Secondary battery top cover and secondary battery

Abstract

The utility model discloses a secondary battery top cover. Comprising a cover plate, an isolation piece, a conductive block, a pole and a sealing piece, wherein a pole hole is formed in the cover plate in a penetrating manner; the isolation piece is arranged on the surface of the cover plate and is provided with a pole via hole corresponding to the pole hole; the conductive block is arranged in the isolation piece; a riveting groove which does not upwards penetrate through the conductive block is upwards formed in the conductive block from the bottom surface, a riveting part which is riveted and fixed with the riveting groove is arranged at the top of the pole, and the riveting groove comprises a riveting flange which is formed by extending from the periphery of the riveting groove along the radial inner side and at least covers part of the riveting groove; the riveting part comprises a riveting convex edge which extends into the riveting groove and is at least partially located on the upper side of the riveting flange. The utility model also comprises a secondary battery.

Description

Technical Field

[0001] This application relates to the field of secondary batteries, and particularly to a secondary battery top cover and a secondary battery. Background Art

[0002] Battery technology is widely used in electric vehicles, creating great economic benefits for society and being conducive to environmental protection and emission reduction. The most important performances of vehicle batteries include safety, energy density, shock resistance, etc. Power batteries include several battery cells, and each battery cell is connected together in series and parallel to form a powerful vehicle battery pack. Each battery cell includes a battery housing, a battery core encapsulated in the battery housing, an electrolyte, and a battery top cover for closing the battery housing. The forms of battery cells are diverse, and the most commonly used ones on the market include cylindrical batteries, square batteries, blade batteries, etc. Although the battery shapes are diverse, the product component composition principles are the same, all including components such as a housing and a top cover.

[0003] Chinese Patent Application No. 202320643615.0 discloses a cover plate assembly, including: a top cover sheet having a first end face and a second end face facing away from each other; an installation hole provided in the top cover sheet, the installation hole penetrating from the first end face to the second end face; a pole column assembly including a pole column, a pole column riveting block, and a first insulating member, the pole column being installed in the installation hole, and the pole column riveting block being used to rivet the pole column into the installation hole on the first end face; the first insulating member being clamped between the pole column riveting block and the first end face to insulate the pole column riveting block from the first end face; a sealing member wrapping around the pole column to electrically isolate the pole column from the top cover sheet at the installation hole. In the above technology, a riveting hole needs to be formed through the pole column riveting block. After the pole column passes upward through the installation hole and the riveting hole, the top of the pole column is extruded outward and riveted on the edge of the pole column riveting block to achieve fixation. First, in the foregoing structure, the connection between the pole column and the pole column riveting block is directly exposed to the air, which will accelerate product aging and affect product life; second, since electrical connection needs to be achieved by welding both outside and inside the pole column, but the existence of the riveting hole reduces the effective welding area between the external BusBar and the internal soft connection or pole ear, resulting in the need to increase the volume or area of the pole column to ensure the welding area to allow high-voltage current to pass through, thereby increasing the weight of the cover plate assembly; third, the electrical connection between the pole column and the pole column riveting block is only achieved through the connection between the side surface of the pole column and the inner wall surface of the riveting hole, and the conductive contact surface is insufficient. Summary of the Utility Model

[0004] In view of this, it is necessary to provide a secondary battery top cover and a secondary battery with relatively stable service life.

[0005] To solve the above technical problems, the present application provides a top cover for a secondary battery, which includes a cover plate formed with a pole hole therethrough, a separator disposed on the surface of the cover plate and provided with a pole through hole corresponding to the pole hole, a conductive block disposed within the separator, a pole passing through the pole through hole and the pole hole and riveted and fixed to the conductive block, and a seal member sleeved outside the pole to achieve sealing. The conductive block is provided with a riveting groove that does not penetrate upward from the bottom surface. The top of the pole is provided with a riveting portion riveted and fixed to the riveting groove. The riveting groove includes a riveting flange extending radially inward along the periphery of the riveting groove and covering at least a part of the riveting groove. The riveting portion includes a riveting convex edge extending into the riveting groove and at least partially located above the riveting flange.

[0006] Preferably, the riveting groove further includes a middle protrusion protruding downward from the middle of the top of the riveting groove and a riveting ring groove formed around the middle protrusion. The riveting flange at least partially covers the riveting ring groove. The middle of the top of the riveting portion is provided with a middle groove corresponding to the middle protrusion. The riveting convex edge extends from the periphery of the middle groove.

[0007] Preferably, a card slot is formed between the peripheral surface of the riveting portion of the pole and the riveting convex edge. The riveting flange is located within the card slot and is supported and pressed by the pole.

[0008] Preferably, the outer peripheral surface of the middle protrusion is inclined to form a riveting guiding slope. Before riveting the pole and the conductive block, the riveting convex edge of the riveting portion extends vertically upward. After riveting, the riveting convex edge is bent and snapped into the riveting ring groove.

[0009] Preferably, before riveting, the inner diameter of the riveting convex edge is smaller than the maximum outer diameter of the riveting guiding slope and larger than the minimum outer diameter of the riveting guiding slope.

[0010] Preferably, the bottom surface of the conductive block is squeezed and recessed upward around the riveting ring groove to form a limiting recess. The squeezed metal extends radially inward to form the riveting flange. The upper surface of the cover plate is recessed downward around the pole hole to form a groove for accommodating the separator. The pole hole is formed through the groove area. The separator includes a bottom wall, an outer side wall extending upward from the periphery of the bottom wall, and a conductive block accommodating groove surrounded by the bottom wall and the outer side wall. The pole through hole is formed through the middle of the bottom wall. The bottom wall protrudes upward around the pole through hole to form a limiting flange that is snapped into the limiting recess at the bottom of the conductive block. The bottom wall protrudes downward around the pole through hole to form a separating ring that is inserted into the pole hole of the cover plate.

[0011] Preferably, the top cover of the secondary battery further includes a lower plastic part attached to the bottom surface of the cover plate. The lower plastic part includes a through hole with an inner diameter larger than that of the pole hole and corresponding to the pole hole. The pole includes a connecting part abutting against the bottom surface of the lower plastic part, a pressing step extending upward from the connecting part and having an outer diameter smaller than that of the connecting part, a wrapped part extending upward from the pressing step and having an outer diameter smaller than that of the pressing step, a penetrating part extending upward from the wrapped part and having an outer diameter smaller than that of the wrapped part, and the riveting part is formed by extending upward from the top of the penetrating part.

[0012] Preferably, the outer periphery of the penetrating part is wrapped by the inner wall surface of the pole through hole of the separator and is electrically isolated from the pole hole of the cover plate. The bottom surface of the isolation ring of the separator supports on the upper surface of the wrapped part.

[0013] Preferably, the sealing part is wrapped around the outer periphery of the wrapped part of the pole. The sealing part includes an isolation side wall isolating the wrapped part from the inner wall surface of the pole hole and a pressing wall integrally extending downward from the isolation side wall and having a radial width larger than that of the isolation side wall. The pressing wall is clamped between the bottom surface of the cover plate and the upper surface of the connecting part of the pole to achieve sealing.

[0014] To solve the above technical problems, the present application also provides a secondary battery, including the aforementioned top cover of the secondary battery, a battery cell housing with one end open, a battery cell encapsulated in the battery cell housing, and a current collector electrically connecting the battery cell and the top cover of the secondary battery. The top cover of the secondary battery closes the open end of the battery cell housing, and the battery cell is charged and discharged through the top cover of the secondary battery.

[0015] Compared with the prior art, the conductive block of the present application is arranged from the bottom surface without penetrating the riveting groove on the surface upward. The top of the pole is provided with a riveting part riveted and matched with the riveting groove. Specifically, the riveting of the riveting part is achieved by arranging a riveting flange extending to below the riveting groove at the bottom of the riveting groove, so that the riveting position is not exposed to the outside to obtain a longer service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings:

[0017] Figure 1 is a three-dimensional combined view of the top cover of the secondary battery of the present application;

[0018] Figure 2 is a three-dimensional exploded view of the top cover of the secondary battery of the present application;

[0019] Figure 3This is an exploded perspective view of another angle of the top cover of the secondary battery of the present application;

[0020] Figure 4 is a cross-sectional view along the Figure 1 dashed line A-A shown in the figure;

[0021] Figure 5 is a cross-sectional view along the Figure 2 dashed line B-B shown in the figure;

[0022] Figure 6 This is a cross-sectional view of the conductive block and the pole post before riveting of the top cover of the secondary battery of the present application.

[0023] Description of the reference numerals

[0024] Cover plate - 10; Cover plate body - 11; Groove - 12; Pole post hole - 13; Pole post assembly - 20; Conductive block - 21; Top surface - 211; Riveting surface - 212; Riveting groove - 213; Riveting ring groove - 214; Intermediate protrusion - 215; Inclined surface - 2141, 2481; Riveting guiding inclined surface - 2151; Riveting flange - 216; Arc surface - 2161; Limiting depression - 217; Spacer - 22; Outer side wall - 221; Conductive block receiving groove - 222; Pole post through hole - 223; Bottom wall - 225; Limiting flange - 226; Isolation ring - 224; Sealing member - 23; Perforation - 231; Isolation side wall - 232; Extrusion wall - 233; Extrusion area - 234; Pole post - 24; Connection part - 241; Extrusion step - 242; Wrapped part - 243; Penetrating part - 244; Riveting part - 245; Intermediate groove - 246; Card slot - 247; Riveting convex edge - 248; Lower plastic part - 30; Main body part - 31; Through hole - 33; Air hole - 32; Limiting groove - 34. Detailed implementation manners

[0025] To make the objectives, technical solutions, and advantages of the present application clearer, the technical solutions of the present application will be clearly and completely described below in conjunction with specific embodiments of the present application and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments.

[0026] In the present application, Figure 1 the X direction shown in the figure is the transverse direction, the Y direction is the longitudinal direction, and the Z direction is the upper side in the vertical direction.

[0027] Please refer to Figures 1 to 3 as shown in the figure, the top cover of the secondary battery of the present application includes a cover plate 10 provided with at least one pole post hole 13, a lower plastic part 30 attached to the lower surface of the cover plate 10, and a pole post assembly 20 assembled in the pole post hole and having upper and lower ends exposed on both upper and lower sides of the cover plate 10. An explosion-proof valve 40 or a liquid injection hole (not shown) is further provided on the cover plate 10.

[0028] The cover plate 10 includes a cover plate body 11 and a groove 12 formed by recessing downward from the upper surface of the cover plate body 11. The pole hole 13 penetrates through the cover plate body 11 from within the groove 12, and there is at least one pole hole 13.

[0029] The lower plastic part 30 includes a main body part 31 attached to the lower surface of the cover plate body 11, a plurality of air holes 32 provided at the position corresponding to the explosion-proof valve 40, a through hole 33 opened at the position corresponding to the pole hole 13, and a limiting groove 34 formed by recessing upward on the bottom surface of the main body part 31 around the outer periphery of the through hole 33.

[0030] Please continue to refer to Figure 4 、 Figure 5 As shown, the pole assembly 20 includes an isolation part 22 installed on the upper side of the cover plate 10, a conductive block 21 positioned within the isolation part 22 and electrically isolated from the cover plate 10, a pole 24 that passes upward through the pole hole 13 and is riveted and fixed to the conductive block 21, and a seal 23 sleeved outside the pole 24 to isolate the pole 24 from the inner wall surface of the pole hole 13. The pole 24 is electrically isolated from the lower surface of the cover plate body 11 through the lower plastic part 30.

[0031] The conductive block 21 includes a top surface 211 exposed to the outside and a bottom surface 212 opposite to the top surface 211. The surface of the top surface 211 is flat without a hole or groove structure. A riveting groove 213 is formed by machining upward on the bottom surface 212, and the riveting groove 213 does not penetrate upward through the top surface 211 of the conductive block 21. The riveting groove 213 is formed by a stamping and stretching process. Specifically, the riveting groove 213 includes a riveting ring groove 214 formed by upward extrusion, a middle protrusion 215 protruding downward from the middle of the top of the riveting groove 213, and a riveting flange 216 formed by extruding the periphery of the riveting groove 213 of the conductive block 21 and extending toward the riveting groove 213, and a limiting depression 217 is formed at the extrusion position. The riveting ring groove 214 surrounds the outer periphery of the middle protrusion 215. The riveting flange 216 at least partially extends below the riveting ring groove 214 and covers a part of the edge of the riveting ring groove 214. Preferably, it is better that the riveting flange 216 covers one-third of the width of the riveting ring groove 214. The periphery of the middle protrusion 215 is a bevel structure to form a riveting guiding bevel 2151. The edge of the riveting ring groove 214 also forms a bevel 2141, and the upper side edge of the riveting flange 216 forms an arc surface 2161.

[0032] The manufacturing of the conductive block 21 can include various methods. The preferred method is to use a stamping process. The stamping process includes the following steps:

[0033] S01. Provide a conductive block made of metal material. In this step, metal plates can be provided to stamp a number of conductive blocks or a single conductive block at one time. However, only one conductive block can be formed by stamping a single conductive block at one time, resulting in low efficiency.

[0034] S02. Stamp the bottom surface of the conductive block or the metal plate to make it concave to form the middle protrusion 215 and the riveting ring groove 214 structure. In this step, only conventional extrusion processing is required to complete the processing.

[0035] S03. Extrude the bottom surface of the periphery of the riveting ring groove 214 to make the metal flow to the lower part of the riveting ring groove 214 to form the riveting flange 216 and the limiting depression 217.

[0036] In this step, to ensure the regular extension of the riveting flange 216, a die core can be placed in the riveting ring groove 214 first during extrusion and then pushed out after extrusion. Specifically, to enable the die core to exit smoothly, the method of shrinking the core rod can be adopted. Alternatively, when forming the riveting flange 214 by extrusion, first make the metal flow downward to form a vertically state riveting flange 214, and then bend the vertically state riveting flange 214 towards the center. The bent state does not need to be bent to the horizontal state, and a certain inclination angle is sufficient. The bending flatness can be completed by the action with the pole 24 during the riveting operation.

[0037] S04. If the conductive block 21 is formed by stamping a metal plate, it is necessary to divide a number of integrated conductive blocks 21 into independent conductive blocks 21 through this step.

[0038] In addition to being manufactured by the above stamping method, the conductive block 21 can also be obtained by methods such as CNC machining. However, the cost of CNC machining is relatively high and it is not an optimal option.

[0039] The lower surface of the middle protrusion 215 is flat and does not exceed the upper surface of the riveting flange 216.

[0040] The spacer 22 is obtained by injection molding of an insulating material. The spacer 22 includes a bottom wall 225, an outer side wall 221 protruding upward from the periphery of the bottom wall 225, a conductive block receiving groove 222 formed by enclosing the bottom wall 225 and the outer side wall 221, a pole post through hole 223 penetrating the bottom wall 225, a limiting flange 226 protruding upward from the periphery of the pole post through hole 223 and snapping into the fiber groove 217 of the conductive block 21, and an isolation ring 224 extending downward from the periphery of the pole post through hole 223. The conductive block 21 has a square structure, and the conductive block receiving groove 222 is square to receive the conductive block 21 and electrically isolate the conductive block 21 from the cover plate 10. The bottom wall 225 is embedded in the groove 12 on the cover plate body 11 for positioning, the isolation ring 224 is inserted into the pole post hole 13, and the pole post hole 13 of the cover plate 10 corresponds to the pole post through hole 223 of the spacer 22.

[0041] The seal 23 includes a perforation 231 for sleeving outside the pole post 24, an isolation side wall 232 formed on the outside of the perforation 231, and a pressing side wall 233 located outside the perforation 231 and at the lower part of the isolation side wall 232. The radial width of the pressing side wall 233 is greater than the radial width of the isolation side wall 232. Thus, a pressing area 234 is formed on the upper surface of the pressing side wall 233.

[0042] The pole post 24 includes a connecting portion 241, a pressing step 242 extending upward from the connecting portion 241, a wrapped portion 243 extending upward from the pressing step 242, a penetrating portion 244 extending upward from the wrapped portion 243, and a riveting portion 245 extending upward from the penetrating portion 244. The connecting portion 241 is snapped into the limiting groove 34 on the bottom side of the lower plastic part 30, and the bottom surface of the connecting portion 241 is exposed below the cover plate 10 for welding and conduction with a current collector (not shown). The outer diameters of the connecting portion 241, the pressing boss 242, the wrapped portion 243, the penetrating portion 244, and the riveting portion 245 decrease in sequence.

[0043] The outer diameter of the connecting portion 241 is greater than the inner diameters of the pole hole 13 and the through hole 33 of the lower plastic part 30. The outer diameter of the extrusion step 242 is greater than the inner diameter of the pole hole 33 and not greater than the inner diameter of the through hole 33. The outer diameter of the wrapped portion 243 is less than the outer diameter of the pole hole 13, and the seal 23 is sleeved on the outer peripheral surface of the wrapped portion 243. The inner wall surface of the perforation 231 of the seal 23 tightly wraps around the outer peripheral surface of the wrapped portion 243. The bottom surface of the extrusion wall 233 of the seal 23 fits on the upper surface of the extrusion step 242, and the outer diameter of the extrusion wall 233 is greater than the inner diameter of the pole hole 13. The outer diameter of the wrapped portion 243 is less than the pole through hole 223 of the spacer 22.

[0044] The riveting portion 245 is riveted into the riveting groove 213 of the conductive block 21. The riveting portion 245 includes a middle groove 246 formed by a downward depression in the middle of the top to correspond to the middle protrusion 215 of the conductive block 21, a riveting flange 248 formed by extending upward from the periphery of the middle groove 246 and then bending radially outward, and a clamping groove 247 formed between the riveting flange 248 and the top surface of the penetrating portion 244. The edge of the riveting flange 248 is squeezed into the riveting ring groove 214 of the conductive block 21 and is limited and clamped by the riveting flange 216, and the riveting flange 216 is located in the clamping groove 217. The middle protrusion 215 and the middle groove 246 are in close fit. The edge of the riveting flange 248 and the inclined surface 2141 outside the riveting ring groove 214 form an inclined surface 2481.

[0045] The isolation ring 224 of the spacer 22 is inserted into the pole hole 13 and is located between the inner wall surface of the pole hole 13 and the outer peripheral surface of the penetrating portion 244 of the pole 24 to electrically isolate the pole 24 from the cover plate 10. The bottom surface of the isolation ring 224 is located on the top surface of the wrapped portion 243 and is limited. The bottom of the isolation ring 224 simultaneously presses down on the top of the isolation side wall 232 of the seal 23, and the extrusion wall 233 of the seal 23 is clamped and extruded by the extrusion step 242 and the bottom surface of the cover plate body 11 to achieve sealing. Here, the inner diameter of the through hole 33 of the lower plastic part 30 is greater than the inner diameter of the pole hole 13.

[0046] Please refer with emphasis to Figure 6 As shown, the conductive block 21 and the pole 24 are collectively referred to as the riveting structure. Before riveting, the top of the riveting flange 248 of the pole 24 is not bent but is in a vertical state so that its outer diameter is less than the inner diameter at the riveting flange 216 of the conductive block 21. At this time, the inner edge of the riveting flange 248 can be set in the shape of an inclined surface 2481, or the top of the riveting flange 248 is a flat structure.

[0047] During riveting, the conductive block 21 and the pole column 24 move relative to each other. The inner edge of the riveting convex edge 248 first contacts the riveting guiding inclined surface 2151 on the outer periphery of the middle protrusion 215, guiding the riveting convex edge 248 to deform and flow radially outward. Then, through riveting pressure, the riveting convex edge 248 is bent outward and extended into the riveting ring groove 214 and engaged and fixed with the riveting flange 216. The bottom of the riveting flange 216 is supported and squeezed by the upper surface of the penetrating portion 244 and is not suspended, so that the riveting convex edge 248 is stably fixed on the upper side of the riveting flange 216. The setting of the middle protrusion 215 is extremely important in the riveting operation of this application. In addition to guiding the riveting convex edge 248 to bend and move radially outward, it also eliminates the possibility of the riveting convex edge 248 flowing towards the center of the circle. At the same time, the middle protrusion 215 finally squeezes into the middle groove 246 of the pole column 24 and maintains electrical contact.

[0048] In another embodiment, to facilitate the processing of the riveting flange 216, the riveting flange 216 is in an inclined state rather than a horizontal state (the reason has been described above). During riveting, the surface of the penetrating portion 244 of the pole column 24 squeezes the riveting flange 216 upward to the horizontal state at the same time. However, this processing method is not the optimal solution. During the process of squeezing and bending the riveting flange 216, it may affect the strength of the riveting flange 216, such as causing internal injuries, etc., resulting in defects. However, with the development of processing technology and materials, this processing method in this embodiment does not rule out taking into account the product yield, processing efficiency and convenience.

[0049] Compared with the prior art, in the riveting structure, the top cover of the secondary battery and the secondary battery of this application, by providing a non-penetrating riveting groove 213 on the conductive block 21, and the pole column 24 is arranged in the riveting portion 245 riveted by the riveting groove 213, the pole column 24 is not exposed to the air, and the riveting positions are not exposed, reducing the oxidation effect of the riveting positions by external air and increasing the service life of the product; at the same time, the internal riveting structure also makes the top surface of the conductive block 21 flat and smooth to increase the effective welding area with the conductive connector (not shown), improving the welding quality and efficiency; in the existing through-conductive-block riveting structure, the electrical conduction between the pole column 24 and the conductive block is mainly through partial outer peripheral surfaces of the pole column 24 and the conductive block 21, and the contact surface is limited. In this application, through the internal riveting structure, the pole column 24 and the conductive block 21 are kept in close contact on the top surface and part of the outer peripheral surface. Through some irregular structure designs, such as the middle protrusion 215, the middle groove 246, the inclined surface and other structures, the contact conduction area is further increased, the current passing ability is improved, and the heat generation is reduced.

[0050] In this embodiment, a pair of riveting grooves 213 and a pair of riveting parts 245 are respectively provided on a conductive block 21 and a pole column 24, so that the bonding force between the conductive block 21 and the pole column 24 can be effectively enhanced, and at the same time, the current passing ability is enhanced. In other embodiments, it may also be sufficient that one riveting groove 213 corresponds to one riveting part 245.

[0051] In one embodiment, the riveting structure 21, 24 may not only be applied to the top cover of the secondary battery, but also to other places where it is needed. In this embodiment, the conductive block 21 and the pole column 24 of the riveting structure may be modified to a first riveting block 21 and a second riveting block 24, and the key is to retain the riveting groove 213 structure of the first riveting block 21 and the riveting part 245 structure of the second riveting block 24.

[0052] The top cover of the secondary battery is applied to the secondary battery. The secondary battery further includes a battery cell housing with one end open, a battery cell encapsulated in the battery cell housing, and a current collector electrically connecting the battery cell and the top cover of the secondary battery. The top cover of the secondary battery closes the open end of the battery cell housing, and the battery cell is charged and discharged through the top cover of the secondary battery.

[0053] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0054] The above embodiments only represent the preferred embodiments of the present invention, and the description is relatively specific and detailed, but it should not be understood as a limitation to the scope of the utility model patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the utility model patent shall be subject to the appended claims.

Claims

1. A secondary battery top cover, comprising a cover plate having a pole hole formed therethrough, an isolating member disposed on the surface of the cover plate and having a pole through hole corresponding to the pole hole, a conductive block disposed in the isolating member, a pole passing through the pole through hole and the pole hole and riveted to the conductive block, and a sealing member sleeved outside the pole to achieve sealing, characterized in that: The conductive block is provided with a rivet groove extending upward from the bottom surface and not penetrating upwardly through the conductive block, and the top of the pole is provided with a rivet portion riveted to the rivet groove, the rivet groove includes a rivet flange extending radially inward from the periphery of the rivet groove and covering at least a portion of the rivet groove, and the rivet portion includes a rivet flange extending into the rivet groove and at least partially located on the upper side of the rivet flange.

2. The secondary battery top cover according to claim 1, characterized in that: The rivet groove also includes a middle protrusion protruding downward from the middle of the top of the rivet groove and a rivet ring groove formed around the middle protrusion. The rivet flange at least partially covers the rivet ring groove. A middle groove corresponding to the middle protrusion is provided in the middle of the top of the rivet portion. The rivet flange is formed by extending from the periphery of the middle groove.

3. The secondary battery top cover according to claim 2, characterized in that: A clamping groove is formed between the peripheral surface of the riveted portion of the pole and the riveted flange, and the riveted flange is located in the clamping groove and is supported and pressed by the pole.

4. The secondary battery top cover according to claim 3, characterized in that: The outer peripheral surface of the middle protrusion is inclined to form a riveting guide slope. Before the pole and the conductive block are riveted, the riveting convex edge of the riveted part extends vertically upward. After riveting, the riveting convex edge is bent and stuck in the riveting ring groove.

5. The secondary battery top cover according to claim 4, characterized in that: Before riveting, the inner diameter of the riveting convex edge is smaller than the maximum outer diameter of the riveting guide inclined surface and larger than the minimum outer diameter of the riveting guide inclined surface.

6. The secondary battery top cover according to claim 4, characterized in that: The bottom surface of the conductive block is upwardly extruded and recessed around the rivet ring groove to form a limiting recess, and the extruded metal extends radially inward to form the riveted flange. The upper surface of the cover plate is located around the pole hole and is recessed downward to form a groove for accommodating the isolation member. The pole hole is formed by passing through the groove area. The isolation member includes a bottom wall, an outer wall extending upward from the periphery of the bottom wall, and a conductive block accommodating groove surrounded by the bottom wall and the outer wall. The pole through hole is formed by passing through the middle of the bottom wall. The bottom wall is located at the periphery of the pole through hole and protrudes upward to form a limiting flange that is stuck in the limiting recess at the bottom of the conductive block. The bottom wall is located at the periphery of the pole through hole and protrudes downward to form an isolation ring inserted into the pole hole of the cover plate.

7. The secondary battery top cover according to claim 6, characterized in that: The secondary battery top cover also includes a lower plastic part attached to the bottom surface of the cover plate, the lower plastic part includes a through hole with an inner diameter greater than the inner diameter of the pole hole and corresponding to the pole hole, the pole includes a connecting portion abutting against the bottom surface of the lower plastic part, an extrusion step extending upward from the connecting portion and with an outer diameter smaller than the outer diameter of the connecting portion, a wrapped portion extending upward from the extrusion step and with an outer diameter smaller than the outer diameter of the extrusion step, and a passing portion extending upward from the wrapped portion and with an outer diameter smaller than the outer diameter of the wrapped portion, and the riveted portion is formed by extending upward from the top of the passing portion.

8. The secondary battery top cover according to claim 7, characterized in that: The outer periphery of the penetration portion is wrapped by the inner wall surface of the pole through hole of the isolating member and is electrically isolated from the pole hole of the cover plate, and the bottom surface of the isolation ring of the isolating member is supported on the upper surface of the wrapped portion.

9. The secondary battery top cover according to claim 8, characterized in that: The seal is wrapped around the outer periphery of the wrapped portion of the pole, and the seal includes an isolation side wall that isolates the wrapped portion from the inner wall of the pole hole and an extrusion wall that extends downward from the isolation side wall and has a radial width greater than the isolation side wall. The extrusion wall is clamped between the bottom surface of the cover plate and the upper surface of the connecting portion of the pole to achieve sealing.

10. A secondary battery, characterized in that: It comprises a secondary battery top cover as claimed in any one of claims 1 to 9, a battery cell shell with one end open, a battery cell encapsulated in the battery cell shell, and a current collector electrically connecting the battery cell and the secondary battery top cover, the secondary battery top cover closes the open end of the battery cell shell, and the battery cell is charged and discharged through the secondary battery top cover.

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