Patent ID: 9705319
Date: 2017-07-11
CPC Classifications: B60R,H01M,H02J,Y02E

Claim:
1. A power supply system, comprising: a first storage battery; a battery unit which includes a second storage battery; a generator which charges the first storage battery and the second storage battery, wherein the battery unit is connected to the generator and the first storage battery via a connecting conductor, the battery unit comprising: a fault determining unit which determines a fault of the connecting conductor on the basis of opened and closed states of the first and second switches controlled by the switch control unit and detection results of the first voltage detecting unit and the second voltage detecting unit, wherein the fault determining unit determines that a disconnection fault has occurred in the connecting conductor, when the switch control unit controls both the first switch and the second switch so as to be in closed states and if the voltage of the connection terminal detected by the first voltage detecting unit differs from the electromotive force of the first storage battery detected by the second voltage detecting unit, and the fault determining unit determines that a ground fault has occurred in the connecting conductor, when the switch control unit controls the first switch so as to be in an opened state and the second switch so as to be in a closed state and if the voltage of the connection terminal detected by the first voltage detecting unit is a ground potential; and an electronic control unit (ECU) that receives a fault diagnosis request from a testing equipment, and in response, commands the switch control unit to open and close the first switch and the second switch in order that the fault determining unit is able to determine if the disconnection fault or the ground fault has occurred in the connecting conductor, and outputs to the switch control unit a command for forcibly closing the third switch, wherein the power supply system further comprises a key switch operable by a user for controlling operation of a vehicle power supply and a power supply for an in-vehicle accessory device of a vehicle, the vehicle connected to the battery unit, wherein the key switch has a main switch for turning on and off the vehicle power supply and a sub-switch for turning on and off the power supply for the in-vehicle accessory device, the main switch being capable of being turned on and off only when the sub-switch is turned on, and the main switch and the sub-switch being applied to the vehicle connected to the battery unit, the battery unit has an electrical power supply control unit which controls supplying electrical power from the second storage battery to electric loads on the basis of input signals received from the main switch and the sub-switch; and a second fault determining unit which determines a fault of the key switch on the basis of the input signals received from the main switch and the sub-switch, wherein if the second fault determining unit determines that the fault of the key switch has occurred, the electronic control unit outputs to the switch control unit a command for forcibly closing the third switch.