Spring contacts + and - of a AW IMR26500 Battery, then CATCHES ON FIRE

[SmurfTacular]

EDIT: apparently these are not protected. For some reason I got the impression these where protected... Why the hell do these cost $15 a piece then?

I've ordered from AW before with no problems. But today was different. Today a 26500 caught on fire on my desk.



I bought two 26500 cells directly from AW to use for a 2D P7 Maglite. I put PVC in the Maglite to accommodate the room. I also soldered a spring to the negative terminal of the switch to accomidate the empty space. After these slight modifications where done, I put the two 26500 cells in correct polarity in the Maglite. After screwing the tailcap on, I turned the switch, and I measured 8.2 volts out the front. So I put down my multimeter, and I look at the Maglite and smoke was seeping from the hole of the switch. I immediately unscrewed the tailcap and pulled the batteries out. On of them immediately caught on fire once it made contact with oxygen. I threw a towel over it, smothered the flame out, grabbed it, and ran outside and tossed it onto the ground.

Here are some pictures:

The spring was not bent like this before I put the cells in. The spring was completely straight.

What have caused this battery to spontaneously combust like this?







.

 

[hoongern]

Re: AW "Protected" Battery CATCHES ON FIRE

Your pictures aren't loading.. you may want to try uploading them to an image hosting website.

Also, do you mean the AW IMR26500 cells? These aren't protected cells - and if they do get into a short circuit for whatever reason, they will release HUGE currents and could result in not so desirable results.

However, I won't conclude anything. Waiting for those pics =) Can you show the spring you soldered on as well, if it's still possible?

Was the other cell hot as well?

Glad that you're safe though!

 

[Chauncey Gardner]

Re: AW "Protected" Battery CATCHES ON FIRE

I can't see any pics coming up Smuf, but you're cracking me up.

These aren't any of the batch you used the belt sander on are they?

No guesses beyond that.

edit:
I imagine you as a budding young McGuyver, lol.

 

[Mr Happy]

Re: AW "Protected" Battery CATCHES ON FIRE

I don't see the pictures?

 

[jasonck08]

Re: AW "Protected" Battery CATCHES ON FIRE

Links to the pictures are broken or not showing up...

 

[8Fishes]

Re: AW "Protected" Battery CATCHES ON FIRE

Man.. I'd love to see pictures but since none of us can log into your google mail account, I don't think it was a good idea to link it from there

 

[flashfiend]

Re: AW "Protected" Battery CATCHES ON FIRE

Invisible fire or a short in the system? I can't see the pictures as well.

 

[Chauncey Gardner]

Re: AW "Protected" Battery CATCHES ON FIRE

I hope he's ok

 

[Hack On Wheels]

Re: AW "Protected" Battery CATCHES ON FIRE

What was the spring like that you soldered onto the switch? My first thought is that it may have poked through the shrink wrap beside the button top and shorted the cell.

It definitely sounds like a shorted cell. However, I'm not sure I understand your voltage measurement... how/where did you measure it?

 

[45/70]

Re: AW "Protected" Battery CATCHES ON FIRE

This should most likely be in the "Smoke and Fire" thread.

Anyway, pictures that you can actually see would be nice. I don't normally speculate with so little information, but 99% of my attention is on the "I also soldered a spring to the negative terminal of the switch to accomidate the empty space" part. A wild guess? The spring shorted out and resulted in a massive current dump inside the light. LiCo cells, or more likely these were IMR's, could dump a lot of heat when shorted. And if they were IMR cells, there is no protection circuit on them.

EDIT: Ya beat me Hack!

Dave

 

[kramer5150]

Re: AW "Protected" Battery CATCHES ON FIRE

Do post back the pics.

This spring you soldered on to take up the extra space sounds very suspicious. I have seen it before where long-ish springs would collapse or "fold" over, get crushed or mangled the wrong way. it doesn't take much to short +B to -B at the top of the cell. The two HOT points are very close together.

I am merely speculating though... need pics

 

[SmurfTacular]

Re: AW "Protected" Battery CATCHES ON FIRE

I can't see any pics coming up Smuf, but you're cracking me up.

These aren't any of the batch you used the belt sander on are they?

No guesses beyond that.

edit:
I imagine you as a budding young McGuyver, lol.

I was waiting for that. I guess I'm a magnet for destroying batteries.

Pics are up now

I hope he's ok

Yeah I'm fine. I just need a change of boxers because I #%&@ my pants when I saw the flames.

What was the spring like that you soldered onto the switch? My first thought is that it may have poked through the shrink wrap beside the button top and shorted the cell.

It definitely sounds like a shorted cell. However, I'm not sure I understand your voltage measurement... how/where did you measure it?

I removed the bulb and measured the + and - on the bulb holder thing. (excuse my lack of Maglite vocab)

 

[JaguarDave-in-Oz]

Re: AW "Protected" Battery CATCHES ON FIRE

Wow, long spring.

I reckon you'd be on a hiding to nothing that a spring as long and narrow as that one is sooner or later going to short out by either slipping off the battery centre, spiking through the insulation or bowing out or some combination of the above as looks to have happened here just looking at the apparently overheated spring end.

 

[cernobila]

Re: AW "Protected" Battery CATCHES ON FIRE

Looks like an IMR cell, these are not protected hence the problem as mentioned by others already.

 

[flashfiend]

Re: AW "Protected" Battery CATCHES ON FIRE

I hope we're not blaming this on the battery. Granted a protected one 'might' have averted the flame up.

 

[VidPro]

Re: AW "Protected" Battery CATCHES ON FIRE *pics updated*

finnally the pictures.
looks like the Spring hook hole syndrome, a common possibility.
spring gets under insulation around nipple making direct short to the batterys metal can edge where it is slightly exposed under the insulations there.

could be why most springs on lights are tapered, have the end twisted down , and generally have a specific design about them.
why various battery holder things (including adapters) have a way to prevent shorting even if the worst things happen to them.

what the hey, you just learned one more thing , adjust thinking of the possibilities and DO IT again.

many devices go way overboard in this area, and some stuff just completly ignores it till the spring smushes, twists, heats, and bends. now you get to go way overboard making sure that can never happen again in anything you do ever again in your whole life

.\/ spring end up right there
-____-+-___-

 

[Niconical]

Re: AW "Protected" Battery CATCHES ON FIRE

Wow, long spring.

I reckon you'd be on a hiding to nothing that a spring as long and narrow as that one is sooner or later going to short out by either slipping off the battery centre, spiking through the insulation or bowing out or some combination of the above as looks to have happened here just looking at the apparently overheated spring end.

I'd say that sums it up.

The thread title also seems a little unfair as it implies the cell was faulty, which doesn't seem to be the case.

 

[hoongern]

Re: AW "Protected" Battery CATCHES ON FIRE *pics updated*

EDIT: apparently these are not protected. For some reason I got the impression these where protected... Why the hell do these cost $15 a piece then?

They aren't protected because they are IMR cells, different from your regular LiCo cells. (They use manganese instead of cobalt) They are able to be used at very high current discharge rates, not normally needing protection.

They are safer than your regular cells. In this case, they only caught fire. With [unprotected] LiCo cells, I would bet that they'd have exploded rather than just catch fire.

Anyway, that spring is REALLY long. I'm pretty sure it bent itself and somehow caused that cell to short circuit. I myself have had a short circuit with IMR cells with a positive-end spring (with a D26/P60 drop-in), so it can definitely happen.

 

[SmurfTacular]

Re: AW "Protected" Battery CATCHES ON FIRE

I'd say that sums it up.

The thread title also seems a little unfair as it implies the cell was faulty, which doesn't seem to be the case.

At the time I thought they where protected, witch is why I put protected in quotes.

I'll admit fault to this.

They aren't protected because they are IMR cells, different from your regular LiCo cells. (They use manganese instead of cobalt) They are able to be used at very high current discharge rates, not normally needing protection.

They are safer than your regular cells. In this case, they only caught fire. With [unprotected] LiCo cells, I would bet that they'd have exploded rather than just catch fire.

Anyway, that spring is REALLY long. I'm pretty sure it bent itself and somehow caused that cell to short circuit. I myself have had a short circuit with IMR cells with a positive-end spring (with a D26/P60 drop-in), so it can definitely happen.

Thanks for the info. I didn't really know what IMR was.

what the hey, you just learned one more thing , adjust thinking of the possibilities and DO IT again.



making sure that can never happen again in anything you do ever again in your whole life

And that lesson is worth more than $15

 

[Mr Happy]

Re: AW "Protected" Battery CATCHES ON FIRE *pics updated*

That spring is crazy long.

Before you make a modification you need to think through in your mind really carefully all the things that could go wrong with it, and all the ways it could fail to work as intended.

With a long spring like that, imagine that it could bend, twist, turn, buckle and generally go anywhere except in the center of the cell. It is a short circuit waiting to happen.