Preparation method of cover plate assembly, cover plate assembly and battery cell

Abstract

The invention provides a preparation method of a cover plate assembly, the cover plate assembly and a battery cell, and the method comprises the following steps: a trepanning step: providing a plate, and forming a through hole in the plate; the through hole penetrates through the first face and the second face of the plate in the first direction. A punching step: extruding the edge of the through hole from the second surface to the first surface so as to form a cylindrical bulge protruding out of the first surface; the cylindrical protrusion comprises a cylindrical inner wall, a cylindrical outer wall and an annular end face. Material splitting preparation is conducted, specifically, an annular first mold is arranged on the outer side of the cylindrical protrusion in a sleeving mode and abuts against the first face, and the first mold and the cylindrical outer wall are spaced from each other; and material splitting is conducted, specifically, the part, close to the cylindrical inner wall, of the cylindrical protrusion is stamped through a second die in the direction from the annular end face to the second face so as to form a second fixing part, the part, close to the cylindrical outer wall, of the cylindrical protrusion moves towards the first die so as to avoid the second die, and a first fixing part is formed. The preparation method of the cover plate assembly, the cover plate assembly and the battery cell provided by the invention have better safety performance.

Description

[0001] This application claims priority to Chinese Patent Application No. 202510596516.5, filed in China on May 9, 2025, entitled "Cover Assembly, Cell and Battery Pack", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, and in particular to a method for preparing a cover plate assembly, the cover plate assembly, and a battery cell. Background Technology

[0003] In the development of battery technology, besides improving cell performance, safety is also a crucial issue that cannot be ignored. If the safety of the cells cannot be guaranteed, then the cells cannot be used. Therefore, how to enhance cell safety is a pressing technical problem that needs to be solved in battery technology. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a method for manufacturing a cover plate assembly, the cover plate assembly, and a battery cell, so as to at least partially solve the problem of how to enhance the safety of the battery cell.

[0005] To achieve the above objectives, the first aspect of this application provides a method for manufacturing a cover plate assembly, comprising: Hole-making step: Provide a sheet material and form a through hole in the sheet material; the through hole penetrates through a first surface and a second surface of the sheet material along a first direction; the first direction is the thickness direction of the sheet material; Punching step: The edge of the through hole is pressed from the second surface to the first surface to form a cylindrical protrusion protruding from the first surface; the cylindrical protrusion includes a cylindrical inner wall, a cylindrical outer wall, and an annular end face connected to the cylindrical inner wall and the cylindrical outer wall respectively; Material preparation steps: The annular first mold is fitted onto the outside of the cylindrical protrusion and abuts against the first surface, with the first mold and the outer wall of the cylindrical shape spaced apart from each other; Splitting step: The second mold is used to punch the portion of the cylindrical protrusion near the inner wall of the cylindrical shape from the direction of the annular end face to the second face to form a second fixing part. The portion of the cylindrical protrusion near the outer wall of the cylindrical shape moves toward the first mold to avoid the second mold and forms a first fixing part.

[0006] Optionally, in the splitting preparation step, along the second direction, the minimum straight-line interval between the first mold and the outer wall of the cylindrical shape is L1, and the second direction is perpendicular to the first direction; on the same side of the center line of the cylindrical protrusion, the straight-line interval between the inner edge and the outer edge of the annular end face along the second direction is L; the ratio of L1 to L is greater than 0 and less than or equal to 0.06.

[0007] Optionally, the inner wall of the first mold is inclined relative to the root of the cylindrical protrusion in the first direction, and the inclination angle is a, where 0° < a ≤ 10°.

[0008] Optionally, the end face of the first mold abuts against the first surface, and a first rounded corner is provided between the inner wall of the first mold and the end face, and the radius of the first rounded corner is R, where 0 < R ≤ 2 mm.

[0009] Optionally, on the same side of the centerline of the cylindrical protrusion, the linear interval between the inner and outer edges of the annular end face along the second direction is L, and the maximum linear interval between the outer edge of the projection of the second mold onto the annular end face along the first direction and the outer edge of the annular end face along the second direction is L2, with the ratio of L2 to L being 0.5 to 0.6; the second direction is perpendicular to the first direction.

[0010] Optionally, the splitting step includes: During the stamping process, a stepped portion is formed at the connection between the inner wall of the first fixing part and the inner wall of the second fixing part.

[0011] Optionally, the splitting step further includes: When stamping the portion of the cylindrical protrusion near the inner wall of the cylindrical protrusion, the position of the second surface surrounding the cylindrical protrusion is supported to form a groove on the second surface.

[0012] Optionally, in the punching step, a second rounded corner is formed between the cylindrical inner wall and the second surface; After the punching step and before the splitting step, the following steps are also included: In the material preparation step, a portion of the annular third mold is fitted onto the outside of the cylindrical protrusion, spaced apart from the outer wall of the cylindrical shape, to form a space for the cylindrical protrusion to deform; the other portion of the third mold abuts against the annular end face. In the blanking step, the second mold is used to press the annular end face toward the second surface to reduce the radius of the second rounded corner.

[0013] Optionally, the splitting step includes: When stamping the portion of the cylindrical protrusion near the inner wall of the cylindrical shape, a first anti-torsion structure is formed on the inner surface of the first fixing part.

[0014] Optionally, the first fixing portion includes a first end remote from the plate; the method for manufacturing the cover plate assembly further includes: The first end is pressed toward the second surface to form a first anti-torsion structure on the inner surface of the first fixing part.

[0015] Optionally, the splitting step includes: An anti-torsion groove is formed on the stepped portion.

[0016] Optionally, the punching step includes: The edge of the through hole is punched at least twice from the second surface toward the first surface, so that the diameter of the through hole increases gradually and forms a cylindrical protrusion protruding from the first surface.

[0017] Optionally, the first fixing part includes a first end remote from the plate; the method for manufacturing the cover plate assembly further includes: The first end is pressed toward the second surface so that the first end bends toward the center line of the first fixing part.

[0018] Optionally, the first fixing portion and the second fixing portion define an accommodating space; the method for manufacturing the cover plate assembly further includes: The pole with the sealing part is fixed in the receiving space.

[0019] Based on the same inventive concept, a second aspect of this application provides a cover plate assembly, which is formed by the method for preparing a cover plate assembly as described in the first aspect. The cover plate assembly includes: a cover plate, the cover plate including a cover plate body made of at least a portion of a sheet metal and a first fixing portion, and a receiving space formed by a through hole; the first fixing portion includes a first sub-part extending along a first direction, the first sub-part including a first root portion and a second root portion disposed along a second direction, the first root portion being closer to the receiving space than the second root portion, the first root portion being integrally formed and connected to the cover plate body, and the second root portion being discontinuously disposed to the cover plate body and abutting against a first surface; the second direction is perpendicular to the first direction.

[0020] Optionally, on one side of the centerline of the receiving space, the minimum dimension of the end of the first sub-part away from the cover body along the second direction is: L4 The sum of the dimensions of the first root and the second root along the second direction is L3, where L3 > L4.

[0021] Optionally, the outer wall of the first sub-part is inclined relative to the centerline of the receiving space in the first direction.

[0022] Optionally, the first sub-part satisfies at least one of the following conditions: The inner wall of the first sub-part is parallel to the first direction; The inclination angle of the outer wall of the first sub-part is b, where 0° < b ≤ 10°.

[0023] Optionally, on one side of the centerline of the accommodating space, the straight-line distance between the inner and outer edges of the first root along the second direction is L5, and the ratio of L5 to L3 is greater than 0.65.

[0024] Optionally, the cover plate further includes a second fixing part, the second fixing part including a second inner wall; the second inner wall satisfies at least one of the following conditions: The second inner wall is perpendicular to the first direction; Along the first direction, the straight-line distance between the second inner wall and the first surface is H1, where 1mm ≤ H1 ≤ 1.3mm.

[0025] Optionally, the thickness of the cover plate body is H3; the cover plate body satisfies at least one of the following conditions: The first fixing part includes a second sub-part, which is integrally formed and connected to the first sub-part and extends along the second direction toward the center line of the receiving space. The dimension of the second sub-part along the first direction is H2, and the ratio of H2 to H3 is 0.14 to 0.48. The cover plate further includes a second fixing part, the second fixing part having a dimension of H4 along the first direction, and the ratio of H4 to H3 being 0.15 to 0.5.

[0026] Optionally, the cover plate further includes a second fixing part, the first fixing part includes a first inner wall, the second fixing part includes a second inner wall, the first inner wall and the second inner wall and the step part connecting the first inner wall and the second inner wall form the receiving space, and the step part protrudes from the second inner wall in the direction of the first surface.

[0027] Optionally, the second surface is provided with a groove surrounding the second fixing portion, and the groove extends to the second fixing portion along the second direction.

[0028] Optionally, the stepped portion is connected to the first inner wall to form an inner connecting portion; along the first direction, the projection of the inner connecting portion on the second surface is located within the groove.

[0029] Optionally, it includes an electrode post and an insulating sealing structure, wherein the electrode post and the insulating sealing structure are at least partially placed within the receiving space, and the cover plate and the electrode post are connected through the insulating sealing structure; the insulating sealing structure includes an upper insulating portion and a sealing portion.

[0030] Optionally, at least one of the first fixing part, the pole post, and the step part is provided with an anti-torsion structure; The anti-torsion structure provided in the first fixing part is a first anti-torsion structure, and the upper insulating part is formed with a first insulating anti-torsion structure; one of the first anti-torsion structure and the first insulating anti-torsion structure is a recessed groove structure, and the other is a protrusion structure fitted into the groove structure. The anti-torsion structure provided on the pole post is a second anti-torsion structure, and the upper insulating part is formed with a second insulating anti-torsion structure; one of the second anti-torsion structure and the second insulating anti-torsion structure is a groove structure, and the other is a protrusion structure fitted into the groove structure; The step portion is provided with an anti-torsion structure, which is an anti-torsion groove, and the upper insulating portion is formed with a third insulating anti-torsion structure; the third insulating anti-torsion structure is fitted into the anti-torsion groove.

[0031] Based on the same inventive concept, a third aspect of this application provides a battery cell, including a housing, an electrode assembly, and a cover assembly as described in the second aspect, wherein the cover assembly is connected to the housing, and the electrode assembly is disposed within the space formed by the cover assembly and the housing.

[0032] As can be seen from the above, the method for preparing the cover plate assembly, the cover plate assembly, and the battery cell provided in this application can construct a cover plate with a cover plate body, a first fixing part, and a second fixing part from a flat plate through the steps of opening a hole, punching a hole, and splitting the material. Since the cover plate body, the first fixing part, and the second fixing part are integrally formed and connected, it helps to improve the connection strength between the three and helps to reduce the risk of breakage at the connection between the first fixing part and the cover plate body, and at the connection between the second fixing part and the cover plate body.

[0033] Meanwhile, when forming the first fixing part, the first mold fitted on the outside of the cylindrical protrusion is spaced apart from the outer wall of the cylindrical protrusion, which can provide sufficient outward deformation space for the part of the cylindrical protrusion near the outer wall of the cylindrical protrusion, so that the material of this part can move toward the first mold in the splitting step, thereby effectively avoiding the second mold, so that the second mold can move smoothly in the first direction. This is conducive to the first fixing part and the second fixing part being formed according to the preset structure, and thus the first fixing part after forming can reliably fix the electrode post, which helps to improve the connection reliability of the electrode post and the cover plate, as well as the safety of the battery cell. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a partial cross-sectional schematic diagram of the battery cell of the first structure according to an embodiment of this application; Figure 2 This is a partial top view of the cover plate assembly of the second structure according to an embodiment of this application; Figure 3 for Figure 2 Schematic diagram of the cross section AA; Figure 4 for Figure 3 Enlarged schematic diagram of part B in the middle; Figure 5 This is a schematic flowchart of a method for preparing a cover plate assembly according to an embodiment of this application; Figure 6a This is a partial cross-sectional schematic diagram of the opening step in the preparation method of the cover plate assembly with the third structure according to an embodiment of this application; Figure 6b This is a cross-sectional view of the method for preparing a cover plate assembly with a third structure according to an embodiment of this application, in which the plate is first extruded to form a cylindrical protrusion during the punching step. Figure 6c This is a cross-sectional view of the method for preparing a cover plate assembly with a third structure according to an embodiment of this application, in which the plate is extruded for the second time in the punching step to form a cylindrical protrusion. Figure 6d This is a partial cross-sectional schematic diagram of the material preparation step in the method for preparing the cover plate assembly of the third structure according to an embodiment of this application. Figure 6e This is a partial cross-sectional schematic diagram of the material-pressing step in the preparation method of the cover plate assembly with the third structure according to an embodiment of this application; Figure 6f This is a partial cross-sectional schematic diagram of the material preparation step in the method for preparing the cover plate assembly of the third structure according to an embodiment of this application. Figure 6g This is a partial cross-sectional view showing the completion of the first splitting step in the preparation method of the cover plate assembly with the third structure according to an embodiment of this application; Figure 6h This is a partial cross-sectional view of the first splitting step in the preparation method of the cover plate assembly of the third structure according to an embodiment of this application. Figure 6i This is a partial cross-sectional schematic diagram of the method for preparing the cover plate assembly of the third structure according to an embodiment of this application, which forms the first anti-torsion structure. Figure 6j This is a partial cross-sectional schematic diagram of the second splitting step in the preparation method of the cover plate assembly with the third structure according to an embodiment of this application; Figure 6k This is a partial cross-sectional view of the first end during the first extrusion in the preparation method of the cover plate assembly of the third structure in this application embodiment; Figure 6l This is a partial cross-sectional view of the first end during the second extrusion in the preparation method of the cover plate assembly of the third structure in this application embodiment; Figure 6m This is a partial cross-sectional view of the first end during the final extrusion in the preparation method of the cover plate assembly of the third structure in this application embodiment; Figure 6n This is a partial cross-sectional schematic diagram of the method for preparing a cover plate assembly with a pole post in the third structure of this application embodiment; Figure 7 The cover plate assembly of the third structure in the embodiments of this application is in Figure 5 Enlarged schematic diagram of part B in the middle; Figure 8 for Figure 7 An enlarged schematic diagram of section C; Figure 8a for Figure 8 An enlarged schematic diagram of section D in the middle; Figure 9 The cover plate assembly of the fourth structure in the embodiments of this application is in Figure 7 An enlarged schematic diagram of section C; Figure 10 This is a schematic diagram of the cover plate of the cover plate assembly with the fifth structure according to an embodiment of this application; Figure 11 This is a schematic diagram of a battery cell according to an embodiment of this application.

[0036] Explanation of reference numerals in the attached figures: 1000, Cover plate assembly; 100. Cover plate; 110. Cover plate body; 111. Groove; 112. First surface; 113. Second surface; 114. Mounting hole; 120. First fixing part; 121. First inner wall; 122. First end; 123. First sub-section; 124a. First root; 124b. Second root; 125. Second sub-section; 130. Second fixing part; 131. Second inner wall; 140. Accommodation space; 150. Step section; 200. Pole post; 210. Pole post body; 220. Protrusion; 230. Pole post base plate; 300, lower insulating component; 400, upper insulating component; 500, riveting block; 600, sealing ring; 700. Insulating and sealing structure; 710. Sealing part; 720. Upper insulating part; 721. First insulating anti-torsion structure; 722. Second insulating anti-torsion structure; 723. Third insulating anti-torsion structure; 730. Lower insulating part; 800, Anti-torsion structure; 810, First anti-torsion structure; 820, Second anti-torsion structure; 830, Anti-torsion groove; 2000, housing; 2100, open end; 3000, Electrode Assembly; 4000, Plate; 4100, Through hole; 4200, Cylindrical protrusion; 4210, Cylindrical inner wall; 4220, Cylindrical outer wall; 4230, Second fillet; 4240, Annular end face; 5000, Hole-expanding die; 6000, Third die; 7000, Annular extrusion die; 8000, Second mold; 8000a, First mold; 8100, First fillet; 9000, Bending die; 9100, Conical surface; 10000, Circular limiting mold; 11000, Anti-torsion forming mold. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0038] It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components described in these embodiments do not limit the scope of this application.

[0039] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0040] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0041] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0042] Figure 1 A partial cross-sectional schematic diagram of the first type of battery cell is shown.

[0043] like Figure 1 In some embodiments, the battery cell includes a cover assembly 1000 and a housing 2000. The cover assembly 1000 includes a cover body 110, which is provided with a portion along its thickness direction (e.g., ...). Figure 1 A mounting hole 114 (in the Z direction) is provided, and the cover plate body 110 is fitted and connected to the opening end 2100 of the housing 2000, so that the cover plate body 110 and the housing 2000 enclose a space for accommodating the electrode assembly 3000. A lower insulating member 300 is connected to the side of the cover plate body 110 near the electrode assembly 3000, and an upper insulating member 400 is connected to the side of the cover plate body 110 away from the electrode assembly 3000. The cover plate assembly 1000 also includes a pole post 200, which is fitted with a sealing ring 600 and passes through the lower insulating member 300, the cover plate body 110, and the upper insulating member 400. The end of the pole post 200 away from the electrode assembly 3000 extends out of the upper insulating member 400 and is riveted to the riveting block 500. The pole post 200 and the cover plate body 110 press the sealing ring 600 to seal the pole post 200 and the cover plate body 110 through the sealing ring 600, and to insulate the pole post 200 and the cover plate body 110 through the upper insulating member 400 and the lower insulating member 300.

[0044] As can be seen from the foregoing, in order to achieve an insulated and sealed connection between the pole post 200 and the cover plate body 110 in this embodiment, at least a lower insulating component 300, a sealing ring 600, an upper insulating component 400, and a riveting block 500 are required. This results in a large number of components and high material costs. Furthermore, the assembly of the pole post 200 to the cover plate body 110 requires bonding (e.g., connecting the lower insulating component 300 to the cover plate body 110) and riveting (e.g., connecting the riveting block 500 to the pole post 200), making the assembly process complex and inefficient.

[0045] To address the aforementioned issues, embodiments of this application provide cover plate assemblies 1000 with alternative structures.

[0046] Figure 2 A partial top view of the cover plate assembly 1000 with the second structure is shown. Figure 3 Showing Figure 2 A schematic diagram of the cross-section AA in the middle. Figure 4 Showing Figure 3 Enlarged schematic diagram of part B.

[0047] like Figure 2 and Figure 3In some embodiments, the cover plate assembly 1000 includes a cover plate 100, a terminal post 200, and an insulating sealing structure 700, wherein the cover plate 100 and the terminal post 200 are connected via the insulating sealing structure 700. Exemplarily, the terminal post 200 may include a positive terminal post and a negative terminal post. The positive terminal post is used to electrically connect to the positive tab of the electrode assembly 3000 (the positive tab is formed by the current collector extending outward from the positive electrode sheet of the electrode assembly 3000) to form the positive electrode of the battery cell, and the negative terminal post is used to electrically connect to the negative tab of the electrode assembly 3000 (the negative tab is formed by the current collector extending outward from the negative electrode sheet of the electrode assembly 3000) to form the negative electrode of the battery cell.

[0048] like Figure 3 and Figure 4 The cover plate 100 includes a cover plate body 110, a first fixing part 120, and a second fixing part 130. The first fixing part 120 and the second fixing part 130 are arranged around the pole post 200. The cover plate body 110 includes a first fixing part along a first direction (e.g., Figure 4 A first surface 112 and a second surface 113 are arranged opposite to each other (in the Z direction). A first fixing part 120 extends from the first surface 112 at least along a first direction away from the cover plate body 110, and a second fixing part 130 extends from the second surface 113 at least along a second direction (e.g., in the Z direction). Figure 4 The first fixing part 120 and the second fixing part 130 extend toward the center line of the pole post 200 in the X direction. The first fixing part 120 and the second fixing part 130 define the receiving space 140. The pole post 200 and the insulating sealing structure 700 are at least partially located in the receiving space 140. The first direction is the center line direction of the pole post 200, and the second direction is perpendicular to the first direction.

[0049] For example, when the cover assembly 1000 is applied to the cell, the second side 113 is close to the electrode assembly 3000.

[0050] For example, the insulating sealing structure 700 includes a lower insulating portion 730 connected to the side of the cover plate 100 near the second surface 113.

[0051] For example, the first fixing part 120, the second fixing part 130 and the cover plate body 110 can be integrally formed and connected; or, the first fixing part 120 and the second fixing part 130 can be integrally formed and connected and welded to the cover plate body 110.

[0052] It should be noted that the first fixing part 120 extends from the first surface 112 at least along the first direction away from the cover plate body 110, which does not mean that the end of the first fixing part 120 near the cover plate body 110 is disposed on the first surface 112. It simply means that the first fixing part 120 extends out of the cover plate body 110 from the first surface 112, and the first fixing part 120 may also extend between the first surface 112 and the second surface 113. Similarly, the second fixing part 130 extends from the second surface 113 at least along the second direction towards the center line of the pole post 200, which also does not mean that the end of the second fixing part 130 near the cover plate body 110 is disposed on the second surface 113. The second fixing part 130 may also extend between the first surface 112 and the second surface 113.

[0053] contrast Figure 1 and Figure 4 It can be known that Figure 1 In the structure shown, the middle part of the pole post 200 is columnar, and its lower end needs to be connected to a pole post base plate 230 with a large horizontal area. The pole post base plate 230 and the riveting block 500 cooperate to clamp the upper insulating component 400, the sealing ring 600, the cover plate body 110 and the lower insulating component 300, forming a stable pole post assembly. However, because the pole post 200 needs to be equipped with a pole post base plate 230 and connected to the riveting block 500, this results in a large amount of metal material used in the cover plate assembly 1000, higher material costs, and a larger overall weight of the cover plate assembly 1000.

[0054] Figure 4 In the structure shown, the pole post 200 is generally columnar, the second fixing part 130 supports the pole post 200, and the insulating sealing structure 700 allows for a reliable connection between the pole post 200 and the first fixing part 120. Compared to Figure 1 The structure shown eliminates the pole base plate 230 and the rivet block 500, reducing the amount of metal material used in the cover plate assembly 1000, which helps to reduce the assembly difficulty and material cost of the cover plate assembly 1000.

[0055] The applicant's research found that during the process of forming the first fixing part 120 by die stamping, if the die and the material to be formed are too tightly fitted, the material to be formed will not have enough space to avoid the die during the die stamping process, which will cause the moving die to get stuck. The first fixing part 120 will have difficulty forming the preset structure, and the first fixing part 120 will also have difficulty reliably fixing the pole post 200. This will result in low connection reliability between the pole post 200 and the cover plate 100, which will also have an adverse effect on the safety of the battery cell.

[0056] To address the aforementioned issues, this embodiment provides a method for preparing the cover plate assembly 1000.

[0057] Figure 5A flowchart illustrating the fabrication method of the cover plate assembly 1000 with the third structure is shown. Figure 6a A partial cross-sectional schematic diagram showing the opening step of the fabrication method of the cover plate assembly 1000 with the third structure is shown. Figure 6b A partial cross-sectional view showing the fabrication method of the cover plate assembly 1000 of the third structure, in which the sheet metal 4000 is first extruded in the punching step to form a cylindrical protrusion 4200; Figure 6c A partial cross-sectional view showing the fabrication method of the cover plate assembly 1000 of the third structure, in which the sheet metal 4000 is extruded a second time in the punching step to form a cylindrical protrusion 4200; Figure 6d A partial cross-sectional schematic diagram showing the material preparation steps of the fabrication method for the cover plate assembly 1000 of the third structure; Figure 6e A partial cross-sectional schematic diagram showing the fabrication process of the cover plate assembly 1000 with the third structure; Figure 6f A partial cross-sectional schematic diagram showing the material preparation steps of the fabrication method for the cover plate assembly 1000 of the third structure; Figure 6g A partial cross-sectional view showing the fabrication method of the cover plate assembly 1000 with the third structure after the completion of the first splitting step; Figure 6h A partial cross-sectional view showing the first splitting step in the fabrication method of the cover plate assembly 1000 with the third structure; Figure 6i A partial cross-sectional schematic diagram of the formation of the first anti-torsion structure 810, which shows the manufacturing method of the cover plate assembly 1000 with the third structure; Figure 6j A partial cross-sectional schematic diagram illustrating the second splitting step of the fabrication method for the cover plate assembly 1000 with the third structure; Figure 6k A partial cross-sectional view of the first end 122 during the first extrusion in the manufacturing method of the cover plate assembly 1000 of the third structure is shown. Figure 6l A partial cross-sectional view of the first end 122 during the second extrusion in the fabrication method of the cover plate assembly 1000 of the third structure is shown. Figure 6m A partial cross-sectional view of the first end 122 during the final extrusion in the fabrication method of the cover plate assembly 1000 of the third structure is shown. Figure 6n A partial cross-sectional schematic diagram of the assembly of the pole post 200 onto the cover plate 100 is shown in the preparation method of the cover plate assembly 1000 of the third structure.

[0058] like Figure 5 The method for preparing the cover plate assembly 1000 provided in this embodiment includes: like Figure 6a S100, Hole-making step: Provide a sheet material 4000, and form a through hole 4100 on the sheet material 4000; the through hole 4100 is along a first direction (e.g., Figure 6aThe Z-direction penetrates the first surface 112 and the second surface 113 of the plate 4000; the first direction is the thickness direction of the plate 4000.

[0059] It should be noted that the first surface 112 and the second surface 113 are two surfaces of the plate 4000 that are arranged opposite to each other along its thickness direction. At least a portion of the plate 4000 between the first surface 112 and the second surface 113 is used to form the cover plate body 110.

[0060] Through holes 4100 are formed on the sheet metal 4000 by means of drilling, punching or milling. The through holes 4100 are used to form a receiving space 140.

[0061] like Figure 6a , Figure 6b and Figure 6c S200, punching step: the edge of the through hole 4100 is pressed from the second surface 113 toward the first surface 112 to form a cylindrical protrusion 4200 protruding from the first surface 112; the cylindrical protrusion 4200 includes a cylindrical inner wall 4210, a cylindrical outer wall 4220, and an annular end face 4240 connected to the cylindrical inner wall 4210 and the cylindrical outer wall 4220 respectively.

[0062] It should be noted that both the cylindrical inner wall 4210 and the cylindrical outer wall 4220 are arranged around the center line of the cylindrical protrusion 4200, and the annular end face 4240 is the end face of the cylindrical protrusion 4200 that is away from the second surface 113 along the thickness direction of the plate 4000.

[0063] The wall of the through hole 4100 is pressed towards the first surface 112, causing the pressed portion of the plate 4000 to bulge towards the first surface 112, forming a cylindrical protrusion 4200 protruding from the first surface 112. At the same time, the diameter of the through hole 4100 also increases accordingly.

[0064] The cylindrical protrusion 4200 is the structural basis for forming the first fixing part 120 and the second fixing part 130.

[0065] like Figure 6c and Figure 6f S300, Material preparation steps: The annular first mold 8000a is fitted onto the outside of the cylindrical protrusion 4200 and abuts against the first surface 112. The first mold 8000a and the cylindrical outer wall 4220 are spaced apart from each other.

[0066] like Figure 6g and Figure 6hS400, Splitting step: The second mold 8000 punches the part of the cylindrical protrusion 4200 near the inner wall 4210 of the cylindrical shape from the annular end face 4240 toward the second face 113 to form the second fixing part 130. The part of the cylindrical protrusion 4200 near the outer wall 4220 of the cylindrical shape moves toward the first mold 8000a to avoid the second mold 8000 and forms the first fixing part 120.

[0067] It should be noted that both the first fixing part 120 and the second fixing part 130 are arranged around the center line of the through hole 4100.

[0068] When splitting the cylindrical protrusion 4200, the first mold 8000a and the second mold 8000 are used in conjunction. The first mold 8000a is fitted onto the outside of the cylindrical protrusion 4200 and abuts against the first surface 112, thereby positioning the second mold 8000 and the cylindrical protrusion 4200. At least a portion of the second mold 8000 slides within the first mold 8000a along a first direction to stamp the portion of the cylindrical protrusion 4200 near the inner cylindrical wall 4210. The second mold 8000 can be a columnar structure, the outer diameter of which is larger than the inner diameter of the cylindrical protrusion 4200 and smaller than the outer diameter of the cylindrical protrusion 4200.

[0069] like Figure 6h and Figure 6g After the bottom end of the second mold 8000 abuts against the annular end face 4240, pressure is applied to the portion of the annular end face 4240 near the cylindrical inner wall 4210 to push the portion of the cylindrical protrusion 4200 near the cylindrical inner wall 4210 downward and change its shape until it forms a second fixing part 130 that is at least partially an annular flat plate structure.

[0070] like Figure 6h Although the portion of the cylindrical protrusion 4200 near the outer wall 4220 is not directly pressed by the second mold 8000, it is still subjected to a downward force due to the pressure on the pressed portion. Since the first mold 8000a and the outer wall 4220 are spaced apart, space can be provided for the portion of the cylindrical protrusion 4200 near the outer wall 4220 to deform outward. After deforming outward, this portion can avoid the second mold 8000, allowing the second mold 8000 to move smoothly along the first direction, achieving high-quality stamping of the cylindrical protrusion 4200, which is beneficial for the first fixing part 120 and the second fixing part 130 to be formed according to the preset structure.

[0071] The method for manufacturing the cover plate assembly 1000 provided in this embodiment, through a hole-opening step, a punching step, and a splitting step, can construct a cover plate 100 having a cover plate body 110, a first fixing part 120, and a second fixing part 130 from a flat plate 4000. Since the cover plate body 110, the first fixing part 120, and the second fixing part 130 are integrally formed and connected, it helps to improve the connection strength between the three and helps to reduce the risk of breakage at the connection between the first fixing part 120 and the cover plate body 110, and at the connection between the second fixing part 130 and the cover plate body 110.

[0072] Meanwhile, when forming the first fixing part 120, the first mold 8000a, which is fitted on the outside of the cylindrical protrusion 4200, is spaced apart from the cylindrical outer wall 4220. This provides sufficient space for the part of the cylindrical protrusion 4200 near the cylindrical outer wall 4220 to deform outward, so that the material in this part can move toward the first mold 8000a during the splitting step, thereby effectively avoiding the second mold 8000. This allows the second mold 8000 to move smoothly in the first direction, which is beneficial for the first fixing part 120 and the second fixing part 130 to be formed according to the preset structure. As a result, the first fixing part 120 after forming can reliably fix the electrode post 200, which helps to improve the connection reliability of the electrode post 200 and the cover plate 100, as well as the safety of the battery cell.

[0073] like Figure 6f In some embodiments, during the splitting preparation step, along the second direction (e.g.) Figure 6f The minimum straight-line interval between the first mold 8000a and the cylindrical outer wall 4220 is L1, and the second direction is perpendicular to the first direction; on the same side of the center line of the cylindrical protrusion 4200, the straight-line interval between the inner edge and the outer edge of the annular end face 4240 along the second direction is L; the ratio of L1 to L is greater than 0 and less than or equal to 0.06.

[0074] It should be noted that when at least one of the cylindrical outer wall 4220 and the inner wall of the first mold 8000a (i.e., the surface of the first mold 8000a facing the cylindrical protrusion 4200) is inclined relative to the first direction, the straight-line interval distance between each region of the cylindrical outer wall 4220 and the inner wall of the first mold 8000a along the first direction is not the same, and L1 is the minimum value among them.

[0075] For example, the ratio of L1 to L can be 0.01, 0.015, 0.02, 0.025, 0.03, 0.035, 0.04, 0.045, 0.05, 0.055 or 0.06.

[0076] If the ratio of L1 to L is too large, the gap between the first mold 8000a and the second mold 8000 along the second direction will be too large. When the second mold 8000 stamps the cylindrical protrusion 4200, the portion used to form the first fixing part 120 may undergo uncontrolled deformation within the excessively large space, leading to problems such as excessive bending of the first fixing part 120. If the ratio of L1 to L is too small, the gap between the first mold 8000a and the second mold 8000 along the second direction will be insufficient, and the aforementioned problem of obstructed movement of the second mold 8000 may still occur.

[0077] To avoid the above problems, this embodiment designs the ratio of L1 to L to be greater than 0 and less than or equal to 0.06, which can make the part of the cylindrical protrusion 4200 near the cylindrical outer wall 4220 deform in a suitable space, so as to avoid the second mold 8000 and ensure that the first fixing part 120 is formed according to the preset structure.

[0078] like Figure 6f In some embodiments, the inner wall of the first mold 8000a is inclined relative to the root of the cylindrical protrusion 4200 in the first direction, and the inclination angle is α, where 0° < α ≤ 10°. For example, 'a' can be 0.5°, 1°, 1.5°, 2°, 2.5°, 3°, 3.5°, 4°, 4.5°, 5°, 5.5°, 6°, 6.5°, 7°, 7.5°, 8°, 8.5°, 9°, 9.5°, or 10°.

[0079] If 'a' is too large, it may result in the top thickness of the first fixing part 120 after molding being too small, and the structural strength of the top of the first fixing part 120 being low. If the top of the first fixing part 120 breaks, it will have an adverse effect on the connection reliability of the pole post 200 and the cover plate 100.

[0080] To avoid the above problems, this embodiment designs a to be 0°<a≤10°, which can ensure that the thickness of the root of the first fixing part 120 after molding is large, and that the top of it has sufficient thickness, so that the first fixing part 120 as a whole has high structural strength.

[0081] At the same time, the inclined inner wall of the first mold 8000a also facilitates the separation of the first mold 8000a from the first fixed part 120 after molding, that is, it facilitates demolding.

[0082] like Figure 6f In some embodiments, the end face of the first mold 8000a abuts against the first surface 112, and a first fillet 8100 is provided between the inner wall of the first mold 8000a and the end face, and the radius of the first fillet 8100 is R, where 0 < R ≤ 2 mm.

[0083] For example, R can be 0.3mm, 0.5mm, 0.8mm, 1mm, 1.3mm, 1.5mm, 1.8mm or 2mm.

[0084] The problems caused by an excessively large R are similar to those caused by an excessively large L1, and will not be repeated here.

[0085] In this embodiment, R is designed to be 0 < R ≤ 2 mm, which allows the root of the cylindrical protrusion 4200 to deform within a suitable space to form the first fixing part 120 according to the preset structure. This helps to improve the structural strength and connection reliability of the connection between the first fixing part 120 and the cover plate body 110. At the same time, the first rounded corner 8100 can also make the outer wall of the first fixing part 120 and the first surface 112 arc transition, which helps to avoid stress concentration at the root of the first fixing part 120 and further reduces the risk of cracking at the connection between the first fixing part 120 and the cover plate body 110.

[0086] like Figure 6g and Figure 6f In some embodiments, the maximum linear distance between the outer edge of the projection of the second mold 8000 onto the annular end face 4240 along the first direction and the outer edge of the annular end face 4240 along the second direction is L2, and the ratio of L2 to L is 0.5 to 0.6; the second direction is perpendicular to the first direction.

[0087] It should be noted that the outer edge of the projection of the second mold 8000 can be circular, or a protruding protrusion or an inwardly recessed groove can be provided in a circular part. The outer edge of the annular end face 4240 is circular. This results in different regions of the outer edge of the projection of the second mold 8000 along the circumference of the annular end face 4240 having different linear intervals in the second direction between each region and the outer edge of the annular end face 4240, with L2 being the maximum value.

[0088] For example, the ratio of L2 to L can be 0.5, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59 or 0.6.

[0089] Understandably, the portion between the outer edge of the projection of the second mold 8000 and the outer edge of the annular end face 4240 will not be directly stamped by the second mold 8000. The corresponding cylindrical protrusion 4200 is used to form the first fixing part 120. If the ratio of L2 to L is too large, the thickness of the material used to form the first fixing part 120 will be too large. During the splitting step, this part of the material will not easily deform outward, and thus cannot effectively avoid the second mold 8000, which may cause difficulties in forming the first fixing part 120. If the ratio of L2 to L is too small, the thickness of the material used to form the first fixing part 120 will be too small. The resulting first fixing part 120 will have low structural strength due to insufficient material, and will not be able to effectively fix the pole post 200.

[0090] To avoid the above problems, this embodiment designs the ratio of L2 to L to be 0.5 to 0.6. In the splitting step, it can ensure that there is enough material reserved for the first fixing part 120, which helps to improve the structural strength of the first fixing part 120. It can also ensure that the material used to form the first fixing part 120 can effectively avoid the second mold 8000, so that the first fixing part 120 can be formed smoothly.

[0091] like Figure 6g In some embodiments, the S400 splitting step includes: During the stamping process, a stepped portion 150 is formed at the connection between the inner wall of the first fixing portion 120 and the inner wall of the second fixing portion 130.

[0092] It should be noted that the stepped portion 150 is continuously or intermittently arranged around the center line of the through hole 4100.

[0093] like Figure 6g The bottom of the second mold 8000 has an inwardly recessed groove structure, which can shape the pressure-moving part of the cylindrical protrusion 4200 to form the stepped part 150.

[0094] Combination Figure 6g The structure and orientation shown are illustrated by way of example. If the step portion 150 is not formed between the inner walls of the first fixing part 120 and the second fixing part 130, then the inner walls of the first fixing part 120 and the second fixing part 130 will intersect and form a right-angle structure. However, when the step portion 150 is formed between the inner walls of the first fixing part 120 and the second fixing part 130, compared to the right-angle structure, sufficient material can be ensured at the connection between the first fixing part 120 and the second fixing part 130, which can effectively prevent breakage between the first fixing part 120, the second fixing part 130 and the cover plate body 110, and help improve the reliability of the connection between the three.

[0095] like Figure 6gIn some embodiments, the S400 splitting step includes: When stamping the portion of the cylindrical protrusion 4200 near the inner wall 4210 of the cylindrical protrusion, the second surface 113 is supported around the cylindrical protrusion 4200 to form a groove 111 on the second surface 113.

[0096] Before the splitting step, an annular extrusion die 7000 can be set on the second surface 113, with the center line of the annular extrusion die 7000 coinciding with the center line of the cylindrical protrusion 4200. The annular extrusion die 7000 supports the position of the second surface 113 around the cylindrical protrusion 4200. During the process of the second die 8000 pressing the cylindrical protrusion 4200 downwards from the annular end face 4240, the annular extrusion die 7000 uses the downward pressure on the plate 4000 at the bottom of the plate to reverse-extrude the second surface 113. The portion of the annular extrusion die 7000 that contacts the second surface 113 forms a recessed groove 111. The original material in the groove 111 is squeezed to the first connection point (i.e., the connection between the first fixing part 120 and the cover plate body 110), the second connection point (i.e., the connection between the second fixing part 130 and the cover plate body 110), and the step portion 150, ensuring sufficient material at these three locations and greater structural strength.

[0097] It should be noted that when the second fixing part 130 protrudes from the second surface 113, the annular extrusion die 7000 can also limit the outer diameter of the second fixing part 130 so that the second fixing part 130 protruding from the second surface 113 is located inside the cylindrical outer wall 4220 of the cylindrical protrusion 4200.

[0098] like Figure 6c , 6d and Figure 6e In some embodiments, during the punching step, a second fillet 4230 is formed between the cylindrical inner wall 4210 and the second surface 113; After the punching step and before the splitting step, it also includes: S500, Material preparation step: A portion of the annular third mold 6000 is fitted onto the outside of the cylindrical protrusion 4200, and spaced apart from the cylindrical outer wall 4220 to form a space for the cylindrical protrusion 4200 to deform; another portion of the third mold 6000 abuts against the annular end face 4240.

[0099] S600, the pressing step, uses the third mold 6000 to press the annular end face 4240 towards the second surface 113 to reduce the radius of the second fillet 4230.

[0100] It should be noted that the thickness of the cylindrical protrusion 4200 is, that is, the dimension of the cylindrical protrusion 4200 along the second direction on one side of the centerline of the cylindrical protrusion 4200.

[0101] like Figure 6d The third mold 6000 has an inverted L-shaped cross-section on one side of the center line of the cylindrical protrusion 4200. Its vertically extending part is fitted onto the outside of the cylindrical protrusion 4200, and its horizontally extending part abuts against the annular end face 4240.

[0102] Understandably, after the cylindrical protrusion 4200 is formed, the second surface 113 naturally bends with the cylindrical inner wall 4210 of the cylindrical protrusion 4200 to form the second rounded corner 4230. However, the applicant has found that when the radius of the second rounded corner 4230 is large, there is less material at the second rounded corner 4230, which may lead to a shortage of material in the second fixing part 130 when it is subsequently formed.

[0103] To avoid the aforementioned problems, this embodiment uses an annular pressing die 6000 to press the annular end face 4240, causing the material to fill the second rounded corner 4230, and the radius of the second rounded corner 4230 is correspondingly reduced. This helps to improve the structural strength of the second fixing part 130 and also helps to improve the connection strength between the plate 4000 and the second fixing part 130, preventing breakage at the connection.

[0104] During the extrusion process described above, the outer diameter of the cylindrical protrusion 4200 tends to expand. If the third mold 6000 is in close contact with the outer wall 4220 of the cylindrical protrusion during the material preparation step, the third mold 6000 will constrain the outer diameter of the cylindrical protrusion 4200. As a result, the cylindrical protrusion 4200 can only expand outwards to the portion between the third mold 6000 and the first surface 112. This may hinder the movement of the third mold 6000 and make it difficult to reduce the radius of the second fillet 4230 to the preset size.

[0105] To avoid the aforementioned problems, this embodiment designs the third mold 6000 and the cylindrical outer wall 4220 to be spaced apart from each other, forming a space for the cylindrical protrusion 4200 to deform. In this way, when the cylindrical protrusion 4200 is squeezed by the third mold 6000, it can expand its outer diameter more evenly to release the squeezing pressure, effectively reducing the risk of deformation of the cylindrical protrusion 4200 in the space between the third mold 6000 and the first surface 112, and ensuring that the third mold 6000 can smoothly press the cylindrical protrusion 4200 to reduce the radius of the second fillet 4230 to a preset size.

[0106] Meanwhile, in order to avoid uncontrollable deformation of the second surface 113 and the cylindrical inner wall 4210 when extruding the annular end face 4240, a mold that supports the second surface 113 and fits against the cylindrical inner wall 4210 can be set during the extrusion process. The surface of the mold that fits against the cylindrical inner wall 4210 and the surface that supports the second surface 113 transition at a right angle. On the one hand, this prevents the inner diameter of the cylindrical protrusion 4200 from changing, and on the other hand, it can shape the material filling the second rounded corner 4230 to reduce the radius of the second rounded corner 4230.

[0107] like Figure 6j In some embodiments, the S400 splitting step includes: An anti-torsion groove 830 is formed on the step portion 150.

[0108] The second mold 8000 can also have protruding structures in some areas of the groove structure for forming the stepped portion 150. When the second mold 8000 extrudes the portion of the cylindrical protrusion 4200 near the inner wall 4210 of the cylindrical protrusion, the protruding structures in the groove structure can extrude a portion of the stepped portion 150. The extruded material shrinks or moves downward to form a recessed anti-torsion groove 830 in a portion of the stepped portion 150.

[0109] like Figure 6f and Figure 6j In some embodiments, the S400 splitting step includes: When stamping the portion of the cylindrical protrusion 4200 near the inner wall 4210 of the cylindrical shape, a first anti-torsion structure 810 is formed on the inner surface of the first fixing part 120.

[0110] Figure 6j Taking the first anti-torsion structure 810 as an example of a groove structure, the second mold 8000 can also be provided with a protruding structure on its circumferential sidewall. When the second mold 8000 extrudes the part of the cylindrical protrusion 4200 near the cylindrical inner wall 4210, the structure protruding from the circumferential sidewall of the second mold 8000 can extrude the unpressurized first fixing part 120. The extruded part of the material shrinks or moves downward to form a groove structure as the first anti-torsion structure 810 on the inner surface of the first fixing part 120.

[0111] In this embodiment, the second fixing part 130, the first fixing part 120, the step part 150, the groove 111, the first anti-torsion structure 810 and the anti-torsion groove 830 can be completed simultaneously, which helps to simplify the manufacturing process of the cover plate 100, reduce the manufacturing cost and improve the manufacturing efficiency.

[0112] Of course, in addition to the above-mentioned method of forming the first anti-torsion structure 810, the first fixing part 120 and the first anti-torsion structure 810 can also be formed in steps.

[0113] Specifically, such as Figure 6g and Figure 6i In some embodiments, the first fixing portion 120 includes a first end 122 located away from the plate 4000; the method of manufacturing the cover plate assembly 1000 further includes: The first end 122 is pressed toward the second surface 113 to form a first anti-torsion structure 810 on the inner surface of the first fixing part 120.

[0114] like Figure 6g When forming the first fixing part 120, the inner surface of the first fixing part 120 can be a cylindrical surface. For example... Figure 6i Then, the first fixing part 120 is extruded by the anti-torsion forming mold 11000. The circumferential surface of the cylindrical body of the anti-torsion forming mold 11000 is attached to the inner surface of the first fixing part 120. A protruding structure is formed on the circumferential surface of the cylindrical body. The protruding structure is used to extrude the first end 122 to form a groove structure as the first anti-torsion structure 810 on the inner surface of the first fixing part 120.

[0115] It should be noted that when the first anti-torsion structure 810 is a protrusion, a portion of the first end 122 can be squeezed by a mold, and the unsqueezed portion forms a protrusion as the first anti-torsion structure 810.

[0116] like Figure 6a , Figure 6b and Figure 6c In some embodiments, the S200 punching step includes: The edge of the through hole 4100 is punched at least twice from the second surface 113 toward the first surface 112, so that the diameter of the through hole 4100 increases gradually and forms a cylindrical protrusion 4200 protruding from the first surface 112.

[0117] Specifically, such as Figure 6b First, a hole-expanding mold 5000 with an outer diameter slightly larger than the current through-hole 4100 is inserted into the through-hole 4100 through the second surface 113, pressing the hole wall of the through-hole 4100 to make the compressed part of the plate 4000 bulge towards the first surface 112. At the same time, the diameter of the through-hole 4100 also increases under the action of the hole-expanding mold 5000.

[0118] When the expanding die 5000 extrudes the sheet 4000, an annular limiting die 10000 can be set on the first surface 112 around the through hole 4100. The annular limiting die 10000 can limit the outer edge of the part that protrudes towards the first surface 112 to prevent the part from bending outward.

[0119] like Figure 6cA larger-diameter enlarging mold 5000 is used, inserted into the through hole 4100 that has already been enlarged once through the second surface 113, and the hole wall of the through hole 4100 is squeezed again, so that the compressed part of the plate 4000 continues to bulge towards the first surface 112. At the same time, the outer diameter of the bulging part and the diameter of the through hole 4100 also become larger.

[0120] The above operation can be repeated multiple times using a reaming mold 5000 with a gradually increasing outer diameter until the raised portion forms a cylindrical protrusion 4200 whose outer and inner diameters both meet the preset dimensions. This cylindrical protrusion 4200 extends along the thickness direction of the plate 4000 from the plate 4000 in a direction away from the first surface 112.

[0121] like Figure 6k , Figure 6l and Figure 6m In some embodiments, the first fixing portion 120 includes a first end 122 remote from the plate 4000; the method of manufacturing the cover plate assembly 1000 further includes: The first end 122 is pressed toward the second surface 113 so that the first end 122 bends toward the center line of the first fixing part 120.

[0122] like Figure 6k For the cylindrical first fixing part 120, the first end 122 is first squeezed by the bending die 9000. The bending die 9000 has a conical surface 9100. During the first squeeze, the angle β between the conical surface 9100 and the vertical direction is small, so that the vertical first end 122 is squeezed towards the center line of the first fixing part 120 under the pressure of the conical surface 9100.

[0123] like Figure 6l For the first fixed part 120 that has been squeezed once, a bending die 9000 with a conical surface 9100 having a large β angle can be used to continue squeezing the first end 122, so that the first end 122 is further gathered and tilted under the squeezing action of the conical surface 9100.

[0124] After repeated compressions as described above, Figure 6m Finally, the first fixing part 120 can be squeezed by a flat mold so that the part of the first fixing part 120 near the first end 122 bends toward the center line of the first fixing part 120.

[0125] like Figure 6n In some embodiments, the first fixing portion 120 and the second fixing portion 130 define a receiving space 140; the method of manufacturing the cover assembly 1000 further includes: The pole post 200, which is fitted with the sealing part 710, is fixed in the receiving space 140.

[0126] After the cover plate 100 is formed, the pole post 200 with the sealing part 710 can be inserted into the receiving space 140. The second fixing part 130 will limit part of the structure of the pole post 200 to prevent the pole post 200 from coming out of the receiving space 140.

[0127] Based on the same inventive concept and in conjunction with the description of the preparation method of the cover plate assembly 1000 in the above embodiments, this embodiment provides a cover plate assembly 1000, which has the corresponding technical effects of the preparation method of the cover plate assembly 1000 in the above embodiments, and will not be repeated here.

[0128] Figure 7 The third type of cover plate assembly 1000 was demonstrated. Figure 3 An enlarged diagram of part B in the middle. Figure 8 Showing Figure 7 An enlarged diagram of section C. Figure 8a Showing Figure 8 An enlarged schematic diagram of part D in the middle.

[0129] like Figure 6a , Figure 7 , Figure 8 and Figure 8a The cover plate assembly 1000 provided in this embodiment is formed by the preparation method of the cover plate assembly 1000 as described in the above embodiments. The cover plate assembly 1000 includes: a cover plate 100, the cover plate 100 including a cover plate body 110 and a first fixing part 120 formed by at least a portion of the plate 4000, and a receiving space 140 formed by a through hole 4100; the first fixing part 120 includes a first fixing part along a first direction (e.g., Figure 7 The first sub-part 123 extends along the Z direction (as in the second direction), the first sub-part 123 including a second sub-part extending along the Z direction (as in the second direction). Figure 7 The first root 124a and the second root 124b are arranged in the X direction. The first root 124a is closer to the receiving space 140 than the second root 124b. The first root 124a is integrally formed and connected to the cover plate body 110. The second root 124b is discontinuously arranged with the cover plate body 110 and abuts against the first surface 112. The second direction is perpendicular to the first direction.

[0130] It should be noted that the first sub-part 123 is the portion of the first fixing part 120 that extends along the first direction; that is, the first fixing part 120 is located in... Figure 6m The part that has not been bent.

[0131] In conjunction with the foregoing, during the pressing and splitting steps, when the cylindrical protrusion 4200 is pressed downward by the second mold 8000 (i.e., from the annular end face 4240 towards the second surface 113), the portion of the cylindrical protrusion 4200 integrally formed and connected to the cover plate body 110 will not translate outward along the second direction (i.e., towards the first mold 8000a). After the pressing is completed, this portion forms the first root 124a of the first sub-part 123. The portion of the cylindrical protrusion 4200 near the root will be flipped towards the first surface 112 under the constraint of the cover plate body 110 until it fits against the first surface 112. However, this portion will not be integrated with the cover plate body 110. The two present a stacked structure, which is discontinuous. After the pressing is completed, this portion forms the second root 124b of the first sub-part 123.

[0132] After stamping, the first root 124a is closer to the receiving space 140, that is, the first root 124a is closer to the inner wall of the first sub-part 123, and the second root 124b is closer to the outer wall of the first sub-part 123.

[0133] like Figure 7 , Figure 8 and Figure 8a In some embodiments, on one side of the centerline of the receiving space 140, the dimension of the end of the first sub-part 123 away from the cover body 110 along the second direction is L4, and the sum of the dimensions of the first root part 124a and the second root part 124b along the second direction is L3, where L3 > L4.

[0134] Understandably, since the first root portion 124a is integrally formed and connected to the cover plate body 110, the two can form an effective connection. However, the second root portion 122a is discontinuously disposed with the cover plate body 110, so the two cannot form an effective connection. Therefore, only by ensuring that the first root portion 124a has a relatively sufficient thickness (i.e., the dimension along the second direction on one side of the centerline of the accommodating space 140) can the first fixing portion 120 be reliably connected to the cover plate body 110.

[0135] The thickness of the first root 124a is at most equal to L4. Therefore, in this embodiment, L3 is designed to be greater than L4, which takes into account the thickness of the second root 124b. This ensures that even if the second root 124b exists, the first root 124a can still have a relatively sufficient thickness to ensure that the first fixing part 120 and the cover plate body 110 have high structural strength and connection reliability.

[0136] like Figure 8 and Figure 8a In some embodiments, the outer wall of the first sub-part 123 is inclined relative to the centerline of the receiving space 140 in the first direction.

[0137] Based on the foregoing, it can be understood that the inner wall of the first mold 8000a is inclined. Therefore, during the process of forming the first fixing part 120 through the first mold 8000a, the outer wall of the first fixing part 120 will be formed to have the same structure as the inner wall of the first mold 8000a, that is, the outer wall of the first sub-part 123 is inclined.

[0138] like Figure 8 In some embodiments, the inner wall of the first sub-part 123 is parallel to the first direction.

[0139] In light of the foregoing, if the inner wall of the first sub-part 123 is designed to be inclined, it may hinder the movement of the second mold 8000 along the first direction during the splitting process, causing inconvenience.

[0140] To avoid the above problems, in this embodiment, the inner wall of the first sub-part 123 is designed to be parallel to the first direction, thereby ensuring that the second mold 8000 can move smoothly along the first direction during the splitting step.

[0141] like Figure 8 In some embodiments, the inclination angle of the outer wall of the first sub-part 123 is b, where 0° < b ≤ 10°.

[0142] Based on the foregoing, it can be seen that the outer wall of the first sub-part 123 is modeled after the inner wall of the first mold 8000a, so the inclination angles of the two are similar.

[0143] It should be noted that after the first mold 8000a separates from the first fixing part 120, the outer wall of the first sub-part 123 may spring back. Therefore, the tilt angle of the outer wall of the first sub-part 123 may be different from the tilt angle of the inner wall of the first mold 8000a.

[0144] like Figure 8 and Figure 8a In some embodiments, on one side of the centerline of the accommodating space 140, the straight-line distance between the inner and outer edges of the first root 124a along the second direction is L5, and the ratio of L5 to L3 is greater than 0.65.

[0145] For example, the ratio of L5 to L3 can be 0.65, 0.7, 0.75, 0.8, 0.85 or 0.9.

[0146] For example, L5 > 0.65 mm.

[0147] Based on the foregoing, if the thickness of the first root portion 124a is too small, the connection reliability between the first fixing portion 120 and the cover plate body 110 will be poor.

[0148] To avoid the above problems, this embodiment designs the ratio of L5 to L3 to be greater than 0.65 to ensure that the first root 124a has sufficient thickness, thereby effectively improving its structural strength and the connection reliability between the first fixing part 120 and the cover plate body 110.

[0149] like Figure 8 In some embodiments, the cover plate 100 further includes a second fixing part 130, which includes a second inner wall 131; the second inner wall 131 is perpendicular to the first direction.

[0150] As can be seen from the foregoing, the second fixing part 130 supports the sealing part 710. When the second inner wall 131 of the second fixing part 130 is perpendicular to the first direction, the second inner wall 131 is a plane, which can more stably and reliably support the sealing part 710. During the assembly and use of the cover plate assembly 1000, the sealing part 710 can be kept flat, which helps to ensure that the sealing part 710 has a better sealing effect.

[0151] Meanwhile, the second inner wall 131, designed as a plane, can more stably and reliably support the pole post 200. During mass production, it can make the exposed height of the pole post 200 relative to the first surface 112 consistent, which helps to improve the consistency of the cover plate assembly 1000.

[0152] like Figure 8 In some embodiments, along the first direction, the straight-line distance between the second inner wall 131 and the first surface 112 is H1, where 1mm≤H1≤1.3mm.

[0153] For example, H1 can be 1mm, 1.1mm, 1.2mm or 1.3mm.

[0154] If H1 is too large, the second fixing part 130 will protrude too far from the second surface 113, occupying too much space in the cell for accommodating the electrode assembly 3000, resulting in a lower energy density of the cell. If H1 is too small, the terminal post 200 will protrude too far from the first surface 112, occupying too much space in the battery pack when the cells are assembled, thus resulting in a lower energy density of the battery pack.

[0155] To avoid the above problems, in this embodiment, H1 is designed to be 1mm≤H1≤1.3mm, which can ensure that the cells using the cover plate assembly 1000 of this embodiment have a high energy density, and also ensure that the battery pack constructed from the cells has a high energy density.

[0156] like Figure 8In some embodiments, the first fixing part 120 includes a second sub-part 125, which is integrally formed and connected to the first sub-part 123 and extends along the second direction toward the center line of the receiving space 140; the thickness of the cover body 110 is H3; the dimension of the second sub-part 125 along the first direction is H2, and the ratio of H2 to H3 is 0.14 to 0.48.

[0157] It should be noted that the second sub-part 125 is... Figure 6m The part of the first fixing part 120 that is bent.

[0158] For example, the ratio of H2 to H3 can be 0.14, 0.18, 0.2, 0.24, 0.28, 0.3, 0.34, 0.38, 0.4, 0.44 or 0.48.

[0159] For example, H2 can be 0.7mm to 0.9mm, such as 0.7mm, 0.8mm or 0.9mm.

[0160] If the ratio of H2 to H3 is too large, the thickness of the second sub-part 125 will be too large. During injection molding of the upper insulating part 720, which includes the first fixing part 120, the second sub-part 125 will occupy too much space in the injection mold cavity and be too close to the inner wall of the mold cavity. This will result in the portion of the upper insulating part 720 covering the first fixing part 120 being too thin, leading to lower structural strength and a higher risk of cracking. If the ratio of H2 to H3 is too small, the thickness of the second sub-part 125 will be too small, resulting in lower structural strength and making it difficult to reliably limit and fix the pole post 200.

[0161] To avoid the aforementioned problems, this embodiment designs the ratio of H2 to H3 to be between 0.14 and 0.48. This ensures that the second sub-part 125 of the first fixing part 120 has sufficient thickness, which helps to improve its structural strength. At least the second sub-part 125 can limit the position of the pole post 200 installed in the receiving space 140, so that the cover plate 100 and the pole post 200 can be reliably connected. At the same time, it also ensures that the upper insulating part 720 covering the first fixing part 120 also has sufficient thickness, effectively preventing cracking and other problems in the upper insulating part 720, helping to ensure the insulation performance of the upper insulating part 720 and improving the safety performance of the battery cell.

[0162] like Figure 8 In some embodiments, the second fixing part 130 has a dimension of H4 along the first direction, and the ratio of H4 to H3 is 0.15 to 0.5.

[0163] For example, the ratio of H4 to H3 can be 0.15, 0.18, 0.2, 0.24, 0.28, 0.3, 0.34, 0.38, 0.4, 0.44, 0.48 or 0.5.

[0164] For example, H4 can be 0.8mm to 1mm, such as 0.8mm, 0.9mm or 1mm.

[0165] If the ratio of H4 to H3 is too large, the thickness of the second fixing part 130 will be too small, resulting in low structural strength. This increases the risk of cracks appearing at the second connection. On one hand, the second fixing part 130 will struggle to effectively limit the pole post 200; on the other hand, it may bend and deform under pressure, making it difficult to effectively compress the sealing part 710. This will lead to poor sealing performance of the sealing part 710 and negatively impact the sealing performance of the cover assembly 1000. Conversely, if the ratio of H4 to H3 is too large, the thickness of the first fixing part 120 will be too small, resulting in low structural strength. This also increases the risk of cracks appearing at the first connection, making it difficult for the first fixing part 120 to effectively fix the pole post 200.

[0166] To avoid the above problems, this embodiment designs the ratio of H4 to H3 to be 0.15 to 0.5, which can ensure that the first fixing part 120 and the second fixing part 130 have greater structural strength. This not only provides better limiting and fixing for the pole post 200, but also effectively compresses the sealing part 710, ensuring that the sealing effect of the sealing part 710 is stable and reliable, and helps to improve the sealing performance of the cover plate assembly 1000.

[0167] like Figure 7 and Figure 8 In some embodiments, the cover plate 100 further includes a second fixing part 130, the first fixing part 120 includes a first inner wall 121, the second fixing part 130 includes a second inner wall 131, the first inner wall 121 and the second inner wall 131 and the step part 150 connecting the first inner wall 121 and the second inner wall 131 form a receiving space 140, and the step part 140 protrudes from the second inner wall 131 in the direction of the first surface 112.

[0168] The beneficial effects of providing a step portion 150 in the cover plate 100 that connects to the first inner wall 121 and the second inner wall 131 are the same as those of providing the step portion 150 mentioned above, and will not be repeated here.

[0169] like Figure 7 and Figure 8 In some embodiments, the second surface 113 is provided with a groove 111 surrounding the second fixing part 130, and the groove 111 extends to the second fixing part 130 along the second direction.

[0170] For example, the groove 111 is an annular groove surrounding the second fixing part 130.

[0171] In conjunction with the foregoing, when forming the cover plate 100, the second surface 113 can be pressed to form a groove 111. After the groove 111 is formed, the material at the original position of the groove 111 will be pressed to move to the adjacent position, thereby improving the structural strength of the adjacent position of the groove 111.

[0172] by Figure 8 Taking the structure and orientation shown as an example, the second fixing part 130 is located on the left side of the groove 111, and the two are adjacent. Therefore, after the groove 111 is formed, the material at the original position of the groove 111 will move to the connection between the second fixing part 130 and the cover plate body 110, thereby helping to improve the structural strength of the connection between the second fixing part 130 and the cover plate body 110 and helping to prevent the connection from breaking.

[0173] like Figure 7 and Figure 8 In some embodiments, along the first direction, the step portion 150 is connected to the first inner wall 121 and forms an inner connecting portion d; along the first direction, the projection of the inner connecting portion d onto the second surface 113 is located within the groove 111.

[0174] Still with Figure 8 Taking the structure and orientation shown as an example, the first fixing part 120 is located above the groove 111, and the two are adjacent. Therefore, after the groove 111 is formed, the material at the original position of the groove 111 will move towards the connection between the first fixing part 120 and the cover plate body 110, thereby helping to improve the structural strength of the connection between the first fixing part 120 and the cover plate body 110 and helping to prevent the connection from breaking.

[0175] like Figure 7 and Figure 8 In some embodiments, the cover plate assembly 1000 includes a pole post 200 and an insulating sealing structure 700, the pole post 200 and the insulating sealing structure 700 being at least partially disposed within the receiving space 140, and the cover plate 100 and the pole post 200 being connected by the insulating sealing structure 700; the insulating sealing structure 700 includes an upper insulating portion 720 and a sealing portion 710.

[0176] It should be noted that the pole post 200 includes a columnar pole post body 210 and a protrusion 220 protruding from the pole post body 210 along a second direction. The protrusion 220 can be arranged around the circumferential sidewall of the pole post body 210, and the circumferential sidewall of the pole post body 210 is arranged around the center line of the pole post 200.

[0177] To ensure that the electrode post 200 can smoothly pass through the inner hole formed by the first fixing part 120 after the first fixing part 120 and the second fixing part 130 are formed, the diameter of the inner hole formed by the first fixing part 120 can be set to be larger than the outer diameter of the protrusion 220. Since the second fixing part 130 needs to limit the electrode post 200 along the first direction, the diameter of the inner hole formed by the second fixing part 130 needs to be designed to be smaller than the outer diameter of the protrusion 220.

[0178] Specifically, such as Figure 8 Along the second direction, the first fixing part 120 is located on the side of the pole post 200 away from the center line of the pole post 200, while the second fixing part 130 needs to spatially overlap with a part of the structure of the pole post 200 (e.g., the protrusion 220) in order to limit the pole post 200. Therefore, along the second direction, the second fixing part 130 can be closer to the center line of the pole post 200 to ensure that the second fixing part 130 can reliably limit the pole post 200, while the first fixing part 120 can be farther from the center line of the pole post 200 to prevent the first fixing part 120 from obstructing the pole post 200 from entering the receiving space 140.

[0179] For example, the sealing part 710 can be fitted onto the pole body 210 of the pole 200 and arranged around the pole body 210.

[0180] For example, the material of the sealing portion 710 may include an elastic insulating material, such as rubber or plastic.

[0181] For example, the upper insulating portion 720 may be injection molded from an insulating material.

[0182] by Figure 8 Taking the structure and orientation shown as an example, the lower surface of the protrusion 220 of the pole post 200 and the second inner wall 131 can cooperate with each other to jointly compress the sealing part 710 located between them, so that this part of the sealing part 710 is deformed under pressure to achieve a sealing effect. After being deformed under pressure, the upper end of the sealing part 710 can extend between the protrusion 220 and the stepped part 150, and the lower end can extend out of the receiving space 140.

[0183] The sealing portion 710 extends between the protrusion 220 and the stepped portion 150, which can increase the contact area between the sealing portion 710 and the inner wall of the receiving space 140, thus helping to improve the sealing performance of the sealing portion 710. The sealing portion 710 can also form an insulating barrier between the protrusion 220 and the stepped portion 150, preventing the protrusion 220 and the stepped portion 150 from contacting each other, thus helping to improve the insulation reliability between the pole post 200 and the cover plate 100.

[0184] Combination Figure 7 and Figure 8It can be seen that most of the electrode post 200 is located within the receiving space 140. A continuous insulating and sealing structure 700 with a certain width (dimension along the second direction) is formed between the electrode post 200 and the inner wall of the receiving space 140. This insulating and sealing structure 700 has strong structural strength, which can ensure a stable and reliable connection between the electrode post 200 and the cover plate 100. It also has insulation properties, which can reliably insulate between the electrode post 200 and the cover plate 100. In addition, it fills the gaps in the receiving space 140 so that the electrolyte in the cell cannot leak out through the receiving space 140, thereby helping to improve the safety of the cell.

[0185] Figure 9 Showing Figure 7 An enlarged schematic diagram of the fourth structure in section C.

[0186] like Figure 8 and Figure 9 In some embodiments, at least one of the first fixing part 120, the pole post 200, and the step part 150 is provided with an anti-torsion structure 800. The specific structure of the anti-torsion structure 800 can be illustrated by the following embodiments.

[0187] The first fixing part 120 is provided with an anti-torsion structure 800, which is a first anti-torsion structure 810, and the upper insulating part 720 is formed with a first insulating anti-torsion structure 721; one of the first anti-torsion structure 810 and the first insulating anti-torsion structure 721 is a groove structure, and the other is a protrusion structure fitted into the groove structure.

[0188] For example, a plurality of first anti-torsion structures 810 are provided and spaced apart around the center line of the receiving space 140.

[0189] For example, the upper insulating portion 720 can be formed by injection molding. During injection molding, if the first anti-torsion structure 810 is a protrusion, the injection molding material wraps around the protrusion and forms a groove structure after curing; if the first anti-torsion structure 810 is a groove structure, the injection molding material fills the groove structure and forms a protrusion after fixation.

[0190] It should be noted that, as Figure 8 The first anti-torsion structure 810 is a groove structure, and the first insulating anti-torsion structure 721 is a protrusion fitted into the groove structure. For example... Figure 9 The first insulating anti-torsion structure 721 is a groove structure, and the first anti-torsion structure 810 is a protrusion fitted into the groove structure.

[0191] When the first anti-torsion structure 810 and the first insulating anti-torsion structure 721 are fitted together, a reliable connection can be formed between the upper insulating part 720 and the first fixing part 120, preventing relative movement or rotation between them. Furthermore, as described above, the pole post 200 is connected to the first fixing part 120 of the cover plate 100 via the upper insulating part 720. Therefore, when the upper insulating part 720 and the first fixing part 120 do not rotate relative to each other, it also helps to achieve a stable connection between the pole post 200 and the cover plate 100, preventing relative torsion between them.

[0192] For the battery cell using the cover plate assembly 1000 of this embodiment, when the battery cell is fixed, the cover plate 100 is also fixed accordingly. Since the pole post 200 and the cover plate 100 can remain relatively stationary under the action of the upper insulating part 720 and will not be relatively twisted, it can be ensured that the pole post 200 can form a reliable connection with the external circuit, and it can also be ensured that the pole post 200 can reliably squeeze the sealing part 710 to prevent the sealing part 710 from failing and avoid leakage of electrolyte inside the battery cell.

[0193] like Figure 8 and Figure 9 In some embodiments, the anti-torsion structure 800 provided on the pole post 200 is a second anti-torsion structure 820, and the upper insulating portion 720 is formed with a second insulating anti-torsion structure 722; one of the second anti-torsion structure 820 and the second insulating anti-torsion structure 722 is a groove structure, and the other is a protrusion structure fitted into the groove structure.

[0194] For example, multiple second anti-torsion structures 820 are provided and are spaced apart around the center line of the pole post 200.

[0195] For example, the upper insulating portion 720 can be formed by injection molding. During injection molding, if the second anti-torsion structure 820 is a protrusion, the injection molding material wraps around the protrusion and forms a groove structure after curing; if the second anti-torsion structure 820 is a groove structure, the injection molding material fills the groove structure and forms a protrusion after fixation.

[0196] It should be noted that, as Figure 8 The second insulating anti-torsion structure 722 is a groove structure, and the second anti-torsion structure 820 is a protrusion fitted into the groove structure. For example... Figure 9 The second anti-torsion structure 820 is a groove structure, and the second insulating anti-torsion structure 722 is a protrusion fitted into the groove structure.

[0197] The beneficial effects of the second anti-torsion structure 820 and the second insulating anti-torsion structure 722 being fitted together are similar to the beneficial effects of the first anti-torsion structure 810 and the first insulating anti-torsion structure 721 being fitted together, and will not be repeated here.

[0198] Figure 10A partial schematic diagram of the cover plate 100 of the fifth type of cover plate assembly 1000 is shown.

[0199] like Figure 9 and Figure 10 In some embodiments, the anti-torsion structure 800 provided on the step portion 150 is an anti-torsion groove 830, and the upper insulating portion 720 is formed with a third insulating anti-torsion structure 723; the third insulating anti-torsion structure 723 is fitted into the anti-torsion groove 830.

[0200] The beneficial effects of the anti-torsion groove 830 being fitted and connected with the third insulating anti-torsion structure 723 are similar to the beneficial effects of the first anti-torsion structure 810 being fitted and connected with the first insulating anti-torsion structure 721, and will not be repeated here.

[0201] Based on the same inventive concept and in conjunction with the description of the cover plate assembly 1000 in the above embodiments, this embodiment provides a battery cell that has the corresponding technical effects of the cover plate assembly 1000 in the above embodiments, which will not be repeated here.

[0202] Figure 11 This is a schematic diagram of a battery cell according to an embodiment of this application.

[0203] like Figure 11 The battery cell includes a housing 2000, an electrode assembly 3000, and a cover assembly 1000 as described in the above embodiments. The cover assembly 1000 is connected to the housing 2000, and the electrode assembly 3000 is disposed within the space formed by the cover assembly 1000 and the housing 2000.

[0204] It should be noted that the end of the pole post 200 of the cover plate assembly 1000 near the electrode assembly 3000 can extend out of the insulating sealing structure 700 (i.e., extend out of the lower insulating part 730) and be exposed in the space where the electrode assembly 3000 is located, so that the pole post 200 and the electrode tab of the electrode assembly 3000 can be electrically connected.

[0205] It should be noted that some embodiments of this application have been described above. Other embodiments are within the scope of the appended claims.

[0206] The various embodiments in this application are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0207] The description in this application is given for illustrative purposes and is not intended to be exhaustive or to limit the application to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of this application and to enable those skilled in the art to understand this application and design various embodiments with various modifications suitable for a particular purpose.

[0208] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application (including the claims) is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of this application as described above, which are not provided in the details for the sake of brevity.

[0209] Although this application has been described in conjunction with specific embodiments thereof, many substitutions, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description.

[0210] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of this application.

Claims

1. A method for preparing a cover plate assembly, characterized in that, include: Opening step: Provide a sheet material and form a through hole in the sheet material; The through hole extends through the first and second surfaces of the plate along a first direction; the first direction is the thickness direction of the plate. Punching step: The edge of the through hole is pressed from the second surface to the first surface to form a cylindrical protrusion protruding from the first surface; the cylindrical protrusion includes a cylindrical inner wall, a cylindrical outer wall, and an annular end face connected to the cylindrical inner wall and the cylindrical outer wall respectively; Material preparation steps: The annular first mold is fitted onto the outside of the cylindrical protrusion and abuts against the first surface, with the first mold and the outer wall of the cylindrical shape spaced apart from each other; Splitting step: The second mold is used to punch the portion of the cylindrical protrusion near the inner wall of the cylindrical shape from the direction of the annular end face to the second face to form a second fixing part. The portion of the cylindrical protrusion near the outer wall of the cylindrical shape moves toward the first mold to avoid the second mold and forms a first fixing part.

2. The method for preparing the cover plate assembly according to claim 1, characterized in that, In the material preparation step, along the second direction, the minimum straight-line interval between the first mold and the outer wall of the cylindrical shape is L1, and the second direction is perpendicular to the first direction; on the same side of the center line of the cylindrical protrusion, the straight-line interval between the inner edge and the outer edge of the annular end face along the second direction is L; the ratio of L1 to L is greater than 0 and less than or equal to 0.

06.

3. The method for preparing the cover plate assembly according to claim 1, characterized in that, The inner wall of the first mold is inclined relative to the root of the cylindrical protrusion in the first direction, and the inclination angle is a, 0°<a≤10°.

4. The method for preparing the cover plate assembly according to claim 1, characterized in that, The end face of the first mold abuts against the first surface, and a first rounded corner is provided between the inner wall of the first mold and the end face, and the radius of the first rounded corner is R, 0 < R ≤ 2 mm.

5. The method for preparing the cover plate assembly according to claim 1, characterized in that, On the same side of the centerline of the cylindrical protrusion, the linear interval between the inner and outer edges of the annular end face along the second direction is L, and the maximum linear interval between the outer edge of the projection of the second mold onto the annular end face along the first direction and the outer edge of the annular end face along the second direction is L2, with the ratio of L2 to L being 0.5 to 0.6; the second direction is perpendicular to the first direction.

6. The method for preparing the cover plate assembly according to claim 1, characterized in that, The splitting step includes: During the stamping process, a stepped portion is formed at the connection between the inner wall of the first fixing part and the inner wall of the second fixing part.

7. The method for preparing the cover plate assembly according to claim 1, characterized in that, The splitting step also includes: When stamping the portion of the cylindrical protrusion near the inner wall of the cylindrical protrusion, the position of the second surface surrounding the cylindrical protrusion is supported to form a groove on the second surface.

8. The method for preparing the cover plate assembly according to claim 1, characterized in that, In the punching step, a second rounded corner is formed between the cylindrical inner wall and the second surface; After the punching step and before the splitting step, the following steps are also included: In the material preparation step, a portion of the annular third mold is fitted onto the outside of the cylindrical protrusion, spaced apart from the outer wall of the cylindrical shape, to form a space for the cylindrical protrusion to deform; the other portion of the third mold abuts against the annular end face. In the blanking step, the second mold is used to press the annular end face toward the second surface to reduce the radius of the second rounded corner.

9. The method for preparing the cover plate assembly according to claim 1, characterized in that, The splitting step includes: When stamping the portion of the cylindrical protrusion near the inner wall of the cylindrical shape, a first anti-torsion structure is formed on the inner surface of the first fixing part.

10. The method for preparing the cover plate assembly according to claim 1, characterized in that, The first fixing part includes a first end remote from the plate; the method for manufacturing the cover plate assembly further includes: The first end is pressed toward the second surface to form a first anti-torsion structure on the inner surface of the first fixing part.

11. The method for preparing the cover plate assembly according to claim 6, characterized in that, The splitting step includes: An anti-torsion groove is formed on the stepped portion.

12. The method for preparing the cover plate assembly according to claim 1, characterized in that, The punching step includes: The edge of the through hole is punched at least twice from the second surface toward the first surface, so that the diameter of the through hole increases gradually and forms a cylindrical protrusion protruding from the first surface.

13. The method for preparing the cover plate assembly according to claim 1, characterized in that, The first fixing part includes a first end remote from the plate; the method for manufacturing the cover plate assembly further includes: The first end is pressed toward the second surface so that the first end bends toward the center line of the first fixing part.

14. A method for preparing a cover plate assembly according to any one of claims 1 to 13, characterized in that, The first fixing part and the second fixing part define an accommodating space; the method for manufacturing the cover plate assembly further includes: The pole with the sealing part is fixed in the receiving space.

15. A cover plate assembly, characterized in that, The cover plate assembly is prepared by the method of preparation of the cover plate assembly according to any one of claims 1 to 14, the cover plate assembly comprising: a cover plate, the cover plate comprising a cover plate body made of at least a portion of a plate and a first fixing portion, and a receiving space formed by a through hole; The first fixing part includes a first sub-part extending along the first direction. The first sub-part includes a first root and a second root disposed along a second direction. The first root is closer to the receiving space than the second root. The first root is integrally formed and connected to the cover plate body. The second root is discontinuously disposed with the cover plate body and abuts against the first surface. The second direction is perpendicular to the first direction.

16. The cover plate assembly according to claim 15, characterized in that, On one side of the centerline of the accommodating space, the minimum dimension of the end of the first sub-part away from the cover plate body along the second direction is L4, and the sum of the dimensions of the first root and the second root along the second direction is L3, where L3 > L4.

17. The cover plate assembly according to claim 15, characterized in that, The outer wall of the first sub-part is inclined relative to the center line of the receiving space in the first direction.

18. The cover plate assembly according to claim 17, characterized in that, The first sub-part satisfies at least one of the following conditions: The inner wall of the first sub-part is parallel to the first direction; The inclination angle of the outer wall of the first sub-part is b, where 0° < b ≤ 10°.

19. The cover plate assembly according to claim 16, characterized in that, On one side of the centerline of the accommodating space, the straight-line distance between the inner and outer edges of the first root along the second direction is L5, and the ratio of L5 to L3 is greater than 0.

65.

20. The cover plate assembly according to claim 15, characterized in that, The cover plate further includes a second fixing part, the second fixing part including a second inner wall; the second inner wall satisfies at least one of the following conditions: The second inner wall is perpendicular to the first direction; Along the first direction, the straight-line distance between the second inner wall and the first surface is H1, where 1mm ≤ H1 ≤ 1.3mm.

21. The cover plate assembly according to claim 15, characterized in that, The thickness of the cover plate body is H3; the cover plate body satisfies at least one of the following conditions: The first fixing part includes a second sub-part, which is integrally formed and connected to the first sub-part and extends along the second direction toward the center line of the receiving space. The dimension of the second sub-part along the first direction is H2, and the ratio of H2 to H3 is 0.14 to 0.

48. The cover plate further includes a second fixing part, the second fixing part having a dimension of H4 along the first direction, and the ratio of H4 to H3 being 0.15 to 0.

5.

22. The cover plate assembly according to claim 15, characterized in that, The cover plate further includes a second fixing part. The first fixing part includes a first inner wall, and the second fixing part includes a second inner wall. The first inner wall, the second inner wall, and the step portion connecting the first inner wall and the second inner wall form the receiving space. The step portion protrudes from the second inner wall in the direction of the first surface.

23. The cover plate assembly according to claim 22, characterized in that, The second surface is provided with a groove surrounding the second fixing part, and the groove extends to the second fixing part along the second direction.

24. The cover plate assembly according to claim 23, characterized in that, The stepped portion is connected to the first inner wall and forms an inner connecting portion; along the first direction, the projection of the inner connecting portion on the second surface is located within the groove.

25. The cover plate assembly according to any one of claims 22 to 24, characterized in that, It includes an electrode post and an insulating sealing structure, wherein the electrode post and the insulating sealing structure are at least partially placed within the receiving space, and the cover plate and the electrode post are connected through the insulating sealing structure; the insulating sealing structure includes an upper insulating part and a sealing part.

26. The cover plate assembly according to claim 25, characterized in that, At least one of the first fixing part, the pole post, and the step part is provided with an anti-torsion structure; The anti-torsion structure provided in the first fixing part is a first anti-torsion structure, and the upper insulating part is formed with a first insulating anti-torsion structure; one of the first anti-torsion structure and the first insulating anti-torsion structure is a recessed groove structure, and the other is a protrusion structure fitted into the groove structure. The anti-torsion structure provided on the pole post is a second anti-torsion structure, and the upper insulating part is formed with a second insulating anti-torsion structure; one of the second anti-torsion structure and the second insulating anti-torsion structure is a groove structure, and the other is a protrusion structure fitted into the groove structure; The step portion is provided with an anti-torsion structure, which is an anti-torsion groove, and the upper insulating portion is provided with a third insulating anti-torsion structure; the third insulating anti-torsion structure is fitted into the anti-torsion groove.

27. A battery cell, characterized in that, It includes a housing, an electrode assembly, and a cover plate assembly as described in any one of claims 15 to 26, the cover plate assembly being connected to the housing, and the electrode assembly being disposed within the space formed by the cover plate assembly and the housing.

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