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What chemicals inside hear aid batteries makes them explode?

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gary350

Well-Known Member
There must be an explosive chemical in batteries that make them explode what is it? This is an electronic device I figure someone will know.

I saved about 75 dead hearing aid batteries & then threw them in a fire I built in the back yard. It took about 6 seconds for them to start started going, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom, Boom. Most of them exploded within about 8 seconds. It was as much fun as shooting off a whole package of firecrackers. I never found the remaines of any of those batteries. I though there would be at least 1 metal battery body but, nope.
 
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Externet

Well-Known Member
Because the cell chemicals create expanding gases with the heat and the seal in the cells is very good so they do not vent but blow up at rupture ?
 

JimB

Super Moderator
Most Helpful Member
A bit like this I guess:


JimB
 

gary350

Well-Known Member
Because the cell chemicals create expanding gases with the heat and the seal in the cells is very good so they do not vent but blow up at rupture ?
WHAT chemical produces expanding gas? When water reached 212 degree F = 100 degree C its volume increases 1800 times when it turns to steam. At 170 degree C mercury volume increases, I forgot the exact number but its about 3000 times. Many things turn to expanding gas at a certain temperture. Get more specific what makes a hearing aid battery explode.
 

audioguru

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My hearing aid batteries are zinc-air so they have vents to let the air in for the chemical reaction to work. When they get wet in rain then they stop working until I dry their vents. I will not put them in a fire to see if they explode.

I finished playing with explosives when I was a kid and I am lucky that I still have all my fingers.
 

gophert

Well-Known Member
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WHAT chemical produces expanding gas? When water reached 212 degree F = 100 degree C its volume increases 1800 times when it turns to steam. At 170 degree C mercury volume increases, I forgot the exact number but its about 3000 times. Many things turn to expanding gas at a certain temperture. Get more specific what makes a hearing aid battery explode.
So curious but so lazy. How do you expect an answer if you don't even bother to tell us what chemistry is used for the batteries (Zinc-air, silver oxide, ???).

Also, you need to review your general chemistry notes. A confined sample of water does not expand 1800 times when it is heated to 100°C. It stays nice and content as a liquid. Since no fire burns at 100°C, you can first use the thermal expansion of water and the available "head space" to determine the pressure inside the battery (assuming it is not zinc air).

You can also look up "head space", "max fill line" and pressure relief devices to better understand how pressure builds up around room temperature and then take the time to do the calculations for temps in a red-, orange- or yellow-hot fire.

Final note, there are no "explosive" chemical ingredients in a battery used in your home unless you include vapor cloud explosions -which is not possible with a handful of hearing aid batteries.

An explosion is a specific type of reaction where explosive includes both the oxidant and the fuel to make an expthermic reaction that generates gaseous products. It does not rely on atmospheric oxygen. The you just cant get a fast enough exchange of atmospheric oxygen with the fuel to get a blast front that will make a pop. That means, the pop you heard was the battery case rupturing because of expanding liquids or gas are venting a super-heated pressurized vessel. In all likelihood, water. See steam engine explosion for an example.
 

gary350

Well-Known Member
So curious but so lazy. How do you expect an answer if you don't even bother to tell us what chemistry is used for the batteries (Zinc-air, silver oxide, ???).

Also, you need to review your general chemistry notes. A confined sample of water does not expand 1800 times when it is heated to 100°C. It stays nice and content as a liquid. Since no fire burns at 100°C, you can first use the thermal expansion of water and the available "head space" to determine the pressure inside the battery (assuming it is not zinc air).

You can also look up "head space", "max fill line" and pressure relief devices to better understand how pressure builds up around room temperature and then take the time to do the calculations for temps in a red-, orange- or yellow-hot fire.

Final note, there are no "explosive" chemical ingredients in a battery used in your home unless you include vapor cloud explosions -which is not possible with a handful of hearing aid batteries.

An explosion is a specific type of reaction where explosive includes both the oxidant and the fuel to make an expthermic reaction that generates gaseous products. It does not rely on atmospheric oxygen. The you just cant get a fast enough exchange of atmospheric oxygen with the fuel to get a blast front that will make a pop. That means, the pop you heard was the battery case rupturing because of expanding liquids or gas are venting a super-heated pressurized vessel. In all likelihood, water. See steam engine explosion for an example.
Water boils at 212 degrees F that = 100 degree C. When water turns to steam its volume increases 1800 times that is what makes a steam engine go. According to the definition of the law oxidizer and fuel will make an explosive but there is none of that in an Atom bomb. You need to learn chemistry, 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. By definition of the law water is not an explosive. There are several chemicals in everyone's home to make explosive, example, gasoline & air. Propane & air or natural gas & air did you ever see a gas leak explode on TV News. Mix laundry ammonia with Iodine you get Nitrogen Triiodide a very powerful explosive. Mix ammonium nitrate fertilizer with laundry bleach you get an invisible gas that explodes when it comes in contact with sunlight. There are many things in your house that will make explosives I could tell you 15 more. I have asked this question on the wrong forum it needs to be on the physics forum.
 

Beau Schwabe

Active Member
There are plenty of smart people in this forum that know a thing or two about physics completely capable of entertaining an answer to your questions, but please be careful about giving suggestions that could harm or kill someone. There are also plenty of naive people also in this forum that might just go and try to mix a few things together. in other words, think before you speak please,

Keeping things relatively simple here is a question ....
Do you get more useful power from the expansion of water into a gas or when it rapidly condenses from steam back into a liquid?
 
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gophert

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Water boils at 212 degrees F that = 100 degree C

1)
True, but only at 760 mmHg atmospheric pressure and can freely expand.

At lower atmospheric pressure, boiling point decreases.
Likewise, if you put that water in a sealed container, you can keep adding heat and build up pressure - all while the water remains in the liquid state until you either reach the triple-point or the vessel ruptures (or both).

2)
What hearing aid batteries are made of materials that can be used as the fuel for a nuclear bomb?

3)
Still not willing to share the type of battery you used?
 

dknguyen

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Apparently there were bad zinc-air hearing aid batteries a while back that would explode. The article I found said that the zinc electrode reacted with the electrolyte to form hydrogen.
 

gophert

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Apparently there were bad zinc-air hearing aid batteries a while back that would explode. The article I found said that the zinc electrode reacted with the electrolyte to form hydrogen.
The OP said he threw 75 old batteries into fire. Has nothing to do with poorly manufactured batteries.
 

dknguyen

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The OP said he threw 75 old batteries into fire. Has nothing to do with poorly manufactured batteries.
Yeah, but wouldn't you expect properly manufactured batteries to behave like poorly manufactured batteries in a fire?
 

gophert

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Yeah, but wouldn't you expect properly manufactured batteries to behave like poorly manufactured batteries in a fire?
I'd expect to have some information about the battery chemistry before I would bother hypothesizing about the mechanism. But, to answer your question, I would expect any reaction that could happen to happen and any gaseous products and residual water to overpressurize the container and pop.
 

dknguyen

Well-Known Member
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I'd expect to have some information about the battery chemistry before I would bother hypothesizing about the mechanism. But, to answer your question, I would expect any reaction that could happen to happen and any gaseous products and residual water to overpressurize the container and pop.
It is weird that the OP has not answered requests for battery chemistry and just keeps going on about nothing, even in the initial post. I didn't take this as a serious post but then people started responding seriously.
 

Reloadron

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Most Helpful Member
When a battery explodes in a fire does it really matter why the battery exploded? Now I sort of figure it like this. When a battery explodes there will be the pesky remains of the battery traveling at a pretty high velocity. How fast? Well I really don't know but I know, to quote a Christmas classic. "you'll shoot your eye out with that". A well placed piece or let's say fragment could not only take out an eye but likely penetrate light clothing and manage its way between a few ribs and wreak havoc with a heart. Now I have heard and read a battery can explode and be it from pressure due to a chemical reaction or simply a chemical reaction really matters not as I figure it is a good idea not to do stupid things and then question results. Sort of like urinating into a wall outlet just to see if it will result in a shocking experience.

Ron
 

gary350

Well-Known Member
OK I asked the wrong question. I should have asked, what chemical inside the battery makes it explode?
 
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Reloadron

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OK I asked the wrong question. I should have asked, what chemical inside the battery makes it explode?
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
 

Les Jones

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Most Helpful Member
If it is the type of cell that has to have a piece of sticky tape removed before use then it will be zinc air. Do you have to do this ? If you won't tell us what chemistry the cell uses then at least provide the type number of the cell and we can find out from that. By the way it is not reccomended to dispose if any type of cell (Or battery) by buring it.

Les.
 

Wirth's Law

Member
Many battery types are either hermetically or mechanically sealed; very often using steel. In a fire, this essentially creates a pressure vessel of trapped vapors and hot catalyzing metals. For zinc-air batteries--which are semi-permeable--you're still burning a large, spent anode of zinc oxides, highly-caustic potassium hydroxide, and possibly metal peroxides. Also, until somewhat recently, virtually all coin cells contained small amounts of mercury; an extremely toxic material. (see: Environmental Protection Agency (EPA): "Mercury in Batteries") To dispose: many battery retail stores and hardware stores will accept your old batteries for free.
 
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