Device and method for achieving dynamic charging and balance of battery cells and rechargeable battery device

A device for achieving dynamic charging and balance of battery cells is disclosed. The device is configured for monitoring a plurality of battery voltages from a plurality of battery cells in a multi-cell battery pack. In case of a battery voltage difference between two of the battery cells being greater than a pre-determined voltage difference, the device generates a plurality of balance charging currents for charging the battery cells. In which, each of the balance charging currents is calculated based on remaining charge time, measured battery voltage, and rated battery capacity. Thus, in a charge cycle, one balance charging current for charging the battery cell with low battery voltage is designed to be greater than another one balance charging current for charging the battery cell with high battery voltage. Consequently, elimination of the battery voltage difference existing between any two of the battery cells is achieved.