Membrane electrode assembly and method for manufacturing membrane electrode assembly

Abstract

To provide a membrane electrode joint that can suppress non-uniformity of contact resistance (variation within a plane) and local current concentration, and a manufacturing method for membrane electrode joint.SOLUTION: A membrane electrode joint comprises an ion-exchange membrane having a first face and a second face opposite the first face, and a cathode catalyst layer disposed further to the first face side than the ion-exchange membrane, an anode catalyst layer disposed further to the second face side than the ion-exchange membrane, and an ionomer layer provided separately from the cathode catalyst layer and the anode catalyst layer between the ion-exchange membrane and the cathode catalyst layer and between the ion-exchange membrane and the anode catalyst layer and forming a layer structure together with the anode catalyst layer.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a membrane electrode assembly and a method for manufacturing a membrane electrode assembly. [Background technology]

[0002] Patent Document 1 discloses a membrane electrode assembly (MEA) in which two electrodes, each composed of an electrode substrate and an electrode catalyst layer, are prepared and a proton exchange membrane (ion exchange membrane) is disposed between the two electrodes. In the membrane electrode assembly, the electrode catalyst layer side of each electrode is disposed facing the proton exchange membrane, and the two electrodes are joined together in a state in which the proton exchange membrane is sandwiched between them. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4734688 Summary of the Invention [Problem to be solved by the invention]

[0004] When an electrode catalyst layer is formed by coating or the like, the surface of the electrode catalyst layer bonded to the proton exchange membrane may be rough. In this case, due to the surface roughness of the electrode catalyst layer, the membrane-electrode assembly may have sparse areas where the electrode catalyst layer is in close contact with the proton exchange membrane and areas where it is not in close contact. As a result, contact resistance concentrates in the areas where the electrode catalyst layer is in close contact, resulting in localized areas with high current density, which poses a durability issue for the water electrolysis device.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a membrane electrode assembly in which a catalyst layer and an anion exchange membrane are closely attached to each other, eliminating variations in ion conductivity and forming a uniform electrolytic surface, thereby enabling the construction of a durable membrane electrode assembly and suppressing the concentration of contact resistance, as well as a method for manufacturing the membrane electrode assembly. [Means for solving the problem]

[0006] In order to solve the above-described problems, the membrane electrode assembly according to the present disclosure includes: an ion exchange membrane having a first surface and a second surface located opposite to the first surface; a cathode catalyst layer disposed closer to the first surface than the ion exchange membrane; an anode catalyst layer disposed closer to the second surface than the ion exchange membrane; and ionomer layers provided between the ion exchange membrane and the cathode catalyst layer and between the ion exchange membrane and the anode catalyst layer as separate entities from the cathode catalyst layer and the anode catalyst layer, and forming a layer structure together with the cathode catalyst layer and the anode catalyst layer.

[0007] The method for manufacturing a membrane electrode assembly according to the present disclosure includes the steps of providing an ionomer layer separate from the cathode catalyst layer and the anode catalyst layer on each of a cathode catalyst layer formed on one side of a cathode current collector and an anode catalyst layer formed on one side of an anode current collector, and overlaying the ionomer layer provided on the cathode catalyst layer on a first side of an ion exchange membrane, and overlaying the ionomer layer provided on the anode catalyst layer on a second side of the ion exchange membrane opposite to the first side, and hot or cold pressing the resulting mixture to form a layer structure.

[0008] The method for manufacturing a membrane electrode assembly according to the present disclosure includes the steps of providing an ionomer layer on each of a first surface of an ion exchange membrane and a second surface opposite the first surface, and overlaying a cathode catalyst layer provided on one surface of a cathode current collector on the ionomer layer provided on the first surface of the ion exchange membrane so as to be separate from the ionomer layer, and overlaying an anode catalyst layer provided on one surface of an anode current collector on the ionomer layer provided on the second surface of the ion exchange membrane so as to be separate from the ionomer layer, and hot or cold pressing the resulting mixture to form a layer structure. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to provide a membrane electrode assembly capable of suppressing the concentration of contact resistance, and a method for manufacturing the membrane electrode assembly. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram showing the overall configuration of an electrolysis device according to a first embodiment of the present disclosure. FIG. [Figure 2] FIG. 1 is a diagram schematically illustrating an electrolysis cell according to a first embodiment of the present disclosure. [Figure 3] FIG. 1 is an exploded perspective view showing an electrolysis cell according to a first embodiment of the present disclosure. [Figure 4] FIG. 1 is a cross-sectional view showing an electrolysis cell according to a first embodiment of the present disclosure. [Figure 5] 1A to 1C are cross-sectional views illustrating a method for manufacturing a membrane electrode assembly according to a first embodiment of the present disclosure. [Figure 6] 4A to 4C are cross-sectional views showing a method for manufacturing a membrane electrode assembly according to a second embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] An electrolysis device 1 according to an embodiment of the present disclosure and a method for manufacturing a membrane electrode assembly 43 for the electrolysis device 1 will be described below with reference to the drawings. In the following description, components having the same or similar functions will be denoted by the same reference numerals. In this specification, "facing" means that two components overlap when viewed in a certain direction, and may also include the case where another component (e.g., another layer) exists between the two components.

[0012] First, referring to FIG. 4, the Z direction, X direction, and Y direction are defined. The Z direction is the direction from a first separator 41 to a second separator 42 (the left-right direction in FIG. 4), which will be described later. The Z direction is also the stacking direction when an ion exchange membrane 50, an ionomer layer 51, a cathode catalyst layer 54, and an anode catalyst layer 56 of a membrane electrode assembly 43 (which will be described later) form a layered structure. The X direction is a direction intersecting (e.g., perpendicular to) the Z direction and is a direction from a center C of the membrane electrode assembly 43 to one end of the membrane electrode assembly 43 (the up-down direction in FIG. 4). The Y direction is a direction intersecting (e.g., perpendicular to) the Z direction and the X direction and is, for example, the depth direction of the paper in FIG. 4. In this specification, the term "area" refers to the area when viewed in the Z direction (i.e., the area extending in the X and Y directions). In this specification, the term "external size" refers to the external size when viewed in the Z direction. That is, "external size" and "area" may mean substantially the same thing and may be interpreted interchangeably as appropriate.

[0013] First Embodiment (Configuration of electrolysis device) FIG. 1 is a schematic diagram showing the overall configuration of an electrolysis device 1 according to a first embodiment. The electrolysis device 1 is, for example, a device that generates hydrogen by electrolyzing water contained in an electrolyte solution. The electrolysis device 1 is, for example, an anion exchange membrane (AEM) type electrolysis device. However, the electrolysis device 1 is not limited to the above example, and may be a different type of electrolysis device, such as a proton exchange membrane (PEM) type electrolysis device or a device that electrolytically reduces carbon dioxide.

[0014] The electrolysis device 1 includes, for example, an electrolysis cell stack 10, an electrolyte supply unit 20, and a power supply unit 30.

[0015] (Electrolysis cell stack) The electrolytic cell stack 10 is an assembly of multiple electrolytic cells 11. For example, the electrolytic cell stack 10 is formed by arranging multiple electrolytic cells 11 in one direction. Each electrolytic cell 11 includes a cathode chamber Sa and an anode chamber Sb. The electrolytic 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. The electrolyte supply unit 20 includes a cathode side supply unit 20a and an anode side supply unit 20b.

[0017] The cathode-side supply unit 20a is a supply unit that supplies the electrolytic solution to the cathode chamber Sa of each electrolytic cell 11. The cathode-side supply unit 20a includes, for example, a hydrogen gas-liquid separator 21, a first pump 22, a hydrogen recovery unit 23, a first electrolytic solution supply unit 24, and piping lines L1 and L2.

[0018] The hydrogen-gas-liquid separator 21 stores the electrolytic solution. A supply port of the hydrogen-gas-liquid separator 21 is connected to the cathode chamber Sa of the electrolytic cell 11 via a piping line L1. A first pump 22 is provided midway along the piping line L1 and sends the electrolytic solution stored in the hydrogen-gas-liquid separator 21 toward the cathode chamber Sa of the electrolytic cell 11.

[0019] A return port of the hydrogen-gas-liquid separator 21 is connected to the cathode chamber Sa of the electrolytic cell 11 via a piping line L2. An electrolytic solution containing hydrogen produced in the electrolytic cell 11 flows into the hydrogen-gas-liquid separator 21 from the electrolytic cell 11. The hydrogen-gas-liquid separator 21 has a gas-liquid separation unit that separates the hydrogen contained in the electrolytic solution. The hydrogen separated from the electrolytic solution by the hydrogen-gas-liquid separator 21 is recovered by a hydrogen recovery unit 23. The hydrogen-gas-liquid separator 21 is replenished with electrolytic solution from a first electrolytic solution supply unit 24.

[0020] On the other hand, the anode-side supply unit 20b is a supply unit that supplies the electrolytic solution to the anode chamber Sb of each electrolytic cell 11. The anode-side supply unit 20b includes, for example, an oxygen gas-liquid separator 26, a second pump 27, an oxygen recovery unit 28, a second electrolytic solution supply unit 29, and piping lines L3 and L4.

[0021] The oxygen-gas-liquid separator 26 stores the electrolyte. A supply port of the oxygen-gas-liquid separator 26 is connected to the anode chamber Sb of the electrolytic cell 11 via a piping line L3. A second pump 27 is provided in the piping line L3 and sends the electrolyte stored in the oxygen-gas-liquid separator 26 toward the anode chamber Sb of the electrolytic cell 11.

[0022] A return port of the oxygen-gas-liquid separator 26 is connected to the anode chamber Sb of the electrolytic cell 11 via a piping line L4. The electrolyte containing oxygen produced in the electrolytic cell 11 flows from the electrolytic cell 11 into the oxygen-gas-liquid separator 26. The oxygen-gas-liquid separator 26 has a gas-liquid separation unit that separates the oxygen contained in the electrolyte. The oxygen separated from the electrolyte by the oxygen-gas-liquid separator 26 is recovered by an oxygen recovery unit 28. The oxygen-gas-liquid separator 26 is replenished with electrolyte from a second electrolyte supply unit 29.

[0023] (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.

[0024] (Electrolytic cell configuration) Next, the electrolytic cell 11 will be described in detail. 2 is a cross-sectional view schematically illustrating the electrolysis cell 11. The electrolysis cell 11 includes, for example, a first separator 41, a second separator 42, and a membrane electrode assembly 43.

[0025] (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, which will be described later. The first separator 41 is, for example, a rectangular plate, and is formed of a metal member such as stainless steel, titanium, or nickel, a conductive carbon plate, or a conductive carbon plate sealed with a molded resin. A negative voltage is applied to the first separator 41 from the power supply unit 30, for example, via a first current collector 61 (see FIG. 3), which will be described later.

[0026] The first separator 41 has a first separator end 41e1 (e.g., a lower end) and a second separator end 41e2 (e.g., an upper end) located opposite the first separator end 41e1. The above-mentioned piping line L1 is connected to the first separator end 41e1 of the first separator 41. The above-mentioned piping line L2 is connected to the second separator end 41e2 of the first separator 41. The first separator 41 has a first inner surface 41a facing the cathode chamber Sa described below. The first inner surface 41a is formed with a first flow path FP1 through which the electrolytic solution supplied from the piping line L1 flows. The first flow path FP1 is, for example, a groove provided in the first inner surface 41a. The electrolytic solution that has flowed through the first flow path FP1 is discharged to the outside of the electrolytic cell 11 through the piping line L2. Note that the structures (e.g., flow path structure) shown in FIG. 2 are merely examples and do not limit the content of this embodiment. For example, various flow channel structures can be used depending on the size and purpose of the device, the environment in which it is used, etc. This also applies to the structures shown in the other figures.

[0027] (Second separator) The second separator 42 is disposed with an internal space S between it and at least a portion 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, a rectangular plate and is made of a metal member such as stainless steel, titanium, or nickel. A positive voltage is applied to the second separator 42 from the power supply unit 30 via a second current collector 62 (see FIG. 3 ), which will be described later. The first separator 41 and the second separator 42 included in the same electrolytic cell 11 form an electrolytic cell 40 of the electrolytic cell 11 as a pair of separators.

[0028] The second separator 42 has a first separator end 42e1 (e.g., a lower end) and a second separator end 42e2 (e.g., an upper end) located opposite the first separator end 42e1. The above-mentioned piping line L3 is connected to the first separator end 42e1 of the second separator 42. The above-mentioned piping line L4 is connected to the second separator end 42e2 of the second separator 42. The second separator 42 has a second inner surface 42a facing the anode chamber Sb, which will be described later. A second flow path FP2 is formed in the second inner surface 42a, through which the electrolytic solution supplied from the piping line L3 flows. The second flow path FP2 is, for example, a groove provided in the second inner surface 42a. The electrolytic solution that has flowed through the second flow path FP2 is discharged to the outside of the electrolytic cell 11 through the piping line L4.

[0029] For ease of explanation, the first separator 41 has a first inner surface 41a with a flow path groove (first flow path FP1), and the second separator 42 has a second inner surface 42a with a flow path groove (second flow path FP2). However, for example, the first separator 41 of the electrolysis cell 11 included in the electrolysis cell stack 10 (see FIG. 1 ) may be a bipolar plate having a similar flow path groove (first flow path FP1, shown by a two-dot chain line in FIG. 2 ) on the surface 41b opposite the first inner surface 41a in addition to the first inner surface 41a. The second separator 42 of the electrolysis cell 11 included in the electrolysis cell stack 10 may be a bipolar plate having a similar flow path groove (second flow path FP2, shown by a two-dot chain line in FIG. 2 ) on the surface 42b opposite the second inner surface 42a in addition to the second inner surface 42a. The flow path grooves provided on both surfaces of the first separator 41 may have different shapes and arrangements. Furthermore, the flow path grooves provided on both sides of the second separator 42 may have different shapes and arrangements.

[0030] (Configuration of 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 a first separator 41 and a second separator 42, and is located in an internal space S. The membrane electrode assembly 43 includes, for example, an ion exchange membrane 50, an ionomer layer 51, a cathode catalyst layer 54, a cathode power supply 55, an anode catalyst layer 56, and an anode power supply 57.

[0031] (ion exchange membrane) The ion exchange membrane 50 is a membrane that selectively allows ions to pass through. The ion exchange membrane 50 is, for example, a solid polymer electrolyte membrane. The ion exchange membrane 50 is, for example, an anion exchange membrane (AEM) that is hydroxide ion conductive. However, the ion exchange membrane 50 is not limited to the above example and may be an ion exchange membrane of a type different from the above example, such as a proton exchange membrane (PEM: Polymer Electrolyte Membrane). The ion exchange membrane 50 is, for example, in the form of a rectangular sheet. The outer size of the ion exchange membrane 50 is smaller than the outer size of the first separator 41 or the second separator 42. The ion exchange membrane 50 is disposed between the first separator 41 and the second separator 42 and is located in the internal space S described above. The ion exchange membrane 50 has a first surface 50a facing the first inner surface 41a of the first separator 41 and a second surface 50b located on the opposite side to the first surface 50a. The second surface 50b of the ion exchange membrane 50 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 50a of the ion exchange membrane 50 and the first inner surface 41a of the first separator 41. In addition, in the internal space S, an anode chamber Sb is defined between the second surface 50b of the ion exchange membrane 50 and the second inner surface 42a of the second separator 42.

[0032] When a voltage is applied to the electrolytic cell 11, the chemical reaction shown in Chemical Formula 1 below occurs in the cathode chamber Sa, and hydrogen is produced from the electrolytic solution. In this specification, the phrase "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 membrane electrode assembly 43 and move from the cathode chamber Sa to the anode chamber Sb. 2H2O+2e - →H2+2OH - …(C1)

[0033] In the anode chamber Sb, when a voltage is applied to the electrolytic cell 11, the chemical reaction shown in the following (chemical formula 2) occurs, and oxygen is produced from the electrolytic solution. 2OH - →1 / 2O2+H2O+2e - …(Case 2)

[0034] As a result, when viewed as a whole in the electrolysis cell 11, the chemical reaction shown in Chemical Formula 3 below occurs. H2O→H2+1 / 2O2…(Chem.3)

[0035] The ion exchange membrane 50 may have a high ion conductivity and may contain a polystyrene-based or tetraphenyl-based composition in the main chain and an imidazolium group or a quaternary ammonium group in the side chain. Alternatively, the ion exchange membrane 50 may have a high oxidation resistance and may contain a polysulfone-based or bromobutylstyrene-based composition.

[0036] (Ionomer layer) The ionomer layer 51 is a layer provided on the ion exchange membrane 50. The ionomer layer 51 is a layer through which hydroxide ions can pass. The ionomer layer 51 has, for example, a rectangular sheet shape. In this embodiment, the outer diameter of the ionomer layer 51 is smaller than the outer diameter of the ion exchange membrane 50. The thickness of the ionomer layer 51 is, for example, 1 nm or more and 10 μm or less.

[0037] In this embodiment, the ionomer layer 51 is composed of an ionomer resin component and a non-ionomer resin component different from the ionomer resin component. The ionomer resin component includes, for example, diaza(bicyclooctane) polyethersulfone, poly[(p-terphenyl-4,4'-diyl)(N,N-dimethyl-piperidinium-bicarbonate-4,4-diyl)-co-(p-terphenyl-4,4'-diyl)(2,2,2-trifluoro-1-phenylethylidene-diyl)], or poly[(p-terphenyl-4,4'-diyl)(N,N-dimethyl-piperidinium-bicarbonate-4,4-diyl)]. In this embodiment, the ionomer resin component may contain additives, for example, because a specific polymer compound is added during production. The ionomer resin component is contained in the ionomer layer 51 at a ratio of 80% by mass or more but less than 100% by mass. The non-ionomer resin component includes electrocatalyst particles and a binder. The cathode catalyst particles include, for example, one or more of nickel, nickel alloy, cerium oxide, lanthanum oxide, or platinum. In this disclosure, "XX oxide" may include other materials in addition to XX and oxygen. The anode catalyst includes one or more of nickel, nickel alloy, nickel oxide, copper oxide, iridium oxide, niobium oxide, lead oxide, or bismuth oxide. As described above, in this disclosure, "XX oxide" may include other materials in addition to XX and oxygen. For anode catalyst particles, "nickel oxide" may contain other materials such as iron and cobalt in addition to nickel and oxygen. "Copper oxide" may contain other materials such as cobalt in addition to copper and oxygen. "Iridium oxide" may contain other materials such as ruthenium in addition to iridium and oxygen. "Lead oxide" may contain other materials such as ruthenium in addition to lead and oxygen. "Bismuth oxide" may contain other materials such as ruthenium in addition to bismuth and oxygen. Fluorine-based binders such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and tetrafluoroethylene-ethylene copolymer (ETFE) are used as binders.

[0038] The ionomer layer 51 is provided, for example, on the entire first surface 50a and the entire second surface 50b of the ion exchange membrane 50. Hereinafter, for convenience of explanation, the ionomer layer 51 provided on the first surface 50a of the ion exchange membrane 50 will be referred to as the "first ionomer layer 52," and the ionomer layer 51 provided on the second surface 50b of the ion exchange membrane 50 will be referred to as the "second ionomer layer 53." In this embodiment, the outer diameter of the first ionomer layer 52 is the same as the outer diameter of the second ionomer layer 53. Furthermore, the thickness of the first ionomer layer 52 is the same as the thickness of the second ionomer layer 53. The first ionomer layer 52 is disposed in the cathode chamber Sa and is bonded to the first surface 50a of the ion exchange membrane 50. The second ionomer layer 53 is disposed in the anode chamber Sb and is bonded to the second surface 50b of the ion exchange membrane 50.

[0039] (Cathode catalyst layer) The cathode catalyst layer 54 is a layer that promotes the chemical reaction in the cathode chamber Sa described above. The cathode catalyst layer 54 is, for example, in the form of a rectangular sheet. In this embodiment, the cathode catalyst layer 54 is formed to have an outer size that is, for example, the same as that of the first ionomer layer 52. The cathode catalyst layer 54 is disposed in the cathode chamber Sa and is provided over the entire area of ​​the first ionomer layer 52. A negative voltage is applied to the cathode catalyst layer 54 from the power supply unit 30 via the first separator 41 and the cathode power supply 55, and the cathode catalyst layer 54 functions as part of the cathode 47 of the electrolysis cell 11.

[0040] The cathode catalyst layer 54 may be made of any material that promotes the chemical reaction in the cathode chamber Sa. For example, the cathode catalyst layer 54 may contain one or more of nickel, nickel alloy, cerium oxide, lanthanum oxide, or platinum. Note that the "XX oxide" in this specification may include materials other than XX and oxygen. The cathode catalyst layer 54 is formed by adding the additives described above during manufacturing. In other words, the cathode catalyst layer 54 contains the additives described above. The cathode catalyst layer 54 may contain other materials, such as carbon, in addition to the materials described above.

[0041] (Cathode feeder) The cathode current collector 55 is an electrical connection part that transmits the voltage applied to the first separator 41 to the cathode catalyst layer 54. The cathode current collector 55 is disposed in the cathode chamber Sa. The cathode current collector 55 is located between the first inner surface 41a of the first separator 41 and the cathode catalyst layer 54, and is bonded to both the first inner surface 41a of the first separator 41 and the cathode catalyst layer 54. The cathode catalyst layer 54 is formed on the surface of the cathode current collector 55 that faces the ion exchange membrane 50. Hereinafter, the surface of the cathode current collector 55 on which the cathode catalyst layer 54 is formed is referred to as the "cathode surface 55a." The cathode surface 55a is an example of one surface of the cathode current collector 55. At least a portion of the cathode current collector 55 may overlap at least a portion of at least one of the first separator 41 or the cathode catalyst layer 54. The cathode current collector 55 has a structure that allows the electrolyte and gas to pass through it. The cathode current collector 55 is formed, for example, of a metal mesh structure, a sintered body, a mesh structure of fiber or conductive carbon fiber, or a nonwoven fabric. In this embodiment, the external size of the cathode current collector 55 is the same as the external size of the cathode catalyst layer 54. In this embodiment, the cathode catalyst layer 54 and the cathode current collector 55 form the cathode 47 of the electrolysis cell 11.

[0042] (Anode catalyst layer) The anode catalyst layer 56 is a layer that promotes the chemical reaction in the anode chamber Sb described above. The anode catalyst layer 56 is, for example, in the form of a rectangular sheet. In this embodiment, the external size of the anode catalyst layer 56 is formed to be the same as that of the second ionomer layer 53. The anode catalyst layer 56 is disposed in the anode chamber Sb and is provided over the entire area of ​​the second ionomer layer 53. A positive voltage is applied to the anode catalyst layer 56 from the power supply unit 30 via the second separator 42 and the anode power supply 57, and the anode catalyst layer 56 functions as part of the anode 48 of the electrolysis cell 11. In this embodiment, the anode catalyst layer 56 is formed to be the same thickness as the cathode catalyst layer 54.

[0043] The anode catalyst layer 56 may be made of any material that promotes the chemical reaction in the anode chamber Sb. For example, the anode catalyst layer 56 may contain one or more of nickel, nickel alloy, nickel oxide, copper oxide, iridium oxide, niobium oxide, lead oxide, or bismuth oxide. As described above, the term "XX oxide" in this specification may include other materials in addition to XX and oxygen. For example, "nickel oxide" may include other materials such as iron or cobalt in addition to nickel and oxygen. "Copper oxide" may include other materials such as cobalt in addition to copper and oxygen. "Iridium oxide" may include other materials such as ruthenium in addition to iridium and oxygen. "Lead oxide" may include other materials such as ruthenium in addition to lead and oxygen. "Bismuth oxide" may include other materials such as ruthenium in addition to bismuth and oxygen. The anode catalyst layer 56 is formed by adding the above-mentioned additives during manufacturing. That is, the anode catalyst layer 56 contains the above-mentioned additives.

[0044] Therefore, the above-mentioned ionomer layer 51 (first ionomer layer 52 and second ionomer layer 53) is provided between the ion exchange membrane 50 and the cathode catalyst layer 54, and between the ion exchange membrane 50 and the anode catalyst layer 56, as a separate body from the cathode catalyst layer 54 and the anode catalyst layer 56, and forms a layer structure together with the ion exchange membrane 50, the cathode catalyst layer 54, and the anode catalyst layer 56. That is, an interface exists between the first ionomer layer 52 and the cathode catalyst layer 54, and between the second ionomer layer 53 and the anode catalyst layer 56. In addition, an interface exists between the first ionomer layer 52 and the ion exchange membrane 50, and between the second ionomer layer 53 and the ion exchange membrane 50. In this embodiment, the thickness of the ionomer layer 51 (first ionomer layer 52 and second ionomer layer 53) is 10% to 50% of the thickness of the cathode catalyst layer 54 and the thickness of the anode catalyst layer 56. The thickness of the first ionomer layer 52 is 10% to 50% of the thickness of the cathode catalyst layer 54, and the thickness of the second ionomer layer 53 is 10% to 50% of the thickness of the anode catalyst layer 56.

[0045] (anode current collector) The anode current collector 57 is an electrical connection part that transmits the voltage applied to the second separator 42 to the anode catalyst layer 56. The anode current collector 57 is disposed in the anode chamber Sb. The anode current collector 57 is located between the second inner surface 42a of the second separator 42 and the anode catalyst layer 56, and is bonded to both the second inner surface 42a of the second separator 42 and the anode catalyst layer 56. The anode catalyst layer 56 is formed on the surface of the anode current collector 57 that faces the ion exchange membrane 50. Hereinafter, the surface of the anode current collector 57 on which the anode catalyst layer 56 is formed is referred to as the "anode surface 57a." The anode surface 57a is an example of one surface of the anode current collector 57. At least a portion of the anode current collector 57 may overlap at least a portion of at least one of the second separator 42 or the anode catalyst layer 56. The anode current collector 57 has a structure that allows the electrolyte and gas to pass through it. The anode current collector 57 is formed, for example, of a metal mesh structure, a sintered body, or fiber. In this embodiment, the external size of the anode current collector 57 is the same as the external size of the anode catalyst layer 56. In this embodiment, the anode catalyst layer 56 and the anode current collector 57 form the anode 48 of the electrolysis cell 11.

[0046] Figure 3 is an exploded perspective view of the electrolytic cell 11. In addition to the components described above, the electrolytic 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 insulating material 65, a second insulating material 66, a first end plate 67, and a second end plate 68. For ease of explanation, a support member 70 and a sealing member 80, which will be described later, are not shown in Figure 3.

[0047] (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 electrolysis cell 11, for example, and is electrically connected to the first separator 41. A negative voltage required for electrolysis in the electrolysis 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 two electrolysis cells 11 that are adjacent to each other in the electrolysis cell stack 10.

[0048] (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 electrolysis cell 11, for example, and is electrically connected to the second separator 42. A positive voltage required for electrolysis in the electrolysis 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 two electrolysis cells 11 that are adjacent to each other in the electrolysis cell stack 10.

[0049] (first insulator) The first insulator 63 is a member that provides insulation between the outer periphery of the first separator 41 and the outer periphery of the second separator 42. The first insulator 63 is a frame-shaped sheet member that is slightly larger than the outer shape of the cathode catalyst layer 54 and the outer shape of the cathode power supplier 55. The first insulator 63 is attached to the first inner surface 41a of the first separator 41 and covers the end of the first inner surface 41a. The material of the first insulator 63 is not particularly limited as long as it is an insulating material, and is, for example, a sheet-shaped resin such as PTFE (polytetrafluoroethylene).

[0050] (second insulator) The second insulator 64, like the first insulator 63, is a member that provides insulation between the outer periphery of the first separator 41 and the outer periphery of the second separator 42. The second insulator 64 is a frame-shaped sheet member that is slightly larger than the outer shape of the anode catalyst layer 56 and the outer shape of the anode power supply 57. The second insulator 64 is attached to the second inner surface 42a of the second separator 42 and covers the end of the second inner surface 42a. The material of the second insulator 64 is not particularly limited as long as it is an insulating material, and is, for example, a sheet-shaped resin such as PTFE. The first insulator 63 and the second insulator 64 can also be used as an integrated insulator.

[0051] (First Insulation Material) The first insulator 65 is located between the first current collector 61 and the first end plate 67. The outer size of the first insulator 65 is, for example, the same as or larger than the outer size of the first current collector 61.

[0052] (Second insulating material) The second insulator 66 is located between the second current collector 62 and the second end plate 68. The outer size of the second insulator 66 is, for example, the same as or larger than the outer size of the second current collector 62.

[0053] (First end plate) The first end plate 67 is located on the opposite side of the first insulating material 65 with respect to the internal space S of the electrolysis cell 11. The outer size of the first end plate 67 is larger than the outer size of the first insulating material 65, for example.

[0054] (Second end plate) The second end plate 68 is located on the opposite side of the second insulating material 66 with respect to the internal space S of the electrolysis cell 11. The outer size of the second end plate 68 is larger than the outer size of the second insulating material 66, for example.

[0055] The electrolysis cell 11 is not limited to the above-described configuration. For example, when the electrolysis cell stack 10 is configured by arranging a plurality of electrolysis cells 11 side by side, two adjacent electrolysis cells 11 among the plurality of electrolysis cells 11 may share a first separator 41 or a second separator 42, which is a bipolar plate. In this case, there may not be a current collector (first current collector 61 or second current collector 62), an insulator (first insulator 63 or second insulator 64), an insulating material (first insulator 65 or second insulator 66), or an end plate (first end plate 67 or second end plate 68) between the two adjacent electrolysis cells 11.

[0056] (Structure of the outer periphery of the electrolysis cell) FIG. 4 is a cross-sectional view showing the electrolysis cell 11. In this embodiment, the outer size of the ion exchange membrane 50 is larger than each of the outer sizes of the cathode catalyst layer 54 and the cathode power supply 55. In other words, the area of ​​the ion exchange membrane 50 is larger than each of the area of ​​the cathode catalyst layer 54 and the area of ​​the cathode power supply 55. The ion exchange membrane 50 protrudes outward (toward the outer periphery) from the cathode catalyst layer 54 and the cathode power supply 55 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 specification, the terms "outward" and "outer periphery" refer 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] As shown in Fig. 4, 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 an outer edge portion 50e of the ion exchange membrane 50 and supports the ion exchange membrane 50. In this specification, the "outer edge portion 50e" refers to an edge portion that is distant from the center C of the membrane electrode assembly 43 in a direction (e.g., the X direction or the Y direction) perpendicular to the thickness direction (Z direction) of the membrane electrode assembly 43. In addition, the "inside" or "inner circumferential side" in this specification refers to the inside (the side closer to the center C) when viewed from the center C of the membrane electrode assembly 43. In this embodiment, the support portion 70 includes, for example, a first support portion 71 and a second support portion 72.

[0059] (First support part) The first support portion 71 is a support portion 70 on the cathode 47 side. The first support portion 71 is disposed between the first inner surface 41a of the first separator 41 and the first surface 50a of the ion exchange membrane 50. The first support portion 71 is located inside (on the inner circumferential side) of the outer edge portion 50e of the ion exchange membrane 50. The first support portion 71 is sandwiched between the first inner surface 41a of the first separator 41 (or the first insulator 63) and the first surface 50a of the ion exchange membrane 50 at a position outside (on the outer circumferential side) of the cathode catalyst layer 54 and the cathode current collector 55, and supports the ion exchange membrane 50 against the first inner surface 41a of the first separator 41. The first support portion 71 is formed in an annular shape (e.g., frame-shaped) along the outer edge portion 50e of the ion exchange membrane 50 and is one size smaller than the outer edge portion 50e of the ion exchange membrane 50.

[0060] (Second support part) The second support portion 72 is the support portion 70 on the anode 48 side. The second support portion 72 is disposed between the second inner surface 42a of the second separator 42 and the second surface 50b of the ion exchange membrane 50. The second support portion 72 is located inside (on the inner circumferential side) of the outer edge portion 50e of the ion exchange membrane 50. The second support portion 72 is sandwiched between the second inner surface 42a of the second separator 42 and the second surface 50b of the ion exchange membrane 50 at a position outside (on the outer circumferential side) of the anode catalyst layer 56 and the anode current collector 57, and supports the ion exchange membrane 50 against the second inner surface 42a of the second separator 42. The second support portion 72 is annular (e.g., frame-shaped) along the outer edge portion 50e of the ion exchange membrane 50 and is formed into an annular shape that is one size smaller than the outer edge portion 50e of the ion exchange membrane 50.

[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 50e of the ion exchange membrane 50, 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. Furthermore, the sealing portion 80 may be integrally formed with at least one of the first insulator 63 and the second insulator 64 described above.

[0062] (First sealing part) The first sealing portion 81 is the sealing portion 80 on the cathode 47 side. The first sealing portion 81 is located outside (on the outer periphery side) of the outer edge portion 50e of the ion exchange membrane 50. 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. In the present embodiment, the first sealing portion 81 is sandwiched between the first insulator 63 attached to the first inner surface 41a and the second sealing portion 82. The first sealing portion 81 is formed in a ring shape (for example, a frame shape) that follows the outer edge portion 50e of the ion exchange membrane 50 and is one size larger than the outer edge portion 50e of the ion exchange membrane 50.

[0063] (Second sealing part) The second sealing portion 82 is the sealing portion 80 on the anode 48 side. The second sealing portion 82 is located outside the outer edge portion 50e of the ion exchange membrane 50. 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. In the present embodiment, the second sealing portion 82 is sandwiched between the second insulator 64 attached to the second inner surface 42a and the first sealing portion 81. The second sealing portion 82 is formed in a ring shape (for example, a frame shape) that follows the outer edge portion 50e of the ion exchange membrane 50 and is one size larger than the outer edge portion 50e of the ion exchange membrane 50.

[0064] (Method for manufacturing membrane electrode assembly) Next, a method for manufacturing the membrane electrode assembly 43 will be described. FIG. 5 is a cross-sectional view showing a method for manufacturing the membrane electrode assembly 43.

[0065] First, as shown in FIG. 5(a), a cathode catalyst layer 54 is provided on the cathode surface 55a of the cathode current collector 55 (one surface of the cathode current collector 55). The cathode catalyst layer 54 is formed, for example, by applying (coating) a material for the cathode catalyst layer 54 to the cathode surface 55a of the cathode current collector 55, and then pressing the applied material for the cathode catalyst layer 54 and the cathode current collector 55 together at a predetermined temperature and a predetermined pressure. Similarly, an anode catalyst layer 56 is provided on the anode surface 57a of the anode current collector 57 (one surface of the anode current collector 57). The anode catalyst layer 56 is formed, for example, by applying (coating) a material for the anode catalyst layer 56 to the anode surface 57a of the anode current collector 57, and then pressing the applied material for the anode catalyst layer 56 and the anode current collector 57 together at a predetermined temperature and a predetermined pressure. The material for the cathode catalyst layer 54 and the material for the anode catalyst layer 56 can be applied by, for example, a coating method, a CVD (Chemical Vapor Deposition) method, an electroless plating method, a method using a catalyst ink, or a method of applying a catalyst by spraying.

[0066] Next, as shown in FIG. 5(b), the first ionomer layer 52 is provided on the cathode catalyst layer 54. The first ionomer layer 52 is formed, for example, by applying (coating) the material for the first ionomer layer 52 to the cathode catalyst layer 54, and then pressing the applied material for the first ionomer layer 52 and the cathode catalyst layer 54 together at a predetermined temperature and a predetermined pressure. This results in the formation of the first ionomer layer 52 on the cathode catalyst layer 54, separate from the cathode catalyst layer 54. Similarly, the second ionomer layer 53 is provided on the anode catalyst layer 56. The second ionomer layer 53 is formed, for example, by applying (coating) the material for the second ionomer layer 53 to the anode catalyst layer 56, and then pressing the applied material for the second ionomer layer 53 and the anode catalyst layer 56 together at a predetermined temperature and a predetermined pressure. As a result, a second ionomer layer 53 separate from the anode catalyst layer 56 is formed on the anode catalyst layer 56. The materials for the first ionomer layer 52 and the second ionomer layer 53 can be applied appropriately by, for example, a coating method, a CVD method, an electroless plating method, a method using a catalyst ink, or a method of applying a catalyst by spraying.

[0067] 5(c), the first ionomer layer 52 formed on the cathode catalyst layer 54 is placed on the first surface 50a of the ion exchange membrane 50 and pressed at a predetermined temperature and a predetermined pressure, thereby bonding the cathode 47 (cathode catalyst layer 54 and cathode current collector 55) and the ion exchange membrane 50 to each other via the first ionomer layer 52. Similarly, the second ionomer layer 53 formed on the anode catalyst layer 56 is placed on the second surface 50b of the ion exchange membrane 50 and pressed by hot or cold pressing at a predetermined temperature and a predetermined pressure, thereby bonding the anode 48 (anode catalyst layer 56 and anode current collector 57) and the ion exchange membrane 50 to each other via the second ionomer layer 53. As a result, the ionomer layer 51 (the first ionomer layer 52 and the second ionomer layer 53) is provided between the ion exchange membrane 50 and the cathode catalyst layer 54, and between the ion exchange membrane 50 and the anode catalyst layer 56, as a separate body from the cathode catalyst layer 54 and the anode catalyst layer 56, and forms a layer structure together with the cathode catalyst layer 54 and the anode catalyst layer 56. In other words, the membrane electrode assembly 43 is completed.

[0068] (Actions and Effects) As a comparative example, consider a structure in which a cathode catalyst layer 54 and an anode catalyst layer 56 are provided on both sides (first surface 50a and second surface 50b) of an ion exchange membrane 50. Here, when the electrode catalyst layers are formed by coating or the like, the surfaces of the cathode catalyst layer 54 and the anode catalyst layer 56 joined to the ion exchange membrane 50 may be formed to be rough. Therefore, in the membrane electrode assembly 43, due to the surface roughness of the cathode catalyst layer 54 and the anode catalyst layer 56, there may be sparse areas where the cathode catalyst layer 54 and the anode catalyst layer 56 are in close contact with the ion exchange membrane 50 and areas where they are not. As a result, contact resistance decreases at the areas where they are in close contact, which may cause local current concentration and reduce the durability of the membrane.

[0069] On the other hand, in the present embodiment, the membrane electrode assembly 43 includes ionomer layers 51 provided separately from the cathode catalyst layer 54 and the anode catalyst layer 56 between the ion exchange membrane 50 and the cathode catalyst layer 54 and between the ion exchange membrane 50 and the anode catalyst layer 56. The ionomer layers 51 form a layer structure together with the cathode catalyst layer 54 and the anode catalyst layer 56. With this configuration, if recesses are sparsely formed on the surfaces of the cathode catalyst layer 54 and the anode catalyst layer 56, the ionomer layers 51 (the first ionomer layer 52 and the second ionomer layer 53) fill these recesses. That is, the ion exchange membrane 50 is connected to the cathode catalyst layer 54 and the anode catalyst layer 56 via the ionomer layers 51 with the recesses on the surfaces of the cathode catalyst layer 54 and the anode catalyst layer 56 filled. Therefore, the contact resistance between the cathode catalyst layer 54 and the ion exchange membrane 50 and between the anode catalyst layer 56 and the ion exchange membrane 50 is reduced, and current concentration is suppressed, thereby improving the performance of the membrane electrode assembly 43.

[0070] Furthermore, in this embodiment, the ionomer layer 51 provided on the cathode catalyst layer 54 is provided on the first surface 50a of the ion exchange membrane 50, and the ionomer layer 51 provided on the anode catalyst layer 56 is provided on the second surface 50b of the ion exchange membrane 50. This allows the two ionomer layers 51 to be handled separately. This facilitates handling during the manufacturing process, thereby improving productivity.

[0071] Second Embodiment Next, a second embodiment will be described with reference to Fig. 6. Fig. 6 is a cross-sectional view showing a method for manufacturing a membrane electrode assembly 43 according to the second embodiment. In the second embodiment, the method for manufacturing the membrane electrode assembly 43 differs from the method for manufacturing the membrane electrode assembly 43 described in the first embodiment.

[0072] First, as shown in FIG. 6(a), a first ionomer layer 52 is provided on a first surface 50a of an ion exchange membrane 50. The first ionomer layer 52 is formed, for example, by applying (coating) a material for the first ionomer layer 52 to the first surface 50a of the ion exchange membrane 50, and then pressing the applied material for the first ionomer layer 52 and the ion exchange membrane 50 together at a predetermined temperature and a predetermined pressure. Similarly, a second ionomer layer 53 is provided on a second surface 50b of the ion exchange membrane 50. The second ionomer layer 53 is formed, for example, by applying (coating) a material for the second ionomer layer 53 to the second surface 50b of the ion exchange membrane 50, and then pressing the applied material for the second ionomer layer 53 and the ion exchange membrane 50 together at a predetermined temperature and a predetermined pressure. The materials for the first ionomer layer 52 and the second ionomer layer 53 can be applied by, for example, a coating method, a CVD method, an electroless plating method, a method using a catalyst ink, or a method of applying a catalyst by spraying.

[0073] Next, as shown in FIG. 6(b), the cathode catalyst layer 54 provided on the cathode surface 55a of the cathode current collector 55 is placed on the first ionomer layer 52 formed on the first surface 50a of the ion exchange membrane 50. Then, the cathode catalyst layer 54 is pressed on the first ionomer layer 52 by hot or cold pressing at a predetermined temperature and a predetermined pressure, thereby bonding the cathode 47 (cathode catalyst layer 54 and cathode current collector 55) and the ion exchange membrane 50 together via the first ionomer layer 52. As a result, the first ionomer layer 52 separate from the cathode catalyst layer 54 is formed on the cathode catalyst layer 54. Similarly, the anode catalyst layer 56 provided on the anode surface 57a of the anode current collector 57 is placed on the second ionomer layer 53 formed on the second surface 50b of the ion exchange membrane 50. Then, the anode catalyst layer 56 is superimposed on the second ionomer layer 53 and hot or cold pressed at a predetermined temperature and a predetermined pressure, thereby bonding the anode 48 (anode catalyst layer 56 and anode current collector 57) and the ion exchange membrane 50 to each other via the second ionomer layer 53. As a result, the second ionomer layer 53 is formed on the anode catalyst layer 56 as a separate body from the anode catalyst layer 56. That is, the ionomer layer 51 (first ionomer layer 52 and second ionomer layer 53) is provided between the ion exchange membrane 50 and the cathode catalyst layer 54 and between the ion exchange membrane 50 and the anode catalyst layer 56 as a separate body from the cathode catalyst layer 54 and the anode catalyst layer 56, and forms a layered structure together with the cathode catalyst layer 54 and the anode catalyst layer 56. The method for forming the cathode catalyst layer 54 on the cathode surface 55a of the cathode current collector 55 and the method for forming the anode catalyst layer 56 on the anode surface 57a of the anode current collector 57 may be the method described above with reference to (a) in Figure 5.

[0074] The membrane electrode assembly 43 described in the first embodiment can also be completed by the manufacturing method described in this embodiment.

[0075] (Other embodiments) The above describes in detail the embodiments of the present disclosure with reference to the drawings, but the specific configuration is not limited to this embodiment, and design changes within the scope of the present disclosure are also included.

[0076] For example, in the manufacturing method of the membrane electrode assembly 43 described in the first and second embodiments, a step of independently forming the ionomer layer 51 may be performed before forming the ionomer layer 51. Here, "independently forming" means that the material of the ionomer layer 51 is not provided on the cathode catalyst layer 54 and the anode catalyst layer 56, or the ion exchange membrane 50 by coating (applying) or the like, but only the ionomer layer 51 is formed in an independent step. In this case, two ionomer layers 51 may be formed independently, and then one formed ionomer layer 51 may be provided on each of the anode catalyst layer 56 and the cathode catalyst layer 54. Alternatively, one formed ionomer layer 51 may be provided on each of the first surface 50a and the second surface 50b of the ion exchange membrane 50.

[0077] Furthermore, in the manufacturing methods of the membrane electrode assembly 43 described in the first and second embodiments, the anode catalyst layer 56 may be provided on the anode power supplier 57 so that the area of ​​the anode catalyst layer 56 is larger than the area of ​​the cathode catalyst layer 54. In this case, the anode power supplier 57 is formed to have the same size as the anode catalyst layer 56. That is, the area of ​​the anode 48 is larger than the area of ​​the cathode 47. Specifically, the area ratio of the anode 48 to the cathode 47 (N / P ratio) is, for example, larger than 1.0 and not larger than 1.3.

[0078] <Additional Notes> The membrane electrode assembly 43 and the method for manufacturing the membrane electrode assembly 43 described in each embodiment can be understood, for example, as follows.

[0079] (1) A membrane electrode assembly 43 according to a first embodiment includes an ion exchange membrane 50 having a first surface 50 a and a second surface 50 b located opposite the first surface 50 a, a cathode catalyst layer 54 disposed closer to the first surface 50 a than the ion exchange membrane 50, an anode catalyst layer 56 disposed closer to the second surface 50 b than the ion exchange membrane 50, and ionomer layers 51 provided between the ion exchange membrane 50 and the cathode catalyst layer 54 and between the ion exchange membrane 50 and the anode catalyst layer 56 as separate entities from the cathode catalyst layer 54 and the anode catalyst layer 56 and forming a layer structure together with the cathode catalyst layer 54 and the anode catalyst layer 56.

[0080] As a result, if recesses are sparsely formed on the surfaces of the cathode catalyst layer 54 and the anode catalyst layer 56, the ionomer layer 51 will fill these recesses. That is, with the recesses on the surfaces of the cathode catalyst layer 54 and the anode catalyst layer 56 filled, the ion exchange membrane 50 will be connected to the cathode catalyst layer 54 and the anode catalyst layer 56 via the ionomer layer 51.

[0081] (2) A membrane electrode assembly 43 according to a second aspect is the membrane electrode assembly 43 of (1), wherein the ionomer layer 51 is composed of an ionomer resin component and a non-ionomer resin component different from the ionomer resin component, and the ionomer resin component may be contained in the ionomer layer 51 at a ratio of 80% by mass or more and less than 100% by mass.

[0082] This allows the above-mentioned effects to be realized with higher precision.

[0083] (3) A membrane electrode assembly 43 according to a third aspect is the membrane electrode assembly 43 of (2), wherein the ionomer resin component may contain a composition having the same composition as an additive contained in common in the ion exchange membrane 50, the cathode catalyst layer 54, and the anode catalyst layer 56.

[0084] This makes it possible to improve the adhesion between the ionomer layer 51 and the ion exchange membrane 50, between the ionomer layer 51 and the cathode catalyst layer 54, and between the ionomer layer 51 and the anode catalyst layer 56.

[0085] (4) A membrane electrode assembly 43 according to a fourth aspect is the membrane electrode assembly 43 of (2) or (3), in which the non-ionomer resin component may contain electrocatalyst particles and a binder.

[0086] This can improve the ionic conductivity and adhesion between the ionomer layer 51 and the ion exchange membrane 50, between the ionomer layer 51 and the cathode catalyst layer 54, and between the ionomer layer 51 and the anode catalyst layer 56.

[0087] (5) A membrane electrode assembly 43 according to a fifth aspect is the membrane electrode assembly 43 of any one of (1) to (4), wherein the thickness of the ionomer layer 51 may be 10% or more and 50% or less of the thickness of the cathode catalyst layer 54 and the thickness of the anode catalyst layer 56.

[0088] This allows the above-mentioned effects to be realized in more specific settings.

[0089] (6) A membrane electrode assembly 43 according to a sixth aspect is the membrane electrode assembly 43 according to any one of (1) to (5), and the thickness of the ionomer layer 51 may be 1 nm or more and 10 μm or less.

[0090] This allows the above-mentioned effects to be realized in more specific settings.

[0091] (7) A method for manufacturing a membrane electrode assembly 43 according to the seventh aspect includes the steps of providing an ionomer layer 51 separate from the cathode catalyst layer 54 and the anode catalyst layer 56 on a cathode catalyst layer 54 formed on one surface (cathode surface 55a) of a cathode current collector 55 and an anode catalyst layer 56 formed on one surface (anode surface 57a) of an anode current collector 57; and overlaying the ionomer layer 51 provided on the cathode catalyst layer 54 on a first surface 50a of an ion exchange membrane 50, and overlaying the ionomer layer 51 provided on the anode catalyst layer 56 on a second surface 50b of the ion exchange membrane 50 located opposite the first surface 50a, and hot or cold pressing the layers to form a layer structure.

[0092] This allows the ionomer layer 51 provided on the cathode catalyst layer 54 and the ionomer layer 51 provided on the anode catalyst layer 56 to be handled separately, which facilitates handling during the manufacturing process and improves productivity.

[0093] (8) A method for manufacturing a membrane electrode assembly 43 according to the eighth embodiment includes the steps of providing an ionomer layer 51 on each of a first surface 50a of an ion exchange membrane 50 and a second surface 50b opposite the first surface 50a, and overlaying a cathode catalyst layer 54 provided on one surface (cathode surface 55a) of a cathode current collector 55 on the ionomer layer 51 provided on the first surface 50a of the ion exchange membrane 50 so as to be separate from the ionomer layer 51, and overlaying an anode catalyst layer 56 provided on one surface of an anode current collector 57 on the ionomer layer 51 provided on the second surface 50b of the ion exchange membrane 50 so as to be separate from the ionomer layer 51, and hot or cold pressing the resulting layers to form a layer structure.

[0094] In this way, the above-mentioned membrane electrode assembly 43 can be manufactured.

[0095] (9) A manufacturing method of a membrane electrode assembly 43 according to a ninth aspect is the manufacturing method of the membrane electrode assembly 43 of (7) or (8), in which, before performing the step of providing the ionomer layer 51, a step of molding the ionomer layer 51 alone may be performed, and the membrane electrode assembly may be formed by hot or cold pressing. [Explanation of symbols]

[0096] 1...Electrolysis device 10...Electrolytic cell stack 11...Electrolytic cell 20...Electrolyte supply section 20a...Cathode side supply section 20b...Anode side supply section 21...Hydrogen gas-liquid separator 22...First pump 23...Hydrogen recovery section 24...First electrolyte supply section 26...Oxygen gas-liquid separator 27...Second pump 28...Oxygen recovery section 29...Second electrolyte supply section 30...Power supply section 40...Electrolytic cell 41...First separator 41a...First inner surface 41b, 42b...Opposite surface of first inner surface, opposite surface of second inner surface 41e1, 42e1...First separator end 41e2, 42e2...Second separator end 42...Second separator 42a...Second inner surface 43...Membrane electrode assembly 47...Cathode 48...Anode 50...Ion exchange membrane 50a...First surface 50b...Second surface 50e...Outer edge portion 51...Ionomer layer 52...First ionomer layer 53...Second ionomer layer 54...Cathode catalyst layer 55...Cathode current collector 55a...Cathode surface 56...Anode catalyst layer 57...Anode current collector 57a...Anode surface 61...First current collector 62...Second current collector 63...First insulator 64...Second insulator 65...First insulating material 66...Second insulating material 67...First end plate 68...Second end plate 70...Support portion 71...First supporting portion 72...Second supporting portion 80...Sealing portion 81...First sealing portion 82...Second sealing portion C...Central portion FP1...First flow path FP2...Second flow path L1, L2, L3, L4...Piping lines S...Internal space Sa...Cathode chamber Sb...Anode chamber

Claims

1. an ion exchange membrane having a first surface and a second surface opposite the first surface; a cathode catalyst layer disposed closer to the first surface than the ion exchange membrane; an anode catalyst layer disposed closer to the second surface than the ion exchange membrane; an ionomer layer provided separately from the cathode catalyst layer and the anode catalyst layer between the ion exchange membrane and the cathode catalyst layer and between the ion exchange membrane and the anode catalyst layer, the ionomer layer forming a layer structure together with the cathode catalyst layer and the anode catalyst layer; Equipped with The ionomer layer comprises: an ionomer resin component; a non-ionomer resin component different from the ionomer resin component; It is composed of the ionomer resin component is contained in the ionomer layer in a proportion of 80% by mass or more and less than 100% by mass, a membrane electrode assembly, wherein the ionomer resin component contains a composition having the same composition as an additive contained in common in the ion exchange membrane, the cathode catalyst layer, and the anode catalyst layer;

2. 10. The membrane electrode assembly of claim 1, wherein the non-ionomeric resin component comprises electrocatalyst particles and a binder.

3. an ion exchange membrane having a first surface and a second surface opposite the first surface; a cathode catalyst layer disposed closer to the first surface than the ion exchange membrane; an anode catalyst layer disposed closer to the second surface than the ion exchange membrane; an ionomer layer provided separately from the cathode catalyst layer and the anode catalyst layer between the ion exchange membrane and the cathode catalyst layer and between the ion exchange membrane and the anode catalyst layer, the ionomer layer forming a layer structure together with the cathode catalyst layer and the anode catalyst layer; Equipped with The ionomer layer comprises: an ionomer resin component; a non-ionomer resin component different from the ionomer resin component; It is composed of the ionomer resin component is contained in the ionomer layer in a proportion of 80% by mass or more and less than 100% by mass, The non-ionomer resin component of the membrane electrode assembly includes electrocatalyst particles and a binder.

4. 3. The membrane electrode assembly according to claim 1, wherein the thickness of the ionomer layer is 10% to 50% of the thickness of the cathode catalyst layer and the thickness of the anode catalyst layer.

5. 3. The membrane electrode assembly according to claim 1, wherein the ionomer layer has a thickness of 1 nm or more and 10 μm or less.

6. providing an ionomer layer separate from the cathode catalyst layer and the anode catalyst layer on a cathode current collector and an anode catalyst layer formed on one side of the anode current collector; the ionomer layer provided in the cathode catalyst layer is superposed on a first surface of the ion exchange membrane, and the ionomer layer provided in the anode catalyst layer is superposed on a second surface of the ion exchange membrane opposite to the first surface, and the two layers are hot or cold pressed to form a layer structure; Run The ionomer layer comprises: an ionomer resin component; a non-ionomer resin component different from the ionomer resin component; It is composed of the ionomer resin component is contained in the ionomer layer in a proportion of 80% by mass or more and less than 100% by mass, The method for producing a membrane electrode assembly, wherein the ionomer resin component contains a composition having the same composition as an additive contained in common in the ion exchange membrane, the cathode catalyst layer, and the anode catalyst layer.

7. providing an ionomer layer separate from the cathode catalyst layer and the anode catalyst layer on a cathode current collector and an anode catalyst layer formed on one side of the anode current collector; the ionomer layer provided in the cathode catalyst layer is superposed on a first surface of the ion exchange membrane, and the ionomer layer provided in the anode catalyst layer is superposed on a second surface of the ion exchange membrane opposite to the first surface, and the two layers are hot or cold pressed to form a layer structure; Run The ionomer layer comprises: an ionomer resin component; a non-ionomer resin component different from the ionomer resin component; It is composed of the ionomer resin component is contained in the ionomer layer in a proportion of 80% by mass or more and less than 100% by mass, The non-ionomer resin component comprises electrocatalyst particles and a binder.

8. providing an ionomer layer on each of a first surface of the ion exchange membrane and a second surface opposite the first surface; a step of superposing a cathode catalyst layer provided on one side of a cathode current collector on the ionomer layer provided on the first side of the ion exchange membrane so as to be separate from the ionomer layer, and anode catalyst layer provided on one side of an anode current collector on the ionomer layer provided on the second side of the ion exchange membrane so as to be separate from the ionomer layer, and hot or cold pressing the resulting mixture to form a layer structure; Run The ionomer layer comprises: an ionomer resin component; a non-ionomer resin component different from the ionomer resin component; It is composed of the ionomer resin component is contained in the ionomer layer in a proportion of 80% by mass or more and less than 100% by mass, The method for producing a membrane electrode assembly, wherein the ionomer resin component contains a composition having the same composition as an additive contained in common in the ion exchange membrane, the cathode catalyst layer, and the anode catalyst layer.

9. providing an ionomer layer on each of a first surface of the ion exchange membrane and a second surface opposite the first surface; a step of superposing a cathode catalyst layer provided on one side of a cathode current collector on the ionomer layer provided on the first side of the ion exchange membrane so as to be separate from the ionomer layer, and anode catalyst layer provided on one side of an anode current collector on the ionomer layer provided on the second side of the ion exchange membrane so as to be separate from the ionomer layer, and hot or cold pressing the resulting mixture to form a layer structure; Run The ionomer layer comprises: an ionomer resin component; a non-ionomer resin component different from the ionomer resin component; It is composed of the ionomer resin component is contained in the ionomer layer in a proportion of 80% by mass or more and less than 100% by mass, The non-ionomer resin component comprises electrocatalyst particles and a binder.

10. 10. The method for manufacturing a membrane electrode assembly according to claim 6, wherein, before the step of providing the ionomer layer, a step of molding the ionomer layer alone is carried out, and the ionomer layer is hot or cold pressed to form the membrane electrode assembly.

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