The National Transportation Safety Board (NTSB) says that the guidelines electric vehicle manufacturers have established for dealing with battery fires are inadequate. Furthermore, industry research and safety standards regarding high-voltage lithium ion battery fires has significant gaps, the agency says, especially when it comes to high-speed crashes.
The NTSB has no authority to order carmakers to make changes. It is therefore asking them to create vehicle-specific response guides for how to fight battery fires and limit the chance of reignition. It also wants owners to get information on how to safely store a vehicle with a damaged lithium ion battery.
High-voltage lithium ion batteries allow electric vehicles to go for long distances on cleaner fuel (electricity). However, they can melt down in what is called “thermal runaway.” This is a chemical reaction that puts the battery into an uncontrolled increase of temperature and pressure. Thermal runaway can cause a fire that is harder to put out than a gasoline fire.
Fires in lithium ion batteries can also reignite. There are ways to reduce the risk, and the NTSB wants first responders to have easy access to those techniques.
According to the Associated Press, the NTSB has been investigating battery fires since 2017 and 2018. In at least three cases, the battery reignited after the fire was thought to be extinguished. The three cases involved Tesla vehicles.
“The risks of electric shock and battery reignition/fire arise from the ‘stranded’ energy that remains in a damaged battery,” says the agency.
First responders may not know how to put out the fire effectively
In one crash investigated by the NTSB, a Tesla Model X exited the roadway and crashed at high speed into a residential garage. Firefighters pointlessly poured thousands of gallons of water onto the roof of the vehicle, not realizing they needed to direct the water onto the battery compartment.
One way to prevent reignition is to remove the battery from the engine and store it in a saltwater bath. This discharges the remaining energy in the battery.
The National Fire Protection Association, which provides training to first responders, says that has already trained around 250,000 first responders on how to put out lithium ion battery fires and limit the risk of reignition. However, there are about 1.2 million firefighters in the U.S. alone.
The NTSB has also called upon the National Highway Traffic Safety Administration (NHTSA) to consider the availability of a vehicle-specific response guide when it calculates vehicle safety reviews. For its part, NHTSA has begun a fire safety initiative around electric vehicle batteries after growing concerns about vehicle and structure fires related to these batteries.
The automotive trade group Alliance for Automotive Innovation plans to review the NTSB’s recommendations and work with NHTSA, fire associations, automotive engineers and others to improve the safety of lithium ion batteries.
If your vehicle catches on fire, the best thing you can do is get all occupants out of the vehicle as soon as possible. Turn off the engine to reduce the flow of fuel and leave the hood closed so air doesn’t come in to fan the flames. Call 911 and wait at least 100 feet from the vehicle.
If you suspect a product defect may have caused the battery fire, discuss your concerns with an attorney who handles product liability.