After a crash tested Chevy Volt burned in a National Highway Traffic Safety Administration storage facility three weeks following the crash test, that agency is now working with automakers to possibly come up with rules to protect people that handle electric vehicles after a wreck.
The Detroit Free Press has reported that NHTSA is looking into issuing new safety rules for handling EVs with lithium-ion batteries after collisions. The electrolyte used in today’s Li-Ion batteries are is flammable. During the test, crashing the Volt sideways into a telephone pole at 20 mph, a piece of metal perforated the battery pack possibly causing a leak of those flammable materials. Then the car sat on the storage lot for three weeks without the battery being discharged and it’s possible that a spark ignited the electrolyte. Internally, GM protocols call for discharging the battery in the event of a serious collision. Every Volt has GM’s On-Star service and in the event of a collision serious enough to activate the airbags, Chevy is notified and dispatches a team to investigate the wrecked Volt and discharge the battery.
The Volt response team is one reason why information about discharging was not shared with NHTSA. GM’s procedures were in place for real world cars, not cars at testing facilities. Apparently, nobody at GM thought to tell NHTSA and nobody at NHTSA thought to ask GM about special procedures for their extended range EV.
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When he’s not busy doing custom machine embroidery at Autothreads Ronnie Schreiber edits Cars In Depth and contributes to The Truth About Cars and Left Lane News
Lithium Ion batteries have lately been used quite extensively in model airplanes. One thing required for safety is that they be recharged in an explosion proof container. You want to drive around sitting on a potential bomb? Oh wait, gasoline is known to explode too, just watch all the movies that show cars going boom. But NBC had to put model rocket engines on the sides of the GM trucks they were doing their expose on a couple of decades ago when they couldn’t get them to explode by running into them with another car. Gasoline just floods out and evaporates after a time. Yes sparks can ignite the fumes but how often does that happen? In real life, not much. The problem with Li-Po batteries is, you can’t tell if it’s going to go or not. There’s not necessarily a tell tale leak or other symptoms. It just happens. So you’re toodling down the road and your is in need of recharging and you stop to get a quick charge and boom.
Several years ago I had occassion to work with Lithium for a submerged vehicle application. We found that, in some cases, it was a bit hygroscopic and tended to flash if it got wet, and it didn’t take much moisture to occur. Properly contained it was safe, but in the cited case, where something possibly penetrated the battery case, and based on the very limited information, it could be that after sitting several weeks in ‘dead storage’ (unclear if it was inside or in the weather), it sucked in enough moisture to cook off.