Whole-vehicle thermal management system of pure electric vehicle and control method of whole-vehicle thermal management system

Abstract

The invention discloses a whole-vehicle thermal management system of a pure electric vehicle and a control method of the whole-vehicle thermal management system, and relates to the technical field of thermal management. Comprising a power battery system cooling loop, an electric drive system cooling loop and a passenger compartment heating loop, and the power battery system cooling loop and the electric drive system cooling loop are connected with a cooling liquid pipeline through a three-way electromagnetic valve and a second one-way valve; the passenger compartment heating loop and the electric driving system cooling loop are connected with a cooling liquid pipeline through a two-way electromagnetic valve; when a passenger compartment needs to be heated, cooling liquid is heated through heating of the water heater or heat absorption of the water condenser from a refrigerant pipeline of an air conditioning system, and when the cooling liquid passes through the warm air core body, the air blower blows heat into the passenger compartment. A power battery system cooling loop, an electric drive system cooling loop and a passenger compartment heating loop are designed in a coupling mode, and heat management energy consumption is reduced on the premise that the temperature requirements of all systems of the whole vehicle are met according to different whole vehicle using working conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermal management, and in particular relates to a thermal management system for a pure electric vehicle and a control method thereof. Background Art

[0002] At present, the thermal management system of pure electric vehicles on the market is generally composed of an electric drive cooling system, a battery thermal management system and an air-conditioning system. The water circulation loops of the three systems are mostly independently designed and unrelated to each other. The adjustment means are simple during the operation of the vehicle, and more vehicle electricity is required to cool or heat each system separately.

[0003] Existing technical solutions, such as Chinese patent CN103427137A, introduce a thermal management control system and control method for a pure electric vehicle. In the patent description, the electric drive cooling system, the battery thermal management system and the air-conditioning system each have an independent water circulation loop; the battery is cooled by an independent radiator or air compressor, and a heater is equipped to heat the battery; the electric drive system dissipates the coolant through a cooling fan and a radiator; the air-conditioning system dissipates the refrigerant through an air condenser.

[0004] For example, Chinese patent CN114714849A provides an electric vehicle thermal management system and an electric vehicle, which relates to the field of thermal management systems. The electric vehicle thermal management system includes a cooling and heating module, an HVAC module, a front-end module, a power battery, a first water pump, a second water pump, a third water pump, a first switch water valve, a second switch water valve, a third switch water valve, a first proportional water valve, an electronic drive unit, an expansion kettle, and a second proportional water valve. The refrigerant circuit can be heated, cooled, and dehumidified in the passenger compartment without changing the flow direction of the refrigerant, reducing the number of components of the refrigerant circuit, and making the system control simpler and more reliable. The electric vehicle includes the above electric vehicle thermal management system, thereby reducing the number of components of the refrigerant circuit, and making the system control simpler and more reliable.

[0005] However, as shown in the above-mentioned prior art, an independent radiator is used for cooling the battery system, and another radiator is used for cooling the electric drive system, resulting in a waste of resources. Or when driving at low temperatures, the waste heat of the electric drive system cannot be utilized by the battery system. Therefore, the present application designs a system operation strategy for different vehicle operating conditions, which can significantly improve the utilization of the thermal management system and reduce system energy consumption. Summary of the invention

[0006] The purpose of the present invention is to provide a thermal management system and control method for a pure electric vehicle. By designing a complete thermal management control method for different vehicle operating conditions, the thermal management energy consumption is reduced while ensuring the temperature requirements of each system of the vehicle, thereby solving the existing problems.

[0007] In order to solve the above technical problems, the present invention is achieved through the following technical solutions:

[0008] As a first aspect of the present invention, the present invention is a thermal management system for a pure electric vehicle, including a power battery system cooling circuit, an electric drive system cooling circuit, and a passenger compartment heating circuit, specifically:

[0009] The power battery system cooling circuit and the electric drive system cooling circuit are connected to the coolant pipeline via a three-way solenoid valve and a second one-way valve;

[0010] The passenger compartment heating circuit and the electric drive system cooling circuit are connected to the coolant pipeline via a two-way solenoid valve;

[0011] When the passenger compartment needs to be heated, the coolant is heated by the water heater or the water condenser absorbs heat from the refrigerant (high temperature) pipeline of the air conditioning system, and when the coolant passes through the heater core, the blower blows the heat into the passenger compartment.

[0012] Further, the power battery system cooling circuit is composed of a water pump 3, a water chiller, a water temperature sensor 3, a battery pack and a three-way solenoid valve connected by a coolant pipeline;

[0013] The electric drive system cooling circuit is composed of an on-board charger, a DCDC, a motor system, a second water temperature sensor, a second water pump and a radiator connected by a coolant pipeline, and the radiator is adjacent to the electronic fan;

[0014] The passenger compartment heating circuit is composed of a water condenser, a water heater, a water temperature sensor, a heater core, a one-way valve and a water pump connected by a coolant pipeline.

[0015] As a second aspect of the present invention, the present invention is a control method for a thermal management system of a pure electric vehicle, the control method is used to control the thermal management system of the pure electric vehicle as described in the first aspect, and the control method comprises the following steps:

[0016] The power battery system cooling circuit, the electric drive system cooling circuit, and the passenger compartment heating circuit are connected through a three-way solenoid valve, a one-way valve, and a two-way solenoid valve to couple the power battery system cooling circuit, the electric drive system cooling circuit, and the passenger compartment heating circuit;

[0017] Different control modes are used to control the operation of the thermal management system of pure electric vehicles according to different working conditions;

[0018] The control modes include mode 1 to mode 5, and the division methods and corresponding operation modes of modes 1 to 5 are respectively:

[0019] Mode 1: Under low temperature conditions, when the vehicle is in charging mode and the power battery has a heating demand, the water heater starts, the two-way solenoid valve opens, the three-way solenoid valve opens, water pump 1 and water pump 3 run, and water pump 2 stops;

[0020] Mode 2: Under low temperature conditions, when the vehicle is in charging mode and the power battery has cooling requirements, the two-way solenoid valve is closed, the three-way solenoid valve is opened, and water pumps 2 and 3 are running;

[0021] Mode 3: Under low temperature conditions, when the vehicle is in driving mode and the power battery needs to be heated, the two-way solenoid valve is closed, the three-way solenoid valve is opened, water pump 2 is stopped, and water pump 3 is running;

[0022] Mode 4: Under low temperature conditions, when the vehicle is in driving mode and there is no need to heat or cool the power battery, water pump 3 stops, the three-way solenoid valve is closed, and water pump 2 runs;

[0023] Mode 5: Under high temperature conditions, when the vehicle is in charging mode and the power battery has cooling requirements, the three-way solenoid valve is closed, the water pump is running, and the air conditioning system is running.

[0024] Furthermore, the operation method of Mode 1 includes:

[0025] After being heated, the coolant flows from the passenger compartment heating circuit to the power battery system cooling circuit to heat the battery pack;

[0026] When the water temperature Ta at the battery pack inlet (detected by the water temperature sensor 3) reaches T0, the power of the water heater is adjusted to stabilize the water temperature at the battery pack inlet at T0 to meet the heating requirements of the battery. T0 is a preset value.

[0027] Furthermore, the operation method of Mode 2 includes:

[0028] The coolant flows from the power battery system cooling circuit to the electric drive system cooling circuit, and after being cooled by the radiator, it flows back to the power battery system cooling circuit through the second one-way valve to cool the battery pack.

[0029] Furthermore, the operation method of Mode 3 includes:

[0030] The coolant flows from the electric drive system cooling circuit back to the power battery system cooling circuit through the one-way valve 2, bringing the heat generated by the DCDC and motor system to the battery pack;

[0031] The coolant does not pass through the radiator, thereby realizing the utilization of waste heat of the electric drive circuit.

[0032] Furthermore, when the mode 3 is working, if there is a heating demand in the passenger compartment, the air conditioning system heats the coolant through the water condenser and the water heater to heat the passenger compartment.

[0033] Furthermore, the operation method of Mode 4 includes:

[0034] The coolant circulates in the cooling circuit of the electric drive system, absorbs the heat from the DCDC and motor system, dissipates the heat through the radiator, and then flows into the cooling circuit of the electric drive system to cool the components.

[0035] Furthermore, in the mode 4, the two-way solenoid valve is closed, and if there is a heating demand in the passenger compartment, the air conditioning system heats the coolant through the water condenser and the water heater to provide heating for the passenger compartment.

[0036] Furthermore, the operation method of Mode 5 includes:

[0037] The low-temperature refrigerant of the air conditioning system exchanges heat with the coolant in the chiller. After the coolant cools down, it flows into the battery pack to absorb heat, flows out of the battery pack and then enters the chiller, repeating the cycle.

[0038] The two-way solenoid valve is opened, water pump one and water pump two are running, and the high-temperature refrigerant of the air-conditioning system dissipates heat through the water condenser, and then releases the heat to the coolant in the passenger compartment heating circuit. When the heated coolant flows through the heater core, the blower blows the heat into the passenger compartment; the high-temperature refrigerant of the air-conditioning system flows into the cooling circuit of the electric drive system and transfers the dissipated heat to the passenger compartment through the radiator; the on-board charger and DCDC use the radiator to transfer the dissipated heat to the passenger compartment.

[0039] The present invention has the following beneficial effects:

[0040] The present invention implements a coupling design through the power battery system cooling circuit, the electric drive system cooling circuit, and the passenger compartment heating circuit, and designs a complete thermal management control method for different vehicle operating conditions, thereby reducing the thermal management energy consumption while ensuring the temperature requirements of each system of the vehicle.

[0041] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0043] Figure 1 This is a schematic diagram of the vehicle thermal management system of the present invention;

[0044] Figure 2 This is a schematic diagram of the vehicle thermal management system mode 1 of the present invention;

[0045] Figure 3 This is a schematic diagram of mode 2 of the vehicle thermal management system of the present invention;

[0046] Figure 4 This is a schematic diagram of mode 3 of the vehicle thermal management system of the present invention;

[0047] Figure 5 This is a schematic diagram of mode 4 of the vehicle thermal management system of the present invention;

[0048] Figure 6 This is the principle diagram of Mode 5 of the vehicle thermal management system of the present invention. DETAILED DESCRIPTION

[0049] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0050] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0051] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0052] As used in the specification and appended claims of this application, the term "if" can be interpreted as "when" or "uponce" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "uponce it is determined" or "in response to determining" or "uponce [described condition or event] is detected" or "in response to detecting [described condition or event]", depending on the context.

[0053] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0054] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0055] Embodiment 1:

[0056] As a first embodiment of the present invention, the present invention is a thermal management system for a pure electric vehicle, such as Figure 1 As shown, it includes the power battery system cooling circuit, the electric drive system cooling circuit, and the passenger compartment heating circuit. Specifically:

[0057] The power battery system cooling circuit is composed of a water pump 3, a chiller, a water temperature sensor 3, a battery pack and a three-way solenoid valve connected by a coolant pipeline; the air conditioning system refrigerant (low temperature) pipeline enters the chiller and can generate heat exchange with the coolant;

[0058] The electric drive system cooling circuit is composed of an on-board charger, a DCDC (DCDC: a device on-board that converts a DC power supply of a certain voltage level into a DC power supply of another voltage level, such as converting the 400V voltage of a car power battery into a 14V low-voltage DC power output), a motor system, a second water temperature sensor, a second water pump and a radiator connected by a coolant pipeline, and the radiator is adjacent to the electronic fan;

[0059] The passenger compartment heating circuit is composed of a water condenser, a water heater, a water temperature sensor 1, a heater core, a one-way valve 1 and a water pump 1 connected by a coolant pipeline;

[0060] The power battery system cooling circuit and the electric drive system cooling circuit are connected to the coolant pipeline via a three-way solenoid valve and a second one-way valve;

[0061] The passenger compartment heating circuit and the electric drive system cooling circuit are connected to the coolant pipeline via a two-way solenoid valve;

[0062] When the passenger compartment needs to be heated, the coolant is heated by the water heater or the water condenser absorbs heat from the refrigerant (high temperature) pipeline of the air conditioning system, and when the coolant passes through the heater core, the blower blows the heat into the passenger compartment.

[0063] As an embodiment provided by the present invention, preferably, Figure 1 As shown, the passenger compartment heating circuit is composed of a water condenser, a water heater, a water temperature sensor 1, a heater core, a one-way valve 1 and a water pump 1 connected in sequence through a coolant pipeline, and the water condenser is connected to the A / C; the electric drive system cooling circuit is composed of an on-board charger, a DCDC, a motor system, a water temperature sensor 2, a water pump 2 and a radiator connected in sequence through a coolant pipeline, and the radiator is adjacent to the electronic fan; the power battery system cooling circuit is composed of a water pump 3, a chiller, a water temperature sensor 3, a battery pack and a three-way solenoid valve connected in sequence through a coolant pipeline, and the chiller is connected to the A / C, and one end of the three-way solenoid valve is connected to the water pump 3, one end is connected to the battery pack, and one end is connected to the connection end of the on-board charger and the radiator (the connection end of the one-way valve 1 and the water pump 1);

[0064] Among them, the one-way valve 1 is connected to the water pump 1 and then connected to the connection end of the vehicle charger and the radiator; the heater core is connected to the one-way valve 1 and then connected to the two-way solenoid valve through the coolant pipeline, and then connected to the connection end of the motor system and the water temperature sensor 2; the connection end of the motor system and the water temperature sensor 2 is connected to the one-way valve 2, and the other end of the one-way valve 2 is connected to the connection end of the water pump 3 and the three-way solenoid valve.

[0065] Embodiment 2:

[0066] As a second embodiment of the present invention, the present invention is a control method for a thermal management system of a pure electric vehicle, the control method is used to control the thermal management system of the pure electric vehicle as described in the first embodiment, and the control method comprises the following steps:

[0067] The power battery system cooling circuit, the electric drive system cooling circuit, and the passenger compartment heating circuit are connected by a three-way solenoid valve, a one-way valve, and a two-way solenoid valve to couple the power battery system cooling circuit, the electric drive system cooling circuit, and the passenger compartment heating circuit. The coupling method is as follows: Figure 1 As shown (the method of connecting the power battery system cooling circuit, the electric drive system cooling circuit, and the passenger compartment heating circuit through a three-way solenoid valve, a one-way valve, and a two-way solenoid valve is as in Example 1);

[0068] Different control modes are used to control the operation of the thermal management system of pure electric vehicles according to different working conditions;

[0069] The control modes include mode 1 to mode 5, and the division methods and corresponding operation modes of modes 1 to 5 are respectively:

[0070] Mode 1: Under low temperature conditions, when the vehicle is in charging mode and the power battery has a heating demand, the water heater starts, the two-way solenoid valve opens, the three-way solenoid valve opens, water pump 1 and water pump 3 run, and water pump 2 stops;

[0071] Mode 2: Under low temperature conditions, when the vehicle is in charging mode and the power battery has cooling requirements, the two-way solenoid valve is closed, the three-way solenoid valve is opened, and water pumps 2 and 3 are running;

[0072] Mode 3: Under low temperature conditions, when the vehicle is in driving mode and the power battery needs to be heated, the two-way solenoid valve is closed, the three-way solenoid valve is opened, water pump 2 is stopped, and water pump 3 is running;

[0073] Mode 4: Under low temperature conditions, when the vehicle is in driving mode and there is no need to heat or cool the power battery, water pump 3 stops, the three-way solenoid valve is closed, and water pump 2 runs;

[0074] Mode 5: Under high temperature conditions, when the vehicle is in charging mode and the power battery has cooling requirements, the three-way solenoid valve is closed, the water pump is running, and the air conditioning system is running.

[0075] As an embodiment provided by the present invention, preferably, Figure 2 As shown, the operation method of Mode 1 includes:

[0076] Under low temperature conditions, when the vehicle is in charging mode and the power battery needs to be heated, the water heater starts, the two-way solenoid valve opens, the three-way solenoid valve opens, water pump 1 and water pump 3 run, and water pump 2 stops. The heated coolant flows from the passenger compartment heating circuit to the power battery system cooling circuit to heat the battery pack;

[0077] When the water temperature Ta at the battery pack inlet (detected by the water temperature sensor 3) reaches T0, the power of the water heater is adjusted to stabilize the water temperature at the battery pack inlet near T0 to meet the heating requirements of the battery. T0 is a preset value.

[0078] As another embodiment provided by the present invention, preferably, if the system structure is changed, a heat exchanger is added between the power battery circuit and the passenger compartment circuit and connected through a pipeline. Then, the function of heating the power battery by using the water heater of the passenger compartment circuit can be realized without using a two-way solenoid valve and a three-way solenoid valve.

[0079] As an embodiment provided by the present invention, preferably, Figure 3 As shown, the operation method of Mode 2 includes:

[0080] Under low temperature conditions, the vehicle is in charging mode, and when the power battery has a cooling demand, the two-way solenoid valve is closed, the three-way solenoid valve is opened, water pump 2 and water pump 3 are running, and the coolant flows from the power battery system cooling circuit to the electric drive system cooling circuit. After the coolant is dissipated by the radiator, it flows back to the power battery system cooling circuit through the one-way valve 2 to cool the battery pack.

[0081] As another embodiment provided by the present invention, preferably, if the system structure is changed, a dedicated radiator and valve are added to the power battery circuit to achieve the same function.

[0082] As an embodiment provided by the present invention, preferably, Figure 4 As shown, the operation method of Mode 3 includes:

[0083] Under low temperature conditions, when the vehicle is in driving mode and the power battery needs to be heated, the two-way solenoid valve is closed, the three-way solenoid valve is opened, water pump 2 stops, and water pump 3 runs. The coolant flows back from the electric drive system cooling circuit to the power battery system cooling circuit through the one-way valve 2, bringing the heat generated by the DCDC and motor system to the battery pack;

[0084] The coolant does not pass through the radiator, thereby realizing the utilization of waste heat of the electric drive circuit.

[0085] As an embodiment provided by the present invention, preferably, when the mode 3 is working, if there is a heating demand in the passenger compartment, the air conditioning system heats the coolant through the water condenser and the water heater for heating the passenger compartment.

[0086] As an embodiment provided by the present invention, preferably, Figure 5 As shown, the operation method of Mode 4 includes:

[0087] Under low temperature conditions, when the vehicle is in driving mode and there is no need to heat or cool the power battery, water pump 3 stops, the three-way solenoid valve is closed, water pump 2 starts, and the coolant circulates in the cooling circuit of the electric drive system. After absorbing the heat from the DCDC and motor system, it is dissipated through the radiator and then flows into the cooling circuit of the electric drive system to cool the components.

[0088] As an embodiment provided by the present invention, preferably, in the mode 4, the two-way solenoid valve is closed, and if there is a heating demand in the passenger compartment, the air conditioning system heats the coolant through the water condenser and the water heater for heating the passenger compartment.

[0089] As an embodiment provided by the present invention, preferably, Figure 6 As shown, the operation method of Mode 5 includes:

[0090] Under high temperature conditions, when the vehicle is in charging mode and the power battery has a cooling demand, the three-way solenoid valve is closed, the water pump 3 is running, the air conditioning system is running, and the low-temperature refrigerant of the air conditioning system exchanges heat with the coolant in the chiller. After the coolant cools down, it flows into the battery pack to absorb heat, and then flows out of the battery pack and enters the chiller again, and the cycle repeats;

[0091] The two-way solenoid valve is opened, water pump 1 and water pump 2 are running, and the heating methods of the passenger compartment include:

[0092] Method 1: The high-temperature refrigerant of the air conditioning system dissipates heat through the water condenser and then releases the heat to the coolant in the passenger compartment heating circuit. When the heated coolant flows through the heater core, the blower blows the heat into the passenger compartment.

[0093] Method 2: The high-temperature refrigerant of the air conditioning system flows into the cooling circuit of the electric drive system and then transmits the heat to the passenger compartment through the radiator;

[0094] Method 3: The on-board charger and DCDC use a radiator to transfer the dissipated heat into the passenger compartment.

[0095] A thermal management system and control method for a pure electric vehicle is designed by coupling the cooling circuit of the power battery system, the cooling circuit of the electric drive system, and the heating circuit of the passenger compartment. A complete thermal management control method is designed for different vehicle operating conditions. Under the premise of ensuring the temperature requirements of each system of the vehicle, the thermal management energy consumption is reduced. Specifically:

[0096] After the various circuits of the vehicle thermal management system of the present invention are connected through a two-way solenoid valve, a three-way solenoid valve and a one-way valve, the coupling of the various circuits is achieved, and the operation is controlled in the manner of mode 1 to mode 5. Under the condition of meeting the vehicle thermal management requirements, the system utilization is improved and the system energy consumption is reduced.

[0097] Mode 1 uses the water heater in the passenger compartment circuit to heat the power battery in a low-temperature environment. In this way, the battery circuit does not need to be equipped with an additional PTC (PTC: a semiconductor heating ceramic. When the external temperature decreases, the resistance value of the PTC decreases, and the heat generation increases accordingly. Based on this principle, the PTC heater can automatically change the heat generation according to the change of ambient temperature. However, the main problem of PTC heating is that it consumes a lot of electricity, which in turn affects the range of electric vehicles. The advantage of the air conditioning system over PTC heating is that it is more energy-efficient, and its energy consumption is about 50% of the latter), saving the application of components;

[0098] Mode 2: In low temperature environment (e.g. 5℃~10℃), when the battery needs to be cooled due to high power charging, the radiator of the electric drive circuit is used to cool the battery circuit coolant, thereby achieving the effect of cooling the battery. In this way, there is no need to start the air conditioner, and the low-temperature refrigerant is used to cool the battery through the chiller, reducing the required energy consumption;

[0099] Mode 3: In low-temperature environments, when the battery needs to be heated while driving, the waste heat collected by the electric drive circuit is used to heat the battery, effectively utilizing the vehicle's waste heat.

[0100] In mode 5, in a high temperature environment, when the air conditioner is started to cool the battery, the heat generated by the air conditioning system is released into the coolant using the water condenser and dissipated through the radiator, effectively improving the heat dissipation efficiency of the air conditioner and reducing the load of the air conditioning compressor to a certain extent during cooling, thereby reducing the energy consumption of the air conditioner.

[0101] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0102] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A thermal management system for a pure electric vehicle, comprising a power battery system cooling circuit, an electric drive system cooling circuit, and a passenger compartment heating circuit, characterized in that: The power battery system cooling circuit and the electric drive system cooling circuit are connected to the coolant pipeline via a three-way solenoid valve and a second one-way valve; The passenger compartment heating circuit and the electric drive system cooling circuit are connected to the coolant pipeline via a two-way solenoid valve; When the passenger compartment needs to be heated, the coolant is heated by a water heater or by a water condenser absorbing heat from the refrigerant pipeline of the air conditioning system; when the coolant passes through the heater core, the blower blows the heat into the passenger compartment.

2. A thermal management system for a pure electric vehicle according to claim 1, characterized in that: The power battery system cooling circuit is composed of a water pump 3, a chiller, a water temperature sensor 3, a battery pack and a three-way solenoid valve connected by a coolant pipeline; The electric drive system cooling circuit is composed of an on-board charger, a DCDC, a motor system, a second water temperature sensor, a second water pump and a radiator connected by a coolant pipeline, and the radiator is adjacent to the electronic fan; The passenger compartment heating circuit is composed of a water condenser, a water heater, a water temperature sensor, a heater core, a one-way valve and a water pump connected by a coolant pipeline.

3. A control method for a thermal management system of a pure electric vehicle, characterized in that: The control method is used to control the thermal management system of the pure electric vehicle according to claim 2, and the control method comprises the following steps: The power battery system cooling circuit, the electric drive system cooling circuit, and the passenger compartment heating circuit are connected through a three-way solenoid valve, a one-way valve, and a two-way solenoid valve to couple the power battery system cooling circuit, the electric drive system cooling circuit, and the passenger compartment heating circuit; Different control modes are used to control the operation of the thermal management system of pure electric vehicles according to different working conditions; The control modes include mode 1 to mode 5, and the division methods and corresponding operation modes of modes 1 to 5 are respectively: Mode 1: Under low temperature conditions, when the vehicle is in charging mode and the power battery has a heating demand, the water heater starts, the two-way solenoid valve opens, the three-way solenoid valve opens, water pump 1 and water pump 3 run, and water pump 2 stops; Mode 2: Under low temperature conditions, when the vehicle is in charging mode and the power battery has cooling requirements, the two-way solenoid valve is closed, the three-way solenoid valve is opened, and water pumps 2 and 3 are running; Mode 3: Under low temperature conditions, when the vehicle is in driving mode and the power battery needs to be heated, the two-way solenoid valve is closed, the three-way solenoid valve is opened, water pump 2 is stopped, and water pump 3 is running; Mode 4: Under low temperature conditions, when the vehicle is in driving mode and there is no need to heat or cool the power battery, water pump 3 stops, the three-way solenoid valve is closed, and water pump 2 runs; Mode 5: Under high temperature conditions, when the vehicle is in charging mode and the power battery has cooling requirements, the three-way solenoid valve is closed, the water pump is running, and the air conditioning system is running.

4. The control method of a thermal management system of a pure electric vehicle according to claim 3, characterized in that: The operation method of Mode 1 includes: After being heated, the coolant flows from the passenger compartment heating circuit to the power battery system cooling circuit to heat the battery pack; When the water temperature Ta at the battery pack inlet reaches T0, adjust the power of the water heater to stabilize the water temperature at the battery pack inlet at T0; The water temperature Ta is detected by water temperature sensor 3, and T0 is a preset value.

5. The control method of a thermal management system of a pure electric vehicle according to claim 3, characterized in that: The operation method of Mode 2 includes: The coolant flows from the power battery system cooling circuit to the electric drive system cooling circuit, and after being cooled by the radiator, it flows back to the power battery system cooling circuit through the second one-way valve to cool the battery pack.

6. The control method of a thermal management system of a pure electric vehicle according to claim 3, characterized in that: The operation method of Mode 3 includes: The coolant flows from the electric drive system cooling circuit back to the power battery system cooling circuit through the one-way valve 2, bringing the heat generated by the DCDC and motor system to the battery pack; Wherein, the coolant does not pass through the radiator.

7. The control method of a thermal management system of a pure electric vehicle according to claim 6, characterized in that: When operating in the above-described mode 3, if there is a need for heating in the passenger compartment, the air conditioning system heats the coolant through the water condenser and the water heater to provide heating for the passenger compartment.

8. The control method of a thermal management system of a pure electric vehicle according to claim 3, characterized in that: The operation method of Mode 4 includes: The coolant circulates in the cooling circuit of the electric drive system, absorbs the heat from the DCDC and motor system, dissipates the heat through the radiator, and then flows into the cooling circuit of the electric drive system to cool the components.

9. The control method of a thermal management system of a pure electric vehicle according to claim 8, characterized in that: In the mode 4, the two-way solenoid valve is closed. If there is a heating demand in the passenger compartment, the air conditioning system heats the coolant through the water condenser and the water heater to heat the passenger compartment.

10. The control method of a thermal management system of a pure electric vehicle according to claim 3, characterized in that: The operation method of Mode 5 includes: The low-temperature refrigerant of the air conditioning system exchanges heat with the coolant in the chiller. After the coolant cools down, it flows into the battery pack to absorb heat, flows out of the battery pack and then enters the chiller, repeating the cycle. The two-way solenoid valve is open, pump 1 and pump 2 are running, and the heating methods for the passenger compartment include: Method 1: The high-temperature refrigerant of the air conditioning system dissipates heat through the water condenser and then releases the heat to the coolant in the passenger compartment heating circuit. When the heated coolant flows through the heater core, the blower blows the heat into the passenger compartment. Method 2: The high-temperature refrigerant of the air conditioning system flows into the cooling circuit of the electric drive system and then transmits the heat to the passenger compartment through the radiator; Method 3: The on-board charger and DCDC use a radiator to transfer the dissipated heat into the passenger compartment.

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