Old Li-po Scary Tricks

[ecookman]

SO I have an old Archos 404 Diagial media center (I have had it for almost 4 years).
Over the last week or so, I have noticed that the charge isn't holding at all. But that could have been because I have only been half charging it.

BUT today was another story. I decided to FULLY charge the battery (slow charge via USB) so I could listen to music as i fell asleep.
When I went to turn it on the indicator showed full battery, but in 5 minutes, the player shut off. Weird right?
In frustration i placed it on my desk, and in about 3 minutes i heard it make a little snap noise...The back cover which is made of aluminum somehow became bent and was forced off of two clips it is seated on. Then it hit me, the only thing that could expand in the player WAS THE LI-PO!!!! Quickly removing the back case I found a Li-po battery (1cell) that had expanded from a mere 5 millimeters to 1cm. Quickly running outside, I cut the battery wires, removed the battery from the player and burred the battery in a bucket of sand I have. (if you have ever seen a Li-Po get big and explode...you'll understand why I am so panicked). While I was doing this...I could literally see the battery growing.

Does anyone have any idea as to how this could have happened? I have devices older and that are used about the same as my Archos, but the battery is fine. I am at a loss...So if the Li-* battery hypotheses gods/masters can give me some knowledge, that would be great.

[SNIPERDUDE]

Something must have shorted it.

[Euphoracle]

yeah, you charged it incorrectly. dont do that

[DtY]

The only time I've heard of this happening was cheap batteries that were made cheaply.

But if that was the case, I'd expect it would have happened sooner.

[SNIPERDUDE]

Perhaps it was the half-charging that caused the problems. If it did something weird like, set the 'max hold' lower than it should be or if some limit-cap is removed...

[ecookman]

If that was the case, wouldn't the battery just not charge as much? It automaticaly stops charging the battery when it detects its full.
ALSO the battery continued to expand when it was cut off of the player. Is it possible for them to short internaly?

Another theroy I had was (if this is correct). As mentioned, could the half charging and discharging, cause something chemicaly to go wrong?

[SNIPERDUDE]

These types of batteries can be shorted internally, you don't even need to charge them to do it either. Though this is usually caused by some internal physical damage.