JP2013033650A - Membrane electrode assembly for solid electrolyte fuel cell - Google Patents

Membrane electrode assembly for solid electrolyte fuel cell Download PDF

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JP2013033650A
JP2013033650A JP2011169345A JP2011169345A JP2013033650A JP 2013033650 A JP2013033650 A JP 2013033650A JP 2011169345 A JP2011169345 A JP 2011169345A JP 2011169345 A JP2011169345 A JP 2011169345A JP 2013033650 A JP2013033650 A JP 2013033650A
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electrolyte membrane
electrode
polymer electrolyte
outer peripheral
peripheral end
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Masahiro Mori
昌弘 毛里
Jun Takano
純 高野
Yasunori Kotani
保紀 小谷
Hiroaki Ota
広明 太田
Shuji Sato
修二 佐藤
Taisuke Okonogi
泰介 小此木
Masashi Sugishita
昌史 杉下
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Honda Motor Co Ltd
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    • 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

Abstract

PROBLEM TO BE SOLVED: To provide a membrane electrode assembly that separates a hydrogen peroxide generation region from an electrode end and prevents degradation of an electrolyte membrane and the like effectively with a simple configuration.SOLUTION: A membrane electrode assembly 10 has an anode electrode 20, and a cathode electrode 22, provided on two respective sides of a solid polymer electrolyte membrane 18. An outer peripheral end of the cathode electrode 22 projects outward beyond an outer peripheral end of the anode electrode 20. A resin frame member 24 is provided so as to surround an outer periphery of the solid polymer electrolyte membrane 18. In the membrane electrode assembly 10, an outer peripheral end 18c of the solid polymer electrolyte membrane 18 projects outward beyond the outer peripheral end of the cathode electrode 22, and is bended toward the anode electrode 20.

Description

本発明は、電解質膜の両側にそれぞれアノード電極及びカソード電極が設けられ、前記カソード電極の外周端部は、前記アノード電極の外周端部よりも外側に突出するとともに、前記電解質膜の外周を周回して樹脂製枠部材が設けられる固体電解質型燃料電池用電解質膜・電極構造体に関する。   According to the present invention, an anode electrode and a cathode electrode are provided on both sides of an electrolyte membrane, and an outer peripheral end portion of the cathode electrode protrudes outward from an outer peripheral end portion of the anode electrode, and circulates around the outer periphery of the electrolyte membrane. The present invention relates to an electrolyte membrane / electrode structure for a solid oxide fuel cell provided with a resin frame member.

例えば、固体高分子型燃料電池は、高分子イオン交換膜からなる固体高分子電解質膜を採用している。この燃料電池は、固体高分子電解質膜の両側に、それぞれ電極触媒（電極触媒層）と多孔質カーボン（ガス拡散層）からなるアノード電極及びカソード電極を配設した電解質膜・電極構造体（ＭＥＡ）を、セパレータ（バイポーラ板）によって挟持する発電セルを構成している。通常、燃料電池では、発電セルを所定の数だけ積層した燃料電池スタックが、例えば、車載用燃料電池スタックとして使用されている。   For example, a solid polymer fuel cell employs a solid polymer electrolyte membrane made of a polymer ion exchange membrane. This fuel cell has an electrolyte membrane / electrode structure (MEA) in which an anode electrode and a cathode electrode each made of an electrode catalyst (electrode catalyst layer) and porous carbon (gas diffusion layer) are disposed on both sides of a solid polymer electrolyte membrane. ) Is constituted by a separator (bipolar plate). Normally, in a fuel cell, a fuel cell stack in which a predetermined number of power generation cells are stacked is used as, for example, an in-vehicle fuel cell stack.

この種の電解質膜・電極構造体では、一方の電極が固体高分子電解質膜よりも小さな表面積に設定されるとともに、他方の電極が前記固体高分子電解質膜と同一の表面積に設定される、所謂、段差型ＭＥＡを構成する場合がある。その際、外部に露呈する電解質膜を保護するとともに、ＭＥＡの取り扱い作業性及びシール性を向上させるため、電解質膜・電極構造体の外周に枠部材（樹脂枠部材）を設ける工夫がなされている。   In this type of electrolyte membrane / electrode structure, one electrode is set to have a smaller surface area than the solid polymer electrolyte membrane, and the other electrode is set to the same surface area as the solid polymer electrolyte membrane. In some cases, a stepped MEA is formed. At that time, in order to protect the electrolyte membrane exposed to the outside and improve the handling workability and sealing performance of the MEA, a device has been devised to provide a frame member (resin frame member) on the outer periphery of the electrolyte membrane / electrode structure. .

例えば、特許文献１に開示されている膜電極組立体（電解質膜・電極構造体）は、図５に示すように、高分子電解質膜１、前記高分子電解質膜１の一方の面側に設けられる第１の電極層２、前記第１の電極層２の該高分子電解質膜１とは反対側に設けられる第１のガス拡散層３、該高分子電解質膜１の他方の面側に設けられる第２の電極層４、及び前記第２の電極層４の該高分子電解質膜１とは反対側に設けられる第２のガス拡散層５を含む膜電極接合体６を備えている。   For example, the membrane electrode assembly (electrolyte membrane / electrode structure) disclosed in Patent Document 1 is provided on one surface side of the polymer electrolyte membrane 1 and the polymer electrolyte membrane 1 as shown in FIG. The first electrode layer 2 to be formed, the first gas diffusion layer 3 provided on the opposite side of the polymer electrolyte membrane 1 of the first electrode layer 2, and provided on the other surface side of the polymer electrolyte membrane 1 And a membrane electrode assembly 6 including a second gas diffusion layer 5 provided on the opposite side of the second electrode layer 4 from the polymer electrolyte membrane 1.

膜電極接合体６には、高分子電解質膜１の外周縁の全部並びに第１及び第２のガス拡散層３、５の外周縁の少なくとも一部であって前記高分子電解質膜１の側を包囲するように、樹脂枠７が設けられている。   The membrane electrode assembly 6 includes the entire outer periphery of the polymer electrolyte membrane 1 and at least a part of the outer periphery of the first and second gas diffusion layers 3 and 5, and the polymer electrolyte membrane 1 side. A resin frame 7 is provided so as to surround it.

第１のガス拡散層３及び第１の電極層２は、前記第１のガス拡散層３の外周縁全体が高分子電解質膜１の外周縁の範囲内に収まるとともに、前記第１の電極層２の外周縁全周に亘って該第１の電極層２の外周縁と該高分子電解質膜１の外周縁との間に該高分子電解質膜１の表面領域が残るように、該高分子電解質膜１の表面上に配置されている。   The first gas diffusion layer 3 and the first electrode layer 2 are configured such that the entire outer periphery of the first gas diffusion layer 3 is within the range of the outer periphery of the polymer electrolyte membrane 1 and the first electrode layer 2 so that the surface region of the polymer electrolyte membrane 1 remains between the outer periphery of the first electrode layer 2 and the outer periphery of the polymer electrolyte membrane 1 over the entire outer periphery of the first electrode layer 2. It is disposed on the surface of the electrolyte membrane 1.

第２のガス拡散層５は、高分子電解質膜１の外周縁全周に亘って該表面領域とは反対側の少なくとも一部にまで延在しており、さらに樹脂枠７は、該表面領域の少なくとも一部に固着されている。   The second gas diffusion layer 5 extends to the at least part of the opposite side of the surface region over the entire outer periphery of the polymer electrolyte membrane 1, and the resin frame 7 further includes the surface region. It is fixed to at least a part of.

また、特許文献２に開示されている電解質膜−電極接合体は、電解質膜と、前記電解質膜の一方の側に配置されたカソード触媒層と、前記電解質膜の他方の側に配置されたアノード触媒層と、両触媒層の端部の周囲の少なくとも一部に配置されるガスケット層が一体化されてなるガスケット構造体とを有している。そして、電解質膜の両面にガス拡散層を備え、前記電解質膜の両面に備えられた両ガス拡散層は面積が異なり、少なくともガス拡散層の面積が小さい側の前記電解質膜の外周部とガスケット構造体とが接合されている。   Further, an electrolyte membrane-electrode assembly disclosed in Patent Document 2 includes an electrolyte membrane, a cathode catalyst layer disposed on one side of the electrolyte membrane, and an anode disposed on the other side of the electrolyte membrane. It has a catalyst layer and a gasket structure formed by integrating a gasket layer disposed at least at a part around the ends of both catalyst layers. Further, gas diffusion layers are provided on both surfaces of the electrolyte membrane, the gas diffusion layers provided on both surfaces of the electrolyte membrane have different areas, and at least the outer peripheral portion of the electrolyte membrane and the gasket structure on the side where the area of the gas diffusion layer is small The body is joined.

特開２００８−４１３３７号公報JP 2008-41337 A 特開２００７−６６７６６号公報JP 2007-66766 A

上記の特許文献１及び特許文献２では、一方の電極が固体高分子電解質膜よりも小さな表面積に設定されるため、前記固体高分子電解質膜の外周縁部が露呈している。従って、燃料電池システムの運転停止時に、燃料ガスがアノード側からカソード側に固体高分子電解質膜を透過する一方、酸化剤ガスが前記カソード側から前記アノード側に前記固体高分子電解質膜を透過する場合がある。   In Patent Document 1 and Patent Document 2 described above, since one electrode is set to have a smaller surface area than the solid polymer electrolyte membrane, the outer peripheral edge of the solid polymer electrolyte membrane is exposed. Therefore, when the fuel cell system is shut down, fuel gas permeates the solid polymer electrolyte membrane from the anode side to the cathode side, while oxidant gas permeates the solid polymer electrolyte membrane from the cathode side to the anode side. There is a case.

このため、アノード側及びカソード側では、水素と酸素とが反応して過酸化水素（Ｈ２Ｏ２）が発生し易い（Ｈ２＋Ｏ２→Ｈ２Ｏ２）。この過酸化水素は、電極中のカーボン担体や白金（Ｐｔ）上で分解し、例えば、ヒドロキシラジカル（・ＯＨ）が発生する。これにより、固体高分子電解質膜及び電極を劣化させるという問題がある。 For this reason, hydrogen and oxygen react with each other on the anode side and the cathode side to easily generate hydrogen peroxide (H 2 O 2 ) (H 2 + O 2 → H 2 O 2 ). This hydrogen peroxide is decomposed on the carbon support or platinum (Pt) in the electrode, and for example, a hydroxy radical (.OH) is generated. Thereby, there exists a problem of degrading a solid polymer electrolyte membrane and an electrode.

過酸化水素は、図６に示すように、特に０．２Ｖ以下の低電位領域で急増している。従って、アノード側の触媒塗布面積が大きいと、カソード側で低電位領域が拡大してしまい、ＭＥＡ端部に燃料ガス及び酸化剤ガスが滞留し易い場合には、膜劣化が著しいという問題がある。   As shown in FIG. 6, hydrogen peroxide has increased rapidly particularly in a low potential region of 0.2 V or less. Therefore, when the catalyst application area on the anode side is large, the low potential region is enlarged on the cathode side, and when the fuel gas and the oxidant gas tend to stay at the end of the MEA, there is a problem that the film deterioration is significant. .

本発明は、この種の問題を解決するものであり、過酸化水素が発生する領域を電極端部から離間させることができ、簡単な構成で、電解質膜等の劣化を有効に抑制することが可能な固体電解質型燃料電池用電解質膜・電極構造体を提供することを目的とする。   The present invention solves this type of problem, and the region where hydrogen peroxide is generated can be separated from the end of the electrode, and deterioration of the electrolyte membrane and the like can be effectively suppressed with a simple configuration. An object of the present invention is to provide an electrolyte membrane / electrode structure for a solid oxide fuel cell.

本発明は、電解質膜の両側にそれぞれアノード電極及びカソード電極が設けられ、前記カソード電極の外周端部は、前記アノード電極の外周端部よりも外側に突出するとともに、前記電解質膜の外周を周回して樹脂製枠部材が設けられる固体電解質型燃料電池用電解質膜・電極構造体に関するものである。   According to the present invention, an anode electrode and a cathode electrode are provided on both sides of an electrolyte membrane, and an outer peripheral end portion of the cathode electrode protrudes outward from an outer peripheral end portion of the anode electrode, and circulates around the outer periphery of the electrolyte membrane. The present invention relates to an electrolyte membrane / electrode structure for a solid oxide fuel cell provided with a resin frame member.

この固体電解質型燃料電池用電解質膜・電極構造体では、電解質膜の外周端部は、カソード電極の外周端部よりも外側に突出するとともに、アノード電極側に湾曲形成されている。   In this electrolyte membrane / electrode structure for a solid oxide fuel cell, the outer peripheral end of the electrolyte membrane protrudes outward from the outer peripheral end of the cathode electrode, and is curved toward the anode electrode.

本発明によれば、アノード電極の電極面積が、カソード電極の電極面積よりも小さく設定されることにより、カソード側の低電位領域を縮小させることができ、発生する過酸化水素量を削減することが可能になる。   According to the present invention, by setting the electrode area of the anode electrode to be smaller than the electrode area of the cathode electrode, the low potential region on the cathode side can be reduced, and the amount of generated hydrogen peroxide can be reduced. Is possible.

しかも、電解質膜の外周端部は、アノード電極側に湾曲形成されている。従って、過酸化水素が発生する領域を、カソード電極の端部から離間させることができ、簡単な構成で、前記カソード電極及び電解質膜等の劣化を良好に抑制することが可能になる。   Moreover, the outer peripheral end of the electrolyte membrane is curved toward the anode electrode side. Therefore, the region where hydrogen peroxide is generated can be separated from the end portion of the cathode electrode, and deterioration of the cathode electrode and the electrolyte membrane can be satisfactorily suppressed with a simple configuration.

本発明の実施形態に係る電解質膜・電極構造体が組み込まれる固体高分子型燃料電池の要部分解斜視図である。1 is an exploded perspective view of a main part of a polymer electrolyte fuel cell in which an electrolyte membrane / electrode structure according to an embodiment of the invention is incorporated. 前記燃料電池の、図１中、ＩＩ−ＩＩ線断面図である。It is the II-II sectional view taken on the line of the said fuel cell in FIG. 前記電解質膜・電極構造体に樹脂製枠部材を射出成形するための射出成形機の説明図である。It is explanatory drawing of the injection molding machine for carrying out the injection molding of the resin-made frame members to the said electrolyte membrane and electrode structure. 前記電解質膜・電極構造体の要部説明図である。It is principal part explanatory drawing of the said electrolyte membrane and electrode structure. 特許文献１に開示されている膜電極組立体の説明図である。It is explanatory drawing of the membrane electrode assembly currently disclosed by patent document 1. FIG. 電位とＨ２Ｏ２の発生率との関係説明図である。It is a relationship diagram between the incidence of potential and H 2 O 2.

図１及び図２に示すように、本発明の実施形態に係る電解質膜・電極構造体１０が組み込まれる固体高分子型燃料電池１２は、前記電解質膜・電極構造体１０を第１セパレータ１４及び第２セパレータ１６で挟持する。第１セパレータ１４及び第２セパレータ１６は、例えば、鋼板、ステンレス鋼板、アルミニウム板、めっき処理鋼板、あるいはその金属表面に防食用の表面処理を施した金属板や、カーボン部材等で構成されている。   As shown in FIGS. 1 and 2, the polymer electrolyte fuel cell 12 incorporating the electrolyte membrane / electrode structure 10 according to the embodiment of the present invention includes the first membrane 14 and the electrolyte membrane / electrode structure 10. It is clamped by the second separator 16. The first separator 14 and the second separator 16 are made of, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, a metal plate whose surface is subjected to anticorrosion treatment, a carbon member, or the like. .

図２に示すように、電解質膜・電極構造体１０は、例えば、パーフルオロスルホン酸の薄膜に水が含浸された固体高分子電解質膜１８と、前記固体高分子電解質膜１８を挟持するアノード電極２０及びカソード電極２２とを備える。固体高分子電解質膜１８は、フッ素系電解質の他、ＨＣ（炭化水素）系電解質が使用される。   As shown in FIG. 2, the electrolyte membrane / electrode structure 10 includes, for example, a solid polymer electrolyte membrane 18 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode electrode sandwiching the solid polymer electrolyte membrane 18 20 and the cathode electrode 22. The solid polymer electrolyte membrane 18 uses an HC (hydrocarbon) electrolyte in addition to a fluorine electrolyte.

カソード電極２２の外周端部は、アノード電極２０の外周端部よりも外側に突出するとともに、前記アノード電極２０は、固体高分子電解質膜１８の一方の面１８ａに配置される。アノード電極２０は、固体高分子電解質膜１８の外周を額縁状に露呈させる。カソード電極２２は、固体高分子電解質膜１８の他方の面１８ｂに配置され、前記固体高分子電解質膜１８の外周端部１８ｃは、前記カソード電極２２の外周端部よりも外方に突出する。   The outer peripheral end of the cathode electrode 22 protrudes outward from the outer peripheral end of the anode electrode 20, and the anode electrode 20 is disposed on one surface 18 a of the solid polymer electrolyte membrane 18. The anode electrode 20 exposes the outer periphery of the solid polymer electrolyte membrane 18 in a frame shape. The cathode electrode 22 is disposed on the other surface 18 b of the solid polymer electrolyte membrane 18, and the outer peripheral end portion 18 c of the solid polymer electrolyte membrane 18 protrudes outward from the outer peripheral end portion of the cathode electrode 22.

アノード電極２０は、固体高分子電解質膜１８の面１８ａに接合される電極触媒層２０ａと、前記電極触媒層２０ａに中間層（下地層）２０ｂを介して積層されるガス拡散層２０ｃとを設ける。電極触媒層２０ａと中間層２０ｂとは、ガス拡散層２０ｃの端部まで伸びている。カソード電極２２は、固体高分子電解質膜１８の面１８ｂに接合される電極触媒層２２ａと、前記電極触媒層２２ａに中間層（下地層）２２ｂを介して積層されるガス拡散層２２ｃとを設ける。電極触媒層２２ａと中間層２２ｂとは、ガス拡散層２２ｃの端部まで伸びている。なお、中間層２０ｂ、２２ｂは、設けなくてもよい。   The anode electrode 20 is provided with an electrode catalyst layer 20a bonded to the surface 18a of the solid polymer electrolyte membrane 18, and a gas diffusion layer 20c laminated on the electrode catalyst layer 20a via an intermediate layer (underlayer) 20b. . The electrode catalyst layer 20a and the intermediate layer 20b extend to the end of the gas diffusion layer 20c. The cathode electrode 22 is provided with an electrode catalyst layer 22a joined to the surface 18b of the solid polymer electrolyte membrane 18, and a gas diffusion layer 22c laminated on the electrode catalyst layer 22a via an intermediate layer (underlayer) 22b. . The electrode catalyst layer 22a and the intermediate layer 22b extend to the end of the gas diffusion layer 22c. The intermediate layers 20b and 22b need not be provided.

電極触媒層２０ａ、２２ａは、カーボンブラックに白金粒子を担持した触媒粒子を形成し、イオン導伝性バインダーとして高分子電解質を使用し、この高分子電解質の溶液中に前記触媒粒子を均一に混合して作製された触媒ペーストを、固体高分子電解質膜１８の両面に印刷、塗布又は転写することによって構成される。アノード側の電極触媒層２０ａとカソード側の電極触媒層２２ａとの大小関係を維持した状態で、最端部に接着層を設けてもよい。   The electrode catalyst layers 20a and 22a form catalyst particles in which platinum particles are supported on carbon black, use a polymer electrolyte as an ion conductive binder, and uniformly mix the catalyst particles in a solution of the polymer electrolyte. The catalyst paste produced in this way is configured by printing, coating or transferring on both sides of the solid polymer electrolyte membrane 18. An adhesive layer may be provided at the outermost end while maintaining the magnitude relationship between the anode-side electrode catalyst layer 20a and the cathode-side electrode catalyst layer 22a.

中間層２０ｂ、２２ｂは、カーボンブラック及びＦＥＰ（四フッ化エチレン−六フッ化プロピレン共重合体）粒子とカーボンナノチューブをペースト状にした後、ガス拡散層２０ｃ、２２ｃに塗布される。ガス拡散層２０ｃ、２２ｃは、カーボンペーパ等からなるとともに、前記ガス拡散層２０ｃの平面は、前記ガス拡散層２２ｃの平面よりも小さく設定される。   The intermediate layers 20b and 22b are formed by pasting carbon black, FEP (tetrafluoroethylene-hexafluoropropylene copolymer) particles, and carbon nanotubes, and then applied to the gas diffusion layers 20c and 22c. The gas diffusion layers 20c and 22c are made of carbon paper or the like, and the plane of the gas diffusion layer 20c is set smaller than the plane of the gas diffusion layer 22c.

電解質膜・電極構造体１０は、固体高分子電解質膜１８の外周を周回する樹脂製枠部材２４を備える。樹脂製枠部材２４は、例えば、ＰＰＳ（ポリフェニレンサルファイド）やＰＰＡ（ポリフタルアミド）等で構成される他、弾性を有するゴム部材で構成されてもよい。固体高分子電解質膜１８の外周端部１８ｃは、アノード電極２０側に湾曲形成されて樹脂製枠部材２４内に埋設される。   The electrolyte membrane / electrode structure 10 includes a resin frame member 24 that goes around the outer periphery of the solid polymer electrolyte membrane 18. The resin frame member 24 may be made of, for example, a rubber member having elasticity in addition to PPS (polyphenylene sulfide), PPA (polyphthalamide), or the like. The outer peripheral end portion 18 c of the solid polymer electrolyte membrane 18 is curvedly formed on the anode electrode 20 side and embedded in the resin frame member 24.

図１に示すように、燃料電池１２の矢印Ｂ方向（図１中、水平方向）の一端縁部には、積層方向である矢印Ａ方向に互いに連通して、酸化剤ガス、例えば、酸素含有ガスを供給するための酸化剤ガス入口連通孔３０ａ、冷却媒体を供給するための冷却媒体入口連通孔３２ａ、及び燃料ガス、例えば、水素含有ガスを排出するための燃料ガス出口連通孔３４ｂが、矢印Ｃ方向（鉛直方向）に配列して設けられる。   As shown in FIG. 1, one end edge of the fuel cell 12 in the arrow B direction (horizontal direction in FIG. 1) communicates with each other in the arrow A direction, which is the stacking direction, and contains an oxidant gas, for example, oxygen An oxidant gas inlet communication hole 30a for supplying gas, a cooling medium inlet communication hole 32a for supplying a cooling medium, and a fuel gas outlet communication hole 34b for discharging a fuel gas, for example, a hydrogen-containing gas, Arranged in the direction of arrow C (vertical direction).

燃料電池１２の矢印Ｂ方向の他端縁部には、矢印Ａ方向に互いに連通して、燃料ガスを供給するための燃料ガス入口連通孔３４ａ、冷却媒体を排出するための冷却媒体出口連通孔３２ｂ、及び酸化剤ガスを排出するための酸化剤ガス出口連通孔３０ｂが、矢印Ｃ方向に配列して設けられる。   The other end edge of the fuel cell 12 in the direction of arrow B communicates with each other in the direction of arrow A, a fuel gas inlet communication hole 34a for supplying fuel gas, and a cooling medium outlet communication hole for discharging the cooling medium. 32b and an oxidant gas outlet communication hole 30b for discharging the oxidant gas are arranged in the direction of arrow C.

第２セパレータ１６の電解質膜・電極構造体１０に向かう面１６ａには、酸化剤ガス入口連通孔３０ａと酸化剤ガス出口連通孔３０ｂとに連通する酸化剤ガス流路３６が設けられる。   An oxidant gas flow path 36 that communicates with the oxidant gas inlet communication hole 30a and the oxidant gas outlet communication hole 30b is provided on the surface 16a of the second separator 16 facing the electrolyte membrane / electrode structure 10.

第１セパレータ１４の電解質膜・電極構造体１０に向かう面１４ａには、燃料ガス入口連通孔３４ａと燃料ガス出口連通孔３４ｂとに連通する燃料ガス流路３８が形成される。第１セパレータ１４の面１４ｂと第２セパレータ１６の面１６ｂとの間には、冷却媒体入口連通孔３２ａと冷却媒体出口連通孔３２ｂとに連通する冷却媒体流路４０が形成される。   A fuel gas flow path 38 communicating with the fuel gas inlet communication hole 34 a and the fuel gas outlet communication hole 34 b is formed on the surface 14 a of the first separator 14 facing the electrolyte membrane / electrode structure 10. Between the surface 14 b of the first separator 14 and the surface 16 b of the second separator 16, a cooling medium flow path 40 communicating with the cooling medium inlet communication hole 32 a and the cooling medium outlet communication hole 32 b is formed.

図１及び図２に示すように、第１セパレータ１４の面１４ａ、１４ｂには、この第１セパレータ１４の外周端部を周回して、第１シール部材４２が一体化されるとともに、第２セパレータ１６の面１６ａ、１６ｂには、この第２セパレータ１６の外周端部を周回して、第２シール部材４４が一体化される。   As shown in FIGS. 1 and 2, the first seal member 42 is integrated with the surfaces 14 a and 14 b of the first separator 14 around the outer peripheral end of the first separator 14, and the second The second seal member 44 is integrated with the surfaces 16 a and 16 b of the separator 16 around the outer peripheral end of the second separator 16.

図２に示すように、第１シール部材４２は、電解質膜・電極構造体１０の樹脂製枠部材２４に当接する第１凸状シール４２ａと、第１セパレータ１４と第２セパレータ１６との間に介装される第２凸状シール４２ｂとを有する。第２シール部材４４は、平面シールを構成する。なお、第２凸状シール４２ｂに代えて、第２シール部材４４に凸状シール（図示せず）を設けてもよい。   As shown in FIG. 2, the first seal member 42 includes a first convex seal 42 a that contacts the resin frame member 24 of the electrolyte membrane / electrode structure 10, and a gap between the first separator 14 and the second separator 16. And a second convex seal 42b interposed therebetween. The second seal member 44 constitutes a flat seal. Instead of the second convex seal 42b, the second seal member 44 may be provided with a convex seal (not shown).

第１及び第２シール部材４２、４４には、例えば、ＥＰＤＭ、ＮＢＲ、フッ素ゴム、シリコーンゴム、フロロシリコーンゴム、ブチルゴム、天然ゴム、スチレンゴム、クロロプレーン又はアクリルゴム等のシール材、クッション材、あるいはパッキン材が用いられる。   The first and second sealing members 42 and 44 include, for example, EPDM, NBR, fluorine rubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene or acrylic rubber, a cushioning material, Alternatively, a packing material is used.

図１に示すように、第１セパレータ１４には、燃料ガス入口連通孔３４ａを燃料ガス流路３８に連通する供給孔部４６と、前記燃料ガス流路３８を燃料ガス出口連通孔３４ｂに連通する排出孔部４８とが形成される。   As shown in FIG. 1, the first separator 14 has a supply hole portion 46 that communicates the fuel gas inlet communication hole 34a with the fuel gas passage 38, and the fuel gas passage 38 communicates with the fuel gas outlet communication hole 34b. A discharge hole 48 is formed.

このように構成される燃料電池１２において、本発明の実施形態に係る電解質膜・電極構造体１０の製造方法について、以下に説明する。   In the fuel cell 12 configured as described above, a method for manufacturing the electrolyte membrane / electrode structure 10 according to the embodiment of the present invention will be described below.

先ず、図３に示すように、段差ＭＥＡ５０が作製された後、前記段差ＭＥＡ５０が射出成形機５２に配置される。段差ＭＥＡ５０は、具体的には、固体高分子電解質膜１８の両方の面１８ａ、１８ｂには、電極触媒層２０ａ、２２ａが塗布される一方、ガス拡散層２０ｃ、２２ｃには、撥水剤とカーボン粒子の混合物からなる中間層２０ｂ、２２ｂが塗布される。   First, as shown in FIG. 3, after the step MEA 50 is manufactured, the step MEA 50 is arranged in the injection molding machine 52. Specifically, the step MEA 50 has electrode catalyst layers 20a and 22a applied to both surfaces 18a and 18b of the solid polymer electrolyte membrane 18, while a water repellent agent is applied to the gas diffusion layers 20c and 22c. Intermediate layers 20b and 22b made of a mixture of carbon particles are applied.

そして、固体高分子電解質膜１８の面１８ａ側に、すなわち、電極触媒層２０ａに、中間層２０ｂを対向させてガス拡散層２０ｃが配置されるとともに、前記固体高分子電解質膜１８の面１８ｂに、すなわち、電極触媒層２２ａに、中間層２２ｂを対向させてガス拡散層２２ｃが配置される。これらが一体に積層されてホットプレス処理されることにより、段差ＭＥＡ５０が作製される。固体高分子電解質膜１８の外周端部１８ｃは、平坦状に延在している。なお、この外周端部１８ｃは、予めアノード電極２０側に、該アノード電極２０の最端部を起点にして湾曲成形してもよい。   A gas diffusion layer 20c is disposed on the surface 18a side of the solid polymer electrolyte membrane 18, that is, the electrode catalyst layer 20a with the intermediate layer 20b facing the surface, and on the surface 18b of the solid polymer electrolyte membrane 18. That is, the gas diffusion layer 22c is disposed with the intermediate layer 22b facing the electrode catalyst layer 22a. The step MEA 50 is manufactured by stacking these together and performing hot pressing. The outer peripheral end 18c of the solid polymer electrolyte membrane 18 extends in a flat shape. The outer peripheral end portion 18c may be curved and formed in advance on the anode electrode 20 side, starting from the outermost end portion of the anode electrode 20.

射出成形機５２は、第１型部材５４と第２型部材５６とを備えるとともに、これらの間には、キャビティ５８が形成される。キャビティ５８は、樹脂製枠部材２４の形状に対応している。第２型部材５６には、固体高分子電解質膜１８の外周端部１８ｃに向かって開口する射出口６０が形成される。   The injection molding machine 52 includes a first mold member 54 and a second mold member 56, and a cavity 58 is formed between them. The cavity 58 corresponds to the shape of the resin frame member 24. The second mold member 56 is formed with an injection port 60 that opens toward the outer peripheral end 18 c of the solid polymer electrolyte membrane 18.

段差ＭＥＡ５０がキャビティ５８に配置されるとともに、第１型部材５４と第２型部材５６とが型締めされた状態で、前記第２型部材５６の射出口６０から前記キャビティ５８に溶融樹脂が射出される。このため、溶融樹脂は、固体高分子電解質膜１８の外周端部１８ｃをアノード電極２０側に湾曲させるようにして、キャビティ５８に充填される。従って、溶融樹脂が固化することにより、樹脂製枠部材２４が段差ＭＥＡ５０に一体成形される。   While the step MEA 50 is disposed in the cavity 58 and the first mold member 54 and the second mold member 56 are clamped, molten resin is injected into the cavity 58 from the injection port 60 of the second mold member 56. Is done. Therefore, the molten resin is filled in the cavity 58 so that the outer peripheral end portion 18c of the solid polymer electrolyte membrane 18 is curved toward the anode electrode 20 side. Accordingly, when the molten resin is solidified, the resin frame member 24 is integrally formed with the step MEA 50.

その際、固体高分子電解質膜１８の外周端部１８ｃは、アノード電極２０側に湾曲した形状に保持される。これにより、本実施形態に係る電解質膜・電極構造体１０が製造される（図２参照）。   At that time, the outer peripheral end portion 18c of the solid polymer electrolyte membrane 18 is held in a shape curved toward the anode electrode 20 side. As a result, the electrolyte membrane / electrode structure 10 according to the present embodiment is manufactured (see FIG. 2).

このように構成される燃料電池１２の動作について、以下に説明する。   The operation of the fuel cell 12 configured as described above will be described below.

先ず、図１に示すように、酸化剤ガス入口連通孔３０ａに酸素含有ガス等の酸化剤ガスが供給されるとともに、燃料ガス入口連通孔３４ａに水素含有ガス等の燃料ガスが供給される。さらに、冷却媒体入口連通孔３２ａに純水やエチレングリコール、オイル等の冷却媒体が供給される。   First, as shown in FIG. 1, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 30a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 34a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 32a.

このため、酸化剤ガスは、酸化剤ガス入口連通孔３０ａから第２セパレータ１６の酸化剤ガス流路３６に導入され、矢印Ｂ方向に移動して電解質膜・電極構造体１０のカソード電極２２に供給される。一方、燃料ガスは、燃料ガス入口連通孔３４ａから供給孔部４６を通って第１セパレータ１４の燃料ガス流路３８に導入される。燃料ガスは、燃料ガス流路３８に沿って矢印Ｂ方向に移動し、電解質膜・電極構造体１０のアノード電極２０に供給される。   For this reason, the oxidant gas is introduced into the oxidant gas flow path 36 of the second separator 16 from the oxidant gas inlet communication hole 30a and moves in the direction of arrow B to the cathode electrode 22 of the electrolyte membrane / electrode structure 10. Supplied. On the other hand, the fuel gas is introduced from the fuel gas inlet communication hole 34 a through the supply hole 46 into the fuel gas flow path 38 of the first separator 14. The fuel gas moves in the direction of arrow B along the fuel gas flow path 38 and is supplied to the anode electrode 20 of the electrolyte membrane / electrode structure 10.

従って、各電解質膜・電極構造体１０では、カソード電極２２に供給される酸化剤ガスと、アノード電極２０に供給される燃料ガスとが、電極触媒層内で電気化学反応により消費されて発電が行われる。   Therefore, in each electrolyte membrane / electrode structure 10, the oxidant gas supplied to the cathode electrode 22 and the fuel gas supplied to the anode electrode 20 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Done.

次いで、カソード電極２２に供給されて消費された酸化剤ガスは、酸化剤ガス出口連通孔３０ｂに沿って矢印Ａ方向に排出される。同様に、アノード電極２０に供給されて消費された燃料ガスは、排出孔部４８を通り燃料ガス出口連通孔３４ｂに沿って矢印Ａ方向に排出される。   Next, the oxidant gas consumed by being supplied to the cathode electrode 22 is discharged in the direction of arrow A along the oxidant gas outlet communication hole 30b. Similarly, the fuel gas consumed by being supplied to the anode electrode 20 passes through the discharge hole 48 and is discharged in the direction of arrow A along the fuel gas outlet communication hole 34b.

また、冷却媒体入口連通孔３２ａに供給された冷却媒体は、第１セパレータ１４と第２セパレータ１６との間の冷却媒体流路４０に導入された後、矢印Ｂ方向に流通する。この冷却媒体は、電解質膜・電極構造体１０を冷却した後、冷却媒体出口連通孔３２ｂから排出される。   The cooling medium supplied to the cooling medium inlet communication hole 32a is introduced into the cooling medium flow path 40 between the first separator 14 and the second separator 16, and then flows in the direction of arrow B. The cooling medium is discharged from the cooling medium outlet communication hole 32b after the electrolyte membrane / electrode structure 10 is cooled.

この場合、本実施形態では、アノード電極２０の電極面積が、カソード電極２２の電極面積よりも小さく設定されている。このため、図２に示すように、アノード電極端は、カソード電極端よりも小さく形成され、ヒドロキシラジカル（・ＯＨ）の前駆体であるＨ２Ｏ２が存在し易い電位（低電位領域）を縮小させることができる。 In this case, in this embodiment, the electrode area of the anode electrode 20 is set smaller than the electrode area of the cathode electrode 22. For this reason, as shown in FIG. 2, the anode electrode end is formed smaller than the cathode electrode end, and has a potential (low potential region) where H 2 O 2 which is a precursor of hydroxy radical (.OH) is likely to exist. Can be reduced.

しかも、固体高分子電解質膜１８の外周端部１８ｃは、アノード電極２０側に湾曲形成されている。従って、図４に示すように、電位が０．２Ｖ以下になる領域（Ｈ２Ｏ２が急増する領域）Ｓは、カソード電極２２の外周端部から距離ｌだけ外方に離間している。これにより、簡単な構成で、カソード電極２２及び固体高分子電解質膜１８等の劣化を良好に抑制することが可能になるという効果が得られる。このため、燃料電池１２の長寿命化が容易に図られる。 In addition, the outer peripheral end 18c of the solid polymer electrolyte membrane 18 is curvedly formed on the anode electrode 20 side. Therefore, as shown in FIG. 4, the region S in which the potential is 0.2 V or less (the region where H 2 O 2 rapidly increases) S is spaced outward from the outer peripheral end of the cathode electrode 22 by a distance l. Thereby, it is possible to obtain an effect that the deterioration of the cathode electrode 22 and the solid polymer electrolyte membrane 18 and the like can be satisfactorily suppressed with a simple configuration. For this reason, the lifetime of the fuel cell 12 can be easily extended.

１０…電解質膜・電極構造体 １２…燃料電池
１４、１６…セパレータ １８…固体高分子電解質膜
１８ｃ…外周端部 ２０…アノード電極
２２…カソード電極 ２４…樹脂製枠部材
３０ａ…酸化剤ガス入口連通孔 ３０ｂ…酸化剤ガス出口連通孔
３２ａ…冷却媒体入口連通孔 ３２ｂ…冷却媒体出口連通孔
３４ａ…燃料ガス入口連通孔 ３４ｂ…燃料ガス出口連通孔
３６…酸化剤ガス流路 ３８…燃料ガス流路
４０…冷却媒体流路 ４２、４４…シール部材
５０…段差ＭＥＡ ５２…射出成形機
５４、５６…型部材 ５８…キャビティ
６０…射出口 DESCRIPTION OF SYMBOLS 10 ... Electrolyte membrane electrode assembly 12 ... Fuel cell 14, 16 ... Separator 18 ... Solid polymer electrolyte membrane 18c ... Outer peripheral edge part 20 ... Anode electrode 22 ... Cathode electrode 24 ... Resin frame member 30a ... Oxidant gas inlet communication Hole 30b ... Oxidant gas outlet communication hole 32a ... Cooling medium inlet communication hole 32b ... Cooling medium outlet communication hole 34a ... Fuel gas inlet communication hole 34b ... Fuel gas outlet communication hole 36 ... Oxidant gas flow path 38 ... Fuel gas flow path 40 ... Cooling medium flow path 42, 44 ... Seal member 50 ... Step MEA 52 ... Injection molding machine 54, 56 ... Mold member 58 ... Cavity 60 ... Injection port

Claims (1)

電解質膜の両側にそれぞれアノード電極及びカソード電極が設けられ、前記カソード電極の外周端部は、前記アノード電極の外周端部よりも外側に突出するとともに、前記電解質膜の外周を周回して樹脂製枠部材が設けられる固体電解質型燃料電池用電解質膜・電極構造体であって、
前記電解質膜の外周端部は、前記カソード電極の外周端部よりも外側に突出するとともに、
前記アノード電極側に湾曲形成されることを特徴とする固体電解質型燃料電池用電解質膜・電極構造体。 An anode electrode and a cathode electrode are respectively provided on both sides of the electrolyte membrane, and the outer peripheral end portion of the cathode electrode protrudes outward from the outer peripheral end portion of the anode electrode, and circulates around the outer periphery of the electrolyte membrane. An electrolyte membrane / electrode structure for a solid oxide fuel cell provided with a frame member,
The outer peripheral end of the electrolyte membrane protrudes outside the outer peripheral end of the cathode electrode,
An electrolyte membrane / electrode structure for a solid oxide fuel cell, wherein the electrolyte membrane / electrode structure is curved on the anode electrode side.
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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9012105B2 (en) 2012-07-03 2015-04-21 Honda Motor Co., Ltd. Membrane electrode assembly for fuel cell
DE102015010419A1 (en) * 2015-08-11 2017-02-16 Daimler Ag Fuel cell, frame for a framed membrane electrode assembly and framed membrane electrode assembly
US9761898B2 (en) 2010-09-16 2017-09-12 Toyota Jidosha Kabushiki Kaisha Membrane electrode assembly, fuel cell using the same and manufacturing method of membrane electrode assembly
RU2679898C1 (en) * 2017-04-17 2019-02-14 Тойота Дзидося Кабусики Кайся Fuel element
CN110336062A (en) * 2019-08-11 2019-10-15 河南豫氢动力有限公司 A kind of fuel cell membrane electrode equipment for cooling die
US11047962B2 (en) * 2014-07-09 2021-06-29 Sony Depthsensing Solutions Sa/Nv Method for binning time-of-flight data

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9761898B2 (en) 2010-09-16 2017-09-12 Toyota Jidosha Kabushiki Kaisha Membrane electrode assembly, fuel cell using the same and manufacturing method of membrane electrode assembly
US9012105B2 (en) 2012-07-03 2015-04-21 Honda Motor Co., Ltd. Membrane electrode assembly for fuel cell
US11047962B2 (en) * 2014-07-09 2021-06-29 Sony Depthsensing Solutions Sa/Nv Method for binning time-of-flight data
DE102015010419A1 (en) * 2015-08-11 2017-02-16 Daimler Ag Fuel cell, frame for a framed membrane electrode assembly and framed membrane electrode assembly
RU2679898C1 (en) * 2017-04-17 2019-02-14 Тойота Дзидося Кабусики Кайся Fuel element
CN110336062A (en) * 2019-08-11 2019-10-15 河南豫氢动力有限公司 A kind of fuel cell membrane electrode equipment for cooling die
CN110336062B (en) * 2019-08-11 2024-03-08 河南豫氢动力有限公司 Die cooling device for fuel cell membrane electrode

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