Top cover assembly manufacturing method, top cover assembly and battery cell

Abstract

The invention relates to a novel top cover assembly manufacturing method and a related product thereof. The requirements of modern batteries for high integration level, high reliability and low cost are met. The manufacturing process is simplified and the manufacturing cost is reduced by adopting the injection molding integrated technology, the explosion-proof structure is formed on the top cover plate in a nicking mode, and the safety and the reliability of the product are improved. In the manufacturing process, firstly, the pole terminal is connected with the top cover plate, the welding piece is welded to the inner welding face of the pole terminal, a current transmission path is optimized, the connection firmness is enhanced, an injection molding space is constructed among the pole terminal, the top cover plate and the welding piece, a thermoplastic material is injected to form an injection molding sealing piece, and all the assemblies are tightly connected. The first through hole and the second through hole are designed in the welding piece and are aligned with the liquid injection hole in the top cover plate, so that liquid can be efficiently and safely injected into the battery cell. And meanwhile, the injection molding efficiency and the product quality are guaranteed by optimizing the flowing path of the injection molding material.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a method for manufacturing a top cover assembly, a top cover assembly and a battery cell. Background Art

[0002] With the continuous development of modern battery technology, the top cover assembly is an important part of the battery system, and its manufacturing process and performance directly affect the overall quality and safety of the battery. However, the design and manufacturing of the current traditional top cover structure face many challenges.

[0003] First, the top cover structure is relatively complex, the manufacturing process is cumbersome and the integration is not high, which not only increases the production cost, but also limits the improvement of production efficiency, especially in the manufacturing process of battery cover and explosion-proof valve. Since these parts are extremely thin stamping parts, lubricating oil and cleaning fluid are often easily left after processing. These residual liquids will quickly vaporize and float to the surface of the molten pool during high-power density laser welding, causing cracks and splashes on the weld surface, forming pits and holes, which seriously affect the quality and reliability of the weld. Secondly, in traditional battery cells, various loose parts in the cover are usually mechanically connected by rivet structures. However, the riveting process often damages the surface of the workpiece, affecting the appearance and surface quality of the product. In order to overcome this defect, there are many problems that need to be solved. How to simplify the manufacturing process, improve the integration, reduce the impact of residual liquid on welding, and optimize the process while ensuring product performance and quality are important directions for research and development of top cover components and battery cell manufacturing technology. Summary of the invention

[0004] The purpose of this application is to provide a method for manufacturing a top cover assembly, which can reduce the number of cover parts and use injection molding technology to replace the rivet structure to reduce the impact on the workpiece surface. In addition, notches are used instead of explosion-proof valves to reduce the impact of explosion-proof valves on products. The purpose of this application is achieved through the following technical solutions. The method for manufacturing a top cover assembly of this application includes: Connect the pole terminal to the top cover plate; Welding a welding piece to the inner welding surface of the pole terminal to form an injection molding space between the pole terminal, the top cover plate and the welding piece; Injection molding is performed in the injection molding space to form an injection molding seal that tightly connects the top cover plate, the pole terminal and the welding piece; Wherein, the top cover plate includes an explosion-proof structure formed by scoring.

[0005] In one of the embodiments, a first through hole is formed in the welding sheet at a position corresponding to the explosion-proof structure, and an isolation piece corresponding to the explosion-proof structure is also formed before injection molding, and the isolation piece is used to prevent the injection material from flowing to the explosion-proof structure during the injection molding process.

[0006] In one of the embodiments, the method further includes forming an injection molding channel in the terminal, and performing injection molding through the injection molding channel during the injection molding process.

[0007] In one of the embodiments, the step of forming a liquid injection hole in the top cover plate is also included.

[0008] In one of the embodiments, a second through hole is further formed in the welding sheet, and when the welding sheet is welded to the pole terminal, the injection hole is aligned with the second through hole.

[0009] In one embodiment, the second through hole is an arc-shaped through hole.

[0010] In one of the embodiments, the method further includes welding a busbar to weld the busbar to the welding piece.

[0011] In addition, the present application also provides a top cover assembly, which is obtained by the above-mentioned top cover assembly manufacturing method, comprising: Pole terminals, top cover plates, injection molded seals, welding pieces; The injection-molded seal is formed in the space formed by the top cover plate, the welding piece and the pole terminal by injection molding, so as to tightly connect the top cover plate, the pole terminal and the welding piece.

[0012] In one embodiment, more than two pole terminals are included, and each pole terminal has a corresponding injection-molded seal formed by injection molding.

[0013] The present application further provides a battery cell, comprising the aforementioned top cover assembly.

[0014] Compared with the prior art, this application has the following beneficial effects: Compared with the prior art, the top cover assembly manufacturing method, top cover assembly and battery cell provided in this application can simplify the manufacturing process and reduce the number of cover plate parts. This application tightly connects the pole terminal, welding plate and top cover plate through injection molding seals, simplifies the manufacturing process and reduces the use of cover plate parts. This technical feature not only improves production efficiency and reduces manufacturing costs, but also helps to improve the overall performance and reliability of the product. The use of injection molding technology instead of traditional rivet structure effectively avoids damage to the workpiece surface during riveting, thereby maintaining the integrity and surface quality of the product appearance, making the top cover assembly more beautiful, and at the same time improving the market competitiveness of the product.

[0015] An explosion-proof structure is formed on the top cover plate by scoring, replacing the traditional explosion-proof valve. This design not only simplifies the structure of the top cover assembly, but also reduces the impact of the explosion-proof valve on the overall performance and manufacturing process of the product. The scored explosion-proof structure can more effectively relieve pressure on the battery cell to ensure the safe operation of the battery cell. A first through hole is formed in the welding sheet at the position corresponding to the explosion-proof structure, and an isolation piece is formed before injection molding to prevent the injection molding material from flowing to the explosion-proof structure during the injection molding process. In addition, by forming an injection molding channel in the terminal to ensure the smooth progress of the injection molding process, these technical features further improve the manufacturing accuracy and product quality of the top cover assembly.

[0016] An injection hole is formed in the top cover plate, and an arc-shaped through hole is formed in the welding sheet, so that when the welding sheet is welded to the pole terminal, the injection hole and the second through hole can be accurately aligned, which not only facilitates the injection operation of the battery cell, but also helps to improve the performance and safety of the battery cell. The present application also provides a top cover assembly design including more than two pole terminals, each pole terminal has a corresponding injection molded seal, which improves the power density and energy output of the battery cell. The present application reduces the use of upper and lower plastic structures through an injection molding integrated connection method, reduces material costs, simplifies the product structure, and improves the reliability and stability of the product.

[0017] The top cover assembly manufacturing method, top cover assembly and battery cell provided in the present application all show beneficial effects in simplifying the manufacturing process, reducing the number of cover plate parts, improving the surface quality of the workpiece, optimizing the explosion-proof structure design, improving the manufacturing accuracy and product quality, facilitating the liquid injection operation, enhancing the current transmission capacity and reducing the material cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic flow chart of a method for manufacturing a top cover assembly in an embodiment of the present application; Figure 2 is a schematic diagram of the exploded structure of the top cover assembly in a specific embodiment of the present application; Figure 3 is a schematic diagram of the exploded structure of the top cover assembly from another angle in a specific embodiment of the present application; Figure 4 It is a schematic diagram of the cross-sectional structure of the top cover assembly in a specific embodiment of the present application.

[0019] Explanation of reference numerals: 100, pole terminal; 200, top cover plate; 210, notch; 220, injection hole; 300, injection molding seal; 400, welding sheet; 410, first through hole; 420, second through hole; 500, busbar. DETAILED DESCRIPTION

[0020] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. It is to be understood that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only some structures related to the present application are shown in the accompanying drawings, rather than all structures. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0021] The terms "including" and "having" and any variations thereof in this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products or devices.

[0022] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0023] With the continuous advancement of battery technology and changes in market demand, traditional top cover assembly manufacturing methods and structures have been unable to meet the requirements of modern battery systems for high integration, high reliability and low cost. Therefore, a new top cover assembly manufacturing method and related products are developed. This application proposes a new top cover assembly manufacturing method, which achieves high integration and high performance of the top cover assembly by simplifying the manufacturing process and optimizing the structural design. Specifically, the method of this application adopts injection molding technology to replace the traditional rivet structure, reducing the use of cover parts and reducing manufacturing costs; an explosion-proof structure is formed by notching 210, replacing the traditional explosion-proof valve, thereby improving the safety and reliability of the product. Please refer to Figures 1 to 4 As shown, a method for manufacturing a top cover assembly in a preferred embodiment of the present application specifically includes: connecting a pole terminal 100 with a top cover plate 200, welding a welding piece 400 to an inner welding surface of the pole terminal 100, forming an injection molding space between the pole terminal 100, the top cover plate 200 and the welding piece 400, and performing injection molding into the injection molding space to form an injection molding seal 300 that tightly connects the top cover plate 200, the pole terminal 100 and the welding piece 400, wherein the top cover plate 200 includes an explosion-proof structure formed by notching 210.

[0024] The manufacturing method of the top cover assembly, its unique and efficient process flow specifically covers the following steps: First, the pole terminal 100 is accurately connected to the top cover plate 200 to ensure the electrical conductivity and structural stability between the two. Next, the welding piece 400 is welded to the inner welding surface of the pole terminal 100 by welding. This step not only enhances the firmness of the connection, but also optimizes the current transmission path and reduces energy loss. The above two steps are not strictly limited in order. It can be that the pole terminal 100 is connected to the top cover plate 200 after the welding piece 400 is welded, or the pole terminal 100 is first connected to the top cover plate 200, and then the welding piece 400 is welded to the pole terminal 100. An injection molding space is constructed between the pole terminal 100, the top cover plate 200 and the welding piece 400. In the injection molding process, the material is injected into the injection molding space. Through temperature control and pressure management, the thermoplastic material quickly fills the entire space and tightly wraps all components to form a strong and sealed injection molding seal 300. This step not only achieves a tight connection between the top cover plate 200, the pole terminal 100 and the welding piece 400, but also greatly improves the waterproof, dustproof and explosion-proof capabilities of the entire top cover assembly.

[0025] The top cover plate 200 forms an explosion-proof structure by means of notches 210. The notches 210 provide a controllable release path for the internal pressure without affecting the overall strength of the top cover plate 200. Once the internal pressure of the battery rises abnormally, the notch 210 area will rupture first, effectively releasing the pressure, thereby preventing the battery from exploding, enhancing the structural stability and electrical performance, and through the injection molding sealing process, a firm connection is formed between the components of the top cover assembly to ensure the stability of electrical conduction and the durability of the structure. The design of the notch 210 explosion-proof structure provides a safe and controllable release mechanism for the internal pressure of the battery, reduces the risk of battery explosion, and improves the overall safety of the product. Compared with the traditional manufacturing process, this method reduces the use of components, simplifies the manufacturing process through the injection molding integrated molding technology, reduces the production cost, and improves the production efficiency. This application reduces the upper plastic and lower plastic structures, cancels the rivet fixing method of the terminal and the cover plate, and uses injection molding to connect them together, presses out the notch 210 at the cover plate, and uses the notch 210 instead of the explosion-proof valve to relieve the pressure of the battery cell.

[0026] Specifically, a first through hole 410 is formed in the welding sheet 400 at a position corresponding to the explosion-proof structure, and an isolating piece corresponding to the explosion-proof structure is also formed before injection molding, and the isolating piece is used to prevent the injection molding material from flowing to the explosion-proof structure during the injection molding process. In the welding sheet 400, a first through hole 410 is designed and processed corresponding to the precisely preset position of the explosion-proof structure to ensure the alignment and matching between the welding sheet 400 and the explosion-proof structure, and provide the necessary space preparation for the subsequent injection molding process. Before the injection molding process, an isolating piece corresponding to the explosion-proof structure is formed to ensure that it can effectively block the injection molding material from flowing to the explosion-proof structure area during the injection molding process. The use of this isolating piece, based on its precise size, shape and material selection, can construct a shielding structure, thereby preventing the injection molding material from entering the interior of the explosion-proof structure during the injection molding process, and avoiding the risk of explosion-proof performance degradation or failure due to material penetration.

[0027] In a further technical solution, the explosion-proof structure is an annular notch 210 formed on the top cover plate 200 around the pole terminal 100. The first through hole 410 does not need to be completely aligned with the explosion-proof structure. A gap can be formed between the top cover plate 200 and the welding piece 400, and the gap is not filled with injection molding material. In a preferred technical solution, an annular retaining wall (formed by a material that can be removed after injection molding) can be used to form an injection molding space between the pole terminal 100, the top cover plate 200, the welding piece 400 and the retaining wall. The retaining wall is removed after injection molding, and the retaining wall is set in the annular notch 210. In this way, the top cover plate 200 and the welding piece 400 can be left out while the injection molding seal 300 is formed, so that the notch 210 is connected to the inside of the battery cell through the space, so that the air pressure can be transmitted to the notch 210, and the explosion-proof effect is achieved through the notch 210.

[0028] Specifically, it also includes the step of forming an injection channel in the terminal, and performing injection molding through the injection channel during the injection molding process. An injection channel is constructed inside the terminal. During the injection molding stage, this injection channel becomes a channel connecting the injection molding mechanism and the inside of the terminal. The injection molding material is guided to the inside of the terminal through the injection molding channel under precisely controlled temperature and pressure, ensuring that the injection molding material can evenly and fully fill the inside of the terminal, and effectively avoiding structural defects caused by uneven material distribution or insufficient injection molding pressure. The design of the injection molding channel optimizes the flow path of the injection molding material, reduces the resistance during the injection molding process, and can greatly improve the injection molding efficiency. Injection molding through the injection molding channel can ensure the uniform distribution of the injection molding material inside the terminal. The design of the injection molding channel enables each injection molding process to maintain a high degree of consistency, thereby ensuring the stability and reliability of product quality. By forming an injection molding channel inside the terminal and making full use of this channel during the injection molding process, the injection molding efficiency and product quality are improved.

[0029] Specifically, it also includes the step of forming a liquid injection hole 220 in the top cover plate 200. Based on the internal structure design of the product, the liquid flow characteristics and the liquid injection process requirements, the position, size, shape and number of the liquid injection holes 220 are determined to ensure that the liquid injection task can be completed efficiently and safely without affecting the overall structure and performance of the product. During the liquid injection process, the liquid is introduced into the battery cell through the liquid injection hole 220 under appropriate pressure and flow control, and the internal space of the battery cell is filled evenly, quickly and safely.

[0030] Specifically, a second through hole 420 is also formed in the welding sheet 400. When the welding sheet 400 is welded to the pole terminal 100, the injection hole 220 is aligned with the second through hole 420. The second through hole 420 is a circular arc bar through hole. In the manufacturing process, the design of the welding sheet 400 is optimized. The second through hole 420 is formed on the welding sheet 400, and the alignment with the injection hole 220 in the top cover plate 200 is achieved during the welding process. The circular arc bar design not only ensures good matching between the through hole and the injection hole 220, but also improves the smoothness of liquid flow and reduces flow resistance. In the process of welding the welding sheet 400 to the pole terminal 100, positioning and welding technology are used to ensure that the second through hole 420 and the injection hole 220 can be accurately aligned, ensuring that the liquid can smoothly flow from the injection hole 220 and enter the battery cell through the second through hole 420, and can also avoid liquid leakage or poor flow caused by alignment deviation.

[0031] Specifically, the process further includes welding the busbar 500, wherein the busbar 500 is welded to the welding sheet 400. This process involves welding the busbar 500 to the welding sheet 400, and the welding sheet 400 may include a protruding structure for connection. The design of the busbar 500 fully considers the current distribution, heat transfer, and welding reliability, and adopts welding technology and equipment to ensure that the busbar 500 and the welding sheet 400 can be firmly and reliably connected.

[0032] In addition, the present application also provides a top cover assembly, which is obtained by the above-mentioned top cover assembly manufacturing method, including: a pole terminal 100, a top cover plate 200, an injection molded seal 300, and a welding piece 400, wherein the injection molded seal 300 is formed by injection molding in the space formed by the top cover plate 200, the welding piece 400 and the pole terminal 100, and the top cover plate 200, the pole terminal 100 and the welding piece 400 are tightly connected. The injection molded seal 300 plays an important role in this top cover assembly. It fills the space formed by the top cover plate 200, the welding piece 400 and the pole terminal 100, and these components are tightly combined by the injection molding process to form a seamless and strong whole. The material selection and injection molding process of the injection molded seal 300 are designed and optimized to ensure that it can provide excellent sealing performance and mechanical strength. During the injection molding process, the injection molding material is injected into the mold under high pressure, and the shape and size of the formed injection molding seal 300 completely match the space formed by the top cover plate 200, the welding piece 400 and the pole terminal 100. As the injection molding material cools and solidifies, it tightly wraps these components to form a solid sealing structure. It can effectively prevent interference from the external environment, enhance the connection strength between components, and improve the overall stability and reliability of the top cover assembly. In a preferred technical solution, the surface of the pole terminal 100, the top cover plate 200, and the welding piece 400 can be processed, and the surface bonding force between the injection molding material and the above structure is enhanced, so that it is more tightly bonded to the injection molding material, thereby improving the sealing performance, especially the material of the top cover plate 200, which can be used. The material that can be mutually soluble at the interface after injection molding.

[0033] Specifically, more than two pole terminals 100 are included, and each pole terminal 100 has a corresponding injection-molded seal 300 formed by injection molding.

[0034] The present application further provides a battery cell, including the aforementioned top cover assembly, which integrates the technical advantages of the top cover assembly into the battery cell, and through the synergistic effect of the top cover assembly and other parts of the battery cell, a substantial improvement in the overall performance of the battery cell is achieved. Specifically, the top cover assembly in the battery cell serves as an interface between the battery cell and the external environment, and is responsible for protecting the internal structure of the battery cell. The aforementioned top cover assembly achieves excellent sealing performance and enhanced connection strength through its structure and optimized manufacturing process. First of all, the excellent sealing performance of the top cover assembly effectively prevents the leakage of the electrolyte inside the battery cell, helps to extend the service life of the battery cell, and also significantly improves the safety and reliability of the battery cell. The enhanced connection strength of the top cover assembly ensures that the battery cell can still maintain structural integrity and stability when subjected to various mechanical and thermal stresses.

[0035] As can be seen from the foregoing, the top cover assembly manufacturing method of the present application adopts the injection molding technology, which replaces the traditional rivet structure, reduces the use of cover plate parts, and thus reduces the manufacturing cost. At the same time, an explosion-proof structure is formed on the top cover plate by scoring, replacing the traditional explosion-proof valve, which not only improves the safety and reliability of the product, but also reduces the number of parts and further simplifies the manufacturing process.

[0036] During the manufacturing process, the pole terminal is connected to the top cover plate to ensure electrical conductivity and structural stability. Then, the welding piece is welded to the inner welding surface of the pole terminal to enhance the firmness of the connection and optimize the current transmission path. Next, an injection molding space is constructed between the pole terminal, the top cover plate and the welding piece, and thermoplastic material is injected into the space to form an injection molding seal, which tightly connects the components together and improves the waterproof, dustproof and explosion-proof capabilities.

[0037] In addition, the present application designs a first through hole and a second through hole (arc strip shape) in the welding sheet, and aligns them with the injection hole in the top cover plate to ensure that the liquid can be smoothly and efficiently injected into the battery cell, while reducing the flow resistance and avoiding the problem of liquid leakage or poor flow. At the same time, injection molding channels and isolation parts are introduced to optimize the flow path of the injection molding material and prevent the injection molding material from flowing to the explosion-proof structure area, thereby ensuring the injection molding efficiency and product quality. The top cover assembly prepared by this method includes a pole terminal, a top cover plate, an injection molding seal and a welding sheet, wherein the injection molding seal tightly connects the components by injection molding to form a seamless and strong overall structure, thereby improving the sealing performance and connection strength of the top cover assembly.

[0038] Furthermore, the present application also provides a battery cell that integrates the aforementioned top cover assembly. The top cover assembly in the battery cell not only effectively prevents electrolyte leakage and improves the safety and reliability of the battery cell, but also ensures that the battery cell can maintain structural integrity and stability when subjected to various mechanical and thermal stresses through its excellent sealing performance and enhanced connection strength.

[0039] The above is only a specific implementation of the present application, and any other improvements made based on the concept of the present application are deemed to be within the protection scope of the present application.

Claims

1. A method for manufacturing a top cover assembly, characterized in that: include: Connect the pole terminal (100) to the top cover plate (200); Welding a welding sheet (400) to an inner welding surface of the pole terminal (100), and forming an injection molding space between the pole terminal (100), the top cover plate (200), and the welding sheet (400); Injection molding is performed in the injection molding space to form an injection molding seal (300) that tightly connects the top cover plate (200), the pole terminal (100) and the welding sheet (400); Wherein, the top cover plate (200) comprises an explosion-proof structure formed by means of notches (210).

2. The method for manufacturing a top cover assembly according to claim 1, characterized in that: A first through hole (410) is formed in the welding sheet (400) at a position corresponding to the explosion-proof structure, and an isolation piece corresponding to the explosion-proof structure is also formed before injection molding, the isolation piece is used to prevent the injection molding material from flowing toward the explosion-proof structure during the injection molding process.

3. The method for manufacturing a top cover assembly according to claim 1, characterized in that: The method further comprises the step of forming an injection molding channel in the terminal, and performing injection molding through the injection molding channel during the injection molding process.

4. The method for manufacturing a top cover assembly according to claim 1, characterized in that: The method also includes the step of forming a liquid injection hole (220) in the top cover plate (200).

5. The method for manufacturing a top cover assembly according to claim 4, characterized in that: A second through hole (420) is also formed in the welding sheet (400); when the welding sheet (400) is welded to the pole terminal (100), the injection hole (220) is aligned with the second through hole (420).

6. The method for manufacturing a top cover assembly according to claim 5, characterized in that: The second through hole (420) is an arc-shaped through hole.

7. The method for manufacturing a top cover assembly according to claim 1, characterized in that: The method further comprises the step of welding the busbar (500), wherein the busbar (500) is welded to the welding sheet (400).

8. A top cover assembly, characterized in that: It is obtained by the method for manufacturing a top cover assembly according to any one of claims 1 to 7, comprising: Pole terminal (100), top cover plate (200), injection molded seal (300), welding sheet (400); The injection-molded seal (300) is formed by injection molding in a space formed by the top cover plate (200), the welding sheet (400) and the pole terminal (100), and tightly connects the top cover plate (200), the pole terminal (100) and the welding sheet (400).

9. The top cover assembly according to claim 8, characterized in that: It comprises more than two pole terminals (100), each pole terminal (100) having a corresponding injection-molded seal (300) formed by injection molding.

10. A battery cell, characterized in that: Comprising a top cover assembly as described in any one of claims 8-9.

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