Heat dissipation performance research of battery modules based on composite phase change materials cooling and electrochemical thermal coupling model

Abstract

In order to improve electric vehicle lithium-ion batteries (LIBs) performance and increase cycle life, it is crucial to design a reliable and efficient battery thermal management system (BTMS). Compared with other active battery cooling methods, passive phase change material (PCM) cooling has the advantages of simple structure, good temperature control uniformity, strong reliability, and no additional energy consumption. This article uses a series of experimental procedures to add expanded graphite to traditional paraffin wax PCM and obtain composite phase change materials (CPCM) with different mixing ratios. A control experiment is created to compare the cooling performance of the CPCM cooling with natural convection cooling, research shows that the cooling performance of CPCM can well meet the cooling demand which maximum temperature and maximum temperature difference of battery modules. In addition, to study the performance of thermal properties parameters related to CPCM, a COMSOL numerical calculation model of battery module based on CPCM cooling and electrochemical thermal coupling model is established. The effectiveness and accuracy of the model are verified through heat generation experiments at different rates (0.5 C, 1 C, 1.5 C), with a maximum temperature error of 1.6 K and an error accuracy of less than 0.6%. Subsequently, the performance of phase change temperature, thermal conductivity and phase change latent heat is studied and reasonable value ranges are obtained, which are 312 K∼318 K, 2.5 W /(m·K), and 175 J/g∼200 J/g, respectively.