Charging Method of 18650 Lithium Battery
18650 lithium battery charging methods
1. High voltage charging
This charging method does not have a special control circuit. It directly uses the 5V power supply to charge the battery with the protection board, completely relying on the high voltage limit of the protection board.
The characteristic is that the current is very large at the beginning, and then gradually decreases, and it can be floated at any time. Most of the charging methods that will explode are this kind, which is common in low-end card MP3 and so on.
2. Constant voltage charging
This method is similar to the previous one. The constant voltage is actually the limited voltage. That is to set a relatively accurate maximum voltage, and then keep charging at that voltage until it reaches 4.2V.
If this kind of charger makes the cut-off voltage very accurate, it will be fine, and it will be safe if it is low.
But if it is too high, it must rely on the protection board. As for the bare battery, it cannot be said to be safe.
3. Constant current charging
This charging method limits the maximum charging current.
Constant current and constant voltage is actually limited current and pressure. This kind of circuit is more popular.
After being fully charged, it is not completely cut off. Instead, it is changed to floating charge.
It is now believed that long-term low-current charging is one of the reasons for the flatulence of the 18650 lithium battery.
4. Smart charging
This is now considered an ideal charging management method.
Following the charging algorithm mentioned at the beginning of this section, it is integrated in a small chip IC. And the peripheral circuit is simple, stable and reliable.
The important feature of this chip is that it will monitor the voltage and current at the same time when judging whether it is full, and stop charging at 4.2V. Or the charging current is too small to 0.01C (usually about 50mA) to stop charging.
It is completely cut off after full, there is no floating charge, but the voltage is monitored at any time.
At this time, the capacity is lower than the normal value, and the use time is also shortened accordingly.
However, lithium-ion batteries are easy to activate, and the battery can be activated after 3-5 normal charge and discharge cycles, and the normal capacity can be restored.
Due to the characteristics of the dry lithium-ion battery itself, it has almost no memory effect.