Study on thermal behavior of vanadium redox flow battery at low temperature to prevent precipitation

A parametric study on temperature distribution of vanadium redox flow battery was examined to understand thermal behavior at cold climate. Based on the results, an empirical equation was developed to anticipate the minimum temperature depending on the operating conditions. First, temperature distribution in each electrode was examined in charge and discharge process. Temperature increased at discharge process, but decreased of 2.11 degrees C compared to outside temperature at charge process. Therefore, precipitation can be found during charge process. Next, effect of operating conditions on the minimum temperature is analyzed. When current density is 100 mA/cm(2), the minimum temperature decreased of 2.5 degrees C compared to outside temperature due to large amount of endothermic reaction. On the other hand, as flow rate increases, minimum temperature increased. Because high flow rate promotes heat transfer between the cell and electrolyte. The effect of cell design also considered. As active area increases, the minimum temperature decreased 2.12 degrees C compared with outside temperature because more endothermic reaction occurs in large area. The effects of porosity, however, is negligible because of interaction between changes in flow configuration and endothermic reactions. Finally, an empirical equation is developed to know the proper operating conditions for given cell design to prevent precipitation due to cold outside temperature.