A Revisit to Supercapacitor Capacitance Measurement Method 1A of IEC 62391-1

This paper revisits the supercapacitor capacitance characterization method 1A of the IEC standard 62391-1. For comparison, an alternative method using the total charge stored in the supercapacitor is proposed. These two methods are applied to three supercapacitor samples with different rated capacitances from different manufacturers at different terminal voltages. Results show that the capacitance determined using the IEC method decreases when the discharge current increases. Besides, the capacitance measured using the IEC method is lower than that estimated using the total charge method. These observations are explained by analyzing a five-branch RC ladder circuit model capturing the porous electrode structure and the charge redistribution process of supercapacitors.