METHOD OF MAKING LITHIUM ION BATTERIES

摘要

A method for activating lithium ion batteries related to the initial formation cycle (initial battery break in prior to use) is used to improve battery performance. The method involves charging the battery for the first time after being fabricated, to an initial voltage Vi that is above 4.25 Volts vs Li/Li+, but less than 5 Volts. The battery is discharged to a base voltage Vb that is from 4.15 to 4.25 Volts and held at Vb for a period of time that is at least one minute to at most several weeks. The battery is then charged to a final voltage Vf that is greater than Vb. The batteries activated by the method may have one or more improved properties such as longer cycle life, greater capacity at higher charge/discharge rates or consistent performance from battery to battery.

主权项

1. A method of performing the formation cycle of a lithium ion battery, comprising:
(A) charging, for the first time after being fabricated, a lithium ion battery comprised of a lithium rich cathode to an initial voltage Vi that is above 4.25 volts vs Li/Li+, but less than 5 volts; (B) discharging the lithium ion battery to a base voltage Vb that is from 4.15 to 4.25 Volts; (C) holding the lithium ion battery at Vb for a period of time that is at least one minute to at most several weeks; and (D) charging the lithium ion battery to a final voltage Vf that is greater than Vb and less than 5 volts.