Lithium-Ion Battery Fire and Re-Ignition in a 2022 EV

The origin is most likely the damaged battery pack or its immediate vicinity, but the investigation must test alternatives. A collision with a concrete barrier can deform the pack, crush cells, and initiate thermal runaway; the underbody fire location and the still-warm area in the pack support that hypothesis. Re-ignition hours later is consistent with stranded energy and cascading cell failure, not necessarily a second cause. However, the fire could also have started in high-voltage cabling, a coolant line, or another underbody component, and the battery fire could be a consequence. I would examine the pack structure, cell modules, busbars, and collision deformation; review BMS data if recoverable; and compare damage on the vehicle's top and bottom. The cause should be classified as accidental due to collision damage only if the evidence shows the pack failure initiated the fire.

Before examination, the investigator should treat the vehicle as an energized electrical source. Precautions include: wearing appropriate PPE, using insulated tools, and avoiding cutting or contacting orange high-voltage cables; waiting until the pack has cooled and using thermal imaging to check for hot spots; maintaining a fire watch and keeping the vehicle at least 15–30 m from buildings, as it is here; and not storing it in a closed garage. The investigator should consult the manufacturer's emergency response guide and, if needed, a qualified high-voltage technician. During examination, avoid penetrating or disassembling the pack until it is confirmed de-energized and stable. A safety plan and communication with the fire department should be documented.

Evidence preservation is difficult because the re-ignition may destroy or alter evidence. I would document the vehicle's condition at arrival, including the re-ignition area, before moving anything; photograph and diagram the storage yard and the vehicle's position; obtain the fire department's suppression and tow records; and record the time, duration, and location of the re-ignition. I would preserve the battery pack and modules in a monitored outdoor area, use non-conductive containment if appropriate, and collect BMS or event data before power is lost. Any cells removed for analysis should be photographed in place and packaged according to laboratory guidance. The chain of custody should note the re-ignition and any evidence loss. The final report should explain how the re-ignition affected the damage patterns and why origin conclusions remain reliable or are limited.