Impedance-based diagnosis of polymer electrolyte membrane fuel cell failures associated with a low frequency ripple current

This work deals with a diagnosis of cathode flooding and membrane drying associated with a low frequency ripple current of a polymer electrolyte membrane fuel cell (PEMFC) based on impedance measurement on 12 single cells using electrochemical impedance spectroscopy (EIS). Average values of the identified model parameters obtained from direct measurement of the impedance curves of 12 single cells obtained after cycling for hours at variable frequencies, it has been found that impedance magnitude of a fuel cell injecting a low frequency ripple current (100 Hz) increased when compared with those injecting high frequency ripple currents (1 kHz and 10 kHz). Based on these investigations, additional impedance measurements are directly conducted to gain insight into cathode flooding and membrane drying concerning a low frequency ripple current. Regardless of operating frequency of ripple current, two PEMFC failures lead to an increase in the impedance magnitude in comparison with that of a fresh cell. Specifically, it is shown that a low frequency ripple current more accelerates the PEMFC degradation associated with two PEMFC failures.