Visualization of water transport in GDL and flow channel of PEMFC

Abstract

AbstractLiquid water penetrating the gas diffusion layer (GDL) of a proton exchange membrane fuel cell (PEMFC) was studied. The gas diffuse layer (GDL) has a great impact on PEMFC's performanc3e, and is an important component of a PEMFC. An ex‐situ test was conducted on a transparent test cell to visualize the water droplet formation and detachment on the surface of different types of GDLs through a CCD camera. The breakthrough pressure, at which the liquid water penetrates the GDL and starts to form a droplet, was measured. The breakthrough pressure was found to be different for GDLs with different porosities and thicknesses. The equilibrium pressure, which is defined as the minimum pressure required for maintaining a constant flow through the GDL, was also recorded. The equilibrium pressure was found to be much lower than the breakthrough pressure for the same type of GDL. Also the drain performance using three kinds of different bipolar plates were compared in this paper. According to the result of experiment, the average diameters of porous GDLs were found determining the penetrating pressure. Serpentine flow channel proved the best pattern for drainage. © 2011 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/htj.20330