Will an over-discharge li-ion battery explode?

Will an over-dischage li-ion battery explode if left untouch till it discharged or completly drain? Sorry if this was answer already, but I've been searching cpf and only came up with one related tread back from 2005 "http://www.candlepowerforums.com/vb/showthread.php?81168-What-happens-when-a-Li-ion-is-over-discharged" which didn't really answered my question.

Reason is because I lost a flashlight with an 18650 battery somewhere in my house last year, and not sure if that will be a problem.

It'll just drain to zero volts and then no longer accept a charge. 18650s can last a very long time just sitting on their own though, so keep searching.

Edit: I should be more specific - it'll drain to zero volts and could then explode if you attempt to recharge it. If you find the battery and it tests over 3 volts (entirely possible in a one-year time frame,) it's still perfectly good and you can charge/use it normally. If it's under ~2.7 volts, toss it.

Thank you for the reply. =)

I don't have interest in recovering the battery if I find it because I'll probably safety dispose of it. It was a cheap trustfire battery. I own eagletac batteries now.

So as long as no one tries to charge it then I'm good right? It would suck if it explode and catches on fire. Then that would be kinda bad.

Still searching but I just can not find it. Just hoping no finds it or stole it from me and hurt themselves if that were the case.

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This a good question that I also haven't found a definitive answer to, but logic tells me that if it isn't holding any charge, it doesn't hold any energy and therefore can't explode/vent with flame unless one tries to charge it but I'm certainly not sure about this logic. I hope someone who knows will chime in.

Hello Duckied,

Welcome to CPF.

First of all, Li-Ion cells don't explode... They can rapidly vent and that is sometimes accompanied by flame.

Mechanical damage can cause the cell to short which can lead to rapid venting. So, if you have an earthquake and stuff falls off the shelves you may be at further risk if the light and the cell inside become damaged.

Heat can also cause problems. If you house catches on fire, the fire may receive an additional boost from the cell in the light as it rapidly vents.

Aside from these extremes there should be no problem. As others have mentioned the problem comes during charging if the voltage has dropped too low.

Tom

Thank you Tom, that does make me feel better. I'd figured I'm just being overly paranoid.

But as for the exploding part. If a cell vent and flames up in a air tight container would it not explode due to the pressure not being release?

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Hello Duckied,

Now that would depend upon the integrity of the air tight container...

We have had a few incidents reported here. In some cases part of the flashlight flew across the room and dented the wall. In other cases the light just fell apart. Considering the number of flashlights, laptops, and cell phones in use the number of incidents is very small.

While it is important to follow basic common sense and safety the use of Li-Ion cells is nothing to be paranoid about. If you want to be paranoid about something you probably have a better chance of a car crossing the yellow line and hitting you than experiencing an incident with a flashlight.

Tom

Cool thank you very much for your help silverfox!

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Remember: the extreme form of the reaction which leads to venting with flame is "spontaneous rapid disassembly." They never explode, just as they never burn.
They do, however, set other things on fire. Particularly airplanes.


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JanCPF said:

This a good question that I also haven't found a definitive answer to, but logic tells me that if it isn't holding any charge, it doesn't hold any energy and therefore can't explode/vent with flame unless one tries to charge it but I'm certainly not sure about this logic. I hope someone who knows will chime in.

Click to expand...

Keep in mind that it's not the 'charge energy' that makes a lithium ion battery vent with flames. Rather, it's a reaction between the flammable electrolyte and the (easily) liberated oxygen atoms in cobalt oxide. This can happen regardless of the state of charge of the battery.

I had 6 Sanyo 18650 red label, that I fully charged and totally forgot for about 4 or 5 years .
When I checked on them, they had bubbles all over the envelope, and the voltmeter indicated a voltage of about 1v-2v.

> a reaction between the flammable electrolyte and the (easily) liberated oxygen atoms in cobalt oxide.
> This can happen regardless of the state of charge of the battery.

Yep. Look up 'crystal growth'
https://www.google.com/search?q=lithium+ion+cell+crystal+membrane

crystals slowly grow inside an old/damaged cell, and eventually put a hole in the membrane separating the chemicals.

There's no way to tell how any individual cell is made, li-ion cells have been made a lot of ways, not well documented nor tested.

Quick question, I have a half dozen old cell phones (all 2-7 years old) that are sitting in a box in a closet in my house. Twice I've had to use one as a replacement phone when my main phone has broken.

My question is: shouldn't the cells have exploded by now?!

Knowing what I know now, I cringe to think I put a "dead" Li-Ion pack in the closet and stored it for YEARS. Why haven't they over-discharged and exploded?

Hello ThirstyTurtle,

The answer to your first question is no.

Your second question is in two parts. The answer to the first part is that you most likely shut the phone off before storing it. The second part has been answered earlier in this thread. To summarize you can discharge a Li-Ion cell to 0 volts without incident. Charging it back up could be a different story.

Tom

I am new to the forum.

Once I had a Chinese guy offer me 10,000 LG 18650 cells for $1.00 each. When I asked him why, he told me that there were a few cells in the lot that would suffer "Rapid Disassembly" and there was no way to tell which ones until it happened.

I politely declined his offer. But, I bet he sold them to somebody.

I don't know why LG didn't destroy the cells.

Pete Steinmetz

P Steinmetz said:

I am new to the forum.

Once I had a Chinese guy offer me 10,000 LG 18650 cells for $1.00 each. When I asked him why, he told me that there were a few cells in the lot that would suffer "Rapid Disassembly" and there was no way to tell which ones until it happened.

I politely declined his offer. But, I bet he sold them to somebody.

I don't know why LG didn't destroy the cells.

Pete Steinmetz

Click to expand...

That is why i never buy batteries on the fleabay.The Chinese never throw anything away.