whatever
100 kW
- Joined
- Jun 3, 2010
- Messages
- 1,297
just looking into formation charging regimes for nmc type lithiums.
an interesting paper showing how to shorten formation charging times can be seen here:
https://www.sciencedirect.com/science/article/pii/S0378775317300113
this pic sums up the method
https://ars.els-cdn.com/content/image/1-s2.0-S0378775317300113-gr2_lrg.jpg
basically they charge up to approx 4.2v at c/5 rate, but only discharge down to 3.9v about 5 times, instead of discharging down below 3.9 volts. Lands up produces just as good capacity as longer methods with good sei layer produced.
Reason I'm interested in this ( as I have posted some time ago), there is possibility of flushing old cells with ec:dc:emc or similar electrolyte can remove sei layer of an old cell, then replacing with new lipf6 electrolyte and formation charging can get cell back to near original condition.
Unfortunately these electrolytes are expensive for diy people.
an interesting paper showing how to shorten formation charging times can be seen here:
https://www.sciencedirect.com/science/article/pii/S0378775317300113
this pic sums up the method
https://ars.els-cdn.com/content/image/1-s2.0-S0378775317300113-gr2_lrg.jpg
basically they charge up to approx 4.2v at c/5 rate, but only discharge down to 3.9v about 5 times, instead of discharging down below 3.9 volts. Lands up produces just as good capacity as longer methods with good sei layer produced.
Reason I'm interested in this ( as I have posted some time ago), there is possibility of flushing old cells with ec:dc:emc or similar electrolyte can remove sei layer of an old cell, then replacing with new lipf6 electrolyte and formation charging can get cell back to near original condition.
Unfortunately these electrolytes are expensive for diy people.