Lithium batteries are generally capable of charging and discharging 300-500 times. It is best to partially discharge the lithium battery instead of completely discharging it, and try to avoid frequent full discharges. Once the battery is off the production line, the clock begins to move. Whether you use it or not, the life of a lithium battery is only in the first few years. The decrease in battery capacity is due to an increase in internal resistance due to oxidation (this is the main cause of battery capacity degradation). Finally, the cell resistance will reach a certain point, although the battery is fully charged, the battery cannot release the stored charge.