固体高分子形燃料電池のアノードガス再循環がカソード無加湿運転時の発電性能に及ぼす影響(熱工学,内燃機関,動力など)  [in Japanese] Influence of Anode Gas Recirculation on the PEFC Performance under No-Humidification at the Cathode(Thermal Engineering)  [in Japanese]

Polymer electrolyte fuel cells (PEFCs) generally have external humidifiers to supply humidified hydrogen and oxidant gases. If a PEFC could be operated under very low humidity condition, external humidifiers may be removed, resulting in a very simplified PEFC system with increased total efficiency and reduced cost. The present study was carried out to clarify the influence of anode gas recirculation on the PEFC performance under no-humidification at the cathode. Increasing the flow rate of anode gas recirculation is effective to improve water transport from the anode gas to the membrane electrode assembly (MEA), enhancing the PEFC performance. Increasing humidity of the anode supplied gas is also effective to enhance the PEFC performance without an increase in concentration overpotential caused by flooding at high current densities. For the cathode GDL, it is important to maintain humidity and prevent drying-out of the MEA. A microporous layer (MPL) coated GDL is effective for enhancing the PEFC performance. For the anode GDL, it is important to increase water transport from the humidified anode gas to the MEA. The anode GDL without the MPL is effective for enhancing the PEFC performance.