Abstract
Keywords
Ultracapacitors, cycle life, electrothermal modelling, Hybrid Electric Vehicles
Abstract
In this paper, ultracapacitors power cycling results are presented. First, current profiles are specified for power cycling tests. They take into account at the same time the ultracapacitors features and their use as peak power source in HEV applications. Then, electro-thermal characterization is done. Thanks to convenient electrical and thermal models, two current profiles are applied to 2600F devices. Results demonstrate that a thermal steady state is properly obtained and so power cycling is carried out. The results of 25,000 cycles illustrate that impedance real part and capacitance are a significant parameters for ageing quantification. Also, a difference in ageing is noticed which is due to a difference in current profiles discontinuity. Finally, ultracapacitors demonstrate a good cycle life. Since, the manufacturer specifications are not yet reached. But, according to the trend of the obtained results, the announced cycle life will not be reached.