Patent ID: 7680612
Filing Date: 2010-03-16
Classification: B60L,B60R,B60T,G01R,Y02T

Abstract:
1. A vehicle power supply device comprising: a capacitor unit including a plurality of capacitors storing auxiliary power; a temperature sensor detecting a temperature of the capacitor unit; a charge circuit charging the capacitor unit; a capacitor-unit current detector detecting a current of the capacitor unit; a capacitor-unit voltage detector detecting a voltage of the capacitor unit; a switch being switched so as to make the capacitor unit output the auxiliary power when necessary; and a controller electrically connected to the temperature sensor, the charge circuit, the capacitor-unit current detector, the capacitor-unit voltage detector, and the switch, wherein the controller suspends and resumes a constant current charging or discharging or the capacitor unit so as to make the capacitor-unit voltage detector detect a change in a charge or discharge voltage of the capacitor unit before and after the constant current charging or discharging is resumed, thereby calculating an internal resistance value of the capacitor unit from the change detected by the capacitor-unit voltage detector and from an output of the capacitor-unit current detector; the controller then calculates a capacitance value of the capacitor unit from a voltage change rate of the capacitor unit during charge or discharge and from the output of the capacitor-unit current detector; and the controller then calculates a standard value from the capacitance value using a degradation determination formula according to the temperature detected by the temperature sensor, and determines that the capacitor unit is degraded when the standard value is not more than the internal resistance value.