Mathematical modeling and performance analysis of proton exchange membrane fuel cell

Polymer Electrolyte Membrane (PEM) fuel cells have received increasing attention because they are widely regarded as a potential future stationary and mobile power sources. In this paper, one-dimensional, steady state model for PEM fuel cell stack is developed in MATLAB environment and the effect of various overpotentials on the polarization and the efficiency of fuel cell are studied. At low current draw, there is a sudden increase in activation overpotential due to the slow electron transfer rate and a portion of the electrode voltage is lost to compensate for the lack of electro-catalytic activity. At all current draw, ohmic losses are linear with current density due to the low conductivity of membrane. At higher current draw, the electrochemical reactions are hindered by the water generated at the cathode and voltage drops. Efficiency drops with increasing power density; hence there is a trade-off between high power and high efficiency. Fuel cell system designers must select the desired operating range according to whether efficiency or power is paramount for the given application.