First step in the reliability assessment of ultracapacitors used as power source in hybrid electric vehicles

Regarding the new power requirements in hybrid electric vehicles, ultracapacitors seem to be very attractive. The examination of their existing characteristics, combined with the pulsed charge-discharge current mode, leads us to propose an original approach for electro-thermal characterization of ultracapacitors. Therefore, a dedicated test bench has been designed allowing both electric and thermal behaviour investigations. The principle of this study is to investigate the ultracapacitors thermal behaviour thanks to several specific cyclic current profiles. The use of these profiles will constitute the very first step in an assessment of the ultracapacitors reliability devoted to power source operation in automotive applications.