In new energy vehicles, the currently widely used thermal management system is the mode of "electric compressor refrigeration + electric heater (PTC) heating". The system has a simple structure and is relatively easy to realize, and can be directly modified on the original fuel vehicle air conditioning system.
In the passenger compartment refrigeration scheme, it can be realized by replacing the mechanical compressor of the original fuel vehicle air conditioning system with an electric compressor. In the passenger compartment heating scheme, traditional fuel vehicles and PHEVs can use the residual heat of engine cooling water to heat the passenger compartment, and the heating effect is relatively sufficient, and no additional fuel consumption is basically generated; in pure electric vehicles, since there is no engine to provide hot water , so the heating scheme needs a completely different design: a relatively simple scheme is to use an electric heater for heating, for example: using an air side heater (APTC) instead of the heater core in the HVAC to directly heat the air; or using a water side heater (WPTC), heat the water circuit to form a heat source similar to the engine cooling water, and then send the hot water to the heater core to heat the air.
For the thermal management of the battery, the refrigeration circuit of the air conditioning system of the passenger cabin is usually introduced into the battery cooler, the cooling water circuit, and the cooling water is sent to the battery pack to cool the battery; when heating, an electric heater is used to directly heat the battery，air or water to heat the battery. When using a water heater, it is possible to share a heating circuit with the air conditioning system.
The electric heater is used to heat the passenger compartment and the battery pack. The structure is simple and the control strategy is relatively simple. Single, low cost, mature technology. However, the energy efficiency ratio of the electric heater (heating amount/electric power input) is in the range of 0.85-0.95, and the energy efficiency is relatively low. When the electric heater is used for heating in winter, the battery energy is rapidly consumed, which seriously affects the electricity consumption. Motor vehicle driving range.
