Li-ion Battery Safety

I have a bunch of 5 year old Li-ion batteries in sizes 18650 down to 10440 (protected & unprotected) that are either in flashlights or stored in a drawer. Some haven't been charged for a long time. Going away for a week and am curious about leaving these alone. Is there any danger of these causing a problem while we're gone?

It can be hard to get clear answers on this.

torpeau said:

I have a bunch of 5 year old Li-ion batteries in sizes 18650 down to 10440 (protected & unprotected) that are either in flashlights or stored in a drawer. Some haven't been charged for a long time. Going away for a week and am curious about leaving these alone. Is there any danger of these causing a problem while we're gone?

It can be hard to get clear answers on this.

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I have always been told that you shouldn't take chances with Li-Ion batteries and should always be closely monitored

Hello Torpeau,

As long as they are properly stored there shouldn't be a problem. Make sure they have no chance of shorting and don't store them in a charger.

If you are still concerned, throw everything in the refrigerator. That way if something unexpected happens (like your house burns down... ) they will be contained.

Tom

The protected ones should be theoretically fine... but the unprotected could be a problem- by could, I mean likely. Your best bet with any batteries, if you aren't using them in a device then pull them out of the devices and store them such that they will not make contacts that will cause a short. 9V are the mostly likely to get shorted easily, but there is potential with all batteries. As SilverFox says, if you are worried then just stick them in your fridge, safe or other thick walled container so if something happens then they won't be an issue... or if they are an issue, they will be contained.

I've seen a 10440 get shorted (someone cut the protection circuit off, which leaves wires that will short the battery). Just some liquid sprayed out, staining a cardboard box. It looked and sounded impressive and the smell was unpleasant... but it seemed harmless. I imagine a larger battery (18650) might be more troublesome should it be shorted.

Just so I understand, were saying that leaving a li-ion battery in a flashlight is a hazard? Or even stored in a drawer? I mean, as long as they aren't touching anything shouldn't they be fine?

It depends on the flashlight. If it has a quality mechanical switch that physically disconnects them from the circuit it should be fine.

Kicking around in a drawer is fine if there is no loose metal to cause a short.

Here is the thing, they are batteries, the put out power. Alone they are fine. If you toss them in a drawer full of junk, and they get jostled around in such a way that they touch something metal, that touches something else metal, that touches the other end of the battery and shorts it, then yeah you have a problem.

But if you put them all nice in a storage box, or positioned carefully, basically common sense stuff to avoid the chance of a short, they could sit there a very very long time without incident.

Chances are if they have been somewhere for a long time without a problem, they will continue to not have a problem unless you change something.

Often the true hazard of batteries comes from their continued use after abuse.

In lights: I store mine with the tail cap locked out (not making contact).
Outside of lights: I store mine in cases. I have specific cell holders & a small pelican case too.

Never had a issue.

I mitigated all these concerns with LiFePO4​.

snakyjake said:

I mitigated all these concerns with LiFePO4​.

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It's not a replacement for ICR or IMR.

snakyjake said:

I mitigated all these concerns with LiFePO4​.

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In fact, LiFePO4 are capable of delivering extremely high current. So an electrical short is just as bad, or could even be worse. The faster it can discharge, the more damage it can do, generally speaking.

As stated, store them properly, and you'll be fine. There is no reason to be concerned about them suddenly shorting out while you are away. The same precautions apply whether you are monitoring the cells, or not.

I'm sure there are pawn shops, homes, warehouses, etc. with 15+ year old laptops and old batteries sitting around. Doesn't seem to be a problem, unless it's just not getting attention in the news. A few stories here and there (Tesla, air plane) but I think those are differnet cirucumstances than what we're talking about here.

If they were ticking timebombs waiting to explode and burn your house down while you vacation, I think there would be a much more evident warning on them, or not even sold to the public in the first place.

My attention is focused on charging and in use.

I concur with mark6. I wonder what the odds are? I am not a statistician partly due to not having a Holiday Inn Express near by. But if there are only a dozen scary samples of explosions on a google search out of a wild guess of 10,000,000 batteries sold, I would say the odds are pretty slim you are going to run into problems.

The ones with protection should be fine, unless the house burns down around them or the protection fails.
Any unprotected batteries are far more susceptible to shorting (one of the things the protection prevents), but also more likely to over-discharge when left in a device. When a battery sits unused long enough, it can be hard to recharge them... and that happens sooner while in a device since it drains it a little faster. I don't know how long it takes to reach that state, but if you haven't used a particular battery in several months then it might be a good idea to test that it still holds a charge anyway - whether protected or unprotected.
Either way, they should only be a problem if they have more than a little charge and get shorted... or get tossed in a fire.
I've seen a Ni-MH get revived from being over-discharged... but it was dangerous as it was put in a charger that was too strong for Ni-MH, so we had to pull the battery once it showed that it had advanced in charging it.

Ok sounds like its more of a use some common sense. I figured as much. When I get my li ion batteries I will have cases for them. Being smart about your stuff should pretty much eliminate accidental hazards. Of course you can't rule out malfunctions completely, so you would want to just be aware of the possible hazards, and probably store them away from other such flammables and what not.

pipes said:

Ok sounds like its more of a use some common sense. I figured as much. When I get my li ion batteries I will have cases for them. Being smart about your stuff should pretty much eliminate accidental hazards. Of course you can't rule out malfunctions completely, so you would want to just be aware of the possible hazards, and probably store them away from other such flammables and what not.

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Yes common sense goes a long way. Lots of Li-Ion talk and youtube videos blowing safety way out of porpotion in the echo chamber. Look at my garage, which I think it pretty typical: all within a few feet you have cans of spray paint, stain, ether, starting fluid, 2 gal tank of gasoline, lawn mower (filled with gasoline), citronella oil, few quarts of motor oil, etc. I also have a Black and Decker Li-Ion Dust Buster near by. Nice item by the way. If those batteries blew up, I'd be in for some trouble. But I have absolutely NO worries about it. Oh yeah a cordless drill pack occasionally on the charger as well.