Synergy of high-efficiency passive protective nanocomposite materials and active liquid cooling for suppressing thermal diffusion in lithium-ion power batteries

• A novel low-cost, high-performance battery insulating material has been developed. • Merely 3 mm of composite successfully prevented thermal runaway propagation in NCM 811 battery modules. • The synergistic effect of the prepared insulation and the optimised liquid cooling showed better performance in terms of TRP mitigation. The widespread adoption of high-energy-density NCM 811 lithium-ion batteries in electric vehicles is hampered by significant safety risks associated with thermal runaway and its propagation. This study addresses this critical issue by developing and validating a hybrid thermal management strategy that synergistically combines passive insulation with active liquid cooling. A fiber-reinforced fumed silica composite was fabricated via hot-pressing and subsequently encapsulated into vacuum insulation panels. This material exhibited an ultralow thermal conductivity of 4.42 mW/(m·K) and demonstrated exceptional flame retardancy and thermal stability in flame burn and hot plate tests. Numerical simulations revealed that a mere 3 mm thickness of this composite could completely block TRP within an NCM 811 battery module. Furthermore, the conventional single-serpentine liquid cooling plate was optimized into dual-inlet and quadruple-inlet configurations. Simulation results demonstrated that the hybrid system, integrating the 3 mm composite with the optimized quadruple-inlet cooling plate, successfully suppressed thermal runaway propagation and limited the peak temperature of adjacent cells to 162 °C. This work provides a practical and highly effective solution for enhancing the safety of high-energy battery systems, thereby contributing to the development of more reliable electric vehicles.