Cooling critical layout components
The figure shows common components in the cooling and heating cycle system of pure electric vehicles, such as a.heat exchangers, b.four-way valves, c.electric water pumps and d.PTCs, etc.
Pure electric vehicle schematic diagram analysis
The electric vehicle belongs to the design of 2+2 front and rear dual motors. There are 4 circuits in the cooling and heating cycle, motor circuit, battery circuit, air conditioning cooling circuit and air conditioning heating circuit. The related circuit is shown in Figure 2, and the functions of related system components are shown in Table 2.
Among them, circuit 1 is the most important circuit, which is responsible for cooling the motor, electric control and small three power in the big three power, among which the small three power integrates three functions of OBD, DC\DC, and PDCU. Among them, the motor is oil-cooled, and the cooling water circuit is cooled by the heat exchange of the plate exchanger that comes with the motor. The parts of the front cabin belong to the series structure, and the parts of the rear cabin belong to the series structure. The whole can be designed in parallel, and the three-way valve 1 It can be regarded as a thermostat device. When the motor and other components are at low temperature, the circuit 1 can be regarded as a small circuit without passing through the radiator device. When the temperature of the components rises, the three-way valve is opened, and the circuit 2 passes through the low-temperature radiator. It can be seen as a medium circuit.
Loop 2 is the loop for cooling and heating the battery pack [3]. The battery pack has a built-in water pump, which exchanges heat and cold through the plate exchanger 1, the warm air loop 3 and the condensation loop 4 of the air conditioner. When the ambient temperature is too low , the warm air circuit 3 is turned on, and the battery pack is heated through the plate exchanger 1. When the ambient temperature is too high, the condensation circuit 4 is opened, and the battery pack is cooled through the plate exchanger 1, so that the battery pack is always at a constant temperature State, functionally at its best. In addition, circuit 1 and circuit 2 are connected through a four-way valve. When the four-way valve is not energized, the two circuits 1 and 2 are independent of each other. In the circulating state, the waterway 1 can heat the waterway 2.
Both loop 3 and loop 4 belong to the air conditioning system, of which loop 3 is the heating system, because the electric vehicle does not have the heat source of the engine, it needs to obtain the external heat source, and the loop 3 exchanges the high temperature and high pressure generated by the air conditioning compressor in the loop 4 through the heat exchanger 2 The temperature generated by the gas, and there is a PTC coolant heater/PTC air heater in the circuit 3. When the temperature is too low, it can be heated by electricity to heat the water in the air-conditioning and heating water pipe. The circuit 3 enters the air-conditioning and heating system, and the blower provides heating. When valve 2 is not energized, it can form a small circuit by itself. When energized, circuit 3 heats circuit 1 through heat exchanger 1.
Circuit 4 is the air conditioner cooling pipeline. In addition to heat exchange with circuit 3, this circuit is connected to the front air conditioner, rear air conditioner, and heat exchanger 2 of circuit 2 through the throttle valve. It can be understood as 3 small circuits, throttling The three circuits connected to the valves have electronic control cut-off valves, which electronically control whether the circuits are connected.
Through such a set of cooling and heating cycle system, the battery pack can be charged and discharged normally without affecting the life of the battery pack, and a series of systems such as the motor and the small three electrics can achieve a good cooling effect.
Post time: Mar-23-2023
