JP2003142110A - Electrode for fuel cell and fuel cell - Google Patents
Electrode for fuel cell and fuel cellInfo
- Publication number
- JP2003142110A JP2003142110A JP2001333990A JP2001333990A JP2003142110A JP 2003142110 A JP2003142110 A JP 2003142110A JP 2001333990 A JP2001333990 A JP 2001333990A JP 2001333990 A JP2001333990 A JP 2001333990A JP 2003142110 A JP2003142110 A JP 2003142110A
- Authority
- JP
- Japan
- Prior art keywords
- gas
- diffusion layer
- gas diffusion
- fuel cell
- separator
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- 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
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、燃料として純水
素、あるいはメタノールまたは化石燃料からの改質水
素、もしくはメタノール、エタノール、ジメチルエーテ
ルなどの液体燃料を直接用い、空気や酸素を酸化剤とす
る燃料電池に関するものであり、とくに固体高分子を電
解質に用いた燃料電池に関ものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention directly uses pure hydrogen as fuel, reformed hydrogen from methanol or fossil fuel, or liquid fuel such as methanol, ethanol or dimethyl ether, and uses air or oxygen as an oxidant. The present invention relates to a battery, particularly to a fuel cell using a solid polymer as an electrolyte.
【０００２】[0002]
【従来の技術】一般的に高分子電解質形燃料電池の電極
は、高分子電解質を中心としてその外側両面に触媒層を
持ち、さらにその触媒層の外面にガス拡散層を形成す
る。ガス拡散層は、主に次の三つの機能を持つ。その第
一はガス拡散層のさらに外面に形成したガス流路から、
触媒層中の触媒へ均一に燃料ガスもしくは酸化剤ガスな
どの反応ガスを供給するために反応ガスを拡散する機能
である。第二は、触媒層で反応により生成した水を速や
かにガス流路に排出する機能である。第三は、反応に必
要もしくは生成される電子を導電する機能である。2. Description of the Related Art Generally, an electrode of a polymer electrolyte fuel cell has a catalyst layer on both outer sides of the polymer electrolyte, and a gas diffusion layer is formed on the outer surface of the catalyst layer. The gas diffusion layer mainly has the following three functions. The first is from the gas flow path formed on the outer surface of the gas diffusion layer,
It has a function of diffusing the reaction gas in order to uniformly supply the reaction gas such as the fuel gas or the oxidant gas to the catalyst in the catalyst layer. The second is the function of promptly discharging the water generated by the reaction in the catalyst layer to the gas flow path. The third is the function of conducting electrons necessary or generated for the reaction.
【０００３】従って、それぞれ高い反応ガス透過性と水
排出透過性、電子導電性が必要となる。従来の一般的な
技術として、ガス透過能は、ガス拡散層を多孔質構造と
すること。水排出透過能は、フッ素樹脂で代表とされる
撥水性の高分子などを層中に分散し水の詰まり（フラッ
ディング）を抑制すること。電子導電性は、カーボン繊
維や金属繊維、炭素微粉末などの電子導電性材料でガス
拡散層を構成することが行われてきた。Therefore, high reaction gas permeability, water discharge permeability and electronic conductivity are required respectively. As a conventional general technique, for gas permeability, the gas diffusion layer has a porous structure. Water discharge permeability is to control water clogging (flooding) by dispersing water-repellent polymers such as fluororesin in the layer. For electronic conductivity, it has been practiced to form a gas diffusion layer with an electronic conductive material such as carbon fiber, metal fiber, or carbon fine powder.
【０００４】[0004]
【発明が解決しようとする課題】上記の水排出透過能を
向上させるための種々の取り組みは、それぞれ相反する
効果を示す。たとえば、水排出透過能を高めるために、
フッ素樹脂で代表される撥水性高分子などを層中に添加
させた場合、ガス透過能や電子導電性が低下する。そこ
で、ガス拡散層を単一の構成にするのではなく、例えば
炭素繊維により形成された層と炭素微粉末と撥水性高分
子とで形成された層を組み合わせて、上記相反する機能
をうまく両立させる取り組みが種々なされている。The various approaches for improving the water discharge permeability described above show mutually contradictory effects. For example, to increase water discharge permeability,
When a water-repellent polymer typified by a fluororesin is added to the layer, gas permeability and electronic conductivity decrease. Therefore, instead of forming a single gas diffusion layer, for example, a layer formed of carbon fibers and a layer formed of carbon fine powder and a water-repellent polymer are combined to successfully achieve the above-mentioned contradictory functions. There are various efforts to be made.
【０００５】上記撥水性高分子の使用方法として、例え
ば、最も一般的な代表例として特開平０６−２０３８５
１号や０７−１３０３７３号、０８−１０６９１５号、
０９−２５９８９３号公報に開示されているように、ポ
リテトラフルオロエチレン（以下ＰＴＦＥと略。）また
はテトラフルオロエチレンとヘキサフルオロプロピレン
共重合体（以下ＦＥＰ略。）のディスパージョンにガス
拡散層基材であるカーボンペーパーを含浸処理する方法
や、特開平０７−２２０７３４号や０４−６７５７１
号、０３−２０８２６０号、０３−２０８２６１号、０
３−２０８２６２号、０６−４４９８４号公報に開示さ
れているように、ＰＴＦＥを添加した炭素微粉末の層を
形成する方法が開示されている。As a method of using the water-repellent polymer, for example, as the most general representative example, Japanese Patent Laid-Open No. 06-20385.
No. 1 or 07-130373, 08-106915,
As disclosed in Japanese Unexamined Patent Publication No. 09-259893, a gas diffusion layer substrate is provided in a dispersion of polytetrafluoroethylene (hereinafter abbreviated as PTFE) or tetrafluoroethylene and a hexafluoropropylene copolymer (hereinafter abbreviated as FEP). And a method of impregnating carbon paper, which is described in JP-A-07-220734 and 04-67571.
No. 03-208260, 03-208261, 0
As disclosed in 3-208262 and 06-44984, a method for forming a layer of carbon fine powder added with PTFE is disclosed.
【０００６】これらが示すように、カーボンペーパーを
無作意に撥水性高分子溶液に含浸・乾燥処理する方法で
は、撥水性高分子は三次元構造を持つ多孔質基材の繊維
の配列に従い塗着されてしまう。このため、ガス拡散層
中での撥水量を部位毎に制御することが困難となり、ガ
ス拡散層基材の多孔度分布に反比例し、空隙の大きい部
位には撥水材が付着せずに、空隙の小さい部位には撥水
材が集まり易い傾向があった。さらに、ガス拡散層基材
表面に撥水材が多く付き、ガス拡散層基材内部へ水の閉
じ込みが生じ、行き場の無くなった水によりフラッディ
ングを引き起こし、放電特性や信頼性の低下を引き起こ
していた。As described above, in the method of randomly impregnating the carbon paper in the water-repellent polymer solution and drying the carbon paper, the water-repellent polymer is applied according to the arrangement of the fibers of the porous substrate having a three-dimensional structure. It will be worn. For this reason, it becomes difficult to control the amount of water repellency in the gas diffusion layer on a site-by-site basis, and it is inversely proportional to the porosity distribution of the gas diffusion layer substrate, and the water-repellent material does not adhere to the site with large voids, The water-repellent material tended to collect easily in the areas with small voids. Furthermore, the surface of the gas diffusion layer base material has a large amount of water-repellent material, which causes water to be confined inside the gas diffusion layer base material, causing flooding due to the water having nowhere to go, and causing deterioration of discharge characteristics and reliability. It was
【０００７】これらは、ガス拡散層中のガス透過流路と
水分透過流路が同一箇所なため、余剰水を効率良く排出
できずにフラディングを招き、ガス拡散性を阻害し結果
として、放電特性や信頼性の低下を引き起こしていた。Since the gas permeable channel and the moisture permeable channel in the gas diffusion layer are at the same location, excess water cannot be efficiently discharged, leading to flooding, which impedes gas diffusivity and results in discharge. It caused deterioration of characteristics and reliability.
【０００８】また、例えば特開昭６１−１３８４６３
号、特開昭６１−２５６５６８号、特開平０９−０５０
８１７号、特開平１１−２８８０８６号公報に開示され
ているように、セパレータのガス流路の溝幅や溝深さを
最適化することで、ガス拡散性の電極内での均一化に取
り組むことが図られている。特開平７−１９２７３９号
公報に開示されているように、ガス流路の凸部に切り込
みを入れガス拡散性を確保するなど、セパレータ側から
のアプローチも盛んに行われている。しかし、セパレー
タのガス流路を最適化するには加工が複雑になり、ガス
の分配性を最適化すればするほど製造コストが高くなる
という課題がある。[0008] Further, for example, JP-A-61-138463.
JP-A-61-256568, JP-A-09-050
As disclosed in JP-A No. 817 and JP-A No. 11-288086, it is attempted to make the gas diffusive electrode uniform within the electrode by optimizing the groove width and groove depth of the gas passage of the separator. Is being pursued. As disclosed in Japanese Unexamined Patent Publication No. 7-192739, approaches from the separator side have been actively made, such as making a cut in the convex portion of the gas flow passage to ensure gas diffusibility. However, there is a problem that the processing becomes complicated to optimize the gas flow path of the separator, and the manufacturing cost increases as the gas distributability is optimized.
【０００９】このように、ガス透過性および余剰水透過
性を制御するため様々な構成が考えられているが、ガス
透過性および水透過性を制御するためにはガス拡散層基
材の基本構成を最適化することが必要であり、これを助
ける働きとしてセパレータの流路設計が必要と考えられ
る。As described above, various configurations have been considered for controlling the gas permeability and the surplus water permeability, but in order to control the gas permeability and the water permeability, the basic configuration of the gas diffusion layer base material is used. Is required, and it is considered that the flow path design of the separator is necessary to help this.
【００１０】本発明はこれら上記従来の課題を解決する
もので、ガス拡散層内でのガス拡散性および余剰水透過
性を確保するため、高分子電解質とこれを挟持してなる
触媒層とさらにこれを挟持してなるガス拡散層とさらに
これを挟持してなる連続した凹凸によるガス流路をもつ
セパレータとからなる燃料電池において、前記ガス拡散
層が前記セパレータと接する面内で、集電部分とガス透
過および水蒸気透過部分と水分透過部分に分かれて構成
させるものであり、特に高加湿状態で、かつ、高電流密
度領域での発電における放電性能および信頼性の高い電
極および燃料電池を提供することを目的とするものであ
る。The present invention solves the above-mentioned conventional problems. To secure gas diffusivity and excess water permeability in the gas diffusion layer, a polymer electrolyte and a catalyst layer sandwiching the polymer electrolyte are further provided. In a fuel cell comprising a gas diffusion layer sandwiching the gas diffusion layer and a separator having a gas flow path with continuous irregularities sandwiching the gas diffusion layer, in a plane where the gas diffusion layer contacts the separator, a current collecting portion is formed. And a gas permeation / water vapor permeation part and a water permeation part, which are configured separately, and particularly provide an electrode and a fuel cell with high discharge performance and high reliability in power generation in a high current density region in a high humidification state. That is the purpose.
【００１１】[0011]
【課題を解決するための手段】上記課題を解決するため
に本発明の燃料電池用電極は、水素イオン伝導性高分子
電解質膜と、前記水素イオン伝導性高分子電解質膜を挟
んだ位置に配置した一対の電極と、前記電極の一方に燃
料ガスを供給排出し他方に酸化剤ガスを供給排出するガ
ス流路を有する一対のセパレータとを具備した燃料電池
に用いる電極であって、前記電極は前記水素イオン伝導
性高分子電解質膜を挟持した触媒層と、前記触媒層を挟
持したガス拡散層とを有し、前記ガス拡散層は前記セパ
レータと接する面内で、集電部分と、ガスおよび水蒸気
透過部分と、水分透過部分とに分けて構成したことを特
徴とする。In order to solve the above problems, a fuel cell electrode of the present invention is arranged at a position sandwiching a hydrogen ion conductive polymer electrolyte membrane and the hydrogen ion conductive polymer electrolyte membrane. An electrode used for a fuel cell comprising a pair of electrodes, and a pair of separators having a gas flow path for supplying and discharging a fuel gas to one of the electrodes and supplying and discharging an oxidant gas to the other, wherein the electrode is It has a catalyst layer sandwiching the hydrogen ion conductive polymer electrolyte membrane, and a gas diffusion layer sandwiching the catalyst layer, the gas diffusion layer in a plane in contact with the separator, a current collecting portion, a gas and It is characterized in that it is configured by being divided into a water vapor permeable portion and a moisture permeable portion.
【００１２】このとき、ガス拡散層を、炭素繊維が密な
部分と粗な部分とで構成したことが有効である。At this time, it is effective that the gas diffusion layer is composed of a portion where the carbon fibers are dense and a portion where the carbon fibers are rough.
【００１３】また、セパレータのガス流路を前記セパレ
ータの凹凸で形成し、ガス拡散層の面内で前記セパレー
タの凸部による圧力を受けない箇所を形成したことを特
徴とする。Further, the gas passage of the separator is formed by the unevenness of the separator, and a portion is formed in the surface of the gas diffusion layer which is not subjected to pressure by the convex portion of the separator.
【００１４】このとき、ガス拡散層の面内でセパレータ
の凸部による圧力を受けない箇所を一定の間隔で複数個
形成したことが望ましい。At this time, it is desirable to form a plurality of locations in the plane of the gas diffusion layer that are not subjected to the pressure of the convex portions of the separator at regular intervals.
【００１５】さらに、ガス拡散層の面内でセパレータの
凸部による圧力を受けない箇所は、隣り合う間隔を中心
値で０．３ｍｍ以上１０ｍｍ以下としたことが望まし
い。Further, it is desirable that, in a portion of the surface of the gas diffusion layer which is not subjected to the pressure of the convex portion of the separator, the distance between adjacent portions is 0.3 mm or more and 10 mm or less in the center value.
【００１６】また、ガス拡散層のセパレータの凸部によ
り締め付けられる部分の締結圧力が、凸部面積換算で
０．１ｋｇ／ｃｍ2以上１５ｋｇ／ｃｍ2以下であること
が望ましい。Further, it is desirable that the fastening pressure of the portion of the gas diffusion layer which is fastened by the convex portion of the separator is 0.1 kg / cm 2 or more and 15 kg / cm 2 or less in terms of the convex portion area.
【００１７】[0017]
【発明の実施の形態】上記課題を解決するために本発明
の燃料電池は、燃料電池の電極を構成しているガス拡散
層に下記の構成を持たせるものである。BEST MODE FOR CARRYING OUT THE INVENTION In order to solve the above problems, the fuel cell of the present invention is one in which the gas diffusion layer forming the electrode of the fuel cell has the following constitution.
【００１８】高分子電解質とこれを挟持してなる触媒層
とさらにこれを挟持してなるガス拡散層とさらにこれを
挟持してなる連続した凹凸によるガス流路をもつセパレ
ータとからなる燃料電池において、前記ガス拡散層が前
記セパレータと接する面内で、集電部分とガス透過およ
び水蒸気透過部分と水分透過部分に分かれて構成させる
ことを特徴とするものである。In a fuel cell comprising a polymer electrolyte, a catalyst layer sandwiching the polymer electrolyte, a gas diffusion layer sandwiching the polymer electrolyte layer, and a separator having a gas channel with continuous irregularities sandwiching the catalyst layer. In the surface where the gas diffusion layer contacts the separator, the gas diffusion layer is divided into a current collecting portion and a gas permeable portion, and a water vapor permeable portion and a moisture permeable portion.
【００１９】この構成によって、電極内でのフラッディ
ングを抑制し、ガス拡散性および水蒸気透過性を確保す
ることが可能となり放電性能および信頼性の高い電極お
よび燃料電池を提供することができる。With this structure, it is possible to suppress flooding in the electrode and ensure gas diffusivity and water vapor permeability, and it is possible to provide an electrode and a fuel cell having high discharge performance and reliability.
【００２０】本発明は、高分子電解質とこれを挟持して
なる触媒層とさらにこれを挟持してなるガス拡散層とさ
らにこれを挟持してなる連続した凹凸によるガス流路を
もつセパレータとからなる燃料電池において、前記ガス
拡散層が前記セパレータと接する面内で、集電部分とガ
ス透過部分と水分透過部分に分かれて構成されているこ
とを特徴とするガス拡散層であり、それぞれガス拡散層
に求められる必要な目的を区分することでガス拡散性お
よび水移動路を確保し、放電性能および信頼性の高い電
極を提供するという作用を有する。The present invention comprises a polymer electrolyte, a catalyst layer sandwiching the polymer electrolyte, a gas diffusion layer sandwiching the polymer electrolyte layer, and a separator having a gas passage with continuous irregularities sandwiching the polymer electrolyte layer. In the fuel cell, the gas diffusion layer is characterized in that the gas diffusion layer is divided into a current collecting portion, a gas permeable portion, and a moisture permeable portion in the surface in contact with the separator, and the gas diffusion layers are respectively formed. By dividing the necessary purpose required for the layer, it has an effect of ensuring gas diffusibility and a water transfer path, and providing an electrode having high discharge performance and reliability.
【００２１】また、高分子電解質とこれを挟持してなる
触媒層とさらにこれを挟持してなるガス拡散層とさらに
これを挟持してなる連続した凹凸によるガス流路をもつ
セパレータとからなる燃料電池において、前記ガス拡散
層を構成する炭素繊維が密な部分と粗な部分で構成さ
れ、かつ、前記ガス拡散層が前記セパレータと接する面
内で、集電部分とガス透過部分と水分透過部分に分かれ
て構成されていることを特徴とするガス拡散層であり、
炭素繊維の密な部分では電子伝導を行い、炭素繊維の粗
な部分でガス拡散性および水の移動路を確保すること
で、放電性能および信頼性の高い電極を提供するという
作用を有する。Further, the fuel is composed of a polymer electrolyte, a catalyst layer sandwiching the polymer electrolyte, a gas diffusion layer sandwiching the polymer electrolyte, and a separator having a continuous gas flow path with irregularities sandwiching the gas diffusion layer. In the battery, the carbon fibers constituting the gas diffusion layer are composed of a dense portion and a rough portion, and in the surface where the gas diffusion layer is in contact with the separator, a current collecting portion, a gas permeable portion and a moisture permeable portion. It is a gas diffusion layer characterized by being divided into
Electrons are conducted in the dense portion of the carbon fiber, and the rough portion of the carbon fiber secures the gas diffusivity and the movement path of water, so that it has an effect of providing an electrode having high discharge performance and reliability.
【００２２】また、高分子電解質とこれを挟持してなる
触媒層とさらにこれを挟持してなるガス拡散層とさらに
これを挟持してなる連続した凹凸によるガス流路をもつ
セパレータとからなる燃料電池において、前記ガス拡散
層が前記セパレータと接する面内で、集電部分とガス透
過部分と水分透過部分に分かれて構成され、かつ、前記
ガス拡散層の面内で前記セパレータの凸部によって締め
付けられる圧力が掛かっていない箇所をもつことを特徴
とする燃料電池であり、セパレータ上に形成されたガス
流路のための凸部で締め付けられた部分で十分な電子伝
導性を確保し、圧力の掛かっていない部分で余剰水移動
のための流路を確保できることにより、放電性能および
信頼性の高い燃料電池用電極を提供するという作用を有
する。Further, a fuel comprising a polymer electrolyte, a catalyst layer sandwiching the polymer electrolyte, a gas diffusion layer sandwiching the catalyst layer, and a separator having a gas channel with continuous irregularities sandwiching the gas diffusion layer. In the battery, in the surface where the gas diffusion layer is in contact with the separator, the gas diffusion layer is divided into a current collecting portion, a gas permeable portion, and a moisture permeable portion, and tightened by the convex portion of the separator in the surface of the gas diffusion layer. The fuel cell is characterized by having a portion where no pressure is applied, ensuring sufficient electronic conductivity in the portion clamped by the convex portion for the gas flow path formed on the separator, Since it is possible to secure a flow path for moving excess water in the non-hanging portion, there is an effect of providing a fuel cell electrode having high discharge performance and reliability.
【００２３】また、高分子電解質とこれを挟持してなる
触媒層とさらにこれを挟持してなるガス拡散層とさらに
これを挟持してなる連続した凹凸によるガス流路をもつ
セパレータとからなる燃料電池において、前記ガス拡散
層が前記セパレータと接する面内で、集電部分とガス透
過および水蒸気透過部分と水分透過部分に分かれて構成
され、かつ、前記ガス拡散層の面内で前記セパレータの
凸部によって締め付けられる箇所と締め付けられない箇
所が一定の間隔で存在していることを特徴とする燃料電
池であり、電極内に集電部分と水移動流路とガス拡散流
路が均一に確保されているため、放電性能および信頼性
の高い燃料電池用電極を提供するという作用を有する。Further, a fuel comprising a polymer electrolyte, a catalyst layer sandwiching the polymer electrolyte, a gas diffusion layer sandwiching the catalyst layer, and a separator having a gas passage with continuous irregularities sandwiching the polymer electrolyte layer. In the battery, in the surface where the gas diffusion layer is in contact with the separator, the gas diffusion layer is divided into a current collecting portion, a gas permeation portion, a water vapor permeation portion and a moisture permeation portion, and the protrusion of the separator is in the plane of the gas diffusion layer. The fuel cell is characterized in that there is a fixed interval between the part that is tightened by the part and the part that is not tightened, and the current collecting part, the water transfer flow path, and the gas diffusion flow path are evenly secured in the electrode. Therefore, it has an effect of providing a fuel cell electrode having high discharge performance and high reliability.
【００２４】また、高分子電解質とこれを挟持してなる
触媒層とさらにこれを挟持してなるガス拡散層とさらに
これを挟持してなる連続した凹凸によるガス流路をもつ
セパレータとからなる燃料電池において、前記ガス拡散
層が前記セパレータと接する面内で、集電部分とガス透
過および水蒸気透過部分と水分透過部分に分かれて構成
され、かつ、前記ガス拡散層の面内で前記セパレータの
凸部によって締め付けられる箇所の隣り合う間隔が中心
値で０．５ｍｍ以上１０ｍｍ以下の間隔で存在している
ことを特徴とする燃料電池であり、電極内に集電部分と
水移動流路とガス拡散流路が均一に確保されていると共
に、集電部分と水移動流路とガス拡散流路が緻密に配置
されていることにより、電流密度の集中や、余剰水の集
中がない放電性能および信頼性の高い燃料電池用電極を
提供するという作用を有する。A fuel comprising a polymer electrolyte, a catalyst layer sandwiching the polymer electrolyte, a gas diffusion layer sandwiching the polymer electrolyte, and a separator having a gas passage with continuous irregularities sandwiching the polymer electrolyte. In the battery, in the surface where the gas diffusion layer is in contact with the separator, the gas diffusion layer is divided into a current collecting portion, a gas permeation portion, a water vapor permeation portion and a moisture permeation portion, and the protrusion of the separator is in the plane of the gas diffusion layer. The fuel cell is characterized in that the intervals between the parts tightened by the parts are present at a center value of 0.5 mm or more and 10 mm or less, and a current collecting portion, a water transfer flow path, and gas diffusion are provided in the electrode. Discharge performance without current concentration and excess water concentration due to the uniform distribution of the flow passage and the precise arrangement of the current collector, water movement flow passage, and gas diffusion flow passage. It has the effect of providing a pre-reliable fuel cell electrode.
【００２５】また、高分子電解質とこれを挟持してなる
触媒層とさらにこれを挟持してなるガス拡散層とさらに
これを挟持してなる連続した凹凸によるガス流路をもつ
セパレータとからなる燃料電池において、前記ガス拡散
層が前記セパレータと接する面内で、集電部分とガス透
過および水蒸気透過部分と水分透過部分に分かれて構成
され、かつ、前記ガス拡散層が前記セパレータの凸部に
よって締め付けられる集電部分の締結圧力が凸部面積換
算で０．１ｋｇ／ｃｍ２以上１５ｋｇ／ｃｍ２以下であ
ることを特徴とするガス拡散層であり、セパレータ上に
形成されたガス流路のための凸部で締め付けられた部分
で十分な電子伝導性を確保しながら、締め付け圧の増加
に伴なう粗密度の差の低下および内部短絡を防止するこ
とが可能となり、放電性能および信頼性の高い電極を提
供するという作用を有する。Further, a fuel comprising a polymer electrolyte, a catalyst layer sandwiching the polymer electrolyte, a gas diffusion layer sandwiching the polymer electrolyte, and a separator having a gas passage with continuous irregularities sandwiching the polymer electrolyte In the battery, in the surface where the gas diffusion layer is in contact with the separator, the gas diffusion layer is configured to be divided into a current collecting portion, a gas permeable portion, a water vapor permeable portion and a moisture permeable portion, and the gas diffusion layer is fastened by a convex portion of the separator. The gas diffusion layer is characterized in that the fastening pressure of the current collecting portion is 0.1 kg / cm 2 or more and 15 kg / cm 2 or less in terms of the area of the convex portion, and the convex portion for the gas flow path formed on the separator is formed. While ensuring sufficient electronic conductivity in the part tightened with, it becomes possible to prevent the decrease in the difference in coarse density and the internal short circuit due to the increase in tightening pressure, It has the effect of providing conductive performance and reliable electrodes.
【００２６】以下、本発明の実施の形態を具体的に説明
する。The embodiments of the present invention will be specifically described below.
【００２７】図１に示すとおり、例えば、高分子電解質
膜１の外面に２Ａ、２Ｂで示される触媒層が挟持され、
さらにその外面に３Ａ、３Ｂで示されるガス拡散層が挟
持されることにより燃料電池の基本が構成されている。
電極反応は２Ａおよび２Ｂの触媒表面で起こる。アノー
ド反応ガスは５Ａ、５Ｂで示されるセパレータに形成さ
れた連続した凹凸部の反応ガス供給孔４Ａから３Ａを通
り２Ａへ、カソード反応ガスは４Ｂから３Ｂを通り２Ｂ
へ供給される。As shown in FIG. 1, for example, the catalyst layers 2A and 2B are sandwiched between the outer surfaces of the polymer electrolyte membrane 1,
Further, the basics of the fuel cell are configured by sandwiching the gas diffusion layers 3A and 3B on the outer surface thereof.
Electrode reactions occur on the catalytic surfaces of 2A and 2B. The anode reaction gas passes through the reaction gas supply holes 4A to 3A of the continuous uneven portion formed on the separator 5A and 5B to 2A, and the cathode reaction gas passes from 4B to 3B to 2B.
Is supplied to.
【００２８】アノード触媒層２ＡではＨ2→２Ｈ+＋２ｅ
-の反応が起こり、カソード触媒層２Ｂでは１／２Ｏ2＋
２Ｈ+＋２ｅ-→Ｈ2０の反応が起こり、全体としてＨ2＋
１／２Ｏ2→Ｈ2Ｏ＋Ｑとなる。この反応により起電力が
得られ、この電気エネルギーにより発電がなされるが、
同時に水の生成がカソード触媒層２Ｂで起こる。また、
起電反応の際、アノード触媒層２Ａで生じたＨ+は高分
子電解質膜１中を移動しカソード触媒層２Ｂへ至る。こ
の際１個のＨ+イオンが移動する際、５〜２０個のＨ2Ｏ
分子を同伴して移動する。高分子電解質膜は十分な水が
存在し初めてＨ+イオンの高い導電性を発揮する性質が
ある。In the anode catalyst layer 2A, H 2 → 2H + + 2e
- the following reaction occurs in the cathode catalyst layer 2B 1 / 2O 2 +
2H + + 2e − → H 2 0 reaction occurs, and H 2 + as a whole
1 / 2O 2 → H 2 O + Q. An electromotive force is obtained by this reaction, and electric power is generated by this electric energy.
At the same time, water is produced in the cathode catalyst layer 2B. Also,
During the electromotive reaction, H + generated in the anode catalyst layer 2A moves in the polymer electrolyte membrane 1 and reaches the cathode catalyst layer 2B. At this time, when one H + ion moves, 5 to 20 H 2 O
Move with molecules. The polymer electrolyte membrane has the property of exhibiting high conductivity of H + ions only when sufficient water is present.
【００２９】そのため、高分子電解質膜中を移動するＨ
+イオンに同伴して移動するため不足する水を常に供給
する必要があり、この水は反応ガス供給孔を兼ね備えた
４Ａおよび４Ｂから３Ａおよび３Ｃを通り水蒸気として
供給する。また、カソード触媒層内で生成された水のう
ち、高分子電解質膜が必要としない余剰水はガス拡散層
３Ａおよび３Ｂを通り、反応ガス供給孔と余剰ガスおよ
び余剰水排出孔を兼ねた４Ａおよび４Ｂから排出され
る。このため、燃料電池では、水の出入りの多いガス拡
散層のガス拡散性および余剰水の排出流路を確保するこ
とが重要となり、長期信頼性の点からも余剰水を速やか
に排出させる方向で設計する必要がある。Therefore, H moving in the polymer electrolyte membrane
It is necessary to always supply a shortage of water because it moves along with + ions, and this water is supplied as water vapor through 4A and 4B, which also have reaction gas supply holes, through 3A and 3C. In addition, of the water generated in the cathode catalyst layer, excess water not required by the polymer electrolyte membrane passes through the gas diffusion layers 3A and 3B and serves as a reaction gas supply hole and an excess gas and excess water discharge hole 4A. And discharged from 4B. Therefore, in the fuel cell, it is important to secure the gas diffusivity of the gas diffusion layer where much water flows in and out and the discharge channel of the excess water, and from the viewpoint of long-term reliability, it is necessary to promptly discharge the excess water. Need to be designed.
【００３０】ガス拡散層の構成として、従来ガス拡散層
のさらに外面に形成されたガス流路から触媒層中の触媒
へ均一に燃料ガスおよび酸化剤ガスなどの反応ガスを供
給するために反応ガスを拡散する機能と、触媒層で反応
により生成した水を速やかにガス流路に排出する機能
と、さらには、反応に必要もしくは生成される電子を導
電する機能を同時に行っていた部分を、局部的に電子伝
導を行う部分とガスを通す部分と水分を通す部分に区分
し、さらには、緻密で、かつ、均一に配置する。ガス拡
散層基材を構成する炭素繊維が集中している密な部分で
主に電子伝導を行い、逆に粗な部分で主にガス透過を行
い、繊維の無い部分で主に水を排出させる構成とする。
これにより、カソード触媒層中で生成された余剰水はガ
ス拡散層の専用通路を通り排出孔まですみやかに移動す
ることが可能となると共にガス拡散性には影響を及ぼす
ことは無い。このように、電極中で余剰とされる水は水
移動専用の通路を通ることにより、電極中で水詰まりが
起こらず、フラッディングを招くことが無く、ガス拡散
性の低下をも引き起こすことの無い、放電特性および信
頼性の高い燃料電池を提供することが図れる。As the constitution of the gas diffusion layer, the reaction gas for uniformly supplying the reaction gas such as the fuel gas and the oxidant gas from the gas passage formed on the outer surface of the conventional gas diffusion layer to the catalyst in the catalyst layer. The function of diffusing water, the function of rapidly discharging the water generated by the reaction in the catalyst layer to the gas flow path, and the function of conducting the electrons necessary for the reaction or generated at the same time A portion that electrically conducts electrons, a portion that allows gas to pass therethrough, and a portion that allows moisture to pass therethrough. Further, they are arranged densely and uniformly. Electron conduction is mainly carried out in the dense part where the carbon fibers constituting the gas diffusion layer base material are concentrated, conversely gas is mainly permeated in the rough part, and water is mainly discharged in the part without fibers. The configuration.
As a result, the surplus water generated in the cathode catalyst layer can be quickly moved to the discharge hole through the dedicated passage of the gas diffusion layer, and the gas diffusivity is not affected. As described above, excess water in the electrode passes through the passage dedicated to water movement, so that water clogging does not occur in the electrode, flooding does not occur, and gas diffusivity does not deteriorate. It is possible to provide a fuel cell having high discharge characteristics and high reliability.
【００３１】以上の本発明の方法により作製されたガス
拡散層を用いることによって、放電特性および信頼性の
高い燃料電池を提供することができる。さらに詳しくは
実施例において具体的に説明する。By using the gas diffusion layer produced by the above method of the present invention, it is possible to provide a fuel cell having high discharge characteristics and high reliability. Further details will be specifically described in Examples.
【００３２】[0032]
【実施例】（実施例１）ガス拡散層基材として太さ約１
０μｍのポリアクリルニトリル繊維をより合わせて太さ
約３００μｍにした糸を編んだ布を作製し、次いでこれ
を窒素雰囲気下２０００℃で２４時間加熱し、黒鉛化さ
せカーボンクロスを得た。これを、ダイキン工業製ＦＥ
Ｐディスパージョン（商品名ＮＤ−１）と水が重量比で
１：１０となるように作製したＦＥＰディスパージョン
の希釈溶液に１分間含浸させ、約６０℃で１時間乾燥さ
せた。この上に、アセチレンブラックとＰＴＦＥとが重
量比で３：１になるよう水溶媒の分散液を作製し、ドク
ターブレードを用いて分散液を塗工し撥水層を作製し
た。約６０℃で１時間乾燥させた後、約３８０℃で１５
分焼成した。[Example] (Example 1) About 1 in thickness as a gas diffusion layer base material
A cloth in which 0 μm polyacrylonitrile fibers were twisted together to knit a thread having a thickness of about 300 μm was produced, and then this was heated in a nitrogen atmosphere at 2000 ° C. for 24 hours to be graphitized to obtain a carbon cloth. This is FE made by Daikin Industries
The diluted solution of the FEP dispersion prepared so that the weight ratio of P dispersion (trade name ND-1) to water was 1:10 was impregnated for 1 minute and dried at about 60 ° C. for 1 hour. On this, a dispersion of an aqueous solvent was prepared such that acetylene black and PTFE were in a weight ratio of 3: 1, and the dispersion was applied using a doctor blade to prepare a water repellent layer. After drying at about 60 ℃ for 1 hour, at about 380 ℃ 15
Minutes were fired.
【００３３】この際、出来上がったガス拡散層には面内
に、繊維の折り重なった密な部分と、繊維の折り重なっ
ていない粗な部分と、縦方向の繊維と横方向の繊維が交
差する厚み方向に繊維の無い部分とを作った。この部分
の厚みは繊維の密な部分が約１５０μｍから３００μ
ｍ、繊維の粗な部分が約７μｍから１５０μｍであり、
繊維の折り重なりあう部分が隣り合う間隔は約１ｍｍと
した。At this time, in the finished gas diffusion layer, in-plane dense portions where fibers are folded, rough portions where fibers are not folded, and longitudinal direction and transverse direction fibers intersect in the thickness direction. I made a part with no fiber. The thickness of this part is about 150μm to 300μ in the dense part of the fiber.
m, the coarse portion of the fiber is about 7 μm to 150 μm,
The interval at which the overlapping portions of the fibers were adjacent to each other was about 1 mm.
【００３４】ライオン社の炭素微粉末ケッチェンブラッ
クＥＣ１００重量％上に白金触媒を１００重量％担持し
た触媒を、米国デュポン社製Ｎａｆｉｏｎ膜と同じ高分
子であるパーフルオロスルホン酸樹脂を１００重量％混
合し、成形した触媒層を１６０℃の熱溶着により、米国
デュポン社製Ｎａｆｉｏｎ１１２膜の両面に接合した。
さらにこの両側から上記の通り作製したガス拡散層で撥
水層が触媒層と接するように接合し、これを、連続した
凹凸によるガス流路を持つセパレータで挟み水素―空気
型の燃料電池として単電池Ａを作成した。この際、電極
に掛かる締結圧力は約１０ｋｇ／ｃｍ2とした。100% by weight of a platinum fine powder Ketjen Black EC manufactured by Lion Corp. was mixed with 100% by weight of a platinum catalyst, and 100% by weight of a perfluorosulfonic acid resin, which is the same polymer as the Nafion membrane manufactured by DuPont USA, was used. Then, the formed catalyst layer was bonded to both sides of a Nafion 112 membrane manufactured by DuPont, USA by heat welding at 160 ° C.
Further, the water-repellent layer was joined to the catalyst layer with the gas diffusion layer prepared as described above from both sides, and this was sandwiched between separators having gas channels with continuous irregularities to form a single hydrogen-air fuel cell. Battery A was made. At this time, the fastening pressure applied to the electrodes was set to about 10 kg / cm 2 .
【００３５】（比較例２）ガス拡散層基材として、太さ
約２０μｍのポリアクリルニトリル繊維をより合わせて
太さ約５００μｍにした糸を編んだ布を作製し、次いで
これを窒素雰囲気下２０００℃で２４時間加熱し、黒鉛
化させカーボンクロスを得た。これを、ダイキン工業製
ＦＥＰディスパージョン（商品名ＮＤ−１）と水が重量
比で１：１０となるように作製したＦＥＰディスパージ
ョンの希釈溶液に１分間含浸させ、約６０℃で１時間乾
燥させた。この上に、アセチレンブラックとＰＴＦＥと
が重量比で３：１になるよう水溶媒の分散液を作製し、
ドクターブレードを用いて分散液を塗工し撥水層を作製
した。約６０℃で１時間乾燥させた後、約３８０℃で１
５分焼成した。(Comparative Example 2) As a gas diffusion layer base material, a cloth was prepared in which polyacrylonitrile fibers having a thickness of about 20 μm were twisted together to make a thickness of about 500 μm, and then the cloth was knitted. It was heated at ℃ for 24 hours and graphitized to obtain carbon cloth. This is impregnated with a dilute solution of FEP dispersion (trade name ND-1) manufactured by Daikin Industries, Ltd. and water in a weight ratio of 1:10 for 1 minute, and dried at about 60 ° C. for 1 hour. Let On this, a dispersion of an aqueous solvent was prepared so that the weight ratio of acetylene black and PTFE was 3: 1,
The water repellent layer was produced by applying the dispersion liquid using a doctor blade. After drying at about 60 ℃ for 1 hour, at about 380 ℃ 1
It was baked for 5 minutes.
【００３６】この際、出来上がったガス拡散層には面内
に、繊維の折り重なった密な部分と、繊維の折り重なっ
ていない粗な部分と、縦方向の繊維と横方向の繊維が交
差する厚み方向に繊維の無い部分とを作った。この部分
の厚みは繊維の密な部分が約２５０μｍから５００μ
ｍ、繊維の粗な部分が約１０μｍから２５０μｍであ
り、繊維の折り重なりあう部分が隣り合う間隔は約１１
ｍｍとした。ライオン社の炭素微粉末ケッチェンブラッ
クＥＣ１００重量％上に白金触媒を１００重量％担持し
た触媒をＮａｆｉｏｎ膜と同じ高分子であるパーフルオ
ロスルホン酸樹脂を１００重量％混合し、成形した触媒
層を１６０℃の熱溶着により米国デュポン社製Ｎａｆｉ
ｏｎ１１２膜の両面に接合し、さらにこの両側から上記
の通り作製したガス拡散層で撥水層が触媒層と接するよ
うに接合し、これを、連続した凹凸によるガス流路を持
つセパレータで挟み水素―空気型の燃料電池として単電
池Ｂを作成した。この際、電極に掛かる締結圧力は約１
０ｋｇ／ｃｍ2とした。At this time, in the finished gas diffusion layer, in-plane dense portions where the fibers are folded, rough portions where the fibers are not folded, and the thickness direction where the longitudinal fibers and the transverse fibers intersect I made a part with no fiber. The thickness of this part is about 250μm to 500μ in the dense part of the fiber.
m, the coarse portion of the fiber is about 10 μm to 250 μm, and the interval where the overlapping portions of the fiber are adjacent is about 11
mm. 100% by weight of carbon fine powder Ketjen Black EC manufactured by Lion Corporation was mixed with 100% by weight of a catalyst carrying a platinum catalyst and 100% by weight of a perfluorosulfonic acid resin which is the same polymer as the Nafion membrane, and a molded catalyst layer was formed. Nafi made by DuPont, USA by heat welding at ℃
The on112 membrane is bonded to both sides, and the gas diffusion layers prepared as described above are bonded to both sides of the on112 film so that the water-repellent layer contacts the catalyst layer. -A unit cell B was prepared as an air type fuel cell. At this time, the fastening pressure applied to the electrodes is about 1
It was set to 0 kg / cm 2 .
【００３７】（比較例３）実施例１で作製した電極およ
びセパレータと同様のものを用いて、水素―空気型の燃
料電池として単電池Ｃを作成した。この際、電極に掛か
る締結圧力を約１６ｋｇ／ｃｍ2とした。(Comparative Example 3) A single cell C was prepared as a hydrogen-air type fuel cell using the same electrodes and separators as those prepared in Example 1. At this time, the fastening pressure applied to the electrodes was set to about 16 kg / cm 2 .
【００３８】（比較例４）ガス拡散層基材としては太さ
約１０μｍ、長さ約５μｍに切断したポリアクリルニト
リル繊維を水に分散させ、これを抄紙しシートを作製し
た。次いでこれをエタノールにて濃度４０重量％に希釈
したフェノール樹脂溶液に含浸させ約１００℃で１０分
間乾燥させ樹脂を硬化させた。これを窒素雰囲気下２０
００℃で２４時間加熱し、黒鉛化させカーボンペーパを
得た。さらに、これをダイキン工業製ＦＥＰディスパー
ジョン（商品名ＮＤ−１）と水が重量比で１：１０とな
るように作製したＦＥＰディスパージョンの希釈溶液に
含浸させ、約６０℃で１時間乾燥させた。(Comparative Example 4) As a gas diffusion layer base material, polyacrylonitrile fiber cut to a thickness of about 10 µm and a length of about 5 µm was dispersed in water, and this was paper-made to prepare a sheet. Then, this was impregnated with a phenol resin solution diluted with ethanol to a concentration of 40% by weight and dried at about 100 ° C. for 10 minutes to cure the resin. This in a nitrogen atmosphere 20
It was heated at 00 ° C. for 24 hours and graphitized to obtain carbon paper. Further, this was impregnated with a diluted solution of FEP dispersion (trade name ND-1) manufactured by Daikin Industries and water in a weight ratio of 1:10, and dried at about 60 ° C. for 1 hour. It was
【００３９】この上に、アセチレンブラックとＰＴＦＥ
とが重量比で３：１になるよう水溶媒の分散液を作製
し、ドクターブレードを用いて分散液を塗工し撥水層を
作製した。約６０℃で１時間乾燥させた後、約３８０℃
で１５分焼成した。この際、出来上がったガス拡散層に
は繊維の折り重なった密な部分と繊維の折り重なってい
ない粗な部分を作ることができていたが、面内でこの粗
密部分は不均一に分布していた。On top of this, acetylene black and PTFE
A dispersion of an aqueous solvent was prepared so that the weight ratio of and was 3: 1, and the dispersion was applied using a doctor blade to form a water repellent layer. After drying at about 60 ℃ for 1 hour, then about 380 ℃
It was baked for 15 minutes. At this time, a dense portion where the fibers were folded and a rough portion where the fibers were not folded could be formed in the finished gas diffusion layer, but the dense portions were unevenly distributed in the plane.
【００４０】ライオン社の炭素微粉末ケッチェンブラッ
クＥＣ１００重量％上に白金触媒を１００重量％担持し
た触媒を、Ｎａｆｉｏｎ膜と同じ高分子であるパーフル
オロスルホン酸樹脂を１００重量％混合し、成形した触
媒層を１６０℃の熱溶着により米国デュポン社製Ｎａｆ
ｉｏｎ１１２膜の両面に接合し、さらにこの両側から上
記の通り作製したガス拡散層で撥水層が触媒層と接する
ように接合し、これを、連続した凹凸によるガス流路を
持つセパレータで挟み、水素―空気型の燃料電池として
単電池Ｄを作成した。この際、電極に掛かる締結圧力は
約１０ｋｇ／ｃｍ2とした。A catalyst comprising 100% by weight of a platinum catalyst supported on 100% by weight of carbon fine powder Ketjen Black EC manufactured by Lion Corporation was mixed with 100% by weight of a perfluorosulfonic acid resin, which is the same polymer as the Nafion membrane, and molded. The catalyst layer was heat-welded at 160 ° C. to produce Naf manufactured by DuPont
Bonded to both sides of the ion112 membrane, and further bonded from both sides so that the water-repellent layer is in contact with the catalyst layer by the gas diffusion layers prepared as described above, and sandwiched by a separator having a gas channel with continuous unevenness, A unit cell D was prepared as a hydrogen-air type fuel cell. At this time, the fastening pressure applied to the electrodes was set to about 10 kg / cm 2 .
【００４１】以上のとおり作製した実施例１および比較
例１、２、３の単電池ＡおよびＢ、Ｃ、Ｄの燃料極に純
水素ガスを，空気極に空気をそれぞれ供給し、電池温度
を７５℃、燃料ガス利用率を７０％、空気利用率（以下
Ｕｏと略。）を４０％とした。ガス加湿は燃料ガスを７
０℃、空気を７０℃のバブラーをそれぞれ通して供給
し、水素―空気燃料電池としての単電池の放電試験を行
った。Pure hydrogen gas was supplied to the fuel electrodes of the unit cells A and B, C, and D of Example 1 and Comparative Examples 1, 2, and 3 prepared as described above, and air was supplied to the air electrodes, respectively, to adjust the cell temperature. At 75 ° C, the fuel gas utilization rate was 70%, and the air utilization rate (hereinafter abbreviated as Uo) was 40%. Gas humidification uses fuel gas 7
A discharge test of a single cell as a hydrogen-air fuel cell was performed by supplying 0 ° C. and air through a bubbler at 70 ° C., respectively.
【００４２】図２に，本発明の実施例１の単電池Ａと比
較例１、２、３の単電池Ｂ、Ｃ、Ｄの水素−空気型燃料
電池としての放電特性試験結果を示した。電流密度８０
０ｍＡ／ｃｍ2における単電池電圧で示すと、単電池Ａ
およびＢ、Ｃ、Ｄの電池電圧は、それぞれ６４９ｍＶ、
４３８ｍＶ、４３５ｍＶ、５５１ｍＶであった。また、
電流密度１００ｍＡ／ｃｍ2における単電池電圧で示す
と、単電池ＡおよびＢ、Ｃ、Ｄの電池電圧は、それぞれ
８２７ｍＶ、７３１ｍＶ、８０８ｍＶ、８１３ｍＶであ
った。FIG. 2 shows the discharge characteristic test results of the unit cell A of Example 1 of the present invention and the unit cells B, C, and D of Comparative Examples 1, 2, and 3 as hydrogen-air fuel cells. Current density 80
The unit cell voltage at 0 mA / cm 2 indicates unit cell A
The battery voltages of B, C, and D are 649 mV,
It was 438 mV, 435 mV, and 551 mV. Also,
In terms of the cell voltage at a current density of 100 mA / cm 2, the cell voltages of the cells A, B, C, and D were 827 mV, 731 mV, 808 mV, and 813 mV, respectively.
【００４３】図２から分かるとおり、電流密度が高くな
ればなるほど、放電特性に差が生じている。電流密度が
高くなると、電池からの生成水はそれに比例して多くな
るため、実施例１で作製した集電部分とガス透過部分と
水透過部分に分かれて構成されているガス拡散層をもち
いたものでは、余剰水の滞留がなくフラッディングを引
き起こすことは無く、また、ガス拡散性も確保している
ため、放電性能が良好である。逆に、比較例１で作製し
た集電部分に相当するセパレータからの締結圧を受ける
ガス拡散層の繊維が密な部分の隣り合う間隔が広いもの
では、電子伝導性が十分に行えず内部抵抗を増加させ、
性能が低下している。As can be seen from FIG. 2, the higher the current density, the more the discharge characteristics differ. When the current density increases, the amount of water produced from the battery increases in proportion thereto, so the gas diffusion layer formed in the current collecting part, the gas permeable part, and the water permeable part prepared in Example 1 was used. In this case, there is no excess water retention, no flooding is caused, and the gas diffusibility is secured, so the discharge performance is good. On the contrary, in the case where the gas diffusion layer, which receives the fastening pressure from the separator corresponding to the current collecting portion produced in Comparative Example 1, has a large interval between adjacent dense fiber portions, sufficient electron conductivity cannot be obtained, and the internal resistance is decreased. Increase
Performance is degraded.
【００４４】また、比較例３で作製した集電部分とガス
透過および水蒸気透過部分と水透過部分が明確に分かれ
ていないガス拡散層では、電極内部で水が詰まり、さら
に、これによりガス透過性を阻害し、放電特性の低下を
引き起こしている。さらに、比較例２で作製した燃料電
池は、締め付け圧力が高すぎるため、ガス拡散層内に設
けた繊維の粗密な部分の差が少なくなり、ガス透過性の
ための流路および余剰水排出のための流路の区分が不明
確になり、局部的にフラッディングが生じガス透過性を
阻害したため放電特性の低下を引き起こした。さらに
は、締め付け圧力が高すぎるため内部短絡を起こし、特
に低電流密度領域で性能が低下している。Further, in the gas diffusion layer prepared in Comparative Example 3 in which the current collecting portion and the gas permeable portion and the water vapor permeable portion and the water permeable portion were not clearly separated, water was clogged inside the electrode, which further resulted in gas permeability. Which causes the deterioration of the discharge characteristics. Further, in the fuel cell manufactured in Comparative Example 2, the tightening pressure was too high, so that the difference between the coarse and dense portions of the fibers provided in the gas diffusion layer was reduced, and the flow path for gas permeability and the excess water discharge. Therefore, the division of the flow path became unclear, and the flooding occurred locally, which impeded the gas permeability and deteriorated the discharge characteristics. Furthermore, the tightening pressure is too high, causing an internal short circuit, and the performance is lowered particularly in the low current density region.
【００４５】図３に、本発明の実施例１の単電池Ａと比
較例３の単電池Ｄの水素−空気型燃料電池としての耐久
試験結果を示した。実施例１および比較例３の単電池Ａ
およびＤの燃料極に純水素ガスを，空気極に空気をそれ
ぞれ供給し、電池温度を７５℃、燃料ガス利用率を７０
％、空気利用率（以下Ｕｏと略。）を４０％、電流密度
を０．３Ａ／ｃｍ2とし、ガス加湿は燃料ガスを７０
℃、空気を７０℃のバブラーをそれぞれ通して供給し、
水素―空気燃料電池としての単電池の耐久試験を行っ
た。この結果からも分かる通り、実施例１で作製した集
電部分とガス透過部分と水透過部分に分かれて構成され
ているガス拡散層をもちいたものでは、余剰水の滞留が
なくフラッディングを引き起こすことがなく、また、ガ
ス拡散性も低下させないため、信頼性が良好である。逆
に、比較例３で作製した集電部分とガス透過部分と水透
過部分が明確に分かれていないガス拡散層では、電極内
部で水が詰まり、さらに、ガス拡散層の構成がガス透過
および水蒸気透過部分と水分透過部分に分かれていない
ことによりガス透過性も阻害し、放電特性の低下を引き
起こしている。FIG. 3 shows the durability test results of the unit cell A of Example 1 of the present invention and the unit cell D of Comparative Example 3 as a hydrogen-air fuel cell. Cell A of Example 1 and Comparative Example 3
Pure hydrogen gas is supplied to the fuel electrodes of D and D, and air is supplied to the air electrode, the cell temperature is 75 ° C., and the fuel gas utilization rate is 70.
%, Air utilization rate (hereinafter abbreviated as Uo) 40%, current density 0.3 A / cm 2 , gas humidification 70%
℃, air is supplied through a bubbler at 70 ℃,
A durability test of a single cell as a hydrogen-air fuel cell was performed. As can be seen from these results, in the case of using the gas diffusion layer formed in Example 1, which is divided into the current collecting portion, the gas permeable portion, and the water permeable portion, there is no excess water retention and flooding is caused. In addition, the gas diffusivity is not lowered, and the reliability is good. On the contrary, in the gas diffusion layer prepared in Comparative Example 3 in which the current collecting portion, the gas permeable portion, and the water permeable portion are not clearly separated, water is clogged inside the electrode, and further, the gas diffusion layer has a gas permeable and water vapor composition. Since it is not divided into a permeable portion and a moisture permeable portion, it also impairs gas permeability and causes deterioration of discharge characteristics.
【００４６】このように、本発明の燃料電池のようにガ
ス拡散層がセパレータと接する面内で、集電部分とガス
透過および水蒸気透過部分と水分透過部分に分かれて構
成されていることにより、電極内でのフラッディングを
抑制し、かつ、ガス拡散性および水蒸気透過性を良好に
保つことが可能となり、放電性能および信頼性の高い電
極および燃料電池を提供することが可能となる。As described above, in the fuel cell of the present invention, the gas diffusion layer is divided into the current collecting portion and the gas permeating portion and the water vapor permeating portion and the moisture permeating portion within the surface in contact with the separator. It is possible to suppress flooding in the electrode and maintain good gas diffusivity and water vapor permeability, and it is possible to provide an electrode and a fuel cell having high discharge performance and reliability.
【００４７】燃料電池は通常、複数の単電池を直列また
は並列に接続して用いられる。したがって、単電池での
フラッディングは燃料電池スタックの性能に大きく影響
する。とくに、直列に接続された場合には、最も特性の
低い単電池の限界電流値が燃料電池スタック全体の限界
電流値となってしまうため、最も低い単電池の性能が燃
料電池スタック全体の性能の限界値となる。つまり、単
電池でのフラッディング現象を低減することも今後の重
要な課題となる。The fuel cell is usually used by connecting a plurality of unit cells in series or in parallel. Therefore, flooding in a single cell greatly affects the performance of the fuel cell stack. In particular, when connected in series, the limiting current value of the unit cell with the lowest characteristic becomes the limiting current value of the entire fuel cell stack. It becomes the limit value. In other words, reducing the flooding phenomenon in single cells will also be an important issue in the future.
【００４８】なお、本実施例において燃料の一例とし
て、水素と空気を用いたが、水素は改質水素として炭酸
ガスや窒素、一酸化炭素などの不純物を含む燃料におい
ても同様の結果が得られ、水素の代わりにメタノール、
エタノール、ヂメチルエーテルなどの液体燃料およびそ
の混合物を用いても同様の結果が得られた。また、液体
燃料はあらかじめ蒸発させ、蒸気として供給してもよ
い。Although hydrogen and air were used as an example of the fuel in this embodiment, similar results can be obtained with hydrogen containing reformed hydrogen containing impurities such as carbon dioxide, nitrogen and carbon monoxide. , Methanol instead of hydrogen,
Similar results were obtained using liquid fuels such as ethanol and dimethyl ether and mixtures thereof. Further, the liquid fuel may be vaporized in advance and supplied as vapor.
【００４９】さらに、本発明の燃料電池の構成は、実施
例に示した構成に限定されるものではなく、種種の構成
でも効果があった。Further, the constitution of the fuel cell of the present invention is not limited to the constitution shown in the embodiment, and various constitutions are effective.
【００５０】さらに、本発明の固体高分子型電解質と電
極との接合体を用いて、酸素、オゾン、水素などのガス
発生機やガス精製機および酸素センサ、アルコールセン
サなどの各種ガスセンサへの応用にも効果がある。Further, by using the joined body of the solid polymer electrolyte of the present invention and an electrode, it is applied to a gas generator for oxygen, ozone, hydrogen and the like, a gas purifier and various gas sensors such as an oxygen sensor and an alcohol sensor. Is also effective.
【００５１】[0051]
【発明の効果】以上、実施例の説明から明らかなよう
に、本発明によるガス拡散層および燃料電池の構成を最
適化することによって、触媒層中の触媒に均一に反応ガ
スを供給し、かつ生成された余剰水や生成炭酸ガスを速
やかに排出することが可能となり、高い放電性能と信頼
性を持つ電極および燃料電池を実現することができた。As is apparent from the description of the embodiments above, the reaction gas is uniformly supplied to the catalyst in the catalyst layer by optimizing the configurations of the gas diffusion layer and the fuel cell according to the present invention, and It was possible to quickly discharge the generated excess water and the generated carbon dioxide gas, and it was possible to realize an electrode and a fuel cell with high discharge performance and reliability.
【図１】従来および本発明の燃料電池用電極の断面概略
図FIG. 1 is a schematic cross-sectional view of a fuel cell electrode according to the related art and the present invention.
【図２】本発明の実施例である燃料電池の電圧−電流特
性を示す図FIG. 2 is a diagram showing voltage-current characteristics of a fuel cell that is an embodiment of the present invention.
【図３】本発明の実施例である燃料電池の信頼性を示す
図FIG. 3 is a diagram showing the reliability of a fuel cell according to an embodiment of the present invention.
１ 高分子電解質膜
２Ａ，２Ｂ 触媒層
３Ａ，３Ｂ ガス拡散層
４Ａ，４Ｂ ガス供給孔および余剰水および余剰ガス排
出孔
５Ａ，５Ｂ セパレータ1 Polymer Electrolyte Membranes 2A, 2B Catalyst Layers 3A, 3B Gas Diffusion Layers 4A, 4B Gas Supply Holes and Excess Water and Excess Gas Discharge Holes 5A, 5B Separator
───────────────────────────────────────────────────── フロントページの続き (72)発明者 内田 誠 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 (72)発明者 酒井 修 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 (72)発明者 森田 純司 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 (72)発明者 菅原 靖 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 (72)発明者 武部 安男 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 Ｆターム(参考） 5H018 AA06 AS01 BB01 BB03 BB05 BB06 BB08 BB12 DD05 DD08 EE03 EE06 EE08 EE18 EE19 HH03 HH09 5H026 AA06 BB02 CC03 CX02 CX05 EE05 HH03 HH09 5H027 AA06 KK01 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Makoto Uchida 1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric Sangyo Co., Ltd. (72) Inventor Osamu Sakai 1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric Sangyo Co., Ltd. (72) Inventor Junji Morita 1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric Sangyo Co., Ltd. (72) Inventor Yasushi Sugawara 1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric Sangyo Co., Ltd. (72) Inventor Yasuo Takebe 1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric Sangyo Co., Ltd. F-term (reference) 5H018 AA06 AS01 BB01 BB03 BB05 BB06 BB08 BB12 DD05 DD08 EE03 EE06 EE08 EE18 EE19 HH03 HH09 5H026 AA06 BB02 CC03 CX02 CX05 EE05 HH03 HH09 5H027 AA06 KK01
Claims (7)
記水素イオン伝導性高分子電解質膜を挟んだ位置に配置
した一対の電極と、前記電極の一方に燃料ガスを供給排
出し他方に酸化剤ガスを供給排出するガス流路を有する
一対のセパレータとを具備した燃料電池に用いる電極で
あって、前記電極は前記水素イオン伝導性高分子電解質
膜を挟持した触媒層と、前記触媒層を挟持したガス拡散
層とを有し、前記ガス拡散層は前記セパレータと接する
面内で、集電部分と、ガスおよび水蒸気透過部分と、水
分透過部分とに分けて構成したことを特徴とする燃料電
池用電極。1. A hydrogen ion conductive polymer electrolyte membrane, a pair of electrodes arranged at positions sandwiching the hydrogen ion conductive polymer electrolyte membrane, and a fuel gas is supplied to and discharged from one of the electrodes and oxidized to the other. An electrode used in a fuel cell comprising a pair of separators having a gas flow path for supplying and discharging an agent gas, the electrode comprising a catalyst layer sandwiching the hydrogen ion conductive polymer electrolyte membrane, and the catalyst layer. A fuel having a sandwiched gas diffusion layer, wherein the gas diffusion layer is divided into a current collecting portion, a gas and water vapor permeable portion, and a moisture permeable portion in a plane in contact with the separator. Battery electrode.
な部分とで構成したことを特徴とする請求項１記載の燃
料電池用電極。2. The fuel cell electrode according to claim 1, wherein the gas diffusion layer comprises a carbon fiber dense portion and a coarse portion.
の凹凸で形成し、ガス拡散層の面内で前記セパレータの
凸部による圧力を受けない箇所を形成したことを特徴と
する請求項１または２記載の燃料電池用電極。3. The gas flow path of the separator is formed by unevenness of the separator, and a portion is formed in the plane of the gas diffusion layer that is not subjected to pressure by the convex portion of the separator. The fuel cell electrode described.
よる圧力を受けない箇所を一定の間隔で複数個形成した
ことを特徴とする請求項３記載の燃料電池用電極。4. The fuel cell electrode according to claim 3, wherein a plurality of locations in the plane of the gas diffusion layer that are not subjected to pressure by the protrusions of the separator are formed at regular intervals.
よる圧力を受けない箇所は、隣り合う間隔を中心値で
０．３ｍｍ以上１０ｍｍ以下としたことを特徴とする請
求項４記載の燃料電池用電極。5. The fuel according to claim 4, characterized in that, in a portion of the surface of the gas diffusion layer which is not subjected to the pressure of the convex portion of the separator, the distance between adjacent portions is 0.3 mm or more and 10 mm or less in the center value. Battery electrode.
め付けられる部分の締結圧力が、凸部面積換算で０．１
ｋｇ／ｃｍ2以上１５ｋｇ／ｃｍ2以下であることを特徴
とする請求項３、４または５記載の燃料電池用電極。6. The fastening pressure of the portion of the gas diffusion layer which is fastened by the convex portion of the separator is 0.1 in terms of the convex area.
The fuel cell electrode according to claim 3, 4 or 5, wherein the electrode has a weight of not less than kg / cm 2 and not more than 15 kg / cm 2 .
有する燃料電池。7. A fuel cell having the fuel cell electrode according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001333990A JP3738831B2 (en) | 2001-10-31 | 2001-10-31 | Fuel cell electrode and fuel cell |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001333990A JP3738831B2 (en) | 2001-10-31 | 2001-10-31 | Fuel cell electrode and fuel cell |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2003142110A true JP2003142110A (en) | 2003-05-16 |
| JP3738831B2 JP3738831B2 (en) | 2006-01-25 |
Family
ID=19149185
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001333990A Expired - Fee Related JP3738831B2 (en) | 2001-10-31 | 2001-10-31 | Fuel cell electrode and fuel cell |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3738831B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005302558A (en) * | 2004-04-13 | 2005-10-27 | Mitsubishi Rayon Co Ltd | Carbon electrode base and manufacturing method thereof |
| JP2008535178A (en) * | 2005-03-29 | 2008-08-28 | スリーエム イノベイティブ プロパティズ カンパニー | Oxidation stability microlayer of gas diffusion layer |
| JP4838729B2 (en) * | 2003-12-29 | 2011-12-14 | ユーティーシー パワー コーポレイション | Fuel cell having carbon fibers irregularly dispersed in a backing layer |
-
2001
- 2001-10-31 JP JP2001333990A patent/JP3738831B2/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4838729B2 (en) * | 2003-12-29 | 2011-12-14 | ユーティーシー パワー コーポレイション | Fuel cell having carbon fibers irregularly dispersed in a backing layer |
| JP2005302558A (en) * | 2004-04-13 | 2005-10-27 | Mitsubishi Rayon Co Ltd | Carbon electrode base and manufacturing method thereof |
| JP4559767B2 (en) * | 2004-04-13 | 2010-10-13 | 三菱レイヨン株式会社 | Carbon electrode substrate manufacturing method |
| JP2008535178A (en) * | 2005-03-29 | 2008-08-28 | スリーエム イノベイティブ プロパティズ カンパニー | Oxidation stability microlayer of gas diffusion layer |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3738831B2 (en) | 2006-01-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| WO2002073721A1 (en) | Gas diffusion electrode and fuel cell using this | |
| JP4528386B2 (en) | Solid polymer fuel cell and manufacturing method thereof | |
| US7625661B2 (en) | Diffusion media with continuous micro-porous layers incorporating non-uniformity | |
| JP3459615B2 (en) | Electrode for fuel cell and fuel cell | |
| KR20180058571A (en) | Component for fuel cell including graphene foam and functioning as flow field and gas diffusion layer | |
| JP2003178780A (en) | Polymer electrolyte type fuel cell system and operating method of polymer electrolyte type fuel cell | |
| CA2693522C (en) | Fuel cell with non-uniform catalyst | |
| JP2003109604A (en) | Gas diffusion electrode for fuel cell and method of manufacturing the same | |
| EP1383184B1 (en) | Electrode for fuel cell and method of manufacturing the electrode | |
| JP2023501791A (en) | MEMBRANE-ELECTRODE ASSEMBLY, MANUFACTURING METHOD THEREOF, AND FUEL CELL CONTAINING THE SAME | |
| JP4880131B2 (en) | Gas diffusion electrode and fuel cell using the same | |
| JP2007335163A (en) | Membrane catalyst layer assembly, membrane electrode assembly, and polymer-electrolyte fuel cell | |
| JP2001057217A (en) | Polymer electrolyte type fuel cell | |
| JP2006085984A (en) | Mea for fuel cell and fuel cell using this | |
| JP2009043688A (en) | Fuel cell | |
| JP3738831B2 (en) | Fuel cell electrode and fuel cell | |
| JP2005222720A (en) | Fuel cell | |
| JP2007149454A (en) | Gas diffusion layer, gas diffusion electrode, membrane electrode assembly and polymer electrolyte fuel cell | |
| JP5518721B2 (en) | FUEL CELL AND FUEL CELL STACK HAVING THE SAME | |
| JP2003109629A (en) | Method of manufacturing gas diffusion layer, and electrolyte film/electrode junction and polyelectrolyte fuel cell applying the same | |
| JP2004349013A (en) | Fuel cell stack | |
| JP6356436B2 (en) | Electrolyte membrane / electrode structure | |
| JP2002289201A (en) | Fuel cell | |
| JP2003142121A (en) | Solid high polymer type fuel cell | |
| JP2000228205A (en) | High polymer electrolyte fuel cell |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20040225 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20050502 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20050517 |
|
| RD02 | Notification of acceptance of power of attorney |
Free format text: JAPANESE INTERMEDIATE CODE: A7422 Effective date: 20050602 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20050715 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20050809 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20050928 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20051025 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20051025 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20091111 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20091111 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20101111 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20111111 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20121111 Year of fee payment: 7 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20121111 Year of fee payment: 7 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20131111 Year of fee payment: 8 |
|
| LAPS | Cancellation because of no payment of annual fees |