Thermal management system based on grade recycling, control method and vehicle

Abstract

The invention belongs to the technical field of thermal management, and particularly relates to a thermal management system based on grade recycling, a control method and a vehicle, and the thermal management system comprises a phase change refrigerant compression heat pump unit and a non-phase change pump driven cooling liquid unit; the heat pump unit comprises a four-way valve, a compressor, a main heat exchanger refrigerant channel, a throttling valve and an outboard heat exchanger refrigerant channel. The cooling liquid unit comprises a multi-way valve set, a first circulating pump, a second circulating pump, a main heat exchanger cooling liquid channel, a front heat exchanger, an outboard heat exchanger cooling liquid channel and electric drive and electric control equipment. According to the requirements of the environment in the cabin and safe operation of vehicle equipment for the heat grade, the valve element communication modes of the four-way valve and the multi-way valve set are adjusted respectively, and the heat pump unit and the cooling liquid unit can form cold and hot loops of various combination modes. The heat management system based on grade recycling is high in energy efficiency, simple in structure, stable in operation, simple and convenient in control mode and capable of reducing vehicle cost.

Description

Technical Field

[0001] The present invention belongs to the field of thermal management technology, and in particular relates to a thermal management system, a control method and a vehicle based on grade recycling. Background Art

[0002] Vehicle thermal management is one of the core technologies in the development of electric vehicles, which mainly includes air-conditioning circuit (20-25℃), battery circuit (10-35℃) and motor circuit (0-60℃). According to the different functional requirements of each circuit unit, it has the conditions to transfer heat from high level to low level for recycling. When the existing thermal management system recovers heat, no matter what the coolant temperature in the battery and motor circuits is, it is necessary to take heat from the coolant circulation system through a heat pump, improve the quality and then supply heat to the cabin. Although it can realize cooling and heating solutions in the passenger compartment under multiple modes, it is impossible to directly recycle the high-quality heat in the battery and motor. There is a common problem of complex and inefficient system. The existing thermal management technology urgently needs innovation and improvement. Summary of the invention

[0003] In order to solve the problems existing in the prior art, the present invention provides a thermal management system based on grade recovery and utilization, which realizes the efficient utilization and direct recovery of multiple cold and heat sources at different high and low grades, and improves the energy efficiency of the thermal management system. The technical solution of the present invention comprises a main heat exchanger, a front heat exchanger and an outboard heat exchanger. The main heat exchanger and the outboard heat exchanger are both refrigerant-coolant-air three-medium heat exchange structures, and the front heat exchanger is a coolant-air two-medium heat exchange structure. The front heat exchanger and the main heat exchanger are sequentially arranged in the air duct of the air conditioning box in the cabin along the wind direction, and the outboard heat exchanger is placed in the ambient air outside the cabin. The refrigerant channels of the main heat exchanger and the outboard heat exchanger are connected to the four-way valve, the compressor, and the throttle valve to form a phase-change refrigerant heat pump unit based on the switching of the four-way valve; The coolant channels of the main heat exchanger and the outboard heat exchanger are connected to the multi-way valve group, the first circulation pump, the second circulation pump, the front heat exchanger, and the electric drive and electric control equipment to form a pump-driven coolant unit based on the switching of the multi-way valve group; The multi-way valve group has at least 8 external interfaces. After the electric drive and electric control equipment and the first circulating pump are connected in series to form a first pipe section, they are communicated with interfaces 1 and 2 of the multi-way valve group. The cooling liquid channel of the external radiator is communicated with interfaces 3 and 4 of the multi-way valve group. After the front heat exchanger and the second circulating pump are connected in series to form a second pipe section, they are communicated with interfaces 5 and 6 of the multi-way valve group. The cooling liquid channel of the main heat exchanger is communicated with interfaces 7 and 8 of the multi-way valve group. Interfaces 1 and 8 of the multi-way valve group are connected. The valve core communication modes of the four-way valve and the multi-way valve group are adjusted respectively, and the heat pump unit and the coolant unit can form cold and hot circuits in various combinations. Furthermore, it also includes a liquid-cooled battery, which is connected in series in the pipeline between the coolant channel of the main heat exchanger and the 8th interface of the multi-way valve group. Furthermore, it also includes a third circulation pump, and there is a 9th interface between the 7th and 8th interfaces of the multi-way valve group. The third circulation pump is connected in series in the 8th interface pipeline of the multi-way valve group. One end of the third circulation pump is simultaneously connected to the first end of the liquid-cooled battery and the 1st interface of the multi-way valve group, and the second end of the liquid-cooled battery is connected to the 9th interface. Furthermore, it also includes an expansion water tank connected to the first interface of the multi-way valve group. Furthermore, it also includes an auxiliary heater connected in series between the electric drive and electric control device and the second interface of the multi-way valve group. The present invention provides a control method for controlling the operation of the aforementioned thermal management system based on grade recycling. According to the temperature and humidity requirements of the cabin environment, the control method includes four modes: heating, dehumidification, heat dissipation, and cooling. The present invention also provides a second control method for controlling the operation of the aforementioned thermal management system based on grade recycling. According to the dual requirements of temperature and humidity in the cabin environment and the constant temperature of the liquid-cooled battery, the control method includes six modes: heating, dehumidification, heat dissipation, refrigeration, battery cold storage, and battery heat storage. The present invention also provides a third control method for controlling the operation of the aforementioned thermal management system based on grade recycling. According to the dual requirements of temperature and humidity in the cabin environment and constant temperature of the liquid-cooled battery, the control method includes eight modes: heating, dehumidification, heat dissipation, refrigeration, battery cold storage, battery heat storage, active heat dissipation, and active temperature equalization. The present invention also provides a vehicle having the above-mentioned thermal management system based on grade recycling. The vehicles described in the present invention include various types of vehicles that travel on land, in water, and in the air and are driven by electric motors, such as pure electric, oil-electric hybrid, and hydrogen-powered vehicles. The above technical solution of the present invention has the following technical effects: On the one hand, the present invention adopts two three-medium heat exchangers inside and outside the cabin, which are connected with a four-way valve, a compressor, and a throttle valve to form a direct heat pump unit based on the switching of a four-way valve, which has a simple structure, stable operation, and high energy efficiency; On the other hand, the present invention adopts a coolant unit composed of a multi-way valve group, and only by adjusting the valve core position of the multi-way valve group, a variety of cold and hot circuits that meet the needs of the thermal management system based on grade recycling can be formed; The control method of the present invention adjusts the valve core combination mode of the four-way valve and the multi-way valve group according to the temperature and humidity requirements of the cabin environment, so as to realize the efficient cooling and heating mode of the direct heat pump, and realize the indirect and direct recycling of the system waste heat and waste cooling, with simple control logic and stable operation. The vehicle having the thermal management system based on grade recycling of the present invention has a simple structure, stable operation and high energy efficiency. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 It is a schematic diagram of the structure of a thermal management system of a vehicle based on grade recycling of the present invention; Figure 2 It is a schematic diagram of the structure of the thermal management system of the second vehicle based on grade recycling of the present invention; Figure 3 It is a schematic diagram of the structure of a thermal management system based on grade recycling of a third vehicle of the present invention; Figure 4 is a flow chart of a first heating mode of a control method of the present invention; Figure 5 is a flow chart of a second heating mode of a control method of the present invention; Figure 6 is a flow chart of a third heating mode of a control method of the present invention; Figure 7 is a fourth heating mode flow chart of a control method of the present invention; Figure 8 is a fifth heating mode flow chart of a control method of the present invention; Fig. 9 is a sixth heating mode flow chart of a control method of the present invention; Fig.10 is a seventh heating mode flow chart of a control method of the present invention; Fig.11 This is a first heat dissipation mode process of a control method of the present invention Figure 1 ; Fig.12 This is a second heat dissipation mode process of a control method of the present invention Figure 2 ; Fig.13 It is a refrigeration mode flow chart of a control method of the present invention; Fig.14 is a battery cold storage flow chart of the second control method of the present invention; Fig.15 is an active heat dissipation flow chart of the third control method of the present invention; Fig.16 This is the active temperature equalization process of the third control method of the present invention Figure 1 ; Fig.17 This is the active temperature equalization process of the third control method of the present invention Figure 2 ; Fig.18 It is a battery heat storage flow chart of the third control method of the present invention. Reference numerals: 10: Four-way valve; 11: Compressor; 12: Main heat exchanger; 13: Throttle valve; 20: Multi-way valve group; 201: First circulation pump; 202: Second circulation pump; 203: Third circulation pump; 21: Front heat exchanger; 22: Outboard heat exchanger; 23: Electric drive and electronic control equipment; 24: Liquid-cooled battery; 25: Expansion water tank. DETAILED DESCRIPTION Specific embodiment 1 of the thermal management system based on grade recycling of the present invention is as shown in the attached Figure 1 As shown: it includes a main heat exchanger 12, a front heat exchanger 21, and an outboard heat exchanger 22. The main heat exchanger 12 and the outboard heat exchanger 22 are both refrigerant-coolant-air three-medium heat exchange structures, and the front heat exchanger 21 is a coolant-air two-medium heat exchange structure. The front heat exchanger 21 and the main heat exchanger 12 are sequentially arranged in the air duct of the air-conditioning box in the cabin along the wind direction, and the outboard heat exchanger 22 is placed in the ambient air outside the cabin; the refrigerant channels of the main heat exchanger 12 and the outboard heat exchanger 22 are connected with the four-way valve 10, the compressor 11, and the throttle valve 13, forming a phase change refrigerant heat pump unit based on the switching of the four-way valve 10; the coolant channels of the main heat exchanger 12 and the outboard heat exchanger 22 are connected with the multi-way valve group 20, the first circulating pump 201, the second circulating pump 202, the front heat exchanger 21, and the electric drive and electronic control device 23, forming a pump-driven coolant unit based on the switching of the multi-way valve group 20; The multi-way valve group 20 has 8 external interfaces. After the electric drive and electric control equipment 23 and the first circulating pump 201 are connected in series to form a first pipe section, they are communicated with interfaces 1 and 2 of the multi-way valve group 20. The cooling liquid channel of the outboard radiator 22 is communicated with interfaces 3 and 4 of the multi-way valve group 20. After the front heat exchanger 21 and the second circulating pump 202 are connected in series to form a second pipe section, they are communicated with interfaces 5 and 6 of the multi-way valve group 20. The cooling liquid channel of the main heat exchanger 12 is communicated with interfaces 7 and 8 of the multi-way valve group 20. The 1 and 8 interfaces of the multi-way valve group 20 are communicated; By adjusting the valve core communication modes of the four-way valve 10 and the multi-way valve group 20 respectively, the heat pump unit and the coolant unit can form cold and hot circuits in various combinations. Specific embodiment 2 of the thermal management system based on grade recycling of the present invention is as shown in the attached Figure 2 As shown: Based on the structure of the aforementioned specific embodiment 1, this embodiment 2 also includes a liquid-cooled battery 24, and the liquid-cooled battery 24 is connected in series in the pipeline between the coolant channel of the main heat exchanger 12 and the 8th interface of the multi-way valve group 20. Specific embodiment 3 of the thermal management system based on grade recovery and utilization of the present invention is as shown in the attached Figure 3As shown: Based on the structure of the aforementioned specific embodiment 2, this embodiment 3 also includes a third circulation pump 203, and a 9th interface is provided between interfaces 7 and 8 of the multi-way valve group 20. The third circulation pump 203 is connected in series in the pipeline of the 8th interface of the multi-way valve group 20, and one end of the third circulation pump 203 is simultaneously connected to the first end of the liquid-cooled battery 24 and the 1st interface of the multi-way valve group 20, and the second end of the liquid-cooled battery 24 is connected to the 9th interface. In the above embodiments, an expansion water tank 25 connected to the first interface of the multi-way valve group 20 can be provided to maintain constant pressure in the cooling liquid circulation pipeline and balance the liquid replenishment. In the above embodiments, in order to cope with extremely cold weather environments and heat pump failures, an auxiliary heater connected in series between the electric drive and electronic control equipment 23 and the second interface of the multi-way valve group 20 may be provided, such as a water circulation diesel heater, a heat dissipation heat exchanger of the engine system, etc. as a backup heat source. As attached Figures 4 to 13 As shown, the first control method of the present invention includes four modes: heating, dehumidification, heat dissipation, and cooling, which are used to control the operation of the aforementioned thermal management system embodiments 1 to 3 based on grade recovery and utilization; When the air temperature in the cabin is lower than the comfort temperature required by the passengers, the temperature of the coolant of the electric drive and electronic control device 23 is detected. If the coolant of the electric drive and electronic control device 23 is lower than the thermal energy grade of the air outside the cabin, the following steps are executed: Figures 4 to 10 One of the heating or dehumidification modes shown; First heating mode: as attached Figure 4 As shown, the valve core position of the four-way valve 10 is adjusted to heat pump heating, and at the same time, the fan of the off-cabin heat exchanger 22 is running, and the throttle valve 13 cuts off the low-pressure refrigerant after decompression, and evaporates from the ambient air outside the cabin through the refrigerant channel of the off-cabin radiator 22, enters the compressor 11 through the four-way valve 10, and is compressed into a high-pressure refrigerant, and enters the refrigerant channel of the main heat exchanger 12 through the four-way valve 10 again to release heat, and the cycle is repeated. The fan of the cabin air conditioner drives the cabin air to exchange heat with the refrigerant channel of the main heat exchanger 12 to heat the cabin air; This mode is a single air source heat pump mode, the first circulation pump 201 and the second circulation pump 202 are not running, and it is irrelevant to the valve core position of the multi-way valve group 20. Figures 4 to 10 All are acceptable; this mode has simple control, fast speed, stable operation and high energy efficiency. Second heating mode: During the heating process, the temperature of the coolant in the electric drive and electronic control device 23 is periodically detected. If the temperature of the coolant in the electric drive and electronic control device 23 is higher than the thermal energy level of the air outside the cabin, the valve core of the multi-way valve group 20 is adjusted to the position shown in the attached figure. Figure 5At the position shown, the first circulation pump 201, the electric drive and electronic control device 23, the second and third interfaces of the multi-way valve group 20, the coolant channel of the outboard radiator 22, the fourth interface of the multi-way valve group 20, and the first interface form a low-grade heat recovery loop in series. The heat pump unit simultaneously recovers the waste heat of the electric drive and electronic control device 23 to enhance the heating capacity. If the waste heat recovery heat is sufficient, the fan of the outboard radiator 22 can be turned off to further save power consumption and improve system energy efficiency. In this heating mode, in order to speed up the heating speed, the second circulation pump 202 can be started to drive the coolant in the main heat exchanger 12 to exchange heat with the refrigerant channel of the main heat exchanger 12 to increase the temperature, and preheat the air in the cabin through the preheater 21 to increase the total heating capacity of the air conditioner; This mode is a dual heating mode of waste heat source + air source heat pump. This mode has strong environmental adaptability and fast heating speed. The third heating mode: During the heating process, the coolant temperature of the electric drive and electronic control device 23 is periodically detected. If the coolant temperature of the electric drive and electronic control device 23 is higher than 35°, the valve core of the multi-way valve group 20 is adjusted to the position shown in the attached figure. Figure 6 At the position shown, the first circulation pump 201, the electric drive and electric control device 23, the second interface and the fifth interface of the multi-way valve group 20, the front heat exchanger 21, the second circulation pump 202, the sixth interface and the first interface of the multi-way valve group 20 form a high-quality heat recovery loop in series. This mode is a dual-source cascade heating of high-grade waste heat + air source heat pump. While the air source heat pump is heating, the high-grade waste heat of the electric drive and electronic control equipment 23 directly preheats the cabin air through the preheater 21, and forms a dual-source cascade heating with the refrigerant channel of the main heat exchanger 12; This mode has a strong heating capacity and also has the functions of replacing the heat exchanger 21 before drying and preventing mildew. Fourth heating mode: During the heating process, the coolant temperature of the electric drive and electronic control device 23 is periodically detected. If the coolant temperature of the electric drive and electronic control device 23 is higher than 40°, the valve core of the multi-way valve group 20 is adjusted to the position shown in the attached figure. Figure 7 At the position shown, the first circulation pump 201, the electric drive and electric control device 23, the second and seventh interfaces of the multi-way valve group 20, and the coolant channel of the main heat exchanger 12 form a high-grade heat recovery loop in series; This mode is a dual-source same-level heating of high-grade waste heat + air source heat pump. While the air source heat pump is heating, the high-grade waste heat of the electric drive and electric control equipment 23 directly passes through the coolant channel of the main heat exchanger 12 and the refrigerant channel of the main heat exchanger 12 to form dual-source same-level heating; This mode has strong heating capacity, fast heating speed, and high reliability of dual-source backup. Fifth heating mode: During the heating process, the coolant temperature of the electric drive and electronic control device 23 and the humidity of the air in the cabin are periodically detected. If the coolant temperature of the electric drive and electronic control device 23 is higher than 40° and the humidity of the air in the cabin is lower than the comfortable humidity required by the passengers, or the vehicle windshield is fogged up and affects driving safety, the valve core of the multi-way valve group 20 is adjusted to the position shown in the attached figure. Figure 8 At the position shown, on the one hand, the coolant channel of the outboard radiator 22, the 4th and 5th interfaces of the multi-way valve group 20, the front heat exchanger 21, the second circulation pump 202, the 6th and 3rd interfaces of the multi-way valve group 20 form a series waste cold recovery and dehumidification circuit; on the other hand, the first circulation pump 201, the electric drive and electric control device 23, the 2nd and 7th interfaces of the multi-way valve group 20, and the coolant channel of the main heat exchanger 12 form a series high-quality heat recovery circuit; This mode is waste cooling dehumidification + dual-source heat recovery. In this mode, the heat pump operates in the heat pump heating mode. The fan of the radiator 22 outside the cabin can be turned on or off. The fan of the air conditioning box in the cabin drives the cabin air to be cooled and dehumidified by the front heat exchanger 21, and then the dual-source heat recovery is carried out through the refrigerant channel and the coolant channel of the main heat exchanger 12. This mode recovers the free cooling energy of the radiator 22 outside the cabin for pre-cooling and dehumidification in the cabin, and then recovers the waste heat of the electric drive and electronic control equipment 23 to make the air in the cabin recover and heat up or maintain a constant temperature; the control is simple, stable and reliable, and highly efficient and energy-saving. Sixth heating mode: During the heating process, the coolant temperature of the electric drive and electronic control device 23 is periodically detected. If the coolant temperature of the electric drive and electronic control device 23 is higher than 35°, the operation of the heat pump compressor and the fan of the outer radiator 22 is shut down, and the valve core of the multi-way valve group 20 is adjusted to the position shown in the attached figure. Fig. 9 At the position shown, the first circulation pump 201, the electric drive and electric control device 23, the second interface and the fifth interface of the multi-way valve group 20, the front heat exchanger 21, the second circulation pump 202, the sixth interface and the first interface of the multi-way valve group 20 form a high-grade heat recovery loop in series; This mode is a single high-grade waste heat heating mode, in which the high-grade waste heat of the electric drive and electric control equipment 23 is directly recovered and heated through the preheat exchanger 21 to heat the cabin air; This mode recovers waste heat and has high system energy efficiency, and also has the functions of pre-drying heat exchanger 21 and preventing mildew. Seventh heating mode: During the heating process, the coolant temperature of the electric drive and electronic control device 23 is periodically detected. If the coolant temperature of the electric drive and electronic control device 23 is higher than 40°, the operation of the heat pump compressor and the fan of the radiator 22 outside the cabin is shut down, and the valve core of the multi-way valve group 20 is adjusted to the position shown in the attached figure. Fig.10 At the position shown, the first circulation pump 201, the electric drive and electric control device 23, the second and seventh interfaces of the multi-way valve group 20, and the coolant channel of the main heat exchanger 12 form a high-grade heat recovery loop in series; This mode is a single high-grade waste heat heating mode, in which the high-grade waste heat of the electric drive and electric control equipment 23 is directly recovered and heated through the coolant channel of the main heat exchanger 12 to heat the cabin air; This mode recovers waste heat and has high system energy efficiency. When the cabin air temperature is at the comfortable temperature required by the passengers, the heat pump compressor is turned off, and the temperature of the coolant of the electric drive and electronic control device 23 is detected. If the coolant of the electric drive and electronic control device 23 is higher than the safe operating temperature required by the device, the following steps are executed: Fig.11 , 12 One of the cooling modes shown; First heat dissipation mode: adjust the valve core of the multi-way valve group 20 to the following Fig.11 At the position shown, the first circulation pump 201, the electric drive and electric control device 23, the second and third interfaces of the multi-way valve group 20, the coolant passage of the outboard radiator 22, the fourth and fifth interfaces of the multi-way valve group 20, the front heat exchanger 21, the sixth and first interfaces of the multi-way valve group 20 form a series heat dissipation circuit; This mode is a dual cooling mode inside and outside the cabin. The fans of the cabin radiator 22 and the front heat exchanger 21 operate simultaneously or independently. The waste heat of the electric drive and electronic control equipment 23 is released to the cabin air or cabin air through the coolant channel of the cabin radiator 22 and the front heat exchanger 21. Under the premise of ensuring that the indoor air is at the most comfortable temperature, the safe operation of the vehicle equipment is guaranteed. This mode is simple to control and energy-efficient. Second cooling mode: Adjust the valve core of the multi-way valve group 20 to the following Fig.12 At the position shown, the first circulation pump 201, the electric drive and electric control device 23, the second and third interfaces of the multi-way valve group 20, the coolant channel of the outboard radiator 22, the fourth and first interfaces of the multi-way valve group 20 form a series heat dissipation circuit; This mode is a single heat dissipation mode outside the cabin. The outside cabin radiator 22 is running, the second circulation pump 202 and the fan of the front heat exchanger 21 are stopped, and the waste heat of the electric drive and electronic control equipment 23 is released to the outside cabin air through the coolant channel of the outside cabin radiator 22 to ensure the safe operation of the vehicle equipment. This mode is simple to control and energy-efficient. When the air temperature in the cabin is higher than the comfort temperature required by the passengers, the valve core position of the four-way valve 10 is adjusted to heat pump cooling, and at the same time, the fan of the off-cabin heat exchanger 22 is running, and the low-pressure refrigerant after throttling and decompression by the throttle valve 13 enters the refrigerant channel of the main heat exchanger 12. The fan of the cabin air conditioner drives the cabin air to exchange heat and cool down with the refrigerant channel of the main heat exchanger 12. The evaporated refrigerant enters the compressor 11 through the four-way valve 10, is compressed into high-pressure refrigerant, and enters the refrigerant channel of the off-cabin radiator 22 through the four-way valve 10 again, releasing heat to the ambient air outside the cabin, and the cycle repeats; This mode is a direct heat pump cooling mode, in which the first circulation pump 201 and the second circulation pump 202 are not running, and has nothing to do with the valve core position of the multi-way valve group 20. Figures 4 to 10 All are acceptable; this mode has simple control, fast speed, stable operation and high energy efficiency. When the valve core of the multi-way valve group 20 is adjusted to the Fig.13 In the position shown, the first circulation pump 201, the electric drive and electronic control device 23, the second interface and the third interface of the multi-way valve group 20, the coolant channel of the outboard radiator 22, the fourth interface and the first interface of the multi-way valve group 20 form a heat dissipation circuit of the electric drive and electronic control device 23 in series; in this mode, the refrigerant channel and the coolant channel of the outboard radiator 22 simultaneously exchange heat with the outboard air; This mode has simple control, high cooling efficiency, and can also dissipate heat for the electric drive and electronic control equipment 23 . The second control method of the present invention includes six modes: heating, dehumidification, heat dissipation, refrigeration, battery cold storage, and battery heat storage, which are used to control the operation of the aforementioned thermal management system embodiment 2 based on grade recycling. The four modes of heating, dehumidification, heat dissipation and cooling in this control method are basically the same as the four modes of heating, dehumidification, heat dissipation and cooling in the aforementioned control method. General technicians can refer to 2 Attachment Figures 4 to 13 and the accompanying drawings, combined with the aforementioned technical documents, to understand its process and function, which will not be repeated here, the only difference is that during the process of adjusting the temperature and humidity of the cabin air, the liquid-cooled battery 24 connected in series to the coolant channel of the main heat exchanger 12 is synchronously adjusted and controlled; The battery cold storage mode of this control method is as follows Fig.14 As shown, during the heat pump cooling process, when the cabin temperature reaches the preset comfortable temperature, the compressor 10 continues to operate efficiently, the speed of the fan of the cabin air-conditioning box is reduced or shut down, and the second circulation pump 202 is started to operate, and the liquid-cooled battery 24 continues to cool down until the optimal temperature lower limit (10°) of the liquid-cooled battery 24 is reached. The liquid-cooled battery 24 has a large thermal capacity and can store more cold energy; the compressor is turned off, the second circulation pump 202 continues to operate, and the fan of the cabin air-conditioning box is started at an appropriate time, and the liquid-cooled battery 24 releases cold energy to the cabin air, making the cabin comfortable, reducing the frequency of starting and stopping or speed regulation of the compressor, and improving refrigeration energy efficiency. The battery heat storage mode of this control method is as follows Figure 2 As shown, and refer to the attached Figure 5 , 7, 8, 10. During the heat pump heating process, when the cabin temperature reaches the preset comfortable temperature, the compressor 10 continues to operate efficiently, the speed of the fan of the cabin air-conditioning box is reduced or shut down, the second circulation pump 202 is started to operate, and the liquid-cooled battery 24 continues to heat until the optimal temperature upper limit (40°) of the liquid-cooled battery 24 is reached. The liquid-cooled battery 24 has a large thermal capacity and can store more heat; the compressor is turned off, the second circulation pump 202 continues to operate, and the fan of the cabin air-conditioning box is started at an appropriate time. The liquid-cooled battery 24 releases heat to the cabin air, making the cabin comfortable, reducing the frequency of starting and stopping or speed regulation of the compressor, and improving heating energy efficiency. The third control method of the present invention includes 8 modes: heating, dehumidification, heat dissipation, refrigeration, battery cold storage, battery heat storage, active heat dissipation, and active temperature equalization, which are used to control the operation of the aforementioned thermal management system embodiment 3 based on grade recycling; The six modes of heating, dehumidification, heat dissipation, refrigeration, battery cold storage, and battery heat storage in this control method are basically the same as the six modes of heating, dehumidification, heat dissipation, refrigeration, battery cold storage, and battery heat storage in the aforementioned second control method. General technicians can refer to the attached Figure 2 and attached Figures 4 to 14 , combined with the above technical documents, understand its process and function, no further description is given here, the only difference is that, since the coolant system is provided with a third circulation pump 203, the third circulation pump 203 is connected in series with the liquid-cooled battery 24, the active heat dissipation and active temperature equalization functions of the liquid-cooled battery 24 can be realized; The active cooling mode of this control method is as follows Fig.15 As shown, when it is detected that the temperature of the liquid-cooled battery 24 is high and needs to be cooled, it is only necessary to adjust the valve core of the multi-way valve group 20 to the position shown in the attached figure. Fig.15 At the position shown, the third circulation pump 203 and the fan of the off-board heat exchanger 22 are started, and the waste heat of the liquid-cooled battery 24 is directly released into the air outside the cabin through the off-board heat exchanger 22. The active temperature averaging mode of this control method is shown in the attached Fig.16 , 17 As shown, during the heat pump heating process, when it is detected that the temperature consistency of the battery core of the liquid-cooled battery 24 is poor, the valve core of the multi-way valve group 20 is adjusted to the position shown in the attached figure. Fig.16 Or the position shown in 17, start the third circulation pump 203 and the internal circulation of the coolant of the liquid-cooled battery 24 to achieve the battery temperature equalization function. Since the multi-way valve group 20 is provided with a ninth interface, as shown in the attached Fig.18 As shown, the liquid-cooled battery 24, the first circulation pump 201, and the electric drive and electric control device 23 form a series circuit through the second and ninth interfaces of the multi-way valve group 20. The control method has the following characteristics: Fig.18 The battery heat storage mode directly supplied by the electric drive and electronic control device 23 is shown. The vehicle with the above-mentioned thermal management system based on grade recycling described in the present invention includes pure electric, oil-electric hybrid, and hydrogen-powered vehicles that can travel on land, in water, and in the air and are driven by electric motors. It has a simple structure, high efficiency and stability, and low cost.

Claims

1. A thermal management system based on grade recycling, characterized in that: The invention comprises a main heat exchanger (12), a front heat exchanger (21), and an off-board heat exchanger (22); the main heat exchanger (12) and the off-board heat exchanger (22) are both refrigerant-coolant-air three-medium heat exchange structures, the front heat exchanger (21) is a coolant-air two-medium heat exchange structure, the front heat exchanger (21) and the main heat exchanger (12) are sequentially arranged in the air duct of the air conditioner in the cabin along the wind direction, and the off-board heat exchanger (22) is placed in the ambient air outside the cabin; The refrigerant channels of the main heat exchanger (12) and the offboard heat exchanger (22) are connected to the four-way valve (10), the compressor (11), and the throttle valve (13), forming a phase-change refrigerant heat pump unit based on the switching of the four-way valve (10); The cooling liquid channels of the main heat exchanger (12) and the outboard heat exchanger (22) are connected to the multi-way valve group (20), the first circulation pump (201), the second circulation pump (202), the preheat exchanger (21), and the electric drive and electric control device (23), forming a pump-driven cooling liquid unit based on the switching of the multi-way valve group (20); The multi-way valve group (20) has at least 8 external interfaces. After the electric drive and electric control device (23) and the first circulation pump (201) are connected in series to form a first pipe section, they are communicated with interfaces 1 and 2 of the multi-way valve group (20). The cooling liquid channel of the external radiator (22) is communicated with interfaces 3 and 4 of the multi-way valve group (20). After the front heat exchanger (21) and the second circulation pump (202) are connected in series to form a second pipe section, they are communicated with interfaces 5 and 6 of the multi-way valve group (20). The cooling liquid channel of the main heat exchanger (12) is communicated with interfaces 7 and 8 of the multi-way valve group (20). Interfaces 1 and 8 of the multi-way valve group (20) are communicated. The valve core communication modes of the four-way valve (10) and the multi-way valve group (20) are adjusted respectively, and the heat pump unit and the coolant unit can form cold and hot circuits in various combinations.

2. The thermal management system based on grade recovery and utilization as claimed in claim 1, characterized in that: It also includes a liquid-cooled battery (24), which is connected in series in a pipeline between the cooling liquid channel of the main heat exchanger (12) and the eighth interface of the multi-way valve group (20).

3. The thermal management system based on grade recovery and utilization as claimed in claim 2, characterized in that: It also includes a third circulation pump (203), and a ninth interface is provided between interfaces 7 and 8 of the multi-way valve group (20). The third circulation pump (203) is connected in series in the pipeline of the eighth interface of the multi-way valve group (20), and one end of the third circulation pump (203) is simultaneously connected to the first end of the liquid-cooled battery (24) and the first interface of the multi-way valve group (20), and the second end of the liquid-cooled battery (24) is connected to the ninth interface.

4. The thermal management system based on grade recovery and utilization according to any one of claims 1 to 3, characterized in that: It also includes an expansion water tank (25) which is in communication with the first interface of the multi-way valve group (20).

5. The thermal management system based on grade recovery and utilization as claimed in claim 4, characterized in that: It also includes an auxiliary heater connected in series between the electric drive and electric control device (23) and the second interface of the multi-way valve group (20).

6. A control method for controlling the operation of the thermal management system based on grade recovery and utilization as claimed in any one of claims 1 to 5, characterized in that: Based on the temperature and humidity requirements of the cabin environment, the control methods include four modes: heating, dehumidification, heat dissipation, and cooling.

7. A control method for controlling the operation of the thermal management system based on grade recovery and utilization as claimed in claim 2, characterized in that: Based on the temperature and humidity of the cabin environment and the dual requirements of constant temperature of the liquid-cooled battery, the control methods include six modes: heating, dehumidification, heat dissipation, refrigeration, battery cold storage, and battery heat storage.

8. A control method for controlling the operation of the thermal management system based on grade recovery and utilization as claimed in claim 3, characterized in that: Based on the temperature and humidity of the cabin environment and the dual requirements of constant temperature of the liquid-cooled battery, the control methods include 8 modes: heating, dehumidification, heat dissipation, refrigeration, battery cold storage, battery heat storage, active heat dissipation, and active temperature equalization.

9. A vehicle, characterized in that: A thermal management system based on grade recovery and utilization comprising any one of claims 1 to 5.

10. A vehicle as claimed in claim 9, characterized in that: The vehicles include a variety of pure electric, hybrid, and hydrogen-powered vehicles that travel on land, water, and air and are driven by electric motors.

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