JP3898539B2

JP3898539B2 - Fuel cell

Info

Publication number: JP3898539B2
Application number: JP2002079072A
Authority: JP
Inventors: 成門高橋; 高志重久
Original assignee: Kyocera Corp
Current assignee: Kyocera Corp
Priority date: 2002-03-20
Filing date: 2002-03-20
Publication date: 2007-03-28
Anticipated expiration: 2022-03-20
Also published as: JP2003282101A

Description

【０００１】
【発明の属する技術分野】
本発明は、燃料電池に関するもので、特に複数の燃料電池セルの集電特性が良好な燃料電池に関するものである。
【０００２】
【従来技術】
次世代エネルギーとして、近年、複数の燃料電池セルを収納容器内に収納した燃料電池が種々提案されている。
【０００３】
従来の固体電解質型燃料電池は、複数の燃料電池セルを収納容器内に収納し、燃料電池セル同士を集電部材により電気的に直列又は並列に接続して構成されており、発電は燃料電池セルに酸素含有ガス及び燃料ガスを供給して６００〜１０００℃程度の高温で行われていた。
【０００４】
そして、燃料電池セル間の電気的な接続を行う集電部材は、従来、繊維状の金属が集合した金属フェルト状のものが用いられていた。このようなフェルト状の集電部材を用いた燃料電池は、複数の燃料電池セルを配列集合させ、例えば、一方の燃料電池セルのインターコネクタと、他方の燃料電池セルの外側電極との間に、フェルト状の集電部材を詰め込み燃料電池セルを直列に接続してセルスタックを形成し、このセルスタックを収納容器内に収納して構成されていた。
【０００５】
【発明が解決しようとする課題】
しかしながら、上記した燃料電池では、フェルト状の集電部材が繊維状の金属から構成されているため、一方の燃料電池セルのインターコネクタと、他方の燃料電池セルの外側電極とは点接触となり、集電特性が未だ低いという問題があった。
【０００６】
また、燃料電池セル間に集電部材を詰め込んだとしても、振動や集電部材の弾性低下等の原因で燃料電池セルとの接触が十分に行われなくなり、発電当初は集電特性はある程度良好であったとしても経時的に低下する可能性があった。
【０００７】
さらに、燃料電池セル間に空気等の酸素含有ガスが導入されて発電する場合には、繊維状金属の表面から酸化し、集電特性が低下し、また金属フェルトの弾性力が低下し、経時的に特定が低下するという問題もあった。
【０００８】
また、一方の燃料電池セルのインターコネクタと他方の燃料電池セルの外側電極との間に集電部材を詰め込む際に、集電部材がフェルト状であることに起因して、一方の燃料電池セルと他方の燃料電池セルの外側電極同士が導通してしまうという危険性もあった。
【０００９】
本発明は、燃料電池セル間の集電特性を向上できる燃料電池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】
本発明の燃料電池は、内部にガス通過孔を有し断面が扁平状で柱状の複数の燃料電池セルを収納容器内に配列して収納し、前記複数の燃料電池セル間に板状集電部材を配置し、対向する前記燃料電池セル同士を電気的に接続してなるとともに、前記板状集電部材の一部に複数の切れ目であるスリットを平行に形成し、該スリット間の集電片を前記板状集電部材の両側に交互に突出させ、前記対向する燃料電池セルの平坦な外面にそれぞれ面接触せしめてなることを特徴とする。
【００１１】
板状集電部材は、基部の一端部に複数の集電片が形成された櫛歯形状としたり、複数の集電片群を燃料電池セルの長さ方向に所定間隔を置いて形成して構成することができる。
板状集電部材が櫛歯形状である場合には、対向する燃料電池セル間に基部から挿入されることが望ましい。
【００１２】
このような燃料電池では、板状集電部材のバネ性を有する集電片により燃料電池セル間を機械的に接続しているため、燃料電池セルとは面接触となり、従来のようなフェルト状の集電部材よりも燃料電池セルに当接する面積が大きくなり、集電特性を向上できる。さらに、板状集電部材の集電片が両側に交互に突出しており、集電片間に形成された隙間へガス供給でき、発電特性を向上できる。
【００１３】
また、集電片は板状であるため弾性力も大きく、振動等が生じたとしても燃料電池セルとの十分な接触を長期間確保できる。さらに、集電片は板状であるため、収納容器内が高温となった場合でも、従来のフェルト状の集電部材よりも焼結しにくく、また、燃料電池セルとの十分な接触を長期間確保できる。
【００１４】
さらに、集電部材が板状であるため、例えば、一方の燃料電池セルのインターコネクタと他方の燃料電池セルの外側電極との間に集電部材を詰め込む際にも、一方の燃料電池セルと他方の燃料電池セルの外側電極同士の導通を確実に防止できる。
【００１５】
また、本発明の燃料電池では、燃料電池セルは扁平状であり、対向する燃料電池セル外面は平坦であるため、板状集電部材の集電片が燃料電池セル外面に確実に当接するため、集電特性を向上できる。
【００１６】
本発明の燃料電池では、燃料電池セルは、軸長方向にガス通過孔が形成された内側電極の表面に、固体電解質、外側電極を順次形成し、前記固体電解質及び前記外側電極が形成されていない内側電極の表面にインターコネクタを形成してなり、一方の燃料電池セルのインターコネクタと他方の燃料電池セルの外側電極に、板状集電部材の集電片が当接していることを特徴とする。このように燃料電池セルを電気的に直列に接続する場合に好適に用いられる。
【００１７】
また、本発明の燃料電池では、燃料電池セルは、酸素含有ガスに曝される外側電極を有しており、板状集電部材が、導電性を有する金属又は合金の表面を耐酸化性物質で被覆して構成されていることが望ましい。板状集電部材が耐酸化性を有するため、板状集電部材が酸素含有ガスに曝されたとしても良好な電気伝導性を有することができる。
【００１８】
【発明の実施の形態】
図１は、本発明の燃料電池の一形態を示すもので、符号３１は断熱構造を有する収納容器を示している。この収納容器３１の内部には、複数の燃料電池セル３３と、これらの燃料電池セル３３の上方に形成された燃焼室３７と、この燃焼室３７を挿通する酸素含有ガス供給管３９と、燃焼室３７の上方に設けられた熱交換部４１とが設けられている。
【００１９】
収納容器３１は、耐熱性金属からなる枠体３１ａと、この枠体３１ａの内面に設けられた断熱材３１ｂとから構成されている。
【００２０】
収納容器３１内の燃料電池セル３３は、図２に示すように、３列に整列しており、隣設した２列の最外部の燃料電池セル３３の電極同士が導電部材４２で接続され、これにより３列に整列した複数の燃料電池セル３３が電気的に直列に接続している。尚、図１では燃料電池セルを４列に整列した状態を記載した。
【００２１】
具体的に説明すると、燃料電池セル３３は断面が扁平状で、全体的に見て楕円柱状であり、その内部には複数の燃料ガス通路３４が形成されている。この燃料電池セル３３は、断面が扁平状で、全体的に見て楕円柱状の多孔質な金属を主成分とする燃料側電極（内側電極）３３ａの外面に、緻密質な固体電解質３３ｂ、多孔質な導電性セラミックスからなる酸素側電極（外側電極）３３ｃを順次積層し、酸素側電極３３ｃと反対側の燃料側電極３３ａの外面にインターコネクタ３３ｄを形成して構成されており、燃料側電極３３ａが支持体となっている。
【００２２】
即ち、燃料電池セル３３は、断面形状が、幅方向両端に設けられた弧状部と、これらの弧状部を連結する一対の平坦部とから構成されており、一対の平坦部は平坦であり、ほぼ平行に形成されている。これらの一対の平坦部は、燃料側電極３３ａの平坦部にインターコネクタ３３ｄ、又は固体電解質３３ｂ、酸素側電極３３ｃを形成して構成されている。
【００２３】
一方の燃料電池セル３３と他方の燃料電池セル３３との間には板状集電部材４３が介在され、一方の燃料電池セル３３の燃料側電極３３ａは、該燃料側電極３３ａに設けられたインターコネクタ３３ｄ、集電部材４３を介して他方の燃料電池セル３３の酸素側電極３３ｃに電気的に接続されている。尚、図３では、集電部材４３を簡略化して記載した。
【００２４】
板状集電部材４３は、図３に示すように、矩形状板の一端部に複数のスリットを略平行に形成し、該スリット間の集電片４３ａを板状集電部材４３の両側に交互に突出させ、基部４３ｂの一端部に複数の集電片４３ａが形成された櫛歯形状とされ、複数の集電片４３ａが対向する燃料電池セル３３の外面にそれぞれ当接している。
【００２５】
即ち、集電片４３ａは、対向する燃料電池セル３３の平坦部であるインターコネクタ３３ｄと、酸素側電極３３ｃ間に配置され、燃料電池セル３３同士が直列に接続されている。平坦部に集電片４３ａが当接しているため確実に当接し、電気的接続を確実に行うことができる。また、複数の集電片４３ａはＡｇペーストを介在して燃料電池セル３３に接合している。このＡｇペーストは発電時に焼き付けられ、集電片４３ａと燃料電池セル３３のインターコネクタ３３ｄと酸素側電極３３ｃに接合し、これにより、集電片４３ａと燃料電池セル３３との電気的接続を十分にとることができる。集電片４３ａの幅は、集電特性を向上し、集電片４３ａ間に十分に酸素含有ガスを供給するという点から、２ｍｍ以下が望ましい。
【００２６】
これらの板状集電部材４３は、対向する燃料電池セル３３間に複数配置されており、対向する燃料電池セル３３間に基部４３ｂから挿入され、基部４３ｂが下に位置している。これらの板状集電部材４３は、導電性を有するＣｒ、Ｆｅを主成分とするフェライト系ステンレスの表面をＡｇからなる耐酸化性物質で被覆して構成されている。尚、板状集電部材４３は導電性を有する金属又は合金を主成分とするものの表面を耐酸化性物質で被覆したものであれば、上記したものに限定されるものではない。
【００２７】
対向する燃料電池セル３３間には、図４に示す板状集電部材４４を介在せしめても良い。図４に示す板状集電部材４４は、複数のスリットを略平行に形成し、その間の集電片４４ａを交互に板状集電部材４４の両側に突出させて形成された集電片４４ａ群を、長さ方向に所定間隔を置いて形成して構成し、基部４４ｂと集電片４４ａを交互に形成しても良い。図４に示すような板状集電部材４４では、図３の板状集電部材４３よりも燃料電池セル間への配置を簡単に行うことができる。
【００２８】
また、図４（ｃ）に示すように、複数の集電片４６ａ群を長さ方向に所定間隔を置いて形成し、一つの集電片４６ａ群において集電片４６ａを一つおきに一方の燃料電池セル３３の酸素側電極３３ｃ側に突出させて当接せしめ、その他の平坦な部分を他方の燃料電池セル３３のインターコネクタ３３ｄに当接せしめるようにしても良い。この場合、インターコネクタ３３ｄとの接合を十分に行うことができる。
【００２９】
燃料電池セル３３の下方には、図１に示したように、燃料ガスを燃料電池セル３３に供給するための燃料ガスタンク４５が設けられ、この燃料ガスタンク４５には、外部から燃料ガスを燃料ガスタンク４５に供給するための燃料ガス供給管５１が接続されている。
【００３０】
燃料ガスタンク４５には、燃料電池セル３３の下端部に取り付けられた取付治具５３が螺着しており、これにより、燃料電池セル３３が燃料ガスタンク４５にそれぞれ立設している。即ち、取付治具５３は、燃料電池セル３３の端部に取り付けられたセル端部側取付治具５３ａと、両端部がセル端部側取付治具５３ａ及び燃料ガスタンク４５にそれぞれ螺着する連結部材５３ｂとから構成されており、連結部材５３ｂの両端部には向きが逆のねじ部が形成され、連結部材５３ｂを一方側に回転させると、両端部がセル端部側取付治具５３ａ及び燃料ガスタンク４５にそれぞれ螺着するように形成されている。
【００３１】
セル端部側取付治具５３ａ、連結部材５３ｂには、燃料ガスタンク４５と燃料電池セル３３の燃料ガス通路３４に連通するように貫通孔が形成されている。
【００３２】
また、図１に示したように、燃焼室３７を挿通する酸素含有ガス供給管３９は、その先端部が燃料電池セル３３間に位置している。発電で用いられなかった余剰の酸素含有ガスは、燃料電池セル３３間を通って燃料電池セル３３の上方に流れ、発電で用いられなかった余剰の燃料ガスは、燃料電池セル３３の燃料ガス通路３４を通って燃料電池セル３３の上方から吹き出し、燃料電池セル３３の上端近傍において、燃料ガスと酸素含有ガスが反応して燃焼するように構成されている。
【００３３】
熱交換部４１は、熱交換器４１ａと、燃焼室３７を介してセルスタック３５に対向して設けられた酸素含有ガス収容室４１ｂとから構成されている。
【００３４】
熱交換器４１ａは、図５に示すように、平板６１と波板６３を交互に積層したプレートフィン型構造とされており、酸素含有ガス収容室４１ｂと連通する通路を形成する波板６３ａは、図５（ｂ）に示すように形成され、また、燃焼ガスの排出用の通路を形成する波板６３ｂは、図５（ｃ）に示すように形成されている。
【００３５】
燃焼ガスは、図１に一点鎖線で示したように熱交換器４１ａの下部側面から導入され、熱交換器４１ａの上方へ排出され、一方、酸素含有ガスは、図１に破線で示したように熱交換器４１ａの上部側面から導入され、熱交換器４１ａの下方へ導かれ、酸素含有ガス収容室４１ｂ内に導入される。
【００３６】
酸素含有ガス収容室４１ｂは、図６に示すように、熱交換器４１ａの酸素含有ガスが導入される側の端面、即ち燃料電池セル３３側端面に設けられており、波板６３ａの各通路を通過した酸素含有ガスが一旦収容されるようになっている。
【００３７】
酸素含有ガス収容室４１ｂには、複数の酸素含有ガス供給管３９の一端が開口し、連通している。
【００３８】
また、図１に示したように、酸素含有ガス収容室４１ｂの側面と断熱材３１ｂとの間、即ち酸素含有ガス収容室４１ｂの周囲は、燃焼室３７中の燃焼ガスを熱交換器４１ａに導入する燃焼ガス導入口７１とされている。この燃焼ガス導入口７１を介して燃焼ガスが熱交換器４１ａの波板６３ｂの通路へ導出される。
【００３９】
以上のように構成された燃料電池では、外部からの酸素含有ガス（例えば空気）を酸素含有ガス管７３を介して熱交換器４１ａに導入し、酸素含有ガス収容室４１ｂに導入し、酸素含有ガス供給管３９を介して燃料電池セル３３間に噴出させるとともに、燃料ガス（例えば水素）を燃料ガス供給管５１を介して燃料電池セル３３の燃料ガス通路３４内に供給し発電させる。
【００４０】
発電に用いられなかった余剰の燃料ガスは燃料ガス通路３４の上端から燃焼室３７内に噴出し、発電に用いれらなかった余剰の酸素含有ガスは燃焼室３７内に流れ、余剰の燃料ガスと余剰の酸素含有ガスを反応させて燃焼させ、燃焼ガスを発生させ、この燃焼ガスが燃焼ガス導入口７１を介して熱交換器４１ａに導出され、熱交換器４１ａの上端から排出される。
【００４１】
そして、本発明の燃料電池では、板状集電部材４３、４４、４６のバネ性を有する集電片４３ａ、４４ａ、４６ａにより燃料電池セル３３間を機械的に接続しているため、燃料電池セル３３とは面接触となり、従来のようなフェルト状の集電部材よりも燃料電池セル３３に当接する面積が大きくなり、集電特性を向上できる。また、集電片４３ａ、４４ａ、４６ａは板状であるため弾性力も大きく、振動等が生じたとしても燃料電池セル３３との十分な接触を長期間確保できる。
【００４２】
また、集電片４３ａ、４４ａ、４６ａ間には隙間が形成されているので、酸素含有ガスが隙間、酸素側電極３３ｃを介して、固体電解質３３ｂへ供給され、発電が良好となる。
【００４３】
さらに、集電片４３ａ、４４ａ、４６ａは板状であるため、収納容器３１内が高温となった場合でも、従来のフェルト状の集電部材よりも焼結しにくく、また、燃料電池セル３３との十分な接触を長期間確保できる。さらに、集電部材４３、４４、４６が板状であるため、一方の燃料電池セル３３のインターコネクタ３３ｄと他方の燃料電池セル３３の酸素側電極３３ｃとの間に板状集電部材４３、４４、４６を介装する際にも、一方の燃料電池セル３３と他方の燃料電池セル３３の酸素側電極３３ｃ同士の導通を確実に防止できる。
【００４４】
また、発電に寄与しなかった余剰の燃料ガスと酸素含有ガスが燃焼室３７内に導入され、この燃焼室３７中で反応して燃焼し、この燃焼ガス及び外部の酸素含有ガスを熱交換器４１ａに導入し、この熱交換器４１ａで燃焼ガスと酸素含有ガスとの間で熱交換させ、起動時に酸素含有ガスを予熱することができ、また、酸素含有ガス供給管３９が燃焼室３７を挿通することにより、燃焼ガスにより酸素含有ガス供給管３９内の酸素含有ガスをさらに加熱することができるため、加熱した酸素含有ガスにより燃料電池セル３３を間接的に加熱して実質的に発電するまでの起動時間を短縮できる。
【００４５】
さらに、燃料電池セル３３の上部に燃焼室３７、酸素含有ガス収容室４１ｂ、熱交換器４１ａが隣接して形成されているため、燃焼室３７で燃焼した高温の燃焼ガスを、配管等を用いることなく熱交換器４１ａに直接導入でき、簡単な構造で酸素含有ガスの予熱効率を大きくできる。
【００４６】
また、収納容器３１内で、燃焼ガスと酸素含有ガスとを熱交換できるため、酸素含有ガスの予熱を行うためのバーナーを収納容器３１内に別途設ける必要がなく、小型にでき、しかも燃焼ガスを有効利用できる。
【００４７】
さらに、熱交換器４１ａに酸素含有ガス収容室４１ｂを設けたので、熱交換器４１ａと酸素含有ガス供給管３９との接続を酸素含有ガス収容室４１ｂを介して行うことができ、熱交換器４１ａからの酸素含有ガスを発電室４９内に確実に供給できる。
【００４８】
尚、本発明は上記形態に限定されるものではなく、発明の要旨を変更しない範囲で種々の変更が可能である。
【００４９】
また、熱交換器４１ａとしてプレートフィン型を用いたが、本発明ではこれに限定されるものではなく、それ以外の熱交換器を用いても良いことは勿論である。
【００５０】
さらに、上記例では、燃料電池セル３３を直列に接続した例について説明したが、並列接続しても良いことは勿論である。また、燃料側電極３３ａを内側電極としたが、酸素側電極を内側電極としても良い。
【００５１】
【実施例】
先ず、平均粒径０．５μｍのＮｉＯ粉末と、平均粒径０．５μｍのＹを８モル％含有したＺｒＯ₂（ＹＳＺ）粉末と、ポアー剤、ＰＶＡからなる有機バインダーと、水からなる溶媒とを混合した燃料側電極材料を押出成形して、図２に示したような扁平状の燃料側電極成形体を作製し、これを乾燥した。
【００５２】
次に、上記ＹＳＺ粉末と、アクリル樹脂からなる有機バインダーと、トルエンからなる溶媒とを混合した、固体電解質材料を用いてシート状成形体を作製し、このシート状成形体を、燃料側電極成形体上に、その両端間が、燃料側電極の平坦部部分で所定間隔をおいて離間するように巻き付け、乾燥した。
【００５３】
この後、平均粒径２μｍのＬａＣｒＯ₃系材料と、アクリル樹脂からなる有機バインダーと、トルエンからなる溶媒とを混合した、インターコネクタ材料を用いてシート状成形体を作製し、このシート状成形体を、固体電解質のシート状成形体間であって、露出した燃料側電極成形体の外面に積層し、燃料側電極成形体に固体電解質のシート状成形体、インターコネクタのシート状成形体が積層された積層成形体を作製した。
【００５４】
次に、この積層成形体を脱バインダー処理し、大気中にて１５００℃で同時焼成した。この積層体を、平均粒径２μｍのＬａ_0.6Ｓｒ_0.4Ｃｏ_0.2Ｆｅ_0.8Ｏ₃粉末と、ノルマルパラフィンからなる溶媒を含有するペースト中に浸漬し、固体電解質の表面に酸素側電極成形体をディッピングにより作製し、１１５０℃で焼き付け、図２に示したような燃料電池セルを複数作製した。
【００５５】
そして、一対の燃料電池セルを配列させ、一方の燃料電池セルのインターコネクタと他方の燃料電池セルの燃料側電極との間に、Ｆｅ、Ｃｒを主成分とするフェライト系ステンレス表面をＡｇで被覆した板材に多数の集電片を形成した図３の板状集電部材を、Ａｇペーストを介在させて配置した。
【００５６】
そして、燃料電池セルの外側に空気を供給した状態で、集電部材が介装された燃料電池セルを８５０℃に加熱し、一方の燃料電池セルのインターコネクタと他方の燃料電池セルの酸素側電極との間の電気抵抗を測定した。
【００５７】
また、一対の燃料電池セル間に、Ｆｅ、Ｃｒを主成分とするフェライト系ステンレスからなるフェルト状の集電部材をＡｇペーストを介して配置した比較例についても同様に電気抵抗を測定した。
【００５８】
この結果、本発明の板状集電部材では、３０ｍΩｃｍ²と非常に良い電気伝導性が得られたのに対して、フェルト状の集電部材を用いた比較例では、３００ｍΩｃｍ²と電気伝導性が低かった。
【００５９】
【発明の効果】
本発明の燃料電池では、板状集電部材のバネ性を有する集電片により燃料電池セル間を機械的に接続しているため、燃料電池セルとは面接触となり、従来のようなフェルト状の集電部材よりも燃料電池セルに当接する面積が大きくなり、集電特性を向上できる。また、集電片は板状であるため弾性力も大きく、振動等が生じたとしても燃料電池セルとの十分な接触を長期間確保できる。
【００６０】
さらに、集電片は板状であるため、収納容器内が高温となった場合でも、従来のフェルト状の集電部材よりも焼結しにくく、また、燃料電池セルとの十分な接触を長期間確保できる。さらにまた、集電部材が板状であるため、例えば、一方の燃料電池セルのインターコネクタと他方の燃料電池セルの外側電極との間に集電部材を詰め込む際にも、一方の燃料電池セルと他方の燃料電池セルの外側電極同士の導通を確実に防止できる。
【図面の簡単な説明】
【図１】本発明の燃料電池を示す説明図である。
【図２】図１のセルスタックを示す横断面図である。
【図３】基部の一端部に複数の集電片が形成された櫛歯形状の板状集電部材を用いて、燃料電池セルを接続した状態を示すもので、（ａ）は側面図、（ｂ）は板状集電部材を示す斜視図である。
【図４】複数の集電片群を長さ方向に所定間隔を置いて形成して構成した板状集電部材を用いて、燃料電池セルを接続した状態を示すもので、（ａ）は側面図、（ｂ）は板状集電部材を示す斜視図、（ｃ）は集電片を一方側のみ突出させた板状集電部材を示す斜視図である。
【図５】図１の熱交換器の概念を説明するための図であり、（ａ）は熱交換器の斜視図、（ｂ）は酸素含有ガスの通路を形成するための波板を示す斜視図、（ｃ）は燃焼ガスの通路を形成するための波板を示す斜視図である。
【図６】本発明の熱交換部を説明するための斜視図である。
【符号の説明】
３１・・・収納容器
３３・・・燃料電池セル
４３、４４、４６・・・板状集電部材
４３ａ、４４ａ、４６ａ・・・集電片
４３ｂ、４４ｂ・・・基部
３３ａ・・・燃料側電極（内側電極）
３３ｂ・・・固体電解質
３３ｃ・・・酸素側電極（外側電極）
３３ｄ・・・インターコネクタ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel cell, and more particularly to a fuel cell having a good current collection characteristic of a plurality of fuel cells.
[0002]
[Prior art]
In recent years, various fuel cells in which a plurality of fuel battery cells are stored in a storage container have been proposed as next-generation energy.
[0003]
A conventional solid oxide fuel cell is configured by storing a plurality of fuel cells in a storage container and electrically connecting the fuel cells to each other in series or in parallel by a current collecting member. It was performed at a high temperature of about 600 to 1000 ° C. by supplying an oxygen-containing gas and a fuel gas to the cell.
[0004]
Conventionally, a metal felt-like member in which fibrous metals are gathered has been used as a current collecting member for electrical connection between fuel cells. A fuel cell using such a felt-shaped current collecting member has a plurality of fuel cells arranged and assembled, for example, between an interconnector of one fuel cell and an outer electrode of the other fuel cell. Then, a felt-shaped current collecting member is packed and fuel cell cells are connected in series to form a cell stack, and this cell stack is stored in a storage container.
[0005]
[Problems to be solved by the invention]
However, in the above fuel cell, since the felt-shaped current collecting member is made of a fibrous metal, the interconnector of one fuel cell and the outer electrode of the other fuel cell are in point contact, There was a problem that current collection characteristics were still low.
[0006]
In addition, even if the current collecting member is packed between the fuel cells, the contact with the fuel cell is not sufficiently performed due to vibrations, the elasticity of the current collecting member, etc. Even if it was, it might fall with time.
[0007]
In addition, when an oxygen-containing gas such as air is introduced between the fuel cells to generate electricity, it is oxidized from the surface of the fibrous metal, current collection characteristics are reduced, and the elastic force of the metal felt is reduced. There was also a problem that the identification was reduced.
[0008]
Further, when the current collecting member is packed between the interconnector of one fuel battery cell and the outer electrode of the other fuel battery cell, the one fuel battery cell is caused by the fact that the current collecting member has a felt shape. There was also a risk that the outer electrodes of the other fuel cell would become conductive.
[0009]
An object of this invention is to provide the fuel cell which can improve the current collection characteristic between fuel battery cells.
[0010]
[Means for Solving the Problems]
A fuel cell according to the present invention includes a plurality of columnar fuel cells each having a gas passage hole therein and a flat cross-section , and arranged in a storage container, and a plate-like current collector between the plurality of fuel cells. member arranged, together with the fuel cells facing each other formed by electrically connecting, the slits are a plurality of cuts in a part of the plate-like current collecting member is formed into a flat line, collecting between the slit The electric strips are alternately projected on both sides of the plate-like current collecting member, and are in surface contact with the flat outer surfaces of the opposed fuel cells, respectively.
[0011]
The plate-like current collecting member is formed in a comb-teeth shape in which a plurality of current collecting pieces are formed at one end of the base, or a plurality of current collecting piece groups are formed at predetermined intervals in the length direction of the fuel cell. Can be configured.
When the plate-like current collecting member has a comb-teeth shape, it is desirable that the plate-like current collecting member is inserted from the base between the opposed fuel cells.
[0012]
In such a fuel cell, since the fuel cell is mechanically connected by the current collecting piece having the spring property of the plate-shaped current collecting member, it is in surface contact with the fuel cell and has a felt-like shape as in the prior art. The area in contact with the fuel cell becomes larger than that of the current collecting member, and the current collecting characteristics can be improved. Furthermore, the current collecting pieces of the plate-like current collecting member protrude alternately on both sides, so that gas can be supplied to the gap formed between the current collecting pieces, and the power generation characteristics can be improved.
[0013]
Further, since the current collecting piece is plate-like, the elastic force is large, and even if vibration or the like occurs, sufficient contact with the fuel cell can be ensured for a long time. Furthermore, since the current collecting piece is plate-shaped, it is harder to sinter than the conventional felt-shaped current collecting member even when the temperature of the storage container becomes high, and sufficient contact with the fuel cell is prolonged. A period can be secured.
[0014]
Furthermore, since the current collecting member is plate-shaped, for example, when the current collecting member is packed between the interconnector of one fuel battery cell and the outer electrode of the other fuel battery cell, The conduction between the outer electrodes of the other fuel cell can be reliably prevented.
[0015]
Further, in the fuel cell of the present invention, the fuel cell is flat, since the fuel cell outer surface facing are flat, because the current collecting plates of the plate-like current collecting member to reliably contact with the fuel cell outer surface The current collecting characteristics can be improved.
[0016]
In the fuel cell of the present invention, the fuel cell has a solid electrolyte and an outer electrode sequentially formed on the surface of the inner electrode in which a gas passage hole is formed in the axial direction, and the solid electrolyte and the outer electrode are formed. An interconnector is formed on the surface of the inner electrode that is not present, and the current collector piece of the plate-like current collector is in contact with the interconnector of one fuel cell and the outer electrode of the other fuel cell. And Thus, it is suitably used when the fuel cells are electrically connected in series.
[0017]
In the fuel cell of the present invention, the fuel cell has an outer electrode that is exposed to the oxygen-containing gas, and the plate-like current collecting member has an oxidation-resistant substance on the surface of the conductive metal or alloy. It is desirable to be covered with. Since the plate-like current collecting member has oxidation resistance, even if the plate-like current collecting member is exposed to the oxygen-containing gas, it can have good electrical conductivity.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an embodiment of a fuel cell according to the present invention. Reference numeral 31 denotes a storage container having a heat insulating structure. Inside the storage container 31, a plurality of fuel cells 33, a combustion chamber 37 formed above these fuel cells 33, an oxygen-containing gas supply pipe 39 that passes through the combustion chamber 37, and a combustion A heat exchanging part 41 provided above the chamber 37 is provided.
[0019]
The storage container 31 includes a frame body 31a made of a heat-resistant metal and a heat insulating material 31b provided on the inner surface of the frame body 31a.
[0020]
As shown in FIG. 2, the fuel cells 33 in the storage container 31 are arranged in three rows, and the electrodes of the two outermost fuel cells 33 arranged adjacent to each other are connected by a conductive member 42. Thus, the plurality of fuel cells 33 arranged in three rows are electrically connected in series. FIG. 1 shows a state in which the fuel cells are arranged in four rows.
[0021]
More specifically, the fuel battery cell 33 has a flat cross section and an overall elliptical cylinder shape, and a plurality of fuel gas passages 34 are formed therein. This fuel battery cell 33 has a flat cross section and an outer surface of a fuel side electrode (inner electrode) 33a mainly composed of a porous metal having an elliptic cylinder shape as a whole. The oxygen side electrode (outer electrode) 33c made of high quality conductive ceramics is sequentially laminated, and the interconnector 33d is formed on the outer surface of the fuel side electrode 33a opposite to the oxygen side electrode 33c. 33a is a support.
[0022]
That is, the fuel cell 33 has a cross-sectional shape composed of arc-shaped portions provided at both ends in the width direction, and a pair of flat portions that connect these arc-shaped portions, and the pair of flat portions are flat, They are formed almost in parallel. The pair of flat portions is configured by forming an interconnector 33d, a solid electrolyte 33b, and an oxygen side electrode 33c on the flat portion of the fuel side electrode 33a.
[0023]
A plate-like current collecting member 43 is interposed between one fuel battery cell 33 and the other fuel battery cell 33, and a fuel side electrode 33a of one fuel battery cell 33 is provided on the fuel side electrode 33a. It is electrically connected to the oxygen side electrode 33 c of the other fuel cell 33 through the interconnector 33 d and the current collecting member 43. In FIG. 3, the current collecting member 43 is simplified.
[0024]
As shown in FIG. 3, the plate-like current collecting member 43 is formed with a plurality of slits substantially parallel to one end of a rectangular plate, and current collecting pieces 43 a between the slits are formed on both sides of the plate-like current collecting member 43. A plurality of current collecting pieces 43a are formed at one end of the base portion 43b so as to protrude alternately, and the current collecting pieces 43a are in contact with the outer surfaces of the opposed fuel cells 33, respectively.
[0025]
That is, the current collecting piece 43a is disposed between the interconnector 33d, which is a flat portion of the opposed fuel battery cell 33, and the oxygen side electrode 33c, and the fuel battery cells 33 are connected in series. Since the current collecting piece 43a is in contact with the flat portion, it can be surely contacted and the electrical connection can be reliably performed. The plurality of current collecting pieces 43a are joined to the fuel cell 33 with an Ag paste interposed therebetween. This Ag paste is baked at the time of power generation, and joined to the current collecting piece 43a, the interconnector 33d of the fuel cell 33, and the oxygen side electrode 33c, thereby sufficiently connecting the current collecting piece 43a to the fuel cell 33. Can be taken. The width of the current collecting piece 43a is desirably 2 mm or less from the viewpoint of improving the current collecting characteristics and sufficiently supplying the oxygen-containing gas between the current collecting pieces 43a.
[0026]
A plurality of these plate-like current collecting members 43 are arranged between the opposed fuel cells 33, inserted between the opposed fuel cells 33 from the base 43b, and the base 43b is located below. These plate-like current collecting members 43 are configured by covering the surface of a ferritic stainless steel mainly composed of conductive Cr and Fe with an oxidation-resistant substance made of Ag. The plate-like current collecting member 43 is not limited to the above as long as it has a conductive metal or alloy as a main component and the surface is covered with an oxidation-resistant substance.
[0027]
A plate-like current collecting member 44 shown in FIG. 4 may be interposed between the opposed fuel cells 33. The plate-like current collecting member 44 shown in FIG. 4 is formed by forming a plurality of slits substantially in parallel, and the current collecting pieces 44a therebetween alternately projecting on both sides of the plate-like current collecting member 44. The group may be formed with a predetermined interval in the length direction, and the base portions 44b and the current collecting pieces 44a may be alternately formed. In the plate-like current collecting member 44 as shown in FIG. 4, the arrangement between the fuel cells can be performed more easily than the plate-like current collecting member 43 in FIG.
[0028]
Further, as shown in FIG. 4 (c), a plurality of current collecting pieces 46a are formed at predetermined intervals in the length direction, and one current collecting piece 46a is provided in every other current collecting piece 46a. The fuel cell 33 may be protruded and brought into contact with the oxygen side electrode 33c, and the other flat portion may be brought into contact with the interconnector 33d of the other fuel cell 33. In this case, it is possible to sufficiently join the interconnector 33d.
[0029]
As shown in FIG. 1, a fuel gas tank 45 for supplying fuel gas to the fuel battery cell 33 is provided below the fuel battery cell 33, and the fuel gas tank 45 receives fuel gas from the outside. A fuel gas supply pipe 51 for supplying to 45 is connected.
[0030]
An attachment jig 53 attached to the lower end portion of the fuel battery cell 33 is screwed into the fuel gas tank 45, whereby the fuel battery cell 33 is erected on the fuel gas tank 45, respectively. That is, the attachment jig 53 is connected to the cell end side attachment jig 53a attached to the end of the fuel cell 33 and the both ends screwed to the cell end side attachment jig 53a and the fuel gas tank 45, respectively. The screw 53 is formed in opposite ends at both ends of the connecting member 53b. When the connecting member 53b is rotated to one side, both ends are attached to the cell end side mounting jig 53a and The fuel gas tank 45 is formed so as to be screwed thereto.
[0031]
A through hole is formed in the cell end side attachment jig 53 a and the connecting member 53 b so as to communicate with the fuel gas tank 45 and the fuel gas passage 34 of the fuel cell 33.
[0032]
Further, as shown in FIG. 1, the oxygen-containing gas supply pipe 39 that passes through the combustion chamber 37 has a tip portion located between the fuel cells 33. Excess oxygen-containing gas that has not been used in power generation flows between the fuel cells 33 and flows above the fuel cell 33, and surplus fuel gas that has not been used in power generation passes through the fuel gas passage of the fuel cell 33. The fuel gas is blown out from above the fuel battery cell 33 through 34, and the fuel gas and the oxygen-containing gas are configured to react and burn in the vicinity of the upper end of the fuel battery cell 33.
[0033]
The heat exchange unit 41 includes a heat exchanger 41 a and an oxygen-containing gas storage chamber 41 b provided to face the cell stack 35 via the combustion chamber 37.
[0034]
As shown in FIG. 5, the heat exchanger 41 a has a plate fin type structure in which flat plates 61 and corrugated plates 63 are alternately stacked. The corrugated plate 63 a that forms a passage communicating with the oxygen-containing gas storage chamber 41 b The corrugated plate 63b that is formed as shown in FIG. 5 (b) and that forms a passage for discharging combustion gas is formed as shown in FIG. 5 (c).
[0035]
The combustion gas is introduced from the lower side surface of the heat exchanger 41a as shown by a one-dot chain line in FIG. 1, and is discharged to the upper side of the heat exchanger 41a, while the oxygen-containing gas is shown by a broken line in FIG. Is introduced from the upper side surface of the heat exchanger 41a, led to the lower side of the heat exchanger 41a, and introduced into the oxygen-containing gas storage chamber 41b.
[0036]
As shown in FIG. 6, the oxygen-containing gas storage chamber 41b is provided on the end surface of the heat exchanger 41a on the side where the oxygen-containing gas is introduced, that is, the end surface on the fuel cell 33 side, and each passage of the corrugated plate 63a. The oxygen-containing gas that has passed through is temporarily stored.
[0037]
One ends of a plurality of oxygen-containing gas supply pipes 39 are opened and communicated with the oxygen-containing gas storage chamber 41b.
[0038]
Further, as shown in FIG. 1, the combustion gas in the combustion chamber 37 is transferred to the heat exchanger 41a between the side surface of the oxygen-containing gas storage chamber 41b and the heat insulating material 31b, that is, around the oxygen-containing gas storage chamber 41b. The combustion gas inlet 71 is introduced. The combustion gas is led out to the passage of the corrugated plate 63b of the heat exchanger 41a through the combustion gas introduction port 71.
[0039]
In the fuel cell configured as described above, an oxygen-containing gas (for example, air) from the outside is introduced into the heat exchanger 41a through the oxygen-containing gas pipe 73, and is introduced into the oxygen-containing gas storage chamber 41b. The fuel gas (for example, hydrogen) is ejected between the fuel cells 33 through the gas supply pipe 39 and the fuel gas (for example, hydrogen) is supplied into the fuel gas passage 34 of the fuel cell 33 through the fuel gas supply pipe 51 to generate power.
[0040]
Excess fuel gas that has not been used for power generation is ejected from the upper end of the fuel gas passage 34 into the combustion chamber 37, and excess oxygen-containing gas that has not been used for power generation flows into the combustion chamber 37, Excess oxygen-containing gas reacts and burns to generate combustion gas. This combustion gas is led to the heat exchanger 41a through the combustion gas inlet 71 and discharged from the upper end of the heat exchanger 41a.
[0041]
In the fuel cell of the present invention, the fuel cell 33 is mechanically connected by the current collecting pieces 43a, 44a, 46a having the spring properties of the plate-like current collecting members 43, 44, 46, so that the fuel cell The surface contact with the cell 33 becomes larger, and the area in contact with the fuel cell 33 becomes larger than that of the conventional felt-shaped current collecting member, and the current collecting characteristics can be improved. Further, since the current collecting pieces 43a, 44a, and 46a are plate-shaped, they have a large elastic force, and even if vibration or the like occurs, sufficient contact with the fuel cell 33 can be ensured for a long time.
[0042]
In addition, since a gap is formed between the current collecting pieces 43a, 44a, and 46a, the oxygen-containing gas is supplied to the solid electrolyte 33b through the gap and the oxygen side electrode 33c, and power generation is improved.
[0043]
Furthermore, since the current collecting pieces 43a, 44a, 46a are plate-like, even when the inside of the storage container 31 becomes high temperature, it is harder to sinter than the conventional felt-shaped current collecting member, and the fuel battery cell 33 Sufficient contact with can be ensured for a long time. Further, since the current collecting members 43, 44, 46 are plate-shaped, the plate-shaped current collecting member 43, between the interconnector 33 d of one fuel battery cell 33 and the oxygen side electrode 33 c of the other fuel battery cell 33, Also when interposing 44 and 46, conduction between the oxygen side electrodes 33c of one fuel cell 33 and the other fuel cell 33 can be reliably prevented.
[0044]
In addition, surplus fuel gas and oxygen-containing gas that did not contribute to power generation are introduced into the combustion chamber 37 and reacted and burned in the combustion chamber 37, and the combustion gas and external oxygen-containing gas are converted into a heat exchanger. The heat exchanger 41a allows heat exchange between the combustion gas and the oxygen-containing gas so that the oxygen-containing gas can be preheated at the time of start-up. By inserting, the oxygen-containing gas in the oxygen-containing gas supply pipe 39 can be further heated by the combustion gas. Therefore, the fuel cell 33 is indirectly heated by the heated oxygen-containing gas to substantially generate power. Can shorten the startup time.
[0045]
Further, since the combustion chamber 37, the oxygen-containing gas storage chamber 41b, and the heat exchanger 41a are formed adjacent to each other above the fuel cell 33, the high-temperature combustion gas burned in the combustion chamber 37 is used by piping or the like. Without being introduced directly into the heat exchanger 41a, the preheating efficiency of the oxygen-containing gas can be increased with a simple structure.
[0046]
In addition, since the combustion gas and the oxygen-containing gas can be heat-exchanged in the storage container 31, there is no need to separately provide a burner for preheating the oxygen-containing gas in the storage container 31, and the combustion gas can be reduced in size. Can be used effectively.
[0047]
Further, since the oxygen-containing gas storage chamber 41b is provided in the heat exchanger 41a, the heat exchanger 41a and the oxygen-containing gas supply pipe 39 can be connected via the oxygen-containing gas storage chamber 41b. The oxygen-containing gas from 41a can be reliably supplied into the power generation chamber 49.
[0048]
The present invention is not limited to the above embodiment, the Ru can der various modifications without departing from the scope of the invention.
[0049]
Moreover, although the plate fin type | mold was used as the heat exchanger 41a, it is not limited to this in this invention, Of course, you may use another heat exchanger.
[0050]
Furthermore, in the above example, the example in which the fuel cells 33 are connected in series has been described, but it is needless to say that they may be connected in parallel. Further, although the fuel side electrode 33a is the inner electrode, the oxygen side electrode may be the inner electrode.
[0051]
【Example】
First, a NiO powder having an average particle diameter of 0.5 μm, a ZrO ₂ (YSZ) powder containing 8 mol% of Y having an average particle diameter of 0.5 μm, a pore agent, an organic binder made of PVA, and a solvent made of water The fuel-side electrode material mixed with was extruded to produce a flat fuel-side electrode molded body as shown in FIG. 2 and dried.
[0052]
Next, the YSZ powder, an organic binder made of an acrylic resin, and a solvent made of toluene are mixed to produce a sheet-like molded body, and the sheet-shaped molded body is formed into a fuel-side electrode. It was wound on the body so that both ends thereof were spaced apart at a predetermined interval by the flat portion of the fuel side electrode, and dried.
[0053]
Thereafter, a sheet-like molded body was prepared using an interconnector material in which a LaCrO ₃ -based material having an average particle diameter of 2 μm, an organic binder made of acrylic resin, and a solvent made of toluene were mixed. Between the solid electrolyte sheet-shaped molded bodies and laminated on the exposed outer surface of the fuel-side electrode molded body, and the fuel-side electrode molded body is laminated with the solid electrolyte sheet-shaped molded body and the interconnector sheet-shaped molded body. A laminated molded body was produced.
[0054]
Next, the laminated molded body was debindered and co-fired at 1500 ° C. in the air. This laminate is immersed in a paste containing La _0.6 Sr _0.4 Co _0.2 Fe _0.8 O ₃ powder having an average particle diameter of 2 μm and a solvent composed of normal paraffin, and the oxygen-side electrode molded body is dipped on the surface of the solid electrolyte. Fabricated and baked at 1150 ° C., a plurality of fuel cells as shown in FIG. 2 were fabricated.
[0055]
Then, a pair of fuel cells are arranged, and the surface of a ferritic stainless steel mainly composed of Fe and Cr is covered with Ag between the interconnector of one fuel cell and the fuel side electrode of the other fuel cell. The plate-like current collecting member of FIG. 3 in which a large number of current collecting pieces were formed on the obtained plate material was disposed with an Ag paste interposed therebetween.
[0056]
Then, with the air supplied to the outside of the fuel cell, the fuel cell in which the current collecting member is interposed is heated to 850 ° C., and the interconnector of one fuel cell and the oxygen side of the other fuel cell The electrical resistance between the electrodes was measured.
[0057]
The electrical resistance was also measured in the same manner for a comparative example in which a felt-shaped current collecting member made of ferritic stainless steel containing Fe and Cr as main components was disposed between a pair of fuel cells via an Ag paste.
[0058]
Consequently, the plate-like current collector of the present invention, whereas the very good electrical conductivity and 30Emuomegacm ² is obtained, in the comparative example using a felt-like current collecting member, 300Emuomegacm ² and electrically conducting Was low.
[0059]
【The invention's effect】
In the fuel cell of the present invention, since the fuel cell is mechanically connected by the current collecting piece having the spring property of the plate-shaped current collecting member, the fuel cell is in surface contact, and the conventional felt shape The area in contact with the fuel cell becomes larger than that of the current collecting member, and the current collecting characteristics can be improved. Further, since the current collecting piece is plate-like, the elastic force is large, and even if vibration or the like occurs, sufficient contact with the fuel cell can be ensured for a long time.
[0060]
Furthermore, since the current collecting piece is plate-shaped, it is harder to sinter than the conventional felt-shaped current collecting member even when the temperature of the storage container becomes high, and sufficient contact with the fuel cell is prolonged. A period can be secured. Furthermore, since the current collecting member is plate-shaped, for example, when the current collecting member is packed between the interconnector of one fuel cell and the outer electrode of the other fuel cell, one fuel cell And the conduction between the outer electrodes of the other fuel cell can be reliably prevented.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing a fuel cell of the present invention.
2 is a cross-sectional view showing the cell stack of FIG. 1. FIG.
FIG. 3 shows a state in which fuel cells are connected using a comb-shaped plate-like current collecting member in which a plurality of current collecting pieces are formed at one end of a base, (a) is a side view; (B) is a perspective view which shows a plate-shaped current collection member.
FIG. 4 shows a state in which fuel cells are connected using a plate-like current collecting member formed by forming a plurality of current collecting piece groups at predetermined intervals in the length direction. A side view, (b) is a perspective view which shows a plate-shaped current collection member, (c) is a perspective view which shows the plate-shaped current collection member which made the current collection piece protrude only one side.
5A and 5B are views for explaining the concept of the heat exchanger of FIG. 1, wherein FIG. 5A is a perspective view of the heat exchanger, and FIG. 5B is a corrugated plate for forming a passage for oxygen-containing gas. A perspective view and (c) are perspective views showing a corrugated plate for forming a passage of combustion gas.
FIG. 6 is a perspective view for explaining a heat exchange part of the present invention.
[Explanation of symbols]
31 ... Storage container 33 ... Fuel cell 43, 44, 46 ... Plate-like current collecting members 43a, 44a, 46a ... Current collecting pieces 43b, 44b ... Base 33a ... Fuel side Electrode (inner electrode)
33b ... Solid electrolyte 33c ... Oxygen side electrode (outer electrode)
33d ... interconnector

Claims

A plurality of columnar fuel cells having gas passage holes inside and having a flat cross section are arranged and stored in a storage container, and a plate-like current collecting member is disposed between the plurality of fuel cells and faces each other. together formed by electrically connecting the fuel cells to each other, the slits are a plurality of cuts in a part of the plate-like current collecting member is formed into a flat line, the plate-shaped current the current collecting plate between the slits A fuel cell characterized in that it protrudes alternately on both sides of the electric member and is brought into surface contact with the flat outer surface of the opposing fuel cell.

The plate-like current collecting member, a fuel cell according to claim 1, characterized in that the tooth shape plurality of said current collecting plates is formed at one end of the base portion.

The plate-like current collecting member, a fuel cell according to claim 2, characterized in that it is inserted from the base between the fuel cells to be opposed.

2. The fuel cell according to claim 1, wherein the plate-like current collecting member is formed by forming a plurality of current collecting piece groups at predetermined intervals in the length direction of the fuel cell.

In the fuel cell, a solid electrolyte and an outer electrode are sequentially formed on the surface of the inner electrode in which a gas passage hole is formed in the axial length direction, and the solid electrolyte and the outer electrode are not formed on the surface of the inner electrode. it forms the interconnector, the outer electrode of the interconnector and the other of the fuel cell of one of the fuel cell, current collecting plates of the plate-like current collecting member and wherein the abutting claims Item 5. The fuel cell according to any one of Items 1 to 4 .

The fuel cell has an outer electrode which is exposed to an oxygen-containing gas, the plate-like current collecting member, a metal or the surface of the alloy having conductivity is constructed by coating with oxidation resistant materials The fuel cell according to any one of claims 1 to 5 , wherein: