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Boeing completes certification testing for new 787 Li-ion battery system

Boeing completed a 787 certification demonstration flight on line number 86, a Boeing-owned production airplane built for LOT Polish Airlines. This flight marked the final certification test for the new Li-ion battery system, completing the testing required by the US Federal Aviation Administration (FAA). (Earlier post.)

The flight departed from Paine Field in Everett, Wash. at 10:39 a.m. Pacific with a crew of 11 onboard, including two representatives from the FAA. The airplane flew for 1 hour and 49 minutes, landing back at Paine Field at 12:28 p.m. Pacific.

The crew reported that the certification demonstration plan was straightforward and the flight was uneventful. The purpose of the flight was to demonstrate that the new battery system performs as intended during normal and non-normal flight conditions.

Boeing will now gather and analyze the data and submit the required materials to the FAA. Boeing expects to deliver all of the materials to the FAA in the coming days.



Hope they got it right his time?


There are those among us who believe the engineers who designed the battery control and charging system for the 787, mistakenly designed the system to maintain a trickle charge at a voltage that over time caused the batteries to overcharge, albeit over a long period of time, nevertheless, they overcharged the batteries and caused thermal runaway.

Forget all you know about Lead batteries, Unlike Lead batteries, you do not trickle charge Lithium batteries. No matter what Lithium chemistry, you undercharge them, usually to about 80% and then cut off all charging until they drop down to about 20% from use. Then you repeat the charge cycle back up to about 80%. So you end up cycling the battery from 80% down to 20% and then back up to 80%.

Unlike the Lead battery which loses its power in a linear way as it discharges, the Lithium battery can maintain almost it's full discharge power from an 80 to 20 percent state of charge. Additionally, the Lead battery is kept at full charge to minimize sulfur contamination and extent its life. Lithium batteries should not be charged to 100%, ever. and they should never be discharged to a zero state of charge, ever.

It will be interesting to learn if the 787 upgrades include this approach; or, if the engineers have taken the approach to devised a fire- proof container to isolate the batteries from the airframe. In my opinion using both changes would be appropriate until the engineers learn more about building safe airborne batteries systems.

It's ironic that the reason Lithium batteries were selected in the first place was to save weight; but, now they are losing this weight advantage by build a heavy steel shelter around the Lithium batteries.


You seem to agree that the major problem may not be the batteries per se but how they were mis-treated or mis-controlled or mis-monitored etc.

On-board (specially airborne) batteries must be fully supervised at all times. Operation conditions must be correctly and continuously monitored. Overloads (i/p or o/p) must be limited to short burst. Overcharging must be avoided at the cell level.

Trying to circumvent control systems weakness with a steel enclosure may not be the best way to solve the problem.

It seems obvious that users may have to redesign and improve their control systems. Tesla may be able to help.


I would hope the engineers know the difference between lead/acid and lithium batteries, if not they have no business working on the project.

It is my belief that Yuasa does not have enough experience making large format lithium batteries, so their design and quality control is behind the industry. If that is the case, making a new battery box will not do the job.


The fix or fixes may be a lot more than a steel enclosure or box. The environment (hardware and software) must be suited/adapted to the battery technology used.

Why Boeing failed to do it right is a good question.

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