Troubled electric-car battery maker A123 Systems, which used a $249 million grant from the US government to build a Michigan factory, is getting rescued by China's largest auto parts maker in a proposed deal that would give Wanxiang Group an 80% stake. It's only the latest in a series of distressed US cleantech companies snapped up by Chinese investors, and it's unlikely to be the last. Chinese battery makers' technology has lagged behind competitors in Japan and South Korea such as Sanyo and Samsung, says Kevin See, a senior analyst who tracks the electric vehicle industry at Lux Research. Picking up technology from struggling companies in the US can help Chinese companies compete.