Patent ID: 7683570
Filing Date: 2010-03-23
Classification: B60L,H01M,Y02E,Y02T

Abstract:
1. An apparatus comprising: a rechargeable battery pack installed in an electric vehicle, the rechargeable battery pack coupled to a power supply, the power supply operable to provide a charge voltage to perform charging operations on the rechargeable battery pack; a heating element to heat a fluid to be circulated through the rechargeable battery pack, the fluid thermally coupled to battery cells within the rechargeable battery pack; a comparator circuit to compare a battery voltage of the rechargeable battery pack to a line source voltage coupled to inputs of the power supply, the comparator circuit operable to compare the battery voltage to the line source voltage and to provide an output signal when the battery voltage is less than a line voltage offset value, the line voltage offset value calculated based on a value added to a determined voltage level for the line source voltage; and a control circuit coupled to receive the output signal of the comparator, and when a charge operation of the rechargeable battery pack is to be initiated, the control circuit is operable to couple the line source voltage to the power supply, wherein the control circuit is to couple the heating element in series between the line source voltage and the power supply when the comparator circuit is providing the output signal indicating that the battery voltage is less than the line voltage offset value, and to bypass the heating element if the comparator is not providing the output signal indicating that the battery voltage is less than the line voltage offset value.