Vehicle power supply device

A vehicle power supply device that supplies electric power to a plurality of auxiliary loads that is installed in a vehicle, the vehicle power supply device comprising:

• a power supply source;
• an auxiliary battery, including a lithium-ion battery that is chargeable by the power supply source;
• a direct current (DC)-DC converter that is provided between the power supply source and the auxiliary loads, and that controls electric power supply from the power supply source to the auxiliary loads;
• a switch that is provided between the DC-DC converter and the auxiliary loads, and the auxiliary battery, and that switches an electrical connection state between the auxiliary loads and the auxiliary battery;
• and
• a control unit that controls the DC-DC converter and the switch, wherein the control unit controls output voltage of the DC-DC converter such that a second voltage when the switch is interrupted is higher than a first voltage when the switch is conducting,
• wherein, when receiving a request from at least one of the auxiliary loads to raise the output voltage of the DC-DC converter, in a case in which the auxiliary battery is in a state of being charged, the control unit temporarily limits electric power consumed by the auxiliary loads, then interrupts the switch, and following interrupting the switch, raises the output voltage of the DC-DC converter from the first voltage to the second voltage.