Temperature during Lithium thermal runaway

[Dorfie]

I was wondering at what temperature the lithium batteries self destruct during thermal runaway. I was wondering if an aluminum case will contain the battery meltdown without melting itself. It will be vented.
Thanks.
Johan

[DennisRhodes]

Just watched a NOVA special on renewable and energy storage research. A lot of good tech info on Lithium and lithium ion batteries as well as several battery types I have never heard of. The program was very good and had some footage of Li battery destruction from various methods ie puncture, overcharge and runaway recharge. You don't want to be anywhere around when that happens. I believe I heard somewhere around 1800 Deg F on Li ion battery fault. They had some impressive footage. Might look for a replay of that Nova.

[mbauer]

Used to use Li-poly batteries for RC stuff. Used a thing called a battery bunker to store/charge them in. Could handle the 1100 deg fire. Quick search shows the same temp for Li-ion.

Most aluminum melts at around 800.

They also make a ceramic fabric pouch for the same purpose. Check at local hobby stores to find them.

Mike

[Ironflight]

Every time a person asks a question about "Lithium battery", I cringe a little, because I know the next post will be about fires, explosions, and all manner of dangerous things. But there are many different types of Lithium batteries, and they all have different characteristics. Misinformation - especially on the internet - abounds, mostly because, yes, there have been fires associated with many (but not all) Lithium battery types.

If the OP is talking about Lithium polymer batteries, like you find in RC models, then yes - there have been lots of fires. If he's talking about liFePo (Lithium Iron Phosphate) batteries - that's "iron", not "ion" - as are becoming popular in lightweight starter batteries, it's a different story. People carelessly use all these terms interchangeably, thinking it's all the same stuff, just spoken with different accents. But they are different. There are a couple of popular stories floating around about in-air fires in experimental using "Lithium" batteries, but no one has been able to find out exactly which batteries these were, as the people reporting on them are always talking second or third hand.

So be precise in your questions, or the answers you get back will just confuse the issue even more.

So to the OP - which batteries are you talking about?

[Alan Carroll]

As it happens someone has done a study of this recently. You have to pay if you want the full article but I was able to access it via my university library.

The authors found that thermal runaway occurred when the LiFePO4 battery surface was heated to a temperature of about 126 ?C (=259 ?F). I would venture that your aircraft battery is unlikely to ever see that temperature absent a fuel- or oil-fed fire (in which case you may have bigger problems to worry about).

The measured combustion temperatures were highly variable. Th lowest they reported was 650 ?C, and the highest was 986 ?C (1807 ?F). I think the latter is well above the melting point of any aluminum alloy.

[bret]

I have read all the arguments about these batteries for a couple of years now and I have changed my thinking about what to hope for if my Earth X battery self ignites, a lot of folks say steel enclosure for the battery but mine is in this custom homemade aluminum one. So now if this battery self ignites, and burns through the box, I hope I can identify this fire and hope it WILL melt through and then I can pull a momentary 6G pull up to drop the battery out the bottom and switch over to my internal 20 AH backup battery.............wishful thinking but its a thought......any thoughts on this madness.......?

[Alan Carroll]

Originally Posted by bret

I have read all the arguments about these batteries for a couple of years now and I have changed my thinking about what to hope for if my Earth X battery self ignites, a lot of folks say steel enclosure for the battery but mine is in this custom homemade aluminum one. So now if this battery self ignites, and burns through the box, I hope I can identify this fire and hope it WILL melt through and then I can pull a momentary 6G pull up to drop the battery out the bottom and switch over to my internal 20 AH backup battery.............wishful thinking but its a thought......any thoughts on this madness.......?

It dawned on me as well that a battery box that melts might be a good thing if it allows the burning mess to simply depart the airplane. Hopefully it doesn't fall on someone (FAR 91.15 comes to mind). I'm not sure though if the cables might tend to hold it in place?

[JohnInReno]

Originally Posted by Alan Carroll

...
The authors found that thermal runaway occurred when the LiFePO4 battery surface was heated to a temperature of about 126 ?C (=259 ?F). I would venture that your aircraft battery is unlikely to ever see that temperature absent a fuel- or oil-fed fire (in which case you may have bigger problems to worry about).
...

I have temperature strips directly on the EarthX900 on the firewall. It has not seen 130F since installed Feb 2016 even in an AZ summer.

https://www.mcmaster.com/#temperature-strips/=166ych3

[rv6ejguy]

A sealed SS box with overboard venting is the best bet. If you've seen the smoke produced by one of these batteries when it's compromised, you'll know you probably won't survive if that gets into the cockpit.

[BillL]

Originally Posted by Dorfie

I was wondering at what temperature the lithium batteries self destruct during thermal runaway. I was wondering if an aluminum case will contain the battery meltdown without melting itself. It will be vented.
Thanks.
Johan

If you are talking about something like EarthX LiFePO, then it probably will.

Here is a plot of some batteries forced into thermal runaway and the temperatures. The non Fe batteries (typically) have higher energy per mass and that results in higher temps during runaway. Also, the electrolytes can self ignite on discharge of these higher energy batteries causing fires. Note the excursion line for #1. It appears it began its thermal event around 100C.
Let me know if you want the full report. Lithium Cobalt had peaks around 850-900C - not counting fires. To be sure, Ross has it right: sealed, stainless, vented overboard. Earth X offers aluminum.