Water Transport through a Proton-Exchange Membrane (PEM) Fuel Cell Operating near Ambient Conditions: Experimental and Modeling Studies

Abstract

In the present work, an experimental study on the performance of an “in-house”-developed proton-exchange membrane (PEM) fuel cell with 25 cm2 of active membrane area is described. The membrane/electrodes assembly (MEA), from Paxitech, has seven layers [membrane/catalyst layers/gas diffusion layers (GDLs)/gaskets]. The catalytic layers have a load of 70% Pt/C and 0.5 mg of Pt/cm2 on both sides, and the membrane is made of Nafion 112. A multiserpentine configuration for the anode and cathode flow channels is used. Experiments were carried out under different anode and cathode relative humidities (RHs) and flow rates. Predictions from a previously developed one-dimensional model, coupling mass- and heat-transfer effects, are compared to experimental polarization curves. The influence of the anode and cathode relative humidification level on the cell performance is explained under the light of the predicted water content across the membrane. Under the operating conditions studied, the net water flux of water is toward the anode. Accordingly, the influence of the anode humidification is not significant, and the influence of the cathode humidification has a high impact in fuel cell performance. Results show that fuel cell performance is better for experiments where higher water content values were obtained. In comparison to the anode feed flow rate influence, the influence of the cathode feed flow rate has a major impact in fuel cell performance.