Green Auto News: Mr. Green Car: Are electric cars safe?
By Allen Penticoff
The National Highway Traffic Safety Administration (NHSTA) just issued a statement that their recent investigation into battery fires in Chevy Volts finds that there is no fire risk problem with the Volt or any other electric car that is any more significant than a conventionally-fueled vehicle.
I have been giving Mr. Green Car talks lately about the state of green transportation. As the subject of electric vehicles is a major portion of these talks, the subject of the Chevy Volt battery fires always comes up — or I just dive in and explain it before the question is asked.
Before NHSTA released their report, I had already known the fires were crash test related and not on-the-road accidents. I’ve told folks that while lithium-ion batteries do have the potential to catch fire, that these high-tech cars have very effective liquid cooling systems for their battery packs — this includes hybrids like the Prius. Right now, you have a regular car driving around with a tank full of very flammable liquid — gasoline — and they do catch fire at times, crash or no crash, and that has not deterred anyone from buying one since the Pinto.
The Chevy Volt is a plug-in hybrid car that has just been put in the hands of the public in 2011. While undergoing crash testing with the Insurance Institute for Highway Safety, they did some severe side impacts. Apparently, it was the equivalent of smashing into a pole right in the middle of the side of the car. This deformed chassis structure distorted the tunnel that protects/houses the lithium-ion batteries and damaged the battery cooling system, causing a leak that led to overheating. The cars did not even catch fire right away, but sometime much later.
Chevrolet investigated and decided to do a voluntary recall of some of the early production Volts to reinforce the area in question, add a battery coolant level sensor and a tamper-resistant bracket to the coolant reservoir to prevent overfilling. They also created procedures to discharge the batteries completely in the event of an accident.
NHSTA’s press release states their investigation “concluded that no discernable defect trend exists and that the vehicle modifications recently developed by General Motors reduce the potential for battery intrusion resulting from side impacts.”
The fire incidents did wake some engineers up, though — they realized the need to spell out how to depower these high-voltage battery systems in the event of an accident. This knowledge needs to be in the hands of first responders and towing companies. It is not a job for amateurs, and is probably best not done at all if one does not know the proper procedure because these battery systems have enough voltage to kill if mishandled.
I consulted with my friend, who is trained to work on Volts, and he recommends that first responders be instructed/trained to assume the whole car is “hot” — that is voltage leaking to the body. They will need to test for this condition and wear appropriate protective gear. He says the power can be disconnected, but there is no ready way to drain the batteries quickly. I’d suggest that if there is a bad accident involving a Volt or other electric vehicle and you are a first responder, you find a factory-trained technician pronto. To mess with the power cables and do something wrong — which is highly likely — may destroy the vehicle or cause injury. Post-accident response training is something the auto industry will need to address as a whole.
So many new cars are coming out as hybrids, plug-in hybrids and pure electric cars that it is quite difficult to keep up with them all. And this is just the beginning of the trend. Perhaps it is best that these few incidents came to light. It prompted the government safety engineers to evaluate the data on electric vehicles and determine their risks. They’ve done that now and come to the conclusion we’re good to go full steam ahead on electrifying our transportation.
From the Jan. 25-31, 2012, issue