Prediction of MEA degradation in fuel cells for heavy-duty vehicle applications based on driving cycle analysis and component-specific accelerated stress testing

To estimate the lifetime of polymer-electrolyte membrane fuel cells (PEMFCs) in heavy-duty vehicles (HDVs), a deep understanding of degradation mechanisms under realistic operating conditions is essential. We developed two different accelerated stress tests (AST) for HDVs: (1) The “All Component Aging Test” (ACAT) is based on a synthetic voltage, temperature and humidity profile to equally stress all components of the membrane electrode assembly (MEA). (2) The “Truck Driving Cycle Test” (TDCT) is based on real HDV driving data and applies moderate voltage, temperature, and humidity conditions as well as elevated differential pressure. Additionally, standardized U.S. Department of Energy (DoE) component-specific aging tests were performed for comparison. A commercial HDV MEA was subjected to all aging protocols. As a result, the MEA’s end-of-life (EoL) was reached in the ACAT after 2100 h due to catalyst layer degradation. In contrast, the lifetime determining factor in the TDCT (EoL after 1500 h) was membrane degradation. Interestingly, the DoE tests predicted the aging of the catalyst layer as lifetime-limiting, but did not identify the membrane as critical component. These findings demonstrate that standardized test protocols alone are no adequate substitution of application-specific ASTs to estimate the real-world durability of PEMFC MEA components.