Predicting and Extending the Lifetime of Li-Ion Batteries

Battery and EV manufacturers carry out extensive long-term tests to estimate the lifetime of the battery and base warranty durations on those tests. The long duration of these tests slows progress in the research and development required to improve the lifetime of Li-ion batteries. This paper shows that accurate measurements of coulombic efficiency (CE) and impedance spectra of Li-ion batteries, that take a few weeks to acquire, can be used to rank the resulting lifetime of Li-ion cells. Adding one or more electrolyte additives to Li-ion batteries that act synergistically can dramatically improve the CE and long-term tests show corresponding ten-fold improvements in lifetime. (C) 2013 The Electrochemical Society.