Modeling and Optimization of Vanadium Flow Batteries Incorporating Variable Permeability and Resistance

Abstract

The vanadium flow battery employing vanadium element of different valences as the active substances for both sides is a promising device for large-scale energy storage applications. In this paper, a vanadium flow battery dynamic model incorporating the variable vanadium ion permeabilities and cell resistance is proposed, and the cell performance is subsequently analyzed and optimized. The variation of permeability and resistance is tested, and a laboratory flow cell is engaged for simulation. The results demonstrated that: (i) the proposed model behaves a superior prediction precision in comparison with the existing models with constant permeability and resistance; (ii) operated in temperature range of 25 °C and 35 °C is favored to achieve an improved energy efficiency; (iii) low and high operating temperatures are respectively preferred for vanadium flow batteries operated at low and high current densities. Such in-depth analysis can not only be highly beneficial to the operation and optimization of vanadium flow batteries to realize an enhanced performance, but offer a cost-effective modeling method with high accurate prediction precision to understand the characteristic and behavior of vanadium flow batteries within a wide operating temperature as well, thus avoiding large amounts of experimental testing that expends extensive materials and time.