Differential pressure type electrolysis device

Abstract

The invention provides a differential pressure type electrolysis device. The differential pressure electrolysis device (300) includes a resin frame member (110) joined to a peripheral edge portion (42A) of an electrolyte membrane (40A). A first member (166) is interposed between the first partition plate (32) and the resin frame member (110), and a second member (168) is interposed between the resin frame member (110) and the second partition plate (34). The differential pressure electrolysis device (300) has a positioning member (160). The positioning member (160) positions the resin frame member (110) to the first member (166) or the second member (168). However, the positioning member (160) allows the resin frame member (110) to move in the surface direction. Therefore, the electrolyte membrane bearing the gas pressure can be prevented from generating wrinkles.

Description

TECHNICAL FIELD

[0001] The present application relates to a pressure differential electrolysis device that obtains a high-pressure gas by electrolysis. BACKGROUND

[0002] As an example of the pressure differential electrolysis device, a pressure differential water electrolysis device that obtains hydrogen gas and oxygen gas by electrolysis of water is known (for example, refer to Japanese Patent Application Publication No. 2019-157213). As another example of the pressure differential electrolysis device, an electrochemical hydrogen pressure booster device can be cited, which generates high-pressure hydrogen gas at one electrode pair and generates low-pressure hydrogen gas at the other electrode pair. Such a pressure differential electrolysis device includes an electrolysis cell. The electrolysis cell has a membrane electrode structure and a first separator and a second separator that sandwich the membrane electrode structure therebetween. The membrane electrode structure has a first electrode, a second electrode, and an electrolyte membrane, in which the electrolyte membrane is interposed between the first electrode and the second electrode. The first electrode is one of an anode or a cathode, and the second electrode is the other of the anode or the cathode.

[0003] In a case where the electrolyte membrane is a proton conductor and water is supplied to the anode, electrons, protons, and oxygen gas are generated at the anode, and hydrogen gas is generated at the cathode. The pressure of the hydrogen gas is higher than the pressure of the oxygen gas. The same reaction occurs in a case where water is supplied to the cathode, but the pressure of the oxygen gas is higher than the pressure of the hydrogen gas. In contrast, in a case where the electrolyte membrane is an anion conductor and water is supplied to the cathode, hydrogen gas and hydroxide ions are generated at the cathode, and oxygen gas and electrons are generated at the anode. The pressure of the hydrogen gas is lower than the pressure of the oxygen gas. The same reaction occurs in a case where water is supplied to the anode, but the pressure of the hydrogen gas is higher than the pressure of the oxygen gas. Thus, in the pressure differential water electrolysis device, the pressure of the gas generated at one electrode is higher than the pressure of the gas generated at the other electrode. SUMMARY

[0004] The electrolyte membrane has a first surface facing the first electrode and a second surface facing the second electrode. In a case where the high-pressure gas is generated at the second electrode, the second surface is subjected to the pressure from the gas. For this reason, it can cause a wrinkle (deformation) to be generated in the electrolyte membrane. In addition, a structure in which the electrolyte membrane is joined to a resin frame member is known in a fuel cell, but in a case where this structure is applied to the pressure differential electrolysis device, it can cause the electrolyte membrane to be peeled from the resin frame member when the electrolyte membrane swells.

[0005] An object of the present application is to solve the above-described technical problem.

[0006] The present application is a differential pressure electrolysis device including an electrolysis cell having a membrane electrode structure and first and second separators, wherein the membrane electrode structure has an electrolyte membrane interposed between a first electrode and a second electrode; and the first and second separators sandwich the membrane electrode structure. In the differential pressure electrolysis device, a gas having a higher pressure than a gas obtained at the first electrode is obtained at the second electrode.

[0007] The differential pressure electrolysis device includes a resin frame member, a first member, a second member, and a positioning member, wherein the resin frame member is joined to a peripheral edge portion of the electrolyte membrane; the first member is interposed between the first separator and the resin frame member in a stacking direction of the first electrode, the electrolyte membrane, and the second electrode; the second member is interposed between the resin frame member and the second separator in the stacking direction; and the positioning member positions the resin frame member in a planar direction orthogonal to the stacking direction with respect to the first member or the second member. The positioning member allows the resin frame member to move in the planar direction.

[0008] When the electrolyte membrane expands in the planar direction, the resin frame member moves in the planar direction. Accordingly, it is possible to prevent the electrolyte membrane subjected to the gas pressure from being wrinkled (permanently deformed).

[0009] The above objects, features, and advantages will be easily understood by the following description of the embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 is a schematic perspective view of a differential pressure electrolysis device (water electrolysis device) according to an embodiment of the present application.

[0011] Figure 2 is a schematic cross-sectional view of an electrolysis cell constituting the water electrolysis device, as viewed in a radial direction.

[0012] Figure 3 is a main part cross-sectional view of a main part of the electrolysis cell, as viewed in the radial direction.

[0013] Figure 4 is a schematic plan view of a frame structure, as viewed from above in a stacking direction.

[0014] Figure 5 is a schematic plan view of another frame structure, as viewed from above in the stacking direction.

[0015] Figure 6 is a main part cross-sectional view of a main part of an electrolysis cell of a water electrolysis device according to a second embodiment, as viewed in a radial direction.

[0016] Figure 7 This is a cross-sectional view of the main parts of the electrolysis cell of the water electrolysis device according to the third embodiment, as viewed from the radial direction.

[0017] Figure 8 This is a cross-sectional view of the main parts of the electrolysis cell of the water electrolysis device according to the fourth embodiment, as viewed from the radial direction.

[0018] Figure 9 This is a cross-sectional view of the main parts of the electrolysis cell of the water electrolysis device according to the first modified example of the fourth embodiment, as viewed from the radial direction.

[0019] Figure 10 This is a cross-sectional view of the main parts of the electrolysis cell of the water electrolysis device according to the second modified example of the fourth embodiment, as viewed from the radial direction. DETAILED DESCRIPTION

[0020] The following will Figure 1 The illustrated case of stacking the electrolytic cells 12 in the vertical direction (direction of arrow A) is used as an example. Therefore, "down" and "up" refer to the downside and the upside, respectively, in the stacking direction. However, this is a temporary reference to simplify the description. The stacking direction of the pressure differential electrolysis device 300 is not limited to the up-down direction. The stacking direction of the electrolytic cells 12 may also be in the horizontal direction (direction of arrow B), which is perpendicular to the vertical direction.

[0021] Figure 1 This is a schematic perspective view of a pressure differential electrolysis device 300. In the first embodiment, the pressure differential electrolysis device 300 is a water electrolysis device 10 for electrolyzing water. Therefore, the water electrolysis device 10 will be described in detail in the first embodiment. The same applies to the second to fourth embodiments described later. However, as long as the pressure differential electrolysis device 300 is capable of Figure 2 Any device that generates gas at the second electrode 43 b shown in the figure is not limited to the water electrolysis device 10 .

[0022] In the water electrolysis device 10, the result of electrolysis of water is Figure 2 The first electrode 43a shown generates the first gas, and the second electrode 43b generates the second gas. The pressure of the second gas is higher than the pressure of the first gas. In this specification, the second electrode 43b refers to an electrode for obtaining high-pressure gas. In order to simplify the description and facilitate understanding, the following method is illustrated in the first embodiment, in which oxygen is generated as the first gas at the first electrode 43a, and hydrogen is generated as the second gas at the second electrode 43b. In this method, the first electrode 43a is an anode where an oxidation reaction occurs, and the second electrode 43b is a cathode where a reduction reaction occurs. The electrolyte membrane 40A is a proton exchange membrane in which protons can move, for example, a hydrocarbon (HC) polymer membrane or a fluorine polymer membrane.

[0023] The water electrolysis device 10 includes electrolysis cells 12. As shown in Figure 1 , in the water electrolysis device 10, a stack 14 is formed by stacking a plurality of electrolysis cells 12. At one end (upper end) in the stacking direction of the stack 14, a wiring board 16a, an insulating plate 18a, and an end plate 20a are arranged in order from below to above. At the other end (lower end) in the stacking direction of the stack 14, a wiring board 16b, an insulating plate 18b, and an end plate 20b are arranged in order from above to below.

[0024] The electrolysis cell 12 has an approximately circular shape in plan view. In this case, a face direction orthogonal to the stacking direction corresponds to a diameter direction. Therefore, the face direction will also be referred to as the radial direction hereinafter. The arrow B direction is an example of the radial direction.

[0025] A pipe not shown is connected to the end plate 20a. A back pressure mechanism not shown is provided in the pipe. The back pressure mechanism can restrict the discharge of hydrogen gas from a hydrogen communication hole 38c described later. The end plate 20a and the end plate 20b are fastened and connected by a tie rod 22. Accordingly, a fastening load acts on the plurality of electrolysis cells 12.

[0026] A terminal portion 24a and a terminal portion 24b are provided on the side of the wiring board 16a and the wiring board 16b, respectively, in a manner projecting to the outside in the diameter direction. The terminal portion 24a and the terminal portion 24b are electrically connected to a power source 28 for electrolysis by a wire 26a and a wire 26b, respectively.

[0027] As shown in Figure 2 , the electrolysis cell 12 includes a frame structure 100A including a membrane electrode structure 30A in an approximately circular plate shape, and a first separator 32 and a second separator 34. The first separator 32 and the second separator 34 sandwich the frame structure 100A therebetween. A cylindrical body 36 made of resin is disposed between the first separator 32 and the second separator 34. The cylindrical body 36 surrounds the outer periphery of the membrane electrode structure 30A. The first separator 32 and the cylindrical body 36 are sealed by a sealing member 37a, and the cylindrical body 36 and the second separator 34 are sealed by a sealing member 37b.

[0028] A fluid supply communication hole 38a that communicates with each other in the stacking direction (arrow A direction) is provided at one end in the radial direction (arrow B direction) of the cylindrical body 36. A fluid supply portion 90 is connected to the fluid supply communication hole 38a. The fluid supply portion 90 (refer to Figure 1 ) supplies water as a fluid to the fluid supply communication hole 38a.

[0029] A fluid discharge communication hole 38b is provided at the other end of the cylindrical body 36 in the radial direction (direction of arrow B), and the fluid discharge communication hole 38b is used to discharge oxygen generated by the electrode reaction and unreacted water. Figure 1 As shown in FIG. 1 , a supply connector 92a is connected to the cylindrical body 36 at the other end (lowest end) in the stacking direction. The fluid supply port 39a of the supply connector 92a is connected to the fluid supply port 39a of the cylindrical body 36. Figure 2 The fluid supply communication hole 38a is connected as shown. Figure 1 As shown in FIG. 1 , a discharge connector 92b is connected to the cylindrical body 36 at one end (the uppermost end) in the stacking direction. The fluid discharge port 39b of the discharge connector 92b is connected to the cylindrical body 36 at one end (the uppermost end) in the stacking direction. Figure 2 The fluid discharge communication hole 38b is shown in communication.

[0030] like Figure 2 As shown, the electrolytic cell 12 has a hydrogen flow hole 38c extending through the stacking direction at the radial center. Hydrogen gas generated by water electrolysis flows through the hydrogen flow hole 38c. The pressure of the hydrogen gas is increased to, for example, 1 MPa to 80 MPa.

[0031] like Figure 3 As shown in the details, the frame structure 100A includes a resin frame member 110 and a membrane electrode structure 30A supported by the resin frame member 110. The resin frame member 110 is flexible and has a certain degree of softness. The membrane electrode structure 30A includes an electrolyte membrane 40A, a first electrode 43a, and a second electrode 43b. The electrolyte membrane 40A, the first electrode 43a, and the second electrode 43b are sandwiched by a first power supply 44a and a second power supply 44b. The electrolyte membrane 40A, the first electrode 43a, the second electrode 43b, the first power supply 44a, and the second power supply 44b are each roughly annular. In the first embodiment, the electrolyte membrane 40A is formed by a single ion exchange membrane 41.

[0032] In the first embodiment, the outer diameter of the first electrode 43a is substantially equal to the outer diameter of the second electrode 43b. The outer diameter of the electrolyte membrane 40A is larger than the outer diameters of the first electrode 43a and the second electrode 43b. Therefore, the peripheral edge 42A of the electrolyte membrane 40A is exposed outwardly relative to the peripheral edges of the first electrode 43a and the second electrode 43b. The resin frame member 110 is bonded to the membrane-side bonding portion 200 of the electrolyte membrane 40A. The membrane-side bonding portion 200 is a portion of the peripheral edge 42A of the electrolyte membrane 40A and forms the bonding area between the electrolyte membrane 40A and the resin frame member 110.

[0033] The electrolyte membrane 40A has a first surface 201 facing the first electrode 43a and a second surface 202 facing the second electrode 43b. The membrane-side joint portion 200 has a first joint portion 203 formed on the first surface 201 and a second joint portion 204 formed on the second surface 202. The first joint portion 203 and the second joint portion 204 are formed in a ring shape.

[0034] A plurality of fine recesses 210 and protrusions 212 are formed in the membrane-side joint portion 200. Therefore, in the electrolyte membrane 40A, the surface roughness of the membrane-side joint portion 200 is greater than that of portions other than the membrane-side joint portion 200. In addition, the surface roughness of the second joint portion 204 is greater than that of the first joint portion 203.

[0035] Further, the membrane-side joint portion 200 can be formed, for example, by performing surface treatment on a portion of the electrolyte membrane 40A that becomes the membrane-side joint portion 200 (hereinafter referred to as a "joint preparation portion"). An example of the surface treatment is alkali treatment. Specifically, the joint preparation portion that becomes the first joint portion 203 is selectively immersed in a strong alkali such as NaOH, KOH, or Ca(OH)2. Thereby, the joint preparation portion is etched to form the first joint portion 203. Further, in order to neutralize the strong alkali remaining in the first joint portion 203, it is preferable to clean the first joint portion 203 with a strong acid. As the strong acid, H2SO4, HCl, HNO3, or the like is exemplified.

[0036] Next, the joint preparation portion that becomes the second joint portion 204 is selectively immersed in the strong alkali described above. The immersion time at this time is set to be longer than the immersion time at the time of obtaining the first joint portion 203. After that, the second joint portion 204 is cleaned with the strong acid described above. Thereby, the second joint portion 204 having a surface roughness greater than that of the first joint portion 203 is obtained.

[0037] It is also possible to form the first joint portion 203 in a plurality of ring-shaped portions concentrically. In this case, after shielding a prescribed portion of the joint preparation portion with a ring-shaped shielding material, the first surface 201 is subjected to the alkali treatment described above. The portion where the shielding material is not provided is etched, and the portion shielded by the shielding material is not etched. Thereby, a plurality of second joint portions 204 are formed on the outer periphery side of the shielding material and the inner periphery side of the shielding material, respectively. Similarly, a plurality of second joint portions 204 in a concentric circle shape can also be formed.

[0038] The relationship between the surface roughness of the first joint portion 203 and the surface roughness of the second joint portion 204 is not limited to the above-described manner. For example, the surface roughness of the second joint portion 204 can also be substantially the same as that of the first joint portion 203. In addition, it is not necessary to set the surface roughness of the membrane-side joint portion 200 to be greater than that of other portions.

[0039] The resin frame member 110 includes a first member component 120 and a second member component 130. The first member component 120 and the second member component 130 overlap in the stacking direction. An annular recess 140 is formed on the inner peripheral edge of the first member component 120 and the second member component 130 that overlap each other. The membrane side joint 200 of the electrolyte membrane 40A is inserted into the annular recess 140. Alternatively, Figure 7 Similarly, the film-side joining portion 200 is sandwiched between the flat first component component 122 and the flat second component component 132 .

[0040] The membrane-side bonding portion 200 is bonded to the resin frame member 110, for example, by an adhesive AS. Specifically, in the first component structural element 120, an adhesive AS is interposed between the first inner surface forming the annular recess 140 and the first bonding portion 203, wherein the first bonding portion 203 faces the first inner surface. Similarly, in the second component structural element 130, an adhesive AS is interposed between the second inner surface forming the annular recess 140 and the second bonding portion 204, wherein the second bonding portion 204 faces the second inner surface. When the surface roughness of the first bonding portion 203 and the second bonding portion 204 is greater than that of other portions, the first inner surface and the first bonding portion 203 are firmly bonded, and the second inner surface and the second bonding portion 204 are firmly bonded due to the anchoring effect of the adhesive AS.

[0041] like Figure 2 As shown, a space surrounded by the first separator 32, the cylindrical body 36, and the electrolyte membrane 40A is formed within the electrolytic cell 12. This space is the first electrode chamber 45a. The first electrode chamber 45a houses a flow channel forming member 46 and a first power supply 44a. The flow channel forming member 46 and the first power supply 44a are sandwiched between the first separator 32 and the electrolyte membrane 40A. The flow channel forming member 46 is sandwiched between the first separator 32 and the first power supply 44a in the stacking direction.

[0042] The flow path 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.

[0043] A supply connection channel 50a is formed in the inlet protrusion 46a. The supply connection channel 50a communicates with the fluid supply communication hole 38a and the fluid flow channel 50b. Multiple holes 50c are connected to the fluid flow channel 50b. The holes 50c open toward the first power supply element 44a. A discharge connection channel 50d is formed in the outlet protrusion 46b. The discharge connection channel 50d communicates with the fluid flow channel 50b and the fluid discharge communication hole 38b.

[0044] A protection sheet member 48 is disposed between the first power supply 44a and the first electrode 43a. The protection sheet member 48 has a plurality of through-holes 48a extending in the stacking direction.

[0045] A substantially cylindrical communication hole body 52 is disposed in the center in the radial direction between the first separator 32 and the electrolyte membrane 40A. The communication hole body 52 has an inner cylinder body 54 formed of a porous body in which the hydrogen communication hole 38c is formed, and an outer cylinder body 55 that surrounds the outer periphery of the inner cylinder body 54. The inner cylinder body 54 and the outer cylinder body 55 are sealed by O-rings 56a and 56b.

[0046] An annular stepped portion 55s is formed on the end surface facing the electrolyte membrane 40A in the outer peripheral portion of the outer cylinder body 55. The inner peripheral portion of the protection sheet member 48 is inserted into the annular stepped portion 55s.

[0047] The space surrounded by the electrolyte membrane 40A, the cylindrical body 36, and the second separator 34 is the second electrode chamber 45b. The second power supply 44b and a load application mechanism 58 are housed in the second electrode chamber 45b. In the stacking direction, the second power supply 44b and the load application mechanism 58 are interposed between the electrolyte membrane 40A and the second separator 34.

[0048] The load application mechanism 58 includes, for example, an elastic member such as a plate spring 60 that is electrically conductive. The plate spring 60 applies a load to the second power supply 44b through a gasket member 62 made of metal. The direction of application of the load is the direction in which the second power supply 44b is pressed against the second electrode 43b, and is the lower direction in the stacking direction.

[0049] An electrically conductive sheet 66 is disposed between the second power supply 44b and the gasket member 62. The electrically conductive sheet 66 is formed of, for example, a metal sheet in which a hydrogen communication hole 38c is provided substantially at the center in the radial direction. The second power supply 44b has a recessed portion 67. An insulating sheet 68 is housed in the recessed portion 67.

[0050] A cylindrical member 70 is disposed inside the load application mechanism 58 in the radial direction. The cylindrical member 70 is interposed between the electrically 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 the end surface facing the second separator 34 in the cylindrical member 70. The hydrogen discharge passage 71 communicates the second electrode chamber 45b with the hydrogen communication hole 38c.

[0051] A sealing member 80 and a pressure-resistant member 84 are interposed between the electrolyte membrane 40A and the second separator 34 in the stacking direction. In the radial direction, the pressure-resistant member 84 is located outside the sealing member 80.

[0052] Also, the resin frame member 110 bonded by the adhesive AS is bonded to the film-side joint portion 200 at a joint portion located outward of the outer peripheral side end portion 80o of the sealing member 80. However, the joint portion is not limited to this position. The joint portion can also be located outward of the outer peripheral side end portion 80o of the sealing member 80.

[0053] The electrolytic cell 12 has a through-hole 150 formed by passing through the first power supply body 44a and the second member structure element 130. In the cross section along the arrow B direction, the through-hole 150 is formed in the second member structure element 130. Figure 4 In the example shown, the through-hole 150 has the first through-hole 150a to the third through-hole 150c arranged in the circumferential direction. In the circumferential direction, the second through-hole 150b is adjacent to the first through-hole 150a, and the third through-hole 150c is adjacent to the second through-hole 150b. The separation interval of the first through-hole 150a and the second through-hole 150b is 90°, and the separation interval of the second through-hole 150b and the third through-hole 150c is also 90°. In contrast, the separation interval of the third through-hole 150c and the first through-hole 150a is 180°.

[0054] The positioning member 160 passes through each of the first through-hole 150a to the third through-hole 150c. In the first embodiment, the positioning member 160 is a positioning pin 162. In the example shown, the lower end of the positioning pin 162 is supported by the flow passage forming member 46. The upper end of the positioning pin 162 is inserted into a positioning hole 164 formed in the pressure-resistant member 84, and is thereby supported by the pressure-resistant member 84. In this structure, the flow passage forming member 46 and the pressure-resistant member 84 are a first member 166 and a second member 168 that support the positioning pin 162, respectively.

[0055] The first member 166 is not limited to the flow passage forming member 46. The first member 166 can also be the first power supply body 44a, or the protective sheet member 48. The second member 168 is not limited to the pressure-resistant member 84. The second member 168 can also be the cylindrical body 36, or the first power supply body 44a. Also, the positioning pin 162 as the positioning member 160 can be supported by one of the first member 166 or the second member 168. It is not necessary for the positioning pin 162 to be supported by both the first member 166 and the second member 168.

[0056] In the example shown, the first through-hole 150a is an elongated hole shape extending in the arrow T direction. The second through-hole 150b is an approximately circular shape. The third through-hole 150c is an elongated hole shape extending in the arrow S direction. On the other hand, the cross section of the positioning pin 162 is an approximately circular shape. The cross-sectional area in the face direction of the first through-hole 150a to the third through-hole 150c is larger than the cross-sectional area in the face direction of the positioning pin 162. Figure 4 In the example shown, the first through-hole 150a is an elongated hole shape extending in the arrow T direction. The second through-hole 150b is an approximately circular shape. The third through-hole 150c is an elongated hole shape extending in the arrow S direction. On the other hand, the cross section of the positioning pin 162 is an approximately circular shape. The cross-sectional area in the face direction of the first through-hole 150a to the third through-hole 150c is larger than the cross-sectional area in the face direction of the positioning pin 162.

[0057] Specifically, the extension length Ll in the direction of the arrow T is larger than the diameter Dl of the positioning pin 162. Therefore, in the resin frame member 110, movement in the direction of the arrow T with the positioning pin 162 and the first through-hole 150a as guides is permitted. Also, in the resin frame member 110, movement in the direction of the arrow S with the positioning pin 162 and the third through-hole 150c as guides is permitted. Also, the diameter D2 of the second through-hole 150b is larger than the diameter Dl of the positioning pin 162. Therefore, in the resin frame member 110, movement in the radial direction is permitted. In this way, the positioning pin 162 that is inserted through each of the first through-hole 150a to the third through-hole 150c permits movement of the resin frame member 110 in the planar direction.

[0058] In Figure 5 In the example shown, the separation interval of the first through-hole 150a and the second through-hole 150b, the separation interval of the second through-hole 150b and the third through-hole 150c, and the separation interval of the third through-hole 150c and the first through-hole 150a are each 120°. Also, each of the cross sections of the first through-hole 150a to the third through-hole 150c is approximately circular. The cross section of the positioning pin 162 is also approximately circular, but each of the diameters D2 of the first through-hole 150a to the third through-hole 150c is larger than the diameter Dl of the positioning pin 162. Therefore, even in this mode, the cross-sectional area in the planar direction of the first through-hole 150a to the third through-hole 150c is larger than the cross-sectional area in the planar direction of the positioning pin 162. Therefore, the positioning pin 162 that is inserted through each of the first through-hole 150a to the third through-hole 150c permits movement of the resin frame member 110 in the planar direction.

[0059] The cross-sectional shape in the planar direction of the first through-hole 150a to the third through-hole 150c may, for example, also be an elongated hole shape that extends in the radial direction. Also, in Figure 4 and Figure 5 In the resin frame member 110, the through-hole 150 is formed in the circular ring portion, but the formation site of the through-hole 150 is not limited to the circular ring portion of the resin frame member 110. For example, as shown by the dashed line in Figure 4 and Figure 5 a protruding shape portion that protrudes in the radial direction from the outer peripheral portion of the circular ring portion of the resin frame member 110 can be provided, and the through-hole 150 can be formed in the protruding shape portion.

[0060] As understood from the above, the positioning pin 162 as the positioning member 160 positions the resin frame member 110 in the planar direction with respect to the flow passage forming member 46 and the pressure resistant member 84. On the other hand, the positioning pin 162 permits movement of the resin frame member 110 in the planar direction.

[0061] Next, the operation of the water electrolysis device 10 will be described.

[0062] A voltage is applied to the terminal portion 24a of the terminal block 16a and the terminal portion 24b of the terminal block 16b from the power supply 28. Figure 1 The water is supplied as a fluid from the fluid supply portion 90. The water flows into the fluid supply connection hole 38a of the electrolysis cell 12 through the fluid supply port 39a (refer to FIG. 2). The water circulates in the fluid supply communication hole 38a and the supply connection passage 50a in the electrolysis cell 12, and flows into the fluid flow passage 50b of the flow passage forming member 46. After that, the water is supplied to the first power supply body 44a from the plurality of hole portions 50c. Figure 2

[0063] The water is electrochemically decomposed at the first electrode 43a. As a result, protons, electrons, and oxygen gas are generated. That is, the water participates in an electrode reaction (oxidation reaction) in the first electrode 43a. The protons are conducted in the electrolyte membrane 40A and move to the second electrode 43b, where they combine with the electrons. As a result, hydrogen gas is generated. The hydrogen gas is discharged from the second electrode chamber 45b to the hydrogen communication hole 38c via the fine pores of the second power supply body 44b and the hydrogen discharge passage 71.

[0064] The hydrogen gas is discharged from the hydrogen communication hole 38c by the back pressure mechanism described above. Therefore, as the electrochemical decomposition reaction of the water in the electrolysis cell 12 proceeds, the internal pressure of the second electrode chamber 45b rises by the generated hydrogen gas. As a result, the internal pressure of the second electrode chamber 45b becomes higher than that of the first electrode chamber 45a, and the hydrogen gas in the hydrogen communication hole 38c is maintained at a high pressure. In this way, high-pressure hydrogen gas that has risen to a prescribed pressure can be extracted from the water electrolysis device 10. On the other hand, the oxygen gas generated by the electrode reaction (reduction reaction) in the first electrode 43a is discharged to the outside of the water electrolysis device 10 at normal pressure together with unreacted water via the fluid discharge communication hole 38b and the fluid discharge port 39b.

[0065] The electrolyte membrane 40A swells in conjunction with the occurrence of the electrochemical decomposition reaction. In addition, the inner peripheral surface of the sealing member 80 is pressed by the high-pressure hydrogen gas in the second electrode chamber 45b. In conjunction therewith, the electrolyte membrane 40A is stretched by the lower surface of the sealing member 80 that moves outward in the radial direction. Furthermore, the second surface 202 of the electrolyte membrane 40A is subjected to pressure from the high-pressure hydrogen gas in the second electrode chamber 45b. For the above reasons, the electrolyte membrane 40A extends (diameters) outward in the radial direction.

[0066] In the case where the resin frame member 110 is positioned and fixed, the extension of the electrolyte membrane 40A outward in the radial direction is hindered by the resin frame member 110. In this case, a wrinkle can occur in the peripheral portion 42A of the electrolyte membrane 40A. That is, the electrolyte membrane 40A can be deformed. ​

[0067] In the first embodiment, as shown in Figure 4 and Figure 5 the positioning pin 162 is movable in the radial direction within the insertion hole 150. Therefore, when the electrolyte membrane 40A expands in the radial direction, the resin frame member 110 that supports the membrane-electrode structure 30A moves to the outside in the radial direction. Thus, the extension of the electrolyte membrane 40A to the outside in the radial direction is prevented from being hindered by the resin frame member 110. As a result, the generation of wrinkles in the peripheral portion 42A of the electrolyte membrane 40A is prevented. That is, the deformation of the electrolyte membrane 40A is prevented.

[0068] In addition, at the joint between the membrane-side joint portion 200 and the resin frame member 110, the membrane-side joint portion 200 and the resin frame member 110 are firmly joined based on the anchoring effect of the adhesive AS. Moreover, the joint between the membrane-side joint portion 200 and the resin frame member 110 is located at a position that is further outside than the outer peripheral end portion 80o of the seal member 80. Therefore, the high-pressure hydrogen gas is less likely to reach the joint. In other words, the high-pressure hydrogen gas is less likely to exert pressure on the adhesive AS. Based on the above reasons, the peeling of the membrane-side joint portion 200 from the resin frame member 110 is prevented. Thus, the electrolyte membrane 40A and the resin frame member 110 can move integrally.

[0069] Even if the high-pressure hydrogen gas reaches the joint between the second joint portion 204 and the second member structure element 130, the anchoring effect of the adhesive AS is good because the surface roughness of the second joint portion 204 is large. Therefore, even in this case, the second joint portion 204 is less likely to peel from the second member structure element 130.

[0070] By suppressing the deformation of the electrolyte membrane 40A in the above-described manner, the amount of the high-pressure hydrogen gas generated in the second electrode 43b that permeates to the first electrode 43a is suppressed from increasing. Therefore, the amount of the hydrogen gas recovered via the hydrogen communication hole 38c is prevented from decreasing. In addition, the hydrogen gas is prevented from hindering the electrode reaction of the first electrode 43a, and thus the reaction efficiency is prevented from decreasing. Based on the above reasons, a sufficient amount of hydrogen gas and oxygen gas can be obtained by the electrolysis of water.

[0071] The first embodiment achieves the following effects.

[0072] As shown in Figure 2 and Figure 3As shown, the water electrolysis device 10 includes a resin frame member 110, a first member 166, a second member 168, and a positioning pin 162 as a positioning member 160, wherein the resin frame member 110 is joined with the peripheral portion 42A of the electrolyte membrane 40A. The positioning pin 162 positions the resin frame member 110 in a direction orthogonal to the stacking direction (radial direction) with respect to the first member 166 or the second member 168. In this structure, the positioning pin 162 allows the resin frame member 110 to move in the direction (radial direction). Further, in Figure 2 In the illustrated manner, the first member 166 is the flow passage forming member 46, and the second member 168 is the pressure resistant member 84.

[0073] When the electrolyte membrane 40A swells to the outside in the radial direction during operation of the water electrolysis device 10, the resin frame member 110 moves to the outside in the radial direction. When the electrolyte membrane 40A extends to the outside in the radial direction by receiving pressure in the stacking direction from the high-pressure hydrogen gas generated at the second electrode 43b, the resin frame member 110 also moves to the outside in the radial direction.

[0074] As described above, in the above-described structure, when the electrolyte membrane 40A extends to the outside in the radial direction, the resin frame member 110 moves to the outside in the radial direction. Accordingly, it is possible to prevent the electrolyte membrane 40A, which receives pressure from the high-pressure hydrogen gas, from being wrinkled (deformed).

[0075] As Figure 4 and Figure 5 As shown, the resin frame member 110 has insertion holes 150 (first to third insertion holes 150a to 150c) into which the positioning pins 162 are inserted. The cross-sectional area of the insertion holes 150 in the radial direction is larger than the cross-sectional area of the positioning pins 162 in the radial direction.

[0076] Therefore, it is easy to move the resin frame member 110 in the radial direction with respect to the positioning pins 162.

[0077] As Figure 2 As shown, the electrolytic cell 12 includes a sealing member 80 that surrounds the outer periphery of the second electrode 43b and is interposed between the resin frame member 110 and the second separator 34 in the stacking direction. The peripheral portion 42A of the electrolyte membrane 40A and the resin frame member 110 are joined at a joining portion by an adhesive AS. The joining portion is located at a position further to the outside than the outer peripheral side end portion 80o of the sealing member 80.

[0078] On the inner side of the sealing member 80, the high-pressure hydrogen gas generated at the second electrode 43b is blocked by the sealing member 80. Therefore, it is possible to prevent the high-pressure hydrogen gas from reaching the joining portion. Therefore, it is also possible to prevent the high-pressure hydrogen gas from pressing the adhesive AS. Accordingly, it is possible to prevent the electrolyte membrane 40A from being peeled from the resin frame member 110 due to the adhesive AS receiving pressure from the gas.

[0079] The electrolyte membrane 40A has a membrane-side bonding portion 200, and the resin frame member 110 is bonded to the membrane-side bonding portion 200 via an adhesive AS. In the electrolyte membrane 40A, the surface roughness of the membrane-side bonding portion 200 is greater than that of portions other than the membrane-side bonding portion 200.

[0080] Since the surface roughness of the membrane-side joining portion 200 is large, the membrane-side joining portion 200 and the resin frame member 110 are firmly joined by the anchoring effect of the adhesive AS. That is, it is possible to further prevent the electrolyte membrane 40A from being peeled off from the resin frame member 110.

[0081] The electrolyte membrane 40A has a first surface 201 facing the first electrode 43a and a second surface 202 facing the second electrode 43b. The membrane-side joint 200 has a first joint 203 formed on the first surface 201 and a second joint 204 formed on the second surface 202. In this structure, the surface roughness of the second joint 204 is greater than that of the first joint 203.

[0082] In this structure, the adhesive AS has a strong anchoring effect on the second surface 202 facing the second electrode 43b. Therefore, the second surface 202 can be firmly bonded to the resin frame member 110. In other words, it is possible to further prevent the electrolyte membrane 40A from peeling off from the resin frame member 110. Furthermore, by reducing the surface roughness of the first surface 201, it is possible to prevent the thickness of the membrane-side bonding portion 200 in the stacking direction from being too small.

[0083] The above-described effects can also be obtained in the second to fourth embodiments described below.

[0084] Next, refer to Figure 6 The second embodiment is described. Figure 1-5 The same components as those shown are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0085] like Figure 6 As shown, in the second embodiment, the electrolytic cell 12 includes a frame structure 100B. The frame structure 100B includes a membrane electrode assembly 30A and a resin frame member 111. In the membrane electrode assembly 30A, the peripheral edge 42A of the electrolyte membrane 40A is exposed from the peripheral edges of the first electrode 43a and the second electrode 43b.

[0086] The electrolyte membrane 40A has a first surface 201 facing the first electrode 43a and a second surface 202 facing the second electrode 43b. Figure 6In the illustrated manner, the membrane-side joint portion 200 is only the first joint portion 203 formed on the first surface 201. Although not necessarily required, it is preferable that the surface roughness of the first joint portion 203 be greater than that of the portion other than the first joint portion 203, as in the first embodiment.

[0087] As Figure 6 illustrated, in the second embodiment, the resin frame member 111 is formed of a single component structural element 121. In Figure 6 the illustrated manner, the resin frame member 111 is disposed below the electrolyte membrane 40A in the stacking direction. In this state, the portion of the inner edge portion of the resin frame member 111 that faces the first joint portion 203 of the electrolyte membrane 40A is joined to the first joint portion 203 by the adhesive AS. It is preferable that the joint portion be located at a position that is outward of the outer peripheral side end portion 80o of the seal member 80.

[0088] In this structure, high-pressure hydrogen gas generated at the second electrode 43b is difficult to reach the outer periphery of the seal member 80, but even if it is assumed that high-pressure hydrogen gas reaches the outer periphery of the seal member 80, the adhesive AS is not subjected to the pressure of the high-pressure hydrogen gas at the second surface 202. This is because there is no joint portion of the resin frame member 111 at the second surface 202.

[0089] However, in contrast to the Figure 6 illustrated manner, the membrane-side joint portion 200 can be provided as only the second joint portion 204 formed on the second surface 202 (see Figure 3 ). In this structure, the resin frame member 111 (component structural element 121) is disposed above the electrolyte membrane 40A in the stacking direction. In addition, the portion of the inner edge portion of the resin frame member 111 that faces the second joint portion 204 of the electrolyte membrane 40A is joined to the second joint portion 204 by the adhesive AS.

[0090] Even in this manner, it is preferable that the joint portion be located at a position that is outward of the outer peripheral side end portion 80o of the seal member 80. As described above, this is because, since high-pressure hydrogen gas generated at the second electrode 43b is difficult to reach the outer periphery of the seal member 80, the adhesive AS can be prevented from being subjected to the pressure of the high-pressure hydrogen gas.

[0091] As with Figure 3-5 the second embodiment, the through-hole 150 (first through-hole 150a to third through-hole 150c) is formed at a position of the resin frame member 111 that is outward of the joint portion. The positioning pin 162 is inserted through each of the first through-hole 150a to third through-hole 150c.

[0092] In the second embodiment, the structure other than the above-mentioned structure is the same as that of the first embodiment. In addition, the operation of the water electrolysis device 10 is also the same as that of the first embodiment. Therefore, the description of the structure and operation other than the above-mentioned structure will be omitted.

[0093] The second embodiment achieves the following effects.

[0094] The electrolyte membrane 40A has a first surface 201 facing the first electrode 43a and a second surface 202 facing the second electrode 43b. The resin frame member 111 is bonded to only one of the first surface 201 (first bonding portion 203) and the second surface 202 (second bonding portion 204).

[0095] like Figure 3 As shown, the resin frame member 110, which is bonded to both the first surface 201 (first bonding portion 203) and the second surface 202 (second bonding portion 204), includes a first component component 120 bonded to the first surface 201 and a second component component 130 bonded to the second surface 202. In contrast, in the second embodiment, the resin frame member 111 can be formed by only one of the component component 121 bonded to the first surface 201 (first bonding portion 203) and the component component 121 bonded to the second surface 202 (second bonding portion 204). Therefore, the number of component components 121 constituting the resin frame member 111 can be reduced. Consequently, the structure of the electrolytic cell 12 is simplified.

[0096] Next, refer to Figure 7 The third embodiment is described. Figure 1-6 The same components as those shown are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0097] like Figure 7 As shown, in the third embodiment, the electrolytic cell 12 includes a frame structure 100C. The frame structure 100C includes a membrane electrode assembly 30C and a resin frame member 112. The membrane electrode assembly 30C includes an electrolyte membrane 40C, a first electrode 43a, and a second electrode 43b.

[0098] The electrolyte membrane 40C includes a first ion exchange membrane 41a, a second ion exchange membrane 41b, and a support membrane 41c. The first ion exchange membrane 41a is in contact with the first electrode 43a. The second ion exchange membrane 41b is in contact with the second electrode 43b. The support membrane 41c is interposed between the first ion exchange membrane 41a and the second ion exchange membrane 41b. Therefore, the first ion exchange membrane 41a is interposed between the first electrode 43a and the support membrane 41c, and the second ion exchange membrane 41b is interposed between the support membrane 41c and the second electrode 43b.

[0099] The first ion exchange membrane 41a is a proton-conducting proton exchange membrane, such as a hydrocarbon (HC) polymer membrane or a fluorine polymer membrane. The polymer that is the material of the first ion exchange membrane 41a has a functional group that participates in proton conduction. In the case of a fluorine polymer, the functional group is a sulfonic acid group.

[0100] The second ion exchange membrane 41b is formed of the same material as the first ion exchange membrane 41a. In the second ion exchange membrane 41b, the concentration of the functional group that participates in proton conduction can be the same as that of the first ion exchange membrane 41a, but is preferably higher than that of the first ion exchange membrane 41a.

[0101] The support membrane 41c is softer than the first ion exchange membrane 41a and the second ion exchange membrane 41b, and is a flexible membrane. Therefore, the support membrane 41c has a higher tensile strength than the first ion exchange membrane 41a and the second ion exchange membrane 41b. As an example of a suitable material for such a support membrane 41c, expanded polytetrafluoroethylene (ePTFE) is given. However, the material of the support membrane 41c is not limited to ePTFE.

[0102] The functional group that has moved from the first ion exchange membrane 41a and the second ion exchange membrane 41b, respectively, is incorporated in the polymer that is the material of the support membrane 41c. Therefore, proton conduction also occurs in the support membrane 41c. In the case where the concentration of the functional group in the second ion exchange membrane 41b is higher than that in the first ion exchange membrane 41a, the concentration of the functional group in the support membrane 41c decreases in the stacking direction as it moves from the second ion exchange membrane 41b toward the first ion exchange membrane 41a. That is, a concentration gradient of the functional group is formed in the support membrane 41c.

[0103] The peripheral portion 42C of the support membrane 41c is exposed to the outside of each of the peripheral portions of the first electrode 43a, the first ion exchange membrane 41a, the second ion exchange membrane 41b, and the second electrode 43b. The first surface 205 in the electrolyte membrane 40C is a surface in the support membrane 41c that faces the first electrode 43a and is joined to the first ion exchange membrane 41a. The second surface 206 in the electrolyte membrane 40C is a surface in the support membrane 41c that faces the second electrode 43b and is joined to the second ion exchange membrane 41b. The membrane-side joint portion 200 of the electrolyte membrane 40C is formed in the support membrane 41c. The support membrane 41c is joined to the first ion exchange membrane 41a at the first surface 205 and is joined to the second ion exchange membrane 41b at the second surface 206. Figure 7 In the illustrated manner, the support membrane 41c has a first joint portion 207 formed at the first surface 205 and a second joint portion 208 formed at the second surface 206. Although not necessary, the surface roughness of the first joint portion 207 can be made larger than that of the portion other than the first joint portion 207, as in the first embodiment.

[0104] The resin frame member 112 has a first member structure element 122 and a second member structure element 132. The first member structure element 122 is joined to the first joining portion 207 (the first surface 205) in a range from the inner periphery to the outer periphery by the adhesive AS. The second member structure element 132 is joined to the second joining portion 208 (the second surface 206) in a range from the inner periphery to the outer periphery by the adhesive AS. Instead of this, the resin frame member 112 can be joined to the peripheral edge portion 42C of the support film 41c in a range from the inner periphery to the outer periphery by the adhesive AS. Figure 3 Similarly, an annular recessed portion 140 is formed in the inner peripheral edge portions of the first member structure element 122 and the second member structure element 132, and the peripheral edge portion 42C of the support film 41c is inserted into the annular recessed portion 140.

[0105] In the third embodiment, the lower portion of the sealing member 80 is in abutment with the second surface 206 of the support film 41c. Further, it is preferable that the joining portion of the resin frame member 112 to the support film 41c be located at a position outward of the outer peripheral side end portion 80o of the sealing member 80. As described above, this is because the high-pressure hydrogen gas generated at the second electrode 43b is difficult to reach the outer periphery of the sealing member 80, and the adhesive AS of the second joining portion 208 can be prevented from bearing the pressure of the high-pressure hydrogen gas.

[0106] An example of a procedure for obtaining such an electrolyte membrane 40C will be briefly described. First, the first electrode 43a is formed on one end surface of the first ion exchange membrane 41a. On the other hand, the second electrode 43b is formed on one end surface of the second ion exchange membrane 41b. Further, the resin frame member 112 is joined to the peripheral edge portion 42C of the support film 41c having a larger area than the first ion exchange membrane 41a and the second ion exchange membrane 41b by the adhesive AS.

[0107] Next, the support film 41c is laminated on the other end surface of the first ion exchange membrane 41a. In the support film 41c, the surface facing the other end surface of the first ion exchange membrane 41a is the first surface 205. Further, the other end surface of the second ion exchange membrane 41b is laminated on the support film 41c. In the support film 41c, the surface facing the other end surface of the second ion exchange membrane 41b is the second surface 206.

[0108] As described above, the laminate of the first electrode 43a, the first ion exchange membrane 41a, the support film 41c, the second ion exchange membrane 41b, and the second electrode 43b is obtained. Next, heat and pressure are applied to the laminate. By this heat and pressure, the respective membranes from the first electrode 43a to the second electrode 43b are firmly joined, and the first member structure element 122 and the second member structure element 132 are firmly joined to the peripheral edge portion 42C of the support film 41c. Further, a part of the functional groups of the first ion exchange membrane 41a moves to the support film 41c, and a part of the functional groups of the second ion exchange membrane 41b moves to the support film 41c.

[0109] Instead of this, the resin frame member 112 can be joined to the peripheral edge portion 42C of the support film 41c after the laminate is formed using the support film 41c that is not joined to the resin frame member 112. Alternatively, the resin frame member 112 can be joined to the peripheral edge portion 42C of the support film 41c after the laminate is subjected to heat pressing.

[0110] With Figure 3-5 Also, the resin frame member 112 is formed with through-holes 150 (first through-hole 150a to third through-hole 150c) at positions that are outside the joining portions. The positioning pins 162 are inserted through the first through-hole 150a to the third through-hole 150c.

[0111] In the third embodiment, the structures other than the above-described structure are the same as those of the first embodiment. Also, the operation of the water electrolysis device 10 is the same as that of the first embodiment. Therefore, the description of the structures and the operation other than the above-described structure and operation will be omitted.

[0112] The third embodiment achieves the following effects.

[0113] The electrolyte membrane 40C has a first ion exchange membrane 41a, a second ion exchange membrane 41b, and a support film 41c, wherein the first ion exchange membrane 41a is in contact with the first electrode 43a, the second ion exchange membrane 41b is in contact with the second electrode 43b, and the support film 41c is interposed between the first ion exchange membrane 41a and the second ion exchange membrane 41b. The support film 41c has a tensile strength that is greater than those of the first ion exchange membrane 41a and the second ion exchange membrane 41b. The resin frame member 112 is joined to the peripheral edge portion 42C of such a support film 41c.

[0114] Since the support film 41c has a greater tensile strength, the deformation of the electrolyte membrane 40C due to the pressure of the high-pressure hydrogen gas can be further suppressed.

[0115] Preferably, in one mode, the material of the support film 41c is ePTFE (expanded polytetrafluoroethylene) having a functional group. In addition, the functional group is the same group as the functional group that participates in ion exchange in the first ion exchange membrane 41a and the second ion exchange membrane 41b.

[0116] The ePTFE has a good tensile strength. Also, in the third embodiment, the ePTFE has a functional group that participates in ion conduction. Therefore, ion conduction between the first electrode 43a and the second electrode 43b via the electrolyte membrane 40C can reliably occur.

[0117] In a preferred mode, the concentration of the functional group of the second ion exchange membrane 41b is higher than that of the first ion exchange membrane 41a.

[0118] Second ion exchange membrane 41b contains water. When the concentration of functional groups involved in ion exchange is high, second ion exchange membrane 41b can retain a large amount of water. Therefore, even when second ion exchange membrane 41b is pressed by high-pressure hydrogen, second ion exchange membrane 41b can retain a certain amount of water. Therefore, even after high-pressure hydrogen is generated in second electrode 43b, sufficient ion conduction occurs in second ion exchange membrane 41b.

[0119] Next, refer to Figure 8 The fourth embodiment is described. Figure 1-7 The same components as those shown are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0120] like Figure 8 As shown, in the fourth embodiment, the electrolytic cell 12 includes a frame structure 100D. The frame structure 100D includes a membrane electrode assembly 30D and a resin frame member 113. The membrane electrode assembly 30D includes an electrolyte membrane 40D.

[0121] Similar to the electrolyte membrane 40C, the electrolyte membrane 40D includes a first ion exchange membrane 41a, a second ion exchange membrane 41b, and a support membrane 41c. A preferred example of the material of the support membrane 41c is ePTFE, similar to the third embodiment. In the fourth embodiment, the concentration of functional groups involved in proton conduction in the second ion exchange membrane 41b is preferably higher than that in the first ion exchange membrane 41a.

[0122] The second ion exchange membrane 41b has an area larger than that of the first ion exchange membrane 41a and is substantially equal to that of the support membrane 41c. Therefore, the peripheral edge 42C of the support membrane 41c and the peripheral edge 42E of the second ion exchange membrane 41b are exposed outside the peripheral edges of the first electrode 43a, the first ion exchange membrane 41a, and the second electrode 43b.

[0123] The supporting membrane 41c constituting the electrolyte membrane 40D has a first surface 205 and a second surface 206. The first surface 205 faces the first electrode 43a and the first ion exchange membrane 41a, and the second surface 206 faces the second electrode 43b and the second ion exchange membrane 41b. Figure 8 In the illustrated embodiment, the film-side bonding portion 200 is only the first bonding portion 207 formed on the first surface 205. Although not essential, it is preferable that the surface roughness of the first bonding portion 207 be greater than that of portions other than the first bonding portion 207, as in the first embodiment.

[0124] In the fourth embodiment, similarly to the second embodiment, the resin frame member 113 is formed of a single component element 123. Figure 8In the illustrated embodiment, the resin frame member 113 is positioned below the electrolyte membrane 40D in the stacking direction. In this state, the inner edge of the resin frame member 113, facing the first bonding portion 207 of the electrolyte membrane 40D, is bonded to the first bonding portion 207 using an adhesive AS. The bonded portion is preferably located outside the outer peripheral end 80o of the sealing member 80. Furthermore, in the fourth embodiment, the lower portion of the sealing member 80 abuts the upper surface of the peripheral edge 42E of the second ion exchange membrane 41b.

[0125] and Figure 8 Contrary to the embodiment shown, the membrane-side bonding portion 200 may be provided as only the second bonding portion 208 formed on the second surface 206 of the support film 41c (see FIG. Figure 7 In this structure, the resin frame member 113 is positioned above the support film 41c in the stacking direction. Furthermore, the inner edge of the resin frame member 113, which faces the second bonding portion 208 of the support film 41c, is bonded to the second bonding portion 208 via an adhesive AS. In this embodiment, the bonding portion is also preferably located outside the outer peripheral end 80o of the sealing member 80.

[0126] Alternatively, you can also Figure 7 Similarly, the areas of the first ion exchange membrane 41a and the second ion exchange membrane 41b are made substantially equal, and the peripheral edge portion 42C of the support membrane 41c is exposed from the peripheral edges of the first electrode 43a, the first ion exchange membrane 41a, the second ion exchange membrane 41b, and the second electrode 43b. The lower portion of the sealing member 80 abuts against the second surface 206 of the peripheral edge portion 42C of the support membrane 41c.

[0127] Alternatively, you can Figure 9 As shown in the first modification, the electrolyte membrane 40E is formed by making the area of ​​the first ion exchange membrane 41a slightly smaller than the area of ​​the second ion exchange membrane 41b. In this case, a membrane electrode assembly 30E including the electrolyte membrane 40E and a frame structure 100E including the membrane electrode assembly 30E are formed.

[0128] The first ion exchange membrane 41a has a peripheral portion 42D exposed from the peripheral portions of the first electrode 43a and the second electrode 43b. The peripheral portion 42D of the first ion exchange membrane 41a, the peripheral portion 42C of the support membrane 41c, and the peripheral portion 42E of the second ion exchange membrane 41b overlap in the stacking direction.

[0129] Alternatively, you can Figure 10As shown in the second modification of the first embodiment, the electrolyte membrane 40F is configured such that the area of the first ion exchange membrane 41a is larger than the area of the second ion exchange membrane 41b and slightly smaller than the support membrane 41c. In this case, the membrane electrode structure 30F having the electrolyte membrane 40F and the frame structure 100F having the membrane electrode structure 30F are configured.

[0130] In this structure, the peripheral portion 42D of the first ion exchange membrane 41a and the peripheral portion 42C of the support membrane 41c overlap in the stacking direction. The lower portion of the sealing member 80 abuts against the second surface 206 of the peripheral portion 42C of the support membrane 41c.

[0131] Also, the resin frame member 112 shown in FIG. 12 can be joined to the electrolyte membrane 40E or the electrolyte membrane 40F. Figure 7

[0132] As shown in FIG. 13, the resin frame member 113 is formed of a resin material. The resin frame member 113 is formed in a rectangular shape. The resin frame member 113 is formed of a single piece. The resin frame member 113 is formed of a single piece. The resin frame member 113 is formed of a single piece. Figure 3-5 Also, as shown in FIG. 13, the resin frame member 113 is formed with through-holes 150 (first through-hole 150a to third through-hole 150c) at positions outward of the joining portions. The positioning pins 162 are inserted through the first through-hole 150a to the third through-hole 150c.

[0133] In the fourth embodiment, the structures other than the above-described structures are the same as those of the first embodiment. Also, the operation of the water electrolysis device 10 is the same as that of the first embodiment. Therefore, the description of the structures and the operation other than the above-described structures and the operation is omitted.

[0134] As with the electrolyte membrane 40C in the third embodiment, according to the fourth embodiment, the effect of further suppressing the deformation of the electrolyte membrane 40D due to the pressure of the high-pressure hydrogen gas can be obtained. Also, in the fourth embodiment, the resin frame member 113 can be configured by either the member structure element 123 joined to the first surface 205 (the first joining portion 207) or the member structure element 123 joined to the second surface 206 (the second joining portion 208). Therefore, the number of members configuring the resin frame member 113 can be reduced. Thus, the structure of the water electrolysis device 10 can be simplified.

[0135] In the above-described first embodiment to the fourth embodiment, the case where the oxygen gas is generated as the first gas at the first electrode 43a and the hydrogen gas is generated as the second gas at the second electrode 43b is exemplified. However, the case where the hydrogen gas is generated as the first gas at the first electrode 43a and the oxygen gas is generated as the second gas at the second electrode 43b can be exemplified. The case is briefly described. In addition, as with the above-described case, the electrolyte membranes 40A, 40C, and 40D are proton conductors.

[0136] ​In this mode, the first electrode 43a is set as a cathode and the second electrode 43b is set as an anode, and water is supplied to the first electrode 43a as a cathode. The water permeates the electrolyte membranes 40A, 40C, 40D and contacts the second electrode 43b as an anode. In the second electrode 43b, protons, oxygen gas, and electrons are generated by the electrolysis of water. The protons move to the first electrode 43a as a cathode via the electrolyte membranes 40A, 40C, 40D. In the first electrode 43a, the protons combine with the electrons to generate hydrogen gas. The pressure of the oxygen gas is raised to a predetermined pressure by the back pressure mechanism. That is, oxygen gas having a higher pressure than hydrogen gas is obtained in the second electrode 43b.

[0137] In the above-described first to fourth embodiments, the mode in which the material of the electrolyte membranes 40A, 40C, 40D is a proton conductor is exemplified. However, the material of the electrolyte membranes 40A, 40C, 40D can also be an anion conductor. This mode will be briefly described.

[0138] In the case where the electrolyte membranes 40A, 40C, 40D using an anion conductor as a material and the first electrode 43a is set as a cathode and water is supplied to the first electrode 43a, in the first electrode 43a (cathode), a reduction reaction of generating hydrogen gas and hydroxide ions from water occurs. The hydroxide ions are conducted in the electrolyte membranes 40A, 40C, 40D and move to the second electrode 43b as an anode. In the second electrode 43b (anode), an oxidation reaction of generating oxygen gas, water, and electrons from the hydroxide ions occurs. The pressure of the oxygen gas is raised to a predetermined pressure by the back pressure mechanism. That is, oxygen gas having a higher pressure than hydrogen gas can be obtained.

[0139] In contrast, in the case where the first electrode 43a is set as an anode and water is supplied to the first electrode 43a, the water permeates the electrolyte membranes 40A, 40C, 40D and contacts the second electrode 43b as a cathode. In the second electrode 43b, a reduction reaction of generating hydrogen gas and hydroxide ions from water occurs. The hydroxide ions are conducted in the electrolyte membranes 40A, 40C, 40D and move to the second electrode 43b as a cathode. In the second electrode 43b (cathode), an oxidation reaction of generating oxygen gas, water, and electrons from the hydroxide ions occurs. The pressure of the hydrogen gas is raised to a predetermined pressure by the back pressure mechanism. That is, hydrogen gas having a higher pressure than oxygen gas is obtained.

[0140] Further, as described above, the pressure difference type electrolysis device 300 is not limited to the water electrolysis device 10 that electrolyzes water. That is, the present application can be applied to the pressure difference type electrolysis device 300 that electrolyzes a substance (fluid) other than water.

[0141] The following notes are also disclosed with respect to the above-described embodiments.

[0142] (Note 1) The differential pressure electrolysis device (300) of the present application includes an electrolysis cell (12) having a membrane electrode structure (30A, 30C, 30D) and a first separator (32) and a second separator (34), wherein the membrane electrode structure has an electrolyte membrane (40A, 40C, 40D) interposed between a first electrode (43a) and a second electrode (43b), and the first separator and the second separator sandwich the membrane electrode structure between each other, and a gas having a higher pressure than a gas obtained at the first electrode is obtained at the second electrode. The differential pressure electrolysis device includes a resin frame member (110-113), a first member (166), a second member (168), and a positioning member (160), wherein the resin frame member is joined to a peripheral edge portion (42A, 42C) of the electrolyte membrane; the first member is interposed between the first separator and the resin frame member in a stacking direction of the first electrode, the electrolyte membrane, and the second electrode; the second member is interposed between the resin frame member and the second separator in the stacking direction; and the positioning member positions the resin frame member to the first member or the second member in a planar direction orthogonal to the stacking direction. The positioning member allows the resin frame member to move in the planar direction.

[0143] In this structure, the resin frame member supports the electrolyte membrane. In addition, when the electrolyte membrane swells in the planar direction orthogonal to the stacking direction during operation of the differential pressure electrolysis device, the resin frame member can move in the planar direction. As with the electrolyte membrane extending in the planar direction when it receives a pressure in the stacking direction from the gas generated at the second electrode, the resin frame member can move in the planar direction. As described above, in the case where the electrolyte membrane expands in the planar direction, the resin frame member moves in the planar direction. Accordingly, it is possible to prevent the electrolyte membrane receiving the pressure of the gas from being wrinkled (permanently deformed).

[0144] (Note 2) In the differential pressure electrolysis device described in Note 1, the resin frame member can have a through-hole (150) for the positioning member to be inserted through, and a cross-sectional area of the through-hole in the planar direction can be larger than a cross-sectional area of the positioning member in the planar direction.

[0145] According to this structure, it is easy to move the resin frame member in the planar direction with respect to the positioning member.

[0146] (Note 3) In the differential pressure electrolysis device described in Note 1 or 2, the electrolyte membrane can have a first surface (201, 205) facing the first electrode and a second surface (202, 206) facing the second electrode, and the resin frame member can be joined to only one of the first surface or the second surface.

[0147] Since the resin frame member is joined to either the first surface or the second surface, the number of resin frame members can be reduced. Thus, the structure is simplified.

[0148] (Embodiment 4) In the differential pressure type electrolytic device according to any one of Embodiments 1 to 3, the differential pressure type electrolytic device can further include a sealing member (80) that surrounds the outer periphery of the second electrode and is interposed between the resin frame member and the second separator in the stacking direction, and an adhesive (AS) that joins the peripheral edge portion of the electrolyte membrane to the resin frame member, and a joining portion of the resin frame member to the electrolyte membrane joined by the adhesive can be located outward of an outer peripheral side end portion (80o) of the sealing member.

[0149] The inside of the sealing member is made high pressure by the gas generated at the second electrode. In contrast, on the outside of the sealing member, the gas is blocked by the sealing member and thus is prevented from becoming high pressure. According to the above structure, the joining portion is prevented from being located on the inside of the sealing member that becomes high pressure. Thus, the electrolyte membrane can be prevented from being peeled from the resin frame member due to the pressure of the gas being received by the adhesive.

[0150] (Embodiment 5) In the differential pressure type electrolytic device according to any one of Embodiments 1 to 4, the differential pressure type electrolytic device can further include an adhesive (AS) that joins the peripheral edge portion of the electrolyte membrane to the resin frame member, and the electrolyte membrane can have a membrane-side joining portion (200) that is joined to the resin frame member by the adhesive, and a surface roughness of the membrane-side joining portion can be greater than a surface roughness of a portion other than the membrane-side joining portion in the electrolyte membrane.

[0151] Since the surface roughness of the membrane-side joining portion is greater, the membrane-side joining portion and the resin frame member can be firmly joined by an anchoring effect of the adhesive.

[0152] (Embodiment 6) In the differential pressure type electrolytic device according to Embodiment 5, the electrolyte membrane can have a first surface (201, 205) facing the first electrode and a second surface (202, 206) facing the second electrode, the membrane-side joining portion can have a first joining portion (203, 207) formed on the first surface and a second joining portion (204, 208) formed on the second surface, and a surface roughness of the second joining portion can be greater than a surface roughness of the first joining portion.

[0153] The adhesive can exert a significant anchoring effect on the second surface facing the second electrode that generates high pressure gas. Thus, the second surface can be firmly joined to the resin frame member.

[0154] (Note 7) In the differential pressure type electrolytic device according to any one of Notes 1 to 6, the electrolyte membrane can have a first ion exchange membrane (41a) in contact with the first electrode, a second ion exchange membrane (41b) in contact with the second electrode, and a support membrane (41c) interposed between the first ion exchange membrane and the second ion exchange membrane and having a tensile strength greater than those of the first ion exchange membrane and the second ion exchange membrane, and the resin frame member can be joined to a peripheral portion (42C) of the support membrane.

[0155] Since the support membrane has a large tensile strength, deformation of the electrolyte membrane can be further suppressed. In addition, the support membrane is less likely to be affected by moisture than the electrolyte membrane. In other words, even in the case of contact with moisture, the support membrane is less likely to swell than the electrolyte membrane. Thus, the joint of the electrolyte membrane to the resin frame member by the adhesive can be suppressed from becoming brittle. That is, the concern that the electrolyte membrane is peeled off from the resin frame member can be eliminated.

[0156] (Note 8) In the differential pressure type electrolytic device according to Note 7, the material of the support membrane can be expanded polytetrafluoroethylene having the same functional group as the functional group involved in ion exchange in the first ion exchange membrane and the second ion exchange membrane.

[0157] According to this structure, ion conduction between the first electrode and the second electrode via the electrolyte membrane can reliably occur.

[0158] (Note 9) In the differential pressure type electrolytic device according to Note 8, the concentration of the functional group of the second ion exchange membrane can be higher than that of the first ion exchange membrane.

[0159] The second ion exchange membrane contains moisture. In the second ion exchange membrane, when the concentration of the functional group involved in ion exchange is high, a large amount of moisture can be held. Thus, even when the second ion exchange membrane is pressed by a high-pressure gas, the second ion exchange membrane can contain a certain amount of moisture. Thus, ion conduction occurs in the second ion exchange membrane as well.

[0160] Furthermore, the present application is not limited to the above-described content, and various structures can be employed within the scope of the gist of the present application.

Claims

1. A pressure differential electrolysis device comprising an electrolysis cell having a membrane electrode structure and a first separator and a second separator, wherein: The membrane electrode structure has an electrolyte membrane sandwiched between a first electrode and a second electrode; the first separator and the second separator sandwich the membrane electrode structure between each other, and a gas having a pressure higher than that of the gas obtained at the first electrode is obtained at the second electrode. The differential pressure electrolysis device is characterized in that: It includes a resin frame component, a first component, a second component and a positioning component, wherein: The resin frame member is joined to a peripheral edge portion of the electrolyte membrane; The first member is interposed between the first separator and the resin frame member in a stacking direction of the first electrode, the electrolyte membrane, and the second electrode; The second member is interposed between the resin frame member and the second spacer in the stacking direction; The positioning member positions the resin frame member relative to the first member or the second member in a plane direction perpendicular to the stacking direction. The positioning member allows the resin frame member to move in the surface direction.

2. The pressure differential electrolysis device according to claim 1, characterized in that: The resin frame member has an insertion hole through which the positioning member is inserted, and a cross-sectional area of ​​the insertion hole in the plane direction is larger than a cross-sectional area of ​​the positioning member in the plane direction.

3. The pressure differential electrolysis device according to claim 1, characterized in that: The electrolyte membrane has a first surface facing the first electrode and a second surface facing the second electrode. The resin frame member is joined to only one of the first surface or the second surface.

4. The pressure differential electrolysis device according to any one of claims 1 to 3, characterized in that: comprising a sealing member and an adhesive, wherein The sealing member surrounds the outer periphery of the second electrode and is interposed between the resin frame member and the second separator in the stacking direction; The adhesive bonds the peripheral edge portion of the electrolyte membrane to the resin frame member. A joining portion between the resin frame member and the electrolyte membrane, which are joined by the adhesive, is located outside an outer peripheral end portion of the sealing member.

5. The pressure differential electrolysis device according to claim 1, characterized in that: including an adhesive for bonding the peripheral edge portion of the electrolyte membrane to the resin frame member, The electrolyte membrane has a membrane-side bonding portion bonded to the resin frame member via the adhesive. In the electrolyte membrane, the membrane-side joining portion has a larger surface roughness than portions other than the membrane-side joining portion.

6. The pressure differential electrolysis device according to claim 5, characterized in that: The electrolyte membrane has a first surface facing the first electrode and a second surface facing the second electrode. The film-side bonding portion includes a first bonding portion formed on the first surface and a second bonding portion formed on the second surface. The second joining portion has a surface roughness greater than that of the first joining portion.

7. The pressure differential electrolysis device according to any one of claims 1 to 3, characterized in that: The electrolyte membrane includes a first ion exchange membrane, a second ion exchange membrane, and a support membrane, wherein: The first ion exchange membrane is in contact with the first electrode; The second ion exchange membrane is in contact with the second electrode; The supporting membrane is interposed between the first ion exchange membrane and the second ion exchange membrane, and has a greater tensile strength than the first ion exchange membrane and the second ion exchange membrane. The resin frame member is bonded to the peripheral edge portion of the supporting film.

8. The pressure differential electrolysis device according to claim 7, characterized in that: The material of the supporting membrane is expanded polytetrafluoroethylene, and the expanded polytetrafluoroethylene has the same functional groups as those participating in ion exchange in the first ion exchange membrane and the second ion exchange membrane.

9. The pressure differential electrolysis device according to claim 8, characterized in that: The second ion exchange membrane has a higher concentration of the functional groups than the first ion exchange membrane.

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