Lithium batteries are in the news for all the wrong reasons at the moment, and not for the first time.
We noticed that one of our batteries was a little swollen compared to the others. It seemed to be working OK though. We decided to open up the outer wrap to see if it was one cell or all of them, and to see if anything was obviously wrong. The battery was an 11.1V 1300mAHr LIPO. Check out some pics of us cutting off the outer black covering, to reveal that all three cells were swollen. There appeared to be no external sign of damage however. The cells feel as if they are swollen with gas.
We hooked it up to the IMAX charger to see what kind of capacity our battery had. This battery is about five years old. Its nominal capacity is 1300mAHr. We fully charged it and then discharged it. We were pleasantly surprised to find it at 1095mAHr. That was discharging it at 200mA which is about C/6. By the time the charge and discharge was complete, the pack had swelled even more.
The question now is what to do with this battery. The Internet is full of videos of people doing all sorts of crazy things to lithium batteries too. We won’t be doing any of that here. We won’t be keeping this battery indoors, thats for sure. It could still be useful for some completely remote outdoor application, away from any kind of combustible material. We should probably dispose of it safely though. Note that all of the disassembly, charging and discharging was done outdoors and with lots of PPE.