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German R.,CNRS Ampere Laboratory | Sari A.,CNRS Ampere Laboratory | Venet P.,CNRS Ampere Laboratory | Ayadi M.,French National Center for Scientific Research | And 3 more authors.
Microelectronics Reliability

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. © 2014 Elsevier Ltd. All rights reserved. Source

Ayadi M.,French National Center for Scientific Research | Ayadi M.,Laboratoire des Technologies Nouvelles | Briat O.,French National Center for Scientific Research | Lallemand R.,Laboratoire des Technologies Nouvelles | And 4 more authors.
Microelectronics Reliability

Great research effort is currently devoted towards enhancing performance and operating time of electrical vehicle (EV). Classic storage element in EV consists of accumulators, which allow a relatively high autonomy. However, the power capability of these devices can be considered as insufficient. Supercapacitors (SC) are a new promising storage system used in EV to minimize this lack thanks to their high power capability. One of the ageing cause for SCs for this application is the day/night cycling, that is why we study the impact of thermal cycling on SC performances in this paper. In this article, and in order to have a descriptive sample, impacts of three thermal cycling ageing test conditions are compared with obtained results coming from simple calendar ageing tests at constant temperature and voltage. The comparison is based on physics modelling parameters evolution in the Constant Phase Element (CPE) and Multi-Pore (MP) models. These parameters are calculated based on experimental measurements during calendar ageing tests up to 14,000 h and 6000 h, 10,000 h for thermal cycling tests. Finally, the study of modelling parameters highlights changes in the internal physical structure for both ageing tests. © 2014 Elsevier Ltd. All rights reserved. Source

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