Patent ID: 8339104

Claim:
A battery system for a vehicle comprising: a battery set including a plurality of battery cells; a charge/discharge unit, connected to the battery set through electric wires, for performing a ripple charge/discharge operation to alternately charge and discharge the battery set a plurality of times per unit time, thereby to boost a DC voltage of the battery set; an inverter unit, connected to the charge/discharge unit through electric wires, for converting the boosted DC voltage outputted from the charge/discharge unit to an AC voltage thereby to supply a drive voltage to a drive motor, which drives drive wheels of the vehicle; a converter heat exchanger for exchanging heat generated by the charge/discharge unit with heat transfer medium; a transfer unit for transferring the heat transfer medium toward the battery set; and a control unit for controlling the charge/discharge unit, the inverter unit and the transfer unit in accordance with conditions of the battery set, wherein the charge/discharge unit is located closer to the battery set than the inverter unit is, and wherein, when the control unit determines that the battery set is incapable of supplying a predetermined electric power due to a low temperature condition of the battery set, the control unit controls the charge/discharge unit to perform the ripple charge/discharge operation and controls the transfer unit to transfer the heat transfer medium from the converter heat exchanger to the battery set after receiving the heat generated by the charge/discharge unit.