Google "sony laptop fire"...
This a safety issue with lithium batteries (no matter who's car their in).
Lithium batteries have been around for 60+ years and until recently were used only for cold climate applications by the military / goverment as they were deemed unsafe for consumer use. The lithium batties you see in use today have internal short-circuit protection but your cell phone's battery getting crushed could still catch fire. I've got a popular electronics article from 30+ yrs ago that explains the history of lithium batteries and (at that time) why they were not used. Improper charging can cause explosion / fire like just about every other rechargable battery (alkaline batteries can be recharged, but very carefully!!).
I don't consider the danger here any higher than say, 20 gallons of gasoline???
Ever seen a lead-acid battery in a fire? (they go boom too)
If Tesla's were more common, they'd be wearing this crown of thorns. But GM stuck their neck out... (First out, First sued)