JPH0410185B2

JPH0410185B2 -

Info

Publication number: JPH0410185B2
Application number: JP59069870A
Authority: JP
Priority date: 1984-04-06
Filing date: 1984-04-06
Publication date: 1992-02-24
Also published as: JPS60236459A

Description

[Detailed description of the invention]

本発明は、燃料電池用電極基板に係り、更に詳
しくは、インタークーラーを有するセパレーター
と反応ガス流路としての中空孔道群を有する多孔
性炭素質層とが一体的に焼成された多層構造の燃
料電池用炭素質電極基板及びその製造方法に係
る。従来、不透過性の黒鉛製薄板をリブ細工して得
られるバイポーラセパレーターを用いるバイポー
ラセパレーター型燃料電池が公知である。これに対し、一方の面にリブを設け、他方の面
は平坦な電極面となつた構造を有し、リブ付き面
から反応ガスが平坦な電極面に拡散してくるモノ
ポーラ型電極基板が開発されて来ている。従来のモノポーラ型セルは、添付の第１図に示
すように、一方の面にリブ５を設け他方の面は平
坦な構造を有する電極基板１、触媒層２、電解質
を含浸させたマトリツクス３及びセパレーターシ
ート４から成つており、電極基板１のリブ付き面
から反応ガス（酸素又は水素）が平坦な電極面に
拡散してくるものである。一方、従来モノポーラ型燃料電池用電極基板の
製造方法としては、短炭素繊維をベースにしてプ
レス成形する方法（特開昭58−117649）、炭素繊
維を分散させた抄造法（特公昭53−18603）、炭素
繊維のウエブに熱分解炭素を化学的蒸着する方法
（米国特許第3829327号明細書）が提案されてい
る。これら従来の製造方法によつて得られる電極
基板は、いずれも全体的に均一な構造の一つの層
からなつている。このような均質単層の電極基板は、その嵩密度
が大きい場合、ガス拡散係数が小さいため限界電
流密度が小となるとともに電解液の保持量が充分
でないため性能の低下する時期が早くなる、すな
わち寿命が短いという欠点を有する。他方、その
嵩密度が小さい場合には、電気抵抗、熱抵抗が大
きく、曲げ強度などの機械的強度が低いという欠
点を有している。また、リブ構造を有する電極基板の場合、第１
図に示すように、片面が平面でないため断面係数
が小さくなり、例えばリブ５の根本のシヤープエ
ツジ部６に応力の集中が起こり、そのため全体と
しての強度面でいま一つ信頼の置けない面があつ
た。従つて、成型板としての強度を保つためには
平板部の肉厚を厚くするしかなく、そのためリブ
側から電極面側まで電極基板の全厚さを通つてガ
ス（炭素又は水素）が拡散する際の拡散抵抗が大
きくなるという欠点があつた。その上、リブ頂上
平面部分の平面性を完全なものにすることが困難
であり、セパレーターとの電気的及び熱的接触抵
抗が無視し得ない程大きくなる。一般に、これら
の接触抵抗は基板内の伝達抵抗の数倍にも達する
といわれており、従来のモノポーラ型電極基板は
接触抵抗が大きく、従つてセル間温度分布の不均
一性、発電効率の低下を招く可能性を有する。又、燃料電池のセル構成は、５〜８セルに一段
づつクーラを挿入しておりそれ等が全て、部材を
積層するという構成になつている。従来、ガス拡
散部−セパレーター−ガス拡散部の順で部材を積
層しており、そのための各部材間の電気的及び熱
的接触抵抗の問題がクローズアツプされている。
単位セル間の接触抵抗の問題は、セパレーター−
ガス拡散部を一体化した電極基板ができれば解決
されるが、セルーインタークーラー間の接触抵抗
は解決されずに残る。しかしインタークーラーは
通常カーボン板で作られており、空気又は温水を
供給する孔道を形成させる技術は知られておら
ず、片面に溝を切つたカーボン板を貼り合わせる
方法が提案されているのみであつた。この様な状
況で、セル・インタークーラー間の接触抵抗の問
題が残つたままになつている。カーボン板に中空孔道を形成させる方法として
は、一般的に、ボーリングが行なわれているが、
薄板で燃料電池の如く片長が60〜80cmに及ぶもの
については、それも不可能である。本発明は、上述の如き欠点を解消する燃料電池
用電極基板を提供することを目的とする。即ち、
本発明は、反応ガス流路用中空孔道群を有する多
孔性炭素質層がセパレーターの両側に一体的に焼
成されてなる燃料電池用電極基板であつて、セパ
レーターの厚みのほぼ中心部に冷却流体流路用中
空孔道群を設けたことを特徴とするインタークー
ラー内蔵燃料電池用電極基板を提供する。更に本
発明はこのように改良された燃料電池用電極基板
の製造方法を提供する。以下、添附図面を参照して本発明の電極基板を
詳述する。なお図面中同一部分に対しては第２図
乃至第４図で同一の参照番号を附してある。第２図に、本発明の電極基板の１例を示す。本
発明の電極基板１１は、２つの多孔性炭素質層
７，７の間にセパレーター８を挟んで一体的に焼
成して成る３層構造を有している。電極基板１１
のセパレーター８には、その厚みのほぼ中心部に
は冷却用流体（例えば空気又は温水）を流すため
の流路としての複数の中空孔道９′から成る中空
孔道群が設けられている。この冷却流体流路用中
空孔道群の各中空孔道は、互いに且つ電極基板の
電極面及び一側面に対してほぼ平行であり、電極
基板の一端面から相対する端面まで連続してい
る。冷却流体の流路としての中空孔道９′の断面形
状は任意でよく、例えば、第２図に示す如く円形
でもよい。この中空孔道９′の断面積を円の断面
積に換算した場合の円の直径に相当する寸法（相
当直径と称する）は、２〜10mmが好ましく、この
相当直径が２mmより小さいと電極基板面積が大き
くなり中空孔道の長さが長くなる場合には、冷却
流体流動の抵抗が大きくなり過ぎ、10mmより大き
いと中空孔道群を有するセパレーターが厚くなり
過ぎ電極基板を積層したセルの容積効率が減少す
る。本発明電極基板１１のセパレーター８は、その
中空孔道９′を除く部分が、1.2ｇ／cm³以上の平均
嵩密度と１×10^-4ml／cm・hr・mmAq.以下のガス
透過度と1kcal／ｍ・hr・℃以上の熱伝導度と10
×10^-3Ωcm以下の固有抵抗を有することが好まし
い。平均嵩密度が1.0ｇ／cm³より小さいとセパレ
ーターとしての所望の緻密性が得られない。本発明の電極基板１１の多孔性炭素質層７に
は、その厚みのほぼ中心部に反応ガス（酸素又は
水素）の流路として、複数本の中空孔道９からな
る中空孔道群が設けられている。この中空孔道９
は、電極基板１１の一端面から相対する端面まで
連続しており、各々の中空孔道９は互いにほぼ平
行であり且つ電極基板１１の電極面及び一側面に
対してほぼ平行であり、更にセパレーター８を挟
んで双方の中空孔群９は互いに直角の包囲を有す
る（第２図参照）。反応ガス流路用中空孔道９の断面形状は任意で
よく、例えば、第２図に示す如く矩形でもよい。
この中空孔道９′の断面積を円の断面積に換算し
た場合の円の直径に相当する寸法（相当直径と称
する）は、0.5〜３mmが好ましく、この相当直径
が0.5mmより小さいと電極基板面積が大きくなり
中空孔道の長さが長くなる場合には、反応ガス流
動の抵抗が大きくなり過ぎ、３mmより大きいと中
空孔道群９を有する多孔性炭素質層７が厚くなり
過ぎ電極基板を積層したセルの容積効率が減少す
る。本発明電極基板１１の多孔性炭素質層７は、均
質な多孔性炭素質材料から構成されており、その
平均嵩密度は0.4〜0.8ｇ／cm³であり、且つガス透
過度は20ml／cm・hr・mmAq.以上、熱伝導度は
0.7kcal／ｍ・hr・℃以上であることが好ましい。
上記範囲の平均嵩密度及びガス透過度を有する多
孔性炭素質層は、好ましい機械的強度例えば曲げ
強度を有し、且つ好ましいガス拡散抵抗を有す
る。なお、多孔性炭素質層の気孔率は50〜80％で
あり、その細孔は開細孔であり、且つ細孔の60％
以上が100μの範囲内の径を有することが好まし
い。本発明の電極基板１１の多孔性炭素質層７は、
上記のように均質単層とする代わりに、第３図及
び第４図に示す如く、反応ガス流路用中空孔道群
９の両側で嵩密度の異なる２層構造７，７′とす
ることができ、このようにするとより好ましい特
性（特に電気抵抗、曲げ強度等）を有する電極基
板が得られる。尚、この際、中空孔道群９よりセ
パレーター側の部分（セパレーター側層）７′は、
中空孔道群９より電極面側の部分（電極面側層）
７より大きい嵩密度を有する。第３図に、本発明の２層構造の多孔性炭素質層
を有する電極基板の１例を示す。第４図のセル
は、本発明の電極基板１１′を触媒層２及び電界
液層３を介して積層したものであり、第１図のセ
ル構造に相当する部分を番号１０で示す。第３図に示す如き本発明の電極基板１１′の電
極面側層７は前記の多孔性炭素質層７（第２図参
照）と同様な物性を有する。本発明の電極基板１１′のセパレーター側層
７′は、0.5〜1.0ｇ／cm³の平均嵩密度及び
0.9kcal／ｍ・hr・℃以上の熱伝導度を有するこ
とが好ましい。セパレーター側層７′はガス透過
度が小さいため、反応ガスは実質的に前記電極面
側層のみを拡散することになり、ガス拡散層が薄
くなる。又、得られる電極基板の強度例えば曲げ
強度が増大する。尚、本発明の電極基板１１′の前記電極面側層
７の厚さは、電極面側層７＋前記セパレーター側
層７′の全厚さの1/50〜1/2であることが好まし
い。本発明の電極基板は以下のようにして製造され
る。先ず冷却流体流路用中空孔道を有するセパレー
ターを製造する。即ち、所定形状の金型に、セパレーター用材
料、冷却流体流路用中空孔道形成材料及び該セパ
レーター用材料をこの順に供給し、プレス成形
し、後硬化させた後、焼成して、冷却流体流路用
中空孔道を有する焼成セパレーターを得る。ここで、セパレーター用材料としては、50μ以
下の粒径を有するカーボン粒子等の充填材50〜90
重量％及びフエノール樹脂等の熱硬化性樹脂結合
材50〜10重量％から成る混合物が用いられる。又
は50μ以下の粒径を有するカーボン粒子の表面に
にフエノール樹脂等をコーテイングした材料を用
いることもできる。尚、本発明に於いてカーボン
粒子としては、いわゆる黒鉛粒子も含めて炭素質
の粒子を意味する。又、結合材としてはフエノー
ル樹脂の他にピツチ又はこれとフアノール樹脂と
の混合物を用いることもできる。本発明で使用する冷却流体流路用中空孔道形成
用材料としては、クロス状織物、スダレ格市状成
形物等の高分子物質があり、この高分子物質とし
てはポリエチレン、ポリプロピレン、ポリスチレ
ン、ポリビニルアルコール、ポリ塩化ビニルがあ
り、炭化収率30重量％以下のものを適宜選択す
る。炭化収率がこれより高いと中空孔道の形成及
び相当直径の調節に難点を生ずる恐れがある。ま
た、これらの高分子物質としては、中空孔道形成
のために、少なくとも100℃にて揮発もしくは溶
融流動を示さないものが用いられる。すなわち、
該高分子物質は、成形温度および圧力において、
熱変形は許されるが揮発もしくは溶融流動しては
ならない。中空孔道の相当直径を好ましい範囲に調節する
ために使用できるクロス状織物としては、第５ａ
図に示すように、前記高分子物質からなる繊維径
(d)が2.2〜11mmの単糸又は単糸を複数本収束した
収束糸を、ガス流れ方向に平行な単糸又は収束糸
の間隔（Ｔ）が３〜30mm、ガス流れに直角な方向
の単糸又は収束糸の間隔(L)が５〜100mmとなるよ
うに織成したものである。又、同様に使用できる
スダレ格子状成形物は、前記高分子物質を金型に
溶融状態で押出成形する方法、又は該高分子物質
のペレツト又は粉末を金型内で加圧成形する方法
で作られるが、スダレ格子の格子断面は円形、矩
形、正方形又は星形など任意の形状とすることが
できる。その断面寸法は、格子断面積を相当する
円の断面積に換算した時の該換算円の直径（相当
直径）が2.2〜11mmとなるように選択するが、例
えば第５ｂ図に示すように断面が矩形の場合ｄ＝
２〜９mm、ｈ＝2.2〜10mmの範囲から格子の相当
直径が2.2〜11mmとなるように選択する。スダレ
格子のガス流れ方向に平行な格子の間隔（Ｔ）は
３〜30mmとし、ガス流れに直角な方向の格子の間
隔(L)は５〜100mmの範囲から目的により選ばれる。これらクロス状織物又はスダレ格子状成形物は
金型内で電極基板を形成する際、該セパレーター
のほぼ中央部に位置するように、セパレーター用
材料の上に載せればよく、その後の加圧成形、後
硬化の工程を経て、炭化焼成により炭化する部分
を除いて、大部分が熱分解により揮散してセパレ
ーター内に中空孔道を形成するようになる。一般にこのような中空孔道形成に際して、炭化
焼成後常温まで冷却した時、始めの繊維径又は成
形体格子の相当直径は、これにより形成される中
空孔道口経が３〜７％小さくなることが確かめら
れているので、この収縮を勘案して、原料のクロ
ス状織物又はスダレ格子状成形物の繊維径又は相
当直径を選ぶことにより、好ましい中空孔道の相
当直径が得られるように任意の調節することがで
きる。尚、上記クロス状織物、スダレ格子状成形物
は、本発明の中空孔道形成用材料を例示したもの
であり、本発明はこれらのみに限定されない。
又、同様に前記の高分子物質も同様な特性を有す
るものならば前記以外のものも使用し得る。本発明の冷却流体流路用中空孔道含有セパレー
ターの成形はプレス成形によつて行なう。プレス
成形条件は、金型加熱温度120〜160℃、成形圧２
〜150Kg／cm²、圧保持時間10〜60分から適宜選択
する。典型的には、130℃、80Kg／cm²、30分であ
る。プレス成形後、得られた成形物を成形温度で少
なくとも２時間以上後硬化させた後、不活性雰囲
気下800〜3000℃で約１時間焼成する。この際、
低温の熱分解過程に於いて約700℃まではゆつく
り例えば100±50℃／時で昇温し、ガス化時の急
激な収縮による圧力発生を防ぐことが好ましい。
この低温の熱分解過程で急激な昇温を行なうと層
間剥離、クラツク発生の原因となる。尚、本発明の電極基板の製造方法に於いては、
上記のように焼成して得た冷却流体流路用中空孔
道含有焼成セパレーターを使用する代わりに、上
述の如くプレス成形したままでのプレス成形セパ
レーターを焼成せずに後の工程に付すこともでき
る。第２図に示す如き、均質単層の多孔性炭素質層
を有する本発明の電極基板は、上記のように製造
した焼成セパレーター又はプレス成形セパレータ
ー（焼成する前のもの）を用いて次のように製造
する。即ち、所定形状の金型に多孔性炭素質層用材
料、反応ガス流路用中空孔道形成用材料及び前記
多孔性炭素質層用材料をこの順に供給し、次に上
記焼成セパレーター又はプレス成形セパレーター
を供給し、更に前記多孔性炭素質層用材料、前記
反応ガス流路用中空孔道形成用材料及び前記多孔
性炭素質層用材料をこの順に供給し、プレス成形
し、後硬化させた後、一体的に焼成する。本発明で使用する多孔性炭素質層用材料として
は、充填材10〜50重量％、結合材20〜40重量％及
び細孔調節材20〜50重量％から成る混合物があ
る。多孔性炭素質層用材料の、充填材としては短炭
素繊維、カーボン粒子等、結合材としてはフエノ
ール樹脂、エポキシ樹脂、石油系及び／又は石炭
系ピツチ、又はこれらの混合物、細孔調節材とし
てはポリビニルアルコール、ポリスチレン、ポリ
エチレン、ポリプロピレン、ポリ塩化ビニル又は
これらの混合物が使用される。充填材として用いる短炭素繊維は、５〜30μの
繊維径、0.02〜２mm程度の繊維長を有するものが
好ましい。繊維長が２mmを越えると、成形に至る
工程で、お互いにからみ合い、毛玉状になり、所
望の嵩密度及び細孔径分布が得られない。なお、
0.02mmより短いと必要とする強度が得られない。
また、該短炭素繊維を2000℃に焼成した場合の炭
化線収縮率は0.1〜3.0％の範囲である。線収縮率
がこれより大であると、焼成時におけるクラツク
発生の原因の一つになる恐れがある。このような
短炭素繊維を用いると特に大型の電極基板の製造
が可能となる。本発明に用いる結合材は、炭化後炭素質結合材
として炭素繊維間の結合に役立つものであり、所
望の嵩密度を得るためには、炭化収率が30〜75重
量％の範囲の樹脂が好ましい。このような結合材
としてフエノール樹脂、エポキシ樹脂、石油系及
び／又は石炭系ピツチ、又はこれらの混合物があ
る。特に、粉体フエノール樹脂単独もしくはこれ
と粉体ピツチとの混合物は、乾式混合に際して最
も好ましく、得られる基板の特性も優れることが
判明した。また結合材樹脂の混合量は10〜50重量
％、好ましくは20〜40重量％が用いられ、10重量
％より少ないと結合材としての量が不足するため
に得られる電極基板の強度が低くなり、また50重
量％より多いと所望の細孔径およびガス透過度が
得られなくなる。本発明に用いる細孔調節材は成形品の細孔を定
める重要な材料である。本発明においては、嵩密
度及び細孔径を調整するために、70％以上の粒子
が30〜300μの範囲の粒径を有する有機粒状物質
が用いられる。有機粒状物質としては、少なくと
も100℃にて揮発もしくは溶融流動を示さないも
のが用いられる。すなわち、該有機粒状物質は、
成形温度および圧力において、熱変形は許される
が揮発もしくは溶融流動してはならない。上記の
理由から好ましい細孔調節材としては、ポリビニ
ルアルコール、ポリ塩化ビニル、ポリエチレン、
ポリプロピレン、ポリスチレン又はこれらの混合
物で、炭化収率30重量％以下のものを適宜選択す
る。炭化収率がこれより高いと嵩密度、細孔径の
調整に難点を生ずる恐れがある。細孔調節材の添加量は、所望とする電極基板の
嵩密度および細孔径に応じて20〜50重量％の範囲
から選ばれる。尚、場合に際し充填材をＡ、結合
材をＢ、細孔調節材をＣとして各々重量％で示し
た場合、（Ａ＋Ｃ）／Ｂ＝1.5〜4.0の範囲に各成
分を調整すると好ましい結果が得られる。この範
囲外では嵩密度、曲げ強度、ガス透過度、電気抵
抗のすべてを満足することは難しい。本発明に於
いて、充填材Ａが10〜50重量％、細孔調節材Ｃが
20〜50％の範囲に対しては、結合材Ｂが20〜40重
量％の範囲から選ばれることが好ましい。本発明で使用する反応ガス流路用中空孔道形成
用材料としては、前述したセパレーター内の冷却
流体流路用中空孔道形成用材料と同様のものが用
いられる。中空孔道の相当直径を好ましい範囲に調節する
ために使用できるクロス状織物としては、第５ａ
図に示すように、前記高分子物質からなる繊維径
(d)が0.5〜3.3mmの単糸又は単糸を複数本収束した
収束糸を、ガス流れ方向に平行な単糸又は収束糸
の間隔（Ｔ）が1.5〜５mm、ガス流れに直角な方
向の単糸又は収束糸の間隔(L)が５〜50mmとなるよ
うに織成したものである。又、同様に使用できる
スダレ格子状成形物は、前記高分子物質を金型に
溶融状態で押出成形する方法、又は該高分子物質
のペレツト又は粉末を金型内で加圧成形する方法
で作られるが、スダレ格子の格子断面は円形、矩
形、正方形又は星形など任意の形状とすることが
できる。その断面寸法は、格子断面積を相当する
円の断面積に換算した時の該換算円の直径（相当
直径）が0.5〜3.3mmとなるように選択するが、例
えば第５ｂ図に示すように断面が矩形の場合ｄ＝
0.45〜2.7mm、ｈ＝0.5〜3.3mmの範囲から格子の相
当直径が0.5〜3.3mmとなるように選択する。スダ
レ格子のガス流れ方向に平行な格子の間隔（Ｔ）
は1.5mmとし、ガス流れに直角な方向の格子の間
隔(L)は５〜50mmの範囲から目的により選ばれる。これらクロス状織物又はスダレ格子状成形物は
金型内で電極基板を形成する際、該多孔性炭素質
層のほぼ中央部に位置するように、該多孔性炭素
質層用材料の上に載せればよく、その後の加圧成
形、後硬化の工程を経て、炭化焼成により炭化す
る部分を除いて、大部分が熱分解により揮散して
多孔性炭素質層内に中空孔道を形成するようにな
る。プレス成形条件は、金型加熱温度70〜200℃、
成形圧５〜100Kg／cm²、圧保持時間10〜60分の範
囲から適宜選択する。プレス成形後、得られた成形物を成形温度で少
なくとも２時間以上後硬化させた後、不活性雰囲
気下800〜3000℃で約１時間焼成する。この際、
低温の熱分解過程に於いて約700℃まではゆつく
り例えば100±50℃／時で昇温し、ガス化時の急
激な収縮による応力発生を防ぐことが好ましい。
この低温の熱分解過程で急激な昇温を行なうと層
間剥離、クラツク発生の原因となる。第３図に示す如き多孔性炭素質層が２層構造を
有する本発明の電極基板は、上述の焼成又はプレ
ス成形セパレーターを用いて以下のように製造さ
れる。尚、多孔性炭素質層は、セパレーターと同
時に一体的に成形するか又は多孔性炭素質層のみ
を別途予備成形し、その後セパレーターと共に一
体焼成するという２通りの方法がある。１つの方法では、所定形状の金型に、多孔性炭
素質層の電極面側用材料、反応ガス流路用中空孔
道形成用材料、セパレーター側層用材料を順に供
給し、前記焼成セパレーター又はプレス成形セパ
レーターを供給し、更に該セパレーター側層用材
料、前記反応ガス流路用中空孔道形成用材料、前
記電極面側層用材料を順に供給し、次いで、プレ
ス成形し、後硬化させた後、一体的に焼成する。ここで、電極面側層用材料は前記多孔性炭素質
層用材料と同様であり、セパレーター側層用材料
を除く他の材料は夫々前記したものと同様であ
る。本発明で使用するセパレーター側層用材料とし
ては、前記多孔性炭素質層用材料と同様なものが
使用できる。例えば、充填材30〜70重量％、結合
材20〜40重量％及び細孔調節材10〜30重量％から
成る混合物が挙げられ、各材料の例は多孔性炭素
質層用混合物に用いるものと同様である。一例を
挙げると平均繊維長が１mm以下の短炭素繊維40〜
60wt％、100〜300μの範囲に粒径分布を示すポリ
ビニルアルコール粒子10〜30wt％、粒径100μ以
下の粉末フエノール樹脂25〜35wt％をヘンシエ
ルミキサー等の混合機により混合して得られる混
合物がある。この混合物中の短炭素繊維の平均繊
維長は、多孔性炭素質層用混合物に使用した短炭
素繊維より0.1〜0.3mm短く、ポリビニルアルコー
ル粒子の配合比は多孔性炭素質層用混合物中の配
合比より５〜20wt％少なくする。その他の材料
及び操作条件は前記と同様である。第２の方法では、所定形状の金型に、前記セパ
レーター側層用材料、反応ガス流路用中空孔道形
成用材料及び電極面側層用材料をこの順に供給
し、60〜100℃、20〜50Kg／cm²、10〜30分、典型
的には80℃、30Kg／cm²、20分の条件で予備プレス
成形し、次いで同様な操作を繰り返して同様な予
備成形多孔性炭素質層を２個得た後、いずれか１
つを電極面側層が下側になるように金型に供給
し、次に前記焼成セパレーター又はプレス成形セ
パレーターを供給し、更に前記予備成形多孔炭素
質層を電極面側層が上側になるように供給し、
130〜160℃、20〜50Kg／cm²、10〜30分、典型的に
は140℃、40Kg／cm²、20分の条件で本プレス成形
を行なう。その後、後硬化し更に焼成する。この場合、各段階に於ける材料及び操作条件は
上記のとおりである。以上のような本発明方法により製造される電極
基板は、機械的強度例えば曲げ強度が大きく、
又、薄片化が可能で反応ガスの拡散層を薄くで
き、ガス拡散抵抗が小さくなり、電流密度が大き
くなる。更に、インタークーラーを内蔵するセパ
レーターシートが一体的に成形されているため、
従来のセパレーターシート及びインタークーラー
は不要となり価値低減と同時に熱的及び電気的接
触抵抗が皆無となる。この結果、積層した場合の
全体としての電気抵抗及び熱抵抗が激減するな
ど、多大の効果が発揮される。このように、本発
明の電極基板は理想的なものといえる。因みに、
炭素繊維抄造法による炭素繊維ペーパー型に比較
して、曲げ強度が大になると同時にリブ付黒鉛板
が不要となり、価値の低下、更に電気抵抗の低下
が期待できる。本発明の電極基板によつて得られる効果を一層
明確にするため、本発明の電極基板と従来のリブ
付モノポーラ型電極基板（第１図参照）の諸物性
値を比較対照して第１表に示す。尚、これらの物
性値は比較のために一例として示すものであり、
同様な条件で測定したものである。 The present invention relates to an electrode substrate for a fuel cell, and more particularly, the present invention relates to a fuel cell having a multilayer structure in which a separator having an intercooler and a porous carbonaceous layer having a group of hollow holes as a reaction gas flow path are integrally fired. The present invention relates to a carbonaceous electrode substrate and a method for manufacturing the same. Conventionally, a bipolar separator type fuel cell using a bipolar separator obtained by ribbing an impermeable graphite thin plate is known. In response, a monopolar electrode substrate has been developed that has ribs on one surface and a flat electrode surface on the other surface, allowing reactive gas to diffuse from the ribbed surface to the flat electrode surface. It's been happening. As shown in the attached FIG. 1, a conventional monopolar cell includes an electrode substrate 1 having ribs 5 on one surface and a flat structure on the other surface, a catalyst layer 2, a matrix 3 impregnated with an electrolyte, and It consists of a separator sheet 4, in which reactive gas (oxygen or hydrogen) diffuses from the ribbed surface of the electrode substrate 1 to the flat electrode surface. On the other hand, conventional methods for manufacturing electrode substrates for monopolar fuel cells include a press-forming method using short carbon fibers as a base (Japanese Patent Publication No. 58-117649), a paper-making method using dispersed carbon fibers (Japanese Patent Publication No. 53-18603). ), a method of chemical vapor deposition of pyrolytic carbon onto a web of carbon fibers (U.S. Pat. No. 3,829,327) has been proposed. The electrode substrates obtained by these conventional manufacturing methods all consist of a single layer with an entirely uniform structure. When such a homogeneous single-layer electrode substrate has a large bulk density, the gas diffusion coefficient is small, so the limiting current density is small, and the amount of electrolyte retained is not sufficient, so the performance deteriorates earlier. In other words, it has the disadvantage of a short lifespan. On the other hand, when the bulk density is low, it has the drawbacks of high electrical resistance, high thermal resistance, and low mechanical strength such as bending strength. In addition, in the case of an electrode substrate having a rib structure, the first
As shown in the figure, since one side is not flat, the section modulus becomes small, and stress concentration occurs, for example, at the sharp edge part 6 at the root of the rib 5, making the overall strength even more unreliable. Ta. Therefore, in order to maintain the strength of the molded plate, there is no choice but to increase the thickness of the flat plate part, which causes gas (carbon or hydrogen) to diffuse through the entire thickness of the electrode substrate from the rib side to the electrode surface side. The disadvantage was that the diffusion resistance at the time of use increased. Moreover, it is difficult to perfect the flatness of the top plane portion of the rib, and the electrical and thermal contact resistance with the separator becomes so large that it cannot be ignored. In general, these contact resistances are said to reach several times the transmission resistance within the substrate, and conventional monopolar electrode substrates have high contact resistance, resulting in uneven temperature distribution between cells and a decrease in power generation efficiency. There is a possibility that this may lead to Further, the cell structure of the fuel cell is such that a cooler is inserted one stage at a time in each of 5 to 8 cells, and all of them are constructed by laminating members. Conventionally, members are laminated in the order of gas diffusion section, separator, and gas diffusion section, and the problem of electrical and thermal contact resistance between the respective members has been highlighted.
The problem of contact resistance between unit cells is that the separator
This problem would be solved if an electrode substrate with an integrated gas diffusion section was created, but the contact resistance between cell and intercooler remains unsolved. However, intercoolers are usually made of carbon plates, and there is no known technology for forming holes for supplying air or hot water, and the only proposed method is to bond carbon plates with grooves cut on one side. Ta. Under these circumstances, the problem of contact resistance between the cell and intercooler remains. Boring is generally used to form hollow holes in a carbon plate.
This is also impossible for thin plates with lengths of 60 to 80 cm, such as fuel cells. An object of the present invention is to provide an electrode substrate for a fuel cell that eliminates the above-mentioned drawbacks. That is,
The present invention is an electrode substrate for a fuel cell in which a porous carbonaceous layer having a group of hollow holes for a reaction gas flow path is integrally fired on both sides of a separator, in which a cooling fluid is provided at approximately the center of the thickness of the separator. Provided is an electrode substrate for a fuel cell with a built-in intercooler, characterized in that a group of hollow holes for flow paths is provided. Furthermore, the present invention provides a method of manufacturing the thus improved electrode substrate for fuel cells. Hereinafter, the electrode substrate of the present invention will be described in detail with reference to the accompanying drawings. Note that the same parts in the drawings are given the same reference numerals in FIGS. 2 to 4. FIG. 2 shows an example of the electrode substrate of the present invention. The electrode substrate 11 of the present invention has a three-layer structure formed by sandwiching a separator 8 between two porous carbonaceous layers 7, 7 and integrally firing them. Electrode substrate 11
The separator 8 is provided with a hollow hole group consisting of a plurality of hollow holes 9' as a flow path for flowing a cooling fluid (for example, air or hot water) approximately at the center of its thickness. The hollow holes in the cooling fluid channel group are substantially parallel to each other and to the electrode surface and one side surface of the electrode substrate, and are continuous from one end surface to the opposite end surface of the electrode substrate. The cross-sectional shape of the hollow hole passage 9' serving as a flow path for the cooling fluid may be arbitrary, and may be circular as shown in FIG. 2, for example. When the cross-sectional area of the hollow hole path 9' is converted to the cross-sectional area of a circle, the dimension corresponding to the diameter of the circle (referred to as the equivalent diameter) is preferably 2 to 10 mm. If this equivalent diameter is smaller than 2 mm, the electrode substrate area If the length of the hollow hole becomes large and the length of the hollow hole becomes long, the resistance to the flow of the cooling fluid becomes too large, and if it is larger than 10 mm, the separator with the hollow hole group becomes too thick, reducing the volumetric efficiency of the cell with laminated electrode substrates. do. The separator 8 of the electrode substrate 11 of the present invention has an average bulk density of 1.2 g/cm ³ or more and a gas permeability of 1×10 ^-4 ml/cm・hr・mmAq. or less, excluding the hollow holes 9′. Thermal conductivity of 1kcal/m・hr・℃ or more and 10
It is preferable to have a specific resistance of ×10 ⁻³ Ωcm or less. If the average bulk density is less than 1.0 g/cm ³ , the desired density as a separator cannot be obtained. In the porous carbonaceous layer 7 of the electrode substrate 11 of the present invention, a hollow hole group consisting of a plurality of hollow holes 9 is provided as a flow path for a reactive gas (oxygen or hydrogen) approximately at the center of its thickness. There is. This hollow hole road 9
are continuous from one end surface of the electrode substrate 11 to the opposite end surface, and each hollow hole path 9 is substantially parallel to each other and substantially parallel to the electrode surface and one side surface of the electrode substrate 11, and the separator 8 Both hollow hole groups 9 surround each other at right angles to each other (see FIG. 2). The cross-sectional shape of the hollow passageway 9 for the reaction gas flow path may be arbitrary, and may be rectangular as shown in FIG. 2, for example.
The dimension corresponding to the diameter of a circle when the cross-sectional area of the hollow hole path 9' is converted to the cross-sectional area of a circle (referred to as the equivalent diameter) is preferably 0.5 to 3 mm, and if this equivalent diameter is smaller than 0.5 mm, the electrode substrate If the area becomes large and the length of the hollow holes becomes long, the resistance to flow of the reactant gas will become too large, and if it is larger than 3 mm, the porous carbonaceous layer 7 having the hollow holes 9 will become too thick, making it difficult to stack the electrode substrate. The volumetric efficiency of the cell decreases. The porous carbonaceous layer 7 of the electrode substrate 11 of the present invention is made of a homogeneous porous carbonaceous material, and has an average bulk density of 0.4 to 0.8g/cm ³ and a gas permeability of 20ml/cm・HR・mmAq. or more, thermal conductivity is
It is preferable that it is 0.7kcal/m・hr・℃ or more.
A porous carbonaceous layer having an average bulk density and gas permeability in the above ranges has favorable mechanical strength, such as bending strength, and has favorable gas diffusion resistance. The porosity of the porous carbonaceous layer is 50 to 80%, and the pores are open, and 60% of the pores are open.
It is preferred that the diameter is within the range of 100μ. The porous carbonaceous layer 7 of the electrode substrate 11 of the present invention is
Instead of forming a homogeneous single layer as described above, as shown in FIGS. 3 and 4, it is possible to form a two-layer structure 7, 7' with different bulk densities on both sides of the hollow hole channel group 9 for the reaction gas flow path. By doing so, an electrode substrate having more preferable properties (especially electrical resistance, bending strength, etc.) can be obtained. In addition, at this time, the part on the separator side (separator side layer) 7' from the hollow hole path group 9 is as follows.
The part closer to the electrode surface than the hollow hole path group 9 (electrode surface side layer)
It has a bulk density greater than 7. FIG. 3 shows an example of an electrode substrate having a porous carbonaceous layer having a two-layer structure according to the present invention. The cell shown in FIG. 4 is obtained by laminating electrode substrates 11' of the present invention with a catalyst layer 2 and an electrolyte layer 3 interposed therebetween, and a portion corresponding to the cell structure shown in FIG. 1 is designated by numeral 10. The electrode surface side layer 7 of the electrode substrate 11' of the present invention as shown in FIG. 3 has physical properties similar to those of the porous carbonaceous layer 7 (see FIG. 2). The separator side layer 7' of the electrode substrate 11' of the present invention has an average bulk density of 0.5 to 1.0 g/cm ³ and
It is preferable to have a thermal conductivity of 0.9 kcal/m·hr·°C or more. Since the separator side layer 7' has a low gas permeability, the reaction gas substantially diffuses only through the electrode surface side layer, resulting in a thin gas diffusion layer. Moreover, the strength of the obtained electrode substrate, for example, the bending strength, is increased. The thickness of the electrode side layer 7 of the electrode substrate 11' of the present invention is preferably 1/50 to 1/2 of the total thickness of the electrode side layer 7+the separator side layer 7'. The electrode substrate of the present invention is manufactured as follows. First, a separator having hollow holes for cooling fluid passages is manufactured. That is, a separator material, a material for forming hollow holes for a cooling fluid flow path, and the separator material are supplied in this order to a mold having a predetermined shape, press-molded, post-cured, and fired to form a cooling fluid flow path. A fired separator having hollow holes for road use is obtained. Here, as a material for the separator, a filler such as carbon particles having a particle size of 50μ or less is used.
A mixture of 50-10% by weight of a thermosetting resin binder such as a phenolic resin is used. Alternatively, it is also possible to use a material in which the surface of carbon particles having a particle size of 50 μm or less is coated with a phenol resin or the like. In the present invention, carbon particles refer to carbonaceous particles including so-called graphite particles. In addition to phenolic resin, pitch or a mixture of pitch and phenolic resin can also be used as the binding material. The material for forming the hollow holes for the cooling fluid flow path used in the present invention includes polymeric substances such as cloth-like fabrics and cross-shaped molded articles. Examples of the polymeric substances include polyethylene, polypropylene, polystyrene, and polyvinyl alcohol. , polyvinyl chloride, and one with a carbonization yield of 30% by weight or less is appropriately selected. If the carbonization yield is higher than this, there may be difficulties in forming hollow pores and controlling the equivalent diameter. Further, as these polymeric substances, those that do not volatilize or exhibit melt flow at at least 100° C. are used in order to form hollow pores. That is,
At the molding temperature and pressure, the polymeric material
Thermal deformation is permitted, but volatilization or melt flow is prohibited. The cross-shaped fabric that can be used to adjust the equivalent diameter of the hollow hole to a preferable range includes No. 5a.
As shown in the figure, the diameter of the fiber made of the polymeric substance is
(d) is 2.2 to 11 mm single yarn or convergent yarn made of multiple single yarns converged. It is woven so that the distance (L) between single yarns or convergent yarns is 5 to 100 mm. In addition, a sudare lattice molded product that can be used in the same manner can be produced by extruding the polymeric substance in a molten state into a mold, or by press-molding pellets or powder of the polymeric substance in a mold. However, the lattice cross section of the Sudare lattice can be of any shape such as circular, rectangular, square, or star-shaped. The cross-sectional dimensions are selected so that when the grid cross-sectional area is converted to the cross-sectional area of the corresponding circle, the diameter of the converted circle (equivalent diameter) is 2.2 to 11 mm. If is a rectangle then d=
The grid is selected from the ranges of 2 to 9 mm and h = 2.2 to 10 mm so that the equivalent diameter of the grid is 2.2 to 11 mm. The grid spacing (T) of the Sudare grid parallel to the gas flow direction is 3 to 30 mm, and the grid spacing (L) in the direction perpendicular to the gas flow is selected from a range of 5 to 100 mm depending on the purpose. When forming an electrode substrate in a mold, these cross-like woven fabrics or sudare lattice-like molded products may be placed on the separator material so as to be located approximately in the center of the separator, and then press-molded. After undergoing a post-curing process, most of the material, except for the part that is carbonized by carbonization firing, is volatilized by thermal decomposition to form hollow pores within the separator. In general, when forming such hollow holes, it has been confirmed that when cooled to room temperature after carbonization firing, the initial fiber diameter or equivalent diameter of the compact lattice is 3 to 7% smaller than the diameter of the hollow holes formed. Therefore, by taking this shrinkage into consideration and selecting the fiber diameter or equivalent diameter of the raw material cross-like fabric or sudare lattice molding, arbitrary adjustment can be made so as to obtain a preferable equivalent diameter of the hollow hole. I can do it. It should be noted that the above-mentioned cross-like woven fabric and sudare lattice-like molded product are examples of the material for forming hollow pores of the present invention, and the present invention is not limited to these.
Similarly, polymer materials other than those described above may also be used as long as they have similar characteristics. The hollow hole-containing separator for the cooling fluid flow path of the present invention is formed by press molding. Press molding conditions are mold heating temperature 120-160℃, molding pressure 2
~150Kg/cm ² and pressure retention time 10 to 60 minutes, appropriately selected. Typically, the temperature is 130°C, 80Kg/cm ² , and 30 minutes. After press molding, the obtained molded product is post-cured at the molding temperature for at least 2 hours or more, and then fired at 800 to 3000° C. for about 1 hour in an inert atmosphere. On this occasion,
In the low-temperature pyrolysis process, it is preferable to raise the temperature slowly up to about 700°C, for example at a rate of 100±50°C/hour, to prevent pressure generation due to rapid contraction during gasification.
If the temperature is rapidly increased during this low-temperature thermal decomposition process, delamination and cracks may occur. In addition, in the method for manufacturing an electrode substrate of the present invention,
Instead of using the fired separator containing hollow holes for the cooling fluid flow path obtained by firing as described above, it is also possible to use the press-formed separator as-is press-formed as described above and submit it to the subsequent process without firing. . The electrode substrate of the present invention having a homogeneous single-layer porous carbonaceous layer as shown in FIG. Manufactured to. That is, a material for a porous carbonaceous layer, a material for forming a hollow hole for a reaction gas flow path, and the material for the porous carbonaceous layer are supplied in this order to a mold having a predetermined shape, and then the fired separator or the press-molded separator is supplied. After supplying the material for the porous carbonaceous layer, the material for forming the hollow pores for the reaction gas flow path, and the material for the porous carbonaceous layer in this order, press-forming, and post-curing, Fired in one piece. The material for the porous carbonaceous layer used in the present invention is a mixture comprising 10-50% by weight of filler, 20-40% by weight of binder and 20-50% by weight of pore control material. For porous carbonaceous layer materials, short carbon fibers, carbon particles, etc. are used as fillers, phenol resins, epoxy resins, petroleum-based and/or coal-based pitches, or mixtures thereof are used as binders, and pore control materials are used as fillers. Polyvinyl alcohol, polystyrene, polyethylene, polypropylene, polyvinyl chloride or mixtures thereof are used. The short carbon fibers used as the filler preferably have a fiber diameter of 5 to 30 μm and a fiber length of about 0.02 to 2 mm. If the fiber length exceeds 2 mm, the fibers will become entangled with each other during the molding process and become pill-like, making it impossible to obtain the desired bulk density and pore size distribution. In addition,
If it is shorter than 0.02mm, the required strength cannot be obtained.
Further, when the short carbon fiber is fired at 2000°C, the carbonization line shrinkage rate is in the range of 0.1 to 3.0%. If the linear shrinkage rate is higher than this, it may be one of the causes of cracks during firing. Using such short carbon fibers makes it possible to manufacture particularly large electrode substrates. The binder used in the present invention serves as a carbonaceous binder for bonding between carbon fibers after carbonization, and in order to obtain the desired bulk density, a resin with a carbonization yield of 30 to 75% by weight is required. preferable. Such binders include phenolic resins, epoxy resins, petroleum-based and/or coal-based pitches, or mixtures thereof. In particular, it has been found that powdered phenolic resin alone or a mixture of this and powdered pitch is most preferred during dry mixing, and the properties of the resulting substrate are also excellent. In addition, the amount of the binder resin mixed is 10 to 50% by weight, preferably 20 to 40% by weight. If it is less than 10% by weight, the strength of the electrode substrate obtained will be low because the amount as a binder is insufficient. , and if it exceeds 50% by weight, the desired pore size and gas permeability cannot be obtained. The pore control material used in the present invention is an important material that defines the pores of a molded article. In the present invention, an organic particulate material in which 70% or more of the particles have a particle size in the range of 30 to 300 microns is used in order to adjust the bulk density and pore size. As the organic particulate material, one that does not volatilize or exhibit melt flow at at least 100°C is used. That is, the organic particulate material is
At molding temperatures and pressures, thermal deformation is allowed, but volatilization or melt flow is not allowed. For the above reasons, preferred pore control materials include polyvinyl alcohol, polyvinyl chloride, polyethylene,
Polypropylene, polystyrene, or a mixture thereof with a carbonization yield of 30% by weight or less is appropriately selected. If the carbonization yield is higher than this, it may be difficult to adjust the bulk density and pore diameter. The amount of the pore control material added is selected from a range of 20 to 50% by weight depending on the desired bulk density and pore diameter of the electrode substrate. In addition, when the filler is A, the binder is B, and the pore control material is C, each expressed in weight percent, favorable results can be obtained by adjusting each component to a range of (A + C) / B = 1.5 to 4.0. It will be done. Outside this range, it is difficult to satisfy all of the bulk density, bending strength, gas permeability, and electrical resistance. In the present invention, the filler A is 10 to 50% by weight and the pore control material C is
For a range of 20-50%, it is preferred that binder B is selected from a range of 20-40% by weight. As the material for forming the hollow pores for the reaction gas flow path used in the present invention, the same material as the material for forming the hollow pores for the cooling fluid flow path in the separator described above is used. The cross-shaped fabric that can be used to adjust the equivalent diameter of the hollow hole to a preferable range includes No. 5a.
As shown in the figure, the diameter of the fiber made of the polymeric substance is
(d) is 0.5 to 3.3 mm single yarn or convergent yarn made of multiple converged single yarns, parallel to the gas flow direction, and the interval (T) between single yarns or convergent yarns is 1.5 to 5 mm, in the direction perpendicular to the gas flow. It is woven so that the distance (L) between single yarns or convergent yarns is 5 to 50 mm. In addition, a sudare lattice molded product that can be used in the same manner can be produced by extruding the polymeric substance in a molten state into a mold, or by press-molding pellets or powder of the polymeric substance in a mold. However, the lattice cross section of the Sudare lattice can be of any shape such as circular, rectangular, square, or star-shaped. Its cross-sectional dimensions are selected so that when the grid cross-sectional area is converted to the cross-sectional area of the corresponding circle, the diameter of the converted circle (equivalent diameter) is 0.5 to 3.3 mm. For example, as shown in Figure 5b, If the cross section is rectangular, d=
The grid is selected from a range of 0.45 to 2.7 mm and h=0.5 to 3.3 mm so that the equivalent diameter of the grating is 0.5 to 3.3 mm. Grid spacing (T) parallel to the gas flow direction of the Sudare grid
is 1.5 mm, and the grid spacing (L) in the direction perpendicular to the gas flow is selected from a range of 5 to 50 mm depending on the purpose. When forming an electrode substrate in a mold, these cross-like fabrics or sudare lattice moldings are placed on the material for the porous carbonaceous layer so as to be located approximately in the center of the porous carbonaceous layer. Then, through the subsequent pressure forming and post-curing steps, most of the carbonized carbonized carbonized layer is volatilized by thermal decomposition to form hollow pores within the porous carbonaceous layer. Become. Press molding conditions are mold heating temperature 70-200℃,
The molding pressure is appropriately selected from the range of 5 to 100 kg/cm ² and the pressure holding time of 10 to 60 minutes. After press molding, the obtained molded product is post-cured at the molding temperature for at least 2 hours or more, and then fired at 800 to 3000° C. for about 1 hour in an inert atmosphere. On this occasion,
In the low-temperature pyrolysis process, it is preferable to raise the temperature slowly up to about 700°C, for example at a rate of 100±50°C/hour, to prevent the generation of stress due to rapid contraction during gasification.
If the temperature is rapidly increased during this low-temperature thermal decomposition process, delamination and cracks may occur. The electrode substrate of the present invention having a porous carbonaceous layer having a two-layer structure as shown in FIG. 3 is manufactured as follows using the above-mentioned fired or press-molded separator. There are two methods for forming the porous carbonaceous layer: one is to form the porous carbonaceous layer integrally with the separator, or the other is to separately preform only the porous carbonaceous layer and then to sinter the porous carbonaceous layer together with the separator. In one method, a material for the electrode surface side of the porous carbonaceous layer, a material for forming hollow pores for the reaction gas flow path, and a material for the separator side layer are sequentially supplied to a mold having a predetermined shape, and then the fired separator or press After supplying a molded separator, further supplying the material for the separator side layer, the material for forming the hollow holes for the reaction gas flow path, and the material for the electrode surface side layer in this order, and then press-molding and post-curing, Fired in one piece. Here, the material for the electrode side layer is the same as the material for the porous carbonaceous layer, and the other materials except for the material for the separator side layer are the same as those described above. As the material for the separator side layer used in the present invention, the same materials as those for the porous carbonaceous layer can be used. Examples include mixtures consisting of 30-70% filler, 20-40% binder and 10-30% pore control material, examples of each material being used in the porous carbonaceous layer mixture. The same is true. For example, short carbon fiber with an average fiber length of 1 mm or less
A mixture obtained by mixing 60 wt%, 10 to 30 wt% of polyvinyl alcohol particles with a particle size distribution in the range of 100 to 300 μ, and 25 to 35 wt% of powdered phenolic resin with a particle size of 100 μ or less using a mixer such as a Henschel mixer. be. The average fiber length of the short carbon fibers in this mixture is 0.1 to 0.3 mm shorter than the short carbon fibers used in the mixture for the porous carbonaceous layer, and the blending ratio of polyvinyl alcohol particles is the same as that in the mixture for the porous carbonaceous layer. 5 to 20 wt% less than the ratio. Other materials and operating conditions were the same as above. In the second method, the material for the separator side layer, the material for forming hollow holes for the reaction gas flow path, and the material for the electrode surface side layer are supplied in this order to a mold having a predetermined shape, and Pre-press molding is performed at 50 Kg/cm ² for 10-30 minutes, typically at 80°C and 30 Kg/cm ² for 20 minutes, and then the same operation is repeated to form two similar pre-formed porous carbonaceous layers. After getting one, either one
one of the preformed porous carbonaceous layers is supplied to the mold so that the electrode side layer is on the bottom, then the fired separator or press-molded separator is supplied, and then the preformed porous carbonaceous layer is placed on the mold so that the electrode side layer is on the top. supply to,
Main press molding is carried out under the conditions of 130 to 160°C, 20 to 50 kg/cm ² for 10 to 30 minutes, typically 140°C, 40 kg/cm ² for 20 minutes. Thereafter, it is post-cured and further fired. In this case, the materials and operating conditions at each step are as described above. The electrode substrate manufactured by the method of the present invention as described above has high mechanical strength, for example, bending strength,
In addition, it is possible to make it into thin pieces, so the diffusion layer of the reaction gas can be made thinner, the gas diffusion resistance becomes smaller, and the current density becomes larger. Furthermore, since the separator sheet containing the intercooler is integrally molded,
Conventional separator sheets and intercoolers are no longer required, reducing value and simultaneously eliminating thermal and electrical contact resistance. As a result, great effects such as a drastic reduction in electrical resistance and thermal resistance as a whole when laminated are exhibited. Thus, the electrode substrate of the present invention can be said to be ideal. By the way,
Compared to the carbon fiber paper mold made by the carbon fiber papermaking method, the bending strength is increased and at the same time, a ribbed graphite plate is not required, so a reduction in value and further reduction in electrical resistance can be expected. In order to further clarify the effects obtained by the electrode substrate of the present invention, Table 1 compares and contrasts the physical properties of the electrode substrate of the present invention and a conventional monopolar electrode substrate with ribs (see Figure 1). Shown below. These physical property values are shown as an example for comparison.
Measured under similar conditions.

【表】以下、本発明を実施例により詳述するが、本発
明は以下の実施例に限定されるものではない。実施例１スダレ格子状ポリプロピレン成形物の製造ペレツト状の市販ポリプロピレン（東燃石油(株)
製、品番Ｊ−215）を、スクリユー型射出成形機
を用いて、温度230℃、射出圧力500Kg／cm²の条件
で溶融して押出し、約50℃に保持された金型に流
し込み、第５ｂ図に示す如き格子断面が円形のス
ダレ格子状ポリプロピレン成形物（反応ガス流路
用中空孔道形成用材料）を作つた。使用金型は第５ｂ図のスダレ格子状成形物の格
子断面が直径0.85mmの円で、Ｔ＝2.5mm、Ｌ＝40
mmを与える溝をステンレス板に切削加工したもの
で、ステンレス製の蓋板をつけ分割できるものと
した。又、同様にして、格子断面が直径7.4mmの円で、
Ｔ＝10mm、Ｌ＝80mmの成形物（冷却流体流路用中
空孔道形成用材料）を作製した。実施例２平均粒径40μのカーボン粒子（日本黒鉛商事社
製）70wt％とフエノール樹脂（旭有機材K.K.製）
30wt％から成る均一混合物（セパレーター用混
合物）をプレス成形用金型に供給し、次に、実施
例１で製造した冷却流体流路用中孔道成形用材料
（スダレ格子状ポリプロピレン成形物）を供給し、
更に、上記セパレーター用混合物を供給した。次に、130℃、80Kg／cm²で30分間プレス成形し
た。（尚、このプレス成形品は後述の実施例４及
び５に示すように、電極基板の製造にこのままで
使用し得た。）得られたプレス成形品を140℃で約２時間後硬
化した後、2000℃で１時間窒素雰囲気下で焼成し
て焼成セパレーターを得た。この焼成セパレータ
ーを用いる電極基板の製造例を後述の実施例３に
示す。実施例３短炭素繊維（呉羽化学製、平均繊維長0.45mmＭ
−104S、）40wt％と細孔調節材としてポリビニル
アルコール粒子（日本合成化学K.K.製）30wt％
及び結合材としてフエノール樹脂（旭有機材K.
K.製）30wt％からなる混合物（多孔性炭素質層
用混合物）を、プレス成形用金型に供給し、次
に、実施例１で製造した反応ガス流路用中空孔道
形成用材料を供給し、更に、上記多孔性炭素質層
用混合物を供給した。その後、実施例２で製造し
た焼成セパレーターを供給した。更に、上記多孔
性炭素質層用混合物、上記中空孔道形成用材料、
上記多孔性炭素質層用混合物をこの順に供給し
た。その後、130℃、40Kg／cm²で20分間プレス成
形した。成形物を約２時間150℃で後硬化させた
後100℃／時で700℃までゆつくり昇温し、更に
2000℃で１時間窒素雰囲気下で焼成した。得られた電極基板は第２図に示したような３層
構造を有しており、反応ガス流路用及び冷却流体
流路用中空孔道は断面がほぼ円形でその直径は
夫々約0.8mm及び約７mmであつた。この電極基板
の諸物性値を第２表に示す。[Table] Hereinafter, the present invention will be explained in detail with reference to examples, but the present invention is not limited to the following examples. Example 1 Production of polypropylene molded product in the form of a lattice Pellet-like commercially available polypropylene (Tonen Sekiyu Co., Ltd.)
(product number J-215) was melted and extruded using a screw-type injection molding machine at a temperature of 230°C and an injection pressure of 500 kg/ ^cm2 , and poured into a mold maintained at about 50°C. A lattice-shaped polypropylene molded product (material for forming hollow holes for reaction gas channels) with a circular lattice cross section as shown in the figure was prepared. The mold used is a circle with a lattice cross section of 0.85 mm in diameter, T = 2.5 mm, and L = 40 mm.
It was made by cutting a groove into a stainless steel plate to provide a diameter of mm, and a stainless steel cover plate was attached to it so that it could be divided. Also, in the same way, the grid cross section is a circle with a diameter of 7.4 mm,
A molded article (material for forming hollow holes for cooling fluid channels) with T=10 mm and L=80 mm was produced. Example 2 Carbon particles with an average particle size of 40μ (manufactured by Nippon Graphite Shoji Co., Ltd.) 70wt% and phenol resin (manufactured by Asahi Yokuzai KK)
A homogeneous mixture (mixture for separator) consisting of 30 wt% was supplied to a press molding die, and then the material for forming a hollow channel for a cooling fluid flow path (sudare lattice-shaped polypropylene molded product) produced in Example 1 was supplied. death,
Furthermore, the above separator mixture was supplied. Next, it was press-molded at 130° C. and 80 kg/cm ² for 30 minutes. (In addition, as shown in Examples 4 and 5 described later, this press-formed product could be used as it was for manufacturing an electrode substrate.) After curing the obtained press-formed product at 140°C for about 2 hours, A fired separator was obtained by firing at 2000°C for 1 hour in a nitrogen atmosphere. An example of manufacturing an electrode substrate using this fired separator is shown in Example 3 below. Example 3 Short carbon fiber (manufactured by Kureha Chemical, average fiber length 0.45mmM
-104S, ) 40wt% and polyvinyl alcohol particles (manufactured by Nippon Gosei KK) as a pore control material 30wt%
and phenolic resin (Asahi Yukizai K.
A mixture (mixture for porous carbonaceous layer) consisting of 30 wt% (manufactured by K. K.) was supplied to a press molding die, and then the material for forming hollow pores for the reaction gas flow path produced in Example 1 was supplied. Furthermore, the above porous carbonaceous layer mixture was supplied. Thereafter, the fired separator produced in Example 2 was supplied. Furthermore, the above-mentioned porous carbonaceous layer mixture, the above-mentioned material for forming hollow pores,
The above mixture for porous carbonaceous layer was supplied in this order. Thereafter, it was press-molded at 130° C. and 40 kg/cm ² for 20 minutes. After post-curing the molded product at 150℃ for about 2 hours, the temperature was slowly raised to 700℃ at 100℃/hour, and then
It was fired at 2000°C for 1 hour in a nitrogen atmosphere. The obtained electrode substrate had a three-layer structure as shown in Fig. 2, and the hollow holes for the reaction gas flow path and the cooling fluid flow path were approximately circular in cross section, and their diameters were approximately 0.8 mm and 1.5 mm, respectively. It was about 7mm. Table 2 shows the physical properties of this electrode substrate.

【表】【table】

【表】実施例４短炭素繊維（呉羽化学製、平均繊維長0.45mmＭ
−104S、）40wt％と細孔調節材としてポリビニル
アルコール粒子（日本合成化学K.K.製）30wt％
及び結合材としてフエノール樹脂（旭有機材製
K.K.製）30wt％からなる混合物（電極面側用混
合物）を、プレス成形用金型に供給し、次に、実
施例１で製造した反応ガス流路用中空孔道形成用
材料を供給し、更に、上記短炭素繊維50wt％、
上記ポリビニルアルコール20wt％および上記フ
エノール樹脂30wt％からなる混合物（セパレー
ター側層用混合物）を供給した。その後、実施例
２でプレス成形したまでのセパレーターを供給し
た。更に、上記セパレーター側層用混合物、上記
反応ガス流路用中空孔道形成用材料、上記電極面
側層用混合物をこの順に供給した。その後、130
℃、40Kg／cm²で20分間プレス成形した。成形物を
約２時間150℃で後硬化させた後100℃／時で700
℃までゆつくり昇温し、更に2000℃で１時間窒素
雰囲気下で焼成した。得られた電極基板は第３図に示したような３層
構造を有しており、反応ガス流路用及び冷却流体
流路用中空孔道は断面がほぼ円形でその直径は
夫々約0.8mm及び約７mmであつた。この電極基板
の諸物性値を第３表に示す。[Table] Example 4 Short carbon fiber (manufactured by Kureha Chemical, average fiber length 0.45mmM
-104S, ) 40wt% and polyvinyl alcohol particles (manufactured by Nippon Gosei KK) as a pore control material 30wt%
and phenolic resin as a binding material (manufactured by Asahi Yukizai Co., Ltd.)
A mixture (mixture for the electrode surface side) consisting of 30 wt% (manufactured by KK) was supplied to a press molding die, then the material for forming hollow holes for the reaction gas flow path produced in Example 1 was supplied, and then , the above short carbon fiber 50wt%,
A mixture (mixture for separator side layer) consisting of 20 wt% of the above polyvinyl alcohol and 30 wt% of the above phenolic resin was supplied. Thereafter, the separator press-molded in Example 2 was supplied. Furthermore, the mixture for the separator side layer, the material for forming hollow holes for the reaction gas flow path, and the mixture for the electrode side layer were supplied in this order. then 130
Press molding was carried out at 40 Kg/cm ² for 20 minutes at ℃. After post-curing the molded product at 150℃ for about 2 hours, it was cured at 100℃/hour to 700℃.
The temperature was slowly raised to 0.degree. C., and then fired at 2000.degree. C. for 1 hour in a nitrogen atmosphere. The obtained electrode substrate has a three-layer structure as shown in Fig. 3, and the hollow holes for the reaction gas flow path and the cooling fluid flow path are approximately circular in cross section, and the diameters are approximately 0.8 mm and 3.5 mm, respectively. It was about 7mm. Table 3 shows the physical properties of this electrode substrate.

【表】【table】

【表】実施例５実施例４のセパレーター側層用混合物、実施例
１の反応ガス流路用中空孔道形成用材料、更に実
施例４の電極面側用混合物を金型に供給し、80
℃、30Kg／cm²、20分間予備成形し、予備成形品を
金型から取り出した。同様にして同じ予備成形品
を調製した。次に、上記予備成形品を電極面側層
が下側になるようにして金型に供給し、次に実施
例２で得たプレス成形セパレーター（焼成前）を
供給し、更に上記予備成形品を電極面側層が上側
になるようにして金型に供給した。その後130℃、
40Kg／cm²で20分間プレス成形した。約２時間140
℃で後硬化させた後、100℃／時で700℃までゆつ
くり昇温し、更に2000℃で１時間窒素雰囲気下で
焼成した。得られた成形品は実施例４と同様な構
造、物性を有していた。[Table] Example 5 The mixture for the separator side layer of Example 4, the material for forming hollow holes for the reaction gas flow path of Example 1, and the mixture for the electrode surface side of Example 4 were supplied to a mold,
Preforming was carried out at 30 Kg/cm ² for 20 minutes at ℃, and the preform was taken out from the mold. Identical preforms were prepared in a similar manner. Next, the above preformed product is supplied to the mold with the electrode side layer facing downward, then the press molded separator obtained in Example 2 (before firing) is supplied, and then the above preformed product was supplied to the mold with the electrode side layer facing upward. Then 130℃,
Press molding was carried out at 40 kg/cm ² for 20 minutes. Approximately 2 hours 140
After post-curing at 100°C, the temperature was slowly raised to 700°C at a rate of 100°C/hour, and further baked at 2000°C for 1 hour in a nitrogen atmosphere. The obtained molded article had the same structure and physical properties as Example 4.

[Brief explanation of drawings]

第１図は、従来のモノポーラ型燃料電池セル構
造を示す斜視図、第２図は、本発明の電極基板一
例の構造を示す斜視図、第３図は、本発明の別の
電極基板の構造を示す斜視図、第４図は、本発明
の電極基板を積み重ねたセル構造を示す斜視図、
第５ａ図は本発明で使用するクロス状織物の概略
図、第５ｂ図は本発明で使用するスダレ格子状成
形物の１例の概略図である。１……電極基板、２……触媒層、３……マトリ
ツクス、４……セパレーターシート、５……リ
ブ、７……多孔性炭素質層（電極面側層）、７′…
…セパレーター側層、８……セパレーター、９…
…反応ガス流路用中空孔道、９′……冷却流体流
路用中空孔道、１１，１１′……本発明電極基板。 FIG. 1 is a perspective view showing a conventional monopolar fuel cell structure, FIG. 2 is a perspective view showing the structure of an example of an electrode substrate of the present invention, and FIG. 3 is a structure of another electrode substrate of the present invention. FIG. 4 is a perspective view showing a cell structure in which electrode substrates of the present invention are stacked,
FIG. 5a is a schematic diagram of a cross-shaped fabric used in the present invention, and FIG. 5b is a schematic diagram of an example of a sudare lattice molded product used in the present invention. DESCRIPTION OF SYMBOLS 1... Electrode substrate, 2... Catalyst layer, 3... Matrix, 4... Separator sheet, 5... Rib, 7... Porous carbonaceous layer (electrode side layer), 7'...
...Separator side layer, 8...Separator, 9...
...Hollow hole path for reaction gas flow path, 9'...Hollow hole path for cooling fluid flow path, 11, 11'... Electrode substrate of the present invention.

Claims

[Scope of Claims] 1. An electrode substrate for a fuel cell, in which a porous carbonaceous layer having a group of hollow holes for a reaction gas flow path is integrally fired on both sides of a separator, the electrode substrate having a porous carbonaceous layer having a group of hollow holes for a reaction gas flow path, which is formed by firing a porous carbonaceous layer integrally on both sides of a separator, the electrode substrate having a porous carbonaceous layer having a group of hollow holes for a reaction gas flow path. An electrode substrate for a fuel cell with a built-in intercooler, characterized in that a group of hollow holes for a cooling fluid flow path is provided in the electrode substrate for a fuel cell with a built-in intercooler. 2 Each hollow hole path in the hollow hole path group for cooling fluid flow path is
Claims characterized in that they are substantially parallel to each other and to the electrode surface and one side of the electrode substrate, are continuous from one end surface of the electrode substrate to the opposite end surface, and have an equivalent diameter of 2 to 10 mm. The electrode substrate according to item 1. 3 The part of the separator excluding the hollow hole group for the cooling fluid flow path has a bulk density of 1.2 g/cm ³ or more, 1 × 10 ^-4
Gas permeability below cm ² /hr・mmAq., 1kcal/m・
The electrode substrate according to claim 1 or 2, characterized in that it has a thermal conductivity of hr·° C. or more and a specific resistance of 10×10 ⁻³ Ωcm or less. 4 Each hollow hole in the group of hollow holes for reaction gas flow path is as follows:
They are approximately parallel to each other and to the electrode surface and one side of the electrode substrate, and are continuous from one side of the electrode substrate to the opposite end surface, and both hollow hole groups for reaction gas flow paths are perpendicular to each other with a separator in between. It has an orientation of , and the equivalent diameter of each hollow hole is
The electrode substrate according to any one of claims 1 to 3, characterized in that the thickness is 0.5 to 3 mm. 5 The porous carbonaceous layer consists of a single homogeneous layer, with an average bulk density of 0.4 to 0.8 g/ ^cm3 , a porosity of 50 to 80%, and a gas permeability of 20 ml/cm・hr・mmAq. and has a thermal conductivity of 0.7kcal/m・hr・℃ or more, and is further characterized in that its pores are open pores, and 60% or more of the pores have a diameter of 100μ or less. An electrode substrate according to any one of claims 1 to 4. 6. The porous carbonaceous layer has a two-layer structure with different bulk densities on both sides of the group of hollow holes for the reaction gas flow path, and the bulk density of the layer on the separator side from the hollow holes is closer to the electrode surface than the hollow holes. 5. The electrode substrate according to claim 1, wherein the electrode substrate has a bulk density greater than that of the layer. 7 The electrode surface side layer has an average bulk density of 0.4 to 0.8 g/ ^cm3 , a porosity of 50 to 80%, a gas permeability of 20 ml/cm・hr・mmAq. or more, and 0.7 kcal/m・hr・℃ or more Claim 6, wherein the pores are open and 60% or more of the pores have a diameter of 100μ or less. electrode substrate. 8 Claim 6, characterized in that the separator side layer has an average bulk density of 0.5 to 1.0 g/cm ³ and a thermal conductivity of 0.9 kcal/m・hr・℃ or more.
7. The electrode substrate according to item 7. 9 A fuel cell electrode substrate in which a porous carbonaceous layer having a group of hollow holes for a reaction gas flow path is integrally fired on both sides of a separator, and (a) a cooling fluid flow is formed approximately at the center of the thickness of the separator. A method for manufacturing an electrode substrate for a fuel cell with a built-in intercooler having a hollow hole for road use, the method comprising: (a) placing a separator material in a mold having a predetermined shape;
A step of sequentially supplying a material for forming a hollow hole for a cooling fluid flow path and the material for the separator, press-molding, post-curing, and firing to produce a fired separator having a hollow hole for a cooling fluid flow path; and (b) feeding a material for a porous carbonaceous layer, a material for forming a hollow hole for a reaction gas flow path, and a material for the porous carbonaceous layer in order into a mold having a predetermined shape, and then in step (a). The obtained fired separator is supplied, and further the material for the porous carbonaceous layer, the material for forming the hollow pores for the reaction gas flow path, and the material for the porous carbonaceous layer are supplied in this order, and then press-molded, A method comprising post-curing followed by integral firing. 10 A patent characterized in that the separator material is a mixture consisting of 50 to 90% by weight of a filler such as carbon particles having a particle size of 50μ or less and 50 to 10% by weight of a thermosetting resin binder such as a phenolic resin. The method according to claim 9. 11. The method according to claim 10, wherein the separator material is a material obtained by coating the surface of carbon particles with a particle size of 50 μm or less with phenol resin or the like. 12. The method according to any one of claims 9 to 11, wherein the material for forming the hollow holes for the cooling fluid flow path is a polymeric substance. 13. The method according to claim 12, wherein the polymeric substance does not volatilize or exhibit melt flow at at least 100°C. 14. A patent claim characterized in that the polymeric material is selected from the group consisting of polyethylene, polypropylene, polystyrene, polyvinyl alcohol, and polyvinyl chloride, and the carbonization yield of the polymeric material is 30% by weight or less. The method according to scope item 13. 15. The method according to any one of claims 12 to 14, characterized in that the material for forming the hollow holes for the cooling fluid flow path is a cross-like fabric or a grid-like molded product of the polymeric substance. Method. 16. Claim 15, characterized in that the cross-like fabric is woven from a single yarn or a convergent yarn made by converging a plurality of single yarns made of the polymeric substance and having a fiber diameter of 2.2 to 11 mm. the method of. 17. Claims characterized in that the interval between single yarns or convergent yarns parallel to the gas flow direction is 3 to 30 mm, and the interval between single yarns or convergent yarns in the direction perpendicular to the gas flow is 5 to 100 mm. The method according to paragraph 16. 18 The Sudare lattice-shaped molded product is manufactured by extruding the polymeric substance in a molten state into a mold, or by press-molding pellets or powder of the polymeric substance in a mold. 16. The method according to claim 15, wherein the grating cross section has an equivalent diameter of 2.2 to 11 mm. 19 The grid spacing parallel to the gas flow direction is 3 to 30
19. A method according to claim 18, characterized in that the grid spacing in the direction perpendicular to the gas flow is between 5 and 100 mm. 20 Claim 9, characterized in that the material for the porous carbonaceous layer is a mixture consisting of 10 to 50% by weight of filler, 20 to 40% by weight of binder, and 20 to 50% by weight of pore control material. 20. The method according to any one of items 1 to 19. 21. The method according to claim 20, wherein the filler is short carbon fibers or carbon particles. 22 Short carbon fibers have a fiber diameter of 5 to 30μ and a fiber length.
22. The method according to claim 21, wherein the method has a carbonization line shrinkage rate of 0.1 to 3.0% when fired at 2000° C. and 0.02 to 2 mm. 23 The binding material is phenolic resin, epoxy resin,
21. The method according to claim 20, characterized in that the binder is petroleum and/or coal-based pitch or a mixture thereof, and the carbonization yield of the binder is 30 to 75% by weight. 24 The pore control material has 70% or more particles of 30~
21. Process according to claim 20, characterized in that the organic particulate material has a particle size of 300μ. 25 The organic particulate matter is polyvinyl alcohol,
25. A method according to claim 24, characterized in that the material is polyvinyl chloride, polyethylene, polypropylene, polystyrene or a mixture thereof. 26. The method according to any one of claims 9 to 25, wherein the material for forming the hollow pores for the reaction gas flow path is a polymeric substance. 27. The method according to claim 26, characterized in that the polymeric substance does not volatilize or exhibit melt flow at at least 100°C. 28. A patent claim characterized in that the polymeric substance is selected from the group consisting of polyethylene, polypropylene, polystyrene, polyvinyl alcohol, and polyvinyl chloride, and the carbonization yield of the polymeric substance is 30% by weight or less. The method according to scope item 27. 29. The method according to any one of claims 26 to 28, characterized in that the material for forming the hollow pores for the reaction gas flow path is a cross-like fabric or a lattice-like molded product of the polymeric substance. Method. 30. Claim 29, characterized in that the cross-like fabric is woven from a single yarn or a convergent yarn made by converging a plurality of single yarns made of the polymeric substance and having a fiber diameter of 0.5 to 3.3 mm. Method described. 31 Claims characterized in that the interval between single yarns or convergent yarns parallel to the gas flow direction is 1.5 to 5 mm, and the interval between single yarns or convergent yarns in the direction perpendicular to the gas flow is 5 to 50 mm. The method according to paragraph 30. 32 The Sudare lattice-shaped molded product is manufactured by extruding the polymeric substance in a molten state into a mold, or by press-molding pellets or powder of the polymeric substance in a mold. 30. The method according to claim 29, wherein the grating cross section has an equivalent diameter of 0.5 to 3.3 mm. 33 The grid spacing parallel to the gas flow direction is 1.5~
33. A method according to claim 32, characterized in that the grid spacing in the direction perpendicular to the gas flow is between 5 and 50 mm. 34 Claim 9, characterized in that the press molding conditions in step (a) are a mold heating temperature of 120 to 160°C, a molding pressure of 2 to 150 Kg/cm ² , and a pressure holding time of 10 to 60 minutes. The method according to any one of Items 33 to 33. 35. A method according to any of claims 9 to 34, characterized in that the post-curing of step (a) is carried out at the molding temperature for at least 2 hours. 36 Firing in step (a) under an inert atmosphere
36. A method according to any one of claims 9 to 35, characterized in that it is carried out at 3000° C. for about 1 hour. 37. Claim 9, characterized in that the press molding conditions in step (b) are a mold heating temperature of 70 to 160°C, a molding pressure of 5 to 100 Kg/cm ² , and a pressure holding time of 1 to 60 minutes. 37. The method according to any one of Items 36 to 36. 38. A method according to any of claims 9 to 37, characterized in that the post-curing of step (b) is carried out at the molding temperature for at least 2 hours. 39 Firing in step (b) under an inert atmosphere
39. A method according to any one of claims 9 to 38, characterized in that it is carried out at 3000° C. for about 1 hour. 40 An electrode substrate for a fuel cell in which a porous carbonaceous layer having a group of hollow holes for a reaction gas flow path is integrally fired on both sides of a separator, and (a) a cooling fluid flow is formed approximately at the center of the thickness of the separator. A method for manufacturing an electrode substrate for a fuel cell with a built-in intercooler having a hollow hole for road use, the method comprising: (a) placing a separator material in a mold having a predetermined shape;
a step of sequentially supplying a material for forming a hollow hole for a cooling fluid flow path and the material for the separator and press-molding the material to produce a press-molded separator; The material, the material for forming hollow pores for the reaction gas flow path, and the material for the porous carbonaceous layer are supplied in this order, and then the press-molded separator obtained in step (a) is supplied, and then the porous carbonaceous layer is supplied. a material for forming the hollow pores for the reaction gas flow path, and a material for the porous carbonaceous layer, which are then press-molded, post-cured, and then integrally fired. . 41 Claim 40, characterized in that the press molding conditions in step (a) are a mold heating temperature of 120 to 160°C, a molding pressure of 2 to 150 Kg/cm ² , and a pressure holding time of 10 to 60 minutes. The method described in. 42 Claim 40, characterized in that the main press molding conditions in step (b) are a mold heating temperature of 120 to 160°C, a molding pressure of 20 to 50 Kg/cm ² , and a pressure holding time of 10 to 30 minutes. or the method described in paragraph 41. 43 An electrode substrate for a fuel cell in which a porous carbonaceous layer having a group of hollow holes for a reaction gas flow path is integrally fired on both sides of a separator, and (a) a cooling fluid flow is formed approximately at the center of the thickness of the separator. (b) An electrode substrate for a fuel cell with a built-in intercooler, wherein the porous carbonaceous layer has a two-layer structure having different bulk densities on both sides of the group of hollow holes for the reaction gas flow path. A manufacturing method, comprising: (a) placing a separator material in a mold having a predetermined shape;
A step of sequentially supplying a material for forming a hollow hole for a cooling fluid flow path and the material for the separator, press-molding, post-curing, and firing to produce a fired separator having a hollow hole for a cooling fluid flow path; and (b) sequentially supplying a material for the electrode surface side layer of the porous carbonaceous layer, a material for forming hollow pores for the reaction gas flow path, and a material for the separator side layer of the porous carbonaceous layer into a mold having a predetermined shape. Then, the fired separator obtained in step (a) is supplied, and further a material for the separator side layer of the porous carbonaceous layer, a material for forming the hollow pores for the reaction gas flow path, and the porous carbonaceous layer are supplied. A method comprising the steps of sequentially supplying electrode surface side layer materials, followed by press molding, post-curing, and integrally firing. 44 A patent characterized in that the material for the electrode side layer of the porous carbonaceous layer is a mixture consisting of 10 to 50% by weight of filler, 20 to 40% by weight of binder, and 20 to 50% by weight of pore control material. A method according to claim 43. 45 A patent characterized in that the material for the separator side layer of the porous carbonaceous layer is a mixture consisting of 30 to 70% by weight of filler, 20 to 40% by weight of binder, and 10 to 30% by weight of pore control material. The method according to claim 43 or 44. 46 An electrode substrate for a fuel cell in which a porous carbonaceous layer having a group of hollow holes for a reaction gas flow path is integrally fired on both sides of a separator, and (a) a cooling fluid flow is formed approximately at the center of the thickness of the separator. (b) An electrode substrate for a fuel cell with a built-in intercooler, wherein the porous carbonaceous layer has a two-layer structure having different bulk densities on both sides of the group of hollow holes for the reaction gas flow path. A manufacturing method, comprising: (a) placing a separator material in a mold having a predetermined shape;
a step of sequentially supplying a material for forming hollow holes for a cooling fluid flow path and the material for the separator and press-molding the material to produce a press-molded separator; and (b) placing a porous carbonaceous layer in a mold having a predetermined shape. The material for the electrode side layer, the material for forming the hollow pores for the reaction gas flow path, and the material for the separator side layer of the porous carbonaceous layer are supplied in this order, and then the press-molded separator obtained in step (a) is supplied. , furthermore, a material for the separator side layer of the porous carbonaceous layer, a material for forming the hollow pores for the reaction gas flow path,
A method comprising the steps of sequentially supplying a material for the electrode side layer of the porous carbonaceous layer, then performing main press molding, post-curing, and then integrally firing. 47 An electrode substrate for a fuel cell in which a porous carbonaceous layer having a group of hollow holes for a reaction gas flow path is integrally fired on both sides of a separator, and (a) a cooling fluid flow is formed approximately at the center of the thickness of the separator. (b) An electrode substrate for a fuel cell with a built-in intercooler, wherein the porous carbonaceous layer has a two-layer structure having different bulk densities on both sides of the group of hollow holes for the reaction gas flow path. A manufacturing method, comprising: (a) placing a separator material in a mold having a predetermined shape;
A step of sequentially supplying a material for forming a hollow hole for a cooling fluid flow path and the material for the separator, press-molding, post-curing, and firing to produce a fired separator having a hollow hole for a cooling fluid flow path; (b) A material for the separator side layer of the porous carbonaceous layer, a material for forming the hollow pores for the reaction gas flow path, and a material for the electrode surface side layer of the porous carbonaceous layer are sequentially supplied to a mold having a predetermined shape, (c) Preforming the preformed porous carbonaceous layer obtained in step (b) with gold so that the electrode surface side layer is on the lower side. feeding into a mold, then feeding the fired separator obtained in step (a), and further feeding the preformed porous carbonaceous layer obtained in step (b) so that the separator side layer is on the lower side, Next, the method includes the step of performing main press molding, post-curing, and then integrally firing. 48 Claim 47, characterized in that the preliminary press molding conditions in step (b) are a mold heating temperature of 60 to 100°C, a molding pressure of 20 to 50 Kg/cm ² , and a pressure holding time of 10 to 30 minutes. The method described in section. 49 Claim 47, wherein the main press molding conditions in step (c) are a mold heating temperature of 120 to 160°C, a molding pressure of 20 to 50 Kg/cm ² , and a pressure holding time of 10 to 30 minutes. or the method described in paragraph 48. 50 An electrode substrate for a fuel cell in which a porous carbonaceous layer having a group of hollow holes for a reaction gas flow path is integrally fired on both sides of a separator, and (a) a cooling fluid flow is formed approximately at the center of the thickness of the separator. (b) An electrode substrate for a fuel cell with a built-in intercooler, wherein the porous carbonaceous layer has a two-layer structure having different bulk densities on both sides of the group of hollow holes for the reaction gas flow path. A manufacturing method, comprising: (a) placing a separator material in a mold having a predetermined shape;
A step of sequentially supplying a material for forming a hollow hole for a cooling fluid flow path and the material for the separator and press-molding the material to produce a press-molded separator, (b) placing a porous carbonaceous layer separator in a mold having a predetermined shape; The material for the side layer, the material for forming the hollow pores for the reaction gas flow path, and the material for the electrode surface side layer of the porous carbonaceous layer are supplied in this order, and pre-press molded.
(c) supplying the preformed porous carbonaceous layer obtained in step (b) to a mold with the electrode surface side layer facing downward; Next, the press-molded separator obtained in step (a) is supplied, and further step (b)
A method comprising the step of supplying the preformed porous carbonaceous layer obtained in step 1 with the separator side layer facing downward, then performing main press molding, post-curing, and then integrally firing.