液流电池SOC测定用指示电极的电位稳定性

Potential stability of indicator electrodes for SOC measurement of all-vanadium redox flow battery

全钒液流电池电解液荷电状态的测定是液流电池运行控制和电解液维护管理的一项重要内容。在电极电位法或电位差法测定全钒液流电池荷电状态的技术中,电解液荷电状态的测定是通过测定指示电极的电极电位来测定的。由于指示电极的电极电位在电解质溶液中达不到稳定,电极电位值随着时间发生漂移,给电极电位的测量带来误差,也因此对荷电状态测定造成显著的误差。通过实验测定了各种指示电极在正极钒电解液中的电位稳定性,结果表明玻碳电极在正极钒电解液中的电位稳定,适宜作为正极电解液荷电状态测定用的指示电极。

The state of charge is one of monitoring items for the operation control and electrolyte maintenance of all-vanadium redox flow battery. The state of charge of the electrolytes can be monitored by measuring the potential of indicator electrodes in the electrolytes. In many cases, the potential of indicator electrodes does reach their stable value even soaked in electrolytes for several hours. The shift of the indicator electrode potential value will result in an error in the measured potential value of indicator electrode, and then also result in an error in the value of state of charge calculated from the measured potential data. The potential stability of various indictor electrodes in positive electrode electrolytes was investigated. It is found that the glassy carbon electrode has very stable potential after long time soaking in positive electrode electrolyte and is suitable for the monitoring of state of charge of positive electrode electrolyte.