Impact of high frequency current ripple on supercapacitors ageing through floating ageing tests

• We performed floating ageing on different 3000F commercial supercapacitors.
• We permanently added a HF current ripple on floating constraints.
• We compared the results of the two ageing tests.
• We proposed possible interpretations of HF current effect on ageing processes.

Supercapacitors (SC) are energy storage systems (ESS) which are appreciated in hybrid vehicle. Hybrid vehicles electrical network is based on DC–DC converter which imply HF current ripple. This article proposes through ageing tests exploitation to study the influence of hybrid car HF current ripple on SC ageing (with current ripple of the same order of magnitude and frequency than for hybrid onboard network). Impedance parameter evolution is used to monitor SC state of health. Obtained results show that current ripple has significant effects on SC ageing kinetic and reliability (packaging failures). The packaging failures are linked to overpressure induced by HF current ripple. Finally a new model for SC ageing under current ripple is proposed thanks to electrolyte degradation by an electrical resonance process.