Crushed Positive end of NCR18650GA battery; cause of heat?

[Modernflame]

Well, yes, but 18650s are in every laptop. They don't normally short-out. I can certainly see why you'd want to store the ones you're not using, but why recycle ones you don't use? Stick them in the refrigerator, and maybe you'll need them in a year or two.

Actually, this battery went bad the way it is supposed to: no explosion, no fire. Good, name-brand cells are torture-tested and have to pass like this. It's still scary, but it didn't cause any danger other than heat.

Ultrafire and Trustfire batteries are the ones I'd worry about. They're dangerous, except for the fact they have so little power in them they probably aren't a huge risk.

I'd like to hear what caused this Panasonic GA battery to go bad. It's definitely concerning, but I'm not about to stop using my cells because of it.

I won't stop using them. And yes, I eyed my laptop suspiciously for the first couple of months. Cell phones use the same battery tech as well. I'm not paranoid (at least I don't think so). I just feel more comfortable with a smaller number of cells in active use. Right now, I've got two 18650's charged to about 4.1v, one protected and one unprotected. This just means I'll have a lot of empty lights until I'm ready to use them. I also have a couple of lights running primaries.

A thermal runaway event with an 18650 is extremely unlikely, but I've had one in my living room before. Projectile flames and poison gas. Yep. I don't believe that lighting will strike me twice, but I've become abundantly cautious.

 

[geokite]

Thanks to all for the replies. I order some Samsung 30Q cells from Illum in the bay area. I guess just to be safe? Safer? ZL gave me a RMA, it is in-route back to them. I'm starting to think the compression had nothing to do with the thermal event.

 

[WalkIntoTheLight]

I'm really only concerned when charging.

When I get new batteries, I charge them up to full, and then let them sit for a couple of weeks before using. After the initial (normal) voltage drop, I monitor them to make sure there is no more voltage drop. That could indicate there is a small internal short.

If they pass my test, I'll use them.

I do the same test on laptop pulls, though I'm a bit more forgiving on the initial voltage drop.

I know we can't go back in time, but I wonder if this GA battery would have passed that simple test?

Anyway, this has me thinking I should probably do that test to my cells that I regularly use, as well. Perhaps, every 6 months?

 

[Modernflame]

I'm really only concerned when charging.

When I get new batteries, I charge them up to full, and then let them sit for a couple of weeks before using. After the initial (normal) voltage drop, I monitor them to make sure there is no more voltage drop. That could indicate there is a small internal short.

If they pass my test, I'll use them.

I do the same test on laptop pulls, though I'm a bit more forgiving on the initial voltage drop.

I know we can't go back in time, but I wonder if this GA battery would have passed that simple test?

Anyway, this has me thinking I should probably do that test to my cells that I regularly use, as well. Perhaps, every 6 months?

Hadn't thought of that before. Based on the declining voltage of the OP's battery, that could be an insightful test. Personally, I don't charge my cells to 4.2, but I suppose it would be worthwhile to put a new cell through its paces.

My testing process usually involves hawkish oversight while charging, a fire extinguisher near by, and a charger plugged into a socket that I can switch off at the wall. I will use the new cell, but not in a pocket carried edc light until it's been through several charge/discharge cycles. Going forward, I think I will incorporate your test.