Adaptation of F-EIS for Online PEMFC Analysis

摘要

An adaptation of the fast impedance spectroscopy (F-EIS) allows integrating the impedance spectroscopy into fuel cell systems for online analysis. The cost intensive installation of frequency response analyzers for laboratory research can be replaced by a low cost F-EIS-hardware tailored for the specific reduced functional range in PEMFC systems. The focus lies on the adaptation of the F-EIS perturbation signal. Two parameters are of special interest -the amplitude and the frequency. One aim is to keep the perturbation input as small as possible to neglect the effect of system non-linearity and to avoid negative effects on the load. However, the biggest possible effect from the perturbation signal has to be achieved, to create significant cell responses which are less sensitive to noises and instabilities and will lead to reliable results. For the frequency the upper limit is defined by sample rate and the lower limit by the measurement time. For a fast online analysis the measurement period should be reduced and the sample rate increased as far as necessary to still retrieve the important information from the impedance data.