Aircraft lithium battery fires

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Let'sgoflying!

Touchdown! Greaser!
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Dave Taylor
copied with permission:
We have a Cozy MKIV in the shop that I am working on the wiring. The builder installed a Lithium Iron battery. Yesterday, I heard a soft poof and then a hiss coming from the battery, and within ten seconds the battery was spewing a huge smoke plume and was melting the battery's case. We scrambled to get the hanger door open and the plane pushed outside. While the smoke
decreased after about 3 minutes the heat continued. I decided I could get in the back of the plane and cut the battery cables with a good set of cable cutters. So, I held my breath and climbed in and as quickly as I could I cut the cables and tossed the battery out on the ground. It was then I was able to get a video of the battery as it continued to self destruct. The battery burned for at least ten minutes before it quit spewing smoke, sparks and its internal parts.
We have just finished installing a pair of these batteries in a Long-EZ and within a few days of installation one began showing signs of not holding a charge and I noticed it was getting warm to the touch. I removed it and Aircraft Spruce promptly warranted the battery and sent us a new one. The one that burned yesterday was showing similar signs of not holding a charge and about an hour before it burned I noticed it was warm to the touch. I had no idea at the time of the first battery failure how close it was to the catastrophic results that we saw yesterday.
It is absolutely horrifying to think of that happening while airborne. As fast as it escalated it would have filled the cockpit with that terrible smoke and fumes in just a couple seconds. By the time I took the video linked below the smoke had tapered off considerably. In my opinion no one in the aircraft would have survived had this happened while in the air. No one should even consider having these batteries in the aircraft with them.
One of the scariest things I have seen. Might as well have a wing come off, the outcome is the same. I have added a link below to the video I took. Have a look at the video, you'll be shocked.
”
Follow-up: “I have had a conversation with (the battery manufacturer). He seems cordial, honest and sincere. He had been briefed on my recent experience with his batteries and was aware of my opinion. Frankly, he said nothing to change my mind. He says the most likely cause of the fire is overcharging of the battery. I accept that. But, he says it could also be caused by completely discharging the battery and then trying to charge it. Says if you completely discharge it such as leaving the master on even once, the battery is ruined and you might as well throw it away. He told me he was aware of two fires occurring while in flight. Both he says were caused by the on board charging systems. Both fires were in Kitfox aircraft with Rotax engines and charging systems. Both times the pilot was able to make an emergency off field landing and no one got hurt. Both batteries were mounted on the engine side of the firewall. He told me that he designed a system for maintaining the batteries installed by a prominent kit manufacturer. He says that they mounted them in the engine compartment and installed a fireproof case around the battery that would vent the smoke overboard in the event of a runaway. He told me he knew that the batteries were a "smoke bomb" when they burned. He says he makes a special charger for the batteries but, he also says it is not required.
 
Wow.
I have read similar stories elsewhere; enough to keep me away from them.
 
I don't claim to be an expert on LI batteries but they appear to be easily susceptible to thermal runaway. From reports I've seen, it appears to be more of a problem at altitude than at sea level. Hopefully, they can find a cure for that. Latest technologies always seem to come with glitches.
 
Oops!

That's the brand and type of battery I installed in my Sky Arrow several years ago. It sits in front of where my feet are, in the nose of the plane (no engine there, it's a pusher).

12663501433_bbe45d32d1_z.jpg


Someone on the RV site strongly recommended it be encased in a vented battery box. Maybe a modification to make on my next annual?
 
I'd not want one. ... the technology just isn't ready for aviation IMHO.
 
Batteries are chemical storage devices. Chemical reactions have thermal implications, amplified by the desire to increase the energy density of our battery packs.
As we try to stuff more energy in less (charge) time into them the thermal issues become the limiting factor. Tesla has had a few of their $100k Model S sedans melted down due to battery pack fires, Sony had some similar laptop battery pack fires, Samsung had to withdraw a smartphone model from the market, and everyone here I am sure will recall Boeing had issues with the lithium-ion batteries in the 787 early on.

Battery technology is advancing incrementaly, not in giant leaps. And this is the reason, despite the hype, I think electric car range improvements are going to be slow in coming.
 
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FastEddieB said:
Oops!

That's the brand and type of battery I installed in my Sky Arrow several years ago. It sits in front of where my feet are, in the nose of the plane (no engine there, it's a pusher).

12663501433_bbe45d32d1_z.jpg


Someone on the RV site strongly recommended it be encased in a vented battery box. Maybe a modification to make on my next annual?
Click to expand...

I would not wait...
 
There was the Boeing 787 lithium battery.

Here's a photo of the one that caught on fire in a JAL airliner in Boston. A short circuit (in cell 6 in the photo) started the whole problem, which then led to thermal runaway and more short circuits in the other cells. The spread of the problem from one cell to another was made worse by a lack of spacing between cells, a lack of cooling, and a lack of vents.

It didn't take much to go from bad to worse, with lithium.

inside-787-battery.jpg
 
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The RV industry is having the same thing happening, the owners are replacing their lead acid batteries with these and not changing the inverter chargers to charge these correctly.
My new Inverter has the setting for these, But I still run 4,, 6 volt deep cycle batteries.
These worry me.
 
I'm using an EarthX in my Cub. I know lots of guys who have them and not a single problem. I don't know anyone with an Aerovoltz, FWIW. Charging the EarthX on the ground requires a special charger. No big deal. In flight I have a panel mounted status light to warn of battery problems. Most LI battery problems are operator induced. Guys think these new batteries are charged like old lead acid batteries using "smart" chargers. Too smart to read the instructions.... That's where the problems start. Click on "Why you need a lithium battery charger". Learn about them and you won't fear them.

http://tecmate.com/products/optimate-lithium-4s-9-5a-5s-7-5a/
 
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I watched a 182 burn down many years ago due to a NiCad. I think the lithium batteries are worse yet. Watching what a small lithium can do to an RC airplane I can't imagine one popping in my cessna. For the minor weight savings I think I'll stick with the tried and true lead acid. Maybe not the most efficient but its the least dangerous. With a composite plane I can't see any reason to put a lithium in it. It only takes once and if you're in the air you get no second chance.
My own opinion of course.
Frank
 
Every EX Cub owner I know uses EarthX, and I know a bunch of those guys. The only problem stories I ever hear about LI batteries is from guys who've never used one.

For guys who like emergency battery jumpers? The EarthX Jump Pack is nothing short of amazing. Tiny, powerful, and under a hundred bucks. Try one. You'll be a LI battery fan as a result.
 
this whole thingy has remembering the phrase....."light your hair on fire" :lol:
 
Li-Ion batteries require very well controlled charging and discharging. Typically in any expensive gear that's controlled by a dedicated microprocessor that measures the current going in and out, the battery or individual cell voltage(s), and temperature of the pack. With that kind of setup they can be as safe as a lead acid battery but if you just stuff a Li-Ion battery in something that's set up for a much more forgiving lead acid battery (i.e. one with simple constant voltage charging and no undervoltage disconnect mechanism) it's a ticking time bomb.

I'm surprised that there isn't a good Li-Ion battery controller available for the experimental world, might be an opportunity for me to design one?
 
gismo said:
I'm surprised that there isn't a good Li-Ion battery controller available for the experimental world, might be an opportunity for me to design one?
Click to expand...
As I mentioned above, EarthX batteries have exactly that kind of controller built in, unlike the AeroVoltz batteries. So the opportunity is narrowed somewhat by ready-built solutions existing already. Naturally, EarthX batteries are more expensive.
 
Too late. At least for the good ones. EarthX batteries have a battery management system built in.
 
Stewartb said:
Too late. At least for the good ones. EarthX batteries have a battery management system built in.
Click to expand...
all LiOn batteries have circuitry.....they have to due to the volatile nature of the Lithium chemistry. And the charging systems need to be tailored to the battery chemistry also. Charge state, discharge load and charge load are all critical in maintaining happy cells. Get one of those wrong and the cells will overheat and begin thermal runaway. ....yup....over discharge and it will go into thermal runaway.....over discharge beyond 30%....and pooof. :eek:

It ain't your father's lead acid .....lots of smart folks learned that the hard way, even after being schooled by folks who know.
 
Product data for other brands of LI batteries do not support your "all" statement. Which LI batteries are you using?
 
Stewartb said:
Product data for other brands of LI batteries do not support your "all" statement. Which LI batteries are you using?
Click to expand...
I've worked for companies who use raw cells...been there done the hazard analysis for aircraft and consumer products....the consumer purchases a package of cells that have safety circuitry. By nature of the chemistry it has to be controlled or there will be a fire.

btw....two of my last three employers had LiOn battery fires in their labs....even after safety training.

here's something to ponder.
 
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btw....Textron/AAI and Stanley, Black and Decker (DeWalt Power tools) are the two companies I referred to above with my LiOn battery experiences.
 
IMG_0298.JPG My EarthX in a customized box in my airplane. The EarthX box is top loading. Mine is adapted to front loading since a tube blocks it from above. I did add the larger EarthX panel mounted LED battery status light in plain view above my switch and breaker sub panel on the instrument panel. The battery also has an on-board status light (seen in the pic).
 
Checkout_my_Six said:
here's something to ponder.
Click to expand...

I would put this up there with Ghost Hunters and "You won't believe..." stories.

The story may have some factual information. But with the title of the story being "The Deadly Cargo Inside MH370: Exploding Batteries Explain the Mystery" prevents me from reading the story since if the author is willing to start with that, my guess is the whole story is made up.

Or did they find MH370 and were able to analyze the wreckage and determine that it was brought down by an "exploding battery"?

Didn't think so.
 
Checkout_my_Six said:
all LiOn batteries have circuitry.....they have to due to the volatile nature of the Lithium chemistry. And the charging systems need to be tailored to the battery chemistry also. Charge state, discharge load and charge load are all critical in maintaining happy cells. Get one of those wrong and the cells will overheat and begin thermal runaway. ....yup....over discharge and it will go into thermal runaway.....over discharge beyond 30%....and pooof. :eek:

It ain't your father's lead acid .....lots of smart folks learned that the hard way, even after being schooled by folks who know.
Click to expand...

As said above, a controller is required AT ALL TIMES. Li-ion batteries are exceptionally sensitive to charge and discharge cycles as well as total charge. The power density and discharge rate of a Li-ion is substantially better than Lead Acid, but they are really very unstable. The energy density in one large enough to turn over your engine is not something to be trifled with. If you've never had a piece of electronics blue screen on you or had to restart you smart phone, go ahead and put a Li-ion in you aircraft. Please label it as such so I can make sure my loved ones to not fly in said plane.

Note that the Tesla has a lead acid battery to ensure the Li-ion controller always has power as well as to power the Li-ion disconnect in case of an accident. The modern Li-ion battery is truly a technological wonder, but it simply is NOT ready for prime time in aviation. If Boeing can't get it right, what do you think the chances are that the small guys can.
 
There is a logical fallacy called "hasty generalization". One hears an anecdote or two and jumps to a conclusion, which may or may not be warranted.

I'd kind of like to know the data on lithium iron battery fires. How many are out there? What percentage of those have had fires?

And how does this compare to lead acid batteries?

Because the reasoning is flawed does not mean the conclusion is wrong. I'd just like to see more data and fewer anecdotes.
 
1st of all the Li-Ion batteries Boeing uses and we get in EartX are two totally different animals. I'm not an expert but do your research and you will find the LI-iron types to be much safer than the Li-Ion although a bit less efficient i.e. heavier. Boeing was going for the absolute lightest battery with the most power available at the time, EarthX is not that, and quite a bit cheaper then what the very efficient Li-Ions would be in the size we are talking about. Bought a battery for your phone or computer lately, wonder why its so expensive, they are not Li-iron? As an aside I built my electrical system for my bipe just as all this was playing out. One thing that will kill a Li-Ion is over charge. Anything over 14V on a 12V battery puts you in the dangerous zone so I searched until I found a variable voltage regulator and had it set to 13.7V max output from my alternator just to protect my plane and my butt! Glad I have it so now even if the internal circuitry failed on my EarthX I am covered with a little redundancy.
 
The drama queens apparently don't read tech data. The EarthX aircraft batteries have built-in "controllers". You can post the info but you can't make guys read it!
 
Stewartb said:
The drama queens apparently don't read tech data. The EarthX aircraft batteries have built-in "controllers". You can post the info but you can't make guys read it!
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yes, they "all" have controllers.....or circuitry for safety purposes.
 
Stewartb said:
My EarthX in a customized box in my airplane. The EarthX box is top loading. Mine is adapted to front loading since a tube blocks it from above. I did add the larger EarthX panel mounted LED battery status light in plain view above my switch and breaker sub panel on the instrument panel. The battery also has an on-board status light (seen in the pic).
Click to expand...

It looks like this is installed on the inside of the firewall? EarthX batteries have failed and belched lots of acrid smoke, too. What would your plan be should that happen with your installation?
 
Early batteries, maybe, and very few of those. I've done my due dilligence and decided to move forward with it. Lots of friends have them and not a single issue. Several local dealers selling them to airplane guys and the only failure stories are unsubstantiated internet stories. Not concerned. Besides, I have a fire extinguisher and big swing-up windows on both sides, but those have nothing to do with my battery choice.
 
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Stewartb said:
Early batteries, maybe, and very few of those. I've done my due dilligence and decided to move forward with it. Lots of friends have them and not a single issue. Several local dealers selling them to airplane guys and the only failure stories are unsubstantiated internet stories. Not concerned. Besides, I have a fire extinguisher and big swing-up windows on both sides, but those have nothing to do with my battery choice.
Click to expand...

Fair enough.

I have had a Shorai LiFEPo4 battery installed for the last three years / 600+ hours. It lacks a BMS, but the FMEA done before the installation shows that it would not help with any failure modes *for my aircraft*, as the other systems onboard (crowbar overvoltage, EMS alarms, etc) prevent overvoltage situations from happening in the first place. I did put the battery on the firewall as mitigation of battery outgassing as identified by the FMEA.

The point is to understand the risks and have a mitigation plan you are comfortable with.
 
FYI, read about EarthX batteries on their website. They differentiate between aviation and their other batteries by adding redundant safety controls. I don't know if the panel status light output is unique to their airplane batteries but I like it. New technology usually has a learning phase. These batteries are performing well from all I've talked to.
 
Stewartb said:
Early batteries, maybe, and very few of those. I've done my due dilligence and decided to move forward with it. Lots of friends have them and not a single issue. Several local dealers selling them to airplane guys and the only failure stories are unsubstantiated internet stories. Not concerned. Besides, I have a fire extinguisher and big swing-up windows on both sides, but those have nothing to do with my battery choice.
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Fire extinguisher won't do a damn thing for thermal runaway with a battery.

Doing a project in my Heat transfer class now about how to design insulation such that one cell can thermally runaway and not affect the others. It's pretty scary hard-to-control stuff. Treating it lightly and saying "my friends don't have problems" isn't really a good excuse or a good way to tell safety.
 
I "think" remembering a NiCad runaway that melted right through a LearJet and dropped to the ground.
 
Yes, you guys have all the (internet) answers. Carry on. I have an airplane to finish.
 
Stewartb said:
Yes, you guys have all the (internet) answers. Carry on. I have an airplane to finish.
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I mean... these things aren't really (internet) opinions... its physics. Pretty hard to argue with laws of physics.
 
Or statistics. Like I said, I did my due diligence. You guys should do yours when you build your own airplanes, too. My plane, my choice, my reasons. I'm sorry I took the time to share them.
 
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