WO2012144390A1 - Procédé de fabrication de séparateur de pile à combustible, séparateur de pile à combustible fabriqué par ledit procédé, et matrice de moulage par compression de fabrication de séparateur de pile à combustible utilisée dans ledit procédé - Google Patents

Procédé de fabrication de séparateur de pile à combustible, séparateur de pile à combustible fabriqué par ledit procédé, et matrice de moulage par compression de fabrication de séparateur de pile à combustible utilisée dans ledit procédé Download PDF

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Publication number
WO2012144390A1
WO2012144390A1 PCT/JP2012/059926 JP2012059926W WO2012144390A1 WO 2012144390 A1 WO2012144390 A1 WO 2012144390A1 JP 2012059926 W JP2012059926 W JP 2012059926W WO 2012144390 A1 WO2012144390 A1 WO 2012144390A1
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Prior art keywords
separator
fuel cell
molding
molding material
molded body
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PCT/JP2012/059926
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English (en)
Japanese (ja)
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伊藤　亨
山本　広志
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パナソニック株式会社
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Publication of WO2012144390A1 publication Critical patent/WO2012144390A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0204—Non-porous and characterised by the material
    • H01M8/0223—Composites
    • H01M8/0226—Composites in the form of mixtures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0204—Non-porous and characterised by the material
    • H01M8/0213—Gas-impermeable carbon-containing materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0204—Non-porous and characterised by the material
    • H01M8/0221—Organic resins; Organic polymers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to a method for producing a fuel cell separator, a fuel cell separator produced by the method, and a compression mold for producing a fuel cell separator used in the method.
  • a fuel cell is composed of a cell stack formed by stacking several tens to several hundreds of single cells in series, thereby generating an electromotive force.
  • Fuel cells are classified into several types according to the type of electrolyte. Recently, solid polymer fuel cells using a solid polymer electrolyte membrane as an electrolyte have attracted attention as high-power fuel cells.
  • a single cell of a polymer electrolyte fuel cell is configured by stacking a separator, a gasket, and a membrane-electrode composite (see FIG. 5).
  • a separator In the separator, a fuel manifold, an oxidant manifold, and a cooling manifold are formed in an outer peripheral portion surrounding a region where a gas supply / discharge groove is formed.
  • a gasket for sealing is laminated on the outer peripheral portion of the separator.
  • the fuel cell separator is formed of a metal plate or a molding material containing graphite particles and a resin component.
  • fuel cell separators formed from molding materials containing graphite particles and resin components have been developed in recent years due to their high durability and high degree of freedom in the shape of grooves when forming grooves. Is progressing.
  • a compression molding method or the like is employed in order to form a fuel cell separator from a molding material containing graphite particles and a resin component.
  • Patent Document 1 as a mold for producing a large number of fuel cell separators, at least two fuel cell separator forming space portions are isolated from each other, and a surplus is provided around each separator forming space portion. A mold in which a material reservoir space is formed is disclosed. In the technique disclosed in Patent Document 1, a large number of fuel cell separators are manufactured at a time.
  • Patent Document 1 since a plurality of fuel cell separator forming spaces are isolated, a molding material must be supplied to each of the fuel cell separator forming spaces. Otherwise, it becomes difficult for the molding material to spread in each fuel cell separator forming space. For this reason, the trouble at the time of supplying a molding material will become large. For this reason, the manufacturing efficiency of the fuel cell separator is not sufficiently improved.
  • the present invention has been made in view of the above reasons, and a method for producing a fuel cell separator capable of improving the production efficiency of a fuel cell separator, a fuel cell separator produced by the method, and the method It is an object of the present invention to provide a compression mold for producing a fuel cell separator to be used.
  • a molding material containing graphite particles and a resin component wherein the ratio of the graphite particles is in the range of 70 to 80% by mass;
  • Forming a molded body by compression molding the molding material A plurality of fuel cell separators are cut out from the molded body by cutting the molded body.
  • the disk flow of the molding material is preferably 80 mm or more.
  • Compression molding the molding material using a compression mold in which a plurality of molding spaces matching the shape of the fuel cell separator and a plurality of communication spaces communicating with the molding spaces are formed. Is preferred.
  • the fuel cell separator according to the present invention is manufactured by the above method.
  • a plurality of molding spaces matching the shape of the fuel cell separator and a plurality of communication spaces communicating with the plurality of molding spaces are formed inside.
  • the manufacturing efficiency of the fuel cell separator is improved, and in particular, the manufacturing efficiency of a small fuel cell separator is improved.
  • (A) And (b) is sectional drawing which shows the compression molding process using this metal mold
  • FIG. 5 shows an example of a single cell structure of a polymer electrolyte fuel cell including the separator 20.
  • a membrane-electrode assembly (MEA) 5 comprising an electrolyte 4 such as a solid polymer electrolyte membrane and a gas diffusion electrode (fuel electrode 31 and oxidant electrode 32) is interposed between the two separators 20 and 20.
  • a unit cell unit cell
  • a gasket 12 is interposed between the separator 20 and the electrolyte 4 of the membrane-electrode assembly 5.
  • a battery body (cell stack) is formed by arranging several tens to several hundreds of unit cells.
  • the separator 20 is formed with a gas supply / discharge groove 2 which is a flow path for hydrogen gas or the like as fuel and oxygen gas or the like as an oxidant.
  • the separator 20 is composed of an anode separator having a gas supply / discharge groove 2 only on one side, and a cathode side separator having a gas supply / discharge groove 2 only on one side opposite to the anode separator. Also good.
  • a separator 20 having gas supply / discharge grooves 2 on both sides as shown in FIG. 5 is configured.
  • a channel through which cooling water flows may be formed between the anode side separator and the cathode side separator.
  • a gasket is preferably interposed between the anode side separator and the cathode side separator.
  • a manifold 13 including holes penetrating the separator 20 is formed on the outer peripheral portion of the separator 20 surrounding the region where the gas supply / discharge groove 2 is formed.
  • the separator 20 has six manifolds 13 (two fuel manifolds 131, two oxidant manifolds 132, and two cooling manifolds 133). Two fuel manifolds 131 and 131 are formed. Each of the fuel manifolds 131 communicates with both ends of the gas supply / discharge groove 2 on the surface of the separator 20 that overlaps the fuel electrode 31. Two oxidant manifolds 132 are also formed.
  • Each of the oxidant manifolds 132 communicates with both ends of the gas supply / discharge groove 2 on the surface of the separator 20 overlapping the oxidant electrode 32.
  • Two cooling manifolds 133 are also formed on the outer peripheral portion.
  • the cooling manifold 133 communicates with a flow path through which cooling water between the anode-side separator and the cathode-side separator flows.
  • the separator 20 is formed with a straight type gas supply / discharge groove 2.
  • the gas supply / discharge groove 2 in the separator 20 includes a serpentine type groove having a bend and a straight type groove having no bend.
  • a serpentine type gas supply / discharge groove 2 may be formed in the separator 20.
  • the dimensions of the separator 20 are set as appropriate, but from the viewpoint of obtaining a small separator 20, the thickness is preferably in the range of 0.8 to 3.0 mm, more preferably 0.8 to 2.5 mm.
  • the size of the separator 20 in plan view is preferably in the range of 15 to 250 cm 2 .
  • the width of the gas supply / discharge groove 2 of the separator 20 is, for example, 0.5 to 1.5 mm, and the depth is, for example, 0.5 to 1.5 mm.
  • the opening area of the manifold 13 is formed in the range of 0.5 to 5.0 cm 2 , for example.
  • the gasket 12 is laminated on the outer periphery of the separator 20 for sealing.
  • the gasket 12 has an opening 15 for accommodating the fuel electrode 31 or the oxidant electrode 32 in the membrane-electrode assembly 5 at a substantially central portion thereof, and the groove 2 for gas supply / discharge of the separator 20 is formed in the opening 15.
  • the gasket 12 has a fuel through hole 141 at a position on the outer peripheral side of the opening 15 that matches the fuel manifold 131 of the separator 20, and an oxidant through hole 142 at a position that matches the oxidant manifold 132.
  • Cooling through holes 143 are formed at positions that match the cooling manifold 133.
  • the electrolyte 4 in the membrane-electrode assembly 5 also has a fuel through hole 161 at a position that matches the fuel manifold 131 of the separator 20 on the outer peripheral portion thereof, and an oxidant for the position that matches the oxidant manifold 132.
  • Cooling through holes 163 are formed at positions where the through holes 162 coincide with the cooling manifold 133, respectively.
  • the fuel manifold 131 of the separator 20, the fuel through hole 141 of the gasket 12, and the fuel through hole 161 of the electrolyte 4 communicate with each other to supply and discharge fuel to the fuel electrode.
  • a fuel flow path is configured.
  • the oxidant manifold 132 of the separator 20, the oxidant through hole 142 of the gasket 12, and the oxidant through hole 162 of the electrolyte 4 communicate with each other to supply and discharge the oxidant to the oxidant electrode.
  • the oxidizing agent flow path is configured.
  • the cooling manifold 133 of the separator 20, the cooling through hole 143 of the gasket 12, and the cooling through hole 163 of the electrolyte 4 communicate with each other, thereby forming a cooling channel through which cooling water or the like flows.
  • the fuel electrode 31, the oxidant electrode 32, and the electrolyte 4 are formed of known materials corresponding to the type of fuel cell.
  • the fuel electrode 31 and the oxidant electrode 32 are configured by supporting a catalyst on a substrate such as carbon cloth, carbon paper, or carbon felt.
  • the catalyst in the fuel electrode 31 include a platinum catalyst, a platinum / ruthenium catalyst, and a cobalt catalyst.
  • the catalyst in the oxidant electrode 32 include a platinum catalyst and a silver catalyst.
  • the electrolyte 4 is formed of, for example, a proton conductive polymer membrane.
  • the proton conductivity is high, and the electronic conductivity and methanol permeability are high. It is formed from a fluorine resin or the like that is hardly shown.
  • the gasket 12 is, for example, natural rubber, silicone rubber, SIS copolymer, SBS copolymer, SEBS, ethylene-propylene rubber, ethylene-propylene-diene rubber (EPDM), acrylonitrile-butadiene rubber, hydrogenated acrylonitrile-butadiene rubber (HNBR). ), A rubber material selected from chloroprene rubber, acrylic rubber, fluorine rubber, and the like. This rubber material may contain a tackifier.
  • the gasket 12 When laminating the gasket 12 on the separator 20, for example, the gasket 12 previously formed in a sheet shape or a plate shape is bonded to the separator 20 by being bonded or fused.
  • the gasket 12 may be laminated on the separator 20 by molding a material for forming the gasket 12 on the surface of the separator 20.
  • an unvulcanized rubber material is applied to a predetermined position on the surface of the separator 20 by screen printing or the like, and a desired shape is formed on the predetermined position on the surface of the separator 20 by vulcanizing the coating film of the rubber material.
  • the gasket 12 is formed. In the vulcanization, heating, irradiation with radiation such as an electron beam, or other appropriate vulcanization methods are employed.
  • the gasket 12 is easily laminated even on the thin separator 20.
  • the separator 20 is set in a mold, and an unvulcanized rubber material is injected into a predetermined position on the surface of the separator 20 and the rubber material is heated and vulcanized.
  • a gasket 12 having a desired shape may be formed at a predetermined position on the surface of the separator 20.
  • a molding method such as transfer molding, compression molding, injection molding or the like can be employed.
  • the separator 20 is formed from a cured product of a molding material containing a resin component and graphite particles.
  • the molding material preferably does not contain a primary amine and a secondary amine. That is, it is preferable that this molding material does not contain a compound having substituents —NH and —NH 2 . Furthermore, it is preferable that the molding material does not contain a tertiary amine. Thus, if the molding material does not contain an amine, the separator 20 formed from the molding material does not poison the platinum catalyst in the fuel cell, and the electromotive force when the fuel cell is used for a long time. Reduction is suppressed.
  • the resin component contained in the molding composition may be either a thermoplastic resin or a thermosetting resin.
  • thermoplastic resin examples include polyphenylene sulfide resin and polypropylene resin.
  • thermosetting resin contains at least one of an epoxy resin and a thermosetting phenol resin.
  • Epoxy resins and thermosetting phenol resins are excellent in that they have a good melt viscosity and a small amount of impurities, in particular, a small amount of ionic impurities.
  • the content of the epoxy resin and the thermosetting phenol resin with respect to the total amount of the thermosetting resin is preferably in the range of 50 to 100% by mass. It is particularly preferable if the thermosetting resin contains only an epoxy resin, only a thermosetting phenol resin, or only an epoxy resin and a thermosetting phenol resin.
  • the epoxy resin is preferably in a solid form, and its melting point is preferably in the range of 70 to 90 ° C. Thereby, the change of material decreases and the handleability of the molding material at the time of shaping
  • an ortho cresol novolac type epoxy resin a bisphenol type epoxy resin, a biphenyl type epoxy resin, a phenol aralkyl type epoxy resin having a biphenylene skeleton, or the like is preferably used.
  • This ortho-cresol novolac type epoxy resin, bisphenol type epoxy resin, and phenol aralkyl type epoxy resin having a biphenylene skeleton are excellent in that they have a good melt viscosity and a small amount of impurities, and in particular, a small amount of ionic impurities.
  • the epoxy resin is composed only of an ortho cresol novolac type epoxy resin, or at least one selected from an ortho cresol novolac type epoxy resin, a bisphenol type epoxy resin, a biphenyl type epoxy resin, and a phenol aralkyl type epoxy resin having a biphenylene skeleton. It is preferable that the component (it is called 1st component) which becomes.
  • the ortho-cresol novolac type epoxy resin is an essential component, the moldability of the molding material is improved and the heat resistance of the separator 20 is improved. Furthermore, manufacturing costs can be reduced.
  • the proportion of the ortho-cresol novolac type epoxy resin in the first component is preferably in the range of 50 to 100% by mass from the viewpoints of improving the moldability, improving the heat resistance of the separator 20, and reducing the manufacturing cost.
  • a range of 50 to 70% by mass is particularly preferable.
  • At least one of a bisphenol type epoxy resin, a biphenyl type epoxy resin, and a phenol aralkyl type epoxy resin having a biphenylene skeleton is used in combination with the ortho-cresol novolac type epoxy resin.
  • the melt viscosity of the molding material is further reduced, and the toughness can be improved when a thinner separator 20 is produced.
  • the viscosity of the molding material is reduced and the moldability of the molding material is particularly improved.
  • the content of the bisphenol F type epoxy resin in the first component is preferably in the range of 30 to 50% by mass.
  • the content of the biphenyl type epoxy resin in the first component is preferably in the range of 30 to 50% by mass.
  • the proportion of the phenol aralkyl type epoxy resin having a biphenylene skeleton in the first component is preferably in the range of 30 to 50% by mass.
  • the content of the first component with respect to the total amount of the thermosetting resin in the molding material is preferably in the range of 50 to 100% by mass.
  • the first component is contained in the molding material as at least a part of the epoxy resin in the thermosetting resin. That is, the thermosetting resin other than the first component is selected from, for example, an epoxy resin other than the first component, a thermosetting phenol resin, a vinyl ester resin, a polyimide resin, an unsaturated polyester resin, a diallyl phthalate resin, and the like. One or more kinds of resins may be used. However, it is desirable not to use a resin containing an ester bond because it may hydrolyze in an acid resistant environment.
  • a polyimide resin is also suitable as the thermosetting resin in that it contributes to improving the heat resistance and acid resistance of the separator 20.
  • polyimide resin a bismaleimide resin or the like is particularly preferably used, and for example, 4,4-diaminodiphenyl bismaleimide is preferably used.
  • 4,4-diaminodiphenyl bismaleimide is used, the heat resistance of the separator 20 is further improved.
  • thermosetting phenol resin When a thermosetting phenol resin is used, it is particularly preferable to use a phenol resin that undergoes a polymerization reaction by ring-opening polymerization.
  • phenol resins include benzoxazine resins.
  • gas due to dehydration is not generated in the molding process of the molding material, voids are not generated in the molded product, so that a decrease in gas permeability of the separator 20 is suppressed. It is also preferable to use a resol type phenol resin.
  • the resol resin is usually liquid, but since the softening point of the resol type phenol resin can be easily adjusted, a resol type phenol resin having a melting point of 70 to 90 ° C. can be easily obtained.
  • a resol-type phenol resin having a melting point of 70 to 90 ° C. the quality of the molding material is prevented from being changed, and the handling property of the molding material during molding is improved. When this melting point is less than 70 ° C., aggregation tends to occur in the molding material, and the handleability may be lowered.
  • Resins other than epoxy resins and thermosetting phenol resins may be used in combination.
  • one or more kinds of resins selected from polyimide resins, unsaturated polyester resins, diallyl phthalate resins, vinyl ester resins, and the like may be used.
  • a polyimide resin is also suitable as a thermosetting resin in that it contributes to improving the heat resistance and acid resistance of the separator 20.
  • a polyimide resin a bismaleimide resin and the like are particularly preferable, and specific examples thereof include 4,4-diaminodiphenyl bismaleimide. By using such a resin in combination, the heat resistance of the separator 20 can be further improved.
  • the resin component preferably contains a curing agent, and this curing agent preferably contains a phenolic compound.
  • the phenol compound include novolak type phenol resins, cresol novolac type phenol resins, polyfunctional phenol resins, aralkyl-modified phenol resins, and the like.
  • the content of the phenolic compound relative to the total amount of the curing agent is determined depending on the amount of the epoxy resin used. Further, it is particularly preferable that the curing agent is only a phenol compound.
  • a non-amine compound is preferably used as the curing agent.
  • the electrical conductivity of the separator 20 is maintained at a high level, and poisoning of the fuel cell catalyst is suppressed. It is also preferred that no acid anhydride compound is used as the curing agent.
  • an acid anhydride compound is used, the cured product is hydrolyzed in an acidic environment such as a sulfuric acid acidic environment, causing a decrease in the electrical conductivity of the separator 20 or elution of impurities from the separator 20. May increase.
  • the epoxy resin in the thermosetting resin and the phenolic compound in the curing agent have an equivalent ratio of the epoxy resin to the phenolic compound of 0.8 to 1.2. It is preferable to mix
  • Carbonaceous particles are used to reduce the electrical resistivity of the separator 20 and improve the conductivity of the separator 20.
  • the carbonaceous particles are preferably graphite particles. Any graphite particles can be used as long as they exhibit high conductivity.
  • graphite particles obtained by graphitizing carbonaceous materials such as mesocarbon microbeads, graphitized coal-based cokes and petroleum-based cokes, graphite Appropriate materials such as electrodes, processed powders of special carbon materials, natural graphite, quiche graphite, expanded graphite and the like are used. Only one kind of such graphite particles is used, and a plurality of kinds are used in combination.
  • the graphite particles may be either artificial graphite powder or natural graphite powder.
  • Natural graphite powder has the advantage of high conductivity, and artificial graphite powder has the advantage of low anisotropy, although the conductivity is somewhat inferior to that of natural graphite powder.
  • the graphite particles are preferably purified. In this case, since ash and ionic impurities in the graphite particles are low, elution of impurities from the separator 20 is suppressed.
  • the ash content which is an impurity in the graphite particles is preferably 0.05% by mass or less. If the ash content exceeds 0.05% by mass, the characteristics of the fuel cell including the separator 20 may be deteriorated.
  • the average particle size of the graphite particles is preferably in the range of 10 to 100 ⁇ m.
  • the average particle size is 10 ⁇ m or more, the moldability of the molding material is improved, and when the average particle size is 100 ⁇ m or less, the surface smoothness of the separator 20 is improved.
  • the average particle size is preferably 30 ⁇ m or more, and the surface smoothness of the separator 20 is particularly improved so that the arithmetic average height Ra ( In order for JIS B0601: 2001) to be in the range of 0.4 to 1.6 ⁇ m, particularly less than 1.0 ⁇ m, the average particle size is preferably 70 ⁇ m or less.
  • the average particle size is preferably in the range of 30 to 70 ⁇ m.
  • the graphite particles when the thin separator 20 is produced, the graphite particles preferably have a particle size that passes through a 100 mesh sieve (aperture 150 ⁇ m). If the graphite particles contain particles that do not pass through a 100-mesh sieve, graphite particles having a large particle size will be mixed in the molding material, especially when the molding material is molded into a thin sheet. The moldability of the will be reduced.
  • the aspect ratio of the graphite particles is preferably 10 or less. In this case, anisotropy is suppressed in the separator 20 and deformation such as warpage is also suppressed.
  • the flow direction of the molding material at the time of molding in the separator 20 (direction perpendicular to the thickness direction of the separator 20) and the direction perpendicular to the flow direction (thickness of the separator 20).
  • the ratio of the contact resistance with respect to (direction) is preferably 2 or less.
  • the entire graphite particles have particularly two or more particle size distributions, that is, the entire graphite particles are a mixture of two or more particle groups having different average particle diameters.
  • the particle group means an aggregate of a plurality of particles constituting at least a part of the entire graphite particle. It is preferable that the entire graphite particle is a mixture of a particle group having an average particle diameter of 1 to 50 ⁇ m and a particle group having an average particle diameter of 30 to 100 ⁇ m. When graphite particles having such a particle size distribution are used, it is expected that particles having a large particle size have a small surface area, so that the molding material can be kneaded even if the resin component content is small. .
  • the contact between the particles is improved by the particles having a small particle size, and the strength of the separator 20 is also expected to be improved.
  • the density of the separator 20 is improved, the conductivity is improved, the gas impermeability is improved, and the strength is improved. Improvement of performance such as improvement is achieved.
  • the mixing ratio of the particle group having an average particle diameter of 1 to 50 ⁇ m and the particle group having an average particle diameter of 30 to 100 ⁇ m is appropriately adjusted.
  • the mixing mass ratio of the former to the latter is 40:60 to 90:10, particularly 65. : 35 to 85:15 is preferable.
  • the average particle size of the graphite particles is a volume average particle size measured by a laser diffraction / scattering method with a laser diffraction / scattering particle size analyzer (such as Microtrack MT3000II series manufactured by Nikkiso Co., Ltd.).
  • the ratio of the graphite particles in the molding material is preferably in the range of 70 to 80% by mass with respect to the entire solid content in the molding material. That is, the ratio of the graphite particles in the separator 20 is in the range of 70 to 80% by mass with respect to the whole separator 20, and accordingly, the content of the thermosetting resin cured product in the separator 20 is 20 to 30% by mass. A range is preferable.
  • the ratio of the graphite particles is 70% by mass or more, the separator 20 is provided with sufficiently excellent conductivity, and the mechanical strength of the separator 20 is sufficiently improved. Further, when this ratio is 80% by mass or less, sufficiently excellent moldability is imparted to the molding material and sufficiently excellent gas permeability is imparted to the separator 20. More preferably, the proportion of the graphite particles is 75% by mass or more and the proportion of the cured thermosetting resin is 25% by mass or less.
  • the molding material may contain additives such as a curing catalyst, a wax (release agent), and a coupling agent as necessary.
  • a molding material does not contain a primary amine and a secondary amine
  • a non-amine type compound is used.
  • amine-based diaminodiphenylmethane is not preferred because it may poison the fuel cell catalyst.
  • imidazoles when imidazoles are used, chlorine ions are easily released after the molding material is cured, which is not preferable.
  • the weight loss when heated under the conditions of a measurement start temperature of 30 ° C., a heating rate of 10 ° C./min, a holding temperature of 120 ° C., and a holding time of 30 minutes at the holding temperature is 5% or less, and is in the second place.
  • the use of a substituted imidazole having a hydrocarbon group is preferable in that the storage stability of the molding material is improved.
  • the volatility of the solvent when the sheet-like separator 20 is formed from the molding material prepared in a varnish shape, the smoothness of the separator 20 and the like are good. Become.
  • a substituted imidazole having 6 to 17 carbon atoms in the hydrocarbon group at the 2-position is particularly preferably used.
  • Specific examples thereof include 2-undecylimidazole, 2-heptadecylimidazole, 2- Examples include phenylimidazole and 1-benzyl-2-phenylimidazole. Of these, 2-undecylimidazole and 2-heptadecylimidazole are preferred. These compounds are used alone or in combination of two or more.
  • the content of such a substituted imidazole can be adjusted as appropriate, whereby the molding curing time can be adjusted.
  • the content of the substituted imidazole is preferably in the range of 0.5 to 3% by mass with respect to the total amount of the thermosetting resin and the curing agent in the molding material.
  • a phosphorus compound is preferably used as the curing catalyst.
  • a phosphorus compound and the substituted imidazole may be used in combination.
  • An example of a phosphorus compound is triphenylphosphine. When such a phosphorus compound is used, elution of chlorine ions from the separator 20 is suppressed.
  • the molding material preferably contains a compound represented by the following [Chemical Formula 1] as a curing accelerator.
  • the moisture resistance of the separator 20 is improved.
  • the compound represented by the structural formula (1) does not cause a decrease in the glass transition temperature of the separator 20, a decrease in rigidity during heat, a deterioration in continuous formability, and the like. Rather, by using the compound represented by the structural formula [Chemical Formula 1], the glass transition temperature of the separator 20 is increased, the thermal rigidity is improved, and the releasability during molding of the molding composition is improved. The continuous formability can be improved.
  • ionic impurities are hardly eluted from the compound represented by the structural formula [Chemical Formula 1].
  • the compound represented by the structural formula [Chemical Formula 1] elution of ionic impurities from the separator 20 is suppressed, and deterioration in characteristics such as a decrease in starting voltage of the fuel cell due to the elution of impurities is suppressed.
  • the reason why elution of ionic impurities hardly occurs from the compound represented by the structural formula [Chemical Formula 1] is presumably because the acid dissociation constant (pKa) of this compound is small.
  • the ratio of the compound represented by the structural formula [Chemical Formula 1] to the total amount of the curing accelerator is preferably in the range of 20 to 100% by mass. If this proportion is less than 20% by mass, the glass transition temperature (Tg) of the separator 20 may not be sufficiently increased.
  • the content of such a curing catalyst is appropriately adjusted, but is preferably in the range of 0.5 to 3 parts by mass with respect to the epoxy resin in the molding material.
  • the coupling agent is not particularly limited, but it is preferable that aminosilane is not used because the molding material does not contain a primary amine and a secondary amine. If aminosilane is used, the fuel cell catalyst may be poisoned, which is not preferable. It is also preferred that mercaptosilane is not used as a coupling agent. Similarly, when this mercaptosilane is used, the fuel cell catalyst may be poisoned.
  • coupling agents examples include silicon-based silane compounds, titanate-based, and aluminum-based coupling agents.
  • epoxy silane is suitable as a silicon-based coupling agent.
  • the amount used is preferably in the range where the solid content of the molding material is 0.5 to 1.5% by mass. In this range, the coupling agent can be sufficiently suppressed from bleeding on the surface of the separator 20.
  • the coupling agent may be previously attached to the surface of the graphite particles by spraying or the like.
  • the addition amount in that case is appropriately set in consideration of the specific surface area of the graphite particles and the coatable area per unit mass of the coupling agent (area that can be coated with the coupling agent).
  • the addition amount of the coupling agent is particularly preferably adjusted so that the total amount of the coatable area of the coupling agent is in the range of 0.5 to 2 times the total surface area of the graphite particles. In this range, the bleeding of the coupling agent on the surface of the separator 20 is sufficiently suppressed, thereby suppressing contamination of the mold surface.
  • the wax is not particularly limited, but an internal mold release agent that can be phase-separated without being incompatible with the thermosetting resin and the curing agent in the molding material at 120 to 190 ° C. is used. preferable.
  • Examples of such an internal mold release agent include at least one selected from polyethylene wax, carnauba wax, and long-chain fatty acid wax.
  • Such an internal release agent is phase-separated from the thermosetting resin and the curing agent in the molding process of the molding material, so that the release property of the separator 20 is improved.
  • the content of the internal mold release agent is appropriately determined according to the ease of releasing the molded body 21 from the mold surface due to the complexity of the shape of the molded body 21, which will be described later, the groove depth, the draft angle, and the like. Although it is set, it is preferably in the range of 0.1 to 2.5 mass% with respect to the total solid content in the molding material. When the content is 0.1% by mass or more, the separator 20 exhibits sufficient releasability at the time of molding the mold, and when the content is 2.5% by mass or less, the hydrophilicity of the separator 20 Is kept high enough.
  • the wax content is more preferably in the range of 0.1 to 1% by mass, and particularly preferably in the range of 0.1 to 0.5% by mass.
  • the sodium content is 5 ppm or less and the chlorine content is 5 ppm or less in terms of mass ratio to the total amount of the molding material.
  • the sodium content is 5 ppm or less and the chlorine content is 5 ppm or less in terms of mass ratio to the total amount of the molding material.
  • the ionicity of each component such as a thermosetting resin, a curing agent, graphite, and other additives constituting the molding material.
  • the sodium content is 5 ppm or less and the chlorine content is 5 ppm or less in terms of mass ratio to each component.
  • the content of ionic impurities is derived based on the amount of ionic impurities in the extracted water containing ionic impurities eluted from the target (molding material, thermosetting resin, etc.).
  • the extraction water is heated in 90 ° C. for 50 hours in a state where the object is put in the ion-exchanged water so that the object has a ratio of 100 ml of ion-exchanged water to 10 g of the object. It can be obtained.
  • Ionic impurities in the extracted water are evaluated by ion chromatography.
  • the amount of ionic impurities in the target is derived by converting the amount of ionic impurities in the extracted water into a mass ratio with respect to the target.
  • the molding material is preferably prepared such that the TOC (total organic carbon) of the separator 20 formed from the molding material is 100 ppm or less.
  • TOC is a solution obtained by putting separator 20 in ion-exchanged water at a ratio of 100 ml of ion-exchanged water with respect to 10 g of mass of separator 20, and heating the ion-exchanged water and separator 20 at 90 ° C. for 50 hours. It is a numerical value measured from Such a TOC can be measured, for example, with a total organic carbon analyzer “TOC-50” manufactured by Shimadzu in accordance with JIS K0102. In the measurement, the CO 2 concentration generated by the combustion of the sample is measured by a non-dispersive infrared gas analysis method, thereby quantifying the carbon concentration in the sample. By measuring the carbon concentration, the organic substance concentration contained in the separator 20 is indirectly measured. When inorganic carbon (IC) and total carbon (TC) in the sample are measured, total organic carbon (TOC) is derived from the difference between total carbon and inorganic carbon (TC-IC).
  • IC inorganic carbon
  • TC total carbon
  • the value of TOC can be reduced by selecting a high-purity component as a component constituting the molding material, adjusting the equivalent ratio of the resin, or performing post-curing treatment at the time of molding.
  • a metal component is mixed as an impurity in the raw material component, and a metal component derived from the raw material component or a metal component mixed during manufacture may be mixed as an impurity in the molding material and the separator 20.
  • a metal component is mixed in the separator 20
  • a metal oxide rust
  • metal ions are desorbed from the metal oxide, thereby reducing the proton conductivity of the electrolyte 4 and the electrolyte. 4 may be decomposed.
  • the corrosion current of the separator 20 increases due to this metal component.
  • a treatment for reducing the content of the metal component is performed on at least one of the raw material component, the molding material, and the separator 20.
  • the content of the metal component of the separator 20 is reduced.
  • at least the molding material is preferably subjected to a treatment for reducing the content of the metal component.
  • An example of a process for reducing the content of the metal component with respect to the raw material component is a process of attracting the metal component in the raw material component using a magnet.
  • the treatment for reducing the content of the metal component, particularly with respect to the graphite particles includes a treatment for washing the graphite particles with a strongly acidic solution having a pH of 2 or less.
  • aqua regia obtained by mixing concentrated nitric acid having a concentration of 69% by mass and concentrated hydrochloric acid having a concentration of 36% by mass in a ratio of 1: 3 by volume ratio, hydrochloric acid having a concentration of 15% by mass or more, At least one selected from sulfuric acid having a concentration of 15% by mass or more and nitric acid having a concentration of 15% by mass or more can be used. In this case, the content of the metal component in the graphite particles is easily reduced.
  • the concentration of the hydrochloric acid water, the sulfuric acid water and the nitric acid water is preferably 30% by mass or less from the viewpoint of operability.
  • the treatment for reducing the content of the metal component for the molding material is similar to the treatment for reducing the content of the metal component for the raw material component, using the magnet for the metal component in the molding material. Examples include a suction process.
  • a molding material is prepared by blending the raw material components as described above, and the separator 20 is obtained by molding the molding material.
  • the molding material is formed into an appropriate shape such as a granular shape or a sheet shape.
  • the raw material components as described above are stirred and mixed with, for example, a stirrer or the like, or further sized with a granulator or the like, whereby the molding material is obtained.
  • the molding material may be in the form of a sheet.
  • a thin separator 20 when a thin separator 20 is produced, it is preferable to use a sheet-shaped molding material.
  • a thin separator 20 having a thickness of, for example, 0.2 to 1.0 mm can be easily obtained, and the thickness accuracy of the separator 20 is increased.
  • a liquid composition containing the raw material components as described above is prepared.
  • the liquid composition contains a solvent as necessary.
  • the solvent for example, polar solvents such as methyl ethyl ketone, methoxypropanol, N, N-dimethylformamide, dimethyl sulfoxide are preferable. Only 1 type may be used for a solvent, or 2 or more types may be used together.
  • the amount of the solvent used is appropriately set in consideration of moldability and the like, but is preferably adjusted so that the viscosity of the liquid composition is in the range of 1000 to 5000 cP.
  • the solvent should just be used as needed, and when the thermosetting resin in a raw material component is a liquid resin, a solvent does not need to be used.
  • the sheet-shaped molding material is obtained by molding the liquid composition into a sheet.
  • the liquid composition is formed into a sheet shape by, for example, casting (progressive) molding, and is dried by heating with casting, or is semi-cured to obtain a sheet-shaped molding material. .
  • This sheet-shaped molding material is formed into an appropriate dimension by cutting (cutting) or punching into a predetermined plane dimension as necessary.
  • a sheet-shaped molding material is formed by a casting method
  • a plurality of types of film thickness adjusting means can be applied.
  • the casting method in which such a plurality of types of film thickness adjusting means are used is realized by using, for example, a multi-coater that has already been put into practical use.
  • a film thickness adjusting means for casting it is preferable to use one or both of a doctor knife and a wire bar together with a slit die.
  • the thickness of the sheet-shaped molding material is preferably 0.05 mm or more, and more preferably 0.1 mm or more.
  • the thickness is preferably 0.5 mm or less, and more preferably 0.3 mm or less.
  • the separator 20 when the thickness of the sheet-shaped molding material is 0.5 mm or less, the separator 20 can be made thinner and lighter, and the cost thereof can be reduced. The residual solvent inside the sheet-shaped molding material when using is effectively suppressed. Further, when the thickness is less than 0.05 mm, the advantage in manufacturing the separator 20 is not sufficiently exhibited, and in consideration of moldability, the thickness is preferably 0.1 mm or more.
  • the disk flow of the molding material is preferably 80 mm or more.
  • the upper limit of the disk flow is not particularly limited, but is preferably 100 mm or less from the viewpoint of suppressing excessive outflow of the molding material from the mold during compression molding.
  • 3 g of a molding material is densely arranged at one place on a flat surface, and a long diameter (longest length) of a molded body formed when this is compressed for 30 seconds under conditions of a temperature of 170 ° C. and a pressure of 5 MPa. Diameter).
  • the disk flow of the molding material can be adjusted as appropriate by changing the composition of the molding material. For example, if the graphite content in the molding material decreases, the disk flow increases, and if the graphite content increases, the disk flow decreases. If the content of the curing accelerator in the molding material decreases, the disk flow increases. If the content of the curing accelerator in the molding material increases, the disk flow decreases. Furthermore, when the types of components in the molding material are appropriately changed, the disk flow increases or decreases accordingly.
  • the separator 20 is obtained by molding the molding material.
  • molding method compression molding is employed.
  • FIG. 1 shows an example of a compression molding die 3 used for manufacturing the separator 20.
  • the compression molding die 3 includes a first template 301 and a second template 302 that face each other.
  • the first template 301 is formed with a plurality of recesses 303 to which a molding material is supplied, and the bottom surfaces of the recesses 303 correspond to the gas supply / discharge grooves 2 formed in the separator 20.
  • a protrusion 304 is formed.
  • the first template 301 is formed with a plurality of through holes 305 that open at the bottom surfaces of the plurality of recesses 303.
  • four concave portions 303 are formed in one first template 301.
  • the four recesses 303 are arranged in two rows and two columns.
  • the compression molding die 3 also includes an ejector pin 306 and an ejector plate 307.
  • An ejector pin 306 is inserted into each of the plurality of through holes in the first template 301.
  • the plurality of ejector pins 306 are connected to the ejector plate 307.
  • protrusions 304 corresponding to the gas supply / discharge grooves 2 formed in the separator 20 are formed in regions facing the respective concave portions 303 of the first mold plate 301. ing. Furthermore, a plurality of convex portions 308 corresponding to the plurality of manifolds 13 of the separator 20 are formed in each of the regions.
  • the separator 20 in which the gas supply / discharge grooves 2 are formed on both sides by compression molding is obtained. It is done.
  • the protrusion 304 is formed on only one of the first template 301 and the second template 302. .
  • Forming space 309 is formed inside the recess 303.
  • Each of the molding spaces 309 and another molding space 309 adjacent to the molding spaces 309 are connected via a communication space 310.
  • the communication space 310 is formed so as to fill a gap between adjacent molding spaces 309, and is formed so as to communicate with all the molding spaces 309. For this reason, when the compression mold 3 is clamped, a plurality of molding spaces 309 and communication spaces communicating with these molding spaces 309 are formed between the first template 301 and the second template 302. A single cavity 311 is formed.
  • the molding space 309 has a shape that matches the shape of the separator 20.
  • the shape and size of the molding space 309 are appropriately set so that the separator 20 having a desired shape and size can be obtained.
  • the thickness of the molding space 309 is preferably in the range of 0.8 to 3.0 mm, and more preferably 0.8 to 2.5 mm.
  • the dimension of the molding space 309 in plan view is preferably in the range of 15 to 250 cm 2 .
  • the thickness of the communication space 310 is preferably smaller than the thickness of the molding space 309. Specifically, the thickness of the communication space 310 is preferably in the range of 0.3 mm to 1.0 mm, and more preferably in the range of 0.3 to 0.8 mm. Further, the width of the communication space 310 (that is, the interval between adjacent molding spaces 309) is not particularly limited, but is preferably in the range of 0.3 to 0.5 mm.
  • the number of molding spaces 309 formed in the compression mold 3 is not particularly limited, but is preferably four or more as in this embodiment in order to improve the productivity of the separator 20. For example, six, eight, nine, or more molding spaces 309 and a communication space 310 that connects these molding spaces 309 to each other may be formed in the compression molding die 3.
  • an appropriate amount of molding material is supplied to a region where the cavity 311 on the first template 301 is formed.
  • a sheet-shaped molding material is used, one sheet-shaped molding material is used according to the thickness of the separator 20 or the like, or a plurality of sheet-shaped molding materials are formed on the first template 301. Molding materials are stacked.
  • the molding material is divided into individual separators 20 as long as the molding material is disposed in a region where the cavity 311 is formed. There is no need to For this reason, it is easy to supply the molding material to the compression mold 3.
  • the first template 301 and the second template 302 are maintained at a moldable temperature.
  • the molding material is compression-molded by clamping the first template 301 and the second template 302 (FIG. 1A). Thereby, the molded body 21 is formed in the cavity 311.
  • the molding conditions are appropriately adjusted according to the composition of the molding material.
  • the molding conditions are a molding temperature of 120 to 190 ° C., a molding pressure of 1 to 40 MPa, and a molding time of 1 to 10 minutes.
  • the molded body 21 is formed in the compression molding die 3 in this manner, the first template 301 and the second template 302 are cooled as necessary, and the first template 301 and the second template 301 are further cooled.
  • the mold plate 302 is opened.
  • the molded body 21 remains on the first template 301.
  • the ejector plate 307 is driven, the ejector pin 306 protrudes from the bottom surface of the recess 303, whereby the molded body 21 is removed from the first template 301.
  • the molded body 21 includes a plurality of (four) portions (separator portions 22) formed in the forming space 309 and a portion (connecting portion 23) formed in the communication space 310.
  • the molded body 21 has a shape in which a plurality of separator portions 22 and connecting portions 23 are connected.
  • a plurality of (four in the present embodiment) separators 20 are cut out from the molded body 21 by cutting the molded body 21.
  • the cutting process is performed by an appropriate method such as laser processing, punching processing, use of a cutter, or router processing.
  • the cutting process is preferably performed by water jet processing.
  • the molded body 21 is efficiently cut and the smoothness of the cut surface is increased.
  • the dust is less likely to be scattered, so that the decrease in hydrophilicity on the separator 20 surface due to the adhesion of the dust to the separator 20 is suppressed.
  • the separator part 22 and the connecting part 23 are separated.
  • the width dimension of the connecting part 23 is small (for example, when the width dimension is in the range of 0.3 to 0.5 mm)
  • the molded body 21 may be cut at the connecting part 23.
  • the connecting portion 23 between the two the adjacent separator portions 22 are separated from each other. Thereby, the separator 20 is cut out from the molded body 21.
  • the separator 20 is preferably subjected to blasting or the like to remove the surface skin layer and adjust the surface roughness of the separator 20.
  • the blasting process is performed on the molded body 21 before the cutting process. That is, the separator 20 may be obtained by cutting the molded body 21 after the molded body 21 is blasted.
  • the separator 20 may be obtained by cutting the molded body 21 after the molded body 21 is blasted.
  • special transport equipment may be required depending on the size of the separator 20.
  • the blasting process can be performed in a state where the molded body 21 is stably held, and the necessity of preparing a special transport facility is reduced.
  • the arithmetic average height Ra (JIS B0601: 2001) of the surface of the separator 20 is preferably adjusted to a range of 0.4 to 1.6 ⁇ m.
  • the corrosion current of the separator 20 is reduced, and the corrosion resistance of the separator 20 is improved.
  • gas leakage at the joint between the separator 20 and the gasket 12 is suppressed. For this reason, it is not necessary to mask the part joined to the gasket 12 in the separator 20 during the wet blasting process, and the production efficiency of the separator 20 is improved. It is difficult for the arithmetic average height Ra to be less than 0.4 ⁇ m, and if this value is greater than 1.6 ⁇ m, the gas leak may not be sufficiently suppressed.
  • the arithmetic average height Ra of the surface of the separator 20 is particularly preferably 1.2 ⁇ m or less. Further, when the arithmetic average height Ra of the surface of the separator 20 is less than 1.0 ⁇ m, the gas leak is particularly suppressed, and even when the fastening force at the time of manufacturing the cell stack is lowered as the separator 20 is thinned, Gas leakage is sufficiently suppressed. As described above, the arithmetic average height Ra of the surface of the separator 20 is preferably 0.4 ⁇ m or more, and more preferably 0.6 ⁇ m or more.
  • the contact resistance on the surface of the separator 20 is preferably 15 m ⁇ cm 2 or less. In this case, the function of the separator 20 for transmitting the electric energy generated by the fuel cell to the outside is maintained at a high level.
  • the separator 20 or the molded body 21 is subjected to a wet blasting process, and in this process, a metal component is attracted by a magnet from a slurry containing abrasive grains such as alumina particles.
  • a metal component is mixed as an impurity in the abrasive grains used in the blasting process, and a metal component may be mixed in the slurry containing the abrasive grains during the blasting process.
  • blasting is performed using a slurry containing such a metal component, the metal component easily adheres to the surface of the separator 20 or the molded body 21.
  • the metal component when the metal component is attracted from the slurry by the magnet as described above and the wet blasting process is performed by the abrasive grains, the metal component hardly adheres to the separator 20 or the molded body 21 during the blasting process. That is, while the skin layer is removed and the surface roughness is adjusted by the wet blast treatment, metal components such as metal foreign matters contained in the abrasive grains in the slurry adhere to the separator 20 or the molded body 21 during the wet blast treatment. It becomes difficult to do.
  • the slurry In the wet blasting process, the slurry is repeatedly used while being circulated, and when the metal component is attracted from the slurry by a magnet or the like during the circulation of the slurry, the metal component is attracted by the magnet from the abrasive grains in the slurry. However, wet blasting is performed by the abrasive grains.
  • the metal component may be attracted by the magnet from the separator 20 or the molded body 21 in the same manner as the treatment for reducing the content of the metal component of the graphite particles.
  • the metal component is attracted from the separator 20 or the molded body 21 by arranging the separator 20 or the molded body 21 between the pair of magnets.
  • the metal component may be removed from the separator 20 or the molded body 21 by an appropriate method other than attraction using a magnet.
  • the resin constituting the separator 20 or the molded body 21 may be dissolved, and in the ultrasonic cleaning, the graphite particles may be detached from the separator 20 or the molded body 21. This is not preferable.
  • the separator 20 or the molded body 21 after the wet blast treatment may be washed with ion exchange water or the like.
  • the degree of adhesion of the metal component was determined by washing the separator 20 with 90 ° C. warm water for 1 hour, and then subjecting the separator 20 to heat drying at 90 ° C. for 1 hour. This is confirmed by observing the surface of the separator 20. If a metal component adheres to the separator 20, a metal oxide (rust) is generated on the surface of the separator 20 by the treatment. Even if the surface of the separator 20 after the treatment is visually observed, it is preferable that the presence of the metal oxide (rust) is not confirmed.
  • no metal oxide larger than 100 ⁇ m in diameter is present on the surface of the separator 20 after the treatment, and it is more preferable if no metal oxide larger than 50 ⁇ m in diameter exists. Further, it is particularly preferable if there is no metal oxide having a diameter larger than 30 ⁇ m.
  • the total amount of Fe, Co, and Ni exposed on the surface of the separator 20 is preferably 0.01 ⁇ g / cm 2 or less. Furthermore, the total amount of Cr, Mn, Fe, Co, Ni, Cu and Zn exposed on the surface of the separator 20 is preferably 0.01 ⁇ g / cm 2 or less.
  • the separator 20 or the molded body 21 is subjected to an atmospheric pressure plasma treatment following the wet blast treatment.
  • an atmospheric pressure plasma treatment following the wet blast treatment.
  • the contaminants are removed from the surface of the separator 20 or the molded body 21 to be in a highly active state, and hydrophilic functional groups such as hydroxyl groups are introduced into the activated surface, so that the separator 20 or the molded body 21 Many hydrophilic functional groups are formed on the surface, which is considered to contribute to the improvement of hydrophilicity.
  • the molded body 21 When the molded body 21 is subjected to a wet blasting process, the molded body 21 is subjected to a cutting process to obtain a separator 20, and then the separator 20 is subjected to an atmospheric pressure plasma process. However, it is preferable that the molded body 21 is subjected to atmospheric pressure plasma treatment. When the atmospheric pressure plasma treatment is performed on the compact 21, labor such as conveyance is reduced as compared with the case of handling a small separator.
  • the separator 20 or the molded body 21 after the wet blast treatment is preferably subjected to a drying treatment prior to the atmospheric pressure plasma treatment.
  • a drying treatment prior to the atmospheric pressure plasma treatment.
  • the separator 20 or the molded body 21 is preferably air-dried by air blow or the like.
  • air blowing is performed with room temperature or warm air as necessary, or air blowing with warm air is additionally performed after air blowing at room temperature.
  • the separator 20 or the molded body 21 is allowed to stand in a desiccator containing a desiccant such as silica gel, and the separator 20 or the molded body 21 is a dryer having a temperature of room temperature or higher (for example, 50 ° C.).
  • a method in which the water is allowed to stand a method in which moisture is removed from the separator 20 or the molded body 21 by a vacuum dryer, or the like may be employed. It is preferable that the separator 20 or the molded body 21 is dried by this drying process until the moisture absorption rate is 0.1% or less.
  • the atmospheric pressure plasma treatment for the separator 20 or the molded body 21 is preferably a remote atmospheric pressure plasma treatment.
  • a processing device is used.
  • the plasma generating gas 7 is supplied to the discharge space 10, the pressure in the discharge space 10 is maintained near atmospheric pressure, and a voltage is applied between the discharge electrodes 6 and 6 to discharge the plasma.
  • plasma is generated in the discharge space 10.
  • a plasma treatment is performed by blowing the gas flow 8 containing the plasma from the blow-out port 9 and spraying it on the separator 20 or the molded body 21.
  • Examples of such a plasma processing apparatus include the APT series manufactured by Sekisui Chemical Co., Ltd., but an appropriate plasma processing apparatus provided by Panasonic Electric Works Co., Ltd., Yamato Material Co., Ltd. or the like may be used. .
  • plasma is sprayed toward the surface of the separator 20 or the molded body 21, so that the inner surface of the gas supply / discharge groove 2 of the separator 20 or the molded body 21 is sufficient. Processing is performed. Further, the separator 20 or the molded body 21 is not directly exposed to the discharge during the plasma treatment, and therefore the separator 20 or the molded body 21 is not easily damaged during the plasma treatment.
  • a direct method (FIG. 5) is performed in which plasma generating gas 7 is supplied around the processing target 11 and discharge is generated by the discharge electrodes 6 and 6 around the processing target 11 to generate plasma. 4) may be employed.
  • a direct method (FIG. 5) is performed in which plasma generating gas 7 is supplied around the processing target 11 and discharge is generated by the discharge electrodes 6 and 6 around the processing target 11 to generate plasma. 4) may be employed.
  • the remote method it is preferable to adopt the remote method.
  • the atmospheric pressure plasma treatment by the remote method can be performed under conditions appropriately set so that desired hydrophilicity can be imparted to the surface of the separator 20 or the molded body 21.
  • the plasma generating gas 7 in this atmospheric pressure plasma treatment is preferably nitrogen gas, and the oxygen content in the nitrogen gas is particularly preferably 2000 ppm or less. In this case, particularly high hydrophilicity is imparted to the separator 20 or the molded body 21 by the atmospheric pressure plasma treatment.
  • this atmospheric pressure plasma treatment is preferably performed under conditions in which the temperature of the separator 20 or the molded body 21 and the ambient temperature are adjusted so that condensation does not occur on the surface of the separator 20 or the molded body 21. In this case, it is possible to suppress the consumption of plasma by water droplets attached to the surface of the separator 20 or the molded body 21 and improve the processing efficiency.
  • the temperature of the separator 20 or the molded body 21 is preferably equal to or higher than the temperature at which condensation does not occur on the surface of the separator 20 or the molded body 21 (dew point temperature), and 70 for stable atmospheric pressure plasma treatment. It is preferable that it is below °C.
  • the temperature of the separator 20 or the molded body 21 and the atmospheric temperature In order to stabilize the atmospheric pressure plasma treatment, it is also important to keep the temperature of the separator 20 or the molded body 21 and the atmospheric temperature constant. In adjusting the atmospheric temperature, the temperature of the plasma unit portion of the plasma processing apparatus is usually adjusted. Depending on the configuration of the plasma processing apparatus, the temperature of the stage that supports the separator 20 or the molded body 21 is adjusted during the plasma processing.
  • the separator 20 or the molded body 21 after the atmospheric pressure plasma treatment may be left in the air as it is, but the surface of the separator 20 or the molded body 21 and water are immersed in water such as ion exchange water. Is preferably contacted. In this case, the hydrophilicity of the surface of the separator 20 or the molded body 21 is further improved. Although the detailed mechanism is not clear, the hydrophilicity of the surface of the separator 20 or the molded body 21 is caused by the adsorption of water molecules on the surface of the separator 20 or the molded body 21 activated by the atmospheric pressure plasma treatment. It is thought to improve.
  • the ratio A / B between the width A and the depth B of the gas supply / discharge groove 2 is preferably 1 or more.
  • the gas flow 8 including the slurry at the time of the wet blasting process and the plasma at the time of the atmospheric pressure plasma process easily reaches the inside of the gas supply / discharge groove 2.
  • the uniformity of the surface treatment is further enhanced, and the inner surface of the gas supply / discharge groove 2 is sufficiently hydrophilic.
  • the upper limit of the value of the ratio A / B is not particularly limited, but in order to form the gas supply / discharge grooves 2 with high density, it is preferably 10 or less in practice.
  • the static contact angle with water on the surface of the separator 20 or the molded body 21 after the treatment is in the range of 0 ° to 50 ° by the surface treatment.
  • the static contact angle is particularly preferably in the range of 0 ° to 10 °, and more preferably in the range of 0 ° to 5 °.
  • the static contact angle with water can be adjusted by appropriately setting the surface treatment conditions. Thereby, sufficiently high hydrophilicity can be imparted to the surface of the separator 20 or the molded body 21.
  • the contact resistance of the surface-treated surface of the separator 20 or the molded body 21 is 15 m ⁇ cm 2 or less by surface treatment. This contact resistance can also be adjusted by appropriately setting the surface treatment conditions. Thereby, the function of the separator 20 for transmitting the electric energy generated by the fuel cell to the outside can be maintained at a high level.
  • FIG. 6 shows an example of a fuel cell 40 (cell stack) composed of a plurality of single cells.
  • the fuel cell 40 communicates with a fuel supply port 171 and a discharge port 172 communicating with the fuel flow channel, an oxidant supply port 181 and a discharge port 182 communicating with the oxidant flow channel, and a cooling flow channel.
  • the fuel cell 40 is operated by supplying a fuel such as hydrogen gas from the fuel supply port 171 of the fuel cell 40 and an oxidant such as oxygen gas from the oxidant supply port 181. While the fuel cell 40 is operating, cooling water is supplied to the fuel cell from the cooling water supply port 191. For this reason, the temperature of the fuel cell is adjusted to an appropriate temperature for operation.
  • a fuel such as hydrogen gas from the fuel supply port 171 of the fuel cell 40
  • an oxidant such as oxygen gas from the oxidant supply port 181.
  • the cooling water pure water is preferably used.
  • the raw material components shown in Table 1 were prepared, and these raw material components were put into a stirring mixer (“5XDMV-rr type” manufactured by Dalton) at a ratio shown in Table 1 and stirred and mixed. Was pulverized to a particle size of 500 ⁇ m or less with a granulator. Thereby, a molding material was obtained.
  • a stirring mixer (“5XDMV-rr type” manufactured by Dalton) at a ratio shown in Table 1 and stirred and mixed.
  • a compression mold 3 having the structure shown in FIG. 1 was prepared.
  • this compression molding die 3 four molding spaces 309 arranged in 2 rows and 2 columns are formed.
  • the dimensions of each forming space 309 are 100 mm ⁇ 100 mm in plan view and 2 mm in thickness, and the dimensions of the communication space 310 are 0.3 mm in width and 0.8 mm in thickness.
  • the molding material was supplied to the compression mold 3 and compression molded under conditions of a mold temperature of 170 ° C., a molding pressure of 35.3 MPa, and a molding time of 2 minutes. Thereby, the molded body 21 was obtained.
  • the surface of the molded body 21 is subjected to a blasting process using a slurry containing alumina particles as abrasive grains using a wet blasting apparatus (model PFE-300T / N) manufactured by Macau Corporation, and then washed with ion-exchanged water. Then, it was further dried with warm air.
  • Table 1 shows the results of measuring the arithmetic average height Ra (JIS B0601: 2001) of the surface of the molded body 21 after this treatment.
  • the compact 21 was subjected to a remote atmospheric pressure plasma treatment.
  • AP-T series manufactured by Sekisui Chemical Co., Ltd. was used as the plasma processing apparatus.
  • the processing conditions are a processing width of 300 mm, a plasma unit number of 1, a sample-electrode distance of 3 mm, a gas species for plasma generation is nitrogen, an oxygen content in the gas of 1000 ppm, a gas flow rate of 150 L / min, a conveyance speed of 0.25 m / min,
  • the processing temperature temperature (temperature of the molded body 21) was 25 ° C. After the atmospheric pressure plasma treatment, the molded body 21 was immersed in ion-exchanged water.
  • the separator 21 was cut to obtain four separators 20.
  • the method shown in Table 1 was adopted in each example.
  • Table 1 water jet machining was performed using ion-exchanged water under conditions of a machining width of 0.3 mm, a water pressure of 300 MPa, and a conveyance speed of 100 mm / s.
  • the router processing was performed under conditions of a drill diameter of 0.3 mm, a rotation speed of 24,000 rpm, and a conveyance speed of 20 mm / s.
  • a separator 20 having dimensions of 100 mm ⁇ 100 mm in plan view and 2.0 mm in thickness was obtained.
  • a gas supply / discharge groove having a length of 50 mm, a width of 1.0 mm, and a depth of 1.0 mm was formed on one surface of the separator 20 during compression molding.
  • Table 1 shows the results of observing the cut surfaces of the separators 20 obtained in the respective examples and visually evaluating the appearance for the presence or absence of abnormalities.
  • Thermosetting resin A Cresol novolak type epoxy resin (“EOCN-1020-75” manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent 199, melting point 75 ° C.)
  • Curing agent A Novolac type phenolic resin (“PSM6200” manufactured by Gunei Chemical Industry Co., Ltd., OH equivalent 105)
  • Curing agent B polyfunctional phenol resin (Maywa Kasei Co., Ltd. “MEH-7500”, OH equivalent 100)
  • Curing accelerator A Triphenylphosphine (“TPP” manufactured by Hokuko Chemical Co., Ltd.)
  • Curing accelerator B a compound represented by the structural formula (1).
  • Graphite particles A average particle diameter 50 ⁇ m, natural graphite.
  • Graphite particles B average particle diameter 50 ⁇ m, artificial graphite.
  • Coupling agent Epoxysilane (“A187” manufactured by Nihon Unicar Co., Ltd.)
  • Wax natural carnauba wax ("H1-100” manufactured by Dainichi Chemical Co., Ltd., melting point 83 ° C)

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  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Composite Materials (AREA)
  • Fuel Cell (AREA)

Abstract

Le but de la présente invention est de fournir un procédé de fabrication de séparateur de pile à combustible capable d'améliorer le rendement de fabrication d'un séparateur de pile à combustible. Le procédé de fabrication de séparateur de pile à combustible selon la présente invention comprend : la préparation d'un matériau de moulage comprenant des particules de graphite et un composant de résine, la proportion des particules de graphite étant dans la plage de 70 à 80 % en masse ; la formation d'un corps moulé par compression et moulage du matériau de moulage ; et la découpe d'une pluralité de séparateurs de pile à combustible à partir du corps moulé par découpe du corps moulé.
PCT/JP2012/059926 2011-04-20 2012-04-11 Procédé de fabrication de séparateur de pile à combustible, séparateur de pile à combustible fabriqué par ledit procédé, et matrice de moulage par compression de fabrication de séparateur de pile à combustible utilisée dans ledit procédé WO2012144390A1 (fr)

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JP2011-094271 2011-04-20
JP2011094271A JP5838341B2 (ja) 2011-04-20 2011-04-20 燃料電池用セパレータの製造方法、前記方法により製造される燃料電池用セパレータ、及び前記方法で使用される燃料電池用セパレータ製造用圧縮成形金型

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WO2012144390A1 true WO2012144390A1 (fr) 2012-10-26

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DE102020006943A1 (de) * 2020-11-12 2022-05-12 Cellcentric Gmbh & Co. Kg Herstellungsverfahren für Komponenten eines Brennstoffzellenstapel

Citations (6)

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JP2003022816A (ja) * 2001-05-31 2003-01-24 General Motors Corp <Gm> 繊維の方向が調整された燃料電池セパレータプレート及び製造方法
JP2004188722A (ja) * 2002-12-10 2004-07-08 Meiki Co Ltd 燃料電池用セパレータの成形方法および成形金型
JP2005302374A (ja) * 2004-04-07 2005-10-27 Meiki Co Ltd 燃料電池用セパレータ成形用金型
JP2006019252A (ja) * 2004-05-31 2006-01-19 Matsushita Electric Ind Co Ltd 高分子電解質形燃料電池用セパレータ、高分子電解質形燃料電池、高分子電解質形燃料電池用セパレータの評価方法、及び、高分子電解質形燃料電池用セパレータの製造方法
JP2006210222A (ja) * 2005-01-31 2006-08-10 Nichias Corp 燃料電池用セパレータ及びその製造方法
JP2006332035A (ja) * 2005-04-25 2006-12-07 Dainippon Ink & Chem Inc 燃料電池用セパレータ、その製造方法及びそれを用いた燃料電池

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Publication number Priority date Publication date Assignee Title
ATE402494T1 (de) * 2005-09-06 2008-08-15 Sgl Carbon Ag Elektroden für brennstoffzellen

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003022816A (ja) * 2001-05-31 2003-01-24 General Motors Corp <Gm> 繊維の方向が調整された燃料電池セパレータプレート及び製造方法
JP2004188722A (ja) * 2002-12-10 2004-07-08 Meiki Co Ltd 燃料電池用セパレータの成形方法および成形金型
JP2005302374A (ja) * 2004-04-07 2005-10-27 Meiki Co Ltd 燃料電池用セパレータ成形用金型
JP2006019252A (ja) * 2004-05-31 2006-01-19 Matsushita Electric Ind Co Ltd 高分子電解質形燃料電池用セパレータ、高分子電解質形燃料電池、高分子電解質形燃料電池用セパレータの評価方法、及び、高分子電解質形燃料電池用セパレータの製造方法
JP2006210222A (ja) * 2005-01-31 2006-08-10 Nichias Corp 燃料電池用セパレータ及びその製造方法
JP2006332035A (ja) * 2005-04-25 2006-12-07 Dainippon Ink & Chem Inc 燃料電池用セパレータ、その製造方法及びそれを用いた燃料電池

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