Study on specific effects of high frequency ripple currents and temperature on supercapacitors ageing
Résumé
Although supercapacitors can store less energy than batteries for an equivalent weight, they are particularly interesting for hybrid vehicles which need high power storage systems (for braking energy recovering or stop and start systems). In hybrid vehicle power network supercapacitors are subject to high frequencies ripple currents due to the presence of DC"DC converters. This article studies through ageing tests if the high frequency ripple currents are a factor of overageing for supercapacitors. The results tend to show that high frequency current ripples are transparent in term of ageing. These results are interesting for industrial use as they prove that the supercapacitors can be inserted in polluted power networks without particular precautions. Complementary ageing test focus on the effects of temperature at very low voltage on supercapacitors ageing. They clearly show that the increase of supercapacitor resistance is only partly linked to the capacitance loss.