VEHICLE POWER SUPPLY DEVICE AND ITS DEGRADATION JUDGMENT METHOD

摘要

A vehicle power supply device includes a capacitor unit having a plurality of capacitors for accumulating auxiliary power, a temperature sensor, a charge circuit, a capacitor unit current detection unit, a capacitor unit voltage detection unit, a control unit, a storage unit, and a judgment unit. The storage unit contains: a correction calculation expression used for obtaining an internal resistance correction calculation value and a capacity correction calculation value by performing correction calculation of the internal resistance value and the capacity value according to the obtained temperature; and degradation judgment expressions used for calculating the internal resistance judgment reference value from the capacity correction calculation value and arranged corresponding to a numerical value range of the capacity correction calculation value. The judgment unit judges the degradation state of the capacitor unit at least according to the internal resistance judgment reference value or the capacity correction calculation value. With this configuration, it is possible to provide a vehicle power supply device capable of accurately performing degradation judgment so that the vehicle power supply device is used up to the end of its service life.