Electrical and energetic characterization of supercapacitors

The supercapacitor can be characterized by a capacitance in series with a resistance. The capacitance represents its ability to store electrical energy. The series resistance represents the Joule losses. These losses cause the component s temperature to rise. The increase in temperature of the supercapacitor can degrade its energy performances and accelerate its aging. 

When the supercapacitor is discharged at constant cirrrent, the eqrrivalent series resistance causes a voltage drop at the beginning of discharge. Then, the voltage decreases due to the capacitive effect. Regarding the measurement of Ri, it is 

F ure 4.4. Procedure for measuring the equivalent series resistance according to the IEC 62391 standard 

AUs is determined by the intersection between the tangent of the discharge curve at constant current and the vertical line originatmg at the start of the discharge 

The equivalent capacitance is calculated using the following expression  

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