Separator, electrolysis cell, and hydrogen production device

Abstract

This separator is used in an electrolysis cell that produces hydrogen from water contained in a conductive fluid, and comprises a plate-like main body. The main body comprises: an electrolysis region which is disposed in a central part of a first surface of the main body; a manifold which is formed in an outer peripheral part that surrounds the central part on the first surface, and which penetrates the main body; and a flow path which connects the electrolysis region and the manifold to each other. The flow path comprises a tunnel part which is connected to the inner circumferential surface of the manifold inside the main body.

Description

Separators, electrolytic cells, and hydrogen production equipment 【0001】 This disclosure relates to separators, electrolytic cells, and hydrogen production equipment. 【0002】 Patent Document 1 discloses a water electrolysis apparatus for producing hydrogen by electrolyzing an alkaline aqueous solution, which is a conductive fluid. The water electrolysis apparatus comprises a stack of multiple electrolytic cells, which are water electrolysis electrochemical cells. Each water electrolysis electrochemical cell comprises an anode, a cathode, an electrolyte membrane, an anode separator, and a cathode separator. The anode has an anode catalyst layer and a porous anode power supply. The cathode has a cathode catalyst layer and a porous cathode power supply. In each water electrolysis electrochemical cell, the anode separator, anode power supply, anode catalyst layer, electrolyte membrane, cathode catalyst layer, cathode power supply, and cathode separator are arranged in this order. 【0003】 Anode separators and cathode separators are separators with the same structure. A separator has a supply manifold, a discharge manifold, and a flow path. The flow path has a first connecting passage connected to the supply manifold, a second connecting passage connected to the discharge manifold, and an electrode passage connecting the first and second connecting passages. The electrode passage is the region in the separator where the power supply is located, and is the electrolytic region where current flows in a direction along the thickness of the separator during operation of the electrolytic cell. The alkaline aqueous solution is supplied to the anode and cathode through the supply manifold, the first connecting passage, and the electrode passage. The alkaline aqueous solution that has passed through the anode and cathode is discharged from the discharge manifold through the second connecting passage. In the electrolytic cell, a surface sealing material is placed on the outer circumference surrounding the electrode passage in the separator. The surface sealing material prevents leakage of conductive fluid from inside the electrolytic cell. 【0004】 In the electrochemical cell for water electrolysis described above, when an alkaline aqueous solution is supplied to the anode and cathode, and a voltage is applied between the anode and cathode, a chemical reaction occurs in which oxygen is produced at the anode and hydrogen is produced at the cathode. 【0005】 Japanese Patent Publication No. 2023-73782 【0006】 The separator of this disclosure is used in an electrolytic cell for producing hydrogen from water contained in a conductive fluid, and comprises a plate-shaped body. The body comprises an electrolytic region located in the center of a first surface of the body, a manifold formed on the outer periphery surrounding the central portion of the first surface and penetrating the body, and a flow path connecting the electrolytic region and the manifold. The flow path comprises a tunnel portion inside the body that connects to the inner circumferential surface of the manifold. 【0007】 Figure 1 is a schematic diagram of the hydrogen production apparatus according to Embodiment 1. Figure 2 is an exploded perspective view illustrating the basic configuration of the electrolytic cell according to Embodiment 1. Figure 3 is a schematic configuration diagram of the cell module according to Embodiment 1. Figure 4 is a schematic plan view of the first surface of the separator according to Embodiment 1. Figure 5 is a schematic plan view of the second surface of the separator in Figure 4. Figure 6 is a partial cross-sectional view of the electrolytic cell of Embodiment 1, cut at the position of the VI-VI cross-section in Figure 4. Figure 7 is a schematic plan view of the first surface of the separator according to Embodiment 2. Figure 8 is a partial cross-sectional view of the electrolytic cell according to Embodiment 3. Figure 9 is a cross-sectional view of Figure 8 taken along the IX-IX line. Figure 10 is a partial cross-sectional view of the separator according to Embodiment 4. 【0008】 [Problems this disclosure aims to solve] In conventional separators, the communication path is a groove-shaped channel formed on the surface of the separator. The opening of the channel is covered with a surface sealing material. The surface sealing material is a frame-shaped insulating member that insulates between adjacent separators. During operation of the electrolytic cell, this frame-shaped insulating member may fall into the channel due to the pressure difference between the anode and cathode. If the insulating member falls into the channel, the flow of conductive fluid and gas in the channel may be obstructed, and the amount of conductive fluid and gas flowing may decrease. When the amount of conductive fluid and gas flowing decreases, the electrolysis efficiency of the electrolytic cell decreases. Electrolysis efficiency is the ratio of the amount of electricity that contributed to hydrogen production when the total amount of electricity supplied to the electrolytic cell is set to 100%. 【0009】If a frame-shaped insulating component falls into the flow path, one might consider increasing the output of the pump that circulates the conductive fluid in order to increase the flow rate of conductive fluid and gas in the electrolytic cell. However, increasing the pump output may actually decrease the electrolysis efficiency due to the increased power consumption of the pump. In addition, the internal pressure of the electrolytic cell may become too high, potentially damaging the electrolytic cell. 【0010】 One of the objectives of this disclosure is to provide a separator that can prevent a frame-shaped insulating member from falling into a flow path in an electrolytic cell. 【0011】 [Description of Embodiments of the Disclosure] First, embodiments of the Disclosure will be listed and described. 【0012】 <1> A separator according to one embodiment of the present disclosure is a separator used in an electrolytic cell for producing hydrogen from water contained in a conductive fluid, and comprises a plate-shaped body. The body comprises an electrolytic region disposed in the center of a first surface of the body, a manifold formed on the outer periphery surrounding the central portion of the first surface and penetrating the body, and a flow path connecting the electrolytic region and the manifold. The flow path comprises a tunnel portion inside the body that connects to the inner circumferential surface of the manifold. 【0013】 In the electrolytic cell using the above-described separator, a conductive porous layer is arranged in the electrolytic region of the separator body. That is, the electrolytic region of the body is the region in which current flows in a direction along the thickness of the separator when the electrolytic cell using the separator is in operation, and is the region facing the reaction field where the chemical reaction in the electrolytic cell takes place. A recess may or may not be formed in this electrolytic region. The recess may be, for example, a depression large enough to fit the porous layer, or it may be a plurality of grooves configured for the flow of a conductive fluid. An electrolytic region in which no recess is formed is simply a flat surface flush with the first surface. 【0014】In the above separator, at least a portion of the flow path connecting the electrolytic region and the manifold is formed by a tunnel section located inside the main body. In other words, the tunnel section is not exposed on the first surface of the main body. The tunnel section is not blocked by an insulating material located on the first surface of the separator. Therefore, the flow rate of conductive fluid and gas in the flow path is less likely to decrease, and a decrease in electrolytic efficiency due to a decrease in the flow rate of conductive fluid and gas, as well as damage to the electrolytic cell due to an increase in the internal pressure of the electrolytic cell, are less likely to occur. 【0015】 <2> In the separator described in <1> above, the main body may include a first plate material having the first surface and a second plate material having a second bonding surface that is bonded to a first bonding surface on the opposite side of the first surface of the first plate material. The tunnel portion is composed of an internal space of a bypass hole penetrating the first plate material and an internal space of a bypass groove formed on at least one of the first bonding surface and the second bonding surface, which connects the manifold and the bypass hole. 【0016】 In the configuration described in <2> above, the main body having a tunnel section can be manufactured by bonding the first plate material and the second plate material together. Bypass holes penetrating the first plate material in the thickness direction can be easily formed using a general-purpose drill or the like. Bypass grooves arranged on the joint surfaces of the first plate material and the second plate material can also be easily formed using general-purpose grooving tools. 【0017】 <3> In the separator described in <1> or <2> above, the main body may include a surface groove extending from the opening edge of the manifold on the first surface toward the electrolytic region, and a trough-shaped or pipe-shaped attachment member fitted into the surface groove. The tunnel portion is formed by the internal space of the attachment member. 【0018】 In the configuration described in <3> above, a main body having a tunnel section can be manufactured by fitting an attachment member into a surface groove located on the first surface of the main body. The surface groove located on the first surface of the main body can be easily formed using a general-purpose groove machining tool. 【0019】<4> In the separator described in any of <1> to <3> above, when the first surface is viewed from above, the maximum width of the opening in the tunnel portion may be less than or equal to the length of the adjacent edge of the electrolytic region. The adjacent edge is the edge of the outer periphery of the electrolytic region that is close to the manifold. 【0020】 The manifold is a supply manifold that supplies conductive fluid to the electrolytic region, or a discharge manifold that recovers only gas, or conductive fluid and gas, from the electrolytic region. The adjacent edge is a supply edge adjacent to the supply manifold in the electrolytic region, or a discharge edge adjacent to the discharge manifold in the electrolytic region. The configuration of <4> above includes configuration 1 in which the maximum width of the opening of the tunnel section connected to the supply manifold is less than or equal to the length of the supply edge, configuration 2 in which the maximum width of the opening of the tunnel section connected to the discharge manifold is less than or equal to the length of the discharge edge, and configurations that satisfy both configuration 1 and configuration 2. 【0021】 When conductive fluid is supplied in parallel from a common source to multiple electrolytic cells, a self-discharge current flows through the conductive fluid in the flow path according to the potential difference between each electrolytic cell. This self-discharge current is called a shunt current. When a shunt current flows in an electrolytic cell, the electrolysis efficiency of the electrolytic cell decreases. The above-mentioned shunt current can be reduced if the maximum width of the opening in the tunnel section is less than or equal to the length of the adjacent edge. 【0022】 <5> In the separator described in any of <1> to <4> above, the flow cross-sectional area of ​​the tunnel portion may be less than or equal to the flow cross-sectional area of ​​the manifold. 【0023】 If the cross-sectional area of ​​the flow path in the tunnel section is less than or equal to the cross-sectional area of ​​the flow path in the manifold, the above-mentioned shunt current can be reduced. 【0024】 <6> In the separator described in any of <1> to <5> above, the end of the tunnel portion may open to the inner circumferential surface of the manifold. 【0025】 The opening at the end of the tunnel section to the inner surface of the manifold allows for smooth flow of conductive fluids and gases between the manifold and the tunnel section. 【0026】<7> In the separator described in any of <1> to <6> above, the flow path may include a rectifier that runs along the adjacent edge of the electrolytic region and is connected to the adjacent edge. The adjacent edge is the edge of the outer periphery of the electrolytic region that is close to the manifold. 【0027】 The rectifier section connected to the supply edge, which is the proximity edge to the supply manifold, rapidly diffuses the conductive fluid into the electrolytic region. This facilitates the chemical reaction in the electrolytic region. The rectifier section connected to the discharge edge, which is the proximity edge to the discharge manifold, rapidly recovers the conductive fluid and gas from the electrolytic region. This ensures smooth flow of the conductive fluid and gas in the electrolytic region. 【0028】 <8> In the separator described in any of <1> to <7> above, the main body may be a metal plate or a plate made of a composite material including a conductive material and a resin. 【0029】 Metal plates offer excellent rigidity. Therefore, even when conductive fluid is circulated through the electrolytic cell at high pressure, the separator is less likely to deform. Furthermore, fluid leakage due to deformation is less likely. The main body, made of composite materials, offers excellent productivity because manifolds and other components can be formed by mold molding. 【0030】 <9> The separator described in <8> above may be provided with an insulating layer that covers the inner surface of the manifold and the inner surface of the tunnel portion. 【0031】 If an insulating layer is formed on the inner circumferential surface of the manifold and tunnel sections where the conductive fluid comes into contact, the shunt current will be less likely to flow. As a result, the electrolysis efficiency of the electrolytic cell will not decrease as easily. 【0032】 <10> An electrolytic cell according to one embodiment of the present disclosure comprises an anode section through which a conductive fluid flows, a cathode section through which hydrogen is produced from water contained in the conductive fluid, and an electrolyte membrane separating the anode section and the cathode section. The anode section comprises a separator according to any one of <1> to <9> above, and a frame-shaped insulating member disposed on the first surface of the separator. 【0033】The insulating member is, for example, a flexible gasket. The gasket can insulate between the separator and the electrolyte membrane while sealing between the separator and the electrolyte membrane. The insulating member may also be a protective plate with a higher Young's modulus than the gasket. The protective plate is a member for mechanically protecting the electrolyte membrane from members that can contact the electrolyte membrane such as the separator, and has rigidity that can maintain a frame shape without support. 【0034】 The electrolytic cell includes a separator having a tunnel portion. The tunnel portion is not blocked by a frame-shaped insulating member disposed on the first surface of the separator. Therefore, the flow rates of the conductive fluid and the gas in the flow path are not easily reduced, and it is difficult for problems such as a decrease in electrolysis efficiency due to a decrease in the flow rates of the conductive fluid and the gas, and damage to the electrolytic cell due to an increase in the internal pressure of the electrolytic cell to occur. 【0035】 <11> In the electrolytic cell according to <10> above, the material of the insulating member may be a polymer material. 【0036】 Since the polymer material is excellent in flexibility, it is easy to reduce liquid leakage from the electrolytic cell. Also, when the insulating member contacts the electrolyte membrane, the electrolyte membrane is not easily damaged by the insulating member. 【0037】 <12> In the electrolytic cell according to <10> or <11> above, the conductive fluid may be an aqueous alkaline solution, and the electrolyte membrane may be an anion exchange membrane. 【0038】 In an aqueous alkaline solution, the electrolysis of water is promoted as compared with the case where the fluid supplied to the electrolytic cell is water. 【0039】 <13> In the electrolytic cell according to <12> above, when the total amount of the aqueous alkaline solution is 100% by mass, the concentration of the electrolyte contained in the aqueous alkaline solution may be 0.1% by mass or more. 【0040】 If the concentration of the electrolyte contained in the aqueous alkaline solution is 0.1% by mass or more, the electrolysis of water is easily promoted. 【0041】 <14> In the electrolytic cell according to any one of <10> to <13> above, the temperature of the conductive fluid in the anode portion may be 45°C or higher and 80°C or lower. 【0042】 If the temperature of the conductive fluid in the anode part is 45°C or higher, the electrolysis of water is likely to be promoted. If the temperature of the conductive fluid in the anode part is 80°C or lower, the constituent materials of the anode part are less likely to undergo thermal degradation. 【0043】 <15> The hydrogen production device according to one embodiment of the present disclosure includes a cell module in which a plurality of electrolytic cells are connected in series, and each of the plurality of electrolytic cells is the electrolytic cell according to any one of <10> to <14> above. 【0044】 Since the hydrogen production device includes the electrolytic cell of the present disclosure with excellent electrolysis efficiency, hydrogen can be produced efficiently. 【0045】 [Details of Embodiments of the Present Disclosure] Hereinafter, specific examples of the separator, electrolytic cell, and hydrogen production device of the present disclosure will be described based on the drawings. The same reference numerals in the figures denote the same objects. The shapes, sizes, positional relationships, etc. shown in each figure are presented for the purpose of clarifying the description and do not necessarily represent the actual shapes, sizes, positional relationships, etc. Note that the present invention is not limited to the configurations shown in the embodiments, but is intended to be indicated by the claims and to include all modifications within the meaning and scope equivalent to the claims. 【0046】 [Embodiment 1] In Embodiment 1, first, an overview of a hydrogen production device including an electrolytic cell will be described. Next, the basic configuration of the electrolytic cell and a cell module in which a plurality of electrolytic cells are connected in series will be described. Based on that description, the separator provided in the electrolytic cell will be described. 【0047】 <Hydrogen Production Device> The hydrogen production device 100 in FIG. 1 includes an electrolytic cell 1, a circulation mechanism 8, and a DC power source 9. The electrolytic cell 1 includes an electrolyte membrane 2, an anode part 3, and a cathode part 4. The electrolyte membrane 2 in this example is an anion exchange membrane (AEM: Anion Exchange Membrane). The AEM allows hydroxide ions (OH －) allows movement. In other words, the hydrogen production apparatus 100 in this example is an AEM type hydrogen production apparatus. Although simplified in Figure 1, the anode section 3 comprises a first catalyst layer 30 and a first separator 31, and the cathode section 4 comprises a second catalyst layer 40 and a second separator 41. 【0048】 The fluid flow mechanism 8 in this example includes an anode supply pipe 81 for supplying conductive fluid to the anode 3, an anode discharge pipe 83 for discharging conductive fluid from the anode 3, and a cathode discharge pipe 85 for discharging hydrogen from the cathode 4. Unlike this example, a cathode supply pipe for supplying conductive fluid to the cathode 4 may also be provided. The DC power supply 9 applies a DC voltage between the anode 3 and the cathode 4. The high-potential electrode of the DC power supply 9 is connected to the anode 3, and the low-potential electrode of the DC power supply 9 is connected to the cathode 4. 【0049】 The conductive fluid in this example is an alkaline aqueous solution. The alkaline aqueous solution is, for example, an aqueous solution of potassium hydroxide or sodium bicarbonate. Compared to the case where the fluid supplied to the electrolytic cell 1 is pure water, the electrolysis of water is accelerated when an alkaline aqueous solution is used. The concentration of the electrolyte in the alkaline aqueous solution is, for example, 0.1% by mass or more and 10% by mass or less, when the total alkaline aqueous solution is considered to be 100% by mass. The electrolyte concentration may also be 0.5% by mass or more and 8% by mass or less, or 1.0% by mass or more and 6.0% by mass or less. The pH of the alkaline aqueous solution is, for example, 8 or more and 15 or less. The pH of the alkaline aqueous solution may also be 10 or more and 14.3 or less. The electrical conductivity of the alkaline aqueous solution is, for example, 0.003 mS / cm or more and 500 mS / cm or less. The electrical conductivity of the alkaline aqueous solution may also be 0.01 mS / cm or more and 400 mS / cm or less, or 0.02 mS / cm or more and 300 mS / cm or less. 【0050】 The conductive fluid of the alkaline aqueous solution is supplied to the anode section 3 from the anode supply pipe 81. In this example, the conductive fluid is not supplied to the cathode section 4. H is supplied from the anode section 3 to the cathode section 4 through the electrolyte membrane 2. ２O moves. When a voltage is applied between the anode part 3 and the cathode part 4 by the DC power source 9, the following chemical reactions occur in the first catalyst layer 30 of the anode part 3 and the second catalyst layer 40 of the cathode part 4. Anode part 3: 4OH － →2H ２ O + O ２ + 4e － Cathode part 4: 4H ２ O + 4e － →2H ２ + 4OH － 【0051】 As shown in the above chemical formulas, in the anode part 3, water (H ２ O) and oxygen (O ２ ) are produced from hydroxide ions, and electrons are released. In the cathode part 4, water and electrons combine to produce hydrogen (H ２ ) and hydroxide ions. The hydroxide ions produced in the cathode part 4 move through the electrolyte membrane 2, which is an AEM, to the anode part 3. The oxygen produced in the anode part 3 is discharged to the outside of the electrolytic cell 1 from the anode discharge pipe 83 together with the alkaline aqueous solution. The hydrogen produced in the cathode part 4 is discharged to the outside of the electrolytic cell 1 from the cathode discharge pipe 85. 【0052】 The temperature of the conductive fluid in the anode part 3 is, for example, 45°C or higher and 80°C or lower. If the temperature of the conductive fluid is 45°C or higher, the electrolysis of water is likely to be promoted. If the temperature of the conductive fluid is 80°C or lower, the constituent materials of the anode part 3 are less likely to undergo thermal degradation. The temperature of the conductive fluid may also be 50°C or higher and 75°C or lower. 【0053】 <Electrolytic cell> A more detailed configuration of the electrolytic cell 1 will be described based on FIG. 2. As shown in the exploded perspective view of FIG. 2, the anode part 3 of the electrolytic cell 1 includes a first catalyst layer 30, a first separator 31, a first porous layer 32, and a first insulating member 33. 【0054】 The first catalyst layer 30 is in contact with or close to the first surface 21 of the electrolyte membrane 2. The first catalyst layer 30 promotes the chemical reaction in the anode part 3. As the catalyst contained in the first catalyst layer 30, known ones such as noble metals, metal oxides, or those in which these are supported on carbon or the like can be used. 【0055】 The first separator 31 is a conductive plate material facing the first surface 21 of the electrolyte membrane 2. The first separator 31 has the function of partitioning the section through which the fluid supplied to the anode 3 flows. The first separator 31 also has the function of applying voltage to the electrolytic cell 1. 【0056】 The first porous layer 32 is a conductive porous material. The first porous layer 32 has the function of diffusing a conductive fluid throughout the entire internal space of the anode portion 3. 【0057】 The first insulating member 33 is an insulating frame. The first insulating member 33 has the function of insulating the space between the first separator 31 and the electrolyte membrane 2. The first insulating member 33 also has the function of preventing the first separator 31 from directly contacting the electrolyte membrane 2 and mechanically protecting the electrolyte membrane 2. 【0058】 The first insulating member 33 is formed of, for example, a polymer material. The polymer material is, for example, a rubber material or resin material having at least one of alkali resistance and heat resistance in addition to electrical insulation. A rubber material or resin material having alkali resistance is a rubber material or resin material that has resistance to conductive fluids with a pH of 8 or higher. A rubber material or resin material having heat resistance is a rubber material or resin material that has resistance to temperatures of 80°C or lower. 【0059】Examples of rubber materials include natural rubber, styrene-butadiene rubber, chloroprene rubber, butadiene rubber, acrylonitrile-butadiene rubber, silicone rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, fluororubber, isobutylene-isoprene rubber, urethane rubber, or chlorosulfonated polyethylene rubber. Examples of resin materials include epoxy resin, polyamide-imide resin, polypropylene resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl alcohol resin, polystyrene resin, polyisobutylene resin, polyoxymethylene resin, acrylic resin, polyphenol resin, fluororesin, polyamide resin, acrylonitrile-butadiene-styrene resin, polyethylene resin, polyester resin, diacetate resin, triacetate resin, polyphenylsulfone resin, polyethylene terephthalate resin, polytetrafluoroethylene resin, polycarbonate resin, polyvinyl acetate resin, polyacetal resin, furan resin, polyurethane resin, melamine resin, polyetheretherketone, diallyl phthalate resin, unsaturated polyester resin, ethylene-vinyl acetate copolymer resin, polymethylpentene resin, cellulose acetate, or nylon resin. 【0060】 The cathode section 4 of the electrolytic cell 1 comprises a second catalyst layer 40, a second separator 41, a second porous layer 42, and a second insulating member 43. The second catalyst layer 40 is in contact with or close to the second surface 22 of the electrolyte membrane 2 and promotes the chemical reaction in the cathode section 4. Known catalysts such as noble metals, metal oxides, or those supported on carbon or the like can be used as catalysts in the second catalyst layer 40. 【0061】 The second separator 41 is a conductive plate material facing the second surface 22 of the electrolyte membrane 2. The second separator 41 has the function of partitioning the space through which the fluid flows in the cathode section 4. The second separator 41 also has the function of applying voltage to the electrolytic cell 1. 【0062】 The second porous layer 42 is a conductive porous material. The second porous layer 42 functions as a channel for hydrogen produced in the cathode section 4. 【0063】The second insulating member 43 is an insulating frame. The second insulating member 43 has the function of insulating the space between the second separator 41 and the electrolyte membrane 2. The second insulating member 43 is formed of, for example, a polymer material. The polymer material is, for example, the polymer material described in the section on the first insulating member 33. 【0064】 The first catalyst layer 30, the electrolyte membrane 2, and the second catalyst layer 40 may be joined together to form a catalytic coated membrane (CCM). The first porous layer 32, the first catalyst layer 30, the electrolyte membrane 2, the second catalyst layer 40, and the second porous layer 42 may be joined together to form a membrane electrode assembly (MEA). 【0065】 <Cell Module> The hydrogen production apparatus 100 typically includes a cell module 10 in which multiple electrolytic cells 1 are electrically connected in series, as shown in Figure 3. In Figure 3, only a portion of the multiple electrolytic cells 1 are shown. For the left electrolytic cell 1, only the second insulating member 43, the second porous layer 42, and the electrolyte membrane 2 are shown. For the right electrolytic cell 1, only the first insulating member 33, the first porous layer 32, and the electrolyte membrane 2 are shown. In the cell module 10, two adjacent electrolytic cells 1 are separated by a separator 5. In this example, the separator 5 combines the functions of both the first separator 31 and the second separator 41. That is, the first surface 5a of the separator 5 facing to the right in Figure 3 constitutes part of the anode portion 3, and the second surface 5b of the separator 5 facing to the left in Figure 3 constitutes part of the cathode portion 4. 【0066】 In the cell module 10 of this example, the first porous layer 32 of the anode portion 3 is fitted into a recess 50c formed on the first surface 5a of the separator 5. The first insulating member 33 is sandwiched between the first surface 5a of the separator 5 and the electrolyte membrane 2. The electrolyte membrane 2 is protected from the separator 5 by the first insulating member 33. 【0067】In the cell module 10 of this example, the second porous layer 42 of the cathode portion 4 is fitted into a recess 59c formed on the second surface 5b of the separator 5. The second insulating member 43 is sandwiched between the second surface 5b of the separator 5 and the electrolyte membrane 2. The electrolyte membrane 2 is protected from the separator 5 by the second insulating member 43. 【0068】 <Separator> The separator 5 in this example comprises a plate-shaped body 5P, as shown in Figures 4 to 6. The body 5P is a single molded product that can be divided into a central portion 5α including the area center of the body 5P and an outer peripheral portion 5β surrounding the central portion 5α. As will be described later, the central portion 5α forms an electrolytic region 50. In other words, the electrolytic region 50 is formed by a part of the body 5P. The body 5P in this example is formed of a conductive plate. 【0069】 In this example, the main body 5P is, for example, a metal plate. The material of the metal plate is, for example, one or more selected from the group consisting of iron alloys, titanium, titanium alloys, copper, copper alloys, nickel, nickel alloys, aluminum, aluminum alloys, and zinc. Iron alloys are, for example, steel. Steel is various types of steel such as stainless steel, silicon chromium steel, or carbon steel. Metal plates have excellent rigidity. Therefore, even if a conductive fluid is circulated through the electrolytic cell 1 at high pressure, the separator 5 is less likely to deform. The main body 5P may also comprise a metal plate and a coating layer made of a material with better oxidation resistance than the metal plate. The material of the coating layer is, for example, one or more selected from the group consisting of platinum group metals, gold, silver, and nickel. 【0070】The main body 5P may be a plate made of a composite material containing a conductive material and a resin. The conductive material may be a metal or a nonmetal. Examples of metals are those listed as materials for metal plates. Examples of nonmetals are carbon materials. Examples of carbon materials are graphite, carbon black, or diamond-like carbon. The resin material in the composite material is selected from the group consisting of polyethylene resin, polypropylene resin, polytetrafluoroethylene resin, perfluoroalkoxyalkane resin, perfluoroethylenepropene copolymer, and polyphenylene sulfide resin. The main body 5P made of the composite material has excellent productivity because it can easily form irregularities by mold molding. 【0071】 The separator 5 in this example includes a supply manifold 51, a discharge manifold 53, and an exhaust manifold 55 that penetrate the main body 5P at the outer circumference 5β. The supply manifold 51 is a conduit connected to the anode supply pipe 81 in Figure 1. The discharge manifold 53 is a conduit connected to the anode discharge pipe 83 in Figure 1. The exhaust manifold 55 is a conduit connected to the cathode discharge pipe 85 in Figure 1. Here, as shown in Figure 2, holes are formed in the electrolyte membrane 2, the first insulating member 33, and the second insulating member 43 at positions corresponding to the manifolds described above. 【0072】 An electrolytic region 50 is formed in the central part 5α of the first surface 5a of the main body 5P. The electrolytic region 50 is the region where the first porous layer 32 is arranged, as shown in Figure 3. That is, the electrolytic region 50 in the main body 5P is the region where current flows in a direction along the thickness of the separator 5 when the electrolytic cell 1 is in operation, and is the region facing the anode reaction field in the electrolytic cell 1. The anode reaction field is the three-dimensional region where the first catalyst layer 30 is arranged, that is, the three-dimensional region where the chemical reaction of the anode portion 3 occurs. To put it another way, the electrolytic region 50 is the region exposed from the window portion of the frame-shaped first insulating member 33 (Figures 2 and 3) in the electrolytic cell 1. In this example, the electrolytic region 50 has a recess 50c that is large enough to accommodate the first porous layer 32. In this example, the outer contour line of the electrolytic region 50 coincides with the outer contour line of the recess 50c. Unlike this example, the electrolytic region 50 may be a flat surface flush with the first surface 5a. 【0073】 The main body 5P is provided with a flow path 52 that connects the electrolytic region 50 and the supply manifold 51. The flow path 52 is a supply path that guides conductive fluid from the supply manifold 51 toward the electrolytic region 50. In the following description, the flow path 52 will be referred to as the supply path 52. In this example, the supply path 52 includes a tunnel section 52t and a flow straightening section 52r. When the first insulating member 33 is placed on top of the separator 5, the first insulating member 33 overlaps the supply path 52. That is, the supply path 52 is not exposed to the window portion of the first insulating member 33. 【0074】 As shown in Figure 6, the tunnel section 52t connects to the inner circumferential surface 511 of the supply manifold 51 inside the main body 5P. In other words, the first end of the tunnel section 52t opens in the middle of the supply manifold 51 in the direction along its length. The second end of the tunnel section 52t, opposite to the first end, connects to the flow straightening section 52r. The tunnel section 52t is a continuous cylindrical space from the opening at the first end to the opening at the second end. The conductive fluid supplied from the supply manifold 51 flows along this cylindrical space and does not leak from the tunnel section 52t. The specific configuration of the tunnel section 52t will be described later. 【0075】 As shown in Figure 4, the rectifier section 52r is a groove along the supply edge B1 in the electrolysis region 50, and communicates with the recess 50c of the electrolysis region 50 at the position of the supply edge B1. The supply edge B1 is the adjacent edge of the outer periphery of the electrolysis region 50 that is close to the supply manifold 51, and is the edge that serves as the inlet for the conductive fluid in the electrolysis region 50. In this example, the supply edge B1 is the lower edge of the rectangular recess 50c. The rectifier section 52r in this example is roughly triangular in shape with the supply edge B1 as its base. The second end of the tunnel section 52t opens at a position close to the vertex of the obtuse angle of this roughly triangular shape. Due to this rectifier section 52r, the conductive fluid flows into the electrolysis region 50 in a dispersed state along the supply edge B1 of the electrolysis region 50. Therefore, chemical reactions in the electrolysis region 50 are easily promoted. The rectifier section 52r is not an essential component. In a separator 5 that does not have a rectifier section 52r, the second end of the tunnel section 54t only needs to be connected to the vicinity of the supply edge B1 in the electrolytic region 50. 【0076】The main body 5P further includes a flow path 54 connecting the electrolysis region 50 and the discharge manifold 53. The flow path 54 is a discharge passage that guides conductive fluid and oxygen from the electrolysis region 50 toward the discharge manifold 53. In the following description, the flow path 54 will be referred to as the discharge passage 54. In this example, the discharge passage 54 includes a tunnel section 54t and a flow straightening section 54r. When the first insulating member 33 is placed on top of the separator 5, the first insulating member 33 overlaps the discharge passage 54. That is, the discharge passage 54 is not exposed to the window portion of the first insulating member 33. 【0077】 The configuration of tunnel section 54t is the same as that of tunnel section 52t. That is, tunnel section 54t is connected to the inner circumferential surface of the discharge manifold 53. In other words, the first end of tunnel section 54t opens in the middle of the direction along the length of the discharge manifold 53. The second end of tunnel section 54t, opposite to the first end, is connected to the flow straightening section 54r. Tunnel section 54t is a continuous cylindrical space from the opening at the first end to the opening at the second end. Conductive fluid and gas discharged from the discharge manifold 53 flow along the cylindrical space and do not leak from tunnel section 54t. 【0078】 The rectifier section 54r is a groove along the discharge edge B2 in the electrolysis region 50, and communicates with the recess 50c of the electrolysis region 50 at the location of the discharge edge B2. The discharge edge B2 is the adjacent edge of the outer periphery of the electrolysis region 50 that is close to the discharge manifold 53, and is the edge that serves as the outlet for the conductive fluid in the electrolysis region 50. In this example, the discharge edge B2 is the upper edge of the rectangular recess 50c. The rectifier section 54r in this example is roughly triangular in shape with the discharge edge B2 as its base. The second end of the tunnel section 54t opens at a position close to the vertex of the obtuse angle of this roughly triangular shape. This rectifier section 54r allows for the rapid recovery of the conductive fluid from the electrolysis region 50 along the entire length of the discharge edge B2, and facilitates the smooth flow of conductive fluid and gas in the electrolysis region 50. It also allows for the rapid recovery of oxygen produced in the anode section 3. The rectifier section 54r is not an essential component. In a separator 5 that does not have a rectifier section 54r, the second end of the tunnel section 54t only needs to be connected to the vicinity of the discharge edge B2 in the electrolytic region 50. 【0079】As shown in Figure 4, when the first surface 5a is viewed from above, the maximum widths of the openings A2 and A4 of the tunnel sections 52t and 54t may be less than or equal to the length of the adjacent edge of the electrolytic region 50. In other words, on the first surface 5a, the maximum width of the opening A2 of the tunnel section 52t may be less than or equal to the length of the supply edge B1 of the electrolytic region 50, and the maximum width of the opening A4 of the tunnel section 54t may be less than or equal to the length of the discharge edge B2 of the electrolytic region 50. With such a configuration, the shunt current in the electrolytic cell 1 is reduced. The above maximum width may be, for example, less than the length of the adjacent edge, or less than or equal to 1 / 2, 1 / 5, or 1 / 10 of the length of the adjacent edge. In this example, the maximum width of the opening A2 of the tunnel section 52t is less than or equal to 1 / 5 of the length of the supply edge B1. In this example, the maximum width of the opening A4 of the tunnel section 54t is less than or equal to 1 / 5 of the length of the discharge edge B2. 【0080】 The flow path cross-sectional area of ​​tunnel section 52t may be less than or equal to the flow path cross-sectional area of ​​supply manifold 51, and the flow path cross-sectional area of ​​tunnel section 54t may be less than or equal to the flow path cross-sectional area of ​​discharge manifold 53. With such a configuration, the shunt current in the electrolytic cell 1 is reduced. The flow path cross-sectional areas of tunnel section 52t and tunnel section 54t may be less than 100%, 80% or less, 70% or less, or 50% or less of the flow path cross-sectional areas of supply manifold 51 and discharge manifold 53, respectively. The flow path cross-sectional area is the area of ​​the cross-section perpendicular to the direction of fluid flow. 【0081】As shown in Figure 4, when the first surface 5a is viewed from above, the maximum widths of the openings A2 and A4 of the tunnel sections 52t and 54t may be less than or equal to the maximum widths of the openings A1 and A3 of the manifolds 51 and 53. In other words, on the first surface 5a, the maximum width of the opening A2 of the tunnel section 52t may be less than or equal to the maximum width of the opening A1 of the supply manifold 51, and the maximum width of the opening A4 of the tunnel section 54t may be less than or equal to the maximum width of the opening A3 of the discharge manifold 53. With such a configuration, the shunt current in the electrolytic cell 1 is reduced. The maximum widths of the openings A2 and A4 of the tunnel sections 52t and 54t may be less than 100%, 90% or less, or 80% or less of the maximum widths of the openings A1 and A3 of the manifolds 51 and 53. In this example, the maximum width of the opening A2 of the tunnel section 52t is 90% or less of the maximum width of the opening A1 of the supply manifold 51. In this example, the maximum width of the opening A4 of the tunnel section 54t is 90% or less of the maximum width of the opening A3 of the discharge manifold 53. In Figure 4, the maximum widths of the openings A1 and A3 of the manifolds 51 and 53 correspond to the diameters of the manifolds 51 and 53. 【0082】 As shown in Figure 5, an electrolytic region 59 is formed in the central part 5α of the second surface 5b of the main body 5P. The electrolytic region 59 is the region where the second porous layer 42 is arranged, as shown in Figure 3. That is, the electrolytic region 59 in the main body 5P is the region where current flows in a direction along the thickness of the separator 5 when the electrolytic cell 1 is in operation, and is the region facing the cathode reaction field in the electrolytic cell 1. The cathode reaction field is the three-dimensional region where the second catalyst layer 40 is arranged, that is, the three-dimensional region where the chemical reaction of the cathode part 4 occurs. To put it another way, the electrolytic region 59 is the region exposed from the window portion of the frame-shaped second insulating member 43 (Figures 2 and 3) in the electrolytic cell 1. In this example, the electrolytic region 59 has a recess 59c that is large enough to accommodate the second porous layer 42. In this example, the outer contour line of the electrolytic region 59 coincides with the outer contour line of the recess 59c. Unlike this example, the electrolytic region 59 may be a flat surface flush with the second surface 5b. 【0083】On the second surface 5b, a groove-shaped exhaust passage 56 is formed, connecting the electrolysis region 59 to the exhaust manifold 55. In this example, the exhaust passage 56 comprises a slit portion 56s and a flow straightening portion 56r. The slit portion 56s is a groove extending from the exhaust manifold 55 toward the electrolysis region 59. The flow straightening portion 56r is a groove along the exhaust edge of the electrolysis region 59. In this example, the exhaust edge is the upper edge of the recess 59c. The flow straightening portion 56r allows for the rapid recovery of hydrogen produced in the electrolysis region 59 from the entire length of the exhaust edge. 【0084】 The openings of the slit portion 56s and the rectifier portion 56r are covered by the second insulating member 43 (Figure 3). Multiple protrusions 56p are formed on the bottom surfaces of the slit portion 56s and the rectifier portion 56r. In this example, the shape of the protrusions 56p formed on the slit portion 56s is cylindrical. The protrusions 56p formed on the rectifier portion 56r are prismatic. These protrusions 56p make it difficult for the second insulating member 43 to fall into the exhaust passage 56. The formation of protrusions 56p in the exhaust passage 56 may partially reduce the flow path cross-sectional area of ​​the exhaust passage 56. However, since the fluid flowing through the exhaust passage 56 is mainly gas, even if the flow path cross-sectional area of ​​the exhaust passage 56 is somewhat reduced, the gas flow rate is not likely to decrease. Unlike this example, the exhaust passage 56 may have the same configuration as the discharge passage 54, that is, a configuration that includes a tunnel portion 54t. 【0085】 On the second surface 5b, a double seal groove 57 is formed around the supply manifold 51, surrounding the supply manifold 51. Similarly, a double seal groove 58 is formed around the discharge manifold 53, surrounding the discharge manifold 53. Both the seal grooves 57 and 58 are annular. In the electrolytic cell 1, annular seal material is fitted into these seal grooves 57 and 58. The annular seal material prevents leakage of conductive fluid from each manifold 51 and 53. The seal grooves 57 and 58 may be single. 【0086】As shown in Figure 6, the main body 5P of this example is composed of a first plate material 5A and a second plate material 5B that are bonded together. The first plate material 5A has a surface that constitutes the first surface 5a of the separator 5 and a first joining surface 5c opposite to the first surface 5a. The second plate material 5B has a surface that constitutes the second surface 5b of the separator 5 and a second joining surface 5d opposite to the second surface 5b. The first joining surface 5c and the second joining surface 5d are arranged to face each other. 【0087】 The first plate material 5A includes a bypass hole 52th that penetrates the first plate material 5A and a bypass groove 52tg formed in the first joining surface 5c. The first end of the bypass groove 52tg is connected to the supply manifold 51. The second end of the bypass groove 52tg is connected to the bypass hole 52th. In other words, the bypass groove 52tg extends along the first joining surface 5c in the direction from the supply manifold 51 toward the electrolytic region 50. When the first plate material 5A having such a configuration is joined with the second plate material 5B, a separator 5 having a tunnel section 52t is manufactured. The tunnel section 52t in this example is composed of a first tunnel section formed by the space enclosed by the bypass groove 52tg and the second joining surface 5d of the second plate material 5B, and a second tunnel section formed by the internal space of the bypass hole 52th. The first tunnel section and the second tunnel section are connected at a right angle. 【0088】 The bypass hole 52th can be easily formed using a general-purpose drill or the like. The inner surface of the bypass hole 52th may be finished with a reamer or the like. The bypass groove 52tg can also be easily formed using a general-purpose groove machining tool such as an end mill. In other words, a bent tunnel section 52t like the one in this example can be formed in the separator 5 without using special machining tools. When the first plate material 5A and the second plate material 5B are manufactured by mold forming, the bypass hole 52th and the bypass groove 52tg can also be formed by the mold. 【0089】The bypass groove 52tg may be formed only on the second joining surface 5d of the second plate material 5B. In that case, the space enclosed by the bypass groove 52tg formed on the second plate material 5B and the first joining surface 5c of the first plate material 5A forms the first tunnel portion. Alternatively, the bypass groove 52tg may be formed on both the first joining surface 5c of the first plate material 5A and the second joining surface 5d of the second plate material 5B. In that case, the space enclosed by the bypass groove 52tg formed on the first plate material 5A and the bypass groove 52tg formed on the second plate material 5B forms the first tunnel portion. 【0090】 An annular sealing member 5S is positioned between the first plate material 5A and the second plate material 5B. The annular sealing member 5S is positioned to surround the supply manifold 51 and the bypass groove 52tg. Figure 6 shows cross-sections of different parts of a single sealing member 5S. This sealing member 5S prevents conductive fluid from leaking through the gap between the first plate material 5A and the second plate material 5B. 【0091】 The configuration of the tunnel section 54t of the discharge passage 54 connected to the discharge manifold 53 shown in Figure 4 is the same as that of the tunnel section 52t of the supply passage 52. In the description of the tunnel section 52t, if you replace "supply manifold 51" with "discharge manifold 53", "tunnel section 52t" with "tunnel section 54t", "bypass hole 52th" with "bypass hole 54th", and "bypass groove 52tg" with "bypass groove 54tg", you will get the description of the tunnel section 54t. 【0092】 The tunnel sections 52t and 54t located inside the main body 5P are not exposed to the first surface 5a. These tunnel sections 52t and 54t are not blocked by the first insulating member 33 located on the first surface 5a of the separator 5. Therefore, the flow rates of conductive fluid and gas in the supply passage 52 and the discharge passage 54 are less likely to decrease. 【0093】Furthermore, in the electrolytic cell 1 of this example, a support member 5C is provided in the rectifier section 52r. Although not shown in the figure, a support member 5C is also provided in the rectifier section 54r. The support members 5C prevent the first insulating member 33 from falling into the rectifier sections 52r and 54r. As a result, the flow rate of the conductive fluid and gas in the rectifier sections 52r and 54r is less likely to decrease, and problems associated with a decrease in the flow rate of the conductive fluid and gas are less likely to occur. 【0094】 In this example, the support member 5C is made of a porous material and is arranged throughout the entire flow straightening section 52r. The support member 5C may also be arranged in a part of the flow straightening section 52r. The support member 5C is positioned by being fitted into the flow straightening section 52r. The support member 5C may also be fixed to the flow straightening section 52r by adhesive. The support member 5C, made of a porous material, also has the function of diffusing conductive fluid in the flow straightening section 52r. The minute flow channels formed inside the porous material may also be considered part of the tunnel section 52t. The material of the support member 5C may be metal or a resin material. The support member 5C has sufficient rigidity to prevent buckling during operation of the electrolytic cell 1. The thickness of the support member 5C is approximately the same as the depth of the flow straightening section 52r. 【0095】 Instead of the support member 5C, the rectifier sections 52r and 54r may have protrusions such as the convex portion 56p formed on the rectifier section 56r shown in Figure 5. The protrusions on the rectifier sections 52r and 54r are projections that extend from the bottom surface of the rectifier sections 52r and 54r. The protrusions prevent the first insulating member 33 from falling into the rectifier sections 52r and 54r. 【0096】 If the electrolytic cell 1 shown in Figure 1 is manufactured using the separator 5 described above, the flow rates of the conductive fluid and gas in the supply passage 52 and the discharge passage 54 are less likely to decrease. Therefore, in the electrolytic cell 1 of this example, a decrease in electrolysis efficiency due to a decrease in the flow rates of the conductive fluid and gas, and damage to the electrolytic cell due to an increase in the internal pressure of the electrolytic cell 1 are less likely to occur. 【0097】 [Embodiment 2] Referring to the schematic plan view in Figure 7, the separator 5 according to Embodiment 2 will be described. In Embodiment 2, only the differences from Embodiment 1 will be described. 【0098】The supply passage 52 in the separator 5 of this example comprises multiple tunnel sections 52t. The multiple tunnel sections 52t are independent of each other. Each tunnel section 52t opens at a different position in the rectifier section 52r. With this configuration, the conductive fluid from the supply manifold 51 is supplied in a dispersed manner to different positions in the rectifier section 52r. Therefore, the conductive fluid flows easily into the electrolytic region 50 in a dispersed state along the supply edge B1 of the electrolytic region 50. 【0099】 The discharge passage 54 in the separator 5 of this example comprises multiple tunnel sections 54t. The multiple tunnel sections 54t are independent of each other. Each tunnel section 54t opens at a different position in the rectifier section 54r. With this configuration, the conductive fluid from the electrolytic region 50 can be quickly recovered from the entire length of the discharge edge B2 of the electrolytic region 50. 【0100】 As shown in Figure 7, when multiple tunnel sections 52t and 54t are independently provided between the manifolds 51 and 53 and the electrolytic region 50, the maximum width of the tunnel sections 52t and 54t in a plan view is the maximum width of each tunnel section 52t and 54t. In Figure 7, the distance between adjacent tunnel sections 52t and 54t is relatively large, but adjacent tunnel sections 52t and 54t may have portions that are close together. In other words, multiple tunnel sections 52t and 54t may have portions that are close together and portions that are far apart. Adjacent tunnel sections 52t and 54t being close together means, for example, that in a plan view, the distance between adjacent tunnel sections 52t and 54t is smaller than the maximum width of the tunnel sections 52t and 54t. 【0101】 Unlike this example, the tunnel sections 52t and 54t may include a first tunnel section directly connected to the manifolds 51 and 53, and a plurality of second tunnel sections branching off from the first tunnel section. The ends of the second tunnel sections are connected to the flow straightening sections 52r and 54r. In this case, the maximum width of the first tunnel section is, for example, greater than or equal to the sum of the maximum widths of the plurality of second tunnel sections. 【0102】[Embodiment 3] The separator 5 of Embodiment 3 will be described with reference to the partial cross-sectional view of Figure 8 and the IX-IX cross-sectional view of Figure 9. Figure 8 is a partial cross-sectional view of the electrolytic cell 1 equipped with the separator 5 of Embodiment 3, cut at a position corresponding to the IV-IV cross-section in Figure 4. In Embodiment 3, only the differences from Embodiments 1 and 2 will be described. 【0103】 As shown in Figure 8, the main body 5P of the separator 5 in this example is made of a single plate. The main body 5P includes a surface groove 5g formed on the first surface 5a and an attachment member 6 fitted into the surface groove 5g. 【0104】 The surface groove 5g extends from the opening edge of the supply manifold 51 toward the electrolytic region 50. The surface groove 5g may be formed on the first surface 5a by machining or by transferring the shape of the inner circumferential surface of a mold. The surface groove 5g can be formed without using special tools or molds. 【0105】 The attachment member 6 in this example is gutter-shaped. As shown in Figure 9, the gutter-shaped attachment member 6 comprises a bottom portion 60 and two side wall portions 61, 61. The portion facing the bottom portion 60 is an opening 65. The attachment member 6 is fitted into the surface groove 5g such that the opening 65 faces the bottom surface of the surface groove 5g. As a result, the tunnel portion 52t of the supply passage 52 is formed by the space enclosed by the inner circumferential surface of the attachment member 6 and the bottom surface of the surface groove 5g. 【0106】 The width of the attachment member 6 along the direction in which the two side walls 61, 61 are aligned is approximately equal to the width of the surface groove 5g. Also, the height of the side walls 61 is approximately equal to the depth of the surface groove 5g. In this example, the outer surface of the bottom 60 of the attachment member 6 is flush with the first surface 5a of the main body 5P. 【0107】 The attachment member 6 may be made of metal or an insulating material. The attachment member 6 made of an insulating material has the function of making it difficult for shunt current to flow. The bottom surface of the surface groove 5g may also have an insulating layer made of an insulating material. 【0108】The attachment member 6 may be ring-shaped. For example, the attachment member 6 may be rectangular tubular in shape, following the inner circumferential shape of the surface groove 5g. In this case, the internal space of the attachment member 6 functions as a tunnel 52t. 【0109】 Although not shown in this example, the discharge passage 54 connecting the electrolysis area 50 and the discharge manifold 53 can also employ a configuration similar to that of the supply passage 52 in Figures 8 and 9. Furthermore, the number of tunnel sections 52t formed by the attachment member 6 may be multiple, similar to the configuration in Embodiment 2. 【0110】 [Embodiment 4] Referring to Figure 10, the separator 5 of Embodiment 4, which is a modified version of Embodiment 1, will be described. In Embodiment 4, only the differences from Embodiment 1 will be described. 【0111】 The separator 5 of Embodiment 4 includes an insulating layer 7 that covers the inner circumferential surface 511 of the supply manifold 51 and the inner circumferential surface of the tunnel portion 52t. The insulating layer 7 makes it difficult for shunt current to flow. Therefore, by including the insulating layer 7 in the separator 5, the electrolysis efficiency of the electrolytic cell 1 is less likely to decrease. 【0112】 The insulating layer 7 is formed, for example, by coating. The insulating layer 7 is formed, for example, by a polymer material. The polymer material is, for example, a resin material having at least one of alkali resistance and heat resistance in addition to electrical insulation. A resin material having alkali resistance is a resin material that has resistance to conductive fluids with a pH of 8 or higher. A resin material having heat resistance is a resin material that has resistance to temperatures of 80°C or lower. For example, the resin material described in the section on the first insulating member 33 can be used. 【0113】 [Embodiment 5] The main body 5P of Embodiments 1 to 4 may include a conductive plate and a frame portion surrounding the conductive plate. The frame portion may be made of, for example, the resin material described above. 【0114】1 Electrolytic cell 10 Cell module 2 Electrolyte membrane 21 First surface, 22 Second surface 3 Anode section 30 First catalyst layer, 31 First separator, 32 First porous layer, 33 First insulating member 4 Cathode section 40 Second catalyst layer, 41 Second separator, 42 Second porous layer, 43 Second insulating member 5 Separator A1, A2, A3, A4 Opening, B1 Supply edge, B2 Discharge edge 5α Central section, 5β Outer periphery section 5P Main body 5A First plate material, 5B Second plate material, 5C Support member, 5S Seal member 5a First surface, 5b Second surface, 5c First bonding surface, 5d Second bonding surface, 5g Surface groove 50, 59 Electrolytic region, 50c, 59c Recess 51 Supply manifold, 511 Inner circumferential surface 52 Flow path (supply path), 52r straightening section, 52t tunnel section, 52tg bypass groove, 52th bypass hole, 53 discharge manifold, 54 flow path (discharge path), 54r straightening section, 54t tunnel section, 54tg bypass groove, 54th bypass hole, 55 exhaust manifold, 56 exhaust path, 56p protrusion, 56r straightening section, 56s slit section, 57, 58 seal groove, 6 attachment member, 60 bottom section, 61 side wall section, 65 opening, 7 insulating layer, 8 flow mechanism, 81 anode supply pipe, 83 anode discharge pipe, 85 cathode discharge pipe, 9 DC power supply, 100 hydrogen production apparatus

Claims

1. A separator used in an electrolytic cell for producing hydrogen from water contained in a conductive fluid, comprising a plate-shaped body, the body comprising: an electrolytic region disposed in the center of a first surface of the body; a manifold formed on the outer periphery surrounding the central portion of the first surface and penetrating the body; and a flow path connecting the electrolytic region and the manifold, wherein the flow path comprises a tunnel portion inside the body that connects to the inner circumferential surface of the manifold.

2. The separator according to claim 1, wherein the main body comprises a first plate material having the first surface and a second plate material having a second joining surface bonded to a first joining surface on the opposite side of the first surface of the first plate material, and the tunnel portion comprises an internal space of a bypass hole penetrating the first plate material and an internal space of a bypass groove formed on at least one of the first joining surface and the second joining surface, which connects the manifold and the bypass hole.

3. The separator according to claim 1, wherein the main body comprises a surface groove extending from the opening edge of the manifold on the first surface toward the electrolytic region, and a trough-shaped or tubular attachment member fitted into the surface groove, and the tunnel portion is formed by the internal space of the attachment member.

4. The separator according to any one of claims 1 to 3, wherein, when the first surface is viewed from above, the maximum width of the opening of the tunnel portion is less than or equal to the length of the adjacent edge of the electrolytic region, and the adjacent edge is the edge of the outer peripheral edge of the electrolytic region that is close to the manifold.

5. The separator according to any one of claims 1 to 4, wherein the cross-sectional area of ​​the flow path in the tunnel section is less than or equal to the cross-sectional area of ​​the flow path in the manifold.

6. The separator according to any one of claims 1 to 5, wherein the end of the tunnel portion opens to the inner circumferential surface of the manifold.

7. The separator according to any one of claims 1 to 6, wherein the flow path comprises a rectifier portion connected to the adjacent edge of the electrolytic region, and the adjacent edge is the edge of the outer periphery of the electrolytic region that is close to the manifold.

8. The separator according to any one of claims 1 to 7, wherein the main body is a metal plate or a plate made of a composite material including a conductive material and a resin.

9. The separator according to claim 8, further comprising an insulating layer covering the inner circumferential surface of the manifold and the inner circumferential surface of the tunnel portion.

10. An electrolytic cell comprising: an anode section through which a conductive fluid flows; a cathode section through which hydrogen is produced from water contained in the conductive fluid; and an electrolyte membrane separating the anode section and the cathode section, wherein the anode section comprises: a separator according to any one of claims 1 to 9; and a frame-shaped insulating member disposed on the first surface of the separator.

11. The electrolytic cell according to claim 10, wherein the material of the insulating member is a polymer material.

12. The electrolytic cell according to claim 10 or claim 11, wherein the conductive fluid is an alkaline aqueous solution and the electrolyte membrane is an anion exchange membrane.

13. The electrolytic cell according to claim 12, wherein when the entire alkaline aqueous solution is considered to be 100% by mass, the concentration of the electrolyte contained in the alkaline aqueous solution is 0.1% by mass or more.

14. The electrolytic cell according to any one of claims 10 to 13, wherein the temperature of the conductive fluid in the anode portion is 45°C or higher and 80°C or lower.

15. A hydrogen production apparatus comprising a cell module in which a plurality of electrolytic cells are connected in series, wherein each of the plurality of electrolytic cells is an electrolytic cell according to any one of claims 10 to 14.

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