The charging process of a lithium-ion battery pack:
The charging process of lithium-ion batteries can be divided into four stages: trickle charging (low-voltage pre-charging), constant current charging, constant voltage charging, and charging termination.
1. Trickle charging is used to pre-charge fully discharged battery cells. Trickle charging is used when the voltage of a lithium-ion battery pack is below approximately 3V. The trickle charging current is one-tenth of the constant current charging current, i.e., 0.1c.
2. When the lithium-ion battery voltage rises above the trickle charging threshold, the charging current is increased to perform constant current charging. The constant current charging current is between 0.2C and 1.0C. The lithium-ion battery voltage gradually increases during the constant current charging process; typically, this voltage is set to 3.0-4.2V for a single cell.
3. When the lithium-ion battery pack voltage rises to 4.2V, constant current charging ends and constant voltage charging begins. The current decreases gradually from its maximum value as charging continues, depending on the cell's saturation level. Charging is considered complete when the current decreases to 0.01C.
4. Two typical methods for terminating charging: using the minimum charging current or using a timer. The minimum current method monitors the charging current during the constant voltage charging phase and terminates charging when the charging current decreases to the range of 0.02C to 0.07C. The second method starts timing at the beginning of the constant voltage charging phase and terminates the charging process after two hours of continuous charging.
Precautions when charging lithium-ion batteries:
1. Charge in a timely manner
Lithium-ion battery packs should be charged as soon as possible after use to keep the battery fully charged.
2. Periodic deep discharge
Performing a deep discharge periodically on a lithium-ion battery pack can also help "activate" the battery, slightly increasing its capacity. A common method is to periodically perform a complete discharge of the battery.
3. Use the original charger whenever possible.
Generally, avoid changing the charger if you are not sure, as this will reduce the lifespan of the lithium-ion battery pack.
4. Pay attention to the charging environment.
The optimal ambient temperature for charging lithium-ion battery packs is 25℃. Most chargers currently lack automatic temperature control systems, so they are designed for an ambient temperature of 25℃. Therefore, charging at 25℃ is preferable.
5. Frequent use
Life lies in movement. To maximize the efficiency of a lithium-ion battery pack, it needs to be used frequently to keep the electrons within the lithium battery constantly in a state of flux.
