间歇供液在钒电池储能系统中应用的实验研究

Experimental Research of Batch Operation in Vanadium Redox Battery System

实验以脉冲驱动泵对单个全钒氧化还原电池(vanadium redox battery,VRB)进行间歇供液。通过改变供液占空比,得到不同工况下的VRB恒流充放电曲线,分析这些充放电曲线可知:1)不同占空比供液时电流效率保持不变;2)占空比1/3供液时,系统相对泵损减少超过50%,电压效率和单电池能量效率分别只下降5.1个百分点和4.8个百分点。实验采用间歇供液方式使VRB系统泵损大大降低,同时保持了钒电池的基本性能。根据钒单电池实验结果,和相关资料中系统泵损约占VRB系统放电能量的9%,以此数据作为泵损标准,可推断出将间歇供液方式运用于钒电堆系统时,VRB系统预估输出效率。实验结果表明供液占空比2/3时,VRB系统输出效率最高,达到81.2%。

Batch operation was realized in a full vanadium redox battery （VRB） by driving two pumps with pulsating current. By varying the constituent periods in different pulsating flow conditions under different duty cycles, the respective charge-discharge curves of the VRB obtained. By analyzing these charge/discharge curves, we deduce that, the current efficiency is unchanged; then, significant reductions of more than 50% in pumping energy can be achieved whilst suffering an energy efficiency loss of only 4.8% and voltage efficiency loss of only 5.1% in a 1/3 duty cycle. The pulsating fluid supply can save the pump＇s energy consumption greatly, which otherwise cost around 9% of the discharge power as obtained from relevant external studies, while retaining basic performance of the VRB. Based on the results for the single cell, the data for pump energy consumption is chosen as the arbitrary standard. The estimated system efficiencies for a VRB stack are hence extrapolated and presented subsequently. The final results show that the system output efficiency of VRBs is capable of reaching a maximum of 81.2% in a 2/3 duty cycle.