Thermal runaway. It may sound like the name of a long-lost 1980s Arnold Schwarzenegger action flick. Actually, it's way more dangerous than that.
Hard to stop
Thermal runaway is what happens when a lithium-ion battery can no longer control its internal temperature (ever notice how hot your phone gets when you're downloading a chunky file?) and it self-ignites. The resulting fire is (a) spectacular and (b) really hard to stop, as the battery fuels its own fire, and dousing it with water and foam doesn't really do much.
You can easily imagine the sort of fire that might be caused by the large battery of an electric car, and if your imagination doesn't quite go that far, then a quick trawl of YouTube will soon give you an idea of what happens in this situation. Suffice to say, it ain't pretty.
Envelope a flaming vehicle
Thankfully, Vanguard Fire and Rescue, based in Donabate, Co. Dublin, has a solution, and it's called the Fire Cloak. Again, that sounds like the name of an awesome action movie, but in this case, it's a heavy fabric, impregnated with fire-resistant materials and silica quartz and a silicon polymer coating, and with enough weight to simply envelop any flaming vehicle and put the flames out. It's simple physics - if you deny a fire, even a battery fire, oxygen, then it simply can't burn.
The fabric of the Fire Cloak has a melting point of more than 800 degrees Celsius, and it's flame-resistant at temperatures of up to 1,000 degrees celsius in continuous use, including temperature spikes of up to 1,600 degrees Celsius. It's also pretty easy to use - you simply unfold it and, keeping to a suitably safe distance, drag the fabric over the car or battery that is on fire. It also helps to contain some of the deeply noxious fumes that are caused by a battery fire.
Use pre-emptively
The Cloak can be used more than once, depending on the severity of the fire it's been used to douse, and it can be used pre-emptively - such as in cases where there is a suspicion that a vehicle might be about to have a thermal runaway event. Draping that vehicle in a Fire Cloak will stop a fire from developing in the first place.