JP3437936B2 - Fuel cell separator with ribs, method for producing the same, and fuel cell - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ribbed fuel cell separator for separating fuel gas and oxidant gas (air or oxygen) of a fuel cell, a method for producing the same, and a fuel cell.

[0002]

2. Description of the Related Art Fuel cells are expected to be widely used in the future for small power generators and EV power sources because of their high energy efficiency and low environmental pollution. In a fuel cell, electrodes (positive and negative electrodes) are arranged above and below the electrolyte layer, and a fuel gas and an oxidant gas (air or oxygen) are made to flow above and below the electrodes to carry out oxidation and reduction reactions at the electrodes, migration of cations and electrons in the electrolyte layer. The principle is that chemical energy is converted into electric energy in the reaction to obtain a potential difference. Since the fuel cell is manufactured with a structure in which the electrodes and the electrolyte layers are alternately stacked in multiple stages, a separator (separator) for separating the fuel gas and the oxidant gas is provided between the stacked positive and negative electrodes. Further, a structure in which ribs (grooves) are provided on the separator is generally used to secure a gas supply path. Further, the potential difference obtained by the unit cell is generally of a structure in which current is collected by an outer current collector plate laminated in multiple stages.

Therefore, the separator has 1) separation of fuel gas and oxidant gas (gas impermeability), 2) electrical conductivity,
3) It is required to have characteristics such as not being swollen by water generated in the negative electrode and the electrolytic solution. This separator is generally manufactured by a method in which a groove is machined in a graphite block or glassy carbon to form a rib to secure a supply path for fuel gas and an oxidant gas.

Further, a method of molding expanded graphite or an expanded graphite sheet obtained by treating scaly natural graphite with acid and then heating it, or in order to prevent swelling with respect to a liquid, a pre-expanded graphite molded product is liquid. It was produced by the method of impregnating and curing the thermosetting resin of JP-A-60-65781 and JP-A-60-12672.

International publication number WO97 / 02612
The specification describes a method in which expanded graphite powder having a specific particle diameter is dispersed in a thermoplastic resin or a thermosetting resin to obtain a block-shaped molded body, and then the groove is machined. However, the above-described various manufacturing methods for machining increase the cost, and in the manufacturing method using expanded graphite, the size of ribs that can be manufactured is limited, and swelling occurs in the product due to the gas generated during molding. There was a problem that the product could not be supplied easily and stably.

[0006]

The invention described in claims 1 to 8 is to solve the above-mentioned problems, and in a fuel cell separator with a rib, gas impermeability, electrical conductivity, and liquid expansion are provided. Wetness can be ensured, and the flat plate can be made thin to reduce the weight even in the shape of high ribs.
Thus, the present invention provides a ribbed separator that facilitates thermocompression molding of a battery .

[0007] Also, the invention described in claim 9, in addition to the above problems, a stable battery characteristics even when used for a long time separator is to provide a ribbed separator can be ensured.

According to a tenth aspect of the invention, in the method of manufacturing a fuel cell separator having a rib, gas impermeability, electrical conductivity, and liquid swelling are ensured, and the rib height is high. It is intended to provide a method for manufacturing a ribbed separator that can reduce the weight of the flat plate portion even in terms of shape and can reduce the weight. The invention described in claim 11 ensures gas impermeability, electrical conductivity, and liquid swellability,
Further, even when the rib height is high, the flat plate portion has a thin plate thickness and has a lightweight ribbed separator, thereby providing a high-performance fuel cell. further,
In addition to the above problems, the invention according to claim 12 provides a fuel cell capable of ensuring stable cell characteristics even when the separator is used for a long period of time.

[0009]

DISCLOSURE OF THE INVENTION The present invention comprises a granulated powder obtained by crushing a sheet of expanded graphite preformed in a resin and having an average particle size of 50 μm or more and 200 μm or less. Ri but name are integrally molded, ribs twice
On the ribbed fuel cell separator that having a taper of 20 degrees. Further, in the present invention, the average particle size in the resin is 50 μm.
A fuel in which expansive graphite of m or more and 200 μm or less is dispersed, a rib and a flat plate are integrally formed, and a ratio (A / B) of the height (A) of the rib and the plate thickness (B) of the flat plate is 2 or more. It relates to a battery separator. The present invention also relates to the above fuel cell separator having a rib height of 0.5 mm or more. The present invention also relates to the above fuel cell separator having a rib height of 1.0 mm or more. The present invention also relates to a fuel cell separator in which the rib is arranged on one side of a flat plate.

The present invention also relates to a fuel cell separator in which the ribs are arranged on both sides of a flat plate. The present invention also relates to a fuel cell separator in which the plate thickness of the flat plate is 0.25 mm to 1.0 mm. Further, in the present invention, the thickness of the flat plate portion is 0.25 mm to 1.0 mm, and the ratio (A / B) of the rib height (A) to the flat plate thickness (B) is 2
The above is related to the fuel cell separator . Also, the present invention is the fuel cell of a fuel cell separator is a solid polymer type.

The present invention also provides a mixture of a granulated powder obtained by pulverizing a sheet of expanded graphite preformed and having an average particle size of 50 μm or more and 200 μm or less and a thermosetting resin or a thermoplastic resin. The present invention relates to a method for manufacturing a fuel cell separator with ribs, which is characterized in that the above is used as a raw material and is integrally thermocompressed using a mold. The present invention also relates to a fuel cell including the above fuel cell separator. Furthermore, the present invention relates to a fuel cell in which the fuel cell is a polymer electrolyte type.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A ribbed fuel cell separator according to the present invention will be described with reference to the drawings. 1 is a cross-sectional view of a separator of both ribs in which the ribs 1 are arranged on both sides of a flat plate 2, FIG.
FIG. 3 is a cross-sectional view of a single rib separator in which the rib 1 is arranged on one surface of the flat plate 2. FIG. 3 is a partial cross-sectional view of a fuel cell in which the separator 3, the electrolyte layer 8 and the electrodes (4 and 6) are combined. The separator 3 includes a fuel gas 5 flowing in the positive electrode 4 and an oxidant gas (air flowing in the negative electrode 6). Or oxygen) 7 is separated.

The separator of the present invention is a granulated powder obtained by crushing a sheet of expanded graphite preformed in a resin and having an average particle size of 50 μm to 200 μm (hereinafter referred to as “expanded graphite powder”). In general, the raw material is obtained by using expanded graphite powder and a thermosetting resin or a thermoplastic resin as raw materials and integrally molding them, preferably by thermocompression molding. The expansive graphite used for producing the expansive graphite powder may be one produced by a known production method disclosed in JP-A-54-33799 or the like. For example, graphite with a highly developed crystal structure such as natural graphite, quiche graphite, and pyrolytic graphite is immersed in a strongly oxidizing solution such as a mixed solution of concentrated sulfuric acid and nitric acid or a mixed solution of concentrated sulfuric acid and hydrogen peroxide solution. Then, expanded graphite having a compressive property is used in which a graphite intercalation compound is generated, washed with water, and then rapidly heated to expand the C axis direction of the graphite crystal, and which has a compression characteristic.

In the separator of the present invention , the expanded
Granulated powder state expanded graphite was ground preformed sheet a constant pressure is used, the use of such a granulated powder
The gas generating less contained in the expanded graphite when mixed with resin powder molding, further remains entanglement of the expanded graphite, reinforcing effect of the resin is Ru can improve the strength of the separator easy to secure. The above granulated powder is referred to below as "expanded graphite
Granular powder ".

The expansion ratio of expanded graphite is the strength of the separator,
In order to secure the sealing property, the higher the better, 150
It is more preferable that the number is twice or more. The average particle size of the expanded graphite granulated powder mixed with the resin is in the range of 50 μm to 200 μm. If the average particle size is less than 50 μm, the effect of entanglement of the expanded graphite is reduced and the strength of the separator is reduced. In the present invention, the average particle size is a number average value and can be measured by a particle size distribution measuring device such as SALD-3000J manufactured by Shimadzu Corporation.

The resin used in the present invention is a thermosetting resin such as powdery or liquid epoxy resin, phenol resin, melamine resin, polyamide resin, polyamideimide resin, polycarbonate resin, phenoxy resin or the like having heat resistance. A plastic resin is used.

The resin to be used is preferably a thermosetting resin in view of heat resistance and corrosion resistance, and particularly in workability, a powdered phenol resin which generates less gas during hot press molding is preferable. As the phenol resin, a resin polymerized by ring-opening polymerization, for example, a phenol resin containing a dihydrobenzoxazine ring is preferable because gas generation is particularly small.

In the case of a powdery resin, its particle size distribution is not particularly limited, but in order to uniformly mix it with the expanded graphite granulated powder in a dry manner, the resin flow at the time of molding is taken into consideration, and 1 μm to 100 μm.
The average particle size is preferably 5 μm to 50 μm
More preferably, the average particle size is m.

The rib shape of the separator of the present invention is optimized in consideration of the flow passage cross-sectional area that affects the gas supply amount, the contact area between the rib and the electrode that affects the vertical conductivity, and the contact area between the electrode and the gas. Set by value. From the above examination, the height of the rib is preferably 0.5 mm or more and 1.0
More preferably, it is 1.0 mm to 3. mm.
More preferably, it is 0 mm. 0. If it is less than 5 mm, the dimensions of the electrode and the separator are small and the flow path resistance is large, so that it tends to be difficult to stabilize the gas supply amount. On the other hand, if the size exceeds 3.0 mm, the size of the battery becomes large, which is not preferable.

The ratio (A / B) of the rib height (A) to the plate thickness (B) of the flat plate is preferably 2 or more, and when it is 2 to 5, the battery size is reduced and the weight is reduced. More preferable above. If A / B is less than 2, the flat plate thickness becomes excessively thick in order to secure a stable flow rate, and the conductivity in the thickness direction tends to deteriorate. On the other hand, when it exceeds 5, the rib of the separator becomes too high with respect to the thickness of the flat plate, the rigidity of the separator is insufficient, and the separator may be damaged during the battery assembly. The definitions of the rib height (A) and the flat plate thickness (B) are shown in FIGS. 1 and 2.

The rib of the present invention may be both ribs having ribs arranged on both sides of the flat plate shown in FIG. 1 or may be one rib having ribs arranged on one side of the flat plate shown in FIG. Since both ribs need only one flat plate, the battery can be made smaller and lighter than a single rib.

The plate thickness of the flat plate is preferably 0.25 mm to 1.0 mm. If it is less than 0.25 mm, the gas seal level of the separator tends to deteriorate. On the other hand, if it exceeds 1.0 mm, the weight of the separator cannot be reduced and the electrical resistivity tends to increase.

Further, the ribs are required you to assign 2 20 degrees of taper (C). The definition of the angle of C is shown in FIG. The angle of the taper is less than 2 degrees, it is difficult to separate from the mold the product which is integrally molded, on the other hand,
When the rib angle exceeds 20 degrees, the contact area of the electrode and the cross-sectional area of the flow channel are reduced, which is not preferable in terms of size and weight reduction.

The separator of the present invention is filled with the mixture of the expanded graphite granulated powder and the resin using a mold capable of forming a desired separator shape, and is integrally molded, preferably thermocompression molded. There is no particular limitation on the mixing ratio of the expanded graphite granulated powder and the resin, but considering the moldability and characteristics, the expanded graphite granulated powder /
Resin = 95/5 to 20/80 (weight ratio) is preferable, and 10/90 to 30/70 is particularly preferable. Here, if the amount of the expanded graphite granulated powder to be mixed exceeds 95/5, the formability tends to decrease, and the mechanical strength tends to decrease sharply due to insufficient matrix. On the other hand, 2
If it is less than 0/80, the conductivity tends to decrease.

There is no limitation on the mixing method of the expanded graphite granulated powder and the thermosetting resin or the thermoplastic resin. When a liquid resin or a solid resin dissolved in a solvent is used, it can be obtained by mixing a predetermined amount of expanded graphite powder and a resin solution in a container and stirring the mixture uniformly with a stirrer. Here, the mixture produced by using the resin containing the solvent is usually used after being desolvated with a vacuum dryer or the like and pulverized. Also, a method of dry blending the expanded graphite granulated powder and a powdery resin (method of mixing without solvent with a shaker, mixer or the like) can be used. The dry blending method is preferable in consideration of cost and workability.

The molding conditions of the fuel cell separator can be selected according to the type of resin and are not particularly limited,
Usually, the molding temperature may be from room temperature to 400 ° C, and the preferable temperature is from 150 ° C to 200 ° C.
If the temperature is lower than 150 ° C, the molded product is insufficiently cured, and the uncured component may be eluted during actual use. Further, when the temperature exceeds 200 ° C., it is hardened rapidly, so that it is difficult to harden it uniformly, and the product may be deformed. Also preferred molding pressure is ^{20 kg / cm 2 ~100kg / cm} 2. Two
If it is less than 0 kg / cm ² , the molded product will have a low density, and the gas performance will tend to deteriorate, such as a decrease in gas permeability and an increase in electrical specific resistance. On the other hand, if it exceeds 100 kg / cm ² , the molded product has a high density, and product burrs are apt to occur during hot-pressing, which tends to deteriorate workability.

Further, depending on the type of resin, it is also possible to provide a step of removing a gas of an unnecessary substance such as condensed water generated during curing. Further, in order to further cure the obtained molded product, a heat treatment may be performed after the molding.

Possible uses of the separator of the present invention are alkaline aqueous solution type, acid aqueous solution type, solid polymer type fuel cells and the like . As an electrolyte of the fuel cell, in the case of an alkali aqueous solution-type or potassium hydroxide is used, such as phosphoric acid is used in the case of acid solution type, in the case of a solid polymer ion exchange membrane or the like is found using. Examples of the base material of the electrode include a carbon material such as carbon fiber, and if necessary, a material provided with a catalyst layer of platinum, palladium, silver, nickel or the like on the surface is used. Hydrogen, which is a fuel gas, is supplied by reacting raw materials such as water decomposition products and natural gas, petroleum, coal, methanol, etc. with water, etc. as necessary to extract hydrogen-rich reformed gas and using it. It The separator of the present invention is most preferably applied to a solid polymer type fuel cell in consideration of operating temperature, corrosion resistance to an electrolyte and the like.

[0029]

EXAMPLES Examples of the present invention will be described below. Example 1 Expanded graphite sheet having a plate thickness of 1.0 mm and a density of 1.0 g / cm ³ (manufactured by Hitachi Chemical Co., Ltd., trade name Carbofit H)
GP-105) was crushed with a coarse crusher and a fine crusher to obtain 700 g of expanded graphite granulated powder having an average particle size of 100 μm. Next, 300 g of resol-type phenol resin powder (trade name: TD2040C, manufactured by Dainippon Ink and Chemicals, Inc.) was added, and dry mixed with a small V-type blender to obtain 1000 g of mixed powder.

The rib height is 2.5 mm and the flat plate thickness is 0.5.
100 mm x 100 having a rib taper of 10 degrees with a uniform pitch of 2 mm in the concave portion of the rib and 2 mm in the convex portion.
In order to form a separator having a size of mm, a mold having a transferred shape of the separator was heated in advance to 180 degrees, and the above-described mixed powder was weighed at 2000 g / m ² and weighed 20 g, and then uniformly charged into the mold. Surface pressure 50kg / c with 180 degree hot press
The separator was compressed and molded under the conditions of m ² , molding time of 10 minutes, and degassing 3 times to obtain a separator having a prescribed rib shape and a density of 1.4 g / cm ³ .

Example 2 (1) Production of phenol resin (resin containing dihydrobenzoxazine ring) for ring-opening polymerization 1.9 kg of phenol, formalin (37% aqueous solution)
1.0 kg and 4 g of oxalic acid were charged in a 5 liter flask and reacted at reflux temperature for 6 hours. Subsequently, the interior was depressurized to 6666.1 Pa (50 mmHg) or less to remove unreacted phenol and water, and a phenol novolac resin was synthesized. The obtained resin had a softening point of 84 ° C. (ring and ball method) and a trinuclear to polynuclear / dinuclear ratio of 92/18 (peak area ratio by gel permeation chromatography).

Next, 1.7 kg (corresponding to 16 mol of hydroxyl groups) of the synthesized phenol novolac resin was mixed with 0.93 kg (corresponding to 10 mol) of aniline and stirred at 80 ° C. for 5 hours to prepare a uniform mixed solution. did. Then, 1.62 kg of formalin was charged into a 5 liter flask and heated to 90 ° C., and the above novolak / aniline mixed solution was added little by little over 30 minutes. After the addition is complete
After maintaining the reflux temperature for 30 minutes, and then reducing the pressure to 6666.1 Pa (50 mmHg) or less at 100 ° C. for 2 hours to remove condensed water, 71 mol% of a hydroxyl group capable of reacting
A resin containing a dihydrobenzoxazine-modified dihydrobenzoxazine ring was obtained.

(2) Production of separator Expanded graphite sheet having a plate thickness of 1.0 mm and a density of 1.0 g / cm ³ (trade name: Carbofit H, manufactured by Hitachi Chemical Co., Ltd.)
GP-105) was crushed with a coarse crusher and a fine crusher to obtain 700 g of granulated powder having an average particle size of 100 μm. Next, 300 g of the phenol resin powder produced by the above method was added and dry mixed with a small V-type blender to obtain 1000 g of mixed powder.

The rib height is 2.5 mm and the flat plate thickness is 0.5.
100 mm x 100 having a rib taper of 10 degrees with a uniform pitch of 2 mm in the concave portion of the rib and 2 mm in the convex portion.
In order to form a mm separator, a mold having a transferred separator shape was heated to 180 degrees in advance, and the above-mentioned mixed powder was weighed at 2000 g / m ² and weighed 20 g, and then uniformly charged into the mold. Surface pressure 50kg / cm ² with 180 degree hot press,
A separator having a prescribed rib shape and a density of 1.4 g / cm ³ was obtained by compression molding under the conditions of molding time of 10 minutes and degassing once.

Example 3 Using the mixed powder obtained in Example 2 (2), the rib height was 0.5 mm, the flat plate thickness was 0.25 mm, and the rib depressions were 0.
8 mm with a uniform pitch of 4 mm and protrusions of 0.4 mm
In order to form a 100 mm × 100 mm separator having a rib taper of 100 degrees, a mold having a transferred shape of the separator is heated to 180 degrees in advance, and the mixed powder described above has a basis weight of 200.
After weighing 0 g / m ² and weighing 4.43 g, the mixture was uniformly charged into the mold. A 180 ° hot press was used to perform compression molding under the conditions of a surface pressure of 50 kg / cm ² , molding time of 10 minutes and degassing once to obtain a separator having a prescribed rib shape and a density of 1.4 g / cm ³ .

Comparative Example 1 14 expanded graphite powder having a bulk density of 0.002 g / cm ³ (trade name: Carbofit HGP-1 manufactured by Hitachi Chemical Co., Ltd.) was used.
g, uniformly charged into the molding die used in Example 1, surface pressure of 50 kg / cm ² under normal temperature conditions, pressure molding under three degassing conditions, and density of 1.0 g / cm ^3. A separator of expanded graphite alone was obtained.

Comparative Example 2 Melamine-modified phenolic resin (trade name: PR-406, manufactured by Hitachi Chemical Co., Ltd.) was added to the separator obtained in Comparative Example 1.
0) for 12 hours to wash the resin on the surface of the molded body with toluene, then raise the temperature to 25 to 160 ° C. and heat cure to obtain a separator having a resin impregnation rate of 30% by weight and a density of 1.3 g / cm ³ . Obtained.

Next, the electrical resistivity, gas permeability and liquid swelling property of the separators obtained in each of the above Examples and Comparative Examples were confirmed. The electrical resistivity is 50 mm x 50 mm at the same density as the separator, apart from the actual separator.
A sample having a plate thickness of 12 mm was compression-molded and the electrical resistivity in the plate thickness direction was measured by the voltage drop method. The gas aeration rate is calculated by the following formula by sealing the periphery of the separator with silicone rubber, applying an air pressure of 1 kg / cm ² on one side, measuring the amount of air leakage Q by the submersion method.

[0039]

## EQU1 ## Air permeability = Q / T × D / S In the above formula, T is the pressing time (seconds), D is the plate thickness (mm) of the test piece, and S is the pressure receiving area (cm ² ). The liquid swelling property is obtained by immersing the separator in warm water at 90 ° C. for 24 hours and measuring the plate thickness change rate. Table 1 shows the appearance and results of the physical property confirmation of the separator.

[0040]

[Table 1]

As is clear from the above Examples and Comparative Examples, the ribbed fuel cell separator of the present invention has a rib height of 0.5 mm or more, preferably 1.0 mm, in a fuel cell that needs to be compact and lightweight. With the above, the plate thickness of the flat plate is 0.25
An ideal shape in which the ratio of the rib height (A) to the thickness (B) of the flat plate is from 2 to 5 is mixed with expanded graphite granulated powder and thermosetting and thermoplastic resins. It can be secured by integral thermocompression molding. Further, the obtained separator is excellent in electrical conductivity, gas permeability and liquid swelling property, and stable properties can be secured even when used as a separator for a long period of time.

[0042]

The ribbed separator described in claims 1 to 8 is excellent in gas impermeability, electrical conductivity, and liquid swelling property, and the plate thickness of the flat plate portion is high even when the rib height is high. Can be made thin, in this case it is possible to reduce the weight ,
It is easy to perform thermocompression molding of batteries .

In addition to the above effects, the ribbed separator according to the ninth aspect can secure stable battery characteristics even when the separator is used for a long period of time. According to the preparation of ribbed separators described in claim 10, impermeable gas, electrical conductivity, to ensure Eki膨 Junsei, plate thickness of the flat portion even in yet higher height of the rib-shaped It is possible to manufacture a separator that can be formed thin and can be made lightweight. The fuel cell according to claim 11 is excellent in gas impermeability, electrical conductivity, and liquid swelling property, and further, even in a shape in which the rib height is high, the flat plate portion is thin, Since it has a ribbed separator that is light in weight, it has high performance. In addition to the above effects, the fuel cell according to the twelfth aspect can ensure stable cell characteristics even when the separator is used for a long period of time.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of both rib separators of the present invention.

FIG. 2 is a cross-sectional view showing an example of the single-rib separator of the present invention.

FIG. 3 is a partial cross-sectional view of a fuel cell using both rib separators.

[Explanation of symbols]

1 rib 2 flat plates 3 Double rib separator 4 positive electrode 5 Fuel gas passage 6 Negative electrode 7 Oxidant gas passage 8 Electrolyte layer

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Harufumi Hasuda 3-3-1, Ayukawa-cho, Hitachi-shi, Ibaraki Yamashita factory, Hitachi Ritsuka Kogyo Co., Ltd. (56) Reference JP-A-6-84526 (JP, 6-84526) A) JP 10-40937 (JP, A) JP 8-96798 (JP, A) JP 2000-223133 (JP, A) JP 11-354136 (JP, A) JP 11- 354135 (JP, A) International Publication 97/002612 (WO, A1) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01M 8 / 02,8 / 10

Claims (12)

(57) [Claims] 1. A granulated powder obtained by crushing a sheet obtained by pre-expanding expanded graphite in a resin, having an average particle size of 50 μm or more 20.
0 [mu] m will be distributed following ones, the ribs and the flat plate Ri is Na are integrally molded, ribbed fuel cell separator that ribs have a taper of 2 degrees to 20 degrees. 2. The resin has an average particle size of 50 μm or more and 200 or more.
Expanded graphite of less than μm is dispersed, rib and flat plate are integrally formed, and rib height (A) and flat plate thickness (B)
The fuel cell separator according to claim 1, wherein the ratio (A / B) is 2 or more. 3. The fuel cell separator according to claim 1, which has a rib height of 0.5 mm or more. 4. The fuel cell separator according to claim 1, which has a rib height of 1.0 mm or more. 5. The fuel cell separator according to claim 1, wherein the rib is arranged on one side of the flat plate. 6. The fuel cell separator according to claim 1, wherein the ribs are arranged on both sides of the flat plate. 7. The plate thickness of the flat plate is 0.25 mm to 1.0 mm.
The fuel cell separator according to any one of claims 1 to 6. 8. The thickness of the flat plate portion is 0.25 mm to 1.0 m
m, and the ratio of rib height (A) to plate thickness (B) (A
/ B) is 2 or more, The fuel cell separator according to claim 1. 9. The fuel cell is a polymer electrolyte type.
The fuel cell separator according to any one of claims 8 to 10 . 10. A granulated powder obtained by crushing a sheet of expanded graphite preformed, having an average particle size of 50 μm to 200 μm.
A mixture of the following and a thermosetting resin or a thermoplastic resin is used as a raw material, and this is integrally thermocompressed using a mold, and the rib is
A method for producing a ribbed fuel cell separator, characterized in that it has a taper of 2 to 20 degrees . 11. A fuel cell comprising the fuel cell separator according to any one of claims 1 to 9 or obtained by the manufacturing method according to claim 10 . 12. The fuel cell is a polymer electrolyte type.
11. The fuel cell according to item 11 .