Abstract: The operating parameters of VRFB are important factors affecting the performance of the battery. The existing equivalent circuit model often fail to study the effect of flow rate on the performance and efficiency of VRFB due to the lack of coupling with hydrodynamic model, so they are not perfect in practical projects; In addition, the pure hydrodynamic model only studies the relationship between flow rate and pump loss, but the electrical characteristics of the battery itself are too simplified, which cannot fully reflect the characteristics of VRFB system. Therefore, the equivalent circuit model of the basic principle and the equivalent loss of vanadium battery was established based on basic principle and the equivalent loss of VRFB while the hydrodynamic model was established based on mechanical loss and structure parameters in this paper. Based on the equivalent model of the VRFB system, the influence of the operating parameters of the battery on the battery performance was analyzed. The simulation analysis shows that the optimal flow rate during charging-discharging is a function of the state of charge. According to this phenomenon, the flow is controlled piecewise with the change of SOC. Through the analysis of simulation results, the efficiency of VRFB can be effectively improved by the optimal operation strategy of subsection control flow rate according to the change of SOC.

Key words: all vanadium redox flow battery, equivalent model of vanadium battery system, operating parameters, optimal control