恒流放电法测量超级电容器静电容量的影响因素分析与不确定度评定

静电容量是超级电容器的主要电气参数之一,相关标准中均推荐采用恒流放电法对超级电容器静电容量进行测量。介绍了恒流放电法的测量原理和测量电路,通过实验分析了放电电流、充电电流、初始电压对测量结果的影响,并对静电容量测量不确定度进行了评定。结果表明:放电电流对测量结果有较大影响,静电容量随放电电流的增大而减小;充电电流和初始电压对测量结果的影响影响较小;恒流放电法测量静电容量的相对扩展不确定度为2.2%(k=2)。

Analysis and Uncertainty Evaluation of Capacitance Measurement of Supercapacitors by Constant Current Discharge Method

Capacitance is one of the main electrical parameters of supercapacitors, and constant current discharge method is recommended to measure the capacitance of supercapacitors in related standards. Influences of the charging and discharge current, the initial terminal voltage of the capacitor were analyzed based on experiments. And uncertainty of the capacitance measurement was evaluated. Results show that the discharge current has a great influence on the measurement, and the capacitance decreases as the discharge current increases. The charging current and initial voltage have a small effect. The expanded uncertainty of capacitance measurement is 2.2% by constant current discharge method with a confidence factor of 2.