Plastic ring fel outl of positive end on flat-topped 18650. Does it matter? Unsafe?

[Naguz]

So recently I bought some Samsung ICR18650-30B 18650's. As you can see from the pictures, it has a (thin) white plastic ring around the positive end. Now, unfortunately, I slid this into a cheapo 18650 storage box with leads for charging, and the positive contact in the box stuck into the white plastic ring without me noticing. When I pulled the battery out, the ring got ripped out. There is a miniscule tear in the mold line in the protective film/casing on the battery which doesn't extend beyond the top edge, and which can be easily be repaired by tape. But does this plastic ring perform any function making it unsafe for use? As far as I can see, it does not perform ANY function escept making the batt look nice. But hey, this is Lithium. So I ask you guys to be sure. Any thoughts?

I'll see if I can take any pictures of it tomorrow if that would be needed to say anything about the function of this little plastic bit.

 

[bjt3833]

Depends on how badly the battery was damaged. If just the ring came off, I wouldn't really think much of it. From the best I can tell the rings might help hold the positive terminal on and protect it slightly if it even does that much. It's my understanding that the positive contacts are welded onto the batteries usually tho so it should stay on fine. But with the price fasttech has the batteries for, I might would just replace it anyway.

Im sure you know this already but those are unprotected batteries so I'd prolly err on the side of caution with possible shorts caused by damaged wrappers. I did just buy some battery shrink wrap to solve the problem of damaged wrappers on my batteries just in case.

 

[KiwiMark]

The middle raised metal part is the +Ve terminal but the metal under that plastic ring is the -ve terminal (-ve goes all the way from the bottom right up the sides and around the edge of the top) so that plastic ring performs a safety function in preventing a short circuit. As long as you ensure that nothing metal can bridge the gap from top middle to top edge causing a short circuit then you should be fine.

 

[Naguz]

Im sure you know this already but those are unprotected batteries so I'd prolly err on the side of caution with possible shorts caused by damaged wrappers. I did just buy some battery shrink wrap to solve the problem of damaged wrappers on my batteries just in case.

Well, that's what I thought also. They're going into a 4x18650 USB travel power pack thingy which isn't for myself. I'll just giver her one with my batteries pretty new 18650s and buy some new ones for myself. Even if I'm pretty positive it wont be possible for anything in the box they'll be used with to cause a short. (Pretty flat and smoothly rounded positive contact in the box). Thanks to both of you.

BTW, is there a "safety sheet" or similar available for rechargeable Li-ions? Don't overcharge, dont short curcuit, fumes and chemicals released if venting etc? I thought I saw something like that in the safety forum ones, but can't find it now. Would be nice to give with it just in case.

 

[bjt3833]

There's an abundance of information on this forum but I think the sticky at the top of this sub forum has that link in it.
Also battery university is frequently referenced.