Electric cars may be safer than combustion-engined vehicles regarding the risk of fires, but they are notoriously more difficult to fight. Lithium-ion batteries frequently reignite. According to NTSB (National Transportation Safety Board), ERG (Emergency Response Guides) from electric car manufacturers do not help because they lack clear information about extinguishing these fires.
This is the conclusion of NTSB’s Safety Report 20/01, which investigated four fires involving electric vehicles, all of them made by Tesla. The first was with a 2016 Tesla Model X that crashed in Lake Forest, California, after going 82 mph in an area limited to 35 mph on August 25, 2017. The driver was seriously hurt, and the passenger had minor injuries.
The second crash was on March 23, 2018. It involved a 2017 Tesla Model X, which crashed at 71 mph. The driver died due to injuries sustained in the crash. The third happened in Fort Lauderdale on May 8, 2018. Again, it was caused by excess speed: 116 mph in a zone limited to 30 mph. The 2014 Tesla Model S could not prevent the driver and front passenger deaths. A rear passenger suffered serious injuries.
The last fire happened spontaneously on June 15, 2018. A 2012 Tesla Model S was just cruising in an urban area in West Hollywood, Los Angeles, when other drivers warned about smoke in the car. The driver left the car without getting hurt. It was similar to what happened to Usmaan Ahmad in Frisco last November 24.
The report goes on, analyzing other fires on a Chevrolet Volt, a BMW i3, a Mitsubishi Outlander PHEV, and a BMW i8. It also discusses the legal requirements electric cars have to respect and how ERGs must meet ISO 17840. The question is if they do so.
To answer that and some other relevant issues, such as if the ERGs contain elements in the NFPA guide for their respective vehicles, NTSB analyzed the Emergency Response Guides from 36 vehicles (Mercedes-Benz has only one for all its cars).
The board concluded that only 2 among these 36 vehicles have specific instructions for fires in the battery pack – or high-voltage battery, as NTSB prefers to call it. They are the 2018 Mitsubishi Outlander PHEV and the Proterra Catalyst E2 EV Bus.
It could be worse: none of the 36 cars had information on mitigating risks of stranded energy, which causes cells to reignite. Many also lack information about dealing with a submerged vehicle, post-incident recovery or towing a damaged EV, and storing a damaged electric car.
The worst ERGs come from the VW e-Golf (from 2014 up to 2018), 2018 Volvo XC60 PHEV, Van Hool Bus, and Smith Newton Step Van (from 2012 up to 2017). Of the eleven questions NTSB made about their Emergency Response Guides, they were only compliant with one.
This result made the board urge for improvements on ERGs for electric vehicles. Apart from asking them to follow the “ISO standard 17840, as included in SAE recommended practice J2990,” NTSB asked electric car manufacturers to add to these guides information on:
“(1) fighting high-voltage lithium-ion battery fires;
(2) mitigating thermal runaway and the risk of high-voltage lithium-ion battery reignition;
(3) mitigating the risks associated with stranded energy in high-voltage lithium-ion batteries, both during the initial emergency response and before moving a damaged electric vehicle from the scene; and
(4) safely storing an electric vehicle that has a damaged high-voltage lithium-ion battery.”
The analysis of the Tesla accidents revealed to NTSB issues related to all four of these requirements. The Safety Report 20/01 is available online for those who would like to learn more about these fire situations.
For the safety not only of first responders but also of the car occupants and people nearby, NTSB’s recommendations seem to be those that require very little effort for massive benefits. Getting this sorted is probably easier than an over-the-air update.