Exploring liquid water distribution and local heating effects in an operating proton exchange membrane fuel cell

Neutron radiography experiments were performed on an operating proton exchange membrane fuel cell at the NIST Center for Neutron Research. The NIST Neutron Imaging Facility at BT-2 enables liquid water in standard fuel cell test hardware to be imaged with resolution of approximately 130 microns using an amorphous silicon flat panel detector. The majority of the experiments in this work were performed with the cell plane oriented normal to the beam to measure the "face-on" area distribution of liquid water across the 50 cm ² surface of the cell. Effects of current density and temperature on the distribution and quantity of water were quantified for a range of conditions. A select number of experiments were performed with the cell face oriented parallel with the beam to image the water content profile of the operating fuel cell. These few experiments were performed to confirm that most of the effects observed were dominated by changes in the cathode water content.