In the news lately is the use by Boeing of lithium ion batteries in the design of their new 787 Dreamliner and some fires/failures. Here is an article that sums things up and has a picture of a burned out lithium battery pack from the plane:
Mayday for Dreamliner: The Airplane?s Woes Explained - The Daily Beast
The folks here know a lot about batteries. Lithiums save weight with their high energy density. The Dreamliner is all about being light for fuel economy. But lithiums may also be riskier than some other battery types.
So the poll is... lithum-ion batteries in a plane that makes trans-ocean flights: smart move to save weight, or too risky?
Disclaimer: I have no involvement with either the aircraft industry or the battery industry. Just curious given the news item.
Also if anyone here has some knowledge of plane electronics, given the increased use of electronics in planes now, I'm wondering if they include a halon (or other) fire suppression system in these electronics bays in the planes? Similar to what is used in computer data centers:
https://www.youtube.com/watch?v=2fyGGqgVzCY
Mayday for Dreamliner: The Airplane?s Woes Explained - The Daily Beast
The folks here know a lot about batteries. Lithiums save weight with their high energy density. The Dreamliner is all about being light for fuel economy. But lithiums may also be riskier than some other battery types.
So the poll is... lithum-ion batteries in a plane that makes trans-ocean flights: smart move to save weight, or too risky?
Disclaimer: I have no involvement with either the aircraft industry or the battery industry. Just curious given the news item.
Also if anyone here has some knowledge of plane electronics, given the increased use of electronics in planes now, I'm wondering if they include a halon (or other) fire suppression system in these electronics bays in the planes? Similar to what is used in computer data centers:
https://www.youtube.com/watch?v=2fyGGqgVzCY
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Lithium is a very light battery technology but it does have its share of problems, and a tendency to 'thermal dissasembly' is probably formost amongst them.
That said, with good quality cells this only happens if the pack is abused (Thermal problems, over charge or discharge), but you would want to do a lot of qualification work on any pack you were proposing to fly, including such things as exploring as many of the interesting bits of the vibration/temperature/pressue/load/state of charge state space as possible.
Given this pack is allegedly basically an APU starter battery I would also be looking long and hard at fuel savings over aircraft life Vs cost to do that qualification work, it is not immediately clear that the lithium pack (Plus its rather critical protection systems) is a sufficiently big saving to justify the costs.
Lithium has a nasty trick in which it gets hot and burns hours AFTER it was abused (Seen that happen), something like a charge regulator fault or possibly even starting the APU with a flat battery (Lithium is funny that way) would do it.
I would personally not be reading too much into these stories about a very new aircraft with a LOT of new technology, the A380 (In many way a less cutting edge beast) had a raft of issues that eventually got sorted (As did the Rolls Royce engines a few years back), this will get investigated and changed so as to make it work.
Regards, Dan.
That said, with good quality cells this only happens if the pack is abused (Thermal problems, over charge or discharge), but you would want to do a lot of qualification work on any pack you were proposing to fly, including such things as exploring as many of the interesting bits of the vibration/temperature/pressue/load/state of charge state space as possible.
Given this pack is allegedly basically an APU starter battery I would also be looking long and hard at fuel savings over aircraft life Vs cost to do that qualification work, it is not immediately clear that the lithium pack (Plus its rather critical protection systems) is a sufficiently big saving to justify the costs.
Lithium has a nasty trick in which it gets hot and burns hours AFTER it was abused (Seen that happen), something like a charge regulator fault or possibly even starting the APU with a flat battery (Lithium is funny that way) would do it.
I would personally not be reading too much into these stories about a very new aircraft with a LOT of new technology, the A380 (In many way a less cutting edge beast) had a raft of issues that eventually got sorted (As did the Rolls Royce engines a few years back), this will get investigated and changed so as to make it work.
Regards, Dan.
Hey, after this thread TSA may ban all cellphones and other electronic devices on planes because they contain Li-ion batteries. They already ban liquids because they may be combustive!
http://www.youtube.com/watch?v=bZ8IsMRFM5o
http://www.youtube.com/watch?v=pizFsY0yjss
http://www.youtube.com/watch?v=bZ8IsMRFM5o
http://www.youtube.com/watch?v=pizFsY0yjss
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I ran across a NY Times article with some more technnical details:
https://www.nytimes.com/2013/01/17/...f-us-operated-boeing-787s.html?pagewanted=all
Sounds like they really went to Herculean efforts to mitigate the risk! Boeing really wanted that battery. Venting any smoke to the outside and trying to encase it so it could burn and not affect the plane. Plus some sort of auto-disconnect system. Will be interesting to see if it all winds up being enough. From the article:
Mr. Sinnett [Edit, Boeing Chief Engineer] said that if the lithium-ion batteries started a fire, it would be nearly impossible to put out because the batteries produce oxygen when burning. Mr. Sinnett said that the plane was designed to survive such an event in flight, when the cabin’s air-pressure system protects passengers and allows the plane to vent the smoke outside. The plane is also designed, he said, to contain a fire to a small area.
“Fire suppressants just won’t work on a situation like that,” he said in the conference call. “So something like that is very difficult to put out.”
Heat from the fire on the plane parked in Boston last week was so extreme that it melted the bolts holding the battery to the equipment rack. Firefighters had to use a hydraulic tool to cut it loose.
https://www.nytimes.com/2013/01/17/...f-us-operated-boeing-787s.html?pagewanted=all
Sounds like they really went to Herculean efforts to mitigate the risk! Boeing really wanted that battery. Venting any smoke to the outside and trying to encase it so it could burn and not affect the plane. Plus some sort of auto-disconnect system. Will be interesting to see if it all winds up being enough. From the article:
Mr. Sinnett [Edit, Boeing Chief Engineer] said that if the lithium-ion batteries started a fire, it would be nearly impossible to put out because the batteries produce oxygen when burning. Mr. Sinnett said that the plane was designed to survive such an event in flight, when the cabin’s air-pressure system protects passengers and allows the plane to vent the smoke outside. The plane is also designed, he said, to contain a fire to a small area.
“Fire suppressants just won’t work on a situation like that,” he said in the conference call. “So something like that is very difficult to put out.”
Heat from the fire on the plane parked in Boston last week was so extreme that it melted the bolts holding the battery to the equipment rack. Firefighters had to use a hydraulic tool to cut it loose.
That's funny. People from USSR by descend would LOL.
I always thought that only one nation can create the problem and only then put a heroic effort to mitigate it. Seems like globalisation to me.
They probably saved few pounds by not using proven MeH batteries.
All that needed by now is pressure capable vessel with pressure relief valve made of quater inch stainless steel. Question remains where to get the power when the battery dies: from the next same one installed for redundancy 😉
EDIT: Is it due to the plane not being civil derivative of the real one or it's just a new generation of engineers/managers who forgot the lessons learned hard way by older peers?
I always thought that only one nation can create the problem and only then put a heroic effort to mitigate it. Seems like globalisation to me.
They probably saved few pounds by not using proven MeH batteries.
All that needed by now is pressure capable vessel with pressure relief valve made of quater inch stainless steel. Question remains where to get the power when the battery dies: from the next same one installed for redundancy 😉
EDIT: Is it due to the plane not being civil derivative of the real one or it's just a new generation of engineers/managers who forgot the lessons learned hard way by older peers?
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Yeah, I agree, just from the news accounts it seems like the NiMeH would have been a good chioice. The weight of that explosion-proof box probably cancels out whatever weight savings they had from Li-Ion. I was reading today that one or more of the hybrid car manufacturers have gone to the safer but less energy-dense LiMN chemistry.
One thing is likely - if they have to change battery chemistry it won't fit back into the same hole in the electronics bay.
One thing is likely - if they have to change battery chemistry it won't fit back into the same hole in the electronics bay.
I find it funny people get all worked up about batteries when they are sitting in a thin walled aluminum can at 500mph loaded with tons of highly combustible explosive hydrocarbon fuel!
Stainless steel envelope
WAS A JOKE like ZEPPELIN made of lead
even with one it is really hard to contain - auto guys tried it in an early days of LiIon - it inflates like like latex air balloon...
In regard to flying on/inside a fuel tank - you won't put a ignition device into that can, would you?
Most vehicles have emergency fuel dump system - rarely used in the air - usually pane flies in circles till all fuel is consumed - again due to the fire hazard
WAS A JOKE like ZEPPELIN made of lead
even with one it is really hard to contain - auto guys tried it in an early days of LiIon - it inflates like like latex air balloon...
In regard to flying on/inside a fuel tank - you won't put a ignition device into that can, would you?
Most vehicles have emergency fuel dump system - rarely used in the air - usually pane flies in circles till all fuel is consumed - again due to the fire hazard
That venting to the outside doesn't seem to be working as planned since one of the 787s did an emergency landing after the pilot smelled smoke in the cockpit.
This seems to be about a particular chemistry (cobalt-based cathode, liquid electrolyte) being used and the fast charging scheme employed rather than Li-Ion in general - see here : Boeing's Dreamliner batteries inherently unsafe and yours may be too | Ars Technica
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Wow - that is great article! Well this part of the article is amazing:
The batteries selected for the Dreamliner "were very large scale—65 amp-hour batteries which is very, very large," said Allen. "They are very high power batteries, and they charge them to 90 percent (of capacity) in about 70 minutes. That's a very fast charge for any lithium battery of this size. And that's a problem when there isn't a cooling system incorporated."
0.9C in about one hour, with possibly no external cooling and a 65Ahr capacity! That is around the charging rate an aggressive balance charger for 18650s cells would run at, but those are typically in open air when charging. Some of those plugs with small wires in the photos running to the two circuit boards must be balance charger connections between the cells.
Well one simple thing that would help is drop the charge rate to 0.5C and take two hours instead of one. Should drop the cell temp down. Maybe they figure that plane won't be in the air that long between hops sometimes. Or liquid cool it! Run some chilled inert liquid through the thing to keep it from going into thermal runaway. 🙂
Anyone interested in the back story of these battery problems might be interested in this article - What Went Wrong At Boeing? - Forbes
Its clear from this that there's a much deeper problem at Boeing of which battery fires are only one symptom. We do indeed live in interesting times.
Also this article hints that there's not going to be a quick fix - http://www.guardian.co.uk/business/2013/jan/21/boeing-7870-dreamliner-fire-split-regulators
Its clear from this that there's a much deeper problem at Boeing of which battery fires are only one symptom. We do indeed live in interesting times.
Also this article hints that there's not going to be a quick fix - http://www.guardian.co.uk/business/2013/jan/21/boeing-7870-dreamliner-fire-split-regulators
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I'm not sure I'm OK with cutting-edge technology everywhere in an airplane. There is something to be said for proven technology, especially when safety is a concern.
Batteries are dangerous, period. The one in your car can blow up in your face, and that's one of the chemistries that are considered safe batteries.
I realize that saving (let's assume) 100 lbs on a beast like a passenger jet means who-knows-how-many fewer litres of fuel burned over it's lifetime. A lot, I'm sure.
I understand the reasons for trying to lightweight systems everywhere on the plane. I am even OK with the design team charged to find a lighter battery system; I just am not sure you should actually use the lighter battery given that they do burn at extreme temperatures and create their own oxygen environment to maintain combustion. I don't think that is a good reason to use them on an airplane.
Hey, the WWII Germans used rocket fuel based on peroxide (oxygen-bearing liquid fuel) and it worked. Their jet aircraft also used the same fuel. It was also highly corrosive and dangerous to handle. Nobody after the war continued to use that fuel (much; there are places where real rocket fuel is hard to come by; guess what they do next? They read 50-year old textbooks).
Do the research, but put the X for xperimental in there.
Let's face it ... aircraft are environmental nightmares. I understand fuel saving initiatives but in the end it's a drop into a very large bucket. The hundred or three pounds can be saved somewhere else. Safely.
Nobody ... and I mean nobody ... can argue these batteries are not a fire hazard. The company that developed the electronics for this system had a factory burn to the ground when testing. There are dead FedEx pilots whose plane burned to the ground because of LiONs in the cargo hold. Someone said something about banning laptops and cellphones ... well, for a while they were effectively banned because LiONs were banned on aircraft not so long ago. Then they relented, allowing smaller batteries onboard in checked and carryon luggage. But, yes, it was at one time not legal to carry a laptop with a LiON battery onboard an airplane.
I know what the Boeing guys are saying, and I understand what they mean. It is possible to make these batteries safely, if you dot all the i's and cross all the t's. It's been done in the consumer space, as long as you don't buy eBay replacement batteries for your laptop it's probably OK. But "probably OK" still means a fire or three every million or maybe it's 50 million batteries, or something to that effect.
So how many fires in, say, 100 or even 1 billion flights is "acceptable"? I say none, and "just one" is not acceptable to me. These aircraft have had probably a few thousand flights, and there are already multiple battery issues. Not good enough for me.
Pilots I know say that one event is manageable under almost any flight condition. So, maybe a fire, venting outside, blah blah blah is actually a manageable in-flight event at 40,000 feet over the Atlantic. But doesn't the airplane NEED electricity to work?
Those same pilots also say that if two events happen, you're in trouble, and if three events happen in succession, you are probably living your last moments on Earth.
What happens after the fire? Does everything else work perfectly?
Batteries are dangerous, period. The one in your car can blow up in your face, and that's one of the chemistries that are considered safe batteries.
I realize that saving (let's assume) 100 lbs on a beast like a passenger jet means who-knows-how-many fewer litres of fuel burned over it's lifetime. A lot, I'm sure.
I understand the reasons for trying to lightweight systems everywhere on the plane. I am even OK with the design team charged to find a lighter battery system; I just am not sure you should actually use the lighter battery given that they do burn at extreme temperatures and create their own oxygen environment to maintain combustion. I don't think that is a good reason to use them on an airplane.
Hey, the WWII Germans used rocket fuel based on peroxide (oxygen-bearing liquid fuel) and it worked. Their jet aircraft also used the same fuel. It was also highly corrosive and dangerous to handle. Nobody after the war continued to use that fuel (much; there are places where real rocket fuel is hard to come by; guess what they do next? They read 50-year old textbooks).
Do the research, but put the X for xperimental in there.
Let's face it ... aircraft are environmental nightmares. I understand fuel saving initiatives but in the end it's a drop into a very large bucket. The hundred or three pounds can be saved somewhere else. Safely.
Nobody ... and I mean nobody ... can argue these batteries are not a fire hazard. The company that developed the electronics for this system had a factory burn to the ground when testing. There are dead FedEx pilots whose plane burned to the ground because of LiONs in the cargo hold. Someone said something about banning laptops and cellphones ... well, for a while they were effectively banned because LiONs were banned on aircraft not so long ago. Then they relented, allowing smaller batteries onboard in checked and carryon luggage. But, yes, it was at one time not legal to carry a laptop with a LiON battery onboard an airplane.
I know what the Boeing guys are saying, and I understand what they mean. It is possible to make these batteries safely, if you dot all the i's and cross all the t's. It's been done in the consumer space, as long as you don't buy eBay replacement batteries for your laptop it's probably OK. But "probably OK" still means a fire or three every million or maybe it's 50 million batteries, or something to that effect.
So how many fires in, say, 100 or even 1 billion flights is "acceptable"? I say none, and "just one" is not acceptable to me. These aircraft have had probably a few thousand flights, and there are already multiple battery issues. Not good enough for me.
Pilots I know say that one event is manageable under almost any flight condition. So, maybe a fire, venting outside, blah blah blah is actually a manageable in-flight event at 40,000 feet over the Atlantic. But doesn't the airplane NEED electricity to work?
Those same pilots also say that if two events happen, you're in trouble, and if three events happen in succession, you are probably living your last moments on Earth.
What happens after the fire? Does everything else work perfectly?
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Problem solved
Living in NY, I noticed in the paper that the batteries were also used to de-ice the wings.
Just put the batteries in the wings.....
In 3 weeks, I'll be on one of those planes.
Living in NY, I noticed in the paper that the batteries were also used to de-ice the wings.
Just put the batteries in the wings.....
In 3 weeks, I'll be on one of those planes.
Interesting stuff out in the news this evening. Boeing talked about 4 redundant lithium ion battery safety systems in the 787 design. Sounds like the NTSB has decided they all failed:
NTSB says safety systems on Boeing's 787 failed; probe ongoing - latimes.com
"...the National Transportation Safety Board said backup protections in the aircraft’s lithium ion batteries and electronics systems have failed."
"These events should not happen," Hersman said. "As far as design of the aircraft, there are multiple systems to protect against a battery event like this. Those systems did not work as intended."
Sounds more and more like the situation is going to wind up as a redesign effort to some extent. But the Boeing engineers may go on strike in less than a week:
Boeing engineers union leaders to vote on strike authorization | Reuters
* grabs popcorn* 🙂 Will be interesting to see how the whole thing plays out!
NTSB says safety systems on Boeing's 787 failed; probe ongoing - latimes.com
"...the National Transportation Safety Board said backup protections in the aircraft’s lithium ion batteries and electronics systems have failed."
"These events should not happen," Hersman said. "As far as design of the aircraft, there are multiple systems to protect against a battery event like this. Those systems did not work as intended."
Sounds more and more like the situation is going to wind up as a redesign effort to some extent. But the Boeing engineers may go on strike in less than a week:
Boeing engineers union leaders to vote on strike authorization | Reuters
* grabs popcorn* 🙂 Will be interesting to see how the whole thing plays out!
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Quote
Of course, Boeing might be better off choosing a safer, but less powerful NiMH battery. Sadoway reckons that this battery would have to be 50% heavier — perhaps 37 more pounds — representing 0.01% of the 787′s 502,500 pound weight in order to deliver sufficient current to the 787.
End Quote
MIT Professor: Battery Fix Could Ground 787 Until 2014 - Forbes
Of course, Boeing might be better off choosing a safer, but less powerful NiMH battery. Sadoway reckons that this battery would have to be 50% heavier — perhaps 37 more pounds — representing 0.01% of the 787′s 502,500 pound weight in order to deliver sufficient current to the 787.
End Quote
MIT Professor: Battery Fix Could Ground 787 Until 2014 - Forbes
Sounds like Airbus is considering throwing in the towel on their lithium-ion batteries now:
Airbus May Switch A350 Battery to Avoid 787 Lithium Woes - Bloomberg
Airbus May Switch A350 Battery to Avoid 787 Lithium Woes - Bloomberg
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