Analysis of water and thermal management with coolant operating conditions for a proton exchange membrane fuel cell

A coolant operating condition in a fuel cell stack is an important factor to determine the temperature distribution which affects a fuel cell performance and relative humidity at its inside. In this study, the effect of the coolant operating condition on the performance of the fuel cell stack was investigated with relative humidity at the H2 inlet. For relative humidity values at the H2 inlet of 0%, 50% and 100%, tests were conducted with the coolant flow rate of 0.1–0.8 l/min cell and the coolant inlet temperature of 20–82 °C. The coolant inlet temperature had a proper range to maintain the optimal cell voltage. The proper range of coolant inlet temperature increased with increasing the coolant flow rate and relative humidity at the H2 inlet. When considering the optimal voltage efficiency, the relative humidity at the H2 inlet of 50% was comparatively the optimum condition. Then the heat removal rate was 0.40–0.65 W/cm2 cell.