HEAT PUMP SYSTEM FOR VEHICLE

An embodiment heat pump system for a vehicle includes a compressor for compressing a refrigerant, a condenser connected to the compressor, a heat exchanger connected to the condenser, a first expansion valve connected to the heat exchanger, an evaporator connected to the first expansion valve, a first refrigerant connection line having ends connected between the compressor and the evaporator and between the heat exchanger and the first expansion valve, a chiller and a second expansion valve on the first refrigerant connection line, and a gas injection device for selectively expanding and flowing the refrigerant supplied from the condenser or the heat exchanger and for selectively supplying a portion of the refrigerant to the compressor to increase a flow rate of the refrigerant, wherein the flow of the refrigerant is controlled according to a mode for controlling a temperature of a vehicle interior or a battery module.