Real-time capable transient model of liquid water dynamics in proton exchange membrane Fuel Cells
Andraž Kravos, Ambrož Kregar, Željko Penga, Frano Barbir, Tomaž Katrašnik
Abstract
Optimal control of liquid water dynamics plays an instrumental role in achieving optimised performance and prolonged lifetime of PEM Fuel Cells (PEMFC). Tackling these challenges calls for precise on-line monitoring and control tools such as coupled virtual observers taking into consideration also liquid water dynamics. The latter proves to be especially challenging to model due to varying retention and removal rates of liquid and gaseous water depending on the operating conditions thus representing a longstanding knowledge gap. To fill this gap, this contribution presents derivation of a 1D+1D system level physically motivated two-phase model of PEMFC, which enables consistent treatment of liquid water dynamics on the system level in all seven most influential regions of the PEMFC, namely membrane, anode and cathode channels, GDLs, and catalyst layers, while exhibiting real-time readiness with real-time factor of 0.0449. The model is extensively tested on single-cell data, which consists of five sets of experiments with different operating regimes and durations. Overall results exhibit good agreement with experimental data in all of the performed tests with R 2 factors larger than 0.95. Newly developed features of the model enable its use in development of advanced control methodologies and hardware-in-the-loop as well as digital twin applications. • System-level physically motivated two-phase PEMFC model is derived. • Model considers retention and removal rates of liquid and gaseous water. • Identifiability of calibration parameters was proven by sensitivity analysis. • Model exhibits good extrapolation capabilities beyond calibrated operational area. • Newly derived model is applicable in on-line monitoring and control applications.