A Mathematical Model for Predicting the Life of PEM Fuel Cell Membranes Subjected to Hydration Cycling

TL;DR

This paper presents a mathematical model to predict the lifespan of PEM fuel cell membranes under hydration cycling, accounting for humidity variation, mechanical stress, and damage accumulation.

Contribution

It introduces a comprehensive modeling framework combining humidity distribution, stress analysis, and damage prediction for membrane lifetime estimation.

Findings

Model accurately predicts membrane lifetime under various RH cycling conditions.

Application to GORE-SELECT membrane demonstrates practical utility.

Highlights importance of mechanical properties and hydration amplitude in durability.

Abstract

Under typical PEM fuel cell operating conditions, part of membrane electrode assembly is subjected to humidity cycling due to variation of inlet gas RH and/or flow rate. Cyclic membrane hydration/dehydration would cause cyclic swelling/shrinking of the unconstrained membrane. In a constrained membrane, it causes cyclic stress resulting in mechanical failure in the area adjacent to the gas inlet. A mathematical modeling framework for prediction of the lifetime of a PEM FC membrane subjected to hydration cycling is developed in this paper. The model predicts membrane lifetime as a function of RH cycling amplitude and membrane mechanical properties. The modeling framework consists of three model components: a fuel cell RH distribution model, a hydration/dehydration induced stress model that predicts stress distribution in the membrane, and a damage accrual model that predicts membrane life-time. Short descriptions of the model components along with overall framework are presented in the paper. The model was used for lifetime prediction of a GORE-SELECT membrane.