TOKYO -- GS Yuasa Corp., the supplier of lithium ion batteries used in the Boeing 787 Dreamliner as well as in electric and hybrid vehicles made by Honda Motor Co. and Mitsubishi Motors Corp., has been cleared of responsibility for the fires that have plagued batteries in the airplane.
The grounding of Boeing’s newest jet cast a shadow over electric vehicles when the plane’s smoking lithium ion batteries became the focal point of safety investigations.
But the clouds partly lifted on Monday when Japan’s Civil Aviation Bureau and the U.S. Federal Aviation Administration ended a probe, giving GS Yuasa an initial clean bill of health.
The joint investigation began Jan. 21, with both agencies combing over GS Yuasa’s factories in Japan.
Authorities wrapped up the inspection a week later, finding no manufacturing, design or quality problems that would have triggered the mysterious overheating, Japan Civil Aviation Bureau official Yasuhiro Yamada said.
Fire on the tarmac
Regulators have been looking at the batteries since problems with the power packs forced the global grounding of all 787s this month. In one incident, a GS Yuasa-made battery caught fire in a 787 sitting on the tarmac in Boston. Another glitch forced a 787 to make an emergency landing in Japan.
The lithium batteries used in the 787 are different in design from the batteries used in hybrid and electric vehicles, and are made in different factories. But the problems initially caused GS Yuasa’s stock price to tumble and spurred questions about a battery chemistry that is still relatively new in cars.
A GS Yuasa spokesman said his company plans no changes to its car battery design or production after the 787 incident.
Other probes continue
Investigators still haven’t pinpointed the root problem, Yamada said. A separate probe continues by the U.S. National Transportation Safety Board and its Japanese counterpart.
Regulators now are turning to the Japanese maker of the 787’s battery monitoring unit. Yamada declined to identify the company but said it was based in Kanagawa prefecture and is not GS Yuasa.
GS Yuasa has separate battery-making joint ventures with Honda and Mitsubishi Motors.
The Honda collaboration, called Blue Energy Co., began supplying Honda in April 2011 and now makes lithium ion batteries for the Honda Civic Hybrid, the Acura ILX Hybrid, the Honda CR-Z and the Accord Plug-in Hybrid.
The GS Yuasa-Mitsubishi joint venture, Lithium Energy Japan, has been supplying Mitsubishi with lithium ion batteries since 2009. Its batteries go into the Mitsubishi Outlander plug-in hybrid, the i electric car, known as the i-MiEV in the United States, and the Japan-market Minicab electric microvan.
Neither automaker is changing its battery procurement nor its production plans in the wake of the 787 investigation.
“It has been more than three years since MMC first started sales of EVs, and we have shipped approximately 30,000 units globally. As of now, there have been no reports of any fire or overheating damage,” a Mitsubishi spokeswoman said. “MMC has not made any changes following this issue.”