Transient heat transfer studies of aluminium graphene nanocomposite heat spreaders using digital interferometry

Abstract

The thermal runaway caused by poor thermal management of batteries is one of the main challenges being faced by electric vehicles (EVs). An energy-saving, passive method for efficient thermal management of two and three wheeler battery packs is the use of aluminum (Al) heat spreaders with superior thermal conductivity, in conjunction with natural air cooling. Thermal conductivity of the (Al) heat spreaders can be enhanced by incorporation of graphene flakes. The present work focuses on extensive heat transfer studies of Al graphene nanocomposite (AGNC) heat spreaders with enhanced heat transfer capability. Few layered graphene (FLG) was synthesized by the liquid phase exfoliation method and characterized by X-Ray diffraction (XRD) analysis, Transmission electron microscopy (TEM), and Confocal Raman spectroscopy. AGNC heat spreaders were made by powder metallurgy. Mach-Zehnder interferometric (MZI) technique was employed to analyse the heat dissipation characteristics of AGNC heat spreaders, which infact is the novelty here. The slope of the local heat flux curve obtained by MZI was found to be less in the case of AGNC heat spreaders as compared to Al heat spreader indicating more uniform heat dissipation for AGNC heat spreaders. Transient heat transfer studies showed 63 % enhancement in the heat dissipation for AGNC heat spreader as compared to pure Al heat spreader. The transient temperature distribution was also visualized using Infrared (IR) thermography and the results show more uniform temperature distribution in the case of AGNC heat spreaders. The better phonon transport across the grain boundaries loaded with FLGs could be the reason for faster heat transport in AGNC heat spreaders.