Drive Cycle‐Based Accelerated Stress Tests for Heavy Duty Fuel Cell Vehicle Applications

ABSTRACT Fuel cells in heavy‐duty vehicles are susceptible to degradation and are significantly influenced by driving patterns. Accelerated stress tests (ASTs) are useful to identify these degradation mechanisms and aid the development of degradation‐resistant control strategies for FC stacks. Conventional ASTs are designed to address material degradation over time, but the dynamic stresses encountered by the fuel cell during real‐world driving occur under different operating conditions. This work proposes an algorithm to generate a drive cycle‐based AST to face this challenge and provides an efficient method for assessing fuel cell durability. Our method incorporates voltage cycling, high load operation, and idling periods, weighted to reflect the distribution of these conditions for a specific drive cycle. The formulated ASTs are given as inputs to a one‐dimensional catalyst layer degradation model, which estimates the loss of electrochemical surface area (ECSA) based on platinum (Pt) oxidation, Pt dissolution, Pt particle size distribution, and carbon corrosion. A postmortem analysis of single cells, exploiting identical location‐transmission electron microscopy (IL‐TEM), was performed to investigate the underlying degradation processes and validate the accuracy of the modeling outcomes. Good agreement was observed between the model and experimental data, demonstrating the predictive capability for ECSA loss across a range of cell temperatures and relative humidity levels. Comparing the generated ASTs and representative drive cycle degradation characteristics, it is evident that a similar amount of ECSA loss can be achieved in a significantly shorter period. In addition, we demonstrate an accelerated degradation algorithm capable of simulating long‐term fuel cell degradation, producing ASTs that are representative of real‐world driving conditions.