Top cover assembly and battery cell

Abstract

According to the top cover assembly and the battery cell, an upper plastic structure and a top cover sheet structure are optimized, and a matching structure of a first bulge and a first groove on the contact surface of a lower plastic part and a top cover sheet is designed, so that the risk that an electrolyte enters a gap of a sealing ring is effectively reduced, the connection strength is enhanced, and electrolyte permeation is prevented. Meanwhile, a nick anti-explosion structure is arranged in the top cover piece body, a traditional independent anti-explosion valve is replaced, the structure is simplified, and the anti-explosion response speed and reliability are improved. Besides, the top cover assembly comprises more than two pole terminals, and each pole terminal is provided with an independent sealing ring and an independent plastic part, so that sufficient sealing protection is ensured. In specific implementation, the first protrusions and the second protrusions are staggered in the vertical direction, and the structural stability of the top cover assembly is enhanced through the arrangement of the first protrusions and the design that the sizes of the first protrusions are gradually increased. In addition, by means of the size design of the first protrusion and the first groove, assembly convenience and the sealing effect can be guaranteed.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a top cover assembly and a battery cell. Background Technology

[0002] In the field of battery technology, especially in the design and manufacturing of battery cells, the top cover assembly is a key component ensuring the safe and efficient operation of the battery. Traditional battery cell top cover assemblies typically employ a riveted structure, mechanically connecting various components within the cover plate. In this structure, T-shaped sealing rings are widely used between the rivets and the cover plate to achieve insulation. However, in practical applications, this traditional structure has revealed certain problems. During the riveting process, the T-shaped sealing ring can deform under external pressure, often leaving gaps between the rivets and the lower plastic layer. When the battery cell moves, electrolyte can seep into these gaps, corroding the sealing ring and causing it to lose its proper sealing and insulation effects. This not only leads to a decrease in battery cell performance but may also cause safety issues. Furthermore, due to electrolyte seepage, the battery cell cover plate may carry a weak electrical charge, affecting the normal use of the battery cell.

[0003] In addition to the aforementioned issues, traditional battery cells also face challenges in the design and application of explosion-proof valves. Explosion-proof valves are crucial components for controlling internal battery pressure and ensuring cell safety. However, because battery covers and explosion-proof valves are typically made from thin-walled stamped parts, impurities such as lubricating oil and cleaning fluid can easily remain during processing. These impurities readily vaporize and rise to the surface of the molten pool during the welding process of the explosion-proof valve, especially under high-power-density laser light, generating significant spatter and leaving pits or pores on the weld surface. This not only affects the weld quality but may also reduce the sealing performance of the explosion-proof valve, thereby impacting the overall safety of the battery cell.

[0004] To address these issues, the industry has made some progress. For example, some new power battery top cover structures employ more advanced connection methods and sealing designs, such as using a combination of plastic rings and connecting rings to compress the sealing ring, thereby ensuring a tight seal. Furthermore, new materials and processes have been introduced into the design of explosion-proof valves to improve their corrosion resistance and welding quality.

[0005] However, despite some progress, the field of battery technology still faces some problems that need to be solved. These include how to reduce the defect rate in the welding process of explosion-proof valves, how to better deal with electrolyte penetration, and the continuous exploration and innovation of top cover component design schemes to improve their safety, reliability and durability. These remain important issues in the current field of battery technology. Utility Model Content

[0006] The purpose of this application is to provide a top cover assembly that can reduce the entry of electrolyte into the gaps of the sealing ring by changing the upper plastic structure and the top cover sheet structure, and can also reduce the impact of independently installed explosion-proof valve on the product. The top cover assembly of this application specifically includes a pole terminal, an upper plastic part, a top cover sheet, a sealing ring, a lower plastic part and a manifold, wherein the pole terminal, the upper plastic part, the top cover sheet, the sealing ring, the lower plastic part and the manifold are connected by rivets;

[0007] The lower plastic part has a first protrusion on the surface that contacts the top cover sheet, and the top cover sheet has a first groove at the position corresponding to the first protrusion on the surface that contacts the lower plastic part.

[0008] The top cover plate has an explosion-proof structure in its body, and the explosion-proof structure is formed by grooves on the body.

[0009] The sealing ring is fitted onto the pole terminal.

[0010] In one embodiment, the device includes two or more of the aforementioned pole terminals, each of which has a corresponding sealing ring.

[0011] In one embodiment, the body of the explosion-proof structure is thinned, and the explosion-proof structure lies in the plane of the body of the top cover plate.

[0012] In one embodiment, the surface of the upper plastic part that contacts the top cover sheet has a second protrusion, and the surface of the top cover sheet that contacts the upper plastic part has a second groove at a position corresponding to the second protrusion.

[0013] In one embodiment, the positions of the first protrusion and the second protrusion are offset in the vertical direction.

[0014] In one embodiment, a plurality of the first protrusions are included.

[0015] In one embodiment, the multiple first protrusions are of different sizes.

[0016] In one embodiment, the size of the plurality of first protrusions gradually increases in the direction toward the center of the pole terminal.

[0017] In one embodiment, the height of the first protrusion is 1-5% of the depth of the first groove, and the width of the first groove is 2-10% of the width of the first protrusion.

[0018] In addition, this application also provides a battery cell that includes the aforementioned top cover assembly.

[0019] Compared with the prior art, this application has the following beneficial effects:

[0020] The top cover assembly of this application reduces electrolyte penetration and improves sealing performance. By providing a first protrusion on the surface of the lower plastic part that contacts the top cover sheet, and providing a first groove at the corresponding position of the top cover sheet, the two can form a tight fit after riveting, effectively reducing the corrosion problem of the sealing ring caused by electrolyte penetration. Through the improvement of the physical structure, the entry of electrolyte into the gap between the sealing ring and the lower plastic part is minimized, thereby extending the service life of the sealing ring and improving the overall sealing performance of the battery.

[0021] Furthermore, this application employs a notch design instead of the traditional explosion-proof valve structure, achieving effective release of internal battery pressure with a simplified structure. The notch design is located on the top cover plate itself and can be combined with thinning treatment to automatically rupture when the internal battery pressure is too high, achieving the purpose of pressure relief. This design not only simplifies the battery structure and reduces the impact of the explosion-proof valve on the product, but also improves the safety and reliability of the battery.

[0022] This application retains the riveted connection method between the terminal block, upper plastic part, top cover, sealing ring, lower plastic part, and busbar. Through subtle structural improvements and optimizations, the top cover assembly of this application is compatible with current production lines without requiring extensive modifications. It achieves a secure connection between components and reduces the risk of electrolyte leakage due to cell movement. By meticulously designing the dimensional and positional relationships between the first protrusion and the first groove, and the second protrusion and the second groove, assembly convenience and leakage prevention are further enhanced, further improving the overall quality and reliability of the battery. In summary, the top cover assembly of this application, through a series of new improvements, achieves enhanced battery safety and stability. Attached Figure Description

[0023] Figure 1 This is an exploded structural diagram of the top cover assembly in a specific embodiment of this application;

[0024] Figure 2 This is a partial structural diagram of the pole terminal position of the top cover assembly in a specific embodiment of this application;

[0025] Figure 3 This is a partial structural diagram of the explosion-proof structure of the top cover assembly in a specific embodiment of this application.

[0026] Explanation of reference numerals in the attached drawings: 100, pole terminal; 200, upper plastic part; 300, top cover plate; 310, first groove; 320, notch; 400, sealing ring; 410, gap; 500, lower plastic part; 510, first protrusion; 600, busbar; 700, rivet. Detailed Implementation

[0027] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0028] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0029] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0030] Traditional battery cell top cover assemblies often use a rivet 700 structure for mechanical connection and rely on a T-shaped sealing ring 400 for insulation and sealing. However, this structure faces challenges in practical applications such as electrolyte penetration, corrosion of the sealing ring 400, and welding defects in the explosion-proof valve. To solve these problems, this application focuses on a novel top cover assembly and the battery cell used in it. This top cover assembly, by changing the upper plastic structure and the structure of the top cover sheet 300, effectively reduces the risk of electrolyte entering the gap 410 between the sealing ring 400 and the lower plastic part 500. Simultaneously, it uses a notched 320 design instead of the traditional explosion-proof valve structure, further improving the safety and stability of the battery. This not only simplifies the battery structure but also improves manufacturing precision and consistency. Please refer to [link / reference]. Figures 1 to 3As shown, in one embodiment of this application, the top cover assembly specifically includes a pole terminal 100, an upper plastic part 200, a top cover sheet 300, a sealing ring 400, a lower plastic part 500, and a manifold 600. The pole terminal 100, the upper plastic part 200, the top cover sheet 300, the sealing ring 400, the lower plastic part 500, and the manifold 600 are connected by rivets 700. The surface of the lower plastic part 500 that contacts the top cover sheet 300 has a first protrusion 510. The surface of the top cover sheet 300 that contacts the lower plastic part 500 has a first groove 310 at a position corresponding to the first protrusion 510. The body of the top cover sheet 300 is provided with an explosion-proof structure, and the explosion-proof structure is formed by a groove 320 on the body. The sealing ring 400 is sleeved on the pole terminal 100.

[0031] The top cover assembly specifically includes multiple components such as the pole terminal 100, upper plastic part 200, top cover plate 300, sealing ring 400, lower plastic part 500, and manifold 600. These components are connected by rivets 700 to form a stable whole, consistent with existing technology, and compatible with current production lines without major modifications. On the contact surface between the lower plastic part 500 and the top cover plate 300, a matching structure of a first protrusion 510 and a first groove 310 is specially designed, specifically as follows... Figure 2 As shown, this application features a first groove 310 pressed into the top cover plate 300 and a first protrusion 510 formed by injection molding of the lower plastic part 500. These components work together to prevent electrolyte from entering the gap 410 between the sealing ring 400 and the lower plastic part. This design not only enhances the connection strength between the lower plastic part 500 and the top cover plate 300, preventing loosening or detachment due to vibration or impact, but also effectively reduces the gap between them, thus preventing the penetration of harmful substances such as electrolyte, and further improving battery safety. The matching structure of the protrusion and groove on the lower plastic part 500 and the top cover plate 300 enhances the tightness of the connection, preventing electrolyte penetration. The tight fit between the protrusion and groove prevents deformation of the lower plastic part 500 relative to its original design during riveting, effectively preventing the penetration of harmful substances such as electrolyte and ensuring the cleanliness and safety of the battery's internal environment.

[0032] The top cover plate 300 incorporates an explosion-proof structure within its body. This structure is not a traditional independent explosion-proof valve, but rather a groove 320 directly formed on the body, as detailed below. Figure 3As shown, the explosion-proof valve in the prior art is eliminated. Instead, a notch 320 is used in the top cover plate 300 to replace the existing explosion-proof valve. When the cell pressure is excessive, the pressure opens the notch 320 to release pressure. That is, when the internal pressure of the battery abnormally increases, the notch 320 will rupture first, thus quickly releasing the internal pressure and preventing the battery from exploding. This design simplifies the structure of the top cover assembly, reduces manufacturing costs, and improves the response speed and reliability of the explosion-proof structure. By eliminating the traditional independent explosion-proof valve structure and directly forming the notch 320 on the top cover plate 300 body as the explosion-proof structure, not only is the structure of the top cover assembly simplified, but manufacturing costs are also reduced and production efficiency is improved. This allows the top cover assembly to respond quickly to abnormal internal battery pressure, releasing the internal pressure and preventing the battery from exploding, thus improving the battery's safety performance.

[0033] Specifically, the top cover assembly of this application includes two or more of the aforementioned terminal posts 100, each of which has a corresponding sealing ring 400 and a lower plastic part 500 including a protrusion. Each terminal post 100 serves as a component connecting the battery to an external circuit, and its corresponding sealing ring 400 plays a crucial role in isolating the electrolyte, preventing gas leakage, and maintaining the stability of the battery's internal environment. By equipping each terminal post 100 with an independent sealing ring 400 and a lower plastic part 500, each connection point can be adequately sealed, thereby reducing the risk of battery failure due to poor sealing. Furthermore, this design of multiple terminal posts 100 and independent sealing rings 400 provides strong assurance for the stable operation of the battery under complex operating conditions. During battery charging and discharging, due to internal chemical reactions and temperature changes, the terminal posts 100 may be subjected to varying degrees of thermal and mechanical stress. The independent design can mitigate the impact of these stresses on sealing performance to a certain extent.

[0034] Specifically, the explosion-proof structure of this application undergoes a thinning process, and the explosion-proof structure lies within the plane of the main body of the top cover plate 300. The thinning process is not limited to traditional thickness reduction but encompasses multiple dimensions, including material removal, structural optimization, and strength adjustment, aiming to achieve a lightweight and efficient explosion-proof structure. Specifically, the explosion-proof structure is embedded within the plane of the main body of the top cover plate 300, forming an integrated structure with the surrounding materials. This maintains the overall flatness of the top cover plate 300 while providing it with a specific pressure relief function. During the material reduction process, precise thickness adjustments are made to the explosion-proof structure area using precision machining or laser cutting technology. This ensures stability under normal operating pressure and allows for rapid response and rupture when internal pressure abnormally increases, releasing the internal high-pressure gas. This design also brings another important technical effect: improved sensitivity of the explosion-proof structure. Because the thinned explosion-proof structure area is more prone to deformation under pressure, it can change in a shorter time, releasing internal pressure more quickly when the critical rupture condition is reached, further enhancing battery safety. The overall strength of the reinforced top cover plate 300 can be better maintained. Although the explosion-proof structure area has undergone material reduction treatment, the overall strength of the top cover plate 300 has not been affected by the tight connection with the surrounding materials and the integrated design.

[0035] To further improve sealing performance, the upper plastic part 200 has a second protrusion on the surface in contact with the top cover plate 300, and the top cover plate 300 has a second groove at a position corresponding to the second protrusion on the surface in contact with the upper plastic part 200. The upper plastic part 200 and the top cover plate 300 also employ a mating mechanism on their contact surfaces. The upper plastic part 200 has a second protrusion on its contact surface, while the top cover plate 300 has a second groove at the corresponding position in contact with the upper plastic part 200 that matches the second protrusion. This convex-concave mating design enhances the connection stability between the two and ensures a tight fit. In terms of design details, the shape, size, and position of the second protrusion and the second groove have been calculated to ensure a perfect match, forming a lock-like structure. This not only improves the overall strength of the top cover assembly but also allows it to maintain structural stability and integrity when facing external forces such as vibration and impact.

[0036] Specifically, the first protrusion 510 and the second protrusion are vertically offset. This design avoids direct physical conflict between them and ensures the compactness and functional integrity of the internal structure of the top cover assembly. The first protrusion 510 positions and seals the lower plastic part 500 and the top cover sheet 300 to prevent electrolyte penetration, while the second protrusion mainly serves the function of facilitating the connection between the top cover sheet 300 and the upper plastic part 200, such as enhancing connection stability. By arranging them vertically offset, structural fragility caused by structural overlap is avoided (if they were placed in the same position, the top cover sheet 300 might be too thin), ensuring smooth assembly and efficient operation of the top cover assembly. Due to the vertical separation of the first protrusion 510 and the second protrusion, higher manufacturing precision is required, promoting the optimization of the manufacturing process, improving product quality and reliability, allowing their respective functions to be better utilized, and jointly enhancing the structural stability of the top cover assembly and improving the battery's vibration and impact resistance.

[0037] Specifically, it includes multiple first protrusions 510. The arrangement of multiple first protrusions 510 makes the connection between the top cover 300 and other components inside the battery more secure and stable, effectively preventing loosening or detachment due to vibration or impact, and improving the overall reliability of the battery. The layout of multiple first protrusions 510 facilitates alignment during manufacturing, eliminating the need for additional alignment structures. The presence of multiple first protrusions 510, through their reasonable distribution, improves the overall structural strength of the top cover 300, enabling it to maintain structural integrity and stability when facing changes.

[0038] Specifically, the multiple first protrusions 510 have different sizes. During the riveting process, different displacements may occur. To avoid structural failure of the protrusions and grooves under certain circumstances, the multiple first protrusions 510 are each set to have different sizes. This can prevent failure under certain circumstances and further improve the sealing stability of the structure. In a specific embodiment, the size of the multiple first protrusions 510 gradually increases in the direction towards the center of the pole terminal 100. The gradual increase in the size of the first protrusions 510 allows the top cover plate 300 to form a more robust support structure in the direction towards the center of the pole terminal 100, enhancing the overall structural stability of the top cover assembly.

[0039] Specifically, the height of the first protrusion 510 is 1-5% of the depth of the first groove 310, and the width of the first groove 310 is 2-10% of the width of the first protrusion 510. Since the protrusion will deform under pressure, the dimensions of the first protrusion 510 and the first groove 310 are further designed to accommodate these deformations. This design ensures that the first protrusion 510 is completely contained within the first groove 310 during deformation and will not move to other positions. Furthermore, the aforementioned dimensional design greatly improves the ease of assembly. Additionally, because the height-to-width ratio of the protrusion and groove is appropriate, their contact area is maximized, significantly improving the sealing effect.

[0040] In addition, this application also provides a battery cell that includes the aforementioned top cover assembly. A battery cell formed using the aforementioned top cover assembly can reduce the ingress of electrolyte into the gap 410 of the sealing ring 400, and can also effectively release the internal pressure of the battery with a simple structure, improving performance while significantly reducing manufacturing difficulty.

[0041] As described above, this application proposes a novel top cover assembly and the battery cell used in it, aiming to solve problems such as electrolyte penetration, sealing ring corrosion, and welding defects in explosion-proof valves in traditional battery cell top cover assemblies. Firstly, a pairing structure of a first protrusion and a first groove is designed on the contact surface between the lower plastic component and the top cover sheet in the top cover assembly. This design not only enhances the connection strength between the two but also effectively reduces the risk of electrolyte entering the sealing ring gap, thereby improving the battery's safety performance. Simultaneously, the tight fit between the first protrusion and the first groove prevents deformation of the lower plastic component during riveting, further preventing the penetration of harmful substances such as electrolyte.

[0042] Secondly, the top cover body incorporates a grooved explosion-proof structure, replacing the traditional independent explosion-proof valve. When the internal pressure of the battery abnormally increases, the grooved area will rupture first, rapidly releasing the internal pressure and preventing the battery from exploding. This design simplifies the structure of the top cover assembly, reduces manufacturing costs, improves production efficiency, and enables the top cover assembly to respond quickly to abnormal internal battery pressure.

[0043] Furthermore, the top cover assembly of this application includes two or more terminal posts, each equipped with an independent sealing ring and a lower plastic component. This design ensures that each connection point is adequately sealed, reducing the risk of battery failure due to poor sealing. Simultaneously, the multi-terminal post design and independent sealing rings provide strong support for the stable operation of the battery under complex operating conditions.

[0044] In a specific embodiment, the positions of the first protrusion and the second protrusion are staggered in the vertical direction, avoiding structural fragility caused by structural overlap and ensuring the compactness and functional integrity of the internal structure of the top cover assembly. Simultaneously, the arrangement of multiple first protrusions and their gradually increasing dimensions towards the center of the terminal post further enhance the structural stability of the top cover assembly. The height of the first protrusion is designed to be 1%-5% of the depth of the first groove, while the width of the first groove is 2%-10% of the width of the first protrusion. This dimensional design ensures that the protrusion can be completely accommodated in the groove during deformation, improving assembly convenience and sealing effect. In summary, the top cover assembly and the battery cell used in this application, through a series of technological innovations, effectively solve the problems existing in traditional battery cell top cover assemblies, improve battery safety and stability, simplify battery structure, and improve manufacturing precision and consistency, showing broad application prospects.

[0045] The above is only one specific implementation of this application, and any other improvements made based on the concept of this application shall be considered within the scope of protection of this application.

Claims

1. A cap assembly, characterized by, The top cover assembly comprises a pole terminal (100), an upper plastic part (200), a top cover sheet (300), a sealing ring (400), a lower plastic part (500) and a busbar (600), wherein the pole terminal (100), the upper plastic part (200), the top cover sheet (300), the sealing ring (400), the lower plastic part (500) and the busbar (600) are connected by a rivet (700); The lower plastic part (500) has a first protrusion (510) on a surface in contact with the top cover sheet (300), and the top cover sheet (300) has a first groove (310) at a position corresponding to the first protrusion (510) on a surface in contact with the lower plastic part (500); The top cover sheet (300) has an anti-explosion structure formed by a notch (320) on the body of the top cover sheet (300); The sealing ring (400) is sleeved on the pole terminal (100).

2. The roof assembly of claim 1, wherein, The top cover assembly comprises two or more pole terminals (100), and each pole terminal (100) has a corresponding sealing ring (400).

3. The roof assembly of claim 1, wherein, The anti-explosion structure is formed by thinning the body at the anti-explosion structure.

4. The roof assembly of claim 1, wherein, The upper plastic part (200) has a second protrusion on a surface in contact with the top cover sheet (300), and the top cover sheet (300) has a second groove at a position corresponding to the second protrusion on a surface in contact with the upper plastic part (200).

5. The roof assembly of claim 4, wherein, The positions of the first protrusion (510) and the second protrusion are staggered in the vertical direction.

6. The roof assembly of claim 1, wherein, The top cover assembly comprises a plurality of first protrusions (510).

7. The roof assembly of claim 6, wherein, The sizes of the plurality of first protrusions (510) are different.

8. The roof assembly of claim 7, wherein, The sizes of the plurality of first protrusions (510) gradually increase in a direction towards the center of the pole terminal (100).

9. The roof assembly of claim 1, wherein, The height of the first protrusion (510) is 1-5% of the depth of the first groove (310), and the width of the first groove (310) is 2-10% of the width of the first protrusion (510).

10. An electric cell characterized by The top cover assembly comprises the top cover assembly of any one of claims 1-9.

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