A hybrid cooling method suitable for electric vehicle thermal management system

Abstract

The present invention provides a hybrid cooling method suitable for an electric vehicle thermal management system, comprising: step S1, judging whether a start command inputted from the outside is received: if so, controlling to start a water-cooled heat exchange device, and then turning to step S2; if not, returning to step S1; step S2, real-time detection of a real-time temperature of antifreeze in the heat exchanger; step S3, judging whether the real-time temperature is greater than a preset temperature: if so, controlling to close a compressed air transmission device and starting a cooling water transmission device, so that the cooling water transmission device outputs cooling water to the cavity for heat exchange with the antifreeze for the first step of cooling, and then turning to step S4; if not, returning to step S2; step S4, controlling a plate heat exchanger to perform a second step of cooling on the antifreeze outputted by the heat exchanger. The beneficial effect is that the present invention adopts a hybrid cooling mode of direct cooling of the cooling heat exchange device and indirect cooling of the plate heat exchanger, which can significantly reduce power consumption and increase safety.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal management systems for electric vehicles, and in particular to a hybrid cooling method suitable for thermal management systems for electric vehicles. Background Art

[0002] In the thermal management system of electric vehicles, the battery pack heater is an indispensable and important component that needs to undergo very harsh test conditions. Therefore, it needs to have good heat dissipation and cooling performance. The cooling method used in the thermal management system of electric vehicles in the existing technology controls the flow of antifreeze according to the flow rate required by the standard through a circulating water pump system. It uses a series connection to flow through the tested sample "battery pack heater", the plate heat exchanger of the compressor refrigeration system, and the heating device. The target temperature of the antifreeze is controlled by mutual compensation and peak shifting of cooling and heating.

[0003] However, the above cooling method only relies on the plate heat exchanger for antifreeze heat exchange. When the sample "battery pack heater" under test is tested, it will generate a lot of heat. Relying solely on the plate heat exchanger will cause the compressor refrigeration system to consume huge electricity, which will cause the plate heat exchanger to work under high load all the time, and the failure rate will be greatly increased. Once the plate heat exchanger fails, the heat dissipation and cooling performance of the entire electric vehicle thermal management system will be greatly reduced, and the power consumption of the electric vehicle thermal management system will be greatly increased. Therefore, cooling the antifreeze through a single plate heat exchanger can no longer meet the heat dissipation requirements of the tested product "battery pack heater" and there will be certain safety hazards. Summary of the invention

[0004] The problem to be solved by the present invention is to provide a hybrid cooling method suitable for a thermal management system of an electric vehicle which meets the heat dissipation requirements of a tested product and has high safety.

[0005] In order to solve the above problems, the present invention provides a hybrid cooling method suitable for an electric vehicle thermal management system, wherein the electric vehicle thermal management system includes a compressor module and a product under test, a plate heat exchanger and a water-cooled heat exchange device are arranged between the compressor module and the product under test, the water-cooled heat exchange device includes a heat exchanger, antifreeze flows in the heat exchanger and the antifreeze flows to the plate heat exchanger at the heat exchanger, a cavity is provided on the outside of the heat exchanger, the input end of the cavity is respectively connected to the water outlet of a cooling water transmission device and a compressed air transmission device, the output end of the cavity is connected to the water inlet of the cooling water transmission device, and the hybrid cooling method includes:

[0006] Step S1, determining whether a start command input from an external source is received:

[0007] If yes, the water cooling heat exchange device is started, and then the process goes to step S2;

[0008] If not, return to step S1;

[0009] Step S2, detecting a real-time temperature of the antifreeze liquid in the heat exchanger in real time;

[0010] Step S3, determining whether the real-time temperature is greater than a preset temperature:

[0011] If yes, the compressed air transmission device is controlled to be closed and the cooling water transmission device is started, so that the cooling water transmission device outputs cooling water to the cavity to exchange heat with the antifreeze liquid for the first step of cooling, and then turns to step S4;

[0012] If not, return to step S2;

[0013] Step S4, controlling the plate heat exchanger to perform a second step of cooling on the antifreeze liquid output by the heat exchanger.

[0014] In this solution, a water-cooled heat exchange device is additionally provided between the plate heat exchanger and the product under test, and the antifreeze liquid flowing out of the product under test directly exchanges heat with the cooling water in the cavity outside the heat exchanger before passing through the plate heat exchanger. After the first step of cooling of the heat exchanger is completed, the plate heat exchanger performs the second step of cooling. Its cooling efficiency and heat dissipation cooling performance are much higher than the efficiency and performance when the compressor module controls a single plate heat exchanger to cool the antifreeze liquid, and can meet the heat dissipation requirements of the product under test.

[0015] Furthermore, the water-cooled heat exchange device consumes almost no electricity because it uses cooling water circulation to dissipate heat, and can greatly increase the heat dissipation and cooling performance without consuming electricity. After the mixed cooling of the water-cooled heat exchange device and the plate heat exchanger, the power consumption generated by the compressor module will also be greatly reduced, reducing the burden.

[0016] Furthermore, with the addition of the water-cooled heat exchange device, the workload of the plate heat exchanger is greatly reduced, and the failure rate is also greatly reduced, which can effectively improve safety.

[0017] Preferably, after executing step S1, the method further includes:

[0018] Determine whether a stop command from external input is received:

[0019] If so, the water-cooled heat exchange device is controlled to be turned off and the plate heat exchanger is controlled to be started to dissipate the heat of the antifreeze liquid output by the heat exchanger;

[0020] If not, exit.

[0021] Preferably, the input end of the cavity is also connected to a gas release device, and after determining that the real-time temperature is greater than the preset temperature in step S3, the following steps are further included:

[0022] The air release device is controlled to be activated to discharge the air in the cavity.

[0023] Preferably, a low liquid level alarm is further provided in the cavity outside the heat exchanger, and the low liquid level alarm outputs an alarm signal when the real-time liquid level of the cooling water is less than a preset liquid level. Then, after the step S3 controls to close the compressed air transmission device and start the cooling water transmission device so that the cooling water transmission device outputs cooling water to the cavity for heat exchange with the antifreeze liquid for the first step of cooling, the step further includes:

[0024] Determine whether the alarm signal output by the low liquid level alarm is received:

[0025] If yes, then control to close the cooling water transmission device and the compressed air transmission device, and then return to step S2;

[0026] If not, go to step S4.

[0027] Preferably, after determining in step S1 that the start instruction input from the outside is not received, the step further includes:

[0028] The compressed air transmission device is controlled to start and the cooling water transmission device is closed, so that the compressed air device outputs compressed air into the cavity to discharge the cooling water until the low liquid level alarm outputs the alarm signal.

[0029] Preferably, the preset temperature is 40°C.

[0030] Preferably, in step S3, after controlling to close the compressed air transmission device and to open the cooling water transmission device so that the cooling water transmission device outputs cooling water into the cavity to exchange heat with the antifreeze liquid for the first step of cooling, the method further comprises:

[0031] After a delay of 10 seconds, the process goes to step S4.

[0032] Preferably, the heat exchanger is a shell and tube heat exchanger, the input end of the heat exchanger is connected to a first infusion pipe, the output of the heat exchanger is connected to a second infusion pipe, and the second infusion pipe is connected to the plate heat exchanger, so that the plate heat exchanger performs a second step of cooling on the antifreeze output by the heat exchanger.

[0033] Preferably, the water inlet and the water outlet of the cooling water transmission device are both located at the lower part of the heat exchanger, and after the cooling water transmission device is started in step S3, when the coolant leaks, the coolant flows through the bottom of the inner cavity of the heat exchanger at the water inlet to the water outlet. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a flow chart of the steps of the present invention;

[0035] Figure 2 It is a schematic diagram of the structure of the thermal management system of an electric vehicle of the present invention;

[0036] Figure 3 It is a schematic cross-sectional structural diagram of the water-cooled heat exchange device of the present invention;

[0037] Figure 4 It is a side structural schematic diagram of the water-cooled heat exchange device of the present invention;

[0038] Explanation of the reference numerals: 1. compressor module; 2. product under test; 3. plate heat exchanger; 4. water-cooled heat exchange device; 5. heat exchanger; 6. cavity; 7. water outlet; 8. compressed air transmission device; 9. water inlet; 10. air release device; 11. low liquid level alarm.

[0039] Specific method

[0040] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific examples of the present invention are described in detail below with reference to the accompanying drawings.

[0041] In a preferred embodiment of the present invention, based on the above problems existing in the prior art, a hybrid cooling method applicable to a thermal management system of an electric vehicle is provided. Figure 1-4 As shown, the electric vehicle thermal management system includes a compressor module 1 and a product under test 2, a plate heat exchanger 3 and a water-cooled heat exchange device 4 are arranged between the compressor module 1 and the product under test 2, the water-cooled heat exchange device 4 includes a heat exchanger 5, antifreeze flows in the heat exchanger 5 and the antifreeze flows to the plate heat exchanger 3 at the heat exchanger 5, a cavity 6 is provided on the outside of the heat exchanger 5, the input end of the cavity 6 is respectively connected to the water outlet 7 of a cooling water transmission device and a compressed air transmission device 8, the output end of the cavity 6 is connected to the water inlet 9 of the cooling water transmission device, and the mixed cooling method includes:

[0042] Step S1, determining whether a start command input from an external source is received:

[0043] If yes, the water cooling heat exchange device 4 is controlled to start, and then the process goes to step S2;

[0044] If not, return to step S1;

[0045] Step S2, real-time detection of a real-time temperature of the antifreeze liquid in the heat exchanger 5;

[0046] Step S3, determining whether the real-time temperature is greater than a preset temperature:

[0047] If yes, the compressed air transmission device 8 is controlled to be closed and the cooling water transmission device is started, so that the cooling water transmission device outputs cooling water to the cavity 6 to exchange heat with the antifreeze liquid for the first step of cooling, and then turns to step S4;

[0048] If not, return to step S2;

[0049] Step S4, controlling the plate heat exchanger 3 to perform a second step of cooling on the antifreeze liquid output by the heat exchanger 5.

[0050] Specifically, in this embodiment, a water-cooled heat exchange device 4 is added between the plate heat exchanger 3 and the product under test 2. The antifreeze liquid flowing out of the product under test 2 directly exchanges heat with the cooling water in the cavity 6 outside the heat exchanger 5 before passing through the plate heat exchanger 3. After the first step of cooling of the heat exchanger 5 is completed, the plate heat exchanger 3 performs the second step of cooling. Its cooling efficiency and heat dissipation cooling performance are much higher than the efficiency and performance of the compressor module 1 controlling a single plate heat exchanger 3 to cool the antifreeze liquid, and can meet the heat dissipation requirements of the product under test.

[0051] Preferably, the water-cooled heat exchange device 4 has almost no electricity consumption due to the cooling water circulation heat dissipation method, and can greatly increase the heat dissipation and cooling performance without occupying electricity consumption. The power consumption generated by the compressor module 1 after mixed cooling by the water-cooled heat exchange device 4 and the plate heat exchanger 3 will also be greatly reduced, reducing the burden.

[0052] Preferably, with the addition of the water-cooled heat exchange device 4, the workload of the plate heat exchanger 3 is greatly reduced, and the failure rate is also greatly reduced, which can effectively improve safety.

[0053] Preferably, after experimental measurement, the compressor module 1 (cooling 42kW) consumes 14kW of electricity at a heating value of 42kW, while the water-cooled heat exchange device 4 consumes almost no electricity, which can meet the energy-saving requirements.

[0054] Preferably, the water-cooled heat exchange device 4 is placed at the front end of the plate heat exchanger 3, so that the high-temperature antifreeze liquid circulates back and passes through the first step of cooling of the water-cooled heat exchange device 4, and then the second step of cooling is performed by the plate heat exchanger 3 to further adjust the temperature of the antifreeze liquid, which can effectively reduce the electrical power consumption of the compressor module 1 and the plate heat exchanger 3.

[0055] Preferably, the creative use of compressed air in the water-cooled heat exchange device 4 realizes the dual functions of dynamically driving away the cooling water in the heat exchanger 5 and isolating the heat exchange between the cooling water and the antifreeze, so that the electric vehicle management system can use the water-cooled heat exchange device 4 to reduce the load of the compressor module 1 and the plate heat exchanger 3 and reduce energy consumption above the preset temperature. Below the preset temperature, the water-cooled heat exchange device 4 is isolated to avoid adding load to the compressor module 1 and the plate heat exchanger 3, reducing the refrigeration capacity, and increasing energy consumption.

[0056] Specifically, in this embodiment, the cooling water transmission device controls whether the cooling water flows out through the cooling water valve, and the compressed air transmission device 8 controls whether the compressed air flows out through the compressed air intake valve. After the real-time temperature of step S3 is interrupted and is greater than the preset temperature, the compressed air intake valve is controlled to be closed and the cooling water valve is opened, so that the cooling water can enter the cavity outside the heat exchanger to take away the heat of the high-temperature antifreeze.

[0057] In a preferred embodiment of the present invention, after executing step S1, the method further includes:

[0058] Determine whether a stop command from external input is received:

[0059] If yes, the water-cooled heat exchange device 4 is controlled to be turned off and the plate heat exchanger 3 is controlled to be started to dissipate the antifreeze liquid output by the heat exchanger 5;

[0060] If not, exit.

[0061] In a preferred embodiment of the present invention, the input end of the cavity 6 is further connected to a gas release device 10, and after determining that the real-time temperature is greater than the preset temperature in step S3, the following steps are further included:

[0062] The air release device 10 is controlled to be activated to discharge the air in the cavity 6 .

[0063] Specifically, in this embodiment, the air release device 10 is opened and closed by controlling the air release solenoid valve. When it is determined in step S3 that the real-time temperature is greater than the preset temperature, the air release solenoid valve is controlled to open, and the air in the cavity is discharged through the automatic exhaust valve connected to the rear end of the air release solenoid valve.

[0064] Preferably, the automatic exhaust valve can automatically close after exhausting the gas to avoid cooling water leakage.

[0065] In a preferred embodiment of the present invention, a low liquid level alarm 11 is further provided in the cavity 6 outside the heat exchanger 5. The low liquid level alarm 11 outputs an alarm signal when the real-time liquid level of the cooling water is less than the preset liquid level. Then, in step S3, the compressed air transmission device 8 is controlled to be closed and the cooling water transmission device is started, so that the cooling water transmission device outputs the cooling water to the cavity 6 for heat exchange with the antifreeze liquid for the first step of cooling. Then, the following steps are further included:

[0066] Determine whether the alarm signal output by the low liquid level alarm 11 is received:

[0067] If yes, the cooling water transmission device and the compressed air transmission device 8 are controlled to be closed, and then the process returns to step S2;

[0068] If not, go to step S4.

[0069] Specifically, in this embodiment, when the electric vehicle thermal management system does not need the water-cooled heat exchange device 4, it is necessary to open the compressed air intake valve, close the cooling water valve and the air release solenoid valve, and the injected compressed air will gradually drive out the cooling water in the heat exchanger 5 until the low liquid level alarm 11 is triggered, then close the compressed air switch valve to stop injecting compressed air, and at this time the heat exchange between the cooling water and the antifreeze is isolated by the compressed air.

[0070] Preferably, in order to prevent the cooling water from refilling the internal cavity of the heat exchanger 5 due to valve leakage or the like, an additional logic can be added to the control logic: if the alarm signal output by the low liquid level alarm disappears, the compressed air switch valve is reopened to continue injecting compressed air.

[0071] In a preferred embodiment of the present invention, after determining in step S1 that no start instruction from external input is received, the method further includes:

[0072] The compressed air transmission device 8 is controlled to start and the cooling water transmission device is closed, so that the compressed air device outputs compressed air into the cavity 6 to discharge cooling water until the low liquid level alarm 11 outputs an alarm signal.

[0073] Specifically, in this embodiment, considering that when the temperature of the antifreeze is lower than the temperature of the cooling water (experience shows that it is generally below 40°C), if there is still cooling water in the heat exchanger 5 of the water-cooled heat exchange device 4, the antifreeze cooled by the plate heat exchanger 3 will be re-heated by the cooling water with a higher temperature, thereby reducing the refrigeration and cooling capacity of the equipment and increasing the power load. At the same time, it prevents the cooling water in the heat exchanger 5 from freezing and damaging the equipment when the antifreeze is below 0°C. Therefore, in this embodiment, in order to address this problem, at a certain preset temperature, compressed air is output by the compressed air transmission device 8 to discharge the cooling water in the heat exchanger 5 in the water-cooled heat exchange device 4, so that it becomes a cavity, thereby isolating the cooling water and the antifreeze, and preventing the high-temperature cooling water from reheating the low-temperature antifreeze.

[0074] In a preferred embodiment of the present invention, the preset temperature is 40°C.

[0075] Specifically, in this embodiment, considering that the cooling water temperature is generally lower than 35°C, in order to make the electric vehicle thermal management system operate effectively, the water-cooled heat exchange device 4 designed by this method is suitable for an antifreeze temperature of 40°C and above, and the specific temperature value can be adjusted accordingly through the program.

[0076] In a preferred embodiment of the present invention, in step S3, after controlling to close the compressed air transmission device 8 and to open the cooling water transmission device so that the cooling water transmission device outputs cooling water to the cavity 6 for heat exchange with the antifreeze liquid for the first step of cooling, the method further includes:

[0077] After a delay of 10 seconds, go to step S4.

[0078] In a preferred embodiment of the present invention, the heat exchanger 5 is a shell and tube heat exchanger, the input end of the heat exchanger 5 is connected to a first infusion pipe, the output of the heat exchanger 5 is connected to a second infusion pipe, and the second infusion pipe is connected to the plate heat exchanger 3, so that the plate heat exchanger 3 performs a second step of cooling on the antifreeze output by the heat exchanger 5.

[0079] Specifically, in this embodiment, the heat exchanger 5 is designed as a shell and tube heat exchanger, which is placed vertically, and the first infusion tube and the second infusion tube connected at both ends are directly connected to the antifreeze liquid, which can effectively reduce the flow resistance of the system.

[0080] In a preferred embodiment of the present invention, the water inlet 9 and the water outlet 7 of the cooling water transmission device are both located at the lower part of the heat exchanger. After the cooling water transmission device is started in step S3, when the coolant leaks, the coolant flows through the bottom of the inner cavity of the heat exchanger 5 at the water inlet 9 to the water outlet 7 and flows out.

[0081] Specifically, in this embodiment, in order to ensure that compressed air can discharge all the cooling water in the heat exchanger 5, the cooling water inlet pipe and return pipe need to be designed in a U shape. The water-cooled heat exchanger 5 uses compressed air to discharge the cooling water until the plane of the low liquid level alarm 11 at the right end of the U-shaped connecting pipe. The pipe at the left end of the U-shaped connecting pipe and the part of the pipe below the plane of the low liquid level alarm 11 are full of coolant, but are isolated from the temperature-controlled antifreeze by the compressed air in the closed cavity formed by the upper half of the U-shaped connection of the low liquid level alarm 11 plane and the heat exchanger 5.

[0082] Preferably, the water inlet buckle 9 and the water outlet 7 are both at the lower part of the heat exchanger 5, which can prevent a small amount of leaked coolant from entering the bottom of the inner cavity of the heat exchanger 5 from the water inlet 9 and flowing to the water outlet 7 even if the cooling water valve leaks, and is recognized by the low liquid level alarm 11. The control program promptly opens the compressed air inlet valve to discharge the incoming coolant. During this process, the coolant flows through the bottom of the heat exchanger 5 and does not come into contact with the pipeline through which the antifreeze flows for heat exchange.

[0083] Preferably, in order to ensure the cooling capacity of the entire water-cooled heat exchange device 4 at low temperatures, the entire water-cooled heat exchange device 4 needs to be designed for thermal insulation.

[0084] Although the disclosure is disclosed as above, the protection scope of the disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the disclosure, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A hybrid cooling method suitable for an electric vehicle thermal management system, characterized in that: The electric vehicle thermal management system comprises a compressor module (1) and a product to be tested (2), a plate heat exchanger (3) and a water-cooled heat exchange device (4) are arranged between the compressor module (1) and the product to be tested (2), the water-cooled heat exchange device (4) comprises a heat exchanger (5), antifreeze flows in the heat exchanger (5) and the antifreeze flows to the plate heat exchanger (3) at the heat exchanger (5), a cavity (6) is arranged on the outside of the heat exchanger (5), the input end of the cavity (6) is respectively connected to a water outlet (7) of a cooling water transmission device and a compressed air transmission device (8), and the output end of the cavity (6) is connected to a water inlet (9) of the cooling water transmission device. The hybrid cooling method comprises: Step S1, determining whether a start command input from an external source is received: If yes, control the water-cooling heat exchange device (4) to start, and then go to step S2; If not, return to step S1; Step S2, detecting in real time the real-time temperature of the antifreeze liquid in the heat exchanger (5); Step S3, determining whether the real-time temperature is greater than a preset temperature: If so, the compressed air transmission device (8) is controlled to be closed and the cooling water transmission device is started, so that the cooling water transmission device outputs cooling water to the cavity (6) to exchange heat with the antifreeze liquid for the first cooling step, and then the process goes to step S4; If not, return to step S2; Step S4, controlling the plate heat exchanger (3) to perform a second step of cooling on the antifreeze liquid output by the heat exchanger (5); The input end of the cavity (6) is also connected to a gas release device (10), and after determining in step S3 that the real-time temperature is greater than the preset temperature, the step further includes: Controlling and starting the air release device (10) to discharge air from the cavity (6); A low liquid level alarm (11) is also provided in the cavity (6) outside the heat exchanger (5), and the low liquid level alarm (11) outputs an alarm signal when the real-time liquid level of the cooling water is less than a preset liquid level. Then, in step S3, the compressed air transmission device (8) is controlled to be turned off and the cooling water transmission device is started, so that the cooling water transmission device outputs cooling water to the cavity (6) for heat exchange with the antifreeze liquid to perform the first step of cooling, and then the method further includes: Determining whether the alarm signal output by the low liquid level alarm (11) is received: If yes, control to close the cooling water transmission device and the compressed air transmission device (8), and then return to step S2; If not, go to step S4; After determining in step S1 that the start instruction from the external input is not received, the following further comprises: The compressed air transmission device (8) is controlled to start and the cooling water transmission device is controlled to close, so that the compressed air transmission device (8) outputs compressed air into the cavity (6) to discharge the cooling water until the low liquid level alarm (11) outputs the alarm signal.

2. The hybrid cooling method according to claim 1, characterized in that: After executing step S1, the method further includes: Determine whether a stop command from external input is received: If so, controlling the water-cooled heat exchange device (4) to be turned off and controlling the plate heat exchanger (3) to be started to dissipate the heat of the antifreeze liquid output by the heat exchanger (5); If not, exit.

3. The hybrid cooling method according to claim 1, characterized in that: The preset temperature is 40°C.

4. The hybrid cooling method according to claim 1, characterized in that: In step S3, after controlling to close the compressed air transmission device (8) and to open the cooling water transmission device so that the cooling water transmission device outputs cooling water into the cavity (6) to exchange heat with the antifreeze liquid for the first cooling step, the method further comprises: After a delay of 10 seconds, the process goes to step S4.

5. The hybrid cooling method according to claim 1, characterized in that: The heat exchanger (5) is a shell and tube heat exchanger, the input end of the heat exchanger (5) is connected to a first liquid infusion pipe, the output end of the heat exchanger (5) is connected to a second liquid infusion pipe, and the second liquid infusion pipe is connected to the plate heat exchanger (3), so that the plate heat exchanger (3) performs a second step of cooling on the antifreeze output from the heat exchanger (5).

6. The hybrid cooling method according to claim 1, characterized in that: The water inlet (9) and the water outlet (7) of the cooling water transmission device are both located at the lower part of the heat exchanger. After the cooling water transmission device is started in step S3, when the cooling water leaks, the cooling water flows through the bottom of the inner cavity of the heat exchanger (5) at the water inlet (9) and flows out to the water outlet (7).

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