JP2011208163A - Water electrolyzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily make a sealing member compact and to successfully obtain high pressure hydrogen.SOLUTION: A unit cell 12 constituting a water electrolyzer 10 has an electrolyte membrane/electrode structure 32 held between an anode side separator 34 and a cathode side separator 36. A water supply communicating hole 50a, a discharge communicating hole 50b and a high pressure hydrogen communicating hole 50c are formed respectively in a first projection 48a, a second projection 48b and a third projection 48c. In the third projection 48c, a first positioning hole 70a is formed adjacently to the high pressure hydrogen communicating hole 50c. In the first projection 48a, a second positioning hole part 70b is formed adjacently to the water supply communicating hole 50a. The first positioning hole part 70a is set with higher dimensional accuracy than that of the second positioning hole part 70b.

Description

  In the present invention, a power feeding body is provided on both sides of the electrolyte membrane, a separator is stacked on the power feeding body, and a water flow path for supplying water is formed between one power feeding body and one separator, A unit cell in which a high-pressure hydrogen flow path for obtaining high-pressure hydrogen higher than normal pressure is formed by electrolyzing the water between the other power supply body and the other separator is provided. The present invention relates to a laminated water electrolysis apparatus.

  For example, 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 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.

  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 water electrolysis apparatus disclosed in Patent Document 1 is known. In this water electrolysis apparatus, as shown in FIG. 8, a plurality of cells 2 in which a solid polymer electrolyte membrane is sandwiched between a disc-shaped anode power feeding plate 1 and a cathode power feeding plate are polymerized via a separation plate. The anode power feeding plate 1 is fitted on a casing ring 3 that constitutes a casing.

  A plurality of grooves 4 are provided in parallel to each other on the surface of the anode power supply plate 1 that does not contact the electrolyte membrane. Each groove 4 constitutes a pure water flow path and also a flow path through which the generated oxidant gas flows. A circumferential groove 5 communicating with the groove 4 is formed on the inner peripheral surface of the casing ring 3, and three through holes 6a, 6b, and 6c are formed through the lamination direction.

  Between the through hole 6a for supplying pure water and the circumferential groove 5, and between the through hole 6b for discharging pure water and oxygen gas and the circumferential groove 5, there are through holes 7a and 7b for communicating these. Is formed. The through hole 6c for discharging hydrogen gas is provided close to the through hole 6b side, and hydrogen generated in the cathode power supply plate by electrolysis of water is led out to the through hole 6c.

JP-A-9-95791

  By the way, in said water electrolysis apparatus, high pressure hydrogen, such as 35 Mpa, may be obtained, for example. At that time, since high-pressure hydrogen flows through the through hole 6c for discharging hydrogen gas, pressure resistance is required for the seal member for sealing the through hole 6c, and the thickness of the seal member is set large. There is a need to.

  In particular, although not shown, the casing ring 3 is laminated with other casing rings and cells, and therefore, a deviation is easily generated between the respective through holes 6c. Therefore, the dimension of the seal member must be set large in accordance with the deviation between the through holes 6c. Thereby, in order to maintain a pressure | voltage resistance, the thickness of a sealing member will increase and there exists a problem that the whole water electrolysis apparatus enlarges.

  The present invention solves this type of problem, and an object thereof is to provide a water electrolysis apparatus capable of easily reducing the size of a seal member and obtaining high-pressure hydrogen satisfactorily.

  In the present invention, a power feeding body is provided on both sides of the electrolyte membrane, a separator is stacked on the power feeding body, and a water flow path for supplying water is formed between one power feeding body and one separator, A unit cell in which a high-pressure hydrogen flow path for obtaining high-pressure hydrogen higher than normal pressure is formed by electrolyzing the water between the other power supply body and the other separator is provided. The present invention relates to a laminated water electrolysis apparatus.

  This water electrolysis apparatus extends in the stacking direction of the unit cells and supplies water to the water flow path, and extends in the stacking direction of the unit cells, and generates the remaining water from the water flow path. A discharge communication hole for discharging oxygen and a high-pressure hydrogen communication hole extending in the stacking direction of the unit cells and discharging high-pressure hydrogen from the high-pressure hydrogen flow path are provided.

  The water electrolysis apparatus is adjacent to the high pressure hydrogen communication hole, adjacent to the first positioning hole portion into which the first positioning member is inserted, and to the water communication hole or discharge communication hole, and is inserted into the second positioning member. The first positioning hole is set with higher dimensional accuracy than the second positioning hole.

  In addition, the water electrolysis apparatus is configured such that a plurality of unit cells are positioned and held by the first positioning member and the second positioning member to form a water electrolysis unit, and each water electrolysis unit is configured to be adjacent to each other separator Are at least a first connection hole and a second connection hole into which at least the first unit connection member and the second unit connection member are inserted at positions different from the first positioning hole and the second positioning hole. Preferably it is formed.

  Furthermore, in this water electrolysis apparatus, it is preferable that the opening size of the high-pressure hydrogen communication hole is set to be smaller than the opening size of the water communication hole and the opening size of the discharge communication hole.

  According to the present invention, the first positioning hole adjacent to the high-pressure hydrogen communication hole is set with higher dimensional accuracy than the second positioning hole adjacent to the water communication hole or the discharge communication hole. For this reason, when the unit cells are configured by stacking the separators and when the plurality of unit cells are stacked, the high-pressure hydrogen communication holes are positioned with high accuracy.

  Therefore, the sealing member that seals each high-pressure hydrogen communication hole is made as compact as possible, and the wall thickness necessary for ensuring pressure resistance can be set small. Thereby, the whole water electrolysis apparatus can be easily reduced in size and thickness.

  Moreover, the dimensional accuracy of the second positioning hole is set lower than that of the first positioning hole. For this reason, it is possible to easily insert the second positioning member into the second positioning hole in a state where the first positioning member is inserted into the first positioning hole having a severe dimensional tolerance. Therefore, the assembly workability of the water electrolysis apparatus is improved satisfactorily.

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. FIG. 4 is a cross-sectional view of the unit cell taken along line IV-IV in FIG. 3. It is front explanatory drawing of the anode side separator which comprises the said unit cell. It is a schematic perspective explanatory drawing of the water electrolysis unit which comprises the said water electrolysis apparatus. It is front explanatory drawing of the said anode side separator which comprises the edge part separator of the said water electrolysis unit. 10 is an explanatory diagram of a cell disclosed in 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 a high voltage | pressure hydrogen production apparatus. The water electrolysis apparatus 10 includes a water electrolysis unit 14a in which a plurality of unit cells 12 are laminated in a vertical direction (arrow A direction) or a horizontal direction (arrow B direction), and the water electrolysis unit 14a is laminated to form a laminate. 14 is configured.

  At one end (upper 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 upward. Similarly, a terminal plate 16b, an insulating plate 18b, and an end plate 20b are sequentially disposed on the other end (lower end) in the stacking direction of the stacked body 14 in a downward direction.

  The water electrolysis apparatus 10 integrally holds and holds the disc-shaped end plates 20a and 20b via four 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 part 24 a on the cathode (cathode) side is connected to the negative pole of the power supply 28, while the terminal part 24 b on the anode (anode) side is connected to the positive pole of the power supply 28.

  As shown in FIGS. 2 to 4, the unit cell 12 includes a substantially disc-shaped electrolyte membrane / electrode structure 32, an anode-side separator (one separator) 34 and a cathode that sandwich the electrolyte membrane / electrode structure 32. Side separator (the other separator) 36. The anode-side separator 34 and the cathode-side separator 36 have a substantially disk shape and are made of, for example, a carbon member or the like, or a steel plate, a stainless steel plate, a titanium plate, an aluminum plate, a plated steel plate, or a metal surface thereof A metal plate subjected to an edible surface treatment is press-molded or cut and subjected to an anticorrosive 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 a circular anode-side power feeder provided on both surfaces of the solid polymer electrolyte membrane 38. (First power supply body) 40 and cathode side power supply body (second power supply body) 42 are provided. The peripheral edge of the solid polymer electrolyte membrane 38 protrudes outward from the outer periphery of the anode-side power supply body 40 and the cathode-side power supply body 42 (see FIGS. 3 and 4).

  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.

  The anode power feeding body 40 is fitted to the inner peripheral surface of the ring-shaped frame member 43. The frame member 43 is made of pure titanium, for example. A flow path plate 44 is interposed between the anode side separator 34, the anode side power feeder 40 and the frame member 43. The flow path plate 44 has a plurality of holes or openings, or is made of a porous conductor.

  As shown in FIG. 4, a load applying mechanism 45 that presses the cathode side power supply body 42 against the solid polymer electrolyte membrane 38 is provided between the cathode side power supply body 42 and the cathode side separator 36. The load applying mechanism 45 includes a disc spring 46, and the disc spring 46 applies a load to the cathode-side power feeder 42 via the disc spring holder 47.

  As shown in FIG. 3, a first protrusion 48 a, a second protrusion 48 b, and a third protrusion 48 c that protrude outward in the separator surface direction are formed on the outer periphery of the unit cell 12. The first protrusion 48a is provided with a water supply communication hole 50a that communicates with each other in the direction of arrow A, which is the stacking direction, and supplies water (pure water).

  The second projecting portion 48b is provided with a discharge communication hole 50b that communicates with each other in the direction of the arrow A and discharges oxygen generated by the reaction and used water. The third protrusion 48c is provided with a high-pressure hydrogen communication hole 50c that is in communication with each other in the direction of arrow A, which is the stacking direction, for flowing high-pressure hydrogen generated by the reaction.

  The high-pressure hydrogen communication hole 50c has a circular shape, while the water supply communication hole 50a and the discharge communication hole 50b have an oval shape. The opening size of the high-pressure hydrogen communication hole 50c is set to be smaller than the opening size of the water supply communication hole 50a and the opening size of the discharge communication hole 50b.

  As shown in FIGS. 3 and 4, the anode-side separator 34 is provided with a supply passage 52a that communicates with the water supply communication hole 50a and a discharge passage 52b that communicates with the discharge communication hole 50b. A surface 34a of the anode separator 34 facing the electrolyte membrane / electrode structure 32 is provided with a first flow path (water flow path) 54 communicating with the supply passage 52a and the discharge passage 52b. The first flow path 54 is provided in a range corresponding to a contact area range in contact with the solid polymer electrolyte membrane 38 of the anode power supply body 40.

  The cathode-side separator 36 is provided with a discharge passage 56 that communicates with the high-pressure hydrogen communication hole 50c. A second flow path (high-pressure hydrogen 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 in a range corresponding to the contact area range of the cathode-side power feeder 42.

  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 FIGS. 3 and 4, the surface 34 a of the anode-side separator 34 facing the electrolyte membrane / electrode structure 32 circulates outward from the first flow path 54 and the anode-side power feeding body 40, and thus the second seal. A second seal groove 64a for disposing the member 62a is formed.

  On the surface 34a, the third seal member 62b, the fourth seal member 62c, and the fifth seal member 62d are arranged around the outside of the water supply communication hole 50a, the discharge communication hole 50b, and the high-pressure hydrogen communication hole 50c. A third seal groove 64b, a fourth seal groove 64c, and a fifth seal groove 64d are formed. The second seal member 62a to the fifth seal member 62d are, for example, O-rings.

  On the surface 36a of the cathode side separator 36 facing the electrolyte membrane / electrode structure 32, the second seal 58a is disposed for circulating the second flow path 58 and the cathode side power supply body 42 outward. One seal groove 68a is formed.

  On the surface 36a, the third seal member 66b, the fourth seal member 66c, and the fifth seal member 66d are disposed around the outside of the water supply communication hole 50a, the discharge communication hole 50b, and the hydrogen communication hole 50c. A third seal groove 68b, a fourth seal groove 68c, and a fifth seal groove 68d are formed. The first seal member 66a, the third seal member 66b to the fifth seal member 66d are, for example, O-rings.

  The second seal groove 64a that goes around the outside of the anode-side power supply body 40 and the first seal groove 68a that goes around the outside of the cathode-side power supply body 42 are solid polymer in the separator stacking direction (arrow A direction). The positions are set different from each other with the electrolyte membrane 38 interposed therebetween.

  The fifth seal groove 64d that circulates outward from the high-pressure hydrogen communication hole 50c and the fifth seal groove 68d that circulates outward from the high-pressure hydrogen communication hole 50c form the solid polymer electrolyte membrane 38 in the direction of arrow A. The positions are set different from each other.

  As shown in FIGS. 3 and 5, the anode-side separator 34 is provided with a first positioning hole (knock hole) 70a adjacent to the high-pressure hydrogen communication hole 50c in the third protrusion 48c, and the first A second positioning hole (knock hole) 70b is formed in the protrusion 48a adjacent to the water supply communication hole 50a.

  A first positioning pin (first positioning member) (knock pin) 72a is inserted into the first positioning hole 70a, while a second positioning pin (second positioning member) (knock pin) is inserted into the second positioning hole 70b. ) 72b is inserted (see FIG. 3). The first positioning hole 70a is set with higher dimensional accuracy than the second positioning hole 70b. That is, the first positioning hole 70a is set with a stricter dimensional tolerance than the second positioning hole 70b.

  The cathode side separator 36 and the electrolyte membrane / electrode structure 32 are similarly formed with a first positioning hole 70a and a second positioning hole 70b. Further, the second positioning hole portion 70b may be formed adjacent to the discharge communication hole 50b in the second protrusion portion 48b instead of the first protrusion portion 48a.

  The first positioning pins 72a and the second positioning pins 72b are integrally inserted into a predetermined number of unit cells 12 to position and hold the unit cells 12 to constitute the water electrolysis unit 14a.

  As shown in FIG. 6, each water electrolysis unit 14a has an anode side separator 34E and a cathode side separator 36E which are adjacent to each other. As shown in FIGS. 6 and 7, in the anode side separator 34E and the cathode side separator 36E, a first connecting hole portion 74a is formed in the third projecting portion 48c at a position different from the first positioning hole portion 70a. At the same time, a second connection hole 74b is formed in the second protrusion 48b.

  In the anode side separator 34E and the cathode side separator 36E, a unit connection pin (second unit connection member) 76a is inserted into each first connection hole 74a, while a second unit connection pin ( The second unit connecting member) 76b is inserted. Note that three or more connecting holes and three or more unit connecting pins may be provided.

  As shown in FIGS. 1 and 2, pipes 78a, 78b, and 78c communicating with the water supply communication hole 50a, the discharge communication hole 50b, and the high-pressure hydrogen communication hole 50c are connected to the end plate 20a. Although not shown, the pipe 78c is provided with a back pressure valve (or electromagnetic valve), and the pressure of hydrogen generated in the high-pressure hydrogen communication hole 50c can be maintained at a high pressure. A pressing force is applied between the end plates 20 a and 20 b by a pressing force applying device (not shown), and the end plates 20 a and 20 b are tightened via the tie rods 22 in this state.

  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 78a to the water supply communication hole 50a 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 FIG. 3 and FIG. 4, in each unit cell 12, water is supplied from the water supply communication hole 50 a to the first flow path 54 of the anode side separator 34, and this water is inside 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 separator 36 and the cathode power supply body 42. This hydrogen is maintained at a pressure higher than that of the water supply communication hole 50a, and can flow out of the water electrolysis apparatus 10 through the high-pressure hydrogen communication hole 50c. On the other hand, oxygen generated by the reaction and used water flow through the first flow path 54, and these are discharged to the outside of the water electrolysis apparatus 10 along the discharge communication hole 50b.

  In this case, in the first embodiment, the anode separator 34 is provided with the first positioning hole portion 70a adjacent to the hydrogen communication hole 50c in the third protrusion portion 48c and the first protrusion portion 48a with water. A second positioning hole 70b is formed adjacent to the supply communication hole 50a. The dimensional tolerance of the first positioning hole 70a is set to be stricter than that of the second positioning hole 70b.

  Therefore, when the unit cell 12 is configured by stacking the anode side separator 34 and the cathode side separator 36 with the electrolyte membrane / electrode structure 32 interposed therebetween, and when the unit cell 12 is stacked, the water electrolysis unit When 14a is constructed, the high-pressure hydrogen communication holes 50c are positioned with high accuracy.

  Therefore, as shown in FIG. 4, the fifth seal member 62d and the fifth seal member 66d that seal the high-pressure hydrogen communication hole 50c can be brought close to each other, and the fifth seal groove 64d and the fifth seal groove 68d The interval S is set as close as possible. This is because the deviation width between the anode-side separator 34 and the cathode-side separator 36 with respect to the high-pressure hydrogen communication hole 50c is satisfactorily reduced.

  For this reason, the fifth seal member 62d and the fifth seal member 66d are effectively made compact, and the wall thickness necessary to ensure pressure resistance can be set small. Thereby, the effect that size reduction and thickness reduction of the water electrolysis apparatus 10 whole are achieved easily is acquired.

  In addition, the second positioning hole 70b is set to have a lower dimensional accuracy than the first positioning hole 70a. For this reason, it is possible to easily insert the second positioning member 72b into the second positioning hole portion 70b in a state where the first positioning member 72a is inserted into the first positioning hole portion 70a having a severe dimensional tolerance. . Therefore, the assembly workability of the water electrolysis apparatus 10 is improved satisfactorily.

  Furthermore, as shown in FIG. 6, each water electrolysis unit 14a has an anode side separator 34E and a cathode side separator 36E which are adjacent to each other. In the anode separator 34E and the cathode separator 36E, the first unit connection pin 76a is inserted into each first connection hole 74a, while the second first unit connection pin 76a is inserted into each second connection hole 74b. By being inserted, it is positioned and held integrally.

  Thereby, each water electrolysis unit 14a is integrated easily and correctly, and the advantage that the assembly operation | work of the laminated body 14, ie, the assembly operation of the whole water electrolysis apparatus 10, is performed efficiently is acquired.

DESCRIPTION OF SYMBOLS 10 ... Water electrolysis apparatus 12 ... Unit cell 14 ... Laminated body 14a ... Water electrolysis unit 16a, 16b ... Terminal plate 18a, 18b ... Insulation plate 20a, 20b ... End plate 24a, 24b ... Terminal part 28 ... Power supply 32 ... Electrolyte membrane * Electrode structures 34, 34E ... anode side separator 36, 36E ... cathode side separator 38 ... solid polymer electrolyte membrane 40 ... anode side power supply body 40a ... anode electrode catalyst layer 42 ... cathode side power supply body 42a ... cathode electrode catalyst layer 48a, 48b, 48c ... Projection 50a ... Water supply communication hole 50b ... Discharge communication hole 50c ... High pressure hydrogen communication hole 54, 58 ... Flow path 60a, 60b, 62a, 62b, 62c, 62d, 66a, 66b, 66c, 66d ... Seal Members 64a, 64b, 64c, 64d, 68a, 68b, 68c, 68 ... seal groove 70a, 70b ... positioning holes 72a, 72b ... positioning pins 74a, 74b ... connecting holes 76a, 76 b ... unit connecting pin

Claims (3)

A power feeding body is provided on both sides of the electrolyte membrane, a separator is stacked on the power feeding body, and a water flow path for supplying water is formed between one power feeding body and one separator, and the other power feeding body A unit cell in which a high-pressure hydrogen flow path for obtaining high-pressure hydrogen that is higher than normal pressure is obtained by electrolyzing the water between the first separator and the other separator, and in which the plurality of unit cells are stacked An electrolysis device,
A water communication hole extending in the stacking direction of the unit cells and supplying the water to the water flow path;
A discharge communication hole extending in the stacking direction of the unit cells and discharging the remaining water and generated oxygen from the water flow path;
A high-pressure hydrogen communication hole extending in the stacking direction of the unit cells and discharging the high-pressure hydrogen from the high-pressure hydrogen flow path;
Provided,
A first positioning hole adjacent to the high-pressure hydrogen communication hole and into which the first positioning member is inserted;
A second positioning hole portion adjacent to the water communication hole or the discharge communication hole and into which a second positioning member is inserted;
And having
The water electrolysis apparatus, wherein the first positioning hole is set with higher dimensional accuracy than the second positioning hole. The water electrolysis apparatus according to claim 1, wherein a plurality of unit cells are positioned and held by the first positioning member and the second positioning member to form a water electrolysis unit,
At least a first unit connecting member and a second unit connecting member are inserted into the separators constituting each water electrolysis unit and adjacent to each other at positions different from the first positioning hole and the second positioning hole. A water electrolysis apparatus, wherein at least a first connection hole and a second connection hole are formed.   3. The water electrolysis apparatus according to claim 1, wherein an opening size of the high-pressure hydrogen communication hole is set to be smaller than an opening size of the water communication hole and an opening size of the discharge communication hole. Water electrolyzer.

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