Electrochemical Pressure Impedance Spectroscopy As a Diagnostic Method for Hydrogen-Air Polymer Electrolyte Fuel Cells

摘要

Water transport in an operating hydrogen-air fuel cells has gathered the interests of both researchers and developers working on fuel cells. Better water removal can extend the operation regime of fuel cells and, therefore, increase its maximum cell power and overall energy efficiency. However, state-of-art in situ fuel cell diagnostics cannot provide an insight into the water transport phenomenon. Recent research shows that pressure controlling techniques have the potential to address issues with water transport. The purpose of this work is to develop an in-situ diagnostic tool from cathode pressure oscillations for hydrogen-air polymer electrolyte fuel cells named as electrochemical pressure impedance spectroscopy (EPIS). The response between the cell voltage and the pressure oscillations is analogous to the electrochemical impedance spectroscopy (EIS)(See image). The relation between EPIS response and water transport phenomenon is intensively studied in this work. With the help from our industrial partner, Greenlight Innovation Corp., we are able to integrate this diagnostic method into a fuel cell test station. Experimental data are fitted by the mathematical derivation of the response from theoretical cell components from which are extracted crucial parameters and diagnostic information for water transport.