JP2003203640A - Manufacturing method of porous gas diffusion electrode for fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a porous gas diffusion electrode for a fuel cell in which the sealing quality at the end part of the porous base body is improved and which can be applied to from low volume production to mass production. <P>SOLUTION: In the manufacturing method, a first process of thermo- compression bonding of a first synthetic resin sheet on the side face and the top and bottom faces of the end part that are in parallel with the reaction gas supply channel of the porous gas diffusion electrode of a fuel cell is implemented, and when a second process, in which a second and a third synthetic resin sheets are thermo-compression bonded on both top and bottom faces of the porous gas diffusion electrode clipped by two parallel heating pressure members and the first to the third synthetic resin sheets are infiltrated into the above porous gas diffusion electrode and absorbed, is implemented, a third process of forming the end part side face of the porous gas diffusion electrode is implemented. Thereby, the top and bottom faces of the end part and the side face of the end part of the porous gas diffusion electrode are made a smooth shape. <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, and more particularly to a method for manufacturing a porous gas diffusion electrode for a fuel cell.

[0002]

2. Description of the Prior Art FIG. 8 shows, for example, Japanese Patent Laid-Open No. 59-205164.
FIG. 3 is a perspective view of a unit cell including a porous gas diffusion electrode having a seal formed at an end portion disclosed in Japanese Patent Laid-Open Publication No. 2004-242242. In FIG. 8, 1
Is a single cell, and is composed of a matrix 2 holding an electrolyte, a fuel electrode 3, an oxidant electrode 4, a porous gas diffusion electrode 6 having a gas supply groove 5, and a gas separation plate 7 for separating the gas. There is. Fuel cell stack is a unit cell 1
Is formed by laminating a plurality of sheets. The gas supply groove 5 provided in each porous gas diffusion electrode 6 is laminated so that the directions thereof intersect with other reaction gas supply grooves provided above or below it. Therefore, in order not to mix the respective reaction gases with each other, the end side surfaces of the porous gas diffusion electrode 6 parallel to the respective reaction gas supply grooves are sealed so as not to mix the gases, and some electrical insulation is maintained. Treatment is being applied. As a sealing method, a synthetic resin film is pressure-bonded and thermocompression-bonded.
For example, JP-A-59-205164 and JP-A-11
9 and 10 show a manufacturing method showing the conventional end sealing method disclosed in Japanese Patent Publication No. 329454. In each of these figures, 8 is a porous substrate forming the porous gas diffusion electrode 6, 9a is a synthetic resin sheet made of, for example, a film of a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, and 9b is a porous substrate 8. 0. Crimped to the end
2 to 0.25 mm thick synthetic resin sheet,
Reference numerals 10a and 10b are synthetic resin sheets 9b which are pressure-bonded to both corners, which are partly overlapped with each other or which are thermocompression-bonded by abutting the end faces of the sheets with a thickness of about 0.1 to 0.15 mm. Is a press with a heating mechanism, 12 is, for example, a fluorine oil release agent, 13 is a male mold, 1
4 is a female die.

Next, the operation will be described. Fuel gas and oxidant gas are respectively supplied to the entire surfaces of the fuel electrode 3 and the oxidant electrode 4 from the gas supply grooves 5 formed in the porous gas diffusion electrode 6 so as to be orthogonal to each other, and pass through the matrix 2 impregnated with the electrolyte. React to obtain electrical energy. When the fuel gas and the oxidant gas are mixed, these reactants do not participate in power generation and not only the voltage drops, but also
The temperature in the fuel cell stack becomes high either locally or locally. As a result, deterioration of the catalysts of the fuel electrode 3 and the oxidant electrode 4, corrosion of the gas separation plate 7 and the porous gas diffusion electrode 6 are promoted, and the life of the fuel cell stack is shortened. Therefore, some measures are taken to prevent the gases from mixing and to seal the side surfaces of the end portions of the porous gas diffusion electrodes 6 parallel to the gas supply grooves so that the reaction gases do not mix with each other, and to maintain electrical insulation. It has been subjected. In FIG. 9, a synthetic resin sheet 9a made of a film-shaped copolymer having a thickness of 0.1 mm to 0.2 mm is put on the end surface of the porous substrate 8 in a U-shaped cross section, and the sheet is preliminarily coated with fluorine. Oil release agent 12
A treatment for thermocompression bonding from the directions of arrows A and B is performed by the male mold 13 to which is applied. (Hereinafter, referred to as known technology 1) In FIG.
Synthetic resin sheets 10a and 10b which are slightly thinner than 15 mm
Is processed into a predetermined width and length in advance, and the press with heating mechanism 1
A synthetic resin sheet 10b, a synthetic resin sheet 9b and a porous substrate 8 on which a synthetic resin sheet 9b has been pressure-bonded in a U shape, a synthetic resin sheet 10a, and a gas separation plate 7 are stacked in this order from the bottom,
After alignment, presses 11a and 11b with heating mechanism
The process of thermocompression bonding is performed. (Hereinafter referred to as publicly known technique 2)

[0004]

However, in the above-mentioned conventional known technique 1, when thermocompression bonding is performed, the size of the mold needs to be equal to or larger than the size of the porous substrate 8, and the porous substrate 8 is laterally arranged. Equipment for pressurizing the end face is also required, large equipment is required, and maintenance is difficult. Further, when one sheet of synthetic resin sheet 9a is crimped by a U-shaped molding die using the female die 14 and the male die 13, the synthetic resin sheet 9a is made of synthetic resin in the gap between the female die 14 and the male die 13. The sheet 9a flows in and burrs are generated in the vertical direction. When the cells are stacked, this burr may make the stacking difficult, and the adhesion between the cells may be impaired to deteriorate the sealing property. In addition, it is configured to seal with the film of one synthetic resin sheet 9a, and since the synthetic resin sheet 9a is made of a thin material of 0.1 mm, the seal is broken during thermocompression bonding, It may lead to poor sealing.

Further, in the prior art 2, when the thermocompression bonding is completed, the synthetic resin sheet 9a and the synthetic resin sheet 10 are impregnated into and absorbed by the porous substrate 8, so that the front and back surfaces of the porous substrate 8 are absorbed. Becomes flat. However, since there is no mold on the side surface of the end of the porous substrate 8, the melting state of the synthetic resin sheet 9b varies depending on the molding conditions such as temperature and pressure, and the moldability is not uniform, and the synthetic resin sheet 9b is not formed. If the cross-sectional shape is a good shape with a convex roundness on the outside, the sealability is good, but it is possible that a defective seal will occur on the side surface, such as the shape of 3 or the inclusion of bubbles inside. It will be expensive. Further, similar defects may occur at the four corners.

The present invention has been made to solve the above problems, and provides a manufacturing method capable of improving the quality of the end seal of the porous substrate and manufacturing a product of stable quality even in mass production. The purpose is to simplify the manufacturing equipment and reduce the capital investment cost.

[0007]

According to a first aspect of the present invention, there is provided a method of manufacturing a porous gas diffusion electrode for a fuel cell, wherein a side surface of an end portion of the porous gas diffusion electrode of the fuel cell parallel to a reaction gas supply passage. And the first step of thermocompressing the first synthetic resin sheet on the front and back surfaces is performed, and the second and third synthetic resin sheets are sandwiched between two parallel heat press members on each of the front and back surfaces of the porous gas diffusion electrode. When performing the second step of thermocompression bonding with, and impregnating and absorbing the first to third synthetic resin sheets into the porous gas diffusion electrode, the third side surface for molding the end side surface of the porous gas diffusion electrode is formed. By performing the steps at the same time, the front and back surfaces of the end portion and the side surfaces of the end portion of the porous gas diffusion electrode have a smooth shape.

According to a second aspect of the present invention, in the method for producing a porous gas diffusion electrode for a fuel cell, in the third step,
The end face of the porous base material is pressed from the side surface by the pressing means.

According to a third aspect of the present invention, there is provided a method for producing a porous gas diffusion electrode for a fuel cell, wherein the porous gas diffusion electrode of the fuel cell has a first side surface and a front and back surface parallel to a reaction gas supply channel. The first step of thermocompression bonding the synthetic resin sheet of No. 2 is performed, and the second and third synthetic resin sheets are sandwiched between two parallel heat press members on each of the front and back of the porous gas diffusion electrode, and thermocompression bonding is performed. When the second step of impregnating and absorbing the first to third synthetic resin sheets in the porous gas diffusion electrode is performed, the step of molding the corner portion of the porous gas diffusion electrode is performed to thereby diffuse the porous gas. The corners of the electrodes are smooth.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view illustrating a step of pressure-bonding a synthetic resin sheet and molding an end side surface of a porous gas diffusion electrode according to Example 1 of the first embodiment. In FIG. 1, 7 is a gas separation plate, 8 is a porous substrate, 9b is a slightly thick synthetic resin sheet crimped to the end side surface of the porous substrate 8, and 10a and 10b are a part of the synthetic resin sheet 9b. Sheets made of synthetic resin, which are slightly thinner, which are superposed on each other or brought into contact with the end faces of the sheets and thermocompression-bonded to the upper and lower surfaces of the end of the porous substrate 8, 11a and 11b are presses with a heating mechanism arranged above and below the porous substrate 8, and 12 is fluorine. It is an oil release agent and is composed of a release film such as a fluororesin film or a polyimide film. Reference numeral 15 denotes a side surface-forming metal lateral push plate disposed on the side surface of the porous substrate 8, which may or may not have a heating mechanism. The fluorine oil release agent 12 is made of synthetic resin sheets 9b, 10a, 10
b, the presses 11a and 11b, and the lateral push plate 15 are laid so as not to be pressure-bonded.

Next, the operation will be described. The synthetic resin sheet 9b is thermocompression bonded to the end side surface of the porous substrate 8 and the synthetic resin sheets 10a and 10b are partially overlapped with the synthetic resin sheet 9b, or the end surfaces of the sheets are butted against each other and the spot thermocompression bonding is applied. Fluorine oil release agent 1 which is a release film on the upper and lower surfaces of which the substrate 8 and the gas separation plate 7 are temporarily adhered
2 is spread and set in the presses 11a and 11b with a heating mechanism. The lateral push plate 15 is covered with a release agent for fluorine oil 12, which is a release film, and the synthetic resin sheet 9b is covered with the porous substrate 8.
Set to press against. In this state, the presses 11a and 11b with a heating mechanism are heated to a temperature of 280 to 300 ° C and then pressurized at 10 to 15 kg / cm2. If the horizontal push plate 15 has a heating mechanism, it is heated in the same manner. After pressurizing, the temperature is maintained for 10 to 30 minutes, and then the heater is turned off to cool. Then, it is disassembled when the temperature has dropped to 200 ° C or lower.

As described above, when the thermocompression bonding is completed, the synthetic resin sheets 9b, 10a, 10b are impregnated into and absorbed by the porous substrate 8, and the front and back surfaces of the porous substrate 8 become smooth.
The gas separating plate 7 and the porous substrate 8 are pressure-bonded to each other to form an interface seal. The synthetic resin sheet 9b is also pushed by the lateral pushing plate 15 on the side surface of the end face of the porous substrate 8 and is pressed against the porous substrate 8 to form a seal. Since the cross-sectional shape is pushed by the lateral push plate 15, the moldability is good, and it is possible to produce a smooth and uniform product without forming three characters depending on the molding conditions and without defects on the side surface such as entraining bubbles inside. . Further, since burrs are also generated in the lateral direction, the burrs do not cause difficulty in stacking when cells are stacked. By performing the third step of molding the end portions of the multi-element electrode in this manner, the side surfaces of the end portions of the multi-element electrode are made into a smooth shape, thereby eliminating defects on the end side surfaces and improving the productivity of the fuel cell. And the requestability can be improved.

Next, Example 2 of Embodiment 1 of the present invention
Will be described with reference to the drawings. FIG. 2 is a cross-sectional view for explaining the steps of pressure-bonding a synthetic resin sheet of a porous gas diffusion electrode and molding the end side surface according to the second embodiment. In FIG. 2, 7
Is a gas separation plate, 8 is a porous substrate, 9b is a slightly thick synthetic resin sheet which is pressure-bonded to the end side surface of the porous substrate 8, 1
0a and 10b are slightly thin synthetic resin sheets 11a, which are partially overlapped with the synthetic resin sheet 9b or whose sheet end faces are butted and thermocompression-bonded to the upper and lower surfaces of the end of the porous substrate 8.
Reference numeral 11b is a press with a heating mechanism disposed above and below the porous substrate 8, and 12 is a fluorine oil release agent, which is a release film such as a fluororesin film or a polyimide film. 16a and 16b are carbon plates sandwiching the porous substrate 8 and the gas separation plate 7 from above and below, and 17 is a side-molding carbon lateral pushing plate disposed on the side surface of the porous substrate 8 with or without a heating mechanism. May be. The fluorine oil release agent 12 is made of synthetic resin sheets 9b, 10a, 10
b, the carbon plates 16a and 16b, and the lateral push plate 17 are laid so as not to be pressure-bonded.

Next, the operation will be described. The synthetic resin sheet 9b is thermocompression-bonded to the end side surface of the porous substrate 8, the synthetic resin sheets 10a and 10b are partially overlapped with the synthetic resin sheet 9b, or the sheet end surfaces are butted against each other, and the spot thermocompression bonding is performed. Carbon plates 16a, 16 on which a high-quality substrate 8 and a gas separation plate 7 are temporarily bonded
It is sandwiched between b, a fluorine oil release agent 12 which is a release film is spread, and it is set in the presses 11a and 11b with a heating mechanism. Also on the side surface of the porous substrate 8, the side surface molding carbon lateral pressing plate 17 is covered with a fluorine oil releasing agent 12 which is a release film, and the synthetic resin sheet 9b is pressed against the porous substrate 8. In this state, the presses 11a and 11b with a heating mechanism are heated to a temperature of 280 to 300 ° C and then pressurized at 10 to 15 kg / cm2. Also,
When the horizontal push plate 17 is provided with a heating mechanism, it is heated in the same manner. After pressurizing, the temperature is maintained for 10 to 30 minutes, and then the heater is turned off to cool. Then, it is disassembled when the temperature has dropped to 200 ° C or lower.

For example, when the product size is 1 m and SUS is used for the lateral push plate, if the temperature is raised to 300 ° C.,
Compared to room temperature, SUS stretches about 5 mm, the carbon material stretches about 0.6 mm, and the difference in thermal stretch between them is about 4 mm. Due to the difference in thermal expansion, wrinkles may occur in the synthetic resin sheets on the front and back surfaces and the side surfaces, which may cause problems. However, as described above, by using carbon for the vertical pressing of the porous gas diffusion electrode and the horizontal pressing plate, the difference in thermal expansion is reduced, and it is possible to manufacture a product with less defects and high reliability. As described above, by using the carbon material for the upper and lower surfaces of the porous gas diffusion electrode and the lateral push plate, it is possible to improve the productivity and reliability of the fuel cell.

Embodiment 2. Embodiment 2 of the present invention will be described below with reference to the drawings. FIG. 3 is a cross-sectional view illustrating a step of pressure-bonding a synthetic resin sheet of a porous gas diffusion electrode and molding an end side surface according to Example 1 of Embodiment 2 of the present invention. In FIG. 3, 7 is a gas separation plate, 8 is a porous substrate, 9b is a slightly thick synthetic resin sheet crimped onto the end side surface of the porous substrate 8, and 10a and 10b are a part of the synthetic resin sheet 9b. Sheets made of synthetic resin, which are slightly thinner, which are superposed on each other or brought into contact with the end faces of the sheets and thermocompression-bonded to the upper and lower surfaces of the end of the porous substrate 8, 11a and 11b are presses with a heating mechanism arranged above and below the porous substrate 8, and 12 is fluorine. It is an oil release agent and is composed of a release film such as a fluororesin film or a polyimide film. Reference numeral 15 denotes a side surface-forming metal lateral push plate disposed on the side surface of the porous substrate 8, which may or may not have a heating mechanism. The fluorine oil release agent 12 is made of synthetic resin sheets 9b, 10a, 10b.
The presses 11a and 11b and the horizontal push plate 15 are laid so as not to be pressure-bonded. Reference numeral 18 denotes a pressing means including a spring or the like for pressing the synthetic resin sheet 9b against the porous base body 8 by the lateral push plate 15 to press it, and a stopper 19
It is fixed at.

Next, the operation will be described. A synthetic resin sheet 1 is formed by thermocompression bonding the synthetic resin sheet 9b to the end side surface.
0a and 10b are partially overlapped with the synthetic resin sheet 9b, or the porous substrate 8 and the gas separation plate 7 which have been thermocompression-spotted with the end faces of the sheets butted against each other are temporarily adhered to each other. The oil release agent 12 is spread and set on the pressure bonding presses 11a and 11b with a heating mechanism. The lateral push plate 13 is covered with a release agent for fluorine oil 12, which is a release film, and the synthetic resin sheet 9b is set so as to be pressed against the porous substrate 8. A pressurizing means 18 composed of a spring or the like is inserted between the stopper 19 and the lateral push plate 15, and the synthetic resin sheet 9b is pressed against the porous substrate 8. In this state, the presses 11a and 11b with a heating mechanism are heated to 280-3.
After the temperature rises to 00 ° C, pressure is applied at 10 to 15 kg / cm2. If the horizontal push plate 15 has a heating mechanism, it is heated in the same manner. After pressurizing, the temperature is maintained for 10 to 30 minutes, and then the heater is turned off to cool. And 200
Dismantle when the temperature drops below ° C.

In this way, by pressing the lateral push plate 15 with the pressing means 18 such as a spring, the synthetic resin sheet 9b can be uniformly pressed onto the porous substrate 8 over the entire surface, and a highly reliable one can be obtained. Can be manufactured. Further, as shown in FIG. 9, since it is not fixed, the porous substrate 8 and the like can be easily set and is not affected by thermal elongation or the like. And since a spring is used as the pressurizing means 18,
Large equipment for pressurizing from the side is not required, and the apparatus can be simplified. In this way, the horizontal pushing plate 15
By pressing with the pressurizing means 18 such as a spring, the productivity and the requestability of the fuel cell can be improved, the apparatus can be simplified, and the facility investment cost and the maintenance cost can be reduced.

Next, Example 2 of Embodiment 2 of the present invention
Will be described with reference to the drawings. FIG. 4 shows a second embodiment of the present invention.
FIG. 6 is a perspective view illustrating a step of pressure-bonding a synthetic resin sheet and molding an end side surface of the porous gas diffusion electrode according to Example 2 of FIG. In FIG. 4, 8 is a porous substrate, 9b is a slightly thick synthetic resin sheet that is pressure-bonded to the end side surface of the porous substrate 8, and 10a and 10b are partially overlapped with the synthetic resin sheet 9b or the sheet end surface is A slightly thin synthetic resin sheet which is butted and thermocompressed to the upper and lower surfaces of the end of the porous substrate 8, 1
5 is a lateral push plate arranged on the side surface of the porous substrate 8,
It may or may not have a heating mechanism. 20 is a horizontal push plate 15
In order to press the synthetic resin sheet 9b against the porous substrate 8 for pressure bonding, the pressure means is made of, for example, an arc-shaped spring material, and is fixed by a stopper 19.

Next, the operation will be described. The porous substrate 8 has a thickness of about 2 to 5 mm and is very thin. Further, since the presses 11a and 11b also overhang more than the porous substrate 8, the lateral push plate 15 needs to have the same thickness as the porous substrate 8 or thinner. When a spring spring is used, the outer diameter of the spring is as small as 2 to 5 mm, the spring easily falls, becomes unstable, and sufficient pressing force cannot be obtained. Therefore, as in Example 2 of Embodiment 2 of the present invention, by using the pressurizing means 20 formed of a spring material formed in an arc shape, a sufficient pressing force can be obtained even if the spring material has a small linear shape. can get. Also, the stability is good, the spring material does not fall down, the entire surface can be pressed uniformly, a more reliable product can be manufactured, and the cost can be reduced. As described above, by using the pressurizing means 20 composed of the spring material formed into the arc shape, it is possible to improve the productivity and reliability of the fuel cell and reduce the device cost.

Embodiment 3. Embodiment 3 of the present invention will be described below with reference to the drawings. FIG. 5 is a plan view illustrating steps of pressure-bonding a synthetic resin sheet of a porous gas diffusion electrode and molding end side surfaces and corner portions according to Example 1 of Embodiment 3 of the present invention. In FIG. 5, 8 is a porous substrate, 9b is a slightly thick synthetic resin sheet crimped onto the end side surface of the porous substrate 8, and 10a is a synthetic resin sheet 9b.
A sheet of synthetic resin that is slightly thin and is partially overlapped with the sheet, or the end faces of the sheets are butted against each other and thermocompression-bonded to the upper surface of the end of the porous substrate 8. Reference numeral 15 is a lateral pressing plate for side surface molding disposed on the side surface of the porous substrate 8. Yes, with or without a heating mechanism.
Reference numeral 21 denotes a pressing plate for molding the corner portion of the porous substrate 8, which is fixed by a stopper 22.

Next, the operation will be described. The synthetic resin sheets 9b and 10a are thermocompression-bonded to the end surface and the front and back surfaces of the porous substrate 8, and the lateral pressing plate 15 is set. As for the corner part, the push plate 21 for molding the corner part is 4
Set at each corner of the corner and fix with the stopper 22. After heating in this state and raising the temperature to 280 to 300 ° C., pressure is applied at 10 to 15 kg / cm 2. After maintaining the temperature for 10 to 30 minutes, the heater is turned off to cool. Then, it is disassembled when the temperature has dropped to 200 ° C. or lower.

As described above, by pushing the corner portions as well as the side portions by the push plate 21 for molding the corner portions, the synthetic resin sheet 9b can be evenly pressure-bonded to the porous substrate 8. It is possible to manufacture high quality products. As described above, the corner portion is pushed by the push plate 21 for molding the corner portion, like the side surface portion, so that the productivity and the reliability of the fuel cell can be improved.

Next, Example 2 of Embodiment 3 of the present invention
Will be described with reference to the drawings. FIG. 6 shows a third embodiment of the present invention.
FIG. 6 is a plan view illustrating a step of pressure-bonding a synthetic resin sheet and molding end side surfaces and corner portions of the porous gas diffusion electrode according to Example 2 of FIG. In FIG. 6, 8 is a porous substrate, 9b is a slightly thick synthetic resin sheet crimped onto the end side surface of the porous substrate 8, and 10a and 10b are either partially overlapped with the synthetic resin sheet 9b or the sheet end face is A slightly thin synthetic resin sheet that is butted and thermocompression-bonded to the upper surface of the end of the porous substrate 8. Reference numeral 15 is a lateral molding lateral pressing plate disposed on the side surface of the porous substrate 8 and extends to the corner portion. Reference numeral 23 denotes a push plate for molding the corner portion of the porous substrate 8, which is fixed by a horizontal push plate 15 extended to the corner portion.

In this way, as in the case of the side portions, the corner portion is pressed uniformly by pressing the pushing plate 23 for molding the corner portion with the lateral pushing plate 15 so that the synthetic resin sheet 9b is uniformly pressed onto the porous substrate 8. In addition, the stopper 22 can be omitted. Further, even when the pushing mechanism is provided, the corner portion can be pushed with a uniform force against the side portion. In this way, by pushing with the pushing plate 23 for molding the corner portion with the lateral pushing plate 15, it is possible to improve the productivity and reliability of the fuel cell.

Next, Example 3 of Embodiment 3 of the present invention
Will be described with reference to the drawings. FIG. 7 shows a third embodiment of the present invention.
FIG. 6 is a plan view illustrating a step of pressure-bonding a synthetic resin sheet and molding end side surfaces and corner portions of the porous gas diffusion electrode according to Example 3 of FIG. In FIG. 7, 8 is a porous substrate, 9b is a slightly thick synthetic resin sheet that is pressure-bonded to the end side surface of the porous substrate 8, and 10a and 10b are partially overlapped with the synthetic resin sheet 9b or the sheet end surface is A slightly thin synthetic resin sheet that is butted and thermocompressed to the upper surface of the end of the porous substrate 8, and 15 is a lateral pressing plate for side surface formation, which is arranged on the side surface of the porous substrate 8. Reference numeral 24 is a pressing plate for molding the corner portions of the porous substrate 8 and is made of the same material as the synthetic resin sheets 9b, 10a, 10b.

As described above, the push plate 24 for molding the corner portion is provided with the synthetic resin sheets 9b, 10a, 10b.
By using the same material as above, the pressing plate 24 is pressure-bonded to the synthetic resin end portion 1a and thermocompression-bonded to the other corner portion 1h sequentially. The sheets 9b, 10a and 10b are melted and integrated. This improves the reliability of the corner portion. By thus forming the push plate 24 for molding the corner portion with the same material as the synthetic resin sheets 9b, 10a, 10b, the reliability of the fuel cell can be improved.

[0028]

According to the first aspect of the present invention, the first synthetic resin sheet is thermocompression bonded to the side surface and the front and back surfaces of the end portion of the porous gas diffusion electrode of the fuel cell which is parallel to the reaction gas supply channel. The first step is performed, and the second and third synthetic resin sheets are sandwiched between two parallel heating press members on each of the front and back sides of the porous gas diffusion electrode, and thermocompression-bonded to each other. When the second step of impregnating and absorbing the porous gas diffusion electrode is performed, by simultaneously performing the third step of molding the end side surface of the porous gas diffusion electrode, the end of the porous gas diffusion electrode By making the front and back surfaces of the parts and the side surfaces of the ends smooth, it is possible to eliminate defects on the side surfaces of the ends and improve the productivity and reliability of the fuel cell.

According to the second aspect of the present invention, in the third step, the end face of the porous base material is pressed from the side surface by the pressurizing means, thereby improving the productivity and reliability of the fuel cell. It can be improved and the device cost can be reduced.

According to the third aspect of the present invention, the first synthetic resin sheet is thermocompression bonded to the side surface and the front and back surfaces of the end portion of the porous gas diffusion electrode of the fuel cell which is parallel to the reaction gas supply passage. The first step is performed, and the second and third synthetic resin sheets are sandwiched between two parallel heating press members on each of the front and back sides of the porous gas diffusion electrode, and thermocompression-bonded to each other. When the second step of impregnating and absorbing the porous gas diffusion electrode is carried out, the corner of the porous gas diffusion electrode is formed into a smooth shape by performing the step of molding the corner of the porous gas diffusion electrode. By doing,
The productivity and reliability of the fuel cell can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view illustrating a pressure bonding step of a synthetic resin sheet for a porous gas diffusion electrode of a fuel cell according to Example 1 of Embodiment 1 of the present invention.

FIG. 2 is a diagram illustrating a pressure bonding step of a synthetic resin sheet for a porous gas diffusion electrode of a fuel cell in Example 2 of Embodiment 1 of the present invention.

FIG. 3 is a diagram illustrating a pressure bonding step of a synthetic resin sheet for a porous gas diffusion electrode of a fuel cell in Example 1 of Embodiment 2 of the present invention.

FIG. 4 is a diagram illustrating a pressure bonding step of a synthetic resin sheet for a porous gas diffusion electrode of a fuel cell in Example 2 of Embodiment 2 of the present invention.

FIG. 5 is a diagram illustrating a pressure bonding step of a synthetic resin sheet for a porous gas diffusion electrode of a fuel cell according to Example 1 of Embodiment 3 of the present invention.

FIG. 6 is a diagram illustrating a pressure bonding step of a synthetic resin sheet for a porous gas diffusion electrode of a fuel cell in Example 2 of Embodiment 3 of the present invention.

FIG. 7 is a diagram illustrating a pressure bonding step of a synthetic resin sheet for a porous gas diffusion electrode of a fuel cell in Example 3 of Embodiment 3 of the present invention.

FIG. 8 is a perspective view showing a configuration of a unit cell including a porous gas diffusion electrode of a conventional fuel cell.

FIG. 9 is a diagram illustrating a pressure bonding step of a synthetic resin sheet for a porous gas diffusion electrode of a conventional fuel cell.

FIG. 10 is a diagram illustrating a pressure bonding step of a synthetic resin sheet for a porous gas diffusion electrode of another conventional fuel cell.

[Explanation of symbols]

5 gas supply groove, 6 porous gas diffusion electrode, 8 porous substrate, 9a synthetic resin sheet, 9b synthetic resin sheet, 10a synthetic resin sheet, 10b synthetic resin sheet, 11a press, 11b press, 15 horizontal Push plate, 16a carbon plate, 16b carbon plate, 17 horizontal push plate, 18 spring, 20 spring material, 21 push plate, 23 push plate, 24 corner push plate.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshinobu Higashijima             2-3 2-3 Marunouchi, Chiyoda-ku, Tokyo             Inside Ryo Electric Co., Ltd. (72) Inventor Yoshito Yamada             2-3 2-3 Marunouchi, Chiyoda-ku, Tokyo             Inside Ryo Electric Co., Ltd. F-term (reference) 5H018 AA06 AS01 BB03 BB05 BB09                       CC06 DD08 EE17

Claims (3)

[Claims] 1. A first step of thermocompression bonding a first synthetic resin sheet to the side surface and front and back surfaces of an end portion of a porous gas diffusion electrode of a fuel cell, which is parallel to a reaction gas supply flow path, to obtain the above-mentioned porous material. The second and third synthetic resin sheets are sandwiched between two parallel heating press members on each of the front and back sides of the gas diffusion electrode and thermocompression-bonded, and the first to third synthetic resin sheets are applied to the porous gas diffusion electrode. A third step of molding the end side surface of the porous gas diffusion electrode when performing the second step of impregnating and absorbing
The method for producing a porous gas diffusion electrode for a fuel cell, wherein the front and back surfaces of the end portion and the side surfaces of the end portion of the porous gas diffusion electrode are made into a smooth shape by simultaneously performing the above step. 2. The method for producing a porous gas diffusion electrode for a fuel cell according to claim 1, wherein in the third step, the end face of the porous base material is pressed from the side surface by the pressing means. 3. The first step of thermocompressing a first synthetic resin sheet on the side surface and front and back surfaces of an end portion of a porous gas diffusion electrode of a fuel cell which is parallel to a reaction gas supply flow path, and the porous material The second and third synthetic resin sheets are sandwiched between two parallel heating press members on each of the front and back sides of the gas diffusion electrode and thermocompression-bonded, and the first to third synthetic resin sheets are applied to the porous gas diffusion electrode. When the second step of impregnating and absorbing is performed, a step of molding the corner portion of the porous gas diffusion electrode is performed to form the corner portion of the porous gas diffusion electrode into a smooth shape. And a method for producing a porous gas diffusion electrode for a fuel cell.