(Invited) Culprits or Collateral Damage? The Science behind Lithium-Ion Battery Failure Investigations

Abstract

Thermal runaway failures of lithium-ion batteries have garnered a great deal of attention in recent years, including notable failures in the spaces of consumer products, electric vehicles, and energy storage systems. The growing public awareness of hazards associated with thermal runaway in lithium-ion batteries has coincided with increased scrutiny of lithium-ion batteries when they are found at fire scenes. Lithium-ion batteries can go into thermal runaway due to heating from an external fire, even if they are not the cause of the fire. As always, the fire investigator and other experts involved in the failure analysis need to remain guided by the scientific method when performing an origin and cause analysis, including when that analysis involves lithium-ion batteries.This presentation will encompass many of the tools and reasoning that may be relied upon when analyzing the role lithium-ion batteries at fire scenes, as well as in the post-scene analysis of batteries and battery-containing devices. Techniques for understanding heat release and heat release rate during thermal runaway failures will be discussed, as well as the associated literature that may be relied upon to estimate heat release based on chemistry and capacity of the cells in question. Also to be discussed are metallurgical approaches and techniques that may inform the conditions that likely existed during the failure of the battery.