Explosion-proof valve and battery top cover

Abstract

The utility model discloses an anti-explosion valve. An anti-explosion valve body is of an integrally-formed runway-shaped sheet structure. The main body comprises an edge boss protruding outwards along the edge of the back face and an anti-explosion valve plate located on the inner side of the edge boss. The inner wall of the edge boss is composed of a first bevel edge, a straight edge and a second bevel edge which are sequentially connected. The back face of the body is provided with a turnover groove facilitating explosion of the anti-explosion valve block during explosion. The folding groove is located between the anti-explosion valve plate and the edge boss. And the front surface of the anti-explosion valve plate is provided with a blasting line which is convenient for the anti-explosion valve plate to be divided into a plurality of explosion flaps to burst and tilt during blasting. The explosion-proof valve is good in explosion consistency and reliability, the explosion line is far away from the edge, and heat influence is small during welding; the space required for unfolding the explosion-proof valve plate is small, so that the arrangement of a more compact battery system is facilitated; according to the explosion-proof valve welding boss, the strength of the explosion-proof valve hole is enhanced while the top cover base plate is not thinned, the influence of external stress on the explosion-proof valve is reduced, and corrosion of the explosion-proof valve caused by the fact that electrolyte is accumulated at the position of the valve hole during liquid injection can be prevented.

Description

Technical Field

[0001] This utility model belongs to the field of secondary battery technology, specifically relating to an explosion-proof valve. Background Technology

[0002] The explosion-proof valve on the top cover of a lithium-ion battery is a key component in battery safety design. Its main function is to prevent battery explosion by releasing pressure when the internal pressure of the battery becomes too high, thereby protecting the safety of users and equipment. The explosion-proof valve is generally located on the top cover of the battery, a specially designed vulnerable area. When the internal pressure of the battery reaches a certain value, the explosion-proof valve automatically opens to release the pressure. When a lithium-ion battery operates under abnormal conditions (such as overcharging, short circuit, or high temperature), a large amount of gas is generated inside the battery, causing the internal pressure to rise rapidly. The explosion-proof valve is designed with an opening threshold based on the battery's maximum permissible pressure. Once this pressure is exceeded, the valve automatically opens to release the internal gas, preventing further pressure accumulation. By releasing pressure in a timely manner, the explosion-proof valve can effectively avoid the risk of battery explosion. If the pressure cannot be released, the battery casing may rupture or even explode, leading to fire or personal injury. The explosion-proof valve is designed to provide a safe exit in such extreme situations. Currently, the explosion-proof valve on the battery top cover is typically made of a single layer of membrane-shaped aluminum sheet. The material thickness is precisely calculated. The opening principle of a mechanical explosion-proof valve relies on the deformation and rupture of the material under specific pressure to release internal pressure. During the design phase, appropriate shapes, materials, and thicknesses are selected to ensure that the explosion-proof valve can reliably open under a predetermined pressure. This type of explosion-proof valve has grooves around the valve plate. By controlling the residual thickness and width of the grooves, as well as the annealing treatment after manufacturing, it is ensured that rupture will occur first under the predetermined pressure, thereby opening the valve plate and releasing the internal pressure of the battery.

[0003] The inventors discovered the following problems with existing explosion-proof valves: The "breathing effect" caused by changes in battery cell charging and discharging, as well as gas pressure and temperature, leads to stress accumulation at weak structural grooves. The stress accumulation varies at different locations along the edge of the valve body, making areas with higher stress prone to fracture. Existing explosion-proof valves have uniform grooves along the valve edge, which easily cause stress concentration. This results in the valve rupturing before the battery cell's internal pressure reaches the pressure relief valve's burst value, compromising the battery cell's seal and causing premature failure. Existing explosion-proof valves... The valve grooves are set along the shape of the explosion-proof valve and are close to the edge. When the explosion-proof valve is welded to the top cover, the high temperature generated by laser welding will cause thermal stress to be conducted to the grooves, causing stress concentration at the grooves and reducing the opening pressure of the explosion-proof valve. When the battery cells are assembled and used, the grooves are easily affected by external forces because they are close to the edge of the valve body, which reduces the reliability of the explosion-proof valve. When the top cover accommodates the explosion-proof valve, a part of the space is usually cut off from the top cover base plate. This reduces the strength of the explosion-proof valve hole on the base plate, making the explosion-proof valve more susceptible to external stress. Summary of the Invention

[0004] The purpose of this invention is to provide an explosion-proof valve to solve the above-mentioned problems of existing explosion-proof valves.

[0005] The technical solution of this utility model is as follows: an explosion-proof valve, the main body of which is an integrally formed racetrack-shaped sheet structure; the main body includes an edge boss protruding outward along the back edge and an explosion-proof valve sheet located inside the edge boss;

[0006] The inner wall of the edge boss is composed of a first inclined side, a straight side, and a second inclined side connected in sequence;

[0007] The back of the main body is provided with a folding groove to facilitate the explosion of the explosion-proof valve plate when it explodes; the folding groove is located between the explosion-proof valve plate and the edge boss;

[0008] The front of the explosion-proof valve plate is provided with a blast line that facilitates the explosion-proof valve plate to split into multiple explosive petals and pop up during explosion.

[0009] The outer edge of the edge boss is racetrack-shaped, and the inner edge is polygonal; the folding groove is polygonal.

[0010] The explosion petal is an acute-angled triangular explosion petal or a trapezoidal explosion petal.

[0011] When an explosion-proof valve explodes, the height of each explosion flap on the valve plate is less than half the width Wv of the valve body.

[0012] The rupture line consists of multiple straight grooves extending inward from the edge boss and converging inside the valve plate.

[0013] The blasting line includes a main blasting line located in the middle of the explosion-proof valve plate and parallel to the long side of the main body, and multiple secondary blasting lines connected to the main blasting line.

[0014] The thickness Td of the edge boss is 0.5-2mm; the thickness Tv of the explosion-proof valve plate is within 0.3mm; the depth Tg of the folding groove is 60%-80% of the thickness Tv of the explosion-proof valve plate; the groove width Wg of the folding groove is between 0.05-0.2mm; and the depth Tn of the rupture line is 30%-60% of the thickness Tv of the explosion-proof valve plate.

[0015] The thickness Td of the edge boss is 1 mm.

[0016] The present invention also provides a battery top cover, including a top cover substrate and an explosion-proof valve mounted on the top cover substrate; the explosion-proof valve is the aforementioned explosion-proof valve.

[0017] The top cover base plate is provided with an explosion-proof valve hole; the inner wall of the explosion-proof valve hole is provided with an explosion-proof valve mounting flange; the edge of the explosion-proof valve hole is provided with an explosion-proof valve welding boss protruding from the front side of the top cover base plate.

[0018] Compared with the prior art, the beneficial effects of this utility model are as follows: The explosion-proof valve provided by this utility model has a polygonal blast-thinning section, with the blast line extending inward from the edge. The explosion-proof valve plate is divided into multiple areas by the folding groove and the blast line, which split into multiple explosion petals that pop up during blasting. The explosion petals are acute-angled triangular or trapezoidal, which reduces the impact of the stress caused by breathing on the blast line and other weakened parts. At the same time, its resistance to external forces is better than that of traditional technology. This explosion-proof valve has better blast consistency and reliability. The blast line extends inward from the explosion-proof valve boss and converges inside the valve plate. It is far from the edge, so it is less affected by the heat during welding and less susceptible to the influence of assembly welding. When the explosion-proof valve explodes, the maximum height of each explosion flap is less than half the width of the explosion-proof valve. In contrast, the height of the valve plate after explosion of a traditional explosion-proof valve is equal to the width of the valve. The explosion-proof valve plate of this invention requires less space to unfold, which is conducive to a more compact battery system layout and avoids wasting height. The battery top cover accommodates the explosion-proof valve by designing an explosion-proof valve welding boss on the front. This strengthens the strength of the explosion-proof valve hole without thinning the top cover substrate, reducing the impact of external stress on the explosion-proof valve. The explosion-proof valve welding boss protruding at the explosion-proof valve hole of the top cover substrate and the explosion-proof valve welded on the front (without space to accommodate electrolyte) can prevent electrolyte from accumulating at the valve hole position during liquid injection, thus preventing corrosion of the explosion-proof valve. Attached Figure Description

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0020] Figure 1 This is a structural schematic diagram of the explosion-proof valve of this utility model.

[0021] Figure 2 This is a bottom view of the explosion-proof valve of this utility model.

[0022] Figure 3 This is the front view of the explosion-proof valve of this utility model.

[0023] Figure 4 This is a top view of the explosion-proof valve of this utility model.

[0024] Figure 5 yes Figure 4 AA sectional view.

[0025] Figure 6 This is a schematic diagram of the battery top cover.

[0026] Figure 7 This is the second schematic diagram of the battery top cover.

[0027] Figure 8 This is a schematic diagram of the top cover substrate.

[0028] Figure 9 This is a top view of the top cover substrate.

[0029] Figure 10 yes Figure 9 BB cross-sectional view.

[0030] Figure 11 This is a schematic diagram of the battery top cover after the explosion-proof valve ruptures.

[0031] Figure 12 yes Figure 11 Enlarged view of part I. Detailed Implementation

[0032] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present utility model or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0033] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0034] like Figures 1-3 As shown, the first aspect of this utility model provides an explosion-proof valve. The explosion-proof valve body 1 is an integrally formed sheet structure, which includes, from the outside to the inside, an edge boss 101, a first inclined side 102, a straight side 107, a second inclined side 103, a folded groove 104, and an explosion-proof valve plate 105. The explosion-proof valve plate 105 is provided with a rupture line 106.

[0035] The inner side of the edge boss 101 forms a polygon, and the folding groove 104 forms a through polygon with the inner edge of the inner wall of the edge boss 101 as the boundary.

[0036] The burst line 106 extends inward from the explosion-proof valve boss, converging inside the valve plate. It can converge at a single point or multiple points, and together with the folding groove 104, divides the explosion-proof valve plate 105 into multiple regions, minimizing the impact of stress changes caused by breathing effects (temperature changes, pressure changes, gas generation and absorption by the battery cell, and volume changes during battery cell charging and discharging). The burst line of the explosion-proof valve can be a stamping mark or a weakening structure created by laser, plasma, microwave beams, etc.

[0037] like Figure 4 As shown, the blasting line 106 includes a main blasting line 1061 located in the middle of the explosion-proof valve plate 105 and parallel to the long side of the main body 1, and multiple secondary blasting lines 1062 connected to the main blasting line 1061. The explosion-proof valve plate 105 is divided into multiple regions by the folding groove 104 and the blasting line 106, which split into multiple explosive petals that open and rise during blasting. The explosive petals can be acute-angled triangular explosive petals or trapezoidal explosive petals.

[0038] like Figure 5 As shown, the thickness Td of the edge boss 101 is controlled between 0.5-2mm, preferably 1mm; the thickness Tv of the explosion-proof valve plate 105 is controlled within 0.3mm; and the depth Tn of the blast line 106 is controlled at 30%-60% of the thickness Tv of the explosion-proof valve plate. The depth Tg of the folding groove 104 is controlled at 60%-80% of the thickness Tv of the explosion-proof valve plate, and the groove width Wg of the folding groove 104 is controlled between 0.05-0.2mm.

[0039] like Figures 6-10 As shown, this embodiment of the present invention also provides a battery top cover with the explosion-proof valve described in the first aspect installed. The battery top cover includes a top cover base plate 21 and an explosion-proof valve 1 mounted on the top cover base plate 21. The top cover base plate 21 is provided with an explosion-proof valve hole 201. An explosion-proof valve mounting flange 202 is provided on the inner wall of the explosion-proof valve hole 201. An explosion-proof valve welding boss 203 is provided on the edge of the explosion-proof valve hole 201, protruding from the front side of the top cover base plate 21. The explosion-proof valve welding boss 203 protrudes from the front side of the top cover base plate 21, which strengthens the strength of the explosion-proof valve hole and also prevents the electrolyte from seeping in during liquid injection.

[0040] like Figure 11 , Figure 12 As shown, the working process of this utility model is as follows: When the internal pressure of the battery cell is too high, the explosion-proof valve plate 105 opens by dividing into four acute-angled triangular explosion petals 1051 and two trapezoidal explosion petals 1052 from the rupture line position. Each explosion petal of the explosion-proof valve plate 105 rises from the folding groove 104 and releases pressure from the explosion-proof valve hole 201. When the explosion-proof valve explodes, the height of each explosion petal is only half the width Wv of the explosion-proof valve body 1, which improves the space utilization rate.

[0041] The above description is only an exemplary embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An explosion-proof valve, characterized in that: The explosion-proof valve body (1) is an integrally formed racetrack-shaped sheet structure; the body (1) includes an edge boss (101) protruding outward along the back edge and an explosion-proof valve plate (105) located inside the edge boss (101). The inner wall of the edge boss (101) is composed of a first inclined side (102), a straight side (107), and a second inclined side (103) connected in sequence; The back of the main body (1) is provided with a folding groove (104) to facilitate the explosion of the explosion-proof valve plate (105) when it explodes; the folding groove (104) is located between the explosion-proof valve plate (105) and the edge boss (101); The explosion-proof valve plate (105) has an explosion line (106) on its front side that facilitates the explosion-proof valve plate (105) to split into multiple explosion petals and pop up when it explodes.

2. The explosion-proof valve according to claim 1, characterized in that: The outer edge of the edge boss (101) is racetrack-shaped, and the inner edge is polygonal; the folding groove (104) is polygonal.

3. The explosion-proof valve according to claim 2, characterized in that: The explosion lobe is an acute-angled triangular explosion lobe (1051) or a trapezoidal explosion lobe (1052).

4. The explosion-proof valve according to claim 1, characterized in that: When the explosion-proof valve explodes, the height of each explosion petal of the explosion-proof valve plate (105) is less than half the width Wv of the explosion-proof valve body (1).

5. The explosion-proof valve according to claim 1, characterized in that: The blast line (106) is a series of straight grooves that extend inward from the edge boss (101) and converge inside the valve plate.

6. The explosion-proof valve according to claim 1, characterized in that: The blasting line (106) includes a main blasting line (1061) located in the middle of the explosion-proof valve plate (105) and parallel to the long side of the main body (1), and multiple secondary blasting lines (1062) connected to the main blasting line (1061).

7. The explosion-proof valve according to claim 1, characterized in that: The thickness Td of the edge boss (101) is 0.5-2mm; the thickness Tv of the explosion-proof valve plate (105) is within 0.3mm; the depth Tg of the folding groove (104) is 60%-80% of the thickness Tv of the explosion-proof valve plate; the groove width Wg of the folding groove (104) is between 0.05-0.2mm; and the depth Tn of the rupture line is 30%-60% of the thickness Tv of the explosion-proof valve plate.

8. The explosion-proof valve according to claim 7, characterized in that: The thickness Td of the edge boss (101) is 1 mm.

9. A battery top cover, comprising a top cover substrate (21) and an explosion-proof valve (1) mounted on the top cover substrate (21); characterized in that: The explosion-proof valve is the explosion-proof valve according to any one of claims 1 to 8.

10. The battery top cover according to claim 9, characterized in that: The top cover base plate (21) is provided with an explosion-proof valve hole (201); the inner wall of the explosion-proof valve hole (201) is provided with an explosion-proof valve mounting flange (202); the edge of the explosion-proof valve hole (201) is provided with an explosion-proof valve welding boss (203) protruding from the front of the top cover base plate (21).

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