment of this application is shown. Figure 4 A side view of the top cover assembly 101 in one embodiment of this application is shown.

[0060] To address the aforementioned technical problems, one embodiment of this application provides a battery cell 100, including an electrode assembly 102 and a top cover assembly 101. The top cover assembly 101 includes an aluminum sheet 10 and a lower plastic layer 20, with the lower plastic layer 20 disposed on the side of the aluminum sheet 10 facing the electrode assembly 102. The aluminum sheet 10 includes at least one through-hole 11 protruding towards the lower plastic layer 20, and the circumferential sidewall 112 of the through-hole 11 has an outwardly extending flange 12. The lower plastic layer 20 includes at least one engaging portion 21 protruding towards the aluminum sheet 10, which engages with the flange 12. The engagement of the flange 12, which is circumferentially disposed on the sidewall 112 of the through-hole 11 on the aluminum sheet 10, with the engaging portion 21 of the lower plastic layer 20, improves the structural integrity of the top cover assembly 101 for large or long battery cells and enhances the reliability of connections between the top cover assemblies 101.

[0061] Combination Figure 9 and Figure 10 As shown, Figure 9 This is a schematic diagram of the structure of a battery cell 100 provided in one embodiment of this application. Figure 10 This is an exploded view of a battery cell 100 provided in one embodiment of this application. In this embodiment, the battery cell 100 includes a top cover assembly 101, an electrode assembly 102, a housing 103, and tabs 104. The electrode assembly 102 is disposed within the housing 103 and serves as the energy storage component of the battery cell 100. It is formed by winding or stacking positive electrode sheets, negative electrode sheets, and a separator. The housing 103 is an aluminum shell to protect the electrode assembly 102. The tabs 104 are used to connect to the terminal post 40.

[0062] The top cover assembly 101 is sealed at the top of the housing 103 and serves as the electrical output terminal of the battery cell 100. The top cover assembly 101 is a multi-layer composite structure, including a welding ring 60, an upper plastic 30, a light aluminum sheet 10, a sealing ring 50, a lower plastic 20, a terminal post 40, and components such as an explosion-proof valve 80 and an explosion-proof sticker 70.

[0063] The welding ring 60 is located on the outermost side of the top cover assembly 101. The upper plastic 30 is disposed inside the welding ring 60 and is made of one or more of polypropylene, polyphenylene sulfide, or polyamide. The upper plastic 30 includes a through hole 11 for the electrode post 40 to pass through. The aluminum sheet 10, which is the conductive body of the top cover assembly 101, is disposed below the upper plastic 30 and is made of aluminum alloy.

[0064] The sealing ring 50 is made of insulating materials such as rubber and is disposed between the aluminum sheet 10 and the lower plastic 20, or around the electrode post 40. The lower plastic 20 is disposed on the side of the aluminum sheet 10 facing the electrode assembly 102, and serves as insulation and auxiliary sealing. The lower plastic 20 is made of one or more of polypropylene, polyphenylene sulfide, or polyamide.

[0065] The terminal 40 includes a positive terminal 40 and a negative terminal 40, both made of conductive metal. The terminal 40 passes through the connecting holes on the upper plastic 30, the aluminum sheet 10, the sealing ring 50, and the lower plastic 20. Its lower end is connected to the tab 104 of the electrode assembly 102, and its upper end serves as a terminal for the battery to connect to external power.

[0066] An explosion-proof valve 80 is mounted on the aluminum sheet 10. When the internal pressure of the battery abnormally rises to a set value, the weak point of the explosion-proof valve 80 ruptures, releasing the internal pressure and preventing the battery from exploding. An explosion-proof sticker 70 is a breathable explosion-proof film assembly mounted on the explosion-proof valve 80. It allows gas to escape or blocks external foreign objects while preventing electrolyte splashing.

[0067] Combination Figure 5 and Figure 6 As shown, Figure 5 This is a schematic cross-sectional view of the top cover assembly 101 provided in one embodiment of this application along the AA direction. Figure 6 This is a partially enlarged cross-sectional view of the top cover assembly 101 provided in one embodiment of this application.

[0068] At least one through hole 11 protruding towards the lower plastic 20 is integrally formed on the aluminum sheet 10 by a die stamping process. Specifically, the forming process of the through hole 11 includes: embossing the aluminum sheet 10 blank to form a boss; stretching the boss to form a cylindrical part with a circumferential sidewall 112; and flanging the end 113 of the cylindrical part to form a flanged edge 12 extending outward from the end 113 of the circumferential sidewall 112. "Extending outward" means extending along a first direction, that is, along a direction parallel to the length of the aluminum sheet 10, so that the circumferential sidewall 112 of the through hole 11 and the flanged edge 12 together constitute a protruding structure with a buckling function.

[0069] The lower plastic 20 is provided with a locking part 21 corresponding to the position of the through hole 11. The locking part 21 protrudes toward the light aluminum sheet 10. Specifically, the locking part 21 includes a hook 211 arranged around the position of the through hole 11, which is used to engage and fix with the flange 12.

[0070] In the specific implementation process, the engaging part 21 of the lower plastic 20 is aligned with the flange 12 on the circumferential sidewall 112 of the through hole 11, and pressure is applied in a direction perpendicular to the aluminum sheet 10. The hook 211 of the engaging part 21 abuts against the inclined surface or edge of the flange 12, compressing and deforming the flange 12 until the hook 211 and the flange 12 engage with each other, thereby fixing the lower plastic 20 and the aluminum sheet 10.

[0071] The top cover assembly 101 of the aforementioned battery cell 100, through the engagement of the flange 12 of the circumferential sidewall 112 with the through hole 11 and the hook 211 of the lower plastic 20, distributes the force in the circumferential direction of the engagement part 21. This ensures that on the top cover of a longer or larger battery cell, the tight fit between the lower plastic 20 and the aluminum sheet 10 can resist the tendency of the long side or far end to warp due to the deformation of the component itself or external stress, and reduce the assembly gap between the two.

[0072] Due to the mechanical interlocking between the flange 12 and the engaging part 21, no adhesive is needed, avoiding the risk of adhesive contamination of the electrolyte. Simultaneously, the flange 12 is an outwardly open protruding structure, eliminating any sealed dead corners compared to traditional undercut structures. This allows metal shavings to be easily washed away during the cleaning process, improving the problem of metal shaving residue. The through-hole 11 structure can be formed by die stamping, resulting in high production efficiency, eliminating the equipment and processes required for hot-melt welding, simplifying the process flow, and reducing manufacturing costs.

[0073] In one embodiment, the through hole 11 includes an opening 111, which is formed by recessing the end 113 of the through hole 11 toward the side of the light aluminum sheet 10.

[0074] The through hole 11 includes an opening 111, which is formed at the end 113 of the through hole 11, that is, the end away from the body of the aluminum sheet 10 and close to the lower plastic 20. The opening 111 is formed by a recess in the end 113 of the through hole 11 toward the body of the aluminum sheet 10.

[0075] The opening 111 can have various cross-sectional shapes. Specifically, the cross-section of the opening 111 is an annular recess, such as an annular or cylindrical shape, with a smooth transition surface. Alternatively, the cross-section of the opening 111 is an arc-shaped recess, such as a bowl shape or a trumpet shape, with a smooth transition surface. Alternatively, the cross-section of the opening 111 is a conical recess, with the sidewall 112 being a slope.

[0076] When the engaging part 21 engages with the flange 12 and bears the force, the surface or sidewall 112 of the recessed structure opening 111 can disperse the stress, reduce stress concentration, reduce the risk of plastic deformation of the aluminum sheet 10 in the area due to long-term stress, and improve long-term reliability.

[0077] Furthermore, the depth of the opening 111 is the maximum distance from the end 113 of the unrecessed through hole 11 to the bottom of the recessed area. The depth of the opening 111 is less than the height of the circumferential sidewall 112 of the through hole 11, ensuring that the recessed structure does not weaken the main supporting part of the sidewall 112, thus providing a guiding function while ensuring the overall strength and stability of the raised structure.

[0078] Furthermore, the inner diameter at the opening 111, i.e. the diameter at the recessed edge, can be slightly smaller than the outer diameter of the circumferential sidewall 112 at the end 113, to ensure the connection strength between the flange 12 on the circumferential sidewall 112 and the engaging part 21, and to ensure the connection stability.

[0079] Combination Figure 5 and Figure 6 As shown, Figure 5 This is a schematic cross-sectional view of the top cover assembly provided in one embodiment of this application along the AA direction. Figure 6 This is a partially enlarged cross-sectional view of the top cover assembly 101 provided in one embodiment of this application. In one embodiment, the flange 12 extends outward from the circumferential sidewall 112 of the through hole 11 along a first direction.

[0080] The first direction refers to the direction along the length of the aluminum sheet 10. The flange 12 extends from the end 113 of the circumferential sidewall 112 of the through hole 11 along the first direction, forming a protruding, annular or partially annular structure at the end 113, such that the outer edge of the flange 12 protrudes from the outer surface of the circumferential sidewall 112 in the first direction, for engaging with the engaging part 21 of the lower plastic 20.

[0081] Furthermore, the extension length of the flange 12 along the first direction is greater than or equal to the width of the sidewall 112 in the first direction. That is, in the first direction, the extension length of the flange 12 is greater than or equal to the thickness of the sidewall 112, ensuring that the flange 12 has sufficient connection position to facilitate engagement with the engaging part 21 and improve connection stability. At the same time, the relatively long length of the flange 12 ensures that the connection portion between the flange 12 and the sidewall 112 has sufficient strength, ensuring the connection strength with the engaging part 21.

[0082] By setting the extension length of flange 12, the stress distribution in the region is optimized. A shorter extension length helps reduce bending moment and improve structural stiffness; a longer extension length provides a larger snap-fit ​​contact area and guide ramp, facilitating assembly.

[0083] During assembly, the lower plastic 20 engaging part 21 can move along the edge of the end 113 of the aforementioned outwardly extending flange 12, thereby causing the engaging part 21 to undergo elastic deformation during the pressing process until it engages with the flange 12, thus improving assembly efficiency.

[0084] In one embodiment, the through hole 11 is an annular structure, the sidewall 112 of the through hole 11 extends from the aluminum sheet 10 along the second direction toward the lower plastic 20, and the flange 12 is connected to the end 113 of the opening 111.

[0085] The second direction refers to the direction along the thickness or height of the aluminum sheet 10, which is the vertical direction shown in the figure. The through hole 11 extends downward along the second direction, that is, along the thickness direction of the aluminum sheet 10, to form a ring-shaped or annular structure. That is, the through hole 11 includes an annular circumferential sidewall 112.

[0086] The annular sidewalls 112 and flanges 12 are continuously distributed circumferentially, providing uniform constraint force to the engaging portion 21 of the lower plastic 20, thus avoiding the risk of insufficient constraint, torsion, or local warping of the lower plastic 20 in a certain direction.

[0087] The flange 12 is connected to the end 113 of the opening 111, that is, to the edge area formed by the end of the opening 111 away from the light aluminum sheet 10. The force that causes the lower plastic 20 to detach is transmitted through the flange 12 to the connection point between it and the end 113 of the side wall 112. The force transmission path is short, and the flange 12 is located at the outermost end, which can provide restraint for the engaging part 21 and ensure the firmness of the engagement.

[0088] In one embodiment, the flange 12 is an annular flange 12 circumferentially disposed around the sidewall 112 of the annular through hole 11.

[0089] The annular flange 12 extends outward from the end 113 of the annular sidewall 112 of the through hole 11 along a direction parallel to the length of the aluminum sheet 10, forming an annular flange or annular lip that surrounds the sidewall 112. Compared to the traditional undercut structure, when the lower plastic 20 is subjected to a force that causes it to detach from the aluminum sheet 10, the force is evenly distributed onto the annular flange 12, avoiding local stress concentration, ensuring stable connection, preventing the lower plastic 20 from warping or loosening, and improving reliability.

[0090] Furthermore, the outer edge of the annular flange 12 forms a smooth arc surface or rounded corner guide surface to serve as a transition surface between the flange 12 and the end 113 of the side wall 112. During the assembly and pressing process of the lower plastic 20, the engaging part 21 of the lower plastic 20 can contact the guide surface of the annular flange 12, smoothly engaging with the flange 12 and improving the assembly speed.

[0091] Combination Figure 3 and Figure 6 As shown, Figure 3 This is a front view of the top cover assembly 101 provided in one embodiment of this application. Figure 6 This is a partially enlarged cross-sectional view of the top cover assembly 101 provided in one embodiment of this application. In one embodiment, the lower plastic 20 includes a recess 22, and the recess 22 is provided with a mounting hole 23 that mates with the through hole 11. The mounting hole 23 is an annular hole that penetrates the lower plastic 20.

[0092] The lower plastic 20 includes a recess 22. The recess 22 is a recessed area formed on the surface of the lower plastic 20 facing the aluminum sheet 10. The recess 22 has a mounting hole 23 that mates with the through hole 11 on the aluminum sheet 10. The mounting hole 23 is an annular hole that penetrates the lower plastic 20, and its penetration direction is consistent with the assembly pressing direction of the lower plastic 20.

[0093] After the lower plastic 20 and the aluminum sheet 10 are assembled in place, the protruding structure on the aluminum sheet 10 can be partially or completely embedded in the recess 22, which helps to reduce the overall thickness of the top cover assembly 101 or achieve a more compact layout. In addition, the side wall 112 of the recess 22 can provide positioning and limiting for the protruding structure of the aluminum sheet 10, as well as assist in the assembly alignment of the two, thereby improving assembly efficiency.

[0094] Furthermore, the mounting hole 23 is an annular hole, and its inner diameter is slightly larger than the outer diameter of the annular sidewall 112 of the through hole 11 of the aluminum sheet 10, so that part of the annular sidewall 112 passes through the mounting hole 23, and the annular flange 12 on it engages with the engaging part 21 on the mounting hole 23.

[0095] In one embodiment, the engaging part 21 includes a hook 211, one end of which is disposed on the side wall 112 of the mounting hole 23, and the other end extends along a first direction. The surface of the hook 211 that contacts the flange 12 is a plane.

[0096] The engaging portion 21 includes one or more hooks 211. In this embodiment, the engaging portion 21 includes four hooks 211, which are circumferentially spaced around the inner sidewall 112 of the annular hole. One end of each hook 211 is disposed on the sidewall 112 of the mounting hole 23 and is integrally formed with the lower plastic body 20. The other end of the hook 211 protrudes toward the side of the aluminum sheet 10 and extends along a first direction to form a hook-shaped structure. The surface of the protruding end of the hook 211 makes planar contact with the surface of the annular flange 12 of the aluminum sheet 10, thereby achieving the engagement between the two.

[0097] Furthermore, the surface on which the hook 211 contacts the annular flange 12 on the aluminum sheet 10 is flat. Compared to point or line contact, flat contact has lower contact stress under the same locking force, reducing potential plastic deformation or wear during long-term use and improving long-term stability. Flat contact ensures that the locking force acts perpendicularly to the contact surface, making it less likely to generate lateral forces that could cause the hook 211 to twist or slip, resulting in a more stable locking state.

[0098] Combination Figure 6 As shown, Figure 6 This is a partially enlarged cross-sectional view of the top cover assembly 101 provided in one embodiment of this application. In one embodiment, the annular flange 12 includes a first surface 121 and a second surface 122. The first surface 121 is disposed at the end 113 of the opening 111, and there is an angle between the first surface 121 and the plane containing the end 113 of the opening 111. The second surface 122 is connected to the first surface 121 and is disposed parallel to the first direction.

[0099] The annular flange 12 includes a first surface 121. The first surface 121 is disposed at the end 113 of the opening 111. It can be understood that the first surface 121 is the starting surface or root transition surface connecting the annular flange 12 and the end 113 of the annular sidewall 112.

[0100] Furthermore, there is an angle between the plane containing the first surface 121 and the plane containing the end 113 of the opening 111. Because of this angle, a guide slope is formed. During the assembly of the lower plastic 20, when the engaging part 21 contacts the flange 12, it interacts with the slope. The slope guides the hook 211 to the highest point of the flange 12 until it engages with the flange 12. The slope structure achieves a smooth transition from the annular sidewall 112 to the outer edge of the flange 12, reducing stress concentration at the connection point and improving the fatigue and fracture resistance of the flange 12.

[0101] Furthermore, the included angle between the first surface 121 and the plane containing the end 113 of the opening 111 is 30°-60°. Specifically, the included angle is one of 30°, 35°, 40°, 45°, 50°, 55°, and 60°. For example, the included angle is 45°. When the included angle is 30°-40°, a smaller angle provides a smoother guide and makes assembly easier. When the included angle is 50°-60°, a larger angle is used, making the structure at the root of the flange 12 more compact.

[0102] The annular flange 12 also includes a second surface 122. The second surface 122 is connected to the first surface 121, together forming the outer edge of the annular flange 12. The second surface 122 is arranged parallel to the first direction, that is, the second surface 122 is a plane. The planar contact surface of the hook 211 forms a planar contact with the second surface 122 of the flange 12, preventing relative movement between the hook 211 and the flange 12 and ensuring reliable engagement.

[0103] Combination Figure 7 As shown, Figure 7 This is a cross-sectional schematic diagram of the aluminum sheet 10 provided in one embodiment of this application. In one embodiment, the surface of the aluminum sheet 10 away from the lower plastic 20 is provided with at least one inwardly recessed countersunk hole 13, which is disposed above the through hole 11.

[0104] The surface of the aluminum sheet 10 away from the lower plastic 20, i.e., the outer surface of the aluminum sheet 10, is provided with at least one inwardly recessed countersunk hole 13. Here, inwardly recessed means recessed along the second direction, i.e., the thickness direction of the aluminum sheet 10, toward the interior of the aluminum sheet 10 or toward the side of the lower plastic 20.

[0105] A countersunk hole 13 is disposed above a through hole 11. Along a direction perpendicular to the aluminum sheet 10, the projected areas of the countersunk hole 13 and the through hole 11 at least partially overlap, or the projected area of ​​the countersunk hole 13 is larger than the projected area of ​​the through hole 11. The central axis of the countersunk hole 13 coincides with the central axis of the corresponding through hole 11.

[0106] While forming the through hole 11 protruding towards the lower plastic 20 using a stamping process, a countersunk hole 13 is simultaneously formed on the back side of the through hole 11. By setting the countersunk hole 13, the thickness of the aluminum sheet 10 in the area of ​​the through hole 11 is locally reduced, thereby reducing the local weight of the aluminum sheet 10 and achieving weight reduction.

[0107] Furthermore, the recessed area formed by the countersunk hole 13 provides space for other components, such as insulating sheets and signal acquisition components, reducing the stacking height of the top cover.

[0108] Furthermore, when the through hole 11 is annular, the countersunk hole 13 is also annular. The diameter of the countersunk hole 13 can be slightly larger than the diameter of the bottom of the through hole 11. The depth of the countersunk hole 13, that is, the distance from the outer surface of the aluminum sheet 10 to the bottom surface of the countersunk hole 13, is 1 / 3 to 2 / 3 of the thickness of the aluminum sheet 10.

[0109] The sidewall 112 of the countersunk hole 13 is a straight wall, an inclined wall, or a rounded corner. The bottom surface of the countersunk hole 13 is a flat surface or an arc surface.

[0110] Combination Figure 7 As shown, Figure 7 This is a cross-sectional schematic diagram of the aluminum sheet 10 provided in one embodiment of this application. In one embodiment, the diameter of the countersunk hole 13 is A, and the diameter A of the countersunk hole 13 satisfies: 5mm≤A≤15mm; the height of the aluminum sheet 10 is H, and the height of the countersunk hole 13 is H1, and the height H of the aluminum sheet 10 and the height H1 of the countersunk hole 13 satisfy: H / 3≤H1≤2H / 3.

[0111] The diameter of the countersunk hole 13 is A. The diameter A of the countersunk hole 13 satisfies the following range: 5mm ≤ A ≤ 15mm, ensuring that the countersunk hole 13 can cover and correspond to the formed area of ​​the through hole 11. Further, the diameter A of the countersunk hole 13 is one of 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, and 15mm.

[0112] If the diameter A of the countersunk hole 13 is less than 5mm, the area of ​​the countersunk hole 13 is too small, and its optimization effect is weakened. At the same time, an excessively small countersunk hole 13 increases the difficulty of stamping and forming, which is not conducive to ensuring the consistency and strength of the structure. If the diameter A of the countersunk hole 13 is greater than 15mm, the area occupied by the countersunk hole 13 is too large, which weakens the overall flatness and structural rigidity of the aluminum sheet 10 in the area; an excessively large countersunk hole 13 may encroach on the arrangement space of other functional components, such as the pole post 40 and the explosion-proof valve 80, affecting the compactness of the top cover.

[0113] The height of the countersunk hole 13, i.e., the vertical distance from the outer surface of the aluminum sheet 10 to the bottom surface of the countersunk hole 13, is H1. Simultaneously, the overall material thickness of the aluminum sheet 10, i.e., the total height H from the outer surface of the aluminum sheet 10 to the corresponding position facing the lower plastic 20, is H. The total height H of the aluminum sheet 10 and the height H1 of the countersunk hole 13 satisfy the following proportional relationship: H / 3 ≤ H1 ≤ 2H / 3. That is, the ratio between the height H1 of the countersunk hole 13 and the total height H of the aluminum sheet 10 is between 0.33 and 0.67.

[0114] Furthermore, the ratio between the height H1 of the countersunk hole 13 and the total height H of the aluminum sheet 10 is one of 0.33, 0.4, 0.45, 0.5, 0.55, 0.6, and 0.67.

[0115] The height H1 of the countersunk hole 13 is at least one-third of the total height H to ensure sufficient recess depth and guarantee the forming height of the through hole 11. The height H1 of the countersunk hole 13 is at most two-thirds of the total height H to ensure sufficient minimum remaining material thickness between the bottom of the countersunk hole 13 and the through hole 11, maintain the structural integrity of the area, and avoid the risk of plastic deformation due to stress during long-term use.

[0116] In one embodiment, the height of the sidewall 112 of the through hole 11 is H2, the height of the flange 12 to the surface of the aluminum sheet 10 is H3, the inner diameter of the opening 111 is B, and the outer diameter of the opening 111 is C; the height H3 from the flange 12 to the surface of the aluminum sheet 10 satisfies: 0.8mm≤H3<5mm; the height H2 of the sidewall 112 of the through hole 11 and the height H3 from the flange 12 to the surface of the aluminum sheet 10 satisfy: 0.5mm≤(CB) / 2=H2-H3≤1.5mm.

[0117] The height H2 of the sidewall 112 of the through hole 11 refers to the vertical distance of the annular sidewall 112 of the through hole 11 from its connection with the body of the aluminum sheet 10 to its end 113.

[0118] The height H3 from the flange 12 to the surface of the aluminum sheet 10 refers to the vertical distance from the lower surface of the annular flange 12, i.e. the surface that contacts the engaging part 21, to the surface of the aluminum sheet 10 facing the lower plastic 20.

[0119] The through hole 11 has an opening 111 at its end 113 facing the lower plastic 20. The diameter of the inner edge of the opening 111 is B; the diameter of the outer edge of the opening 111, i.e., the outer edge of the end 113 of the annular sidewall 112, is C. For the sidewall 112 with a uniform wall thickness, C = B + 2 * the thickness of the sidewall 112 is satisfied.

[0120] The height H3 of the flange 12 to the surface of the aluminum sheet 10 satisfies: 0.8mm ≤ H3 < 5mm. Further, the height H3 of the flange 12 to the surface of the aluminum sheet 10 is one of 0.8mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, and 5mm.

[0121] If the height H3 from the flange 12 to the surface of the aluminum sheet 10 is less than 0.8 mm, the space between the lower surface of the flange 12 and the surface of the aluminum sheet 10 will be too small, resulting in insufficient space for the engaging part 21 of the lower plastic 20 to engage, causing assembly difficulties or interference with the surface of the aluminum sheet 10. If the height H3 from the flange 12 to the surface of the aluminum sheet 10 is greater than 5 mm, the height H2 of the side wall 112 will increase accordingly, affecting stamping and local rigidity.

[0122] The difference between the height H2 of the sidewall 112 of the through hole 11 and the height H3 of the flange 12 to the surface of the aluminum sheet 10, i.e. the height of the flange 12 (H2-H3), is equal to the wall thickness ((CB) / 2) of the opening 111 along the diameter direction, i.e., satisfying: 0.5mm≤(CB) / 2=H2-H3≤1.5mm.

[0123] The height (H2-H3) of the flange 12 represents the height of the portion of the side wall 112 used to guide the engaging part 21 into place and provide support. The height (H2-H3) of the flange 12 is greater than or equal to 0.5 mm to ensure lateral support and improve the stability of the connection.

[0124] The radial wall thickness ((CB) / 2) of the opening 111 is between 0.5mm and 1.5mm, and is one of 0.5mm, 0.7mm, 1mm, 1.2mm and 1.5mm, so that the flange 12 has sufficient strength to withstand the bending moment brought by the clamping force, which is conducive to the realization of the stamping flange 12 process.

[0125] In one embodiment, the outer diameter of the flange 12 is D, and the outer diameter D of the flange 12 and the outer diameter C of the opening 111 satisfy: 0.5mm≤(DC) / 2≤1.5mm.

[0126] The outer diameter D of the flange 12 is the diameter of the annular flange 12 at its outermost edge. (DC) / 2 is the radial extension of the annular flange 12 from the annular sidewall 112 along the first direction, which is the radial length of the flange 12. Further, the radial length (DC) / 2 of the flange 12 is one of 0.5mm, 0.7mm, 1mm, 1.2mm, and 1.5mm.

[0127] If the radial extension of the flange 12 is less than 0.5mm, the length of the flange 12 is too small, resulting in a small contact surface with the engaging part 21, leading to unstable engagement and easy generation of local contact stress, causing local plastic deformation or wear. If the radial extension of the flange 12 is greater than 1.5mm, the excessively large flange 12 will occupy the space of the aluminum sheet 10, affecting the layout of other components.

[0128] In one embodiment, the height H1 of the countersunk hole 13, the height H2 of the sidewall 112 of the through hole 11, and the height H3 of the flange 12 to the surface of the aluminum sheet 10 satisfy: (C 2 -B 2 )*H3+(D 2 -C 2 ) * (H2 - H3) ≤ 0.8 * A 2 *H1.

[0129] (C²-B²)*H3 can be understood as the volume of the annular sidewall 112. (D²-C²)*(H2-H3) can be understood as the volume of the radially extending portion of the flange 12. Adding the two together, we can understand it as the volume of metal material consumed by the entire protruding flange 12 structure.

[0130] A²*H1 represents the volume of the recessed space formed by the countersunk hole 13. The coefficient 0.8 can be interpreted as allowing the material volume used to form the protrusion to occupy a maximum of 80% of the volume provided by the countersunk hole 13. This means that during stamping, the material used to form the protruding structure is provided by the countersunk hole 13 area formed by the recess on the back side. A 20% allowance, i.e., coefficient 0.8, ensures that the protruding structure maintains sufficient thickness after forming, preventing breakage due to excessive stretching.

[0131] In this embodiment, an aluminum alloy sheet 10 with a thickness or total height H of 1.0 mm is used. The countersunk hole 13 has a diameter A of 10 mm, a height H1 of 0.5 mm, an inner diameter B of the opening 111 of the through hole 11 of 8 mm, an outer diameter of the opening 111 of 9 mm, an outer diameter D of the annular flange 12 of 10.4 mm, a height H2 of the sidewall 112 of the through hole 11 of ...

[0132] Where A = 10.0 mm, the relationship 5 mm ≤ A ≤ 15 mm is satisfied.

[0133] (CB) / 2=H2-H3=(9-8) / 2=0.5mm, which satisfies the relationship 0.8mm≤H3<5mm and 0.5mm≤(CB) / 2=H2-H3≤1.5mm.

[0134] (DC) / 2 = (10.4-9) / 2 = 0.7mm, which satisfies the relationship 0.5mm ≤ (DC) / 2 ≤ 1.5mm.

[0135] H / 3≈0.33mm, 2H / 3≈0.67mm, satisfying the relationship H / 3≤H1≤2H / 3.

[0136] (C²-B²)*H3=(9²-8²)*1.5=(81-64)*1.5=17*1.5=25.5mm³.

[0137] (D 2 -C 2 )*(H2-H3)=(10.4 2 -9 2 )*0.5=(108.16-81)*0.5=27.16*0.5=13.58mm³.

[0138] The approximate volume of material required for the protrusion is 25.5 + 13.58 = 39.08 mm³.

[0139] The usable material volume for countersunk hole 13 is 80% of 0.8*A²*H1=0.8*10²*0.5=0.8*100*0.5=40mm³.

[0140] It can be seen that 39.08mm³≤40mm³, which satisfies the inequality.

[0141] Combination Figure 8 As shown, Figure 8 This is a schematic flowchart illustrating a method for preparing a battery cell 100 according to one embodiment of this application. In one embodiment, a method for preparing the battery cell 100 is also provided, comprising the following steps:

[0142] Step S1: The aluminum sheet 10 is stamped to form at least one protruding through hole 11;

[0143] Step S2: Stretch the through hole 11 to form a flange 12 extending in the first direction;

[0144] Step S3: Snap the engaging part 21 on the lower plastic 20 onto the flange 12.

[0145] In step S1, a stamping die is used to perform a punching or drawing process on the aluminum sheet 10 blank. The stamping die includes a punch or punch for the upper die and a die or die plate for the lower die.

[0146] Under the action of the press, the punch moves downward and closes with the die, causing localized plastic deformation of the aluminum sheet 10 blank. The material is squeezed into the die cavity, forming a cylindrical boss that protrudes towards the lower plastic 20 and is closed at the bottom. This boss is the prototype of the through hole 11, and the height of the boss provides the base material for subsequent stretching and flanging 12.

[0147] In step S2, the boss is further axially stretched using a stretching punch that matches the shape of the boss's inner cavity. The height of the boss's sidewall 112 increases, forming an annular sidewall 112. At this point, the through hole 11 has transformed from a boss with a closed bottom into a cylindrical portion with an opening 111.

[0148] After stretching, the end 113 of the cylindrical part is flanged 12. Typically, a flanging mold 12 with a cavity of a specific angle is used. A slider or wedge mechanism that can move laterally, i.e. in the first direction, is used to apply radial force to the end 113 of the cylindrical part from the inside or outside, so that the material bends and extends outward to form the flanging 12.

[0149] In step S3, a pre-molded lower plastic 20 is provided, which has a recess 22 corresponding to the position of the through hole 11 of the aluminum sheet 10, a mounting hole 23, and a locking part 21. Under pressure, the locking part 21 of the lower plastic 20, i.e., the hook 211, contacts the first surface 121 of the flange 12, causing the hook 211 to deform. As the pressing continues, the hook 211 passes the highest point of the flange 12, and the plane on the hook 211 forms a plane contact with the second surface 122 of the flange 12, thereby achieving mechanical interlocking and restricting the lower plastic 20 to the aluminum sheet 10.

[0150] The raised flange 12 structure, formed by stamping, stretching, and flanging 12 processes, avoids the deep hole dead angles produced by the traditional cold heading countersinking 13 process. The open geometry allows metal shavings or oil stains to be thoroughly washed away in subsequent cleaning processes, improving the cleanliness of the top cover assembly 101. At the same time, replacing the two complex processes of traditional cold heading and hot melting with continuous stamping formation results in high efficiency and low cost; press fitting does not require heating, thereby saving energy, simplifying the production process, and reducing manufacturing costs.

[0151] In one embodiment, step S2, which involves stretching the through hole 11, further includes the following step:

[0152] Step S21: The end 113 of the through hole 11 is stamped to form an inwardly recessed opening 111;

[0153] Step S22: Stretch the circumferential sidewall 112 of the opening 111;

[0154] Step S23: Flanging the sidewall 112 to form a ring-shaped flange 12.

[0155] In step S21, the punch partially presses the inner edge of the end 113 of the protruding through hole 11 to form a recess facing the aluminum sheet 10. The opening 111 can reduce the weight of the protruding through hole 11 and the flange 12 structure, thereby reducing the overall weight of the top cover assembly 101, achieving weight reduction, and saving costs.

[0156] In step S22, the stretching punch moves downward, pulling the sidewall 112 material with the recessed opening 111 further to increase the height of the sidewall 112 so as to form the flange 12.

[0157] In step S23, when the forming slider moves laterally, its cavity covers and acts on the end 113 of the sidewall 112, causing the material of the end 113 to bend outward and fit into the cavity, forming a composite curved surface with a first surface 121 having a guiding function and a second surface 122 for horizontal bearing.

[0158] The above-mentioned steps of preforming the opening 111 and sidewall 112, stretching the sidewall 112, and then performing the flanging 12 process reduce the risk of edge cracking or excessive thinning of the flanging 12, thereby ensuring structural integrity and fatigue life.

[0159] In one embodiment, a battery device is also provided, comprising a plurality of battery cells 100 as described above or battery cells 100 prepared by the above-described method for preparing battery cells 100. The battery device includes one or more of the following: battery module, battery pack, and energy storage battery.

[0160] The battery cell 100 can be used, but is not limited to, in electrical devices or energy storage devices such as vehicles, ships, or aircraft. The aforementioned battery cell 100, battery devices, etc., can be used to form a power system for an electrical device or energy storage device, improving the stability of battery performance and battery life.

[0161] In one embodiment, an electrical device is also provided, including the battery device described above, which provides electrical energy. The electrical device is, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, etc. The electric toys may include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys.

[0162] In one embodiment, an energy storage device is also provided, including the battery device described above, which is used to store electrical energy. The energy storage device is, but is not limited to, an energy storage container, an energy storage cabinet, an energy storage power station, an energy storage battery pack, or a portable energy storage system.

[0163] With the deepening of energy structure transformation, the demand for long-term energy storage systems of 4 hours or even more than 8 hours is increasing. These systems typically use high-capacity batteries for large-scale integration. By adopting the battery modules and energy storage systems that provide 100 battery cells, the reliability of battery use can be improved, meeting the needs of high-capacity batteries for long-term, deep-cycle charge and discharge, which helps to build high-capacity battery energy storage systems for 4-hour, 8-hour, and even longer periods of energy storage.

[0164] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0165] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A battery cell, comprising an electrode assembly and a top cover assembly, characterized in that, The top cover assembly includes an aluminum sheet and a lower plastic sheet, wherein the lower plastic sheet is disposed on the side of the aluminum sheet facing the electrode assembly; The aluminum sheet includes at least one through hole protruding toward the lower plastic side, and the circumferential sidewall of the through hole is provided with an outwardly extending flange. The lower plastic includes at least one engaging portion protruding toward one side of the aluminum sheet, the engaging portion engaging with the flange.

2. The battery cell of claim 1, wherein, The through hole includes an opening, which is formed by a recess at the end of the through hole facing the side of the aluminum sheet.

3. The battery cell of claim 2, wherein, The flange extends outward from the circumferential sidewall of the through hole along a first direction.

4. The battery cell according to claim 2, characterized in that, The through hole has an annular structure, and the sidewall of the through hole extends from the aluminum sheet along the second direction toward the lower plastic side. The flange is connected to the end of the opening.

5. The battery cell according to claim 4, characterized in that, The flange is an annular flange circumferentially arranged around the side wall of the annular through hole.

6. The battery cell according to claim 4, characterized in that, The lower plastic includes a settling tank, and the settling tank is provided with a mounting hole that mates with the through hole. The mounting hole is an annular hole that penetrates the lower plastic.

7. The battery cell according to claim 6, characterized in that, The engaging part includes a hook, one end of which is disposed on the side wall of the mounting hole, and the other end extends along a first direction. The surface of the hook that contacts the flange is a plane.

8. The battery cell according to claim 5, characterized in that, The annular flange includes a first surface and a second surface. The first surface is disposed at the end of the opening, and there is an angle between the first surface and the plane containing the end of the opening. The second surface is connected to the first surface and is disposed parallel to the first direction.

9. The battery cell according to claim 2, characterized in that, The surface of the aluminum sheet away from the lower plastic is provided with at least one inwardly recessed countersunk hole, which is located above the through hole.

10. The battery cell according to claim 9, characterized in that, The diameter of the countersunk hole is A, and the diameter A of the countersunk hole satisfies: 5mm≤A≤15mm; The height of the aluminum sheet is H, and the height of the countersunk hole is H1. The height H of the aluminum sheet and the height H1 of the countersunk hole satisfy: H / 3≤H1≤2H / 3.

11. The battery cell according to claim 10, characterized in that, The height of the sidewall of the through hole is H2, the height of the flange to the surface of the aluminum sheet is H3, the inner diameter of the opening is B, and the outer diameter of the opening is C. The height H3 of the flange to the surface of the aluminum sheet satisfies: 0.8mm≤H3<5mm; the height H2 of the sidewall of the through hole and the height H3 of the flange to the surface of the aluminum sheet satisfy: 0.5mm≤(CB) / 2=H2-H3≤1.5mm.

12. The battery cell according to claim 11, characterized in that, The outer diameter of the flange is D, and the outer diameter D of the flange and the outer diameter C of the opening satisfy: 0.5mm≤(DC) / 2≤1.5mm.

13. The battery cell according to claim 12, characterized in that, The height H1 of the counterbore, the height H2 of the side wall of the through hole, and the height H3 of the turn to the surface of the aluminum sheet satisfy: (C 2 -B 2 ) * H3 + (D 2 -C 2 ) * (H2-H3) ≤ 0.8 * A 2 * H1.

14. A method for preparing a single battery cell, characterized in that, include: The aluminum sheet is stamped to form at least one raised through hole; The through hole is stretched to form a flange extending in the first direction; The snap-fit ​​part on the lower plastic is snapped onto the flange.

15. The method for preparing a battery cell according to claim 14, characterized in that, The step of stretching the through hole further includes: The end of the through hole is stamped to form an inwardly recessed opening; The circumferential sidewalls of the opening are stretched. The sidewalls are flanged to form a circular flange.

16. A battery device, characterized in that, The battery device includes multiple battery cells as described in any one of claims 1-13, and the battery device includes one or more of battery modules, battery packs, and energy storage batteries.

17. An electrical appliance, characterized in that, Includes the battery device as described in claim 16, the battery device being used to provide electrical energy.

18. An energy storage device, characterized in that, Including the battery device as described in claim 16, The battery device is used to store electrical energy.

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