What chemicals inside hear aid batteries makes them explode?

I recently found out that lithium coin cells (cr2032 etc.) are responsible for starting many fires. Especially in towers. Seems they get crushed by the compactor at the bottom on the trash shute and start a fire.

Mike.

Reloadron said:

No, you should have included the battery chemistry. The question as to why they exploded can't really be addressed without knowing the battery chemistry. Lithium batteries explode for some reasons while alkaline batteries explode for another reason and the list goes on.

Ron

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So name them all???

gary350 said:

So name them all???

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If you can't be bothered, why should anyone else?

Mike.

gary350 said:

So name them all???

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Most people would start with the one, two or three on the label. But, since you knew that already, you also know something else. Right?

gary350 said:

So name them all???

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I don't recall me being the one asking why batteries explode in fires? You were given plenty of adequate answers and as of yet have not mentioned the chemical composition of your batteries in question? How about rather than me or anyone else naming them all you try Google which can become your new best friend?

On the bright side all this coin cell stuff reminded me to change the 327 battery in my electronic caliper.

Ron

From the original description, I'm guessing they were zinc-air batteries, or zinc-silver oxide. Both have good energy density and shelf life for this application. If the batteries were very old (maybe from the late 90's or earlier), they could be mercuric oxide batteries. These are bad news and were phased out for toxicological/environmental reasons.

i would say that the most likely reason for batteries exploding in a fire is pressure buildup in a confined space, and rupturing the container. i had the same experience as a teenager. one job i had occasionally required me to dump trash in an incinerator, and one day, there were a lot of AA batteries in the trash.

knowing the specific chemistry of a battery isn't really going to be helpful in identifying why the battery exploded in the fire if the battery case is hermetically sealed, because such an explosion will happen regardless of battery chemistry. it's just a matter of thermal decomposition or reaching the boiling point of something inside the battery generating enough pressure to make the container fail. i think that even carbon-zinc batteries these days are also sealed inside a durable container, so the boiling of water inside even one of these will cause an explosion.

gary350 said:

I can blow a hole the size of a basketball through a 3/4" thick sheet of plywood with 1 tablespoon of water, see if you can figure out how that is done. LOL.

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I would like to know how you do this with nothing but 1 tablespoon of water.

I think there is some confusion or pedantic differentiation between a detonation type explosion and pressure release explosion.

A pressure vessel burst causes an explosive event and shock wave in just the same way (in outward effect and sound) as a chemical explosive detonation.

eg.

The battery casings are in effect pressure vessels.
Causing any constituent of the cell to vaporise and boil will cause a significant pressure increase and combined with heat softening the insulator/seal, an eventual "bang".
It does not need any chemical reaction more complex than that.

As others have said, there are many different possible substances depending on the exact battery chemistry [silver, alkaline, merci=urey, etc. etc.] and that has not been stated - so any attempt to specify what is being vapourised is total guesswork.