A defrosting method for an integrated automotive thermal management system and new energy vehicles

Abstract

This invention belongs to the field of heat pump air conditioning defrosting technology, specifically relating to a defrosting method for an automotive integrated thermal management system and new energy vehicles. The solution includes: a compressor, an in-vehicle heat exchanger, an expansion valve, and an external heat exchanger forming a refrigerant cycle to achieve cooling or heating of the vehicle interior; an energy storage unit cooling heat exchanger cooling the energy storage unit through an energy storage unit cooling cycle; when defrosting the external heat exchanger is required, the target temperature of the cooling cycle heating device is set to a first temperature or a second temperature based on the energy storage unit temperature, with the second temperature being higher than the first temperature; then, the external heat exchanger is used as the condenser side, the energy storage unit cooling heat exchanger as the evaporator side, and the energy storage unit coolant is used as the heat source for defrosting. This defrosting solution achieves precise defrosting without the need for additional auxiliary heating devices and can effectively recover waste heat generated by the battery by exchanging heat between the coolant and refrigerant through the battery cooling heat exchanger, thus saving energy.

Description

Technical Field

[0001] This invention belongs to the field of heat pump air conditioning defrosting technology, specifically relating to a defrosting method for an automotive integrated thermal management system and new energy vehicles. Background Technology

[0002] Energy conservation and emission reduction are the current development trends of the global automotive industry. Against this backdrop, the application of new energy vehicles is becoming increasingly widespread, and many experts and scholars consider it an inevitable path for automotive development. Increased energy consumption and reduced driving range at low temperatures are among the key factors affecting the widespread adoption of electric vehicles. Thermal management systems based on heat pump air conditioning can significantly reduce vehicle energy consumption and extend driving range in low-temperature environments, and have gradually become the mainstream technology in the industry.

[0003] However, when a heat pump air conditioner is running, the outdoor heat exchanger frosts, causing a sharp drop in its heat exchange capacity and a severe reduction in the heat pump's heating capacity, making it unable to operate normally and reliably. To solve this problem, existing technologies mainly use a reverse cycle based on the heat pump system for defrosting. This involves turning on the compressor and using the high-temperature refrigerant at the compressor outlet to enter the frosting heat exchanger for defrosting. However, at the same time, the refrigerant absorbs heat from the vehicle's interior as it passes through the interior heat exchanger, causing the interior temperature to drop and reducing passenger comfort.

[0004] To ensure passenger comfort, maintaining the vehicle's interior temperature is crucial. Chinese invention patent publication number CN107160972A discloses an electric vehicle heat pump air conditioning assembly and its control method, which utilizes a defrosting branch to enhance the defrosting rate and activates an auxiliary heater to compensate for heat loss. Chinese invention patent publication number CN110143112A discloses a defrosting method using a heat accumulator, where the system incorporates a heat accumulator to store heat and compensate for heat loss during defrosting. Chinese utility model patent publication number CN215244231U discloses a defrosting scheme based on an external heater, achieving defrosting through a heating circuit with an independent heater. It is evident that all the above solutions involve additional auxiliary heating devices for defrosting or to compensate for the heat consumed during defrosting, thereby maintaining the vehicle's interior temperature, but this increases system cost and structural complexity. Summary of the Invention

[0005] The purpose of this invention is to propose a defrosting method for an integrated automotive thermal management system, in order to solve the problems of high defrosting cost and complex structure in existing thermal management systems based on heat pump air conditioning. In addition, this invention also provides a new energy vehicle using the above-mentioned defrosting method.

[0006] To solve the above-mentioned technical problems, the solution of the present invention includes:

[0007] This invention discloses a defrosting method for an automotive integrated thermal management system. A refrigerant cycle is sequentially formed by connecting the compressor, in-vehicle heat exchanger, expansion valve, and external heat exchanger to heat the in-vehicle heat exchanger. The compressor, external heat exchanger, expansion valve, and energy storage unit cooling heat exchanger are also sequentially connected to form a refrigerant cycle to cool the energy storage unit cooling heat exchanger. The energy storage unit cooling heat exchanger is used to cool the energy storage unit through the energy storage unit cooling cycle. A cooling cycle heating device is also provided in the energy storage unit cooling cycle for heating the energy storage unit through the cooling cycle.

[0008] When defrosting of the external heat exchanger is required, it is determined whether the energy storage unit temperature has reached the set condition. If the energy storage unit temperature reaches the set condition, the target temperature of the cooling cycle heating device is set as the first temperature. If the energy storage unit temperature does not reach the set condition, the target temperature of the cooling cycle heating device is set as the second temperature, and the second temperature is greater than the first temperature. Then, the external heat exchanger is used as the condenser side and the energy storage unit cooling heat exchanger is used as the evaporator side. The refrigerant circulation is run, and the coolant in the energy storage unit cooling cycle is used as the heat source for defrosting.

[0009] Its beneficial effects are as follows: This invention is based on the linkage defrosting of heat pump and energy storage unit heating. On the one hand, the heat in the heating liquid flow circuit of the energy storage unit is used for heat pump defrosting. During defrosting, there is no need to absorb heat from the vehicle interior, and no need to add auxiliary heating or other devices in the vehicle interior. This effectively solves the problem of increased cost and weight caused by the need for PTC auxiliary heating during traditional defrosting, which requires vehicle interior cooling operation. This reduces system cost and structural complexity. On the other hand, by utilizing the heat transfer between coolant and refrigerant, the heat generated by the energy storage unit is recovered and used for heat pump defrosting. This effectively solves the problem of heat loss from the energy storage unit, thereby achieving energy saving.

[0010] To achieve more precise cooling target temperatures, ensuring that the heat required for defrosting is provided while maintaining the energy storage unit's temperature within its normal operating range, accurate defrosting is achieved. The first temperature is the temperature required to maintain the heat pump's defrosting capability, and the second temperature is the temperature required to both heat the energy storage unit and maintain the heat pump's defrosting capability.

[0011] Furthermore, the compressor outlet is connected to the first port of the four-way valve, and the second and fourth ports of the four-way valve are connected in series with the external radiator, the first expansion valve, and the internal radiator. The third port of the four-way valve is connected to the compressor inlet. The four-way valve can switch between the first port connecting to the second port and the third port connecting to the fourth port, and between the first port connecting to the fourth port and the second port connecting to the third port. The branch where the first expansion valve and the internal heat exchanger are located is also connected in parallel with a branch formed by the second expansion valve and one heat exchange side of the energy storage unit cooling heat exchanger connected in series. The other heat exchange side of the energy storage unit cooling heat exchanger is connected in series in the energy storage unit cooling cycle.

[0012] By switching the connection between the four ports of the four-way valve, the flow direction of the coolant in the coolant circulation loop is adjusted, realizing heat pump cycle and refrigeration cycle. This provides a simple air conditioning system for automotive integrated thermal management systems, with a simple control strategy when used for heat pump defrosting.

[0013] Furthermore, the compressor, in-vehicle condenser, first expansion valve, external heat exchanger, second expansion valve, and in-vehicle heat exchanger are sequentially connected to form a cycle; a first switching valve is connected in series between the outlet of the compressor and the inlet of the external heat exchanger; a second switching valve is connected in series between the outlet of the external heat exchanger and the inlet of the compressor; the branch containing the second expansion valve and the in-vehicle heat exchanger is also connected in parallel to a branch formed by the third expansion valve and the energy storage unit cooling heat exchanger connected in series, and the other heat exchange side of the energy storage unit cooling heat exchanger is connected in series in the energy storage unit cooling cycle.

[0014] The compressor's outlet and inlet are connected in series with an in-vehicle heat exchanger, a first expansion valve, an external heat exchanger, and a second switching valve to form a refrigerant circulation that heats the in-vehicle heat exchanger. The compressor's outlet and inlet are also connected in series with a first switching valve, an external heat exchanger, a second expansion valve, and one heat exchange end of an energy storage unit cooling heat exchanger to form a refrigerant circulation that cools the energy storage unit cooling heat exchanger. The other heat exchange side of the energy storage unit cooling heat exchanger is connected in series in the energy storage unit cooling cycle.

[0015] Furthermore, the energy storage unit cooling cycle includes a water pump, an energy storage unit liquid cooling pipeline, a cooling cycle heating device, and an energy storage unit cooling heat exchanger connected in sequence.

[0016] The present invention discloses a new energy vehicle comprising a compressor, an in-vehicle heat exchanger, an expansion valve, and an external heat exchanger sequentially connected to form a refrigerant cycle to heat the in-vehicle heat exchanger; the compressor, the external heat exchanger, the expansion valve, and an energy storage unit cooling heat exchanger are also sequentially connected to form a refrigerant cycle to cool the energy storage unit cooling heat exchanger, the energy storage unit cooling heat exchanger being used to cool the energy storage unit through the energy storage unit cooling cycle; the energy storage unit cooling cycle also includes a cooling cycle heating device for heating the energy storage unit through the energy storage unit cooling cycle;

[0017] When defrosting of the external heat exchanger is required, it is determined whether the energy storage unit temperature has reached the set condition. If the energy storage unit temperature reaches the set condition, the target temperature of the cooling cycle heating device is set as the first temperature. If the energy storage unit temperature does not reach the set condition, the target temperature of the cooling cycle heating device is set as the second temperature, and the second temperature is greater than the first temperature. Then, the external heat exchanger is used as the condenser side and the energy storage unit cooling heat exchanger is used as the evaporator side. The refrigerant circulation is run, and the coolant in the energy storage unit cooling cycle is used as the heat source for defrosting.

[0018] Its beneficial effects are as follows: This invention is based on the linkage defrosting of heat pump and energy storage unit heating. On the one hand, the heat in the heating liquid flow circuit of the energy storage unit is used for heat pump defrosting. During defrosting, there is no need to absorb heat from the vehicle interior, and no need to add auxiliary heating or other devices in the vehicle interior. This effectively solves the problem of increased cost and weight caused by the need for PTC auxiliary heating during traditional defrosting, which requires vehicle interior cooling operation. This reduces system cost and structural complexity. On the other hand, by utilizing the heat transfer between coolant and refrigerant, the heat generated by the energy storage unit is recovered and used for heat pump defrosting. This effectively solves the problem of heat loss from the energy storage unit, thereby achieving energy saving.

[0019] To achieve more precise cooling target temperatures, ensuring that the heat required for defrosting is provided while maintaining the energy storage unit's temperature within its normal operating range, accurate defrosting is achieved. The first temperature is the temperature required to maintain the heat pump's defrosting capability, and the second temperature is the temperature required to both heat the energy storage unit and maintain the heat pump's defrosting capability.

[0020] Furthermore, the compressor outlet is connected to the first port of the four-way valve, and the second and fourth ports of the four-way valve are connected in series with the external radiator, the first expansion valve, and the internal radiator. The third port of the four-way valve is connected to the compressor inlet. The four-way valve can switch between the first port connecting to the second port and the third port connecting to the fourth port, and between the first port connecting to the fourth port and the second port connecting to the third port. The branch where the first expansion valve and the internal heat exchanger are located is also connected in parallel with a branch formed by the second expansion valve and one heat exchange side of the energy storage unit cooling heat exchanger connected in series. The other heat exchange side of the energy storage unit cooling heat exchanger is connected in series in the energy storage unit cooling cycle.

[0021] By switching the connection between the four ports of the four-way valve, the flow direction of the coolant in the coolant circulation loop is adjusted, realizing heat pump cycle and refrigeration cycle. This provides a simple air conditioning system for automotive integrated thermal management systems, with a simple control strategy when used for heat pump defrosting.

[0022] Furthermore, the compressor, in-vehicle condenser, first expansion valve, external heat exchanger, second expansion valve, and in-vehicle heat exchanger are sequentially connected to form a cycle; a first switching valve is connected in series between the outlet of the compressor and the inlet of the external heat exchanger; a second switching valve is connected in series between the outlet of the external heat exchanger and the inlet of the compressor; the branch containing the second expansion valve and the in-vehicle heat exchanger is also connected in parallel to a branch formed by the third expansion valve and the energy storage unit cooling heat exchanger connected in series, and the other heat exchange side of the energy storage unit cooling heat exchanger is connected in series in the energy storage unit cooling cycle.

[0023] The compressor's outlet and inlet are connected in series with an in-vehicle heat exchanger, a first expansion valve, an external heat exchanger, and a second switching valve to form a refrigerant circulation that heats the in-vehicle heat exchanger. The compressor's outlet and inlet are also connected in series with a first switching valve, an external heat exchanger, a second expansion valve, and one heat exchange end of an energy storage unit cooling heat exchanger to form a refrigerant circulation that cools the energy storage unit cooling heat exchanger. The other heat exchange side of the energy storage unit cooling heat exchanger is connected in series in the energy storage unit cooling cycle.

[0024] Furthermore, the energy storage unit cooling cycle includes a water pump, an energy storage unit liquid cooling pipeline, a cooling cycle heating device, and an energy storage unit cooling heat exchanger connected in sequence. Attached Figure Description

[0025] Figure 1 This is a flowchart of the defrosting control logic of the thermal management system in Embodiment 1 of the present invention;

[0026] Figure 2 This is a structural diagram of a thermal management system based on a four-way valve, as shown in Example 2.

[0027] Figure 3(a) is a schematic diagram of the interface of the four-way valve 21 in Example 2;

[0028] Figure 3(b) is a schematic diagram of the interface of the battery cooling heat exchanger 5 in Examples 2 and 3;

[0029] Figure 4 This is a flowchart of the defrosting control logic of Embodiment 2 of the present invention;

[0030] Figure 5 This is a structural diagram of a thermal management system based on a three-heat exchanger, as described in Example 3.

[0031] Figure 6 This is a flowchart of the defrosting control logic of Embodiment 3 of the present invention.

[0032] The diagram includes: 1-compressor; 2-external heat exchanger; 3-first expansion valve; 4-second expansion valve; 5-battery cooling heat exchanger; 6-water pump; 7-battery; 8-coolant heater; 21-four-way valve; 22-internal heat exchanger; 31-internal condenser; 32-third expansion valve; 33-first solenoid valve; 34-second solenoid valve; 35-internal evaporator. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical principles and practical applications of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0034] Method Example 1:

[0035] The automotive integrated thermal management system is used to cool and heat the passenger compartment, and it can also cool the battery. When cooling the battery, the temperature of the battery coolant is transferred to the refrigerant through a plate heat exchanger, thereby reducing the temperature of the battery coolant. This is then achieved through a battery cooling cycle, which further reduces the battery temperature.

[0036] The integrated thermal management system consists of a compressor, expansion valve, external heat exchanger, internal heat exchanger, water pump, battery liquid cooling piping, coolant heater, and battery cooling heat exchanger. The compressor, external heat exchanger, expansion valve, and internal heat exchanger are connected to form the air conditioning circuit, while the compressor, internal heat exchanger, expansion valve, and external heat exchanger are also connected to form the heat pump air conditioning circuit. In addition to cooling the vehicle interior, the air conditioning system also cools the battery coolant circuit. The internal heat exchanger is connected in parallel with the battery cooling heat exchanger. In the coolant circuit, the water pump outlet is connected to the battery liquid cooling inlet, the battery liquid cooling outlet is connected to the coolant heater inlet, the coolant heater outlet is connected to one port on the other side of the battery cooling heat exchanger, and the other port on the other side of the battery cooling heat exchanger is connected to the water pump inlet, forming a coolant circulation loop.

[0037] When the vehicle is in heating mode, and the system enters defrost mode, it activates the battery coolant circulation, utilizing the high-temperature refrigerant from the compressor outlet for defrosting. Simultaneously, it absorbs heat from the battery coolant circulation loop and controls the operating modes of the coolant and refrigerant sides based on the battery and coolant temperatures to ensure the coolant temperature remains within a suitable range. The defrost control logic of the thermal management system is detailed below. Figure 1 The specific steps are as follows:

[0038] Step 1: Determine if the heat pump air conditioner has reached the defrosting condition. If it has, proceed to Step 2; otherwise, maintain the current operating mode and return to Step 1. The defrosting condition refers to the driver needing to defrost the external heat exchanger by sensing the temperature inside the vehicle and turning on the defrost button, or the defrosting detection device automatically adjusting to the defrosting mode by detecting the need for defrosting through a temperature sensor installed near the external heat exchanger.

[0039] Step 2: Determine if the battery temperature Tb has reached the battery temperature threshold T1 (T1 refers to the lowest critical value for the battery temperature to be within the normal range, called the battery temperature threshold). If Tb ≥ T1, it means that the battery no longer needs heating. At this time, set the target temperature of the coolant to the first temperature T2 (T2 refers to the average temperature required to maintain heat pump defrosting based on the test results of the vehicle under different operating conditions, called the first temperature), and then proceed to step 3; if Tb < T1, it means that the battery needs heating. At this time, set the target temperature of the coolant to the second temperature T3 (T3 refers to the average temperature required to simultaneously achieve battery heating and maintain heat pump defrosting based on the test results of the vehicle under different operating conditions, called the second temperature, usually T3 > T2), and then proceed to step 4.

[0040] Step 3: Detect the coolant temperature Tc and determine the relationship between Tc and T2. If Tc < T2, turn on both the water pump and the coolant heater simultaneously; if Tc ≥ T2, turn on the water pump and turn off the coolant heater; then proceed to step 5.

[0041] Step 4: Detect the coolant temperature Tc and determine the relationship between Tc and T3. If Tc < T3, turn on both the water pump and the coolant heater simultaneously; if Tc ≥ T3, turn on the water pump and turn off the coolant heater; then proceed to Step 5.

[0042] Step 5: Using the battery cooling heat exchanger as the evaporation side and the external heat exchanger as the condensation side, run the heat pump system and use the battery coolant as the heat source for heat pump defrosting.

[0043] Method Example 2:

[0044] like Figure 2 The image shows a thermal management system for a new energy vehicle based on a four-way valve.

[0045] The system includes a refrigerant side and a coolant side. The refrigerant side, via compressor 1, four-way valve 21, external heat exchanger 2, first expansion valve 3, internal heat exchanger 22, second expansion valve 4, and battery cooling heat exchanger 5, constitutes both a refrigeration air conditioner and a heat pump air conditioner. The four-way valve 21 switches the refrigerant flow direction to achieve the conversion between refrigeration and heat pump operation. As shown in Figure 3(a), the four-way valve 21 has four ports: A, B, C, and D, and can switch between connecting port A to port B and port C to port D, and between connecting port A to port D and port B to port C. The outlet of compressor 1 is connected to port A of four-way valve 21, port B of four-way valve 21 is connected to the inlet of external heat exchanger 2, the outlet of external heat exchanger 2 is connected to the inlet of internal heat exchanger 22 through first expansion valve 3, the outlet of internal heat exchanger 22 is connected to port D of four-way valve 21, and port C of four-way valve 21 is connected to the inlet of compressor 1 to form an air conditioning circulation loop. The first expansion valve 3 and internal heat exchanger 22 are connected in series to form a refrigeration air conditioning branch. The outlet of compressor 1 is connected to port A of four-way valve 21, port D of four-way valve 21 is connected to the inlet of internal heat exchanger 22, the outlet of internal heat exchanger 22 is connected to the inlet of external heat exchanger 2 through first expansion valve 3, the outlet of external heat exchanger 2 is connected to port B of four-way valve 21, and port C of four-way valve 21 is connected to the inlet of compressor 1 to form a heat pump circulation loop.

[0046] Coolant side: A coolant circulation loop is formed by water pump 6, battery liquid cooling pipeline 7, coolant heater 8, and battery cooling heat exchanger 5. As shown in Figure 3(b), the battery cooling heat exchanger 5 has four ports: A, B, C, and D. Ports A and B are connected to form the first heat exchange side, which is connected in parallel with the refrigeration / air conditioning branch. Ports C and D are connected to form the second heat exchange side, which is connected in series in the coolant circulation loop. Refrigerant and coolant exchange heat through the first and second heat exchange sides of the battery cooling heat exchanger 5, respectively. The outlet of water pump 6 is connected to the inlet of battery liquid cooling pipeline 7, the outlet of battery liquid cooling pipeline 7 is connected to the inlet of coolant heater 8, the outlet of coolant heater 8 is connected to port D of the second heat exchange side of battery cooling heat exchanger 5, and port C of the second heat exchange side of battery cooling heat exchanger 5 is connected to the inlet of water pump 6, thus forming the coolant circulation loop.

[0047] When defrosting is required, the four-way valve is switched so that port A connects to port B and port C connects to port D. Simultaneously, the external heat exchanger 2 operates in condensation mode, the battery cooling heat exchanger 5 operates in evaporation mode, and the air conditioning circulation is activated. The air conditioning circulation on the refrigerant side and the coolant circulation loop exchange heat through the battery cooling heat exchanger 5, transferring heat from the coolant side to the refrigerant side to achieve defrosting. When the coolant heater 8 in the coolant circulation loop is off, the defrosting process also achieves battery cooling; when the coolant heater 8 in the coolant circulation loop is on, defrosting is performed while maintaining the battery temperature.

[0048] like Figure 4 The diagram shows the defrosting control logic of a thermal management system based on a four-way valve. The main operating modes are as follows:

[0049] Mode 1: If the battery temperature Tb is greater than or equal to the battery temperature threshold T1, then set the target coolant temperature to the first temperature T2. Detect the coolant temperature Tc and determine the relationship between Tc and T2. If Tc < T2, then simultaneously activate the water pump 6 and the coolant heater 8.

[0050] Mode 2: If the battery temperature Tb is greater than or equal to the battery temperature threshold T1, then set the target coolant temperature to the first temperature T2. Detect the coolant temperature Tc and determine the relationship between Tc and T2. If Tc ≥ T2, then turn on the water pump 6 and turn off the coolant heater 8.

[0051] Mode 3: If the battery temperature Tb is less than the battery temperature threshold T1, then set the target coolant temperature to the second temperature T3. Detect the coolant temperature Tc and determine the relationship between Tc and T3. If Tc < T3, then simultaneously activate the water pump 6 and the coolant heater 8.

[0052] Mode 4: If the battery temperature Tb is less than the battery temperature threshold T1, then set the target coolant temperature to the second temperature T3. Detect the coolant temperature Tc and determine the relationship between Tc and T3. If Tc ≥ T3, then turn on the water pump 6 and turn off the coolant heater 8.

[0053] In all four operating modes, compressor 1 is turned on, ports A and B of four-way valve 21 are connected, ports C and D are connected, the first expansion valve 3 is closed, the second expansion valve 4 is opened, the battery cooling heat exchanger 5 is used as the evaporation side, the external heat exchanger 2 is used as the condensation side, the heat pump system is run, and the battery coolant is used as the heat source for defrosting.

[0054] Method Example 3:

[0055] like Figure 5 The diagram shows a thermal management system based on a three-heat-exchanger system:

[0056] The system includes a refrigerant side and a coolant side. The refrigerant side, via compressor 1, first solenoid valve 33, in-vehicle condenser 31, first expansion valve 3, external heat exchanger 2, second solenoid valve 34, in-vehicle evaporator 35, second expansion valve 4, third expansion valve 32, and battery cooling heat exchanger 5, constitutes a refrigeration air conditioner and a heat pump air conditioner. The refrigerant flow is regulated by the alternating or combined connection of the in-vehicle condenser 13, external heat exchanger 2, and in-vehicle evaporator 35, forming the refrigerant circuit for either the refrigeration air conditioner or the heat pump air conditioner. In addition to cooling the vehicle interior, the refrigeration air conditioner also cools the battery coolant circuit; the battery cooling heat exchanger is connected in parallel to the in-vehicle evaporator. Specifically, the outlet of compressor 1 is connected to the inlet of the external heat exchanger 2 via the first solenoid valve 33, and the outlet of the external heat exchanger 2 is connected to the inlet of the internal evaporator 35 via the second expansion valve 4. The outlet of the internal evaporator 35 and the inlet of compressor 1 are connected to form an air conditioning circulation loop. The second expansion valve 4 and the internal heat exchanger 35 are connected in series to form a refrigeration air conditioning branch. The outlet of compressor 1 is connected to the inlet of the internal condenser 31, and the outlet of the internal condenser 31 is connected to the inlet of the external heat exchanger 2 via the first expansion valve 3. The outlet of the external heat exchanger 2 and the inlet of compressor 1 are connected to the inlet of compressor 1 via the second solenoid valve 34 to form a heat pump circulation loop. The outlet of compressor 1 and the inlet of internal condenser 31 are connected to the inlet of external heat exchanger 2 via the first expansion valve 3. The outlet of external heat exchanger 2 and the inlet of internal evaporator 35 are connected to the inlet of compressor 1 via the second expansion valve 4 to form a demisting circulation loop.

[0057] Coolant side: A coolant circulation loop is formed by water pump 6, battery liquid cooling pipeline 7, coolant heater 8, and battery cooling heat exchanger 5. The outlet of water pump 6 is connected to the inlet of battery liquid cooling pipeline 7, the outlet of battery liquid cooling pipeline 7 is connected to the inlet of coolant heater 8, the outlet of coolant heater 8 is connected to port D of battery cooling heat exchanger 5, and port C of battery cooling heat exchanger 5 is connected to the inlet of water pump 6, thus forming the coolant circulation loop. The other heat exchange side (i.e., the refrigerant side) of battery cooling heat exchanger 5 is connected in parallel with the refrigeration and air conditioning branch.

[0058] When defrosting is required, the first solenoid valve 33 is opened and the second solenoid valve 34 is closed. Simultaneously, the external heat exchanger 2 operates in condensation mode, the battery cooling heat exchanger 5 operates in evaporation mode, and the air conditioning circulation is activated. The air conditioning circulation on the refrigerant side and the coolant circulation loop exchange heat through the battery cooling heat exchanger 5, transferring heat from the coolant side to the refrigerant side to achieve defrosting. When the coolant heater 8 in the coolant circulation loop is closed, the defrosting process also achieves battery cooling; when the coolant heater 8 in the coolant circulation loop is open, defrosting is performed while maintaining the battery temperature.

[0059] like Figure 6The diagram shows the defrosting control logic of a thermal management system based on a three-heat-exchanger system. The main operating modes are as follows:

[0060] Mode 1: If the battery temperature Tb is greater than or equal to the battery temperature threshold T1, then set the target coolant temperature to the first temperature T2. Detect the coolant temperature Tc and determine the relationship between Tc and T2. If Tc < T2, then simultaneously activate the water pump 6 and the coolant heater 8.

[0061] Mode 2: If the battery temperature Tb is greater than or equal to the battery temperature threshold T1, then set the target coolant temperature to the first temperature T2. Detect the coolant temperature Tc and determine the relationship between Tc and T2. If Tc ≥ T2, then turn on the water pump 6 and turn off the coolant heater 8.

[0062] Mode 3: If the battery temperature Tb is less than the battery temperature threshold T1, then set the target coolant temperature to the second temperature T3. Detect the coolant temperature Tc and determine the relationship between Tc and T3. If Tc < T3, then simultaneously activate the water pump 6 and the coolant heater 8.

[0063] Mode 4: If the battery temperature Tb is less than the battery temperature threshold T1, then set the target coolant temperature to the second temperature T3. Detect the coolant temperature Tc and determine the relationship between Tc and T3. If Tc ≥ T3, then turn on the water pump 6 and turn off the coolant heater 8.

[0064] In all four operating modes, compressor 1 is turned on, first solenoid valve 33 is turned on, first expansion valve 3, second solenoid valve 34 and second expansion valve 4 are turned off, third expansion valve 32 is turned on, battery cooling heat exchanger 5 is used as the evaporation side and external heat exchanger 2 is used as the condensation side, the heat pump system is run, and battery coolant is used as the heat source for defrosting.

[0065] This invention is based on a set battery temperature threshold T1, a first temperature T2, and a second temperature T3, as well as the magnitude discrimination relationship between the three, to divide different working modes. According to different working modes, the water pump and coolant heater are controlled to turn on or off. The control valves, such as solenoid valves and expansion valves, control the opening and closing of the heat exchanger, condenser, and evaporator to make the battery cooling heat exchanger the evaporation side and the external heat exchanger the condensation side, so as to run the heat pump system and use the battery coolant as the heat source for defrosting.

[0066] During the defrosting process, not only can the heat required for defrosting be supplemented by the coolant heater, but there is also no need to absorb heat from the vehicle interior during defrosting, nor is it necessary to add auxiliary heating or other devices to the vehicle interior. This effectively simplifies the system and reduces system costs. Furthermore, it can effectively recover the heat generated by the battery by using the heat transfer between the coolant and the refrigerant for heat exchange. The excess heat beyond the heat required to maintain normal battery operation is recovered and used for heat pump defrosting, thereby achieving energy saving.

[0067] The present invention provides a method for defrosting a heat pump air conditioner using the energy of a battery coolant circulation system. Regardless of how the system configuration evolves, any method that uses the above-mentioned control mode to generate heat from the coolant heater or to generate heat from the battery and the coolant heater for defrosting is within the scope of protection of the present invention.

[0068] Examples of new energy vehicles:

[0069] The new energy vehicle of the present invention includes an integrated thermal management system, which comprises a compressor, an expansion valve, an external heat exchanger, an internal heat exchanger, and a battery liquid cooling cycle, forming a heat pump cycle and a refrigeration cycle, capable of cooling and heating the vehicle interior and cooling the battery liquid cooling cycle. The integrated thermal management system of the new energy vehicle of the present invention can utilize the battery liquid cooling cycle to defrost the external heat exchanger. The specific structure and defrosting method of the integrated thermal management system have been sufficiently described in Method Examples 1 to 3, and will not be repeated here.

Claims

1. A defrosting method for an automotive integrated thermal management system, characterized in that, The compressor, in-vehicle heat exchanger, expansion valve, and external heat exchanger are sequentially connected to form a refrigerant circulation to heat the in-vehicle heat exchanger; the compressor, external heat exchanger, expansion valve, and the refrigerant side of the energy storage unit cooling heat exchanger are also sequentially connected to form a refrigerant circulation to cool the energy storage unit cooling heat exchanger; the coolant side of the energy storage unit cooling heat exchanger, together with the water pump and energy storage unit cooling pipes, forms an energy storage unit cooling circulation to cool the energy storage unit; a cooling circulation heating device is also provided in the energy storage unit cooling circulation to heat the energy storage unit; When defrosting of the external heat exchanger is required, the energy storage unit cooling cycle is activated, and it is determined whether the energy storage unit temperature has reached the set condition. If the energy storage unit temperature reaches the set condition, the target temperature of the cooling cycle heating device is set to the first temperature. If the coolant temperature is lower than the first temperature, the cooling cycle heating device is activated; otherwise, it is not activated. If the energy storage unit temperature has not reached the set condition, the target temperature of the cooling cycle heating device is set to the second temperature. If the coolant temperature is lower than the second temperature, the cooling cycle heating device is activated; otherwise, it is not activated, and the second temperature is higher than the first temperature. Then, the external heat exchanger is used as the condenser side, and the energy storage unit cooling heat exchanger is used as the evaporator side. The refrigerant circulation is run, and the coolant in the energy storage unit cooling cycle is used as the heat source for defrosting.

2. The defrosting method for an automotive integrated thermal management system according to claim 1, characterized in that, The first temperature is the temperature required to maintain the defrosting of the heat pump, and the second temperature is the temperature required to heat the energy storage unit and maintain the defrosting of the heat pump.

3. The defrosting method for an automotive integrated thermal management system according to claim 1, characterized in that, The compressor outlet is connected to the first port of the four-way valve. The second and fourth ports of the four-way valve are connected in series with the external radiator, the first expansion valve, and the internal radiator. The third port of the four-way valve is connected to the compressor inlet. The four-way valve can switch between the first port connecting to the second port and the third port connecting to the fourth port, and between the first port connecting to the fourth port and the second port connecting to the third port. The branch where the first expansion valve and the internal heat exchanger are located is also connected in parallel with a branch formed by the second expansion valve and one heat exchange side of the energy storage unit cooling heat exchanger connected in series. The other heat exchange side of the energy storage unit cooling heat exchanger is connected in series in the energy storage unit cooling cycle.

4. The defrosting method for an automotive integrated thermal management system according to claim 1, characterized in that, The compressor, in-vehicle condenser, first expansion valve, external heat exchanger, second expansion valve, and in-vehicle heat exchanger are sequentially connected to form a cycle. A first switching valve is connected in series between the outlet of the compressor and the inlet of the external heat exchanger. A second switching valve is also connected in series between the outlet of the external heat exchanger and the inlet of the compressor. The branch containing the second expansion valve and the in-vehicle heat exchanger is also connected in parallel to a branch formed by the third expansion valve and the energy storage unit cooling heat exchanger connected in series. The other heat exchange side of the energy storage unit cooling heat exchanger is connected in series in the energy storage unit cooling cycle.

5. The defrosting method for an automotive integrated thermal management system according to claim 3 or 4, characterized in that, The energy storage unit cooling cycle includes a water pump, an energy storage unit liquid cooling pipeline, a cooling cycle heating device, and an energy storage unit cooling heat exchanger connected in sequence.

6. A new energy vehicle, characterized in that, The system includes a refrigerant cycle consisting of a compressor, an in-vehicle heat exchanger, an expansion valve, and an external heat exchanger, which provides heating to the in-vehicle heat exchanger; and a refrigerant cycle consisting of a compressor, an external heat exchanger, an expansion valve, and the refrigerant side of the energy storage unit cooling heat exchanger, which provides cooling to the energy storage unit cooling heat exchanger. The coolant side of the energy storage unit cooling heat exchanger, together with the water pump and the energy storage unit cooling pipes, forms an energy storage unit cooling cycle to cool the energy storage unit. The energy storage unit cooling cycle also includes a cooling cycle heating device to heat the energy storage unit. When defrosting of the external heat exchanger is required, the energy storage unit cooling cycle is activated, and it is determined whether the energy storage unit temperature has reached the set condition. If the energy storage unit temperature reaches the set condition, the target temperature of the cooling cycle heating device is set to the first temperature. If the coolant temperature is lower than the first temperature, the cooling cycle heating device is activated; otherwise, it is not activated. If the energy storage unit temperature has not reached the set condition, the target temperature of the cooling cycle heating device is set to the second temperature. If the coolant temperature is lower than the second temperature, the cooling cycle heating device is activated; otherwise, it is not activated, and the second temperature is higher than the first temperature. Then, the external heat exchanger is used as the condenser side, and the energy storage unit cooling heat exchanger is used as the evaporator side. The refrigerant circulation is run, and the coolant in the energy storage unit cooling cycle is used as the heat source for defrosting.

7. The new energy vehicle according to claim 6, characterized in that, The first temperature is the temperature required to maintain the defrosting of the heat pump, and the second temperature is the temperature required to heat the energy storage unit and maintain the defrosting of the heat pump.

8. The new energy vehicle according to claim 6, characterized in that, The compressor outlet is connected to the first port of the four-way valve. The second and fourth ports of the four-way valve are connected in series with the external radiator, the first expansion valve, and the internal radiator. The third port of the four-way valve is connected to the compressor inlet. The four-way valve can switch between the first port connecting to the second port and the third port connecting to the fourth port, and between the first port connecting to the fourth port and the second port connecting to the third port. The branch where the first expansion valve and the internal heat exchanger are located is also connected in parallel with a branch formed by the second expansion valve and one heat exchange side of the energy storage unit cooling heat exchanger connected in series. The other heat exchange side of the energy storage unit cooling heat exchanger is connected in series in the energy storage unit cooling cycle.

9. The new energy vehicle according to claim 6, characterized in that, The compressor, in-vehicle condenser, first expansion valve, external heat exchanger, second expansion valve, and in-vehicle heat exchanger are sequentially connected to form a cycle. A first switching valve is connected in series between the outlet of the compressor and the inlet of the external heat exchanger. A second switching valve is also connected in series between the outlet of the external heat exchanger and the inlet of the compressor. The branch containing the second expansion valve and the in-vehicle heat exchanger is also connected in parallel to a branch formed by the third expansion valve and the energy storage unit cooling heat exchanger connected in series. The other heat exchange side of the energy storage unit cooling heat exchanger is connected in series in the energy storage unit cooling cycle.

10. The new energy vehicle according to claim 8 or 9, characterized in that, The energy storage unit cooling cycle includes a water pump, an energy storage unit liquid cooling pipeline, a cooling cycle heating device, and an energy storage unit cooling heat exchanger connected in sequence.

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