Analysis of Fuel Cell Stacks Degradation by Polarization Change Curves

Polarization change curves, defined as a difference between polarization curve at the beginning of life and at the end of life (or at the end of the experiment) were used to analyze degradation of a couple of fuel cell stacks. The first stack after 1600 hours of operation exhibited significant increase in activation losses and total resistance, as well as increase in hydrogen crossover. The improved stack during 5000 hours of operation exhibited almost no increase in activation losses and no increase in hydrogen crossover. The cell resistance increased but at a half the rate of the first stack. By the analysis of the polarization change curves it was possible to identify and even quantify the changes in different types of polarization over time.