JP2011127212A - Water electrolyzer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water electrolyzer capable of excellently reducing the pressure loss of a water channel and efficiently and economically passing water with a simple structure. <P>SOLUTION: A unit cell 12 constituting the water electrolyzer 10 is provided with an electrolyte membrane/electrode structure 32 which is held between an anode side separator 34 and a cathode side separator 36. The anode side separator 34 is provided with a plurality of inlet connection channel 52a communicating with a water supply communication hole 46 and a plurality of outlet connection channel 52b communicating with a discharge communication hole 48. The cross-section of the channel of the discharge connection channel 52 is set to be larger than the cross section of the channel of the inlet connection channel 52a. <P>COPYRIGHT: (C)2011,JPO&INPIT

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, The present invention relates to a water electrolysis apparatus including a unit cell in which a hydrogen flow path for obtaining hydrogen by electrolyzing the water is formed between the other power feeding body and the other separator, and a plurality of the unit cells are stacked.

  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 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 water electrolysis apparatus disclosed in Patent Document 1 is known. In this water electrolysis apparatus, as shown in FIG. 7, 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 the above water electrolysis apparatus, downstream of each groove 4, oxygen (reactive gas) generated by the reaction in addition to unreacted water also circulates. For this reason, in the through-hole 7b, the two-phase flow of water and oxygen exists, and the volume rapidly increases due to the generation of gas.

  Therefore, the pressure loss of the through hole 7b is increased as compared with the pressure loss of the through hole 7a where only water exists. Thereby, the pressure loss as the whole water electrolysis apparatus becomes high, a high output and high performance water pump is needed, and there is a problem that it is not economical.

  The present invention solves this type of problem, and can easily reduce the pressure loss of the water flow path with a simple configuration, and can efficiently and economically distribute water. The purpose is to provide.

  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, The present invention relates to a water electrolysis apparatus comprising a unit cell in which a hydrogen flow path for obtaining hydrogen by electrolyzing the water is formed between the other power feeding body and the other separator, and a plurality of the unit cells are stacked. It is.

  This water electrolysis device 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 the remaining water and generation from the water flow path A discharge communication hole for discharging the generated oxygen; an inlet connection flow path for communicating the water supply communication hole and the water flow path; and an outlet connection flow path for communicating the discharge communication hole and the water flow path. Yes. The channel cross-sectional area of the outlet connection channel is set larger than the channel cross-sectional area of the inlet connection channel.

  Moreover, it is preferable that the inlet connection channel and the outlet connection channel have a circular opening cross section, and the outlet connection channel is set to have a larger number or a larger diameter than the inlet connection channel.

  Further, the unit cells are preferably stacked in the vertical direction, and the water supply communication hole and the discharge communication hole preferably allow water to flow vertically upward.

  According to the present invention, the outlet connection channel that communicates the discharge communication hole and the water channel is set to have a larger channel cross-sectional area than the inlet connection channel that communicates the water supply communication hole and the water channel. Yes.

  Therefore, even if unreacted water and generated oxygen exist on the outlet connection channel side, and an increase in volume occurs, it is possible to prevent an increase in pressure loss in the outlet connection channel. For this reason, it is possible to reduce the pressure loss of the water flow path satisfactorily with a simple configuration, and to circulate water efficiently and economically. Thereby, water can be uniformly and reliably supplied to the entire water flow path, and the water splitting process is satisfactorily performed.

It is a perspective explanatory view of a water electrolysis device concerning a 1st 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 explanatory 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 front explanatory drawing of the anode side separator which comprises the water electrolysis apparatus which concerns on the 2nd Embodiment of this invention. It is explanatory drawing of the water electrolysis apparatus currently disclosed by patent document 1. FIG.

  As shown in FIG.1 and FIG.2, the water electrolysis apparatus 10 which concerns on the 1st Embodiment of this invention comprises the high voltage | pressure hydrogen production apparatus, and the several unit cell 12 is a perpendicular direction (arrow A direction). A laminated body 14 is provided.

  At the 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 at the lower end in the stacking direction of the stacked body 14 in the 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 four tie rods 22 are arranged at equal angles from each other with respect to the centers of the end plates 20a and 20b.

  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, the water electrolysis apparatus 10 has a substantially cylindrical shape as a whole.

  Terminal portions 24a and 24b are provided on the side portions of the terminal plates 16a and 16b so as to protrude outward. As shown in FIG. 1, the terminal portions 24a and 24b are electrically connected to a power source 28 via 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 and 3, the unit cell 12 includes a substantially disc-shaped electrolyte membrane / electrode structure 32, and an anode-side separator 34 and a cathode-side separator 36 that sandwich the electrolyte membrane / electrode structure 32. Prepare. 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 feeder 40 provided on both surfaces of the solid polymer electrolyte membrane 38. And a circular cathode side power supply body 42. The peripheral edge of the solid polymer electrolyte membrane 38 protrudes outward from the outer peripheries of the anode side power supply body 40 and the cathode side power supply body 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.

  As shown in FIG. 3, a first protrusion 44 a, a second protrusion 44 b, and a third protrusion 44 c that protrude outward in the separator surface direction are formed on the outer periphery of the unit cell 12. The first protrusion 44 a is provided with a water supply communication hole 46 for supplying water (pure water) in communication with each other in the direction of arrow A, which is the stacking direction.

  The second projecting portion 44b is provided with a discharge communication hole 48 that communicates with each other in the direction of the arrow A and discharges oxygen generated by the reaction and used water. The third projecting portion 44c is provided with a hydrogen communication hole 50 that communicates with each other in the direction of arrow A, which is the stacking direction, for flowing hydrogen generated by the reaction. The water supply communication hole 46 and the discharge communication hole 48 have an elliptical cross section of the opening cross section, and are disposed at positions that are point-symmetric with each other.

  As shown in FIGS. 3 and 5, the anode-side separator 34 has a plurality (for example, three) of inlet connection channels 52 a communicating with the water supply communication holes 46 and a plurality (for example, for example) communicating with the discharge communication holes 48. 5) outlet connection channels 52b. The inlet connection flow path 52a and the outlet connection flow path 52b have an opening cross-sectional circular shape and are arranged in parallel to each other (see FIG. 5). The outlet connection channel 52b may be set to have a larger number than the inlet connection channel 52a, and the number of each may be arbitrarily set.

  The water supply communication hole 46 has an oval cross section with an elongated communication hole inner wall surface 46a in which a plurality of inlet connection channels 52a are opened and a communication hole outer wall surface 46b opposite to the communication hole inner wall surface 46a. The discharge communication hole 48 has an oval cross section with an elongated communication hole inner wall surface 48a in which a plurality of outlet connection channels 52b are opened and a communication hole outer wall surface 48b opposite to the communication hole inner wall surface 48a.

  A water flow path 54 communicating with the inlet connection flow path 52a and the outlet connection flow path 52b is provided on a surface 34a of the anode separator 34 facing the electrolyte membrane / electrode structure 32.

  As shown in FIG. 5, the water flow path 54 extends in the direction of the power supply body parallel to the virtual straight line (diameter) connecting the water supply communication hole 46 and the discharge communication hole 48, and is in the plane of the anode-side power supply body 40. A plurality of water passages 56 arranged in parallel, the outer side of the anode side power supply body 40, and an arcuate inlet buffer portion 58 a that communicates with the water supply communication hole 46 and the outer side of the anode side power supply body 40. An arcuate outlet buffer portion 58b that circulates and communicates with the discharge communication hole 48 is provided.

  One end of each inlet connection channel 52a communicates with the arcuate inlet buffer portion 58a, and one end of each outlet connection channel 52b communicates with the arcuate outlet buffer portion 58b.

  As shown in FIGS. 3 and 4, the cathode separator 36 is provided with a discharge passage 62 communicating with the hydrogen communication hole 50. A hydrogen flow path 64 communicating with the discharge passage 62 is formed on the surface 36 a of the cathode separator 36 facing the electrolyte membrane / electrode structure 32. The hydrogen flow path 64 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 66a and 66b 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 66a and 66b include, for example, EPDM, NBR, fluorine rubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroplane, acrylic rubber, or other seal materials, cushion materials, or packing materials. Used.

  As shown in FIGS. 3 and 4, a first seal groove 68 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 hydrogen flow path 64.

  A second seal groove 68b, a third seal groove 68c, and a fourth seal groove 68d are formed on the surface 36a of the cathode-side separator 36 around the outside of the water supply communication hole 46, the discharge communication hole 48, and the hydrogen communication hole 50. Is done. In the first seal groove 68a to the fourth seal groove 68d, for example, a first seal member 70a to a fourth seal member 70d 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 76a is formed around the outside of the water channel 54 and facing the first seal groove 68a.

  The surface 34a circulates outside the water supply communication hole 46, the discharge communication hole 48, and the hydrogen communication hole 50, and is opposed to the second seal groove 68b, the third seal groove 68c, and the fourth seal groove 68d. A seal groove 76b, a third seal groove 76c, and a fourth seal groove 76d are formed. In the first seal groove 76a to the fourth seal groove 76d, for example, a first seal member 78a to a fourth seal member 78d which are O-rings are accommodated.

  As shown in FIGS. 1 and 2, the end plate 20 b is connected to a pipe 82 a that communicates with the water supply communication hole 46, and the end plate 20 a communicates with a discharge communication hole 48 and a hydrogen communication hole 50. Pipes 82b and 82c are connected. Although not shown, the pipe 82c 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 82a to the water supply communication hole 46 of the water electrolysis apparatus 10 in a vertically upward direction, and is electrically connected to the terminal portions 24a and 24b of the terminal plates 16a and 16b. A voltage is applied via a power supply 28 connected to the. Therefore, as shown in FIG. 3, in each unit cell 12, water is supplied from the water supply communication hole 46 to the water flow path 54 of the anode side separator 34, and this water moves along the anode side power supply body 40. .

  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 hydrogen flow path 64 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 46 and can flow out of the water electrolysis apparatus 10 by flowing vertically through the hydrogen communication hole 50. On the other hand, oxygen generated by the reaction and used water flow in the water flow path 54, and these move vertically along the discharge communication hole 48 and are discharged outside the water electrolysis apparatus 10. Is done.

  In this case, only water is supplied from the water supply communication hole 46 via the inlet connection flow path 52a to the water flow path 54, while from the water flow path 54 to the discharge communication hole 48 via the outlet connection flow path 52b. Water and produced oxygen are exhausted. Therefore, in the outlet connection channel 52b, there is a two-phase flow of water and gas (oxygen), and the volume rapidly increases due to the generation of gas.

  Therefore, in the first embodiment, as shown in FIGS. 3 and 5, the outlet connection flow path 52 b communicating with the discharge communication hole 48 is more than the inlet connection flow path 52 a communicating with the water supply communication hole 46. The number is set. Therefore, even if unreacted water and generated oxygen are present on the outlet connection channel 52b side, and an increase in volume is caused, it is possible to suppress an increase in pressure loss in the outlet connection channel 52b. become.

  For this reason, it is possible to satisfactorily reduce the pressure loss of the water flow path 54 with a simple configuration, and to distribute water efficiently and economically. Thereby, water can be uniformly and reliably supplied to the entire water flow path 54, and the effect that the water splitting process is satisfactorily performed can be obtained.

  FIG. 6 is an explanatory diagram viewed from the front of the anode-side separator 92 constituting the water electrolysis apparatus 90 according to the second embodiment of the present invention. The same components as those of the anode separator 34 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The anode-side separator 92 has a plurality (for example, three) of inlet connection channels 94 a that communicate with the water supply communication holes 46 and a plurality of (for example, three) outlet connection channels 94 b that communicate with the discharge communication holes 48. And are provided. The inlet connection channel 94a and the outlet connection channel 94b have an opening cross-sectional circular shape, and the outlet connection channel 94b is set to have a larger diameter than the inlet connection channel 94a.

  As described above, in the second embodiment, since the outlet connection channel 94b is set to have a larger diameter than the inlet connection channel 94a, the pressure loss of the outlet connection channel 94b is favorably reduced. Thereby, water can be uniformly and reliably supplied to the entire water flow channel 54, and the same effects as those of the first embodiment can be obtained, such as being able to perform the water splitting process satisfactorily.

DESCRIPTION OF SYMBOLS 10, 90 ... 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, 92 ... anode side separator 36 ... cathode side separator 38 ... solid polymer electrolyte membrane 40 ... anode side power supply body 42 ... cathode side power supply bodies 44a to 44c ... projection 46 ... water supply communication hole 48 ... discharge communication hole 50 ... Hydrogen communication holes 52a, 94a ... Inlet connection flow path 52b, 94b ... Outlet connection flow path 54 ... Water flow path 56 ... Water passage 58a ... Arc-shaped inlet buffer section 58b ... Arc-shaped outlet buffer section 62 ... Discharge passage 64 ... Hydrogen flow path

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 water electrolysis apparatus comprising a unit cell in which a hydrogen flow path for obtaining hydrogen by electrolyzing the water is formed between the second separator and a plurality of the unit cells,
A water supply 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;
An inlet connection channel that communicates the water supply communication hole and the water channel;
An outlet connecting flow path that connects the discharge communication hole and the water flow path;
And providing
The water electrolysis apparatus according to claim 1, wherein a channel cross-sectional area of the outlet connection channel is set larger than a channel cross-sectional area of the inlet connection channel. The water electrolysis device according to claim 1, wherein the inlet connection channel and the outlet connection channel have an opening cross-sectional circular shape,
A water electrolysis apparatus, wherein the outlet connection channel is set to have a larger number or a larger diameter than the inlet connection channel. The water electrolysis apparatus according to claim 1 or 2, wherein the unit cells are stacked in a vertical direction,
The water supply communication hole and the discharge communication hole allow the water to flow vertically upward.

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