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 an anti-explosion sheet, an inner rubber ring and a lower end plate, and the inner rubber ring is arranged between the anti-explosion sheet and the lower end plate in an abutting manner; a sinking table is fixedly arranged on the anti-explosion sheet; an upper boss is fixedly arranged on the lower end plate, and the upper boss and the sinking table are both located in the inner rubber ring, fixed in a welded mode and electrically connected. A first air hole and a second air hole are formed in the lower end plate and the inner rubber ring respectively, and the first air hole and the second air hole correspond to the deformation groove in position. According to the utility model, the sinking platform is arranged on the explosion-proof sheet, the upper boss is arranged on the lower end plate, and the sinking platform is matched with the upper boss, so that the welding efficiency and quality of the explosion-proof sheet and the lower end plate can be obviously improved, meanwhile, the flatness of a welding area can be conveniently controlled, and the reliability and safety of the cap assembly and the battery are ensured.

Description

TECHNICAL FIELD

[0001] The utility model relates to cylindrical battery structure technical field especially, relates to a cap subassembly and cylindrical battery. BACKGROUND

[0002] The cap subassembly is an important part of the battery, which is usually composed of an outer insulating ring, a top cover plate, an explosion-proof sheet, an inner rubber ring, and a lower end plate. The precise cooperation of the components in the cap subassembly can provide good insulation and explosion-proof performance for the battery, ensuring its safety.

[0003] To ensure the explosion-proof performance of the battery, the inner rubber ring is usually designed to be located at the outer edge between the explosion-proof sheet and the lower end plate, and the center of the explosion-proof sheet and the lower end plate is welded and fixed. However, this design also brings some challenges in practice, especially during the assembly of the cap subassembly. The welding operation between the explosion-proof sheet and the lower end plate is affected by the elastic resistance of the inner rubber ring, resulting in problems such as virtual welding and explosion points between the explosion-proof sheet and the lower end plate.

[0004] As disclosed in the invention patent with publication number CN118472513A, a cylindrical secondary battery and an electrical device are provided with a connecting piece between the explosion-proof sheet and the first electrode end. Although this design can improve the welding quality of the explosion-proof sheet and the first electrode end, it increases the number of components in the cap subassembly. During the assembly of the cap subassembly, not only does it require two welding processes for the connecting piece, but also it needs to avoid displacement of the connecting piece, increasing the difficulty and complexity of the assembly of the cap subassembly and reducing the assembly efficiency of the battery. UTILITY MODEL CONTENTS

[0005] Therefore, the utility model provides a cap subassembly and a cylindrical battery, which can improve the welding efficiency and quality of the explosion-proof sheet and the lower end plate, and ensure the reliability and safety of the battery.

[0006] The technical solution of the utility model is as follows: on the one hand, the utility model provides a cap subassembly, which includes an explosion-proof sheet, an inner rubber ring, and a lower end plate. The inner rubber ring is arranged between the explosion-proof sheet and the lower end plate.

[0007] A sunken platform is fixedly arranged on the explosion-proof sheet, and a deformation slot is formed on one side of the sunken platform.

[0008] An upper protruding platform is fixedly arranged on the lower end plate. The upper protruding platform and the sunken platform are both located in the inner rubber ring, and they are welded and fixed and electrically connected. First and second air holes are formed in the lower end plate and the inner rubber ring, respectively, and the positions of the first and second air holes correspond to the position of the deformation slot.

[0009] On the basis of the above technical scheme, preferably, the outer diameter of the explosion-proof sheet is L0, the minimum distance from the center line of the second air hole to the circumferential side of the explosion-proof sheet is L1, and 18% L0≤L1≤32% L0.

[0010] On the basis of the above technical scheme, preferably, a mounting hole is arranged in the middle of the inner rubber ring, and the sunken platform and the upper boss are located in the mounting hole.

[0011] The radius difference between the inner rubber ring and the mounting hole is L2, and 15% L0≤L2≤28% L0.

[0012] Further preferably, the inner diameter of the second air hole is L3, and 20% L2≤L3≤34% L2.

[0013] Further preferably, the inner diameter of the mounting hole is greater than the outer diameter of the sunken platform and the upper boss.

[0014] Further preferably, the outer diameter of the sunken platform is smaller than the outer diameter of the upper boss, and the radius difference between the mounting hole and the sunken platform is L4, and 14% L2≤L4≤28% L2.

[0015] Further preferably, the inner diameter of the first air hole is L5, and 78% L3≤L5≤92% L3.

[0016] On the basis of the above technical scheme, preferably, the thickness of the inner rubber ring is H1, the thickness of the explosion-proof sheet is H2, and the thickness of the sunken platform is H3, and 64% (H2+H3)≤H1≤84% (H2+H3).

[0017] Further preferably, 56% H2≤H3≤76% H2, and 45% H1≤H3≤65% H1.

[0018] In a second aspect, the utility model provides a cylindrical battery comprising the cap assembly.

[0019] The cap assembly and cylindrical battery of the utility model have the following beneficial effects compared with the prior art:

[0020] (1) By setting the sunken platform on the explosion-proof sheet and the upper boss on the lower end plate, the welding efficiency and quality of the explosion-proof sheet and the lower end plate can be significantly improved by the cooperation of the sunken platform and the upper boss, and the flatness of the welding area is also convenient to control, thereby ensuring the reliability and safety of the cap assembly and the battery.

[0021] (2) By opening the second air hole in the inner rubber ring, the second air hole corresponds to the position of the first air hole and the deformation groove, which not only improves the explosion-proof performance of the battery, but also positively affects the design of the size and position of the inner rubber ring;

[0022] (3) By limiting the specifications of the inner rubber ring, the explosion-proof sheet and the sunken platform, not only can the welding quality of the explosion-proof sheet and the lower end plate 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 improved. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0024] Figure 1 It is a sectional view of a cap assembly of the present application;

[0025] Figure 2 It is a sectional view of the sunken platform in the cap assembly of the present application;

[0026] Figure 3 It is a sectional view of the second air hole in the cap assembly of the present application;

[0027] Figure 4 It is a partial sectional view of a cylindrical battery.

[0028] Among them: 1, outer insulation ring; 2, top cover plate; 3, explosion-proof sheet; 31, sunken platform; 301, deformation groove; 4, inner rubber ring; 401, second air hole; 402, assembly hole; 5, lower end plate; 51, upper boss; 501, first air hole. DETAILED DESCRIPTION

[0029] The technical solutions in the present application will be described clearly and completely in the following combined with the specific implementation of the present application. Obviously, the described implementation is only a part of the implementation of the present application, not all the implementation. Based on the implementation of the present application, all other implementations obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0030] Cylindrical batteries are divided into cylindrical primary batteries and cylindrical secondary batteries, which have been widely used in electronic devices, industrial equipment, energy storage and transportation tools, etc. due to their good consistency, high energy density and good heat dissipation performance.

[0031] Welding as an important part of the cap assembly processing technology, not only the two components are connected together, but also can make two components electrically connected. The quality of cap assembly welding plays a vital role in the safety and reliability of the battery.

[0032] The utility model discloses a cylindrical battery includes shell, cap assembly, electric core and current collector disc etc. structure, wherein, cap assembly includes outer insulating ring 1, top cover plate 2, explosion -proof sheet 3, inner rubber ring 4 and lower end plate 5, utilize the improvement of explosion -proof sheet 3, inner rubber ring 4 and lower end plate 5 structure, not only can improve the welding efficiency and quality of explosion -proof sheet 3 and lower end plate 5, also can optimize the size and position of inner rubber ring 4, guarantee the overall performance of cylindrical battery.

[0033] As Figure 4 The utility model discloses a cylindrical battery includes shell, cap assembly, electric core and current collector disc etc. structure, wherein, cap assembly includes outer insulating ring 1, top cover plate 2, explosion -proof sheet 3, inner rubber ring 4 and lower end plate 5, utilize the improvement of explosion -proof sheet 3, inner rubber ring 4 and lower end plate 5 structure, not only can improve the welding efficiency and quality of explosion -proof sheet 3 and lower end plate 5, also can optimize the size and position of inner rubber ring 4, guarantee the overall performance of cylindrical battery.

[0034] As Figure 1 And Figure 2 The utility model discloses a cylindrical battery includes shell, cap assembly, electric core and current collector disc etc. structure, wherein, cap assembly includes outer insulating ring 1, top cover plate 2, explosion -proof sheet 3, inner rubber ring 4 and lower end plate 5, utilize the improvement of explosion -proof sheet 3, inner rubber ring 4 and lower end plate 5 structure, not only can improve the welding efficiency and quality of explosion -proof sheet 3 and lower end plate 5, also can optimize the size and position of inner rubber ring 4, guarantee the overall performance of cylindrical battery.

[0035] As Figure 2 The utility model discloses a cylindrical battery includes shell, cap assembly, electric core and current collector disc etc. structure, wherein, cap assembly includes outer insulating ring 1, top cover plate 2, explosion -proof sheet 3, inner rubber ring 4 and lower end plate 5, utilize the improvement of explosion -proof sheet 3, inner rubber ring 4 and lower end plate 5 structure, not only can improve the welding efficiency and quality of explosion -proof sheet 3 and lower end plate 5, also can optimize the size and position of inner rubber ring 4, guarantee the overall performance of cylindrical battery.

[0036] As Figure 1 And Figure 3As shown, the deformation groove 301 is formed on the explosion-proof sheet 3, the first gas hole 501 is formed in the lower end plate 5, and the second gas hole 401 is formed in the inner rubber ring 4. The first gas hole 501 and the second gas hole 401 are pressure relief channels, and the positions of the first gas hole 501, the second gas hole 401 and the deformation groove 301 correspond to each other. When the battery cell appears thermal runaway, the gas generated in the shell can impact the position of the deformation groove 301 on the explosion-proof sheet 3 through the first gas hole 501 and the second gas hole 401, thereby breaking the explosion-proof sheet 3, realizing the pressure relief and explosion-proof effect of the battery.

[0037] As shown in Figure 3 , the first gas hole 501 and the second gas hole 401 are coaxially arranged, and the inner diameter of the second gas hole 401 is not less than the inner diameter of the first gas hole 501, so that the gas generated by the thermal runaway of the battery can flow smoothly from the first gas hole 501 to the second gas hole 401, avoiding the inner rubber ring 4 reducing the impact force of the gas, and ensuring the explosion-proof effect of the battery.

[0038] As shown in Figure 2 , the middle of the inner rubber ring 4 is provided with an assembly hole 402, and the sunken platform 31 and the upper platform 51 are located in the assembly hole 402, so that the sunken platform 31 and the upper platform 51 can be connected across the inner rubber ring 4.

[0039] As shown in Figure 3 , the outer diameter of the sunken platform 31 is smaller than the outer diameter of the upper platform 51, that is, the areas of the opposite surfaces of the sunken platform 31 and the upper platform 51 are large and small, which can provide a certain fault tolerance space for the alignment operation of the sunken platform 31 and the upper platform 51.

[0040] The inner diameter of the assembly hole 402 is greater than the outer diameter of the sunken platform 31 and the upper platform 51, as shown in Figures 1-3 , the outer diameter of the explosion-proof sheet 3 is L0, the minimum distance from the center line of the second gas hole 401 to the side of the explosion-proof sheet 3 is L1, the radius difference between the inner rubber ring 4 and the assembly hole 402 is L2, the inner diameter of the second gas hole 401 is L3, the radius difference between the assembly hole 402 and the sunken platform 31 is L4, and the inner diameter of the first gas hole 501 is L5.

[0041] In some embodiments, 18%L0≤L1≤32%L0, that is, the minimum distance from the center line of the second air hole 401 to the side of the explosion-proof sheet 3 can be 18%, 22%, 28%, or 32% of the outer diameter of the explosion-proof sheet 3, etc. If L1<18%L0, the second air hole 401 is too close to the edge of the inner rubber ring 4, which reduces the structural strength at the edge position of the inner rubber ring 4 and affects the overall performance of the cap assembly; if L1>32%L0, it will cause the second air hole 401 to be too close to the center of the inner rubber ring 4, resulting in the deformation groove 301 not being within the range of the second air hole 401. When the battery cell is in thermal runaway, the gas generated inside the shell cannot quickly act on the deformation groove 301, causing the gas pressure inside the battery to rise sharply in a short period of time, increasing the safety risk of the battery.

[0042] In some embodiments, L0=19.6mm, L1=4.9mm, that is, L1=25%L0.

[0043] The inner rubber ring 4 is a circular ring in plan view, and the difference between the radius of the assembly hole 402 and the ring width of the inner rubber ring 4 is in some embodiments 15%L0≤L2≤28%L0, that is, the ring width of the inner rubber ring 4 can be 15%, 22%, or 28% of the outer diameter of the explosion-proof sheet 3, etc. When the battery made of the cap assembly is subjected to a short circuit test, the gas generated inside the battery preferentially rushes to open the CID power-off mechanism on the lower end plate 5. If L2<15%L0, the ring width of the inner rubber ring 4 is too small, and there is not enough area to block the contact between the explosion-proof sheet 3 and the lower end plate 5. When the CID power-off mechanism is rushed to open, the lower end plate 5 will be offset or warped, etc., so that the lower end plate 5 and the explosion-proof sheet 3 continue to contact through the edge of the inner rubber ring 4, the battery is not completely powered off, and the battery continues to generate gas expansion, resulting in a continuous increase in the safety risk of the battery; if L2>28%L0, the ring width of the inner rubber ring 4 is too large, not only causing waste of the material of the inner rubber ring 4, but also causing the weight of the cap assembly to increase, and also reducing the energy density of the battery; wherein the CID power-off mechanism is a prior art.

[0044] In some embodiments, L0=19.6mm, L2=4.3mm, that is, L2=22%L0.

[0045] In some embodiments, 20% L2≤ L3≤ 34% L2, that is, the inner diameter of the second air hole 401 can be 20%, 25%, 30%, or 34% of the ring width of the inner rubber ring 4, etc. If L3< 20% L2, the diameter of the second air hole 401 is smaller, and the amount of gas passing through the second air hole 401 per unit time will decrease. When the battery is in thermal runaway, the efficiency of the gas generated inside the shell passing through the second air hole 401 is reduced, the gas discharge efficiency is reduced, and the battery safety risk is increased. If L3> 34% L2, the diameter of the second air hole 401 is larger. When the battery is in thermal runaway, the gas in the shell will rush through the CID power-off mechanism, and the lower end plate 5 will contact the explosion-proof sheet 3 through the second air hole 401, causing electrical connection between the two, and the battery will continue to generate gas, which will also increase the safety risk of the battery.

[0046] In some embodiments, L2= 4.3mm, L3= 1.2mm, that is, L3= 27% L2.

[0047] The sinking platform 31, the upper boss 51, and the assembly hole 402 are coaxially arranged, and the radius difference between the sinking platform 31 and the assembly hole 402, that is, the spacing width in the assembly hole 402, in some embodiments, 14% L2≤ L4≤ 28% L2, that is, the spacing width in the assembly hole 402 can be 14%, 20%, 25%, or 28% of the ring width of the inner rubber ring 4, etc. If L4< 14% L2, the spacing in the assembly hole 402 is too small, not only will cause the waste of the material of the inner rubber ring 4, leading to the increase of the weight of the cap assembly, but also will reduce the energy density of the battery; if L4> 28% L2, the ring width of the inner rubber ring 4 is smaller, and there is not enough area to block the contact between the explosion-proof sheet 3 and the lower end plate 5. When the battery is in thermal runaway, the gas in the shell will rush through the CID power-off mechanism, and the lower end plate 5 will contact the explosion-proof sheet 3 through the assembly hole 402, causing electrical connection between the two, and the battery will continue to generate gas, which will also increase the safety risk of the battery.

[0048] In some embodiments, L4= 0.9mm, L2= 4.3mm, that is, L4= 21% L2.

[0049] In some embodiments, 78%L3≤L5≤92%L3, meaning the inner diameter of the first vent 501 can be 78%, 82%, 88%, or 92% of the inner diameter of the second vent 401. When the battery experiences thermal runaway, the gas generated inside the casing first passes through the first vent 501 and then through the second vent 401. If L5 < 78%L3, the inner diameter of the first vent 501 is too small, and the amount of gas passing through the first vent 501 per unit time will decrease. When thermal runaway occurs inside the battery, the efficiency of the gas generated inside the casing passing through the first vent 501 decreases, and the gas discharge efficiency decreases, which will increase the battery safety risk. If L5 > 92%L3, the inner diameter of the second vent 401 is too small, and when the battery experiences thermal runaway, the amount of gas passing through the second vent 401 cannot quickly reach the pressure to open the explosion-proof valve 3, which will affect the battery's safety performance.

[0050] In some embodiments, L3 = 1.18 mm, L5 = 1 mm, that is, L5 = 85% L3.

[0051] like Figures 1-3 As shown, the thickness of the inner rubber ring 4 is H1, the thickness of the explosion-proof sheet 3 is H2, and the thickness of the sunken platform 31 is H3.

[0052] In some embodiments, 64%(H2+H3)≤H1≤84%(H2+H3), meaning the thickness of the inner rubber ring 4 can be 64%, 69%, 74%, 79%, or 84% of the sum of the thicknesses of the explosion-proof sheet 3 and the recessed platform 31. If H1<64%(H2+H3), the thickness of the recessed platform 31 is too large, making it difficult to process and manufacture, and also occupying a large amount of space, leading to a decrease in battery capacity. If H1>84%(H2+H3), the thickness of the explosion-proof sheet 3 and the recessed platform 31 is too thin, and the recessed platform 31 is easily welded through during the welding process between the recessed platform 31 and the upper protrusion 51, causing leakage at the welding position of the cap assembly.

[0053] In some embodiments, H1 = 0.37 mm, H2 + H3 = 0.5 mm, that is, H1 = 74% (H2 + H3).

[0054] In some embodiments, 56% H2≤H3≤76% H2, that is, the thickness of the sunken platform 31 can be 56%, 61%, 66%, 71% or 76% of the thickness of the explosion-proof sheet 3, etc. If H3<56% H2, the thickness of the sunken platform 31 is too thin, and the sunken platform 31 is easy to be welded through during the welding of the sunken platform 31 and the upper boss 51, especially when the battery is in thermal runaway, the position where the sunken platform 31 is welded through is easy to cause liquid leakage; if H3>76% H2, the thickness of the sunken platform 31 is too large, which is difficult to process and form, and is not easy to produce, at the same time, the thickness of the sunken platform 31 is too large, which occupies a large space, causing the capacity of the battery to decrease and the energy density of the battery to decrease.

[0055] In some embodiments, H2=0.3mm, H3=0.2mm, that is, H3=67% H2.

[0056] In some embodiments, 45% H1≤H3≤65% H1, that is, the thickness of the sunken platform 31 can be 45%, 50%, 55%, 60% or 65% of the thickness of the inner rubber ring 4, etc. If H3<45% H1, the thickness of the sunken platform 31 is too small, and the sunken platform 31 is easy to be welded through during the welding of the sunken platform 31 and the upper boss 51, especially when the battery is in thermal runaway, the position where the sunken platform 31 is welded through is easy to cause liquid leakage; if H3>65% H1, the thickness of the sunken platform 31 is too large, which is difficult to process and form, and is not easy to produce, at the same time, the thickness of the sunken platform 31 is too large, which occupies a large space, causing the capacity of the battery to decrease and the energy density of the battery to decrease.

[0057] In some embodiments, H1=0.37mm, H3=0.2mm, that is, H3=54% H1.

[0058] The working principle of the cap assembly and the cylindrical battery of the utility model is as follows:

[0059] As shown in the drawings, Figure 2 the cooperation of the sunken platform 31 and the upper boss 51 can significantly improve the welding efficiency and quality of the explosion-proof sheet 3 and the lower end plate 5, and facilitate the control of the flatness of the welding area, thereby ensuring the reliability and safety of the cap assembly and the battery;

[0060] As shown in the drawings, Figure 3 when the battery is in thermal runaway and gas is generated in the shell, the gas passes through the first gas hole 501 and the second gas hole 401 in turn, and impacts the position where the deformation groove 301 is opened on the explosion-proof sheet 3, and when the gas pressure reaches a specified value, the explosion-proof sheet 3 will be broken, thereby realizing the pressure relief and explosion-proof effect of the battery.

[0061] The above merely describes preferred embodiments of the present application and is not intended to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A cap assembly comprising a rupture disc (3), an inner grommet (4) and a lower end plate (5), the inner grommet (4) being arranged between the rupture disc (3) and the lower end plate (5); characterized in that a sunken platform (31) is fixedly arranged on the rupture disc (3), and a deformation groove (301) is formed on one side of the sunken platform (31); an upper platform (51) is fixedly arranged on the lower end plate (5), the upper platform (51) and the sunken platform (31) are both located in the inner grommet (4), and the upper platform (51) and the sunken platform (31) are welded and fixed and electrically connected; a first air hole (501) and a second air hole (401) are respectively formed in the lower end plate (5) and the inner grommet (4), and the first air hole (501), the second air hole (401) and the deformation groove (301) are located correspondingly.

2. A cap assembly as defined in claim 1, wherein: The outer diameter of the rupture disc (3) is L0, and the minimum distance from the center line of the second air hole (401) to the side of the rupture disc (3) is L1, wherein 18% L0≤L1≤32% L0.

3. A cap assembly as claimed in claim 2, wherein: An assembly hole (402) is formed in the middle of the inner grommet (4), and the sunken platform (31) and the upper platform (51) are both located in the assembly hole (402); The radius difference between the inner grommet (4) and the assembly hole (402) is L2, wherein 15% L0≤L2≤28% L0.

4. A cap assembly as claimed in claim 3, wherein: The inner diameter of the second air hole (401) is L3, wherein 20% L2≤L3≤34% L2.

5. A cap assembly as claimed in claim 4, wherein: The inner diameter of the assembly hole (402) is greater than the outer diameter of the sunken platform (31) and the upper platform (51).

6. A cap assembly as claimed in claim 5, wherein: The outer diameter of the sunken platform (31) is less than the outer diameter of the upper platform (51), and the radius difference between the assembly hole (402) and the sunken platform (31) is L4, wherein 14% L2≤L4≤28% L2.

7. A cap assembly as claimed in any one of claims 4 to 6, wherein: The inner diameter of the first air hole (501) is L5, wherein 78% L3≤L5≤92% L3.

8. A cap assembly as claimed in any one of claims 1 to 6 wherein: The thickness of the inner grommet (4) is H1, the thickness of the rupture disc (3) is H2, and the thickness of the sunken platform (31) is H3, wherein 64% (H2+H3)≤H1≤84% (H2+H3).

9. A cap assembly as claimed in claim 8, wherein: 56% H2≤H3≤76% H2, and 45% H1≤H3≤65% H1.

10. A cylindrical battery characterized by: The cap assembly according to any one of claims 1-9. 56% H2≤H3≤76% H2, and 45% H1≤H3≤65% H1. The cap assembly according to any one of claims 1-9.

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