Sensitivity Analysis of the Impedance Characteristics of Proton Exchange Membrane Fuel Cells

The sensitivity of the impedance characteristics to the operating conditions of the proton exchange membrane fuel cell is studied. The impedance of a cell is measured in different potentials (current densities), operating temperatures, and anode and cathode relative humidities to estimate the indifference interval of each of these parameters. The indifference interval of a parameter, defined for a specific point, refers to a range out of which the impedance results are statistically dissimilar from that specific point. The analysis presented evaluates the average indifference intervals of the potential, temperature and relative humidities to be 10 mV, 5 degrees C and 7%, respectively. In other words, the changes less than the above mentioned limits do not affect the impedance of the cell statistically.