Was sat in a friend's garden today when his solar-charging battery unit burst into a ferocious sustained jet of flame and gas about 2 foot long. Put a hole through a seat cushion in seconds it was sat on. On reflection, I was thinking what can be done in that event. You absolutely cannot stop the flame and it causes damage in seconds before you even realize what's going on. My friend knocked it on the floor to reduce the potential damage to the garden furniture we were sat on. Not sure it was a good idea to have pushed and dropped it on the floor because it might have exploded?

Appreciate your thoughts, and my lesson I got from it was "people first" and get out of the way asap, rather than trying to deal with it when the thermal runaway is in full flow. The first actual concern was the furniture, which on reflection was the wrong priority.

Edited May 20May 20 by StringJunky

Wow, it would be really difficult NOT to knock the unit off the chair as a first reaction. It's on fire, and you know the least of what will happen if you just run away without robbing the flame of at least some fuel. And I'm not sure it's the wrong reaction. If it doesn't explode right off the bat, I don't think a 2-foot drop will change the flame to a boom. I agree with the people first rule, but fires can harm people too. I think your friend did the right thing.

From my limited understanding of the constantly changing composition of Li-Ion batteries, the Lithium salts are in an organic electrolyte.
The Lithium is very reactive with water that may seep in through cracks in the casing developed during the winter months ( for outdoor lighting ) which will catch fire, produce Hydrogen gas, and ignite the electrolyte.
Obviously you don't want to put water on it, but a 'reactive metals', D-type fire extinguisher, or possibly even an ABC type, containing Ammonium Phosphate, might mitigate the risks associated with 'handling' such a fire.
I have kept two fire extinguishers in the house for the past 40 years ( since I started working with chemicals ), and fortunately, only had the opportunity to use one of them once.

1 minute ago, MigL said:

From my limited understanding of the constantly changing composition of Li-Ion batteries, the Lithium salts are in an organic electrolyte.
The Lithium is very reactive with water that may seep in through cracks in the casing developed during the winter months ( for outdoor lighting ) which will catch fire, produce Hydrogen gas, and ignite the electrolyte.
Obviously you don't want to put water on it, but a 'reactive metals', D-type fire extinguisher, or possibly even an ABC type, containing Ammonium Phosphate, might mitigate the risks associated with 'handling' such a fire.
I have kept two fire extinguishers in the house for the past 40 years ( since I started working with chemicals ), and fortunately, only had the opportunity to use one of them once.

My limited understanding is that at high temperatures some of the components actually evolve oxygen, so the thing cannot be smothered. The only way to stop it seems to be either to let it burn out somewhere where it can't damage anything else, or to use copious amounts of water, sufficient to cool it enough to stop the further evolution of oxygen. At least, that is what I have read somewhere the fire brigade tries to do.

P.S. I've relocated the piece I read about this, from the UK Fire Protection Association: https://www.thefpa.co.uk/advice-and-guidance/advice-and-guidance-articles/how-to-control-a-lithium-ion-battery-fire-

Edited May 20May 20 by exchemist

12 minutes ago, MigL said:

From my limited understanding of the constantly changing composition of Li-Ion batteries, the Lithium salts are in an organic electrolyte.
The Lithium is very reactive with water that may seep in through cracks in the casing developed during the winter months ( for outdoor lighting ) which will catch fire, produce Hydrogen gas, and ignite the electrolyte.
Obviously you don't want to put water on it, but a 'reactive metals', D-type fire extinguisher, or possibly even an ABC type, containing Ammonium Phosphate, might mitigate the risks associated with 'handling' such a fire.
I have kept two fire extinguishers in the house for the past 40 years ( since I started working with chemicals ), and fortunately, only had the opportunity to use one of them once.

Does it seem like dropping it to the ground or some other kind of impact could make it actually explode, as in the OP?

4 minutes ago, Phi for All said:

Does it seem like dropping it to the ground or some other kind of impact could make it actually explode, as in the OP?

I'd have thought anything that breaches containment of the electrolyte might well cause a very rapid flare-up, even if not technically an explosion.

Not sure.
The casing is there to isolate the volatile contents from the elements.
The drop and the heat of the fire might further break open the casing and intensify the ongoing reaction.

X-posted with Exchemist

Edited May 20May 20 by MigL

1 hour ago, exchemist said:

I'd have thought anything that breaches containment of the electrolyte might well cause a very rapid flare-up, even if not technically an explosion.

1 hour ago, MigL said:

Not sure.
The casing is there to isolate the volatile contents from the elements.
The drop and the heat of the fire might further break open the casing and intensify the ongoing reaction.

So, in the OP scenario, the best thing to do is let the chair burn and avoid a possible explosion. I think I'd still try to pick up the whole chair and put it somewhere it can't catch anything else on fire.

8 minutes ago, Phi for All said:

So, in the OP scenario, the best thing to do is let the chair burn and avoid a possible explosion. I think I'd still try to pick up the whole chair and put it somewhere it can't catch anything else on fire.

I’d think that reasonable so long as you did not throw or drop the thing suddenly. It seems to me one has to think in terms of something like a chip pan fire.

I do know cylindrical batteries have vents around the positive to release pressure in such an event. It has certainly made me think about the risk of such chemistry. Imagine a firework rocket held horizontally, that's how energetic it was.

Edited May 20May 20 by StringJunky

36 minutes ago, exchemist said:

I’d think that reasonable so long as you did not throw or drop the thing suddenly. It seems to me one has to think in terms of something like a chip pan fire.

I honestly don't think I'd be reasonable if this happened to me. 2-foot flame jets coming out of my charger on the seat next to me definitely triggers my male see-a-fire-put-it-out genes. I might be able to stop myself from stomping on it, after I'd tossed the whole chair in the yard.

6 minutes ago, Phi for All said:

I honestly don't think I'd be reasonable if this happened to me. 2-foot flame jets coming out of my charger on the seat next to me definitely triggers my male see-a-fire-put-it-out genes. I might be able to stop myself from stomping on it, after I'd tossed the whole chair in the yard.

Yes, I sympathise. I hope that in a similar situation, having now explored the issues, I might have sufficient presence of mind to react with some of these factors in mind. I did get hands-on training in how to, and how not to, put out oil fires, when I worked on the refinery at Shell. My late wife and I both worked for the company and at one stage they had a big push on domestic safety, as the home is where most accidents occur. As a result, I keep a fire blanket in my kitchen and have a water mist type extinguisher (which can be used on electrical fires) just outside my kitchen door. But I have never yet had to use them in anger.

I’m sure a lot of how one reacts is to do with the shock of the unexpected and whether one has some idea of what to do. At least now, thanks to @StringJunky ’s anecdote, we know the kind of effect that can be produced, so maybe we might stay a bit calmer if it happened to us!

1 hour ago, exchemist said:

My late wife and I both worked for the company and at one stage they had a big push on domestic safety, as the home is where most accidents occur.

That is a really great point. While I had a quite a fair bit of safety training (nominally, at least) and they are certainly somewhat transferable, I am pretty sure that I would react faster and more appropriate to, say, a fire in the lab vs a fire at home. Certainly something to think about, especially given all the llithium batteries we got here.

10 hours ago, CharonY said:

That is a really great point. While I had a quite a fair bit of safety training (nominally, at least) and they are certainly somewhat transferable, I am pretty sure that I would react faster and more appropriate to, say, a fire in the lab vs a fire at home. Certainly something to think about, especially given all the llithium batteries we got here.

It's chiefly "slips, trips and falls", apparently. My wife and I did do a sort of informal safety audit of the house (we all took it in turns to do these at the company, as a matter of safety policy) and the fire blanket and extinguisher were a couple of things that came out of that. I also got her to get rid of a lethal pair of wide-bottomed trousers she had, with turn-ups that could catch her high heels as she was coming down stairs. Falling down stairs is a classic: humdrum and absurd, but true. Ladders are another one. But yeah, with these Li-ion batteries, though the chance of fire is very low, if it does happen it's pretty serious and potentially could lose you your house if you have big ones indoors!

Another interesting finding from the company stats was that in spite of all the huge quantities of dangerous hydrocarbons and chemicals Shell handled on a daily basis, by far the commonest cause of lost time injuries on the company's time was.....road accidents. It was the sales guys who were most at risk, not refinery or oil rig operatives, as you might think. Hence the "engine on: mobile phone off" rule for driving. You would be automatically sacked for breaking that rule. Something of a culture shock in some countries, but that was partly the idea.

Edited May 21May 21 by exchemist

15 hours ago, Phi for All said:

2-foot flame jets coming out of my charger on the seat next to me definitely triggers my male see-a-fire-put-it-out genes

I guess you've never seen a pinhole in a pigtail connection leaking liquified Phosphine ( at 700 psi ) shooting like a blowtorch, 20 feet across the room.
Or a pump leaking hot, liquified Phosphorus all over the floor, burning at over 1500 degrees, and having to cover it with wet sand to smother the burning.
Or a gasholder bell, having reached its stops and blown out the water seal, surrounded by a ring of fire ( much lower pressure ) rising 50 feet into the night sky ( why does this crap always happen at night ? ).
And all the accompanying white smoke from the Phosphorus Pentoxide, which turns to Phosphoric acid when it contacts any unprotected mucous membranes, like throat and eyes.

Like all fire situations, keep calm, vent down any pressure, and isolate before attempting to fight the fire with all appropriate protection.
Ahhh, the joy of being on the Fire Brigade at 66 years of age ...

4 hours ago, MigL said:

I guess you've never seen a pinhole in a pigtail connection leaking liquified Phosphine ( at 700 psi ) shooting like a blowtorch, 20 feet across the room.

I am going out on a limb here and say that this applies to most of us here. (hopefully).

4 hours ago, MigL said:

Ahhh, the joy of being on the Fire Brigade at 66 years of age ...

Oh geez. And I am already getting annoyed being a designated fire warden. And all I have to do is yell at people.

9 hours ago, exchemist said:

Hence the "engine on: mobile phone off" rule for driving. You would be automatically sacked for breaking that rule. Something of a culture shock in some countries, but that was partly the idea.

What a splendid safety rule. If that bit of culture shock were applied in the USA generally, I have little doubt the accident rate would drop significantly. The thing that makes 700 psi phosphine jet like a blowtorch from my ears is when I see a pedestrian nearly mowed down because the driver is making a turn across the crosswalk and too busy yakking away on their cell to notice pedestrians.

BTW, did you say you worked for Shell? Do you remember those old hand calculators, where you could type in a certain number, flip the display upside down, and it would spell out ShELLOIL. (71077345, but only worked with those old displays with the numbers very crudely formed)

7 hours ago, MigL said:

I guess you've never seen a pinhole in a pigtail connection leaking liquified Phosphine ( at 700 psi ) shooting like a blowtorch, 20 feet across the room.

Not this week.

7 hours ago, MigL said:

Or a pump leaking hot, liquified Phosphorus all over the floor, burning at over 1500 degrees, and having to cover it with wet sand to smother the burning.

I would insist on dealing with this at the beach.

7 hours ago, MigL said:

Or a gasholder bell, having reached its stops and blown out the water seal, surrounded by a ring of fire ( much lower pressure ) rising 50 feet into the night sky ( why does this crap always happen at night ? ).

Not as memorable during the day.

7 hours ago, MigL said:

And all the accompanying white smoke from the Phosphorus Pentoxide, which turns to Phosphoric acid when it contacts any unprotected mucous membranes, like throat and eyes.

Closest I've come lately is a bit of sulphur hexaflouride in my right eye.

7 hours ago, MigL said:

Like all fire situations, keep calm, vent down any pressure, and isolate before attempting to fight the fire with all appropriate protection.

Venting by throwing the chair and charger out into the yard, thus isolating it. Other than the calm part, I think I nailed it.

2 hours ago, TheVat said:

What a splendid safety rule. If that bit of culture shock were applied in the USA generally, I have little doubt the accident rate would drop significantly. The thing that makes 700 psi phosphine jet like a blowtorch from my ears is when I see a pedestrian nearly mowed down because the driver is making a turn across the crosswalk and too busy yakking away on their cell to notice pedestrians.

BTW, did you say you worked for Shell? Do you remember those old hand calculators, where you could type in a certain number, flip the display upside down, and it would spell out ShELLOIL. (71077345, but only worked with those old displays with the numbers very crudely formed)

Hoho, In the UK too! The police keep running campaigns - you get fined and get points on your licence that can accumulate enough to ban you from driving - but it is hard to stamp out.

Yes I worked for Shell for 33 years. Now that I'm retired my rule is never to answer or look at texts while the engine is on, but I confess I don't any longer actually turn the phone off. So I do hear the beep or the ringtone and if I'm waiting for a message or a call I will at some point pull over, turn the engine off and look at it. But then, being retired, I don't get anything like the volume of calls and messages that someone working would get.

I remember being shown the digital display trick but it meant less to us in Europe as "Shell Oil" was the name of the US subsidiary. We were in Shell UK Ltd or Shell France SA or whatever, or else, as I later was, in Shell International Petroleum Company (known as SIPC).

I remember a number of our guys in Eastern Europe who got sacked for using their phones in the car - they couldn't believe the company was serious. But it was.

In fact, now I'm getting old I find I need to concentrate more and more on the road when driving. When I was younger I liked to play classical music. Now however I find I tend to pay too much attention to the music and not enough to the road conditions. So I drive in silence.

Edited May 21May 21 by exchemist

Here in my home town in UK, all 188 residents living in a city centre tower block had to be moved to emergency accomodation following a large fire on Tuesday.

https://www.bbc.co.uk/news/articles/cpd440yee07o

Group manager for Avon Fire and Rescue Service, Paul Smith, has now confirmed the fire was caused by the charging of an e-scooter and that it has been recorded as an "accidental ignition".

Two years ago, London Fire Brigade released dramatic video footage of a similar incident  where the lithium battery of an  E-scooter exploded while left on charge in a kitchen.

On 5/20/2025 at 3:51 PM, StringJunky said:

Appreciate your thoughts, and my lesson I got from it was "people first" and get out of the way asap, rather than trying to deal with it when the thermal runaway is in full flow. The first actual concern was the furniture, which on reflection was the wrong priority.

The lesson that comes to mind is a piece of safety advice my father was once given on handling radioactive isotopes at Harwell - "Presence of mind, and absence of body ! "

Edited May 21May 21 by toucana
Corrected 'Harwell'