gasket

Abstract

To provide a gasket that offers high conformability to the object it contacts, and excellent pressure resistance and heat resistance. [Solution] The gasket 1 comprises a flow channel section 10, which is a cylindrical member having a plurality of pairs of openings 11, 12, and a base body 20 having a pair of surfaces facing each other, namely a surface 21 and a back surface 22. The base body 20 is elastic. The flow channel section 10 is held in the base body 20 such that the openings 11, 12 are open from the surface 21 and back surface 22 of the base body 20, respectively, so as to form a flow channel for the object to be sealed. The hardness of the base body 20 is lower than the hardness of the flow channel section 10.

Description

TECHNICAL FIELD

[0001] The present invention relates to a gasket.

BACKGROUND ART

[0002] A battery module having a plurality of battery cells, such as a lithium ion battery module, is provided with a gas discharge path that guides gas discharged from explosion-proof valves provided in each battery cell to the outside. The explosion-proof valve of each battery cell communicates with the gas discharge path, and the gas discharged from the explosion-proof valve of each battery cell is guided to the outside through the gas discharge path. In the battery module, when the internal pressure inside the battery cells becomes high due to gas generated in each battery cell, the gas is discharged to the outside via the explosion-proof valve. Further, a gasket is provided between the explosion-proof valve of each battery cell and the gas discharge path, the gasket seals the communication path between the explosion-proof valve and the gas discharge path, and prevents the gas discharged from the explosion-proof valve from leaking out of the gas discharge path (for example, see Patent Document 1).

[0003] Such a gasket for a battery module needs to be in close contact with the battery module and the gas discharge path in order to seal the gas discharged from the explosion-proof valve. For this reason, the gasket is of low hardness with low reaction force, and is formed of a foam material such as foamed silicone foam or urethane foam, for example. If the gasket has low hardness, the reaction force generated when the gasket is deformed is low, and the conformability to the shape of the object in contact with the gasket is enhanced.

PRIOR ART DOCUMENTS

PATENT DOCUMENTS

[0004]

PATENT DOCUMENT 1

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] The gas released from explosion-proof valves is under high pressure. Furthermore, the gas released from explosion-proof valves is at high temperature, sometimes exceeding 400°C. Therefore, conventional gaskets made from foam materials, due to their foamed structure, are prone to deformation, which can lead to leakage of the high-pressure gas released from the explosion-proof valves. Additionally, conventional gaskets made from foam materials can melt when exposed to the gas released from explosion-proof valves.

[0006] Thus, conventional gaskets for explosion-proof valves require a structure that offers high conformability to the object they come into contact with, as well as excellent pressure resistance and heat resistance.

[0007] The present invention has been made in view of the above-mentioned problems, and its objective is to provide a gasket that has high conformability to the object it comes into contact with, and excellent pressure resistance and heat resistance. [Means for solving the problem]

[0008] To achieve the above objective, the gasket according to the present invention is a gasket for sealing an object to be sealed between two members, comprising: a plurality of cylindrical members having a pair of openings, a flow channel portion, and a base having a pair of surfaces facing each other, wherein the base is elastic, and the flow channel portion is held by the base such that the pair of openings are each open from the pair of surfaces of the base so as to form a flow channel for the object to be sealed, and the hardness of the base is lower than the hardness of the flow channel portion.

[0009] In a gasket according to one aspect of the present invention, the substrate has a hardness that allows it to maintain its shape in a natural state without being subjected to external force.

[0010] In a gasket according to one aspect of the present invention, the substrate has a hardness that generates a reaction force when compressed between the two members.

[0011] In a gasket according to one aspect of the present invention, the substrate has a hardness that allows it to deform under pressure from the object to be sealed.

[0012] In a gasket according to one aspect of the present invention, the substrate is formed from a low-hardness material, and the low-hardness material includes rubber, urethane, and elastomer.

[0013] In a gasket according to one aspect of the present invention, the flow channel portion is formed of a heat-resistant material.

[0014] In a gasket according to one aspect of the present invention, the heat resistance of the flow path portion is the heat resistance to the temperature of the object to be sealed.

[0015] In a gasket according to one aspect of the present invention, the material is PTFE.

[0016] In a gasket according to one aspect of the present invention, the substrate is adhesive.

[0017] In a gasket according to one aspect of the present invention, the adhesiveness of the substrate is such that it is able to fix the substrate against a force based on the weight of the gasket itself.

[0018] In a gasket according to one aspect of the present invention, the substrate has a recess between two adjacent flow channels, and the recess is recessed in the direction facing a pair of surfaces of the substrate.

[0019] In a gasket according to one aspect of the present invention, 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 portion that forms a space for guiding the gas released from each of the explosion-proof valves 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 portions each form a flow path for the gas released from the plurality of explosion-proof valves. [Effects of the Invention]

[0020] The gasket according to the present invention can be made highly conformable to the object it comes into contact with, and can have excellent pressure resistance and heat resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] [Figure 1] FIG. 2 is a schematic exploded perspective view showing a battery module in which a gasket according to a first embodiment of the present invention is used. [Figure 2] FIG. 2 is a plan view of the gasket shown in FIG. 1. [Figure 3] FIG. 2 is a cross-sectional view of the gasket showing a cross section taken along line A-A in FIG. 2. [Figure 4] FIG. 3 is an enlarged cross-sectional view showing, in an enlarged manner, the vicinity of a flow passage portion of the gasket shown in FIG. 3. [Figure 5] FIG. 2 is a partial cross-sectional view of the battery module showing a cross section of the gasket in a usage state attached to the battery module. [Figure 6] FIG. 2 is a partially enlarged cross-sectional view showing a modified example of the gasket according to the first embodiment of the present invention. [Figure 7] FIG. 2 is a plan view of a gasket according to a second embodiment of the present invention. [Figure 8] FIG. 2 is a cross-sectional view showing a modified example of the gasket according to the second embodiment of the present invention. [Figure 9] FIG. 2 is a cross-sectional view showing a modified example of the gasket according to the second embodiment of the present invention. MODES FOR CARRYING OUT THE INVENTION

[0022] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that, in the drawings, reference numerals may not be assigned to all of a plurality of constituent elements, and reference numerals for some of the plurality of constituent elements may be omitted. The gasket according to the present invention is, as an example, used in a battery module having a plurality of battery cells, such as a lithium ion battery module, and seals gas discharged from an explosion-proof valve provided in each battery cell.

[0023] Figure 1 is a schematic exploded perspective view showing a battery module 100 in which the gasket 1 according to the first embodiment of the present invention is used. Figure 2 is a plan view of the gasket 1, and Figure 3 is a cross-sectional view of the gasket 1 showing a cross section along line AA in Figure 2. The gasket 1 is a gasket for sealing the gas released from the explosion-proof valves 111, which are the objects to be sealed, between the plurality of battery cells 110 of the battery module 100 and the discharge pipe 120, which is a gas discharge section that forms a space for guiding the gas released from each of the explosion-proof valves 111 of the plurality of battery cells 110.

[0024] As shown in Figures 1-3, the gasket 1 comprises a flow channel section 10, which is a cylindrical member having a plurality of pairs of openings 11 and 12, and a base body 20 having a pair of surfaces facing each other, namely a front surface 21 and a back surface 22. The base body 20 is elastic. The flow channel section 10 is held by the base body 20 such that the openings 11 and 12 are open from the front surface 21 and back surface 22 of the base body 20, respectively, to form a flow channel for the object to be sealed. The hardness of the base body 20 is lower than the hardness of the flow channel section 10. The configuration of the gasket 1 will be described in detail below.

[0025] As shown in Figure 1, in the battery module 100, a plurality of battery cells 110 are arranged in a row and fixed by fasteners (not shown). An insulating resin (not shown), for example, is interposed between the battery cells 110. The plurality of battery cells 110 are connected to form a battery cell group 101. The battery cells 110 are rechargeable batteries, such as lithium-ion batteries. Each battery cell 110 has an external shape such as a rectangular shape in which the length in the width direction (X direction) is longer than the height direction (Z direction) and the thickness direction (Y direction) is thin. The battery cells 110 are arranged in the Y direction.

[0026] Each battery cell 110 has an explosion-proof valve 111 as described above, and also has a pair of electrodes 112. The explosion-proof valve 111 and 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, with one being the positive electrode and the other the negative electrode. The explosion-proof valve 111 is located in the central part in the width direction. In secondary batteries such as lithium-ion batteries, gas can be generated inside due to charging and discharging during use or external factors, causing the internal pressure to rise. 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 inside the battery cell 110 from rising to an unacceptable level.

[0027] The discharge pipe 120 is an exhaust device that guides the gas ejected by the opening of the explosion-proof valve 111. The discharge pipe 120 is fixed to each battery cell 110 via a gasket 1, straddling a plurality of battery cells 110 arranged in a line in the Y direction. The gasket 1 is compressed and sandwiched between the upper surface 110a of each of the arranged battery cells 110 and the discharge pipe 120 when in operation. The discharge pipe 120 is provided with openings 122 (see Figure 5, described later) corresponding to the explosion-proof valve 111 of each battery cell 110. In the discharge pipe 120, a gas discharge passage 123 (see Figure 5, described later) guides the gas flowing in from each opening 122 to the outside. The gas discharge passage 123 is open to the outside space from the outlet 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, where it is discharged to the outside space through the corresponding opening and gas discharge path via the outlet 121.

[0028] As shown in Figures 1-3, the gasket 1 has the same number of flow channels 10 as the explosion-proof valves 111 of each of the battery cells 110 in the battery cell group 101 of the battery module 100, and is arranged in a line corresponding to each of the explosion-proof valves 111 of the battery cells 110. The multiple flow channels 10 are arranged in a line, for example, at equal or approximately equal intervals.

[0029] As shown in Figures 1-3, the flow path section 10 has a cylindrical shape extending along axis x, and defines a flow path 13, which is a space extending along axis x, inside. The axis x extends parallel or approximately parallel to the height direction (Z direction) in the battery module 100. The flow path section 10 has, for example, a cylindrical or approximately cylindrical shape with axis x as the central axis or approximately the central axis. The shape of the flow path section 10 is not limited to a cylindrical shape; for example, the flow passage 10 may be polygonal, and the shape of the cross section perpendicular to axis x of the flow passage 10 is not limited to a circle, but may be elliptical, other circular shapes, polygons, etc. As shown in Figure 4, the flow path section 10 has an upper end face 14 and a lower end face 15, which are a pair of end faces in the direction of axis x, with the upper end face 14 defining an opening 11 and the lower end face 15 defining 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.

[0030] The openings 11 and 12 of the flow path 10 each have a shape corresponding to the explosion-proof valve 111 of the battery cell 110, and for example, a shape that can accommodate the explosion-proof valve 111 inside. 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. If the openings 11 and 12 of the flow path 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's axis in the x direction. However, only one of the openings 11 and 12 of the flow path 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 10 that have a shape corresponding to the explosion-proof valve 111 is the side of the battery cell group 101.

[0031] As shown in Figures 1-3, the base body 20 has a plate-like shape extending in the direction in which the multiple flow channels 10 are aligned. The surface 21 and back surface 22 of the base body 20 extend parallel or substantially parallel to each other, as shown in Figure 3, for example, and are planar or substantially planar, extending along a plane perpendicular to the axis x. Note that the surface 21 and back surface 22 of the base body 20 do not necessarily have to be planar. The surface 21 and back surface 22 may be curved surfaces such as curved or wavy surfaces, or structural surfaces. Note that a structural surface is a surface having a shape corresponding to a predetermined structure, for example, 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.

[0032] As shown in Figure 3, the width of the base body 20 in the axial x direction is greater than the width of the flow channel section 10 in the axial x direction, the surface 21 of the base body 20 is above the upper end surface 14 of the flow channel section 10, and the back surface 22 of the base body 20 is below the lower end surface 15 of the flow channel section 10. The upper side is the side that the surface 21 faces in the axial x direction, and the lower side is the side that 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 channel section 10 and the surface 21 of the base body 20 and the width in the axial x direction between the lower end surface 15 of the flow channel section 10 and the back surface 22 of the base body 20 are the same or approximately the same.

[0033] Furthermore, as shown in Figures 3 and 4, the base body 20 has a flow-hole surface 23 that defines a flow-hole 24, which is a through-hole for housing the flow-through section 10. The flow-hole surface 23 is a cylindrical surface corresponding to the outer peripheral surface 10a, which is the outer peripheral surface of the flow-through section 10, and extends along the axis x. The flow-hole surface 23 extends between the front surface 21 and the back surface 22 of the base body 20, and the flow-through hole 24 penetrates the base body 20 between the front surface 21 and the back surface 22. The flow-hole surface 23 is in contact with the outer peripheral surface 10a of the flow-through section 10, thereby holding the flow-through section 10 in place on the base body 20. The flow-through section 10 is held in place on the base body 20 by, for example, being fitted into the flow-hole surface 23. Alternatively, the flow-through section 10 is held in place on the base body 20 by, for example, being bonded to the flow-through surface 23. Note that the form in which the flow-through section 10 is held in place on the base body 20 may be other forms. As described above, the surface 21 of the base body 20 is above the upper end surface 14 of the flow channel 10, and the back surface 22 of the base body 20 is below the lower end surface 15 of the flow channel 10. For this reason, as shown in Figure 4, the flow hole surface 23 and the flow hole 24 each have an upper flow hole surface 23a and an upper flow hole portion 24a, which are located above the upper end surface 14 of the flow passage 10, and a lower flow hole surface 23b and a lower flow hole portion 24b, which are located below the lower end surface 15 of the flow passage 10.

[0034] The flow-hole surface 23 of the base body 20 has a shape corresponding to the outer circumferential surface of the flow passage 10, and is, for example, a cylindrical surface or a substantially cylindrical surface with axis x as the central axis or substantially the central axis. However, the flow-hole surface 23 of the base body 20 is not limited to a cylindrical surface; for example, the flow-hole surface 23 may be a polygonal cylindrical surface, and the shape of the cross section perpendicular to axis x of the flow-hole surface 23 is not limited to a circle, but may be an ellipse, another circular shape, a polygon, etc. Furthermore, the shape of the upper flow-hole surface 23a of the flow-hole surface 23 may be different from the part of the flow-hole surface 23 that contacts the outer circumferential surface 10a of the flow passage 10 (contact surface 23c), and similarly, the shape of the lower flow-hole surface 23b of the flow-hole surface 23 may be different from the contact surface 23c of the flow-hole surface 23. Furthermore, the shape of the upper flow-hole surface 23a and the shape of the downstream passage surface 23b may be the same, or they may be different in other ways. Furthermore, as shown in Figure 4, the upper crushing allowance d1, which is the width of the upper flow hole surface 23a of the base body 20 in the axial x direction, and the lower crushing allowance d2, which is the width of the lower flow hole surface 23b of the base body 20 in the axial x direction, are the same or approximately the same. However, the upper crushing allowance d1 and the lower crushing allowance d2 may be different from each other.

[0035] The base body 20 has upper flow hole portions 24a and lower flow hole portions 24b formed by the upper flow hole surface 23a and lower flow hole surface 23b as described above. 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 body 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 24a of the base body 20.

[0036] The upper and lower flow holes 23a and 23b of the base body 20 each have a shape corresponding to the explosion-proof valve 111 of the battery cell 110, and for example, a shape that can accommodate the explosion-proof valve 111 inside. Specifically, for example, the diameters of the upper and lower flow holes 23a and 23b 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. If the upper and lower flow holes 23a and 23b of the base body 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's axis in the x direction. However, only one of the upper or lower flow holes 23a and 23b of the base body 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 a shape corresponding to the explosion-proof valve 111 that has an upper flow hole 23a or a lower flow hole 23b becomes the side of the battery cell group 101.

[0037] As described above, the hardness of the base body 20 is lower than that of the flow path section 10. Specifically, the base body 20 is a low-hardness component. For example, although the base body 20 is low-hardness, it has enough hardness to maintain its shape in a natural state without external force. Also, for example, the base body 20 has enough hardness to generate a reaction force when compressed. Specifically, in the usage state of the gasket 1, when the base body 20 is compressed between the upper surfaces of the multiple battery cells 110 of the battery cell group 101 and the discharge pipe 120, it has enough hardness to generate a reaction force on the upper surfaces of the multiple battery cells 110 and the discharge pipe 120, respectively. Also, for example, the base body 20 has enough hardness to deform under the pressure of the gas released from the sealed object, i.e., the explosion-proof valve 111.

[0038] Specifically, for example, the base body 20 is a low-hardness component that has hardness sufficient to maintain its shape in a natural state without external force, hardness sufficient to generate a reaction force when compressed in use, and hardness sufficient to deform under the pressure of gas released from the explosion-proof valve 111. However, the form of the base body 20 is not limited to having such hardness.

[0039] Furthermore, the hardness of the base body 20 is such that it deforms in accordance with the shape of the object to which it is attached during the assembly of the battery module 100. Specifically, the hardness of the base body 20 is such that, during the assembly of the battery module 100, when the gasket 1 is attached to the upper surfaces 110a of the multiple battery cells 110 of the battery cell group 101, and when the gasket 1 is attached to the discharge pipe 120, the base body 10 deforms in accordance with the shape of the upper surfaces 110a of the multiple battery cells 110, and the base body 10 deforms in accordance with the shape of the discharge pipe 120. Note that when the gasket 1 is attached to the upper surfaces 110a of the multiple battery cells 110 of the battery cell group 101, the base body 10 may be pressed against the upper surfaces 110a of the multiple battery cells 110, or against the discharge pipe 120, for example, by the force of a worker or the force of an assembly machine. Furthermore, the deformation of the base body 10 corresponding to the shape of the upper surfaces 110a of the multiple battery cells 110 when the gasket 1 is installed as described above does not have to be such that the base body 10 perfectly corresponds to the shape of the upper surfaces 110a of the multiple battery cells 110. For example, this deformation of the base body 10 may be such that a part of the base body 10 contacts a part of the upper surfaces 110a of the multiple battery cells 110, or a part of the base body 10 makes lockable contact with a part of the upper surfaces 110a of the multiple battery cells 110. Similarly, the deformation of the base body 10 corresponding to the shape of the discharge pipe 120 when the gasket 1 is installed as described above does not have to be such that the base body 10 perfectly corresponds to the shape of the discharge pipe 120. For example, this deformation of the base body 10 may be such that a part of the base body 10 contacts a part of the discharge pipe 120, or a part of the base body 10 makes lockable contact with a part of the discharge pipe 120.

[0040] The base material 20 is made of, for example, low-hardness urethane having the hardness described above. However, the material of the base material 20 is not limited to urethane. The material of the base material 20 may be other elastic materials, for example, low-hardness rubber or other elastomers having the hardness described above. The material of the base material 20 is adjusted, for example, by adjusting the mixing ratio of its constituent components so that the hardness of the base material 20 becomes the desired low hardness described above. For example, if the material of the base material 20 is urethane, the mixing ratio of the isocyanate component is adjusted so that the hardness of the base material 20 becomes the desired hardness.

[0041] Furthermore, the flow channel section 10 has heat resistance and is made of a heat-resistant material. For example, the flow channel section 10 has heat resistance 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 heat resistance of the flow channel section 10 is, for example, heat resistance to 400°C or higher. The material of the flow channel section 10 is, for example, PTFE (polytetrafluoroethylene). The material of the flow channel section 10 may be other materials with the heat resistance described above. Also, the hardness of the flow channel section 10 is higher than the hardness of the base body 20, for example, the hardness of the base body 20 is such that it does not deform even when subjected to the pressure of the gas released from the explosion-proof valve 111.

[0042] Furthermore, the base 20 may be adhesive. The adhesiveness of the base 20 is such that, for example, it is sufficient to fix the base 20 against the force based on the weight of the gasket 1. Specifically, the adhesiveness of the base 20 is such that, when the base 20 is attached to the upper surfaces 110a of the multiple battery cells 110 of the battery cell group 101 or when the base 20 is attached to the discharge pipe 120 during the assembly of the battery module 100, the base 20 will not detach from the upper surfaces 110a of the multiple battery cells 110 or the discharge pipe 120 due to the adhesiveness of the base 20, even if the orientation of the battery cell group 101 or the discharge pipe 120 is changed, such as 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 it does not detach from the battery cell group 101 or the discharge pipe 120 even when subjected to external forces that are not of a magnitude intended to remove the base 20, such as unintentional contact with the base 20 by an worker or the like.

[0043] The degree of adhesion of the base 20 is adjusted, for example, according to the required degree of adhesion. Specifically, for example, when the base 20 is attached to the upper surfaces 110a of the battery cells 110 of the battery cell group 101, or when the base 20 is attached to the discharge pipe 120 during the assembly of the battery module 100, the degree of adhesion of the base 20 is adjusted based on the size of the contact area in which the base 20 contacts the upper surfaces 110a of the battery cells 110 or the discharge pipe 120. For example, if the contact area in which the base 20 contacts the upper surfaces 110a of the battery cells 110 or the discharge pipe 120 is large, the degree of adhesion of the base 20 may be low. This is because if the contact area in which the base 20 contacts the upper surfaces 110a of the battery cells 110 or the discharge pipe 20 is large, the adhesive area is large, so even if the adhesion is low, the base 20 can be prevented from separating from the battery cell group 101 or the discharge pipe 120. On the other hand, if the contact area between the base 20 and the upper surfaces 110a of the multiple battery cells 110 or the discharge pipe 120 is small, the adhesive area is small, so it is preferable for the base 20 to have a greater degree of adhesiveness. Thus, for example, the degree of adhesiveness of the base 20 is adjusted to a size corresponding to the size of the contact area between the base 20 and the object to which it is attached, for example, to a size proportional to the size of the contact area between the base 20 and the object to which it is attached.

[0044] The degree of tackiness of the substrate 20 can be adjusted, for example, by adjusting the material of the substrate 20. For example, if the material of the substrate 20 is urethane, the lower the hardness of the substrate 20, the greater the tackiness; therefore, the degree of tackiness of the substrate 20 can be adjusted by adjusting the blending ratio of the isocyanate component.

[0045] Next, the operation of the gasket 1 having the above-described configuration will be explained. Figure 5 is a partial cross-sectional view of the battery module 100 showing a cross-section of the gasket 1 in use when attached to the battery module 100.

[0046] As shown in Figure 5, in operation, the gasket 1 is sandwiched between the battery cell group 101 and the discharge pipe 120, sealing 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 is in contact with the surface 120a of the discharge pipe 120, and the back surface 22 of the base 20 of the gasket 1 is in contact with 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 valves 111 are surrounded by the lower flow-hole surface 23b of each flow-hole surface 23 of the base 20, and the openings 122 of the discharge pipe 120 are surrounded by the upper flow-hole surface 23a of each flow-hole surface 23 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 in 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 discharge 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 discharge pipe 120 through the flow holes 24 without leakage.

[0047] As shown in Figure 5, in the operating state, the base body 20 is compressed in the axial x direction, shrinking by, for example, the width of the upper crushing allowance d1 and the lower crushing allowance d2 (see Figure 4). As a result, the upper end surface 14 and the lower end surface 15 of the flow section 10 are in contact with the surface 120a of the discharge pipe 120 and the upper surface 110a of the corresponding battery cell 110. Therefore, as shown in Figure 5, in the operating state, all or almost all of the flow hole surface 23 of the base body 20 of the gasket 1 is covered by the flow section 10. Note that in the operating state, the base body 20 compressed in the axial x direction may shrink by a width smaller than the width of the upper crushing allowance d1 and the lower crushing allowance d2 (see Figure 4). In this case, only the upper end surface 14 of the flow section 10 does not come into contact with the surface 120a of the discharge pipe 120, only the lower end surface 15 of the flow section 10 does not come into contact with 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 section 10 do not come into contact with 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 operating state, there is a portion of either or both of the upper flow hole surface 23a and the lower flow hole surface 23b of the flow hole surface 23 of the gasket base 20 that is not covered by the flow section 10.

[0048] Furthermore, as shown in Figure 5, in the operating state, the upper end surface 14 of each flow path section 10 is surrounded by the corresponding opening 122 of the discharge pipe 120, and the lower end surface 15 of each flow path section 10 is surrounded by the corresponding explosion-proof valve 111. Note that in the operating state, the upper end surface 14 of each flow path section 10 does not necessarily have to surround the corresponding opening 122 of the discharge pipe 120, and when viewed in the axial x direction, part or all of the upper end surface 14 of each flow path section 10 may be inside the corresponding opening 122 of the discharge pipe 120.

[0049] As described above, the flow-hole surfaces 23 defining each flow-hole 24 of the base body 20 are covered by heat-resistant flow-hole sections 10, so that the high-temperature, high-pressure gas released from the explosion-proof valve 111 does not come into direct contact with the flow-hole surfaces 23 defining each flow-hole 24 of the base body 20. However, if the flow-hole surfaces 23 defining each flow-hole 24 of the base body 20 are not completely covered by the heat-resistant flow-hole sections 10, the flow-hole surfaces 23 defining each flow-hole 24 of the base body 20 may be slightly exposed to the high-temperature, high-pressure gas released from the explosion-proof valve 111.

[0050] As described above, the base 20 has low hardness. Therefore, the base 20 easily conforms to the shape of the mounting surface of the battery cell group 101, the upper surface 110a of the battery cell 110, and the surface 120a of the discharge pipe 120, with which the base 20 makes contact. For this reason, the base 20 is easy to attach to the mounting object to which the gasket 1 is attached, and the gasket 1 is easy to attach to the mounting object. Thus, the base 20 has high conformability to the object with which it makes contact. For this reason, the gasket 1 can be easily assembled to the mounting object.

[0051] Furthermore, the base 20 is adhesive. As a result, the base 20 adheres to the mounting surface of the battery cell group 101, the upper surface 110a of the battery cell 110, and the surface 120a of the discharge pipe 120, with which the base 20 makes contact. Therefore, the base 20 is easy to attach to the mounting object to which the gasket 1 is attached, and the gasket 1 is easy to attach to the mounting object. In this respect as well, the gasket 1 can be easily assembled to the mounting object.

[0052] Furthermore, because the base body 20 has low hardness, when the flow-hole surface 23 of the base body 20 is exposed to high-pressure gas released from the explosion-proof valve 111, the flow-hole surface 23 deforms, and consequently the base body 20 deforms. When the base body 20 deforms, the sealing performance of the gasket 1 decreases. However, in the gasket 1, the flow-hole surface 23 of the base body 20 is covered by a flow-flow section 10 with high hardness, and the high-pressure gas released from the explosion-proof valve 111 does not directly come into contact with the flow-hole surface 23 of the base body 20. In this way, the flow-hole surface 23 of the base body 20 is protected from the high-pressure gas released from the explosion-proof valve 111 by the flow-flow section 10, which has higher hardness and pressure resistance than the base body 20, and deformation of the flow-hole surface 23 due to the high-pressure gas released from the explosion-proof valve 111 is prevented or suppressed. Therefore, in gasket 1, the hardness of the base 20 can be lowered to improve ease of installation, and even if the base 20 has such low hardness that it deforms under the pressure of the gas released from the explosion-proof valve 111, deformation of the flow-through surface 23 due to the high-pressure gas released from the explosion-proof valve 111 is prevented or suppressed. In this way, gasket 1 has excellent pressure resistance.

[0053] Furthermore, the flow path section 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 23 of the base body 20 is blocked or reduced by the flow path section 10. As a result, the base body 20 will not melt due to the high-temperature gas released from the explosion-proof valve 111, or melting due to the high-temperature gas released from the explosion-proof valve 111 is suppressed. Thus, the gasket 1 has excellent heat resistance.

[0054] As mentioned above, even if the flow-hole surface 23 of the base body 20 is not completely covered by the flow-through section 10, the amount of high-pressure gas released from the explosion-proof valve 111 in contact with the flow-hole surface 23 of the base body 20 can be reduced. Therefore, even with a flow-through section 10 that does not completely cover the flow-hole surface 23 of the base body 20, deformation of the flow-hole surface 23 due to high-pressure gas released from the explosion-proof valve 111 can be suppressed. For this reason, even in this case, the gasket 1 has excellent pressure resistance.

[0055] Furthermore, even if the flow-hole surface 23 of the base body 20 is not completely covered by the flow channel section 10, the amount of high-temperature gas released from the explosion-proof valve 111 in contact with the flow-hole surface 23 of the base body 20 can be reduced. Therefore, even with a flow channel section 1 that does not completely cover the flow-hole surface 23 of the base body 20, melting of the flow-hole surface 23 due to high-temperature gas released from the explosion-proof valve 111 can be suppressed. For this reason, even in this case, the gasket 1 has excellent heat resistance.

[0056] As described above, the gasket 1 according to the first embodiment of the present invention can be made highly conformable to the object it contacts, and can have excellent heat resistance and pressure resistance.

[0057] In the gasket 1 described above, the inner circumferential surface 10b of the flow channel portion 10 is assumed to be entirely exposed to the flow channel hole 24. However, the inner circumferential surface 10b of the flow channel portion 10 may be covered by the base body 20. For example, as shown in Figure 6, the flow channel portion 10 may be embedded in the base body 20. In this case, the gasket 1 can be easily manufactured by insert molding. Figure 6 shows a cross-section corresponding to Figure 4. In this case, one or both of the upper end surface 14 and the lower end surface 15 of the flow channel portion 10 may be exposed from the base body 20. Also, a part of the inner circumferential surface 10b of the flow channel portion 10 may be covered by the base body 20.

[0058] Next, a gasket 2 according to a second embodiment of the present invention will be described. The gasket 2 according to the second embodiment of the present invention differs from the gasket 1 described above in the configuration of its base, and has a base 30 that is different from the base 20. Hereinafter, for the gasket 2, components that have the same or similar functions as the gasket 1 described above will be denoted by the same reference numerals and their descriptions will be omitted, while the different components will be described.

[0059] Figure 7 is a plan view of gasket 2 according to a second embodiment of the present invention. As described above, the base body 20 of gasket 1 is solid between two adjacent flow-hole surfaces 23, and the base body 20 material is filled in between. On the other hand, as shown in Figure 7, in the base body 30 of gasket 2, the space between two adjacent flow-hole surfaces 23 is not solid, and a weight-reducing portion 31, which is a recessed area (recess) in the axial x direction, is formed between the two adjacent flow-hole surfaces 23. The weight-reducing portion 31 is a through-hole that penetrates between the surface 21 and the back surface 22, for example, as shown in Figure 7.

[0060] Furthermore, as shown in Figure 7, the base body 30 has a circumferential wall portion 32 extending in the axial x direction around the flow hole 24, formed by the weight-reducing portion 31. The circumferential wall portion 32 defines a part of the flow hole surface 23 and has thickness toward the outer circumference from the flow hole surface 23. Also, as shown in Figure 7, the base body 30 has a pair of side wall portions 33 and 34 formed by the weight-reducing portion 31, which extend in the direction of the arrangement of the flow channel portion 10. The side wall portion 33 and the side wall portion 34 face each other via the circumferential wall portion 32 and are integrally connected to the circumferential wall portion 32. The side wall portion 33 and the side wall portion 34 each define a part of the flow hole surface 23.

[0061] In gasket 2, as described above, a weight-reducing portion 31 is formed in the base body 30. Therefore, when the base body 30 is compressed during use of gasket 2, the peripheral wall portion 32 and the side wall portions 33 and 34 can deform toward the weight-reducing portion 31. As a result, during use, it is possible to suppress the filling rate of the base body 30 from increasing beyond an acceptable range that would cause damage to the base body 30. On the other hand, it is possible to ensure airtightness between the base body 30 and the battery cell group 101 and the discharge pipe 120.

[0062] As described above, the shape of the hollowed-out portion 31 is adjusted, for example, and the thickness 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 body 30 is a desired value and the base body 30 has the desired sealing performance.

[0063] Furthermore, the weight-reducing portion 31 is not limited to penetrating the base body 30 as described above. For example, as shown in Figure 8, the weight-reducing portion 31 may be recessed from the surface 21 and not penetrate the back surface 22. Also, as shown in Figure 9, the weight-reducing portion 31 may be recessed from the back surface 22 and not penetrate the surface 21. Note that Figures 8 and 9 show cross-sections corresponding to the cross-section along line BB in Figure 7.

[0064] Furthermore, the base 30 does not necessarily have to have weight-reducing sections 31 between every pair of adjacent flow-through hole surfaces 23, and there may be areas between two adjacent flow-through holes 22 where weight-reducing sections 24 are not provided.

[0065] Furthermore, gasket 2 performs the same function as gasket 1 described above. Thus, according to the gasket 2 of the second embodiment of the present invention, it is possible to achieve high conformability to the object it contacts and excellent heat resistance and pressure resistance.

[0066] Although the present invention has been described above through the embodiments described above, the technical scope of the present invention is not limited to the scope described in the embodiments above. It will be obvious to those skilled in the art that various modifications or improvements can be made to the embodiments described above. It will be clear from the claims that such modified or improved forms may also be included in the technical scope of the present invention.

[0067] The embodiments described above are for the purpose of facilitating understanding of the present invention and are not intended to limit its interpretation. Furthermore, the embodiments described above do not limit the scope of application of the present invention, and the present invention may encompass anything as its target application. The components of the above embodiments, as well as their arrangement, materials, conditions, shapes, and sizes, are not limited to those exemplified and can be modified as appropriate. For example, the present invention includes differences that arise in the implementation of manufacturing tolerances, etc. Furthermore, components shown in different embodiments can be partially substituted or combined to the extent that they do not contradict each other in a technical sense. In addition, each configuration can be selectively combined as appropriate to achieve at least some of the problems and effects described above. [Explanation of symbols]

[0068] 1,2 Gasket, 10 Flow channel, 10a Outer surface, 10b Inner surface, 11,12 Opening, 13 Flow channel, 14 Upper end surface, 15 Lower end surface, 20,30 Base body, 21 Surface, 22 Back surface, 23 Flow hole surface, 23a Upper flow hole surface, 23b Lower flow hole surface, 23c Contact surface, 24 Flow hole, 24a Upper flow hole section, 24b Lower flow hole section, 31 Weight reduction section, 32 Peripheral wall section, 33,34 Side wall section, 100 Battery module, 101 Battery cell group, 110 Battery cell, 110a Top surface, 111 Explosion-proof valve, 112 Electrode, 120 Discharge pipe, 120a Surface, 121 Discharge port, 122 Opening, 123 Gas discharge passage, d1,d2 Compression allowance, x axis line

Claims

1. A gasket for sealing an object between two members, A flow channel section is a cylindrical member having multiple pairs of openings, A base having a pair of faces opposite each other, The substrate has elasticity, The flow channel portion is held in the base such that the pair of openings are each open from the pair of surfaces of the base so as to form a flow channel for the object to be sealed. The hardness of the substrate is lower than the hardness of the flow channel. gasket.

2. The substrate has a hardness that allows it to maintain its shape in a natural state without being subjected to external forces. The gasket according to claim 1.

3. The substrate has a hardness that generates a reaction force when compressed between the two members. The gasket according to claim 2.

4. The substrate has a hardness that allows it to deform under pressure from the object to be sealed. The gasket according to claim 1.

5. The substrate is formed from a low-hardness material. The aforementioned low-hardness material includes rubber, urethane, and elastomer. The gasket according to claim 1.

6. The aforementioned flow channel is formed of a heat-resistant material. The gasket according to claim 1.

7. The heat resistance of the aforementioned flow channel is its heat resistance to the temperature of the object being sealed. The gasket according to claim 6.

8. The aforementioned material is PTFE. The gasket according to claim 6.

9. The substrate is adhesive. The gasket according to claim 1.

10. The adhesiveness of the substrate is such that it is able to fix the substrate against the force based on the weight of the gasket. The gasket according to claim 9.

11. The substrate has a recess between two adjacent flow channels, The recess is recessed in the direction that the pair of surfaces of the base body face. The gasket according to claim 1.

12. One of the two components 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 the gas released from each of the explosion-proof valves of the plurality of battery cells. The object to be sealed is the gas released from the plurality of explosion-proof valves, Each of the aforementioned multiple flow channels forms a flow path for the gas released from the aforementioned multiple explosion-proof valves. The gasket according to claim 1.

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