An optimal strategy of electrolyte flow rate for vanadium redox flow battery

► Electrolyte flow rate is a key factor that affects the performance of VRFB. ► An optimal strategy of electrolyte flow rate for VRFB is proposed. ► The purpose of the optimization is to improve system efficiency and keep high capacity. ► The system efficiency can be increased by 8% when keeping high capacity simultaneously. Electrolyte flow rate is a key factor that affects the performance of vanadium redox flow battery (VRFB). A kilo-watt class VRFB system is fabricated to investigate the effects of electrolyte flow rate on the performance of VRFB. The experiments show that the capacity increases, but the system efficiency decreases with the increase of electrolyte flow rate. An optimal strategy of electrolyte flow rate is proposed to improve the system efficiency and keep the high capacity simultaneously, which is corresponding to optimize the electrolyte flow rate at different stages of charge and discharge processes. The results show that the system efficiency can be improved as high as 8% when keeping high capacity simultaneously.