Power battery preheating control method and vehicle

Abstract

This application proposes a power battery preheating control method and a vehicle, belonging to the field of automotive control technology. The power battery preheating control is executed based on the vehicle's thermal management system. This method determines that preheating of the power battery is necessary when the current temperature of the power battery's circulating water circuit is less than or equal to the lower threshold of the operating temperature. At this point, refined preheating control is implemented based on the vehicle's current operating conditions. Specifically, if the vehicle is in a first operating condition, the first and second multi-way valves are controlled to open or close based on the current temperature of the power battery's circulating water circuit to preheat the power battery. If the vehicle is in a second operating condition, the first and second multi-way valves are controlled to open or close based on the current state of charge of the power battery to preheat it. This method allows the power battery preheating control to be adapted to the vehicle's operating conditions, improving the accuracy of preheating control.

Description

Technical Field

[0001] This application relates to the field of automotive control technology, and in particular to a power battery preheating control method and a vehicle. Background Technology

[0002] The power battery is the core component of range-extended vehicles. Its charging and discharging performance is greatly affected by temperature. Especially in low-temperature environments, the power battery cell temperature is low and the activity is reduced. At this time, its charging and discharging characteristics are poor. The charging process will be very inefficient, time-consuming, or even unable to charge at extremely low temperatures. The discharging process will not be able to release a large amount of power and will not be able to achieve the purpose of acceleration and overtaking as intended by the driver.

[0003] Currently, for range-extended hybrid vehicles, the preheating of the power battery is mainly achieved through a water heater (WPTC) or heat pump, or by the heat generated by the power battery itself. However, in low-temperature environments, the power battery itself has high internal resistance and low activity. Using the power battery to power the water heater (WPTC) for preheating is a single method and cannot be adapted to the vehicle's operating conditions, resulting in high overall energy consumption and a slow preheating rate for the power battery. Summary of the Invention

[0004] The main objective of this application is to propose a power battery preheating control method and a vehicle. The method aims to preheat the power battery by controlling the opening or closing of a first multi-way valve and a second multi-way valve based on the current temperature of the power battery's circulating water circuit or the current state of charge of the vehicle battery under different vehicle operating conditions. This allows the preheating control to adapt to the vehicle's operating conditions and improves the accuracy of preheating control.

[0005] To achieve the above objectives, a first aspect of this application proposes a power battery preheating control method, applied to a vehicle's thermal management system. The thermal management system includes an engine circulating water circuit, a motor circulating water circuit, a power battery circulating water circuit, a first multi-way valve, and a second multi-way valve. The engine circulating water circuit is connected to the motor circulating water circuit through the first multi-way valve to form a circulation loop, and the motor circulating water circuit is connected to the power battery circulating water circuit through the second multi-way valve to form a circulation loop. The power battery circulating water circuit includes a water heater for heating the power battery circulating water circuit.

[0006] The control method includes:

[0007] Detect whether the current temperature of the power battery circulation water circuit is less than or equal to the lower limit threshold of the operating temperature;

[0008] When the current temperature of the power battery circulating water circuit is less than or equal to the lower limit threshold, the current operating status of the vehicle is obtained;

[0009] When the vehicle is determined to be in the first operating condition based on the current operating status of the vehicle, the first multi-way valve and the second multi-way valve are controlled to open or close according to the current temperature of the power battery circulating water circuit in order to preheat the power battery. The first operating condition includes an engine speed of 0 or the range extender operating time being less than or equal to a preset time threshold.

[0010] When the vehicle is determined to be in a second operating condition based on its current operating status, the first multi-way valve and the second multi-way valve are controlled to open or close according to the current state of charge of the power battery in order to preheat the power battery. The second operating condition includes the range extender operating time being greater than the preset time threshold.

[0011] In this embodiment, the power battery preheating control is executed based on the vehicle's thermal management system. When the current temperature of the power battery's circulating water circuit is detected to be less than or equal to the lower threshold of the operating temperature, it can be determined that the power battery needs to be preheated. At this time, the preheating control of the power battery is refined in combination with the vehicle's current operating conditions. Specifically, if the vehicle's engine speed is 0, or the range extender's operating time is less than or equal to a preset time threshold, the first and second multi-way valves are controlled to open or close according to the current temperature of the power battery's circulating water circuit, thereby preheating the power battery. Conversely, if the vehicle's range extender's operating time is greater than the preset time threshold, the first and second multi-way valves are controlled to open or close according to the power battery's current state of charge, thereby preheating the power battery. This allows the power battery preheating control to be adapted to the vehicle's operating conditions, improving the accuracy of preheating control.

[0012] In one embodiment of this application, controlling the first multi-way valve and the second multi-way valve to open or close based on the current temperature of the power battery circulating water circuit to preheat the power battery includes:

[0013] When the current temperature of the power battery circulating water circuit is less than or equal to the lower limit threshold but greater than the first temperature threshold, the power battery is preheated according to the first preheating mode. The first preheating mode includes controlling the first multi-way valve and the second multi-way valve to be disconnected, and controlling the range extender to supply power to the water heater so that the water heater can heat.

[0014] When the current temperature of the power battery circulating water circuit is less than or equal to the first temperature threshold but greater than the second temperature threshold, the power battery is preheated according to the second preheating mode. The second preheating mode includes controlling the first multi-way valve to open, the second multi-way valve to open, and controlling the range extender to supply power to the water heater so that the water heater can heat.

[0015] When the current temperature of the power battery circulating water circuit is less than or equal to the second temperature threshold, the power battery is preheated according to the third preheating mode. The third preheating mode includes controlling both the first multi-way valve and the second multi-way valve to be open, and controlling the range extender to supply power to the water heater so that the water heater can heat.

[0016] In this embodiment, when the vehicle is in the first operating condition, different preheating controls are implemented based on the current temperature of the power battery circulating water circuit. Specifically, when the current temperature of the power battery circulating water circuit is less than or equal to the lower threshold but greater than the first temperature threshold, it indicates that the power battery temperature is low. In this case, it is only necessary to control the range extender to supply power to the water heater to preheat the power battery. That is, it is necessary to control both the first and second multi-way valves to be disconnected. However, when the current temperature of the power battery circulating water circuit is less than or equal to the first temperature threshold but greater than the second temperature threshold, it indicates that the power battery temperature is low. In this case, considering that only controlling the range extender to supply power to the water heater to preheat the power battery results in a slow preheating rate and untimely preheating response, this embodiment further controls the first multi-way valve to be disconnected and the second multi-way valve to be open, so that the medium-temperature water in the motor circulating water circuit can flow to the power battery circulating water circuit to further heat the power battery, thereby improving the preheating rate. When the current temperature of the power battery circulating water circuit is less than or equal to the second temperature threshold, it indicates that the temperature of the power battery is extremely low. At this time, in order to further improve the preheating rate, both the first multi-way valve and the second multi-way valve can be controlled to be open, so that the high-temperature water in the engine circulating water circuit and the medium-temperature water in the motor circulating water circuit can flow to the power battery circulating water circuit to further heat the power battery.

[0017] In one embodiment of this application, after preheating the power battery according to the first preheating mode, the method further includes:

[0018] Detect the rate of temperature change in the power battery's circulating water circuit;

[0019] When the rate of temperature change is less than the lower limit of the preset rate of temperature change, the power battery is preheated according to the second preheating mode.

[0020] When the rate of temperature change exceeds the upper limit of the preset rate of temperature change, the system enters a fault mode and issues a fault alarm.

[0021] When the rate of temperature change is between the lower limit and the upper limit of the preset rate of temperature change, the power battery is preheated according to the first preheating mode until the current temperature of the power battery circulation water circuit exceeds the lower limit threshold.

[0022] In this embodiment, considering that preheating the power battery according to the first preheating mode cannot meet the preheating response requirements, the temperature change rate of the power battery circulation water circuit is further detected after preheating the power battery according to the first preheating mode. When the temperature change rate is less than the lower limit of the preset temperature change rate, it indicates that the temperature rise is slow and cannot meet the preheating response requirements under the first preheating mode. At this time, it is necessary to switch to the second preheating mode to preheat the power battery. When the temperature change rate is greater than the upper limit of the preset temperature change rate, it indicates that the temperature is rising rapidly, which may be due to water leakage, blockage of the power battery circulation water circuit, or malfunction of the water heater. Therefore, a fault mode is entered and a fault alarm is issued. When the temperature change rate is between the lower and upper limits of the preset temperature change rate, it indicates that the current heat supply is reasonable and the temperature rise meets the standard. Therefore, the power battery can be preheated according to the first preheating mode until the current temperature of the power battery circulation water circuit exceeds the lower threshold.

[0023] In one embodiment of this application, detecting the temperature change rate of the power battery circulating water circuit includes:

[0024] The current temperature of the power battery circulation water circuit is obtained at preset time intervals;

[0025] The rate of temperature change of the power battery circulation water circuit is calculated based on the current temperature of at least two of the power battery circulation water circuits.

[0026] In this embodiment, the current temperature of the power battery circulating water circuit is obtained at preset intervals. Based on the current temperatures of at least two power battery circulating water circuits, the temperature change rate of the power battery circulating water circuit can be calculated. This allows for further judgment on the temperature change rate of the power battery circulating water circuit to determine the corresponding preheating mode for preheating the power battery.

[0027] In one embodiment of this application, after switching to the second preheating mode to preheat the power battery when the temperature change rate is less than a preset lower limit value, the method further includes:

[0028] The rate of temperature change in the power battery's circulating water circuit was detected again.

[0029] When the rate of temperature change is less than the lower limit of the preset rate of temperature change, the power battery is preheated according to the third preheating mode until the current temperature of the power battery circulation water circuit exceeds the lower limit threshold.

[0030] When the rate of temperature change is between the lower limit and the upper limit of the preset rate of temperature change, the power battery is preheated according to the second preheating mode until the current temperature of the power battery circulation water circuit exceeds the lower limit threshold.

[0031] In this embodiment, considering that switching to the second preheating mode for preheating the power battery may not yet meet the preheating response requirements, the temperature change rate of the power battery's circulating water circuit is detected again after switching to the second preheating mode. If the temperature change rate is less than the preset lower limit, it indicates that the temperature rise is still slow and cannot meet the preheating response requirements under the second preheating mode. In this case, it is necessary to switch to the third preheating mode for preheating the power battery. If the temperature change rate is between the preset lower and upper limits, it indicates that the current heat supply is reasonable and the temperature rise meets the standard. Therefore, the second preheating mode can be maintained until the current temperature of the power battery's circulating water circuit exceeds the lower threshold.

[0032] In one embodiment of this application, when the current temperature of the power battery circulating water circuit is less than or equal to the first temperature threshold but greater than the second temperature threshold, the method further includes:

[0033] Detect whether the temperature of the motor circulating water circuit is greater than or equal to the lower temperature threshold of the water flowing from the motor circulating water circuit to the power battery circulating water circuit;

[0034] When the temperature of the motor circulating water circuit is lower than the lower limit threshold of the temperature of the motor circulating water circuit flowing to the power battery circulating water circuit, the power battery is preheated according to the first preheating mode;

[0035] When the temperature of the motor circulating water circuit is greater than or equal to the lower limit threshold of the temperature at which the motor circulating water circuit flows to the power battery circulating water circuit, the power battery is preheated according to the second preheating mode until the current temperature of the power battery circulating water circuit exceeds the lower limit threshold.

[0036] In this embodiment, when the current temperature of the power battery circulating water circuit is less than or equal to a first temperature threshold but greater than a second temperature threshold, it indicates that the power battery temperature is low. In this case, it is necessary to first detect whether the temperature of the motor circulating water circuit is greater than or equal to the lower limit threshold of the temperature through which the motor circulating water flows to the power battery circulating water circuit. If it is greater than or equal to, the power battery can be preheated according to the second preheating mode until the current temperature of the power battery circulating water circuit exceeds the lower limit threshold. If it is not greater than or equal to (i.e., less than), the power battery can only be preheated according to the first preheating mode.

[0037] In one embodiment of this application, when the current temperature of the power battery circulating water circuit is less than or equal to the second temperature threshold, the method further includes:

[0038] The temperature of the engine circulating water circuit is detected to be greater than or equal to the lower limit threshold of the temperature of the engine circulating water circuit flowing to the motor circulating water circuit, and the temperature of the motor circulating water circuit is detected to be greater than or equal to the lower limit threshold of the temperature of the motor circulating water circuit flowing to the power battery circulating water circuit.

[0039] When the temperature of the engine circulating water circuit is lower than the lower limit threshold of the temperature of the engine circulating water circuit flowing to the motor circulating water circuit, and the temperature of the motor circulating water circuit is lower than the lower limit threshold of the temperature of the motor circulating water circuit flowing to the power battery circulating water circuit, the power battery is preheated according to the first preheating mode.

[0040] When the temperature of the engine circulating water circuit is lower than the lower limit threshold of the temperature of the engine circulating water circuit flowing to the motor circulating water circuit, but the temperature of the motor circulating water circuit is greater than or equal to the lower limit threshold of the temperature of the temperature of the motor circulating water circuit flowing to the power battery circulating water circuit, the power battery is preheated according to the second preheating mode;

[0041] When the temperature of the engine circulating water circuit is greater than or equal to the lower limit threshold of the temperature of the engine circulating water circuit flowing to the motor circulating water circuit, but the temperature of the motor circulating water circuit is less than the lower limit threshold of the temperature of the motor circulating water circuit flowing to the power battery circulating water circuit, the first multi-way valve is controlled to open and the second multi-way valve is controlled to close until the temperature of the motor circulating water circuit is greater than or equal to the lower limit threshold of the temperature of the motor circulating water circuit flowing to the power battery circulating water circuit.

[0042] When the temperature of the motor circulating water circuit is greater than or equal to the lower limit threshold of the temperature of the motor circulating water circuit flowing to the power battery circulating water circuit, and the temperature of the engine circulating water circuit is greater than or equal to the lower limit threshold of the temperature of the engine circulating water circuit flowing to the motor circulating water circuit, the power battery is preheated according to the third preheating mode until the current temperature of the power battery circulating water circuit exceeds the lower limit threshold.

[0043] In this embodiment, when the current temperature of the power battery circulating water circuit is less than or equal to the second temperature threshold, it indicates that the power battery temperature is extremely low. In this case, it is necessary to first detect whether the temperature of the engine circulating water circuit is greater than or equal to the lower limit threshold of the temperature flowing from the engine circulating water circuit to the motor circulating water circuit, and whether the temperature of the motor circulating water circuit is greater than or equal to the lower limit threshold of the temperature flowing from the motor circulating water circuit to the power battery circulating water circuit. If the temperature of both the engine and motor circulating water circuits is greater than or equal to the lower limit threshold of the temperature flowing from the motor circulating water circuit to the power battery circulating water circuit, then the power battery can be preheated according to the third preheating mode until the current temperature of the power battery circulating water circuit exceeds the lower limit threshold. However, if the temperature of both the engine and motor circulating water circuits is less than the lower limit threshold of the temperature flowing from the engine circulating water circuit to the motor circulating water circuit, then the power battery can only be preheated according to the first preheating mode. If the temperature of the engine circulating water circuit is lower than the lower limit threshold of the temperature range from the engine circulating water circuit to the motor circulating water circuit, but the temperature of the motor circulating water circuit is greater than or equal to the lower limit threshold of the temperature range from the motor circulating water circuit to the power battery circulating water circuit, then the power battery can be preheated according to the second preheating mode. If the temperature of the engine circulating water circuit is greater than or equal to the lower limit threshold of the temperature range from the engine circulating water circuit to the motor circulating water circuit, but the temperature of the motor circulating water circuit is lower than the lower limit threshold of the temperature range from the motor circulating water circuit to the power battery circulating water circuit, then the first multi-way valve is opened and the second multi-way valve is closed, allowing the high-temperature water in the engine circulating water circuit to flow into the motor circulating water circuit. This allows the temperature of the motor circulating water circuit to gradually rise above the lower limit threshold of the temperature range from the motor circulating water circuit to the power battery circulating water circuit, and then the power battery can be preheated according to the third preheating mode until the current temperature of the power battery circulating water circuit exceeds the lower limit threshold.

[0044] In one embodiment of this application, controlling the first multi-way valve and the second multi-way valve to open or close according to the current state of charge of the power battery to preheat the power battery includes:

[0045] When the current state of charge of the power battery is greater than the limit of the state of charge threshold of the extreme depletion but less than or equal to the state of charge threshold of the allowable pure electric operation, the power battery is preheated according to the second preheating mode. The second preheating mode includes controlling the first multi-way valve to open, the second multi-way valve to open, and controlling the range extender to supply power to the water heater so that the water heater can heat.

[0046] When the current state of charge of the power battery is greater than the charge state threshold that allows pure electric operation, the system detects whether the vehicle is in fuel priority mode or electric priority mode.

[0047] When the vehicle is in the fuel priority mode, the power battery is preheated according to the second preheating mode;

[0048] When the vehicle is in the power priority mode, the power battery is preheated according to the third preheating mode. The third preheating mode includes controlling both the first multi-way valve and the second multi-way valve to be open, and controlling the range extender to supply power to the water heater so that the water heater can heat.

[0049] In this embodiment, when the vehicle is in the second operating condition, different preheating controls can be implemented based on the current state of charge (SOC) of the power battery. Specifically, when the current SOC of the power battery is greater than the SOC threshold for extreme depletion but less than or equal to the SOC threshold for allowing pure electric operation, the power battery is preheated according to the second preheating mode. When the current SOC of the power battery is greater than the SOC threshold for allowing pure electric operation, it indicates that the vehicle can operate purely on electric power. In this case, it can be further detected whether the vehicle is in a fuel-priority mode or an electric-priority mode. Therefore, when the vehicle is detected to be in a fuel-priority mode, the power battery is controlled to be preheated according to the second preheating mode; when the vehicle is detected to be in an electric-priority mode, the power battery is controlled to be preheated according to the third preheating mode. Thus, by adapting the preheating control of the power battery to the vehicle's operating conditions, it is possible to avoid charging the battery at low temperatures while also improving the accuracy of preheating control.

[0050] In one embodiment of this application, after preheating the power battery according to the second preheating mode, the method further includes:

[0051] Detect the rate of temperature change in the power battery's circulating water circuit;

[0052] When the rate of temperature change is less than the lower limit of the preset rate of temperature change, the power battery is preheated according to the third preheating mode until the current temperature of the power battery circulation water circuit exceeds the lower limit threshold.

[0053] When the rate of temperature change exceeds the upper limit of the preset rate of temperature change, the system enters a fault mode and issues a fault alarm.

[0054] When the rate of temperature change is between the lower limit and the upper limit of the preset rate of temperature change, the power battery is preheated according to the second preheating mode until the current temperature of the power battery circulation water circuit exceeds the lower limit threshold.

[0055] In this embodiment, when the vehicle is in the second operating condition, considering that preheating the power battery according to the second preheating mode cannot meet the preheating response requirements, the temperature change rate of the power battery circulating water circuit is further detected after preheating the power battery according to the second preheating mode. When the temperature change rate is less than the lower limit of the preset temperature change rate, it indicates that the temperature rise is slow and cannot meet the preheating response requirements under the second preheating mode. At this time, it is necessary to switch to the third preheating mode to preheat the power battery. When the temperature change rate is greater than the upper limit of the preset temperature change rate, it indicates that the temperature is rising rapidly, which may be due to water leakage, blockage of the power battery circulating water circuit, or malfunction of the water heater. Therefore, a fault mode is entered and a fault alarm is issued. When the temperature change rate is between the lower and upper limits of the preset temperature change rate, it indicates that the current heat supply is reasonable and the temperature rise meets the standard. Therefore, the power battery can be preheated according to the second preheating mode until the current temperature of the power battery circulating water circuit exceeds the lower threshold.

[0056] To achieve the above objectives, a second aspect of this application provides a vehicle, the vehicle including a thermal management system, the thermal management system including an engine circulating water circuit, a motor circulating water circuit, a power battery circulating water circuit, a first multi-way valve and a second multi-way valve, wherein the engine circulating water circuit is connected to the motor circulating water circuit through the first multi-way valve to form a circulation loop, the motor circulating water circuit is connected to the power battery circulating water circuit through the second multi-way valve to form a circulation loop, and the power battery circulating water circuit includes a water heater for heating the power battery circulating water circuit;

[0057] The vehicle is used to execute the power battery preheating control method provided in any embodiment of this application.

[0058] In this embodiment of the application, by executing the power battery preheating control method provided in any embodiment of the application, the vehicle can adapt the preheating control to the vehicle's operating conditions, thereby improving the accuracy of the preheating control. Attached Figure Description

[0059] Figure 1 This is a schematic diagram of the thermal management system of the range-extended electric vehicle provided in the embodiments of this application;

[0060] Figure 2 This is a schematic diagram of the structure of the first multi-way valve provided in the embodiments of this application;

[0061] Figure 3 This is a flowchart of the power battery preheating control method provided in the embodiments of this application;

[0062] Figure 4This is a flowchart of the steps provided in this application embodiment to control the opening or closing of the first multi-way valve and the second multi-way valve according to the current temperature of the power battery circulation water circuit in order to preheat the power battery;

[0063] Figure 5 This is a flowchart of the steps performed after preheating the power battery according to the first preheating mode, provided in an embodiment of this application.

[0064] Figure 6 This is a flowchart of the steps performed after switching to the second preheating mode to preheat the power battery when the temperature change rate is less than the lower limit of the preset temperature change rate, according to an embodiment of this application.

[0065] Figure 7 This is a flowchart of the steps to be performed when the current temperature of the power battery circulating water circuit is less than or equal to a first temperature threshold but greater than a second temperature threshold, as provided in an embodiment of this application.

[0066] Figure 8 This is a flowchart of the steps to be performed when the current temperature of the power battery's circulating water circuit is less than or equal to a second temperature threshold, as provided in an embodiment of this application.

[0067] Figure 9 This is a flowchart of the steps provided in this application embodiment to control the first multi-way valve and the second multi-way valve to open or close according to the current state of charge of the power battery in order to preheat the power battery;

[0068] Figure 10 This is a flowchart of the steps performed after preheating the power battery according to the second preheating mode, as provided in the embodiments of this application.

[0069] Figure label:

[0070] Engine circulating water circuit -1; Motor circulating water circuit -2; Power battery circulating water circuit -3; First multi-way valve -4; Second multi-way valve -5; First outlet -41; Second outlet -42; First inlet -43; Second inlet -44; First water pump -11; Engine -12; Thermostat -13; First radiator -14; Water filling container -15; Second water pump -21; Generator -22; Generator controller -23; Second radiator -24; Drive motor -25; Drive motor controller -26; Third water pump -31; Power battery -32; Water heater -33; Refrigerant heat exchanger -34; Liquid receiver -35; Condenser -36; Compressor -37. Detailed Implementation

[0071] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0072] It should be noted that although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device or the order in the flowchart. The terms "first," "second," etc., in the specification, claims, and the aforementioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0073] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0074] In recent years, research on energy-saving and new energy vehicle technologies has been extensive, aiming to significantly improve fuel economy and reduce emissions. These technologies primarily include hybrid power technology, diesel engine technology, natural gas fuel technology, flexible fuel technology, pure electric technology, and fuel cell technology. All these technologies have made significant progress, particularly hybrid power technology, which was among the first to achieve large-scale industrialization. Hybrid power technology possesses numerous advantages not found in other technologies, improving fuel economy and emissions to a certain extent, while not relying on infrastructure development or being limited by driving range.

[0075] Currently, for range-extended hybrid vehicles, the preheating of the power battery is mainly achieved through a water heater (WPTC) or heat pump, or by the heat generated by the power battery itself. However, in low-temperature environments, the power battery itself has high internal resistance and low activity. Using the power battery to power the water heater (WPTC) for preheating is a single method and cannot be adapted to the vehicle's operating conditions, resulting in high overall energy consumption and a slow preheating rate for the power battery.

[0076] Based on this, this application proposes a power battery preheating control method. Under different vehicle operating conditions, the first multi-way valve and the second multi-way valve are controlled to open or close based on the current temperature of the power battery circulating water circuit or the current state of charge of the vehicle battery to preheat the power battery. This allows the preheating control to be adapted to the vehicle operating conditions and improves the accuracy of preheating control.

[0077] The preheating control of the power battery is executed based on the vehicle's thermal management system. Next, we will explain the vehicle's thermal management system.

[0078] Reference Figure 1 , Figure 1 This is a schematic diagram of the thermal management system of the range-extended electric vehicle provided in an embodiment of this application. Figure 1As shown, the thermal management system includes an engine cooling water circuit 1, a motor cooling water circuit 2, a power battery cooling water circuit 3, a first multi-way valve 4, and a second multi-way valve 5. The engine cooling water circuit 1 and the motor cooling water circuit 2 are interconnected via the first multi-way valve 4. The motor cooling water circuit 2 and the power battery cooling water circuit 3 are interconnected via the second multi-way valve 5. Thus, the first multi-way valve 4 enables heat transfer between the engine cooling water circuit 1 and the motor cooling water circuit 2. For example, if the residual heat in the motor cooling water circuit 2 is insufficient, the relatively high-temperature liquid in the engine cooling water circuit 1 can be diverted into the motor cooling water circuit 2 by adjusting the first multi-way valve 4. Simultaneously, when auxiliary cooling of the engine is required, the relatively low-temperature liquid in the motor cooling water circuit 2 can be diverted into the engine cooling water circuit 1 by adjusting the first multi-way valve 4. The second multi-way valve 5 enables heat transfer between the motor cooling water circuit 2 and the power battery cooling water circuit 3. For example, when heating the power battery is required, the relatively high-temperature liquid in the motor circulating water circuit 2 can be directed into the power battery circulating water circuit 3 by adjusting the second multi-way valve 5. Conversely, when the temperature in the motor circulating water circuit 2 is too high, the relatively low-temperature liquid in the power battery circulating water circuit 3 can be directed into the motor circulating water circuit 2 by adjusting the second multi-way valve 5. Thus, through the first and second multi-way valves, the engine circulating water circuit, motor circulating water circuit, and power battery circulating water circuit can be directly or indirectly connected, enabling heat transfer between them. This allows for comprehensive utilization of heating or cooling in the three circuits, reducing system power consumption and preventing energy waste.

[0079] Reference Figure 2 , Figure 2 This is a schematic diagram of the structure of the first multi-way valve provided in an embodiment of this application. Figure 2 As shown, the first multi-way valve 4 is provided with a first outlet 41, a second outlet 42, a first inlet 43, and a second inlet 44. A first flow path a is formed from the first inlet 43 to the first outlet 41, and a second flow path b is formed from the second inlet 44 to the second outlet 42. The flow rate of the first flow path a can be adjusted, and the flow rate of the second flow path b can be adjusted.

[0080] In this embodiment of the application, a first flow path a is formed from the first inlet 43 to the first outlet 41, and a second flow path b is formed from the second inlet 44 to the second outlet 42. That is, through the design of two flow paths, mutual communication in two directions can be achieved.

[0081] In one embodiment of this application, the opening degree of at least one of the first outlet 41 and the first inlet 43 can be adjusted to cause a corresponding change in the flow rate of the first flow path a. The opening degree of at least one of the second outlet 42 and the second inlet 44 can be adjusted to cause a corresponding change in the flow rate of the second flow path b.

[0082] In this embodiment, the flow rate of the first flow path a can be adjusted by changing the opening degree of either the first outlet 41 or the first inlet 43. Similarly, the flow rate of the second flow path b can be adjusted by changing the opening degree of either the second outlet 42 or the second inlet 44.

[0083] In one embodiment of this application, the first multi-way valve 4 is a four-way valve. The four-way valve includes a valve body and a valve core. The valve body is provided with a first outlet 41, a second outlet 42, a first inlet 43 and a second inlet 44. The valve core is disposed in the valve body to control the opening degree of the first outlet 41, the second outlet 42, the first inlet 43 and the second inlet 44.

[0084] It should be noted that the embodiments of this application do not specifically limit the first multi-way valve 4. As long as it is provided with a first outlet 41, a second outlet 42, a first inlet 43, and a second inlet 44, and a first flow path a is formed from the first inlet 43 to the first outlet 41, and a second flow path b is formed from the second inlet 44 to the second outlet 42, the first multi-way valve 4 can be a five-way valve, a six-way valve, an eight-way valve, etc., in addition to being a four-way valve.

[0085] In this embodiment, the structure of the second multi-way valve 5 is the same as that of the first multi-way valve 4. Specifically, the second multi-way valve 5 is provided with a third outlet, a fourth outlet, a third inlet, and a fourth inlet. A third flow path d is formed from the third inlet to the third outlet within the second multi-way valve, and a fourth flow path c is formed from the fourth inlet to the fourth outlet. The flow rate of the third flow path d and the flow rate of the fourth flow path c can be adjusted.

[0086] In this embodiment of the application, similarly, a third flow path d is formed from the third inlet to the third outlet, and a fourth flow path c is formed from the fourth inlet to the fourth outlet. That is, through the design of two flow paths, mutual communication in two directions can be achieved.

[0087] In one embodiment of this application, the opening degree of at least one of the third outlet and the third inlet can be adjusted to cause a corresponding change in the flow rate of the third flow path d. The opening degree of at least one of the fourth outlet and the fourth inlet can be adjusted to cause a corresponding change in the flow rate of the fourth flow path c.

[0088] Similarly, in this embodiment, the flow rate of the third flow path d can be adjusted by changing the opening degree of either the third outlet or the third inlet. The flow rate of the fourth flow path c can be adjusted by changing the opening degree of either the fourth outlet or the fourth inlet.

[0089] In one embodiment of this application, the second multi-way valve 5 is also a four-way valve. The four-way valve includes a valve body and a valve core. The valve body is provided with a third outlet, a fourth outlet, a third inlet and a fourth inlet. The valve core is disposed in the valve body to control the opening degree of the third outlet, the fourth outlet, the third inlet and the fourth inlet.

[0090] It should be noted that, similarly, the embodiments of this application do not specifically limit the second multi-way valve 5, as long as it is provided with a third outlet, a fourth outlet, a third inlet, and a fourth inlet, and a third flow path d is formed from the third inlet to the third outlet within the second multi-way valve 5, and a fourth flow path c is formed from the fourth inlet to the fourth outlet. For example, in addition to being a four-way valve, the second multi-way valve 5 can also be a five-way valve, a six-way valve, an eight-way valve, etc.

[0091] Reference Figure 1 The engine circulating water circuit 1 includes a first engine circulating water circuit and a second engine circulating water circuit. The first engine circulating water circuit includes an engine 12 and a first water pump 11. The inlet of the engine 12 is connected to the outlet of the first water pump 11 via a pipe, and the outlet of the engine 12 is connected to the inlet of the first water pump 11 via a pipe. The outlet of the engine 12 is connected to the first inlet of the first multi-way valve 4. The second circulating water circuit includes the engine 12, a thermostat 13, a first radiator 14, and the first water pump 11. The outlet of the engine 12 is connected to one end of the thermostat 13, the other end of the thermostat 13 is connected to one end of the first radiator 14, the other end of the first radiator 14 is connected to the inlet of the first water pump 11, and the outlet of the first water pump 11 is connected to the inlet of the engine 12.

[0092] Reference Figure 1The motor circulation water circuit 2 includes a generator circulation water circuit and a drive motor circulation water circuit. The generator circulation water circuit includes a generator 22, a generator controller 23, a second water pump 21, and a second radiator 24. The outlet of the second water pump 21 is connected to one end of the generator controller 23, and the other end of the generator controller 23 is connected to the inlet of the generator 22. The outlet of the generator 22 is connected to one end of the second radiator 24, and the other end of the second radiator 24 is connected to the inlet of the second water pump 21. The outlet of the generator 22 is also connected to the second inlet of the first multi-way valve 4. The drive motor circulation water circuit includes a drive motor 25, a drive motor controller 26, a second water pump 21, and a second radiator 24. The outlet of the second water pump 21 is also connected to one end of the drive motor controller 26, and the other end of the drive motor controller 26 is connected to the inlet of the drive motor 25. The outlet of the drive motor 25 is connected to one end of the second radiator 24, and the other end of the second radiator 24 is connected to the inlet of the second water pump 21. The outlet of the drive motor 25 is also connected to the third inlet of the second multi-way valve 5. The motor circulation water circuit and the drive motor circulation water circuit share the second radiator 24 and the second water pump 21. The heat generated by the generator, generator controller, drive motor, and drive motor controller can all be released through the second radiator.

[0093] Reference Figure 1The power battery circulating water circuit 3 includes a power battery heating circulating water circuit, a power battery cooling circulating water circuit, and a cooling circuit. The power battery heating circulating water circuit includes a third water pump 31, a power battery 32, and a water heater 33. The outlet of the third water pump 31 is connected to one end of the water heater 33, the other end of the water heater 33 is connected to the inlet of the power battery 32, and the outlet of the power battery 32 is connected to the inlet of the third water pump 31. The inlet of the power battery 32 is connected to the third outlet of the second multi-way valve 5. The power battery cooling circulating water circuit includes a third water pump 31, a power battery 32, and a refrigerant heat exchanger 34. The outlet of the third water pump 31 is connected to one end of the refrigerant heat exchanger 34, the other end of the refrigerant heat exchanger 34 is connected to the inlet of the power battery 32, and the outlet of the power battery 32 is connected to the inlet of the third water pump 31. The cooling circuit includes a liquid receiver 35, a condenser 36, a compressor 37, and a refrigerant heat exchanger 34. The liquid receiver 35, condenser 36, compressor 37, and refrigerant heat exchanger 34 are connected sequentially via pipelines. The power battery heating circulating water circuit and the power battery cooling circulating water circuit share the power battery 32 and the third water pump 31. When the ambient temperature of the power battery is low and preheating is required, the power battery heating circulating water circuit is operated, i.e., the coolant in the circulating water circuit is heated by the water heater 33, to ensure the power battery operates at a suitable temperature. The cooling circuit and the power battery cooling circulating water circuit share the refrigerant heat exchanger 33. When the ambient temperature of the power battery is high and cooling is required, the power battery cooling circulating water circuit and the cooling circuit are operated, i.e., the coolant in the circulating water circuit is lowered by the refrigerant heat exchanger 334, to cool the power battery.

[0094] Reference Figure 3 , Figure 3 This is a flowchart of a power battery preheating control method provided in an embodiment of this application. The method includes... Figure 1 The thermal management system of the vehicle shown is executed, including but not limited to steps S310 to S340.

[0095] Step S310: Detect whether the current temperature of the power battery circulating water circuit is less than or equal to the lower limit threshold of the operating temperature.

[0096] In this embodiment, the optimal operating temperature of the lithium battery is around 25°C, and the suitable operating temperature range is approximately 0–40°C. If the battery is discharged at low temperatures, the discharge reaction is slow, its performance cannot be fully realized, and the battery's reliability is affected. Furthermore, charging the battery at low temperatures can easily lead to lithium plating, causing irreversible damage.

[0097] In this embodiment, after the vehicle is powered on, the system checks whether the engine coolant temperature sensor, the power battery circulating water circuit temperature sensor, the engine speed sensor, and the power battery state of charge (SOC) monitoring function are normal. If they are not normal, the system enters a fault mode and issues a fault alarm. If they are normal, the system determines whether the current temperature TOL of the power battery circulating water circuit meets the battery operating temperature threshold range (TOLmin~TOLmax), where TOLmin represents the lower threshold of the power battery operating temperature, and TOLmax represents the upper threshold of the power battery operating temperature. If the current temperature TOL of the power battery circulating water circuit is within the battery operating temperature threshold range, i.e., if TOLmin < TOL < TOLmax, the power battery temperature is suitable, and the battery does not require cooling or preheating. If TOL ≥ TOLmax, the power battery operating temperature is too high, and the power battery circulating water circuit needs cooling. If TOL ≤ TOLmin, the power battery operating temperature is too low, and the power battery circulating water circuit needs preheating.

[0098] In this embodiment of the application, by detecting whether the current temperature of the power battery circulation water circuit is less than or equal to the lower limit threshold TOLmin of the operating temperature, it can be determined whether the power battery needs to be preheated. Thus, when the current temperature of the power battery circulation water circuit is detected to be less than or equal to the lower limit threshold TOLmin of the operating temperature, the power battery can be preheated.

[0099] Step S320: When the current temperature of the power battery circulating water circuit is less than or equal to the lower limit threshold, obtain the current operating status of the vehicle.

[0100] In this embodiment, when the current temperature of the power battery's circulating water circuit is detected to be less than or equal to the lower threshold, it indicates that the power battery temperature is too low. At this point, the battery cell temperature is low, and its activity is reduced. Consequently, its charging and discharging characteristics are poor, resulting in low charging efficiency, long charging times, and even failure to charge at extremely low temperatures. Similarly, the discharging process cannot release significant power or achieve the intended acceleration or overtaking maneuvers. Therefore, to avoid charging and discharging the power battery under low-temperature conditions, it is necessary to preheat the power battery until its temperature rises to within the battery operating temperature threshold range before proceeding with charging and discharging operations.

[0101] In this embodiment, when the current temperature of the power battery's circulating water circuit is detected to be less than or equal to the lower threshold, it indicates that the power battery temperature is too low and preheating is required. At this time, the vehicle's current operating status is first obtained to determine its operating conditions. Subsequently, preheating control can be adapted to these conditions, improving the accuracy of preheating control.

[0102] Step S330: When the vehicle is determined to be in the first operating condition based on the current operating status of the vehicle, the first multi-way valve and the second multi-way valve are controlled to open or close according to the current temperature of the power battery circulating water circuit in order to preheat the power battery. The first operating condition includes the engine speed being 0 or the range extender operating time being less than or equal to a preset time threshold.

[0103] In this embodiment, when the vehicle is determined to be in a first operating condition based on its current operating status, such as when the engine speed is detected to be 0, meaning the engine is not currently running, the first and second multi-way valves are controlled to open or close based on the current temperature of the power battery circulating water circuit to preheat the power battery. For example, after the vehicle has been parked for a period of time, the ambient temperature may be low, causing the power battery temperature to drop below the lower limit threshold TOLmin of the operating temperature. If the vehicle needs to be started and driven at this time, the first and second multi-way valves need to be controlled to open or close based on the current temperature of the power battery circulating water circuit to preheat the power battery and prevent it from discharging under low-temperature conditions.

[0104] In this embodiment, when the vehicle is determined to be in a first operating condition based on its current operating status, such as when the range extender's operating time is less than or equal to a preset time threshold, the first and second multi-way valves need to be opened or closed according to the current temperature of the power battery circulating water circuit to preheat the power battery. For example, if the engine is running but the range extender's operating time is less than or equal to the preset time threshold, i.e., the vehicle has just started, the first and second multi-way valves also need to be opened or closed according to the current temperature of the power battery circulating water circuit to preheat the power battery and prevent it from discharging under low-temperature conditions.

[0105] Reference Figure 4 , Figure 4 This application provides a flowchart of steps for controlling the opening or closing of the first and second multi-way valves based on the current temperature of the power battery's circulating water circuit to preheat the power battery, including but not limited to steps S410 to S430.

[0106] Step S410: When the current temperature of the power battery circulating water circuit is less than or equal to the lower limit threshold but greater than the first temperature threshold, the power battery is preheated according to the first preheating mode. The first preheating mode includes controlling both the first multi-way valve and the second multi-way valve to be disconnected, and controlling the range extender to supply power to the water heater so that the water heater can heat.

[0107] In this embodiment, when the vehicle is in the first operating condition, different preheating controls are implemented based on the current temperature of the power battery circulating water circuit. Specifically, when the current temperature of the power battery circulating water circuit is less than or equal to the lower threshold but greater than the first temperature threshold (i.e., TOL1 < TOL ≤ TOLmin), the power battery is preheated according to the first preheating mode. This involves controlling both the first and second multi-way valves to be disconnected, and controlling the range extender to supply power to the water heater so that the water heater can heat the battery.

[0108] Reference Figure 5 , Figure 5 This is a flowchart of the steps performed after preheating the power battery according to the first preheating mode, as provided in the embodiments of this application, including but not limited to steps S510 to S540.

[0109] Step S510: Detect the rate of temperature change in the power battery circulating water circuit;

[0110] Step S520: When the rate of temperature change is less than the lower limit of the preset rate of temperature change, switch to the second preheating mode to preheat the power battery.

[0111] Step S530: When the rate of temperature change exceeds the upper limit of the preset rate of temperature change, enter the fault mode and issue a fault alarm.

[0112] Step S540: When the temperature change rate is between the lower limit and the upper limit of the preset temperature change rate, the power battery is preheated according to the first preheating mode until the current temperature of the power battery circulation water circuit exceeds the lower limit threshold.

[0113] In this embodiment, considering that preheating the power battery according to the first preheating mode cannot meet the preheating response requirements, after preheating the power battery according to the first preheating mode, it is necessary to further detect the temperature change rate ΔTOLn+1 of the power battery circulating water circuit to determine whether the current preheating according to the first preheating mode is appropriate. Specifically, if the temperature change rate ΔTOLn+1 is less than the preset lower limit value ΔTOLmin, i.e., ΔTOLn+1 < ΔTOLmin, it indicates that the temperature rise is slow and cannot meet the preheating response requirements when preheating according to the first preheating mode. Therefore, in order to further improve the preheating rate, it is necessary to switch to the second preheating mode to preheat the power battery. If the temperature change rate ΔTOLn+1 is greater than the preset upper limit value ΔTOLmax, i.e., ΔTOLn+1 > ΔTOLmax, it indicates that the temperature rises rapidly, which may be due to water leakage, blockage of the power battery circulating water circuit, or failure of the water heater. Therefore, a fault mode is entered and a fault alarm is issued. If the rate of temperature change ΔTOLn+1 is between the lower limit ΔTOLmin and the upper limit ΔTOLmax of the preset rate of temperature change, i.e. ΔTOLmin≤ΔTOLn+1≤ΔTOLmax, it indicates that the current heat supply is reasonable and the temperature rise meets the standard. Therefore, the power battery can be preheated according to the first preheating mode until the current temperature TOL of the power battery circulation water circuit exceeds the lower limit threshold TOLmin.

[0114] In one embodiment of this application, detecting the rate of temperature change in the power battery circulating water circuit includes:

[0115] The current temperature of the power battery's circulating water circuit is obtained at preset intervals;

[0116] The rate of temperature change of the power battery circulating water circuit is calculated based on the current temperature of at least two power battery circulating water circuits.

[0117] In this embodiment of the application, after the power battery is preheated according to the first preheating mode, the current temperature of the power battery circulating water circuit can be obtained at preset time intervals T. For example, the current temperature TOL of the power battery circulating water circuit at time t1 can be obtained. t1 Obtain the current temperature TOL of the power battery circulating water circuit at time t2. t2 Obtain the current temperature TOL of the power battery circulating water circuit at time t3. t3 Where the time interval between time t1 and time t2 is T, and the time interval between time t3 and time t2 is T. Therefore, the current temperature TOL of the power battery circulating water circuit at time t2 is... t2 Subtract the current temperature TOL of the power battery circulating water circuit at time t1.t1 The temperature difference, divided by the time interval T, can be used to calculate the temperature change rate ΔTOLn+1 of the power battery's circulating water circuit.

[0118] Reference Figure 6 , Figure 6 This is a flowchart of the steps performed after switching to the second preheating mode to preheat the power battery when the temperature change rate is less than the lower limit of the preset temperature change rate, provided in the embodiments of this application, including but not limited to steps S610 to S630.

[0119] Step S610: Detect the temperature change rate of the power battery circulating water circuit again;

[0120] Step S620: When the rate of temperature change is less than the lower limit of the preset rate of temperature change, switch to the third preheating mode to preheat the power battery until the current temperature of the power battery circulation water circuit exceeds the lower limit threshold.

[0121] Step S630: When the temperature change rate is between the lower limit and the upper limit of the preset temperature change rate, the power battery is preheated according to the second preheating mode until the current temperature of the power battery circulation water circuit exceeds the lower limit threshold.

[0122] In this embodiment, when the vehicle is in the first operating condition, if the current temperature TOL of the power battery circulating water circuit is less than or equal to the lower limit threshold TOLmin but greater than the first temperature threshold TOL1, it indicates that the power battery temperature is too low. In this case, the power battery needs to be preheated according to the first preheating mode. Considering that the preheating response requirements cannot be met even after preheating the power battery according to the first preheating mode, the appropriateness of the current preheating mode can be determined by detecting the temperature change rate ΔTOLn+1 of the power battery circulating water circuit. When the temperature change rate ΔTOLn+1 of the power battery circulating water circuit is less than the preset lower limit value ΔTOLmin, that is, ΔTOLn+1 < ΔTOLmin, it indicates that the temperature rise is slow and cannot meet the preheating response requirements when preheating according to the first preheating mode. Therefore, in order to further improve the preheating rate, it is necessary to switch to the second preheating mode to preheat the power battery. Even after switching to the second preheating mode to preheat the power battery, there may still be situations where the preheating response requirements cannot be met. Therefore, the suitability of the current preheating mode can be determined by re-detecting the temperature change rate ΔTOLn+1 of the power battery's circulating water circuit. If the temperature change rate ΔTOLn+1 of the power battery's circulating water circuit is less than the preset lower limit ΔTOLmin (i.e., ΔTOLn+1 < ΔTOLmin), it indicates that switching to the second preheating mode still results in a slow temperature rise and fails to meet the preheating response requirements. Therefore, to further improve the preheating rate, it is necessary to switch to the third preheating mode to preheat the power battery until the current temperature of the power battery's circulating water circuit exceeds the lower threshold. If the temperature change rate ΔTOLn+1 is between the preset lower limit ΔTOLmin and upper limit ΔTOLmax, then the second preheating mode should be maintained until the current temperature TOL of the power battery's circulating water circuit exceeds the lower threshold TOLmin.

[0123] Step S420: When the current temperature of the power battery circulating water circuit is less than or equal to the first temperature threshold but greater than the second temperature threshold, the power battery is preheated according to the second preheating mode. The second preheating mode includes controlling the first multi-way valve to open, the second multi-way valve to open, and controlling the range extender to supply power to the water heater so that the water heater can heat.

[0124] In this embodiment, when the vehicle is in the first operating condition, different preheating controls are implemented based on the current temperature of the power battery circulating water circuit. Specifically, when the current temperature TOL of the power battery circulating water circuit is less than or equal to the first temperature threshold TOL1 but greater than the second temperature threshold TOL2, it indicates that the power battery temperature is low. In this case, considering that only controlling the range extender to supply power to the water heater for heating (i.e., only preheating the power battery according to the first preheating mode) results in a slow preheating rate and untimely preheating response, this embodiment, while controlling the range extender to supply power to the water heater for heating, further controls the first multi-way valve to open and the second multi-way valve to open. This allows the medium-temperature water in the motor circulating water circuit to flow into the power battery circulating water circuit to further heat the power battery, thereby improving the preheating rate. That is, the power battery is preheated according to the second preheating mode.

[0125] Reference Figure 7 , Figure 7 This is a flowchart of the steps to be performed when the current temperature of the power battery circulating water circuit is less than or equal to a first temperature threshold but greater than a second temperature threshold, provided in the embodiments of this application, including but not limited to steps S710 to S730.

[0126] Step S710: Detect whether the temperature of the motor circulating water circuit is greater than or equal to the lower limit threshold of the temperature of the motor circulating water circuit flowing to the power battery circulating water circuit.

[0127] Step S720: When the temperature of the motor circulating water circuit is lower than the lower limit threshold of the temperature of the motor circulating water circuit flowing to the power battery circulating water circuit, the power battery is preheated according to the first preheating mode.

[0128] Step S730: When the temperature of the motor circulating water circuit is greater than or equal to the lower limit threshold of the temperature of the motor circulating water circuit flowing to the power battery circulating water circuit, the power battery is preheated according to the second preheating mode until the current temperature of the power battery circulating water circuit exceeds the lower limit threshold.

[0129] In this embodiment, when the vehicle is in the first operating condition, if the current temperature TOL of the power battery circulating water circuit is less than or equal to the first temperature threshold TOL1 but greater than the second temperature threshold TOL2, it indicates that the power battery temperature is low. In this case, the power battery needs to be preheated according to the second preheating mode to quickly meet the preheating response requirements. However, it is necessary to determine whether the temperature TOM of the motor circulating water circuit is greater than or equal to the lower limit threshold TOMmin of the temperature flowing from the motor circulating water circuit to the power battery circulating water circuit. If the temperature TOM of the motor circulating water circuit is greater than or equal to the lower limit threshold TOMmin of the temperature flowing from the motor circulating water circuit to the power battery circulating water circuit (i.e., TOM ≥ TOMmin), then while controlling the range extender to supply power to the water heater to heat the water heater, the first multi-way valve is also controlled to open and the second multi-way valve is controlled to open, allowing the medium-temperature water in the motor circulating water circuit to flow to the power battery circulating water circuit, further assisting in the preheating of the power battery and improving the preheating rate. If the temperature TOM of the motor circulating water circuit is less than the lower limit threshold TOMmin of the temperature range from the motor circulating water circuit to the power battery circulating water circuit (i.e., TOM < TOMmin), then even if the first multi-way valve is opened and the second multi-way valve is opened, meaning even if water from the motor circulating water circuit flows into the power battery circulating water circuit, the temperature of the power battery circulating water circuit cannot be increased because TOM < TOMmin. Therefore, the power battery is preheated only according to the first preheating mode until the temperature TOM of the motor circulating water circuit is detected to be greater than or equal to the lower limit threshold TOMmin of the temperature range from the motor circulating water circuit to the power battery circulating water circuit, then the second preheating mode is switched to preheat the power battery.

[0130] Step S430: When the current temperature of the power battery circulating water circuit is less than or equal to the second temperature threshold, the power battery is preheated according to the third preheating mode. The third preheating mode includes controlling both the first multi-way valve and the second multi-way valve to be turned on, and controlling the range extender to supply power to the water heater so that the water heater can heat.

[0131] In this embodiment, when the vehicle is in the first operating condition, different preheating controls are implemented based on the current temperature of the power battery circulating water circuit. Specifically, when the current temperature TOL of the power battery circulating water circuit is less than or equal to the second temperature threshold TOL2, it indicates that the power battery temperature is extremely low. In this case, to increase the preheating rate, while controlling the range extender to supply power to the water heater to heat it, both the first and second multi-way valves are simultaneously opened. This allows the high-temperature water in the engine circulating water circuit and the medium-temperature water in the motor circulating water circuit to flow into the power battery circulating water circuit, further heating the power battery. That is, preheating the power battery according to the third preheating mode can increase the preheating rate while reducing energy consumption.

[0132] Reference Figure 8 , Figure 8 This is a flowchart of the steps to be performed when the current temperature of the power battery circulating water circuit is less than or equal to a second temperature threshold, provided in the embodiments of this application, including but not limited to steps S810 to S850.

[0133] Step S810: Detect whether the temperature of the engine circulating water circuit is greater than or equal to the lower limit threshold of the temperature of the engine circulating water circuit flowing to the motor circulating water circuit, and detect whether the temperature of the motor circulating water circuit is greater than or equal to the lower limit threshold of the temperature of the motor circulating water circuit flowing to the power battery circulating water circuit.

[0134] Step S820: When the temperature of the engine circulating water circuit is lower than the lower limit threshold of the temperature of the engine circulating water circuit flowing to the motor circulating water circuit, and the temperature of the motor circulating water circuit is lower than the lower limit threshold of the temperature of the motor circulating water circuit flowing to the power battery circulating water circuit, the power battery is preheated according to the first preheating mode.

[0135] Step S830: When the temperature of the engine circulating water circuit is lower than the lower limit threshold of the temperature of the engine circulating water circuit flowing to the motor circulating water circuit, but the temperature of the motor circulating water circuit is greater than or equal to the lower limit threshold of the temperature of the motor circulating water circuit flowing to the power battery circulating water circuit, the power battery is preheated according to the second preheating mode.

[0136] Step S840: When the temperature of the engine circulating water circuit is greater than or equal to the lower limit threshold of the temperature of the engine circulating water circuit flowing to the motor circulating water circuit, but the temperature of the motor circulating water circuit is less than the lower limit threshold of the temperature of the motor circulating water circuit flowing to the power battery circulating water circuit, control the first multi-way valve to open and the second multi-way valve to close until the temperature of the motor circulating water circuit is greater than or equal to the lower limit threshold of the temperature of the motor circulating water circuit flowing to the power battery circulating water circuit.

[0137] Step S850: When the temperature of the motor circulating water circuit is greater than or equal to the lower limit threshold of the temperature of the motor circulating water circuit flowing to the power battery circulating water circuit, and the temperature of the engine circulating water circuit is greater than or equal to the lower limit threshold of the temperature of the engine circulating water circuit flowing to the motor circulating water circuit, the power battery is preheated according to the third preheating mode until the current temperature of the power battery circulating water circuit exceeds the lower limit threshold.

[0138] In this embodiment of the application, when the vehicle is in the first operating condition, if the current temperature TOL of the power battery circulating water circuit is less than or equal to the second temperature threshold TOL2, i.e., TOL≤TOL2, it indicates that the temperature of the power battery is extremely low. At this time, it is necessary to first detect whether the temperature TOH of the engine circulating water circuit is greater than or equal to the lower limit threshold TOHmin of the temperature flowing from the engine circulating water circuit to the motor circulating water circuit, and detect whether the temperature TOM of the motor circulating water circuit is greater than or equal to the lower limit threshold TOMmin of the temperature flowing from the motor circulating water circuit to the power battery circulating water circuit. If the temperature TOH of the engine circulating water circuit is greater than or equal to the lower limit threshold TOHmin of the temperature flowing from the engine circulating water circuit to the motor circulating water circuit, and the temperature TOM of the motor circulating water circuit is greater than or equal to the lower limit threshold TOMmin of the temperature flowing from the motor circulating water circuit to the power battery circulating water circuit, i.e., TOH≥TOHmin and TOM≥TOMmin, then the power battery can be preheated according to the third preheating mode until the current temperature of the power battery circulating water circuit exceeds the lower limit threshold. If the temperature TOH of the engine circulating water circuit is less than the lower limit threshold TOHmin of the temperature range from the engine circulating water circuit to the motor circulating water circuit, and the temperature TOM of the motor circulating water circuit is less than the lower limit threshold TOMmin of the temperature range from the motor circulating water circuit to the power battery circulating water circuit (i.e., TOH < TOHmin, and TOM < TOMmin), then the power battery can only be preheated according to the first preheating mode. If the temperature TOH of the engine circulating water circuit is less than the lower limit threshold TOHmin of the temperature range from the engine circulating water circuit to the motor circulating water circuit, but the temperature TOM of the motor circulating water circuit is greater than or equal to the lower limit threshold TOMmin of the temperature range from the motor circulating water circuit to the power battery circulating water circuit (i.e., TOH < TOHmin, but TOM ≥ TOMmin), then the power battery can be preheated according to the second preheating mode. If the temperature TOH of the engine circulating water circuit is greater than or equal to the lower limit threshold TOHmin of the temperature flowing from the engine circulating water circuit to the motor circulating water circuit, but the temperature TOM of the motor circulating water circuit is less than the lower limit threshold TOMmin of the temperature flowing from the motor circulating water circuit to the power battery circulating water circuit (i.e., TO≥TOHmin, but TOM<TOMmin), then the first multi-way valve is opened and the second multi-way valve is closed, allowing the high-temperature water in the engine circulating water circuit to flow into the motor circulating water circuit. This allows the temperature TOM of the motor circulating water circuit to gradually rise to exceed the lower limit threshold TOMmin of the temperature flowing from the motor circulating water circuit to the power battery circulating water circuit. Then, the power battery can be preheated according to the third preheating mode until the current temperature TOL of the power battery circulating water circuit exceeds the lower limit threshold TOLmin.

[0139] Step S340: When it is determined that the vehicle is in the second operating condition based on the current operating status of the vehicle, the first multi-way valve and the second multi-way valve are controlled to open or close according to the current state of charge of the power battery in order to preheat the power battery. The second operating condition includes the range extender running time being greater than a preset time threshold.

[0140] In this embodiment of the application, when it is determined that the vehicle is in the second operating condition based on the current operating status of the vehicle, for example, when it is detected that the operating time of the range extender is greater than a preset time threshold, that is, the range extender has been in the working state in the early stage, and the battery needs to be preheated during the vehicle driving process, the first multi-way valve and the second multi-way valve can be turned on or off according to the current state of charge of the power battery to preheat the power battery and prevent the power battery from charging under low temperature conditions.

[0141] Reference Figure 9 , Figure 9 This application provides a flowchart of steps for controlling the first and second multi-way valves to open or close based on the current state of charge of the power battery in order to preheat the power battery, including but not limited to steps S910 to S940.

[0142] Step S910: When the current state of charge of the power battery is greater than the limit of the state of charge threshold of the extreme depletion but less than or equal to the state of charge threshold of the allowable pure electric operation, the power battery is preheated according to the second preheating mode. The second preheating mode includes controlling the first multi-way valve to open, the second multi-way valve to open, and controlling the range extender to supply power to the water heater so that the water heater can heat.

[0143] Step S920: When the current state of charge of the power battery is greater than the charge state threshold that allows pure electric operation, detect whether the vehicle is in fuel priority mode or electric priority mode.

[0144] Step S930: When the vehicle is in fuel priority mode, the power battery is preheated according to the second preheating mode.

[0145] Step S940: When the vehicle is in the power priority mode, the power battery is preheated according to the third preheating mode. The third preheating mode includes controlling the first multi-way valve and the second multi-way valve to be turned on, and controlling the range extender to supply power to the water heater so that the water heater can heat.

[0146] In this embodiment, when the vehicle is in the second operating condition, different preheating controls are implemented based on the different current states of charge (SOC) of the power battery. Specifically, when the current SOC of the power battery is greater than the SOC threshold for extreme depletion... min But less than or equal to the state of charge (SOC) threshold that allows for pure electric operation. limit That is, SOC min <SOC≤SOClimit This indicates that the current state of charge (SOC) of the power battery is low. To prevent the battery from charging under low-temperature conditions, it needs to be preheated. Specifically, to quickly increase the battery temperature, the power battery is preheated according to the second preheating mode. This involves controlling the range extender to supply power to the water heater, simultaneously opening the first multi-way valve and opening the second multi-way valve. This allows medium-temperature water from the motor's circulating water circuit to flow into the power battery's circulating water circuit, assisting in preheating the battery and increasing the preheating rate. When the current SOC of the power battery is greater than the allowable pure electric operation threshold SOC... limit That is, SOC > SOC limit This indicates that the current state of charge of the power battery is sufficient for pure electric range. At this point, it's possible to further determine whether the vehicle is in fuel-priority mode or electric-priority mode to decide which preheating mode to use for the power battery. Specifically, considering that the preheating response requirement is relatively low in fuel-priority mode, the second preheating mode can be used to preheat the power battery. Conversely, if the vehicle is in electric-priority mode, the preheating response requirement is higher, thus requiring the third preheating mode to meet the preheating response requirements.

[0147] Reference Figure 10 , Figure 10 This is a flowchart of the steps performed after preheating the power battery according to the second preheating mode, as provided in the embodiments of this application, including but not limited to steps S1010 to S1040.

[0148] Step S1010: Detect the rate of temperature change in the power battery's circulating water circuit;

[0149] Step S1020: When the rate of temperature change is less than the lower limit of the preset rate of temperature change, switch to the third preheating mode to preheat the power battery until the current temperature of the power battery circulation water circuit exceeds the lower limit threshold.

[0150] Step S1030: When the rate of temperature change exceeds the upper limit of the preset rate of temperature change, enter the fault mode and issue a fault alarm.

[0151] Step S1040: When the temperature change rate is between the lower limit and the upper limit of the preset temperature change rate, the power battery is preheated according to the second preheating mode until the current temperature of the power battery circulation water circuit exceeds the lower limit threshold.

[0152] In this embodiment of the application, when the vehicle is in the second operating condition, if the current state of charge (SOC) of the power battery is greater than the SOC threshold for extreme depletion, min But less than or equal to the state of charge (SOC) threshold that allows for pure electric operation.limit That is, SOC min <SOC≤SOC limit This indicates that the current state of charge (SOC) of the power battery is low, and preheating is required according to the second preheating mode. When the current SOC of the power battery is greater than the SOC threshold for pure electric operation... limit That is, SOC > SOC limit This indicates that the current state of charge of the power battery is sufficient for pure electric range. If the vehicle is in fuel-priority mode, the power battery needs to be preheated according to the second preheating mode. After preheating the power battery according to the second preheating mode, the suitability of the current preheating mode can be determined by detecting the temperature change rate of the power battery's circulating water circuit. Specifically, when the temperature change rate ΔTOLn+1 of the power battery's circulating water circuit is less than the preset lower limit value ΔTOLmin, i.e., ΔTOLn+1 < ΔTOLmin, it means that preheating according to the second preheating mode results in a slow temperature rise and cannot meet the preheating response requirements. Therefore, to further improve the preheating rate, it is necessary to switch to the third preheating mode to preheat the power battery until the current temperature of the power battery's circulating water circuit exceeds the lower threshold. If the temperature change rate ΔTOLn+1 is between the preset lower limit ΔTOLmin and upper limit ΔTOLmax, it indicates that the current heat supply is reasonable and the temperature rise meets the standard. Therefore, the power battery can be preheated according to the second preheating mode until the current temperature TOL of the power battery circulation water circuit exceeds the lower limit threshold TOLmin.

[0153] In this embodiment, under low-temperature conditions, the engine circulating water circuit, motor circulating water circuit, and power battery circulating water circuit can be switched on or off by controlling the first and second multi-way valves according to different operating conditions of the vehicle. This allows for the efficient use of high-temperature heat source water to directly preheat the lower-temperature power battery circulating water circuit, resulting in a more even temperature rise in the power battery and improved overall battery performance. Simultaneously, by controlling the on / off state of the first and second multi-way valves, waste heat can be utilized to increase the temperature of the power battery circulating water circuit, reducing the power demand of the water heater and lowering overall vehicle cost and energy consumption. Combining the medium-temperature water in the motor circulating water circuit and the high-temperature water and water heater in the engine circulating water circuit for preheating the power battery further improves the preheating rate, enabling the power battery to quickly operate at a suitable temperature, i.e., rapid preheating response.

[0154] This application also provides a vehicle, which includes embodiments of this application. Figure 1 The thermal management system shown is used by the vehicle to execute the power battery preheating control method provided in any embodiment of this application.

[0155] Since the vehicle provided in this application implements the power battery preheating control method provided in any embodiment of this application, the preheating control can be adapted to the vehicle's operating conditions, thereby improving the accuracy of the preheating control.

[0156] The embodiments described in this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided by the embodiments of this application. As those skilled in the art will know, with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems.

[0157] Those skilled in the art will understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of this application, and may include more or fewer steps than shown, or combine certain steps, or different steps.

[0158] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0159] Those skilled in the art will understand that all or some of the steps in the methods disclosed above, as well as the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, or suitable combinations thereof.

[0160] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0161] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0162] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of the units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0163] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0164] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0165] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes multiple instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing programs, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0166] The preferred embodiments of the present application have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present application. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and substance of the embodiments of the present application shall be within the scope of the claims of the present application.

Claims

1. A power battery preheating control method applied to a thermal management system of a vehicle, characterized in that, The thermal management system includes an engine circulating water circuit, a motor circulating water circuit, a power battery circulating water circuit, a first multi-way valve, and a second multi-way valve. The engine circulating water circuit is connected to the motor circulating water circuit through the first multi-way valve to form a circulation loop. The motor circulating water circuit is connected to the power battery circulating water circuit through the second multi-way valve to form a circulation loop. The power battery circulating water circuit includes a water heater for heating the power battery circulating water circuit. The control method includes: Detect whether the current temperature of the power battery circulation water circuit is less than or equal to the lower limit threshold of the operating temperature; When the current temperature of the power battery circulating water circuit is less than or equal to the lower limit threshold, the current operating status of the vehicle is obtained; When the vehicle is determined to be in the first operating condition based on the current operating status of the vehicle, the first multi-way valve and the second multi-way valve are controlled to open or close according to the current temperature of the power battery circulating water circuit in order to preheat the power battery. The first operating condition includes an engine speed of 0 or the range extender operating time being less than or equal to a preset time threshold. When the vehicle is determined to be in a second operating condition based on its current operating status, the first multi-way valve and the second multi-way valve are controlled to open or close according to the current state of charge of the power battery in order to preheat the power battery. The second operating condition includes the range extender operating time being greater than the preset time threshold.

2. The method of claim 1, wherein, Controlling the first and second multi-way valves to open or close based on the current temperature of the power battery circulating water circuit to preheat the power battery includes: When the current temperature of the power battery circulating water circuit is less than or equal to the lower limit threshold but greater than the first temperature threshold, the power battery is preheated according to the first preheating mode. The first preheating mode includes controlling the first multi-way valve and the second multi-way valve to be disconnected, and controlling the range extender to supply power to the water heater so that the water heater can heat. When the current temperature of the power battery circulating water circuit is less than or equal to the first temperature threshold but greater than the second temperature threshold, the power battery is preheated according to the second preheating mode. The second preheating mode includes controlling the first multi-way valve to open, the second multi-way valve to open, and controlling the range extender to supply power to the water heater so that the water heater can heat. When the current temperature of the power battery circulating water circuit is less than or equal to the second temperature threshold, the power battery is preheated according to the third preheating mode. The third preheating mode includes controlling both the first multi-way valve and the second multi-way valve to be open, and controlling the range extender to supply power to the water heater so that the water heater can heat.

3. The method of claim 2, wherein, After preheating the power battery according to the first preheating mode, the method further includes: Detect the rate of temperature change in the power battery's circulating water circuit; When the rate of temperature change is less than the lower limit of the preset rate of temperature change, the power battery is preheated according to the second preheating mode. When the rate of temperature change exceeds the upper limit of the preset rate of temperature change, the system enters a fault mode and issues a fault alarm. When the rate of temperature change is between the lower limit and the upper limit of the preset rate of temperature change, the power battery is preheated according to the first preheating mode until the current temperature of the power battery circulation water circuit exceeds the lower limit threshold.

4. The method of claim 3, wherein, The detection of the temperature change rate of the power battery circulating water circuit includes: The current temperature of the power battery circulation water circuit is obtained at preset time intervals; The rate of temperature change of the power battery circulation water circuit is calculated based on the current temperature of at least two of the power battery circulation water circuits.

5. The method of claim 3, wherein, When the rate of temperature change is less than a preset lower limit for the rate of temperature change, after switching to the second preheating mode to preheat the power battery, the method further includes: The rate of temperature change in the power battery's circulating water circuit was detected again. When the rate of temperature change is less than the lower limit of the preset rate of temperature change, the power battery is preheated according to the third preheating mode until the current temperature of the power battery circulation water circuit exceeds the lower limit threshold. When the rate of temperature change is between the lower limit and the upper limit of the preset rate of temperature change, the power battery is preheated according to the second preheating mode until the current temperature of the power battery circulation water circuit exceeds the lower limit threshold.

6. The method of claim 2, wherein, When the current temperature of the power battery circulating water circuit is less than or equal to the first temperature threshold but greater than the second temperature threshold, the method further includes: Detect whether the temperature of the motor circulating water circuit is greater than or equal to the lower temperature threshold of the water flowing from the motor circulating water circuit to the power battery circulating water circuit; When the temperature of the motor circulating water circuit is lower than the lower limit threshold of the temperature of the motor circulating water circuit flowing to the power battery circulating water circuit, the power battery is preheated according to the first preheating mode; When the temperature of the motor circulating water circuit is greater than or equal to the lower limit threshold of the temperature at which the motor circulating water circuit flows to the power battery circulating water circuit, the power battery is preheated according to the second preheating mode until the current temperature of the power battery circulating water circuit exceeds the lower limit threshold.

7. The method of claim 2, wherein, When the current temperature of the power battery circulating water circuit is less than or equal to the second temperature threshold, the method further includes: The temperature of the engine circulating water circuit is detected to be greater than or equal to the lower limit threshold of the temperature of the engine circulating water circuit flowing to the motor circulating water circuit, and the temperature of the motor circulating water circuit is detected to be greater than or equal to the lower limit threshold of the temperature of the motor circulating water circuit flowing to the power battery circulating water circuit. When the temperature of the engine circulating water circuit is lower than the lower limit threshold of the temperature of the engine circulating water circuit flowing to the motor circulating water circuit, and the temperature of the motor circulating water circuit is lower than the lower limit threshold of the temperature of the motor circulating water circuit flowing to the power battery circulating water circuit, the power battery is preheated according to the first preheating mode. When the temperature of the engine circulating water circuit is lower than the lower limit threshold of the temperature of the engine circulating water circuit flowing to the motor circulating water circuit, but the temperature of the motor circulating water circuit is greater than or equal to the lower limit threshold of the temperature of the temperature of the motor circulating water circuit flowing to the power battery circulating water circuit, the power battery is preheated according to the second preheating mode; When the temperature of the engine circulating water circuit is greater than or equal to the lower limit threshold of the temperature of the engine circulating water circuit flowing to the motor circulating water circuit, but the temperature of the motor circulating water circuit is less than the lower limit threshold of the temperature of the motor circulating water circuit flowing to the power battery circulating water circuit, the first multi-way valve is controlled to open and the second multi-way valve is controlled to close until the temperature of the motor circulating water circuit is greater than or equal to the lower limit threshold of the temperature of the motor circulating water circuit flowing to the power battery circulating water circuit. When the temperature of the motor circulating water circuit is greater than or equal to the lower limit threshold of the temperature of the motor circulating water circuit flowing to the power battery circulating water circuit, and the temperature of the engine circulating water circuit is greater than or equal to the lower limit threshold of the temperature of the engine circulating water circuit flowing to the motor circulating water circuit, the power battery is preheated according to the third preheating mode until the current temperature of the power battery circulating water circuit exceeds the lower limit threshold.

8. The method of claim 1, wherein, Controlling the first and second multi-way valves to open or close according to the current state of charge of the power battery to preheat the power battery includes: When the current state of charge of the power battery is greater than the limit of the state of charge threshold of the extreme depletion but less than or equal to the state of charge threshold of the allowable pure electric operation, the power battery is preheated according to the second preheating mode. The second preheating mode includes controlling the first multi-way valve to open, the second multi-way valve to open, and controlling the range extender to supply power to the water heater so that the water heater can heat. When the current state of charge of the power battery is greater than the state of charge threshold that allows pure electric operation, the system detects whether the vehicle is in fuel priority mode or electric priority mode. When the vehicle is in the fuel priority mode, the power battery is preheated according to the second preheating mode; When the vehicle is in the power priority mode, the power battery is preheated according to the third preheating mode. The third preheating mode includes controlling both the first multi-way valve and the second multi-way valve to be open, and controlling the range extender to supply power to the water heater so that the water heater can heat.

9. The method of claim 8, wherein, After preheating the power battery according to the second preheating mode, the method further includes: Detect the rate of temperature change in the power battery's circulating water circuit; When the rate of temperature change is less than the lower limit of the preset rate of temperature change, the power battery is preheated according to the third preheating mode until the current temperature of the power battery circulation water circuit exceeds the lower limit threshold. When the rate of temperature change exceeds the upper limit of the preset rate of temperature change, the system enters a fault mode and issues a fault alarm. When the rate of temperature change is between the lower limit and the upper limit of the preset rate of temperature change, the power battery is preheated according to the second preheating mode until the current temperature of the power battery circulation water circuit exceeds the lower limit threshold.

10. A vehicle comprising a thermal management system, characterized in that The thermal management system includes an engine circulating water circuit, a motor circulating water circuit, a power battery circulating water circuit, a first multi-way valve, and a second multi-way valve. The engine circulating water circuit is connected to the motor circulating water circuit through the first multi-way valve to form a circulation loop. The motor circulating water circuit is connected to the power battery circulating water circuit through the second multi-way valve to form a circulation loop. The power battery circulating water circuit includes a water heater for heating the power battery circulating water circuit. The vehicle is used to perform the method according to any one of claims 1-9.

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