Degradation at Different Temperatures of Cycle Aging in BEV Lithium Batteries Subjected to Fast-Charge

Understanding and predicting the degradation of lithium batteries under various operational conditions remains a critical challenge for both mobile and stationary applications. Batteries ageing phenomena are deeply influenced by a multitude of operational variables and furthermore, ageing itself implies two distinct phenomena: energy degradation and power degradation which exhibit non-monotonic and non-linear behaviour, generally unrelated. For these reasons, algorithms aimed at estimating and predicting the ageing level of these devices consistently require precise datasets from experimental ageing campaigns. This work presents an experimental ageing campaign conducted on NMC-type lithium batteries used for automotive applications and subjected to fast-charging. Gathered data allow to identify degradation in terms of both energy and power, following realistic cycle ageing at two different temperatures. The results show that, from 0 to 1000 cycles, energy degradation may appear similar between cycling at 20° C and 40° C, while power degradation is significantly higher at <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">${4 0}^{\circ} \mathrm{C}$</tex>.