Numerical optimization for a phase change material based lithium-ion battery thermal management system

The phase change material (PCM), as a passive and high latent heat material, is usually used in the passive battery thermal management system (BTMS). However, to achieve efficient and compact battery thermal management system, the property of phase change material needs to be optimized. In this study, phase change material, composed of expanded graphite and paraffin waxes with various melting points, was adopted to explore the effect of composite phase change material 's various phase transition temperature on battery thermal management performance. It was found that the paraffin wax with a transition temperature of 48 degrees C is the most suitable. In addition, a multi-parameter electrochemical-thermal coupling optimization model was developed to optimise the efficiency of phase change material to determine the battery spacing, convective heat transfer coefficient and expanded graphite mass fraction. The optimization results show that using parameters with a battery interval of 4.4 mm, a convective heat transfer coefficient of 0.8 W/m2/K, and a mass fraction of 10.9 % can not only satisfy the thermal safety requirement but also reduce the volume fraction of phase change material by 18.4 %.