New Energy Vehicle Air Conditioning Heater PTC Technology and Market
Compared with the traditional automobile thermal management system, the difference between the new energy vehicle thermal management system is that the management object extends from the cockpit to the battery, motor electronic control and other fields, and the second is that its function extends from simple cooling to insulation and heating functions. . Therefore, compared with traditional vehicles, the thermal management system of new energy vehicles has added electronic water pumps, electric compressors, electronic expansion valves or four-way valves, cooling plates and heating systems (heat pumps or PTC systems).
New energy vehicle air conditioning system solution
The heating source of the air conditioning system of a fuel vehicle is mainly provided by the engine coolant, but the heating system of an electric vehicle is different from this. Common solutions for heating air in electric vehicle air conditioning systems are as follows:
①Heat pump. The working principle of the electric vehicle heat pump air conditioning system driven by a transmission belt driven by a brushless DC motor is shown in the figure. The cooling/heating mode of the air conditioning system is switched by the four-way reversing valve. The solid arrow indicates the cooling condition and the dotted arrow indicates the heating condition. In principle, this system is no different from an ordinary heat pump air conditioner, but for use in electric vehicles, it has specially developed a dual working chamber sliding vane compressor, DC brushless motor and inverter control system. Under heat pump operating conditions, when the system switches from defrost mode to heating mode, the condensed water on the heat exchanger in the air duct will quickly evaporate and frost will form on the windshield, affecting driving safety.
②PTC electric heater. PTC electric heater is a heater that uses PTC thermistor element as the heat source. PTC thermistors are usually made of semiconductor materials, and their resistance changes sharply with changes in humidity. When the outside temperature decreases, the PTC resistance value decreases, and the heat generation increases accordingly. According to the material, it can be divided into ceramic PTC thermistor and organic polymer PTC thermistor. Ceramic PTC thermistors are used in air conditioning auxiliary electric heaters. Because the PTC thermistor element has the changing characteristics of increasing or decreasing its resistance value as the ambient temperature changes, the PTC heater has the characteristics of energy saving, constant temperature, safety and long service life.
PTC heaters include PT air heaters and PTC liquid heaters. Since the PTC liquid heater can be placed in the cabin, it can be directly used in the air-conditioning system of existing cars and is more widely used in electric vehicle heating systems.
