Today, upon periodic inspection of a light that doesn’t see regular usage, I discovered the condition below.
The dark deposits are hard, and perhaps crusty.
The lighter deposits that look like grease can be smeared a bit, like a thick grease. However, it isn’t excess lube from the threads or anything of that nature.
The spring cleaned up fine with some contact cleaner, and wasn’t corroded like one would see with alkalines.
Can’t say when the cell was manufactured, but the light it was bundled with was obtained ten months ago in October 2019.
I’ve never experienced a leaking Li cell before, so I’m trying to get a better understanding of the situation. But, my overall experience suggests that unexpected secretions are not good things, for either people or batteries.
I would probably toss safely recycle it. Especially given that a new 18650 of reputable quality is $5 to $10. It’s a lot of risk over $10.
If you really want to try to salvage it, I’d say to test it first and observe it the whole time. So, measure voltage now, then capacity and internal resistance, and make judgements based on that.
