Lithium Ion Battery
At the risk of not playing into the media hype that HEBs / EVs are more dangerous than ICEs due to the batteries (we heard the same like of crap when HEVs came out), from the second paragraph of the article:
[R]egulators believe the batteries are safe and do not pose a greater fire risk than gasoline-powered engines, a National Highway Traffic Safety Administration official told The Associated Press.
I'be been a volunteer firefighter and EMT for over 15 years, and seen more than my fair share of motor vehicle accidents involving HEVs, and am yet to see any added fire risk or danger from the battery pack. The reality is there is an incentive for many corporations to paint the EV technology in a poor light. It is up to us as early adopters, evangelists or enthusiasts of EVs to ensure the reality isn't distorted by the hype (and I know hype, I'm the head of Marketing Technology at a large ad agency).
To me this is like the line of crap that is still out there that due to the battery production process the carbon footprint of a HEV / EV is greater than an ICE. Every reasonable assessment of this has shown it to be utterly false. Even Top Gear, no fan of Tesla, debunked that myth.
So, before we all start upping our life insurance policies, remember that an EV has far fewer flammable things stored in large quantity. Fire (or, more accurately, combustion) needs three elements to occur; fuel, oxygen and ignition. There is a reason gas is often called "fuel"... and also a reason the thing you start the car with is called an ignition.
@Mike_ModelS_P457 Good answer, you cover everything I also want to say.