JP5525195B2 - High-pressure water electrolyzer and method for manufacturing anode-side power feeder for high-pressure water electrolyzer - Google Patents

Description

  In the present invention, an anode-side power feeder and a cathode-side power feeder are provided on both sides of the electrolyte membrane, and a first flow path for supplying water is formed between the anode-side power feeder and one separator, A high-pressure water electrolysis apparatus and a high-pressure water electrolysis apparatus in which a second flow path is formed between the cathode-side power feeder and the other separator to electrolyze the water to obtain hydrogen having a pressure higher than the pressure of the water The present invention relates to a method for manufacturing an anode-side power feeder.

  For example, in a polymer electrolyte fuel cell, a fuel gas (a gas containing mainly hydrogen, such as hydrogen gas) is supplied to the anode side electrode, while an oxidant gas (mainly containing oxygen) is supplied to the cathode side electrode. By supplying a gas (for example, air), direct current electric energy is obtained.

  In general, a water electrolysis apparatus is employed to produce hydrogen gas that is a fuel gas. This water electrolysis apparatus uses a solid polymer electrolyte membrane (ion exchange membrane) in order to decompose water and generate hydrogen (and oxygen). Electrode catalyst layers are provided on both sides of the solid polymer electrolyte membrane to form an electrolyte membrane / electrode structure, and a power feeder is provided on both sides of the electrolyte membrane / electrode structure. It is configured. That is, the unit is configured substantially in the same manner as the above fuel cell.

  Therefore, in a state where a plurality of units are stacked, a voltage is applied to both ends in the stacking direction, and water is supplied to the anode-side power feeding body. For this reason, water is decomposed and hydrogen ions (protons) are generated on the anode side of the electrolyte membrane / electrode structure, and the hydrogen ions permeate the solid polymer electrolyte membrane and move to the cathode side to bond with electrons. Thus, hydrogen is produced. On the other hand, on the anode side, oxygen produced together with hydrogen is discharged from the unit with excess water.

  As this type of equipment, for example, a power feeder disclosed in Patent Document 1 is known. In this patent document 1, as shown in FIG. 7, the double structure electric power feeding body 3 is comprised by couple | bonding the powder sintering part 1 and the fiber sintering part 2 integrally.

  The powder sintered part 1 is formed by sintering titanium powder, while the fiber sintered part 2 is formed by sintering a titanium fiber sheet. The double structure power feeder 3 is used in a state where the powder sintered portion 1 is in pressure contact with the solid electrolyte membrane 4 in the electrolytic cell of the hydrogen oxygen generator.

JP 2001-279482 A

  However, in Patent Document 1 described above, since the powder sintered portion 1 is formed by sintering titanium powder, the powder sintered portion 1 is likely to have variations in opening due to the aggregation state of the particles, and the diameter of the opening is small. The distribution becomes wide. For this reason, when the double structure power supply 3 is applied to a high pressure water electrolysis apparatus that generates high pressure hydrogen, when the solid electrolyte membrane 4 is brought into pressure contact with the powder sintered portion 1 due to a differential pressure between the anode side and the cathode side. There is a problem that damage such as damage occurs in the solid electrolyte membrane 4.

  The present invention solves this type of problem, and it is possible to prevent damage to the electrolyte membrane as much as possible with a simple configuration and manufacturing process, and anode-side power supply for the high pressure water electrolysis device. It aims at providing the manufacturing method of a body.

In the present invention, an anode-side power feeder and a cathode-side power feeder are provided on both sides of the electrolyte membrane, and a first flow path for supplying water is formed between the anode-side power feeder and one separator, Between the cathode-side power feeder and the other separator, a second flow path is formed in which the water is electrolyzed to obtain hydrogen higher than the pressure of the water, and due to the differential pressure between the anode side and the cathode side The electrolyte membrane is pressed against the anode-side power feeder, and the electrolyte membrane can be damaged due to variations in the opening diameter of the anode-side power feeder, and the anode for the high-pressure water electrolyzer used in the high-pressure water electrolyzer The present invention relates to a method for manufacturing a side power feeder.

In the high-pressure water electrolysis apparatus, the anode-side power feeding body is composed of a porous power feeding body with a porosity of 10 to 50%, and the maximum opening diameter D of the porous power feeding body is the hydrogen on the second flow path side. By setting the pressure P, the thickness t of the electrolyte membrane, and the tensile strength σ of the electrolyte membrane to values having a relationship of D ≦ 4 × t × σ / P, the tensile strength of the electrolyte membrane is set. The tensile stress exceeding the thickness σ is prevented from acting. The porous power supply includes a sheet having a large number of holes on the surface.

Further, in the method for producing an anode-side power supply for a high-pressure water electrolysis apparatus, a porous power supply having a porosity of 10 to 50% is used as the anode-side power supply, and the maximum opening diameter D of the porous power supply is: By setting the hydrogen pressure P on the second flow path side, the thickness t of the electrolyte membrane, and the tensile strength σ of the electrolyte membrane to values having a relationship of D ≦ 4 × t × σ / P The tensile stress exceeding the tensile strength σ is prevented from acting on the electrolyte membrane.

  According to the present invention, the maximum opening diameter of the porous power feeder is set based on the thickness of the electrolyte membrane and the tensile strength and water electrolysis pressure of the electrolyte membrane. Damage can be prevented as much as possible. As a result, it is possible to continuously perform good high-pressure water electrolysis with a simple configuration and manufacturing process.

It is a perspective explanatory view of a water electrolysis device concerning an embodiment of the present invention. It is a partial cross section side view of the water electrolysis device. It is a disassembled perspective explanatory drawing of the unit cell which comprises the said water electrolysis apparatus. It is sectional explanatory drawing of the said unit cell. It is principal part expanded sectional explanatory drawing of the said unit cell. It is explanatory drawing of the relationship between target operation time and the breaking elongation of a film | membrane. It is explanatory drawing of the electric power feeder currently disclosed by patent document 1. FIG.

  As shown in FIG.1 and FIG.2, the water electrolysis apparatus 10 which concerns on embodiment of this invention comprises the high pressure hydrogen production apparatus of a differential pressure type, and the several unit cell 12 is a perpendicular direction (arrow A direction) or A stacked body 14 is stacked in the horizontal direction (arrow B direction). At one end in the stacking direction of the stacked body 14, a terminal plate 16a, an insulating plate 18a, and an end plate 20a are sequentially disposed. Similarly, a terminal plate 16b, an insulating plate 18b, and an end plate 20b are sequentially disposed at the other end of the stacked body 14 in the stacking direction.

  The water electrolysis apparatus 10 integrally clamps and holds the disk-shaped end plates 20a and 20b via a plurality of tie rods 22 extending in the direction of arrow A, for example. The water electrolysis apparatus 10 may employ a configuration in which the water electrolysis apparatus 10 is integrally held by a box-like casing (not shown) including the end plates 20a and 20b as end plates. Moreover, although the water electrolysis apparatus 10 has a substantially cylindrical shape as a whole, it can be set in various shapes such as a cubic shape.

  As shown in FIG. 1, terminal portions 24a and 24b are provided on the side portions of the terminal plates 16a and 16b so as to protrude outward. The terminal portions 24a and 24b are electrically connected to the power source 28 via the wirings 26a and 26b. The terminal portion 24 a on the anode (anode) side is connected to the positive pole of the power source 28, while the terminal portion 24 b on the cathode (cathode) side is connected to the negative pole of the power source 28.

  As shown in FIGS. 2 to 4, the unit cell 12 includes a disc-shaped electrolyte membrane / electrode structure 32, and an anode separator 34 and a cathode separator 36 that sandwich the electrolyte membrane / electrode structure 32. . The anode-side separator 34 and the cathode-side separator 36 have a disk shape, and are made of, for example, a carbon member or the like, or are used for corrosion protection on a steel plate, a stainless steel plate, a titanium plate, an aluminum plate, a plated steel plate, or a metal surface thereof. The metal plate that has been subjected to the above surface treatment is press-molded or cut and subjected to a corrosion-resistant surface treatment.

  The electrolyte membrane / electrode structure 32 includes, for example, a solid polymer electrolyte membrane 38 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode-side power feeder 40 disposed on both sides of the solid polymer electrolyte membrane 38. And a cathode-side power feeder 42.

  An anode electrode catalyst layer 40a and a cathode electrode catalyst layer 42a are formed on both surfaces of the solid polymer electrolyte membrane 38. The anode electrode catalyst layer 40a uses, for example, a Ru (ruthenium) -based catalyst, while the cathode electrode catalyst layer 42a uses, for example, a platinum catalyst.

  The anode-side power supply body 40 and the cathode-side power supply body 42 are made of, for example, a sintered body (porous conductor) of spherical atomized titanium powder. The anode-side power supply body 40 and the cathode-side power supply body 42 are provided with a smooth surface portion that is etched after grinding, and the porosity is set within a range of 10% to 50%, more preferably 20% to 40%. Is done. Note that the anode-side power supply body 40 and the cathode-side power supply body 42 may be formed with openings in a metal sheet such as a corrosion-resistant titanium sheet by etching, drilling, electric discharge machining, electron beam, laser, pressing, or the like.

As shown in FIG. 5, the tensile stress σt acting on the solid polymer electrolyte membrane 38 corresponding to the maximum opening diameter D of the anode-side power feeder 40 is expressed by the relational expression σt = load / π × D × film thickness. Calculated. Further, the thickness t of the high-pressure hydrogen gas pressure P and the solid polymer electrolyte membrane 38, σt = (π × D 2/4) × P ÷ (π × D × t) ≦ σ (σ: a solid polymer electrolyte The tensile strength of the membrane 38 is obtained.

  Thereby, the maximum opening diameter D of the anode side power feeding body 40 is set to a value (usually 30 μm to 200 μm) having a relationship of D ≦ 4 × t × σ / P. And the anode side electric power feeding body 40 is manufactured in the state set to the largest opening diameter D which has said relationship.

  Here, as shown in FIG. 6, even if a stress of σ (MPa) is applied to the solid polymer electrolyte membrane 38, the tensile strength σ is the target operating time for the creep deformation of the solid polymer electrolyte membrane 38. Is set to a value that is maintained in a state where the elongation at break is not reached.

  As shown in FIG. 3, the outer peripheral edge of the unit cell 12 communicates with each other in the direction of arrow A, which is the stacking direction, and a water supply communication hole 46 for supplying water (pure water) and generated by reaction A discharge communication hole 48 for discharging the generated oxygen and used water and a hydrogen communication hole 50 for flowing hydrogen (high-pressure hydrogen) generated by the reaction are provided.

  As shown in FIGS. 3 and 4, a supply passage 52 a that communicates with the water supply communication hole 46 and a discharge passage 52 b that communicates with the discharge communication hole 48 are provided at the outer peripheral edge of the anode separator 34. A first flow path 54 communicating with the supply passage 52a and the discharge passage 52b is provided on the surface 34a of the anode separator 34 facing the electrolyte membrane / electrode structure 32. The first flow path 54 is provided in a range corresponding to the surface area of the anode-side power feeding body 40, and includes a plurality of flow path grooves, a plurality of embosses, and the like (see FIGS. 2 and 4).

  A discharge passage 56 communicating with the hydrogen communication hole 50 is provided at the outer peripheral edge of the cathode separator 36. A second flow path 58 communicating with the discharge passage 56 is formed on the surface 36 a of the cathode separator 36 facing the electrolyte membrane / electrode structure 32. The second flow path 58 is provided within a range corresponding to the surface area of the cathode-side power feeding body 42, and includes a plurality of flow path grooves, a plurality of embosses, and the like (see FIGS. 2 and 4).

  The seal members 60a and 60b are integrated with each other around the outer peripheral ends of the anode side separator 34 and the cathode side separator 36. The seal members 60a and 60b include, for example, EPDM, NBR, fluorine rubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene, acrylic rubber, or other seal materials, cushion materials, or packing materials. Used.

  As shown in FIG. 4, a first seal groove 62 a is formed on the surface 36 a of the cathode separator 36 facing the electrolyte membrane / electrode structure 32 so as to go around the outside of the second flow path 58.

  As shown in FIGS. 3 and 4, the surface 36 a has a second seal groove 62 b, a third seal groove 62 c, and a fourth ring around the outside of the water supply communication hole 46, the discharge communication hole 48, and the hydrogen communication hole 50. A seal groove 62d is formed. In the first seal groove 62a to the fourth seal groove 62d, for example, a first seal member 64a to a fourth seal member 64d that are O-rings are disposed.

  On the surface 34a of the anode separator 34 facing the electrolyte membrane / electrode structure 32, a first seal groove 70a is formed around the outside of the first flow path 54 and facing the first seal groove 62a. The surface 34a circulates outside the water supply communication hole 46, the discharge communication hole 48, and the hydrogen communication hole 50, and is opposite to the second seal groove 62b, the third seal groove 62c, and the fourth seal groove 62d. A seal groove 70b, a third seal groove 70c, and a fourth seal groove 70d are formed. The first seal groove 70a to the fourth seal groove 70d accommodate the first seal member 72a to the fourth seal member 72d that are, for example, O-rings.

  As shown in FIGS. 1 and 2, pipes 76a, 76b and 76c communicating with the water supply communication hole 46, the discharge communication hole 48 and the hydrogen communication hole 50 are connected to the end plate 20a. Although not shown, the pipe 76c is provided with a back pressure valve (or electromagnetic valve), and the pressure of hydrogen generated in the hydrogen communication hole 50 can be maintained at a high pressure.

  The operation of the water electrolysis apparatus 10 configured as described above will be described below.

  As shown in FIG. 1, water is supplied from a pipe 76a to the water supply communication hole 46 of the water electrolysis apparatus 10, and a power supply 28 electrically connected to the terminal portions 24a and 24b of the terminal plates 16a and 16b is provided. A voltage is applied via Therefore, as shown in FIGS. 3 and 4, in each unit cell 12, water is supplied from the water supply communication hole 46 to the first flow path 54 of the anode side separator 34, and this water is supplied to the anode side power supply body 40. Move along.

  Accordingly, water is decomposed by electricity in the anode electrode catalyst layer 40a, and hydrogen ions, electrons, and oxygen are generated. Hydrogen ions generated by this anodic reaction permeate the solid polymer electrolyte membrane 38 and move to the cathode electrode catalyst layer 42a side, and combine with electrons to obtain hydrogen.

  For this reason, hydrogen flows along the second flow path 58 formed between the cathode side separator 36 and the cathode side power supply body 42. This hydrogen is maintained at a higher pressure than the water supply communication hole 46, and can flow out of the water electrolysis apparatus 10 through the hydrogen communication hole 50. On the other hand, oxygen generated by the reaction and used water flow in the first flow path 54, and these are discharged to the outside of the water electrolysis apparatus 10 along the discharge communication hole 48. The second channel 58 has a higher pressure than the first channel 54.

  In this case, the water electrolysis apparatus 10 constitutes a differential pressure type high-pressure hydrogen production apparatus, and includes a second flow path 58 in which high-pressure hydrogen gas is generated and a normal pressure first flow path 54 through which water and oxygen flow. The solid polymer electrolyte membrane 38 is pressed toward the anode-side power feeder 40 (see FIG. 5).

  At this time, in this embodiment, the maximum opening diameter D of the anode-side power feeder 40 is determined by the tensile strength σ of the solid polymer electrolyte membrane 38, the film thickness t of the solid polymer electrolyte membrane 38, and the gas pressure of high-pressure hydrogen ( With respect to (hydrogen pressure) P, a value having a relationship of D ≦ 4 × t × σ / P is set.

  For this reason, stress exceeding the strength (tensile strength σ) of the solid polymer electrolyte membrane 38 does not act on the solid polymer electrolyte membrane 38. Therefore, the solid polymer electrolyte membrane 38 can be deformed along the shape of the opening of the anode-side power feeder 40, and can be reliably prevented from being deformed to break elongation and causing membrane breakage.

  As shown in FIG. 6, even if the stress σ acts on the solid polymer electrolyte membrane 38, the creep deformation of the solid polymer electrolyte membrane 38 is maintained in a state where it does not reach the breaking elongation until the target operation time. It is.

  Thereby, the water electrolysis apparatus 10 can prevent the solid polymer electrolyte membrane 38 from being damaged as much as possible with a simple configuration and a manufacturing process, and can continuously perform a good water electrolysis process. The effect is obtained.

DESCRIPTION OF SYMBOLS 10 ... Water electrolysis apparatus 12 ... Unit cell 14 ... Laminated body 16a, 16b ... Terminal plate 18a, 18b ... Insulation plate 20a, 20b ... End plate 24a, 24b ... Terminal part 28 ... Power supply 32 ... Electrolyte membrane and electrode structure 34 ... Anode-side separator 36 ... Cathode-side separator 38 ... Solid polymer electrolyte membrane 40 ... Anode-side power feeder 42 ... Cathode-side power feeder

Claims (2)

An anode-side feeder and a cathode-side feeder are provided on both sides of the electrolyte membrane, and a first flow path for supplying water is formed between the anode-side feeder and one separator, and the cathode-side feeder Between the first separator and the other separator, a second flow path is formed in which the water is electrolyzed to obtain hydrogen higher than the pressure of the water, and the electrolyte membrane is formed by the differential pressure between the anode side and the cathode side. A high-pressure water electrolysis apparatus that is pressed against the anode-side power feeder and can damage the electrolyte membrane due to variations in the opening diameter of the anode-side power feeder;
The anode power feeding body is composed of a porous power feeding body with a porosity of 10 to 50% ,
The maximum opening diameter D of the porous power feeder is such that D ≦ 4 × t × σ / with respect to the hydrogen pressure P on the second flow path side, the thickness t of the electrolyte membrane, and the tensile strength σ of the electrolyte membrane. A high-pressure water electrolysis apparatus characterized in that a tensile stress exceeding the tensile strength σ acts on the electrolyte membrane by being set to a value having a relationship of P. An anode-side feeder and a cathode-side feeder are provided on both sides of the electrolyte membrane, and a first flow path for supplying water is formed between the anode-side feeder and one separator, and the cathode-side feeder Between the first separator and the other separator, a second flow path is formed in which the water is electrolyzed to obtain hydrogen higher than the pressure of the water, and the electrolyte membrane is formed by the differential pressure between the anode side and the cathode side. A method for producing an anode-side power supply for a high-pressure water electrolysis apparatus used in a high-pressure water electrolysis apparatus that is pressed against the anode-side power supply and can damage the electrolyte membrane due to variations in the opening diameter of the anode-side power supply,
While using a porous power supply with a porosity of 10 to 50% as the anode-side power supply,
The maximum opening diameter D of the porous power feeder is such that D ≦ 4 × t × σ / with respect to the hydrogen pressure P on the second flow path side, the thickness t of the electrolyte membrane, and the tensile strength σ of the electrolyte membrane. A method for producing an anode-side power feeder for a high-pressure water electrolysis apparatus, wherein a tensile stress exceeding the tensile strength σ acts on the electrolyte membrane by being set to a value having a relationship of P .

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