JP2002184432A - Ribbed separator for fuel cell and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ribbed separator for a fuel cell having a sidewall, etc., of a reactant gas passage with a superior defect resistance in the ribbed separator for the fuel cell composed of a plate body of graphite powder bound with binder and formed with the reactant gas passage groove on the surface and to provide its manufacturing method. SOLUTION: This ribbed separator for the fuel cell is formed of the plate body of the graphite powder bound with the binder, and formed with the reactant gas passage groove having a slope face getting wider toward the surface opening side set to the sidewall and having a large number of parallel parts, at least, in one surface. This manufacturing method for the ribbed separator for the fuel cell is that after binding the graphite powder with the binder, the mixture is filled between a cope and a drag having projecting threads, which have slope faces tapered from the base end parts to the tip part set to sidewalls, formed, at least, on one inner face in such a state as having a large number of parallel parts and the mixture is pressure formed under the heating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ribbed separator for a fuel cell and a method for producing the same, and more particularly, to a plate-like body of graphite powder bound with a binder, and a reactive gas flow on the surface thereof. The present invention relates to a ribbed separator for a fuel cell in which a groove having a large number of parallel portions is formed as a path, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, fuel cells utilizing the reaction between hydrogen and oxygen have attracted attention as power generation systems that respond to resource problems and environmental problems, and their practical use in various fields is being studied. The basic structure of the fuel cell is that the electrolyte is sandwiched between porous positive and negative electrode plates, and gas barrier properties,
It has a structure in which several tens to several hundreds of cells provided with conductive plate-shaped separators are stacked, and typically, a groove having a large number of parallel portions as a reaction gas flow path for hydrogen, air, and the like. There are a ribbed electrode system formed on the separator side surface of each positive and negative electrode plate, a ribbed separator system formed on each separator surface, and the like. The separator is mainly made of graphite powder, phenol resin, etc. It is manufactured by pressure molding under heating.

[0003] However, these fuel cell separators are generally brittle because a large amount of binder cannot be used from the viewpoint of gas barrier properties and conductivity as the separator, and therefore, the ribbed separator is not used. Since the side wall of the groove having a large number of parallel portions as the reaction gas flow path is formed vertically, the front end of the groove on the surface opening side is easily damaged during handling and use, and
Also at the time of pressure molding, there is a problem that the take-out from the molding die is inferior, and the front end on the surface opening side is broken when taking out from the mold after molding.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem in a ribbed separator for a fuel cell in which a groove having a large number of parallel portions as a reaction gas flow path is formed on a surface thereof. Therefore, the present invention relates to a fuel cell ribbed separator having a plate shape of graphite powder bound with a binder and having a reaction gas channel groove formed on a surface thereof. An object of the present invention is to provide a ribbed separator for a fuel cell which is excellent in chipping resistance such as a side wall of a groove, and a method of manufacturing the same.

[0005]

According to the present invention, there is provided a plate-like body of graphite powder bound with a binder, and at least one surface is provided with an inclined surface which becomes wider toward the surface opening side. And, after mixing the fuel cell ribbed separator in which a reaction gas channel groove having a large number of parallel portions is formed, and graphite powder and a binder, the mixture, on at least one inner surface, The fuel cell in which a ridge having an inclined surface tapered from a base end portion toward a tip end portion as a side wall is filled between upper and lower molds provided so as to have a large number of parallel portions, and pressure-molded under heating. And a method for manufacturing a separator with ribs for use.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION A ribbed separator for a fuel cell according to the present invention comprises a plate-like body of graphite powder bound with a binder, and has a reaction gas flow path having a large number of parallel portions on at least one surface. In which grooves are formed.

[0007] The graphite powder is produced by kneading, molding, calcining, or graphitizing, for example, using natural graphite such as flake, granule, lump, earth, or petroleum coke or pitch coke as a main raw material. The flakes, lumps, and the like of artificial graphite, etc., which have been pulverized, if necessary, may be used.

The graphite powder in the present invention preferably has an ash content of 1% or less from the viewpoint of conductivity and the like.
Those having 0.5% or less are particularly preferred. Further, the content of the alkali metal and the alkaline earth metal is preferably 500 ppm or less, particularly preferably 100 ppm or less.

Further, from the viewpoint of surface smoothness when the separator is used, those having a volatile content of 2% or less are preferable, and 1%
The following are particularly preferred. The content of fixed carbon is preferably 98% or more, particularly preferably 99% or more.

Further, the graphite powder in the present invention includes:
In terms of separator performance, etc., the maximum particle size is 1,000μ
m, preferably 500 μm, more preferably 300 μm. Further, from the viewpoint of separator moldability, performance, and the like, it is preferable that fine powder is not contained. Therefore, the average particle size is preferably from 1 to 100 μm, more preferably from 3 to 70 μm,
It is particularly preferably from 5 to 50 μm.

The binder is not particularly limited, and may be a saturated polyester resin, styrene-acrylic resin, styrene resin, polyamide resin, polycarbonate resin, polysulfone resin, polyvinyl chloride resin, polyolefin resin, polyphenylene ether. Resin, polyphenylene sulfide resin, polyvinyl butyral resin, thermoplastic resin such as acrylic resin, fluorine resin, phenoxy resin, urethane resin, and diallyl phthalate resin, phenol resin, epoxy resin, unsaturated polyester resin, melamine resin, urea resin, etc. Resins such as thermosetting resins, natural rubber (isoprene rubber), butadiene rubber, isoprene rubber, chloroprene rubber, styrene butadiene rubber, acrylonitrile butadiene rubber,
Butyl rubber, ethylene propylene rubber, urethane rubber,
Rubbers such as synthetic rubbers such as fluorine rubber and silicon rubber, and thermoplastic elastomers such as styrene-based thermoplastic elastomers, urethane-based thermoplastic elastomers, polyester-based thermoplastic elastomers, polyamide-based thermoplastic elastomers, and polyolefin-based thermoplastic elastomers Is mentioned. Among them, phenol resins such as novolak resins, resol resins, and modified resins thereof, or rubbers such as butadiene rubber, isoprene rubber, styrene butadiene rubber, and butyl rubber are preferable.

Here, the novolak resin is, for example,
Phenol, o-cresol, m-cresol, p-cresol, 2,5-xylenol, 3,5-xylenol, o-ethylphenol, m-ethylphenol, p
-Ethylphenol, propylphenol, n-butylphenol, tert-butylphenol, 1-naphthol, 2-naphthol, 4,4'-biphenyldiol, bisphenol A, pyrocatechol, resorcinol, hydroquinone, pyrogallol, 1,2,4-benzene Triol, at least one of phenols such as phlorogrisinol, under the acid catalyst, for example, aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, furfural, or
A resin obtained by polycondensation with at least one of ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, and a resole resin is prepared in the same manner except that an alkali catalyst is used instead of an acid catalyst in polycondensation of a novolak resin. Is a polycondensed resin.

The phenol resin as the binder in the present invention is preferably a novolak resin.
It is preferable to use a curing agent to cure at the time of pressure molding under heating of the separator. As the curing agent, for example, typically, hexamethylenetetramine, and a methylol group, an alkoxymethyl group, an acetoxy group as a functional group An amino compound having at least two methyl groups or the like, specifically, a melamine derivative such as methoxymethylated melamine;
Benzoguanamine derivatives, glycoluril derivatives, urea resin derivatives, resole resins and the like can be mentioned.
In addition, these curing agents are 5-1 to the total amount with the resin.
It is used in an amount of 0% by weight.

In the ribbed separator for a fuel cell according to the present invention, the amount of the binder is preferably 1 to 60 parts by weight, more preferably 10 to 50 parts by weight, based on 100 parts by weight of the graphite powder.
It is particularly preferred that the amount be parts by weight. When the amount of the binder is less than the above range, the chipping resistance and the like of the side wall of the groove for the reaction gas flow channel on the surface of the plate-shaped separator tend to be inferior. Performance tends to be impaired.

The ribbed separator for a fuel cell according to the present invention is characterized in that the reaction gas flow channel groove having a large number of parallel portions formed on at least one surface has an inclined surface which becomes wider toward the surface opening side. Is required to be a side wall. If the side wall of the groove for the reaction gas channel is not formed as an inclined surface, it becomes difficult to impart fracture resistance to the side wall and the like. The angle of the inclined surface of the side wall in the parallel portion is preferably 1 to 10 degrees.

The ribbed separator for a fuel cell of the present invention further improves the chipping resistance of the side wall and the like by providing a curvature on the surface opening side and / or the bottom side of the side wall of the reaction gas flow channel groove. Can be done. The curvature is preferably at least 0.05R, more preferably at least 0.1, particularly preferably at least 0.2R. However, if the curvature is too large, the function as a ribbed separator for a fuel cell decreases, such as a decrease in airtightness as a reaction gas flow path. Therefore, it is preferably 3R or less, more preferably 2R or less, and particularly preferably. Is 1R or less.

The cross-sectional shape of the reaction gas flow channel groove may be triangular as long as the side wall has an inclined surface.
It is preferably an inverted trapezoidal shape having a bottom surface, and the width on the surface opening side is 0.3 to 5 mm, more preferably 0.3 to 2 mm, and the depth is 0.3 to 5 mm, further 0.3 to 2 mm. It is preferable that the ratio of the projected area on the front opening side to the total projected area is 30 to 80%.

The groove for the reaction gas flow path may be formed, for example, by providing a gas inlet at one end of the plate and a gas outlet at the other end opposite to the other end of the plate. May be formed in such a manner that a large number of gas inlets and outlets are linearly parallel to each other, and one plate having a gas inlet and a gas outlet on one surface of the plate-like body or A plurality may be formed in a meandering shape having parallel portions.

In the meantime, in the case of the meandering shape as in the latter, the angle of the inclined surface of the side wall at the folded portion is
The angle of the inclined surface of the side wall in the parallel portion is preferably equal to or larger than the angle of the inclined surface of the parallel portion, more preferably 1.1 to 4 times the angle of the inclined surface of the parallel portion. The angle is set in a range up to 5 degrees larger than the angle. Further, it is preferable that the folded portion is folded with a radius.

Further, the reaction gas flow channel groove may be formed only on one surface of the plate-like body or may be formed on both surfaces. In the latter case, the position of the groove is matched or shifted. May be formed so that the parallel portions are parallel to each other,
It is preferable that the parallel portions are formed to be orthogonal to each other.

In the fuel cell ribbed separator of the present invention, after mixing the graphite powder and the binder, the mixture is tapered on at least one inner surface from a base end to a front end. It can be manufactured by filling a ridge having the formed inclined surface as a side wall between upper and lower molds provided with a large number of parallel portions, and press-molding under heating.

Here, the graphite powder and the binder are mixed, for example, by mixing both, or further adding a curing agent, a cross-linking agent, or the like, to a tumbler blender, a ribbon blender,
This is done by uniformly mixing with a mixer such as a mold blender, a Henschel mixer, a super mixer, or by mixing and kneading with a kneader such as a single or twin screw extruder, a roll, a Banbury mixer, a kneader, a Brabender and the like. You.

At this time, in order to uniformly mix the graphite powder and the binder, it is preferable to use the binder as a solution or dispersion of an organic solvent after reducing the viscosity thereof, Examples of the organic solvent include alkanes such as butane, pentane, hexane, heptane and octane, cycloalkanes such as cyclopentane, cyclohexane, cycloheptane and cyclooctane, ethanol, propanol, butanol, amyl alcohol, hexanol and heptanol. Alcohols such as octanol, decanol, undecanol, diacetone alcohol, furfuryl alcohol, and benzyl alcohol; cellosolves such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl cellosolve acetate, and ethyl cellosolve acetate; Propylene glycols such as pyrene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol dimethyl ether, acetone, methyl amyl ketone , Cyclohexanone, ketones such as acetophenone, dioxane, ethers such as tetrahydrofuran, butyl acetate, amyl acetate, ethyl butyrate, butyl butyrate, diethyl oxalate,
Esters such as ethyl pyruvate, ethyl-2-hydroxybutyrate, ethyl acetoacetate, methyl lactate, ethyl lactate, methyl 3-methoxypropionate,
Halogenated hydrocarbons such as chloroform, methylene chloride, and tetrachloroethane; aromatic hydrocarbons such as benzene, toluene, xylene, and cresol; and highly polar solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. , In, alcohols,
Or, aromatic hydrocarbons are preferred. The concentration of the binder in the solution or dispersion at that time is preferably 5 to 90% by weight.

Further, the graphite powder in the above-mentioned mixing includes:
It is preferable that the binder is wetted in advance using the organic solvent used for forming the solution or dispersion, and the organic solvent used in this case is the same organic solvent as used in the solution or dispersion of the binder. It is preferable to use Further, it is preferable that a curing agent, a cross-linking agent, and the like are used by adding to the organic solvent wet product of the graphite powder.

When an organic solvent is used in the mixing, it is necessary to heat and dry the mixture in the form of a paste, and the heating temperature at that time is set to a temperature of about 200 ° C. or less. The content of the organic solvent is preferably 1
Dry to a weight percent or less.

The mixture of the graphite powder and the binder or the added curing agent, cross-linking agent or the like is usually agglomerated by the mixing including the heating and drying. , Mixer, jaw crusher, jailry crusher, roll mill, sample mill,
The material is roughly pulverized by a jet mill, a hammer mill, an impeller breaker, or the like so that the maximum particle size is preferably less than 3 mm.

The pulverized product is heated by a compression molding machine or the like under a temperature not lower than the temperature at which the binder is melted but not higher than the temperature at which the binder is decomposed, preferably 50 to 300 ° C, more preferably 100 to 250 ° C. By pressure molding at a pressure of 40 to 400 MPa, more preferably 65 to 300 MPa, the vertical and horizontal lengths are usually 50 to 500 m, respectively.
m, a desired plate-shaped separator having a thickness of about 2 to 10 mm is manufactured. At that time, for example, in the case of using a phenolic resin as a binder, a curing reaction occurs when a curing agent is used in the case of a novolak resin, and without using a curing agent in the case of a resol resin, and a cured product is formed. Becomes When a rubber to which a cross-linking agent is added is used as a binder, a cross-linking reaction occurs and a cross-linked product is formed.

In the method of manufacturing a ribbed separator for a fuel cell according to the present invention, the mixture or the pulverized material is provided on at least one inner surface with an inclined surface tapering from a base end toward a tip end as a side wall. It is indispensable to fill the space between upper and lower molds provided with a large number of projecting ridges in parallel in one direction and press-mold under heat. If the side wall of the ridge on the inner surface of the mold is not formed as an inclined surface, there arises a problem that the tip of the separator side wall is damaged when the separator is taken out of the mold.
The angle of the inclined surface of the side wall at the parallel portion of the ridge on the inner surface of the mold is preferably 1 to 10 degrees.

Further, by providing a curvature at the distal end and / or the base end of the side wall of the ridge on the inner surface of the mold, it is possible to further improve the detachability of the separator from the mold. The curvature is preferably at least 0.05R, more preferably at least 0.1, particularly preferably at least 0.2R,
It is preferably at most 3R, more preferably at most 2R, particularly preferably at most 1R.

The cross-sectional shape of the ridge may be triangular as long as the side wall is an inclined surface, but is preferably a trapezoid having a flat surface at the tip. The width of the end is 0.3 to 2 mm and the height to the tip is 0.3 to 2
mm, and the occupation ratio of the projected area of the base end of the ridge is preferably 30 to 80% of the total projected area.

The ridges on the inner surface of the mold may be, for example, a plurality of ridges provided linearly parallel to each other from one edge of the inner surface of the mold to the other edge facing the same. From one edge of the mold inner surface to the other opposite edge,
One or more continuous ones may be provided in a meandering shape having parallel portions.

In the meantime, in the case of the meandering shape as in the latter case, it is preferable that the angle of the inclined surface of the side wall of the ridge at the folded portion is equal to or larger than the angle of the inclined surface of the side wall of the parallel portion. The angle is more preferably 1.1 to 4 times the angle of the inclined surface in the parallel portion, and is usually set in a range up to 5 degrees larger than the angle of the inclined surface in the parallel portion. Further, it is preferable that the folded portion be folded with a radius.

Further, these ridges may be provided only on one mold inner surface or both mold inner surfaces. In the latter case, the positions of the ridges may be matched or shifted so that the parallel portions are formed. May be provided in parallel with each other, but it is preferable to provide the parallel portions so as to be orthogonal to each other.

In the present invention, the material of the mold is as follows.
There is no particular limitation, for example, iron, stainless steel, cemented carbide and the like are used, and the ridge is a machining method by scanning a cemented carbide tool such as a diamond head, or a copper or carbon shaped metal equivalent to a mold. Inserting the processed electrode in an insulating liquid together with the mold material, applying a voltage, gradually cutting off the inner surface of the mold by electric discharge machining, etc., and then performing finishing by polishing, lapping, etc. In any case, the cutting marks will remain, but the direction of the cutting marks will be more parallel to the direction perpendicular to the direction in which the separator is removed from the mold. It is preferable that they remain.

In any of the methods, the slopes of the ridge side walls and the planes between the ridges on which the processing is performed will have surface roughness due to the processing. According to JIS, the surface roughness of the slope of the ridge side wall is determined in accordance with JIS from the viewpoint of easy removal of the separator from the mold.
The center line average roughness _Ra75 defined in B0601 (: 2001) is 1.6 μm or less, particularly 0.2 μm or less, and / or the maximum height _Rz is 6.3 μm or less.
In particular, the thickness is preferably 0.8 μm or less. The center line surface roughness _Ra75 is preferably set to 0.0001 μm or more.

Accordingly, the surface roughness of the inclined surface of the side wall of the reaction gas flow channel groove of the ribbed separator for a fuel cell according to the present invention is the center line average roughness _Ra75 specified in JIS B0601 (: 2001). Preferably, it is 1.6 μm or less, particularly preferably 0.2 μm or less, and / or the maximum height _Rz is preferably 6.3 μm or less, particularly preferably 0.8 μm or less. The center line surface roughness _Ra75
Is preferably 0.0001 μm or more. Such a surface roughness of the inclined surface enables a smoother flow of the reaction gas.

In the manufacturing method of the present invention, the inner surface of the mold after the formation of the ridge is coated with a fluorine resin, or is electroplated by using a metal such as Ni, Pt, or Au.
Alternatively, it is also possible to further improve the removal property of the separator from the mold by performing a surface treatment by a CVD method or a PVD method.

It is desirable that the ribbed separator for a fuel cell can maintain a constant flow rate of the reaction gas when a large number of separators are stacked to form a reaction gas flow path. It is necessary to make the width of the gas passage groove on the surface opening side and the width on the bottom side, the inclined surface angle of the side wall, the groove depth, the surface roughness of the inclined surface and the bottom surface as uniform as possible in the separator and between the separators. As one index to express this, the variation rate of the cross-sectional area at about 10 points of the reaction gas flow channel in one separator is 5% or less, further 2% or less, particularly 0.5% or less. It is preferable that the variation rate of the average value of each cross-sectional area between a plurality of separators of about 10 points is also 5%.
Hereinafter, it is more preferably 2% or less, particularly preferably 0.5% or less. Then, as one of means for achieving such a variation rate, the cutting processing conditions of the ridge of the mold are programmed in advance so that the variation rate of the cross-sectional area between the ridges becomes an allowable range. And cutting by automatic control.

In the present invention, as described above,
Since the side wall of the groove for the reaction gas flow channel of the separator is an inclined surface, there is no fear that the front end of the groove on the surface opening side may be damaged during handling and use of the separator. Can be taken out of the metal mold after the pressure molding without causing any defects.

[0040]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention.

Example 1 Toluene 1 was added to 500 g of natural graphite powder having an average particle size of 20 μm.
After adding graphite cc to wet the graphite powder by mixing for 5 minutes, 15 g of commercially available natural rubber as a binder was added to toluene 1
A solution dissolved in 50 cc was added, mixed and kneaded in a double-arm kneader for 1 hour, taken out of the kneader, kept at room temperature for 2 hours, and then heated and dried at 70 ° C. for 30 minutes. Subsequently, the obtained lump was pulverized in a mixer for 2 minutes and sieved through a 16-mesh (aperture 1 mm) sieve so that the total amount was 1 mm or less. Is provided in a meandering shape having a parallel portion, the angle of the inclined surface of the side wall at the parallel portion is 5 degrees, and the center line average roughness _Ra75. Is 0.2μm, maximum height _Rz is 0.8μm, 1R curvature is provided at the distal end and the proximal end of the side wall, the width of the proximal end is 1mm, and the height to the distal end is 1mm. A projection having a projected area of the base end portion occupying 50% of the total projected area, a meandering folded portion having a radius, and an angle of an inclined surface of a side wall at the folded portion being 5 degrees is used. , Between the upper and lower molds with parallel parts orthogonal to each other and provided on both inner surfaces And press-molded at a temperature of 200 ° C. under a pressure of 69 MPa for 2 minutes.
After the cooling, the pressure is reduced and the length and width are each 1
A fuel cell separator having a plate shape of 20 mm and a thickness of 5 mm and having a reaction gas flow channel formed on both surfaces with a shape corresponding to the shape of the protrusion on the inner surface of the mold was manufactured. At that time, the separator could be easily taken out of the mold after the pressure molding, and there were no defects in the reaction gas channel grooves on both surfaces.

Example 2 A commercially available styrene-butadiene rubber was used as a binder, and a solution obtained by dissolving 15 g of the styrene-butadiene rubber in 90 cc of toluene was added to the wet graphite powder, except that the wet surface of the graphite powder was used. A fuel cell separator having a reaction gas channel groove was manufactured. At that time, the separator could be easily removed from the mold after the pressure molding, and the grooves for the reaction gas flow passages on both surfaces did not have any defects.

Example 3 In the same manner as in Example 1, except that the angle of the inclined surface of the side wall at the folded portion of the ridge provided on both inner surfaces of the upper and lower molds was 7 degrees, the reaction gas flow was applied to both surfaces. A fuel cell separator having a road groove was manufactured. At that time, the separator could be easily removed from the mold after the pressure molding, and the grooves for the reaction gas flow passages on both surfaces did not have any defects.

Comparative Example 1 In the same manner as in Example 1, except that the side walls of the ridges provided on both inner surfaces of the upper and lower molds were vertical surfaces, a fuel cell having reaction gas flow channels formed on both surfaces was formed. Was manufactured. At that time, it was difficult to remove the separator from the mold after the pressure molding, and a defect occurred in most of the reaction gas flow channel grooves on the surface opening side on both surfaces.

Comparative Example 2 In the same manner as in Example 2, except that the side walls of the ridges provided on both inner surfaces of the upper and lower molds were vertical, fuel cells having reaction gas flow grooves formed on both surfaces were formed. Was manufactured. At that time, it was difficult to remove the separator from the mold after the pressure molding, and a defect occurred in most of the reaction gas flow channel grooves on the surface opening side on both surfaces.

Example 4 The size of the mold was changed and the vertical and horizontal lengths were each 100.
A fuel cell separator having a plate shape of mm, 250 mm, and 3 mm in thickness and having a groove for a reaction gas flow path formed on one surface with a shape corresponding to the shape of the ridge on the inner surface of the mold was manufactured. At that time, the separator could be easily removed from the mold after the pressure molding, and the grooves for the reaction gas flow passages on both surfaces did not have any defects.

[0047]

According to the present invention, according to the present invention, there is provided a ribbed separator for a fuel cell comprising a plate-like body of graphite powder bound with a binder and having a groove for a reactant gas passage formed on a surface thereof. It is possible to provide a ribbed separator for a fuel cell having excellent fracture resistance, such as a side wall of a flow channel groove, and a method of manufacturing the same.

Claims (13)

[Claims] 1. A plate-like body made of graphite powder bound with a binder, and at least one surface has a large number of parallel portions with an inclined surface widened toward a surface opening side as a side wall. A ribbed separator for a fuel cell, wherein a groove for a reaction gas flow path is formed. 2. The fuel cell ribbed separator according to claim 1, wherein a curvature is provided on a surface opening side and / or a bottom side of a side wall of the reaction gas flow channel groove. 3. The fuel cell ribbed separator according to claim 1, wherein the angle of the inclined surface of the side wall in the parallel portion of the reaction gas flow channel groove is 1 to 10 degrees. 4. The surface roughness of the side wall of the groove for the reaction gas channel is:
The center line average roughness _Ra75 specified in JIS B0601 (: 2001) is 1.6 μm or less, and / or the maximum height _Rz is 6.3 μm or less. 4. The separator with ribs for a fuel cell according to item 1. 5. The ribbed separator for a fuel cell according to claim 1, wherein the cross-sectional shape of the reaction gas flow channel groove is an inverted trapezoidal shape having a bottom surface. 6. The reaction gas flow channel groove has a width on the surface opening side of 0.3 to 5 mm and a depth of 0.3 to 5 mm.
6. The separator with ribs for a fuel cell according to any one of claims 1 to 5. 7. The fuel cell rib according to claim 1, wherein the ratio of the projected area of the reaction gas flow channel groove on the surface opening side to the total projected area is 30 to 80%. With separator. 8. The reaction gas flow channel according to claim 1, wherein a plurality of reaction gas flow grooves having a gas inlet and a gas outlet on one surface of the plate are formed in parallel to each other in a straight line. The ribbed separator for a fuel cell according to any one of the above. 9. The reaction gas flow channel groove is formed in a meandering shape having one or a plurality of parallel portions having a gas inlet and a gas outlet on one surface of the plate-like body. 8. The ribbed separator for a fuel cell according to any one of claims 7 to 7. 10. The angle of the inclined surface of the side wall in the folded portion of the reaction gas flow channel groove formed in a meandering shape is equal to or larger than the angle of the inclined surface of the side wall in the parallel portion. Separator with ribs for fuel cells. 11. The ribbed separator for a fuel cell according to claim 1, wherein the reaction gas flow channel grooves are formed on both surfaces of the plate-like body with parallel portions orthogonal to each other. 12. After the graphite powder and the binder are mixed, the mixture is provided on at least one inner surface with a plurality of ridges each having an inclined surface tapering from a base end toward a tip end as a side wall. The method for producing a ribbed separator for a fuel cell according to any one of claims 1 to 11, wherein the space between the upper and lower molds provided so as to have the parallel portions is filled and pressure-formed under heating. 13. The surface roughness of the slope of the side wall of the ridge is J
The center line average roughness _Ra75 specified in IS B0601 (: 2001) is 1.6 μm or less, and / or
The method for producing a ribbed separator for a fuel cell according to claim 12, wherein the maximum height _Rz is 6.3 µm or less.