Separator and water electrolysis cell

Abstract

The present invention provides a separator and a water electrolysis cell. The separator is used in a water electrolysis device utilizing an ion exchange membrane and includes: a separator body in which a plurality of channel grooves are provided on a surface section; and a header in which an opening for arranging the separator body is provided in a center section, an electrolyte supply part is provided on one side of the channel grooves, and gas and electrolyte discharge parts are provided on the other side. The separator body and the header are provided separately and are formed of different materials.

Description

Separators and water electrolysis cells

[0001] The present disclosure relates to a separator and a water electrolysis cell.

[0002] Water electrolysis devices that produce hydrogen by electrolyzing an aqueous solution are being put into practical use. Water electrolysis devices produce hydrogen gas and oxygen gas by electrolyzing an aqueous solution. The water electrolysis device includes a water electrolysis cell. The water electrolysis cell includes a cathode catalyst layer and an anode catalyst layer disposed on either side of an ion exchange membrane, power feeders disposed outside the cathode catalyst layer and the anode catalyst layer, and separators disposed outside each power feeder.

[0003] Such a water electrolysis device is disclosed in, for example, Patent Document 1.

[0004] Patent No. 3254116

[0005] The separator used in a water electrolysis cell is made of a metal plate material. The separator has multiple grooves in the center, an electrolyte supply port on one side of the multiple grooves, and hydrogen gas, oxygen gas, and electrolyte discharge ports on the other side. The separator is generally formed by press forming. When a metal plate material is press formed to form a separator, distortion is likely to occur around the multiple grooves. Multiple separators are stacked, and sealing members are placed between each separator to prevent liquid leakage from the grooves. However, when distortion occurs around the grooves, the sealing performance of the sealing members deteriorates, making it difficult to adequately prevent liquid leakage from the grooves.

[0006] The present disclosure is intended to solve the above-mentioned problems, and aims to provide a separator and a water electrolysis cell that achieve improved sealing performance.

[0007] To achieve the above object, the separator of the present disclosure is used in a water electrolysis device that uses an ion exchange membrane, and includes a separator body having a plurality of flow path grooves on its surface, and a header having an opening in its center for arranging the separator body, an electrolyte solution supply section on one side of the flow path grooves, and a gas and electrolyte solution discharge section on the other side, wherein the separator body and the header are provided separately and are made of different materials.

[0008] The water electrolysis cell according to the present disclosure includes an ion exchange membrane, a cathode-side catalyst layer and an anode-side catalyst layer disposed on either side of the ion exchange membrane, a cathode-side current feeder and an anode-side current feeder disposed outside the cathode-side catalyst layer and the anode-side catalyst layer, and the separator according to claim 1 applied as a cathode-side separator and an anode-side separator disposed outside the cathode-side current feeder and the anode-side current feeder.

[0009] The separator and water electrolysis cell of the present disclosure can improve sealing performance.

[0010] FIG. 1 is a schematic cross-sectional view of a water electrolysis cell according to this embodiment. FIG. 2 is an exploded perspective view of a water electrolysis cell according to this embodiment. FIG. 3 is a front view of a cathode side separator according to this embodiment. FIG. 4 is a front view of an anode side separator according to this embodiment. FIG. 5 is a cross-sectional view of a separator main body. FIG. 6 is a cross-sectional view (cross-sectional view taken along VI-VI in FIG. 3 ) of a main part of a water electrolysis cell, illustrating the stacking state of separators according to this embodiment. FIG. 7 is an explanatory diagram illustrating a method of assembling a water electrolysis cell. FIG. 8 is an explanatory diagram illustrating a method of assembling a water electrolysis cell. FIG. 9 is an explanatory diagram illustrating a method of assembling a water electrolysis cell. FIG. 10 is an explanatory diagram illustrating a method of assembling a water electrolysis cell.

[0011] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that the present disclosure is not limited to these embodiments, and when there are multiple embodiments, the present disclosure also includes configurations that combine the embodiments. Furthermore, the components in the embodiments include those that can be easily imagined by a person skilled in the art, those that are substantially identical, and those that are within the so-called equivalent range.

[0012] [Embodiment] <Water Electrolysis Apparatus> A water electrolysis apparatus is a device for electrolyzing water (H ２ By electrolyzing hydrogen (H ２ The water electrolysis device is, for example, a device using an anion exchange membrane (AEM). However, the water electrolysis device may also be, for example, a device using a proton exchange membrane (PEM: Polymer Electrolyte Membrane).

[0013] The water electrolysis device includes, for example, a cell stack, an electrolyte supply unit, and a power supply unit. The cell stack, which will be described later, is an assembly of water electrolysis cells. The electrolyte supply unit supplies the electrolyte to the water electrolysis cells. The electrolyte is, for example, pure water or an alkaline aqueous solution. An example of the alkaline aqueous solution is potassium hydroxide (KOH). The electrolyte supply unit has a cathode-side supply unit and an anode-side supply unit. The power supply unit is a DC power supply device that applies a voltage to the water electrolysis cells. The power supply unit applies a DC voltage required for electrolysis of the electrolyte between the cathode and anode of the water electrolysis cell.

[0014] <Water Electrolysis Cell> FIG. 1 is a schematic cross-sectional view showing a water electrolysis cell according to this embodiment.

[0015] 1 , the water electrolysis cell 10 is a device that generates hydrogen by electrolyzing water contained in an electrolyte solution using externally input electrical energy. The water electrolysis cell 10 includes, for example, a cathode separator 11, an anode separator 12, and a membrane electrode assembly 13.

[0016] <Cathode-side separator> The cathode-side separator 11 is a member that defines one side of the accommodation space of the water electrolysis cell 10. The cathode-side separator 11 has, for example, a rectangular plate shape. A negative voltage is applied to the cathode-side separator 11 from the power supply unit 14 via, for example, a first power feeder 33 (see FIG. 2 ) described below. An electrolyte supply line L1 is connected to one end of the cathode-side separator 11. An electrolyte discharge line L2 is connected to the other end of the cathode-side separator 11.

[0017] <Anode-side separator> The anode-side separator 12 is a member that defines the other side of the accommodation space of the water electrolysis cell 10. The anode-side separator 12 has, for example, a rectangular plate shape. A positive voltage is applied to the anode-side separator 12 from the power supply unit 14 via, for example, a second power feeder 34 (see FIG. 2 ) described below. An electrolyte solution supply line L3 is connected to one end of the anode-side separator 12. An electrolyte solution discharge line L4 is connected to the other end of the anode-side separator 12.

[0018] The cathode side separator 11 and the anode side separator 12 will be described in detail below.

[0019] <Configuration of Membrane Electrode Assembly> The membrane electrode assembly (MEA) 13 is a structure in which an ion exchange membrane, a catalyst, and a power supply are assembled. The membrane electrode assembly 13 is disposed between a cathode side separator 11 and an anode side separator 12, and is located in a storage space. The membrane electrode assembly 13 includes, for example, an ion exchange membrane 21, a cathode side catalyst layer 22, an anode side catalyst layer 23, a cathode side power supply 24, and an anode side power supply 25. In the membrane electrode assembly 13, the cathode side catalyst layer 22 and the cathode side power supply 24 constitute a cathode relative to the ion exchange membrane 21, and the anode side catalyst layer 23 and the anode side power supply 25 constitute an anode.

[0020] <Ion Exchange Membrane> The ion exchange membrane 21 is a membrane that selectively allows ions to pass through. The ion exchange membrane 21 is, for example, a solid polymer electrolyte membrane. The ion exchange membrane 21 is, for example, an anion exchange membrane (AEM) that is conductive to hydroxide ions (OH-). However, the ion exchange membrane 21 is not limited to an anion exchange membrane, and may be, for example, a proton exchange membrane (PEM) of a type different from an anion exchange membrane.

[0021] The ion exchange membrane 21 is, for example, in the form of a rectangular sheet and is flexible. The outer size of the ion exchange membrane 21 is smaller than the outer size of the cathode side separator 11 or the anode side separator 12. The ion exchange membrane 21 is disposed between the cathode side separator 11 and the anode side separator 12 and is located in the storage space.

[0022] When a voltage is applied to the water electrolysis cell 10 by the power supply 14, the following chemical reaction occurs on the cathode side of the ion exchange membrane 21, and hydrogen is produced from the electrolyte. The produced hydroxide ions pass through the membrane electrode assembly 13 from the cathode side to the anode side. ２ O + 2e － →H ２ +2OH －

[0023] When a voltage is applied to the water electrolysis cell 10 by the power supply 14, the following chemical reaction occurs on the anode side of the ion exchange membrane 21, and oxygen is produced from the electrolyte: － →1 / 2O ２ +H ２ O + 2e －

[0024] As a result, the following chemical reactions occur in the water electrolysis cell 10 as a whole: ２ O → H ２ +1 / 2O ２

[0025] The ion exchange membrane 21 may have a polystyrene-based or tetraphenyl-based composition in the main chain and an imidazolium group or a quaternary ammonium group in the side chain, as an example of a membrane with relatively high ionic conductivity. Alternatively, the ion exchange membrane 21 may have a polysulfone-based or bromobutylstyrene-based composition, as an example of a membrane with relatively high oxidation resistance.

[0026] <Cathode-side catalyst layer> The cathode-side catalyst layer 22 is a layer (electrode-side catalyst layer) that promotes the chemical reaction of water electrolysis. The cathode-side catalyst layer 22 has, for example, a rectangular sheet shape. The outer size of the cathode-side catalyst layer 22 is, for example, smaller than the outer size of the ion exchange membrane 21. The cathode-side catalyst layer 22 is provided on one side of the ion exchange membrane 21. A cathode-side power supply 24 is connected to the cathode-side catalyst layer 22 from the side opposite to the ion exchange membrane 21. A negative voltage is applied to the cathode-side catalyst layer 22 from the power supply 14 via the cathode-side separator 11 and the cathode-side power supply 24, and the cathode-side catalyst layer 22 functions as part of the cathode of the water electrolysis cell 10.

[0027] The cathode-side catalyst layer 22 may be made of any material that promotes chemical reactions. For example, the cathode-side catalyst layer 22 may contain one or more of nickel, a nickel alloy, cerium oxide, lanthanum oxide, and platinum (Pt). In addition to the above-mentioned materials, the cathode-side catalyst layer 22 may also contain another material, such as carbon.

[0028] <Anode-side catalyst layer> The anode-side catalyst layer 23 is a layer (electrode-side catalyst layer) that promotes the chemical reaction of water electrolysis. The anode-side catalyst layer 23 has, for example, a rectangular sheet shape. The outer size of the anode-side catalyst layer 23 is, for example, smaller than the outer size of the ion exchange membrane 21. The anode-side catalyst layer 23 is provided on the other surface of the ion exchange membrane 21. An anode-side power supply 25 is connected to the anode-side catalyst layer 23 from the side opposite to the ion exchange membrane 21. A positive voltage is applied to the anode-side catalyst layer 23 from the power supply 14 via the anode-side separator 12 and the anode-side power supply 25, and the anode-side catalyst layer 23 functions as part of the anode of the water electrolysis cell 10.

[0029] The anode-side catalyst layer 23 may be made of any material that promotes chemical reactions, and various materials may be used. For example, the anode-side catalyst layer 23 may contain one or more of nickel, nickel alloy, nickel oxide, copper oxide, iridium oxide, niobium oxide, lead oxide, and bismuth oxide. In addition to the above-mentioned materials, the anode-side catalyst layer 23 may also contain another material, such as carbon.

[0030] <Cathode power supplier> The cathode side power supplier 24 is an electrical connection part that transmits a voltage applied to the cathode side separator 11 to the cathode side catalyst layer 22. The cathode side power supplier 24 is located between the cathode side separator 11 and the cathode side catalyst layer 22, with one surface in contact with the cathode side separator 11 and the other surface in contact with the cathode side catalyst layer 22.

[0031] The cathode side current collector 24 has a structure that allows the electrolyte and gas to pass through it. The cathode side current collector 24 is formed, for example, from a metal mesh structure, a sintered body, fiber, a conductive carbon fiber mesh structure, or nonwoven fabric. The cathode side current collector 24 has a predetermined porosity. The cathode side current collector 24 has the same external size as the cathode side catalyst layer 22. The cathode side catalyst layer 22 and the cathode side current collector 24 together constitute the cathode of the water electrolysis cell 10.

[0032] <Anode power supplier> The anode-side power supplier 25 is an electrical connection part that transmits a voltage applied to the anode-side separator 12 to the anode-side catalyst layer 23. The anode-side power supplier 25 is located between the anode-side separator 12 and the anode-side catalyst layer 23, with one surface in contact with the anode-side separator 12 and the other surface in contact with the anode-side catalyst layer 23.

[0033] The anode side current collector 25 has a structure that allows the electrolyte and gas to pass through it. The anode side current collector 25 is formed, for example, of a metal mesh structure, a sintered body, fiber, a conductive carbon fiber mesh structure, or nonwoven fabric. The anode side current collector 25 has a predetermined porosity. The anode side current collector 25 has, for example, the same porosity as the cathode side current collector 24. The external size of the anode side current collector 25 is the same as the external size of the anode side catalyst layer 23. The anode side catalyst layer 23 and the anode side current collector 25 together constitute the anode of the water electrolysis cell 10.

[0034] FIG. 2 is an exploded perspective view showing the water electrolysis cell of this embodiment.

[0035] As shown in FIG. 2 , the water electrolysis cell 10 includes, in addition to a cathode separator 11, an anode separator 12, and a membrane electrode assembly 13 (denoted by 22, 24, 21, 23, and 25 in FIG. 2 ), insulators 31 and 32, power feeders 33 and 34, insulating materials 35 and 36, and end plates 37 and 38, for example.

[0036] <Insulators> The insulators 31, 32 are members that provide insulation between the outer periphery of the cathode side separator 11 and the outer periphery of the anode side separator 12. The insulator 31 arranged on the cathode side is a frame-shaped sheet member whose outer shape is slightly larger than that of the cathode side separator 11. The insulator 31 contacts and covers a cathode side header 42 (described later) of the cathode side separator 11. The insulator 32 arranged on the anode side is a frame-shaped sheet member whose outer shape is slightly larger than that of the anode side separator 12. The insulator 32 contacts and covers an anode side header 44 (described later) of the anode side separator 12. The material of the insulators 31, 32 is not particularly limited as long as it is an insulating material, and may be, for example, a sheet-shaped resin such as PTFE.

[0037] <Power Supply Element> The power supply element 33 is an electrical connection element that transmits a negative voltage applied from the power supply unit 14 to the cathode side separator 11. The power supply element 33 is a metal plate member (e.g., a copper plate). The power supply element 33 contacts the cathode side separator 11, for example, from the side opposite to the housing space of the water electrolysis cell 10, and is electrically connected to the cathode side separator 11. The negative voltage required for electrolysis in the water electrolysis cell 10 is applied to the power supply element 33 from the power supply unit 14.

[0038] The power supply 34 is an electrical connection part that transmits a positive voltage applied from the power supply unit 14 to the anode side separator 12. The power supply 34 is a metal plate member (e.g., a copper plate). The power supply 34 contacts the anode side separator 12, for example, from the side opposite to the housing space of the water electrolysis cell 10, and is electrically connected to the anode side separator 12. The power supply 14 applies to the power supply 33 a positive voltage required for electrolysis in the water electrolysis cell 10.

[0039] <Insulating Material> The insulating material 35 is located on the outside of the power feeder 33. The outer size of the insulating material 35 is, for example, the same as or larger than the outer size of the power feeder 33. The insulating material 36 is located on the outside of the power feeder 34. The outer size of the insulating material 36 is, for example, the same as or larger than the outer size of the power feeder 34.

[0040] <End Plate> The end plate 37 is located on the opposite side of the insulating material 35 with respect to the accommodation space of the water electrolysis cell 10. The end plate 37 is formed, for example, from a metal plate member (e.g., a stainless steel plate). The outer size of the end plate 37 is, for example, the same as or larger than the outer size of the insulating material 35.

[0041] The end plate 38 is located on the opposite side of the insulating material 36 with respect to the accommodation space of the water electrolysis cell 10. The end plate 38 is formed, for example, from a metal plate member (e.g., a stainless steel plate). The outer size of the end plate 38 is, for example, the same as or larger than the outer size of the insulating material 36.

[0042] The water electrolysis cell 10 is not limited to the above-described configuration. For example, the water electrolysis cell 10 may be configured by stacking multiple cathode-side separators 11, anode-side separators 12, and membrane electrode assemblies 13.

[0043] <Separator Configuration> FIG. 3 is a front view of the cathode-side separator of this embodiment, FIG. 4 is a front view of the anode-side separator of this embodiment, and FIG. 5 is a cross-sectional view of the separator body.

[0044] 2 , the cathode side separator 11 and the anode side separator 12 have substantially the same configuration. The cathode side separator 11 has a cathode side separator body 41 and a cathode side header 42. The anode side separator 12 has an anode side separator body 43 and an anode side header 44.

[0045] As shown in FIG. 3 , in the cathode side separator 11, the cathode side separator body 41 has a corrugated shape obtained by corrugating a rectangular plate material and has a plurality of flow path grooves 51 formed in its surface portion. The cathode side header 42 has a rectangular plate shape and an opening 52 formed in its central portion. The cathode side header 42 has the cathode side separator body 41 disposed in the opening 52. The cathode side header 42 has an electrolyte solution supply hole 53 and an aqueous solution distribution portion 54 formed on one side of the opening 52, i.e., on one side (the lower side in FIG. 3 ) of the cathode side separator body 41 toward the flow path grooves 51. The electrolyte solution supply hole 53 is a through hole that penetrates the cathode side header 42 in the thickness direction. The aqueous solution distribution portion 54 is a recess formed in the surface of the cathode side header 42. The electrolyte solution supply hole 53 and the aqueous solution distribution portion 54 function as electrolyte solution supply portions.

[0046] The cathode side header 42 is provided with a hydrogen gas discharge hole 55 and a hydrogen gas flow portion 56 on the other side of the opening 52, i.e., on the other side of the cathode side separator body 41 in the direction of the flow path groove 51 (upper side in FIG. 3 ). The hydrogen gas discharge hole 55 is a through-hole that penetrates the cathode side header 42 in the thickness direction. The hydrogen gas flow portion 56 is a recess formed in the surface of the cathode side header 42. The hydrogen gas discharge hole 55 and the hydrogen gas flow portion 56 function as gas and electrolyte discharge portions. The cathode side header 42 is provided with an electrolyte supply hole 57 on one side in the direction of the flow path groove 51 (lower side in FIG. 3 ). The cathode side header 42 is provided with an oxygen gas discharge hole 58 on the other side in the direction of the flow path groove 51 (upper side in FIG. 3 ).

[0047] As shown in FIG. 4 , in the anode side separator 12, the anode side separator body 43 has a corrugated shape obtained by corrugating a rectangular plate material, and has a plurality of flow path grooves 61 formed in its surface portion. The anode side header 44 has a rectangular plate shape and an opening 62 formed in its center. The anode side separator body 43 is disposed in the opening 62 of the anode side header 44. The anode side header 44 has an electrolyte solution supply hole 63 and an aqueous solution distribution portion 64 formed on one side of the opening 62, i.e., on one side (the lower side in FIG. 4 ) of the anode side separator body 43 toward the flow path grooves 61. The electrolyte solution supply hole 63 is a through hole penetrating the anode side header 44 in the thickness direction. The aqueous solution distribution portion 64 is a recess formed in the surface of the anode side header 44. The electrolyte solution supply hole 63 and the aqueous solution distribution portion 64 function as electrolyte solution supply portions.

[0048] The anode side header 44 is provided with an oxygen gas discharge hole 65 and an oxygen gas flow portion 66 on the other side of the opening 62, i.e., on the other side of the anode side separator body 43 in the direction of the flow path groove 61 (upper side in FIG. 4 ). The oxygen gas discharge hole 65 is a through-hole that penetrates the anode side header 44 in the thickness direction. The oxygen gas flow portion 66 is a recess formed in the surface of the anode side header 44. The oxygen gas discharge hole 65 and the oxygen gas flow portion 66 function as gas and electrolyte solution discharge portions. The anode side header 44 is provided with an electrolyte solution supply hole 67 on one side in the direction of the flow path groove 61 (lower side in FIG. 4 ). The anode side header 44 is provided with a hydrogen gas discharge hole 68 on the other side in the direction of the flow path groove 61 (upper side in FIG. 4 ).

[0049] 3 and 4 , the cathode side separator 11 has a cathode side separator body 41 and a cathode side header 42 which are separate members and made of different materials. Furthermore, the anode side separator 12 has an anode side separator body 43 and an anode side header 44 which are separate members and made of different materials.

[0050] Specifically, the cathode side separator body 41 and the anode side separator body 43 are formed, for example, from a metal material. The cathode side header 42 and the anode side header 44 are formed from a resin material. The metal material is preferably stainless steel, titanium, nickel, or the like, and is manufactured by press molding, cutting, or the like. Furthermore, the resin material is preferably aramid fiber reinforced resin (AFRP composite material), but may also be glass fiber reinforced resin, or the like.

[0051] The cathode side separator 11 and the anode side separator 12 are stacked in the thickness direction. At this time, the cathode side header 42 and the anode side header 44 are in contact with each other via a seal member 39 (see FIG. 2 ), thereby preventing leakage of the electrolyte to the outside. Meanwhile, a metal plate 45 is disposed between the cathode side separator body 41 and the anode side separator body 43, as shown in FIG. 5 . The metal plate 45 is preferably formed from, for example, the same metal material (stainless steel, titanium, nickel, etc.) as the cathode side separator body 41 and the anode side separator body 43.

[0052] Figure 6 is a cross-sectional view (cross-sectional view taken along line VI-VI in Figure 3) of a main part of a water electrolysis cell, illustrating the stacking state of separators according to this embodiment. In Figure 6, the upper part is a cross-section at a position where a metal plate 45 is arranged, the middle part is a cross-section at a position where an ion exchange membrane 21, a cathode-side catalyst layer 22, an anode-side catalyst layer 23, a cathode-side current feeder 24, and an anode-side current feeder 25 are arranged, and the lower part is a cross-section at a position where a cathode-side header 42 and an anode-side header 44 are arranged opposite each other. The cross-sectional view in Figure 6 schematically illustrates the entire cell with gaps between the respective components.

[0053] 6 , the water electrolysis cell 10 is configured by stacking a plurality of cathode-side separators 11 and a plurality of anode-side separators 12 in the thickness direction. In this case, an ion exchange membrane 21, a cathode-side catalyst layer 22, an anode-side catalyst layer 23, a cathode-side current collector 24, and an anode-side current collector 25, which constitute a membrane electrode assembly 13, are disposed between each cathode-side separator 11 and each anode-side separator 12.

[0054] In the present embodiment, a cathode side separator 11 and multiple anode side separators 12 are stacked in three layers with the cathode side header 42 and the anode side header 44 disposed opposite each other. The three cathode side separators 11 contact each other on their outer peripheries, and sealing performance is ensured by a ring-shaped sealing member 102. Note that the number of stacked cathode side separators 11 and multiple anode side separators 12 is not limited to three.

[0055] In the stacked membrane electrode assemblies 13, a power supply 33 and an insulator 31 are arranged relative to the cathode side separator 11 on one side, and are sealed by a ring-shaped sealing member (not shown). In the stacked membrane electrode assemblies 13, a power supply 34 and an insulator 32 are arranged relative to the anode side separator 12 on the other side, and are sealed by a ring-shaped sealing member (not shown).

[0056] The anode side header 44 has a ring-shaped recess (first recess) 111 provided on one surface 44a of the outer periphery facing the cathode side header 42. The cathode side header 42 has a ring-shaped seal member (first seal portion) 39 disposed in the recess 111. The seal member 39 brings the cathode side header 42 and the anode side header 44 into close contact and also brings the anode side header 44 into close contact with the insulator 32, thereby preventing external leakage of the electrolyte.

[0057] The anode side header 44 has a ring-shaped recess (second recess) 112 on one surface 44a. The recess 112 communicates with the opening 62. The anode side header 44 has a metal plate 45 disposed in the recess 112. The metal plate 45 is disposed between the cathode side separator body 41 and the anode side separator body 43. The metal plate 45 has an outer periphery extending outward and disposed in the recess 112. The anode side header 44 also has a ring-shaped recess (third recess) 113 disposed on the outer periphery side of the recess 112. The anode side header 44 has a ring-shaped seal member (second seal portion) 114 disposed in the recess 113. The seal member 114 is in close contact with the metal plate 45 to prevent external leakage of the electrolytic solution.

[0058] The cathode side header 42 has a ring-shaped recess (fourth recess) 115 on one surface 42a. The recess 115 communicates with the opening 52. The cathode side header 42 has a cathode side catalyst layer 22, a cathode side power supply 24, an ion exchange membrane 21, an anode side catalyst layer 23, and an anode side power supply 25 arranged in a stacked state in the recess 115. The ion exchange membrane 21, the anode side catalyst layer 23, and the anode side power supply 25 have outer peripheries extending outward beyond the cathode side catalyst layer 22 and the cathode side power supply 24. The cathode side header 42 also has a ring-shaped recess (fifth recess) 116 arranged on the outer periphery of the recess 115. The cathode side header 42 has a ring-shaped seal member (third seal portion) 117 arranged in the recess 116. The seal member 117 is in close contact with the ion exchange membrane 21, thereby preventing the electrolyte from leaking to the outside.

[0059] <Method of Assembling Water Electrolysis Cell> FIGS. 7 to 10 are explanatory views showing a method of assembling a water electrolysis cell.

[0060] As shown in Figures 6 and 7, after the insulating material 35 (see Figure 2 for both) is placed on the end plate 37, the insulator 31 is placed on top. The end plate 37, the insulating material 35, and the insulator 31 have through holes 71, 72, 73, and 74. The insulator 31 has the power feeder 33 in its center, and a seal member 114 is provided around the power feeder 33. Next, the metal plate 45 is placed on the insulator 31 so as to cover the power feeder 33, and manifold packings (seal members) are fitted into the through holes 72 and 74.

[0061] Next, as shown in Fig. 6 and Fig. 8 , the cathode side header 42 is placed on a metal plate 45, and the cathode side separator body 41 is attached to the opening 52 of the cathode side header 42. In addition, a seal member 117 is attached to the outside of the cathode side header 42. Then, as shown in Fig. 6 and Fig. 9 , the cathode side catalyst layer 22, cathode side current collector 24, ion exchange membrane 21, anode side catalyst layer 23, and anode side current collector 25 are stacked on the cathode side separator body 41.

[0062] Finally, as shown in Fig. 6 and Fig. 10 , the anode side header 44 is placed, and the anode side separator body 43 is attached to the opening 62 of the anode side header 44. A seal member 39 is attached to the outside of the anode side header 44. At this point, stacking of the first layer is completed. For the second and subsequent layers, a metal plate 45, cathode side header 42, cathode side separator body 41, cathode side catalyst layer 22, cathode side current collector 24, ion exchange membrane 21, anode side catalyst layer 23, anode side current collector 25, anode side header 44, anode side separator body 43, etc. are stacked in a similar manner.

[0063] Then, the insulator 32, the power supply 34, the insulating material 36, and the end plate 38 are placed on top of each other. The water electrolysis cell 10 is assembled by fastening the components together with a plurality of bolts.

[0064] [Effects of the present embodiment] The separator according to the first aspect is a separator 11, 12 used in a water electrolysis apparatus that uses an ion exchange membrane 21, and includes a separator body 41, 43 having a plurality of flow path grooves 51, 61 formed on a surface thereof, and a header 42, 44 having an opening 52, 62 for arranging the separator body 41, 43 formed in a central portion thereof, an electrolyte solution supply hole 53, 63 formed on one side of the flow path groove 51, 61, and a gas discharge hole 55, 65 formed on the other side thereof, and the separator body 41, 43 and the header 42, 44 are provided separately and are made of different materials.

[0065] According to the separator of the first aspect, by forming the separator bodies 41, 43 and the headers 42, 44 separately from each other and using different materials, it is possible to appropriately provide the plurality of flow path grooves 51, 61 in the separator bodies 41, 43, and to form the headers 42, 44 with high precision and without distortion. As a result, it is possible to improve sealing performance. Furthermore, by forming the separator bodies 41, 43 and the headers 42, 44 separately from each other, it is possible to freely set the height of the headers 42, 44.

[0066] The separator according to the second aspect is the separator according to the first aspect, except that the separator bodies 41, 43 are made of a metal material and the headers 42, 44 are made of a resin material. By forming the headers 42, 44 from a resin material, no metal members are disposed near the electrolyte solution supply holes 53, 63, which makes it possible to suppress the occurrence of leakage current and the decrease in electrolysis efficiency.

[0067] A separator according to a third aspect is the separator according to the first or second aspect, and further, the headers 42, 44 are formed of aramid fiber reinforced resin, which reduces the solubility of the headers 42, 44 in the electrolyte and improves the strength of the headers 42, 44.

[0068] A separator according to a fourth aspect is the separator according to any one of the first to third aspects, further comprising: a cathode side separator 11 having a cathode side separator body 441 and a cathode side header 42; and an anode side separator 12 having an anode side separator body 43 and an anode side header 44, wherein at least one opposing surface of the cathode side header 42 and the anode side header 44 is provided with a recess (first recess) 111 that accommodates a seal member (first seal portion) 39. This enables the seal member 39 to suppress leakage of the electrolyte between the cathode side separator 11 and the anode side separator 12.

[0069] A separator according to a fifth aspect is the separator according to the fourth aspect, further comprising: a cathode side separator body 41 and an anode side separator body 43 each having a corrugated shape and disposed on either side via a metal plate 45. This enables the metal plate 45 to improve the strength of the cathode side separator body 41 and the anode side separator body 43.

[0070] A separator according to a sixth aspect is the separator according to the fifth aspect, further comprising: a recess (second recess) 112 for accommodating a metal plate 45 on at least one opposing surface of the cathode side header 42 or the anode side header 44. This allows the metal plate 45 to be appropriately accommodated inside the cathode side header 42 or the anode side header 44.

[0071] A separator according to a seventh aspect is the separator according to the sixth aspect, further comprising: one of the cathode side header 42 and the anode side header 44 provided with a recess 112 and also provided with a recess (third recess) 113 for accommodating a seal member (second seal portion) 114 disposed between the header and the metal plate 45. This allows the seal member 114 to be appropriately accommodated in the header for suppressing leakage of the electrolyte from between the cathode side header 42 or the anode side header 44 and the metal plate 45.

[0072] A separator according to an eighth aspect is the separator according to any one of the fourth to seventh aspects, further comprising: the other of the cathode side header 42 and the anode side header 44 has an electrolytic solution supply portion and a gas and electrolytic solution discharge portion provided on one surface thereof, and a recess (fourth recess) 115 provided around the openings 52, 62 on the other surface thereof for accommodating the ion exchange membrane 21, the catalyst layers 22, 23, and the power feeders 24, 25. This allows the ion exchange membrane 21, the catalyst layers 22, 23, and the power feeders 24, 25 to be appropriately accommodated in the recess 115.

[0073] A separator according to a ninth aspect is the separator according to the eighth aspect, further comprising: a recess (fifth recess) 116 provided on the other surface around the recess 115 for accommodating a seal member (third seal portion) 117 to be placed between the other header and the ion exchange membrane 21. This makes it possible to appropriately accommodate the seal member 117 for suppressing leakage of the electrolyte from between the cathode side header 42 or the anode side header 44 and the ion exchange membrane 21.

[0074] The water electrolysis cell according to the tenth aspect comprises an ion exchange membrane 21, a cathode-side catalyst layer 22 and an anode-side catalyst layer 23 disposed on either side of the ion exchange membrane 21, a cathode-side power feeder 24 and an anode-side power feeder 25 disposed outside the cathode-side catalyst layer 22 and the anode-side catalyst layer 23, and a cathode-side separator 11 and an anode-side separator 12 disposed outside the cathode-side power feeder 24 and the anode-side power feeder 25. This enables the cathode-side separator 11 and the anode-side separator 12 to be formed with high precision, thereby improving sealing performance.

[0075] A water electrolysis cell according to an eleventh aspect is the water electrolysis cell according to the tenth aspect, further comprising a recess 115 provided on at least one of the opposing surfaces of the cathode side separator 11 and the anode side separator 12 to accommodate the ion exchange membrane 21, the cathode side catalyst layer 22, the anode side catalyst layer 23, the cathode side current collector 24, and the anode side current collector 25. This allows the recess 115 to appropriately accommodate the ion exchange membrane 21, the cathode side catalyst layer 22, the anode side catalyst layer 23, the cathode side current collector 24, and the anode side current collector 25.

[0076] REFERENCE SIGNS LIST 10 Water electrolysis cell 11 Cathode side separator 12 Anode side separator 13 Membrane electrode assembly 14 Power supply unit 21 Ion exchange membrane 22 Cathode side catalyst layer 23 Anode side catalyst layer 24 Cathode side power supply 25 Anode side power supply 31, 32 Insulators 33, 34 Power supply 35, 36 Insulator 37, 38 End plate 39 Seal member (first seal portion) 41 Cathode side separator body 42 Cathode side header 43 Anode side separator body 44 Anode side header 45 Metal plate 51, 61 Flow path groove 52, 62 Opening 53, 63 Electrolyte solution supply hole 54, 64 Aqueous solution flow section 55 Hydrogen gas discharge hole 56 Hydrogen gas flow section 57, 67 Electrolyte solution supply hole 58 Oxygen gas exhaust hole 65 Oxygen gas exhaust hole 66 Oxygen gas flow portion 68 Hydrogen gas exhaust hole 102 Sealing member 111 Recess (first recess) 112 Recess (second recess) 113 Recess (third recess) 114 Sealing member (second sealing portion) 115 Recess (fourth recess) 116 Recess (fifth recess) 117 Sealing member (third sealing portion)

Claims

1. A separator for use in a water electrolysis system that utilizes an ion exchange membrane, comprising: a separator body having a plurality of flow path grooves on its surface; and a header having an opening in its center for arranging the separator body, an electrolyte supply section on one side of the flow path grooves, and a gas and electrolyte discharge section on the other side, wherein the separator body and the header are provided separately and are made of different materials.

2. The separator according to claim 1, wherein the separator body is made of a metal material and the header is made of a resin material.

3. The separator according to claim 2, wherein the header is formed from an aramid fiber reinforced resin.

4. The separator according to claim 1, comprising a cathode side separator having a cathode side separator body and a cathode side header, and an anode side separator having an anode side separator body and an anode side header, wherein a first recess that accommodates a first seal portion is provided on at least one opposing surface of the cathode side header and the anode side header.

5. The separator according to claim 4, wherein the cathode side separator body and the anode side separator body have a corrugated shape and are disposed on either side with a metal plate interposed therebetween.

6. The separator according to claim 5, wherein a second recess for accommodating the metal plate is provided on at least one of the opposing surfaces of the cathode side header and the anode side header.

7. The separator according to claim 6, wherein one of the cathode side header and the anode side header is provided with the second recess and also with a third recess that accommodates a second seal portion that is disposed between the header and the metal plate.

8. The separator according to claim 7, wherein the other of the cathode side header and the anode side header has the electrolytic solution supply section and the gas and electrolytic solution discharge section provided on one surface, and a fourth recess that houses the ion exchange membrane, catalyst layer, and power supply body provided around the opening on the other surface.

9. The separator according to claim 8, wherein the other header has a fifth recess provided around the fourth recess on the other surface thereof for accommodating a third seal portion disposed between the header and the ion exchange membrane.

10. A water electrolysis cell comprising: an ion exchange membrane; a cathode-side catalyst layer and an anode-side catalyst layer disposed on either side of the ion exchange membrane; a cathode-side current feeder and an anode-side current feeder disposed outside the cathode-side catalyst layer and the anode-side catalyst layer; and the separators according to claim 1 used as a cathode-side separator and an anode-side separator disposed outside the cathode-side current feeder and the anode-side current feeder.

11. The water electrolysis cell according to claim 10, wherein at least one of the opposing surfaces of the cathode side separator and the anode side separator is provided with a recess for accommodating the ion exchange membrane, the cathode side power supply element, the anode side power supply element, the cathode side catalyst layer, and the anode side catalyst layer.

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