Li-ion protection breakdown voltage?

  • Thread starter Artlav
  • Start date
  • #1
162
0
Li-ion cells come with undervoltage protection circuits - little integrated thingies that open up the circuit when the voltage across the cell drops below 2.7V or so.
What sort of a switch is that?

I've been thinking, if a cell is inside a large series pack - a dozen of cells for a hobbyist, or a hundred cells for an electric car - won't that switch be subjected to the entire voltage of the pack upon it's opening for the weakest cell?

If so, what is the breakdown voltage of these switches, i.e. in 18650 cells, where can i look it up?
If not, how does that protection work?

I never seen such figures given in battery datasheets, so maybe i've missed the big idea?
 

Answers and Replies

  • #3
162
0
Nice. So that is how you do it right.
But if you just stack a set of common, single-protected cells - what would be their limit?
 
  • #4
meBigGuy
Gold Member
2,323
405
Don't.

I've never considered it. The protection circuit design assumes you won't do that.
 

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