CARBON DIOXIDE ELECTROLYSIS CELL AND CARBON DIOXIDE ELECTROLYSIS DEVICE

Description

CROSS-REFERENCE TO RELATED APPLICATION

Priority is claimed on Japanese Patent Application No. 2023-058247, filed Mar. 31, 2023, the content of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a carbon dioxide electrolysis cell and a carbon dioxide electrolysis device.

Description of Related Art

A technology to obtain valuable resources by electrochemical reduction of exhaust gases and carbon dioxide in the atmosphere is a promising technology that has a possibility of achieving carbon neutrality, but the biggest issue is economic efficiency. In order to improve economic efficiency, it is important to reduce loss as much as possible and electrolyze carbon dioxide with high energy efficiency.

As the technique for electrochemically reducing carbon dioxide, a carbon dioxide electrolysis device that includes a gas supply flow path for supplying carbon dioxide to a cathode, and supplies raw material carbon dioxide in a gaseous state and electrochemically reduces it is known (Patent Document 1).

PATENT DOCUMENTS

[Patent Document 1] Japanese Unexamined Patent Application, First Publication No. 2022-141239

SUMMARY OF THE INVENTION

As the technique for electrochemically reducing carbon dioxide, a raw material solution supply type carbon dioxide electrolysis cell that supplies an electrolyte containing carbon dioxide being a raw material in an ionic state (CO₂³⁻) to a cathode is conceivable. Such a carbon dioxide electrolysis cell has a pressure loss specific to an electrolysis cell, and there is a limit to the flow rate at which the electrolyte flows. Therefore, a carbon dioxide electrolysis cell with a flow path plate in which a flow path for a raw material meanders and which has a long flow path length (for example, refer to Patent Document 1) is not considered suitable.

On the other hand, since the flow rate of the electrolyte greatly affects the discharge of the produced gas, there is a demand for a large flow rate.

Considering the production cost of carbon dioxide electrolysis cells, it is desirable to increase the area of each electrode, and thus it is very painful to limit the flow path length. Therefore, by configuring the electrolyte to flow in a direction perpendicular to the longitudinal direction of the electrode, the electrode area can be increased without extending the flow path length. However, in a configuration where the electrolyte flows in a direction perpendicular to the longitudinal direction of the electrode, it is necessary to take measures to distribute the raw material fluid uniformly to electrodes.

An object of the present invention is to provide a carbon dioxide electrolysis cell and a carbon dioxide electrolysis device in which the amount of a raw material fluid supplied to electrodes is highly uniform.

The present invention includes the following aspects.

Aspect 1 of the present invention is a raw material solution supply type carbon dioxide electrolysis cell, including a cathode section having a cathode-side solution flow path, an anode section having an anode-side solution flow path, and a diaphragm arranged between the cathode section and the anode section, wherein the cathode section includes a cathode including a gas diffusion layer and a cathode catalyst layer, and a cathode-side solution flow path forming member that forms a cathode-side solution flow path between itself and the cathode, wherein the anode section includes an anode and an anode-side solution flow path forming member that forms an anode-side solution flow path between itself and the anode, wherein both the cathode-side solution flow path forming member and the anode-side solution flow path forming member have a rectangular shape in a plan view in the direction in which the cathode section, the diaphragm and the anode section are stacked, wherein, at one end of the cathode-side solution flow path forming member, which is one short side of the pair of opposing short sides of the rectangular shape, a plurality of cathode-side solution supply holes for supplying a cathode-side solution to the cathode-side solution flow path are provided, and at the other end of the cathode-side solution flow path forming member, which is the other short side of the pair of the opposing short sides, a plurality of cathode-side solution discharge holes for discharging a cathode-side solution are provided, wherein, at one end of the anode-side solution flow path forming member, which is one short side of the pair of opposing short sides of the rectangular shape, a plurality of anode-side solution supply holes for supplying an anode-side solution to the anode-side solution flow path are provided, and at the other end of the anode-side solution flow path forming member, which is the other short side of the pair of the opposing short sides, a plurality of anode-side solution discharge holes for discharging an anode-side solution are provided, and wherein, in a plan view in the stacking direction, the plurality of cathode-side solution supply holes and the plurality of anode-side solution supply holes are arranged alternately, and the plurality of cathode-side solution discharge holes and the plurality of anode-side solution discharge holes are arranged alternately.

Aspect 2 of the present invention is the carbon dioxide electrolysis cell of Aspect 1, wherein the order in which the plurality of cathode-side solution discharge holes and the plurality of anode-side solution discharge holes are arranged alternately is opposite to the order in which the plurality of cathode-side solution supply holes and the plurality of anode-side solution supply holes are arranged alternately, wherein the plurality of cathode-side solution supply holes and the plurality of cathode-side solution discharge holes are arranged at mutually shifted positions on the pair of the opposing short sides, and wherein the plurality of anode-side solution supply holes and the plurality of anode-side solution discharge holes are arranged at mutually shifted positions on the pair of the opposing short sides.

Aspect 3 of the present invention is a carbon dioxide electrolysis device including the carbon dioxide electrolysis cell according to Aspect 1 or 2, a first power supplying body, a second power supplying body, and a power source device.

Aspect 4 of the present invention is a carbon dioxide electrolysis device including the plurality of carbon dioxide electrolysis cells according to Aspect 1 or 2, and further including a first power supplying body, a second power supplying body, and a power source device.

Aspect 5 of the present invention is the carbon dioxide electrolysis device of Aspect 4, wherein cathode-side solution supply manifolds that supply a cathode-side solution to the cathode-side solution flow path of the plurality of carbon dioxide electrolysis cells and anode-side solution supply manifolds that supply an anode-side solution to the anode-side solution flow path of the plurality of carbon dioxide electrolysis cells are arranged alternately, wherein cathode-side solution discharge manifolds that discharge a cathode-side solution from the cathode-side solution flow path of the plurality of carbon dioxide electrolysis cells and anode-side solution discharge manifolds that discharge an anode-side solution from the anode-side solution flow path of the plurality of carbon dioxide electrolysis cells are arranged alternately, wherein the order in which the plurality of cathode-side solution discharge holes and the plurality of anode-side solution discharge holes are arranged alternately is opposite to the order in which the plurality of cathode-side solution supply holes and the plurality of anode-side solution supply holes are arranged alternately, wherein the plurality of cathode-side solution supply holes and the plurality of cathode-side solution discharge holes are arranged at mutually shifted positions on the pair of the opposing short sides, and wherein the plurality of anode-side solution supply holes and the plurality of anode-side solution discharge holes are arranged at mutually shifted positions on the pair of the opposing short sides.

According to Aspect 1 to Aspect 5, it is possible to provide a carbon dioxide electrolysis cell and a carbon dioxide electrolysis device in which the amount of a raw material fluid supplied to electrodes is highly uniform.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view of a carbon dioxide electrolysis cell according to an embodiment.

FIG. 2 is a schematic cross-sectional view of a part of a cathode section side of the carbon dioxide electrolysis cell cut in a direction in which an electrolyte flows.

FIG. 3A is a schematic plan view showing a conventional typical structure example of a cathode-side solution flow path forming member or an anode-side solution flow path forming member.

FIG. 3B is a schematic plan view showing another conventional typical structure example of a cathode-side solution flow path forming member or an anode-side solution flow path forming member.

FIG. 4 is a schematic plan view of the cathode-side solution flow path forming member included in the carbon dioxide electrolysis cell according to the embodiment.

FIG. 5 is a schematic plan view of the anode-side solution flow path forming member included in the carbon dioxide electrolysis cell according to the embodiment.

FIG. 6 is a schematic cross-sectional view of a carbon dioxide electrolysis device 100 including a single carbon dioxide electrolysis cell 10.

FIG. 7 is a schematic cross-sectional view of a carbon dioxide electrolysis device 110 including a plurality of carbon dioxide electrolysis cells 10.

FIG. 8A is a perspective view of a configuration of the carbon dioxide electrolysis device 110 shown in FIG. 7 in which a plurality of carbon dioxide electrolysis cells 10 are arranged apart from each other.

FIG. 8B is a perspective view showing arrangement of a manifold (not shown in FIG. 7) included in the carbon dioxide electrolysis device 110 shown in FIG. 7.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Here, dimensions and the like of exemplified drawings in the following description are only examples, and the present invention is not necessarily limited thereto, but can be appropriately changed and implemented within ranges in which the scope and spirit of the invention are not changed.

FIG. 1 is a schematic cross-sectional view of a carbon dioxide electrolysis cell according to an embodiment. FIG. 2 is a schematic cross-sectional view of a part of a cathode section side of the carbon dioxide electrolysis cell cut in a direction in which an electrolyte flows.

A carbon dioxide electrolysis cell 10 shown in FIG. 1 is a raw material solution supply type carbon dioxide electrolysis cell, and includes a cathode section 20 having a cathode-side solution flow path, an anode section 30 having an anode-side solution flow path, and a diaphragm 40 arranged between the cathode section 20 and the anode section 30.

The cathode section 20 includes a cathode 21, and a cathode-side solution flow path forming member (cathode-side separator) 24 that forms a cathode-side solution flow path 22 between itself and the cathode 21.

The cathode 21 is an electrode (reduction electrode) that reduces carbon dioxide (CO₂) to produce a carbon compound and reduces water to produce hydrogen. Examples of carbon compounds produced according to a reduction reaction of carbon dioxide include carbon monoxide (CO), methane (CH₄), ethane (C₂H₆), ethylene (C₂H₄), methanol (CH₃OH), ethanol (C₂H₅OH), and ethylene glycol (C₂H₆O₂).

For example, according to the following reaction, carbon monoxide and ethylene are produced as gaseous products. In the cathode 21, hydrogen is also produced according to the following reaction.

CO₂+H₂O→CO+2OH⁻

2CO+8H₂O→C₂H₄+8OH⁻+2H₂O

2H₂O→H₂+2OH⁻

The cathode 21 includes, for example, a gas diffusion layer 21A and a cathode catalyst layer 21B. A part of the cathode catalyst layer may enter the gas diffusion layer. A porous layer denser than the gas diffusion layer may be arranged between the gas diffusion layer and the cathode catalyst layer.

As a cathode catalyst for forming the cathode catalyst layer, a known catalyst that promotes reduction of carbon dioxide can be used. Specific examples of cathode catalysts include metals such as gold, silver, copper, platinum, palladium, nickel, cobalt, iron, manganese, titanium, cadmium, zinc, indium, gallium, lead, and tin, their alloys and intermetallic compounds, and metal complexes such as ruthenium complexes and rhenium complexes. Among these, copper and silver are preferable, and copper is more preferable in order to promote reduction of carbon dioxide. Cathode catalysts may be used alone or two or more thereof may be used in combination.

As the cathode catalyst, a supported catalyst in which metal particles are supported on a carbon material (carbon particles, carbon nanotubes, graphene, etc.) may be used.

The gas diffusion layer in the cathode 21 is not particularly limited, and for example, carbon paper and carbon cloth may be exemplified.

The method of producing the cathode 21 is not particularly limited, and for example, a method of applying a solution composition containing a cathode catalyst to the surface of the gas diffusion layer opposite to the cathode-side solution flow path forming member 24 and drying it may be exemplified.

The reduction reaction of CO₂ is thought to occur near the boundary between the gas diffusion layer and the cathode catalyst layer (or cathode catalyst) in the cathode 21.

The anode section 30 includes an anode 31 and an anode-side solution flow path forming member (anode-side separator) 34 that forms an anode-side solution flow path 32 between itself and the anode 31.

The anode 31 is an electrode for oxidizing hydroxide ions to produce oxygen. The anode 31 includes, for example, a gas diffusion layer and a cathode catalyst layer.

An anode catalyst for forming an anode catalyst layer is not particularly limited, and a known anode catalyst can be used. Specifically, for example, metals such as platinum, palladium, and nickel, their alloys and intermetallic compounds, metal oxides such as manganese oxide, iridium oxide, nickel oxide, cobalt oxide, iron oxide, tin oxide, indium oxide, ruthenium oxide, lithium oxide, and lanthanum oxide, and metal complexes such as ruthenium complexes and rhenium complexes may be exemplified. Anode catalysts may be used alone or two or more thereof may be used in combination.

As the gas diffusion layer in the anode 31, for example, carbon paper and carbon cloth may be exemplified. In addition, as the gas diffusion layer, a porous component such as a mesh material, a punching material, a porous material, and a metal fiber sintered component may be used. As the material of the porous component, for example, metals such as titanium, nickel, and iron, and their alloys (for example, SUS) may be exemplified.

As the diaphragm 40, a known separator that can move ions between the anode section and the cathode section and can separate the anode section and the cathode section can be used. Typical examples include ion exchange membranes such as an anion exchange membrane, a cation exchange membrane, a proton exchange membrane, and a bipolar membrane. In addition, in addition to ion exchange membranes, separators such as various porous membranes can be applied as long as they are made of materials that can move ions between the anode section and the cathode section.

The thickness of the diaphragm 40 is preferably 0.03 to 0.5 mm and more preferably 0.05 to 0.1 mm. If the thickness of the diaphragm 40 is equal to or more than the lower limit value of the above range, mechanical strength and durability can be obtained. If the thickness of the diaphragm 40 is equal to or less than the upper limit value of the above range, ion movement resistance is kept low.

FIGS. 3A and 3B are schematic plan views showing a conventional typical structure example of a cathode-side solution flow path forming member or an anode-side solution flow path forming member. Hereinafter, mainly, a case in which FIGS. 3A and 3B are a cathode-side solution flow path forming member will be exemplified. As the flow path structure itself of the cathode-side solution flow path forming member and the anode-side solution flow path forming member included in the carbon dioxide electrolysis cell according to the embodiment, a known flow path structure can be used, and FIGS. 3A and 3B are examples thereof.

In a cathode-side solution flow path forming member 200 shown in FIG. 3A, a cathode-side solution supply hole 210A and an anode-side solution supply hole 230A are provided at one end 200A, and on the other hand, a cathode-side solution discharge hole 210B and an anode-side solution discharge hole 230B are provided at the other end 200B. In addition, a cathode-side solution flow path 220 is provided between the one end 200A and the other end 200B.

In the cathode-side solution flow path forming member 200, one cathode-side solution supply hole and one cathode-side solution discharge hole (one pair), and one anode-side solution supply hole and one anode-side solution discharge hole (one pair) are provided.

In the cathode-side solution flow path forming member 200, a plurality of protrusion parts 201 are formed on one surface of the cathode-side solution flow path forming member 200, and the cathode-side solution flow path 220 is formed between the protrusion parts 201. The protrusion part 201 is formed, for example, by embossing.

Similarly, in the anode-side solution flow path forming member, a cathode-side solution supply hole and an anode-side solution supply hole are provided at one end, and on the other hand, a cathode-side solution discharge hole and an anode-side solution discharge hole are provided at the other end. In addition, the anode-side solution flow path is provided between one end and the other end.

The cathode-side solution supplied from the manifold (described below) is supplied to the cathode-side solution flow path 220 from the cathode-side solution supply hole 210A provided at the one end 200A of the cathode-side solution flow path forming member 200. The cathode-side solution flowing through the cathode-side solution flow path 220 contains a carbon compound produced according to a reduction reaction of carbon dioxide near the boundary between the gas diffusion layer and the cathode catalyst layer and is recovered into the manifold from the cathode-side solution discharge hole 210B.

Similarly, the anode-side solution supplied from the manifold (described below) is supplied to the anode-side solution flow path from the anode-side solution supply hole provided at one end of the anode-side solution flow path forming member. The anode-side solution flowing through the anode-side solution flow path contains a product produced according to an oxidation reaction and is recovered into the manifold from the anode-side solution discharge hole.

In a carbon dioxide electrolysis device formed by laminating a plurality of carbon dioxide electrolysis cells, the manifold is configured to supply a cathode-side solution or an anode-side solution to these plurality of carbon dioxide electrolysis cells and recovery the cathode-side solution or the anode-side solution from the plurality of carbon dioxide electrolysis cells.

In a cathode-side solution flow path forming member 300 shown in FIG. 3B, a cathode-side solution supply hole 310A and an anode-side solution supply hole 330A are provided at one end 300A, and on the other hand, a cathode-side solution discharge hole 310B and an anode-side solution discharge hole 330B are provided at the other end 300B. In addition, a cathode-side solution flow path 320 is provided between the one end 300A and the other end 300B.

In the cathode-side solution flow path forming member 300, similar to the cathode-side solution flow path forming member 200, one cathode-side solution supply hole and one cathode-side solution discharge hole (one pair), and one anode-side solution supply hole and one anode-side solution discharge hole (one pair) are provided.

In the cathode-side solution flow path forming member 300, a plurality of groove parts 301 extending substantially linearly in a direction in which the one end 300A and the other end 300B are connected are formed on one surface of the cathode-side solution flow path forming member 300, and these plurality of groove parts 301 constitute the cathode-side solution flow path 320. In the cathode-side solution flow path forming member 300, folding partition members 305a and 305b are spaced apart from each other and provided in a zigzag, and the cathode-side solution flow path 320 is a meandering flow path that is folded back by one and a half round.

In the cathode-side solution flow path forming member 300, similar to the cathode-side solution flow path forming member 200, the cathode-side solution supplied from the manifold is supplied to the cathode-side solution flow path 320 from the cathode-side solution supply hole 310A provided at the one end 300A of the cathode-side solution flow path forming member 300. The cathode-side solution flowing through the cathode-side solution flow path 320 contains carbon compound produced according to a reduction reaction of carbon dioxide near the boundary between the gas diffusion layer and the cathode catalyst layer and is recovered into the manifold from the cathode-side solution discharge hole 310B.

The same applies to the anode-side solution.

FIG. 4 is a schematic plan view of the cathode-side solution flow path forming member included in the carbon dioxide electrolysis cell according to the embodiment. The example shown in FIG. 4 is a case in which a flow path is formed between protrusion parts (refer to FIG. 3A).

The cathode-side solution flow path forming member 24 shown in FIG. 4 has a rectangular shape in a plan view in the direction (Z direction) in which the cathode section, the diaphragm and the anode section are stacked. When the direction in which the cathode-side solution flows is set as a vertical direction, and the direction perpendicular thereto is set as a horizontal direction, the cathode-side solution flow path forming member 24 has a horizontally elongated shape in a plan view.

Here, the rectangular or horizontally elongated shape is a shape in which the ratio (Lx/Ly) of the length Lx of the cathode-side solution flow path forming member 24 in the horizontal direction (X direction) to the length Ly in the vertical direction (Y direction) is, for example, 1.1 to 50, although it is not particularly limited.

In this case, when the length Ly of the cathode-side solution flow path forming member 24 is, for example, 100 mm to 2,000 mm, the length Lx is 110 mm to 100,000 mm.

The conventional typical cathode-side solution flow path forming members 200 and 300 shown in FIGS. 3A and 3B each had one cathode-side solution supply hole and one cathode-side solution discharge hole, and one anode-side solution supply hole and one anode-side solution discharge hole (one pair each). In this case, for example, in the cathode-side solution flow path forming member 200 shown in FIG. 3A, the cathode-side solution does not flow sufficiently in the area (an area surrounded by a dotted line circle; a dead zone in the cross flow) in the direction intersecting the direction in which the cathode-side solution supply hole and the cathode-side solution discharge hole are connected (direction in which the cathode-side solution flows) compared to the area in the direction in which the cathode-side solution flows, and there is a problem with the uniformity of the flow of an electrolyte as a raw material. Here, due to the pressure loss specific to an electrolysis cell, the area cannot be enlarged in the direction in which the electrolyte flows, and thus it has to be horizontally elongated, but with such a horizontally elongated cathode-side solution flow path forming member, the problem of the uniformity of the flow of the electrolyte becomes more significant.

In addition, in the cathode-side solution flow path forming member 300 shown in FIG. 3B, since the electrolyte as a raw material flows in a meandering manner, the upper limit of the flow rate of the electrolyte that can flow is reduced due to the pressure loss specific to an electrolysis cell, and there is a concern that discharge of the produced gas may be hindered.

There is a concern that the anode-side solution flow path forming member has similar problems.

The above two problems are solved by providing a plurality of cathode-side solution supply holes and cathode-side solution discharge holes, and a plurality of anode-side solution supply holes and anode-side solution discharge holes, which are arranged alternately in the horizontal direction, using the horizontally elongated cathode-side solution flow path forming member in the carbon dioxide electrolysis cell of the present embodiment. That is, if it is configured such that, when the size is increased in the horizontal direction, the inlet and the outlet of the electrolyte also increase in size accordingly, and the cross flow is minimized as much as possible, uniform flowing of the electrolyte over the entire electrode is secured even if the size is increased.

In the cathode-side solution flow path forming member 24 shown in FIG. 4, at one end 20A, which is one short side of the pair of opposing rectangular short sides of the cathode-side solution flow path forming member, a plurality of cathode-side solution supply holes 25A-1, 25A-2, 25A-3, and 25A-4 for supplying a cathode-side solution to the cathode-side solution flow path are provided, and at the other end 20B, which is the other short side of the pair of short sides, a plurality of cathode-side solution discharge holes 25B-1, 25B-2, 25B-3, and 25B-4 for discharging a cathode-side solution are provided. In addition, at the one end 20A, a plurality of anode-side solution supply holes 27A-1, 27A-2, 27A-3, and 27A-4 for supplying an anode-side solution to the anode-side solution flow path are provided, and at the other end 20B, a plurality of anode-side solution discharge holes 27B-1, 27B-2, 27B-3, and 27B-4 for discharging a cathode-side solution are provided.

In a plan view from the Z direction, the plurality of cathode-side solution supply holes 25A-1, 25A-2, 25A-3, and 25A-4 and the plurality of anode-side solution supply holes 27A-1, 27A-2, 27A-3, and 27A-4 are arranged alternately, and the plurality of cathode-side solution discharge holes 25B-1, 25B-2, 25B-3, and 25B-4 and the plurality of anode-side solution discharge holes 27B-1, 27B-2, 27B-3, and 27B-4 are arranged alternately.

In addition, the order in which the plurality of cathode-side solution supply holes 25A-1, 25A-2, 25A-3, and 25A-4 and the plurality of anode-side solution supply holes 27A-1, 27A-2, 27A-3, and 27A-4 are arranged alternately is opposite to the order in which the plurality of cathode-side solution discharge holes 25B-1, 25B-2, 25B-3, and 25B-4 and the plurality of anode-side solution discharge holes 27B-1, 27B-2, 27B-3, and 27B-4 are arranged alternately. In addition, the plurality of cathode-side solution supply holes 25A-1, 25A-2, 25A-3, and 25A-4 and the plurality of cathode-side solution discharge holes 25B-1, 25B-2, 25B-3, and 25B-4 are arranged at mutually shifted positions on the one end 20A and the other end 20B, and this arrangement realizes cross flow.

The cathode-side solution supplied from the manifold (described below) is supplied to the cathode-side solution flow path 22 from the plurality of cathode-side solution supply holes 25A-1, 25A-2, 25A-3, and 25A-4 provided at the one end 20A of the cathode-side solution flow path forming member 24. The cathode-side solution flowing through the cathode-side solution flow path 22 contains a carbon compound produced according to a reduction reaction of carbon dioxide near the boundary between the gas diffusion layer and the cathode catalyst layer and is recovered into the manifold from the plurality of cathode-side solution discharge holes 25B-1, 25B-2, 25B-3, and 25B-4.

The cathode-side solution flow path forming member 24 has a configuration including four cathode-side solution supply holes and four cathode-side solution discharge holes, but the number four is an example.

The numbers of cathode-side solution supply holes and cathode-side solution discharge holes are not particularly limited, but they depend on the size of the electrolysis cell, the distance between an adjacent cathode-side solution supply hole and an anode-side solution supply hole (similarly, the distance between an adjacent cathode-side solution discharge hole and an anode-side solution discharge hole), and the sizes of supply holes and discharge holes.

For example, regarding the size of the electrolysis cell, if the length Lx is 2,000 mm, when the length of the supply hole and the discharge hole in the Lx direction is 40 mm to 400 mm, the distance between adjacent supply holes and the distance between adjacent discharge holes may be 10 mm to 100 mm. In this case, the number of supply holes or the number of discharge holes (density) is 0.001 to 0.01 holes/mm.

In the cathode-side solution flow path forming member 24, the flow path 22 is formed between protrusion parts 22a. Protrusion parts and groove parts may be formed in a connecting area 28 connecting the cathode-side solution supply holes 25A-1, 25A-2, 25A-3, and 25A-4 and the flow path 22 and in a connecting area 29 connecting the flow path 22 and the cathode-side solution discharge holes 25B-1, 25B-2, 25B-3, and 25B-4.

FIG. 5 is a schematic plan view of the anode-side solution flow path forming member included in the carbon dioxide electrolysis cell according to the embodiment. The example shown in FIG. 5 is a case in which a flow path is formed between protrusion parts (refer to FIG. 3A), similar to the cathode-side solution flow path forming member 24. The anode-side solution flow path forming member is also produced based on the technical idea common to the cathode-side solution flow path forming member. Description of common points may be omitted.

Similar to the cathode-side solution flow path forming member 24, the anode-side solution flow path forming member 34 shown in FIG. 5 has a rectangular shape in a plan view in the direction (Z direction) in which the cathode section, the diaphragm and the anode section are stacked. When the direction in which the anode-side solution flows is set as a vertical direction, and the direction perpendicular thereto is set as a horizontal direction, the anode-side solution flow path forming member 34 has a horizontally elongated shape in a plan view.

In the anode-side solution flow path forming member 34 shown in FIG. 5, at one end 30A, which is one short side of the pair of opposing rectangular short sides of the anode-side solution flow path forming member, a plurality of anode-side solution supply holes 37A-1, 37A-3, 37A-3, and 37A-4 for supplying an anode-side solution to the anode-side solution flow path are provided, and at the other end 30B, which is the other short side of the pair of short sides, a plurality of anode-side solution discharge holes 37B-1, 37B-2, 37B-3, and 37B-4 for discharging an anode-side solution are provided. At one end 30A, a plurality of cathode-side solution supply holes 35A-1, 35A-2, 35A-3, and 35A-4 for supplying a cathode-side solution to the cathode-side solution flow path are provided, and at the other end 30B, a plurality of cathode-side solution discharge holes 35B-1, 35B-2, 35B-3, and 35B-4 for discharging a cathode-side solution are provided.

In a plan view from the Z direction, the plurality of anode-side solution supply holes 37A-1, 37A-3, 37A-3, and 37A-4 and the plurality of cathode-side solution supply holes 35A-1, 35A-2, 35A-3, and 35A-4 are arranged alternately, and the plurality of anode-side solution discharge holes 37B-1, 37B-2, 37B-3, and 37B-4 and the plurality of cathode-side solution discharge holes 35B-1, 35B-2, 35B-3, and 35B-4 are arranged alternately.

In addition, the order in which the plurality of anode-side solution supply holes 37A-1, 37A-3, 37A-3, and 37A-4 and the plurality of cathode-side solution supply holes 35A-1, 35A-2, 35A-3, and 35A-4 are arranged alternately is opposite to the order in which the plurality of anode-side solution discharge holes 37B-1, 37B-2, 37B-3, and 37B-4 and the plurality of cathode-side solution discharge holes 35B-1, 35B-2, 35B-3, and 35B-4 are arranged alternately. In addition, the plurality of anode-side solution supply holes 37A-1, 37A-3, 37A-3, and 37A-4 and the plurality of anode-side solution discharge holes 37B-1, 37B-2, 37B-3, and 37B-4 are arranged at mutually shifted positions on the one end 20A and the other end 20B, and this arrangement realizes cross flow.

The anode-side solution supplied from the manifold (described below) is supplied to the anode-side solution flow path 32 from the plurality of anode-side solution supply holes 37A-1, 37A-3, 37A-3, and 37A-4 provided at one end 30A of the anode-side solution flow path forming member 34. The anode-side solution flowing through the anode-side solution flow path 32 contains a product produced according to an oxidation reaction and is recovered into the manifold from the plurality of anode-side solution discharge holes 37B-1, 37B-2, 37B-3, and 37B-4.

The anode-side solution flow path forming member 34 has a configuration including four anode-side solution supply holes and four anode-side solution discharge holes, but the number four is an example.

In the anode-side solution flow path forming member 34, the flow path 32 is formed between protrusion parts 32a. Protrusion parts and groove parts may be formed in a connecting area 38 connecting the anode-side solution supply holes 37A-1, 37A-3, 37A-3, and 37A-4 and the flow path 32 and in a connecting area 39 connecting the anode-side solution discharge holes 37B-1, 37B-2, 37B-3, and 37B-4 and a flow path 39.

FIG. 6 is a schematic cross-sectional view of a carbon dioxide electrolysis device 100 including a single carbon dioxide electrolysis cell 10.

The carbon dioxide electrolysis device 100 shown FIG. 6 includes a carbon dioxide electrolysis cell 10, a first power supplying body 51, a second power supplying body 52, and a power source device 60, and is interposed between a pair of support plates (not shown), and additionally fastened with a bolt or the like.

Examples of materials of the first power supplying body 51 and the second power supplying body 52 include metals such as copper, gold, titanium, and SUS, and carbon. As the first power supplying body 51 and the second power supplying body 52, those obtained by performing a plating treatment such as gold plating on the surface of a copper substrate may be used.

The cathode-side solution flow path forming member 24 and the anode-side solution flow path forming member 34 are conductors, and a voltage is applied between the cathode 21 and the anode 31 from the power source device 60.

The power source 60 is not limited to a general grid power source, a battery and the like, but may be a power source that supplies power generated by renewable energy from solar cells, wind power generation, geothermal power generation or the like.

FIG. 7 is a schematic cross-sectional view of a carbon dioxide electrolysis device 110 including a plurality of carbon dioxide electrolysis cells 10. FIG. 8A is a perspective view in which a plurality of carbon dioxide electrolysis cells 10 are arranged apart from each other in order to facilitate understanding of the configuration of the carbon dioxide electrolysis device 110 shown in FIG. 7, and FIG. 8B is a perspective view showing arrangement of a manifold (not shown in FIG. 7) included in the carbon dioxide electrolysis device 110 shown in FIG. 7.

The carbon dioxide electrolysis device 110 shown in FIG. 7 includes a plurality (N) of carbon dioxide electrolysis cells 10, a first power supplying body 151 and a second power supplying body 152 arranged to surround the plurality of carbon dioxide electrolysis cells 10, and the power source device 60.

A carbon dioxide electrolysis device 200 shown in FIG. 7 further includes support plates 81 and 82 on the outside of the first power supplying body 151 and the second power supplying body 152 with insulation plates 71 and 72 therebetween, which are fastened with a bolt (not shown) or the like.

In the example shown in FIG. 7, the cathode-side solution flow path forming member 24 and the anode-side solution flow path forming member 34 of the adjacent carbon dioxide electrolysis cells 10 are the front side and the back side of a common member (separator).

The N carbon dioxide electrolysis cells 10 are the carbon dioxide electrolysis cell 10-1, the carbon dioxide electrolysis cell 10-2, . . . the carbon dioxide electrolysis cell 10-(N−1), and the carbon dioxide electrolysis cell 10-N in order from the side of the first power supplying body 151. The anode-side solution flow path forming member 34 included in the carbon dioxide electrolysis cell 10-1 and the cathode-side solution flow path forming member 24 included in the carbon dioxide electrolysis cell 10-2 form a solution flow path on the front side and the back side of a common member.

The plurality of carbon dioxide electrolysis cells 10 shown in FIG. 8A are composed of six electrolysis cells 10a, 10b, 10c, 10d, 10e, and 10f.

As shown in FIG. 8B, separate manifolds are provided for solution supply and for solution recovery. The solution supply manifold includes four cathode-side solution supply manifolds 55A-1, 55A-2, 55A-3, and 55A-4 and four anode-side solution supply manifolds 57A-1, 57A-2, 57A-3, and 57A-4. In addition, the solution recovery manifold includes four cathode-side solution supply manifolds 55B-1, 55B-2, 55B-3, and 55B-4 and four anode-side solution supply manifolds 57B-1, 57B-2, 57B-3, and 57B-4.

A manifold is provided for each of the supply holes and discharge holes arranged at the same position in each electrolysis cell.

The cathode-side solution supply manifold 55A-1 is configured to distribute a cathode-side solution to a cathode-side solution supply hole of the electrolysis cell 10b, a cathode-side solution supply hole of the electrolysis cell 10c, a cathode-side solution supply hole of the electrolysis cell 10d, a cathode-side solution supply hole of the electrolysis cell 10e, and a cathode-side solution supply hole of the electrolysis cell 10f located at the same position of a cathode-side solution supply hole 25A-1a of the electrolysis cell 10a.

The cathode-side solution supply manifold 55A-2 is configured to distribute a cathode-side solution to a cathode-side solution supply hole of the electrolysis cell 10b, a cathode-side solution supply hole of the electrolysis cell 10c, a cathode-side solution supply hole of the electrolysis cell 10d, a cathode-side solution supply hole of the electrolysis cell 10e, and a cathode-side solution supply hole of the electrolysis cell 10f located at the same position of a cathode-side solution supply hole 25A-2a of the electrolysis cell 10a.

The cathode-side solution supply manifold 55A-3 is configured to distribute a cathode-side solution to a cathode-side solution supply hole of the electrolysis cell 10b, a cathode-side solution supply hole of the electrolysis cell 10c, a cathode-side solution supply hole of the electrolysis cell 10d, a cathode-side solution supply hole of the electrolysis cell 10e, and a cathode-side solution supply hole of the electrolysis cell 10f located at the same position of a cathode-side solution supply hole 25A-3a of the electrolysis cell 10a.

The cathode-side solution supply manifold 55A-4 is configured to distribute a cathode-side solution to a cathode-side solution supply hole of the electrolysis cell 10b, a cathode-side solution supply hole of the electrolysis cell 10c, a cathode-side solution supply hole of the electrolysis cell 10d, a cathode-side solution supply hole of the electrolysis cell 10e, and a cathode-side solution supply hole of the electrolysis cell 10f located at the same position of a cathode-side solution supply hole 25A-4a of the electrolysis cell 10a.

The anode-side solution supply manifold 57A-1 is configured to distribute an anode-side solution to an anode-side solution supply hole of the electrolysis cell 10b, an anode-side solution supply hole of the electrolysis cell 10c, an anode-side solution supply hole of the electrolysis cell 10d, an anode-side solution supply hole of the electrolysis cell 10e, and an anode-side solution supply hole of the electrolysis cell 10f located at the same position of an anode-side solution supply hole 27A-1a of the electrolysis cell 10a.

The anode-side solution supply manifold 57A-2 is configured to distribute an anode-side solution to an anode-side solution supply hole of the electrolysis cell 10b, an anode-side solution supply hole of the electrolysis cell 10c, an anode-side solution supply hole of the electrolysis cell 10d, an anode-side solution supply hole of the electrolysis cell 10e, an anode-side solution supply hole of the electrolysis cell 10f located at the same position of an anode-side solution supply hole 27A-2a of the electrolysis cell 10a.

The anode-side solution supply manifold 57A-3 is configured to distribute an anode-side solution to an anode-side solution supply hole of the electrolysis cell 10b, an anode-side solution supply hole of the electrolysis cell 10c, an anode-side solution supply hole of the electrolysis cell 10d, an anode-side solution supply hole of the electrolysis cell 10e, and an anode-side solution supply hole of the electrolysis cell 10f located at the same position of an anode-side solution supply hole 27A-3a of the electrolysis cell 10a.

The anode-side solution supply manifold 57A-4 is configured to distribute an anode-side solution to an anode-side solution supply hole 27A-4b of the electrolysis cell 10b, an anode-side solution supply hole 27A-4c of the electrolysis cell 10c, an anode-side solution supply hole 27A-4d of the electrolysis cell 10d, an anode-side solution supply hole 27A-4e of the electrolysis cell 10e, and an anode-side solution supply hole 27A-4f of the electrolysis cell 10f located at the same position of an anode-side solution supply hole 27A-4a of the electrolysis cell 10a.

The cathode-side solution discharge manifold 55B-1 is configured to distribute a cathode-side solution to a cathode-side solution discharge hole 25B-1b of the electrolysis cell 10b, a cathode-side solution discharge hole 25B-1c of the electrolysis cell 10c, a cathode-side solution discharge hole 25B-1d of the electrolysis cell 10d, a cathode-side solution discharge hole 25B-1e of the electrolysis cell 10e, and a cathode-side solution discharge hole 25B-1f of the electrolysis cell 10f located at the same position of a cathode-side solution discharge hole 25B-1a of the electrolysis cell 10a.

The cathode-side solution discharge manifold 55B-2 is configured to distribute a cathode-side solution to a cathode-side solution discharge hole of the electrolysis cell 10b, a cathode-side solution discharge hole of the electrolysis cell 10c, a cathode-side solution discharge hole of the electrolysis cell 10d, a cathode-side solution discharge hole of the electrolysis cell 10e, and a cathode-side solution discharge hole 25B-2f of the electrolysis cell 10f located at the same position of a cathode-side solution discharge hole of the electrolysis cell 10a.

The cathode-side solution discharge manifold 55B-3 is configured to distribute a cathode-side solution to a cathode-side solution discharge hole of the electrolysis cell 10b, a cathode-side solution discharge hole of the electrolysis cell 10c, a cathode-side solution discharge hole of the electrolysis cell 10d, a cathode-side solution discharge hole of the electrolysis cell 10e, and a cathode-side solution discharge hole 25B-3f of the electrolysis cell 10f located at the same position of a cathode-side solution discharge hole of the electrolysis cell 10a.

The cathode-side solution discharge manifold 55B-4 is configured to distribute a cathode-side solution to a cathode-side solution discharge hole of the electrolysis cell 10b, a cathode-side solution discharge hole of the electrolysis cell 10c, a cathode-side solution discharge hole of the electrolysis cell 10d, a cathode-side solution discharge hole of the electrolysis cell 10e, and a cathode-side solution discharge hole 25B-4f of the electrolysis cell 10f located at the same position of a cathode-side solution discharge hole 25B-4a of the electrolysis cell 10a.

The anode-side solution discharge manifold 57B-1 is configured to distribute an anode-side solution to an anode-side solution discharge hole of the electrolysis cell 10b, an anode-side solution discharge hole of the electrolysis cell 10c, an anode-side solution discharge hole of the electrolysis cell 10d, an anode-side solution discharge hole of the electrolysis cell 10e, and an anode-side solution discharge hole 27B-1f of the electrolysis cell 10f located at the same position of an anode-side solution discharge hole of the electrolysis cell 10a.

The anode-side solution discharge manifold 57B-2 is configured to distribute an anode-side solution to an anode-side solution discharge hole of the electrolysis cell 10b, an anode-side solution discharge hole of the electrolysis cell 10c, an anode-side solution discharge hole of the electrolysis cell 10d, an anode-side solution discharge hole of the electrolysis cell 10e, and an anode-side solution discharge hole 27B-2f of the electrolysis cell 10f located at the same position of an anode-side solution discharge hole of the electrolysis cell 10a.

The anode-side solution discharge manifold 57B-3 is configured to distribute an anode-side solution to an anode-side solution discharge hole of the electrolysis cell 10b, an anode-side solution discharge hole of the electrolysis cell 10c, an anode-side solution discharge hole of the electrolysis cell 10d, an anode-side solution discharge hole of the electrolysis cell 10e, and an anode-side solution discharge hole 27B-3f of the electrolysis cell 10f located at the same position of an anode-side solution discharge hole of the electrolysis cell 10a.

The anode-side solution discharge manifold 57B-4 is configured to distribute an anode-side solution to an anode-side solution discharge hole 27B-4b of the electrolysis cell 10b, an anode-side solution discharge hole 27B-4c of the electrolysis cell 10c, an anode-side solution discharge hole 27B-4d of the electrolysis cell 10d, an anode-side solution discharge hole 27B-4e of the electrolysis cell 10e, and an anode-side solution discharge hole 27B-4f of the electrolysis cell 10f located at the same position of an anode-side solution discharge hole of the electrolysis cell 10a.

As shown in FIG. 8B, four cathode-side solution supply manifolds 55A-1, 55A-2, 55A-3, and 55A-4, and four anode-side solution supply manifolds 57A-1, 57A-2, 57A-3, and 57A-4 are arranged alternately to correspond to alternate arrangement of the cathode-side solution supply holes and anode-side solution supply holes of the electrolysis cells.

In addition, as shown in FIG. 8B, four cathode-side solution supply manifolds 55B-1, 55B-2, 55B-3, and 55B-4, and four anode-side solution supply manifolds 57B-1, 57B-2, 57B-3, and 57B-4 are arranged alternately to correspond to alternate arrangement of the cathode-side solution discharge holes and anode-side solution discharge holes of the electrolysis cells.

They are arranged alternately to correspond to respective positions of the cathode-side solution supply holes, cathode-side solution discharge holes, anode-side solution supply holes and anode-side solution discharge holes of the electrolysis cells.

In addition, the order in which four cathode-side solution supply manifolds 55A-1, 55A-2, 55A-3, and 55A-4, and four anode-side solution supply manifolds 57A-1, 57A-2, 57A-3, and 57A-4 are arranged alternately is opposite to the order in which four cathode-side solution supply manifolds 55B-1, 55B-2, 55B-3, and 55B-4, and four anode-side solution supply manifolds 57B-1, 57B-2, 57B-3, and 57B-4 are arranged alternately. This arrangement realizes cross flow.

While preferred embodiments of the invention have been described and illustrated above, it should be understood that these are exemplary of the invention and are not to be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit or scope of the present invention. Accordingly, the invention is not to be considered as being limited by the foregoing description, and is only limited by the scope of the appended claims.

EXPLANATION OF REFERENCES

• • 10 Carbon dioxide electrolysis cell
  • 20 Cathode section
  • 21 Cathode
  • 22 Cathode-side solution flow path
  • 24 Cathode-side solution flow path forming member
  • 30 Anode section
  • 31 Anode
  • 32 Anode-side solution flow path
  • 34 Anode-side solution flow path forming member
  • 40 Diaphragm
  • 100, 110 Carbon dioxide electrolysis device