Thermal conductive network construction and enhanced thermal conductivity in mica tape composites for large generator insulation

The rapid development of large generators to high voltage and large capacity calls for high thermal conductivity and excellent insulation for their insulation. In this work, an hexagonal boron nitride (h-BN) thermal conductive network is firstly constructed. The thermal conductivity network in mica paper exhibits a three-dimensional structure, and mica tape composites was prepared with glass fabric, epoxy and mica paper above. Accordingly, a typical mica paper and mica tape have thermal conductivities of 1.07 W/(m·K) and 0.416 W/(m·K), respectively, which are 157.21% and 75.53% higher than those without filling. A modified thermal conductivity model (LN-SSS model) is proposed to analyze the thermal conductivity of the mica tape composites, which is found to fit the mica tape's experiment value and tendency accurately, and the mica tape composites have excellent insulation properties. The design approach in this paper also provides new ideas for insulating materials and structures with high thermal conductivity.