Spotlight on Technology: How Safe are Lithium-ion Battery Packs?
If you're concerned that the lithium-ion battery packs in your hybrid car could be as dangerous as the batteries in the recently grounded Boeing 787 Dreamliner aircraft, remain calm. John Voelcker of Green Car Reports explains that while the battery types may be similar, their chemistries are actually quite different.
In his article at Green Car Reports, Voelcker offers a scientific explanation describing the differences between chemistries of the lithium-ion batteries:
"The cells in the 787, from Japanese company GS Yuasa, use a cobalt oxide (CoO2) chemistry, just as mobile-phone and laptop batteries do. That chemistry has the highest energy content, but it is also the most susceptible to overheating that can produce "thermal events" (which is to say, fires).
Only one electric car has been built in volume using CoO2 cells, and that's the Tesla Roadster. Only 2,500 of those cars will ever exist.
The Chevrolet Volt range-extended electric car, on the other hand, uses LG Chem prismatic cells with manganese spinel (LiMn2O4) cathodes.
While chemistries based on manganese, nickel, and other metals carry less energy per volume, they are widely viewed as less susceptible to overheating and fires."
Here's a little more information related to the safety of lithium-ion battery packs powering the Teslas and Chevy Volts:
In a dozen Google searches using various combinations of the words "NHTSA, Tesla, battery, fire, lithium-ion," we were unable to find any news related to battery fires in Tesla cars related to thermal events. Keep in mind, most of these cars have been on the road since 2008, so there have been plenty of opportunities for such an instance to occur. They seem pretty safe. Tesla DID have a recall of 439 vehicles related to a low-voltage auxiliary cable which could chafe against the edge of a carbon fiber panel in the vehicle and possibly causing a short, smoke and a possible fire behind the right front headlamp of the vehicle. This is not the same kind of problem.
In research related to the Chevy Volt battery fire risk, we learned that in targeted National Highway Traffic Safety Administration testing intended to duplicate a situation in which a Volt caught fire while parked at a NHTSA testing center in Wisconsin three weeks after a side-impact crash test May 12, one car had no problems, one battery fire started after seven days, one battery had sparks and smoke after it was turned over, but no instances of an actual fire. The problem in the Volt case seems NOT to be the chemistry or the format of the batteries themselves, but the possibility that leaking coolant could cause a short, possibly leading to a fire. Outside of their own testing, NHTSA noted that there are no known "real-world" instances of battery problems causing fires to erupt after a driver crashes a Volt, and added that "Volt owners who have not been in a serious crash do not have reason for concern."
