Boeing Contains Battery Failures on Dreamliners
On January 7 and 16, 2013, two lithium-ion battery fires occurred on parked Boeing 787 Dreamliners at Boston's Logan Airport and Takamatsu Airport in Japan. The incidents led to a global fleet grounding of the US-registered aircraft by the FAA.
The National Transportation Safety Board (NTSB) was unable to conclusively identify the root cause of either failure, despite months of investigation. Boeing engineers took a pragmatic approach, assuming another battery failure could occur and designing a containment system that would prevent a single faulty cell from threatening the plane.
This 'defense in depth' strategy set aside the question of what triggered the original failures and focused on managing the consequences of a repeat event. Rather than redesigning the aircraft's electrical architecture or changing the battery chemistry, Boeing implemented changes to the 787's battery system, including added insulation between cells, hardened charging electronics, and a stainless-steel containment box.
The containment system was designed to prevent heat from one failing cell spreading easily to its neighbors. The battery's lithium-cobalt-oxide chemistry remained unchanged, despite pressure to switch to a less energy-dense but more thermally stable chemistry.