A comprehensive study in experiments combined with simulations for vanadium redox flow batteries at different temperatures

Abstract

Ensuring the appropriate operation of Vanadium Redox Flow Batteries (VRFB) within a specific temperature range can enhance their efficiency, fully exploiting the advantages of renewable energy. This study employs a comprehensive approach combining experimentation and simulation to systematically investigate the impact of temperature on VRFB performance. Experimental evaluations of VRFB performance across various temperatures were conducted through charge and discharge experiments, electrochemical impedance spectroscopy, hydraulic pressure drop testing, and cycling charge and discharge trials. Additionally, a three-dimensional multi-field coupled model was developed to provide a theoretical analysis and elucidate VRFB performance under varying temperature conditions, incorporating temperature-dependent variations in the physical parameters of different components. The results suggest that in VRFB systems, an increase in temperature leads to a reduction in overpotential and pressure drop, resulting in improved system efficiency, albeit accompanied by a slight decrease in Coulombic efficiency. Furthermore, compared to ohmic overpotential and electrochemical overpotential, the impact of temperature on concentration overpotential appears to be relatively insignificant. Increasing the flow rate or temperature could contribute to a more stable degradation rate of capacity and Coulombic efficiency during the battery cycling process. Higher flow rates enhance the voltage efficiency of the battery, with the degree of improvement decreasing as temperature increases.