Gas exhaust device for power storage device

Abstract

The present invention provides a gas exhaust apparatus for an energy storage device, in which a cap member can be securely removed from a base member when a gas outlet of the energy storage device reaches or exceeds a predetermined value. The gas exhaust apparatus 10 for an energy storage device includes a base member 20, a cap member 60, and a seal member 80, the cap member 60 having a lid part 61, a pressing part 67, a pair of elastic pieces 69, 69, and a claw part 71, wherein the claw part 71 engages a mating part 41 with the elastic pieces 69 flexed outward, and a pair of first guide parts 51, 51 and a pair of second guide parts 53, 53 are provided on the circumference of a cylindrical part 21, the second guide parts 53 being located more radially inward of the cylindrical part 21 than the first guide parts 51 and further guiding the elastic pieces 69 guided by the first guide parts 51 when the cap member is mounted.

Description

[Technical Field]

[0001] The present invention relates to a gas discharge device for an electricity storage device, which discharges gas when the gas pressure at a gas discharge port of the electricity storage device is equal to or greater than a predetermined value. [Background technology]

[0002] For example, hybrid vehicles and electric vehicles use electricity storage devices such as batteries and capacitors. In the case of batteries such as lithium-ion batteries, gas may be generated due to a chemical reaction in the electrolyte. In this case, it is necessary to vent the gas from inside the electricity storage device to the outside of the electricity storage device.

[0003] For example, Patent Document 1 listed below describes a sealed lead-acid battery having a cylindrical liquid filling port protruding upward from an inner lid of the battery, and a cap valve removably attached to the outer periphery of the upper part of the liquid filling port, the cap valve having a circular plate-shaped ceiling plate and a peripheral wall hanging down from the peripheral edge of the ceiling plate.

[0004] The upper outer periphery of the filling port is provided with a protrusion having a tapered outer surface and a horizontal locking surface formed on its lower end surface. The inner periphery of the lower end of the peripheral wall of the cap valve is also provided with a protrusion having a tapered outer surface and a horizontal locking surface formed on its upper end surface. By placing the cap valve over the upper outer periphery of the filling port, the locking surface of the protrusion on the filling port side and the locking surface of the protrusion on the cap valve side engage with each other, thereby attaching the cap valve to the filling port. When the gas pressure inside the lead-acid battery reaches or exceeds a predetermined value, the cap valve detaches from the filling port, allowing gas inside the lead-acid battery to be discharged.

[0005] In the sealed lead-acid battery of Patent Document 1, it may be desirable to improve the sealing between the filler port and the cap valve. In this case, for example, a circular seal ring may be disposed between the locking surface of the protrusion on the filler port side and the locking surface of the protrusion on the cap valve side. The seal ring disposed in this manner is pressed by both the locking surfaces on the filler port side and the cap valve side and becomes deformed, thereby sealing the gap between the filler port and the cap valve. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 8-315799 Summary of the Invention [Problem to be solved by the invention]

[0007] In the sealed lead-acid battery, the cap valve is typically attached to the upper periphery of the filler port so that its center is aligned with the center of the filler port, as shown in FIG. 1 of Patent Document 1. However, the cap valve may be attached to the upper periphery of the filler port with its center misaligned with the center of the filler port. In such cases, if a seal ring is disposed between the locking surface of the protrusion on the filler port side and the locking surface of the protrusion on the cap valve side, the seal ring will be pressed by both locking surfaces and deform unevenly. As a result, areas with high and low sealing pressure will be created, causing gas to leak from the areas with low sealing pressure. This could prevent the cap valve from being removed from the filler port even when the gas pressure in the lead-acid battery exceeds a predetermined value.

[0008] Therefore, an object of the present invention is to provide a gas discharge device for an electricity storage device that can reliably remove a cap member from a base member when the gas discharge port of the electricity storage device reaches a predetermined value or more. [Means for solving the problem]

[0009] In order to achieve the above object, the present invention provides a gas discharge device for an electricity storage device that discharges gas when gas pressure at a gas discharge port of the electricity storage device is equal to or higher than a predetermined value, the gas discharge device comprising: a base member that is fixed to the gas discharge port and has a cylindrical portion that has a passage formed therein that communicates with the gas discharge port and an engaged portion that is provided on the outer periphery of the cylindrical portion; a cap member that is detachably attached to the base member so as to close an outlet of the passage; and a sealing member that is disposed between the base member and the cap member, the cap member having a lid portion, a pressing portion that is provided on the lid portion and that presses the sealing member, a pair of elastic pieces that extend from positions that are opposite to each other in the circumferential direction of the lid portion, and claw portions that are formed on each elastic piece and that engage with and disengage from the engaged portion, and in a state where the pair of elastic pieces are flexibly deformed outward, the claw portions engage with the engaged portion, and when the gas pressure at the gas discharge port is equal to or higher than a predetermined value, the cap member closes the lid portion and a pair of second guide portions are provided on the outer periphery of the cylindrical portion, the pair of first guide portions being located on both sides of the elastic piece in the width direction and positioned radially inward of the cylindrical portion relative to the pair of first guide portions, the pair of second guide portions being located on both sides of the elastic piece in the width direction and positioned radially inward of the cylindrical portion relative to the pair of first guide portions, the pair of second guide portions being located on both sides of the elastic piece in the width direction and further guiding the elastic piece guided by the first guide portions during the attachment, and the relationship L1 > L2 > L3 is established, where L1 is the gap between the pair of first guide portions, L2 is the gap between the pair of second guide portions, and L3 is the width direction length of the elastic piece. [Effects of the Invention]

[0010] According to the present invention, when the cap member is attached to the base member, the pair of elastic pieces, which engage with each other while being bent outward, guide the opposing direction of the pair of elastic pieces. Furthermore, the elastic pieces, guided by the first guide portion, are further guided by the second guide portion, thereby guiding the direction intersecting the opposing direction of the pair of elastic pieces. This facilitates aligning the center of the seal member with the center of the lid portion of the cap member, thereby preventing the pressing portion provided on the lid portion from biting into the seal member in a displaced state, resulting in uneven deformation of the seal member. As a result, when the gas pressure at the gas outlet exceeds a predetermined value and the engagement of the claw portion with the engaged portion is released, the cap member can be reliably removed from the base member. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is an exploded perspective view showing one embodiment of a gas discharge device for an electricity storage device according to the present invention. [Figure 2] 3 is a perspective view of the gas discharge apparatus for the electricity storage device in an assembled state. FIG. [Figure 3] 2 is a perspective view of a base member constituting the gas discharge device for the electricity storage device, seen from a direction different from that in FIG. 1. FIG. [Figure 4] FIG. 4 is an enlarged perspective view of a main part of FIG. 3. [Figure 5] 3 is a front view of a base member constituting the gas discharge apparatus for an electricity storage device according to the present invention. FIG. [Figure 6] FIG. 6 is an enlarged view of part A in FIG. 5. [Figure 7] 3 is a side view of a base member constituting the gas discharge apparatus for an electricity storage device according to the present invention. FIG. [Figure 8] FIG. 8 is an enlarged view of part B in FIG. 7. [Figure 9] FIG. 2 is a vertical cross-sectional view of the gas discharge device for the electricity storage device. [Figure 10] 10 is a vertical cross-sectional view of the gas discharge device for the electricity storage device, taken in a direction different from that of FIG. 9. [Figure 11]11 is an explanatory vertical cross-sectional view of the state in which the cap member is detached from the base member in the state of FIG. 10. FIG. [Figure 12] FIG. 2 is a cross-sectional view of the gas discharge device for the electricity storage device. [Figure 13] FIG. 13 is an enlarged view of part D in FIG. [Figure 14] 12, in which the pressing portion of the cap member is engaged without being displaced relative to the sealing member; FIG. 12, in which the pressing portion of the cap member is engaged with the sealing member while being displaced relative to the sealing member; and FIG. 12, in which the pressing portion of the cap member is engaged with the sealing member while being displaced relative to the sealing member; and FIG. 12, in which the second guide portion is not present. [Figure 15] 10A and 10B show the process of attaching a cap member to a base member, where (a) is an explanatory diagram of the state in which the claw portion of the elastic piece is received in the receiving recess, and (b) is an explanatory diagram of the state in which the claw portion is engaged with the engaged portion. [Figure 16] FIG. 2 is a perspective view illustrating a location where the gas discharge device for an electricity storage device according to the present invention is used. DETAILED DESCRIPTION OF THE INVENTION

[0012] (One embodiment of a gas discharge device for an electricity storage device) DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a gas discharge apparatus for an electricity storage device according to the present invention will now be described with reference to the drawings.

[0013] As shown in FIG. 16, this gas discharge device 10 for an electricity storage device (hereinafter also simply referred to as "discharge device 10") is for discharging gas G when the gas pressure at the gas discharge port 6 (see FIGS. 9 to 11) of the electricity storage device 1 is equal to or greater than a predetermined value.

[0014] In this embodiment, a plurality of electricity storage devices 1 are arranged inside the case 2. Here, two electricity storage devices 1 are arranged in each of the left and right regions of the case 2. A connector 3 that communicates with the internal space of each electricity storage device 1 is attached to each electricity storage device 1. The pair of electricity storage devices 1, 1 arranged in the left and right regions of the case 2, respectively, are connected to a common gas exhaust tube 4 via the connectors 3, 3.

[0015] The gas exhaust tubes 4 extend outward from the case 2 via tube holding members 5 made of rubber, sponge, or the like. That is, the gas exhaust tubes 4 extend outward from the left and right side walls of the case 2.

[0016] 9 to 11, a gas exhaust port 6 is provided at the tip of each gas exhaust tube 4 in the extending direction. In this embodiment, the gas exhaust port 6 is arranged so that its opening faces downward. Also, a mounting member 7 having a mounting hole 7a is arranged in a position opposite the gas exhaust port 6, and a discharge device 10 is attached to the mounting hole 7a of the mounting member 7 (see FIGS. 9 to 11).

[0017] Examples of the above-mentioned electricity storage device 1 include batteries (lithium ion batteries, etc.), condensers, and the like used in hybrid vehicles including plug-in hybrid vehicles, electric vehicles, etc., but are not particularly limited as long as they are devices capable of storing electricity. Furthermore, there are no particular limitations on the shape and structure of the case, or the shape and number of electricity storage devices arranged in the case.

[0018] As shown in Figures 1, 2 and 9 to 11, the exhaust device 10 in this embodiment includes a base member 20 that is fixed to the gas exhaust port 6 and has a cylindrical portion 21 that has a passage 23 formed therein that communicates with the gas exhaust port 6 and an engaged portion 41 that is provided on the outer periphery of the cylindrical portion 21, a cap member 60 that is detachably attached to the base member 20 so as to close the outlet 23b of the passage 23, and a seal member 80 that is arranged between the base member 20 and the cap member 60 and seals the gap therebetween.

[0019] The cap member 60 also has a lid portion 61, a pressing portion 67 provided on the lid portion 61 and pressing the sealing member 80, a pair of elastic pieces 69, 69 extending from opposite positions circumferentially of the lid portion 61, and a claw portion 71 formed on each elastic piece 69 that engages with and disengages from the engaged portion 41.

[0020] The cap member 60 is attached to the base member 20 by pushing it toward the outlet 23b of the passage 23 of the cylindrical portion 21 constituting the base member 20 and engaging the claw portions 71, 71 of the pair of elastic pieces 69, 69 with the pair of engaged portions 41, 41 of the base member 20 (see FIG. 10). At this time, the direction in which the cap member 60 is pushed into the base member 20 and attached to the base member 20 is referred to as the "attachment direction F1 of the cap member 60" or the "cap member attachment direction F1" (see FIG. 1).

[0021] Furthermore, as shown in Figures 9 and 10, the sealing member 80 is fitted onto the cylindrical portion 21 of the base member 20 while being pressed by the pressing portion 67 of the cap member 60, thereby sealing the gap between the base member 20 and the cap member 60.

[0022] Furthermore, the discharge device 10 has a seal washer 8 that is attached to the base member 20 and seals the gap between the mounting hole 7 a of the mounted member 7 and the base member 20 .

[0023] The above-mentioned seal member 80 and seal washer 8 are annular and made of a porous material such as sponge, or an elastic material such as rubber or elastic elastomer. The seal member 80 can be deformed by being pressed axially and compressed by an external force, gas pressure, etc., to reduce its thickness, by being pressed radially inward to expand, or by being pressed radially outward to reduce its diameter. The seal member 80 has a smaller diameter than the seal washer 8.

[0024] Next, the detailed structure of the base member 20 will be described with reference to FIG. 1 and FIGS.

[0025] As shown in Figures 9 to 11, the base member 20 of this embodiment has a tubular portion 21 having a passage 23 formed therein and having a generally cylindrical shape as a whole. An annular flange portion 25 extends from the outer periphery of the tubular portion 21 midway in the axial direction. When the base member 20 is attached to the attachment hole 7a of the attachment workpiece 7, the flange portion 25 sandwiches the seal washer 8 between the attachment workpiece 7 and the attachment workpiece 7 (see Figures 9 to 11). Furthermore, the proximal end (one end) of the tubular portion 21 in the extending direction forms a connecting portion 27, and the distal end (the other end) of the tubular portion 21 in the extending direction forms an insertion portion 29.

[0026] In the following description, the tip side of the tubular portion 21 refers to the end side where the cap member 60 is arranged, and the base side of the tubular portion 21 refers to the end side opposite the tip side where the gas exhaust port 6 is arranged.

[0027] Furthermore, by inserting the connection portion 27 into the gas exhaust port 6 of the gas exhaust tube 4, the base member 20 is connected and fixed to the gas exhaust port 6. On the other hand, the insertion portion 29 is inserted into the mounting hole 7a of the mounted member 7 and is projected from an opening on the back side of the mounting hole 7a (the side opposite to the front side, which is the surface facing the flange portion 25).

[0028] Furthermore, the base end opening of the passage 23 formed in the cylindrical portion 21 on the connecting portion 27 side serves as an inlet 23a for gas G flowing into the passage 23 via the gas exhaust tube 4. Furthermore, the tip end opening of the passage 23 on the insertion portion 29 side serves as an outlet 23b for gas G flowing out of the passage 23.

[0029] Furthermore, as shown in Figures 3 and 10, an annular protrusion 31 is provided on the outer periphery of the insertion portion 29 slightly closer to the base end than the tip end, protruding radially outward from the tubular portion 21.

[0030] 3, a pair of thin-plate-like guide walls 33, 33 arranged parallel to each other extend from two circumferentially opposing positions on the annular protrusion 31 along the axial direction of the tubular portion 21. That is, a total of four guide walls 33 are provided on the tubular portion 21, one pair at each circumferentially opposing position on the annular protrusion 31 (see FIG. 5). One end of each of the extending guide walls 33 is connected to the rear side of the flange portion 25 (see FIG. 10).

[0031] Furthermore, as shown in Figure 3, an arc-shaped sealing member retaining wall 35 extends along the axial direction of the tubular portion 21 from the outer peripheral edge of the annular protrusion 31, except for the area where the pair of guide wall portions 33, 33 are provided.

[0032] 9, a seal member mounting groove 37 having a generally annular groove shape is formed between the annular protrusion 31, the seal member holding wall 35, and the tip end portion of the insertion portion 29 of the cylindrical portion 21. A seal member 80 is inserted into and held in this seal member mounting groove 37, and is mounted (exterior mounted) on the outer periphery of the cylindrical portion 21. In addition, the seal member holding wall 35 restricts the seal member 80 from expanding radially outward.

[0033] 3, a seal member holding projection 39 is provided on the outer periphery of the tip end of the insertion portion 29 of the cylindrical portion 21, between the pair of guide wall portions 33. In this embodiment, a pair of seal member holding projections 39 is provided at two opposing locations in the circumferential direction of the cylindrical portion 21 (see FIG. 5). This pair of seal member holding projections 39 holds the seal member 80 attached to the seal member attachment groove 37 so as to prevent it from coming off (see FIG. 10).

[0034] Further, the outer peripheral edge of the annular protrusion 31, the portion between the pair of guide wall portions 33, 33, forms an engaged portion 41 (see FIG. 3). In this embodiment, a pair of engaged portions 41, 41 are provided at two circumferentially opposing positions of the annular protrusion 31.

[0035] 8 and 10, the surface of each engaged portion 41 that is adjacent to the flange portion 25 (the surface on the side in the cap member mounting direction F1) forms an engaged surface 42. As shown in the partially enlarged view of Fig. 10, this engaged surface 42 is made up of a horizontal surface 42a (a surface perpendicular to the axis of the base member 20) that is a flat horizontal surface, and a curved surface 42b that is located radially outward from the horizontal surface 42a and has a curved surface shape.

[0036] As shown in FIG. 10, the claw portions 71, 71 of the pair of elastic pieces 69, 69 of the cap member 60 are adapted to engage with the engaged surfaces 42, 42 of the pair of engaged portions 41, 41.

[0037] Also, as shown in Figures 4 and 6, the surface 43 of the engaged portion 41 that faces the inner circumference of the elastic piece 69 (hereinafter also simply referred to as the "facing surface 43") has a top 43a and a curved surface 43b that gradually becomes lower in directions that move away from the top 43a in the circumferential direction of the tubular portion 21.

[0038] More specifically, the opposing surface 43 of the engaged portion 41 has an arc-shaped rounded apex 43a located in the circumferential center of the engaged portion 41, and convex curved surfaces 43b, 43b that gradually become lower from this apex 43a in directions away from each other in the circumferential direction of the tubular portion 21, in this case towards both sides of the width of the engaged portion 41 (see Figure 4).

[0039] 3, a thin plate-like protruding piece 44 protrudes radially outward from the outer periphery of the annular protrusion 31, and an outer periphery wall 45 is provided on the outer periphery of the protruding piece 44, extending in the axial direction of the tubular portion 21. The outer periphery wall 45 has an arc-shaped portion 45a that is arc-shaped to fit the outer periphery of the annular protrusion 31, and flat portions 45b, 45b that are parallel to each other. Furthermore, the outer periphery wall 45 is cut out at the locations where the pair of engaged portions 41, 41 are located (see FIG. 5), allowing the pair of elastic pieces 69, 69 of the cap member 60 to fit between the pair of guide wall portions 33, 33.

[0040] 3 and 7, a pair of flexible engaging pieces 47 extend obliquely outward from the outer surfaces of the tip ends of the pair of flat portions 45b of the outer peripheral wall portion 45 toward the flange portion 25. When viewed from the axial direction of the tubular portion 21, the pair of engaging pieces 47 are arranged perpendicular to the pair of engaged portions 41 (see FIG. 5). Furthermore, as shown in FIG. 7, a tapered engaging surface 47a is formed on the outer surface of the tip end of each engaging piece 47 in the extending direction.

[0041] As shown in Figure 9, the engaging surfaces 47a of each engaging piece 47 engage with the rear peripheral edge of the mounting hole 7a of the mounting member 7, thereby fixing the base member 20 to the mounting hole 7a via the pair of engaging pieces 47, 47, and ultimately attaching the entire discharge device 10 to the mounting member 7.

[0042] As shown in Figures 3 to 8, the outer periphery of the cylindrical portion 21 is provided with a pair of first guide portions 51, 51 located on both widthwise sides of the elastic piece 69 of the cap member 60 and guiding the cap member 60 when it is attached to the base member 20, and a pair of second guide portions 53, 53 located on both widthwise sides of the elastic piece 69 and radially inward of the cylindrical portion 21 relative to the pair of first guide portions 51, 51, and further guiding the elastic piece 69 guided by the pair of first guide portions 51, 51 when it is attached to the base member 20.

[0043] The width direction of the elastic piece 69 means a direction perpendicular to the direction of bending deformation of the elastic piece 69 (see arrow T in Figure 10) and along the circumferential direction of the cylindrical portion 21 of the base member 20 and the peripheral wall 65 (described later) of the lid portion 61 of the cap member 60.

[0044] As shown in Figures 4 and 8, a pair of rib-shaped protrusions 49, 49 are protruded from the inner surface of the base end portion 33a (the end portion close to the seal member holding wall 35) in the protruding direction of the pair of guide wall portions 33, 33, at a location located on the opposite side of the cap member mounting direction F1 from the engaged portion 41.

[0045] 4 and 6, when the cylindrical portion 21 is viewed in the axial direction, the surfaces of the pair of rib-like protrusions 49, 49 on the tip side away from the cylindrical portion 21, in other words, the surfaces of the pair of rib-like protrusions 49, 49 facing the tip side in the protruding direction of the guide wall portion 33, form the pair of first guide portions 51, 51. The pair of first guide portions 51, 51 also have tapered surfaces that are inclined so as to gradually narrow radially inward of the cylindrical portion 21.

[0046] Furthermore, as shown in Figures 4 and 6, when the tubular portion 21 is viewed from the axial direction, the surfaces of the pair of rib-shaped protrusions 49, 49 on the base end side close to the tubular portion 21, in other words, the surfaces of the pair of rib-shaped protrusions 49, 49 that are located radially inward of the tubular portion 21 and facing each other form the pair of second guide portions 53, 53.

[0047] That is, the pair of second guide portions 53, 53 are provided at locations closer to the radial inside of the cylindrical portion 21 than the pair of first guide portions 51, 51. The pair of second guide portions 53, 53 have flat surfaces parallel to each other. Furthermore, the tip (upper end) of the second guide portion 53 is formed continuous with the base end (lower end) of the first guide portion 51 via an R-shaped boundary portion 53a. In other words, the second guide portion 53 is provided at a position that is one step lower than the first guide portion 51 via the boundary portion 53a.

[0048] 13 also shows the relationship between the first guide portion 51, the second guide portion 53, and the elastic piece 69. That is, when the gap between the pair of first guide portions 51, 51 (the maximum gap between the pair of first guide portions 51, 51) is L1, the gap between the pair of second guide portions 53, 53 (the minimum gap between the pair of second guide portions 53, 53) is L2, and the width direction length of the elastic piece 69 is L3, they are set so that L1 > L2 > L3.

[0049] 6 shows a state in which the elastic piece 69 is misaligned in the circumferential direction of the tubular portion 21 with respect to the engaged portion 41 when the cap member 60 is attached to the base member 20 (see the elastic piece 69' indicated by the two-dot chain line). Even in this state, the pair of first guide portions 51, 51 and the pair of second guide portions 53, 53 correct the misalignment of the elastic piece 69, so that the claw portion 71 engages with a predetermined position on the engaged portion 41. Details of the process of guiding the elastic piece 69 by the first guide portion 51 and the second guide portion 53 will be described later.

[0050] The engaged portion 41 will be further described in relation to the first guide portion 51 and the second guide portion 53. That is, in this embodiment, the engaged portion 41 is provided at a portion opposite to the mounting direction F1 of the cap member 60 relative to the base member 20 with a receiving recess 55 that receives the claw portion 71 of the elastic piece 69 guided by the second guide portion 53 (see FIG. 15(a)).

[0051] More specifically, as shown in Figure 4, a receiving recess 55 is provided on the engaged portion 41 on the opposite side of the mounting direction F1 of the cap member 60 relative to the base member 20, between the second guide portions 53, 53 provided on a pair of rib-shaped protrusions 49, 49, and is open upward (in the direction facing radially outward of the tubular portion 21) and on one side.

[0052] 6, the receiving recess 55 has a flat bottom surface 55a, and the pair of second guide portions 53, 53 are arranged on both sides of the bottom surface 55a in the width direction, with R-shaped corner portions 55b, 55b interposed between them. That is, the pair of second guide portions 53, 53 form the inner surfaces of the receiving recess 55 in the width direction.

[0053] Furthermore, as shown in Figure 8, when the cylindrical portion 21 is viewed from the radial direction, the outer surfaces 57, 57 of the pair of rib-shaped protrusions 49, 49 on the cap member mounting direction F1 side are tapered surfaces that gradually widen toward the cap member mounting direction F1 side.

[0054] Next, the detailed structure of the cap member 60 that is detachably attached to the base member 20 will be described with reference to FIGS. 1, 9, 10, etc.

[0055] As described above, the cap member 60 of this embodiment has the lid portion 61, the pressing portion 67, a pair of elastic pieces 69, 69, and the claw portions 71 formed on each elastic piece 69.

[0056] Furthermore, the lid portion 61 in this embodiment is composed of a bottom wall 63 in the shape of a substantially circular plate, and a peripheral wall 65 in the shape of a substantially cylindrical wall erected from the outer periphery of the bottom wall 63. As shown in Fig. 10, the bottom wall 63 constituting the lid portion 61 is disposed opposite the outlet 23b of the passage 23, and serves as a portion that receives the gas G flowing out from the outlet 23b of the passage 23 (this can also be said to be a portion on which the pressure of the gas G at the gas outlet 6 acts).

[0057] Furthermore, the cap member 60 is configured such that when the pair of elastic pieces 69, 69 are bent and deformed outward, the claw portions 71, 71 of each elastic piece 69 engage with the pair of engaged portions 41, 41, respectively, and when the gas pressure at the gas exhaust port 6 is equal to or greater than a predetermined value, the pressure received by the lid portion 61 causes the engagement of each claw portion 71 with the engaged portion 41 to be released, causing the cap member 60 to detach from the base member 20.

[0058] Furthermore, a pressing portion 67 having an annular protrusion shape protrudes from the inner peripheral edge of a tip surface 65a in the erecting direction of the peripheral wall 65 of the lid portion 61. This pressing portion 67 can be inserted into the seal member attachment groove 37 of the base member 20 when the cap member 60 is attached to the base member 20 (see FIG. 9).

[0059] When the cap member 60 is pressed against the base member 20 in the cap member mounting direction F1 to mount the cap member 60 on the base member 20, the pressing portion 67 presses the seal member 80 mounted in the seal member mounting groove 37 from the axial direction. As a result, the seal member 80 is compressed and deformed so as to expand radially outward, but this expansion is restricted by the seal member retaining wall 35 (see FIG. 9).

[0060] A pair of elastic pieces 69, 69 extend from the outer peripheral edge of the lid portion 61 at two radially opposing locations. Each elastic piece 69 has a base end (fixed end) connected to the inner peripheral edge of the tip surface 65a of the peripheral wall 65 that constitutes the lid portion 61, and is a strip-shaped piece that extends beyond the tip of the pressing portion 67.

[0061] Furthermore, the tip of each elastic piece 69 in the extension direction is a free end, and is capable of being flexibly deformed inward or outward of the cap member 60, as shown by arrow T in Fig. 10. The width of each elastic piece 69 in the circumferential direction is narrower than the distance between the pair of guide wall portions 33, 33 of the base member 20, and is therefore capable of fitting between the pair of guide wall portions 33, 33 when the cap member 60 is attached to the base member 20.

[0062] Furthermore, a claw portion 71 protrudes from the inner periphery of the tip end in the extension direction of each elastic piece 69. Referring also to the partial enlarged view of Fig. 10, this claw portion 71 has an apex 72 that protrudes most from the inner periphery of the elastic piece 69, a tapered surface 73 that is formed on the outer surface on the attachment direction F1 side of the cap member 60 (the side away from the lid portion 61) and has an inclined surface shape such that the amount of protrusion from the apex 72 gradually decreases toward the tip end in the extension direction of the elastic piece 69, and an engagement surface 74 that is formed on the outer surface on the opposite side to the tapered surface 73 (the opposite side to the cap member attachment direction F1) and has an inclined surface shape such that the amount of protrusion from the apex 72 gradually decreases toward the base end in the extension direction of the elastic piece 69.

[0063] The claw portions 71 are formed over the entire circumferential (widthwise) area of ​​the elastic piece 69 (see FIG. 1). Therefore, when the elastic piece 69 is guided by the first guide portion 51 and the second guide portion 53, the claw portions 71 mainly come into contact with the first guide portion 51 and the second guide portion 53.

[0064] Next, the process of attaching the cap member 60 having the above structure to the base member 20 will be described together with the process of guiding the elastic piece 69 by the first guide portion 51 and the second guide portion 53.

[0065] First, as shown in Fig. 1, one elastic piece 69 is aligned between one of the guide wall portions 33, 33, and the other elastic piece 69 is aligned between the other of the guide wall portions 33, 33. Thereafter, the cap member 60 is pushed into the base member 20 in the cap member mounting direction F1 in Fig. 1.

[0066] At this time, it is desirable that the elastic piece 69 is positioned so that it can be inserted between the pair of second guide portions 53, 53, as shown in Fig. 13, but the elastic piece 69 is often misaligned to one side in the circumferential direction of the tubular portion 21 (see the elastic piece 69' indicated by the two-dot chain line in Fig. 6). In this case, the claw portion 71 does not engage with the engaged portion 41 at a predetermined position.

[0067] Even in the above case, in the discharge device 10 of the present invention, the positional deviation of the elastic piece 69 in the circumferential direction of the cylindrical portion 21 is corrected, and the claw portion 71 can engage with the predetermined position of the engaged portion 41.

[0068] That is, as described above, when the cap member 60 is pushed into the base member 20 with the elastic piece 69 misaligned to one side in the circumferential direction of the tubular portion 21 (see the elastic piece 69' indicated by the dotted line), the claw portion 71 provided at the tip of the elastic piece 69 and formed across the entire width of the elastic piece 69 comes into contact with one of the first guide portions 51 (one widthwise side portion of the claw portion 71 abuts against one of the first guide portions 51).

[0069] As a result, the claw portion 71 is pressed against one of the first guide portions 51, causing the elastic piece 69 to be pushed apart and bent outward from the cap member 60. As shown in FIG. 6, an elastic restoring force F2 acting radially inward of the tubular portion 21 acts on the elastic piece 69, but this elastic restoring force F2 is converted into a force F3 in the lateral direction (a direction perpendicular to the elastic restoring force F2) by the one of the first guide portions 51, which has a tapered surface.

[0070] As a result, one of the first guide portions 51 guides the elastic piece 69 to move circumferentially (laterally) toward the other first guide portion 51, thereby correcting the positional deviation of the elastic piece 69 in the circumferential direction of the tubular portion 21, and ultimately correcting the positional deviation of the claw portion 71 relative to the engaged portion 41.

[0071] Furthermore, the elastic piece 69, whose positional deviation has been corrected by the first guide portion 51, enters (falls) between the pair of second guide portions 53, 53 due to its elastic restoring force F2. At this time, if the elastic piece 69 is misaligned in one direction in the circumferential direction of the tubular portion 21, for example, one widthwise side portion of the claw portion 71 abuts against one of the second guide portions 53. Then, the claw portion 71 is pressed by one of the second guide portions 53, and the elastic piece 69 is guided to move in the circumferential direction toward the other second guide portion 53, while entering between the pair of second guide portions 53, 53 (elastic piece 69'' indicated by the two-dot chain line in FIG. 6). As a result, the positional deviation of the elastic piece 69 in the circumferential direction of the tubular portion 21 is further corrected, and the positional deviation of the claw portion 71 relative to the engaged portion 41 is also further corrected.

[0072] In this way, in the discharge device 10, the two guide portions, the first guide portion 51 and the second guide portion 53, are configured to correct the positional deviation of the elastic piece 69 in the circumferential direction of the cylindrical portion 21.

[0073] 6, the second guide portion 53 has a flat surface and is provided at a position one step lower than the first guide portion 51 via a boundary portion 53a, so that the difference in the inclination angle with respect to a line segment L along the arrangement direction of the pair of guide walls 33, 33 is clear. Therefore, a corner portion 69a in the width direction of the elastic piece 69 guided by the first guide portion 51 (the lower corner portion of the elastic piece 69'' in FIG. 6) is structured to reliably abut against the second guide portion 53.

[0074] If the second guide portion 53 does not exist and the first guide portion 51 is connected to the bottom surface 55a of the receiving recess 55 via multiple R-shaped portions 51a, 51b, as shown in Figure 14(c), it becomes difficult to guide the widthwise corner portion 69a of the elastic piece 69 (the corner portion 69a of the elastic piece 69 is located in the R-shaped portion 51a of the first guide portion 51, making it difficult to guide).

[0075] Furthermore, when the elastic piece 69 enters between the pair of second guide portions 53, 53, the top portion 72 of the claw portion 71 is received in the receiving recess 55 provided in the engaged portion 41, as shown in Figure 15(a).

[0076] From this state, when the cap member 60 is further pressed into the base member 20, the top 72 of the claw portion 71 comes out of the receiving recess 55, and the top 72 comes into sliding contact with the top 43a of the opposing surface 43 of the engaged portion 41. Then, when the claw portion 71 climbs over the engaged portion 41 and the engaging surface 74 reaches the engaged surface 42, the elastic piece 69 elastically returns, and the engaging surface 74 of the claw portion 71 engages with the engaged surface 42 of the engaged portion 41, as shown in Figure 15(b).

[0077] 10, the cap member 60 is attached to the base member 20 via the pair of elastic pieces 69, 69 and their claw portions 71, 71. In this state, the engaged surface 42 of the base member 20 and the claw portion 71 of the cap member 60 are arranged diagonally.

[0078] In this embodiment, the claw portion 71 is provided with an inclined engaging surface 74, and the engaging surface 74 is engaged with the engaged surface 42, including the curved surface 42b, of the base member 20. This reduces the engaging force of the cap member 60 with the base member 20 compared to when the engaging surface and the engaged portion of the claw portion are both horizontal and engage with each other. Therefore, when the gas pressure at the gas discharge port 6 reaches a predetermined value or higher and the gas G flowing into the passage 23 from the inlet 23a of the base member 20 and flowing out from the outlet 23b also reaches a predetermined value or higher, the pair of elastic pieces 69, 69 are each flexibly deformed outward via the lid portion 61 of the cap member 60, which is pressed by the gas G, and the engagement of the claw portion 71 with the engaged surface 42 of the base member 20 is released, and the cap member 60 is configured to be detached from the base member 20.

[0079] As described above, when the top 72 of the claw portion 71 overcomes the engaged portion 41 and elastically returns to its original state, each elastic piece 69 does not completely return to a state in which it is not bent outward from the cap member 60, but rather the claw portion 71 engages with the engaged surface 42 while maintaining a state in which it is slightly bent outward from the cap member 60.

[0080] (Variation) In the embodiment described above, the shapes, structures, layouts, etc. of the electricity storage device, case, gas exhaust tube, tube holding member, gas exhaust port, etc. are not limited to the above-described embodiments. For example, in this embodiment, two electricity storage devices 1 are used as a set, but three or more electricity storage devices may be used as a set and connected via connectors or tubes. Furthermore, the gas exhaust port 6 is an opening facing downward, but it may also be an opening facing sideways.

[0081] Furthermore, the shapes and structures of the base member, cap member, seal member, seal washer, and the like that constitute the gas discharge device for an electricity storage device are not limited to the above-described embodiments.

[0082] For example, base member 20 has tubular portion 21 that has connecting portion 27 and insertion portion 29 and is generally cylindrical overall, but this tubular portion may be, for example, generally rectangular or elliptical, as long as it is fixed to the gas exhaust port and has a passage therein that communicates with the gas exhaust port. Also, base member 20 in this embodiment is configured so that connecting portion 27 is inserted into and fixed to gas exhaust port 6 of gas exhaust tube 4, but a tube may be inserted into the base member and the base member may be fixed to the gas exhaust port.

[0083] Furthermore, the base member 20 in this embodiment has a pair of anchor-shaped engaging pieces 47, 47, but for example, an engaging protrusion may be provided on the outer periphery of the base member, and this engaging protrusion may be engaged with a mounting hole in the member to be mounted; the mounting structure of the base member relative to the mounting hole is not particularly limited.

[0084] Furthermore, in this embodiment, the pair of first guide portions 51, 51 have tapered surfaces that gradually become narrower radially inward of the tubular portion 21, but for example, the first guide portions may be curved surfaces, multiple inclined surfaces, or a combination of curved and inclined surfaces, as long as they are capable of correcting circumferential positional deviation of the elastic piece and guiding the elastic piece to the second guide portion.

[0085] Furthermore, in this embodiment, the pair of second guide portions 53, 53 have flat surfaces parallel to each other, but may also have tapered surfaces that gradually narrow radially inward of the cylindrical portion, and any shape that can guide the elastic piece so as to correct any circumferential positional deviation is sufficient.

[0086] Furthermore, in this embodiment, the cap member 60 has a bottom wall 63 of the lid portion 61 that is approximately circular plate-shaped to correspond to the insertion portion 29 of the approximately cylindrical tubular portion 21 of the base member 20, but the lid portion may also be, for example, an approximately rectangular plate or an approximately oval plate, etc., as long as it is able to cover the outlet of the passage in the base member and receive the gas flowing out from the outlet.

[0087] In this embodiment, the claw portion 71 protrudes from the inner periphery of the tip of the elastic piece 69, but the claw portion may be provided somewhere along the extension direction of the elastic piece, as long as it can engage with the engaged portion. Furthermore, in this embodiment, the claw portion 71 is formed across the entire width of the elastic piece 69, but it may be formed to be narrower or wider than the elastic piece 69.

[0088] Furthermore, although the seal member 80 and the seal washer 8 are both circular, they may be rectangular or elliptical, and may be modified as appropriate depending on the shape and structure of the base member.

[0089] Furthermore, the lid portion 61 of the cap member 60 has the function of receiving the pressure of the gas G, but this lid portion may also have a pressure regulating function that does not allow moisture to pass through but allows a predetermined amount of gas or other vapor to pass through.

[0090] (Action and effect) Next, the effects of the discharge device 10 according to the present invention having the above-described configuration will be described.

[0091] First, the assembly process of the discharge device 10 will be described.

[0092] That is, by inserting the sealing member 80 into the sealing member mounting groove 37 of the base member 20, the sealing member 80 is held in place by the sealing member holding protrusion 39 (see Figure 10), and the sealing member 80 is fitted onto the cylindrical portion 21 of the base member 20.

[0093] Then, as shown in Figure 1, one elastic piece 69 is aligned between one of the guide wall portions 33, 33, and the other elastic piece 69 is aligned between the other guide wall portions 33, 33, and then the cap member 60 is pushed into the base member 20.

[0094] Then, the claw portion 71 is pressed against one of the first guide portions 51, spreading the elastic pieces 69 and bending and deforming them outward from the cap member 60, and the first guide portion 51 corrects the positional deviation of the elastic pieces 69 in the circumferential direction of the tubular portion 21. Thereafter, the elastic pieces 69 enter between the pair of second guide portions 53, 53, and the second guide portions 53 further correct the positional deviation of the elastic pieces 69 in the circumferential direction of the tubular portion 21.

[0095] That is, the two guide portions, the first guide portion 51 and the second guide portion 53, correct the positional deviation of the elastic piece 69 in the circumferential direction of the tubular portion 21, thereby correcting the positional deviation of the claw portion 71 relative to the engaged portion 41. Also, as shown in Fig. 15(a), the top portion 72 of the claw portion 71 is received in the receiving recess 55 provided in the engaged portion 41.

[0096] When the cap member 60 is further pushed into the base member 20, the top 72 of the claw portion 71 comes out of the receiving recess 55, and the top 72 slides against the top 43a of the opposing surface 43 of the engaged portion 41. When the claw portion 71 overcomes the engaged portion 41, the elastic piece 69 elastically returns, and the engaging surface 74 of the claw portion 71 engages with the engaged surface 42 of the engaged portion 41 (see Figure 15(b)).

[0097] As a result, the cap member 60 can be attached to the base member 20 with the seal member 80 interposed between the base member 20 and the cap member 60 via the pair of elastic pieces 69, 69 and their claw portions 71, 71. The seal member 80 is pressed by the pressing portion 67 of the cap member 60, and is crushed within the seal member mounting groove 37 (see FIG. 9).

[0098] Thereafter, seal washer 8 is placed on the back side of flange portion 25 of base member 20, and insertion portion 29 of base member 20 is inserted through the front opening of mounting hole 7a in the workpiece 7. As a result, the pair of engagement pieces 47, 47 are pressed by the inner periphery of mounting hole 7a, causing them to bend inward and deform. When engagement surfaces 47a of engagement pieces 47 come out of the back opening of mounting hole 7a, the pair of engagement pieces 47, 47 elastically return to their original position, and the engagement surfaces 47a, 47a engage with the back periphery of mounting hole 7a, allowing discharge device 10 to be attached to mounting hole 7a (see FIG. 9). In this state, seal washer 8 is sandwiched between flange portion 25 of base member 20 and the front periphery of mounting hole 7a in the workpiece 7, ensuring watertightness.

[0099] When gas G is generated in the energy storage device 1 due to the supply of power from the energy storage device 1 to the drive source or electrical components, or due to the external or internal environment of the energy storage device 1 (for example, when an energy storage device such as a lithium ion battery supplies power by driving a motor or the like, gas is generated by a chemical reaction in the electrolyte), the gas G flows through the connector 3 and gas exhaust tube 4 and reaches the gas exhaust port 6, and when the gas pressure at this gas exhaust port 6 reaches a predetermined value or higher, the cap member 60 comes off from the base member 20.

[0100] That is, the gas G flows into the passage 23 from the inlet 23a of the base member 20, flows through the passage 23, and flows out from the outlet 23b, pressing against the lid portion 61 of the cap member 60, but when the gas pressure at the gas outlet 6 reaches or exceeds a predetermined value, the pressure of the gas G (see FIG. 10) acting on the lid portion 61 of the cap member 60 also reaches or exceeds a predetermined value. Then, the lid portion 61 of the cap member 60 is pressed by the gas G, and the engaging surface 74 of the claw portion 71 is pressed by the curved surface 42b of the engaged surface 42 of the engaged portion 41, and the elastic piece 69 is flexibly deformed outward from the cap member 60 via the claw portion 71.

[0101] As a result, the engagement surface 74 of the claw portion 71 disengages from the horizontal surface 42a and curved surface 42b of the engaged surface 42, and the engagement between the engaged surface 42 and the claw portion 71 is released, so that the cap member 60 can be removed from the base member 20, as shown in Figure 11.

[0102] According to this discharge device 10, the claw portions 71 of the pair of elastic pieces 69, 69 are adapted to engage with the pair of engaged portions 41, 41 in a state where they are bent outward. Therefore, when the cap member 60 is attached to the base member 20, the opposing direction of the pair of elastic pieces 69, 69 is guided by the pair of elastic pieces 69, 69 that are engaged in a state where they are bent outward. In other words, by utilizing the elastic restoring force of the pair of elastic pieces 69, 69, the claw portions 71, 71 can be firmly engaged with the pair of engaged portions 41, 41 in opposing radial directions of the cylindrical portion 21 (for example, it is possible to prevent a situation where only the claw portion 71 of one of the elastic pieces 69 engages with one of the engaged portions 41).

[0103] Furthermore, the elastic piece 69 guided by the first guide portion 51 is further guided by the second guide portion 53, thereby being guided in a direction intersecting the opposing direction of the pair of elastic pieces 69, 69. In other words, when the cap member 60 is attached to the base member 20, the elastic piece 69 guided by the first guide portion 51 is further guided by the second guide portion 53, so that any positional deviation of the elastic piece 69 relative to the engaged portion 41 in the circumferential direction of the tubular portion 21 can be reliably corrected, and the claw portion 71 can be engaged at a predetermined position on the engaged portion 41.

[0104] 12, it is possible to easily align the center C2 of the sealing member 80 with the center C1 of the lid portion 61 of the cap member 60, thereby preventing the pressing portion 67 provided on the lid portion 61 from biting into the sealing member 80 in a biased state, which would cause uneven deformation of the sealing member 80. As a result, it is possible to reliably remove the cap member 60 from the base member 20 when the gas pressure at the gas discharge port 6 reaches or exceeds a predetermined value and the engagement of the claw portion 71 with the engaged portion 41 is released.

[0105] The above-mentioned effects will be explained with reference to FIGS. 14(a) and 14(b).

[0106] As shown in FIG. 14(b), when the pressing portion 67 of the lid portion 61 is engaged with the sealing member 80 while being displaced radially inward (the pressing portion 67, indicated by the two-dot chain line, is displaced in the direction indicated by the arrow in FIG. 14(b)), the deformation of the sealing member 80 becomes uneven. Furthermore, the engagement allowance S1 of the sealing member 80 with the radial outer peripheral edge portion (upper portion in FIG. 14(b)) of the pressing portion 67 of the cap member 60 is large, but the engagement allowance S2 of the sealing member 80 with the radial inner peripheral edge portion (lower portion in FIG. 14(b)) of the pressing portion 67 is small. In this case, the cap member 60 is likely to come off the base member 20 from the portion of the sealing member 80 where the engagement allowance S2 is small. Therefore, when the gas pressure at the gas outlet 6 reaches a predetermined value or higher, the cap member 60 may come off the base member 20.

[0107] In contrast, in the case of the present invention, it is easier to align the center C2 of the sealing member 80 with the center C1 of the lid portion 61 of the cap member 60, and the pressing portion 67 is prevented from biting into the sealing member 80 in a biased state.

[0108] 14(a), the engagement amount S1 of the seal member 80 with the radial outer peripheral edge portion (upper part in FIG. 14(a)) of the pressing portion 67 of the cap member 60 and the engagement amount S2 of the seal member 80 with the radial inner peripheral edge portion (lower part in FIG. 14(a)) of the pressing portion 67 are substantially the same. As a result, it is possible to prevent the seal member 80 from coming off the base member 20 before the gas pressure at the gas discharge port 6 reaches or exceeds a predetermined value, and it is possible to reliably detach the cap member 60 from the base member 20 when the gas pressure at the gas discharge port 6 reaches or exceeds a predetermined value.

[0109] In this embodiment, the pair of first guide portions 51, 51 have tapered surfaces that are inclined so as to gradually narrow inward in the radial direction of the cylindrical portion 21.

[0110] According to the above aspect, even if the elastic piece 69 is misaligned in the circumferential direction of the tubular portion 21 when the cap member 60 is attached to the base member 20, the first guide portion 51 can easily correct the misalignment and can easily guide the elastic piece 69 to the second guide portion 53.

[0111] Furthermore, in this embodiment, a receiving recess 55 is provided on the part of the engaged portion 41 opposite to the mounting direction F1 of the cap member 60 relative to the base member 20, which receives the claw portion 71 of the elastic piece 69 guided by the second guide portion 53.

[0112] According to the above aspect, when the cap member 60 is attached to the base member 20, the claw portions 71 of the elastic pieces 69, guided by the second guide portions 53, are temporarily received in the receiving recesses 55 and positioned axially and circumferentially of the engaged portions 41, and then the claw portions 71 move over the engaged portions 41. Therefore, the pressing force when the cap member 60 is pressed in acts effectively on the claw portions 71, making it easier for the claw portions 71 to move over the engaged portions 41 (without the receiving recesses 55, the claw portions 71 are likely to be misaligned with respect to the engaged portions 41 when the cap member 60 is pressed in, making it difficult for the claw portions 71 to move over the engaged portions 41). As a result, the claw portions 71 can be easily engaged with the engaged surfaces 42 of the engaged portions 41 on the side of the base member 20 in the cap member attachment direction F1, improving the ease of attaching the cap member 60 to the base member 20.

[0113] Also, in this embodiment, as shown in Figure 6, the surface 43 of the engaged portion 41 facing the inner circumference of the elastic piece 69 has a top 43a and a curved surface 43b that gradually becomes lower in the direction away from the top 43a in the circumferential direction of the tubular portion 21.

[0114] According to the above aspect, when the gas pressure at the gas exhaust port 6 reaches or exceeds a predetermined value and the engagement of the claw portion 71 with the engaged portion 41 is released, the claw portion 71 comes into sliding contact only with the apex 43 a of the opposing surface 43 of the engaged portion 41. As a result, sliding resistance when the claw portion 71 moves over the engaged portion 41 can be reduced, making it easier for the claw portion 71 to move over the engaged portion 41 and making it easier to remove the cap member 60 from the base member 20.

[0115] It should be noted that the present invention is not limited to the above-described embodiment, and various modified embodiments are possible within the scope of the gist of the present invention, and such embodiments are also included in the scope of the present invention. [Explanation of symbols]

[0116] 1. Energy storage devices 6 Gas outlet 10 Gas exhaust device for power storage device (exhaust device) 20 Base member 21 Cylindrical part 23 Passage 41 engaged portion 51 First guide section 53 Second guide section 55 Receiving recess 60 Cap member 61 Lid 69 Elastic piece 71 Claw

Claims

1. A gas discharge device for an electricity storage device that discharges gas when a gas pressure at a gas discharge port of the electricity storage device is equal to or greater than a predetermined value, a base member fixed to the gas exhaust port, the base member having a cylindrical portion formed therein with a passage communicating with the gas exhaust port, and an engaged portion provided on the outer periphery of the cylindrical portion; a cap member detachably attached to the base member so as to close an outlet of the passage; a seal member disposed between the base member and the cap member, The cap member has a lid portion, a pressing portion provided on the lid portion for pressing the sealing member, a pair of elastic pieces extending from opposite positions in the circumferential direction of the lid portion, and claw portions formed on each elastic piece for engaging with and disengaging from the engaged portion, and is configured such that when the pair of elastic pieces are flexibly deformed outward, the claw portions engage with the engaged portion, and when the gas pressure at the gas exhaust port is equal to or greater than a predetermined value, the pressure received by the lid portion causes the claw portions to disengage from the engaged portion and the cap member is detached from the base member, the sealing member is fitted to the cylindrical portion while being pressed by the pressing portion, and seals a gap between the base member and the cap member; a pair of first guide portions are provided on the outer periphery of the cylindrical portion, the first guide portions being located on both sides of the elastic piece in the width direction and guiding the elastic piece when the cap member is attached to the base member; and a pair of second guide portions are provided on both sides of the elastic piece in the width direction and positioned radially inward of the cylindrical portion relative to the pair of first guide portions, and further guiding the elastic piece guided by the first guide portions when the cap member is attached; The pair of first guide portions have tapered surfaces that are inclined so as to gradually narrow inward in the radial direction of the cylindrical portion, A gas exhaust device for an electricity storage device, characterized in that when the gap between the pair of first guide portions is L1, the gap between the pair of second guide portions is L2, and the width direction length of the elastic piece is L3, the relationship L1 > L2 > L3 is satisfied.

2. A gas exhaust device for an electrical storage device as described in claim 1, wherein a receiving recess is provided on the part of the engaged portion opposite the attachment direction of the cap member to the base member to receive the claw portion of the elastic piece guided by the second guide portion.

3. The gas discharge device for an electrical storage device as described in claim 1, wherein the surface of the engaged portion facing the inner circumference of the elastic piece has a top and a curved surface that gradually becomes lower in a direction away from the top in the circumferential direction of the cylindrical portion.

Images