Air flow and pressure optimization for air supply in proton exchange membrane fuel cell system

Abstract

To study the air supply of proton exchange fuel cell (PEMFC) system to avoid air starvation, a proton PEMFC system model mainly including the stack (30 kW, 240 cells, 190 cm2 activation area) and air supply system is developed. Model's average relative errors of output mass flow and pressure are 2.9% and 0.756% respectively. Model' saverage relative error of output voltage is 2.678%. Subsequently, the influence of operating parameters (air excess ratio and air pressure) on output performance (dynamic response of stack voltage and on net output power of PEMFC system) is analyzed. When air excess ratio is 4 and pressure is 1.7 bar respectively, voltage's dynamic response reaches the best level. Optimal pressure to output maximum net power is always located in lower value region and optimal flow shows a tendency to be gradually larger as current increases. Then the optimization model to determine working points of each parameter aiming at comprehensively improve voltage's dynamic response and net output power of PEMFC system simultaneously is presented. Based on this, an optimized air supply strategy of replenishing air upon loading is innovatively proposed. This research can be further used to guide the development of control strategy of air supply.