Boeing thinks it has the 787 battery problem licked.
The aircraft maker has unveiled what it calls a “comprehensive set of improvements that will add several layers of additional safety features to the lithium-ion batteries on 787 commercial jetliners are in production.” Boeing says they could be ready for initial installation within the next few weeks.
In addition, new enclosures for 787 batteries also are being built and will be installed in airplanes in the weeks ahead.
The fleet of Boeing 787 Dreamliners operating in the U.S. was grounded in January pending the outcome of an investigation of the problems with the batteries.
These improvements, the company says, will allow operators to resume commercial flights with their 787s as soon as testing is complete and the U.S. Federal Aviation Administration (FAA) and other international regulators grant their final approval.
"We are following all of the necessary protocols to get our new design fully approved and properly installed so that we can help our customers start flying as soon as possible,” said Boeing Commercial Airplanes President and CEO Ray Conner. “We're simultaneously moving out on an effort to resume deliveries but completing our certification work and getting the delivered fleet flying again is our first priority."
The improvements include enhanced production and operating processes, improved battery design features and a new battery enclosure.
Enhanced production and operating processes processes
The first layer of improvements is taking place during the manufacture of the batteries in Japan. Boeing teamed with Thales, the provider of the integrated power conversion system, and battery maker GS Yuasa to develop and institute enhanced production standards and tests to further reduce any possibility for variation in the production of the individual cells as well as the overall battery.
Four new or revised tests have been added to screen cell production, which now includes 10 distinct tests. Each cell will go through more rigorous testing in the month following its manufacture including a 14-day test during which readings of discharge rates are being taken every hour. This new procedure started in early February and the first cells through the process are already complete. There are more than a dozen production acceptance tests that must be completed for each battery.
New battery design features
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 affecting each other.
New battery enclosure
The battery case will sit in a new enclosure made of stainless steel. This enclosure will isolate the battery from the rest of the equipment in the electronic equipment bays. It also will ensure there can be no fire inside the enclosure, thus adding another layer of protection to the battery system. The enclosure features a direct vent to carry battery vapors outside the airplane.
New titanium fixtures are being installed in the electronics equipment bays to ensure the housing is properly supported.