JPS6119069A - Electrode substrate for fuel cell and its manufacture - Google Patents

Abstract

PURPOSE:To obtain an electrode substrate for fuel cell having long life and high mechanical strength by forming an electrode substrate in three layer structure which is formed by bonding together two porous carbon layers on both sides of a separator. CONSTITUTION:A separator10 comprises a gas separating part 11 and a gas leakage prevention edge 12 bonded together by burning. The porous carbon layer of electrode substrate 1 is fitted to each side of the separator 11 and fixed betweeen a pair of the gas leakage prevention edge 12. Holes 4 which serve as reaction gas passage are installed in the middle part of a direction of thickness of the substrate 1. The porous carbon layer consists of two layers having different density, and a layer 3 located on the separator side from the hole 4 has higher density compared with a layer 4 located on the electrode side. By using the separator 10, the electrode substrate having long life and high mechanical strength is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electrode substrate for a fuel cell and a method for manufacturing the same, and more particularly, the present invention relates to an electrode substrate for a fuel cell and a method for manufacturing the same. The present invention relates to a fuel cell electrode substrate integrated as carbon and a method for manufacturing the same.

(Prior Art) Various types -b have been proposed as electrode substrates for fuel cells.

Conventionally proposed monopolar fuel cells are constructed by stacking an electrode substrate with ribs on one side and a flat structure on the other, a catalyst layer, a matrix impregnated with electrolyte, and a separator sheet. The reaction gas (oxygen or hydrogen) diffuses from the ribbed surface of the electrode substrate onto the flat electrode surface.

On the other hand, conventional methods for manufacturing electrode substrates for monopolar fuel cells include a press molding method using short carbon fibers as a base (Japanese Patent Publication No. 58-117649), a paper-making method that avoids dispersion of carbon fibers (Japanese Patent Publication No. 53-18603). ), a method has been proposed (US Pat. No. 3,829,327) of chemically vapor depositing pyrolytic carbon onto a web of carbon mn. The electrode substrates obtained by these conventional manufacturing methods all consist of a single layer with an entirely homogeneous structure.

When such a homogeneous single-layer electrode substrate has a large bulk density, the gas diffusion coefficient is small, so the limiting current density is small, and the electrolyte retention amount is not sufficient, so the performance deteriorates earlier. In other words, it has the disadvantage of a short lifespan. On the other hand, when the bulk density is low, it has the drawbacks of high electrical resistance, high thermal resistance, and low mechanical strength such as bending strength.

Further, the fuel cell separator has the function of isolating each reaction gas from each other and at the same time serving as a connecting conductor between unit cells. Therefore, fuel cell separators have low gas permeation, low thermal and electrical resistance, and
Particularly when the battery area is large, characteristics such as high mechanical strength, such as high bending strength, are required.

However, in conventional monopolar fuel cells, when stacking a porous electrode substrate and a separator as a gas diffusion part,
There is a drawback that the electrical and thermal contact resistance between the electrode substrate and the separator becomes unreasonably large. It is generally said that such contact resistance is several times as large as the transmission resistance within the substrate, and non-uniformity of temperature distribution between cells may lead to a decrease in power generation efficiency.

In Japanese Patent Application Laid-Open No. 59-68170, the present inventors have disclosed that a fuel cell is integrated with a porous bamboo carbonaceous layer as a gas diffusion layer on both sides of a dense carbonaceous layer that functions as a separator. Provided an electrode substrate for batteries. In this electrode substrate, the above-mentioned contact resistance was completely eliminated, and thermal and electrical conductivity were greatly improved.

On the other hand, in fuel cells, reaction gas also diffuses to the side surfaces of the porous substrate, so in order to prevent this, the edges of the substrate are usually impregnated with a fluorine-based resin, and/or the surroundings are Use a sealing member.

In recent years, separators that also serve as this peripheral sealing member have been developed.

For example, in Japanese Patent Application Laid-Open No. 58-214277, reaction gas supply grooves are formed in directions that intersect with each other over the entire surface, and a band-shaped elastic band having several rows of protrusions on both side edges that engage with the supply grooves is disclosed. A gas separator plate for a fuel cell is described in which the sealing surfaces are formed by joining the pieces together. In this gas separation plate (separator), the strip made of, for example, fluororubber or fluororesin molded material functions as a gas sealing material, but this strip is not carbonized integrally with the gas separation plate; Therefore, the thermal and electrical resistance of the sealing material portion increases.

Furthermore, Japanese Patent Application Laid-Open No. 58-12267 discloses a fuel cell that is integrally carbonized (having the same external shape as the above-mentioned gas separation plate with a band-like piece for sealing material, but without the reaction gas supply grooves). gas separation plates are described.

Both gas separator plates are made from a mixture of graphite powder and phenolic resin. For this reason, it was insufficient particularly in terms of gas permeability and mechanical strength (particularly bending strength).

The present inventors also wrote in Japanese Unexamined Patent Publication No. 59-96661,
The present invention provides an electrode substrate for a fuel cell comprising a graphite sheet for peripheral sealing that is integrated with a graphite sheet as a separator to prevent leakage of reaction gas to the side surface of the cell, and a porous carbonaceous layer as a gas diffusion part.

After that, further research was conducted to find that non-graphitizable carbonaceous particles such as fired crushed crystals of bitge oxide were used as a filler instead of graphite powder as disclosed in the above-mentioned Japanese Patent Application Laid-open No. 58-12267@. By carbonization firing, a fuel cell separator is obtained in which a peripheral sealing part that prevents leakage of reactant gas to the side of the cell and a separator part that substantially isolates reactant gas are integrated, and this separator has excellent mechanical properties. They discovered that it has strength and improved gas permeability, and completed the present invention.

(Problems to be solved by the invention) The present invention uses a fuel cell separator having superior mechanical strength, such as bending strength, excellent airtightness (low gas permeability), good thermal and electrical conductivity, etc. The main purpose is to improve the drawbacks of conventional electrode substrates for fuel cells.

(Structure of the Invention) The electrode substrate for a fuel cell of the present invention includes a porous carbonaceous layer as a gas diffusion layer, a separator, and the porous carbonaceous layer in this order, and the whole is fired and integrated as carbon. It has a three-layer structure.

The separator of the electrode substrate of the present invention consists of a gas isolation separator part that isolates the reaction gas of the counter electrode from each other, and a gas leakage prevention edge that prevents the reaction gas from leaking to the side of the battery, Preventing edges are opposed to each other with the gas isolation separator section in between, and each pair of the gas leakage prevention edges on both sides of the gas isolation separator section are orthogonal to each other, and the whole is carbonized and fired to be integrated. has been done.

Further, the porous carbonaceous layer is bonded to both sides of the gas isolation separator portion, and is fitted between the pair of gas leakage prevention edges, respectively, and has a reaction gas flow path approximately in the center of its thickness. The porous carbonaceous layer has a group of hollow holes, and the average bulk density of the porous carbonaceous layer on the side of the separator from the group of hollow holes is greater than the average bulk density of the porous carbonaceous layer on the side of the electrode surface from the group of hollow holes.

In addition, the method for manufacturing an electrode substrate for a fuel cell provided by the present invention includes short carbon fibers @ 100 parts by weight, binder resin by 20 parts,
A molded plate having a plurality of grooves for hollow holes is produced by heating and press-molding a mixture consisting of ~100 parts by weight and 0 to 100 parts by weight of a granular polymeric substance having a predetermined particle size distribution, and similarly, 100N parts of carbon fiber, 20 parts of binder resin
A flat plate is prepared by heating and press-molding a mixture consisting of ~100 parts by weight and 40 to 200 parts by weight of a granular polymeric substance having a predetermined particle size distribution, and the molded plate and the flat plate are sandwiched between the grooves. The two molded bodies for porous carbonaceous layers thus obtained are laminated in a mold and heated and press-molded again so as to fit between the gas leakage prevention edges of the separator part. It consists of joining using an adhesive, and then sintering and carbonizing the whole to integrate it.

(Explanation of Preferred Embodiments) The present invention will be described in detail below with reference to the accompanying FIGS. 1 and 2, but the present invention is not limited to these preferred embodiments.

As shown in FIG. 1, the electrode substrate 1 of the present invention has a three-layer laminated structure in which two porous carbonaceous layers 2 and 3 are integrally formed on both sides of a separator 10. There is.

As shown in FIG. 2, the separator 10 of the electrode substrate of the present invention includes a gas isolation separator portion 11 that functions to isolate the reaction gas of the counter electrode from each other, and a gas isolation separator portion 11 that serves to prevent the reaction gas from leaking toward the side of the cell. It consists of a gas leakage prevention edge 12 which performs the function of preventing gas leakage.

A pair of gas leak prevention edges 12 are provided at opposing peripheral parts with the gas isolation separator section 11 in between, and each pair of gas leak prevention edges 12 on the front and back surfaces of the gas isolation separator section 11 are orthogonal to each other. It is set up to do so. The electrode substrate separator 10 of the present invention is carbonized and fired and integrated.

The thickness of the gas isolation separator portion 11 of the separator 10 used in the present invention is sufficient to isolate the reaction gases from each other, and if it is too thick, it will be disadvantageous when stacked and used as a fuel cell. Generally this thickness is 1.5I
I1m or less.

The gas isolation separator section 11 of this separator has excellent airtightness, and has a gas permeability of 10-'7 ci/se.
c, cmHg or less, and the mechanical bullet holes are large, for example, the bending strength is 500 kQ/Cd or more, and further,
Excellent thermal and electrical conductivity, thermal conductivity is 4kcal
/ m, hr, 'C or more, electrical resistance is 10 raΩC
l11 or less.

The height of the gas leakage prevention edge 12 of the separator 10 (height from the surface of the gas isolation separator section 11) corresponds to the thickness of the porous carbonaceous layer (total thickness of 2 and 3 in Fig. 1). It is generally 2.5 +u or less. The gas permeability through which the reactive gas passes through the gas leakage prevention edge 12 toward the side of the battery is a sufficiently low value to prevent the reactive gas from leaking to the side of the battery, and is generally 10'.
c#f/sea, cmHa or less.

The separator 10 can be manufactured by the method described below, but the important thing is that the gas isolation separator part 11 and the gas leakage prevention edge part 12 are carbonized and fired into one body, and have the excellent physical properties as described above. That's what I'm doing.

As shown in FIG. 1, the porous carbonaceous layer of the electrode substrate of the present invention is bonded to both sides of the gas isolation separator section 11 and fitted between the pair of gas leakage prevention edges 12, respectively. ing. Moreover, a hollow hole group consisting of hollow holes 4 serving as a reaction gas flow path is provided approximately at the center of the thickness. This hollow hole path 4 is continuous from one end surface of the electrode substrate to the opposite end surface, and each hollow hole path 4 is approximately parallel to each other and approximately parallel to the electrode surface and the -side surface of the electrode substrate, and further Said gas interval 1lllll? The hollow holes 4 on both the front and back surfaces of the barreter part 11 have directions perpendicular to each other (see FIG. 1).

The cross-sectional shape of the hollow hole 4 may be arbitrary, for example, it may be rectangular as shown in FIG. 1, or it may be circular. When the cross-sectional area of the hollow hole channel 4 is converted into the cross-sectional area of a circle, the dimension corresponding to the diameter of the circle (referred to as the equivalent diameter) is 0.5 to 1.
5na+ is preferable, and if this equivalent diameter is smaller than 0.5IiIl, the electrode substrate area becomes large and the length of the hollow hole becomes long, and the gas flow resistance becomes too large.
If it is larger than 1.5IllIll, the porous carbonaceous layer on both sides of the hollow hole group becomes too thick, and the volumetric efficiency of the cell in which the electrode substrates are laminated decreases.

The porous carbonaceous layer of the electrode substrate 1 of the present invention is composed of two layers with different bulk densities. larger than the bulk density of the side (referred to as electrode surface side layer 2).

The average bulk density of the electrode surface side layer 2 is 0.4 to 0.8 (J/c
M, and the gas permeability is 2 (7/cn+, hr,
It is preferable that it is equal to or higher than mmAQ. Further, the porosity of the electrode surface side layer 2 is 50 to 80%, and the pores thereof are interaxial pores, and it is preferable that 60% or more of the pores have a diameter within the range of 10 to 100 μ.

The separator side layer 3 of the electrode substrate 1 of the present invention has a thickness of 0.5
~1. Preferably it has an average bulk density of Og/cIiI.

As described above, the porous carbonaceous layer of the electrode substrate 1 of the present invention is composed of the separator side layer 3 having a large bulk density and the electrode surface side layer 2 having a smaller bulk density. Only the electrode surface side layer 2 is formed. However, since these two layers are integrally carbonized and fired, the thermal and electrical resistance is good.

In addition, in the present invention, a graphite sheet (
(not shown), the reaction gas permeability is further reduced, and the stress caused by the difference in firing shrinkage between the old separator and the porous carbonaceous layer that occurs when the two parts are fired is alleviated. More favorable results are obtained.

The electrode substrate of the present invention is manufactured as follows.

The separator is manufactured as follows.

One preferred method of manufacturing the separators for use in the present invention is to separately preform the veneers for the gas isolation separator section and the veneer for the gas leakage prevention edges, and then mold them to the desired structure. Press molded in the mold and further 1
Burned and carbonized at a temperature of 000°C or higher.

The raw material used in this method is between 50 and 90% carbon filler.
, preferably 60-80% by weight and 10-50% binder.
% by weight, preferably from 20 to 40% by weight.

The carbon filler is particles with an average particle size of 40μ or less, preferably 10μ or less, selected from non-graphitizable carbonaceous particles such as fired and crushed oxide pitch products, crushed carbon fiber products, and fired products of phenol particles. A fired and crushed oxide pitch product produced by the method described in Publication No. 53-31116 can be preferably used. Incidentally, as the carbon filler, a mixture of two or more of the above-mentioned non-graphitizable carbonaceous particles can also be used.

As the binder used for producing the separator, phenolic resin is preferred.

The above mixture is fed into a mold having a predetermined shape and preformed to produce a thin plate for a gas isolation separator section or a single plate for a gas leakage prevention edge. Preforming conditions are temperature of 10~130℃, preferably ioo~120℃, 30~200 kg/c
tl, preferably 5 to 30 minutes at a pressure of 80 to 150 kQl eta.

The thin plates and veneers preformed in this manner are put into a mold having a predetermined shape to give a predetermined structure as shown in FIG. 2, for example, and press-molded. The press molding conditions are a temperature of 120 to 200°C, preferably 130 to 160°C, and a pressure of 30 to 200 k(J/ci, preferably 80 to 1
50 k (1/ci) for 10 to 20 minutes. After press molding, post-curing at a temperature of 130 to 160°C and a pressure of 0.5 kO/ci or less for at least 2 hours will give a preferable result. After that, a temperature of 1000°C or higher is obtained. An integrated separator can be obtained by carbonization firing at a high temperature.

Incidentally, the separator used in the present invention can also be integrally molded as follows. That is, the mixture is supplied to a mold of a predetermined shape (for example, giving a structure as shown in FIG. 2), press-molded under the conditions described above, preferably post-cured, and then carbonized and fired at a temperature of 1000° C. or higher. do.

Next, a porous carbonaceous layer is manufactured as follows.

First, as the separator side layer 3 of the porous carbonaceous layer,
A molded plate having a plurality of hollow holes and common grooves is manufactured as follows.

N100 short carbon fiber, 20 to 100 parts by weight of binder resin, and particulate polymeric material having a predetermined particle size distribution (III
(pore control material) 0 to 100 parts by weight are mixed. As the short carbon fiber navy blue, for example, as the carbon mH1 binder resin having an average fiber length of 1.0 mm or less and fired at 2000°C, fine fibers such as phenol resin with an average particle size of 100 μ or less and a carbonization yield of 30% by weight or more are used. As a pore control material, 70% or more of the particles are 3
Polyvinyl alcohol particles having a particle size of 0 to 300 microns and showing no volatilization or melt flow at at least 100° C. are preferably used. These monthly interest rates are disclosed in, for example, Japanese Patent Laid-Open No. 59-96661.

Next, the mixture obtained above is placed in a mold of a predetermined shape and molded under heat and pressure. The molding is done by press molding.

Press molding conditions are mold heating temperature 70~130℃, molding pressure 20~100 ko/ctnz pressure holding time 1~3
It is 0 minutes.

Next, a flat plate serving as the electrode surface side layer 2 of the porous carbonaceous layer is manufactured as follows.

Short carbon! Li navy blue 100 parts by weight, binder resin 20-100 parts
parts by weight and 40 to 200 parts by weight of a particulate polymeric substance (pore control material) having a predetermined particle size distribution are mixed. Each raw material is the same as above, and as the short carbon iIM, one having an average fiber length of 1.0 mn+ or less fired at 2000° C. is preferable.

Next, the obtained mixture is placed in a mold and molded under heat and pressure. Press molding conditions were the same as above.

The molded plate obtained as described above is placed in a predetermined mold with the groove facing upward, and then the flat plate is laminated on top of the molded plate, and the mold heating temperature is 130 to 160°C and the molding pressure is 20 to 100 k. <
1/cd and press molding with a pressure holding time of 1 to 60 minutes. At this time, more preferable results can be obtained if the graphite sheet is placed first, then the molded plate with the groove facing upward, and then the flat plate are placed in the mold in that order and integrally molded. In addition, after press molding, it is preferable to post-cure at the molding temperature for about 2 hours or more.

A phenolic adhesive is applied to the surface of the grooved molded plate (the graphite sheet surface if the graphite sheet is integrally molded) of the thus obtained molded body for porous carbonaceous layer, and the coated surface is turned upward. Place it in a mold, then supply a separator, and then supply the molded body with the adhesive coated side down into the mold.
Mold heating temperature 130-160℃, molding pressure 1-30kg/
Press molding is performed under the conditions of cd and pressure holding time of 5 to 60 minutes.

Thereafter, it is post-cured at the molding temperature for about 2 hours or more. 1 more
The electrode substrate of the present invention can be obtained by firing at a temperature of 000° C. or higher.

(Operations and Effects of the Invention) The fuel cell electrode substrate of the present invention obtained as described above has high mechanical strength, particularly bending strength, and excellent thermal and electrical conductivity. Furthermore, the sealing means conventionally required to prevent reaction gas from leaking to the side of the battery becomes unnecessary. At the same time, since the edges of the gas leakage prevention 1 are also integrally carbonized and fired, there is an effect that the thermal and electrical resistance is reduced. In addition, since the bulk density of the separator side layer of the porous carbonaceous layer is relatively high, the diffusion area for the reaction gas is essentially only the electrode side layer, which has the advantage that the thermal and electrical resistance of the entire substrate is reduced. is obtained.

(Example) The invention will now be illustrated by means of non-limiting examples.

・j伜1 (Manufacture of separator) Oxidized pitch manufactured by the method described in Japanese Patent Publication No. 53-31116 was fired at 800°C and crushed to have an average particle size of 1 μm or less.

65% by weight of the above calcined and crushed oxide pitch product and 35% by weight of phenol resin (RM-218, manufactured by Asahi Yukizai) were mixed using a blade mixer. This mixture was supplied to a mold of a predetermined shape and preformed at 120° C. and 100 kQ/cm to produce a thin plate for a gas isolation separator section.

In the same manner, a veneer for gas leakage prevention edges was created.

The above-mentioned thin plate and veneer were placed in a mold with a predetermined shape so as to obtain the desired structure as shown in Fig. 1, and heated at 150°C for 50 minutes.
Press molding was carried out at k (+/ci). Then, at about 150°C,
It was post-cured at 0.4 ko/ci and further carbonized and fired at 1200°C.

The physical properties of the obtained separator are shown below.

Gas permeability (at N2.0.2 ko/ctl
G)-? i, ax 10 ci/secocmH.

Electrical resistance 7.6 IllΩ, CI Thermal conductivity 4.7 kcal/m, hr, 'c Bending strength 860 ko/cd Gas isolation separator thickness 0.9 all Gas leak edge height 2.0 m.

Gas permeability to the side (at N2.0.2 ko/
cat G)-da 5.4X 10 d/seC, CrAHQEfi short carbon fiber navy blue (@Hane Kagaku, average fiber length 0,41111R
M-2048) 100 parts by weight and polyvinyl alcohol particles (manufactured by Nippon Gosei Chemical Co., Ltd.) as a pore control material 6
0 parts by weight and phenolic resin (Asahi Yukizai Co., Ltd., K.

RM-218), a mixture consisting of 60 parts by weight,
Supplied into a press molding mold of a predetermined shape, heated at 120°C and 40°C.
Press molding was performed at kQ/cd for 20 minutes to obtain a molded plate having a plurality of grooves.

Next, a mixture consisting of 100 parts by weight of the short carbon 11i1ft, 100 parts by weight of the polyvinyl alcohol, and 40 mold openings of the phenolic resin was supplied to a mold, and press-molded under the same conditions as above to obtain a flat plate.

After that, a graphite sheet with a thickness of 0.31-
(graph oil manufactured by UCC), supplying the molded plate thereon (with the groove facing up), and further supplying the flat plate,
Press molded at 150℃, 40ka/cm2 for 40 minutes, 1
Post-cure was carried out at 50° C. for 211 minutes.

A phenolic adhesive was applied to the graph oil surface of the molded product, and the molded product was supplied to a mold with the coated surface facing up.

Furthermore, the separator manufactured in Example 1 above was supplied thereon, and the molded body was fitted between the opposing edges. Next, the above molded body was supplied so as to fit between the edges of the separator with the graph oil surface coated with a phenolic adhesive facing down, and press-molded at 150°C and 25K (1/m) for 40 minutes. Post-cure at 150℃ for 2 hours, then further cure at 1000℃
The electrode substrate of the present invention was obtained by firing at the above temperature.

The physical properties of the obtained electrode substrate are shown in the table.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the electrode substrate for fuel cells of the present invention,
FIG. 2 is a perspective view of a separator used in the fuel cell electrode substrate of the present invention. DESCRIPTION OF SYMBOLS 1... Electrode substrate, 2... Electrode surface side layer, 3... Separator side layer, 4... Hollow hole path, 10... Separator, 11... Gas isolation separator part, 12...
Gas leak-proof edges. Procedural Amendment June 10, 1985 1, Case Description 1988 Patent Application No. 140259
No. 2, Title of the invention Fuel cell electrode substrate and its manufacturing method 3, Relationship with the case of the person making the amendment Name of patent applicant (118) Kureha Chemical Industry Co., Ltd. 6, Number of inventions increased by amendment 7, Amendment Target Specification 2, Claims (1) A porous carbonaceous layer as a gas diffusion layer, a separator, and the porous carbonaceous layer in this order, and the whole is fired and converted into carbon. In an electrode substrate for a fuel cell battery having a three-layer structure, the separator includes a gas isolation separator part that separates the reaction gas of the counter electrode into phase n, and a gas isolation separator part that separates the reaction gas of the counter electrode into phase n, and a gas isolation separator part that prevents the reaction gas from leaking to the side of the battery. a pair of the gas leak prevention edges are opposed to each other with the gas isolation separator section in between, and each pair of the gas leak prevention edges on both sides of the gas isolation separator section are The porous carbonaceous layers are joined to both sides of the gas isolation separator part, and the porous carbonaceous layers are bonded to both sides of the gas isolation separator part, and the porous carbonaceous layers are respectively orthogonal to each other and are integrated by carbonization firing. It has a hollow hole group as a reaction gas flow path approximately in the center of its thickness, and a lever plate is formed from the hollow hole group of the multi-porous and monoporous carbonaceous layer. An electrode substrate for a fuel cell, characterized in that the average bulk density on the side of the electrode surface is larger than the average bulk density on the side of the electrode surface. Ca/sec, cml-1g or less (7
) 7J S'fi'A Eft, bending strength of 500J/cm or more, 4kcal/II1. The electrode substrate according to claim 1, having a thermal conductivity of hr, °C or higher and an electrical resistance of 10n+ΩCl11 or lower. (3) The porous carbonaceous layer has an average bulk density of 0.4 to 0.8(]/ci and 20
All! /cm,hr,i+mA 10~100μ
The electrode substrate according to claim 2, characterized in that the electrode substrate has a diameter within the range [11]. 2. The electrode substrate according to any one of claims 1 to 3, wherein the layer on one side has an average bulk density of 0.5 to 1.0(]/Cffl. (5) Claims 1 to 1, characterized in that a graphite sheet is sandwiched between the lever-side layer of the porous carbonaceous layer and the separator, and the graphite sheet is carbonized and baked to be integrated. 4. A method for producing an electrode substrate for a fuel cell according to any one of Item 4, comprising: 100 parts by weight of short coal sl fiber;
A mixture of 20 to 100 parts by weight of a binder resin and 0 to 100 parts by weight of a granular polymer material having a predetermined particle size distribution is heated and press-molded to produce a molded plate having a plurality of hollow hole grooves; Similarly, 100 parts by weight of short-legged fibers.
A flat plate is prepared by heating and press-molding a mixture consisting of 20 to 1001 parts of a binder resin and 40 to 200 parts of a monolithic polymer substance, and the molded plate and the The flat plates were stacked in a mold with the grooves sandwiched between them, and the two molded bodies for porous carbonaceous layers obtained in this way were placed in a reaction gas as a counter electrode. , the pair of gas leak prevention edges are opposed to each other with the gas isolation separator section in between, and each pair of the gas leak prevention edges on both surfaces of the gas isolation separator section are orthogonal to each other;
It consists of joining using an adhesive so as to fit between the pair of gas leakage prevention edges of the lever regulator, which has been carbonized and fired, and then the whole is fired and carbonized to be integrated. Method. (7) When producing the molded article for the porous carbonaceous layer,
Graph 7 sheet is placed on the mold. Seiichi with the groove facing up
4. A method of heating and press forming by supplying a Japanese cedar board and the flat board in this order. (8) The lever is a fired and crushed oxide pitch product. 50 to 90 ffil carbon filler selected from non-graphitizable carbonaceous particles such as crushed carbon fiber products and fired phenol particles
A mixture consisting of i% and binder 10 to 50% by weight is supplied to a mold of a predetermined shape and manufactured at 70 to 130° C. for 30 minutes, and the thin plates and veneers are molded into a predetermined shape so as to have a predetermined structure at t'. 120~200℃, 30℃
8. The method according to claim 6 or 7, which is produced by press molding at ~200 kg/cIli and firing at a temperature of 1000° C. or higher. (9) The above [palator is a fired and crushed product of oxidized pitch]. A mixture consisting of a carbon fiber crushed product, a phenol particle fired product, etc. with a hard black content and a binder of 10 to 50% by weight is supplied to a mold of a predetermined shape, and heated at 120 to 200 °C and 30 to 200 °C.
The method according to claim 6 or 7, characterized in that it is produced by press-molding at 1/C#i and firing at a temperature of 1000°C or higher. .

Claims (9)

[Claims] (1) A fuel cell electrode substrate having a three-layer structure including a porous carbonaceous layer as a gas diffusion layer, a separator, and the porous carbonaceous layer in this order, and the entire structure is fired and integrated as carbon. The separator is comprised of a gas isolation separator section that isolates the reactive gases of the counter electrodes from each other, and a gas leakage prevention edge that prevents the reaction gas from leaking to the side of the cell, and a pair of the gas leakage prevention edges. The edges are opposed to each other across the gas isolation separator part, each pair of the gas leakage prevention edges on both sides of the gas isolation separator part are orthogonal to each other, and the whole is carbonized and baked to be integrated. The porous carbonaceous layer is bonded to both sides of the gas isolation separator portion, and is fitted between the pair of gas leakage prevention edges, respectively, and has a reactant gas flow channel approximately at the center of its thickness. 1. A fuel cell having a group of hollow holes as channels, and wherein the average bulk density of the porous carbonaceous layer on the side of the separator from the group of hollow holes is greater than the average bulk density of the porous carbonaceous layer on the side of the electrode surface from the group of hollow holes. Electrode substrate for (2) The gas isolation separator part has a thickness of 1.5 mm or less, and a thickness of 10^-^7 cm^2/sec. Gas permeability below cmHg, bending strength above 500kg/cm^2,
4kcal/m. hr. Thermal conductivity above ℃ and 10mΩ
The electrode substrate according to claim 1, having an electrical resistance of less than cm. (3) The porous carbonaceous layer has an average bulk density of 0.4 to 0.8 g/cm^3 and 20
ml/cm. hr. mmAq. The pores of the electrode surface side layer are open pores, and 60% or more of the pores have a diameter within the range of 10 to 100μ. An electrode substrate according to claim 1 or 2. (4) Claims 1 to 3, characterized in that a layer of the porous carbonaceous layer closer to the separator than the group of hollow holes has an average bulk density of 0.5 to 1.0 g/cm^3. The electrode substrate according to any one of Item 3. (5) Claims 1 to 4, characterized in that a graphite sheet is sandwiched between the separator side layer of the porous carbonaceous layer and the separator, and are integrated by carbonization firing. 3. The electrode substrate according to any one of the above. (6) A method for producing an electrode substrate for a fuel cell according to any one of claims 1 to 5, comprising: 100 parts by weight of short carbon fibers, 20 to 100 parts by weight of binder resin, and predetermined particles. A molded plate having a plurality of hollow hole grooves is manufactured by heating and press-molding a mixture consisting of 0 to 100 parts by weight of a granular polymer material having a diameter distribution, and similarly, 100 parts by weight of short carbon fibers and a binder. A flat plate is prepared by heat-pressing molding a mixture consisting of 20 to 100 parts by weight of a resin and 40 to 200 parts by weight of a granular polymer material having a predetermined particle size distribution, and the molded plate and the flat plate are sandwiched between the grooves. The thus obtained 2
A molded body for a porous carbonaceous layer is made up of a gas isolation separator part that isolates the reaction gas of the opposite electrode from each other, and a gas leakage prevention edge part that prevents the reaction gas from leaking to the side of the battery. The gas leakage prevention edges are opposed to each other across the gas isolation separator part, each pair of the gas leakage prevention edges on both sides of the gas isolation separator part are orthogonal to each other, and the gas leakage prevention edges are carbonized and fired. so as to fit between the pair of gas leakage prevention edges of the integrated separator;
A method that consists of joining using an adhesive and then sintering and carbonizing the whole to integrate it. (7) When producing the molded body for the porous carbonaceous layer, the graphite sheet, the molded plate with the grooves facing upward, and the flat plate are fed into a mold in this order and molded under heat and pressure. The method according to claim 6. (8) The separator is composed of 50 to 90% by weight of a carbon filler selected from non-graphitizable carbonaceous particles such as fired and crushed oxide pitch products, crushed carbon fiber products, and fired products of phenol particles, and 10 to 50% by weight of a binder. The mixture is supplied to a mold with a predetermined shape, and heated at 70 to 130°C and 30 to 200 kg/c.
A thin plate for the gas isolation separator part is manufactured by preforming m^2, and a veneer for the gas leakage prevention edge is similarly manufactured, and these thin plates and veneers are molded into a predetermined shape to have a predetermined structure. 120-200℃, 30-200kg
8. The method according to claim 6 or 7, which is produced by press forming at a temperature of /cm^2 and firing at a temperature of 1000° C. or higher. (9) The separator is made of 50 to 90% by weight of a carbon filler selected from non-graphitizable carbonaceous particles such as a fired and crushed oxide pitch product, a crushed carbon fiber product, and a fired product of phenol particles, and 10 to 50% by weight of a binder. The mixture consisting of
8. The method according to claim 6 or 7, which is produced by press forming at a temperature of /cm^2 and firing at a temperature of 1000° C. or higher.