Heat Pump System for Vehicle

An embodiment heat pump system for a vehicle includes a cooling apparatus including a radiator and a multi-way valve connected by a first coolant line and configured to circulate a coolant in the first coolant line, a second coolant line including first and second ends connected to the multi-way valve and equipped with a first water pump and an electrical component, a third coolant line including first and second ends connected to the multi-way valve and equipped with a second water pump and a battery module, a chiller provided on the third coolant line, connected to a refrigerant line of an air conditioner device through a refrigerant connection line, and configured to adjust a temperature of the coolant circulated in the third coolant line, and a gas injection device configured to selectively expand a refrigerant and to selectively supply some of the refrigerant to a compressor.