Gasket

Abstract

A gasket (10) seals, in a cell (100) of a water electrolysis device, a space (S1) between a separator (101) and an electrolyte membrane (104) of a membrane assembly (103), and a space (S2) between a separator (102) and the electrolyte membrane (104). This gasket (10) comprises: a seal side surface (11) and a contact side surface (12) that face away from each other; a plurality of through-holes (13) that pass through between the seal side surface (11) and the contact side surface (12); a first seal section (14) that is formed on the seal side surface (11) and that is for sealing the space (S1) or the space (S2); and a plurality of second seal sections (15) that are formed on the seal side surface (11) farther on the outer peripheral side than the first seal section (14) and that respectively surround the plurality of through-holes (13). The gasket (10) is configured such that the reaction force F increases when the crushing margin C between the separators (101, 102) reaches or exceeds a predetermined value.

Description

Gasket

[0001] The present invention relates to a gasket.

[0002] Gaskets are provided in each cell of a water electrolysis device or a fuel cell. The gasket is formed of an elastic material and is compressed between the anode-side separator and the cathode-side separator and the electrolyte membrane, respectively, to seal the space between each separator and the electrolyte membrane, prevent leakage of fluid in the space inside these cells, and also prevent mixing of fluids in each space (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2012-117140

[0004] When assembling a water electrolysis device or a fuel cell, in each cell, the gasket is tightened and compressed between the separators. If the gasket is over-compressed, the filling rate of the gasket becomes excessive, and the gasket may be damaged. Therefore, in the cell tightening process, in order to prevent the gasket from being in an over-compressed state, the crushing allowance of the gasket is managed by controlling the tightening load and the distance between the separators.

[0005] For this reason, there is a need for a configuration that can prevent the gasket from being over-compressed in the cell tightening process for conventional gaskets.

[0006] The present invention has been made in view of the above problems, and an object thereof is to provide a gasket that can suppress over-compression in a cell.

[0007] To achieve the above objective, the gasket according to the present invention is a gasket for sealing the space between each of a pair of opposing members and an intermediate member facing each of the pair of members in the opposing direction, wherein the gasket is formed in an annular shape from an elastic material, and one of the gaskets is placed on top of the other gasket inverted to seal the space, and comprises a pair of annular surfaces facing each other, namely a sealing side and a contact side, a plurality of through holes penetrating between the sealing side and the contact side, a first sealing portion formed on the sealing side for sealing the space, and a plurality of second sealing portions formed on the sealing side on the outer circumference of the first sealing portion, surrounding each of the plurality of through holes, wherein the reaction force increases when the compression allowance between the pair of members exceeds a predetermined value.

[0008] In one aspect of the present invention, when the compression allowance exceeds a predetermined value, the rate of increase of the reaction force with respect to the compression allowance increases.

[0009] In a gasket according to one aspect of the present invention, the sealing surface faces one or the other of the pair of members, and the other portion of the sealing surface comes into contact with one or the other of the pair of members when the compression amount exceeds a predetermined value.

[0010] A gasket according to one aspect of the present invention further comprises at least one projection formed on the sealing side surface, wherein the projection contacts one or the other of the pair of opposing members when the compression amount exceeds a predetermined value.

[0011] In a gasket according to one aspect of the present invention, the first sealing portion has at least one annular bead, and the second sealing portion has at least one annular bead, wherein the height of the projection from the sealing side surface is lower than the height of the bead of the first sealing portion and the bead of the second sealing portion from the sealing side surface.

[0012] In a gasket according to one aspect of the present invention, the projection extends along the first sealing portion.

[0013] In a gasket according to one aspect of the present invention, the projection is located on the outer circumference side of the first sealing portion.

[0014] In a gasket according to one aspect of the present invention, the projection is aligned with the plurality of through holes in the circumferential direction.

[0015] A gasket according to one aspect of the present invention comprises four through holes and two projections, two of the four through holes being adjacent to each other, one of the two projections being located in the circumferential space between one of the two adjacent through holes and the other of the two adjacent through holes, and the other projection being located in the circumferential space between one of the two adjacent through holes and the other of the two adjacent through holes.

[0016] In a gasket according to one aspect of the present invention, the pair of members are separators for a cell of a water electrolysis device or fuel cell, and the intermediate member is the electrolyte membrane of the cell.

[0017] To achieve the above objective, the gasket according to the present invention is a gasket for sealing the space between each of a pair of opposing members and an intermediate member facing each of the pair of members in the opposing direction, wherein the gasket is formed in an annular shape from an elastic material, and one of the gaskets is placed on top of the other gasket in the same orientation to seal the space, and comprises a pair of annular surfaces facing each other, namely a sealing side and a contact side, a plurality of through holes penetrating between the sealing side and the contact side, a first sealing portion formed on the sealing side for sealing the space, and a plurality of second sealing portions formed on the sealing side on the outer circumference of the first sealing portion, surrounding each of the plurality of through holes, wherein the reaction force increases when the compression allowance between the pair of members exceeds a predetermined value.

[0018] According to the gasket of the present invention, it is possible to suppress overcompression in the cell.

[0019] This is a front view of a gasket according to an embodiment of the present invention. This is a rear view of a gasket according to an embodiment of the present invention. This is a cross-sectional view along line A-A in Figure 1. This is a partial cross-sectional view showing a schematic of a water electrolysis apparatus equipped with a gasket according to an embodiment of the present invention. This is a cross-sectional view showing the gasket in a usage state with a tightening load applied. This is a front view of the gasket apparatus. This is a cross-sectional view showing a cross-section along line D-D in Figure 6. This is a graph showing the relationship between the reaction force F of the gasket and the gap amount G between the separators. This is a partial cross-sectional view showing a schematic of a water electrolysis apparatus equipped with a modified example of the gasket apparatus according to an embodiment of the present invention.

[0020] Embodiments of the present invention will be described below with reference to the drawings. In the drawings, not all of the components are assigned reference numerals, and some of the reference numerals for components may be omitted.

[0021] The gasket according to the present invention is a gasket for sealing the space between each of a pair of opposing members and an intermediate member that is opposite each of the pair of members in the opposing direction. These opposing pairs of members and intermediate members are, for example, a pair of separators and an electrolyte membrane used in cells such as water electrolysis devices and fuel cells of hydrogen generators. As an example, the gasket according to an embodiment of the present invention is for sealing the space between each of a pair of opposing separators and an electrolyte membrane in a cell of a water electrolysis device. However, the application of the gasket according to the present invention is not limited to this and includes other applications.

[0022] Figure 1 is a front view of a gasket 10 according to an embodiment of the present invention, Figure 2 is a rear view of the gasket 10, and Figure 3 is a cross-sectional view along line A-A in Figure 1. Figures 4 and 5 are schematic partial cross-sectional views of a water electrolysis apparatus 1 equipped with the gasket 10. The water electrolysis apparatus 1 is equipped with the gasket 10. As shown in Figures 4 and 5, the gasket 10 is used by overlapping one gasket 10 with the other gasket 10 in an inverted manner. As shown in Figures 4 and 5, the gasket 10 seals the space S1 between one separator 101 of a pair of separators and the electrolyte membrane 104 of the membrane assembly 103, which is an intermediate member, and the space S2 between the other separator 102 of the pair of separators and the electrolyte membrane 104 in the cell 100 of the water electrolysis apparatus 1. As shown in Figures 1 to 3, the gasket 10 comprises a pair of annular surfaces facing away from each other, namely a sealing surface 11 and a contact surface 12; a plurality of through holes 13 (13a, 13b, 13c, 13d) penetrating between the sealing surface 11 and the contact surface 12; a first sealing portion 14 formed on the sealing surface 11 for sealing the space S1 or space S2; and a plurality of second sealing portions 15 formed on the sealing surface 11 on the outer circumference of the first sealing portion 14, surrounding each of the plurality of through holes 13. The gasket 10 is configured such that the reaction force F increases when the compression allowance C between the pair of separators 101 and 102 exceeds a predetermined value. The configuration of the gasket 10 will be described in detail below.

[0023] As shown in Figures 1 to 3, the first seal portion 14 has, for example, an annular inner seal portion 16 and an annular outer seal portion 17. The inner seal portion 16 is located on the inner circumference side of the outer seal portion 17, and the outer seal portion 17 surrounds the inner seal portion 16 from the outer circumference side.

[0024] As shown in Figures 1 to 3, the inner seal portion 16 has, for example, an annular inner seal surface 16a formed on the contact side surface 12. When one gasket 10 is placed on top of the other gasket 10 inverted, the inner seal surface 16a of the gasket 10 faces the inner seal surface 16a of the other gasket 10 in the inverted direction, forming a accommodating space 30, which is an annular gap open to the inner circumference, as shown in Figures 4 and 5. The accommodating space 30 can accommodate the outer peripheral end of the electrolyte membrane 104. The inner seal portion 16 also has, for example, one or more beads 16b formed on the seal side surface 11. The beads 16b face away from the inner seal surface 16a in the inverted direction. The inverted direction is the direction of the other gasket 10 relative to the gasket 10 in the two combined gaskets 10, and the direction in which the gasket 10 faces the other gasket 10.

[0025] The gasket 10 has, for example, four through holes 13 (13a, 13b, 13c, 13d), with two of the four through holes 13 (through holes 13a, 13b) being adjacent and the other two of the four through holes 13 (through holes 13c, 13d) being adjacent. When another gasket 10 is placed on top of gasket 10 inverted, one of the pair of through holes 13 of gasket 10 overlaps with the other of the pair of through holes 13 of the other gasket 10 in the direction of inversion. Each of the through holes 13 is included in the flow path 3 of the water electrolysis apparatus 1. The flow path 3 is a flow path for the electrolyte and products generated from the electrolyte.

[0026] The second seal portion 15 is configured to seal the flow path 3, which includes each of the through holes 13, between the separators 101 and 102 in the cell 100 (see Figure 4). As shown in Figures 1 and 2, the second seal portion 15 has, for example, a sealing surface 15a formed on the contact side surface 12. The sealing surface 15a is configured such that when one gasket 10 is placed on top of another gasket 10 in an inverted position, the sealing surface 15a of gasket 10 contacts the sealing surface 15a of the other gasket 10 in the inverted direction. The second seal portion 15 also has, for example, one or more beads 15b formed on the sealing side surface 11. The beads 15b face away from the sealing surface 15a in the inverted direction.

[0027] As described above, the gasket 10 is designed so that when the compression allowance C between the separators 101 and 102 exceeds a predetermined value, the reaction force F increases. In other words, in the water electrolysis apparatus 1, the gasket 10 is sandwiched between the separators 101 and 102 and compressed by a compression allowance C, generating a reaction force F against the separators 101 and 102. When this compression allowance C exceeds a predetermined value, the reaction force F of the gasket 10 increases. For example, in cell 100, the sealing side surface 12 of the gasket 10 faces the separator 101 or separator 102, and the other part of the sealing side surface 12 comes into contact with the separator 101 or separator 102 when the compression allowance C exceeds a predetermined value, or when the compression allowance C is near a predetermined value. The compression allowance C is the amount by which the combined gasket 10 is compressed, and is, for example, the distance over which the combined gasket 10 is compressed in the direction in which the separators 101 and 102 in the cell 100 face each other.

[0028] The gasket 10 described above will now be explained in more detail. As shown in Figures 4 to 7, one gasket 10 and the other gasket 10 constitute the gasket assembly 2. Hereafter, one gasket 10 will be referred to as the first gasket 10, and the other gasket 10 as the second gasket 20. Figure 6 is a cross-sectional view of the gasket assembly 2, and Figure 7 is a front view of the gasket assembly 2. Furthermore, Figure 4 corresponds to the cross-section along line B-B in Figure 6, and Figure 6 corresponds to the cross-section along line D-D in Figure 6.

[0029] As shown in Figures 4 and 5, the gasket device 2 is provided in the cell 100 between one separator 101 of the pair of separators and the electrolyte membrane 104 of the intermediate member membrane assembly 103, and between the electrolyte membrane 104 of the other separator 102 of the pair of separators, to seal the space S1 between separator 101 and the electrolyte membrane 104 and the space S2 between separator 102 and the electrolyte membrane 104. As shown in Figures 4 and 5, the gasket device 2 comprises an annular first gasket 10 and an annular second gasket 20. The outer circumferential side of the first gasket 10 (contact surface 18, described later) and the outer circumferential side of the second gasket 20 (contact surface 28, described later) are in contact with each other. When the outer circumference of the first gasket 10 and the outer circumference of the second gasket 20 come into contact, a accommodating space 30, which is an annular gap open to the inner circumference, is formed between the inner circumference of the first gasket 10 (inner sealing surface 16a) and the inner circumference of the second gasket 20 (inner sealing surface 26a, described later). The accommodating space 30 is capable of accommodating the outer circumference end of the electrolyte membrane 104, which is an intermediate member. The configuration of the gasket device 2 will now be described in detail.

[0030] As shown in Figures 4 and 5, in the cell 100 of the water electrolysis apparatus 1, the membrane assembly 103 has an electrolyte membrane 104 and a pair of catalyst layers, an anode catalyst layer 105 which is the anode side electrode and a cathode catalyst layer 106 which is the cathode side electrode, respectively, provided on both sides of the electrolyte membrane 104. The electrolyte membrane 104 is, for example, an ion exchange membrane, and more specifically, a solid polymer electrolyte membrane. Gas diffusion layers 107 and 108 are provided on the surfaces of the anode catalyst layer 105 and the cathode catalyst layer 106, respectively. As shown in Figures 4 and 5, in the cell 100, the internal space of the cell 100 is divided into two spaces S1 and S2 by the electrolyte membrane 104, with an anode chamber S1 formed between the separator 101 and the electrolyte membrane 104, and a cathode chamber S2 formed between the separator 102 and the electrolyte membrane 104. The anode chamber S1 and the cathode chamber S2 are the spaces to be sealed by the gasket device 2. As shown in Figures 4 and 5, the anode chamber S1 is sealed by the first gasket 10, and the cathode chamber S2 is sealed by the second gasket 20. The anode catalyst layer 105 and the gas diffusion layer 107 are located in the anode chamber S1, and the cathode catalyst layer 106 and the gas diffusion layer 108 are located in the cathode chamber S2. The water electrolysis device 1 comprises, for example, a plurality of cells 100, which are stacked. However, the water electrolysis device 1 may be formed by a single cell 100.

[0031] Figure 6 is a front view of the gasket device 2, and Figure 7 is a cross-sectional view showing a cross-section along line D-D in Figure 6. Figures 6 and 7 show the gasket device 2 in an assembled state, with the first gasket 10 and the second gasket 20 assembled. Figures 6 and 7 also show the gasket device 2 in an assembled state without the electrolyte membrane 104 attached. As shown in Figures 6 and 7, the gasket device 2 has an annular shape along a plane. The gasket device 2 is annular or substantially annular, for example, as shown in Figure 6. The shape of the gasket device 2 is not limited to annular, and may be other shapes such as a rectangular annular shape.

[0032] As shown in Figures 6 and 7, the gasket device 2 has, for example, four through holes 4a, 4b, 4c, and 4d. The through holes 4a to 4d each penetrate the first gasket 10 and the second gasket 20. The through holes 4a to 4d are passages for supplying electrolyte to the anode chamber S1 or cathode chamber S2 in the cell 100, or passages for discharging products generated from the anode chamber S1 or cathode chamber S2 to the outside of the cell 100. For example, through hole 4a is a supply passage for supplying electrolyte to the anode chamber S1, and through hole 4b is a supply passage for supplying electrolyte to the cathode chamber S2. Also, through hole 4d is a discharge passage for discharging products generated from the anode chamber S1 to the outside of the cell 100, and through hole 4c is a discharge passage for discharging products generated from the cathode chamber S2 to the outside of the cell 100. The electrolytes supplied through the through holes 4a and 4b may be the same or different. Cell 100 is, for example, an alkaline water electrolysis device, and an alkaline aqueous solution is used as the electrolyte. This alkaline aqueous solution is not limited to any particular type, but for example, a KOH aqueous solution, a NaOH aqueous solution, or K ２ CO ３ Aqueous solution, KHCO ３ Aqueous solution, Na ２ CO ３ Aqueous solution, NaHCO ３ The electrolyte is an aqueous solution, etc. Cell 100 may be, for example, a PEM-type water electrolysis apparatus. In this case, pure water is supplied to the anode chamber S1. The gases generated in the anode chamber S1 and the cathode chamber S2 are oxygen and hydrogen, respectively. The electrolyte may be discharged from the anode chamber S1 and the cathode chamber S2, respectively, through through holes 4c and 4d, along with the products.

[0033] As shown in Figure 7, in the assembled gasket device 2, the outer circumference side of the first gasket 10 (contact surface 18, described later) and the outer circumference side of the second gasket 20 (contact surface 28, described later) are in contact. Note that the assembled gasket device 2 shown in Figure 7 is in a free state, and no external force is applied to the gasket device 2. Furthermore, a housing space 30 is formed between the inner sealing surface 16a of the inner sealing portion 16 of the first sealing portion 14 of the first gasket 10 and the inner sealing surface 26a of the inner sealing portion 26 of the first sealing portion 24 of the second gasket 20, which will be described later, and is open to the inner circumference side. As described above, the outer circumference end 104a of the electrolyte membrane 104 is housed in the housing space 30.

[0034] Next, the configuration of the first gasket 10 will be described. As shown in Figures 1 to 3, 6, and 7, the first gasket 10 has a shape corresponding to the gasket device 2 and has an annular shape along a plane. Specifically, the first gasket 10 has a central axis x, an annular shape along a plane perpendicular to this central axis x, and an annular shape that is symmetric or substantially symmetric with respect to the plane of symmetry P, which is the plane containing this central axis x. Note that the central axis x is a hypothetical line, and the plane of symmetry P is a hypothetical plane. The first gasket 10 is, for example, an annular or substantially annular shape with the central axis x as its central axis, as shown in Figures 1 and 2. Note that the shape of the first gasket 10 is not limited to an annular shape, and may be other shapes such as a rectangular annular shape.

[0035] As shown in Figures 1 to 3, the first gasket 10 is plate-shaped and has a pair of annular surfaces, a sealing side 11 and a contact side 12, which are facing away from each other. The sealing side 11 is the front side, and the contact side 12 is the back side. As shown in Figures 1 to 3, the first gasket 10 has four through holes 13a, 13b, 13c, and 13d, which form the four through holes 4a to 4d of the gasket device 2 described above. The through holes 13a to 13d are the through holes 13 of the gasket 10 described above. The through holes 13a to 13d penetrate between the sealing side 11 and the contact side 12. The through holes 13a and 13b correspond to the through holes 4a and 4b, respectively, and as described above, are openings for supplying electrolyte to the anode chamber S1 and the cathode chamber S2. The through holes 13c and 13d correspond to the through holes 4c and 4d, respectively, and as described above, they are openings for discharging the products generated from the anode chamber S1 and cathode chamber S2 to the outside of the cell 100. For example, as shown in Figures 1 and 2, the supply-side through holes 13a and 13b are provided adjacent to each other in the circumferential direction of the first gasket 10, and the discharge-side through holes 13c and 13d are provided adjacent to each other in the circumferential direction. Also, for example, as shown in Figures 1 and 2, the through holes 13a and 13b are provided such that the positions of the centers of the through holes 13a and 13b are symmetrical or approximately symmetrical with respect to the plane of symmetry P. Similarly, for example, as shown in Figures 1 and 2, the through holes 13c and 13d are provided such that the positions of the centers of the through holes 13c and 13d are symmetrical or approximately symmetrical with respect to the plane of symmetry P. Furthermore, as shown in Figures 1 and 2, for example, the through holes 13a and 13b on the supply side and the through holes 13c and 13d on the discharge side are opposite each other in a direction along the plane of symmetry P.

[0036] Furthermore, for example, when the contour of the through-hole 13a is projected onto a virtual projection plane which is a plane perpendicular to the central axis x, the shape on the projection plane that is rotationally symmetric with respect to the intersection line of the projection plane and the symmetric plane P (the projected contour of the inverted through-hole 13a) is such that the through-holes 13a and 13b are formed so that they overlap with the contour of the through-hole 13b on the projection plane. Similarly, for example, when the contour of the through-hole 13c is projected onto a projection plane, the shape on the projection plane that is rotationally symmetric with respect to the intersection line of the projection plane and the symmetric plane P (the projected contour of the inverted through-hole 13c) is such that the through-holes 13c and 13d are formed so that they overlap with the contour of the through-hole 13d on the projection plane.

[0037] Furthermore, as shown in Figures 1 to 3, the seal side surface 11 is, for example, a surface extending on a plane or a substantially plane. As described above, the seal side surface 11 has a bead 16b of the inner seal portion 16 of the first seal portion 14 and a bead 17b of the outer seal portion 17 of the first seal portion 14. The beads 16b and 17b protrude from the seal side surface 11 toward the front and extend, for example, along a circle or a substantially circle. Also, as shown in Figure 1, the beads 16b and 17b are provided on the inner circumference side of the through holes 13a to 13d. As an example, as shown in Figure 1, the seal side surface 11 has two beads 16b and two beads 17b. The two beads 16b are formed concentrically and their diameters increase sequentially in the radial direction. Similarly, the two beads 17b are formed concentrically and their diameters increase sequentially in the radial direction. For example, as shown in Figure 1, the beads 16b and 17b each form groups, with two beads 16b positioned close to each other, and two beads 17b positioned close to each other. The group of beads 17b is positioned on the outer circumference at a distance from the group of beads 16b. The beads 16b on the inner circumference are positioned facing away from the inner sealing surface 16a of the inner sealing portion 16 of the first sealing portion 14, which defines the containment space 30 for housing the electrolyte membrane 104. On the other hand, the group of beads 17b on the outer circumference are positioned facing away from the contact surface 18, which will be described later.

[0038] As described above, a bead 15b of the second seal portion 15 is formed on the seal side surface 11. The bead 15b is a bead for sealing each of the flow paths 3 in the cell 100. As shown in Figures 1 and 3, the bead 15b protrudes from the seal side surface 11 toward the front. The second seal portion 15 has multiple beads 15b, with a bead 15b for each of the through holes 13a to 13d. For example, as shown in Figure 1, the second seal portion 15 has four beads 15b, and each of the four beads 15b surrounds the through holes 13a to 13d. The second seal portion 15 may have multiple beads 15b for each of the through holes 13a to 13d. In this case, multiple beads 15b surround each of the through holes 13a to 13d, and around each of the through holes 13a to 13d, multiple beads 15b are formed concentrically, with their diameters increasing sequentially in the radial direction.

[0039] The heights from the seal side surface 11 to the tips of the beads 15b, 16b, and 17b are the same or approximately the same. However, the heights from the seal side surface 11 to the tips of the beads 15b, 16b, and 17b do not necessarily have to be the same.

[0040] As shown in Figures 2 and 3, the contact surface 12 has an annular contact surface 18 on its outer circumference and an inner seal surface 16a of the inner seal portion 16 of the first seal portion 14 that forms the housing space 30. The contact surface 18 includes the outer seal surface 17a of the outer seal portion 17 of the first seal portion 14 and the seal surface 15a of the second seal portion 15. The contact surface 18 is the outer circumference portion of the first gasket 10, and the inner seal surface 16a is the inner circumference portion of the first gasket 10. As shown in Figures 2 and 3, the inner seal surface 16a is provided on the inner circumference side of the contact surface 18, extends further toward the seal surface 11 than the contact surface 18, and forms a stepped portion 14a on the inner circumference side of the contact surface 18 that is recessed toward the seal surface 11. The stepped portion 14a constitutes the housing space 30 of the gasket device 2.

[0041] As shown in FIGS. 2 and 3, the contact surface 18 is a portion on the outer peripheral side of the step portion 14a of the contact side surface 12, and is, for example, a surface extending on a flat surface or a substantially flat surface. Further, the contact surface 18 is a surface extending annularly and has an annular shape corresponding to the shape of the contact side surface 12, and is, for example, an annular shape or a substantially annular shape having an unevenness. The through holes 13a to 13b open to the contact surface 18. Further, the step portion 14a is a portion on the inner peripheral side of the contact side surface 12 that spreads inward from the inner peripheral side end of the contact surface 18 as shown in FIGS. 2 and 3.

[0042] The inner seal surface 16a forming the step portion 14a is a surface that contacts the electrolyte membrane 104 housed in the housing space 30 in the gasket device 2, and is also a surface that seals between the electrolyte membrane 104 in the cell 100. As shown in FIGS. 2 and 3, the inner seal surface 16a is, for example, a surface extending on a flat surface or a substantially flat surface. Further, the inner seal surface 16a is a surface extending annularly and has an annular shape corresponding to the shape of the contact side surface 12, and is, for example, an annular shape or a substantially annular shape having an unevenness. Further, the step portion 14a is a portion on the inner peripheral side of the contact side surface 12 that spreads inward from the inner peripheral side end of the contact surface 18 as shown in FIGS. 2 and 3.

[0043] As described above, in the gasket 10, when the crush allowance C of the other portion of the seal side surface 11 becomes a predetermined value or more, it comes into contact with the separator 101 or the separator 102, and in the first gasket 10, when the crush allowance C of the other portion of the seal side surface 11 becomes a predetermined value or more, it comes into contact with the separator 101. Specifically, for example, as shown in FIGS. 1 and 3, the first gasket 10 further includes at least one protrusion 19 formed on the seal side surface 11. When the crush allowance C becomes a predetermined value or more, the protrusion 19 comes into contact with the opposing separator 101.

[0044] Specifically, as shown in FIG. 3, the height h1 of the protrusion 19 from the seal side surface 11 is lower than the height h2 of the inner bead 16b of the first seal portion 14, the height h3 of the outer bead 17b of the first seal portion 14, and the height h4 of the bead 15b of the second seal portion 15. As shown in FIG. 1, the height h1 of the protrusion 19 is the distance between the seal side surface 11 and the tip 19a of the protrusion 19 in the direction of inversion. The tip 19a of the protrusion 19 is the portion of the protrusion 19 that is located on the most front side in the direction of inversion. The tip 19a extends along a plane or a substantially plane, for example, as shown in FIG. 3, and specifically, it extends parallel or substantially parallel to the contact surface 18. Also, the height h2 of the inner bead 16b, the height h3 of the outer bead 17b, and the height h4 of the bead 15b are the heights from these seal side surfaces 11, and are respectively the distances between the tip of the inner bead 16b and the seal side surface 11, the distance between the tip of the outer bead 17b and the seal side surface 11, and the distance between the tip of the bead 15b and the seal side surface 11 in the direction of inversion. The tips of the inner bead 16b, the outer bead 17b, and the bead 15b are respectively the portions of the inner bead 16b, the outer bead 17b, and the bead 15b that are located on the most front side in the direction of inversion.

[0045] The protrusions 19 are preferably arranged uniformly in the circumferential direction of the first gasket 10, that is, in the circumferential direction around the central axis x. Also, the protrusions 19 are preferably formed so as to occupy a large range in the range where the beads 15b, 16b, 17b are not formed on the seal side surface 11. Also, the protrusions 19 are preferably formed to be symmetric with respect to the symmetry plane P. This is because in the usage state of the first gasket 10 described later, when the protrusions 19 contact the separator 101, it is preferable that the reaction forces of the beads 15b, 16b, 17b are uniform throughout. Specifically, for example, when the protrusions 19 contact the separator 101, it is preferable that the posture of the gasket 10 is stable.

[0046] As shown in Figures 1 and 3, the projection 19 extends, for example, along the beads 16b and 17b of the first seal portion 14. Furthermore, the projection 19 is located, for example, on the outer circumference side of the beads 16b and 17b. Also, the projection 19 is aligned, for example, with a plurality of through holes 13a to 13d in the circumferential direction. Specifically, for example, as shown in Figure 1, the first gasket 10 has two projections 19. In this case, for example, one of the two projections 19 is provided in one of the circumferential spaces between two adjacent through holes 13a and 13b and two adjacent through holes 13c and 13d, and the other projection 19 is provided in the other circumferential space between two adjacent through holes 13a and 13b and two adjacent through holes 13c and 13d. Furthermore, the two projections 19 are symmetrical with respect to the plane of symmetry P in terms of position and shape.

[0047] The shape, number, and position of the projections 19 are not limited to those in the example described above. For example, the first gasket 10 may have only one projection 19, or it may have three or more. Also, multiple projections 19 may be provided in the circumferential space between two adjacent through holes 13a, 13b and two adjacent through holes 13c, 13d. In this case, for example, the multiple projections 19 may be provided at equal or approximately equal angular intervals in the circumferential direction. Note that the multiple projections 19 do not have to be provided at equal angular intervals in the circumferential direction. Also, multiple projections 19 may be provided in the radial direction. In this case, the multiple projections 19 may or may not be aligned in the radial direction. Note that the radial direction is the direction along the seal side surface 11 that intersects the seal side surface 11, and the direction that intersects the inner circumferential end 11a and the outer circumferential end 11b of the seal side surface 11. The inner circumferential end 11a is the inner circumferential end of the seal side surface 11, and the outer circumferential end 11b is the outer circumferential end of the seal side surface 11. Furthermore, the projection 19 may be provided at any position on the seal side surface 11 where the projection 19, as described later, will exert its effect, such as between the bead 16b and the bead 17b, between the through hole 13a and the through hole 13b, or between the through hole 13c and the through hole 13d.

[0048] The first gasket 10 has the above-described structure and is integrally formed from an elastic material. The elastic material of the first gasket 10 is, for example, rubber. Specifically, the elastic material of the first gasket 10 can be, for example, ethylene propylene rubber (EPM), ethylene propylene diene rubber (EPDM), fluororubber (FKM), silicone rubber (VMQ), etc. The first gasket 10 is made from an elastic material and is flexible. In particular, when the first gasket 10 is large, each part of the first gasket 10 is flexible. The above description of the first gasket 10, especially the description of its shape, describes the first gasket 10 in an undeformed state, for example, in the state shown in the design drawings or other design-stage descriptions.

[0049] The second gasket 20 has the same configuration as the first gasket 10 and has the same or similar shape as the first gasket 10. For example, the second gasket 20 is the same as or substantially the same as the first gasket 10, and the only difference between the first gasket 10 and the second gasket 20 is whether they are used to seal the anode chamber S1 in the cell 100 or to seal the cathode chamber S2 by inversion, as shown in Figures 4 and 5.

[0050] As described above, the configuration of the second gasket 20 is the same as that of the first gasket 10, and the second gasket 20 has the same configuration as the first gasket 10, as shown in Figures 1 to 3. In Figures 1 to 3, the reference numerals for the components of the second gasket 20 are shown in parentheses, and the corresponding reference numerals for the components of the second gasket 20 are shown next to the reference numerals for the components of the first gasket 10.

[0051] As shown in Figures 1 to 3, the second gasket 20 has a sealing side 21 and a contact side 22 that correspond to the sealing side 11 and contact side 12 of the first gasket 10, respectively. The second gasket 20 also has through holes 23 (23a, 23b, 23c, 23d) that correspond to the through holes 13 (13a, 13b, 13c, 13d) of the first gasket 10, respectively. Furthermore, the second gasket 20 has a first sealing portion 24 and a second sealing portion 25 that correspond to the first sealing portion 14 and the second sealing portion 15 of the first gasket 10, respectively, and has a step portion 24a, an inner sealing portion 26, an inner sealing surface 26a, a bead 26b, an outer sealing portion 27, an outer sealing surface 27a, a bead 27b, a sealing surface 25a, and a bead 25b that correspond to the step portion 14a, an inner sealing portion 16, an inner sealing surface 16a, a bead 16b, an outer sealing portion 17, an outer sealing surface 17a, a bead 17b, a sealing surface 15a, and a bead 15b, respectively. In addition, the second gasket 20 has a contact surface 28 and a projection 29 that correspond to the contact surface 18 and projection 19 of the first gasket 10, respectively.

[0052] As described above, the second gasket 20 is the same as or substantially the same as the first gasket 10, and therefore the contact surface 28 of the second gasket 20 can contact the contact surface 18 of the first gasket 10 in a manner that coincides with or substantially coincides with each other. Also, the stepped portion 24a of the second gasket 20 can face the stepped portion 14a of the first gasket 10 in a manner that coincides with or substantially coincides with each other when viewed in the direction of contact. In other words, when the contact surface 28 of the second gasket 20 contacts the contact surface 18 of the first gasket 10, the inner sealing surface 26a of the second gasket 20 faces the inner sealing surface 16a of the first gasket 10, and coincides with or substantially coincides with each other when viewed in the direction of contact. As a result, the stepped portion 24a faces the stepped portion 14a in a manner that coincides with or substantially coincides with each other when viewed in the direction of contact, and the accommodating space 30 is formed. Furthermore, when the contact surface 28 of the second gasket 20 contacts the contact surface 18 of the first gasket 10, the beads 25b, 26b, and 27b of the second gasket 20 face away from the beads 15b, 16b, and 17b of the first gasket 10, respectively, and are aligned or nearly aligned when viewed in the direction of contact. Also, when the contact surface 28 of the second gasket 20 contacts the contact surface 18 of the first gasket 10, the projection 29 of the second gasket 20 faces away from the projection 19 of the first gasket 10, and are aligned or nearly aligned when viewed in the direction of contact.

[0053] The second gasket 20 has the above-described structure and is integrally formed from the same elastic material as the first gasket 10. The elastic material of the second gasket 20 is, for example, rubber. Specifically, the elastic material of the second gasket 20 may be, for example, ethylene propylene rubber (EPM), ethylene propylene diene rubber (EPDM), fluororubber (FKM), silicone rubber (VMQ), etc. The second gasket 20 is made from an elastic material and is flexible. In particular, when the second gasket 20 is large, each part of the second gasket 20 is flexible. Similar to the description of the first gasket 10, the above description of the second gasket 20, especially the description of its shape, describes the second gasket 20 in an undeformed state, for example, in the state shown in the design drawings or other design-stage descriptions.

[0054] Next, the operation of the first gasket 10 and the second gasket 20 having the above-described configuration, and the operation of the gasket device 2 will be explained. In order to assemble the cell 100, the first gasket 10 and the second gasket 20 are assembled with the electrolyte membrane 104 in between, as shown in Figure 4, to assemble the gasket device 2 and the membrane assembly 103. The assembled gasket device 2 and membrane assembly 103 are then sandwiched between a pair of separators 101 and 102 to assemble the cell 100. Note that the cell 100 in the assembled state shown in Figure 4 is in a free state, and no external force is applied to the cell 100.

[0055] As described above, the first gasket 10 and the second gasket 20 are the same or substantially the same. Therefore, in the assembled gasket device 2, each component of the first gasket 10 coincides with or substantially coincides with the component of the second gasket 20 that is symmetrically positioned with respect to the symmetry plane P in the first gasket 10, in the direction of the central axis x. As shown in Figure 4, in the assembled gasket device 2, in the direction of the central axis x, the first gasket 10 and the second gasket 20 face opposite each other, and the contact surface 18 of the first gasket 10 and the contact surface 28 of the second gasket 20 are in contact. Specifically, the entire or substantially entire contact surface 18 of the first gasket 10 and the entire or substantially entire contact surface 28 of the second gasket 20 are in contact. Furthermore, as shown in Figure 4, in the assembled gasket device 2, the stepped portion 14a of the first gasket 10 and the stepped portion 24a of the second gasket 20 face each other in the direction of the central axis x, forming a housing space 30. In the gasket device 2, in which the gasket device 2 and the membrane assembly 103 are assembled, the end portion 104a of the electrolyte membrane 104 of the membrane assembly 103 is housed in the housing space 30 of the gasket device 1. The inner sealing surface 16a of the first gasket 10 and the inner sealing surface 26a of the second gasket 20 are in contact with the electrolyte membrane 104 over their entire circumference. In addition, in the gasket device 2 in which the gasket device 2 and the membrane assembly 103 are assembled, gaps may be formed between the inner sealing surface 16a of the first gasket 10 and the electrolyte membrane 104, between the inner sealing surface 26a of the second gasket 20 and the electrolyte membrane 104, or between the inner sealing surface 16a and the electrolyte membrane 104 and between the inner sealing surface 26a and the electrolyte membrane 104.

[0056] As described above, in the first gasket 10, the positions of the through holes 13a and 13b are symmetrical or approximately symmetrical with respect to the plane of symmetry P, and in the second gasket 20, the positions of the through holes 23a and 23b are symmetrical or approximately symmetrical with respect to the plane of symmetry P. Therefore, as shown in Figures 4 and 6, in the assembled gasket device 1, the through hole 23b of the second gasket 20 faces the through hole 13a of the first gasket 10, and the through holes 13a and 23b communicate with each other. As a result, a through hole 3a is formed in the gasket device 2. Similarly, as shown in Figure 6, in the assembled gasket device 2, the through hole 23a of the second gasket 10 faces the through hole 13b of the first gasket 10, and the through holes 13b and 23a communicate with each other. As a result, a through hole 4b is formed in the gasket device 2. Similarly, in the first gasket 10, the through holes 13c and 13d are symmetrical or nearly symmetrical with respect to the plane of symmetry P, and in the second gasket 20, the through holes 23c and 23d are symmetrical or nearly symmetrical with respect to the plane of symmetry P. Therefore, as shown in Figure 6, in the assembled gasket device 2, the through hole 23d of the second gasket 20 faces the through hole 13c of the first gasket 10, and the through holes 13c and 23d communicate with each other. As a result, the through hole 4c is formed in the gasket device 2. Similarly, as shown in Figure 6, in the assembled gasket device 2, the through hole 23c of the second gasket 20 faces the through hole 13d of the first gasket 10, and the through holes 13d and 23c communicate with each other. As a result, the through hole 4d is formed in the gasket device 2.

[0057] As described above, the gasket device 2, which is assembled with the film bonding body 103, is sandwiched between separators 101 and 102, as shown in Figure 4, thereby assembling the cell 100. Specifically, separator 101 is positioned opposite the sealing side surface 11 of the first gasket 10 of the gasket device 2 and in contact with the first gasket 10, and separator 102 is positioned opposite the sealing side surface 21 of the second gasket 20 of the gasket device 1 and in contact with the second gasket 20.

[0058] In the assembled cell 100, separator 101 is in contact with beads 15b, 16b, and 17b, facing the first gasket 10. Separator 102 is in contact with beads 25b, 26b, and 27b, facing the second gasket 20. When a force is applied to separator 101 toward separator 102, and a force is applied to separator 102 toward separator 101, the assembled cell 100 becomes ready for use.

[0059] Figure 5 is a cross-sectional view showing cell 100 in use with a tightening load applied. In cell 100 in use, the beads 16b and 17b of the first gasket 10 are pressed against the separator 101, and the inner sealing surface 16a of the first gasket 10 is pressed against the electrolyte membrane 104, thereby sealing the anode chamber S1. Also in cell 100 in use, the beads 26b and 27b of the second gasket 20 are pressed against the separator 102, and the inner sealing surface 26a of the second gasket 20 is pressed against the electrolyte membrane 104, thereby sealing the cathode chamber S2. Contact between the inner sealing surfaces 16a and 26a in the containment space 30 and the electrolyte membrane 104 prevents communication between the anode chamber S1 and the cathode chamber S2, so-called cross-leakage. Furthermore, the contact surface 18 of the first gasket 10 and the contact surface 28 of the second gasket 20 are in contact, thereby preventing the sealed material in the anode chamber S1 from blowing out of the cell 100, and also preventing the sealed material in the cathode chamber S2 from blowing out of the cell 100. In the cell 100 in use, the contact surface 18 of the first gasket 10 and the contact surface 28 of the second gasket 20 are pressed against each other, and the space between the contact surfaces 18 and 28 is more firmly sealed.

[0060] Furthermore, in the cell 100 in use, the bead 15b of the first gasket 10 is pressed against the separator 101, and the bead 25b of the second gasket 20 is pressed against the separator 102. As a result, the through holes 3a to 3d between the separator 101 and the separator 102 are sealed to form a flow path 4.

[0061] Furthermore, in the first gasket 10, the inner circumference bead 16b is provided facing away from the inner sealing surface 16a, and similarly, in the second gasket 20, the inner circumference bead 26b is provided facing away from the inner sealing surface 26a. As a result, in the cell 100 in use, the bead 16b is pressed against the separator 101, further pressing the inner sealing surface 16a against the electrolyte membrane 104. Similarly, in the cell 100 in use, the bead 26b is pressed against the separator 102, further pressing the inner sealing surface 26a against the electrolyte membrane 104. Furthermore, in the first gasket 10, the outer circumference bead 17b is provided facing away from the contact surface 18, and similarly, in the second gasket 20, the outer circumference bead 27b is provided facing away from the contact surface 28. Therefore, in the cell 100 in use, the bead 17b is pressed against the separator 101, further pressing its contact surface 18 against the contact surface 28 of the second gasket 20. Similarly, in the cell 100 in use, the bead 27b is pressed against the separator 102, further pressing its contact surface 28 against the contact surface 18 of the first gasket 10. In this way, since the multiple beads 16b, 17b, 26b, and 27b are formed separately on the inner and outer circumference sides, the anode chamber S1 and cathode chamber S2 are more firmly sealed, further preventing the sealed material in the anode chamber S1 from blowing out of the cell 100, and further preventing the sealed material in the cathode chamber S2 from blowing out of the cell 100.

[0062] As described above, in use, the first gasket 10 and the second gasket 20 are sandwiched between the separator 101 and the separator 102 and subjected to a tightening load, thereby being compressed. For example, as shown in Figure 5, the separators 101 and 102 are pressed in opposing directions such that the tip 19a of the projection 19 of the first gasket 10 contacts the separator 101, and the tip 29a of the projection 29 of the second gasket 20 contacts the separator 102. However, in use, the separators 101 and 102 may be pressed in opposing directions such that the tip 19a of the projection 19 of the first gasket 10 does not contact the separator 101, and the tip 29a of the projection 29 of the second gasket 20 does not contact the separator 102.

[0063] As described above, the heights h2, h3, and h4 of the beads 15b, 16b, and 17b are each higher than the height h1 of the projection 19. For example, as shown in Figures 3 and 7, the heights h2, h3, and h4 of the beads 15b, 16b, and 17b are each higher than the height h1 of the projection 19 by half or approximately half of a predetermined compression allowance C. In this case, under the above-described usage conditions, when the gasket device 2 is compressed between the separators 101 and 102 by a predetermined compression allowance C or approximately a predetermined compression allowance C, the beads 15b, 16b, and 17b are compressed by half or approximately half of the predetermined compression allowance C, and the projection 19 comes into contact with the separator 101.

[0064] Similarly, the heights h2, h3, and h4 of the beads 25b, 26b, and 27b are each higher than the height h1 of the projection 29. For example, as shown in Figures 3 and 7, the heights h2, h3, and h4 of the beads 25b, 26b, and 27b are each higher than the height h1 of the projection 29 by half or approximately half of a predetermined compression allowance C. In this case, under the above-described usage conditions, when the gasket device 2 is compressed between the separators 101 and 102 by a predetermined compression allowance C or approximately a predetermined compression allowance C, the beads 25b, 26b, and 27b are compressed by half or approximately half of the predetermined compression allowance C, and the projection 29 comes into contact with the separator 102.

[0065] In this state, when cell 100 is further tightened and a further compressive tightening load is applied to the gasket device 2 between separators 101 and 102, the reaction force F of the gasket device 2 increases. This prevents or suppresses overcompression, where the beads 15b, 16b, 17b, 25b, 26b, and 27b are compressed more than necessary. Therefore, damage to the beads 15b, 16b, 17b, 25b, 26b, and 27b due to overcompression can be prevented or suppressed.

[0066] Specifically, as the clamping load on cell 100 is increased, and the assembled gasket device 2 is compressed as shown in the graph of Figure 8, the reaction force F of the gasket device 2 to this clamping load gradually increases until the projections 19 and 29 come into contact with the separators 101 and 102, respectively. During this time, the gap amount G decreases from gap amount G0 (see Figure 4) to gap amount G1 (see Figure 5). The gap amount G is the distance of the gap between separator 101 and separator 102 in the direction of reversal.

[0067] Then, if the tightening load on the cell 100 is further increased from this state, the reaction force from the protrusions 19 and 29 is added, and as shown in Figure 8, the reaction force F of the gasket device 2 increases. In other words, when the protrusions 19 and 29 come into contact with the separators 101 and 102 respectively, and the compression allowance C becomes a predetermined compression allowance, and the first gasket 10 and the second gasket 20 are further compressed beyond this predetermined compression allowance C, thereby further reducing the gap amount G, the rate at which the reaction force F of the gasket device 2 increases is greater than the rate at which the reaction force F increased before the compression allowance C became a predetermined compression allowance.

[0068] On the other hand, if the first gasket 10 does not have a projection 19 and the second gasket 20 does not have a projection 29, even if the gasket device 2 is compressed so that the crushing allowance C exceeds a predetermined crushing allowance and the gap amount G is further reduced, the rate of increase of the reaction force F of the gasket device 2 does not increase, or is lower than the rate of increase of the reaction force F of the gasket device 2 having projections 19 and 29.

[0069] In this manner, when a tightening load is applied to the first gasket 10 and the second gasket 20 that results in a compression amount of C or more, the projections 19 and 29 increase the reaction force F to this tightening load. Therefore, overcompression of the beads 15b, 16b, 17b, 25b, 26b, and 27b can be prevented or suppressed in use, and damage to the beads 15b, 16b, 17b, 25b, 26b, and 27b due to overcompression can be prevented or suppressed.

[0070] Figure 8 shows a graph illustrating the relationship between the reaction force F and the gap amount G. The solid line shows the relationship between the reaction force F and the gap amount G of the gasket device 2, while the dashed line shows the relationship between the reaction force F and the gap amount G of a gasket device composed of a conventional gasket without protrusions 19 and 29.

[0071] Furthermore, as shown in Figure 8, when a desired gap amount G range Gw is set, as described above, the rate of increase of the reaction force F of the gasket device 2 is higher than that of a conventional gasket device. Therefore, the load used to tighten the cell 100 equipped with the gasket device 2 in order to reduce the gap amount G is greater than the load used to tighten a cell equipped with a conventional gasket device. For this reason, the gasket device 2, which includes the first gasket 10 and the second gasket 20, makes it easy to set the gap amount G within the desired gap amount G range Gw.

[0072] Furthermore, by increasing the reaction force generated by the protrusions 19 and 29, the rate of increase in the reaction force F of the gasket device 2 can be increased. For this reason, in order to further increase the rate of increase in the reaction force F of the gasket device 2, the protrusions 19 and 29 may be shaped and configured to generate a larger reaction force. For example, by increasing the area that each of the protrusions 19 and 29 occupies on the sealing surface 11, the reaction force generated by the protrusions 19 and 29 can be increased.

[0073] Furthermore, as described above, since overcompression of beads 15b, 16b, 17b, 25b, 26b, and 27b in use is prevented or suppressed, the amount of compression of beads 15b, 16b, 17b, 25b, 26b, and 27b, and beads 23a and 25a can be set more accurately.

[0074] Furthermore, by setting the desired compression amount C such that the gap amount G when the gasket device 2 is compressed by the desired compression amount C falls within the range Gw of the desired gap amount G described above, it is possible to easily set the gap amount G within the range Gw of the desired gap amount G. For example, by making the gap amount G when the gasket device 2 is compressed by the desired compression amount C the maximum value of the gap amount G within the range Gw of the desired gap amount G, or a place near it, it is possible to easily set the gap amount G within the range Gw of the desired gap amount G.

[0075] As described above, the gasket 10 (first gasket 10 and second gasket 20) eliminates the need for strict control of the tightening load of the cell 100 during assembly of the water electrolysis apparatus 1, or it allows for a relaxation of the strictness of the tightening load of the cell 100. Furthermore, the first and second gaskets 10 and 20 can be easily brought into a state that exhibits suitable sealing performance. In addition, the gasket 10 (first gasket 10 and second gasket 20) eliminates the need for strict control of the gap amount G of the separators 101 and 102 when tightening the cell 100 during assembly of the water electrolysis apparatus 1, or it allows for a relaxation of the strictness of the control of the gap amount G of the separators 101 and 102 when tightening the cell 100.

[0076] On the other hand, if there are no protrusions 19 and 29, the bead may be crushed more than necessary if the clamping load on the cell 100 is excessive. This may damage the bead. Also, the separators 101 and 102 may come into contact with the diffusion layers 107 and 108, potentially damaging the film bonding body 103 and the diffusion layers 107 and 108. Thus, if there are no protrusions 19 and 29, strict control of the clamping load on the cell 100 is necessary. Furthermore, if there are no protrusions 19 and 29, strict control of the spacing between the separators 101 and 102 when clamping the cell 100 is necessary.

[0077] As described above, according to the gasket 10 of the embodiment of the present invention, it is possible to suppress overcompression in the cell 100.

[0078] Next, an example of a modified gasket device 2 according to an embodiment of the present invention will be described. Figure 9 is a schematic partial cross-sectional view of a water electrolysis apparatus 1 equipped with an example of a modified gasket device 2. As shown in Figure 9, the gaskets 10 may be used by stacking one gasket 10 on top of the other gasket 10 in the same orientation without reversing them. That is, as shown in Figure 9, the modified gasket device 2 is configured by stacking two gaskets 10 in the same orientation, and in the modified gasket device 2, the two gaskets 10 are overlapping, and the contact surface 12 of one gasket 10 is in contact with the sealing surface 11 of the other gasket 10. Also, the two gaskets 10 are stacked such that the same components of each are overlapping when viewed in the axial x direction. For example, the projection 19 of one gasket 10 is overlapping the projection 19 of the other gasket 10 when viewed in the axial x direction. Furthermore, in the modified gasket apparatus 2, the end portion 104a of the electrolyte membrane 104 is sandwiched between the inner sealing surface 16a of one gasket 10 and the bead 16b of the other gasket 10. Also, the projection of the projection 19 of one gasket 10 on the contact surface 18 in the axial x direction is in contact with the tip surface 19a of the projection 19 of the other gasket 10 (see Figure 5). The modified gasket apparatus 2 also provides the same functions and effects as the gasket 10 and gasket apparatus 2 described above.

[0079] 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.

[0080] 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.

[0081] For example, within the range in which the above-described effects are achieved, the second gasket 20 does not have to be exactly the same as the first gasket 10, but may be substantially the same, for example.

[0082] In the above explanation, gasket 10 (first gasket 10 and second gasket 20) was described as an example of an application to a water electrolysis apparatus. However, the application of gasket 10 is not limited to water electrolysis apparatuses. For example, gasket 10 can also be used in the cells of a fuel cell.

[0083] 1 Water electrolysis apparatus, 2 Gasket apparatus, 3 Flow path, 4a, 4b, 4c, 4d Through holes, 10 Gasket, 11 Seal side, 11a Inner circumferential end, 11b Outer circumferential end, 12 Contact side, 13, 13a, 13b, 13c, 13d Through holes, 14 First seal portion, 14a Step portion, 15 Second seal portion, 15a Seal surface, 15b Bead, 16 Inner seal portion, 16a Inner seal surface, 16b Bead, 17 Outer seal portion, 17a Outer seal surface, 17b Bead, 18 Contact surface, 19 Projection, 19a Tip, 30 Housing space, 100 Cell, 101, 102 Separator, 101a Surface, 101b Recess, 101c-101f Through holes, 103 Membrane assembly, 104 Electrolyte membrane, 104a end, 104b outer edge, 105 anode catalyst layer, 106 cathode catalyst layer, 107, 108 diffusion layer, C compression allowance, F reaction force, G gap amount, Gw range, h1, h2, h3, h4 height, P symmetrical plane, S1 anode chamber (space), S2 cathode chamber (space), x central axis

Claims

1. A gasket for sealing the space between each of a pair of opposing members and an intermediate member facing each of the pair of members in the opposing direction, wherein the gasket is formed in an annular shape from an elastic material, and one of the gaskets is superimposed on the other gasket in reverse to seal the space, comprising: a pair of annular surfaces facing each other, namely a sealing side and a contact side; a plurality of through holes penetrating between the sealing side and the contact side; a first sealing portion formed on the sealing side for sealing the space; and a plurality of second sealing portions formed on the sealing side on the outer circumference of the first sealing portion, surrounding each of the plurality of through holes, wherein the reaction force increases when the compression allowance between the pair of members exceeds a predetermined value.

2. The gasket according to claim 1, wherein when the compression allowance exceeds a predetermined value, the rate of increase of the reaction force with respect to the compression allowance increases.

3. The gasket according to claim 1 or 2, wherein, between the pair of members, the sealing surface faces one or the other of the pair of members, and the other portion of the sealing surface contacts one or the other of the pair of members when the compression amount exceeds a predetermined value.

4. The gasket according to claim 3, further comprising at least one projection formed on the side surface of the seal, wherein the projection contacts one or the other of the pair of opposing members when the compression amount exceeds a predetermined value.

5. The gasket according to claim 4, wherein the first sealing portion has at least one annular bead, the second sealing portion has at least one annular bead, and the height of the projection from the sealing side surface is lower than the height of the bead of the first sealing portion and the bead of the second sealing portion from the sealing side surface.

6. The gasket according to claim 5, wherein the projection extends along the first sealing portion.

7. The gasket according to claim 6, wherein the projection is located on the outer circumference side of the first sealing portion.

8. The gasket according to claim 4, wherein the projection is aligned with the plurality of through holes in the circumferential direction.

9. The gasket according to claim 4, comprising four through holes and two projections, two of the four through holes being adjacent to each other, the other two of the four through holes being adjacent to each other, one of the two projections being located in the circumferential space between one of the two adjacent through holes and the other of the two adjacent through holes, and the other projection being located in the circumferential space between one of the two adjacent through holes and the other of the two adjacent through holes.

10. The gasket according to claim 1, wherein the pair of members are separators for a water electrolyzer or a fuel cell cell, and the intermediate member is the electrolyte membrane of the cell.

11. A gasket for sealing the space between each of a pair of opposing members and an intermediate member facing each of the pair of members in the opposing direction, wherein the gasket is formed in an annular shape from an elastic material, and one of the gaskets is placed on top of the other gasket in the same orientation to seal the space, comprising: a pair of annular surfaces facing each other, which are a sealing side and a contact side; a plurality of through holes penetrating between the sealing side and the contact side; a first sealing portion formed on the sealing side for sealing the space; and a plurality of second sealing portions formed on the sealing side on the outer circumference of the first sealing portion, surrounding each of the plurality of through holes, wherein the reaction force increases when the compression allowance between the pair of members exceeds a predetermined value.

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