Real-Time Species Distribution Profiling in PEFCs

Knowledge of the species, current, and high frequency resistance distributions within a polymer electrolyte fuel cell (PEFC) is critical to enable prediction of the local performance and accurately quantify various species transport parameters. In micro and portable fuel cell systems, precise knowledge of steady state and dynamic water transport is especially important. This paper examines the distributed prifile of water vapor and other gas phase species in a PEFC, using a novel real-time technique for in situ species distribution measurement within the reactant flow channels of an operating PEFC. This is accomplished with an Agilent Real-Time Gas Analyzer (RTGA) that enables continuous profiling of changing species mole fractions at many locations along the anode and cathode flow paths, and enables detailed understanding of the time scales of the various multi-phase dynamic transport phenomena. Additionally, the periodic presence of liquid water droplets in the cathode can be observed at high current density with this technique.