Numerical investigation of battery thermal management by using helical fin and composite phase change material

Li-ion batteries have become an indispensable part of modern life thanks to their portability, energy density, fast charge-discharge capability and various application areas. The thermal performance of the PCM promising method for battery thermal management systems (BTMS) is limited due to weak thermal conductivity property. The aim of this study is to investigate the contribution to the performance of BTMS by using innovative helical fins to improve the heat transfer performance of PCM due to its low thermal conductivity. Besides, the study includes composite phase change material (CPCM) due to advantages in practice such as form stability, mechanical behavior and higher thermal conductivity compared to PCM. In this scope, a hybrid system including helical fin and CPCM, paraffin-based expanded graphite (EG), is numerically investigated to ensure thermal control of a Li-ion battery in this study. Results shows that safe operating time is prolonged by increasing the widths and the number of rounds of the helical fin. However, the contribution of the EG fractions on the BTMS is ordered as an EG fraction of 12 % > 6 % > 20 % > 0 % due to a balance between the thermal conductivity and the latent heat property. The longest safe operating time is obtained by using Fin_W6-NR3 for EG fraction of 12 % in the CPCM as 9316 s corresponding to 244.0 % higher than the case of EG = 0 % and no fin used.