CN117219932A - Injection molding type top cover of secondary battery, secondary battery and manufacturing method of secondary battery - Google Patents

Abstract

The invention discloses an injection molding type top cover of a secondary battery, which comprises a base plate, a stop rack, a pole and an upper plastic part, wherein the stop rack is arranged on the base plate; the first surface of the substrate is provided with a convex ring structure surrounding the periphery of the pole mounting hole, and the convex ring structure is non-circular; a plurality of substrate through grooves are arranged in the injection molding area between the convex ring structure and the pole mounting hole at intervals; the sinking platform is provided with an annular convex groove which extends downwards and is communicated with the substrate through groove; an explosion-proof valve is arranged in the explosion-proof valve mounting hole in a sealing way; the stop frame is positioned below the base plate; the upper plastic part is an integrally formed injection molding part and coats the columnar body and the convex ring structure in an injection molding mode; the invention also includes a secondary battery and a method of manufacturing the same. The beneficial effects of the invention are as follows: the thrust resistance and the torsion resistance of the pole are improved, the air tightness problem in the use process of the pole is effectively improved, the reliability of the system is improved, and the pole is prevented from falling down.

Description

Injection molded top cover of secondary battery, secondary battery and production method thereof

Technical field

The invention belongs to the field of secondary batteries, and more specifically, relates to an injection molded top cover of a secondary battery, a secondary battery and a manufacturing method thereof.

Background technique

Secondary batteries, also known as rechargeable batteries or storage batteries, refer to batteries that can be recharged to activate active substances and continue to be used after the battery is discharged. It is in high demand in industries such as electric vehicles and power tools and is a related product. Important components in the product have a direct impact on the performance of related products. Secondary batteries usually include a casing, a battery core and a top cover. The battery core is located in the casing and is encapsulated by the top cover. The top cover includes a top base plate and poles arranged on the top substrate. The poles are connected to the tabs of the cell. Use At this time, the pole is connected to an external electrical device for power supply or connected to an external power source for charging.

The initial process used for the secondary battery top cover was to directly assemble it by welding or riveting. In this method, the waste residue generated during the welding or riveting process easily falls into the battery cells, increasing the risk of short circuits, and the installation process is complex and time-consuming. It will affect the assembly efficiency of secondary batteries, thus increasing the cost of raw materials and manufacturing costs. In response to the above defects, a new assembly method was designed, that is, direct one-piece injection molding is used to assemble the poles and the top substrate. However, currently Some injection molded parts are mostly top-covered with the substrate. Injection molded parts under this matching method are prone to rupture and breakage when the pole part is subjected to thrust and torsion, causing the sealing ring and pole to loosen, affecting the pole. The air tightness and reliability of the lithium battery bring adverse risks; and the use of injection-molded poles, due to the physical differences between the metal top substrate and poles and the injection-molded polymer plastic, the one-piece top cover after injection molding is at high In application environments such as low temperature or long-term aging, the fixing strength between the injection molded parts and the poles is insufficient, and the poles and the top substrate are detached from each other and the poles collapse, thus affecting the stability of the top cover and pole structures. properties and positioning strength, reducing the reliability of secondary batteries.

Therefore, there is an urgent need for a secondary battery injection molded top cover, a secondary battery and a manufacturing method thereof that can solve the above problems.

Contents of the invention

In view of the above shortcomings, the purpose of the present invention is to provide an injection-molded top cover for a secondary battery and a secondary battery. The present invention enhances the connection strength between the components through the integrated design of the upper plastic part, the substrate, and the pole. The large fixing strength effectively improves the air tightness problem during the use of the pole, and through the special connection structure of the upper plastic part, base plate, and pole, it effectively prevents the pole from settling during use and improves the performance of the pole. The anti-thrust and anti-torsion capabilities improve product performance and reliability.

The technical solutions adopted by the present invention to achieve the above objects are:

An injection-molded top cover for a secondary battery, which is characterized in that it includes a base plate, a stopper, a pole and an upper plastic part;

The base plate has an upper surface and a lower surface arranged oppositely along the thickness direction of the base plate. The base plate is provided with pole mounting holes, sealable liquid injection holes, and explosion-proof valve mounting holes. The upper surface of the base plate is provided with surrounding The convex ring structure around the pole mounting hole is non-circular; there is an inner injection molding area between the convex ring structure and the pole mounting hole on the upper surface, so There are several substrate through-grooves spaced apart in the inner injection molding area, and the bottom of the substrate is provided with an annular convex groove extending downward, and the annular convex groove is connected with each of the substrate through-grooves; the explosion-proof valve mounting hole An explosion-proof valve is installed in the middle seal;

The stopper frame is located below the base plate, and the stopper frame is provided with pole holes;

The poles are inserted through the pole holes and the pole installation holes from bottom to top. A seal is provided between the bottom of the pole and the stop frame. The top of the pole extends to the top of the base plate, and There is an injection molding gap between the pole and the base plate;

The upper plastic part is an integrally formed injection molded part, and the upper plastic part covers the columnar body and the convex ring structure through injection molding. When the upper plastic part is injection molded, the outer injection molding area formed by the plastic filling mold and the convex ring structure, the inner injection molding area defined by the convex ring structure and the pole, the pole mounting hole and the injection gap defined by the pole, and the injection molding gap defined on the base plate. Base plate through groove and annular convex groove.

Further, the substrate has an upper surface and a lower surface that are oppositely arranged along the thickness direction of the substrate. The substrate is provided with pole mounting holes, sealable liquid injection holes, and explosion-proof valve mounting holes that penetrate the upper surface and the lower surface.

Furthermore, an inner injection molding area is left on the upper surface between the convex ring structure and the pole mounting hole, and several substrate through-grooves are spaced apart in the inner injection molding area.

Further, the pole includes an end plate and a cylindrical body arranged on the end plate. The end plate is non-circular and is located below the stop frame; the cylindrical body passes upward through the aligned pole holes in sequence. , the pole mounting hole extends to the top of the base plate, and there is an injection molding gap between the outer peripheral wall of the cylindrical body and the inner hole wall of the pole mounting hole, and the outer peripheral wall of the cylindrical body and the pole There is an annular gap for accommodating a sealing member between the inner hole walls of the column hole. The sealing member is sleeved on the columnar body, and the sealing member is located in the annular gap between the top surface of the end plate and the lower surface of the base plate. within the gap.

Further, the lower surface is provided with a sinking platform opposite to the inner injection molding area.

Furthermore, each of the substrate through-grooves penetrates the upper surface and the sinking platform; an annular convex groove extending downward is provided on the sinking platform, and the annular convex groove communicates with each of the substrate through-grooves.

Further, the cross section of the convex ring structure is annular, the inner edge of the annular shape is hexagonal, and the outer edge of the annular shape is triangular.

Further, the stopper frame has a first surface and a second surface that are oppositely arranged along the thickness direction of the stopper frame, and the stopper frame is provided with a pole hole penetrating the first surface and the second surface; the stopper frame The second surface of the frame is provided with an end plate receiving groove surrounding the pole hole, the outer contour of the end plate is adapted to the end plate receiving groove, and the cross section of the end plate receiving groove and the end plate All are triangles.

Further, the upper top surface of the convex ring structure is provided with several injection molding grooves at intervals. When the upper plastic part is injection molded, plastic is filled in the injection molding grooves.

Further, the bottom end of the annular convex groove is flush with the lower surface of the base plate, the annular convex groove is a tapered groove with an opening facing downward, and the width of the opening of the tapered groove is greater than the width of the bottom of the tapered groove. .

Further, the end plate is provided with a sealing groove surrounding the columnar body, a sealing member is installed in the sealing groove, the sealing member abuts against the bottom end of the annular convex groove, and the sealing member is The inner annular wall abuts against the outer peripheral wall of the columnar body.

Further, the sealing member is an annular sealing ring, the upper annular surface of the sealing member is provided with an annular groove, the lower annular surface of the sealing member is provided with a boss flange, and the boss flange is embedded in the sealing groove. .

Further, the columnar body and the upper plastic part are fixed in a concave-convex manner.

Furthermore, the outer peripheral wall of the cylindrical body is provided with an annular groove, and the upper plastic part is provided with a convex ring correspondingly. The convex ring is inserted into the annular groove to limit the upper and lower movement of the upper plastic part relative to the cylindrical body. move.

A secondary battery according to the present invention includes a casing, and the casing is provided with an opening. It is characterized in that the injection-molded top cover of the secondary battery is installed in the opening.

The assembly method of the secondary battery according to the present invention proceeds as follows:

Step 1. Assemble the explosion-proof valve into the installation hole of the explosion-proof valve on the base plate, and ensure the seal between the explosion-proof valve and the installation hole of the explosion-proof valve;

Step 2. First assemble the seal on the pole. The boss flange of the seal is embedded in the sealing groove of the pole. The seal is tightly fixed in the sealing groove of the end plate to prevent its displacement when compressed. , causing the pole to tilt;

Step 3. Put the assembled seal, pole, and stop frame into the injection mold in sequence, keeping the pole mounting hole aligned with the pole hole. At this time, the columnar body of the pole passes upward through the aligned pole hole. , the pole mounting hole extends to the top of the base plate until the top surface of the end plate abuts the second surface of the stop frame. At this time, the annular groove at the bottom of the base plate abuts the bottom surface of the annular groove of the seal. ;

Step 4. After assembly, the corresponding upper plastic part is injection molded as a whole through the mold. When the upper plastic part is injection molded, the plastic fills the outer injection molding area formed by the mold and the convex ring structure, and the inner injection molding area defined by the convex ring structure and the pole. The injection molding gap defined by the pole mounting hole and the pole, the substrate through-groove and the annular convex groove provided on the substrate realize an integrated secondary battery injection molded top cover between the upper plastic part, pole, substrate and stopper. ;

Step 5: Seal the injection-molded top cover of the secondary battery to the opening of the secondary battery casing, and inject the electrolyte. After the liquid injection is completed, install a plug seal at the liquid injection hole to complete the package.

The injection-molded top cover of the secondary battery of the present invention is provided with an outer triangular and inner hexagonal convex ring structure. The upper plastic part is injection molded into a structure adapted to the convex ring structure. The upper plastic part is wrapped around the outside of the convex ring structure and filled with In the injection molding gap between the pole and the pole mounting hole, since the upper plastic part and the convex ring structure adopt an outer triangular inner hexagonal non-circular structure, the bonding between the upper plastic part and the base plate is greatly improved. , thereby significantly improving the thrust and torsion resistance of the pole; in addition, when the upper plastic part is injection molded, the plastic part is also filled in the inner injection molding area, the substrate through-groove and the annular convex groove to form a connection structure that penetrates the substrate , the connection method between the base plate and the upper plastic part is designed as a through-type mechanical locking method, combined with the non-circular outline of the convex ring structure, which greatly improves the firmness of the connection between the upper plastic part and the base plate, thereby significantly improving the resistance of the pole. Thrust and torque resistance.

Advantageously, an annular convex groove is provided at the bottom of the base plate. Since the annular convex groove is a tapered groove with a large mouth and a small bottom, the upper plastic part is injected from above during injection molding, and the plastic is filled into the inner injection molding area and the base plate through-groove. , annular convex groove, and the injection molding gap, the upper plastic part and the sealing part are finally in contact, that is, the injection molded upper plastic part can partially penetrate the base plate, so that the base plate is fixed with the pole post and sleeved on the pole under the fixation of the upper plastic part. The seals of the pole are integrated, which greatly strengthens the installation strength of the pole, thereby improving the thrust and torsion strength of the pole, avoiding damage and cracking caused by stress concentration at the connection between the upper plastic part and the base plate, and improving the air tightness and reliability, and also directly improves the energy density of the pole.

More advantageously, the lower ring surface of the seal is provided with a boss flange, and the boss flange is embedded in the sealing groove on the end plate of the pole, thereby fixing the position of the seal and preventing pressure from being generated during injection molding of the upper plastic part. This causes side deflection and tilt of the pole, so that the injection molded part can always closely cooperate with the pole and the seal set on the pole during injection molding, thereby improving the connection strength between the injection molded part, the substrate and the pole.

The outer peripheral wall of the columnar body of the pole of the present invention is also provided with an annular groove. The upper plastic part is injected from above during injection molding. In addition to filling the inner injection molding area, the substrate through-groove, the annular convex groove, and the injection gap, the plastic In addition, the annular groove will also be filled, thereby effectively limiting the upward and downward movement of the upper plastic part relative to the columnar body, improving the bonding strength between the upper plastic part and the pole, and effectively preventing the pole from falling down during use.

The beneficial effects of the present invention are:

1) Improve the air tightness and reliability of the pole: through the integrated design of the upper plastic part, the substrate, and the pole, the connection strength is increased, which can effectively improve the air tightness problem during the use of the pole and improve the reliability of the system;

2) Prevent the pole from falling down: The filling design between the upper plastic part, the convex ring structure, and the annular convex groove can effectively prevent the pole from falling down during use;

3) Improve the thrust resistance of the pole: The through-type mechanical locking design of the upper plastic part and the base plate can significantly increase the thrust force of the pole;

4) Improve the torsion resistance: The upper plastic part adopts a triangular design and a through design to improve the torsion resistance.

Description of drawings

Figure 1 is a structural diagram of the injection molded top cover of a secondary battery of the present invention.

Figure 2 is a front view of the injection molded top cover of the secondary battery of the present invention.

Figure 3 is a bottom view of the injection molded top cover of the secondary battery of the present invention.

Figure 4 is one of the structural diagrams of the substrate of the present invention.

Figure 5 is the second structural diagram of the substrate of the present invention.

Figure 6 is an enlarged view of C in Figure 4, showing the boss structure.

Figure 7 is one of the structural diagrams of the stopper frame of the present invention.

Figure 8 is the second structural diagram of the stopper frame of the present invention.

Figure 9 is a structural diagram of the pole of the present invention.

Figure 10 is one of the structural diagrams of the seal of the present invention.

Figure 11 is the second structural diagram of the seal of the present invention.

Figure 12 is one of the structural diagrams of the upper plastic part of the present invention.

Figure 13 is the second structural diagram of the upper plastic part of the present invention.

Fig. 14 is a cross-sectional view taken along line A-A in Fig. 4 .

Fig. 15 is a B-B cross-sectional view of Fig. 4 .

FIG. 16 is an enlarged view of D in FIG. 15 .

Figure 17 is an exploded view of the injection molded top cover of the secondary battery of the present invention.

Figure 18 is a structural diagram of the present invention with the upper plastic part removed, showing the positional relationship between the pole and the base plate.

Fig. 19 is a structural diagram of the secondary battery of the present invention.

Specific implementation methods

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention and cannot be understood as limiting the present invention.

In the description of the present invention, it should be understood that the terms "upper", "lower", "left", "right", "inner", "outer", "axial", "circumferential", etc. indicate an orientation. Or the positional relationship is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. , therefore cannot be construed as a limitation of the present invention. In addition, features defined as “first” and “second” may explicitly or implicitly include one or more of these features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

In the description of the present invention, it should be noted that, unless otherwise clearly stated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection. Connection, or integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood on a case-by-case basis.

The present invention will be further described below with reference to specific embodiments, but the protection scope of the present invention is not limited thereto. It should be noted that the secondary battery is usually placed vertically, with the pole on the top cover of the secondary battery extending out to connect to the outside world on one side, and on the other side, the bottom. In addition, although the pole 3 in the illustrated embodiment has both positive and negative poles disposed on the injection-molded top cover of the secondary battery, in other embodiments, only one positive and negative pole assembly may be disposed on the injection molded top cover of the secondary battery. The injection molded top cover of the secondary battery does not affect the implementation of the present invention. Since the present invention does not involve the polarity distinction between positive and negative poles, the polarities of the poles and the like are no longer described.

The injection-molded top cover of a secondary battery according to the invention includes a base plate 1, a stopper 2, a pole 3 and an upper plastic part 4;

The base plate 1 has an upper surface and a lower surface arranged oppositely along the thickness direction of the base plate. The base plate 1 is provided with pole mounting holes 11 penetrating the upper surface and lower surface, a sealable liquid injection hole 12, and an explosion-proof valve mounting hole. 13. The upper surface of the base plate 1 is provided with a convex ring structure 14 surrounding the pole mounting hole 11. There is an inner injection molding area between the convex ring structure 14 and the pole mounting hole 11, so The lower surface is provided with a sinking platform opposite to the inner injection molding area. The inner injection molding area is provided with several substrate through-grooves 15 at intervals, and each of the substrate through-grooves 15 penetrates the upper surface and the sinking platform; An annular convex groove 16 extending downward is provided on the sinking platform, and the annular convex groove 16 is connected with each of the substrate through-grooves 15; the explosion-proof valve 5 is sealed and installed in the explosion-proof valve mounting hole 13;

The stopper frame 2 is located below the base plate 1, and the stopper frame 2 is provided with a pole hole 21 penetrating the first surface and the second surface;

The pole 3 is inserted into the pole hole 21 and the pole installation hole 11 from bottom to top. A seal 33 is provided between the bottom of the pole 3 and the stop frame 2. The top of the pole 3 extends to Above the substrate 1, there is an injection molding gap between the pole 3 and the substrate 1;

The upper plastic part 4 is an integrally formed injection molded part, and the upper plastic part 4 covers the columnar body 32 and the convex ring structure 14 through injection molding. When the upper plastic part 4 is injection molded by a mold, the mold is filled with plastic. The outer injection molding area formed with the convex ring structure, the inner injection molding area defined by the convex ring structure 14 and the pole, the pole mounting hole and the injection molding gap defined by the pole, the substrate through groove 15 and the annular convex groove 16 provided on the substrate.

In some embodiments of the present invention, the pole 3 includes an end plate 31 and a columnar body 32 provided on the end plate 31. The end plate 31 is non-circular and is located below the stop frame 2; The columnar body 32 passes upward through the aligned pole holes 21 and pole mounting holes 11 and extends to the top of the base plate 1 , and the outer peripheral wall of the columnar body 32 is in contact with the inner hole of the pole mounting hole 11 . An injection molding gap is left between the walls, and an annular gap is left between the outer peripheral wall of the columnar body 32 and the inner hole wall of the pole hole 21 to accommodate the sealing member 33. The sealing member 33 is sleeved on the columnar body 32. on the top, and the seal 33 is located in the annular gap between the top surface of the end plate 31 and the lower surface of the base plate 1 .

In some embodiments of the present invention, the convex ring structure 14 is non-circular, that is, the cross section of the convex ring structure 14 is a non-circular annular shape, the inner edge of the annular shape is hexagonal, and the outer edge of the annular shape is triangular. . The upper plastic part 4 is injection molded into a structure that fits the raised ring structure 14. The upper plastic part 4 is wrapped around the raised ring structure 14 and filled in the space between the pole 3 and the raised ring structure 14. Since the upper plastic part 4 Both the outer triangular inner hexagonal non-circular structure and the convex ring structure 14 adopt a non-circular structure with an outer triangle and an inner hexagon, and are combined with the base plate through-groove 11 provided on the base plate 1 to form a through-type mechanical locking design. 1 is firmly combined to prevent twisting between the upper plastic part 4 and the base plate 1, significantly improve the thrust and torsion resistance of the pole, and prevent the upper plastic part 4 from breaking due to the thrust and torsion of the pole. and breakage problems, effectively preventing the seals and poles from loosening, significantly improving the airtightness and reliability of the poles, and avoiding the problem of adverse risks in lithium batteries due to airtightness. In addition, the smooth transition of the rounded corners at the connection between the inner edge of the hexagon and the outer edge of the triangle can prevent injection dead corners during injection molding and produce plastic gaps that will affect the injection molding effect. It can also prevent the upper plastic parts from resisting distortion force without affecting the injection molding effect. It will cut the upper plastic parts and better ensure the integrity of the upper plastic parts.

In other embodiments of the present invention, the inner side of the annular shape includes three first sides and three second sides, wherein the three first sides and three second sides are alternately connected end to end, and the third The length of one side is less than the length of the second side. The second side corresponds to and is parallel to the three sides of the triangle, and each of the first sides is arranged opposite to a vertex angle of the triangle.

In some embodiments of the present invention, the stopper frame 2 has a first surface and a second surface that are oppositely arranged along the thickness direction of the stopper frame, and the stopper frame 2 is provided with a first surface and a second surface that pass through the first surface and the second surface. Pole hole 21.

In some embodiments of the present invention, the second surface of the stopper 2 is provided with an end plate receiving groove 22 surrounding the pole hole 21, and the outer contour of the end plate 31 is adapted to the end plate receiving groove. . The cross sections of the end plate receiving groove 22 and the end plate 31 are both triangular, so that when the pole is inserted into the pole hole 21, the end plate 31 can be embedded in the end plate receiving groove of the stop frame. The plate is triangular in shape, which can effectively prevent the relative rotation between the pole and the stop frame. Combined with the joint action of the upper plastic part and the convex ring structure, the torsion resistance of the pole is greatly enhanced.

In some embodiments of the present invention, the inner injection molding area is provided with three substrate through grooves 15 at intervals, and the three substrate through grooves 15 are provided between the first side and the triangle vertex. The substrate through grooves 15 are Straight grooves, arc-shaped grooves or other forms of through-grooves, preferably arc-shaped grooves, the depressions of the arc-shaped grooves face the columnar body, and the three substrate through-grooves 15 are evenly distributed around the columnar body 32 . The advantage of the arc-shaped groove is that it can strengthen the bonding strength between the upper plastic part and the cover plate during injection molding. It has a better bonding effect than ordinary straight grooves or injection molding holes, and can effectively prevent the gap between the upper plastic part and the convex ring structure of the base plate. Twists occur, affecting the use of the pole.

In some embodiments of the present invention, the upper top surface of the convex ring structure 14 is provided with several injection molding grooves 141 at intervals. When the upper plastic part 4 is injection molded, plastic is filled in the injection molding grooves 141 . The injection molding groove 141 can be a special-shaped groove with an open top, or a sunken shallow groove with an open top, which facilitates the rapid flow of plastic, increases the bonding points between the base plate and the upper plastic part, and prevents the occurrence between the upper plastic part and the base plate. Relative movement improves the torsion resistance of the upper plastic parts.

In other embodiments of the present invention, the bottom surface of the injection molding groove 141 is flush with the upper surface of the base plate 1. During injection molding, plastic parts can be filled in the injection molding groove 141 at the same time to strengthen the relationship between the upper plastic parts and the base plate. connections between. The upper plastic part 4 covers the convex ring structure during injection molding and surrounds the outer periphery of the columnar body. The top surface of the columnar body remains exposed to facilitate connection with the outside world.

In some embodiments of the present invention, the bottom end of the annular convex groove 16 is flush with the lower surface of the substrate 1 , and the annular convex groove 16 is a tapered groove with a large opening and a small bottom, that is, The width of the groove opening of the tapered groove is greater than the width of the groove bottom of the tapered groove. The advantage of this structure is that the upper plastic part is injected from above during injection molding, and part of the plastic passes through the base plate through groove 15 and the annular convex groove 16 in sequence and then is connected to the seal. 33 surface contact, since the annular convex groove is a tapered groove with a large mouth and a small bottom, the through-type mechanical locking design of the upper plastic part 4 and the base plate 1 can prevent the upper plastic part 4 from detaching from the base plate 1, and can significantly improve the pole. The thrust force exerted on 3 strengthens the connection strength between the upper plastic part 4 and the base plate 1, thereby improving the thrust resistance and torsion strength of the pole, avoiding damage and cracking caused by stress concentration at the connection between the upper plastic part and the base plate, and improving the pole The air tightness and reliability of the pole also directly increase the energy density of the pole. The cross-section of the annular groove 16 in this application is not limited to a tapered groove, and any other cross-section that can achieve this function can be used.

In some embodiments of the present invention, the end plate 31 is provided with a sealing groove 311 surrounding the columnar body 22 , and a sealing member 33 is installed in the sealing groove 311 . The sealing member 33 is connected with the annular body 22 . The bottom end of the convex groove 16 abuts, and the inner annular wall of the seal 33 abuts the outer peripheral wall of the columnar body 22 .

In some embodiments of the present invention, the sealing member 33 is an annular sealing ring, the upper annular surface of the sealing member 33 is provided with an annular groove 331, and the lower annular surface of the sealing member 33 is provided with a boss method. The flange 332 and the boss flange 332 are embedded in the sealing groove 311 to prevent the pressure generated during injection molding of the upper molded part from causing side deflection and tilting of the pole, so that the injection molded part can be sealed with the pole and the pole set on the pole during injection molding. The parts are always closely matched to improve the connection strength between the injection molded parts, the substrate and the poles.

In some embodiments of the present invention, the columnar body 32 and the upper plastic part 4 are fixed in a concave-convex fitting manner.

In some embodiments of the present invention, the outer peripheral wall of the columnar body 32 is provided with an annular groove 321. The upper plastic part is injected from above during injection molding. The plastic is filled into the inner injection molding area, the substrate through-groove, and the annular groove. In addition to the convex groove and the injection molding gap, the annular groove will also be filled, and a convex ring 41 adapted to the annular groove 321 is formed on the upper plastic part. The convex ring 41 is inserted into the annular groove 321 in an adapted form. To limit the upward and downward movement of the upper plastic part 4 relative to the columnar body 32, the fixation firmness of the pole and the upper plastic part is improved, thereby improving the stability of fixing the pole on the base plate, and effectively preventing the pole from falling down during use. . In practical applications, the upper plastic part 4 can also be assembled using deformable materials, or can be formed by other common methods such as extrusion, hot melting, etc., but is not limited thereto.

In other embodiments of the present invention, the outer peripheral wall of the columnar body 32 is provided with protrusions, and the upper plastic part 4 is provided with a corresponding groove, and the protrusions are inserted into the recesses in an adapted manner. in the groove to limit the upward and downward movement of the upper plastic part 4 relative to the columnar body 32 .

On the premise that no conflict occurs, those skilled in the art can freely combine and superimpose the above additional technical features.

A secondary battery according to the present invention includes a housing 6. The housing 6 is provided with an opening, and the injection molded top cover of the secondary battery is installed in the opening.

The assembly method of the secondary battery according to the present invention proceeds as follows:

Step 1. Assemble the explosion-proof valve 5 into the explosion-proof valve mounting hole 13 of the base plate 1, and ensure the seal between the explosion-proof valve 5 and the explosion-proof valve mounting hole 13;

Step 2: First assemble the seal 33 on the pole 3. The boss flange 332 of the seal 33 is embedded in the sealing groove 311 of the pole 3. The seal 33 is tightly fixed at the sealing groove of the end plate. , which can not only play a sealing role, but also prevent displacement during compression, causing the pole 3 to tilt;

Step 3. Place the assembled seal 33, the pole, the stopper, and the assembled base plate 1 of the explosion-proof valve 5 into the injection mold in sequence from bottom to top, keeping the pole mounting hole 11 aligned with the pole hole 21. At this time, the columnar body of the pole 3 extends upward through the aligned pole holes and pole mounting holes 11 to the top of the base plate 1 until the top surface of the end plate abuts the second surface of the stop frame. When the annular convex groove at the bottom of the base plate abuts the bottom surface of the annular groove of the seal;

Step 4. After assembly, the corresponding upper plastic part 4 is injection molded as a whole through the mold. When the upper plastic part 4 is injection molded, plastic is filled inside, and the outer injection molding area, the convex ring structure and the pole are formed by the plastic filling mold and the convex ring structure. The inner injection molding area defined by the pole, the pole mounting hole and the injection molding gap defined by the pole, the substrate through-groove and the annular convex groove provided on the base plate 1 realize the integration between the upper plastic part, the pole, the base plate and the stop frame Injection molded top cover of secondary battery;

Step 5: Seal the injection-molded top cover of the secondary battery to the opening of the secondary battery casing, and inject the electrolyte. After the liquid injection is completed, install the sealing plug 121 at the liquid injection hole 12 for sealing.

In the description of this specification, reference to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" or the like is intended to be incorporated into the description of the implementation. An example or example describes a specific feature, structure, material, or characteristic that is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art will appreciate that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and purposes of the invention. The scope of the invention is defined by the claims and their equivalents.

Claims (10)

1. The utility model provides a secondary cell top cap of moulding plastics which characterized in that: the anti-explosion device comprises a substrate (1), a stop frame (2), a pole (3) and an upper plastic part (4), wherein a pole mounting hole (11), a liquid injection hole (12) and an anti-explosion valve mounting hole (13) are formed in the substrate (1), a convex ring structure (14) encircling the periphery of the pole mounting hole (11) is arranged on the upper surface of the substrate (1), the convex ring structure (14) is non-circular, and a plurality of substrate through grooves (15) are formed between the convex ring structure (14) and the pole mounting hole (11) at intervals; the bottom of the base plate (1) is provided with an annular convex groove (16) communicated with each base plate through groove (15); the stop frame (2) is arranged below the base plate (1); the pole (3) is sequentially arranged in the pole hole (21) and the pole mounting hole (11) of the stop frame (2) in a penetrating manner from bottom to top, and the bottom of the pole (3) is sealed with the stop frame (2); the upper plastic part (4) is an integrally formed injection molding part, and the upper plastic part (4) is used for coating the pole (3) and the convex ring structure (14) in an injection molding mode.

2. The injection molded top cap for a secondary battery according to claim 1, wherein: the cross section of the convex ring structure (14) is annular, the inner edge of the annular shape is hexagonal, and the outer edge of the annular shape is triangular; the stop frame (2) is provided with a first surface and a second surface which are oppositely arranged along the thickness direction of the stop frame, and a pole hole (21) penetrating through the first surface and the second surface is arranged on the stop frame (2); the second surface of the stop frame (2) is provided with an end plate accommodating groove encircling the periphery of the pole hole (21), the outer contour of the end plate (31) is matched with the end plate accommodating groove, and the cross sections of the end plate accommodating groove and the end plate are triangular.

3. The injection molded top cap for a secondary battery according to claim 2, wherein: the upper top surface of bulge loop structure (14) is equipped with a plurality of injection molding groove (141) at intervals, when going up plastic part (4) injection molding, the plastic is filled in injection molding groove (141).

4. The injection molded top cap for a secondary battery according to claim 1, wherein: the bottom of the annular convex groove (16) is flush with the lower surface of the base plate (1), the annular convex groove (16) is a conical groove with a downward opening, and the width of the notch of the conical groove is larger than the width of the groove bottom of the conical groove.

5. The injection molded top cap for a secondary battery according to claim 1, wherein: the pole (3) comprises an end plate (31) and a columnar body (32) arranged on the end plate (31), wherein the end plate (31) is non-circular and is positioned below the stop frame (2); the columnar body (32) sequentially passes through the aligned pole hole (21) and the pole mounting hole (11) upwards to extend to the upper side of the substrate (1), an injection molding gap is reserved between the peripheral wall of the columnar body (32) and the inner hole wall of the pole mounting hole (11), an annular gap for accommodating the sealing element (33) is reserved between the peripheral wall of the columnar body (32) and the inner hole wall of the pole hole (21), the sealing element (33) is sleeved on the columnar body (32), and the sealing element (33) is positioned in the annular gap between the top surface of the end plate (31) and the lower surface of the substrate (1).

6. The injection molded top cap for a secondary battery according to claim 1, wherein: the end plate (31) is provided with a sealing groove (311) encircling the periphery of the columnar body (22), a sealing element (33) is arranged in the sealing groove (311), the sealing element (33) is abutted against the bottom end of the annular convex groove (16), and the inner annular wall of the sealing element (33) is abutted against the outer peripheral wall of the columnar body (22).

7. The injection molded top cap for a secondary battery as claimed in claim 6, wherein: the sealing piece (33) is an annular sealing ring, an annular groove (331) is formed in the upper annular surface of the sealing piece (33), a boss flange (332) is arranged in the lower annular surface of the sealing piece (33), and the boss flange (332) is embedded into the sealing groove (311).

8. The injection molded top cap for a secondary battery according to claim 1, wherein: the columnar body (32) and the upper plastic part (4) are fixed in a concave-convex matching mode.

9. A secondary battery comprising a case (6), the case (6) being provided with an opening, characterized in that: the opening is mounted with the secondary battery injection molded top cover according to any one of claims 1 to 8.

10. A method of manufacturing the secondary battery according to claim 9, comprising the steps of:

step 1, assembling an explosion-proof valve (5) into an explosion-proof valve mounting hole (13) of a substrate (1), and ensuring the sealing between the explosion-proof valve (5) and the explosion-proof valve mounting hole (13);

step 2, assembling a sealing element (33) on the pole (3), embedding a boss flange (332) of the sealing element (33) into a sealing groove (311) of the pole (3), tightly fixing the sealing element (33) at the sealing groove (311) of the end plate (31), preventing displacement during compression, and inclining the pole (3);

step 3, placing the pole (3) assembled with the sealing piece (33), the stop frame (2) and the base plate (1) assembled with the explosion-proof valve (5) into an injection mold from bottom to top in sequence, keeping the pole mounting hole (11) aligned with the pole hole (21), enabling the columnar body (32) of the pole (3) to sequentially pass through the aligned pole hole (21) and the pole mounting hole (11) upwards to extend above the base plate (1), enabling the top surface of the end plate (31) to abut against the second surface of the stop frame (2), and enabling the annular convex groove (16) at the bottom of the base plate (1) to abut against the bottom surface of the annular groove (331);

step 4, after assembly, the whole body is subjected to injection molding through a mold to form a corresponding upper plastic part (4), and when the upper plastic part (4) is subjected to injection molding, the plastic is filled in an outer injection molding area formed by the mold and the convex ring structure, an inner injection molding area defined by the convex ring structure and the polar post, an injection molding gap defined by a polar post mounting hole and the polar post, a substrate through groove and an annular convex groove which are arranged on the substrate, so that an integral secondary battery injection molding top cover among the upper plastic part, the polar post, the substrate and the stop frame is realized;

and 5, sealing and assembling the injection-molded top cover of the secondary battery on the shell of the secondary battery, injecting electrolyte, and installing a sealing plug at the injection hole after the injection is completed to finish packaging.