ANA B787’s Main Battery Cells Damaged by Heat, Japan Board Says

Cells of a main battery on an All Nippon Airways Co. Dreamliner that made an emergency landing were damaged by heat, Japan Transport Safety Board said, as authorities deepen investigation into the cause of fires that caused worldwide grounding of the Boeing Co. 787s.

All the eight main battery cells on the All Nippon jet that made the emergency landing on Jan. 16 sustained “thermal damage,” Safety Board chief Norihiro Goto told reporters in Tokyo today. Further investigations are needed to identify the the cause of damage, Goto said.

Damage to battery electrodes may have been caused by overheating from the thermal runaway within the cell, Goto said. Thermal runaway occurs when the heat generated within a battery builds up faster than it can dissipate.

The global Dreamliner fleet was grounded after the All Nippon B787 made the emergency landing at Japan’s Takamatsu airport because of a battery-fault warning. A week earlier there was a battery fire on a Japan Airlines Co. 787 in Boston. The U.S. safety experts determined the fire had originated in a lithium-ion battery.

Boeing may suggest a temporary fix to improve the 787’s ability to withstand overheating of its lithium-ion batteries as soon as this week, the Seattle Times reported, citing unidentified people familiar with the plan.

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