Battery thermal modelling - Assessment of heat distribution and optimization of battery design concept

The goal of this study was to conduct a model based, thermal analysis, of a large cylindrical LFP Lithium-iron Phosphate, lithium-ion battery cell. At the end, the electrochemical-thermal type of model, developed in this study, succeeded, in both determining the temperature of the cell that was previously measured experimentally; as well as predicting an overview of the temperature distribution, occuring inside the cell with a deviation from the experimental values of only 5% in order of magnitude. For this purpose, a wide range of different operating conditions, and loading cycles have been applied to the cell, which were also simulated numerically. The results then first obtained, could clearly demonstrate the importance of the increase of the temperature of the cell, caused by the increase of the current rate, observed for both surface and core regions. Moreover, for an optimization of the battery design concept, a second improved model, involving a 2D modelling of the internal layered configuration of a cross section of the cell, was developed as well. By comparing the results from this last cross sectional model, with those belonging to the first achieved lumped thermal model of the cell, a better understanding and visualization of the internal temperature distribution, could be reached for the first time for such type of large format battery cell. Principally, the comparison of the models, stressed the existing influence, of the way to model the internal cell configuration, on the temperature distribution occuring inside the cell, and on its associated temperature values obtained for both surface and core regions.