The internal resistance of the direct current (DC) battery plays a crucial role in the charging process by causing voltage drops, power losses, and affecting the charging speed and efficiency. As shown in Fig. 6 (d), the internal resistance of a battery varies constantly during the charging process.
Understanding The Battery Charging Modes: Constant Current and Constant Voltage Modes Charging is the process of replenishing the battery energy in a controlled manner. To charge a battery, a DC power source with a voltage higher than the battery, along with a current regulation mechanism, is required.
Charging is the process of replenishing the battery energy in a controlled manner. To charge a battery, a DC power source with a voltage higher than the battery, along with a current regulation mechanism, is required. To ensure the efficient and safe charging of batteries, it is crucial to understand the various charging modes.
Charging voltage = OCV + (R I x Battery charging current limit) Here, R I is considered as 0.2 Ohm. Observing the below picture, it becomes evident that the DC power source regulates its charging voltage in accordance with the charging current limit.
As the State of Charge (SOC) increases, the battery charging current limit decreases in steps. Additionally, we observe that the battery voltage increases linearly with SOC. Here, Open Circuit Voltage (OCV) = V Terminal when no load is connected to the battery. Battery Maximum Voltage Limit = OCV at the 100% SOC (full charge) = 400 V.
The lithium battery charging curve illustrates how the battery’s voltage and current change during the charging process. Typically, it consists of several distinct phases: Constant Current (CC) Phase: In this initial phase, the charger applies a constant current to the battery until it reaches a predetermined voltage threshold.