Pressure relief valve, cover plate assembly, and battery

Abstract

The present application relates to the technical field of battery, and discloses a pressure relief valve, a cover plate assembly and a battery.The pressure relief valve comprises a valve body, a burst score arranged on the valve body, the burst score surrounding at least a part of the circumference of the valve body, and a reinforcing ring region arranged on the valve body and spaced from the burst score, the reinforcing ring region being annular and arranged around the circumference of the valve body, the reinforcing ring region comprising a plurality of groove segments arranged along the circumference thereof, and the groove segments having a depth of recess along the thickness direction that is less than the depth of recess along the thickness direction of the burst score.The groove segments in the reinforcing ring region can eliminate stress during the forming process of the pressure relief valve, improve the stress on the valve body, strengthen the structural strength of the valve body, and the plurality of groove segments arranged intermittently in the reinforcing ring region collectively form an annulus, thereby improving the structural strength of the valve body along the circumference thereof, avoiding excessive damage to the structural strength of the valve body, increasing the stability of the structure of the pressure relief valve, and improving the deformation resistance of the pressure relief valve.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to a pressure relief valve, a cover plate assembly, and a battery. Background Technology

[0002] Batteries are susceptible to thermal runaway during use. To improve battery safety, a pressure relief valve is installed on the battery cover or casing. This valve opens when the internal pressure reaches a certain level to release the high-temperature, high-pressure gases generated during thermal runaway, ensuring proper venting and pressure relief and preventing explosion due to excessive internal pressure. The pressure relief valve typically has scoring; when the internal pressure is high, the valve breaks at these scoring points, opening the valve. However, the scoring and the valve's relatively thin design result in poor structural strength and deformation resistance. Even when the internal pressure is below the valve's opening threshold, abnormal deformation or even rupture can occur, affecting its proper function and consequently impacting battery safety and lifespan. Summary of the Invention

[0003] In view of this, the present invention provides a pressure relief valve, a cover plate assembly, and a battery to solve the problem of poor deformation resistance of the pressure relief valve.

[0004] In a first aspect, the present invention provides a pressure relief valve, comprising: a valve body; a bursting groove disposed on the valve body, the bursting groove surrounding at least a portion of the circumferential region of the valve body; and a reinforcing ring region disposed on the valve body and spaced apart from the bursting groove, the reinforcing ring region being annular and surrounding the circumferential region of the valve body, the reinforcing ring region including a plurality of groove segments spaced apart along its circumference, the recess depth of the groove segments along the thickness direction being less than the recess depth of the bursting groove along the thickness direction.

[0005] Beneficial effects: By setting bursting marks on the valve body, a bursting thinning zone is formed, facilitating the smooth opening of the pressure relief valve when the gas pressure inside the battery reaches the preset pressure value. Simultaneously, by setting reinforcing rings spaced apart from the bursting marks on the valve body, the grooves in the reinforcing rings are formed by recesses in a portion of the valve body surface. This eliminates stress during the valve's manufacturing process, improves the valve body's stress distribution, and strengthens its structural strength. Furthermore, the recess depth of the grooves in the reinforcing rings is less than the recess depth of the bursting marks, ensuring that the residual thickness corresponding to the grooves on the valve body is greater than the residual thickness corresponding to the bursting marks, thus preventing bursting. The grooved area remains the weakest region on the pressure relief valve. While ensuring the reinforcement effect of the grooved section on the valve body structure, it avoids affecting the opening pressure of the pressure relief valve. Furthermore, the multiple grooved sections intermittently set in the reinforcing ring area together form a ring, which can improve the overall structural strength of the valve body circumferentially. The thickness of the interval area between two adjacent grooved sections is relatively large compared to the residual thickness after the grooves are set, resulting in relatively greater structural strength. This avoids excessive damage to the valve body structure strength caused by setting the entire reinforcing ring area as a continuous groove, thereby increasing the stability of the pressure relief valve structure, improving its resistance to deformation, improving the flatness of the valve body, and enhancing the reliability of the pressure relief valve.

[0006] In one optional implementation, along the circumference of the reinforcing ring region, the total arc length of the plurality of groove segments is A1, and the perimeter of the reinforcing ring region is A2, wherein A1 and A2 satisfy the relationship: 0.3≤A1 / A2≤0.9.

[0007] Beneficial effects: By rationally setting the proportion of the groove segment in the circumferential direction of the reinforcing ring area, it is possible to ensure that the reinforcing ring area has a sufficient reinforcing effect on the structural strength of the valve body, while avoiding excessive damage to the overall structure of the valve body, which would make the valve body weaker. This optimizes the structural reinforcement effect of the reinforcing ring area on the valve body and improves the reliability and stability of the pressure relief valve.

[0008] In one alternative implementation, the number of slots is three.

[0009] Beneficial effects: Ensuring that the groove segments are evenly distributed circumferentially along the reinforcing ring area can avoid excessive damage to the structural strength of the valve body due to too few groove segments or excessive continuity, and can also avoid increasing the processing difficulty due to too many groove segments, thereby effectively improving the uniformity of the reinforcing effect of the reinforcing ring area on the structural strength of the valve body.

[0010] In one alternative implementation, the reinforcing ring region is a circular ring.

[0011] Beneficial effects: The ring is easy to process and form, and the stress is uniform. Along the circumference of the ring, the residual thickness of each part of the groove is consistent, which helps to improve the processing quality, ensure the consistency of the strengthening effect of the reinforcing ring area on the structural strength of the valve body along the circumference, and improve the reliability of the pressure relief valve.

[0012] In one optional embodiment, the valve body has a dimension of H0 along the thickness direction, and the blasting mark has a recess depth of H1 along the thickness direction, wherein H1 and H0 satisfy the following condition: 40 μm ≤ H0 - H1 ≤ 150 μm.

[0013] And / or, the valve body has a dimension of H0 along the thickness direction, and the groove has a recess depth of H2 along the thickness direction, wherein H2 and H0 satisfy the following condition: 1 / 3 ≤ H2 / H0 ≤ 2 / 3.

[0014] Beneficial effects: By limiting the value of H0-H1 to the range of 40 μm to 150 μm, and reasonably setting the difference range between the indentation depth H1 of the explosion mark along the thickness direction and the dimension H0 of the valve body along the thickness direction, it can ensure that the pressure relief valve opens smoothly when the internal gas pressure of the battery reaches the preset pressure value, and also avoid the pressure relief valve from opening accidentally during normal battery use, thereby improving the reliability and stability of the pressure relief valve.

[0015] And / or, by limiting the value of H2 / H0 to within the range of 1 / 3 to 2 / 3, the ratio range between the recess depth H2 of the groove segment along the thickness direction and the dimension H0 of the valve body along the thickness direction can be reasonably set. This can ensure that the groove segment effectively eliminates the stress during the processing and forming of the pressure relief valve, and can also avoid excessive damage to the overall structure of the valve body caused by excessive recess depth of the groove segment. This optimizes the structural reinforcement effect of the groove segment on the valve body and improves the reliability and stability of the pressure relief valve.

[0016] In one optional embodiment, the value range of the valve body dimension H0 along the thickness direction is: 0.15mm≤H0≤0.35mm.

[0017] Beneficial effects: It can ensure that the valve body itself has sufficient structural strength, improve the reliability of the pressure relief valve, avoid excessive weight of the valve body, and help control costs.

[0018] In one optional embodiment, the annular shape of the blasting mark is concentric with the reinforcing ring area, and the distance between the blasting mark and the reinforcing ring area is B, wherein the value of B is in the range of 0.5 mm ≤ B ≤ 5 mm.

[0019] Beneficial effects: By setting the bursting notch and the reinforcing ring area concentrically, the spacing between the reinforcing ring area and the bursting notch is equal at all positions along the circumference of the valve body. This facilitates processing and further avoids mutual interference between the reinforcing ring area and the bursting notch during the forming process, improving reliability. It also makes the reinforcing effect of the reinforcing ring area on the valve body more uniform, preventing the valve body from having weak structural strength in a certain direction. By limiting B to a value within the range of 0.5 mm to 5 mm, the spacing between the bursting notch and the reinforcing ring area can be reasonably set. This ensures that the reinforcing ring area has a sufficient reinforcing effect on the structural strength of the area near the bursting notch, while avoiding the reinforcement effect being affected by an excessively large spacing between the reinforcing ring area and the bursting notch.

[0020] In one alternative embodiment, the blasting marks are C-shaped;

[0021] And / or, the reinforcing ring area is disposed around the side of the blasting mark near the center of the valve body, or the reinforcing ring area is disposed around the side of the blasting mark away from the center of the valve body;

[0022] And / or, the pressure relief valve further includes a welded portion that surrounds and is connected to the outer periphery of the valve body, the welded portion being adapted to be welded to the cover plate body.

[0023] Beneficial effects: By setting the bursting marks in a "C" shape, while ensuring the pressure relief capacity, it can be ensured that the structure of the pressure relief area located inside the inner ring of the bursting marks on the valve body will not fly out as a whole when the pressure relief valve is opened, thereby avoiding secondary damage to the surrounding battery or other structures and improving safety.

[0024] And / or, by setting the reinforcing ring area on the side of the explosion mark closer to the center of the valve body, it can be ensured that the reinforcing ring area can effectively strengthen the structural strength of the valve body, and that the area enclosed by the explosion mark has sufficient area, that is, that the pressure relief valve has sufficient pressure relief area, thereby ensuring that the thermal runaway flue gas of the battery cell can be discharged in time and improving safety; or, by setting the reinforcing ring area on the side of the explosion mark away from the center of the valve body, the structural strength between the explosion mark and the edge of the valve body can be strengthened, which can also effectively improve the structural strength of the pressure relief valve;

[0025] And / or, by connecting the welded part around the outer periphery of the valve body, the pressure relief valve and the cover plate body can be assembled and welded, which can ensure the welding strength, avoid the welding from affecting the valve body and the burst marks, and further improve the reliability of the pressure relief valve.

[0026] Secondly, the present invention also provides a cover plate assembly, comprising: a cover plate body having a pressure relief hole thereon; and the aforementioned pressure relief valve disposed in the pressure relief hole. Since the cover plate assembly includes a pressure relief valve and has the same effect as a pressure relief valve, it will not be described further here.

[0027] Thirdly, the present invention also provides a battery, comprising: a housing having an open end; an electrode assembly disposed within the inner cavity of the housing; and the aforementioned cover assembly, the cover assembly covering the open end of the housing. Since the battery includes the cover assembly and has the same effect as the cover assembly, it will not be described further here. Attached Figure Description

[0028] 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.

[0029] Figure 1 This is a schematic diagram of the structure of a pressure relief valve according to an embodiment of the present invention;

[0030] Figure 2 for Figure 1 The top view of the pressure relief valve shown;

[0031] Figure 3 for Figure 2 A cross-sectional view along the EE direction;

[0032] Figure 4 for Figure 3 A magnified view of part of F;

[0033] Figure 5 for Figure 1 A schematic diagram of the pressure relief valve from a bottom view;

[0034] Figure 6 This is a schematic diagram of the structure of a cover plate assembly according to an embodiment of the present invention;

[0035] Figure 7 for Figure 6 Top view of the cover plate assembly shown;

[0036] Figure 8 for Figure 7 Cross-sectional view along the GG direction;

[0037] Figure 9 for Figure 8 A magnified view of part of J;

[0038] Figure 10 for Figure 6 The diagram shows the positional relationship between the pressure relief valve and the cover plate body before assembly.

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

[0040] 1. Valve body; 2. Explosion marks; 3. Reinforcing ring area; 301. Groove section; 302. Second connecting section; 4. Welded part; 5. Cover plate body; 501. Pressure relief hole; 502. Liquid injection hole; 6. Pole post; 7. Valve patch; 8. First plastic part; 801. Vent hole. 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 pressure relief valve is a crucial component of a battery. Research has revealed that the grooves on the valve's construction can compromise its structural strength. Furthermore, stress is generated during the valve's manufacturing process. Additionally, during normal use, changes in internal battery pressure cause the valve to bulge outwards and inwards in alternating deformations. Since pressure relief valves are typically made of aluminum with a relatively thin profile, their structural strength is relatively weak. Over time, the valve is prone to damage, affecting its normal operation and consequently impacting battery safety and lifespan.

[0043] The following is combined Figures 1 to 10 The following describes embodiments of the present invention.

[0044] According to an embodiment of the present invention, in one aspect, a pressure relief valve is provided, such as... Figures 1 to 5 As shown, the pressure relief valve includes: a valve body 1, burst grooves 2, and a reinforcing ring region 3. The burst grooves 2 are disposed on the valve body 1, surrounding at least a portion of the circumference of the valve body 1. The reinforcing ring region 3 is disposed on the valve body 1 and spaced apart from the burst grooves 2. The reinforcing ring region 3 is annular and surrounds the circumference of the valve body 1. The reinforcing ring region 3 includes multiple groove segments 301 spaced apart circumferentially. The depth of the groove segments 301 along the thickness direction is less than the depth of the burst grooves 2 along the thickness direction. Here, the thickness direction refers to the thickness direction of the valve body 1, specifically... Figures 3 to 4 The middle arrow points to the "thickness direction".

[0045] The pressure relief valve of this embodiment, by providing burst grooves 2 on the valve body 1, creates a burst thinning zone on the valve body 1, facilitating smooth opening of the pressure relief valve when the gas pressure inside the battery reaches a preset pressure value. Simultaneously, by providing reinforcing ring regions 3 spaced apart from the burst grooves 2 on the valve body 1, the grooves 301 in the reinforcing ring regions 3 are formed by recesses in a portion of the surface of the valve body 1. This eliminates stress during the valve's manufacturing process, improves the stress on the valve body 1, and strengthens its structural strength. Furthermore, the recess depth of the grooves 301 in the reinforcing ring regions 3 is less than the recess depth of the burst grooves 2, ensuring that the residual thickness on the valve body 1 corresponding to the grooves 301 is greater than the residual thickness corresponding to the burst grooves 2. The thickest part, the explosion mark 2, is still the weakest area on the pressure relief valve. While ensuring the reinforcement effect of the groove segment 301 on the valve body 1 structure, it avoids affecting the opening pressure of the pressure relief valve. In addition, the multiple groove segments 301 set in the middle of the reinforcing ring area 3 together form a ring, which can improve the overall structural strength of the valve body 1 along the circumference. The thickness of the interval area between two adjacent groove segments 301 is relatively large compared with the residual thickness after the groove segment 301 is set, and the structural strength is relatively large. This can avoid excessive damage to the structural strength of the valve body 1 by setting the entire reinforcing ring area 3 as a continuous groove, thereby increasing the stability of the pressure relief valve structure, improving the deformation resistance of the pressure relief valve, improving the flatness of the valve body 1, and improving the reliability of the pressure relief valve.

[0046] It should be noted that the reinforcing ring region 3 plays a role in relieving stress during the annealing process of the pressure relief valve. The valve body 1 has two surfaces arranged opposite each other along the thickness direction. The bursting mark 2 and the reinforcing ring region 3 are both formed by a portion of one of the two surfaces of the valve body 1 recessed along the thickness direction. The bursting mark 2 and the reinforcing ring region 3 can be set on the same surface of the valve body 1 or on two opposite surfaces. Preferably, the bursting mark 2 and the reinforcing ring region 3 can be set on the surface of the valve body 1 facing the outside of the housing, and the surface of the pressure relief valve facing the inside of the housing is as follows. Figure 5 The plane shown.

[0047] It should be noted that the residual thickness refers to the thickness of the solid part remaining along the thickness direction after the explosion mark 2 or groove 301 is opened on the valve body 1. The residual thickness of the explosion mark 2 is the smallest and the thinnest. When the gas pressure inside the battery reaches the preset pressure value, the pressure relief valve breaks first at the explosion mark 2. The area enclosed by the explosion mark 2 is blown up by the gas, the pressure relief valve opens, and an exhaust channel is formed to facilitate the discharge of high-pressure gas inside the battery, prevent the battery from exploding, and reduce losses.

[0048] In one embodiment, further combination Figures 1 to 2As shown, the burst mark 2 is C-shaped. It should be noted that the burst mark 2 is an annular portion, and the area on the valve body 1 located on the inner side of the annulus forms a pressure relief zone. A first connecting segment is also present on the annulus containing the burst mark 2. The first connecting segment connects end-to-end with the burst mark 2 to form a closed annulus, thus encircling the valve body 1. The thickness dimension of the first connecting segment is equal to the thickness dimension of the valve body 1. Therefore, the structural strength of the first connecting segment is greater than the residual thickness on the valve body 1 corresponding to the burst mark 2. When the internal gas pressure of the battery increases and it ruptures at the burst mark 2, the first connecting segment will not break, preventing the entire structure from flying out. Therefore, by setting the burst mark 2 to a C-shape, while ensuring pressure relief capacity, it is ensured that when the pressure relief valve opens, the structure of the pressure relief area on the valve body 1 located on the inner side of the inner ring of the burst mark 2 will not fly out entirely, thereby avoiding secondary damage to the surrounding battery or other structures and improving safety.

[0049] In other embodiments, the bursting notch 2 can also be annular, arranged around the circumference of the valve body 1, which can also ensure the pressure relief capacity of the pressure relief valve.

[0050] In one embodiment, along the circumference of the reinforcing ring region 3, the total arc length of the plurality of groove segments 301 is A1, and the circumference of the reinforcing ring region 3 is A2, wherein A1 and A2 satisfy the relationship: 0.3≤A1 / A2≤0.9. It should be noted that the plurality of groove segments 301 are discontinuously distributed along the circumference of the reinforcing ring region 3, and the second connecting segment 302 is the part of the reinforcing ring region 3 without grooves. The dimension of the second connecting segment 302 along the thickness direction is equal to the thickness of the valve body 1. If A1 / A2 is less than 0.3, the total arc length of all groove segments 301 accounts for too small a proportion of the perimeter of the reinforcing ring area 3, and the reinforcing ring area 3 has a limited effect on strengthening the structure of the valve body 1. If A1 / A2 is greater than 0.9, the total arc length of all groove segments 301 accounts for too large a proportion of the reinforcing ring area 3, causing excessive damage to the overall structure of the valve body 1, losing the reinforcing effect of groove segments 301 on the structural strength of the valve body 1, and instead making the valve body 1 weaker, affecting the normal use of the pressure relief valve.

[0051] Therefore, by limiting the value of A1 / A2 to the range of 0.3 to 0.9, and reasonably setting the proportion of the groove segment 301 in the circumferential direction of the reinforcing ring region 3, it is possible to ensure that the reinforcing ring region 3 has a sufficient reinforcing effect on the structural strength of the valve body 1, while avoiding excessive damage to the overall structure of the valve body 1, which would make the valve body 1 weaker. This optimizes the structural reinforcement effect of the reinforcing ring region 3 on the valve body 1 and improves the reliability and stability of the pressure relief valve.

[0052] Optionally, the value of A1 / A2 can be any value among 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, and 0.9, or a value between any two values.

[0053] In one embodiment, the number of groove segments 301 is three. The number of second connecting segments 302 is equal to the number of groove segments 301. By setting three intermittently arranged groove segments 301 in the reinforcing ring area 3, the number of second connecting segments 302 is three, ensuring that the groove segments 301 are evenly distributed along the circumference of the reinforcing ring area 3. This avoids both an insufficient number of groove segments 301 and excessive continuity, which would excessively damage the structural strength of the valve body 1, and an excessive number of groove segments 301, which would increase the processing difficulty. Thus, it effectively improves the uniformity of the reinforcing effect of the reinforcing ring area 3 on the structural strength of the valve body 1.

[0054] In one embodiment, the arc length of each groove segment 301 is equal, and the arc length of the second connecting segment 302 between two adjacent groove segments 301 is also equal. This ensures that the reinforcing effect of the reinforcing ring area 3 on the valve body 1 is consistent in all directions, and avoids the valve body 1 having weak structural strength in a certain direction, which would affect the overall performance of the pressure relief valve.

[0055] It should be noted that the number of slots 301 is at least two, preferably three, but can also be four, five or more.

[0056] In one embodiment, the reinforcing ring region 3 is a circular ring. A circular ring is easy to process and shape, and the stress is evenly distributed. Along the circumference of the ring, the residual thickness of each part of the groove segment 301 is consistent, which helps improve processing quality and ensures the consistency of the reinforcing effect of the reinforcing ring region 3 on the structural strength of the valve body 1 along the circumference, thus improving the reliability of the pressure relief valve. It should be noted that the valve body 1 is circular, the reinforcing ring region 3 is a circular ring, and the bursting mark 2 is a portion of the circular ring, which facilitates processing, provides a better reinforcing effect, and results in higher opening reliability of the pressure relief valve.

[0057] In other embodiments, the pressure relief valve can also be racetrack-shaped. Correspondingly, the bursting mark 2 is at least part of the racetrack shape, and the reinforcing ring 3 is a racetrack-shaped ring. This can also ensure the reinforcing effect of the reinforcing ring 3 on the structural strength of the valve body 1 and improve the reliability of the pressure relief valve. However, the consistency of the residual thickness of the bursting mark 2 along its axial direction is slightly poor, and the consistency of the residual thickness of the reinforcing ring 3 along its circumference is slightly poor.

[0058] In one embodiment, the dimension of the valve body 1 along the thickness direction is H0, and the depth of the bursting mark 2 along the thickness direction is H1, wherein H1 and H0 satisfy the following condition: 40 μm ≤ H0 - H1 ≤ 150 μm. Here, the thickness direction refers to... Figures 3 to 4The middle arrow indicates the "thickness direction". H0 is the thickness of valve body 1, H1 is the depth of the explosion mark 2, and H0-H1 is the residual thickness of the pressure relief valve along the thickness direction corresponding to the explosion mark 2. The value of H0-H1 directly affects the opening pressure of the pressure relief valve. For example, when H0-H1 equals 50 μm, the opening pressure of the pressure relief valve is 0.4 MPa, and when H0-H1 equals 100 μm, the opening pressure of the pressure relief valve is 0.8 MPa to 0.9 MPa. If H0-H1 is less than 40 μm, the residual thickness at the explosion mark 2 is too small, and the structural strength is too weak. During normal battery use, it may break due to slight deformation, causing the pressure relief valve to open incorrectly, affecting the normal use and safety of the battery. If H0-H1 is greater than 150 μm, the residual thickness at the explosion mark 2 is too large, making it difficult to break, causing the pressure relief valve to fail to open in time, affecting the pressure relief effect.

[0059] Therefore, by limiting the values ​​of H0-H1 to the range of 40 μm to 150 μm, and reasonably setting the difference range between the indentation depth H1 of the explosion mark 2 along the thickness direction and the dimension H0 of the valve body 1 along the thickness direction, it is possible to ensure that the pressure relief valve opens smoothly when the internal gas pressure of the battery reaches the preset pressure value, and to avoid the pressure relief valve from opening accidentally during normal battery use, thereby improving the reliability and stability of the pressure relief valve.

[0060] Optionally, H0-H1 can be any value among 40 μm, 50 μm, 60 μm, 80 μm, 100 μm, 120 μm, 140 μm, and 150 μm, or a value between any two values.

[0061] In one embodiment, the valve body 1 has a thickness dimension of H0, and the groove 301 has a depth of H2 along its thickness direction. H2 and H0 satisfy the following condition: 1 / 3 ≤ H2 / H0 ≤ 2 / 3. H2 and H0 have the same unit, which can be mm. It should be noted that H0 is the thickness of the valve body 1, and H2 is the depth of the groove 301. If H2 / H0 is less than 1 / 3, the depth of the groove 301 is too small relative to the thickness of the valve body 1, failing to effectively eliminate stress during the pressure relief valve's manufacturing process and having limited structural reinforcement effect on the valve body 1. If H2 / H0 is greater than 2 / 3, the depth of the groove 301 is too large relative to the thickness of the valve body 1, resulting in a small residual thickness corresponding to the groove 301, leading to insufficient structural strength. This makes the groove 301 a weak area on the valve body 1, negatively impacting the structural strength of the valve body 1 and affecting the normal operation of the pressure relief valve.

[0062] Therefore, by limiting the value of H2 / H0 to within the range of 1 / 3 to 2 / 3, and reasonably setting the ratio range between the recess depth H2 of the groove segment 301 along the thickness direction and the dimension H0 of the valve body 1 along the thickness direction, it is possible to ensure that the groove segment 301 effectively eliminates the stress during the processing and forming of the pressure relief valve, while avoiding excessive damage to the overall structure of the valve body 1 due to excessive recess depth of the groove segment 301. This optimizes the structural reinforcement effect of the groove segment 301 on the valve body 1 and improves the reliability and stability of the pressure relief valve.

[0063] Optionally, the value of H2 / H0 can be any value selected from 1 / 3, 2 / 5, 1 / 2, 4 / 7, 3 / 5, 2 / 3, or a value between any two values. Preferably, the value of H2 / H0 is 1 / 2.

[0064] In one embodiment, the value of the dimension H0 of the valve body 1 along the thickness direction is in the range of 0.15 mm ≤ H0 ≤ 0.35 mm. If H0 is less than 0.15 mm, the thickness of the valve body 1 is too small, resulting in poor structural strength; if H0 is greater than 0.35 mm, the thickness of the valve body 1 is too large, leading to excessive weight and higher cost. Therefore, by limiting H0 to a value between 0.15 mm and 0.35 mm, it is possible to ensure that the valve body 1 has sufficient structural strength, improving the reliability of the pressure relief valve, while also avoiding excessive weight and controlling costs.

[0065] Optionally, the value of H0 can be any value among 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, and 0.35 mm, or a value between any two of these. It should be noted that the larger the circumferential dimension of the pressure relief valve, the larger the value of H0.

[0066] In one embodiment, the annular bursting notch 2 is concentrically arranged with the reinforcing ring region 3, and the distance between the bursting notch 2 and the reinforcing ring region 3 is B, wherein the value of B ranges from 0.5 mm to 5 mm. It should be noted that the spacing between the reinforcing ring region 3 and the bursting notch 2 avoids interference between them, thus preventing any impact on the opening pressure of the bursting notch 2. By setting the bursting notch 2 and the reinforcing ring region 3 concentrically, it ensures that the distance between the reinforcing ring region 3 and the bursting notch 2 is equal at all positions along the circumference of the valve body 1. This facilitates processing and further avoids mutual interference between the reinforcing ring region 3 and the bursting notch 2 during the forming process, improving reliability. It also makes the reinforcing effect of the reinforcing ring region 3 on the valve body 1 more uniform, preventing the valve body 1 from having weak structural strength in a certain direction.

[0067] It should be noted that the interval between the blasting notch 2 and the reinforcing ring area 3 is annular. The distance B between the blasting notch 2 and the reinforcing ring area 3 refers to the ring width of the annular interval between the blasting notch 2 and the reinforcing ring area 3. Specifically, B is the distance between the blasting notch 2 and the reinforcing ring area 3 along the... Figures 3 to 4 The distance indicated by the "X" in the middle arrow is the radial direction of the ring formed by the reinforcing ring 3. If B is less than 0.5 mm, the distance between the bursting notch 2 and the reinforcing ring 3 is too small. During processing or use, the reinforcing ring 3 may damage the bursting notch 2, affecting the opening effect of the pressure relief valve. If B is greater than 5 mm, the distance between the bursting notch 2 and the reinforcing ring 3 is too large, and the reinforcing effect of the reinforcing ring 3 on the area near the bursting notch 2 is weakened.

[0068] Therefore, by limiting B to a value within the range of 0.5 mm to 5 mm, and reasonably setting the distance between the blasting notch 2 and the reinforcing ring area 3, it is possible to ensure that the reinforcing ring area 3 has sufficient reinforcing effect on the structural strength of the area near the blasting notch 2, while avoiding the reinforcement effect being affected by an excessively large distance between the reinforcing ring area 3 and the blasting notch 2.

[0069] Optionally, the value of B is any value among 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, and 5 mm, or a value between any two values.

[0070] In one embodiment, the reinforcing ring 3 is arranged around the side of the explosion notch 2 closest to the center of the valve body 1. It should be noted that the distance between the explosion notch 2 and the center of the valve body 1 is usually greater than the distance between the explosion notch 2 and the edge of the valve body 1. By placing the reinforcing ring 3 on the side of the explosion notch 2 closest to the center of the valve body 1, it can be ensured that the reinforcing ring 3 can effectively strengthen the structural strength of the valve body 1, and that the area enclosed by the explosion notch 2 has sufficient area, that is, it can be ensured that the pressure relief valve has sufficient pressure relief area, thereby ensuring that the thermal runaway flue gas of the battery cell can be discharged in time, improving safety.

[0071] In other embodiments, the reinforcing ring region 3 is arranged around the side of the blasting notch 2 away from the center of the valve body 1. By setting the reinforcing ring region 3 on the side of the blasting notch 2 away from the center of the valve body 1, the structural strength between the blasting notch 2 and the edge of the valve body 1 can be strengthened, which can also effectively improve the structural strength of the pressure relief valve.

[0072] In one embodiment, the pressure relief valve further includes a welded portion 4, which is connected around the outer periphery of the valve body 1 and is adapted to be welded to the cover plate body 5. By connecting the welded portion 4 around the outer periphery of the valve body 1, the assembly and welding of the pressure relief valve and the cover plate body 5 can be realized, which can ensure the welding strength and avoid the welding from affecting the valve body 1 and the burst mark 2, thereby further improving the reliability of the pressure relief valve.

[0073] In one embodiment, the dimension of the welded part 4 along the thickness direction is larger than the dimension of the valve body 1 along the thickness direction, further ensuring the welding quality. After the welded part 4 and the cover plate body 5 are assembled, they are welded into a single structure.

[0074] The following experiments verify the effect of different parameter values ​​on the performance of the pressure relief valve. The test results of the examples and comparative examples are shown in Table 1. The test indicators are as follows:

[0075] 1. Deformation of pressure relief valve: After placing the pressure relief valve in a specific tooling and cyclically pressing it with ±0.3 MPa air pressure for 10 times, the deformation of the pressure relief valve should be less than 0.3 mm (characterizing the pressure relief valve's resistance to deformation).

[0076] 2. Service life: Place the pressure relief valve in a specific fixture and input ±0.15 MPa air pressure to simulate the internal air pressure state of the battery during normal use. The pressure relief valve is required to ensure that it can withstand more than 3,000 cycles without cracking. One cycle consists of the input air pressure alternating between +0.15 MPa and -0.15 MPa.

[0077] Table 1

[0078]

[0079] As can be seen from Table 1, in Examples 1 to 8, the values ​​of A1 / A2 are all within the range of 0.3 to 0.9 as defined in this application, and the values ​​of H2 / H0 are all within the range of 1 / 3 to 2 / 3 as defined in this application. After testing, the deformation of the pressure relief valve is less than 0.3 mm, and the number of cycles is greater than 3000. The test is OK (i.e., the test is passed). The pressure relief valve has qualified anti-deformation ability and qualified service life. This indicates that the reinforcing ring 3 has a good structural reinforcement effect on the valve body 1, and the pressure relief valve has high reliability.

[0080] In Comparative Example 1, the value of A1 / A2 is 0.29, which is less than 0.3 and lower than the lower limit of the A1 / A2 value defined in this application. Therefore, it is outside the range defined in this application. The corresponding deformation of the pressure relief valve is 0.52 mm, which is greater than 0.3 mm, and the number of cycles is 2084, which is less than 3000. This means the pressure relief valve's deformation resistance and service life are both unqualified, and the test is NG (fail). It is evident that a small A1 / A2 not only affects the pressure relief valve's deformation resistance but also its service life. In Comparative Example 2, the value of A1 / A2 is 0.91, which is greater than 0.9 and higher than the upper limit of the A1 / A2 value defined in this application. Although the deformation of the pressure relief valve is less than 0.3 mm, the number of cycles is only 1954, which is less than 3000. Therefore, the service life of the pressure relief valve is unqualified, and the test is NG (fail). It is evident that a large A1 / A2 will affect the service life of the pressure relief valve.

[0081] In Comparative Example 3, the value of H2 / H0 is 0.30, which is less than 1 / 3 and lower than the lower limit of H2 / H0 value defined in this application. It is not within the range defined in this application. Although the deformation of the pressure relief valve is less than 0.3 mm, the number of cycles is 2215, which is less than 3000. The service life of the pressure relief valve is unqualified, and the test is NG (fail). It can be seen that an excessively small H2 / H0 will affect the service life of the pressure relief valve. In Comparative Example 4, the value of H2 / H0 is 0.80, which is greater than 2 / 3 and higher than the upper limit of H2 / H0 value defined in this application. It is not within the range defined in this application. The deformation of the pressure relief valve is 0.48 mm, which is greater than 0.3 mm. The number of cycles is 1536, which is less than 3000. That is, the deformation resistance of the pressure relief valve is unqualified and the service life is unqualified. The test is NG (fail). It can be seen that an excessively large H2 / H0 will not only affect the deformation resistance of the pressure relief valve, but also affect its service life.

[0082] In summary, when A1 / A2 is between 0.3 and 0.9, and H2 / H0 is between 1 / 3 and 2 / 3, it can ensure that the reinforcing ring 3 provides sufficient reinforcement to the structural strength of the valve body 1, while avoiding excessive damage to the overall structure of the valve body 1, which would make the valve body 1 weaker. This allows the pressure relief valve to have both high resistance to deformation and a long service life, ensuring good performance.

[0083] Unless otherwise stated, the values ​​of the parameters mentioned in this application can be determined using commonly used testing methods in the art. For example, the deformation of the pressure relief valve can be measured using dial indicators, high-speed camera optical methods, microscopic interferometry, etc.; the specific tooling used in testing the deformation and service life of the pressure relief valve can be lithium battery pressure testing tooling, etc. Unless otherwise stated, the test temperature for all parameters is 25°C.

[0084] According to an embodiment of the present invention, in another aspect, a cover plate assembly is also provided, such as... Figures 6 to 10 As shown, the cover plate assembly includes: a cover plate body 5 and the aforementioned pressure relief valve. A pressure relief hole 501 is provided on the cover plate body 5, which is a through hole extending through the cover plate body 5 along its thickness direction; the pressure relief valve is disposed in the pressure relief hole 501. Since the cover plate assembly includes a pressure relief valve and has the same effect as a pressure relief valve, it will not be described in detail here.

[0085] In one embodiment, the cover assembly further includes a valve patch 7, which is located on the side of the cover body away from the battery housing and attached to the surface of the pressure relief valve to protect the pressure relief valve.

[0086] In one embodiment, the cover plate body 5 is further provided with a pole hole, and the cover plate assembly also includes a pole 6, which passes through the pole hole and is electrically connected to the pole tab of the pole group.

[0087] In one embodiment, the cover plate body 5 is also provided with an injection hole 502, which is used to inject electrolyte into the battery.

[0088] In one embodiment, the cover assembly further includes a first plastic part 8, which is disposed on the side of the cover body 5 facing the inside of the battery. The first plastic part 8 is provided with an exhaust hole 801 corresponding to the pressure relief valve, so that when the battery experiences thermal runaway, the gas inside the battery is guided to the pressure relief valve through the exhaust hole 801, thereby being smoothly discharged to the outside of the battery.

[0089] According to an embodiment of the present invention, in another aspect, a battery is also provided, comprising: a housing, an electrode assembly, and the aforementioned cover assembly. The housing has an open end; the electrode assembly is disposed within the inner cavity of the housing; and the cover assembly covers the open end of the housing. Since the battery includes the cover assembly, it has the same effect as the cover assembly, and will not be described further here.

[0090] In one embodiment, the battery is a lithium-ion battery.

[0091] 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. A pressure relief valve characterized by, The valve body comprises: an explosion score provided on the valve body, the explosion score being annular and surrounding at least a partial region of the valve body in the circumferential direction; a reinforcing ring region provided on the valve body and spaced apart from the explosion score, the reinforcing ring region being annular and surrounding the valve body in the circumferential direction, the reinforcing ring region comprising a plurality of groove segments spaced apart in the circumferential direction, the groove segments having a depth of recess in the thickness direction smaller than that of the explosion score in the thickness direction; the reinforcing ring region is a circular ring; along the circumferential direction of the reinforcing ring region, the total arc length of the plurality of groove segments is A1, and the circumference of the reinforcing ring region is A2, wherein the relationship between A1 and A2 satisfies the formula: 0.3≤A1 / A2≤0.9, and the units of A1 and A2 are both mm; the valve body has a dimension in the thickness direction of H0, and the explosion score has a depth of recess in the thickness direction of H1, wherein the relationship between H1 and H0 satisfies: 40 μm≤H0-H1≤150 μm, and the unit of H1 is μm; the valve body has a dimension in the thickness direction of H0, and the groove segments have a depth of recess in the thickness direction of H2, wherein the relationship between H2 and H0 satisfies: 1 / 3≤H2 / H0≤2 / 3, and the units of H2 and H0 are both mm; the dimension H0 of the valve body in the thickness direction ranges from 0.15 mm to 0.35 mm; the annular explosion score is concentrically arranged with the reinforcing ring region, and the distance between the explosion score and the reinforcing ring region is B, wherein the unit of B is mm, and the value of B ranges from 0.5 mm to 5 mm; the reinforcing ring region is annularly arranged on the side of the explosion score close to the center of the valve body, or the reinforcing ring region is annularly arranged on the side of the explosion score away from the center of the valve body. The number of groove segments is three.

2. The pressure relief valve of claim 1, wherein The explosion score is in the shape of a "C".

3. The pressure relief valve according to any one of claims 1 to 2, characterized in that And / or, the pressure relief valve further comprises a welding portion annularly connected to the outer circumferential side of the valve body, and the welding portion is adapted to be welded with the cover plate body. The cover plate assembly comprises:

4. A cover plate assembly characterized by, a cover plate body, the cover plate body being provided with a pressure relief hole; the pressure relief valve according to any one of claims 1 to 3, the pressure relief valve being arranged in the pressure relief hole. The cover plate assembly comprises:

5. A battery, characterized by a housing having an open end; a pole group arranged in the inner cavity of the housing; the cover plate assembly according to claim 4, the cover plate assembly being arranged on the open end of the housing. ​

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