In a perfect world, no one would ever die or be injured in an electric vehicle accident. But in the real world, bad things happen to good people. Tesla has experienced some bumps and bruises lately, as a few of its automobiles have run into things they aren’t supposed to, like parked fire trucks and highway barriers. Just this week, two teenagers riding in a 2014 Model S in Florida were killed when the car left the road and slammed into a concrete barrier.
Police say speed seems to have been a factor in that tragedy, but few details are known at this time. What is known is the car burst into flames shortly after the accident, prompting more concerns about battery fires in electric vehicles and whether first responders are adequately trained in how to deal with them. The National Transportation Safety Board is sending a team to Florida to examine that issue, according to CNN.
The NTSB investigation will “primarily focus on emergency response in relation to the electric vehicle battery fire, including fire department activities and towing operations,” the agency says. According to NTSB chairman Robert Sumwalt, the “NTSB has a long history of investigating emerging transportation technologies, such as lithium-ion battery fires in commercial aviation, as well as a fire involving the lithium ion battery in a Chevrolet Volt. The goal of these investigations is to understand the impact of these emerging transportation technologies when they are part of a transportation accident.”
In a statement, Tesla says, “We have not yet been able to retrieve the logs from the vehicle, but everything we have seen thus far indicates a very high speed collision and that Autopilot was not engaged.” The NTSB confirms that Autopilot is not part of its investigation’s focus at this point.
Cars & Fires
Let’s be clear here. Battery fires are scary but they get lots of press attention precisely because the are still relatively rare. Gasoline car fires are enormously frequent yet get almost no national news. According to the National Fire Prevention Association, in 2015, there were 174,000 gasoline fires in vehicles. 445 people were killed as a result and 1,550 injured. The economic losses associated with those fires totaled $1.2 billion. But do you see any headlines about them? No, me neither.
The battery fires get attention because they involve new technology that first responders are unfamiliar with. “We have a ways to go in educating firefighters. Especially in areas of the country that they really haven’t seen that many electric vehicles yet,” Andrew Klock of the National Fire Protection Association tells KTVU News in San Francisco.
Klock started the alternative vehicle training program for the NFPA, one of the main sources for firefighter safety training in the nation. He estimates that including his agency’s own training program, only 30% of firefighters across the U.S. have any training to handle emergencies involving alternative vehicles, which includes cars with hydrogen fuel cells as well as lithium-ion battery packs.
After the crash in California in March, Mountain View fire chief Juan Diaz wrote a 13 page report detailing the special challenges a battery fire presents to firefighters. Firefighters said they put the fire out in two minutes but soon discovered the battery fire in the electric vehicle would smolder for hours and reignite multiple times. “The battery began to overheat even though we had already cooled the battery and it continued to reignite,” said Diaz. “We don’t have the tools to deal with a battery that is completely, basically destroyed.”
The Mountain View fire department called Tesla for help. Its technicians needed to partially dismantle the battery but that did not entirely render the battery safe. “In this particular case, six days later, the temperature inside those cells increased to the point of ignition. That’s why the car reignited,” said Diaz. “You have stored energy that is frankly unstable.”
Only after the NTSB and Tesla de-energized the battery two weeks later was it finally rendered safe. A copy of his memo has been shared with every fire department in the San Francisco Bay Area. In it, Diaz warns his colleagues to be on guard if an electric car is in a garage when they respond to a house fire. “If the battery is damaged, then we’re going to have to basically monitor that vehicle for a prolonged (time) — could be days — to make sure it doesn’t reignite,” Diaz says.
The Cut Loop
Firefighters and other emergency workers are exposed to the possibility of electric shock if they cut into an electric vehicle in order to extricate the people inside. Almost every electric vehicle manufacturer provides a cut loop — a section of wiring that can be severed safely to uncouple the chassis from the electrical energy stored in the battery.
But as of now, there are no national standards for where the cut loop should be installed, so emergency workers must be familiar with multiple car models when they respond to the scene of an accident involving an electric car. In the March incident in California, the front of the Model X was obliterated, including the area where the cut loop was supposed to be.
KTVU reports that the electric vehicles manufactured by BYD in Lancaster, California, have no cut loops installed. Those vehicles use batteries with chemistries that are reportedly much safer and less flammable.
Correction: A spokesperson for BYD reached out to CleanTechnica to correct the KTVU report with the following statement:
“The report is absolutely false. All BYD buses have two emergency kill switches installed; one in the drivers dash area which when held for three seconds disconnects the batteries from the outside world and one in the rear compartment, which is the disconnect plug, isolating the batteries. In addition, BYD’s Iron Phosphate electric battery chemistry is completely fire safe, unlike other electric vehicles on the market,” said Macy Neshati, Senior Vice President of BYD Heavy Industries.
To its credit, Tesla has an extensive training program available to help emergency workers understand the unique problems associated with electric cars and has solicited input from firefighters and emergency personnel when designing its cars to make them safer in the event of a collision.
The issue is not with Tesla; it is with the enormity of getting the word out to every fire department and emergency service. It is possible that solid state batteries may one day eliminate the danger of thermal runaway. Until then, we can only hope the NTSB investigation finds better ways to deal with battery fires in a way that is safer for all concerned.