Re: 700 bars ! Yikes !
In a car Li battery fire, chances are that the circuit is interrupted and there is no longer high voltage present. All cars have a way of splitting the traction battery pack to make it safe. Firefighters will have to spend more time learning where they are located rather than sitting around watching football when they are on shift.
With liquid petroleum fuel, you don't have a 50l fuel air bomb. You have a tank that is primarily fuel with very little Oxygen in relation. A nearly empty tank being the most dangerous, but no where near that 50L. Only 18%ish of air is Oxygen and fuel vapors will be dominant in the tank. Certainly you can get a boom, but not to the extent you are implying. This is why we can drive around with a can full of highly flammable fuel on board. It's not flammable until there is Oxygen present.
Batteries, OTOH, don't need an outside oxidizer. They can burn under water. The hotter you get them, the more likely the next cell is to burst into flames, so cooling the pack down is important to limit the chances of self re-ignition from damaged cells slowly going critical. It might take a new way of handling wrecks to safe the batteries rather than just dumping them in an impound yard and walking away.
I remember a night on the beach where we got a chuck of old VW engine case ignited in the fire pit. The fire brigade had no idea what it was. Bright AF and we knew better than to look at it. The fireman didn't. I don't assume much knowledge about fire/chemical reactions on their part since.
Biting the hand that feeds IT
