Why Electric Cars Are Catching Fire in Floods

If you own an EV or are considering buying one, the question of whether electric vehicles can catch fire is crucial, and unfortunately, the answer is yes. What’s even more unsettling is that it can happen when the vehicle is submerged in floodwaters, as evidenced by a video posted on USA Today in the aftermath of Hurricane Helene.

“It’s not surprising,” said the contractor who is currently wiring a new backup generator at my house. “When you short-circuit a battery that operates at 300 to 400 volts, you’re going to generate some serious sparks.” If you’ve ever shorted out a conventional 12-volt car battery, you’ve seen serious sparking. Now, multiply the voltage by a factor of 30, and you get the idea. That kind of energy, especially if sustained, can cause massive electrical arcing and extensive damage.

To get some perspective on this issue, I spoke with Jason Fladhammer from Batteries Plus.

Can Electric Cars Catch Fire?

Besides the incident reported by USA Today, there have been several reports of EVs catching fire. On Aug. 21, for instance, the National Transportation Safety Board announced it was investigating a fire after a Tesla truck collided with a tree on Highway 80 near Sacramento, CA. A few weeks before that, The Japan Times reported that an unplugged Mercedes-Benz sedan exploded and caught fire in an underground car park in Seoul, South Korea, forcing the evacuation of 700 residents from the apartment complex above it.

The phenomenon of lithium batteries catching fire is nothing new. It can even happen to cell phone batteries when they overheat, but an EV battery is much bigger and can obviously cause much more damage. So if you’re still wondering: “Can electric vehicles catch fire?” wonder no more. The surprising plot twist is that it can happen underwater.

Why Are Electric Cars Catching Fire in Floods?

According to Fladhammer, batteries don’t ignite because of the water itself, but deposits in the waterprimarily saltthat turn it into an electrolyte. An electrolyte is an ion-rich solution that can conduct electricity.

“Saltwater is considered extremely conductive due to the dissolved ions it contains,” says Fladhammer. “When it comes into contact with a battery, especially a lithium-ion battery, it can create unintended channels for electricity to flow, which often leads to short circuits within the battery cells. This generates heat, and if that heat builds up too much, it can trigger a thermal runaway, which can potentially cause the battery to catch fire or even explode. The saltwater speeds up this whole process by acting as an efficient conductor for electrical currents to move in ways the battery isn’t built to handle.”

According to a2024 study published in Science Direct, even salt spray can cause an EV battery to self-ignite, with the likelihood of ignition increasing with exposure time to the spray and the age of the vehicle. Salt spray is an electrolyte butalso highly corrosive and can damage the individual cells inside the battery. The resultant short circuits generate heat that can quickly spread throughout the battery.

Tips to Prevent My Electric Vehicle from Catching Fire in Extreme Weather

In the event of a flood or a flood forecast, Fladhammer recommends doing the following:

• Move the vehicle to higher ground, if possible.
• Ensure the car is turned off and unplugged from any charging sources.
• Protect the car with a waterproof cover, preferably one supplied by the manufacturer to fit your vehicle.

If your EV does become submerged in saltwater, Fladhammer recommends having it checked out at a dealership or ASE Certified repair facility after the water recedes. He says this is primarily “to clean any salt and or corrosion off of the battery terminals.” Salt is corrosive, and the longer it’s in contact with the battery, the higher the likelihood of a fire occurring at some time in the future when you least expect it.

About the Expert

• Jason Fladhammer is the Director of Quality Assurance at Batteries Plus, a nationwide battery outlet that has been in operation since 1988.

Sources

• USA Today: Video captures Tesla Vehicle Bursting into Flames as Hurricane Helene Floods Florida Garage; October 2024.
• X: @NTSB_Newsroom; August 2024.
• The Japan Times: Seoul EV Explosion Sparks Safety Fears, Prompting Charging Rethink; August 2024.
• PC Mag: Why Phones Explode, and How to Prevent It From Happening to You; September 2024.
• ScienceDirect: The Electro-Thermal Behaviors of the Lithium-Ion Batteries Corroded by the Salt Spray Environment: February 2024.

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