JP4295847B2 - Polymer electrolyte fuel cell system - Google Patents

Polymer electrolyte fuel cell system Download PDF

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JP4295847B2
JP4295847B2 JP33623298A JP33623298A JP4295847B2 JP 4295847 B2 JP4295847 B2 JP 4295847B2 JP 33623298 A JP33623298 A JP 33623298A JP 33623298 A JP33623298 A JP 33623298A JP 4295847 B2 JP4295847 B2 JP 4295847B2
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JP2000164231A (en
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宗一郎 霜鳥
和夫 齊藤
美知郎 堀
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Toshiba Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
    • H01M8/04089—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants
    • H01M8/04119—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants with simultaneous supply or evacuation of electrolyte; Humidifying or dehumidifying
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

Description

【０００１】
【発明の属する技術分野】
本発明は、固体高分子型燃料電池システムに係り、特に、温湿度交換手段における加湿量を適切に制御すべく改良を施した固体高分子型燃料電池システムに関するものである。
【０００２】
【従来の技術】
燃料電池は、水素等の燃料と空気等の酸化剤を電気化学的に反応させることにより、燃料の持つ化学エネルギーを直接電気エネルギーに変換する装置である。この燃料電池は、用いられる電解質の種類により、アルカリ型、固体高分子型、リン酸型等の低温作動燃料電池と、溶融炭酸塩型、固体酸化物型等の高温作動燃料電池とに大別される。
なかでも、電解質としてプロトン伝導性を有する固体高分子電解質膜を用いた固体高分子型燃料電池（以下、ＰＥＦＣと記す）は、コンパクトな構造で高出力密度が得られ、かつ簡易なシステムで運転が可能なことから、宇宙用や車両用などの電源として注目されている。
【０００３】
一般的な燃料電池システムは、メタン等の炭化水素またはメタノール等のアルコールを燃料とし、燃料を改質して水素リッチガスを生成する改質器、水素リッチガス中のＣＯを低減するシフト反応器および選択酸化器、酸化剤として空気を供給するコンプレッサー、電池反応による発熱を取り除く冷却系、そして燃料電池本体から構成されている。そして、燃料電池本体では、燃料ガスに含まれる水素から水素イオンが生成され、この水素イオンが電解質膜内を伝導して酸化剤ガスに含まれる酸素と反応して水を生じる。その際に、水素の化学エネルギーの一部が直接電気エネルギーとして取り出される。
【０００４】
また、電解質膜は含水状態で良好な水素イオン伝導性を示すため、運転中は、電解質膜に水分を与えて含水状態に保つ加湿が不可欠である。この加湿方法としては、反応ガスに予め水蒸気を添加する外部加湿方式、電池冷却水と未反応ガスを加湿膜を介して接触させ、電池冷却水の一部を未反応ガスに添加する間接内部加湿方式、電池冷却水を電池反応部の反応ガスに直接供給する直接内部加湿方式などが知られている。
【０００５】
一方、近年、電池部を通過した既反応ガスと電池部を通過する前の未反応ガスを水蒸気透過膜を介して接触させ、水蒸気の分圧差により、既反応ガスに含まれる水分を未反応ガスに添加する加湿方式が提案されている(J. F. McElroy and L. J. Nuttall, "Status of Solid Polymer Electrolyte Technology and Potential for Transportation Applications", 17th IECEC, 1982, pp.667-671.)。
この場合、電極反応に伴い水蒸気が生成されるため、既反応ガスには飽和もしくはそれに近い水蒸気が含まれることになる。一方、未反応ガスには含まれる水蒸気が少ないため、それぞれのガスには水蒸気分圧差が生じ、これを駆動力として、水蒸気を濃度拡散させることができる。この方法は、上記の文献でも述べられているように、相変化を生じさせないというところに特徴がある。なお、特開平６−１３２０３８号にも同様の加湿方法が開示されている。
【０００６】
図２４は、従来から用いられている一般的な固体高分子型燃料電池システムの構成を示した図である。すなわち、固体高分子型燃料電池本体は、燃料極１、酸化剤極２からなる一対のガス拡散電極に、イオン伝導性とガス分離機能を有する固体高分子電解質膜３を挟持させて構成されている。そして、燃料極１に水素等の燃料ガス、酸化剤極２に空気等の酸化剤ガスを供給すると、電気化学反応により起電力が生じる。この電気化学反応は発熱反応であるため、燃料電池本体には、余剰な熱を除去するために、内部に冷却水を流通させた冷却水板４が配設されている。
【０００７】
また、燃料を改質して水素リッチガスを生成する燃料改質器５、水素リッチガス中のＣＯを低減するＣＯ低減器６が設けられ、改質された燃料ガスが燃料極１に供給されるように構成されている。この燃料ガスは、電池反応によって所定量消費された後、燃料排ガスとして改質器５のバーナーに供給され、改質器の熱源となる。
【０００８】
一方、燃料電池の冷却水板４には、冷却水ポンプ７により不凍液が供給されるように構成されている。冷却水板４に供給された不凍液は、電池反応によって生じた熱を取り除いた後、ファン８により冷却され、循環される。また、ファン８の入口には、不凍液リザーバタンク９が接続され、不凍液の量を調整するように構成されている。
【０００９】
また、コンプレッサー１０によって供給された空気は、温湿度交換手段１１の未反応ガス流路１２を経て燃料電池の酸化剤極２に供給されるように構成されている。この酸化剤ガスは、電池反応により所定量消費された後、電池反応によって生じた生成水を回収して電池外に排出される。排出された空気は、温湿度交換手段１１の既反応ガス流路１３に供給され、保水性多孔質体１４を介して、水分を未反応空気に与え、未反応空気を加湿した後、酸化剤排ガスとして系外に排出されるように構成されている。
【００１０】
【発明が解決しようとする課題】
しかしながら、上述したような従来の加湿方法には、以下に述べるような様々な問題点がある。
すなわち、水蒸気透過膜を介して既反応ガスの水蒸気を未反応ガスに添加して加湿する方法では、お互いのガスの水蒸気分圧差だけで加湿を行うため、既反応ガス側での水蒸気濃度勾配による拡散抵抗、水蒸気透過膜内の拡散抵抗、さらに未反応ガス側での拡散抵抗など、水蒸気の拡散抵抗が非常に大きくなるため、十分な加湿をする場合には大きな加湿器が必要となるといった問題がある。
【００１１】
また、この方法では、加湿量は、既反応ガスに含まれる水蒸気の量と媒体となる多孔質体の交換面積により決まるが、通常、多孔質体の交換面積は一定なので、加湿量は既反応ガスに含まれる水蒸気の量、すなわち水蒸気分圧により決まることになる。
水蒸気分圧は温度や出力などの作動条件により異なるが、どのような作動条件であっても、必要な加湿量が得られるように制御する必要がある。必要な加湿量が得られない場合には、電解質膜中の水分が減少し、水素イオン伝導率が低下して性能が低下してしまうからである。さらに、反応部を通過した既反応ガス中の水分も減少し、水蒸気分圧が下がるので、ますます加湿量が低下するという悪循環に陥る可能性がある。
【００１２】
このように、水蒸気透過膜を介して既反応ガスの水蒸気を未反応ガスに添加して加湿する方法では、加湿量が既反応ガス中の水蒸気分圧により決まるため、加湿量が少ないなどバランスした状態を外れると、加湿量の制御が難しいという問題点がある。
【００１３】
本発明は、上述したような従来技術の問題点を解消するために提案されたものであり、その目的は、温湿度交換手段における加湿量を適切に制御することができる、高性能の固体高分子型燃料電池システムを提供することにある。
【００１４】
【課題を解決するための手段】
上記の目的を達成するため、請求項１に記載の発明は、固体高分子膜を電解質とする固体高分子型燃料電池スタックと、前記燃料電池スタックの反応部を通過した既反応ガスと前記反応部を通過する前の未反応ガスとの熱と水分の交換を行う温湿度交換手段とを有する固体高分子型燃料電池システムにおいて、前記温湿度交換手段の既反応ガス流路の入口側と出口側を結ぶバイパス通路を形成し、前記バイパス通路への切替弁を設け、前記反応部を通過した既反応ガスの温度または湿度を検出する第１の検出手段と、前記反応部を通過する前の未反応ガスの温度または湿度を検出する第２の検出手段とを備え、前記各検出手段によって検出される前記未反応ガス温度と前記既反応ガス温度との比例関係を示す温湿度交換手段のバランス曲線と、生成水が効率良く排出されるために既反応ガス中の水蒸気量が未反応ガス中の水蒸気量と生成水と燃料ガス入口及び出口の水蒸気量の差分との和と等しくなるための前記既反応ガス温度及び前記未反応ガス温度の関係を示す電池水バランス曲線とに基づいて、前記既反応ガス温度が前記電池水バランス曲線上の既反応ガス温度を下回った場合に前記切替弁を制御して前記バイパス通路へ前記既反応ガスを流し、その後、前記既反応ガス温度が前記電池水バランス曲線上の既反応ガス温度以上となった場合に前記切替弁を制御して前記バイパス通路を閉じ前記既反応ガス通路へ前記既反応ガスを流すことを特徴とする。上記のような構成を有する請求項１に記載の発明によれば、既反応ガス流路の入口側と出口側を結ぶバイパス通路への切替弁を制御することにより、温湿度交換手段に供給される既反応ガスの流量を調整することができるので、未反応ガスの加湿量を容易に制御することが可能となる。
【００１５】
請求項２に記載の発明は、固体高分子膜を電解質とする固体高分子型燃料電池スタックと、前記燃料電池スタックの反応部を通過した既反応ガスと前記反応部を通過する前の未反応ガスとの熱と水分の交換を行う温湿度交換手段を有する固体高分子型燃料電池システムにおいて、前記温湿度交換手段の未反応ガス流路の入口側と出口側を結ぶバイパス通路を形成し、前記バイパス通路への切替弁を設け、前記反応部を通過した既反応ガスの温度または湿度を検出する第１の検出手段と、前記反応部を通過する前の未反応ガスの温度または湿度を検出する第２の検出手段とを備え、前記各検出手段によって検出される前記未反応ガス温度と前記既反応ガス温度との比例関係を示す温湿度交換手段のバランス曲線と、生成水が効率良く排出されるために既反応ガス中の水蒸気量が未反応ガス中の水蒸気量と生成水と燃料ガス入口及び出口の水蒸気量の差分との和と等しくなるための前記既反応ガス温度及び前記未反応ガス温度の関係を示す電池水バランス曲線とに基づいて、前記既反応ガス温度が前記電池水バランス曲線上の既反応ガス温度を下回った場合に前記切替弁を制御して前記バイパス通路へ前記未反応ガスを流し、その後、前記既反応ガス温度が前記電池水バランス曲線上の既反応ガス温度以上となった場合に前記切替弁を制御して前記バイパス通路を閉じ前記未反応ガス通路へ前記未反応反応ガスを流すことを特徴とする。上記のような構成を有する請求項２に記載の発明によれば、未反応ガス流路の入口側と出口側を結ぶバイパス通路への切替弁を制御することにより、温湿度交換手段に供給される未反応ガスの流量を調整することができるので、未反応ガスの加湿量を容易に制御することが可能となる。
【００１６】
以上のような請求項１又は請求項２に記載の発明によれば、既反応ガス流路に対するバイパス通路への切替弁、あるいは、未反応ガス流路に対するバイパス通路への切替弁を制御することができるので、温湿度交換手段における加湿量をより精度良く制御することが可能となる。
【００１７】
請求項３に記載の発明は、請求項１に記載の固体高分子型燃料電池システムにおいて、前記温湿度交換手段が、複数の交換セルから構成され、前記複数の交換セルのうち、一部の交換セルに流通する第１の既反応ガス流路と、残りの交換セルに流通する第２の既反応ガス流路とが設けられ、前記第２の既反応ガス流路を開閉する開閉弁が設けられ、前記温湿度交換手段のバランス曲線と、前記電池水バランス曲線とに基づいて、前記既反応ガス温度が前記電池水バランス曲線上の既反応ガス温度を上回った場合に前記開閉弁を開いて前記第２の既反応ガス流路へ前記既反応ガスを流し、その後、前記既反応ガス温度が前記電池水バランス曲線上の既反応ガス温度以下となった場合に前記開閉弁を閉じて前記第１の既反応ガス流路のみへ前記既反応ガスを流すことを特徴とする。上記のような構成を有する請求項３に記載の発明によれば、温湿度交換手段が複数の交換セルから構成されている場合に、第１の既反応ガス流路と第２の既反応ガス流路を設け、第２の既反応ガス流路を開閉する開閉弁を制御することにより、温湿度交換手段に供給される既反応ガスの流量を調整することができるので、未反応ガスの加湿量を容易に制御することが可能となる。
【００１８】
請求項４に記載の発明は、請求項２に記載の固体高分子型燃料電池システムにおいて、前記温湿度交換手段が、複数の交換セルから構成され、前記複数の交換セルのうち、一部の交換セルに流通する第１の未反応ガス流路と、残りの交換セルに流通する第２の未反応ガス流路とが設けられ、前記第２の未反応ガス流路を開閉する開閉弁が設けられ、前記温湿度交換手段のバランス曲線と、前記電池水バランス曲線とに基づいて、前記既反応ガス温度が前記電池水バランス曲線上の既反応ガス温度を上回った場合に前記開閉弁を開いて前記第２の未反応ガス流路へ前記未反応ガスを流し、その後、前記既反応ガス温度が前記電池水バランス曲線上の既反応ガス温度以下となった場合に前記開閉弁を閉じて前記第１の未反応ガス流路のみへ前記未反応ガスを流すことを特徴とする。上記のような構成を有する請求項４に記載の発明によれば、温湿度交換手段が複数の交換セルから構成されている場合に、第１の未反応ガス流路と第２の未反応ガス流路を設け、第２の未反応ガス流路を開閉する開閉弁を制御することにより、温湿度交換手段に供給される未反応ガスの流量を調整することができるので、未反応ガスの加湿量を容易に制御することが可能となる。
【００２１】
【発明の実施の形態】
以下、本発明の実施の形態（以下、実施形態という）について、図面を参照して具体的に説明する。なお、図２４に示した従来型と同一の部材には同一の符号を付して、説明は省略する。
【００２２】
［１．第１実施形態］
［１−１．構成］
図１は、本発明に係る固体高分子型燃料電池システムの第１実施形態の構成を示す図である。すなわち、本実施形態においては、温湿度交換手段１１の既反応ガス流路１３の入口と出口を結ぶバイパス通路２０が設けられ、燃料電池の酸化剤極２から温湿度交換手段１１の既反応ガス流路１３へ至るライン上に、前記バイパス通路２０へ切り替える切替弁２１と、既反応ガス温度センサ２２が設けられている。また、温湿度交換手段１１の未反応ガス流路１２から燃料電池の酸化剤極２へ至るライン上に、未反応ガス温度センサ２３が設けられている。また、前記既反応ガス温度センサ２２と未反応ガス温度センサ２３の検出結果に基づいて、前記切替弁２１の切り替え動作を制御するコントロールユニット２４が設けられている。
【００２３】
図２は、前記切替弁２１の切り替え動作を制御するための未反応ガス温度と既反応ガス温度の関係を示す図である。すなわち、温湿度交換手段１１では、未反応ガス温度Ｔｄ、すなわち未反応ガス出口露点と、既反応ガス温度Ｔｗ、すなわち既反応ガス入口露点は、比例関係にある（Ｔｗ＝Ｂ（Ｔｄ））。
一方、燃料電池本体では、反応による生成水が反応ガス中に蒸発し、燃料ガスの入口／出口の水蒸気の差分とともに排出空気に含まれる。生成水が効率良く排出されるためには、既反応ガス温度Ｔｗと未反応ガス温度Ｔｄは、既反応ガス中の水蒸気量が、未反応ガス中の水蒸気量と、生成水と、燃料ガス入口／出口の水蒸気量の差分との和と等しくなる関係、すなわち１対１の関係である必要がある（Ｔｗ＝Ａ（Ｔｄ））。
【００２４】
図２に示したように、この２つの曲線が重なる点Ａでは、温湿度交換手段１１で加湿された未反応ガスの温度Ｔｄにおいて含まれる水蒸気量と、生成水と、燃料ガス入口／出口の水蒸気量の差分との和が、温湿度交換手段１１に供給される既反応ガスの温度Ｔｗにおいて含まれる水蒸気量と等しくなり、生成水を効率良く排出できて、定常な運転が可能となる。
【００２５】
［１−２．作用］
上記のような構成を有する本実施形態の作用を、図３に示したフローチャートにしたがって説明する。
図３に示したように、制御開始時には、切替弁２１は既反応ガス流路側へ開かれており、温湿度交換手段１１によって既反応ガスから未反応ガスへ加湿が行われる。
【００２６】
そして、ステップ３０１において、前記コントロールユニット２４によって、既反応ガス温度センサ２２及び未反応ガス温度センサ２３の検出結果が監視され、Ｔｗ＜Ａ（Ｔｄ）−ΔＴｗの条件を満足しない場合、すなわち、既反応ガス温度が所定の値以上である場合には、そのまま運転が行われる。
一方、既反応ガス温度がＴｗ＜Ａ（Ｔｄ）−ΔＴｗの条件を満足した場合、すなわち、図２のＢ点のように、既反応ガス温度が、燃料電池本体のバランス曲線Ｔｗ＝Ａ（Ｔｄ）より下の領域に推移すると、ステップ３０２に進み、バイパス通路２０へ切り替わる。なお、この場合、図２に示すように、バランス曲線に対して所定の幅ΔＴｗを設定し、この幅より下回るときにバイパス通路へ切り替わるようにすると、切り替えの回数を少なくできる。
【００２７】
このようにして、バイパス通路２０へ切り替わると、既反応ガスが温湿度交換手段１１に供給されなくなるため、未反応ガスへの加湿が行われなくなり、図２のＢ点→Ｃ点のように、未反応ガス温度が低下していく。
そして、ステップ３０３において、前記コントロールユニット２４によって、既反応ガス温度センサ２２及び未反応ガス温度センサ２３の検出結果が監視され、Ｔｗ≧Ａ（Ｔｄ）＋ΔＴｗの条件を満足しない場合、すなわち、既反応ガス温度が所定の値以下である場合には、そのまま運転が行われる。
【００２８】
そして、未反応ガス温度がさらに低下し、図２のＤ点のように、既反応ガス温度が、燃料電池本体のバランス曲線Ｔｗ＝Ａ（Ｔｄ）よりも上の領域に推移すると、ステップ３０４に進み、再び既反応ガス通路へ切り替えられる。その結果、既反応ガスが温湿度供給手段１１に供給されて、未反応ガスを加湿し、図２のＤ点→Ｃ点のように、未反応ガス温度が上昇する。なお、ここでも、バランス曲線に対して所定の制御幅ΔＴｗを設置している。
以上の制御フローを繰り返すことにより、温湿度交換手段のバランス曲線を外れても、燃料電池本体のバランス曲線上のＣ点に保つ制御を行うことができる。
【００２９】
また、本実施形態の燃料電池システムと、従来のバイパス通路をもたない燃料電池システムを用意し、冷却水により燃料電池本体の温度を変化させて発電試験を行ったところ、以下のような結果が得られた。
まず、未反応ガス温度が６５℃、既反応ガス温度が７０℃となるように発電試験を行ったところ、燃料電池本体の水バランスと、温湿度交換手段のバランスが一致し、２つのシステムとも安定した運転が可能であった（図２のＡ点に相当する）。
【００３０】
次に、既反応ガス温度が６５℃となるように燃料電池本体の温度を下げて試験を行ったところ、従来の燃料電池システムでは、未反応ガス温度が６０℃となるように温湿度交換手段がバランスした。ところが、この条件では、未反応ガス温度に対して既反応ガス温度が低く、燃料電池本体で生成水を十分に排出できず、電極内に水が蓄積してガスの拡散を阻害し、運転を行うことができなかった（図２のＢ点に相当する）。
一方、本実施形態の燃料電池システムでは、切替弁を制御することにより、燃料電池本体で水がバランスする点、すなわち既反応ガス温度が６５℃、未反応ガス温度が５０℃で運転を行うことができ、継続して運転が可能となった（図２のＣ点に相当する）。
【００３１】
［１−３．効果］
このように、本実施形態によれば、温湿度交換手段の既反応ガス流路の入口と出口を結ぶバイパス通路と、このバイパス通路へ切り替える切替弁と、未反応ガス温度センサ及び既反応ガス温度センサを設け、既反応ガス温度センサと未反応ガス温度センサの検出結果に基づいて、切替弁の切り替え動作を制御することによって、燃料電池本体での水がバランスする条件での運転が可能となる。
【００３２】
なお、本実施形態では、検出手段として温度センサを用いたが、湿度センサや露点計で代用しても同様の効果が得られる。また、バイパス流路への切り替えを切替弁を用いて行ったが、バイパス流路と既反応ガス流路の一方もしくは両方に開閉弁を設けても同様の効果が得られる。
【００３３】
［２．第２実施形態］
［２−１．構成］
図４は、本発明に係る固体高分子型燃料電池システムの第２実施形態の構成を示す図である。すなわち、本実施形態においては、温湿度交換手段１１の未反応ガス流路１２の入口と出口を結ぶバイパス通路３０が設けられ、コンプレッサ１０から温湿度交換手段１１の未反応ガス流路１２へ至るライン上に、前記バイパス通路３０へ切り替える切替弁３１が設けられている。また、第１実施形態と同様に、燃料電池の酸化剤極２から温湿度交換手段１１の既反応ガス流路１３へ至るライン上に、既反応ガス温度センサ３２が設けられ、また、温湿度交換手段１１の未反応ガス流路１２から燃料電池の酸化剤極２へ至るライン上に、未反応ガス温度センサ３３が設けられている。さらに、前記既反応ガス温度センサ３２と未反応ガス温度センサ３３の検出結果に基づいて、前記切替弁３１の切り替え動作を制御するコントロールユニット３４が設けられている。
【００３４】
［２−２．作用］
上記のような構成を有する本実施形態の作用を、図５に示したフローチャートにしたがって説明する。
図５に示したように、制御開始時には、切替弁３１は未反応ガス流路側へ開かれており、温湿度交換手段１１によって既反応ガスから未反応ガスへ加湿が行われる。
【００３５】
そして、ステップ５０１において、前記コントロールユニット３４によって、既反応ガス温度センサ３２及び未反応ガス温度センサ３３の検出結果が監視され、Ｔｗ＜Ａ（Ｔｄ）−ΔＴｗの条件を満足しない場合、すなわち、既反応ガス温度が所定の値以上である場合には、そのまま運転が行われる。
一方、既反応ガス温度がＴｗ＜Ａ（Ｔｄ）−ΔＴｗの条件を満足した場合、すなわち、図２のＢ点のように、既反応ガス温度が、燃料電池本体のバランス曲線Ｔｗ＝Ａ（Ｔｄ）より下の領域に推移すると、ステップ５０２に進み、バイパス通路３０へ切り替わる。なお、この場合も、図２に示すように、バランス曲線に対して所定の幅ΔＴｗを設定し、この幅より下回るときにバイパス通路へ切り替わるようにすると、切り替えの回数を少なくできる。
【００３６】
このようにして、バイパス通路３０へ切り替わると、未反応ガスが温湿度交換手段１１に供給されなくなるため、未反応ガスへの加湿が行われなくなり、図２のＢ点→Ｃ点のように、未反応ガス温度が低下していく。
そして、ステップ５０３において、前記コントロールユニット３４によって、既反応ガス温度センサ３２及び未反応ガス温度センサ３３の検出結果が監視され、Ｔｗ≧Ａ（Ｔｄ）＋ΔＴｗの条件を満足しない場合、すなわち、既反応ガス温度が所定の値以下である場合には、そのまま運転が行われる。
【００３７】
そして、未反応ガス温度がさらに低下し、図２のＤ点のように、既反応ガス温度が、燃料電池本体のバランス曲線Ｔｗ＝Ａ（Ｔｄ）よりも上の領域に推移すると、ステップ５０４に進み、再び未反応ガス通路へ切り替えられる。その結果、未反応ガスが温湿度供給手段１１に供給されて、加湿され、図２のＤ点→Ｃ点のように、未反応ガス温度が上昇する。なお、ここでも、バランス曲線に対して所定の制御幅ΔＴｗを設置している。
以上の制御フローを繰り返すことにより、温湿度交換手段のバランス曲線を外れても、燃料電池本体のバランス曲線上のＣ点に保つ制御を行うことができる。
【００３８】
また、第１実施形態と同様に、本実施形態の燃料電池システムと、従来のバイパス通路をもたない燃料電池システムを用意し、冷却水により燃料電池本体の温度を変化させて発電試験を行ったところ、以下のような結果が得られた。
まず、未反応ガス温度が６５℃、既反応ガス温度が７０℃となるように発電試験を行ったところ、燃料電池本体の水バランスと、温湿度交換手段のバランスが一致し、２つのシステムとも安定した運転が可能であった。
【００３９】
次に、既反応ガス温度が６５℃となるように燃料電池本体の温度を下げて試験を行ったところ、本実施形態の燃料電池システムでは、切替弁を制御することにより、燃料電池本体で水がバランスする点、すなわち既反応ガス温度が６５℃、未反応ガス温度が５０℃で運転を行うことができ、継続して運転が可能となった。
【００４０】
［２−３．効果］
このように、本実施形態によれば、温湿度交換手段の未反応ガス流路の入口と出口を結ぶバイパス通路と、このバイパス通路へ切り替える切替弁と、未反応ガス温度センサ及び既反応ガス温度センサを設け、既反応ガス温度センサと未反応ガス温度センサの検出結果に基づいて、切替弁の切り替え動作を制御することによって、燃料電池本体での水がバランスする条件での運転が可能となる。
【００４１】
なお、本実施形態では、検出手段として温度センサを用いたが、湿度センサや露点計で代用しても同様の効果が得られる。また、バイパス流路への切替を切替弁を用いて行ったが、バイパス流路と既反応ガス流路の一方もしくは両方に開閉弁を設けても同様の効果が得られる。
【００４２】
［３．第３実施形態］
［３−１．構成］
図６は、本発明に係る固体高分子型燃料電池システムの第３実施形態の構成を示す図である。すなわち、本実施形態においては、温湿度交換手段１１が複数の交換セルから構成され、これら複数の交換セルのうち、一部の交換セルに流通する第１の既反応ガス流路１３ａと、残りの交換セルに流通する第２の既反応ガス流路１３ｂが設けられ、さらに、前記第２の既反応ガス流路１３ｂを開閉する開閉弁４５が設けられている。
また、温湿度交換手段１１の既反応ガス流路の入口と出口を結ぶバイパス通路４０が設けられ、燃料電池の酸化剤極２から温湿度交換手段１１の既反応ガス流路１３へ至るライン上に、前記バイパス通路４０へ切り替える切替弁４１と、既反応ガス温度センサ４２が設けられている。また、温湿度交換手段１１の未反応ガス流路１２から燃料電池の酸化剤極２へ至るライン上に、未反応ガス温度センサ４３が設けられている。また、前記既反応ガス温度センサ４２と未反応ガス温度センサ４３の検出結果に基づいて、前記切替弁４１及び開閉弁４５の動作を制御するコントロールユニット４４が設けられている。
【００４３】
図７は、本実施形態の温湿度交換手段のセル積層方向の断面図を示したものである。すなわち、温湿度交換手段１１は複数の交換セルで構成され、各交換セルは、未反応ガス流路１２、保水性多孔質体１４及び第１の既反応ガス流路１３ａ、あるいは、未反応ガス流路１２、保水性多孔質体１４及び第２の既反応ガス流路１３ｂから構成されている。
【００４４】
また、図８は第１の既反応ガス流路１３ａ、図９は第２の既反応ガス流路１３ｂ、図１０は未反応ガス流路１２を示したものである。図に示したように、それぞれの流路には、上部に未反応ガス供給マニホールド４６及び既反応ガス排出マニホールド４７が設けられ、下部に未反応ガス排出マニホールド４８と、第１及び第２の既反応ガス供給マニホールド４９，５０が共通して設けられている。また、それぞれの流路には、金属メッシュからなる矩形のガス流路が形成されている。
【００４５】
上述したように、複数の交換セルのうち、一部のセルは、未反応ガス流路１２と第１の既反応ガス流路１３ａが組合わされて使用され、残りのセルは、未反応ガス流路１２と第２の既反応ガス流路１３ｂが組合わされて使用されている。 また、図７に示すように、積層された交換セルの両端部にはエンドプレート５１が設けられており、左のエンドプレート５１ａには、未反応ガス入口５２及び既反応ガス出口５３が設けられ、右のエンドプレート５１ｂには、未反応ガス出口５４と、第１及び第２の既反応ガス入口５５，５６が設けられている。また、図８及び図９に示すように、第１及び第２の既反応ガス流路の既反応ガス排出マニホールド４７は共通になっており、第１及び第２の既反応ガス流路を流れてきた既反応ガスは、同じマニホールドを介して排出される。
【００４６】
図１１は、前記切替弁４１及び開閉弁４５を制御するための未反応ガス温度と既反応ガス温度の関係を示す図である。
すなわち、温湿度交換手段１１では、未反応ガス温度Ｔｄ、すなわち未反応ガス出口露点と、既反応ガス温度Ｔｗ、すなわち既反応ガス入口露点は、比例関係にある（Ｔｗ＝Ｂ（Ｔｄ））。そして、第２の既反応ガス流路１３ｂへの通路の開閉弁４５を閉じた場合には、未反応ガス温度と既反応ガス温度の関係は、図１１中の曲線Ｔｗ＝Ｂ（Ｔｄ）となる。一方、第２の既反応ガス流路１３ｂへの通路の開閉弁４５を開いた場合には、未反応ガス温度と既反応ガス温度の関係は、図１１中の曲線Ｔｗ＝Ｃ（Ｔｄ）となる。すなわち、開閉弁４５を開くと、すべての交換セルで加湿が行われるため、同じ既反応ガス温度でも高い未反応ガス温度が得られる。
【００４７】
一方、燃料電池本体では、反応による生成水が反応ガス中に蒸発し、燃料ガスの入口／出口の水蒸気の差分とともに排出空気に含まれる。生成水が効率良く排出されるためには、既反応ガス温度Ｔｗと未反応ガス温度Ｔｄは、既反応ガス中の水蒸気量が、未反応ガス中の水蒸気量と、生成水と、燃料ガス入口／出口の水蒸気量の差分との和と等しくなる関係、すなわち１対１の関係である必要がある（Ｔｗ＝Ａ（Ｔｄ））。
【００４８】
図１１に示したように、曲線が重なる点Ａでは、温湿度交換手段１１で加湿された未反応ガスの温度Ｔｄにおいて含まれる水蒸気量と、生成水と、燃料ガス入口／出口の水蒸気量の差分との和が、温湿度交換手段１１に供給される既反応ガスの温度Ｔｗにおいて含まれる水蒸気量と等しくなり、生成水を効率良く排出できて、定常な運転が可能となる。
【００４９】
［３−２．作用］
上記のような構成を有する本実施形態の作用を、図１２に示したフローチャートにしたがって説明する。
図１２に示したように、制御開始時には、切替弁４１は既反応ガス流路側へ開かれ、また、開閉弁４５は閉じられており、温湿度交換手段１１の複数のセルのうち、第１の既反応ガス流路１３ａを備える交換セルにおいて、既反応ガスから未反応ガスへ加湿が行われる。残りの交換セルには既反応ガスは供給されず、このセルを流れる未反応ガスは加湿されずにそのまま通過する。
【００５０】
そして、ステップ１２０１において、前記コントロールユニット４４によって、既反応ガス温度センサ４２及び未反応ガス温度センサ４３の検出結果が監視され、Ｔｗ＜Ａ（Ｔｄ）−ΔＴｗ１の条件を満足しない場合、すなわち、既反応ガス温度が所定の値以上である場合には、ステップ１２０５に進む。
一方、既反応ガス温度がＴｗ＜Ａ（Ｔｄ）−ΔＴｗ１の条件を満足した場合、すなわち、図１１のＢ点のように、既反応ガス温度が、燃料電池本体のバランス曲線Ｔｗ＝Ａ（Ｔｄ）より下の領域に推移すると、ステップ１２０２に進み、バイパス通路４０へ切り替わる。なお、この場合、図１１に示すように、バランス曲線に対して所定の幅ΔＴｗ１を設定し、この幅より下回るときにバイパス通路へ切り替わるようにすると、切り替えの回数を少なくできる。
【００５１】
このようにして、バイパス通路４０へ切り替わると、既反応ガスが温湿度交換手段１１に供給されなくなるため、未反応ガスへの加湿が行われなくなり、図１１のＢ点→Ｃ点のように、未反応ガス温度が低下していく。
そして、ステップ１２０３において、前記コントロールユニット４４によって、既反応ガス温度センサ４２及び未反応ガス温度センサ４３の検出結果が監視され、Ｔｗ≧Ａ（Ｔｄ）＋ΔＴｗ１の条件を満足しない場合、すなわち、既反応ガス温度が所定の値以下である場合には、そのまま運転が行われる。
【００５２】
そして、未反応ガス温度がさらに低下し、図１１のＤ点のように、既反応ガス温度が、燃料電池本体のバランス曲線Ｔｗ＝Ａ（Ｔｄ）よりも上の領域に推移すると、ステップ１２０４に進み、再び既反応ガス通路へ切り替えられる。その結果、既反応ガスが温湿度供給手段１１に供給されて、未反応ガスを加湿し、図１１のＤ点→Ｃ点のように、未反応ガス温度が上昇する。なお、ここでも、バランス曲線に対して所定の制御幅ΔＴｗ１を設置している。
【００５３】
また、ステップ１２０５においては、前記コントロールユニット４４によって、既反応ガス温度センサ４２及び未反応ガス温度センサ４３の検出結果が監視され、Ｔｗ＞Ａ（Ｔｄ）＋ΔＴｗ２の条件を満足しない場合、すなわち、既反応ガス温度が所定の値以下である場合には、ステップ１２０１に戻り、運転が続けられる。
一方、既反応ガス温度がＴｗ＞Ａ（Ｔｄ）＋ΔＴｗ２の条件を満足した場合、すなわち、図１１のＥ点のように、既反応ガス温度が、燃料電池本体のバランス曲線Ｔｗ＝Ａ（Ｔｄ）より上の領域に推移すると、ステップ１２０６に進み、開閉弁４５が開かれる。この時、図１１に示すように、バランス曲線に対して所定の幅ΔＴｗ２を設定し、この幅より下回るときに開閉弁が開くようにすると、開閉の回数を少なくできる。
【００５４】
このようにして、開閉弁４５が開かれると、第１の既反応ガス流路１３ａとともに、第２の既反応ガス流路１３ｂへも既反応ガスが供給され、すべての交換セルで未反応ガスが加湿されるため、加湿量が増加し、図１１中のＥ点→Ｆ点のように、未反応ガス温度が上昇していく。
【００５５】
そして、ステップ１２０７において、前記コントロールユニット４４によって、既反応ガス温度センサ４２及び未反応ガス温度センサ４３の検出結果が監視され、Ｔｗ≦Ａ（Ｔｄ）−ΔＴｗ２の条件を満足しない場合、すなわち、既反応ガス温度が所定の値以上である場合には、そのまま運転が行われる。
【００５６】
一方、未反応ガス温度がさらに上昇し、図１１のＧ点のように、既反応ガス温度が、燃料電池本体のバランス曲線Ｔｗ＝Ａ（Ｔｄ）よりも下の領域に推移すると、ステップ１２０８に進み、再び開閉弁４５が閉じられ、第１の既反応ガス流路１３ａのみに既反応ガスが供給されるため、加湿量が減少し、図１１のＧ点→Ｆ点のように、未反応ガス温度が低下する。ここでも、バランス曲線に対して所定の制御幅ΔＴｗ２を設置している。
【００５７】
以上の制御フローを繰り返すことにより、温湿度交換手段のバランス曲線を外れて加湿量が増加しても、燃料電池本体のバランス曲線上のＣ点に保つ制御を行うことができる。また、温湿度交換手段の交換セルを２通りに使用することにより、加湿量が減少しても、燃料電池本体のバランス曲線上のＦ点に保つ制御を行うことができる。
【００５８】
また、本実施形態の燃料電池システムと、従来のバイパス通路及び開閉弁をもたない燃料電池システムを用意し、冷却水により燃料電池本体の温度を変化させて発電試験を行ったところ、以下のような結果が得られた。
まず、未反応ガス温度が６５℃、既反応ガス温度が７０℃となるように発電試験を行ったところ、燃料電池本体の水バランスと、温湿度交換手段のバランスが一致し、２つのシステムとも安定した運転が可能であった（図１１のＡ点に相当する）。
【００５９】
次に、既反応ガス温度が６５℃となるように燃料電池本体の温度を下げて試験を行ったところ、従来の燃料電池システムでは、未反応ガス温度が６０℃となるように温湿度交換手段がバランスした。ところが、この条件では、未反応ガス温度に対して既反応ガス温度が低く、燃料電池本体で生成水を十分に排出できず、電極内に水が蓄積してガスの拡散を阻害し、運転を行うことができなかった（図１１のＢ点に相当する）。
一方、本実施形態の燃料電池システムでは、切替弁を制御することにより、燃料電池本体で水がバランスする点、すなわち既反応ガス温度が６５℃、未反応ガス温度が５０℃で運転を行うことができ、継続して運転が可能となった（図１１のＣ点に相当する）。
【００６０】
次に、既反応ガス温度が７５℃となるように燃料電池本体の温度を上げて試験を行ったところ、従来の燃料電池システムでは、未反応ガス温度が７０℃となるように温湿度交換手段がバランスした。ところが、この条件では、未反応ガス温度に対して既反応ガス温度が高く、燃料電池本体で生成水の量以上の水蒸気が排出され、電解質膜中の水分が減少して抵抗が増加し、運転を行うことができなかった（図１１のＥ点に相当する）。
一方、本実施形態の燃料電池システムでは、開閉弁を制御することにより、燃料電池本体で水がバランスする点、すなわち既反応ガス温度が７５℃、未反応ガス温度が７２℃で運転を行うことができ、継続して運転が可能となった（図１１のＦ点に相当する）。
【００６１】
［３−３．効果］
このように、本実施形態によれば、温湿度交換手段の既反応ガス流路の入口と出口を結ぶバイパス通路と、このバイパス通路へ切り替える切替弁と、未反応ガス温度センサ及び既反応ガス温度センサを設け、既反応ガス温度センサと未反応ガス温度センサの検出結果に基づいて、切替弁の切り替え動作を制御することによって、燃料電池本体での水がバランスする条件での運転が可能となる。
【００６２】
また、温湿度交換手段を複数の交換セルで構成し、複数の交換セルのうち、一部の交換セルに流通する第１の既反応ガス通路と、残りの交換セルに流通する第２の既反応ガス通路と、第２の既反応ガス通路を開閉する弁を設け、開閉弁を制御することで、加湿量を増加させることが可能となり、加湿量が不足した時にも加湿量を増加させて、燃料電池本体での水がバランスする条件での運転が可能となる。
【００６３】
なお、本実施形態では、検出手段として温度センサを用いたが、湿度センサや露点計で代用しても同様の効果が得られる。また、バイパス流路への切替を切替弁を用いて行ったが、バイパス流路と既反応ガス流路の一方もしくは両方に開閉弁を設けても同様の効果が得られる。
【００６４】
［４．第４実施形態］
［４−１．構成］
図１３は、本発明に係る固体高分子型燃料電池システムの第４実施形態の構成を示す図である。すなわち、本実施形態においても、第３実施形態と同様に、温湿度交換手段１１が複数の交換セルから構成され、これら複数の交換セルのうち、一部の交換セルに流通する第１の未反応ガス流路１２ａと、残りの交換セルに流通する第２の未反応ガス流路１２ｂが設けられ、さらに、前記第２の未反応ガス流路１２ｂを開閉する開閉弁６５が設けられている。
また、温湿度交換手段１１の未反応ガス流路の入口と出口を結ぶバイパス通路６０が設けられ、コンプレッサ１０から温湿度交換手段１１の未反応ガス流路１２へ至るライン上に、前記バイパス通路６０へ切り替える切替弁６１が設けられている。また、燃料電池の酸化剤極２から温湿度交換手段１１の既反応ガス流路１３へ至るライン上に、既反応ガス温度センサ６２が設けられ、また、温湿度交換手段１１の未反応ガス流路１２から燃料電池の酸化剤極２へ至るライン上に、未反応ガス温度センサ６３が設けられている。また、前記既反応ガス温度センサ６２と未反応ガス温度センサ６３の検出結果に基づいて、前記切替弁６１及び開閉弁６５の動作を制御するコントロールユニット６４が設けられている。
【００６５】
図１４は、本実施形態の温湿度交換手段のセル積層方向の断面図を示したものである。すなわち、温湿度交換手段１１は複数の交換セルで構成され、各交換セルは、第１の未反応ガス流路１２ａ、保水性多孔質体１４及び既反応ガス流路１３、あるいは、第２の未反応ガス流路１２ｂ、保水性多孔質体１４及び既反応ガス流路１３から構成されている。
【００６６】
また、図１５は第１の未反応ガス流路１２ａ、図１６は第２の未反応ガス流路１２ｂ、図１７は既反応ガス流路１３を示したものである。図に示したように、それぞれの流路には、上部に第１及び第２の未反応ガス供給マニホールド６６、６７及び既反応ガス排出マニホールド６８が設けられ、下部に未反応ガス排出マニホールド６９と、既反応ガス供給マニホールド７０が共通して設けられている。また、それぞれの流路には、金属メッシュからなる矩形のガス流路が形成されている。
【００６７】
上述したように、複数の交換セルのうち、一部のセルは、既反応ガス流路１３と第１の未反応ガス流路１２ａが組合わされて使用され、残りのセルは、既反応ガス流路１３と第２の未反応ガス流路１２ｂが組合わされて使用されている。
また、図１４に示すように、積層された交換セルの両端部にはエンドプレート７１が設けられており、左のエンドプレート７１ａには、第１及び第２の未反応ガス入口７２、７３及び既反応ガス出口７４が設けられ、右のエンドプレート７１ｂには、未反応ガス出口７５と、既反応ガス入口７６が設けられている。また、図１５及び図１６に示すように、第１及び第２の未反応ガス流路の未反応ガス排出マニホールド６９は共通になっており、第１及び第２の未反応ガス流路を流れてきた未反応ガスは、同じマニホールドを介して排出される。
【００６８】
図１１は、前記切替弁６１及び開閉弁６５を制御するための未反応ガス温度と既反応ガス温度の関係を示す図である。
すなわち、温湿度交換手段１１では、未反応ガス温度Ｔｄ、すなわち未反応ガス出口露点と、既反応ガス温度Ｔｗ、すなわち既反応ガス入口露点は、比例関係にある（Ｔｗ＝Ｂ（Ｔｄ））。そして、第２の未反応ガス流路１２ｂへの通路の開閉弁６５を閉じた場合には、未反応ガス温度と既反応ガス温度の関係は、図１１中の曲線Ｔｗ＝Ｂ（Ｔｄ）となる。一方、第２の未反応ガス流路１２ｂへの通路の開閉弁６５を開いた場合には、未反応ガス温度と既反応ガス温度の関係は、図１１中の曲線Ｔｗ＝Ｃ（Ｔｄ）となる。すなわち、開閉弁６５を開くと、すべての交換セルで加湿が行われるため、同じ既反応ガス温度でも高い未反応ガス温度が得られる。
【００６９】
［４−２．作用］
上記のような構成を有する本実施形態の作用を、図１８に示したフローチャートにしたがって説明する。
図１８に示したように、制御開始時には、切替弁６１は未反応ガス流路側へ開かれ、また、開閉弁６５は閉じられており、温湿度交換手段１１の複数のセルのうち、第１の未反応ガス流路１２ａを備える交換セルにおいて、既反応ガスから未反応ガスへ加湿が行われる。一方、残りの交換セルには未反応ガスは供給されないので、加湿は行われない。
【００７０】
そして、ステップ１８０１において、前記コントロールユニット６４によって、既反応ガス温度センサ６２及び未反応ガス温度センサ６３の検出結果が監視され、Ｔｗ＜Ａ（Ｔｄ）−ΔＴｗ１の条件を満足しない場合、すなわち、既反応ガス温度が所定の値以上である場合には、ステップ１８０５に進む。
一方、既反応ガス温度がＴｗ＜Ａ（Ｔｄ）−ΔＴｗ１の条件を満足した場合、すなわち、図１１のＢ点のように、既反応ガス温度が、燃料電池本体のバランス曲線Ｔｗ＝Ａ（Ｔｄ）より下の領域に推移すると、ステップ１８０２に進み、バイパス通路６０へ切り替わる。なお、この場合、図１１に示すように、バランス曲線に対して所定の幅ΔＴｗ１を設定し、この幅より下回るときにバイパス通路へ切り替わるようにすると、切り替えの回数を少なくできる。
【００７１】
このようにして、バイパス通路６０へ切り替わると、未反応ガスが温湿度交換手段１１に供給されなくなるため、未反応ガスへの加湿が行われなくなり、図１１のＢ点→Ｃ点のように、未反応ガス温度が低下していく。
そして、ステップ１８０３において、前記コントロールユニット６４によって、既反応ガス温度センサ６２及び未反応ガス温度センサ６３の検出結果が監視され、Ｔｗ≧Ａ（Ｔｄ）＋ΔＴｗ１の条件を満足しない場合、すなわち、既反応ガス温度が所定の値以下である場合には、そのまま運転が行われる。
【００７２】
そして、未反応ガス温度がさらに低下し、図１１のＤ点のように、既反応ガス温度が、燃料電池本体のバランス曲線Ｔｗ＝Ａ（Ｔｄ）よりも上の領域に推移すると、ステップ１８０４に進み、再び未反応ガス通路へ切り替えられる。その結果、未反応ガスが温湿度供給手段１１に供給され、未反応ガスが加湿されるので、図１１のＤ点→Ｃ点のように、未反応ガス温度が上昇する。なお、ここでも、バランス曲線に対して所定の制御幅ΔＴｗ１を設置している。
【００７３】
また、ステップ１８０５においては、前記コントロールユニット６４によって、既反応ガス温度センサ６２及び未反応ガス温度センサ６３の検出結果が監視され、Ｔｗ＞Ａ（Ｔｄ）＋ΔＴｗ２の条件を満足しない場合、すなわち、既反応ガス温度が所定の値以下である場合には、ステップ１８０１に戻る。
一方、既反応ガス温度がＴｗ＞Ａ（Ｔｄ）＋ΔＴｗ２の条件を満足した場合、すなわち、図１１のＥ点のように、既反応ガス温度が、燃料電池本体のバランス曲線Ｔｗ＝Ａ（Ｔｄ）より上の領域に推移すると、ステップ１８０６に進み、開閉弁６５が開かれる。この時、図１１に示すように、バランス曲線に対して所定の幅ΔＴｗ２を設定し、この幅より下回るときに開閉弁が開くようにすると、開閉の回数を少なくできる。
【００７４】
このようにして、開閉弁６５が開かれると、第１の未反応ガス流路１２ａとともに、第２の未反応ガス流路１２ｂへも未反応ガスが供給され、すべての交換セルで未反応ガスが加湿されるため、加湿量が増加し、図１１中のＥ点→Ｆ点のように、未反応ガス温度が上昇していく。
【００７５】
そして、ステップ１８０７において、前記コントロールユニット６４によって、既反応ガス温度センサ６２及び未反応ガス温度センサ６３の検出結果が監視され、Ｔｗ≦Ａ（Ｔｄ）−ΔＴｗ２の条件を満足しない場合、すなわち、既反応ガス温度が所定の値以上である場合には、そのまま運転が行われる。
【００７６】
一方、未反応ガス温度がさらに上昇し、図１１のＧ点のように、既反応ガス温度が、燃料電池本体のバランス曲線Ｔｗ＝Ａ（Ｔｄ）よりも下の領域に推移すると、ステップ１８０８に進み、再び開閉弁６５が閉じられ、第１の未反応ガス流路１２ａのみに未反応ガスが供給されるため、加湿量が減少し、図１１のＧ点→Ｆ点のように、未反応ガス温度が低下する。ここでも、バランス曲線に対して所定の制御幅ΔＴｗ２を設置している。
【００７７】
以上の制御フローを繰り返すことにより、温湿度交換手段のバランス曲線を外れて加湿量が増加しても、燃料電池本体のバランス曲線上のＣ点に保つ制御を行うことができる。また、温湿度交換手段の交換セルを２通りに使用することにより、加湿量が減少しても、燃料電池本体のバランス曲線上のＦ点に保つ制御を行うことができる。
【００７８】
また、第３実施形態と同様に、本実施形態の燃料電池システムと、従来のバイパス通路及び開閉弁をもたない燃料電池システムを用意し、冷却水により燃料電池本体の温度を変化させて発電試験を行ったところ、以下のような結果が得られた。
まず、未反応ガス温度が６５℃、既反応ガス温度が７０℃となるように発電試験を行ったところ、燃料電池本体の水バランスと、温湿度交換手段のバランスが一致し、２つのシステムとも安定した運転が可能であった。
【００７９】
次に、既反応ガス温度が６５℃となるように燃料電池本体の温度を下げて試験を行ったところ、本実施形態の燃料電池システムでは、切替弁の制御により、燃料電池本体で水がバランスする点、すなわち既反応ガス温度が６５℃、未反応ガス温度が５０℃で運転を行うことができ、継続して運転が可能となった。
【００８０】
次に、既反応ガス温度が７５℃となるように燃料電池本体の温度を上げて試験を行ったところ、本実施形態の燃料電池システムでは、開閉弁を制御することにより、燃料電池本体で水がバランスする点、すなわち既反応ガス温度が７５℃、未反応ガス温度が７２℃で運転を行うことができ、継続して運転が可能となった。
【００８１】
［４−３．効果］
このように、本実施形態によれば、温湿度交換手段の未反応ガス流路の入口と出口を結ぶバイパス通路と、このバイパス通路へ切り替える切替弁と、未反応ガス温度センサ及び既反応ガス温度センサを設け、既反応ガス温度センサと未反応ガス温度センサの検出結果に基づいて、切替弁の切り替え動作を制御することによって、燃料電池本体での水がバランスする条件での運転が可能となる。
【００８２】
また、温湿度交換手段を複数の交換セルで構成し、複数の交換セルのうち、一部の交換セルに流通する第１の未反応ガス通路と、残りの交換セルに流通する第２の未反応ガス通路と、第２の未反応ガス通路を開閉する弁を設け、この開閉弁を制御することで、加湿量を増加させることが可能となり、加湿量が不足した時にも加湿量を増加させて、燃料電池本体での水がバランスする条件での運転が可能となる。
【００８３】
なお、本実施形態では、検出手段として温度センサを用いたが、湿度センサや露点計で代用しても同様の効果が得られる。また、バイパス流路への切替を切替弁を用いて行ったが、バイパス流路と既反応ガス流路の一方もしくは両方に開閉弁を設けても同様の効果が得られる。
【００８４】
［５．第５実施形態］
本実施形態は、上記第３実施形態の変形例であり、既反応ガス流路を第１の既反応ガス流路と第２の既反応ガス流路とから構成し、未反応ガス流路と既反応ガス流路の間に保水性の多孔質体を配置したものである。
【００８５】
［５−１．構成］
図１９は、本発明に係る固体高分子型燃料電池システムの第５実施形態の構成を示す図である。すなわち、本実施形態においては、既反応ガス流路１３が第１の既反応ガス流路１３ａと第２の既反応ガス流路１３ｂとから構成され、互いに隣接して配置されたすべての未反応ガス流路１２と第１又は第２の既反応ガス流路１３ａ、１３ｂの間に、保水性の多孔質体１４が配設されている。その他の構成は、第３実施形態の図７と同様であるので説明は省略する。
【００８６】
［５−２．作用・効果］
図２０は、第２の既反応ガス流路１３ｂの開閉弁を閉じた時の作動状態を示したものである。この場合、既反応ガスは１つおきに流れ、その両側にある保水性の多孔質体１４を介して未反応ガスを加湿する。したがって、未反応ガス流路１個に対して保水性の多孔質体１個が有効となり、加湿を行う。
【００８７】
また、図１９は、第２の既反応ガス流路１３ｂの開閉弁を開いた時の作動状態を示したものである。この場合、既反応ガスはすべての既反応ガス流路を流れ、その両側にある保水性の多孔質体１４を介して未反応ガスを加湿する。したがって、未反応ガス流路１個に対して保水性の多孔質体２個が有効となり、加湿を行うため、交換面積が２倍となり、加湿量を増やすことが可能となる。
【００８８】
このように、本実施形態の温湿度交換手段を用いることにより、加湿量の増加が可能となり、第３実施形態と同様の効果が得られる。また、各流路の両側に保水性の多孔質体を配するため、温湿度交換手段のコンパクト化が可能となり、開閉弁を閉じて第１の既反応ガス流路だけを用いる時にも、全ての未反応ガスが加湿され、安定した動作が可能となる。
【００８９】
［６．第６実施形態］
本実施形態は、上記第４実施形態の変形例であり、未反応ガス流路を第１の未反応ガス流路と第２の未反応ガス流路とから構成し、未反応ガス流路と既反応ガス流路の間に保水性の多孔質体を配置したものである。
【００９０】
［６−１．構成］
図２１は、本発明に係る固体高分子型燃料電池システムの第６実施形態の構成を示す図である。すなわち、本実施形態においては、未反応ガス流路１２が第１の未反応ガス流路１２ａと第２の未反応ガス流路１２ｂとから構成され、互いに隣接して配置されたすべての第１又は第２の未反応ガス流路１２ａ、１２ｂと既反応ガス流路１３の間に、保水性の多孔質体１４が配設されている。その他の構成は、第４実施形態の図１４と同様であるので説明は省略する。
【００９１】
［６−２．作用・効果］
図２２は、第２の未反応ガス流路１２ｂの開閉弁を閉じた時の作動状態を示したものである。この場合、未反応ガスは１つおきに流れ、その両側にある保水性の多孔質体１４を介して、既反応ガスによって加湿される。したがって、未反応ガス流路１個に対して保水性の多孔質体２個が有効となり、加湿が行われる。
【００９２】
また、図２１は、第２の未反応ガス流路１２ｂの開閉弁を開いた時の作動状態を示したものである。この場合、未反応ガスはすべての未反応ガス流路を流れ、その両側にある保水性の多孔質体１４を介して、既反応ガスによって加湿される。したがって、未反応ガス流路１個に対して保水性の多孔質体２個が有効となる。この場合、図２２に示した開閉弁を閉じた時と比べて、未反応ガス流路１個に対する保水性多孔質体の個数は２個と同じだが、１個の未反応ガス流路を流れるガス量が半分となるため、加湿量を増やすことが可能となる。
【００９３】
このように、本実施形態の温湿度交換手段を用いることにより、加湿量の増加が可能となり、第４実施形態と同様の効果が得られる。また、各流路の両側に保水性の多孔質体を配するため、温湿度交換手段のコンパクト化が可能となり、開閉弁を閉じて第１の未反応ガス流路だけを用いる時にも、全ての未反応ガスが加湿され、安定した動作が可能となる。
【００９４】
［７．参考例］
［７−１．構成］
図２３に示したように、本参考例においては、温湿度交換手段１１に、不凍液を用いた温度調整手段８０が設けられている。この温度調整手段８０は、冷却水ポンプ７の出口で分岐されたラインに、開閉弁８１を介して接続されている。また、燃料電池の酸化剤極２から温湿度交換手段１１の既反応ガス流路１３へ至るライン上に、既反応ガス温度センサ８２が設けられ、また、温湿度交換手段１１の未反応ガス流路１２から燃料電池の酸化剤極２へ至るライン上に、未反応ガス温度センサ８３が設けられている。また、前記既反応ガス温度センサ８２と未反応ガス温度センサ８３の検出結果に基づいて、前記開閉弁８１の開閉動作を制御するコントロールユニット８４が設けられている。
【００９５】
［７−２．作用・効果］
上記のような構成を有する本参考例においては、既反応ガス温度センサ８２と未反応ガス温度センサ８３の検出結果に基づいて、温湿度交換手段１１を冷却する必要がある場合には、開閉弁８１が開かれ、温湿度交換手段１１の温度調整手段８０に不凍液が供給される。不凍液が供給されると、温湿度交換手段１１が冷却されて、未反応ガス温度が低下する。したがって、図２に示した関係に基づいて、開閉弁８１の開閉が制御されることにより、燃料電池本体での水がバランスする条件での運転が可能となる。
【００９６】
【発明の効果】
以上述べたように、本発明によれば、温湿度交換手段における加湿量を適切に制御することができる、高性能の固体高分子型燃料電池システムを提供することができる。
【図面の簡単な説明】
【図１】 本発明の固体高分子型燃料電池システムの第１実施形態の構成を示す図
【図２】 第１実施形態及び第２実施形態の燃料電池システムの制御曲線を示す図
【図３】 第１実施形態の動作を示すフローチャート
【図４】 本発明の固体高分子型燃料電池システムの第２実施形態の構成を示す図
【図５】 第２実施形態の動作を示すフローチャート
【図６】 本発明の固体高分子型燃料電池システムの第３実施形態の構成を示す図
【図７】 第３実施形態の温湿度交換手段の構成を示す縦断面図
【図８】 第３実施形態の温湿度交換手段の第１の既反応ガス流路の構成を示す平面図
【図９】 第３実施形態の温湿度交換手段の第２の既反応ガス流路の構成を示す平面図
【図１０】 第３実施形態の温湿度交換手段の未反応ガス流路の構成を示す平面図
【図１１】 第３実施形態及び第４実施形態の燃料電池システムの制御曲線を示す図
【図１２】 第３実施形態の動作を示すフローチャート
【図１３】 本発明の固体高分子型燃料電池システムの第４実施形態の構成を示す図
【図１４】 第４実施形態の温湿度交換手段の構成を示す縦断面図
【図１５】 第４実施形態の温湿度交換手段の第１の未反応ガス流路の構成を示す平面図
【図１６】 第４実施形態の温湿度交換手段の第２の未反応ガス流路の構成を示す平面図
【図１７】 第４実施形態の温湿度交換手段の既反応ガス流路の構成を示す平面図
【図１８】 第４実施形態の動作を示すフローチャート
【図１９】 第５実施形態の温湿度交換手段の構成を示す縦断面図であって、第２の既反応ガス流路の開閉弁を開いた状態を示す図
【図２０】 第５実施形態の温湿度交換手段の構成を示す縦断面図であって、第２の既反応ガス流路の開閉弁を閉じた状態を示す図
【図２１】 第６実施形態の温湿度交換手段の構成を示す縦断面図であって、第２の未反応ガス流路の開閉弁を開いた状態を示す図
【図２２】 第６実施形態の温湿度交換手段の構成を示す縦断面図であって、第２の未反応ガス流路の開閉弁を閉じた状態を示す図
【図２３】 固体高分子型燃料電池システムの参考例の構成を示す図
【図２４】 従来の固体高分子型燃料電池システムの構成を示す図[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polymer electrolyte fuel cell system, and more particularly to a polymer electrolyte fuel cell system that has been improved to appropriately control the amount of humidification in a temperature and humidity exchange means.
[0002]
[Prior art]
A fuel cell is a device that directly converts chemical energy of a fuel into electrical energy by electrochemically reacting a fuel such as hydrogen with an oxidant such as air. Depending on the type of electrolyte used, this fuel cell is roughly classified into low-temperature operating fuel cells such as alkaline, solid polymer, and phosphoric acid, and high-temperature operating fuel cells such as molten carbonate and solid oxide. Is done.
Among them, a polymer electrolyte fuel cell (hereinafter referred to as PEFC) using a proton-conducting polymer electrolyte membrane as an electrolyte can be operated with a simple system and high power density with a compact structure. Therefore, it is attracting attention as a power source for space and vehicles.
[0003]
A general fuel cell system uses a hydrocarbon such as methane or an alcohol such as methanol as a fuel, a reformer that reforms the fuel to generate a hydrogen-rich gas, a shift reactor that reduces CO in the hydrogen-rich gas, and a selection It consists of an oxidizer, a compressor that supplies air as an oxidant, a cooling system that removes heat generated by the cell reaction, and a fuel cell body. In the fuel cell body, hydrogen ions are generated from hydrogen contained in the fuel gas, and the hydrogen ions are conducted through the electrolyte membrane and react with oxygen contained in the oxidant gas to produce water. At that time, a part of the chemical energy of hydrogen is directly taken out as electric energy.
[0004]
Further, since the electrolyte membrane exhibits good hydrogen ion conductivity in a water-containing state, it is indispensable to humidify the electrolyte membrane to keep it in a water-containing state during operation. This humidification method includes an external humidification method in which water vapor is previously added to the reaction gas, indirect internal humidification in which battery cooling water and unreacted gas are brought into contact with each other through a humidifying film, and a part of the battery cooling water is added to the unreacted gas. There are known a method, a direct internal humidification method in which battery cooling water is directly supplied to a reaction gas in a battery reaction part, and the like.
[0005]
On the other hand, in recent years, the pre-reacted gas that has passed through the battery unit and the unreacted gas before passing through the battery unit are brought into contact with each other through a water vapor permeable membrane, and moisture contained in the pre-reacted gas is removed by the partial pressure difference of the water vapor. (JF McElroy and LJ Nuttall, "Status of Solid Polymer Electrolyte Technology and Potential for Transportation Applications", 17th IECEC, 1982, pp.667-671.).
In this case, since water vapor is generated with the electrode reaction, the already-reacted gas contains saturated or near water vapor. On the other hand, since there is little water vapor contained in the unreacted gas, a water vapor partial pressure difference is generated in each gas, and the concentration of water vapor can be diffused using this as a driving force. As described in the above-mentioned document, this method is characterized in that it does not cause a phase change. JP-A-6-132038 also discloses a similar humidification method.
[0006]
FIG. 24 is a diagram showing a configuration of a general solid polymer fuel cell system used conventionally. That is, the polymer electrolyte fuel cell main body is configured by sandwiching a solid polymer electrolyte membrane 3 having ion conductivity and a gas separation function between a pair of gas diffusion electrodes including a fuel electrode 1 and an oxidant electrode 2. Yes. When a fuel gas such as hydrogen is supplied to the fuel electrode 1 and an oxidant gas such as air is supplied to the oxidant electrode 2, an electromotive force is generated by an electrochemical reaction. Since this electrochemical reaction is an exothermic reaction, the fuel cell body is provided with a cooling water plate 4 in which cooling water is circulated in order to remove excess heat.
[0007]
A fuel reformer 5 that reforms the fuel to generate a hydrogen rich gas and a CO reducer 6 that reduces CO in the hydrogen rich gas are provided so that the reformed fuel gas is supplied to the fuel electrode 1. It is configured. After a predetermined amount of this fuel gas is consumed by the cell reaction, it is supplied as a fuel exhaust gas to the burner of the reformer 5 and becomes a heat source for the reformer.
[0008]
On the other hand, the cooling water plate 4 of the fuel cell is configured to be supplied with antifreeze by a cooling water pump 7. The antifreeze supplied to the cooling water plate 4 is cooled by the fan 8 and circulated after removing heat generated by the battery reaction. An antifreeze liquid reservoir tank 9 is connected to the inlet of the fan 8 so as to adjust the amount of antifreeze liquid.
[0009]
Further, the air supplied by the compressor 10 is configured to be supplied to the oxidant electrode 2 of the fuel cell through the unreacted gas flow path 12 of the temperature / humidity exchanging means 11. After a predetermined amount of this oxidant gas is consumed by the battery reaction, the generated water generated by the battery reaction is recovered and discharged out of the battery. The discharged air is supplied to the already-reacted gas flow path 13 of the temperature / humidity exchanging means 11, gives moisture to unreacted air through the water-retaining porous body 14, humidifies the unreacted air, and then oxidizer It is configured to be discharged out of the system as exhaust gas.
[0010]
[Problems to be solved by the invention]
However, the conventional humidification method as described above has various problems as described below.
That is, in the method of adding moisture to the unreacted gas by adding the water vapor of the already reacted gas through the water vapor permeable membrane, humidification is performed only by the difference in water vapor partial pressure between the two gases. Diffusion resistance, diffusion resistance in the water vapor permeable membrane, and diffusion resistance on the unreacted gas side become extremely large, so the problem is that a large humidifier is required for sufficient humidification. There is.
[0011]
Further, in this method, the humidification amount is determined by the amount of water vapor contained in the already-reacted gas and the exchange area of the porous body serving as a medium. Usually, since the exchange area of the porous body is constant, the humidification amount is It depends on the amount of water vapor contained in the gas, that is, the water vapor partial pressure.
Although the water vapor partial pressure varies depending on operating conditions such as temperature and output, it is necessary to control so as to obtain a necessary amount of humidification under any operating conditions. This is because when the required amount of humidification cannot be obtained, the moisture in the electrolyte membrane decreases, the hydrogen ion conductivity decreases, and the performance decreases. Furthermore, since the moisture in the already reacted gas that has passed through the reaction section is reduced and the water vapor partial pressure is lowered, there is a possibility that a vicious cycle occurs in which the humidification amount is further reduced.
[0012]
As described above, in the method of adding moisture to the unreacted gas by adding the water vapor of the already reacted gas through the water vapor permeable membrane, the humidification amount is determined by the partial pressure of water vapor in the already reacted gas, so that the amount of humidification is balanced. If it goes out of the state, there is a problem that it is difficult to control the humidification amount.
[0013]
The present invention has been proposed in order to solve the above-described problems of the prior art, and its purpose is to provide a high-performance solid-state high-capacity, capable of appropriately controlling the amount of humidification in the temperature / humidity exchange means. The object is to provide a molecular fuel cell system.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, the invention described in claim 1 is directed to a solid polymer fuel cell stack using a solid polymer membrane as an electrolyte, a reaction gas already passed through a reaction part of the fuel cell stack, and the reaction. In a polymer electrolyte fuel cell system having temperature and humidity exchange means for exchanging heat and moisture with unreacted gas before passing through the section, an inlet side and an outlet of an already reacted gas channel of the temperature and humidity exchange means Forming a bypass passage connecting the sides, providing a switching valve to the bypass passage, a first detection means for detecting the temperature or humidity of the already reacted gas that has passed through the reaction section, and before passing through the reaction section And a second detection means for detecting the temperature or humidity of the unreacted gas, and a balance of the temperature and humidity exchange means showing a proportional relationship between the unreacted gas temperature detected by each of the detection means and the already-reacted gas temperature. Curves and In order for the generated water to be discharged efficiently, the amount of water vapor in the existing reaction gas is equal to the sum of the amount of water vapor in the unreacted gas and the difference between the amount of water vapor in the generated water and the fuel gas inlet and outlet. Based on the battery water balance curve indicating the relationship between the gas temperature and the unreacted gas temperature, the switching valve is controlled when the already reacted gas temperature falls below the already reacted gas temperature on the battery water balance curve. Flowing the already reacted gas into the bypass passage; afterwards, When the already-reacted gas temperature becomes equal to or higher than the already-reacted gas temperature on the battery water balance curve, the switching valve is controlled to close the bypass passage and to flow the already-reacted gas to the already-reacted gas passage. And According to the first aspect of the present invention having the above-described configuration, the switching valve to the bypass passage connecting the inlet side and the outlet side of the existing reaction gas flow path is controlled to be supplied to the temperature / humidity exchange means. Since the flow rate of the already reacted gas can be adjusted, the humidification amount of the unreacted gas can be easily controlled.
[0015]
The invention according to claim 2 is a polymer electrolyte fuel cell stack having a solid polymer membrane as an electrolyte, an already reacted gas that has passed through a reaction part of the fuel cell stack, and an unreacted state before passing through the reaction part. In the polymer electrolyte fuel cell system having a temperature / humidity exchanging means for exchanging heat and moisture with gas, a bypass passage connecting the inlet side and the outlet side of the unreacted gas flow path of the temperature / humidity exchanging means is formed, A switching valve to the bypass passage is provided to detect the temperature or humidity of the already-reacted gas that has passed through the reaction unit, and the temperature or humidity of the unreacted gas before passing through the reaction unit. And a balance curve of the temperature / humidity exchanging means showing the proportional relationship between the unreacted gas temperature detected by each of the detecting means and the already-reacted gas temperature, and the generated water is efficiently discharged. Be done In order to make the amount of water vapor in the already reacted gas equal to the sum of the amount of water vapor in the unreacted gas and the difference between the amount of water vapor in the generated water and the fuel gas inlet and outlet, the already reacted gas temperature and the unreacted gas temperature. And the unreacted gas to the bypass passage by controlling the switching valve when the existing reaction gas temperature falls below the existing reaction gas temperature on the battery water balance curve. Shed afterwards, When the already-reacted gas temperature is equal to or higher than the already-reacted gas temperature on the battery water balance curve, the switching valve is controlled to close the bypass passage and allow the unreacted reaction gas to flow into the unreacted gas passage. Features. According to the second aspect of the present invention having the above-described configuration, the switching valve to the bypass passage connecting the inlet side and the outlet side of the unreacted gas flow path is controlled to be supplied to the temperature / humidity exchange means. Since the flow rate of the unreacted gas can be adjusted, the humidification amount of the unreacted gas can be easily controlled.
[0016]
According to the invention described in claim 1 or claim 2 as described above, Since the switching valve to the bypass passage for the already-reacted gas flow path or the switching valve to the bypass path for the unreacted gas flow path can be controlled, the humidification amount in the temperature / humidity exchange means can be controlled more accurately. It becomes possible.
[0017]
According to a third aspect of the present invention, in the polymer electrolyte fuel cell system according to the first aspect, the temperature / humidity exchange means includes a plurality of replacement cells, and a part of the plurality of replacement cells. An open / close valve that opens and closes the second pre-reacted gas flow path is provided with a first pre-reacted gas flow path that flows through the exchange cell and a second pre-reacted gas flow path that flows through the remaining exchange cells. The open / close valve is opened when the existing reaction gas temperature exceeds the existing reaction gas temperature on the battery water balance curve, based on the balance curve of the temperature / humidity exchange means and the battery water balance curve. Flowing the already-reacted gas into the second already-reacted gas channel, afterwards, The already-reacted gas temperature is not more than the already-reacted gas temperature on the battery water balance curve Became In this case, the on-off valve is closed, and the already-reacted gas is allowed to flow only to the first already-reacted gas channel. According to the invention of claim 3 having the above-described configuration, when the temperature / humidity exchanging means is composed of a plurality of exchange cells, the first pre-reacted gas flow path and the second pre-reacted gas are provided. Since the flow rate of the already-reacted gas supplied to the temperature / humidity exchanging means can be adjusted by controlling the open / close valve that opens and closes the second already-reacted gas channel, the humidification of the unreacted gas The amount can be easily controlled.
[0018]
According to a fourth aspect of the present invention, in the polymer electrolyte fuel cell system according to the second aspect, the temperature / humidity exchanging means includes a plurality of replacement cells, and a part of the plurality of replacement cells. A first unreacted gas flow path that circulates in the exchange cell and a second unreacted gas flow path that circulates in the remaining exchange cells, and an open / close valve that opens and closes the second unreacted gas flow path The open / close valve is opened when the existing reaction gas temperature exceeds the existing reaction gas temperature on the battery water balance curve, based on the balance curve of the temperature / humidity exchange means and the battery water balance curve. Flowing the unreacted gas into the second unreacted gas flow path, afterwards, The already-reacted gas temperature is not more than the already-reacted gas temperature on the battery water balance curve Became In this case, the open / close valve is closed, and the unreacted gas flows only to the first unreacted gas flow path. According to invention of Claim 4 which has the above structures, when a temperature / humidity exchange means is comprised from the several exchange cell, it is the 1st unreacted gas flow path and the 2nd unreacted gas. The flow rate of the unreacted gas supplied to the temperature / humidity exchanging means can be adjusted by providing the flow path and controlling the on-off valve that opens and closes the second unreacted gas flow path. The amount can be easily controlled.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention (hereinafter referred to as embodiments) will be specifically described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the member same as the conventional type shown in FIG. 24, and description is abbreviate | omitted.
[0022]
[1. First Embodiment]
[1-1. Constitution]
FIG. 1 is a diagram showing the configuration of a first embodiment of a polymer electrolyte fuel cell system according to the present invention. That is, in the present embodiment, a bypass passage 20 that connects the inlet and the outlet of the already-reacted gas flow path 13 of the temperature / humidity exchange means 11 is provided, and the already-reacted gas of the temperature / humidity exchange means 11 from the oxidant electrode 2 of the fuel cell. On the line leading to the flow path 13, a switching valve 21 for switching to the bypass passage 20 and a reaction gas temperature sensor 22 are provided. An unreacted gas temperature sensor 23 is provided on a line from the unreacted gas flow path 12 of the temperature / humidity exchange means 11 to the oxidant electrode 2 of the fuel cell. Further, a control unit 24 for controlling the switching operation of the switching valve 21 based on the detection results of the already-reacted gas temperature sensor 22 and the unreacted gas temperature sensor 23 is provided.
[0023]
FIG. 2 is a diagram showing the relationship between the unreacted gas temperature and the already-reacted gas temperature for controlling the switching operation of the switching valve 21. That is, in the temperature / humidity exchanging means 11, the unreacted gas temperature Td, that is, the unreacted gas outlet dew point, and the already-reacted gas temperature Tw, that is, the already-reacted gas inlet dew point, are in a proportional relationship (Tw = B (Td)).
On the other hand, in the fuel cell main body, the water produced by the reaction evaporates into the reaction gas and is included in the exhaust air together with the difference in the water vapor at the inlet / outlet of the fuel gas. In order to efficiently discharge the generated water, the already-reacted gas temperature Tw and the unreacted gas temperature Td are determined based on the amount of water vapor in the already-reacted gas, the amount of water-vapor in the unreacted gas, the generated water, and the fuel gas inlet. / A relationship that is equal to the sum of the difference in water vapor amount at the outlet, that is, a one-to-one relationship (Tw = A (Td)).
[0024]
As shown in FIG. 2, at the point A where these two curves overlap, the amount of water vapor contained at the temperature Td of the unreacted gas humidified by the temperature / humidity exchanging means 11, the generated water, and the fuel gas inlet / outlet The sum of the difference in the amount of water vapor becomes equal to the amount of water vapor contained in the temperature Tw of the already-reacted gas supplied to the temperature / humidity exchanging means 11, so that the produced water can be discharged efficiently and steady operation is possible.
[0025]
[1-2. Action]
The operation of the present embodiment having the above configuration will be described according to the flowchart shown in FIG.
As shown in FIG. 3, at the start of control, the switching valve 21 is opened to the already-reacted gas flow path side, and humidification is performed from the already-reacted gas to the unreacted gas by the temperature / humidity exchanging means 11.
[0026]
In step 301, the control unit 24 monitors the detection results of the already-reacted gas temperature sensor 22 and the unreacted gas temperature sensor 23. If the condition Tw <A (Td) −ΔTw is not satisfied, When the reaction gas temperature is equal to or higher than a predetermined value, the operation is performed as it is.
On the other hand, when the already-reacted gas temperature satisfies the condition of Tw <A (Td) −ΔTw, that is, as shown by the point B in FIG. 2, the already-reacted gas temperature is the balance curve Tw = A (Td ), The process proceeds to step 302 to switch to the bypass passage 20. In this case, as shown in FIG. 2, if a predetermined width ΔTw is set for the balance curve and switching to the bypass passage is made when the width is less than this width, the number of times of switching can be reduced.
[0027]
In this way, when switching to the bypass passage 20, the already-reacted gas is not supplied to the temperature / humidity exchanging means 11, so that the unreacted gas is not humidified, and the points B to C in FIG. Unreacted gas temperature decreases.
In step 303, the control unit 24 monitors the detection results of the already-reacted gas temperature sensor 22 and the unreacted gas temperature sensor 23. If the condition of Tw ≧ A (Td) + ΔTw is not satisfied, When the gas temperature is below a predetermined value, the operation is performed as it is.
[0028]
Then, when the temperature of the unreacted gas further decreases and the temperature of the already reacted gas shifts to a region above the balance curve Tw = A (Td) of the fuel cell main body as indicated by point D in FIG. Proceed and switch to the already reacted gas passage again. As a result, the already-reacted gas is supplied to the temperature / humidity supply means 11 to humidify the unreacted gas, and the unreacted gas temperature rises as point D → C in FIG. In this case as well, a predetermined control width ΔTw is set for the balance curve.
By repeating the above control flow, even if the balance curve of the temperature / humidity exchanging means deviates, it is possible to perform control to keep the point C on the balance curve of the fuel cell body.
[0029]
Moreover, when the fuel cell system of the present embodiment and the conventional fuel cell system without a bypass passage were prepared and the power generation test was performed by changing the temperature of the fuel cell main body with cooling water, the following results were obtained. was gotten.
First, when a power generation test was performed so that the unreacted gas temperature was 65 ° C. and the already-reacted gas temperature was 70 ° C., the water balance of the fuel cell body and the balance of the temperature / humidity exchange means matched, and both systems Stable operation was possible (corresponding to point A in FIG. 2).
[0030]
Next, a test was conducted by lowering the temperature of the fuel cell main body so that the temperature of the already reacted gas was 65 ° C. In the conventional fuel cell system, the temperature / humidity exchange means was set so that the temperature of the unreacted gas became 60 ° C. Balanced. However, under these conditions, the temperature of the reacted gas is lower than the temperature of the unreacted gas, and the generated water cannot be sufficiently discharged from the fuel cell main body. This could not be done (corresponding to point B in FIG. 2).
On the other hand, in the fuel cell system of the present embodiment, by controlling the switching valve, the water is balanced in the fuel cell body, that is, the operation is performed at the existing reaction gas temperature of 65 ° C. and the unreacted gas temperature of 50 ° C. And continued operation was possible (corresponding to point C in FIG. 2).
[0031]
[1-3. effect]
Thus, according to the present embodiment, the bypass passage connecting the inlet and the outlet of the already-reacted gas flow path of the temperature / humidity exchange means, the switching valve for switching to this bypass passage, the unreacted gas temperature sensor, and the already-reacted gas temperature By providing a sensor and controlling the switching operation of the switching valve based on the detection results of the already-reacted gas temperature sensor and the unreacted gas temperature sensor, the fuel cell main body can be operated under a condition where water is balanced. .
[0032]
In the present embodiment, the temperature sensor is used as the detection means, but the same effect can be obtained even if a humidity sensor or a dew point meter is used instead. In addition, the switching to the bypass channel is performed using the switching valve, but the same effect can be obtained by providing an open / close valve in one or both of the bypass channel and the already-reacted gas channel.
[0033]
[2. Second Embodiment]
[2-1. Constitution]
FIG. 4 is a diagram showing the configuration of the second embodiment of the polymer electrolyte fuel cell system according to the present invention. That is, in the present embodiment, a bypass passage 30 that connects the inlet and the outlet of the unreacted gas flow path 12 of the temperature / humidity exchange means 11 is provided, and reaches from the compressor 10 to the unreacted gas flow path 12 of the temperature / humidity exchange means 11. A switching valve 31 for switching to the bypass passage 30 is provided on the line. Similarly to the first embodiment, the already-reacted gas temperature sensor 32 is provided on the line from the oxidant electrode 2 of the fuel cell to the already-reacted gas flow path 13 of the temperature / humidity exchanging means 11. An unreacted gas temperature sensor 33 is provided on the line from the unreacted gas flow path 12 of the exchange means 11 to the oxidant electrode 2 of the fuel cell. Further, a control unit 34 for controlling the switching operation of the switching valve 31 based on the detection results of the already-reacted gas temperature sensor 32 and the unreacted gas temperature sensor 33 is provided.
[0034]
[2-2. Action]
The operation of the present embodiment having the above configuration will be described with reference to the flowchart shown in FIG.
As shown in FIG. 5, at the start of the control, the switching valve 31 is opened to the unreacted gas flow path side, and humidification is performed from the already reacted gas to the unreacted gas by the temperature / humidity exchanging means 11.
[0035]
In step 501, the detection results of the already-reacted gas temperature sensor 32 and the unreacted gas temperature sensor 33 are monitored by the control unit 34. If the condition of Tw <A (Td) −ΔTw is not satisfied, When the reaction gas temperature is equal to or higher than a predetermined value, the operation is performed as it is.
On the other hand, when the already-reacted gas temperature satisfies the condition of Tw <A (Td) −ΔTw, that is, as shown by the point B in FIG. 2, the already-reacted gas temperature is the balance curve Tw = A (Td ), The process proceeds to step 502 to switch to the bypass passage 30. In this case as well, as shown in FIG. 2, if the predetermined width ΔTw is set for the balance curve and switching to the bypass passage is made when the width is smaller than this width, the number of times of switching can be reduced.
[0036]
Thus, when switching to the bypass passage 30, the unreacted gas is not supplied to the temperature / humidity exchanging means 11, so that the unreacted gas is not humidified, and the point B → C in FIG. Unreacted gas temperature decreases.
In step 503, the control unit 34 monitors the detection results of the already-reacted gas temperature sensor 32 and the unreacted gas temperature sensor 33. If the condition of Tw ≧ A (Td) + ΔTw is not satisfied, that is, the already-reacted When the gas temperature is below a predetermined value, the operation is performed as it is.
[0037]
Then, when the temperature of the unreacted gas further decreases and the temperature of the already-reacted gas transitions to a region above the balance curve Tw = A (Td) of the fuel cell main body as indicated by point D in FIG. Proceed and switch to the unreacted gas passage again. As a result, the unreacted gas is supplied to the temperature / humidity supply means 11 and humidified, and the temperature of the unreacted gas rises as indicated by point D → point C in FIG. In this case as well, a predetermined control width ΔTw is set for the balance curve.
By repeating the above control flow, even if the balance curve of the temperature / humidity exchanging means deviates, it is possible to perform control to keep the point C on the balance curve of the fuel cell body.
[0038]
Similarly to the first embodiment, the fuel cell system of this embodiment and a conventional fuel cell system without a bypass passage are prepared, and a power generation test is performed by changing the temperature of the fuel cell main body with cooling water. As a result, the following results were obtained.
First, when a power generation test was performed so that the unreacted gas temperature was 65 ° C. and the already-reacted gas temperature was 70 ° C., the water balance of the fuel cell body and the balance of the temperature / humidity exchange means matched, and both systems Stable operation was possible.
[0039]
Next, a test was conducted by lowering the temperature of the fuel cell main body so that the temperature of the already reacted gas was 65 ° C. In the fuel cell system of the present embodiment, water was detected in the fuel cell main body by controlling the switching valve. Are balanced, that is, the operation can be performed at an already reacted gas temperature of 65 ° C. and an unreacted gas temperature of 50 ° C., and the operation can be continued.
[0040]
[2-3. effect]
Thus, according to the present embodiment, the bypass passage connecting the inlet and the outlet of the unreacted gas flow path of the temperature / humidity exchange means, the switching valve for switching to the bypass passage, the unreacted gas temperature sensor, and the already reacted gas temperature. By providing a sensor and controlling the switching operation of the switching valve based on the detection results of the already-reacted gas temperature sensor and the unreacted gas temperature sensor, the fuel cell main body can be operated under a condition where water is balanced. .
[0041]
In the present embodiment, the temperature sensor is used as the detection means, but the same effect can be obtained even if a humidity sensor or a dew point meter is used instead. In addition, the switching to the bypass channel is performed using the switching valve, but the same effect can be obtained by providing an opening / closing valve in one or both of the bypass channel and the already-reacted gas channel.
[0042]
[3. Third Embodiment]
[3-1. Constitution]
FIG. 6 is a diagram showing the configuration of the third embodiment of the polymer electrolyte fuel cell system according to the present invention. That is, in the present embodiment, the temperature / humidity exchanging means 11 is composed of a plurality of exchange cells, and among the plurality of exchange cells, the first already-reacted gas flow path 13a that circulates to some of the exchange cells, and the remaining A second already-reacted gas channel 13b that circulates in the exchange cell is provided, and an on-off valve 45 that opens and closes the second already-reacted gas channel 13b is provided.
Further, a bypass passage 40 connecting the inlet and the outlet of the already-reacted gas flow path of the temperature / humidity exchange means 11 is provided, and on the line from the oxidant electrode 2 of the fuel cell to the already-reacted gas flow path 13 of the temperature / humidity exchange means 11. Further, a switching valve 41 for switching to the bypass passage 40 and an already-reacted gas temperature sensor 42 are provided. An unreacted gas temperature sensor 43 is provided on the line from the unreacted gas flow path 12 of the temperature / humidity exchange means 11 to the oxidant electrode 2 of the fuel cell. A control unit 44 is provided for controlling the operation of the switching valve 41 and the on-off valve 45 based on the detection results of the already-reacted gas temperature sensor 42 and the unreacted gas temperature sensor 43.
[0043]
FIG. 7 shows a cross-sectional view in the cell stacking direction of the temperature and humidity exchanging means of this embodiment. That is, the temperature / humidity exchanging means 11 is composed of a plurality of exchange cells, and each exchange cell includes the unreacted gas channel 12, the water-retaining porous body 14, the first already-reacted gas channel 13a, or the unreacted gas. It is comprised from the flow path 12, the water retention porous body 14, and the 2nd existing reaction gas flow path 13b.
[0044]
8 shows the first already-reacted gas channel 13a, FIG. 9 shows the second already-reacted gas channel 13b, and FIG. 10 shows the unreacted gas channel 12. As shown in the figure, each channel is provided with an unreacted gas supply manifold 46 and an already-reacted gas discharge manifold 47 in the upper part, and an unreacted gas discharge manifold 48 and first and second already-removed manifolds in the lower part. Reaction gas supply manifolds 49 and 50 are provided in common. Each channel is formed with a rectangular gas channel made of a metal mesh.
[0045]
As described above, some of the plurality of exchange cells are used in combination with the unreacted gas flow path 12 and the first pre-reacted gas flow path 13a, and the remaining cells are unreacted gas flow. The path 12 and the second already-reacted gas flow path 13b are used in combination. Further, as shown in FIG. 7, end plates 51 are provided at both ends of the stacked exchange cells, and an unreacted gas inlet 52 and a previously reacted gas outlet 53 are provided in the left end plate 51a. The right end plate 51b is provided with an unreacted gas outlet 54 and first and second already-reacted gas inlets 55 and 56. Further, as shown in FIGS. 8 and 9, the already-reacted gas discharge manifold 47 of the first and second already-reacted gas flow paths is common, and flows through the first and second already-reacted gas flow paths. The already reacted gas that has been discharged is discharged through the same manifold.
[0046]
FIG. 11 is a diagram showing the relationship between the unreacted gas temperature and the previously reacted gas temperature for controlling the switching valve 41 and the on-off valve 45.
That is, in the temperature / humidity exchanging means 11, the unreacted gas temperature Td, that is, the unreacted gas outlet dew point, and the already-reacted gas temperature Tw, that is, the already-reacted gas inlet dew point, are in a proportional relationship (Tw = B (Td)). When the on-off valve 45 of the passage to the second already-reacted gas channel 13b is closed, the relationship between the unreacted gas temperature and the already-reacted gas temperature is expressed by the curve Tw = B (Td) in FIG. Become. On the other hand, when the on-off valve 45 of the passage to the second already-reacted gas channel 13b is opened, the relationship between the unreacted gas temperature and the already-reacted gas temperature is expressed by the curve Tw = C (Td) in FIG. Become. That is, when the on-off valve 45 is opened, humidification is performed in all the exchange cells, so that a high unreacted gas temperature can be obtained even at the same already-reacted gas temperature.
[0047]
On the other hand, in the fuel cell main body, the water produced by the reaction evaporates into the reaction gas and is included in the exhaust air together with the difference in the water vapor at the inlet / outlet of the fuel gas. In order to efficiently discharge the generated water, the already-reacted gas temperature Tw and the unreacted gas temperature Td are determined based on the amount of water vapor in the already-reacted gas, the amount of water-vapor in the unreacted gas, the generated water, and the fuel gas inlet. / A relationship that is equal to the sum of the difference in water vapor amount at the outlet, that is, a one-to-one relationship (Tw = A (Td)).
[0048]
As shown in FIG. 11, at the point A where the curves overlap, the amount of water vapor contained in the temperature Td of the unreacted gas humidified by the temperature / humidity exchanging means 11, the generated water, and the amount of water vapor at the fuel gas inlet / outlet The sum of the difference becomes equal to the amount of water vapor contained in the temperature Tw of the existing reaction gas supplied to the temperature / humidity exchange means 11, and the produced water can be discharged efficiently, so that steady operation is possible.
[0049]
[3-2. Action]
The operation of the present embodiment having the above configuration will be described with reference to the flowchart shown in FIG.
As shown in FIG. 12, at the start of the control, the switching valve 41 is opened to the already-reacted gas flow path side, and the on-off valve 45 is closed, and the first of the plurality of cells of the temperature / humidity exchange means 11 is closed. In the exchange cell including the already-reacted gas channel 13a, humidification is performed from the already-reacted gas to the unreacted gas. Already reacted gas is not supplied to the remaining exchange cells, and unreacted gas flowing through this cell passes through without being humidified.
[0050]
In step 1201, the control unit 44 monitors the detection results of the already-reacted gas temperature sensor 42 and the unreacted gas temperature sensor 43. If the condition Tw <A (Td) −ΔTw1 is not satisfied, If the reaction gas temperature is equal to or higher than the predetermined value, the process proceeds to step 1205.
On the other hand, when the already-reacted gas temperature satisfies the condition of Tw <A (Td) −ΔTw1, that is, as shown by the point B in FIG. 11, the already-reacted gas temperature is the balance curve Tw = A (Td ), The process proceeds to step 1202 and switches to the bypass passage 40. In this case, as shown in FIG. 11, if the predetermined width ΔTw1 is set for the balance curve, and the switching is made to the bypass passage when the width is smaller than this width, the number of times of switching can be reduced.
[0051]
In this way, when switching to the bypass passage 40, the already-reacted gas is not supplied to the temperature / humidity exchanging means 11, so that the unreacted gas is not humidified, and the point B → C in FIG. Unreacted gas temperature decreases.
In step 1203, the detection results of the already-reacted gas temperature sensor 42 and the unreacted gas temperature sensor 43 are monitored by the control unit 44, and when the condition of Tw ≧ A (Td) + ΔTw1 is not satisfied, that is, When the gas temperature is below a predetermined value, the operation is performed as it is.
[0052]
Then, when the temperature of the unreacted gas further decreases and the temperature of the already-reacted gas transitions to a region above the balance curve Tw = A (Td) of the fuel cell main body as indicated by point D in FIG. Proceed and switch to the already reacted gas passage again. As a result, the already-reacted gas is supplied to the temperature / humidity supply means 11 to humidify the unreacted gas, and the unreacted gas temperature rises as point D → C in FIG. In this case as well, a predetermined control width ΔTw1 is set for the balance curve.
[0053]
In step 1205, the control unit 44 monitors the detection results of the already-reacted gas temperature sensor 42 and the unreacted gas temperature sensor 43. If the condition of Tw> A (Td) + ΔTw2 is not satisfied, If the reaction gas temperature is equal to or lower than the predetermined value, the process returns to step 1201 and the operation is continued.
On the other hand, when the already-reacted gas temperature satisfies the condition of Tw> A (Td) + ΔTw2, that is, as shown by point E in FIG. 11, the already-reacted gas temperature is the balance curve Tw = A (Td) of the fuel cell body. If it changes to the area | region higher, it will progress to step 1206 and the on-off valve 45 will be opened. At this time, as shown in FIG. 11, if the predetermined width ΔTw2 is set for the balance curve and the on-off valve is opened when the width is less than this width, the number of times of opening and closing can be reduced.
[0054]
Thus, when the on-off valve 45 is opened, the already-reacted gas is supplied to the second already-reacted gas channel 13b together with the first already-reacted gas channel 13a. Is humidified, the amount of humidification increases, and the temperature of the unreacted gas rises from point E to point F in FIG.
[0055]
In step 1207, the control unit 44 monitors the detection results of the already-reacted gas temperature sensor 42 and the unreacted gas temperature sensor 43, and when the condition of Tw ≦ A (Td) −ΔTw2 is not satisfied, When the reaction gas temperature is equal to or higher than a predetermined value, the operation is performed as it is.
[0056]
On the other hand, when the unreacted gas temperature further rises and the already-reacted gas temperature shifts to a region below the balance curve Tw = A (Td) of the fuel cell main body as indicated by point G in FIG. Then, the on-off valve 45 is closed again, and the already-reacted gas is supplied only to the first already-reacted gas flow path 13a, so that the amount of humidification decreases and unreacted as indicated by the points G → F in FIG. The gas temperature decreases. Again, a predetermined control width ΔTw2 is set for the balance curve.
[0057]
By repeating the above control flow, even if the humidification amount increases outside the balance curve of the temperature / humidity exchange means, it is possible to perform control to keep the point C on the balance curve of the fuel cell body. Further, by using two exchange cells of the temperature and humidity exchange means, it is possible to perform control to keep the point F on the balance curve of the fuel cell main body even when the humidification amount is reduced.
[0058]
In addition, when the fuel cell system of this embodiment and a conventional fuel cell system without a bypass passage and an on-off valve were prepared and a power generation test was performed by changing the temperature of the fuel cell body with cooling water, the following was performed. The result was obtained.
First, when a power generation test was performed so that the unreacted gas temperature was 65 ° C. and the already-reacted gas temperature was 70 ° C., the water balance of the fuel cell body and the balance of the temperature / humidity exchange means matched, and both systems Stable operation was possible (corresponding to point A in FIG. 11).
[0059]
Next, a test was conducted by lowering the temperature of the fuel cell main body so that the temperature of the already reacted gas was 65 ° C. In the conventional fuel cell system, the temperature / humidity exchange means was set so that the temperature of the unreacted gas became 60 ° C. Balanced. However, under these conditions, the temperature of the reacted gas is lower than the temperature of the unreacted gas, and the generated water cannot be sufficiently discharged from the fuel cell main body. This could not be done (corresponding to point B in FIG. 11).
On the other hand, in the fuel cell system of the present embodiment, by controlling the switching valve, the water is balanced in the fuel cell body, that is, the operation is performed at the existing reaction gas temperature of 65 ° C. and the unreacted gas temperature of 50 ° C. And continued operation was possible (corresponding to point C in FIG. 11).
[0060]
Next, a test was performed by raising the temperature of the fuel cell main body so that the temperature of the already reacted gas was 75 ° C. In the conventional fuel cell system, the temperature / humidity exchange means was set so that the temperature of the unreacted gas became 70 ° C. Balanced. However, under this condition, the reacted gas temperature is higher than the unreacted gas temperature, water vapor exceeding the amount of generated water is discharged from the fuel cell body, the moisture in the electrolyte membrane decreases, the resistance increases, and the operation Could not be performed (corresponding to point E in FIG. 11).
On the other hand, in the fuel cell system of the present embodiment, by controlling the on-off valve, water is balanced in the fuel cell main body, that is, the operation is performed at an existing reaction gas temperature of 75 ° C. and an unreacted gas temperature of 72 ° C. And continued operation was possible (corresponding to point F in FIG. 11).
[0061]
[3-3. effect]
Thus, according to the present embodiment, the bypass passage connecting the inlet and the outlet of the already-reacted gas flow path of the temperature / humidity exchange means, the switching valve for switching to this bypass passage, the unreacted gas temperature sensor, and the already-reacted gas temperature By providing a sensor and controlling the switching operation of the switching valve based on the detection results of the already-reacted gas temperature sensor and the unreacted gas temperature sensor, the fuel cell main body can be operated under a condition where water is balanced. .
[0062]
In addition, the temperature / humidity exchanging means is constituted by a plurality of exchange cells, and among the plurality of exchange cells, the first already-reacted gas passage that circulates to some of the exchange cells and the second existing gas that circulates to the remaining exchange cells. By providing a valve that opens and closes the reaction gas passage and the second already-reacted gas passage, the amount of humidification can be increased by controlling the on-off valve. When the humidification amount is insufficient, the humidification amount is increased. In addition, the fuel cell main body can be operated under a condition where water is balanced.
[0063]
In the present embodiment, the temperature sensor is used as the detection means, but the same effect can be obtained even if a humidity sensor or a dew point meter is used instead. In addition, the switching to the bypass channel is performed using the switching valve, but the same effect can be obtained by providing an opening / closing valve in one or both of the bypass channel and the already-reacted gas channel.
[0064]
[4. Fourth Embodiment]
[4-1. Constitution]
FIG. 13 is a diagram showing the configuration of the fourth embodiment of the polymer electrolyte fuel cell system according to the present invention. That is, also in the present embodiment, as in the third embodiment, the temperature / humidity exchanging means 11 is composed of a plurality of exchange cells, and among the plurality of exchange cells, the first uncirculated cells that are distributed to some of the exchange cells. A reactive gas flow channel 12a and a second unreacted gas flow channel 12b flowing through the remaining exchange cells are provided, and an open / close valve 65 for opening and closing the second unreacted gas flow channel 12b is provided. .
Further, a bypass passage 60 connecting the inlet and the outlet of the unreacted gas flow path of the temperature / humidity exchange means 11 is provided, and the bypass passage is provided on a line from the compressor 10 to the unreacted gas flow path 12 of the temperature / humidity exchange means 11. A switching valve 61 for switching to 60 is provided. A pre-reacted gas temperature sensor 62 is provided on the line from the oxidant electrode 2 of the fuel cell to the pre-reacted gas flow path 13 of the temperature / humidity exchange means 11, and the unreacted gas flow of the temperature / humidity exchange means 11 is provided. An unreacted gas temperature sensor 63 is provided on a line from the path 12 to the oxidant electrode 2 of the fuel cell. Further, a control unit 64 for controlling the operation of the switching valve 61 and the on-off valve 65 based on the detection results of the already-reacted gas temperature sensor 62 and the unreacted gas temperature sensor 63 is provided.
[0065]
FIG. 14 shows a cross-sectional view in the cell stacking direction of the temperature and humidity exchanging means of the present embodiment. That is, the temperature / humidity exchanging means 11 is composed of a plurality of exchange cells, and each exchange cell includes the first unreacted gas flow path 12a, the water-retaining porous body 14, the already-reacted gas flow path 13, or the second The unreacted gas channel 12b, the water-retaining porous body 14, and the already-reacted gas channel 13 are configured.
[0066]
FIG. 15 shows the first unreacted gas flow path 12a, FIG. 16 shows the second unreacted gas flow path 12b, and FIG. As shown in the figure, each flow path is provided with first and second unreacted gas supply manifolds 66 and 67 and an already reacted gas discharge manifold 68 at the upper part, and an unreacted gas discharge manifold 69 at the lower part. The already-reacted gas supply manifold 70 is provided in common. Each channel is formed with a rectangular gas channel made of a metal mesh.
[0067]
As described above, some of the plurality of exchange cells are used in combination with the already-reacted gas channel 13 and the first unreacted gas channel 12a, and the remaining cells are the already-reacted gas flow. The passage 13 and the second unreacted gas passage 12b are used in combination.
Further, as shown in FIG. 14, end plates 71 are provided at both ends of the stacked exchange cells. The left end plate 71a has first and second unreacted gas inlets 72, 73 and A pre-reacted gas outlet 74 is provided, and an unreacted gas outlet 75 and a pre-reacted gas inlet 76 are provided in the right end plate 71b. Further, as shown in FIGS. 15 and 16, the unreacted gas discharge manifold 69 of the first and second unreacted gas channels is common, and flows through the first and second unreacted gas channels. Unreacted gas that has been discharged is discharged through the same manifold.
[0068]
FIG. 11 is a diagram showing the relationship between the unreacted gas temperature and the previously reacted gas temperature for controlling the switching valve 61 and the on-off valve 65.
That is, in the temperature / humidity exchanging means 11, the unreacted gas temperature Td, that is, the unreacted gas outlet dew point, and the already-reacted gas temperature Tw, that is, the already-reacted gas inlet dew point, are in a proportional relationship (Tw = B (Td)). When the opening / closing valve 65 of the passage to the second unreacted gas flow path 12b is closed, the relationship between the unreacted gas temperature and the already-reacted gas temperature is expressed by the curve Tw = B (Td) in FIG. Become. On the other hand, when the opening / closing valve 65 of the passage to the second unreacted gas channel 12b is opened, the relationship between the unreacted gas temperature and the already-reacted gas temperature is expressed by the curve Tw = C (Td) in FIG. Become. That is, when the on-off valve 65 is opened, humidification is performed in all the exchange cells, so that a high unreacted gas temperature can be obtained even with the same already-reacted gas temperature.
[0069]
[4-2. Action]
The operation of the present embodiment having the above configuration will be described with reference to the flowchart shown in FIG.
As shown in FIG. 18, at the start of control, the switching valve 61 is opened to the unreacted gas flow path side, and the on-off valve 65 is closed, and the first of the plurality of cells of the temperature / humidity exchanging means 11 is closed. In the exchange cell including the unreacted gas flow path 12a, humidification is performed from the already reacted gas to the unreacted gas. On the other hand, since the unreacted gas is not supplied to the remaining exchange cells, humidification is not performed.
[0070]
In step 1801, the detection results of the already-reacted gas temperature sensor 62 and the unreacted gas temperature sensor 63 are monitored by the control unit 64, and when the condition of Tw <A (Td) −ΔTw1 is not satisfied, If the reaction gas temperature is equal to or higher than the predetermined value, the process proceeds to step 1805.
On the other hand, when the already-reacted gas temperature satisfies the condition of Tw <A (Td) −ΔTw1, that is, as shown by the point B in FIG. 11, the already-reacted gas temperature is the balance curve Tw = A (Td ), The process proceeds to step 1802 and switches to the bypass passage 60. In this case, as shown in FIG. 11, if the predetermined width ΔTw1 is set for the balance curve, and the switching is made to the bypass passage when the width is smaller than this width, the number of times of switching can be reduced.
[0071]
In this way, when switching to the bypass passage 60, the unreacted gas is not supplied to the temperature / humidity exchanging means 11, so that the unreacted gas is not humidified, as indicated by point B → C in FIG. Unreacted gas temperature decreases.
In step 1803, the detection results of the already-reacted gas temperature sensor 62 and the unreacted gas temperature sensor 63 are monitored by the control unit 64, and when the condition of Tw ≧ A (Td) + ΔTw1 is not satisfied, that is, When the gas temperature is below a predetermined value, the operation is performed as it is.
[0072]
Then, when the temperature of the unreacted gas further decreases and the temperature of the already reacted gas shifts to a region above the balance curve Tw = A (Td) of the fuel cell main body as indicated by point D in FIG. Proceed and switch to the unreacted gas passage again. As a result, the unreacted gas is supplied to the temperature / humidity supply means 11 and the unreacted gas is humidified, so that the temperature of the unreacted gas rises as point D → point C in FIG. In this case as well, a predetermined control width ΔTw1 is set for the balance curve.
[0073]
In step 1805, the control unit 64 monitors the detection results of the already-reacted gas temperature sensor 62 and the unreacted gas temperature sensor 63. If the condition of Tw> A (Td) + ΔTw2 is not satisfied, If the reaction gas temperature is equal to or lower than the predetermined value, the process returns to step 1801.
On the other hand, when the already-reacted gas temperature satisfies the condition of Tw> A (Td) + ΔTw2, that is, as shown by point E in FIG. 11, the already-reacted gas temperature is the balance curve Tw = A (Td) of the fuel cell body. When the region moves to a higher region, the process proceeds to step 1806, where the on-off valve 65 is opened. At this time, as shown in FIG. 11, if the predetermined width ΔTw2 is set for the balance curve and the on-off valve is opened when the width is less than this width, the number of times of opening and closing can be reduced.
[0074]
Thus, when the on-off valve 65 is opened, the unreacted gas is supplied to the second unreacted gas flow path 12b as well as the first unreacted gas flow path 12a. Is humidified, the amount of humidification increases, and the temperature of the unreacted gas rises from point E to point F in FIG.
[0075]
In step 1807, the control unit 64 monitors the detection results of the already-reacted gas temperature sensor 62 and the unreacted gas temperature sensor 63. If the condition of Tw ≦ A (Td) −ΔTw2 is not satisfied, When the reaction gas temperature is equal to or higher than a predetermined value, the operation is performed as it is.
[0076]
On the other hand, when the unreacted gas temperature further rises and the already-reacted gas temperature shifts to a region below the balance curve Tw = A (Td) of the fuel cell main body as indicated by point G in FIG. Then, the on-off valve 65 is closed again, and the unreacted gas is supplied only to the first unreacted gas flow path 12a. Therefore, the amount of humidification decreases, and unreacted as indicated by point G → point F in FIG. The gas temperature decreases. Again, a predetermined control width ΔTw2 is set for the balance curve.
[0077]
By repeating the above control flow, even if the humidification amount increases outside the balance curve of the temperature / humidity exchange means, it is possible to perform control to keep the point C on the balance curve of the fuel cell body. Further, by using two exchange cells of the temperature and humidity exchange means, it is possible to perform control to keep the point F on the balance curve of the fuel cell main body even when the humidification amount is reduced.
[0078]
Similarly to the third embodiment, the fuel cell system of the present embodiment and a conventional fuel cell system having no bypass passage and on / off valve are prepared, and the temperature of the fuel cell body is changed by cooling water to generate power. When the test was conducted, the following results were obtained.
First, when a power generation test was performed so that the unreacted gas temperature was 65 ° C. and the already-reacted gas temperature was 70 ° C., the water balance of the fuel cell body and the balance of the temperature / humidity exchange means matched, and both systems Stable operation was possible.
[0079]
Next, a test was performed with the temperature of the fuel cell body lowered so that the temperature of the existing reaction gas was 65 ° C. In the fuel cell system of this embodiment, water was balanced in the fuel cell body by controlling the switching valve. That is, the operation can be performed at a temperature of already reacted gas of 65 ° C. and a temperature of unreacted gas of 50 ° C., and the operation can be continued.
[0080]
Next, a test was conducted by raising the temperature of the fuel cell main body so that the temperature of the already reacted gas was 75 ° C. In the fuel cell system of the present embodiment, the water on the fuel cell main body was controlled by controlling the on-off valve. Are balanced, that is, the operation can be performed at an already reacted gas temperature of 75 ° C. and an unreacted gas temperature of 72 ° C., and the operation can be continued.
[0081]
[4-3. effect]
Thus, according to the present embodiment, the bypass passage connecting the inlet and the outlet of the unreacted gas flow path of the temperature / humidity exchange means, the switching valve for switching to the bypass passage, the unreacted gas temperature sensor, and the already reacted gas temperature. By providing a sensor and controlling the switching operation of the switching valve based on the detection results of the already-reacted gas temperature sensor and the unreacted gas temperature sensor, the fuel cell main body can be operated under a condition where water is balanced. .
[0082]
Further, the temperature / humidity exchange means is constituted by a plurality of exchange cells, and among the plurality of exchange cells, a first unreacted gas passage that circulates to some of the exchange cells and a second unreacted gas that circulates to the remaining exchange cells. A valve that opens and closes the reaction gas passage and the second unreacted gas passage is provided, and by controlling this on-off valve, the humidification amount can be increased, and the humidification amount can be increased even when the humidification amount is insufficient. Thus, it is possible to operate the fuel cell main body in a condition where water is balanced.
[0083]
In the present embodiment, the temperature sensor is used as the detection means, but the same effect can be obtained even if a humidity sensor or a dew point meter is used instead. In addition, the switching to the bypass channel is performed using the switching valve, but the same effect can be obtained by providing an opening / closing valve in one or both of the bypass channel and the already-reacted gas channel.
[0084]
[5. Fifth Embodiment]
This embodiment is a modification of the third embodiment, in which the already-reacted gas flow path is composed of a first already-reacted gas path and a second already-reacted gas path, A water-retaining porous body is disposed between the already-reacted gas flow paths.
[0085]
[5-1. Constitution]
FIG. 19 is a diagram showing the configuration of the fifth embodiment of the polymer electrolyte fuel cell system according to the present invention. That is, in the present embodiment, the already-reacted gas channel 13 is composed of the first already-reacted gas channel 13a and the second already-reacted gas channel 13b, and all the unreacted gas disposed adjacent to each other. A water-retaining porous body 14 is disposed between the gas passage 12 and the first or second already-reacted gas passages 13a and 13b. Other configurations are the same as those of the third embodiment shown in FIG.
[0086]
[5-2. Action / Effect]
FIG. 20 shows an operating state when the on-off valve of the second already-reacted gas channel 13b is closed. In this case, every other reacted gas flows, and the unreacted gas is humidified through the water-retaining porous bodies 14 on both sides thereof. Therefore, one water-retaining porous body is effective for one unreacted gas channel, and humidification is performed.
[0087]
FIG. 19 shows an operating state when the on-off valve of the second already-reacted gas channel 13b is opened. In this case, the already-reacted gas flows through all the previously-reacted gas flow paths, and humidifies the unreacted gas through the water-retaining porous body 14 on both sides thereof. Therefore, two water-retaining porous bodies are effective for one unreacted gas flow path, and humidification is performed, so that the exchange area is doubled and the humidification amount can be increased.
[0088]
Thus, by using the temperature / humidity exchanging means of this embodiment, the amount of humidification can be increased, and the same effect as in the third embodiment can be obtained. In addition, since a water-retaining porous body is arranged on both sides of each flow path, the temperature / humidity exchange means can be made compact, and even when the on-off valve is closed and only the first reaction gas flow path is used, The unreacted gas is humidified to enable stable operation.
[0089]
[6. Sixth Embodiment]
The present embodiment is a modification of the fourth embodiment, and the unreacted gas flow path is composed of a first unreacted gas flow path and a second unreacted gas flow path, A water-retaining porous body is disposed between the already-reacted gas flow paths.
[0090]
[6-1. Constitution]
FIG. 21 is a diagram showing the configuration of the sixth embodiment of the polymer electrolyte fuel cell system according to the present invention. That is, in the present embodiment, the unreacted gas flow path 12 includes the first unreacted gas flow path 12a and the second unreacted gas flow path 12b, and all the first unreacted gas flow paths 12 are arranged adjacent to each other. Alternatively, a water-retaining porous body 14 is disposed between the second unreacted gas channels 12 a and 12 b and the already-reacted gas channel 13. Other configurations are the same as those of the fourth embodiment shown in FIG.
[0091]
[6-2. Action / Effect]
FIG. 22 shows an operating state when the on-off valve of the second unreacted gas flow path 12b is closed. In this case, every other unreacted gas flows and is humidified by the already-reacted gas through the water-retaining porous body 14 on both sides thereof. Therefore, two water-retaining porous bodies are effective for one unreacted gas channel, and humidification is performed.
[0092]
FIG. 21 shows an operating state when the on-off valve of the second unreacted gas flow path 12b is opened. In this case, the unreacted gas flows through all the unreacted gas flow paths, and is humidified by the already-reacted gas through the water-retaining porous bodies 14 on both sides thereof. Therefore, two water-retaining porous bodies are effective for one unreacted gas channel. In this case, compared to when the on-off valve shown in FIG. 22 is closed, the number of water-retaining porous bodies for one unreacted gas channel is the same as two, but flows through one unreacted gas channel. Since the amount of gas is halved, the amount of humidification can be increased.
[0093]
Thus, by using the temperature / humidity exchanging means of this embodiment, the amount of humidification can be increased, and the same effect as in the fourth embodiment can be obtained. In addition, since the water-retaining porous body is disposed on both sides of each flow path, the temperature / humidity exchange means can be made compact, and even when the on-off valve is closed and only the first unreacted gas flow path is used. The unreacted gas is humidified to enable stable operation.
[0094]
[7. Reference example ]
[7-1. Constitution]
As shown in FIG. Reference example The temperature / humidity exchanging means 11 is provided with a temperature adjusting means 80 using an antifreeze liquid. The temperature adjusting means 80 is connected to a line branched at the outlet of the cooling water pump 7 via an on-off valve 81. A pre-reacted gas temperature sensor 82 is provided on the line from the oxidant electrode 2 of the fuel cell to the pre-reacted gas flow path 13 of the temperature / humidity exchange means 11, and the unreacted gas flow of the temperature / humidity exchange means 11 is provided. An unreacted gas temperature sensor 83 is provided on the line from the path 12 to the oxidant electrode 2 of the fuel cell. A control unit 84 is provided for controlling the opening / closing operation of the on-off valve 81 based on the detection results of the already-reacted gas temperature sensor 82 and the unreacted gas temperature sensor 83.
[0095]
[7-2. Action / Effect]
A book having the above configuration Reference example When the temperature / humidity exchanging means 11 needs to be cooled based on the detection results of the already-reacted gas temperature sensor 82 and the unreacted gas temperature sensor 83, the on-off valve 81 is opened and the temperature / humidity exchanging means 11 is opened. The antifreezing liquid is supplied to the temperature adjusting means 80. When the antifreeze is supplied, the temperature / humidity exchanging means 11 is cooled, and the unreacted gas temperature is lowered. Therefore, by controlling the opening / closing of the on-off valve 81 based on the relationship shown in FIG. 2, it is possible to operate in a condition where water in the fuel cell main body is balanced.
[0096]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a high-performance polymer electrolyte fuel cell system capable of appropriately controlling the amount of humidification in the temperature / humidity exchange means.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a first embodiment of a polymer electrolyte fuel cell system of the present invention.
FIG. 2 is a diagram showing a control curve of the fuel cell system according to the first embodiment and the second embodiment.
FIG. 3 is a flowchart showing the operation of the first embodiment.
FIG. 4 is a view showing the configuration of a second embodiment of the polymer electrolyte fuel cell system of the present invention.
FIG. 5 is a flowchart showing the operation of the second embodiment.
FIG. 6 is a diagram showing the configuration of a third embodiment of the polymer electrolyte fuel cell system of the present invention.
FIG. 7 is a longitudinal sectional view showing the configuration of the temperature / humidity exchange means of the third embodiment.
FIG. 8 is a plan view showing the configuration of the first already-reacted gas flow path of the temperature / humidity exchanging means of the third embodiment.
FIG. 9 is a plan view showing the configuration of a second already-reacted gas channel of the temperature / humidity exchanging means of the third embodiment.
FIG. 10 is a plan view showing the configuration of an unreacted gas flow path of the temperature / humidity exchanging means of the third embodiment.
FIG. 11 is a diagram showing a control curve of the fuel cell system according to the third embodiment and the fourth embodiment.
FIG. 12 is a flowchart showing the operation of the third embodiment.
FIG. 13 is a diagram showing the configuration of a fourth embodiment of a polymer electrolyte fuel cell system of the present invention.
FIG. 14 is a longitudinal sectional view showing a configuration of a temperature / humidity exchanging means according to a fourth embodiment.
FIG. 15 is a plan view showing the configuration of the first unreacted gas flow path of the temperature / humidity exchanging means of the fourth embodiment.
FIG. 16 is a plan view showing the configuration of a second unreacted gas channel of the temperature / humidity exchanging means of the fourth embodiment.
FIG. 17 is a plan view showing the configuration of the already-reacted gas flow path of the temperature / humidity exchanging means of the fourth embodiment.
FIG. 18 is a flowchart showing the operation of the fourth embodiment.
FIG. 19 is a longitudinal sectional view showing the structure of the temperature / humidity exchanging means of the fifth embodiment, and shows a state in which the on-off valve of the second already-reacted gas channel is opened.
FIG. 20 is a longitudinal sectional view showing the configuration of the temperature / humidity exchanging means of the fifth embodiment, and shows a state in which the on-off valve of the second already-reacted gas channel is closed;
FIG. 21 is a longitudinal sectional view showing the configuration of the temperature / humidity exchanging means of the sixth embodiment, and shows a state in which the opening / closing valve of the second unreacted gas channel is opened;
FIG. 22 is a longitudinal sectional view showing the configuration of the temperature / humidity exchanging means of the sixth embodiment, and shows a state in which the open / close valve of the second unreacted gas channel is closed;
FIG. 23 shows a polymer electrolyte fuel cell system. Reference example Diagram showing the configuration of
FIG. 24 is a diagram showing a configuration of a conventional polymer electrolyte fuel cell system.

Claims (4)

固体高分子膜を電解質とする固体高分子型燃料電池スタックと、前記燃料電池スタックの反応部を通過した既反応ガスと前記反応部を通過する前の未反応ガスとの熱と水分の交換を行う温湿度交換手段とを有する固体高分子型燃料電池システムにおいて、
前記温湿度交換手段の既反応ガス流路の入口側と出口側を結ぶバイパス通路を形成し、前記バイパス通路への切替弁を設け、
前記反応部を通過した既反応ガスの温度または湿度を検出する第１の検出手段と、前記反応部を通過する前の未反応ガスの温度または湿度を検出する第２の検出手段とを備え、
前記各検出手段によって検出される前記未反応ガス温度と前記既反応ガス温度との比例関係を示す温湿度交換手段のバランス曲線と、生成水が効率良く排出されるために既反応ガス中の水蒸気量が未反応ガス中の水蒸気量と生成水と燃料ガス入口及び出口の水蒸気量の差分との和と等しくなるための前記既反応ガス温度及び前記未反応ガス温度の関係を示す電池水バランス曲線とに基づいて、
前記既反応ガス温度が前記電池水バランス曲線上の既反応ガス温度を下回った場合に前記切替弁を制御して前記バイパス通路へ前記既反応ガスを流し、
その後、前記既反応ガス温度が前記電池水バランス曲線上の既反応ガス温度以上となった場合に前記切替弁を制御して前記バイパス通路を閉じ前記既反応ガス通路へ前記既反応ガスを流すことを特徴とする固体高分子型燃料電池システム。Exchange of heat and moisture between a solid polymer fuel cell stack using a solid polymer membrane as an electrolyte, an already reacted gas that has passed through the reaction part of the fuel cell stack, and an unreacted gas that has not passed through the reaction part In a polymer electrolyte fuel cell system having temperature and humidity exchange means to perform,
Forming a bypass passage connecting the inlet side and the outlet side of the already-reacted gas flow path of the temperature and humidity exchanging means, and providing a switching valve to the bypass passage;
First detection means for detecting the temperature or humidity of the already reacted gas that has passed through the reaction section, and second detection means for detecting the temperature or humidity of the unreacted gas before passing through the reaction section,
The balance curve of the temperature / humidity exchange means showing the proportional relationship between the unreacted gas temperature detected by the detection means and the already-reacted gas temperature, and the water vapor in the already-reacted gas in order to efficiently discharge the generated water The battery water balance curve showing the relationship between the existing reaction gas temperature and the unreacted gas temperature so that the amount is equal to the sum of the amount of water vapor in the unreacted gas and the difference between the generated water and the difference in water vapor amount at the fuel gas inlet and outlet And based on
When the already-reacted gas temperature falls below the already-reacted gas temperature on the battery water balance curve, the switch valve is controlled to flow the already-reacted gas to the bypass passage,
Thereafter, when the already-reacted gas temperature becomes equal to or higher than the already-reacted gas temperature on the battery water balance curve, the switch valve is controlled to close the bypass passage and to flow the already-reacted gas to the already-reacted gas passage. A polymer electrolyte fuel cell system. 固体高分子膜を電解質とする固体高分子型燃料電池スタックと、前記燃料電池スタックの反応部を通過した既反応ガスと前記反応部を通過する前の未反応ガスとの熱と水分の交換を行う温湿度交換手段を有する固体高分子型燃料電池システムにおいて、
前記温湿度交換手段の未反応ガス流路の入口側と出口側を結ぶバイパス通路を形成し、前記バイパス通路への切替弁を設け、
前記反応部を通過した既反応ガスの温度または湿度を検出する第１の検出手段と、前記反応部を通過する前の未反応ガスの温度または湿度を検出する第２の検出手段とを備え、
前記各検出手段によって検出される前記未反応ガス温度と前記既反応ガス温度との比例関係を示す温湿度交換手段のバランス曲線と、生成水が効率良く排出されるために既反応ガス中の水蒸気量が未反応ガス中の水蒸気量と生成水と燃料ガス入口及び出口の水蒸気量の差分との和と等しくなるための前記既反応ガス温度及び前記未反応ガス温度の関係を示す電池水バランス曲線とに基づいて、
前記既反応ガス温度が前記電池水バランス曲線上の既反応ガス温度を下回った場合に前記切替弁を制御して前記バイパス通路へ前記未反応ガスを流し、
その後、前記既反応ガス温度が前記電池水バランス曲線上の既反応ガス温度以上となった場合に前記切替弁を制御して前記バイパス通路を閉じ前記未反応ガス通路へ前記未反応反応ガスを流すことを特徴とする固体高分子型燃料電池システム。Exchange of heat and moisture between a solid polymer fuel cell stack using a solid polymer membrane as an electrolyte, an already reacted gas that has passed through the reaction part of the fuel cell stack, and an unreacted gas that has not passed through the reaction part In a polymer electrolyte fuel cell system having temperature / humidity exchange means to perform,
Forming a bypass passage connecting the inlet side and the outlet side of the unreacted gas flow path of the temperature and humidity exchange means, and providing a switching valve to the bypass passage;
First detection means for detecting the temperature or humidity of the already reacted gas that has passed through the reaction section, and second detection means for detecting the temperature or humidity of the unreacted gas before passing through the reaction section,
The balance curve of the temperature / humidity exchange means showing the proportional relationship between the unreacted gas temperature detected by the detection means and the already-reacted gas temperature, and the water vapor in the already-reacted gas in order to efficiently discharge the generated water The battery water balance curve showing the relationship between the existing reaction gas temperature and the unreacted gas temperature so that the amount is equal to the sum of the amount of water vapor in the unreacted gas and the difference between the generated water and the difference in water vapor amount at the fuel gas inlet and outlet And based on
When the already-reacted gas temperature is lower than the already-reacted gas temperature on the battery water balance curve, the unreacted gas is caused to flow to the bypass passage by controlling the switching valve,
Thereafter, when the already-reacted gas temperature becomes equal to or higher than the already-reacted gas temperature on the battery water balance curve, the switching valve is controlled to close the bypass passage and allow the unreacted reaction gas to flow into the unreacted gas passage. A polymer electrolyte fuel cell system. 前記温湿度交換手段が、複数の交換セルから構成され、前記複数の交換セルのうち、一部の交換セルに流通する第１の既反応ガス流路と、残りの交換セルに流通する第２の既反応ガス流路とが設けられ、前記第２の既反応ガス流路を開閉する開閉弁が設けられ、
前記温湿度交換手段のバランス曲線と、前記電池水バランス曲線とに基づいて、
前記既反応ガス温度が前記電池水バランス曲線上の既反応ガス温度を上回った場合に前記開閉弁を開いて前記第２の既反応ガス流路へ前記既反応ガスを流し、
その後、前記既反応ガス温度が前記電池水バランス曲線上の既反応ガス温度以下となった場合に前記開閉弁を閉じて前記第１の既反応ガス流路のみへ前記既反応ガスを流すことを特徴とする請求項１に記載の固体高分子型燃料電池システム。The temperature / humidity exchange means is composed of a plurality of exchange cells, and among the plurality of exchange cells, a first already-reacted gas flow path that circulates to a part of the exchange cells and a second that circulates to the remaining exchange cells. And an open / close valve that opens and closes the second pre-reacted gas flow path,
Based on the balance curve of the temperature and humidity exchange means and the battery water balance curve,
When the already-reacted gas temperature exceeds the already-reacted gas temperature on the battery water balance curve, the on-off valve is opened to flow the already-reacted gas to the second already-reacted gas channel,
Thereafter, when the already-reacted gas temperature becomes equal to or lower than the already-reacted gas temperature on the battery water balance curve, the on-off valve is closed and the already-reacted gas is allowed to flow only to the first already-reacted gas channel. 2. The polymer electrolyte fuel cell system according to claim 1, wherein 前記温湿度交換手段が、複数の交換セルから構成され、前記複数の交換セルのうち、一部の交換セルに流通する第１の未反応ガス流路と、残りの交換セルに流通する第２の未反応ガス流路とが設けられ、前記第２の未反応ガス流路を開閉する開閉弁が設けられ、
前記温湿度交換手段のバランス曲線と、前記電池水バランス曲線とに基づいて、
前記既反応ガス温度が前記電池水バランス曲線上の既反応ガス温度を上回った場合に前記開閉弁を開いて前記第２の未反応ガス流路へ前記未反応ガスを流し、
その後、前記既反応ガス温度が前記電池水バランス曲線上の既反応ガス温度以下となった場合に前記開閉弁を閉じて前記第１の未反応ガス流路のみへ前記未反応ガスを流すことを特徴とする請求項２に記載の固体高分子型燃料電池システム。The temperature / humidity exchange means is composed of a plurality of exchange cells, and among the plurality of exchange cells, a first unreacted gas flow path that circulates to some of the exchange cells and a second that circulates to the remaining exchange cells. An unreacted gas flow path, and an open / close valve for opening and closing the second unreacted gas flow path,
Based on the balance curve of the temperature and humidity exchange means and the battery water balance curve,
When the already-reacted gas temperature exceeds the already-reacted gas temperature on the battery water balance curve, the on-off valve is opened to flow the unreacted gas to the second unreacted gas flow path,
After that, when the already-reacted gas temperature becomes equal to or lower than the already-reacted gas temperature on the battery water balance curve, the on-off valve is closed to flow the unreacted gas only to the first unreacted gas channel. 3. The polymer electrolyte fuel cell system according to claim 2, wherein
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