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

Abstract

The invention provides a preparation method of a cover plate assembly, the cover plate assembly and a battery monomer, and the preparation method of the cover plate assembly comprises the following steps: a preparation step: providing a plate which comprises a first surface and a second surface; the plate is stamped from the first face to the second face to form a boss protruding out of the second face, the boss comprises a boss end face far away from the first face in the thickness direction of the plate, and a through hole is formed in the boss; hole flanging, wherein the edge of the through hole is punched from the end face of the boss to the first face, so that an annular protrusion protruding out of the first face in the thickness direction of the plate is formed; the annular protrusion comprises a protrusion end face away from the first face in the thickness direction of the plate. And a material splitting step: stamping the part, close to the inner wall, of the annular bulge from the bulge end face to the second face so as to form a first fixing part which protrudes out of the second face and is close to the boss end face. According to the preparation method of the cover plate assembly, the cover plate assembly and the battery cell provided by the invention, the safety of the battery cell can be improved.

Description

Technical Field

[0001] 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

[0002] In the development of battery technology, besides improving the performance of individual battery cells, safety is also a crucial issue that cannot be ignored. If the safety of individual battery cells cannot be guaranteed, then those cells cannot be used. Therefore, how to enhance the safety of individual battery cells is a pressing technical problem that needs to be solved in battery technology. Summary of the Invention

[0003] In view of this, the purpose of this application is to provide a method for preparing a cover plate assembly, a 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.

[0004] To achieve the above objectives, the first aspect of this application provides a method for manufacturing a cover plate assembly, comprising: Preparation steps: Provide a sheet material, the sheet material including a first surface and a second surface disposed opposite to each other along the thickness direction of the sheet material; Stamping step: The sheet metal is stamped from the first surface to the second surface to form a boss protruding from the second surface. The boss includes a boss end face away from the first surface along the thickness direction of the sheet metal. A through hole is formed on the boss, and the through hole passes through the boss along the thickness direction of the sheet metal. Flipping step: The edge of the through hole is punched from the end face of the boss towards the first surface to form an annular protrusion protruding from the first surface along the thickness direction of the plate; the annular protrusion includes a protruding end face away from the first surface along the thickness direction of the plate. Splitting step: The portion of the annular protrusion near the inner wall is punched from the protruding end towards the second surface to form a first fixing part that protrudes from the second surface and is close to the end face of the boss.

[0005] Optionally, after the stamping step, a groove is formed on the first surface that is recessed toward the second surface, and the position of the groove corresponds to the position of the boss; The flanging step includes: Before the edge of the through hole is punched from the direction of the boss end facing the first surface, the bottom surface of the groove is supported from the direction of the first surface facing the second surface to support the boss.

[0006] Optionally, a transition fillet is formed between the inner wall of the annular protrusion and the second surface; After the hole-flipping step and before the splitting step, the following steps are also included: Upsetting step: The protruding end face is pressed from the first face to the second face to reduce the radius of the transition fillet.

[0007] Optionally, the portion of the annular protrusion near the outer wall forms an annular substructure extending along the thickness direction of the plate, and the method for manufacturing the cover plate assembly further includes: Bending step: Press the end of the annular substructure away from the plate in the direction of the axis of the through hole and bend it toward the axis of the through hole so that the annular substructure forms a second fixing part.

[0008] Optionally, the through hole, the second fixing part, and the first fixing part define a mounting hole; after the bending step, the method further includes: The electrode assembly steps include: Clean the mounting holes; The electrode post with the sealing part is inserted into the mounting hole; Material is filled into the mounting hole to form an upper insulating part, and the pole post is fixed to the mounting hole through the upper insulating part.

[0009] Optionally, the flanging step includes: The edge of the through hole is punched at least twice from the second surface in the direction of the first surface, so that the diameter of the through hole increases gradually and the annular protrusion is formed.

[0010] Based on the same inventive concept, a second aspect of this application also provides a cover plate assembly, comprising: a cover plate, the cover plate including a cover plate body, the cover plate body including a first surface and a second surface disposed opposite to each other along the thickness direction, and a mounting hole penetrating the first surface and the second surface; the second surface being provided with a boss in an annular structure surrounding the mounting hole; and a first fixing part, the first fixing part being an annular structure connected to the surface of the boss facing the mounting hole.

[0011] Optionally, it also includes a second fixing part; the first surface is provided with an annular groove that is recessed toward the second surface, and the position of the annular groove corresponds to the position of the boss; the second fixing part is an inverted L-shaped structure connected to the corner of the annular groove.

[0012] Optionally, the second fixing part, the first fixing part, and the cover plate body are integrally formed. The cover plate assembly further includes a pole post and an upper insulating part. The pole post passes through the mounting hole, and the upper insulating part connects the pole post and the second fixing part. The upper insulating part is at least partially located in the annular groove and at least partially located in the mounting hole. Along the thickness direction of the cover plate, the maximum depth of the annular groove is h, and the thickness of the cover plate body is H1, with the ratio of h to H1 being 0.1 to 1; where the units of h and H1 are both mm; or, Along the radial direction of the annular groove, the minimum straight-line distance from the outer edge of the annular groove to the inner wall of the second fixing part is L, and the thickness of the cover plate body is H1, 1 / 3×H1≤L; where the units of H1 and L are both mm.

[0013] Based on the same inventive concept, a third aspect of this application also provides a battery cell, including a housing and a cover assembly as described in the second aspect, the cover assembly being connected to the housing; A first fillet is formed between the boss and the second surface, the radius of which is R1, R1 ≥ 0.2 mm; and / or, The first surface is provided with an annular groove that is recessed toward the second surface. Along the radial direction of the annular groove, a second rounded corner is formed between the groove wall away from the axis and the groove bottom. The radius of the second rounded corner is R2, and R2≥0.2mm.

[0014] As can be seen from the above, the method for manufacturing the cover plate assembly, the cover plate assembly, and the battery cell provided in this application form a boss protruding from the second surface through a stamping step, providing a structural basis for forming the first fixing part protruding from the second surface. Before the first fixing part is formed, due to the presence of the stamping step, a boss protruding from the second surface will be formed in a part of the sheet material. In other words, in the thickness direction of the sheet material, the boss is obtained by stamping the sheet material from the first surface to the second surface. When forming the second fixing part in the subsequent splitting step, the direction of stamping the protruding end face is the same as the direction of stamping the sheet material to obtain the boss.

[0015] During the splitting process, the material is subjected to significant stretching (especially in the thickness direction) at the location where the first fixing part directly connects to other parts of the sheet metal, making the final cover plate assembly prone to cracking at this point. However, the stamping process moves part of the sheet metal in the splitting direction before the splitting process. Therefore, when the first fixing part is formed, the material moves a smaller distance in the thickness direction at the location where it directly connects to other parts of the sheet metal, resulting in less stretching. Consequently, cracks or even delamination are less likely to occur at the connection between the boss and the sheet metal. Furthermore, forming the first fixing part on the boss allows for a larger distance between the first fixing part and the first surface in the stamping direction of the splitting process, without needing to be far from the boss. This satisfies the positional requirements of the first fixing part along the cover plate thickness direction, providing ample space for installing other structures (such as poles) in the cover plate assembly. It also reduces the height difference between the first fixing part and adjacent structures, thereby reducing the tensile force at the connection point and minimizing the stretching of the material, thus reducing the risk of cracks or delamination at that location. For the cover plate in the application, the connection between the first fixing part and the cover plate body can have high structural strength, and the connection between the first fixing part and the cover plate body is more reliable, which helps to improve the safety of the battery cell. Attached Figure Description

[0016] 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.

[0017] Figure 1 This is a partial cross-sectional schematic diagram of a battery cell with the first structure according to an embodiment of this application; Figure 2 This is a partial cross-sectional schematic diagram of the hole-opening step in the preparation method of the cover plate of the first structure in this application embodiment; Figure 3 This is a partial cross-sectional schematic diagram of the perforation step in the preparation method of the cover plate of the first structure in this application embodiment; Figure 4 This is a partial cross-sectional schematic diagram of the splitting step in the preparation method of the cover plate of the first structure in this application embodiment; Figure 5 This is a schematic flowchart illustrating the preparation method of the cover plate assembly with the second structure according to an embodiment of this application; Figure 6a This is a partial cross-sectional schematic diagram of the preparation step in the method for manufacturing the cover plate assembly of the second structure according to an embodiment of this application; Figure 6b This is a cross-sectional view of the stamping step in the preparation method of the cover plate assembly of the second structure in this application embodiment, showing the first part of the protrusion being formed. Figure 6c This is a cross-sectional view of the part where the through hole is first formed in the stamping step of the preparation method of the cover plate assembly of the second structure in this application embodiment; Figure 6d This is a partial cross-sectional view of the stamping step after forming the boss and through hole in the preparation method of the cover plate assembly of the second structure in this application embodiment; Figure 6e This is a partial cross-sectional view of the method for preparing a cover plate assembly with a second structure according to an embodiment of this application, in the flanging step, where the plate is first punched to form an annular protrusion. Figure 6f This is a partial cross-sectional view of the supporting boss in the flanging step of the method for preparing the cover plate assembly of the second structure according to an embodiment of this application. Figure 6g This is a partial cross-sectional view of the method for preparing a cover plate assembly with a second structure according to an embodiment of this application, in which the sheet metal is stamped a second time to form an annular protrusion during the flanging step. Figure 6h This is a partial cross-sectional schematic diagram of the upsetting step in the preparation method of the cover plate assembly of the second structure in this application embodiment; Figure 6i This is a partial cross-sectional schematic diagram of the splitting step in the preparation method of the cover plate assembly of the second structure in this application embodiment; Figure 6j This is a partial cross-sectional view of the first extrusion of the annular substructure during the bending step in the preparation method of the cover plate assembly of the second structure according to the embodiments of this application. Figure 6k This is a partial cross-sectional view of the last extrusion of the annular substructure in the bending step of the method for preparing the cover plate assembly of the second structure according to the embodiments of this application. Figure 6l This is a partial cross-sectional schematic diagram of the preparation method of the cover plate assembly with the second structure according to the present application, in which the pole post is inserted through the mounting hole; Figure 6m This is a partial cross-sectional schematic diagram of the fixed pole in the preparation method of the cover plate assembly of the second structure in this application embodiment; Figure 7 This is a partial cross-sectional schematic diagram of the cover plate assembly of the second structure according to an embodiment of this application; Figure 8 This is a schematic diagram of a battery cell with a second structure according to an embodiment of this application.

[0018] Explanation of reference numerals in the attached figures: 1000, Cover plate assembly; 100. Cover plate; 110. Cover plate body; 111. First surface; 1111. First region; 1112. Second region; 112. Second surface; 113. Mounting hole; 120. Fixing structure; 121. Second fixing part; 122. First fixing part; 130. Boss; 131. Boss end face; 140. First fillet; 150. Second fillet; 200, pole post; 210, pole post body; 220, protrusion; 300, Sealing part; 400, Upper insulating part; 500, Lower insulating part; 2000, Housing; 3000, Electrode Assembly; 4000, Plate; 4100, Through hole; 4200, Annular protrusion; 4210, Protrusion end face; 4220, Annular substructure; 4230, Transition fillet; 4300, Groove; 4310, Annular groove; 5000, raised stamping die; 6000, support die; 7000, Bending die; 7100, Conical surface; 8000, Hole-expanding mold; 9000, Annular limiting mold; 10000, Annular pressing mold. Detailed Implementation

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] Figure 1 A partial cross-sectional schematic diagram of the battery cell of the first structure is shown.

[0025] like Figure 1 In some embodiments, the battery cell includes a cover assembly 1000 and an electrode assembly 3000. The cover assembly 1000 includes a cover 100, a terminal post 200, an upper insulating portion 400, a lower insulating portion 500, and a sealing portion 300. For example, the terminal post 200 may include a positive terminal post and a negative terminal post. The positive terminal post is electrically connected to the positive tab of the electrode assembly 3000 (the positive tab is formed by the current collector of the positive electrode sheet of the electrode assembly 3000 extending outward) to form the positive electrode of the battery cell. The negative terminal post is electrically connected to the negative tab of the electrode assembly 3000 (the negative tab is formed by the current collector of the negative electrode sheet of the electrode assembly 3000 extending outward) to form the negative electrode of the battery cell.

[0026] Specifically, the cover plate 100 includes a cover plate body 110 and a fixing structure 120 connected to the cover plate body 110. The cover plate body 110 is provided with a thickness direction (e.g., ...) Figure 1 A mounting hole 113 (hereinafter referred to as the first direction) is formed through the cover plate 110. A fixing structure 120 is arranged around the mounting hole 113. The fixing structure 120 includes a second fixing part 121 and a first fixing part 122. The second fixing part 121 is at least partially located on the side of the cover plate body 110 away from the electrode assembly 3000 along the first direction. The first fixing part 122 is at least partially located on the side of the cover plate body 110 closer to the electrode assembly 3000 along the first direction. The electrode post 200 is fitted with a sealing part 300 and passes through the mounting hole 113. The electrode post 200 can cooperate with the first fixing part 122 to compress the sealing part 300, so that the sealing part 300 produces a sealing effect. The second fixing part 121 and the electrode post 200 are fixedly connected by the upper insulating part 400, so that the electrode post 200 is fixed to the cover plate 100 and the sealing part 300 maintains the sealing effect.

[0027] For example, in combination Figure 1 One end of the second fixing part 121 is directly connected to the cover plate body 110. The portion of the second fixing part 121 near this end extends in the first direction away from the electrode assembly 3000. The portion of the second fixing part 121 away from this end can be horizontally aligned with the axis of the mounting hole 113 (e.g., Figure 1 The line can extend in the direction of the dotted line (in the diagram), or it can extend upwards at an angle towards the axis of the mounting hole 113.

[0028] For example, the portion of the first fixing part 122 that is directly connected to the cover plate body 110 may extend toward the electrode assembly 3000, while the other portions extend toward the axis of the mounting hole 113.

[0029] For example, the pole post 200 may include a columnar pole post body 210 and a protrusion 220 that protrudes radially from the pole post body 210. Along a first direction, the protrusion 220 is located between the second fixing portion 121 and the first fixing portion 122, and the sealing portion 300 is disposed between the protrusion 220 and the first fixing portion 122. The first fixing portion 122 supports the sealing portion 300 and the second protrusion 220, and the protrusion 220 and the first fixing portion 122 cooperate to compress the sealing portion 300.

[0030] As can be seen from the foregoing, the first fixing part 122 and the second fixing part 121 play a crucial role in the reliable connection between the terminal post 200 and the cover plate 100. If the structural strength of the connection between the first fixing part 122 and the cover plate body 110 (hereinafter referred to as the second connection) is low, or if the structural strength of the connection between the second fixing part 121 and the cover plate body 110 (hereinafter referred to as the first connection) is low, not only may cracks or even breakage occur at the first and second connections during use, but also during the manufacturing of the cover plate 100, the second fixing part 121 or the first fixing part 122 and the cover plate body 110 are prone to breakage, seriously affecting the yield of the cover plate 100. When the battery cell uses a cover plate 100 with cracks, the low reliability of the connection between the terminal post 200 and the cover plate 100 will also have an adverse impact on the safety of the battery cell.

[0031] To address the aforementioned issues, in some embodiments, a method for preparing the cover plate 100 of the first structure is provided. By machining the plate 4000, the same plate 4000 is integrally formed into a cover plate body 110 and a fixing structure 120, thereby improving the structural strength at the first connection and the structural strength at the second connection.

[0032] Figure 2A partial cross-sectional schematic diagram of the opening step in the fabrication method of the cover plate 100 of the first structure is shown. Figure 3 A partial cross-sectional schematic diagram of the perforation step in the preparation method of the cover plate 100 of the first structure is shown. Figure 4 A partial cross-sectional schematic diagram of the splitting step in the preparation method of the cover plate 100 of the first structure is shown.

[0033] like Figure 2 The hole-making step is as follows: A through hole 4100 is formed on the provided plate 4000. The through hole 4100 penetrates the first surface 111 and the second surface 112 of the plate 4000 along the thickness direction of the plate 4000.

[0034] like Figure 2 and Figure 3 The hole-making process involves pressing the edge of the through hole 4100 from the second surface 112 toward the first surface 111 to form an annular protrusion 4200 that protrudes upward from the plate 4000.

[0035] like Figure 3 and Figure 4 Splitting step: Press down on the top surface of the annular protrusion 4200 near the inner wall of the annular protrusion 4200 so that the pressed part of the annular protrusion 4200 forms a first fixing part 122 that protrudes downward from the plate 4000.

[0036] However, the applicant's research found that during the splitting step, the portion of the annular protrusion 4200 near the inner wall is pressed by a die, causing a portion of the annular protrusion 4200 to move downwards to form the first fixing part 122. Compared to the entire annular protrusion 4200, the portion pressed by the die is less material, resulting in a thinner connection between the first fixing part 122 and the sheet material 4000. Furthermore, when the die presses the first fixing part 122 to protrude from the sheet material 4000, the connection is subjected to significant tensile force, which could potentially cause cracks or even breakage at the connection.

[0037] To address the aforementioned issues, this embodiment provides a method for preparing the cover plate assembly 1000.

[0038] Figure 5 A flowchart illustrating the fabrication method of the cover plate assembly 1000 with the second structure is shown. Figure 6a A partial cross-sectional schematic diagram of the preparation steps in the fabrication method of the cover plate assembly 1000 of the second structure is shown; Figure 6b A partial cross-sectional view of the stamping step in the fabrication method of the cover plate assembly 1000 of the second structure is shown. Figure 6c A partial cross-sectional view of the process of forming the through hole 4100 in the stamping step is shown in the manufacturing method of the cover plate assembly 1000 of the second structure. Figure 6d A partial cross-sectional schematic diagram showing the formation of the boss 130 and the through hole 4100 in the stamping step of the manufacturing method of the cover plate assembly 1000 of the second structure is shown. Figure 6e A partial cross-sectional view showing the fabrication method of the cover plate assembly 1000 of the second structure in the flanging step, where the sheet metal 4000 is first punched to form an annular protrusion 4200; Figure 6f A partial cross-sectional view of the supporting boss 130 during the flanging step is shown in the fabrication method of the cover plate assembly 1000 with the second structure. Figure 6g A partial cross-sectional view showing the fabrication method of the cover plate assembly 1000 of the second structure in the flanging step to form an annular protrusion 4200 by second stamping of the sheet metal 4000. Figure 6h A partial cross-sectional schematic diagram of the upsetting step in the fabrication method of the cover plate assembly 1000 with the second structure is shown; Figure 6i A partial cross-sectional schematic diagram of the splitting step in the fabrication method of the cover plate assembly 1000 with the second structure is shown; Figure 6j The diagram shows a partial cross-sectional view of the first extrusion of the annular substructure 4220 during the bending step in the fabrication method of the cover plate assembly 1000 of the second structure. Figure 6k The diagram shows a partial cross-sectional view of the final extrusion of the annular substructure 4220 during the bending step in the fabrication method of the cover plate assembly 1000 of the second structure. Figure 6l A partial cross-sectional schematic diagram showing the fabrication method of the cover plate assembly 1000 of the second structure, in which the pole post 200 is inserted through the mounting hole 113; Figure 6m A partial cross-sectional schematic diagram of the fixed pole 200 is shown in the fabrication method of the cover plate assembly 1000 of the second structure.

[0039] like Figure 5 The method for preparing the cover plate assembly 1000 provided in this embodiment includes: like Figure 6a S100, Preparation steps: Provide a sheet 4000, which includes a first surface 111 and a second surface 112 disposed opposite to each other along the thickness direction (i.e., the first direction).

[0040] It should be noted that, according to the design structure of the cover plate, a first region 1111 and a second region 1112 located inside the first region 1111 can be pre-divided on the first surface 111.

[0041] For example, the orthographic projection of the first region 1111 along the first direction can be a circle or a polygon, and the orthographic projection of the second region 1112 along the first direction can be a circle or a polygon. The shapes of the two regions can be the same or different.

[0042] It should be noted that the axis of the first region 1111 and the axis of the second region 1112 can coincide. The edge of the orthographic projection of the first region 1111 along the first direction and the edge of the orthographic projection of the second region 1112 along the first direction do not coincide.

[0043] like Figure 6b and Figure 6d S200, stamping step: stamping sheet 4000 from the first surface 111 toward the second surface 112 to form a boss 130 protruding from the second surface 112. The boss 130 includes a boss end face 131 that is away from the first surface 111 along the first direction. A through hole 4100 is formed on the boss 130 and the through hole 4100 passes through the boss 130 along the first direction.

[0044] For example, the first region 1111 of the first surface 111 can be formed by stamping the first area 1111 through a stamping process to form the boss 130.

[0045] It should be noted that the boss end face 131 is substantially perpendicular to the straight line extending along the first direction, or in other words, the boss end face 131 is substantially parallel to the second face 112. The thickness of the sheet 4000 is uniform, and the thickness of the boss 130 is substantially the same as the thickness of the other areas of the sheet 4000 except for the first region 1111. The positions where the boss 130 connects to other parts of the sheet 4000 (e.g., Figure 6b At position a) the material is stretched, and the thickness at this location may be less than the thickness of other areas of the sheet 4000. However, at other locations of the boss 130, due to the smaller degree of stretching, the overall thickness can remain essentially the same as other areas of the sheet 4000. It should be noted that due to the processing precision of the sheet 4000 and the manufacturing process of the cover plate 110, the thickness relationship of different parts of the cover plate 110 should not limit the scope of protection of this invention. The term "same thickness" throughout this document does not mean exact sameness, but rather includes unavoidable deviations during component processing.

[0046] In this embodiment, the thickness of the first region 1111 of the sheet 4000 is the same as the thickness of the other regions besides the first region 1111. When the first region 1111 is stamped to form the boss 130, the edge of the stamped portion (e.g. Figure 6b Although position a in the diagram is also subjected to tensile force, the material thickness allows for a greater degree of elongation, so position a is not prone to cracks or even splits.

[0047] It should be noted that during the fabrication of the cover plate assembly 1000, the boss 130 can be formed first, followed by the through hole 4100, as shown below. Figure 6b and Figure 6d Alternatively, a through hole 4100 can be formed first, followed by the boss 130, as shown below. Figure 6c and Figure 6dIt can also simultaneously form a through hole 4100 and a boss 130.

[0048] When drilling, punching or milling is used to form a through hole 4100 in the second region 1112, reliable support can be provided for other regions of the sheet metal 4000 except for the second region 1112. This prevents external workpieces from applying external force to the material in the second region 1112 when the through hole 4100 is formed. Other regions of the sheet metal 4000, especially those close to the second region 1112, will also be affected by external force and deform due to the lack of reliable support, thus reducing the forming quality of the cover plate assembly 1000.

[0049] like Figure 6d and Figure 6g S300, Flipping step: The edge of the through hole 4100 is punched from the boss end face 131 toward the first face 111 to form an annular protrusion 4200 protruding from the first face 111 along the first direction; the annular protrusion 4200 includes a protruding end face 4210 away from the first face 111 along the first direction.

[0050] During the process of punching the edge of the through hole 4100 from the boss end face 131 toward the first surface 111, the middle part of the boss 130 will be pressed and bulge toward the first surface 111 to gradually form an annular protrusion 4200 protruding from the first surface 111. At the same time, the diameter of the through hole 4100 also increases accordingly. The part of the boss 130 near the edge is not pressed and can maintain its original extension direction, that is, extend along the first direction and protrude from the second surface 112.

[0051] It should be noted that the annular protrusion 4200 is the structural basis for forming the second fixing part 121 and the first fixing part 122.

[0052] like Figure 6g and Figure 6i S400, Splitting step: The portion of the annular protrusion 4200 near the inner wall is punched from the protruding end face 4210 toward the second face 112 to form a first fixing part 122 that protrudes from the second face 112 and is close to the boss end face 131.

[0053] It should be noted that both the inner and outer walls of the annular protrusion 4200 surround the axis of the annular protrusion 4200 and extend radially along the through hole 4100. Figure 6g In the X direction, the outer wall of the annular protrusion at 4200 surrounds the inner wall.

[0054] It should be noted that the first fixing part 122 is arranged around the axis of the through hole 4100.

[0055] For example, in order to prevent the outer diameter of the annular protrusion 4200 from deforming, the outer wall of the annular protrusion 4200 can also be pressed by an annular mold during the extrusion process.

[0056] The annular protrusion 4200 is stamped using a protrusion stamping die 5000. The protrusion stamping die 5000 can be a columnar structure, the projection of which along the first direction covers the inner hole enclosed by the annular protrusion 4200 and partially coincides with the end face 4210 of the protrusion.

[0057] First, align the protruding stamping die 5000 and the annular protrusion 4200 so that the axis of the protruding stamping die 5000 coincides with the axis of the annular protrusion 4200. Then, bring the bottom end of the protruding stamping die 5000 into contact with the protruding end face 4210, and apply pressure to the portion of the protruding end face 4210 near the inner wall of the annular protrusion 4200 to push the portion of the annular protrusion 4200 near the inner wall downwards and change its shape until it protrudes beyond the second surface 112 and approaches the boss end face 131, forming a first fixing part 122 that is at least partially an annular flat plate structure. Due to the presence of the boss 130, the first fixing part 122 is ultimately formed along the first direction at a position close to the boss end face 131, without protruding excessively beyond the boss end face 131. Therefore, the connection position between the first fixing part 122 and the boss 130 (e.g., Figure 6i The tensile force at position b is relatively small, making it less prone to cracking or even splitting. (Reference) Figure 4 and Figure 6i The distance between the first fixing part 122 and the second surface 112 in the first direction is greater than the distance between the first fixing part 122 and the boss end face 131 in the first direction. Figure 4 The risk of cracks or even splitting is greater at the location where the first fixing part 122 connects to the second surface 112.

[0058] The portion of the annular protrusion 4200 near the outer wall 4220 is not compressed and remains in its original position. After further processing, it can form a second fixing part 121 protruding from the first surface 111.

[0059] The method for manufacturing the cover plate assembly 1000 provided in this embodiment forms a boss 130 and a through hole 4100 protruding from the second surface 112 through a stamping step, providing a structural basis for forming the first fixing part 122 protruding from the second surface 112. Since the thickness of the boss 130 is greater than the thickness of the first fixing part 122, cracks or even splits are less likely to occur at the connection between the boss 130 and the plate 4000. At the same time, the first fixing part 122 is formed on the basis of the boss 130, so that the first fixing part 122 can protrude from the second surface 112 as long as it is close to the end face 131 of the boss along the first direction. This satisfies the positional requirements of the first fixing part 122 along the first direction and reduces the height difference between the first fixing part 122 and the adjacent structure (i.e., the boss 130), thereby reducing the tensile force on the connection position between the first fixing part 122 and the adjacent structure, and reducing the risk of cracks or even splits at that position. For the cover plate 100 formed by the manufacturing method of the cover plate assembly 1000 of this embodiment, the connection between the first fixing part 122 and the cover plate body 110 can have high structural strength, and the connection between the first fixing part 122 and the cover plate body 110 has strong reliability. In some embodiments, the second fixing part 121, the first fixing part 122 and the cover plate body 110 are integrally formed.

[0060] like Figure 6f In some embodiments, after the stamping step, the first surface 111 is formed with a groove 4300 that is recessed toward the second surface 112, and the position of the groove 4300 corresponds to the position of the boss 130. The steps for drilling holes include: Before the edge of the through hole 4100 is punched from the end face 131 of the boss toward the first face 111, the bottom surface of the support groove 4300 is supported from the first face 111 toward the second face 112 to support the boss 130.

[0061] Understandably, during the hole-making process, the edge of the through hole 4100 is punched from the boss end face 131 towards the first surface 111. This may cause the boss end face 131 to be recessed into the first surface 111 under the punching action. As mentioned above, the area near the edge of the boss end face 131 needs to protrude beyond the second surface 112 to provide a structural basis for forming the first fixing part 122. If the area near the edge of the boss end face 131 is recessed into the first surface 111, then in order to ensure that the height of the first fixing part 122 protruding beyond the second surface 112 meets the design requirements, the first fixing part 122 needs to protrude significantly beyond the boss end face 131. However, there is still a significant risk of cracks or even splitting at the connection between the first fixing part 122 and the boss 130.

[0062] To avoid the above problems, the boss 130 needs to be supported during the hole-making process to prevent the boss end face 131 from being recessed.

[0063] Specifically, after the stamping step, the first region 1111 of the first surface 111 is compressed to form a groove 4300 recessed in the first surface 111. Since the annular protrusion 4200 is located in the first region 1111, the outer wall of the annular protrusion 4200 will be spaced from the groove wall of the groove 4300 (i.e., the edge of the first region 1111) to form an annular groove 4310.

[0064] When preparing for the hole-flipping step, although the annular protrusion 4200 has not yet been formed, the approximate position of the annular groove 4310 is also known because the final size of the annular protrusion 4200 is known. Before punching the edge of the through hole 4100, the support mold 6000 can be inserted into the groove 4300 and placed at the position of the annular groove 4310. The shape of the support mold 6000 can match the bottom shape of the annular groove 4310 and abut against the bottom of the groove 4300.

[0065] Understandably, the shape of the support mold 6000 matches the bottom shape of the annular groove 4310, meaning the contour shape of the contact surface between the support mold 6000 and the groove bottom is the same as or similar to the contour shape of the bottom of the annular groove 4310. For example, when the bottom contour is annular, the contour of the contact surface of the support mold 6000 can also be annular, and the entire support mold 6000 can be a columnar structure formed by extending the annular area of ​​the contact surface. Furthermore, the dimensions of the support mold 6000 can be the same as the bottom dimension of the annular groove 4310 to provide better support, or the dimensions of the support mold 6000 can be slightly smaller than the bottom dimension of the annular groove 4310 to prevent interference between the support mold 6000 and the annular groove 4310 due to machining errors.

[0066] Since the bottom of the groove 4300 is set opposite to the end face 131 of the boss, in the first direction, the support mold 6000 supports and limits the bottom of the groove 4300, which is to support and limit the end face 131 of the boss, and can effectively prevent the end face 131 of the boss from being recessed.

[0067] Meanwhile, during the formation of the annular protrusion 4200, the supporting mold 6000 can also limit the outer wall of the annular protrusion 4200, thus making the internal shape of the final annular groove 4310 more regular and meeting the design requirements.

[0068] It should be noted that the depth of different areas of the final annular groove 4310 can be the same or different. For example, having a basically uniform depth of the annular groove 4310 can give the bottom surface of the annular groove 4310 a high degree of flatness and a high forming quality, which is beneficial to improving the reliability when installed with other structures. Alternatively, a concave-convex structure can be formed on the bottom surface of the annular groove 4310 to make the aforementioned depths different. The concave-convex structure can be used to install with other structures to achieve anti-torsion effect for some structures, thereby improving the reliability and safety of the cover plate assembly 1000 and the battery cells.

[0069] like Figure 6g and Figure 6h In some embodiments, a transition fillet 4230 is formed between the inner wall of the annular protrusion 4200 and the second surface 112; After the hole-making step and before the splitting step, the process also includes: Upsetting step: The protruding end face 4210 is punched from the first face 111 toward the second face 112 to reduce the radius of the transition fillet 4230.

[0070] Understandably, after the annular protrusion 4200 is formed, the second surface 112 naturally bends with the inner wall of the annular protrusion 4200 to form a transition fillet 4230. However, the applicant has found that when the radius of the transition fillet 4230 is large, there is less material at the transition fillet 4230 compared to the rest of the annular protrusion 4200. When the first fixing part 122 is subsequently formed, there may be a material shortage when the first fixing part 122 is formed at the transition fillet 4230, resulting in low structural strength and poor safety of the first fixing part 122 at this location.

[0071] To avoid the aforementioned problems, this embodiment uses an annular pressing die 10000 to press the protruding end face 4210, so that the material fills the transition fillet 4230, and the radius of the transition fillet 4230 is correspondingly reduced. Specifically, the annular pressing die 10000 applies an external force toward the second surface 112 to the protruding end face 4210 in a first direction, causing the material of the annular protrusion 4200 to move along the corresponding direction under force (e.g., Figure 6f (In the downward direction), at this time, the material of part of the annular protrusion 4200 moves and fills the position of part of the transition fillet 4230, so that the radius of the transition fillet 4230 is reduced or eliminated. This helps to improve the structural strength of the first fixing part 122 on the one hand, and also helps to improve the connection strength between the first fixing part 122 and the boss 130 on the other hand, preventing breakage at the connection between the two.

[0072] Meanwhile, in order to avoid uncontrollable deformation of the inner wall of the second surface 112 and the annular protrusion 4200 during the stamping of the protrusion end face 4210, a mold that supports the second surface 112 and the boss end face 131 and fits against the inner wall of the annular protrusion 4200 can be set during the stamping process. The surface of the mold that fits against the inner wall of the annular protrusion 4200 and the surface that supports the boss end face 131 transition at a right angle. On the one hand, this prevents the inner diameter of the annular protrusion 4200 from changing, and on the other hand, it can shape the material filling the transition fillet 4230 to reduce the radius of the transition fillet 4230.

[0073] like Figure 6i , Figure 6j and Figure 6k In some embodiments, the portion of the annular protrusion 4200 near its outer wall forms an annular substructure 4220 extending along a first direction. The method for manufacturing the cover assembly 1000 further includes: S500, Bending Step: Press the end of the annular substructure 4220 away from the plate 4000 (hereinafter referred to as the end of the annular substructure 4220) toward the axis of the through hole 4100, and bend it toward the axis of the through hole 4100 so that the annular substructure 4220 forms the second fixing part 121.

[0074] It should be noted that the second fixing part 121 is arranged around the axis of the through hole 4100.

[0075] Before the bending step, the portion of the annular protrusion 4200 near the outer wall is not compressed during the splitting step, forming an annular substructure 4220 that still extends along the first direction.

[0076] like Figure 6j For the annular substructure 4220, the end of the annular substructure 4220 is first squeezed at least once by the bending die 7000. The bending die 7000 has a conical surface 7100, and the end of the annular substructure 4220 is brought together and inclined towards the axis of the through hole 4100 under the squeezing action of the conical surface 7100.

[0077] It should be noted that when the end of the annular substructure 4220 is repeatedly extruded using the bending die 7000, the angle between the conical surface 7100 and the vertical surface can be gradually increased, thereby gradually decreasing the angle between the end of the annular substructure 4220 and the horizontal surface. Furthermore, the conical surface 7100 can include a partially rounded transition structure, creating a rounded transition between the end of the annular substructure 4220 and the non-end portion of the annular substructure 4220 when the annular substructure is brought together and tilted, thus improving the molding quality.

[0078] After at least one extrusion of the conical surface 7100, such as Figure 6kFinally, the portion near the end of the annular substructure 4220 can be pressed by a flat mold to bend the portion near the end of the annular substructure 4220 toward the axis of the through hole 4100. At the same time, the corresponding portion can also move toward the first surface 111 to form the second fixing part 121 of the annular substructure 4220.

[0079] In addition to the aforementioned extrusion of the end of the annular substructure 4220 by bending die 7000, the end of the annular substructure 4220 can also be stamped by a punch to replace the extrusion of the end of the annular substructure 4220 by the conical surface 7100 of bending die 7000. Under the stamping action of the punch, the end of the annular substructure 4220 converges and tilts towards the axis of the through hole 4100. The tilt angle of the punch can be adjusted according to the tilt angle of the end of the annular substructure 4220, ultimately forming the second fixing part 121 of the annular substructure 4220.

[0080] like Figure 6k , Figure 6l and Figure 6m In some embodiments, the through hole 4100, the second fixing part 121, and the first fixing part 122 define the mounting hole 113; after the bending step, the method further includes: S600 and pole piece 200 assembly steps include: S610, Cleaning mounting hole 113.

[0081] After the mounting hole 113 is formed, it is necessary to clean the inside of the mounting hole 113 to avoid the presence of metal foreign objects such as metal shavings or metal burrs in the mounting hole 113. This is to prevent the metal foreign objects from reducing the electrical clearance and creepage distance between the hole wall of the mounting hole 113 and the pole post 200, and to prevent the metal foreign objects from scratching the sealing part 300 and adversely affecting the sealing performance of the sealing part 300.

[0082] like Figure 6l S620, the pole post 200 with the sealing part 300 is inserted into the mounting hole 113.

[0083] After the second fixing part 121 and the first fixing part 122 are formed, the second fixing part 121, the first fixing part 122, and the through hole 4100 located between them define the mounting hole 113 for mounting the pole post 200. The pole post 200, fitted with the sealing part 300, can be inserted into the mounting hole 113. The first fixing part 122 will limit the structure of the pole post 200 (e.g., the protrusion 220 of the pole post 200) to prevent the pole post 200 from passing through the inner hole formed by the first fixing part 122 and coming out of the mounting hole 113. The sealing part 300 can at least seal the part between the pole post 200 and the first fixing part 122, such as... Figure 6l The radial direction of the mounting hole 113 is... Figure 6l The portion between the electrode post 220 and the first fixing part 122 in the X direction, and the portion between the protrusion 220 of the electrode post 200 in the first direction and the first fixing part 122. This prevents external moisture from entering the battery cell or electrolyte from leaking out of the battery cell, thus reducing the battery cell's lifespan.

[0084] It should be noted that before or after the cover plate 100 is prepared, the sealing part 300 can be connected to the protrusion 220 of the pole post 200 by means of adhesive bonding, hot pressing, or fitting, so as to reduce the installation difficulty of the sealing part 300. When connecting the sealing part 300 to the pole post 200, it is necessary to ensure that after the pole post 200 is inserted into the mounting hole 113, the sealing part 300 can contact the first fixing part 122, and the protrusion 220 and the first fixing part 122 are located on opposite sides of the sealing part 300 along the first direction. In this way, the protrusion 220 and the first fixing part 122 can cooperate to squeeze the sealing part 300, so that the sealing part 300 is deformed and a sealing effect is produced.

[0085] The pole post 200 connected to the sealing part 300 can directly pass through the inner hole formed by the second fixing part 121 and be installed into the mounting hole 113.

[0086] like Figure 6m S630, fill the mounting hole 113 with material to form the upper insulating part 400 by injection molding, and fix the pole post 200 to the mounting hole 113 through the upper insulating part 400.

[0087] In other words, in some embodiments, the upper insulating portion 400 is integrally formed.

[0088] by Figure 6m The structure and orientation shown are illustrated below. The pole post 200 is pressed downwards, while the cover plate 100 remains in its current position. As the pole post 200 moves downwards under pressure, the protrusion 220 presses downwards against the sealing portion 300, while the first fixing portion 122 supports the sealing portion 300 upwards. Under the combined action of the protrusion 220 and the first fixing portion 122, the sealing portion 300 is deformed under pressure, thereby forming a seal between at least the protrusion 220 and the first fixing portion 122.

[0089] Subsequently, while the sealing part 300 remains under pressure and deformation, the upper insulating part 400 is formed through injection molding. After the upper insulating part 400 connects to the second fixing part 121 and the pole body 210, the relative position between the pole 200 and the cover plate 100 is fixed, ensuring a reliable connection between the pole 200 and the cover plate 100. Simultaneously, the upper insulating part 400 within the mounting hole 113 connects with the sealing part 300 and fills the remaining space within the mounting hole 113, ensuring good insulation and sealing between the pole 200 and the cover plate 100.

[0090] like Figure 6e and Figure 6g In some embodiments, the flanging step includes: The edge of the through hole 4100 is punched at least twice from the end face 131 of the boss toward the first face 111, so that the diameter of the through hole 4100 increases gradually and an annular protrusion 4200 is formed.

[0091] Specifically, such as Figure 6e First, a reaming die 8000 with an outer diameter slightly larger than the current through hole 4100 is used. The edge of the through hole 4100 is punched by the boss end face 131. After the reaming die 8000 is inserted into the through hole 4100, the hole wall of the through hole 4100 is squeezed, so that the pressure-bearing part of the plate 4000 bulges towards the first surface 111. At the same time, the diameter of the through hole 4100 also increases under the action of the reaming die 8000.

[0092] When the expanding die 8000 extrudes the sheet 4000, an annular limiting die 9000 can be set on the first surface 111 around the through hole 4100. The annular limiting die 9000 can limit the outer edge of the part that protrudes towards the first surface 111 to prevent the part from bending outward.

[0093] like Figure 6g A larger-diameter expanding die 8000 is used, and the edge of the through hole 4100, which has been expanded once, is pressed by the boss end face 131, so that the pressure part of the plate 4000 continues to bulge towards the first surface 111. At the same time, the outer diameter of the bulging part and the diameter of the through hole 4100 also become larger.

[0094] The above operation can be repeated multiple times using a reaming mold 8000 with a gradually increasing outer diameter until the raised portion forms an annular protrusion 4200 whose outer and inner diameters both meet the preset dimensions. This annular protrusion 4200 extends from the plate 4000 in a direction away from the first surface 111 along a first direction.

[0095] 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.

[0096] Figure 7 A partial cross-sectional schematic diagram of the cover plate assembly 1000 of the second structure is shown.

[0097] like Figure 7The cover plate assembly 1000 provided in this embodiment includes: a cover plate 100, the cover plate 100 including a cover plate body 110, the cover plate body 110 including a first surface 111 and a second surface 112 disposed opposite to each other along the thickness direction, and a mounting hole 113 passing through the first surface 111 and the second surface 112; the second surface 112 is provided with a boss 130 having an annular structure surrounding the mounting hole 113; and a first fixing part 122, the first fixing part 122 being an annular structure connected to the surface of the boss 130 facing the mounting hole 113.

[0098] For example, the cover assembly 1000 may also include a lower insulating portion 500 connected to the side of the cover body 110 away from the first surface 111.

[0099] In this embodiment, the beneficial effects of providing the boss 130 and connecting the first fixing part 122 to the surface of the boss 130 facing the mounting hole 113 have been described above and will not be repeated here.

[0100] like Figure 7 In some embodiments, the cover plate 100 further includes a second fixing part 121. The first surface 111 is provided with an annular groove 4310 that is recessed toward the second surface 112. The position of the annular groove 4310 corresponds to the position of the boss 130. The second fixing part 121 is an inverted L-shaped structure connected to the corner of the annular groove 4310.

[0101] It should be noted that the second fixing part 121 is also a ring structure. For example... Figure 7 In the longitudinal section of the annular structure, one side of the annular groove 4310 has an inverted L-shaped structure, that is, the portion extending along the first direction and the portion extending radially along the annular groove 4310 are constructed into an inverted L-shaped structure. The portion extending along the first direction is connected to the corner of the annular groove 4310, while the portion extending radially along the annular groove 4310 is away from the cover plate body 110.

[0102] like Figure 7 The second fixing part 121, the first fixing part 122 and the cover plate body 110 are integrally formed. The cover plate assembly 1000 also includes a pole post 200 and an upper insulating part 400. The pole post 200 passes through the mounting hole 113. The upper insulating part 400 connects the pole post 200 and the second fixing part 121. The upper insulating part 400 is at least partially located in the annular groove 4310 and at least partially located in the mounting hole 113. Along the thickness direction of the cover plate 100, the maximum depth of the annular groove 4310 is h, and the thickness of the cover plate body 110 is H1. The ratio of h to H1 is 0.1 to 1. The units of h and H1 are both mm.

[0103] Understandably, the bottom of the annular groove 4310 formed by stamping may have an uneven surface, which makes the depth of the annular groove 4310 different in different areas. When the upper insulating part 400 is fitted into the annular groove 4310, and the annular groove 4310 has different depths, it is understandable that the upper insulating part 400 and the groove bottom of the annular groove 4310 with different depths can achieve staggered engagement, thereby preventing the upper insulating part 400 from rotating around the axis of the mounting hole 113 and achieving an anti-torsion effect.

[0104] As can be seen from the foregoing, the annular groove 4310 can be used to fill the support mold 6000 to provide limiting support for the boss end face 131.

[0105] The upper insulating part 400 is fitted into the annular groove 4310, which can improve the connection reliability between the upper insulating part 400 and the cover plate body 110. Since the pole 200 is fixed to the cover plate 100 through the upper insulating part 400, when the connection reliability between the upper insulating part 400 and the cover plate 100 is high, the connection reliability between the pole 200 and the cover plate 100 will also be improved accordingly. This helps to ensure that the pole 200 and the cover plate 100 are relatively fixed, which can ensure that the pole 200 can form a reliable connection with the external circuit. It also helps to improve the sealing performance of the upper insulating part 400 and the sealing part 300.

[0106] For example, the ratio of h to H1 can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1.

[0107] If h is too large, the straight-line distance between the bottom of the annular groove 4310 and the second surface 112 along the first direction will be too small, meaning the material thickness between them will be too small, potentially causing cracks or even breakage at that location. If h is too small, the height of the boss 130 protruding from the second surface 112 will also be too small. In order for the height of the first fixing part 122 protruding from the second surface 112 to meet the design requirements, the first fixing part 122 needs to protrude a larger height from the end face 131 of the boss. However, there is still a significant risk of cracks or even breakage at the connection between the first fixing part 122 and the boss 130.

[0108] Therefore, in order to avoid the above problems, this embodiment designs the ratio of h to H1 to be 0.1 to 1, which can not only avoid cracks or even breakage at the position corresponding to the annular groove 4310, but also effectively reduce the risk of cracks or even breakage at the connection between the first fixing part 122 and the boss 130.

[0109] like Figure 7 In some embodiments, along the radial direction of the annular groove 4310 as... Figure 7In the X direction, the minimum straight-line distance from the outer edge of the annular groove 4310 to the inner wall of the second fixing part 121 is L, and the thickness of the cover plate body 110 is H1, 1 / 3×H1≤L; where the units of H1 and L are both mm.

[0110] Therefore, the minimum straight-line distance from the outer edge of the annular groove 4310 to the inner wall of the second fixing part 121 can be obtained by the following method: along a certain radial direction of the annular groove 4310, the thickness of the second fixing part 121 in that direction can be obtained, and the unit of the thickness is mm; along the same radial direction, the width of the annular groove 4310 can be obtained, and the unit of the width is mm. Adding the two together will give the straight-line distance from the outer edge of the annular groove 4310 to the inner wall of the second fixing part 121 in the corresponding radial direction; repeating this process will give a number of the aforementioned straight-line distances, and the minimum value of the straight-line distance is L, and the unit of L is also mm.

[0111] For example, L can be 1 / 3×H1, 2 / 5×H1, 1 / 2×H1, 2 / 3×H1, or 3 / 4×H1. In some embodiments, H1 can be 3mm, and L can be 1.5mm. In these embodiments, the width of the annular groove 4310 in the radial direction of the aforementioned minimum straight-line distance L can be L1, where L1 ≥ 0.8mm; for example, L1 can be 0.8mm, 0.85mm, 0.9mm, 0.95mm, or 1mm. Alternatively, in these embodiments, the thickness of the second fixing part 121 in the radial direction of the annular groove 4310 corresponding to the aforementioned minimum straight-line distance L can be L2, where L2 ≥ 0.7mm; for example, L2 can be 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 0.95mm, or 1mm.

[0112] For example, in some embodiments, H1 can also be 1mm, 1.8mm, 2.1mm, 2.5mm or 2.7mm, etc.

[0113] If L is too small, one possibility is that the thickness of the second fixing part 121 will be too small, resulting in lower structural strength of the second fixing part 121 itself. This could lead to cracks or even breakage at the connection between the second fixing part 121 and the cover plate body 110. Another possibility is that the width of the annular groove 4310 will be too small, meaning that when the annular protrusion 4200 is formed in the above-mentioned hole-flipping step, the inner diameter of the annular protrusion 4200 will be too large. Consequently, the diameter of the mounting hole 113 formed in the subsequent steps will also be too large. When installing the pole post 200 into the mounting hole 113, the pole post 200 may have difficulty making smooth contact with the first fixing part 122 in the first direction. It may easily tip over and get stuck in the inner hole formed by the first fixing part 122, or directly pass through the inner hole formed by the first fixing part 122 and detach from the mounting hole 113, resulting in low assembly efficiency of the cover plate assembly 1000.

[0114] To avoid the above problems, in this embodiment, L is designed to be 1 / 3×H1≤L. On the one hand, this ensures that the second fixing part 121 has high structural strength, so that the second fixing part 121 can be reliably connected to the cover plate body 110. The second fixing part 121 can also effectively fix the pole post 200 through the upper insulating part 400, so that the pole post 200 and the cover plate 100 can be reliably connected. On the other hand, the inner diameter of the hole formed by the first fixing part 122 can be smaller than the outer diameter of the protrusion 220 of the pole post 200, so as to ensure that the first fixing part 122 can support the fixing part 220 relatively stably and reliably, so as to reliably limit the pole post 200, which helps to improve the assembly efficiency of the cover plate assembly 1000.

[0115] 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.

[0116] like Figure 7 and Figure 8 The battery cell includes a housing 2000 and a cover assembly 1000 as described in the above embodiments. The cover assembly 1000 is connected to the housing 2000. A first fillet 140 is formed between the boss 130 and the second surface 112. The radius of the first fillet 140 is R1, and R1 ≥ 0.2 mm.

[0117] It should be noted that the connection between the cover plate assembly 1000 and the housing 2000 can form a space for accommodating the electrode assembly 3000, and the second surface 112 of the cover plate 100 in the cover plate assembly 1000 faces the electrode assembly 3000.

[0118] For example, R1 can be 0.2mm, 0.3mm, 0.4mm or 0.5mm.

[0119] Reference Figure 7 In some embodiments, the boss 130 in the battery cell is formed by stamping a portion of the cover plate 100 from top to bottom. Therefore, the material at the connection between the boss 130 and the cover plate body 110 tends to move downward. Especially at the connection between the boss 130 and the second surface 112, the material is stretched and flows downward and the thickness is reduced. If the first fillet 140 is not provided or R1 is too small, the shape here is roughly a right angle or obtuse angle turn. At the sharp corner, the material has poor fluidity due to the abrupt change in the structural shape. Compared with other positions of the boss 130 and the cover plate body 110, cracks are more likely to occur, which is not conducive to improving the structural strength and safety of the cover plate assembly 1000 and the battery cell.

[0120] The first fillet 140 prevents right-angle structures from appearing at the connection between the boss 130 and the second surface 112, thereby reducing stress concentration at the connection and improving the connection reliability between the boss 130 and the cover plate body 110. In this embodiment, R1 is designed to be R1≥0.2mm, which allows for more uniform material flow at the first fillet 140 during the formation of the boss 130, improving molding quality and reducing stress concentration.

[0121] like Figure 7 In some embodiments, along the radial direction of the annular groove 4310, a second fillet 150 is formed between the groove wall away from the axis and the groove bottom of the annular groove 4310, and the radius of the second fillet 150 is R2, where R2≥0.2mm.

[0122] For example, R2 can be 0.2mm, 0.3mm, 0.4mm or 0.5mm.

[0123] If a second fillet 150 is not provided between the groove wall and the bottom of the annular groove 4310 away from the axis, a right-angle structure will appear at the connection between the bottom and the groove wall of the corresponding annular groove 4310. Consequently, stress concentration is likely to occur, resulting in lower structural strength at the edge of the annular groove 4310 in the cover plate 100. Furthermore, in some embodiments, the battery cell includes an upper insulating portion 400 that extends to the connection between the boss 130 and the second surface 112. If a right-angle structure is formed at this location, the material flow will be poor during injection molding of the upper insulating portion 400, easily leading to shrinkage cavities or uneven material filling.

[0124] To avoid the aforementioned problems, this embodiment provides a second fillet 150 between the groove wall and the bottom of the annular groove 4310 away from the axis, and designs R2 to be R2≥0.2mm. This prevents right-angle structures from appearing at the connection between the bottom and the wall of the corresponding annular groove 4310, thereby reducing stress concentration at the connection between the bottom and the wall and helping to improve the structural strength of the edge of the annular groove 4310 in the cover plate 100. At the same time, it can improve the material flow at this location when the upper insulating part 400 is injection molded, preventing shrinkage cavities or uneven material filling, which is beneficial to improving the connection strength between the upper insulating part 400 and other structures, and improving the insulation performance of the cover plate assembly 1000 and the battery cell.

[0125] It should be noted that some embodiments of this application have been described above. Other embodiments are within the scope of the appended claims.

[0126] 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.

[0127] 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.

[0128] 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 is limited to these examples; under the concept 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 detail for the sake of brevity.

[0129] 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.

[0130] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this application. 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: Preparation steps: Provide a sheet material, the sheet material including a first surface and a second surface disposed opposite to each other along the thickness direction of the sheet material; Stamping step: The sheet metal is stamped from the first surface to the second surface to form a boss protruding from the second surface. The boss includes a boss end face away from the first surface along the thickness direction of the sheet metal. A through hole is formed on the boss, and the through hole passes through the boss along the thickness direction of the sheet metal. Flipping step: The edge of the through hole is punched from the end face of the boss towards the first surface to form an annular protrusion protruding from the first surface along the thickness direction of the plate; the annular protrusion includes a protruding end face away from the first surface along the thickness direction of the plate. Splitting step: The portion of the annular protrusion near the inner wall is punched from the protruding end towards the second surface to form a first fixing part that protrudes from the second surface and is close to the end face of the boss.

2. The method for preparing the cover plate assembly according to claim 1, characterized in that, After the stamping step, a groove is formed on the first surface that is recessed toward the second surface, and the position of the groove corresponds to the position of the boss. The flanging step includes: Before the edge of the through hole is punched from the direction of the boss end facing the first surface, the bottom surface of the groove is supported from the direction of the first surface facing the second surface to support the boss.

3. The method for preparing the cover plate assembly according to claim 1, characterized in that, A transition fillet is formed between the inner wall of the annular protrusion and the second surface; After the hole-flipping step and before the splitting step, the following steps are also included: Upsetting step: The protruding end face is pressed from the first face to the second face to reduce the radius of the transition fillet.

4. The method for preparing the cover plate assembly according to claim 1, characterized in that, The portion of the annular protrusion near its outer wall forms an annular substructure extending along the thickness direction of the plate. The method for manufacturing the cover plate assembly further includes: Bending step: Press the end of the annular substructure away from the plate in the direction of the axis of the through hole and bend it toward the axis of the through hole so that the annular substructure forms a second fixing part.

5. The method for preparing the cover plate assembly according to claim 4, characterized in that, The through hole, the second fixing part, and the first fixing part define a mounting hole; Following the bending step, the following is also included: The electrode assembly steps include: Clean the mounting holes; The electrode post with the sealing part is inserted into the mounting hole; Material is filled into the mounting hole to form an upper insulating part, and the pole post is fixed to the mounting hole through the upper insulating part.

6. The method for preparing the cover plate assembly according to claim 1, characterized in that, The flanging step includes: The edge of the through hole is punched at least twice from the second surface in the direction of the first surface, so that the diameter of the through hole increases gradually and the annular protrusion is formed.

7. A cover plate assembly, characterized in that, include: A cover plate, the cover plate including a cover plate body, the cover plate body including a first surface and a second surface disposed opposite to each other along the thickness direction, and a mounting hole penetrating the first surface and the second surface; the second surface is provided with a boss in an annular structure surrounding the mounting hole; The first fixing part is an annular structure connected to the surface of the boss facing the mounting hole.

8. The cover plate assembly according to claim 7, characterized in that, It also includes a second fixing part; The first surface is provided with an annular groove that is recessed toward the second surface, and the position of the annular groove corresponds to the position of the boss; the second fixing part is an inverted L-shaped structure connected to the corner of the annular groove.

9. The cover plate assembly according to claim 8, characterized in that, The second fixing part, the first fixing part, and the cover plate body are integrally formed. The cover plate assembly further includes a pole post and an upper insulating part. The pole post passes through the mounting hole. The upper insulating part connects the pole post and the second fixing part. The upper insulating part is at least partially located in the annular groove and at least partially located in the mounting hole. Along the thickness direction of the cover plate, the maximum depth of the annular groove is h, and the thickness of the cover plate body is H1, with the ratio of h to H1 being 0.1 to 1; where the units of h and H1 are both mm; or, Along the radial direction of the annular groove, the minimum straight-line distance from the outer edge of the annular groove to the inner wall of the second fixing part is L, and the thickness of the cover plate body is H1, 1 / 3×H1≤L; where the units of H1 and L are both mm.

10. A single battery cell, characterized in that, It includes a housing and a cover assembly as described in any one of claims 7 to 9, the cover assembly being connected to the housing; A first fillet is formed between the boss and the second surface, the radius of which is R1, R1 ≥ 0.2 mm; and / or, The first surface is provided with an annular groove that is recessed toward the second surface. Along the radial direction of the annular groove, a second rounded corner is formed between the groove wall away from the axis and the groove bottom. The radius of the second rounded corner is R2, and R2≥0.2mm.

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