JP4727910B2

JP4727910B2 - Fuel cell

Info

Publication number: JP4727910B2
Application number: JP2003126551A
Authority: JP
Inventors: 広行田中; 成利杉田; 忠志西山; 尊基中川
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2003-05-01
Filing date: 2003-05-01
Publication date: 2011-07-20
Anticipated expiration: 2023-05-01
Also published as: JP2004335178A

Description

【０００１】
【発明の属する技術分野】
本発明は、電解質を一対の電極間に配設した電解質・電極構造体とセパレータとを積層する発電セルを備え、前記発電セルには、積層方向に貫通して反応ガス流路に連通する反応ガス連通孔および冷却媒体流路に連通する冷却媒体連通孔が設けられる内部マニホールド型燃料電池に関する。
【０００２】
【従来の技術】
例えば、固体高分子型燃料電池は、高分子イオン交換膜（陽イオン交換膜）からなる電解質（電解質膜）の両側に、それぞれアノード側電極およびカソード側電極を対設した電解質・電極構造体を、セパレータによって挟持した発電セルを備えている。この種の燃料電池は、通常、所定の数の発電セルを積層することにより、燃料電池スタックとして使用されている。
【０００３】
この発電セルにおいて、アノード側電極に供給された燃料ガス、例えば、主に水素を含有するガス（以下、水素含有ガスともいう）は、電極触媒上で水素がイオン化され、電解質を介してカソード側電極側へと移動する。その間に生じた電子は外部回路に取り出され、直流の電気エネルギとして利用される。なお、カソード側電極には、酸化剤ガス、例えば、主に酸素を含有するガスあるいは空気（以下、酸素含有ガスともいう）が供給されているために、このカソード側電極において、水素イオン、電子および酸素が反応して水が生成される。
【０００４】
上記の発電セルでは、燃料ガスおよび酸化剤ガスを気密に保持するために、種々のシール構造が採用されている。例えば、特許文献１には、従来からのＯリングによるシール構造が開示されている。すなわち、図１１に示すように、電解質膜１の両面にアノード側電極２ａおよびカソード側電極２ｂが配置された電解質膜・電極構造体３を、セパレータ４ａ、４ｂにより挟持するとともに、前記電解質膜１の周端部と前記セパレータ４ａ、４ｂとの間には、Ｏリング５ａ、５ｂが介装されている。
【０００５】
【特許文献１】
特開平８−１４８１６９号公報（段落［０００８］、図２）
【０００６】
【発明が解決しようとする課題】
通常、発電セルにおいて、セパレータの面内には、各電極に対向して反応ガスを流すための反応ガス流路が設けられるとともに、隣接する発電セルを構成するセパレータ間には、前記発電セルを冷却する冷却媒体を流すための冷却媒体流路が設けられている。反応ガスは、酸化剤ガスおよび燃料ガスであり、反応ガス流路は、カソード側電極に対向して前記酸化剤ガスを流すための酸化剤ガス流路と、アノード側電極に対向して燃料ガスを流すための燃料ガス流路とからなる。
【０００７】
さらに、セパレータの周縁部には、該セパレータの積層方向に貫通して、燃料ガス流路に連通する反応ガス連通孔である燃料ガス供給連通孔および燃料ガス排出連通孔と、酸化剤ガス流路に連通する反応ガス連通孔である酸化剤ガス供給連通孔および酸化剤ガス排出連通孔と、冷却媒体流路に連通する冷却媒体供給連通孔および冷却媒体排出連通孔とが形成されている。
【０００８】
この場合、反応ガス流路と反応ガス連通孔とは、シール部材により形成された連結流路を介して連通する構造が考えられる。例えば、図１２に示すように、セパレータ６の一方の面６ａ内には、発電面に沿って反応ガス流路７ａが形成されるとともに、積層方向に反応ガス連通孔７ｂが貫通形成されている。
【０００９】
このセパレータ６の面６ａには、シール部材８が配設されるとともに、前記シール部材８は、断続的に切り欠いた連結部８ａを備えている。この連結部８ａ間には、反応ガス流路７ａと反応ガス連通孔７ｂとを連通する連結流路７ｃが形成されている。セパレータ６の他方の面６ｂには、図示しない冷却媒体流路を密閉してシール部材９が設けられている。
【００１０】
ここで、シール部材８、９は、反応ガスおよび冷却媒体のシール機能の他に発電セル面内の荷重バランスや発電セル毎の荷重バランスを均一化させるとともに、特に発電面内を必要な面圧に保持することによって、発電性能の安定化を図る必要がある。さらに、発電セル毎の間隙を均等にして流路断面積を一定にし、反応ガス連通孔７ｂおよび冷却媒体連通孔７ｄから分配される反応ガスおよび冷却媒体の流量を均一にすることにより、各発電セル毎の発電性能の均一化および安定化を図る必要がある。
【００１１】
しかしながら、図１２の構造では、反応ガス流路７ａと反応ガス連通孔７ｂとの連結流路７ｃにおいて、シール部材８の連結部８ａが断続的に設けられる一方、シール部材９のシール片部９ａが前記連結部８ａに対向して連続的に設けられている。このため、互いに対向する連結部８ａとシール片部９ａとでは、積層方向に付与される荷重に対して、それぞれの変形量（以下、シール変形量ともいう）が異なってしまう。従って、各シール部材８、９では、それぞれのシール高さが変動して流路断面積が不均一になり、シール性の低下やガス流路の閉塞による反応ガスの供給不良等が発生するという問題がある。
【００１２】
また、薄板金属製のセパレータでは、シール線圧（荷重）のバランスが不均一になり、前記セパレータが積層方向に変形する場合がある。これにより、シール面圧や発電面圧が過剰または不足になって、簡単な構成で、所望の発電性能を発揮することができないという問題がある。
【００１３】
本発明はこの種の問題を解決するものであり、セパレータの両面に設けられるシール部材の変形量を略均一にして、所望のシール機能および発電性能を確保することが可能な燃料電池を提供することを目的とする。
【００１４】
【課題を解決するための手段】
本発明に係る燃料電池では、電解質を一対の電極間に配設した電解質・電極構造体とセパレータとを積層する複数の発電セルを備え、前記電解質・電極構造体と前記セパレータとの間に、電極面に沿って反応ガスを供給する反応ガス流路が形成されるとともに、互いに隣接する前記発電セルの各セパレータ間には、冷却媒体を供給する冷却媒体流路が形成され、前記発電セルには、積層方向に貫通して前記反応ガス流路に連通する反応ガス連通孔および前記冷却媒体流路に連通する冷却媒体連通孔が設けられる。
【００１５】
そして、セパレータの一方の面には、冷却媒体流路を密封する第１シールが設けられる一方、前記セパレータの他方の面には、反応ガス流路を密封する第２シールが設けられる。
【００１６】
この場合、第２シールは、冷却媒体流路と冷却媒体連通孔との間の連結部に断続的に設けられ、セパレータを挟んで第１シールと互いに重なり合う複数の受部を備え、前記受部と該受部に重なり合う前記第１シールのシール重合部とが、それぞれ、略同一のシール幅および略同一のバネ定数に設定されるとともに、前記複数の受部の長さの合計と前記セパレータを挟んで前記連結部に対応する箇所に位置する前記第１シールの前記シール重合部の長さとが略同一に設定されることにより、積層方向の荷重に対して積層方向の変形量が略同一に設定される。ここで、シール重合部とは、セパレータを挟んで第２シールの受部に重なり合う第１シールの一部分をいう。
【００１７】
一方、第１シールは、反応ガス流路と反応ガス連通孔との間の連結部に断続的に設けられ、セパレータを挟んで第２シールと互いに重なり合う複数の受部を備え、前記受部と該受部に重なり合う前記第２シールのシール重合部とが、それぞれ、略同一のシール幅および略同一のバネ定数に設定されるとともに、前記複数の受部の長さの合計と前記セパレータを挟んで前記連結部に対応する箇所に位置する前記第２シールの前記シール重合部の長さとが略同一に設定されることにより、積層方向の荷重に対して積層方向の変形量が略同一に設定される。ここで、シール重合部とは、セパレータを挟んで第１シールの受部に重なり合う第２シールの一部分をいう。
【００１８】
このため、セパレータの両面において、第１シールと第２シールとの変形量が略同一になり、発電セル面内の荷重分布が均一になり、発電セル毎の荷重ばらつきが減少する。従って、発電性能の安定化を図るとともに、反応ガスおよび冷却媒体の流量が均一化され、各発電セル毎の発電性能の均一化および安定化を図ることができる。
【００１９】
また、本発明の請求項３に係る燃料電池では、電解質・電極構造体は、電解質膜を第１および第２の電極で挟持するとともに、前記第１の電極が前記第２の電極よりも小さな表面積に設定されており、所謂、段差ＭＥＡを構成している。
【００２０】
そして、第１シールは、第１の電極側の前記セパレータに設けられるとともに、電解質膜とセパレータとの間に配置される内側シールと、隣接するセパレータ間に配置される外側シールとを設ける。一方、第２シールは、第１シールの内側シールに対応する内側シールと、前記第１シールの外側シールに対応する外側シールとを設ける。これにより、発電セルの強度の向上を図るとともに、前記発電セル自体の薄型化が可能になる。
【００２１】
さらに、受部とシール重合部とは、それぞれ略同一のシール線圧に設定される。シール線圧とは、単位長さ当たりの荷重をいう。これにより、簡単な構成で、発電セル内および各発電セル間の間隙が均等になって、安定した反応ガスおよび冷却媒体の連結（連通）機能とシール機能とを確保することができる。
【００２２】
さらにまた、受部は、シール重合部と交差する方向に延在するシール長さが、前記シール重合部のシール幅寸法よりも長尺に構成されている。このため、簡単な構成で、第１および第２シールの変形量を略同一に設定することが可能になる。
【００２３】
【発明の実施の形態】
図１は、本発明の実施形態に係る燃料電池１０を構成する発電セル１２の要部分解斜視説明図であり、図２は、複数の発電セル１２を矢印Ａ方向に積層してスタック化された燃料電池１０の要部断面説明図である。
【００２４】
図２および図３に示すように、燃料電池１０は、複数の発電セル１２を矢印Ａ方向に積層するとともに、積層方向両端にエンドプレート１４ａ、１４ｂが配置される。エンドプレート１４ａ、１４ｂは、図示しないタイロッドを介して固定されることにより、積層されている発電セル１２には、矢印Ａ方向に所定の締め付け荷重が付与される。
【００２５】
図１に示すように、発電セル１２は、電解質膜・電極構造体（電解質・電極構造体）１６が、第１および第２金属セパレータ１８、２０に挟持されて構成される。第１および第２金属セパレータ１８、２０は、例えば、鋼板、ステンレス鋼板、アルミニウム板、めっき処理鋼板、あるいはその金属表面に防食用の表面処理を施した金属板により構成されており、厚さが、例えば、０．０５ｍｍ〜１．０ｍｍの範囲内に設定されている。
【００２６】
発電セル１２の矢印Ｂ方向（図１中、水平方向）の一端縁部には、積層方向である矢印Ａ方向に互いに連通して、酸化剤ガス、例えば、酸素含有ガスを供給するための酸化剤ガス入口連通孔３０ａ、冷却媒体を排出するための冷却媒体出口連通孔３２ｂ、および燃料ガス、例えば、水素含有ガスを排出するための燃料ガス出口連通孔３４ｂが、矢印Ｃ方向（鉛直方向）に配列して設けられる。
【００２７】
発電セル１２の矢印Ｂ方向の他端縁部には、矢印Ａ方向に互いに連通して、燃料ガスを供給するための燃料ガス入口連通孔３４ａ、冷却媒体を供給するための冷却媒体入口連通孔３２ａ、および酸化剤ガスを排出するための酸化剤ガス出口連通孔３０ｂが、矢印Ｃ方向に配列して設けられる。
【００２８】
電解質膜・電極構造体１６は、例えば、パーフルオロスルホン酸の薄膜に水が含浸された固体高分子電解質膜３６と、前記固体高分子電解質膜３６を挟持するアノード側電極３８およびカソード側電極４０とを備える。アノード側電極３８は、カソード側電極４０よりも小さな表面積を有している。
【００２９】
アノード側電極３８およびカソード側電極４０は、カーボンペーパ等からなるガス拡散層と、白金合金が表面に担持された多孔質カーボン粒子が前記ガス拡散層の表面に一様に塗布された電極触媒層とを有する。電極触媒層は、固体高分子電解質膜３６の両面に接合されている。
【００３０】
第１金属セパレータ１８の電解質膜・電極構造体１６側の面１８ａには、例えば、矢印Ｂ方向に蛇行しながら鉛直上方向に延在する酸化剤ガス流路（反応ガス流路）４２が設けられる（図１および図４参照）。図５に示すように、第２金属セパレータ２０の電解質膜・電極構造体１６側の面２０ａには、後述するように、燃料ガス入口連通孔３４ａと燃料ガス出口連通孔３４ｂとに連通し、矢印Ｂ方向に蛇行しながら鉛直上方向（矢印Ｃ方向）に延在する燃料ガス流路（反応ガス流路）４４が形成される。
【００３１】
図１および図６に示すように、第１金属セパレータ１８の面１８ｂと第２金属セパレータ２０の面２０ｂとの間には、冷却媒体入口連通孔３２ａと冷却媒体出口連通孔３２ｂとに連通する冷却媒体流路４６が形成される。この冷却媒体流路４６は、矢印Ｂ方向に直線状に延在する。
【００３２】
図１および図４に示すように、第１金属セパレータ１８の面１８ａ、１８ｂには、この第１金属セパレータ１８の外周端部を周回して、第１シール部材５０が一体化される。第１シール部材５０は、例えば、ＥＰＤＭ、ＮＢＲ、フッ素ゴム、シリコーンゴム、フロロシリコーンゴム、ブチルゴム、天然ゴム、スチレンゴム、クロロプレーン、またはアクリルゴム等のシール材、クッション材、あるいはパッキン材を使用する。
【００３３】
第１シール部材５０は、第１金属セパレータ１８の面１８ａに一体化される第１平面部５２と、前記第１金属セパレータ１８の面１８ｂに一体化される第２平面部５４とを備える。第２平面部５４は、第１平面部５２よりも長尺に構成される。
【００３４】
図２に示すように、第１平面部５２は、電解質膜・電極構造体１６の外周端部から外部に離間した位置を周回する一方、第２平面部５４は、カソード側電極４０に所定の範囲にわたって重合する位置を周回する。図４に示すように、第１平面部５２は、酸化剤ガス入口連通孔３０ａおよび酸化剤ガス出口連通孔３０ｂを酸化剤ガス流路４２に連通して形成される一方、第２平面部５４は、冷却媒体入口連通孔３２ａと冷却媒体出口連通孔３２ｂとを連通して形成される。
【００３５】
第２金属セパレータ２０の面２０ａ、２０ｂには、この第２金属セパレータ２０の外周端部を周回して、第２シール部材５６が一体化される。この第２シール部材５６は、第２金属セパレータ２０の外周端部に近接して面２０ａに設けられる外側シール（第１シール）５８ａを備え、この外側シール５８ａから内方に所定の距離だけ離間して内側シール（第１シール）５８ｂが設けられる。
【００３６】
外側シール５８ａおよび内側シール５８ｂは、先端先細り形状（リップ形状）、台形状または蒲鉾形状等、種々の形状に選択可能である。外側シール５８ａは、第１金属セパレータ１８に設けられている第１平面部５２に接触する一方、内側シール５８ｂは、電解質膜・電極構造体１６を構成する固体高分子電解質膜３６に直接接触する。
【００３７】
図５に示すように、外側シール５８ａは、酸化剤ガス入口連通孔３０ａ、冷却媒体出口連通孔３２ｂ、燃料ガス出口連通孔３４ｂ、燃料ガス入口連通孔３４ａ、冷却媒体入口連通孔３２ａおよび酸化剤ガス出口連通孔３０ｂを囲繞する。内側シール５８ｂは、燃料ガス流路４４を囲繞するとともに、前記内側シール５８ｂと外側シール５８ａとの間には、電解質膜・電極構造体１６の外周端部が配置される。
【００３８】
第２金属セパレータ２０の面２０ｂには、外側シール５８ａに対応する外側シール（第２シール）５８ｃと、内側シール５８ｂに対応する内側シール（第２シール）５８ｄとが設けられる（図６参照）。外側シール５８ｃおよび内側シール５８ｄは、上記の外側シール５８ａおよび内側シール５８ｂと同様の形状を有している。
【００３９】
図５に示すように、外側シール５８ａは、酸化剤ガス入口連通孔３０ａと酸化剤ガス流路４２とを連通する入口連結部６０と、酸化剤ガス出口連通孔３０ｂと前記酸化剤ガス流路４２とを連通させる出口連結部６２とを備える。
【００４０】
入口連結部６０は、外側シール５８ａを矢印Ｃ方向に沿って断続的に切り欠くとともに、矢印Ｂ方向に延在する複数の受部６４により構成される。各受部６４間には、酸化剤ガス用の連通路が形成される。出口連結部６２は、同様に外側シール５８ａを部分的に切り欠くとともに、矢印Ｂ方向に延在する複数の受部６６を備える。各受部６６間には、酸化剤ガス用の連通路が形成される。
【００４１】
図７に示すように、入口連結部６０の受部６４と外側シール５８ｃのシール重合部６８とは、第２金属セパレータ２０の両面２０ａ、２０ｂで互いに重なり合っている。シール重合部６８とは、第２金属セパレータ２０を挟んで外側シール５８ａの受部６４に重なり合う外側シール５８ｃの一部分をいう。受部６４は、シール重合部６８と交差する方向に延在しかつ前記シール重合部６８のシール幅寸法、すなわち、外側シール５８ｃのシール幅寸法よりも長尺に構成されており、前記受部６４と前記シール重合部６８とは、積層方向の荷重に対して積層方向のシール変形量が略同一に設定される。
【００４２】
具体的には、各受部６４とシール重合部６８とは、略同一の単位長さ当たりの荷重、すなわち、シール線圧を有するとともに、前記受部６４のシール長さＬ１とシール重合部６８のシール長さＬ２とは、略同一の長さに設定される。このシール長さＬ２は、各受部６４の配置間隔に相当するシール重合部６８の長さである。なお、受部６４とシール重合部６８とは、バネ定数が略同一であれば同一の材料で形成される必要はなく、種々の材料が選択可能である。
【００４３】
出口連結部６２は、上記の入口連結部６０と同様に構成されており、第２金属セパレータ２０の両面２０ａ、２０ｂで互いに重なり合う各受部６４と外側シール５８ｃのシール重合部７０とは、積層方向の荷重に対して積層方向のシール変形量が略同一に設定される（図５参照）。
【００４４】
図６に示すように、第２金属セパレータ２０の面２０ｂには、冷却媒体入口連通孔３２ａと冷却媒体流路４６とを連通する入口連結部７２と、冷却媒体出口連通孔３２ｂと前記冷却媒体流路４６とを連通する出口連結部７４とが設けられる。入口連結部７２は、外側シール５８ｃおよび内側シール５８ｄを構成して矢印Ｃ方向に断続的に設けられるとともに、矢印Ｂ方向に延在する複数の受部７６を備える。出口連結部７４は、同様に、外側シール５８ｃおよび内側シール５８ｄを構成して矢印Ｃ方向に断続的に設けられるとともに、矢印Ｂ方向に延在する複数の受部７８を備える。
【００４５】
図８に示すように、入口連結部７２は、面２０ａの外側シール５８ａおよび内側シール５８ｂを構成するシール重合部８０ａ、８０ｂと、第２金属セパレータ２０を介装して重なり合っている。入口連結部７２を構成する各受部７６とシール重合部８０ａ、８０ｂとは、積層方向の荷重に対して積層方向のシール変形量が略同一に設定される。具体的には、受部７６のシール長さＬ３は、シール重合部８０ａ、８０ｂのそれぞれのシール長さＬ４、Ｌ５を加算した値と等しく設定される（Ｌ３＝Ｌ４＋Ｌ５）。このシール長さＬ４、Ｌ５は、各受部７６の配置間隔に相当するシール重合部８０ａ、８０ｂの長さである。なお、受部７６は、シール重合部８０ａ、８０ｂに一体的に跨って設けられているが、各シール重合部８０ａ、８０ｂ毎に分割して構成してもよい。
【００４６】
同様に、出口連結部７４を構成する各受部７８は、図６に示すように、第２金属セパレータ２０の両面２０ａ、２０ｂで外側シール５８ａおよび内側シール５８ｂのシール重合部８２ａ、８２ｂと重なり合っている。受部７８とシール重合部８２ａ、８２ｂとは、積層方向の荷重に対して積層方向のシール変形量が略同一に設定される。
【００４７】
図６に示すように、面２０ｂでは、燃料ガス入口連通孔３４ａおよび燃料ガス出口連通孔３４ｂの近傍に、入口連結部８４および出口連結部８６が設けられる。入口連結部８４は、矢印Ｃ方向に配列される複数の受部８８を設ける一方、出口連結部８６は、同様に矢印Ｃ方向に配列される複数の受部９０を備える。
【００４８】
各受部８８は、第２金属セパレータ２０を挟んで外側シール５８ａおよび内側シール５８ｂのシール重合部９２ａ、９２ｂと重なり合っている。各受部９０は、同様に第２金属セパレータ２０を挟んで外側シール５８ａおよび内側シール５８ｂのシール重合部９４ａ、９４ｂと重なり合っている。
【００４９】
入口連結部８４とシール重合部９２ａ、９２ｂおよび出口連結部８６とシール重合部９４ａ、９４ｂは、それぞれ積層方向の荷重に対して積層方向のシール変形量が略同一に設定され、具体的には、入口連結部７２と同様の構成を有している。入口連結部８４および出口連結部８６の近傍には、内側シール５８ｄの外方に位置して、それぞれ複数の供給孔部９６および排出孔部９８が形成される。供給孔部９６と排出孔部９８は、第２金属セパレータ２０の面２０ａで内側シール５８ｂの内方にかつ燃料ガス流路４４の入口側と出口側とに貫通形成される（図５参照）。
【００５０】
このように構成される燃料電池１０の動作について、以下に説明する。
【００５１】
まず、図１に示すように、燃料ガス入口連通孔３４ａに水素含有ガス等の燃料ガスが供給されるとともに、酸化剤ガス入口連通孔３０ａに酸素含有ガス等の酸化剤ガスが供給される。さらに、冷却媒体入口連通孔３２ａに純水やエチレングリコール、オイル等の冷却媒体が供給される。
【００５２】
このため、酸化剤ガスは、酸化剤ガス入口連通孔３０ａから第１金属セパレータ１８の酸化剤ガス流路４２に導入され（図３参照）、矢印Ｂ方向に蛇行しながら鉛直上方向に移動して電解質膜・電極構造体１６を構成するカソード側電極４０に供給される。一方、燃料ガスは、燃料ガス入口連通孔３４ａから供給孔部９６を通って第２金属セパレータ２０の燃料ガス流路４４に導入され（図２参照）、矢印Ｂ方向に蛇行しながら鉛直上方向に移動して電解質膜・電極構造体１６を構成するアノード側電極３８に供給される。
【００５３】
従って、各電解質膜・電極構造体１６では、カソード側電極４０に供給される酸化剤ガスと、アノード側電極３８に供給される燃料ガスとが、電極触媒層内で電気化学反応により消費されて発電が行われる。
【００５４】
次いで、アノード側電極３８に供給されて消費された燃料ガスは、排出孔部９８を通り燃料ガス出口連通孔３４ｂに沿って矢印Ａ方向に排出される。同様に、カソード側電極４０に供給されて消費された酸化剤ガスは、酸化剤ガス出口連通孔３０ｂに沿って矢印Ａ方向に排出される。
【００５５】
また、冷却媒体入口連通孔３２ａに供給された冷却媒体は、第１および第２金属セパレータ１８、２０間の冷却媒体流路４６に導入された後、矢印Ｂ方向に流通する。この冷却媒体は、電解質膜・電極構造体１６を冷却した後、冷却媒体出口連通孔３２ｂから排出される。
【００５６】
この場合、本実施形態では、酸化剤ガス入口連通孔３０ａから酸化剤ガス流路４２に酸化剤ガスを供給するために、第２金属セパレータ２０の面２０ａには、複数の受部６４を備えた入口連結部６０が設けられている。図５に示すように、この入口連結部６０は、外側シール５８ａの一部を構成しており、前記第２金属セパレータ２０の面２０ｂには、前記入口連結部６０の受部６４と互いに重なり合うシール重合部６８が設けられる。このシール重合部６８は、外側シール５８ｃの一部を構成しており、前記シール重合部６８および受部６４は、弾性を有して変形し易い。
【００５７】
そこで、図７に示すように、入口連結部６０の各受部６４とシール重合部６８とは、略同一のシール線圧を有するとともに、前記受部６４のシール長さＬ１とシール重合部６８のシール長さＬ２とは、略同一の長さに設定されている。このため、第２金属セパレータ２０の両面２０ａ、２０ｂで互いに重なり合う各受部６４とシール重合部６８とは、積層方向の荷重に対して積層方向のシール変形量が略同一に維持される。
【００５８】
具体的には、受部６４のシール長さＬ１とシール重合部６８のシール長さＬ２とを、図９に示すように変化させたところ、積層方向の荷重に対してシール長さＬ１とシール長さＬ２との比（Ｌ１／Ｌ２）に対する前記受部６４と前記シール重合部６８との圧縮高さの差が、図１０に示すように変動した。従って、シール長さＬ１とシール長さＬ２との比が略１．０、すなわち、シール長さＬ１＝シール長さＬ２の関係を満たすことによって、圧縮高さに差が生ずることがない。
【００５９】
これにより、第２金属セパレータ２０では、両面２０ａ、２０ｂにおけるシール変形量が略同一となり、前記第２金属セパレータ２０に対してシール線圧（荷重）のバランスが不均一となることがなく、該第２金属セパレータ２０自体の変形を良好に阻止することが可能になる。しかも、入口連結部６０に変形が惹起されることがなく、酸化剤ガス入口連通孔３０ａから酸化剤ガス流路４２に酸化剤ガスを円滑かつ確実に供給することができる。
【００６０】
一方、出口連結部６２では、上記の入口連結部６０と同様に、各受部６６とシール重合部７０とのシール変形量が略同一となる。このため、第２金属セパレータ２０自体の変形を阻止するとともに、酸化剤ガス流路４２から酸化剤ガス出口連通孔３０ｂに排ガス（使用済み酸化剤ガス）を確実に排出することが可能になる。
【００６１】
また、図６に示すように、第２金属セパレータ２０の面２０ｂには、冷却媒体入口連通孔３２ａと冷却媒体流路４６とを連通する入口連結部７２が設けられる。この入口連結部７２の各受部７６と、該受部７６に第２金属セパレータ２０を介装して互いに重なり合うシール重合部８０ａ、８０ｂとは、積層方向の荷重に対して積層方向のシール変形量が略同一に設定されている。すなわち、図８に示すように、受部７６のシール長さＬ３が各シール重合部８０ａ、８０ｂのシール長さＬ４、Ｌ５の加算値と等しくなっている（Ｌ３＝Ｌ４＋Ｌ５）。
【００６２】
これにより、入口連結部７２とシール重合部８０ａ、８０ｂとのシール変形量が略同一となり、第２金属セパレータ２０自体の変形を阻止するとともに、冷却媒体入口連通孔３２ａから冷却媒体流路４６に冷却媒体を円滑かつ確実に供給することができる。
【００６３】
一方、出口連結部７４においても同様に、各受部７８とシール重合部８２ａ、８２ｂとのシール変形量が略同一となって、冷却媒体を冷却媒体出口連通孔３２ｂに円滑に排出することが可能になる。
【００６４】
さらにまた、図６に示すように、燃料ガス入口連通孔３４ａおよび燃料ガス出口連通孔３４ｂと燃料ガス流路４４とを連通する入口連結部８４および出口連結部８６が設けられている。そして、それぞれの受部８８、９０とシール重合部９２ａ、９２ｂおよび９４ａ、９４ｂとは、シール変形量が略同一に設定されており、燃料ガスの円滑な供給および排出と、第２金属セパレータ２０自体の変形の阻止とが、良好に行われる。
【００６５】
これにより、本実施形態では、燃料電池１０の発電性能の安定化を図るとともに、簡単な構成で、燃料ガス、酸化剤ガスおよび冷却媒体の流量が均一化され、各発電セル１２毎の発電性能の均一化および安定化が確実に図られるという効果が得られる。
【００６６】
【発明の効果】
本発明に係る燃料電池では、第２シールは、冷却媒体流路と冷却媒体連通孔との間に断続的に設けられ、セパレータを挟んで第１シールのシール重合部と互いに重なり合う複数の受部を備え、前記受部と該受部に重なり合う前記シール重合部とは、積層方向の荷重に対して変形量が略同一に設定される。
【００６７】
一方、第１シールは、反応ガス流路と反応ガス連通孔との間に断続的に設けられ、セパレータを挟んで第２シールのシール重合部と互いに重なり合う複数の受部を備え、前記受部と該受部に重なり合う前記シール重合部とは、積層方向の荷重に対して変形量が略同一に設定される。
【００６８】
このため、セパレータの両面において、第１シールと第２シールとの変形量が略同一になり、発電セル面内の荷重バランスおよび発電セル毎の荷重バランスが均一化される。従って、発電性能の安定化を図るとともに、反応ガスおよび冷却媒体の流量が均一化され、各発電セル毎の発電性能の均一化および安定化を図ることができる。
【図面の簡単な説明】
【図１】本発明の実施形態に係る燃料電池を構成する発電セルの要部分解斜視説明図である。
【図２】前記燃料電池の要部断面説明図である。
【図３】前記燃料電池の他の部位の要部断面説明図である。
【図４】前記発電セルを構成する第１金属セパレータの正面説明図である。
【図５】前記発電セルを構成する第２金属セパレータの一方の面の正面説明図である。
【図６】前記発電セルを構成する第２金属セパレータの他方の面の正面説明図である。
【図７】前記発電セルに設けられた酸化剤ガスの入口連結部の説明図である。
【図８】前記発電セルに設けられた冷却媒体の入口連結部の説明図である。
【図９】シール長さと受部の長さとの関係図である。
【図１０】シール長さと受部の長さと比による圧縮高さの差の説明図である。
【図１１】特許文献１に開示されたシール構造の説明図である。
【図１２】従来のセパレータの一部説明図である。
【符号の説明】
１０…燃料電池１２…発電セル
１６…電解質膜・電極構造体１８、２０…金属セパレータ
３０ａ…酸化剤ガス入口連通孔３０ｂ…酸化剤ガス出口連通孔
３２ａ…冷却媒体入口連通孔３２ｂ…冷却媒体出口連通孔
３４ａ…燃料ガス入口連通孔３４ｂ…燃料ガス出口連通孔
３６…固体高分子電解質膜３８…アノード側電極
４０…カソード側電極４２…酸化剤ガス流路
４４…燃料ガス流路４６…冷却媒体流路
５０、５６…シール部材５２、５４…平面部
５８ａ、５８ｃ…外側シール５８ｂ、５８ｄ…内側シール
６０、７２、８４…入口連結部６２、７４、８６…出口連結部
６４、６６、７６、７８、８８、９０…受部
６８、７０、８０ａ、８０ｂ、８２ａ、８２ｂ、９２ａ、９２ｂ、９４ａ、９４ｂ…シール重合部
９６…供給孔部９８…排出孔部[0001]
BACKGROUND OF THE INVENTION
The present invention includes a power generation cell in which an electrolyte / electrode structure in which an electrolyte is disposed between a pair of electrodes and a separator are stacked, and the power generation cell penetrates in a stacking direction and communicates with a reaction gas channel. The present invention relates to an internal manifold fuel cell provided with a gas communication hole and a cooling medium communication hole communicating with a cooling medium flow path.
[0002]
[Prior art]
For example, a polymer electrolyte fuel cell has an electrolyte / electrode structure in which an anode electrode and a cathode electrode are respectively provided on both sides of an electrolyte (electrolyte membrane) made of a polymer ion exchange membrane (cation exchange membrane). A power generation cell sandwiched between separators is provided. This type of fuel cell is normally used as a fuel cell stack by stacking a predetermined number of power generation cells.
[0003]
In this power generation cell, the fuel gas supplied to the anode side electrode, for example, a gas mainly containing hydrogen (hereinafter also referred to as a hydrogen-containing gas) is ionized with hydrogen on the electrode catalyst, and the cathode side passes through the electrolyte. Move to the electrode side. Electrons generated during that time are taken out to an external circuit and used as direct current electric energy. The cathode side electrode is supplied with an oxidant gas, for example, a gas mainly containing oxygen or air (hereinafter also referred to as an oxygen-containing gas). And oxygen react to produce water.
[0004]
In the above power generation cell, various seal structures are employed in order to keep the fuel gas and the oxidant gas airtight. For example, Patent Document 1 discloses a conventional seal structure using an O-ring. That is, as shown in FIG. 11, the electrolyte membrane / electrode structure 3 in which the anode-side electrode 2a and the cathode-side electrode 2b are disposed on both surfaces of the electrolyte membrane 1 is sandwiched by separators 4a and 4b, and the electrolyte membrane 1 O-rings 5a and 5b are interposed between the peripheral ends of the separators 4a and 4b.
[0005]
[Patent Document 1]
JP-A-8-148169 (paragraph [0008], FIG. 2)
[0006]
[Problems to be solved by the invention]
Usually, in a power generation cell, a reaction gas flow path for flowing a reaction gas is provided in the plane of the separator so as to face each electrode, and the power generation cell is interposed between separators constituting adjacent power generation cells. A cooling medium flow path for flowing a cooling medium to be cooled is provided. The reactive gas is an oxidant gas and a fuel gas, and the reactive gas flow path is an oxidant gas flow path for flowing the oxidant gas facing the cathode side electrode, and a fuel gas facing the anode side electrode. And a fuel gas flow path for flowing gas.
[0007]
Furthermore, a fuel gas supply communication hole and a fuel gas discharge communication hole, which are reaction gas communication holes that penetrate the separator in the stacking direction and communicate with the fuel gas flow channel, and an oxidant gas flow channel An oxidant gas supply communication hole and an oxidant gas discharge communication hole, which are reaction gas communication holes communicating with each other, and a cooling medium supply communication hole and a cooling medium discharge communication hole communicating with the cooling medium flow path are formed.
[0008]
In this case, a structure in which the reaction gas channel and the reaction gas communication hole communicate with each other via a connection channel formed by a seal member is conceivable. For example, as shown in FIG. 12, in one surface 6a of the separator 6, a reaction gas flow path 7a is formed along the power generation surface, and a reaction gas communication hole 7b is formed to penetrate in the stacking direction. .
[0009]
A seal member 8 is disposed on the surface 6a of the separator 6, and the seal member 8 includes a connecting portion 8a that is intermittently cut out. A connecting channel 7c that communicates the reaction gas channel 7a and the reaction gas communication hole 7b is formed between the connecting portions 8a. A seal member 9 is provided on the other surface 6 b of the separator 6 so as to seal a cooling medium flow path (not shown).
[0010]
Here, the seal members 8 and 9 make the load balance in the power generation cell plane and the load balance for each power generation cell uniform in addition to the sealing function of the reaction gas and the cooling medium, and particularly the required surface pressure in the power generation plane. Therefore, it is necessary to stabilize the power generation performance. Further, the gap between the power generation cells is made uniform, the flow path cross-sectional area is made constant, and the flow rates of the reaction gas and the cooling medium distributed from the reaction gas communication hole 7b and the cooling medium communication hole 7d are made uniform. It is necessary to equalize and stabilize the power generation performance of each cell.
[0011]
However, in the structure of FIG. 12, in the connection flow path 7c between the reaction gas flow path 7a and the reaction gas communication hole 7b, the connection portion 8a of the seal member 8 is provided intermittently, while the seal piece 9a of the seal member 9 is provided. Is continuously provided facing the connecting portion 8a. For this reason, the amount of deformation (hereinafter also referred to as the amount of seal deformation) differs between the coupling portion 8a and the seal piece portion 9a facing each other with respect to the load applied in the stacking direction. Therefore, in each of the seal members 8 and 9, the respective seal heights fluctuate and the cross-sectional area of the flow path becomes non-uniform, resulting in a poor supply of reaction gas due to a decrease in sealing performance or a blockage of the gas flow path. There's a problem.
[0012]
Moreover, in the separator made of a thin metal plate, the balance of the seal linear pressure (load) becomes uneven, and the separator may be deformed in the stacking direction. As a result, the seal surface pressure and the power generation surface pressure become excessive or insufficient, and there is a problem that the desired power generation performance cannot be exhibited with a simple configuration.
[0013]
The present invention solves this type of problem, and provides a fuel cell capable of ensuring a desired sealing function and power generation performance by making the deformation amount of sealing members provided on both sides of a separator substantially uniform. For the purpose.
[0014]
[Means for Solving the Problems]
Main departure Clearly In such a fuel cell, an electrolyte / electrode structure in which an electrolyte is disposed between a pair of electrodes and a separator are stacked. plural A reaction gas flow path that supplies a reaction gas along the electrode surface is formed between the electrolyte / electrode structure and the separator, including a power generation cell, Next to each other The power generation cell Each separator Between Is A cooling medium flow path for supplying a cooling medium is formed, and the power generation cell has a reaction gas communication hole penetrating in the stacking direction and communicating with the reaction gas flow path, and a cooling medium communication hole communicating with the cooling medium flow path. Is provided.
[0015]
A first seal that seals the cooling medium flow path is provided on one surface of the separator, and a second seal that seals the reaction gas flow path is provided on the other surface of the separator.
[0016]
In this case, the second seal is between the cooling medium flow path and the cooling medium communication hole. Connecting part A plurality of receiving portions that are intermittently provided and overlap the first seal across the separator, the receiving portion and the seal overlapping portion of the first seal overlapping the receiving portion, But ,Respectively , Set to approximately the same seal width and approximately the same spring constant In addition, the total length of the plurality of receiving portions and the length of the seal overlapping portion of the first seal located at a location corresponding to the connecting portion across the separator are set to be substantially the same. Accordingly, the deformation amount in the stacking direction is set to be substantially the same with respect to the load in the stacking direction. Here, the seal overlapping portion refers to a part of the first seal that overlaps the receiving portion of the second seal with the separator interposed therebetween.
[0017]
On the other hand, the first seal is between the reaction gas flow path and the reaction gas communication hole. Connecting part A plurality of receiving portions that are intermittently provided and overlap the second seal across the separator, and the receiving portion and the seal overlapping portion of the second seal overlapping the receiving portion; But ,Respectively , Set to approximately the same seal width and approximately the same spring constant In addition, the total length of the plurality of receiving portions and the length of the seal overlapping portion of the second seal located at a location corresponding to the connecting portion across the separator are set to be substantially the same. Accordingly, the deformation amount in the stacking direction is set to be substantially the same with respect to the load in the stacking direction. Here, the seal overlapping portion refers to a part of the second seal that overlaps the receiving portion of the first seal with the separator interposed therebetween.
[0018]
For this reason, the deformation amounts of the first seal and the second seal are substantially the same on both surfaces of the separator, the load distribution in the power generation cell surface becomes uniform, and the load variation for each power generation cell is reduced. Therefore, the power generation performance can be stabilized, the flow rates of the reaction gas and the cooling medium can be made uniform, and the power generation performance for each power generation cell can be made uniform and stable.
[0019]
In the fuel cell according to claim 3 of the present invention, the electrolyte / electrode structure includes an electrolyte membrane sandwiched between the first and second electrodes, and the first electrode is smaller than the second electrode. It is set to a surface area and constitutes a so-called step MEA.
[0020]
And the first seal is Provided in the separator on the first electrode side; An inner seal disposed between the electrolyte membrane and the separator and an outer seal disposed between adjacent separators are provided. On the other hand, the second seal corresponds to the inner seal corresponding to the inner seal of the first seal and the outer seal of the first seal. Outside With side seal The Thereby, while improving the intensity | strength of a power generation cell, the said power generation cell itself can be reduced in thickness.
[0021]
further , Received Part and seal overlap part are approximately the same seal wire To pressure Is set. Seal linear pressure refers to the load per unit length. Thus, with a simple configuration, the gaps in the power generation cells and between the power generation cells are equalized, and a stable reaction gas and cooling medium connection (communication) function and a sealing function can be ensured.
[0022]
Furthermore , Received Part extends in the direction intersecting with the seal overlap part The seal length to be It is longer than the seal width dimension of the seal overlap portion. For this reason, it is possible to set the deformation amounts of the first and second seals to be substantially the same with a simple configuration.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an exploded perspective view of a main part of a power generation cell 12 constituting a fuel cell 10 according to an embodiment of the present invention, and FIG. 2 is a stack in which a plurality of power generation cells 12 are stacked in the direction of arrow A. 2 is a cross-sectional explanatory view of a main part of the fuel cell 10.
[0024]
As shown in FIGS. 2 and 3, the fuel cell 10 has a plurality of power generation cells 12 stacked in the direction of arrow A, and end plates 14a and 14b are disposed at both ends in the stacking direction. The end plates 14a and 14b are fixed via tie rods (not shown), whereby a predetermined tightening load is applied to the stacked power generation cells 12 in the arrow A direction.
[0025]
As shown in FIG. 1, the power generation cell 12 includes an electrolyte membrane / electrode structure (electrolyte / electrode structure) 16 sandwiched between first and second metal separators 18 and 20. The first and second metal separators 18 and 20 are made of, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a metal plate whose surface is subjected to anticorrosion treatment, and has a thickness of For example, it is set within a range of 0.05 mm to 1.0 mm.
[0026]
One end edge of the power generation cell 12 in the direction of arrow B (the horizontal direction in FIG. 1) communicates with each other in the direction of arrow A, which is the stacking direction, and oxidant for supplying an oxidant gas, eg, an oxygen-containing gas An agent gas inlet communication hole 30a, a cooling medium outlet communication hole 32b for discharging a cooling medium, and a fuel gas outlet communication hole 34b for discharging a fuel gas, for example, a hydrogen-containing gas, are provided in the arrow C direction (vertical direction). Are provided in an array.
[0027]
The other end edge of the power generation cell 12 in the direction of arrow B communicates with each other in the direction of arrow A, a fuel gas inlet communication hole 34a for supplying fuel gas, and a cooling medium inlet communication hole for supplying a cooling medium. 32a and an oxidant gas outlet communication hole 30b for discharging the oxidant gas are arranged in the direction of arrow C.
[0028]
The electrolyte membrane / electrode structure 16 includes, for example, a solid polymer electrolyte membrane 36 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side electrode 38 and a cathode side electrode 40 that sandwich the solid polymer electrolyte membrane 36. With. The anode side electrode 38 has a smaller surface area than the cathode side electrode 40.
[0029]
The anode side electrode 38 and the cathode side electrode 40 include a gas diffusion layer made of carbon paper or the like, and an electrode catalyst layer in which porous carbon particles having a platinum alloy supported on the surface are uniformly applied to the surface of the gas diffusion layer. And have. The electrode catalyst layer is bonded to both surfaces of the solid polymer electrolyte membrane 36.
[0030]
On the surface 18a of the first metal separator 18 on the electrolyte membrane / electrode structure 16 side, for example, an oxidant gas flow path (reactive gas flow path) 42 extending in the vertical direction while meandering in the direction of arrow B is provided. (See FIGS. 1 and 4). As shown in FIG. 5, the surface 20a of the second metal separator 20 on the electrolyte membrane / electrode structure 16 side communicates with a fuel gas inlet communication hole 34a and a fuel gas outlet communication hole 34b, as will be described later. A fuel gas channel (reactive gas channel) 44 extending in the vertical upward direction (arrow C direction) while meandering in the direction of arrow B is formed.
[0031]
As shown in FIGS. 1 and 6, the cooling medium inlet communication hole 32 a and the cooling medium outlet communication hole 32 b are communicated between the surface 18 b of the first metal separator 18 and the surface 20 b of the second metal separator 20. A cooling medium flow path 46 is formed. The cooling medium flow path 46 extends linearly in the direction of arrow B.
[0032]
As shown in FIGS. 1 and 4, the first seal member 50 is integrated with the surfaces 18 a and 18 b of the first metal separator 18 around the outer peripheral end of the first metal separator 18. The first seal member 50 uses, for example, a seal material such as EPDM, NBR, fluorine rubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroplane, or acrylic rubber, a cushion material, or a packing material. To do.
[0033]
The first seal member 50 includes a first flat portion 52 that is integrated with the surface 18 a of the first metal separator 18, and a second flat portion 54 that is integrated with the surface 18 b of the first metal separator 18. The second plane part 54 is configured to be longer than the first plane part 52.
[0034]
As shown in FIG. 2, the first flat portion 52 circulates at a position spaced outside from the outer peripheral end of the electrolyte membrane / electrode structure 16, while the second flat portion 54 has a predetermined contact with the cathode side electrode 40. Circulate the position where polymerization occurs over a range. As shown in FIG. 4, the first flat portion 52 is formed by connecting the oxidant gas inlet communication hole 30 a and the oxidant gas outlet communication hole 30 b to the oxidant gas flow path 42, while the second flat portion 54. Is formed by communicating the cooling medium inlet communication hole 32a and the cooling medium outlet communication hole 32b.
[0035]
The second seal member 56 is integrated with the surfaces 20 a and 20 b of the second metal separator 20 around the outer peripheral end of the second metal separator 20. The second seal member 56 includes an outer seal (first seal) 58a provided on the surface 20a adjacent to the outer peripheral end of the second metal separator 20, and is spaced apart from the outer seal 58a by a predetermined distance. Thus, an inner seal (first seal) 58b is provided.
[0036]
The outer seal 58a and the inner seal 58b can be selected in various shapes such as a tapered shape (lip shape), a trapezoidal shape, or a bowl shape. The outer seal 58a contacts the first flat portion 52 provided on the first metal separator 18, while the inner seal 58b directly contacts the solid polymer electrolyte membrane 36 constituting the electrolyte membrane / electrode structure 16. .
[0037]
As shown in FIG. 5, the outer seal 58a includes the oxidant gas inlet communication hole 30a, the cooling medium outlet communication hole 32b, the fuel gas outlet communication hole 34b, the fuel gas inlet communication hole 34a, the cooling medium inlet communication hole 32a, and the oxidant. The gas outlet communication hole 30b is surrounded. The inner seal 58b surrounds the fuel gas flow path 44, and an outer peripheral end portion of the electrolyte membrane / electrode structure 16 is disposed between the inner seal 58b and the outer seal 58a.
[0038]
An outer seal (second seal) 58c corresponding to the outer seal 58a and an inner seal (second seal) 58d corresponding to the inner seal 58b are provided on the surface 20b of the second metal separator 20 (see FIG. 6). . The outer seal 58c and the inner seal 58d have the same shape as the outer seal 58a and the inner seal 58b described above.
[0039]
As shown in FIG. 5, the outer seal 58 a includes an inlet connection portion 60 that connects the oxidant gas inlet communication hole 30 a and the oxidant gas flow path 42, an oxidant gas outlet communication hole 30 b, and the oxidant gas flow path. And an outlet connecting portion 62 that communicates with 42.
[0040]
The inlet connecting portion 60 is configured by a plurality of receiving portions 64 that cut out the outer seal 58a intermittently along the arrow C direction and extend in the arrow B direction. Between each receiving part 64, the communicating path for oxidant gas is formed. Similarly, the outlet connecting portion 62 includes a plurality of receiving portions 66 that partially cut out the outer seal 58a and extend in the arrow B direction. Between each receiving part 66, the communicating path for oxidizing gas is formed.
[0041]
As shown in FIG. 7, the receiving portion 64 of the inlet connecting portion 60 and the seal overlapping portion 68 of the outer seal 58 c overlap each other on both surfaces 20 a and 20 b of the second metal separator 20. The seal overlapping portion 68 refers to a part of the outer seal 58c that overlaps the receiving portion 64 of the outer seal 58a with the second metal separator 20 interposed therebetween. The receiving part 64 extends in a direction intersecting with the seal overlapping part 68 and is configured to be longer than the seal width dimension of the seal overlapping part 68, that is, the seal width dimension of the outer seal 58c. 64 and the seal overlap portion 68 are set to have substantially the same amount of seal deformation in the stacking direction relative to the load in the stacking direction.
[0042]
Specifically, each receiving portion 64 and the seal overlapping portion 68 have substantially the same load per unit length, that is, a seal linear pressure, and the seal length L1 of the receiving portion 64 and the seal overlapping portion 68. The seal length L2 is set to substantially the same length. The seal length L2 is the length of the seal overlapping portion 68 corresponding to the arrangement interval of the receiving portions 64. The receiving portion 64 and the seal overlapping portion 68 do not need to be formed of the same material as long as the spring constants are substantially the same, and various materials can be selected.
[0043]
The outlet connecting portion 62 is configured in the same manner as the inlet connecting portion 60 described above, and the receiving portions 64 that overlap each other on both surfaces 20a and 20b of the second metal separator 20 and the seal overlapping portion 70 of the outer seal 58c are laminated. The amount of seal deformation in the stacking direction is set to be approximately the same with respect to the load in the direction (see FIG. 5).
[0044]
As shown in FIG. 6, on the surface 20b of the second metal separator 20, an inlet connecting portion 72 that connects the cooling medium inlet communication hole 32a and the cooling medium flow path 46, the cooling medium outlet communication hole 32b, and the cooling medium. An outlet connecting portion 74 that communicates with the flow path 46 is provided. The inlet connecting portion 72 includes an outer seal 58c and an inner seal 58d, and is provided intermittently in the direction of arrow C, and includes a plurality of receiving portions 76 extending in the direction of arrow B. Similarly, the outlet connecting portion 74 includes an outer seal 58 c and an inner seal 58 d that are intermittently provided in the direction of the arrow C and includes a plurality of receiving portions 78 extending in the direction of the arrow B.
[0045]
As shown in FIG. 8, the inlet connecting portion 72 overlaps the seal overlapping portions 80 a and 80 b constituting the outer seal 58 a and the inner seal 58 b of the surface 20 a with the second metal separator 20 interposed therebetween. The receiving portions 76 and the seal overlapping portions 80a and 80b constituting the inlet connecting portion 72 are set to have substantially the same amount of seal deformation in the stacking direction with respect to the load in the stacking direction. Specifically, the seal length L3 of the receiving portion 76 is set equal to a value obtained by adding the seal lengths L4 and L5 of the seal overlapping portions 80a and 80b (L3 = L4 + L5). The seal lengths L4 and L5 are the lengths of the seal overlapping portions 80a and 80b corresponding to the arrangement intervals of the receiving portions 76. In addition, although the receiving part 76 is integrally provided over the seal | sticker superposition | polymerization part 80a, 80b, you may divide | segment and comprise for every seal | sticker superposition | polymerization part 80a, 80b.
[0046]
Similarly, each receiving portion 78 constituting the outlet connecting portion 74 overlaps with the seal overlap portions 82a and 82b of the outer seal 58a and the inner seal 58b on both surfaces 20a and 20b of the second metal separator 20, as shown in FIG. ing. The receiving portion 78 and the seal overlapping portions 82a and 82b are set to have substantially the same amount of seal deformation in the stacking direction with respect to the load in the stacking direction.
[0047]
As shown in FIG. 6, on the surface 20b, an inlet connection portion 84 and an outlet connection portion 86 are provided in the vicinity of the fuel gas inlet communication hole 34a and the fuel gas outlet communication hole 34b. The inlet connecting portion 84 is provided with a plurality of receiving portions 88 arranged in the direction of arrow C, while the outlet connecting portion 86 is similarly provided with a plurality of receiving portions 90 arranged in the direction of arrow C.
[0048]
Each receiving portion 88 overlaps with the seal overlapping portions 92a and 92b of the outer seal 58a and the inner seal 58b with the second metal separator 20 in between. Similarly, each receiving portion 90 overlaps the seal overlapping portions 94a and 94b of the outer seal 58a and the inner seal 58b with the second metal separator 20 interposed therebetween.
[0049]
The inlet connecting portion 84 and the seal overlapping portions 92a and 92b, and the outlet connecting portion 86 and the seal overlapping portions 94a and 94b are set to have substantially the same amount of seal deformation in the stacking direction with respect to the load in the stacking direction. , Has the same configuration as the inlet connection portion 72. In the vicinity of the inlet connecting portion 84 and the outlet connecting portion 86, a plurality of supply hole portions 96 and discharge hole portions 98 are respectively formed outside the inner seal 58d. The supply hole 96 and the discharge hole 98 are formed through the surface 20a of the second metal separator 20 inward of the inner seal 58b and on the inlet side and the outlet side of the fuel gas passage 44 (see FIG. 5). .
[0050]
The operation of the fuel cell 10 configured as described above will be described below.
[0051]
First, as shown in FIG. 1, a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 34a, and an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 30a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 32a.
[0052]
For this reason, the oxidant gas is introduced into the oxidant gas flow path 42 of the first metal separator 18 from the oxidant gas inlet communication hole 30a (see FIG. 3), and moves vertically upward while meandering in the arrow B direction. And supplied to the cathode side electrode 40 constituting the electrolyte membrane / electrode structure 16. On the other hand, the fuel gas is introduced into the fuel gas flow path 44 of the second metal separator 20 from the fuel gas inlet communication hole 34a through the supply hole portion 96 (see FIG. 2), and vertically upward while meandering in the direction of arrow B. To the anode side electrode 38 constituting the electrolyte membrane / electrode structure 16.
[0053]
Accordingly, in each electrolyte membrane / electrode structure 16, the oxidant gas supplied to the cathode side electrode 40 and the fuel gas supplied to the anode side electrode 38 are consumed by an electrochemical reaction in the electrode catalyst layer. Power generation is performed.
[0054]
Next, the consumed fuel gas supplied to the anode side electrode 38 passes through the discharge hole portion 98 and is discharged in the direction of arrow A along the fuel gas outlet communication hole 34b. Similarly, the oxidant gas supplied to and consumed by the cathode side electrode 40 is discharged in the direction of arrow A along the oxidant gas outlet communication hole 30b.
[0055]
The cooling medium supplied to the cooling medium inlet communication hole 32a is introduced into the cooling medium flow path 46 between the first and second metal separators 18 and 20, and then flows in the direction of arrow B. The cooling medium is discharged from the cooling medium outlet communication hole 32b after the electrolyte membrane / electrode structure 16 is cooled.
[0056]
In this case, in this embodiment, in order to supply the oxidant gas from the oxidant gas inlet communication hole 30a to the oxidant gas flow path 42, the surface 20a of the second metal separator 20 includes a plurality of receiving portions 64. An inlet connection 60 is provided. As shown in FIG. 5, the inlet connecting portion 60 forms a part of the outer seal 58 a, and the surface 20 b of the second metal separator 20 overlaps with the receiving portion 64 of the inlet connecting portion 60. A seal overlap portion 68 is provided. The seal overlap portion 68 constitutes a part of the outer seal 58c, and the seal overlap portion 68 and the receiving portion 64 have elasticity and are easily deformed.
[0057]
Therefore, as shown in FIG. 7, each receiving portion 64 of the inlet connecting portion 60 and the seal overlapping portion 68 have substantially the same seal linear pressure, and the seal length L1 of the receiving portion 64 and the seal overlapping portion 68. The seal length L2 is set to substantially the same length. For this reason, the receiving portions 64 and the seal overlapping portions 68 that overlap each other on both surfaces 20a and 20b of the second metal separator 20 are maintained substantially the same in the stacking direction in the stacking direction with respect to the stacking direction load.
[0058]
Specifically, when the seal length L1 of the receiving portion 64 and the seal length L2 of the seal overlapping portion 68 are changed as shown in FIG. 9, the seal length L1 and the seal are changed with respect to the load in the stacking direction. The difference in compression height between the receiving portion 64 and the seal overlapping portion 68 with respect to the ratio (L1 / L2) to the length L2 varied as shown in FIG. Therefore, when the ratio of the seal length L1 to the seal length L2 is approximately 1.0, that is, the relationship of the seal length L1 = the seal length L2 is satisfied, there is no difference in the compression height.
[0059]
Thereby, in the second metal separator 20, the amount of seal deformation on both surfaces 20a and 20b becomes substantially the same, and the balance of the seal linear pressure (load) with respect to the second metal separator 20 does not become uneven. It becomes possible to satisfactorily prevent the deformation of the second metal separator 20 itself. In addition, the oxidant gas can be smoothly and reliably supplied from the oxidant gas inlet communication hole 30a to the oxidant gas flow path 42 without causing deformation in the inlet connection part 60.
[0060]
On the other hand, in the outlet connecting portion 62, the amount of seal deformation between each receiving portion 66 and the seal overlapping portion 70 is substantially the same as in the above-described inlet connecting portion 60. This prevents deformation of the second metal separator 20 itself and reliably discharges exhaust gas (used oxidant gas) from the oxidant gas flow path 42 to the oxidant gas outlet communication hole 30b.
[0061]
Further, as shown in FIG. 6, an inlet connection portion 72 that connects the cooling medium inlet communication hole 32 a and the cooling medium flow path 46 is provided on the surface 20 b of the second metal separator 20. Each receiving portion 76 of the inlet connecting portion 72 and the seal overlapping portions 80a and 80b that overlap each other with the second metal separator 20 interposed between the receiving portion 76 and the seal deformation in the stacking direction with respect to the load in the stacking direction. The amount is set to be approximately the same. That is, as shown in FIG. 8, the seal length L3 of the receiving portion 76 is equal to the added value of the seal lengths L4 and L5 of the seal overlapping portions 80a and 80b (L3 = L4 + L5).
[0062]
As a result, the amount of seal deformation between the inlet connecting portion 72 and the seal overlapping portions 80a and 80b becomes substantially the same, preventing the second metal separator 20 itself from being deformed, and from the cooling medium inlet communication hole 32a to the cooling medium flow path 46. The cooling medium can be supplied smoothly and reliably.
[0063]
On the other hand, in the outlet connecting portion 74 as well, the amount of seal deformation between the receiving portions 78 and the seal overlapping portions 82a and 82b is substantially the same, and the cooling medium can be smoothly discharged into the cooling medium outlet communication hole 32b. It becomes possible.
[0064]
Furthermore, as shown in FIG. 6, an inlet connecting portion 84 and an outlet connecting portion 86 that communicate the fuel gas inlet communication hole 34 a and the fuel gas outlet communication hole 34 b with the fuel gas flow path 44 are provided. The receiving portions 88, 90 and the seal overlapping portions 92a, 92b and 94a, 94b are set to have substantially the same amount of seal deformation, so that the fuel gas can be smoothly supplied and discharged, and the second metal separator 20 The prevention of the deformation of itself is performed well.
[0065]
Thereby, in this embodiment, while stabilizing the power generation performance of the fuel cell 10, the flow rates of the fuel gas, the oxidant gas, and the cooling medium are uniformized with a simple configuration, and the power generation performance for each power generation cell 12 is achieved. It is possible to obtain an effect that the homogenization and stabilization are reliably achieved.
[0066]
【The invention's effect】
In the fuel cell according to the present invention, the second seal is provided between the cooling medium flow path and the cooling medium communication hole. Provided intermittently , And overlap with the seal overlap part of the first seal across the separator plural The amount of deformation of the receiving portion and the seal overlapping portion overlapping the receiving portion is set to be substantially the same with respect to the load in the stacking direction.
[0067]
On the other hand, the first seal is between the reaction gas flow path and the reaction gas communication hole. Provided intermittently , And overlap with the seal overlap part of the second seal across the separator plural The amount of deformation of the receiving portion and the seal overlapping portion overlapping the receiving portion is set to be substantially the same with respect to the load in the stacking direction.
[0068]
For this reason, the deformation amounts of the first seal and the second seal are substantially the same on both surfaces of the separator, and the load balance in the power generation cell plane and the load balance for each power generation cell are made uniform. Therefore, the power generation performance can be stabilized, the flow rates of the reaction gas and the cooling medium can be made uniform, and the power generation performance for each power generation cell can be made uniform and stable.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of a main part of a power generation cell constituting a fuel cell according to an embodiment of the present invention.
FIG. 2 is a cross-sectional explanatory view of a main part of the fuel cell.
FIG. 3 is an explanatory cross-sectional view of a main part of another part of the fuel cell.
FIG. 4 is a front explanatory view of a first metal separator constituting the power generation cell.
FIG. 5 is a front explanatory view of one surface of a second metal separator constituting the power generation cell.
FIG. 6 is a front explanatory view of the other surface of the second metal separator constituting the power generation cell.
FIG. 7 is an explanatory diagram of an oxidant gas inlet connection provided in the power generation cell.
FIG. 8 is an explanatory diagram of an inlet connection portion of a cooling medium provided in the power generation cell.
FIG. 9 is a diagram showing the relationship between the seal length and the length of the receiving portion.
FIG. 10 is an explanatory diagram of a difference in compression height depending on a ratio between a seal length and a length of a receiving portion.
11 is an explanatory diagram of a seal structure disclosed in Patent Document 1. FIG.
FIG. 12 is a partial explanatory diagram of a conventional separator.
[Explanation of symbols]
10 ... Fuel cell 12 ... Power generation cell
16 ... Electrolyte membrane / electrode structure 18, 20 ... Metal separator
30a ... Oxidant gas inlet communication hole 30b ... Oxidant gas outlet communication hole
32a ... Cooling medium inlet communication hole 32b ... Cooling medium outlet communication hole
34a ... Fuel gas inlet communication hole 34b ... Fuel gas outlet communication hole
36 ... Solid polymer electrolyte membrane 38 ... Anode side electrode
40 ... Cathode side electrode 42 ... Oxidant gas flow path
44 ... Fuel gas flow path 46 ... Cooling medium flow path
50, 56: Sealing member 52, 54: Plane portion
58a, 58c ... outer seal 58b, 58d ... inner seal
60, 72, 84 ... Inlet connection 62, 74, 86 ... Outlet connection
64, 66, 76, 78, 88, 90 ... receiving part
68, 70, 80a, 80b, 82a, 82b, 92a, 92b, 94a, 94b...
96 ... Supply hole 98 ... Discharge hole

Claims

A plurality of power generation cells in which an electrolyte / electrode structure and a separator, each having an electrolyte disposed between a pair of electrodes, are stacked, and a reaction gas is passed along the electrode surface between the electrolyte / electrode structure and the separator. A reaction gas flow path to be supplied is formed, a cooling medium flow path for supplying a cooling medium is formed between the separators of the power generation cells adjacent to each other, and the power generation cell penetrates in the stacking direction. An internal manifold type fuel cell provided with a reaction gas communication hole communicating with the reaction gas flow channel and a cooling medium communication hole communicating with the cooling medium flow channel,
A first seal that seals the reaction gas flow path is provided on one surface of the separator, and a second seal that seals the cooling medium flow path is provided on the other surface of the separator,
The second seal is provided intermittently at a connecting portion between the cooling medium flow path and the cooling medium communication hole, and includes a plurality of receiving portions that overlap the first seal with the separator interposed therebetween, receiving the said overlap receiving portion first seal sealing overlapping portions, respectively, while being set in the seal width and substantially the same spring constant substantially the same, the sum of the lengths of the plurality of receiving the By setting the length of the seal overlap portion of the first seal located at a position corresponding to the connecting portion with the separator interposed therebetween, the deformation amount in the stacking direction is substantially reduced with respect to the load in the stacking direction. A fuel cell characterized by being set identically.

A plurality of power generation cells in which an electrolyte / electrode structure and a separator, each having an electrolyte disposed between a pair of electrodes, are stacked, and a reaction gas is passed along the electrode surface between the electrolyte / electrode structure and the separator. A reaction gas flow path to be supplied is formed, a cooling medium flow path for supplying a cooling medium is formed between the separators of the power generation cells adjacent to each other, and the power generation cell penetrates in the stacking direction. An internal manifold type fuel cell provided with a reaction gas communication hole communicating with the reaction gas flow channel and a cooling medium communication hole communicating with the cooling medium flow channel,
A first seal that seals the reaction gas flow path is provided on one surface of the separator, and a second seal that seals the cooling medium flow path is provided on the other surface of the separator,
The first seal is provided intermittently at a connection portion between the reaction gas flow path and the reaction gas communication hole, and includes a plurality of receiving portions that overlap the second seal with the separator interposed therebetween, receiving the said overlap receiving portion second seal sealing overlapping portions, respectively, while being set to the seal width, and approximately the same spring constant substantially the same, the sum of the lengths of the plurality of receiving the By setting the length of the seal overlapping portion of the second seal located at a position corresponding to the connecting portion across the separator, the deformation amount in the stacking direction is substantially equal to the load in the stacking direction. A fuel cell characterized by being set identically.

3. The fuel cell according to claim 1, wherein the electrolyte / electrode structure includes an electrolyte membrane sandwiched between the first and second electrodes, and the first electrode has a smaller surface area than the second electrode. Is set,
The first seal is provided on the separator on the first electrode side,
An inner seal disposed between the electrolyte membrane and the separator;
An outer seal disposed between adjacent separators;
A fuel cell comprising:

4. The fuel cell according to claim 3, wherein the second seal is an inner seal corresponding to the inner seal of the first seal;
An outer seal corresponding to the outer seal of the first seal;
A fuel cell comprising:

5. The fuel cell according to claim 1, wherein the receiving portion and the seal overlapping portion are set to substantially the same seal linear pressure. 6.

6. The fuel cell according to claim 1, wherein the receiving portion has a seal length extending in a direction intersecting the seal overlapping portion longer than a seal width dimension of the seal overlapping portion. A fuel cell comprising a scale.