EV Fires
Courtesy of Automotive News, Oct 14 2024 Edition:
Here’s why saltwater flooding can lead to EV battery fires
Florida has seen at least 16 lithium ion battery fires in the wake of Hurricane Helene, six associated with electric vehicles.
While electric vehicle battery fires remain exceedingly rare, saltwater exposure from Hurricane Helene-type storm surges make them more likely.
Florida has seen at least 16 lithium ion battery fires in the wake of the storm, six associated with EVs, said Jimmy Patronis, the state’s CFO and fire marshal. One much-watched video circulating shows a Tesla in a Siesta Key garage that caught fire because of saltwater exposure from the storm.
“Unfortunately, prior to Hurricane Helene making landfall, we did not see a lot of proactive measures by manufacturers in notifying customers in storm surge areas to relocate their vehicles,” Patronis said in a statement. “It’s not too late for these manufacturers to send out notifications and fire safety information directly to their consumers.”
To be sure, fires occur in internal combustion engine vehicles much more often. EVs in the U.S. caught fire at a rate of 25 per 100,000 sold, compared with 1,530 for gasoline-powered vehicles and 3,475 for hybrids, according to a study conducted by insurance company AutoInsuranceEZ using data from the National Transportation Safety Board.
Nonetheless, battery fires — including fires from micromobility products such as e-bikes — remain a stubborn public relations problem for EVs. Damage, overuse and incompatible parts can lead to explosive fires that burn for days and take tens of thousands of gallons to extinguish. The problem goes beyond appearances — lithium ion battery fires have killed three people in New York City this year as of Sept. 30.
Water exposure can increase the risk of fires. The stability of a lithium ion battery system relies on the controlled movement of ions across a separator in the battery. Water is electrically conductive.
When water gets into the battery, ions are able to take a shortcut across the separator and move in an uncontrolled way through the battery system. This generates self-sustaining heat that can boil the electrolyte fluid in the battery, causing a lot of pressure and potentially igniting a fire.
Salt water exacerbates the problem. Salt makes the water more conductive, providing an even quicker and easier way for ions to move chaotically across the system.
Salt water can mimic “the salts found in a battery cell’s electrolyte,” said Conrad Layson, senior analyst for alternative propulsion at AutoForecast Solutions. “When one cell ignites, it affects the other cells around it. They ignite in sympathy, and the cascading effect will ignite the pack.”
Florida is advising EV owners impacted by the hurricane to leave vehicle windows and doors open to vent gases, move vehicles to open-air locations, and disable vehicles and wait to charge them until they are confirmed to be safe.
