Constant current charging is a method of continuously charging a rechargeable battery at a constant current to prevent overcurrent charge conditions.
What happens when a battery is charged in constant voltage mode?
During the constant voltage mode, the charging current starts to decrease. When the charging current drops to a predefined minimum current value (e.g., 0.05 C), the charging process concludes, indicating the battery is fully charged (e.g., battery state of charge is 100%).
Constant current (CC) charging initially allows the full current of the charger during the BULK stage to flow into the battery regardless of the battery state of charge or the temperature until the battery terminal voltage reaches a pre-set steady state. The battery is now in a state of charge of >80%.
How do you charge a battery?
There are three common methods of charging a battery: constant voltage, constant current and a combination of constant voltage/constant current with or without a smart charging circuit. Constant voltage allows the full current of the charger to flow into the battery until the power supply reaches its pre-set voltage.
What is the difference between constant current charging and constant voltage charging?
Constant current charging is a method of continuously charging a rechargeable battery at a constant current to prevent overcurrent charge conditions. Constant voltage charging is a method of charging at a constant voltage to prevent overcharging. The charging current is initially high then gradually decreases.
When does a CC-CV battery switch to constant voltage?
The charging switches to constant voltage (4.2 V) when the battery's internal voltage exceeds or equals 4.2 V. The process concludes when the charging current drops below 0.05 C. Figure 13 and Figure 14 illustrate the charging profile and flowchart of the Type III CC-CV charging method.
Constant current is a simple form of charging batteries, with the current level set at approximately 10% of the maximum battery rating. Charge times are relatively long with the disadvantage that the battery may overheat if it is over-charged, leading to premature battery replacement. This method is suitable for Ni-MH type of batteries.