JP2019053934A - Explosion-proof valve body for sealed electrochemical device - Google Patents

Abstract

To provide an explosion-proof valve body for sealed electrochemical device in which variation of fracture strength of the valve body is suppressed, and dimensional accuracy of the attachment part is high.SOLUTION: Gas outlet in the sealing board of a sealed electrochemical device is blocked by an explosion-proof valve body 1, and when the internal pressure of the device increases, the explosion-proof valve body fractures to exhaust the gas. The explosion-proof valve body 1 is formed in such a shape that a cylindrical part 14 projects from a flat tabular part 11, by injection moulding of thermoplastic resin. The portion of the tabular part 11 located farther outside than the cylindrical part 14 is a collar part 12, and the explosion-proof valve body 1 is integrated with the sealing board of the device by the collar part 12. Multiple gate marks GR, GR are placed in the collar part 12 while spaced apart in the hoop direction, and a weld W is formed to substantially pass the center of a destruction part 13 of the tabular part 11, located farther inside than the cylindrical part 14.SELECTED DRAWING: Figure 2

Description

The present invention relates to an explosion-proof valve body in a sealed electrochemical device such as a capacitor or a battery, in which when the pressure inside the device increases, the valve body is opened to release the pressure.

Sealed electrochemical devices such as capacitors and batteries having an electrolytic solution in a sealed case are used in various applications. In particular, in recent years, such a sealed electrochemical device has been widely used as a secondary battery for charging and discharging.
These devices are hermetically sealed so that the electrolyte does not leak out of the case, but if the electrolyte is decomposed by leaving it under high temperature, short-circuiting, overcharging, reverse charging, etc. May occur. When the internal pressure of the device increases due to the generated gas, the device may burst. Therefore, an explosion-proof valve body is provided in the gas discharge hole of the sealing plate of the device, and the valve body is opened by increasing the internal pressure of the device to prevent the device from bursting.

For example, Patent Document 1 discloses an explosion-proof valve body having a shaft portion, a groove portion, and a flange portion, and is broken at a thin portion of the groove portion so that gas can be discharged at once. This explosion-proof valve body is injection-molded with a synthetic resin.

JP 2015-29029 A

Such an explosion-proof valve body is integrated in a sealed state with respect to a case of a sealed electrochemical device, particularly a sealing plate. For this reason, in the explosion-proof valve body, the mounting portion (the flange portion in the explosion-proof valve body of Patent Document 1) needs to be formed in an accurate shape.

However, in the explosion-proof valve body of Patent Document 1, while the concave groove portion to be broken is formed thin, it is necessary to form a thick shaft portion or the like, and the dimensional accuracy of the explosion-proof valve body tends to be low. there were. This is because, in the injection molding process of the explosion-proof valve body, when forming a thin groove portion to be broken, it becomes difficult for the resin to flow in the thin portion, or cooling proceeds easily in the thin groove portion, and other parts This is because a temperature difference and a pressure difference are likely to occur between and the explosion-proof valve body as a molded body, which tends to be warped and distorted.

In addition, the explosion-proof valve body is designed so that when the internal pressure of the device reaches a predetermined pressure, the valve body is destroyed so that the valve body can be quickly broken and the internal gas can be quickly discharged to reduce the pressure. There is a demand for the strength to fall within a predetermined range.

An object of the present invention is to provide an explosion-proof valve body for a sealed electrochemical device that can suppress variation in the breaking strength of the valve body and has a high dimensional accuracy of the mounting portion.

As a result of intensive studies, the inventor has made the shape of the explosion-proof valve body a combination of a plate-like portion and a cylindrical portion, and in the injection molding of the explosion-proof valve body, the gate is arranged at a plurality of locations, It has been found that the above-mentioned problems can be solved by passing through a predetermined position, and the present invention has been completed.

The present invention is an explosion-proof valve body for a sealed electrochemical device that closes a gas discharge hole of a sealing plate of a sealed electrochemical device and breaks and discharges gas when the internal pressure of the device increases. The valve body is formed by injection molding of a thermoplastic resin into a shape in which the tubular portion protrudes from the flat plate-like portion, and a portion of the plate-like portion that is located outside the tubular portion is a flange. As the part, the explosion-proof valve body is integrated with the sealing plate at the collar part, and a plurality of gate marks are arranged in the collar part so as to be separated from each other in the circumferential direction. This is an explosion-proof valve body for a sealed electrochemical device in which a weld is formed so that a portion located inside the portion is a destruction portion and the destruction portion passes through substantially the center of the destruction portion (first invention) ).
In addition, a gate trace is a trace of the gate part at the time of injection-molding an explosion-proof valve body.

In the first invention, preferably, the fracture portion and the collar portion have substantially the same thickness (second invention). In the first invention or the second invention, the number of gate marks is preferably either 3 or 4 (third invention). In any one of the first to third inventions, the plurality of gate marks are preferably arranged at positions symmetrical with respect to a line passing through the approximate center of the destruction portion (fourth invention). In any one of the first to third inventions, preferably, the plurality of gate traces are arranged at an equiangular arrangement with respect to the approximate center of the destruction portion (fifth invention).

According to the explosion-proof valve body (first invention) of the present invention, the position of the weld is accurately adjusted, and variation in the breaking strength of the valve body can be suppressed. Moreover, the dimensional accuracy of the attachment part of an explosion-proof valve body can also be improved.

In particular, in the case of the second invention, the dimensional accuracy of the mounting portion of the explosion-proof valve body is particularly improved. In addition, in the case of the third invention, the fourth invention, and the fifth invention, it is possible to more effectively suppress the variation in the breaking strength of the valve body by making it easier to adjust the position of the weld. it can.

It is a cross-sectional schematic diagram which shows the state by which the explosion-proof valve body was attached to the sealed electrochemical device. It is the front view and sectional drawing of the explosion-proof valve body of 1st Embodiment. It is a cross-sectional schematic diagram which shows the process in which the explosion-proof valve body of 1st Embodiment is attached to a sealing board. It is the front view and sectional drawing of the explosion-proof valve body of 2nd Embodiment. It is the front view and sectional drawing of the explosion-proof valve body of 3rd Embodiment. It is the front view and sectional drawing of the explosion-proof valve body of 4th Embodiment.

Hereinafter, embodiments of the invention will be described with reference to the drawings, taking as an example the case where the sealed electrochemical device is a battery. The invention is not limited to the individual embodiments shown below, and can be carried out by changing the form.

FIG. 1 shows a sealed electrochemical device 9 having an explosion-proof valve body 1 according to the first embodiment. The sealed electrochemical device 9 is a battery. A positive and negative electrode element portion 8 is arranged inside the box-shaped case 4 and filled with the electrolyte solution 7 to constitute a battery. The opening of the case 4 is sealed with a sealing plate 3. The case 4 and the sealing plate 3 are made of metal, synthetic resin, or the like, and are joined together in a form that can be sealed by means such as welding or adhesion.

The sealing plate 3 is provided with a hole for an electrode, and the positive electrode terminal 5 and the negative electrode terminal 6 are provided in the hole so as to penetrate the sealing plate 3. The space between the sealing plate 3 and the positive electrode terminal 5 or the negative electrode terminal 6 is appropriately sealed with gaskets 5G and 6G. The positive electrode terminal 5 is electrically connected to the positive electrode of the positive and negative electrode element portion 8 by a lead wire 51, and the negative electrode terminal 6 is electrically connected to the negative electrode of the positive and negative electrode element portion 8 by a lead wire 61.

The sealing plate 3 is provided with a gas discharge hole 31, and the explosion-proof valve body 1 is integrated with the sealing plate 3 so as to cover and close the gas discharge hole 31. As will be described later, when gas is generated inside the sealed electrochemical device 1 and the internal pressure of the device rises, the destruction portion 13 of the explosion-proof valve body 1 is broken and released, and the internal gas is discharged. Is done.

The explosion-proof valve body 1 will be described. As shown in FIG. 2, the explosion-proof valve body 1 is formed by injection molding of a thermoplastic resin into a shape in which a cylindrical portion 14 protrudes from a flat plate-like plate-like portion 11.

Examples of the thermoplastic resin forming the explosion-proof valve body 1 include polyethylene (PE) resin, polypropylene (PP) resin, polystyrene (PS) resin, polyamide (PA) resin, polycarbonate (PC) resin, and polyvinyl chloride (PVC) resin. And thermoplastic resins such as polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, fluorine (F) resin, and polyether ether ketone (PEEK) resin. These thermoplastic resins can be used alone or blended, and may contain a filler and various compounding agents as appropriate.

In the explosion-proof valve body 1 according to the first embodiment shown in FIG. 2, the plate-like portion 11 has a disk shape. The plate-like portion may be rectangular as in other embodiments described later. Moreover, in this embodiment, the cylindrical part 14 is cylindrical. As in other embodiments to be described later, the cylindrical portion may be a rectangular tube.
In the present embodiment, the cylindrical portion 14 is provided so as to protrude on one surface of the plate-like portion 11, but the cylindrical portion may be provided so as to protrude on both surfaces of the plate-like portion 11.

Of the plate-like part 11, a part positioned radially outward from the cylindrical part 14 is referred to as a collar part 12, and a part of the plate-like part 11 positioned radially inside of the cylindrical part 14 is a destruction part 13. And Although the cylindrical part 14, the collar part 12, and the destruction part 13 are preferably arranged and formed concentrically as in the present embodiment, this is not essential.

The explosion-proof valve body 1 is arranged so that the cylindrical portion 14 enters the gas discharge hole 31 of the sealing plate 3, and is integrated with the sealing plate 3 by the collar portion 12. The integration of both is performed over the entire circumference of the collar portion 12 so that the airtightness and liquid tightness between the sealing plate 3 and the explosion-proof valve body 1 are maintained. The means for integrating the explosion-proof valve body 1 with the sealing plate 3 is not particularly limited, but is preferably integrated by adhesion or welding. A mounting member may be provided separately, and the collar portion 12 may be fixed so as to be pressed against the sealing plate 3. Further, a sealing member may be appropriately sandwiched between the explosion-proof valve body 1 and the sealing plate 3 to improve the sealing performance of both.

Since the explosion-proof valve body 1 is a member formed by injection molding of a thermoplastic resin, the explosion-proof valve body 1 has gate marks GR and GR. A plurality of gate marks GR and GR are arranged in the collar portion 12 of the explosion-proof valve body 1 so as to be separated from each other in the circumferential direction. The gate trace is a trace in the molded body of the mold when the explosion-proof valve body is injection-molded, where the gate serving as the resin injection path into the cavity is provided.

In the present embodiment, two gate marks GR and GR are provided on the outermost peripheral portion of the collar portion 12, and the gate marks GR and GR are lines (for example, upper and lower in the figure) that pass through the approximate center of the destruction portion 13. It is arranged at a position symmetrical to the line extending in the direction, the weld line W). Further, in the present embodiment, at the same time, the two gate marks GR and GR are arranged at an equal angle with respect to the approximate center of the destruction part 13, that is, the gate traces with the approximate center of the destruction part 13 as the center of the circle. It arrange | positions so that the center angle of the position where GR and GR are arrange | positioned may mutually become 180 degree | times.

A weld W is formed in the destruction portion 13 so as to pass through the approximate center of the destruction portion 13. That is, the explosion-proof valve body 1 is molded so that the weld W formed at the position where the resin flowing into the cavity from the plurality of gates GR and GR merges at the time of injection molding passes through the approximate center of the breaking portion 13. Yes. Note that the weld W does not have to pass through the exact center of the destruction portion 13, and the distance between the center of the destruction portion 13 and the weld W is plus or minus 15% of the diameter (major axis) of the destruction portion 13. If it is within the range, it can be considered that the weld W passes through the substantial center of the destruction portion 13.

Although it is not essential, it is preferable that the dimensions of the plate-like portion 11 (the collar portion 12 and the breaking portion 13) and the cylindrical portion 14 are as follows. It is preferable that the thickness t1 of the collar portion 12 and the thickness t2 of the destruction portion 13 are substantially the same thickness. In this way, the dimensional accuracy of the explosion-proof valve body is further improved. Further, the thickness t1 of the collar portion 12 may be made thicker than the thickness t2 of the destruction portion 13.

It is preferable that the thickness t3 of the cylindrical portion 14 be smaller than the thickness t1 of the collar portion 12. Moreover, it is preferable that the wall thickness t3 of the cylindrical portion 14 be smaller than the height H of the cylindrical portion 14. This also contributes to further improving the dimensional accuracy of the explosion-proof valve body.

Moreover, although not essential, it is also preferable to provide the annular concave groove 15 in the plate-like part 11 on the side opposite to the side on which the cylindrical part 14 protrudes like the explosion-proof valve body 1 of the present embodiment. . The concave groove 15 is provided so as to overlap with a position where the cylindrical portion 14 is provided. Providing such a concave groove 15 also makes it possible to make the substantial thickness of the molded explosion-proof valve body uniform, so that the cooling of the resin proceeds uniformly, and the dimensions of the explosion-proof valve body. The accuracy is further increased.

The explosion-proof valve body 1 and the sealed electrochemical device 9 of the above embodiment are formed by a known method. The explosion-proof valve body 1 is molded by a thermoplastic resin injection molding method. A mold capable of forming a cavity having a shape corresponding to the outer surface shape of the explosion-proof valve body 1 is prepared. The mold is provided with a route for injecting resin, and a plurality of gates are provided at positions corresponding to the plurality of gate marks GR and GR of the explosion-proof valve body 1.

When high-temperature molten resin is injected into the mold in the injection molding process, the resin is supplied to the mold cavity through a plurality of gates. The molten resin fills the cavity while expanding in the cavity starting from each gate. At this time, in this embodiment, since the gates are arranged symmetrically or arranged at an equal angle, the resin injected from the respective gates merges at a substantially central portion of the cavity, and this portion A weld is formed. In this manner, the explosion-proof valve body 1 having a plurality of gate marks and having the weld W passing through the approximate center of the destruction portion 13 as in the above embodiment is formed.

The arrangement of the plurality of gates is not limited to the arrangement of the above embodiment, and may be a gate arrangement as in other embodiments described later, for example. Further, as long as the weld W can pass through substantially the center of the destruction portion 13, the arrangement of the plurality of gates does not need to be symmetrical or equiangular. Even if the gates are arranged asymmetrically or at an unequal angle, the position where the weld W is formed may be adjusted by adjusting the thickness and length of the gate, the resin pool in the supply path, and the like.

The molded explosion-proof valve body 1 is attached to the sealing plate 3 of the sealed electrochemical device 9 by a known method. The explosion-proof valve body 1 is attached so as to cover the gas discharge hole 31 provided in the sealing plate 3 and close the gas discharge hole 31. For example, as shown in FIG. 3, both are arranged so that the cylindrical portion 14 of the explosion-proof valve body 1 enters the gas discharge hole 31 of the sealing plate 3 (FIG. 3A), and the collar portion 12 is placed in the gas discharge hole. What is necessary is just to adhere to the peripheral part of 31 with an adhesive agent, and to integrate both in a sealing form (FIG.3 (b)).

The operation and effect of the explosion-proof valve body 1 of the first embodiment will be described.
In the explosion-proof valve body 1 of the above-described embodiment, a plurality of gate marks GR and GR are arranged in the collar portion 12 so as to be spaced apart from each other in the circumferential direction, and a weld W is formed so as to pass through the approximate center of the destruction portion 13. Therefore, variation in the breaking strength of the valve body can be suppressed.

In the explosion-proof valve body 1, when the internal pressure increases, the destruction portion 13 is destroyed and the internal gas is released. At this time, if there is a weld W in the destruction portion, the strength of the weld portion is higher than that of a normal portion. Is low (typically, the strength is reduced by about 40 to 60%), so that breakage tends to occur starting from the weld W. On the other hand, the stress generated in the fracture portion 13 exposed to the internal pressure generally becomes maximum at the central portion of the fracture portion, and shows a tendency for the stress to decrease toward the periphery.

For this reason, if the distance between the center of the weld W and the destruction portion 13 becomes large, the destruction strength of the valve body varies, which is not preferable. In the explosion-proof valve body 1 of the above-described embodiment, since there are a plurality of gates (scratches), it becomes easy to accurately adjust the weld W so that it passes through the approximate center of the destruction portion 13, and therefore, variation in the destruction strength of the valve body Can be suppressed.

Moreover, in the explosion-proof valve body 1 of the said embodiment, since the destruction part 13 is destroyed starting from the weld W and it is not necessary to make an extremely thin place in a part of the valve body, The dimensional accuracy can also be increased. In the conventional explosion-proof valve body as described in Patent Document 1, it is necessary to form a thin portion where the valve body should be destroyed. When such a thin portion is provided, the thin portion is cooled quickly. In the thick-walled part, the cooling is slow, so in the injection molding process of the explosion-proof valve body, the cooling and holding pressure of the molded body become uneven, and the molded body warps, distorts, and sinks. The dimensional accuracy of the body mounting part tended to deteriorate.

In the explosion-proof valve body 1 of the above-described embodiment, since the destruction part is destroyed starting from the weld W passing through the approximate center of the destruction part 13, it is not necessary to make an extremely thin place in the valve body. As a result, it is possible to improve the dimensional accuracy of the explosion-proof valve body 1, particularly the flatness of the collar portion 12 serving as the attachment portion. When the flatness of the collar portion 12 is improved, there is an advantage that the degree of sealing of the portion where the collar portion and the sealing plate 3 are integrated is improved.

In addition, the improvement of the dimensional accuracy in the explosion-proof valve body 1 of the above embodiment also contributes to the fact that the explosion-proof valve body 1 is formed in a shape in which the cylindrical portion 14 projects from the flat plate-like plate-like portion 11. . When attempting to lower the internal pressure at which the destruction portion 13 breaks, the thickness of the destruction portion 13 and the thickness of the collar portion 12 are reduced, but the cylindrical portion 14 is formed so as to protrude from the plate-like portion. This is because even if the plate-like portion is thin, the collar portion is less likely to warp or deform during molding. From this viewpoint, it is preferable that the shape of the cylindrical portion is such that the height H is greater than the thickness t3.

In addition, from the viewpoint of more effectively increasing the dimensional accuracy of the mounting portion of the explosion-proof valve body 1, the fracture portion 13 and the collar portion 12 have substantially the same thickness (t1≈t2) as in the first embodiment. Is preferred. If both have substantially the same thickness, the degree of cooling of the injected resin is prevented from greatly differing between the two, and warping and distortion may occur when the molded explosion-proof valve body is cooled. It is because it is suppressed.

Further, from the viewpoint of more effectively suppressing the variation in the breaking strength of the valve body, as in the first embodiment, the plurality of gate marks GR and GR provided on the collar portion 12 are substantially at the center of the breaking portion 13. It is preferable to be arranged at a position that is symmetric with respect to a line passing through (for example, a line extending in the vertical direction in FIG. 2). This makes it easy to accurately adjust the weld W so that it passes through the approximate center of the destruction portion 13, and the weld W that passes through the approximate center of the destruction portion 13 is generated in a straight line. It is because it becomes easy to crack by the stress by the internal pressure.

For the same reason, as in the first embodiment, it is preferable that the plurality of gate marks GR, GR provided on the collar portion 12 are arranged so as to be equiangular with respect to the approximate center of the destruction portion. . This makes it easy to accurately adjust the weld W so that it passes through the approximate center of the destruction portion 13, and the weld W that passes through the approximate center of the destruction portion 13 is generated in a straight line. It is because it becomes easy to crack by the stress by the internal pressure.

The invention is not limited to the embodiment described above, and can be implemented with various modifications. Although other embodiments of the invention will be described below, in the following description, portions different from the above-described embodiment will be mainly described, and detailed descriptions of the same portions will be omitted. Moreover, these embodiments can be implemented by combining some of them or replacing some of them.

In FIG. 4, the explosion-proof valve body 21 of 2nd Embodiment is shown. In the explosion-proof valve body 21 of the second embodiment, a cylindrical tubular portion 214 is formed to protrude from a disk-shaped plate-shaped portion, and a plurality of gate marks GR and GR are spaced apart from each other in the collar portion 212 in the circumferential direction. This is the same as the explosion-proof valve body 1 of the first embodiment in that the weld W passes through the approximate center of the destruction part 213.

In the explosion-proof valve body 21 of the second embodiment, the thickness of the destruction part 213 is made thinner than the collar part 212. The thickness of the destruction part 213 may be made thinner than the collar part as long as the dimensional accuracy of the collar part 212 is not adversely affected.

Moreover, in the explosion-proof valve body 21 of the second embodiment, the arrangement of the plurality of gate marks GR and GR is symmetrical with respect to a line (vertical line in FIG. 4) passing through the approximate center of the destruction part 213. However, they are not arranged so as to be equiangular with respect to the approximate center of the destruction portion. Even in such an arrangement, the linear gate marks W can be accurately arranged as long as they are arranged symmetrically.
That is, even in the explosion-proof valve body 21 of the second embodiment, variation in the breaking strength of the valve body can be suppressed, and the dimensional accuracy of the mounting portion of the explosion-proof valve body can be improved.

In FIG. 5, the explosion-proof valve body 22 of 3rd Embodiment is shown. In the explosion-proof valve body 22 of the third embodiment, the cylindrical portion 224 protrudes from the plate-like portion, and a plurality of gate marks GR and GR are provided in the collar portion 222 apart from each other in the circumferential direction. The point that the weld W passes through the approximate center of the destruction part 223 is the same as that of the explosion-proof valve body 1 of the first embodiment.

In the explosion-proof valve body 22 of the third embodiment, the plate-like portion is formed in a rectangular shape, particularly a rectangular shape, and the cylindrical portion is formed in a rectangular tube shape. Thus, the shape of the plate-like part, the cylindrical part, and the collar part may not be circular or cylindrical. In the explosion-proof valve body 22 of the third embodiment, a total of four gate marks GR and GR are provided in each of the corner portions on the outer peripheral side of the collar portion 222. By arranging the gate marks GR and GR in this way, the weld W is formed in a cross shape passing through the approximate center of the destruction portion 223.

Even in the explosion-proof valve body 22 of the third embodiment, variation in the breaking strength of the valve body can be suppressed, and the dimensional accuracy of the mounting portion of the explosion-proof valve body can be increased.
In particular, since the four gate marks are provided apart in the circumferential direction, the weld W is formed in a cross shape passing through the approximate center of the fracture portion 223, so that it is easy to adjust the fracture strength starting from the weld portion. The variation in the breaking strength of the valve body can be suppressed more effectively.

Further, in the explosion-proof valve body 22 of the third embodiment, the thickness of the tubular portion 224 is made smaller than the thickness of the collar portion 222 and the thickness of the destruction portion 223. This is also preferable because it is effective in improving the cooling uniformity of the plate-like portion and improving the dimensional accuracy of the attachment portion of the explosion-proof valve body 22.

In FIG. 6, the explosion-proof valve body 23 of 4th Embodiment is shown. In the explosion-proof valve body 23 of the fourth embodiment, a plurality of gate marks GR, GR are provided in the circumferential direction away from the point where the cylindrical part 234 is formed to protrude from the plate-like part, The point that the weld W passes through the approximate center of the destruction part 233 is the same as that of the explosion-proof valve body of the other embodiments. Even in the explosion-proof valve body 23 of the fourth embodiment, variation in the breaking strength of the valve body can be suppressed, and the dimensional accuracy of the mounting portion of the explosion-proof valve body can be improved.

In the explosion-proof valve body 23 of the fourth embodiment, the cylindrical portion 234 is provided so as to protrude from both surfaces of the plate-like portion. If the cylindrical portions are protruded on both sides, the dimensional accuracy of the mounting portion of the explosion-proof valve body can be more effectively increased while suppressing the protruding amounts of the respective cylindrical portions 234 and 234.

Further, in the explosion-proof valve body 23 of the fourth embodiment, the three gate marks GR and GR are arranged so as to be equiangularly arranged at intervals of 120 degrees with respect to the approximate center of the destruction part. With such an arrangement, since the weld W is formed in a trifurcated shape passing through the approximate center of the destruction portion 233, the fracture strength starting from the weld portion is adjusted in the same manner as the explosion-proof valve body 22 of the third embodiment. It becomes easy and can suppress the dispersion | variation in the fracture strength of a valve body more effectively. From this viewpoint, the number of gate marks is particularly preferably three or four.

In the explosion-proof valve body 23 of the fourth embodiment, the gate marks GR and GR are provided in the center portion in the radial direction of the collar portion 232. The position of the gate mark is preferably the outermost peripheral portion of the collar portion as in the first to third embodiments in order to increase the dimensional accuracy, but as in the fourth embodiment, the position of the collar portion is preferred. The central portion in the radial direction may be used, or the inner peripheral side of the collar portion may be used.

In the description of the above embodiment, the case where the sealed electrochemical device to which the explosion-proof valve body is applied is a battery has been described. The battery may be a primary battery such as an alkaline battery, a secondary battery such as a lithium ion battery, or other battery, and is not particularly limited. The sealed electrochemical device to which the explosion-proof valve body is applied may be an electrolytic capacitor.

The explosion-proof valve body can be used for a sealed electrochemical device, and can discharge gas generated inside the sealed electrochemical device, so that it has high industrial utility value.

DESCRIPTION OF SYMBOLS 1 Explosion-proof valve body 11 Plate part 12 Collar part 13 Destruction part 14 Cylindrical part GR Gate mark W Weld 3 Sealing plate 4 Case 5 Positive electrode terminal 6 Negative electrode terminal 7 Electrolyte 8 Positive / negative electrode element part 9 Sealed electrochemical device (battery )

Claims (5)

It is an explosion-proof valve body for a sealed electrochemical device that closes the gas discharge hole of the sealing plate of the sealed electrochemical device and breaks and discharges gas when the internal pressure of the device rises.
The explosion-proof valve body is formed by injection molding of a thermoplastic resin into a shape in which the cylindrical portion protrudes from the flat plate-like portion,
Of the plate-like part, the part located outside the cylindrical part as a collar part,
The explosion-proof valve body is integrated with the sealing plate at the collar,
In the collar portion, a plurality of gate marks are arranged spaced apart in the circumferential direction,
Of the plate-like part, the part located inside the cylindrical part as the destruction part,
An explosion-proof valve body for a sealed electrochemical device in which a weld is formed in the destruction portion so as to pass through the approximate center of the destruction portion. The explosion-proof valve body for a sealed electrochemical device according to claim 1, wherein the destruction part and the collar part have substantially the same thickness. The explosion-proof valve body for a sealed electrochemical device according to claim 1 or 2, wherein the number of gate marks is 3 or 4. The explosion-proof valve body for a sealed electrochemical device according to any one of claims 1 to 3, wherein the plurality of gate marks are arranged at positions symmetrical with respect to a line passing through the approximate center of the destruction portion. The explosion-proof valve body for a sealed electrochemical device according to any one of claims 1 to 3, wherein the plurality of gate traces are arranged so as to be equiangularly arranged with respect to a substantially center of the destruction portion.

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