Double-compressor refrigerating system for electric vehicle, control method and vehicle

Abstract

The invention provides a double-compressor refrigerating system for an electric vehicle, which comprises a battery cooling liquid loop on which a second heat exchanger and a first heat exchanger are arranged in parallel; an evaporator is arranged on the passenger compartment cooling loop; the main refrigerant loop is at least connected with one of the evaporator and the second heat exchanger through a switching assembly; an auxiliary refrigerant circuit connected to the first heat exchanger; the compressor displacement in the auxiliary refrigerant circuit is less than the compressor displacement in the main refrigerant circuit. The auxiliary refrigerant loop adopts a small-displacement compressor, is started to act on the first heat exchanger when the battery is in low load, and closes the main refrigerant loop, so that the operation energy consumption is lower, and the energy efficiency waste of the main refrigerant loop is avoided; the heat exchanger can be suitable for the high-load working condition, the auxiliary refrigerant loop is started preferentially, the main refrigerant loop is started when the auxiliary refrigerant loop cannot meet the temperature suppression requirement, the main refrigerant loop acts on the second heat exchanger through the switching assembly, and therefore the high-load working condition is met.

Description

Technical Field

[0001] The present application relates to the field of electric vehicle refrigeration technology, and in particular to a dual-compressor refrigeration system, a control method, and a vehicle for an electric vehicle. Background Art

[0002] With the rapid development of electric vehicles, users are increasingly demanding fast-charging efficiency and enhanced passenger compartment comfort, placing higher demands on the cooling capabilities of thermal management systems. Traditionally, to meet the dual cooling needs of the passenger compartment and power battery, a single-compressor parallel refrigeration system has been employed. This system uses a single compressor to drive the parallel passenger compartment and battery cooling circuits, and an electronic expansion valve to adjust the cooling capacity distribution. However, in fast-charging scenarios, the high current charging of the power battery generates extremely high heat loads, and a single compressor cannot simultaneously meet the peak cooling demands of both the passenger compartment and the battery, resulting in uncontrolled battery temperature rise and reduced charging efficiency.

[0003] Therefore, based on the single compressor, the existing technology also proposes a dual-compressor independent refrigeration system, which usually adopts a fixed distribution mode, one dedicated to the passenger compartment and the other dedicated to the battery; and as the battery power of commercial vehicles increases and the battery charging rate increases, this mode requires an increase in the displacement of the battery refrigeration compressor, and large-displacement compressors are expensive and difficult to control to a low speed. This will cause the cooling capacity provided by the thermal management system to be greater than the cooling capacity demand of the battery under low-load conditions of the system, resulting in energy waste. Summary of the Invention

[0004] The embodiments of the present application provide a dual-compressor refrigeration system, control method, and vehicle for electric vehicles to solve the problem in the related art that the vehicle refrigeration system cannot simultaneously meet the cooling needs of the passenger compartment and the power battery under high load, and the energy waste caused by redundant cooling capacity distribution under low load conditions.

[0005] In a first aspect, a dual-compressor refrigeration system for an electric vehicle is provided, comprising: a battery coolant circuit on which a second heat exchanger and a first heat exchanger are arranged in parallel; a passenger compartment cooling circuit on which an evaporator is provided; a main refrigerant circuit connected to at least one of the evaporator and the second heat exchanger through a switching component; and an auxiliary refrigerant circuit connected to the first heat exchanger; the compressor displacement in the auxiliary refrigerant circuit is smaller than the compressor displacement in the main refrigerant circuit.

[0006] In some embodiments, the battery cooling liquid circuit is provided with a first temperature detection module; the passenger cabin cooling circuit is provided with a second temperature detection module; the switching assembly comprises a first electronic expansion valve and a second electronic expansion valve; the main refrigerant circuit comprises a first compressor, a first condenser, a first temperature and pressure detection module connected in sequence, and is connected to the evaporator through the first electronic expansion valve and to the second heat exchanger through the second electronic expansion valve; the auxiliary refrigerant circuit comprises a second compressor, a second condenser, a second temperature and pressure detection module connected in sequence, and is connected to the first heat exchanger through the third electronic expansion valve.

[0007] In some embodiments, the system further comprises a control module; the control module is configured to adjust the opening degree of the first electronic expansion valve, the second electronic expansion valve and the third electronic expansion valve according to the refrigerant supercooling degree fed back by the first temperature and pressure detection module and the second temperature and pressure detection module; the control module is further configured to control the start-stop and rotation speed of the first compressor and the second compressor according to the battery inlet cooling liquid temperature and the evaporation temperature of the evaporator fed back by the first temperature detection module and the second temperature detection module.

[0008] In some embodiments, the system further comprises a control module; the switching assembly comprises a first electronic expansion valve and a second electronic expansion valve connected in parallel; the main refrigerant circuit comprises a first compressor, a first condenser, a first temperature and pressure detection module connected in sequence, and is connected to the evaporator through the first electronic expansion valve and to the second heat exchanger through the second electronic expansion valve; the auxiliary refrigerant circuit comprises a second compressor, a second condenser, a second temperature and pressure detection module connected in sequence, and is connected to the first heat exchanger through the third electronic expansion valve; when the vehicle is in the driving state and the passenger cabin has no refrigeration demand and the power battery has refrigeration demand, the control module executes the first strategy, which comprises the following contents: acquiring the first real-time temperature of the battery inlet cooling liquid in real time; the control module only starts the second compressor, and gradually increases the opening degree of the third electronic expansion valve according to the first difference between the first real-time temperature and the first target temperature until the first difference is less than the first allowable threshold.

[0009] In some embodiments, the system further comprises a control module; the switching assembly comprises a first electronic expansion valve and a second electronic expansion valve connected in parallel; the main refrigerant circuit comprises a first compressor, a first condenser, a first temperature and pressure detection module connected in sequence, and is connected to the evaporator through the first electronic expansion valve and to the second heat exchanger through the second electronic expansion valve; the auxiliary refrigerant circuit comprises a second compressor, a second condenser, a second temperature and pressure detection module connected in sequence, and is connected to the first heat exchanger through the third electronic expansion valve; when the vehicle is in the driving state and the passenger cabin has no refrigeration demand and the power battery has refrigeration demand, the control module executes the first strategy, which comprises the following contents: acquiring the first real-time temperature of the battery inlet cooling liquid in real time; the control module only starts the second compressor, and gradually increases the opening degree of the third electronic expansion valve according to the first difference between the first real-time temperature and the first target temperature until the first difference is less than the first allowable threshold.

[0010] In some embodiments, when the vehicle is in the charging state, the passenger cabin has no refrigeration demand, and the power battery has a refrigeration demand, the control module executes a second strategy, which includes the following: the control module executes the first strategy; if the opening degree of the third electronic expansion valve is adjusted to the maximum, and the first difference is still not less than the first allowable threshold, the control module starts the first compressor, closes the first electronic expansion valve, and gradually increases the opening degree of the second electronic expansion valve until the first difference is less than the first allowable threshold.

[0011] In some embodiments, when the vehicle is in the driving state, the passenger cabin has a refrigeration demand, and the power battery has a refrigeration demand, the control module executes a third strategy, which includes the following: the first real-time temperature of the battery inlet cooling liquid and the second real-time temperature of the evaporator evaporation are obtained in real time; the control module starts the first compressor and the second compressor at the same time; the control module closes the second electronic expansion valve; the control module gradually increases the opening degree of the third electronic expansion valve until the first difference between the first real-time temperature and the first target temperature is less than the first allowable threshold; the control module gradually increases the opening degree of the first electronic expansion valve until the second difference between the second real-time temperature and the target evaporation temperature is less than the second allowable threshold.

[0012] In some embodiments, when the vehicle is in the charging state, the passenger cabin has a refrigeration demand, and the power battery has a refrigeration demand, the control module executes a fourth strategy, which includes the following: the control module executes the third strategy, and does not close the second electronic expansion valve; if the opening degree of the third electronic expansion valve is adjusted to the maximum, and the first difference is still not less than the first allowable threshold, the control module starts the first compressor, and gradually increases the opening degree of the second electronic expansion valve until the first difference is less than the first allowable threshold.

[0013] In some embodiments, when the vehicle is in other states, the control module executes the following steps according to the refrigeration demand: when the passenger cabin and the power battery have no refrigeration demand, it is judged whether the vehicle is currently in the refrigeration state, if yes, the refrigeration is closed, otherwise, the closed refrigeration state is maintained; when the passenger cabin has a refrigeration demand, and the power battery has no refrigeration demand, the control module executes a fifth strategy, which includes obtaining the second real-time temperature of the evaporator evaporation in real time, the control module only starts the first compressor, closes the second electronic expansion valve, and gradually increases the opening degree of the first electronic expansion valve until the difference between the second real-time temperature and the target evaporation temperature is less than the second allowable threshold.

[0014] In a third aspect, a vehicle including a dual-compressor refrigeration system for an electric vehicle is provided.

[0015] The technical scheme provided by the embodiments of the present application has the following beneficial effects: Embodiments of the present application provide a dual-compressor refrigeration system, control method, and vehicle for electric vehicles, wherein an auxiliary refrigerant circuit utilizes a small-displacement compressor. When the battery is under low load, the small-displacement auxiliary refrigerant circuit is activated to act on the first heat exchanger of the battery coolant circuit, while the main refrigerant circuit is shut down. This results in lower operating energy consumption and avoids energy waste in the main refrigerant circuit. Furthermore, the system is also applicable to charging scenarios under high load conditions. In this case, the auxiliary refrigerant circuit is activated preferentially. If it cannot meet the battery temperature suppression requirements, the main refrigerant circuit is activated, and a switching component is used to direct the main refrigerant circuit to act on the second heat exchanger, thereby meeting the requirement of suppressing the temperature rise of the power battery under high load conditions. Furthermore, this adjustable dual-compressor mode can start and stop the main and auxiliary refrigerant circuits accordingly according to different vehicle conditions and cooling requirements. Depending on the adjustment of the switching component, the main refrigerant circuit can act on the evaporator or the second heat exchanger alone, or on both the evaporator and the second heat exchanger simultaneously, thereby meeting more application scenarios and improving the compatibility of the system. The invention solves the problem in related technologies that the vehicle refrigeration system cannot simultaneously meet the cooling needs of the passenger compartment and the power battery under high load, and the energy waste caused by redundant cooling capacity distribution under low load conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of a dual-compressor refrigeration system provided in an embodiment of the present application; Figure 2 A schematic flow chart of a dual-compressor refrigeration control method provided in an embodiment of the present application; Figure 3 A schematic diagram of the control strategy flow provided in an embodiment of the present application.

[0017] In the figure: 1. Evaporator; 2. Second heat exchanger; 3. First heat exchanger; 4. First electronic expansion valve; 5. Second electronic expansion valve; 6. Third electronic expansion valve; 7. First temperature and pressure detection module; 8. Second temperature and pressure detection module; 9. First temperature detection module; 10. Second temperature detection module; 11. First compressor; 12. Second compressor; 13. First condenser; 14. Second condenser; 15. Expansion water tank; 16. Electronic water pump; 17. Battery pack. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0019] In order to make the technical problem to be solved by this application clearer, the causes of the technical problem will be specifically analyzed below.

[0020] A single compressor system has insufficient cooling capacity under the high-load conditions of fast-charging scenarios. This is specifically manifested by a limited cooling capacity. The maximum cooling capacity of a single compressor is determined by its displacement and speed. In fast-charging scenarios, the high current charging of the power battery generates an extremely high heat load, which is compounded by the load generated by passenger compartment cooling. The total cooling demand easily exceeds the maximum output of a single compressor, making it impossible to meet both requirements simultaneously.

[0021] However, dual-compressor systems waste energy under low-load conditions due to mismatched displacement. To meet fast-charging requirements, traditional dual-compressor systems require a large-displacement compressor on the battery side. However, under low-load conditions, even at the lowest speed, the large-displacement compressor still produces far more cooling capacity than required, resulting in energy waste.

[0022] Moreover, the traditional single-compressor system distributes the cooling capacity in parallel through an electronic expansion valve, and the dual-compressor system adopts a fixed distribution mode, with one compressor dedicated to the passenger compartment and the other dedicated to the battery pack 17, and cannot dynamically adjust the operating status according to real-time demand.

[0023] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0024] In the first aspect, the embodiment of the present application provides a dual compressor refrigeration system for electric vehicles, referring to Figure 1 , Figure 1 This is a schematic diagram of a dual compressor refrigeration system provided in an embodiment of the present application. Figure 1 As shown, a dual-compressor refrigeration system for an electric vehicle includes: a battery coolant circuit, on which a second heat exchanger 2 and a first heat exchanger 3 are arranged in parallel; a passenger compartment cooling circuit, on which an evaporator 1 is provided; a main refrigerant circuit, which is connected to at least one of the evaporator 1 and the second heat exchanger 2 through a switching component; an auxiliary refrigerant circuit, which is connected to the first heat exchanger 3; the compressor displacement in the auxiliary refrigerant circuit is smaller than the compressor displacement in the main refrigerant circuit.

[0025] By setting such a system, wherein the auxiliary refrigerant circuit adopts a small-capacity compressor, at low load, the small-capacity auxiliary refrigerant circuit is started to act on the first heat exchanger 3 of the battery cooling liquid circuit, and the main refrigerant circuit is closed, the energy consumption is lower, and the energy efficiency waste of the main refrigerant circuit is avoided; and it can also be applied to the charging scene under high load, at this time, only the auxiliary refrigerant circuit needs to be started preferentially, and in the case that the battery temperature cannot be inhibited, the main refrigerant circuit is started, and the main refrigerant circuit acts on the second heat exchanger 2 through the switching assembly, so as to meet the demand of inhibiting the temperature rise of the power battery under high load; at the same time, this adjustable double-compressor mode can start and stop the main refrigerant circuit and the auxiliary refrigerant circuit according to other different vehicle states and refrigeration demands, and make the main refrigerant circuit act on the evaporator 1 or the second heat exchanger 2 alone or act on the evaporator 1 and the second heat exchanger 2 at the same time according to the adjustment of the switching assembly, so as to meet more application scenarios and improve the compatibility of the system. The problem of energy waste caused by the refrigeration capacity distribution redundancy of the vehicle refrigeration system in the related art cannot meet the refrigeration demand of the passenger compartment and the power battery under high load at the same time.

[0026] In some preferred embodiments, the battery cooling liquid circuit is provided with a first temperature detection module 9; the passenger compartment cooling circuit is provided with a second temperature detection module 10; the switching assembly includes a first electronic expansion valve 4 and a second electronic expansion valve 5; the main refrigerant circuit includes a first compressor 11, a first condenser 13, and a first temperature and pressure detection module 7 connected in sequence, and is connected with the evaporator 1 through the first electronic expansion valve 4 and connected with the second heat exchanger 2 through the second electronic expansion valve 5; the auxiliary refrigerant circuit includes a second compressor 12, a second condenser 14, and a second temperature and pressure detection module 8 connected in sequence, and is connected with the first heat exchanger 3 through a third electronic expansion valve 6.

[0027] This embodiment specifically defines the structures of the main and auxiliary refrigerant circuits. Specifically, the main refrigerant circuit includes a first compressor 11, a first condenser 13, and a first temperature and pressure detection module 7. It is connected to the evaporator 1 via a first electronic expansion valve 4, and to the second heat exchanger 2 via a second electronic expansion valve 5. The evaporator 1 is used to cool the passenger compartment, and the second heat exchanger 2 is used to cool the power battery. The auxiliary refrigerant circuit includes a second compressor 12, a second condenser 14, and a second temperature and pressure detection module 8. It is connected to the first heat exchanger 3 via a third electronic expansion valve 6. The first heat exchanger 3 is used to cool the power battery. Specifically, the main and auxiliary refrigerant circuits are separated, and refrigerant distribution is achieved through electronic expansion valves. The main circuit controls the cooling capacity of the passenger compartment and the battery through the first and second electronic expansion valves 5, respectively, while the auxiliary circuit controls the cooling capacity of the battery through the third electronic expansion valve 6, achieving precise distribution. The auxiliary circuit uses a small-displacement compressor, reducing reliance on high-power compressors and saving manufacturing costs. A detection module monitors the circuit status in real time to avoid overload or leakage risks.

[0028] In some preferred embodiments, the system also includes a control module; the control module is used to adjust the opening of the first electronic expansion valve 4, the second electronic expansion valve 5 and the third electronic expansion valve 6 according to the refrigerant subcooling feedback from the first temperature and pressure detection module 7 and the second temperature and pressure detection module 8; the control module is also used to control the start and stop and speed of the first compressor 11 and the second compressor 12 according to the feedback from the first temperature detection module 9 and the second temperature detection module 10 and the battery inlet coolant temperature and the evaporation temperature of the evaporator 1.

[0029] In this embodiment, the function of the control module is defined. The compressor speed and start and stop are adjusted according to the feedback of the coolant temperature at the battery pack inlet and the evaporation temperature of the evaporator 1 obtained by the first temperature detection module 9 and the second temperature detection module 10; the openings of the first electronic expansion valve 4, the second electronic expansion valve 5 and the third electronic expansion valve 6 are adjusted according to the refrigerant supercooling feedback from the first temperature and pressure detection module 7 and the second temperature and pressure detection module 8; it should be noted that when the first electronic expansion valve 4 and the second electronic expansion valve 5 are opened at the same time, the control module controls the opening of the first electronic expansion valve 4 according to the supercooling feedback from the first temperature and pressure detection module 7, and controls the opening of the second electronic expansion valve 5 according to the battery inlet coolant temperature feedback from the first temperature detection module 9; the electronic expansion valve opening is adjusted in real time through temperature feedback to ensure that the cooling capacity is accurately matched with the demand and avoid refrigeration redundancy or insufficient; the system automatically shuts down when the pressure is abnormal to prevent equipment damage and refrigerant leakage, thereby improving system safety; the compressor speed and expansion valve opening are adjusted accordingly to reduce energy waste under low load conditions.

[0030] In the second aspect, the embodiment of the present application provides a dual compressor refrigeration control method for electric vehicles, referring to Figure 2 , Figure 2 This is a flow chart of the dual compressor refrigeration control method provided in the embodiment of the present application. Figure 2 As shown, a dual-compressor refrigeration control method for electric vehicles includes: S1. Real-time detection of vehicle status and acquisition of real-time cooling requirements for the passenger compartment and power battery. Vehicle status includes driving status, charging status, and other status. S2. According to the real-time vehicle status and cooling demand, the main refrigerant circuit is controlled to be on and off, and the cooling capacity of the evaporator 1 and the second heat exchanger 2 is controlled by the switching component, and the auxiliary refrigerant circuit is controlled to be on and off, and the cooling capacity of the first heat exchanger 3 is controlled by the switching component.

[0031] This approach, devised by the team, reveals that conventional systems are unable to flexibly switch operating modes based on vehicle status and lack differentiated control logic for high- and low-load scenarios. Therefore, a control method is proposed. Its core steps include: real-time detection of vehicle status (i.e., driving, charging, and other states); real-time monitoring of cooling demand; and control of the on / off state and cooling efficiency of the primary and auxiliary refrigeration circuits based on vehicle status and cooling demand. The operating mode of the primary and auxiliary circuits is dynamically selected based on vehicle status. For example, during fast charging, both the primary and auxiliary refrigerant circuits are activated, with the auxiliary circuit prioritized during driving. During low-load conditions, only the auxiliary refrigerant circuit is activated, avoiding redundant cooling output and reducing overall system energy consumption.

[0032] In some preferred embodiments, the system further includes a control module; the switching component includes a first electronic expansion valve 4 and a second electronic expansion valve 5 arranged in parallel; the main refrigerant circuit includes a first compressor 11, a first condenser 13, and a first temperature and pressure detection module 7 connected in sequence, and is connected to the evaporator 1 through the first electronic expansion valve 4 and to the second heat exchanger 2 through the second electronic expansion valve 5; the auxiliary refrigerant circuit includes a second compressor 12, a second condenser 14, and a second temperature and pressure detection module 8 connected in sequence, and is connected to the first heat exchanger 3 through the third electronic expansion valve 6; When the vehicle is in driving state and the passenger compartment does not require cooling, but the power battery does, the control module executes the first strategy, which includes the following: The first real-time temperature of the coolant at the battery inlet is obtained in real time; the control module only turns on the second compressor 12, and gradually increases the opening of the third electronic expansion valve 6 according to the first difference between the first real-time temperature and the first target temperature until the first difference is less than the first allowable threshold.

[0033] In this embodiment, conventional systems still require the operation of a large-displacement compressor even when battery demand is low, resulting in energy waste during low-load conditions and the inability of a single compressor to quickly respond to demand changes. Therefore, a first strategy is defined for driving conditions: when there is no passenger compartment demand and the battery requires cooling, only the second compressor 12 of the auxiliary refrigerant circuit is activated, and the cooling capacity is adjusted via the third electronic expansion valve 6. Based on the difference between the battery inlet coolant temperature and the target temperature, the opening of the third electronic expansion valve 6 is gradually increased until the temperature reaches the target. By activating only the small-displacement auxiliary circuit during low-load conditions, energy consumption is reduced. The gradual adjustment of the electronic expansion valve avoids temperature fluctuations caused by sudden changes in cooling capacity, improving control accuracy. Furthermore, the main compressor's operating time during low-load conditions is reduced, reducing mechanical wear.

[0034] In some preferred embodiments, when the vehicle is in a charging state and the passenger compartment has no cooling demand, but the power battery has cooling demand, the control module executes a second strategy, which includes the following: The control module executes the first strategy; if the opening of the third electronic expansion valve 6 is adjusted to the maximum and the first difference is still not less than the first allowable threshold, the control module turns on the first compressor 11, closes the first electronic expansion valve 4 and gradually increases the opening of the second electronic expansion valve 5 until the first difference is less than the first allowable threshold.

[0035] In this embodiment, a single circuit cannot handle extreme battery temperature rises, and conventional systems lack a fault-tolerant mechanism for incremental cooling. Therefore, the control strategy for the charging state is expanded to include a second strategy: If the auxiliary circuit cannot meet the battery cooling demand (i.e., the third electronic expansion valve 6 is fully opened and the temperature differential does not meet the required level), the first compressor 11 of the primary refrigerant circuit is activated. Since there is no passenger compartment cooling demand, the first electronic expansion valve 4 is closed, and the opening of the second electronic expansion valve 5 is gradually increased to supplement the battery cooling capacity. The coordinated operation of the primary and auxiliary refrigeration circuits effectively increases total cooling capacity and suppresses battery temperature rise. By activating the compressor and expansion valve in stages, system overload is avoided, and alarms are triggered in extreme situations to ensure safety. The primary circuit is activated only when necessary to avoid energy waste caused by prolonged operation of the high-power compressor.

[0036] In some preferred embodiments, when the vehicle is in driving state and there is a cooling demand for the passenger compartment and the power battery, the control module executes a third strategy, which includes the following: The first real-time temperature of the coolant at the battery inlet and the second real-time temperature of the evaporator 1 are obtained in real time; the control module starts the first compressor 11 and the second compressor 12 at the same time; the control module closes the second electronic expansion valve 5; the control module gradually increases the opening of the third electronic expansion valve 6 until a first difference between the first real-time temperature and the first target temperature is less than a first allowable threshold; the control module gradually increases the opening of the first electronic expansion valve 4 until a second difference between the second real-time temperature and the target evaporation temperature is less than a second allowable threshold.

[0037] In this embodiment, conventional systems struggle to balance cooling requirements when both the passenger compartment and the battery require cooling simultaneously, and running both compressors at full speed results in excessive noise. Therefore, a third strategy is defined for dual-requirement scenarios while driving: the compressors of both the primary and auxiliary refrigeration circuits are activated simultaneously. The second electronic expansion valve 5 is closed, halting cooling of the battery by the primary circuit, while the third electronic expansion valve 6 provides cooling to the battery pack 17. Cooling is provided to the passenger compartment via the first electronic expansion valve 4, with the opening gradually adjusted based on temperature feedback. Because battery cooling requirements are relatively low while driving, to reduce compressor noise, the first compressor 11 cools the passenger compartment, while the second compressor 12 cools the battery pack 17, enhancing driving comfort. The small displacement design of the auxiliary circuit reduces energy consumption when supplementing cooling capacity, while ensuring temperature control stability in dual-requirement scenarios.

[0038] In some preferred embodiments, when the vehicle is in a charging state and the passenger compartment and the power battery have cooling requirements, the control module executes a fourth strategy, which includes the following: The control module executes the third strategy and does not close the second electronic expansion valve 5; if the opening of the third electronic expansion valve 6 is adjusted to the maximum and the first difference is still not less than the first allowable threshold, the control module turns on the first compressor 11 and gradually increases the opening of the second electronic expansion valve 5 until the first difference is less than the first allowable threshold.

[0039] In this embodiment, a single circuit cannot meet the dual high demands of both the battery and the passenger compartment during charging, and traditional systems lack multi-level regulation capabilities in complex scenarios. Therefore, a fourth strategy for dual-demand scenarios during charging is developed: Building on the third strategy, the primary circuit maintains a cooling path for the battery, meaning the second electronic expansion valve 5 remains open. If the auxiliary circuit's cooling capacity is insufficient, the opening of the primary circuit's second electronic expansion valve 5 is gradually increased until the battery temperature meets the required standard. Because the battery load is high during charging and temperature control is difficult, both the primary and auxiliary refrigeration circuits provide cooling capacity for the battery simultaneously, increasing the total cooling capacity and ensuring temperature control requirements in extreme scenarios. While ensuring basic cooling for the passenger compartment, the remaining cooling capacity is flexibly allocated to the battery to achieve optimal resource allocation. The opening is gradually increased to avoid sudden changes in cooling capacity and enhance system stability.

[0040] In some preferred embodiments, when the vehicle is in other states, the control module executes a fifth control strategy according to the cooling demand, which includes the following: When there is no cooling demand for the passenger compartment and the power battery, it is determined whether the vehicle is currently in a cooling state. If so, the cooling is turned off; otherwise, the cooling state is maintained off; when there is a cooling demand for the passenger compartment and there is no cooling demand for the power battery, the second real-time temperature of the evaporator 1 is obtained in real time, and the control module only turns on the first compressor 11, closes the second electronic expansion valve 5, and gradually increases the opening of the first electronic expansion valve 4 until the difference between the second real-time temperature and the target evaporation temperature is less than the second allowable threshold.

[0041] This embodiment defines a fifth strategy for other states, such as parking and idle conditions: when there is no cooling demand, all circuits are shut down. When only the passenger compartment requires cooling, only the first compressor 11 of the main circuit is activated, and the cooling capacity is adjusted via the first electronic expansion valve 4. When there is no demand, the system is completely shut down, reducing energy consumption to zero and thus reducing unnecessary energy consumption. In single-demand scenarios, only essential components, such as the main circuit, are activated, avoiding inefficient operation of auxiliary circuits and reducing overall energy consumption.

[0042] In a third aspect, an embodiment of the present invention further provides a car, which includes the above-mentioned dual-compressor refrigeration system for electric vehicles, and determines the refrigeration requirements of the passenger compartment and the power battery as well as the vehicle status in real time when the vehicle is powered on.

[0043] The beneficial effects brought about by the present invention include: The embodiment of the present application provides a dual-compressor refrigeration system, control method, and vehicle for electric vehicles, wherein the auxiliary refrigerant circuit uses a small-displacement compressor. When the load is low, the small-displacement auxiliary refrigerant circuit is turned on to act on the first heat exchanger 3 of the battery coolant circuit, and the main refrigerant circuit is turned off, resulting in lower operating energy consumption and avoiding energy waste of the main refrigerant circuit. The system is also applicable to charging scenarios under high load conditions. At this time, it is only necessary to give priority to turning on the auxiliary refrigerant circuit. If it cannot meet the battery temperature suppression requirements, the main refrigerant circuit is turned on and the main refrigerant circuit is applied to the second heat exchanger 2 through a switching component, thereby meeting the requirement of suppressing the temperature rise of the power battery under high load conditions. At the same time, this adjustable dual-compressor mode can start and stop the main refrigerant circuit and the auxiliary refrigerant circuit accordingly according to other different vehicle states and cooling requirements. According to the adjustment of the switching component, the main refrigerant circuit can act on the evaporator 1 or the second heat exchanger 2 alone, or can act on the evaporator 1 and the second heat exchanger 2 simultaneously, thereby meeting more application scenarios and improving the compatibility of the system. The invention solves the problem in related technologies that the vehicle refrigeration system cannot simultaneously meet the cooling needs of the passenger compartment and the power battery under high load, and the energy waste caused by redundant cooling capacity distribution under low load conditions.

[0044] It should be noted that the battery cooling circuit also includes an expansion water tank 15 and an electronic water pump 16 , which can better achieve cooling of the battery pack 17 .

[0045] It should be noted that the serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0046] The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices. The terms "first", "second" and "third" are used to distinguish different objects, etc., and do not represent a sequence, nor do they limit the "first", "second" and "third" to different types.

[0047] In the description of the embodiments of this application, the words "exemplary," "for example," or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary," "for example," or "for example" in the embodiments of this application should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary," "for example," or "for example" is intended to present the relevant concepts in a concrete manner.

[0048] In the description of the embodiments of the present application, unless otherwise specified, “ / ” means or, for example, A / B can mean A or B; “and / or” in the text is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, “multiple” refers to two or more than two.

[0049] In some processes described in the embodiments of the present application, multiple operations or steps are included that appear in a specific order. However, it should be understood that these operations or steps may not be performed in the order in which they appear in the embodiments of the present application or may be performed in parallel. The sequence numbers of the operations are only used to distinguish between different operations, and the sequence numbers themselves do not represent any order of execution. In addition, these processes may include more or fewer operations, and these operations or steps may be performed in sequence or in parallel, and these operations or steps may be combined.

[0050] Through the description of the above embodiments, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus the necessary general hardware platform. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, or the part that contributes to the existing technology, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above and includes a number of instructions for enabling a terminal device to execute the methods described in each embodiment of this application.

[0051] The above are only preferred embodiments of the present application and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A dual compressor refrigeration system for electric vehicles, characterized in that: It includes: a battery coolant circuit, on which a second heat exchanger (2) and a first heat exchanger (3) are arranged in parallel; A passenger compartment cooling circuit having an evaporator (1) disposed thereon; a main refrigerant circuit connected to at least one of the evaporator (1) and the second heat exchanger (2) via a switching assembly; an auxiliary refrigerant circuit connected to the first heat exchanger (3); The displacement of the compressor in the auxiliary refrigerant circuit is smaller than the displacement of the compressor in the main refrigerant circuit.

2. The dual-compressor refrigeration system for electric vehicles according to claim 1, characterized in that: The battery coolant circuit is provided with a first temperature detection module (9); the passenger compartment cooling circuit is provided with a second temperature detection module (10); The switching assembly comprises a first electronic expansion valve (4) and a second electronic expansion valve (5); The main refrigerant circuit comprises a first compressor (11), a first condenser (13), and a first temperature and pressure detection module (7) connected in sequence, and is connected to the evaporator (1) via a first electronic expansion valve (4), and is connected to the second heat exchanger (2) via a second electronic expansion valve (5); The auxiliary refrigerant circuit comprises a second compressor (12), a second condenser (14), and a second temperature and pressure detection module (8) connected in sequence, and is connected to the first heat exchanger (3) via a third electronic expansion valve (6).

3. The dual-compressor refrigeration system for an electric vehicle according to claim 2, wherein: The system further includes a control module; The control module is used to adjust the openings of the first electronic expansion valve (4), the second electronic expansion valve (5) and the third electronic expansion valve (6) according to the refrigerant subcooling degree fed back by the first temperature and pressure detection module (7) and the second temperature and pressure detection module (8); The control module is further used to control the start and stop and rotation speed of the first compressor (11) and the second compressor (12) based on the battery inlet coolant temperature and the evaporation temperature of the evaporator (1) fed back by the first temperature detection module (9) and the second temperature detection module (10).

4. A dual-compressor refrigeration control method for electric vehicles, characterized in that: Providing a dual-compressor refrigeration system for an electric vehicle as claimed in claim 1; Real-time detection of vehicle status and acquisition of real-time cooling requirements for the passenger compartment and power battery; the vehicle status includes driving status, charging status, and other status; According to the real-time vehicle status and cooling demand, the main refrigerant circuit is controlled to be on and off, and the cooling capacity of the evaporator (1) or the second heat exchanger (2) is controlled through the switching component, and the auxiliary refrigerant circuit is controlled to be on and off, and the cooling capacity of the first heat exchanger (3) is controlled.

5. The dual-compressor refrigeration control method for electric vehicles according to claim 4, characterized in that: The system further includes a control module; The switching assembly comprises a first electronic expansion valve (4) and a second electronic expansion valve (5) arranged in parallel; The main refrigerant circuit comprises a first compressor (11), a first condenser (13), and a first temperature and pressure detection module (7) connected in sequence, and is connected to the evaporator (1) via a first electronic expansion valve (4), and is connected to the second heat exchanger (2) via a second electronic expansion valve (5); The auxiliary refrigerant circuit comprises a second compressor (12), a second condenser (14), and a second temperature and pressure detection module (8) connected in sequence, and is connected to the first heat exchanger (3) via a third electronic expansion valve (6); When the vehicle is in driving state and the passenger compartment has no cooling demand but the power battery has cooling demand, the control module executes the first strategy, which includes the following: Obtaining the first real-time temperature of the coolant at the battery inlet in real time; The control module only turns on the second compressor (12) and gradually increases the opening of the third electronic expansion valve (6) according to a first difference between the first real-time temperature and the first target temperature until the first difference is less than a first allowable threshold.

6. The dual-compressor refrigeration control method for electric vehicles according to claim 5, characterized in that: When the vehicle is in a charging state and the passenger compartment does not require cooling, but the power battery does require cooling, the control module executes a second strategy, which includes the following: The control module executes the first strategy; If the opening of the third electronic expansion valve (6) is adjusted to the maximum and the first difference is still not less than the first allowable threshold, the control module starts the first compressor (11), closes the first electronic expansion valve (4) and gradually increases the opening of the second electronic expansion valve (5) until the first difference is less than the first allowable threshold.

7. The dual-compressor refrigeration control method for electric vehicles according to claim 5, characterized in that: When the vehicle is in driving state and the passenger compartment and the power battery have cooling requirements, the control module executes the third strategy, which Includes the following: Real-time acquisition of a first real-time temperature of the coolant at the battery inlet and a second real-time temperature of the evaporator (1); The control module starts the first compressor (11) and the second compressor (12) simultaneously; The control module closes the second electronic expansion valve (5); The control module gradually increases the opening of the third electronic expansion valve (6) until a first difference between the first real-time temperature and the first target temperature is less than a first allowable threshold; The control module gradually increases the opening of the first electronic expansion valve (4) until a second difference between the second real-time temperature and the target evaporation temperature is less than a second allowable threshold.

8. The dual-compressor refrigeration control method for electric vehicles according to claim 7, characterized in that: When the vehicle is in charging state and the passenger compartment and the power battery require cooling, the control module executes the fourth strategy, which includes the following: The control module executes the third strategy and does not close the second electronic expansion valve (5); If the opening of the third electronic expansion valve (6) is adjusted to the maximum and the first difference is still not less than the first allowable threshold, the control module starts the first compressor (11) and gradually increases the opening of the second electronic expansion valve (5) until the first difference is less than the first allowable threshold.

9. The dual-compressor refrigeration control method for electric vehicles according to claim 5, characterized in that: When the vehicle is in other states, the control module performs the following steps based on the cooling demand: When there is no cooling demand for the passenger compartment and the power battery, it is determined whether the vehicle is currently in cooling state. If so, the cooling is turned off; otherwise, the cooling state is maintained off; When the passenger compartment has a cooling demand and the power battery has no cooling demand, the control module executes a fifth strategy, which includes obtaining a second real-time temperature of evaporation of the evaporator (1) in real time, the control module only starts the first compressor (11), closes the second electronic expansion valve (5), and gradually increases the opening of the first electronic expansion valve (4) until the difference between the second real-time temperature and the target evaporation temperature is less than a second allowable threshold.

10. A vehicle, characterized in that: It includes the dual-compressor refrigeration system for electric vehicles as described in claims 1-3.

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