In the course of my work, today I was handed a defunct Apple Mac laptop.
The person commented "BTW the battery is bulging a bit"
Within 2 hours I had 3 Mac LiIOn batteries with bulges. One so extreme that the casing fell apart in my hands.
After a chat with the university fire officer, these are now in "secure containment" outside the building (a metal bin away from anything flammable).
I realise the risk of spontaneous combustion is very slim, but if it did happen in an office context it would make up for that by the badness of what would happen. This was exactly our fire officers thinking - no need to panic, but let's just mitigate against anything really bad happening...
So - what has likely happened to cause the cells to bloat? In the one where the case fell apart, one cell felt very gassy.
These batteries are around 8 years old plus/minus a year.
In reality - are they likely to be a risk? I assume, with LiIon the risk would only exist if the cells were charged rather than flat - no metallic lithium unlike lithium primary cells.
I must admit I have never seen an LiIon pack do this - but then I tend to throw my old crap out before it gets that old... In England, (and the EU) we have to follow the correct disposal/recycling process which means stuff often gets hoarded until someone like me comes along and books a big disposal...
I am also not sure why it all seemed to be Apple stuff - they are not known for being "cheap". So I'm thinking it must be a little more generic in cause.
Cheers for any thoughts...