パラレルハイブリッド形流路を有するPEFCの開発研究:　第1報，流路の設計と基本特性

摘要

内燃機関に代わる自動車用の動力源としてエネルギーrn変換効率が高い固体高分子形燃料電池（以下PEFC）が注目rnされている．水素を燃料としたPEFCは水しか排出しないrnゼロエミッション動力源でもある．rnPEFCの性能向上には電極部に反応ガスを十分に供rn給し，生成水を速やかに排出することが必要であり，rnこれらを効率的に行えるガス流路の設計が重要である．rn現在のガス流路設計の多くは，拡散層に沿って流れるrnガス流から電極に反応ガスを供給し，電極から排出さrnれる生成水をガス流によって外部に排出する方式であrnり，パラレル形とサーペンタイン形，およびこれらのrn改良形が一般的である．%We have developed hybrid gas channels for polymer electrolyte fuel cells (PEFCs) that can arbitrarily change the ratio of the flow rates between interdigitated and parallel flows. We study gas channel structure and the above ratio by analyzing overpotentials to improve the cell performance. The flow rates of the two flows are controlled by valves of the inlets and outlets of high and low pressure gas channels in the cathode. The flow coefficients of the valves (CV values) are measured beforehand for calibration. Differences between total flow rate and each the flow rate give the rate of in-plane flow passing through the GDL under the rib of the separator. Increasing the flow rate through the GDL under the rib of the cathode separator improves the cell performance although the effect of the flow rates in the high and low pressure gas channels of the cathode on the cell performance is small. This can be explained by that large amount of oxygen is consumed at the electrode (catalyst layer) under the rib where the electrode reaction takes place predominantly.