Effect Of Temperature On Electrolyte Properties And Single Cell Performance Of Vanadium Redox Flow Battery

The temperature has a significant effect on the performance of all vanadium redox flow battery,which has been reported in the existing research.However,it is an unanswered question that how and why does the temperature affects the battery.In the all vanadium redox flow battery,the reaction and transfer of the electroactive material is a complex multi field coupled heat and material transfer phenomenon.What's more,in the key area of the battery,the ion transfer process of the electroactive substance directly affects the performance of the battery.In this study,the material transfer modes in the electrode and the membrane region were been analyzed theoretically.It was proposed that the main material transfer mode of the ions who react on the surface of the electrode is diffusion process,while the material transfer mode of the ions who cross the membrane is electro migration.The experiment measured the change trend of the material transfer characteristics of the ions in electrolyte with changing temperature.The general rules of the influence of temperature on the electro migration of hydrogen ions,the electro migration of vanadium ions and the diffusion process of vanadium ions were been revealed.The data show that higher temperature is more conducive to the transfer process of ions,and the weaken diffusion of vanadium ions on the surface of the electrode at low temperature has a significant restriction on the electrode reaction.The conversion formula for measuring the SOC of battery by open circuit voltage method was been improved.A single battery test-bed was been built,and the on-line monitoring of SOC was realized by introducing extra single cell in the loop.The performance of the single cell at different ambient temperature at-10?50? has been test,respectively.The corresponding relationship between the general performance of the charge discharge of a single cell and the temperature was been obtained.By analyzing the change interval of battery SOC during charging and discharging process,the concept of battery capacity utilization is proposed.What's more,the corresponding relationship between the capacity utilization and temperature was been analyzed.In this paper,the general ways that the temperature can change the performance of the battery by affecting the material transfer of the ions was been revealed.The effects of the use of additives on the ionic material transfer characteristics of the electrolyte and the performance of the single cell were been analyzed.It provided a theoretical guidance for further analysis and establishment of a theoretical model for the effect of temperature on the performance of all vanadium redox flow battery to improving the temperature adaptability.