Dynamic modeling of vanadium redox flow batteries: Practical approaches, their applications and limitations

Vanadium redox flow batteries (VRFBs) have been in the focus of attention of the energy storage community over the past years. Adequate, reliable and user-friendly mathematical models are required for the development and optimal application of this type of battery. A large amount of literature has been devoted to dynamic models of VRFBs, but insufficient attention has been paid to the comparison and critical analysis of their applicability. The article provides a comprehensive overview of available dynamic models, comparing their applicability for real-time simulation of industrial-scale vanadium redox flow batteries. In addition, a methodology for the models comparison is proposed, which takes into account different modes of operation and allows to determine the applicability range of a particular model. The results of the study show that lumped-parameter models with crossover performs well for simulating battery dynamics in the wide range of operating conditions: state of charge (SOC) - (0.1-0.8), load current - (20-290 mA/cm2 ), flow velocity - (0.4-2.7 cm/s). Also, such models can be tuned even if some physical parameters of the battery components (e.g. electrodes and membrane) are unknown. The results obtained can be used to provide more accurate simulation of vanadium redox flow batteries in real-time monitoring and control tasks, when accuracy and performance are important