China's biggest auto parts maker beat out rivals with a $257 million (1.6 billion yuan) bid for the bankrupt battery supplier but while the takeover has received court approval, it still must be cleared by the U.S. Committee on Foreign Investment.

"We have been creating and saving jobs in our investments in the U.S., and I am proud of that," Pin Ni, head of Wanxiang's U.S. operations and son-in-law of the group's founder, told Reuters. He said A123 would not be folded into the Chinese group's lithium ion battery unit.

U.S. politicians have objected to A123's taxpayer-financed lithium ion technology ending up in the hands of an economic rival and pressure has mounted on Treasury Secretary Timothy Geithner, the head of the foreign investment panel, to block the deal. Those politicians include lawmakers in Michigan, where A123 has several facilities.

Ni declined to comment on concerns about U.S. national security, saying it was a U.S. government matter. "There is a process in place to deal with such concerns, and I am all for it," he said.

"A123 is an American company and will be an American company," Ni said in comments seeking to allay concerns about potential job losses.

As Chinese companies invest more overseas, U.S. suspicions about their intentions have often erupted. The United States has rejected a bid to build wind farms by Ralls Corp., owned by two executives of China's Sany Group, and multiple deals by Huawei Technologies Co., a Chinese telecommunications equipment maker.

A123's technology is used in U.S. power grid systems and military hardware, and Wanxiang's bid excludes A123's defense contracts. But a group of former military leaders and industrial consultants said in a statement last month that A123's commercial and defense businesses were too similar to allow the sale to a Chinese company.

But people close to Wanxiang's deal believe concerns over the loss of A123's know-how to China are overblown because some of the technology is already available in China through A123's previous business dealings.

David Vieau, chief executive of A123, said the Waltham, Mass., company has 1,000 workers in China that produce batteries. The deal with Wanxiang was carefully crafted and doesn't involve A123's business with the U.S. government and its military forces, he told Reuters.

"I don't personally see any national security considerations associated with making batteries in China," Vieau said. "We have been doing that for the last six years. I am not sure how that can be perceived as a threat, but that is not for me to decide."

For two years, A123 has been working closely in technology development with SAIC Motor Corp., a state-owned automaker in Shanghai that has joint ventures with General Motors and Volkswagen AG.

A123 also has a factory near Shanghai where it assembles lithium ion batteries made of battery cells that it also produces there. "A123 has lots of engineers in China already," one of the individuals close to the deal said.

But some experts and industry insiders, while declining to be identified because of business interests in China, say there is still much for the United States to lose because A123 has not really made the most important part of its technology available to the Chinese.

That know-how involves technology that helps shrink lithium particles to nano dimensions, helping boost a battery cell's energy density, and putting more power into a smaller box.

Vieau said A123 was not sharing that nano technology nor the cell-making technology but was providing those cells as "black-box" technology to SAIC.

A123 filed for bankruptcy in October as demand for electric vehicles did not live up to expectations and it was forced to recall defective car batteries. Its customers include Fisker Automotive, General Motors and BMW.

Johnson Controls, which narrowly lost the auction with a $251 million bid made with NEC, has said it remains interested in A123 if Wanxiang fails to get approval from the U.S. government.