Supercapacitors (SC) are power devices used as transitory energy sources for peak power applications such as braking energy recovering in hybrid transports. They are subject to electrochemical ageing processes which affect their performances and reliability. Consequently, the main influence factors on SC ageing kinetic are temperature and voltage. Some ageing law based on experiment results have already been produced (for instance the Eyring law) but are not precisely related to physical considerations. In this article, we propose to use an ageing law which links ageing kinetic with the growth of an interface layer between the electrodes surface and electrolyte, called here SEI (Solid Electrode Interface) layer. In order to have a representative sample, 81 commercial supercapacitors coming from 3 different manufacturers will be tested through floating ageing tests at different voltage and temperature constraints. All presented components are manufactured with the most widespread SC technology (double layer SC using activated carbon for electrode and acetonitrile). The fitting of SC experimental ageing results and SEI ageing law is achieved. Then the effect of temperature and voltage on SEI ageing law parameters is performed.