WILMINGTON, Del. - The Official Committee of Unsecured Creditors in the Chapter 11 bankruptcy of B456 Systems Inc., the renamed version of alternative energy company A123 Systems, on April 29 filed a brief objecting to a more than $27.91 million claim asserted by General Motors LLC that alleges breach of contract (In Re: B456 Systems Inc., No. 12-12859, Chapter 11, D. Del. Bkcy.).