Anti-explosion valve, cover plate assembly and battery

Abstract

The utility model relates to the technical field of batteries, and discloses an anti-explosion valve, a cover plate assembly and a battery. The explosion-proof valve comprises a valve body, the valve body comprises a welding area and a thinning area, the welding area is connected to the peripheral side of the thinning area in a surrounding mode, the thickness of the thinning area is smaller than that of the welding area, and the size of the valve body in the length direction of the valve body is A; the nick is formed in the thinning area, and the orthographic projection of the nick on the surface of the valve body is at least part of an annular shape; the sunken part is arranged in the annular inner ring area where the nick is located and located in the center of the thinning area, the sunken part is formed by sinking a part of area on the first surface of the thinning area in the direction deviating from the first surface, the size of the sunken part in the length direction of the valve body is C, and C and A meet the relational expression that C / A is larger than or equal to 1 / 3 and smaller than or equal to 1 / 2. The concave reinforcing rib is additionally arranged in the middle of the anti-explosion valve, the concave part has a reasonable size in the length direction, and the structural strength of the anti-explosion valve is improved.

Description

Technical Field

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

[0002] Explosion-proof valves are crucial components of batteries. In the event of abnormal conditions inside the battery, such as the presence of high-temperature, high-pressure gases, the explosion-proof valve acts as a controllable, directional vent to expel these gases and ensure battery safety. Current explosion-proof valves typically have grooves machined into the valve body to control the detonation threshold. When the internal pressure increases, the valve breaks at these grooves, thus opening the explosion-proof valve. However, the weaker structural strength at these grooves weakens the overall strength of the explosion-proof valve, leading to occasional breakage during normal use. This can result in electrolyte leakage, cell failure, and even the failure of the entire battery pack. Therefore, it is necessary to strengthen the structural integrity of the explosion-proof valve. Utility Model Content

[0003] In view of this, the present invention provides an explosion-proof valve, a cover plate assembly and a battery to solve the problem of weak structural strength of the explosion-proof valve.

[0004] In a first aspect, this utility model provides an explosion-proof valve, comprising: a valve body, including a welding area and a thinning area, wherein the welding area is connected around the outer periphery of the thinning area, the thickness of the thinning area is less than the thickness of the welding area, and the valve body has a length dimension of A; a notch formed in the thinning area, wherein the orthographic projection of the notch on the surface of the valve body is at least an annular shape; and a recessed portion disposed within the inner annular region of the notch and located at the center of the thinning area, wherein the recessed portion is formed by a portion of the first surface of the thinning area recessed in a direction away from the first surface, and the recessed portion has a length dimension of C along the length direction of the valve body, wherein C and A satisfy the relationship: 1 / 3 ≤ C / A ≤ 1 / 2.

[0005] Beneficial effects: By setting a recessed portion within the inner ring region of the annular ring containing the scoring on the thinning area, i.e., adding an inner concave reinforcing rib at the center of the explosion-proof valve, the recessed portion also reduces the stress formed on the thinning area during the processing and forming process, thereby reducing the stress on the scoring and effectively preventing the scoring from breaking under normal battery operation. This effectively increases the overall strength of the explosion-proof valve, thereby improving battery safety. Furthermore, by setting the dimension C of the recessed portion along the length direction of the valve body to satisfy the relationship 1 / 3≤C / A≤1 / 2 with the length dimension A of the valve body 1, the recessed portion has a reasonable size in the length direction. This avoids the recessed portion being too small relative to the length dimension of the valve body, which would not provide a good strengthening effect on the structural strength of the explosion-proof valve. At the same time, it also avoids the recessed portion being too close to the scoring, which would affect the scoring, thereby further increasing the structural strength of the explosion-proof valve.

[0006] In one optional embodiment, the dimension of the thinning region along the width direction of the valve body is E, and the dimension of the recess along the width direction of the valve body is F, wherein F and E satisfy the relationship: 1 / 4≤F / E≤1 / 3.

[0007] Beneficial effects: By setting the relationship between the dimension E of the thinning zone along the width direction of the valve body and the dimension F of the recess along the width direction of the valve body to satisfy 1 / 4≤F / E≤1 / 3, the recess has a reasonable dimension along the width direction. This ensures that the recess strengthens the structural strength of the thinning zone while avoiding damage to the scoring, thus guaranteeing the strengthening effect of the recess on the overall structural strength of the explosion-proof valve.

[0008] In one alternative embodiment, the thinning area is an arc-shaped surface that protrudes from the second side of the valve body toward the first side of the valve body.

[0009] Beneficial effects: By setting the thinning area as a smooth arc surface, and the arc surface protruding from the second side of the valve body towards the first side of the valve body, when the explosion-proof valve is installed on the battery, the arc surface protrudes from the side of the valve body towards the inside of the battery housing towards the outside of the housing. The high-pressure gas generated by the battery due to abnormality acts on the concave surface of the arc surface, which is conducive to the gas breaking through the explosion-proof valve, ensuring the smooth opening of the explosion-proof valve, thereby improving the safety of the battery.

[0010] In one optional embodiment, the recess depth of the recessed portion relative to the first side of the welding area is H0, wherein 0.5mm≤H0≤1.2mm.

[0011] Beneficial effects: It can ensure that the recessed part has sufficient depth to strengthen the structure of the explosion-proof valve, and can also avoid the recessed part being too deep and interfering with the plastic parts, thereby improving the overall safety of the battery.

[0012] In one optional embodiment, the thickness of the thinning region is H1, wherein 0.15mm ≤ H1 ≤ 0.18mm;

[0013] And / or, the thickness of the welded area is H2, wherein 0.45mm ≤ H2 ≤ 0.55mm;

[0014] And / or, the shortest distance from the outer edge of the notch to the outer peripheral edge of the thinning area is W, where 0.45mm≤W≤0.5mm.

[0015] Beneficial effects: By setting the thickness H1 of the thinning zone within the range of 0.15mm to 0.18mm, the thinning zone has a reasonable thickness, which can ensure that the thinning zone has sufficient structural strength and that the explosion-proof valve can be released in time, thereby ensuring the safety of the battery.

[0016] By setting the thickness H2 of the welding area within the range of 0.45mm to 0.55mm, it is possible to ensure that the welding area has sufficient structural strength and the welding quality between the welding area and the cover plate body. At the same time, it is possible to avoid excessive weight due to excessive thickness of the welding area, thereby reducing costs and preventing the explosion-proof valve from occupying too much space inside the battery, thereby improving the volumetric energy density of the battery.

[0017] By setting the shortest distance W from the outer edge of the notch to the outer periphery of the thinning zone to a value within the range of 0.45mm to 0.5mm, it is possible to ensure that the notch is successfully processed and formed, and that the notch breaks in time when the gas pressure inside the battery reaches the explosion condition. It is also possible to ensure that the actual venting area enclosed by the notch has sufficient venting area, so as to ensure that the gas inside the battery can be smoothly discharged when the explosion-proof valve is opened, thereby improving the safety of the battery.

[0018] In one optional embodiment, the thinning region further includes a connecting segment with a thickness equal to that of the thinning region. The connecting segment is connected end-to-end to the notch to surround the valve body, and the area enclosed by the notch and the connecting segment is oblong.

[0019] Beneficial effects: The connecting segment and the serration form a closed ring by connecting end to end. The connecting segment is the part of the thinned area without serration. Therefore, the strength of the connecting segment is greater than that of the serration. When the gas pressure in the battery reaches the preset pressure value and breaks, the connecting segment will not break. This can prevent the thinned area from bursting open and causing secondary damage to the surrounding battery or other structures, thereby reducing the risk.

[0020] In one optional embodiment, the oblong shape includes semicircular regions on both sides of the length direction and a rectangular region between the two semicircular regions, wherein the rectangular region has a dimension L along the length direction of the valve body, where 1 / 2 < C / L < 1.

[0021] Beneficial effects: By setting the dimension C of the recess along the length of the valve body and the dimension L of the rectangular area along the length of the valve body to satisfy the relationship 1 / 2 < C / L < 1, the recess is located within the rectangular area. This ensures that the size of the recess relative to the size of the rectangular area in the length direction has a sufficient proportion, thus ensuring the reinforcing effect of the recess on the structural strength of the explosion-proof valve. At the same time, it prevents the recess from exceeding the rectangular area and reaching the semicircular areas on both sides, which would cause the recess to be too close to the section of the scribe corresponding to the semicircular area and affect the structural strength of that part, thereby improving safety.

[0022] Secondly, this utility model also provides a cover plate assembly, comprising: a cover plate body having an explosion-proof valve hole; and the aforementioned explosion-proof valve, wherein the explosion-proof valve is installed in the explosion-proof valve hole. Since the cover plate assembly includes an explosion-proof valve and has the same effect as the explosion-proof valve, it will not be described in detail here.

[0023] In one optional embodiment, the cover plate assembly further includes: a plastic part disposed on the lower side of the cover plate body, the plastic part having a relief portion formed by a recessed area of ​​the upper surface of the plastic part, the relief portion corresponding to the recessed portion of the explosion-proof valve, the upper surface of the relief portion and the lower surface of the recessed portion being spaced apart and the distance between them being H3, wherein 0.4mm≤H3≤0.6mm.

[0024] Beneficial effects: By setting a plastic part on the lower side of the cover plate body, the plastic part separates the cover plate body from the electrode assembly, ensuring the insulation between the cover plate body and the electrode assembly body. Furthermore, by setting a clearance portion corresponding to the recessed portion on the explosion-proof valve on the side of the plastic part facing the cover plate body, the clearance portion provides clearance space for the recessed portion, preventing the recessed portion from squeezing the plastic part and affecting the assembly of the plastic part on the cover plate body or causing damage to the component. Simultaneously, by setting the upper surface of the clearance portion and the lower surface of the recessed portion at intervals, with the distance H3 between them ranging from 0.4mm to 0.6mm, sufficient vertical spacing between the lower surface of the recessed portion and the plastic part is ensured, thus preventing interference between the recessed portion and the plastic part. At the same time, excessive vertical spacing between the lower surface of the recessed portion and the plastic part prevents the vertical recess size of the clearance portion from becoming too large, thus preventing the thickness of the solid portion corresponding to the clearance portion on the plastic part from being too small in the vertical direction. This ensures that the plastic part has sufficient structural strength, further improving battery safety.

[0025] Thirdly, this utility model also provides a battery, comprising: a casing having an open end; an electrode assembly disposed inside the casing; and the aforementioned cover assembly covering the open end of the casing to close the casing. 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

[0026] To more clearly illustrate the specific embodiments of this utility model 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 this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the structure of an explosion-proof valve according to an embodiment of the present utility model;

[0028] Figure 2 for Figure 1 The top view of the explosion-proof valve shown;

[0029] Figure 3 for Figure 2 Cross-sectional view along the MM direction;

[0030] Figure 4 for Figure 1 The front view of the explosion-proof valve is shown below;

[0031] Figure 5 This is a schematic diagram of the structure of a cover plate assembly according to an embodiment of the present utility model;

[0032] Figure 6 for Figure 5 Top view of the cover plate assembly shown;

[0033] Figure 7 for Figure 6 A cross-sectional view along the NN direction;

[0034] Figure 8 for Figure 5 The front view of the cover plate assembly shown;

[0035] Figure 9 for Figure 5 The diagram shows a structural schematic of the cover plate assembly from the bottom view.

[0036] Explanation of reference numerals in the attached figures:

[0037] 1. Valve body; 110. Welding area; 111. First side; 120. Thinning area; 121. First surface; 2. Score; 201. Semicircular area; 202. Rectangular area; 3. Recess; 4. Connecting section; 5. Cover plate body; 501. Explosion-proof valve hole; 502. Explosion-proof groove; 6. Plastic part; 601. Relief part; 7. Pole post. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0039] The explosion-proof valve in the battery structure plays an important safety role. It serves as a controllable and directional venting window when high-temperature and high-pressure gases are present in an abnormal state inside the battery. The explosion-proof valve is usually constructed with grooves, and the grooves are the first points where the valve will break when it explodes. The relatively weak nature of the explosion-proof valve makes it susceptible to external forces, which can lead to occasional damage to the explosion-proof valve at the grooves during normal battery use. This can result in electrolyte leakage and ultimately render the entire battery pack unusable. Therefore, the explosion-proof valve also needs to be reinforced.

[0040] The following is combined with Figures 1 to 9 The following describes embodiments of the present invention.

[0041] According to an embodiment of the present invention, in one aspect, an explosion-proof valve is provided, such as... Figures 1 to 4 As shown, the explosion-proof valve includes: a valve body 1, a notch 2, and a recess 3. The valve body 1 includes a welding area 110 and a thinning area 120. The welding area 110 surrounds the outer periphery of the thinning area 120, and the thickness of the thinning area 120 is less than the thickness of the welding area 110. The valve body 1 has a length dimension of A. The notch 2 is formed in the thinning area 120, and its orthographic projection onto the surface of the valve body 1 is at least annular. The recess 3 is located within the inner annular region of the notch 2 and at the center of the thinning area 120. The recess 3 is formed by a portion of the first surface 121 of the thinning area 120 recessed in a direction away from the first surface 121. The recess 3 has a length dimension of C along the length of the valve body 1, where C and A satisfy the relationship: 1 / 3 ≤ C / A ≤ 1 / 2. Here, the length direction refers to... Figure 2 The middle arrow points to the "length direction"; thickness refers to the length along the length. Figure 3The dimension in the "up and down" direction indicated by the middle arrow; the outer periphery of the thinning zone 120 refers to the side of the circumferential edge of the thinning zone 120 that is far from the center of the thinning zone 120.

[0042] The explosion-proof valve of this embodiment uses a recessed portion 3 within the inner ring region of the annular area where the groove 2 is located on the thinning area 120. This means that an inner reinforcing rib is added to the middle of the explosion-proof valve. The recessed portion 3 also reduces the stress formed on the thinning area 120 during the processing and forming process, thereby reducing the stress on the groove 2 and effectively preventing the groove 2 from breaking under normal battery operation. This effectively increases the overall strength of the explosion-proof valve, thereby improving battery safety. Furthermore, by setting the dimension C of the recessed portion 3 along the length direction of the valve body 1 to satisfy the relationship 1 / 3≤C / A≤1 / 2, the recessed portion 3 has a reasonable dimension in the length direction. This avoids the recessed portion 3 being too small relative to the length of the valve body 1, which would not effectively strengthen the structural strength of the explosion-proof valve. At the same time, it avoids the recessed portion 3 being too close to the groove 2, which would affect the groove 2, thereby further increasing the structural strength of the explosion-proof valve.

[0043] If C / A is less than 1 / 3, the dimension of the recessed portion 3 along its length is too small relative to the valve body 1, and the effect of the recessed portion 3 on the thinning zone 120 is not obvious, failing to effectively strengthen the structure of the explosion-proof valve. If C / A is greater than 1 / 2, the dimension of the recessed portion 3 along its length is too large relative to the valve body 1, and the two sides of the recessed portion 3 along its length are too close to the notch 2, which may damage the notch 2 during processing, also hindering the improvement of the explosion-proof valve's structural strength. Both C and A are in mm.

[0044] It should be noted that the valve body 1 includes a welding area 110 and a thinning area 120, and the thickness of the thinning area 120 is less than the thickness of the welding area 110. The welding area 110 is used for welding with the cover plate body 5, and the structural strength of the thinning area 120 is less than the structural strength of the welding area 110. The orthographic projection of the groove 2 on the surface of the valve body 1 is annular or C-shaped, i.e., an annular portion.

[0045] Preferably, the recess 3 is centrally located on the valve body 1 along the length direction. Along the length direction, the distance from the first side edge of the recess 3 to the first side edge of the valve body 1 is B, and the distance from the second side edge of the recess 3 to the second side edge of the valve body 1 is D. Then B = D, which ensures the symmetry of the structure on the valve body 1, so that the force is uniform and the reliability is high.

[0046] In one embodiment, the thinning region 120 has a dimension E along the width direction of the valve body 1, and the recess 3 has a dimension F along the width direction of the valve body 1, wherein F and E satisfy the relationship: 1 / 4 ≤ F / E ≤ 1 / 3. Here, the width direction refers to... Figure 3The "width direction" indicated by the middle arrow is perpendicular to the length direction; the units of F and E are both mm. The recess 3 is located within the thinning zone 120. If F / E is less than 1 / 4, the dimension of the recess 3 along the width direction is too small relative to the dimension of the thinning zone 120 along the width direction, and the effect of the recess 3 along the width direction on the thinning zone 120 is not significant, failing to effectively reduce stress. If F / E is greater than 1 / 3, the dimension of the recess 3 along the width direction is too large relative to the dimension of the thinning zone 120 along the width direction, and the two sides of the recess 3 along the width direction are too close to the notch 2, potentially damaging the notch 2 during processing, which is also detrimental to improving the structural strength of the explosion-proof valve.

[0047] Therefore, by setting the dimension E of the thinning zone 120 along the width direction of the valve body 1 and the dimension F of the recess 3 along the width direction of the valve body 1 to satisfy the relationship 1 / 4≤F / E≤1 / 3, the recess 3 has a reasonable dimension along the width direction. This ensures that the recess 3 strengthens the structural strength of the thinning zone 120 while avoiding damage to the groove 2, thus ensuring the strengthening effect of the recess 3 on the overall structural strength of the explosion-proof valve.

[0048] Optionally, further integration Figure 2 As shown, the MM section is a section parallel to the width direction of the valve body 1 and perpendicular to the first side 111 of the valve body 1. The orthographic projection of the recessed part 3 on this section can be trapezoidal or semi-circular, with a simple structure and easy processing. The recessed part 3 is generally elongated, adapting to the shape of the valve body 1.

[0049] In one embodiment, the thinning region 120 is an arc-shaped surface that protrudes from the second side of the valve body 1 toward the first side of the valve body 1. The first side refers to... Figure 3 The first side, indicated by the middle arrow, is the direction of "up". The second side refers to the direction along... Figure 3 The side indicated by the middle arrow pointing "down" is the side facing outwards from the battery casing when the explosion-proof valve is installed on the battery. The second side faces inwards from the battery casing. By setting the thinning area 120 as a smooth arc surface, and the arc surface protruding from the second side of the valve body 1 towards the first side of the valve body 1, when the explosion-proof valve is installed on the battery, the arc surface protrudes from the side of the valve body 1 facing inwards from the battery casing to the outside of the casing. The high-pressure gas generated by the battery due to an anomaly acts on the concave surface of the arc surface, which helps the gas to break through the explosion-proof valve, ensuring the smooth opening of the explosion-proof valve and thus improving the safety of the battery.

[0050] Preferably, the highest point of the arc-shaped surface is flush with the plane containing the first side surface 111 of the welding area 110.

[0051] In one embodiment, the recessed depth of the recessed portion 3 relative to the first side surface 111 of the welding area 110 is H0, wherein 0.5mm ≤ H0 ≤ 1.2mm. Further combined with... Figure 3 and Figure 7 As shown, the explosion-proof valve is mounted on the cover plate body 5. The recessed part 3 is recessed downwards, that is, towards the direction of the plastic part 6. If H0 is greater than 1.2mm, the recessed depth of the recessed part 3 is too large, posing a risk of interference with the plastic part 6; if H0 is less than 0.5mm, the recessed depth of the recessed part 3 is too small, and the effect of strengthening the structural strength of the explosion-proof valve is not significant. Therefore, by setting the recessed depth H0 of the recessed part 3 relative to the first side 111 of the welding area 110 to a value within the range of 0.5mm to 1.2mm, it is possible to ensure that the recessed part 3 has sufficient depth to strengthen the structural strength of the explosion-proof valve, while avoiding excessive recessed depth that could interfere with the plastic part 6, thereby improving the overall safety of the battery. Here, "downwards" refers to the direction towards... Figure 3 and Figure 7 The direction indicated by the middle arrow is "down".

[0052] In one embodiment, the thickness of the thinning region 120 is H1, where 0.15mm ≤ H1 ≤ 0.18mm. It should be noted that the thinning region 120 is an arc-shaped surface; therefore, the thickness of the thinning region 120 refers to the wall thickness of the sphere containing the arc-shaped surface. If H1 is less than 0.15mm, the thickness of the thinning region 120 is insufficient, resulting in insufficient structural strength and a tendency to rupture before reaching the explosion condition, which is detrimental to battery safety. If H1 is greater than 0.18mm, the thickness of the thinning region 120 is too large, increasing the difficulty of explosion. When the gas pressure inside the battery reaches the explosion condition, the explosion-proof valve may not explode in time, posing a significant danger. Therefore, by setting the thickness H1 of the thinning region 120 within the range of 0.15mm to 0.18mm, the thinning region 120 has a reasonable thickness, ensuring both sufficient structural strength and timely explosion-proof valve explosion, thereby guaranteeing battery safety.

[0053] In one embodiment, the thickness of the welding area 110 is H2, where 0.45mm ≤ H2 ≤ 0.55mm. If H2 is less than 0.45mm, the thickness of the welding area 110 is too small, resulting in insufficient structural strength and easy damage during welding between the welding area 110 and the cover plate body 5, leading to poor welding quality. If H2 is greater than 0.55mm, the thickness of the welding area 110 is too large, requiring excessive material and increasing weight. It may also protrude from the surface of the cover plate body 5, occupying space inside the battery for the electrode assembly, which is detrimental to improving the volumetric energy density of the battery. Therefore, by setting the thickness H2 of the welding area 110 within the range of 0.45mm to 0.55mm, it is possible to ensure that the welding area 110 has sufficient structural strength and welding quality between the welding area 110 and the cover plate body 5, while avoiding excessive weight due to excessive thickness of the welding area 110, thereby reducing costs and preventing the explosion-proof valve from occupying too much space inside the battery, thus improving the volumetric energy density of the battery.

[0054] In one embodiment, the shortest distance from the outer edge of the notch 2 to the outer peripheral edge of the thinning region 120 is W, where 0.45mm ≤ W ≤ 0.5mm. It should be noted that the explosion-proof valve breaks along the notch 2 upon explosion. The notch 2 is used to control the detonation value. The area enclosed by the ring containing the notch 2 is the detonation reversal region, which is a smooth, curved surface. The notch 2 is groove-shaped, surrounding the center of the thinning region 120. The outer edge of the notch 2 refers to the location of the sidewall on the side of the groove furthest from the center of the thinning region 120. The outer peripheral edge of the thinning region 120 connects to the inner peripheral surface of the welding region 110, which is annular. W is the vertical distance from the outer edge of the notch 2 to the inner peripheral surface of the welding region 110. If W is less than 0.45mm, then... The distance from the outer edge of the notch 2 to the outer periphery of the thinning area 120 is too short, which is not conducive to the processing and shaping of the notch 2. Furthermore, the notch 2 is too close to the welding area 110, which is not conducive to the notch 2 breaking when the gas pressure inside the battery reaches the explosion condition. If W is greater than 0.5mm, the distance from the outer edge of the notch 2 to the outer periphery of the thinning area 120 is too large. After the notch 2 breaks, the area enclosed by the notch 2 opens up as an actual exhaust channel. The exhaust area of ​​the actual exhaust channel is too different from the total area of ​​the thinning area 120, which is not conducive to the full utilization of the explosion-proof valve. There is a situation of insufficient exhaust area, which is not conducive to the timely discharge of gas.

[0055] Therefore, by setting the shortest distance W from the outer edge of the notch 2 to the outer peripheral edge of the thinning zone 120 to be within the range of 0.45mm to 0.5mm, it is possible to ensure that the notch 2 can be smoothly processed and formed, and that the notch 2 can break in time when the gas pressure inside the battery reaches the explosion condition. It is also possible to ensure that the actual venting area enclosed by the notch 2 has sufficient venting area, so as to ensure that the gas inside the battery can be smoothly discharged when the explosion-proof valve is opened, thereby improving the safety of the battery.

[0056] In one embodiment, the thinning region 120 further includes a connecting segment 4, which is connected end-to-end to the notch 2 to surround the valve body 1. The area enclosed by the notch 2 and the connecting segment 4 is oblong. Further integration Figure 2 As shown, the connecting segment 4 and the notch 2 are connected end to end to form a closed ring. The connecting segment 4 is the part of the thinning area 120 without the notch 2. Therefore, the strength of the connecting segment 4 is greater than the strength of the notch 2. When the gas pressure in the notch 2 inside the battery reaches the preset pressure value and breaks, the connecting segment 4 will not break. This can prevent the thinning area 120 from bursting open and causing secondary damage to the surrounding battery or other structures, thereby reducing the risk.

[0057] In one embodiment, the orthographic projection of the recess 3 onto the plane of the upper surface of the valve body 1 is an elongated circle, which has a simple structure, is easy to process, and has a smooth transition around the perimeter, which can reduce stress concentration.

[0058] In one embodiment, further combination Figure 2 As shown, the oblong shape includes semicircular regions 201 located on both sides along its length and a rectangular region 202 located between the two semicircular regions 201. The dimension of the rectangular region 202 along the length of the valve body 1 is L, where 1 / 2 < C / L < 1. It should be noted that the length direction refers to the direction along the length of the valve body 1. Figure 2 The "length direction" indicated by the middle arrow refers to the length direction of the valve body 1. The first long side of the rectangle formed by the rectangular area 202 is completely covered by the groove 2. Part of the second long side is covered by the groove 2, and the other part is the connecting section 4. The first long side and the second long side are two opposite long sides of the rectangular area 202. The groove depth of the section on the groove 2 corresponding to the first long side is greater than the groove depth of other sections on the groove 2. The section on the groove 2 corresponding to the first long side is the section that breaks first when the explosion-proof valve explodes. The structural strength at this position is easily affected by external forces, such as the restraint forces on both sides, the stress of the battery cell, and internal or external pressure. It is easy to break and crack, resulting in electrolyte leakage and battery cell failure. Therefore, it is necessary to set a recessed part 3 corresponding to the first long side to strengthen the strength at this position.

[0059] By setting the dimension C of the recessed portion 3 along the length direction of the valve body 1 and the dimension L of the rectangular area 202 along the length direction of the valve body 1 to satisfy the relationship 1 / 2 < C / L < 1, the recessed portion 3 is located within the rectangular area 202. This ensures that the dimension of the recessed portion 3 in the length direction has a sufficient proportion to the dimension of the rectangular area 202, thereby ensuring the reinforcing effect of the recessed portion 3 on the structural strength of the explosion-proof valve. At the same time, it prevents the recessed portion 3 from exceeding the rectangular area 202 and reaching the semicircular areas 201 on both sides, which would cause the recessed portion 3 to be too close to the section of the notch 2 corresponding to the semicircular area 201 and affect the structural strength of that part, thereby improving safety.

[0060] It should be noted that, through modeling and simulation of the explosion-proof valve in this embodiment, simulation data shows that when the dimension C of the recessed portion 3 along the length direction of the valve body 1 and the dimension L of the rectangular area 202 along the length direction of the valve body 1 satisfy the relationship 1 / 2 < C / L < 1, the overall stress of the explosion-proof valve is reduced by 12%-15%, which can effectively improve the overall strength of the explosion-proof valve.

[0061] In this embodiment, the explosion-proof valve has a recessed part 3 in the middle of the valve body 1 as an inner reinforcing rib, which effectively enhances the structural strength of the explosion-proof valve. It provides structural reinforcement for weaker areas, reduces the risk of stress damage and leakage to the explosion-proof valve during the battery cell manufacturing process and safe use, and improves the quality of the product.

[0062] According to an embodiment of the present invention, another aspect also provides a cover plate assembly, such as... Figures 5 to 9 As shown, the cover plate assembly includes: a cover plate body 5 and the aforementioned explosion-proof valve. The cover plate body 5 has an explosion-proof valve hole 501; the explosion-proof valve is installed in the explosion-proof valve hole 501.

[0063] In one embodiment, further combination Figure 7 As shown, an explosion-proof groove 502 is provided on the cover plate body 5. The explosion-proof groove 502 is formed by a portion of the lower surface of the cover plate body 5 recessed towards the upper surface of the cover plate body 5. An explosion-proof valve hole 501 is formed in the explosion-proof groove 502. The explosion-proof valve hole 501 is a through hole that penetrates the cover plate body 5 in the vertical direction. The welding area 110 of the explosion-proof valve is located in the explosion-proof groove 502 and is welded to the surface of the explosion-proof groove 502. Here, the lower surface refers to... Figure 7 The surface indicated by the middle arrow pointing "down" refers to the upper surface. Figure 7 The surface in the direction indicated by the middle arrow, which points to "up".

[0064] It should be noted that the lower surface of the recessed portion 3 is lower than the lower surface of the welding area 110. Preferably, the lower surface of the welding area 110 is flush with the lower surface of the cover plate body 5, in which case the lower surface of the recessed portion 3 is lower than the lower surface of the cover plate body 5.

[0065] In one embodiment, the cover assembly further includes a plastic part 6 disposed on the lower side of the cover body 5. The plastic part 6 has a recessed portion 601 formed by a portion of the upper surface of the plastic part 6. The recessed portion 601 corresponds to the recessed portion 3 of the explosion-proof valve. The upper surface of the recessed portion 601 and the lower surface of the recessed portion 3 are spaced apart, with a distance of H3 between them, where 0.4mm ≤ H3 ≤ 0.6mm. Here, "lower side" refers to... Figure 7The side indicated by the middle arrow pointing "down". By providing a plastic part 6 on the lower side of the cover plate body 5, the plastic part 6 separates the cover plate body 5 from the electrode assembly, ensuring insulation between the cover plate body 5 and the electrode assembly body. Furthermore, by providing a clearance portion 601 corresponding to the recessed portion 3 on the explosion-proof valve on the side of the plastic part 6 facing the cover plate body 5, the clearance portion 601 provides clearance space for the recessed portion 3, preventing the recessed portion 3 from being squeezed against the plastic part 6, thus avoiding affecting the assembly of the plastic part 6 on the cover plate body 5 or causing damage to the component. Simultaneously, by providing a clearance portion 601 with its upper surface spaced apart from the lower surface of the recessed portion 3, and with the clearance portion 601 positioned between them... The distance H3 is taken within the range of 0.4mm to 0.6mm. This ensures that there is sufficient vertical spacing between the lower surface of the recessed part 3 and the plastic part 6, thus avoiding interference between the recessed part 3 and the plastic part 6. At the same time, it also avoids that the vertical spacing between the lower surface of the recessed part 3 and the plastic part 6 is too large, which would result in an excessively large recess size of the relief part 601 in the vertical direction. This also avoids that the thickness of the solid part on the plastic part 6 corresponding to the relief part 601 in the vertical direction is too small, thus ensuring that the plastic part 6 has sufficient structural strength and further improving the safety of the battery.

[0066] In one embodiment, the cover assembly further includes a terminal post 7, which passes through the cover body 5 and is used for electrical connection with the electrode group inside the battery. An insulating element and a sealing ring are also provided between the terminal post 7 and the cover body 5 to achieve insulation and sealing between the terminal post 7 and the cover body 5.

[0067] According to an embodiment of the present invention, another aspect provides a battery, comprising: a housing, an electrode assembly, and the aforementioned cover assembly. The housing has an open end; the electrode assembly is placed inside the housing; the cover assembly is disposed on the open end of the housing to close the housing.

[0068] Optionally, the battery is a lithium battery.

[0069] Although 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 all fall within the scope defined by the appended claims.

Claims

1. An explosion-proof valve, characterized in that, include: The valve body includes a welding area and a thinning area. The welding area is connected to the outer periphery of the thinning area. The thickness of the thinning area is less than the thickness of the welding area. The dimension of the valve body along its length is A. A notch is formed in the thinned area, and the orthographic projection of the notch onto the surface of the valve body is at least annular. A recessed portion is provided within the inner ring region of the annular ring where the groove is located and at the center of the thinning region. The recessed portion is formed by a portion of the first surface of the thinning region being recessed in a direction away from the first surface. The dimension of the recessed portion along the length direction of the valve body is C, wherein C and A satisfy the relationship: 1 / 3≤C / A≤1 / 2.

2. The explosion-proof valve according to claim 1, characterized in that, The dimension of the thinning zone along the width direction of the valve body is E, and the dimension of the recess along the width direction of the valve body is F, wherein F and E satisfy the relationship: 1 / 4≤F / E≤1 / 3.

3. The explosion-proof valve according to claim 1, characterized in that, The thinning area is an arc-shaped surface that protrudes from the second side of the valve body toward the first side of the valve body.

4. The explosion-proof valve according to claim 3, characterized in that, The recessed depth of the recessed portion relative to the first side of the welding area is H0, wherein 0.5mm≤H0≤1.2mm.

5. The explosion-proof valve according to claim 1, characterized in that, The thickness of the thinning region is H1, wherein 0.15mm ≤ H1 ≤ 0.18mm; And / or, the thickness of the welded area is H2, wherein 0.45mm ≤ H2 ≤ 0.55mm; And / or, the shortest distance from the outer edge of the notch to the outer peripheral edge of the thinning area is W, where 0.45mm≤W≤0.5mm.

6. The explosion-proof valve according to any one of claims 1 to 5, characterized in that, The thinning zone also includes a connecting segment, the thickness of which is equal to the thickness of the thinning zone. The connecting segment is connected end to end to the groove to surround the valve body. The area enclosed by the groove and the connecting segment is oblong.

7. The explosion-proof valve according to claim 6, characterized in that, The oblong shape includes semicircular regions on both sides of the length direction and a rectangular region between the two semicircular regions. The rectangular region has a dimension L along the length direction of the valve body, where 1 / 2 < C / L < 1.

8. A cover plate assembly, characterized in that, include: The cover plate body has an explosion-proof valve hole constructed on it; The explosion-proof valve according to any one of claims 1 to 7, wherein the explosion-proof valve is installed in the explosion-proof valve orifice.

9. The cover plate assembly according to claim 8, characterized in that, The cover plate assembly further includes: a plastic part disposed on the lower side of the cover plate body, the plastic part having a clearance portion formed by a recessed area of ​​the upper surface of the plastic part, the clearance portion corresponding to the recessed portion of the explosion-proof valve, the upper surface of the clearance portion and the lower surface of the recessed portion being spaced apart and the distance between them being H3, wherein 0.4mm≤H3≤0.6mm.

10. A battery, characterized in that, include: The shell has an open end; The electrode assembly is placed inside the housing; The cover assembly of claim 9 is disposed over the open end of the housing to close the housing.

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