Explosion-proof valve

Abstract

This explosion-proof valve comprises: an attachment member which is attached to a housing having a through-hole provided in a side wall part thereof and which is disposed on the outside of the through-hole; a cover which covers the through-hole; a plurality of plate springs which are disposed between the cover and the attachment member and fixed to the attachment member and the cover, and each of which has a first end and a second end; and a fixing member which fixes the plurality of plate springs to the cover. Each of the plurality of plate springs is displaced by means of the pressure inside the housing so that the cover is separated from the attachment member. The attachment member comprises a polygonal-shaped metallic frame and a frame-shaped seal fixed to the frame. The cover comprises a polygonal-shaped cover body and a shaft part protruding toward the through-hole from the center of the cover body. The frame comprises a support part which supports one end of each of the plurality of plate springs. The shaft part has a step surface. The fixing member has an insertion hole into which the shaft part is inserted, and, together with the step surface, sandwiches the other end of each of the plurality of plate springs to thereby fix the plurality of plate springs to the cover.

Description

Explosion-proof valve

[0001] The present disclosure relates to explosion-proof valves.

[0002] In recent years, the development of electric vehicles has accelerated, leading to increased safety requirements for the battery packs installed in these vehicles. Lithium-ion batteries, in particular, pose a high risk of ignition and fire. For this reason, explosion-proof valves are installed to release internal pressure in the battery pack in the event of an abnormality. Known explosion-proof valves include those using umbrella valves and those using coil springs. These valves are used according to their normal ventilation function, required valve opening pressure, and discharge performance in the event of an abnormality.

[0003] Patent Document 1 discloses a vent member. The vent member includes a vent valve serving as an umbrella valve and a structural member that supports the vent valve and is attached to a battery pack. The vent valve is provided so as to overlap a through-hole provided in the battery pack. When the difference between the internal pressure and the external pressure of the battery pack increases to a predetermined pressure or more, the vent valve opens and a large amount of gas is discharged in a short period of time. This discharge relieves the internal pressure.

[0004] International Publication No. 2020 / 085210

[0005] Explosion-proof valves are often placed on the side of a battery pack. If the height direction is limited by a low-height design, the size of the battery pack will become too small, making it impossible to obtain the required discharge performance. To solve this problem, it is possible to install multiple explosion-proof valves. However, installing multiple explosion-proof valves increases costs, which is undesirable. For this reason, one possible solution to the height restriction on battery packs is to install explosion-proof valves with a longitudinal shape along the side of the battery pack, i.e., a horizontally long, flat shape.

[0006] In the case of an explosion-proof valve with a horizontally elongated planar shape, compared to the circular planar shape of Patent Document 1, if the vent valve rotates relative to the structural member after opening and returning, the vent valve may not adequately seal the through-hole. In this case, the vent valve may not be able to block the inflow of oxygen. As a result, there is a risk of re-ignition. For this reason, in explosion-proof valves with a planar shape other than a circular shape, it is desirable to provide a strict anti-rotation mechanism to control the rotation of the explosion-proof valve before and after opening.

[0007] In order to solve the above problems, an explosion-proof valve according to one aspect of the present disclosure includes: a mounting member that is attached to a housing having a through hole in a side wall portion and that is arranged outside the through hole in a plan view of the through hole; a cover that is arranged on the opposite side of the mounting member from the housing and that covers the through hole; a plurality of leaf springs that are arranged between the cover and the mounting member and that are fixed to the mounting member and the cover, each of the plurality of leaf springs having a first end and a second end; and a fixing member that fixes the plurality of leaf springs to the cover, wherein each of the plurality of leaf springs is displaced by pressure inside the housing so as to separate the cover from the mounting member. The mounting member comprises a polygonal metal frame and a frame-shaped seal fixed to the frame, the cover comprises a polygonal cover body that seals the through hole when the seal abuts against it, and a shaft portion that protrudes from the center of the cover body toward the through hole, the frame of the mounting member comprises a support portion that supports each first end of the multiple leaf springs, the shaft portion of the cover has a stepped surface, and the fixing member has an insertion hole through which the shaft portion is inserted, and with the shaft portion inserted into the insertion hole, the multiple leaf springs are fixed to the cover by clamping each second end of the multiple leaf springs between the fixing member and the stepped surface.

[0008] According to the present disclosure, rotation of the cover relative to the mounting member before and after opening the cover can be suppressed.

[0009] 5 is a schematic diagram showing a battery pack to which the explosion-proof valve of the present embodiment is attached. FIG. 1 is a perspective view of the explosion-proof valve shown in FIG. 1. FIG. 2 is an exploded perspective view of the explosion-proof valve shown in FIG. 2. FIG. 3 is a top view of the explosion-proof valve shown in FIG. 2. FIG. 4 is a cross-sectional view taken along line A1-A1 in FIG. 4. FIG. 5 is a cross-sectional view taken along line A2-A2 in FIG. 4. FIG. 6 is a bottom view of the explosion-proof valve shown in FIG. 2. FIG. 5 is a cross-sectional view of the fixing portion, spring portion, and step surface shown in FIG. 5. FIG. 5 is a view showing a state in which the cover shown in FIG. 5 is separated from the mounting member. FIG. 6 is a view showing a state in which the cover shown in FIG. 6 is separated from the mounting member. FIG. 4 is an enlarged view showing the first protrusion and the second protrusion shown in FIG. 4. FIG. 4 is an enlarged view showing a state in which the second protrusion abuts against the first protrusion shown in FIG. 4.

[0010] Preferred embodiments of the present disclosure will be described below with reference to the accompanying drawings. Note that the dimensions or scale of each part in the drawings may differ from the actual dimensions, and some parts are shown schematically to facilitate understanding. Furthermore, the scope of the present disclosure is not limited to the following forms unless otherwise specified in the following description.

[0011] The following description will use the mutually intersecting X-axis, Y-axis, and Z-axis as appropriate. One direction along the X-axis is called the X1 direction, and the direction opposite to the X1 direction is called the X2 direction. Opposite directions along the Y-axis are called the Y1 direction and the Y2 direction. Opposite directions along the Z-axis are called the Z1 direction and the Z2 direction. Viewing in the direction along the Z-axis is called "planar view."

[0012] 1 is a schematic diagram showing a battery pack 900 to which an explosion-proof valve 100 according to the present embodiment is attached. The explosion-proof valve 100 according to the present embodiment is a safety valve provided to release internal air to reduce the internal pressure of the battery pack 900 if the internal pressure of the battery pack 900 becomes abnormally high.

[0013] The battery pack 900 shown in FIG. 1 is used in fields such as electronic devices and electric vehicles, and includes a secondary battery such as a lithium battery.

[0014] In the example shown in FIG. 1 , the battery pack 900 has a housing 90 that houses batteries such as lithium batteries. The housing 90 is a thin storage member. In the example shown, the housing 90 has a rectangular planar shape. The housing 90 also has sidewalls 92. The sidewalls 92 connect two rectangular flat plate portions that extend in the XY plane. The sidewalls 92 also have through-holes 92H for releasing pressure inside the housing 90. In this embodiment, the sidewalls 92 of the housing 90 have four sidewalls 921. The through-hole 92H is provided in one of the four sidewalls 921.

[0015] The side wall 921 also has a plurality of screw holes 921H. The plurality of screw holes 921H are provided outside the through-hole 92H. The plurality of screw holes 921H are provided for attaching the explosion-proof valve 100 to the housing 90. For example, each screw hole 921H is a female screw hole through which a screw (not shown) is inserted.

[0016] The shape of the battery pack 900 is not limited to the rectangular flat plate shape shown in FIG. 1, but may be any shape.

[0017] 1A. Explosion-proof Valve Figure 2 is a perspective view of the explosion-proof valve 100 shown in Figure 1. Figure 3 is an exploded perspective view of the explosion-proof valve 100 shown in Figure 2. Figure 4 is a top view of the explosion-proof valve 100 shown in Figure 2. Figure 5 is a cross-sectional view taken along line A1-A1 in Figure 4. Figure 6 is a cross-sectional view taken along line A2-A2 in Figure 4. Figure 7 is a bottom view of the explosion-proof valve 100 shown in Figure 2.

[0018] The explosion-proof valve 100 shown in Figures 2 to 7 includes a mounting member 2, a cover 3, a spring portion 4, and a fixing member 5. The cover 3 is in contact with the mounting member 2 or in a spaced-apart state due to the internal pressure of the housing 90. Figures 5 and 6 show the state in which the cover 3 is in contact with the mounting member 2. As shown in Figure 4, the explosion-proof valve 100 has an elongated shape with the longitudinal direction of the side wall 921 as its longitudinal direction.

[0019] 2 to 7 is a member for attaching the explosion-proof valve 100 to the housing 90. As shown in Fig. 3, the mounting member 2 is disposed outside the through-hole 92H in a plan view of the housing 90. The mounting member 2 has a frame 21, a seal 22, and a plurality of first protrusions 23.

[0020] The frame 21 is made of metal. Specifically, for example, the frame 21 is formed of stainless steel or the like. The frame 21 is polygonal, and in the illustrated example, is a square frame. Note that the polygonal frame shape is not limited to a strict polygonal frame shape, but includes shapes that can be considered to be polygonal frame shapes. The frame 21 also has a frame main body 211, a support portion 212, and a plurality of mounting protrusions 213.

[0021] The frame main body 211 is a rectangular frame-shaped portion along the XY plane. A support portion 212 is provided inside the frame main body 211. The support portion 212 is connected to the frame main body 211 and has an annular shape along the XY plane. The support portion 212 supports and fixes the spring portion 4.

[0022] In the illustrated example, the number of mounting protrusions 213 is six. The six mounting protrusions 213 are spaced apart from one another. Each mounting protrusion 213 protrudes outward from the frame body 211 along the X-Y plane. Each mounting protrusion 213 is provided with a through-hole 213H. The holes 213H are provided to correspond to the aforementioned screw holes 921H. Screws (not shown) are inserted into the holes 213H and then the screw holes 921H, thereby attaching the frame 21 to the housing 90. Note that the method of attaching the frame 21 to the housing 90 is not limited to screw fastening, and an attachment method using an adhesive or the like may also be used. However, screw fastening ensures stable fixation and heat resistance.

[0023] The seal 22 is integrally formed with the frame 21 and fixed to the frame 21. The seal 22 is baked onto the frame 21. The planar shape of the seal 22 is rectangular. The seal 22 is formed of, for example, rubber. As shown in FIGS. 5 and 6 , the seal 22 includes a first seal portion 221 located in the Z1 direction of the frame 21 and a second seal portion 222 located in the Z2 direction. The first seal portion 221 abuts against the cover 3 to seal between the frame 21 and the cover 3. The first seal portion 221 has two lip portions abutting against the cover 3. One of the two lip portions faces inward, and the other faces outward. The second seal portion 222 abuts against, for example, a side wall 921 of the housing 90 to seal between the side wall 921 and the frame 21. The second seal portion 222 has two lip portions that abut against, for example, the side wall 921 of the housing 90. One of the two lip portions faces inward, and the other faces outward. The second seal portion 222 and the first seal portion 221 overlap in a plan view. Therefore, the second seal portion 222 and the first seal portion 221 are provided at the same position in the XY plane.

[0024] In the illustrated example, the plurality of first protrusions 23 are two first protrusions 23. Each of the two first protrusions 23 is located in the X1 direction or the X2 direction of the frame 21 and is connected to the frame 21. Each first protrusion 23 protrudes from the frame 21 toward the outside of the housing, i.e., in the Z1 direction. Each first protrusion 23 is flat and extends along the Y-Z plane. Each first protrusion 23 is spaced apart from the cover 3.

[0025] 1A-2. Cover 3 The cover 3 is the part of the explosion-proof valve 100 that functions as a valve. The cover 3 is disposed on the opposite side of the mounting member 2 from the housing 90, i.e., in the Z1 direction relative to the mounting member 2. The cover 3 moves along the Z axis in response to the internal pressure of the housing 90 due to the spring portion 4. The planar shape of the cover 3 corresponds to the outer shape of the frame 21 of the mounting member 2. The cover 3 is a polygonal member that covers the through-hole 92H of the housing 90, specifically, a member that is rectangular in plan view. The planar area of ​​the cover 3 is set so that the outer edge of the cover 3 is located outside the seal 22. The cover 3 has a cover main body 31, a shaft portion 32, and multiple second protrusions 33.

[0026] The cover body 31 is a portion that covers the through-hole 92H when in contact with the mounting member 2. The seal 22 of the mounting member 2 comes into contact with the cover body 31, thereby sealing the through-hole 92H. The cover body 31 has a flat plate portion 311 and a bent portion 312. The flat plate portion 311 is a portion that extends in the XY plane and has a rectangular planar shape. The flat plate portion 311 abuts against the first seal portion 221 of the seal 22. The bent portion 312 is a portion that is bent from the outer edge of the flat plate portion 311 in the Z2 direction and extends along the Z axis. The bent portion 312 surrounds the seal 22 from the outside.

[0027] The shaft portion 32 is provided at the center of the cover main body 31. The shaft portion 32 protrudes from the Z2 direction surface of the cover main body 31 toward the through-hole 92H, i.e., in the Z2 direction. In the illustrated example, the planar shape of the shaft portion 32 is circular. The shaft portion 32 has a stepped surface 320. The stepped surface 320 is a surface along the XY plane. The stepped surface 320 has an annular shape. Furthermore, there is no noticeable step, and no notch or the like, in the portion of the shaft portion 32 further in the Z2 direction than the stepped surface 320.

[0028] In the illustrated example, the plurality of second protrusions 33 are two second protrusions 33. Each of the two second protrusions 33 is located in the X1 direction or the X2 direction of the cover main body 31 and is connected to the cover main body 31. The two second protrusions 33 are provided corresponding to the two first protrusions 23. Each second protrusion 33 protrudes from the cover main body 31 toward the corresponding first protrusion 23. Each second protrusion 33 is flat and parallel to the X-Y plane. The second protrusion 33, together with the first protrusion 23, functions as a rotation restricting portion that restricts rotation of the cover 3 relative to the mounting member 2.

[0029] 1A-3. Spring portion 4 The spring portion 4 has a biasing force that causes the cover 3 to abut against the seal 22 of the mounting member 2. The spring portion 4 is a collection of multiple leaf springs 41. The multiple leaf springs 41 are spaced apart at approximately equal intervals. Each leaf spring 41 is disposed between the cover 3 and the mounting member 2 and is fixed to the cover 3 and the mounting member 2.

[0030] The first ends 411 of each leaf spring 41 are fixed to the support portion 212 of the mounting member 2. The fixing method is not particularly limited and may be any method, such as adhesive bonding, welding, or press-fitting. The second ends 412 of each leaf spring 41 are connected to each other to form an annular ring portion 415. The second ends 412 of each leaf spring 41, i.e., the ring portion 415, abut against the stepped surface 320 of the shaft portion 32 of the cover 3.

[0031] Each of the leaf springs 41 is curved so that its center protrudes in the Z2 direction when the cover 3 is in contact with the mounting member 2. Each of the plurality of leaf springs 41 is displaced by the pressure inside the housing 90 to separate the cover 3 from the mounting member 2. The plurality of spring portions 4 are preferably made of metal from the viewpoint of heat resistance. As shown in FIG. 7 , each of the leaf springs 41 is located inside the support portion 212 in a plan view.

[0032] 1A-4. Fixing Member 5 The fixing member 5 shown in FIG. 3 is a member that fixes the spring portion 4, which includes a plurality of leaf springs 41, to the cover 3. The fixing member 5 has an insertion hole 5H through which the shaft portion 32 is inserted. The insertion hole 5H is much smaller than the outer diameter of the stepped surface 320, and is approximately the diameter of a portion of the shaft portion 32 that is located further in the Z2 direction than the stepped surface 320. The fixing member 5 is in the shape of a circular ring. From the viewpoint of heat resistance, the fixing member 5 is preferably made of metal. The fixing member 5 is, for example, a push nut.

[0033] FIG. 8 is a cross-sectional view of the fixing member 5, spring portion 4, and step surface 320 shown in FIG. 2 . As shown in FIG. 8 , the fixing member 5, the ring portion 415 of the spring portion 4, and the step surface 320 are aligned in this order in the Z1 direction. As described above, the step surface 320 is a surface along the X-Y plane. The step surface 320 is annular. The ring portion 415 is positioned in the Z2 direction of the step surface 320, and the fixing member 5 is positioned in the Z2 direction of the ring portion 415. With the shaft portion 32 inserted into the insertion hole 5H, the fixing member 5 clamps the ring portions 415, which are the second ends 412 of the multiple leaf springs 41, between the fixing member 5 and the step surface 320, thereby fixing the multiple leaf springs 41 to the cover 3. For example, with the spring portion 4 abutting against the step surface 320, the fixing member 5 is press-fitted onto the shaft portion 32.

[0034] Fig. 9 is a diagram showing a state in which the cover 3 shown in Fig. 5 is separated from the mounting member 2. Fig. 10 is a diagram showing a state in which the cover 3 shown in Fig. 6 is separated from the mounting member 2.

[0035] 5 and 6 is in contact with the seal 22 of the mounting member 2 by the biasing force of the plurality of leaf springs 41. The state of the cover 3 shown in Figures 5 and 6 is a state in which the difference between the internal pressure and the external pressure of the housing 90 is less than a predetermined pressure. In other words, the state of the cover 3 shown in Figures 5 and 6 is a state in which the internal pressure of the housing 90 has not risen significantly.

[0036] In contrast, the state of the cover 3 shown in Figures 9 and 10 is a state in which the difference between the internal pressure and the external pressure of the housing 90 is equal to or greater than a predetermined pressure. In other words, the state of the cover 3 shown in Figures 9 and 10 is a state in which the internal pressure of the housing 90 has risen significantly. When the difference between the internal pressure and the external pressure of the battery pack rises to or greater than a predetermined pressure, the cover 3 moves in the Z1 direction away from the mounting member 2 against the biasing force of the multiple leaf springs 41. As a result, the through-holes 92H that were blocked by the cover 3 are opened, and a large amount of gas inside the housing 90 is discharged to the outside through the through-holes 92H. This discharge releases the internal pressure of the housing 90. Once the internal pressure is released, the cover 3 moves in the Z2 direction so as to abut against the mounting member 2 as before. This opening of the cover 3 occurs in a very short time.

[0037] As described above, in this embodiment, the spring portion 4 is fixed to the cover 3 by the fixing member 5 and the stepped surface 320. Specifically, with the shaft portion 32 inserted into the insertion hole 5H, the fixing member 5 clamps the ring portion 415, which is the second end 412 of each of the plurality of leaf springs 41, between the fixing member 5 and the stepped surface 320, thereby fixing the plurality of leaf springs 41 to the cover 3. For this reason, the fixing member 5 is press-fitted onto the shaft portion 32, and the ring portion 415 of the spring portion 4 is pressed against the stepped surface 320.

[0038] The provision of such fixing members 5 can prevent movement of each leaf spring 41. Therefore, even if the cover 3 moves along the Z axis relative to the mounting member 2 due to the leaf springs 41, rotation of the cover 3 about the Z axis relative to the mounting member 2 can be suppressed. In other words, when the cover 3 moves in the Z1 direction to open the through-hole 92H and then returns in the Z2 direction, the cover 3 is prevented from rotating about the Z axis relative to the mounting member 2. This prevents the sealing performance of the cover 3 from changing before and after the cover 3 is opened. Therefore, even after the cover 3 is opened, the cover 3 can reliably block the inflow of oxygen, reducing the risk of the battery pack 900 catching fire.

[0039] Furthermore, the cover 3 is preferably made of metal, such as stainless steel. The metal cover 3 can have higher heat resistance than a resin cover 3. Therefore, the metal cover 3 can be used in a wider range of applications to various battery packs 900 than a resin cover 3.

[0040] As described above, the leaf spring 41 is fixed between the stepped surface 320 and the fixing member 5 by a simple structure in which the leaf spring 41 is sandwiched between them. Providing the stepped surface 320 on the shaft portion 32 is easy to process. Therefore, even when the cover 3 is made of metal, the cover 3 having the stepped surface 320 can be easily formed. For example, the cover 3 can be easily formed by press working. Note that the cover 3 may be formed by connecting the shaft portion 32 to the cover body 31 by welding. The cover 3 may also be made of resin.

[0041] Furthermore, the frame 21 of the mounting member 2 is rectangular, and the cover body 31 of the cover 3 is rectangular. If these are circular, even if the cover 3 rotates relative to the mounting member 2, the sealing performance is less likely to deteriorate due to misalignment of the cover 3 with respect to the mounting member 2. However, if the mounting member 2 and the cover 3 are polygonal, particularly rectangular, the sealing performance is more likely to deteriorate due to misalignment of the cover 3 in the rotational direction relative to the mounting member 2. For this reason, when the frame 21 of the mounting member 2 is rectangular, and the cover body 31 of the cover 3 is rectangular, fixing using the fixing member 5 described above is particularly effective in preventing such rotation. Furthermore, the first protrusion 23 and second protrusion 33 described below serve as rotation restrictors.

[0042] Fig. 11 is an enlarged view showing the first protrusion 23 and the second protrusion 33 shown in Fig. 4. Fig. 12 is an enlarged view showing the state in which the second protrusion 33 abuts against the first protrusion 23 shown in Fig. 4. As described above, the plurality of second protrusions 33 are provided corresponding to the plurality of first protrusions 23. Figs. 11 and 12 show one second protrusion 33 out of the plurality of second protrusions 33 and the first protrusion 23 corresponding thereto.

[0043] 11 , the second protrusion 33 protrudes from the cover main body 31 toward the first protrusion 23. When the cover 3 is not rotating at all around the Z axis relative to the mounting member 2, the second protrusion 33 is not in contact with the first protrusion 23, as shown in FIG. 11 . In this case, there is a slight gap between the second protrusion 33 and the first protrusion 23.

[0044] 12 , when the cover 3 rotates slightly relative to the mounting member 2, the second protrusion 33 abuts against the surface of the first protrusion 23 facing the cover 3. This restricts the rotation of the cover 3 relative to the mounting member 2. In other words, the abutment of the second protrusion 33 against the first protrusion 23 restricts the cover 3 from rotating further relative to the mounting member 2. This makes it possible to suppress the rotation of the cover 3 relative to the mounting member 2. This prevents the sealing performance of the cover 3 from changing before and after the cover 3 is opened.

[0045] 9 , the protrusion height T1 of each of the first protrusions 23 from the frame 21 is greater than the displacement of each of the leaf springs 41. Therefore, even when the cover 3 is separated from the frame 21, the tip 231 of the second protrusion 33 is positioned further in the Z1 direction than the first protrusion 23. Therefore, even while the cover 3 is separated from the frame 21, the first protrusion 23 and the second protrusion 33 can restrict rotation of the cover 3 relative to the mounting member 2.

[0046] 4 , in this embodiment, two of the multiple first protrusions 23 are provided on opposing sides of the frame 21. This makes it possible to more effectively restrict rotation of the cover 3 relative to the mounting member 2 compared to when the two first protrusions 23 are not provided on opposing sides. In particular, the two first protrusions 23 are provided on the two shorter sides of the four sides. This makes it possible to more effectively restrict rotation of the cover 3 relative to the mounting member 2 compared to when the two first protrusions 23 are provided on the longer sides.

[0047] The number of first protrusions 23 may be three or more. Similarly, the number of second protrusions 33 may be three or more. The first protrusions 23 may be provided on all four sides of the frame 21.

[0048] Although the explosion-proof valve of the present disclosure has been described above based on preferred embodiments, the present disclosure is not limited to the above-described embodiments. Furthermore, the configuration of each of the above-described parts can be replaced with any configuration that exhibits the same function as the above-described embodiments, and any configuration can be added.

[0049] 2. Supplementary Notes The following aspects, for example, can be understood from the above embodiment and modified examples.

[0050] A first aspect of the explosion-proof valve, which is a preferred example of the present disclosure, includes: a mounting member that is attached to a housing having a through hole in a side wall portion and that is arranged outside the through hole in a plan view of the through hole; a cover that is arranged on the opposite side of the mounting member from the housing and that covers the through hole; a plurality of leaf springs that are arranged between the cover and the mounting member and that are fixed to the mounting member and the cover, each of the plurality of leaf springs having a first end and a second end; and a fixing member that fixes the plurality of leaf springs to the cover, wherein each of the plurality of leaf springs is displaced by pressure inside the housing so as to separate the cover from the mounting member, and the mounting member The member comprises a polygonal metal frame and a frame-shaped seal fixed to the frame, the cover comprises a polygonal cover body that seals the through hole when the seal abuts against it, and an axle portion that protrudes from the center of the cover body toward the through hole, the frame of the mounting member comprises a support portion that supports each first end of the multiple leaf springs, the axle portion of the cover has a stepped surface, and the fixing member has an insertion hole through which the axle portion is inserted, and with the axle portion inserted into the insertion hole, the multiple leaf springs are fixed to the cover by clamping each second end of the multiple leaf springs between the fixing member and the stepped surface.

[0051] According to the first aspect, the fixing member restrains the rotation of the leaf spring, so that it is possible to restrain the rotation of the cover relative to the mounting member before and after the cover is opened.

[0052] In a second aspect which is a preferred example of the first aspect, the mounting member further comprises a plurality of plate-shaped first protrusions which protrude outward from the frame in a plan view of the housing, and the cover further comprises a plurality of plate-shaped second protrusions which are provided corresponding to the plurality of first protrusions and protrude from the cover body, and each of the plurality of second protrusions protrudes from the cover body toward a corresponding first protrusion among the plurality of first protrusions, and by abutting against the corresponding first protrusion, restricts rotational movement of the cover relative to the mounting member.

[0053] According to this explosion-proof valve, the first protrusion and the second protrusion function as rotation restricting portions, thereby further restricting rotation of the cover relative to the mounting member.

[0054] In a third aspect which is a preferred example of the second aspect, a protruding height of each of the first protrusions from the frame is greater than a displacement amount of each of the leaf springs.

[0055] According to this explosion-proof valve, even when the cover is spaced apart from the mounting member, i.e., when the cover is open, it is possible to prevent the cover from rotating relative to the mounting member.

[0056] In a fourth aspect which is a preferred example of the second aspect, the plurality of first protrusions include two first protrusions provided on opposing sides of the frame.

[0057] According to this explosion-proof valve, rotation of the cover relative to the mounting member can be suppressed more effectively than in a case where the two first protrusions are not provided on opposing sides.

[0058] In a fifth aspect which is a preferred example of the first aspect, the cover is made of metal.

[0059] Such an explosion-proof valve can improve heat resistance compared to a case where the cover is made of resin.

[0060] In a sixth aspect which is a preferred example of the first aspect, the frame has a rectangular frame shape, and the cover body has a rectangular shape.

[0061] With such an explosion-proof valve, when the frame is rectangular and the cover body is rectangular, the configuration of the present disclosure for preventing rotation of the cover relative to the mounting member is particularly useful compared to when the cover has other shapes.

[0062] 100... explosion-proof valve, 2... mounting member, 3... cover, 4... spring portion, 5... fixing member, 5H... insertion hole, 21... frame, 22... seal, 23... first protrusion, 31... cover body, 32... shaft portion, 33... second protrusion, 41... leaf spring, 211... frame body, 212... support portion, 213... mounting protrusion, 213H... hole, 221... first seal portion, 222... second seal portion, 231... tip, 311... flat plate portion, 312... bent portion, 320... step surface, 411... first end, 412... second end, 415... ring portion, 900... battery pack, 90... housing, 92... side wall portion, 92H... through hole, 921... side wall, 921H... screw hole, T1... protrusion height.

Claims

1. A mounting member attached to a housing having a through hole in a side wall portion and positioned outside the through hole in a plan view of the through hole; a cover positioned on the opposite side of the mounting member from the housing and covering the through hole; a plurality of leaf springs positioned between the cover and the mounting member and fixed to the mounting member and the cover, each leaf spring having a first end and a second end; and a fixing member fixing the plurality of leaf springs to the cover, wherein each of the plurality of leaf springs is displaced by pressure inside the housing to separate the cover from the mounting member, the mounting member comprising a polygonal metal frame and a frame-shaped seal fixed to the frame, the cover comprising a polygonal cover body against which the seal abuts to seal the through hole, and a shaft protruding from the center of the cover body towards the through hole, the frame of the mounting member comprising support portions supporting the first ends of the plurality of leaf springs, the shaft portion of the cover having a stepped surface, the fixing member has an insertion hole through which the shaft portion is inserted, and with the shaft portion inserted into the insertion hole, the second ends of the plurality of leaf springs are clamped between the fixing member and the stepped surface, thereby fixing the plurality of leaf springs to the cover.

2. An explosion-proof valve as described in claim 1, wherein the mounting member further comprises a plurality of plate-shaped first protrusions that protrude outward from the frame in a plan view of the housing, and the cover further comprises a plurality of plate-shaped second protrusions that are provided corresponding to the plurality of first protrusions and protrude from the cover body, and each of the plurality of second protrusions protrudes from the cover body toward a corresponding first protrusion among the plurality of first protrusions, and restricts rotational movement of the cover relative to the mounting member by abutting against the corresponding first protrusion.

3. The explosion-proof valve according to claim 2, wherein the protruding height of each of the plurality of first protruding portions from the frame is greater than the displacement of each of the plurality of leaf springs.

4. The explosion-proof valve according to claim 2, wherein the plurality of first protrusions include two first protrusions provided on opposing sides of the frame.

5. The explosion-proof valve according to claim 1, wherein the cover is made of metal.

6. The explosion-proof valve according to claim 1, wherein the frame is rectangular, and the cover body is rectangular.

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