JP2017033886A - Pressure release mechanism of battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress intrusion of air from the outside, by holding a positive pressure in a pack case 2 after gas is discharged.SOLUTION: A pressure release mechanism 11 of a pack case 2 is constituted of a plurality of pressure release holes 12 bored in a wall 5A, a rod-like valve support member 13 placed along the inner side of the wall 5A, and a frustoconical sealing valve 14 supported by the valve support member 13 and press-fitted in the pressure release hole 12 from the inside of the pack case 2. The valve support member 13 has the opposite ends coupled to the wall 5A by means of a bracket 16. When the pressure in the pack case 2 rises, the wall 5A of the pack case 2 is deformed arcuately and the sealing valve 14 is separated from the pressure release hole 12 thus releasing the pressure release hole 12. When the gas is discharged substantially, the pressure release hole 12 is closed along with the shape restoration of the pack case 2, and the internal pressure is held at a positive pressure.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a pressure release mechanism for a battery pack in which a plurality of batteries are accommodated in a pack case, and more particularly to a pressure release mechanism for a relatively large capacity battery pack that serves as a power source for an electric vehicle.

  For example, a battery pack used in an electric vehicle is configured in a state in which a pack case is substantially sealed in order to prevent rainwater, dust, and the like from entering the inside. In other words, in order to avoid pressure change in the pack case due to charge / discharge and temperature change, the inside and outside of the pack case are slightly communicated via a so-called breathing hole that allows a relatively small amount of air to enter and exit. Basically, the pack case is in a sealed state.

  On the other hand, when a large amount of gas is suddenly generated inside the battery pack due to an internal short circuit of the battery, it is necessary to quickly release the internal pressure of the battery pack. Patent Document 1 and Patent Document 2 disclose a kind of explosion-proof valve in which an opening is provided in a part of a battery pack and a lid member covering the opening is removed when gas is generated. Patent Document 1 discloses a configuration in which an opening is opened when a lid member that covers a rectangular opening is broken or deformed or blown away by pressure in the battery pack. Patent Document 2 discloses a configuration in which an opening is opened by forming a lid member with a low melting point material and melting it with the heat of gas generated in a battery pack.

JP 2014-41841 A JP 2014-107178 A

  As described above, the conventional explosion-proof valve type configuration is such that the lid member covering the opening is weaker than the battery pack itself, so that when the gas suddenly occurs inside the battery pack, The opening is opened by breakage, permanent deformation, melting removal, etc., and the opening remains open even after the gas inside the battery pack is almost discharged and the pressure inside the battery pack drops. Become. Therefore, after the pressure inside the battery pack is reduced, external air, that is, oxygen easily flows into the battery pack, and there is a concern that a rapid oxidation reaction of gas occurs inside the battery pack. The third embodiment of Patent Document 2 discloses a configuration including a reed valve-like backflow prevention valve. This backflow prevention valve guides the flow of high-temperature gas to a lid member made of a low melting point material. Since the lid member itself melts when the gas is generated, the opening remains open.

  In addition, in the configurations of Patent Documents 1 and 2, since the lid member that covers a part of the battery pack, that is, the opening portion, is a locally low-strength part, another problem such as the need for countermeasures against stepping stones is new. It is easy to occur.

The battery pack pressure release mechanism according to the present invention is a battery pack in which a plurality of batteries are housed in a substantially sealed pack case.
A pressure release hole formed in the wall of the pack case so as to communicate the internal space and the external space of the pack case;
A valve support member disposed along the inner surface of the wall and having both longitudinal ends connected to the wall;
A sealing valve supported by the valve support member and fitted into the pressure release hole from the inside of the pack case;
It is configured with.

  The pressure release mechanism of the present invention basically achieves release of pressure through the pressure release hole by utilizing elastic deformation of the pack case itself due to an increase in pressure inside the pack case during gas generation. That is, when the pressure inside the pack case increases with the generation of gas, the pack case tends to expand, so that the wall of the pack case in the vicinity of the valve support member is curved and deformed. On the other hand, since the valve support member that supports the sealing valve is connected to the wall at both ends, the deformation following the pack case does not occur. For this reason, the intermediate portion of the valve support member moves away from the wall of the pack case with the curved deformation of the pack case. Therefore, the sealing valve fitted to the pressure release hole from the inside of the pack case is separated from the pressure release hole, and the pressure release hole is opened. Thereby, the pressure inside the pack case is released (in other words, gas is discharged).

  When the gas in the pack case is almost exhausted and the pressure in the pack case decreases, the swelled pack case tries to return to the initial shape again, and the curved deformation of the pack case wall near the valve support member is reduced. Therefore, the sealing valve substantially closes the pressure release hole. Ideally, the pressure is released within the range of elastic deformation of the pack case, and the sealing valve closes the pressure release hole as the pressure drops.

  Therefore, after the gas inside the pack case is almost exhausted, the pack case returns to the substantially sealed state again, and the inside is kept at a slight positive pressure, so that the inflow of air, that is, oxygen from the outside. Is suppressed.

  According to the present invention, by utilizing the deformation of the wall of the pack case according to the pressure inside the pack case, it is possible to quickly release the internal pressure at the time of gas generation and to suppress the subsequent inflow of oxygen. In addition, since the sealing valve itself covering the pressure release hole does not need a function such as breakage due to pressure, it is possible to maintain the same strength as the other parts of the pack case against the stepping stones.

The external appearance perspective view of the battery pack of one Example provided with the pressure release mechanism which concerns on this invention. The perspective view which removed the pack case upper and showed the structure inside a battery pack. The top view of the principal part of the pack case upper which shows one Example of a pressure release mechanism. Sectional drawing of the principal part along the AA line of FIG. Sectional drawing of the principal part along the BB line of FIG. Sectional explanatory drawing of the principal part along the AA line of FIG. 3 when a pack case swells with the internal pressure. Sectional drawing of the principal part along the AA of FIG. 3 which shows the other example of the connection structure of the edge part of a valve support member. FIG. 4A is a cross-sectional view of the main part along the line AA in FIG. 3 and FIG. 3B is a cross-sectional view of the main part along the line BB in FIG. (A) Top view which shows 2nd Example of a valve support member and a sealing valve, (b) Sectional drawing along CC line, (c) Sectional drawing along DD line. (A) Top view which shows 3rd Example of a valve support member and a sealing valve, (b) Sectional drawing along CC line, (c) Sectional drawing along DD line. (A) Top view which shows 4th Example of a valve support member and a sealing valve, (b) Sectional drawing along CC line, (c) Sectional drawing along DD line. (A) Top view which shows 5th Example of a valve support member and a sealing valve, (b) Sectional drawing along CC line, (c) Sectional drawing along DD line. Sectional drawing of the principal part which shows the Example which provided the coating film on the surface of the sealing valve.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view showing an embodiment in which the present invention is applied to, for example, a battery pack 1 for an electric vehicle. The battery pack 1 is a pack case 2 in which a large number of batteries 3 (see FIG. 2) are accommodated in a pack case 2 having a substantially rectangular box shape, and the pack case 2 is a tray-shaped pack constituting a lower portion. It is comprised from the case lower 4 and the pack case upper 5 which comprises an upper part. The pack case lower 4 and the pack case upper 5 are each formed in a tray shape by press-forming steel plates having appropriate thicknesses, joined to each other at the peripheral edge, and joined to each other by a bolt or the like (not shown). . The joint surface between the two is sealed with an appropriate sealing material such as a liquid gasket, so that the inside of the pack case 2 is substantially sealed so as to prevent intrusion of rainwater, dust and the like from the outside. It has become. In order to avoid a pressure change in the pack case 2 due to charging / discharging or temperature change, a relatively small amount of air is allowed to enter and exit through a breathing hole (not shown), for example.

  FIG. 2 shows the internal configuration of the battery pack 1 with the pack case upper 5 removed. In this embodiment, each battery 3 is a battery module in which a plurality of (for example, four) flat lithium ion cells sealed with a laminate film as an exterior body are stacked and accommodated in a box-shaped metal case. It is configured as. A plurality of batteries 3 having a flat rectangular parallelepiped shape are arranged in a so-called vertical arrangement at one end of the pack case 2 in the longitudinal direction (Y direction in the figure). In the area, they are arranged side by side in a so-called flat stacked form. A cooling fan 6, a junction box 7, and the like are disposed at the other end in the longitudinal direction of the pack case 2.

  As apparent from FIG. 2, in the region where the battery 3 is placed vertically, the size in the vertical direction (Z direction in the drawing) is larger than the region where the batteries 3 are arranged in a flat stack. As shown in FIG. 1, the ceiling surface of the pack case upper 5 is formed in a shape corresponding to the unevenness of the arrangement of the battery 3, that is, the high ceiling portion 5H at one end portion in the longitudinal direction and the remaining portion. And a low ceiling portion 5L.

  The pressure release mechanism 11 of the present invention can be provided at any position of the pack case 2, but in one embodiment, when the internal pressure rises, the pack case 2 is moved in the front-rear direction (Y direction in the figure). A pressure release mechanism 11 as will be described later is arranged on the high ceiling portion 5H where the curved deformation appears relatively large along the line. The pack case upper 5 is made of a steel plate that is thinner than the pack case lower 4. Therefore, when the internal pressure rises, the pack case upper 5 is relatively positioned relative to the pack case lower 4. Deforms greatly.

  3 and 4 show an embodiment of the pressure release mechanism 11. The pressure release mechanism 11 has a plurality of pressure release holes 12 formed in the wall 5A of the pack case upper 5 in the high ceiling portion 5H, and a bar having a rectangular cross section disposed along the inner surface of the wall 5A. The valve support member 13 includes a plurality of sealing valves 14 that are supported by the valve support member 13 and seal the pressure release holes 12 from the inside of the pack case 2. In one embodiment, it has a pair of valve support members 13 arranged in parallel, and each of the valve support members 13 has 10 sealing valves 14 arranged in a line along the longitudinal direction thereof. Is arranged. The pressure release holes 12 are provided corresponding to these sealing valves 14, and therefore the pressure release mechanism 11 as a whole has a total of 20 pressure release holes 12 in the form of “10 × 2 rows”. It is arranged. Each pressure release hole 12 has a circular shape with a diameter of about several millimeters, and the opening edge 12a on the inner side surface of the wall 5A is chamfered into a taper shape. In addition, these several pressure release holes 12 are arrange | positioned in the part of the wall 5A which makes a flat surface fundamentally. Further, as shown in FIG. 1, the plurality of pressure release holes 12 and the valve support members 13 are arranged so that the longitudinal direction of the valve support member 13 is along the front-rear direction of the pack case 2 (the Y direction in FIG. 1). Yes.

  The valve support member 13 is preferably made of a rod-shaped steel material having higher bending rigidity than the pack case upper 5, and both end portions 13a in the longitudinal direction are connected to the wall 5A. Specifically, the valve support member 13 is allowed to move slightly along the longitudinal direction of the valve support member 13 through an appropriate connection structure so that the valve support member 13 does not leave the wall 5A in the thickness direction of the wall 5A. The end 13a is connected to the wall 5A. For example, a long hole 15 along the longitudinal direction of the valve support member 13 is formed at the end 13a of the valve support member 13, and a substantially U-shaped bracket 16 passing through the long hole 15 is fixed to the wall 5A. Each end portion 13a is suspended from the wall 5A by the engagement between the bracket 16 and the long hole 15.

  The sealing valve 14 has a truncated cone shape with a diameter corresponding to the pressure release hole 12. In other words, the circumferential surface has a tapered shape with a gradually decreasing diameter from the inside to the outside of the pack case 2, and the pressure release hole 12 having the opening edge 12 a chamfered into a taper shape from the inside of the pack case 2. It can be fitted. In the illustrated example, the sealing valve 14 made of steel is provided integrally with the valve support member 13 and protrudes in a protruding shape from the upper surface of the valve support member 13 (the surface facing the wall 5A). The valve support member 13 and the sealing valve 14 may be integrally formed from a single base material, and the separately formed sealing valve 14 may be formed by screws, rivets, welding, or the like (not shown). You may make it fix to.

  As described above, the plurality of sealing valves 14 supported by the valve support member 13 are press-fitted relatively lightly into the pressure release hole 12 in advance. As the taper angle of the peripheral surface of the sealing valve 14 (inclination angle with respect to the central axis of the truncated cone), the pressure release hole is maintained when each sealing valve 14 is pulled inward while maintaining an appropriate press-fitted state. It is desirable to set it to such an extent that it can escape from 12, and for example, it is set to about 5 ° to 30 °. In other words, the smaller the taper angle, the higher the sealing performance when the sealing valve 14 is fitted in the pressure release hole 12, but on the other hand, when the pressure inside the pack case 2 rises, the pressure release hole 12 It becomes difficult to come off. Therefore, it is desirable to set the taper angle in consideration of both. Note that shrink fitting may be used instead of press fitting.

  In the state in which the sealing valve 14 is fitted in the pressure release hole 12, as shown in FIGS. 4 and 5, the pair of valve support members 13 are located along the inner surface of the wall 5A. A sheet-like filter member 18 made of, for example, a wire mesh is attached to the inner surface of the wall 5A so as to cover the pair of valve support members 13 together with the pressure release holes 12 from the inside of the pack case 2. For example, the filter member 18 is preliminarily formed in a tray shape, and the peripheral edge portion 18a is attached to the inner surface of the wall 5A via an adhesive or the like. This filter member 18 is for preventing the release of solid matter from the inside of the pack case 2 when gas is released. In addition to the above-described wire mesh, the filter member 18 is made of a mesh, wool or the like made of a nonflammable metal or ceramic material. Alternatively, a curl-like one can be used.

  In the pressure release mechanism 11 configured as described above, during normal use, as shown in FIGS. 4 and 5, the sealing valve 14 is lightly pressed into the pressure release hole 12 and fitted into the pressure release hole 12. As a result, the pressure release hole 12 is securely sealed. Therefore, intrusion of dust and rainwater through the pressure release hole 12 is prevented. In addition, there is no risk of damage due to stepping stones.

  On the other hand, when gas is generated due to an internal short circuit of the cell and the pressure in the pack case 2 rises, each part of the pack case 2 receives a force from the inside based on the pressure difference from the atmospheric pressure, and the pack case 2 has a substantially rectangular cross section. Will bend and deform in an attempt to expand outward. That is, the flat wall 5A near the pressure release mechanism 11 is curved and deformed in an arc shape as shown in FIG. At this time, the rod-shaped valve support member 13 does not receive a force due to a pressure difference between the internal pressure and the atmospheric pressure, and tries to maintain a straight state while the both end portions 13 a are supported by the brackets 16. Note that the change in the distance along the longitudinal direction of the valve support member 13 due to the deformation of the wall 5 </ b> A in an arc shape is absorbed by the relative movement of the bracket 16 and the long hole 15. Therefore, with the curved deformation of the wall 5A, the intermediate portion of the valve support member 13 including the sealing valve 14 is relatively separated from the inner wall surface of the wall 5A, and the sealing valve 14 is placed in the pressure release hole 12 as shown in the figure. The pressure release hole 12 is released.

  Thereby, the high-pressure gas inside the pack case 2 is discharged to the outside through the pressure release hole 12. Here, in the above configuration, since the pack case 2 itself receives a pressure difference over a wide area, the wall 5A is deformed with a relatively low pressure difference, and gas discharge can be started with good responsiveness. In addition, each pressure release hole 12 is relatively small, and in the process in which the pack case 2 is deformed relative to the valve support member 13, ten pressure release holes 12 in a row are sequentially opened. Since it becomes a shape, the flow velocity of the gas to be ejected can be suppressed relatively low. In other words, since the pressure release holes 12 are sequentially opened according to the internal pressure, that is, according to the degree of deformation of the pack case 2, the pressure release holes 12 are opened (the first one is opened) when the internal pressure is low. At the same time, when the internal pressure further increases, a large passage area can be obtained by opening the plurality of pressure release holes 12.

  Since the pressure release hole 12 is covered with the filter support 18 from the inside of the pack case 2 together with the valve support member 13, the solid or foreign matter contained in the gas is captured by the filter member 18 and released to the outside. It will not be done.

  The deformation of the pack case 2 is basically performed within the range of elastic deformation. In other words, the opening of the pressure release hole 12 is started within the range of elastic deformation, and the gas is discharged. Therefore, when the gas in the pack case 2 is almost discharged and the pressure is lowered, the wall 5A of the pack case 2 tries to return to the initial shape, and the sealing valve 14 closes the pressure release hole 12 from the inside again. When the sealing valve 14 substantially closes the pressure release hole 12, the inside of the pack case 2 is in a slight positive pressure state. Therefore, the inside of the pack case 2 remains as it is by closing the pressure release hole 12. Very little positive pressure is maintained. Therefore, the inflow of air, that is, oxygen from the outside through the pressure release hole 12 is suppressed. Here, it is not necessary for the sealing valve 14 to return to the initial press-fitted state, and it is sufficient to return the pressure release hole 12 to a substantially closed state.

  In the illustrated example, the ten sealing valves 14 are arranged on the valve support member 13 at equal intervals. However, in consideration of the deformation mode of the wall 5A, the sealing valves 14 are arranged at appropriate unequal intervals. Also good.

  Next, some modifications in which a part of the above embodiment is changed will be described.

  FIG. 7 shows a modified example of the connection structure between the end 13a of the valve support member 13 and the wall 5A. In this example, the valve support member is formed by a bracket 21 in which a belt-like metal plate is bent into a substantially Z shape. 13 end portions 13a are supported from below. That is, the bracket 21 has a guide portion 21a along the lower surface of the valve support member 13, and the valve support member 13 is supported by the guide portion 21a so as to be movable in the longitudinal direction. As described above, the sealing valve 14 on the valve support member 13 is press-fitted into the pressure release hole 12, so that the valve support member 13 is positioned with respect to the wall 5A.

  FIGS. 8A and 8B show still another example of the connection structure between the end 13a of the valve support member 13 and the wall 5A. In this example, a long hole 15 is provided in the end portion 13 a of the valve support member 13 in the same manner as in the embodiment of FIGS. 4 and 5, and both ends of the support shaft 22 passing through the long hole 15 are supported by the bracket 23. Has been.

  FIG. 9 shows a second embodiment of the valve support member and the sealing valve. In this embodiment, the rod-shaped valve support member 113 has a U-shaped cross section composed of a pair of side walls 113a and a top wall 113b, and is sealed in a mounting hole 113c formed through the top wall 113b. A valve 114 is attached. The sealing valve 114 has a frustoconical valve body 114a, a mounting shaft portion 114b penetrating the mounting hole 113c, and a retaining flange portion 114c provided at the end of the mounting shaft portion 114b. It is attached to the hole 113c so as to have a slight play (in other words, a gap) in both the radial direction and the axial direction. Therefore, in this embodiment, when a plurality of (for example, ten) sealing valves 114 arranged on one valve support member 113 are press-fitted into the pressure release holes 12 as described above, each pressure release hole 12 is pressed. And the tolerance in the relative position between the sealing valve 114 and the error can be easily absorbed, and the sealing valve 114 can reliably seal the pressure release hole 12.

  FIG. 10 shows a third embodiment of the valve support member and the sealing valve. In this embodiment, the rod-shaped valve support member 213 is formed in an H-shaped cross section composed of a pair of side walls 213a and a central wall 213b, and is sealed in a mounting hole 213c formed through the central wall 213b. A valve 214 is attached. The sealing valve 214 has a truncated cone-shaped valve body 214a, a mounting shaft portion 214b that penetrates the mounting hole 213c, and a retaining flange portion 214c provided at the end of the mounting shaft portion 214b. It is attached to the hole 213c so as to have a slight play in both the radial direction and the axial direction. Therefore, similar to the embodiment of FIG. 9, the tolerance or error of the relative position with respect to the pressure release hole 12 can be absorbed.

  FIG. 11 shows a fourth embodiment of the valve support member and the sealing valve. In this embodiment, the valve support member 313 having a rod shape is formed in an H-shaped cross section including a pair of side walls 313a and a central wall 313b, and an attachment groove 313c is formed on the upper surface portion. A plurality of sealing valves 314 are attached to 313c. The mounting groove 313c has a substantially C-shaped cross section in which the groove opening width on the upper surface of the valve support member 313 is narrowed by a pair of locking walls 313d, is continuous over the entire length of the valve support member 313, and supports the valve. The member 313 is open at both ends (at least one end). The sealing valve 314 includes a truncated cone-shaped valve body 314a, a mounting shaft portion 314b that passes through a narrow opening of the mounting groove 313c, and a flange that is slidably fitted in the mounting groove 313c along the longitudinal direction. Part 314c, and the flange part 314c is retained in the axial direction by engaging with the locking wall 313d. There is slight play between the flange portion 314c and the locking wall 313d.

  According to this embodiment, as in the embodiments of FIGS. 9 and 10, tolerances or errors in the relative position between the pressure release hole 12 and the sealing valve 314 can be absorbed. In particular, in this embodiment, for example, ten sealing valves 314 are first press-fitted into the pressure release hole 12, and then the valve support member 313 is moved along the wall 5A while the flange portion 314c of each sealing valve 314 is moved. Can be sequentially inserted from the end of the valve support member 313 into the mounting groove 313c. Therefore, the press-fitting work of the sealing valve 314 is facilitated, and the sealing performance of the pressure release hole 12 can be enhanced.

  FIG. 12 shows a fifth embodiment of the valve support member and the sealing valve. In this embodiment, the rod-like valve support member 413 has a flat rectangular cross-sectional shape with a narrow width in the direction along the wall 5A, and the elongated hole 413a formed in the plate thickness direction penetrates the long hole 413a. A sealing valve 414 is attached. The sealing valve 414 includes a truncated cone-shaped valve body 414a, a pair of leg portions 414b extending so as to sandwich the valve support member 413, and a support shaft having both ends supported by the leg portions 414b through the long hole 413a. 414c. In a state where the sealing valve 414 is assembled to the valve support member 413, the sealing valve 414 is movable along the long hole 413a and has a slight play in the axial direction.

  Therefore, as in the embodiments of FIGS. 9 to 11, tolerances or errors in the relative position between the pressure release hole 12 and the sealing valve 414 can be absorbed. In particular, according to this embodiment, after assembling a plurality of sealing valves 414 to the valve support member 413, an attachment method for press-fitting the sealing valve 414 into the pressure release hole 12, and an individual method as in the embodiment of FIG. Both the mounting method of assembling each sealing valve 414 to the valve support member 413 after press-fitting into the sealing valve 414 pressure release hole 12 are possible.

  In addition, when comprising a sealing valve as another member like the Example of FIGS. 9-12, in addition to steel, for example, metals, such as aluminum and copper, or the hard composite which has heat resistance other than steel It can be formed from a resin or the like.

  The same applies to the valve support member, and in addition to the above-described steel, it can also be formed from a metal such as aluminum or copper or a hard synthetic resin having heat resistance. The valve support member does not necessarily have a bending rigidity higher than the bending rigidity of the wall 5 </ b> A, and it is sufficient if the valve supporting member has a rigidity sufficient to realize separation from the pressure release hole 12 of the sealing valve as described above. In order to reliably release the sealing valve from the pressure release hole 12, the valve support member preferably has a bending rigidity higher than that of the wall 5A.

  FIG. 13 shows an embodiment in which after the sealing valve 14 is press-fitted into the pressure release hole 12, a coating film 31 is provided on the surface of the wall 5A by rust prevention coating or exterior coating. By providing the coating film 31 in this way, the sealing performance of the pressure release hole 12 by the sealing valve 14 can be further enhanced, and the intrusion of rainwater and dust can be more reliably suppressed.

DESCRIPTION OF SYMBOLS 2 ... Pack case 5 ... Pack case upper 5A ... Wall 11 ... Pressure release mechanism 12 ... Pressure release hole 13 ... Valve support member 14 ... Sealing valve 16 ... Bracket 18 ... Filter member

Claims (6)

In a battery pack in which a plurality of batteries are accommodated in a substantially sealed pack case,
A pressure release hole formed in the wall of the pack case so as to communicate the internal space and the external space of the pack case;
A valve support member disposed along the inner surface of the wall and having both longitudinal ends connected to the wall;
A sealing valve supported by the valve support member and fitted into the pressure release hole from the inside of the pack case;
A pressure release mechanism for a battery pack comprising:   The pressure release mechanism of the battery pack according to claim 1, wherein the pressure release hole is a circular hole, and the sealing valve has a tapered shape whose diameter decreases from the inside to the outside of the pack case.   A plurality of sealing valves are arranged along a longitudinal direction in one valve support member, and a plurality of pressure release holes are arranged in the wall corresponding to these sealing valves. The pressure release mechanism of the battery pack according to 2.   At least one end of the valve support member is connected to the wall of the pack case so as to allow movement along the longitudinal direction of the valve support member. The pressure release mechanism of the described battery pack.   The pressure release mechanism of the battery pack according to any one of claims 1 to 4, wherein the sealing valve is press-fitted into the pressure release hole.   The pressure release mechanism of the battery pack according to any one of claims 1 to 5, wherein a filter member that covers the valve support member together with the pressure release hole from the inside of the pack case is attached to an inner surface of the wall.

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