GB2610044A - Gas discharge device for power storage device - Google Patents

Abstract

A gas discharge device 10 for a power storage device (1, Figure 10) is provided. The gas discharge device includes: a base member 20; a cap member 50; and a seal member 70. The cap member 50 includes: a lid portion 51; and a claw portion 61. The cap member 50 is configured such that when a gas pressure G is equal to or higher than a predetermined value, the cap member 50 becomes detached from the base member 20.The base member 20 is provided with a seal member attaching portion 31 to which the seal member 70 is to be attached, and a restricting wall 35 that is disposed on an outer periphery of the seal member attaching portion 31 and that is configured to restrict expansion of the seal member 70. When the gas pressure G is greater than the predetermined pressure the resulting displacement of the lid portion 51 causes the claw portion 61 to become detached from the base member 20 to allow the discharge of gas.

Description

GAS DISCHARGE DEVICE FOR POWER STORAGE DEVICE

TECHNICAL FIELD

[0001] The present invention relates to a gas discharge device for a power storage device that discharges a gas when a gas pressure at a gas discharge port of the power storage device is equal to or higher than a predetermined value

BACKGROUND ART

[0002] For example, a power storage device such as a battery or a condenser is used in a hybrid vehicle or an electric vehicle. For example, when the power storage device is a battery such as a lithium ion batten', a gas may be generated by a chemical reaction of an electrolytic solution. In this case, it is necessary to discharge the gas from the inside of the power storage device to the outside of the power storage device.

[0003] For example, Patent Literature 1 listed below describes a sealed lead-acid battery including a cylindrical liquid inlet protruding upward from a battery inner lid, and a cap valve formed in a cap shape having a ceiling plate and a peripheral wall suspended from a peripheral edge of the ceiling plate and detachably attached to a distal end of the liquid inlet, in which locking members are provided on an upper outer periphery of the liquid inlet and an inner periphery of an opening portion of the cap valve, respectively, so that the cap valve is hardly detached.

[0004] Specifically, on the upper outer periphery of the liquid inlet, a protruding portion (locking member) is provided, in which a tapered surface is formed on an outer surface and a locking surface having a horizontal surface shape is formed on a lower end surface. In addition, on an inner periphery of a lower end portion of the peripheral wall of the cap valve, a protruding portion (locking member) also is provided, in which a tapered surface is formed on an outer surface and a locking surface having a horizontal surface shape is formed on an upper end surface. Further, by covering the upper outer periphery of the liquid inlet with the cap valve, the locking surface of the protruding portion on a liquid inlet side and the locking surface of the protruding portion on a cap valve side are locked to each other, and the cap valve is attached to the liquid inlet. Then, when a gas pressure in the lead-acid battery becomes equal to or higher than a predetermined value, the cap valve is detached from the liquid inlet, and the gas in the lead-acid battery is discharged.

CITATION LIST

PATENT LITERATURE

[0005] Patent Literature 1: JP-A-H08-315799

SUMMARY OF INVENTION

TECHNICAL PROBLEM

[0006] In the case of the sealed lead-acid battery in the above Patent Literature I, the locking members are respectively provided on the upper outer periphery of the liquid inlet and the inner periphery of the opening portion of the cap valve, the horizontal locking surfaces of both the locking members are locked to each other, and the cap valve is hardly detached from the liquid inlet, and thus there is a disadvantage that the cap valve is hardly detached from the liquid inlet even when an internal pressure of the lead-acid battery increases, and the gas in the lead-acid battery is hardly discharged.

[0007] Therefore, an object of the present Invention is to provide a gas discharge device for a power storage device that is capable of maintaining sealing performance between a base member and a cap member, and at the time of increasing a gas pressure at a gas discharge port of the power storage device, reliably detaching the cap member from the base member.

SOLUTION TO PROBLEM

[0008] In order to achieve the above object, the present invention provides a gas discharge device for a power storage device that is configured to discharge a gas when a gas pressure at a gas discharge port of the power storage device is equal to or higher than a predetermined value. The gas discharge device includes: a base member configured to be fixed to the gas discharge port and having a passage configured to communicate with the gas discharge port inside the base member, a cap member to be detachably attached to the base member so as to close an outlet of the passage of the base member, and a seal member disposed between the base member and the cap member, and configured to seal a gap between the base member and the cap member. The cap member includes a lid portion disposed to face the outlet of the passage of the base member, and a claw portion to be engaged with the base member. The cap member is configured such that when the gas pressure at the gas discharge port is equal to or higher than the predetermined value, engagement of the claw portion with the base member is released by a pressure received by the lid portion, and the cap member is detached from the base member. The base member is provided with a seal member attaching portion to which the seal member is to be attached, and a restricting wall that is disposed on an outer periphery of the seal member and that is configured to restrict expansion of the seal member.

ADVANTAGEOUS EFFECTS OF INVENTION

[0009] According to the present invention, when the gas pressure at the gas discharge port of the power storage device becomes equal to or higher than the predetermined value, the lid portion of the cap member receives a gas pressure and is pressed by the gas pressure, when the engagement of the claw portion with the base member is released by the pressure received by the lid portion, the cap member is detached from the base member. At this time, the gas pressure is also applied to the seal member to expand the seal member, but the expansion of the seal member is restricted by restricting walls of the base member, and sealing performance between the base member and the cap member is maintained by the seal member, and thus, the gas pressure is firmly applied to the lid portion of the cap member, and the cap member can be reliably detached from the base member. Therefore, the sealing performance between the base member and the cap member can be maintained, and at the time of increasing the gas pressure at the gas discharge port, the cap member can be reliably detached from the base member, and the gas can be discharged from the power storage device.

BRIEF DESCRIPTION OF DRAWINGS

[0010] FIG. I is an exploded perspective view showing a gas discharge device for a power storage device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a state where each member of the gas discharge device for the power storage device is assembled.

FIG 3 is a front view of a base member constituting the gas discharge device for the power storage device FIG 4 is a side view of the base member.

FIG 5 is a bottom view of the base member.

FIG 6 is a bottom view showing a state where a seal member is attached to the base member FIG 7 is a cross-sectional view taken along a line A-A in FIG. 2.

FIG 8 is a cross-sectional view taken along a line B-B in FIG. 2.

FIG 9 is a cross-sectional view illustrating a state where a cap member is detached from the base member in the state of FIG. 8.

FIG. 10 is a perspective view for illustrating a place of use of the gas discharge device for the power storage device according to the present invention.

DESCRIPTION OF EMBODIMENTS

[0011] (Embodiment of Gas Discharge Device for Power Storage Device) Hereinafter, an embodiment of a gas discharge device for a power storage device according to the present invention will be described with reference to the drawings. [0012] As shown in FIG. 10, a gas discharge device 10 for a power storage device (hereinafter, also simply referred to as "discharge device 10") is for discharging a gas G when a gas pressure at a gas discharge port 6 (see FIGS. 7 to 9) of a power storage device 1 is equal to or higher than a predetermined value.

[0013] In a case of this embodiment, a plurality of power storage devices 1 are disposed in a case 2. Here, two power storage devices 1 are disposed in each of left and right regions in the case 2. A connector 3 communicating with an internal space of each power storage device 1 is attached to each power storage device I. The pair of power storage devices 1, 1 disposed in each of the left and right regions in the case 2 are connected to a common gas discharge tube 4 via the connectors 3, 3.

[0014] The gas discharge tubes 4 extend to the outside of the case 2 via tube holding members 5 made of rubber, sponge, or the like. That is, the gas discharge tubes 4, 4 extend outward from both left and right side walls of the case 2.

[0015] As shown in FIGS. 7 to 9, a gas discharge port 6 is provided at a distal end portion of each gas discharge tube 4 in an extending direction. In this embodiment, the gas discharge port 6 is disposed such that an opening thereof faces downward. Further, an attached member 7 having an attachment hole 7a is disposed at a position facing the gas discharge port 6, and the discharge device 10 is to be attached to the attachment hole 7a of the attached member 7 (see FIGS. 7 to 9).

[0016] Examples of the power storage device 1 include a battery (lithium ion battery or the like), a condenser, a capacitor, and the like used in a hybrid vehicle including a plug-in electric hybrid vehicle, an electric vehicle, and the like, but the power storage device 1 is not particularly limited thereto as long as the power storage device 1 is a device capable of storing power. A shape and a structure of the case, a shape and an arrangement number of the power storage device disposed in the case, and the like are not particularly limited.

[0017] As shown in FIGS. 1, 2, and 7 to 9, the discharge device 10 in this embodiment includes a base member 20 fixed to the gas discharge port 6 and having a passage 21 communicating with the gas discharge port 6 inside the base member 20, a cap member 50 detachably attached to the base member 20 so as to close an outlet 21b of the passage 21 of the base member 20, and a seal member 70 disposed between the base member 20 and the cap member 50 and sealing a gap between the base member 20 and the cap member 50.

[0018] The discharge device 10 further includes a seal washer 8 that is attached to the base member 20 and seals a gap between the attachment hole 7a of the attached member 7 and the base member 20.

[0019] The seal member 70 and the seal washer 8 are made of a porous material such as sponge or an elastic material such as rubber or elastic elastomer, and have an annular shape. In addition, the seal member 70 is pressed and compressed from an axial direction by an external force, a gas pressure, or the like, and can be deformed such as a thickness thereof being reduced, the seal member 70 being pressed from a radially inner side and expanded, or a diameter of the seal member 70 being reduced from a radially outer side. The seal member has a smaller diameter than that of the seal washer 8.

[0020] Next, a detailed configuration of the base member 20 will be described with reference to FIG. 1 and FIGS. 3 to 9.

[0021] As shown in FIGS. 7 to 9, the base member 20 of this embodiment has a substantially cylindrical shape as a whole in which the passage 21 is formed therein. An annular flange portion 23 extends from an outer periphery of the base member 20 in the middle in the axial direction. As shown in FIGS. 7 to 9, when the base member 20 is attached to the attachment hole 7a of the attached member 7, the seal washer 8 is sandwiched by the flange portion 23 and the attached member 7. Via the flange portion 23, a portion of the base member 20 on a proximal end side (one end side) in the extending direction of the base member 20 is formed as a connection portion 25, and a portion of the base member 20 on a distal end side (the other end side) in the extending direction of the base member 20 is formed as an insertion portion 27.

[0022] In the following description, the distal end side of the base member 20 means an end portion side where the cap member 50 is disposed, and the proximal end side of the base member 20 means an end portion side, opposite to the distal end side, where the gas discharge port 6 is disposed.

[0023] Further, by inserting the connection portion 25 into the gas discharge port 6 of the gas discharge tube 4, the base member 20 is connected and fixed to the gas discharge port 6. As shown in FIGS. 7 and 8, an insertion direction of the base member 20 into the gas discharge port 6 at this time is referred to as 'Fl". An annular protrusion shaped stopper portion 25a for restricting excessive insertion into the gas discharge port 6 is provided on an outer periphery of the connection portion 25 on the distal end side, and a plurality of annular protrusions 25b each having a tapered surface are provided on the outer periphery of the connection portion 25 on the proximal end side with respect to the stopper portion 25a (see FIGS. 3 and 4).

[0024] On the other hand, the insertion portion 27 is inserted into the attachment hole 7a of the attached member 7, and has a portion out of an opening of the attachment hole 7a on a back side (a side opposite to a front side which is a surface facing the flange portion 23). The insertion portion 27 has a substantially cylindrical shape whose diameter is larger than that of the connection portion 25.

[0025] A proximal end opening of the passage 21 formed inside the base member 20 on a connection portion 25 side is formed as an inlet 21a for the gas G flowing into the passage 21 via the gas discharge tube 4. Further, a distal end opening of the passage 21 on an insertion portion 27 side is formed as the outlet 21b for the gas G flowing out of the passage 21. [0026] Further, as shown in FIGS. 7 to 9, an annular protrusion shaped seal pressing portion 29 protrudes from an outer periphery slightly closer to the proximal end side with respect to a most distal end of the insertion portion 27. The seal pressing portion 29 is a portion that comes into contact with one end surface of the seal member 70 in a thickness direction and restricts movement of the seal member 70 to the base member 20 in the axial direction.

[0027] Further, as show-n in FIGS. 8 and 9, the base member 20 is provided with a seal member attaching portion 31 to which the seal member 70 is attached, a restricting wall 35 which is disposed on an outer periphery of the seal member 70 and restricts expansion of the seal member 70, and an engaged portion 33 with which a claw portion 61 of the cap member 50 is engaged. The restricting wall 35 is disposed outside the seal member attaching portion 31 and on the outer periphery of the seal member 70.

[0028] In the case of this embodiment, a portion of the insertion portion 27 on the distal end side in the axial direction with respect to the seal pressing portion 29 is formed as the seal member attaching portion 31, and the seal member 70 is mounted on an outer periphery of the seal member attaching portion 31. An outer diameter of the seal member attaching portion 31 is substantially adapted to an inner diameter of the seal member 70.

[0029] Further, the engaged portion 33 with which the claw portion 61 of the cap member 50 is engaged is provided on an outer peripheral edge portion of a surface side (a surface of the base member 20 on an insertion direction Ft side) of the seal pressing portion 29 having the annular protrusion shape. In the case of this embodiment, the engaged portions 33 are respectively provided at positions facing each other in a radial direction of the seal pressing portion 29 (see FIG. 5). As shown in FIG. 9 and a partially enlarged view of FIG. 8, the engaged portions 33 each has a horizontal surface 33a (a surface orthogonal to an axis of the base member 20) formed in a flat horizontal surface shape and a curved surface 33b located radially outward of the horizontal surface 33a and formed in a curved surface shape.

[0030] Further, the restricting wall 35, which is disposed outside the seal member attaching portion 31 and on the outer periphery of the seal member 70 and restricts the expansion of the seal member 70, has the following configuration.

[0031] As shown in FIGS. 1 and 5, in the case of this embodiment, a pair of restriction walls 35, 35 each extending so as to form a curved surface shape along a circumferential direction of the seal pressing portion 29 are disposed with the pair of engaged portions 33, 33 interposed therebetween. Further, as shown in FIGS. 3 and 7, each restricting wall 35 extends toward a distal end of the base member 20 in the extending direction, is provided to have a length reaching a position slightly closer to a front side than a most distal end, and overlaps (1 ap s) with the axial direction of the seal member attaching portion 31 by a predetermined length. In other words, it can be said that a distal end of the seal member attaching portion 31 in the extending direction protrudes from a distal end of the restricting wall 35. Further, an axial length (extending length) of each restricting wall 35 is a length that can cover an entire region of the seal member 70 in the thickness direction (see FIG. 7).

[0032] Further, as shown in FIGS. 5 and 6, when the base member 20 is viewed in the axial direction (when viewed in the extending direction of the base member 20), each restricting wall 35 is an arc-shaped wall formed to have an inner diameter larger than an outer diameter of the seal member 70. The seal member 70 is disposed between the pair of restricting walls 35, 35 and the seal member attaching portion 31 disposed on a radially inner side of the restricting walls 35, 35 (see FIGS. 6 and 7). That is, the pair of restricting walls 35, 35 are disposed on the further outer periphery of the seal member 70 attached on the outer periphery of the seal member attaching portion 31, and the pair of restricting walls 35, 35 restrict the seal member 70 from expanding radially outward.

[0033] The configuration of the restricting wall 35 can also be rephrased as follows. That is, as shown in FIG. 5, it can be said that a pair of cutout portions 39, 39 are respectively formed at two positions, which are radially facing each other, of an annular wall concentrically disposed on the outer periphery of the seal member attaching portion 31, and the annular wall is separated via the pair of cutout portions 39, 39 to provide the pair of restricting walls 35, 35. The engaged portion 33 is disposed at a position aligned with the cutout portion 39.

[0034] Further, as shown in FIGS. 1 and 3, a pair of ribs 37, 37 which each has a thin plate shape and are disposed in parallel to each other, are provided to extend along the extending direction of the base member 20 from a surface (the surface of the base member 20 on the insertion direction Fl side) side of circumferential end edge portions (portions aligned with the engaged portions 33) of the pair of restricting walls 35, 35. One end of each rib 37 in the extending direction is connected to a back side of the flange portion 23 [0035] A cutout portion 40 is formed between the pair of ribs 37, 37. As shown in FIG. 3, the cutout portion 40 is aligned with the cutout portion 39 formed between the pair of restriction walls 35, 35 in the circumferential direction of the base member 20, and as a result, the cutout portions 39, 40 are continuously provided along the axial direction of the base member 20. The cutout portions 39, 40 are disposed to face each other in a radial direction of the base member 20.

[0036] As described above, in this embodiment, the outer periphery of the base member 20 is provided with the cutout portions 39, 40 formed by cutting out a part of the outer periphery, and as shown in FIG. 2, when the cap member 50 is attached to the base member 20, an elastic piece 59 of the cap member 50 enter the cutout portions 39, 40.

[0037] Further, as shown in FIGS. 1, 3, and 5, a pair of fixing pieces 41, 41, which are capable of being deflected and deformed, extend obliquely outward to the flange portion 23 from centers of respective outer peripheries of the pair of restricting walls 35, 35 in the circumferential direction. As shown in FIG. 5, the pair of fixing pieces 41, 41 are disposed orthogonal to the pair of engaged portions 33, 33 and the pair of cutout portions 39, 39. An engagement surface 41a formed in a tapered surface shape is formed on an outer surface of a distal end portion of each fixing piece 41 in the extending direction. As shown in FIG. 7, the engagement surface 41a of each fixing piece 41 is engaged with a peripheral edge on the back side of the attachment hole 7a of the attached member 7, so that the base member 20 is fixed to the attachment hole 7a via the pair of fixing pieces 41, 41, and thus the entire discharge device 10 is attached to the attached member 7.

[0038] Further, as shown in FIG. 8, the base member 20 is provided with a protrusion 43 that is formed at a position facing a guide surface 58 of the cap member 50, serves as a guide when the cap member 50 is to be attached, and suppresses the seal member 70 from coming off. Further, the protrusion 43 protrudes outward from the base member 20, is located inside the cap member 50, and restricts movement of the cap member 50 in the radial direction. [0039] The protrusion 43 in the present embodiment is formed of a pair of protrusions provided on an outer periphery of the most distal end portion of the seal member attaching portion 31 so as to protrude from positions aligned with the cutout portions 39, 40 and the engaged portion 33, and disposed at two positions facing each other in the radial direction of the base member 20 (see FIGS. 3 and 5).

[0040] As shown in FIG. 9 and the partially enlarged view of FIG. 8, each protrusion 43 has a top portion 43a which protrudes most outward in the radial direction from an outer surface of the seal member attaching portion 31, a tapered surface 43b which is formed on an outer surface of the distal end side of the base member 20 and has an inclined surface shape in which a protrusion amount gradually decreases from the top portion 43a toward the distal end of the base member, and an engagement surface 43c which is formed on an outer surface on a side opposite to the tapered surface 43b (the proximal end side of the base member 20) and has an inclined surface shape in which the protrusion amount gradually decreases from the top portion 43a toward the proximal end of the base member.

[0041] As shown in FIGS. 7 and 8, when the cap member 50 is attached to the base member 20, each protrusion 43 is disposed inside a peripheral wall 53 of the cap member 50 and is disposed to face an inner peripheral surface of the peripheral wall 53, and the engagement surface 43c is engaged with an inner peripheral edge portion of the other end of the seal member 70 in the thickness direction. As a result, one end surface of the seal member 70 in the thickness direction is abutted and supported by the seal pressing portion 29, and the other end surface of the seal member 70 in the thickness direction is engaged and supported by the engagement surface 43c of the protrusion 43, and thus the seal member 70 is suppressed from coming oft so as to not move to base member 20 in the axial direction.

[0042] In addition, in the state where the cap member 50 is attached to the base member 20, the protrusion 43 is disposed inside the peripheral wall 53 of the cap member 50, and thus, even when the cap member 50 attempts to radially move with respect to the base member 20, the movement in the radial direction is restricted. In this embodiment, as shown in FIG. 7 and the partially enlarged view of FIG. 8, when the cap member 50 is attached to the base member 20 via the elastic piece 59 and the claw portion 61, a predetermined gap CL is formed between the top portion 43a of the proti-usion 43 and the inner peripheral surface of the peripheral wall 53 of the cap member 50, so that the protrusion 43 is restricted from coming into contact with an inner periphery of the peripheral wall 53 of the cap member 50.

[0043] In addition, since the engagement surface 43c is formed in the inclined surface shape, it is possible to cope with a thickness variation of the seal member 70. Further, when the seal member 70 is attached to the base member 20, the tapered surface 43b makes it difficult for the protrusion 43 to come into contact with the peripheral wall 53 (see FIGS. 8 and 9) of the cap member 50.

[0044] Next, a detailed configuration of the cap member 50 detachably attached to the base member 20 will be described with reference to FIGS. 1 and 7 to 9.

[0045] The cap member 50 of this embodiment includes a lid portion 51 disposed to face the outlet 21b of the passage 21 of the base member 20, and the claw portion 61 to be engaged with the base member 20, and is configured such that when the gas pressure at the gas discharge port 6 is equal to or higher than the predetermined value, the engagement of the claw portion 61 with the base member 20 is released by a pressure received by the lid portion 51, and the claw portion 61 is detached from the base member 20. The cap member 50 has the elastic piece 59, which are capable of being deflected and deformed, extending from an outer periphery of the lid portion 51, and the claw portion 61 protrudes from an inner periphery of the elastic piece 59.

[0046] The cap member 50 is attached to the base member 20 by pushing the cap member 50 toward an outlet 2 lb side of the passage 21 of the base member 20 and engaging the claw portion 61 of the elastic piece 59 with the engaged portion 33 of the base member 20, and a pushing direction of the cap member 50 with respect to the base member 20 at this time is referred to as "Fr (see FIGS. 7 and 8).

[0047] As shown in FIG. 1, the lid portion 51 of the cap member 50 in this embodiment is formed in a substantially circular plate shape, and serves as a portion that receives the gas G flowing out from the outlet 21b of the passage 21 of the base member 20 (It can also be referred to as a portion to which a pressure of the gas G is applied at the gas discharge port 6).

[0048] The peripheral wall 53 formed in a substantially cylindrical wall shape is erected from an outer peripheral edge portion of the lid portion 51. The peripheral wall 53 includes a base portion 55 provided on a proximal end portion (end portion close to the lid portion 51) side in an erecting direction, and a pressing wall portion 57 protruding, in an axial direction of the peripheral wall 53, from an inner peripheral edge portion of a distal end surface 55a of the base portion 55 in the erecting direction and having an outer diameter smaller than that of the base portion 55. The pressing wall portion 57 presses the seal member 70 from the axial direction when the cap member 50 is attached to the base member 20 (see FIGS. 7 and 8).

The base portion 55 and the pressing wall portion 57 have the same inner diameter.

[0049] As shown in FIG. 7, an outer diameter of the base portion 55 has a dimension that substantially corresponds to an outer diameter of the restricting wall 35 of the base member 20 (here, the outer diameter of the base portion 55 is slightly smaller than the outer diameter of the restricting wall 35). Therefore, in the state where the cap member 50 is attached to the base member 20, a distal end surface of the restricting wall 35 of the base member 20 is disposed to face the distal end surface 55a of the base portion 55.

[0050] The outer diameter of the pressing wall portion 57 is formed to be smaller than the inner diameter of the restricting wall 35, and the inner diameter of the pressing wall portion 57 is formed to be larger than the outer diameter of the seal member attaching portion 31 (see FIG. 7). Therefore, when the cap member 50 is attached to the base member 20, the pressing wall portion 57 enters a gap between the seal member attaching portion 31 of the base member 20 and the pair of restricting walls 35, 35, and presses the seal member 70 disposed in the gap from the axial direction to compress and deform the seal member 70 (see FIGS. 7 and 8). As a result, the seal member 70 is deformed so as to expand radially outward.

[0051] Further, a pair of elastic pieces 59, 59 respectively extend from outer peripheral edge portions, which are portions face each other in the radial direction, of the base portion 55 constituting the peripheral wall 53. Each of the elastic pieces 59 has a proximal end portion (fixed end portion) connected to an outer peripheral edge portion of the distal end surface 55a of the base portion 55, extends beyond a distal end of the pressing wall portion 57 of the peripheral wall 53, and is a band-shaped piece having a length (length so as to be lapped) so as to overlap with the engaged portion 33 when the elastic piece 59 is attached to the base member 20, so that the distal end portion of the elastic piece 59 in the extending direction is a free end portion, and is capable of being deflected and deformed inward or outward with respect to the cap member 50. The pair of elastic pieces 59, 59 extend parallel to each other and parallel to the axial direction of the peripheral wall 53 of the cap member 50. A width of the elastic piece 59 in the circumferential direction is narrower than that of the cutout portions 39, 40 of the base member 20, and the elastic piece 59 can enter the cutout portions 39, 40 when the cap member 50 is attached to the base member 20.

[0052] Further, the claw portion 61 is provided so as to protrude from an inner periphery of the distal end portion of the elastic piece 59 in the extending direction. As shown in FIG. 9 and the partially enlarged view of FIG. 8, the claw portion 61 has a top portion 63 which protrudes most from an inner peripheral surface of the elastic piece 59, a tapered surface 65 which is formed on an outer surface on a pushing direction F2 side (side away from the lid portion 51) of the cap member 50 toward the base member 20 and has an inclined surface shape in which a protrusion amount gradually decreases from the top portion 63 toward a distal end side of the elastic piece 59 in the extending direction, and an engagement surface 67 which is formed on an outer surface on a side opposite to the tapered surface 65 (side opposite to the pushing direction F2 of the cap member 50) and has an inclined surface shape in which the protrusion amount gradually decreases from the top portion 63 toward a proximal end side of the elastic piece 59 in the extending direction. The claw portion 61 is formed over an entire range of the elastic piece 59 in the circumferential direction (width direction) (see FIG. 1).

[0053] Then, in order to attach the cap member 50 to the base member 20, the cap member 50 is pushed into the base member 20. Then, the tapered surface 65 of the claw portion 61 is pressed against a distal end surface side, which is opposite to the engaged portion 33, of the seal pressing portion 29 of the base member 20, and the elastic piece 59 is pressed and expanded to be deflected and deformed outward of the cap member 50 (it can be said that the elastic piece 59 is deformed in a direction away from the outer periphery of the base member 20). Thereafter, when the top portion 63 of the claw portion 61 climbs over the engaged portion 33 of the base member 20, the elastic piece 59 is elastically restored to be deflected and deformed inward of the cap member 50 (it can be said that the elastic piece 59 is deformed in a direction approaching the outer periphery of the base member 20), and the engagement surface 67 of the claw portion 61 is engaged with the horizontal surface 33a and the curved surface 33b of the engaged portion 33 (see the partially enlarged view of FIG. 8). As a result, the cap member 50 is attached to the base member 20 via the pair of elastic pieces 59, 59 and the claw portions 61, 61 thereof In this state, as shown in the partially enlarged view of FIG. 8, the engaged portion 33 of the base member 20 and the claw portion 61 of the cap member 50 are disposed on a diagonal line.

[0054] In the present embodiment, the engagement surface 67 having the inclined surface In shape is provided in the claw portion 61, and the claw portion 61 is engaged with the engaged portion 33 including the curved surface 33b of the base member 20, so that an engagement force of the cap member 50 to the base member 20 is lower than that in a case where the engagement surface of the claw portion and the engaged portion are both horizontal surfaces and are engaged with each other. Therefore, when the gas pressure at the gas discharge port 6 becomes equal to or higher than the predetermined value and the pressure of the gas G flowing into the passage 21 from the inlet 21a of the base member 20 and flowing out from the outlet 21b also becomes equal to or higher than a predetermined value, the pair of elastic pieces 59, 59 are respectively deflected and deformed outward via the lid portion 51 of the cap member 50 pressed by the gas G (refer to a two-dot chain line in the partially enlarged view of FIG. 8), the engagement of the claw portion 61 with the engaged portion 33 of the base member 20 is released, and the cap member 50 is detached from the base member 20. [0055] As described above, when the top portion 63 of the claw portion 61 climbs over the engaged portion 33 and is elastically restored, the elastic piece 59 in this embodiment does not completely return to a state (see FIG. 9) of not being deflected and deformed outward of the cap member 50, and the claw portion 61 is engaged with the engaged portion 33 while maintaining a state where the elastic piece 59 is slightly deflected and deformed outward of the cap member 50.

[0056] As shown in the partially enlarged view of FIG. 8, an inclination angle 0 of the engagement surface 67 of the claw portion 61 with respect to the pushing direction F2 of the cap member 50 toward the base member 20 (here, the direction along the axial direction of the peripheral wall 53 of the cap member 50) is preferably 60° to 85°, and more preferably 75° to 80°.

[0057] (Modifications) In the embodiments described above, a shape, configuration, layout, and the like of each of the power storage device, the case, the gas discharge tube, the tube holding member, the gas discharge port, and the like are not limited to the above embodiment. For example, in this embodiment, two power storage devices 1 form one set, and three or more power storage devices may be adopted, and these power storage devices may be used as one set via a connector or a tube. Further, although the gas discharge port 6 is a downward opening, the gas discharge port 6 may be a lateral opening.

[0058] Further, the shapes and configurations of the base member, the cap member, the seal member, the seal washer, and the like constituting the gas discharge device for the power storage device are not limited to the above embodiment.

[0059] For example, although the base member 20 has the connection portion 25 and the insertion portion 27 and is formed in a substantially cylindrical shape as a whole, the base member 20 may have, for example, a substantially rectangular cylindrical shape or a substantially elliptical cylindrical shape, and may have a shape fixed to the gas discharge port and having a passage communicating with the gas discharge port inside the base member. Further, although the base member 20 according to this present embodiment is fixed by inserting the connecting portion 25 of the base member 20 into the gas discharge port 6 of the gas discharge tube 4, the base member may be fixed to the gas discharge port of the tube by inserting the tube into the base member.

[0060] In addition, in the base member 20 according to the present embodiment, two engaged portions 33, two restricting walls 35, and two fixing pieces 41 are provided (provided as one pair), but the number of the engaged portions 33, the number of the restricting walls 35, and the number of the fixing pieces 41 may be one, or three or more.

[0061] Further, in this embodiment, the engaged portion 33 is provided at a part (position aligned with the cutout portion 39) of the surface side of the seal pressing portion 29 formed in the annular protrusion shape, but for example, a recessed portion into which the claw portion can be fitted may be provided on the outer peripheral surface of the base member, and an inner surface of the recessed portion may be used as the engaged portion.

[0062] Further, although the base member 20 according to the present embodiment has the pair of restricting walls 35, 35 each having an arc shape, for example, the restricting wall may be a continuous annular frame-shaped wall (wall having an annular shape, a square annular shape, an elliptical annular shape, or the like) having no separated portion, or may be a plurality of narrow walls (a plurality of separately-disposed walls) disposed at predetermined intervals along the outer periphery of the seal member, and may have a shape or a structure so as to be disposed on the outer periphery of the seal member and capable of restricting the expansion of the seal member.

[0063] Further, although the base member 20 of this embodiment has the pair of fixing pieces 41, 41 each formed in an anchor leg shape, for example, an engagement protrusion may be provided on the outer periphery of the base member, and the engagement protrusion may be engaged with the attachment hole of the attached member, and the attachment structure of the base member to the attachment hole is not particularly limited.

[0064] Further, in the cap member 50 according to this embodiment, although the lid portion Si also has a substantially circular plate shape corresponding to the substantially cylindrical insertion portion 27 of the base member 20, for example, the lid portion may have a substantially rectangular plate shape, a substantially elliptical plate shape, or the like, and may have any shape as long as the lid portion can cover the outlet of the passage of the base member and receive the gas flowing out from the outlet.

[0065] Further, in this embodiment, although the pair of elastic pieces 59, 59 are provided corresponding to the pair of engaged portions 33, 33 of the base member 20, the number of the elastic pieces may be one or three or more as long as the cap member can be attached to the base member.

[0066] In this embodiment, although the claw portion 61 is provided so as to protrude from the inner periphery of the distal end portion of the elastic piece 59, the claw portion may be provided in the middle of the elastic piece in the extending direction as long as the claw portion can be engaged with the engaged portion.

[0067] Further, in this embodiment, the claw portion 61 of the elastic piece 59 is engaged with the engaged portion 33 in the state where the elastic piece 59 is deflected and deformed outward (see the partially enlarged view of FIG. 8), but the claw portion may be engaged with the engaged portion in a state where the elastic piece is not deflected and deformed outward. [0068] Further, in this embodiment, the cap member 50 is configured such that the elastic piece 59 is deflected and deformed outward to be detached from the base member 20 when the gas pressure is equal to or higher than the predetermined value, and in such configuration for the above, the inclination angle of the engagement surface 67 of the claw portion 61 on a cap member 50 side is set to the angle as described in the above paragraph 0056, and the horizontal surface 33a and the curved surface 33b are provided on the engaged portion 33 on a base member 20 side. But the configuration for detaching the cap member from the base member when the gas pressure is equal to or higher than the predetermined value is not limited to the above aspect.

[0069] The configuration for detaching the cap member from the base member may be as follows. For example, (1) the engagement surface of the claw portion of the cap member may be a curved surface, and the engaged portion of the base member may have only a horizontal surface, or a combination of a horizontal surface and a curved surface, or a combination of a horizontal surface and an inclined surface, (2) the engagement surface of the claw portion of the cap member may be an inclined surface, and meanwhile the engaged portion of the base member may have only a horizontal surface or a combination of a horizontal surface and an inclined surface, (3) the engagement surface of the claw portion of the cap member may be a horizontal surface, and meanwhile the engaged portion of the base member may have a combination of a horizontal surface and a curved surface or a combination of a horizontal surface and an inclined surface, (4) the engaged portion of the base member has an inclined surface, and an inclination angle of the inclined surface is adjusted, (5) a combination of (1) to (4) above, and (6) a thickness, width, length, and the like of the claw portion are appropriately set to adjust an engagement margin (engagement area) with respect to the base member.

[0070] Although the seal member 70 and the seal washer 8 both have an annular shape, the seal member 70 and the seal washer 8 may have, for example, a square annular shape, an elliptical annular shape, or the like, and can be appropriately changed according to the shape, the configuration, or the like of the base member.

[0071] Further, although the lid portion 51 of the cap member 50 has a function of receiving the pressure of the gas G, the lid portion may have a pressure regulating function of allowing a gaseous body such as a gas to pass therethrough at a predetermined flow rate without allowing moisture to pass therethrough.

[0072] (Operation Effects) Next, operation effects of the discharge device 10 having the above configurations according to the present invention will be described.

[0073] First, an assembly process of the discharge device 10 will be described.

[0074] That is, the seal member 70 is inserted into the gap between the seal member attaching portion 31 of the base member 20 and the pair of restricting walls 35, 35, and the seal member 70 is pushed until the seal member 70 comes into contact with the seal pressing portion 29. Then, one end surface of the seal member 70 in the thickness direction is abutted and supported by the seal pressing portion 29, and the other end surface of the seal member in the thickness direction is engaged and supported by the engagement surface 43c of the protrusion 43, so that the seal member 70 can be suppressed from coming off, so as to not move to base member 20 in the axial direction.

[0075] In the state where the seal member 70 is attached to the base member 20 as described above, as shown in FIG. 1, the pair of elastic pieces 59, 59 of the cap member 50 are respectively aligned with the cutout portions 39, 40 on one side in the radial direction of the base member 20 and on the other side in the radial direction of the base member 20, and then the cap member 50 is pushed onto the base member 20 in the direction indicated by F2 in FIG, 8. Then, the tapered surface 65 of the claw portion 61 is pressed against the distal end surface side of the seal pressing portion 29, and the elastic piece 59 is pressed and expanded to be deflected and deformed outward.

[0076] Thereafter, when the claw portion 61 climbs over the engaged portion 33, the elastic piece 59 is elastically restored to enter the cutout portions 39, 40 of the base member 20, the engagement surface 67 of the claw portion 61 is engaged with the horizontal surface 33a and the curved surface 33b of the engaged portion 33 (see the partially enlarged view of FIG. 8), and as shown in FIG. 8, the cap member 50 can be attached to the base member 20 in a state where the seal member 70 is interposed between the base member 20 and the cap member 50.

At this time, since the distal end surface 55a of the base portion 55 of the cap member 50 and the distal end surface of the restricting wall 35 of the base member 20 are disposed to face each other (see FIG. 7), even when the cap member 50 is excessively pushed with respect to the base member 20, both distal end surfaces come into contact with each other to function as a pushing stopper, and the seal member 70 can be suppressed from being compressed more than necessary and being worn out. As shown in FIG. 7, an outer diameter of the base portion 55 has a dimension that substantially corresponds to an outer diameter of the restricting wall 35 of the base member 20 (here, the outer diameter of the base portion 55 is slightly smaller than the outer diameter of the restricting wall 35). Therefore, in the state where the cap member 50 is attached to the base member 20, the base member 20 is placed above the distal end surface 55a of the base portion 55.

[0077] Thereafter, the seal washer 8 is disposed on the back side of the flange portion 23 of the base member 20, and the insertion portion 27 of the base member 20 is inserted from the opening of the attachment hole 7a of the attached member 7 on the front side. Then, the pair of fixing pieces 41, 41 are pressed by the inner periphery of the attachment hole 7a and are deflected and deformed inward, and when the engagement surface 41a of the fixing piece 41 comes off from the opening of the attachment hole 7a on the back side, the pair of fixing pieces 41, 41 are elastically restored, the engagement surfaces 41a, 41a thereof are engaged with the peripheral edge of the attachment hole 7a on the back side, and the discharge device 10 can be attached in the attachment hole 7a (see FIG. 7). In this state, the seal washer 8 is sandwiched between the flange portion 23 of the base member 20 and the peripheral edge of the attachment hole 7a of the attached member 7 on the front side, thereby ensuring watertightness.

[0078] Then, when the gas G is generated in the power storage device 1 due to a power supply to a drive source or an electrical component by the power storage device 1 or due to an external environment, an internal environment, or the like of the power storage device 1 (for example, when the power storage device such as the lithium ion battery supplies power by driving a motor or the like, the gas is generated by a chemical reaction of an electrolytic solution), the gas G flows through the connector 3 and the gas discharge tube 4 to reach the gas discharge port 6, and when the gas pressure at the gas discharge port 6 becomes equal to or higher than the predetermined value, the cap member 50 is detached from the base member 20.

[0079] That is, the gas G flows into the passage 21 from the inlet 21a of the base member 20, flows through the passage 21, flows out from the outlet 21b, and presses the lid portion 51 of the cap member 50, when the gas pressure at the gas discharge port 6 becomes equal to or higher than the predetermined value, the pressure of the gas G (see FIG. 8) applied to the lid portion 51 of the cap member 50 also becomes equal to or higher than the predetermined value. Then, since the lid portion 51 of the cap member 50 is pressed by the gas G, the engagement surface 67 of the claw portion 61 is pressed against the curved surface 33b of the engaged portion 33, and the elastic piece 59 is deflected and deformed outward of the cap member 50 via the claw portion 61 as shown by the two-dot chain line in the partially enlarged view of FIG. 8. As a result, the engagement surface 67 of the claw portion 61 is detached from the horizontal surface 33a or the curved surface 33b of the engaged portion 33, and the engagement between the engaged portion 33 and the claw portion 61 is released, so that the cap member 50 is detached from the base member 20 as shown in FIG. 9. The pair of elastic pieces 59, 59 of the cap member 50 detached from the base member 20 are completely elastically restored so as to be parallel to the axial direction of the peripheral wall 53 of the cap member 50.

[0080] As described above, in the discharge device 10, when the gas pressure at the gas discharge port 6 of the power storage device 1 becomes equal to or higher than the predetermined value, the lid portion 51 of the cap member 50 receives the gas pressure and is pressed by the gas pressure, the elastic piece 59 is deflected and deformed outward, and the claw portion 61 thereof is detached from the engaged portion 33 of the base member 20, so that the cap member 50 is detached from the base member 20.

[0081] At this time, the gas pressure is also applied to the seal member 70 to expand the seal member 70 in the radial direction (see a lateral arrow in FIG. 7), but the expansion of the seal member 70 is restricted by the pair of restricting walls 35, 35 of the base member 20, and thus, the gas pressure is firmly applied to the lid portion 51 of the cap member 50 while sealing performance between the base member 20 and the cap member 50 is maintained by the seal member 70. That is, since the sealing performance between the base member 20 and the cap member 50 is maintained by the restricting walls 35, the gas G does not escape (is not exhausted) from the gas discharge port 6 via the seal member 70, and the gas pressure of the gas G is reliably applied on the lid portion 51 of the cap member 50 As a result, the cap member 50 can be reliably detached from the base member 20. Since the seal member attaching portion 31 of the base member 20 is located inside the seal member 70, even when the seal member 70 is to be reduced in diameter in the radial direction as a gas pressure is applied on the seal member 70, the reduction in diameter is restricted.

[0082] As described above, in the discharge device 10, the sealing performance between the base member 20 and the cap member 50 can be maintained, and at the time of increasing the gas pressure at the gas discharge port 6, the cap member 50 can be reliably detached from the base member 20, and the gas G can be discharged from the power storage device 1.

[0083] Further, in this embodiment, as shown in the partially enlarged view of FIG. 8, the cap member 50 has the elastic piece 59 extending from the lid portion 51, the claw portion 61 is formed on the elastic piece 59, and the claw portion 61 is formed to engage with the base member 20 in the state where the elastic piece 59 is deflected and deformed outward. [0084] According to the above aspect, the claw portion 61 is firmly engaged with the base member 20 by utilizing an elastic restoring force of the elastic piece 59, and the cap member can be attached to the base member 20 in a stable posture (here, the cap member 50 can be attached to the base member 20 in a posture in which an axis of the base member 20 and an axis of the peripheral wall 53 of the cap member 50 coincide with each other), and the cap member 50 can be more reliably detached from the base member 20 at a predetermined gas pressure [0085] Further, in this embodiment, as shown in FIGS. 7 and 8, the cap member 50 has the pressing wall portion 57 that presses the seal member 70 from the axial direction when the cap member 50 is attached to the base member 20.

[0086] According to the above aspect, when the cap member 50 is attached to the base member 20, the seal member 70 is pressed from the axial direction by the pressing wall portion 57, and thus, the seal member 70 is held in the axial direction of the base member 20, and the cap member 50 can be easily detached from the base member 20 at the predetermined gas pressure (the cap member 50 is easily detached from the base member 20 since the seal member 70 is not in sliding contact with the cap member 50 in the radial direction). [0087] Further, when the cap member 50 is attached to the base member 20, the seal member 70 is pressed by the pressing wall portion 57 of the cap member 50, and the seal member 70 is compressed, and thus, the sealing performance between the base member 20 and the seal member 70 can be improved.

[0088] Further, when the cap member 50 is attached to the base member 20, the seal member 70 is pressed by the pressing wall portion 57 of the cap member 50, and thus, rattling of the seal member 70 with respect to the base member 20 can be suppressed.

[0089] In this embodiment, as shown in FIG. 8, the base member 20 is provided with the protrusion 43 that protrudes outward of the base member 20, is located inside the cap member 50, restricts the movement of the cap member 50 in the radial direction, and holds the seal member 70 so as to suppress the seal member 70 from coming off.

[0090] Further, in this embodiment, as shown in FIG. 8, the cap member 50 has the guide surface 58 disposed on the outer periphery of the base member 20 when the cap member 50 is attached to the base member 20, and the base member 20 is provided with the engaged portion 33 with which the claw portion 61 is to be engaged, and the protrusion 43 that is formed at the position facing the guide surface 58 of the cap member 50, serves as the guide when the cap member 50 is to be attached, and suppresses the seal member 70 from coming off.

[0091] According to the above aspect, since the protrusion 43 suppresses the seal member from coming off in the axial direction of the base member 20, the seal member 70 can be suppressed from falling off from the base member 20. As a result, when the gas pressure is applied to the seal member 70, the seal member 70 is suppressed from being detached from the base member 20, the sealing performance between the base member 20 and the cap member 50 is reliably maintained, so that the gas pressure can be firmly applied to the lid portion 51 of the cap member 50.

[0092] Further, when the cap member 50 is to be attached to the base member 20, the guide surface 58 of the cap member 50 is guided by the protrusion 43 of the base member 20, and thus the cap member 50 can be easily attached to the base member 20, and the cap member 50 can be attached to the base member 20 in the stable posture, so that the cap member 50 can be more reliably detached from the base member 20 at the predetermined gas pressure by reducing a variation in the engagement margin (engagement area) of the claw portion 61 with respect to the base member 20 [0093] Further, in this embodiment, as shown in the partially enlarged view of FIG. 8, when the cap member 50 is attached to the base member 20, the predetermined gap CL is formed between the protrusion 43 and the guide surface 58 of the cap member 50. Therefore, as described above, it is possible to further improve guide performance when the cap member 50 is to be attached to the base member 20 by using the protrusion 43 and the guide surface 58. In addition, since the predetermined gap CL is provided between the protrusion 43 and the guide surface 58 of the cap member 50 at the time of attaching the cap member 50 to the base member 20, when the gas pressure at the gas discharge port 6 becomes equal to or higher than the predetermined value, and when the cap member 50 is to be detached from the base member 20, no frictional resistance is applied between the guide surface 58 of the cap member 50 and the protrusion 43 of the base member 20, and the cap member 50 can be smoothly detached from the base member 20.

[0094] Further, in this embodiment, the base member 20 is provided with the cutout portions 39,40 which are formed by cutting out a part of the outer periphery of the base member 20 and into which the elastic pieces 59 enter, and the protrusions 43 are provided at the positions respectively aligned with the cutout portions 39, 40 (see FIG. 3).

[0095] According to the above aspect, when the cap member 50 is attached to the base member 20, as shown in FIG. 2, the elastic pieces 59 of the cap member 50 enter the cutout portions 39, 40 of the base member 20, and thus, the elastic piece 59 can be suppressed from protruding radially outward, and the gas discharge device 10 can be made compact in the radial direction. Further, when the cap member 50 is attached to the base member 20, the elastic pieces 59 of the cap member 50 enter the cutout portions 39, 40 of the base member 20, so that the cap member 50 can be attached to the base member 20 in a state where rotation of the cap member 50 is restricted. Further, the base member 20 is provided with the cutout portions 39, 40, and thus by using the cutout portions 39, 40, it is possible to easily attach the seal member 70 to the seal member attaching portion 31 of the base member 20. In addition, since the protrusions 43, 43 are provided at the positions of the base member 20 that are aligned with the cutout portions 39, 40, there is no undercut portion when the protrusions 43, 43 are demolded, so that the protrusions 43, 43 are easily molded.

[0096] Further, in this embodiment, when the cap member 50 is attached to the base member 20, as shown in the partially enlarged view of FIG. 8, the engaged portion 33 of the base member 20 and the claw portion 61 of the cap member 50 are disposed on the diagonal line, and thus, from this viewpoint as well, the discharge device 10 can be made compact in the radial direction.

[0097] Further, in this embodiment, a pair of ribs 37, 37 are provided on the outer periphery of the base member 20, and the elastic piece 59 and the claw portion 61 of the cap member 50 are disposed between the ribs 37, 37, and thus, even when an external force from the outside of the base member 20 is applied, the external force is less likely to be applied to the elastic piece 59 and the claw portion 61, and the attachment state of the base member 20 and the cap member 50 can be firmly maintained [0098] The present invention is not limited to the embodiment described above, and various modified embodiments can be made within the scope of the gist of the present invention, and such embodiments are also included in the scope of the present invention.

REFERENCE SIGNS LIST

[0099] 1 Power storage device 6 Gas discharge port 8 Seal washer Gas discharge device for a power storage device (Discharge device) Base member 21 Passage 21b Outlet 33 Engaged portion Restricting wall 39, 40 Cutout portion 41 Fixing piece 43 Protrusion Cap member 51 Lid portion 53 Peripheral wall 57 Pressing wall portion 59 Elastic piece 61 Claw portion Seal member 20 25 30

Claims (5)

1. CLAIMS1. A gas discharge device for a power storage device that is configured to discharge a gas when a gas pressure at a gas discharge port of the power storage device is equal to or higher than a predetermined value, the gas discharge device comprising: a base member configured to be fixed to the gas discharge port and having a passage configured to communicate with the gas discharge port inside the base member; a cap member to be detachably attached to the base member so as to close an outlet of the passage of the base member; and a seal member disposed between the base member and the cap member, and configured to seal a gap between the base member and the cap member, wherein the cap member includes: a lid portion disposed to face the outlet of the passage of the base member, and a claw portion to be engaged with the base member, the cap member is configured such that when the gas pressure at the gas discharge port is equal to or higher than the predetermined value, engagement of the claw portion with the base member is released by a pressure received by the lid portion, and the cap member is detached from the base member, and the base member is provided with a seal member attaching portion to which the seal member is to be attached, and a restricting wall that is disposed on an outer periphery of the seal member and that is configured to restrict expansion of the seal member.
2. 2. The gas discharge device for the power storage device according to claim 1, wherein the cap member has an elastic piece extending from the lid portion, the claw portion is formed on the elastic piece, and the claw portion is configured to engage with the base member in a state where the elastic piece is deflected and deformed outward.
3. 3. The gas discharge device for the power storage device according to claim 1 or 2, wherein the cap member has a pressing wall portion that is configured to press the seal member from an axial direction when the cap member is attached to the base member.
4. The gas discharge device for the power storage device according to claims 1 to 3, wherein the cap member has a guide surface that is to be disposed on an outer periphery of the base member when the cap member is attached to the base member, and the base member is provided with an engaged portion with which the claw portion is to be engaged, and a protrusion that is formed at a position to face the guide surface of the cap member, that is configured to serve as a guide when the cap member is to be attached, and that is configured to suppress the seal member from coming off.
5. 5. The gas discharge device for the power storage device according to claim 4, wherein the cap member has an elastic piece extending from the lid portion, the claw portion is formed on the elastic piece, the base member is provided with a cutout portion formed by cutting out a part of the outer periphery of the base member and into which the elastic piece is configured to enter, and the protrusion is provided at a position aligned with the cutout portion.