Simulation of cathode catalyst durability under fuel cell vehicle operation –Effects of stack size and temperature

In this work, a fundamental cathode catalyst degradation model is developed in order to simulate fuel cell stack durability under realistic vehicle operation. A dynamic platinum degradation model featuring platinum dissolution and redeposition is developed to account for the Ostwald ripening phenomenon. The model is then calibrated for a variety of accelerated stress test data with different upper and lower potential limits and temperatures. Next, a case study of fuel cell transit bus operation in the city of Victoria, B.C., Canada is carried out to investigate the effects of stack size and temperature on the cathode catalyst durability. To this end, the required power density and cell voltage are calculated from the drive cycle considering vehicle dynamics and specifications. Larger stacks are found to experience higher upper potential limits; thus, showing lower lifetimes. The cathode lifetime is predicted to grow 379% at 80°C if the stack nominal power is lowered from 396 to 132 kW while the performance requirement is met. The temperature is also shown to have a tremendous impact on the cathode lifetime. A temperature drop from 80 to 60°C results in 154% cathode lifetime enhancement for a stack nominal power of 264 kW.