Rechargeable battery module and battery charging method

摘要

An embodiment of the invention provides a rechargeable battery module including a battery bank having serial connected battery units, a charging transistor providing a charging current to the battery bank, a balancing circuit for detecting and balancing voltage values of battery units and battery bank and a control chip. When a first voltage value of a first battery unit reaches a charge-off voltage, the control chip estimates a first unbalanced voltage difference between the first voltage and the minimal voltage among battery units. The control chip disables the charging transistor and estimates a second unbalanced voltage difference between voltages of the first battery unit and the battery unit having a minimal voltage. The control chip enables the balancing circuit to balance the first battery unit. When the voltage of the first battery is dropped by a calibration target, the charging transistor is enabled.

主权项

1. A rechargeable battery module, comprising:
a battery bank having serial connected battery units; a charging transistor providing a charging current to the battery bank; a balance circuit coupled to the battery to detect and to balance voltage values of the battery units and the battery bank; and a control chip receiving the voltage values of the battery bank and the battery units, when a first voltage value of a first battery unit among the battery units reaches a charge-off voltage value, the control chip estimating a first unbalanced voltage difference and then disabling the charging transistor to stop providing the charging current, wherein when the charging transistor is disabled, the control chip estimates a second unbalanced voltage difference, and then enables the balance circuit to balance the voltage value of the first battery unit, and when the voltage value of the first battery unit is balanced for a calibration target, the control chip enables the charging transistor, wherein the first unbalanced voltage difference is between the first voltage value and a first minimum voltage value among the voltage values of the battery units before the charging transistor is disabled, and wherein the second unbalanced voltage difference is between a second voltage value of the first battery unit and a second minimum voltage value among the voltage values of the battery units after the charging transistor is disabled, and the calibration target relates to the first unbalanced voltage difference and the second unbalanced voltage difference.