Electrolysis equipment

Abstract

SOLUTION: An electrolytic apparatus 200 comprises an electrolysis cell 12. The electrolysis cell 12 comprises: a film electrode structure 30 including a polymer electrolyte 40 intervening between a first electrode 42a and a second electrode 42b; and a first separator 32 and a second separator 34 between which the film electrode structure 30 is sandwiched. The electrolytic apparatus 200 further comprises a seal member 80 and a protective member 82. The protective member 82 surrounds the outer periphery of the second electrode 42b. The protective member 82 includes a first part 82a intervening between the polymer electrolyte 40 and the seal member 80 and a second part 82b intervening between the polymer electrolyte 40 and the second separator 34.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an electrolysis device for electrolyzing a fluid. [Background technology]

[0002] One type of electrolysis device known is a water electrolysis device that electrolyzes water to obtain hydrogen and oxygen (see, for example, Patent Document 1). The water electrolysis device includes an electrolysis cell. The electrolysis cell has a membrane electrode assembly and a first separator and a second separator that sandwich the membrane electrode assembly between them. The membrane electrode assembly has a first electrode, a second electrode, and an electrolyte membrane interposed between the first and second electrodes. The first electrode is either an anode or a cathode, and the second electrode is the other of the anode and the cathode.

[0003] When the electrolyte membrane is a proton conductor, electrons, protons, and oxygen are produced at the cathode, and hydrogen is produced at the anode. The hydrogen is under higher pressure than the oxygen. When the electrolyte membrane is an anion conductor, hydrogen and hydroxide ions are produced at the cathode, and oxygen, water, and electrons are produced at the anode. The oxygen is under higher pressure than the hydrogen. In this way, in a water electrolysis device, high-pressure gas is produced at either the first or second electrode. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-157213 Summary of the Invention [Problem to be solved by the invention]

[0005] In an electrolysis device, a sealing member is provided that surrounds the outer periphery of an electrode where high-pressure gas is generated and is interposed between a separator and an electrolyte membrane. In some cases, an inner circumferential side wall is provided on the inner periphery of the sealing member. In this configuration, the surface of the inner circumferential side wall that faces the electrolyte membrane may press against the electrolyte membrane. Under such circumstances, there is a concern that the electrolyte membrane may be deformed by being pressed by the inner circumferential side wall.

[0006] Furthermore, the seal member is deformed by the pressure of the high-pressure gas, and the deformed seal member presses against the electrolyte membrane, which may deform the electrolyte membrane.

[0007] The present invention aims to solve the above-mentioned problems. [Means for solving the problem]

[0008] An aspect of the present invention is an electrolysis device including an electrolysis cell having a membrane electrode assembly in which an electrolyte membrane is interposed between a first electrode and a second electrode, and a first separator and a second separator that sandwich the membrane electrode assembly between them.

[0009] The electrolysis device includes a fluid supply unit that supplies a fluid involved in the electrolytic reaction to the first electrode, a power source that applies a voltage between the first electrode and the second electrode, a sealing member that surrounds the outer periphery of the second electrode and is interposed between the electrolyte membrane and the second separator, and a protective member that surrounds the outer periphery of the second electrode. The protective member has a first portion that is interposed between the electrolyte membrane and the sealing member and a second portion that is interposed between the electrolyte membrane and the second separator. The first portion and the second portion are separate from each other. [Effects of the Invention]

[0010] The first portion of the protective member, which is interposed between the electrolyte membrane and the seal member, protects the electrolyte membrane when the seal member is deformed due to pressure from high-pressure gas, for example, thereby preventing the electrolyte membrane from being deformed. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic perspective view of an electrolysis device (first water electrolysis device) according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of the electrolysis cell taken along its diameter. [Figure 3] FIG. 3 is a cross-sectional view of a main part of an embodiment in which a protective member is provided on an electrolyte membrane so that a rubber sheet faces the electrolyte membrane and a metal sheet faces the sealing member. [Figure 4] FIG. 4 is a cross-sectional view of a main part of an embodiment in which a protective member is provided on an electrolyte membrane so that a metal sheet faces the electrolyte membrane and a rubber sheet faces the sealing member. [Figure 5] FIG. 5 is a cross-sectional view of a main part showing a state in which the seal member is deformed. [Figure 6] FIG. 6 is a cross-sectional view of a main part of an electrolysis apparatus (second water electrolysis apparatus) according to a second embodiment of the present invention. [Figure 7] FIG. 7 is a cross-sectional view of a main part showing a state in which the seal member has moved toward the outer peripheral side wall portion. DETAILED DESCRIPTION OF THE INVENTION

[0012] FIG. 1 is a schematic perspective view of an electrolysis device 200 according to the first embodiment. In the first embodiment, the electrolysis device 200 is a first water electrolysis device 10 that electrolyzes water. Therefore, the first water electrolysis device 10 will be described in detail below. However, the electrolysis device 200 is not limited to the first water electrolysis device 10 as long as it is a device that generates gas at the second electrode 42b shown in FIGS. 1 and 2 .

[0013] In the first water electrolysis device 10, water is electrolyzed, resulting in the production of a first gas at the first electrode 42a and a second gas at the second electrode 42b shown in FIG. 2. The second gas is pressurized higher than the first gas. In this specification, the second electrode 42b refers to an electrode for obtaining a high-pressure gas. For simplicity and ease of understanding, the first embodiment illustrates an example in which oxygen is produced as the first gas at the first electrode 42a and hydrogen is produced as the second gas at the second electrode 42b.

[0014] The first water electrolysis apparatus 10 includes electrolytic cells 12. As shown in Fig. 1 , in the first water electrolysis apparatus 10, a plurality of electrolytic cells 12 are stacked vertically (in the direction of arrow A) to form a stack 14. At one end (upper end) of the stack 14 in the stacking direction, a terminal plate 16a, an insulating plate 18a, and an end plate 20a are arranged from bottom to top. At the other end (lower end) of the stack 14 in the stacking direction, a terminal plate 16b, an insulating plate 18b, and an end plate 20b are arranged from top to bottom. The electrolytic cells 12 may be stacked horizontally (in the direction of arrow B).

[0015] A pipe (not shown) is connected to the end plate 20a. This pipe is provided with a back pressure mechanism (not shown) that can restrict the discharge of hydrogen from the hydrogen communication holes 38c (described later). The end plate 20a and the end plate 20b are fastened together via tie rods 22. This applies a fastening load to the multiple electrolysis cells 12.

[0016] Terminal portions 24a and 24b are provided on the sides of terminal plates 16a and 16b, respectively, so as to protrude outward in the diameter direction. Terminal portions 24a and 24b are electrically connected to a power source 28 for electrolysis via wires 26a and 26b, respectively.

[0017] As shown in FIG. 2, the electrolysis cell 12 includes a substantially disk-shaped membrane electrode assembly 30, a first separator 32, and a second separator 34. The first separator 32 and the second separator 34 sandwich the membrane electrode assembly 30 therebetween. A resin frame member 36 is disposed between the first separator 32 and the second separator 34. The resin frame member 36 surrounds the outer periphery of the membrane electrode assembly 30. A seal member 37a seals between the first separator 32 and the resin frame member 36, and a seal member 37b seals between the resin frame member 36 and the second separator 34.

[0018] Fluid supply passages 38a that communicate with each other in the stacking direction (arrow A direction) are provided at one end in the radial direction (arrow B direction) of the resin frame member 36. A fluid supply unit 90 is connected to the fluid supply passages 38a. The fluid supply unit 90 (see FIG. 1) supplies water, which is a fluid, to the fluid supply passages 38a.

[0019] A fluid discharge passage 38b is provided at the other end in the radial direction (the direction of arrow B) of the resin frame member 36, for discharging oxygen generated by the electrode reaction and unreacted water. As shown in FIG. 1, a supply joint 92a is connected to the resin frame member 36 arranged at the other end (lowest end) in the stacking direction. A fluid supply port 39a of the supply joint 92a communicates with the fluid supply passage 38a shown in FIG. 2. As shown in FIG. 1, a discharge joint 92b is connected to the resin frame member 36 arranged at one end (upper end) in the stacking direction. A fluid discharge port 39b of the discharge joint 92b communicates with the fluid discharge passage 38b shown in FIG. 2.

[0020] 2, the electrolysis cell 12 has a hydrogen communication hole 38c that penetrates the center in the radial direction along the stacking direction. Hydrogen generated by electrolysis of water flows through the hydrogen communication hole 38c. The pressure of the hydrogen is increased to, for example, 1 MPa to 80 MPa.

[0021] The membrane electrode assembly 30 includes an electrolyte membrane 40, a first electrode 42a, and a second electrode 42b. The electrolyte membrane 40, the first electrode 42a, and the second electrode 42b are sandwiched between a first power feeder 44a and a second power feeder 44b. The electrolyte membrane 40, the first electrode 42a, the second electrode 42b, the first power feeder 44a, and the second power feeder 44b are each generally ring-shaped. In the first embodiment, the first electrode 42a is an anode where an oxidation reaction occurs, and the second electrode 42b is a cathode where a reduction reaction occurs. The electrolyte membrane 40 is a proton exchange membrane through which protons can move, such as a hydrocarbon (HC)-based membrane or a fluorine-based membrane.

[0022] The space surrounded by the first separator 32, the resin frame member 36, and the electrolyte membrane 40 is a first electrode chamber 45a. A flow path forming member 46 and a first power feeder 44a are housed in the first electrode chamber 45a. The flow path forming member 46 and the first power feeder 44a are interposed between the first separator 32 and the electrolyte membrane 40. The flow path forming member 46 is sandwiched between the first separator 32 and the first power feeder 44a in the stacking direction.

[0023] The flow passage forming member 46 has an inlet protrusion 46a and an outlet protrusion 46b on the outer periphery thereof. The inlet protrusion 46a and the outlet protrusion 46b face each other in the radial direction.

[0024] A supply connection passage 50a is formed in the inlet protrusion 46a. The supply connection passage 50a communicates with the fluid supply communication hole 38a and the fluid flow path 50b. A plurality of holes 50c communicate with the fluid flow path 50b. The holes 50c open toward the first power feed body 44a. A discharge connection passage 50d is formed in the outlet protrusion 46b. The discharge connection passage 50d communicates with the fluid flow path 50b and the fluid discharge communication hole 38b.

[0025] A protective sheet member 48 is disposed between the first power supply body 44a and the first electrode 42a. The protective sheet member 48 has a plurality of through holes 48a extending in the stacking direction.

[0026] A substantially cylindrical, perforated body 52 is disposed at the radial center between the first separator 32 and the electrolyte membrane 40. The perforated body 52 has an inner cylinder 54 made of a porous material in which hydrogen through holes 38c are formed, and an outer cylinder 55 that surrounds the outer periphery of the inner cylinder 54. The space between the inner cylinder 54 and the outer cylinder 55 is sealed by O-rings 56a and 56b.

[0027] An annular step 55s is formed on the outer periphery of the outer cylinder 55 at the end surface facing the electrolyte membrane 40. The inner periphery of the protective sheet member 48 is inserted into the annular step 55s.

[0028] The space surrounded by the electrolyte membrane 40, the resin frame member 36, and the second separator 34 is the second electrode chamber 45b. The second electrode chamber 45b accommodates the second power supply body 44b and the load-applying mechanism 58. The second power supply body 44b and the load-applying mechanism 58 are interposed between the electrolyte membrane 40 and the second separator 34.

[0029] The load-applying mechanism 58 includes, for example, a conductive elastic member such as a leaf spring 60. The leaf spring 60 applies a load to the second power supply body 44b via a metal shim member 62. The load is applied in a direction that presses the second power supply body 44b toward the second electrode 42b, that is, downward in the stacking direction.

[0030] A conductive sheet 66 and an insulating sheet 68 are disposed between the second current feeder 44b and the shim member 62. The conductive sheet 66 is formed, for example, from a metal sheet with a hydrogen communication hole 38c provided approximately at the radial center. The inner and outer diameters of the conductive sheet 66 are approximately equal to the inner and outer diameters of the second current feeder 44b, respectively. The surface of the conductive sheet 66 facing the second current feeder 44b has a recess 66a. The insulating sheet 68 is housed in the recess 66a.

[0031] A cylindrical member 70 is disposed radially inward of the load-applying mechanism 58. The cylindrical member 70 is interposed between the conductive sheet 66 and the second separator 34 in the stacking direction. A hydrogen communication hole 38c is formed in the radial center of the cylindrical member 70. A hydrogen discharge passage 71 is formed in one end face of the cylindrical member 70 facing the second separator 34. The hydrogen discharge passage 71 connects the second electrode chamber 45b and the hydrogen communication hole 38c.

[0032] In the stacking direction, a sealing member 80 and a protective member 82 are interposed between the electrolyte membrane 40 and the second separator 34. The sealing member 80 is sandwiched between the protective member 82 and the second separator 34. The protective member 82 has a first portion 82a interposed between the electrolyte membrane 40 and the sealing member 80, and a second portion 82b interposed between the electrolyte membrane 40 and the second separator 34 with an outer peripheral side wall portion 84 interposed therebetween.

[0033] The first water electrolysis device 10 has an outer circumferential sidewall 84 and an inner circumferential sidewall 86. The outer circumferential sidewall 84 surrounds the seal member 80. Therefore, the inner periphery of the outer circumferential sidewall 84 faces the outer periphery of the seal member 80. The outer circumferential sidewall 84 is formed, for example, from a ring-shaped, pressure-resistant member that is separate from the second separator 34. The seal member 80 surrounds the inner circumferential sidewall 86. Therefore, the inner periphery of the seal member 80 faces the outer periphery of the inner circumferential sidewall 86. The inner circumferential sidewall 86 is, for example, an annular convex portion that protrudes downward from the lower surface of the second separator 34. In this case, the inner circumferential sidewall 86 is part of the second separator 34.

[0034] The outer peripheral side wall portion 84 may be an annular convex portion that protrudes downward from the lower surface of the second separator 34. The inner peripheral side wall portion 86 may be formed from a ring-shaped member that is separate from the second separator 34.

[0035] The outer peripheral side wall portion 84 and the inner peripheral side wall portion 86 may be provided on the same member. In this case, the member may have, for example, a ring-shaped portion separate from the second separator 34. The outer peripheral side wall portion 84 is provided at the outer peripheral end of the ring-shaped portion so as to protrude downward from the lower surface. The inner peripheral side wall portion 86 is provided at the inner peripheral end of the ring-shaped portion so as to protrude downward from the lower surface.

[0036] In either embodiment, an annular groove 88 is formed between the outer peripheral sidewall portion 84 and the inner peripheral sidewall portion 86. The seal member 80 is inserted into the annular groove 88. As shown in FIG. 2 , in the protective member 82, the inner peripheral end portion 82i of the first portion 82a is located inward of the inner peripheral end portion 86i of the inner peripheral sidewall portion 86. Furthermore, a second electrode chamber 45b surrounded by the inner peripheral sidewall portion 86 and the second separator 34 is formed inside the inner peripheral sidewall portion 86. The second electrode chamber 45b accommodates the second electrode 42b, the second power supply body 44b, the conductive sheet 66, the insulating sheet 68, the shim member 62, and the load-applying mechanism 58.

[0037] The protective member 82 is, for example, a single annular sheet. In the annular protective member 82, the inner circumferential surface of the first portion 82a is close to the outer circumferential portion 42bo of the second electrode 42b. The inner circumferential surface of the first portion 82a may abut against the outer circumferential portion 42bo of the second electrode 42b. The protective member 82 may not be interposed between the electrolyte membrane 40 and the second electrode 42b.

[0038] Suitable examples of the sheet include a metal sheet or a rubber sheet. However, the protective member 82 is not limited to a metal sheet or a rubber sheet. The protective member 82 may also be made of carbon paper.

[0039] When the first water electrolysis apparatus 10 is fabricated, the end plates 20a and 20b are fastened together via the tie rods 22 as described above. This applies a clamping load to the multiple electrolytic cells 12. When the protective member 82 is made of a metal sheet, the clamping load is reduced. This allows the clamping loads to be uniform across the multiple electrolytic cells 12.

[0040] When the protective member 82 is formed of a rubber sheet, the clamping load can be made uniform across the multiple electrolytic cells 12, as described above. Furthermore, the rubber sheet is easily compressed when the first water electrolysis device 10 is clamped. This allows for uniform pressure distribution across the surface of each of the multiple electrolytic cells 12. As a result, the cell voltage of each of the multiple electrolytic cells 12 is stabilized at a low value. Furthermore, the difference in voltage across the multiple electrolytic cells 12 is reduced.

[0041] 3 and 4, the protective member 82 may be a laminated sheet 85. A suitable example of the laminated sheet 85 is a laminate of a metal sheet 83a and a rubber sheet 83b. In this case, in the embodiment shown in FIG. 3, the rubber sheet 83b faces the electrolyte membrane 40, and the metal sheet 83a faces the sealing member 80. In the embodiment shown in FIG. 4, the metal sheet 83a faces the electrolyte membrane 40, and the rubber sheet 83b faces the sealing member 80.

[0042] In an embodiment where the rubber sheet 83b faces the electrolyte membrane 40 and the metal sheet 83a faces the seal member 80 (see FIG. 3), even if the metal sheet 83a has minute irregularities, the rubber sheet 83b deforms to fill the irregularities, so that the protective member 82 adheres tightly to the electrolyte membrane 40. Therefore, the bonding strength of the protective member 82 to the electrolyte membrane 40 is high.

[0043] In a configuration in which the metal sheet 83a faces the electrolyte membrane 40 and the rubber sheet 83b faces the sealing member 80 (see FIG. 4), the protective member 82 is also in close contact with the electrolyte membrane 40, as described above. Also, the electrolyte membrane 40 and the second separator 34 are effectively insulated from each other. Furthermore, since the rubber sheet 83b abuts against the second separator 34, if the second separator 34 is made of metal, the second separator 34 is protected from corrosion.

[0044] In the first embodiment, the inner circumferential end 82i of the protective member 82 (first portion 82a) is located inward of the inner circumferential end 86i of the inner circumferential wall portion 86. Therefore, as the protective member 82 is fastened as described above, a pressing force is applied to the protective member 82 from the lower surface of the inner circumferential wall portion 86 that faces the electrolyte membrane 40. At this time, the protective member 82 absorbs the pressing force. Therefore, the pressing force acting on the electrolyte membrane 40 is reduced, and deformation of the electrolyte membrane 40 is suppressed.

[0045] Next, the operation of the first water electrolysis device 10 will be described.

[0046] A voltage is applied from a power supply 28 to the terminal portion 24a of the terminal plate 16a and the terminal portion 24b of the terminal plate 16b shown in FIG. 1. Furthermore, water is supplied as a fluid from a fluid supply unit 90. The water flows through a fluid supply port 39a and into a fluid supply passage 38a (see FIG. 2) of the electrolysis cell 12. Within the electrolysis cell 12, the water flows through the fluid supply passage 38a and the supply connecting channel 50a and into a fluid flow passage 50b of the flow passage forming member 46. The water is then supplied to the first power supply body 44a through a plurality of holes 50c.

[0047] Water is electrolyzed at the first electrode 42a. As a result, protons, electrons, and oxygen are produced. That is, water participates in an electrode reaction (oxidation reaction) at the first electrode 42a. The protons travel through the electrolyte membrane 40 to the second electrode 42b, where they combine with electrons. As a result, hydrogen is produced. This hydrogen is discharged from the second electrode chamber 45b to the hydrogen communication hole 38c via the pores in the second power supply body 44b and the hydrogen discharge passage 71.

[0048] The back pressure mechanism restricts the discharge of hydrogen from the hydrogen communication hole 38c. Therefore, as the water electrolysis reaction progresses in the electrolysis cell 12, the generated hydrogen increases the internal pressure of the second electrode chamber 45b. As a result, the internal pressure of the second electrode chamber 45b becomes higher than the internal pressure of the first electrode chamber 45a, and the hydrogen in the hydrogen communication hole 38c is maintained at high pressure. This allows high-pressure hydrogen, which has been increased to a predetermined pressure, to be discharged from the first water electrolysis device 10. Meanwhile, oxygen generated by the electrode reaction (reduction reaction) at the first electrode 42a is entrained with unreacted water and discharged at normal pressure to the outside of the first water electrolysis device 10 via the fluid discharge communication hole 38b and the fluid discharge port 39b.

[0049] The high-pressure hydrogen in the second electrode chamber 45b flows into the annular groove 88. Therefore, as shown in Fig. 5, the seal member 80 may be pressed by the high-pressure hydrogen and pressed against the inner circumferential surface of the outer circumferential side wall portion 84. Furthermore, the seal member 80 is pressed by the high-pressure hydrogen and deformed so as to expand along the stacking direction.

[0050] As the seal member 80 deforms as described above, the lower portion of the seal member 80 facing the protective member 82 and the electrolyte membrane 40 presses against the protective member 82 so that the protective member 82 extends in a direction perpendicular to the stacking direction. Therefore, the pressing force from the seal member 80 is alleviated by the protective member 82. In this way, the protective member 82 extends from the second electrode chamber 45b, where high-pressure hydrogen is produced, to the inside of the annular groove 88 into which the high-pressure hydrogen flows. As a result, deformation of the electrolyte membrane 40 is suppressed.

[0051] Because deformation of the electrolyte membrane 40 is suppressed, an increase in the amount of high-pressure hydrogen produced at the second electrode 42b that permeates the first electrode 42a is suppressed. This prevents a decrease in the amount of hydrogen recovered through the hydrogen communication holes 38c. Furthermore, because hydrogen is prevented from interfering with the electrode reaction at the first electrode 42a, a decrease in reaction efficiency is avoided. For these reasons, sufficient amounts of hydrogen and oxygen can be obtained by electrolysis of water.

[0052] The effects of the first embodiment can be summarized as follows.

[0053] 2, the first water electrolysis device 10 according to the first embodiment includes a protective member 82 interposed between the electrolyte membrane 40 and the seal member 80. A first portion 82a of the protective member 82 prevents deformation of the electrolyte membrane 40 when hydrogen is generated at the second electrode 42b and the seal member 80 is deformed.

[0054] As a result, it is possible to prevent a decrease in the progress of the electrode reaction at the first electrode 42a or the second electrode 42b due to deformation of the electrolyte membrane 40. It is also possible to prevent a decrease in the amount of high-pressure hydrogen recovered. Therefore, sufficient amounts of hydrogen and oxygen can be obtained by electrolysis of water.

[0055] The inner circumferential surface of the protection member 82 abuts against the outer circumferential portion 42bo of the second electrode 42b.

[0056] In the electrolyte membrane 40, most of the end surface facing the seal member 80 is covered with the protective member 82. Therefore, deformation of the electrolyte membrane 40 is further suppressed.

[0057] In one embodiment, the protective member 82 is formed from a metal sheet.

[0058] In this case, the clamping load when clamping the first water electrolysis device 10 is reduced by the protective member 82. This allows the clamping loads to be uniform across the multiple electrolysis cells 12.

[0059] In one embodiment, the protective member 82 is formed from a rubber sheet.

[0060] This configuration also allows the clamping loads to be uniform across the multiple electrolytic cells 12, as described above. Furthermore, the protective member 82 made of a rubber sheet is easily compressed when the first water electrolysis device 10 is clamped. This allows for uniform pressure distribution across the surface of each of the multiple electrolytic cells 12. As a result, the cell voltage of each of the multiple electrolytic cells 12 is stabilized at a low value. Furthermore, the difference in voltage across the multiple electrolytic cells 12 is reduced.

[0061] In one embodiment, the protective member 82 has a laminated sheet 85 of a metal sheet 83a and a rubber sheet 83b.

[0062] 3, when the rubber sheet 83b faces the electrolyte membrane 40 and the metal sheet 83a faces the seal member 80, insulation is achieved between the electrolyte membrane 40 and the second separator 34. Furthermore, since the rubber sheet 83b is interposed between the metal sheet 83a and the electrolyte membrane 40, the intrusion of metal from the metal sheet 83a into the electrolyte membrane 40 is prevented.

[0063] 4, when the metal sheet 83a faces the electrolyte membrane 40 and the rubber sheet 83b faces the seal member 80, insulation is achieved between the electrolyte membrane 40 and the second separator 34. Furthermore, since the rubber sheet 83b abuts against the second separator 34, if the second separator 34 is made of metal, the second separator 34 is protected from corrosion.

[0064] The above-mentioned effects can also be obtained in the second embodiment described later. In addition, the first embodiment has the following unique effects.

[0065] The first water electrolysis apparatus 10 includes an outer circumferential sidewall 84 that faces the outer periphery of the seal member 80, and an inner circumferential sidewall 86 that faces the inner periphery of the seal member 80 and has its outer periphery surrounded by the seal member 80. An annular groove 88 is formed between the outer circumferential sidewall 84 and the inner circumferential sidewall 86. The seal member 80 is inserted into the annular groove 88. An inner circumferential end 82i of the protective member 82 is located inward of an inner circumferential end 86i of the inner circumferential sidewall 86.

[0066] When the stack 14 is fastened, the pressing force acting from the lower surface of the inner circumferential side wall portion 86 toward the electrolyte membrane 40 is absorbed by the protective member 82. Therefore, even in this case, deformation of the electrolyte membrane 40 is suppressed.

[0067] Next, a second water electrolysis apparatus 100 according to a second embodiment will be described with reference to Figure 6. The second water electrolysis apparatus 100 is an apparatus for electrolyzing water, similar to the first water electrolysis apparatus 10. For this reason, the same components as those shown in Figures 1 to 5 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0068] The second water electrolysis device 100 does not include an inner circumferential wall 86. Therefore, the seal member 80 surrounds the outer peripheral surface of the second electrode 42b. A space 102 that communicates with the second electrode chamber 45b is formed between the outer peripheral surface of the second electrode 42b and the inner circumferential surface of the outer circumferential wall 84. In the space 102, the seal member 80 is movable in the radial direction.

[0069] In the second embodiment, the inner peripheral end 82i of the protective member 82 is located more inward than the inner peripheral end 80i of the sealing member 80. That is, the inner peripheral end 82i of the protective member 82 extends into the space 102. Therefore, the upper surface of the protective member 82 is one surface that forms the space 102. The inner peripheral surface of the annular protective member 82 abuts against the outer peripheral portion of the second electrode 42b.

[0070] In the second embodiment, when high-pressure hydrogen is generated at the second electrode 42b, the high-pressure hydrogen is temporarily stored in the space 102. The high-pressure hydrogen in the space 102 presses the seal member 80 toward the outer peripheral side wall 84. As a result, as shown in FIG. 7, the seal member 80 moves toward the inner peripheral surface of the outer peripheral side wall 84 and is compressed. At this time, as in the first embodiment, the pressing force from the lower part of the seal member 80 is absorbed (reduced) by the protection member 82.

[0071] Furthermore, as the seal member 80 is deformed as described above, the exposed area of ​​the upper surface of the protective member 82 increases. Therefore, the pressure of the high-pressure hydrogen acts mainly on the upper surface of the protective member 82. This prevents the protective member 82 from peeling off from the electrolyte membrane 40. Therefore, the electrolyte membrane 40 is effectively protected by the protective member 82. In this way, even in a configuration in which the inner circumferential side wall portion 86 does not exist, providing the protective member 82 can prevent the electrolyte membrane 40 from deforming. Therefore, in the second embodiment as well, sufficient amounts of hydrogen and oxygen can be obtained by electrolysis of water.

[0072] The second embodiment has the following unique effects.

[0073] The second water electrolysis apparatus 100 includes an outer peripheral wall 84 facing the outer periphery of the seal member 80. A space 102 is formed between the outer peripheral surface of the second electrode 42b and the inner peripheral surface of the outer peripheral wall 84. The seal member 80 is movably housed in the space 102. An inner peripheral end 82i of the protection member 82 is located inward of an inner peripheral end 80i of the seal member 80.

[0074] When the high-pressure hydrogen stored in the space 102 moves the seal member 80 toward the outer peripheral side wall 84, the exposed area of ​​the upper surface of the protective member 82 increases. Therefore, the pressure of the high-pressure hydrogen acts mainly on the upper surface of the protective member 82. This prevents the protective member 82 from peeling off from the electrolyte membrane 40.

[0075] In the above-described first and second embodiments, oxygen is generated as the first gas at the first electrode 42a, and hydrogen is generated as the second gas at the second electrode 42b. However, a configuration in which hydrogen is generated as the first gas at the first electrode 42a, and oxygen is generated as the second gas at the second electrode 42b may also be used. The latter configuration will now be briefly described.

[0076] When an electrolyte membrane 40 made of an anion conductor is used, a reduction reaction occurs at the first electrode 42a, producing hydrogen and hydroxide ions from water. The hydroxide ions are transported through the electrolyte membrane 40 to the second electrode 42b. At the second electrode 42b, an oxidation reaction occurs, producing oxygen, water, and electrons from the hydroxide ions. The back pressure mechanism increases the oxygen pressure to a predetermined level. In this way, the first water electrolysis device 10 and the second water electrolysis device 100 can produce hydrogen as a first gas at the first electrode 42a and obtain oxygen as a second gas at high pressure at the second electrode 42b.

[0077] Furthermore, as described above, the electrolysis device 200 according to the present invention is not limited to the first water electrolysis device 10 and the second water electrolysis device 100 that electrolyze water. In other words, the present invention can be applied to an electrolysis device 200 that electrolyzes a substance (fluid) other than water.

[0078] The following additional notes are further disclosed regarding the above embodiment.

[0079] (Appendix 1) The electrolysis device (200) of the present disclosure includes an electrolysis cell (12) having a membrane electrode assembly (30) in which an electrolyte membrane (40) is interposed between a first electrode (42a) and a second electrode (42b), and a first separator (32) and a second separator (34) that sandwich the membrane electrode assembly. The electrolysis device also includes a fluid supply unit (90) that supplies a fluid involved in an electrolytic reaction to the first electrode (42a), a power supply (28) that applies a voltage between the first electrode and the second electrode, a seal member (80) that surrounds the outer periphery of the second electrode and is interposed between the electrolyte membrane and the second separator, and a protective member (82) that surrounds the outer periphery of the second electrode. The protective member surrounds the outer periphery of the second electrode and has a first portion (82a) that is interposed between the electrolyte membrane and the seal member and a second portion (82b) that is interposed between the electrolyte membrane and the second separator. The first portion and the second portion are separate from each other.

[0080] When the seal member is deformed by the pressure of the high-pressure gas, the protective member 82 absorbs (mitigates) the pressing force acting from the deformed seal member toward the electrolyte membrane. This suppresses deformation of the electrolyte membrane. This prevents the progress of the electrode reaction at the second electrode from being slowed down due to deformation of the electrolyte membrane. Therefore, a sufficient amount of gas can be obtained at the second electrode by electrolysis.

[0081] (Appendix 2) The electrolysis device described in Appendix 1 may include an outer circumferential side wall portion (84) facing an outer circumferential side of the sealing member, an inner circumferential side wall portion (86) facing an inner circumferential side of the sealing member and having an outer circumferential edge surrounded by the sealing member, and an annular groove (88) formed between the outer circumferential side wall portion and the inner circumferential side wall portion, the sealing member being inserted into the annular groove, and an inner circumferential end portion (82i) of the protection member being located inward of an inner circumferential end portion (86i) of the inner circumferential side wall portion.

[0082] When the electrolysis device is fastened, the pressure acting from the inner circumferential wall portion toward the electrolyte membrane is absorbed (reduced) by the protective member, which also prevents deformation of the electrolyte membrane.

[0083] (Appendix 3) The electrolysis device described in Appendix 1 may further include an outer circumferential wall portion (84) facing an outer periphery of the sealing member, and a space portion (102) formed between an outer circumferential surface of the second electrode and an inner circumferential surface of the outer circumferential wall portion, in which the sealing member is movably housed, and an inner circumferential end portion (82i) of the protection member may be located inward of an inner circumferential end portion (80i) of the sealing member.

[0084] When high-pressure gas is generated at the second electrode, the high-pressure gas in the space pushes the seal member toward the outer peripheral wall, causing the seal member to move toward the inner peripheral surface of the outer peripheral wall, increasing the exposed area of ​​the upper surface of the protective member (the surface facing the space).

[0085] Therefore, the pressure of the high-pressure gas acts mainly on the upper surface of the protective member, which prevents the protective member from peeling off from the electrolyte membrane, thereby protecting the electrolyte membrane with the protective member.

[0086] (Appendix 4) In the electrolysis device according to any one of Supplementary Notes 1 to 3, an inner circumferential surface of the protective member may abut against an outer circumferential portion (42bo) of the second electrode.

[0087] The protective member covers most of the end surface of the electrolyte membrane facing the seal member, which further suppresses deformation of the electrolyte membrane.

[0088] (Appendix 5) In the electrolysis device according to any one of Supplementary Notes 1 to 4, the protective member may be formed from a metal sheet.

[0089] child of According to this configuration, the clamping loads of the multiple electrolysis cells can be made uniform.

[0090] (Appendix 6) In the electrolysis device according to any one of Supplementary Notes 1 to 4, the protective member may be formed of a rubber sheet.

[0091] With this configuration, the clamping load can be made uniform across the multiple electrolytic cells, as described above. Furthermore, the protective member made of a rubber sheet is easily compressed when the electrolytic device is clamped. This allows for uniform pressure distribution across the surface of each of the multiple electrolytic cells. As a result, the cell voltage of each of the multiple electrolytic cells is stabilized at a low value. Furthermore, the voltage difference between each of the multiple electrolytic cells is reduced.

[0092] (Appendix 7) In the electrolysis device according to any one of Supplementary Notes 1 to 4, the protective member may include a laminated sheet (85) of a metal sheet (83a) and a rubber sheet (83b).

[0093] In an embodiment in which the rubber sheet faces the electrolyte membrane and the metal sheet faces the seal member, the electrolyte membrane and the second separator can be insulated from each other, and furthermore, the intrusion of metal from the metal sheet into the electrolyte membrane can be prevented.

[0094] Similarly, in a configuration in which the metal sheet faces the electrolyte membrane and the rubber sheet faces the sealing member, the electrolyte membrane and the second separator can be insulated from each other. Furthermore, if the second separator is made of metal, the rubber sheet protects the second separator from corrosion.

[0095] (Appendix 8) The electrolysis device according to any one of Supplementary Notes 1 to 7 may be a water electrolysis device (10, 100) that electrolyzes water supplied as the fluid, and the gas generated at the second electrode may have a higher pressure than the gas generated at the first electrode.

[0096] In this case, hydrogen and oxygen can be obtained. As described above, the electrolyte membrane is a proton conductor (H + conductor), the gas produced at the first electrode is oxygen, and the gas (high-pressure gas) produced at the second electrode is hydrogen. -conductor), the gas produced at the first electrode is hydrogen, and the gas produced at the second electrode (high-pressure gas) is oxygen.

[0097] The present invention is not limited to the above disclosure, and various configurations can be adopted without departing from the gist of the present invention. [Explanation of symbols]

[0098] 10...First water electrolysis device 12...Electrolysis cell 28...Power source 30...Membrane electrode structure 32...First separator 34...Second separator 40...Electrolyte membrane 42a...First electrode 42b... second electrode 80... sealing member 82...protective member 85...laminated sheet 83a...metal sheet 83b...rubber sheet 84...Outer peripheral side wall portion 86...Inner peripheral side wall portion 88... Annular groove 90... Fluid supply portion 100...Second water electrolysis device 200...Electrolysis device

Claims

1. An electrolysis device comprising an electrolysis cell having a membrane electrode assembly in which an electrolyte membrane is interposed between a first electrode and a second electrode, and a first separator and a second separator sandwiching the membrane electrode assembly therebetween, a fluid supply unit that supplies a fluid involved in an electrolytic reaction to the first electrode accommodated in the first electrode chamber; a power source that applies a voltage between the first electrode and the second electrode; a seal member that surrounds the outer periphery of the second electrode accommodated in the second electrode chamber and is interposed between the electrolyte membrane and the second separator; a protective member having an inner peripheral end portion surrounding an outer periphery of the second electrode in the second electrode chamber and having a first portion interposed between the electrolyte membrane and the seal member, and a second portion separate from the first portion, positioned on the outer periphery of the first portion and interposed between the electrolyte membrane and the second separator; An electrolysis device comprising:

2. 2. The electrolytic device according to claim 1, further comprising: an outer circumferential side wall portion facing an outer circumferential side of the sealing member; an inner circumferential side wall portion facing an inner circumferential side of the sealing member and having an outer circumferential edge surrounded by the sealing member; and an annular groove formed between the outer circumferential side wall portion and the inner circumferential side wall portion, wherein the sealing member is inserted into the annular groove; an inner peripheral end of the protective member is located inward of an inner peripheral end of the inner peripheral side wall portion;

3. 2. The electrolysis device according to claim 1, further comprising: an outer circumferential wall portion facing an outer periphery of the seal member; and a space portion formed between an outer circumferential surface of the second electrode and an inner circumferential surface of the outer circumferential wall portion, in which the seal member is movably housed, an inner peripheral end of the protection member is located inward of an inner peripheral end of the sealing member;

4. The electrolysis apparatus according to claim 1 , wherein an inner circumferential surface of the protection member abuts against an outer circumferential portion of the second electrode.

5. 5. The electrolysis device according to claim 1, wherein the protective member is formed from a metal sheet.

6. 5. The electrolysis device according to claim 1, wherein the protective member is formed of a rubber sheet.

7. 5. The electrolysis device according to claim 1, wherein the protective member has a laminated sheet of a metal sheet and a rubber sheet.

8. 2. The electrolysis apparatus according to claim 1, which is a water electrolysis apparatus that electrolyzes water supplied as the fluid, wherein the gas generated at the second electrode has a higher pressure than the gas generated at the first electrode.

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