By John D. Stoll 

A123 Systems, a lithium-ion battery maker for electric cars and other business sectors, is suing Apple Inc. for what it alleges is an "aggressive campaign to poach employees."

The complaint, filed in Massachusetts earlier this week, names five employees that have either defected to Apple or appear to be in the process recruiting others to join Apple. A123 believes Apple aims to build a competing battery business, partially relying on expertise from former A123 employees to help it succeed.

Apple declined to comment on the suit. A123 officials couldn't be reached for comment.

Backed by a $250 million government grant, A123 was once a promising player in electric vehicles, but filed for bankruptcy protection in 2012 amid slower-than-expected battery advances, high costs of development and slow consumer acceptance of electric cars.

The battery maker says Apple's efforts threaten A123's own business and leave it scrambling for qualified replacements, efforts that leave the company vulnerable following its restructuring. Apple has also hired auto industry talent from Daimler AG's Mercedes-Benz unit and from Tesla Motors Inc.

The suit comes as Apple gears up to challenge Tesla, General Motors Co. and other auto makers in developing an electric vehicle. The Cupertino, Calif., company has several hundred employees working secretly on a project code-named "Titan" that included initial design work on a vehicle that resembles a minivan, The Wall Street Journal reported Friday.

A123 has operations in Germany, Michigan, Massachusetts and China and is now a subsidiary of China's Wanxiang Group.

The lawsuit was earlier reported by Reuters.

Daisuke Wakabayashi contributed to this article

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