Must be the Nickel-Iron Battery they are using. It has some interesting characteristics...
http://en.wikipedia.org/wiki/Nickel-iron_battery
I did a paper last semester on battery technologies, and discovered that the aluminum-air batteries
Aluminium battery - Wikipedia, the free encyclopedia have by far the best energy output per size or weight, but are only "mechanically rechargeable." Someone really needs to be working on a rechargeable version of these. EVs would become so much more viable almost overnight!!!
EDIT: It looks as if they may be using the LiFePo (one of the lithium batteries), and calling it Fe...