Swollen battery (9798)

[EvilTwin]

Hello

Recently I bought a Mindstorms NXT programmable brick plus a rechargeable battery 9798 from someone on eBay. What the seller didn't mention is that the battery is slightly swollen. You can just about make it out in this terrible picture (sorry) :

20140918_193625 by freshfroot1, on Flickr

So basically is has a slightly rounded top and bottom. I know that swelling up is normal for some batteries of this type and age (there are many cases of Apple MacBooks that have basically burst apart because of the same problem).

It's not too bad yet and the battery still holds a charge. But I'd be interested to know if anyone else has experienced something similar, and if so, if it is possible to predict how long the battery will last. I know this could probably be a random number but I would be interested in others' experience anyway. Also what happens if it gets worse- does the battery split apart, just simply fail, explode dramatically?

I'm not really bothered about it because the price I paid was about average for the NXT brick by itself. Also I'd expect it to be very unlikely that Lego would replace it, since it is probably several years old, is discontinued (replaced by 9693) and is probably counted as a consumable item anyway.

Thanks

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EvilTwin

[Blakbird]

A lithium battery that has swelled has been either overcharged or overdischarged. Either way it should be considered ruined. I'd ask for a refund. If whatever fault caused the condition is in the battery and not in the charging system, then it could in fact explode when it is charged.

[Agent Fusion]

Well, that's worrying.

[Balrog]

Don't charge it. Don't use it. Simply get rid of it.

I have seen defects like this multiple times. Once it was a Nokia phone that was permanently on charge (in a rescue vehicle), where the battery started to swell and the case of the phone burst. Another time I had a PDA where the replacement battery was swollen after quite some time, gladly no damage, but the case had a bulge.

And then there is the famous explosive Apple battery cell which caused the devices to explode, start burning or even burned down houses.

Edited September 18, 2014 by Balrog

[Phoxtane]

Puffed batteries are an immediate 'get-rid-of-immediately' sign for anybody who does R/C simply because that's a sign that the battery could be prone to bursting out in flames and/or exploding the next time it's used - something to do with the deformation internally shorting the battery and causing a large enough energy flow in a short enough time span that the battery heats up dramatically.

[aol000xw]

Judge by yourself, you will notice the swolling and then...

[m0dulo]

I'd recommend you do not use it because it could be dangerous — and follow the ebay procedures to get a refund. You will probably have to pay return shipping. Get tracking with signature by the person it is addressed to. Delivery confirmation only is worthless.

Edited September 19, 2014 by m0dulo