JP3547960B2

JP3547960B2 - Fuel cell material coating device, fuel cell material coating method, and fuel cell material film forming method using the same

Info

Publication number: JP3547960B2
Application number: JP32499497A
Authority: JP
Inventors: 伸二竹内; 淳一藤田; 力岩澤; 正孝望月; 雅克永田; 波子兼田
Original assignee: Fujikura Ltd; Kansai Electric Power Co Inc
Current assignee: Fujikura Ltd; Kansai Electric Power Co Inc
Priority date: 1997-11-26
Filing date: 1997-11-26
Publication date: 2004-07-28
Anticipated expiration: 2017-11-26
Also published as: JPH11162482A

Description

【０００１】
【発明の属する技術分野】
本発明は、燃料電池材料塗布装置、燃料電池材料の塗布方法およびそれを用いた燃料電池材料の成膜方法に関する。
【０００２】
【従来の技術】
従来、円筒縦縞方式の固体電解質型燃料電池として、たとえば、特開平７−２６３００１号公報に記載され、また図７に示す構造の固体電解質型燃料電池１１０が提案されている。この従来の固体電解質型燃料電池１１０は、中心部に燃料供給用導電性チューブ１１１を挿入する構造を特徴としていて、内側から順に燃料極１１２、固体電解質１１３、空気極１１４を形成し、中心部に燃料噴出のために多孔質にした燃料供給用導電性チューブ１１１を挿入し、この導電性チューブ１１１と燃料極１１２との間に燃料改質機能を持つ導電性フェルト１１５を充填し、そして導電性チューブ１１１に燃料ガス１１６を供給し、外周に空気１１７を流通させるようにした構造である。
【０００３】
この固体電解質型燃料電池１１０の発電作用について説明すると、電池１１０の導電性チューブ１１１内に天然ガス、メタン、石炭ガス化ガスなどの燃料ガス１１６を供給し、導電性チューブ１１１の多孔質の管壁を通じて導電性フェルト１１５の部分に噴出させ、この導電性フェルト１１５と燃料極１１２と固体電解質１１３の部分で高温度条件下、通常、６５０℃〜１０５０℃の条件下で次の化１式の改質反応を起こさせる。
【０００４】
【化１】

この改質反応で発生する水素に対して、固体電解質１１３を介して対極する燃料極１１２と空気極１１４との部分で次の化２式の発電反応を起こし、遊離した電子を集電することによって発電力を得る。
【０００５】
【化２】

つまり、燃料極１１２においては化２（ａ）式に示すように、改質反応で生成された水素が、固体電解質１１３から供給される酸化物イオンと反応して水蒸気と電子を生成する。そして燃料極１１２で生成された電子が導電性フェルト１１５と導電性チューブ１１１を経て陰極１１８から外部回路に回り、陽極１１９を経て空気極１１４に到達すると、この空気極１１４において、化２（ｂ）式に示すように空気１１７中の酸素と反応して酸化物イオンを生成し、これが固体電解質１１３に放出され、燃料極１１２側に到達して化２（ａ）式の反応に供されるのである。
【０００６】
このような発電機構の円筒固体電解質型燃料電池１１０において、空気極１１４、固体電解質１１３及び燃料極１１２の部分は、従来、次にようにして形成していた。まず空気極１１４となるランタンマンガナイト系の多孔質の基体管に対して電気化学蒸着法、つまり、ＣＶＤ（ＣｈｅｍｉｃａｌＶａｐｏｒＤｅｐｏｓｉｔｉｏｎ）−ＥＶＤ（ＥｌｅｃｔｒｏｃｈｅｉｃａｌＶａｐｏｒＤｅｐｏｓｉｔｉｏｎ）法を用いて薄く、かつ緻密なＹＳＺ膜を固体電解質１１３として形成し、さらにこのＹＳＺ膜にニッケル、コバルト、ニッケル又はコバルトを主成分とする合金、あるいはニッケルジルコニアサーメットの粉末をスラリーコートし、乾燥後に焼成して多孔質の燃料極１１２を成膜するのである。
【０００７】
【発明が解決しようとする課題】
ところが、このような従来の燃料電池材料の成膜方法では、特に固体電解質の成膜方法には電気化学蒸着法を用いていたために成膜に時間がかかり、かつ装置、原料など設備及び製造コストが高くなる問題点があった。
【０００８】
また従来、燃料極の成膜方法についてはスラリーコートによって燃料極材料スラリーを基体管の内周面に塗布し、乾燥させた後に所定の高温度環境下に焼成する方法を用いていたのであるが、スラリーコートする場合には、比較的粘度の低いスラリーを基体管内周に噴霧して塗布するか、若しくは比較的粘度の高いスラリーを排泥鋳込み法で基体管内周に所定の膜厚に塗布する方法を用いていたが、燃料電池材料スラリーを噴霧して基体管の内周面に塗布する方法では、基体管が長い場合や細い場合に、その内部に噴霧管を差し込むことが困難となり、また排泥鋳込み法によって燃料極材料スラリーを基体管の内周面に塗布する場合には必要な場所だけに塗布することが難しい問題点があった。
【０００９】
本発明はこのような従来の問題点に鑑みてなされたもので、設備コストが低くでき、しかも管内径が小さくても基体管の内周面の所望の位置に固体電解質材料スラリーや燃料極材料スラリーを確実に、かつ所定の膜厚で塗布することができ、したがって均一な膜厚の固体電解質や燃料極を成膜することができる燃料電池材料塗布装置、燃料電池材料の塗布方法およびそれを用いた燃料電池材料の成膜方法を提供することを目的とする。
【００１０】
【課題を解決するための手段】
請求項１の発明の燃料電池材料塗布装置は、基体管を保持する基体管保持手段と、前記基体管保持手段に保持される基体管に軸方向に移動自在に挿入されるスラリー供給管と、前記スラリー供給管に内挿され、当該スラリー供給管に供給される燃料電池材料スラリーを回転によって前方へ均一に押出すと共に当該スラリーを基体管内に押出しつつ、当該スラリー供給管と共に前記軸方向に移動可能なスリクュー棒と、前記スクリュー棒の先端に取り付けたゴム弾性を有するラッパ状のスクレーパとを有し、前記スラリー供給管から押し出される前記燃料電池材料スラリーを前記基体管の内壁と前記スクレーパとの間隙に充填し、当該スクレーパ及び当該スラリー供給管を長手方向に移動してに所定膜厚になすり付けるものとを備えたものである。
【００１１】
請求項１の発明の燃料電池材料塗布装置では、基体管保持手段で基体管を保持し、回転するスリクュー棒が内挿されたスラリー供給管を基体管内に挿入して、燃料電池材料スラリーをスクリュー棒の回転によって前方に均一に押し出すようにして基体管内に押し出しつつ、当該スラリー供給管を基体管の長手方向に移動させ、スクリュー棒の先端に取り付けたゴム弾性を有するラッパ状のスクレーパによって、スラリー供給管から押し出され、当該スクレーパと当該基体管とがなす間隙に充填された燃料電池材料スラリーを基体管の内壁に所定膜厚になすり付け、燃料電池材料塗膜を形成する。
【００１２】
請求項２の発明の燃料電池材料の塗布方法は、基体管を保持し、回転するスリクュー棒が内挿されたスラリー供給管を前記基体管内に挿入して、固体電解質材料スラリーを前記スクリュー棒の回転によって前方に均一に押し出すようにして前記基体管内に押し出しつつ、当該スラリー供給管を前記基体管の長手方向に移動させ、前記スクリュー棒の先端に取り付けたゴム弾性を有するラッパ状のスクレーパによって、前記スラリー供給管から押し出され、当該スクレーパと当該基体管とがなす間隙に充填された前記固体電解質材料スラリーを前記基体管の内壁に所定膜厚になすり付けることを特徴とするものである。
【００１３】
請求項２の発明の燃料電池材料の塗布方法では、基体管内にスラリー供給管からスクリュー棒の回転によって押し出される固体電解質材料スラリーをゴム弾性を有するラッパ状のスクレーパによって基体管の内壁になすり付けながらこのスクレーパをスラリー供給管、スクリュー棒と共に移動することにより、スクレーパの柔軟性によって基体管の内周面各部に均一に材料スラリーをなすり付けながら移動し、均一な膜厚で固体電解質材料スラリーの塗膜を形成する。また、基体管の長手方向の所望の位置だけに限定して材料塗膜を形成する場合には、スラリー供給管から材料スラリーを押し出す位置を調整する。さらに、スラリー供給管に供給する材料スラリーはスクリュー棒で押し出すことができる粘度の比較的高いものを用いることにより、基体管の内周面に塗布された材料スラリーが自重で移動することがなく、固体電解質材料の塗膜厚を正確に調整することができる。
【００１４】
請求項３の発明の燃料電池材料の成膜方法は、請求項２の燃料電池材料の塗布方法によって前記基体管内に塗布された固体電解質材料スラリーを乾燥させ、所定の焼成温度によって前記固体電解質材料膜を焼成して固体電解質を成膜することを特徴とするものである。
【００１５】
請求項４の発明の燃料電池材料の塗布方法は、基体管を保持し、回転するスリクュー棒が内挿されたスラリー供給管を前記基体管内に挿入して、燃料極材料スラリーを前記スクリュー棒の回転によって前方に均一に押し出すようにして前記基体管内に押し出しつつ、当該スラリー供給管を前記基体管の長手方向に移動させ、前記スクリュー棒の先端に取り付けたゴム弾性を有するラッパ状のスクレーパによって、前記スラリー供給管から押し出され、当該スクレーパと当該基体管とがなす間隙に充填された前記燃料極材料スラリーを前記基体管の内壁に所定膜厚になすり付けることを特徴とするものである。
【００１６】
請求項４の発明の燃料電池材料の塗布方法では、基体管内にスラリー供給管からスクリュー棒の回転によって押し出される燃料極材料スラリーをゴム弾性を有するスクレーパによって基体管の内壁になすり付けながらこのスクレーパをスラリー供給管、スクリュー棒と共に移動することにより、スクレーパによって基体管の内周面各部に均一な圧力で材料スラリーをなすり付けながら移動し、均一な膜厚で燃料極材料スラリーの塗膜を形成する。また基体管の長手方向の所望の位置だけに限定して材料塗膜を形成する場合には、スラリー供給管から材料スラリーを押し出す位置を調整する。さらに、スラリー供給管に供給する材料スラリーはスクリュー棒で押し出すことができる粘度の比較的高いものを用いることにより、基体管の内周面に塗布された材料スラリーが自重で移動することがなく、燃料極材料の塗膜厚を正確に調整することができる。
【００１７】
請求項５の発明の燃料電池材料の成膜方法は、請求項４の燃料電池材料の塗布方法によって前記基体管内に塗布された燃料極材料スラリーを乾燥させ、所定の焼成温度によって前記燃料極材料膜を焼成して燃料極を成膜することを特徴とするものである。
【００１８】
請求項６の発明の燃料電池材料の成膜方法は、固体電解質組成から燃料極組成に段階的に変化する複数種の組成の材料スラリーを用意し、当該複数種の組成の材料スラリーを前記固体電解質組成から燃料極組成に至る順に１種類ずつ選択し、基体管を保持し、回転するスリクュー棒が内挿されたスラリー供給管を前記基体管内に挿入して、前記選択された材料スラリーを前記スクリュー棒の回転によって前方に均一に押し出すようにして前記基体管内に押し出しつつ、当該スラリー供給管を前記基体管の長手方向に移動させ、前記スクリュー棒の先端に取り付けたゴム弾性を有するラッパ状のスクレーパによって、前記スラリー供給管から押し出され、スクレーパと基体管の間隙に充填された前記選択された材料スラリーを前記基体管の内壁に所定膜厚になすり付けて塗布して前記複数種の組成の材料スラリーの塗膜を順次形成し、前記複数種の組成による複数層の塗膜を同時に焼成して前記基体管の内周面に固体電解質組成から燃料極組成に至る傾斜化された組成の材料膜を成膜することを特徴とするものである。
【００１９】
請求項６の発明の燃料電池材料の成膜方法では、固体電解質組成から燃料極組成に段階的に変化する複数種の組成の材料スラリーを用意し、基体管内に挿入したスラリー供給管から回転するスクリュー棒によって選択された材料スラリーを基体管内に押し出しつつ、ゴム弾性を有するスクレーパによって材料スラリーを基体管の内壁に所定膜厚になすり付けて塗布する工程を複数種の組成の材料スラリーそれぞれについて繰り返すことによって、固体電解質組成から燃料極組成に至る傾斜化した組成の塗膜を基体管の内周面に均一厚に形成することができる。このために、この後の焼成工程によって固体電解質組成から燃料極組成に至る傾斜化された組成の材料膜を均一厚に成膜することができる。
【００２０】
【発明の実施の形態】
以下、本発明の実施の形態を図に基づいて詳説する。
【００２１】
＜固体電解質材料の塗布方法及び固体電解質の成膜方法の実施の形態＞
第１の実施の形態は、基体管の内周面に固体電解質材料を所定膜厚に塗布し、さらに焼成することによって固体電解質を成膜する方法である。
【００２２】
基体管１０は、ストロンチウム添加ランタンマンガナイト（ＬＳＭ）製、円筒体の多孔質空気極であり、この基体管１０の寸法は特に制限されるものではないが、固体電解質型燃料電池用として、以下では外形２１ｍｍφ、内径１７ｍｍφ、長さ０．５〜１ｍのものを用いた場合について説明する。
【００２３】
固体電解質材料スラリーは、粒径０．１μｍ〜１．０μｍのＹＳＺ粉末とエタノールのような希釈剤とを混合したものである。その混合割合は１０〜４０ｗｔ％程度で、１，０００〜２，０００，０００ｍＰａＳの粘度があるものが好ましい。
【００２４】
図１に示すように、基体管１０を水平若しくは垂直に保持し、内部のスラリー供給管１１と先端に硬質ゴム製のラッパ状のスクレーパ１２が取り付けられているスクリュー棒１３との二重管を基体管１０の奥の方の所定の深さまで挿入する。そしてスラリー供給口１４から上記の固体電解質スラリー１５を供給しつつスクリュー棒１３を所定の回転数で回転させる。これによってスラリー供給管１１内に供給される固体電解質材料スラリー１５はスクリュー棒１３の回転によって前方（基体管１０の奥の方）へ押し込まれ、先端開口部からスクレーパ１２の後ろ側に押し出されるようになる。
【００２５】
この状態になれば、引き続きスラリー供給管１１内に固体電解質スラリー１５を供給しつつスクリュー棒１３を回転させ、これらのスラリー供給管１１とスクリュー棒１２を共に基体管１０から引き抜く方向に所定の速度で移動させる。
【００２６】
これによってスクレーパ１２は基体管１０内に押し出された固体電解質材料スラリー１５を基体管１０の内周面になすり付けながら移動し、固体電解質材料スラリー１５の均一な厚さの塗膜１６を形成しながら移動する。この固体電解質材料スラリー１５の塗布は、基体管１０の内周面のほぼ全面が１００〜１５０μｍの層厚になるように行う。
【００２７】
スクレーパ１２の外径は、スクレーパ１２の形状、肉厚、ゴム弾性の強さ、回転速度、移動速度、また基体管１０の内径、固体電解質スラリー１５の粘度、さらには形成しようとする塗膜厚との関係によって実験的に決定されるものであるが、例示すれば、スクレーパ１２が最大径１６．６ｍｍφ、スラリー濃度２０ｗｔ％、供給量０．３ｇ／ｓｅｃで、移動速度を５ｃｍ／ｓｅｃと設定することによって、上記１７ｍｍφの基体管１０の内周面に約１５０μｍの膜厚の塗膜を形成することができる。
【００２８】
このようにして基体管１０の内周面に塗布した固体電解質材料塗膜１６は、ゴム弾性を有するスクレーパ１２が基体管１０の内周面の全体に均一な圧力で接触しながら固体電解質材料スラリー１５を基体管１０の内周面になすり付けるようにして塗布したものなので、均一な膜厚の塗膜となる。
【００２９】
固体電解質材料スラリー１５を所定の膜厚に塗布した後には、塗膜１６を乾燥させ、さらに従来から行われている焼成を行うことによって、図２に示すように固体電解質材料塗膜１６を緻密な固体電解質膜１７に成膜する。この焼成条件は特に限定されないが、約１０００〜１６００℃、約１〜１０時間で行う。
【００３０】
こうして基体管１０の内周面に形成された固体電解質膜１７は、基体管１０の内周面にスクレーパ１２の移動によって固体電解質材料スラリー１５をなすり付けるように塗布することによって基体管１０の内周面に材料塗膜１６を均一な膜厚に密着させ、その後に乾燥し、焼成することによって成膜したものであるので、膜厚が均一で基体管１０との密着性も良好なものとなる。
【００３１】
＜燃料極材料の塗布方法及び燃料極の成膜方法の実施の形態＞
第２の実施の形態は、空気極とその内周面にすでに固体電解質が成膜されている基体管１０に対して、その内周面に燃料極材料スラリーを所定の膜厚で塗布し、さらに乾燥後に焼成して燃料極を成膜する方法である。
【００３２】
基体管１０は、従来例で説明したのと同様に、ストロンチウム添加ランタンマンガナイト（ＬＳＭ）製、円筒体の多孔質空気極１の内周面に、イットリア安定化ジルコニア（ＹＳＺ）製の緻密な固体電解質２をスラリーコーティング法、ＣＶＤ−ＥＶＤ法、あるいは上記した成膜方法によって形成したものを用いる（図３に示すように、空気極１と固体電解質２とで基体管１０とする）。この基体管１０の寸法は特に制限されるものではないが、固体電解質型燃料電池用として、以下では外形２１ｍｍφ、内径１７ｍｍφ、長さ０．５〜１ｍのものを用いた場合について説明する。
【００３３】
燃料極材料スラリーは、ニッケル（Ｎｉ）粉末、コバルト（Ｃｏ）粉末、酸化ニッケル（ＮｉＯ）粉末、酸化コバルト（ＣｏＯ）粉末、あるいはニッケルジルコニアサーメット粉末とＹＳＺ粉末とを６０ｗｔ％：４０ｗｔ％の割合で混合した混合粉末と、セルロース系バインダのような希釈剤とを混合したものである。その混合割合は５０ｗｔ％で、１，０００〜２，０００，０００ｍＰａＳの粘度のものが好ましい。
【００３４】
使用する塗布装置は、第１の実施の形態と同じく図１に示したものである。ただし、この第２の実施の形態の場合、基体管１０としては、空気極１と共に固体電解質２がその内周に成膜されているものが用いられる点、第１の実施の形態の基体管とは異なっている。燃料極材料スラリー１５の塗布工程では、基体管１０の内周面のほぼ全面が１５０μｍの膜厚の塗膜１６を形成する。
【００３５】
スクレーパ１２の外径、移動速度は第１の実施の形態と同様に、燃料極材料スラリーの粘度、供給量等によって実験的に決定するものであるが、例示すれば、第１の実施の形態と同じ条件で、１５０〜２５０μｍの燃料極材料塗膜１６を基体管１０の内周面に塗布することができる。
【００３６】
所定の膜厚に燃料極材料スラリー１５を塗布して燃料極材料塗膜１６を形成した後、第１の実施の形態と同様に塗膜１６を乾燥させ、さらに焼成することによって、図３に示すように基体管１０の固体電解質２の内周面にサーメット化した多孔質の燃料極１８を成膜する。この焼成条件は特に限定されないが、約１０００〜１４００℃、約１〜１０時間で行う。
【００３７】
こうして基体管１０の内周面に成膜された燃料極１８は、基体管１０の内周面にスクレーパ１２の移動によって燃料極材料スラリー１５をなすり付けるように塗布することによって基体管１０の内周面に材料塗膜１６を均一な膜厚に密着させ、その後に乾燥し、焼成することによって成膜したものであるので、膜厚が均一で基体管１０との密着性も良好なものとなる。
【００３８】
＜固体電解質材料と燃料極材料との塗布方法及び固体電解質と燃料極との成膜方法＞
第３の実施の形態は、第１の実施の形態で説明した固体電解質材料の塗布方法を用いて基体管をなす空気極の内周面に固体電解質材料を塗布し、さらにこの固体電解質塗膜の内周面に第２の実施の形態で説明した燃料極材料の塗布方法を用いて燃料極材料を塗布し、これらを同時に焼成して成膜することを特徴とする。すなわち、図４（ａ）に示すように、第１の実施の形態の固体電解質材料の塗布方法を使用して基体管１０である空気極の内周面にまず固体電解質塗膜１６ａを塗布して乾燥させ、さらに同図（ｂ）に示すように、第２の実施の形態の燃料極材料の塗布方法を使用して、固体電解質塗膜１６ａの内周面に燃料極塗膜１６ｂを塗布する。なお、基体管１０の寸法、材料組成、成膜条件等はすべて第１の実施の形態、第２の実施の形態と共通する。
【００３９】
これら両材料の塗膜１６ａ，１６ｂを塗布形成した後、第１の実施の形態と同様の焼成条件で焼成することによって基体管１０である空気極の内側に固体電解質と燃料極が成膜された円筒固体電解質型燃料電池を得る。
【００４０】
この第３の実施の形態の固体電解質材料及び燃料極材料塗布方法、及び固体電解質及び燃料極の成膜方法によれば、固体電解質と燃料極とを共にスラリーコーティング方法によって成膜するので、従来の電気化学蒸着法による成膜方法よりも製造時間を短縮することができ、かつ第１の実施の形態、第２の実施の形態と同様の効果も期待できる。
【００４１】
なお、この第３の実施の形態の場合、基体管１０の内周面に固体電解質材料の塗膜１６ａを塗布し、乾燥させた後に焼成してまず固体電解質膜を成膜し、その後、この固体電解質膜上に燃料極材料の塗膜１６ｂを塗布し、乾燥させた後に焼成して燃料極を成膜する手順を採用することもできる。
【００４２】
次に、第４の実施の形態の燃料電池材料の塗布方法及び燃料電池材料の成膜方法について説明する。この第４の実施の形態の特徴は、空気極で成る基体管１０の内周面に固体電解質組成から燃料極組成に至る傾斜化させた組成の材料スラリー層を複数層に塗布し、さらに焼成することによって固体電解質組成から燃料極組成に至る傾斜化した傾斜組成膜１８を同時に成膜する点にある。以下、この塗布方法及び成膜方法について、図５に基づいて説明する。
【００４３】
基体管１０には第１の実施の形態と同一の空気極をなす基体管を用いる。そして図１に示した装置によって基体管１０の内周面に第１の実施の形態と同じ固体電解質の組成に調製された固体電解質材料スラリーを塗布して固体電解質材料組成の塗膜２１ａを形成し、乾燥させる（図５（ａ）参照）。
【００４４】
続いて、固体電解質組成と燃料極組成との中間組成で、ニッケル（Ｎｉ）粉末、コバルト（Ｃｏ）粉末、酸化ニッケル（ＮｉＯ）粉末、酸化コバルト（ＣｏＯ）粉末、あるいはニッケルジルコニアサーメット粉末とＹＳＺ粉末とを６０ｗｔ％：４０ｗｔ％の割合で混合した混合粉末と、セルロース系バインダのような希釈剤とを混合したスラリーであり、５０ｗｔ％程度の混合割合のものを用いる。そしてこの中間組成の材料スラリーを図１に示した装置によって固体電解質材料塗膜２１ａの内周面に塗布して中間組成材料塗膜２１ｂを形成し、乾燥させる（図５（ｂ）参照）。
【００４５】
次に、第２の実施の形態で用いた燃料極組成のスラリーを用いて、図１に示した装置によって中間組成材料塗膜２１ｂの内周面に塗布して燃料極材料塗膜２１ｃを形成して乾燥させる（図５（ｃ）参照）。
【００４６】
この後、これらの固体電解質材料組成〜燃料極材料間の傾斜化した組成の材料塗膜２１ａ〜２１ｃが形成された基体管１０に対して、第１の実施の形態と同様の条件で焼成を行うことによって、図６に示すように基体管１０の内周面に固体電解質組成から燃料極組成に至る傾斜化した組成の傾斜組成膜２２を形成することができる。
【００４７】
こうして基体管１０の内周面に成膜した固体電解質組成から燃料極組成に至る傾斜組成膜２２は、基体管１０の内周面に複数種の組成の材料スラリーをスクレーパ１２によって順次塗布して塗膜２１ａ〜２１ｃを形成し、焼成することによって形成されたものであるので、第１〜第３の実施の形態と同様の効果を期待することができ、その結果、傾斜組成膜２２も膜厚が均一で基体管１０との密着性も良好なものとなる。また固体電解質と燃料極とを同じ成膜工程で成膜するので、製造工程の簡略化、成膜時間の短縮化が図れる。
【００４８】
【実施例】
（実施例１）
空気極となる外径２１ｍｍφ、内径１７ｍｍφ、長さ５０ｃｍであるＬＳＭ製の基体管を水平に保持し、内部に１４ｍｍφのスラリー供給管とスクリュー棒を挿入した。スクリュー棒の先端には、外径１６．６ｍｍφの硬質ゴム製のラップ状のスクレーパが取り付けてある。そして、ＹＳＺ粉末２０ｗｔ％をエタノール希釈剤とアクリル系バインダに混合した粘度１００，０００ｍＰａ・ｓの固体電解質材料スラリーをスラリー供給管に０．３ｇ／ｓｅｃの割合で供給し、スクリュー棒を回転させることによって基体管内に押し出しつつ、５ｃｍ／ｓｅｃの速度でゆっくりと引き抜いていった。
【００４９】
内部に形成された固体電解質材料塗膜を観察したが、膜厚は１５０μｍで基体管の内周面に均一に塗布されていた。
【００５０】
続いて、この基体管を焼成炉に入れて焼成した。焼成条件は１５００℃、１０時間であった。この結果、基体管の内周面に成膜された固体電解質膜は、７０μｍの均一な膜厚であった。
【００５１】
（実施例２）
空気極となる外径２１ｍｍφのＬＳＭ管の内周面に固体電解質となるＹＳＺ膜が成膜されていて、外径２１ｍｍφ、内径１７ｍｍφ、長さ５０ｃｍである基体管を水平に保持し、内部に実施例１と同じスラリー供給管とスクリュー棒を挿入した。そして、Ｎｉ粉末６０ｗｔ％：ＹＳＺ粉末４０ｗｔ％の混合粉末をセルロース系バインダと６０ｗｔ％：４０ｗｔ％の割合で混合した粘度１０，０００ｍＰａ・ｓの燃料極材料スラリーをスラリー供給管に０．５ｇ／ｓｅｃの割合で供給し、スクリュー棒を回転させて基体管内に材料スラリーを押し出しつつ、３ｃｍ／ｓｅｃの速度でゆっくりと引き抜いていった。
【００５２】
内部に形成された燃料極材料層塗膜を観察したが、膜厚は１７０μｍで均一に塗布されていた。
【００５３】
続いて、この基体管を焼成炉に入れて焼成した。焼成条件は実施例１と同じであった。この結果、基体管の内周面に成膜された燃料極膜は、７０μｍの均一な膜厚であった。
【００５４】
（実施例３）
実施例１と同じ仕様の基体管の内周面に対して、ＹＳＺ粉末１０〜４０ｗｔ％をアクリル系バインダに混合した粘度１００，０００ｍＰａ・ｓの固体電解質材料スラリーを実施例１と同じ条件で塗布し、１００μｍの固体電解質材料塗膜２１ａを形成し、乾燥させた。
【００５５】
続いて、この固体電解質材料塗膜２１ａの内周面に対して、ニッケル（Ｎｉ）粉末とＹＳＺ粉末とを５０ｗｔ％：５０ｗｔ％の割合で混合した混合粉末と、セルロース系バインダの希釈剤とを１：１の割合で混合した、粘度５，０００ｍＰａ・ｓの固体電解質組成と燃料極組成との中間組成のスラリーを用い、固体電解質材料スラリーの場合と同じ条件で塗布して８０μｍの固体電解質と燃料極との中間組成の材料塗膜２１ｂを形成し、乾燥させた。
【００５６】
さらに、この中間組成の材料塗膜２１ｂの内周面に対して、実施例２と同じ組成の燃料極材料スラリーを実施例２と同じ条件で塗布して８０μｍの燃料極材料塗膜２１ｃを形成し、乾燥させた。
【００５７】
この後、３層の材料塗膜２１ａ〜２１ｃが形成された基体管１０を焼成炉に入れて焼成した。焼成条件は１４００℃、５時間であった。この結果、基体管の内周面に固体電解質組成から燃料極組成に至るまで組成が傾斜した傾斜組成膜２２を形成することができ、その膜厚は全体で６０μｍの均一なものであった。
【００５８】
【発明の効果】
以上のように請求項１の発明の燃料電池材料塗布装置によれば、基体管保持手段で基体管を保持し、回転するスリクュー棒が内挿されたスラリー供給管を基体管内に挿入して、燃料電池材料スラリーをスクリュー棒の回転によって前方に均一に押し出すようにして基体管内に押し出しつつ、当該スラリー供給管を基体管の長手方向に移動させ、スクリュー棒の先端に取り付けたゴム弾性を有するラッパ状のスクレーパによって、スラリー供給管から押し出され、スクレーパと基体管とがなす間隙に充填された燃料電池材料スラリーを基体管の内壁に所定膜厚になすり付け、燃料電池材料塗膜を形成するので、スクレーパの柔軟性によって基体管の内周面各部に均一な膜厚で燃料電池材料スラリーの塗膜を形成することができ、また、スラリー供給管から材料スラリーを押し出す位置を調整することによって基体管の長手方向の所望の位置だけに限定して材料塗膜を形成することができ、さらに、スラリー供給管に供給する材料スラリーはスクリュー棒で押し出すことができる粘度の比較的高いものを用いることができ、基体管の内周面に塗布された材料スラリーが自重で移動することがなく、燃料電池材料の塗膜厚を正確に調整することができる。
【００５９】
請求項２の発明の燃料電池材料の塗布方法によれば、基体管内にスラリー供給管からスクリュー棒の回転によって前方に均一に押し出され、ゴム弾性を有するスクレーパと基体管とがなす間隙に充填された固体電解質材料スラリーをラッパ状のスクレーパによって基体管の内壁になすり付けながらこのスクレーパをスラリー供給管、スクリュー棒と共に移動するので、スクレーパの柔軟性によって基体管の内周面各部に均一に材料スラリーをなすり付けながら移動し、均一な膜厚で固体電解質材料スラリーの塗膜を形成することができる。
また、スラリー供給管から材料スラリーを押し出す位置を調整することによって基体管の長手方向の所望の位置だけに限定して材料塗膜を形成することができる。さらに、スラリー供給管に供給する材料スラリーはスクリュー棒で押し出すことができる粘度の比較的高いものを用いることができ、基体管の内周面に塗布された材料スラリーが自重で移動することがなく、固体電解質材料の塗膜厚を正確に調整することができる。
【００６０】
請求項３の発明の燃料電池材料の成膜方法によれば、請求項２の燃料電池材料の塗布方法によって基体管内に塗布された固体電解質材料スラリーを乾燥させ、所定の焼成温度によって固体電解質材料膜を焼成して固体電解質を成膜するので、均一な膜厚の固体電解質を容易に成膜することができる。
【００６１】
請求項４の発明の燃料電池材料の塗布方法によれば、基体管内にスラリー供給管からスクリュー棒の回転によって前方に均一に押し出され、ゴム弾性を有するスクレーパと基体管とがなす間隙に充填された燃料極材料スラリーをこのスクレーパによって基体管の内壁になすり付けながらこのスクレーパをスラリー供給管、スクリュー棒と共に移動するので、スクレーパによって基体管の内周面各部に均一な圧力で材料スラリーをなすり付けながら移動し、均一な膜厚で燃料極材料スラリーの塗膜を形成することができる。またスラリー供給管から材料スラリーを押し出す位置を調整することによって、基体管の長手方向の所望の位置だけに限定して材料塗膜を形成することができる。さらに、スラリー供給管に供給する材料スラリーはスクリュー棒で押し出すことができる粘度の比較的高いものを用いることができ、基体管の内周面に塗布された材料スラリーが自重で移動することがなく、燃料極材料の塗膜厚を正確に調整することができる。
【００６２】
請求項５の発明の燃料電池材料の成膜方法によれば、請求項４の燃料電池材料の塗布方法によって基体管内に塗布された燃料極材料スラリーを乾燥させ、所定の焼成温度によって前記燃料極材料膜を焼成して燃料極を成膜するので、均一な膜厚の燃料極を容易に成膜することができる。
【００６３】
請求項６の発明の燃料電池材料の成膜方法によれば、固体電解質組成から燃料極組成に段階的に変化する複数種の組成の材料スラリーを用意し、基体管内に挿入したスラリー供給管から回転するスクリュー棒によって、選択された材料スラリーを基体管内に押し出しつつ、ゴム弾性を有するスクレーパと基体管とがなす間隙に充填し、このスクレーパによって材料スラリーを基体管の内壁に所定膜厚になすり付けて塗布する工程を複数種の組成の材料スラリーそれぞれについて繰り返すことによって、固体電解質組成から燃料極組成に至る傾斜化した組成の塗膜を基体管の内周面に均一厚に形成することができ、この後の焼成工程によって固体電解質組成から燃料極組成に至る傾斜化された組成の材料膜を均一厚に成膜することができる。
【図面の簡単な説明】
【図１】本発明の燃料電池材料の塗布方法に用いる塗布装置の断面図。
【図２】本発明の第１の実施の形態の燃料電池材料の塗布方法によって固体電解質材料を基体管の内周面に塗布した状態を示す断面図。
【図３】本発明の第２の実施の形態の燃料電池材料の塗布方法によって燃料極材料を基体管の内周面に塗布した状態を示す断面図。
【図４】本発明の第３の実施の形態の燃料電池材料の塗布方法によって固体電解質材料と燃料極材料とを基体管の内周面に塗布した状態を示す断面図。
【図５】本発明の第４の実施の形態の燃料電池材料の成膜方法において３種の傾斜組成材料塗膜を塗布した状態の断面図。
【図６】上記の第４の実施の形態の燃料電池材料の成膜方法で成膜した燃料電池セルの断面図。
【図７】一般的な円筒固体電解質型燃料電池の構造を示す断面図。
【符号の説明】
１空気極
２固体電解質
１０基体管
１１スラリー供給管
１２スクレーパ
１３スクリュー棒
１４スラリー供給口
１５燃料電池材料スラリー
１６，１６ａ，１６ｂ塗膜
１７固体電解質
１８燃料極
２１ａ，２１ｂ，２１ｃ塗膜
２２傾斜組成膜[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fuel cell material coating device, a fuel cell material coating method, and a fuel cell material film forming method using the same.
[0002]
[Prior art]
Conventionally, as a solid electrolyte fuel cell of a cylindrical vertical stripe type, for example, a solid electrolyte fuel cell 110 described in Japanese Patent Application Laid-Open No. Hei 7-263001 and having a structure shown in FIG. 7 has been proposed. This conventional solid oxide fuel cell 110 is characterized by a structure in which a conductive tube 111 for fuel supply is inserted at the center, and a fuel electrode 112, a solid electrolyte 113, and an air electrode 114 are formed in this order from the inside, and A conductive tube 111 for supplying fuel, which is made porous for fuel ejection, is filled with a conductive felt 115 having a fuel reforming function between the conductive tube 111 and the fuel electrode 112; The fuel gas 116 is supplied to the conductive tube 111, and the air 117 flows around the outer periphery.
[0003]
The power generation operation of the solid oxide fuel cell 110 will be described. A fuel gas 116 such as natural gas, methane, or coal gasification gas is supplied into the conductive tube 111 of the battery 110, and a porous tube of the conductive tube 111 is formed. Under the condition of high temperature conditions, usually 650 ° C. to 1050 ° C., the conductive felt 115, the fuel electrode 112 and the solid electrolyte 113 are spouted out through the wall onto the conductive felt 115. Causes a reforming reaction.
[0004]
Embedded image

With respect to hydrogen generated by the reforming reaction, a power generation reaction represented by the following formula 2 is caused in a portion between the fuel electrode 112 and the air electrode 114 which are opposed to each other via the solid electrolyte 113, and the released electrons are collected. To generate power.
[0005]
Embedded image

That is, in the fuel electrode 112, as shown in Formula 2 (a), hydrogen generated by the reforming reaction reacts with oxide ions supplied from the solid electrolyte 113 to generate water vapor and electrons. Then, the electrons generated at the fuel electrode 112 travel from the cathode 118 to the external circuit via the conductive felt 115 and the conductive tube 111, and reach the air electrode 114 via the anode 119. As shown in the formula (1), it reacts with oxygen in the air 117 to generate oxide ions, which are released to the solid electrolyte 113, reach the fuel electrode 112 side, and are subjected to the reaction of formula (2). It is.
[0006]
In the cylindrical solid oxide fuel cell 110 having such a power generation mechanism, the air electrode 114, the solid electrolyte 113, and the fuel electrode 112 are conventionally formed as follows. First, a thin and dense YSZ film is formed on a lanthanum manganite-based porous base tube serving as the air electrode 114 by an electrochemical deposition method, that is, a CVD (Chemical Vapor Deposition) -EVD (Electrochemical Vapor Deposition) method. Is formed as a solid electrolyte 113. Further, the YSZ film is slurry-coated with nickel, cobalt, an alloy containing nickel or cobalt as a main component, or nickel zirconia cermet powder, dried and fired to form a porous fuel electrode 112. The film is formed.
[0007]
[Problems to be solved by the invention]
However, in such a conventional method for forming a film of a fuel cell material, since a method for forming a solid electrolyte is formed by an electrochemical deposition method, it takes a long time to form a film, and equipment and raw materials such as an apparatus, a raw material, and a manufacturing cost are reduced. There was a problem that becomes high.
[0008]
Conventionally, as a method of forming a fuel electrode, a method has been used in which a fuel electrode material slurry is applied to the inner peripheral surface of a base tube by slurry coating, dried, and then fired under a predetermined high temperature environment. In the case of slurry coating, a slurry having a relatively low viscosity is sprayed and applied to the inner periphery of the base tube, or a slurry having a relatively high viscosity is applied to the inner periphery of the base tube by a mud casting method to a predetermined thickness. However, in the method of spraying the fuel cell material slurry and applying the slurry to the inner peripheral surface of the base tube, when the base tube is long or thin, it is difficult to insert the spray tube into the inside, When the anode material slurry is applied to the inner peripheral surface of the base tube by the sludge casting method, there is a problem that it is difficult to apply the slurry only to a necessary place.
[0009]
The present invention has been made in view of such conventional problems, and can reduce the equipment cost, and even when the inside diameter of the tube is small, the solid electrolyte material slurry or the fuel electrode material can be placed at a desired position on the inner peripheral surface of the base tube. A fuel cell material coating apparatus, a method for coating a fuel cell material, and a method for coating a slurry with certainty and a predetermined film thickness, thereby forming a solid electrolyte or a fuel electrode with a uniform film thickness. An object of the present invention is to provide a method for forming a film of a fuel cell material used.
[0010]
[Means for Solving the Problems]
The fuel cell material coating apparatus according to the first aspect of the present invention includes: a base tube holding means for holding a base tube; a slurry supply tube axially movably inserted into the base tube held by the base tube holding means; The fuel cell material slurry inserted into the slurry supply pipe and supplied to the slurry supply pipe is rotated forward. Uniformly With extrusion While extruding the slurry into the base tube A slipper rod movable in the axial direction together with the slurry supply pipe, and a rubber-elastic trumpet-shaped scraper attached to a tip of the screw rod. And have The slurry of the fuel cell material extruded from the slurry supply pipe is placed on the inner wall of the base pipe. And the gap between the scraper and the scraper and the slurry supply pipe are moved in the longitudinal direction. And a part to be rubbed to a predetermined film thickness.
[0011]
In the fuel cell material coating apparatus according to the first aspect of the present invention, the base tube is held by the base tube holding means, and the slurry supply tube in which the rotating screw rod is inserted is inserted into the base tube, and the fuel cell material slurry is screwed. Forward by the rotation of the rod Uniformly While extruding into the base tube as it is extruded, the slurry supply tube is moved in the longitudinal direction of the base tube, and is extruded from the slurry supply tube by a rubber elastic trumpet-shaped scraper attached to the tip of the screw rod, Filled in the gap between the scraper and the base tube The fuel cell material slurry is rubbed to the inner wall of the base tube to a predetermined thickness to form a fuel cell material coating.
[0012]
In the method for applying a fuel cell material according to the second aspect of the present invention, a slurry supply pipe in which a rotating screw rod is inserted is inserted into the base pipe while holding a base pipe, and a solid electrolyte material slurry is supplied to the screw rod by the screw rod. Forward by rotation Uniformly The slurry supply tube was moved in the longitudinal direction of the substrate tube while being pushed out into the substrate tube in such a manner as to be extruded, and was pushed out of the slurry supply tube by a rubber elastic flapper-shaped scraper attached to the tip of the screw rod. And Filled in the gap between the scraper and the base tube The solid electrolyte material slurry is rubbed to the inner wall of the base tube to a predetermined thickness.
[0013]
In the method for applying a fuel cell material according to the second aspect of the present invention, the solid electrolyte material slurry extruded from the slurry supply pipe into the base pipe by the rotation of the screw rod is rubbed on the inner wall of the base pipe by a rubbery flared scraper. While moving the scraper together with the slurry supply pipe and the screw rod, the material slurry is moved while rubbing the material slurry uniformly on each part of the inner peripheral surface of the base tube by the flexibility of the scraper, and the solid electrolyte material slurry is formed in a uniform film thickness. To form a coating film. When the material coating is formed only at a desired position in the longitudinal direction of the base tube, the position at which the material slurry is extruded from the slurry supply tube is adjusted. Furthermore, by using a material slurry supplied to the slurry supply pipe having a relatively high viscosity that can be extruded with a screw rod, the material slurry applied to the inner peripheral surface of the base pipe does not move by its own weight, The coating thickness of the solid electrolyte material can be accurately adjusted.
[0014]
According to a third aspect of the present invention, there is provided a method for forming a fuel cell material, comprising drying the solid electrolyte material slurry applied to the inside of the base tube by the fuel cell material application method according to the second aspect, and applying the solid electrolyte material at a predetermined firing temperature. The method is characterized in that the film is fired to form a solid electrolyte.
[0015]
The method for applying a fuel cell material according to the invention of claim 4 is such that a slurry supply pipe in which a rotating screw rod is inserted is inserted into the base pipe while holding a base pipe, and a fuel electrode material slurry is supplied to the screw rod. Forward by rotation Uniformly The slurry supply tube was moved in the longitudinal direction of the substrate tube while being pushed out into the substrate tube in such a manner as to be extruded, and was pushed out of the slurry supply tube by a rubber elastic flapper-shaped scraper attached to the tip of the screw rod. And Filled in the gap between the scraper and the base tube The fuel electrode material slurry is rubbed into the inner wall of the base tube to a predetermined thickness.
[0016]
In the method for applying a fuel cell material according to the fourth aspect of the present invention, the fuel electrode material slurry extruded from the slurry supply tube into the base tube by the rotation of the screw rod is rubbed on the inner wall of the base tube by a rubber elastic scraper. Is moved together with the slurry supply pipe and the screw rod, and the scraper is used to move the material slurry while rubbing the inner peripheral surface of the base pipe with uniform pressure at a uniform pressure. Form. When the material coating is formed only at a desired position in the longitudinal direction of the base tube, the position where the material slurry is extruded from the slurry supply tube is adjusted. Furthermore, by using a material slurry supplied to the slurry supply pipe having a relatively high viscosity that can be extruded with a screw rod, the material slurry applied to the inner peripheral surface of the base pipe does not move by its own weight, The coating thickness of the fuel electrode material can be accurately adjusted.
[0017]
According to a fifth aspect of the present invention, there is provided a method for forming a fuel cell material, comprising drying the anode material slurry applied to the inside of the base tube by the fuel cell material application method according to the fourth aspect, and applying the fuel electrode material at a predetermined firing temperature. The fuel electrode is formed by firing the film.
[0018]
The method for forming a film of a fuel cell material according to the invention of claim 6 includes preparing a plurality of types of material slurries that change stepwise from a solid electrolyte composition to a fuel electrode composition, and applying the plurality of types of material slurries to the solid state. Select one kind at a time from the electrolyte composition to the fuel electrode composition, hold the base tube, insert a slurry supply tube with a rotating screw rod inserted into the base tube, and transfer the selected material slurry to the base tube. Forward by the rotation of the screw rod Uniformly The slurry supply tube was moved in the longitudinal direction of the substrate tube while being pushed out into the substrate tube in such a manner as to be extruded, and was pushed out of the slurry supply tube by a rubber elastic flapper-shaped scraper attached to the tip of the screw rod. And Filled in the gap between the scraper and the base tube The selected material slurry is applied to the inner wall of the base tube by rubbing to a predetermined thickness to form a coating of the material slurry having the plurality of types of compositions sequentially, and a plurality of layers of the coating of the plurality of types of compositions are applied. The film is simultaneously fired to form a material film having a graded composition ranging from a solid electrolyte composition to a fuel electrode composition on the inner peripheral surface of the base tube.
[0019]
In the method of forming a fuel cell material according to the invention of claim 6, a plurality of types of material slurries that change stepwise from the solid electrolyte composition to the fuel electrode composition are prepared and rotated from a slurry supply pipe inserted into the base tube. The step of extruding the material slurry selected by the screw rod into the base tube and rubbing the material slurry on the inner wall of the base tube to a predetermined thickness with a rubber elastic scraper and applying the same is performed for each of the material slurries having a plurality of compositions. By repeating this, a coating film having a gradient from the solid electrolyte composition to the fuel electrode composition can be uniformly formed on the inner peripheral surface of the base tube. Therefore, a material film having a gradient composition from the solid electrolyte composition to the fuel electrode composition can be formed to a uniform thickness by the subsequent firing step.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0021]
<Embodiments of coating method of solid electrolyte material and method of forming solid electrolyte film>
The first embodiment is a method in which a solid electrolyte material is applied to an inner peripheral surface of a base tube to a predetermined thickness, and further fired to form a solid electrolyte film.
[0022]
The base tube 10 is a cylindrical porous air electrode made of strontium-added lanthanum manganite (LSM). The dimensions of the base tube 10 are not particularly limited. In the following, a case will be described in which an outer diameter of 21 mmφ, an inner diameter of 17 mmφ, and a length of 0.5 to 1 m is used.
[0023]
The solid electrolyte material slurry is a mixture of YSZ powder having a particle size of 0.1 μm to 1.0 μm and a diluent such as ethanol. The mixing ratio is about 10 to 40% by weight, and preferably has a viscosity of 1,000 to 2,000,000 mPaS.
[0024]
As shown in FIG. 1, a base tube 10 is held horizontally or vertically, and a double tube of a slurry supply tube 11 inside and a screw rod 13 having a hard rubber flared scraper 12 attached to the tip is provided. The base tube 10 is inserted to a predetermined depth at the back. Then, the screw rod 13 is rotated at a predetermined rotation speed while the solid electrolyte slurry 15 is supplied from the slurry supply port 14. As a result, the solid electrolyte material slurry 15 supplied into the slurry supply pipe 11 is pushed forward (toward the back of the base tube 10) by the rotation of the screw rod 13, and is pushed out from the opening at the front end to the rear side of the scraper 12. become.
[0025]
In this state, the screw rod 13 is rotated while continuously supplying the solid electrolyte slurry 15 into the slurry supply pipe 11, and a predetermined speed is set in a direction in which both the slurry supply pipe 11 and the screw rod 12 are pulled out from the base pipe 10. To move.
[0026]
As a result, the scraper 12 moves while rubbing the solid electrolyte material slurry 15 extruded into the base tube 10 onto the inner peripheral surface of the base tube 10 to form a coating film 16 of the solid electrolyte material slurry 15 having a uniform thickness. While moving. The application of the solid electrolyte material slurry 15 is performed such that substantially the entire inner peripheral surface of the base tube 10 has a layer thickness of 100 to 150 μm.
[0027]
The outer diameter of the scraper 12 is determined by the shape, thickness, rubber elasticity, rotation speed, and moving speed of the scraper 12, the inner diameter of the base tube 10, the viscosity of the solid electrolyte slurry 15, and the thickness of the coating film to be formed. For example, the scraper 12 has a maximum diameter of 16.6 mmφ, a slurry concentration of 20 wt%, a supply amount of 0.3 g / sec, and a moving speed of 5 cm / sec. By doing so, a coating film having a thickness of about 150 μm can be formed on the inner peripheral surface of the base tube 10 of 17 mmφ.
[0028]
The solid electrolyte material coating film 16 applied to the inner peripheral surface of the base tube 10 in this manner is applied to the solid electrolyte material slurry while the scraper 12 having rubber elasticity contacts the entire inner peripheral surface of the base tube 10 at a uniform pressure. 15 is applied so as to be rubbed on the inner peripheral surface of the base tube 10, so that the coating film has a uniform thickness.
[0029]
After the solid electrolyte material slurry 15 is applied to a predetermined film thickness, the coating film 16 is dried and further baked in a conventional manner so that the solid electrolyte material coating film 16 becomes dense as shown in FIG. The solid electrolyte membrane 17 is formed. The firing conditions are not particularly limited, but the firing is performed at about 1000 to 1600 ° C. for about 1 to 10 hours.
[0030]
The solid electrolyte membrane 17 thus formed on the inner peripheral surface of the base tube 10 is applied to the inner peripheral surface of the base tube 10 by rubbing the solid electrolyte material slurry 15 with the movement of the scraper 12. The material coating 16 is adhered to the inner peripheral surface to a uniform film thickness, then dried and fired to form a film, so that the film thickness is uniform and the adhesion to the base tube 10 is good. It becomes.
[0031]
<Embodiment of coating method of fuel electrode material and film forming method of fuel electrode>
In the second embodiment, a fuel electrode material slurry is applied to the inner peripheral surface of the air electrode and the base tube 10 in which a solid electrolyte is already formed on the inner peripheral surface in a predetermined thickness, This is a method in which the fuel electrode is formed by firing after drying.
[0032]
The base tube 10 is made of strontium-added lanthanum manganite (LSM) and has a dense inner surface of the cylindrical porous air electrode 1 made of yttria-stabilized zirconia (YSZ), as described in the conventional example. A solid electrolyte 2 formed by a slurry coating method, a CVD-EVD method, or the above-described film forming method is used (as shown in FIG. 3, the air electrode 1 and the solid electrolyte 2 form a base tube 10). Although the dimensions of the base tube 10 are not particularly limited, a case using a solid oxide fuel cell having an outer diameter of 21 mmφ, an inner diameter of 17 mmφ, and a length of 0.5 to 1 m will be described below.
[0033]
The fuel electrode material slurry is composed of nickel (Ni) powder, cobalt (Co) powder, nickel oxide (NiO) powder, cobalt oxide (CoO) powder, or nickel zirconia cermet powder and YSZ powder at a ratio of 60 wt%: 40 wt%. It is obtained by mixing the mixed powder and a diluent such as a cellulose-based binder. The mixing ratio is 50 wt%, and a viscosity of 1,000 to 2,000,000 mPaS is preferable.
[0034]
The coating device used is the same as that of the first embodiment shown in FIG. However, in the case of the second embodiment, as the base tube 10, the one in which the solid electrolyte 2 is formed on the inner periphery thereof together with the air electrode 1 is used, and the base tube of the first embodiment is used. Is different from In the step of applying the fuel electrode material slurry 15, a coating film 16 having a thickness of 150 μm is formed on substantially the entire inner peripheral surface of the base tube 10.
[0035]
The outer diameter and the moving speed of the scraper 12 are experimentally determined based on the viscosity and supply amount of the fuel electrode material slurry, as in the first embodiment. Under the same conditions as above, a fuel electrode material coating film 16 of 150 to 250 μm can be applied to the inner peripheral surface of the base tube 10.
[0036]
After the anode electrode material slurry 15 is applied to a predetermined thickness to form the anode electrode coating film 16, the coating film 16 is dried and baked in the same manner as in the first embodiment. As shown, a porous cermet fuel electrode 18 is formed on the inner peripheral surface of the solid electrolyte 2 of the base tube 10. The firing conditions are not particularly limited, but the firing is performed at about 1000 to 1400 ° C. for about 1 to 10 hours.
[0037]
The fuel electrode 18 thus formed on the inner peripheral surface of the base tube 10 is applied to the inner peripheral surface of the base tube 10 by applying a fuel electrode material slurry 15 to the inner peripheral surface of the base tube 10 by moving the scraper 12. The material coating 16 is adhered to the inner peripheral surface to a uniform film thickness, then dried and fired to form a film, so that the film thickness is uniform and the adhesion to the base tube 10 is good. It becomes.
[0038]
<Method of coating solid electrolyte material and fuel electrode material and method of forming solid electrolyte and fuel electrode>
In the third embodiment, the solid electrolyte material is applied to the inner peripheral surface of the air electrode forming the base tube by using the method for applying the solid electrolyte material described in the first embodiment. The fuel electrode material is applied to the inner peripheral surface by using the method for applying the fuel electrode material described in the second embodiment, and these are simultaneously fired to form a film. That is, as shown in FIG. 4A, first, a solid electrolyte coating 16a is applied to the inner peripheral surface of the air electrode serving as the base tube 10 using the method for applying a solid electrolyte material of the first embodiment. Then, as shown in FIG. 2B, the anode electrode coating film 16b is applied to the inner peripheral surface of the solid electrolyte coating film 16a by using the anode electrode material application method of the second embodiment. I do. Note that the dimensions, material composition, film forming conditions, and the like of the base tube 10 are all the same as those of the first embodiment and the second embodiment.
[0039]
After the

coating films

16a and 16b of these materials are applied and formed, the solid electrolyte and the fuel electrode are formed inside the air electrode as the base tube 10 by firing under the same firing conditions as in the first embodiment. To obtain a cylindrical solid oxide fuel cell.
[0040]
According to the solid electrolyte material and fuel electrode material coating method and the solid electrolyte and fuel electrode film forming method of the third embodiment, both the solid electrolyte and the fuel electrode are formed by a slurry coating method. The manufacturing time can be shortened as compared with the film forming method by the electrochemical vapor deposition method, and the same effect as in the first embodiment and the second embodiment can be expected.
[0041]
In the case of the third embodiment, a coating 16a of a solid electrolyte material is applied to the inner peripheral surface of the base tube 10, dried and fired to form a solid electrolyte film first. It is also possible to adopt a procedure in which the coating 16b of the anode material is applied on the solid electrolyte membrane, dried, and fired to form the anode.
[0042]
Next, a method for applying a fuel cell material and a method for forming a fuel cell material according to the fourth embodiment will be described. The feature of the fourth embodiment is that a plurality of layers of a material slurry layer having a graded composition ranging from a solid electrolyte composition to a fuel electrode composition are applied to the inner peripheral surface of a base tube 10 composed of an air electrode, and then fired. Thus, a gradient composition film 18 having a gradient from the solid electrolyte composition to the fuel electrode composition is simultaneously formed. Hereinafter, the coating method and the film forming method will be described with reference to FIG.
[0043]
As the base tube 10, a base tube forming the same air electrode as in the first embodiment is used. Then, the solid electrolyte material slurry prepared to have the same solid electrolyte composition as in the first embodiment is applied to the inner peripheral surface of the base tube 10 by the apparatus shown in FIG. 1 to form a coating film 21a of the solid electrolyte material composition. And dried (see FIG. 5A).
[0044]
Subsequently, nickel (Ni) powder, cobalt (Co) powder, nickel oxide (NiO) powder, cobalt oxide (CoO) powder, or nickel zirconia cermet powder and YSZ powder in an intermediate composition between the solid electrolyte composition and the fuel electrode composition. And a slurry in which a mixed powder obtained by mixing the above components in a ratio of 60 wt%: 40 wt% and a diluent such as a cellulose-based binder are used, and a mixture having a mixing ratio of about 50 wt% is used. The material slurry having the intermediate composition is applied to the inner peripheral surface of the solid electrolyte material coating 21a by the apparatus shown in FIG. 1 to form the intermediate composition material coating 21b and dried (see FIG. 5B).
[0045]
Next, the slurry of the fuel electrode composition used in the second embodiment is applied to the inner peripheral surface of the intermediate composition material coating film 21b by the apparatus shown in FIG. 1 to form the fuel electrode material coating film 21c. And dried (see FIG. 5 (c)).
[0046]
Thereafter, firing is performed on the base tube 10 on which the material coatings 21a to 21c having the graded composition between the solid electrolyte material composition and the fuel electrode material are formed under the same conditions as in the first embodiment. By doing so, a gradient composition film 22 having a gradient composition from the solid electrolyte composition to the fuel electrode composition can be formed on the inner peripheral surface of the base tube 10 as shown in FIG.
[0047]
The gradient composition film 22 ranging from the solid electrolyte composition to the fuel electrode composition formed on the inner peripheral surface of the base tube 10 in this manner is obtained by sequentially applying material slurries of a plurality of compositions to the inner peripheral surface of the base tube 10 by the scraper 12. Since the coating films 21a to 21c are formed and fired, the same effects as in the first to third embodiments can be expected. As a result, the gradient composition film 22 is also formed as a film. The thickness is uniform and the adhesion to the base tube 10 is good. In addition, since the solid electrolyte and the fuel electrode are formed in the same film forming process, the manufacturing process can be simplified and the film forming time can be shortened.
[0048]
【Example】
(Example 1)
A base tube made of LSM having an outer diameter of 21 mmφ, an inner diameter of 17 mmφ, and a length of 50 cm serving as an air electrode was horizontally held, and a 14 mmφ slurry supply tube and a screw rod were inserted therein. A wrap-shaped scraper made of hard rubber having an outer diameter of 16.6 mmφ is attached to the tip of the screw rod. Then, a solid electrolyte material slurry having a viscosity of 100,000 mPa · s in which 20 wt% of YSZ powder is mixed with an ethanol diluent and an acrylic binder is supplied to the slurry supply pipe at a rate of 0.3 g / sec, and the screw rod is rotated. While slowly extruding into the substrate tube at a speed of 5 cm / sec.
[0049]
Observation of the solid electrolyte material coating film formed inside showed that the film thickness was 150 μm and was uniformly applied to the inner peripheral surface of the base tube.
[0050]
Subsequently, the substrate tube was placed in a firing furnace and fired. The firing conditions were 1500 ° C. for 10 hours. As a result, the solid electrolyte film formed on the inner peripheral surface of the base tube had a uniform thickness of 70 μm.
[0051]
(Example 2)
A YSZ film serving as a solid electrolyte is formed on the inner peripheral surface of an LSM tube having an outer diameter of 21 mmφ serving as an air electrode, and a base tube having an outer diameter of 21 mmφ, an inner diameter of 17 mmφ, and a length of 50 cm is horizontally held, The same slurry supply pipe and screw rod as in Example 1 were inserted. Then, a fuel electrode material slurry having a viscosity of 10,000 mPa · s obtained by mixing a mixed powder of Ni powder 60 wt%: YSZ powder 40 wt% and a cellulose binder at a ratio of 60 wt%: 40 wt% to a slurry supply pipe at 0.5 g / sec. , And the material was slowly pulled out at a speed of 3 cm / sec while extruding the material slurry into the base tube by rotating the screw rod.
[0052]
When the fuel electrode material layer coating film formed inside was observed, it was found to have a uniform thickness of 170 μm.
[0053]
Subsequently, the substrate tube was placed in a firing furnace and fired. The firing conditions were the same as in Example 1. As a result, the fuel electrode film formed on the inner peripheral surface of the base tube had a uniform thickness of 70 μm.
[0054]
(Example 3)
A solid electrolyte material slurry having a viscosity of 100,000 mPa · s in which 10 to 40 wt% of YSZ powder is mixed with an acrylic binder is applied to the inner peripheral surface of a base tube having the same specifications as in Example 1 under the same conditions as in Example 1. Then, a solid electrolyte material coating 21a of 100 μm was formed and dried.
[0055]
Subsequently, a mixed powder obtained by mixing nickel (Ni) powder and YSZ powder at a ratio of 50 wt%: 50 wt% and a diluent for a cellulose-based binder are applied to the inner peripheral surface of the solid electrolyte material coating film 21 a. Using a slurry of an intermediate composition between the solid electrolyte composition and the fuel electrode composition having a viscosity of 5,000 mPa · s mixed at a ratio of 1: 1 and applying the same conditions as in the case of the solid electrolyte material slurry, A material coating 21b having an intermediate composition with the fuel electrode was formed and dried.
[0056]
Further, a fuel electrode material slurry having the same composition as in Example 2 is applied to the inner peripheral surface of the material coating film 21b having the intermediate composition under the same conditions as in Example 2 to form an 80 μm fuel electrode material coating film 21c. And dried.
[0057]
Thereafter, the substrate tube 10 on which the three material coatings 21a to 21c were formed was fired in a firing furnace. The firing conditions were 1400 ° C. for 5 hours. As a result, a gradient composition film 22 having a composition gradient from the solid electrolyte composition to the fuel electrode composition could be formed on the inner peripheral surface of the base tube, and the overall film thickness was uniform at 60 μm.
[0058]
【The invention's effect】
As described above, according to the fuel cell material coating apparatus of the first aspect of the present invention, the base tube is held by the base tube holding means, and the slurry supply tube in which the rotating screw rod is inserted is inserted into the base tube. The fuel cell material slurry is moved forward by rotating the screw rod. Uniformly While extruding into the base tube as it is extruded, the slurry supply tube is moved in the longitudinal direction of the base tube, and is extruded from the slurry supply tube by a rubber elastic trumpet-shaped scraper attached to the tip of the screw rod, Filled in the gap between the scraper and the base tube The fuel cell material slurry is rubbed to a predetermined thickness on the inner wall of the base tube to form a fuel cell material coating film. Therefore, the flexibility of the scraper allows the fuel cell material slurry to have a uniform thickness on each inner peripheral surface of the base tube. Can be formed, and by adjusting the position where the material slurry is extruded from the slurry supply pipe, the material coating can be formed only at a desired position in the longitudinal direction of the base tube, Further, the material slurry to be supplied to the slurry supply pipe can be a relatively high viscosity that can be extruded with a screw rod, and the material slurry applied to the inner peripheral surface of the base pipe does not move by its own weight. In addition, the thickness of the coating of the fuel cell material can be adjusted accurately.
[0059]
According to the fuel cell material coating method of the invention of claim 2, the screw rod is rotated from the slurry supply pipe into the base pipe. Forward uniformly Extruded, Filled in the gap between the rubber pipe and the scraper with rubber elasticity The scraper is moved along with the slurry supply pipe and the screw rod while the solid electrolyte material slurry is rubbed on the inner wall of the base pipe by a trumpet-shaped scraper, so that the material slurry is uniformly distributed on the inner peripheral surface of the base pipe by the flexibility of the scraper. Can be moved while being rubbed to form a coating film of the solid electrolyte material slurry with a uniform film thickness.
Further, by adjusting the position where the material slurry is extruded from the slurry supply pipe, the material coating can be formed only at a desired position in the longitudinal direction of the base pipe. Further, the material slurry to be supplied to the slurry supply pipe can be a relatively high viscosity that can be extruded with a screw rod, and the material slurry applied to the inner peripheral surface of the base pipe does not move by its own weight. In addition, the thickness of the solid electrolyte material coating can be accurately adjusted.
[0060]
According to the method for forming a fuel cell material according to the third aspect of the present invention, the solid electrolyte material slurry applied to the inside of the base tube by the method for applying the fuel cell material according to the second aspect is dried, and the solid electrolyte material is heated at a predetermined firing temperature. Since the solid electrolyte is formed by firing the film, a solid electrolyte having a uniform film thickness can be easily formed.
[0061]
According to the fuel cell material coating method of the invention of claim 4, the screw rod is rotated from the slurry supply pipe into the base pipe. Forward uniformly Extruded, Filled in the gap between the rubber pipe and the scraper with rubber elasticity Fuel material slurry this The scraper moves along with the slurry supply pipe and the screw rod while rubbing the inner wall of the base tube with the scraper. A coating film of the fuel electrode material slurry can be formed with an appropriate film thickness. Further, by adjusting the position where the material slurry is extruded from the slurry supply pipe, the material coating can be formed only at a desired position in the longitudinal direction of the base pipe. Furthermore, the material slurry to be supplied to the slurry supply pipe can be one having a relatively high viscosity that can be extruded with a screw rod, and the material slurry applied to the inner peripheral surface of the base pipe does not move by its own weight. The thickness of the coating of the fuel electrode material can be adjusted accurately.
[0062]
According to the fuel cell material film forming method of the present invention, the fuel electrode material slurry applied to the inside of the base tube by the fuel cell material applying method of the present invention is dried, and the fuel electrode material slurry is dried at a predetermined firing temperature. Since the fuel film is formed by firing the material film, a fuel electrode having a uniform thickness can be easily formed.
[0063]
According to the method for forming a fuel cell material according to the invention of claim 6, a plurality of types of material slurries that change stepwise from the solid electrolyte composition to the fuel electrode composition are prepared, and a slurry supply pipe inserted into the base pipe is used. While extruding the selected material slurry into the substrate tube by the rotating screw rod, Filling the gap between the rubber elastic scraper and the base tube, By repeating the process of applying the material slurry to the inner wall of the base tube with a scraper to a predetermined film thickness and applying the same to each of the material slurries having a plurality of compositions, a coating having a gradient composition from the solid electrolyte composition to the fuel electrode composition is repeated. The film can be formed to a uniform thickness on the inner peripheral surface of the base tube, and the subsequent firing step can form a material film having a gradient from the solid electrolyte composition to the fuel electrode composition to a uniform thickness. it can.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a coating apparatus used in a method for coating a fuel cell material according to the present invention.
FIG. 2 is a cross-sectional view showing a state in which the solid electrolyte material is applied to the inner peripheral surface of the base tube by the method for applying a fuel cell material according to the first embodiment of the present invention.
FIG. 3 is a cross-sectional view showing a state in which a fuel electrode material is applied to an inner peripheral surface of a base tube by a method for applying a fuel cell material according to a second embodiment of the present invention.
FIG. 4 is a cross-sectional view showing a state in which a solid electrolyte material and a fuel electrode material are applied to an inner peripheral surface of a base tube by a method for applying a fuel cell material according to a third embodiment of the present invention.
FIG. 5 is a cross-sectional view showing a state in which three types of gradient composition material coating films are applied in the fuel cell material film forming method according to the fourth embodiment of the present invention.
FIG. 6 is a cross-sectional view of a fuel cell unit formed by the method for forming a fuel cell material according to the fourth embodiment.
FIG. 7 is a sectional view showing the structure of a general cylindrical solid oxide fuel cell.
[Explanation of symbols]
1 air electrode
2 Solid electrolyte
10 Base tube
11 Slurry supply pipe
12 Scraper
13 Screw rod
14 Slurry supply port
15 Fuel cell material slurry
16, 16a, 16b coating
17 Solid electrolyte
18 Fuel electrode
21a, 21b, 21c coating
22 Gradient composition film

Claims

Substrate tube holding means for holding the substrate tube;
A slurry supply pipe inserted movably in the axial direction into the base tube held by the base tube holding means,
The fuel cell material slurry supplied to the slurry supply pipe and supplied to the slurry supply pipe is uniformly pushed forward by rotation, and while the slurry is being pushed into the base pipe, the slurry is moved in the axial direction together with the slurry supply pipe. A possible sricket stick,
And a horn-shaped scraper having rubber elasticity which is attached to the distal end of the screw rod,
The fuel cell material slurry extruded from the slurry supply pipe is filled in a gap formed between the inner wall of the base pipe and the scraper, and the scraper and the slurry supply pipe are moved in a longitudinal direction to form a predetermined thickness. A fuel cell material application device , characterized by being attached.

Holding the substrate tube,
A slurry supply pipe having a rotating screw rod inserted therein is inserted into the base pipe, and the solid electrolyte material slurry is extruded uniformly into the base pipe by rotating the screw rod so that the slurry is supplied into the base pipe. Moving the tube in the longitudinal direction of the substrate tube,
The solid electrolyte material slurry extruded from the slurry supply pipe by the rubber-elastic flapper-shaped scraper attached to the tip of the screw rod, and filled in the gap formed by the scraper and the base pipe is used as the base pipe. A method for applying a fuel cell material, wherein the inner wall is rubbed to a predetermined thickness.

Drying the solid electrolyte material slurry applied in the base tube by the method for applying a fuel cell material according to claim 2,
A method for forming a fuel cell material, comprising: firing the solid electrolyte material film at a predetermined firing temperature to form a solid electrolyte.

Holding the substrate tube,
A slurry supply pipe having a rotating screw rod inserted therein is inserted into the base pipe, and while the fuel electrode material slurry is uniformly pushed forward by the rotation of the screw rod, the slurry supply pipe is pushed into the base pipe. Moving the tube in the longitudinal direction of the substrate tube,
The fuel electrode material slurry extruded from the slurry supply pipe by a rubber elastic trumpet-shaped scraper attached to the tip of the screw rod, and filled in the gap formed by the scraper and the base pipe is used as the base pipe. A method for applying a fuel cell material, wherein the inner wall is rubbed to a predetermined thickness.

Drying the fuel electrode material slurry applied in the base tube by the method for applying a fuel cell material according to claim 4,
A method for forming a fuel cell material, wherein the fuel electrode material film is fired at a predetermined firing temperature to form a fuel electrode.

Preparing material slurries of a plurality of compositions that change stepwise from the solid electrolyte composition to the fuel electrode composition, selecting one of the material slurries of the plurality of compositions one by one in order from the solid electrolyte composition to the fuel electrode composition,
Holding the substrate tube, inserting a slurry supply tube into which a rotating screw rod is inserted into the substrate tube, and uniformly extruding the selected material slurry forward by the rotation of the screw rod. While extruding into the pipe, the slurry supply pipe is moved in the longitudinal direction of the base pipe, and is extruded from the slurry supply pipe by a rubber-elastic flapper-shaped scraper attached to the tip of the screw rod, and the scraper and the The selected material slurry filled in the gap formed by the base tube is rubbed and applied to the inner wall of the base tube to a predetermined film thickness to sequentially form a coating film of the material slurry having the plurality of types of compositions,
The method is characterized in that a plurality of coating films of the plurality of compositions are simultaneously fired to form a material film having a graded composition ranging from a solid electrolyte composition to a fuel electrode composition on an inner peripheral surface of the base tube. A method for forming a fuel cell material.