Evaluation and Modeling of Long-Term Endurance Measurement on Electric Double Layer Capacitors to Increase Reliability of Lifetime Predictions

Sustainability in the electrical industry and product reliability are fundamentally dependent on product lifetime predictions. Long-term DC voltage endurance measurements at two different temperatures on various commercial electric double-layer capacitors are presented, discussed, and used to develop a deterioration model suitable for estimating lifetime. Capacitors were tested under constant voltage for approximately 1 year at 65 °C and about 4 years at room temperature. To describe the deterioration in terms of capacitance and the equivalent series resistance, a phenomenological model is proposed and tested against measurements taken at room temperature. The proposed model is based on a general exponential relation with a time-dependent deterioration rate. The model is tested against long-term measurements with constant and time-dependent temperature acceleration factors. Analysis of capacitance and equivalent series resistance measurements shows a time or deterioration dependence in the temperature acceleration factor and different phases of deterioration.