Monitoring fading rate of ultracapacitors using online characterization during power cycling

This paper deals with the ageing quantification of ultracapacitors in cycle-life tests. Typical micro- and mild-hybrid applications have been used to specify the test profiles in agreement with power requirements. Since ultracapacitors lifetime depends on the temperature, these profiles are adjusted to induce a given self-heating at the beginning of the power cycling tests. Ageing is evaluated thanks to the measurements of the electrical parameters changes. The good reproducibility of the characterization methods has allowed us to monitor the fading rate of ultracapacitors, from two manufacturers, with the proposed current profiles.