Performance Optimization for Open‐cathode Fuel Cell Systems with Overheating Protection and Air Starvation Prevention

The open-cathode design with simultaneously integrated air supply and coolant flow systems can significantly simplify the structure of proton exchange membrane fuel cell (PEMFC). Typically, the performance of open-cathode PEMFC system is highly influenced by temperature and oxygen excess ratio which can be regulated by the air flow fan. The axial air flow fan is the only actuator which is responsible for the oxygen supply to the cathode and cooling air at the same time. In this study, oxygen mass flow rate across cathode channels is regarded as the only control variable of the open-cathode FC system. Air flow is regulated based on a set of optimal oxygen excess ratios in different stack currents for power optimization and overheating protection. However, the air flow rate is determined through a sensor installed to measure the air flow rate in the cathode channels. The control strategy simultaneously focuses on performance optimization with overheating protection and air starvation prevention, whereas the fuel cell operates its full range. The efficacy of the proposed method and control is verified through experiments with a small open-cathode fuel cell system with a real-time platform of NI (National Instruments) devices.