COOLANT CIRCULATION SYSTEM OF VEHICLE

In a coolant circulation system of a vehicle, a connecting unit is connected to a coolant line of a vehicle circulating through a battery of the vehicle. When connected to the coolant line, the connecting unit allows coolant to be discharged from the vehicle or be introduced into the coolant line. A supply unit includes a cooling tank in which the coolant is stored or circulates and a heating tank. The cooling tank includes an evaporation core, and the heating tank includes a condensing core. The evaporation core and the condensing core are connected to the coolant line on which a compressor, an expansion valve, and an external condenser are provided. When the connecting unit is connected to the coolant line, the supply unit is configured to supply the coolant from the cooling tank or the heating tank to the coolant line of the vehicle, cooling or heating the battery.