What's the best method to put out an ebike battery fire?

[Joseph C.]

Without an extinguisher - Sand is the next best ticket to remove the burning metal from contact with air.

I wonder if the grain size is important to safety. If the sand is too fine would there not be a danger of it making the situation worse by possibly igniting violently?

 

[dnmun]

high currents during charging are not as safe as low currents.

the sand is irrelevant, there is flame only because the cells are so hot they ignite the surrounding plastic stuff. you have to cool it rapidly with water to prevent it from causing fire. cool it is all you can do until the energy stored in the electrodes has been exhausted.

i still think it woulda helped to cut the wire on that battery when it shorted. but it has to be done immediately which is why i thought just breaking the cap off to get access to the wiring was relevant.

 

[Kingfish]

Without an extinguisher - Sand is the next best ticket to remove the burning metal from contact with air.

I wonder if the grain size is important to safety. If the sand is too fine would there not be a danger of it making the situation worse by possibly igniting violently?

Huh?
Moderately fine sand is good enough. If it’s D.G. (Decomposed Granite), well – yes the grain size would likely be less effective than say Prime Florida Real Estate, but that’s just an educated guess. :wink:

Sand is primarily composed of silica… of silicon, and is a wonderful ingredient in refractory bricks used to line boilers, fireplaces, and chimneys. It’s durable hard shit that can take a beating, which is also why it’s a dang good ingredient for sandpaper and grinding wheels.

Metal fires are not something to play about with; a few metals in pure form create their own oxygen once they get started, such as Magnesium: If placed on a steel deck, it will burn through the plate and the ones after that until the material is completely spent. You also do not want to put water on it cos it will convert it to Hydrogen! If the heat of combustion is high enough, it will fuse sand into glass… sort of like thermonuclear bombs and Chernobyl. However I think that a burning Lithium battery poses slightly less of a threat. I’d use metal tongs – like for handling fireplace logs – and grab the battery and drop it into a bucket lined with sand at the bottom, cover it with more sand to bury it, then find a place away from humans to dispose of it, or for it to completely burn out.

To conclude: Generally, putting out metal fires with water is a bad idea. Lithium batteries are not pure metal Lithium per se, so there is some margin to play with. Sand and Dry Extinguishers are preferred. Baking Soda is cheap. I think sand is cheaper. Know your poison and pick out the proper cure for when it bites.

~KF

 

[liveforphysics]

Lithium fires are of a type called Class-D for Combustible Metals. Dry extinguishers are preferred; if that is not available then have a bucket of sand ready. In the Navy, we could drop burning metal into a stout bucket with a layer of sand and toss it over the side. Without an extinguisher - Sand is the next best ticket to remove the burning metal from contact with air.

A list of Class D extinguishers is found here on Wikipedia.

~KF

There is no Lithium burning in our batteries. There is not even any metalic Lithium in our rechargeable lithium batteries we use in ebikes. There is no combustion of metals in our ebike battery fires. A loosely bonded metal oxide compound exceeds decomposition temperature, liberates oxygen and this oxygen reacts with the solvents and separator materials in an impressive rush of flame in extreme cases, or a smoldering partially oxidized white smoke in mild cases (except in the case of non-pouch cells, where they can build pressure and explode violently when the "vents" fail to open).

Currently, my thoughts are:
1) Use high quality batteries from reputable suppliers (I typically use Panasonic CGR18650CG cells) but good suppliers won't do custom things so sometimes there is a need to use other untested companies. Definitely can't recommend typical Chinese suppliers after this morning's excitement.

This wasn't a cell failure, it was a pack failure (internal wiring short, BMS short, insulation failure between tab welds can can, etc etc). Using the worlds best LiCoO2 premium laptop cell or the worlds most sketchy re-shrink-wrapped 10 year old recycled laptop ultra-fire cell would likely have made no difference in the outcome.

if using a shovel to move the overheated battery shell is not possible, then use thick leather gloves to remove it manually from the rack and have a small 2 gallon metal pail to place it in to carry outside. leather is effective at blocking a a lot of the heat and does not melt like rubber coated work gloves. keep large size diagonal cutters or lineman's pliers close by and cut all wires that you can reach and cannot unplug because they have melted together, especially if it is connected to a charger, as it would most likely be if it catches on fire.

This is some capitally poor advise. The separator is a flouropolymer being oxidized and emitting various fluorine compounds in combustion. I think I permanently scared my lungs and sinus passages from being exposed to the combustion gasses a number of times. It would be possible to die from a single poorly timed breath while trying to carry a battery in a bucket outdoors somewhere, not to mention, with 18650 fires you're in a serious danger to be close enough to be carrying a bucket, and in many pouch cell fires I've experienced, you could be burned fatally from the eruption of intense asphalt melting pillars of flame that can erupt a minute or two after it was just sitting and mildly smoking.

the sand is irrelevant, there is flame only because the cells are so hot they ignite the surrounding plastic stuff. you have to cool it rapidly with water to prevent it from causing fire. cool it is all you can do until the energy stored in the electrodes has been exhausted.

The sand functions by having a very large latent heat of fusion. The sands function is not to act a a smothering oxygen blocker as in a traditional fire (which is how it extinguishes most burning materials, wood, metals, plastic, etc), but rather as a thermal energy sink. Cells vent multi-thousand degree flames into sand, and sand allows the hot combustion gasses to move into it and absorb the energy in the form of melting the sand, and by melting the sand, acting as a massive energy sink that directs the reactions energy into making globs of dirty glass rather than destroying the things around it. It's not going to stop materials in the battery at the 02 liberation temperatures from further decomp and reaction with the separator and solvents etc, but it can absorb that energy to avoid it damaging things around it, and sometimes prevent it from spreading to adjacent cells.


Your personal life safety should take priority in the event of a battery fire. Get away from it an into clean air to breath.

If you want to be a hero and are willing to risk your health, hold your breath and just try to roll the bike to somewhere the fire is unlikely to spread (outdoors, concrete floor, etc).

 

[Hillhater]

...There is no Lithium burning in our batteries. There is not even any metalic Lithium in our rechargeable lithium batteries we use in ebikes. There is no combustion of metals in our ebike battery fires. A loosely bonded metal oxide compound exceeds decomposition temperature, liberates oxygen and this oxygen reacts with the solvents and separator materials in an impressive rush of flame in extreme cases, or a smoldering partially oxidized white smoke in mild cases

So we are dealing with a "chemical" fire, then Luke ?

I still think Lowracers garbage can of water was very effective.
I hate to imagine what 3kWhr of lipo fire would look like with no suppression !
...and it would have needed a big pile of sand !

 

[liveforphysics]

...There is no Lithium burning in our batteries. There is not even any metalic Lithium in our rechargeable lithium batteries we use in ebikes. There is no combustion of metals in our ebike battery fires. A loosely bonded metal oxide compound exceeds decomposition temperature, liberates oxygen and this oxygen reacts with the solvents and separator materials in an impressive rush of flame in extreme cases, or a smoldering partially oxidized white smoke in mild cases

So we are dealing with a "chemical" fire, then Luke ?

I still think Lowracers garbage can of water was very effective.
I hate to imagine what 3kWhr of lipo fire would look like with no suppression !
...and it would have needed a big pile of sand !

If you can cool it down (with water, sand, etc), it tends to slow the reaction. Most times water helps, I've had one time water reacted and caused some kind of bizarre exothermic event that just billowed tons of noxious oily solvent fumes, but fortunately showed no fire/flames etc, as my unprotected face was just an arm's length away. This was from a cell that had dead-shorted from fully charged to 0v and was extremely hot and badly puffed. Normally cells charged, slashed open, and tossed in water just evolve some tiny bubbles with a non-offensive odor that look similar to champagne.(May just be browns gas from the expected electrolysis effects and unrelated to any chemical reactions occurring)

I've also seen a shorted 18650 that got hot enough to melt it's shrinkwrap into shreds around the can just violently explode with shrapnel the instant the stream from the garden hose hit it, after I had waited about 10mins and given up on it doing anything cool. I'm guessing the case was under huge internal pressure stresses, and the local contraction of the metal at the point the water hit it was enough of a stress-riser to give it a point to rupture from it's internal pressure.


Again though, priority #1 should be making sure any humans in breathing range of a battery venting/burning etc get away and to safe fresh air. Hydrodgen flouride gas evolved once the thermal event start occuring. This is not a gas you want to be breathing, I think my lungs have been scared inside from the Hydro Flouric acid it produces instantly upon contact with any moist surface. Just a bit of the gas passing over your eyes is enough to need a new set of corneas if you're still into being able to see.

For myself, if I was working on my bike indoors, and for whatever reason the battery started to smoke/vent just a tiny bit, I would try to take a clean breath of air, hold my breath, squint my eyes and try to push the bike outside as fast as possible, I could see myself throwing it through a window if that was the fastest method. If it started to violently billow smoke, I would get the hell away from it, and scream for anyone else around to get outside to clean air.

In GM's battery lab, they had an A123 pack start to burn in a proper test chamber with proper rated fire suppression systems, by the time they decided to bail, 5 guys ended up in the hospital.

You guys know I'm not a safety ninny. However, while nearly painless at the time HF in your lungs and eyes is no joke.

 

[TheBeastie]

For no apparent reason, a lithium ion (36V 12Ah) tube battery I was testing from a little known Chinese supplier came to a smoking and flaming end.

So putting a side that it was most likely a bad internal wiring job etc over it being the "cells" fault etc, what kind of cell chemistry exactly was it?
Was it the popular "Lithium Iron Phosphate LiFePO4"?
Or the other one I am seeing a lot of on ebike shop sites "Lithium (NCM) Nickel Cobalt Manganese - Li NiCoMn" ?
Or something else?

Thanks!

 

[Ykick]

Thanks for the great advice Luke!

 

[redstone02]

...
In GM's battery lab, they had an A123 pack start to burn in a proper test chamber with proper rated fire suppression systems, by the time they decided to bail, 5 guys ended up in the hospital.

You guys know I'm not a safety ninny. However, while nearly painless at the time HF in your lungs and eyes is no joke.

I was drafting a post for advice on wiring four 6sp1 LiPo's into one 12s2p:
LiPo looked like the promised land; high C-rate, low voltage drop… low internal resistance, small light weight pkg. Until I started researching all the safety considerations/equipment, now LiPo is on the titter-totter. LiPo’s scare the hell out of me. Do not have a fireplace. Do not have a shed or workshop. Do not have an old refrigerator. With incomplete combustion, HF (I understand) is in the mix of an exothermic LiPo run away. HF is not to be taken lightly. I have a couple of 7.62 mm NATO ammo cans for chargin’. The thing in mind now is venting the ammo cans to the exterior of my apartment through a steel (not AL) flexible muffler pipe to a window.
Anyone using ammo cans with flexable muffler pipe to vent to exterior?