Difference of constant current charging, constant voltage charging and constant current and voltage-limited charging

 There are various charging methods for electric vehicles, among which constant current charging, constant voltage charging and constant current and voltage-limited charging are the three most common methods. Each of them has unique characteristics and differences.

Constant current charging refers to a charging method in which the current is maintained at a constant value. This method is widely used in the charging process of various batteries. The advantage is that the charging current value can be determined based on the battery capacity, the charging amount can be directly calculated and the time to complete charging can be determined. At the same time, the current of constant current charging can be selected arbitrarily, which is beneficial to extending the service life of the battery. However, the constant current charging method requires frequent adjustment of the charging voltage and takes a long time to charge.

Constant voltage charging refers to a charging method that keeps the charging voltage constant during the charging process. The advantage is that the charging time is short and the voltage does not need to be adjusted during the charging process, making it more suitable for supplementary charging. In addition, constant voltage charging can automatically adjust the charging current as the battery's state of charge changes. If the specified voltage constant value is appropriate, it can not only ensure the battery is fully charged, but also minimize gas evolution and water loss. However, the disadvantage of constant voltage charging is that it is not easy to fully charge the battery, and if the battery is discharged too deeply in the early stages of charging, the charging current will be very large, which may endanger the safety of the charger, and the battery may also be damaged due to overcurrent.

The constant current and voltage limiting charging method combines the characteristics of constant current charging and constant voltage charging. It first charges in a constant current mode. When the battery pack terminal voltage rises to the voltage limit value, the charger automatically switches to constant voltage charging until the charging is completed. This method can not only ensure the stability of the charging current, but also avoid overcharging problems caused by excessive voltage, which is beneficial to protecting the battery.

In general, these three charging methods have their own advantages and disadvantages and are suitable for different charging scenarios and needs. In practical applications, the appropriate charging method should be selected according to the type, status and charging needs of the battery.