Chemical composition and toxicological properties of particulate emissions from lithium-ion battery fires

This study assessed the physical, chemical, and toxicological properties of particulate emissions produced from lithium-ion battery fires. Commercially-available nickel manganese cobalt (NMC) battery modules were overcharged to trigger thermal runaway. The first experiment allowed the battery modules to burn without engaging any suppression system, while two additional experiments were performed with water and a potassium-based aerosol to suppress the battery fires. Results showed the formation of large diameter particles with geometric mean diameters of ∼360 nm, with their majority be below 1 μm. Depending on the experimental conditions, particle morphology revealed the generation of more spherical complex particles, while particle composition showed a mix of organic and inorganic agglomerates. Particle metallic composition was dominated by Li, Ni, Mn, Co, O, and Al, consistent with the chemistry of the battery modules. Medium and high molecular weight polycyclic aromatic hydrocarbons (PAHs) showed higher concentrations than lighter PAHs. Small-chain perfluoroalkyl and polyfluoroalkyl substances (PFAS) dominated the particle emissions, with the presence of legacy PFAS suggesting that these compounds are still used in the manufacturing of lithium-ion batteries. All particle samples induced elevated oxidative stress and inflammatory responses, and correlation analysis identified relationships between particle composition and toxicological outcomes.