The charging process suitable for lithium ion batteries can be divided into four stages: trichide charging, constant current charging, constant voltage charging and charging termination.

Phase 1: Target charging -trickle charging is used to pre -charged (recovery charging) for battery units that are completely discharged. When the battery voltage is less than 3V, the battery is charged with a constant current of 0.1C.

The second stage: Hengli charging -when the battery voltage exceeds the trickle charging threshold, increase the charging current of Hengli charging. The Hengliu charging current is between 0.2 ~ 1.0C. The current of Hengliu charging does not need to be very accurate, and it can be used in accordance with Hengliu. In the design of the linear charger, the current often increases as the battery voltage increases, so as to minimize the heat dissipation problem of transmitting transmission transmission.

Hengli charging is greater than 1C, which does not shorten the entire charging cycle time, so this method is not desirable. When the charging current is large, the battery voltage rises faster due to the impact of excessive voltage and voltage of the electrode reaction on the battery internal impedance. The constant current charging phase will be shortened, but the total charging cycle time will not be shortened due to the corresponding increase in the next constant voltage charging stage.

The third stage: constant voltage charging -when the battery voltage rises to 4.2V, the constant current charging ends and the constant voltage charging begins. In order to achieve better performance, the voltage tolerance should be greater than+ 1%.

Phase 4: End of charging-Unlike nickel batteries, lithium-ion batteries that are continuously tricked current charging are not recommended. Continuous dripping charging can cause electroplating effect on the metal lithium plate. This may make the battery unstable, and may cause suddenly automatic and rapid disintegration.

There are two typical charging termination methods: using small charging current to judge or use timer (or two combinations). Small current method monitor the charging current during the constant voltage charging phase, and the charging current is terminated when the charging current is reduced to 0.02 ~ 0.07C. The second method calculates the start of the constant voltage charging phase, and the charging process is over after two consecutive hours of charging.

The above four -stage charging method is used to charge the battery. The entire discharge process takes about 2.5 to 3 hours. Advanced chargers also use more security measures. For example, if the battery temperature exceeds the specified window (usually 0 to 45 degrees Celsius), the charging will be paused.