Mitsubishi Motors reported two separate incidents with Li-ion battery packs: one, a fire in a i-MiEV battery pack at the Mizushima battery pack assembly plant; the other, heating and melting in a pack installed in an Outlander plug-in hybrid electric vehicle.
In the Mizushima event, the pack was connected to charge-discharge test equipment. There was no injury to personnel, or damage to the main plant building and equipment.
Mitsubishi noted that the supplier, GS Yuasa, had made a change in its manufacturing process, and that since there is a possibility of failures that may occur in this context, it is investigating in collaboration with GS Yuasa. Mitsubishi has shipped 45 units (for specified corporations) and 68 units of that type of pack for the domestic market as spare parts.
The incident with the Outlander PHEV occurred after the vehicle had been fully charged and stood for one day. Upon trying to move the vehicle, the driver detected an odor, which was traced to melting of part of the battery pack.
The melting was traced to the overheating of some of the battery cells—also supplied by GS Yuasa.
GS Yuasa is also the supplier of the Li-ion battery pack for the Boeing 787; that pack is different from the Mitsubishi packs in manufacturing process, design and chemistry, Boeing said.
In 2007, Mitsubishi Corporation (MC), Mitsubishi Motors Corporation (MMC) and GS Yuasa Corporation established the joint venture Lithium Energy Japan to manufacture large-capacity and high-performance lithium-ion batteries. (Earlier post.)