Characterisation of PEM fuel cell cold start process

Water droplets formed in PEM fuel cell operating conditions freeze at sub-zero temperatures and cause start-up failure. In this thesis, a quick, effective, and low energy-consuming coolant heating method has been developed by characterizing the cold start process of the PEM fuel cell. The effects of the components in the experimental setup on the cold start performance were investigated in the range of -10 and -30 ℃. The fuel cell and the external heating system were operated simultaneously and a current was drawn from the cell during the tests. Stack temperature was followed from five different symmetrical places and temperature-voltage-current profiles were plotted. In the preliminary tests at -10 ℃, ethanol as the working fluid, double-sided heating type, and full power pump operation were specified as the parameters that provide the quickest heating. The effect of the heater and pump operating durations under the same energy consumption level were compared and no significant difference was noted at this temperature. However, it is found that long pump operation at extreme conditions (-15 and -30℃ range) is essential for a successful cold start process and it provides a more homogeneous and smooth temperature transition. PEM fuel cell was operated successfully in all conditions thanks to the external heating mechanism, and the cell temperature was increased above zero in 20, 40, and 53 seconds, respectively, in cold start tests at -10, -20, and 30 ℃. Keywords: PEM fuel cell, cold start, assisted, starter technique, experimental