Battery Cooling System in EV
Car air conditioning consists of a refrigeration system and a heating system. The function of the refrigeration system is to reduce the temperature inside the vehicle by absorbing heat when the refrigerant evaporates. The function of the heating system is to send cold air into the heater core for heating, and to send hot air into the cabin for heating.
(1) Refrigeration system composition
The refrigeration system is mainly composed of air conditioning compressor, condenser, evaporator, expansion valve, liquid storage drying tank, cooling fan, blower motor and control unit.
(2) Working principle of refrigeration system
The air-conditioning compressor of electric vehicles is an electric compressor, driven by high-voltage electricity to rotate (its speed can be actively adjusted by the air-conditioning system, and its adjustment range is 0~4000r/min). The high-temperature and high-pressure refrigerant vapor discharged by the compressor passes through The high-pressure hose enters the condenser of the air conditioner. Since the temperature of the high-temperature and high-pressure refrigerant vapor is higher than the temperature of the air outside the car, the heat of the refrigerant vapor in the condenser is taken away by the air outside the car with the help of the condenser fan, so that the high-temperature and high-pressure refrigerant vapor condenses into higher temperature High pressure liquid.
It flows into the drying reservoir through the high-pressure hose. After drying and filtering, it flows through the expansion valve. Under the throttling effect of the expansion valve, the refrigerant turns into a low-temperature and low-pressure liquid and enters the evaporator of the car air conditioner, where it vaporizes under constant pressure. It also absorbs the heat in the air outside the evaporator tube, so that the temperature of the air circulating in the car that flows through the evaporator is reduced to cold air, which is sent into the car through the blower to reduce the temperature of the air in the car.
The vaporized refrigerant vapor is sucked in and compressed by the compressor, and turns into high-temperature and high-pressure refrigerant gas. It is pressed into the condenser of the automobile air conditioner through the high-pressure hose to complete a refrigeration cycle of the automobile air conditioner.
The refrigeration system achieves refrigeration through the heat absorption and heat release processes caused by the gas-liquid two-phase conversion of the refrigerant. Centering around the gas-liquid conversion of refrigerant, the refrigeration working cycle can be summarized into four processes: compression, heat release, throttling and heat absorption.