Material characterization and fatigue lifetime prediction of a reinforced PEM fuel cell membrane

Date
2024
Journal Title
Journal ISSN
Volume Title
Publisher
University of Delaware
Abstract
Proton Exchange Membrane (PEM) fuel cells are pivotal in advancing clean energy technologies due to their high efficiency and minimal environmental footprint. However, a significant barrier to their widespread adoption is the durability of the fuel cell membrane, which degrades both mechanically and chemically during regular operation. The mechanical degradation is largely correlated to the repeated swelling and deswelling of the membrane due to varying hygrothermal loads. The introduction of a composite membrane by inserting an inert reinforcement layer has improved its chemical and mechanical stability. This study investigates the factors influencing reinforced membrane failure due to mechanical degradation in PEM fuel cells under different environmental conditions. ☐ This thesis encompasses a detailed material characterization of the membrane to understand its viscoelastic-elastoplastic and hygrothermal expansion properties. Additionally, a water transport model was developed to incorporate the spatio-temporal distribution of water in a membrane. Building on this, a representative volume finite element model of a Fuel Cell stack was created to predict the fatigue crack initiation of the membrane due to a pre-existing catalyst layer flaw. This was done by calculating the plastic dissipation energy (PDE) accumulation in a membrane in the vicinity of a flaw, under fatigue loading. The theoretical predictions were compared with experimental data to validate the model. The effects of temperature, humidity and clamping pressure on the PDE accumulation were examined. The findings highlight the importance of optimizing operational parameters to enhance the longevity of PEM fuel cells. ☐ This work contributes to the development of more durable PEM fuel cells by providing insights into the mechanical behavior of the membrane under various operating conditions. The implications of this research can have a positive impact on improving fuel cell reliability, thus advancing the feasibility of PEM fuel cells for commercial and industrial applications.
Description
Keywords
Fatigue, Fuel cells, Solid mechanics, Proton Exchange Membrane, Hygrothermal loads
Citation