A spatially resolved fuel cell stack model with gas-liquid slip phenomena for cold start simulations

This paper proposes a novel fuel cell stack model for system simulation of the cold start operation. The stack model features the option of spatial resolution in two directions and can simulate two-phase effects that are prone to occur during cold start. These effects include: the sorption process in the triple-phase zone between the membrane and the catalyst layer; the condensation, freezing and evaporation in the porous layers; the two-phase flow in the gas channels with a gas-liquid slip model. Compared to a 0D lumped model, the proposed stack model provides a more detailed view of the onset of freezing and liquid saturation. In a freeze start simulation from −20 °C, the Rapid-Warmup-Operation published by Naganuma et al. [1] is applied and demonstrated as an effective way to quickly elevate stack temperature to +5 °C within 30 s. The stack model illustrates in detail the physical phenomena in the cold start and can be further integrated into a powertrain model for drive cycle analysis.