Print 12 comment(s) - last by drycrust3.. on Feb 6 at 10:28 PM

Charred 787 battery  (Source:
The FAA is reviewing the request






Source: The Seattle Times

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Ditch the packs
By Samus on 2/5/2013 11:58:39 AM , Rating: 2
I don't get why they aren't just ditching the Li-Ion idea like many experts have suggested (specifically, Elon Musk) and go to Li-Po or LiFe? The energy density is still there to make a suitable pack sized to fit the battery compartment (which apparently can't be redesigned to size a larger pack at this stage in the aircraft's development, a huge oversight on Boeings' part.

Boeing just isn't what it used to be...the reliable workhorse F150 of the skies.

RE: Ditch the packs
By geddarkstorm on 2/5/2013 12:11:35 PM , Rating: 2
That's the most logical thing to do, to you and I, but Boeing has probably put in and already paid for a massive order of these batteries, to cover their needs for the future. That's a lot of investment to ditch, not to mention all the re-validation a new battery tech would require before the planes could fly again.

Either way, not happy days at Boeing lately.

RE: Ditch the packs
By othercents on 2/5/2013 12:44:37 PM , Rating: 3
First Elon Musk didn't suggest moving away from Li-ion. He suggested redesigning the storage system, so instead of 8 batteries in one firesafe compartment, that they put each battery into separate firesafe compartments. He also recommended redesigning the battery to be smaller, so you use more smaller batteries instead of 8 large ones. This all would allow a level of safety if one failed.

There are other requirements for using different battery technologies you also have to contend with the FAA not allowing those untested battery technologies on the airplanes. The quickest way to get the airplanes back into the air is to revert back to the proven technology that airlines use today. However it seams like a short sightedness of Boeing that they didn't design both battery technologies for the 787 just in case there was an issue. I guess this goes back to the engineers say why design for a possibility of failure if you design it never to fail.


RE: Ditch the packs
By Amiga500 on 2/5/2013 1:11:12 PM , Rating: 2

Stall the ball!! He definitely did not say that.

Her said they (Boeing) designed it to never fail... then assumed it did and built a protection mechanism... then assumed that failed and built a further protection mechanism.

Same as Airbus, same as Bombardier, same as Embraer. Its standard procedure - your fault trees must have probabilities of failure of under 10e-9 (catastrophic failure) or 10e-7 (hazardous failure).

RE: Ditch the packs
By drycrust3 on 2/5/2013 1:57:35 PM , Rating: 2

I think the issue is bigger than that, by limiting themselves to exactly that battery manufacturer producing exactly that battery-cell size containing exactly that technology they have limited the plane to only the function of just carrying passengers flying under today's airline rules.
If you look at the really successful planes, e.g. 747, DC3, etc, they are able to be easily converted to different roles.
By limiting the battery sizes to "exactly that size" you create problems when someone wants to do anything else besides carrying passengers or wants to add some new technology, especially a new technology which you can't just boot up as the passengers are boarding the plane.
For example, in the foreseeable future airlines will want to add smartphone and tablet capability to their planes, which (besides needing a change to airline flight rules) may well require a bigger Ampere-hour battery. "Sorry, can't do it."
In addition, there is a type of Moore's law, where the amount of electronics added to anything, doubles every so many years, so one would expect the amount of new electronic capability airlines will want to add to this plane could easily have doubled in 10 years. "We want to install a new high resolution 3D RADAR with 'fighter pilot helmets' for the pilot and co-pilot, that lets the plane take off and land in a smog bound airport" ... "Sorry, can't do it".
Another example is military services in various countries may be interested in the plane, but they may well want a cell that has more Ampere-hours and is more rugged than the one currently used.

RE: Ditch the packs
By Jeffk464 on 2/6/2013 9:35:29 PM , Rating: 2
You know once the plane fires up an engine plenty of juice should be supplied by the generator. At that point the battery pack just acts as kind of a buffer, right?

RE: Ditch the packs
By drycrust3 on 2/6/2013 10:28:02 PM , Rating: 2
The reason you have a battery is because you need electricity when there are no engines running. Having looked at the Yuasa brochure for this battery, it is confusing as to what the battery is capable of, except that each cell is rated at 65 Ampere-hours.
There are computer systems around which people don't want to turn off, and so, for those types of equipment, a battery is essential. As I said, as time goes by people will want to add electronic equipment to the plane, and some of that equipment will fall into the "please don't turn off unless you really really do have to" category, which will then place a demand on the battery at times when there are no engines running.
This will mean that in, say, 10 years time you will either have less "no engine" time than you do today, or you will have to install a battery with a bigger capacity (e.g. 100 Ampere hours) to get the same amount of "no engine" time as you do today; both of these scenarios are ones that airlines may not want.
By Boeing limiting themselves to such a rigidly small space for the battery, they are creating a set of problems they could easily have avoided.

RE: Ditch the packs
By zephyrprime on 2/5/2013 12:49:41 PM , Rating: 2
The battery would be twice as big if it were lipo or life. I dunno if they have the space for it or not.

RE: Ditch the packs
By mrwassman on 2/5/2013 1:59:10 PM , Rating: 1
Lithium Polymer batteries are way more hazardous and less reliable than Lithium Ions. I experiment with these batteries fairly often and the Li-Po is voted most likely to blow up. I don't understand how boeing can fuck up on testing of a battery of all things.

RE: Ditch the packs
By Jeffk464 on 2/6/2013 9:37:25 PM , Rating: 2
Hope not, I charge my lipo's under the hood of my Tacoma.

RE: Ditch the packs
By Jeffk464 on 2/6/2013 9:32:03 PM , Rating: 2
Seams like you could "flight test" the packs on the ground.

