Do 18650 batteries need to be activated?

Do 18650 batteries need to be activated?

Lithium ion battery cases are filled with electrolyte, sealed, and transformed into batteries. This process involves constant voltage charging, followed by discharge, and repeated for several cycles to fully immerse the electrodes in the electrolyte and activate them until the required capacity is achieved. This is the activation process - capacity division, which tests the capacity of the battery by selecting batteries with different performance (capacity) for classification, grading, and capacity matching. The lithium-ion battery produced in this way has already been activated by the user. The nickel cadmium batteries and nickel hydrogen batteries that we commonly use are also activated before leaving the factory. The activation process of some of these batteries requires the battery to be in an open state, and then sealed after activation. This process can only be completed by the battery cell manufacturer.

There is a problem here, that is, the time it takes for batteries from the factory to reach the hands of users can sometimes be very long, ranging from as short as one month to as long as six months. At this time, due to the passivation of battery electrode materials, manufacturers recommend that first-time batteries undergo 3-5 complete charge and discharge processes to eliminate passivation of electrode materials and achieve maximum capacity.

Three regulations on nickel hydrogen were issued in 2001. In the national standards for nickel cadmium and lithium-ion batteries, there are clear provisions for the initial capacity testing. The battery can be deeply charged and discharged 5 times, and the test can be stopped when one of them meets the requirements. This explains the phenomenon I mentioned very well.

It is also possible to call it "second activation", and users should try to perform several deep charging and discharging cycles on the "new" battery they are using for the first time.

However, according to my testing (for lithium-ion batteries), there is almost no increase in capacity when lithium-ion batteries with a storage period of 1-3 months are subjected to deep charging and deep discharging cycles.