If this is the wrong forum feel free to move it....
My DS lite cell has swollen enough to bulge the cover out a bit. I have taken it out and its sitting outside...from all the threads I've read on LiIon cells I know that swelling is bad...but can't find a definitive answer as to the gas that's produced I am not going to try and charge it. Anyway, I am pretty sure it's hydrogen that's swollen it, my main question is, is it the charger that's done it, or just a worn out cell? It's about 3 and a half years old now....
If you have used it a lot (>100 cycles) the battery is probably just worn out. I see those types of cells all the time on heavily used laptop packs. Definitely don't charge or use it anymore. If you buy a second battery and it puffs up not long after using it, then I would suspect a faulty charging circuit. The gas inside that makes it puff up is Carbon Dioxide. Li-Ion has Di-Ethylene Carbonate (DEC) and Ethylene Carbonate (EC) as solvents inside. Those two compounds tend to break down give off Carbon Dioxide when the battery nears the end of life. I still wouldn't want to have ignition sources near them though as both DEC and EC are highly volatile and flammable.
Thanks, I have replaced it and it's working fine now, the other cell has been recycled...really don't need my best source of entertainment going besides from here of course