How to charge LiFePO4 Rechargeable Lithium Ion Batteries?
The charging method of CCCV is recommended for the charging of lithium iron phosphate battery pack, that is, constant current first and then constant voltage. How’s the detail charging process? Let’s see Bonnen engineer introduction. 0.3C is recommended for constant current. 3.65V is recommended for constant voltage. That is 0.3C current charging during the constant current. When the battery voltage reaches 3.65V, use 3.65V voltage constant voltage charging. When the charging current is less than 0.1C (or 0.05C), stop charging, that is, the battery has been full. When you charge with a balanced voltage power supply, you also need to look at the charging current. It is recommended not to charge with too high a voltage. After adjusting the voltage, ensure that the charging current is below 0.5C, which is good for the battery.
Generally, the upper limit voltage of LiFePO4 battery is 3.7V ~ 4V, the lower limit voltage of discharge is 2V~ 2.5V, considering the five aspects of discharge capacity, median discharge voltage, charging time, constant current capacity percentage, and safety, constant current and constant voltage For the charging scheme of the LiFePO4 battery pack, it is reasonable to set the charging limit voltage at 3.55 to 3.70V, the recommended value is 3.60 to 3.65V, and the lower limit discharge voltage is 2.2V to 2.5V.
The charger of the LiFePO4 battery pack is different from the ordinary lithium battery. The maximum termination charging voltage for NCM lithium batteries is 4.2 volts; the LiFePO4 battery pack is 3.65 volts. When the LiFePO4 battery pack is charged, it is a cable connected to the balance charging board. Generally, it is directly connected in series from both ends and the charger voltage is greater than the battery pack voltage. The cable detects the voltage of each cell, which is equivalent to paralleling a voltage regulator tube. The charging voltage of the cell will not exceed the voltage regulation value, while the other cell batteries continue to charge through the voltage regulator bypass charging.