Today Boeing announced today that it has commenced production on what it calls comprehensive improvements to the safety features of the Dreamliner's lithium ion batteries and said that it could be ready to proceed witih initial installation within the next few weeks. It is also building new enclosures for 787 batteries that could be be installed in airplanes in the weeks ahead.
This photo from March 2012 shows a Japan Airlines 787 taxiing towards the runway at Paine Field in Everett, Wash.
The APU battery contains eight lithium-ion cells. The NTSB's examination of the battery's external casing showed that the right side of the case had the most extensive damage. Most of the cells were found to be electrically short-circuited.
Boeing today described its "comprehensive set of improvements" to the lithium ion batteries this way, in part:
"Changes inside the battery will help to reduce the chances of a battery fault developing and help to further isolate any fault that does occur so that it won't cause issues with other parts of the battery.
"To better insulate each of the cells in the battery from one another and from the battery box, two kinds of insulation will be added. An electrical insulator is being wrapped around each battery cell to electrically isolate cells from each other and from the battery case, even in the event of a failure. Electrical and thermal insulation installed above, below and between the cells will help keep the heat of the cells from impacting each other."
"Wire sleeving and the wiring inside the battery will be upgraded to be more resistant to heat and chafing and new fasteners will attach the metallic bars that connect the eight cells of the battery. These fasteners include a locking mechanism.
"Finally, a set of changes is being made to the battery case that contains the battery cells and the battery management unit. Small holes at the bottom will allow moisture to drain away from the battery and larger holes on the sides will allow a failed battery to vent with less impact to other parts of the battery."