JP5797164B2 - Manufacturing method of fuel cell separator - Google Patents

Description

The present invention relates to a method for manufacturing a fuel cell separator used in a low pollution fuel cell having excellent power generation efficiency.

  Although not shown, a conventional fuel cell separator is molded into a thick plate with a predetermined conductive resin composition, laminated and adhered to the electrode assembly, and a cell is formed by sandwiching the electrode assembly in pairs. Configure.

  The predetermined conductive resin composition of the fuel cell separator is prepared from a predetermined resin and a conductive material in order to achieve both strength and conductivity, and graphite or the like is used as the conductive material. Flow grooves for fluid are arranged on both the front and back surfaces of the fuel cell separator, and the plurality of flow grooves distribute fuel gas and cooling water (Patent Documents 1, 2, 3, 4, 5, 6, 7, 8, 9, 10).

JP 2012-025164 A JP 2011-253704 A Japanese Patent Laid-Open No. 2008-041337 JP 2003-331873 A JP 2002-358773 A JP 2002-124276 A JP 2004-273449 A JP 2008-91097 A JP 2006-164659 A JP 2001-338673 A

  By the way, recent fuel cell separators are required to be thin and have high strength in order to realize miniaturization of fuel cells. Particularly in recent automobiles, a thin and high strength fuel cell separator is strongly demanded. However, conventional separators for fuel cells can cope with the increase in thickness and strength, although the predetermined conductive resin composition is simply prepared from the resin and the conductive material. There is a problem that it is difficult to do. In other words, conventionally, when attempting to reduce the thickness while maintaining the conductivity of the fuel cell separator, the strength is insufficient, and the fuel cell separator may be damaged or damaged.

  In order to solve such problems, there have been proposed (1) a method of incorporating a metal plate in a fuel cell separator, and (2) a method of forming the fuel cell separator in a continuous substantially waveform. However, in the case of the method (1), there is a limit to the thinning of the fuel cell separator, and the integration of the fuel cell separator and the metal plate may not be sufficient. In addition, problems such as elution of metal components and weight increase occur. In addition, in the case of the method (2), although it is expected that the thickness and strength of the fuel cell separator will be increased, there is a new problem that the degree of freedom of design is greatly restricted, such as reducing the number of flow grooves. Will occur.

The present invention has been made in view of the above, and it is possible to realize a thin and high-strength separator for a fuel cell, to prevent elution and weight increase of metal components, and to improve the degree of freedom in designing a distribution groove and the like. It aims at providing the manufacturing method of the separator for fuel cells which can be made.

In the present invention, in order to solve the above-mentioned problems, a fuel cell separator manufactured by molding a conductive resin composition with a mold into a thin plate fuel cell separator having a thickness of 1 mm or less that overlaps with an electrode assembly. A manufacturing method comprising:
The mold is composed of a lower mold and an upper mold facing each other, a pattern for the flow groove of the separator for the fuel cell is formed on the cavity surface of the lower mold and the upper mold, and the fuel cell is formed on the cavity surface of the upper mold. Arranging a plurality of punching pins for the distribution port of the separator for
A conductive resin composition is prepared by melting and kneading a thermoplastic resin and artificial graphite having an average particle diameter of 1 μm or more and 500 μm or less and pulverizing, and the composition volume ratio of the thermoplastic resin and the artificial graphite is 50 / 50˜ 15/85 (volume%)
A mold release agent is applied to the mold, and the lower mold is filled with the conductive resin composition. On the conductive resin composition, a carbon fiber cloth having a thickness of 0.1 to 0.6 mm is used. The lower mold is filled with a conductive resin composition that covers the reinforcement, and then the upper mold is clamped to the lower mold and the plurality of punching pins are attached. The fuel cell separator containing the reinforcing material is compression-molded by passing through the communication hole of the reinforcing material and melt-pressing the conductive resin composition to bring the conductive resin composition and the reinforcing material into close contact with each other. A plurality of fluid flow ports are formed in the vicinity of the periphery of the battery separator, and a plurality of fluid flow grooves are formed on both sides of the fuel cell separator.

A plurality of flow grooves on both sides of the fuel cell separator can be made to face each other.

Further, the thermoplastic resin can be a polypropylene resin, a polyphenylene sulfide resin, a polyphenylene sulfide resin, a polyphenyl sulfone resin, or a polyphenyl sulfone resin.

  Here, various fillers that improve moldability, heat resistance, flame retardancy, and the like can be added to the conductive resin composition of the claims as needed. A plurality of reinforcing materials can be incorporated in a fuel cell separator which is a thin plate.

According to the present invention, since a thin and light reinforcing material is incorporated in the fuel cell separator and the material thereof is a carbon fiber cloth, it is possible to reduce the thickness while maintaining the conductivity of the fuel cell separator. The risk of the fuel cell separator being broken or damaged due to insufficient strength can be effectively suppressed. Moreover, it can suppress that a metal component elutes or the weight of the separator for fuel cells increases.

According to the present invention, it is possible to realize a thin and high strength separator for a fuel cell and to effectively solve problems such as elution of metal components and an increase in weight. Moreover, the freedom degree of design of a distribution groove etc. can be improved. Moreover, since the composition volume ratio of the thermoplastic resin and the artificial graphite is in the range of 50/50 to 15/85 (volume%), the conductivity necessary for a fuel cell separator can be obtained, and the conductive resin composition. Thus, the melt fluidity of the conductive resin composition does not deteriorate, the workability or mechanical strength does not decrease, and the conductive resin composition does not easily peel from the reinforcing material. Further, since inexpensive artificial graphite is used, it is excellent in processability and mechanical properties, can be chemically stabilized, has few impurities and elution properties, and can obtain excellent conductivity with high purity.
In addition, since the average particle size of artificial graphite is 1 to 500 μm or less, the carbon-based conductive material rises at the time of work, causing contamination of the work environment, or causing secondary aggregation and lowering the uniform dispersibility with the thermoplastic resin. In addition, the conductivity of the fuel cell separator does not decrease. In addition, the gap between the conductive resin compositions is enlarged, making it difficult to achieve high filling, eliminating the possibility that the contact area with the thermoplastic resin will be reduced and the mechanical properties will be reduced. It is also possible to eliminate the possibility that it becomes difficult to obtain a uniform molded body due to a decrease in the miscibility with graphite. Moreover, since the reinforcing material is made of carbon fiber cloth, the fiber content is increased, the degree of adhesion with the conductive resin composition is increased, and a significant improvement in strength can be expected.
In addition, since the release agent is applied to the mold instead of the conductive resin composition, it is possible to eliminate the possibility that the release agent will not function due to high heat during molding. In addition, since the plurality of punching pins of the upper die are penetrated through the communication holes of the reinforcing material, it is possible to reliably drill a plurality of flow ports in the fuel cell separator. In addition, since a thin fuel cell separator is manufactured by a compression molding method in which the orientation of the conductive resin composition is small, the strength of the fuel cell separator can be improved at low cost with a small capital investment. Furthermore, since the molding pressure directly acts on the fuel cell separator during compression molding, the internal stress of the fuel cell separator can be reduced and deformation can be prevented.

In addition, according to the invention described in claim 2, since it is not necessary to form the fuel cell separator into a continuous waveform having a substantially cross-sectional shape, the degree of freedom in design can be improved .

It is a perspective explanatory view showing typically a fuel cell separator of an embodiment of a manufacturing method of a fuel cell separator concerning the present invention. It is a section explanatory view showing typically the fuel cell separator of the embodiment of the manufacturing method of the fuel cell separator concerning the present invention. It is a section explanatory view showing typically an embodiment of a manufacturing method of a separator for fuel cells concerning the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. A manufacturing method of a fuel cell separator according to the present embodiment includes an electrode assembly called MEA (Mebrane Electrode Assembly) as shown in FIGS. A thin fuel cell separator 1 laminated on a fuel cell separator 1 is molded with a conductive resin composition 4, and a thin reinforcing material 5 is inserted into the center of the fuel cell separator 1 to make it a carbon fiber. The reinforcing member 5 is used to reinforce the fuel cell separator 1 to improve its strength.

  As shown in FIGS. 1 and 2, the fuel cell separator 1 is formed, for example, into a flat rectangular thin plate having a thickness of 1 mm or less using a mold 10 and sandwiches the electrode assembly in a pair. Configure the cell. A plurality of mounting holes and circulation ports 2 are formed in the vicinity of the peripheral edge of the fuel cell separator 1, and the plurality of circulation ports 2 function to circulate air and fuel gas.

  A plurality of fluid flow grooves 3, 3 A are formed in a serpentine shape at locations other than the peripheral portions of the front and back surfaces of the fuel cell separator 1, and the plurality of flow grooves 3, 3 A receive fuel gas and cooling water. Circulate. The plurality of flow grooves 3, 3 A on the front and back surfaces of the fuel cell separator 1 are at least mostly opposed so that the recesses of the flow grooves 3 on the front surface and the recesses of the flow grooves 3 A on the back surface face each other. 3A is partitioned and formed in a substantially U-shaped cross section.

  The conductive resin composition 4 is prepared with a predetermined resin and a carbon-based conductive material, and the composition volume ratio of the resin and the carbon-based conductive material is 50/50 to 15/85 (volume%). The predetermined resin may be either a thermoplastic resin or a thermosetting resin, but is preferably a thermoplastic resin. This is because in the case of a thermosetting resin, it takes a long time to cure, and the productivity cannot be improved. Further, uncured components and reaction products are likely to remain in the fuel cell separator 1, and the residue is eluted during the operation of the fuel cell, leading to a decrease in the durability of the fuel cell. Moreover, since thermosetting resin undergoes curing shrinkage, the design of the mold 10 becomes complicated. Furthermore, although the thermoplastic resin can be recycled, the thermosetting resin cannot be recycled after curing, which increases the product cost and increases the amount of waste.

  Specific thermoplastic resins include, for example, olefin resins (low density polyethylene (LDPE) resin, high density polyethylene (HDPE) resin, very low density polyethylene (VLDPE) resin, linear low density polyethylene (LLDPE) resin, Ultra high molecular weight polyethylene (UHMW-PE) resin, homopolypropylene resin, polypropylene (PP) resin such as block polypropylene resin or random polypropylene resin, polymethylpentene (PMP) resin, cyclic olefin resin, etc.], polystyrene (PS) resin [Atactic polystyrene resin, syndiotactic polystyrene resin, etc.], polyester resin [polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, polytrimethylene naphthalate PTT) resin, polyethylene naphthalate (PEN) resin, polybutylene naphthalate (PBN) resin, or polylactic acid (PLA) resin], polycarbonate (PC) resin, polyamide resin [polyamide 6 resin, polyamide 11 resin, polyamide 12 resin, polyamide 46 resin, polyamide 66 resin, polyamide 610 resin, polyamide 4T resin, polyamide 6T resin, polyamide 9T resin, polyamide 10T resin, etc.], polyarylene (PAR) resin, modified polyphenylene ether resin, fluororesin [tetra Fluoroethylene / ethylene copolymer (ETFE) resin, tetrafluoroethylene / hexafluoropropylene copolymer (FEP) resin, or tetrafluoroethylene / perfluoroalkylvinyltetrafluoroethylene Ren / perfluoroalkyl vinyl ether copolymer (PFA) resin, etc.], polysulfone resin [polysulfone (PSU) resin, polyethersulfone (PES) resin, polyphenylsulfone (PPSU) resin, etc.], polyarylene sulfide type Resin [polyphenylene sulfide (PPS) resin, polyphenylene sulfide sulfone resin, or polyphenylene sulfide ketone resin], liquid crystal polymer, or polyarylene ketone-based resin [polyether ketone (PEK) resin, polyether ketone ketone (PEKK) resin, polyether Ether ketone ketone (PEEKK) resin, etc.], polyimide resin [polyether imide (PEI) resin, polyamide imide (PAI) resin, polyimide (PI) resin, etc.]. It is not limited to that.

  Among these thermoplastic resins, polypropylene (PP) resin is used from the viewpoint of mechanical properties, chemical stability (hydrolysis resistance, solvent resistance), availability, and cost of the fuel cell separator 1. Polyphenylene sulfide (PPS) resin or polyphenylsulfone (PPSU) resin is preferably used. In addition, the thermoplastic resin may be used alone or in combination of two or more, and there is no particular limitation on the shape of powder, granule, lump, granule, pellet or the like. .

  The conductive resin composition 4 is preferably a carbon-based conductive material because it may corrode during use as a fuel cell in the case of a metal-based conductive material. Examples of the carbon-based conductive material include carbon black, carbon nanotube, carbon nanohorn, fullerene, amorphous carbon, carbon fiber, and graphite. Carbon black includes furnace black, channel black, acetylene black, thermal black, and the like.

  As the carbon nanotube, a single-walled carbon nanotube, a multi-walled carbon nanotube, or the like can be used. Further, as the carbon fiber, a PAN-based carbon fiber, a pitch-based carbon fiber, a phenol-based carbon fiber, or a rayon-based carbon fiber can be used. In addition, for graphite, scaled graphite, natural graphite composed of massive graphite, earthy graphite, etc., expanded graphite obtained by chemical treatment of scaled graphite with concentrated sulfuric acid, etc., and then heated, are subjected to heat treatment at high temperature. For example, expanded graphite, artificial graphite, and the like obtained in this manner are applicable.

  Among these carbon-based conductive materials, graphite that is excellent in workability and mechanical properties, chemically stable and inexpensive is most preferable. Among these graphites, artificial graphite is most suitable because it has few impurities and elution properties and can provide excellent conductivity with high purity. Further, the carbon-based conductive material is not particularly limited to powder, granule, lump, and fiber, but a powder that has little mechanical property anisotropy and excellent workability is optimal. Moreover, you may use individually by 1 type and it is also possible to use 2 or more types together.

  The average particle diameter of the carbon-based conductive material is 1 to 500 μm or less, preferably 5 to 300 μm or less, more preferably 10 to 200 μm or less. This is because when the average particle size is less than 1 μm, the carbon-based conductive material rises at the time of work and causes contamination of the work environment, or secondary agglomeration occurs and the uniform dispersibility with the thermoplastic resin is reduced. This is because the conductivity of the battery separator 1 is lowered. Moreover, since the melt fluidity of the conductive resin composition 4 is lowered, it is difficult to mold the thin-walled fuel cell separator 1.

  On the other hand, when the average particle diameter of the carbon-based conductive material exceeds 500 μm, the gap between the conductive resin compositions 4 is enlarged and high filling becomes difficult, and the contact area with the thermoplastic resin is reduced. This is based on the reason that the mechanical characteristics deteriorate. Moreover, it is based on the reason that the mixing property of the thermoplastic resin and the carbon-based conductive material is lowered, and it becomes difficult to obtain a uniform molded body.

  Two or more kinds of carbon-based conductive materials having different particle diameters can be used in combination, and when used in combination, a high packing can be achieved, so that it is possible to obtain a highly conductive fuel cell separator 1. Become. When graphite particles are selected as the carbon-based conductive material, the average particle size of the graphite particles is 5 to 500 μm or less, preferably 10 to 300 μm or less, more preferably 3 to 200 μm or less.

  This is because when the average particle size of the graphite particles is less than 5 μm, the graphite particles soar during the work, the working environment is deteriorated, or secondary agglomeration occurs and the uniform dispersibility with a predetermined resin is reduced, This is based on the reason that the conductivity of the fuel cell separator 1 is lowered. Moreover, since the melt fluidity of the conductive resin composition 4 is lowered, it becomes difficult to form a thin fuel cell separator 1.

  Graphite particles include, for example, silane coupling agents [3-glycidoxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, etc.], titanate cups Ring agents [isopropyl triisostearoyl titanate, tetraisopropyl bis (dioctyl phosphite) titanate, bis (dioctyl pyrophosphate) oxyacetate titanate, isopropyl tri (N-amitoethylaminoethyl) titanate, etc.], aluminate coupling agents [ Various coupling agents such as acetoalkoxyaluminum diisopropylate, etc., surfactants (anionic surfactants, cationic surfactants, amphoteric surfactants, non-ionic surfactants) Sex surfactants, etc.], styrene, can be treated with an organic compound such as acrylic.

  The composition volume ratio between the thermoplastic resin and the carbon-based conductive material is preferably in the range of 50/50 to 15/85 (volume%). This is based on the reason that the conductivity necessary for the fuel cell separator 1 cannot be obtained if it is out of the range. Moreover, when exceeding 85 volume%, the melt fluidity | liquidity of the conductive resin composition 4 falls, and it is based on the reason for causing the fall of workability or the mechanical strength. Furthermore, adhesion between the conductive resin composition 4 and the reinforcing material 5 is insufficient, and the conductive resin composition 4 is easily peeled from the reinforcing material 5.

  In addition to carbon-based conductive materials such as predetermined resins and graphite particles, predetermined additives can be selectively added to the conductive resin composition 4. Examples of the predetermined additive include an antioxidant, a light stabilizer, an ultraviolet absorber, a plasticizer, a lubricant, a flame retardant, an antistatic agent, a heat resistance improver, an inorganic filler, and an organic filler.

  The thermoplastic resin and the carbon-based conductive material of the conductive resin composition 4 are, for example, (1) a method of dispersing and mixing a powdered thermoplastic resin and a carbon-based conductive material at a temperature lower than the melting start temperature of the thermoplastic resin, (2) A method in which a thermoplastic resin and a carbon-based conductive material are melt-kneaded at a temperature equal to or higher than the melting start temperature of the thermoplastic resin and then pulverized after melt-kneading. (3) The thermoplastic resin and the carbon-based conductive material are thermoplastic. A masterbatch is prepared by melt-kneading at a temperature equal to or higher than the melt-kneading temperature of the resin, and this masterbatch is pulverized and mixed with a carbon-based conductive material or prepared by a kneading method.

  These methods are not particularly limited, and any of them can be adopted. However, when a polypropylene resin is employed as the thermoplastic resin, the methods (2) and (3) are preferred because the polypropylene resin alone is difficult to grind.

  The melting start temperature of the methods (1) to (3) differs depending on the type of the predetermined resin. That is, when the predetermined resin is a thermoplastic resin, the melting start temperature is different between a crystalline thermoplastic resin such as polypropylene resin or polyphenylene sulfide resin and an amorphous thermoplastic resin such as polyphenylsulfone resin. The melting start temperature indicates a melting point in the case of a crystalline thermoplastic resin and a glass transition temperature in the case of an amorphous thermoplastic resin.

  When the thermoplastic resin and the carbon-based conductive material are prepared by the method (1), they are mixed and prepared by a stirrer or a ball mill composed of a Nauter mixer, a tumbler mixer, a hensil mixer, a ribbon blender, a V-type mixer, and the like. The The thermoplastic resin and the carbon-based conductive material may have any shape, but the optimum shape varies depending on the molding method of the fuel cell separator 1. For example, when a compression molding method is adopted as the molding method, the anisotropy of mechanical properties and electrical properties can be suppressed, and the mechanical properties and electrical properties within the fuel cell separator 1 are reduced. A powder form that can reduce local variations and is excellent in workability is preferable.

  When the thermoplastic resin and the carbon-based conductive material are prepared by the method (2), various types of kneaders such as a pressure kneader, a flushing kneader, and a KEX kneader, a single screw extruder, a twin screw extruder, a triaxial screw It is melt kneaded by various kneaders such as various extruders such as an extruder and a four-screw extruder, a Banbury mixer and a planetary mixer. However, if necessary, before heat-kneading the thermoplastic resin and the carbon-based conductive material, from the viewpoint of improving dispersibility, a Nauter mixer, tumbler mixer, hensil at a temperature lower than the melting start temperature of the thermoplastic resin. You may stir and mix using mixers, ribbon blenders, stirrers such as V-type mixers, and ball mills.

  In the case of a crystalline thermoplastic resin, the heating and kneading temperature between the thermoplastic resin and the carbon-based conductive material is from the melting start temperature to less than the thermal decomposition temperature, preferably from the melting start temperature + 30 ° C. to the thermal decomposition temperature. In contrast, in the case of an amorphous thermoplastic resin, the melting start temperature is less than the thermal decomposition temperature, preferably the melting start temperature + 50 ° C. to less than the thermal decomposition temperature, more preferably the melting start temperature + 100 ° C. to the thermal decomposition temperature. Is good.

  When the thermoplastic resin and the carbon-based conductive material are prepared by heating and kneading, the conductive resin composition 4 is pulverized and powdered. The pulverization can be performed in one stage, two stages, or a plurality of stages as required. Examples of the pulverization method include a shear pulverization method, an impact pulverization method, a collision pulverization method, a freeze pulverization method, and a solution pulverization method. Among these, the shear pulverization method and the impact pulverization method are optimal from the viewpoint of simplification of the process and cost reduction.

  The pulverization temperature varies depending on the kind of the thermoplastic resin, but usually the temperature lower than the melting start temperature, preferably the melting start temperature of −70 ° C. or lower, preferably the melting start temperature of −100 ° C. or lower is optimal. This is because if the pulverization temperature is equal to or higher than the melting start temperature, the conductive resin composition 4 is softened and cannot be pulverized. In concrete grinding, hammer mills, cutter mills, feather mills, flake crushers, pin mills, impact mills, Victory mills, ball mills, jet mills and other grinding machines, crushers, cutting machines and the like can be used.

  The pulverized conductive resin composition 4 is selectively classified by a classifier such as a sieve mesh, a vibrating mesh, a vibrating screen, an ultrasonic sieve, a micron separator, or a turbo classifier. The conductive resin composition 4 may have any shape, but the optimum shape varies depending on the molding method of the fuel cell separator 1. For example, when the molding method is a compression molding method, the powder form is good as in the case of (1).

  When the thermoplastic resin and the carbon-based conductive material are prepared by the method (3), the addition amount of the carbon-based conductive material is the addition amount of the carbon-based conductive material in the conductive resin composition 4 × 0.5 or more. Further, the addition amount of the carbon-based conductive material in the conductive resin composition 4 is preferably less than 1.0. From the viewpoint of preparing the conductive resin composition 4 having excellent uniform dispersibility, the thermoplastic resin and the carbon conductive resin composition are a Nauter mixer and a tumbler at a temperature lower than the melting start temperature of the thermoplastic resin before melt kneading. It is preferable to mix with a stirrer or a ball mill composed of a mixer, a hensil mixer, a ribbon blender, a V-type mixer or the like. The heating and kneading temperature between the thermoplastic resin and the carbon-based conductive material is the same as in the method (2).

  Masterbatches are various kneaders such as pressure kneaders, flushing kneaders, KEX kneaders, various extruders consisting of single screw extruders, twin screw extruders, triaxial extruders, four screw extruders, Banbury mixers, It is prepared after being melt kneaded and pulverized by a melt kneader such as a planetary mixer.

  For the pulverization, a pulverizer or a cutting machine including a cutter mill, a hammer mill, a spiral mill, a pin mill, a ball mill, an impact mill, a Victory mill, a jet mill, or the like is used. Further, after being pulverized, it is selectively classified by a classifier such as a sieve mesh, a vibrating mesh, a vibrating screen, an ultrasonic sieve, a micron separator, and a turbo classifier. When a carbon-based conductive material is further added to the masterbatch and mixed at a temperature lower than the melting start temperature of the thermoplastic resin, it consists of a Nauter mixer, a tumbler mixer, a hensil mixer, a ribbon blender, a V-type mixer, etc. A stirrer or ball mill is used. About the shape of the prepared conductive resin composition 4, it is the same as that of the case of (1) and (2).

  The fuel cell separator 1 is manufactured by various molding methods. Specific molding methods include a compression molding method, an injection molding method, a transfer molding method, and an injection compression molding method. However, a compression molding method that has little anisotropy in mechanical properties and electrical properties and can be expected to improve dimensional accuracy is optimal. According to this molding method, it is possible to increase the thermoplastic resin and obtain good conductivity while reducing the conductive resin composition 4.

  As shown in FIGS. 2 and 3, the reinforcing member 5 is made of a lightweight thin carbon fiber cloth or the like, and is inserted into the lower mold 11 of the mold 10 when the fuel cell separator 1 is compression-molded. The battery separator 1 is interposed between the plurality of flow grooves 3 and 3A on both the front and back surfaces. The reinforcing material 5 is formed smaller than the fuel cell separator 1 so as not to trigger the peeling off the peripheral surface of the fuel cell separator 1, and corresponds to the plurality of flow ports 2 of the fuel cell separator 1. The communicating hole 6 is formed before or during compression molding of the fuel cell separator 1.

  The material of the reinforcing material 5 is light and thin carbon fiber, glass fiber, alumina fiber, Tyranno fiber, Kevlar fiber, polyethylene fiber, polypropylene fiber, polyester fiber, polyamide fiber, polyarylate fiber PBO (polyparaphenylene benzobisoxazole) Examples thereof include inorganic fibers such as fibers, organic fibers, and nonwoven fabrics. In these, the carbon fiber which can anticipate the improvement of rigidity or intensity | strength, without reducing the electroconductivity of the separator 1 for fuel cells is suitable.

  The reinforcing material 5 can also be used by mixing carbon fibers and other fibers. The form of the carbon fiber can include cloth, felt mat, nonwoven fabric, etc., but from the viewpoint of increasing the fiber content, increasing the adhesion with the conductive resin composition 4, and greatly improving the strength. A cross is preferred.

The cloth is a woven fabric composed of warp and weft, and is preferably a type having a thickness of 0.1 mm to 0.6 mm and a weight of 50 g / m ² to 500 g / m ² . The cloth weave includes plain weave, twill weave, satin weave, etc., but is not particularly limited. There are various types of carbon fiber cloth knitting methods such as twill weave and satin weave, but a strong plain weave that is difficult to break is preferable.

  Specific carbon fiber cloth is not particularly limited. For example, trading card cloth (trade name) manufactured by Toray Co., Ltd., pyrofil fabric (cross) (trade name manufactured by Mitsubishi Rayon Co., Ltd.), tenax fabric (manufactured by Toho Tenax Co., Ltd.) Product name) and diamond lead (product name: manufactured by Mitsubishi Plastics).

  In the above, when manufacturing the fuel cell separator 1, first, the conductive resin composition 4 having a composition volume ratio of the thermoplastic resin and the carbon-based conductive material of 50/50 to 15/85 (volume%) is prepared. To do. When the release property of the conductive resin composition 4 is poor, it is preferable to use a release agent. However, when a release agent is simply added to the conductive resin composition 4, the release agent does not function due to high heat during molding. There is a fear. Therefore, it is preferable to apply the release agent uniformly to the mold 10 in advance.

  When the conductive resin composition 4 is prepared, the conductive resin composition 4 is directly filled in the lower mold 11 of the mold 10 to prepare the surface of the conductive resin composition 4, and carbon is placed on the conductive resin composition 4. A reinforcing material 5 made of fiber cloth is introduced and set horizontally, and the lower mold 11 of the mold 10 is directly filled with the conductive resin composition 4 covering the reinforcing material 5 to prepare the surface.

  The mold 10 includes, for example, a lower mold 11 and an upper mold 12 that face each other, and patterns for the flow grooves 3 and 3A are formed on the cavity surfaces of the lower mold 11 and the upper mold 12, respectively. On the cavity surface of the upper mold 12, a plurality of punching pins 13 for the flow port 2 penetrating the communication hole 6 of the reinforcing material 5 are arranged. The mold 10 is preferably preheated to a temperature lower than the melting start temperature of the conductive resin composition 4, preferably to room temperature.

When the lower mold 11 of the mold 10 is filled with a new conductive resin composition 4, the upper mold 12 is clamped to the lower mold 11 of the mold 10 and heated to a predetermined temperature. By melt-pressing, the fuel cell separator 1 containing the reinforcing material 5 is compression-molded. When the mold 10 is heated and pressurized, it is preferably set between a pair of hot plates heated to a predetermined temperature of the compression molding machine. The pressurizing pressure of the mold 10 is required to be 300 kg / cm ² or more.

  The temperature of the mold 10 is not lower than the melting start temperature and lower than the thermal decomposition temperature, preferably from the melting start temperature + 50 ° C. to lower than the thermal decomposition temperature, more preferably the melting start temperature + 70 ° C., regardless of whether the resin is crystalline or amorphous. ~ Less than thermal decomposition temperature is good. Further, the heating and pressing time of the mold 10 may be a time required for a predetermined thermoplastic resin to flow between the carbon fiber cloths of the reinforcing material 5. Specifically, 10 to 80 seconds is sufficient.

  When the mold 10 is heated and pressurized, the thermoplastic resin starts to flow in a temperature range equal to or higher than the melting start temperature of the thermoplastic resin of the conductive resin composition 4, and the warp of the carbon fiber cloth that is the reinforcing material 5 Thermoplastic resin flows between the wefts. Therefore, the thermoplastic resin of the conductive resin composition 4 and the reinforcing material 5 are in close contact with each other, and excellent mechanical strength can be expected. In addition, since the thermoplastic resin is rarely excessively adhered around the carbon-based conductive material, good conductivity can be expected.

  After the fuel cell separator 1 is compression molded, the fuel cell separator 1 can be obtained by pressurizing and cooling the mold 10 and removing the fuel cell separator 1. The method for pressurizing and cooling the mold 10 includes (1) a method of taking out the mold 10 and setting it between a pair of hot plates of another cooled compression molding machine, and (2) a molding machine of the mold 10. And a method of pressure cooling while being set between the pair of hot plates.

  When the thermoplastic resin of the conductive resin composition 4 is a crystalline resin, the mold 10 is cooled to a melting start temperature or lower, preferably a crystallization temperature or lower, more preferably a glass transition point or lower. On the other hand, in the case of an amorphous resin, it is cooled to a melting start temperature or lower, preferably a melting start temperature −100 ° C. or lower, more preferably a melting start temperature −150 ° C. or lower. This is because if the mold 10 is cooled to such a temperature range, the conductivity of the fuel cell separator 1 can be improved, and the warpage and the bending can be reduced.

  However, since the productivity deteriorates due to a decrease in the cooling temperature, the fuel cell separator 1 may be removed from the mold at a high temperature that satisfies the electrical conductivity. Further, when the thermoplastic resin is a crystalline resin, the glass transition point is -30 ° C. or higher to the crystallization temperature or lower. When the thermoplastic resin is an amorphous resin, The warping and bending of the fuel cell separator 1 may be corrected.

The aligning is preferably performed by stacking the fuel cell separator 1 and placing a weight of 0.05 kg / cm ² thereon. Further, the manufactured fuel cell separator 1 can be subjected to surface treatment such as corona treatment, ultraviolet treatment, plasma treatment, flame treatment or blast treatment to improve hydrophilicity.

  According to the above, since the reinforcing material 5 is incorporated in the fuel cell separator 1 and the material thereof is lightweight carbon fiber, the fuel cell separator 1 can be reduced in thickness while maintaining the conductivity. The risk of breakage or damage of the fuel cell separator 1 due to insufficient strength can be effectively eliminated. In addition, since the fuel cell separator 1 is not a thick metal plate but a thin carbon fiber cloth or carbon fiber non-woven fabric is built in, the fuel cell separator 1 can be made thin and light without any obstacles. Problems such as elution of components and increase in weight can also be prevented.

  Further, if the reinforcing material 5 is a carbon fiber cloth, the conductive resin composition 4 permeates into a large number of stitches at the time of molding, so that the fuel cell separator 1 and the reinforcing material 5 are firmly adhered and integrated. Dimensional stability and rigidity can be significantly improved. Further, since the reinforcing material 5 can be expected to increase the thickness and strength, the flow grooves 3 and 3A of the fuel cell separator 1 can be opposed to each other instead of being arranged in a staggered pattern. Therefore, it is not necessary to form the fuel cell separator 1 with a continuous substantially cross-sectional waveform and reduce the flow grooves, and a significant improvement in design flexibility can be expected.

  In the above embodiment, the mold 10 is simply heated and pressurized or pressurized and cooled. However, a heating mechanism such as an electric heater or a cooling mechanism such as a cooling water channel is used from the viewpoint of energy cost measures during these operations. May be. When heating is performed using steam, it is preferable to use superheated steam that can obtain a high temperature at room temperature. Moreover, in the said embodiment, although the communicating hole 6 was previously pierced in the reinforcing material 5 before compression molding, it is not limited to this at all. For example, the communication hole 6 of the reinforcing material 5 can be omitted if the plurality of flow ports 2 can be reliably drilled in the fuel cell separator 1.

Next, examples of the present invention will be described together with comparative examples.
Example 1
First, polypropylene resin which is a thermoplastic resin [manufactured by Prime Polymer Co., Ltd .: trade name: Prime Polypro E200GV] 31.0% by volume, artificial graphite as a carbon-based conductive material [manufactured by Oriental Sangyo Co., Ltd .: trade name: artificial graphite powder AT-No. 5S, average particle diameter: 53.3 μm] 69.0% by volume is charged into a resin container, and a zirconia ball having a diameter of 10 mm is also charged into the resin container, and a lid is attached to the resin container and attached to the tumbler mixer. At the same time, this tumbler mixer was rotated at 23 ° C. for 1 hour to disperse and mix polypropylene resin, artificial graphite and zirconia balls, and then the zirconia balls were taken out to prepare a dispersion mixture.

  When the melting point of the polypropylene resin was measured by differential scanning calorimetry, the melting point of the polypropylene resin was 172 ° C. Since the polypropylene resin is a crystalline resin, the melting point is set as the melting start temperature. The melting start temperature by differential scanning calorimetry is obtained by accurately weighing 10 mg of a thermoplastic resin sample and raising the temperature at a heating rate of 10 ° C./min with a differential scanning calorimeter. Asked.

  Here, the melting point was a temperature showing the maximum endothermic peak in the differential scanning calorimetry curve, and the glass transition point was the intersection of the base line of the differential scanning calorimetry curve and the tangent of the inflection point. As the differential scanning calorimeter, Seiko Electronics Co., Ltd. [trade name PSC220] was used. The average particle size of the artificial graphite powder was measured by a laser diffraction scattering method or a microtrack method.

  Next, the dispersion mixture is put into a pressure kneader heated to 200 ° C. and melt-kneaded for 10 minutes. The melt-kneaded product is taken out from the pressure kneader and cooled to 50 ° C. or less. It was put into a cutter mill provided and pulverized. When the melt-kneaded product was pulverized in this way, the pulverized melt-kneaded product was again put into a pin mill equipped with a punching metal having a diameter of 0.3 mm and pulverized to prepare a conductive resin composition. It was 85.5 micrometers when the average particle diameter of this conductive resin composition was measured by the laser diffraction scattering method or the microtrack method.

Subsequently, a carbon fiber cloth [Mitsubishi, which is a reinforcing material cut into 148 mm × 148 mm on the conductive resin composition, in which a conductive resin composition is uniformly filled in a mold (inside mold size: 150 mm × 150 mm). Made by Rayon Co., Ltd .: Product name Pyrofil, product number TR3110M, weight 200 g / m ² (catalog value), thickness 0.23 mm (catalog value)], and a new conductive resin composition on this carbon fiber cloth The fuel cell separator was compression molded by heating and pressurizing with a pair of upper and lower hot plates of a compression molding machine until the side surface temperature of the mold reached 200 ° C. The temperature of the hot plate of the compression molding machine was adjusted to 250 ° C., and the molding pressure was 600 kg / cm ² with respect to the area of the fuel cell separator.

  When the side temperature of the mold reaches 200 ° C., heat and press for 15 seconds as it is, and then flow cooling water into a pair of upper and lower hot plates until the side temperature of the mold reaches 50 ° C. or lower. After cooling, the fuel cell separator having an outer shape of 150 mm × 150 mm and a thickness of 1 mm was removed from the mold. When the fuel cell separator was manufactured in this manner, the characteristics of the fuel cell separator, that is, mechanical strength and conductivity, were evaluated and summarized in Table 1.

  The mechanical strength of the fuel cell separator was evaluated by bending strength [MPa], and the conductivity was evaluated by volume resistance [mΩ · cm]. The bending strength was evaluated in accordance with JIS7171, using an evaluation test piece cut out from the flat portion of the fuel cell separator. The volume resistance value was measured by a four-terminal four-probe method using an evaluation test piece cut out from the flat portion of the fuel cell separator. A low resistivity meter [manufactured by Mitsubishi Chemical Co., Ltd .: trade name: Loresta GP MCP-T610] was used as a measuring instrument.

Example 2
First, polypropylene resin (made by Nippon Polypropylene, trade name: Novatik MA3U), 33.1% by volume as a thermoplastic resin, and artificial graphite as a carbon-based conductive material (made by Oriental Sangyo Co., Ltd .: trade name, artificial graphite powder) AT-No. 5S, average particle diameter: 53.3 μm] 66.9% by volume, and zirconia balls having a diameter of 10 mm were added as stirring media, and lids were attached.

  After the lid is attached in this manner, the container is mounted on a tumbler mixer and rotated under the conditions of 26 ° C. for 1 hour, and these polypropylene resin, artificial graphite and zirconia balls are dispersed and mixed, and the zirconia balls are taken out and made of polypropylene resin and artificial graphite. A dispersion mixture was prepared. When the melting point of the polypropylene resin was measured by differential scanning calorimetry, the melting point of the polypropylene resin was 169 ° C. Since the polypropylene resin is a crystalline resin, the melting point is set as the melting start temperature.

  Next, the dispersion mixture is put into a pressure kneader heated to 200 ° C. and melt-kneaded for 10 minutes. The melt-kneaded product is taken out from the pressure kneader and cooled to 50 ° C. or less. It was put into a cutter mill provided and pulverized. When the melt-kneaded product was pulverized in this way, the pulverized melt-kneaded product was again put into a pin mill equipped with a φ0.5 mm punching metal and pulverized. The average particle size of the crushed melt-kneaded product was measured and found to be 108.7 μm.

  When the melt-kneaded product is pulverized, artificial graphite [manufactured by Oriental Sangyo Co., Ltd .: trade name artificial graphite powder AT-No. 5S, average particle diameter: 53.3 μm] and φ10 mm zirconia balls were introduced, and lids were attached. Once the lid is attached, the container is attached to a tumbler mixer and rotated under the conditions of 25 ° C. for 1 hour, and after these melt-kneaded materials, artificial graphite, and zirconia balls are dispersed and mixed, the zirconia balls are taken out and a conductive resin composition is obtained. A product was prepared.

Hereinafter, a separator for a fuel cell was produced by the same method as in Example 1, but as a carbon fiber cloth as a reinforcing material, a trade name: W-3161 [manufactured by Toho Tenax Co., Ltd., weight 200 g / m ² (catalog value) , Thickness 0.25 mm (catalog value)]. When the fuel cell separator was manufactured, the characteristics of the fuel cell separator, that is, mechanical strength and conductivity, were evaluated by the same method as in Example 1, and are summarized in Table 1.

Example 3
First, polyphenylene sulfide resin [manufactured by Toray Industries, Inc .: trade name Torelina E2180] which is a thermoplastic resin was pulverized by a freeze pulverization method. The average particle size of the pulverized polyphenyl sulfide resin was measured by a laser diffraction scattering method or a microtrack method, and found to be 57.8 μm.

  When the polyphenylene sulfide resin is pulverized, 32.3% by volume of the polyphenylene sulfide resin and artificial graphite as a carbon-based conductive material [trade name: artificial graphite powder AT-No. 5S, average particle diameter 53.3 μm] was introduced into a resin container, and zirconia balls with a diameter of 10 mm were respectively introduced as a stirring medium, and a lid was attached.

  Once the lid is attached, the container is attached to a tumbler mixer and rotated at 26 ° C. for 1 hour. The polyphenylene sulfide resin, artificial graphite and zirconia balls are dispersed and mixed, and the zirconia balls are taken out to obtain the conductive resin composition. Prepared. When the melting point of the polyphenylene sulfide resin was measured by differential scanning calorimetry, the melting point of the polyphenylene sulfide resin was 280 ° C. Since polyphenylene sulfide resin is a crystalline resin, the melting point was set as the melting start temperature.

Subsequently, a carbon fiber cloth [Mitsubishi, which is a reinforcing material cut into 148 mm × 148 mm on the conductive resin composition, in which a conductive resin composition is uniformly filled in a mold (inside mold size: 150 mm × 150 mm). Manufactured by Rayon Co., Ltd .: trade name Pyrofil, product number TRK101M, weight 400 g / m ² , thickness 0.43 mm], and a conductive resin composition is newly filled on the carbon fiber cloth, and the upper and lower sides of the compression molding machine The fuel cell separator was compression molded by heating and pressurizing with a pair of hot plates until the side surface temperature of the mold reached 350 ° C. The temperature of the hot plate of the compression molding machine was adjusted to 380 ° C., and the molding pressure was 600 kg / cm ² with respect to the area of the fuel cell separator.

  When the side temperature of the mold reaches 350 ° C., heat and press for 30 seconds as it is, and then flow cooling water into a pair of upper and lower hot plates until the side temperature of the mold reaches 50 ° C. or lower. After cooling, the fuel cell separator having an outer shape of 150 mm × 150 mm and a thickness of 1 mm was removed from the mold. When the fuel cell separator was manufactured, the mechanical strength and conductivity of the fuel cell separator were evaluated in the same manner as in Example 1, and are summarized in Table 1.

Example 4
First, in a resin container, 21.7% by volume of the polyphenylene sulfide resin used in Example 3, and scaly graphite as a carbon conductive resin composition [manufactured by Chuetsu Graphite Industry Co., Ltd .: trade name HG-50A, average particle size] 50 μm (catalog value)] was introduced into a resin container, and a zirconia ball having a diameter of 10 mm was added as a stirring medium to attach a lid. After attaching the lid in this way, the container is mounted on a tumbler mixer and rotated under the conditions of 26 ° C. for 1 hour to disperse and mix these polyphenylene sulfide resin, scaly graphite and zirconia balls, and the zirconia balls are taken out to prepare a dispersion mixture. did.

  Next, the dispersion mixture is put into a pressure kneader heated to 320 ° C. and melt-kneaded for 10 minutes. The melt-kneaded product is taken out from the pressure kneader and cooled to 50 ° C. or lower. It was put into a cutter mill provided and pulverized. When the melt-kneaded product was pulverized, the pulverized melt-kneaded product was again put into a pin mill equipped with a punching metal having a diameter of 0.3 mm and pulverized to prepare a conductive resin composition. When the average particle diameter of the conductive resin composition was measured, it was 65.5 μm. The average particle size of the pulverized melt-kneaded product was measured by a laser diffraction scattering method or a microtrack method.

Hereinafter, a fuel cell separator was produced in the same manner as in Example 3, and the mechanical strength and conductivity of the fuel cell separator were evaluated and summarized in Table 1. The carbon fiber cloth which is a reinforcing material is the pyrofil used in Example 1 [manufactured by Mitsubishi Rayon Co., Ltd .: trade name, product number TR3110M, weight 200 g / m ² (catalog value), thickness 0.23 mm (catalog value)] did. The other parts were the same as in Example 1.

Example 5
First, polyphenylsulfone resin [manufactured by BASF: trade name Ultra Zone P3010] was pulverized by a collision pulverization method. The average particle size of the pulverized polyphenylsulfone resin was measured by a laser diffraction scattering method or a microtrack method, and found to be 62.7 μm. When the polyphenylesulphone resin is pulverized, 30.7% by volume of the polyphenylesulphone resin and artificial graphite (made by Orient Sangyo Co., Ltd .: trade name artificial graphite powder AT-No. 5S, average particle size of 53.3 μm] was introduced into a resin container, and zirconia balls having a diameter of 10 mm were added as stirring media, and a lid was attached.

  Once the lid is attached, the container is mounted on a tumbler mixer and rotated at 26 ° C. for 1 hour. These polyphenylsulfone resins, artificial graphite, and zirconia balls are dispersed and mixed, and the zirconia balls are taken out to form a conductive resin composition. A product was prepared. When the glass transition point of the polyphenylsulfone resin was measured by differential scanning calorimetry, the glass transition point was 218 ° C. Since the polyphenylsulfone resin is an amorphous resin, the glass transition point is set as the melting start temperature.

Next, a carbon fiber cloth (manufactured by Mitsubishi Rayon Co., Ltd .: 148 mm × 148 mm cut into 148 mm × 148 mm on the conductive resin composition, in which a conductive resin composition is uniformly filled in a mold (inside mold size: 150 mm × 150 mm). Product name Pyrofil, product number TR3110M, weight 200 g / m ² (catalog value), thickness 0.23 mm (catalog value)], and a new conductive resin composition is filled on this carbon fiber cloth, The fuel cell separator was compression molded by heating and pressurizing with a pair of upper and lower hot plates of a compression molding machine until the side surface temperature of the mold reached 360 ° C. The temperature of the hot plate of the compression molding machine was adjusted to 400 ° C., and the molding pressure was 600 kg / cm ² with respect to the area of the fuel cell separator.

  When the side surface temperature of the mold reaches 360 ° C., heat and press for 60 seconds as it is, and then inject cooling water into a pair of upper and lower hot plates and pressurize until the side surface temperature of the mold reaches 70 ° C. or less. After cooling, the fuel cell separator having an outer shape of 150 mm × 150 mm and a thickness of 1 mm was removed from the mold. After removing the fuel cell separator, the mechanical strength and conductivity of the fuel cell separator were evaluated and summarized in Table 1. The other parts were the same as in Example 1.

Example 6
First, polyphenylsulfone resin [manufactured by BASF: trade name Ultra Zone P3010] 16.4% by volume, artificial graphite as a carbon-based conductive material [manufactured by Oriental Sangyo Co., Ltd .: trade name, artificial graphite powder AT-No. 5S, average particle diameter: 53.3 μm] 83.6% by volume is put into a resin container, and a zirconia ball having a diameter of 10 mm is also put into the resin container, and a lid is attached to the resin container and attached to the tumbler mixer. At the same time, the tumbler mixer was rotated at 23 ° C. for 1 hour to disperse and mix polyphenylsulfone resin, artificial graphite and zirconia balls, and then the zirconia balls were taken out to prepare a dispersion mixture.

  Next, the dispersion mixture is put into a pressure kneader heated to 350 ° C. and melt-kneaded for 10 minutes. The melt-kneaded product is taken out from the pressure kneader and cooled to 50 ° C. or lower. It was put into a cutter mill provided and pulverized. When the melt-kneaded product was pulverized in this way, the pulverized melt-kneaded product was again put into a pin mill equipped with a punching metal having a diameter of 0.3 mm and pulverized to prepare a conductive resin composition. When the average particle diameter of the conductive resin composition was measured, it was 73.5 μm. The average particle size of the pulverized melt-kneaded product was measured by a laser diffraction scattering method or a microtrack method.

Hereinafter, a fuel cell separator was produced in the same manner as in Example 5. The mechanical strength and conductivity of the produced fuel cell separator were evaluated in the same manner as in Example 1, and are summarized in Table 1. For the carbon fiber cloth, the trade name used in Example 2: W-3161 [manufactured by Toho Tenax Co., Ltd., weight 200 g / m ² (catalog value), thickness 0.25 mm (catalog value)] was selected.

Comparative example 1
The conductive resin composition comprising the polypropylene resin and artificial graphite prepared in Example 1 is uniformly filled in a mold (in-mold size: 150 mm × 150 mm) until the side surface temperature of the mold reaches 200 ° C. The fuel cell separator was compression molded by heating and pressing. The temperature of the hot plate of the compression molding machine was 250 ° C., and the molding pressure was 600 kg / cm ² with respect to the area of the fuel cell separator.

  When the side temperature of the mold reaches 200 ° C., heat and press for 30 seconds as it is, and then flow cooling water into a pair of upper and lower hot plates until the side temperature of the mold reaches 50 ° C. or lower. After cooling, the fuel cell separator having an outer shape of 150 mm × 150 mm × 1 mm was removed from the mold.

  When the fuel cell separator was manufactured, the characteristics of the fuel cell separator, that is, mechanical strength and conductivity were evaluated by the same method as in Example 1, and are summarized in Table 2.

Comparative example 2
A dispersion mixture was prepared in the same manner as in Example 1, except that 55.3% by volume of the polypropylene resin used in Example 1 and 44.7% by volume of artificial graphite as a carbon-based conductive material were used. When the dispersion mixture was prepared in this manner, zirconia balls were taken out from the dispersion mixture to prepare a dispersion mixture of polypropylene resin and artificial graphite. When the dispersion mixture was prepared, the average particle size of the dispersion mixture was measured by the laser diffraction scattering method or the microtrack method, and the average particle size was determined to be 104 μm.

Next, a dispersion mixture was prepared into a conductive resin composition by the method of Example 1, and a fuel cell separator was produced by the method of Example 1. At this time, the carbon fiber cloth as the reinforcing material was the pyrofil used in Example 1 [Mitsubishi Rayon Co., Ltd .: trade name, product number TR3110M, weight 200 g / m ² (catalog value), thickness 0.23 mm (catalog value). )] Was selected. When the fuel cell separator was manufactured, the mechanical strength and conductivity of the fuel cell separator were evaluated in the same manner as in Example 1, and are summarized in Table 2.

Comparative example 3
10% by volume of the pulverized polyphenyl sulfide resin of Example 3 and 90% by volume of artificial graphite were prepared into a dispersion mixture by the same method as in Example 3, and this dispersion mixture was prepared according to the method of Example 3 to be a conductive resin composition. A fuel cell separator was produced from the conductive resin composition according to the method of Example 3. The carbon fiber cloth as a reinforcing material is the pyrofil used in Example 1 (manufactured by Mitsubishi Rayon Co., Ltd .: trade name, product number TR3110M, weight 200 g / m ² (catalog value), thickness 0.23 mm (catalog value)). Using.

  When the fuel cell separator was manufactured, the mechanical strength and conductivity of the fuel cell separator were evaluated in the same manner as in Example 1, and are summarized in Table 2.

  According to Examples 1-6, as shown in Table 1, the separator for fuel cells excellent in mechanical strength and conductivity could be obtained. On the other hand, according to Comparative Examples 1 to 3, as shown in Table 2, at least one of the mechanical strength and conductivity of the fuel cell separator deteriorated, and satisfactory results could not be obtained.

The fuel cell separator manufacturing method according to the present invention can be used , for example, in the fields of fuel cell automobiles, home appliances, mobile devices, and the like.

DESCRIPTION OF SYMBOLS 1 Fuel cell separator 3 Flow groove 3A Flow groove 4 Conductive resin composition 5 Reinforcing material 10 Mold 11 Lower mold 12 Upper mold 13 Punching pin

Claims (2)

A fuel cell separator manufacturing method for manufacturing a thin plate fuel cell separator having a thickness of 1 mm or less overlapping an electrode assembly by molding a conductive resin composition with a mold ,
The mold is composed of a lower mold and an upper mold facing each other, a pattern for the flow groove of the separator for the fuel cell is formed on the cavity surface of the lower mold and the upper mold, and the fuel cell is formed on the cavity surface of the upper mold. Arranging a plurality of punching pins for the distribution port of the separator for
A conductive resin composition is prepared by melting and kneading a thermoplastic resin and artificial graphite having an average particle diameter of 1 μm or more and 500 μm or less and pulverizing, and the composition volume ratio of the thermoplastic resin and the artificial graphite is 50 / 50˜ 15/85 (volume%)
A mold release agent is applied to the mold, and the lower mold is filled with the conductive resin composition. On the conductive resin composition, a carbon fiber cloth having a thickness of 0.1 to 0.6 mm is used. The lower mold is filled with a conductive resin composition that covers the reinforcement, and then the upper mold is clamped to the lower mold and the plurality of punching pins are attached. The fuel cell separator containing the reinforcing material is compression-molded by passing through the communication hole of the reinforcing material and melt-pressing the conductive resin composition to bring the conductive resin composition and the reinforcing material into close contact with each other. A fuel cell separator characterized in that a plurality of fluid flow ports are formed in the vicinity of the peripheral edge of the battery separator, and a plurality of fluid flow grooves are formed on both sides of the fuel cell separator. Production method. The method for producing a fuel cell separator according to claim 1, wherein a plurality of flow grooves on both sides of the fuel cell separator are opposed to each other.

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