What is the charging process of lithium batteries?

Detailed explanation of the charging process of lithium batteries The most suitable charging process for lithium batteries can be divided into four stages: trickle charging, constant current charging, constant voltage charging and charging termination. Refer to Figure 1. Phase 1: Trickle charge Trickle charge is used to pre-charge the fully discharged battery cell (recovery charge). When the battery voltage is lower than about 3V, first charge the battery with a constant current of maximum 0.1C. Phase 2: Constant current charging When the battery voltage rises above the trickle charge threshold, increase the charging current for constant current charging. The current for constant current charging is between 0.2C and 1.0C. The current during constant current charging is not required to be very accurate, and quasi-constant current is also acceptable. In the linear charger design, the current often rises as the battery voltage rises to minimize the heat dissipation problem on the pass transistor. Constant current charging greater than 1C will not shorten the entire charging cycle time, so this approach is not advisable. When charging with a higher current, the battery voltage will rise more quickly due to the overvoltage of the electrode reaction and the voltage rise on the internal impedance of the battery. The constant current charging phase will be shorter, but since the time of the constant voltage charging phase below will be increased accordingly, the total charging cycle time will not be shortened. Phase 3: Constant voltage charging When the battery voltage rises to 4.2V, the constant current charging ends and the constant voltage charging phase begins. To maximize performance, the voltage regulation tolerance should be better than +1%. Stage 4: Charge termination is different from nickel batteries, and it is not recommended to continue trickle charging of lithium batteries. Continuous trickle charging will cause the plate plating effect of metallic lithium. This will make the battery unstable and may cause a sudden automatic quick disassembly. There are two typical charging termination methods: using the minimum charging current to determine or using a timer (or a combination of the two). The minimum current method monitors the charging current in the constant voltage charging stage, and terminates the charging when the charging current decreases to the range of 0.02C to 0.07C. The second method starts from the constant voltage charging phase and ends the charging process after two hours of continuous charging. The above-mentioned four-stage charging method takes approximately 2.5 to 3 hours to charge a fully discharged battery. Advanced chargers also adopt more safety measures. For example, if the battery temperature exceeds the specified window (usually 0°C to 45°C), then charging will be suspended. After reading the above analysis, I have a good idea about the correct charging method of lithium battery. From the charging curve chart of lithium battery, it can also be seen that the charging process of lithium battery is divided into 4 stages. According to the characteristics of each stage, we can not only do it. Use the lithium battery correctly, and better protect the lithium battery to prevent improper operation that may cause damage to the lithium battery. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete it.