Thermal Analysis of Liquid-Cooled Battery Pack with Cell-to-Cell Parameter Variation

This paper deals with the analysis of cell-to-cell parameter variation influence on battery pack temperature distribution for automotive applications. A 2D experimentally validated lumped parameter model of a P5S5 lithium-ion battery pack based on Nickel-Manganese-Cobalt cell technology has been developed in the Matlab environment, considering the electrical and thermal domains of the system. Through numerical simulations, the cell-to-cell parameter variation has been studied taking into account the battery cells' variability in terms of cell parameters. Furthermore, a liquid Battery Thermal Management System has been implemented in the considered battery pack architecture for the evaluation of the impact of a cooling system on the temperature distribution. Results achieved suggest that the battery pack variability influences the thermal distribution and changes dynamically the hotspot position in the battery pack through the variation of battery cell resistance and current values. In addition, the variability of the cell parameters increases during the pack operation due to the uneven thermal distribution and current unbalances. However, the liquid cooling system can handle the thermal variability for a small-size battery pack and reduces the evolution of the parameters variation by about 33 %.