JP5364056B2 - Water electrolysis equipment - Google Patents

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.

  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.

  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 high-pressure hydrogen production apparatus disclosed in Patent Document 1 is known. As shown in FIG. 7, the high-pressure hydrogen production apparatus includes a plurality of unit cells 1 that are stacked. The single cell 1 includes a solid polymer electrolyte membrane 2, power feeders 3a and 3b, separators 4a and 4b, and fluid passages 5a and 5b provided in the separators 4a and 4b. While water is supplied to the fluid passage 5b, a high pressure hydrogen gas is obtained by electrolyzing the water by providing a back pressure valve on the discharge side of the hydrogen gas in the fluid passage 5a.

  The high-pressure hydrogen production apparatus includes a hydrogen gas guide path 6 that extends in the stacking direction of the single cells 1 and distributes high-pressure hydrogen gas. The cathode side separator 4 a is provided with an O-ring 7 around the hydrogen gas guide path 6.

JP 2006-316288 A

  By the way, in the high-pressure hydrogen production apparatus described above, the solid polymer electrolyte membrane 2 is likely to be exposed to the outside air at the portion outside the hydrogen gas guide path 6. For this reason, the solid polymer electrolyte membrane 2 is likely to be in a dry state at the outer portion compared to the inner portion circulated around the O-ring 7 or the like, and the solid polymer electrolyte membrane 2 has a dry portion and a wet portion. It will be mixed.

  Here, when the pressure of the generated hydrogen changes, the film thickness of the wet part at a low pressure is larger than the film thickness of the dry part at a low pressure. Accordingly, there is a problem that a gap is generated between the solid polymer electrolyte membrane 2 and the cathode-side separator 4a particularly at a low pressure, and the O-ring 7 protrudes into the gap and is damaged.

  The present invention solves this type of problem, and with a simple configuration, the electrolyte membrane does not partially dry, and reliably prevents damage to the seal member due to variations in the thickness of the electrolyte membrane. An object of the present invention is to provide a water electrolysis apparatus capable of performing the above.

  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.

  In this water electrolysis apparatus, a hydrogen discharge communication hole that extends in the stacking direction of the unit cells and communicates with the hydrogen flow path and discharges hydrogen in the stacking direction is provided, and one separator has the hydrogen discharge communication hole. And a water passage portion that circulates the one seal member and circulates the water, and the other separator has the other seal member that circulates the hydrogen discharge communication hole. Is provided.

  Moreover, in this water electrolysis apparatus, it is preferable that the other sealing member is arranged offset with respect to the one sealing member in the stacking direction.

  Furthermore, in this water electrolysis apparatus, it is preferable that the water passage portion is branched from the water flow path.

  Furthermore, in this water electrolysis apparatus, it is preferable that the hydrogen obtained in the hydrogen channel is set at a higher pressure than the water supplied to the water channel.

  According to the present invention, the one separator is provided with the water passage portion that circulates around the outside of the one sealing member to circulate the water, and prevents the outer portion of the one sealing member from drying. be able to. For this reason, it becomes possible to maintain the whole electrolyte membrane in a moist state, and when the surface pressure fluctuates, the film thickness of the electrolyte membrane does not partially differ even at a particularly low pressure.

  Accordingly, the electrolyte membrane is not partially dried with a simple configuration, and it is possible to reliably prevent damage to the seal member due to fluctuations in the thickness of the electrolyte membrane.

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 an explanatory view of the relationship between the film thickness of the dry part and the film thickness of the wet part of the solid polymer electrolyte membrane with respect to the surface pressure. 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 embodiment of this invention comprises the high pressure hydrogen production apparatus of about 10 Mpa-70 Mpa, and the several unit cell 12 is the perpendicular direction (arrow A direction). ) Are stacked.

  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.

  As shown in FIGS. 2 to 4, the unit cell 12 includes a substantially disk-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 outer periphery of the first protrusion 44a, the second protrusion 44b, and the third protrusion 44c is formed by three sides. The outer periphery may be formed in a semicircular shape. The first projecting portion 44a is provided with a water supply communication hole 46 having an oval opening cross section 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 having an oval opening cross section for discharging oxygen generated by the reaction and used water in communication with each other in the arrow A direction. The third protrusion 44c is provided with a hydrogen discharge communication hole 50 having a circular opening cross section for allowing hydrogen generated by the reaction to flow in the direction of arrow A, which is the stacking direction.

  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.

  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.

  A water passage portion 60 is formed by branching from the water flow path 54. Specifically, the water passage portion 60 communicates with the end portion of the arc-shaped inlet buffer portion 58a and the end portion of the arc-shaped outlet buffer portion 58b, and the water passage 60a that circulates outside the hydrogen discharge communication hole 50. Have. The water passage 60 a is closed at the inner side of the hydrogen discharge communication hole 50 so that both ends of the water connection passage 60 b communicate with each other, and the water passage portion 60 circulates the entire circumference of the hydrogen discharge communication hole 50. The water connection path 60b may be provided as necessary, and may be omitted.

  As shown in FIGS. 3 and 4, the cathode separator 36 is provided with a discharge passage 62 that communicates with the hydrogen discharge 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 go around the outside of the water supply communication hole 46, the discharge communication hole 48, and the hydrogen discharge communication hole 50 on the surface 36a of the cathode side separator 36. It is formed. 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, the first seal groove 76a circulates outside the water flow path 54 and faces the first seal groove 68a (the side facing the front). Is formed.

  The surface 34a circulates outside the water supply communication hole 46, the discharge communication hole 48, and the hydrogen discharge communication hole 50, and faces the second seal groove 68b, the third seal groove 68c, and the fourth seal groove 68d. A second 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. 3 to 5, the anode-side separator 34, which is one separator, includes a fourth seal member 78 d that is one seal member that circulates around the hydrogen discharge communication hole 50 and the fourth seal member 78 d. A water passage portion 60 that circulates and distributes water is provided. The cathode-side separator 36 that is the other separator is provided with a fourth seal member 70d that is the other seal member that goes around the hydrogen discharge communication hole 50.

  The fourth seal member 78d and the fourth seal member 70d are offset from each other in the stacking direction, and the water passage portion 60 is offset from the fourth seal member 70d in the stacking direction (see FIG. 4).

  As shown in FIGS. 1 and 2, a pipe 82a communicating with the water supply communication hole 46 is connected to the end plate 20b, and the end plate 20a communicates with the discharge communication hole 48 and the hydrogen discharge communication hole 50. Pipes 82b and 82c to be connected are connected. Although not shown, the pipe 82 c is provided with a back pressure valve (or electromagnetic valve), and the pressure of hydrogen generated in the hydrogen discharge communication hole 50 is set to be higher than the pressure of water supplied to the water supply communication hole 46. High pressure can be maintained.

  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. The hydrogen is maintained at a pressure higher than that of the water supply communication hole 46, and can flow out through the hydrogen discharge communication hole 50 in the vertical upward direction and be taken out of the water electrolysis apparatus 10. 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, the 3rd protrusion part 44c provided with the hydrogen discharge | emission communication hole 50 protrudes outward from the outer peripheral part of the unit cell 12, and 3 sides are exposed to external air. Accordingly, in the third protrusion 44 c of the solid polymer electrolyte membrane 38, the outer part of the hydrogen discharge communication hole 50 is in a dry state as compared with the inner part of the hydrogen discharge communication hole 50. As a result, the dry portion and the wet portion are mixed in the solid polymer electrolyte membrane 38.

  At that time, as shown in FIG. 6, the solid polymer electrolyte membrane 38 has a changed state in which the thickness of the dry portion and the thickness of the wet portion are different from each other with respect to variations in the surface pressure. That is, when the pressure is high (when performing high pressure hydrogen generation water electrolysis), the thickness of the drying part and the wet part is almost the same or the thickness of the drying part is thicker, while the thickness of the drying part is high (water electrolysis is performed). When it is stopped), the film thickness of the wet part is larger than the film thickness of the dry part.

  Here, in this embodiment, as shown in FIGS. 3 to 5, the anode-side separator 34 has a fourth seal member 78 d that circulates the hydrogen discharge communication hole 50 and a fourth seal member 78 d that circulates. A water passage portion 60 through which water is circulated is provided. On the other hand, the cathode-side separator 36 is provided with a fourth seal member 70d that goes around the hydrogen discharge communication hole 50.

  For this reason, water is introduced into the water passage portion 60 branched from the water flow path 54. As this water flows through the water passage 60a and the water connection passage 60b, the solid polymer electrolyte membrane 38 is humidified in the outer portion of the fourth seal member 78d that circulates the hydrogen discharge communication hole 50, and the outer portion is dried. Can be prevented well.

  Accordingly, it becomes possible to maintain the entire solid polymer electrolyte membrane 38 in a wet state, and when the surface pressure fluctuates, the film thickness of the solid polymer electrolyte membrane 38 is partially increased even at a low pressure. There is no difference.

  Thereby, with a simple configuration, the solid polymer electrolyte membrane 38 is not partially dried, and fluctuations in the film thickness of the solid polymer electrolyte membrane 38 can be prevented, and the fourth seal member 70d protrudes. The effect that it becomes possible to prevent the damage by this reliably 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 feeders 44a-44c ... Projection 46 ... Water supply communication hole 48 ... Discharge communication hole 50 ... Hydrogen discharge communication hole 52a ... Inlet connection flow path 52b ... 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 paths 68a-68d, 76a-76d ... Seal grooves 70a to 70d, 78a to 78d ... Seal members

Claims (4)

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 hydrogen discharge communication hole extending in the stacking direction of the unit cells and communicating with the hydrogen flow path to discharge the hydrogen in the stacking direction is provided.
The one separator has one seal member that circulates around the hydrogen discharge communication hole;
A water passage portion that circulates around the one sealing member and distributes the water;
Is provided,
The water separator is characterized in that the other separator is provided with the other seal member that goes around the hydrogen discharge communication hole.   2. The water electrolysis apparatus according to claim 1, wherein the other sealing member is arranged to be offset from each other in the stacking direction with respect to the one sealing member.   3. The water electrolysis apparatus according to claim 1, wherein the water passage portion is formed by branching from the water flow path.   The water electrolysis apparatus according to any one of claims 1 to 3, wherein the hydrogen obtained in the hydrogen flow path is set to a pressure higher than that of the water supplied to the water flow path. Water electrolyzer.

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