Pressure release valve for power storage devices

Abstract

Provided is a pressure relief valve for power storage devices which is easily attached to a case and is difficult to remove from the case. This pressure relief valve 10 for power storage devices has a cylindrical sealing member 20 and a valve unit 15, wherein: the valve unit 15 has a base member provided with a base member-side engagement part 45, a valve body 70, and a coil spring 90; the inner peripheral surface of the sealing member 20 is provided with a temporary engagement part 25 which engages with the base member-side engagement part 45 of the base member at a predetermined insertion position, and a main engagement part 26 which engages with the base member-side engagement part 45 of the base member at an insertion position deeper than the predetermined insertion position; the outer peripheral surface of the sealing member 20 is provided with a retaining part 27; and the retaining part 27 can be bent inward in a temporarily held state and the reduction in the diameter of the retaining part 27 is restricted by the base member in a mainly fixed state.

Description

[Technical Field]

[0001] The present invention relates to a pressure relief valve for an electricity storage device that is attached to a case that houses the electricity storage device and relieves pressure within the case. [Background technology]

[0002] For example, hybrid vehicles and electric vehicles use electricity storage devices such as batteries and capacitors, which are housed in cases installed inside the vehicle. When the electricity storage device is a battery such as a lithium-ion battery, a chemical reaction in the electrolyte can produce gas, causing the pressure inside the case to rise. In this case, a pressure release valve is installed in the case opening to reduce the pressure inside the case.

[0003] For example, Patent Document 1 listed below describes a pressure regulating valve that is installed in a housing to regulate its internal pressure, and that includes a pressure regulating section that regulates the pressure by discharging gas from the housing when the internal pressure is above a certain pressure, and a cover section that contacts the housing and maintains the pressure regulating section in a sealed state.

[0004] The pressure regulating unit has a base portion that is attached to the opening of the housing. This base portion is cylindrical and has multiple flexible legs formed thereon via multiple axially extending slits. Each leg has a locking protrusion protruding from the outer periphery at the tip. When the base portion is inserted into the opening of the housing, the locking protrusions are pressed against the inner periphery of the opening, causing the legs to bend and deform while being inserted. When the locking protrusions come out the back side of the opening, the legs elastically return to their original position, and the locking protrusions lock onto the periphery of the back side of the opening. As a result, the base portion is fixed to the opening, and the entire pressure regulating valve is attached to the opening of the housing. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-21897 Summary of the Invention [Problem to be solved by the invention]

[0006] In the case of the pressure regulating valve of Patent Document 1, as described above, the pressure regulating valve is attached to the opening of the housing using multiple flexible legs provided on the base, and the base is not fixed to the housing with bolts, nuts, etc., so the pressure regulating valve is relatively easy to attach to the opening of the housing. However, the fixing force of the base to the opening of the housing is relatively low, and the base is likely to come off from the opening.

[0007] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a pressure release valve for an electricity storage device that is easy to attach to a case and difficult to come off from the case. [Means for solving the problem]

[0008] In order to achieve the above object, the present invention provides a pressure release valve for an electricity storage device that is attached to a case that houses an electricity storage device, the pressure release valve including: a fixing member that is inserted into and fixed to a case opening formed in the case; and a valve unit that is slidably inserted inside the fixing member, the valve unit including a vent hole that connects an internal space and an external space of the case, a valve seat provided on the periphery of the vent hole, an engaged portion that engages with the fixing member at a predetermined position, a valve body that opens and closes the vent hole, and biasing means that biases the valve body toward the valve seat, The fixing member is provided with a retaining portion that engages with the case, a temporary engagement portion that is provided inside the fixing member and engages with the engaged portion at a predetermined insertion position when the valve unit is inserted into the fixing member, and a final engagement portion that engages with the engaged portion at an insertion position deeper than the temporary engagement portion, and the retaining portion is configured to bend inward in a temporary holding state in which the engaged portion is engaged with the temporary engagement portion, and to have its diameter restricted by the valve unit in a final fixed state in which the engaged portion is engaged with the final engagement portion. [Effects of the Invention]

[0009] According to the present invention, when the fixing member and valve unit are inserted into the case opening in a temporary retaining state in which the engaged portion is engaged with the temporary engaging portion of the fixing member, the retaining portion of the fixing member can bend inwardly of the fixing member, making it easy to insert the valve unit together with the fixing member into the case opening. In this state, when the valve unit is inserted further into the fixing member and the engaged portion engages with the permanent engaging portion of the fixing member, the valve unit is positioned inside the retaining portion of the fixing member, and the retaining portion of the fixing member cannot bend inwardly of the fixing member, restricting its diameter reduction, so that the valve unit can be firmly fixed to the case via the fixing member. As a result, a release valve can be obtained that is easy to attach to the case and does not easily come off from the case. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is an exploded perspective view showing one embodiment of a pressure release valve for an electricity storage device according to the present invention. [Figure 2] FIG. 2 is a perspective view of the pressure release valve for the electricity storage device. [Figure 3] FIG. 2 is an enlarged perspective view of a lower member constituting the pressure release valve for the electricity storage device. [Figure 4] FIG. 2 is an enlarged perspective view of a valve seat forming member that constitutes the pressure release valve for the electricity storage device. [Figure 5A] 3 is an enlarged perspective view showing an upper member that constitutes the pressure release valve for the electricity storage device. FIG. [Figure 5B] 3 is a bottom view of the upper member that constitutes the pressure release valve for the electricity storage device. FIG. [Figure 6] FIG. 2 is an enlarged perspective view of a valve body that constitutes the pressure release valve for the electricity storage device. [Figure 7] FIG. 2 is an enlarged perspective view of a cap that constitutes the pressure release valve for the electricity storage device. [Figure 8] FIG. [Figure 9] FIG. 2 is an enlarged perspective view of a sealing member that constitutes the pressure release valve for the electricity storage device. [Figure 10] FIG. 2 is an enlarged perspective view of a cover member that constitutes the pressure release valve for the electricity storage device. [Figure 11] 4 is an explanatory cross-sectional view showing a first assembly step of the pressure release valve for the electricity storage device. FIG. [Figure 12] 10 is a cross-sectional view illustrating a second assembly step of the pressure release valve for the electricity storage device. FIG. [Figure 13] 10A to 10C are cross-sectional explanatory views showing a first step of attaching the pressure release valve for an electricity storage device to a case. [Figure 14] 10 is a cross-sectional view illustrating a second step in the process of attaching the pressure release valve for the electricity storage device to the case. FIG. [Figure 15] 10 is a cross-sectional view illustrating the third step of attaching the pressure release valve for the electricity storage device to the case. FIG. [Figure 16] 16 is an explanatory cross-sectional view showing a state in which the valve disc separates from the valve seat and the vent hole opens from the state shown in FIG. 15. FIG. [Figure 17] FIG. 10 is an exploded perspective view showing another embodiment of a pressure release valve for an electricity storage device according to the present invention. [Figure 18] FIG. 2 is a perspective view of the pressure release valve for the electricity storage device. [Figure 19] FIG. 2 is an enlarged perspective view of a base member that constitutes the pressure release valve for the electricity storage device. [Figure 20] FIG. 2 is an enlarged perspective view of a cover member that constitutes the pressure release valve for the electricity storage device. [Figure 21] 3 is an enlarged perspective view of a pushing member that constitutes the pressure release valve for the electricity storage device. FIG. [Figure 22] FIG. 2 is an enlarged perspective view of a cap member that constitutes the pressure release valve for the electricity storage device. [Figure 23] 4 is an explanatory cross-sectional view showing a first assembly step of the pressure release valve for the electricity storage device. FIG. [Figure 24] 10 is a cross-sectional view illustrating a second assembly step of the pressure release valve for the electricity storage device. FIG. [Figure 25] 10 is a cross-sectional view illustrating a third assembly step of the pressure release valve for the electricity storage device. FIG. [Figure 26] 10A to 10C are cross-sectional explanatory views showing a process of attaching the pressure release valve for the electricity storage device to the case. [Figure 27] 19 is a cross-sectional explanatory view taken along the line AA in FIG. 18, showing the pressure release valve for an electricity storage device attached to the case. [Figure 28] 19 is an enlarged cross-sectional explanatory view taken along the line BB in FIG. 18, showing the pressure release valve for an electricity storage device attached to the case. [Figure 29] 19 is an enlarged cross-sectional explanatory view taken along the line DD in FIG. 18, showing the pressure release valve for an electricity storage device attached to the case. FIG. [Figure 30] 28 is an explanatory cross-sectional view showing a state in which the valve disc separates from the valve seat and the vent hole opens from the state shown in FIG. 27. FIG. [Figure 31] 19 is a perspective view showing a state in which a plate-like piece provided on a cover member is opened from the state shown in FIG. 18. FIG. [Figure 32] FIG. 10 is a perspective view showing still another embodiment of a pressure release valve for an electricity storage device according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] (One embodiment of a pressure release valve for an electricity storage device) Hereinafter, one embodiment of a pressure release valve for an electricity storage device according to the present invention will be described with reference to the drawings.

[0012] As shown in Figures 15 and 16, this pressure release valve 10 for an electricity storage device (hereinafter simply referred to as "release valve 10") is attached to a case 1 that houses an electricity storage device (not shown), and is used to release (reduce) the pressure inside the case when the pressure increases.

[0013] Examples of the electricity storage device 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.

[0014] As shown in FIG. 1, the case 1 has a case opening 3. More specifically, the case 1 in this embodiment has a recess 2 formed therein that is substantially circular. A recess that is substantially circular and deeper than the recess 2 is provided at the bottom of the recess 2, with a circular hole formed in the center of the recess and a cylindrical portion 3a protruding from the rear periphery of the circular hole. The cylindrical portion 3a and the inner periphery of the circular hole form the case opening 3. The bottom of the recess, which is deeper than the recess 2, forms the front periphery 4 of the case opening 3. As shown in FIGS. 13 to 16, the internal space of the case 1 forms a case internal space R1, and the external space of the case 1 forms a case external space R2.

[0015] 1 and 13, the release valve 10 in this embodiment has a fixing member that is inserted into and fixed in the case opening 3, and a valve unit 15 that is slidably inserted inside the fixing member. The fixing member in this embodiment is a cylindrical sealing member 20. The valve unit 15 is inserted inside the sealing member 20 and is fixed to the case 1 via the sealing member 20.

[0016] The valve unit 15 also has a vent hole 52 that connects the case internal space R1 and the case external space R2, a valve seat 53 provided on the periphery thereof, an engaged portion that engages with the fixed member at a predetermined position, a valve body 70 that opens and closes the vent hole 52, and a biasing means that biases the valve body 70 toward the valve seat 53.

[0017] Furthermore, in this embodiment, the "engaged portion" in the present invention refers to a base member side engaging portion 45 and a pressing portion 41a, which will be described later, as shown in Figure 14. These engage with a temporary engaging portion 25, which will be described later, and the inner circumferential surface of the main body portion 21, respectively, thereby holding the valve unit 15 in a temporary holding state relative to the fixing member. Furthermore, the base member side engaging portion 45 and the pressing portion 41a engage with a final engaging portion 26 and a pressing protrusion 28, which will be described later, respectively, thereby holding the valve unit 15 in a final fixed state relative to the fixing member.

[0018] In this embodiment, the temporary engagement portion 25 and the inner peripheral surface of the main body portion 21 form a "temporary engagement portion" to be described later in this invention. The full engagement portion 26 and the pressing protrusion 28 form a "full engagement portion" to be described later in this invention.

[0019] Furthermore, the valve unit 15 in this embodiment has a base member having an engaged portion, and the valve element 70 is slidable relative to the base member. The base member is also provided with a base member-side engaging portion 45 that engages with the seal member 20.

[0020] Furthermore, as shown in Figure 11, in this embodiment, a first assembly 15A is formed by assembling four parts: an upper member 60, a valve body 70, a cap 80, and a coil spring 90. Also as shown in Figure 11, a second assembly 15B is formed by assembling two parts: a lower member 40 and a valve seat forming member 50. Note that the biasing means in this embodiment is a coil spring 90 formed by winding a wire rod of a predetermined diameter at a predetermined interval.

[0021] As shown in FIG. 12, a cover member 30 is attached to the seal member 20.

[0022] In this embodiment, the "base member" in the present invention is composed of a lower member 40, a valve seat forming member 50 attached to the lower member 40 and provided with a valve seat 53, and an upper member 60 assembled to the lower member 40. A cap 80 is attached to the valve body 70 and is integrated with the valve body 70.

[0023] In the following description, the terms "front side" and "surface side" refer to the side facing the case 1, and the terms "rear side" and "rear side" refer to the side opposite to the "front side" and "surface side." This also applies to other components (such as a base member, a seal member, a valve member, and a cap) described below. In the following description, the insertion direction F of the release valve 10 into the case opening 3 (the insertion direction of the release valve 10 into the case opening 3) as shown in FIG. 13 will also be simply referred to as the "insertion direction F." In addition, the insertion direction of the first assembly 15A into the second assembly 15B (the insertion direction of the first assembly 15A into the second assembly 15B) as shown in FIG. 11 and the insertion direction of the valve unit 15 into the seal member 20 (the insertion direction of the valve unit 15 into the seal member 20) as shown in FIG. 12 will also be referred to as the "insertion direction F."

[0024] First, the lower member 40 constituting the base member will be described with reference to Figs. 3 and 11 and the like.

[0025] The lower member 40 has a tubular portion 41 having a substantially cylindrical shape. A pressing portion 41a having a rounded arc shape is provided on the outer periphery of the axial base end (the end on the insertion direction F side) of the tubular portion 41. An annular flange portion 42 extends from the outer periphery of the axial tip end (the end opposite to the insertion direction F) of the tubular portion 41. Furthermore, a plurality of (four in this example) engagement pieces 43 having engagement holes 43a are erected at equal intervals from the axial tip surface of the tubular portion 41. A guide groove 43b is formed on the inner surface of the erected tip of each engagement piece 43. When inserting the engagement pieces 62 of the upper member 60 into the tubular portion 41 of the lower member 40 to assemble the lower member 40 and the upper member 60, the guide groove 43b guides the engagement claws 63 (see FIG. 5 ) protruding from the outer surface of the engagement piece 62, making it easier to engage with the engagement holes 43a.

[0026] Furthermore, an annular protrusion 44 protrudes inward from the inner periphery of the cylindrical portion 41 on the axial base end side. A base member side engaging portion 45 also protrudes from the outer periphery of the cylindrical portion 41 at a predetermined axial position (here, a position slightly closer to the axial base end side). A tapered surface 45a is formed on the outer surface of the base end of the base member side engaging portion 45.

[0027] Next, the valve seat forming member 50 attached to the lower member 40 will be described with reference to FIGS.

[0028] The valve seat forming member 50 is formed from an elastic material such as rubber or an elastic elastomer, and has a tubular portion 51 having a substantially cylindrical shape. The internal space of the tubular portion 51 forms a vent hole 52. As shown in FIG. 16 , the internal space R1 of the case 1 and the external space R2 of the case 1 communicate with each other via the vent hole 52. A valve seat 53 is provided on the axial tip surface (the end surface opposite to the insertion direction F) of the tubular portion 51, on the outer periphery of the vent hole 52. Furthermore, a tapered surface 51a is formed on the outer periphery of the axial base end portion (the end portion on the insertion direction F side) of the tubular portion 51.

[0029] 11 , the cylindrical portion 51 is disposed on the inner periphery of the base end of the lower member 40, and the annular protrusion 44 of the lower member 40 is engaged with the cylindrical portion 51. As shown in FIG. 11 , the cylindrical portion 51 is disposed on the inner periphery of the base end of the lower member 40, and the annular protrusion 44 of the lower member 40 is engaged with the cylindrical portion 51, thereby attaching the valve seat forming member 50 to the lower member 40. As a result, the vent hole 52 and the valve seat 53 are provided in the lower member 40.

[0030] Next, the upper member 60 to be assembled to the lower member 40 will be described with reference to FIGS.

[0031] The upper member 60 has an annular base 61 having a generally circular ring shape. A plurality of engagement pieces 62 are vertically extended at equal intervals from a base end surface (the end surface on the insertion direction F side) of the annular base 61. Here, four engagement pieces 62 are provided corresponding to the engagement pieces 43 of the lower member 40. Note that, when the upper member 60 is assembled to the lower member 40, each engagement piece 62 is disposed inside the corresponding engagement piece 43 of the lower member 40. Furthermore, each engagement piece 62 is formed with an engagement claw 63 that is flexible and deformable via a generally U-shaped slit 63a.

[0032] As shown in Figure 12, an engagement piece 62 is arranged inside the engagement piece 43 of the lower member 40, and its engagement claw 63 engages with the inner circumference of the engagement hole 43a of the engagement piece 43 of the lower member 40, thereby assembling the upper member 60 to the lower member 40.

[0033] Furthermore, an annular ceiling portion 64 is disposed at the radial center of the annular base portion 61, at a position protruding beyond the annular base portion 61. Furthermore, the annular base portion 61 and the ceiling portion 64 are connected to each other by a plurality of ribs 65 that extend radially from the axis of the upper member 60. Furthermore, openings 66 are formed between adjacent ribs 65, 65, which connect the internal space and external space of the base member. Furthermore, a substantially cylindrical tube portion 67 hangs down from the rear peripheral edge of the ceiling portion 64.

[0034] Next, the valve body 70 slidably housed within the base member will be described with reference to FIGS. 6 and 11. FIG.

[0035] The valve body 70 has a flange portion 72 that contacts and separates from the valve seat 53, and a shaft portion 71 that protrudes from the radial center of the front side of the flange portion 72. The shaft portion 71 is generally cylindrical, with a closed ceiling surface 71a at its axial tip end (the end opposite the insertion direction F). It can also be said that the flange portion 72 has a shape that expands into an annular shape from the outer periphery of the axial base end (the end on the insertion direction F side) of the shaft portion 71. As shown in FIG. 11 , the shaft portion 71 is disposed coaxially with the tubular portion 67 of the upper member 60, and is slidably inserted and supported within the tubular portion 67.

[0036] Furthermore, the flange portion 72 of the valve body 70 is disposed opposite the ceiling portion 64 and ribs 65 of the upper member 60. The flange portion 72 has a circular outer periphery, and its outer diameter is larger than the inner diameter of the tubular portion 51 of the valve seat forming member 50, so that it moves toward and away from the valve seat 53 to open and close the vent port 52. Furthermore, the outer diameter of the flange portion 72 is formed to have dimensions that approximately fit the inner diameters of the multiple engagement pieces 62 of the upper member 60 (see FIG. 13), so that the valve body 70 can slide up and down within the upper member 60 while being prevented from tilting.

[0037] An annular recess 72a recessed to a predetermined depth is formed in the inner diameter portion on the front side of the flange portion 72, and one end (the axial base end) of the coil spring 90 abuts against and is supported by the bottom surface of the annular recess 72a. Furthermore, an annular protruding seal protrusion 73 protrudes from the outer circumferential edge portion on the back side of the flange portion 72. This seal protrusion 73 moves toward and away from the valve seat 53 of the valve seat forming member 50 to open and close the vent port 52 (see FIGS. 15 and 16).

[0038] In relation to the valve element 70, the relationship with the coil spring 90, which is the biasing means, will be described. As shown in Figure 11, this coil spring 90 is disposed on the outer periphery of the tubular portion 67 of the upper member 60, into which the shaft portion 71 of the valve element 70 is inserted, with one end thereof abutting and supported on the bottom surface of the annular recess 72a of the flange portion 72 of the valve element 70, and the other end (the axial tip) abutting and supported on the back side peripheral edge of the tubular portion 67 of the ceiling portion 64 of the upper member 60. As a result, the coil spring 90 is housed and held in a compressed state within the base member, and biases the valve element 70 toward the valve seat 53.

[0039] Returning to the explanation of the valve body 70, a protrusion 75 protrudes from the radial center of the ceiling surface 71a of the shaft portion 71, and a strip-shaped retaining piece 75a is attached to the tip of the protrusion 75. As shown in Figure 11, the protrusion 75 and the retaining piece 75a are inserted into the shaft insertion hole 84a of the cap 80, and the retaining piece 75a engages with the peripheral edge of the front side of the shaft insertion hole 84a when the valve body 70 is rotated by a predetermined angle.

[0040] Next, the cap 80, which is fixed to and integrated with the valve body 70, will be described with reference to Figures 7, 8, 11, etc.

[0041] The cap 80 of this embodiment has a ceiling portion 81 having a substantially circular plate shape, a peripheral wall 83 extending obliquely outward from the outer periphery of the ceiling portion 81, and a seal flange portion 85 extending annularly from the outer periphery of a base end (the end on the insertion direction F side) of the peripheral wall 83. As shown in Fig. 15, the cap 80 has a shape with a larger diameter than the outer periphery of the lower member 40 and the upper member 60 so as to be able to cover the entire base member. The seal flange portion 85 can be brought into contact with and separated from the flange portion 32 of the cover member 30 constituting the seal member 20, thereby opening and closing the multiple openings 66 formed in the lower member 40 (see Figs. 15 and 16).

[0042] A circular recess 84 having a predetermined depth is formed in the radial center of the front side of the ceiling 81. A keyhole-shaped shaft insertion hole 84a is formed in the bottom of the recess 84. As shown in Fig. 8, a pair of retaining projections 84b, 84b are provided at the bottom of the recess 84, on the outer periphery of the shaft insertion hole 84a.

[0043] Then, after the protrusion 75 and the retaining piece 75a of the valve body 70 are inserted into the shaft insertion hole 84a, the cap 80 is rotated 90° and the retaining piece 75a is engaged with the front peripheral edge of the shaft insertion hole 84a, thereby preventing the cap 80 from coming off from the valve body 70 and integrating the valve body 70 and the cap 80. In this state, one end of the retaining piece 75a fits between the pair of retaining protrusions 84b, 84b, preventing the cap 80 from rotating relative to the valve body 70.

[0044] As a result of the cap 80 being integrated with the valve body 70 in this manner, as the valve body 70 slides relative to the base member, the cap 80 also moves toward or away from the front side of the upper member 60 that constitutes the base member, and its seal flange portion 85 moves toward or away from the flange portion 32 of the cover member 30.

[0045] Next, the sealing member 20 will be described with reference to FIGS.

[0046] The seal member 20 is formed from an elastic material such as rubber or an elastic elastomer, and has a substantially cylindrical main body 21. The tubular portion 41 of the lower member 40 is inserted into the main body 21.

[0047] A pair of annular protrusions 22, 23 having an annular projection shape are provided in parallel on the outer periphery of the main body 21 at the axial tip end (the end opposite to the insertion direction F). The annular protrusion 22 protrudes from the outer periphery of the axial tip end of the main body 21, and the annular protrusion 23 is positioned closer to the axial base end (the end on the insertion direction F side) of the main body 21 than the annular protrusion 22 and has a larger diameter than the annular protrusion 22. As shown in FIG. 14 , the annular protrusion 23 is a portion that abuts against the front peripheral edge 4 of the case opening 3 of the case 1.

[0048] Furthermore, an annular groove-shaped mounting groove 24 is formed on the outer periphery of the main body 21, between the annular protrusions 22, 23. The cover member 30 is mounted on the seal member 20 via this mounting groove 24.

[0049] In relation to the mounting groove 24, the cover member 30 will be described with reference to FIGS.

[0050] The cover member 30 comprises a generally cylindrical tubular portion 31, a thin-walled annular flange portion 32 that widens from the axial tip end (the end opposite to the insertion direction F) of the tubular portion 31, and a mounting projection 33 that forms an annular protrusion that protrudes from the inner periphery of the axial base end (the end on the insertion direction F side) of the tubular portion 31 and is inserted into the mounting groove 24 of the seal member 20. The axial tip end of the main body 21 of the seal member 20 can be inserted into the tubular portion 31. The flange portion 32 is arranged to face the front peripheral edge 4 of the case opening 3 with a predetermined gap therebetween when the release valve 10 is fixed to the case opening 3 (see FIG. 14).

[0051] 12, by inserting the mounting protrusion 33 of the cover member 30 into the mounting groove 24 of the seal member 20, the mounting protrusion 33 is sandwiched between the pair of annular protrusions 22, 23, and the cover member 30 is attached to the seal member 20. As a result, the outer periphery of the axial tip end side of the seal member 20 is covered by the cover member 30. Note that the seal flange portion 85 of the cap 80 described above comes into contact with and separates from the surface side of the flange portion 32 (see FIGS. 15 and 16), opening and closing the opening 31a on the axial tip end side of the cover member 30.

[0052] The seal member 20 will now be described.

[0053] On the inside of the fixed member, which is a sealing member, there is provided a temporary engagement portion that engages with the engaged portion at a predetermined insertion position when the valve unit 15 is inserted into the fixed member, and a full engagement portion that engages with the engaged portion at an insertion position deeper than the temporary engagement portion.

[0054] In this embodiment, the inner circumference of the seal member 20 is provided with a temporary engagement portion 25 that engages with the base member side engagement portion 45 of the base member at a predetermined insertion position when the valve unit 15 is inserted into the seal member 20, and a full engagement portion 26 that engages with the base member side engagement portion 45 of the base member at an insertion position deeper than the temporary engagement portion 25.

[0055] 12 and 14, a hollowed portion 21a is formed by hollowing out the inner periphery of the main body 21 of the seal member 20 on the axial tip side of the inner periphery of the main body 21. A temporary engagement portion 25 having an annular projection projects radially inward from the axial tip of the inner periphery of the main body 21 via the hollowed portion 21a.

[0056] 13 and 14, the base member-side engaging portion 45 on the base member side engages with the rear peripheral edge of this temporary engaging portion 25, thereby temporarily holding the valve unit 15 to the seal member 20. This temporary engaging portion 25 is disposed at the same axial height as the annular protrusion 22. That is, the annular protrusion 22 and the temporary engaging portion 25 are provided on the outer periphery and inner periphery, respectively, of the axial tip of the main body 21.

[0057] Also, as shown in Figure 14, the recessed portion 21a makes it possible to ensure a clearance between the tapered surface 45a of the base member side engaging portion 45 and the inner periphery of the main body portion 21 when the base member side engaging portion 45 is engaged with the temporary engaging portion 25, making it easier to push the valve unit 15 into the main body portion 21 of the sealing member 20.

[0058] Furthermore, a tapered surface 25a is formed on the inner periphery of the main body portion 21, from a position closer to the axial base end than the temporary engagement portion 25, such that the amount of protrusion inward of the main body portion 21 gradually increases toward the axial base end of the main body portion 21.

[0059] Furthermore, a main engagement portion 26 in the form of an annular groove of a predetermined depth is formed on the inner periphery of the main body portion 21 at an axially intermediate position, here adjacent to the apex of the tapered surface 25a (the portion that protrudes most inwardly into the main body portion). As shown in Figure 15, a base member-side engagement portion 45 on the base member side is inserted into this main engagement portion 26, and this base member-side engagement portion 45 engages with the inner circumferential surface of the axial tip side of the main engagement portion 26, thereby finally fixing the valve unit 15 to the seal member 20.

[0060] Furthermore, the seal member 20 is provided with a retaining portion 27 that engages with the case 1. In addition, in a main fixed state in which the main engaging portion 26 of the seal member 20 is engaged with the base member side engaging portion 45 of the base member, the outer peripheral surface of the seal member 20 is adapted to engage with the case 1 (in this embodiment, as shown in FIG. 15 , an engaging protrusion 29 provided on the outer peripheral surface of the base end of the retaining portion 27 engages with the rear peripheral edge of the case opening 3).

[0061] The anti-slip portion 27 provided on the fixed member, which is a sealing member, is configured to be able to bend inward in a temporary holding state in which the engaged portion is engaged with the temporary engaging portion, and to be able to restrict diameter reduction by the valve unit 15 in a final fixed state in which the engaged portion is engaged with the final engaging portion.

[0062] In this embodiment, this anti-slip portion 27 is able to bend inward in a temporary holding state in which the temporary engagement portion 25 of the sealing member 20 is engaged with the base member side engagement portion 45 of the base member (see Figure 14), and in a permanently fixed state in which the base member side engagement portion 45 of the base member is engaged with the permanent engagement portion 26 of the sealing member 20, the base member is positioned inside the anti-slip portion 27, so that the base member restricts the reduction in diameter of the anti-slip portion 27 and it is configured to engage with the rear peripheral edge of the case opening 3 (see Figure 15).

[0063] More specifically, the anti-slip portion 27 is provided in a flexible and deformable manner at a position on the main body 21 of the sealing member 20 closer to the axial base end than the main engagement portion 26 (a position closer to the insertion direction F relative to the case opening 3 than the main engagement portion 26).

[0064] Furthermore, a pressing protrusion 28 having an annular projection-like shape is provided on the inner peripheral surface of the retaining portion 27, protruding from the axially most proximal end. This pressing protrusion 28 constitutes the "protrusion" of the present invention. As shown in FIG. 14 , the inner diameter of this pressing protrusion 28 is smaller than the outer diameter of the tubular portion 41 of the lower member 40. Therefore, when the valve unit 15 is further pressed into the seal member 20 from the temporarily held state in which the valve unit 15 is temporarily held in the seal member 20 as shown in FIG. 14 , the pressing protrusion 28 is pressed by the pressing portion 41 a on the outer periphery of the base end of the tubular portion 41 of the lower member 40, causing the retaining portion 27 to bend and deform outward from the seal member 20.

[0065] Furthermore, a tapered surface 28a is formed on the outer surface of the pressing protrusion 28, gradually increasing the amount of protrusion toward the insertion direction F. By forming this tapered surface 28a, when the pressing protrusion 28 is pressed by the cylindrical portion 41 of the lower member 40, the pressing protrusion 28 is more easily pressed.

[0066] An annular engagement protrusion 29 protrudes from the outer peripheral surface of the retaining portion 27 at the axially most proximal end. That is, the retaining portion 27 in this embodiment has a pressing protrusion 28 and an engagement protrusion 29 protruding from the inner and outer peripheral surfaces of its axially most proximal end (the most extreme end in the insertion direction F with respect to the case opening 3). As shown in FIG. 15 , the engagement protrusion 29 engages with the rear peripheral edge of the case opening 3 (the rear end surface of the tubular portion 3 a) when the retaining portion 27 is pressed by the pressing protrusion 28 and is bent and deformed outwardly by the seal member 20. Furthermore, the engagement protrusion 29 and the annular protrusion 23 sandwich the case opening 3 (here, the portion from the front side of the case opening 3 to the proximal end of the tubular portion 3 a) of the case 1.

[0067] The outer surface of the engaging protrusion 29 is formed with a tapered surface 29a that gradually reduces the amount of protrusion toward the insertion direction F. This tapered surface 29a makes it easier to insert the main body 21 of the seal member 20 into the case opening 3. As shown in FIG. 13, the outer diameter of the engaging protrusion 29 (the outer diameter of the most protruding top portion) is larger than the inner diameter of the case opening 3 of the case 1. Therefore, as shown by arrow F in FIG. 13, when the valve unit 15 is inserted into the case opening 3, the top portion of the engaging protrusion 29 and the tapered surface 29a are pressed against the inner periphery of the case opening 3, causing the retaining portion 27 to bend and deform inwardly of the seal member 20.

[0068] In this seal member 20, the valve unit 15 is temporarily held or fully fixed as follows.

[0069] 12, when the valve unit 15 is pushed in the insertion direction F relative to the seal member 20, the cylindrical portion 41 of the lower member 40 is inserted into the main body 21 of the seal member 20. Then, the tapered surface 45a of the base member side engaging portion 45 of the lower member 40 is pressed against the temporary engaging portion 25 of the seal member 20, and the cylindrical portion 41 of the lower member 40 is deformed slightly inward.

[0070] 13 and 14, when base member side engaging portion 45 moves over temporary engaging portion 25, base member side engaging portion 45 engages with the rear peripheral edge of temporary engaging portion 25, and pressing portion 41a engages with the inner periphery of main body portion 21, so that valve unit 15 is temporarily held at a relatively shallow insertion position relative to seal member 20. In this temporarily held state, tubular portion 41 of lower member 40 is not positioned inside retaining portion 27, so retaining portion 27 is able to flex and deform inward of seal member 20.

[0071] In addition, it can also be said that the anti-slip portion 27 of the sealing member 20 extends further toward the insertion direction F than the base end of the tubular portion 41 of the lower member 40 when in a temporary holding state in which the temporary engagement portion 25 is engaged with the base member side engagement portion 45.

[0072] When the valve unit 15 is further pushed in the insertion direction F toward the sealing member 20 from the above-mentioned temporary holding state, the base member side engaging portion 45 disengages from the temporary engaging portion 25 and moves a predetermined distance within the recessed portion 21a, after which the base member side engaging portion 45 slides on the tapered surface 25a within the main body portion 21, and when the base member side engaging portion 45 is inserted into the main engaging portion 26, the base member side engaging portion 45 engages with the inner surface at the axial tip side of the main engaging portion 26, and as will be described later, the pressing portion 41a engages with the pressing protrusion 28, and the valve unit 15 is finally fixed to the sealing member 20 at an insertion position deeper than the above-mentioned temporary holding state (see Figure 15).

[0073] At the same time, tapered surface 28a of pressing protrusion 28 of retaining portion 27 is pressed by pressing portion 41a of tubular portion 41 of lower member 40, causing retaining portion 27 to bend and deform outward from seal member 20, and engaging protrusion 29 on the outer periphery of the base end of retaining portion 27 engages with the rear peripheral edge of case opening 3 (the rear peripheral edge of tubular portion 3a of case opening 3). In other words, it can be said that pressing portion 41a engages with pressing protrusion 28. As a result, valve unit 15 is fixed to case opening 3 via seal member 20. In the above-described fixed state, tubular portion 41 of lower member 40 is disposed inside retaining portion 27, so that inward bending and deformation of seal member 20 are suppressed, and the diameter reduction of retaining portion 27 is restricted.

[0074] (Variation) In the embodiment described above, the case 1 is configured with the case opening 3 at the bottom of a plurality of recesses, but it may also be configured without recesses and with the case opening provided directly in a wall such as the ceiling wall of the case 1. The case opening may also be rectangular, square, elliptical, or other shape as long as it is a shape that allows the release valve to be attached.

[0075] Furthermore, the shapes and structures of the seal member, cover member, lower member, valve seat forming member, upper member, valve body, cap, etc. that constitute the pressure release valve are not limited to the above embodiments.

[0076] For example, the main body of the seal member, the tubular portion of the cover member, the tubular portion of the lower member, the tubular portion of the valve seat forming member, etc. are cylindrical, but these portions may be elliptical or rectangular, etc. Furthermore, the flange portion of the valve disc has a circular outer periphery corresponding to the shapes of the tubular portions of the valve seat forming member and upper member, but it may also be elliptical or rectangular, for example, as long as it is shaped so as to be able to come into contact with and separate from the valve seat of the valve seat forming member to open and close the vent hole.

[0077] Furthermore, in this embodiment, the seal member 20 and the cover member 30, and the lower member 40 and the valve seat forming member 50 are each separate bodies, but the seal member and the cover member, and the lower member and the valve seat forming member may each be integrally formed by so-called two-shot molding, in which, for example, the cover member and the lower member are molded in a specified mold and then the seal member and the valve seat forming member are molded in the same mold while they are still held in place.

[0078] Furthermore, in this embodiment, the structure for engaging the upper member and the lower member is such that an engaging piece 43 with an engaging hole 43a is provided on the lower member 40 side, and an engaging claw 63 that engages with the engaging hole 43a is provided on the upper member 60 side. However, for example, an engaging claw or an engaging leg may be provided on the lower member side, and an engaging hole that engages them may be provided on the upper member side; the engaging structure between the upper member and the lower member is not particularly limited.

[0079] Furthermore, in this embodiment, the cylindrical portion 67 is provided on the upper member 60 side, and the shaft portion 71 is provided on the flange portion 72 side of the valve body 70 (see Figure 11), but the opposite may also be true: the cylindrical portion may be provided on the flange portion side of the valve body, and the shaft portion that is inserted into the cylindrical portion and supported by sliding may be provided on the upper member side.

[0080] Furthermore, although the retaining portion 27 of the seal member 20 in this embodiment has a continuous cylindrical wall shape, the retaining portion may have, for example, (1) a structure consisting of multiple flexible pieces that are separated and arranged circumferentially of the seal member by multiple axially extending slits, (2) a shape in which the continuous cylindrical wall or multiple flexible pieces described above gradually narrows while describing a curved or tapered surface toward the axial base end of the seal member, or (3) a bulged portion may be provided midway in the axial direction of the continuous cylindrical wall or multiple flexible pieces. In other words, the retaining portion may have a structure that can engage with the case (a structure that can engage with the back peripheral edge of the case opening) when the main engaging portion is engaged with the base member side engaging portion in the final fixed state, and the base member is positioned inside the retaining portion in the final fixed state so that the base member can regulate the diameter reduction of the retaining portion.

[0081] Furthermore, in this embodiment, pressing protrusions 28 and engaging protrusions 29 are provided on the inner and outer peripheral surfaces of retaining portion 27, but one or both of these protrusions may be absent. If pressing protrusions 28 are not provided on the inner peripheral surface of retaining portion 27, it is preferable to have a structure in which the inner peripheral surface of the retaining portion can be expanded from the inside by the outer peripheral surface of the valve unit when the main fixing state is achieved in which the base member side engaging portion engages with the main engaging portion (for example, the dimension of the inner peripheral base end of the retaining portion is made smaller than the dimension of the outer peripheral base end of the valve unit).

[0082] On the other hand, even if an engaging protrusion 29 is not provided on the outer peripheral surface of the anti-slip portion 27, it is sufficient that the anti-slip portion can engage with the case when the base member side engaging portion engages with this engaging portion to achieve the final fixed state (for example, if a pressing protrusion 28 is provided on the inner peripheral surface of the anti-slip portion 27, the anti-slip portion 27 will be pushed open from the inside when the valve unit or seal member is finally fixed, and its outer peripheral surface will be able to engage with the back peripheral edge of the case opening 3).

[0083] Furthermore, the base member in this embodiment is a case-shaped valve case that accommodates the valve body in a slidable manner within the internal space of the lower member and the upper member, but the base member may have any shape or structure as long as it has an air vent and a valve seat, is provided with an engaging portion on its outer periphery, and is capable of supporting the valve body in a slidable manner.

[0084] Furthermore, although the upper member 60 of this embodiment has a plurality of openings 66 that are opened and closed by caps 80, the upper member may be configured without openings, without providing caps. In this case, however, it is preferable to form slots or the like in the peripheral wall of the base member that can communicate with the vent holes, allowing gas to circulate within the case. In other words, any shape or structure may be used that allows communication between the internal and external spaces of the case when the valve disc separates from the valve seat and opens the vent holes.

[0085] Furthermore, in this embodiment, the base member side engaging portion 45 and pressing portion 41a, which form the "engaged portion," engage with the temporary engaging portion 25, which form the "temporary engaging portion," and the inner surface of the main body portion 21, respectively, thereby holding the valve unit 15 in a temporary holding state relative to the fixed member, and by engaging with the main engaging portion 26 and pressing protrusion 28, which form the "main engaging portion," respectively, the valve unit 15 is held in a main fixed state relative to the fixed member.

[0086] That is, the base member side engaging portion 45 and the pressing portion 41a which constitute the "engaged portion" in this embodiment are used for both engagement with the temporary engaging portion and engagement with the main engaging portion, and serve both as temporary engagement and main engagement, but the "engaged portion" may have different shapes or structures or be provided at different positions for engagement with the temporary engaging portion and for engagement with the main engaging portion (it may also have separate and independent shapes, structures or layouts that are not a combined structure).

[0087] (Action and effect) Next, the effects of the release valve 10 according to the present invention having the above-described structure will be described.

[0088] First, the assembly process of the release valve 10 will be described.

[0089] 11, the axial tip of the coil spring 90 is placed on the outer periphery of the tubular portion 67 of the upper member 60, and the axial tip of the coil spring 90 is supported in contact with the rear peripheral edge of the ceiling portion 64. At the same time, the shaft portion 71 of the valve body 70 is inserted from the rear opening of the tubular portion 67 of the upper member 60, and the axial base end of the coil spring 90 is supported in contact with the bottom surface of the annular recess 72a of the valve body 70. In this state, the cap 80 is placed on the front side of the upper member 60, and the protrusion 75 and retaining piece 75a of the valve body 70 are aligned with the shaft insertion hole 84a (see FIG. 8), and then the protrusion 75 and retaining piece 75a are inserted and removed from the shaft insertion hole 84a.

[0090] Thereafter, the cap 80 is rotated 90° to lock the retaining piece 75a onto the peripheral edge of the front side of the shaft insertion hole 84a, and one end of the retaining piece 75a is fitted between the pair of retaining projections 84b, 84b (see FIG. 8), thereby attaching the cap 80 to the valve body 70 in a state in which the cap 80 is prevented from coming off and its rotation is restricted relative to the valve body 70. As a result, the first assembly 15A is assembled, which is made up of four parts: the upper member 60, the valve body 70, the cap 80, and the coil spring 90.

[0091] In the above state, the coil spring 90 is compressed and interposed between the upper member 60 and the valve body 70, so that the flange portion 72 of the valve body 70 is biased in a direction away from the ceiling portion 64 of the upper member 60.

[0092] 11, the valve seat forming member 50 can be attached to the lower member 40 by inserting the cylindrical portion 51 of the valve seat forming member 50 into the inner periphery of the base end of the lower member 40 and engaging the annular protrusion 44 of the lower member 40 with the engaging groove 54 of the valve seat forming member 50. As a result, a second assembly 15B consisting of two parts, the lower member 40 and the valve seat forming member 50, is assembled.

[0093] Then, after aligning each of the engagement pieces 43 of the lower member 40 constituting the second assembly 15B with the corresponding engagement pieces 62 of the upper member 60 constituting the first assembly 15A, the first assembly 15A is pushed into the second assembly 15B as shown by arrow F in Figure 11.

[0094] Then, as shown in Figure 12, multiple engagement pieces 62 of the upper member 60 are inserted into the tubular portion 41 of the lower member 40, and the engagement claws 63 engage with the engagement holes 43a of the corresponding engagement pieces 43 on the lower member 40 side, thereby assembling the first assembly 15A and the second assembly 15B to each other and assembling the valve unit 15.

[0095] In this state, the flange portion 72 of the valve body 70, biased by the coil spring 90, is biased toward the valve seat 53 of the valve seat forming member 50, and the sealing protrusion 73 on the back side of the flange portion 72 of the valve body 70 abuts against the valve seat 53, thereby blocking the air vent 52 (see Figure 12).

[0096] Also, as shown in Figure 12, the cover member 30 can be attached to the seal member 20 by inserting the attachment protrusion 33 of the cover member 30 into the attachment groove 24 of the seal member 20 and clamping it between the pair of annular protrusions 22, 23.

[0097] 12, when the valve unit 15 is pushed in the insertion direction F, the cylindrical portion 41 of the lower member 40 is inserted into the main body portion 21 of the seal member 20. Thereafter, as shown in FIG. 13, the base member side engaging portion 45 of the lower member 40 engages with the rear peripheral edge portion of the temporary engaging portion 25 of the seal member 20, and the pressing portion 41a engages with the inner periphery of the main body portion 21, so that the valve unit 15 is temporarily held in the seal member 20 at a relatively shallow insertion position.

[0098] As a result, the release valve 10 is formed, which is made up of the valve unit 15 and the seal member 20. In this temporarily held state, the retaining portion 27 is able to bend and deform inward of the seal member 20. Note that the release valve 10 in this embodiment is designed to be transported in a state in which the valve unit 15 is temporarily held by the seal member 20.

[0099] Then, the release valve 10 is aligned with the case opening 3, and is inserted from the front side of the case opening 3, as shown by arrow F in Fig. 13. Then, the engaging protrusion 29 of the seal member 20 is pressed against the inner periphery of the case opening 3, and the retaining portion 27 is flexibly deformed inward of the seal member 20. Thereafter, the release valve 10 is pushed into the case opening 3 until the annular protrusion 22 of the seal member 20 abuts against the front peripheral edge 4 of the case opening 3, and when the engaging protrusion 29 of the seal member 20 comes out of the back opening of the cylindrical portion 3a of the case opening 3, the retaining portion 27 of the seal member 20 elastically returns to its original state.

[0100] 14, the engaging protrusion 29 of the retaining portion 27 is disposed with a slight gap relative to the rear end surface of the cylindrical portion 3a of the case opening 3, temporarily fixing the seal member 20 to the case opening 3, and ultimately temporarily fixing the release valve 10 to the case opening 3. Note that even in this state, the retaining portion 27 is still able to bend and deform inward of the seal member 20.

[0101] 14, the valve unit 15 is pushed into the seal member 20 temporarily fixed to the case opening 3. In this case, the valve unit 15 is pushed in until the flange portion 42 of the lower member 40 abuts against the annular protrusion 22 of the main body portion 21 of the seal member 20 and the temporary engagement portion 25. Then, the base member side engagement portion 45 of the lower member 40 is released from the temporary engagement portion 25 of the seal member 20, and the base member side engagement portion 45 is inserted into the main engagement portion 26 of the seal member 20.

[0102] 15, base member side engaging portion 45 engages with the inner peripheral surface of the axial tip side of main engaging portion 26, and pressing protrusion 28 is pressed against tubular portion 41 of lower member 40, preventing portion 27 from being bent and deformed outward from seal member 20, and engaging protrusion 29 engages with the rear peripheral edge of tubular portion 3a of case opening 3. In other words, preventing portion 27 is pressed outward via pressing protrusion 28, and engaging protrusion 29 provided on the outer periphery of preventing portion 27 is pressed firmly against the rear peripheral edge of tubular portion 3a of case opening 3, so that engaging protrusion 29 engages with the rear peripheral edge of tubular portion 3a of case opening 3 without any gap.

[0103] As a result, the valve unit 15 is finally fixed to the sealing member 20 at an insertion position deeper than the temporary holding state of the valve unit 15 shown in Figure 14, and the base end portion of the tubular portion 3a is clamped from the front side of the case opening 3 between the annular protrusion 22 of the sealing member 20 and the engaging protrusion 29 of the anti-slip portion 27, so that the valve unit 15 is finally fixed to the case opening 3 via the sealing member 20, as shown in Figure 15, and the entire release valve 10 can be attached to the case 1.

[0104] In this final fixed state, the cylindrical portion 41 of the lower member 40 is positioned inside the anti-slip portion 27, which prevents the anti-slip portion 27 from bending and deforming inwardly of the sealing member 20, restricting its reduction in diameter and keeping the engaging protrusion 29 of the anti-slip portion 27 engaged with the rear peripheral edge of the cylindrical portion 3a of the case opening 3, thereby allowing the valve unit 15 to remain in a final fixed state relative to the case 1 via the sealing member 20.

[0105] In this release valve 10, when the valve unit 15 and the seal member 20 are inserted into the case opening 3 of the case 1 in a temporary holding state in which the temporary engagement portion 25 of the seal member 20 is engaged with the base member side engagement portion 45 of the base member of the valve unit 15, as shown in Figure 13, the anti-detachment portion 27 of the seal member 20 can bend inward of the seal member 20, so that the seal member 20 can be easily inserted into the case opening 3 together with the valve unit 15 (see Figure 14).

[0106] In this state, as shown by arrow F in Figure 14, if valve unit 15 is inserted further and base member side engaging portion 45 of the base member engages with main engaging portion 26 of seal member 20, the base member will be positioned inside retaining portion 27 (here, tubular portion 41 of lower member 40 that constitutes the base member is positioned inside retaining portion 27), and the base member will prevent retaining portion 27 of seal member 20 from bending inward of seal member 20, restricting its diameter reduction, so that valve unit 15 can be firmly fixed to case opening 3 via seal member 20. As a result, a release valve 10 that is easy to attach to case 1 and difficult to remove from case 1 can be obtained.

[0107] 15, the valve body 70 is urged toward the valve seat forming member 50 by the coil spring 90 held in a compressed state within the base member, and the seal protrusion 73 on the back side of the flange portion 72 of the valve body 70 abuts against the valve seat 53, closing the vent hole 52. Furthermore, the cap 80 integrated with the valve body 70 is urged toward the cover member 30 via the coil spring 90, and the seal flange portion 85 abuts against the front side of the flange portion 32 of the cover member 30, closing the multiple openings 66 of the upper member 60.

[0108] When gas is generated inside the case due to the power storage device supplying power to the drive source or electrical components, or due to the external or internal environment of the case housing the power storage device, the device operates as follows (for example, when a power 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).

[0109] In other words, when the pressure in the internal space R1 of the case 1 rises and exceeds the biasing force of the coil spring 90, which is the biasing means, the valve body 70 slides in a direction away from the valve seat forming member 50 against the biasing force of the biasing means, and its flange portion 72 moves away from the valve seat 53.

[0110] 16, the vent hole 52 in the valve seat forming member 50 opens, and the cap 80 integrated with the valve body 70 moves away from the front side of the cover member 30 in conjunction with the valve body 70, opening the multiple openings 66 in the upper member 60. As a result, the internal space R1 and the external space R2 of the case 1 communicate with each other through the vent hole 52 in the valve seat forming member 50 and the multiple openings 66 in the upper member 60.

[0111] As a result, as shown by arrow L in Figure 16, gas in the internal space R1 of the case 1 passes through the case opening 3, the ventilation hole 52 of the valve seat forming member 50, and the opening 66 of the upper member 60 and is exhausted to the external space R2 of the case 1, thereby releasing (reducing) the pressure within the case 1.

[0112] In addition, in this embodiment, a protrusion (pressing protrusion 28) is provided on the inner surface of the sealing member 20, and this pressing protrusion 28 is configured to be pressed against the base member in a main fixed state in which the main engagement portion 26 of the sealing member 20 is engaged with the base member side engagement portion 45 of the base member, thereby expanding the diameter of the anti-slip portion 27.

[0113] According to this embodiment, in the fixed state in which the base member side engaging portion 45 of the base member is engaged with the main engaging portion 26 of the sealing member 20, the base member presses against the anti-slip portion 27, causing it to expand in diameter, thereby more firmly fixing the sealing member 20 to the case opening 3.

[0114] Furthermore, in this embodiment, the valve body 70 has a flange portion 72 that moves toward and away from the valve seat 53, and the base member has a lower member 40 on which the valve seat 53 is provided and an upper member 60 that is assembled to the lower member 40, with a cylindrical portion 67 formed on the upper member 60 side and a shaft portion 71 formed on the flange portion 72 that is inserted into the cylindrical portion 67 and supported to slide, and the biasing means consists of a coil spring 90, one end of which is supported by the flange portion 72 of the valve body 70 and the other end of which is supported by the upper member 60.

[0115] According to the above-described embodiment, the lower member 40 and the upper member 60 can be assembled while the coil spring 90, which serves as the biasing means, is kept compressed, thereby improving the ease of assembly of the valve unit 15. That is, by utilizing the shaft portion 71 of the valve body 70 and the tubular portion 67 that slidably supports it, the coil spring 90 can be maintained in a position along their axes (a straight position without tilting) and the lower member 40 and the upper member 60 can be assembled while compressing the coil spring 90, improving the ease of assembly of the valve unit 15 (if the position of the coil spring 90 cannot be maintained, the elastic force of the coil spring 90 will have an effect, making the assembly difficult). Furthermore, a similar effect can be obtained even when a tubular portion is formed on the flange portion side and a shaft portion that is inserted into the tubular portion and slidably supported is formed on the upper portion side.

[0116] (Another embodiment of a pressure release valve for an electricity storage device) 17 to 31 show other embodiments of the pressure release valve for an electricity storage device according to the present invention. Note that parts that are essentially the same as those in the above embodiment are given the same reference numerals and their description will be omitted.

[0117] As shown in FIG. 17, this pressure release valve 10A for an electricity storage device (hereinafter also simply referred to as "release valve 10A") has a fixing member 16 and a valve unit 17 that is slidably inserted inside the fixing member 16.

[0118] In addition, the fixing member 16 in this embodiment has a grommet 90A having an insertion portion 92 into the case opening 3, and a sealing member that is softer than the grommet 90A and is attached to the outer periphery of the grommet 90A to seal the outer peripheral edge of the case opening 3, and a retaining portion 110 is formed in the insertion portion 92, and the valve unit 17 is inserted inside the insertion portion 92.

[0119] More specifically, the fixing member 16 of this embodiment is composed of a grommet 90A having the above-mentioned insertion portion 92 and anti-slip portion 110, a first sealing member 20A attached to the base end side of the grommet 90A and constituting the above-mentioned sealing member, and a cover member 120 attached to the tip end side of the grommet 90A.

[0120] On the other hand, the valve unit 17 has an air vent 132 that connects the case internal space R1 and the case external space R2, a valve seat (first seal portion 86 described later) provided on the periphery of the air vent 132, an engaged portion that engages with the fixed member at a predetermined position, a valve body 60A that opens and closes the air vent 132, and a biasing means that biases the valve body 60A toward the valve seat.

[0121] More specifically, the valve unit 17 in this embodiment is composed of a pushing member 130 that can be pushed into the grommet 90A and that restricts the deflection deformation of the retaining portion 110 toward the inside of the base member, the valve body 60A, and a cap member 140 that supports one end 5a of the coil spring 5 and pushes the pushing member 130 through the second seal member 80A.

[0122] The pushing member 130 is made up of a pushing member body 130A and a second seal member 80A attached to the pushing member body 130A.

[0123] Furthermore, in this embodiment, a pushing member 130 constituting the valve unit 17 is inserted inside the insertion portion 91 of the grommet 90A so as to be slidable from a temporary holding position in the temporary holding state to a final fixing position in the final fixing state, and the pushing member 130 has a first seal portion 86A which forms a valve seat against which the valve body 60A contacts and separates, and a second seal portion 87 which slides against the inner circumference of the insertion portion 92.

[0124] In addition, the "engaged portion" in the present invention has different shapes, structures, and layouts for a temporary holding portion that temporarily holds the valve unit 17 to the fixed member 16 and a final fixing portion that permanently fixes the valve unit 17 to the fixed member 16.

[0125] 26, the "engaged portion" for temporary retention means, in this embodiment, the base end portion of the engaging claw 145 and the peripheral wall 131, which will be described later, and these engage with the temporary engagement surface 103 and the receiving portion 113, which will be described later, respectively, thereby holding the valve unit 17 in a temporary retention state relative to the fixed member 16. In this embodiment, the temporary engagement surface 103 and the receiving portion 113 form the "temporary engagement portion" of the present invention, which will be described later.

[0126] Meanwhile, the "engaged portion" for proper fixing in this embodiment refers to the engaging claw 145 (see FIG. 27), the engaging claw 134 (see FIG. 28), and the ridge 135 (see FIG. 29).

[0127] Then, as shown in Figure 27, the engagement claw 145 engages with the main engagement surface 107 described later, and as shown in Figure 28, the engagement claw 134 engages with the engagement protrusion 114 described later, and as shown in Figure 29, the tip end of the extension direction of the protrusion 135 abuts against and engages with the lower end surface of the positioning groove 115 described later (note that the abutment of the protrusion 135 against the positioning groove 115 also serves to regulate the pushing of the valve unit 17 against the fixing member 16), thereby holding the valve unit 17 in the main fixed state relative to the fixing member 16.

[0128] That is, in this embodiment, the main engagement surface 107, the engagement projection 114, and the positioning groove 115 form a "main engagement portion" of the present invention, which will be described later.

[0129] 23, the two parts, pusher member main body 130A and second seal member 80A, are assembled to form pusher member 130, and the two parts, grommet 90A and first seal member 20A, are assembled to form assembly 17A. Furthermore, as shown in FIG. 19, the two parts, pusher member 130 and assembly 17A, are assembled to form assembly 18A.

[0130] First, the grommet 90A will be described with reference to FIGS.

[0131] More specifically, the grommet 90A has a generally cylindrical insertion portion 91 to be inserted into the case opening 3, a generally annular bottom plate 93 that extends radially outward from the outer circumferential surface of the insertion portion 91 near the tip, a generally annular top plate 94 that is also disposed opposite the bottom plate 93 with a predetermined gap between them, and a plurality of connecting pieces 95 that connect the two plate portions 93, 94 to each other. The insertion portion 91 also has a protrusion 91a that protrudes a predetermined height from the inner peripheral edge of the bottom plate 93 toward the top plate 94.

[0132] Each connecting piece 95 is in the form of a plate extending radially across each plate portion 93, 94, and all connecting pieces 95 extend in the same direction. The opening 97 is provided between adjacent connecting pieces 95, 95 in the circumferential direction and the bottom plate portion 93 and the ceiling plate portion 94. This opening 97 radially connects the internal space and the external space of the grommet 90A.

[0133] Furthermore, first plate-like pieces 98 extending in the same direction as the connecting pieces 95 are provided between the connecting pieces 95 located at two radially opposing positions on both plate portions 93, 94. Furthermore, the first plate-like piece 98 and the connecting pieces 95, 95 located on both sides thereof are connected to each other by second plate-like pieces 99 located closer to the ceiling plate portion 94 and extending across the pieces 95, 98, and these portions as a whole form a substantially lattice shape.

[0134] Furthermore, third plate-like pieces 100 protrude from the outer surfaces of a pair of connecting pieces 95, 95 arranged orthogonally to the pair of first plate-like pieces 98, 98, perpendicular to the extending direction of the connecting pieces 95. Furthermore, fourth plate-like pieces 101 protrude from both sides of the base end of each third plate-like piece 100.

[0135] The locking claws 128 of the cover member 120 are adapted to lock onto the base end surfaces (rear surfaces of the base ends) of the first plate piece 98 and the third plate piece 100 (see FIG. 26).

[0136] Furthermore, notches 102 are formed on the inner peripheral edge of the ceiling plate portion 94 at the locations where the first plate piece 98 and the second plate piece 99 are provided and at the locations where the third plate piece 100 and the fourth plate piece 101 are provided, allowing the engagement pieces 144 of the cap member 140 to be inserted therethrough. Here, four notches 102 are formed at equal intervals in the circumferential direction.

[0137] In addition, a temporary engagement surface 103 is provided on the back surface of the ceiling plate portion 94, at the inner peripheral edge of the notch 102, with which the engagement claws 145 of the cap member 140 engage to temporarily hold the cap member 140 in a protruding state from the surface of the ceiling plate portion 94 of the grommet 90A (see Figure 25).

[0138] Positioning protrusions 104, which are inserted into positioning holes 123a (see FIG. 20) of the cover member 120, protrude from the surface of the outer circumferential edge of the ceiling plate portion 94 at positions corresponding to the notches 102. Furthermore, guide grooves 105, which guide guide ribs 121a of the cover member 120, are formed on the outer circumferential edge of the ceiling plate portion 94 between adjacent positioning protrusions 104, 104 in the circumferential direction.

[0139] In addition, a permanent engagement protrusion 106 protrudes from the inner surface of the second plate-like piece 99 at a position spaced from the temporary engagement surface 103, and from the inner surface of the connecting piece 95 from which the third plate-like piece 100 protrudes at a position at the same height as the second plate-like piece 99.

[0140] The back surface of each of the main engagement protrusions 106 forms a main engagement surface 107. As shown in Fig. 27, when the engagement claws 145 of the cap member 140 engage with the main engagement surface 107, the cap member 140 is main engaged with the grommet 90A in a state where the surface of the ceiling plate 141 of the cap member 140 is flush with the surface of the ceiling wall 123 of the cover member 120 (a state where the cap member 140 does not protrude from the ceiling surface of the grommet 90A or the cover member 120).

[0141] A pair of parallel slits 109, 109 are formed in the axial base end of the insertion portion 91, and a flexible retaining portion 110 is formed via the pair of slits 109, 109. In this embodiment, four retaining portions 110 are formed at equal intervals around the circumference of the insertion portion 91.

[0142] An engagement portion 111 projects from the outer periphery of the tip of each retaining portion 110 in the extension direction, and engages with the periphery of the back side of the case opening 3. The outer surfaces of the base and tip of the engagement portion 111 are tapered from the apex. In addition, a raised portion 112 is provided on the inner periphery of the tip of the retaining portion 110, which raised radially inward of the insertion portion 91.

[0143] When cap member 140 is temporarily held in grommet 90A and pusher member 130 is not pushed in by cap member 140, peripheral wall 131 of pusher member body 130A is not positioned inside protrusion 112 (see FIG. 26), and protrusion 112 is radially spaced from peripheral wall 131. Therefore, each retaining portion 110 can be flexibly deformed radially inward of insertion portion 91, allowing insertion portion 91 to be inserted from the front side to the back side of case opening 3 (see FIG. 26).

[0144] 27, when cap member 140 is fully engaged with grommet 90A, cap member 140 pushes in pusher member 130, and as a result, peripheral wall 131 of pusher member body 130A is positioned inside raised portions 112, and raised portions 112 come close to peripheral wall 131. This prevents each retaining portion 110 from bending radially inward of insertion portion 91, preventing insertion portion 91 from being pulled out of case opening 3 and holding grommet 90A in place at case opening 3.

[0145] Furthermore, a plurality of receiving portions 113, which form protrusions extending a predetermined length in the circumferential direction, are provided on the inner peripheral surface of the insertion portion 91 closer to the base end than the bottom plate portion 93 at a predetermined height. When the cap member 140 is temporarily held in the grommet 90A, these receiving portions 113 receive the base end of the peripheral wall 131 of the pushing member main body 130A (see FIG. 24), and hold the peripheral wall 131 of the pushing member main body 130A so that it is not positioned inside the raised portion 112 of the retaining portion 110.

[0146] Furthermore, multiple engagement protrusions 114 protrude from the inner surface of the insertion portion 91 closer to the base end than the bottom plate portion 93, at a position closer to the base end (tip in the extension direction) of the insertion portion 91 than the receiving portion 113.

[0147] Then, when the cap member 140 is fully engaged with the grommet 90A and the pushing member 130 is pushed in through the second seal member 80A, and the peripheral wall 131 of the pushing member main body 130A is positioned inside the raised portion 112 of the anti-slip portion 110 (see Figure 27), each engaging protrusion 114 can be engaged with a predetermined engaging claw 134 (see Figure 21) provided on the pushing member main body 130A, thereby holding the pushing member 130 in that position.

[0148] Furthermore, a plurality of positioning grooves 115, each having a concave groove shape and extending along the axial direction, are formed at predetermined positions on the inner peripheral surface of insertion portion 91 closer to the base end than bottom plate portion 93. A predetermined ridge 135 (see FIG. 22) provided on pushing member 130 is inserted into each positioning groove 115, which serves as a pushing guide when pushing pushing member 130 into grommet 90A and restricts the rotation of pushing member 130 relative to grommet 90A. Furthermore, the ridge 135 abuts against the lower end surface of the ridge 135, thereby restricting the pushing of pushing member 130 into grommet 90A (see FIG. 29).

[0149] Next, with reference to Figures 17 and 23, the first seal member 20A attached to the base end side of the grommet 90A will be described.

[0150] The first seal member 20A of this embodiment has a substantially circular plate-shaped main body 21. Thin, annular seal flanges 22A and 24A extend obliquely outward from the outer periphery of the main body 21 so as to be spaced apart from each other. One seal flange 22A elastically abuts against the peripheral edge of the front side of the case opening 3 (see FIG. 27), and the other seal flange 24A elastically abuts against the rear surface of the bottom plate 93 of the grommet 90A (see FIG. 23).

[0151] Furthermore, a plurality of annular seal projections 29A are provided to project from the rear and front surfaces of the main body 21.

[0152] Then, as shown in Figure 23, by placing the first sealing member 20A on the outer periphery of the tip of the insertion portion 91 of the grommet 90A, the inner peripheral edge of the main body portion 21 abuts against the outer periphery of the tip of the insertion portion 91, and a pair of sealing protrusions 29A, 29A on the surface side of the main body portion 21 abuts against the back surface of the bottom plate portion 93 of the grommet 90A, thereby attaching the first sealing member 20A to the grommet 90A.

[0153] Furthermore, when the insertion portion 91 of the grommet 90A is inserted from the front side of the case opening 3, and each engagement portion 111 on the outer periphery of the flexible piece engages with the rear peripheral edge of the case opening 3, as shown in Figure 27, when the release valve 10A is attached to the case opening 3, the seal flange portion 22A of the first seal member 20A abuts against the front peripheral edge of the case opening 3, and a pair of seal protrusions 29A, 29A on the rear side of the main body portion 21 abut.

[0154] Next, with reference to Figures 20 and 25, etc., a description will be given of the cover member 120 attached to the tip end side of the grommet 90A.

[0155] The cover member 120 of this embodiment has a substantially cylindrical peripheral wall 121 and a ceiling wall 123 that protrudes in the shape of an annular flange from the inner periphery of the tip of the peripheral wall 121. The peripheral wall 121 is positioned outside the surface opening of the opening 97 of the grommet 90A, and the ceiling wall 123 is positioned on the front side of the ceiling plate portion 94 of the grommet 90A.

[0156] Additionally, a plurality of positioning holes 123a are formed at equal intervals in the circumferential direction on the outer peripheral edge side of the ceiling wall 123. Positioning protrusions 104 (see FIG. 19) provided on the grommet 90A are inserted into each positioning hole 123a, and the rotation of the cover member 120 relative to the grommet 90A is restricted.

[0157] Furthermore, a plurality of guide ribs 121a are provided at equal intervals in the circumferential direction on the inner periphery of the peripheral wall 121, extending along the axial direction of the peripheral wall 121. Each guide rib 121a is inserted into a guide groove 105 provided in the grommet 90A, and serves to guide the cover member 120 when it is assembled to the grommet 90A, and to restrict the rotation of the cover member 120 relative to the grommet 90A.

[0158] Furthermore, a plurality of substantially L-shaped slits 124 consisting of a groove extending in the circumferential direction and a groove extending in the axial direction are formed at the base end of the peripheral wall 121, and a plurality of long plate-like pieces 125 that are capable of being deformed by flexure are provided via each slit 124. As shown in Fig. 31, each plate-like piece 125 can open and close a substantially long hole-shaped opening portion 127 via a fixed end portion 126 that is in the form of a thin hinge.

[0159] Furthermore, a plurality of locking claws 128 protrude from the inner periphery of the base end of the peripheral wall 121. As shown in Fig. 26, these locking claws 128 are adapted to lock onto the base end surfaces of the first plate piece 98 and the third plate piece 100 of the grommet 90A.

[0160] When the cover member 120 is attached to the grommet 90A, a gap 129 is formed between the base end of the peripheral wall 121 of the cover member 120 and the bottom plate portion 93 of the grommet 90A (see Figures 27 and 28), and the gap 129 is connected to the opening 97.

[0161] Next, with reference to Figures 21 and 23, a description will be given of a push-in member 130 that can be pushed into grommet 90A and that restricts deflection of retaining portion 110 toward the inside of the base member.

[0162] Pusher member body 130A constituting pusher member 130 has a substantially cylindrical peripheral wall 131. An inner peripheral opening of peripheral wall 131 forms ventilation port 132 that connects case internal space R1 and case external space R2.

[0163] A pair of slits 133a, 133a are formed parallel to each other from the axial base end edge of the peripheral wall 131 toward the axial tip end side, and a flexible piece 133 is formed via the pair of slits 133a, 133a. A plurality of these flexible pieces 133 are formed at predetermined intervals in the circumferential direction of the peripheral wall 131.

[0164] Furthermore, an engagement claw 134 protrudes from the outer periphery of the tip end in the extension direction of each flexible piece 133. When push-in member 130 is pushed through second seal member 80A and peripheral wall 131 of push-in member 130 is positioned inside raised portion 112 of retaining portion 110, each engagement claw 134 can engage with engagement protrusion 114 provided on grommet 90A, thereby holding push-in member 130 in the above position.

[0165] Furthermore, a plurality of ridges 135 extend axially at equal intervals around the outer periphery of peripheral wall 131. Each ridge 135 is inserted into a predetermined positioning groove 115 formed in grommet 90A to guide pushing member 130 into grommet 90A, restrict the rotation of pushing member 130 relative to grommet 90A, and, by abutting against the lower end surface of positioning groove 115, restrict the pushing of pushing member 130 into grommet 90A (see FIG. 29).

[0166] Additionally, a mounting protrusion 136 for mounting the second seal member 80A is provided at the tip end of the peripheral wall 131. Furthermore, a generally cross-shaped cap receiving portion 137 is provided on the inner periphery of the base end portion of the peripheral wall 131. Additionally, as shown in Figure 21, a valve body receiving portion 138 for receiving the bottom portion of the valve body 60A is formed on the upper surface side of the cap receiving portion 137.

[0167] Next, the second seal member 80A attached to the pushing member body 130A will be described with reference to FIGS.

[0168] The second seal member 80A of this embodiment has a generally cylindrical tubular portion 81A, and a mounting groove 85A is formed on the inner periphery thereof. As shown in Fig. 23, the mounting protrusion 136 of the pushing member 130 is inserted into the mounting groove 85A, whereby the second seal member 80A is mounted on the outer periphery of the tip end of the pushing member main body 130A.

[0169] A first seal portion 86 having an annular projection and serving as a valve seat protrudes from the inner peripheral edge of the axial tip of the cylindrical portion 81A. A second seal surface 65A provided on the valve body 60A comes into contact with and separates from this first seal portion 86 to open and close the vent port 132 (see FIGS. 27 and 30).

[0170] Furthermore, a second seal portion 87 having an annular projection projects from the outer periphery of the base end of the cylindrical portion 81A. As shown in Figures 27 and 28, this second seal portion 87 elastically contacts the inner circumferential surface of the insertion portion 91 of the grommet 90A to seal the gap between the insertion portion 91 and the second seal member 80A.

[0171] Next, with reference to FIGS. 22 and 24, the cap member 140 that supports one end 5a of the coil spring 5 and pushes the push-in member 130 through the second seal member 80A will be described.

[0172] The cap member 140 of this embodiment has a ceiling plate 141 having an approximately circular plate shape, a peripheral wall 142 extending vertically from the outer peripheral edge of the ceiling plate 141 by a predetermined length, and a tubular portion 143 having an approximately cylindrical shape protruding from the center of the back surface of the ceiling plate 141.

[0173] 25, one end of the coil spring 5 is inserted inside the cylindrical portion 143, and one end 5a of the coil spring 5 is supported at the center of the back surface of the ceiling plate 141. Also, as shown in FIGS. 27 and 30, the cylindrical portion 143 is disposed on the inner periphery of the cylindrical portion 61A of the valve body 60A, and guides the sliding movement of the valve body 60A that slides up and down relative to the cap member 140.

[0174] Furthermore, a plurality of (four in this example) engagement pieces 144 extend at equal intervals in the circumferential direction from the leading end of the peripheral wall 142. Each engagement piece 144 extends from the leading end of the peripheral wall in a direction away from the ceiling plate 141, and is folded back via a curved bent portion 144a in a direction approaching the ceiling plate 141, forming a generally U-shape as a whole.

[0175] Furthermore, an engagement claw 145 protrudes from the outer periphery of the tip of each engagement piece 144. As shown in Fig. 25, the engagement claw 145 engages with the temporary engagement surface 103 of the grommet 90A, thereby temporarily holding the cap member 140 to the grommet 90A. On the other hand, as shown in Fig. 27, the engagement claw 145 engages with the main engagement surface 107 of the main engagement projection 106 of the grommet 90A, thereby finally engaging the cap member 140 to the grommet 90A.

[0176] Furthermore, as shown in Figure 24, a plurality of long pressure plates 146 are vertically attached to the back surface of the ceiling plate 141 at a location slightly offset radially inward from the outer peripheral edge of the ceiling plate 141.

[0177] Each pressing plate 146 presses the outer peripheral edge portion of the second sealing member 80A at the axial tip side of the tubular portion 81A, and when the cap member 140 is pressed into the grommet 90A, it indirectly presses the pushing member 130 via the second sealing member 80A.

[0178] Furthermore, plate-shaped ribs 147 and 148 extend from the outer surface of each pressure plate 146 at the center in the width direction so as to be perpendicular to the pressure plate 146 .

[0179] The rib 147 is provided between a predetermined engagement piece 144 and a pressure plate 146 at a position corresponding to the engagement piece 144, and at the tip end thereof, a receiving portion 147a is formed to receive the protrusion 91a of the insertion portion 91 of the grommet 90A (see Figures 24 and 27).

[0180] As shown in FIG. 22, a receiving portion 148a is also formed at the tip of the rib 148 located between the circumferentially adjacent engagement pieces 144, 144, for receiving the protrusion 91a of the insertion portion 91 of the grommet 90A.

[0181] Next, the valve body 60A will be described with reference to FIGS.

[0182] The valve body 60A of this embodiment has a tubular portion 61A having an approximately cylindrical shape, a flange portion 62A having an approximately circular plate shape that protrudes from the outer periphery of the tubular portion 61A near the tip end, and a spring support portion 63A having an approximately hat shape that is provided on the inner periphery of the base end of the tubular portion 61A.

[0183] The cylindrical portion 61A is disposed on the outer periphery of the cylindrical portion 143 of the pushing member main body 130A, and guides the up-down sliding movement of the valve body 60A (see FIGS. 27 and 30). The spring support portion 63A is inserted into the inner periphery of the other end of the coil spring 5, and abuts against the other end 5b of the coil spring 5 to support the other end of the coil spring 5 (see FIG. 27).

[0184] Furthermore, an annular protrusion protrudes from the back surface of the outer peripheral edge of the flange portion 62A, and the back surface of the annular protrusion forms a second seal surface 65A that abuts against the peripheral edge of the ventilation hole 132 (contacts and separates from the first seal portion 86).

[0185] As shown in Figure 27, the second sealing surface 65A is positioned closer to the external space R2 of the case 1 than the first sealing surface 28A, which is made up of the back surface of the sealing flange portion 22A and the back surfaces of the pair of sealing protrusions 29A, 29A.

[0186] Furthermore, as shown in Figure 28, when the second seal surface 65A is at its maximum distance from the first seal portion 86, the second seal surface 65A is configured to be positioned closer to the case external space R2 than the inner edge portion 97a of the opening 97 provided in the grommet 90A, which is closest to the case internal space R1.

[0187] (Action and effect) Next, the function and effect of the release valve 10A having the above-described structure will be described.

[0188] First, the assembly process of the release valve 10A will be described.

[0189] First, the mounting protrusion 136 of the pushing member main body 130A is inserted into the mounting groove 85A of the second seal member 80A to mount the second seal member 80A on the outer periphery of the tip of the pushing member main body 130A, thereby assembling the pushing member 130 (see FIG. 23). Then, the first seal member 20A is placed on the outer periphery of the tip of the insertion portion 91 of the grommet 90A, thereby mounting the first seal member 20A to the grommet 90A, thereby assembling the assembly 17A (see FIG. 23).

[0190] Next, pushing member 130 and assembly 17A are assembled. That is, the protrusions 135 of pushing member body 130A are aligned with the corresponding positioning grooves 115 of grommet 90A, and pushing member 130 is pushed into grommet 90A. Then, pushing member 130 is guided and pushed in by protrusions 135 inserted into positioning grooves 115.

[0191] Thereafter, the base end of the peripheral wall 131 of the pushing member main body 130A is received by the receiving portion 113 of the grommet 90A, restricting further pushing of the pushing member 130 and restricting rotation of the pushing member 130 relative to the grommet 90A, thereby assembling the assembly 18A (see Figure 24).

[0192] Furthermore, when the assembly 18A is assembled, the base end of the peripheral wall 131 of the pushing member main body 130A is retracted toward the tip of the insertion portion 91 of the grommet 90A rather than the base end of the insertion portion 91, and since the peripheral wall 131 of the pushing member main body 130A is not positioned inside the raised portion 112 of the anti-slip portion 110, each anti-slip portion 110 can be flexibly deformed inward toward the insertion portion 91.

[0193] Next, the valve body 60A is inserted through the upper opening of the grommet 90A, and the outer peripheral edge of the flange portion 62A of the valve body 60A is brought into contact with the first seal portion 86 of the second seal member 80A to support the valve body 60A. Thereafter, the other end of the coil spring 5 is supported by the spring support portion 63A of the valve body 60A.

[0194] Furthermore, the corresponding engagement pieces 144 of the cap member 140 are aligned with the respective notches 102 of the grommet 90A, and the cap member 140 is pushed into the grommet 90A. Then, one end of the coil spring 5 is inserted into and supported in the cylindrical portion 143 of the cap member 140, the engagement claws 145 of the engagement pieces 144 engage with the temporary engagement surface 103 of the grommet 90A, and the base end of the peripheral wall 131 engages with (is received by) the receiving portion 113, so that the cap member 140 is temporarily held in the grommet 90A (see FIG. 25).

[0195] Thereafter, the positioning protrusions 104 of the grommet 90A are aligned with the corresponding positioning holes 123a of the cover member 120, and the cover member 120 is pushed into the grommet 90A. Then, the cover member 120 is pushed into the grommet 90A while being guided by the guide ribs 121a inserted into the guide grooves 105.

[0196] Then, each locking claw 128 of the cover member 120 locks onto the base end surfaces of the first plate-like piece 98 and the third plate-like piece 100 of the grommet 90A, and each positioning protrusion 104 of the grommet 90A is inserted into the corresponding positioning hole 123a of the cover member 120, thereby attaching the cover member 120 to the grommet 90A in a state where rotation is restricted (see Figure 26).

[0197] In the above state, the cap member 140 is temporarily held in the grommet 90A, the pushing member 130 is not pressed by the cap member 140, and the peripheral wall 131 of the pushing member 130 is not positioned inside the raised portion 112, so each anti-slip portion 110 can be flexibly deformed radially inward of the insertion portion 91.

[0198] 26, the release valve 10A is inserted from the front side of the case opening 3. Then, the tapered outer surface of the base of the engaging portion 111 of the grommet 90A is pressed against the inner periphery of the case opening 3, and the retaining portion 110 is bent and deformed inward of the insertion portion 91.

[0199] Thereafter, the release valve 10 is pushed into the case opening 3 until the seal flange portion 22A of the first seal member 20A and the pair of seal protrusions 29A, 29A abut against the front peripheral edge of the case opening 3, and when the top of the engagement portion 111 comes out of the back opening of the case opening 3, the anti-slip portion 110 elastically returns to its original position, and the outer surface of the tapered tip of the engagement portion 111 engages with the back peripheral edge of the case opening 3, and the release valve 10A is temporarily fixed to the case opening 3.

[0200] From the above state, the cap member 140 is pushed into the grommet 90A in the insertion direction F. Then, the multiple pressing plates 146 of the cap member 140 press the second seal member 80A, and the pushing member 130 is pushed in through the second seal member 80A.

[0201] Thereafter, when pushing member 130 is pushed in until the tip of protrusion 135 abuts against the lower end surface of positioning groove 115, the base end of peripheral wall 131 of pushing member body 130A is positioned inside raised portion 112 of retaining portion 110 of grommet 90A, and engagement claw 134 of flexible piece 133 of pushing member 130 engages with engagement protrusion 114 of grommet 90A (see FIG. 28). At the same time, engagement claw 145 of cap member 140 engages with main engagement surface 107 of main engagement protrusion 106 (see FIG. 27). Furthermore, the tip of protrusion 135 abuts against and engages with the lower end surface of positioning groove 115 (see FIG. 29).

[0202] As a result, the cap member 140 is fully engaged with the grommet 90A, and the release valve 10A can be fully fixed to the case opening 3 as shown in FIG.

[0203] 27, peripheral wall 131 of push-in member 130 is located inside raised portion 112 of retaining portion 110 of grommet 90A, so each retaining portion 110 cannot bend or deform inward of insertion portion 91. As a result, grommet 90A is held in place against case opening 3, and release valve 10A can be maintained in a state where it is firmly fixed to case opening 3.

[0204] 24 and 27, the cap member 140 has a generally U-shaped engagement piece 144, and a receiving portion 147a that receives the protruding portion 91a of the insertion portion 91 of the grommet 90A is formed between a base end portion 144b of the engagement piece 144 and the pressing plate 146. When the valve unit 17 is finally fixed to the fixing member 16 and the protruding portion 91a is received in the receiving portion 147a, the base end portion 144b of the engagement piece 144 is positioned slightly spaced from the outer periphery of the protruding portion 91a of the cylindrical wall portion 91.

[0205] Therefore, when the valve unit 17 is temporarily held to the fixing member 16, the protrusion 91a can be easily received within the receiving portion 147a. Furthermore, if a force acts in a direction that moves the valve unit 17 away from the fixing member 16 while the valve unit 17 is permanently fixed to the fixing member 16, the engaging piece 144 is flexibly deformed inward of the cover member, and the base end portion 144b thereof comes into contact with the protrusion 91a, making it difficult for the protrusion 91a to come out of the receiving portion 147a.

[0206] That is, the valve unit 17 can be easily temporarily held by the fixing member 16, and after the valve unit 17 is permanently fixed to the fixing member 16, the valve unit 17 can be made less likely to come off from the fixing member 16.

[0207] Furthermore, as shown in FIG. 26, when the valve unit 17 is temporarily held by the fixing member 16, the second seal portion 87 provided on the second seal member 80A abuts against the inner periphery of the insertion portion 91 of the grommet 90A, thereby improving the sealing performance in the temporarily held state.

[0208] Furthermore, in the state shown in Figure 27, the coil spring 5 held in a compressed state between the cap member 140 and the valve body 60A urges the second seal surface 65A of the valve body 60A toward the first seal portion 86 provided on the second seal member 80A, causing the second seal surface 65A to abut against the first seal portion 86, thereby blocking the ventilation hole 132.

[0209] Then, when the pressure in the internal space R1 of the case 1 rises and exceeds the biasing force of the coil spring 5, the valve body 60A slides in a direction away from the first seal portion 86 against the biasing force, and the second seal surface 65A moves away from the first seal portion 86.

[0210] 30, the ventilation hole 132 provided in the push-in member 130 opens, and the case internal space R1 and the case external space R2 communicate with each other through the ventilation hole 132. In this embodiment, the case internal space R1 and the housing internal space R3 communicate with each other through the ventilation hole 132, and the housing internal space R3 and the case external space R2 communicate with each other through the opening 97, the gap 129, etc.

[0211] Therefore, gas or other vapor in the case internal space R1 flows into the housing internal space R3 through the ventilation hole 132, passes through the gap between the engaging pieces 144, 144 of the cap member 140, passes over the inner edge 97a of the opening 97 of the grommet 90A (the tip end in the protruding direction of the protruding portion 91a of the insertion portion 91), passes through the opening 97, and is then exhausted from the gap 129 to the case external space R2 (see the arrow in FIG. 30). As a result, the pressure inside the case can be released.

[0212] In this embodiment, the cover member 120 has a structure including a peripheral wall 121 and a plate-like piece 125 formed in the peripheral wall 121 through a slit 124 so as to be able to flexibly deform. Therefore, for example, if a large amount of gas is generated in the case internal space R1 and the pressure in the case internal space R1 rises suddenly, the plate-like piece 125 flexes and deforms, as shown in FIG. 31, and the gas can be quickly discharged from its opening portion 127.

[0213] In this release valve 10A, when the fixing member 16 and the valve unit 17 are inserted into the case opening 3 in a temporary holding state in which the temporary engagement surface 103 and the receiving portion 113, which are temporary engagement portions, are engaged with the engaging claw 145 and the base end of the peripheral wall 131, which are engaged portions for temporarily holding the valve unit, the anti-slip portion 110 can bend toward the inside of the fixing member, so that the valve unit 17 can be easily inserted into the case opening 3 together with the fixing member 16.

[0214] In this state, when valve unit 17 is inserted further into fixing member 16 and engaging claws 145, 134, and ridges 135, which are engaged portions for permanently fixing the valve unit, with main engaging surfaces 107, engaging projections 114, and positioning grooves 115, which are main engaging portions (see Figures 27 to 29), valve unit 17 is positioned inside retaining portions 110, which prevent retaining portions 110 from bending toward the inside of the fixing member and restrict the reduction in diameter, so that valve unit 17 can be firmly fixed to case 1 via fixing member 16. As a result, a release valve 10A can be obtained that is easy to attach to case 1 and difficult to remove from case 1.

[0215] In addition, the fixing member 16 in this embodiment has a grommet 90A having an insertion portion 92 into the case opening 3, and a sealing member (first sealing member 20A) that is softer than the grommet 90A and is attached to the outer periphery of the grommet 90A to seal the outer peripheral edge of the case opening 3, and a retaining portion 110 is formed in the insertion portion 92, and the valve unit 17 is inserted inside the insertion portion 92.

[0216] According to the above embodiment, the retaining portion 110 is formed on the insertion portion 91 of the grommet 90A, which is harder than the first seal member 20A, so it is easier to determine whether the retaining portion 110 has been deflected or deformed than when the retaining portion is provided on a soft seal member, and it becomes clear that the release valve 10A has been fully fixed to the case opening 3. Furthermore, the retaining force of the retaining portion 110 on the case opening 3 can be improved compared to when the retaining portion is provided on a seal member.

[0217] Furthermore, in this embodiment, a pushing member 130 constituting the valve unit 17 is inserted inside the insertion portion 92 of the grommet 90A so as to be slidable from a temporary holding position in the temporary holding state to a final fixing position in the final fixing state, and the pushing member 130 has a first seal portion 86A which forms a valve seat against which the valve body 60A contacts and separates, and a second seal portion 87 which slides against the inner circumference of the insertion portion 92.

[0218] According to the above aspect, the second seal portion 87 slides against the inner circumference of the insertion portion 92 from the temporary holding state to the final fixed state of the pushing member 130, so that the sealing property between the fixing member 16 and the valve unit 17 (particularly, the sealing property between the inner circumference of the insertion portion 91 of the grommet 90A and the outer circumference of the peripheral wall 131 of the pushing member main body 130A) can be maintained, making it difficult for foreign matter such as water or dirt to enter the valve unit 17.

[0219] (Still another embodiment of the pressure release valve for the electricity storage device) 32 shows yet another embodiment of the pressure release valve for an electricity storage device according to the present invention. Note that parts that are substantially the same as those in the above embodiment are given the same reference numerals and their description will be omitted.

[0220] As shown in FIG. 32, a pressure release valve 10B for an electricity storage device (hereinafter also simply referred to as "release valve 10B") of this embodiment differs from the embodiments shown in FIGS. 17 to 31 in the shape of a cover member 120B.

[0221] That is, in the cover member 120B in this embodiment, openings 122 are formed between the tip end of the peripheral wall 121 and the ceiling wall 123, and a plurality of openings 122 are formed in the circumferential direction of the peripheral wall 121 and the ceiling wall 123. Each opening 122 communicates with the internal space of the cover member 120B.

[0222] Also in this embodiment, for example, when a large amount of gas is generated in the case internal space R1 and the pressure in the case internal space R1 rises suddenly, the gas can be quickly discharged from the plurality of openings 122.

[0223] 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]

[0224] 1 case 3 Case opening 10, 10A, 10B Pressure release valve (release valve) for power storage device 15,17 Valve unit 16 Fixing member 18 Push-in member 20 Sealing material 25 Temporary engagement portion 26 Main engagement part 27 Retaining part 28 Pressing protrusion 40 Lower member 45 base member side engagement portion 50 Valve seat forming member 52,132 vents 53 Valve seat 60 Upper member 67 Cylinder part 70 Valve body 71 Shaft 72 Flange 80 Cap 80A Second sealing member 86 First seal part 87 Second seal part 90 Coil spring 90A grommet 91 Insertion section 110 Retaining part

Claims

1. A pressure release valve for an electricity storage device, which is attached to a case that houses the electricity storage device, a fixing member that is inserted into and fixed to a case opening formed in the case; a valve unit slidably inserted into the fixing member, the valve unit includes a vent hole that connects the internal space and the external space of the case, a valve seat provided on the periphery of the vent hole, an engaged portion that engages with the fixed member at a predetermined position, a valve body that opens and closes the vent hole, and biasing means that biases the valve body toward the valve seat; The fixing member includes: a retaining portion that engages with the case; a temporary engagement portion that is provided inside the fixing member and that engages with the engaged portion at a predetermined insertion position when the valve unit is inserted into the fixing member, and a full engagement portion that engages with the engaged portion at an insertion position deeper than the temporary engagement portion, A pressure release valve for an electricity storage device, characterized in that the anti-slip portion is configured to bend inward in a temporary holding state in which the engaged portion is engaged with the temporary engaging portion, and to be configured so that the reduction in diameter is regulated by the valve unit in a final fixed state in which the engaged portion is engaged with the final engaging portion.

2. The fixing member is a grommet having an insertion portion into the case opening; a sealing member that is softer than the grommet and is attached to the outer periphery of the grommet to seal the front peripheral edge of the case opening, The pressure release valve for an electricity storage device according to claim 1 , wherein the retaining portion is formed in the insertion portion, and the valve unit is inserted into the insertion portion.

3. a push-in member constituting the valve unit is inserted inside the insertion portion of the grommet so as to be slidable from a temporary holding position in the temporary holding state to a final fixing position in the final fixing state; 3. The pressure release valve for an electric storage device according to claim 2, wherein the pushing member has a first seal portion that forms the valve seat against which the valve body comes into contact and a second seal portion that comes into sliding contact with the inner periphery of the insertion portion.

4. the fixing member is a cylindrical sealing member that is inserted into and fixed to a case opening formed in the case, The valve unit is inserted into the inside of the seal member and fixed to the case via the seal member, The valve unit includes: a base member having the vent hole and the valve seat, and further having the engaged portion that engages with the seal member, the valve body being slidable relative to the base member; an inner peripheral surface of the seal member is provided with the temporary engagement portion that engages with the engaged portion at a predetermined insertion position when the valve unit is inserted into the seal member, and the full engagement portion that engages with the engaged portion at an insertion position deeper than the temporary engagement portion, The sealing member is provided with a retaining portion that engages with the case, 2. A pressure release valve for an electricity storage device as described in claim 1, wherein the anti-slip portion is configured to bend inward in a temporary holding state in which the engaged portion is engaged with the temporary engaging portion, and to be regulated in diameter reduction by the base member in a final fixed state in which the engaged portion is engaged with the final engaging portion.

5. A protrusion is provided on the inner circumferential surface of the seal member, 5. The pressure release valve for an electricity storage device according to claim 4, wherein the protrusion is pressed against the base member in a fully fixed state in which the engaged portion is engaged with the fully engaging portion, thereby expanding the diameter of the retaining portion.

6. The valve body has a flange portion that comes into contact with and separates from the valve seat, the base member has a lower member provided with the valve seat and an upper member assembled to the lower member, a cylindrical portion is formed on one of the flange portion and the upper member, a shaft portion that is inserted into and slidably supported by the cylindrical portion is formed on the other of the flange portion and the upper member, 6. A pressure release valve for an electrical storage device according to claim 4 or 5, wherein the biasing means comprises a coil spring, is arranged on the outer periphery of the cylindrical portion, has one end supported by the flange portion of the valve body, and the other end supported by the upper member.

Images