WO2005064721A1 - Composition destinee a un separateur de pile a combustible et procede de production de celui-ci - Google Patents

Composition destinee a un separateur de pile a combustible et procede de production de celui-ci Download PDF

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Publication number
WO2005064721A1
WO2005064721A1 PCT/JP2004/019031 JP2004019031W WO2005064721A1 WO 2005064721 A1 WO2005064721 A1 WO 2005064721A1 JP 2004019031 W JP2004019031 W JP 2004019031W WO 2005064721 A1 WO2005064721 A1 WO 2005064721A1
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Prior art keywords
epoxy resin
fuel cell
cell separator
composition
graphite
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PCT/JP2004/019031
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English (en)
Japanese (ja)
Inventor
Yasuhiko Watanabe
Hiroshi Ono
Takayuki Kawarada
Masaharu Takehara
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Nippon Steel Chemical Co., Ltd.
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Priority to JP2005516579A priority Critical patent/JPWO2005064721A1/ja
Publication of WO2005064721A1 publication Critical patent/WO2005064721A1/fr

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Classifications

    • 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
    • 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
    • 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

  • Composition for fuel cell separator and method for producing fuel cell separator Composition for fuel cell separator and method for producing fuel cell separator
  • the present invention is applied to a fuel cell separator composition, particularly a polymer electrolyte fuel cell separator, and comprises a graphite and resin-based separator composition, and a fuel cell separator using the composition. And a method for producing the same.
  • Fuel cells for use in automobiles, home cogeneration, and the like are receiving attention.
  • This fuel cell uses chemical energy directly as electrical energy without converting it into thermal energy, and usually refers to a battery that extracts electricity by the reaction of hydrogen and oxygen.
  • fuel cells There are several types of such fuel cells, such as phosphoric acid fuel cells, solid oxide fuel cells, and polymer electrolyte fuel cells (PEFCs).
  • a separator that is a conductive molded product is used.
  • the separator constitutes a unit cell together with electrodes and the like, and is used by stacking the unit cells.
  • the separator needs to have conductivity while isolating gas (hydrogen / oxygen).
  • Patent Document 1 JP-A-4-214072
  • Patent Document 2 JP-A-8-31231
  • Patent Document 3 JP-A-11-195422
  • Patent Document 4 JP-A-11-297338
  • Patent Document 5 JP-A-2000-40517
  • Patent Document 6 JP-A-2000-21421
  • Patent Document 7 Japanese Patent Application Laid-Open No. 2001-139696
  • Patent Document 8 Japanese Patent Application Laid-Open No. 2001-216976
  • Patent Document 9 JP-A-2002-83609
  • Patent Document 10 Japanese Patent Application Laid-Open No. 2002-201257
  • Patent Document 1 in order to obtain a carbon material suitable as a fuel cell separator having a dense and high mechanical strength and excellent conductivity, a carbon material comprising a binder and a plurality of particle sizes is used to obtain a carbon material suitable for a fuel cell separator.
  • a graphite carbon material has been proposed. However, this method requires graphitization after molding.
  • Patent Document 2 in order to obtain a carbon material suitable for a fuel cell separator having a porosity of 5% or less and a ratio of a volume resistivity in the XY direction to a volume resistivity in the Z direction of the molded body of 2 or less.
  • Patent Document 3 proposes a method in which a small amount of a binder is blended with a carbon material, pressure-formed, and then impregnated with an impregnating agent in order to reduce the amount of the binder and improve conductivity.
  • Patent Document 4 proposes a fuel cell separator having a certain range of surface roughness in order to obtain a fuel cell separator having a low contact resistance with an electrode portion.
  • Patent Document 5 proposes that artificial graphite and natural graphite be used together in order to obtain a fuel cell separator with low anisotropy.
  • Patent Document 6 proposes to use a specific graphite powder in order to obtain a fuel cell separator having a good balance of gas impermeability, thermal conductivity, conductivity, and the like.
  • Patent Documents 7 to 10 disclose a conductive epoxy resin molding material containing graphite and epoxy resin.
  • ortho-cresol novolak type epoxy resin or bisphenol type epoxy resin is used as the epoxy resin.
  • the bisphenol type epoxy resin is specifically a bisphenol A type epoxy resin.
  • Patent Document 8 discloses only a bisphenol F-type epoxy resin as an epoxy resin.
  • Patent Documents 9 and 10 disclose that as an epoxy resin, It only discloses a novolak type epoxy resin.
  • an object of the present invention is to provide a molding material that shortens the molding cycle, has excellent dimensional accuracy, and is suitable for mass production of separators in the future. Means for solving the problem
  • the inventors of the present invention have conducted intensive studies to solve such a problem, and as a result, as a resin, an epoxy resin which is solid at normal temperature but exhibits low viscosity at the time of high-temperature melting is graphite at a predetermined ratio.
  • the present inventors have found that the above problems can be solved by blending with a powder, and have completed the present invention.
  • the present invention relates to a composition containing an epoxy resin binder and graphite powder, wherein the weight ratio of the graphite powder to the epoxy resin binder is 2 to 10 times, preferably 3 to 10 times. — Compounded in a 7-fold amount, compound viscosity after kneading graphite powder and epoxy resin binder is 200-3000Pa's, and electrical resistivity is 100m ⁇ cm or less, preferably 40m ⁇ cm or less. This is a fuel cell separator composition.
  • the epoxy resin binder becomes the epoxy resin and the curing agent power
  • the epoxy resin power has a viscosity of 120 mPa's at 150 ° C, a melting point of 45 ° C to 130 ° C, and preferably 50 ° C to 130 ° C.
  • the epoxy resin power may contain one or more crystalline epoxy resins that are solid at room temperature.
  • the present invention provides a composition containing an epoxy resin binder and graphite powder, in which 2 to 10 times, preferably 3 to 7 times, the weight ratio of graphite powder to the epoxy resin binder is blended.
  • the epoxy resin binder is composed of an epoxy resin and a curing agent, and the epoxy resin is crystalline.
  • the viscosity at 150 ° C is 120 mPa's, and the melting point is 45 ° C-130 ° C.
  • Is a composition for a fuel cell separator comprising at least one kind of crystalline epoxy resin which is a solid at 50 ° C. to 130 ° C. and room temperature.
  • the crystalline epoxy resin used for the epoxy resin binder includes the following general formula (1):
  • G represents a glycidyl group
  • R represents a monovalent group
  • n represents an integer of 0-4, and
  • X represents a divalent group
  • it is an ether type epoxy resin or a thioether type epoxy resin wherein X is O or S.
  • the method for producing a fuel cell separator of the present invention comprises kneading, pulverizing, and then molding and curing the pulverized product at a temperature of 100 to 350 ° C, preferably 140 to 230 ° C.
  • the fuel cell separator of the present invention is obtained by a small manufacturing method.
  • the fuel cell separator is provided between adjacent unit cells in a fuel cell configured by stacking a plurality of unit cells, and forms a fuel gas flow path and an oxidizing gas flow path with an electrode. And has a function to separate the gas from the oxidizing gas, and a groove or the like for a gas flow path is formed.
  • the fuel cell separator manufactured by the present invention is obtained by molding and curing graphite powder and thermosetting resin into a predetermined shape. As such or as necessary, groove processing, drilling, and the like are performed. It is used as a fuel cell separator. Further, the term “fuel cell separator” is understood to include a molded product for a fuel cell separator before processing.
  • the fuel cell separator composition of the present invention contains graphite powder and an epoxy resin binder as essential components. Further, it usually contains a curing accelerator.
  • the mixing ratio of the graphite powder and the epoxy resin binder is 2 to 10 parts by weight, preferably 3 to 7 parts by weight, per 1 part by weight of the epoxy resin binder. If the amount of graphite powder is large, the fluidity during molding is inferior and a large amount of pressure is required for molding, which increases the cost of the molding machine. On the other hand, if the amount of graphite powder is small, the electrical conductivity becomes insufficient.
  • the graphite powder used in the present invention is not limited as long as it exhibits high conductivity.
  • carbonaceous materials such as mesocarbon microbeads are graphitized, and coal-based coats and petroleum-based coatas are manufactured by Kurofune.
  • natural graphite At least one of quiche graphite and expanded graphite is used.
  • one or more of coal-based and Z- or petroleum-based heavy oils are used as raw materials, and are treated at 600 ° C or lower to produce raw coats, and the raw coats are processed.
  • the ground raw material is carbonized at 700 to 1500 ° C and then graphited at 2000 ° C or higher.
  • the raw coat is formed by heat treatment, particularly by using a delayed core. It is preferable that the average particle size of the crushed raw coat is 1-150 m.
  • the pulverized raw coats are pulverized (pulverization in the present invention means turning large particles or agglomerates into powder having a smaller particle diameter. It is preferable to adjust the average particle size to 3-50 / zm.
  • any one of the treatment steps prior to the graphitizing treatment that is, 0.05 to 40% by weight of a graphitization catalyst is added to the heavy oil, the ground raw coals or the carbonized carbonized material. It is preferable to calories.
  • the graphitization catalyst is preferably at least one selected from boron, silicon, iron and compounds thereof.
  • the obtained graphite powder preferably has a BET specific surface area of 10 m 2 Zg or less.
  • heavy coal-based oil (coal tar-based raw material) is obtained from coal tar produced by carbonization of coal, high-boiling tar oil separated from coal tar, tar pitch, and the like. ) Is desirable.
  • it is tar pitch.
  • Talbitsch has a soft pitch with a softening point of 70 ° C or less, a medium pitch with a softening point of about 70-85 ° C, and a high pitch with a softening point of 85 ° C or more. It is advantageous to use a soft pitch for Also, a mixture of two or three types of tar pitch, coal tar or high boiling tar oil may be used.
  • Examples of the petroleum heavy oil include catalytic cracking oil, atmospheric residual oil, and vacuum residual oil.
  • decant oil FCC-DO
  • these heavy oils may be removed by distillation of light components in advance, or may be subjected to heat treatment and heavy polymerization by heat polymerization, in terms of the carbonization yield.
  • Heavy petroleum heavy oils contain almost no QI.
  • the heavy coal oil and the heavy petroleum oil may be used, for example, at a mixing ratio of 10 to 80 wt% of the heavy petroleum oil to the heavy coal oil.
  • the raw coatas refers to semi-solid coatas having a volatile content (weight loss when heated at 950 ° C for 7 minutes) of 3% or more, preferably 5% or more.
  • the production of raw coats with delayed coke is carried out at a coking temperature of 600 ° C or less, usually 400 ° C-600 ° C, preferably 450-500 ° C.
  • the processing temperature may be determined.
  • Raw coats produced in Delayco are cut out using jet water, then the water content is adjusted and crushed.
  • the pulverization is carried out by first using a coarse pulverizer such as a jaw crusher, and then using a fine pulverizer such as a hammer crusher to obtain an average particle diameter of 1 to 50 ⁇ m, preferably 15 to 35 ⁇ m. If the average particle size exceeds 50 m, the thickness of the fuel cell separator as a graphite molded article may be larger than the thinnest part, so that the specific surface area of the obtained graphite material is increased, and the physical properties of the separator are reduced. This leads to a decrease in bulk density, an increase in specific resistance, a decrease in bending strength, and an increase in gas permeability. On the other hand, it is very difficult to grind to an average particle size of less than 1 m, and the surface area increases, so the amount of resin must be increased, which leads to an increase in intrinsic resistance.
  • a coarse pulverizer such as a jaw crusher
  • a fine pulverizer such as a hammer crusher
  • the pulverizer used here is not particularly limited, and any type of pulverizer may be used as long as it has a target average particle diameter.
  • the raw coat is carbonized.
  • the carbonization temperature is preferably 700 ° C to 1500 ° C, more preferably 800 ° C to 1200 ° C.
  • the carbonization treatment may be performed using a lead-nomer-type carbonization furnace that effectively uses waste heat by placing raw coals in a container, or a burner-type batch-type carbonization furnace.
  • the type of furnace is not particularly limited. At a temperature at which volatiles are scattered, it is preferable that the heating rate be as low as about 10 ° C / hr, since the carbonization yield increases, but this is not particularly limited.
  • the graphitization catalyst is preferably one that forms carbide with carbon or one that dissolves in carbon.
  • boron compounds, iron compounds, silicon compounds and their metals are desirable. When these compounds and metals are solid, they can be pulverized and then mixed with the raw materials, or those which are soluble in a solvent, for example, alcohols, can be mixed with the raw materials and used.
  • the compounding ratio of the graphitization catalyst is preferably in the range of 0.05 to 40 wt%.
  • the physical properties of the fuel cell separator can be improved, that is, the bulk density, the specific resistance, the bending strength, and the gas permeability can be reduced.
  • the graphitizing catalyst described above is blended with the carbide heat-treated at 700-1500 ° C. It is good.
  • the compounding ratio of the graphitization catalyst is in the range of 0.05 to 40 wt% with respect to the carbide.
  • the graphite temperature is preferably 2000 ° C or more, more preferably 2500 ° C or more.
  • the average particle diameter of the graphite-treated material is adjusted to 3 to 50 m, and the specific surface area is preferably 10 m 2 / g or less so that the amount used when kneading with the resin is minimized. 5m 2 / g or less is more desirable.
  • the force should be in the range of 1-3.1.6!
  • the raw material obtained by pulverizing the raw coat containing volatiles, firing and graphitizing the material contains volatiles! It has a rounder shape than the graphite-rided product, and greatly contributes to the improvement of the molding yield (cracking or cracking at the time of molding, visual inspection after molding) as a fuel cell separator, and improvement of physical properties. It is considered that
  • the graphite powder used in the present invention may have a single particle size of 3 to 50 m in average particle size to facilitate the pulverization or pulverization of the obtained compound, or a secondary pulverization of graphite particles. If it is desired to further reduce the specific resistance due to the effect, graphite powder having two types of particle size distribution may be used together. That is, a large particle size graphite powder having an average particle size of 50-300 m, preferably 70-150 m, and a small particle size having an average particle size of less than 50 m, preferably 5-20 m. It may be a mixture of graphite powder! / ⁇ .
  • the ratio between the large particle size graphite powder and the small particle size graphite powder is 40: 60-90: 10 by weight.
  • two types of graphite powders large particles are ground during the milling after kneading and a new coat surface emerges, so that a conductive path can be made in contact, while large particles have a small surface area It is expected that kneading is possible even with a small amount of resin. For small particles, it is expected that the strength of molded products will be improved while the contact between graphite particles is improved. It is also effective for increasing the bulk density. Further, if desired, a mixture of isotropic graphite powder and anisotropic graphite powder, for example, a mixture of 40:60 to 90:10 may be used.
  • the epoxy resin binder used in the present invention binds and solidifies graphite powder with a predetermined strength, and also has an epoxy resin and epoxy resin curing agent power. If desired, a curing accelerator can be added to the composition of the present invention or the epoxy resin binder, but it is not calculated as an epoxy resin binder!
  • the epoxy resin blended in the epoxy resin binder of the present invention has a viscosity at 150 ° C. of 120 mPa's, a melting point of 45 ° C. to 130 ° C., preferably 50 ° C. to 130 ° C., at room temperature. It is desirable to use one or more solid low-viscosity crystalline epoxy resins. As a result, at room temperature, the composition or compound is excellent in storage stability, and at the temperature at the time of molding, it shows good fluidity even when a relatively large amount of graphite powder is contained. it can.
  • the epoxy equivalent should be about 150-300 g / eq, preferably 170-250 g / eq.
  • Such a low-viscosity crystalline epoxy resin may be an ether-type or thioether-type epoxy resin represented by the above general formula (1), wherein X is O or S.
  • G is a glycidyl group
  • R is a monovalent group, which is a halogen atom or a hydrocarbon group having 16 carbon atoms which may be the same or different.
  • it is an alkyl group having 13 to 13 carbon atoms, and the number n of the substituents other than the hydrogen atom in one benzene ring is 0 to 4 !.
  • the epoxy resin often contains an oligomer by polymerization of the epoxy resin represented by the general formula (1).
  • the low-viscosity crystalline epoxy resin which is solid at room temperature is contained in the epoxy resin in an amount of 30% by weight or more, preferably 50% by weight or more, and more preferably 80% by weight or more. If another epoxy resin that is not a strong crystalline epoxy resin is used as at least a part of the epoxy resin component, a low-viscosity epoxy resin is preferred, for example, bisphenol F type epoxy resin, Biphenyl type epoxy resin and the like can be mentioned.
  • the curing agent for the epoxy resin may be a known one such as a phenol-based, amine-based, or carboxylic acid-based resin.
  • the curing agent is a polyvalent phenol, and more preferably, a phenol-alkyl phenol. It is a novolak curing agent obtained from formalin. It is advantageous that the novolac curing agent has a softening point at room temperature or higher.
  • the equivalent ratio between the epoxy resin and the curing agent is not particularly limited, but is preferably in the range of 0.5 to 1.5.
  • an epoxy resin curing accelerator When an epoxy resin curing accelerator is blended, known accelerators such as amines, imidazoles, ureas, organic phosphines, and Lewis acids can be used as the curing accelerator.
  • the amount of the curing accelerator is not particularly limited, but is preferably in the range of 0.01 to 10 parts by weight based on 100 parts by weight of the epoxy resin binder.
  • a dimethyl pereas type accelerator is mentioned as a preferable hardening accelerator.
  • the epoxy resin binder comprises an epoxy resin and a curing agent, and advantageously has an epoxy resin viscosity at 150 ° C of 120 mPa's, preferably 15 mPa's or less, more preferably 15 mPa's or less.
  • Epoxy resin containing 1 or more types of crystalline epoxy resin which is 1 OmPa's or less and is solid at room temperature (25 ° C).
  • the crystalline epoxy resin has a melting point of 45 to 130 ° C, preferably 50 to 130 ° C.
  • the epoxy resin may be composed of only the above-mentioned crystalline epoxy resin or may be a mixture with other epoxy resins. Alternatively, the epoxy resin as a whole may have the above viscosity and softness.
  • the epoxy resin binder also has a viscosity at 150 ° C of 500 mPa's or less and a softening point or a melting point of 45 to 130 ° C. As a result, not only is the storage stability excellent, but also good fluidity can be exhibited during molding. It is easy to adjust the viscosity to such a value by selecting the softening point and the viscosity of the epoxy resin and the curing agent.
  • the fuel cell separator composition of the present invention also includes an internal release agent such as stearic acid and wax, and other conductive fillers.
  • an internal release agent such as stearic acid and wax, and other conductive fillers.
  • the graphite powder and the resin binder may be mixed at the same time.
  • the graphite powder having at least two types of particle size distribution may be mixed in advance, and then mixed with the resin binder. ⁇ .
  • a resin component consisting of graphite powder, an epoxy resin binder, a curing accelerator, and additives to be blended as necessary. After heating and kneading, the mixture is pulverized or crushed so that the average particle size is 100 m or less, preferably 20 to 50 m. . C-1 350. C, preferably 140. C-1 230. C, more preferably 150. C-200. It is advantageous to mold and cure in C.
  • kneading is performed using a kneader.
  • a kneader a general-purpose kneader, roll, single-screw extruder, multi-screw extruder, or the like can be used, but is not limited thereto.
  • the kneading is performed so that the resin and the graphite powder form a composition as uniform as possible.
  • heating may be performed to reduce the viscosity of the resin, or a low-boiling solvent may be added, but it is necessary that curing is not completed.
  • the composition obtained by kneading is pulverized or crushed.
  • the pulverization can be performed using a known pulverizer.
  • the pulverizer used here include a pulverizer for shear pulverization and a disk mill for compression pulverization.
  • graphite powders with different average particle sizes are used in this pulverization process, the graphite powder with a large particle size is preferentially pulverized, resulting in the adhesion of grease and the generation of a new graphite fracture surface. This has the effect of lowering the resistance.
  • the graphite powder with an average particle size of 50-300 m used as a raw material is selectively pulverized to 50 m or less, and the graphite powder with an average particle size of less than 50 m is pulverized as much as possible. It is advantageous not to do so. If the pulverization is more than necessary, the resin may not be sufficiently distributed and the strength of the molded article may be reduced.
  • the viscosity at 150 ° C of the compound (crushed product) obtained by grinding as described above is 200 to 3000 Pa's, preferably ⁇ 2000 Pa's or less, more preferably ⁇ 1500 Pa's or less. Or 200-1200Pa ⁇ s!
  • the viscosity at 150 ° C of such a compound is determined by the type of graphite and epoxy resin binder used, the presence or absence of a curing accelerator, the force that varies depending on the kneading temperature and time, etc. It is preferable that the value obtained by measuring the compound obtained under the conditions shown in the examples indicates the above viscosity. This viscosity is determined mainly by selecting the amounts of the epoxy resin and graphite. Although the viscosity of the compound increases when left for a long period of time, the viscosity may be indicated immediately before the compound is used for manufacturing a fuel cell separator.
  • a small amount of components such as graphite powder, an epoxy resin binder, and a curing accelerator added as needed (hereinafter, components other than the graphite material are mainly resin, and are also referred to as resin components, etc.)
  • the composition of the present invention comprises a graphite material and a resin component, and the resin component may contain a small amount of components other than the resin.
  • the composition of the present invention is kneaded, and the kneaded product is pulverized to 100 ⁇ m or less, preferably 3 to 50 ⁇ m, and more preferably 20 to 50 ⁇ m, and then molded to form a fuel cell separator. Is obtained.
  • the pulverized material Since the pulverized material is kneaded at a temperature of about 100 ° C, it is a partially incompletely cured product in which curing is progressing, and is pressed and molded at a temperature of about 140 ° C or more. When held for a predetermined time, it becomes a cured product (molded article or separator).
  • This compound should have a viscosity of 200-3000Pa's at 150 ° C! / ⁇ .
  • the method of forming the separator depends on the mixing ratio of graphite and the resin binder, but press molding, transfer molding, and injection molding using a mold in which holes and grooves in the separator are processed can be used.
  • press molding transfer molding and injection molding are preferred when the amount of resin added is low and when the amount of resin added is relatively large and the compound has fluidity.
  • thermoplastic resin is used, continuous forming using a design roll having a grooved hole is also applicable.
  • the temperature is set to 100 to 350 ° C, preferably 140 to 230 ° C, more preferably about 150 to 200 ° C. It is better to hold it.
  • the temperature should be higher than the curing temperature of the thermosetting resin to be used and lower than the carbonization temperature.
  • the molding pressure is preferably higher to reduce the electrical resistivity in the surface direction and increase the bulk density. Bur, since the equipment cost to increase the pressure increases, 20- lOOOkg / cm 2 or so, preferably 100- 800 kg / cm 2, more preferably suitably about 100- 500kg / cm 2.
  • a separator with a thickness of 2 mm and an area of about 700 cm 2 can be molded within a molding time of less than 20 minutes, especially less than 5 minutes, and a dimensional accuracy of less than 100 / zm, especially less than 50 m.
  • the fuel cell separator can be used as it is or with a simple casing. However, after being formed into a plate or the like, a fuel cell separator is prepared by adding a groove and a hole to the plate to form a fuel cell separator.
  • the fuel cell separator obtained by the production method of the present invention can have a bulk density of 1.80 g / cm 3 or more, preferably 1.85 g / cm 3 or more, and is gas-impermeable and mechanical.
  • the target strength is also excellent.
  • the bulk density is less than 1.80 g / cm 3 , not only gas impermeability is inferior but also mechanical strength is inferior.
  • the specific resistance is required to be 100 m ⁇ cm or less, preferably 40 mQcm or less in order to function as a fuel cell, the required characteristics can be sufficiently achieved.
  • This specific resistance can be lowered by increasing the type of graphite to be used with a high degree of crystallinity or by reducing the amount of the thermosetting resin, and can also be changed by molding pressure and the like.
  • the specific resistance is determined according to the measuring method described in the examples described later.
  • the fuel cell separator of the present invention has a bending strength of 30 MPa or more and a gas permeability of 1
  • the separator may oxygen and hydrogen as fuel if the vibration or shock can become corrupted resistance high instrument gas permeability greater than 1 X 10- 14 cm 2 is mixed power generation Impairs efficiency.
  • the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto.
  • the methods for measuring the specific resistance, compound viscosity, and dimensional accuracy of the molded body are as follows.
  • Compound viscosity High-low type flow tester (Shimadzu Flote, manufactured by Shimadzu Corporation) Star CFT-500).
  • the actual nozzle size used in the measurement was ⁇ 1 ⁇ L1.
  • about 2 g of the sample (crushed material) was first compression-molded into a tablet with a size of approximately ⁇ 10 ⁇ L7 at room temperature.
  • the viscosity measuring device which has been heated to the measurement temperature (150 ° C) in advance, hold it for 10 sec, measure the viscosity at a shear rate of 5000 1 / s.
  • Thickness accuracy The thickness of a predetermined portion of a molded body obtained under predetermined molding conditions was measured, and the maximum value-minimum value was defined as the thickness accuracy. In the evaluation of thickness accuracy, ⁇ : less than 50 / ⁇ , ⁇ : less than 50-100 ⁇ m, X: 100 m or more.
  • the molded product was measured by a four-terminal voltage drop method.
  • the specific resistance is measured in the thickness direction (press forming pressure direction) and in the plane direction (perpendicular to the press forming pressure direction).
  • the specific resistance shown in this example is particularly important as a separator characteristic. The values in the thickness direction are shown.
  • the raw materials used are as follows.
  • Highly conductive graphite Lumpy raw coats produced by delayed coking using heavy coal-based oil were pulverized with a Raymond mill to an average particle size of 30 m. This was carbonized at about 800 ° C in a lead normal furnace to obtain carbide. Kurosuzuri was performed at 2800 ° C. with 5% boron carbide added to this carbide.
  • Ether type epoxy resin manufactured by Toto Kasei Co., Ltd., trade name YSLV-80DE, melting point 79 ° C, viscosity at 150 ° C 0.006 Pa's
  • Thioether type epoxy resin manufactured by Toto Kasei Co., Ltd., trade name YSLV-50TE, melting point 50. C, 150 ° C viscosity 0.006Pa's
  • Tetramethylbisphenol F-type epoxy resin manufactured by Nippon Steel Chemical Co., Ltd., trade name YSLV-80XY, melting point 78, viscosity at 150 ° C 0.008 Pa's
  • Phenol novolak resin Tamanol 758 manufactured by Arakawa Chemical Co., Ltd., softening point 83 ° C, 150 ° C viscosity 0.22-0.35Pa's
  • Curing accelerator dimethyl urea-based accelerator Sanapro Co., Ltd., trade name U-CAT3502T
  • Table 1 shows the measurement results of the viscosity (compound viscosity) of the powder frame, the dimensional accuracy of the compact, and the specific resistance.
  • a pulverized product and a molded product were manufactured in the same manner as in Example 1 with the composition shown in Table 1, and the physical properties were measured. The results are shown in Table 1.
  • a pulverized product and a molded product were manufactured in the same manner as in Example 1 with the composition shown in Table 1, and the physical properties were measured. The results are shown in Table 1.
  • EOCN-1020 100 100 100 Tamanol 758 65 65 65 65 63 55 54 54 54 Hardening accelerator 1.6 1.6 1.61-6 1.6 1.6 1.6 1.6 1.6 1.6 Graphite 495 660 825 1155 652 620 462 616 770 Graphite / resin ratio 3 4 5 7 4 4 3 4 5
  • the material which required characteristics as a fuel cell separator ie, electrical conductivity, mechanical strength, etc.
  • the moldability can be further improved.
  • it can provide a compound material that can shorten the molding cycle, has excellent dimensional accuracy, and can be used in mass production of separators in the future, and makes an extremely large contribution in this field.
  • the fuel cell sensor router obtained by the production method of the present invention is dense, has high mechanical strength, has excellent conductivity, has low anisotropy, and has a low gas permeability. A highly efficient, long-life fuel cell can be achieved.

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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

L'invention concerne un matériau à composé de graphite/résine répondant aux exigences de performances d'un séparateur de pile à combustible et possédant en même temps une excellente aptitude au moulage, de manière à raccourcir le cycle de moulage, et une excellente précision dimensionnelle, aux fins de production en série de séparateurs. L'invention concerne une composition destinée à un séparateur de pile à combustible comprenant de la poudre de graphite et un liant de résine éopxyde renfermant une résine époxyde et un agent de durcissement, la composition étant produite par mélange d'un liant de résine époxyde avec de la poudre de graphite représentant entre 3 à 7 fois le poids du liant de résine époxyde, puis pas malaxage et pulvérisation du mélange, de manière à obtenir un composé dont la viscosité à 150°C est comprise dans la gamme allant de 200 à 3000 Pa·s et dont la résistance électrique spécifique sous la forme d'un moulage de séparateur de pile à combustible est égale ou inférieure à 40 mΩcm en termes de résistivité. Une résine époxyde cristalline possédant une viscosité à 150°C comprise entre 1 et 20 mPa·s et un point de fusion compris entre 45 et 130°C et étant solide à des températures ordinaires est conçue pour la résine époxyde susmentionnée.
PCT/JP2004/019031 2003-12-26 2004-12-20 Composition destinee a un separateur de pile a combustible et procede de production de celui-ci WO2005064721A1 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108780903A (zh) * 2016-03-15 2018-11-09 日清纺化学株式会社 燃料电池用多孔隔板

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000239488A (ja) * 1999-02-19 2000-09-05 Nichias Corp 樹脂組成物
JP2002075394A (ja) * 2000-09-04 2002-03-15 Nippon Steel Chem Co Ltd 燃料電池用セパレータ部材
JP2002083609A (ja) * 2000-09-07 2002-03-22 Nippon Steel Chem Co Ltd 燃料電池用セパレータ用組成物及びその製造方法
JP2002083608A (ja) * 2000-09-07 2002-03-22 Nippon Steel Chem Co Ltd 燃料電池用セパレータ及びその製造方法
JP2002164063A (ja) * 2000-09-13 2002-06-07 Mitsui Takeda Chemicals Inc 固体高分子型燃料電池用セパレーターおよびその製造方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000239488A (ja) * 1999-02-19 2000-09-05 Nichias Corp 樹脂組成物
JP2002075394A (ja) * 2000-09-04 2002-03-15 Nippon Steel Chem Co Ltd 燃料電池用セパレータ部材
JP2002083609A (ja) * 2000-09-07 2002-03-22 Nippon Steel Chem Co Ltd 燃料電池用セパレータ用組成物及びその製造方法
JP2002083608A (ja) * 2000-09-07 2002-03-22 Nippon Steel Chem Co Ltd 燃料電池用セパレータ及びその製造方法
JP2002164063A (ja) * 2000-09-13 2002-06-07 Mitsui Takeda Chemicals Inc 固体高分子型燃料電池用セパレーターおよびその製造方法

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108780903A (zh) * 2016-03-15 2018-11-09 日清纺化学株式会社 燃料电池用多孔隔板
EP3432396A4 (fr) * 2016-03-15 2019-08-28 Nisshinbo Chemical Inc. Séparateur poreux pour piles à combustible
CN108780903B (zh) * 2016-03-15 2022-02-01 日清纺化学株式会社 燃料电池用多孔隔板

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