Impact of the Temperature in the Evaluation of Battery Performances During Long-Term Cycling—Characterisation and Modelling

This paper presents the results regarding the thermal characterisation and modelling of
high energy lithium-ion battery cells at both room (25 C) and cycling (35 C) temperatures. In this
work two types of Nickel Manganese Cobalt (NMC) batteries are studied: a fresh (or uncycled) and
an aged (or cycled) battery cells. The ageing of the studied NMC battery cells is achieved by means
of accelerated ageing tests (i.e., repetition of numerous charge and discharge cycles) at 35 C cycling
temperature. Temperature at the surface of the battery cells is characterised, with a set of three
discharge current rates 0.3C (i.e., 6 A), 1C (i.e., 20 A) and 2C (i.e., 40 A), and the evolutions at three
different locations on the surface of the battery cells namely, at the top, in the center and at the bottom
regions are measured. In addition, temperature and ageing dependent electrochemical-thermal
modelling of the uncycled and cycled battery cells is also successfully accomplished in case of both
room and cycling temperatures. Numerical simulations were carried out in case of high 2C constant
current rate, and the assessment of the modelling accuracy by comparison of the predicted battery
cells voltage and temperature with respect to the experimental data is further presented. With this
paper, thermal performances of battery cells prior and after long-term cycling are evaluated at the
cycling temperature, next to the ambient temperature. Hence, thermal characterisation and modelling
results are more closely reflecting that encountered by the battery cells in real cycling conditions,
so that their performances are believed in this way to be more objectively evaluated.