Electrolysis cell and electrolysis device

Abstract

To provide an electrolysis cell and an electrolysis device whose electrolysis performance can be improved.SOLUTION: The electrolysis cell comprises: a first separator; a second separator; an anion exchange membrane disposed between the first separator and the second separator; a cathode disposed between the first separator and the anion exchange membrane; and an anode disposed between the second separator and the anion exchange membrane. The first separator has a flow path for supplying the cathode with an electrolytic solution, and at least a part of the electrolytic solution supplied from the flow path is consumed to generate hydrogen and a hydroxide ion in the cathode. The second separator does not have a flow path for supplying the anode with the electrolytic solution, and oxygen and water are generated from the hydroxide ion passing through the anion exchange membrane from the cathode, in a state where the electrolytic solution is not supplied in the anode.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to electrolysis cells and apparatus. [Background technology]

[0002] Patent Document 1 discloses a PEM (Polymer Electrolyte Membrane) type electrolysis device in which an electric current flows between both sides of an electrolytic membrane including a solid polymer membrane having a catalyst layer on its surface. This electrolysis device produces oxygen by supplying water to the negative electrode (cathode) side of the electrolytic membrane while controlling the pressure difference between both sides of the electrolytic membrane.

[0003] In a PEM electrolysis device, when a voltage is applied between the anode and cathode, the following chemical reaction occurs on the anode side, consuming water and producing oxygen: 2H2O→4H + +4e - +O2 In addition, in the cathode chamber, the following chemical reaction occurs, producing hydrogen from the electrolyte: 4H + +4e - →2H2 [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6332792 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the PEM-type water electrolysis device described in Patent Document 1, water is consumed on the anode side, but water is supplied only to the cathode side. Therefore, the water supplied to the cathode side moves to the anode side through the electrolytic membrane and is used for a chemical reaction, and the protons (H +) moves back to the cathode side to generate hydrogen. During this process, resistance exists in the process where water or protons pass through the electrolytic membrane. For this reason, with the above configuration, it is difficult to improve the electrolytic performance.

[0006] The present disclosure has been made to solve the above-mentioned problems, and has an object to provide an electrolysis cell and an electrolysis device that can improve electrolysis performance. [Means for solving the problem]

[0007] In order to solve the above problems, an electrolytic cell according to the present disclosure includes a first separator, a second separator, an anion exchange membrane disposed between the first separator and the second separator, a cathode disposed between the first separator and the anion exchange membrane, and an anode disposed between the second separator and the anion exchange membrane, wherein the first separator has a flow path for supplying an electrolytic solution to the cathode, and at least a portion of the electrolytic solution supplied from the flow path is consumed at the cathode to generate hydrogen and hydroxide ions, and the second separator does not have a flow path for supplying the electrolytic solution to the anode, and at the anode, oxygen and water are generated by the hydroxide ions that have passed through the anion exchange membrane from the cathode in a state in which the electrolytic solution is not supplied. The second separator has a gas outlet through which the oxygen is mainly discharged and a liquid outlet through which the water is mainly discharged, and the gas outlet and the liquid outlet are provided separately on the second separator. The electrolysis cell according to the present disclosure includes a first separator, a second separator, an anion exchange membrane disposed between the first separator and the second separator, a cathode disposed between the first separator and the anion exchange membrane, and an anode disposed between the second separator and the anion exchange membrane, the first separator having a flow path for supplying an electrolytic solution to the cathode, at least a portion of the electrolytic solution supplied from the flow path is consumed in the cathode to generate hydrogen and hydroxide ions, and the second separator having a flow path for supplying hydrogen and hydroxide ions to the cathode. The electrolytic cell has no flow path for supplying the electrolytic solution to the anode, and at the anode, oxygen and water are generated by the hydroxide ions that have passed through the anion exchange membrane from the cathode in a state in which the electrolytic solution is not supplied, and an anode chamber is defined between the second separator and the anion exchange membrane, and the second separator has an outlet through which the oxygen and the water are discharged, and the outlet is formed such that an upper end of the outlet is located above the water level of the water accumulated in the anode chamber in a steady operation state of the electrolytic cell. The electrolytic cell according to the present disclosure comprises a first separator, a second separator, an anion exchange membrane disposed between the first separator and the second separator, a cathode disposed between the first separator and the anion exchange membrane, and an anode disposed between the second separator and the anion exchange membrane, wherein the first separator has a flow path for supplying an electrolytic solution to the cathode, at least a part of the electrolytic solution supplied from the flow path is consumed at the cathode to produce hydrogen and hydroxide ions, the second separator does not have a flow path for supplying the electrolytic solution to the anode, and at the anode, oxygen and water are produced by the hydroxide ions that have passed through the anion exchange membrane from the cathode in a state in which the electrolytic solution is not supplied, an anode chamber is defined between the second separator and the anion exchange membrane, and the second separator has an outlet from which the oxygen and the water are discharged, the outlet being provided at the vertical center of the anode chamber or below the vertical center. The electrolytic cell according to the present disclosure includes a first separator, a second separator, an anion exchange membrane disposed between the first separator and the second separator, a cathode disposed between the first separator and the anion exchange membrane, and an anode disposed between the second separator and the anion exchange membrane, the first separator having a flow path for supplying an electrolytic solution to the cathode, in which at least a portion of the electrolytic solution supplied from the flow path is consumed to produce hydrogen and hydroxide ions, and the second separator having a flow path for supplying the electrolytic solution to the anode. First, in the anode, oxygen and water are generated by the hydroxide ions that have passed through the anion exchange membrane from the cathode in a state in which the electrolyte is not supplied, the cathode is disposed between the first separator and the anion exchange membrane and includes a cathode power supply which is a mesh structure, a porous body, or a fiber, and the anode is disposed between the second separator and the anion exchange membrane and includes an anode power supply which is a mesh structure, a porous body, or a fiber, and the average size of the multiple holes in the anode power supply is larger than the average size of the multiple holes in the cathode power supply. The electrolytic cell according to the present disclosure includes a first separator, a second separator, an anion exchange membrane disposed between the first separator and the second separator, a cathode disposed between the first separator and the anion exchange membrane, and an anode disposed between the second separator and the anion exchange membrane, wherein the first separator has a flow path for supplying an electrolytic solution to the cathode, and at least a portion of the electrolytic solution supplied from the flow path is consumed in the cathode to produce hydrogen and hydroxide ions, and the second separator has a flow path for supplying the electrolytic solution to the anode. The anode does not have a flow path for supplying oxygen and water to the cathode, and in a state in which the electrolyte is not supplied, oxygen and water are generated by the hydroxide ions that have passed through the anion exchange membrane from the cathode, the cathode is disposed between the first separator and the anion exchange membrane, and includes a cathode current collector which is a mesh structure, a porous body, or a fiber, and the anode is disposed between the second separator and the anion exchange membrane, and includes an anode current collector which is a mesh structure, a porous body, or a fiber, and the porosity of the anode current collector is greater than the porosity of the cathode current collector. The electrolytic cell according to the present disclosure includes a first separator, a second separator, an anion exchange membrane disposed between the first separator and the second separator, a cathode disposed between the first separator and the anion exchange membrane, and an anode disposed between the second separator and the anion exchange membrane, wherein the first separator has a flow path for supplying an electrolytic solution to the cathode, and at least a portion of the electrolytic solution supplied from the flow path is consumed in the cathode to produce hydrogen and hydroxide ions, and the second separator does not have a flow path for supplying the electrolytic solution to the anode, and In the anode, oxygen and water are generated by the hydroxide ions that have passed through the anion exchange membrane from the cathode when the electrolytic solution is not supplied, the cathode is disposed between the first separator and the anion exchange membrane and includes a cathode power supply which is a mesh structure, a porous body, or a fiber, the anode is disposed between the second separator and the anion exchange membrane and includes an anode power supply which is a mesh structure, a porous body, or a fiber, and in the stacking direction in which the first separator and the second separator overlap, the thickness of the anode power supply is smaller than the thickness of the cathode power supply. The electrolysis cell according to the present disclosure comprises a first separator, a second separator, an anion exchange membrane disposed between the first separator and the second separator, a cathode disposed between the first separator and the anion exchange membrane, and an anode disposed between the second separator and the anion exchange membrane, wherein the first separator has a flow path for supplying an electrolytic solution to the cathode, and at least a portion of the electrolytic solution supplied from the flow path is consumed in the cathode to produce hydrogen and hydroxide ions, and the second separator has a flow path for supplying an electrolytic solution to the cathode, and at least a portion of the electrolytic solution supplied from the flow path is consumed in the cathode to produce hydrogen and hydroxide ions. The anode does not have a flow path for supplying the electrolyte, and in the anode, oxygen and water are generated by the hydroxide ions that have passed through the anion exchange membrane from the cathode when the electrolyte is not supplied, the first separator has a first surface facing the second separator, the first surface including a first region having a plurality of grooves through which the electrolyte flows, the second separator has a second surface facing the first separator, the second surface has a second region facing the first region, and the second region is formed in a planar shape.

[0008] The electrolysis device according to the present disclosure includes an electrolytic cell, an electrolyte supply unit that supplies the electrolyte to the electrolytic cell, and a power supply unit that applies a voltage to the electrolytic cell. Effect of the Invention

[0010] According to the electrolytic cell and electrolytic device of the present disclosure, it is possible to improve the electrolysis performance. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram showing the overall configuration of an electrolysis device according to a first embodiment of the present disclosure. [Diagram 2] FIG. 1 is a cross-sectional view illustrating a schematic diagram of an electrolysis cell according to a first embodiment of the present disclosure. [Diagram 3] FIG. 3 is a cross-sectional view of the electrolysis cell shown in FIG. 2 taken along line F3-F3. [Figure 4] FIG. 1 is an exploded perspective view showing an electrolysis cell according to a first embodiment of the present disclosure. [Diagram 5] FIG. 1 is a cross-sectional view showing an electrolysis cell according to a first embodiment of the present disclosure. [Figure 6] FIG. 2 is a diagram for explaining the operation of the electrolysis cell according to the first embodiment of the present disclosure. [Figure 7] FIG. 2 is a diagram for explaining the operation of the electrolysis cell according to the first embodiment of the present disclosure. [Figure 8] FIG. 2 is a diagram for explaining the operation of the electrolysis cell according to the first embodiment of the present disclosure. [Figure 9] FIG. 2 is a cross-sectional view showing an electrolysis cell according to a modified example of the first embodiment of the present disclosure. [Figure 10] FIG. 2 is a cross-sectional view showing an electrolysis cell according to a second embodiment of the present disclosure. [Figure 11] FIG. 1 is a cross-sectional view showing an electrolysis cell according to a third embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an electrolysis cell and an electrolysis device according to an embodiment of the present disclosure will be described with reference to the drawings. In the following description, components having the same or similar functions are denoted by the same reference numerals. In the present disclosure, "facing" means that two members overlap when viewed in a certain direction, and may also include a case where another member exists between the two members.

[0013] First, referring to FIG. 5, the Z direction, the X direction, and the Y direction are defined. The Z direction is a direction from a first separator 41 to a second separator 42 described later. The X direction is a direction intersecting (e.g., perpendicular to) the Z direction, and is a direction from a center C of a membrane electrode assembly 43 described later to one end of the membrane electrode assembly 43. The Y direction is a direction intersecting (e.g., perpendicular to) the Z direction and the X direction, and is, for example, a depth direction of the paper surface in FIG. 5. In this embodiment, the Z direction and the Y direction are directions along a horizontal plane. The X direction is a vertical direction. In this disclosure, "external size" means an external size when viewed in the Z direction.

[0014] (First embodiment) <1. Configuration of electrolysis device> FIG. 1 is a schematic diagram showing the overall configuration of an electrolysis device 1 of a first embodiment. The electrolysis device 1 is, for example, a device that generates hydrogen by electrolyzing water contained in an electrolytic solution. The electrolysis device 1 is, for example, an anion exchange membrane (AEM) type electrolysis device. The electrolysis device 1 includes, for example, an electrolysis cell stack 10, an electrolytic solution supply unit 20, and a power supply unit 30.

[0015] (Electrolysis cell stack) The electrolysis cell stack 10 is an assembly of a plurality of electrolysis cells 11. For example, the electrolysis cell stack 10 is formed by arranging a plurality of electrolysis cells 11 in one direction. Each electrolysis cell 11 includes a cathode chamber Sa and an anode chamber Sb. The electrolysis cells 11 will be described in detail later.

[0016] (Electrolyte supply section) The electrolyte supply unit 20 is a supply unit that supplies an electrolyte to each electrolytic cell 11. The electrolyte is, for example, pure water or an alkaline aqueous solution. In this embodiment, for example, an aqueous potassium hydroxide solution (KOH) is used as the electrolyte. The electrolyte supply unit 20 includes a cathode side supply unit 20a and an anode side recovery unit 20b.

[0017] The cathode side supply unit 20a supplies the electrolyte to the cathode chamber Sa of each electrolytic cell 11. The cathode side supply unit 20a includes, for example, an electrolyte tank 21, a first pump 22, a hydrogen recovery unit 23, a hydrogen gas-liquid separation unit 24, a pure water supply tank 25, and piping lines L1 and L2.

[0018] The electrolyte tank 21 stores the electrolyte. A supply port of the electrolyte tank 21 is connected to the cathode chamber Sa of the electrolytic cell 11 via a piping line L1. The first pump 22 is provided in the middle of the piping line L1 and sends the electrolyte stored in the electrolyte tank 21 toward the cathode chamber Sa of the electrolytic cell 11.

[0019] The electrolytic solution sent to the cathode chamber Sa by the first pump 22 may have at least some of the impurity ions removed by a chelating resin tank 22J provided in the piping line L1. The chelating resin tank 22J contains a chelating resin for removing the impurity ions. The chelating resin tank 22J removes at least some of the impurity ions (e.g., metal ions) eluted from the electrolytic cell 11 or the piping lines L1 and L2 into the electrolytic solution (e.g., potassium hydroxide aqueous solution).

[0020] A return port of the electrolyte tank 21 is connected to the cathode chamber Sa of the electrolytic cell 11 via a piping line L2. An electrolyte containing hydrogen generated in the electrolytic cell 11 flows from the electrolytic cell 11 into the electrolyte tank 21. The electrolyte tank 21 is connected to a hydrogen gas-liquid separation unit 24 that separates hydrogen contained in the electrolyte. The hydrogen separated from the electrolyte by the hydrogen gas-liquid separation unit 24 is recovered by a hydrogen recovery unit 23. When the pH of the electrolyte increases (when the hydroxide ion concentration increases) as the water electrolysis process progresses, the pure water supply tank 25 supplies pure water to the electrolyte tank 21 to lower the pH of the electrolyte (to lower the hydroxide ion concentration).

[0021] On the other hand, the anode side recovery unit 20b recovers water and oxygen from the anode chamber Sb of each electrolysis cell 11. The anode side recovery unit 20b includes, for example, an oxygen recovery unit 26, an ion exchange resin tank 27, a second pump 28, an oxygen gas-liquid separation unit 29, and piping lines L3 and L4.

[0022] The oxygen recovery unit 26 is connected to the anode chamber Sb of the electrolytic cell 11 via a piping line L3. Oxygen generated in the electrolytic cell 11 flows into the oxygen recovery unit 26 from the electrolytic cell 11.

[0023] The ion exchange resin tank 27 is connected to the anode chamber Sb of the electrolytic cell 11 via the piping line L4. The water generated in the electrolytic cell 11 flows into the ion exchange resin tank 27 from the electrolytic cell 11. The ion exchange resin tank 27 removes at least a part of the ions contained in the water flowing in from the electrolytic cell 11. That is, the ion exchange resin tank 27 has an ion exchange resin for removing impurity ions. The ion exchange resin tank 27 removes at least a part of the impurity ions (e.g., metal ions or chloride ions) dissolved into the water from the electrolytic cell 11 or the piping line L4. The second pump 28 is provided in the middle of the piping line L4 and sends the water generated in the electrolytic cell 11 toward the pure water supply tank 25. In this embodiment, the liquid flowing in the piping line L4 is pure water rather than an alkaline aqueous solution, so that the ion exchange resin tank 27 can be arranged instead of the chelating resin tank.

[0024] The oxygen gas-liquid separation unit 29 separates oxygen contained in the water generated in the electrolysis cell 11. The oxygen gas-liquid separation unit 29 is provided, for example, in the middle of the piping line L4. In this embodiment, the oxygen gas-liquid separation unit 29 is provided, for example, upstream of the ion exchange resin tank 27 in the water flow direction in the piping line L4. The water separated in the oxygen gas-liquid separation unit 29 passes through the ion exchange resin tank 27 and is sent to the pure water supply tank 25 through the piping line L4 by the second pump 28. The piping line L4 is a piping line that guides the water that has passed through the ion exchange resin tank 27 to be merged with the electrolytic solution to be supplied to the cathode 47 of the electrolysis cell 11. On the other hand, the oxygen separated in the oxygen gas-liquid separation unit 29 is sent to the oxygen recovery unit 26 through the connection line L5 connected in the middle of the piping line L4. That is, the oxygen gas-liquid separation unit 29 separates oxygen contained in the water discharged from the liquid discharge port 42h and merges the separated oxygen with the oxygen discharged from the gas discharge port 42g.

[0025] (Power supply part) The power supply unit 30 is a DC power supply device that applies a voltage to the electrolytic cell 11. The power supply unit 30 applies a DC voltage required for electrolysis of the electrolyte between the anode and cathode of the electrolytic cell 11.

[0026] <2. Structure of electrolysis cell> <2.1 Basic structure of electrolytic cell> Next, the electrolytic cell 11 will be described in detail. Fig. 2 is a cross-sectional view that typically illustrates the electrolysis cell 11. Fig. 3 is a cross-sectional view of the electrolysis cell 11 viewed vertically. The electrolysis cell 11 includes, for example, a first separator 41, a second separator 42, and a membrane electrode assembly 43.

[0027] (First separator) The first separator 41 is a member that defines one side of the internal space S of the electrolysis cell 11. The internal space S is a space that includes a cathode chamber Sa and an anode chamber Sb described below. The first separator 41 is, for example, in the form of a rectangular plate, and is formed of a metal member or a conductive member (such as a carbon material). A negative voltage is applied to the first separator 41 from the power supply unit 30 via, for example, a first current collector 61 (see FIG. 4) described below.

[0028] The first separator 41 has a first end 41e1 (e.g., a lower end) and a second end 41e2 (e.g., an upper end) located on the opposite side to the first end 41e1. The first end 41e1 has a first flow path 41r1. The first flow path 41r1 is connected to the above-mentioned piping line L1, and supplies the electrolytic solution supplied from the outside of the electrolytic cell 11 via the piping line L1 to a cathode 47 (described later) in the cathode chamber Sa. On the other hand, the second end 41e2 has a second flow path 41r2. The second flow path 41r2 is connected to the above-mentioned piping line L2, and discharges the electrolytic solution containing hydrogen by passing through the cathode chamber Sa to the outside of the electrolytic cell 11 via the piping line L2.

[0029] The first separator 41 has a first inner surface (first surface) 41a facing the second separator 42. The first inner surface 41a faces the cathode chamber Sa described later. The first inner surface 41a has a first area A1 in which a plurality of grooves FP1 are provided (see FIG. 3). The plurality of grooves FP1 are flow paths through which the electrolytic solution that has flowed into the electrolytic cell 11 through the first flow path 41r1 flows. The plurality of grooves FP1 are arranged side by side at intervals in the Y direction, for example, and each extends in the X direction (for example, the vertical direction) (see FIG. 3). The electrolytic solution that has flowed into the electrolytic cell 11 through the first flow path 41r1 flows through the plurality of grooves FP1 in a branched manner, passes through the plurality of grooves FP1, and is then discharged from the second flow path 41r2 to the outside of the electrolytic cell 11.

[0030] 2 are merely examples and do not limit the contents of this embodiment. For example, various flow channel structures can be used depending on the size, purpose, and usage environment of the device. This also applies to the structures shown in the other figures.

[0031] (Second separator) The second separator 42 is disposed with an internal space S between it and at least a part of the first separator 41, and is a member that defines the other side of the internal space S. The second separator 42 is, for example, in the shape of a rectangular plate, and is made of a metal member. A positive voltage is applied to the second separator 42 from the power supply unit 30 via a second current collector 62 (see FIG. 4 ), which will be described later. The first separator 41 and the second separator 42 included in the same electrolytic cell 11 form the electrolytic cell 40 of the electrolytic cell 11 as a pair of separators.

[0032] The second separator 42 has a first end 42e1 (e.g., a lower end) and a second end 42e2 (e.g., an upper end) located opposite the first end 42e1. The second separator 42 does not have a flow path for supplying an electrolyte to the anode 48 described later.

[0033] Instead, the second end 42e2 has a gas outlet 42g. The gas outlet 42g is an outlet through which the gas (e.g., oxygen) generated at the anode 48 is mainly discharged. In this embodiment, the gas outlet 42g is connected to a piping line L3 and discharges the gas (e.g., oxygen) generated at the anode 48 to the outside of the electrolysis cell 11.

[0034] On the other hand, the first end 42e1 has a liquid outlet 42h. The liquid outlet 42h is an outlet through which liquid (e.g., water) produced at the anode 48 is mainly discharged. That is, the second separator 42 is provided with the gas outlet 42g and the liquid outlet 42h separately. In this embodiment, the liquid outlet 42h is connected to the piping line L4 and discharges the liquid (e.g., water) produced at the anode 48 to the outside of the electrolysis cell 11.

[0035] In this embodiment, the liquid outlet 42h is provided below the gas outlet 42g. For example, the gas outlet 42g is provided above the vertical center of the anode chamber Sb. The liquid outlet 42h is provided below the vertical center of the anode chamber Sb.

[0036] Of the water and oxygen produced in the anode chamber Sb, the water, which has a larger specific gravity than the oxygen, moves downward due to its own weight and accumulates. This separates the water and oxygen into upper and lower parts in the anode chamber Sb. The oxygen separated in the anode chamber Sb flows into the gas outlet 42g. The water separated in the anode chamber Sb flows into the liquid outlet 42h. Note that oxygen may be mixed in the water that flows into the liquid outlet 42h.

[0037] 3 is a cross-sectional view taken along line F3-F3 of the electrolysis cell 11 shown in FIG. 2. The second separator 42 has a second inner surface (second face) 42a facing the first separator 41. The second inner surface 42a faces the anode chamber Sb described below. In this embodiment, the second inner surface 42a does not have a groove through which the electrolytic solution flows. The second inner surface 42a has a second region A2 facing the first region A1 (the region in which the multiple grooves FP1 are provided) of the first separator 41. The second region A2 is formed in a planar shape.

[0038] For ease of explanation, a configuration is described here in which the first inner surface 41a of the first separator 41 has multiple groove portions FP1. However, for example, the second separator 42 of the electrolysis cell 11 included in the electrolysis cell stack 10 (see FIG. 1) may be a bipolar plate having a similar multiple FP1 (shown by two-dot chain lines in FIG. 3) on the surface 42b opposite to the second inner surface 42a.

[0039] (Membrane electrode assembly) The membrane electrode assembly (MEA) 43 is a structure in which an ion exchange membrane, a catalyst, and a power supply are assembled. The membrane electrode assembly 43 is disposed between the first separator 41 and the second separator 42, and is located in the internal space S. The membrane electrode assembly 43 includes, for example, an ion exchange membrane 51, a cathode catalyst layer 52, a cathode power supply 53, an anode catalyst layer 54, and an anode power supply 55.

[0040] (Ion exchange membrane) The ion exchange membrane 51 is a membrane that selectively allows ions to pass through. The ion exchange membrane 51 is, for example, a solid polymer electrolyte membrane. The ion exchange membrane 51 is, for example, an anion exchange membrane (AEM) that is hydroxide ion conductive. The ion exchange membrane 51 is, for example, a rectangular sheet. The outer size of the ion exchange membrane 51 is smaller than the outer size of the first separator 41 or the second separator 42. The ion exchange membrane 51 is disposed between the first separator 41 and the second separator 42, and is located in the above-mentioned internal space S. The ion exchange membrane 51 has a first surface 51a that faces the first inner surface 41a of the first separator 41, and a second surface 51b that is located on the opposite side to the first surface 51a and faces the second inner surface 42a of the second separator 42. In the internal space S, a cathode chamber Sa is defined between the first surface 51a of the ion exchange membrane 51 and the first inner surface 41a of the first separator 41. In the internal space S, an anode chamber Sb is defined between the second surface 51b of the ion exchange membrane 51 and the second inner surface 42a of the second separator 42.

[0041] The cathode chamber Sa is supplied with the electrolytic solution from the first flow path 41r1 of the first separator 41. In the cathode chamber Sa, when a voltage is applied to the electrolytic cell 11, the following chemical reaction occurs, and hydrogen is produced from the electrolytic solution. That is, at least a portion of the supplied electrolytic solution is consumed in the cathode 47, and hydrogen and hydroxide ions are produced. In this application, "XX is produced" may also include cases where other substances are produced simultaneously with the production of XX. The hydroxide ions produced in the cathode chamber Sa pass through the ion exchange membrane 51 and move from the cathode chamber Sa to the anode chamber Sb. 2H2O+2e - →H2+2OH - …(C1)

[0042] In the anode chamber Sb, when a voltage is applied to the electrolytic cell 11, the following chemical reaction occurs, and oxygen and water are generated by hydroxide ions that have migrated from the cathode chamber Sa to the anode chamber Sb. That is, in the anode 48, oxygen and water are generated by hydroxide ions that have passed through the ion exchange membrane 51 from the cathode 47 in a state in which no electrolyte is supplied. 2OH - →1 / 2O2+H2O+2e - …(Case 2)

[0043] As a result, the following chemical reactions occur in the electrolytic cell 11 as a whole: H2O→H2+1 / 2O2…(Chem.3)

[0044] (Cathode catalyst layer) The cathode catalyst layer 52 is a layer that promotes a chemical reaction in the cathode chamber Sa described above. The cathode catalyst layer 52 is, for example, a rectangular sheet. The cathode catalyst layer 52 is disposed in the cathode chamber Sa and is adjacent to the ion exchange membrane 51 in the Z direction. In the present application, the term "adjacent" is not limited to the case where two members are adjacent to each other independently, but may also include the case where at least a part of one of the two members penetrates into the other member. For example, a part of the cathode catalyst layer 52 may penetrate into the surface portion of the ion exchange membrane 51. In this embodiment, the cathode catalyst layer 52 is provided on the first surface 51a of the ion exchange membrane 51. For example, the cathode catalyst layer 52 is formed by applying a material of the cathode catalyst layer 52 to the first surface 51a of the ion exchange membrane 51. A negative voltage is applied to the cathode catalyst layer 52 from the power supply unit 30 via the first separator 41 and the cathode power supply 53, and the cathode catalyst layer 52 functions as a part of the cathode 47 of the electrolysis cell 11. The material of the cathode catalyst layer 52 may be any material that promotes the chemical reaction in the cathode chamber Sa described above, and various materials may be used.

[0045] (Cathode feeder) The cathode power supply 53 is an electrical connection part that transmits the voltage applied to the first separator 41 to the cathode catalyst layer 52. The cathode power supply 53 is disposed in the cathode chamber Sa. The cathode power supply 53 is located between the first inner surface 41a of the first separator 41 and the cathode catalyst layer 52, and contacts the first inner surface 41a of the first separator 41 and the cathode catalyst layer 52, respectively. The cathode power supply 53 has a structure that allows the electrolyte and gas to pass through the inside. The cathode power supply 53 is formed of, for example, a metal mesh structure, a sintered body (porous body), or a fiber. In this embodiment, the outer size of the cathode power supply 53 is the same as the outer size of the cathode catalyst layer 52. In this embodiment, the cathode catalyst layer 52 and the cathode power supply 53 form the cathode 47 of the electrolysis cell 11.

[0046] (Anode catalyst layer) The anode catalyst layer 54 is a layer that promotes the chemical reaction in the anode chamber Sb described above. The anode catalyst layer 54 is, for example, a rectangular sheet. The anode catalyst layer 54 is disposed in the anode chamber Sb and is adjacent to the ion exchange membrane 51 in the Z direction. For example, a part of the anode catalyst layer 54 may be embedded in the surface portion of the ion exchange membrane 51. In this embodiment, the anode catalyst layer 54 is provided on the second surface 51b of the ion exchange membrane 51. For example, the anode catalyst layer 54 is formed by applying the material of the anode catalyst layer 54 to the second surface 51b of the ion exchange membrane 51. A positive voltage is applied from the power supply unit 30 via the second separator 42 and the anode power supply 55 to the anode catalyst layer 54, and the anode catalyst layer 54 functions as a part of the anode 48 of the electrolysis cell 11. The material of the anode catalyst layer 54 may be any material that promotes the chemical reaction in the anode chamber Sb described above, and various materials can be used.

[0047] (anode current collector) The anode power supply 55 is an electrical connection part that transmits the voltage applied to the second separator 42 to the anode catalyst layer 54. The anode power supply 55 is disposed in the anode chamber Sb. The anode power supply 55 is located between the second inner surface 42a of the second separator 42 and the anode catalyst layer 54, and is in contact with the second inner surface 42a of the second separator 42 and the anode catalyst layer 54, respectively. The anode power supply 55 has a structure that allows the electrolyte and gas to pass through the inside. The anode power supply 55 is formed of, for example, a metal mesh structure, a sintered body (porous body), or a fiber. In this embodiment, the outer size of the anode power supply 55 is the same as the outer size of the anode catalyst layer 54. In this embodiment, the average size of the multiple holes in the anode power supply 55 is larger than the average size of the multiple holes in the cathode power supply 53. For example, when both the cathode current collector 53 and the anode current collector 55 have mesh structures, the anode current collector 55 has a coarser mesh structure than the cathode current collector 53. In this embodiment, the porosity of the anode current collector 55 is greater than the porosity of the cathode current collector 53. In this embodiment, the anode catalyst layer 54 and the anode current collector 55 form the anode 48 of the electrolysis cell 11.

[0048] 4 is an exploded perspective view showing the electrolysis cell 11. In addition to the components described above, the electrolysis cell 11 includes, for example, a first current collector 61, a second current collector 62, a first insulator 63, a second insulator 64, a first end plate 65, and a second end plate 66.

[0049] (First current collector) The first current collector 61 is an electrical connection part that transmits a negative voltage applied from the power supply unit 30 to the first separator 41. The first current collector 61 is a metal plate member (e.g., a copper plate). The first current collector 61 contacts the first separator 41 from the side opposite to the internal space S of the electrolytic cell 11, for example, and is electrically connected to the first separator 41. A negative voltage required for electrolysis in the electrolytic cell 11 is applied to the first current collector 61 from the power supply unit 30. The first current collector 61 may be shared by multiple electrolytic cells 11 included in the electrolytic cell stack 10.

[0050] (Second current collector) The second current collector 62 is an electrical connection part that transmits the positive voltage applied from the power supply unit 30 to the second separator 42. The second current collector 62 is a metal plate member (e.g., a copper plate). The second current collector 62 contacts the second separator 42 from the side opposite to the internal space S of the electrolytic cell 11, for example, and is electrically connected to the second separator 42. A positive voltage required for electrolysis in the electrolytic cell 11 is applied to the second current collector 62 from the power supply unit 30. The second current collector 62 may be shared by multiple electrolytic cells 11 included in the electrolytic cell stack 10.

[0051] (First insulating material) The first insulating material 63 is located between the first current collector 61 and the first end plate 65. The outer size of the first insulating material 63 is larger than the outer size of the first current collector 61, for example.

[0052] (Second insulating material) The second insulating material 64 is located between the second current collector 62 and the second end plate 66. The outer size of the second insulating material 64 is larger than the outer size of the second current collector 62, for example.

[0053] (First end plate) The first end plate 65 is located on the opposite side to the first insulating material 63 with respect to the internal space S of the electrolysis cell 11. The outer size of the first end plate 65 is the same as or larger than the outer size of the first insulating material 63, for example.

[0054] (Second end plate) The second end plate 66 is located on the opposite side to the second insulating material 64 with respect to the internal space S of the electrolysis cell 11. The outer size of the second end plate 66 is, for example, the same as or larger than the outer size of the second insulating material 64. In this embodiment, by fastening the first end plate 65 and the second end plate 66 with a fastening member (not shown), a pressing force acts on the first separator 41 and the second separator 42 in opposing directions, and the electrolysis cell 11 is integrated.

[0055] The electrolysis cell 11 is not limited to the above configuration. For example, when a plurality of electrolysis cells 11 are arranged side by side in the electrolysis cell stack 10, two adjacent electrolysis cells 11 among the plurality of electrolysis cells 11 may share the first separator 41 and the second separator 42, respectively. In this case, there may be no current collector (first current collector 61 or second current collector 62), no insulator (first insulator 63 or second insulator 64), and no end plate (first end plate 65 or second end plate 66) between the two adjacent electrolysis cells 11.

[0056] <2.2 Outer structure of electrolysis cell> 5 is a cross-sectional view showing the electrolysis cell 11. In this embodiment, the outer size of the ion exchange membrane 51 is larger than the outer size of the cathode power supply 53 and the anode power supply 55. The ion exchange membrane 51 protrudes outward (toward the outer periphery) from the cathode catalyst layer 52 and the cathode power supply 53 in a direction (e.g., X direction or Y direction) perpendicular to the thickness direction (Z direction) of the membrane electrode assembly 43. In this disclosure, the term "outer side" or "outer periphery side" refers to the side away from the center C of the membrane electrode assembly 43 in a direction (e.g., X direction or Y direction) perpendicular to the thickness direction (Z direction) of the membrane electrode assembly 43.

[0057] 5, the electrolysis cell 11 has, for example, a support part 70 and a sealing part 80. The support part 70 is a member that supports the membrane electrode assembly 43 inside the electrolysis cell 11. The sealing part 80 is a member that closes the internal space S between the first separator 41 and the second separator 42. These will be described below.

[0058] (Support part) The support portion 70 is disposed between the first separator 41 and the second separator 42. The support portion 70 is located inside (on the inner circumferential side) of the outer edge portion 51e of the ion exchange membrane 51, and supports the ion exchange membrane 51. The support portion 70 includes, for example, a first support portion 71 and a second support portion 72.

[0059] The first support part 71 is a support part on the cathode side. The first support part 71 is disposed between the first inner surface 41a of the first separator 41 and the first surface 51a of the ion exchange membrane 51. The first support part 71 is sandwiched between the first inner surface 41a (or the first insulating material 63) of the first separator 41 and the first surface 51a of the ion exchange membrane 51 at a position outside (on the outer periphery) of the cathode catalyst layer 52 and the cathode power supply 53, and supports the ion exchange membrane 51 against the first inner surface 41a of the first separator 41.

[0060] The second support 72 is a support on the anode side. The second support 72 is disposed between the second inner surface 42a of the second separator 42 and the third surface 52a of the ion exchange membrane 51. The second support 72 is sandwiched between the second inner surface 42a of the second separator 42 and the third surface 52a of the ion exchange membrane 51 at a position outside (on the outer periphery) of the anode catalyst layer 54 and the anode power supplier 55, and supports the ion exchange membrane 51 against the second inner surface 42a of the second separator 42.

[0061] (Sealing part) The sealing portion 80 is disposed between the first separator 41 and the second separator 42. The sealing portion 80 is located outside (on the outer periphery side) of the outer edge portion 51e of the ion exchange membrane 51, and seals the internal space S of the electrolysis cell 11. In this embodiment, the sealing portion 80 includes a first sealing portion 81 and a second sealing portion 82. However, the first sealing portion 81 and the second sealing portion 82 may be integrally formed. That is, the first sealing portion 81 and the second sealing portion 82 may be a single member.

[0062] The first sealing portion 81 is a sealing portion on the cathode side. The first sealing portion 81 is located outside (on the outer periphery side) of the outer edge portion 51e of the ion exchange membrane 51. The first sealing portion 81 is sandwiched between the first inner surface 41a of the first separator 41 and the second sealing portion 82, and seals a part of the outer periphery side of the internal space S.

[0063] The second sealing portion 82 is a sealing portion on the anode side. The second sealing portion 82 is located outside the outer edge portion 51e of the ion exchange membrane 51. The second sealing portion 82 is sandwiched between the second inner surface 42a of the second separator 42 and the first sealing portion 81, and seals a part of the outer circumferential side of the internal space S.

[0064] <3. Effects> In this embodiment, the first flow path 41r1 is formed only in the first separator 41, and the electrolyte is supplied to the cathode 47. On the other hand, the second separator 42 does not have a flow path through which the electrolyte flows, and the electrolyte is not supplied to the anode 48. According to this configuration, at least a part of the electrolyte supplied from the first flow path 41r1 is consumed in the cathode 47 to generate hydrogen and hydroxide ions, and in the anode 48, oxygen and water are generated by the hydroxide ions that have passed through the ion exchange membrane 51 from the cathode 47 in a state in which the electrolyte is not supplied. According to this configuration, the amount of electrolyte required to operate the electrolysis device 1 is half compared to the case in which the electrolyte is supplied to both the cathode 47 and the anode 48, and the operating cost of the electrolysis device 1 can be reduced. Furthermore, according to the above configuration, various configurations required to supply the electrolyte are not required on the anode 48 side, which leads to cost reduction. Furthermore, according to the above configuration, the hydrogen ion concentration (pH) of the electrolyte, which changes with the operation of the electrolysis device 1, can be managed only on the cathode side. This can reduce the management burden during operation, as compared with a case in which an electrolyte is supplied to both the cathode 47 and the anode 48, respectively.

[0065] Furthermore, according to the above configuration, the electrolytic solution required for producing hydrogen and hydroxide ions on the cathode 47 side is supplied to the cathode 47 side, not to the anode 48 side. Therefore, the electrolytic solution consumed for producing hydrogen and hydroxide ions on the cathode 47 side is supplied to the cathode 47 without passing through the ion exchange membrane 51. As a result, loss in the electrolytic cell 11 can be reduced, and the electrolytic performance of the electrolytic cell 11 can be improved.

[0066] In this embodiment, the gas outlet 42g and the liquid outlet 42h are separately provided in the second separator 42. As a result, oxygen and water generated on the anode 48 side are discharged separately from the gas outlet 42g and the liquid outlet 42h. This makes it possible to obtain oxygen and water in a state separated to some extent from inside the electrolysis cell 11. Therefore, compared to the case where oxygen and water are discharged in a mixed state from inside the electrolysis cell 11, there is less need to provide a gas-liquid separation mechanism for separating oxygen and water outside the electrolysis cell 11, which leads to cost reduction.

[0067] In this embodiment, the liquid outlet 42h is provided below the gas outlet 42g. According to this configuration, water falls under its own weight in the electrolysis cell 11, so that oxygen and water are separated, and the water accumulates in the lower part of the electrolysis cell 11, and the oxygen accumulates in the upper part of the electrolysis cell 11. By providing the liquid outlet 42h below the gas outlet 42g, the water that accumulates in the lower part of the electrolysis cell 11 can be discharged from the liquid outlet 42h, and the oxygen that accumulates in the upper part of the electrolysis cell 11 can be discharged from the gas outlet 42g. In this way, oxygen and water can be efficiently separated without providing a gas-liquid separation mechanism in the electrolysis cell 11. From another point of view, according to the above configuration, it is possible to prevent water from flowing into the gas outlet 42g, and to smoothly discharge gas (oxygen) from the gas outlet 42g. This makes it possible to prevent the gas outlet 42g from being blocked by water, which increases the pressure in the anode chamber Sb and damages the ion exchange membrane 51.

[0068] In this embodiment, the gas outlet 42g is provided above the vertical center of the anode chamber Sb, so that oxygen accumulating in the upper part of the anode chamber Sb can be smoothly discharged from the gas outlet 42g. In addition, the liquid outlet 42h is provided below the vertical center of the anode chamber Sb, so that water accumulating in the lower part of the anode chamber Sb can be smoothly discharged from the liquid outlet 42h. Here, if the liquid outlet 42h is provided above the vertical center of the anode chamber Sb, the area below the liquid outlet 42h in the anode chamber Sb will be filled with pure water. In this case, the difference in hydrogen ion concentration (pH) between the cathode 47 side where the electrolytic solution exists and the anode 48 side where the pure water exists will increase, and the electrolysis performance of the electrolysis cell 11 will decrease. Therefore, in this embodiment, the liquid outlet 42h is provided below the vertical center of the anode chamber Sb, so that the anode chamber Sb is prevented from being filled with water. This makes it possible to improve the electrolysis performance of the electrolysis cell 11.

[0069] In this embodiment, the average size of the holes in the anode power supply 55 is larger than the average size of the holes in the cathode power supply 53. With this configuration, the electrolyte is supplied only to the cathode 47 side, and not to the anode 48 side, so that the electrolyte does not pass through the anode power supply 55 on the anode 48 side. Therefore, by making the average size of the holes in the anode power supply 55 larger than the average size of the holes in the cathode power supply 53, the gas (air) generated at the anode 48 can easily move through the anode power supply 55 toward the gas exhaust port 42g. This can improve the electrolysis performance of the electrolysis cell 11.

[0070] In this embodiment, the porosity of the anode power supply 55 is greater than the porosity of the cathode power supply 53. With this configuration, the electrolyte is supplied only to the cathode 47 side, and not to the anode 48 side, so that the electrolyte does not pass through the anode power supply 55 on the anode 48 side. Therefore, by making the porosity of the anode power supply 55 greater than the porosity of the cathode power supply 53, the gas (air) generated at the anode 48 can easily move through the anode power supply 55 toward the gas outlet 42g. This can further improve the electrolysis performance of the electrolysis cell 11.

[0071] In this embodiment, the first inner surface 41a of the first separator 41 includes a first region A1 having a plurality of grooves FP1. The second inner surface 42a of the second separator 42 has a second region A2 facing the first region A1 of the first separator 41. The second region A2 is formed in a planar shape. With this configuration, water generated at the anode is likely to move toward the liquid outlet 42h through the planar second region A2. This can further improve the electrolysis performance of the electrolysis cell 11. In addition, by forming the second region A2 in a planar shape, the structure of the second separator 42 can be simplified, leading to cost reduction. In addition, when the entire second separator 42 is formed in a flat plate shape, the second separator 42 can be made thinner than when the second separator 42 has grooves. In this case, the electrolysis cell stack 10 can be made smaller in size.

[0072] In this embodiment, the electrolysis device 1 further includes a gas-liquid separator 29 that separates gas contained in the liquid discharged from the liquid outlet 42h and merges the separated gas with the gas discharged from the gas outlet 42g. With this configuration, the gas contained in the liquid discharged from the liquid outlet 42h is separated from the liquid by the gas-liquid separator 29 and merges with the gas discharged from the gas outlet 42g. This makes it possible to more reliably separate the gas and liquid discharged from the electrolysis cell 11.

[0073] In this embodiment, an ion exchange resin tank 27 is provided to remove at least a part of the ions contained in the water discharged from the second separator 42, and the water that has passed through the ion exchange resin tank 27 is merged with the electrolytic solution to be supplied to the cathode 47. With this configuration, the water discharged from the second separator 42 can be purified before being supplied to the cathode 47. As a result, the water generated on the anode 48 side can be effectively used as at least a part of the electrolytic solution to be supplied to the cathode 47, and the amount of water used in the electrolytic device 1 can be reduced. In addition, the provision of the ion exchange resin tank 27 can remove at least a part of the impurity ions dissolved into the water from the electrolytic cell 11 and the like. In this embodiment, the liquid flowing through the piping line L4 is water, not an electrolytic solution, and therefore the impurity ions dissolved from the electrolytic cell 11 can be removed using an appropriate ion exchange resin selected from various ion exchange resins, not limited to a chelating resin. As a result, an electrolytic device 1 that is less likely to malfunction and has excellent durability can be provided.

[0074] <4. Effect> 6, 7 and 8 are diagrams for explaining the operation of the electrolysis cell 11 of this embodiment. Here, a structure in which the electrolytic solution is supplied only to the above-mentioned cathode 47, and not to the anode 48, will be described as an example. In contrast, a structure in which the electrolytic solution is supplied to both the cathode 47 and the anode 48 will be described as a first comparative example.

[0075] Here, for each of the Example and the first Comparative Example, a voltage was applied from the power supply unit 30, and the relationship (IV characteristics) between the current density from the power supply unit 30 and the cell voltage generated in the electrolytic cell 11 was measured. The "cell voltage" refers to the potential difference between the first separator 41 and the second separator 42. As a result, as shown in FIG. 6, the inventors confirmed that the Example in which the electrolytic solution was supplied only to the cathode 47 had a slightly higher cell voltage than the first Comparative Example, but had approximately the same electrolytic performance.

[0076] Furthermore, a durability test was conducted for each of the Example and the first Comparative Example in which a voltage was continuously applied from the power supply unit 30 for a long period of time, and the relationship between the current density from the power supply unit 30 and the cell voltage generated in the electrolytic cell 11 was measured before and after the durability test. As a result, as shown in FIG. 7 , the Example had a higher electrolytic voltage than the first Comparative Example before the durability test, but after the durability test, the Example had a lower electrolytic voltage than the first Comparative Example, and good electrolytic performance was obtained. As a result, the inventors confirmed that, assuming actual use during which normal operation continues, the electrolytic cell of the Example can obtain better electrolytic performance than the first Comparative Example.

[0077] As a second comparative example, an electrolytic cell was prepared in a structure in which the electrolytic solution was supplied only to the anode 48, and not to the cathode 47. In each of the example, the first comparative example, and the second comparative example, a voltage was applied from the power supply unit 30, and the relationship between the current density from the power supply unit 30 and the cell voltage generated in the electrolytic cell 11 was measured. As a result, as shown in FIG. 8, the inventors confirmed that in the second comparative example in which the electrolytic solution was supplied only to the anode 48, the cell voltage was higher and the electrolytic performance was reduced compared to the example and the first comparative example.

[0078] <5. Modifications> Next, a modification of the first embodiment will be described. 9 is a cross-sectional view showing an electrolysis cell 11A according to a modified example of the first embodiment. In the above-described first embodiment, the average size and porosity of the multiple holes are made different between the anode current collector 55 and the cathode current collector 53. Alternatively / in addition to this, in this modified example, the thickness T1 of the anode current collector 55 is smaller than the thickness T2 of the cathode current collector 53 in the stacking direction (Z direction) in which the first separator 41 and the second separator 42 overlap.

[0079] In this configuration, the electrolyte is supplied only to the cathode 47 side, and not to the anode 48 side, so that the electrolyte does not pass through the anode power supplier 55. Therefore, even if the thickness T1 of the anode power supplier 55 is made smaller than the thickness T2 of the cathode power supplier 53, the anode power supplier 55 can fully function as the anode power supplier 55. This allows the electrolytic cell 11 to be made smaller (thinner) and less expensive.

[0080] Second embodiment Next, a second embodiment will be described. The second embodiment differs from the first embodiment in that an outlet 90 for discharging oxygen and water is provided on the anode 48 side. Note that the configuration other than that described below is the same as that of the first embodiment.

[0081] 10 is a cross-sectional view showing an electrolysis cell 11B of the second embodiment. In this embodiment, the second separator 42 has an outlet 90 through which oxygen and water are discharged together. In this embodiment, the outlet 90 is formed such that the upper end of the outlet 90 is located above the water level WS of the water accumulated in the anode chamber Sb in a steady operating state of the electrolysis cell 11B. "The outlet is formed such that the upper end of the outlet is located above the water level WS of the water accumulated in the anode chamber" means, for example, that the opening area of ​​the outlet 90 is set such that the flow rate of water flowing out from the outlet 90 to the outside per unit time is greater than the amount of water produced in the anode chamber Sb per unit time in a steady operating state.

[0082] In this embodiment, the outlet 90 is provided at the vertical center of the anode chamber Sb or below the center. The oxygen and water discharged from the outlet 90 to the outside of the electrolytic cell 11B are sent to the oxygen-gas-liquid separation section 29 through a piping line L6, where the oxygen and water are separated.

[0083] In this embodiment, the second separator 42 has an outlet 90 through which oxygen and water are discharged. As a result, oxygen and water generated in the anode chamber Sb are discharged from the outlet 90 in a mixed state. The upper end of the outlet 90 is located above the water level WS of the water accumulated in the anode chamber Sb when the electrolysis cell 11 is in a steady operating state. Therefore, oxygen that accumulates above the water level WS of the water accumulated in the anode chamber Sb when the electrolysis cell 11 is in a steady operating state can be constantly discharged through the outlet 90. This makes it possible to prevent the outlet 90 from being blocked by water, causing an increase in air pressure in the anode chamber Sb and damaging the ion exchange membrane 51.

[0084] Here, if the outlet 90 is disposed above the vertical center of the anode chamber Sb, the area below the outlet 90 in the anode chamber Sb will be filled with pure water. In this case, the difference in hydrogen ion concentration (pH) between the cathode 47 side where the electrolytic solution is present and the anode 48 side where the pure water is present will increase, and the electrolysis performance of the electrolysis cell 11 will deteriorate. Therefore, in this embodiment, the outlet 90h is provided at the vertical center of the anode chamber Sb or below the center. This prevents most of the anode chamber Sb from being filled with water, and improves the electrolysis performance of the electrolysis cell 11.

[0085] Third embodiment Next, a third embodiment will be described. The third embodiment differs from the second embodiment in that it includes a suction device 95 connected to the outlet 90. Note that the configuration other than that described below is the same as that of the second embodiment.

[0086] 11 is a cross-sectional view showing an electrolytic cell 11C of a third embodiment. In this embodiment, the electrolytic cell 11C further includes a suction device 95 connected to an outlet 90. The suction device 95 is, for example, a pump, and sucks oxygen and water through the outlet 90 toward the outside of the electrolytic cell 11C. This allows the water and oxygen generated in the anode chamber Sb to be forcibly discharged from the outlet 90 even when an outlet 90 is provided for discharging water and oxygen together. This allows oxygen and water to be efficiently discharged while suppressing a pressure increase in the electrolytic cell 11C.

[0087] (Other embodiments) Although the embodiments of the present disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like that do not depart from the gist of the present disclosure are also included.

[0088] <Additional Notes> The electrolytic cells 11, 11A, 11B, and 11C and the electrolytic device 1 described in each embodiment can be understood, for example, as follows.

[0089] (1) The electrolytic cells 11, 11A, 11B, and 11C of the first embodiment include a first separator 41, a second separator 42, an anion exchange membrane 51 disposed between the first separator 41 and the second separator 42, a cathode 47 disposed between the first separator 41 and the anion exchange membrane 51, and an anode 48 disposed between the second separator 42 and the anion exchange membrane 51. The first separator 41 has a first flow path 41r1 for supplying an electrolytic solution to the cathode 47. In the cathode 47, at least a part of the electrolytic solution supplied from the first flow path 41r1 is consumed to generate hydrogen and hydroxide ions. The second separator 42 does not have a flow path for supplying an electrolytic solution to the anode 48. In the anode 48, oxygen and water are generated by hydroxide ions that have passed through the anion exchange membrane 51 from the cathode 47 in a state in which no electrolytic solution is supplied. According to this configuration, the first flow path 41r1 is formed only in the first separator 41, and the electrolytic solution is supplied to the cathode 47. The second separator 42 does not have a flow path, and the electrolytic solution is not supplied to the anode 48. In the cathode 47, at least a part of the electrolytic solution supplied from the first flow path 41r1 is consumed, thereby generating hydrogen and hydroxide ions. That is, the electrolytic solution required to generate hydrogen and hydroxide ions on the cathode 47 side is supplied to the cathode 47 side, not to the anode 48 side. Therefore, the electrolytic solution for generating hydrogen and hydroxide ions on the cathode 47 side does not pass through the anion exchange membrane 51, and no loss due to resistance occurs. As a result, the electrolytic performance of the electrolytic cells 11, 11A, 11B, and 11C can be improved.

[0090] (2) The electrolytic cell 11 of the second embodiment is the electrolytic cell 11, 11A of (1), in which the second separator 42 has a gas outlet 42g through which oxygen is mainly discharged and a liquid outlet 42h through which water is mainly discharged. The gas outlet 42g and the liquid outlet 42h are separately provided on the second separator 42. With this configuration, oxygen and water generated on the anode 48 side are separately discharged from the gas outlet 42g and the liquid outlet 42h. This allows oxygen and water to be smoothly discharged from the electrolytic cell 11. For example, compared to a case in which oxygen and water are discharged from the electrolytic cell 11 in a mixed state, there is less need to provide a gas-liquid separation mechanism for separating oxygen and water outside the electrolytic cell 11, which leads to cost reduction.

[0091] (3) The electrolytic cell 11, 11A of the third embodiment is the electrolytic cell 11, 11A of (2), in which the liquid outlet 42h is provided below the gas outlet 42g. With this configuration, oxygen and water are separated in the electrolytic cell 11 as the water falls under its own weight, and the water accumulates in the lower part of the electrolytic cell 11 and the oxygen accumulates in the upper part of the electrolytic cell 11. By providing the liquid outlet 42h below the gas outlet 42g, the water that accumulates in the lower part of the electrolytic cell 11 can be discharged from the liquid outlet 42h, and the oxygen that accumulates in the upper part of the electrolytic cell 11 can be discharged from the gas outlet 42g. In this way, oxygen and water can be efficiently separated without providing a gas-liquid separation mechanism in the electrolytic cell 11.

[0092] (4) The electrolytic cell 11, 11A of the fourth embodiment is the electrolytic cell 11, 11A of (2) or (3), in which an anode chamber Sb is defined between the second separator 42 and the anion exchange membrane 51. The gas outlet 42g is provided above the vertical center of the anode chamber Sb. The liquid outlet 42h is provided below the vertical center of the anode chamber Sb. With this configuration, by providing the gas outlet 42g above the vertical center of the anode chamber Sb, oxygen that accumulates in the upper part of the anode chamber Sb can be smoothly discharged from the gas outlet 42g. In addition, by providing the liquid outlet 42h below the vertical center of the anode chamber Sb, water that accumulates in the lower part of the anode chamber Sb can be smoothly discharged from the liquid outlet 42h.

[0093] (5) The electrolytic cells 11B, 11C of the fifth embodiment are the electrolytic cells 11B, 11C of (1), in which an anode chamber Sb is defined between the second separator 42 and the anion exchange membrane 51. The second separator 42 has an outlet 90 through which oxygen and water are discharged. The outlet 90 is formed such that the upper end of the outlet 90 is located above the water level of the water accumulated in the anode chamber Sb in the steady operation state of the electrolytic cells 11B, 11C. According to this configuration, the second separator 42 has the outlet 90 through which oxygen and water are discharged. As a result, the oxygen and water generated in the anode chamber Sb are discharged from the outlet 90 in a mixed state. The upper end of the outlet 90 is located above the water level WS of the water accumulated in the anode chamber Sb in the steady operation state of the electrolytic cell 11B. Therefore, oxygen that accumulates above the water level WS in the anode chamber Sb during steady operation of the electrolytic cell 11B can always be discharged through the outlet 90. The water that accumulates in the anode chamber Sb can be discharged from the outlet 90 when the water level is located above the lower end of the outlet 90. In this way, even in a configuration with one outlet 90, the water and oxygen that have separated in the anode chamber Sb due to the weight of the water can be discharged in a separated state.

[0094] (6) The electrolytic cell 11B, 11C of the sixth embodiment is the electrolytic cell 11B, 11C of (1) or (5), in which an anode chamber Sb is defined between the second separator 42 and the anion exchange membrane 51. The second separator 42 has an outlet 90 through which oxygen and water are discharged. The outlet 90 is provided at the vertical center of the anode chamber Sb or below the center. With this configuration, oxygen and water generated in the anode chamber Sb are discharged from the outlet 90 in a mixed state. When the outlet 90 is provided at the vertical center of the anode chamber Sb or below the center, water is discharged from the outlet 90 when the water level WS of the water accumulated in the anode chamber Sb reaches a position above the lower end of the outlet 90. Oxygen accumulated above the water in the anode chamber Sb is discharged through the outlet 90. In this manner, even in a configuration having one exhaust port 90, the water and oxygen separated due to the weight of the water in the anode chamber Sb can be discharged in a separated state.

[0095] (7) The electrolytic cell 11, 11A, 11B, 11C of the seventh embodiment is any one of the electrolytic cells 11, 11A, 11B, 11C of (1) to (6), in which the cathode 47 is disposed between the first separator 41 and the anion exchange membrane 51 and includes a cathode current collector 53 which is a mesh structure, a porous body, or a fiber. The anode 48 is disposed between the second separator 42 and the anion exchange membrane 51 and includes an anode current collector 55 which is a mesh structure, a porous body, or a fiber. The average size of the multiple holes in the anode current collector 55 is larger than the average size of the multiple holes in the cathode current collector 53. With this configuration, the electrolyte is supplied only to the cathode 47 side, and the electrolyte is not supplied to the anode 48 side. Therefore, the electrolyte does not pass through the anode current collector 55 on the anode 48 side. Therefore, by making the average size of the multiple holes in the anode power supply 55 larger than the average size of the multiple holes in the cathode power supply 53, for example, it is possible to promote separation of gas and liquid in the anode chamber Sb and promote discharge of gas and liquid, thereby improving the operating efficiency of the electrolysis cells 11, 11A, 11B, and 11C.

[0096] (8) The electrolytic cell 11, 11A, 11B, 11C of the eighth embodiment is any one of the electrolytic cells 11, 11A, 11B, 11C of (1) to (7), in which the cathode 47 is disposed between the first separator 41 and the anion exchange membrane 51 and includes a cathode current collector 53 which is a mesh structure, a porous body, or a fiber. The anode 48 is disposed between the second separator 42 and the anion exchange membrane 51 and includes an anode current collector 55 which is a mesh structure, a porous body, or a fiber. The porosity of the anode current collector 55 is larger than the porosity of the cathode current collector 53. According to this configuration, the electrolyte is supplied only to the cathode 47 side, and the electrolyte is not supplied to the anode 48 side. Therefore, the electrolyte does not pass through the anode current collector 55 on the anode 48 side. Therefore, by making the porosity of the anode current collector 55 larger than that of the cathode current collector 53, for example, it is possible to promote separation of gas and liquid in the anode chamber Sb and promote discharge of the gas and liquid, thereby improving the operating efficiency of the electrolytic cells 11, 11A, 11B, and 11C.

[0097] (9) The electrolytic cell 11A of the ninth embodiment is any one of the electrolytic cells 11A of (1) to (8), in which the cathode 47 is disposed between the first separator 41 and the anion exchange membrane 51 and includes a cathode current collector 53 which is a mesh structure, a porous body, or a fiber. The anode 48 is disposed between the second separator 42 and the anion exchange membrane 51 and includes an anode current collector 55 which is a mesh structure, a porous body, or a fiber. In the stacking direction in which the first separator 41 and the second separator 42 overlap, the thickness T1 of the anode current collector 55 is smaller than the thickness T2 of the cathode current collector 53. With this configuration, the electrolyte is supplied only to the cathode 47 side, and the electrolyte is not supplied to the anode 48 side. Therefore, the electrolyte does not pass through the anode current collector 55. Therefore, even if the thickness T1 of the anode power supplier 55 in the stacking direction in which the first separator 41 and the second separator 42 overlap is made smaller than the thickness T2 of the cathode power supplier 53, the anode power supplier 55 can fully function as the anode power supplier 55. This allows the electrolysis cell 11A to be made smaller (thinner) and less expensive.

[0098] (10) The electrolytic cell 11, 11A, 11B, 11C of the tenth embodiment is any one of the electrolytic cells 11, 11A, 11B, 11C of (1) to (9), in which the first separator 41 has a first inner surface 41a facing the second separator 42. The first inner surface 41a includes a first region A1 in which a plurality of grooves FP1 through which the electrolytic solution flows are provided. The second separator 42 has a second inner surface 42a facing the first separator 41. The second inner surface 42a has a second region A2 facing the first region A1. The second region A2 is formed in a planar shape. This simplifies the structure of the first separator 41, and allows the electrolytic cell 11A to be made smaller (thinner) and less expensive.

[0099] (11) The electrolysis device 1 of the eleventh aspect includes the electrolysis cells 11, 11A, 11B, 11C of (1) or (2), an electrolyte supply unit 20 that supplies electrolyte to the electrolysis cells 11, 11A, 11B, 11C, and a power supply unit 30 that applies voltage to the electrolysis cells 11, 11A, 11B, 11C. This configuration can improve the electrolysis performance of the electrolysis device 1 including the electrolysis cells 11, 11A, 11B, 11C.

[0100] (12) The electrolysis device 1 of the twelfth embodiment is the electrolysis device 1 of (11), in which the second separator 42 has a gas outlet 42g through which the gas generated at the anode 48 is mainly discharged, and a liquid outlet 42h through which the liquid generated at the anode 48 is mainly discharged. The gas outlet 42g and the liquid outlet 42h are separately provided on the second separator 42. The electrolysis device 1 further includes a gas-liquid separation unit 29 that separates the gas contained in the liquid discharged from the liquid outlet 42h and merges the separated gas with the gas discharged from the gas outlet 42g. According to this configuration, the gas and liquid generated on the anode 48 side are discharged separately from the gas outlet 42g and the liquid outlet 42h. The gas contained in the liquid discharged from the liquid outlet 42h is separated from the liquid by the gas-liquid separation unit 29 and merges with the gas discharged from the gas outlet 42g. This makes it possible to more reliably separate the gas and liquid discharged from the electrolysis cell 11.

[0101] (13) The electrolysis device 1 of a thirteenth aspect is the electrolysis device 1 of (11) or (12), further comprising an ion exchange resin tank 27 into which the water discharged from the second separator 42 flows and into which at least a portion of the ions contained in the water are removed, and a piping line L4 that guides the water that has passed through the ion exchange resin tank 27 to join with the electrolytic solution to be supplied to the cathode 47. With this configuration, at least a portion of the ions contained in the water discharged from the second separator 42 are removed by the ion exchange resin tank 27. This makes it possible to remove impurities from the water discharged from the second separator 42. The water purified by passing through the ion exchange resin tank 27 is joined with the electrolytic solution to be supplied to the cathode 47 through the piping line L4. This makes it possible to effectively use the water produced on the anode 48 side as at least a portion of the electrolytic solution to be supplied to the cathode 47, thereby reducing the amount of water used in the electrolysis device 1.

[0102] (14) The electrolysis device 1 of a fourteenth aspect is any one of the electrolysis devices 1 of (11) to (13), in which the second separator 42 has an outlet 90 through which oxygen and water are discharged. The electrolysis device 1 further includes a suction device 95 connected to the outlet 90 and configured to suck oxygen and water toward the outside of the electrolysis cell 11C. With this configuration, when oxygen and water are discharged from the second separator 42 through the outlet 90, the suction device 95 sucks the oxygen and water toward the outside of the electrolysis cell 11C. This allows oxygen and water to be efficiently discharged while suppressing a pressure increase within the electrolysis cell 11C.

[0103] (15) The electrolysis cell 11 of the fifteenth embodiment includes a first separator 41, a second separator 42, an ion exchange membrane 51 disposed between the first separator 41 and the second separator 42, a cathode 47 disposed between the first separator 41 and the ion exchange membrane 51, and an anode 48 disposed between the second separator 42 and the ion exchange membrane 51. The first separator 41 has a first flow path 41r1 for supplying an electrolytic solution to the cathode 47, and the second separator 42 does not have a flow path for supplying an electrolytic solution to the anode 48. The second separator has a gas outlet 42g through which gas generated at the anode 48 is mainly discharged, and a liquid outlet 42h through which liquid generated at the anode 48 is mainly discharged. The gas outlet 42g and the liquid outlet 42h are provided separately in the second separator 42. According to this configuration, the gas outlet 42g and the liquid outlet 42h are separately provided in the second separator 42. As a result, oxygen and water generated on the anode 48 side are discharged separately from the gas outlet 42g and the liquid outlet 42h. This allows oxygen and water to be smoothly discharged from within the electrolysis cell 11. This improves electrolysis performance compared to a case in which oxygen and water are discharged in a mixed state from within the electrolysis cell 11, and reduces the need to provide a gas-liquid separator for separating oxygen and water outside the electrolysis cell 11, leading to cost reduction. [Explanation of symbols]

[0104] 1...Electrolyzer 11, 11A, 11B, 11C...Electrolytic cell 20...Electrolyte supply section 27…Ion exchange resin tank 29...Oxygen gas-liquid separation section (gas-liquid separation section) 30...Power supply section 41…First separator 41a…First inner surface 41r1…First flow path 41r2…Second flow path 42…Second separator 42a…Second inner surface 42g…Gas outlet 42h…Liquid outlet 47...Cathode 48...Anode 51...Ion exchange membrane (anion exchange membrane) 51a…First page 51b…Second side 52...Cathode catalyst layer 53...Cathode power supply 54...Anode catalyst layer 55...Anode current collector 90…Discharge port 95...Suction device WS…Water surface

Claims

1. A first separator; A second separator; an anion exchange membrane disposed between the first separator and the second separator; a cathode disposed between the first separator and the anion exchange membrane; an anode disposed between the second separator and the anion exchange membrane; Equipped with the first separator has a flow path for supplying an electrolytic solution to the cathode, and at least a portion of the electrolytic solution supplied from the flow path is consumed in the cathode to generate hydrogen and hydroxide ions; the second separator does not have a flow path for supplying the electrolytic solution to the anode, and oxygen and water are generated at the anode by the hydroxide ions that have passed through the anion exchange membrane from the cathode in a state in which the electrolytic solution is not supplied, The second separator has a gas discharge port through which the oxygen is mainly discharged and a liquid discharge port through which the water is mainly discharged, and the gas discharge port and the liquid discharge port are separately provided on the second separator. Electrolysis cell.

2. The liquid outlet is provided below the gas outlet.

2. The electrolysis cell of claim 1.

3. an anode chamber is defined between the second separator and the anion exchange membrane; the gas exhaust port is provided above the vertical center of the anode chamber, The liquid outlet is provided below the vertical center of the anode chamber.

2. The electrolysis cell of claim 1.

4. A first separator; A second separator; an anion exchange membrane disposed between the first separator and the second separator; a cathode disposed between the first separator and the anion exchange membrane; an anode disposed between the second separator and the anion exchange membrane; Equipped with the first separator has a flow path for supplying an electrolytic solution to the cathode, and at least a portion of the electrolytic solution supplied from the flow path is consumed in the cathode to generate hydrogen and hydroxide ions; the second separator does not have a flow path for supplying the electrolytic solution to the anode, and oxygen and water are generated at the anode by the hydroxide ions that have passed through the anion exchange membrane from the cathode in a state in which the electrolytic solution is not supplied, an anode chamber is defined between the second separator and the anion exchange membrane; the second separator has an outlet through which the oxygen and the water are discharged, the discharge port is formed such that an upper end of the discharge port is located above the water level of the water accumulated in the anode chamber in a steady operation state of the electrolytic cell. Electrolysis cell.

5. A first separator; A second separator; an anion exchange membrane disposed between the first separator and the second separator; a cathode disposed between the first separator and the anion exchange membrane; an anode disposed between the second separator and the anion exchange membrane; Equipped with the first separator has a flow path for supplying an electrolytic solution to the cathode, and at least a portion of the electrolytic solution supplied from the flow path is consumed in the cathode to generate hydrogen and hydroxide ions; the second separator does not have a flow path for supplying the electrolytic solution to the anode, and oxygen and water are generated at the anode by the hydroxide ions that have passed through the anion exchange membrane from the cathode in a state in which the electrolytic solution is not supplied, an anode chamber is defined between the second separator and the anion exchange membrane; the second separator has an outlet through which the oxygen and the water are discharged, The exhaust port is provided at the vertical center of the anode chamber or below the vertical center. Electrolysis cell.

6. A first separator; A second separator; an anion exchange membrane disposed between the first separator and the second separator; a cathode disposed between the first separator and the anion exchange membrane; an anode disposed between the second separator and the anion exchange membrane; Equipped with the first separator has a flow path for supplying an electrolytic solution to the cathode, and at least a portion of the electrolytic solution supplied from the flow path is consumed in the cathode to generate hydrogen and hydroxide ions; the second separator does not have a flow path for supplying the electrolytic solution to the anode, and oxygen and water are generated at the anode by the hydroxide ions that have passed through the anion exchange membrane from the cathode in a state in which the electrolytic solution is not supplied, the cathode is disposed between the first separator and the anion exchange membrane and includes a cathode current collector which is a mesh structure, a porous body, or a fiber; the anode is disposed between the second separator and the anion exchange membrane and includes an anode current collector which is a mesh structure, a porous body, or a fiber; The average size of the holes in the anode current collector is larger than the average size of the holes in the cathode current collector. Electrolysis cell.

7. A first separator; A second separator; an anion exchange membrane disposed between the first separator and the second separator; a cathode disposed between the first separator and the anion exchange membrane; an anode disposed between the second separator and the anion exchange membrane; Equipped with the first separator has a flow path for supplying an electrolytic solution to the cathode, and at least a portion of the electrolytic solution supplied from the flow path is consumed in the cathode to generate hydrogen and hydroxide ions; the second separator does not have a flow path for supplying the electrolytic solution to the anode, and oxygen and water are generated at the anode by the hydroxide ions that have passed through the anion exchange membrane from the cathode in a state in which the electrolytic solution is not supplied, the cathode is disposed between the first separator and the anion exchange membrane and includes a cathode current collector which is a mesh structure, a porous body, or a fiber; the anode is disposed between the second separator and the anion exchange membrane and includes an anode current collector which is a mesh structure, a porous body, or a fiber; The porosity of the anode current collector is greater than the porosity of the cathode current collector. Electrolysis cell.

8. A first separator; A second separator; an anion exchange membrane disposed between the first separator and the second separator; a cathode disposed between the first separator and the anion exchange membrane; an anode disposed between the second separator and the anion exchange membrane; Equipped with the first separator has a flow path for supplying an electrolytic solution to the cathode, and at least a portion of the electrolytic solution supplied from the flow path is consumed in the cathode to generate hydrogen and hydroxide ions; the second separator does not have a flow path for supplying the electrolytic solution to the anode, and oxygen and water are generated at the anode by the hydroxide ions that have passed through the anion exchange membrane from the cathode in a state in which the electrolytic solution is not supplied, the cathode is disposed between the first separator and the anion exchange membrane and includes a cathode current collector which is a mesh structure, a porous body, or a fiber; the anode is disposed between the second separator and the anion exchange membrane and includes an anode current collector which is a mesh structure, a porous body, or a fiber; In a stacking direction in which the first separator and the second separator overlap, a thickness of the anode current collector is smaller than a thickness of the cathode current collector. Electrolysis cell.

9. A first separator; A second separator; an anion exchange membrane disposed between the first separator and the second separator; a cathode disposed between the first separator and the anion exchange membrane; an anode disposed between the second separator and the anion exchange membrane; Equipped with the first separator has a flow path for supplying an electrolytic solution to the cathode, and at least a portion of the electrolytic solution supplied from the flow path is consumed in the cathode to generate hydrogen and hydroxide ions; the second separator does not have a flow path for supplying the electrolytic solution to the anode, and oxygen and water are generated at the anode by the hydroxide ions that have passed through the anion exchange membrane from the cathode in a state in which the electrolytic solution is not supplied, the first separator has a first surface facing the second separator, the first surface includes a first region having a plurality of grooves through which the electrolyte flows; the second separator has a second surface facing the first separator, the second surface has a second region facing the first region, The second region is formed in a planar shape. Electrolysis cell.

10. An electrolysis cell according to any one of claims 1 to 9; an electrolyte supply unit that supplies the electrolyte to the electrolytic cell; A power supply unit that applies a voltage to the electrolytic cell; An electrolysis device comprising:

11. An electrolysis apparatus comprising: An electrolysis cell; an electrolyte supply unit for supplying an electrolyte to the electrolytic cell; A power supply unit that applies a voltage to the electrolytic cell; Equipped with The electrolysis cell comprises: A first separator; A second separator; an anion exchange membrane disposed between the first separator and the second separator; a cathode disposed between the first separator and the anion exchange membrane; an anode disposed between the second separator and the anion exchange membrane; Equipped with the first separator has a flow path for supplying the electrolytic solution to the cathode, and at least a portion of the electrolytic solution supplied from the flow path is consumed in the cathode to generate hydrogen and hydroxide ions; the second separator does not have a flow path for supplying the electrolytic solution to the anode, and oxygen and water are generated at the anode by the hydroxide ions that have passed through the anion exchange membrane from the cathode in a state in which the electrolytic solution is not supplied, the second separator has a gas discharge port through which gas produced at the anode is mainly discharged, and a liquid discharge port through which liquid produced at the anode is mainly discharged, the gas discharge port and the liquid discharge port being separately provided on the second separator, The electrolysis device comprises: The liquid discharged from the liquid discharge port is separated from the gas contained in the liquid, and the separated gas is merged with the gas discharged from the gas discharge port. Electrolyzer.

12. an ion exchange resin tank into which the water discharged from the second separator flows and which removes at least a portion of the ions contained in the water; a piping line for guiding the water that has passed through the ion exchange resin tank so as to join the electrolytic solution to be supplied to the cathode; Further equipped with 11. The electrolysis device according to claim 10.

13. the second separator has an outlet through which the oxygen and the water are discharged, The electrolysis device comprises: The electrolysis cell further includes a suction device connected to the outlet and configured to suck the oxygen and the water out of the electrolysis cell.

11. The electrolysis device according to claim 10.

Images