The constant current charging stage process of battery charger

Constant current charging is a key stage in the battery charging process. It is performed when the charger provides a fixed current to the battery. The main goal of this stage is to deliver charge to the battery at the greatest possible speed, allowing the battery to quickly reach its maximum charge capacity.

Current control:

In the constant current charging stage, the battery charger delivers charge to the battery by controlling the current. The amount of current depends on the size and design of the battery.

Typically, a battery's maximum charge rate is a certain percentage of its capacity to avoid excessive heat generation and other safety issues. Therefore, the current value is set to this maximum charging rate.

Voltage rise:

With the input of current, the voltage of the battery gradually increases. This is because during the charging process, the chemical reaction between the positive and negative electrodes causes charge to accumulate in the battery.

For lithium-ion batteries, the voltage rise is usually smoother, but there may be a steeper rise before approaching the constant voltage charging stage.

Battery temperature control:

During the constant current charging stage, a certain amount of heat may be generated inside the battery because current passing through the battery will cause resistance. Therefore, battery chargers need to monitor and control the temperature of the battery.

Temperature control is critical to prevent overheating, as excessive heat can damage the battery's structure and performance.

Termination condition:

The constant current charging phase typically continues until the battery reaches a predetermined termination condition. This usually means that the battery voltage has reached its maximum allowed value, or some parameters inside the battery indicate that the battery is fully charged.

Termination conditions for lithium-ion batteries are usually when the voltage reaches a specific threshold and the current drops to a predetermined percentage, indicating that the battery has become saturated.