Johnson Controls has filed an appeal in the bankruptcy court of the 11 December, 2012 sale order approving Wanxiang's purchase of A123 Systems.

As part of the sale order, the court ordered the escrow of the break-up fee and expense reimbursement that Johnson says is due to the company under its stalking horse agreement with A123.

"We appreciated the opportunity to serve as stalking horse, which resulted in significant value to the estate, creditors and employees," said Johnson Controls Power Solutions president, Alex Molinaroli.

Johnson Controls added A123 was directed to place the breakup fee and expense reimbursement in escrow after A123's creditors' committee suggested to the court that Johnson Controls was lobbying against the sale of A123 to Wanxiang.

"As a market leader and major employer with significant operations in the US, we have expertise and insights regarding the industries we serve, which are important resources for leaders and decision makers," said Molinaroli.

"Our representatives regularly provide educational material and expert opinions on many topics including advanced batteries, lithium-ion technology and the various applications they serve."

The company added the "significant issue" of US regulatory approval required for any sale of A123 to Wanxiang has been a constant challenge dating back to Wanxiang's original failed attempt to acquire A123 earlier in 2012 prior to bankruptcy.

"Johnson Controls has consistently maintained national security questions tied to the core technology used in all of A123's businesses represent a risk to the sale which cannot be dismissed until resolved by the government review process," said a Johnson Controls statement.

"Should the sale of A123 Systems to Wanxiang not be completed for any reason, Johnson Controls remains open to considering future opportunities to acquire relevant portions of A123's assets, keeping this critically important technology in the US, preserving jobs and furthering the purpose of the American Reinvestment and Recovery Act," said Molinaroli.

The component supplier declined to match a higher bid for A123 put forward by Wanxiang.

A123 selected Wanxiang's bid of US$257m against a set of competing complementary bids by Johnson Controls for the automotive and government assets and NEC for the grid and commercial assets.

Wanxiang was not immediately available for comment.