GM says it’s a good idea to drain the power out of the Volt battery pack if it’s in a bad accident. That makes sense. After all, if a car is totaled one of the smart things to do is drain the gas tank. This bit of wisdom is one takeaway from an excellent article in The Economist that was written in response to some recent government tests that have caused Volt batteries to catch fire—after damaged batteries were allowed to sit for days or weeks.
Gas is dangerous because it contains so much energy—orders of magnitude more than you’d find in a battery pack. But its energy density is also why gasoline-powered cars can travel hundreds of miles on a fill-up, even though internal combustion engines are terribly inefficient, while electric vehicle owners have to fret about finding an outlet.
So, in a sense, what we really need are batteries that are more dangerous–at least in the sense that they store far more power than today’s batteries–so we can travel long distances in an electric car. That would allow us to get rid of the really dangerous part of the Volt—the gasoline tank used to fuel its range extending generator.
According to the Wall Street Journal, it wasn’t the battery cells inside the pack that caused the problem anyway.
GM engineers believe they can fix the battery and retrofit cars already on the road without an extensive redesign, people familiar with the situation said.
The company says a damaged coolant line is behind the problem.
In the crash tests, a break in the coolant line caused coolant to leak onto wiring in the battery. After time, the coolant crystallized, causing a short.
This might explain why the Nissan Leaf, which doesn’t bother with coolant, hasn’t had any trouble.