HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
  |  REGISTER  |  LOGIN  |  HELP
News
Electronics & Test

Were the Boeing 787 Batteries Cooled Properly?

NO RATINGS
Page 1 / 2 Next >
View Comments: Newest First|Oldest First|Threaded View
<<  <  Page 5/6  >  >>
Paul Murk
User Rank
Bronze
Were the Boeing 787 Batteries Cooled Properly
Paul Murk   1/28/2013 1:25:43 PM
The litium battery must be observed in its used enviroment. We are talking low atmospheric pressure and the batteries could be outgassing causing a rupture between layers. Include with that plane vibration from jet engines could play in deterioating loose layers within the battery. The colder temperature at that altitude could have cause contractions the batteries should not have seen. As I remember the batteries should have thermal monitoring device and balance circuits to prevent heavy discharge and charge. So Rapid short within the batteries due to enviromental such as atmospheric condition not designed into the battery compartment would give a clue why the thermal sensing did not have time to respond and shut down.

You cannot analyze this by the damaged batteries alone. And new set for enviromental testing needs to be done to characterize the destruction.

RFI-EMI-GUY
User Rank
Silver
Re: Cooling System
RFI-EMI-GUY   1/28/2013 11:48:23 AM
It looks like control electronics reside inside the battery pack, so yes they would be subject to rising temperatures AND if electrolyte sprays on the control board all bets are off. This does not appear to be an intrinsically safe design.

nelso7926
User Rank
Iron
Re: Design Decisions
nelso7926   1/28/2013 10:58:32 AM
NO RATINGS
This was a massive integration effort with literally thousands of verification tests. Notwithstanding it's relative criticality, if this is the biggest issue Boeing can pat themselves on the back, but (as previously mentioned) they must move expeditiously to arrest the problem, accept full culpability, and implement a lasting fix before their market share begins to suffer. The Defense industry has thought me that these post-production woes are intrinsic in a project of this magnitude; thank God the problem was discovered without catastrophic consequences.

Nancy Golden
User Rank
Platinum
Re: Cooling System
Nancy Golden   1/28/2013 10:55:34 AM
NO RATINGS
Battar, your principle is sound but the article suggests that the cooling system may have been inadequate. Seems to me they might not have asked the question properly...and in a critical application safety margins for proper operation would be pretty important.

bdcst
User Rank
Platinum
Re: Cooling System
bdcst   1/28/2013 10:51:24 AM
NO RATINGS
Many Lithium ion batteries are not actively cooled but do manage not to burst into flames.  Most laptop batteries, camcorder batteries, etc., manage to function without active cooling.

Looking at the photos of the Boeing 787 battery pack I can only make out a single pair of high current output pins that ties the battery to the aircraft's power bus.  If so, then all charging and discharging is going through that single pair of contacts, which means the cell monitoring and charging circuitry must live inside the battery.  So, if the battery got too hot, possible runaway condition, it could have fried the controller thus disabling any chance of shut down or external alarm.

It would be foolish to not have additional wiring to enable external monitoring and control of the pack.  Virtually every Lithium ion camcorder battery communicates with its host as do many other consumer and professional battery packs.

Not having active cooling and external monitoring of system temperature for an aircraft battery system would seem foolhardy.

adip
User Rank
Iron
Re: Design Decisions
adip   1/28/2013 10:51:05 AM
NO RATINGS
There is someting fishy,for decades I have used embedded temperature sensors in all batteries, it is a part of my designed cell balancing and battery management systems, surely sudden temperature surges would be recorded -of course it will not prevent explosion due to O2 accumulation. I have seen cost saving measures causing accidents -but in aerospace!!

Nugent_56
User Rank
Gold
unproven technology..
Nugent_56   1/28/2013 10:38:30 AM
NO RATINGS
It would seem that not enough is known about the characteristics of this chemistry when used in aircraft systems where high altitudes are encountered. If a cooling system is deemed necessary, it will require redundancy for safety purposes. This of course will require futher testing and approval by the FAA for airworthyness.  Perhaps a step back to a known and proven battery technology could be used temporarily at the cost of reduced capacity, but at least it will get the aircraft flying once again until a new, improved battery design can be readied.

Toaster
User Rank
Silver
Re: Design Decisions
Toaster   1/28/2013 10:37:08 AM
I was a Boeing Engineer for a while and I worked on the 767 and 777 projects. I know something about Boeing. Yes, weight savings is very important. BUT SAFETY is the highest priority. So high, in fact that no technology is used that has not been thoroughly tested and confirmed to be safe. I really don't understand why this is happening, (and I will not guess, as I am an ME) we will find out eventually. Oh and yes, "The original Engineer isn't even in the picture" is somewhat true. Once an engineering design is completed by "The original Engineer" The design is circulated through all the engineering departments for their blessing, and modification (if any) before it is allowed to be installed in an airplane.  The design may or may not look like the original after everyone has gotten their hands on it.

 

l_jhanson
User Rank
Silver
Re: Cooling 'built in'?
l_jhanson   1/28/2013 9:52:10 AM
The division I worked for several years ago had a similar Lithium-ion battery 'thermal event' on a much smaller scale in a consumer market portable radio... We did not experience any fire, but there certainly was sufficient energy released to create a lot of smoke and reduce the radio to a bubbling mass of melted plastic. The cause seemed to be a short resulting from insulating materials being capable of sliding with vibration... The entire experience was perplexing...the experts were telling us it couldn't happen, yet it was!

ChasChas
User Rank
Platinum
Re: Design Decisions
ChasChas   1/28/2013 9:49:51 AM
Since we are all in the guessing mode, I'll guess too.

The weight savings was a big temptation so they calculated the risks and made a decision to go with this battery.

The surprise came in real life when the battery ended up working much harder than anticipated. Accessories?, add-ons?, custom build? (Sales says yes, yes, yes, and the original engineer isn't even in the picture.)

<<  <  Page 5/6  >  >>
Partner Zone
Latest Analysis
Factory floor engineers may soon be able to operate machinery and monitor equipment status simply by tapping their eyeglasses.
GE Aviation not only plans to use 3D printing to mass-produce metal parts for its LEAP jet engine, but it's also developing a separate technology for 3D-printing metal parts used in its other engines.
In this TED presentation, Wayne Cotter, a computer engineer turned standup comic, explains why engineers are natural comedians.
IBM's new SyNAPSE chip makes it possible for computers to both memorize and compute simultaneously.
The “Space Kid,” 11, will be one of the first civilians to have his design manufactured in space by NASA, thanks to the City X Project, which inspires kids to think about new 3D-printed inventions that could be useful for humans living in space.
More:Blogs|News
Design News Webinar Series
9/10/2014 11:00 a.m. California / 2:00 p.m. New York
7/23/2014 11:00 a.m. California / 2:00 p.m. New York
7/17/2014 11:00 a.m. California / 2:00 p.m. New York
6/25/2014 11:00 a.m. California / 2:00 p.m. New York
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Sep 22 - 26, MCU Software Development – A Step-by-Step Guide (Using a Real Eval Board)
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  6


Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.
Next Class: September 30 - October 2
Sponsored by Altera
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Copyright © 2014 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service