阅读说明：本技术 电化学式氢泵 (Electrochemical hydrogen pump ) 是由 鹈饲邦弘 中植贵之 可儿幸宗 于 2019-12-16 设计创作，主要内容包括：一种电化学式氢泵,具备：电解质膜、设在电解质膜的一个主面上的阳极催化剂层、设在电解质膜的另一主面上的阴极催化剂层、设在阳极催化剂层上的阳极气体扩散层、设在阳极气体扩散层上的阳极隔膜、以及在阳极催化剂层与阴极催化剂层之间施加电压的电压施加器,通过电压施加器施加上述电压,使供给到阳极催化剂层上的含氢气体中的氢向阴极催化剂层上移动并升压,阳极气体扩散层包含碳多孔体片,碳多孔体片包含碳纤维和不同于碳纤维的碳材料,碳多孔体片中,阳极隔膜侧的第1表面层的气孔率大于阳极催化剂层侧的第2表面层的气孔率。(An electrochemical hydrogen pump is provided with: the present invention relates to a gas-liquid separator including an electrolyte membrane, an anode catalyst layer provided on one principal surface of the electrolyte membrane, a cathode catalyst layer provided on the other principal surface of the electrolyte membrane, an anode gas diffusion layer provided on the anode catalyst layer, an anode separator provided on the anode gas diffusion layer, and a voltage applier applying a voltage between the anode catalyst layer and the cathode catalyst layer, wherein the voltage applier applies the voltage to move hydrogen in a hydrogen-containing gas supplied to the anode catalyst layer to the cathode catalyst layer and raise the pressure of the hydrogen, the anode gas diffusion layer includes a carbon porous sheet including carbon fibers and a carbon material different from the carbon fibers, and the porosity of a 1 st surface layer on the anode separator side is larger than the porosity of a 2 nd surface layer on the anode catalyst layer side.)

1. An electrochemical hydrogen pump is provided with:

an electrolyte membrane,

An anode catalyst layer provided on one main surface of the electrolyte membrane,

A cathode catalyst layer provided on the other main surface of the electrolyte membrane,

An anode gas diffusion layer disposed on the anode catalyst layer,

An anode separator provided on the anode gas diffusion layer, and

a voltage applicator that applies a voltage between the anode catalyst layer and the cathode catalyst layer,

applying a voltage by the voltage applicator to move hydrogen in the hydrogen-containing gas supplied to the anode catalyst layer to the cathode catalyst layer and raise the pressure,

the anode gas diffusion layer comprises a carbon porous sheet containing carbon fibers and a carbon material different from the carbon fibers, and in the carbon porous sheet, the porosity of the 1 st surface layer on the anode separator side is larger than the porosity of the 2 nd surface layer on the anode catalyst layer side.

2. The electrochemical hydrogen pump according to claim 1, wherein the carbon porous body sheet has a carbon density of the 1 st surface layer lower than a carbon density of the 2 nd surface layer.

3. The electrochemical hydrogen pump according to claim 1 or 2, wherein the carbon material of the 1 st surface layer has a density lower than that of the carbon material of the 2 nd surface layer in the carbon porous body sheet.

4. The electrochemical hydrogen pump according to any one of claims 1 to 3, wherein the carbon material in the carbon porous sheet is a carbide of a thermosetting resin.

5. The electrochemical hydrogen pump according to any one of claims 1 to 4, wherein the carbon fibers of the 1 st surface layer have a density lower than that of the carbon fibers of the 2 nd surface layer in the carbon porous sheet.

6. The electrochemical hydrogen pump according to any one of claims 1 to 5, wherein a flow path through which a hydrogen-containing gas flows is provided in the 1 st surface layer of the porous carbon sheet.

7. The electrochemical hydrogen pump of any one of claims 1 to 6, wherein the 2 nd surface layer comprises a hydrophobic layer in the carbon porous sheet.

8. The electrochemical hydrogen pump according to any one of claims 1 to 6, wherein a hydrophobic layer is provided on the 2 nd surface layer in the carbon porous sheet.

9. The electrochemical hydrogen pump of claim 7 or 8, the hydrophobic layer comprising a hydrophobic resin and carbon black.

Technical Field

The present disclosure relates to an electrochemical hydrogen pump.

Background

In recent years, hydrogen has been attracting attention as a clean alternative energy source to replace fossil fuels due to environmental problems such as global warming and energy problems such as depletion of petroleum resources. Hydrogen emits substantially only water even when it is burned, does not emit carbon dioxide which causes global warming, and does not emit substantially nitrogen oxides or the like, and therefore, is expected as clean energy. Further, as a device for efficiently utilizing hydrogen as a fuel, for example, a fuel cell is being developed and popularized for a power source for automobiles and power generation for home use and private use.

In the upcoming hydrogen society, in addition to the production of hydrogen, development of a technology capable of storing hydrogen at a high density and transporting or utilizing hydrogen at a small capacity and low cost is required. In particular, to promote the spread of fuel cells as distributed energy sources, it is necessary to provide a hydrogen supply infrastructure. In addition, various studies have been made to produce, purify, and store high-purity hydrogen at high density in order to stably supply hydrogen.

For example, patent document 1 proposes a high-pressure hydrogen production apparatus in which a laminate of a solid polymer electrolyte membrane, a power supply body, and a separator is clamped by end plates, and the laminate is fastened by fastening bolts inserted through the end plates. In this high-pressure hydrogen production apparatus, when a pressure difference of a predetermined pressure or more is generated between the high-pressure side cathode power supply and the low-pressure side anode power supply, the solid polymer electrolyte membrane and the low-pressure side anode power supply deform. This increases the contact resistance between the cathode power supply on the high voltage side and the solid polymer electrolyte membrane. Therefore, the high-pressure hydrogen production apparatus of patent document 1 is provided with a pressing means such as a coil spring or a coil spring, and presses and adheres the high-pressure side cathode power supply to the solid polymer electrolyte membrane even if the solid polymer electrolyte membrane and the low-pressure side anode power supply are deformed. This can suppress an increase in contact resistance between the high-voltage-side cathode power supply and the solid polymer electrolyte membrane.

For example, patent document 2 discloses an anode power feeder in which a base portion of a power feeder made of a sintered body of titanium powder is subjected to press working, so that the porosity of the surface layer portion of the base portion is lower than the porosity of the base portion. This can improve the compactness and smoothness of the surface layer portion, and thus can reduce damage to the electrolyte membrane.

Disclosure of Invention

An object of an aspect of the present disclosure (aspect) is to provide an electrochemical hydrogen pump, as an example, which can suppress the occurrence of flooding due to water in an anode gas diffusion layer more than ever.

In order to solve the above problem, an electrochemical hydrogen pump according to one aspect of the present disclosure includes: an electrolyte membrane, an anode catalyst layer provided on one principal surface of the electrolyte membrane, a cathode catalyst layer provided on the other principal surface of the electrolyte membrane, an anode gas diffusion layer provided on the anode catalyst layer, an anode separator provided on the anode gas diffusion layer, and a voltage applicator that applies a voltage between the anode catalyst layer and the cathode catalyst layer, applying the voltage by the voltage applicator to move hydrogen in the hydrogen-containing gas supplied onto the anode catalyst layer onto the cathode catalyst layer and raise the pressure, the anode gas diffusion layer comprises a carbon porous sheet comprising carbon fibers and a carbon material different from the carbon fibers, in the carbon porous sheet, the porosity of the 1 st surface layer on the anode separator side is larger than the porosity of the 2 nd surface layer on the anode catalyst layer side.

The electrochemical hydrogen pump according to one embodiment of the present disclosure exhibits the following effect, and can suppress the occurrence of flooding due to water in the anode gas diffusion layer more than ever.

Drawings

Fig. 1A is a diagram showing an example of the electrochemical hydrogen pump according to embodiment 1.

Fig. 1B is an enlarged view of a portion B of the electrochemical hydrogen pump of fig. 1A.

Fig. 2A is a diagram showing an example of the electrochemical hydrogen pump according to embodiment 1.

Fig. 2B is an enlarged view of a portion B of the electrochemical hydrogen pump of fig. 2A.

Fig. 3 is a diagram showing an example of the carbon porous body sheet in the electrochemical hydrogen pump according to embodiment 1.

Fig. 4A is a diagram showing an example of an SEM cross-sectional image of the carbon porous body sheet in the electrochemical hydrogen pump according to embodiment 1.

Fig. 4B is a diagram showing an example of an SEM cross-sectional image of the carbon porous body sheet in the electrochemical hydrogen pump according to embodiment 1.

Fig. 4C is a diagram showing an example of an SEM cross-sectional image of the carbon porous body sheet in the electrochemical hydrogen pump according to embodiment 1.

Fig. 5 is a diagram showing an example of the carbon porous body sheet in the electrochemical hydrogen pump according to embodiment 2.

Fig. 6A is a diagram showing an example of the carbon porous body sheet in the electrochemical hydrogen pump according to embodiment 3.

Fig. 6B is a diagram showing an example of a carbon porous body sheet in the electrochemical hydrogen pump according to the modification of embodiment 3.

Detailed Description

Patent documents 1 and 2 do not discuss the problem of flow path blockage (hereinafter referred to as flooding) caused by water in a power supply body made of a porous material.

Here, for example, when an electric current flows between the anode electrode and the cathode electrode of the electrochemical hydrogen pump, protons move from the anode electrode to the cathode electrode in the electrolyte membrane together with water. At this time, when the operating temperature of the electrochemical hydrogen pump is equal to or higher than a predetermined temperature, water (electro-osmotic water) moving from the anode electrode to the cathode electrode exists as water vapor, and the higher the hydrogen pressure of the cathode electrode is, the more the proportion of the water existing as liquid water increases. In addition, when liquid water is present at the cathode electrode, a part of the water is pushed back to the anode electrode by a pressure difference between the cathode electrode and the anode electrode, and the amount of water pushed back to the anode electrode increases as the hydrogen pressure at the cathode electrode increases. As the hydrogen pressure of the cathode electrode increases, water pushed back to the anode electrode tends to overflow the anode gas diffusion layer of the anode electrode. When the gas diffusibility is impaired in the anode electrode due to such flooding, the diffusion resistance of the electrochemical hydrogen pump increases, and the efficiency of the hydrogen pressure raising operation of the electrochemical hydrogen pump may be reduced.

Therefore, an electrochemical hydrogen pump according to aspect 1 of the present disclosure includes: the present invention relates to a gas-liquid separator including an electrolyte membrane, an anode catalyst layer provided on one principal surface of the electrolyte membrane, a cathode catalyst layer provided on the other principal surface of the electrolyte membrane, an anode gas diffusion layer provided on the anode catalyst layer, an anode separator provided on the anode gas diffusion layer, and a voltage applier applying a voltage between the anode catalyst layer and the cathode catalyst layer, wherein the voltage applier applies the voltage to move hydrogen in a hydrogen-containing gas supplied to the anode catalyst layer to the cathode catalyst layer and raise the pressure of the hydrogen, the anode gas diffusion layer includes a carbon porous sheet including carbon fibers and a carbon material different from the carbon fibers, and the porosity of a 1 st surface layer on the anode separator side is larger than the porosity of a 2 nd surface layer on the anode catalyst layer side.

For example, the electrochemical hydrogen pump according to claim 2 of the present disclosure may be the electrochemical hydrogen pump according to claim 1, wherein the carbon density of the 1 st surface layer is lower than the carbon density of the 2 nd surface layer in the carbon porous body sheet.

With the above configuration, the electrochemical hydrogen pump of the present embodiment can suppress the occurrence of flooding due to water in the anode gas diffusion layer more than ever.

Specifically, by increasing the porosity of the 1 st surface layer on the anode separator side of the carbon porous sheet, for example, the flow of the hydrogen-containing gas in the carbon porous sheet facilitates the discharge of water present in the carbon porous sheet to the outside of the carbon porous sheet. Further, by reducing the porosity of the 2 nd surface layer on the anode catalyst layer side of the carbon porous body sheet, it is possible to suppress the water pushed back to the anode electrode by the pressure difference between the cathode electrode and the anode electrode from passing through the 2 nd surface layer.

As described above, the electrochemical hydrogen pump of the present embodiment can suppress the occurrence of flooding due to water in the anode gas diffusion layer, and as a result, can suitably maintain the gas diffusibility in the anode.

The electrochemical hydrogen pump according to claim 3 of the present disclosure may be the electrochemical hydrogen pump according to claim 1 or 2, wherein the carbon material of the 1 st surface layer has a density lower than that of the carbon material of the 2 nd surface layer in the carbon porous sheet.

With this configuration, in the electrochemical hydrogen pump of the present embodiment, the relationship in the size of the porosity between the 1 st surface layer and the 2 nd surface layer in the carbon porous body sheet can be set appropriately by the difference in the density of the carbon material contained in the carbon porous body sheet.

An electrochemical hydrogen pump according to claim 4 of the present disclosure may be the electrochemical hydrogen pump according to any one of claims 1 to 3, wherein the carbon material in the porous carbon sheet is a carbide of a thermosetting resin.

The thermosetting resin is a resin that is composed of a polymer material that is polymerized by heating and is cured without being restored. In this case, a carbide of a thermosetting resin can be used as the carbon material contained in the carbon porous sheet. For example, if a carbon fiber sheet impregnated with a thermosetting resin is fired, a carbon porous sheet having high rigidity, high electrical conductivity, and high gas diffusion properties, which contains carbon fibers and a carbide of a thermosetting resin, can be obtained.

An electrochemical hydrogen pump according to claim 5 of the present disclosure may be the electrochemical hydrogen pump according to any one of claims 1 to 4, wherein the density of the carbon fibers in the 1 st surface layer is lower than the density of the carbon fibers in the 2 nd surface layer in the carbon porous sheet.

With this configuration, in the electrochemical hydrogen pump of the present embodiment, the relationship in the size of the porosity between the 1 st surface layer and the 2 nd surface layer in the carbon porous sheet can be appropriately set by the difference in the density of the carbon fibers contained in the carbon porous sheet.

An electrochemical hydrogen pump according to claim 6 of the present disclosure may be the electrochemical hydrogen pump according to any one of claims 1 to 5, wherein the porous carbon sheet is provided with a flow path through which the hydrogen-containing gas flows in the 1 st surface layer.

With this configuration, in the electrochemical hydrogen pump of the present embodiment, the flow channel is provided in the 1 st surface layer on the anode separator side of the carbon porous body sheet, and therefore, for example, the hydrogen-containing gas in the carbon porous body sheet flows, whereby water present in the flow channel is easily discharged to the outside of the carbon porous body sheet. Thus, the electrochemical hydrogen pump of the present embodiment can suppress the occurrence of flooding due to water in the anode gas diffusion layer, and as a result, can appropriately maintain the gas diffusibility in the anode.

In the electrochemical hydrogen pump of the present embodiment, the flow path through which the hydrogen-containing gas flows can be easily provided in the 1 st surface layer on the anode separator side of the carbon porous body sheet by, for example, die molding. Therefore, the electrochemical hydrogen pump of the present embodiment is easier to form a flow path than when the flow path through which the hydrogen-containing gas flows is cut in, for example, a metal anode separator.

An electrochemical hydrogen pump according to claim 7 of the present disclosure may be the electrochemical hydrogen pump according to any one of claims 1 to 6, wherein the 2 nd surface layer of the porous carbon sheet includes a hydrophobic layer. An electrochemical hydrogen pump according to claim 8 of the present disclosure may be the electrochemical hydrogen pump according to any one of claims 1 to 6, wherein the hydrophobic layer is provided on the 2 nd surface layer in the porous carbon sheet.

With this configuration, the electrochemical hydrogen pump of the present embodiment can impart water repellency to the porous carbon sheet by the water-repellent layer included in the 2 nd surface layer on the anode catalyst layer side or the water-repellent layer provided on the 2 nd surface layer on the anode catalyst layer side. Accordingly, the water pushed back to the anode electrode by the pressure difference between the cathode electrode and the anode electrode can be quickly discharged to the outside by the flow of the hydrogen-containing gas in the water-repellent layer. Therefore, the electrochemical hydrogen pump of the present embodiment can suppress the occurrence of flooding due to water in the anode gas diffusion layer, and as a result, can appropriately maintain the gas diffusion property in the anode.

The electrochemical hydrogen pump according to claim 9 of the present disclosure may be the electrochemical hydrogen pump according to claim 7 or 8, wherein the water-repellent layer includes a hydrophobic resin and carbon black.

With this configuration, the electrochemical hydrogen pump of the present embodiment can appropriately exhibit the hydrophobicity of the anode gas diffusion layer by including the hydrophobic layer with the hydrophobic resin and the carbon black.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The embodiments described below all show examples of the above-described embodiments. Therefore, the shapes, materials, components, arrangement positions of components, connection forms, and the like shown below are only examples, and the above-described embodiments are not limited as long as they are not described in the claims. Among the following components, those not recited in the independent claims indicating the highest concept of the above-described embodiments will be described as optional components. In the drawings, the same reference numerals are attached to the elements, and the description thereof may be omitted. For easy understanding, the drawings schematically show the respective constituent elements, and the shapes, the size ratios, and the like may not be accurately shown.

(embodiment 1)

[ Structure of the device ]

Fig. 1A and 2A are diagrams showing an example of the electrochemical hydrogen pump according to embodiment 1. Fig. 1B is an enlarged view of a portion B of the electrochemical hydrogen pump of fig. 1A. Fig. 2B is an enlarged view of a portion B of the electrochemical hydrogen pump of fig. 2A.

Fig. 1A shows a vertical cross section of the electrochemical hydrogen pump 100, which includes a straight line passing through the center of the electrochemical hydrogen pump 100 and the center of the cathode gas discharge manifold 50 in a plan view. Fig. 2A shows a vertical cross section of the electrochemical hydrogen pump 100, which includes a straight line passing through the center of the electrochemical hydrogen pump 100, the center of the anode gas introduction manifold 27, and the center of the anode gas discharge manifold 30 in a plan view.

In the example shown in fig. 1A and 2A, the electrochemical hydrogen pump 100 includes at least one hydrogen pump cell 100A.

In the electrochemical hydrogen pump 100, a plurality of hydrogen pump cells 100A are stacked. For example, in fig. 1A and 2A, 3 stages of hydrogen pump units 100A are stacked, but the number of hydrogen pump units 100A is not limited to this. That is, the number of the hydrogen pump cells 100A may be set to an appropriate number based on the operation conditions such as the amount of hydrogen to be boosted by the electrochemical hydrogen pump 100.

The hydrogen pump cell 100A includes AN electrolyte membrane 11, AN anode electrode AN, a cathode electrode CA, a cathode separator 16, AN anode separator 17, and AN insulator 21. Further, in the hydrogen pump unit 100A, an electrolyte membrane 11, an anode catalyst layer 13, a cathode catalyst layer 12, an anode gas diffusion layer 15, a cathode gas diffusion layer 14, an anode separator 17, and a cathode separator 16 are laminated.

The anode electrode AN is provided on one main surface of the electrolyte membrane 1. The anode electrode AN is AN electrode including AN anode catalyst layer 13 and AN anode gas diffusion layer 15. Further, an annular seal member 43 is provided so as to surround the periphery of the anode catalyst layer 13 in plan view, and the anode catalyst layer 13 is appropriately sealed by the seal member 43.

The cathode electrode CA is provided on the other main surface of the electrolyte membrane 11. The cathode electrode CA is an electrode including a cathode catalyst layer 12 and a cathode gas diffusion layer 14. Further, an annular seal member 42 is provided so as to surround the periphery of the cathode catalyst layer 12 in plan view, and the cathode catalyst layer 12 is appropriately sealed by the seal member 42.

As described above, the electrolyte membrane 11 is sandwiched by the anode electrode AN and the cathode electrode CA so as to be in contact with the anode catalyst layer 13 and the cathode catalyst layer 12, respectively. The laminate of the cathode Electrode CA, the electrolyte Membrane 11 and the anode Electrode AN is referred to as a Membrane Electrode Assembly (hereinafter referred to as "MEA").

The electrolyte membrane 11 has proton conductivity. The electrolyte membrane 1 may have various structures as long as it has proton conductivity. Examples of the electrolyte membrane 1 include, but are not limited to, a fluorine-based polymer electrolyte membrane and a hydrocarbon-based electrolyte membrane. Specifically, as the electrolyte membrane 1, for example, Nafion (registered trademark, manufactured by dupont) and Aciplex (registered trademark, manufactured by asahi chemicals co.

The anode catalyst layer 13 is provided on one principal surface of the electrolyte membrane 11. The anode catalyst layer 13 contains, for example, platinum as a catalyst metal, but is not limited thereto.

The cathode catalyst layer 12 is provided on the other main surface of the electrolyte membrane 1. The cathode catalyst layer 12 contains, for example, platinum as a catalyst metal, but is not limited thereto.

Examples of the catalyst carrier for the cathode catalyst layer 12 and the anode catalyst layer 13 include carbon particles such as carbon black and graphite, and conductive oxide particles, but are not limited thereto.

In the cathode catalyst layer 12 and the anode catalyst layer 13, catalyst metal particles are supported on the catalyst carrier in a highly dispersed manner. In addition, in order to increase the electrode reaction sites, a hydrogen ion conductive ionomer component is generally added to the cathode catalyst layer 12 and the anode catalyst layer 13.

A cathode gas diffusion layer 14 is provided on the cathode catalyst layer 12. The cathode gas diffusion layer 14 is made of a porous material and has electrical conductivity and gas diffusion properties. The cathode gas diffusion layer 14 has elasticity so as to appropriately follow displacement and deformation of the member due to the pressure difference between the cathode CA and the anode AN during the hydrogen pressure increasing operation of the electrochemical hydrogen pump 100.

Here, in the electrochemical hydrogen pump 100 of the present embodiment, the cathode gas diffusion layer 14 is housed in the concave portion of the cathode separator 16, and is disposed so as to protrude from the concave portion in the thickness direction thereof, although not shown, before the hydrogen pump unit 100A is fastened by the fastener 25. Therefore, when the hydrogen pump unit 100A is fastened by the fastener 25, the thickness of the cathode gas diffusion layer 14 is compressively deformed by an amount protruding from the concave portion. This is due to the following reason.

During the hydrogen pressure increasing operation of the electrochemical hydrogen pump 100, a high pressure is applied to the anode gas diffusion layer 15, the anode catalyst layer 13, and the electrolyte membrane 11 due to the pressure difference between the cathode CA and the anode AN, whereby the anode gas diffusion layer 15, the anode catalyst layer 13, and the electrolyte membrane 11 are compressed and deformed. However, in the electrochemical hydrogen pump 100 of the present embodiment, with the above configuration, the cathode gas diffusion layer 14 can be elastically deformed in the direction from the thickness after compression by the fastening device 25 to the thickness before compression so as to follow the deformation of the anode gas diffusion layer 15, the anode catalyst layer 13, and the electrolyte membrane 11. This can maintain the contact between the cathode catalyst layer 12 and the cathode gas diffusion layer 14 appropriately.

Further, as the cathode gas diffusion layer 14, a member made of carbon fiber is used. For example, the porous carbon fiber sheet may be carbon paper, carbon cloth, carbon felt, or the like. The carbon fiber sheet may not be used as the substrate of the cathode gas diffusion layer 14. For example, sintered metal fibers made of titanium, titanium alloy, stainless steel, or the like, sintered metal particles made of these materials, or the like can be used as the base material of the cathode gas diffusion layer 14.

An anode gas diffusion layer 15 is provided on the anode catalyst layer 13. The anode gas diffusion layer 15 is made of a porous material and has electrical conductivity and gas diffusion properties. It is desirable that the anode gas diffusion layer 15 has high rigidity so that displacement and deformation of the member due to the pressure difference between the cathode CA and the anode AN can be suppressed during the hydrogen pressure increasing operation of the electrochemical hydrogen pump 100.

Here, fig. 3 is a diagram showing an example of the carbon porous body sheet in the electrochemical hydrogen pump according to embodiment 1.

The anode gas diffusion layer 15 includes a carbon porous sheet 15S containing carbon fibers and carbon materials other than carbon fibers, and the porosity of the 1 st surface layer 15B on the anode separator 17 side is larger than the porosity of the 2 nd surface layer 15A on the anode catalyst layer 13 side. In this case, the carbon porous sheet 15S may have a carbon density of the 1 st surface layer 15B lower than that of the 2 nd surface layer 15A.

In the carbon porous sheet 15S, the carbon material may be a carbide of a thermosetting resin. In this case, the carbon porous body sheet 15S may be, for example, a sintered body made of a thermosetting resin and carbon fibers. Specifically, the thermosetting resin is a resin that is composed of a polymer material that is polymerized by heating and that does not harden. Therefore, for example, if a carbon fiber sheet impregnated with a thermosetting resin is fired, a carbon fiber sheet 15S having high rigidity, high conductivity, and high gas diffusion properties including carbon fibers and carbides of the thermosetting resin can be obtained. Details will be described later.

Here, in the above-described carbon porous body sheet 15S, for example, the magnitude relationship of the porosity between the 1 st surface layer 15B and the 2 nd surface layer 15A can be appropriately set according to the difference in density of the carbon fibers contained in the carbon porous body sheet 15S. That is, in the carbon porous body sheet 15S of this example, the density of the carbon fibers of the 1 st surface layer 15B is lower than the density of the carbon fibers of the 2 nd surface layer 15A. This makes it possible to make the porosity of the 1 st surface layer 15B larger than the porosity of the 2 nd surface layer 15A.

In the above-described porous carbon sheet 15S, for example, the magnitude relationship of the porosity between the 1 st surface layer 15B and the 2 nd surface layer 15A can be appropriately set according to the difference in density of the carbon material contained in the porous carbon sheet 15S. That is, in the porous carbon sheet 15S of this example, the density of the carbon material of the 1 st surface layer 15B is lower than the density of the carbon material of the 2 nd surface layer 15A. Specifically, when the carbon porous sheet 15S is a fired body of a carbon fiber sheet impregnated with a thermosetting resin, for example, the higher the impregnation amount of the thermosetting resin in the carbon fiber sheet before firing, the higher the density of the carbon material after firing. Therefore, in the carbon porous body sheet 15S of this example, the impregnation amount of the thermosetting resin of the 1 st surface layer 15B before firing is smaller than the impregnation amount of the thermosetting resin of the 2 nd surface layer 15A.

The thermosetting resin is not limited to phenol resin, for example.

The pore diameter and porosity of the porous carbon sheet 15S can be evaluated by, for example, a mercury porosimeter (trade name: Autopore III 9410, manufactured by shimadzu corporation), but are not limited thereto. The mercury porosimeter can measure the volume of pores having a pore diameter of about several nm to 500 μm by injecting mercury into the pores. Further, the porosity of the 1 st surface layer 15B and the 2 nd surface layer 15A can be known from the volume of pores and the solid portion thereof.

In the electrochemical hydrogen pump 100 of the present embodiment, as shown in fig. 3, the carbon porous sheet 15S may be a laminate in which one main surface of the 1 st surface layer 15B is in contact with the main surface of the anode separator 17 and the other main surface of the 1 st surface layer 15B is in contact with one main surface of the 2 nd surface layer 15A. Also, as shown in fig. 3, the other main surface of the 2 nd surface layer 15A may be in contact with the anode catalyst layer 13.

The carbon porous sheet 15S in fig. 3 may be made of a single carbon fiber sheet or may be made of a plurality of carbon fiber sheets.

In the former case, the carbon porous sheet 15S can be obtained by impregnating only one surface of the carbon fiber sheet with a thermosetting resin before firing.

In the latter case, the carbon porous body sheet 15S can be obtained by laminating 2 carbon fiber sheets having different impregnation amounts of the thermosetting resin before firing. In this case, the number of carbon fiber sheets stacked may be 3 or more. For example, an intermediate layer (not shown) or the like, which contains a fired body of a thermosetting resin-impregnated carbon fiber sheet having a porosity smaller than that of the 1 st surface layer 15B and larger than that of the 2 nd surface layer 15A, may be provided between the carbon fiber sheet corresponding to the 1 st surface layer 15B and the carbon fiber sheet corresponding to the 2 nd surface layer 15A.

Next, an example of the SEM cross-sectional observation results of the carbon porous body sheet 15S in the electrochemical hydrogen pump 100 according to embodiment 1 will be described with reference to the drawings.

Fig. 4A, 4B, and 4C are views showing an example of SEM cross-sectional images of the carbon porous body sheet in the electrochemical hydrogen pump according to embodiment 1.

Fig. 4A shows an image of a partial cross section of the carbon porous body sheet 15S viewed at a magnification of 500 times. Fig. 4B shows a B-part enlarged image (2000 ×) in fig. 4A. Fig. 4C shows the enlarged image (5000 times) of the part C of fig. 4B.

The SEM cross-sectional observation was performed under the following electron gun conditions.

Acceleration voltage: 4kV

Emission current: SS40

Further, as the carbon porous sheet 15S, a carbon fiber sheet (trade name: トカレフレックス) manufactured by carbon Kasei K.K., containing carbon fibers and a carbon material (a carbide of a phenol resin-based thermosetting resin) was used.

As shown in fig. 4C, it was confirmed that carbides of the thermosetting resin (light portions in the figure) were present in gaps between the carbon fibers (dark portions in the figure). That is, since such carbides fill the gaps between the carbon fibers, the porosity of the carbon fiber sheet can be adjusted to a desired value by appropriately controlling the impregnation amount of the thermosetting resin impregnated into the carbon fiber sheet before firing.

The uppermost bright portion present above the portion B in fig. 4A is a damaged portion of the carbon fiber generated when the carbon fiber extending in a direction different from the direction in which the carbon fiber of the portion B extends is cut. The hollow portion (dark portion in the figure) present below the portion B in fig. 4A is a crack of the carbon fiber generated when the carbon fiber is cut.

The anode separator 17 is a member provided on the anode electrode AN. The cathode separator 16 is a member provided on the cathode electrode CA. A recess is provided in the center of each of cathode separator 16 and anode separator 17. The concave portions each accommodate therein a cathode gas diffusion layer 14 and an anode gas diffusion layer 15.

In this way, the MEA is sandwiched by the cathode separator 16 and the anode separator 17, whereby the hydrogen pump unit 100A is formed.

A serpentine cathode gas flow path 32 is provided in a plan view on a main surface of the cathode separator 16 that contacts the cathode gas diffusion layer 14, and the cathode gas flow path 32 includes, for example, a plurality of U-turn portions and a plurality of straight portions. Further, the straight line portion of the cathode gas flow field 32 extends in a direction perpendicular to the paper surface of fig. 1A. However, the cathode gas flow field 32 is merely an example and is not limited to this example. For example, the cathode gas flow path may be formed of a plurality of straight flow paths.

An anode gas flow path 33 having a serpentine shape in plan view is provided on a main surface of the anode separator 17 in contact with the anode gas diffusion layer 15, and the anode gas flow path 33 includes, for example, a plurality of U-turn portions and a plurality of straight portions. Further, the straight line portion of the anode gas flow field 33 extends in a direction perpendicular to the paper surface of fig. 2A. However, the anode gas flow field 33 is merely an example and is not limited to this example. For example, the anode gas flow path may be formed of a plurality of straight flow paths.

An annular flat plate-like insulator 21 is inserted between the conductive cathode separator 16 and the conductive anode separator 17 so as to surround the MEA. Thereby, short-circuiting of cathode separator 16 and anode separator 17 is prevented.

Here, the electrochemical hydrogen pump 100 includes: a 1 st end plate and a 2 nd end plate provided on both ends in the stacking direction in the hydrogen pump unit 100A; and a fastener 25 that fastens the hydrogen pump unit 100A, the 1 st end plate, and the 2 nd end plate in the stacking direction.

Further, in the example shown in fig. 1A and 2A, the cathode terminal plate 24C and the anode terminal plate 24A each correspond to the above-described 1 st terminal plate and 2 nd terminal plate, respectively. That is, the anode end plate 24A is an end plate provided on the anode diaphragm 17 located at one end in the stacking direction in which the respective members of the hydrogen pump unit 100A are stacked. The cathode end plate 24C is an end plate provided on the cathode separator 16 located at the other end in the stacking direction in which the respective members of the hydrogen pump unit 100A are stacked.

The fastener 25 may have various structures as long as the hydrogen pump unit 100A, the cathode end plate 24C, and the anode end plate 24A can be fastened in the stacking direction.

For example, the fastener 25 may be a bolt, a nut with a coil spring, or the like.

In this case, the bolts of the fasteners 25 may penetrate only the anode end plate 24A and the cathode end plate 24C, but in the electrochemical hydrogen pump 100 of the present embodiment, the bolts penetrate the members of the 3-stage hydrogen pump unit 100A, the cathode power supply plate 22C, the cathode insulating plate 23C, the anode power supply plate 22A, the anode insulating plate 23A, the anode end plate 24A, and the cathode end plate 24C. The end face of the cathode separator 16 located at the other end in the stacking direction and the end face of the anode separator 17 located at one end in the stacking direction are sandwiched between the cathode end plate 24C and the anode end plate 24A via the cathode power supply plate 22C and the cathode insulating plate 23C and the anode power supply plate 22A and the anode insulating plate 23A, respectively, and a predetermined fastening pressure is applied to the hydrogen pump unit 100A by the fastening device 25.

As described above, in the electrochemical hydrogen pump 100 of the present embodiment, the 3-stage hydrogen pump unit 100A is appropriately held in a stacked state in the stacking direction by the fastening pressure of the fastener 25, and the bolts of the fastener 25 penetrate the respective members of the electrochemical hydrogen pump 100, so that the movement in the in-plane direction of the respective members can be appropriately suppressed.

Here, in the electrochemical hydrogen pump 100 of the present embodiment, a cathode gas flow path 32 through which cathode gas (hydrogen) flowing out from each cathode gas diffusion layer 14 of the hydrogen pump cell 100A flows is communicated. Hereinafter, a structure in which the cathode gas flow paths 32 communicate with each other will be described with reference to the drawings.

First, as shown in fig. 1A, the cathode gas lead-out manifold 50 is configured by connecting through-holes provided in the members of the 3-stage hydrogen pump unit 100A and the cathode end plate 24C, and non-through-holes provided in the anode end plate 24A. Further, a cathode gas lead-out passage 26 is provided in the cathode end plate 24C. The cathode gas lead-out path 26 may be formed by hydrogen (H) discharged from the cathode electrode CA₂) A piping for circulation. The cathode gas discharge path 26 communicates with the cathode gas discharge manifold 50.

The cathode gas lead-out manifold 50 is in communication with one end of each cathode gas flow path 32 of the hydrogen pump unit 100A via each of the cathode gas passage paths 34. Thus, the hydrogen passing through the cathode gas flow paths 32 and the cathode gas passage 34 of the hydrogen pump unit 100A are merged at the cathode gas discharge manifold 50. The merged hydrogen is guided to the cathode gas lead-out passage 26.

In this way, the cathode gas flow paths 32 of the hydrogen pump unit 100A communicate with the cathode gas lead-out manifold 50 via the cathode gas passage paths 34 of the hydrogen pump unit 100A.

Annular sealing members 40 such as O-rings are provided between the cathode separator 16 and the anode separator 17, between the cathode separator 16 and the cathode power supply plate 22C, and between the anode separator 17 and the anode power supply plate 22A so as to surround the cathode gas discharge manifold 50 in plan view, and the cathode gas discharge manifold 50 is appropriately sealed by the sealing members 40.

As shown in fig. 2A, an anode gas introduction path 29 is provided in the anode end plate 24A. The anode gas introduction path 29 may be constituted by a pipe through which the anode gas to be supplied to the anode electrode AN flows. Examples of the anode gas include a hydrogen-containing gas containing water vapor. The anode gas introduction passage 29 communicates with the cylindrical anode gas introduction manifold 27. The anode gas inlet manifold 27 is formed by connecting the members of the 3-stage hydrogen pump unit 100A and the through-holes provided in the anode end plate 24A.

In addition, the anode gas introduction manifold 27 communicates with each of the 1 st anode gas passage paths 35 via one end portion of each of the anode gas flow paths 33 of the hydrogen pump unit 100A. Thereby, the anode gas supplied from the anode gas introduction path 29 to the anode gas introduction manifold 27 is distributed to each hydrogen pump cell 100A through each 1 st anode gas passage path 35 of the hydrogen pump cell 100A. Then, while the dispensed anode gas passes through the anode gas flow passage 33, the anode gas is supplied from the anode gas diffusion layer 15 to the anode catalyst layer 13.

As shown in fig. 2A, the anode end plate 24A is provided with an anode gas lead-out passage 31. The anode gas lead-out path 31 may be constituted by a pipe through which the anode gas discharged from the anode electrode AN flows. The anode gas discharge passage 31 communicates with the cylindrical anode gas discharge manifold 30. The anode gas lead-out manifold 30 is formed by connecting each member provided in the 3-stage hydrogen pump unit 100A to a through hole of the anode end plate 24A.

The anode gas lead-out manifold 30 communicates with the other end portions of the anode gas flow paths 33 of the hydrogen pump unit 100A via the 2 nd anode gas passage paths 36. Thus, the anode gases having passed through the anode gas flow paths 33 of the hydrogen pump unit 100A are supplied to the anode gas discharge manifold 30 through the 2 nd anode gas passage paths 36, and join there. Then, the merged anode gas is guided to the anode gas lead-out passage 31.

An annular sealing member 40 such as an O-ring is provided between the cathode separator 16 and the anode separator 17, between the cathode separator 16 and the cathode power supply plate 22C, and between the anode separator 17 and the anode power supply plate 22A so as to surround the anode gas introduction manifold 27 and the anode gas discharge manifold 30 in plan view, and the anode gas introduction manifold 27 and the anode gas discharge manifold 30 are appropriately sealed by the sealing member 40.

As shown in fig. 1A and 2A, the electrochemical hydrogen pump 100 is provided with a voltage applicator 102.

The voltage applicator 102 is a device that applies a voltage between the anode catalyst layer 13 and the cathode catalyst layer 12. That is, the electrochemical hydrogen pump 100 is a device that moves hydrogen in the hydrogen-containing gas supplied to the anode catalyst layer 13 to the cathode catalyst layer 12 by applying the voltage from the voltage applicator 102, and raises the pressure.

Specifically, a high potential of the voltage applier 102 is applied to the anode catalyst layer 13, and a low potential of the voltage applier 102 is applied to the cathode catalyst layer 12. The voltage applicator 102 may have various structures as long as it can apply a voltage between the anode catalyst layer 13 and the cathode catalyst layer 12. For example, the voltage applicator 102 may be a device that adjusts the voltage applied between the anode catalyst layer 13 and the cathode catalyst layer 12. In this case, the voltage applicator 102 includes a DC/DC converter when connected to a DC power supply such as a battery, a solar cell, or a fuel cell, and an AC/DC converter when connected to an AC power supply such as a commercial power supply.

The voltage applicator 102 may be, for example, a power type power supply that adjusts a voltage applied between the anode catalyst layer 13 and the cathode catalyst layer 12 and a current flowing between the anode catalyst layer 13 and the cathode catalyst layer 12 so that the power supplied to the hydrogen pump cell 100A becomes a predetermined set value.

Further, in the example shown in fig. 1A and 2A, the terminal on the low potential side of the voltage applier 102 is connected to the cathode power supply plate 22C, and the terminal on the high potential side of the voltage applier 102 is connected to the anode power supply plate 22A. The cathode feeding plate 22C is in electrical contact with the cathode separator 16 located at the other end in the stacking direction, and the anode feeding plate 22A is in electrical contact with the anode separator 17 located at one end in the stacking direction.

Although not shown, a hydrogen supply system including the electrochemical hydrogen pump 100 may be constructed. In this case, the equipment necessary for the hydrogen supply operation of the hydrogen supply system is appropriately provided.

For example, the hydrogen supply system may be provided with a dew point adjuster (e.g., a humidifier) for adjusting a dew point of a mixed gas in which the high humidified state hydrogen-containing anode gas discharged from the anode electrode AN through the anode gas discharge passage 31 and the low humidified state hydrogen-containing anode gas supplied from the external hydrogen supply source through the anode gas introduction passage 29 are mixed. In this case, the hydrogen-containing anode gas of the external hydrogen supply source may be generated by, for example, a water electrolysis device.

The hydrogen supply system may be provided with, for example, a temperature detector for detecting the temperature of the electrochemical hydrogen pump 100, a hydrogen storage device for temporarily storing hydrogen discharged from the cathode electrode CA of the electrochemical hydrogen pump 100, a pressure detector for detecting the pressure of hydrogen gas in the hydrogen storage device, and the like.

The configuration of the electrochemical hydrogen pump 100 and various devices not shown in the drawings in the hydrogen supply system are merely examples, and are not limited to this example.

For example, hydrogen (H) in the anode gas supplied to the anode electrode AN through the anode gas introduction manifold 27 may be used without providing the anode gas introduction manifold 30 and the anode gas introduction path 31₂) The total amount of (c) is in a dead-end configuration where the cathode electrode CA is boosted.

[ actions ]

An example of the hydrogen pressure increasing operation of the electrochemical hydrogen pump 100 will be described below with reference to the drawings.

The following operations can be executed by, for example, an arithmetic circuit of a controller not shown reading a control program from a memory circuit of the controller. However, it is not necessary that the following actions be performed with the controller. The operator may perform some of its actions. In the following, a case will be described in which a hydrogen-containing gas containing water vapor is supplied as AN anode gas to the anode electrode AN of the electrochemical hydrogen pump 100.

First, a low-pressure hydrogen-containing gas is supplied to the anode electrode AN of the electrochemical hydrogen pump 100, and the voltage of the voltage applicator 102 is supplied to the electrochemical hydrogen pump 100.

Then, in the anode catalyst layer 13 of the anode electrode AN, hydrogen molecules are separated into hydrogen ions (protons) and electrons by AN oxidation reaction (formula (1)). The protons are conducted in the electrolyte membrane 1 and move toward the cathode catalyst layer 2C. The electrons move toward the cathode catalyst layer 2C of the cathode through the voltage applicator 102.

Then, in the cathode catalyst layer 2C, hydrogen molecules (formula (2)) are generated again by a reduction reaction. It is known that when protons are conducted through the electrolyte membrane 1, a predetermined amount of water moves as electric seepage water from the anode electrode AN to the cathode electrode CA together with the protons.

At this time, the pressure loss in the hydrogen discharge path can be increased by using a flow rate controller (not shown) to increase the hydrogen (H) generated at the cathode electrode CA₂) The pressure of (a). The hydrogen discharge path may be, for example, the cathode gas discharge path 26 shown in fig. 2A. Examples of the flow rate regulator include a back pressure valve and an adjustment valve provided in the hydrogen discharge path.

Anode electrode: h₂(Low pressure) → 2H⁺+2e-...(1)

Cathode electrode: 2H⁺+2e-→H₂(high pressure)

In this way, in the electrochemical hydrogen pump 100, the voltage is applied by the voltage applicator 102, and the pressure of hydrogen in the hydrogen-containing gas supplied to the anode electrode AN is increased at the cathode electrode CA. Thereby, the hydrogen pressure increasing operation of the electrochemical hydrogen pump 100 is performed, and the hydrogen increased in pressure at the cathode electrode CA is temporarily stored in, for example, a hydrogen storage device not shown. In addition, the hydrogen stored in the hydrogen storage is supplied to the hydrogen requiring body in time. Examples of the hydrogen-requiring substance include a fuel cell that generates electricity using hydrogen.

Here, for example, when AN electric current flows between the anode electrode AN and the cathode electrode CA of the electrochemical hydrogen pump 100, protons move from the anode electrode AN to the cathode electrode CA in the electrolyte membrane 11 along with water. At this time, when the operating temperature of the electrochemical hydrogen pump 100 is equal to or higher than the predetermined temperature, the water (electro-osmotic water) transferred from the anode electrode AN to the cathode electrode CA exists in the form of water vapor, and the proportion of the water in the form of liquid water increases as the hydrogen pressure of the cathode electrode CA increases. Also, in the case where liquid water is present at the cathode electrode CA, a part of the water is pushed back to the anode electrode AN due to a pressure difference between the cathode electrode CA and the anode electrode AN, and the higher the hydrogen pressure of the cathode electrode CA is, the more the amount of water pushed back to the anode electrode AN increases. Then, as the hydrogen pressure of the cathode electrode CA rises, the water pushed back to the anode electrode AN easily overflows the anode gas diffusion layer 15 of the anode electrode AN. In addition, since such flooding occurs, the gas diffusibility is impaired at the anode electrode AN, and in this case, the diffusion resistance of the electrochemical hydrogen pump 100 increases, and the efficiency of the hydrogen pressure increasing operation of the electrochemical hydrogen pump 100 may be lowered.

Therefore, as described above, in the electrochemical hydrogen pump 100 according to the present embodiment, the anode gas diffusion layer 15 includes the carbon porous sheet 15S, the carbon porous sheet 15S includes carbon fibers and a carbon material different from the carbon fibers, and the porosity of the 1 st surface layer 15B on the anode separator 17 side is larger than the porosity of the 2 nd surface layer 15A on the anode catalyst layer 13 side. Therefore, the electrochemical hydrogen pump 100 of the present embodiment can suppress the occurrence of flooding due to water in the anode gas diffusion layer 15 more than ever.

Specifically, by increasing the porosity of the 1 st surface layer 15B on the anode separator 17 side of the porous carbon sheet 15S, the water present in the porous carbon sheet 15S can be easily discharged to the outside of the porous carbon sheet 15S by, for example, the flow of the hydrogen-containing gas in the porous carbon sheet 15S. In addition, by reducing the porosity of the 2 nd surface layer 15A on the anode catalyst layer 13 side of the carbon porous body sheet 15S, it is possible to suppress water pushed back to the anode due to the pressure difference between the cathode electrode CA and the anode electrode AN from passing through the 2 nd surface layer 15A.

As described above, the electrochemical hydrogen pump 100 according to the present embodiment can suppress the occurrence of flooding due to water in the anode gas diffusion layer 15, and as a result, can appropriately maintain the gas diffusibility in the anode AN.

In the electrochemical hydrogen pumps of patent documents 1 and 2, the gas diffusion layer is made of a metal material such as titanium. When the gas diffusion layer is made of a metal material such as titanium, it is necessary to perform surface plating using a noble metal such as platinum. This is due to the following reason.

When the gas diffusion layer is made of a metal material such as titanium, the metal material is in contact with the proton-conductive electrolyte membrane via the catalyst layer. In order to obtain proton conductivity, the electrolyte membrane (polymer membrane) often has a sulfate group as a side chain. When the hydrogen-containing gas in a wet state is supplied to the gas diffusion layer, the metal material comes into contact with strongly acidic moisture, and metal ions may be eluted from the metal material into the moisture.

That is, when the gas diffusion layer is made of a metal material, it is necessary to suppress elution of metal ions in an acidic state of the gas diffusion layer. For example, a conductive coating is often formed on the surface of such a metal material by performing surface plating on the surface of the metal material with a noble metal that is less likely to cause ion elution in an acidic state. This causes an increase in the cost of the electrochemical hydrogen pump. Further, the method of forming an oxide film on the surface of the metal material is not desirable because the electrical conductivity of the gas diffusion layer is lowered.

Therefore, the inventors have studied using a carbon-based gas diffusion layer having corrosion resistance under an acidic environment and low cost in order to suppress elution of metal ions in the gas diffusion layer under an acidic environment, and have found a problem that the anode gas diffusion layer 15 is bent in the anode gas flow passage 33 provided in the anode separator 17 due to the influence of the pressure in the cathode CA.

In view of the above problem, in the electrochemical hydrogen pump 100 of the present embodiment, the carbon porous sheet 15S is formed of a sintered body of a carbon fiber sheet impregnated with a thermosetting resin, as described above. For example, the carbon fiber sheet impregnated with the thermosetting resin may be previously fired in a reducing atmosphere filled with nitrogen gas or the like.

As described above, in the electrochemical hydrogen pump 100 of the present embodiment, the thermosetting resin is carbonized by firing, and thereby the carbon material and the carbon fiber are reinforced with each other, so that high rigidity of the carbon porous body sheet 15S can be achieved. Thus, the deformation of the carbon porous body sheet 15S due to the pressure difference between the cathode electrode CA and the anode electrode AN generated during the hydrogen pressure increasing operation of the electrochemical hydrogen pump 100 is suppressed. For example, the electrochemical hydrogen pump 100 of the present embodiment can reduce the possibility that the carbon porous sheet 15S is bent in the anode gas flow path 33 provided in the anode separator 17 due to the above-described pressure difference.

The electrochemical hydrogen pump 100 of the present embodiment can obtain a carbide conductor by burning and carbonizing a thermosetting resin. Thus, in the electrochemical hydrogen pump 100 of the present embodiment, since the conductor is in contact with the carbon fibers, high conductivity of the carbon porous sheet 15S can be achieved.

In addition, the electrochemical hydrogen pump 100 of the present embodiment is configured to easily form pores (communicating pores) communicating with the outside in the carbon porous body sheet 15S by burning and carbonizing a thermosetting resin, and thus can realize high gas diffusivity of the carbon porous body sheet 15S.

In addition, the electrochemical hydrogen pump 100 of the present embodiment can reduce the organic component in the moisture of the hydrogen-containing gas derived from the thermosetting resin by firing the carbon fiber sheet impregnated with the thermosetting resin in advance. That is, the organic component eluted into the moisture of the hydrogen-containing gas may become a contaminant component that inhibits the reactivity of the anode catalyst layer 13 and the cathode catalyst layer 12, the proton conductivity of the electrolyte membrane 11, and the like, but the electrochemical hydrogen pump 100 of the present embodiment can reduce such a problem by the above-described configuration.

(embodiment 2)

Fig. 5 is a diagram showing an example of the carbon porous body sheet in the electrochemical hydrogen pump according to embodiment 2.

The electrochemical hydrogen pump 100 of the present embodiment is the same as the electrochemical hydrogen pump 100 of embodiment 1, except for the configuration and the manufacturing method of the carbon porous body sheet 15S and the configuration of the anode separator 17, which are described below.

In the electrochemical hydrogen pump 100 of the present embodiment, as shown in fig. 5, the porous carbon sheet 15S has a flow path 33A through which the hydrogen-containing gas flows in the 1 st surface layer 15B. That is, instead of the anode gas flow channels 33 provided in the anode separator 17 (see fig. 1B and 2B), the flow channels 33A are provided in the 1 st surface layer 15B of the carbon porous body sheet 15S.

For example, the flow paths 33A may be formed in the carbon porous sheet 15S as described below by stacking a plurality of carbon fiber sheets having different porosities. The plurality of carbon fiber sheets may be carbon fiber sheets having different carbon fiber densities, for example.

The number of carbon fiber sheets stacked in fig. 5 is merely an example, and is not limited to this example. For example, an intermediate layer (not shown) may be provided between the carbon fiber sheet corresponding to the 1 st surface layer 15B and the carbon fiber sheet corresponding to the 2 nd surface layer 15A, the intermediate layer including a fired body of the thermosetting resin-impregnated carbon fiber sheet, the intermediate layer having a porosity smaller than that of the 1 st surface layer 15B and larger than that of the 2 nd surface layer 15A.

First, a slit forming process for forming the flow path 33A is performed by using an appropriate mold (not shown) for a carbon fiber sheet having a low carbon fiber density (hereinafter referred to as the 1 st carbon fiber sheet), for example, so as to look like a serpentine shape in plan view.

Next, a thermosetting resin was applied to the surface of the 1 st carbon fiber sheet. Then, the thermosetting resin is impregnated from the part of the surface of the 1 st carbon fiber sheet where the slits are not formed. Further, at this time, the fluidity of the thermosetting resin is appropriately set so that the slits of the 1 st carbon fiber sheet are not sealed with the thermosetting resin.

Next, a thermosetting resin is applied to the surface of a carbon fiber sheet having a high density of carbon fibers (hereinafter referred to as a 2 nd carbon fiber sheet). Then, the entire surface of the 2 nd carbon fiber sheet is impregnated with the thermosetting resin.

Next, the 1 st carbon fiber sheet impregnated with the thermosetting resin and the 2 nd carbon fiber sheet impregnated with the thermosetting resin are superposed. Then, the 1 st carbon fiber sheet and the 2 nd carbon fiber sheet are bonded by polymerization of the thermosetting resins of both.

Next, the laminate of the 1 st carbon fiber sheet and the 2 nd carbon fiber sheet is fired in a reducing atmosphere filled with nitrogen gas or the like, for example.

In this way, the carbon porous body sheet 15S of fig. 5 is obtained. That is, the fired body of the 1 st carbon fiber sheet impregnated with the thermosetting resin corresponds to the 1 st surface layer 15B on the anode separator 17 side of the carbon porous sheet 15S in fig. 5. The fired body of the 2 nd carbon fiber sheet impregnated with the thermosetting resin corresponds to the 2 nd surface layer 15A on the anode catalyst layer 13 side of the carbon porous body sheet 15S in fig. 5.

The above methods for producing the carbon porous sheet 15S and the structure thereof are examples, and are not limited to this example.

As described above, in the electrochemical hydrogen pump 100 of the present embodiment, the flow channel 33A is provided in the 1 st surface layer 15B on the anode separator 17 side of the porous carbon sheet 15S, so that, for example, the hydrogen-containing gas flows through the porous carbon sheet 15S, and water present in the flow channel 33A is easily discharged to the outside of the porous carbon sheet 15S. Thus, in the electrochemical hydrogen pump 100 of the present embodiment, the occurrence of flooding due to water in the anode gas diffusion layer 15 is suppressed, and as a result, the gas diffusibility can be appropriately maintained in the anode AN.

In the electrochemical hydrogen pump 100 of the present embodiment, the flow path 33A through which the hydrogen-containing gas flows is easily provided in the 1 st surface layer 15B on the anode separator 17 side of the porous carbon sheet 15S by, for example, die molding. Therefore, in the electrochemical hydrogen pump 100 of the present embodiment, the flow path is more easily formed than in the case where the flow path through which the hydrogen-containing gas flows is cut into the metal anode separator 17, for example.

The electrochemical hydrogen pump 100 of the present embodiment may be the same as the electrochemical hydrogen pump 100 of embodiment 1, except for the above-described features.

(embodiment 3)

Fig. 6A is a diagram showing an example of the carbon porous body sheet in the electrochemical hydrogen pump according to embodiment 3.

The carbon porous sheet 15S of the electrochemical hydrogen pump 100 of embodiment 3 is the same as the electrochemical hydrogen pump 100 of embodiment 1, except that the surface layer 115A of embodiment 2 includes the water-repellent layer 15H.

As described above, as the hydrogen pressure of the cathode electrode CA increases, flooding is easily generated at the anode gas diffusion layer 15 of the anode electrode AN due to the water pushed back to the anode electrode AN.

Therefore, in the electrochemical hydrogen pump 100 according to the present embodiment, the hydrophobic layer 15H included in the 2 nd surface layer 115A on the anode catalyst layer 13 side imparts hydrophobicity to the porous carbon sheet 15S. For example, when the 2 nd surface layer 115A is a sintered body made of carbon fibers, the carbon porous sheet 15S may be configured such that the 2 nd surface layer 115A includes the water-repellent layer 15H by impregnating the sintered body with a material including a hydrophobic resin such as a fluorine-based resin, as shown in fig. 6A. Accordingly, the water pushed back to the anode electrode AN by the pressure difference between the cathode electrode CA and the anode electrode AN can be quickly discharged to the outside by the flow of the hydrogen-containing gas in the water-repellent layer 15H. Therefore, in the electrochemical hydrogen pump 100 of the present embodiment, the occurrence of flooding due to water in the anode gas diffusion layer 15 is suppressed, and as a result, the gas diffusibility can be appropriately maintained in the anode AN.

Examples of the material containing the hydrophobic resin include a solution in which a PTFE fine powder is dispersed in a solvent.

In addition, the water-repellent layer 15H may be a layer containing a hydrophobic resin and carbon black. In this case, the water-repellent layer 15H contained in the 2 nd surface layer 115A is formed by impregnating the 2 nd surface layer 115A with a material containing a hydrophobic resin and carbon black. Examples of the material containing the hydrophobic resin and carbon black include a solution in which fine particles of PTFE and carbon black are dispersed in a solvent. Thus, the hydrophobic layer 15H contains a hydrophobic resin and carbon black, and the hydrophobicity of the anode gas diffusion layer 15 can be appropriately expressed.

The above-described method for producing the water-repellent layer 15H and the structure thereof are examples, and are not limited to this example.

The electrochemical hydrogen pump 100 of the present embodiment may be the same as the electrochemical hydrogen pump 100 of embodiment 1 or embodiment 2, except for the above-described features.

(modification example)

Fig. 6B is a diagram showing an example of a carbon porous body sheet in the electrochemical hydrogen pump according to the modification of embodiment 3.

The carbon porous sheet 15S of the electrochemical hydrogen pump 100 according to the present modification is the same as the electrochemical hydrogen pump 100 according to embodiment 1, except that the water-repellent layer 15H is provided on the 2 nd surface layer 115A.

In the electrochemical hydrogen pump 100 according to this modification, the hydrophobic layer 15H provided on the 2 nd surface layer 115A on the anode catalyst layer 13 side imparts hydrophobicity to the porous carbon sheet 15S. For example, the water-repellent layer 15H may be formed on the 2 nd surface layer 115A as shown in fig. 6B by applying a material containing a hydrophobic resin such as a fluorine-based resin to the 2 nd surface layer 115A. Accordingly, the water pushed back to the anode electrode AN by the pressure difference between the cathode electrode CA and the anode electrode AN can be quickly discharged to the outside by the flow of the hydrogen-containing gas in the water-repellent layer 15H. Therefore, in the electrochemical hydrogen pump 100 of the present embodiment, the occurrence of flooding due to water in the anode gas diffusion layer 15 is suppressed, and as a result, the gas diffusibility can be appropriately maintained in the anode AN.

Examples of the material containing the hydrophobic resin include a solution in which a PTFE fine powder is dispersed in a solvent. Further, as a method for coating a material containing a hydrophobic resin, for example, a spray coating method and the like can be given.

In addition, the water-repellent layer 15H may be a layer containing a hydrophobic resin and carbon black. In this case, the water-repellent layer 15H is formed on the 2 nd surface layer 115A by coating a material containing a hydrophobic resin and carbon black on the 2 nd surface layer 115A. Examples of the material containing the hydrophobic resin and the carbon black include a solution in which PTFE fine powder and carbon black are dispersed in a solvent. Further, as a method for coating a material containing a hydrophobic resin and carbon black, for example, a spray coating method and the like can be given. Thus, the hydrophobic layer 15H contains a hydrophobic resin and carbon black, and the hydrophobicity of the anode gas diffusion layer 15 can be appropriately expressed.

The above-described method for producing the water-repellent layer 15H and the structure thereof are examples, and are not limited to this example.

The electrochemical hydrogen pump 100 of the present modification may be the same as the electrochemical hydrogen pump 100 of embodiment 1 or embodiment 2, except for the above-described features.

Further, modifications of embodiment 1, embodiment 2, embodiment 3, and embodiment 3 may be combined with each other as long as they do not exclude each other.

Numerous modifications and other embodiments of the disclosure will be apparent to those skilled in the art to which the disclosure pertains. Accordingly, the foregoing description is to be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the disclosure. The operating conditions, compositions, structures and/or functions can be substantially changed without departing from the spirit of the present disclosure.

Industrial applicability

The present disclosure can be used for an electrochemical hydrogen pump that can suppress the occurrence of flooding due to water in an anode gas diffusion layer more than before.

Description of the reference numerals

11: electrolyte membrane

12: cathode catalyst layer

13: anode catalyst layer

14: cathode gas diffusion layer

15: anode gas diffusion layer

15A: 2 nd surface layer

15B: 1 st surface layer

15H: hydrophobic layer

15S: carbon porous sheet

16: cathode separator

17: anode diaphragm

21: insulator

22A: anode power supply plate

22C: cathode power supply plate

23A: anode insulating plate

23C: cathode insulating plate

24A: anode end plate

24C: cathode end plate

25: fastening device

26: cathode gas discharge path

27: anode gas introduction manifold

29: anode gas introduction path

30: anode gas lead-out manifold

31: anode gas lead-out path

32: cathode gas flow path

33: anode gas flow path

33A: flow path

34: cathode gas passage path

35: 1 st anode gas passing route

36: 2 nd anode gas passing path

40: sealing member

42: sealing member

43: sealing member

50: cathode gas lead-out manifold

100: electrochemical hydrogen pump

100A: hydrogen pump unit

102: voltage applicator

115A: 2 nd surface layer

AN: anode electrode

CA: cathode electrode