Through-Plane Water Transport Visualization in an Operating PEM Fuel Cell by Visible and Infrared Imaging

In this study, the liquid water emergence and transport within anode and cathode gas diffusion layers in an operating fuel cell was observed from the cross-section with a digital microscope and a high resolution infrared camera. In the cathode, water droplets were found to be formed on the channel side of the GDL cross-section, while little water was detected in the vicinity of the microporous layer. This finding suggested that water was condensing inside the GDL and may imply the existence of a condensation front, which has been predicted by numerical simulation but previously has not been verified experimentally. The anode results indicate that water was transported through anode GDL dominantly in the vapor form. The temperature distributions across the anode and cathode GDL were also measured with a high resolution infrared camera. These visualizations provided critical information on the water transport across a fuel cell.