Predicting Platinum Dissolution and Performance Degradation under Drive Cycle Operation of Polymer Electrolyte Fuel Cells
Heather Baroody, Erik Kjeang
Abstract
A protocol is presented that allows for fuel cell performance degradation to be determined based on a vehicle drive cycle. Four stages are outlined beginning with the conversion of vehicle velocity data to a cell voltage profile. The amount of platinum dissolved in the system and oxide coverage on platinum particles are simultaneously calculated by considering several degradation mechanisms including Ostwald ripening and platinum particles loss to the membrane. The platinum loss is used to determine the Electrochemically Active Surface Area (ECSA) loss in the catalyst layer. The voltage loss due to platinum degradation is then determined from the ECSA data. The results show that longer times at higher upper potential limits lead to more platinum degradation and thus performance loss as expected. Accelerated Stress Test data is reproduced within the acceptable error. The model is applied to real-world data from a vehicle drive cycle showing that the model simplifications and assumptions outlined are reasonable and prove predictive capabilities. Although more experimental data would be beneficial to fully validate the model, the present work provides a complete, physics-based catalyst degradation model that can be integrated with performance models to predict durability and optimize future system designs and operating conditions. This paper is part of the JES Focus Issue on Proton Exchange Membrane Fuel Cell and Proton Exchange Membrane Water Electrolyzer Durability.