A thermo-mechanical-chemical composite barrier for suppressing thermal runaway propagation in NCM811 battery module

Abstract

High-nickel cathode lithium-ion batteries have gained widespread use in electric vehicles. However, the thermal safety risks associated with battery failure remain a significant challenge. Conventional thermal insulation materials have proven suboptimal in preventing thermal runaway propagation among high-specific-energy battery module. Thermal runaway of these cells can result in temperatures exceeding 1000 °C, leading to combustion when the fire triangle conditions are met. This makes it difficult to guarantee system-wide thermal safety through insulation alone. This paper introduces a composite material primarily composed of porous fiber and high enthalpy phase-change materials, specifically designed as a protective barrier positioned between adjacent cells, functioning as a passive safety measure. This composite material exhibits a tri-stage temperature-responsive behavior characterized by thermal control, dissipation, and insulation, thereby achieving effective thermal regulation. In addition, it demonstrates thermo-mechanical-chemical responsiveness, making it particularly well-suited for application in high-energy-density battery modules. With a compact thickness of only 2.5 mm, the material effectively prevents thermal runaway propagation and combustion in NCM811 battery modules, while also providing structural reinforcement, thermal mitigation, and flame suppression. Compared to conventional insulation materials, this innovative barrier delivers significantly enhanced performance in both safety and multifunctionality.