A Life Model for Supercapacitors

Supercapacitors provide high-power energy storage for electrical systems. The expected useful life of a supercapacitor is related to the oxidation of functional groups on the graphite electrode surface during usage, and it is highly dependent on operational voltage and temperature. In this paper, a life model is developed for commercial supercapacitors. The model incorporates a new voltage multiplier to describe the combined effects of temperature and voltage on supercapacitor life. Accelerated testing was conducted to obtain the time to failure of supercapacitors over a range of voltage and temperature conditions, validate the life model, and compare the model with two previously established capacitor life models. Failure was defined by a 30% decrease in capacitance or a 100% increase in equivalent series resistance.