Abstract: A single cell of vanadium redox flow battery (VRB) was investigated on-line by the transient-boundary voltage method. An equivalent circuit model was established using the voltage source，resistor，and a resistor in parallel with the capacitance of three-part series. The effects of current density and state of charge (SOC) on equivalent circuit components values were investigated. The experimental results showed that the polarization resistance decreased slightly with increasing current density，and reached its maximum in the beginning of charge and the end of discharge. Compared with polarization resistance，ohm impedance in the charge/discharge process was the highest respectively 1.905Ω?cm2 and 2.139 Ω?cm2. It was the main factor leading to voltage loss. The transient boundary voltage method is a simple and effective way of characterizing performance of vanadium redox flow battery.

Key words: all vanadium redox flow battery (VRB), transient-boundary voltage method, equivalent circuit model, ohm resistance, polarization resistance

摘要： 国内首次采用暂态边界电压法在线研究了全钒液流电池（VRB）的特性，建立了由电压源、电阻以及一个电阻与电容并联的3部分串联而成的等效电路模型；研究了电流密度和荷电状态（SOC）对等效电路元件的影响。实验结果表明，极化阻抗随电流密度的增加有轻微下降，在充电初期和放电末期达到最大值。与极化阻抗相比，充、放电过程中的欧姆阻抗最大，是导致电压损失的主要因素，分别为1.905Ω?cm2和 2.139 Ω?cm2，暂态边界电压法是一种简单且有效的表征全钒液流电池性能的新方法。

关键词: 全钒液流电池, 暂态边界电压法, 等效电路模型, 欧姆阻抗, 极化阻抗