Characterization of Lithium-Ion Battery Fire Emissions—Part 1: Chemical Composition of Fine Particles (PM_2.5)

Abstract

Lithium-ion batteries (LIB) pose a safety risk due to their high specific energy density and toxic ingredients. Fire caused by LIB thermal runaway (TR) can be catastrophic within enclosed spaces where emission ventilation or occupant evacuation is challenging or impossible. The fine smoke particles (PM2.5) produced during a fire can deposit in deep parts of the lung and trigger various adverse health effects. This study characterizes the chemical composition of PM2.5 released from TR-driven combustion of cylindrical lithium iron phosphate (LFP) and pouch-style lithium cobalt oxide (LCO) LIB cells. Emissions from cell venting and flaming combustion were measured in real time and captured by filter assemblies for subsequent analyses of organic and elemental carbon (OC and EC), elements, and water-soluble ions. The most abundant PM2.5 constituents were OC, EC, phosphate (PO43−), and fluoride (F−), contributing 7–91%, 0.2–40%, 1–44%, and 0.7–3% to the PM2.5 mass, respectively. While OC was more abundant during cell venting, EC and PO43− were more abundant when flaming combustion occurred. These freshly emitted particles were acidic. Overall, particles from LFP tests had higher OM but lower EC compared to LCO tests, consistent with the higher thermal stability of LFP cells.

Keywords

• Li-ion battery
• fire
• smoke
• toxicity
• particle emission
• chemical composition