liveforphysics
100 TW
Punx0r said:
With a low C rate cell and the right electrolyte 4.35v is not so bad. On a power cell it can be a lot different.
Plating metallic lithium during "trickle" charge? A myth?
- Thread starter Overclocker
- Start date
With a low C rate cell and the right electrolyte 4.35v is not so bad. On a power cell it can be a lot different.
Overclocker
10 kW
while playing with various cells in parallel i realized that cells in the parallel group do micro-charging with each other since they can't be all perfectly matched
so that rules out micro-charging as being detrimental to li-ion health
as for "don't trickle or else you'll get lithium plating" that's always bandied about, it could have been spoken of in the context of older battery chemistries. i.e. "trickle" could mean low-current at slightly higher voltage say 4.30v?
reasons for li-ion charge ICs doing c/10 to c/20 cutoff:
1) a "standard" way of defining full charge i.e. not too long or else the consumer gets impatient waiting for the FULL CHARGE signal
2) cheap way of staying within safety limits. components only need 1% precision
3) shut down charging subsystem to save power etc, instead of "floating" the li-ion cell continuously
that's what i'm going to believe is true until someone can tell me a better explanation 8)
so that rules out micro-charging as being detrimental to li-ion health
as for "don't trickle or else you'll get lithium plating" that's always bandied about, it could have been spoken of in the context of older battery chemistries. i.e. "trickle" could mean low-current at slightly higher voltage say 4.30v?
reasons for li-ion charge ICs doing c/10 to c/20 cutoff:
1) a "standard" way of defining full charge i.e. not too long or else the consumer gets impatient waiting for the FULL CHARGE signal
2) cheap way of staying within safety limits. components only need 1% precision
3) shut down charging subsystem to save power etc, instead of "floating" the li-ion cell continuously
that's what i'm going to believe is true until someone can tell me a better explanation 8)
Alan B
100 GW
Trickle charging is defined as low current charging without voltage limiting, the current continues while the voltage increases. The lack of voltage limiting (or a too-high voltage limit) is the problem for lithium.
Overclocker
10 kW
Alan B said:
that's exactly the problem. "trickle charging" isn't a technical term so it depends on what context you're using it.
