Dependency of the Power of the Constant Phase Element to Operating Conditions in Proton Exchange Membrane Fuel Cells

Despite the numerous studies conducted on the constant phase element (CPE) characteristics, they are not fully understood yet. In this paper, the constant phase element required for modeling the impedance characteristics of the proton exchange membrane fuel cells are studied in different operating conditions. The impedance of the cell is measured in different temperatures, anode and cathode relative humidities and potentials (current densities). Then, the powers of the constant phase elements required for modeling the most dominant arc in the measured Nyquist plots are determined, and the values are compared in different operating conditions using the analysis of variance method. It is shown that the CPE power is not related to the temperature and relative humidities; while it changes slightly when the potential or current density changes.