Battery maker Ener1 files for bankruptcy, tied to Think Global's bumper

Nobody was that surprised when EV maker Think Global drove off into the Chapter 11 sunset, but now it's towed an even bigger company along with it. Ener1 invested heavily in Think and also manufactured the lithium-ion batteries for its cars, but all it got in return was a lethal $69 million hole in its balance sheet. The company was de-listed from Nasdaq last month and now it's seeking bankruptcy protection to restructure $81 million in debts. If it fails to get its finances in order, organizers of the 2014 Winter Olympics may need to look for another power source.