Explosion-proof valve, cell cover and cell

Abstract

This invention relates to the field of battery technology and discloses an explosion-proof valve, a cell cover plate, and a cell. The explosion-proof valve includes: a valve body, comprising an opening portion and a transition portion connected to the periphery of the opening portion; an annular groove surrounding the opening portion is provided between the opening portion and the transition portion; a skirt, connected to the transition portion and surrounding its periphery; along the width direction of the explosion-proof valve, the total width of the explosion-proof valve is A, where A ranges from 8mm to 40mm; the width of the skirt is B, where B ranges from 0.7mm to 3mm; the width of the transition portion is C, where C ranges from 0.5mm to 3mm; the relationship between A, B, and C satisfies: 0.05 ≤ B / A ≤ 0.12, 0.04 ≤ C / (A-2B) ≤ 0.15. By setting the total width, skirt width, and transition portion width of the explosion-proof valve according to the above parameters, this invention can increase the groove thickness of the annular groove under the same opening pressure, thereby improving the overall structural strength of the explosion-proof valve.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to an explosion-proof valve, a cell cover, and a cell. Background Technology

[0002] Batteries are typically equipped with explosion-proof valves. The main function of the explosion-proof valve is to release pressure and vent gas. When the battery experiences thermal runaway due to mechanical impact, abnormal internal short circuit, or other reasons, the high-temperature and high-pressure gas inside can be released in a directional manner through the explosion-proof valve, thereby ensuring the safety of the battery.

[0003] Specifically, the explosion-proof valve can promptly release the high-temperature, high-pressure gas inside the battery during thermal runaway because it has groove-like grooves. Since the structural strength at the grooved area is lower than that of other areas of the explosion-proof valve, it can break at these grooves to release the high-temperature, high-pressure gas when thermal runaway occurs. However, currently, the strength at these grooved areas is insufficient, which can lead to premature opening or abnormal breakage, thus 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 existing explosion-proof valves have insufficient strength at the grooves, causing the valve to lift and open or to break abnormally at the grooves.

[0005] In a first aspect, the present invention provides an explosion-proof valve, comprising:

[0006] The valve body includes an opening portion and a transition portion connected to the periphery of the opening portion; an annular groove is provided between the opening portion and the transition portion surrounding the opening portion;

[0007] A skirt hem, which connects to the transition portion and surrounds the periphery of the transition portion;

[0008] Along the width direction of the explosion-proof valve, the total width of the explosion-proof valve is A, and the value of A is 8mm≤A≤40mm; the width of the skirt is B, and the value of B is 0.7mm≤B≤3mm; the width of the transition part is C, and the value of C is 0.5mm≤C≤3mm; the relationship between A, B and C satisfies: 0.05≤B / A≤0.12, 0.04≤C / (A-2B)≤0.15.

[0009] Beneficial Effects: By setting parameters A, B, and C as described above, this invention maximizes the effective opening area (area of ​​the opening portion) of an explosion-proof valve with the same total area under the same opening pressure. This increases the residual thickness of the annular groove, improves the overall structural strength of the explosion-proof valve, and reduces the risk of abnormal cracking or premature opening. If the values ​​of B and C are too large, the effective opening area of ​​the explosion-proof valve with the same total area will decrease, leading to an increase in opening pressure. To maintain the opening pressure within the design range, the only solution is to reduce the residual thickness of the annular groove. However, this inevitably reduces the deformation resistance of the annular groove, increasing the risk of premature opening. Conversely, if the values ​​of B and C are too small, deformation of the annular groove due to welding heat may occur during welding of the explosion-proof valve to the cover body of the battery cell cover. This results in an overall decrease in the opening pressure of the explosion-proof valve, thereby increasing the risk of abnormal opening.

[0010] In one alternative embodiment, the annular groove includes a first groove and a second groove communicating with the first groove, wherein the bottom of the first groove is higher than the bottom of the second groove in the thickness direction of the valve body.

[0011] Beneficial effects: In this invention, the bottom of the first groove is higher than the bottom of the second groove. This means that the residual thickness of the annular groove at the first groove is greater than that at the second groove. In other words, the connection strength between the opening part and the transition part at the first groove is greater than that between the opening part and the transition part at the second groove. Therefore, in the event of thermal runaway in the battery cell, the annular groove will only break at the second groove, while the annular groove will remain connected at the first groove. This prevents the entire opening part from detaching directly from the battery cell under the pressure of the high-temperature gas flow. This design ensures, on the one hand, that the high-pressure gas inside the battery cell can be released in an orderly manner through the breakage point; on the other hand, the connection at the first groove can maintain the structural integrity of the explosion-proof valve to a certain extent, reducing the possibility of the opening part interfering with the surrounding structure compared to the opening part detaching directly from the explosion-proof valve.

[0012] In one alternative embodiment, the annular groove includes a straight section and arcuate sections at both ends of the straight section, with the first groove located within the straight section.

[0013] Beneficial effects: Compared with setting the first groove in the arc section, the first groove located in the straight section can more effectively disperse stress and reduce the risk of stress concentration under thermal runaway conditions. This ensures that the opening part can be stably connected to the transition part, reducing the possibility of it completely detaching from the explosion-proof valve.

[0014] In one optional embodiment, the projected area of ​​the opening portion on the horizontal plane is S, and the value of S ranges from 80 mm. 2 ≤S≤1000mm2 The length of the first groove is L, and the value of L is in the range of 5mm ≤ L ≤ 15mm; the cross-sectional area of ​​the residual material at the bottom of the first groove along its length is S1; the relationship between S1, L, and S satisfies: 2.7 × 10⁻⁶ -4 mm≤(L×S1) / S≤8.0×10 -4 mm.

[0015] Beneficial Effects: By setting the size of the annular groove at the first groove according to the above parameters, this invention can significantly increase the residual thickness of the annular groove at the second groove under the same opening pressure, thereby improving the overall structural strength of the explosion-proof valve and reducing the risk of abnormal cracking or premature opening of the explosion-proof valve. Specifically, the explosion-proof valve is designed with a first groove and a second groove. The opening method is that after the second groove breaks, the opening part of the explosion-proof valve flips over, allowing the high-temperature and high-pressure gas flow to be discharged smoothly. After flipping, the residual material at the bottom of the first groove of the explosion-proof valve connects to the cover body of the battery cell cover, thereby allowing the explosion-proof valve to open according to the designed path. Then, by reasonably setting the length of the first groove and the cross-sectional area S1 of the residual material at the bottom of the first groove according to the above parameters, the opening pressure of explosion-proof valves with the same structure and the same effective opening area can be reduced to the minimum. In this way, if it is desired to keep the opening pressure of the explosion-proof valve within the original design range, the residual material thickness at the second groove of the explosion-proof valve can be increased, thereby improving the resistance of the second groove of the explosion-proof valve to external tensile deformation.

[0016] In one optional embodiment, along the thickness direction of the valve body, the thickness of the residual material at the bottom of the first groove is H, and the value range of H is: 0.09mm≤H≤0.23mm; along the width direction of the first groove, the width of the residual material at the bottom of the first groove is W, and the value range of W is: 0.05mm≤W≤0.12mm; the relationship between W, H and S1 satisfies: S1=W×H.

[0017] Beneficial effect: By setting H and W according to the above parameters, it can be ensured that the residual thickness of the annular groove at the second groove is greater under the same opening pressure, so that the explosion-proof valve will not open prematurely due to insufficient strength at the groove before reaching the set opening pressure.

[0018] In one optional embodiment, in the thickness direction of the valve body, the thickness of the opening portion is D, and the value range of the thickness D of the opening portion is 0.15mm≤D≤0.32mm; the relationship between D and H satisfies: 0.05mm≤(DH)≤0.12mm; the thickness of the residual material at the bottom of the second groove is E, and the relationship between E and H satisfies: E / H≥0.45.

[0019] Beneficial Effects: By setting the opening part according to the above parameters, this invention ensures that the opening part has a certain strength. When the pressure difference is generated during normal operation of the battery cell, the opening part can withstand a certain pressure due to its own strength, and will not easily deform due to being too thin. Furthermore, setting the thickness H of the residual material at the bottom of the first groove according to the above parameters allows the opening part to be stably connected to the transition part in the open state, preventing the opening part from completely separating from the transition part. Further, setting the difference between D and H according to the above parameters ensures that the opening part can be stably connected to the transition part through the bottom of the first groove, while also allowing the stress at the annular groove to be evenly diffused to the opening part. Secondly, setting H and E according to the above parameters increases the groove thickness of the annular groove at the second groove (i.e., the residual material thickness E at the bottom of the second groove) while keeping the explosion-proof valve opening pressure constant. This prevents the explosion-proof valve from opening erroneously during normal operation pressure fluctuations due to excessively thin grooves, improving the accuracy and stability of the explosion-proof valve's operation.

[0020] In one alternative embodiment, the opening portion protrudes from the upper surface of the transition portion and has an arc-shaped cross-section.

[0021] Beneficial Effects: During normal operation of the battery cell, a certain amount of gas is generated inside the cell, creating a pressure difference between the cell's interior and the external environment. Therefore, before this gas is expelled from the cell, it continues to act on the opening portion, causing it to tend to move or deform away from the cell's electrode assembly. This can cause the grooves on the explosion-proof valve to break prematurely under the tension of the opening portion. Based on this, the opening portion in this invention protrudes compared to the transition portion, pre-reserving space for potential deformation during normal cell operation. This prevents the opening portion from exerting a pulling force on the annular grooves due to deformation during cell operation, thus avoiding lifting or abnormal breakage. Furthermore, designing the opening portion's cross-section as an arc can promptly and evenly distribute the stress acting on the annular grooves to the opening portion, preventing abnormal breakage or premature opening due to stress concentration at the annular grooves.

[0022] In one alternative embodiment, the opening portion transitions evenly from its periphery to its top.

[0023] Beneficial effects: The uniform transition from the periphery to the top of the opening means that the stress acting on each area of ​​the annular notch can be gradually transmitted along the curved surface of the opening towards the top, resulting in relatively balanced pressure across the annular notch and preventing stress concentration in any area that could lead to premature breakage. Furthermore, the uniform transition from the periphery to the top of the opening also ensures even pressure distribution, preventing excessive localized stress that could cause excessive deformation and thus avoiding premature breakage due to stretching of the annular notch.

[0024] Secondly, the present invention also provides a battery cell cover plate, comprising:

[0025] The cover plate body is provided with mounting holes;

[0026] The aforementioned explosion-proof valve is installed inside the mounting hole.

[0027] Beneficial effects: This battery cell cover, including the explosion-proof valve mentioned above, has all the beneficial technical effects of the battery cell cover, which will not be repeated here.

[0028] Thirdly, the present invention also provides a battery cell, comprising:

[0029] The casing has an opening on one side;

[0030] The aforementioned cell cover plate covers and seals the opening.

[0031] Beneficial effects: This battery cell, including the battery cell cover as described above, has all the beneficial technical effects of the battery cell, which will not be repeated here. Attached Figure Description

[0032] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of an explosion-proof valve according to an embodiment of the present invention;

[0034] Figure 2 for Figure 1 A magnified view of part M in the diagram;

[0035] Figure 3 for Figure 1 A cross-sectional schematic diagram of the explosion-proof valve shown;

[0036] Figure 4 A magnified view of N in the diagram;

[0037] Figure 5 for Figure 1 A top view of the explosion-proof valve shown.

[0038] Figure 6 This is a schematic diagram of the structure of a battery cell according to an embodiment of the present invention.

[0039] Explanation of reference numerals in the attached figures:

[0040] 1. Valve body; 101. Opening part; 102. Transition part; 103. Annular groove; 1031. First groove; 1032. Second groove; 1033. Straight section; 1034. Arc-shaped section; 2. Skirt; 3. Battery cell cover; 4. Housing; 401. Opening. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] The following is combined Figures 1 to 6 The following describes embodiments of the present invention.

[0043] According to an embodiment of the present invention, in one aspect, such as Figure 1 and Figure 4 As shown, an explosion-proof valve is provided, including: valve body 1 and skirt 2.

[0044] Specifically, the valve body 1 includes an opening portion 101 and a transition portion 102 connected to the periphery of the opening portion 101; an annular groove 103 is provided between the opening portion 101 and the transition portion 102, surrounding the opening portion 101; the skirt 2 is connected to the transition portion 102 and surrounds the periphery of the transition portion 102.

[0045] Along the width direction of the explosion-proof valve, the total width of the explosion-proof valve is A, and the value of A is 8mm≤A≤40mm; the width of the skirt 2 is B, and the value of B is 0.7mm≤B≤3mm; the width of the transition part 102 is C, and the value of C is 0.5mm≤C≤3mm; the relationship between A, B and C satisfies: 0.05≤B / A≤0.12, 0.04≤C / (A-2B)≤0.15.

[0046] In this embodiment, by setting parameters A, B, and C as described above, the effective opening area (area of ​​the opening part 101) of the explosion-proof valve with the same total area can be maximized under the same opening pressure. This increases the residual thickness of the annular notch 103, improves the overall structural strength of the explosion-proof valve, and reduces the risk of abnormal cracking or premature opening. If the values ​​of B and C are too large, the effective opening area of ​​the explosion-proof valve with the same total area will decrease, leading to an increase in opening pressure. To keep the opening pressure within the design range, it can only be achieved by reducing the residual thickness of the annular notch 103. However, this will inevitably reduce the deformation resistance of the annular notch 103 of the explosion-proof valve, increasing the risk of premature valve opening. On the other hand, if the values ​​of B and C are too small, the annular notch 103 of the explosion-proof valve will deform due to welding heat when welding the explosion-proof valve to the cover body of the battery cell cover plate 3, resulting in an overall decrease in the opening pressure of the explosion-proof valve, thereby increasing the risk of abnormal valve opening.

[0047] Furthermore, explosion-proof valves are typically installed on the cell cover plate 3 or housing 4 via welding. However, welding stress is generated during the welding process. To prevent the welding stress from acting directly on the annular notch 103, this embodiment provides a transition portion 102 of a certain width around the annular notch 103. This can, to a certain extent, block the continuous transmission of welding stress and reduce the impact of welding stress on the annular notch 103.

[0048] It should be noted that, in this embodiment, the width B of the skirt 2 refers to the width of any area around the transition portion 102; similarly, the width C of the transition portion 102 refers to the width of any area around the annular notch 103.

[0049] According to one embodiment of the present invention, the opening portion 101, the annular groove 103, and the transition portion 102 are integrally formed. Using an integral forming process to manufacture the opening portion 101, the annular groove 103, and the transition portion 102 not only reduces time costs in the production process but also improves the overall structural strength of the explosion-proof valve.

[0050] According to one embodiment of the present invention, such as Figures 1 to 3 As shown, the explosion-proof valve also includes a skirt 2 surrounding the outer periphery of the transition portion 102. 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 greater than the thickness of the transition portion 102. In this embodiment, by providing a skirt 2 around 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, the structural strength of the explosion-proof valve itself can be improved. On the other hand, when the explosion-proof valve is installed in a preset position on the housing 4 or the battery cell cover 3, the thicker skirt 2 can increase the connection area between the explosion-proof valve and the housing 4 or the battery cell cover 3.

[0051] According to one embodiment of the present invention, such as Figures 1 to 5 As shown, the annular groove 103 includes a first groove 1031 and a second groove 1032 connected to 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. In this embodiment, the bottom of the first groove 1031 is higher than the bottom of the second groove 1032, which means that the residual thickness of the annular groove 103 at the first groove 1031 is greater than the residual thickness of the annular groove 103 at the second groove 1032. In other words, 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. Thus, when the battery cell experiences thermal runaway, the annular groove 103 will only break at the second groove 1032, while the annular groove 103 will remain connected at the first groove 1031, thereby preventing the entire opening part 101 from directly detaching from the battery cell under the pressure of the high-temperature airflow. This design ensures that the high-pressure gas inside the battery cell can be released in an orderly manner through the fracture point. 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. Compared with the opening part 101 being directly separated from the explosion-proof valve, it can reduce the possibility of the opening part 101 interfering with the surrounding structure.

[0052] According to one embodiment of the present invention, such as Figure 1 , Figure 2 as well as Figure 5 As shown, the annular notch 103 includes a straight section 1033 and arc-shaped sections 1034 located at both ends of the straight section 1033. The first groove 1031 is located within the straight section 1033. Compared to placing the first groove 1031 within the arc-shaped 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 completely detaching from the explosion-proof valve.

[0053] It can be understood that the shapes of the transition section 102 and the skirt 2 are adapted to the shape of the annular notch 103.

[0054] In one embodiment, such as Figure 1 , Figure 3 as well as Figure 4 As shown, the extension direction of the straight section 1033 is consistent with the length direction of the valve body 1.

[0055] According to one embodiment of the present invention, such as Figures 2 to 4 As shown, the projected area of ​​the opening part 101 on the horizontal plane is S, and the value of S ranges from 80 mm. 2 ≤S≤1000mm 2The length of the first groove 1031 is L, and the value of L is in the range of 5mm ≤ L ≤ 15mm; the cross-sectional area of ​​the bottom of the first groove 1031 along its length is S1; the relationship between S1, L, and S satisfies: 2.7 × 10 -4 mm≤(L×S1) / S≤8.0×10 -4 mm. In this embodiment, the size of the annular notch 103 at the first groove 1031 is set according to the above parameters. Under the same opening pressure, the residual thickness of the annular notch 103 at the second groove 1032 can be significantly increased, thereby improving the overall structural strength of the explosion-proof valve and reducing the risk of abnormal cracking or premature opening of the explosion-proof valve. Specifically, the explosion-proof valve is designed with a first groove 1031 and a second groove 1032. The opening method is that after the second groove 1032 breaks, the opening part 101 of the explosion-proof valve flips over, thereby allowing the high-temperature and high-pressure gas flow to be discharged smoothly. After flipping, the residual material at the bottom of the first groove 1031 of the explosion-proof valve is connected to the cover body of the battery cell cover plate 3, thereby allowing the explosion-proof valve to open according to the designed path. Then, by reasonably setting the length of the first groove 1031 and the cross-sectional area S1 of the residual material at the bottom of the first groove 1031 according to the above parameters, the opening pressure of explosion-proof valves with the same structure and the same effective opening area can be reduced to the minimum. In order to keep the opening pressure of the explosion-proof valve within the original design range, the thickness of the remaining material at the second groove 1032 of the explosion-proof valve can be increased, thereby improving the resistance of the second groove 1032 of the explosion-proof valve to external tensile deformation.

[0056] According to one embodiment of the present invention, such as Figure 2 and Figure 3 As shown, along the thickness direction of the valve body 1, the thickness of the residual material at the bottom of the first groove 1031 is H, and the value range of H is: 0.09mm≤H≤0.23mm; along the width direction of the first groove 1031, the width of the residual material at the bottom of the first groove 1031 is W, and the value range of W is: 0.05mm≤W≤0.12mm; the relationship between W, H, and S1 satisfies: S1=W×H. In this embodiment, by setting H and W according to the above parameters, it can be ensured that under the same opening pressure, the residual thickness of the annular notch 103 at the second groove 1032 is greater, thereby ensuring that the explosion-proof valve will not open prematurely due to insufficient strength at the notch before reaching the set opening pressure.

[0057] According to one embodiment of the present invention, such as Figure 2 and Figure 3As shown, in the thickness direction of the valve body 1, the thickness of the opening part 101 is D, and the value range of the thickness D of the opening part 101 is 0.15mm≤D≤0.32mm; the relationship between D and H satisfies: 0.05mm≤(DH)≤0.12mm; the thickness of the residual material at the bottom of the second groove 1032 is E, and the relationship between E and H satisfies: E / H≥0.45. In this embodiment, the opening part 101 is set according to the above parameters, which can ensure that the opening part 101 has a certain strength. When the air pressure difference is generated during normal operation of the battery cell, the opening part 101 can withstand a certain pressure by its own strength, and will not easily deform due to being too thin. And the thickness H of the residual material at the bottom of the first groove 1031 is set according to the above parameters, which can make the opening part 101 stably connected with the transition part 102 in the open state, and prevent the opening part 101 from completely separating from the transition part 102. Furthermore, by setting the difference between D and H according to the above parameters, it is possible to ensure that the opening part 101 can be stably connected to the transition part 102 through the bottom of the first groove 1031, while also allowing the stress at the annular groove 103 to be evenly diffused onto the opening part 101. Secondly, by setting H and E according to the above parameters, it is possible to increase the groove thickness of the annular groove 103 at the second groove 1032 (i.e., the thickness E of the residual material at the bottom of the second groove 1032) while keeping the opening pressure of the explosion-proof valve constant. This avoids the explosion-proof valve from opening erroneously during normal operation pressure fluctuations of the battery cell due to excessively thin grooves, thereby improving the accuracy and stability of the explosion-proof valve's operation.

[0058] According to one embodiment of the present invention, such as Figure 2 and Figure 3 As shown, the design opening pressure of the explosion-proof valve is 0.7 MPa to 1.1 MPa; the thickness E of the residual material at the bottom of the second groove 1032 is in the range of E ≥ 0.06 mm. An appropriate thickness of the residual material at the bottom ensures that the second groove 1032 can break open smoothly when the design opening pressure is reached, while preventing premature opening due to excessively thin residual material during normal operating pressure fluctuations. If the value of E is too small, slight pressure changes during normal cell operation may cause the second groove 1032 to rupture, rendering the explosion-proof valve ineffective. E ≥ 0.06 mm ensures that the second groove 1032 remains intact under normal operating conditions and opens promptly under extreme pressure. Combined with the first groove 1031, this maintains the connection between the opening part 101 and the transition part 102 after opening, ensuring the orderly discharge of high-pressure gas inside the cell and effectively improving the safety performance of the explosion-proof valve under complex operating conditions.

[0059] According to one embodiment of the present invention, such as Figure 1 , Figure 3 and Figure 5As shown, the opening portion 101 protrudes from the upper surface of the transition portion 102 and its cross-sectional shape is arc-shaped. During the normal operation of the battery cell, a certain amount of gas is generated inside the battery cell, creating a pressure difference between the inside of the battery cell and the external environment. Therefore, before this gas is discharged from the battery cell, it will continue to act on the opening portion 101, causing the opening portion 101 to tend to move or deform away from the battery cell electrode group. As a result, the groove on the explosion-proof valve may break prematurely under the pull of the opening portion 101. Based on this, in this embodiment, the opening portion 101 protrudes from the transition portion 102, which can reserve space for the deformation that the opening portion 101 may undergo during the normal operation of the battery cell, preventing the opening portion 101 from generating a pulling force on the annular groove 103 due to deformation during battery cell operation, thereby avoiding the situation of lifting to open or abnormal breakage. In addition, by making the cross-section of the opening part 101 into an arc shape, the stress acting on the annular notch 103 can be evenly distributed to the opening part 101 in a timely manner, so as to avoid abnormal cracking or premature opening caused by stress concentration at the annular notch 103.

[0060] According to one embodiment of the present invention, such as Figure 1 , Figure 3 and Figure 5 As shown, the opening portion 101 transitions evenly from its periphery to its top. This even transition means that the stress acting on each area of ​​the annular notch 103 can be gradually transmitted along the curved surface of the opening portion 101 towards the top, resulting in relatively balanced pressure across the annular notch 103 and preventing stress concentration in any area that could lead to premature breakage. Furthermore, the even transition from the periphery to the top of the opening portion 101 also ensures that the pressure is evenly distributed across it, preventing excessive local stress that could cause excessive deformation and thus avoiding premature breakage of the annular notch 103 due to stretching caused by deformation.

[0061] According to an embodiment of the present invention, on the other hand, such as Figure 6 As shown, a battery cell cover plate 3 is also provided, including: a cover plate body and the aforementioned explosion-proof valve. Specifically, the cover plate body is provided with a mounting hole; the aforementioned explosion-proof valve is disposed in the mounting hole. This battery cell cover plate 3, including the aforementioned explosion-proof valve, has all the beneficial technical effects of the battery cell cover plate 3, which will not be elaborated further here.

[0062] According to an embodiment of the present invention, on the other hand, such as Figure 6 As shown, a battery cell is also provided, comprising: a housing 4 and a battery cell cover 3. Specifically, an opening 401 is provided on one side of the housing 4; the aforementioned battery cell cover 3 covers and seals the opening 401. This battery cell, including the battery cell cover 3 as described above, possesses all the beneficial technical effects of the battery cell, which will not be elaborated further here.

[0063] The technical effects of the present invention will be described below with reference to specific embodiments and comparative examples.

[0064] Table 1: The design opening pressure of the explosion-proof valve is 0.9±0.2Mpa, and the design requirement is E≥65μm.

[0065]

[0066]

[0067] Although embodiments of the 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 invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. An explosion-proof valve, characterized in that, include: The valve body includes an opening portion and a transition portion connected to the periphery of the opening portion; an annular groove is provided between the opening portion and the transition portion surrounding the opening portion; A skirt hem, which connects to the transition portion and surrounds the periphery of the transition portion; Along the width direction of the explosion-proof valve, the total width of the explosion-proof valve is A, and the value of A is 8mm≤A≤40mm; the width of the skirt is B, and the value of B is 0.7mm≤B≤3mm; the width of the transition part is C, and the value of C is 0.5mm≤C≤3mm; the relationship between A, B and C satisfies: 0.05≤B / A≤0.12, 0.04≤C / (A-2B)≤0.15; The annular groove includes a first groove and a second groove connected to the first groove, and the first groove and the second groove are connected end to end. In the thickness direction of the valve body, the bottom of the first groove is higher than the bottom of the second groove. The projected area of ​​the opening portion on the horizontal plane is S, and the value of S ranges from 80mm. 2 ≤S≤1000mm 2 The length of the first groove is L, and the value of L is in the range of 5mm ≤ L ≤ 15mm; the cross-sectional area of ​​the residual material at the bottom of the first groove along its length is S1; the relationship between S1, L, and S satisfies: 2.7 × 10⁻⁶ -4 mm≤(L×S1) / S≤8.0×10 -4 mm; Along the thickness direction of the valve body, the thickness of the residual material at the bottom of the first groove is H; along the width direction of the first groove, the width of the residual material at the bottom of the first groove is W; the relationship between W, H and S1 satisfies: S1=W×H.

2. The explosion-proof valve according to claim 1, characterized in that, The annular groove includes a straight section and arc-shaped sections located at both ends of the straight section, and the first groove is located within the straight section.

3. The explosion-proof valve according to claim 1, characterized in that, The range of H is 0.09mm ≤ H ≤ 0.23mm; the range of W is 0.05mm ≤ W ≤ 0.12mm.

4. The explosion-proof valve according to claim 3, characterized in that, In the thickness direction of the valve body, the thickness of the opening part is D, and the value range of the thickness D of the opening part is 0.15mm≤D≤0.32mm; the relationship between D and H satisfies: 0.05mm≤(DH)≤0.12mm; the thickness of the residual material at the bottom of the second groove is E, and the relationship between E and H satisfies: E / H≥0.

45.

5. The explosion-proof valve according to any one of claims 1 to 4, characterized in that, The opening portion protrudes from the upper surface of the transition portion and has an arc-shaped cross-section.

6. The explosion-proof valve according to claim 5, characterized in that, The opening portion transitions evenly from its perimeter to its top.

7. A battery cell cover plate, characterized in that, include: The cover plate body is provided with mounting holes; The explosion-proof valve according to any one of claims 1 to 6 is disposed within the mounting hole.

8. A battery cell, characterized in that, include: The casing has an opening on one side; The cell cover plate of claim 7 covers and seals the opening.

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