Visualization and Measurement of Dynamic Water Behavior in Polymer Electrolyte Fuel Cell by Neutron Radiography

Abstract

Visualization of water behavior in a polymer electrolyte fuel cell was conducted by neutron radiography. Real-time video images and high-resolution still images were photographed with measurement of fuel cell performance. It was clearly visualized by real time imaging that water condensed in an air supply line was coming into a fuel cell. In this case the cell voltage decreased when water flowed into the cathode side. On the other hand, no effect of condensed water into the anode side was observed on the cell performance. In the high resolution still imaging, water amount was measured quantitatively. The water thickness was evaluated for the gas diffusion layer (GDL) covered by ribs and channel part with GDL separately. It was shown that the higher oxygen utilization, i.e. lower air flow rate, caused an increase of water amount and lowering of cell voltage. It can be said that water amount in the PEFC might strongly depend on airflow rate, and the cell voltage might be affected by the water amount.