Sensitivity analysis of anode overpotential during start-up process of a high temperature proton exchange membrane fuel cell

This paper investigates the sensitivity of start-up parameters during the start-up or warm-up process of a high temperature proton exchange membrane fuel cell (HT-PEMFC), where carbon monoxide (CO) contaminated hydrogen is used as fuel. The heating strategy considered in this study involves external heating of the HT-PEMFC to an initial start-up temperature (above 100 degrees C), after which current is extracted, where the external heating still remains. A transient three-dimensional isothermal anode model is developed to determine the sensitivity of operational start-up parameters such as temperature increase rate, initial start-up temperature, CO volume fraction and extracted current density, on the anode overpotential during the start-up process. The results indicate that having a low initial start-up temperature is the key reason that makes the other parameters such as the current density, CO mole fraction and temperature increase rate, sensitive, especially at 108 degrees C. In addition, temperature range of 130 +/- 5 degrees C is most critical as the sensitivity reaches a peak for all parameters at the three considered initial start-up temperatures. In addition, a system-level energy analysis considered for the start-up process of a 1-kW stack, suggests that having low initial start-up temperature can reduce warm-up time and energy consumption. (C) 2015 Elsevier Ltd. All rights reserved.