JP2005097746A - Hydrogen-feeding device using solid polymer type water electrolysis tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen-feeding device using a solid polymer type water electrolysis tank, which prevents the damage to an electrolyte film even when water is electrolyzed in a high pressure of about several tens MPa, moreover has sufficient pressure resistance, and simplifies/miniaturizes the structure of a pressure vessel. <P>SOLUTION: This hydrogen-feeding device has a pressure vessel 41 provided with a lid 42, for storing the water electrolysis tank 40. An electrolysis-tank-pressing foot 42a for pressing the water electrolysis tank 40 to a bottom wall of a main body of the pressure vessel 41 is installed between the water electrolysis tank 40 and the lid 42. A gap is formed between the water electrolysis tank 40 and the lid 42, which works as a section 43 for separating hydrogen gas from the liquid. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a water electrolyzer that electrolyzes water using a solid polymer electrolyte membrane and generates oxygen at an anode and hydrogen at a cathode, and more specifically, high-pressure hydrogen gas of 35 to 70 MPa, for example, at a hydrogen station for a fuel cell. The present invention relates to a hydrogen supply apparatus capable of supplying

  A hydrogen supply apparatus using a solid polymer type water electrolyzer is conventionally known as disclosed in, for example, Patent Document 1, and the water electrolyzer (51) is shown in FIGS. 7, the anode main electrode (1) and the cathode main electrode (2) arranged at both ends, and a plurality of unit cells (16) arranged in series between these main electrodes (1) and (2) ) And a pair of end plates (13) sandwiching a combination of an anode main electrode (1) -a plurality of unit cells (16) -cathode main electrode (2) from both sides. One cell (16) consists of the anode side of the bipolar plate (90), the anode feeder (7), the electrode assembly film (3), the cathode feeder (8), and the adjacent bipolar plate (90). The electrode assembly membrane (3) is mainly configured from the cathode side, and includes an ion exchange membrane (4) and catalyst electrode layers (5) and (6) provided on both surfaces thereof. At the periphery of each cell (16) is an O-ring that seals the inside and outside of the water electrolysis cell between the electrode assembly membrane (3) and the surface of the bipolar plate (90) on the cathode feeder (8) side. (17) is interposed. In the water electrolysis tank (51), a water supply header (10) is formed at the center of the lower end portion, and a hydrogen header (11) and an oxygen header (12) are formed in parallel with the upper end portion.

In this hydrogen supply device, heat is generated by the electrolytic reaction of the water electrolysis tank (51), and the exhaust heat is generated by movement by circulating water on the oxygen side and latent heat of vaporization of water vapor on the hydrogen side. In this apparatus, the internal pressure is maintained by an O-ring (17) provided on the outer periphery of the water electrolysis tank (51), and the pressure of the generated gas is 1.1 MPa (10 kg / cm ² G). It is said that it is less than.

Further, Patent Document 2 discloses that a water electrolyzer is installed in a pressure vessel.
JP-A-11-256380 JP-A-6-33283

  By the way, the use of hydrogen in fuel cells is progressing, and for that purpose, it is a problem to supply high-pressure hydrogen gas of 35 to 70 MPa at a hydrogen station for fuel cells.

  However, when water electrolysis is performed at a high pressure of about several tens of MPa using the above-described conventional hydrogen supply apparatus, there is a problem that the seal by the O-ring is broken. Therefore, as shown in Patent Document 2, it is conceivable to install the water electrolyzer in the pressure vessel. However, the point that can handle a high pressure of about several tens of MPa and the structure of the pressure vessel are as simple and small in capacity as possible. Satisfactory things have not been obtained in terms of making things.

  In the present invention, even when water electrolysis is performed at a high pressure of about several tens of MPa, the electrolyte membrane is prevented from being damaged, and has sufficient pressure resistance performance, and the pressure vessel structure is as simple and small in capacity as possible. It is an object of the present invention to provide a hydrogen supply apparatus using a solid polymer type water electrolyzer that can be used.

  A hydrogen supply apparatus using a solid polymer type water electrolyzer according to the present invention comprises a polymer electrolyte membrane for electrolyzing water to generate oxygen at the anode and hydrogen at the cathode, A hydrogen supply device comprising a pressure vessel with a lid for containing a water electrolyzer, wherein an electrolyzer holder for pressing the water electrolyzer against the bottom wall of the pressure vessel body is provided between the water electrolyzer and the lid, A gap serving as a hydrogen gas-liquid separator is formed between the tank and the lid.

  A pressure vessel is formed by covering a cylindrical vessel body whose upper end is opened, and a water electrolysis tank is composed of, for example, a bipolar plate, an anode feeder, an electrode assembly film, and a cathode feeder constituting the vessel. However, the horizontal parallel passages, which are the passages for the electrolyzed water and oxygen of each cell, are provided on either the front or back of each bipolar plate, and the hydrogen gas passages for each cell are provided on the other side. A horizontal parallel passage is formed, and the hydrogen gas passage of each cell is joined to a hydrogen header extending vertically through each bipolar plate. Electrolyzed water is forced through the electrolyzed water passage in the water electrolyzer by a pump or the like, thereby generating oxygen at the anode and hydrogen at the cathode. Since the generated hydrogen moves upward in the water electrolysis tank and is stored at the top of the pressure vessel, hydrogen can be obtained by providing a hydrogen gas-liquid separator at the top of the pressure vessel.

  In the electrolyzed water passage in the water electrolyzer, the entire electrolyzer is made up by the electrolyzed water as compared with the case where the electrolyzed water is supplied by a single feed header. Since the water can be cooled almost uniformly and the flow rate of the electrolyzed water can be increased, the electrolytic cell is efficiently cooled, and therefore, the temperature of the electrolyte membrane is suppressed from being locally higher than the heat resistant temperature. Even when water electrolysis is performed at a high pressure of about several tens of MPa, the electrolyte membrane is prevented from being damaged.

  It is preferable that the water electrolyzer is formed by densely laminating a bipolar plate having an O-ring fitted on the outer periphery in the container body. In this way, when the O-ring extends in the radial direction is regulated by the inner peripheral surface of the pressure vessel, the O-ring does not break even when the internal pressure of the electrolytic cell becomes high, and high-pressure hydrogen gas is required. In this case, the pressure vessel can be made small and simple.

  Moreover, the pressure vessel is formed by covering a cylindrical vessel body whose upper end is open with an insulating layer interposed therebetween, and the vessel body and the lid are preferably electrodes. Since the pressure vessel and the electrode of the water electrolysis tank are in direct contact with each other, it is conceivable that the pressure vessel, usually made of metal, is formed of an insulating material and the electrode of the water electrolysis vessel is taken out of the pressure vessel. By making use of the fact that the container is made of metal and using the container body and the lid as electrodes, the structure for taking out the electrode of the water electrolysis tank to the outside of the pressure container can be omitted.

  According to the hydrogen supply apparatus using the solid polymer type water electrolyzer of the present invention, the structure in which the water electrolyzer is accommodated in the pressure vessel is adopted, and the electrolyzer holder that presses the water electrolyzer against the bottom wall of the pressure vessel body is water. By being provided between the electrolytic cell and the lid, the structure of the pressure vessel can be made as simple and small as possible, even when water electrolysis is performed at a high pressure of about several tens of MPa, It is possible to prevent damage to the electrolyte membrane and ensure sufficient pressure resistance. In addition, since a gap serving as a hydrogen gas / liquid separator is formed between the water electrolysis tank and the lid, the hydrogen gas / liquid separator can be omitted from the hydrogen supply device.

  Hereinafter, the present invention will be specifically described with reference to the drawings. In the following description, left and right and top and bottom refer to left and right and top and bottom in FIG. 1, and a direction orthogonal to these is referred to as front and back.

  In FIG. 1, a hydrogen supply apparatus using a solid polymer type water electrolyzer uses a polymer electrolyte membrane to electrolyze water, and generates oxygen at the anode and hydrogen at the cathode, respectively. (40), a pressure vessel (41) with a lid (42) for housing the water electrolyzer (40), a hydrogen gas / liquid separation unit (43) provided on the top of the pressure vessel (41), and a hydrogen gas / liquid A hydrogen line (44) provided in the separation part (43), an oxygen line (45) connected to the water / oxygen discharge port on the peripheral wall of the pressure vessel (41), and an oxygen line (45) provided with water An oxygen gas-liquid separator (46) for separating oxygen and water generated at the anode of the electrolytic cell (40), and a circulation pump (48), an oxygen gas-liquid separator (46) and a pressure vessel (41) A water circulation line (47) for connecting to the water inlet and a DC power source (not shown) connected to the water electrolysis tank (40).

  As shown in FIG. 3, each cell (16) of the water electrolysis tank (40) has an anode side of the bipolar plate (19), an anode feeder (7), an electrode assembly film (3), a cathode feeder ( 8) and the cathode side of the adjacent bipolar plate (19). The electrode assembly membrane (3) includes an ion exchange membrane (4) and catalyst electrode layers (5) and (6) provided on both sides thereof.

  The bipolar plate (19) is obtained by grinding a thick plate. As shown in FIG. 2 (a) and FIG. 4, the bipolar plate (19) has a disk shape, and parallel passages (19a, 19b) are formed on both sides thereof. In addition, an O-ring (50) is fitted in an annular groove provided on the outer periphery. In FIG. 4, the passage provided on the upper surface of the bipolar plate is the passage (19a) on the oxygen generation side, and the passage provided on the lower surface is the passage (19b) on the hydrogen generation side. The hydrogen generation side passage (19b) does not open to the outer periphery of the bipolar plate (19) as shown in FIG. 5C, whereas the oxygen generation side passage (19a) As shown in FIGS. 5A and 5B, an open communication passage (19c) that opens to the outer periphery of the bipolar plate (19) and that serves as an inlet for water and an outlet for water and oxygen is communicated. . The open communication path (19c) does not open on the upper and lower surfaces of the bipolar plate (19), but opens only on the outer periphery.

  The bipolar plate (19) with the O-ring (50) is horizontally layered so that the passages (19a) and (19b) are oriented horizontally and the O-ring (50) is in contact with the inner periphery of the pressure vessel (41). Are stacked. A water electrolysis tank (40) formed by laminating a bipolar plate (19), an anode feeder (7), an electrode assembly film (3) and a cathode feeder (8) penetrates this vertically. A hydrogen header (49) is formed in the direction.

  As shown in FIG. 5, the hydrogen header (49) has a vertical through-hole (49a) that penetrates the bipolar plate (19), the anode feeder (7), the electrode assembly film (3), and the cathode feeder (8). ) And a pair of passage forming rings (55) (55) (55) (58) fitted into stepped holes (57) (58) provided in each bipolar plate (19) via O-rings (53) (54). 56). Each of the passage forming rings (55) and (56) is made of ceramic or heat-resistant resin (for example, engineering plastic), and has a small diameter portion having the same inner diameter and a smaller outer diameter at one end. One O-ring (53) is fitted into the outer periphery of the small-diameter portion, and the other O-ring (54) is fitted into the annular groove on the end surface without the small-diameter portion so as not to be exposed to the passage. The end surfaces of the large-diameter portions of the forming rings (55) and (56) are abutted with each other, and the end surfaces of the small-diameter portions are brought into contact with the portion having the smallest inner diameter of the bipolar plate. The hydrogen side passage forming ring (56) is provided with a plurality of small holes (56a) of about 1 to 2 mm on the side surface.

  Thus, in the water electrolysis tank (40), horizontal parallel passages (19a) (19c) that serve as electrolytic water and oxygen passages for each cell, and horizontal parallel passages (19b) that serve as hydrogen gas passages for each cell. And a vertical hydrogen header (49) in which these hydrogen gas passages are merged. The O-ring (50) fitted to the outer periphery of the bipolar plate (19) is suppressed from increasing in diameter by the inner periphery of the pressure vessel (41).

  The pressure vessel (41) is formed by covering a cylindrical vessel body whose upper end is open with a lid (42) through an insulating layer.In this embodiment, the vessel body is a cathode and a lid (42 ) Is the anode. A downwardly projecting electrolytic cell holder (42a) is provided on the lower surface of the lid (42) of the pressure vessel (41). This electrolytic cell holder (42a) presses the entire water electrolytic cell (40) against the bottom wall of the container body, and between the lid (42) of the pressure vessel (41) and the upper surface of the water electrolytic cell (40), A gap corresponding to the length of the electrolytic cell holder (42a) is formed. By adjusting the pressure of pure water supplied to the water electrolysis tank (40), an electrolyzed water layer is secured in this gap, and a layer of generated hydrogen gas is formed above the electrolyzed water layer, Thus, a hydrogen gas-liquid separation part (43) is formed at the top of the pressure vessel (41).

  According to the hydrogen supply device using the solid polymer type water electrolyzer of this embodiment, the electrolyzed water forcedly fed into the water electrolyzer (40) by the circulation pump (48) is supplied to the bipolar plate (19). It flows from the left to the right through the horizontal parallel passages (19a) and (19c), is decomposed into hydrogen and oxygen, functions as cooling water in the water electrolysis tank (40), and is discharged from the pressure vessel (41). Oxygen generated at the anode flows through the parallel parallel passages (19a) and (19c) of the bipolar plate (19) together with the electrolyzed water, and hydrogen generated at the cathode is horizontal parallel of the bipolar plates (19) of each cell. It flows through the passage (19b), joins the hydrogen header (49), and is stored at the top of the pressure vessel (41). The purity of the hydrogen gas is increased in the hydrogen gas-liquid separator (43) at the top of the pressure vessel (41), and is adjusted to a predetermined pressure by a check valve pressure valve (44a) provided in the hydrogen line (44). Supplied to the outside. A conventional bipolar plate is formed by corrugating thin plates into a corrugated shape, resulting in variations in contact between the ion exchange membrane (4) and the catalyst electrode layers (5) and (6) due to pressure deflection. However, by using the bipolar plate (19) obtained by grinding a thick plate, variation can be suppressed and hydrogen can be stably obtained.

  Exhaust heat of the water electrolysis tank (40) is performed by introducing cooled circulating water into the pressure vessel (41) and filling the gap with the water electrolysis tank (40). When water electrolysis is performed at high pressure, the amount of water vapor generated on the hydrogen side is drastically reduced. Compensated by heat. Thus, even when high-pressure hydrogen gas is generated, the electrode assembly membrane (electrolyte membrane) (3) is prevented from being damaged.

  In addition, since the conventional rubber bushing is not used to form the hydrogen header (49), the problem of poor processing accuracy and large thermal deformation due to the rubber bushing has been eliminated. .

  In the above description, the bipolar plate (19) has a disc shape. However, as shown in FIG. 2 (b), the bipolar plate (19) is a square plate shape with corners chamfered and rounded. It can also be used. The bipolar plate (19) is formed by grinding a thick aluminum plate to form passages (19a) and (19b). The surface is coated with titanium / platinum. The passages (19a) and (19b) may be curved or bent.

  By manufacturing the bipolar plate (19) with a manufacturing method that performs groove grinding on a thick plate, the peripheral edge of the bipolar plate (19) can be made thicker, the strength of the bipolar plate (19) is increased, and the high pressure Even when the gas is generated, the cell is not distorted and the pressure resistance is improved. Furthermore, the rigidity of the entire cell is increased by tightening, and a high-strength water electrolyzer is obtained.

It is the schematic which shows the hydrogen supply apparatus using the solid polymer electrolytic cell by this invention. It is a perspective view which shows an example of a bipolar plate, and its modification. It is a vertical longitudinal cross-sectional view which shows the principal part of a solid polymer type water electrolyzer. It is a figure which shows the detail of the channel | path shape of a bipolar plate, (a) is the front view seen from the advancing direction of water, (b) is a top view, (c) is a bottom view. It is sectional drawing which shows the detail of a hydrogen header. It is a disassembled perspective view which shows the conventional polymer-type water electrolyzer. It is a vertical sectional view showing a conventional polymer type water electrolyzer.

Explanation of symbols

(40): Solid polymer water electrolyzer
(41): Pressure vessel
(42): Lid
(42a): Electrolyzer holder
(43): Hydrogen gas-liquid separator
(49): Hydrogen header
(50): O-ring

Claims (3)

A hydrogen supply device comprising a solid polymer water electrolyzer that electrolyzes water using a polymer electrolyte membrane and generates oxygen at the anode and hydrogen at the cathode, and a pressure vessel with a lid for housing the water electrolyzer. And
An electrolytic cell holder that presses the water electrolytic cell against the bottom wall of the pressure vessel body is provided between the water electrolytic cell and the lid, and a gap is formed between the water electrolytic cell and the lid as a hydrogen gas-liquid separation unit. A hydrogen supply apparatus using a solid polymer electrolytic cell, characterized in that   2. The polymer electrolyte water electrolyzer according to claim 1, wherein a water electrolyzer is formed by densely laminating a bipolar plate having an O-ring fitted on the outer periphery thereof in the container body. Hydrogen supply device using   The solid container according to claim 1 or 2, wherein the pressure vessel is formed by covering a cylindrical vessel body having an open upper end with an insulating layer interposed between the lid and the vessel body and the lid as electrodes. A hydrogen supply device using a polymer water electrolyzer.

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