Development History of Electric Vehicle Thermal Management Technology
First stage PTC heating
Vehicle thermal management is one of the core technologies in the development of electric vehicles, involving multi-objective management such as temperature and humidity environment control of the passenger compartment, power system temperature control, and glass anti-fog and demist. According to the thermal management system architecture and integration degree, the development of electric vehicle thermal management is summarized into three stages.
In the initial stage of the industrialization of electric vehicles, the core technology is basically based on the replacement of batteries, motors and other power systems. based on gradual improvements. The air conditioner of pure electric vehicle and the air conditioner of fuel vehicle both realize the refrigeration function through the vapor compression cycle. The difference between the two is that the air conditioner compressor of fuel vehicle is indirectly driven by the engine through the belt, while the pure electric vehicle directly uses the electric drive compressor to drive the refrigeration. cycle. When fuel vehicles are heated in winter, the waste heat of the engine is directly used to heat the passenger compartment without an additional heat source. However, the waste heat of the motor of pure electric vehicles cannot meet the needs of winter heating. Therefore, winter heating is a problem that pure electric vehicles need to solve. . Positive temperature coefficient heaters (positive temperature coefficient, PTC) are composed of PTC ceramic heating elements and aluminum tubes, which have the advantages of small thermal resistance and high heat transfer efficiency, and are less modified on the basis of fuel vehicles. Therefore, early electric vehicles Vehicles use vapor compression refrigeration cycle refrigeration plus PTC heating to achieve thermal management of the passenger compartment. Unlike gasoline vehicles, which are powered by fuel, electric vehicles are powered by power batteries. When the electric vehicle is running normally, the power battery discharges heat and the temperature rises, so the battery needs to be cooled. The battery cooling methods mainly include air cooling, liquid cooling, phase change material cooling, and heat pipe cooling. Air cooling has been widely used in early electric vehicles due to its simple structure, low cost, and easy maintenance. The main form of thermal management at this stage is that each independent subsystem meets the requirements of thermal management respectively.
