Sealed structure, stacked body, and water electrolysis device

Abstract

To prevent the deterioration of sealability shown when a force directed from the inside to the outside of a frame is applied to a seal member.SOLUTION: The sealed structure comprises: a sheet-shaped membrane layer disposed along a plane orthogonally intersecting the stacking direction; a plate-shaped member which is adjacently disposed to oppose the membrane layer, and includes an attachment part that has an edge disposed on the edge side of the plate-shaped member and having an edge face opposing the membrane layer, an attachment face concave relative to the edge face, and a tilting face tilting toward the edge face from the attachment face, and has a gap between the tilting face and the membrane layer; and a seal member which is disposed on the opposite side of the edge relative to the tilting face, has a shape of a frame disposed adjacently to the tilting face when viewed from the membrane layer, seals the gap between the membrane layer and the plate-shaped member, and is deformable toward the gap when a force is applied from the inside to the outside of the frame.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a sealed structure, a laminate, and a water electrolysis device. [Background technology]

[0002] As an example of a water electrolysis device, as described in Patent Document 1, there is known a water electrolysis device having a structure in which a plurality of reversible cells are stacked, each of which has a solid polymer electrolyte membrane, separators arranged on both sides of the solid polymer electrolyte membrane, and sealing members provided in grooves in the separators. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-197079 A Summary of the Invention [Problem to be solved by the invention]

[0004] A water electrolysis device used in a hydrogen generation plant may be operated with the pressure in the internal space increased to approximately 3 to 10 MPa in order to reduce the labor required for supplying hydrogen gas to a hydrogen storage tank in the hydrogen generation plant.

[0005] An object of the present disclosure is to suppress deterioration of sealing properties when a force is applied to a seal member from inside a frame toward outside the frame. [Means for solving the problem]

[0006] A first aspect of the present disclosure is a sealing structure for use in a stack having a plurality of unit cells stacked in a stacking direction. The sealing structure includes: A sheet-like membrane layer along a plane perpendicular to the lamination direction; A plate-like member adjacent to and facing the membrane layer, an edge portion provided on an edge side of the plate-like member and having an edge surface facing the film layer; a mounting portion having a mounting surface that is concave with respect to the edge surface and an inclined surface that is inclined from the mounting surface toward the edge surface, the mounting portion having a gap between the inclined surface and the membrane layer; A plate-like member having a sealing member that is arranged on the opposite side of the inclined surface from the edge portion, has a frame shape adjacent to the inclined surface when viewed from the film layer side, and seals between the film layer and the plate-like member, the sealing member being deformable toward the gap when a force is applied from inside the frame toward the outside of the frame; has. Effect of the Invention

[0007] According to the present disclosure, it is possible to suppress deterioration of sealing performance when a force is applied to the sealing member from inside the frame toward outside the frame. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of a hydrogen generation plant having a water electrolysis apparatus according to an embodiment; [Diagram 2] 1 is a side cross-sectional view of a water electrolysis device according to an embodiment. [Diagram 3] FIG. 1 is a plan view of a water electrolysis device according to an embodiment. [Figure 4] 1 is an enlarged cross-sectional view of a water electrolysis device according to an embodiment; [Diagram 5] FIG. 2 is an exploded cross-sectional view of a unit cell and its surroundings according to the embodiment. [Figure 6] 1A is an enlarged cross-sectional view of the sealing structure of the embodiment in an assembled state, FIG. 1B is an enlarged cross-sectional view of the sealing structure of the embodiment in a pre-pressurized state, and FIG. 1C is an enlarged cross-sectional view of the sealing structure of the embodiment in an internal pressure applied state. [Figure 7] 6 is a graph showing the distribution of contact surface pressure between a gasket and a groove of an embodiment in a preloaded state and in an internally pressurized state. [Figure 8] 11 is a graph showing the distribution of contact surface pressure between a gasket and a membrane layer of an embodiment in a pre-loaded state and in an internal pressure applied state. [Figure 9]1A is an enlarged cross-sectional view of a sealing structure of a comparative embodiment in an assembled state, FIG. 1B is an enlarged cross-sectional view of a sealing structure of a comparative embodiment in a preloaded state, and FIG. 1C is an enlarged cross-sectional view of a sealing structure of a comparative embodiment in an internal pressure applied state. [Figure 10] 13 is an enlarged cross-sectional view of a modified example of the gasket of the sealing structure according to the embodiment. FIG. [Figure 11] 1A is an enlarged cross-sectional view of a sealing structure having a modified gasket of an embodiment in a pre-pressurized state, and FIG. 1B is an enlarged cross-sectional view of a sealing structure having a modified gasket of an embodiment in an internal pressure applied state. [Figure 12] 11 is a graph showing the distribution of contact surface pressure between a groove portion and a modified example of the gasket of the embodiment in a preloaded state and in an internally pressurized state. [Figure 13] 11 is a graph showing the distribution of contact surface pressure between a modified example of the gasket of the embodiment and a membrane layer in a pre-loaded state and in an internal pressure applied state. [Figure 14] 13 is a side cross-sectional view of a modified example of a plate-shaped member of the sealing structure according to the embodiment. FIG. [Figure 15] FIG. 11 is an enlarged cross-sectional view of a modified example of the sealing structure according to the embodiment. [Figure 16] 13 is a side cross-sectional view of a modified example of the film member of the sealing structure according to the embodiment. FIG. [Figure 17] 13 is a side cross-sectional view of a modified example of the film member of the sealing structure according to the embodiment. FIG. [Figure 18] FIG. 11 is a side cross-sectional view of a modified example of the water electrolysis device according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The drawings are not necessarily drawn to scale, and some features may be exaggerated or omitted.

[0010] Fig. 1 is a schematic diagram of an example of a hydrogen generation plant having a water electrolysis apparatus according to the present disclosure. As shown in Fig. 1, the hydrogen generation plant according to the present disclosure has a rectifier E1, a water electrolysis apparatus E2, a pure water production apparatus E3, a pure water storage tank E4, an oxygen gas-liquid separator E5, a hydrogen gas-liquid separator E6, a dehumidifier E7, and a hydrogen storage tank E8.

[0011] The rectifier E1 converts the AC current into a DC current and supplies the DC current to the water electrolysis device E2. The pure water production device E3 removes impurities from tap water to produce pure water (H2O), and supplies the pure water to the pure water storage tank E4. The pure water storage tank E4 stores the pure water supplied from the pure water production apparatus E3. The pure water stored in the pure water storage tank E4 is supplied to the water electrolysis apparatus E2 via the oxygen gas-liquid separator E5. The water electrolysis device E2 can generate hydrogen gas (H2) and oxygen gas (O2) by electrolyzing the supplied pure water. The oxygen gas generated by the water electrolysis device E2 is supplied to an oxygen gas-liquid separator E5 together with the pure water. The hydrogen gas generated by the water electrolysis device E2 is supplied to a hydrogen gas-liquid separator E6 together with the pure water. The water electrolysis device E2 will be described in detail later.

[0012] The oxygen gas-liquid separator E5 separates the oxygen gas and the pure water supplied from the water electrolysis apparatus E2 and releases the oxygen gas. The pure water separated from the oxygen gas by the oxygen gas-liquid separator E5 is supplied again to the water electrolysis apparatus E2. The hydrogen gas-liquid separator E6 separates the hydrogen gas and the pure water supplied from the water electrolysis apparatus E2. The pure water separated from the hydrogen gas in the hydrogen gas-liquid separator E6 is supplied again to the water electrolysis apparatus E2 via the oxygen gas-liquid separator E5. The hydrogen gas separated from the pure water in the hydrogen gas-liquid separator E6 is supplied to the dehumidifier E7. The dehumidifier E7 removes moisture from the supplied hydrogen gas, and supplies the hydrogen gas from which moisture has been removed to the hydrogen reservoir E8. The hydrogen reservoir E8 stores the hydrogen gas from which moisture has been removed by the dehumidifier E7. Supply means (not shown) is provided between the hydrogen reservoir E8 and the dehumidifier E7, or the hydrogen gas-liquid separator E6, or the water electrolysis device E2. The supply means includes a pressure boosting mechanism, such as a pressure pump. The supply means pressurizes the hydrogen gas generated in the water electrolysis device E2, thereby increasing the supply efficiency of the hydrogen gas toward the hydrogen reservoir E8.

[0013] <Water electrolysis device E2> The water electrolysis apparatus E2 is a bipolar cell type water electrolysis apparatus and includes a laminate 10, an end wall 22, an end wall 24, a separator 26, and a gasket 50, as shown in FIG.

[0014] <Laminate 10> The laminate 10 has a plurality of unit cells UC. The laminate 10 is formed by stacking a plurality of unit cells UC in a stacking direction. The laminate 10 further has a sealing structure 30. The unit cells UC and the sealing structure 30 will be described in detail later.

[0015] <End Wall 22> The end wall 22 is a flat plate-like member provided at an end of the laminate 10 in a first direction along the stacking direction, as shown in Fig. 2. That is, the end wall 22 is adjacent to a unit cell UC located at an end of the laminate 10 in the first direction. The end wall 22 extends along a plane perpendicular to the stacking direction. The end wall 22 is rectangular when viewed from the stacking direction, as shown in Fig. 3.

[0016] 2, the end wall 22 has a port portion 22a and a port portion 22b. The port portions 22a and 22b each have a hole penetrating the end wall 22 in the plate thickness direction. The portions of the port portions 22a and 22b opposite to the stack 10 are each connectable to the oxygen-gas-liquid separator E5. The port portion 22a allows the pure water supplied from the oxygen-gas-liquid separator E5 to flow into the inside of the water electrolysis apparatus E2. That is, the port portion 22a distributes the pure water between the stack 10. The port portion 22b allows the oxygen gas supplied toward the oxygen-gas-liquid separator E5 to flow out together with the pure water. That is, the port portion 22b distributes oxygen between the stack 10. The end wall 22 is used as an anode in the water electrolysis device E2.

[0017] <End Wall 24> As shown in Fig. 2, the end wall 24 is a flat member provided at an end of the laminate 10 in the second direction, which is the opposite direction to the first direction. That is, the end wall 24 is adjacent to the unit cell UC located at the end of the laminate 10 in the second direction. The end wall 24 extends along a plane perpendicular to the stacking direction. As shown in Fig. 3, the end wall 24 has a rectangular shape that overlaps with the end wall 22 when viewed from the stacking direction.

[0018] 2, the end wall 24 has a port portion 24a. The port portion 24a has a hole penetrating the end wall 24 in the plate thickness direction. A portion of the port portion 24a opposite the stack 10 is connectable to the hydrogen gas-liquid separator E6. The port portion 24a causes hydrogen gas supplied toward the hydrogen gas-liquid separator E6 to flow out of the water electrolysis apparatus E2 together with pure water. In other words, the port portion 24a causes hydrogen to flow between the stack 10. The end wall 24 is used as a cathode in the water electrolysis device E2.

[0019] <Separator 26> As shown in Fig. 2, the separator 26 is a flat plate-like member provided between two unit cells UC adjacent to each other in the stacking direction. A plurality of separators 26 are provided corresponding to the plurality of unit cells UC constituting the stack 10. The separator 26 extends along a plane perpendicular to the stacking direction. As shown in Fig. 3, the separator 26 has a rectangular shape that overlaps with the end walls 22, 24 when viewed from the stacking direction.

[0020] 2, the separator 26 has a through-hole 26p. The through-hole 26p penetrates the separator 26 in the plate thickness direction. The through-hole 26p connects two unit cells UC adjacent to each other in the stacking direction. The surface of the separator 26 facing the end wall 22 is used as an anode, and the surface of the separator 26 facing the end wall 24 is used as a cathode.

[0021] Two separators 26 arranged adjacent to each other so as to sandwich one unit cell UC function as partition walls that divide the unit cell UC. The end wall 22 and the separator 26a adjacent to the end wall 22 function as partition walls that divide the unit cell UC. The end wall 24 and the separator 26b adjacent to the end wall 24 function as partition walls that divide the unit cell UC. In other words, the end wall 22 and the separator 26a, the end wall 24 and the separator 26b, and a pair of separators 26 adjacent in the stacking direction each form a space 28 capable of accommodating a unit cell UC. The end wall 22, the end wall 24, and the separator 26 are preferably made of stainless steel, titanium, or a titanium alloy. The end wall 22, the end wall 24, and the separator 26 each face a membrane layer LM (described in detail later) of the unit cell UC. The end wall 22, the end wall 24, and the separator 26 are each an example of a plate-like member.

[0022] <Gasket 50> As shown in FIG. 2, a plurality of gaskets 50 are provided corresponding to a plurality of unit cells UC constituting the laminate 10. Specifically, the gaskets 50 are provided for each unit cell UC on both sides of the membrane layer LM of the unit cell UC in the stacking direction. That is, two gaskets 50 are provided for each space 28. The gaskets 50 are formed so as to overlap with grooves 42, which will be described later, when viewed from the stacking direction. The gaskets 50 are formed in a rectangular frame shape surrounding an anode current collector AD or a cathode current collector CD, which will be described later, when viewed from the stacking direction. A pair of gaskets 50 provided in one space 28 has the function of sealing the space 28. The gaskets 50 are an example of a sealing member. The gaskets 50 will be described in more detail below.

[0023] <Unit cell UC> 4 and 5, the unit cell UC has a membrane layer LM and a pair of current collectors PC. The unit cell UC is configured to be capable of generating hydrogen gas and oxygen gas by electrolyzing supplied pure water.

[0024] The membrane layer LM extends along a plane perpendicular to the stacking direction, and has a rectangular shape when viewed from the stacking direction overlapping with the end walls 22, 24 and the separator 26. The membrane layer LM has a solid polymer membrane PM, a catalyst membrane CT, and a film member FM.

[0025] The solid polymer membrane PM is a sheet-like membrane that extends along a plane perpendicular to the lamination direction. The solid polymer membrane PM is preferably an electrolyte membrane. The solid polymer membrane PM is a membrane that converts hydrogen generated by the electrolysis reaction of pure water into hydrogen. + is passable.

[0026] The catalyst membrane CT is a membrane-like member provided on each of both sides of the solid polymer membrane PM. The catalyst membrane CT promotes the electrolysis reaction of pure water in the unit cell UC. The catalyst membrane CT is preferably fixed to the solid polymer membrane PM.

[0027] The film members FM are frame-shaped members provided on both sides of the solid polymer membrane PM so as to surround the catalyst membrane CT when viewed from the stacking direction. The film members FM are made of resin. The film members FM are preferably made of, for example, polyethylene naphthalate. The film members FM have higher rigidity than the solid polymer membrane PM. The film members FM are preferably fixed to the solid polymer membrane PM. The membrane layer LM having the solid polymer membrane PM to which the film members FM are fixed has higher rigidity and is easier to handle than a membrane layer LM having a solid polymer membrane PM to which the film members FM are not fixed, as compared with a membrane layer LM having a solid polymer membrane PM to which the film members FM are not fixed, and thus has excellent handleability. The film members FM may be fixed to surround the edge of the solid polymer membrane PM when viewed from the stacking direction (see FIGS. 16 and 17). The film members FM are preferably capable of sealing against the fluid contained inside the water electrolysis device E2.

[0028] The pair of current collectors PC are members provided as a pair on both sides of the membrane layer LM. The pair of current collectors PC includes an anode current collector AD and a cathode current collector CD. The anode current collector AD is disposed on the end wall 22 side of the membrane layer LM as a cathode. The cathode current collector CD is disposed on the end wall 24 side of the membrane layer LM as an anode. The anode current collector AD and the cathode current collector CD are each rectangular and smaller than the membrane layer LM when viewed from the stacking direction. The anode current collector AD and the cathode current collector CD are disposed so as to overlap each other when viewed from the stacking direction. The anode current collector AD and the cathode current collector CD are formed from a porous material. The anode current collector AD and the cathode current collector CD can be impregnated with pure water. The anode current collector AD and the cathode current collector CD are each formed so as to be partitioned by a sealing structure 30 described later. The anode current collector AD and the cathode current collector CD have the same thickness in the stacking direction.

[0029] In the water electrolysis device E2, H generated by electrolysis of pure water + moves to the cathode side through the solid polymer membrane layer 13. At this time, H generated by electrolysis of pure water + is converted into hydrogen gas (H2) through a reduction reaction (see Figure 2).

[0030] <Sealed structure 30> 2, a plurality of sealing structures 30 are provided corresponding to a plurality of unit cells UC forming the laminate 10. As shown in FIG. 4, the sealing structure 30 includes the above-mentioned membrane layer LM, a plate-shaped member 40, and a gasket 50.

[0031] The plate-like member 40 is a flat member having a rectangular shape when viewed from the stacking direction. The plate-like member 40 corresponds to any one of the end walls 22, 24, or the separator 26. As shown in FIG. 5, the plate-like member 40 has an edge portion 41 and a groove portion 42. The edge portion 41 is a portion on the edge side of the plate-shaped member 40. The plate surface of the edge portion 41 that faces the membrane layer LM is the edge surface 41a. The edge portion 41 is a portion of the plate-shaped member 40 that is closer to the edge than the groove portion 42 described below. In the edge portion 41, the surface that is perpendicular to the edge surface 41a and faces the edge side with respect to the center side of the plate-shaped member 40 is the outer peripheral surface 41b. The outer peripheral surface 41b is aligned along the stacking direction.

[0032] As shown in Fig. 5, the groove portion 42 is a groove that is recessed into the edge surface 41a on the center side of the plate-shaped member 40 relative to the edge portion 41. The groove portion 42 is formed in a rectangular frame shape along the edge portion 41 on the inside of the plate-shaped member 40 when viewed from the stacking direction. The groove portion 42 is capable of mounting a gasket 50, as shown in Fig. 4. The groove portion 42 is an example of a mounting portion. That is, the mounting portion of the sealing structure 30 is formed in a groove shape in a cross-sectional view along the stacking direction. The groove portion 42 has a groove bottom 42a and an inclined surface 42b.

[0033] The groove bottom 42a has a surface parallel to the plate surface of the plate-shaped member 40. That is, the groove bottom 42a is parallel to the edge surface 41a. The groove bottom 42a is formed so as to come into contact with a contact surface 51 (described later) of the gasket 50. The groove bottom 42a is an example of a mounting surface.

[0034] The inclined surface 42b is a surface that slopes linearly from the groove bottom 42a toward the edge surface 41a in a cross-sectional view along the stacking direction. The inclined surface 42b intersects so as to be inclined with respect to the stacking direction. The inclined surface 42b connects the groove bottom 42a and the edge surface 41a. The inclined surface 42b is inclined by an inclination angle A1 with respect to the groove bottom 42a. The inclination angle A1 satisfies 0 degrees < A1 < 90 degrees. The inclined surface 42b is formed in a rectangular frame shape when viewed from the stacking direction.

[0035] <Details of the gasket 50> The gasket 50 is a frame-shaped member arranged along the groove portion 42 when viewed from the stacking direction. The gasket 50 is arranged closer to the center of the plate-like member 40 than the inclined surface 42b when viewed from the stacking direction. In other words, as shown in FIG. 4, the gasket 50 is arranged on the side opposite to the edge portion 41 with respect to the inclined surface 42b in a cross-sectional view along the stacking direction. The gasket 50 is arranged so as to be adjacent to the inclined surface 42b when viewed from the film layer LM side.

[0036] The gasket 50 has a wedge-shaped cross section as shown in FIGS. 4 and 5. Specifically, the gasket 50 has an end face portion 51, an end face portion 52, an outer peripheral portion 53, an inner peripheral portion 54, an inclined portion 55, and a corner portion 56 in a cross-sectional view along the stacking direction.

[0037] The end face portion 51 is a portion that faces parallel to the groove bottom 42a when the gasket 50 is not attached to the groove portion 42, as shown in FIGS. 4 and 5. The end face portion 51 has an end face 51a. The end face 51a is a surface facing the groove bottom 42a side in the stacking direction. The end face 51a comes into contact with the groove bottom 42a when the gasket 50 is attached to the groove portion 42.

[0038] As shown in FIGS. 4 and 5, the end face portion 52 is a portion that faces parallel to the film layer LM when not assembled. The end face portion 52 has an end face 52a. The end face 52a is a face facing the film layer LM side in the stacking direction. In the embodiment, the end face 52a contacts the film member FM during assembly. In other words, a film member FM is provided between the solid polymer membrane PM of the film layer LM and the end face portion 52 of the gasket 50.

[0039] As shown in FIGS. 4 and 5, the outer peripheral portion 53 is a portion on the outer peripheral side of the gasket 50. The outer peripheral portion 53 has an outer peripheral surface 53a. The outer peripheral surface 53a is a surface parallel to the outer peripheral surface 41b of the plate-like member 40. The outer peripheral surface 53a faces the edge side with respect to the center side of the plate-like member 40. The outer peripheral surface 53a is along the stacking direction. The outer peripheral portion 53 is connected to the end face portion 51.

[0040] As shown in FIGS. 4 and 5, the inner peripheral portion 54 is a portion on the inner peripheral side of the gasket 50. The inner peripheral portion 54 has an inner peripheral surface 54a. The inner peripheral surface 54a is a surface parallel to the outer peripheral surface 53a. The inner peripheral surface 54a faces the center side with respect to the edge side of the plate-like member 40. The inner peripheral surface 54a is along the stacking direction. The inner peripheral portion 54 is connected to the end face portion 51 and the end face portion 52.

[0041] As shown in FIGS. 4 and 5, the inclined portion 55 is a portion connecting the outer peripheral portion 53 and the end face portion 52. The inclined portion 55 has an inclined surface 55a. The inclined surface 55a is a surface that linearly inclines from the end face portion 52 toward the outer peripheral portion 53 in a cross-sectional view along the stacking direction. The inclined surface 55a is inclined by an inclination angle A2 with respect to the end face portion 52. That is, the inclined portion 55 is inclined by the inclination angle A2 with respect to the groove bottom 42a. The inclination angle A2 satisfies 0 degrees < A2 < 90 degrees. The inclination angle A2 is preferably smaller than the inclination angle A1 formed by the inclined surface 42b of the groove portion 42. The length (thickness) of the gasket 50 having the inclined portion 55 in the stacking direction becomes smaller as it progresses from the inner peripheral portion 54 side to the outer peripheral portion 53 side in a cross-sectional view along the stacking direction.

[0042] As shown in Fig. 4, the corner portion 56 is a portion that connects the inclined portion 55 and the outer circumferential portion 53. When the gasket 50 is attached to the groove portion 42, the corner portion 56 preferably comes into contact with the inclined surface 42b of the groove portion 42, as shown in Fig. 5. When the gasket 50 is attached to the groove portion 42, the inclined portion 55 of the gasket 50 faces the inclined surface 42b of the groove portion 42. At this time, a part of the inclined portion 55 may come into contact with the inclined surface 42b.

[0043] The gasket 50 is preferably made of an elastomer, such as silicone rubber, EPDM (ethylene propylene diene monomer) rubber, or fluororubber. The gasket 50 made of an elastomer has a thickness in the stacking direction greater than each of the anode current collector AD and the cathode current collector CD.

[0044] As shown in Fig. 4, the gasket 50 is disposed so as to be sandwiched between the plate-shaped member 40 and the membrane layer LM. At this time, a gap G0 is formed between the plate-shaped member 40 and the membrane layer LM. The gap G0 has a gap G1 and a gap G2. The gap G1 is a gap between the edge surface 41a of the plate-shaped member 40 and the membrane layer LM. The gap G2 is a gap between the inclined surface 42b of the plate-shaped member 40 and the membrane layer LM. In other words, a space forming the gap G0 is formed between the plate-shaped member 40 and the membrane layer LM. The space that forms the gap G0 on the edge portion 41 side of the gasket 50 is connected to the external space of the water electrolysis apparatus E2. The height of the gap G2 in the stacking direction decreases from the center side of the plate-shaped component 40 toward the edge portion 41 side in a cross-sectional view along the stacking direction.

[0045] 4, the gaskets 50 are provided on both sides of the membrane layer LM in the stacking direction. That is, a pair of gaskets 50 provided in one space 28 are in contact with the membrane layer LM at their end surface portions 52 so as to sandwich the membrane layer LM therebetween.

[0046] The water electrolysis apparatus E2 is in an assembled state by further attaching end walls 22, 24 to both ends in the stacking direction of the stack 10 to which the separators 26 and the gaskets 50 are attached (see FIGS. 2 and 6(a)). The assembled water electrolysis device E2 is compressed in the stacking direction by a compression means (not shown) having a clamp device or a combination of metal fittings such as bolts and nuts, for the purpose of fixing the relative positions of the components of the water electrolysis device E2. At this time, the water electrolysis device E2 and the components of the water electrolysis device E2 are pre-compressed by being compressed in the stacking direction. In the pre-compressed water electrolysis device E2, the gasket 50 is compressed and deformed so that the thickness in the stacking direction is equal to that of the anode current collector AD and the cathode current collector CD (see FIG. 6(b)). The length of the gaps G1, G2 in the stacking direction in the pre-compressed state is smaller than the length of the gaps G1, G2 in the assembled state in the stacking direction, as shown in FIGS. 6(a) and 6(b). The gasket 50 in the pre-compressed state is compressed and deformed, and thus generates a repulsive force due to the elastomer. Therefore, the surface pressure between the end face portion 51 of the gasket 50 and the membrane layer LM and the surface pressure between the end face portion 52 and the groove portion 42 in the pre-pressurized state are higher than the surface pressure in the assembled state, so that the gasket 50 in the pre-pressurized state has higher sealing performance than in the assembled state. The gasket 50 in the preloaded state is in surface contact with the groove 42 from a position P1 on the innermost periphery 54 side to a position P2 on the outermost periphery 53 side (see FIG. 6(b)). The gasket 50 in the pre-loaded state is in surface contact with the membrane layer LM from a position Q1 on the innermost periphery side to a position Q2 on the outermost periphery side (see FIG. 6(b)).

[0047] In order to reduce the labor required for the supply of hydrogen gas to the hydrogen reservoir E8, the water electrolysis apparatus E2 may be used in a state where the pressure in the internal space of the water electrolysis apparatus E2 is increased to 3 to 10 MPa so as to increase the pressure within the frame of the gasket 50. Specifically, when the pressure in the internal space of the water electrolysis apparatus E2 is increased, the output of the boost mechanism of the supply means that supplies hydrogen gas generated in the water electrolysis apparatus E2 toward the hydrogen reservoir E8 can be reduced by the amount of the increased pressure. At this time, the gasket 50 is in an internal pressure applied state in which a force (pressure) is applied from the inside of the frame to the outside of the frame, as shown in FIG. 6(c). At this time, the gasket 50 deforms toward the gap G2. Specifically, the gasket 50 deforms so as to reduce the space that forms the gap G2. In other words, the gasket 50 deforms so as to escape into the gap G2 as a whole. At this time, it is preferable that the deformation of the gasket 50 is accompanied by elastic deformation. At this time, the deformation of the gasket 50 may be accompanied by volumetric compression of the elastomer.

[0048] When the water electrolysis apparatus E2 changes from a pre-pressurized state to an internal pressure applied state, the gasket 50 deforms so as to expand the contact surface with the groove 42 to a position P3 which is closer to the edge 41 than the position P2. At this time, the gasket 50 deforms so as to expand the contact surface with the membrane layer LM to a position Q3 which is closer to the edge 41 than the position Q2. The position of the contact surface between the gasket 50 and the groove 42 closest to the inner periphery 54 in the internal pressure applied state is the same position P1 as in the pre-loaded state. The position of the contact surface between the gasket 50 and the membrane layer LM closest to the inner periphery 54 in the internal pressure applied state is the same position Q1 as in the pre-loaded state. Note that the positions of the contact surfaces between the gasket 50 and the groove 42 or the membrane layer LM closest to the inner periphery 54 in the internal pressure applied state may be positions closer to the edge 41 than the respective positions in the pre-loaded state. When the water electrolysis apparatus E2 changes from a pre-pressurized state to an internal pressure applied state, the contact pressure between the gasket 50 and the groove 42 from position P1 to position P3 increases from the contact pressure in the pre-pressurized state, as shown in the graph of Fig. 7. At this time, the contact pressure between the gasket 50 and the membrane layer LM from position Q1 to position Q3 increases from the contact pressure in the pre-pressurized state, as shown in the graph of Fig. 8. The graph of the contact pressure between the gasket 50 and the groove 42 shown in Fig. 7 and the graph of the contact pressure between the gasket 50 and the membrane layer LM shown in Fig. 8 were each obtained by a simulation analysis using the finite element method. The increase in these contact pressures will be described in detail later.

[0049] Next, the operation and effects of the present disclosure will be described. In this description, a sealing structure 30H as a comparative embodiment to the embodiment will be described with reference to Fig. 9. In the description of the sealing structure 30H, when parts and the like similar to those of the sealing structure 30 of the embodiment are used, the reference numerals and names of the parts and the like will be used as they are.

[0050] As shown in FIG. 9, a sealing structure 30H of the comparative embodiment has a plate-shaped member 40H and a gasket 50H instead of the plate-shaped member 40 and the gasket 50 of the embodiment. 9, the gasket 50H has a solid circular cross section. That is, the gasket 50H does not have an end surface portion 51, an end surface portion 52, an outer circumferential portion 53, an inner circumferential portion 54, or an inclined portion 55. The gasket 50H is made of an elastomer. Since the gasket 50H has a solid circular cross section, it comes into point contact or line contact with the membrane layer LM in an assembled state.

[0051] As shown in FIG. 9, the plate-shaped member 40H has a groove 42H instead of the groove 42. The groove 42H is a rectangular groove that is recessed with respect to the edge surface 41a in a cross-sectional view along the stacking direction. The wall surface of the groove 42H facing the edge 41 is perpendicular to the edge surface 41a. That is, the groove 42H of the comparative embodiment does not have an inclined surface 42b. Moreover, the gap GH formed between the plate-like member 40H on which the gasket 50H is disposed and the membrane layer LM does not have a gap G2 formed between the inclined surface 42b and the membrane layer LM. Other than the above, the comparative sealing structure 30H has the same configuration as the sealing structure 30.

[0052] In the comparative sealing structure 30H, when the water electrolysis apparatus E2 is in a pre-pressurized state, the gasket 50H attached to the groove 42H is compressed and deformed in the stacking direction while being sandwiched between the membrane layer LM and the groove 42H, as shown in Fig. 9(b) . The gasket 50H is compressed and deformed with the transition from the assembled state to the pre-pressurized state, and thereby the contact state with the membrane layer LM transitions from point contact or line contact to surface contact.

[0053] Thereafter, when the pressure in the internal space of the water electrolysis apparatus E2 is increased, a force from inside the frame toward the outside of the frame is applied to the gasket 50H, and the gasket 50H is compressed and deformed toward the wall surface standing on the edge 41 side of the groove 42H, as shown in Fig. 9(c). At this time, there is a risk that the gasket 50H will deform so that a part of the membrane layer LM side will be wedged into the gap GH. If a part of the gasket 50H is deformed so as to be wedged into the gap GH, there is a risk that the gasket 50H will be damaged and the sealing property of the gasket 50H will be deteriorated.

[0054] In addition, at this time, there is a risk that the elastomer forming the gasket 50H may be deteriorated due to the pressure in the internal space of the water electrolysis apparatus E2. The deterioration of the elastomer reduces the repulsive force caused by the elastomer, and reduces the surface pressure between the gasket 50H and the groove 42H and the membrane layer LM. The reduction in the surface pressure between the gasket 50H and the groove 42H and the membrane layer LM deteriorates the sealing performance of the sealing structure 30H. Furthermore, in a pair of gaskets 50H provided in the space 28 that defines the unit cell UC, if the gaskets 50H are different in degree of deterioration, the gasket 50H with less deterioration may be pushed into the gasket 50H with more deterioration. In this case as well, the surface pressure between the gasket 50H with less deterioration and the groove 42H and the membrane layer LM decreases, thereby deteriorating the sealing performance of the sealing structure 30H.

[0055] Furthermore, the direction of pressure applied to the gasket 50H in the internal space of the water electrolysis apparatus E2 is perpendicular to the direction of the surface pressure between the gasket 50H and the membrane layer LM and the groove 42H. In this case, the gasket 50H is unlikely to increase the surface pressure on the membrane layer LM and the groove 42H when pressure is applied. Therefore, when the pressure in the internal space of the water electrolysis apparatus E2 is increased, the gasket 50H may not be able to increase the surface pressure between the membrane layer LM and the groove 42H to a threshold value at which the gasket 50H can exhibit sealing properties against pressure. Furthermore, when the pressure becomes greater than the frictional force caused by the surface pressure between the gasket 50H and the membrane layer LM, the gasket 50H may be deformed and damaged by the pressure so as to blow through to the edge 41 side. As described above, there is a risk that the sealing performance of the sealing structure 30H will deteriorate as the pressure in the internal space of the water electrolysis apparatus E2 increases.

[0056] In contrast, the sealing structure 30 of the embodiment has an inclined surface 42b of the groove 42. In the sealing structure 30, when the pressure in the internal space of the water electrolysis device E2 is increased, the gasket 50 is subjected to a force from inside the frame to outside the frame, as shown in Fig. 6(c), and deforms toward the gap G2. At this time, the gasket 50 deforms as a whole so as to escape into the gap G2. Therefore, the sealing structure 30 can suppress damage to the gasket 50 when the pressure in the internal space of the water electrolysis device E2 is increased.

[0057] Furthermore, if the elastomer forming the gasket 50 deteriorates due to an increase in pressure in the internal space of the water electrolysis apparatus E2, the gasket 50 is likely to be compressed and deformed so as to escape into the gap G2 due to the deterioration of the elastomer. In particular, in a pair of gaskets 50 provided in one space 28, when the gasket 50 with less deterioration is pushed into the gasket 50 with more deterioration, the gasket 50 with less deterioration is likely to be compressed and deformed so as to escape into the gap G2. In other words, by having the inclined surface 42b, the sealing structure 30 is able to maintain its sealing performance by compressing and deforming the deteriorated elastomer gasket 50 so that it automatically escapes into the gap G2 in response to the pressure in the internal space of the water electrolysis device E2.

[0058] Furthermore, the direction of pressure in the internal space of the water electrolysis device E2 intersects at an angle with the direction of the surface pressure between the gasket 50 and the inclined surface 42b. Therefore, when pressure (internal pressure) is applied, the surface pressure between the gasket 50 and the inclined surface 42b increases (see FIG. 7). This improves the sealing performance between the gasket 50 and the inclined surface 42b. Furthermore, when the surface pressure between the gasket 50 and the inclined surface 42b increases, the repulsive force of the gasket 50 caused by the elastomer increases. As a result, the surface pressure between the gasket 50 and the membrane layer LM increases (see FIG. 8), improving the sealing performance between the gasket 50 and the membrane layer LM.

[0059] In this way, the sealing structure 30 can suppress deterioration of the sealing property associated with an increase in pressure in the internal space of the water electrolysis apparatus E2. That is, the sealing structure 30 used in the stack 10 of the water electrolysis apparatus E2 can suppress deterioration of the sealing property when a force is applied to the gasket 50 from inside the frame to outside the frame.

[0060] In the sealing structure 30, the gasket 50 is formed from an elastomer. Therefore, in the sealing structure 30, the gasket 50 can be easily formed to have a function of being deformable toward the gap G2 when a force is applied from inside the frame toward the outside of the frame.

[0061] In the sealing structure 30, the gasket 50 has an inclined portion 55. Therefore, when a force from inside the frame toward the outside of the frame is applied to the gasket 50, the inclined portion 55 deforms so as to conform to the inclined surface 42b of the groove portion 42. Therefore, the sealing structure 30 can easily deform the gasket 50 toward the gap G2 when a force from inside the frame toward the outside of the frame is applied to the gasket 50.

[0062] In the sealing structure 30, the inclination angle A2 between the inclined portion 55 of the gasket 50 and the groove bottom 42a of the groove 42 is smaller than the inclination angle A1 between the inclined surface 42b of the groove 42 and the groove bottom 42a. In this case, when the gasket 50 deforms toward the gap G2, the gasket 50 deforms so as to expand the contact area between the corner 56 and the inclined surface 42b, starting from the contact portion between the corner 56 and the inclined surface 42b. Therefore, the sealing structure 30 can effectively increase the repulsive force of the gasket 50 caused by the elastomer as it deforms toward the gap G2. Furthermore, in the sealing structure 30, the inclined portion 55 comes into contact with the inclined surface 42b during assembly. Therefore, the sealing structure 30 can more effectively increase the repulsive force of the gasket 50 caused by the elastomer as the gasket 50 deforms toward the gap G2.

[0063] In the sealing structure 30, a film member FM is provided between the solid polymer membrane PM and the gasket 50. The surface pressure between the gasket 50 and the membrane layer LM acts to accelerate the deterioration of the solid polymer membrane PM. When the surface pressure increases with the application of a force from inside the frame to outside the frame to the gasket 50, the deterioration of the solid polymer membrane PM is further accelerated. When the film member FM is provided between the solid polymer membrane PM and the gasket 50, the surface pressure acts on the solid polymer membrane PM via the film member FM. Therefore, the sealing structure 30 can suppress the deterioration of the solid polymer membrane PM caused by the application of a force from inside the frame to outside the frame to the gasket 50.

[0064] The sealing structure 30 has a groove portion 42 formed in a groove shape as an attachment portion to which the gasket 50 can be attached. Therefore, the sealing structure 30 allows the gasket 50 to be easily positioned during assembly. Furthermore, during assembly, the sealing structure 30 can be attached and positioned in the groove 42 without applying an adhesive to the gasket 50. If an adhesive is applied to the gasket 50, there is a risk that contaminants resulting from the adhesive will be generated in the internal space of the water electrolysis apparatus E2. Therefore, by having the groove 42 as an attachment portion to which the gasket 50 can be attached, the sealing structure 30 can suppress the generation of contaminants.

[0065] As described above, the embodiments of the present disclosure have been described, but the present disclosure is not limited to the above embodiments, and various modifications, changes, and improvements are possible within the scope of the technical idea of ​​the present disclosure.

[0066] For example, the gasket 50 has a wedge-shaped cross section. However, in the sealing structure according to the present disclosure, as long as the mounting portion of the plate-shaped member has an inclined surface, the sealing member is not limited to one having a wedge-shaped cross section. The sealing member according to the present disclosure may be a gasket 250 having a rectangular cross section as shown in FIG. 10. As shown in FIG. 11, the gasket 250 is deformable toward the gap G2 when a force is applied from inside the frame to outside the frame to the sealing member having a rectangular frame shape as viewed from the stacking direction, like the gasket 50 of the embodiment, and the internal pressure is applied. When the water electrolysis apparatus E2 having the gasket 250 changes from a pre-pressurized state to an internal pressure applied state, the contact pressure between the gasket 250 and the groove 42 increases from the surface pressure in the pre-pressurized state, as shown in the graph of Fig. 12. At this time, the contact pressure between the gasket 250 and the membrane layer LM increases from the surface pressure in the pre-pressurized state, as shown in the graph of Fig. 13. The graph of the contact pressure between the gasket 250 and the groove 42 shown in Fig. 12 and the graph of the contact pressure between the gasket 250 and the membrane layer LM shown in Fig. 13 were each obtained by simulation analysis using the finite element method. In a sealing structure having a sealing member with a rectangular cross section, it is possible to easily form a sealing member that can suppress deterioration of the sealing property of the sealing structure when a force is applied from inside the frame to outside the frame to the sealing member that has a rectangular frame shape when viewed from the stacking direction.

[0067] The plate-like member 40 of the embodiment has a groove portion 42 as an attachment portion. However, the attachment portion according to the present disclosure is not limited to a groove-shaped one as long as it has an attachment surface and an inclined surface. The attachment portion according to the present disclosure may be an attachment portion 342 shown in FIG. 14. The attachment portion 342 has an attachment surface 342a and an inclined surface 42b. The inclined surface 42b of the attachment portion 342 is formed in a rectangular frame shape when viewed from the stacking direction, similar to the inclined surface 42b of the embodiment. The attachment surface 342a is rectangular and surrounded by the inclined surface 42b when viewed from the stacking direction. The attachment surface 342a is flat and connects the lower ends of the inclined surfaces 42b that face each other as a pair in a cross-sectional view along the stacking direction.

[0068] The membrane layer LM, the end walls 22, 24, the separator 26, the groove 42, and the gasket 50 of the embodiment are each rectangular or rectangular frame-shaped when viewed from the stacking direction. However, the membrane layer, the plate-shaped member, the groove-shaped mounting portion, and the seal member according to the present disclosure are not limited to being rectangular or rectangular frame-shaped when viewed from the stacking direction. The membrane layer and the plate-shaped member according to the present disclosure may be circular or elliptical when viewed from the stacking direction. The seal member and the groove-shaped mounting portion according to the present disclosure may be annular when viewed from the stacking direction. The seal member according to the present disclosure may be an O-ring.

[0069] The membrane layer LM of the embodiment has a film member FM. However, the membrane layer LM according to the present disclosure may not have a film member as shown in Fig. 15. Also, the film member according to the present disclosure may be provided separately from the membrane layer.

[0070] The film member FM of the membrane layer LM in the embodiment is provided between the solid polymer membrane PM and the gasket 50. However, the membrane layer according to the present disclosure may be the membrane layer LM5 shown in FIG. 16. The membrane layer LM5 has a solid polymer membrane PM5 formed so as to be surrounded by a sealing member (gasket 50) when viewed from the stacking direction, instead of the solid polymer membrane PM. The membrane layer LM5 has a film member FM5 provided so as to surround the edge of the solid polymer membrane PM5, instead of the film member FM. In this case, a pair of sealing members (gaskets 50) provided in the unit cell UC are arranged so as to sandwich only the film member FM5. Even in this case, the sealing member (gasket 50) has a function of sealing the space 528 capable of accommodating the unit cell UC.

[0071] The sealing structure 30 of the embodiment is used in a bipolar cell type water electrolysis apparatus E2 having a stack 10 formed by stacking a plurality of unit cells UC in a stacking direction. However, the sealing structure according to the present disclosure may also be used in a single-cell type water electrolysis apparatus 7E2 as shown in Fig. 18. Furthermore, the sealing structure according to the present disclosure may also be used in a bipolar cell type or single-cell type fuel cell. [Explanation of symbols]

[0072] E2: Water electrolysis device 10: Laminate UC: Unit cell LM: Membrane layer PM: Solid polymer membrane FM: Film material 22: End wall 22a: Port section 22b: Port section 24: End wall 24a: Port section 26: Separator 30: Sealed structure 40: Plate-shaped member 41: Edge 41a: Edge surface 42: Groove 42a: Groove bottom 42b: Inclined surface 50: Gasket (an example of a sealing material) 55: Inclined part G0: Gap G1: Gap G2: Gap

Claims

1. A sealing structure used in a stack having a plurality of unit cells stacked in a stacking direction, A sheet-like membrane layer along a plane perpendicular to the lamination direction; A plate-like member adjacent to and facing the membrane layer, an edge portion provided on an edge side of the plate-like member and having an edge surface facing the film layer; a mounting portion having a mounting surface that is concave with respect to the edge surface and an inclined surface that is inclined from the mounting surface toward the edge surface, the mounting portion having a gap between the inclined surface and the film layer; A plate-like member having a sealing member that is arranged on the opposite side of the inclined surface from the edge portion, has a frame shape adjacent to the inclined surface when viewed from the film layer side, and seals between the film layer and the plate-like member, the sealing member being deformable toward the gap when a force is applied from inside the frame toward the outside of the frame; A sealed structure having

2. The sealing structure according to claim 1 , wherein the seal member is formed from an elastomer.

3. The sealing structure according to claim 3 , wherein the seal member has a rectangular cross section.

4. The sealing structure according to claim 2 , wherein the seal member has an inclined portion opposed to the inclined surface.

5. The sealing structure according to claim 4 , wherein an inclination angle between the inclined portion and the mounting surface is smaller than an inclination angle between the inclined surface and the mounting surface.

6. The sealing structure according to claim 5 , wherein the inclined portion contacts the inclined surface during assembly.

7. The membrane layer has a solid polymer membrane, 7. The sealing structure according to claim 1, wherein a film member is provided between the solid polymer membrane and the seal member.

8. The sealing structure according to any one of claims 1 to 7, wherein the mounting portion is formed in a groove shape.

9. 9. The sealing structure according to claim 1, wherein the plate-like member is a separator provided between two of the unit cells adjacent to each other in the stacking direction.

10. The sealing structure according to any one of claims 1 to 8, wherein the plate-like member is an end wall provided at an end of the stack in the stacking direction.

11. A laminate formed by stacking a plurality of unit cells, each unit cell having a sheet-like membrane layer along a plane and a pair of current collectors provided on both sides of the membrane layer, in a stacking direction perpendicular to the plane, A laminate having the sealing structure according to any one of claims 1 to 10, wherein a plurality of the sealing structures are provided corresponding to a plurality of the unit cells.

12. A laminate according to claim 11; a first end wall provided at an end of the stack on a cathode side along the stacking direction, a first port portion for passing pure water between the stack; A second port portion for communicating oxygen between the stack and the second port portion; a first end wall having a second end wall provided at an end of the stack on an anode side along the stacking direction, the second end wall having a third port portion through which hydrogen is passed between the second end wall and the stack; A water electrolysis device comprising:

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