A recent article in MIT Technology Review (probably paywalled) is about dealing with electric vehicle battery fires.
It's based on the research by an EV battery pack designer who is also a volunteer firefighter, and who now consults with fire departments on this issue. His conclusion: let them burn, while trying to isolate them from surrounding vehicles and structures. Isolating can mean anything from covering them with a fire blanket, to (as one case study illustrated) moving the EV to a vacant lot with a forklift while it is burning. Wow.Fires need three things to continue to burn: fuel, oxygen, and heat. Typical firefighting techniques involve interrupting one or more of these constituents. But lithium battery packs provide all three all by themselves, as part of a "thermal runaway" chemical reaction.
Traditional vehicle fires are typically centered around the easily accessible engine compartment, and can usually be put out in minutes with hundreds of gallons of water. EV fires are centered around the huge battery pack often underneath the vehicle, and - if they can be put out at all - may take hours and thousands of gallons of water, and may later spontaneously reignite.
The article has many worrisome case studies, including one where an EV owner accidentally drove his car off a pier in Florida. When the battery pack became saturated with electrically conductive salt water, it shorted and ignited... and continued to burn under thirty feet of water. Wow again. EV batteries igniting when saturated with salt water from flooding in coastal areas due to hurricanes is apparently a growing phenomena.
As a typical homeowner with lots of lithium battery packs - some quite large, for power tools - I've gotten concerned enough about this that I don't leave the packs on chargers when no one is at home (not even phones, laptops, or tablets). And I have a small chest of drawers inside the house just inside the door from the garage in which I store my expensive charged lithium battery packs (which don't like the cold either, but that's more of a longevity issue). I do keep rechargeable gear in both automobiles and on both motorcycles (jumper battery packs, tire inflators), and I worry about that.
Mrs. Overclock recently bought some small fire blankets, one of which is now out in the garage next to the wall mounted fire extinguisher.
Update: another recent article on the same topic from the same source, the gist being preventing EV battery fires is a lot more practical than extinguishing them.
