Explosion-proof valve for sealed power storage device
The groove pattern in the explosion-proof valve for sealed energy storage devices ensures reliable opening at desired pressures with a stable shape by concentrating stress at a central point, addressing the complexity issues of previous designs.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- AISAN IND CO LTD
- Filing Date
- 2025-12-12
- Publication Date
- 2026-06-25
Smart Images
Figure JP2025043431_25062026_PF_FP_ABST
Abstract
Description
Explosion-proof valve of a sealed energy storage device
[0001] The present disclosure relates to an explosion-proof valve of a sealed energy storage device.
[0002] In a part of the sealed container of a sealed battery or capacitor (sealed energy storage device), an explosion-proof valve composed of a thin film portion with grooves formed therein is provided. When the pressure inside the sealed container rises abnormally, the thin film portion of the explosion-proof valve cracks at the groove location and discharges the internal gas, thereby preventing the explosion of the battery or capacitor. Various groove patterns (groove patterns) have been disclosed regarding what kind of grooves to form in the thin film portion, which is the explosion-proof valve.
[0003] For example, Japanese Unexamined Patent Application Publication No. 2009-099301 discloses a battery pack having a thin film portion with a groove pattern of two intersecting straight lines.
[0004] Japanese Unexamined Patent Application Publication No. 2021-136194 also discloses an explosion-proof valve of a sealed energy storage device having a groove pattern shown in FIG. 10 as one of the groove patterns.
[0005] Analysis by the inventors has revealed that in the groove pattern of the battery pack described in Japanese Unexamined Patent Application Publication No. 2009-099301, the residual stress generated at the intersection of the two straight lines is higher than the residual stress generated in the groove portions other than the intersection. Therefore, if the magnitude of the residual stress generated at the intersection is not considered, there is a possibility that the pressure at the start of fracture will be lower than the assumed range. For this reason, a groove pattern having two intersecting straight lines requires consideration of the magnitude of the residual pressure generated at the intersection, which may lead to complication of design and manufacturing, so it is not preferable.
[0006] Furthermore, various groove patterns are disclosed for explosion-proof valves of sealed energy storage devices described in Japanese Patent Application Publication No. 2021-136194. An example of the groove pattern shape in Figure 13 will be explained as prior art, shown in Figure 10 of this application. In the groove pattern 120 shown in Figure 10, in each second groove 132 extending from the end of the linear first groove 131, the radius RY of the arc of the second arc portion 143 is greater than or equal to the radius RX of the arc of the first arc portion 141. As a result, the area of the region enclosed by the first groove 131, the first arc portion 141, the first linear portion 142, the second arc portion 143, and the second linear portion 144 (the area that receives internal pressure) is slightly smaller, and it cannot rupture at lower pressures. In recent years, it has been desirable for the valve to rupture at lower pressures.
[0007] The objective of this disclosure to solve the above problems is to provide an explosion-proof valve for a sealed energy storage device that can be opened at lower pressure without complicating the design or manufacturing process.
[0008] To solve the above problems, the explosion-proof valve of the sealed energy storage device of this disclosure takes the following measures.
[0009] One embodiment of the present disclosure is an explosion-proof valve for a sealed energy storage device, the explosion-proof valve comprising a thin-walled portion provided in a sealed container of the sealed energy storage device, the thin-walled portion which ruptures when the internal pressure of the sealed container increases, and the thin-walled portion having a groove pattern which breaks when it ruptures. The groove pattern comprises a first groove, a second groove, and a third groove. The first groove is a straight line passing through approximately the center of the thin-walled portion, with both its one end and the other end extending to just before the edge of the thin-walled portion, dividing the thin-walled portion into a first region and a second region. The second groove is a groove extending from one end of the first groove to the second region of the thin-walled portion, and a groove extending from the other end of the first groove to the first region of the thin-walled portion. The third groove is a groove extending from one end of the first groove to the first region of the thin-walled portion, and a groove extending from the other end of the first groove to the second region of the thin-walled portion. Each of the second grooves has a first arc portion, a first straight portion, a second arc portion, and a second straight portion. The first arc portion is an arc shape that is convex toward the edge of the thin film portion, with one end and the other end of the first groove as its starting points. The first straight portion extends linearly from the end of the first arc portion so as to be substantially parallel to the first groove. The second arc portion is an arc shape that extends toward the first groove from the end of the first straight portion. The second straight portion extends linearly from the end of the second arc portion to just before the first groove. The end of the second straight portion is the end of the second groove. Each of the third grooves has a third arc portion and a third straight portion. The third arc portion is an arc shape that is convex toward the edge of the thin film portion, with one end and the other end of the first groove as its starting points. The third straight section extends linearly from the end of the third arc section to just before the second arc section, substantially parallel to the first groove. The end of the third straight section is the end of the third groove. The end of the third groove extends in the direction along the first groove to the end of the first straight section of the second groove adjacent to the first groove, straddling the first groove. The radius of the second arc section is smaller than the radius of the first arc section.
[0010] This figure illustrates an example of the external appearance of a sealed energy storage device. This is a cross-sectional view taken along line II-II of the sealed energy storage device shown in the example in Figure 1. This is a perspective view of the sealing plate of a sealed container. This is an enlarged view of the thin film portion formed on the sealing plate shown in the example in Figure 3. This is a plan view of the sealing plate of a sealed container. This is a cross-sectional view taken along line VI-VI of Figure 5. This is an enlarged view of section VII shown in Figure 6. This is an enlarged view of section VIII shown in Figure 7. This is an enlarged view of the thin film portion in Figure 5, illustrating the shape of the groove pattern provided on the thin film portion. This figure illustrates an example of the shape of a conventional groove pattern. This figure illustrates an example of the valve opening shape when the explosion-proof valve is opened. This figure illustrates the relationship between the length of distance D4, the valve opening shape (pattern A, pattern B, pattern C), and the evaluation results. This is the simulation result of the distance D4 and the central displacement of the explosion-proof valve when the internal pressure of the container is 0.4 [MPa] (and the explosion-proof valve does not open).
[0011] <Appearance (Figure 1) and Structure (Figure 2) of Sealed Energy Storage Device 1> The embodiments will be described below based on the drawings. Figure 1 shows a schematic overview of the appearance of a sealed energy storage device 1 as one embodiment. The sealed energy storage device 1 is a battery or capacitor, and its components 6, such as electrodes, active material, electrolyte, and dielectric, are housed inside a sealed container 4.
[0012] The sealed container 4 is made of, for example, an aluminum alloy and is shaped like a rectangular parallelepiped. However, the material and shape of the sealed container 4 are not limited to these. The sealed container 4 has a roughly cylindrical container body 8 with one end closed at the bottom and the other end open, and a sealing plate 10 that closes the opening of the container body 8. The sealing plate 10 is joined to the opening of the container body 8 around its entire circumference by, for example, laser welding, so as to create an airtight seal.
[0013] The sealing plate 10 is made of a metal such as an aluminum alloy. The container body 8 and the sealing plate 10 may be made of the same metal material or different metal materials. The sealing plate 10 is shaped to correspond to the opening of the container body 8, and is, for example, rectangular. The sealing plate 10 may also be provided with necessary holes, such as holes 14 for inserting terminals 12 that are electrically connected to the electrodes of the components 6 housed in the sealed container 4, and holes (not shown) for injecting electrolyte. However, these holes are sealed by appropriate means during manufacturing.
[0014] The thin film portion 16 is formed at a predetermined position on the sealing plate 10 and functions as an explosion-proof valve 15. The thin film portion 16 is an explosion-proof valve 15. As shown in Figures 1 and 2, when there are terminals 12 near both ends of the sealing plate 10, the thin film portion 16 is positioned, for example, between the two terminals 12. When one of the terminals 12 is near the center of the sealing plate 10, the thin film portion 16 is positioned, for example, near one of the terminals 12.
[0015] <Sealing plate 10 and thin film portion 16 (Figures 3 to 7)> The shape of the thin film portion 16 is as shown in Figures 3 to 5, with the ends of two parallel straight lines connected by an arc, which is the shape of a running track (also called an oval shape, rounded rectangle, or ellipse). However, it is not limited to this shape, and may be circular or elliptical. As shown in Figures 3 and 4, the thin film portion 16 is formed integrally with the other parts of the sealing plate 10, with a recess 18 formed by crushing a predetermined position of the sealing plate 10. For example, by compressing and crushing a predetermined position of the sealing plate 10 with a punch or the like using a press device to form a recess 18, the predetermined position of the sealing plate 10 can be made thinner than the surrounding sealing plate 10 (thin-walled). The method of forming the thin film portion 16 is not particularly limited.
[0016] As shown in Figures 4 and 9, a groove pattern 20 is formed on the surface of the thin film portion 16, having a first groove 31, a second groove 32, and a third groove 33 that rupture when the internal pressure of the sealed energy storage device 1 rises. The first groove 31, the second groove 32, and the third groove 33 constituting the groove pattern 20 prevent the sealed container 4 (see Figures 1 and 2) of the sealed energy storage device 1 from rupturing due to internal pressure when the internal pressure of the sealed energy storage device 1 rises to a predetermined pressure or higher. The grooves forming the groove pattern 20 can be formed, for example, by compression processing with a punch having a convex portion for forming grooves and a press device.
[0017] Figure 6 is a cross-sectional view of section VI-VI in Figure 5, Figure 7 is an enlarged view of section VII in Figure 6, and Figure 8 is an enlarged view of section VIII in Figure 7. When grooves are formed by the compression process described above, as shown in Figure 7, the thin film portion 16 around the grooves (first groove 31, third groove 33) becomes a roughly dome shape, raised in the direction in which the punch or the like is pressed. The method for forming each groove in the groove pattern 20 is not particularly limited.
[0018] <Details of the groove pattern 20 formed on the thin film portion 16 (Figure 9)> Next, using Figure 9, we will explain the details of each groove (first groove 31, second groove 32, third groove 33) that forms the groove pattern 20.
[0019] The first groove 31 is a single groove that extends in a straight line through approximately the center P of the thin film portion 16. Both the first end 31A and the other end 31B of the first groove 31 extend to just before the edge of the thin film portion 16. The first groove 31 also divides the thin film portion 16 into a first region 16A and a second region 16B.
[0020] The thin film portion 16 has two second grooves 32. One groove extends from one end 31A of the first groove 31 to the second region 16B of the thin film portion 16. The other groove extends from the other end 31B of the first groove 31 to the first region 16A of the thin film portion 16.
[0021] The thin film portion 16 has two third grooves 33. One groove extends from one end 31A of the first groove 31 to the first region 16A of the thin film portion 16. The other groove extends from the other end 31B of the first groove 31 to the second region 16B of the thin film portion 16.
[0022] Of the two second grooves 32, one has a first arc-shaped portion 32S that is convex toward the edge of the thin film portion 16, with the other groove 32S starting from one end 31A of the first groove 31 (second groove starting end 32A), and the other groove 32S starting from the other end 31B of the first groove (second groove starting end 32A). Each second groove 32 has a first straight portion 32T that extends linearly from the end 32B of the first arc portion 32S (end of the first arc portion) so as to be substantially parallel to the first groove 31. Each second groove 32 has a second arc-shaped portion 32U that extends toward the first groove 31 from the end 32C of the first straight portion 32T (end of the first straight portion). Each second groove 32 has a second straight section 32V that extends linearly from the end 32D (end of the second arc) of the second arc section 32U to just before the first groove 31, along a direction perpendicular to the first groove 31. The end of each second straight section 32V (end of the second straight section) is the end of each second groove 32, which is the second groove end 32Z. The positions of the second groove ends 32Z of the two second grooves 32 are opposite each other, with the approximate center P of the thin film section 16 in between.
[0023] Of the two third grooves 33, one starts at one end 31A of the first groove 31 (third groove starting end 33A), and the other starts at the other end 31B of the first groove (third groove starting end 33A), and each has a convex third arc portion 33S toward the edge of the thin film portion 16. Each third groove 33 has a third straight portion 33T that extends from the end 33B of the third arc portion 33S (third arc portion end) to just before the second groove 32 (second arc portion 32U), which is extended in a straight line substantially parallel to the first groove 31. The end of each third straight portion 33T (third straight portion end) is the end of each third groove 33, which is the third groove end 33Z.
[0024] Furthermore, each virtual straight line V1 passing through the position of the end of each third groove 33, which is the end of the third groove 33, and the end of the first straight section 32T of the second groove 32 adjacent to the first groove 31, which is the end of the first groove 31, is approximately perpendicular to the first groove 31. In other words, the position of the end of the third straight section 33T of the third groove 33 (third groove end 33Z) extends from the end 33B of the third arc section 33S to the position of the end of the first straight section 32T of the second groove 32 adjacent to the first groove 31, in a direction along the first groove 31 (a direction approximately parallel to the first groove 31).
[0025] Furthermore, as shown in Figure 9, the radius R2 of the second arc portion 32U is set to be smaller than the radius R1 of the first arc portion 32S (radius R2 < radius R1).
[0026] Furthermore, as shown in Figure 9, the distance D2 from the end of the second groove 32, which is the end of the second groove 32, to the first groove 31 is set to be shorter than the distance D3 from the end of the third groove, which is the end of the third groove, to the adjacent second groove 32 (up to the second arc portion 32U) in the direction along the first groove 31. Therefore, fracture in the groove due to pressure can be made easier.
[0027] <Position of the end of the second groove 32Z and the distance D4 from the end of the second groove 32Z to the center line H1 of the first groove (Figures 9, 11 to 13)> In Figure 9, if a line parallel to the first groove 31 passing through the center C1 of the first arc portion 32S or the center C3 of the third arc portion 33S is set as a virtual parallel line V2, then as shown in Figure 9, the position of the end of the second groove 32Z is located between the virtual parallel line V2 and the first groove 31.
[0028] Therefore, when the internal pressure of a sealed energy storage device increases, stress concentrates in such a way that the center of the explosion-proof valve becomes the starting point for opening (the position from which the valve opens). As a result, the valve opens from the center, making it easier to ensure robustness during opening (it becomes easier to open the valve from the same starting point regardless of the pressure at which it is opened).
[0029] Here, as shown in Figure 9, if the distance from the first groove center line H1, which is parallel to the first groove 31 and passes through the center of the first groove 31, to the end of the second groove 32Z is defined as distance D4, the inventors experimentally confirmed that the opening shape of the explosion-proof valve 15 changes depending on the length of distance D4. The inventors confirmed that the opening shape of the explosion-proof valve 15 when it opens will be one of the shapes (or a shape close to one of them) shown in Figure 11, namely "Pattern A," "Pattern B," or "Pattern C."
[0030] As an example of evaluating the opening of the explosion-proof valve 15, consider a case where the evaluation result is considered OK if both (1) and (2) below are satisfied. Note that "Pattern A," "Pattern B," and "Pattern C" shown in Figure 11 all satisfied (1) below. Furthermore, "Pattern A" also satisfied (2) below, but "Pattern B" sometimes did not satisfy (2), and "Pattern C" did not satisfy (2) below. Therefore, the evaluation result for "Pattern A" is OK, while the evaluation results for "Pattern B" and "Pattern C" are NG. Note that the length L1 in the X-axis direction of the groove pattern 20 shown in Figure 9 is, for example, about 21.8 [mm], and the length L2 in the Y-axis direction of the groove pattern 20 is, for example, about 14 [mm]. In this case, the area enclosed by the groove pattern 20 is approximately 284 [mm²]. ２ ]. (1) When the internal pressure of the sealed energy storage device 1 rises, the explosion-proof valve 15 opens when the internal pressure reaches 0.4 [MPa] to 0.6 [MPa]. (2) The opening area of the explosion-proof valve 15 after opening is 75 [mm²]. ２ That's all.
[0031] "Pattern A" shown in Figure 11 is a valve opening shape in which the first groove 31, the first arc portion 32S, and the third arc portion 33S split (break), while the first straight portion 32T, the third straight portion 33T, the second arc portion 32U, and the second straight portion 32V do not split (break).
[0032] In the case of "Pattern A," the length of distance D4 is an appropriate value (2.15 [mm] to 2.80 [mm] as described later), so that the valve opening starting point KA (see "Pattern A" in Figure 11), which is the starting point when the valve opens, is near the center P shown in Figure 9. Also, in the case of "Pattern A," stress is concentrated near the center P shown in Figure 9, and the magnitude of the concentrated stress is neither excessive nor insufficient, but of an appropriate size. As shown in Figure 11, the opening area MA of the hatched "Pattern A" is larger than the opening area MB of "Pattern B" and larger than the opening area MC of "Pattern C."
[0033] In "Pattern B" shown in Figure 11, one of the adjacent first and third arc sections 32S and 33S on one side splits (breaks). However, the adjacent first and third arc sections 32S and 33S on the other side do not split (break), and the first groove 31 does not split (break). Therefore, the valve shape is such that the first straight section 32T and the third straight section 33T on the split (break) side are split (broken) only partway.
[0034] In the case of "Pattern B," the length of distance D4 is excessive (longer than 2.80 [mm] as described later), so the valve opening starting point KB (see "Pattern B" in Figure 11), which is the starting point when the valve opens, is near one end 31A of the first groove (or the other end 31B of the first groove) as shown in Figure 9. Also, in the case of "Pattern B," the magnitude of the stress on the center P shown in Figure 9 is relaxed and becomes insufficient, the stress concentrated on one end 31A of the first groove becomes larger, and the valve opening starting point KB is near one end 31A of the first groove (or the other end 31B of the first groove). As shown in Figure 11, the opening area MB of the hatched "Pattern B" is smaller than the opening area MA of "Pattern A" and larger than the opening area MC of "Pattern C."
[0035] "Pattern C" shown in Figure 11 is a valve-opening shape in which the vicinity of the center of the first groove 31 bulges and cracks or fissures occur near the center of the first groove 31. In "Pattern C", the vicinity of the center of the first groove 31 is cracked (broken), while the positions of the first groove 31 away from the vicinity of the center, as well as the first arc portion 32S, the first straight portion 32T, the second arc portion 32U, the second straight portion 32V, the third arc portion 33S, and the third straight portion 33T are not cracked (broken).
[0036] In the case of "Pattern C," the length of distance D4 is too short (shorter than 2.15 [mm] as described later), so the valve opening starting point KC (see "Pattern C" in Figure 11), which is the starting point when the valve opens, is near the center P shown in Figure 9. Also, in the case of "Pattern C," stress concentrates near the center P shown in Figure 9, but because the length of distance D4 is too short, the magnitude of the stress concentrated at the valve opening starting point KC is excessive compared to the magnitude of the stress in the case of "Pattern A." As shown in Figure 11, the opening area MC of the hatched "Pattern C" is smaller than the opening area MA of "Pattern A" and smaller than the opening area MB of "Pattern B."
[0037] The inventor conducted numerous experiments using the actual device, changing the distance D4 to various values, and obtained the following experimental results as shown in Figure 12. (A) When the distance D4 was between 2.15 [mm] and 2.80 [mm], the explosion-proof valve 15 opened at 0.4 [MPa] to 0.6 [MPa], and only the opening shape of "Pattern A" occurred stably. Therefore, the evaluation result is OK (in "Pattern A", the opening area MA is 75 [mm] ２ (A) When the distance D4 is longer than 2.80 [mm], the explosion-proof valve 15 opens at 0.4 [MPa] to 0.6 [MPa], but the opening shape is "Pattern B" and the opening area is 75 [mm] ２ In some cases, the result was less than ]. Therefore, the evaluation result is NG. (C) When the distance D4 was shorter than 2.15 [mm], the explosion-proof valve 15 opened at 0.4 [MPa] to 0.6 [MPa], but the opening shape was "Pattern C" and the opening area was 75 [mm] ２ In some cases, the result was less than [ ]. Therefore, the evaluation result is NG.
[0038] As described above, in the technology of the present disclosure (the radius R2 of the second arc portion 32U shown in FIG. 9 is smaller than the radius R1 of the first arc portion 32S), as shown in FIG. 12, when the distance D4 is 2.15 [mm] to 2.80 [mm], the evaluation result was OK. In the conventional technology (the radius R2 of the second arc portion 32U is greater than or equal to the radius R1 of the first arc portion 32S), as shown in FIG. 12, the lower limit of the distance D4 at which the evaluation result is OK with a stable valve-opening shape of "Pattern A" is the same 2.15 [mm], but the upper limit is estimated to be a value shorter than 2.80 [mm].
[0039] Therefore, as shown in FIG. 12, the technology of the present disclosure (the radius R2 of the second arc portion 32U shown in FIG. 9 is smaller than the radius R1 of the first arc portion 32S) has a wider range in which the evaluation result is OK than the conventional technology (the radius R2 of the second arc portion 32U is greater than or equal to the radius R1 of the first arc portion 32S), and is effective. It is presumed that this is due to, for example, the length of the first straight portion 32T being shortened due to the large radius of the second arc portion 32U in the conventional technology.
[0040] Based on the above experimental results, the inventor determined that it is preferable to set the distance D4 to 2.15 [mm] to 2.80 [mm].
[0041] As a result, when the internal pressure of the container of the sealed power storage device rises, it is possible to appropriately concentrate stress at the valve-opening starting point (the position that becomes the starting point when the valve opens), and it is possible to avoid the stress from becoming too large. It is possible to open the valve at a desired valve-opening pressure (for example, 0.4 to 0.6 [MPa]), and it is possible to stably achieve the valve-opening shape of "Pattern A" shown in FIG. 11 so as to ensure a desired opening area (for example, 75 [mm ２ ]).
[0042] FIG. 13 is a graph showing the results of a simulation (CAE analysis (Computer Aided Engineering)) of the length of "distance D4" and the "central displacement amount" of the explosion-proof valve 15 (the displacement amount of the position of the center P in the state where the internal pressure of the container is atmospheric pressure and the state of 0.4 [MPa]) when the internal pressure of the sealed container 4 of the sealed power storage device 1 is gradually increased to 0.4 [MPa] without opening the valve.
[0043] As shown in Figure 13, for distances D4 shorter than 2.15 [mm] or longer than 2.80 [mm], where the evaluation result was NG, the central displacement was 0.500 [mm] or less. For distances D4 between 2.15 [mm] and 2.80 [mm], where the evaluation result was OK, the central displacement was 0.503 [mm] or more. Taking into account the results in Figure 13 and the margin, it is estimated that if the internal pressure of the container is 0.4 [MPa] and the explosion-proof valve 15 is not open, the evaluation result will be OK for distances D4 where the central displacement is greater than 0.500 [mm]. As shown in Figure 13, it is estimated that there is a correlation between the central displacement, the length of distance D4, and the evaluation result when the internal pressure of the container is 0.4 [MPa] (and the explosion-proof valve 15 is not open).
[0044] <Effects, etc.> As explained above, in the technology of this disclosure, the radius R2 of the second arc portion 32U shown in Figure 9 is set to be smaller than the radius R1 of the first arc portion 32S (radius R2 < radius R1). In contrast, in the conventional groove pattern 120 shown in Figure 10, the radius RY of the second arc portion 143 is set to be greater than or equal to the radius RX of the first arc portion 141 (radius RY ≥ radius RX). Therefore, the area of the first pressure-receiving portion 32P surrounded by the first groove 31 and the second groove 32 in Figure 9 is larger than the area of the area surrounded by the first groove 131 and the second groove 132 in Figure 10, which is the conventional groove pattern 120, and cracking can be achieved at a lower pressure. Furthermore, since the groove pattern 20 shown in Figure 9 does not have two intersecting straight lines, it is not necessary to consider the magnitude of residual stress generated at the intersection, and this does not lead to increased complexity in design and manufacturing.
[0045] Further, the position of the end (third groove end 33Z) of each third groove 33 shown in FIG. 9 is extended to the position of the end 32C of the first straight portion 32T of the second groove 32 adjacent to the first groove 31 across the first groove 31 in the direction along the first groove 31 (direction parallel to the first groove 31). Therefore, the third straight portion 33T of the third groove 33 is set to be longer. As a result, the area of the second pressure receiving portion 33P surrounded by the third groove 33 and the first groove 31 can be further increased, so that cracking can be performed at a lower pressure. Also, since the third straight portion 33T is made longer, the dome shape height of the second pressure receiving portion 33P becomes higher. Therefore, the area of the second pressure receiving portion 33P can be further increased, so that cracking can be performed at a lower pressure.
[0046] Further, in the technology of the present disclosure, it is set so that the distance D2 is shorter than the distance D3 (distance D2 < distance D3) in FIG. 9. Therefore, breakage at the groove portion due to pressure reception can be made easier.
[0047] <Others> The explosion-proof valve (thin film portion 16) of the sealed power storage device 1 of the technology disclosed in this specification is not limited to the configuration, structure, appearance, shape, etc. described in this embodiment, and various changes, additions, and deletions are possible without changing the gist of the technology disclosed in this specification.
[0048] The explosion-proof valve (thin film portion 16) described in this embodiment is not limited to application to the sealed power storage device 1, and is applicable to various sealed devices.
[0049] The embodiments described in detail with reference to the accompanying drawings are representative examples of the present invention and do not limit the present invention. The detailed description teaches those skilled in the art for creating, using, and / or implementing various aspects of the present teachings and does not limit the scope of the present invention. Further, each of the additional features and teachings described above can be applied and / or used separately or in combination with other features and teachings to provide an improved explosion-proof valve for a sealed power storage device and / or its manufacturing method and usage method.
Claims
1. An explosion-proof valve for a sealed energy storage device, wherein the explosion-proof valve comprises a thin-walled portion provided in the sealed container of the sealed energy storage device, which ruptures when the internal pressure of the sealed container rises, the thin-walled portion has a groove pattern that breaks when it ruptures, the groove pattern comprises a first groove, a second groove, and a third groove, the first groove is a straight line passing through approximately the center of the thin-walled portion, with both its one end and the other end extending to just before the edge of the thin-walled portion, dividing the thin-walled portion into a first region and a second region, the second groove is a groove extending from one end of the first groove to the second region of the thin-walled portion, and a groove extending from the other end of the first groove to the first region of the thin-walled portion, Each of the second grooves has a first arc portion, a first straight portion, a second arc portion, and a second straight portion, the first arc portion is an arc shape that is convex toward the edge of the thin film portion, with one end and the other end of the first groove as its starting points, the first straight portion extends linearly from the end of the first arc portion so as to be substantially parallel to the first groove, the second arc portion is an arc shape that is arc-shaped toward the first groove from the end of the first straight portion, the second straight portion extends linearly from the end of the second arc portion to just before the first groove, the end of the second straight portion is the end of the second groove, each of the third grooves has a third arc portion and a third straight portion, the third arc portion is an arc shape that is convex toward the edge of the thin film portion, with one end and the other end of the first groove as its starting points, The third straight section extends linearly from the end of the third arc section to just before the second arc section, substantially parallel to the first groove, the end of the third straight section is the end of the third groove, the end of the third groove extends in the direction along the first groove to the end of the first straight section of the second groove adjacent to the first groove, and the radius of the second arc section is smaller than the radius of the first arc section. This is an explosion-proof valve for a sealed energy storage device.
2. An explosion-proof valve for a sealed energy storage device according to claim 1, wherein the distance from the end of the second groove to the first groove is shorter than the distance from the end of the third groove to the adjacent second groove in the direction along the first groove.
3. An explosion-proof valve for a sealed energy storage device according to claim 1 or 2, wherein the end of the second groove is located between the first groove and a virtual parallel line passing through the center of the first arc portion or the center of the third arc portion and parallel to the first groove.
4. An explosion-proof valve for a sealed energy storage device according to claim 1 or 2, wherein the distance from the center line of the first groove, which is parallel to the first groove and passes through the center of the first groove, to the end of the second groove is 2.15 mm to 2.80 mm.