CN216120514U

CN216120514U - Power battery top cover

Info

Publication number: CN216120514U
Application number: CN202121344268.9U
Authority: CN
Inventors: 曾志亮; 杜秋文
Original assignee: Shenzhen Everwin Precision Technology Co Ltd
Current assignee: Shenzhen Changying Precision Technology Co Ltd; Yibin Changying Precision Technology Co ltd
Priority date: 2021-06-16
Filing date: 2021-06-16
Publication date: 2022-03-22
Anticipated expiration: 2031-06-16

Abstract

A power battery top cover comprises a cover plate provided with a pole column hole, a welding ring welded on the periphery of the pole column hole, a sealing ring, a pole column and an insulating body for integrally forming and fixing the pole column in the pole column hole and the welding ring, the pole hole comprises a through hole, a concave part formed at the periphery of the through hole by being concave from the surface of the cover plate and a convex edge formed by being convex upwards from the edge of the concave part, the sealing ring is sleeved on the convex edge, the pole comprises a column body, a contact part formed at the upper part of the column body, a connecting part formed at the lower part of the column body and sleeved in the sealing ring, and an outer convex part which is formed by extending from the middle of the column body along the radial outer side and is propped against the sealing ring, the welding ring comprises a welding bottom surface fixed in the depressed part in a welding mode, an extension wall formed by extending from the inner side of the welding bottom surface obliquely inwards and upwards, and a pressing part formed by bending the top of the extension wall inwards.

Description

Power battery top cover

Technical Field

The application relates to the field of power batteries, in particular to a power battery top cover.

Background

The power battery comprises a plurality of battery monomers, a confluence assembly and a pair of poles, wherein the battery monomers are connected in parallel, and the pair of poles are electrically connected with the confluence assembly and transmit electric energy out. The power battery is characterized in that liquid substances such as electrolyte are injected into the power battery, the sealing performance of the power battery needs to be maintained, the power battery further comprises a shell and a top cover for sealing the shell, and the pole is fixed on the top cover and needs to be electrically isolated by the cover plate of the top cover. Patent application No. 201921132385.1 of the people's republic of China discloses a power battery top cap, which comprises a cover plate and a pole column, wherein the cover plate is provided with a pole column hole, and the pole column is integrally formed in the pole column hole through an insulation body, a sealing ring and a welding ring. The periphery of the pole hole protrudes upwards to form a protruding ring part, the pole is fixed to the lower side of the protruding ring part by the insulating body, the sealing ring is sleeved under the cover plate, the welding ring is sleeved on the outer side below the pole and clamps the sealing ring and then is welded to the welding ring on the lower side of the cover plate, and the pole is fixed inside the welding ring. This technical scheme is difficult location when injection moulding utmost point post, the design of sealing washer has certain defect simultaneously, still needs to examine the sealing performance of insulator nucleation nature.

SUMMERY OF THE UTILITY MODEL

In view of the above, it is desirable to provide a top cover for a power battery, which has good sealing performance and is easy to manufacture.

In order to solve the technical problem, the application provides a power battery top cap, including the apron that is equipped with the utmost point post hole, weld in welding ring, sealing washer, utmost point post of utmost point post hole periphery and incite somebody to action utmost point post integrated into one piece is fixed in insulating body in utmost point post hole and the welding ring, utmost point post hole including perforate, certainly apron surface sunken form in the depressed part of perforation periphery reaches certainly the convex edge that the depressed part edge upwards protrudes and forms, the sealing washer cover is located on the convex edge, utmost point post include the cylinder, form in the contact site on cylinder upper portion, form in the cylinder lower part just embolias connecting portion in the sealing washer and certainly in the middle of the cylinder along radially outwards extending the formation support hold in outer convex part on the sealing washer, welding ring including welded fastening in the depressed part welding bottom surface, from the inboard slant of welding bottom surface in the top extend the extension wall that forms and from the extension wall top inwards bend and form the extension wall top The insulating body comprises a top wall, a clamping part which is connected with the top wall and solidified between the pole and the welding ring, and a covering outer wall which is connected with the top wall and covers the outer side of the welding ring.

Preferably, the top of the convex edge is higher than the surface of the concave part, the sealing ring comprises a compression joint surface located on the upper side of the convex edge, a sleeve hole formed by penetrating through the compression joint surface and used for sleeving the connecting part of the pole, an inner side wall formed by downwards extending from the inner side and the outer side of the compression joint surface, an outer side wall and a buckling groove formed between the inner side wall and the outer side wall and used for accommodating the convex edge, and the connecting part of the pole is squeezed into the sleeve hole and clamps the inner side wall with the inner wall surface of the through hole.

Preferably, the outer convex bottom surface of the post is pressed on the crimping surface of the sealing ring and is pressed with the convex edge to realize sealing, the periphery of the convex edge further comprises a concave inner ring formed by downward concave of the concave part, the surface of the concave inner ring is lower than that of the concave part, and the bottom surface of the outer side wall enters the concave inner ring for limiting.

Preferably, the welding bottom surface of the welding ring is limited in the recessed portion and is welded and fixed on the surface of the recessed portion, the extension wall is of an inclined structure, the pressing portion is formed by bending inwards from the top end of the extension wall, and the inner diameter of the pressing portion is smaller than that of the welding bottom surface.

Preferably, the pressing and holding portion includes a plurality of pressing and holding convex portions protruding inward and an avoiding groove formed between adjacent pressing and holding convex portions, the outer convex portion of the pole includes a plurality of protruding pieces protruding outward and a plurality of notches formed between adjacent protruding pieces, and after the pole is assembled into the welding ring, a gap is formed between the outer convex portion and the pressing and holding convex portions.

Preferably, the external diameter of lug is greater than press and hold the internal diameter of convex part and be less than dodge the internal diameter of groove, the lug of utmost point post corresponds dodge trench position department and pack into in the welding ring back, utmost point post rotates certain angle and makes the lug is at least partly located press and hold the convex part below, the lug with press and hold the projection of convex part in the vertical direction at least partly overlap.

Preferably, the connecting portion of the post is sleeved in the sealing ring, when the sealing ring is fixed on the convex edge outside the through hole, the post is pre-positioned and injection molded in a mold to form the insulating body, the top wall of the insulating body covers the periphery of the contact portion on the upper side of the outer convex portion and the upper side of the pressing portion, and the clamping portion comprises a first clamping portion and a second clamping portion, wherein the first clamping portion is pressed on the upper side of the outer convex portion, and the second clamping portion extends downwards from the first clamping portion and is solidified between the outer convex portion, the periphery of the sealing ring and the extending wall.

Preferably, the outer periphery of the recess is formed with a recess edge formed by downwardly recessed from the surface of the cover plate, the surface of the recess edge is higher than the surface of the recess, and the cover outer wall includes a first cover outer wall covering the outer side of the extension wall and a second cover outer wall extending from the bottom of the first cover outer wall and covering the recess edge.

Preferably, during injection molding of the insulating body, the notch outside the outer convex part corresponds to the avoiding groove at the edge of the pressing and holding part and forms a flow channel communicated from top to bottom, and the flow channel is convenient for the plastic to smoothly fill the space between the pole and the welding ring from top to bottom.

Preferably, a flow hole is formed in the extension wall in a penetrating manner, plastic flows through the flow hole and connects the covering outer wall and the clamping part into a whole, and the extension wall is wrapped between the clamping part and the covering outer wall.

This application is through the periphery in utmost point post hole sets up convex chimb and surface and is less than upwards the depressed part of chimb will welding ring welded fastening is in the depressed part the sealing washer is established to the cover on the chimb, packs into utmost point post downwards welding intra-annular and compress tightly the sealing washer realizes waterproofly, then through injection moulding insulator will utmost point post is fixed in the chimb with in the welding ring, this structural sealing performance is good, and stable in structure is firm.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

fig. 1 is a perspective assembly view of a top cover of a power battery of the present application;

fig. 2 is an exploded perspective view of a top cover of a power battery of the present application;

FIG. 3 is an enlarged view of a portion of the dotted circle shown in FIG. 2 of the top cover of the power cell of the present application;

FIG. 4 is an exploded perspective view of the terminal post, insulator, weld ring and seal ring of the power cell cap of the present application;

fig. 5 is a perspective exploded view of the terminal post, the insulator, the weld ring, and the seal ring of the power battery top cap at another angle according to the present application;

FIG. 6 is a cross-sectional view taken along line A-A of FIG. 4;

fig. 7 is a sectional view taken along the line B-B of fig. 1 and a partially enlarged view thereof.

Description of the reference numerals

An inner shell-10; an inner housing-11; a hot melt column-12; a through-hole-13; a fence-14; a liquid injection through hole-15; a cover plate-20; a plate body-21; a post hole-22; a perforation-221; a recess-222; a recessed inner ring-223; a flange-224; recessed edge-225; an inner concave ring-226; an explosion-proof port-23; a liquid injection hole-24; a plate body-25; a pole-30; a column-31; a contact portion-32; concave edge-321; an outer convex part-33; a tab-331; a notch-332; a connecting portion-34; a seal ring-40; crimping surface-41; trepan-42; an inner sidewall-43; an outer side wall-44; buckling into a groove-45; welding a ring-50; welding bottom surface-51; an extension wall-52; flow holes-521; a pressure holding part-53; a press-holding convex part-531; avoidance slot-532; -60 an insulator body; a top wall-61; a clamping portion-62; a first clamping portion-621; a lower clamp-622; covering the outer wall-63; a first cover outer wall-631; a second covering outer wall-632; a receiving slot-64; protective film-71; and (4) an explosion-proof sheet-72.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the technical solutions of the present application will be described in detail and completely with reference to the following specific embodiments of the present application and the accompanying drawings. It should be apparent that the described embodiments are only some of the embodiments of the present application, and not all of the embodiments.

In the present application, the X direction shown in fig. 1 is taken as the lateral direction, the Y direction is taken as the longitudinal direction, and the Z direction is taken as the vertical direction.

As shown in fig. 1 to fig. 3, the top cap of the power battery of the present application includes a cover plate 20 having a post hole 22, a welding ring 50 welded to the periphery of the post hole 22, a sealing ring 40 sleeved on the periphery of the upper side of the post hole 22, a post 30, an insulating body 60 integrally fixing the post 30 in the post hole 22 and the welding ring 50, and an inner shell 10 thermally fixed to the bottom surface of the cover plate 20.

The cover plate 20 includes a plate body 21, the post hole 22 formed through the plate body 21, an explosion-proof port 23, and a liquid injection hole 24. The pole post hole 22 includes a through hole 221, a concave portion 222 formed by being recessed downward from the plate body 21 and located at the outer periphery of the through hole 221, a convex edge 224 formed by being protruded upward from the periphery of the through hole 221, a concave inner ring 223 formed by being recessed downward further from the concave portion 222 around the convex edge 224, and an inner concave ring 226 formed by being recessed upward from the bottom surface of the plate body 21 around the edge of the through hole 221. The periphery of the concave portion 222 is further provided with a concave edge 225 formed by being concave from the surface of the plate body 21.

The surface of the inner concave ring 223 is lower than the top surface of the convex edge 222, and preferably the surface of the inner concave ring 223 is lower than the surface of the concave portion 222. The surface of the recessed edge 225 is higher than the surface of the recess 222. The top surface of the rim 222 is not lower than the surface of the recess 222.

The inner shell 10 comprises an inner shell 11 covering the bottom surface of the plate body 21, a through hole 13 penetrating through the inner shell 11 and corresponding to the through hole 221, a liquid injection hole 24 penetrating through a liquid injection through hole 15 of the inner shell 11, a fence 14 formed below the explosion-proof opening 23 and end parts 16 covering the two transverse sides of the plate body 21. The inner shell 11 extends upwards to form a plurality of hot-melting columns 12, a plurality of hot-melting holes (not shown) are formed in the positions, corresponding to the hot-melting columns 12, of the bottom surface of the plate body 21, and the hot-melting columns 12 stretch into the hot-melting holes to be fixed in a post-hot-melting mode. The middle position of the fence 14 is downwards sunken and is not in direct contact with the bottom side of the explosion-proof opening 23. An explosion-proof sheet 72 is welded at the bottom side of the explosion-proof opening 23, and a protective film 71 is fixed at the top of the explosion-proof opening 23.

As shown in fig. 2 to 7, the electrode posts 30 include a positive electrode post and a negative electrode post, and each of the electrode posts 30 includes a post 31, a contact portion 32 formed on an upper side of the post 31, an outer protrusion 33 formed extending from a middle portion of the post 31 along a radial direction, and a connection portion 34 formed on a lower side of the post 31. The outer convex portion 33 is located between the contact portion 32 and the connecting portion 34, the outer diameter of the contact portion 32 is smaller than the outer diameter of the outer convex portion 33, the outer diameter of the connecting portion 34 is smaller than the outer diameter of the outer convex portion 33, and preferably, the outer diameter of the connecting portion 34 is smaller than the outer diameter of the contact portion 32. The outer periphery of the top surface of the contact part 32 is recessed to form a concave edge 321, the outer periphery of the outer convex part 33 is formed with a plurality of convex pieces 331, and a plurality of notches 332 are formed between adjacent convex pieces 331. The number of the tabs 331 is not less than three, and the number of the tabs 331 of the positive and negative posts is not consistent so as to distinguish the positive and negative posts. The positive pole is made of one material, namely aluminum alloy. The negative pole column is made of two materials, namely the contact part 32 and part of the outer convex part 33 are made of aluminum alloy, the part of the outer convex part 33 and the connecting part 34 are made of copper alloy, and the contact part and the connecting part can be combined together in a friction welding mode. The reason why the two materials are selectively combined at the position of the outer convex portion 33 is that the sectional area of the outer convex portion 33 is the largest, and the combination at the outer convex portion 33 can effectively increase the combination area of the two materials and increase the combination force. In other embodiments, other bonding locations may be selected for the two materials. The outer circumference of the outer protrusion 33 has an inclined surface structure.

The welding ring 50 includes a welding bottom surface 51 attached to the surface of the recess 222, an extension wall 52 formed by extending from the inner side of the welding bottom surface 51 obliquely inward and upward, and a pressing portion 53 formed by bending inward from the top of the extension wall 52. The outer diameter of the welding bottom surface 51 is not larger than the inner diameter of the recess 222, the outer periphery of the welding bottom surface 51 is attached to the outer side of the recess 222 for accurate positioning, and the welding bottom surface 51 and the surface of the recess 222 are welded and fixed together. The extension wall 52 extends obliquely inward and upward to form an inclined wall surface, i.e., the inner diameter of the bottom portion is larger than that of the top portion. A plurality of flow holes 521 are formed through the extension wall 52. The pressing portion 53 is further formed with a plurality of pressing protrusions 531 protruding inward, and a plurality of avoiding grooves 532 are formed between adjacent pressing protrusions 531. The inner diameter at the press-holding convex part 531 is smaller than the outer diameter of the tab 331 of the outer convex part 33 of the pole post 30 and larger than the outer diameter at the notch 332. While the inner diameter at the avoidance groove 532 is larger than the outer diameter at the tab 331. So that the protruding tab 331 of the pole post 30 makes the pole post 30 enter the welding ring 50 downward when corresponding to the avoiding groove 532, and the protruding tab 331 is located below the pressing convex part 531 after the pole post 30 is rotated by a certain angle. And the projecting piece 331 at least partially overlaps the pressure-holding projection 531 in a vertical projection.

The seal ring 40 includes a crimping surface 41, a trepan 42 formed through the crimping surface 41, an inner sidewall 43 and an outer sidewall 44 respectively extending downward from both sides of the crimping surface 41 in a radial direction, and a snap-in groove 45 formed between the inner sidewall 43 and the outer sidewall 44. The vertical length of the inner side wall 43 is greater than the vertical length of the outer side wall 44. The sealing ring 40 is pressed onto the flange 224 at the periphery of the through hole 221, that is, the flange 224 is clamped into the snap-in groove 45, the outer side wall 44 extends into the concave inner ring 223, and the inner side wall 43 is attached to the inner wall surface of the through hole 221. In particular implementations, the recessed inner ring 223 may be omitted, with the outer sidewall 44 directly abutting the surface of the recess 222.

The post 30 is pressed down onto the press-contact surface 41 of the seal ring 40, and specifically, the connecting portion 34 is pressed into the through hole 221 and clamps the inner wall 43 of the seal ring 40 with the through hole 221 or the inner wall surface of the flange 224. The bottom surface of the convex portion 33 is crimped on the crimping surface 41 of the seal ring 40. The post 30 can be pre-positioned by the through hole 221 and the sealing ring 40 thereon, the contact portion 32 of the post 30 is exposed out of the top of the welding ring 50, and a gap exists between the outer convex portion 33 of the post 30 and the pressing convex portion 531 of the welding ring 50 without contacting.

The insulating body 60 includes a top wall 61 covering the upper side of the solder ring 50, a clamping portion 62 filled from the inside of the top wall 61 downward to between the solder ring 50 and the electrode post 30, a covering outer wall 63 filled from the outside of the top wall 61 downward to cover the outside of the solder ring 50, and a receiving slit 64 formed between the clamping portion 62 and the covering outer wall 63. The top wall 61 covers the upper surface of the outer protrusion 33 of the pole 30 and the surface of the pressing portion 53 of the welding ring 50, the molten plastic flows downward from the relief groove 532 of the pressing portion 53 while filling the gap between the pressing protrusion 531 and the protruding piece 331 and continues to flow downward along the notch 332, and the flow hole 521 of the extension wall 52 facilitates the plastic flow to pass through the clamping portion 62 and the covering outer wall 63 and partially connect the clamping portion and the covering outer wall 63 into a whole. The clamping portion 62 includes a first clamping portion 621 located at the upper portion and pressed on the upper surface of the external protrusion 33 of the pole post 30, and a second clamping portion 622 penetrating into the surface of the recess 222 and clamped on the outer periphery of the extended wall 52 and the pole post 30. The covering outer wall 63 includes a first covering outer wall 631 covering the outer side of the extension wall 52 and a second covering outer wall 632 covering the upper side of the welding ground 51 and the recess edge 225. The shape of the receiving slot 64 fits the shape of the extending wall 52, and is an inclined structure, when the insulating body 60 is cured, the clamping portion 62 receives the clamping force of the external convex portion 33 and the pressing portion 53 at least in the vertical direction, so that the pole 30 is fixed and limited. Meanwhile, the pressing and holding convex part 531 of the welding ring 50 and the convex part 331 of the outer convex part 33 of the pole 30 are directly and vertically stressed and clamped, and the pole 30 is stably held between the welding ring 50 and the convex edge 224 or the concave part 222.

The manufacturing method of the power battery top cover comprises the following steps:

s10, providing the cover plate 20 with the post hole 22 and the welding ring 50, and welding the welding bottom 51 of the welding ring 50 to the surface of the concave portion 222 of the post hole 22;

in this step, the welding bottom surface 51 of the welding ring 50 is attached to the surface of the recessed portion 222, and the welding ring 50 is fixed to the pole hole 22 by spot welding or other means from the upper side of the welding bottom surface 51.

S20, assembling the seal ring 40 and the pole 30 downward into the pole hole 22 and the welding ring 50;

in this step, the first assembly method is to assemble the sealing ring 40 to the flange 224 of the periphery of the post hole 22 separately and press the sealing ring 40 tightly; subsequently, the pole post 30 is pressed downwards, the connecting portion 34 of the pole post 30 is pressed into the sleeve hole 42 of the sealing ring 40 for pre-positioning, in the assembling process of the pole post 30, the protruding piece 331 of the outer protruding portion 33 of the pole post 30 corresponds to the avoiding groove 532 of the pressing and holding portion 53, so that the protruding piece 331 of the pole post 30 avoids the pressing and holding protruding portion 531 of the pressing and holding portion 53 to enter the welding ring 50, the pole post 30 is rotated by a certain angle to enable the protruding piece 331 to move to the lower portion of the pressing and holding protruding portion 531, and finally, the connecting portion 34 of the pole post 30 is pre-fixed in the sleeve hole 42 of the sealing ring 40.

The second assembly mode is that the sealing ring 40 is sleeved on the periphery of the connecting part 34 of the pole 30; then, the combination of the pole 30 and the sealing ring 40 is pressed into the welding ring 50, and the snap-in groove 45 of the sealing ring 40 is wrapped on the convex edge 224 of the periphery of the through hole 221. In the same manner as above, the protruding piece 331 of the external protrusion 33 is made to correspond to the avoiding groove 532 of the pressing and holding portion 53 to make the pole 30 smoothly enter the welding ring 50, and then the combination of the pole 30 and the sealing ring 40 is rotated by a certain angle to make the protruding piece 331 located below the pressing and holding protrusion 531; finally, the combination of the pole 30 and the sealing ring 40 is pressed down, so that the snap-in groove 45 of the sealing ring 40 is wrapped on the convex edge 224 of the periphery of the through hole 221.

S30, carrying out in-mold injection molding on the combination of the cover plate 20 welded with the welding ring 50, the pole 30 and the sealing ring 40 to form the insulating body 60; the insulating body 60 fixes the pole 30 between the flange 224 of the pole hole 22 and the pressing part 53 of the welding ring 50;

in this step, the molten plastic infiltrates the outside of the post 30 and the inside and outside of the welding ring 50 are solidified, and the insulating body 60 includes a top wall 61 covering the upper side of the external convex portion 33 of the post 30 and the upper side of the pressing portion 53, a connection portion connecting the top wall 61 and solidifying in the clamping portion 62 between the periphery of the post 30 and the extending wall 52 and a covering outer wall 63 covering the outer surface of the welding ring 50.

In an embodiment, only the upward convex edge 224 is remained on the periphery of the post hole 22, and the concave portion 222 is eliminated, the upper surface of the plate body 21 is directly used as a plastic bonding surface, and the top of the convex edge 224 is higher than the upper surface of the plate body 21, which is not the optimal solution, which causes positioning difficulty in welding the welding ring 50, and increases the height of the post 30 protruding from the plate body 21, which affects the appearance, but if the manufacturing process is accurate enough, the embodiment is still one of the options.

This application is through the periphery in utmost point post hole 22 sets up convex chimb 224 that makes progress the chimb 224 periphery welded fastening welding ring 50 the sealing washer 40 is established to the cover on chimb 224, packs into utmost point post 30 downwards in the welding ring 50 and compress tightly sealing washer 40 realizes waterproofly, then through injection moulding insulator 60 will utmost point post 30 is fixed in chimb 224 with in the welding ring 50, this structural sealing performance is good, and stable in structure is firm.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above examples only express preferred embodiments of the present invention, and the description thereof is more specific and detailed, but not to be construed as limiting the scope of the utility model. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A power battery top cover is characterized by comprising a cover plate provided with a pole column hole, a welding ring welded on the periphery of the pole column hole, a sealing ring, a pole column and an insulating body for integrally forming and fixing the pole column in the pole column hole and the welding ring, wherein the pole column hole comprises a through hole, a concave part formed on the periphery of the through hole from the surface of the cover plate in a concave way and a convex edge formed by upwards protruding from the edge of the concave part, the sealing ring is sleeved on the convex edge, the pole column comprises a column body, a contact part formed on the upper part of the column body, a connecting part formed on the lower part of the column body and sleeved in the sealing ring and an outer convex part formed by extending from the middle of the column body along the radial outer side and abutting against the sealing ring, the welding ring comprises a welding bottom surface fixed in the concave part by welding, an extending wall formed by extending from the inner side of the welding bottom surface to the inner upper part in an inclined way and a pressing part formed by inwards bending from the top of the extending wall, the insulating body comprises a top wall, a clamping part and a covering outer wall, wherein the clamping part is connected with the top wall and is solidified between the pole and the welding ring, and the covering outer wall is connected with the top wall and covers the outer side of the welding ring.

2. The top cover of the power battery as claimed in claim 1, wherein the top of the convex edge is higher than the surface of the concave portion, the sealing ring comprises a compression joint surface located on the upper side of the convex edge, a sleeve hole formed through the compression joint surface and used for the connection portion of the post to be sleeved in, an inner side wall formed by extending downwards from the inner side and the outer side of the compression joint surface, an outer side wall and a buckling groove formed between the inner side wall and the outer side wall and used for accommodating the convex edge, and the connection portion of the post is squeezed into the sleeve hole and clamps the inner side wall with the inner wall surface of the through hole.

3. The top cap of claim 2, wherein the bottom surface of the external protrusion of the post is pressed against the press-fit surface of the sealing ring and is sealed with the flange pressing against the press-fit surface, the periphery of the flange further comprises a recessed inner ring recessed downward from the recessed portion, the surface of the recessed inner ring is lower than the surface of the recessed portion, and the bottom surface of the outer sidewall is limited in the recessed inner ring.

4. The top cover of power battery as claimed in claim 1 or 3, wherein the welding bottom surface of the welding ring is limited in the recess and is welded and fixed on the surface of the recess, the extension wall is of an inclined structure, the pressing part is formed by bending inwards from the top end of the extension wall, and the inner diameter of the pressing part is smaller than that of the welding bottom surface.

5. The top cover of the power battery as claimed in claim 4, wherein the pressing portion includes a plurality of pressing protrusions protruding inward and a plurality of relief grooves formed between adjacent pressing protrusions, the outer protrusion of the post includes a plurality of protruding tabs protruding outward and a plurality of recesses formed between adjacent protruding tabs, and after the post is assembled into the welding ring, a space exists between the outer protrusion and the pressing protrusions.

6. The top cover of the power battery as claimed in claim 5, wherein the outer diameter of the protruding piece is larger than the inner diameter of the pressing and holding convex portion and smaller than the inner diameter of the avoiding groove, after the protruding piece of the pole is installed into the welding ring at the position corresponding to the avoiding groove, the pole is rotated by a certain angle to enable the protruding piece to be at least partially located below the pressing and holding convex portion, and the projection of the protruding piece and the pressing and holding convex portion in the vertical direction is at least partially overlapped.

7. The top cap of claim 6, wherein the connecting portion of the post is inserted into the sealing ring, and when the sealing ring is fixed to the rim outside the through hole, the post is pre-positioned and injection molded to form the insulating body, the top wall of the insulating body covers the outer periphery of the contact portion on the upper side of the outer protrusion and the upper side of the pressing portion, and the clamping portion includes a first clamping portion pressed above the outer protrusion and a second clamping portion extending downward from the first clamping portion and solidified between the outer protrusion, the outer periphery of the sealing ring, and the extending wall.

8. The top cover for power battery as claimed in claim 7, wherein the periphery of the recess is formed with a recess edge recessed downward from the surface of the cover plate, the surface of the recess edge is higher than the surface of the recess, and the cover outer wall includes a first cover outer wall covering the outside of the extension wall and a second cover outer wall extending from the bottom of the first cover outer wall and covering the recess edge.

9. The top cap of claim 6, wherein the recess on the outer side of the external protrusion corresponds to the avoiding groove on the edge of the pressing portion and forms a flow channel which is communicated with the upper portion and the lower portion, and the flow channel facilitates smooth filling of plastic in the space between the terminal post and the welding ring from top to bottom.

10. The top cap of claim 9, wherein a flow hole is formed through the extension wall, through which plastic flows to connect the cover outer wall and the clip together, and the extension wall is wrapped between the clip and the cover outer wall.