High thermal conductive and anti-leakage composite phase change material with halloysite nanotube for battery thermal management system

The thermal safety of battery module is demonstrated as the main bottleneck to hinder wider adoption of electric vehicles (EVs). It is vital to explore efficient thermal management system to satisfy the rapidly increasing need for EVs. Composite change materials (CPCMs) as passive cooling system has greatly potential application in battery packs. However, the inherent leakage and low thermal conductivity are restricted its widely utilized in practical applications. In this study, the high thermal conductivity CPCM with PEG/EG/HNT@AP has successfully prepared through a synergistic method of in situ chemical reduction and physical blending technology. Polyethylene glycol (PEG) as the phase change matrix and halloysite nanotube (HNT) as the support material can provide cross-linked network to prevent its leakage. Especially, the expanded graphite (EG) and silver nanoparticles (AgNPs) assembled into HNT (HNT@AP) play a synergistic role to construct an interconnected thermal network. The results indicates that the thermal conductivity is increased to 1.15 W·m⁻¹·K⁻¹ and the latent heat of phase change can maintain to 103.65 J·g⁻¹, when the content of HNT@AP is 40 %. In addition, the battery module with PEG/EG/HNT@AP and PEG/EG/ER are designed and measured during charge and discharge cycling process, respectively. It reveals that battery module with PEG/EG/HNT@AP can exhibit excellent thermal management effect, which temperature was controlled below 60 °C at 3C discharge rate even under 35 °C ambient temperature. Therefore, this work sheds light on rational design of high thermal conductive composite material to improve thermal safety of battery pack in the EVs.