Measurement of Liquid Water Accumulation in a Proton Exchange Membrane Fuel Cell with Dead-ended Anode

The operation and accumulation of liquid water within the cell structure of a polymer electrolyte membrane fuel cell (PEMFC) with a dead-ended anode is observed using neutron imaging. The measurements are performed on a single cell with 53 square centimeter active area, Nafion 111-IP membrane and carbon cloth Gas Diffusion Layer (GDL). Even though dry hydrogen is supplied to the anode via pressure regulation, accumulation of liquid water in the anode gas distribution channels was observed for all current densities up to 566 mA cm−2 and 100% cathode humidification. The accumulation of liquid water in the anode channels is followed by a significant voltage drop even if there is no buildup of water in the cathode channels. Anode purges and cathode surges are also used as a diagnostic tool for differentiating between anode and cathode water flooding. The rate of accumulation of anode liquid water, and its impact on the rate of cell voltage drop is shown for a range of temperature, current density, cathode relative humidity and air stoichiometric conditions. Neutron imaging of the water while operating the fuel cell under dead-ended anode conditions offers the opportunity to observe water dynamics and measured cell voltage during large and repeatable transients.