So I've found myself in unexpected possession of some more or less bloated cells. As I'm going through with discussion to get my money back I'm also wondering if, with some acceptance of risk, these can be used, but also I'm interested in the topic in general.
I think quite a few people have bloated cells in operation, judging by what I found said in some old threads. So I would like to ask. How much bloating is definitely too much?
And more importantly, what is the mode of failure of these bloated cells? Let's say one was monitoring things like AC IR, and temperature (also fixture pressure if they are compressed). Is it possible to intercept such a cell before it decides to blow its valve? I'd love to at least have an opportunity to measure capacity before they are sent back.
Let's say a cell is taking a charge and is not heating up. Is it likely it may suddenly develop an internal short and "run away"?
If anyone is interested. The cells I got are mostly bloated by few mm. 2~4, the worst is about 6mm, but that one is also concave slightly on the opposite end. As if it drooped...
The voltages are 3.26V and very equal which makes me think they were equalised/charged before. (they came in 2 days after ordering).
One of my cells has also a crack on its side. Spreading it with a plastic spudger I could see pouches inside that don't look damaged, but they may well be. Surprisingly that cell is not swollen much. Maybe 1.5mm. It doesn't smell more than when I open my ammo box full of my fpv li-ion packs.
I have these cells in a worshop with a CO2 fire extinguisher nearby and not much flammable stuff around them. Just in case.
I think quite a few people have bloated cells in operation, judging by what I found said in some old threads. So I would like to ask. How much bloating is definitely too much?
And more importantly, what is the mode of failure of these bloated cells? Let's say one was monitoring things like AC IR, and temperature (also fixture pressure if they are compressed). Is it possible to intercept such a cell before it decides to blow its valve? I'd love to at least have an opportunity to measure capacity before they are sent back.
Let's say a cell is taking a charge and is not heating up. Is it likely it may suddenly develop an internal short and "run away"?
If anyone is interested. The cells I got are mostly bloated by few mm. 2~4, the worst is about 6mm, but that one is also concave slightly on the opposite end. As if it drooped...
The voltages are 3.26V and very equal which makes me think they were equalised/charged before. (they came in 2 days after ordering).
One of my cells has also a crack on its side. Spreading it with a plastic spudger I could see pouches inside that don't look damaged, but they may well be. Surprisingly that cell is not swollen much. Maybe 1.5mm. It doesn't smell more than when I open my ammo box full of my fpv li-ion packs.
I have these cells in a worshop with a CO2 fire extinguisher nearby and not much flammable stuff around them. Just in case.