SSALT-Batt: Step-stress accelerated life testing experiments for batteries

The importance of lithium-ion batteries in areas like electrified transportation and storage of sustainable energy is undoubtful. Their lifetime and lifetime prediction in real application is crucial for reliable operation and successful market introduction. As ageing tests using normal operation conditions (NOC) are very time and cost intensive, accelerated life testing (ALT) experiments are a powerful alternative, widely used to determine the lifetime distributions of highly reliable products.

In this project we aim at developing optimal constant stress ALT procedures (CS-ALT) to predict lifetimes of batteries cells, while controlling the duration of the experiments and the quality of inferential results for the lifetimes under NOC. In particular the lifetime-stress relationship will be in focus. An accurate link model that extrapolates the estimations and predictions from accelerated to NOC will be specified through extensive simulation studies and use of experimental data with different types of batteries. The fundamental knowledge for getting orientation to set-up the simulations framework and the follow-up experiments is aimed to be gained in our approach. Another essential part of ALT procedures are the step-stress ALT (SS-ALT) experiments. Under a SS-ALT experiment, the stress level is increased at intermediate time points of the experiment. The applicability of SS-ALT experiments and their usage in testing of batteries cells will also be explored.

Project Partners and Principal Investigators:

► ISW (Institut für Statistik und Wirtschaftsmathematik)

Prof. Dr. Maria Kateri

Lehrstuhl für Statistik und Stochastische Modellierung

Pontdriesch 14-16, 52062 Aachen

@: maria.kateri@rwth-aachen.de, Tel.: +49-241-80-97950, Fax: +49-241-80-92259

Prof. Dr. Udo Kamps

Lehrstuhl für Statistik

Wüllnerstr. 3, 52062 Aachen

@: udo.kamps@rwth-aachen.de, Tel.: +49-241-80-94576, Fax: +49-241-80-92848

► ISEA (Institut für Stromrichtertechnik und Elektrische Antriebe)

Prof. Dr. Dirk Uwe Sauer

Lehrstuhl für Elektrochemische Energiewandlung und Speichersystemtechnik

Jaegerstr. 17-19, 52066 Aachen

@: DirkUwe.Sauer@isea.rwth-aachen.de, Tel.: +49-241-80-96977, Fax:+49-241-80-92203