Lingmin Lin, K Pinkerton, Ofodike A. Ezekoye
Lithium-ion batteries (LIBs) undergoing thermal runaway vent a complex mixture of particles alongside condensable and non-condensable gases. These emissions may ignite or remain unignited, potentially producing a broader range of species. This study presents experimental data and physical insights into the coupled behavior of vented gases and aerosol particles emitted from cylindrical 18650-format LIBs. Thermal abuse experiments were first conducted with near-source measurements of gases and aerosol particles, providing a benchmark for condensable gas characterization. The near-source sampling configuration featured short residence times and a high air change rate. The cell thermal abuse test was then conducted in a poorly ventilated, reduced-scale room, resulting in longer gas and particle residence times. These conditions more closely represent enclosed environments such as residences or aircraft cabins and enable investigation of aerosol particle growth dynamics under confinement. In both configurations, aerosol particles smaller than 0.5 µm dominate number concentrations. Following thermal runaway, the aerosol particle number size distribution broadens, with increases in geometric mean and mode diameters. The reduced-scale room experiments reveal aerosol particle growth driven by electrolyte solvent condensation and coagulation. Notably, an increase in aerosol particle number concentration after direct cell emissions ceased is observed only in the reduced-scale room configuration. To interpret these observations, a simplified moment-based general dynamic equation model for aerosol evolution is applied to experimental data. By linking observed size distribution changes to condensation, coagulation, and sedimentation processes, this work connects fundamental battery venting mechanisms to exposure, safety, and mitigation considerations in enclosed spaces.Copyright © 2026 American Association for Aerosol Research