Analysis of the improvement of a lithium-ion battery module cooling system employing nanofluid and nano encapsulated phase change materials by means of a lumped electro-thermal model

Abstract

In this study an analysis of the employment of nanoparticles and nano encapsulated phase change materials for battery cooling is provided. By using a previously validated electro-thermal model of a lithium-ion battery module, the effect of 5 different nanoparticles and 6 different nano encapsulated phase change materials is estimated. The analysis is provided for a battery module charge process at 4C, with a coolant mass flow of 2 l/min and with ambient and fluid temperature equal to 20 °C. The concentration of the nanofluid is varied between 0.01 % and 5 %. By increasing the concentration, a beneficial effect is observed on the battery cooling, in terms of maximum temperature achieved during the charge process and heat dissipated into the coolant. Among the 30 different combinations of nanoparticles and nano encapsulated phase change materials analyzed in this work, it is concluded that the best results in terms of dissipated heat and maximum temperature are obtained for copper oxide (CuO) combined with octadecane. In this case, at 20 °C, a reduction of the maximum temperature of about 2 °C is obtained with a volume fraction equal to 5 %, with respect to the case in which there are no nanoparticles. Furthermore, the total heat dissipated in the coolant is increased by 28 %. Finally, the study proposes a design of experiment to evaluate the performance of a phase change material for battery cooling. For this analysis, 4 variables are considered (concentration, melting temperature, heat of fusion and characteristic temperature range) and the effect on the maximum temperature and on the temperature spatial difference is observed: it is found that the thermal evolution of the cells is mostly affected by melting temperature and concentration.