Fun fact: most gasoline car fires are started by electrical issues. Mechanical fuel pumps died out with the carburetor, just about every car made has hot wires going to the gas tank. The conflagration is completely fueled by gasoline though. Diesel is pretty hard to ignite, you can toss a burning match into a pool of diesel and the match will go out. But once ignited it’ll burn like a champ.
Both li-ion and lithium polymer batteries still have many kilograms of lithium. A lithium-ion battery pack for a single electric car contains about 8 kilograms (kg) of lithium, according to figures from US Department of Energy science and engineering research centre Argonne National Laboratory. It may be a small percentage of the total battery pack and coolant weight, but it’s still a lot of extremely explosive metal.