VEHICLE POWER SOURCE SYSTEM AND COOLING CIRCUIT

A vehicle power source system includes: a high-voltage battery; a high-voltage system equipment having a DC-DC converter and a charger; and a cooling circuit having a high-voltage battery cooling unit for cooling the high-voltage battery, a DC-DC converter cooling unit for cooling the DC-DC converter, and charger cooling unit for cooling the charger. In the cooling circuit, the DC-DC converter cooling unit and the charger cooling unit are disposed in parallel on a downstream side of the high-voltage battery cooling unit.