JPH11185771A - Manufacture of paper and porous carbon plate for fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper sheet which can reduce contact resistance with a separator, and has homogeneous and excellent gas permeability, electrical conductivity and mechanical strength, in manufacturing a gaseous diffusion electrode plate such as a phosphoric acid holder and an electrode catalyst carrier in a phosphoric acid fuel cell, and an electrode catalyst carrier in a solid macromolecular fuel cell. SOLUTION: A paper sheet consisting of pitch carbon fiber 10-95 wt.% having a fiber diameter 1 μm and paper weight 50 g/m<2> , and polyester fiber 90-5wt.% having a carbonization yield less than 30% is heated at 160 deg.C and pressured. And a formed sheet formed by homogeneously attaching a melted phenolic plastic 55 wt.% having a carbonization yield 40-75 wt.% to the paper sheet is obtained. The formed sheet is vertically pinched by graphite plates, baked, and graphitized, thus a porous carbon plate for a fuel cell is manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a paper making material such as a phosphoric acid support or an electrode catalyst carrier in a phosphoric acid type fuel cell or a gas diffusion electrode plate such as an electrode catalyst carrier in a polymer electrolyte fuel cell. The present invention relates to a body and a method for producing a porous carbon plate for a fuel cell, which is useful for producing a gas diffusion electrode plate.

[0002]

2. Description of the Related Art For example, in the case of a phosphoric acid type fuel cell, phosphoric acid is used as an electrolyte and a thickness of 0.1 to
A 0.3 mm porous porous carbon plate is provided, and a platinum alloy catalyst as an electrode catalyst is supported on the surface thereof. A porous carbon plate as a phosphoric acid support having a thickness of 1 to 3 mm with a groove serving as a gas flow path and a separator are provided on the outside thereof to constitute a unit cell.

A porous carbon plate supporting an electrode catalyst has a controlled pore distribution and a high gas permeability.
Electrical conductivity, thermal conductivity, mechanical strength, phosphoric acid resistance and the like are required.

Further, it is required that the contact resistance between the porous carbon plate as the electrode catalyst carrier and the porous carbon plate as the phosphoric acid support be low. Further, it is required that the contact resistance between the porous carbon plate as the electrode catalyst support and the separator as the dense carbon plate is also low.

Conventionally, when a porous carbon plate as an electrode catalyst carrier as described above is manufactured, a carbon fiber paper body made of carbon fibers having a fiber diameter of 7 μm (meaning the fiber diameter, the same applies hereinafter) ( A method in which a binder such as a phenol resin is impregnated into paper weight (about 50 g / m ² ), heat-formed into a sheet by a hot press, and carbonized or graphitized.

In the case of manufacturing a porous carbon plate as a phosphoric acid support, a carbon fiber paper (made of paper having a basis weight of about 250 g / m ² ) made of carbon fibers having a fiber diameter of 7 to 20 μm is bonded to a binder such as a phenol resin. Is preliminarily compounded or impregnated later, and heated and pressed into a sheet by a hot press, followed by carbonization or graphitization.

In the case of a polymer fuel cell, a porous porous carbon plate having a thickness of 0.1 to 0.3 mm is provided on both sides of a polymer electrolyte membrane, and a platinum alloy catalyst as an electrode catalyst is supported on the surface thereof. I have. A separator, which is a dense carbon plate having a thickness of 1 to 3 mm and provided with a groove serving as a gas flow path, is provided on the outside thereof to constitute a unit cell.

The porous carbon plate supporting the electrode catalyst has a controlled pore distribution and high gas permeability.
Electrical conductivity, thermal conductivity, mechanical strength, phosphoric acid resistance and the like are required.

Further, it is required that the contact resistance between the porous carbon plate carrying the electrode catalyst and the separator, which is a dense carbon plate, be low.

Conventionally, when producing a porous carbon plate as an electrode catalyst carrier as described above, a carbon fiber paper body made of carbon fiber having a fiber diameter of 7 μm (paper basis weight of about 50 g / m ² )
Is impregnated with a binder such as a phenolic resin, heat-formed into a sheet by hot pressing, and carbonized or graphitized.

[0011]

However, in the case of a phosphoric acid type fuel cell, when producing a porous carbon plate as a platinum catalyst support and a porous carbon plate as a phosphoric acid support, respectively, In the method using the fiber paper body, since the fiber diameter of the carbon fiber is as large as 7 μm or more, the space between the porous carbon plate as the electrode catalyst support and the porous carbon plate as the phosphoric acid support, and the phosphoric acid support There is a drawback that the contact resistance between the porous carbon plate as a body and the separator is large, and the heat loss is large.

Further, the porous carbon plate which is a phosphoric acid support has a porosity of 50% because the carbon fiber has a large fiber diameter.
% Or more, and it was difficult to control the average pore diameter to 28 μm or less.

Also, in the case of the above-mentioned polymer type fuel cell, in the method using a papermaking body, since the fiber diameter of the carbon fiber is large, the distance between the porous carbon plate, which is the electrode catalyst carrier, and the separator is high. There were drawbacks of high contact resistance and large heat loss.

The present invention has been made in view of such circumstances, and the invention according to claims 1 and 2 relates to a phosphoric acid support or an electrode catalyst support in a phosphoric acid type fuel cell. When manufactured as a gas diffusion electrode plate such as an electrode catalyst carrier in a polymer electrolyte fuel cell, a homogeneous material that can reduce contact resistance with separators and has excellent gas permeability, electrical conductivity, and mechanical strength It is an object of the present invention to provide a papermaking body that can be made into a paper. And Claim 3
The invention according to the invention can reduce the contact resistance with a separator or the like in producing a gas diffusion electrode plate such as an electrode catalyst carrier in a phosphoric acid type fuel cell or a polymer electrolyte fuel cell, An object of the present invention is to provide a method for producing a homogeneous porous carbon plate having excellent conductivity and mechanical strength.

[0015]

According to a first aspect of the present invention, there is provided a paper body comprising a fiber having a fiber diameter of 1 to 4 μm or a fiber diameter of 0.5 μm, which can be formed into carbon fibers.
10 to 95% by weight of carbon fiber of ~ 3μm and 30% by weight of carbonization yield
It is characterized by comprising the following organic fibers of 90 to 5% by weight.

Examples of the fibers that can be converted into carbon fibers include various fibers that can be used as a carbon fiber material, for example, polyacrylonitrile fibers, phenol resin fibers, regenerated cellulose fibers (for example, rayon, polynosic fibers, etc.), and cellulosic fibers. Fiber and pitch-based fiber. The fibers that can be converted into carbon fibers may have been subjected to a flame-resistant treatment or an infusible treatment. Further, the fibers that can be converted into carbon fibers may be used alone or in combination of two or more.

The fiber diameter of the fiber which can be converted into carbon fiber is adjusted so that the fiber diameter when converted into carbon fiber is 0.5 to 3 μm.
〜4 μm is selected. If the thickness is less than 1 μm, the gas permeability tends to decrease, while if it exceeds 4 μm, the contact resistance increases.

Examples of the carbon fiber include fibers obtained by carbonizing or graphitizing the above-mentioned carbon fiber-forming fiber.
The carbon fibers may be used alone or in combination of two or more.

The carbon fiber has a fiber diameter of 0.5 to 3 μm. If it is less than 0.5 μm, the gas permeability tends to decrease, while if it exceeds 3 μm, the contact resistance increases.

The carbon fiber-forming fiber and the carbon fiber may be used alone, but preferably contain at least carbon fiber. In addition, when a fiber that can be converted into carbon fiber and a carbon fiber are used in combination, gas permeability and strength are improved. What is necessary is just to select suitably the ratio of the fiber which can be made into carbon fiber and carbon fiber according to the intensity | strength and electric conductivity of the porous carbon board manufactured.

Examples of the organic fibers include polyester fibers, polyacrylonitrile fibers, phenol resin fibers, regenerated cellulose fibers (for example, rayon, polynosic fibers, etc.) and cellulosic fibers. Organic fibers may be used alone or in combination of two or more.

As the organic fibers, those having a carbonization yield of 30% by weight or less are used. When the carbonization yield exceeds 30% by weight,
This is because it is difficult to form fine and uniform pores and to adjust the porosity.

The ratio of the above-mentioned carbon fiber or the organic fiber and the organic fiber is 10 to 95% by weight / 5 to 90% by weight. When the proportion of the carbon fiber-forming fiber or carbon fiber is less than 10% by weight, the contact resistance increases,
If it exceeds 95% by weight, the gas permeability tends to decrease.

Further, in order to achieve the above-mentioned object, the paper body of the invention according to claim 2 is a fiber having a fiber diameter of 1 to 4 μm or a carbon fiber having a fiber diameter of 0.5 to 3 μm. It is characterized by containing 20 to 50% by weight and 15 to 50% by weight of a binder having a carbonization yield of 40 to 75% by weight.

As the binder, for example, a thermosetting resin such as a phenol resin, a furan resin, a copna resin, a thermoplastic resin such as polyacrylonitrile, or coal or petroleum pitch can be used.

As the binder, in order to prevent a decrease in strength of the porous carbon plate to be produced and to adjust the porosity,
A carbonization yield of 40 to 75% by weight is used. Preferably
It is about 50 to 75% by weight.

The content of the above-mentioned carbon fiber or the carbon fiber which can be converted into carbon fiber is 20 to 50% by weight, and the content of the binder is 15 to 50% by weight. That is, the ratio of the fiber which can be converted into carbon fiber or the binder to carbon fiber is 30 to 250 parts by weight. If the amount is less than 30 parts by weight, the strength of the porous carbon plate to be produced tends to decrease,
If the amount exceeds 250 parts by weight, the gas permeability tends to decrease and the contact resistance increases.

Each of the above-mentioned papermaking bodies according to the first and second aspects of the present invention can be obtained by, for example, a suction molding method. As a suction molding method, a slurry containing each component is sucked by a suction molding die having a large number of suction holes, and the above-described components are deposited on the surface of the suction molding die, or the slurry is placed in the suction molding die. A method of injecting and sucking can be adopted. The density of the suction molded body obtained by the suction molding method can be easily controlled by the suction pressure.

In preparing the slurry, fibers that can be converted into carbon fibers or carbon fibers are beaten, and for example, 0.05 to 10 m
m, preferably 0.5 to 3 mm short fibers.
The solid content concentration of the slurry can be selected within a range that does not impair the suction moldability, and is, for example, about 0.1 to 2% by weight. The slurry may be added with a dispersant, a stabilizer, a viscosity modifier, an anti-settling agent, etc. in order to uniformly disperse the fibers and the binder, etc. A surfactant having an action, in particular, various additives such as a polymer flocculant and a retention aid may be added.

The paper body released from the suction mold is usually
It is dried by heating. The heating and drying of the wet paper body can be performed at a temperature of about 50 to 200 ° C. under normal pressure or reduced pressure.

According to a third aspect of the present invention, a method for manufacturing a porous carbon plate for a fuel cell according to the third aspect of the present invention includes the steps of: After compression-molding a carbonaceous preform to which 15 to 50% by weight of a binder is uniformly attached, the compression-molded article is carbonized or graphitized.

The paper is pressed while being heated at a temperature of 100 ° C. or higher, and the binder is melted to obtain a carbonaceous preform in which the binder is uniformly attached to the paper.

In the compression molding of the carbonaceous preform, for example,
It is performed by a method such as a die press or a roller press. This compression molding is preferably performed under heating in order to increase the uniformity of the molded body. The heating temperature can be appropriately selected,
Usually, it is about 100-250 ° C. The molding pressure is 30 ~
It is about 750 kgf / cm ² , preferably about 50 to 750 kgf / cm ² .

After compression-molding the carbonaceous preform, the compression-molded product is sandwiched between graphite plates from above and below, and calcined at a temperature of 800 ° C. or more in a vacuum or an inert gas atmosphere.
Graphitize at 1000-3000 ° C.

[0035]

According to the construction of the papermaking body according to the first and second aspects of the invention, the carbonized fiber diameter is set to 0.5 to 3 μm, and the porous carbon plate for a fuel cell manufactured by using this papermaking body is:
Compared to a conventional paper-made body having a fiber diameter of 7 μm, the number of fibers can be increased by 5.4 to 196 times at the same carbon fiber content. As a result, the number of contacts between carbon fibers in the porous carbon plate for a fuel cell can be increased by 5.4 to 196 times or more, and the internal electric resistance is reduced. Also, for example, to increase the contact area and contact opportunity with other members such as a separator,
Reduce contact resistance.

Further, according to a third aspect of the present invention, there is provided a method for producing a porous carbon plate for a fuel cell, comprising using the paper body of the first aspect of the present invention and uniformly adhering a binder. Disperse carbon fibers uniformly in the plate.

[0037]

Next, embodiments of the present invention will be described. Example 1 A pitch-based carbon fiber having a fiber diameter of 1 μm and a paper basis weight of 50 g / m ² (manufactured by Osaka Gas Co., Ltd.) 40% by weight (88.9% by weight as a paper body) and a carbonization yield of 5% by weight Polyester fiber (Nippon Textile Co., Ltd., 0.5 denier × 3mm) 5
Wt% (as the paper body, 11.1 wt%) and paper body (bulk density 0.05 g / cm ³⁾ while heating pressurized at 160 ° C., carbonization yield is 65% by weight of phenolic resin as binder comprising (Bellpearl S890: manufactured by Kanebo Co., Ltd.) 55% by weight is melted, and a phenolic resin is uniformly adhered to a papermaking body. A molded sheet (bulk density 0.7 g /
cm ³⁾ was obtained.

The above molded sheet is sandwiched between graphite plates from above and below,
It was calcined at 900 ° C. under vacuum or in an inert gas atmosphere, and then graphitized at 2000 ° C. to produce a porous carbon plate for a fuel cell. Properties of the obtained porous carbon plate for fuel cell (thickness mm, bulk density g / cm ³ , average pore diameter μm, gas permeability ml · Mm / cm ² · hr · mmAq, thermal conductivity in the thickness direction kcal /
m · Hr · ° C., flexural strength kg / cm ² , contact resistance between the porous carbon plate and the separator Ωcm; the same applies hereinafter), the results shown in Table 1 (No. 1 in the table) were obtained. .

[0039]

[Table 1]

Example 2 The fiber diameter in Example 1 was 1 μm and the paper basis weight was 50 g.
/ M ² pitch-based carbon fiber (manufactured by Osaka Gas Co., Ltd.) was replaced by pitch-based carbon fiber (manufactured by Osaka Gas Co., Ltd.) having a fiber diameter of 3 μm and a basis weight of 50 g / m ^2. A porous carbon plate for a fuel cell was manufactured in the same manner as in Example 1. When the characteristics of the obtained porous carbon plate for a fuel cell were measured, the results shown in Table 1 (No. 2 in the table) were obtained.

Example 3 A pitch-based carbon fiber having a fiber diameter of 1 μm and a paper basis weight of 50 g / m ² (manufactured by Osaka Gas Co., Ltd.) was 10% by weight (16.7% by weight as a paper body), and the carbonization yield was 5%. 50% by weight of polyester fiber (Nippon Textile Co., Ltd., 0.5 denier x 3 mm) 50
(The paper body, 83.3 wt%) wt% and paper body (bulk density 0.05 g / cm ³⁾ while heating pressurized at 160 ° C., carbonization yield is 65% by weight of phenolic resin as binder comprising (Bellpearl S890: manufactured by Kanebo Co., Ltd.) was melted at 40% by weight to obtain a molded sheet (bulk density: 0.7 g / cm ³ ).
The calcination and graphitization were performed in the same manner as in Example 1 to produce a porous carbon plate for a fuel cell. When the characteristics of the obtained porous carbon plate for a fuel cell were measured, Table 1 (No.
The result shown in 3) was obtained.

Example 4 The fiber diameter in Example 3 was 1 μm and the paper basis weight was 50 g.
/ M ² pitch-based carbon fiber (manufactured by Osaka Gas Co., Ltd.) was replaced by pitch-based carbon fiber (manufactured by Osaka Gas Co., Ltd.) having a fiber diameter of 3 μm and a basis weight of 50 g / m ^2. A porous carbon plate for a fuel cell was manufactured in the same manner as in Example 3. When the characteristics of the obtained porous carbon plate for a fuel cell were measured, the results shown in Table 1 (No. 4 in the table) were obtained.

Example 5 A pitch-based carbon fiber having a fiber diameter of 1 μm and a paper basis weight of 50 g / m ² (manufactured by Osaka Gas Co., Ltd.) was 50% by weight (94.3% by weight as a paper body), and the carbonization yield was 5%. Weight% polyester fiber (Nippon Textile Co., Ltd., 0.5 denier × 3mm) 3
Wt% (as the paper body, 5.7 wt%) and paper body (bulk density 0.05 g / cm ³⁾ while heating pressurized at 160 ° C., carbonization yield is 65% by weight of phenolic resin as binder comprising 47% by weight (Bellpearl S890: manufactured by Kanebo Co., Ltd.) was melted to obtain a molded sheet (bulk density: 0.7 g / cm ³ ).
The calcination and graphitization were performed in the same manner as in Example 1 to produce a porous carbon plate for a fuel cell. When the characteristics of the obtained porous carbon plate for a fuel cell were measured, Table 1 (No.
The result shown in 5) was obtained.

Example 6 The fiber diameter in Example 5 was 1 μm and the paper basis weight was 50 g.
/ M ² pitch-based carbon fiber (manufactured by Osaka Gas Co., Ltd.) was replaced by pitch-based carbon fiber (manufactured by Osaka Gas Co., Ltd.) having a fiber diameter of 3 μm and a basis weight of 50 g / m ^2. A porous carbon plate for a fuel cell was produced in the same manner as in Example 5. When the properties of the obtained porous carbon plate for a fuel cell were measured, the results shown in Table 2 (No. 6 in the table) were obtained.

[0045]

[Table 2]

Example 7 A pitch-based carbon fiber having a fiber diameter of 1 μm and a paper basis weight of 50 g / m ² (manufactured by Osaka Gas Co., Ltd.) was 40% by weight (66.7% by weight as a papermaking body), and the carbonization yield was 5%. 20% by weight polyester fiber (Nippon Textile Co., Ltd., 0.5 denier × 3mm)
Wt% (as the paper body, 33.3 wt%) and paper body (bulk density 0.05 g / cm ³⁾ while heating pressurized at 160 ° C., carbonization yield is 65% by weight of phenolic resin as binder comprising (Bellpearl S890: manufactured by Kanebo Co., Ltd.) was melted at 40% by weight to obtain a molded sheet (bulk density: 0.7 g / cm ³ ).
The calcination and graphitization were performed in the same manner as in Example 1 to produce a porous carbon plate for a fuel cell. When the characteristics of the obtained porous carbon plate for a fuel cell were measured, Table 2 (No.
The result shown in 7) was obtained.

Example 8 The fiber diameter in Example 7 was 1 μm and the paper basis weight was 50 g.
/ M ² pitch-based carbon fiber (manufactured by Osaka Gas Co., Ltd.) was replaced by pitch-based carbon fiber (manufactured by Osaka Gas Co., Ltd.) having a fiber diameter of 3 μm and a basis weight of 50 g / m ^2. A porous carbon plate for a fuel cell was manufactured in the same manner as in Example 7. When the characteristics of the obtained porous carbon plate for a fuel cell were measured, the results shown in Table 2 (No. 8 in the table) were obtained.

Example 9 (Example of papermaking body of the invention according to claim 2) Bonded to 50% by weight of pitch-based carbon fiber (manufactured by Osaka Gas Co., Ltd.) having a fiber diameter of 1 μm and a paper weight of 50 g / m ^2. A papermaking body (bulk density 0.7 g / cm ³ ) preliminarily blended with 50% by weight of a phenol resin (Bellpearl S890: manufactured by Kanebo Co., Ltd.) having a carbonization yield of 65% by weight as an agent was prepared in the same manner as in Example 1. After firing and graphitization, a porous carbon plate for a fuel cell was manufactured. When the characteristics of the obtained porous carbon plate for a fuel cell were measured, the results shown in Table 2 (No. 9 in the table) were obtained.

Example 10 (Example of the papermaking body of the invention according to claim 2) The fiber diameter in Example 9 was 1 μm and the paper basis weight was 50 g.
/ M ² pitch-based carbon fiber (manufactured by Osaka Gas Co., Ltd.) was replaced by pitch-based carbon fiber (manufactured by Osaka Gas Co., Ltd.) having a fiber diameter of 3 μm and a basis weight of 50 g / m ^2. A porous carbon plate for a fuel cell was produced in the same manner as in Example 9. When the characteristics of the obtained porous carbon plate for a fuel cell were measured, the results shown in Table 2 (No. 10 in the table) were obtained.

Comparative Example 1 40% by weight of a PAN-based carbon fiber (manufactured by Toray Industries, Inc.) having a fiber diameter of 7 μm and a basis weight of 50 g / m ² , and a polyester fiber having a carbonization yield of 5% by weight (manufactured by Nippon Textile Co., Ltd.) , 0.5 denier × 3 mm) and 5% by weight (bulk density: 0.05 g)
/ Cm ³ ) while heating at 160 ° C., and applying a phenol resin (Bellpearl S) with a carbonization yield of 65% by weight as a binder.
890: manufactured by Kanebo Co., Ltd.) was melted to obtain a molded sheet (bulk density: 0.7 g / cm ³ ). The calcination and graphitization were performed in the same manner as in Example 1 to produce a porous carbon plate for a fuel cell. When the characteristics of the obtained porous carbon plate for a fuel cell were measured, the results shown in Table 3 (No. 1 in the table) were obtained.

[0051]

[Table 3]

Comparative Example 2 10% by weight of a PAN-based carbon fiber (manufactured by Toray Industries, Inc.) having a fiber diameter of 7 μm and a paper weight of 50 g / m ² , and a polyester fiber having a carbonization yield of 5% by weight (manufactured by Nippon Textile Co., Ltd.) , 0.5 denier x 3 mm) 50% by weight (bulk density 0.05 g)
/ Cm ³ ) while heating at 160 ° C., and applying a phenol resin (Bellpearl S) with a carbonization yield of 65% by weight as a binder.
890: Kanebo Co., Ltd.) was melted to obtain a molded sheet (bulk density: 0.7 g / cm ³ ). The calcination and graphitization were performed in the same manner as in Example 1 to produce a porous carbon plate for a fuel cell. When the characteristics of the obtained porous carbon plate for a fuel cell were measured, the results shown in Table 3 (No. 2 in the table) were obtained.

Comparative Example 3 50% by weight of a PAN-based carbon fiber (manufactured by Toray Industries, Inc.) having a fiber diameter of 7 μm and a paper weight of 50 g / m ² , and a polyester fiber having a carbonization yield of 5% by weight (manufactured by Nippon Textile Co., Ltd.) , 0.5 denier x 3 mm) 3% by weight
/ Cm ³ ) while heating at 160 ° C., and applying a phenol resin (Bellpearl S) with a carbonization yield of 65% by weight as a binder.
890: manufactured by Kanebo Co., Ltd. (47% by weight) was melted to obtain a molded sheet (bulk density: 0.7 g / cm ³ ). The calcination and graphitization were performed in the same manner as in Example 1 to produce a porous carbon plate for a fuel cell. When the characteristics of the obtained porous carbon plate for a fuel cell were measured, the results shown in Table 3 (No. 3 in the table) were obtained.

Comparative Example 4 PAN-based carbon fiber (manufactured by Toray Industries, Inc.) having a fiber diameter of 7 μm and a basis weight of 50 g / m ² , and a polyester fiber having a carbonization yield of 5% by weight (manufactured by Nippon Textile Co., Ltd.) , 0.5 denier x 3 mm) and 20% by weight (bulk density 0.05 g)
/ Cm ³ ) while heating at 160 ° C., and applying a phenol resin (Bellpearl S) with a carbonization yield of 65% by weight as a binder.
890: Kanebo Co., Ltd.) was melted to obtain a molded sheet (bulk density: 0.7 g / cm ³ ). The calcination and graphitization were performed in the same manner as in Example 1 to produce a porous carbon plate for a fuel cell. When the characteristics of the obtained porous carbon plate for fuel cells were measured, the results shown in Table 3 (No. 4 in the table) were obtained.

Comparative Example 5 A PAN-based carbon fiber (manufactured by Toray Industries, Inc.) having a fiber diameter of 7 μm and a basis weight of 50 g / m ² was added to 50% by weight of a phenol resin (Bellpearl) having a carbonization yield of 65% by weight as a binder. S8
90: manufactured by Kanebo Co., Ltd. A paper body (bulk density 0.7 g / cm ³ ) preliminarily blended with 50% by weight was calcined and graphitized in the same manner as in Example 1 to obtain a porous carbon plate for a fuel cell. Manufactured. When the characteristics of the obtained porous carbon plate for a fuel cell were measured, the results shown in Table 3 (No. 5 in the table) were obtained.

From the above results, the following was clear. Although the bulk density is the same, the average pore diameter of the porous carbon plate for the fuel cell of the example is 28 μm as compared with the comparative example.
It can be controlled as follows, and the gas permeability can be improved.
Without lowering the strength, the porous carbon plate for the fuel cell of the example can significantly improve the thermal conductivity as compared with the comparative example, and can greatly reduce the contact resistance between the porous carbon plate and the separator. ing.

[0057]

As is apparent from the above description, according to the papermaking bodies of the first and second aspects of the present invention, when manufactured as a gas diffusion electrode plate, the number of fibers with the same carbon fiber content is reduced. And the number of contacts between the carbon fibers in the inside can be increased, so that the internal electric resistance can be reduced and the electric conductivity can be improved. Further, since the average pore diameter can be controlled to be small, gas permeability can be improved. In addition, since the number of fibers at the same carbon fiber content increases, without decreasing the strength, and, for example,
A porous carbon plate and a separator for supporting an electrode catalyst in a polymer fuel cell, a porous carbon plate and a separator as a phosphoric acid support for a phosphoric acid fuel cell, and a phosphoric acid support for a phosphoric acid fuel cell The contact area and contact opportunity between the porous carbon plate and another member such as a porous carbon plate for supporting an electrode catalyst can be increased, the contact resistance between them can be reduced, and the heat loss can be reduced.

According to the method for manufacturing a porous carbon plate for a fuel cell according to the third aspect of the present invention, the binder is uniformly attached to the papermaking body according to the first aspect of the invention, and Since the carbon fibers are uniformly dispersed in the porous carbon plate, when manufactured as a gas diffusion electrode plate, a porous carbon plate with excellent quality in all of gas permeability, electrical conductivity, mechanical strength and contact resistance surface Can now be manufactured.

Claims (3)

[Claims] 1. A fiber having a fiber diameter of 1 to 4 μm or a carbon fiber having a fiber diameter of 0.5 to 3 μm and a carbon fiber yield of 30 to 5% by weight and a carbonization yield of 30 to 5% by weight. And a paper body comprising: 2. A fiber having a fiber diameter of 1 to 4 μm or a carbon fiber having a fiber diameter of 0.5 to 3 μm and a binder having a carbonization yield of 40 to 75% by weight and a binder of 15 to 50% by weight. %. 3. The papermaking body according to claim 1, wherein the carbonization yield is 40 to 40%.
After compression-molding a carbonaceous preform to which 15 to 50% by weight of a binder of 75% by weight is uniformly adhered, the compression-molded article is carbonized or graphitized. Plate manufacturing method.