Simplified Model to Predict Incipient Flooding/Dehydration in Proton Exchange Membrane Fuel Cells

Abstract

Proper water management is critical for near-ambient temperature operation of a fuel cell. A simplified water balance model has been developed to predict when incipient flooding/dehydration may take place. The present model is based on multicomponent diffusion in the electrodes and molar balance in the flow channels. The overall model is in the form of a closed-form expression for the critical or threshold or balance current density at which the water production rate and the water vapor evacuation rate are exactly balanced. The model incorporates the influence of the operating conditions, properties of electrodes, and flow and geometric parameters in the gas channels on the balance current density. Predictions from the model of the state—incipient flooding or dehydration—of operation of the fuel cell agree well with the available experimental data. Using the model, a parametric study has been conducted over a range of parameters.