Dynamic Analysis and Diagnostics of a High Temperature PEM Fuel Cell Stack

Abstract

In this work, impedance measurement was performed on a high temperature PEM fuel cell stack module consisting of 65 planar single cells. Pure hydrogen and ambient air were supplied into the stack. The impedance data of the stack were collected under varying loads at 160ºC. However, temperature variations and gradient existed over the whole stack during the measurement. The impedance measurement was then repeated under the same operating conditions to collect the second set of data. An unexpected increase of cell impedance was observed. An EC diagram was derived to simulate the impedance data of the stack module. The electronic auxiliaries and temperature profiles of the stack module were analyzed to study their effects on stack impedance.