Re: battery fire

On 19/01/2025 04:54, Bill Sloman wrote:

On 18/01/2025 9:37 pm, Liz Tuddenham wrote:

I seem to remember from my chemistry lessons that lithium reacts
violently with water.  Containing lithium pollution of large areas of
the sea in stormy conditions (which is when catastrophic failure is most
likely to occur) might be quite difficult.

Not that violent - it scuds around on the water surface fizzing but it takes quite a big piece to actually catch fire with a nice lilac flame.

It wasn't lithium but sodium. Potassium was even worse. Lithium does react in a similar way, but it schools didn't keep stocks of lithium metal around fifty years ago, and probably still don't.

Oh yes they did!
It was standard practice back then to demonstrate the progressively more violent reaction of lithium, sodium, potassium and if the school was very rich or teacher had friends in the chemical industry rubidium.
Likewise for chlorine, bromine and iodine.
Although I have seen fluorine made in a public lecture at UMIST back in the 1970's it would never be allowed today. A cauldron of molten anhydrous eutectic mix in one corner with long copper pipe up high. The first 5 minutes were spent on the evacuation procedure in case anything went wrong. You could smell fluoride of oxygen in the air afterwards!
https://fluorine.ch.man.ac.uk/history.php
https://en.wikipedia.org/wiki/Oxygen_fluoride

The standard technique for dealing with a lithium battery that has caught fire is to flood it with lots of water. Sea water contains about 0.17 ppm lithium, so lithium pollution isn't going to be a problem.

You need so much water to quench one that it isn't realistic for BESS container scale fires - you have to try and limit the spread to other modules.
If one starts to go in an iToy you have only about 15 seconds to get it out of the house from the moment that the dense white toxic smoke first appears. You really don't want to breathe the fumes or worse still heavy metal nano-particles in black smoke that get emitted usually just before it goes up in flames. Far too hot to handle well before then.
This academic from Newcastle is a world expert on Li battery fires :
https://www.youtube.com/watch?v=jby0uyL78YU
12 minutes in if you want to just see the flash bang nail demo.
Intended to brief first responders and firefighters to the real hidden dangers of Lithium battery fires. The whole thing is worth watching.
--
Martin Brown