Improving thermal performance of the battery module by hybrid system of composite phase change material combined with liquid cooling device

摘要

Lithium-ion batteries are widely used in pure/hybrid electric vehicles nowadays. Effective heat dissipation is significant for the battery module. A better battery thermal management system (BTMS) is urgently needed to rein heat balance inside the battery module which can also minimize the risk of thermal runaway and rise the efficiency. The hybrid BTMS of this study used composite phase change material (CPCM) which was composed by paraffin wax, expanded graphite of different expansion coefficients, epoxy resin, and flame retardant. Moreover, the system also combined with a liquid cooling circulation device. The coolant was the mixture of ethylene glycol and water. The cooling tube was divided into a wavy type and a flat type channel for comparison the cooling efficiency. The results showed that the added 6% expanded graphite can effectively increase the thermal conductivity of CPCM. In addition, flash point and self-extinguishing time results indicated phosphorus flame retardant could effectively improve the thermal resistance of CPCM structure while under reasonable filled ratio. The battery module combined with CPCM and the wavy type channel liquid cooling circulation device could establish battery module temperature into evenly distribution.