Modeling and transient degradation of proton exchange membrane fuel cells

Abstract

This thesis presents a model based approach to describe proton exchange membrane (PEM) fuel cell degradation with time. This degradation study involves analysis of voltage and current profiles of PEM membranes under transient load conditions. The data is collected from 80 membranes in an Independence1000 1000W PEM system over the life span of the membrane. The thesis also presents PEM fuel cell models developed and validated on a 500W SR-12 commercial PEM stack. Several static models from the literature are reviewed in terms of physical effects, parameterized for identification, and compared using measured data from the commercial PEM stack. The dynamic model is obtained by extending static current voltage profiles to include temperature dependence, and by dynamically modeling the temperature of the membrane. After inspecting all these models a simplified model is used for analyzing PEM fuel cell degradation and changes in physical phenomena in fuel cell observed over a period of time.