Can LiFePO4 Batteries Combust in Thermal Runaway Event?

[Will Prowse]

I would like to challenge anyone reading this to find a photo or video of a LiFePO4 creating internal combustion from thermal runaway event.

I keep seeing people comment that LiFePO4 can combust, but UL listed companies and battery studies are telling me otherwise. Where are people coming up with this idea? LiFePO4 raw cells are being constructed in packs without individual cell fusing, and no one is blinking an eye.

But there are articles from reputable people (Jack Rickards videos as well) stating that they can combust.

So if someone can PLEASE email me evidence of LiFePO4 combusting from thermal runaway, I would love to see it (my email is willprowseiv@gmail.com)

Here is some of my proof that LiFePO4 is NOT combustible:
https://www.osti.gov/servlets/purl/1395736
https://relionbattery.com/uploads/images/misc/Relion_SafetyLithiumBattery.pdf
https://www.mdpi.com/1996-1073/11/9/2191/pdf

So the cobalt based ones have oxygen loosely attached, and when hot, can cause combustion. This makes it more hot, and thermal runaway goes nuts! And LiFePO4 does not have this problem, no cobalt. Am I missing something?

And this is what combustion is: high-temperature exothermic redox chemical reaction between a fuel and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combustion in a fire produces a flame, and the heat produced can make combustion self-sustaining. LiFePO4 heat generation, is not self-sustaining, and does not create enough heat to combust cells next to it.

It will create heat, but not much. There is no "cascade" effect, from what I can tell. It is not considered a oxide based lithium ion chemistry. And I remember when learning about rocket fuels (scott manley's youtube channel!), that pressure and temperature have a huge part to play in this reaction.

But what I find interesting is the thermal runaway properties of LiFePO4 at various temperatures... it does not increase.

And simpli-phi, which creates high quality, UL listed battery packs, states this as well:


Technically, any battery can pose a fire threat because it can cause a conductor in a system to heat up (if OCPD not present), and set something else on fire. But the internal chemistry of a lifepo4, as I can tell and what safety studies have shown, is that it cannot. If you disagree with this, please let me know below.

 

[svetz]

That's quite the challenge Will!

I think you're right for a normal healthy LiFePO4 cell in say a power-wall application.

Like all lithium chemistries the underlying discharge reaction is exothermic (i.e., generates heat), so it depends on the cells geometry and ability to shed heat versus the reaction rate (pity the Sandia paper did't have more on that). But the runaway temperature for LiFePO4 is over 500F (ref). I doubt you can get the reaction to proceed that quickly in normal circumstances due to the relatively slow speed of ions across the electrolyte versus the battery's mass and surface area. Maybe in space where the vacuum could prevent heat transfer?

Someone must have done it to know that temperature... probably like NASA did using an external heater (ref). I suppose if the cells were in a car fire it could happen if the cell was made of materials that didn't melt before that. Ah, here's a paper where they got a LiFePO4 to enter thermal runaway, but it was a hotbox test.

If the battery were physically damaged or had impurities... then I'm not so sure. Say a nearly bad battery snaps and makes a resistance short through itself. If connected in parallel the other batteries would drain through the damaged cell; possibly heating the core of the damaged cell beyond 500? Are there side reactions that could catch it on fire? Don't know that it's absolutely impossible; but with cell fusing even that couldn't be an issue.

Update: In general, the oxygen looks to be too tightly bound for combustion even in thermal run-away. The most common fires associated with LiFePO4 seem to be caused by sparks from something striking across the terminals that cause something nearby to combust.

 

[offgriddle]

I responded to a house electrical panel fire as an electrician. The ground to the electricial panel was gone which caused one of the screws that mounted the circuit breaker panel cabinet to a wooden two by four wall stud to become hot enough to catch the stud on fire. ~ The moral is, even though Dr.Will's shared industry research has convinced me that lifepo is particularly well designed to be non self combusting, I will still make sure that my batteries and associated equipment are operated within equipment and wiring rating, installed with proper grounding, fusing/breakering, ventilation, spacing for heat disapation and in minimally combusting environments.

 

[Supervstech]

I responded to a house electrical panel fire as an electrician. The ground to the electricial panel was gone which caused one of the screws that mounted the circuit breaker panel cabinet to a wooden two by four wall stud to become hot enough to catch the stud on fire. ~ The moral is, even though Dr.Will's shared industry research has convinced me that lifepo is particularly well designed to be non self combusting, I will still make sure that my batteries and associated equipment are operated within equipment and wiring rating, installed with proper grounding, fusing/breakering, ventilation, spacing for heat disapation and in minimally combusting environments.

Wow... that is a wild circumstance... I’m imagining the scenario... that would heat the panel bonding... wild.

 

[offgriddle]

Wow... that is a wild circumstance... I’m imagining the scenario... that would heat the panel bonding... wild.

you know superV, good tekky's try to be aware of and cover all possible scenerios that affect safety and reliability and those who do their homework, pay attention, focus and apply knowledge and skill, manage to perform incredibly safe and brilliant work. When it comes to electricial theory and practice, while much is known, the unforseen and unknown still rears It's sometimes ugly head every now and then! I try to share what I know to be true and accurate on hopes of helping others. Peace

 

[BoloMKXXVIII]

I have seen test video where they have been massively over charged. They did swell up, breaking the case, then vent some rather evil looking gas, but they did not combust. I would be more worried about a short circuit or under gauged wire causing a fire.

 

[A J]

Are these Cells tampered with in any way to make this happen!
IE drill a small hole inject water or to the likes plug the hole and charge/use?
That's very possible, or abusing the poor cell to that point?
From what I've seen I agree with will, is any thing possible with these cells or dose it come down to manufacturer!

 

[A J]

Will I found this page with a mention of a runaway..
Lithium Battery Banks – Fundamentals
In order to reach thermal runaway and a battery fire with LiFePO4 chemistry, the oxygen held within the iron phosphate material needs to be released. Unlike with other lithium compositions, this is extremely difficult to achieve and requires very high temperatures to be reached. There have been many instances of inadequately installed LiFePO4 cells that overheated and caused great concerns about a possible fire, but none that actually ignited and burned yet on marine vessels – as far as I am aware of, at the time of writing.
And Cell Failures.. Have a read?

 

[Will Prowse]

Will I found this page with a mention of a runaway..
Lithium Battery Banks – Fundamentals
In order to reach thermal runaway and a battery fire with LiFePO4 chemistry, the oxygen held within the iron phosphate material needs to be released. Unlike with other lithium compositions, this is extremely difficult to achieve and requires very high temperatures to be reached. There have been many instances of inadequately installed LiFePO4 cells that overheated and caused great concerns about a possible fire, but none that actually ignited and burned yet on marine vessels – as far as I am aware of, at the time of writing.
And Cell Failures.. Have a read?

That picture doesn't show the actual cells catching on fire. How in the world did they pull that off? How did they hit the ignition temperature? If you have that much heat present, you can burn nearly anything. And considering the ignition temperature, it still is not self sustaining. And going by my graph above, thermal runaway STILL wouldn't occur even at 450 degrees.

That picture doesn't show proof of it being over charged and causing combustion at all. Its just a picture of a car that caught on fire. I need more evidence or a video. I cant see any batteries, or how they wired it, or if there were combustible materials nearby. I do not see it as compelling evidence of anything to be quite frank.

 

[Will Prowse]

Are these Cells tampered with in any way to make this happen!
IE drill a small hole inject water or to the likes plug the hole and charge/use?
That's very possible, or abusing the poor cell to that point?
From what I've seen I agree with will, is any thing possible with these cells or dose it come down to manufacturer!

Yes you can drill a hole in LTO or LiFePO4 and its fine. LiFePO4 will vent like crazy, but thats all. No fire. Lots of videos of this online.

 

[A J]

You are right. I thought it was worthy of your eyes, Sorry for the page of speculation.

Yes you can drill a hole in LTO or LiFePO4 and its fine. LiFePO4 will vent like crazy, but thats all. No fire. Lots of videos of this online.

Adding a substance in the drilled hole plug it, to make it catch fire "tamper", is any thing possible with these cells or dose it come down to manufacturer, think you missed the point on my statement.
Sorry if I misled you.

 

[Wiley]

Will, you said it could drill a hole in it and it will be fine...Hummm, if the battery is venting some sort of gas isn't there some point wherein loss of the material causing the gas going to cause changes/degradation of the chemistry within the battery? A big point of investing in these batteries is their long life. It seems to me that if the venting was a good thing (as in stopping the swelling) that the manufacturer's would make some sort of provision for such venting. And the vented gas, is it caustic or poisonous? Flammable or explosive like hydrogen (given off from lead acid) is only one aspect, causing massive corrosion to surrounding equipment or a poisonous atmosphere (carcinogenic?) is quite another. And if the gas is problematic, then having a securely sealed battery is important, so a cracked (as in dropped) battery is a discard?
This may be a bit off topic because it pertains to lithium Ion batteries, but the local shop that has a bin for people to toss their old dead batteries (and where I was getting "dead" 40 volt li-ion batteries and salvaging out the still useable 18650s) removed the bin. Why I asked? Well the local police came in and advised that certain young people were collecting such batteries, breaking them open, heating the contents and huffing (inhaling) the gas that came off in an attempt to get high. Sounds crazy but that is what the manager told me (and I've known him for over ten years) and they determined that they didn't want any responsibility in being part of the issue. Recycle bin is gone.

 

[dcaulton]

Will, after looking into the winter storage question, it's pretty clear that one bad event would be CHARGING THEM BELOW 32 degrees F. Apparently you get some crystals that pierce the internals and can theoretically cause really bad issues.

 

[Will Prowse]

Will, after looking into the winter storage question, it's pretty clear that one bad event would be CHARGING THEM BELOW 32 degrees F. Apparently you get some crystals that pierce the internals and can theoretically cause really bad issues.

Absolutely, that's why we have low temp cut off systems in our BMS. And it will not cause internal combustion even after you charge while freezing.

 

[dcaulton]

Absolutely, that's why we have low temp cut off systems in our BMS. And it will not cause internal combustion even after you charge while freezing.

yeah the consequences of this disaster are vague. I suppose it wouldn't cause a fire, just a dead battery.

 

[Pskel]

This happened to me a few days ago after a year of zero issues in my van. It literally exploded with audible explosion. No open flames but it was bad. Only one cell was damaged and BMS measured ~3.4v when it happened.

 

[Pskel]

 

[Short_Shot]

He asked for evidence of them starting on fire.

Yours did not start on fire.

 

[upnorthandpersonal]

Will, after looking into the winter storage question, it's pretty clear that one bad event would be CHARGING THEM BELOW 32 degrees F. Apparently you get some crystals that pierce the internals and can theoretically cause really bad issues.

Yes, but I've been trying that:

My conclusion (at this temperature range anyway) is that under normal circumstances you won't even be able to charge the cell because the internal resistance gets so high that you can't get current into the cell in the first place (at normal charging voltages).

@Will Prowse As far as I know, there is no way (except in lab set-ups that specifically are designed for it) to have a thermal runaway event with LiFePO4. You can get your electrolyte to vent, and that can be ignited if there is an ignition source, but this completely different than a thermal runaway combustion.

 

[Short_Shot]

Yes, but I've been trying that:

My conclusion (at this temperature range anyway) is that under normal circumstances you won't even be able to charge the cell because the internal resistance gets so high that you can't get current into the cell in the first place (at normal charging voltages).

@Will Prowse As far as I know, there is no way (except in lab set-ups that specifically are designed for it) to have a thermal runaway event with LiFePO4. You can get your electrolyte to vent, and that can be ignited if there is an ignition source, but this completely different than a thermal runaway combustion.

Nice video, but this thread is nearly 3 years old lol