Parametric study on the local current distribution of polymer electrolyte membrane fuel cell with counter flow channel under pressurized condition

Abstract

Local measurement of current was conducted using a segmented cell to understand local electrochemical characteristics of polymer electrolyte membrane fuel cell with counter flow channel under pressurized condition. We changed stoichiometry ratio (SR), relative humidity (RH), and operating temperature to examine the effect of operating parameters on the performance of fuel cell under pressurized condition. A segmented fuel cell with a divided active area of 25 cm2 was used to measure local current distribution to analyze complex relationships between SR, RH, temperature and pressure. The results show that RH and SR are the main factors for determining current distribution. High SR with low-RH reactants make the membrane of the inlet region more dried out, which leads to less electrochemical reaction. When SR is low, however, less water is evaporated and the effect of RH condition is minimized. On the other hand, current distribution at various RH and SR conditions at 3 bar is relatively similar among the results. Thus, the effects of RH and SR can be neglected for high operating pressure cases. When the temperature is high in pressurized condition, the Ohmic loss decreased and the overall cell performance improved.