JP7102599B1 - Water electrolysis device - Google Patents

Abstract

A water electrolysis device capable of suppressing manufacturing costs is provided. A water electrolysis device (10) includes an electrolyte membrane (21) having an anode catalyst layer (24) laminated on one surface and a cathode catalyst layer (34) laminated on the other surface, and recesses having an average opening width of 10 μm or more and 250 μm or less. Alternatively, a concavo-convex pattern in which protruding portions with an average distance between apexes of 10 μm or more and 250 μm or less are arranged at an average pitch of 20 μm or more and 500 μm or less is integrally formed on the surface, and the protruding portions of the concavo-convex pattern are arranged in contact with the anode catalyst layer 24, and the anode and a conductive separator member 26 forming a gas diffusion path 27</b>C between itself and the catalyst layer 24 . [Selection drawing] Fig. 1

Description

The present invention relates to a water electrolysis device.

In recent years, water electrolysis devices that generate hydrogen have been attracting attention as a means of utilizing clean energy. Hydrogen is generated and stored in a water electrolysis device using electricity obtained from renewable energy, and if necessary, hydrogen is used to generate electricity in a fuel cell, so that electricity can be continuously generated even with unstable renewable energy. Can be supplied.

Regarding such a water electrolysis device, the configuration of a cell stack has also been developed, and various techniques have been proposed for a cell structure including an electrolyte membrane, an anode, a cathode, and a separator. (See, for example, Patent Document 1).

WO2021 / 111775

In such a water electrolysis device, particularly strong oxidation conditions are generated on the anode side, so that the constituent materials are limited and the cost tends to be high.

The present invention has been made in consideration of the above facts, and an object of the present invention is to provide a water electrolysis device capable of suppressing manufacturing costs.

The water electrolysis device according to the first aspect has an electrolyte membrane in which an anode catalyst layer is laminated on one surface of the electrolyte layer and a cathode catalyst layer is laminated on the other surface, and a groove-shaped recess having an average opening width of 10 μm or more and 250 μm or less. An uneven pattern arranged with an average pitch of 20 μm or more and 500 μm or less is integrally formed on the surface, and a convex portion formed between the adjacent concave portions of the concave- convex pattern is contact-arranged with the anode catalyst layer, and the anode catalyst layer is arranged. It is provided with a conductive separator member that forms a gas diffusion path between the two.
The water electrolysis device according to the second aspect has an electrolyte membrane in which an anode catalyst layer is laminated on one surface of the electrolyte layer and a cathode catalyst layer is laminated on the other surface, and a convex shape in which the average distance between the tops is 10 μm or more and 250 μm or less. A concavo-convex pattern in which the portions are arranged at an average pitch of 20 μm or more and 500 μm or less is integrally formed on the surface, and the concavo-convex portion of the concavo-convex pattern is arranged in contact with the anode catalyst layer, and a gas diffusion path is provided between the portions and the anode catalyst layer. It includes a conductive separator member that constitutes the structure.

In the water electrolysis device according to the first and second aspects, a concavo-convex pattern is integrally formed on the surface of the conductive separator member, and the convex portion of the concavo-convex pattern is arranged in contact with the anode catalyst layer to form a contact with the anode catalyst layer. A gas diffusion path is constructed between them. In the uneven pattern, concave portions having an average opening width of 10 μm or more and 250 μm or less or convex portions having an average distance between tops of 10 μm or more and 250 μm or less are arranged with an average pitch of 20 μm or more and 500 μm or less. Can be diffused.

As described above, by integrally forming the uneven pattern on the surface of the separator member to perform gas diffusion, it is not necessary to provide a separate member for gas diffusion, and the cost can be reduced.

In the water electrolysis device according to the third aspect, the average pitch of the uneven pattern is smaller than the thickness of the separator member.

In the water electrolysis device according to the third aspect, by making the average pitch of the uneven pattern smaller than the thickness of the separator member, it is possible to maintain the ease of production while ensuring the gas diffusibility.

The water electrolysis device according to the fourth aspect is adjacent to an electrolyte film in which an anode catalyst layer is laminated on one side surface of the electrolyte layer and a cathode catalyst layer is laminated on the other surface, and a groove-shaped recess which is uneven in the thickness direction. An uneven pattern in which a convex portion formed between the matching concave portions is formed is integrally formed, and the convex portion of the concave-convex pattern is arranged in contact with the anode catalyst layer, and a gas diffusion path is provided between the convex portion and the anode catalyst layer. The conductive separator member comprises the above, wherein the average pitch of the uneven pattern is smaller than the thickness of the separator member.
In the water electrolysis device according to the fifth aspect, an anode catalyst layer is laminated on one side surface of the electrolyte layer, and an electrolyte film on which a cathode catalyst layer is laminated on the other surface and convex portions that are convex in the thickness direction and are separated from each other are formed. A concave-convex pattern in which a concave portion is formed between the adjacent convex portions is integrally formed, the convex portion of the concave-convex pattern is arranged in contact with the anode catalyst layer, and a gas diffusion path is provided between the convex portion and the anode catalyst layer. The conductive separator member comprises the above, wherein the average pitch of the uneven pattern is smaller than the thickness of the separator member.

In the water electrolysis device according to the fourth and fifth aspects, a concavo-convex pattern is integrally formed on the surface of the conductive separator member, and the convex portion of the concavo-convex pattern is arranged in contact with the anode catalyst layer to form a contact with the anode catalyst layer. A gas diffusion path is constructed between them.

As described above, by integrally forming the uneven pattern on the surface of the separator member to form the gas diffusion path, it is not necessary to provide a separate member for gas diffusion, and the cost can be reduced. Further, since the average pitch of the uneven pattern is set to be smaller than the thickness of the separator member, it is possible to maintain the ease of manufacturing while ensuring the gas diffusibility in the gas diffusion path.

In the water electrolysis device according to the sixth aspect, the contact rate with the electrolyte membrane per unit area in the uneven pattern is 40% or more and 85% or less.

According to the water electrolysis device according to the sixth aspect, good conductivity can be ensured and gas diffusibility can be maintained between the separator member and the anode catalyst layer.

In the water electrolysis device according to the seventh aspect, the convex portion has a circular shape.

By forming the convex portion of the concave-convex pattern into a circular shape, a gas diffusion path can be formed between the convex portion and the anode catalyst layer.

In the water electrolysis device according to the first aspect, the recess is groove-shaped.

By forming the concave portion of the concave-convex pattern into a groove shape, a gas diffusion path can be formed between the concave portion and the anode catalyst layer.

In the water electrolysis device according to the eighth aspect, the separator member is formed with a mainstream portion having a flow path resistance smaller than that of the uneven pattern from the upstream side to the downstream side of the gas diffusion path.

In the water electrolysis device according to the eighth aspect, a mainstream portion having a flow path resistance smaller than that of the uneven pattern is formed on the separator member. Since the mainstream portion is directed from the upstream side to the downstream side of the gas diffusion path, the flow of water and oxygen can be improved by the inflow of water and oxygen from the gas diffusion path to the mainstream portion.

In the water electrolysis device according to the ninth aspect, the separator member is made of titanium.

In the water electrolysis device according to the ninth aspect, the oxidation resistance can be improved by making the separator member made of titanium.

According to the water electrolysis device according to the present invention, the manufacturing cost can be suppressed.

It is a figure which shows the schematic cross-sectional structure of the water electrolysis apparatus which concerns on 1st Embodiment. (A) is a plan view of the anode side separator member of the water electrolyzer according to the first embodiment, and (B) is a sectional view taken along line 2-2 of (A). (A) is a plan view of the cathode side separator member of the water electrolyzer according to the first embodiment, and (B) is a sectional view taken along line 3-3 of (A). (A) is a plan view of the anode side separator member of the water electrolyzer according to the modified example of the first embodiment, and (B) is a sectional view taken along line 4-4 of (A). (A) is a plan view of the anode side separator member of the water electrolyzer according to the second embodiment, and (B) is a cross-sectional view of line 5-5 of (A). (A) is a plan view of the cathode side separator member of the water electrolyzer according to the second embodiment, and (B) is a cross-sectional view of line 6-6 of (A). It is a figure which shows the example (A) (B) (C) of the gas diffusion part of the water electrolysis apparatus which concerns on other embodiment. It is a figure which shows the schematic cross-sectional structure of the water electrolysis apparatus which concerns on other embodiment.

<First Embodiment>
The first embodiment of the water electrolysis device of the present invention will be described with reference to the drawings. In this embodiment, a solid polymer electrolyte membrane type (PEM) water electrolyzer 10 will be described as an example. FIG. 1 shows a schematic cross section of the cell 20 of the water electrolyzer 10.

The cell 20 includes an electrolyte membrane 21. The electrolyte membrane 21 is formed by laminating the anode catalyst layer 24 on one surface of the electrolyte layer 22 and laminating the cathode catalyst layer 34 on the other surface. The separator member 26 is laminated on the anode catalyst layer 24 of the electrolyte membrane 21, and the separator member 36 is laminated on the cathode catalyst layer 34.

The electrolyte layer 22 has a rectangular shape, and a carbon-fluorine-based polymer film, a carbon-fluorine-based polymer film, or the like can be used. The anode catalyst layer 24 covers the inner peripheral side narrower than the outer circumference of one surface of the electrolyte membrane 21, and an Ir-based catalyst or the like can be used. The cathode catalyst layer 34 covers the inner peripheral side narrower than the outer circumference of the other surface of the electrolyte membrane 21, and a Pt / carbon-based catalyst or the like can be used.

A frame-shaped anode seal layer 25 is laminated on the anode catalyst layer 24 side of the electrolyte membrane 21. As shown in FIG. 1, the anode seal layer 25 is formed on the outer periphery of the anode catalyst layer 24 of the electrolyte layer 22. An anode opening 25A is formed in the frame of the anode seal layer 25, and the anode catalyst layer 24 and the gas diffusion portion 27 of the separator member 26 described later are arranged in the anode opening 25A. The anode seal layer 25 is in close contact with the electrolyte layer 22 and the separator member 26, and seals between the two. The anode seal layer 25 can be formed of a resin or rubber material.

A separator member 26 is laminated on the anode seal layer 25. The separator member 26 has a rectangular plate shape, and a gas diffusion portion 27 is integrally formed on the surface of the anode catalyst layer 24 side.

The gas diffusion portion 27 is formed at a position corresponding to the anode catalyst layer 24 in a plan view, has the same shape as the anode catalyst layer 24 in a plan view, and the wall portion 28 is formed in a square shape in a plan view. There is. As shown in FIG. 2A, the gas diffusion portion 27 is formed with a circular convex portion 27B on the entire surface in a plan view. As shown in FIG. 2B, the convex portion 27B has a top portion 27AP arranged flush with the surface of the separator member 26 (based on the thickness surface of the portion where the uneven pattern is not formed). A concave portion 27A recessed from the surface of the separator member 26 is formed between adjacent convex portions 27B (a portion where the convex portion 27B is not formed). In the gas diffusion unit 27, the uneven pattern is integrally formed on the surface in this way. "Integral formation" here means that it is composed of one member instead of another member.

The convex portion 27B is formed so as to be separated from the adjacent convex portion 27B, and the top portion 27AP of the convex portion 27B is flat. By flattening the top 27AP in this way, the contact area with the anode catalyst layer 24 can be increased. The average distance D1 between adjacent convex portions 27B is set to 10 μm or more and 250 μm or less. Further, the average opening width D2 of the recess 27A in a plan view (same as D1 in this embodiment) is 10 μm or more and 250 μm or less. The average pitch P1 of the uneven pattern formed by the convex portion 27B and the concave portion 27A is 20 μm or more and 500 μm or less.

When the average interval D1 and the average opening width D2 are less than 10 μm and the average pitch P1 is less than 20 μm, manufacturing becomes difficult. When the average interval D1 and the average opening diameter D2 exceed 250 μm and the average pitch P1 exceeds 500 μm, the diffusion of gas becomes insufficient and the performance deteriorates.

The average interval D1 and the average opening width D2 are preferably 10 μm or more and 150 μm or less.

Further, the depth B1 of the recess 27A is set to be shallower than the thickness T1 of the separator member 26, and the average pitch P1 of the uneven pattern is set to be smaller than the thickness T1.

The convex portion 27B is arranged in contact with the anode catalyst layer 24 of the electrolyte membrane 21. The convex portion 27B maintains contact with the anode catalyst layer 24 for ensuring conductivity, but the concave portion 27A is arranged so as to surround each convex portion 27B, and the fluid in the concave portion 27A. It is possible to move.

The contact rate of the gas diffusing portion 27 with the anode catalyst layer 24 per unit area is preferably 40% or more and 85% or less in consideration of ensuring conductivity and maintaining gas diffusing property.

The average interval D1, the average aperture width D2, the average pitch P1 of the uneven pattern, and the depth B1 can be measured by a scanning electron microscope, an optical microscope, an image acquired through these, or the like.

A gas diffusion path 27C is formed between the inner anode catalyst layer 24 surrounded by the anode seal layer 25 and the recess 27A of the gas diffusion portion 27. Water is supplied to the gas diffusion path 27C from a water flow path (not shown) provided at one end of the gas diffusion path 27C, and oxygen is supplied from an oxygen flow path (not shown) provided at the other end of the gas diffusion path 27C. Be sent out.

As the separator member 26, titanium, stainless steel, or carbon can be used. In particular, when used as a cell of a water electrolyzer as in the present embodiment, oxygen is generated on the anode side, so it is preferable to use titanium, which is a material having high oxidation resistance, in order to suppress oxidation.

As a method of forming an uneven pattern on the surface of the separator member 26, press working, embossing, sharpening, cutting and the like can be used. The sharpening process refers to a processing method in which the surface is scraped off by applying a blade in an oblique direction to the surface of the plate material, similar to the processing method used when forming the uneven shape of the grater.

A frame-shaped cathode seal layer 35 is laminated on the cathode catalyst layer 34 side of the electrolyte membrane 21. As shown in FIG. 1, the cathode seal layer 35 is formed on the outside of the cathode catalyst layer 34 of the electrolyte layer 22. A cathode opening 35A is formed in the frame of the cathode seal layer 35, and the cathode catalyst layer 34 and the gas diffusion portion 37 of the separator member 36 described later are arranged in the cathode opening 35A. The cathode seal layer 35 is in close contact with the electrolyte layer 22 and the separator member 36, and seals between the two. The cathode seal layer 35 can be formed of a resin or rubber material.

A separator member 36 is laminated on the cathode seal layer 35. The separator member 36 has a rectangular plate shape, and a gas diffusion portion 37 is integrally formed on the surface of the cathode catalyst layer 34 side.

The gas diffusion portion 37 is formed at a position corresponding to the cathode catalyst layer 34 in a plan view, has the same shape as the cathode catalyst layer 34 in a plan view, and the wall portion 28 is formed in a square shape in a plan view. There is. ing. As shown in FIG. 3A, the gas diffusion portion 37 has a circular convex portion 37B formed on the entire surface in a plan view. As shown in FIG. 3B, the convex portion 37B has a top portion 37AP arranged flush with the surface of the separator member 36. A concave portion 37A is formed between adjacent convex portions 37B (a portion where the convex portion 37B is not formed). In the gas diffusion portion 37, the uneven pattern is integrally formed on the surface in this way.

The convex portion 37B is formed so as to be separated from the adjacent convex portion 37B, and the top portion 37AP of the convex portion 37B is flat. By flattening the top 37AP in this way, the contact area with the cathode catalyst layer 34 can be increased. The average distance D3 between adjacent recesses 37A is 10 μm or more and 250 μm or less. Further, the average opening width D4 of the recess 37A in a plan view (same as D3 in this embodiment) is 10 μm or more and 250 μm or less. The average pitch P2 of the uneven pattern formed by the convex portion 37B and the concave portion 37A is 20 μm or more and 500 μm or less.

When the average interval D3, the average opening width D4 is less than 10 μm, and the average pitch P2 is less than 20 μm, manufacturing becomes difficult. When the average interval D3, the average opening width D4 exceeds 250 μm, and the average pitch P2 exceeds 500 μm, the diffusion of gas becomes insufficient and the performance deteriorates.

The average interval D3 and the average opening width D4 are preferably 10 μm or more and 150 μm or less.

The average interval D3, the average opening width D4, the average pitch P2 of the uneven pattern, and the depth B2 can be measured by a scanning electron microscope, an optical microscope, an image acquired through these, or the like.

Further, the depth B2 of the recess 37A is set to be shallower than the thickness T2 of the separator member 36, and the average pitch P2 of the uneven pattern is set to be smaller than the thickness T2.

The convex portion 37B is arranged in contact with the cathode catalyst layer 34 of the electrolyte membrane 21. The convex portion 37B maintains contact with the cathode catalyst layer 34 for ensuring conductivity, but the concave portion 37A is arranged so as to surround each convex portion 37B, and the fluid in the concave portion 37A. It is possible to move.

The contact rate of the gas diffusing portion 37 with the cathode catalyst layer 34 per unit area is preferably 40% or more and 85% or less in consideration of ensuring conductivity and maintaining gas diffusing property.

A gas diffusion path 37C is formed between the inner cathode catalyst layer 34 surrounded by the cathode seal layer 35 and the recess 37A of the gas diffusion portion 37. Hydrogen is sent to the gas diffusion path 37C from a hydrogen flow path (not shown) provided at the other end of the gas diffusion path 37C (the other end of the gas diffusion path 27C separated from the one end provided with the water flow path). Will be done.

As the separator member 36, titanium, stainless steel, carbon or the like can be used.

As a method of forming an uneven pattern on the surface of the separator member 26, press working, embossing, sharpening, cutting and the like can be used.

The water electrolyzer 10 includes a voltage applying means (not shown). A voltage is applied between the separator member 26 and the separator member 36 by the voltage applying means. The voltage and current of the separator member 26 and the separator member 36 are measured by a voltmeter and an ammeter (not shown), and are controlled by a control unit (not shown) based on the voltage and current values between the separator member 26 and the separator member 36. Will be done.

Next, the action and effect of the water electrolyzer 10 of the present embodiment will be described.

When water is supplied from a water flow path (not shown) to one end of the gas diffusion path 27C, the following reaction (1) occurs on the surface of the anode catalyst layer 24 due to the application of a voltage between the separator member 26 and the separator member 36. ..
H ₂ O → 2H ⁺ + 0.5O ₂ + ^2e- (1)

Oxygen O ₂ is diffused by the gas diffusing portion 27 having an uneven pattern, flows toward the other end of the gas diffusing path 27C, and is sent out from the oxygen flow path together with unreacted water (H ₂ O).

The hydrogen ion H ⁺ moves to the cathode side through the electrolyte membrane 21 and obtains an electron e ⁻ supplied by an external wiring (reaction (2)) to become hydrogen H ₂ , which is diffused by the gas diffusing unit 37 and gas. It is delivered from a hydrogen flow path provided at the other end of the diffusion path 37C.
2H ⁺ + ^2e- → H ₂ (2)

In the present embodiment, water, oxygen, and hydrogen in the gas diffusion paths 27C and 37C can be diffused by the gas diffusion portions 27 and 37 having an uneven pattern integrally formed on the separator members 26 and 37. Therefore, it is not necessary to provide a separate member for gas diffusion, and costs such as material cost and processing cost can be reduced. In particular, as compared with a cell in which the gas diffusion layer and the separator member are made of separate members, it is not necessary to plate the separator member, and the manufacturing cost can be reduced.
Further, the interface portion between the gas diffusion layer and the separator member is eliminated, and it is possible to prevent a decrease in electrical connection due to oxidation of the interface portion. Furthermore, it can be continuously manufactured by using manufacturing methods such as press working, embossing, and sharpening, and its size is larger than that when a fiber sintered body or a powder sintered body is used as a gas diffusion layer. The degree of freedom can be increased and the productivity can be improved.

Further, in the present embodiment, the depths B1 and B2 of the recesses 27B and 37B are shallower than the thicknesses T1 and T2 of the separator members 26 and 36, and the average pitch P1 and P2 of the uneven pattern are smaller than the thicknesses T1 and T2. Since it is set, it is possible to maintain the ease of manufacturing the gas diffusion portions 27 and 37 while ensuring the gas diffusibility in the gas diffusion paths 27C and 37C.

The gas diffusion portion 27 of the separator member 26 may be provided with a mainstream portion 29 as shown in FIGS. 4A and 4B. The mainstream portion 29 is a groove extending from the upstream side (one end side where water from the water flow path flows in) to the downstream side (the other end side where the oxygen flow path where oxygen and water flow out is formed) of the gas diffusion path 27C. The groove width is larger than the diameter of the recess 27B. As an example, in FIG. 4A, the upper side of the figure is upstream and the lower side is downstream. Therefore, the flow path resistance of the mainstream portion 29 is smaller than that of the concave-convex pattern portion in which only the recess 27B is formed. By forming the mainstream portion 29, water and oxygen can flow from the gas diffusion path 27C into the mainstream portion 29, so that the flow of water and oxygen can be improved.

The mainstream portion 29 may also be formed on the separator member 36 on the cathode side.

<Second Embodiment>
Next, a second embodiment of the present invention will be described with reference to FIGS. 5 and 6. In the present embodiment, the same parts as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

In the water electrolyzer 10 of the present embodiment, separator members 26-2 and 36-2 are used instead of the separator members 26 and 36. The configurations other than the separator members 26 and 36 are the same as those in the first embodiment.

Separator members 26-2 are laminated on the anode seal layer 25. The separator member 26-2 has a rectangular plate shape, and a gas diffusion portion 27-2 is integrally formed on the surface of the anode catalyst layer 24 side.

The gas diffusion portion 27-2 is formed at a position corresponding to the anode catalyst layer 24 in a plan view, and has the same shape as the anode catalyst layer 24 in a plan view. As shown in FIG. 5A, the gas diffusion portion 27-2 has a groove recess 27B-2 formed by a plurality of grooves extending from one end side to the other end side in a plan view, and a groove recess 27B. A convex portion 27A-2 formed between -2 is formed. As shown in FIG. 5B, the groove recess 27B-2 has a concave shape recessed from the surface of the separator member 26-2. In the portion where the groove recess 27B-2 is not formed, a long convex portion 27A-2 sandwiched between the adjacent groove recesses 27B-2 is formed. In the gas diffusion portion 27-2, the uneven pattern is integrally formed on the surface in this way.

The groove recess 27B-2 is formed so as to be separated from the adjacent groove recess 27B-2, and the top 27AP-2 of the convex portion 27A-2 is flat. By flattening the top 27AP-2 in this way, the contact area with the anode catalyst layer 24 can be increased. The average distance D5 between adjacent convex portions 27A-2 is 10 μm or more and 250 μm or less. Further, the average opening width D6 (same as D5 in this embodiment) in a plan view is set to 10 μm or more and 250 μm or less. The average pitch P3 of the uneven pattern formed by the convex portion 27A-2 and the groove concave portion 27B-2 is 20 μm or more and 500 μm or less.

When the average interval D5, the average opening width D6 is less than 10 μm, and the average pitch P3 is less than 20 μm, manufacturing becomes difficult. When the average interval D5, the average opening width D6 exceeds 250 μm, and the average pitch P3 exceeds 500 μm, the diffusion of gas becomes insufficient and the performance deteriorates.

The average interval D5 and the average opening width D6 are preferably 10 μm or more and 150 μm or less.

Further, the depth B1 of the groove recess 27B-2 is set to be shallower than the thickness T1 of the separator member 26-2, and the average pitch P3 of the uneven pattern is set to be smaller than the thickness T1.

The convex portion 27A-2 is arranged in contact with the anode catalyst layer 24 of the electrolyte membrane 21. The convex portion 27A-2 maintains contact with the anode catalyst layer 24 for ensuring conductivity, but has a gap sufficient for fluid movement between the respective groove concave portions 27B-2. ing.

The contact rate of the gas diffusing portion 27-2 with the anode catalyst layer 24 per unit area is preferably 40% or more and 85% or less in consideration of ensuring conductivity and maintaining gas diffusing property.

The average interval D5, the average opening width D6, the average pitch P3 of the uneven pattern, and the depth B1 can be measured by a scanning electron microscope, an optical microscope, an image acquired through these, or the like.

A gas diffusion path 27C is formed between the inner anode catalyst layer 24 surrounded by the anode seal layer 25 and the groove recess 27B-2 of the gas diffusion portion 27-2.

As the separator member 26-2, the same member as the separator member 26 can be used. As a method for forming an uneven pattern on the surface of the separator member 26-2, press working, embossing, sharpening, cutting and the like are performed. Can be used.

A separator member 36-2 is laminated on the cathode seal layer 35. The separator member 36-2 has a rectangular plate shape, and a gas diffusion portion 37-2 is integrally formed on the surface of the cathode catalyst layer 34 side.

The gas diffusion portion 37-2 is formed at a position corresponding to the cathode catalyst layer 34 in a plan view, and has the same shape as the cathode catalyst layer 34 in a plan view. As shown in FIG. 6A, the gas diffusion portion 37-2 has a groove recess 37B-2 formed by a plurality of grooves extending from one end side to the other end side in a plan view, and a groove recess 37B. A convex portion 37A-2 formed between -2 is formed. As shown in FIG. 6B, the groove recess 37B-2 has a concave shape recessed from the surface of the separator member 36-2. In the portion where the groove recess 37B-2 is not formed, a long convex portion 37A-2 is formed by being sandwiched between the adjacent groove recesses 37B-2. In the gas diffusion portion 37-2, the uneven pattern is integrally formed on the surface in this way.

The groove recess 37B-2 is formed so as to be separated from the adjacent groove recess 37B-2, and the top 37AP-2 of the convex portion 37A-2 is flat. By flattening the top 37AP-2 in this way, the contact area with the cathode catalyst layer 34 can be increased. The average distance D7 between adjacent convex portions 37A-2 is 10 μm or more and 250 μm or less. Further, the average opening width D8 (same as D7 in this embodiment) in a plan view is set to 10 μm or more and 250 μm or less. The average pitch P4 of the uneven pattern formed by the convex portion 37A-2 and the groove concave portion 37B-2 is set to 20 μm or more and 500 μm or less.

When the average interval D7, the average opening width D8 is less than 10 μm, and the average pitch P4 is less than 20 μm, manufacturing becomes difficult. When the average interval D7, the average opening width D8 exceeds 250 μm, and the average pitch P4 exceeds 500 μm, the diffusion of gas becomes insufficient and the performance deteriorates.

The average interval D7 and the average opening width D8 are preferably 10 μm or more and 150 μm or less.

Further, the depth B1 of the groove recess 37B-2 is set to be shallower than the thickness T1 of the separator member 36-2, and the average pitch P4 of the uneven pattern is set to be smaller than the thickness T1.

The convex portion 37A-2 is arranged in contact with the cathode catalyst layer 34 of the electrolyte membrane 21. The convex portion 37A-2 maintains contact with the cathode catalyst layer 34 for ensuring conductivity, but has a gap sufficient for fluid movement between the respective groove concave portions 37B-2. ing.

The contact rate of the gas diffusing portion 37-2 with the cathode catalyst layer 34 per unit area is preferably 40% or more and 85% or less in consideration of ensuring conductivity and maintaining gas diffusing property.

The average interval D7, the average opening width D8, the average pitch P4 of the uneven pattern, and the depth B1 can be measured by a scanning electron microscope, an optical microscope, an image acquired through these, or the like.

A gas diffusion path 37C is formed between the inner cathode catalyst layer 34 surrounded by the cathode seal layer 35 and the groove recess 37B-2 of the gas diffusion portion 37-2.

As the separator member 36-2, the same member as the separator member 36 can be used. As a method for forming an uneven pattern on the surface of the separator member 36-2, press working, embossing, sharpening, cutting and the like are performed. Can be used.

<Other Embodiments>
In the first embodiment, as the concave-convex pattern for forming the gas diffusion portion 27 in the separator members 26 and 36, a circular convex portion in a plan view has been described as an example, but a convex portion having another shape may be used. For example, as shown in FIG. 7C, an concave-convex pattern in which the oval 45 is a convex portion and the concave portion 46 is formed in a portion where the oval 45 is not formed may be used.

Further, the convex portions may be randomly arranged without being aligned. Further, the size and shape of the convex portion do not have to be the same, and may be a random shape.

Further, in the second embodiment, as an uneven pattern for forming the gas diffusion portion 27-2 in the separator members 26-2 and 36-2, a plurality of long linear grooves in a plan view will be described as an example. However, a groove having another shape may be used. For example, as shown in FIG. 7A, a concavo-convex pattern in which a plurality of wavy grooves 41 are recessed and a convex portion 42 is formed in an adjacent groove-to-groove portion may be used. Further, a long linear groove 43 arranged diagonally in a plan view may be used as a concave portion, and a convex portion 44 of a portion surrounded by the groove 43 may be used.

Further, in the present embodiment, the gas diffusion portions 27 and 37 are formed on one side of the separator members 26 and 36, but as shown in FIG. 8, they can be formed on both sides to form a cell stack. In this case, one surface side of one separator member 26 arranged in the middle portion of the lamination becomes the gas diffusion portion 27 facing the anode catalyst layer 24, and the other surface side becomes the gas diffusion portion 37 facing the cathode catalyst layer 34. Become.

Further, in each of the above-described embodiments, the solid polymer electrolyte membrane type (PEM) water electrolyzer 10 has been described as an example, but the present invention can also be used for an anion exchange membrane type (AEM) water electrolyzer. ..

10 Water electrolyzer (water electrolyzer)
21 Electrolyte film 22 Electrolyte layer 24 Anode catalyst layer 26, 26-2 Separator member 27 Gas diffusion part 27A Convex part 27AP Top part 27B Recessed part 27B-2 Groove concave part (recessed part)
27C Gas diffusion path 29 Mainstream 34 Cathode catalyst layers 41, 43 Grooves (recesses)
42, 44 Convex 45 Oval (convex)
46 Recesses D1 Average spacing D2 Opening average width D5 Average spacing D6 Opening average width P1, P3 Average pitch

Claims (9)

An electrolyte membrane in which an anode catalyst layer is laminated on one surface of the electrolyte layer and a cathode catalyst layer is laminated on the other surface.
A concave-convex pattern in which groove-shaped concave portions having an average opening width of 10 μm or more and 250 μm or less are arranged at an average pitch of 20 μm or more and 500 μm or less is integrally formed on the surface, and the convex portion formed between the concave portions adjacent to the concave-convex pattern is described. A conductive separator member that is arranged in contact with the anode catalyst layer and forms a gas diffusion path between the anode catalyst layer and the anode catalyst layer.
Equipped with a water electrolysis device. An electrolyte membrane in which an anode catalyst layer is laminated on one surface of the electrolyte layer and a cathode catalyst layer is laminated on the other surface.
A concavo-convex pattern in which convex portions having an average distance between the tops of 10 μm or more and 250 μm or less are arranged at an average pitch of 20 μm or more and 500 μm or less is integrally formed on the surface, and the convex portions of the concavo-convex pattern are arranged in contact with the anode catalyst layer. A conductive separator member forming a gas diffusion path between the anode catalyst layer and the anode catalyst layer.
Equipped with a water electrolysis device. The average pitch of the uneven pattern is smaller than the thickness of the separator member.
The water electrolysis device according to claim 1 or 2 . An electrolyte membrane in which an anode catalyst layer is laminated on one side surface of the electrolyte layer and a cathode catalyst layer is laminated on the other surface.
A groove-shaped recess that becomes uneven in the thickness direction and a concave-convex pattern that forms a convex portion formed between the adjacent concave portions are integrally formed, and the convex portion of the concave-convex pattern is arranged in contact with the anode catalyst layer. A conductive separator member that forms a gas diffusion path between the anode catalyst layer and the anode catalyst layer, wherein the average pitch of the uneven pattern is smaller than the thickness of the separator member.
With,
Water electrolysis device. An electrolyte membrane in which an anode catalyst layer is laminated on one side surface of the electrolyte layer and a cathode catalyst layer is laminated on the other surface.
Convex portions that are convex in the thickness direction and are separated from each other are formed, a concave-convex pattern in which concave portions are formed between the adjacent convex portions is integrally formed, and the convex portions of the concave-convex pattern are arranged in contact with the anode catalyst layer. A conductive separator member that forms a gas diffusion path between the anode catalyst layer and the anode catalyst layer, wherein the average pitch of the uneven pattern is smaller than the thickness of the separator member.
With,
Water electrolysis device. The convex portion has a circular shape.
The water electrolysis device according to claim 2 or 5 . The contact rate with the electrolyte membrane per unit area in the uneven pattern is 40% or more and 85% or less.
The water electrolysis device according to any one of claims 1 to 6 . The separator member is formed with a mainstream portion having a flow path resistance smaller than that of the uneven pattern from the upstream side to the downstream side of the gas diffusion path.
The water electrolysis device according to any one of claims 1 to 7 . The separator member is made of titanium.
The water electrolysis device according to any one of claims 1 to 7.

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