Analysis of the Local Dependency vs. Time in a Fuel Cell Stack after Process Parameter Transients by Means of Multi-Channel Synchronous Impedance Measurements

Kurzfassung

Impedance spectra were successfully acquired synchronously in parallel on all cells of a 5-cell short SOFC stack. The SOFC response speed on humidity changes was fast compared with the timescale of Impedance Spectroscopy. Relevant kinetic findings through EIS, in particular effective gas diffusion lengths require well controlled process parameters including a definite fuel gas humidity. Relevant findings about membrane, inter-connector and contact resistance losses through EIS require a careful electrical set-up, in particular avoiding mutual induction.