JP2003178774A - Fuel-cell unit and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel-cell unit, which shows the high cell characteristic, and its manufacturing method even if an electrolyte layer, which consists of proton conductive gel, is created by the sol-gel process, cracks do not occur in the electrolyte layer, but the adhesion nature of a catalyst layer and the electrolyte layer is good. <P>SOLUTION: As for the fuel-cell unit, which has the cell structure which allotted the catalyst layer and the gas diffusion layer to this order on both faces of the main face of the electrolyte layer, respectively, the above electrolyte layer consists of proton-conductive gel, and it makes a layer, which consists of ion-exchange resin, exist at least in a part, which touches the inside of the catalyst layer or the catalyst layer. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell unit having an electrolyte layer made of a proton conductive gel and a method for producing the same.

[0002]

2. Description of the Related Art A fuel cell has a cell structure in which an electrolyte layer is sandwiched between a fuel electrode catalyst layer and an air electrode catalyst layer on both sides of a main surface, and this is arranged between two gas diffusion layers. A reaction gas containing oxygen and a reaction gas containing oxygen (oxidant gas) are supplied to the air electrode side to react hydrogen with oxygen to generate power. Air is generally used as the reaction gas supplied to the air electrode side. As the reaction gas supplied to the fuel electrode side, in addition to pure hydrogen gas, fuel gas such as natural gas or light hydrocarbon such as naphtha is used as a fuel gas reforming system (reformer, CO modifier, C
A hydrogen-rich reformed gas that has been reformed by using an O remover or the like) is used.

Various types of electrolyte layers are used. Among them, a polymer electrolyte fuel cell using a solid polymer membrane made of a cation exchange resin as an electrolyte is used for vehicles, mobile phones, households. Widely applied as a power source for business.

On the other hand, in recent years, a proton conductive gel has been studied as an electrolyte for fuel cells. This proton-conducting gel is mainly composed of silicon oxide and Bronsted acid (phosphoric acid, etc.) prepared by a sol-gel method, as disclosed in, for example, JP-A-8-249923 and JP-A-11-203936. The fuel cell using the compound as an electrolyte has a higher operating temperature (150 ° C) than the operating temperature (about 60 to 100 ° C) of the polymer electrolyte fuel cell.
Power can be generated at (° C). Therefore, like the conventional polymer electrolyte fuel cell, the high-temperature reformed gas from the fuel gas reforming system is supplied to the operating temperature (about 60 to 100 ° C.) of the fuel cell.
Therefore, it is not necessary to cool it significantly, and the thermal efficiency for power generation can be dramatically improved. In a polymer electrolyte fuel cell, internal resistance increases and power generation efficiency decreases if the polymer electrolyte membrane is not sufficiently wet, but the proton conductive gel requires more water than the polymer electrolyte membrane during power generation. In other words, stable power generation is possible even at relatively high temperatures compared to polymer electrolyte fuel cells. Thus, it is considered that the use of the above-mentioned proton-conducting gel in the electrolyte can solve many of the problems of the polymer electrolyte fuel cell.

[0005]

As shown in FIGS. 4 (A) to 4 (C), in order to prepare an electrolyte layer (membrane) made of this proton conductive gel by the sol-gel method, the fuel electrode catalyst layer is usually used. A sol is provided between (for example, a sheet in which platinum-supporting carbon particles and polytetrafluoroethylene (PTFE) are mixed) and an air electrode catalyst layer (for example, a sheet in which platinum-supporting carbon particles and polytetrafluoroethylene (PTFE) are mixed). It is performed by pouring and gelling. That is, first, as shown in FIG. 4 (A), a gas diffusion layer (for example, carbon paper filled with carbon powder and polytetrafluoroethylene powder)
1. A fuel electrode catalyst layer 2 and a gas diffusion layer 3 (for example, the same as the gas diffusion layer 1) joined and laminated 1 are joined and laminated, and an air electrode catalyst layer 4 is laminated via a spacer (polytetrafluoroethylene tape) 5 4B, the sol 6 is immersed in the sol 6, the sol is poured between the fuel electrode catalyst layer 2 and the air electrode catalyst layer 4, and the sol is poured.
As shown in (C), for example, the fuel cell unit 8 using the proton conductive gel in the electrolyte layer 7 is prepared by gelling the solvent by natural drying in the air.
However, there is a problem that cracks 9 occur in the electrolyte layer 7 thus formed, and the reaction gas leaks (cross leaks) through the cracks 9, and the catalyst layers 2 and 4 and the electrolyte layer 7 There is a problem that the cell characteristics are deteriorated due to poor adhesion with.

A first object of the present invention is to solve the above-mentioned problems of the prior art, and even if an electrolyte layer (membrane) made of a proton conductive gel is prepared by the sol-gel method, cracks do not occur in the electrolyte layer, A second object of the present invention is to provide a fuel cell unit having good adhesion between the catalyst layer and the electrolyte layer and high cell characteristics. A second object of the present invention is to provide such a fuel cell unit easily and economically. It is to provide a method of manufacturing.

[0007]

Means for Solving the Problems As a result of intensive studies for solving the conventional problems, the present inventors have found that a layer made of an ion-exchange resin is present in the catalyst layer or in at least a part in contact with the catalyst layer. It has been found that the problem can be solved by forming an electrolyte layer (membrane), and further, after forming a layer made of an ion exchange resin in at least part of the inside of the catalyst layer or in contact with the catalyst layer to form the electrolyte layer (membrane), The inventors have found that the problem can be solved by removing the ion exchange resin, and completed the present invention.

That is, the fuel cell unit according to claim 1 of the present invention for solving the above problem has a cell structure in which a catalyst layer and a gas diffusion layer are arranged in this order on both sides of the main surface of the electrolyte layer. In the fuel cell unit, the electrolyte layer is made of a proton conductive gel, and at least a part of the inside of the catalyst layer or in contact with the catalyst layer,
It is characterized by the presence of a layer of ion exchange resin.

The fuel cell unit according to claim 2 of the present invention is the fuel cell unit according to claim 1, wherein the proton conductive gel is SiO ₂ , Al ₂ O.
₃ , a material selected from TiO ₂ , V ₂ O ₅ , and ZrO ₂ and a material selected from phosphoric acid, perchloric acid, boric acid, and silicic acid.

According to a third aspect of the present invention, when manufacturing a fuel cell unit having a cell structure in which a catalyst layer and a gas diffusion layer are arranged in this order on both sides of the main surface of the electrolyte layer, the inside of the catalyst layer or the catalyst is formed. A method for producing a fuel cell unit, characterized in that an electrolyte layer made of a proton conductive gel is formed in a state where a layer made of an ion exchange resin is provided on at least a part in contact with the layer.

According to a fourth aspect of the present invention, when a fuel cell unit having a cell structure in which a catalyst layer and a gas diffusion layer are arranged in this order on both sides of the main surface of an electrolyte layer, the inside of the catalyst layer or the catalyst is produced. A fuel cell, characterized in that an electrolyte layer made of a proton conductive gel is formed in a state where a layer made of an ion exchange resin is provided on at least a part in contact with the layer, and then the layer made of the ion exchange resin is removed. This is the manufacturing method of the unit.

According to a fifth aspect of the present invention, in the method for producing a fuel cell unit according to the third or fourth aspect, the proton conductive gel is SiO ₂ , Al ₂ O ₃ or Ti.
It is characterized by containing a material selected from O ₂ , V ₂ O ₅ and ZrO ₂ and a material selected from phosphoric acid, perchloric acid, boric acid and silicic acid.

By forming a layer made of an ion-exchange resin in at least a part of the inside of the catalyst layer or in contact with the catalyst layer to form an electrolyte layer, or at least in a part of the inside of the catalyst layer or in contact with the catalyst layer, After creating an electrolyte layer with a layer consisting of an exchange resin, by removing this ion exchange resin, cracks do not occur in the electrolyte layer, good adhesion between the catalyst layer and the electrolyte layer, high cell A fuel cell unit having characteristics can be provided.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. 1 (A) to 1 (C) are explanatory views schematically explaining a process of producing a fuel cell unit which is the first embodiment of the present invention. FIG. 2 is an assembly explanatory diagram of a fuel battery cell unit stack assembled using the fuel battery cell unit shown in FIG. Figure 3
(A)-(D) is explanatory drawing which illustrates typically the process of producing the fuel cell unit which is the 2nd Embodiment of this invention. In FIGS. 1 to 3, the same components as those shown in FIG. 4 are designated by the same reference numerals, and a duplicate description will be omitted.

(First Embodiment of the Invention) As shown in FIG. 1A, except that a layer 10 made of an ion exchange resin is provided on each of the fuel electrode catalyst layer 2 and the air electrode catalyst layer 4. ,
The fuel cell unit 11 of the present invention is prepared in the same manner as in FIGS. 4 (A) to 4 (C). The electrolyte layer 7 thus formed is uniform, there are no cracks in the electrolyte layer 7, and the adhesion between the catalyst layers 2 and 4 and the electrolyte layer 7 is good, and the fuel cell unit 11 of the present invention is high. It has cell characteristics. Since the layer 10 made of the ion exchange resin is provided at the joint interface between the electrolyte layer 7 and the catalyst layers 2 and 4, the sulfone group or the like located at the end of the ion exchange resin is chemically bonded to the gel, and the catalyst layer 2, It is considered that the adhesion between No. 4 and the electrolyte layer 7 is improved. Further, it is considered that the removal of the solvent in the sol during the gel formation process smoothly takes place through the hydrophilic clusters associated with the sulfone groups and the like, so that the electrolyte layer 7 having few cracks is formed. Of course, it is not limited to these ideas.

The ion exchange resin used in the present invention is
Specifically, for example, a perfluorocarbon sulfonic acid polymer (manufactured by DuPont, USA, trade name: Nafion),
Perfluorocarbon carboxylic acid polymer, styrene sulfonic acid-divinylbenzene copolymer, styrene sulfonic acid-butadiene copolymer, polystyrene sulfonic acid-polyvinyl alcohol copolymer, polystyrene sulfonic acid-ethylene vinyl alcohol copolymer, sulfonated polyethylene, fluorocarbon sulfonic acid and polyvinylidene Examples thereof include a mixture of fluoride, a fluorocarbon matrix grafted with trifluoroethylene, and a mixture of two or more of these.

As shown in FIG. 2, the fuel cell unit laminate 20 has a structure in which the fuel cell unit 11 is laminated between the air electrode side channel plate 15 and the fuel electrode side channel plate 16. The fuel cell unit 11 has a layer 10 made of an ion exchange resin, an air electrode catalyst layer 4, a gas diffusion layer 3 on one surface of the electrolyte layer 7, and a layer 10 made of an ion exchange resin on the other surface, a fuel electrode catalyst layer. 2. The gas diffusion layer 1 is sequentially joined and laminated. The fuel cell is assembled into a structure (cell stack) in which a plurality of laminated bodies 20 are laminated and both ends thereof are fixed by a pair of end plates so that high-power electric power can be taken out. The air electrode catalyst layer 4 and the fuel electrode catalyst layer 2 are formed of, for example, a mixture of catalyst-supporting particles (platinum-supporting carbon particles and polytetrafluoroethylene (PTFE)).

The gas diffusion layers 1 and 3 used in the present invention are, for example, a base material (carbon paper) having a thickness of about 200 μm and a water repellent resin (for example, tetrafluoroethylene-hexafluoropropylene copolymer ( FEP)) is applied and carbon powder is filled in this. The gas diffusion layers 1 and 3 are also called current collectors, and ensure the flow of current between the air electrode catalyst layer 4, the fuel electrode catalyst layer 2, and the channel plates 15 and 16.

The fuel electrode side channel plate 16 is a member formed by injection-molding a mixture of carbon powder with a resin material such as phenol resin and has a surface facing the fuel electrode side gas diffusion layer 1 in the x direction. The ribs 166 are juxtaposed at regular intervals in the y direction with the longitudinal direction as the longitudinal direction, thereby forming a channel 165 through which the fuel gas (hydrogen or hydrogen-rich reformed gas) flows.

The air electrode side channel plate 15 is substantially the same member as the fuel electrode side channel plate 16, and is arranged on the surface facing the air electrode side gas diffusion layer 3 at regular intervals in the x direction with the y direction as the longitudinal direction. Ribs (not shown) are installed side by side,
As a result, channels are formed to allow the oxidant gas (oxidant such as air) to flow in the same direction.

The components 1 to 16 have openings (131) at the four corners of each main surface to form an internal manifold.
~ 134, 151-154, 161-163 are shown), of which the openings 161, 131,
Reactant gas (fuel gas) is supplied to the channel 165 of the fuel electrode side channel plate 16 by the opening portion including 151 and extending in the z direction, and the opening portion including the opening portions 163, 133 and 153 and extending in the z direction. Thereby supplying a reaction gas (oxidant gas such as air) to a channel (not shown) of the air electrode side channel plate 15, and the openings 132, 162, 15 are formed.
It is discharged through the open hole portion including 2 in the z direction.

During operation of such a fuel cell, the fuel electrode side
Hydrogen gas (hydrogen-rich reformed gas), air on the air electrode side
To supply. This causes hydrogen to become a proton at the fuel electrode.
(H ₂ → 2H⁺ + 2e^- ), In the gel of the electrolyte layer 7
To the air electrode side. On the other hand, oxygen in the air moves
Reacts with incoming protons to produce water (2H⁺ + 2e^-+
1 / 2O₂ → H₂ O). Little water in the electrolyte layer 7
Even if it contains no
The roton is conducted and the power generation reaction is performed.

The electrolyte layer 7 is made of a proton conductive gel.
SiO₂ , Al₂ O₃ , TiO ₂ , V₂ O_Five , Zr
O₂ Materials selected from among
Substance) and Bronsted acid (phosphoric acid, perchloric acid, boric acid,
Of compounds that act as proton donors such as silicic acid)
Bronsted acid comprising a material selected from
High concentration of hydroxyl groups on the terminal surface of silicon oxide etc.
It has a chemical structure that is bound in degrees.

The electrolyte layer 7 is produced by the sol-gel method. First, a solution (sol) of a proton conductive material (for example, ethyl silicate Si (OC ₂ H ₅ ) ₄ + trimethyl phosphate P)
O (OCH ₃ ) ₃ + water + ethanol C ₂ H ₅ OH + hydrochloric acid HCl were mixed (hydrolyzed) at a molar ratio of 1: 0.04: 1: 1: 0.0027, and this solution was mixed with water + ethanol C. ₂ H ₅ OH + HCl is mixed at a molar ratio of 4: 1: 0.011 to 1 mol of ethyl silicate,
A sol is prepared by stirring for 1 hour), and the solvent in the sol is naturally dried in the air to cause gelation by a polycondensation reaction.

(Second Embodiment of the Invention) As shown in FIG. 3 (A), the gas diffusion layers 1 and 3 are filled with the ion exchange resin by coating, impregnating, and drying the ion exchange resin solution. 4A to 4C except that the layer 10 made of an ion exchange resin is provided on at least part of the catalyst layers 2 and 4 in contact with each other.
In the same manner as in (C), the fuel cell unit having the electrolyte layer 7 made of the proton conductive gel shown in FIG. 3 (C) is prepared. Thereafter, the layer 10 made of the ion exchange resin is dissolved in methanol and removed by immersing the fuel cell unit shown in FIG. 3 (C) in methanol to prepare the fuel cell unit 12 of the present invention. To do. The electrolyte layer 7 formed in this way is uniform and
There are no cracks in the inside, and the adhesion between the catalyst layers 2 and 4 and the electrolyte layer 7 is good, and the fuel cell unit 1 of the present invention is
2 has high cell characteristics.

The above description of the embodiments is for explaining the present invention, and does not limit the invention described in the claims or reduce the scope thereof. Further, the configuration of each part of the present invention is not limited to the above embodiment, but various modifications can be made within the technical scope described in the claims.

[0027]

EXAMPLES The contents of the present invention will be described more specifically below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples without departing from the gist of the present invention. (Example 1) Ethyl (Sol Preparation) silicate _{Si (OC 2 H 5) 4} + trimethyl phosphate PO (OCH _{3) 3} + water + ethanol C ₂ H ₅ OH +
HCl with a molar ratio of 1: 0.04: 1: 1: 0.002
Mixed (hydrolyzed) at a ratio of 7. Water + ethanol C ₂ H ₅ OH + hydrochloric acid HCl
In a molar ratio of 4: 1 to 1 mol of ethyl silicate.
The mixture was mixed at a ratio of 0.011 and stirred for 1 hour to prepare a sol. (Pretreatment of carbon paper) Carbon paper was impregnated with 16% by mass of tetrafluoroethylene-hexafluoropropylene copolymer (FEP) and then heat-treated at 380 ° C for 1 hour. (Preparation of Fuel Cell Unit of the Present Invention) Carbon powder and PTF are prepared from both sides of pretreated carbon paper.
A slurry prepared by mixing E powder at a mass ratio of 60:40 was applied and filled in carbon paper. After that, 360 ℃
And heat treated for 2 hours. Next, this heat-treated carbon paper (gas diffusion layer), platinum-supporting carbon powder and PTF
E powder mixed at a mass ratio of 70:30 and formed into a sheet (catalyst layer), a layer made of an ion exchange resin (trade name: Go
A re-select film and a thickness of 20 μm) were stacked in this order and bonded by hot pressing at 150 ° C. and 20 kgf / cm ² for 10 seconds.

Next, FIG. 1 (B) shows a state in which two sheets (fuel electrode side and air electrode side) thus produced are stacked as shown in FIG. 1 (A). After soaking in the sol, the solvent in the sol is naturally dried in the air to cause gelation, and as shown in FIG. The electrolyte layer 7 made of gel was produced to prepare the fuel cell unit 11 of the present invention.

(SEM Observation of Cross Section of Electrolyte Layer 7) A cross section of the electrolyte layer 7 made of the proton conductive gel of the fuel cell unit 11 of the present invention is taken by an electron microscope (scanning electron microscope S).
-2300, manufactured by Hitachi, Ltd., accelerating voltage 20k
v, Emission current 120 μA,
The result of observation at a magnification of 500 is shown in FIG.

(Cell characteristic test) Operating temperature is 120 ° C., hydrogen is used as fuel, air is used as oxidant gas, and electrode area is 9
FIG. 7 shows the cell voltage-current characteristics of the fuel cell unit 11 of the present invention of cm ² .

The electrolyte layer 7 of the fuel cell unit 11 of the present invention is uniform, there are few cracks in the electrolyte layer 7, and the adhesion between the catalyst layers 2 and 4 and the electrolyte layer 7 is good and has high cell characteristics. .

Example 2 (Preparation of Fuel Cell Unit of the Present Invention) Carbon paper pretreated in Example 1 was coated with an ion-exchange resin (Dupont, USA, trade name: Nafion) solution, An ion exchange resin was filled inside the carbon paper by drying. Then, it heat-processed at 150 degreeC for 1 hour. Next, this carbon paper (gas diffusion layer)
And platinum supporting carbon powder and PTFE powder in a mass ratio of 7
What was mixed and sheeted at 0:30 (catalyst layer) was 1
Bonding was performed by hot pressing at 50 ° C. and 20 kgf / cm ² for 10 seconds.

Next, FIG. 3 (B) shows a state in which two sheets (fuel electrode side and air electrode side) thus produced are superposed as shown in FIG. 3 (A). After soaking in the sol, the solvent in the sol is allowed to gel while naturally drying in the atmosphere, and as shown in FIG.
An electrolyte layer 7 made of a proton conductive gel was formed between the cathode electrode layer 4 and the air electrode catalyst layer 4. The cell unit thus prepared was immersed in methanol and placed in an autoclave for 20
After treatment at 0 ° C. and 200 atm for 1 hour, the ion-exchange resin filled in the carbon paper is dissolved and removed, and then the carbon paper shown in FIG.
The fuel cell unit 12 of the present invention shown in (D) was produced.

FIG. 7 shows the result of testing the cell characteristics of the fuel cell unit 12 of the present invention in the same manner as in Example 1. The electrolyte layer 7 of the fuel cell unit 12 of the present invention is uniform, there are few cracks in the electrolyte layer 7, the adhesion between the catalyst layers 2 and 4 and the electrolyte layer 7 is good, and high cell characteristics are obtained.

(Comparative Example 1) (Preparation of fuel cell unit for comparison) Example 1
From both sides of the carbon paper pretreated in
A slurry prepared by mixing carbon powder and PTFE powder at a mass ratio of 60:40 was applied and filled in carbon paper. Then, it heat-processed at 360 degreeC for 2 hours. Next, this heat-treated carbon paper (gas diffusion layer) and platinum-supported carbon powder and PTFE powder were mixed at a mass ratio of 70:30 and formed into a sheet (catalyst layer) at 150 ° C., 20
Bonding was carried out by hot pressing for 10 seconds at kgf / cm ² .

Next, FIG. 4B shows a state in which two sheets (fuel electrode side and air electrode side) thus manufactured are stacked as shown in FIG. 4A. After soaking in the sol, the solvent in the sol is allowed to gel while naturally drying in the atmosphere, and as shown in FIG.
An electrolyte layer 7 made of a proton conductive gel was formed between the cathode electrode layer 4 and the air electrode catalyst layer 4 to prepare a fuel cell unit 8 for comparison.

FIG. 6 shows the result of observing the cross section of the electrolyte layer 7 made of the proton conductive gel of the fuel cell unit 8 for comparison with an electron microscope in the same manner as in Example 1.
Moreover, the result of having tested the cell characteristic of the fuel cell unit 8 for comparison similarly to Example 1 is shown in FIG. The electrolyte layer 7 of the fuel cell unit 8 for comparison is non-uniform, cracks 9 are generated in the electrolyte layer 7, and the adhesion between the catalyst layers 2 and 4 and the electrolyte layer 7 is poor.
Poor cell characteristics.

Fuel cell unit 1 of Examples 1 and 2
Nos. 1 and 12 have a higher open circuit voltage than the fuel cell unit 8 for comparison, and the cell voltage is high at all current densities (within the measurement range). This is because the electrolyte layer 7 of the fuel cell units 11 and 12 of Examples 1 and 2 was uniform and
This is because there were few cracks inside and the cross leak of the reaction gas was reduced. The fuel cell unit 12 of the second embodiment has a higher cell voltage on the higher current density side than the fuel cell unit 11 of the first embodiment. This is because the gas diffusion layers 1 and 3 of the fuel cell unit 12 of the second embodiment are the same. It is considered that the gas diffusivity of is slightly high. The adhesion between the catalyst layers 2, 4 and the electrolyte layer 7 of the fuel cell units 11, 12 of Examples 1 and 2 is the adhesion between the catalyst layers 2, 4 and the electrolyte layer 7 of the fuel cell unit 8 for comparison. It was confirmed that it was significantly improved compared to sex.

[0039]

The fuel cell unit according to claim 1 of the present invention is a fuel cell unit having a cell structure in which a catalyst layer and a gas diffusion layer are arranged in this order on both sides of the main surface of an electrolyte layer. The electrolyte layer is made of a proton conductive gel, and at least a part of the inside of the catalyst layer or in contact with the catalyst layer has a layer made of an ion exchange resin, so that an electrolyte layer made of a proton conductive gel is prepared by a sol-gel method. In addition, cracks do not occur in the electrolyte layer, the adhesion between the catalyst layer and the electrolyte layer is good, and high cell characteristics are exhibited, which is a remarkable effect.

A fuel cell unit according to a second aspect of the present invention is the fuel cell unit according to the first aspect, wherein the proton conductive gel is SiO ₂ , Al ₂ O.
_3. A material selected from the group consisting of ₃ , TiO ₂ , V ₂ O ₅ and ZrO ₂ and a material selected from phosphoric acid, perchloric acid, boric acid and silicic acid. In addition to the same effect as that of the fuel cell unit of No. 3, it has a further remarkable effect of being superior in proton conductivity.

According to a third aspect of the present invention, when manufacturing a fuel cell unit having a cell structure in which a catalyst layer and a gas diffusion layer are arranged in this order on both sides of the main surface of the electrolyte layer, the inside of the catalyst layer or the catalyst is produced. The fuel cell unit manufacturing method according to claim 1, wherein an electrolyte layer made of a proton conductive gel is formed in a state in which a layer made of an ion exchange resin is provided on at least a part in contact with the layer. The remarkable effect that a battery cell unit can be manufactured easily and economically is produced.

According to a fourth aspect of the present invention, when manufacturing a fuel cell unit having a cell structure in which a catalyst layer and a gas diffusion layer are arranged in this order on both sides of the main surface of the electrolyte layer, the inside of the catalyst layer or the catalyst is produced. A fuel cell, characterized in that an electrolyte layer made of a proton conductive gel is formed in a state where a layer made of an ion exchange resin is provided on at least a part in contact with the layer, and then the layer made of the ion exchange resin is removed. A unit manufacturing method, even if an electrolyte layer made of a proton conductive gel is prepared by the sol-gel method, cracks do not occur in the electrolyte layer, good adhesion between the catalyst layer and the electrolyte layer, and high cell characteristics. The remarkable effect is that the fuel cell unit having the above can be manufactured easily and economically.

According to a fifth aspect of the present invention, in the method for producing a fuel cell unit according to the third or fourth aspect, the proton conductive gel is SiO ₂ , Al ₂ O ₃ or Ti.
Since it contains a material selected from O ₂ , V ₂ O ₅ , and ZrO ₂ and a material selected from phosphoric acid, perchloric acid, boric acid, and silicic acid, it is said to be superior in proton conductivity. Has a further remarkable effect.

[Brief description of drawings]

FIG. 1A to FIG. 1C are explanatory views schematically explaining a process of producing a fuel cell unit which is a first embodiment of the present invention.

FIG. 2 is an assembly explanatory diagram of a fuel cell unit laminated body assembled using the fuel cell unit shown in FIG.

3 (A) to 3 (D) are explanatory views schematically illustrating a process of producing a fuel cell unit which is a second embodiment of the present invention.

4 (A) to 4 (C) are explanatory views schematically illustrating a process of producing a conventional fuel cell unit.

FIG. 5 is an electron micrograph showing a cross section of an electrolyte layer of a fuel cell unit of the present invention.

FIG. 6 is an electron micrograph showing a cross section of an electrolyte layer of a conventional fuel cell unit.

FIG. 7 is a graph showing cell voltage-current characteristics.

[Explanation of symbols]

1, 3 gas diffusion layer 2 Fuel electrode catalyst layer 4 Air electrode catalyst layer 5 spacers 6 sol 7 Electrolyte layer 8, 11, 12 Fuel cell unit 9 crack 10 Layer made of ion exchange resin

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Daizo Takaoka             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. F term (reference) 5H026 AA06 BB00 BB04 CX05 EE11                       EE12

Claims (5)

[Claims] 1. A fuel cell unit having a cell structure in which a catalyst layer and a gas diffusion layer are arranged in this order on both sides of a main surface of an electrolyte layer, wherein the electrolyte layer is made of a proton conductive gel, and the inside of the catalyst layer is formed. Alternatively, the fuel cell unit, wherein a layer made of an ion exchange resin is present at least at a part in contact with the catalyst layer. 2. The proton conductive gel is SiO₂ ,
Al₂ O₃ , TiO ₂ , V₂ O_Five , ZrO₂ Select from
Whether the material is exposed to phosphoric acid, perchloric acid, boric acid or silicic acid
A material selected from the group consisting of:
1. The fuel cell unit according to 1. 3. When manufacturing a fuel cell unit having a cell structure in which a catalyst layer and a gas diffusion layer are arranged in this order on both sides of a main surface of an electrolyte layer, at least a part of the inside of the catalyst layer or in contact with the catalyst layer A method for producing a fuel cell unit, comprising forming an electrolyte layer made of a proton conductive gel in a state where a layer made of an ion exchange resin is provided on the. 4. When manufacturing a fuel cell unit having a cell structure in which a catalyst layer and a gas diffusion layer are arranged in this order on both sides of a main surface of an electrolyte layer, at least a part of the inside of the catalyst layer or in contact with the catalyst layer. A method for producing a fuel cell unit, comprising forming an electrolyte layer made of a proton conductive gel in a state where a layer made of an ion exchange resin is provided, and then removing the layer made of the ion exchange resin. 5. The proton conductive gel is SiO 2.₂ ,
Al₂ O₃ , TiO ₂ , V₂ O_Five , ZrO₂ Select from
Whether the material is exposed to phosphoric acid, perchloric acid, boric acid or silicic acid
A material selected from the group consisting of:
3 or manufacturing the fuel cell unit according to claim 4.
Law.