Overall and local effects of operating conditions in PEM fuel cells with dead-ended anode

Abstract

Nitrogen and water accumulations in fuel cells with dead-ended anode can cause severe cell performance decline and fluctuations. In this work, both overall and local effects of fuel cell operating parameters, i.e., cathode humidity, air stoichiometry, hydrogen pressure and operating current density, have been experimentally studied under galvanostatic mode. A purge at the anode is automatically triggered when the cell voltage has decreased by 0.1 V and the mean purge interval, defined as the average time between two purges, is recorded as a characteristic parameter. Local current densities are measured to study the local effects and detailed local characteristics of the fuel cell. The experimental results show that mean purge intervals decrease with cathode inlet humidity and operating current density, and increase with inlet hydrogen pressure and air stoichiometry. The experimental results also show that the local current densities change very differently at different locations and impurities first accumulate near the end of the anode channel and then gradually progress upstream.