The all-vanadium redox flow battery (VRFB) has been considered as one of the most promising rechargeable battery for large-scale energy storage system that can be used with renewable energy sources, such as wind and solar energy, for electrical energy storage and distribution. Since it is able to withstand average loads, high energy efficiency (EE), and high power output, the battery exhibits good transient behavior and sustains sudden voltage drop. The dynamics of the battery is governed by the equations of fluid mechanics, electrodynamics, and electrochemistry. In this context, earlier efforts reported in the literature were mainly focused on simulation of the variation of the charge/discharge characteristics of the cell. There is a need to optimize the cell parameters so as to improve the cell performance. The performance of the battery is also studied numerically with the two-dimensional (2D) isothermal transient model. This model is used to predict the effects of change in electrolyte flow rate, concentration, electrode porosity, and applied current. The efficiency analysis for the effects of concentration shows that maximum coulombic, voltage, and energy efficiencies have been achieved in case of higher concentration. Numerical model results are validated with the available experimental result, which shows good agreement.