無水高温型PEFCにおける始動および高温発電性能改善に向けた流路構造

抄録

Polymer Electrolyte Fuel Cell (PEFC) has high energy conversion efficiency because it can directly convert chemical energy into electrical energy, and discharges only water during the power generation, which reduces the environmental impact. Fuel Cell Vehicles (FCVs) are being developed and deployed in commercial vehicles, such as large trucks and buses, to further popularize them in the future. To improve power generation efficiency and reduce the load on the cooling system, it is necessary to increase the operating temperature (aiming for up to 180°C). One of main advantages of the higher operating temperatures compared to conventional PEFC is the larger temperature difference from the ambient temperature, which improves cooling capacity and allows for higher load operation. In this study, we conducted experimental investigations and improvements on the flow field structure of non-humidification high-temperature PEFC. The objective is to reduce concentration overvoltage at high temperature operations and to actively discharge water generated during startup from low temperatures. In the experiment, three types of flow field were used. The pressure and temperature dependence of IV characteristics under high temperature conditions and the oxygen transport resistance at low temperature were investigated. The results showed that an interdigitated flow field has excellent high-temperature IV characteristics, where a 0.5mm straight flow field was the most suitable for discharging generated water at the low temperature.