JP2006004853A - Separator for solid polymer fuel cell and its manufacturing method - Google Patents

Separator for solid polymer fuel cell and its manufacturing method Download PDF

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JP2006004853A
JP2006004853A JP2004182251A JP2004182251A JP2006004853A JP 2006004853 A JP2006004853 A JP 2006004853A JP 2004182251 A JP2004182251 A JP 2004182251A JP 2004182251 A JP2004182251 A JP 2004182251A JP 2006004853 A JP2006004853 A JP 2006004853A
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separator
fuel cell
polymer electrolyte
metal
electrolyte fuel
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Haruo Iwano
治雄 岩野
Munenori Iizuka
宗紀 飯塚
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Bridgestone Corp
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    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30Hydrogen technology
    • Y02E60/50Fuel cells
    • YGENERAL 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
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    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00Climate change mitigation technologies in the production process for final industrial or consumer products
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a separator for a solid polymer fuel cell, of low cost, low volume resistance and low contact resistance, excellent in corrosion resistance, capable of being recycled, and usable for a long period of time, as well as a manufacturing method of the separator. <P>SOLUTION: The separator for the solid polymer fuel cell is formed by pressing a mixture consisting of metal powder 2, thermoplastic resin 3 as a binder, and graphite powder 4, and the separator for the solid polymer fuel cell is manufactured by filling the mixture consisting of the metal powder 2, the thermoplastic resin 3 as the binder, and the graphite powder in a die having a groove shape, and applying a passive film 5 forming treatment by heating the mixture with pressure and baking it. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、固体高分子型燃料電池用セパレータ及び該固体高分子型燃料電池用セパレータの製造方法に関し、特に安価で、体積抵抗及び接触抵抗が低く、耐食性に優れ、更には、リサイクルが可能で、長期に渡って使用可能な固体高分子型燃料電池用セパレータに関するものである。   The present invention relates to a polymer electrolyte fuel cell separator and a method for producing the polymer electrolyte fuel cell separator, and is particularly inexpensive, has low volume resistance and contact resistance, excellent corrosion resistance, and can be recycled. The present invention relates to a polymer electrolyte fuel cell separator that can be used for a long time.

近年、発電効率の優れた電池として、固体高分子型燃料電池が注目を集めている。該固体高分子型燃料電池は、アノード用セパレータに、アノード電極、触媒、固体高分子膜、触媒、カソード電極、カソード用セパレータを順次積層して構成されおり、水素又はメタノール等の燃料と酸素とを用いて発電が可能である。ここで、セパレータは、燃料と酸素とを別々にアノード極側とカソード極側に供給する流路として機能すると共に、燃料の酸化反応によって生じる電子を伝える通電体としての機能も有する。そのため、セパレータの導電性は、燃料電池の性能に大きく影響する。   In recent years, solid polymer fuel cells have attracted attention as batteries with excellent power generation efficiency. The polymer electrolyte fuel cell is configured by sequentially laminating an anode electrode, a catalyst, a solid polymer membrane, a catalyst, a cathode electrode, and a cathode separator on an anode separator, and a fuel such as hydrogen or methanol and oxygen It is possible to generate electricity using Here, the separator functions as a flow path for separately supplying fuel and oxygen to the anode electrode side and the cathode electrode side, and also has a function as an electric conductor that transmits electrons generated by the oxidation reaction of the fuel. Therefore, the conductivity of the separator greatly affects the performance of the fuel cell.

従来、上記アノード用セパレータ及びカソード用セパレータとしては、熱硬化性樹脂をバインダーとした黒鉛製セパレータが主に用いられている。しかしながら、該熱硬化性樹脂を用いた黒鉛製セパレータにおいては、精密な機械加工が必要なためコストが高く、また、該黒鉛製セパレータは、リサイクル性に乏しいという欠点を有している(特許文献1参照)。また、加熱成形中に熱硬化性樹脂から水が発生し、該水に起因してセパレータ中に気泡が形成され、セパレータのガス遮蔽性が低下するという問題があり、この問題に対しては、例えば、金型に金属板を配置し、該金属板の両側にカーボン粉をフェノール樹脂で被覆した焼成材料を充填し、該焼成材料を大気中で加熱焼成してセパレータを形成することで、セパレータのガス遮断性を改善できることが知られているが(特許文献2参照)、コスト及びリサイクル性に関しては、依然として改善の余地がある。   Conventionally, as the anode separator and the cathode separator, a graphite separator using a thermosetting resin as a binder is mainly used. However, the graphite separator using the thermosetting resin is expensive because it requires precise machining, and the graphite separator has a disadvantage of poor recyclability (Patent Literature). 1). In addition, water is generated from the thermosetting resin during thermoforming, bubbles are formed in the separator due to the water, and there is a problem that the gas shielding property of the separator is lowered. For example, by placing a metal plate in a mold, filling a fired material in which carbon powder is coated with a phenol resin on both sides of the metal plate, and firing the fired material in the air to form a separator, the separator Although it is known that the gas barrier property of the gas can be improved (see Patent Document 2), there is still room for improvement in terms of cost and recyclability.

また、上記黒鉛製セパレータの他にも、チタンやステンレス製の金属製セパレータが知られている。しかしながら、燃料電池のセパレータの使用環境は、非常に酸性が強いため、金属製セパレータにおいては、金属の表面に耐食性の高い金属をメッキする等して耐食性を向上させる必要があり、コストが上昇してしまうという問題がある。また、燃料電池は複数のセルを積層して使用されることが多く、軽量化の要請が強いのに対し、金属製セパレータを使用すると燃料電池の重量増加が大きいため、金属製セパレータの使用は重量の点でも問題がある。   In addition to the above graphite separators, titanium and stainless steel metal separators are known. However, the usage environment of fuel cell separators is very acidic, so in metal separators, it is necessary to improve the corrosion resistance by, for example, plating a metal with high corrosion resistance on the surface of the metal, which increases costs. There is a problem that it ends up. In addition, a fuel cell is often used by stacking a plurality of cells, and there is a strong demand for weight reduction. However, when a metal separator is used, the weight of the fuel cell increases greatly. There is also a problem in terms of weight.

更に、金属製セパレータにおいては、金属の表面に不動態膜を生成させて、金属セパレータの耐食性を向上させることもあるが、この場合、セパレータの体積抵抗及び接触抵抗が上昇してしまい、燃料電池の電池性能が悪化するという問題があった。   Furthermore, in a metal separator, a passive film may be formed on the surface of the metal to improve the corrosion resistance of the metal separator, but in this case, the volume resistance and contact resistance of the separator are increased, and the fuel cell There was a problem that the battery performance deteriorated.

これに対し、フェライト系ステンレス鋼基材にカーボン粉末を分散付着させてなる燃料電池用セパレータが提案されている(特許文献3参照)。該セパレータにおいては、カーボン粒子と基材との間の抵抗が低減されており、セパレータの接触抵抗及び接触抵抗を低減することができるものの、セパレータ表面が摩耗した場合に、ステンレス鋼基材が露出し、ステンレス鋼が露出した部分に不動態膜が形成され、セパレータの体積抵抗及び接触抵抗が上昇してしまうという問題があった。   On the other hand, a fuel cell separator in which carbon powder is dispersed and adhered to a ferritic stainless steel substrate has been proposed (see Patent Document 3). In the separator, the resistance between the carbon particles and the substrate is reduced, and the contact resistance and contact resistance of the separator can be reduced, but the stainless steel substrate is exposed when the separator surface is worn. However, there is a problem that a passive film is formed on the exposed portion of the stainless steel, and the volume resistance and contact resistance of the separator are increased.

国際公開第01/085849号パンフレットInternational Publication No. 01/0885849 Pamphlet 特開2003−217609号公報JP 2003-217609 A 特開2000−277133号公報JP 2000-277133 A

そこで、本発明の目的は、上記従来技術の問題を解決し、安価で、体積抵抗及び接触抵抗が低く、耐食性に優れ、更には、リサイクルが可能で、長期に渡って使用可能な固体高分子型燃料電池用セパレータを提供することにある。また、本発明の他の目的は、かかる固体高分子型燃料電池用セパレータの製造方法を提供することにある。   Therefore, the object of the present invention is to solve the above-mentioned problems of the prior art, inexpensive, low in volume resistance and contact resistance, excellent in corrosion resistance, recyclable, and usable for a long period of time. It is providing the separator for type fuel cells. Another object of the present invention is to provide a method for producing such a polymer electrolyte fuel cell separator.

本発明者らは、上記目的を達成するために鋭意検討した結果、金属粉と、熱可塑性樹脂と、黒鉛粉とからなる混合物をプレスして固体高分子型燃料電池用セパレータを成形することで、安価で且つリサイクルが可能で、体積抵抗及び接触抵抗が低く、耐食性に優れた固体高分子型燃料電池用セパレータが得られ、該セパレータは、セパレータ内部まで黒鉛粉が均一に混入されているため、表面が摩耗しても体積抵抗及び接触抵抗の変化が小さく、長期に渡って使用可能であることを見出し、本発明を完成させるに至った。   As a result of diligent studies to achieve the above object, the present inventors have pressed a mixture of metal powder, thermoplastic resin, and graphite powder to form a polymer electrolyte fuel cell separator. A solid polymer fuel cell separator that is inexpensive and recyclable, has low volume resistance and low contact resistance, and has excellent corrosion resistance is obtained because graphite powder is uniformly mixed into the separator. The inventors have found that even when the surface is worn, the changes in volume resistance and contact resistance are small and can be used for a long time, and the present invention has been completed.

即ち、本発明の固体高分子型燃料電池用セパレータは、金属粉と、バインダーとしての熱可塑性樹脂と、黒鉛粉とからなる混合物をプレスしてなることを特徴とする。   That is, the polymer electrolyte fuel cell separator of the present invention is characterized by being formed by pressing a mixture of metal powder, a thermoplastic resin as a binder, and graphite powder.

本発明の固体高分子型燃料電池用セパレータの好適例においては、前記金属粉が、不動態膜を生成することが可能な金属からなる。ここで、該不動態膜を生成することが可能な金属としては、アルミニウム、ステンレス及びチタンが好ましい。   In a preferred example of the polymer electrolyte fuel cell separator of the present invention, the metal powder is made of a metal capable of generating a passive film. Here, aluminum, stainless steel, and titanium are preferable as the metal capable of generating the passive film.

本発明の固体高分子型燃料電池用セパレータの他の好適例においては、前記金属粉の含有率が20〜40体積%である。この場合、セパレータの導電性及び機械的強度を十分に確保することができる。   In another preferred embodiment of the polymer electrolyte fuel cell separator of the present invention, the content of the metal powder is 20 to 40% by volume. In this case, the conductivity and mechanical strength of the separator can be sufficiently ensured.

本発明の固体高分子型燃料電池用セパレータの他の好適例においては、前記熱可塑性樹脂の含有率が20〜30体積%である。   In another preferable example of the solid polymer fuel cell separator of the present invention, the content of the thermoplastic resin is 20 to 30% by volume.

本発明の固体高分子型燃料電池用セパレータの他の好適例においては、前記黒鉛粉の含有率が40〜60体積%である。この場合、セパレータの接触抵抗を十分に低下させつつ、セパレータの機械的強度を十分に確保することができる。   In another preferred embodiment of the polymer electrolyte fuel cell separator of the present invention, the content of the graphite powder is 40 to 60% by volume. In this case, it is possible to sufficiently ensure the mechanical strength of the separator while sufficiently reducing the contact resistance of the separator.

また、本発明の固体高分子型燃料電池用セパレータの製造方法は、金属粉と、バインダーとしての熱可塑性樹脂と、黒鉛粉とからなる混合物を溝形状を有する金型に充填し、該混合物を加熱加圧焼成して、金属粉に不動態膜生成処理を施しつつ成形することを特徴とする。   The method for producing a separator for a polymer electrolyte fuel cell according to the present invention comprises filling a metal mold, a thermoplastic resin as a binder, and a graphite powder into a mold having a groove shape, and using the mixture. It is characterized in that it is molded while being heated and pressed and subjected to a passive film generation treatment on the metal powder.

本発明によれば、金属粉と、熱可塑性樹脂と、黒鉛粉とからなる混合物をプレスしてなり、安価で、体積抵抗及び接触抵抗が低く、耐食性に優れ、リサイクルが可能で、長期に渡って使用可能な固体高分子型燃料電池用セパレータを提供することができる。また、かかる固体高分子型燃料電池用セパレータの製造方法を提供することができる。   According to the present invention, a mixture of metal powder, thermoplastic resin, and graphite powder is pressed, is inexpensive, has low volume resistance and contact resistance, is excellent in corrosion resistance, is recyclable, and can be recycled over a long period of time. It is possible to provide a separator for a polymer electrolyte fuel cell that can be used. Moreover, the manufacturing method of this separator for polymer electrolyte fuel cells can be provided.

以下に、本発明の固体高分子型燃料電池用セパレータを図を参照しながら詳細に説明する。図1は、本発明の固体高分子型燃料電池用セパレータの一例の断面図を示す。図示例の固体高分子型燃料電池用セパレータ1は、金属粉2と、バインダーとしての熱可塑性樹脂3と、黒鉛粉4とからなる混合物をプレスしてなる導電性成形体であり、該成形体の外表面部に位置する金属粉2には不動態膜5が形成されている。なお、通常、セパレータ1には、燃料及び酸素等を流すための流路が形成されているが、図1においては、簡略化のために流路を省略してある。   Hereinafter, the polymer electrolyte fuel cell separator of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a cross-sectional view of an example of a polymer electrolyte fuel cell separator of the present invention. The illustrated polymer electrolyte fuel cell separator 1 is a conductive molded body formed by pressing a mixture of a metal powder 2, a thermoplastic resin 3 as a binder, and a graphite powder 4. A passive film 5 is formed on the metal powder 2 located on the outer surface of the metal. Normally, the separator 1 is formed with a flow path for flowing fuel, oxygen, etc., but in FIG. 1, the flow path is omitted for the sake of simplicity.

本発明の固体高分子型燃料電池用セパレータ1の内部は、黒鉛粉4が均一に分散していると共に金属粉2に不動態膜5が生成していないため、導電性が良好で、体積抵抗が十分に低い。一方、セパレータ1の外表面部の金属粉2には不動態膜5が生成しているため、セパレータ1は、固体高分子型燃料電池の使用環境においても十分な耐食性を有しており、また、黒鉛粉4がセパレータ1の外表面部にも均一に分散しているため、表面に黒鉛粉4が一部露出しており、該露出部分の体積抵抗及び接触抵抗が低い。そのため、セパレータ1の外表面部も、導電性が良好で、電極等の隣接部材との接触抵抗が十分に抑制されている。また、本発明の固体高分子型燃料電池用セパレータ1は、安価且つ簡単に精度良く作製でき、精密な機械加工が不要なため、従来の黒鉛製セパレータよりも低コストであり、更に、黒鉛粉4及び熱可塑性樹脂3を含むため、従来の金属製セパレータよりも軽量であり、また更に、体積抵抗が金属製セパレータと同等程度に低く、耐食性が金属製セパレータよりも優れている。   In the solid polymer fuel cell separator 1 of the present invention, the graphite powder 4 is uniformly dispersed and the passive film 5 is not formed on the metal powder 2. Is low enough. On the other hand, since the passive film 5 is formed on the metal powder 2 on the outer surface of the separator 1, the separator 1 has sufficient corrosion resistance even in the use environment of the polymer electrolyte fuel cell. Since the graphite powder 4 is uniformly dispersed also on the outer surface portion of the separator 1, the graphite powder 4 is partially exposed on the surface, and the volume resistance and contact resistance of the exposed portion are low. Therefore, the outer surface portion of the separator 1 also has good conductivity, and contact resistance with adjacent members such as electrodes is sufficiently suppressed. Further, the solid polymer fuel cell separator 1 of the present invention can be produced inexpensively and easily with high accuracy and does not require precise machining, so that the cost is lower than that of a conventional graphite separator. 4 and the thermoplastic resin 3, it is lighter than conventional metal separators, and further has a volume resistance as low as that of metal separators, and has better corrosion resistance than metal separators.

加えて、本発明の固体高分子型燃料電池用セパレータ1においては、黒鉛粉4がセパレータ全体に均一に混入されているため、表面が摩耗したり、表面に傷が入った場合でも、順次内部に含まれる金属粉2及び黒鉛粉4が露出し、金属粉2については、セパレータの使用環境下で不動態膜5が形成されるため、初期と同様の表面が形成される。そのため、摩耗や傷によるセパレータの性能劣化を防止することができ、長期に渡って使用可能である。   In addition, in the polymer electrolyte fuel cell separator 1 of the present invention, the graphite powder 4 is uniformly mixed in the entire separator, so even if the surface is worn or scratched, The metal powder 2 and the graphite powder 4 contained in are exposed, and the metal powder 2 has the same surface as the initial stage because the passive film 5 is formed under the usage environment of the separator. Therefore, it is possible to prevent the performance of the separator from being deteriorated due to wear and scratches, and it can be used for a long time.

本発明の固体高分子型燃料電池用セパレータに用いる金属粉は、不動態膜を生成することが可能な金属からなるのが好ましく、該不動態膜を生成することが可能な金属としては、アルミニウム、ステンレス及びチタン等が好ましい。これら不動態膜を生成することが可能な金属からなる金属粉は、1種単独で用いてもよいし、2種以上を混合して用いてもよい。なお、本発明の固体高分子型燃料電池用セパレータにおいて、不動態膜は、主として金属酸化物からなる。   The metal powder used for the separator for a polymer electrolyte fuel cell of the present invention is preferably made of a metal capable of forming a passive film, and the metal capable of generating the passive film is aluminum. Stainless steel, titanium and the like are preferable. These metal powders made of a metal capable of forming a passive film may be used alone or in combination of two or more. In the separator for a polymer electrolyte fuel cell of the present invention, the passive film is mainly composed of a metal oxide.

本発明の固体高分子型燃料電池用セパレータにおける上記金属粉の含有率は、20〜40体積%の範囲が好ましい。セパレータ中の金属粉含有率が20体積%以上であれば、セパレータに十分な導電性を付与することができ、一方、40体積%を超えると、セパレータの機械的強度が低下したり、生成する不動態膜が厚くなるため、セパレータの導電性を十分に確保することが難しくなる。なお、本発明の固体高分子型燃料電池用セパレータの体積抵抗率は、7.0×10-3〜9.0×10-2Ω・cmの範囲が好ましい。 The content of the metal powder in the polymer electrolyte fuel cell separator of the present invention is preferably in the range of 20 to 40% by volume. If the metal powder content in the separator is 20% by volume or more, sufficient electrical conductivity can be imparted to the separator. On the other hand, if it exceeds 40% by volume, the mechanical strength of the separator is reduced or generated. Since the passive film is thick, it is difficult to sufficiently secure the conductivity of the separator. The volume resistivity of the solid polymer fuel cell separator of the present invention is preferably in the range of 7.0 × 10 −3 to 9.0 × 10 −2 Ω · cm.

上記金属粉の粒径は、10〜100μmの範囲が好ましい。金属粉の粒径が100μmを超えると、樹脂との混練が難しくなり、所望の体積含有率にならなくなってしまい、10μm未満では、黒鉛粉の粒径より小さくなるので、バインダーとしての樹脂が金属粉間の空隙に入り込めず、セパレータ表面に位置する黒鉛粉の脱落が多くなり、表面の面粗度が悪くなって、燃料電池とした時に接触抵抗が増大してしまう欠点がある。   The particle size of the metal powder is preferably in the range of 10-100 μm. When the particle size of the metal powder exceeds 100 μm, it becomes difficult to knead with the resin, and the desired volume content is not achieved. When the particle size is less than 10 μm, the particle size of the graphite powder is smaller, so the resin as the binder is a metal. There is a drawback that the graphite powder located on the separator surface is not able to enter the gap between the powders, the surface roughness is deteriorated, and the contact resistance is increased when the fuel cell is obtained.

本発明の固体高分子型燃料電池用セパレータにバインダーとして用いる熱可塑性樹脂としては、耐熱性、耐溶剤性、剛性、寸法安定性の観点から、ポリアミド、ポリアセタール及びポリブチレンテレフタレート等の汎用エンジニアリングプラスチック、並びにポリフェニレンサルファイド、ポリアミドイミド及びポリエーテルイミド等の特殊エンジニアリングプラスチックを好適に用いることができる。これら熱可塑性樹脂は、1種単独で用いてもよいし、2種以上を混合して用いてもよい。本発明の固体高分子型燃料電池用セパレータは、バインダーとして熱可塑性樹脂を用いているため、リサイクルが可能である。   As a thermoplastic resin used as a binder for the solid polymer fuel cell separator of the present invention, general-purpose engineering plastics such as polyamide, polyacetal, and polybutylene terephthalate from the viewpoint of heat resistance, solvent resistance, rigidity, and dimensional stability, In addition, special engineering plastics such as polyphenylene sulfide, polyamideimide, and polyetherimide can be preferably used. These thermoplastic resins may be used individually by 1 type, and 2 or more types may be mixed and used for them. Since the separator for a polymer electrolyte fuel cell of the present invention uses a thermoplastic resin as a binder, it can be recycled.

本発明の固体高分子型燃料電池用セパレータにおける上記熱可塑性樹脂の含有率は、20〜30体積%の範囲が好ましい。セパレータ中の熱可塑性樹脂含有率が20体積%以上であれば、セパレータの機械的強度を十分に確保することができ、30体積%以下とすることで、セパレータの導電性を十分に確保することができる。   The thermoplastic resin content in the polymer electrolyte fuel cell separator of the present invention is preferably in the range of 20 to 30% by volume. If the content of the thermoplastic resin in the separator is 20% by volume or more, the mechanical strength of the separator can be sufficiently secured, and the conductivity of the separator can be sufficiently secured by setting it to 30% by volume or less. Can do.

本発明の固体高分子型燃料電池用セパレータにおいては、上記金属粉に生成する不動態膜の導電性が非常に悪いため、黒鉛粉を混入させる。該黒鉛粉としては、特に限定されるものではなく、従来、樹脂に導電性を付与するために用いられている黒鉛粉を用いることができる。該黒鉛粉の粒径は、10〜500μmの範囲が好ましく、10〜100μmの範囲が更に好ましい。黒鉛粉の粒径が10μm以上であれば、セパレータが十分な導電率を確保することができ、500μm以下であれば、ポーラスになり難く、強度的に低くなり過ぎることがない。   In the separator for a polymer electrolyte fuel cell of the present invention, graphite powder is mixed because the passive film produced on the metal powder has very poor conductivity. The graphite powder is not particularly limited, and graphite powder conventionally used for imparting conductivity to a resin can be used. The particle size of the graphite powder is preferably in the range of 10 to 500 μm, more preferably in the range of 10 to 100 μm. If the particle size of the graphite powder is 10 μm or more, the separator can ensure sufficient conductivity, and if it is 500 μm or less, it is difficult to become porous and the strength does not become too low.

本発明の固体高分子型燃料電池用セパレータにおける上記黒鉛粉の含有率は、40〜60体積%の範囲が好ましい。セパレータ中の黒鉛粉含有率が40体積%以上であれば、セパレータの外表面に黒鉛粉を突出させ、セパレータの接触抵抗を十分に低減することができ、また、60体積%以下とすることで、セパレータの機械的強度を十分に確保することができる。   The content of the graphite powder in the polymer electrolyte fuel cell separator of the present invention is preferably in the range of 40 to 60% by volume. If the graphite powder content in the separator is 40% by volume or more, the graphite powder can be projected on the outer surface of the separator, and the contact resistance of the separator can be sufficiently reduced. The mechanical strength of the separator can be sufficiently ensured.

本発明の固体高分子型燃料電池用セパレータは、アノード用セパレータ及びカソード用セパレータとして用いることができ、例えば、アノード用セパレータ、アノード電極、触媒、固体高分子電解質膜、触媒、カソード電極、カソード用セパレータの順に積層して固体高分子型燃料電池を作製することができる。また、本発明の固体高分子型燃料電池用セパレータは、通常、表面に燃料及び酸素等を流すための流路を形成して用いられ、セルを積層して使用する場合は、両面に流路を形成して用いられるのが好ましい。該固体高分子型燃料電池は、セパレータの体積抵抗及び接触抵抗が低いため、電池特性に優れる。   The solid polymer fuel cell separator of the present invention can be used as an anode separator and a cathode separator. For example, an anode separator, an anode electrode, a catalyst, a solid polymer electrolyte membrane, a catalyst, a cathode electrode, and a cathode A polymer electrolyte fuel cell can be produced by laminating the separators in this order. The separator for a polymer electrolyte fuel cell of the present invention is usually used by forming a flow channel for flowing fuel, oxygen, etc. on the surface. It is preferable to form and use. The polymer electrolyte fuel cell is excellent in battery characteristics since the separator has low volume resistance and contact resistance.

次に、本発明の固体高分子型燃料電池用セパレータの製造方法を図を参照しながら詳細に説明する。図2は、本発明の製造方法の製造フローの一例を示している。図示例のように、(1)金属粉と、熱可塑性樹脂と、黒鉛粉とからなる混合物を均一に混合し、(2)該混合物を金型に充填し、(3)該混合物を金型内で加熱加圧成形することで、本発明の固体高分子型燃料電池用セパレータを製造することができる。なお、金型内での加熱加圧成形により、金属粉に不動態膜生成処理が施され、セパレータに十分な耐食性を付与することができる。ここで、加熱加圧成形における加熱温度は、280〜300℃の範囲が好ましく、圧力は、30〜60MPaの範囲が好ましい。また、特に限定されるものではないが、セパレータの導電性を十分に確保する観点から、不動態膜の膜厚が1〜3μmの範囲になるように加熱加圧成形を行うのが好ましい。   Next, a method for producing a solid polymer fuel cell separator of the present invention will be described in detail with reference to the drawings. FIG. 2 shows an example of the manufacturing flow of the manufacturing method of the present invention. As in the illustrated example, (1) a mixture of metal powder, thermoplastic resin, and graphite powder is uniformly mixed, (2) the mixture is filled into a mold, and (3) the mixture is molded into a mold. The separator for a polymer electrolyte fuel cell of the present invention can be produced by heating and pressure molding in the inside. In addition, the passive film production | generation process is performed to metal powder by the heat-press molding in a metal mold | die, and sufficient corrosion resistance can be provided to a separator. Here, the heating temperature in the heat and pressure molding is preferably in the range of 280 to 300 ° C., and the pressure is preferably in the range of 30 to 60 MPa. Although not particularly limited, from the viewpoint of sufficiently ensuring the conductivity of the separator, it is preferable to perform heat and pressure molding so that the thickness of the passive film is in the range of 1 to 3 μm.

以下に、実施例を挙げて本発明を更に詳しく説明するが、本発明は下記の実施例に何ら限定されるものではない。   Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

(実施例1)
アルミニウム粉[粒子径50μm]40体積%、黒鉛粉[日本カーボン製GA−40, 粒子径50μm]40体積%と、粉末状ポリフェニレンサルファイド[大日本インキ化学製DIC−PPS]20体積%とを均一に混合し、該混合物を金型(アルミニウム製, 最高金型温度400℃)に仕込み、油圧プレス機(最大加圧能力65t, 最大油圧力180kg/cm2)を用い加熱プレスして、厚さ5mmの導電性成形体を得た。得られた導電性成形体の体積抵抗率を三菱化学製ロレタス4端針式抵抗計で測定したところ、7.6×10-2Ω・cmであった。
Example 1
Aluminum powder [particle size 50 μm] 40% by volume, graphite powder [Nippon Carbon GA-40, particle size 50 μm] 40% by volume, and powdered polyphenylene sulfide [Dainippon Ink Chemical Co., Ltd. DIC-PPS] 20% by volume are uniform. The mixture is charged into a mold (aluminum, maximum mold temperature 400 ° C), heated and pressed using a hydraulic press (maximum pressurization capacity 65 t, maximum oil pressure 180 kg / cm 2 ) A 5 mm conductive molded body was obtained. The volume resistivity of the obtained conductive molded body was measured with a Loretus 4-end needle resistance meter manufactured by Mitsubishi Chemical Corporation, and it was 7.6 × 10 −2 Ω · cm.

(比較例1)
実施例1のセパレータと同じ寸法のSUS製セパレータを常法に従って試作し、該SUS製セパレータの体積抵抗率を測定したところ、1.0×10-5Ω・cmであった。しかしながら、該SUS製セパレータは、重量が実施例のセパレータの1.8倍であり、非常に重かった。
(Comparative Example 1)
A SUS separator having the same dimensions as the separator of Example 1 was prototyped according to a conventional method, and the volume resistivity of the SUS separator was measured and found to be 1.0 × 10 −5 Ω · cm. However, the SUS separator was 1.8 times as heavy as the separator of the example, and was very heavy.

本発明の固体高分子型燃料電池用セパレータの一例の断面図を示す。1 is a cross-sectional view of an example of a separator for a polymer electrolyte fuel cell according to the present invention. 本発明の固体高分子型燃料電池用セパレータの製造フローの一例を示す。An example of the manufacturing flow of the separator for polymer electrolyte fuel cells of this invention is shown.

符号の説明Explanation of symbols

1 固体高分子型燃料電池用セパレータ
2 金属粉
3 熱可塑性樹脂
4 黒鉛粉
5 不動態膜


DESCRIPTION OF SYMBOLS 1 Separator for polymer electrolyte fuel cells 2 Metal powder 3 Thermoplastic resin 4 Graphite powder 5 Passive membrane


Claims (7)

金属粉と、バインダーとしての熱可塑性樹脂と、黒鉛粉とからなる混合物をプレスしてなる固体高分子型燃料電池用セパレータ。   A polymer electrolyte fuel cell separator obtained by pressing a mixture of metal powder, a thermoplastic resin as a binder, and graphite powder. 前記金属粉が、不動態膜を生成することが可能な金属からなることを特徴とする請求項1に記載の固体高分子型燃料電池用セパレータ。   2. The polymer electrolyte fuel cell separator according to claim 1, wherein the metal powder is made of a metal capable of forming a passive film. 3. 前記不動態膜を生成することが可能な金属が、アルミニウム、ステンレス及びチタンからなる群から選択される少なくとも一種の金属であることを特徴とする請求項2に記載の固体高分子型燃料電池用セパレータ。   3. The polymer electrolyte fuel cell according to claim 2, wherein the metal capable of generating the passive film is at least one metal selected from the group consisting of aluminum, stainless steel, and titanium. Separator. 前記金属粉の含有率が20〜40体積%であることを特徴とする請求項1に記載の固体高分子型燃料電池用セパレータ。   2. The solid polymer fuel cell separator according to claim 1, wherein the content of the metal powder is 20 to 40% by volume. 前記熱可塑性樹脂の含有率が20〜30体積%であることを特徴とする請求項1に記載の固体高分子型燃料電池用セパレータ。   2. The polymer electrolyte fuel cell separator according to claim 1, wherein a content of the thermoplastic resin is 20 to 30% by volume. 3. 前記黒鉛粉の含有率が40〜60体積%であることを特徴とする請求項1に記載の固体高分子型燃料電池用セパレータ。   2. The solid polymer fuel cell separator according to claim 1, wherein a content of the graphite powder is 40 to 60% by volume. 金属粉と、バインダーとしての熱可塑性樹脂と、黒鉛粉とからなる混合物を溝形状を有する金型に充填し、該混合物を加熱加圧焼成して、金属粉に不動態膜生成処理を施しつつ成形することを特徴とする固体高分子型燃料電池用セパレータの製造方法。


Filling a mold having a groove shape with a mixture of metal powder, a thermoplastic resin as a binder and graphite powder, heating and pressing the mixture, and subjecting the metal powder to a passive film generation treatment A method for producing a polymer electrolyte fuel cell separator, comprising molding.


JP2004182251A 2004-06-21 2004-06-21 Separator for solid polymer fuel cell and its manufacturing method Withdrawn JP2006004853A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008123828A (en) * 2006-11-13 2008-05-29 Tokai Carbon Co Ltd Separator material for polymer electrolyte fuel cell and its manufacturing method
US11205784B2 (en) 2018-04-24 2021-12-21 Toyota Jidosha Kabushiki Kaisha Fuel cell and method for manufacturing separator for fuel cell including conductive particles and carbon fibers buried in projecting parts

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008123828A (en) * 2006-11-13 2008-05-29 Tokai Carbon Co Ltd Separator material for polymer electrolyte fuel cell and its manufacturing method
US11205784B2 (en) 2018-04-24 2021-12-21 Toyota Jidosha Kabushiki Kaisha Fuel cell and method for manufacturing separator for fuel cell including conductive particles and carbon fibers buried in projecting parts

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