Bidirectionally High Thermal Conductive Phase Change Materials with Arrayed Radially Oriented Boron Nitride Nanosheets for Battery Pack Thermal Management

Composite phase change materials (PCMs) consisting of thermally conductive nanofillers and a PCM matrix can provide an effective buffer for battery packs to avoid thermal runaway. However, there remain some challenges to overcome the trade-off between thermal conductivity and phase change enthalpy. Herein, we developed a bidirectionally high thermal conductive composite PCM featuring a radially oriented structure using an arrayed radial freezing method. The advanced composite PCM achieves high radial (6.09 W m(-1) K-1) and axial thermal conductivities (4.83 W m(-1) K-1) while maintaining high phase transition enthalpy (146.7 J g(-1)), outperforming most reported composite PCMs. Incorporating this composite PCM into a battery pack lowers the battery surface temperature by at least 10 degrees C and significantly reduces the temperature difference within the battery pack from 6.7 to 1.3 degrees C. Our approach is versatile with various thermally conductive nanofillers, providing opportunities for developing next-generation battery thermal management materials.