During charging and discharging of a battery, the voltage across it varies in a characteristic manner. Let's explore the voltage changes in both processes:
When a battery is being charged, electrical energy is supplied to it from an external power source, typically a charger. During this process, the voltage across the battery gradually increases. The charging voltage depends on the battery chemistry and the charging method used.
At the beginning of the charging process, the battery voltage is lower, and as more charge is added to the battery, the voltage rises. It reaches its peak when the battery is fully charged, and at this point, the charger typically reduces the charging current to prevent overcharging.
It's essential to monitor the charging process and cut off the power supply once the battery is fully charged to avoid damaging the battery or creating safety hazards due to overcharging.
When a battery is being discharged, it is providing electrical energy to an external device or circuit. As the battery releases stored energy, its voltage gradually decreases.
Similar to charging, the discharge voltage also depends on the battery chemistry and the current draw from the external load. As the battery's charge depletes, the voltage decreases steadily until it reaches a minimum threshold, often referred to as the cutoff voltage.
The cutoff voltage varies for different types of batteries and is a critical parameter to consider. If a battery discharges beyond its cutoff voltage, it can lead to irreparable damage and permanent capacity loss.
It's important to note that both charging and discharging processes are not 100% efficient, and some energy is lost as heat due to internal resistance within the battery.
In summary, during charging, the battery voltage gradually increases until it reaches its maximum when the battery is fully charged. During discharging, the battery voltage gradually decreases as it provides electrical energy to an external device until it reaches its minimum cutoff voltage.