CN111251826A - Passenger cabin priority refrigeration control method for pure electric vehicle thermal management system - Google Patents

Abstract

The invention discloses a passenger compartment priority refrigeration control method of a pure electric vehicle thermal management system, which is characterized by comprising the following steps of: the method comprises the steps of 1) entering a simultaneous refrigeration mode, and starting an electric refrigeration system and a battery cooling water loop; 2) entering a passenger compartment priority refrigeration mode, and closing a battery cooling water loop; 3) keeping entering a passenger compartment priority refrigeration mode; 4) exiting the simultaneous cooling mode and restarting the battery cooling water loop; 5) keeping exiting the simultaneous cooling mode; 6) and repeatedly circulating the step 2) and the step 4) until the simultaneous cooling mode is exited. On the premise of ensuring the safety of the power battery, the refrigeration requirement of the passenger compartment is preferentially ensured; the system is switched frequently, thereby ensuring the stability of the system operation.

Description

Priority refrigeration control method for passenger compartment of pure electric vehicle thermal management system

technical field

The invention relates to the technical field of automobile thermal management, in particular to a method for preferential refrigeration control of a passenger compartment of a thermal management system of a pure electric vehicle.

Background technique

As countries around the world pay more and more attention to environmental and energy issues, pure electric vehicles have been widely favored by all walks of life. However, the development of pure electric vehicles is still in its infancy, and there are many key problems to be solved. Management system technology maturity constraints. An excellent vehicle thermal management system has a very significant contribution to reducing battery energy consumption, increasing cruising range, and improving vehicle reliability and comfort.

In the existing thermal management system of pure electric vehicle, the battery circuit and the air conditioning circuit share the refrigerant. Because the performance of the power battery has a great relationship with the temperature, high temperature will increase the risk of thermal runaway and safety risk. In order to reduce the safety risk, the cooling capacity of the whole vehicle is fully allocated to the battery refrigeration circuit to reduce the battery temperature. When the battery temperature reaches a safe range, It will start to meet the needs of the passenger compartment, thus reducing the cooling effect of the passenger compartment, resulting in a slow cooling speed of the passenger compartment, which seriously affects the comfort of the whole vehicle.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the above-mentioned deficiencies in the prior art, and to provide a method for controlling the priority refrigeration of the passenger compartment of a thermal management system of a pure electric vehicle. , Priority is given to ensuring the cooling demand of the passenger compartment, and it can stably switch between the simultaneous cooling mode and the priority cooling mode of the passenger compartment.

In order to achieve the above object, the present invention provides a method for controlling the priority refrigeration of the passenger compartment of a thermal management system of a pure electric vehicle, which is characterized in that:

The pure electric vehicle thermal management system includes an electric refrigeration system and a battery cooling water circuit. The electric refrigeration system includes a parallel cold coal branch for cooling the battery and a cold coal branch for cooling the passenger compartment. The branch circuit exchanges heat with the battery cooling water circuit through the battery cooler, and the heat exchange of the battery cooling water circuit includes the power battery;

The priority refrigeration control method for the passenger compartment includes the following steps:

1) Enter the simultaneous cooling mode, turn on the electric cooling system and the battery cooling water circuit;

2) When the maximum temperature of the power battery is less than or equal to the critical lower limit value T ₁ of the maximum temperature of the power battery, and the average temperature of the power battery is less than or equal to the critical lower limit value T ₂ of the average temperature of the power battery, and the passenger compartment returns When the air temperature is greater than or equal to the critical upper limit value T ₃ of the return air temperature of the passenger compartment, close the battery cooling water circuit and the cooling coal branch for cooling the battery;

4) When the maximum temperature of the power battery is greater than or equal to the critical upper limit value T ₅ of the maximum temperature of the power battery, or the average temperature of the power battery is greater than or equal to the critical upper limit value T ₆ of the average temperature of the power battery, or the passenger compartment returns When the air temperature is less than or equal to the critical lower limit value T ₇ of the return air temperature of the passenger compartment, reopen the battery cooling water circuit and the cooling coal branch for cooling the battery;

6) Repeat the above steps 2) and 4) until the simultaneous cooling mode is exited.

Further, between step 2) and step 4), it also includes step 3): when the maximum temperature of the power battery is greater than T ₁ and less than T ₅ , or the average temperature of the power battery is greater than T ₂ and less than T _6. When the return air temperature of the passenger compartment is greater _than T3 and less than _T7 , keep closing the battery cooling water circuit and the cooling coal branch for cooling the battery; between step 4) and step 6), also include step 5): when When the maximum temperature of the power battery is greater than T1 and less than _T5 , or the average temperature of the power battery is greater _than T2 and less _{than T6} , or the return air temperature of the passenger compartment is greater _than T3 and less than _T7 , keep the battery cooling turned on Water circuit and cold coal branch to cool the battery.

Further, in step 3), the conditions for re-opening the battery cooling water circuit and the cooling coal branch for cooling the battery further include: and the priority refrigeration time of the passenger compartment is greater than or equal to the critical value of the priority refrigeration time of the passenger compartment.

Further, the critical value of the priority cooling time of the passenger compartment is positively correlated with the ambient temperature.

Further, the electric refrigeration system includes a compressor and a condenser connected in series, and both ends of the parallel cold coal branch for cooling the battery and the cold coal branch for cooling the passenger compartment are connected to the compressor and the condenser, respectively. .

Further, the cold coal branch for cooling the battery includes a battery cooling expansion valve and a battery cooler connected in series; the cold coal branch for cooling the passenger compartment includes a passenger compartment refrigeration expansion valve and an evaporator connected in series. The cold coal branch for cooling the passenger compartment exchanges heat with the passenger compartment cooling air branch through the evaporator, and a temperature sensor is provided at the air return end of the passenger compartment cooling air branch.

Further, the battery cooling water circuit includes a power battery, a water pump, and a battery cooler connected in series, and a temperature sensor is provided at the cooling water outlet of the power battery and the battery cooler.

Further, the pure electric vehicle thermal management system further includes a thermal management controller and a passenger compartment priority refrigeration timer, and the signal input ends of the thermal management controller are respectively connected in communication with the temperature sensor and the passenger compartment priority refrigeration timer; The signal output ends of the thermal management controller are respectively connected in communication with the water pump, the battery cooler, the battery cooling expansion valve, the passenger compartment refrigeration expansion valve and the compressor.

The beneficial effects of the present invention are as follows:

1. Priority is given to ensuring the cooling demand of the passenger compartment. The present invention determines whether the power battery is in a safe range and the cooling demand of the passenger compartment by the maximum temperature of the power battery, the average temperature of the power battery and the return air temperature of the passenger compartment. cooling needs.

2. The switching stability between the cooling mode and the priority cooling mode of the passenger compartment is high. When switching between the simultaneous cooling mode and the priority cooling mode of the passenger compartment, the maximum temperature of the power battery, the average temperature of the power battery and the critical value of the return air temperature of the passenger compartment are not set to a fixed value, but an interval, which avoids the need for When each parameter frequently jumps up and down a single critical value, the system switches frequently, thus ensuring the stability of the system operation.

Description of drawings

FIG. 1 is a schematic structural diagram of the thermal management system of the passenger compartment and the power battery.

The components in the figure are labeled as follows: thermal management controller 1, power battery 2, water pump 3, battery cooler 4, battery cooling expansion valve 5, passenger compartment refrigeration expansion valve 6, evaporator 7, compressor 8, condenser 9, The passenger compartment 11 , the passenger compartment circulation fan 12 , the temperature sensor 13 , and the passenger compartment priority refrigeration timer 14 .

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings to facilitate a clearer understanding of the present invention, but they do not constitute a limitation of the present invention.

As shown in Figure 1, a pure electric vehicle thermal management system includes an electric refrigeration system and a battery cooling water circuit. The electric refrigeration system includes a series-connected compressor 8, a condenser 9 and a cold coal branch for cooling the passenger compartment. The cold coal branch of the cabin is connected in parallel with the cold coal branch for cooling the battery, and the cold coal branch for cooling the battery exchanges heat with the battery cooling water circuit through the battery cooler 4; the cold coal branch for cooling the passenger cabin communicates with the passengers through the evaporator 7 The cabin cooling air branch exchanges heat. In this way, the entire system cools both the power battery and the passenger compartment.

In the above technical solution, the cold coal branch for cooling the battery includes the battery cooling expansion valve 5 and the battery cooler 4 connected in series; the battery cooling water circuit includes the power battery 2, the water pump 3 and the battery cooler 4 connected in series, the power battery 2 and the battery The cooling water outlets of the cooler 4 are all provided with temperature sensors 13 , and the power battery 2 is uniformly provided with a plurality of temperature sensors 13 . In this way, the refrigerant absorbs heat to heat up in the battery cooler, and the cooling water releases heat to cool down in the battery cooler.

The cold coal branch for cooling the passenger compartment includes the passenger compartment refrigeration expansion valve 6 and the evaporator 7 in series, and the passenger compartment cooling air branch includes the series connected evaporator 7, the passenger compartment 11 and the passenger compartment circulating fan 12, and the return of the evaporator 7. The wind end is provided with a temperature sensor 13 . In this way, the air in the passenger compartment is radiated and cooled in the evaporator 7, and the refrigerant is heated up by absorbing heat in the evaporator. In this way, whether in the simultaneous cooling mode of the passenger compartment and the power battery or in the priority cooling mode of the passenger compartment, the passenger compartment refrigeration expansion valve and the passenger compartment circulation fan are always on.

In the above technical solution, the pure electric vehicle thermal management system further includes a thermal management controller 1 and a passenger compartment priority refrigeration timer 14, and the signal input end of the thermal management controller 1 communicates with the temperature sensor 13 and the passenger compartment priority refrigeration timer 14 respectively. Connection; the signal output end of the thermal management controller 1 is respectively connected to the water pump 2, the battery cooler 4, the battery cooling expansion valve 5, the passenger compartment refrigeration expansion valve 6, the compressor 8 and the passenger compartment circulating fan 12. In this way, the thermal management controller determines which cooling mode the system is in by using each temperature sensor and the value of the priority cooling timer of the passenger compartment, and realizes switching between different cooling modes through the above-mentioned actuator.

A priority refrigeration control method for a passenger compartment based on the above-mentioned pure electric vehicle thermal management system, comprising the following steps:

1) When the occupant in the car turns on the electric cooling button, and the temperature of the power battery exceeds the safe range, the system enters the simultaneous cooling mode of the passenger compartment and the power battery, and the thermal management controller 1 controls the water pump 2, the battery cooler 4, and the battery cooling expansion valve 5. , The passenger compartment refrigeration expansion valve 6, the compressor 8 and the passenger compartment circulating fan 12 are turned on, the electric refrigeration system and the battery cooling water circuit are turned on, and the cold coal branch for cooling the passenger compartment and the cold coal branch for cooling the battery are both turned on. The maximum temperature of the power battery 2 and the average temperature of the power battery 2 gradually decrease.

2) When the maximum temperature of the power battery 2 is less than or equal to the critical lower limit value T ₁ of the maximum temperature of the power battery, and the average temperature of the power battery 2 is less than or equal to the critical lower limit value T ₂ of the average temperature of the power battery, and the return air temperature of the passenger compartment Greater than or equal to the passenger compartment return air temperature critical upper limit value T ₃ , the battery cooler closing temperature T ₄ , the thermal management controller 1 controls the water pump 2, the battery cooler 4 and the battery cooling expansion valve 5 to close, close the battery cooling water circuit and The cold coal branch of the cooling battery makes the system in the passenger compartment priority cooling mode, and the maximum temperature of the power battery 2 and the average temperature of the power battery 2 both begin to increase.

3) When the maximum temperature of the power battery 2 is greater than the critical lower limit value T ₁ of the maximum temperature of the power battery and less than the critical upper limit value T ₅ of the maximum temperature of the power battery, or the average temperature of the power battery 2 is greater than the critical lower limit value T of the average temperature of the power battery ₂ and is less than the critical upper limit value T ₆ of the average temperature of the power battery, or the return air temperature of the passenger compartment is greater than the critical upper limit value T ₃ of the return air temperature of the passenger compartment and less than the critical lower limit value T ₇ of the return air temperature of the passenger compartment, the system is still in the The passenger compartment is given priority to the cooling mode, the battery cooling water circuit and the cold coal branch for cooling the battery are kept closed, and the maximum temperature of the power battery 2 and the average temperature of the power battery 2 are further increased.

4) When the maximum temperature of the power battery 2 is greater than or equal to the critical upper limit value T ₅ of the maximum temperature of the power battery, or the average temperature of the power battery 2 is greater than or equal to the critical upper limit value T ₆ of the average temperature of the power battery, or the return air temperature of the passenger compartment If it is less than or equal to the critical lower limit value T ₇ of the return air temperature of the passenger compartment, the system exits the priority cooling mode of the passenger compartment, reopens the battery cooling water circuit and the cold coal branch for cooling the battery, the maximum temperature of the power battery 2 and the average value of the power battery 2 The temperature starts to drop.

₅ ) When the maximum temperature of the power battery 2 is greater than T1 and less than the critical upper limit value T5 of the maximum temperature of the power battery, or the average temperature of the power battery 2 is greater than T2 and less than T6, or when the return air temperature of the passenger compartment is greater than T3 and less than T7, Keeping the battery cooling water circuit and the cooling coal branch for cooling the battery open, the maximum temperature of the power battery 2 and the average temperature of the power battery 2 are further reduced.

6) Repeat the above steps 2) and 4) until the occupant chooses to exit the simultaneous cooling mode.

In step 3) of the above control method, the conditions for re-opening the battery cooling water circuit and the cooling coal branch for cooling the battery further include: and the priority refrigeration time of the passenger compartment is greater than or equal to the critical value of the priority refrigeration time of the passenger compartment. The critical value of the priority cooling time of the passenger compartment is positively correlated with the ambient temperature. In this way, the system is prevented from being in the priority cooling mode of the passenger compartment for a long time, and the condition of re-entering the simultaneous cooling mode of the passenger compartment and the power battery is prevented, and the temperature of the power battery is preferentially protected in a safe area.

The above-mentioned passenger cabin priority refrigeration control method based on the pure electric vehicle thermal management system determines whether the power battery is in the safe range and the cooling demand of the passenger cabin by the maximum temperature of the power battery, the average temperature of the power battery and the return air temperature of the passenger cabin. On the premise of the safety of the power battery, the cooling demand of the passenger compartment is given priority.

Secondly, when switching between the simultaneous cooling mode and the priority cooling mode of the passenger compartment, the maximum temperature of the power battery, the average temperature of the power battery and the critical value of the return air temperature of the passenger compartment are not set to a fixed value, but an interval, so as to avoid When each parameter frequently jumps up and down a single critical value, the system switches frequently, thus ensuring the stability of the system operation.

Claims (8)

1. A passenger cabin priority refrigeration control method of a pure electric vehicle thermal management system is characterized by comprising the following steps:

the pure electric vehicle heat management system comprises an electric refrigeration system and a battery cooling water loop, wherein the electric refrigeration system comprises a cold coal branch for cooling a battery and a cold coal branch for cooling a passenger cabin which are connected in parallel, the cold coal branch for cooling the battery exchanges heat with the battery cooling water loop through a battery cooler (4), and the battery cooling water loop exchanges heat and comprises a power battery (2);

the passenger compartment priority refrigeration control method comprises the following steps:

1) entering a simultaneous refrigeration mode, and starting an electric refrigeration system and a battery cooling water loop;

2) when the highest temperature of the power battery (2) is less than or equal to the critical lower limit value T of the highest temperature of the power battery₁And the average temperature of the power battery (2) is less than or equal to the critical lower limit value T of the average temperature of the power battery₂And the return air temperature of the passenger compartment is greater than or equal to the critical upper limit value T of the return air temperature of the passenger compartment₃Closing a battery cooling water loop and a cold coal branch for cooling the battery;

4) when the highest temperature of the power battery (2) is greater than or equal to the critical upper limit value T of the highest temperature of the power battery₅Or the average temperature of the power battery (2) is greater than or equal to the critical upper limit value T of the average temperature of the power battery₆Or the return air temperature of the passenger compartment is less than or equal to the critical lower limit value T of the return air temperature of the passenger compartment₇The battery cooling water loop and the cold coal branch for cooling the battery are restarted;

6) and repeating the step 2) and the step 4) until the simultaneous cooling mode is exited.

2. The passenger compartment priority refrigeration control method of the pure electric vehicle thermal management system according to claim 1, characterized by comprising the following steps: between step 2) and step 4), further comprising step 3): when the maximum temperature of the power battery (2) is more than T₁And is less than T₅Or the average temperature of the power battery (2) is more than T₂And is less than T₆Or the return air temperature of the passenger compartment is more than T₃And is less than T₇When the battery is in use, the battery cooling water loop and the cold coal branch for cooling the battery are kept closed; between the step 4) and the step 6), the method further comprises the step 5): when the maximum temperature of the power battery (2) is more than T₁And is less than T₅Or the average temperature of the power battery (2) is more than T₂And is less than T₆Or the return air temperature of the passenger compartment is more than T₃And is less than T₇And keeping opening the battery cooling water loop and the cold coal branch for cooling the battery.

3. The passenger compartment priority refrigeration control method of the pure electric vehicle thermal management system according to claim 2, characterized in that: in step 3), the conditions for restarting the battery cooling water loop and cooling the coal cooling branch of the battery further include: and the passenger compartment priority refrigeration time is greater than or equal to the passenger compartment priority refrigeration time critical value.

4. The passenger compartment priority refrigeration control method of the pure electric vehicle thermal management system according to claim 3, characterized in that: the passenger compartment priority refrigeration time critical value is positively correlated with the ambient temperature.

5. The passenger compartment priority refrigeration control method of the pure electric vehicle thermal management system according to claim 4, characterized in that: the electric refrigeration system comprises a compressor (8) and a condenser (9) which are connected in series, and two ends of a cold coal branch of the cooling battery and two ends of a cold coal branch of the cooling passenger cabin which are connected in parallel are respectively connected with the compressor (8) and the condenser (9).

6. The passenger compartment priority refrigeration control method of the pure electric vehicle thermal management system according to claim 5, characterized in that: the cold coal branch of the cooling battery comprises a battery cooling expansion valve (5) and a battery cooler (4) which are connected in series; the cold coal branch for cooling the passenger compartment comprises a passenger compartment refrigeration expansion valve (6) and an evaporator (7) which are connected in series, the cold coal branch for cooling the passenger compartment exchanges heat with a passenger compartment cooling air branch through the evaporator (7), and a temperature sensor (13) is arranged at the air return end of the passenger compartment cooling air branch.

7. The passenger compartment priority refrigeration control method of the pure electric vehicle thermal management system according to claim 6, characterized in that: the battery cooling water loop comprises a power battery (2), a water pump (3) and a battery cooler (4) which are connected in series, and cooling water outlets of the power battery (2) and the battery cooler (4) are respectively provided with a temperature sensor (13).

8. The passenger compartment priority refrigeration control method of the pure electric vehicle thermal management system according to claim 7, characterized in that: the pure electric vehicle thermal management system further comprises a thermal management controller (1) and a passenger compartment priority refrigeration timer (14), wherein a signal input end of the thermal management controller (1) is respectively in communication connection with the temperature sensor (13) and the passenger compartment priority refrigeration timer (14); and the signal output end of the thermal management controller (1) is respectively in communication connection with the water pump (2), the battery cooler (4), the battery cooling expansion valve (5), the passenger compartment refrigeration expansion valve (6) and the compressor (8).

Images