Lithium fire protection

[nfbr]

LiFePO4 seems much less fire prone, but still provably vulnerable.

https://www.youtube.com/watch?v=uLzPSN8iagk

Three ideas for protection on a fibreglass (plastic) boat

1. Stainless Box - Boeing found that on 787 with a lithium fire things were "not good" unless battery was in a metal box with a vent. Preferably separating each battery in it's own box, with some insulation.

2. Water - The standard procedure for a lithium fire is water. Lots of water. If the battery is in a metal box, that will hold some water. If a thin wall black poly pipe was run though the top of the box, with a 20L reservoir above, a fire / overheat would melt the poly dumping 20L of water into the battery box.

3. Gyprock / Plasterboard. 2-3 layers of plasterboard is standard building firewall, as the material adsorbs signifiant heat as the gypsum decomposes.
https://www.sciencedirect.com/scienc...14398X16300103
This would adsorb significant heat and slow propagation between batteries.

[mickt243]

#2 is wrong, very wrong.

Lithium plus water leads to a very violent reaction.

To extinguish a lithium fire requires very specific extinguishing agents. AB(e) rated dry chemical powder extinguishers might help. Specialist agents like purple k, copper powder ect need to be matched to the battery chemistry.

#1 is specific to lithium cobalt oxide batteries on large aircraft in a particular load/charge profile.

[CharlieJ]

@nfbr
The recommendation to use copious amounts of water to cool A burning LFP battery or bank is absolutely correct. The goal is to cool the contents to mitigate the heat generated by the chemical reaction known as thermal runaway. There is very little Li used in the manufacturer of LFP cells so the specter of a chunk of Li in water going exothermic and being inextinguishable is not applicable.

Note that most of the electrolytes used in LFP batteries are flammable. Couple that with the exothermic reaction that occurs as a result of thermal runaway, and the owner is presented with a significant challenge. Further, venting of the products of combustion compounds the challenge.

References:
> MSDS from several LFP manufacturers.
> NFPA Hazard Assessment of Lithium Ion Battery Energy Storage Systems; 2016

[GordMay]

Originally Posted by mickt243

... Lithium plus water leads to a very violent reaction...

As Charlie noted, there is no free lithium metal within a Lithium-ion battery, including Lithium Iron Phosphate (LiFePO4).

[nfbr]

https://youtu.be/vS6KA_Si-m8

https://youtu.be/NeaK9V69Xks

https://www.bloomberg.com/news/artic...bout-fiery-evs

[nfbr]

https://www.tesla.com/sites/default/...e_Guide_en.pdf

[CharlieJ]

@nfbr
Although the fire extinguisher in the first YouTube film initially knocked down the visible flame, I have no doubt that the laptop battery would very quickly reflash because of the exothermic reaction.

In Europe, part of the protocol for fires in electric vehicles is to place the entire vehicle in a construction skip box full of water.

[john61ct]

IMO prevention is a much more relevant and productive line of inquiry.

For propulsion usage, tolerating some internally generated temperature rise may be required.

Maybe high-current short term usage like windlass, thruster, winch, watermaker, but these should usually be supported by high-amp ICE energy input.

But temperature rise should simply not happen in normal House bank use cases.

So detecting anything significant could trigger a cutoff, just as with the usual HVC, followed by an investigation as to the cause.

If anyone bothers digging into the details of that first video, I'd be interested in a summary as to how they stimulated that degree of thermal runaway.

Personally I doubt it's of much concern IRL.

[nfbr]

Originally Posted by john61ct

IMO prevention is a much more relevant and productive line of inquiry.

For propulsion usage, tolerating some internally generated temperature rise may be required.

Maybe high-current short term usage like windlass, thruster, winch, watermaker, but these should usually be supported by high-amp ICE energy input.

But temperature rise should simply not happen in normal House bank use cases.

So detecting anything significant could trigger a cutoff, just as with the usual HVC, followed by an investigation as to the cause.

If anyone bothers digging into the details of that first video, I'd be interested in a summary as to how they stimulated that degree of thermal runaway.

Personally I doubt it's of much concern IRL.

Says in the video, forced by gas flame

Membrane puncture / fault / dendrite can also give runaway, though big debates on LiFePO4 being safe
Assuming you are off the boat and it goes wrong...
20l of fresh water should stop it progressing

[nfbr]

If my math is right, 1.2kw batt can evaporate 2L of water to steam. 20L is plenty to keep one battery wet.

[mickt243]

Hmmm.... back when I was working in/managing an aircraft battery facility, some of the units we serviced were “lithium” (early 2000’s, most likely LCO) - they had their own seperate bay, only one was allowed in at a time, and if it showed signs of overheat the procedure was to hit the emergency shutdown and evacuate, if flames were visible a fire resistant suit and special respirator were to be used to apply the fire extinguisher that had a very long applicator wand (maybe 2 meters?) - we could only service one battery at a go because we only had the one extinguisher.....

Fairly sure our extinguisher was the powdered copper type - I always wondered what it would look like in use on a real battery fire, as it would be certain to short out all the cells potentially causing further thermal runaway (in cells that may have otherwise survived?) plus that lovely blue flame you get from copper plus fire....

[nfbr]

Originally Posted by mickt243

Hmmm.... back when I was working in/managing an aircraft battery facility, some of the units we serviced were “lithium” (early 2000’s, most likely LCO) - they had their own seperate bay, only one was allowed in at a time, and if it showed signs of overheat the procedure was to hit the emergency shutdown and evacuate, if flames were visible a fire resistant suit and special respirator were to be used to apply the fire extinguisher that had a very long applicator wand (maybe 2 meters?) - we could only service one battery at a go because we only had the one extinguisher.....

Fairly sure our extinguisher was the powdered copper type - I always wondered what it would look like in use on a real battery fire, as it would be certain to short out all the cells potentially causing further thermal runaway (in cells that may have otherwise survived?) plus that lovely blue flame you get from copper plus fire....

Correct. Same as EPIRB. Not rechargeable.
Don’t confuse Lithium Metal (primary, not rechargeable) with Lithium Ion (secondary, rechargeable)

[john61ct]

Originally Posted by nfbr

Membrane puncture / fault / dendrite can also give runaway, though big debates on LiFePO4 being safe

No, any debate IMO is just fear mongering

Can put bullets through them, no flame

[GordMay]

Originally Posted by nfbr

... Don’t confuse Lithium Metal (primary, not rechargeable) with Lithium Ion (secondary, rechargeable)

Indeed.
And don't confuse LiFePO4 with other Li-ion chemistries.
"SAFETY OF RELiON® LITHIUM IRON PHOSPHATE (LiFePO4, sometimes LFP) BATTERIES"
“... The main cause of fire or explosion of a lithium ion battery is excessive overheating during charging, which causes a perpetuating reaction called thermal runaway. Without proper management, thermal runaway may result in fire. The initial source of this excessive heat is the instability of most lithium ion chemistries. RELiON uses lithium iron phosphate (LiFePO4), which is an inherently safe chemistry. The structural stability of LiFePO4 results in significantly less heat generation compared to other lithium chemistries ...”
➥ https://relionbattery.com/uploads/im...iumBattery.pdf

[noelex 77]

There is a good recent article by Nigel Calder on lithium batteries. He discusses the safety of LFP and the risk of fire. I think I originally read this in Sail magazine but you can read it free here:

https://www.pressreader.com/usa/sail...81616716235445