Direct Liquid Water Hydration of Fuel Cell Membranes

Abstract

Direct liquid water hydration of polymer electrolyte fuel cell membranes improves cell performance and has system advantages over conventional reactant humidification schemes. The liquid hydration of the membrane is accomplished in our case by wicking water from a supply in the anode flow-field through the otherwise hydrophobic anode gas diffusion backing directly to the membrane/electrode assembly. The liquid water can be provided to the anode plenum either by injecting droplets into the hydrogen cell inlet or by integrating water channels into the anode flow-field. Conventional carbon-cloth gas diffusion backings are modified to provide the anode wicking backing by sewing in fine multifilament wicking threads using a conventional sewing machine. This simple scheme is demonstrated to provide improved performance and good stability.