The battery is not to blame for ongoing problems with Boeing's 787 Dreamliner, US and Japanese officials said Monday.
The investigation now shifts from battery-maker GS Yuaka to the manufacturer of a monitoring system, The Associated Press reported.
More from GlobalPost: Dreamliner grounded by FAA over safety concerns
All 50 of Boeing's 787 Dreamliners are grounded worldwide following numerous incidents involving the aircraft earlier this month.
Battery fires, a cracked windshield, fuel leaks and computer problems were reported.
GS Yuasa stock jumped on the news it is no longer being investigated, gaining nearly 5 percent in Tokyo trading, CBS News reported.
More from GlobalPost: Inquiry expands into Boeing Dreamliner batteries
The focus has now shifted to the electrical system that monitors battery voltage, charging and temperature.
"We are looking into affiliated parts makers," Japan transport ministry official Shigeru Takano told BBC News. "We are looking into possibilities."
While the ongoing investigation may prolong the Dreamliner's grounding, the shift away from a faulty battery raises the prospects of Boeing not having to do a major redesign, Keith Hayward, head of research at the Royal Aeronautical Society, told BBC News.
According to Agence France-Presse, US regulators have said they will not allow the 787 to fly again until they are sure its problems have been fully resolved.