JP2001057217A - Polymer electrolyte type fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain high battery performance fairly independently to the humidification of supplied gas. SOLUTION: This fuel cell is provided with a polymer electrolyte membrane, a pair of electrodes with the polymer electrolyte membrane between them, an anode side separator having a gas passage for supplying fuel gas to one electrode, a cathode side separator having a gas passage for supplying oxidizer gas to the other electrode, catalyst layers 2 where the electrodes in contact with the polymer electrolyte membrane, electrode base materials 3 having gas permeability and electron conductivity, and water repellant layers 4 placed between the catalyst layers and the electrode base materials. The water repellant layers have multiple through-holes 5, and the catalyst layers and the electrode base materials are electrically connected through the through-holes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a portable power supply,
The present invention relates to a polymer electrolyte fuel cell used for a distributed power source, a cogeneration system, and the like, and particularly to an improvement in an electrode thereof.

[0002]

2. Description of the Related Art In general, a fuel cell is composed of an electrolyte, a pair of electrodes arranged on both sides of the electrolyte and having a gas diffusion function and a catalyst function, and an anode having a gas flow path for supplying a fuel such as hydrogen to one electrode. The unit cell includes a conductive separator and a cathode-side conductive separator having a gas flow path for supplying an oxidizing gas such as air to the other electrode. Then, by causing the fuel and the oxidant to react electrochemically, electricity and heat are simultaneously generated.
In a polymer electrolyte fuel cell using a polymer electrolyte membrane that conducts hydrogen ions as an electrolyte, a catalyst layer mainly composed of a carbon powder carrying a platinum group metal catalyst is adhered to both surfaces of the electrolyte membrane. Further, a pair of electrode base materials having both air permeability and conductivity are adhered to the outer surface of the catalyst layer. The electrode substrate and the catalyst layer are combined to form an electrode. As the electrode substrate, carbon paper having relatively high elasticity such as carded paper, flexible carbon cloth or carbon felt is usually used.

[0003] Outside the electrodes, a conductive separator plate for mechanically fixing a joined body (MEA) of the electrolyte membrane and the electrodes and electrically connecting adjacent MEAs in series with each other is arranged. Usually, a carbon plate is used as the separator plate. In a portion where the separator plate and the electrode are in contact, a gas flow path for supplying a reaction gas into the electrode and carrying away generated gas and surplus gas is formed. At the electrode (anode) on the hydrogen supply side, the hydrogen supplied from the gas flow path to the catalyst layer via the electrode base material is oxidized to hydrogen ions, and the hydrogen ions are supplied to the air supply side by the electrolyte membrane. To the electrode (cathode). At the cathode, hydrogen ions and oxygen react in the catalyst layer to generate water. The electrons generated at this time flow from the anode to the cathode through an external circuit. In order for the above reaction to proceed efficiently, it is necessary to supply a reaction gas to the reaction part of the catalyst layer and efficiently remove drain gas such as water vapor generated by the catalyst reaction, so that an appropriate airway must be secured in the electrode. No.

Conventionally, polytetrafluoroethylene (PT)
The above-mentioned airway was secured by using a fluorine-based polymer such as FE) as a water-repellent agent and mixing it with the electrode substrate and the catalyst layer. Specifically, the carbon paper constituting the electrode substrate is impregnated or coated with a colloidal dispersion of a fluoropolymer, the solvent is removed by drying, and heat treatment is performed at 350 to 450 ° C., so that the carbon paper has a fluorine content. The system polymer was fixed. Further, in order to impart water repellency to the catalyst layer, a fluorine-based polymer water repellent is fixed in advance to carbon powder different from the carbon powder carrying platinum, and this is combined with the carbon powder carrying platinum. The method of mixing uniformly was adopted. As the fluorine-based polymer, those having modified properties such as a glass transition point by modifying various substituents such as a perfluoromethyl group in addition to PTFE are used.

In recent years, a water-repellent treatment has been performed on the side of the electrode substrate having gas permeability and electronic conductivity that is in contact with the catalyst layer,
Applying hydrophilic treatment with SiO ₂ to other parts,
Attempts have been made to control the water repellency of the components of the electrode and to more effectively drain the generated water.
In the method in which the surface of a battery component having conductivity, such as carbon particles and carbon fibers, is subjected to a water-repellent treatment using a dispersion of a fluoropolymer such as PTFE, the entire surface of the battery component is coated with a fluoropolymer. Difficult to do. Therefore, when viewed microscopically, there is a portion that is not covered with the fluorine-based polymer, and this portion becomes wet with water over time, and the water repellency decreases as a whole. When the amount of the fluoropolymer is increased to enhance the water repellency, the electrical contact between carbon fibers and carbon particles is impaired, and the battery performance is reduced.

[0006] It has been pointed out that when a hydrophilic treatment such as SiO ₂ is applied to an electrode base material, battery performance, which is considered to be affected by the hydrophilic treatment, is lowered. When such a mere hydrophilic treatment is performed, the water retention of the electrode substrate is low, and the battery performance is greatly affected by the fluctuation of the humidity of the supplied gas. In a polymer electrolyte fuel cell, water is generated at an electrode during operation. The generated water is vaporized, mixed with the supply gas, and discharged as a drain gas. As a result, among the stacked unit cells, the humidity differs between the upstream side and the downstream side of the supply gas. This tendency becomes more pronounced as the gas utilization rate increases. In order to increase the efficiency of the battery, an electrode having a performance that is not so affected by the humidity of the supplied gas is required.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polymer electrolyte fuel cell capable of solving the above-mentioned disadvantages and maintaining high cell performance.

[0008]

The polymer electrolyte fuel cell of the present invention comprises a polymer electrolyte membrane, a pair of electrodes sandwiching the polymer electrolyte membrane, and a gas flow path for supplying a fuel gas to one of the electrodes. An anode having a cathode separator having a gas flow path for supplying an oxidizing gas to the other electrode and the other electrode, wherein the electrode is a catalyst layer in contact with the polymer electrolyte membrane, gas permeability and electron conductivity. And a water-repellent layer interposed between the catalyst layer and the electrode substrate, wherein the water-repellent layer has a large number of through-holes, through which the catalyst layer and the electrode It is characterized by being electrically connected to the base material. The through holes are distributed such that the average distance between the holes is smaller than the width of the gas passage of the separator. That is, it is preferable that the catalyst layer and the electrode substrate be electrically connected through the through holes in such a distribution state. Further, it is preferable that the electrode base material is made of carbon fiber subjected to a surface area increasing treatment.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 schematically shows a cross section of a main part of an MEA of a polymer electrolyte fuel cell according to the present invention. A water-repellent layer 4 having a through-hole 5 made of a water-repellent material is provided between the catalyst layer 2 formed in contact with the polymer electrolyte membrane 1 and the electrode substrate 3. This through hole extends from the electrode substrate side to the catalyst layer side. According to such a configuration, the supply of the reaction gas such as hydrogen and oxygen to the catalyst layer and the discharge of the water vapor generated by the catalytic reaction from the catalyst layer are performed by the water-repellent layer 4.
Through a hole 5 provided partially in the hole. When a water-repellent layer is made of a water-repellent material such as Teflon (registered trademark) sheet sold under the name of GORE-TEX, the gas can be passed through the micropores of the layer or to the same layer. The gas is exchanged between the catalyst layer and the electrode substrate by diffusion or dissolution. In addition, by providing a layer made of a water-repellent material between the catalyst layer and the electrode substrate, the water repellency of the electrode can be significantly increased as compared with the conventional method, and deterioration over time can be reduced. it can. As a result, the water generated in the catalyst layer is confined in the catalyst layer, so that even when a relatively low-humidity dry gas is supplied to the electrodes, the performance of the electrolyte membrane and the electrolyte in the catalyst layer is reduced by drying. Is suppressed. On the other hand, the generated water overflowing from the catalyst layer is
Of the holes provided in the water-repellent layer, the holes are extruded into the electrode base material by water pressure through relatively large holes, are vaporized into a supply gas, and are removed.

[0010] A preferred method of manufacturing the above-mentioned electrode having a water-repellent layer according to the present invention is a step of forming a water-repellent layer on one surface of an electrode substrate, and forming the water-repellent layer on the electrode substrate having the water-repellent layer formed thereon. And a step of applying a catalyst layer to the surface. The method for forming the water-repellent layer is described below. 1) The first method is to use a water-repellent fluororesin, especially PTFE
Is sprayed on one side of an electrode substrate heated to 95 to 100 ° C. by atomizing the aqueous dispersion. After forming the water-repellent layer, it is preferable to heat the water-repellent layer to an electrode substrate by heating to 250 to 380 ° C. 2) The second method is a method in which an organic solvent solution or slurry of pitch fluoride is applied to one surface of an electrode substrate and dried to form a water-repellent layer. 3) A method in which a thin sheet (up to a thickness of about 5 μm) of a water-repellent fluororesin, particularly PTFE, is attached to one surface of an electrode substrate by hot pressing. PTFE used here
Is preferably provided with a large number of holes having a diameter of 0.1 μm to 1.0 mm in advance.

The water-repellent layer of the electrode of the present invention has a thickness of 1 μm to
50 μm, and the total area of the through holes per unit area is 0.05 to 0.5 c.
It is preferable to have it on the order of m ² / cm ² . When a material whose contact angle with water is 90 degrees or less, that is, a hydrophilic material, is used as the electrode base material, the generated water extruded into the electrode base material quickly spreads in the electrode base material. Since the vaporization area increases, the vaporization of water is promoted. In a preferred embodiment of the present invention, the surface area of the electrode base material is increased by the activation treatment of the electrode base material or by the calcined decomposition product of the carbon particles or the organic binder, so that the vaporized area is further increased. At the same time, the effect of retaining the generated water also increases.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments. The present invention is not limited to these examples.

Example 1 A carbon powder having a particle diameter of several microns or less was impregnated with an aqueous solution of chloroplatinic acid and subjected to a reduction treatment, whereby a platinum catalyst was supported on the surface of the carbon powder. This is used as catalytic carbon powder. The weight ratio of carbon and supported platinum was approximately 2: 1. Next, the slurry obtained by mixing the carbon powder with the aqueous dispersion of polytetrafluoroethylene (PTFE) was forcibly stirred, dried, and then heat-treated. Thus, a water-repellent carbon powder in which PTFE was attached to the carbon powder was obtained. The catalyst carbon powder and the water-repellent carbon powder were uniformly mixed at a weight ratio of about 3: 1, and butyl acetate was added to the mixture and kneaded to obtain an ink for preparing a catalyst layer. Next, carbon paper (thickness: 50-80%, manufactured by Toray Co., Ltd.) having a thickness of 500 μm serving as an electrode substrate is heated from below by infrared irradiation, and its surface temperature is set to 95 ° C. to 1 ° C.
While maintaining the temperature at 00 ° C., an aqueous dispersion of atomized PTFE was dropped on the upper surface of the carbon paper by a spray device. In the atomized PTFE aqueous dispersion, moisture was evaporated on the surface of the carbon paper, and PTFE was deposited on the upper surface of the carbon paper to form a water-repellent material layer. Surface temperature of carbon paper is 110
When the temperature was higher than ℃, the solid component of PTFE did not adhere to the surface of the carbon paper, and when the temperature was lower than 80 ° C, the aqueous dispersion permeated the inside of the carbon paper, and the inside of the carbon paper was in a state of water repellency.

As described above, a water-repellent layer having a thickness of about 30 μm was formed on the carbon paper by adjusting the time for atomizing and depositing the aqueous PTFE dispersion on the carbon paper. When observing this water repellent layer with a microscope,
The water-repellent layer had unevenness in thickness and had holes in which carbon paper was partially exposed. Next, in order to improve the adhesion of the water-repellent layer to the carbon paper, the carbon paper on which the water-repellent layer was formed was heated in an atmosphere at 250 to 380 ° C for a short time. When the heating time was prolonged, the holes of the water-repellent layer where the carbon paper was exposed were closed, and in severe cases, softened PTFE penetrated into the carbon paper. In addition, the water-repellent layer itself became a dense continuous film, and gas permeability was lost.

The ink for preparing the catalyst layer was applied by a spray coating method to the side of the water-repellent layer of the carbon paper on which the water-repellent layer made of porous PTFE was formed on one side. Although the coating could be performed by using the screen printing method, the uniformity of the coated surface was higher by using the spray coating method. The coating amount of the catalyst layer is 0.5
mg / cm ² . As a material for forming the water repellent layer,
In addition to PTFE, a highly water-repellent material such as a copolymer of perfluoroethylene and perfluoropropylene can also be used.

In order to form another water-repellent layer, a slurry was prepared by adding pitch fluoride powder, one of the materials having high water repellency, to an organic solvent based on acetone. This slurry was applied on the same carbon paper as above, and dried to form a water-repellent layer. The fluorinated pitch used was obtained by reacting a coal-based pitch with a fluorine gas. The water-repellent layer composed of the fluorinated pitch powder had a thickness of about 20 μm, and the carbon paper was partially exposed.
On the side of the water repellent layer forming side of the carbon paper, the catalyst layer was formed in an amount of platinum of 0.5 mg / cm ^{2 in the same} manner as above.
Coating with a thickness of Pitch fluoride is a molecular crystal and is dissolved in a fluorine-based solvent such as perfluorobenzene. Therefore, a water-repellent layer could be formed also by a method in which the solution was atomized by a spray device, applied to one side of carbon paper, and dried.

The following method was used as another method for forming a water-repellent layer. The PTFE sheet was stretched to a thickness of about 35 μm, and this sheet was attached to one surface of carbon paper by hot pressing. By changing the hot pressing conditions, the gas permeability of the carbon paper having the water-repellent layer formed thereon could be controlled. Increasing the pressure and temperature of the hot press increased the number of holes for direct electrical contact between the catalyst layer and the electrode substrate, that is, the exposed portion of the carbon paper. Further, as another method for forming a water-repellent layer, a number of holes having a diameter of 0.5 to 1.0 mm were punched out in an expanded PTFE sheet before joining to a carbon paper. As a result, a hole in which the catalyst layer and the electrode substrate were in direct contact was reliably formed. With respect to the intervals between the holes formed in the PTFE sheet, prototypes were prepared from the smaller (2 mm) to the larger (1 to 3 mm) gas passages formed on the carbon separator. In this method, in addition to the expanded PTFE sheet, a porous PTFE sheet used as a sealing material, or a sheet in which fibers made of a microscopically water-repellent material are entangled to form a network-like structure are applied. Is possible. A catalyst layer was coated with a 0.5 mg / cm ² platinum layer on carbon paper to which a sheet of the water-repellent material punched out in this manner was joined by hot pressing.

The above four types of electrodes, namely, (a) P
A water-repellent layer was formed by spraying an aqueous dispersion of TFE, (b) a water-repellent layer was formed from pitch fluoride powder, and (c) an expanded PTFE sheet was joined to form a water-repellent layer. And (d) perforated perforated carbon sulfonic acid polymer electrolyte membranes having a hydrogen ion conductivity (Nafion membrane, manufactured by DuPont) , Film thickness 2
5μm), temperature 125 ° C, pressure 20kgf / cm
² and hot-press the electrolyte membrane-electrode assembly (ME
A) was prepared. The electrode area was 5 cm × 5 cm. These MEAs are sandwiched between carbon separators,
A fuel cell was assembled by arranging a silicone rubber gasket in the four areas. Batteries using the above electrodes a, b, c, and d are referred to as A, B, C, and D, respectively.

Next, performance tests of these batteries were performed.
The result is shown in FIG. The test conditions of the battery were as follows. Pure hydrogen was used as the fuel gas, and air was used as the oxidant gas, and each was supplied to the electrode after being humidified by bubbling in water. 70% hydrogen utilization, 30% air utilization, 75 ° C battery temperature, 0.7 A / cm current density
^2. The temperature of the water used for humidification on the anode side (hereinafter referred to as bubbler temperature) was set to 75 ° C. In FIG. 2, the bubbler temperature on the cathode side is plotted on the horizontal axis, and the influence of the humidification condition of the oxidizing gas supplied to the cathode on the battery performance was evaluated. As is clear from FIG. 2, the battery A using the electrodes (a) to (d) according to the present invention is compared with the battery E using the conventional electrode (e) in which the catalyst layer and the electrode substrate are directly joined. -D show that the performance is improved when the bubbler temperature is low, that is, when dry air is supplied. Also,
In the battery D using the electrode (d), it was found that the performance was higher when the interval between the holes provided in the expanded PTFE sheet was smaller than the width of the gas flow path.

Example 2 In Example 1, it was shown that by arranging a water-repellent layer between a catalyst layer and an electrode substrate, battery performance could be improved when low humidified air was used. Therefore, in this embodiment, in order to improve the battery performance when high humidified air is used, a process of increasing the surface area of the electrode substrate was performed. In this example, carbon paper made of polyacrylonitrile-based carbon fiber was used as the electrode substrate. First, 5 of carboxymethylcellulose (CMC)
A weight% aqueous solution was rubbed against the carbon paper and dried. Heat treatment was performed at 800 ° C. for 6 hours while flowing nitrogen gas to carbonize CMC. By repeating this process three times, the carbide of CMC was made to adhere to the carbon fibers in the carbon paper as the electrode substrate. When this surface treatment is performed, the specific surface area of the carbon paper becomes 3,500 c
m ² / g, the value of untreated carbon paper 2,
It was about 1.5 times as large as 300 cm ² / g. CM
When an ethyl alcohol solution of polyvinyl butyral was used in place of C, the specific surface area became 3,700 cm ² / g. When the atmosphere gas during the above heat treatment was air, the specific surface area was conversely reduced. The above heat treatment needs to be performed in a gas having a low oxidizing property.

Next, in order to increase the specific surface area, carbon powder having a high specific surface area was introduced into the electrode substrate. A paste obtained by adding ethanol to acetylene black powder (specific surface area: 60 m ² / g) and kneading the mixture was rubbed with carbon paper and dried, and then fired at 800 ° C. for 4 hours in a nitrogen stream. The specific surface area of the carbon paper obtained by this method was 2,400 cm ² / g. The following method was also attempted in order to further firmly fix the carbon powder to the carbon fiber. 1 g of acetylene black powder (specific surface area: 60 m ² / g) was added to 100 g of a 5% by weight aqueous solution of CMC and kneaded to form a paste. The paste was rubbed into carbon paper, dried, and fired. As a result, the specific surface area of the electrode substrate was about 28,000 cm ² / g. further,
As another attempt to increase the specific surface area, a carbon fiber activation treatment was performed. As the activation method, the following steam activation was employed. While flowing nitrogen into the electric furnace, steam was introduced into the carbon paper heated to 1,000 ° C. 30-6
During 0 seconds, steam was introduced and then cooled. The specific surface area of the substrate subjected to this treatment was about 100 to 200 m ² / g.

Onto these carbon papers, the same ink for preparing a catalyst layer as in Example 1 was applied with a platinum layer of 0.5 mg / cm ² . An MEA was produced by sandwiching the electrolyte membrane between the pair of carbon papers thus obtained and hot pressing.
The battery assembled from this MEA was tested under the same conditions as in Example 1. FIG. 3 shows the result. Batteries provided with an electrode to which CMC carbide was attached, an electrode into which carbon powder had been introduced, and an electrode using activated carbon paper were designated F, G, and H, respectively. The performance of the battery E of the conventional configuration using the carbon paper not subjected to the process of increasing the specific surface area rapidly decreased as the supplied air humidified amount increased. This is because the generated water stagnates in the catalyst layer and the carbon paper, and the supply of air is hindered. On the other hand, in the case of batteries using carbon paper that has been subjected to a process of increasing the specific surface area, the performance of any of the batteries was improved where the amount of supplied air was high.

Next, the battery operation was continued while maintaining the bubbler temperature on the air side at 65 ° C., and then the bubbler temperature was reduced to 40 ° C.
To change the battery voltage. As shown in FIG. 4, the voltage of each of the batteries dropped to 0.3 V or less after 10 minutes. Conventional batteries in which the specific surface area expansion treatment was not performed on the electrode substrate rapidly deteriorated in battery performance immediately after the bubbler temperature was switched, whereas the battery according to the present invention exhibited performance for several minutes after the bubbler temperature was switched. Maintained. This is because the water retention capacity of carbon paper has increased as its specific surface area has increased, and even if dry air is supplied, the catalyst layer and electrolyte membrane do not immediately dry and maintain battery performance. It depends on what you can do. In an actual fuel cell power generation system, a situation is assumed in which a dry gas is temporarily supplied when the system starts up or shuts down, or when the compatibility with the fuel reformer or humidifier becomes poor. . Even in such a case, the battery according to the present invention does not fall into the system down for a short time.

Here, carbon paper made of PAN-based carbon fiber is used as the electrode base material. However, the present invention is also applied to pitch-based carbon fiber or carbon cloth and carbon felt composed of various carbon particles. By increasing the surface area, battery performance can be stabilized against gas humidification conditions.

Embodiment 3 A polymer electrolyte fuel cell is
The humidity differs between the upstream side and the downstream side of the supply gas inside the electrode. In order to keep the current density as uniform as possible over the entire area of the electrode and obtain high battery performance, it is necessary to have an MEA configuration in which the performance does not decrease even when the humidity of the supply gas flowing through the gas flow path changes. Therefore, in this example, an MEA was formed in which the water-repellent layer shown in Example 1 was formed on the carbon paper having an increased specific surface area shown in Example 2. As a means for increasing the specific surface area of the carbon paper, the above-mentioned steam activation treatment was used, and the water-repellent layer was formed by the above-mentioned hot pressing method of the expanded PTFE sheet. The other conditions were the same as in Example 1 to assemble the fuel cell. FIG. 5 shows the test results of the battery. The test conditions were the same as in Example 1. Compared with the conventional battery E, the performance of the battery I according to the present embodiment was significantly improved even when the supplied air was dry.

Next, a process for increasing the surface area of the electrode substrate,
For a battery having a configuration in which the water-repellent layer was simultaneously introduced, a test was conducted by assembling a laminated battery. A calcined carbon plate having a thickness of 4 mm was cut to form a gas flow path on one side and a cooling water flow path on the other side. This carbon separator and MEA having an electrode area of 100 cm ² were alternately laminated to form a laminated battery in which 10 cells were connected in series. End plates made of stainless steel were applied to both ends of the laminated battery, and both end plates were fastened with bolts and nuts at a pressure of 20 kgf / cm ² . Other configurations were the same as those of the first embodiment. Example 1
As a result of the test under the same conditions as in the above, as in the single cell test, the battery had sufficient performance even when the supply air was dry, and the output variation of each cell was significantly improved. That is, when 10 cells are stacked in the conventional battery, when the load is 0.5 A / cm ² , the variation of the output voltage is ± 5.
In contrast to 0 mV, the battery of this example had a variation in output voltage of ± 30 mV. In a stacked battery,
The gas is supplied to each cell in parallel, but the flow rate of the gas varies due to subtle variations in the channel configuration of each cell and the wettability of the electrodes. For cells with low gas flow,
It is considered that a significant difference in humidification between the upstream side and the downstream side of the supply gas is one of the causes of the performance variation. This was found to be improved in the laminated battery of the present invention.

In the above Examples 1, 2 and 3, the effect on the stability of the battery performance under the humidifying condition on the cathode side was shown. However, even on the anode side, hydrogen gas is consumed in the middle of the gas flow path of the unit cell, and the downstream region is more likely to be over-humidified than the upstream region. This tendency is more remarkable as the utilization rate increases, and it goes without saying that the present invention is effective in improving the performance as in the case of the cathode side.

[0028]

As described above, according to the present invention, it is possible to provide a polymer electrolyte fuel cell which maintains high performance regardless of a change in vapor pressure of water vapor contained in a supply gas. Further, the present invention can contribute to stabilization of operating conditions of the fuel cell, improvement of system efficiency, and the like.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing an MEA of the present invention.

FIG. 2 is a diagram showing the performance of a polymer electrolyte fuel cell according to a first embodiment of the present invention.

FIG. 3 is a diagram showing the performance of a polymer electrolyte fuel cell according to a second embodiment of the present invention.

FIG. 4 is a diagram illustrating another performance of the polymer electrolyte fuel cell according to the second embodiment of the present invention.

FIG. 5 is a diagram showing the performance of a polymer electrolyte fuel cell according to a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polymer electrolyte membrane 2 Catalyst layer 3 Electrode substrate 4 Water-repellent layer 5 Through-hole

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Eiichi Yasumoto 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Hiroki Kusakabe 1006 Kadoma Kazuma Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Inventor Yasushi Sugawara 1006 Kadoma, Kazuma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. (72) Inventor Yoshihiro Hori 1006 Kadoma, Kazuma, Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. AS03 DD05 EE05 EE18 HH03 5H026 AA06 CX02 EE19 HH03

Claims (3)

[Claims] An oxidant gas is supplied to a polymer electrolyte membrane, a pair of electrodes sandwiching the polymer electrolyte membrane, an anode separator having a gas flow path for supplying a fuel gas to one electrode, and an other electrode. Comprising a cathode-side separator having a gas flow path, wherein the electrode is a catalyst layer in contact with the polymer electrolyte membrane, an electrode substrate having gas permeability and electron conductivity, and the catalyst layer and the electrode substrate A polymer electrolyte type comprising a water repellent layer interposed therebetween, wherein the water repellent layer has a plurality of through holes, and the catalyst layer and the electrode substrate are electrically connected through the through holes. Fuel cell. 2. The polymer electrolyte fuel cell according to claim 1, wherein the through holes are distributed such that an average interval between the holes is smaller than a width of a gas passage of the separator. 3. The polymer electrolyte fuel cell according to claim 1, wherein the electrode substrate is made of carbon fiber subjected to a surface area increasing treatment.