Electric motor coach thermal management system and method based on double secondary circuits

Abstract

The invention discloses an electric motor coach heat management system and method based on double secondary loops, the system comprises a heat pump system, a cold water system and a hot water system, the heat pump system is connected with the cold water system through an evaporator, and the heat pump system is connected with the hot water system through an air cooler; cold energy generated by an evaporator of the heat pump system is transmitted to the cold water system through the first secondary refrigerant loop to form a cold energy secondary loop; and heat generated by an air cooler of the heat pump system is transmitted to the hot water system through the second secondary refrigerant loop to form a heat secondary loop. Double secondary loops are adopted for independently transmitting cold energy and heat energy, the charging amount of a refrigerant of a heat pump system is reduced, safety is improved, energy interference is avoided, energy utilization is optimized through a seasonal control strategy, a heat pump is stopped for energy saving in spring and autumn, loads are reasonably distributed in summer, three-electricity waste heat is recycled in winter, and extra energy consumption is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermal management of electric buses, and in particular relates to a thermal management system and method for electric buses based on dual secondary circuits. Background Art

[0002] With the rapid development of the new energy vehicle industry, electric buses, as a crucial vehicle for public transportation and urban logistics, face increasing challenges in vehicle safety, energy efficiency, and range. Currently, electric bus thermal management systems must simultaneously meet the air conditioning requirements of the passenger compartment (cockpit) (cooling in summer and heating in winter) and the temperature control requirements of the three-electric system (battery, electronic control, and motor) to prevent overheating and performance degradation. Consequently, requirements for system integration and energy efficiency are increasing.

[0003] The existing thermal management system for electric buses has the following technical limitations:

[0004] First, some existing systems use traditional refrigerants (such as Freon or high-pressure refrigerants). These refrigerant circuits are often directly connected to the cabin air conditioning and three-electric cooling systems, resulting in large refrigerant charges and complex circuits. Refrigerant leaks not only affect system performance but can also pose safety risks due to the flammable and explosive nature of refrigerants (such as some synthetic refrigerants). Furthermore, complex circuit designs increase system size and make maintenance more difficult.

[0005] Second, existing systems often rely on single-circuit heat transfer (e.g., direct heat exchange between the refrigerant and the cabin or three-electric components) or a single mixed-circuit transmission system. This can easily lead to interference between cooling and heat transfer, resulting in significant energy loss. For example, during summer cooling, the three-electric system's heat dissipation and cabin cooling may share the same heat exchange path, resulting in excessive load on the heat pump system. During winter heating, relying solely on PTC (positive temperature coefficient) heaters or heat pumps to draw heat directly from the environment not only results in high energy consumption but can also lead to a sharp drop in heating efficiency due to low ambient temperatures, severely impacting range.

[0006] Third, the three-electric systems of electric buses (especially the motor and electronic control) will continuously generate waste heat during operation, but the existing systems often lack an efficient waste heat recovery mechanism: in spring and autumn or under low-load conditions, the waste heat is directly discharged into the environment, causing energy waste; when heating is needed in winter, this part of the waste heat cannot be effectively used to supplement the heat source, causing the heat pump system to consume more electricity, further exacerbating range anxiety. Summary of the Invention

[0007] In order to solve the above technical problems, the present invention proposes a thermal management system and method for an electric bus based on a dual secondary circuit.

[0008] In order to achieve the above object, the technical solution of the present invention is as follows:

[0009] In a first aspect, the present invention discloses a thermal management system for an electric bus based on a dual secondary circuit, comprising: a heat pump system, a chilled water system, and a hot water system. The heat pump system comprises: a compressor, an air cooler, an evaporator, and a refrigerant circulation circuit connecting the various components. The heat pump system is connected to the chilled water system via the evaporator, and the heat pump system is connected to the hot water system via the air cooler.

[0010] The cooling water system includes a cooling water pump, an air cooler, a battery liquid cooling plate, an electronic control and motor ATS cooling unit, and a first coolant loop connecting all components. The air cooler is used to cool the passenger compartment and cockpit in summer, the battery liquid cooling plate is used to cool the batteries, and the electronic control and motor ATS cooling unit is used to dissipate heat from the electronic control and motor.

[0011] The hot water system includes a hot water pump, floor radiators, an off-board heat exchanger, and a second refrigerant circuit connecting all components. The floor radiators are used to heat the passenger compartment and cockpit in winter, while the off-board heat exchanger is used to discharge the heat generated by the hot water system to the outside environment.

[0012] The cooling energy generated by the evaporator of the heat pump system is transferred to the chilled water system through the primary refrigerant circuit, forming a secondary cooling circuit;

[0013] The heat generated by the air cooler of the heat pump system is transferred to the hot water system through the second refrigerant loop, forming a secondary heat loop;

[0014] The cooling secondary circuit and the heating secondary circuit work independently to realize the distribution of cooling and heating respectively.

[0015] On the basis of the above technical solution, the following improvements can be made:

[0016] As a preferred solution, the outlet of the evaporator is connected to the inlet of the cold water pump via a pipeline, and the outlet of the cold water pump is connected to the inlet of the evaporator via a first cooling branch and a second cooling branch arranged in parallel;

[0017] The regulating valve R1 and the air cooler are installed in sequence along the flow direction of the brine on the first cooling branch;

[0018] The battery liquid cooling plate, electronic control and motor ATS cooling unit are installed in sequence along the flow direction of the refrigerant on the second cooling branch.

[0019] As a preferred solution, the cold water pump outlet is further connected to the electronic control and motor ATS cooling unit through a third cooling branch, and a regulating valve R2 is installed on the third cooling branch.

[0020] As a preferred solution, the outlet of the air cooler is connected to the inlet of the hot water pump via a pipeline, and the outlet of the hot water pump is connected to the inlet of the air cooler via a first heat branch and a second heat branch arranged in parallel;

[0021] The regulating valve R3 and the floor radiator are installed in sequence along the flow direction of the brine on the first heat branch;

[0022] The regulating valve R4 and the off-vehicle heat exchanger are sequentially installed on the second heat branch along the flow direction of the brine.

[0023] As a preferred solution, the heat pump system uses CO2 as the refrigerant.

[0024] As a preferred solution, the heat pump system includes: a CO2 refrigeration compressor, an air cooler, a regenerator, a drying filter, an electronic expansion valve, an evaporator, and a liquid storage device;

[0025] The CO2 refrigeration compressor, air cooler, regenerator, filter drier, electronic expansion valve, evaporator, and liquid receiver are connected through pipelines to form a CO2 refrigerant circulation loop.

[0026] In a second aspect, the present invention discloses a thermal management method for an electric bus based on a dual secondary circuit, which implements thermal management using any of the above-mentioned thermal management systems for electric buses, specifically controlling the operation of a heat pump system according to different seasons.

[0027] As a preferred solution, in spring and autumn, the heat pump system does not work, the regulating valve R1 is closed, the regulating valve R3 is closed, and the regulating valve R4 is opened;

[0028] The cold water pump of the cold water system is working, the electronic control and motor ATS cooling unit cools the electronic control and motor, the battery liquid cooling plate cools the battery, and the heat generated by the battery, electronic control and motor is discharged to the outside environment through the ATS heat exchanger of the electronic control and motor ATS cooling unit.

[0029] As a preferred solution, in summer, the heat pump system is cooling, the regulating valve R1 is open, the regulating valve R3 is closed, and the regulating valve R4 is open;

[0030] The cooling energy generated by the evaporator of the heat pump system is transferred to the chilled water system through the first refrigerant circuit;

[0031] The cooling water pump of the chilled water system is working, the air cooler cools the passenger compartment and cockpit in summer, the electronic control and motor ATS cooling unit cools the electronic control and motor, and the battery liquid cooling plate cools the battery;

[0032] The heat generated by the air cooler of the heat pump system is transferred to the hot water system through the second refrigerant circuit, and the off-vehicle heat exchanger discharges the heat generated by the heat pump system to the outside environment.

[0033] As a preferred solution, in winter, the heat pump system is heating, the outdoor heat exchanger is not running, the regulating valve R1 is closed, the regulating valve R3 is opened, and the regulating valve R4 is closed;

[0034] The cold water pump of the chilled water system is working, and the heat generated by the battery, electronic control and motor is transferred to the evaporator of the heat pump system through the first refrigerant loop, serving as the low-temperature heat source of the heat pump system;

[0035] The heat generated by the air cooler of the heat pump system is transferred to the hot water system through the second refrigerant circuit. The hot water pump of the hot water system works, and the floor radiator heats the passenger compartment and cockpit in winter.

[0036] The present invention discloses a thermal management system and method for an electric bus based on a dual secondary circuit, which has the following beneficial effects:

[0037] First, the dual secondary circuits independently transmit cooling and heat, reducing the refrigerant charge of the heat pump system, improving safety, and avoiding energy interference; the parallel branch and regulating valve design realizes on-demand distribution, improving response speed and energy utilization.

[0038] Second, CO2 is used as the refrigerant, which is non-flammable, non-explosive and environmentally friendly; the CO2 circuit is physically isolated from the refrigerant circuit, reducing the risk of leakage, lowering the charge volume and improving the safety of the entire vehicle.

[0039] Third, seasonal control strategies are used to optimize energy utilization: disabling heat pumps in spring and autumn to save energy, reasonably distributing loads in summer, and recovering waste heat from the three power plants in winter to reduce additional energy consumption.

[0040] Fourth, by reducing energy loss, recovering waste heat and efficient circulation, the power consumption of the thermal management system is reduced, indirectly improving battery life.

[0041] Fifth, the independent circuit design makes faults traceable, and the modular connection of subsystems facilitates maintenance and reduces the overall failure rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0043] Figure 1 This is one of the block diagrams of the electric bus thermal management system provided by an embodiment of the present invention.

[0044] Figure 2 This is the second block diagram of the electric bus thermal management system provided by an embodiment of the present invention.

[0045] Figure 3 This is the third block diagram of the electric bus thermal management system provided by an embodiment of the present invention.

[0046] Figure 4This is the fourth block diagram of the electric bus thermal management system provided in an embodiment of the present invention.

[0047] Figure 5 This is the fifth block diagram of the electric bus thermal management system provided in an embodiment of the present invention.

[0048] Figure 6 This is the sixth block diagram of the electric bus thermal management system provided in an embodiment of the present invention.

[0049] Among them: 1-heat pump system, 11-CO2 refrigeration compressor, 12-air cooler, 13-regenerator, 14-drying filter, 15-electronic expansion valve, 16-evaporator, 17-liquid reservoir, 2-cold water system, 21-cold water pump, 22-air cooler, 23-battery liquid cooling plate, 24-electronic control and motor ATS cooling unit, 3-hot water system, 31-hot water pump, 32-floor radiator, 33-outdoor heat exchanger. DETAILED DESCRIPTION

[0050] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0051] 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. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0052] The use of ordinal numbers "first," "second," "third," etc. to describe common objects merely indicates that different instances of similar objects are involved and is not intended to imply that the objects so described must have a given order in time, space, ranking, or in any other manner.

[0053] In addition, the expression of “comprising” an element is an “open” expression, which merely means that corresponding components or steps exist, and should not be interpreted as excluding additional components or steps.

[0054] In order to achieve the purpose of the present invention, some embodiments of a thermal management system for electric buses based on a dual secondary circuit are as follows: Figure 1 As shown, the thermal management system of the electric bus includes: a heat pump system 1, a cold water system 2 and a hot water system 3. The heat pump system 1 includes: a compressor, an air cooler 12, an evaporator 16 and a refrigerant circulation loop connecting the various components. The heat pump system 1 is connected to the cold water system 2 through the evaporator 16, and the heat pump system 1 is connected to the hot water system 3 through the air cooler 12.

[0055] The cooling water system 2 includes a cooling water pump 21, an air cooler 22, a battery liquid cooling plate 23, an electronic control and motor ATS cooling unit 24, and a first coolant loop connecting the various components. The air cooler 22 is used to cool the passenger compartment and cockpit in summer, the battery liquid cooling plate 23 is used to cool the batteries, and the electronic control and motor ATS cooling unit (including the ATS heat exchanger) is used to dissipate heat from the electronic control and motor.

[0056] The hot water system 3 includes: a hot water pump 31, a floor radiator 32, an outdoor heat exchanger 33, and a second refrigerant circuit connecting various components. The floor radiator 32 is used to heat the passenger compartment and cockpit in winter, and the outdoor heat exchanger 33 is used to discharge the heat generated by the hot water system 3 to the outdoor environment.

[0057] The cooling energy generated by the evaporator 16 of the heat pump system 1 is transferred to the cold water system 2 through the first refrigerant circuit, forming a secondary cooling energy circuit; the heat generated by the air cooler 12 of the heat pump system 1 is transferred to the hot water system 3 through the second refrigerant circuit, forming a secondary heat circuit.

[0058] The cooling secondary circuit and the heating secondary circuit work independently to realize the distribution of cooling and heating respectively.

[0059] The present invention uses dual secondary circuits to independently transmit cooling and heat, avoiding energy interference and achieving precise thermal management of the cabin air conditioning and the three-electric system (battery, electronic control, and motor are collectively referred to as the three-electric), thereby improving overall energy efficiency; the cold water and hot water systems are three specialized functions that adapt to different thermal requirements and enhance system adaptability.

[0060] The refrigerant circulation circuit, the first brine circuit, and the second brine circuit are all physically isolated from each other.

[0061] In order to further optimize the implementation effect of the present invention, in other embodiments, the remaining characteristic technologies are the same, except that the outlet of the evaporator 16 is connected to the inlet of the cold water pump 21 via a pipeline, and the outlet of the cold water pump 21 is connected to the inlet of the evaporator 16 via a first cooling branch and a second cooling branch arranged in parallel;

[0062] The regulating valve R1 and the cooling fan 22 are sequentially installed along the flow direction of the brine on the first cooling branch;

[0063] The battery liquid cooling plate 23 and the electronic control and motor ATS cooling unit are installed in sequence along the flow direction of the coolant on the second cooling branch.

[0064] By adopting the above embodiment, the parallel design of the cooling branches and the control of the regulating valve can distribute the cooling capacity to the cabin and the three-electric system as needed, reducing ineffective energy consumption; the flow path of the refrigerant is clear, improving the cooling capacity transfer efficiency and system response speed.

[0065] Furthermore, based on the above embodiment, the outlet of the air cooler 12 is connected to the inlet of the hot water pump 31 via a pipeline, and the outlet of the hot water pump 31 is connected to the inlet of the air cooler 12 via a first heat branch and a second heat branch arranged in parallel;

[0066] The regulating valve R3 and the floor radiator 32 are sequentially installed along the flow direction of the brine on the first heat branch;

[0067] The regulating valve R4 and the external heat exchanger 33 are sequentially installed on the second heat branch along the brine flow direction.

[0068] By adopting the above embodiment, the parallel design of heat branches and the control of regulating valves can realize the precise distribution of heat to the heating equipment or environment, achieve efficient heating in winter and rapid heat removal in summer, and optimize energy utilization.

[0069] Further, based on the above embodiment, Figure 2 As shown, the outlet of the cold water pump 21 is also connected to the electronic control and motor ATS cooling unit through the third cooling branch, and a regulating valve R2 is installed on the third cooling branch.

[0070] By adding a third cooling branch and regulating valve R2, the refrigerant flow through the electronic control and motor ATS cooling units can be independently adjusted in summer to precisely match their real-time cooling needs. When heat generation in the electronic control and motor increases dramatically, the R2 opening can be increased to boost cooling supply and prevent overheating due to insufficient cooling. When heat generation is low, the R2 opening can be reduced to minimize cooling waste, further optimizing cooling distribution efficiency, reducing the load on the heat pump system, and improving vehicle energy efficiency.

[0071] In order to further optimize the implementation effect of the present invention, in some other embodiments, the remaining characteristic technologies are the same, except that the heat pump system 1 uses CO2 as the refrigerant.

[0072] It uses CO2 refrigerant, which is non-flammable and non-explosive, highly safe, and more environmentally friendly, solving the safety and environmental problems of traditional refrigerants.

[0073] Furthermore, based on the above embodiment, the heat pump system 1 includes: a CO2 refrigeration compressor, an air cooler 12, a regenerator 13, a drying filter 14, an electronic expansion valve 15, an evaporator 16, and a liquid reservoir 17;

[0074] The CO2 refrigeration compressor, the air cooler 12, the regenerator 13, the filter drier 14, the electronic expansion valve 15, the evaporator 16, and the liquid storage tank 17 are connected through pipelines to form a CO2 refrigerant circulation loop.

[0075] By adopting the above embodiment, the compactness and operating efficiency of the heat pump system 1 are improved, and stable output of cooling / heating is ensured.

[0076] Furthermore, based on the above embodiment, the CO2 refrigerant circulation circuit of the heat pump system 1 is physically isolated from the first brine circuit of the chilled water system 2 and the second brine circuit of the hot water subsystem.

[0077] By adopting the above embodiment, the CO2 refrigerant circulation loop is physically isolated from the coolant loop, reducing the risk of refrigerant leakage and the charge amount, while avoiding direct contact between the refrigerant and other components, thereby improving system safety.

[0078] In other embodiments, in actual applications, since the electric bus thermal management system has some other functions (other functions do not involve the inventive point of the present invention), some pipelines, regulating valves and three-way valves will be added, such as Figure 3 As shown, no further details are given here.

[0079] In other embodiments, the present invention further discloses a thermal management method for an electric bus based on a dual secondary circuit, which implements thermal management using the electric bus thermal management system disclosed in any of the above embodiments, specifically controlling the operation of the heat pump system 1 according to different seasons.

[0080] The present invention controls the operation of the heat pump according to seasons, adapts to different environmental requirements, reduces ineffective energy consumption, and improves system energy efficiency.

[0081] like Figure 4 As shown, in spring and autumn (e.g., 5°C-25°C), the heat pump system 1 does not work, the regulating valve R1 is closed, the regulating valve R3 is closed, and the regulating valve R4 is opened;

[0082] The cold water pump of the cold water system 2 is working, the electronic control and motor ATS cooling unit 24 cools the electronic control and motor, the battery liquid cooling plate 23 cools the battery, and discharges the heat generated by the battery, electronic control and motor to the outside environment through the ATS heat exchanger of the electronic control and motor ATS cooling unit.

[0083] In spring and autumn, the heat pump is disabled and the heat generated by the battery, electronic control and motor is cooled by the ATS, significantly reducing energy consumption. The heat generated by the battery, electronic control and motor is discharged to the outside environment by the ATS heat exchanger, eliminating the need for the heat pump system 1 to operate, thus saving energy.

[0084] like Figure 5 As shown, in summer (e.g., above 25°C), the heat pump system 1 is cooling, the regulating valve R1 is open, the regulating valve R3 is closed, and the regulating valve R4 is open;

[0085] The cooling energy generated by the evaporator 16 of the heat pump system 1 is transferred to the chilled water system 2 via the first refrigerant circuit;

[0086] The cooling water pump of the cooling water system 2 is working, the air cooler 22 cools the passenger compartment and the cockpit in summer, the electric control and motor ATS cooling unit 24 cools the electric control and motor, and the battery liquid cooling plate 23 cools the battery;

[0087] The heat generated by the air cooler 12 of the heat pump system 1 is transferred to the hot water system 3 through the second coolant circuit, and the off-vehicle heat exchanger 33 discharges the heat generated by the heat pump system 1 to the environment outside the vehicle.

[0088] In summer, the heat pump provides cooling and exhaust heat simultaneously, keeping the cabin and the three-electric system cool while preventing heat pump overload and reducing energy consumption. Heat from the electronic control and motor is dissipated to the environment by the ATS cooling unit, saving energy without consuming the cooling capacity of the heat pump system.

[0089] like Figure 6 As shown, in winter (e.g., below 5°C), the heat pump system 1 is heating, the fan of the outdoor heat exchanger 33 is not running, the regulating valve R1 is closed, the regulating valve R3 is open, and the regulating valve R4 is closed;

[0090] The cold water pump 21 of the cold water system 2 is working, and the heat generated by the battery, electronic control and motor is transferred to the evaporator 16 of the heat pump system 1 through the first refrigerant loop, serving as the low-temperature heat source of the heat pump system 1;

[0091] The heat generated by the air cooler 12 of the heat pump system 1 is transferred to the hot water system 3 through the second refrigerant circuit. The hot water pump of the hot water system 3 works, and the floor radiator 32 heats the passenger compartment and the cockpit in winter.

[0092] In winter, waste heat from the three electricity sources is recovered as a heat source for heat pumps to reduce electricity consumption; targeted heating improves heating efficiency, reduces endurance loss, and saves energy.

[0093] The dual secondary circuit electric bus thermal management system and method of the present invention have the following beneficial effects:

[0094] First, improve system energy efficiency and response speed to achieve precise thermal management.

[0095] The "secondary cooling circuit" and "secondary heat circuit" disclosed in the present invention work independently, transferring cooling and heat respectively through the first refrigerant circuit and the second refrigerant circuit, thereby avoiding mutual interference between cooling and heat during the transmission process.

[0096] The present invention adopts a design of parallel branches and regulating valves (for example, the first cooling branch and the second cooling branch are controlled by regulating valve R1, and the first heating branch and the second heating branch are controlled by regulating valves R3 and R4). It can accurately adjust the refrigerant flow according to real-time needs, realize on-demand distribution of cooling / heating, and improve system response speed and energy utilization efficiency.

[0097] Second, enhance system safety and environmental protection.

[0098] The heat pump system 1 of the present invention uses CO2 as a refrigerant, and the CO2 refrigerant circulation loop is physically isolated from the coolant loops of the chilled water system 2 and the hot water system 3. As a natural refrigerant, CO2 is non-flammable and non-explosive, fundamentally eliminating the flammability and explosion risks and environmental issues associated with traditional refrigerants (such as Freon).

[0099] The physical isolation design ensures that the CO2 high-pressure refrigerant circulates only within the heat pump system 1, reducing direct contact with the vehicle cabin and three-electric components. The CO2 charge volume can also be significantly reduced (due to the independent and compact circuit), further reducing the risk of leakage and improving vehicle safety.

[0100] The refrigerant circulates only in an independent refrigerant circulation loop and is physically isolated from the coolant loop. There is no need to adapt to the huge pipelines of the cold water and hot water systems, which greatly reduces the charge volume, reduces the probability of leakage and the safety risks after leakage, and significantly improves system safety.

[0101] Third, optimize energy utilization and significantly reduce energy consumption.

[0102] In the spring and autumn, the heat pump system 1 of the present invention does not work, and only dissipates heat to the environment through the ATS cooling unit (reducing ineffective energy consumption); in the summer, cooling is supplied through the cooling circuit and waste heat is discharged through the heating circuit (avoiding overload of the heat pump); in the winter, waste heat from the battery, electronic control and motor is recovered (transferred to the evaporator 16 through the first refrigerant circuit) to replace part of the heat pump energy consumption.

[0103] The above strategy, combined with the independent energy transmission characteristics of the "dual secondary circuit", realizes the closed-loop management of "waste heat recovery - on-demand energy supply - redundant heat discharge", reduces the dependence on PTC auxiliary heating or additional heat extraction from heat pumps, and reduces the overall vehicle energy consumption.

[0104] Fourth, extend the range of electric buses.

[0105] Because the system accurately distributes energy through independent loops (reducing energy loss), recovers waste heat from the three electric systems (reducing heat pump energy consumption), and adopts a high-efficiency CO2 heat pump cycle (improving heating / cooling efficiency), it directly reduces the electrical energy consumption of the electric bus thermal management system.

[0106] The compact design of the physical isolation of the CO2 circuit and the refrigerant circuit makes the system small in size and light in weight, which indirectly reduces the energy consumption of the entire vehicle and ultimately achieves an increase in cruising range.

[0107] Fifth, improve system reliability and maintenance convenience.

[0108] The CO2 refrigerant circulation loop and the secondary refrigerant loop of the heat pump system 1 are completely independent. The subsystems (heat pump, cold water, hot water) are modularly connected through pipes and valves (such as parallel branches and regulating valves), making the system structure clear and the fault points traceable.

[0109] If a circuit (such as the cooling circuit) fails, only that circuit needs to be repaired, without affecting the basic functions of other circuits (such as the heating circuit), reducing the overall failure rate of the system, improving maintenance convenience and vehicle operation reliability.

[0110] In the description of the present invention, it should be understood that the terms "coaxial", "bottom", "one end", "top", "middle", "the other end", "upper", "one side", "top", "inside", "front", "center", "both ends", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0111] In the present invention, unless otherwise clearly stipulated and limited, the terms "install", "set", "connect", "fix", "screw" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0112] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which shall fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the appended claims and their equivalents.

[0113] The control method of the present invention is to control by manually starting and closing the switch. The wiring diagram of the power element and the provision of power supply are common knowledge in the field, and the present invention is mainly used to protect mechanical devices. Therefore, the control method and wiring layout are no longer explained in detail in the present invention.

Claims

1. The thermal management system of electric buses based on dual secondary circuits is characterized by: include: A heat pump system, a chilled water system, and a hot water system. The heat pump system includes a compressor, an air cooler, an evaporator, and a refrigerant circulation loop connecting the various components. The heat pump system is connected to the chilled water system via the evaporator, and the heat pump system is connected to the hot water system via the air cooler. The cooling water system includes: a cooling water pump, an air cooler, a battery liquid cooling plate, an electronic control and motor ATS cooling unit, and a first coolant circuit connecting the various components. The air cooler is used to cool the passenger compartment and cockpit in summer, the battery liquid cooling plate is used to cool the batteries, and the electronic control and motor ATS cooling unit is used to dissipate heat from the electronic control and motor. The hot water system includes: a hot water pump, a floor radiator, an off-vehicle heat exchanger, and a second refrigerant circuit connecting the various components. The floor radiator is used to heat the passenger compartment and the cockpit in winter, and the off-vehicle heat exchanger is used to discharge the heat generated by the hot water system to the outside environment. The cooling energy generated by the evaporator of the heat pump system is transferred to the chilled water system through the first refrigerant circuit to form a secondary cooling energy circuit; The heat generated by the air cooler of the heat pump system is transferred to the hot water system through the second refrigerant circuit to form a secondary heat circuit; The cooling secondary circuit and the heating secondary circuit work independently to realize the distribution of cooling and heating respectively.

2. The electric bus thermal management system according to claim 1, characterized in that: The outlet of the evaporator is connected to the inlet of the cold water pump via a pipeline, and the outlet of the cold water pump is connected to the inlet of the evaporator via a first cooling branch and a second cooling branch arranged in parallel; The regulating valve R1 and the air cooler are sequentially installed along the flow direction of the brine on the first cooling branch; The battery liquid cooling plate, electronic control and motor ATS cooling unit are installed in sequence along the flow direction of the coolant on the second cooling branch.

3. The electric bus thermal management system according to claim 2, characterized in that: The cold water pump outlet is also connected to the electronic control and motor ATS cooling unit through a third cooling branch, and a regulating valve R2 is installed on the third cooling branch.

4. The electric bus thermal management system according to claim 2 or 3, characterized in that: The outlet of the air cooler is connected to the inlet of the hot water pump via a pipeline, and the outlet of the hot water pump is connected to the inlet of the air cooler through a first heat branch and a second heat branch arranged in parallel; The regulating valve R3 and the floor radiator are sequentially installed on the first heat branch along the flow direction of the brine; The regulating valve R4 and the off-vehicle heat exchanger are sequentially installed on the second heat branch along the flow direction of the brine.

5. The electric bus thermal management system according to claim 1, characterized in that: The heat pump system uses CO2 as refrigerant.

6. The electric bus thermal management system according to claim 1, characterized in that: The heat pump system includes: a CO2 refrigeration compressor, an air cooler, a regenerator, a drying filter, an electronic expansion valve, an evaporator, and a liquid storage device; The CO2 refrigeration compressor, air cooler, regenerator, drying filter, electronic expansion valve, evaporator and liquid storage are connected through pipelines to form a CO2 refrigerant circulation loop.

7. The thermal management method of electric buses based on dual secondary circuits is characterized in that: Thermal management is achieved by using the thermal management system for an electric bus as described in any one of claims 4 to 6, specifically controlling the operation of the heat pump system according to different seasons.

8. The electric bus thermal management method according to claim 7, characterized in that: In spring and autumn, the heat pump system does not work, the regulating valve R1 is closed, the regulating valve R3 is closed, and the regulating valve R4 is opened; The cold water pump of the cold water system is working, the electronic control and motor ATS cooling unit cools the electronic control and motor, the battery liquid cooling plate cools the battery, and the heat generated by the battery, electronic control and motor is discharged to the outside environment through the ATS heat exchanger of the electronic control and motor ATS cooling unit.

9. The electric bus thermal management method according to claim 7, characterized in that: In summer, the heat pump system is cooling, the regulating valve R1 is open, the regulating valve R3 is closed, and the regulating valve R4 is open; The cooling energy generated by the evaporator of the heat pump system is transferred to the chilled water system through a first refrigerant circuit; The cooling water pump of the cooling water system is working, the air cooler is used to cool the passenger compartment and the cockpit in summer, the electronic control and motor ATS cooling unit is used to cool the electronic control and motor, and the battery liquid cooling plate is used to cool the battery; The heat generated by the air cooler of the heat pump system is transferred to the hot water system through the second coolant circuit, and the off-vehicle heat exchanger discharges the heat generated by the heat pump system to the outside environment.

10. The thermal management method for electric buses according to claim 7, characterized in that: In winter, the heat pump system is heating, the external heat exchanger is not running, the regulating valve R1 is closed, the regulating valve R3 is opened, and the regulating valve R4 is closed; When the cold water pump of the cold water system is working, the heat generated by the battery, electronic control and motor is transferred to the evaporator of the heat pump system through the first refrigerant circuit, serving as a low-temperature heat source for the heat pump system; The heat generated by the air cooler of the heat pump system is transferred to the hot water system through the second refrigerant circuit, the hot water pump of the hot water system works, and the floor radiator heats the passenger compartment and the cockpit in winter.

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