EV Batteries Are A Major Fire Risk And Carmakers Need To Act

Electric Vehicles / Comments

A few manufacturers are helping, most are not.

In 2018 there were about 181,500 highway vehicle fires, according to the National Fire Protection Association. The vast majority of those were gasoline and diesel-powered vehicles. For whatever reason, we expect and accept that. But with EV fires it's different.

The National Traffic Safety Board addressed these EV fires in January with a report noting that there are two main safety issues. First, the inadequacy of vehicle manufacturers' emergency response guides, and the gaps in safety standards and research related to high-voltage lithium-ion batteries involved in high-sped, high-severity crashes.

Additionally, EVs pose a risk of electric shock to emergency responders, and then there's the thermal runaway problem. That is a process that is accelerated by increased temperatures, in turn releasing energy that further increase temperature. It's an uncontrolled positive feedback loop.

Tesla
Tesla
Tesla
Tesla

The Tesla fire over the weekend exemplifies this problem. In that incident there were actually several problems. The first being that no one was in the driver's seat as the owner was probably showing off Tesla's Autopilot system that is NOT a hands-free system. There was a crash into a tree and the resulting fire took hours and 30,000 gallons of water to keep the battery from reigniting.

The problem with EV lithium-ion batteries is the chemistry, which is different from earlier nickel-metal hydride hybrid batteries. In the new batteries, which also power your laptop, smartphone, and a ton of other stuff, the solution consists of an organic solvent and inorganic salt, according to the International Association for Fire Safety Science. The most widely used is called lithium hexafluorophosphate, which has poor thermal stability even at moderate temperatures (60-85-degrees Celcius).

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The irony is that the reaction creates more oxygen, which creates more fire, which creates more heat, which creates more oxygen until firefighters have emptied a swimming pool's worth of water on the burning vehicle.

Tesla is far from the only automaker with this issue. A quick search reveals that almost every EV has experienced this, and many automakers have issued recalls because of it. In September, BMW initiated a recall in the US because of a risk of fire caused by debris that may have gotten into battery cells during manufacturing. In early October, the National Highway Traffic Safety Administration opened an investigation into reports of apparently spontaneous battery fires in Chevrolet Bolt EVs. Hyundai had one for the Kona, bringing back over 80,000 vehicles worldwide.

A few manufacturers haven't been standing on their heels for this. General Motors, Nissan and Tesla have all published guides for first responders on how to correctly handle a crashed electric vehicle.

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Interior Overview Hyundai

Nissan has a heading for each one of its vehicles, posted on the National Fire Protection Association training and events resources page. Each Leaf has its own file, as does its selection of Altima, Pathfinder and Rogue Hybrids. For the most recent Leaf, Nissan diagrams all the systems, noting which parts are high voltage and what specific labels mean. It also explains where the master shutoffs are and what sort of personal protection to use.

Chevrolet has about 20 entries, ranging from its dual fuel cars to its EVs, the most recent being the Bolt EV and the Silverado Hybrid. It notes what points firefighters can cut, where everything is located, and what to do in case of fire.

The document says that "a battery on fire will not explode. If battery cells reach high enough temperature, they vent and release electrolyte. Battery electrolyte is flammable. Use copious amounts of water to cool the battery to extinguish the fire. Do not use an ABC dry chemical extinguisher because it will not extinguish a battery fire."

Nissan
Nissan
Nissan
Nissan

Findings from the NTSB report note that instruction in most manufacturers' emergency response guides lack necessary, vehicle-specific details on suppressing the fires. It also says that stranded energy, the energy remaining in a damaged high-voltage lithium-ion battery, poses both a risk of shock and battery reignition. That leads to it recommending that damaged EVs should be stored within a 50-foot clear radius area. Finally, it says that "when determining a vehicle's US New Car Assessment Program score, factor in the availability of a manufacturer's emergency response guide and its adherence to International Organization for Standardization."

NCAP is a consumer information program for evaluating vehicle safety performance. The program tests vehicle performance in various crash scenarios and provides an objective rating on a 5-star scale to clearly inform consumers of a vehicle's safety performance. If the manufacturer has better documentation, it will get a better score.

Hyundai

We can all agree that EVs are good for the planet, and getting better as the processes are becoming cleaner using less poisonous materials. The energy coming out of our plugs is cleaner too. And now that us enthusiasts can get in on the fun with performance-oriented EVs, all the better. The main problem here seems to be the lack of information, both for the consumers and the first responders. When that improves, battery fires will still make news, but hopefully they won't take any people or property with them.

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