System for and method of extinguishing fire occurring in high-voltage battery for vehicle

A system for extinguishing a fire occurring in a high-voltage battery for a vehicle, the system comprising:

• a battery cell assembly in which a plurality of battery cells are stacked each other:
• an extinguishing-liquid tank inside which an extinguishing liquid is stored:
• an extinguishing-liquid supply line connecting the extinguishing-liquid tank and the inside of the battery cell assembly to each other:
• a coolant joining line branching off from a coolant line through which a coolant circulates along the outside of the battery cell assembly and a radiator and connected to the extinguishing-liquid supply line, the coolant being supplied to the inside of the battery cell assembly through the coolant joining line;
• and
• a control unit configured to perform control so that the extinguishing liquid and the coolant are supplied to the inside of the battery cell assembly through the extinguishing-liquid supply line and the coolant joining line, when the control unit concludes that the fire occurs in the battery cell assembly.