After bankruptcy, a buyout by a Chinese firm, and more than a hundred million dollars in taxpayer money, the lithium-ion battery maker A123 Systems, Inc., is getting a new name: B456 Systems, Inc. A123, which produces batteries used in electric cars, has changed its name to B456, the company announced Thursday in a regulatory filing. The company filed for bankruptcy in October of last year and was later purchased by Chinese firm Wanxiang. The Department of Energy awarded A123 a $249 million grant in 2009, of which the battery maker had received $133 million when it filed for bankruptcy.