Spatial and Temporal Behavior in Proton Exchange Membrane Fuel Cells

University Of Kansas Center For Research Inc, Lawrence KS

Investigators

Abstract

Abstract - Nguyen - 9910923 The proton exchange membrane (PEM) fuel cell system is a possible replacement for the internal combustion engine in vehicles if its performance and efficiency is improved. Of the performance controlling components in the PEM fuel cell, the membrane and the cathode are the two most influential components. The conductivity of the membrane, which is directly proportional to its hydration state, determines how much current can be passed through the cell. The oxygen reduction rate at the cathode is the limiting step and determines how much current can be generated. During operation, the effect of proton migration causes water molecules to move from the anode to the cathode resulting in membrane dehydration at the anode side and electrode flooding at the cathode. The membrane dehydration and electrode flooding problems are localized, resulting in nonuniform current distribution and result in localized hot spots and stress on the membrane that could lead to cell failure. A segmented PEM fuel cell will be built to detect and identify operating conditions and variables that control the current distribution and the root causes of spatiotemporal current density behavior. The cell will be used to identify operating conditions, electrode characteristics and flow field designs that lead to nonuniform current distribution and the general spatiotemporal behavior of PEM fuel cells. The results will be used to determine optimal operating conditions and to develop electrode and flow field designs that will result in higher efficiency and performance PEM fuel cells.