Evaluating Fire and Smoke Risks with Lithium-Ion Cells, Modules, and Batteries

The study included characterization of the components of fire and smoke during thermal runaway for NMC and LFP cells, modules, and batteries and to determine if the size and volume of fire and smoke released scaleup linearly when one goes from the cell to module and then to a battery configuration for the same cathode chemistry. Thermal runaway tests were conducted in ambient as well as inert environments to characterize gas release with and without combustion. During thermal runaway, the test articles exhibited fire, smoke, or both. Gas analysis exhibited hydrocarbons as well as hydrogen and carbon dioxide that could accumulate above the lower flammability limit (LFL) of the gas mixture if released into an enclosure. The nature of fire and volume of smoke released do not always scale linearly with an increasing number of cells, showing that testing in the relevant configuration and environment is imperative. A good understanding of gases released into a certain enclosed space will help with safer vent and deflagration designs and provide a warning to first responders and firefighters of the expected nature of gases.