Cap assembly and cylindrical battery

Abstract

The utility model relates to the technical field of cylindrical battery structures, and provides a cap assembly and a cylindrical battery, the cap assembly comprises a top cover plate, an anti-explosion sheet and a lower end plate, the anti-explosion sheet abuts against and is electrically connected to one side of the top cover plate, two sides of the anti-explosion sheet are respectively and fixedly provided with a first reinforcing table and a second reinforcing table, and the lower end plate is fixedly connected with the first reinforcing table. The second reinforcing table is connected with the top cover plate in a clamped mode. A central notch groove and a peripheral notch groove are formed in one side of the anti-explosion sheet; the lower end plate is welded and electrically connected to the side, away from the anti-explosion piece, of the first reinforcing table. According to the utility model, the central notch groove and the peripheral notch groove are formed in the explosion-proof sheet, and are matched with each other, so that the cap assembly can be ensured to open a valve in time when a battery is in thermal runaway, and the first reinforcing platform and the second reinforcing platform are arranged on the explosion-proof sheet, so that the assembling and matching of the explosion-proof sheet, the top cover plate and the lower end plate can be ensured; and the structural strength of the anti-explosion sheet can be enhanced, so that the normal operation of the cylindrical battery is guaranteed.

Description

Technical Field

[0001] This utility model relates to the field of cylindrical battery structure technology, and in particular to a cap assembly and a cylindrical battery. Background Technology

[0002] The cap assembly is an important part of the battery. It is usually composed of components such as an outer insulating ring, a top cover plate, an explosion-proof sheet, an inner rubber ring, and a lower end plate. By utilizing the precise cooperation of the various components within the cap assembly, it can provide the battery with good insulation and explosion-proof performance, thereby ensuring the battery's safety.

[0003] The outer insulating ring is made of plastic, and its deformability enhances the seal between the cap assembly and the battery casing. During the assembly of the cap assembly and the casing, the outer insulating ring, deformed by the casing, can compress internal components such as the explosion-proof plate.

[0004] For example, the invention patent CN119518186A discloses a large cylindrical battery with a PACKable same-side welded groove sealing structure. It features a cap ring on the outside of the explosion-proof cap, using this ring to seal and insulate the explosion-proof cap and other components within a steel casing. However, to ensure the battery's explosion-proof performance, the explosion-proof cap itself is relatively thin, resulting in weak structural strength. In other existing technologies, to ensure the explosion-proof performance, weak structures such as V-grooves are added to the explosion-proof cap, further reducing its structural strength. During assembly of the cap ring and the steel casing, the compression of the cap ring can deform the explosion-proof cap, causing the cap assembly inside the steel casing to open prematurely or not at all, posing a safety risk. Utility Model Content

[0005] In view of this, the present invention proposes a cap assembly and a cylindrical battery, which can enhance the structural strength of the explosion-proof sheet and ensure the explosion-proof performance of the cap assembly and the cylindrical battery.

[0006] The technical solution of this utility model is achieved as follows: On the one hand, this utility model provides a cap assembly, including a top cover plate, an explosion-proof sheet, and a lower end plate, wherein...

[0007] The explosion-proof sheet is abutted against and electrically connected to one side of the top cover plate. A first reinforcing platform and a second reinforcing platform are fixedly provided on both sides of the explosion-proof sheet, and the second reinforcing platform is engaged with the top cover plate. A central groove and an outer peripheral groove are provided on the side of the explosion-proof sheet away from the first reinforcing platform.

[0008] The lower end plate is welded and electrically connected to the side of the first reinforcing platform away from the explosion-proof sheet.

[0009] Based on the above technical solutions, preferably, the thickness of the explosion-proof sheet is H0, and the thickness of the second reinforcing platform is H2, wherein 50%(H0+H2)≤H0≤70%(H0+H2), and H0=0.2mm-0.4mm.

[0010] Based on the above technical solutions, preferably, the second reinforcing platform is a circular plate structure and is coaxially arranged with the explosion-proof sheet;

[0011] The width of the annulus on the side of the second reinforcing platform closest to the explosion-proof sheet is L. 41 The width of the annulus on the side furthest from the explosion-proof sheet is L. 42 Of which, 68% L 41 ≤L 42 ≤82% L 41 And L 41 =1mm-1.3mm.

[0012] More preferably, the thickness of the first reinforcing platform is H1, wherein 52%(H0+H1)≤H0≤72%(H0+H1), and (H0+H1)=0.4mm-0.6mm.

[0013] More preferably, the first reinforcing platform is located in the middle of the explosion-proof sheet;

[0014] The outer diameter of the explosion-proof sheet is L0, and the outer diameter of the first reinforcing platform on the side away from the explosion-proof sheet is L3, wherein 8%L0≤L3≤18%L0, and L0=15mm-25mm.

[0015] More preferably, the outer peripheral groove is an annular groove structure, which is formed at the outer edge of the explosion-proof sheet;

[0016] The radius of the outer peripheral groove is L2, where 12% L2 ≤ L 42 ≤22% L2.

[0017] Based on the above technical solutions, preferably, the minimum distance from the outer peripheral groove to the second reinforcing stage is L5, where L5 = 0.1mm-0.3mm.

[0018] More preferably, the minimum distance from the outer peripheral groove to the periphery of the explosion-proof sheet is L1, wherein 20%L0≤L1≤30%L0.

[0019] More preferably, the depth of the outer peripheral groove is H3, wherein 16%(H0+H2)≤(H0-H3)≤36%(H0+H2).

[0020] Secondly, this utility model provides a cylindrical battery, including the aforementioned cap assembly.

[0021] The cap assembly and cylindrical battery of this utility model have the following advantages over the prior art:

[0022] (1) By setting a central groove and an outer peripheral groove on the explosion-proof sheet, the cooperation of the two can ensure that the cap assembly opens the valve in time when the battery experiences thermal runaway. By setting a first reinforcing platform and a second reinforcing platform on the explosion-proof sheet, not only can the assembly and cooperation between the explosion-proof sheet and the top cover plate and the bottom plate be guaranteed, but the structural strength of the explosion-proof sheet can also be enhanced, thereby ensuring the normal operation of the cylindrical battery.

[0023] (2) By making the first reinforcing platform, the second reinforcing platform, and the outer peripheral groove coaxial with the explosion-proof sheet, the stability of the cap assembly can be improved and the assembly difficulty of the cap assembly can be reduced.

[0024] (3) By restricting the opening position and specifications of the first reinforcing platform, the second reinforcing platform, the central groove and the outer peripheral groove, not only can the structural strength of the explosion-proof sheet be further improved, but also the weight and material cost of the cap assembly can be reduced, and the energy density of the battery can be increased. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a cross-sectional view of an explosion-proof sheet in a cap assembly according to the present invention;

[0027] Figure 2 This is a cross-sectional view of the first reinforcing platform in a cap assembly of the present invention;

[0028] Figure 3 This is a cross-sectional view of the second reinforcing platform in a cap assembly of the present invention;

[0029] Figure 4 This is a cross-sectional view of the outer peripheral groove in a cap assembly of this utility model;

[0030] Figure 5 This is a partial cross-sectional view of a cylindrical battery according to the present invention.

[0031] The components include: 1. outer insulating ring; 2. top cover plate; 3. explosion-proof sheet; 31. first reinforcing platform; 32. second reinforcing platform; 301. center groove; 302. outer circumferential groove; 4. inner rubber ring; 5. lower end plate. Detailed Implementation

[0032] The technical solutions of this utility model will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0033] Cylindrical batteries are divided into cylindrical primary batteries and cylindrical secondary batteries. Due to their advantages such as good consistency, high energy density and good heat dissipation, they have been widely used in electronic equipment, industrial equipment, energy storage and transportation.

[0034] This utility model discloses a cylindrical battery comprising a casing, a cap assembly, a battery cell, and a current collector, wherein the cap assembly includes an outer insulating ring 1, a top cover plate 2, an explosion-proof sheet 3, an inner rubber ring 4, and a lower end plate 5. Figure 5 As shown, the positive electrode of the battery cell, the positive electrode current collector, the lower end plate 5, the explosion-proof sheet 3, and the top cover plate 2 are electrically connected in sequence. The outer edge of the lower end plate 5 and the outer edge of the explosion-proof sheet 3 are spaced apart. The inner rubber ring 4 is abutted against the gap between the explosion-proof sheet 3 and the lower end plate 5 to achieve rapid separation of the two in the event of thermal runaway of the battery. The top cover plate 2 and the explosion-proof sheet 3 are both sealed and fixed inside the outer insulating ring 1. The inner wall of the outer insulating ring 1 holds the top cover plate 2 and the explosion-proof sheet 3 together. The outer insulating ring 1 is fixed at the opening of the shell to fix the top cover plate 2 and the explosion-proof sheet 3 at the opening of the shell and to insulate the top cover plate 2 and the explosion-proof sheet 3 from the shell.

[0035] like Figure 1 As shown, a central groove 301 and an outer peripheral groove 302 are provided on one side of the explosion-proof sheet 3. The central groove 301 is located in the middle of the explosion-proof sheet 3, and the outer peripheral groove 302 is located at the outer edge of the explosion-proof sheet 3. Both groove structures are weak areas of the explosion-proof sheet 3. By utilizing the mutual supplementation of the central groove 301 and the outer peripheral groove 302, when the battery experiences problems such as thermal runaway, the gas generated inside the battery can be concentrated either at the center or at the edge of the battery, allowing the explosion-proof sheet 3 to explode in time, thereby ensuring the explosion-proof performance of the battery.

[0036] To ensure the uniformity and stability of the explosion-proof disc 3, it is preferable to set the outer peripheral groove 302 as a circular groove structure and to set the outer peripheral groove 302 coaxially with the explosion-proof disc 3.

[0037] To enhance the sealing performance between the cap assembly and the housing, the outer insulating ring 1 needs to be made of a deformable material such as plastic. When assembling the cap assembly and the housing, a certain assembly force is applied to compress and shrink the outer insulating ring 1, thereby achieving a good sealing effect.

[0038] The explosion-proof disc 3 itself has relatively weak structural strength. The opening of the central groove 301 and the outer peripheral groove 302 will further weaken the structural strength of the explosion-proof disc 3. When the cap assembly is assembled in the housing, the compression of the outer insulating ring 1 can easily cause the explosion-proof disc 3 to deform, affecting the explosion-proof disc 3 to open the valve in advance or not to open the valve, which poses a great safety hazard.

[0039] Therefore, the structure of the explosion-proof plate 3 was improved. A first reinforcing platform 31 and a second reinforcing platform 32 are fixedly installed on both sides of the explosion-proof plate 3. The first reinforcing platform 31 is located on the side of the explosion-proof plate 3 away from the central groove 301 and is also located in the middle of the explosion-proof plate 3. The second reinforcing platform 32 is located at the outer edge of the explosion-proof plate 3. Both the first reinforcing platform 31 and the second reinforcing platform 32 are protruding structures provided on the surface of the explosion-proof plate 3. They can enhance the local thickness of the explosion-proof plate 3 and disperse the pressure on the explosion-proof plate 3, thereby improving the structural strength of the explosion-proof plate 3. This effectively copes with the squeezing force exerted by the outer insulating ring 1 on the explosion-proof plate 3, ensuring the valve opening stability of the cap assembly and the explosion-proof performance of the battery.

[0040] To improve the ease of processing the explosion-proof sheet 3, the first reinforcing platform 31, and the second reinforcing platform 32, it is preferable to mold the three components as a single piece.

[0041] In addition to enhancing the structural strength of the explosion-proof plate 3, the first reinforcing platform 31 also improves the welding quality between the explosion-proof plate 3 and the lower end plate 5, such as... Figure 2 and Figure 5 As shown, the first reinforcing platform 31 is a protruding structure with a smaller area than the explosion-proof sheet 3, which makes it easier to ensure its flatness. When the side of the first reinforcing platform 31 away from the explosion-proof sheet 3 is welded to the lower end plate 5 to achieve electrical connection between the two, problems such as explosion points and incomplete welding are less likely to occur, which can effectively reduce the welding defect rate and reduce the manufacturing cost of the battery. In order to better control the reliability of the welding position between the first reinforcing platform 31 and the lower end plate 5, a protruding structure can also be provided on the side of the lower end plate 5 near the explosion-proof sheet 3, and the protruding structure can be welded and fixed to the first reinforcing platform 31.

[0042] The second reinforcing platform 32 does not only serve to strengthen the structural strength of the explosion-proof plate 3. Preferably, the second reinforcing platform 32 is a ring-shaped plate structure and is coaxially arranged with the explosion-proof plate 3. Figure 5As shown, the second reinforcing platform 32 is engaged with the top cover plate 2. During the assembly of the cap assembly, the limiting relationship formed by the second reinforcing platform 32 and the top cover plate 2 is used to ensure that the top cover plate 2 and the explosion-proof sheet 3 remain coaxial when the top cover plate 2 and the explosion-proof sheet 3 are installed in the outer insulating ring 1, without any deviation. After the cap assembly is assembled, there is no need to correct the position of the top cover plate 2 and the explosion-proof sheet 3, which greatly reduces the assembly difficulty of the cap assembly.

[0043] like Figures 2-4 As shown, the thickness of the explosion-proof sheet 3 is H0, the thickness of the first reinforcing platform 31 is H1, the thickness of the second reinforcing platform 32 is H2, the depth of the outer peripheral groove 302 is H3, the overall thickness of the explosion-proof sheet 3 and the first reinforcing platform 31 is H0+H1, the overall thickness of the explosion-proof sheet 3 and the second reinforcing platform 32 is H0+H2, and the actual thickness of the explosion-proof sheet 3 at the outer peripheral groove 302 is H0-H3.

[0044] In some embodiments, 52%(H0+H1)≤H0≤72%(H0+H1), meaning the thickness of the explosion-proof sheet 3 is 52%, 62%, or 72% of the overall thickness of the explosion-proof sheet 3 and the first reinforcing platform 31. The center groove 301 and the outer peripheral groove 302 are formed on the explosion-proof sheet 3. If H0 < 52%(H0+H1), the thickness of the explosion-proof sheet 3 is too small, and the overall thickness of the explosion-proof sheet 3 and the first reinforcing platform 31 is too large. The structure of the explosion-proof sheet 3 is relatively weak, its overall flatness is difficult to control, and it is prone to deformation, leading to unstable explosion-proof pressure of the cap assembly. The first reinforcing platform 31 is used for welding with the lower end plate 5. If H0 > 72%(H0+H1), the thickness of the explosion-proof sheet 3 is too large, and the overall thickness of the explosion-proof sheet 3 and the first reinforcing platform 31 is too small. When welding the first reinforcing platform 31 and the lower end plate 5, phenomena such as weld burn-through are likely to occur, greatly increasing the risk of battery leakage and affecting the battery's safety performance.

[0045] In some embodiments, 50%(H0+H2)≤H0≤70%(H0+H2), that is, the thickness of the explosion-proof sheet 3 is 50%, 60% or 70% of the overall thickness of the explosion-proof sheet 3 and the second reinforcing platform 32. Since the explosion-proof sheet 3 and the second reinforcing platform 32 are integrally formed by stamping, if H0 < 50% (H0 + H2), the thickness of the explosion-proof sheet 3 is too small, while the overall thickness of the explosion-proof sheet 3 and the second reinforcing platform 32 is too large. This will increase the processing difficulty of the explosion-proof sheet 3 and the second reinforcing platform 32, which will not only easily increase its processing error and reduce its processing consistency, but also increase its processing cost. The second reinforcing platform 32 plays the role of enhancing the structural strength of the explosion-proof sheet 3. If H0 > 70% (H0 + H2), the thickness of the explosion-proof sheet 3 is too large, while the overall thickness of the explosion-proof sheet 3 and the second reinforcing platform 32 is too small. The structural reinforcement effect of the second reinforcing platform 32 on the explosion-proof sheet 3 will be reduced accordingly. When the cap assembly is assembled into the housing and the groove is sealed, the cap will undergo slight deformation. At this time, the explosion-proof sheet 3 may be deformed under pressure. When the battery is producing gas normally, the explosion-proof sheet 3 will open the valve in advance, causing the battery to fail and be scrapped. Or when a large amount of gas is produced inside the battery, the explosion-proof sheet 3 cannot open the valve in time, reducing the safety performance of the battery.

[0046] In some embodiments, 16%(H0+H2)≤(H0-H3)≤36%(H0+H2), meaning the thickness of the explosion-proof piece 3 at the outer peripheral groove 302 is 16%, 26%, or 36% of the overall thickness of the explosion-proof piece 3 and the second reinforcing platform 32. If (H0-H3)<16%(H0+H2), the thickness of the explosion-proof piece 3 at the outer peripheral groove 302 is too small, and the overall thickness of the explosion-proof piece 3 and the second reinforcing platform 32 is too large. If the thickness of the explosion-proof piece 3 at the outer peripheral groove 302 is too small, the valve opening pressure of the explosion-proof piece 3 will decrease. When the battery is normally generating gas, the explosion-proof piece 3 will open prematurely, leading to battery failure and scrapping. If the overall thickness of the explosion-proof piece 3 and the second reinforcing platform 32 is too large, it will increase the processing difficulty of the explosion-proof piece 3 and the second reinforcing platform 32, not only easily increasing their processing errors and reducing their processing consistency, but also increasing their processing costs. If (H0-H3)>36%... If (H0+H2), the thickness of the explosion-proof piece 3 at the outer peripheral groove 302 is too large, and the overall thickness of the explosion-proof piece 3 and the second reinforcing platform 32 is too small. The excessive thickness of the explosion-proof piece 3 at the outer peripheral groove 302 will increase the valve opening pressure of the explosion-proof piece 3. When a large amount of gas is generated inside the battery, the explosion-proof piece 3 cannot open the valve in time, reducing the safety performance of the battery. The insufficient overall thickness of the explosion-proof piece 3 and the second reinforcing platform 32 will reduce the structural reinforcement effect of the second reinforcing platform 3 on the explosion-proof piece 3. When the cap assembly is assembled into the housing and the groove is sealed, the cap will undergo slight deformation, which will cause the explosion-proof piece 3 to open the valve prematurely or fail to open the valve in time.

[0047] In some embodiments, H0 = 0.2mm-0.4mm, (H0+H1) = 0.4mm-0.6mm, (H0+H2) = 0.4mm-0.6mm, (H0-H3) = 0.1mm-0.3mm. Specifically, (H0+H1) = (H0+H2) = 60%H0, (H0-H3) = 30%(H0+H2). In this case, the valve opening pressure of the explosion-proof plate 3 can be balanced, allowing the explosion-proof plate 3 to open the valve in time. It can also achieve rapid and precise processing of the first reinforcing platform 31, the second reinforcing platform 32, and the explosion-proof plate 3, and ensure the structural reinforcement effect of the first reinforcing platform 31 and the second reinforcing platform 32 on the explosion-proof plate 3.

[0048] like Figures 1-4 As shown, the explosion-proof plate 3 is a circular plate structure with an outer diameter of L0. Both the central groove 301 and the outer peripheral groove 302 have V-shaped cross-sections. The minimum distance from the center of the outer peripheral groove 302 to the periphery of the explosion-proof plate 3 is L1, and the radius of the center of the outer peripheral groove 302 is L2, meaning the distance between the center of the outer peripheral groove 302 and the center of the central groove 301 is L2. The first reinforcing platform 31 is a frustum-shaped structure with an outer diameter of L3 on the side away from the explosion-proof plate 3. The two sides of the second reinforcing platform 32 have different ring widths; the ring width on the side of the second reinforcing platform 32 closer to the explosion-proof plate 3 is L. 41 The width of the ring on the side of the second reinforcing platform 32 furthest from the explosion-proof plate 3 is L. 42 The minimum distance from the outer peripheral groove 302 to the second reinforcing platform 32 is L5.

[0049] In some embodiments, 20%L0≤L1≤30%L0 means that the minimum distance from the center of the groove 302 to the periphery of the explosion-proof sheet 3 is 20%, 25%, or 30% of the outer diameter of the explosion-proof sheet 3. If L1 < 20% L0, the outer peripheral groove 302 is too close to the edge of the explosion-proof sheet 3, the area of ​​the explosion-proof sheet 3 is too large, resulting in an excessively large valve opening area for the explosion-proof sheet 3, and the structural strength of the explosion-proof sheet 3 is reduced, making it prone to deformation. This causes a larger fluctuation range in the valve opening pressure of the explosion-proof sheet 3, affecting the safety performance of the battery. If L1 > 30% L0, the outer peripheral groove 302 is far from the edge of the explosion-proof sheet 3, the area of ​​the explosion-proof sheet 3 is too small, resulting in an excessively small valve opening area for the explosion-proof sheet 3. There will be a positional difference between the outer peripheral groove 302 and the exhaust hole of the lower end plate 5. When a large amount of gas is generated inside the battery, the gas cannot reach the explosion-proof sheet in a timely and rapid manner. At the same time, due to the smaller valve opening area of ​​the explosion-proof sheet 3, a large amount of gas cannot be discharged in time after the explosion-proof sheet 3 opens, resulting in a large amount of gas remaining inside the battery, affecting the safety performance of the battery.

[0050] In some embodiments, 68% L 41 ≤L 42 ≤82% L 41That is, the width of the ring on the side of the second reinforcing platform 32 away from the explosion-proof plate 3 is 68%, 75%, or 82% of the width of the ring on the side of the second reinforcing platform 32 closer to the explosion-proof plate 3, etc. If L 42 <68%L 41 If the width of the annulus on the side of the second reinforcing platform 32 furthest from the explosion-proof sheet 3 is too small, and the width of the annulus on the side of the second reinforcing platform 32 closest to the explosion-proof sheet 3 is too large, it will be difficult to control the material flow when processing the explosion-proof sheet 3 and the second reinforcing platform 32, resulting in relatively large processing errors and hindering the improvement of consistency; if L 42 >82% L 41 If the width of the ring on the side of the second reinforcing platform 32 away from the explosion-proof sheet 3 is too large, and the width of the ring on the side of the second reinforcing platform 32 close to the explosion-proof sheet 3 is too small, the molding difficulty of the second reinforcing platform 32 will increase, and the consistency of the second reinforcing platform 32 will also be difficult to guarantee.

[0051] In some embodiments, 12% L2≤L 42 ≤22% L2, meaning the width of the annulus on the side of the second reinforcing platform 32 furthest from the explosion-proof plate 3 is 12%, 17%, or 22% of the radius of the center of the outer circumferential groove 302, etc. If L 42 If L2 < 12%, the annular width of the second reinforcing platform 32 is too small, and the range of the outer peripheral groove 302 is too large. This weakens the reinforcing effect of the second reinforcing platform 32 on the explosion-proof sheet 3, reducing the structural strength of the explosion-proof sheet 3 and making it prone to deformation. This leads to unstable valve opening pressure of the explosion-proof sheet 3 and problems such as premature valve opening or failure to open the valve in time, affecting the battery's safety performance. If L2 < 12%, the annular width of the second reinforcing platform 32 is too small, and the range of the outer peripheral groove 302 is too large. 42 If L2 > 22%, the ring width of the second reinforcing platform 32 is too large, the range of the outer peripheral groove 302 is too small, the opening area of ​​the explosion-proof plate 3 becomes smaller, and when the battery produces a large amount of gas, the gas in the casing cannot be discharged quickly, timely and effectively, leading to an increase in the safety risk of the battery.

[0052] In some embodiments, 8%L0≤L3≤18%L0, that is, the outer diameter of the side of the first reinforcing platform 31 away from the explosion-proof sheet 3 is 8%, 13%, or 18% of the outer diameter of the explosion-proof sheet 3. The first reinforcing platform 31 is used to weld with the lower end plate 5. If L3<8%L0, the outer diameter of the first reinforcing platform 31 is too small, the welding area between the first reinforcing platform 31 and the lower end plate 5 is reduced, which will affect the overcurrent capacity of the battery, causing the internal temperature of the battery to rise and affecting the overall performance of the battery. At the same time, the outer diameter of the first reinforcing platform 31 is too small, which will also weaken the structural strength of the explosion-proof sheet 3, making the explosion-proof sheet 3 prone to deformation during assembly, leading to problems such as premature valve opening or failure to open the valve in time in the cap assembly, affecting the safety performance of the battery. If L3>18%L0, the outer diameter of the first reinforcing platform 31 is too large, and the flatness of the welding plane between the first reinforcing platform 31 and the lower end plate 5 is difficult to control. Problems such as incomplete welding and missing welding are prone to occur during the welding process, reducing the welding reliability between the first reinforcing platform 31 and the lower end plate 5.

[0053] In some embodiments, 15% L 42 ≤L5≤35% L 42 That is, the minimum distance from the outer peripheral groove 302 to the second reinforcing platform 32 is 15%, 25%, or 35% of the width of the annular ring on the side of the second reinforcing platform 32 away from the explosion-proof sheet 3, etc. If L5 < 15%, then... 42 If the distance between the outer peripheral groove 302 and the second reinforcing platform 32 is too small, and the width of the annulus on the side of the second reinforcing platform 32 away from the explosion-proof sheet 3 is too large, it will be difficult to control the material flow when processing the explosion-proof sheet 3 and the second reinforcing platform 32, resulting in relatively large processing errors and hindering the improvement of consistency; if L5 > 35% L 42 If the distance between the outer peripheral groove 302 and the second reinforcing platform 32 is too large, and the width of the annulus on the side of the second reinforcing platform 32 away from the explosion-proof sheet 3 is too small, the structural strength of the second reinforcing platform 32 for the explosion-proof sheet 3 will be weakened, the structural strength of the explosion-proof sheet 3 will be reduced, and it will be easy to deform, resulting in unstable valve opening pressure of the explosion-proof sheet 3, and problems such as premature valve opening or failure to open the valve in time are likely to occur, affecting the safety performance of the battery.

[0054] In some embodiments, L0 = 15mm-25mm, L1 = 3.6mm-5.4mm, L2 = 3mm-7mm, L 41 =1mm-1.3mm, L 42 =0.8mm-1mm, L5=0.1mm-0.3mm, specifically, L0=19.66mm, L1=25% L0, L 42 =75%L 41 L 42 =18% L2, L3 = 13% L0, L5 = 25% L 42At this time, it can not only balance the valve opening pressure of the explosion-proof plate 3, so that the explosion-proof plate 3 can open the valve in time, but also realize the rapid and accurate processing of the first reinforcing platform 31, the second reinforcing platform 32 and the explosion-proof plate 3, and also ensure the structural reinforcement effect of the first reinforcing platform 31 and the second reinforcing platform 32 on the explosion-proof plate 3.

[0055] The working principle of the cap assembly and cylindrical battery of this utility model is as follows:

[0056] like Figure 5 As shown, when the battery experiences thermal runaway and a large amount of gas is generated inside the casing, the gas impacts the explosion-proof sheet 3 through the through holes in the lower end plate 5 and the inner rubber ring 4. When the gas pressure reaches a specified value, it will break through the central groove 301 and the outer peripheral groove 302 on the explosion-proof sheet 3, allowing the gas to enter the pressure relief chamber at the top cover plate 2, thereby achieving the pressure relief and explosion-proof effect of the battery. At the same time, when the gas pressure inside the battery reaches the voltage cutoff pressure value, the first reinforcing platform 31 will separate from the lower end plate 5 to achieve the power cutoff effect of the battery, preventing the continued generation of heat and gas inside the battery and reducing the battery safety risk.

[0057] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A cap assembly, characterized in that: Includes a top cover plate (2), an explosion-proof sheet (3), and a lower end plate (5), wherein, The explosion-proof sheet (3) is abutted against and electrically connected to one side of the top cover plate (2). A first reinforcing platform (31) and a second reinforcing platform (32) are fixedly provided on both sides of the explosion-proof sheet (3). The second reinforcing platform (32) is snapped into the top cover plate (2). A central groove (301) and an outer peripheral groove (302) are provided on the side of the explosion-proof sheet (3) away from the first reinforcing platform (31). The lower end plate (5) is welded and electrically connected to the side of the first reinforcing platform (31) away from the explosion-proof sheet (3).

2. A cap assembly as described in claim 1, characterized in that: The thickness of the explosion-proof sheet (3) is H0, and the thickness of the second reinforcing platform (32) is H2, wherein 50% (H0+H2)≤H0≤70% (H0+H2) and H0=0.2mm-0.4mm.

3. A cap assembly as described in claim 1, characterized in that: The second reinforcing platform (32) is a circular plate structure and is coaxially arranged with the explosion-proof plate (3); The width of the annulus on the side of the second reinforcing platform (32) closest to the explosion-proof sheet (3) is L. 41 The width of the annulus on the side furthest from the explosion-proof sheet (3) is L. 42 Of which, 68% L 41 ≤L 42 ≤82%L 41 And L 41 =1mm-1.3mm.

4. A cap assembly as described in claim 2, characterized in that: The thickness of the first reinforcing platform (31) is H1, wherein 52%(H0+H1)≤H0≤72%(H0+H1) and (H0+H1)=0.4mm-0.6mm.

5. A cap assembly as described in claim 3, characterized in that: The first reinforcing platform (31) is located in the middle of the explosion-proof sheet (3); The outer diameter of the explosion-proof sheet (3) is L0, and the outer diameter of the first reinforcing platform (31) on the side away from the explosion-proof sheet (3) is L3, wherein 8%L0≤L3≤18%L0, and L0=15mm-25mm.

6. A cap assembly as described in claim 5, characterized in that: The outer peripheral groove (302) is a circular groove structure, which is opened at the outer edge of the explosion-proof sheet (3); The radius of the outer peripheral groove (302) is L2, where 12%L2≤L 42 ≤22% L2.

7. A cap assembly as described in any one of claims 1-6, characterized in that: The minimum distance from the outer peripheral groove (302) to the second reinforcing stage (32) is L5, where L5 = 0.1mm-0.3mm.

8. A cap assembly as described in claim 5 or 6, characterized in that: The minimum distance from the outer peripheral groove (302) to the periphery of the explosion-proof sheet (3) is L1, wherein 20%L0≤L1≤30%L0.

9. A cap assembly as described in claim 2 or 4, characterized in that: The depth of the outer peripheral groove (302) is H3, wherein 16%(H0+H2)≤(H0-H3)≤36%(H0+H2).

10. A cylindrical battery, characterized in that: Includes the cap assembly as described in any one of claims 1-9.

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