What if the lithium battery is long enough to charge?

We know that lithium batteries do not have the "memory effect" like nickel-chromium batteries. Nowadays, what we often see is basically lithium batteries. 18650 is also a type of lithium battery. After a long period of time without batteries, the battery will be found to be uncharged. This is due to over discharged, which means the battery voltage is already lower than the cut-off voltage of the battery discharge, and it is generally about 2.5 V for the general lithium battery.

What should be done with batteries that are not used for a long time or have a low discharge voltage, and can they be activated? When it comes to activation, many lithium cells do not exist as a single cell, but as a battery pack. Then there is generally a charge management board, the main part of which is the charge management IC. This IC has overcharge, overdischarge, Overflow, short circuit and other protection functions. For lithium battery discharge will set a minimum limit, placing the battery over the lead to an irreversible reaction, that is to say, our battery can not rush into the charge for a long time is the truth. Then sometimes you can try using the "activation" method.

Lithium battery charging generally uses the "constant current-constant pressure" method, which means that the standard current is used first for a period of time, and constant voltage charging is used when the battery voltage reaches the charging cut-off voltage. Therefore, DC power can be used for a period of time, and the original charger can be recharged when the cut-off voltage is reached. Although this method is sometimes feasible, it is not always possible. After all, the over discharge of the battery has affected the performance of the battery. However, there are also cases where batteries that have been placed for several years can also be activated.

So how do you maintain lithium batteries?