Battery maker Ener1 Inc., which has almost 400 employees in the Indianapolis area, has fired its chief executive to improve the flagging company’s performance.

Ener1 replaced CEO Charles Gassenheimer this week with Chris Cowger, who was the New York-based company’s president, according to a public filing. Gassenheimer is also required to resign as chairman.

Ivy Tech President Thomas J. Snyder, a board member of Ener1, also was appointed to take the role of non-executive chairman of the board.

Ener1’s stock has plunged 95 percent this year and the company has been struggling to survive. In August, Ener1 said it was “determining whether the company has sufficient liquidity to fund its operations.” It’s also restating its financial results for 2010 and the first quarter of 2011, and has not filed its second-quarter report.

Cowger, a former vice president at computer processor-maker Advanced Micro Devices Inc., will “enhance the company’s ability to execute its business and financial plans in the current economic environment,” Ener1 said in the filing.

"We are fortunate to have hired Chris Cowger earlier this year," said Snyder in a prepared statement. "He's done an excellent job re-focusing Ener1 on the needs of its current and potential customers."

Ener1’s Indiana-based battery-manufacturing subsidiary EnerDel Inc. received an $118.5 million grant from the U.S. Energy Department in 2009 to help the company expand its production capacity. In January, Vice President Joe Biden visited an Ener1 factory in Indianapolis to promote companies building green vehicles.

Company shares were priced at $4.17 when Biden visited the plant on Jan. 26. The shares closed at 15 cents each Wednesday. Ener1 has a market value of $32 million, according to data compiled by Bloomberg.

Brian Sinderson, a company spokesman, declined to comment on the management changes or the company’s financial situation in an e-mailed message.