Battery explosion-proof cover cap and battery

Abstract

The utility model relates to a battery explosion -proof cap and battery, battery explosion -proof cap includes cap steel sheet and modified PP layer, still includes cap explosion -proof steel sheet and cap aluminium piece, cap explosion -proof steel sheet has a center cylinder that protrudes upwards, cap aluminium piece is the round sheet structure, and it is fixedly connected through laser welding mode in the top of cap explosion -proof steel sheet center cylinder, cap aluminium piece, cap explosion -proof steel sheet, modified PP layer and cap steel sheet are stacked from top to bottom in proper order and are compound into a complete cap structure. The utility model discloses a novel structure, simple manufacture, low cost and high reliability's battery explosion -proof cap and battery.

Description

Technical Field

[0001] This utility model relates to the field of battery safety technology, and in particular to an explosion-proof cap for cylindrical batteries and a battery including the cap. Background Technology

[0002] Safety has always been a core consideration in the manufacturing and use of rechargeable batteries, especially cylindrical lithium-ion batteries. Under abnormal conditions such as overcharging, short circuits, or thermal runaway, a large amount of gas can rapidly be generated inside the battery, leading to a sharp increase in pressure and posing a potential risk of casing rupture or even explosion. To address this challenge, the industry has long adopted a technology of precision laser grooving on the surface of the battery's steel casing. This process precisely controls the amount of material removed within a very small local area, reducing the thickness of the steel casing at the groove to an extremely low level, thus creating a pre-designed mechanical weak point. When the internal pressure exceeds the design threshold, the casing will preferentially rupture from this groove, achieving directional pressure relief.

[0003] However, this mature solution comes with a series of significant technological bottlenecks and economic challenges. The core pain point lies in the extreme precision and stability required of the laser processing system. To achieve a reliable burst value, strict control must be exercised over the uniformity and flatness of the steel substrate thickness, the positioning accuracy of the clamping fixture, and the fluctuations in the laser output power. Even minute deviations in any parameter can lead to uneven groove depth, resulting in excessively large dispersion in the burst pressure value, or even causing perforation and scrapping of the casing during processing. There is also the issue of high overall costs: the purchase cost of ultra-high power precision lasers is extremely expensive, and the annual maintenance, calibration, and replacement costs for vulnerable parts are equally substantial. Furthermore, because the residual material after grooving is extremely thin, it is highly susceptible to accidental damage due to minor impacts or stress during subsequent cleaning, transfer, assembly, and even the transportation of finished batteries, making it difficult to achieve a significant breakthrough in production yield, which typically remains at a certain level. Simultaneously, the high cost per unit is ultimately passed on to the total cost of the battery. Therefore, developing a new type of explosion-proof structure that can circumvent the inherent defects of laser grooving process and achieve a better balance between safety, economy and production yield has become an urgent problem to be solved in this field. Utility Model Content

[0004] The purpose of this invention is to overcome the above-mentioned defects of the laser-grooved explosion-proof method in the prior art, and to provide a battery explosion-proof cap and battery with novel structure, simple manufacturing, low cost and high reliability.

[0005] The objective of this utility model is achieved through the following technical solution: A battery explosion-proof cap includes a cap steel sheet and a modified PP layer, and also includes an explosion-proof cap steel sheet and a cap aluminum component; the explosion-proof cap steel sheet has an upwardly protruding central cylinder; the cap aluminum component is a circular plate structure, which is fixedly connected to the top of the central cylinder of the explosion-proof cap steel sheet by laser welding; the cap aluminum component, the explosion-proof cap steel sheet, the modified PP layer and the cap steel sheet are stacked and compounded from top to bottom to form a complete cap structure.

[0006] By integrating an innovative combination of an aluminum cap and an explosion-proof steel cap, a novel explosion-proof solution is provided, distinct from traditional laser grooving methods. The core advantage of this structural design lies in fundamentally avoiding the use of high-cost laser grooving, instead employing more stable and reliable mechanical stamping and laser welding technologies, significantly reducing the complexity of the production process and its dependence on equipment precision. The aluminum cap and the explosion-proof steel cap are laser-welded together to form a robust connection, which is then composited with a modified PP layer and the steel cap, ensuring the overall structure's sealing and mechanical strength. This layered composite structure not only simplifies the production process but also significantly improves product consistency, avoiding explosion-proof value deviations or breakage problems caused by factors such as fluctuations in steel shell thickness and unstable laser power in traditional processes. Simultaneously, this design provides the battery with a dual explosion-proof mechanism: firstly, initial pressure relief is achieved through the melting of the modified PP layer at high temperatures; secondly, complete pressure relief is achieved through the rupture of the pre-set pressure groove on the aluminum cap when internal pressure surges, greatly enhancing the battery's safety and reliability. Furthermore, by eliminating the steel casing grooving process, the battery production process is more efficient, and the overall manufacturing cost is effectively controlled, resulting in good economic benefits and promising industrialization prospects.

[0007] Preferably, the aluminum cap and the explosion-proof steel cap are connected by a ring-shaped laser weld.

[0008] By employing a ring-shaped laser weld to connect the aluminum cap and the explosion-proof steel cap, a highly sealed and robust connection can be achieved, effectively preventing electrolyte leakage or the intrusion of external contaminants. The ring-shaped weld structure helps to distribute stress evenly, improving the mechanical strength and pressure resistance of the connection area, ensuring that the explosion-proof structure can be activated according to predetermined conditions when the internal pressure of the battery increases. This connection method is a mature and highly stable technology, which is beneficial to improving production yield and product consistency.

[0009] Preferably, the upper surface of the cap aluminum part is provided with a groove, and the diameter of the annular laser weld is larger than the range of the groove.

[0010] A pressure groove is incorporated into the aluminum cap, and the diameter of the annular laser weld seam is larger than the pressure groove area, ensuring that the pressure groove area is effectively protected by the weld seam. This arrangement guides rupture at the pressure groove when abnormal internal battery pressure occurs, thus achieving a controllable and reliable pressure relief process. Simultaneously, the weld seam's enclosure of the pressure groove area enhances the structural stability of that region, reduces the risk of unexpected rupture, and further improves the accuracy and safety of explosion-proof actions.

[0011] Preferably, the groove is located within the top surface of the central cylinder of the explosion-proof steel sheet of the cap.

[0012] By strictly confining the pressure groove within the top surface of the central cylinder of the explosion-proof steel cap, it is ensured that the explosion-proof action always occurs within the support area of ​​the central cylinder. This design helps to more precisely control the conditions and location of the rupture, avoiding instability in explosion-proof performance due to deviations in the pressure groove position. Simultaneously, the structure of the central cylinder provides necessary mechanical support to the pressure groove area, preventing accidental damage from external forces during transportation or normal use.

[0013] Preferably, the shape of the pressure groove is one of a straight line, an arc, or a multi-segment shape.

[0014] The pressure groove can be made in various shapes, such as straight, arc, or multi-segment, providing greater flexibility for explosion-proof design. Different groove designs can correspond to different pressure trigger thresholds and rupture characteristics, meeting the specific explosion-proof performance requirements of various battery models and application scenarios. This design diversity allows the manufacturing process to be optimized according to actual needs, ensuring explosion-proof reliability while also considering production convenience and economy.

[0015] Preferably, a through hole is provided on the side wall of the central cylinder of the explosion-proof steel sheet of the cap, which is used to increase the contact area of ​​the solder during battery PACK welding.

[0016] A through-hole is made in the central cylindrical sidewall of the explosion-proof steel cap, which significantly increases the solder contact area during battery pack welding, improving welding quality and connection reliability. The larger welding area helps reduce contact resistance, improves current transmission efficiency, and enhances mechanical connection strength, reducing the risk of connection failure due to vibration or thermal expansion and contraction during use. This structural feature improves the overall performance and durability of the battery pack while ensuring explosion-proof functionality.

[0017] Preferably, both the cap steel sheet and the cap explosion-proof steel sheet are made of stainless steel.

[0018] Both the cap steel sheet and the explosion-proof steel sheet are made of stainless steel. The excellent mechanical strength, corrosion resistance, and consistent processing properties of stainless steel ensure the stability and durability of the overall cap structure. Using the same material simplifies the production process, especially during pretreatment passivation and hot-pressing composite processes, allowing for consistent process parameters, thereby improving production yield and product consistency, and reducing the risk of quality fluctuations.

[0019] Preferably, a battery includes a steel casing and a battery cell, with the opening of the steel casing sealed with the aforementioned battery explosion-proof cap.

[0020] Batteries encapsulated with the aforementioned explosion-proof cap possess reliable explosion-proof safety characteristics, while avoiding various problems associated with laser-grooved steel casings in traditional batteries. This battery structure simplifies the manufacturing process, reduces production costs, improves product consistency and reliability, and provides a safer and more efficient guarantee for battery use.

[0021] Preferably, the inner or outer side of the steel shell does not need to be laser-grooved.

[0022] Thanks to the innovative explosion-proof cap structure, the battery steel casing itself no longer requires laser grooving, completely avoiding the yield issues, equipment investment, and high costs associated with the grooving process. The simplified steel casing structure not only reduces production costs but also improves the overall strength and sealing of the casing, reducing potential weak points caused by grooving and enhancing the battery's safety and reliability.

[0023] Preferably, the melting temperature of the modified PP layer is lower than the cracking temperature of the aluminum cap.

[0024] By ensuring the melting temperature of the modified PP layer is lower than the cracking temperature of the aluminum cap, an ordered dual explosion-proof mechanism is formed. When the battery temperature rises abnormally, the modified PP layer melts and fails first, providing an initial pressure relief channel; if the temperature and pressure continue to rise, the aluminum cap will then crack to achieve complete pressure relief. This staged activation explosion-proof design provides multi-layered safety protection, significantly reducing the risk of violent battery explosions.

[0025] The advantages of this utility model compared to the prior art are: The battery explosion-proof cap and battery proposed in this utility model, through their innovative structural design, demonstrate multiple potential advantages and provide a new approach to solving the problems faced by traditional technologies.

[0026] Firstly, the core innovation of this structure lies in transferring the explosion-proof function from the battery steel casing to a separately designed composite cap. This fundamental change eliminates the need for the battery steel casing itself to undergo the complex and costly laser grooving process. Instead, the key component in the cap—the aluminum part of the cap—can be formed and grooved in one piece using a mature stamping process. Stamping is characterized by high efficiency, low cost, relatively simple mold structure, and good material adaptability, which helps to significantly reduce the unit manufacturing cost and equipment investment threshold of the explosion-proof structure.

[0027] Secondly, in terms of reliability, this structure may exhibit better stability. The pre-formed mechanical strength of stamped aluminum parts is typically higher than the residual thickness of laser-grooved steel shells. This means it has stronger resistance to physical impacts during the production process, potentially reducing accidental breakage from minor bumps and creating conditions for improved production yield. Simultaneously, this structure may be less sensitive to fluctuations in raw material thickness, providing a wider production process window and helping to ensure consistent product performance.

[0028] Furthermore, this design provides a dual-action pressure relief mechanism, potentially enhancing the redundancy of safety protection. The first layer of protection comes from the modified PP adhesive layer, which softens and melts when the battery's internal temperature rises abnormally, initially breaking the seal and forming an initial pressure relief channel. If this stage fails to effectively suppress the continued increase in internal pressure, the rising pressure will act on the aluminum cap, causing it to rupture from the pre-set pressure groove, thus initiating a larger-scale pressure relief. This phased response design concept aims to release internal pressure more gently and controllably, reducing the likelihood of a violent battery rupture.

[0029] Furthermore, the through-hole design on the sidewall of the central pillar of the explosion-proof steel cap may bring additional benefits in the subsequent battery pack welding process. This through-hole structure can provide additional flow space and adhesion area for the solder, which is expected to result in larger solder joints, stronger mechanical connections, and more stable electrical contacts, thereby improving the overall connection reliability and long-term stability of the battery module.

[0030] In summary, this utility model, through structural innovation, aims to provide a battery explosion-proof solution that may have lower overall cost, higher production yield, wider process adaptability, and multiple safety protections. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is an exploded view of the battery explosion-proof cap of Embodiment 1 of this utility model.

[0033] Figure 2 This is a cross-sectional view of the battery explosion-proof cap of Embodiment 1 of this utility model.

[0034] Figure 3 for Figure 2 A magnified view of region A in the middle.

[0035] Figure 4 This is an exploded view of the battery in Embodiment 2 of this utility model.

[0036] Figure 5 This is a cross-sectional view of the battery in Embodiment 2 of this utility model.

[0037] Figure 6 for Figure 5 A magnified view of region B in the middle.

[0038] Labeling Explanation: 1. Cap steel sheet, 2. Modified PP layer, 3. Cap explosion-proof steel sheet, 31. Center cylinder, 32. Through hole, 4. Cap aluminum part, 41. Pressure groove, 5. Battery, 6. Battery cell. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0040] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0041] It should be noted that similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of the embodiments of this application, it should be understood that the terms "upper," "lower," "left," "right," "vertical," "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figures, or the orientation or positional relationship commonly used when the product of this application is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0042] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0043] The technical solutions in this application will now be described with reference to the accompanying drawings. Example

[0044] This embodiment provides a battery explosion-proof cap, including a cap steel sheet 1 and a modified PP layer 2, as well as a cap explosion-proof steel sheet 3 and a cap aluminum part 4; the cap explosion-proof steel sheet 3 has an upwardly protruding central cylinder 31; the cap aluminum part 4 is a circular plate structure, which is fixedly connected to the top of the central cylinder 31 of the cap explosion-proof steel sheet 3 by laser welding; the cap aluminum part 4, the cap explosion-proof steel sheet 3, the modified PP layer 2 and the cap steel sheet 1 are stacked and compounded from top to bottom to form a complete cap structure.

[0045] By integrating the aluminum cap 4 and the explosion-proof steel cap 3 in an innovative combination, a novel explosion-proof solution is provided, distinct from traditional laser grooving methods. The core advantage of this structural design lies in fundamentally avoiding the use of high-cost laser grooving, instead employing more stable and reliable mechanical stamping and laser welding technologies, significantly reducing the complexity of the production process and its dependence on equipment precision. The aluminum cap 4 and the explosion-proof steel cap 3 form a stable connection through laser welding, and are then composited with the modified PP layer 2 and the steel cap 1, ensuring the overall structure's sealing and mechanical strength. This layered composite structure not only simplifies the production process but also significantly improves product consistency, avoiding explosion-proof value deviations or breakage problems caused by factors such as steel shell thickness fluctuations and unstable laser power in traditional processes. Simultaneously, this design provides the battery with a dual explosion-proof mechanism: firstly, initial pressure relief is achieved through the melting of the modified PP layer 2 at high temperatures; secondly, complete pressure relief is achieved through the rupture of the pre-set pressure groove 41 on the aluminum cap 4 when internal pressure suddenly increases, greatly enhancing the battery's safety and reliability. Furthermore, by eliminating the steel casing grooving process, the battery production process is more efficient, and the overall manufacturing cost is effectively controlled, resulting in good economic benefits and promising industrialization prospects.

[0046] In this embodiment, the aluminum cap 4 and the explosion-proof steel cap 3 are connected by a ring-shaped laser weld.

[0047] By employing a ring-shaped laser weld to connect the aluminum cap part 4 and the explosion-proof steel sheet 3, a highly sealed and robust connection can be achieved between the two, effectively preventing electrolyte leakage or the intrusion of external contaminants. The ring-shaped weld structure helps to distribute stress evenly, improves the mechanical strength and pressure resistance of the connection, and ensures that the explosion-proof structure can be activated according to predetermined conditions when the internal pressure of the battery increases. This connection method is a mature technology with high stability, which is beneficial to improving production yield and product consistency.

[0048] In this embodiment, the upper surface of the cap aluminum part 4 is provided with a pressure groove 41, and the diameter of the annular laser weld is larger than the range of the pressure groove 41.

[0049] A pressure groove 41 is provided on the aluminum cap component 4, and combined with the design that the diameter of the annular laser weld is larger than the range of the pressure groove 41, the area of ​​the pressure groove 41 is within the effective protection range of the weld. This layout can guide the rupture to occur at the pressure groove 41 when the internal pressure of the battery is abnormal, thereby achieving a controllable and reliable pressure relief process. At the same time, the weld surrounding the area of ​​the pressure groove 41 enhances the structural stability of this area, reduces the risk of unexpected rupture, and further improves the accuracy and safety of the explosion-proof action.

[0050] In this embodiment, the pressure groove 41 is located within the top surface of the central cylinder 31 of the explosion-proof steel sheet 3.

[0051] By strictly confining the pressure groove 41 within the top surface of the central cylinder 31 of the explosion-proof steel sheet 3, it is ensured that the explosion-proof action always occurs within the support area of ​​the central cylinder 31. This design helps to more precisely control the conditions and location of the rupture, avoiding instability in explosion-proof performance due to deviations in the position of the pressure groove 41. At the same time, the structure of the central cylinder 31 provides necessary mechanical support for the pressure groove 41 area, preventing accidental damage due to external forces during transportation or normal use.

[0052] In this embodiment, the shape of the pressure groove 41 is one of a straight line, an arc, or a multi-segment shape.

[0053] The pressure groove 41 can be in various shapes, such as straight, arc, or multi-segment, providing greater flexibility for explosion-proof design. Different groove designs can correspond to different pressure trigger thresholds and rupture characteristics, meeting the specific explosion-proof performance requirements of various battery models and application scenarios. This design diversity allows the manufacturing process to be optimized according to actual needs, ensuring explosion-proof reliability while also considering production convenience and economy.

[0054] In this embodiment, a through hole 32 is provided on the side wall of the central cylinder 31 of the explosion-proof steel sheet 3. The through hole 32 is used to increase the contact area of ​​the solder during battery PACK welding.

[0055] A through hole 32 is made in the side wall of the central cylinder 31 of the explosion-proof steel cap 3, which significantly increases the solder contact area during battery PACK welding, improving welding quality and connection reliability. The larger welding area helps reduce contact resistance, improve current transmission efficiency, and enhance mechanical connection strength, reducing the risk of connection failure due to vibration or thermal expansion and contraction during use. This structural feature improves the overall performance and durability of the battery pack while ensuring explosion-proof functionality.

[0056] In this embodiment, both the cap steel sheet 1 and the cap explosion-proof steel sheet 3 are made of stainless steel.

[0057] Both the cap steel sheet 1 and the cap explosion-proof steel sheet 3 are made of stainless steel. The excellent mechanical strength, corrosion resistance, and process consistency of stainless steel ensure the stability and durability of the overall cap structure. Using the same material simplifies the production process, especially during pretreatment passivation and hot-pressing composite processes, allowing for consistent process parameters, thereby improving production yield and product consistency, and reducing the risk of quality fluctuations. Example

[0058] This embodiment discloses a battery, including a steel shell 5 and a battery cell 6. The opening of the steel shell 5 is sealed with a battery explosion-proof cap as described in Embodiment 1.

[0059] The battery encapsulated with the explosion-proof cap described in Example 1 possesses reliable explosion-proof safety characteristics, while avoiding various problems associated with laser-grooved steel casings of traditional batteries. This battery structure simplifies the manufacturing process, reduces manufacturing costs, improves product consistency and reliability, and provides a safer and more efficient guarantee for battery use.

[0060] In this embodiment, laser grooving is not required on the inner or outer side of the steel shell 5.

[0061] Thanks to the innovative explosion-proof cap structure, the battery steel casing itself no longer requires laser grooving, completely avoiding the yield issues, equipment investment, and high costs associated with the grooving process. The simplified steel casing structure not only reduces production costs but also improves the overall strength and sealing of the casing, reducing potential weak points caused by grooving and enhancing the battery's safety and reliability.

[0062] In this embodiment, the melting temperature of the modified PP layer 2 is lower than the cracking temperature of the cap aluminum part 4.

[0063] By ensuring that the melting temperature of the modified PP layer 2 is lower than the cracking temperature of the aluminum cap 4, an orderly dual explosion-proof mechanism is formed. When the battery temperature rises abnormally, the modified PP layer 2 melts and fails first, providing an initial pressure relief channel; if the temperature and pressure continue to rise, the aluminum cap 4 will then crack to achieve complete pressure relief. This staged activation explosion-proof design provides multi-layered safety protection, greatly reducing the risk of violent battery explosions.

[0064] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A battery explosion-proof cap, comprising a cap steel sheet (1) and a modified PP layer (2), characterized in that, It also includes explosion-proof steel sheet cap (3) and aluminum cap cap (4); The explosion-proof steel sheet (3) with the cap has an upwardly protruding central cylinder (31); The aluminum cap part (4) is a circular plate structure, which is fixedly connected to the top of the central cylinder (31) of the explosion-proof steel plate (3) of the cap by laser welding; The cap aluminum part (4), the cap explosion-proof steel sheet (3), the modified PP layer (2) and the cap steel sheet (1) are stacked and compounded from top to bottom to form a complete cap structure.

2. The battery explosion-proof cap according to claim 1, characterized in that, The aluminum cap (4) and the explosion-proof steel cap (3) are connected by a ring-shaped laser weld.

3. A battery explosion-proof cap according to claim 2, characterized in that, The upper surface of the cap aluminum part (4) is provided with a pressure groove (41), and the diameter of the annular laser weld is larger than the range of the pressure groove (41).

4. A battery explosion-proof cap according to claim 3, characterized in that, The pressure groove (41) is located within the top surface of the central cylinder (31) of the explosion-proof steel sheet (3) of the cap.

5. A battery explosion-proof cap according to claim 3 or 4, characterized in that, The shape of the pressure groove (41) is one of a straight line, a circular arc, or a multi-segment shape.

6. A battery explosion-proof cap according to claim 1, characterized in that, The explosion-proof steel sheet (3) with the cap has a through hole (32) on the side wall of the central cylinder (31), which is used to increase the contact area of ​​the solder during battery PACK welding.

7. A battery explosion-proof cap according to claim 1, characterized in that, Both the cap steel sheet (1) and the cap explosion-proof steel sheet (3) are made of stainless steel.

8. A battery explosion-proof cap according to claim 1, characterized in that, The melting temperature of the modified PP layer (2) is lower than the cracking temperature of the cap aluminum part (4).

9. A battery comprising a steel casing (5) and a battery cell (6), characterized in that, The opening of the steel shell (5) is encapsulated with a battery explosion-proof cap as described in any one of claims 1 to 7.

10. A battery according to claim 9, characterized in that, The inner or outer side of the steel shell (5) does not need to be laser-grooved.

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