全钒液流电池的旁路电流测量与仿真

Shunt current measurement and simulation of all-vanadium redox flow battery

全钒液流电池的旁路电流引起电荷损失、降低电池效率,升高电堆两端的单电池电压,导致副反应发生和减少电池寿命。目前,关于旁路电流的理论研究较多,但是测量数据较少。首先,为了测量旁路电流,采用双极板中嵌入电流表的方法监测流过双极板的电流,该电流与外部电流之差即为旁路电流,因此,能够排除电解液交叉污染引起的电荷损失干扰。其次,建立了全钒液流电池系统的改进模型,将旁路电流的仿真结果和实测数据进行比较,验证了改进模型的合理性,并对各单电池的电压、电流时间变化及电堆内电压分布进行仿真。同时,对总管电阻、支路电阻、电池内阻对电池的电流效率、电压效率、电池效率的影响进行了分析,得出为了提高电池的效率,有必要增加总管电阻,降低电池内阻的结论。该模型和实验可用于液流电池设计,为高性能液流电池技术发展提供理论依据。

The shunt current in all-vanadium redox flow battery(VRFB) causes charge loss,reduces battery efficiency,and increases the voltage of single battery at both ends of the stack,leading to side reactions and reducing battery life.First,we use a special bipolar plate to access the ammeter to measure the shunt current.The value of shunt current does not involve cross contamination due to the charge loss portion.Secondly,an improved model of vanadium flow battery system is proposed based on the widely used bypass current equivalent circuit model.According to the comparative analysis of simulation and measurement results,the rationality of measurement methods and models is verified.In order to improve the efficiency of the battery,it is necessary to increase the main resistance and reduce the internal resistance of the battery.The model can be used in the design of liquid flow batteries and provide a theoretical basis for the development of high performance liquid flow batteries.