Hey guys,

I have a simple question with a maybe not so simple answer. How do battery powered devices prevent leakage currents from destroying its own lithium battery?
Say a phone that hasbeen left few years in a drawer. You can just charge it back up and its fine. I find that most semiconductor devices have a leakage current, so how do companies get around this limitation?
I was thinking using a relay is a solution but I doubt all our electronic devices use relays. Does anybody know what the solution that is used for this problem? Also my other question is, in a battery protection circuit,say on an 18650 battery, how are the mosfets kept open, which would obviously drain the battery until it dies.?

 

For most devices he leakage is so low that the company figures you will charge it up before the battery gets so low as to damage it.
If you don't use the device for a few years and the battery dies I don't think they are concerned about that.

 

For most devices he leakage is so low that the company figures you will charge it up before the battery gets so low as to damage it.
If you don't use the device for a few years and the battery dies I don't think they are concerned about that.

That's probably about right - and rechargeable lithium cells have a finite life expectancy whether you use them or not. Could be as short as 5yrs with some types.