THE INVESTIGATION OF THERMAL BEHAVIOR IN A VANADIUM REDOX FLOW BATTERY DURING CHARGE AND DISCHARGE PROCESSES

The aim of this study is to investigate the effects of operating parameters on the thermal behavior and battery performance of a vanadium redox flow battery during charge and discharge processes, separately. Two different cases are discussed in the two dimensional numerical model developed to achieve this goal. In the first case the operating temperature is increased from 10 degrees C to 40 degrees C (stepping by 10 degrees C) while keeping constant at 2M the molar concentration of electrolyte. In the second case, the molar concentration of electrolyte is varied from 1.25M to 2M (steps by 0.25M), as the operating temperature is constant at 40 degrees C. In order to bring out the thermal behavior of vanadium redox flow battery by changing these operating parameters during charge and discharge processes, the variations of irreversible-reversible heat sources and joule heating source inside the porous electrodes and the temperature distributions are deeply analyzed. The obtained results show that the battery performance is enhanced by changing with both operating parameters and the values of irreversible and reversible heat sources in the negative electrode are more than in the positive electrode during both processes. While the joule heating source increases with increasing of the operating temperature, it decreases with increasing of the molar concentration of electrolyte. In addition, a big difference in the temperature inside both electrodes does not occur during charge and discharge processes.