A battery top cover assembly structure and assembly method

Abstract

The present invention belongs to the technical field of battery production and manufacturing, and specifically relates to a battery top cover assembly structure, including a negative electrode column, a positive electrode column and a top cover sheet, the top cover sheet is provided with a first through hole and a second through hole, the negative electrode column is assembled in the first through hole, the positive electrode column is assembled in the second through hole, the side of the negative electrode column is coated with a first insulating plastic, the space between the positive electrode column and the second through hole is coated with a conductive plastic, and the outer surface of the conductive plastic is coated with a second insulating plastic for preventing the conductive plastic from generating stress due to secondary crystallization. The present invention can solve the problem of stress generated by secondary crystallization of conductive plastic, causing plastic warping and cracking, and is conducive to improving the sealing performance of the electrode column, thereby improving the safety of the battery cell. In addition, the present invention also discloses a battery top cover assembly method.

Description

Technical Field

[0001] The invention belongs to the technical field of battery production and manufacturing, and specifically relates to a battery top cover assembly structure and an assembly method. Background Art

[0002] Nowadays, with the development of modern society and the enhancement of people's environmental awareness, more and more devices choose lithium batteries as power sources, such as mobile phones, laptops, power tools and electric vehicles, etc., which provides a broad space for the application and development of lithium batteries. Among them, lithium batteries used in power tools and electric vehicles are generally called power batteries. Lithium batteries mainly include a shell and an electrolyte built into the shell, and a positive electrode, a battery separator and a negative electrode sheet assembled by stacking or winding assembly, and output electricity to the outside through the top cover pole. The pole and the top cover need to be insulated and tightly combined to prevent electrolyte leakage.

[0003] The inventors have found that the prior art has at least the following problems: the positive electrode is electrically connected to the top cover sheet through conductive plastic, but the conductive plastic will produce secondary crystallization and stress during the encapsulation process, causing the plastic to warp and crack, thereby affecting the sealing performance of the electrode, reducing the safety of the battery cell, and even causing it to be scrapped. Summary of the invention

[0004] One of the purposes of the present invention is to provide a battery top cover assembly structure to address the deficiencies of the prior art, which can solve the problem of stress generated by secondary crystallization of conductive plastic, causing plastic warping and cracking, and is beneficial to improving the sealing performance of the pole, thereby improving the safety of the battery cell.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A battery top cover assembly structure comprises a negative electrode column, a positive electrode column and a top cover sheet, wherein the top cover sheet is provided with a first through hole and a second through hole, the negative electrode column is assembled in the first through hole, the positive electrode column is assembled in the second through hole, the side of the negative electrode column is coated with a first insulating plastic, the area between the positive electrode column and the second through hole is coated with a conductive plastic, and the outer surface of the conductive plastic is coated with a second insulating plastic for preventing the conductive plastic from generating stress due to secondary crystallization.

[0007] As an improvement of the battery top cover assembly structure described in the present invention, the top surface of the conductive plastic is provided with a plurality of concave holes, and the second insulating plastic is provided with protrusions that match the concave holes.

[0008] As an improvement of the battery top cover assembly structure described in the present invention, the first insulating plastic and the second insulating plastic are both one-piece molded structures of PP material, PPS material, TPU material or TPE material, and the conductive plastic is an one-piece molded structure of PPS material, PSU material, PA material or nano material.

[0009] As an improvement of the battery top cover assembly structure described in the present invention, a groove is formed at the top of the first through hole and / or the second through hole, and the groove is used to embed the first insulating plastic or the conductive plastic.

[0010] As an improvement of the battery top cover assembly structure described in the present invention, a plurality of blind holes are arranged along the groove edge of the groove, and the plurality of blind holes are arranged around the groove.

[0011] As an improvement of a battery top cover assembly structure described in the present invention, the negative electrode column includes a first bottom plate and a first column arranged on the first bottom plate, the positive electrode column includes a second bottom plate and a second column arranged on the second bottom plate, the tops of the first column and the second column are both provided with a first step, the bottoms of the first column and the second column are both provided with a second step, a recess is formed between the first step and the second step, and the inner wall of the first insulating plastic and the inner wall of the conductive plastic are both provided with a convex portion that cooperates with the recess.

[0012] As an improvement of the battery top cover assembly structure described in the present invention, the first bottom plate and the first column are formed into a composite pole by friction welding or welding, and the second bottom plate and the second column are an integrally formed structure.

[0013] As an improvement of the battery top cover assembly structure described in the present invention, the negative electrode column and the positive electrode column are both sleeved with sealing rings, and an integrally formed lower plastic is installed at the bottom of the top cover sheet.

[0014] As an improvement of the battery top cover assembly structure described in the present invention, the top cover sheet is also provided with at least one of an explosion-proof valve vent hole and a liquid injection hole, and the lower plastic is correspondingly provided with at least one of an explosion-proof valve receiving hole and a liquid injection through hole, an explosion-proof valve is installed between the explosion-proof valve vent hole and the explosion-proof valve receiving hole, and a protective film is installed on the top of the explosion-proof valve vent hole.

[0015] A second object of the present invention is to provide a battery top cover assembly method, comprising:

[0016] The negative electrode column is inserted into the first through hole and fixed to the top cover sheet, and the positive electrode column is inserted into the second through hole and fixed to the top cover sheet;

[0017] Applying a first insulating plastic to the side of the negative electrode column by injection molding, so that the negative electrode column and the top cover sheet are insulated and connected;

[0018] Conductive plastic is encapsulated between the positive electrode column and the second through hole by injection molding, so that the positive electrode column and the top cover sheet are electrically connected, and then the second insulating plastic is encapsulated on the outer surface of the conductive plastic by injection molding, so that the conductive plastic as a whole is maintained within a preset temperature range to prevent the conductive plastic from generating stress due to secondary crystallization.

[0019] It should be noted that in the assembly method of the present invention, a first through hole and a second through hole are provided on the top cover sheet to facilitate the installation of the negative electrode column and the positive electrode column. The side of the negative electrode column is coated with an integrated first insulating plastic by one-time injection molding, so that the side of the negative electrode column is insulated from the top cover sheet, which can reduce the current in the circuit when a short circuit occurs in the battery. The first injection molding is performed between the positive electrode column and the top cover sheet, that is, the conductive plastic is injected. In order to prevent the conductive plastic from cooling down earlier than the inner layer due to the surface layer cooling down, the inner layer may still be a hot melt, and the inner layer will limit the shrinkage of the surface layer, resulting in the inner layer being in a compressive stress state, while the surface layer is in a tensile stress state. After molding, the conductive plastic is subjected to secondary crystallization and stress is generated. When the surface of the conductive plastic is cooled down, the conductive plastic is cooled down. Before the battery is turned to the other group of injection nozzles through the mold turntable, the second injection is completed by sliding and rotating alternately accordingly, that is, the second insulating plastic is injected. The temperature of the second insulating plastic during the molding process is equivalent to high-temperature annealing of the conductive plastic, which reduces the probability of secondary crystallization of the conductive plastic, eliminates the stress hidden danger of the conductive plastic, ensures that the conductive plastic does not warp, and is beneficial to improving the sealing performance between the top cover sheet and the pole, and improving the safety performance of the battery cell. At the same time, under the premise of ensuring that the top cover sheet is electrically connected to the positive pole through the conductive plastic, the second insulating plastic can not only prevent the conductive plastic from contacting with external parts to generate a large current, but also improve the tightness of the combination with the conductive plastic, which is beneficial to improving the sealing performance between the top cover and the pole.

[0020] The beneficial effects of the present invention are that the present invention includes a negative electrode column, a positive electrode column and a top cover sheet, the top cover sheet is provided with a first through hole and a second through hole, the negative electrode column is assembled in the first through hole, the positive electrode column is assembled in the second through hole, the side of the negative electrode column is coated with a first insulating plastic, the positive electrode column and the second through hole are coated with a conductive plastic, and the outer surface of the conductive plastic is coated with a second insulating plastic for preventing the conductive plastic from generating stress due to secondary crystallization. During the encapsulation process, the surface layer of the conductive plastic cools down earlier than the inner layer, and the inner layer may still be a hot melt. The inner layer will limit the shrinkage of the surface layer, causing the inner layer to be in a compressive stress state, while the surface layer is in a tensile stress state, which will produce secondary crystallization and stress, causing the plastic to warp and crack, thereby affecting the sealing performance of the pole, reducing the safety of the battery cell, and even scrapping it. Therefore, the outer surface of the conductive plastic is encapsulated to form a second insulating plastic to prevent the conductive plastic from secondary crystallization and generating stress after molding. The second insulating plastic is injection molded on the surface of the conductive plastic. The temperature of the second insulating plastic during the molding process is equivalent to high-temperature annealing of the conductive plastic, which reduces the probability of secondary crystallization of the conductive plastic, eliminates the stress hidden dangers of the conductive plastic, ensures that the conductive plastic does not warp, and is conducive to improving the top cover The sealing performance between the sheet and the pole is improved, and the safety performance of the battery cell is improved. At the same time, under the premise of ensuring that the top cover sheet is electrically connected to the positive pole through the conductive plastic, the second insulating plastic can not only prevent the conductive plastic from contacting with external parts to generate a large current, but also improve the tightness of the combination with the conductive plastic, which is beneficial to improving the sealing performance between the top cover and the pole; the conductivity of the conductive plastic is obtained by mixing conductive substances such as carbon black, metal powder, etc. in it, which plays a role in providing carriers in the conductive plastic. The hardness of the conductive plastic is greater than the external second insulating plastic, which improves the tightness of the combination between the conductive plastic and the second insulating plastic; the side of the negative pole is covered with the first insulating plastic, so that the side of the negative pole is insulated from the top cover sheet, which can reduce the current in the loop when the battery is short-circuited. The present invention can solve the problem of stress generated by secondary crystallization of the conductive plastic, causing plastic warping and cracking, which is beneficial to improving the sealing performance of the pole, thereby improving the safety of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the present invention.

[0022] Figure 2 It is a schematic diagram of the decomposition structure of the present invention.

[0023] Figure 3 It is a cross-sectional schematic diagram of the negative electrode column assembly and the top cover sheet in the present invention.

[0024] Figure 4 It is a cross-sectional schematic diagram of the positive electrode column assembly and the top cover sheet of the present invention.

[0025] Among them: 1-negative pole; 2-positive pole; 3-top cover; 11-first bottom plate; 12-first column; 21-second bottom plate; 22-second column; 31-first through hole; 32-second through hole; 33-groove; 331-blind hole; 4-first insulating plastic; 5-conductive plastic; 51-recessed hole; 6-second insulating plastic; 61-protrusion; 7-first step; 8-second step; 9-sealing ring; 10-lower plastic; 20-explosion-proof valve; 30-protective film. DETAILED DESCRIPTION

[0026] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of components as the criteria for distinction. For example, "including" mentioned throughout the specification and claims is an open term, so it should be interpreted as "including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve technical problems within a certain error range and basically achieve technical effects.

[0027] In the description of the present invention, it should be understood that the directions or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", "horizontal", etc. are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention.

[0028] In the invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0029] The present invention will be further described in detail below in conjunction with the accompanying drawings, but this is not intended to limit the present invention.

[0030] Example 1

[0031] like Figures 1 to 4As shown, a battery top cover assembly structure includes a negative electrode column 1, a positive electrode column 2 and a top cover sheet 3, the top cover sheet 3 is provided with a first through hole 31 and a second through hole 32, the negative electrode column 1 is assembled in the first through hole 31, the positive electrode column 2 is assembled in the second through hole 32, the side of the negative electrode column 1 is covered with a first insulating plastic 4, the positive electrode column 2 and the second through hole 32 are covered with a conductive plastic 5, and the outer surface of the conductive plastic 5 is covered with a second insulating plastic 6 for preventing the conductive plastic 5 from generating stress due to secondary crystallization. During the encapsulation process of the conductive plastic 5, the surface layer cools down earlier than the inner layer, and the inner layer may still be a hot melt. The inner layer will limit the shrinkage of the surface layer, causing the inner layer to be in a compressive stress state, while the surface layer is in a tensile stress state, which will produce secondary crystallization and stress, causing the plastic to warp and crack, thereby affecting the sealing performance of the pole, reducing the safety of the battery cell, and even scrapping. Therefore, the outer surface of the conductive plastic 5 is encapsulated to form a second insulating plastic 6 to prevent the conductive plastic 5 from being crystallized and generating stress after the conductive plastic 5 is formed. The second insulating plastic 6 is injection molded on the surface of the conductive plastic 5, and the temperature during the molding process of the second insulating plastic 6 is equivalent to high-temperature annealing of the conductive plastic 5, which reduces the probability of secondary crystallization of the conductive plastic 5, eliminates the stress hidden danger of the conductive plastic 5, ensures that the conductive plastic 5 does not warp, and is conducive to improving the top cover sheet 3 and the sealing performance between the poles, thereby improving the safety performance of the battery cell. At the same time, under the premise of ensuring that the top cover sheet 3 is electrically connected to the positive pole 2 through the conductive plastic 5, the second insulating plastic 6 can not only prevent the conductive plastic 5 from contacting with external parts to generate a large current, but also improve the tightness of the combination with the conductive plastic 5, which is beneficial to improving the sealing performance between the top cover and the pole; the conductivity of the conductive plastic 5 is obtained by mixing conductive substances such as carbon black, metal powder, etc. in it, which plays a role in providing carriers in the conductive plastic 5. The hardness of the conductive plastic 5 is greater than that of the external second insulating plastic 6, which improves the tightness of the combination between the conductive plastic 5 and the second insulating plastic 6; the side of the negative pole 1 is encapsulated with the first insulating plastic 4, so that the side of the negative pole 1 is insulated from the top cover sheet 3, which can reduce the current in the circuit when a short circuit occurs in the battery.

[0032] Preferably, the top surface of the conductive plastic 5 is provided with a plurality of concave holes 51, and the second insulating plastic 6 is provided with protrusions 61 that match the concave holes 51. The plurality of concave holes 51 and the protrusions 61 form a concave-convex matching structure, which reduces the probability of the conductive plastic 5 becoming loose during use, and at the same time, improves the bite force of the contact surface between the conductive plastic 5 and the second insulating plastic 6, which is conducive to preventing the conductive plastic 5 from warping.

[0033] Preferably, the first insulating plastic 4 and the second insulating plastic 6 are both integrally formed structures of PP material, PPS material, TPU material or TPE material, and the conductive plastic 5 is an integrally formed structure of PPS material, PSU material, PA material or nano material. PP material, PPS material, TPU material or TPE material are all resistant to high temperature and corrosion, and have excellent mechanical properties and insulation properties, which are helpful to improve the service life of the insulating plastic 4, thereby improving the quality of the battery, and have good environmental protection performance and fire prevention effect, which is more in line with the environmental protection requirements in the field of new energy vehicles. According to the structure and cost requirements of the battery, PP material, PPS material, TPU material or TPE material can be used to form the first insulating plastic 4 and the second insulating plastic 6. The second insulating plastic 6 is embedded in the concave hole 51 by overmolding, which reduces the probability of the conductive plastic 5 loosening during use. At the same time, the bite force of the contact surface between the conductive plastic 5 and the second insulating plastic 6 is improved, which is helpful to prevent the conductive plastic 5 from warping. The conductive plastic 5 is obtained by mixing conductive substances such as carbon black, metal powder, etc. in PPS material, PSU material, PA material or nano material, and plays the role of providing carriers in the conductive plastic 5.

[0034] Preferably, a groove 33 is formed at the top of the first through hole 31 and / or the second through hole 32, and the groove 33 is used to embed the first insulating plastic 4 or the conductive plastic 5. The design of the groove 33 ensures the stability between the top cover sheet 3 and each pole, eliminates the riveting process, helps to reduce production costs and improve production efficiency. In addition, this design not only ensures that the function of the battery is not affected, but also reduces the space occupied by the top cover inside the battery, so that larger batteries can be placed inside the battery, thereby improving the energy density of the battery.

[0035] Preferably, a plurality of blind holes 331 are provided along the groove edge of the groove 33, and the plurality of blind holes 331 are provided around the groove 33. Adding a plurality of blind holes 331 increases the bite force between the groove 33 and the plastic surface, prevents the first insulating plastic 4 or the conductive plastic 5 from warping, and helps to improve the stability between the top cover sheet 3 and the first insulating plastic 4 or the conductive plastic 5, thereby improving the safety of the battery.

[0036] Preferably, the negative electrode column 1 includes a first bottom plate 11 and a first column 12 arranged on the first bottom plate 11, the positive electrode column 2 includes a second bottom plate 21 and a second column 22 arranged on the second bottom plate 21, the tops of the first column 12 and the second column 22 are both provided with a first step 7, the bottoms of the first column 12 and the second column 22 are both provided with a second step 8, a recess is formed between the first step 7 and the second step 8, and the inner walls of the first insulating plastic 4 and the conductive plastic 5 are both provided with a convex portion that cooperates with the recess. A recess is formed between the first step 7 and the second step 8, which is used to tighten the tension in the upper and lower directions of the plastic. At the same time, the inner wall of the first insulating plastic 4 and the inner wall of the conductive plastic 5 are embedded in the recess to tighten the pole, thereby realizing the insulation function of the top cover and the pole. Among them, the second step 8 can increase the contact area between the bottom plate and the column, thereby improving the stability between the two. Among them, the first step 7 is directly formed by a stamping process. Compared with the recess formed by a machine processing process, it not only improves the current carrying capacity of the pole, but also avoids the generation of metal wires during the processing process, thereby improving the safety of the battery.

[0037] Preferably, the first bottom plate 11 and the first column 12 are friction welded or fused to form a composite pole, and the second bottom plate 21 and the second column 22 are an integrally formed structure. The first column 12 can be made of metal aluminum, and the first bottom plate 11 is a metal material corresponding to the negative electrode sheet. The use of a composite pole can ensure that the quality of the battery is not affected and reduce the production cost of the negative electrode column 1; the positive electrode column 2 is the positive electrode, and the second bottom plate 21 and the second column 22 can both be made of metal aluminum. The use of an integrally formed structure can ensure that the quality of the battery is not affected and reduce the production cost of the positive electrode column 2.

[0038] Preferably, the negative pole 1 and the positive pole 2 are both sleeved with a sealing ring 9, and the bottom of the top cover sheet 3 is installed with an integrally formed lower plastic 10. The sealing ring 9 is fluororubber, which can seal the gap between the pole and the pole through hole, prevent the electrolyte from corroding the first insulating plastic 4 wall and the conductive plastic 5 through the gap, and also play the role of insulating the pole and the pole through hole; the lower plastic 10 can improve the insulation performance of the top cover sheet 3, and can also prevent the electrolyte from corroding the top cover sheet 3 and causing a short circuit in the battery.

[0039] Preferably, the top cover sheet 3 is also provided with at least one of an explosion-proof valve vent hole and a liquid injection hole, and the lower plastic 10 is correspondingly provided with at least one of an explosion-proof valve receiving hole and a liquid injection through hole, an explosion-proof valve 20 is installed between the explosion-proof valve vent hole and the explosion-proof valve receiving hole, and a protective film 30 is installed on the top of the explosion-proof valve vent hole. The liquid injection hole facilitates the injection of electrolyte into the battery, and the explosion-proof valve 20 can automatically and quickly release the pressure of the battery when the internal pressure of the battery rises due to overcharging, over-discharging, overcurrent and internal short circuit of the battery, so as to avoid the occurrence of safety accidents caused by battery explosion, wherein the explosion-proof valve vent hole cooperates with the explosion-proof valve receiving hole to ensure that the function of the explosion-proof valve 20 can be realized, and the liquid injection hole cooperates with the liquid injection through hole to ensure that the function of the liquid injection hole can be realized, and the protective film 30 is a PET film, which plays a role in protecting the explosion-proof valve 20 and preventing dust or impurities from entering the explosion-proof valve 20.

[0040] The working principle of the present invention is:

[0041] During the encapsulation process, the surface layer of the conductive plastic cools down earlier than the inner layer, and the inner layer may still be a hot melt. The inner layer will limit the shrinkage of the surface layer, causing the inner layer to be in a compressive stress state, while the surface layer is in a tensile stress state, which will produce secondary crystallization and stress, causing the plastic to warp and crack, thereby affecting the sealing performance of the pole, reducing the safety of the battery cell, and even scrapping it. Therefore, the outer surface of the conductive plastic 5 is encapsulated to form a second insulating plastic 6 to prevent the conductive plastic 5 from secondary crystallization and generating stress after the conductive plastic 5 is formed. The second insulating plastic 6 is injection molded on the surface of the conductive plastic 5, and the temperature during the molding process of the second insulating plastic 6 is equivalent to high-temperature annealing of the conductive plastic 5, thereby reducing the probability of secondary crystallization of the conductive plastic 5, eliminating the stress hidden danger of the conductive plastic 5, and ensuring that the conductive plastic 5 does not warp, which is beneficial to improving the top cover sheet 3 and The sealing performance between the poles improves the safety performance of the battery cell. At the same time, under the premise of ensuring that the top cover sheet 3 is electrically connected to the positive pole 2 through the conductive plastic 5, the second insulating plastic 6 can not only prevent the conductive plastic 5 from contacting with external parts to generate a large current, but also improve the tightness of the combination with the conductive plastic 5, which is beneficial to improving the sealing performance between the top cover and the pole; the conductivity of the conductive plastic 5 is obtained by mixing conductive substances such as carbon black, metal powder, etc. in it, which plays a role in providing carriers in the conductive plastic 5. The hardness of the conductive plastic 5 is greater than that of the external second insulating plastic 6, which improves the tightness of the combination between the conductive plastic 5 and the second insulating plastic 6; the side of the negative pole 1 is encapsulated with the first insulating plastic 4, so that the side of the negative pole 1 is insulated from the top cover sheet 3, which can reduce the current in the circuit when a short circuit occurs in the battery.

[0042] Example 2

[0043] like Figures 1 to 4 As shown, a battery top cover assembly method includes:

[0044] The negative electrode column 1 is passed through the first through hole 31 and fixed to the top cover sheet 3, and the positive electrode column 2 is passed through the second through hole 32 and fixed to the top cover sheet 3;

[0045] The first insulating plastic 4 is encapsulated on the side of the negative electrode column 1 by injection molding, so that the negative electrode column 1 and the top cover sheet 3 are insulated and connected;

[0046] The conductive plastic 5 is encapsulated between the positive electrode column 2 and the second through hole 32 by injection molding, so that the positive electrode column 2 and the top cover sheet 3 are electrically connected, and then the second insulating plastic 6 is encapsulated on the outer surface of the conductive plastic 5 by injection molding, so that the conductive plastic 5 as a whole is kept within a preset temperature range to prevent the conductive plastic 5 from generating stress due to secondary crystallization.

[0047] It should be noted that in the assembly method of the present invention, a first through hole 31 and a second through hole 32 are provided on the top cover sheet 3 to facilitate the installation of the negative electrode column 1 and the positive electrode column 2. The side of the negative electrode column 1 is coated with an integrated first insulating plastic 4 by one-time injection molding, so that the side of the negative electrode column 1 is insulated from the top cover sheet 3, and the current in the circuit can be reduced when a short circuit occurs in the battery; the first injection molding is performed between the positive electrode column 2 and the top cover sheet 3, that is, the conductive plastic 5 is injected. In order to prevent the conductive plastic 5 from cooling down earlier than the inner layer due to the surface layer cooling down, the inner layer may still be a hot melt, and the inner layer will limit the shrinkage of the surface layer, resulting in the inner layer being in a compressive stress state, while the surface layer is in a tensile stress state. After molding, the conductive plastic 5 is secondary crystallized and stress is generated. Before the surface of the conductive plastic 5 cools down, it is transferred to another set of injection nozzles through the mold turntable and slides accordingly. and rotate alternately to complete the second injection molding, that is, inject the second insulating plastic 6. The temperature during the molding process of the second insulating plastic 6 is equivalent to high-temperature annealing of the conductive plastic 5, which reduces the probability of secondary crystallization of the conductive plastic 5, eliminates the stress hidden danger of the conductive plastic 5, and ensures that the conductive plastic 5 does not warp, which is beneficial to improving the sealing performance between the top cover sheet 3 and the pole, and improving the safety performance of the battery core. At the same time, under the premise of ensuring that the top cover sheet 3 is electrically connected to the positive pole 2 through the conductive plastic 5, the second insulating plastic 6 can not only prevent the conductive plastic 5 from contacting with external parts to generate a large current, but also improve the tightness of the combination with the conductive plastic 5, which is beneficial to improving the sealing performance between the top cover and the pole. In this embodiment, the preset temperature range is 160°C to 220°C, but the present invention is not limited thereto. The conductive plastic 5 can be injected twice without crystallization.

[0048] According to the disclosure and teaching of the above description, those skilled in the art to which the present invention belongs can also change and modify the above embodiment. Therefore, the present invention is not limited to the above specific embodiment, and any obvious improvement, replacement or modification made by those skilled in the art on the basis of the present invention belongs to the protection scope of the present invention. In addition, although some specific terms are used in this specification, these terms are only for the convenience of description and do not constitute any limitation to the present invention.

Claims

1. A battery top cover assembly structure, comprising a negative electrode column (1), a positive electrode column (2) and a top cover sheet (3), wherein the top cover sheet (3) is provided with a first through hole (31) and a second through hole (32), wherein the negative electrode column (1) is assembled in the first through hole (31), and the positive electrode column (2) is assembled in the second through hole (32), characterized in that: The side of the negative electrode column (1) is encapsulated with a first insulating plastic (4), the positive electrode column (2) and the second through hole (32) are encapsulated with a conductive plastic (5), and before the outer surface of the conductive plastic (5) is cooled, a second insulating plastic (6) is formed by injection molding on the outer surface of the conductive plastic (5) to prevent the conductive plastic (5) from generating stress due to secondary crystallization; The top surface of the conductive plastic (5) is provided with a plurality of recessed holes (51), the second insulating plastic (6) is provided with protrusions (61) that cooperate with the recessed holes (51), the second insulating plastic (6) is an integrally molded structure of PP material, PPS material, TPU material or TPE material, and the conductive plastic (5) is an integrally molded structure of PPS material, PSU material, PA material or nano material.

2. A battery top cover assembly structure as claimed in claim 1, characterized in that: The first insulating plastic (4) is an integrally formed structure of PP material, PPS material, TPU material or TPE material.

3. A battery top cover assembly structure as claimed in claim 1, characterized in that: A groove (33) is formed at the top of the first through hole (31) and / or the second through hole (32), and the groove (33) is used to embed the first insulating plastic (4) or the conductive plastic (5).

4. A battery top cover assembly structure as claimed in claim 3, characterized in that: A plurality of blind holes (331) are arranged along the groove edge of the groove (33), and the plurality of blind holes (331) are arranged around the groove (33).

5. A battery top cover assembly structure as claimed in claim 1, characterized in that: The negative electrode column (1) comprises a first bottom plate (11) and a first column (12) arranged on the first bottom plate (11); the positive electrode column (2) comprises a second bottom plate (21) and a second column (22) arranged on the second bottom plate (21); the tops of the first column (12) and the second column (22) are both provided with a first step (7); the bottoms of the first column (12) and the second column (22) are both provided with a second step (8); a recess is formed between the first step (7) and the second step (8); and the inner walls of the first insulating plastic (4) and the inner walls of the conductive plastic (5) are both provided with a protrusion that matches the recess.

6. A battery top cover assembly structure as claimed in claim 5, characterized in that: The first bottom plate (11) and the first column (12) are friction welded or fused to form a composite pole, and the second bottom plate (21) and the second column (22) are an integrally formed structure.

7. A battery top cover assembly structure as claimed in claim 1, characterized in that: The negative electrode column (1) and the positive electrode column (2) are both sleeved with sealing rings (9), and the bottom of the top cover sheet (3) is installed with an integrally formed lower plastic (10).

8. A battery top cover assembly structure as claimed in claim 7, characterized in that: The top cover sheet (3) is also provided with at least one of an explosion-proof valve vent hole and a liquid injection hole, and the lower plastic (10) is correspondingly provided with at least one of an explosion-proof valve receiving hole and a liquid injection through hole, an explosion-proof valve (20) is installed between the explosion-proof valve vent hole and the explosion-proof valve receiving hole, and a protective film (30) is installed on the top of the explosion-proof valve vent hole, and the protective film (30) is a PET film.

9. A battery top cover assembly method, used for preparing the battery top cover assembly structure according to any one of claims 1 to 8, characterized in that: include: The negative electrode column (1) is inserted into the first through hole (31) and fixed to the top cover sheet (3); the positive electrode column (2) is inserted into the second through hole (32) and fixed to the top cover sheet (3); The first insulating plastic (4) is encapsulated on the side of the negative electrode column (1) by injection molding, so that the negative electrode column (1) and the top cover sheet (3) are insulated and connected; The conductive plastic (5) is encapsulated between the positive electrode column (2) and the second through hole (32) by injection molding, so that the positive electrode column (2) and the top cover sheet (3) are electrically connected, and then before the outer surface of the conductive plastic (5) is cooled, the second insulating plastic (6) is injection molded onto the outer surface of the conductive plastic (5), so that the conductive plastic (5) as a whole is maintained within a preset temperature range, thereby preventing the conductive plastic (5) from generating stress due to secondary crystallization.

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