Patent ID: 7759904
Filing Date: 2010-07-20
Classification: H01M,Y02E,Y02P

Abstract:
1. A battery pack having a plurality of cells, comprising: a cell group composed of a plurality of cells connected in series; a voltage detection circuit for sensing a voltage of each of the plurality of cells and outputting a total voltage; a switching unit for connecting or disconnecting the cell group and output terminals; and a controller for receiving a total voltage of at least one slave battery pack and the total voltage output from the voltage detection circuit to calculate a target total voltage, sending the calculated target total voltage to each slave battery pack, comparing the calculated target total voltage with its own total voltage, and then controlling the switching unit according to the comparison result, wherein, in case of a charging mode, the target total voltage is calculated as a target total voltage for all battery packs based on a minimum voltage for all battery packs, wherein, in case of a discharging mode, the target total voltage is calculated as a target total voltage for all battery packs based on a maximum voltage for all battery packs, wherein, in the charging mode, the target total voltage is increased step by step as time goes, and wherein, in the discharging mode, the target total voltage is dropped step by step as time goes.