Performance Improvement for Electrode Flooding with Novel Gas Diffusion Layer Less Polymer Electrolyte Membrane Fuel Cells

首都大学東京博士(工学)The gas diffusion layer (GDL)-less fuel cell that is composed of a corrugated-mesh shows less flooding performance even in the high current density region, because gases are supplied more uniformly to the catalyst layer in comparison with the conventional fuel cell utilizing GDL. On the other hand, its internal electrical resistance is higher than that of conventional fuel cell, because corrugate mesh and underneath microporous layer (MPL) makes less contact area with points-contact. This can increase the resistance at the interface between corrugated-mesh and MPL as well as MPL and catalyst layer (CL) greatly from the conventional fuel cell where GDL can make good contact with MPL. In this study the conductivities and contact resistances of each material are measured under various mechanical compression pressures, and coupled mechanical-electric-electrochemical simulation is developed to investigate the effect of these electrical resistance. As a result, it is found that our model can simulate well for the GDL-less fuel cell and the effect of the electric resistance in the GDL-less fuel cell has a big contribution on the polarization performance.固体高分子形燃料電池は次世代の自動車用動力源として期待されるが，その本格的利用のためには発電出力密度の更なる向上が求められる．燃料電池の発電出力向上のためには，反応物供給の均一化，内部抵抗の低減，触媒活性の向上などが求められるが，とくに高電流密度条件においては，発電と同時に生成する水が反応物流路を閉塞して反応物の均一な供給を妨げるフラッディングと呼ばれる現象が問題となる．このため，フラッディングの問題の解決は固体高分子形燃料電池の発電出力密度を向上させる上で極めて重要な課題である．以上の背景から，本研究では，金属製のマイクロコイルおよびコルゲートメッシュを用いた新たな構造の反応物流路を提案し，これらの流路を固体高分子形燃料電池に用いることによる発電性能向上を試みた．その際，とくに耐フラッディング性の向上および内部抵抗の低減に着目した検討を行い，流路構造がそれらに与える影響について解析を行った．doctoral thesi