Liquid cooling system for battery modules with boron nitride based thermal conductivity silicone grease

Abstract

Heat-conductive silicone grease (HCSG), one of the most common composite thermal interface materials (TIMs) used in many advanced applications, is limited by its low thermal conductivity (TC). Different surface modification agents are required to improve the dispersion of TC additives and the interfacial compatibility with the silicone matrix. In this study, MQ silicone resin (MQ) was used to modify two kinds of self-made spherical boron nitrides (SBNs), with different particle sizes, using the sedimentation method. The amount of filler content allowed within the SBNs increased owing to the similar polarity of the MQ and the silicone matrix, and a HCSG with a TC of 1.22 W (m⁻¹ K⁻¹) and a thermal resistance (TR) of 0.49 °C W⁻¹ was obtained, respectively. In addition, the TC pathway was formed more easily with the 15 μm SBNs than with the 5 μm SBNs. In order to verify its potential application in battery thermal management, the HCSG was assembled on the surface of the liquid-cooling plate in the 18 650-battery module, and it was found that the maximum temperature of the battery module could be maintained below 42 °C, and the temperature difference could be controlled within 5 °C. Thus, with these excellent performances, the MQ silicone resin reported here, with respect to the assembly methods, will provide insights into the thermal management and energy storage fields.