Theoretical lipo fire. What would happen...?

[peters]

Lithium is hazardous. We can apply proper charge-discharge procedures to prevent fire, but it is not 100% secure. What kind of protection is required to ensure that lithium fire will not endanger anything outside the battery pack that is built into a bike or other vehicle?
Specifically I'm interested in what would happen if an approx. 2kWh lipo or other lithium battery ignites in a closed metal box, like a Stealth or Qulbix or Vector bike frame, and I prefer to discuss instead of trying.

Some outcomes I think of, but not sure which one is probable:
- can high enough internal pressure develop that frame explodes? Is the high pressure a realistic problem?
- the frame heats up very much and combustible materials outside the frame ignite, starting from the plastic paint of the frame, then the other parts around?
- can the frame melt (aluminum or steel) due to concentrated heat, then fire gets out of the box?
- the small amount of air getting inside the frame through the slots (e.g. charger connector) is enough to maintain the fire inside and the flames get out?
- fire is extinguished in the absence of oxygen, there is just some heating up and the outside temperature remains relatively safe, e.g. below 100°C?

What is the realistic scenario?
What would be the safe protection? For example non-flammable or thermally insulated casing of the pack with a pressure-sensitive valve outlet would be needed?

 

[Nobuo]

- can high enough internal pressure develop that frame explodes? Is the high pressure a realistic problem?
- the frame heats up very much and combustible materials outside the frame ignite, starting from the plastic paint of the frame, then the other parts around?
- can the frame melt (aluminum or steel) due to concentrated heat, then fire gets out of the box?
- the small amount of air getting inside the frame through the slots (e.g. charger connector) is enough to maintain the fire inside and the flames get out?
- fire is extinguished in the absence of oxygen, there is just some heating up and the outside temperature remains relatively safe, e.g. below 100°C?

What is the realistic scenario?
What would be the safe protection? For example non-flammable or thermally insulated casing of the pack with a pressure-sensitive valve outlet would be needed?

- sure, all the encapsulating-oriented protection would exchange flames for explosion.

- 99% of the combustion would came actually from the battery, there are not much flamable materials on a standard ebike, and can't be compared from the energy generated from the combustion of the cells.

- very difficult, smoking and breaking parts is the common, but everything not metal-made will burn or melt

- yes, lithium will have a violent hot reaction and will come searching oxigen, if you make hard for the lithium to reach oxygen, then a explosion is more probable.

- A battery can't be made in completely vacuum, oxygen will be always there.

The safest protection is to use a non-flamable or almost non flamable chemistries like LiFePo4 or NCA lithium-ion cells. charge the battery always attending it, never at night, a fire extinguisher at hand and a removable battery would help avoid a disaster too

 

[dogman dan]

Vent the box, not toward your balls though.

Sure, it might not have oxygen to belch fire in the sealed box, but rapidly expanding gasses in a tight container is worse than fire.

How big a hole do you need? Depends on the event. I saw one where the open top of a coffee can was too small a vent. My lipo storage is ammo cans, with several half inch holes drilled. I do not lock down the tops!!! I do hope an event will be directed into the fireplace, if it does happen slow enough. Otherwise, the tops will pop open.

This is routine for flammables storage. My wife works in that field, the flam store shed always has a roof that will blow off first in an event. And walls that will not let flying metal through. So better to shoot the roof sky high, than send shrapnel through the parking lot, if the 55 gallon drum of acetone, or alcohol goes off.

What about 18650 cells in the little cans? They have a vent that pops if the cell puffs inside the can.

 

[motomech]

Lithium is hazardous. We can apply proper charge-discharge procedures to prevent fire, but it is not 100% secure. What kind of protection is required to ensure that lithium fire will not endanger anything outside the battery pack that is built into a bike or other vehicle?
Specifically I'm interested in what would happen if an approx. 2kWh lipo or other lithium battery ignites in a closed metal box, like a Stealth or Qulbix or Vector bike frame, and I prefer to discuss instead of trying.

Some outcomes I think of, but not sure which one is probable:
- can high enough internal pressure develop that frame explodes? Is the high pressure a realistic problem?
- the frame heats up very much and combustible materials outside the frame ignite, starting from the plastic paint of the frame, then the other parts around?
- can the frame melt (aluminum or steel) due to concentrated heat, then fire gets out of the box?
- the small amount of air getting inside the frame through the slots (e.g. charger connector) is enough to maintain the fire inside and the flames get out?
- fire is extinguished in the absence of oxygen, there is just some heating up and the outside temperature remains relatively safe, e.g. below 100°C?

What is the realistic scenario?
What would be the safe protection? For example non-flammable or thermally insulated casing of the pack with a pressure-sensitive valve outlet would be needed?

100s of members here use Lipo on a daily basis without encapsulating the packs in some kind explosion proof case and I dont recall anyone going up in flames.
I have inadvetently punctured a Lipo cell and it didn't ¨blow up¨. It just glowed orange and hot inside the pouch.

 

[wesnewell]

If one cell ignites within a tight closed space, more than likely they will all go up in flames in a cascading fashion. Same thing would probably happen even in open air, just take longer for adjoining cells to ignite. I'll let you know if I ever have a cell catch fire. Might be a while though. I've never ever had one smoke in over 4 years and 15K miles.

 

[999zip999]

After a explosion and fireball a battery fire has a black smoke that attaches to everything it almost impossible to remove. so after a battery fire the smoke residue coats and destroys most things. So inside a garage or workshop everything will get a coat of special black soot that has to be sanded off. A mess. All batteries have a fire potential.

 

[peters]

100s of members here use Lipo on a daily basis without encapsulating the packs in some kind explosion proof case and I dont recall anyone going up in flames.
I have inadvetently punctured a Lipo cell and it didn't ¨blow up¨. It just glowed orange and hot inside the pouch.

There were many cases:
http://endless-sphere.com/forums/viewtopic.php?f=14&t=56305
http://endless-sphere.com/forums/viewtopic.php?f=14&t=47012
http://www.endless-sphere.com/w/index.php/Battery_safety
LiFePO4 is the safest, but for any type some kind of protection is need to my mind, especially it should be expected from vehicle manufacturers.

 

[dnmun]

no, there is no case here where a lipo pack has caught on fire in use. there is only one case reported here of a fire, which was caused by a failure of a BC 168 balancing charger that overcharged one cell in a pack and caused a fire while charging.

lipo does not explode. it does not spontaneously catch on fire unless it is overheated to the critical temperature where it can go into thermal runaway.

lifepo4 will also go into thermal runaway at a higher temperature than lipo but lipo seems to create the most heat energy when overcharged and lifepo4 seems to just die when overcharged so it does not reach the critical temperature to go into thermal runaway as easily as does the lipo.

you can short out the lipo packs and if it gets hot enuff then it will go into thermal runaway too.

in all cases where you have a lipo pack on fire then immediately immerse it in a bucket of water.

that will cool it off so the thermal runaway is terminated and it blocks the introduction of oxygen to the flaming solvents in the electrolyte.

 

[alexis57]

in all cases where you have a lipo pack on fire then immediately immerse it in a bucket of water.

Is it really a good idea ? every cells will be shortcut...

 

[999zip999]

I thought greenmachine had a lipo fire on his girlfriend bike in San Francisco park.

 

[docnjoj]

Hi Zip. IIRC green's GF fire was LiFePO4.
otherDoc

 

[dnmun]

Hi Zip. IIRC green's GF fire was LiFePO4.
otherDoc

chroot's fire was headway pack that shorted while charging and it caught the nylon bag on fire but none of the headway cells overheated and vented.

i am fairly certain that floont's lipo fire was from his use of the big meanwell chargers on his 35S lipo pack because he had stated beforehand that he intended to charge it without a BMS but he has never posted here since then or told us what he was doing, just that he had burned down the house and garage. all to save a few bucks on the BMS.

 

[amberwolf]

in all cases where you have a lipo pack on fire then immediately immerse it in a bucket of water.

Is it really a good idea ? every cells will be shortcut...

Does it matter? It's already on fire, what could possibly make it worse? :lol:

 

[alexis57]

Does it matter? It's already on fire, what could possibly make it worse? :lol:

Haha true, but we must have a bucket of water during the lipo is burning haha
(it'll take too much time to fill a sink or something else)

Anyway, Lipo are everywhere (smartphone/your pocket, laptop, gps, watches, camera etc...) without any problems.
If they catch in fire, it's 99% because of the user. (not using BMS, bad charger, incorrectly set the charger, shortcut etc...)

 

[amberwolf]

Haha true, but we must have a bucket of water during the lipo is burning haha
(it'll take too much time to fill a sink or something else)

That's waht being prepared for a fire is all about. If you aren't prepared for a fire (of wahtever type) it will get out of your control very fast, and then all you can do is watch and wait for the big trucks to get there to help you out...and by then it could be far too late to save what you wanted to save.

If you're right there, and you're prepared, you can probably stop it before it's a conflagration. If you're not there you can do nothing. But if you are there, and not prepared, you may still be able to do nothing, if it takes too long to get something to fight the fire with.

So...whatever you intend to do to stop a fire, of whatever kind, you need to do it in advance, and have it always ready.



(even if I had been home during my non-bike-related housefire, I might have been unable to do anything to stop it because I wasn't all that prepared for any kind of fire, but I would have been able to save the dogs.... But since I wasnt' there, I could do nothing at all. If I'd been there with proper fire preparations, like good fire extinguishers (I had several, but most were old and possibly not working well if at all, needing recharge) I could probably have stopped the fire before it had done any serious damage).

 

[alexis57]

I thought just use a trashcan in metal or a metal case.
I found a video, it seems to be useful.
https://www.youtube.com/watch?v=6M5ftkN9PtY
With a good resistant blanket, in case of fire, it should be good. (at least just for taking the case and put it outside)

It seems too much but it's really cheap and not constraining

And I chose XT60 connectors instead of XLR connectors in order to be able to disconnect quickly.

 

[amberwolf]

I thought just use a trashcan in metal or a metal case.

Sure; I keep my batteries in steel ammocans that have just a small vent on them to let pressure out in case of failure. The theory is that they can't get new oxygen in there so other than whatever is liberated during the chemical reactions inside the cells, but it is untested,

Probably won't be long till my RC packs presently in one of thsoe cans are ready to use as a destructive test; they're super-puffy already. :/

 

[dnmun]

just pour your water bottle on it. put the nozzle of the water where the flames exit the pack and squirt it into the pack so the water can flood the point of ignition and suppress the flames long enuff to allow the pouches to cool off.

if you are the type of person who instead of acting to put out the fire, stands around and takes pictures with your cellphone or posts up the picture on instagram because it is cool so you wanna show your facebook buddies then you really need to adjust your priorities.

i am always staggered by the people who just stand around and watch when accidents happen.

this pipeline rupture in santa barbara is a case in point where someone actually had smelled the oil fumes from the ruptured pipeline but did nothing to alert the pipeline people who were just a short distance away up the hill. just amazing and then they blame it all on the pipeline company and act like they are some evil horrible uncaring greedy buncha thugs. instead of some lazy ass wimp who could not be bothered to drive their fat car up the hill to tell them.

 

[alexis57]

dnmun: your message is to .... ?

I just hope this will work fore my 18650 pack ... 18650 fires are different than RC lipo fire.

 

[dnmun]

but the principal is the same. you need to reduce the temperature of the chemicals inside the can. if you get it down below the critical temperature by drawing off all the heat generated then the thermal runaway should cease.

 

[Hillhater]

no, there is no case here where a lipo pack has caught on fire in use. ...... .

..maybe not a forum member's fire, but why are you all overlooking the most famous , and most investigated, LiPo pack fire.??
http://endless-sphere.com/forums/viewtopic.php?f=14&t=46853&hilit=Dreamliner

 

[amberwolf]

no, there is no case here where a lipo pack has caught on fire in use.

SoSauty's doesn't count?

To be sure, it was caused by (AFAICR) plugging the packs into each other wrong, shorting them together, but it had to be removed from the bike whiel burning. Can't find the thread or post for it now, but it's probably buried in one of the racing threads.

Then there is Kepler's:
http://endless-sphere.com/forums/viewtopic.php?f=14&t=29256#p422039

BikeFanatic also had one while riding though I didn't look for the thread yet.

Greenmachine's friend had one while riding, too.

I can't remember all the others right now.


EDIT: the Catastrophic Events threads linked below also include some apparent impact damage fires, at least one while riding (by Wishes, I think) and at least one from a pack falling 90cm from a shelf.

In those cases, it is possible that a hard shell case would have prevented the damage and fire (perhaps not, if it was instead a wiring issue exacerbated by impact forces).

there is only one case reported here of a fire, which was caused by a failure of a BC 168 balancing charger that overcharged one cell in a pack and caused a fire while charging.

There are a number of other cases of RC LiPo fires, including John in CR's spontaneous fire of a single RC LiPo pack sitting on a table or desk not hooked to anything.

I don't remember the others just at the moment, so a little searching before I post.

I once did a list in the Wiki:
http://www.endless-sphere.com/w/index.php/Battery_safety
apparently some of those links are wrong, and point to unrelated threads. Gotta fix that when there's time. (anyone with the time is welcome to; it also needs to be edited to re-include the word "fire" that it was originally titled, because it doesn't come up in a search of the wiki!)
A search of just "fire*" in the Battery Technology subforum, only by topic and only in topic/thread title, finds these:
http://www.endless-sphere.com/forums/search.php?keywords=fire*&terms=all&author=&fid%5B%5D=14&sc=1&sf=titleonly&sk=t&sd=d&sr=topics&st=0&ch=300&t=0&submit=Search

One of those:
http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=46040&hilit=fire%2A#p671857
from 2012 has a list of some events (but no links)


There is also the two Catastrophic Events threads
http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=47012
http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=56305
that describe some events.

lipo does not explode. it does not spontaneously catch on fire unless it is overheated to the critical temperature where it can go into thermal runaway.

I won't argue about that, but there has been at least the one event in John in CR's guest house (hardcase pack, I think?) where it is unclear what could possibly have caused the fire if it was not spontaneously caused from within the pack itself (most likely contamination or impurity, from what some like Liveforphysics have said). No way to know for sure though.



FWIW, most of the incidents reported are during bulk charging, unattended. Some were in-use, while riding or while testing or troubleshooting the bike. Some were under other conditions.


I didn't look up fires for any other chemistry than RC LiPo, but there are some.

 

[dogman dan]

Response is better if you have some kind of a plan.

If my smoke alarm goes off,

1 grab phone and get out.
2 call 911.
3 open the door right by the fireplace where I store my lipo, get the house started venting.
4 if still possible with one held breath, use a flat shovel I have nearby to get that flaming pack out of the house.
5 if I get that far, start cooling the top of the room with water, from outside.
6 only if I get the house out and the dogs are ok, take video of the still burning lipo pack.

FWIW, I have put out a house on fire before. Did it with 2nd and 3 degree burns on me. You don't feel it till later.

 

[dnmun]

i have put out two house fires started by my tenants. the last one was a laptop charging on top of a down comforter on the bed. i think the tenant had wired up a different AC adapter to the wiring plug on his laptop so it was overcharged. i could see the spot where two different wires had been twisted together on the DC side.

i feel i was lucky in both instances because if i had not been there then i would have lost both houses. the first one was deliberately set i think by the tenant because i found out later he had a criminal court date set for that day and the police were looking for him that night when he did not appear in court.

 

[Ykick]

While very very rare I believe the most plausible explanation for bare/naked undisturbed RC Lipo going off is contamination or low voltage gassing followed by puffing/swelling physical deformation of the pouch.

In extreme situations (I’ve seen pouches that looked like balloons) the tabs could potentially touch and externally short circuit creating either a source of ignition spark and/or dangerously over-discharge cells below minimum voltage range.

It can be naughty stuff. I now mostly use it for relatively small 16S1P lightweight BMS equipped packs to help keep the flammable volume down while being much easier to monitor and install a BMS.

High C rate can cells will likely be in the near future for many of us…