Mathematical Description of Voltage Decay Rates in PEM Fuel Cells

Abstract

In the fuel cell community there is no common way to describe degradation or voltage decay rates in durability test. This leads to a variety of possible approaches used to calculate voltage decay rates making the comparability of different tests difficult, especially when durability test are regularly interrupted by diagnostics or soak times in order to recover reversible voltage losses. Our study tries to address this issue by a mathematical description of voltage loss rates in PFSA based MEAs with Pt catalyst. In the presented approach we describe the decay rate changes by fitting an exponential and a linear decay curve to the experimental data after each refresh step, see right panel of figure. The obtained fit parameters allow a clear separation and an in-depth analysis of the different contributions of the decay rate.