Online Estimation of Membrane Water Content in Vehicular PEMFC by Complex Morlet Wavelet Transformations
The amount of water content in membrane electrode assembly (MEA) is an important factor affecting the efficiency and life of proton exchange membrane fuel cell (PEMFC), and there are several methods to measure it. However, it’s widely believed that the most feasible method to measure the water content in the MEA is an indirect way as described below: measure the electrochemical impedance spectroscopy (EIS), and take advantage of the positive correlation between the proton’s conductivity, which is reciprocal of specific resistance, and the water content in MEA. The traditional EIS measurement method has the shortcoming of high cost and slow speed, especially in low frequency bands, so this method is unsuitable for high-power vehicle fuel cell systems. In this paper, a measuring method which does not require a large number of experiments and only need to perform Morlet wavelet transform on the PEMFC voltage signal as well as current signal is proposed.