JP2003226992A - Power feeding body for electrolytic cell, and electrolytic cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power feeding body by which electrolytic efficiency can be improved by lowering electrolytic voltage by the improvement of contactability with a solid polymer electrolyte film and also the durability of the film can be improved by effectively suppressing the damage of the film. <P>SOLUTION: The power feeding body has a first conductive porous body being in contact with the solid polymer electrolyte film; and a second conductive porous body provided onto the first conductive porous body on the opposite side to the film. The first conductive porous body has a central part facing the above second conductive porous body; and a peripheral extension part extending outward from the central part in a radial direction. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a feeder for an electrolytic cell for producing a desired gas such as hydrogen and / or oxygen using a solid polymer electrolyte membrane, and an electrolytic cell provided with the feeder.

[0002]

2. Description of the Related Art A gas generator using a solid polymer electrolyte membrane has been proposed and widely used because a desired gas of high purity can be obtained and there is no need to carry or store a cylinder or the like. Has been done. Hereinafter, a hydrogen / oxygen generating device that generates hydrogen and / or oxygen will be described as an example of the gas generating device.

The hydrogen / oxygen generator comprises a solid polymer electrolyte membrane having catalyst layers bonded on both sides, and a pair of an anode-side power supply member and a cathode disposed on both sides of the solid polymer electrolyte membrane. An electrolytic cell is provided which has a side power supply body and a pair of electrode plates arranged so as to sandwich the pair of power supply bodies, and these members are narrowed. Generally, the hydrogen / oxygen generator is used in a mode in which a plurality of the electrolytic cells are connected in series and end electrode plates are provided at both ends thereof.

By the way, the power supply in the electrolysis cell has liquid permeability for passing pure water or an electrolytic solution to the surface of the solid polymer electrolyte membrane, and electrolysis on the surface of the solid polymer electrolyte membrane. Are required to have conductivity, air permeability for releasing generated hydrogen and oxygen to the outside of the cell, and smoothness of the surface in contact with the solid polymer electrolyte membrane.

From this point of view, a power supply body made of a conductive porous body such as a metal mesh, a metal powder, or a metal fiber sintered body, which has low pores disposed on the side in contact with the solid polymer electrolyte membrane. Ratio of the first conductive porous body and a high porosity second conductive porous body disposed on the opposite side of the first conductive porous body from the solid polymer electrolyte membrane. A feeder having a multi-layer structure has been proposed.

FIG. 5 shows a vertical sectional view of an example of a conventional multi-structure type power feeding body. The power feeding body shown in FIG. 5 has a low porosity conductive porous body in contact with a solid polymer electrolyte membrane, and a hollow porosity conductive body disposed on the opposite side of the low void efficiency conductive porous body from the membrane. It is a three-layer type including a porous body and a high-porosity conductive porous body disposed on the side of the hollow porous conductive porous body opposite to the membrane. The conventional power supply body is effective in improving the smoothness of the membrane contact surface while maintaining conductivity and liquid permeability, but has the following disadvantages.

That is, as described above, the solid polymer electrolyte membrane is placed under a narrow pressure by a pair of power feeding members (anode-side power feeding member and cathode-side power feeding member). Since the solid polymer electrolyte membrane is very soft, if it is squeezed by the pair of power feeding bodies, the peripheral portions of the pair of power feeding bodies bite into the membrane, which may cause damage to the membrane.

In particular, in the case of a power supply body using a metal mesh, the end portion of the core material constituting the mesh is exposed at the peripheral edge, so that the solid polymer electrolyte membrane is likely to be damaged. There is.

Further, in the power feeding member made of a metal mesh, as shown in FIG. 6, in order to prevent the film from being damaged by the end portion of the core material, the periphery of the contact surface with the film is protected. Although it has been proposed to provide a ring, the problem that the peripheral portion of the protection ring bites into the solid polymer electrolyte membrane and damages the membrane still remains in this embodiment.

Since the protection ring 110 is generally integrated with a metal mesh power supply body, the protection ring 110 is made of the same material as the metal mesh.
That is, when the metal mesh power feeder is made of titanium, the protection ring 110 is also made of titanium and is integrated by welding or the like.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and improves the contactability with a solid polymer electrolyte membrane to lower the electrolysis voltage and improve the electrolysis efficiency. It is an object of the present invention to provide a power supply body that can be improved and effectively suppress damage to the film to improve the durability of the film.

[0012]

The present invention provides a power supply body used in an electrolysis cell for achieving the above object,
A first conductive porous body that is in contact with the solid polymer electrolyte membrane; and a second conductive porous body that is disposed on the opposite side of the first conductive porous body from the membrane. The conductive porous body provides a power supply body for an electrolytic cell, which has a central portion facing the second conductive porous body and a peripheral edge extending radially outward from the central portion. To do.

Preferably, the first conductive porous body is
The porosity may be lower than that of the second conductive porous body. Furthermore, preferably, the first and second conductive porous bodies can be integrated. In one aspect, the first and second conductive porous bodies may be titanium porous bodies. The titanium porous body may be made of titanium mesh or titanium etching. First
When the second conductive porous body is a titanium porous body, the first conductive porous body can be preferably plated with a platinum group metal such as platinum or gold.

In order to achieve the above object, the present invention provides a solid polymer electrolyte membrane and a power supply for an electrolytic cell according to any one of the above aspects, wherein the solid polymer electrolyte membrane is sandwiched between the solid polymer electrolyte membrane and the power supply body. A pair of anode-side power supply body and cathode-side power supply body provided, a pair of electrode plates arranged so as to sandwich the pair of power supply bodies, each of the solid polymer electrolyte membrane and the pair of electrode plates A pair of gaskets that cooperate to define an anode chamber and a cathode chamber, respectively, are provided on one side and the other side of the electrolyte membrane, and each of the pair of gaskets is a peripheral edge of the first conductive porous body. A large opening that has an opening diameter that surrounds the extending portion and that opens to the electrolyte membrane side, and an opening that extends from the large opening to the opposite side of the electrolyte membrane and that surrounds the second conductive porous body. A small opening whose diameter is reduced from the large opening along with a step to have a caliber Providing an electrolytic cell being a stepped shape having and. Preferably, the large opening of the gasket may have a depth equal to or greater than the thickness of the first conductive porous body of the power feeder.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a power supply for an electrolytic cell according to the present invention will be described below with reference to the accompanying drawings. 1 (a) and 1 (b) are a longitudinal side view and a plan view, respectively, of an electrolytic cell power feeder 1 according to the present embodiment, and FIG. 2 shows an example of an electrolytic cell in which the power feeder 1 is incorporated. It is a partial longitudinal cross-sectional view.

The power feeder 1 is a solid polymer electrolyte membrane 10
It is used as a component of an electrolysis cell that produces a desired gas such as hydrogen and / or oxygen using 0. Hereinafter, a case of generating hydrogen and / or oxygen will be described as an example. That is,
In the electrolytic cell, the anode-side power feeding body 1 and the cathode-side power feeding body 1 are disposed on one surface side and the other surface side of the solid polymer electrolyte membrane 100, respectively. The pair of feeders 1,
1 is a solid polymer electrolyte membrane 100 with each membrane contacting surface
It is fixed in a state of being pressed toward the film 100 so as to come into contact with one surface and the other surface. In such an electrolytic cell, a current is caused to flow between the pair of power feeders 1 and 1, and
By supplying pure water or an electrolytic solution to the contact portion of the power supply body 1 with the membrane 100, oxygen and hydrogen are generated in the anode chamber and the cathode chamber, respectively.

As described above, the power feeding body 1 is required to have conductivity, liquid permeability and air permeability, and is therefore formed of a conductive porous body. More specifically, FIG. 1 and FIG.
As shown in FIG.
A first conductive porous body 10 arranged on the side in contact with 00,
The first conductive porous body 10 has a laminated structure of a plurality of layers including the second conductive porous body 20 disposed on the opposite side of the membrane 100. In addition, in the present embodiment, the film 1 in the second conductive porous body 20.
The third conductive type porous body 30 is provided on the side opposite to 00 to form a three-layer type.

The first conductive porous body 10 in contact with the solid polymer electrolyte membrane 100 is the second conductive porous body 20.
It has a central portion 11 that comes into contact with the central portion 11, and a peripheral edge extending portion 12 that extends radially outward from the central portion 11. That is, the first conductive porous body 10 is the same as the second conductive porous body 20.
In addition to the central portion 11 corresponding to, a peripheral edge extending portion 12 surrounding the central portion 11 is provided.

As described above, the power feeding body 1 has a laminated structure composed of a plurality of conductive porous bodies, and the solid polymer electrolyte membrane 10 among the plurality of conductive porous bodies 10, 20 ,.
By setting the diameter of the first conductive porous body 10 in contact with 0 to be larger than that of the second conductive porous body 20 arranged on the opposite side of the first conductive porous body 10 from the film, The following effects can be obtained.

As described above, the pair of power feeding members 1 and 1 disposed with the solid polymer electrolyte membrane 100 sandwiched therebetween are the membrane 1
It is fixed while being pressed toward 00. That is, the power feeding body 1 is fixedly supported while being pressed by the entire area of the surface (the third porous power feeding body 30 in the present embodiment) separated from the membrane 100.

Here, when the pressing force is applied, the first
Considering the movement of the conductive porous body 10, the first conductive porous body 10 is, in addition to the central portion 11 corresponding to the second and third conductive porous bodies 20 and 30, as described above. The peripheral edge extending portion 12 extends radially outward from the central portion 11. The pressing force acts on the central portion 11, but does not act on the peripheral edge extending portion 12. Therefore, as shown in FIG. 2, the peripheral edge extending portion 12 receives a reaction force from the solid polymer electrolyte membrane 100, and the peripheral edge extends.
Bends away from 0.

As described above, the power feeding body 1 according to the present embodiment
In, the peripheral edge portion 12 of the first conductive porous body 10 in contact with the solid polymer electrolyte membrane 100 is curved in a direction away from the membrane 100. Therefore, it is possible to effectively prevent the periphery of the power feeding body from being bitten into the solid polymer electrolyte membrane as described in the section of the prior art, and thereby to prevent the membrane from being damaged.

Further, in the power feeding body 1, the central portion 11 of the first conductive porous body 10 is entirely covered by the pressing force applied through the second and third conductive porous bodies 20, 30. The membrane 100 can be surely brought into contact with the membrane 100, whereby the effective contact area of the power feeding body 1 with the membrane 100 can be increased and the electrolysis efficiency can be improved.

That is, in the conventional power feeding body 1 ″ (see FIG. 6) having the protection ring 110, the protection ring 110 is
The effective contact area with the film 100 is smaller than the areas of the second and third conductive power feeders 20 and 30 due to the step difference caused by. On the other hand, in the present embodiment, the second
Also, the entire area of the central portion 11 having the same area as the third conductive porous body 20, 30 can be reliably brought into contact with the solid polymer electrolyte membrane 100. Therefore, the protection ring 110
The effective contact area with the membrane 100 can be increased, and the electrolysis efficiency can be improved, as compared with the conventional power supply body 1 ″ provided with.

Preferably, the first conductive porous body 10
Can be made to have a low air efficiency as compared with the other conductor porous bodies 20 and 30, and thereby contact with the solid polymer electrolyte membrane 100 while maintaining liquid permeability, air permeability and conductivity. The smoothness of the surface can be improved.

The first to third conductive porous bodies 10, 20, 30 constituting the power feeding body 1 are mesh bodies made of a conductive material, sintered bodies made of particles or fibers of a conductive material, and the like. Various forms can be adopted. As the conductive substance,
When the power feeding body 1 is used on the anode side, titanium, niobium, titanium-palladium alloy and the like are exemplified from the viewpoint of being acid resistant and less elution of metal, but they are inexpensive and suitable for commercial use. Titanium is preferably used from the viewpoint that it is present. The solid polymer electrolyte membrane 100 is preferably used.
The first conductive porous body 10 that comes into contact with can be plated with a platinum group metal such as platinum or gold, whereby the oxidation resistance and hydrogen embrittlement resistance can be improved, and the contact can be improved. The resistance can be improved. When the power supply body 1 is used on the cathode side, examples of the conductive substance include stainless steel, graphite, and carbon.

Preferably, the first conductive porous body 10
Is configured such that when the power feeding body 1 is pressed toward the solid polymer electrolyte membrane 100, the peripheral edge extending portion can bend with respect to the main body portion. Specifically, the first conductive porous body 1
Physical properties of the material forming 0 (the radial length of the peripheral extension 12, the thickness of the first conductive porous body 10, the elastic coefficient of the first conductive porous body 10, etc.) and the solid polymer electrolyte Membrane 10
It is set according to the magnitude of the reaction force received from 0.

More preferably, the respective conductive porous bodies 10, 20, 30 constituting the power feeding body 1 can be integrated with each other, thereby reducing the electric resistance between the respective conductive porous bodies and the electrolytic cell. The assembling efficiency at the time of assembling can be improved. In particular, when the power feeding body 1 is formed of a metal mesh, the respective conductive porous bodies can be integrated by spot welding, which allows the flexibility of the first conductive porous body 10. Can be further improved.

In the present embodiment, the power feeding body 1 having a three-layer structure composed of the first to third conductive porous bodies 10, 20, 30 has been described as an example, but the present invention is in such a form. It is not limited. That is, as long as the conductive porous body has at least two layers of conductive porous bodies and the conductive porous body on the side in contact with the solid polymer electrolyte membrane 100 has a larger diameter than other conductive porous bodies, various forms are possible. Is applicable to.

A step gasket is preferably used in the electrolytic cell in which the power feeder according to the present embodiment is incorporated. FIG. 3 shows a vertical cross-sectional view of a main part of another example of the electrolytic cell including the power feeder according to the present embodiment.

The electrolytic cell shown in FIG. 3 is arranged so that the solid polymer electrolyte membrane 100, a pair of power feeding members 1 arranged with the electrolyte membrane 100 interposed therebetween, and the pair of power feeding members 1 sandwiched therebetween. The pair of electrode plates 50 and the electrolyte membrane 100 are sandwiched between them, and the anode chamber and the cathode are provided on one surface and the other surface of the electrolyte membrane in cooperation with each of the pair of electrode plates 50. And a pair of gaskets 40 defining a chamber.

The pair of gaskets 40 are respectively
The electrolyte membrane 100 has an opening diameter that surrounds the peripheral extension 12 of the first conductive porous body 10 in the power feeding body 1.
A large opening portion 41 that opens in the direction of, and an opening diameter that extends from the large opening portion 41 to the side opposite to the electrolyte membrane 100 and that surrounds the second and third conductive porous bodies 20 and 30. It has a stepped shape having a large opening 41 and a small opening 43 reduced in diameter along with a step 42.

More specifically, the depth of the large opening 41 in the gasket 40 is determined by the depth of the first conductive porous body 10.
Of the first conductive porous body 10 or larger than the thickness of the first conductive porous body 10. By providing the stepped gasket having such a configuration, while securely holding the power feeding body 1,
The central portion 11 of the first conductive porous body 10 is appropriately pressed against the solid polymer electrolyte membrane 100, and the peripheral edge extending portion 12 is effectively prevented from damaging the solid polymer electrolyte membrane 100. it can. Furthermore, in such a configuration,
The posture of the pair of step gaskets 40 with respect to the solid polymer electrolyte membrane 100 can be stabilized. That is, the contact between the pair of stepped gaskets 40 and the solid polymer electrolyte membrane 100 can be improved. Therefore, the contact property between the gasket on the anode chamber side / the solid polymer electrolyte membrane / the gasket on the cathode chamber side can be improved,
Thereby, the hermeticity of the anode chamber and the cathode chamber can be improved. Therefore, a desired sealing property can be obtained without excessive tightening when assembling the electrolytic cell.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the power supply body according to the present invention will be described below. In the present embodiment, as shown in FIGS. 1 to 3, a feeder having a three-layer structure made of titanium mesh, and a feeder obtained by spot welding each layer was adopted. In the present example, as the first conductive porous body,
The plate thickness is 0.1 mm, the diameter is 86 mm, and the mesh opening has a long opening width and a short opening width of 1.5 mm and 0.8, respectively.
A titanium mesh of mm was used. Further, as the second and third conductive porous bodies, a plate thickness of 0.2 mm, a diameter of 80 mm,
The long and short openings of the mesh opening are 5 each
mm and 2.4 mm titanium mesh was used.

As a comparative example, the same titanium mesh was used, and a conventional power supply body (see FIG. 6) having a titanium protective ring on the periphery of the first conductive porous body was used. That is, in the comparative example, the diameter of the first conductive porous body was 8
The structure is the same as that of the above-mentioned embodiment except that the thickness is 0 mm and the protective ring is provided.

The relationship of "cell voltage / current density" in the electrolytic cells using this example and the comparative example was measured. In addition,
The other conditions such as the pressure when pressing the power feeder against the solid polymer electrolyte membrane, the amount of pure water supplied, and the temperature were the same.

The measurement results are shown in FIG. As is apparent from FIG. 4, when the same current density was applied, it was sufficient in this example to apply a cell voltage smaller than that in the comparative example. This is considered to be due to the following reasons. That is, it is considered that the cell voltage of this example was smaller than that of the comparative example because the contact area between the first conductive porous body and the solid polymer electrolyte membrane was large. Conversely, in this example, it can be said that the same current density can be flowed with a small cell voltage, and therefore the electrolysis efficiency is improved.

[0038]

As described above, according to the power feeding body of the present invention, at least the first and second conductive porous bodies are provided,
Also, the first is disposed on the side in contact with the solid polymer electrolyte membrane
Since the conductive porous body has a larger diameter than the second conductive porous body, the effective contact area with the membrane can be expanded while effectively suppressing damage to the solid polymer electrolyte membrane by the periphery of the power feeding body. . Therefore, the durability of the solid polymer electrolyte membrane can be improved while improving the electrolysis efficiency of the electrolysis cell.
Further, in the electrolytic cell provided with the power supply according to the present invention, if the step gasket is used, the power supply is held securely,
The above effect can be effectively obtained.

[Brief description of drawings]

1A and 1B are a vertical sectional view and a plan view, respectively, of an embodiment of a power feeding body according to the present invention.

2 is a longitudinal sectional view of an essential part of an example of an electrolytic cell in which the power feeder shown in FIG. 1 is incorporated.

FIG. 3 is a longitudinal sectional view of a main part of another example of the electrolytic cell in which the power feeding body shown in FIG. 1 is incorporated.

FIG. 4 is a graph showing a relationship of “cell voltage / current density” between an example according to the present invention and a comparative example.

FIG. 5 is a vertical cross-sectional view of an example of a conventional power supply body.

FIG. 6 is a vertical cross-sectional view of another example of the conventional power feeding body.

[Explanation of symbols]

1 power supply 10 First conductive porous body 11 Central part 12 Peripheral extension 20 Second conductive porous body 40 gasket 50 electrode plate 100 solid polymer electrolyte membrane

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Koichi Wada             2-112 Jiyugaoka Honcho, Miki City, Hyogo Prefecture F-term (reference) 4K011 AA06 AA10 AA11 AA21 AA30                       CA04 DA01

Claims (7)

[Claims] 1. A power feeder used in an electrolysis cell, comprising a first conductive porous body in contact with a solid polymer electrolyte membrane, and a first conductive porous body disposed on the opposite side of the membrane. A second conductive porous body provided, wherein the first conductive porous body has a central portion facing the second conductive porous body, and extends radially outward from the central portion. An electrolytic cell power supply having a periphery extending portion. 2. The power supply body for an electrolytic cell according to claim 1, wherein the first conductive porous body has a porosity lower than that of the second conductive porous body. 3. The power feeder for an electrolytic cell according to claim 1, wherein the first and second conductive porous bodies are integrated. 4. The power feeder for an electrolytic cell according to claim 1, wherein the first and second conductive porous bodies are titanium porous bodies. 5. The power feeder for an electrolytic cell according to claim 4, wherein the first conductive porous body is plated with a platinum group metal. 6. A solid polymer electrolyte membrane, and the power feeder for an electrolytic cell according to claim 1, wherein the pair of anode-side power feeds are arranged so as to sandwich the solid polymer electrolyte membrane. Body and cathode-side power feeding body, a pair of electrode plates arranged so as to sandwich the pair of power feeding bodies, the solid polymer electrolyte membrane and the pair of electrode plates, respectively, and the electrolyte membrane On one side and on the other side, a pair of gaskets that respectively define an anode chamber and a cathode chamber are provided, and each of the pair of gaskets has an opening diameter that surrounds the peripheral extension of the first conductive porous body. A large opening opening to the electrolyte membrane side, and the large opening extending from the large opening to the side opposite to the electrolyte membrane and having an opening diameter surrounding the second conductive porous body. Has a stepped shape that has a small opening that is reduced in diameter along with the stepped portion. Electrolysis cell, characterized in that. 7. The electrolytic cell according to claim 6, wherein the large opening portion of the gasket has a depth equal to or greater than the thickness of the first conductive porous body of the power feeding body.