Explosion-proof valve, battery cell cover plate and battery cell

Abstract

The invention relates to the technical field of batteries, and discloses an explosion-proof valve, a battery cell cover plate and a battery cell. The anti-explosion valve comprises a valve body, the valve body comprises an opening part and a transition part connected to the peripheral side of the opening part, the opening part protrudes out of the upper surface of the transition part, and the section of the opening part is in an arc shape; an annular nick surrounding the opening part is arranged between the opening part and the transition part; the annular nick comprises a first groove and a second groove communicated with the first groove, and the groove bottom of the first groove is higher than the groove bottom of the second groove in the thickness direction of the valve body. The opening part is in a protruding state relative to the transition part, so that a space can be reserved for deformation quantity possibly occurring during normal operation of the battery cell of the opening part in advance, and the opening part is prevented from generating pulling force on the annular nick due to deformation during operation of the battery cell. In addition, the section of the opening part is arranged to be in an arc shape, stress acting on the annular nick can be dispersed to the opening part in time, and the situation that the annular nick is fractured too early due to stress concentration is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and particularly to an explosion-proof valve, a cell cover plate and a cell. Background Art

[0002] Batteries are usually provided with explosion-proof valves. The main function of the explosion-proof valve is to relieve pressure and exhaust gas. When the battery undergoes thermal runaway due to reasons such as mechanical impact and abnormal internal short circuit, the high-temperature and high-pressure gas inside can be released directionally through the explosion-proof valve, thereby ensuring the safety of the battery.

[0003] Specifically, the reason why the explosion-proof valve can timely discharge the high-temperature and high-pressure gas inside the battery during thermal runaway is that the explosion-proof valve is provided with a groove-shaped notch. Since the structural strength at the notch is less than that of other regions of the explosion-proof valve, when the battery undergoes thermal runaway, the explosion-proof valve can break from the notch to release the high-temperature and high-pressure gas inside the battery. However, due to the insufficient strength at the notch currently, it is easy to cause the notch to open prematurely or break abnormally, thereby affecting the normal use of the battery. Summary of the Invention

[0004] In view of this, the present invention provides an explosion-proof valve, a cell cover plate and a cell to solve the problem that the notch of the existing explosion-proof valve has insufficient strength, resulting in the explosion-proof valve being lifted and opened or the notch breaking abnormally.

[0005] In a first aspect, the present invention provides an explosion-proof valve, comprising: a valve body, the valve body including an opening part and a transition part connected to the periphery of the opening part, the opening part protruding from the upper surface of the transition part and having an arc-shaped cross-section; a circular notch is provided between the opening part and the transition part; the circular notch includes a first groove and a second groove communicating with the first groove, and in the thickness direction of the valve body, the bottom of the first groove is higher than the bottom of the second groove.

[0006] Beneficial effects: During the normal operation of the battery cell, a certain amount of gas is also generated inside the battery cell, creating a pressure difference between the inside of the battery cell and the external environment. Therefore, before this part of the gas is discharged from the inside of the battery cell, it continuously acts on the opening part, causing the opening part to have a tendency to move or deform away from the battery cell electrode group. In this way, the notch on the explosion-proof valve may break prematurely under the pulling of the opening part. Based on this, the opening part in the present invention protrudes relative to the transition part, which can pre-reserve space for the possible deformation amount of the opening part during the normal operation of the battery cell, preventing the opening part from generating a pulling force on the annular notch due to deformation during the operation of the battery cell, thereby avoiding the situation of premature opening or abnormal fracture. In addition, by setting the cross-section of the opening part to be arc-shaped, the stress acting on the annular notch can be timely dispersed to the opening part, avoiding abnormal rupture or premature opening caused by stress concentration at the annular notch. Furthermore, the bottom of the first groove is higher than the bottom of the second groove, which means that the remaining thickness of the notch of the annular notch at the first groove is greater than the remaining thickness of the notch of the annular notch at the second groove, that is, the connection strength between the opening part and the transition part at the first groove is greater than the connection strength between the opening part and the transition part at the second groove. In this way, when the battery cell undergoes thermal runaway, the annular notch will only break from the second groove, and the annular notch will still remain connected at the first groove, so as to prevent the entire opening part from directly detaching from the battery cell under the impact of high-temperature gas flow. With such a setting, on the one hand, it can ensure that the high-pressure gas inside the battery cell can be released orderly through the fracture; on the other hand, the connection state at the first groove can maintain the structural integrity of the explosion-proof valve to a certain extent, and compared with the direct detachment of the opening part from the explosion-proof valve, it can reduce the possibility of the opening part interfering with the surrounding structure.

[0007] In an alternative embodiment, in the thickness direction of the valve body, the thickness of the opening part is B, and the value range of the thickness B of the opening part is 0.15 mm ≤ B ≤ 0.32 mm; the remaining material thickness of the bottom of the first groove is C, and the value range of the remaining material thickness C of the bottom of the first groove is 0.09 mm ≤ C ≤ 0.2 mm; the relationship between B and C satisfies: 0.05 mm ≤ (B - C) ≤ 0.12 mm; the remaining material thickness of the bottom of the second groove is D, and the relationship between C and D satisfies: D / C ≥ 0.45.

[0008] Beneficial effects: By setting the opening part according to the above parameters, it can ensure that the opening part has a certain strength. When air pressure difference is generated during the normal operation of the battery cell, the opening part can withstand a certain pressure by virtue of its own strength and will not deform easily due to being too thin. By setting the remaining material thickness C at the bottom of the first groove according to the above parameters, the opening part can be stably connected to the transition part in the open state, preventing the opening part from completely detaching from the transition part. Further, by setting the difference between B and C according to the above parameters, while ensuring that the opening part can be stably connected to the transition part through the bottom of the first groove, the stress at the annular notch can be evenly diffused to the opening part. Secondly, by setting C and D according to the above parameters, when the opening pressure of the explosion-proof valve remains unchanged, the notch thickness at the second groove of the annular notch (i.e., the remaining material thickness D at the bottom of the second groove) can be increased, thereby avoiding the explosion-proof valve from being accidentally opened during the normal operation pressure fluctuation of the battery cell due to the notch being too thin, and improving the accuracy and stability of the explosion-proof valve's operation.

[0009] In an alternative embodiment, the periphery of the opening part uniformly transitions towards the top of the opening part.

[0010] Beneficial effects: The uniform transition of the periphery of the opening part towards the top of the opening part means that the stress acting on each area of the annular notch can be gradually transmitted towards the top along the curved surface of the opening part, making the pressure borne by each part of the annular notch relatively balanced and avoiding the situation of premature rupture due to stress concentration in a certain area. In addition, the opening part is in a uniformly transitional state from the periphery to the top, which can also evenly distribute the pressure on the opening part, prevent excessive deformation caused by excessive local stress, and thus avoid premature rupture of the annular notch due to deformation and stretching.

[0011] In an alternative embodiment, the annular notch includes a straight section and arc sections located at both ends of the straight section, and the first groove is located within the straight section.

[0012] Beneficial effects: Compared with setting the first groove within the arc section, in the state of thermal runaway, the first groove located within the straight section can more effectively disperse stress, reduce the risk of stress concentration, and thus ensure that the opening part can be stably connected to the transition part, reducing the possibility of it directly detaching completely from the explosion-proof valve.

[0013] In an alternative embodiment, the designed opening pressure of the explosion-proof valve is 0.7 Mpa to 1.1 MPa; the value range of the remaining material thickness D at the bottom of the second groove is D≥0.06 mm.

[0014] Beneficial effects: An appropriate bottom thickness of the groove can ensure that the second groove can be smoothly broken and opened when the designed opening pressure is reached, and at the same time, it will not be opened in advance due to the too thin thickness during the normal operating pressure fluctuation. If the value of D is too small, during the normal operation of the battery cell, a slight pressure change may cause the second groove to rupture, making the explosion-proof valve lose its due protection function. While D≥0.06mm can ensure that the second groove remains intact under normal working conditions and can be opened in time under extreme pressure, and cooperate with the first groove to maintain the connection between the opening part and the transition part after opening, ensuring the orderly discharge of the high-pressure gas inside the battery cell and effectively improving the safety protection performance of the explosion-proof valve under complex working conditions.

[0015] In an alternative embodiment, the opening part, the annular notch and the transition part are integrally formed.

[0016] Beneficial effects: Using the integral forming process to prepare the opening part, the annular notch and the transition part can not only reduce the time cost in the production process, but also improve the overall structural strength of the explosion-proof valve.

[0017] In an alternative embodiment, the explosion-proof valve further includes a skirt surrounding the outer periphery of the transition part, and the thickness of the skirt is greater than the thickness of the transition part.

[0018] Beneficial effects: By providing a skirt on the outer periphery of the transition part and making the thickness of the skirt greater than the thickness of the transition part, on the one hand, it can improve the self-structural strength of the explosion-proof valve; on the other hand, when the explosion-proof valve is installed at a preset position on the housing or the battery cell cover plate, the thicker skirt can increase the connection area between the explosion-proof valve and the housing or the battery cell cover plate.

[0019] In an alternative embodiment, the upper surface of the skirt is higher than the upper surface of the transition part, and the thickness of the skirt is A, and the value range of A is 0.4mm≤A≤0.6mm.

[0020] Beneficial effects: The skirt of the present invention is set according to the above parameters. The skirt will neither be unable to withstand possible external mechanical impacts due to being too thin, nor increase too much unnecessary weight and cost due to being too thick.

[0021] In a second aspect, the present invention further provides a battery cell cover plate, including:

[0022] A cover plate body provided with a mounting hole;

[0023] The above-mentioned explosion-proof valve is arranged in the mounting hole.

[0024] Beneficial effects: This battery cell cover plate, including the above-mentioned explosion-proof valve, has all the beneficial technical effects of this battery cell cover plate, which will not be elaborated here.

[0025] In a third aspect, the present invention further provides a battery cell, including:

[0026] A housing with an opening on one side;

[0027] The above-mentioned battery cell cover plate covers and seals the opening.

[0028] Advantageous effects: This battery cell, including the above-mentioned battery cell cover plate, has all the beneficial technical effects of this battery cell, which will not be elaborated here. Brief Description of the Drawings

[0029] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0030] Figure 1 It is a schematic structural diagram of an explosion-proof valve according to an embodiment of the present invention;

[0031] Figure 2 For Figure 1 It is a cross-sectional schematic diagram of the explosion-proof valve shown;

[0032] Figure 3 For Figure 1 It is a partial enlarged schematic diagram of M in;

[0033] Figure 4 It is a schematic structural diagram of a battery cell according to an embodiment of the present invention.

[0034] Description of the reference numerals:

[0035] 1. Valve body; 101. Opening part; 102. Transition part; 103. Annular groove; 1031. First groove; 1032. Second groove; 1033. Straight section; 1034. Arc section; 2. Skirt; 3. Battery cell cover plate; 4. Housing; 401. Opening. Specific Embodiments

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0037] The following will describe the embodiments of the present invention in conjunction with Figures 1 to 4 , describing the embodiments of the present invention.

[0038] According to an embodiment of the present invention, on the one hand, as Figures 1 to 3 shown, an explosion-proof valve is provided, including: a valve body 1, the valve body 1 includes an opening part 101 and a transition part 102 connected to the periphery of the opening part 101, the opening part 101 protrudes from the upper surface of the transition part 102 and its cross-sectional shape is arc-shaped; an annular notch 103 is provided between the opening part 101 and the transition part 102; the annular notch 103 includes a first groove 1031 and a second groove 1032 communicating with the first groove 1031, in the thickness direction of the valve body 1, the bottom of the first groove 1031 is higher than the bottom of the second groove 1032.

[0039] During the normal operation of the battery cell, a certain amount of gas will also be generated inside the battery cell, forming a pressure difference between the inside of the battery cell and the external environment. Therefore, before this part of the gas is discharged from the inside of the battery cell, it will continuously act on the opening part 101, so that the opening part 101 has a tendency to move or deform away from the battery cell electrode group. In this way, the notch on the explosion-proof valve may break prematurely under the pulling of the opening part 101. Based on this, the opening part 101 in this embodiment protrudes compared with the transition part 102, which can pre-reserve space for the possible deformation amount of the opening part 101 during the normal operation of the battery cell, preventing the opening part 101 from generating a pulling force on the annular notch 103 due to deformation during the operation of the battery cell, thereby avoiding the situation of premature opening or abnormal fracture. In addition, setting the cross-section of the opening part 101 as arc-shaped can timely disperse the stress acting on the annular notch 103 to the opening part 101, avoiding the abnormal rupture or premature opening of the annular notch 103 due to stress concentration. Moreover, the bottom of the first groove 1031 is higher than the bottom of the second groove 1032, which means that the remaining thickness of the notch of the annular notch 103 at the first groove 1031 is greater than the remaining thickness of the notch of the annular notch 103 at the second groove 1032, that is to say, the connection strength between the opening part 101 and the transition part 102 at the first groove 1031 is greater than the connection strength between the opening part 101 and the transition part 102 at the second groove 1032. In this way, when the battery cell undergoes thermal runaway, the annular notch 103 will only break from the second groove 1032, and the annular notch 103 will still remain connected at the first groove 1031, so as to avoid the entire opening part 101 from directly detaching from the battery cell under the impact of high-temperature gas flow. With such a setting, on the one hand, it can ensure that the high-pressure gas inside the battery cell can be released orderly through the fracture; on the other hand, the connection state at the first groove 1031 can maintain the structural integrity of the explosion-proof valve to a certain extent, and compared with the opening part 101 directly detaching from the explosion-proof valve, it can reduce the possibility of the opening part 101 interfering with the surrounding structures.

[0040] It can be understood that the air pressure difference formed between the inside and the outside environment of the battery cell in the thermal runaway state is much greater than that formed between the inside and the outside environment of the battery cell in the normal operation state. Therefore, even though in this embodiment, the structural stability of the annular notch 103 can be improved to a certain extent by changing the shape of the opening part 101, it will not affect the normal opening of the subsequent explosion-proof valve under the opening pressure (in the thermal runaway state), ensuring the use safety of the battery cell.

[0041] In addition, usually, the explosion-proof valve is arranged on the battery cell cover plate 3 or the housing 4 through a welding process. However, welding stress will be generated during the welding process. To avoid the welding stress directly acting on the annular notch 103, in this embodiment, a transition part 102 with a certain width is arranged around the circumference of the annular notch 103, which can block the continuous transmission of the welding stress to a certain extent and reduce the influence of the welding stress on the annular notch 103.

[0042] According to an embodiment of the present invention, as Figure 2 shown, in the thickness direction of the valve body 1, the thickness of the opening part 101 is B, and the value range of the thickness B of the opening part 101 is 0.15 mm ≤ B ≤ 0.32 mm; the remaining material thickness at the bottom of the first groove 1031 is C, and the value range of the remaining material thickness C at the bottom of the first groove 1031 is 0.09 mm ≤ C ≤ 0.2 mm; the relationship between B and C satisfies: 0.05 mm ≤ (B - C) ≤ 0.12 mm; the remaining material thickness at the bottom of the second groove 1032 is D, and the relationship between C and D satisfies: D / C ≥ 0.45. By setting the opening part 101 according to the above parameters in this embodiment, it can ensure that the opening part 101 has a certain strength. When the air pressure difference is generated during the normal operation of the battery cell, the opening part 101 can withstand a certain pressure by virtue of its own strength and will not be easily deformed due to being too thin. And by setting the remaining material thickness C at the bottom of the first groove 1031 according to the above parameters, the opening part 101 can be stably connected to the transition part 102 in the open state, avoiding the complete separation of the opening part 101 from the transition part 102. Further, by setting the difference between B and C according to the above parameters, it can ensure that while the opening part 101 can be stably connected to the transition part 102 through the bottom of the first groove 1031, the stress at the annular notch 103 can be evenly diffused to the opening part 101. Secondly, by setting C and D according to the above parameters, it can increase the notch thickness at the second groove 1032 of the annular notch 103 (i.e., the remaining material thickness D at the bottom of the second groove 1032) without changing the opening pressure of the explosion-proof valve, thereby avoiding the mis-opening of the explosion-proof valve during the pressure fluctuation of the battery cell in normal operation due to the too thin notch, and improving the accuracy and stability of the explosion-proof valve.

[0043] According to an embodiment of the present invention, as Figure 1 and Figure 2As shown, the periphery of the opening part 101 uniformly transitions to the top of the opening part 101. The uniform transition of the periphery of the opening part 101 to the top of the opening part 101 means that the stress acting on each area of the annular notch 103 can be gradually transmitted to the top along the curved surface of the opening part 101, making the pressure borne by each part of the annular notch 103 relatively balanced, and avoiding the situation of stress concentration in a certain area leading to premature rupture. In addition, the opening part 101 being in a uniformly transitional state from the periphery to the top can also evenly distribute the pressure on the opening part 101, prevent excessive local stress from causing excessive deformation, and further avoid premature rupture of the annular notch 103 due to deformation stretching.

[0044] According to an embodiment of the present invention, as Figure 1 and Figure 3 shown, the annular notch 103 includes a straight section 1033 and arc sections 1034 located at both ends of the straight section 1033, and the first groove 1031 is located within the straight section 1033. Compared with setting the first groove 1031 within the arc section 1034, in a thermal runaway state, the first groove 1031 located within the straight section 1033 can more effectively disperse stress, reduce the risk of stress concentration, and thus ensure that the opening part 101 can be stably connected to the transition part 102, reducing the possibility of it directly detaching completely from the explosion-proof valve.

[0045] In one embodiment, the extending direction of the straight section 1033 is consistent with the length direction of the valve body.

[0046] According to an embodiment of the present invention, the designed opening pressure of the explosion-proof valve is 0.7 Mpa to 1.1 MPa; the value range of the remaining material thickness D at the bottom of the second groove 1032 is D ≥ 0.06 mm. An appropriate bottom thickness can ensure that when the designed opening pressure is reached, the second groove 1032 can be smoothly fractured and opened, and at the same time, it will not be prematurely opened due to too thin a thickness during normal operating pressure fluctuations. If the value of D is too small, during the normal operation of the battery cell, a slight pressure change may cause the second groove 1032 to rupture, making the explosion-proof valve lose its due protection function. And D ≥ 0.06 mm can ensure that the second groove 1032 remains intact under normal working conditions and can be opened in time under extreme pressure, cooperating with the first groove 1031 to maintain the connection between the opening part 101 and the transition part 102 after opening, ensuring the orderly discharge of high-pressure gas inside the battery cell and effectively improving the safety protection performance of the explosion-proof valve under complex working conditions.

[0047] According to an embodiment of the present invention, the opening part 101, the annular notch 103, and the transition part 102 are integrally formed. Using an integral forming process to prepare the opening part 101, the annular notch 103, and the transition part 102 can not only reduce the time cost during the production process but also improve the overall structural strength of the explosion-proof valve.

[0048] According to an embodiment of the present invention, as Figure 1 shown, the explosion-proof valve further includes a skirt 2 surrounding the outer periphery of the transition portion 102, and the thickness of the skirt 2 is greater than the thickness of the transition portion 102. In this embodiment, by providing the skirt 2 on the outer periphery of the transition portion 102 and making the thickness of the skirt 2 greater than the thickness of the transition portion 102, on the one hand, the self-structural strength of the explosion-proof valve can be improved; on the other hand, when the explosion-proof valve is installed at a preset position on the housing 4 or the battery cell cover plate 3, the thicker skirt 2 can increase the connection area between the explosion-proof valve and the housing 4 or the battery cell cover plate 3.

[0049] According to an embodiment of the present invention, as Figure 1 shown, the upper surface of the skirt 2 is higher than the upper surface of the transition portion 102, and the thickness of the skirt 2 is A, and the value range of A is 0.4 mm ≤ A ≤ 0.6 mm. In this embodiment, the skirt 2 is set according to the above parameters. The skirt 2 will neither be unable to withstand possible external mechanical impacts due to being too thin nor increase too much unnecessary weight and cost due to being too thick.

[0050] According to an embodiment of the present invention, on the other hand, as Figure 4 shown, a battery cell cover plate 3 is further provided, including: a cover plate body and the above-mentioned explosion-proof valve. Specifically, the cover plate body is provided with a mounting hole; the above-mentioned explosion-proof valve is arranged in the mounting hole. This battery cell cover plate 3, including the explosion-proof valve as described above, has all the beneficial technical effects of this battery cell cover plate 3, which will not be elaborated here.

[0051] According to an embodiment of the present invention, on the other hand, as Figure 4 shown, a battery cell is further provided, including: a housing 4 and a battery cell cover plate 3. Specifically, an opening 401 is provided on one side of the housing 4; the above-mentioned battery cell cover plate 3 covers and seals the opening 401. This battery cell, including the battery cell cover plate 3 as described above, has all the beneficial technical effects of this battery cell, which will not be elaborated here.

[0052] Next, the technical effects of the technical solutions of the embodiments of the present invention will be described in conjunction with specific embodiments and comparative examples.

[0053] Table 1: The designed opening pressure of the explosion-proof valve is 0.9 ± 0.2 Mpa, and the design requirement is D ≥ 0.06 mm.

[0054]

[0055]

[0056] Table 2: The designed opening pressure of the explosion-proof valve is 0.9 ± 0.2 Mpa, and the design requirement is D ≥ 0.09 mm.

[0057]

[0058] It can be seen that if the value of (B - C) is too small, the connection between the first groove 1031 and the opening part 101 is basically a plane, and the radian of the whole opening part 101 is uneven; if the value of (B - C) is too large, the bottom thickness of the first groove 1031 is too small, and there is a risk that the opening part 101 will fall off and fly out after the explosion-proof valve is opened. When the value of (B - C) satisfies 0.05 ≤ h ≤ 0.12 and D / C ≥ 0.45, it can ensure that the convex surface of the opening part 101 has a uniform transition, the convex surface is smooth and natural, and has good stability, and the bottom thickness of the second groove 1032 is relatively high, meeting the requirement of the design annular groove 103 for the residual thickness of the groove at the second groove 1032.

[0059] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations fall within the scope defined by the appended claims.

Claims

1. An explosion-proof valve, characterized in that: include: A valve body, the valve body comprising an opening portion and a transition portion connected to the peripheral side of the opening portion, the opening portion protruding from the upper surface of the transition portion and having an arc-shaped cross-section; an annular notch surrounding the opening portion is provided between the opening portion and the transition portion; the annular notch comprises a first groove and a second groove connected to the first groove, and in the thickness direction of the valve body, the bottom of the first groove is higher than the bottom of the second groove.

2. The explosion-proof valve according to claim 1, characterized in that: In the thickness direction of the valve body, the thickness of the opening part is B, and the value range of the thickness B of the opening part is 0.15mm≤B≤0.32mm; the thickness of the residual material at the bottom of the first groove is C, and the value range of the thickness C of the residual material at the bottom of the first groove is 0.09mm≤C≤0.2mm; the relationship between B and C satisfies: 0.05mm≤(BC)≤0.12mm; the thickness of the residual material at the bottom of the second groove is D, and the relationship between C and D satisfies: D / C≥0.

45.

3. The explosion-proof valve according to claim 2, characterized in that: The periphery of the opening portion transitions evenly to the top of the opening portion.

4. The explosion-proof valve according to claim 1, characterized in that: The annular notch includes a straight section and arcuate sections located at two ends of the straight section, and the first groove is located in the straight section.

5. The explosion-proof valve according to claim 1, characterized in that: The designed opening pressure of the explosion-proof valve is 0.7 MPa to 1.1 MPa; the value range of the residual material thickness D at the bottom of the second groove is D≥0.06 mm.

6. The explosion-proof valve according to any one of claims 1 to 5, characterized in that: The opening portion, the annular notch and the transition portion are integrally formed.

7. The explosion-proof valve according to any one of claims 1 to 5, characterized in that: The explosion-proof valve further includes a skirt surrounding the outer periphery of the transition portion, wherein the thickness of the skirt is greater than the thickness of the transition portion.

8. The explosion-proof valve according to claim 7, characterized in that: The upper surface of the skirt is higher than the upper surface of the transition portion, the thickness of the skirt is A, and the value range of A is 0.4mm≤A≤0.6mm.

9. A battery cell cover, characterized in that: include: The cover body is provided with a mounting hole; The explosion-proof valve according to any one of claims 1 to 8 is arranged in the mounting hole.

10. A battery cell, characterized in that: include: A shell having an opening on one side; The cell cover plate of claim 9 covers and seals the opening.

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