Phase 1: Trickle Charge Trickle charge is used to pre-charge fully discharged cells first (recovery charge). When the battery voltage is lower than about 3V, trickle charging is used, and the trickle charging current is one-tenth of the constant current charging current, that is, 0.1c (for example, the constant charging current is 1A, the trickle charging current is 100mA).
Stage 2: Constant current charging When the lithium-ion battery pack voltage rises above the trickle charging threshold, increase the charging current for constant current charging. The current for constant current charging is between 0.2C and 1.0C. The battery voltage gradually increases with the constant current charging process. Generally, the voltage set by a single battery is 3.0-4.2V.
Phase 3: Constant voltage charging When the voltage of the lithium-ion battery pack rises to 4.2V, the constant current charging ends and the constant voltage charging phase begins. According to the saturation degree of the cell, the charging current gradually decreases from the maximum value as the charging process continues. When it decreases to 0.01C, the charging is considered to be terminated.
Stage 4: Charge Termination There are two typical methods of charge termination: use a minimum charge current judgment or use a timer (or a combination of the two). The minimum current method monitors the charging current during the constant voltage charging phase and terminates charging when the charging current is less than 0.02C. The second method counts the start of the constant voltage charging phase and terminates the charging process after two hours of continuous charging.
Therefore, in the matter of charging the battery, we must choose a dedicated charger to charge the corresponding battery to prevent mixed use, hidden safety hazards or accidents. The charging method of lithium iron phosphate battery pack is constant current and constant voltage charging, and the charging method of lead-acid battery is pulse, so different batteries cannot share the charger.
