Gasket

Abstract

This gasket (1) includes: a plurality of flow path parts (10); and a base body (20) having a front surface (21) and a back surface (22). The base body (20) has elasticity. The flow path parts (10) are held by the base body (20) so as to define flow paths for an object to be sealed and so that openings (11, 12) of each flow path part (10) open in the front surface (21) and the back surface (22), respectively, of the base body (20). The hardness of the base body (20) is lower than the hardness of the flow path parts (10). The base body (20) is configured to be compressed between a battery cell (110) and a discharge pipe (120) until the front surface (21) and the back surface (22) are in contact with the battery cell (110) and the discharge pipe (120), respectively. A part of the contact between the back surface (22) and the battery cell (110) is released when the air pressure in the flow path parts (10) rises.

Description

gasket

[0001] The present invention relates to a gasket.

[0002] A battery module having multiple battery cells, such as a lithium-ion battery module, is provided with a gas release path that guides gas released from an explosion-proof valve provided in each battery cell to the outside. The explosion-proof valve of each battery cell is connected to the gas release path, and gas released from the explosion-proof valve of each battery cell is guided to the outside through the gas release path. In the battery module, when the internal pressure of each battery cell becomes high due to gas generated in the battery cell, the gas is released to the outside through the explosion-proof valve. In addition, a gasket is provided between the explosion-proof valve of each battery cell and the gas release path, and the gasket seals the communication path between the explosion-proof valve and the gas release path, preventing gas released from the explosion-proof valve from leaking outside the gas release path (see, for example, Patent Document 1).

[0003] The gasket of such a battery module must adhere closely to the battery module and the gas release path to seal the gas released from the explosion-proof valve. For this reason, the gasket has a low hardness and low reaction force, and is made of a foam material such as foamed silicone foam or urethane foam. If the gasket has a low hardness, the reaction force generated when the gasket deforms is low, and the gasket can easily conform to the shape of the object it comes into contact with.

[0004] Special Publication No. 2022-500810

[0005] The gas released from the explosion-proof valve is high-pressure. The gas released from the explosion-proof valve is also high-temperature, sometimes reaching temperatures of 400°C or higher. For this reason, conventional gaskets made from foam materials have a foam structure and are prone to deformation, which can lead to leakage of the high-pressure gas released from the explosion-proof valve. Furthermore, conventional gaskets made from foam materials can melt when exposed to the gas released from the explosion-proof valve. Therefore, gaskets for conventional explosion-proof valves are required to have a configuration that is highly conformable to the object they come into contact with and has excellent pressure and heat resistance.

[0006] On the other hand, because high-pressure gas is released from the explosion-proof valve, if the gasket's pressure resistance is increased, the released high-pressure gas may be instantaneously compressed inside the gasket, increasing the pressure even further, which may cause the gasket to deform or break.Furthermore, this deformation or breakage of the gasket may create a gas leakage path in the gasket, which may result in the leakage of more gas than the allowable leakage amount.

[0007] As such, conventional gaskets for explosion-proof valves are required to have a configuration that is highly conformable to the object they come into contact with, has excellent pressure resistance and heat resistance, and yet is not deformed or damaged by the gas released from the explosion-proof valve.

[0008] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide a gasket that has high conformability to the object it comes into contact with, excellent pressure resistance and heat resistance, and can be prevented from being deformed or damaged by gas released from an explosion-proof valve.

[0009] In order to achieve the above object, the gasket of the present invention is a gasket for sealing an object to be sealed between two members, and comprises a flow path portion which is a tubular member having a plurality of pairs of openings, and a base having a pair of surfaces facing each other, the base having elasticity, the flow path portion being held on the base so that the pair of openings are each open from the pair of surfaces of the base to form a flow path for the object to be sealed, the hardness of the base being lower than the hardness of the flow path portion, the base being compressed between the two members, the pair of surfaces being in contact with the two members respectively, and a portion of the contact between one of the pair of surfaces and one of the two members being released when the air pressure in the flow path portion rises.

[0010] In a gasket according to one aspect of the present invention, the contact between the one surface and the one member is formed on the side of an end of the one surface.

[0011] In the gasket according to one aspect of the present invention, when the air pressure reaches or exceeds a predetermined level, a part of the contact between the one surface and the one member is released.

[0012] In one embodiment of the gasket of the present invention, a plurality of grooves are formed on the one surface, recessed toward the other side of the pair of surfaces, and at least one of the grooves is connected to the opening on the one surface side of each of the plurality of flow path portions, the plurality of grooves extend to the end of the one surface, and a portion of the groove is blocked between the two members.

[0013] In a gasket according to one aspect of the present invention, a portion of the groove is arranged between the two members and contacts a portion of one of the members.

[0014] In a gasket according to one aspect of the present invention, a portion of the groove is shallower than another portion of the groove.

[0015] In a gasket according to one aspect of the present invention, the groove becomes shallower from the side of the opening of the flow path portion with which the groove communicates toward the end of the one surface.

[0016] In a gasket according to one aspect of the present invention, the groove becomes continuously shallower from the opening side toward the end.

[0017] In a gasket according to one aspect of the present invention, the groove becomes shallower in stages from the opening side toward the end.

[0018] In a gasket according to one aspect of the present invention, the depth of the groove in a portion of the groove is smaller than the crushing allowance on the one surface side of the base body.

[0019] In the gasket according to one aspect of the present invention, the edge of the one surface forms the contour of the one surface.

[0020] In a gasket according to one aspect of the present invention, the base has a plurality of through holes penetrating the base between the pair of surfaces, and the flow path portion is held in each of the plurality of through holes.

[0021] In a gasket according to one embodiment of the present invention, the base has a plurality of through holes penetrating the base between the pair of surfaces, and the plurality of flow path portions are embedded in the base so that each of the plurality of through holes is accommodated inside the flow path portion.

[0022] In the gasket according to one aspect of the present invention, the pair of openings of the flow path portion are located inside the pair of surfaces of the base, respectively.

[0023] In a gasket according to one aspect of the present invention, the base is formed from a low-hardness material, and the low-hardness material includes rubber, urethane, and elastomer.

[0024] In a gasket according to one aspect of the present invention, the flow path portion is formed of a heat-resistant material, and the heat resistance of the flow path portion is heat resistance against the temperature of the object to be sealed.

[0025] In one aspect of the gasket of the present invention, the material is PTFE.

[0026] In a gasket according to one aspect of the present invention, the base has a recess between two adjacent flow path portions, and the recess is recessed from a pair of surfaces of the base.

[0027] In a gasket according to one embodiment of the present invention, one of the two components is a plurality of battery cells of a battery module, and the other of the two components is a gas release section that forms a space for guiding gas released from the explosion-proof valves of each of the plurality of battery cells, the object to be sealed is the gas released from the plurality of explosion-proof valves, and the plurality of flow path sections each form a flow path for the gas released from the plurality of explosion-proof valves.

[0028] The gasket of the present invention has high conformability to the object it comes into contact with and has excellent pressure resistance and heat resistance, which can prevent deformation or damage due to gas released from the explosion-proof valve.

[0029] 1 is an exploded perspective view schematically showing a battery module in which a gasket according to an embodiment of the present invention is used. FIG. 2 is a plan view of the gasket shown in FIG. 1. FIG. 3 is a rear view of the gasket shown in FIG. 1. FIG. 4 is a cross-sectional view of the gasket showing a cross section along line A-A in FIG. 2. FIG. 5 is an enlarged cross-sectional view showing an enlarged view of the vicinity of a flow path portion of the gasket shown in FIG. 4. FIG. 6 is an enlarged cross-sectional view showing an enlarged view of the vicinity of a groove of the gasket shown in FIG. 5. FIG. 7 is a cross-sectional view of the gasket showing a cross section along line B-B in FIG. 6. FIG. 8 is a partial cross-sectional view of a battery module showing a cross section of the gasket in a used state attached to the battery module. FIG. 9 is a cross-sectional view showing a modified example of the gasket.

[0030] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that in the drawings, not all of the components are labeled with reference numerals, and some of the components may be omitted. A gasket according to the present invention is used in a battery module having multiple battery cells, such as a lithium-ion battery module, to seal in gas released from an explosion-proof valve provided in each battery cell.

[0031] FIG. 1 is an exploded perspective view schematically illustrating a battery module 100 using a gasket 1 according to a first embodiment of the present invention. FIG. 2 is a plan view of the gasket 1, and FIG. 3 is a rear view of the gasket 1. FIG. 4 is a cross-sectional view of the gasket 1 taken along line A-A in FIG. 2. The gasket 1 is a gasket for sealing gas released from the explosion-proof valves 111, which are objects to be sealed, between a plurality of battery cells 110 of the battery module 100 and a discharge pipe 120 serving as a gas release section that forms a space for guiding gas released from the explosion-proof valves 111 of each of the plurality of battery cells 110.

[0032] As shown in FIGS. 1 to 4 , the gasket 1 includes a flow path portion 10, which is a cylindrical member having a plurality of pairs of openings 11 and 12, and a base 20 having a pair of opposing surfaces, a front surface 21 and a back surface 22. The base 20 is elastic. The flow path portion 10 is held by the base 20 so that the openings 11 and 12 are open from the front surface 21 and the back surface 22 of the base 20, respectively, to form a flow path for the sealed object. The hardness of the base 20 is lower than that of the flow path portion 10. The base 20 is compressed between two members (a battery cell 110 and a discharge pipe 120), and the front surface 21 and the back surface 22 are in contact with the battery cell 110 and the discharge pipe 120, respectively. A portion of the contact between the back surface 22, which is one of the pair of surfaces, and the battery cell 110, which is one of the two members, is released when the air pressure inside the flow path portion 10 increases.

[0033] The contact between the rear surface 22 and the battery cell 110 is formed, for example, on the side of an edge 23 of the rear surface 22. Furthermore, for example, when the air pressure in the flow path portion 10 reaches a predetermined level or higher, part of the contact between the rear surface 22 and the battery cell 110 is released. The configuration of the gasket 1 will be specifically described below.

[0034] Specifically, for example, a plurality of grooves 3 are formed on the back surface 22 of the base 20, recessed toward the front surface 21. At least one groove 3 is connected to the opening 12 on the back surface 22 side of each of the plurality of flow path portions 10. The plurality of grooves 3 extend to an end 23 of the back surface 22. A portion of the groove 3 is closed between the two members. The configuration of the gasket 1 will be described in more detail below.

[0035] As shown in FIG. 1 , in a battery module 100, a plurality of battery cells 110 are arranged in a row and fixed by fasteners (not shown). For example, an insulating resin (not shown) is interposed between the battery cells 110. The plurality of battery cells 110 are connected together to form a battery cell group 101. The battery cells 110 are, for example, secondary batteries such as lithium-ion batteries, and are rechargeable. Each battery cell 110 has an external shape that is, for example, rectangular, with a length in the width direction (X direction) longer than the height direction (Z direction) and a thin thickness direction (Y direction). The battery cells 110 are arranged in the Y direction.

[0036] As described above, each battery cell 110 has an explosion-proof valve 111 and a pair of electrodes 112. The explosion-proof valve 111 and the electrodes 112 are provided on the upper surface 110a of the battery cell 110. The pair of electrodes 112 are arranged at both ends in the width direction, one of which serves as a positive electrode and the other as a negative electrode. The explosion-proof valve 111 is arranged in the center in the width direction. In secondary batteries such as lithium-ion batteries, gas may be generated internally due to charging and discharging during use or external factors, causing internal pressure to increase. The explosion-proof valve 111 opens when the internal pressure of the battery cell 110 rises to a certain level, releasing the generated gas. This prevents the internal pressure of the battery cell 110 from rising to an unacceptable level.

[0037] The discharge pipe 120 is an exhaust device that guides gas ejected when the explosion-proof valve 111 is opened. The discharge pipe 120 is fixed to each battery cell 110 via a gasket 1 so as to straddle the battery cells 110 arranged in a row in the Y direction. The gasket 1 is in a compressed state and sandwiched between the discharge pipe 120 and the upper surface 110a of each of the arranged battery cells 110. The discharge pipe 120 has openings 122 (see FIG. 8 , described later) that correspond to the explosion-proof valves 111 of each battery cell 110. In the discharge pipe 120, gas discharge paths 123 (see FIG. 8 , described later) guide the gas that flows in from each opening 122 to the outside. The gas discharge paths 123 are open to the outside space through the exhaust port 121. The gas ejected from each explosion-proof valve 111 passes through the flow path 10 of the gasket 1 and is guided to the discharge pipe 120, passes through the corresponding opening and gas discharge path, and is discharged from the exhaust port 121 to the outside space.

[0038] 1 to 4, the gasket 1 has the same number of flow path portions 10 as the explosion-proof valves 111 of the plurality of battery cells 110 in the battery cell group 101 of the battery module 100, and is arranged corresponding to the explosion-proof valves 111 of the plurality of battery cells 110. The plurality of flow path portions 10 are arranged in a row, for example, at equal or approximately equal intervals.

[0039] As shown in FIGS. 1 to 4 , the flow path unit 10 has a cylindrical shape extending along the axis x and defines a flow path 13 therein, which is a space extending along the axis x. The axis x extends parallel or approximately parallel to the height direction (Z direction) of the battery module 100. The flow path unit 10 has, for example, a cylindrical or approximately cylindrical shape with the axis x as its central axis or approximately central axis. The shape of the flow path unit 10 is not limited to a cylindrical shape. For example, the flow path unit 10 may be a polygonal cylindrical shape. The cross-sectional shape of the flow path unit 10 perpendicular to the axis x is not limited to a circular shape but may be an ellipse, another circular shape, a polygon, or the like. As shown in FIG. 5 , the flow path unit 10 has a pair of end faces in the direction of the axis x, namely, an upper end face 14 and a lower end face 15. The upper end face 14 defines an opening 11, and the lower end face 15 defines an opening 12. The upper end surface 14 and the lower end surface 15 each extend, for example, along a plane perpendicular to the axis x. The flow path 13 extends between the opening 11 and the opening 12.

[0040] The openings 11 and 12 of the flow path portion 10 each have a shape corresponding to the explosion-proof valve 111 of the battery cell 110, for example, a shape capable of accommodating the explosion-proof valve 111 therein. Specifically, for example, the diameters of the openings 11 and 12 are larger than the width in the width direction (X direction) and the width in the thickness direction (Y direction) of the explosion-proof valve 111, respectively. Note that when the openings 11 and 12 of the flow path portion 10 each have a shape corresponding to the explosion-proof valve 111 of the battery cell 110 as described above, the gasket 1 can be attached to the battery module 100 regardless of the orientation of the gasket 1 in the axial z direction. However, only one of the openings 11 and 12 of the flow path portion 10 may have a shape corresponding to the explosion-proof valve 111 of the battery cell 110 as described above. In this case, in the battery module 100, the side of the openings 11 and 12 of the flow path portion 10 having a shape corresponding to the explosion-proof valve 111 faces the battery cell group 101.

[0041] The flow path portion 10 also has a recess 16 (see FIG. 6 described later). The recess 16 is a portion recessed from the lower end surface 15 toward the upper end surface 14, and penetrates between the outer peripheral surface 10a and the inner peripheral surface 10b. The recess 16 is a portion for connecting each of the grooves 3 communicating with the openings 12 of each flow path portion 10 to the flow path 13 of this flow path portion 10. The specific configuration of the recess 16 will be described later.

[0042] As shown in FIGS. 1 to 4 , the base 20 has a plate-like shape extending in the direction in which the multiple flow path sections 10 are arranged. The front surface 21 and the back surface 22 of the base 20 extend parallel or approximately parallel to each other, as shown in FIG. 4 , for example, and are flat or approximately flat, extending along a plane perpendicular to the axis x. The front surface 21 and the back surface 22 of the base 20 do not have to be flat. The front surface 21 and the back surface 22 may be curved surfaces, such as curved or wavy surfaces, or may be structured surfaces. A structured surface is a surface having a shape corresponding to a predetermined structure, such as a surface having a shape corresponding to the shape of the upper surface 110a of the battery cell 110 or the shape of the discharge pipe 120.

[0043] The openings 11 and 12 of the flow path section 10 are located further inward than the front surface 21 and back surface 22 of the base 20, respectively. That is, as shown in FIG. 4 , the width of the base 20 in the axial x direction is larger than the width of the flow path section 10 in the axial x direction, and the front surface 21 of the base 20 is above the upper end surface 14 of the flow path section 10, and the back surface 22 of the base 20 is below the lower end surface 15 of the flow path section 10. The upper side refers to the side toward which the front surface 21 faces in the axial x direction, and the lower side refers to the side toward which the back surface 22 faces in the axial x direction. Furthermore, for example, the width in the axial x direction between the upper end surface 14 of the flow path section 10 and the front surface 21 of the base 20 and the width in the axial x direction between the lower end surface 15 of the flow path section 10 and the back surface 22 of the base 20 are the same or approximately the same.

[0044] 4 and 5 , the base 20 is formed with a through-hole surface 25 that defines a through-hole 24 that accommodates the flow path section 10. The through-hole surface 25 is a cylindrical surface that corresponds to the outer peripheral surface 10a, which is the outer peripheral surface of the flow path section 10, and extends along the axis x. The through-hole surface 25 extends between the front surface 21 and the back surface 22 of the base 20, and the through-hole 24 penetrates the base 20 between the front surface 21 and the back surface 22. The through-hole surface 25 contacts the outer peripheral surface 10a of the flow path section 10, thereby holding the flow path section 10 to the base 20. The flow path section 10 is held to the base 20, for example, by being fitted to the through-hole surface 25. The flow path section 10 is held to the base 20, for example, by being bonded to the through-hole surface 25. Note that the flow path section 10 may be held in the base 20 in other ways. As described above, the surface 21 of the base 20 is located above the upper end surface 14 of the flow path section 10, and the back surface 22 of the base 20 is located below the lower end surface 15 of the flow path section 10. Therefore, as shown in Figure 5, the flow hole surface 25 and the flow hole 24 are respectively formed with an upper flow hole surface 25a and an upper flow hole section 24a, which are portions located above the upper end surface 14 of the flow path section 10, and a lower flow hole surface 25b and a lower flow hole section 24b, which are portions located below the lower end surface 15 of the flow path section 10.

[0045] The through-hole surface 25 of the base 20 has a shape corresponding to the outer peripheral surface 10a of the flow path section 10, and is, for example, a cylindrical or approximately cylindrical surface with the axis x as its central axis or approximately central axis. The through-hole surface 25 of the base 20 is not limited to a cylindrical surface. For example, the through-hole surface 25 may be a polygonal cylindrical surface. The cross-sectional shape of the through-hole surface 25 perpendicular to the axis x is not limited to a circle but may be an ellipse, another circular shape, a polygon, or the like. The shape of the upper through-hole surface 25a of the through-hole surface 25 may be different from the shape of the portion of the through-hole surface 25 that contacts the outer peripheral surface 10a of the flow path section 10 (contact surface 25c). Similarly, the shape of the lower through-hole surface 25b of the through-hole surface 25 may be different from the shape of the contact surface 25c of the through-hole surface 25. The shapes of the upper through-hole surface 25a and the lower through-hole surface 25b may be the same or different from each other. 5, the upper crushing margin d1, which is the width of the upper through-hole surface 25a of the base 20 in the axial x direction, and the lower crushing margin d2, which is the width of the lower through-hole surface 25b of the base 20 in the axial x direction, are the same or approximately the same. Note that the upper crushing margin d1 and the lower crushing margin d2 may be different from each other.

[0046] The base 20 has an upper flow hole portion 24a and a lower flow hole portion 24b defined by the above-described upper flow hole surface 25a and the lower flow hole surface 25b, respectively. Therefore, in the gasket 1, the opening 11 of the flow path portion 10 is open to the space outside the gasket 1 via the upper flow hole portion 24a of the base 20, and the opening 12 of the flow path portion 10 is open to the space outside the gasket 1 via the lower flow hole portion 24b of the base 20.

[0047] The upstream and downstream flow holes 24a and 24b of the base 20 each have a shape corresponding to the explosion-proof valve 111 of the battery cell 110, and are shaped to accommodate the explosion-proof valve 111 therein, for example. Specifically, for example, the diameters of the upstream and downstream flow holes 24a and 24b are larger than the width in the width direction (X direction) and the width in the thickness direction (Y direction) of the explosion-proof valve 111, respectively. Note that when the upstream and downstream flow holes 24a and 24b of the base 20 each have a shape corresponding to the explosion-proof valve 111 of the battery cell 110 as described above, the gasket 1 can be attached to the battery module 100 regardless of the orientation of the gasket 1 in the axial z direction. However, only one of the upstream and downstream flow holes 24a and 24b of the base 20 may have a shape corresponding to the explosion-proof valve 111 of the battery cell 110 as described above. In this case, in the battery module 100, the side of the base 20 having the upper flow hole portion 24a or the lower flow hole portion 24b, which has a shape corresponding to the explosion-proof valve 111, is on the battery cell group 101 side.

[0048] 1 to 5, the base 20 has a recessed portion 31 between two adjacent flow path portions 10. The recessed portion 31 is recessed from a pair of surfaces 21, 22 of the base 20. Specifically, for example, the recessed portion 31 penetrates the base 20 between two adjacent flow hole surfaces 25, and is recessed from each of the front surface 21 and the back surface 22. The base 20 is not solid between two adjacent flow hole surfaces 25, and a recessed portion 31 is formed between the two adjacent flow hole surfaces 25, penetrating the base 20 in the direction of the axis x. The recessed portion 31 is a through hole penetrating between the front surface 21 and the back surface 22, for example, as shown in FIG.

[0049] 2 to 4, the base 20 has a peripheral wall portion 32 formed by a lightening portion 31 around the through hole 24, the peripheral wall portion 32 extending in the direction of the axis x. The peripheral wall portion 32 forms a part of the through hole surface 25, and has a thickness that increases from the through hole surface 25 toward the outer periphery. Also, as shown in FIGS. 2 and 3, the base 20 has a pair of side wall portions 33 and 34 formed by the lightening portion 31, the side wall portion 33 and the side wall portion 34 being a pair of portions that extend in the arrangement direction of the flow path portion 10. The side wall portion 33 and the side wall portion 34 face each other via the peripheral wall portion 32 and are integrally connected to the peripheral wall portion 32. The side wall portion 33 and the side wall portion 34 each form a part of the through hole 24.

[0050] It should be noted that the cutout portions 31 are not limited to those that penetrate the base 20 as described above. For example, the cutout portions 31 may be recessed from the front surface 21 and not penetrate the back surface 22. Furthermore, for example, the cutout portions 31 may be recessed from the back surface 22 and not penetrate the front surface 21. Furthermore, the base 20 does not necessarily have to have cutout portions 31 between every pair of adjacent communication holes 24, and there may be a portion between every pair of adjacent communication holes 24 where no cutout portion 31 is provided.

[0051] As described above, a plurality of grooves 3 are formed in the back surface 22 of the base 20. At least one groove 3 is connected to the opening 12 of each flow path portion 10, and the grooves 3 extend to the edge 23 of the back surface 22. Specifically, as shown in FIG. 3 , the grooves 3 extend between each through-hole surface 25 and the edge 23 of the back surface 22. The edge 23 is the edge of the back surface 22 that defines the outline of the back surface 22, excluding the outline at the through-hole surface 25. The edge 23 of the back surface 22 includes an edge 23a that defines the outline of the outer periphery of the back surface 22, including the outline of the back surface 22 at the side wall portions 33 and 34, and an edge 23b that defines the outline of the back surface 22 at the lightening portion 31. As shown in FIG. 3 , for example, a plurality of grooves 3 are provided around each through-hole 24. The plurality of grooves 3 provided around each through-hole 24 are, for example, spaced apart around the axis x. Specifically, the plurality of grooves 3 provided around each of the flow holes 24 are provided at equal or approximately equal angular intervals around the axis x.

[0052] As shown in FIG. 3 , for example, four grooves 3 are provided around each flow hole 24 at equal or approximately equal angular intervals around the axis x. Two of the four grooves 3 extend along the direction in which the flow path sections 10 are arranged (the Y direction) and, for example, face each other across the flow hole 24. The other two of the four grooves 3 extend along a direction perpendicular to the direction in which the flow path sections 10 are arranged (the X direction) and, for example, face each other across the flow hole 24. Each of the two grooves 3 extending in the Y direction extends between the flow hole surface 25 and an end 23 b of the lightening portion 31, with one end opening to the flow hole 24 and the other end opening to the lightening portion 31. Each of the two grooves 3 extending in the X direction extends between the flow hole surface 25 and an end 23 a on the outer circumferential side of the back surface 22 and, for example, opens to the flow hole 24 and, for example, opens to the outside of the side wall section 33 or the side wall section 34.

[0053] As described above, a portion of the groove 3 is closed between the battery cell 110 and the discharge pipe 120. Specifically, when the gasket 1 is in use and compressed and sandwiched between the upper surface 110 a of each of the arranged battery cells 110 and the discharge pipe 120, a portion of the groove 3 contacts the upper surface 110 a of the battery cell 110, which is in contact with the back surface 22 of the base 20. Specifically, for example, a portion of the groove 3 is shallower than other portions of the groove 3. That is, the depth (depth D) of the groove 3 is smaller in some portions than in other portions. When the gasket 1 is in use, as the gasket 1 is compressed in the Z direction, the depth D of the groove 3 decreases, and the shallow portion of the groove 3 contacts the top surface 110 a of the battery cell 110. Note that the depth D of the groove 3 is the width of the groove 3 in the direction from the back surface 22 toward the front surface 21 (the Z-axis x direction), as shown in FIG. 5 .

[0054] Fig. 6 is an enlarged cross-sectional view showing the vicinity of the groove 3 of the gasket 1 shown in Fig. 5. Fig. 7 is a cross-sectional view of the gasket taken along line B-B in Fig. 6. Fig. 7 shows a cross-section perpendicular to the extension direction of the groove 3. As shown in Fig. 6, the groove 3 becomes shallower, for example, from the side of the opening 12 of the flow path portion 10 to which the groove 3 communicates toward the end 23 of the back surface 22. Fig. 6 shows the groove 3 extending in the Y direction, and the groove 3 shown in Fig. 6 extends to the end 23b of the back surface 22. Note that the groove 3 extending in the X direction has a similar shape, and its description will be omitted.

[0055] As shown in FIG. 6 , the groove 3 becomes shallower from the opening 12 side toward the end 23. Specifically, as shown in FIGS. 6 and 7 , the depth D of the groove 3 at the portion of the bottom surface 3a of the groove, which defines a space recessed from the back surface 22 of the groove 3 and is furthest from the back surface 22 toward the front surface 21, becomes smaller from the end 3b toward the end 3c. The depth D of the groove 3 is greatest (depth D2) at the end 3b and is smallest (depth D1) at the end 3c. The end 3b is the end of the groove 3 on the side of the through hole 24, and the end 3c is the end of the groove 3 on the side of the recessed portion 31. The groove 3 opens to the through hole 24 at the end 3b and to the recessed portion 31 at the end 3c. In the groove 3 extending in the X direction, the end 3c opens outward from the side wall portion 33 or the side wall portion 34. In the cross section shown in Fig. 6, for example, the bottom surface 3a of the groove 3 extends linearly or substantially linearly from the end 3b to the end 3c, inclined toward the back surface 22. Note that in the cross section shown in Fig. 6, the bottom surface 3a of the groove 3 may extend in a curved manner from the end 3b to the end 3c, inclined toward the back surface 22, or may extend in a line that includes a curved line and a straight line.

[0056] When the gasket 1 is in use, the groove 3 has an end 3c and a portion (hereinafter also referred to as a closing portion 4) of a predetermined width (width W) in the extension direction (Y direction) of the groove 3 from the end 3c toward the end 3b, which portion contacts the upper surface 110a of the battery cell 110. Specifically, as shown in Fig. 6 , the depth (depth D3) of the groove 3 at a position (position P) of width W in the extension direction (Y direction) of the groove 3 from the end 3c is smaller than the value of the crushing allowance d2 on the back surface 22 side of the gasket 1, and the value of the depth D of the groove 3 from position P toward the end 3c is smaller than the value of the crushing allowance d2.

[0057] Furthermore, the closing portion 4, which is the portion of the bottom surface 3a of the groove 3 that comes into contact with the upper surface 110a of the battery cell 110, is configured so that, as will be described later, when the gasket 1 is in use, gas released from the explosion-proof valve 111 enters the groove 3 and, under the pressure of this gas, the closing portion 4 moves away from the upper surface 110a. Specifically, for example, the width W and the depths D1 and D2 are each set to values ​​such that, as will be described later, when the gasket 1 is in use, the gas released from the explosion-proof valve 111 enters the groove 3 and, under the pressure of this gas, the closing portion 4 moves away from the upper surface 110a.

[0058] As shown in FIG. 7 , the bottom surface 3 a of the groove 3 has, for example, an arc-shaped or arc-like cross-sectional shape. The cross-sectional shape of the bottom surface 3 a of the groove 3 is not limited to an arc-shaped or arc-shaped cross-sectional shape. The bottom surface 3 a of the groove 3 may have other shapes, such as a flat or substantially flat shape extending along the back surface 22. The groove 3 may also be gradually shallower from end 3 b to end 3 c. In this case, for example, the bottom surface 3 a of the groove 3 has multiple steps descending toward the back surface 22 from end 3 b to end 3 c, forming a staircase-like shape. The bottom surface 3 a of the groove 3 may have various shapes. The shape of the bottom surface 3 a of the groove 3 is such that, in the gasket 1 in use, the closing portion 4 contacts the upper surface 110 a of the battery cell 110, and the closing portion 4, which contacts the upper surface 110 a of the battery cell 110, moves away from the upper surface 110 a due to the pressure of gas released from the explosion-proof valve 111.

[0059] As described above, the flow path portion 10 has recesses 16 formed therein. Specifically, as shown in FIG. 6 , the flow path portion 10 has recesses 16 formed therein, which connect the ends 3 b of the grooves 3 to the flow paths 13 defined by the flow path portion 10. The recesses 16 are recessed from the lower end surface 15 toward the upper end surface 14 and penetrate between the outer peripheral surface 10 a and the inner peripheral surface 10 b. The cross-sectional shape of the recesses 16 in the extension direction is, for example, the same as or substantially the same as the cross-sectional shape of the bottom surfaces 3 a of the grooves 3 in the extension direction (see FIG. 7 ). Note that the cross-sectional shape of the recesses 16 in the extension direction does not have to be the same as the cross-sectional shape of the bottom surfaces 3 a of the grooves 3 in the extension direction, as long as it connects the ends 3 b of the corresponding grooves 3 to the flow paths 13. Each flow path portion 10 has recesses 16 corresponding to the grooves 3 that connect to the openings 12 of the flow path portion 10. In this example, four recesses 16 are provided.

[0060] As described above, the hardness of the base body 20 is lower than the hardness of the flow path portion 10. Specifically, the base body 20 is a low-hardness member. For example, the base body 20 has a low hardness but a hardness that allows it to maintain its shape in a natural state without receiving external force. Furthermore, for example, the base body 20 has a hardness that generates a reaction force when compressed. Specifically, when the gasket 1 is in use and the base body 20 is compressed between the upper surfaces of the plurality of battery cells 110 of the battery cell group 101 and the discharge pipe 120, the base body 20 has a hardness that generates a reaction force on each of the upper surfaces of the plurality of battery cells 110 and the discharge pipe 120. Furthermore, for example, the base body 20 has a hardness that allows it to deform under the pressure of the gas discharged from the sealed object, i.e., the explosion-proof valve 111.

[0061] Specifically, for example, the base 20 is a low-hardness member that has a hardness that allows it to maintain its shape in a natural state where it is not subjected to external force, has a hardness that generates a reaction force when compressed in a state of use, and has a hardness that allows it to deform under the pressure of the gas released from the explosion-proof valve 111. Note that the form of the base 20 is not limited to one having such hardness.

[0062] The hardness of the base body 20 is set to a hardness that allows it to deform in accordance with the shape of the object to which it is attached when assembling the battery module 100. Specifically, the hardness of the base body 20 is set to a low hardness that allows it to deform in accordance with the shape of the upper surfaces 110a of the plurality of battery cells 110 and the shape of the discharge pipe 120 when the gasket 1 is attached to the upper surfaces 110a of the plurality of battery cells 110 of the battery cell group 101 and when the gasket 1 is attached to the discharge pipe 120 when assembling the battery module 100. When the gasket 1 is attached to the upper surfaces 110a of the plurality of battery cells 110 of the battery cell group 101, the base body 20 may be pressed against the upper surfaces 110a of the plurality of battery cells 110 or may be pressed against the discharge pipe 120, for example, by the force of an operator or the force of an assembly machine. Furthermore, the deformation of the base 20 in response to the shape of the upper surfaces 110a of the plurality of battery cells 110 during installation of the gasket 1 described above does not have to be such that the base 20 completely conforms to the shape of the upper surfaces 110a of the plurality of battery cells 110. For example, the deformation of the base 20 may be such that a portion of the base 20 comes into contact with a portion of the upper surfaces 110a of the plurality of battery cells 110, or such that a portion of the base 20 comes into engagement-capable contact with a portion of the upper surfaces 110a of the plurality of battery cells 110. Similarly, the deformation of the base 20 in response to the shape of the discharge pipe 120 during installation of the gasket 1 described above does not have to be such that the base 20 completely conforms to the shape of the discharge pipe 120. For example, the deformation of the base 20 may be such that a portion of the base 20 comes into contact with a portion of the discharge pipe 120, or such that a portion of the base 20 comes into engagement-capable contact with a portion of the discharge pipe 120.

[0063] The base 20 is made of, for example, low-hardness urethane having the hardness described above. However, the material of the base 20 is not limited to urethane. The material of the base 20 may be other elastic materials, such as low-hardness rubber or other elastomers having the hardness described above. For example, the compounding ratio of the compounding components of the material of the base 20 is adjusted so that the hardness of the base 20 becomes the desired low hardness described above. For example, when the material of the base 20 is urethane, the compounding ratio of the isocyanate component is adjusted to make the hardness of the base 20 the desired hardness.

[0064] Furthermore, the flow path portion 10 is heat-resistant and made of a heat-resistant material. For example, the flow path portion 10 is heat-resistant to the temperature of the gas released from the explosion-proof valve 111, which is the object to be sealed. Specifically, the temperature of the gas released from the explosion-proof valve 111 may reach 400°C or higher, and the flow path portion 10 has a heat resistance of, for example, 400°C or higher. The material of the flow path portion 10 is, for example, PTFE (polytetrafluoroethylene). The material of the flow path portion 10 may also be other materials having the above-mentioned heat resistance. Furthermore, the hardness of the flow path portion 10 is higher than the hardness of the base 20. For example, the hardness of the base 20 is such that it does not deform even when subjected to the pressure of the gas released from the explosion-proof valve 111.

[0065] The base body 20 may also have adhesiveness. The adhesiveness of the base body 20 is, for example, adhesiveness that allows the base body 20 to be fixed against a force based on the weight of the gasket 1. Specifically, the adhesiveness of the base body 20 is such that when the base body 20 is attached to the upper surfaces 110 a of the plurality of battery cells 110 of the battery cell group 101 or when the base body 20 is attached to the discharge pipe 120 during assembly of the battery module 100, the adhesiveness of the base body 20 allows the base body 20 to attach to the upper surfaces 110 a of the plurality of battery cells 110 or the discharge pipe 120, and the base body 20 does not separate from the battery cell group 101 or the discharge pipe 120 even when the attitude of the battery cell group 101 or the discharge pipe 120 is changed, for example, by tilting the battery cell group 101 or the discharge pipe 120. Furthermore, for example, the adhesiveness of the base 20 may be such that the base 20 does not separate from the battery cell group 101 or the discharge pipe 120 even when an external force that is not large enough to remove the base 20 is applied, such as when an unintentional worker or the like comes into contact with the base 20.

[0066] The degree of adhesiveness of the base body 20 is adjusted, for example, depending on the desired degree of adhesiveness. Specifically, for example, when the base body 20 is attached to the upper surfaces 110 a of the plurality of battery cells 110 of the battery cell group 101 or when the base body 20 is attached to the discharge pipe 120 during assembly of the battery module 100, the degree of adhesiveness of the base body 20 is adjusted based on the size of the contact area of ​​the base body 20 with the upper surfaces 110 a of the plurality of battery cells 110 or the discharge pipe 120. For example, if the contact area of ​​the base body 20 with the upper surfaces 110 a of the plurality of battery cells 110 or the discharge pipe 120 is large, the degree of adhesiveness of the base body 20 may be low. This is because, if the contact area of ​​the base body 20 with the upper surfaces 110 a of the plurality of battery cells 110 or the discharge pipe 120 is large, the adhesive area is large, and therefore, even if the adhesiveness is low, the base body 20 can be prevented from separating from the battery cell group 101 or the discharge pipe 120. On the other hand, when the contact area of ​​the base 20 with the upper surfaces 110a of the plurality of battery cells 110 or the discharge pipe 120 is small, the adhesive area is small, so it is better to have a high degree of adhesiveness of the base 20. In this way, for example, the degree of adhesiveness of the base 20 is adjusted to a value corresponding to the size of the contact area of ​​the base 20 with the attachment object, for example, to a value proportional to the size of the contact area of ​​the base 20 with the attachment object.

[0067] The degree of adhesiveness of the base 20 is adjusted, for example, by adjusting the material of the base 20. For example, when the material of the base 20 is urethane, the adhesiveness increases as the hardness of the base 20 decreases, and therefore the degree of adhesiveness of the base 20 is adjusted by adjusting the compounding ratio of the isocyanate component.

[0068] Next, a description will be given of the operation of the gasket 1 having the above-described configuration. Fig. 8 is a partial cross-sectional view of the battery module 100 showing a cross section of the gasket 1 in a state where it is attached to the battery module 100 and in use.

[0069] 8 , in use, the gasket 1 is sandwiched between the battery cell group 101 and the discharge pipe 120 to seal the flow path between each explosion-proof valve 111 and the corresponding opening 122 of the discharge pipe 120. Specifically, the surface 21 of the base 20 of the gasket 1 contacts the surface 120a of the discharge pipe 120, and the back surface 22 of the base 20 of the gasket 1 contacts the upper surface 110a of each battery cell 110 of the battery cell group 101, so that the gasket 1 is compressed between the upper surface 110a of each battery cell 110 and the discharge pipe 120. In addition, the explosion-proof valve 111 is surrounded by the lower hole surface 25b of each of the through-hole surfaces 25 of the base 20, and the opening 122 of the discharge pipe 120 is surrounded by the upper hole surface 25a of each of the through-hole surfaces 25 of the base 20. Furthermore, the surface 21 of the base 20 is in contact with the upper surface 110a around the explosion-proof valve 111 of each battery cell 110, and the back surface 22 of the base 20 is in contact with the surface 120a around each opening 122 of the release pipe 120. In this way, the base 20 of the gasket 1 allows the gas released from the explosion-proof valve 111 to flow into the release pipe 120 through the communication holes 24 without leaking.

[0070] As shown in Fig. 8 , in the used state, the base body 20 is compressed in the axial x direction and shrinks, for example, by the width of the upper crushing margin d1 and the lower crushing margin d2 (see Figs. 5 and 6 ). As a result, the upper end surface 14 and the lower end surface 15 of the flow path portion 10 contact the surface 120a of the discharge pipe 120 and the upper surface 110a of the corresponding battery cell 110. Therefore, as shown in Fig. 8 , in the used state, all or almost all of the flow hole surface 25 of the base body 20 of the gasket 1 is covered by the flow path portion 10. Note that in the used state, the base body 20 compressed in the axial x direction may shrink by a width smaller than the width of the upper crushing margin d1 and the lower crushing margin d2 (see Figs. 5 and 6 ). In this case, only the upper end surface 14 of the flow path portion 10 does not contact the surface 120a of the discharge pipe 120, only the lower end surface 15 of the flow path portion 10 does not contact the upper surface 110a of the corresponding battery cell 110, or both the upper end surface 14 and the lower end surface 15 of the flow path portion 10 do not contact the surface 120a of the discharge pipe 120 and the upper surface 110a of the corresponding battery cell 110, respectively. In this case, in the used state, there will be a portion of one or both of the upper flow hole surface 25a and the lower flow hole surface 25b of the flow hole surface 25 of the base 20 of the gasket 1 that is not covered by the flow path portion 10.

[0071] 8, in the use state, the upper end surface 14 of each flow path section 10 surrounds the corresponding opening 122 of the discharge pipe 120, and the lower end surface 15 of each flow path section 10 surrounds the corresponding explosion-proof valve 111. In the use state, the upper end surface 14 of each flow path section 10 does not have to surround the corresponding opening 122 of the discharge pipe 120, and part or all of the upper end surface 14 of each flow path section 10 may be within the corresponding opening 122 of the discharge pipe 120 when viewed in the direction of the axis x.

[0072] As described above, the through-hole surfaces 25 defining each of the through-holes 24 of the base 20 are covered by the heat-resistant flow path portion 10, and the high-temperature, high-pressure gas released from the explosion-proof valve 111 does not come into direct contact with the through-hole surfaces 25 defining each of the through-holes 24 of the base 20. If the through-hole surfaces 25 defining each of the through-holes 24 of the base 20 are not completely covered by the heat-resistant flow path portion 10, the through-hole surfaces 25 defining each of the through-holes 24 of the base 20 may be slightly exposed to the high-temperature, high-pressure gas released from the explosion-proof valve 111.

[0073] As described above, the base 20 has low hardness. Therefore, the base 20 can easily conform to the shape of the mounting surface of the battery cell group 101 with which the base 20 comes into contact, the upper surface 110a of the battery cell 110, and the surface 120a of the discharge pipe 120. Therefore, the base 20 can be easily attached to the mounting object to which the gasket 1 is attached, and the gasket 1 can be easily attached to the mounting object. In this way, the base 20 has high conformability to the object with which the base 20 comes into contact. Therefore, the gasket 1 can be easily assembled to the mounting object.

[0074] Furthermore, the base 20 has adhesiveness. This allows the base 20 to adhere to the mounting surface of the battery cell group 101 with which the base 20 comes into contact, the upper surface 110a of the battery cell 110, and the surface 120a of the discharge pipe 120. This makes it easy to attach the base 20 to the mounting object to which the gasket 1 is to be attached, and the gasket 1 is easy to attach to the mounting object. This also makes it easy to assemble the gasket 1 to the mounting object.

[0075] Furthermore, because the base 20 has a low hardness, when the flow hole surface 25 of the base 20 is exposed to the high-pressure gas released from the explosion-proof valve 111, the flow hole surface 25 is deformed, and ultimately the base 20 is deformed. When the base 20 is deformed, the sealing ability of the gasket 1 is reduced. However, in the gasket 1, the flow hole surface 25 of the base 20 is covered by the flow path portion 10, which has a high hardness, and the high-pressure gas released from the explosion-proof valve 111 does not directly contact the flow hole surface 25 of the base 20. In this way, the flow hole surface 25 of the base 20 is protected from the high-pressure gas released from the explosion-proof valve 111 by the flow path portion 10, which has a higher hardness and a higher pressure resistance than the base 20, and deformation of the flow hole surface 25 due to the high-pressure gas released from the explosion-proof valve 111 is prevented or suppressed. Therefore, in the gasket 1, the hardness of the base 20 can be reduced to improve attachment, etc., and even if the base 20 has such low hardness that it is deformed by the pressure of the gas released from the explosion-proof valve 111, deformation of the flow hole surface 25 due to the high-pressure gas released from the explosion-proof valve 111 is prevented or suppressed. In this way, the gasket 1 has excellent pressure resistance.

[0076] Furthermore, the flow path portion 10 has high heat resistance. Therefore, the heat of the high-temperature gas released from the explosion-proof valve 111 that is transmitted to the flow hole surface 25 of the base 20 is blocked or reduced by the flow path portion 10. As a result, the base 20 is not melted by the high-temperature gas released from the explosion-proof valve 111, or is prevented from melting by the high-temperature gas released from the explosion-proof valve 111. In this way, the gasket 1 has excellent heat resistance.

[0077] As described above, even if the flow path portion 10 does not completely cover the through-hole surface 25 of the base 20, it is possible to reduce the amount of high-pressure gas released from the explosion-proof valve 111 that contacts the through-hole surface 25 of the base 20. Therefore, even with the flow path portion 10 that does not completely cover the through-hole surface 25 of the base 20, it is possible to suppress deformation of the through-hole surface 25 due to the high-pressure gas released from the explosion-proof valve 111. Therefore, even in this case, the gasket 1 has excellent pressure resistance.

[0078] Furthermore, even if the through-hole surface 25 of the base 20 is not completely covered by the flow path portion 10, it is possible to reduce the amount of high-temperature gas released from the explosion-proof valve 111 that contacts the through-hole surface 25 of the base 20. Therefore, even with the flow path portion 10 that does not completely cover the through-hole surface 25 of the base 20, it is possible to suppress melting of the through-hole surface 25 due to the high-temperature gas released from the explosion-proof valve 111. Therefore, even in this case, the gasket 1 has excellent heat resistance.

[0079] As described above, the gasket 1 according to the embodiment of the present invention can have high conformability to the object with which it comes into contact, and can have excellent heat resistance and pressure resistance.

[0080] Furthermore, when the gasket 1 is in use, the base 20 is compressed and crushed by the aforementioned crushing margins d1 and d2, whereby the closing portions 4 of the bottom surfaces 3a of the grooves 3 are crushed and come into contact with the upper surfaces 110a of the corresponding explosion-proof valves 111. Thus, when the gasket 1 is in use, the closing portions 4 of the grooves 3 close the grooves 3 from the outside of the base 20. In other words, the end 3c side of the grooves 3 is not open to the outside of the base 20. On the other hand, even when the base 20 is compressed when the gasket 1 is in use, the portion of the bottom surface 3a of the grooves 3 closer to the end 3b than the closing portions 4 does not come into contact with the upper surfaces 110a of the battery cells 110, maintaining the space of the grooves 3 in this portion. Furthermore, as described above, the flow path portion 10 has recesses 16 formed therein corresponding to the grooves 3. When the gasket 1 is in use, each groove 3 is open to the flow holes 24 at its end 3b via the recesses 16.

[0081] Therefore, when gas is released from the explosion-proof valve 111 of the battery cell 110, high-pressure gas enters the groove 3 through the recess 16 of the flow path portion 10. The closing portion 4 of the groove 3 is crushed and in contact with the upper surface 110a of the battery cell 110, but the closing portion 4 moves away from the upper surface 110a when the gas pressure of the gas released from the explosion-proof valve 111 in the flow hole 24 reaches a predetermined pressure or higher. Furthermore, the value of the depth D of the groove 3 at the closing portion 4 is smaller than the value of the crushing allowance d2, and the surface pressure between the closing portion 4 and the upper surface 110a is smaller than the surface pressure between the back surface 22 and the upper surface 110a. Therefore, even if high-pressure gas enters the groove 3 and the closing portion 4 of the groove 3 moves away from the upper surface 110a, contact between the back surface 22 of the base 20 and the upper surface 110a is maintained.

[0082] Because the gas is released instantaneously from the explosion-proof valve 111, the time it takes for the gas released from the explosion-proof valve 111 in the communication hole 24 to reach or exceed the predetermined pressure described above is also instantaneous, the time it takes for the closing portion 4 of the groove 3 to separate from the upper surface 110a and for the groove 3 to be opened to the outside of the base 20 at the end 3c is also instantaneous, and the time it takes for the high-pressure gas to be released from the groove 3 is also instantaneous. For this reason, the amount of gas released from the groove 3 is small and can be kept within an allowable range.

[0083] As described above, in the gasket 1, when the pressure inside the flow hole 24 becomes high due to the gas released from the explosion-proof valve 111, the closing portion 4 of the groove 3 is opened, and the gas inside the flow hole 24 is released. Therefore, the gas pressure inside the flow hole 24 due to the gas released from the explosion-proof valve 111 is prevented from becoming even higher than the gas pressure when the closing portion 4 is opened. Therefore, gas with a higher pressure than the predetermined gas pressure is prevented from entering between the back surface 22 of the base 20 and the upper surface 110a of the battery cell 110. Therefore, deformation of the base 20 at the back surface 22 can be prevented, and damage to the portion of the base 20 at the back surface 22 can be prevented. Therefore, deterioration of the sealing performance of the gasket 1 due to damage to the base 20 can be prevented.

[0084] As described above, the base 20 of the gasket 1 has low hardness and is easily deformed and damaged. However, the groove 3 keeps the gas pressure in the communication holes 24 of the gas released from the explosion-proof valve 111 at a constant value or below a substantially constant value. Therefore, even if the base 20 has low hardness, it is possible to prevent damage by the gas released from the explosion-proof valve 111.

[0085] As described above, the gasket 1 according to the embodiment of the present invention can prevent the base body 20 from being deformed or damaged by the gas released from the explosion-proof valve 111 .

[0086] Furthermore, in the gasket 1, the base body 20 is formed with the lightening hole 31 as described above. Therefore, when the base body 20 is compressed while the gasket 1 is in use, the peripheral wall portion 32 and the side wall portions 33, 34 can deform toward the lightening hole 31. Therefore, while the gasket 1 is in use, it is possible to prevent the filling rate of the base body 20 from increasing beyond an allowable range that would cause damage to the base body 20. Meanwhile, it is possible to ensure sealing between the base body 20 and the battery cell group 101 and the discharge pipe 120.

[0087] As described above, for example, the shape of the hollowed-out portion 31 is adjusted, and the thicknesses of the peripheral wall portion 32, the side wall portion 33, and the side wall portion 34 are adjusted so that the filling rate of the base 20 becomes a desired value and the base 20 has the desired sealing properties.

[0088] As described above, the gasket 1 according to an embodiment of the invention can have high conformability to the object it comes into contact with, and has excellent pressure resistance and heat resistance, which can prevent deformation or damage due to gas released from the explosion-proof valve 111.

[0089] In addition, in a state of use, when the base body 20 compressed in the axial x direction shrinks by a width smaller than the width of the lower crushing margin d2 (see FIGS. 5 and 6 ), the lower end surface 15 of the flow portion 10 does not contact the upper surface 110a of the corresponding battery cell 110, and there is a portion of the lower flow hole surface 25b that is not covered by the flow path portion 10. In this case, the end 3b of the groove 3 is open to the lower flow hole surface 25b, and the recess 16 does not need to be formed in the flow path portion 10.

[0090] In the above-described gasket 1, the flow path portions 10 are held in each of the plurality of through holes 24 penetrating the base 20 between the front surface 21 and the back surface 22. However, the plurality of flow path portions 10 may be embedded in the base 20 so that each of the plurality of through holes 24 is housed in the flow path 13 inside the flow path portion 10. Specifically, in the above-described gasket 1, the entire inner circumferential surface 10b of the flow path portion 10 is exposed to the through holes 24. However, the inner circumferential surface 10b of the flow path portion 10 may be covered by the base 20. For example, as shown in FIG. 9, the flow path portion 10 may be embedded in the base 20. In this case, the gasket 1 can be easily manufactured by insert molding. Note that FIG. 9 shows a cross section corresponding to FIG. 5. In this case, one or both of the upper end surface 14 and the lower end surface 15 of the flow path portion 10 may be exposed from the base 20. Furthermore, a portion of the inner circumferential surface 10b of the flow path portion 10 may be covered by the base 20. In this case, the groove 3 is formed so as to penetrate the recess 16 of the flow path portion 10. The recess 16 is located between the end 3b and the end 3c of the groove 3.

[0091] Furthermore, in the above-described gasket 1, a lightening portion 31 is formed between two adjacent flow holes 24, but the lightening portion 31 does not have to be formed in the base 20. In this case, the groove 3 extends on the back surface 22 from the flow hole surface 25 to the outer peripheral end 23a, and at the end 3c, for example, the groove 4 opens outward from the side wall portion 33 or the side wall portion 34. Note that the groove 3 may also open outward at the end 3c from the portions between both ends of the side wall portion 33 and both ends of the side wall portion 34, which are the ends in the extension direction (Y direction) of the base 20.

[0092] Although the present invention has been described above through the above embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention.

[0093] The above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the scope of the present invention. Furthermore, the above-described embodiments do not limit the scope of the present invention, and the present invention may include any and all applications. The components of the above-described embodiments, as well as their arrangement, materials, conditions, shape, size, etc., are not limited to those illustrated and may be modified as appropriate. For example, the present invention includes differences that arise during implementation due to manufacturing tolerances, etc. Furthermore, components illustrated in different embodiments may be partially substituted or combined within the scope of technical inconsistency. Furthermore, the various configurations may be selectively combined as appropriate to achieve at least some of the above-described problems and effects.

[0094] For example, the base 20 may not have the groove 3 on the back surface 22. In this case, the base 20 may have, for example, a through-hole that performs the same function as the groove 3. In this case, the flow path portion 10 does not have the recess 16, but has a through-hole that has the same function as the recess 16.

[0095] 1 Gasket, 3 Groove, 3a Bottom surface, 3b, 3c End, 4 Closure portion, 10 Flow path portion, 10a Outer peripheral surface, 10b Inner peripheral surface, 11, 12 Opening, 13 Flow path, 14 Upper end surface, 15 Lower end surface, 16 Recess, 20 Base, 21 Surface, 22 Back surface, 23, 23a, 23b End, 25 Flow hole surface, 25a Upper flow hole surface, 25b Lower flow hole surface, 25c Contact surface, 24 Flow hole, 24a Upper flow hole portion, 24b Lower flow hole portion, 31 Lightening portion, 32 Peripheral wall portion, 33, 34 Side wall portion, 100 Battery module, 101 Battery cell group, 110 Battery cell, 110a Upper surface, 111 Explosion-proof valve, 112 Electrode, 120 Discharge pipe, 120a Surface, 121 Discharge port, 122 Opening, 123 Gas discharge path, D, D1, D2, D3 Depth, d1, d2 Crushing allowance, P Position, W Width, x, y, z axis

Claims

1. A gasket for sealing an object between two members, comprising: a flow path portion which is a tubular member having a plurality of pairs of openings; and a base having a pair of surfaces facing each other, wherein the base is elastic; the flow path portion is held by the base so that the pair of openings are respectively open from the pair of surfaces of the base to form a flow path for the object to be sealed; the hardness of the base is lower than the hardness of the flow path portion; the base is compressed between the two members, and the pair of surfaces respectively come into contact with the two members; and a part of the contact between one of the pair of surfaces and one of the two members is released when the air pressure in the flow path portion rises.

2. The gasket according to claim 1, wherein the contact between said one surface and said one member is formed on the edge side of said one surface.

3. A gasket as set forth in claim 1 or 2, wherein when the air pressure reaches or exceeds a predetermined level, a portion of the contact between the one surface and the one member is released.

4. A gasket as claimed in claim 1, wherein said one surface has a plurality of grooves formed therein that are recessed towards the other side of said pair of surfaces, at least one of said grooves is connected to the opening on said one surface side of each of said plurality of flow path portions, said plurality of grooves extend to the edge of said one surface, and a portion of said groove is adapted to be blocked between said two members.

5. A gasket as set forth in claim 4, wherein a portion of said groove is adapted to contact a portion of one of said members between said two members.

6. A gasket according to claim 4 or 5, wherein a portion of the groove is shallower than another portion of the groove.

7. A gasket according to claim 6, wherein the groove becomes shallower from the side of the opening of the flow path portion with which the groove communicates toward the end of the one surface.

8. The gasket according to claim 7, wherein the groove becomes continuously shallower from the side of the opening toward the end.

9. The gasket according to claim 7, wherein the grooves become gradually shallower from the side of the opening toward the end.

10. A gasket according to claim 5, wherein the depth of the groove in a portion of the groove is smaller than the crushing allowance on the side of the one surface of the base body.

11. The gasket of claim 4, wherein said edge of said one surface forms a contour of said one surface.

12. A gasket according to claim 4, wherein the base has a plurality of through holes penetrating the base between the pair of surfaces, and the flow path portion is held in each of the plurality of through holes.

13. A gasket as set forth in claim 4, wherein the base has a plurality of through holes penetrating the base between the pair of surfaces, and the plurality of flow path portions are embedded in the base so that each of the plurality of through holes is housed inside the flow path portion.

14. A gasket according to claim 12 or 13, wherein the pair of openings of the flow path portion are respectively positioned inside the pair of surfaces of the base body.

15. The gasket of claim 1, wherein the substrate is formed from a low-hardness material, and the low-hardness material includes rubber, urethane, and elastomer.

16. A gasket according to claim 1, wherein the flow path portion is formed from a heat-resistant material, and the heat resistance of the flow path portion is heat resistance against the temperature of the object to be sealed.

17. The gasket of claim 16, wherein the material is PTFE.

18. A gasket according to claim 1, wherein the base has a recess between two adjacent flow path portions, and the recess is recessed from a pair of surfaces of the base.

19. A gasket as described in claim 1, wherein one of the two members is a plurality of battery cells of a battery module, the other of the two members is a gas release section that forms a space for guiding gas released from the explosion-proof valves of each of the plurality of battery cells, the object to be sealed is the gas released from the plurality of explosion-proof valves, and the plurality of flow path sections each form a flow path for the gas released from the plurality of explosion-proof valves.

Images