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 this separator comprises a conductive plate and an insulating layer that covers a part of the conductive plate. The conductive plate is provided with: an electrolysis region which is formed in a central part of a first surface of the conductive plate; and a supply manifold which is formed in an outer peripheral part that surrounds the central part on the first surface, and which penetrates the conductive plate. The insulating layer is provided with: a first covering part which covers the inner peripheral surface of the supply manifold; and a second covering part which forms a groove-shaped supply path that connects from the supply manifold to the electrolysis region. The electrolysis region is exposed from the insulating layer.

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 path connected to the supply manifold, a second connecting path connected to the discharge manifold, and an electrode passage flow path connected to the first and second connecting paths. The electrode passage flow path is the region in the separator where the power supply element 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 path, and the electrode passage flow path. The alkaline aqueous solution that has passed through the anode and cathode is discharged from the discharge manifold through the second connecting path. 【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 conductive plate and an insulating layer covering a portion of the conductive plate. The conductive plate comprises an electrolytic region formed in the center of a first surface of the conductive plate and a supply manifold formed on the outer periphery surrounding the central portion of the first surface and penetrating the conductive plate. The insulating layer comprises a first covering portion covering the inner circumferential surface of the supply manifold and a second covering portion forming a groove-shaped supply passage connecting the supply manifold to the electrolytic region. The electrolytic region is exposed from the insulating layer. 【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 cross-sectional view taken along line VI-VI in Figure 4. Figure 7 is a cross-sectional view taken along line VII-VII in Figure 4. Figure 8 is a cross-sectional view taken along line VIII-VIII in Figure 4. Figure 9 is a cross-sectional view taken along line IX-IX in Figure 4. Figure 10 is a schematic plan view of the first surface of the separator according to Embodiment 2. Figure 11 is a schematic plan view of the first surface of the separator according to Embodiment 3. Figure 12 is a partial cross-sectional view of the separator according to Embodiment 4. Figure 13 is a partially enlarged perspective view of the separator according to Embodiment 5. 【0008】 [Problems this disclosure aims to solve] When conductive fluid is supplied in parallel to each electrolytic cell from a common source, 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, the Faraday efficiency decreases. The Faraday efficiency is the ratio of the amount of charge that contributed to hydrogen production, when the total amount of charge supplied to the electrolytic cell is taken as 100%. The larger the shunt current, the lower the Faraday efficiency. 【0009】 One of the objectives of this disclosure is to provide a separator that can reduce shunt current in an electrolytic cell. 【0010】[Description of Embodiments of the Disclosure] First, embodiments of the Disclosure will be listed and described. 【0011】 <1> A separator according to one aspect 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 conductive plate and an insulating layer covering a part of the conductive plate. The conductive plate comprises an electrolytic region formed in the center of a first surface of the conductive plate and a supply manifold formed on the outer periphery surrounding the central part of the first surface and penetrating the conductive plate. The insulating layer comprises a first covering portion covering the inner circumferential surface of the supply manifold and a second covering portion forming a groove-shaped supply passage connecting the supply manifold to the electrolytic region. The electrolytic region is exposed from the insulating layer. 【0012】 In the electrolytic cell using the separator described above, a conductive porous layer is arranged in the electrolytic region of the conductive plate. That is, the electrolytic region of the conductive plate 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. Recesses may or may not be formed in this electrolytic region. The recesses may be, for example, depressions large enough to fit the porous layer, or they may be multiple grooves configured for the flow of a conductive fluid. An electrolytic region in which no recesses are formed is simply a flat surface flush with the first surface. 【0013】 In the above separator, the supply manifold and supply path are covered with an insulating layer. Because the conductive fluid flows through this insulated supply manifold and supply path, shunt current is less likely to flow, thus preventing a decrease in the Faraday efficiency of the electrolytic cell. Furthermore, the Joule heat generated by the shunt current is reduced, minimizing thermal degradation of the electrolytic cell components, including the separator. 【0014】 <2> In the separator described in <1> above, the conductive plate is provided with a groove that extends from the edge of the supply manifold toward the electrolytic region, and the inner circumferential surface of the groove may be covered by the second covering portion. 【0015】According to the configuration described in <2> above, at the position where the supply path is formed, a portion of the insulating layer is positioned to fit into the groove of the conductive plate, making it difficult for the supply path to shift relative to the conductive plate. 【0016】 <3> In the separator described in <1> above, the portion of the conductive plate in which the supply path is formed may be a flat surface. 【0017】 The configuration described in <3> above, as shown in Embodiment 4 with reference to Figure 12, for example, is one in which the supply path is formed only by an insulating layer on the flat surface of the first surface. With this configuration, it is not necessary to form grooves for the supply path on the first surface of the conductive plate. Therefore, the effort required for processing to form the grooves is reduced. 【0018】 <4> In the separator described in any of <1> to <3> above, the insulating layer may include a third covering portion extending from the first covering portion to the second surface of the conductive plate. The second surface is the surface opposite to the first surface. 【0019】 The second coating is located on the first surface. The third coating is located on the second surface. The first coating is positioned to connect the first and second surfaces. In other words, because the insulating layer spans both the first and second surfaces, the insulating layer is less likely to detach from the conductive plate. 【0020】 <5> In the separator described in any of <1> to <4> above, the minimum thickness of the insulating layer may be 1 μm or more. 【0021】 The minimum thickness of the insulating layer is the thickness of the thinnest point within the entire insulating layer. If the minimum thickness of the insulating layer is 1 μm or more, pinholes are less likely to occur in the insulating layer, and the insulating layer is more likely to exhibit sufficient insulating performance. 【0022】 <6> In the separator described in any of <1> to <5> above, the second covering portion may extend to the area around the supply manifold and the area around the supply passage on the first surface. 【0023】 The second covering extends around the supply manifold and the supply path, allowing for a more reliable reduction of shunt current. 【0024】 <7> In the separator described in <6> above, the second coating portion may be formed on the entire surface of the first surface excluding the electrolytic region. 【0025】 By forming a second insulating layer over the entire surface of the first surface excluding the electrolytic region, the shunt current can be reduced more reliably. Furthermore, when forming the insulating layer by vapor deposition or coating, the area that needs to be masked is limited to the electrolytic region, thus reducing the effort required to form the insulating layer. 【0026】 <8> In the separator described in any of <1> to <7> above, the supply path may include a slit portion extending from the supply manifold toward the electrolytic region and a rectifier portion connected to the end of the slit portion and along the supply edge in the electrolytic region. 【0027】 In the configuration described in <8> above, the second covering portion forms a slit portion and a flow straightening portion. The slit portion smoothly guides the conductive fluid from the supply manifold to the flow straightening portion. The number of slit portions may be one or more. The supply edge is a predetermined length of edge portion of the outer periphery of the electrolytic region that includes the portion closest to the supply manifold. For example, if the electrolytic region is rectangular, the side closest to the supply manifold is the supply edge. The flow straightening portion extending along the supply edge causes the conductive fluid to flow into the electrolytic region in a dispersed state along the supply edge of the electrolytic region. Therefore, chemical reactions in the electrolytic region are easily promoted. 【0028】 <9> In the separator described in any of <1> to <8> above, the conductive plate may be a metal plate or a plate made of a composite material containing 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. Conductive plates made from composite materials offer excellent productivity because manifolds and other components can be formed by mold molding. 【0030】 <10> In the separator described in any of <1> to <9> above, the material of the insulating layer may be a polymer material. 【0031】The insulating layer formed from polymer material is easily deformable to follow the deformation of the conductive plate and is less likely to detach from the conductive plate. 【0032】 <11> In the separator described in any of <1> to <10> above, the conductive plate is formed at a position different from the supply manifold on the outer periphery and includes a discharge manifold that penetrates the conductive plate, and the insulating layer may include a fourth covering portion that covers the inner circumferential surface of the discharge manifold and a fifth covering portion that forms a groove-shaped discharge passage connecting the electrolytic region to the discharge manifold. 【0033】 In the configuration described in <11> above, the discharge passage and discharge manifold are covered with an insulating layer. As the conductive fluid passes through this insulated discharge passage and discharge manifold, shunt current is less likely to flow, thus preventing a decrease in the Faraday efficiency of the electrolytic cell. 【0034】 Here, the formation state of the discharge channel, the fourth covering section, and the fifth covering section may be the same as the formation state of the supply channel, the first covering section, and the second covering section, respectively. In other words, in the provisions of <2> to <12> above, "supply channel" can be read as "discharge channel", "supply manifold" as "discharge manifold", "first covering section" as "fourth covering section", and "second covering section" as "fifth covering section". 【0035】 <12> In the separator described in any of <1> to <11> above, the second covering portion may be provided with a protrusion that protrudes from the bottom of the supply passage. 【0036】 In electrolytic cells, insulating materials are positioned to face the supply path. These insulating materials are, for example, flexible, frame-shaped gaskets. If a protrusion is formed at the bottom of the supply path, it can prevent the insulating material from falling into the path. If the insulating material falls into the supply path, the flow rate of conductive fluid in the path decreases, potentially reducing the Faraday efficiency of the electrolytic cell. 【0037】 <13> In the separator described in any of <1> to <12> above, the insulating layer may be a vapor-deposited layer or a coated layer. 【0038】The insulating layer formed by vapor deposition or coating is difficult to separate from the conductive plate. Also, the insulating layer can be made thin, and it is easy to obtain a separator with a thin thickness and low weight. 【0039】 <14> The separator according to any one of <1> to <12> above may include an adhesive layer that adheres the conductive plate and the insulating layer. 【0040】 The configuration of <14> above is obtained by adhering an insulating layer prepared independently of the conductive plate to the conductive plate. In this configuration, since it is necessary to handle the insulating layer separately from the conductive plate, the insulating layer tends to become thick in order to improve the handling property of the insulating layer. According to this configuration, since a thick insulating layer can be firmly fixed to the conductive plate, the insulation between the conductive plate and the conductive fluid tends to be high. Also, defects such as pinholes are less likely to occur in a thick insulating layer. 【0041】 <15> An electrolytic cell according to one aspect of the present disclosure includes an anode portion through which a conductive fluid flows, a cathode portion where hydrogen is produced from water contained in the conductive fluid, and an electrolyte membrane that separates the anode portion and the cathode portion, and the anode portion includes the separator according to any one of <1> to <14> above. 【0042】 In the above electrolytic cell, since the flow path of the conductive fluid excluding the electrolysis region in the separator is insulated by the insulating layer, the shunt current is reduced. Therefore, the above electrolytic cell is excellent in Faraday efficiency. 【0043】 <16> In the electrolytic cell according to <15> above, the conductive fluid may be an aqueous alkali solution, and the electrolyte membrane may be an anion exchange membrane. 【0044】 In an electrolytic cell using an anion exchange membrane, hydrogen can be produced without actively supplying a conductive fluid to the cathode. Therefore, the configuration of the cathode can be simplified. 【0045】 <17> A hydrogen production apparatus according to one aspect 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 <15> or <16> above. 【0046】The above-mentioned hydrogen production apparatus is equipped with an electrolytic cell that exhibits excellent Faraday efficiency, enabling efficient hydrogen production. 【0047】 [Details of Embodiments of the Disclosure] Hereinafter, specific examples of separators, electrolytic cells, and hydrogen production apparatus of the Disclosure will be described with reference to the drawings. The same reference numerals in the drawings indicate the same parts. The shapes, sizes, and positional relationships shown in each drawing are for illustrative purposes only and do not necessarily represent the actual shapes, sizes, and positional relationships. The present invention is not limited to the configurations shown in the embodiments, but is intended to include all modifications within the meaning and scope of the claims as indicated by the claims. 【0048】 [Embodiment 1] In Embodiment 1, the outline of a hydrogen production apparatus equipped with an electrolytic cell will be described first. Next, the basic configuration of the electrolytic cell and a cell module in which multiple electrolytic cells are connected in series will be described. Based on that description, the separator provided in the electrolytic cell will be described. 【0049】 <Hydrogen Production Apparatus> The hydrogen production apparatus 100 shown in Figure 1 comprises an electrolytic cell 1, a flow mechanism 8, and a DC power supply 9. The electrolytic cell 1 comprises an electrolyte membrane 2, an anode section 3, and a cathode section 4. In this example, the electrolyte membrane 2 is an anion exchange membrane (AEM). The AEM exchanges hydroxide ions (OH) from the cathode section 4 to the anode section 3. － ) 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. 【0050】The distribution mechanism 8 of this example includes an anode supply pipe 81 that supplies a conductive fluid to the anode portion 3, an anode discharge pipe 83 that discharges the conductive fluid from the anode portion 3, and a cathode discharge pipe 85 that discharges hydrogen from the cathode portion 4. Different from this example, a cathode supply pipe that supplies a conductive fluid to the cathode portion 4 may also be provided. The DC power supply 9 applies a DC voltage between the anode portion 3 and the cathode portion 4. The high potential electrode of the DC power supply 9 is connected to the anode portion 3, and the low potential electrode of the DC power supply 9 is connected to the cathode portion 4. 【0051】 The conductive fluid of this example is an alkaline aqueous solution. The alkaline aqueous solution is, for example, an aqueous solution of potassium hydroxide or sodium hydrogen carbonate. The alkaline aqueous solution promotes the electrolysis of water as compared with the case where the fluid supplied to the electrolytic cell 1 is pure water. 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 entire alkaline aqueous solution is 100% by mass. The concentration of the electrolyte may 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 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 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. 【0052】 The conductive fluid of the alkaline aqueous solution is supplied from the anode supply pipe 81 to the anode portion 3. In this example, the conductive fluid is not supplied to the cathode portion 4. H ２ O moves from the anode portion 3 through the electrolyte membrane 2 to the cathode portion 4. When a voltage is applied between the anode portion 3 and the cathode portion 4 by the DC power supply 9, the following chemical reactions occur in the first catalyst layer 30 of the anode portion 3 and the second catalyst layer 40 of the cathode portion 4. Anode portion 3: 4OH － →2H ２ O + O ２ + 4e － Cathode portion 4: 4H ２ O + 4e － →2H ２ + 4OH－ 【0053】 As shown in the chemical formula above, at the anode 3, water (H) is released from hydroxide ions. ２ O) and oxygen (O) ２ ) is produced and electrons are released. In the cathode section 4, water and electrons combine to form hydrogen (H ２ Hydrogen and hydroxide ions are produced. The hydroxide ions produced in the cathode section 4 move to the anode section 3 through the electrolyte membrane 2, which is an AEM. The oxygen produced in the anode section 3 is discharged to the outside of the electrolytic cell 1 from the anode discharge pipe 83 along with the alkaline aqueous solution. The hydrogen produced in the cathode section 4 is discharged to the outside of the electrolytic cell 1 from the cathode discharge pipe 85. 【0054】 <Electrolytic Cell> A more detailed explanation of the electrolytic cell 1 will be given based on Figure 2. As shown in the exploded perspective view of Figure 2, the anode portion 3 of the electrolytic cell 1 comprises a first catalyst layer 30, a first separator 31, a first porous layer 32, and a first insulating member 33. 【0055】 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 portion 3. Known catalysts such as noble metals, metal oxides, or those supported on carbon or the like can be used as catalysts in the first catalyst layer 30. 【0056】 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. 【0057】 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. 【0058】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. The first insulating member 33 also functions as a gasket. The first insulating member 33 is formed of, for example, a resin material. 【0059】 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. 【0060】 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. 【0061】 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. 【0062】 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, and the function of mechanically protecting the electrolyte membrane 2. The second insulating member 43 also functions as a gasket. The second insulating member 43 is formed of, for example, a resin material. 【0063】 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). 【0064】 <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. 【0065】 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. 【0066】 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. 【0067】 <Separator> The separator 5 in this example comprises a conductive plate 5P and an insulating layer 6 covering a part of the conductive plate 5P, as shown in Figures 4 and 5. The conductive plate 5P is a single molded product divided into a central part 5α including the area center of the conductive plate 5P and an outer peripheral part 5β surrounding the central part 5α. As will be described later, the central part 5α forms an electrolytic region 50. In other words, the electrolytic region 50 is formed by a part of the conductive plate 5P. In Figures 4 and 5, the area in which the insulating layer 6 is formed is shown by cross-hatching. 【0068】The conductive plate 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. The metal plate has 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 conductive plate 5P may also comprise 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. 【0069】 The conductive plate 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 conductive plate 5P made of the composite material has excellent productivity because it can be easily formed with irregularities by mold molding. 【0070】 The insulating layer 6 is formed of, for example, a polymer material. The insulating layer 6 formed of the polymer material is easily deformable in accordance with the deformation of the conductive plate 5P and is not easily detached from the conductive plate 5P. 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 that has resistance to conductive fluids with a pH of 8 or higher. A resin material having heat resistance is a resin that has resistance to temperatures of 80°C or higher. 【0071】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. 【0072】 The separator 5 includes a supply manifold 51, a discharge manifold 53, and an exhaust manifold 55 that penetrate the conductive plate 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. 【0073】An electrolytic region 50 is formed in the central part 5α of the first surface 5a of the conductive plate 5P. As shown in Figure 3, the electrolytic region 50 is the region where the first porous layer 32 is arranged. That is, the electrolytic region 50 on the conductive plate 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. The outer contour line of the electrolytic region 50 in this example coincides with the outer contour line of the recess 50c. Unlike this example, the electrolytic region 50 may be a flat surface. 【0074】 On the first surface 5a, a groove-shaped supply passage 52 is formed, connecting the supply manifold 51 to the electrolytic region 50. In this example, the supply passage 52 includes a slit portion 52s and a rectifier portion 52r. When the first insulating member 33 is placed on top of the separator 5, the first insulating member 33 overlaps the supply passage 52. That is, the supply passage 52 is not exposed to the window portion of the first insulating member 33. 【0075】 The slit portion 52s is a groove extending from the supply manifold 51 toward the electrolytic region 50. In this example, the slit portion 52s is generally J-shaped, but is not limited to such a shape. For example, the slit portion 52s may be meandering in shape. 【0076】The rectifier section 52r is connected to the end of the slit section 52s and is a groove along the supply edge 501 in the electrolysis region 50. The supply edge 501 is the 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 501 is the lower edge of the square-shaped recess 50c. The rectifier section 52r in this example is roughly triangular in shape with the supply edge 501 as its base. Due to this rectifier section 52r, the conductive fluid flows into the electrolysis region 50 in a dispersed state along the supply edge of the electrolysis region 50. Therefore, the chemical reaction in the electrolysis region 50 is easily promoted. The rectifier section 52r is not an essential component. 【0077】 The first surface 5a further has a groove-shaped discharge passage 54 that connects the electrolytic region 50 to the discharge manifold 53. In this example, the discharge passage 54 includes a slit portion 54s and a rectifier portion 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. 【0078】 The slit portion 54s is a groove extending from the discharge manifold 53 toward the electrolysis region 50. In this example, the slit portion 54s is generally J-shaped, but is not limited to such a shape. For example, the slit portion 54s may be meandering in shape. 【0079】 The rectifier section 54r is connected to the end of the slit section 54s and is a groove along the discharge edge 502 in the electrolysis region 50. The discharge edge 502 is the 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 502 is the upper edge of the square-shaped recess 50c. In this example, the rectifier section 54r is roughly triangular in shape with the discharge edge as its base. 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 502, resulting in smoother flow of the conductive fluid 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. 【0080】An electrolytic region 59 is formed in the central part 5α of the second surface 5b of the conductive plate 5P shown in Figure 5. 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 on the conductive plate 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. The outer contour line of the electrolytic region 59 in this example coincides with the outer contour line of the recess 59c. Unlike this example, the electrolytic region 59 may be a flat surface. 【0081】 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 includes 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 592 of the electrolysis region 59. In this example, the exhaust edge 592 is the upper edge of the recess 59c. The flow straightening portion 56r allows for the rapid recovery of hydrogen from the electrolysis region 59 along the entire length of the exhaust edge 592. 【0082】 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 the manifold. The seal grooves 57 and 58 may be single. 【0083】In this example, the insulating layer 6 is formed around the supply manifold 51 and the exhaust manifold 53, as shown in Figures 4 and 5. The two insulating layers 6 are independent of each other. The insulating layer 6 insulates the portion of the electrolytic cell 1 that is filled with conductive fluid during operation. In this example, since the fluid flowing through the exhaust passage 56 and exhaust manifold 55 is hydrogen gas, which has a lower electrical conductivity than conductive fluid, the insulating layer 6 does not need to be placed around the exhaust passage 56 and exhaust manifold 55. 【0084】 The insulating layer 6 formed around the supply manifold 51 comprises a first covering portion 61, a second covering portion 62, and a third covering portion 63, as shown in Figure 6. The first covering portion 61 covers the inner circumferential surface 511 of the supply manifold 51. In this configuration, a flow path for the conductive fluid is formed by the space enclosed by the first covering portion 61 at the location of the supply manifold 51. The first covering portion 61 insulates the conductive plate 5P from the conductive fluid at the location of the supply manifold 51. As a result, the shunt current at the location of the supply manifold 51 is reduced. 【0085】 The second covering portion 62 forms the supply passage 52, as shown in Figures 4 and 7. In this example, the second covering portion 62 covers the inner circumferential surface of the groove 5g formed on the first surface 5a of the conductive plate 5P, as shown in Figure 7. The groove 5g has a contour line that follows the contour line of the supply passage 52 in Figure 4 when the first surface 5a is viewed from above. Therefore, the supply passage 52 is formed by the space enclosed by the inner circumferential surface of the groove 5g. The width and depth of the supply passage 52 may vary depending on the size of the electrolytic cell 1. The second covering portion 62 insulates the conductive plate 5P from the conductive fluid at the location of the supply passage 52. As a result, the shunt current at the location of the supply passage 52 is reduced. 【0086】As shown in Figure 4, the second covering portion 62 in this example extends around the supply manifold 51 and the supply passage 52 on the first surface 5a. When the first surface 5a is viewed from above, the second covering portion 62 covers an area of ​​a predetermined width from the opening edge of the supply manifold 51 and the contour line of the supply passage 52. As a result, the shunt current at the location of the supply manifold 51 and the location of the supply passage 52 is reduced more reliably. The predetermined width is, for example, 1 mm (millimeters) or more. In the example shown in Figure 4, the second covering portion 62 covers an area of ​​a width greater than or equal to the predetermined width. The outer peripheral contour shape of the second covering portion 62 in this example when the first surface 5a is viewed from above may be a simple shape such as a rectangle. When forming a second covering portion 62 with a simple outer peripheral contour shape, masking for forming the second covering portion 62 is easy. 【0087】 As shown in Figures 4 and 7, the second covering portion 62 in this example is provided with a protrusion 67 that extends from the bottom of the slit portion 52s of the supply passage 52. This protrusion 67 prevents the first insulating member 33 (Figures 2 and 3) from falling into the supply passage 52. Therefore, the amount of conductive fluid flowing through the supply passage 52 is not easily reduced by the first insulating member 33, and the Faraday efficiency of the electrolytic cell 1 is not easily reduced. In Figure 7, the protrusion height of the protrusion 67 reaches the surface position of the second covering portion 62, making it easy to obtain the above-mentioned effect of preventing falling in. The protrusion height of the protrusion 67 may be lower than the surface position of the second covering portion 62. The number and arrangement of these protrusions 67 can be selected as appropriate. 【0088】 As shown in Figure 4, the protrusion 67 is also formed at the position of the rectifier 52r. The protrusion 67 at this position also has the function of diffusing the conductive fluid in a direction along the supply edge of the recess 50c. 【0089】 As shown in Figure 6, the third covering portion 63 is connected to the first covering portion 61 and extends from the first covering portion 61 to the second surface 5b of the conductive plate 5P. In this example, the third covering portion 63 extends to the periphery of the seal groove 57, as shown in Figure 5. As shown in Figure 6, the third covering portion 63 covers the inner circumferential surface of the seal groove 57, reducing the shunt current at this location. 【0090】As shown in Figure 6, the second coating portion 62 is positioned on the first surface 5a, and the third coating portion 63 is positioned on the second surface 5b. The first coating portion 61 is positioned to connect the second coating portion 62 and the third coating portion 63. In other words, since the insulating layer 6 in this example spans both the first surface 5a and the second surface 5b, the insulating layer 6 is less likely to detach from the conductive plate 5P. 【0091】 The insulating layer 6 formed around the discharge manifold 53 shown in Figures 4 and 5 comprises a fourth covering portion 64, a fifth covering portion 65, and a sixth covering portion 66, as shown in Figures 8 and 9. The fourth covering portion 64, the fifth covering portion 65, and the sixth covering portion 66 each have the same configuration as the first covering portion 61, the second covering portion 62, and the third covering portion 63, respectively. In the description of the first covering portion 61, if the reference diagrams are Figures 8 and 9, and "first covering portion 61" is read as "fourth covering portion 64", "supply manifold 51" is read as "discharge manifold 53", and "supply passage 52" is read as "discharge passage 54", then the description becomes the fourth covering portion 64. Similarly, in the description of the second covering portion 62, if "second covering portion 62" is read as "fifth covering portion 65", then the description becomes the fifth covering portion 65. In the description of the third covering portion 63, if you replace "third covering portion 63" with "sixth covering portion 66," it becomes a description of the sixth covering portion 66. 【0092】The minimum thickness of the insulating layer 6 is, for example, 1 μm or more. The minimum thickness is the thickness of the thinnest part of the entire insulating layer 6. If the minimum thickness of the insulating layer 6 is 1 μm or more, pinholes are less likely to occur in the insulating layer 6, and the insulating layer 6 is more likely to exhibit sufficient insulating performance. The minimum thickness of the insulating layer 6 may be 3 μm or more, 5 μm or more, or 10 μm or more. The larger the minimum thickness, the higher the insulating performance of the insulating layer 6, but the upper limit of the minimum thickness is, for example, 1000 μm. The minimum thickness may be 1 μm or more and 1000 μm or less, 3 μm or more and 800 μm or less, 5 μm or more and 600 μm or less, or 10 μm or more and 600 μm or less. On the other hand, the maximum thickness of the insulating layer 6, which is the thickness of the thickest part of the entire insulating layer 6, may be, for example, 1000 times or less the minimum thickness, 800 times or less, or 600 times or less. The absolute value of the maximum thickness can be, for example, 5 mm or less, 4 mm or less, or 3 mm or less. Furthermore, if the maximum thickness is less than 3 mm, it is easier to construct a thin electrolytic cell 1. 【0093】 The insulating layer 6 is a vapor-deposited layer or a painted layer. When forming the insulating layer 6 by vapor deposition or painting, the conductive plate 5P may be masked before vapor deposition or painting. The insulating layer 6 formed by vapor deposition or painting adheres closely to the conductive plate 5P and is difficult to detach from it. Furthermore, vapor deposition or painting allows the insulating layer 6 to be made thinner, making it easier to obtain a thin and lightweight separator 5. Unlike this example, the insulating layer 6 may be prepared independently of the conductive plate 5P. 【0094】 If the electrolytic cell 1 shown in Figure 1 is manufactured using the separator 5 described above, the flow path of the conductive fluid excluding the electrolytic region 50 in the separator 5 is insulated by the insulating layer 6, thereby reducing the shunt current. Therefore, the electrolytic cell 1 in this example has excellent Faraday efficiency. If a hydrogen production apparatus 100 is manufactured using this electrolytic cell 1 with excellent Faraday efficiency, hydrogen can be produced efficiently. 【0095】 [Embodiment 2] Referring to the schematic plan view in Figure 10, the separator 5 according to Embodiment 2 will be described. In Embodiment 2, only the differences from Embodiment 1 will be described. 【0096】In the separator 5 of Figure 10, the second coating portion 62 of the insulating layer 6 is formed over the entire surface of the first surface 5a of the conductive plate 5P, excluding the electrolytic region 50. In other words, the second coating portion 62 in this example includes the second coating portion 62 and the fifth coating portion 65 of Embodiment 1. Furthermore, this second coating portion 62 also covers the area around the exhaust manifold 55. With this configuration, the shunt current can be reduced compared to the configuration of Embodiment 1. 【0097】 In this example configuration, when forming the insulating layer 6 by vapor deposition or coating, masking is only required in the electrolytic region 50. Therefore, the separator 5 can be manufactured with high productivity. 【0098】 [Embodiment 3] Referring to the schematic plan view in Figure 11, the separator 5 according to Embodiment 3 will be described. In Embodiment 3, only the differences from Embodiments 1 and 2 will be described. 【0099】 In the separator 5 shown in Figure 11, a plurality of groove-shaped recesses 50c are formed in the electrolytic region 50. In this example, the recesses 50c extend in a longitudinal direction perpendicular to the direction along the length of the rectifier section 52r of the supply passage 52. The plurality of recesses 50c are arranged parallel to each other. A ridge 50r is formed between two adjacent recesses 50c. In this example, the ridge 50r is flush with the first surface 5a. The lower end of the recess 50c is connected to the rectifier section 52r of the supply passage 52. The upper end of the recess 50c is connected to the rectifier section 54r of the discharge passage 54. The groove-shaped recesses 50c are not limited to straight grooves; for example, they may be meandering grooves. 【0100】 In this example, the first porous layer 32 (Figures 2 and 3) is placed on the ridge portion 50r. The first porous layer 32, composed of a porous metal, has high rigidity. The cell module 10, in which multiple electrolytic cells 1 are stacked, is used in a tightened state. Even in this state, the first porous layer 32 maintains pores through which conductive fluid can flow. Therefore, the conductive fluid that flows into the recess 50c of the separator 5 can flow towards the first catalyst layer 30 of the anode portion 3 using the pores of the first porous layer 32 as a flow path. In this configuration, the flow of conductive fluid in the electrolytic region 50 is smooth, so the internal pressure of the electrolytic cell 1 does not become too high. 【0101】[Embodiment 4] Referring to the cross-sectional view in Figure 12, the separator 5 according to Embodiment 4 will be described. In Embodiment 4, only the differences from Embodiments 1 to 3 will be described. 【0102】 Figure 12 is a schematic cross-sectional view of the separator 5 of Embodiment 4, cut at a position corresponding to the VII-VII section in Figure 4. In the separator 5 of Figure 12, the portion of the conductive plate 5P where the supply passage 52 is formed is a flat surface without irregularities. In other words, the conductive plate 5P does not have a groove for the supply passage 52, and the supply passage 52 is formed by a groove-shaped recess in a part of the second covering portion 62 of the insulating layer 6. 【0103】 In this example configuration, the thickness of the second covering portion 62 at the bottom of the supply path 52 is the minimum thickness of the insulating layer 6. The minimum thickness of the second covering portion 62 is, for example, 1 μm or more. If the minimum thickness of the second covering portion 62 is 1 μm or more, sufficient insulation can be provided between the conductive plate 5P and the conductive fluid at the location of the supply path 52. The minimum thickness of the second covering portion 62 may be 3 μm or more, 5 μm or more, or 10 μm or more. 【0104】 It can be difficult to accurately form the second coating portion 62, which is partially recessed in a groove-like shape, by vapor deposition or coating. Therefore, in this example, the insulating layer 6 is integrated with the conductive plate 5P by bonding an insulating layer 6, which is prepared independently of the conductive plate 5P, to the conductive plate 5P. Specifically, an adhesive layer 6B is formed between the conductive plate 5P and the insulating layer 6. The adhesive layer 6B is formed, for example, with an insulating adhesive. In this configuration, since the insulating layer 6 needs to be handled independently of the conductive plate 5P, the insulating layer 6 tends to be thicker in order to improve the handling of the insulating layer 6. A thick insulating layer is less prone to defects such as pinholes. In the separator 5 of Embodiment 4, since the thick insulating layer 6 can be firmly fixed to the conductive plate 5P by the adhesive layer 6B, the insulation between the conductive plate 5P and the conductive fluid tends to be high. Also, if the location on the conductive plate 5P where the second coating portion 62 is placed is a flat surface, it is easier to form the adhesive layer 6B. The insulating layer 6 is formed, for example, by a molded resin. If the adhesive layer 6B has insulating properties, the minimum thickness includes the thickness of the adhesive layer 6B. 【0105】Although not shown in the figures, in Embodiment 4, the discharge passage 54 has the same configuration as the supply passage 52 shown in Figure 12. 【0106】 [Embodiment 5] The separator 5 according to Embodiment 5 will be described with reference to the partial perspective view shown in Figure 13. In Embodiment 5, only the differences from Embodiments 1 to 4 will be described. 【0107】 As shown in Figure 13, the electrolytic region 50 in this example protrudes from the first surface 5a. Multiple groove-shaped recesses 50c are formed in the protruding portion. In this configuration, the first porous layer 32 is placed on the ridges 50r formed between two adjacent recesses 50c. 【0108】 The configuration of the supply passage 52 in the separator 5 in this example is suitable for the configuration of Embodiment 4. As shown in Figure 12, the bottom of the supply passage 52 in Embodiment 4 is higher than the first surface 5a. Therefore, the conductive fluid from the supply passage 52 flows easily into the recess 50c in Figure 13. 【0109】 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 5α Central section, 5β Outer periphery section 5P Conductive plate 5a First surface, 5b Second surface, 5g Groove section 50, 59 Electrolytic region, 50c, 59c Recessed section, 50r Ridge section 501 Supply edge, 502 Discharge edge, 592 Exhaust edge 51 Supply manifold, 511 Inner surface 52 Supply passage, 52r Rectifying section, 52s Slit section 53 Discharge manifold 54 Discharge passage, 54r 54s slit section 55 exhaust manifold 56 exhaust passage 56r rectifier section 56s slit section 57, 58 seal groove 6 insulating layer 6B adhesive layer 61 first coating section 62 second coating section 63 third coating section 64 fourth coating section 65 fifth coating section 66 sixth coating section 67 protrusion 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 conductive plate; and an insulating layer covering a part of the conductive plate, wherein the conductive plate comprises: an electrolytic region formed in the center of a first surface of the conductive plate; and a supply manifold formed on the outer periphery surrounding the central part of the first surface and penetrating the conductive plate, wherein the insulating layer comprises: a first covering portion covering the inner circumferential surface of the supply manifold; and a second covering portion forming a groove-shaped supply passage connecting the supply manifold to the electrolytic region, wherein the electrolytic region is exposed from the insulating layer.

2. The separator according to claim 1, wherein the conductive plate has a groove extending from the edge of the supply manifold toward the electrolytic region, and the inner circumferential surface of the groove is covered by the second covering portion.

3. The separator according to claim 1, wherein the portion of the conductive plate on which the supply path is formed is a flat surface.

4. The separator according to any one of claims 1 to 3, wherein the insulating layer comprises a third covering portion extending from the first covering portion to the second surface of the conductive plate, and the second surface is the surface opposite to the first surface.

5. The separator according to any one of claims 1 to 4, wherein the minimum thickness of the insulating layer is 1 μm or more.

6. The separator according to any one of claims 1 to 5, wherein the second covering portion extends to the periphery of the supply manifold and the periphery of the supply passage on the first surface.

7. The separator according to claim 6, wherein the second coating portion is formed over the entire surface of the first surface excluding the electrolytic region.

8. The separator according to any one of claims 1 to 7, wherein the supply path comprises a slit portion extending from the supply manifold toward the electrolytic region, and a rectifier portion connected to the end of the slit portion and along the supply edge in the electrolytic region.

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

10. The separator according to any one of claims 1 to 9, wherein the material of the insulating layer is a polymer material.

11. The separator according to any one of claims 1 to 10, wherein the conductive plate is formed at a position on the outer periphery different from the supply manifold and comprises a discharge manifold that penetrates the conductive plate, and the insulating layer comprises a fourth covering portion that covers the inner circumferential surface of the discharge manifold and a fifth covering portion that forms a groove-shaped discharge passage connecting the electrolytic region to the discharge manifold.

12. The separator according to any one of claims 1 to 11, wherein the second covering portion comprises a protrusion that protrudes from the bottom of the supply passage.

13. The separator according to any one of claims 1 to 12, wherein the insulating layer is a vapor-deposited layer or a coated layer.

14. The separator according to any one of claims 1 to 12, comprising an adhesive layer for bonding the conductive plate and the insulating layer.

15. An electrolytic cell comprising: an anode section through which a conductive fluid flows; a cathode section from 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 the separator described in any one of claims 1 to 14.

16. The electrolytic cell according to claim 15, wherein the conductive fluid is an alkaline aqueous solution and the electrolyte membrane is an anion exchange membrane.

17. A hydrogen production apparatus comprising a cell module in which multiple electrolytic cells are connected in series, wherein each of the multiple electrolytic cells is an electrolytic cell according to claim 15 or claim 16.

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