A new energy electric vehicle low-temperature heat pump cooling and heating system and its control method

Abstract

The present invention discloses a low-temperature heat pump cooling and heating system for a new energy electric vehicle and a control method thereof, comprising a compressor; the high-temperature and high-pressure refrigerant outlet of the compressor is connected to the fourth interface of a four-way valve; the second interface of the four-way valve is connected to the refrigerant inlet of the compressor; the third interface is connected to the refrigerant inlet in the middle of the compressor via a liquid storage tank, a first electronic expansion valve, and a flash evaporator in sequence; the first interface is connected to the liquid storage tank via an off-board heat exchanger, a second electronic expansion valve, and a flash evaporator in sequence; the battery-side heat exchanger and the on-board heat exchanger are connected in parallel and then connected to the pipeline between the third interface and the liquid storage tank. The purpose of the present invention is to achieve the integration of in-vehicle air conditioning comfort cooling / heating, battery pack cooling / heating, and frequency conversion technology, and to control the air conditioning mode (cooling / heating) and battery pack (cooling / heating) through the vehicle control system.

Description

Technical Field

[0001] The present invention relates to the technical field of heat pump air conditioning for new energy electric vehicles, and in particular to a low-temperature heat pump heating and cooling system for new energy electric vehicles, which is particularly suitable for winter heating and preventing battery overheating during intense winter driving, and a control method thereof. Background Art

[0002] Patent specification CN 113928077 A discloses a heat pump air conditioning system for electric vehicles, comprising: a first external heat exchanger, a first air supply compressor, a first four-way valve, a first internal heat exchanger, an air supply evaporator, and a temperature control module. The air supply evaporator is connected to the first external heat exchanger, which is connected to the first air supply compressor via the first four-way valve, and the first air supply compressor is connected to the air supply evaporator. The air supply evaporator, the first internal heat exchanger, the first four-way valve, and the first air supply compressor are sequentially connected, and the temperature control module and the air supply evaporator form a cooling circuit. The electric vehicle heat pump air conditioning system provided by this patented technology can switch between cooling and heating modes and effectively recover waste heat generated by components such as the battery and motor, improving the system's cooling efficiency and heating performance at lower ambient temperatures.

[0003] Patent specification CN 114801891 A discloses a multifunctional battery thermal management system and its operating method, comprising an air conditioning system and a battery module. The air conditioning system is connected to the battery module via a master switch and a throttle valve connected in sequence. The air conditioning system includes a gas tank connected to the master switch. The battery module includes multiple battery branches, each of which includes multiple batteries connected in sequence, each connected to a nozzle. A branch temperature-sensing valve is provided between each battery branch and the throttle valve. This patented technology incorporates temperature-sensing valves, gas tanks, and nozzles. This multifunctional system not only meets the cooling or heating requirements of electric vehicles, but also utilizes the inherently non-flammable nature of the working fluid and its rapid temperature drop after passing through the throttle valve to achieve a cooling effect on the battery, while also providing flame retardancy and explosion-proof properties under extreme conditions.

[0004] With the rapid adoption of new energy vehicles, winter heating and battery insulation consume significant amounts of electricity, significantly reducing range. Furthermore, efforts are underway to improve cooling efficiency for batteries that heat up during summer heat or during intense driving, while also considering the potential flammability and explosion hazards posed by damaged batteries. Summary of the Invention

[0005] In response to the above-mentioned technical problems and the shortcomings in this field, the present invention provides a new energy electric vehicle low-temperature heat pump heating and cooling system and a control method thereof, the purpose of which is to realize the integration of in-vehicle air-conditioning comfortable cooling / heating, battery pack cooling / heating, frequency conversion technology, etc., and to perform air-conditioning mode (cooling / heating) and battery pack (cooling / heating) through the vehicle control system.

[0006] The specific technical solutions are as follows:

[0007] A low-temperature heat pump cooling and heating system for a new energy electric vehicle, comprising a compressor;

[0008] The high-temperature and high-pressure refrigerant outlet of the compressor is connected to the fourth interface of the four-way valve;

[0009] The second interface of the four-way valve is connected to the refrigerant inlet of the compressor. The third interface is connected to the refrigerant inlet in the middle of the compressor through the liquid storage tank, the first electronic expansion valve, and the flash evaporator in sequence. The first interface is connected to the liquid storage tank through the vehicle's outer heat exchanger, the second electronic expansion valve, and the flash evaporator in sequence.

[0010] The battery side heat exchanger and the vehicle interior side heat exchanger are connected in parallel and connected to the pipeline between the third interface and the liquid storage tank.

[0011] In a preferred example, in the low-temperature heat pump cooling and heating system of the new energy electric vehicle, a filter is provided on the pipeline between the liquid storage tank and the first electronic expansion valve and the flash evaporator.

[0012] In a preferred example, in the low-temperature heat pump cooling and heating system of the new energy electric vehicle, a gas-liquid separator is provided on the pipeline between the second interface and the refrigerant inlet of the compressor.

[0013] In a preferred example, in the low-temperature heat pump cooling and heating system of the new energy electric vehicle, a waste heat recovery device connected to the electric drive is provided on the pipeline between the flash evaporator and the refrigerant inlet in the middle of the compressor. When the refrigerant in the pipeline flows through the waste heat recovery device, it can absorb the heat generated by the electric drive and heat up, thereby promoting the heat dissipation of the electric drive while reducing the load of the compressor.

[0014] In a preferred embodiment, the low-temperature heat pump cooling and heating system of the new energy electric vehicle, the battery side heat exchanger is connected with the circulation pump, the multi-channel distributor and the oil-immersed integral battery pack to form a heat exchange medium circulation loop;

[0015] In the oil-immersed integral battery pack, the gap between the battery pack and the battery outer shell is filled with the heat exchange medium, and the battery pack is immersed in the heat exchange medium;

[0016] The battery outer shell is provided with multiple heat exchange medium circulation ports connected in parallel and connected to a multi-channel distributor. Each heat exchange medium circulation port is provided with a temperature probe and a heat exchange medium flow control valve; the heat exchange medium flow control valve can adjust the heat exchange medium flow according to the temperature detected by the corresponding temperature probe to accurately control the battery temperature in the corresponding area.

[0017] In a preferred example, in the low-temperature heat pump cooling and heating system of the new energy electric vehicle, a safety valve that can release pressure in time is provided on the heat exchange medium circulation loop.

[0018] In a preferred example, in the low-temperature heat pump heating and cooling system of the new energy electric vehicle, the heat exchange medium circulation loop is provided with an expansion tank that can adapt to the volume change of the heat exchange medium due to thermal expansion and contraction.

[0019] In a preferred example, in the low-temperature heat pump cooling and heating system of the new energy electric vehicle, the heat exchange medium is insulating transformer oil.

[0020] In a preferred embodiment, the low-temperature heat pump cooling and heating system of the new energy electric vehicle is provided with an overheat recovery device on the pipeline between the first interface and the vehicle-side heat exchanger; a heat exchange medium pipeline is provided in the overheat recovery device, one end of the heat exchange medium pipeline is connected to the pipeline between the battery-side heat exchanger and the circulation pump through a three-way valve, and the other end is connected to the pipeline between the battery-side heat exchanger and the oil-immersed integral battery pack; the overheat recovery device is connected to the three-way valve, the circulation pump, the multi-channel distributor and the oil-immersed integral battery pack to form a battery overheat circulation loop;

[0021] Under normal circumstances, the three-way valve connects the battery side heat exchanger and the circulation pump;

[0022] When the battery overheats due to long-term operation or intense driving in winter, the three-way valve connects the overheat recovery device and the circulation pump. When the overheated heat exchange medium flows through the heat recovery device through the battery overheat circulation loop, it heats the refrigerant in the pipeline between the first interface and the heat exchanger outside the vehicle while cooling itself, thereby promoting battery heat dissipation, reducing the compressor load, and improving the energy efficiency of the system.

[0023] The present invention also provides a control method for the low-temperature heat pump cooling and heating system of the new energy electric vehicle, comprising:

[0024] 1) Winter heating mode:

[0025] The first port of the four-way valve is connected to the second port, and the third port is connected to the fourth port;

[0026] The compressor, the fourth interface, the third interface, the battery-side heat exchanger, the in-vehicle heat exchanger, the liquid storage tank, the first electronic expansion valve, the flash evaporator, and the refrigerant inlet in the middle of the compressor form a first refrigerant circulation loop;

[0027] The compressor, the fourth interface, the third interface, the battery-side heat exchanger, the in-vehicle heat exchanger, the liquid storage tank, the flash evaporator, the second electronic expansion valve, the out-vehicle heat exchanger, the first interface, the second interface, and the refrigerant inlet of the compressor form a second refrigerant circulation loop;

[0028] The refrigerant in the first refrigerant circulation loop and the refrigerant in the second refrigerant circulation loop perform heat exchange in the flash evaporator. The specific process is as follows:

[0029] In the first refrigerant circulation loop and the second refrigerant circulation loop, the high-temperature and high-pressure refrigerant coming out of the compressor heats the battery and the interior environment while cooling itself when flowing through the battery-side heat exchanger and the vehicle-side heat exchanger. The refrigerant in the pipeline is divided into two paths after passing through the liquid storage tank. The refrigerant in the first refrigerant circulation loop that is further cooled after being reduced in pressure by the first electronic expansion valve absorbs the heat of the refrigerant in the second refrigerant circulation loop when flowing through the flash evaporator, so that the refrigerant in the second refrigerant circulation loop is cooled and then reduced in pressure by the second electronic expansion valve to obtain a lower temperature, so that it can more effectively absorb heat from the outside air when flowing through the vehicle-side heat exchanger. The refrigerant in the first refrigerant circulation loop enters the compressor through the refrigerant inlet in the middle of the compressor after being heated by the flash evaporator, which can reduce the load of the compressor;

[0030] 2) Summer cooling mode:

[0031] The first electronic expansion valve and flash evaporator are always closed;

[0032] The first port of the four-way valve is connected to the fourth port, and the second port is connected to the third port;

[0033] The high-temperature and high-pressure refrigerant coming out of the compressor dissipates heat to the outside air and cools down when flowing through the heat exchanger outside the vehicle. Then, it is further cooled after being depressurized by the second electronic expansion valve to form a low-temperature and low-pressure refrigerant. Then, when flowing through the heat exchanger on the battery side and the heat exchanger inside the vehicle, heat exchange is carried out to provide cooling for the battery and the interior environment while heating itself. Finally, it passes through the third interface, the second interface, and the refrigerant inlet in sequence and returns to the compressor for the next cycle.

[0034] The beneficial effects of the present invention are:

[0035] The heat pump unit employed in this invention overcomes the extreme difficulty of operating in ultra-low temperature environments (-30°C), providing heat and cooling for the vehicle's air conditioner. The development of an immersive, integrated battery assembly completely resolves issues such as battery heating, cooling, insulation, and explosion. The entire system will be equipped with comprehensive, advanced control technology, centrally and effectively managing both the comfort cooling and heating of the vehicle's air conditioner and the cooling and heating of the battery pack. Frequency conversion technology will rationally regulate energy consumption in each zone, significantly reducing the cooling and heating loads of each component and significantly improving the vehicle's range.

[0036] The system of the present invention is equipped with a flash evaporator. On the one hand, it supercools the refrigerant in the main circulation loop (i.e., the second refrigerant circulation loop) before throttling to increase the enthalpy difference. On the other hand, it appropriately preheats the low-pressure and low-temperature refrigerant in the auxiliary circuit (i.e., the first refrigerant circulation loop, which will be directly sucked into the middle of the compressor and compressed) after being reduced in pressure by the first electronic expansion valve to reach a suitable medium pressure, which is then provided to the compressor for secondary compression. It increases the compressor exhaust volume by compressing and jetting mixed cooling at medium and low pressures, and then compressing normally at high pressure, thereby improving heating capacity in low-temperature environments. It is fully suitable for vehicle-mounted heat pump heating in extremely cold regions such as Northeast my country, replacing the previous direct electric heating, reducing energy consumption, and improving battery life.

[0037] The oil-immersed integral battery pack is a type of battery pack that is filled with a special oil (such as transformer oil, etc.) into the gap between the battery pack and the outer shell of the battery, completely immersing the battery pack therein. The battery pack is insulated and heat-resistant, and oxygen-blocked, so that the battery is in the best working environment. The circulation inlets are reasonably and evenly distributed on the outer shell according to the size of the battery pack, and are connected to the battery-side heat exchanger through a multi-channel distributor. Refrigerant-directly cooled battery packs may have problems such as condensation forming condensed water due to the low refrigerant directly entering the battery pack, causing short circuits. Compared with refrigerant-direct cooling and other liquid-cooled battery packs, the present invention does not require the installation of heat exchange pipes in the battery pack, greatly reducing manufacturing costs. At the same time, the use of special insulating oil can not only effectively insulate the car battery in winter, but also can extinguish the arc in time after the battery is damaged by a collision, thereby improving driving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Schematic diagram of the structure of the low-temperature heat pump heating and cooling system of a new energy electric vehicle according to an embodiment. DETAILED DESCRIPTION

[0039] The present invention will be further described below with reference to the accompanying drawings and specific examples. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0040] In the following examples, the operating methods without specifying specific conditions are generally carried out under conventional conditions or conditions recommended by the manufacturer.

[0041] like Figure 1 As shown, a new energy electric vehicle low-temperature heat pump cooling and heating system includes a compressor 2;

[0042] The high-temperature and high-pressure refrigerant outlet of the compressor 2 is connected to the fourth port D of the four-way valve 1;

[0043] The second port B of the four-way valve 1 is connected to the refrigerant inlet of the compressor 2 through the gas-liquid separator 3. The third port C is connected to the refrigerant inlet in the middle of the compressor 2 through the liquid storage tank 14, the filter 18, the first electronic expansion valve 7, and the flash evaporator 6 in sequence. The first port A is connected to the liquid storage tank 14 through the superheat recovery device 20, the vehicle side heat exchanger 8, the second electronic expansion valve 17, the flash evaporator 6, and the filter 18 in sequence.

[0044] The battery-side heat exchanger 10 and the vehicle-interior heat exchanger 9 are connected in parallel and connected to the pipeline between the third port C and the liquid storage tank 14 .

[0045] A waste heat recovery device 4 connected to the electric drive 5 is provided on the pipeline between the flash evaporator 6 and the refrigerant inlet in the middle of the compressor 2. When the refrigerant in the pipeline flows through the waste heat recovery device 4, it can absorb the heat generated by the electric drive 5 and heat up, thereby promoting the heat dissipation of the electric drive 5 while reducing the load of the compressor 2.

[0046] The battery-side heat exchanger 10 is connected to the electrically controlled three-way valve 19 , the circulation pump 11 , the multi-channel distributor 12 and the oil-immersed integral battery pack to form a heat exchange medium circulation loop.

[0047] In the oil-immersed integral battery pack, the gap between the battery pack and the battery outer shell is filled with the heat exchange medium, and the battery pack is immersed in the heat exchange medium;

[0048] The battery outer shell is provided with multiple heat exchange medium circulation ports 13 connected in parallel and then connected to the multi-channel distributor 12. Each heat exchange medium circulation port 13 is provided with a temperature probe and a heat exchange medium flow control valve; the heat exchange medium flow control valve can adjust the heat exchange medium flow according to the temperature detected by the corresponding temperature probe to accurately control the battery temperature in the corresponding area.

[0049] The heat exchange medium circulation loop is provided with a safety valve 15 for timely pressure relief and an expansion tank 16 that can adapt to the volume change of the heat exchange medium due to thermal expansion and contraction.

[0050] The heat exchange medium is insulating transformer oil.

[0051] A heat exchange medium pipeline is provided in the overheat recovery device 20. One end of the heat exchange medium pipeline is connected to the remaining interface of the three-way valve 19, and the other end is connected to the pipeline between the battery-side heat exchanger 10 and the oil-immersed integral battery pack. The overheat recovery device 20 is connected to the three-way valve 19, the circulation pump 11, the multi-channel distributor 12 and the oil-immersed integral battery pack to form a battery overheat circulation loop.

[0052] Under normal circumstances, the three-way valve 19 connects the battery-side heat exchanger 10 and the circulation pump 11;

[0053] When the battery overheats due to long-term operation or intense driving in winter, the three-way valve 19 connects the overheat recovery device 20 and the circulation pump 11. When the overheated heat exchange medium flows through the heat recovery device 20 through the battery overheat circulation loop, it heats the refrigerant in the pipeline between the first interface A and the vehicle's outside heat exchanger 8 while cooling itself, thereby promoting battery heat dissipation and reducing the load on the compressor 2 to improve the energy efficiency of the system.

[0054] The control method of the low-temperature heat pump cooling and heating system of the new energy electric vehicle includes:

[0055] 1) Winter heating mode:

[0056] The first port A of the four-way valve 1 is connected to the second port B, and the third port C is connected to the fourth port D;

[0057] The compressor 2, the fourth port D, the third port C, the battery-side heat exchanger 10, the in-vehicle heat exchanger 9, the liquid storage tank 14, the filter 18, the first electronic expansion valve 7, the flash evaporator 6, the waste heat recovery device 4, and the refrigerant inlet in the middle of the compressor 2 form a first refrigerant circulation loop;

[0058] The compressor 2, the fourth port D, the third port C, the battery-side heat exchanger 10, the in-vehicle heat exchanger 9, the liquid storage tank 14, the filter 18, the flash evaporator 6, the second electronic expansion valve 17, the out-vehicle heat exchanger 8, the first port A, the second port B, and the refrigerant inlet of the compressor 2 form a second refrigerant circulation loop;

[0059] The refrigerant in the first refrigerant circulation loop and the refrigerant in the second refrigerant circulation loop perform heat exchange in the flash evaporator 6. The specific process is as follows:

[0060] In the first refrigerant circulation loop and the second refrigerant circulation loop, the high-temperature and high-pressure refrigerant coming out of the compressor 2 heats the battery and the interior environment while cooling itself when flowing through the battery side heat exchanger 10 and the vehicle interior side heat exchanger 9. The refrigerant in the pipeline is divided into two paths after passing through the liquid storage tank 14 and the filter 18. The refrigerant in the first refrigerant circulation loop that is further cooled after being reduced in pressure by the first electronic expansion valve 7 absorbs the heat of the refrigerant in the second refrigerant circulation loop when flowing through the flash evaporator 6, so that the refrigerant in the second refrigerant circulation loop is cooled and then reduced in pressure by the second electronic expansion valve 17 to obtain a lower temperature, so that it can more effectively absorb heat from the outside air when flowing through the vehicle exterior heat exchanger 8. The refrigerant in the first refrigerant circulation loop is heated by the flash evaporator 6 and then passes through the waste heat recovery device 4 connected to the electric drive 5 to absorb the heat generated by the electric drive 5 and further heat up, and finally enters the compressor 2 through the refrigerant inlet in the middle of the compressor 2, thereby promoting heat dissipation of the electric drive 5 while reducing the load of the compressor 2;

[0061] 2) Summer cooling mode:

[0062] The first electronic expansion valve 7 and the flash evaporator 6 are always closed;

[0063] The first port A of the four-way valve 1 is connected to the fourth port D, and the second port B is connected to the third port C;

[0064] The high-temperature and high-pressure refrigerant coming out of the compressor 2 dissipates heat and cools down to the outside air when flowing through the vehicle-side heat exchanger 8, and then is further cooled down after being reduced in pressure by the second electronic expansion valve 17 to form a low-temperature and low-pressure refrigerant. Then, when flowing through the battery-side heat exchanger 10 and the vehicle-side heat exchanger 9, heat exchange is performed to provide cooling for the battery and the vehicle interior environment while heating itself. Finally, it enters the third interface C, the second interface B, and the refrigerant inlet in sequence and returns to the compressor 2 for the next cycle.

[0065] In addition, it should be understood that after reading the above description of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

Claims

1. A low-temperature heat pump cooling and heating system for new energy electric vehicles, characterized in that: including a compressor (2); The high-temperature and high-pressure refrigerant outlet of the compressor (2) is connected to the fourth interface (D) of the four-way valve (1); The second interface (B) of the four-way valve (1) is connected to the refrigerant inlet of the compressor (2), the third interface (C) is connected to the refrigerant inlet in the middle of the compressor (2) through the liquid storage tank (14), the first electronic expansion valve (7), and the flash evaporator (6) in sequence, and the first interface (A) is connected to the liquid storage tank (14) through the vehicle outside heat exchanger (8), the second electronic expansion valve (17), and the flash evaporator (6) in sequence; Winter heating mode: the first interface (A) of the four-way valve (1) is connected to the second interface (B), and the third interface (C) is connected to the fourth interface (D); the compressor (2), the fourth interface (D), the third interface (C), the battery side heat exchanger (10), the vehicle interior side heat exchanger (9), the liquid storage tank (14), the first electronic expansion valve (7), the flash evaporator (6) and the refrigerant inlet in the middle of the compressor (2) form a first refrigerant circulation loop; the compressor (2), the fourth interface (D), the third interface (C), the battery side heat exchanger (10), the vehicle interior side heat exchanger (9), the liquid storage tank (14), the flash evaporator (6), the second electronic expansion valve (17), the vehicle exterior side heat exchanger (8), the first interface (A), the second interface (B) and the refrigerant inlet of the compressor (2) form a second refrigerant circulation loop; the refrigerant in the first refrigerant circulation loop and the refrigerant in the second refrigerant circulation loop perform heat exchange in the flash evaporator (6), The specific process is as follows: in the first refrigerant circulation loop and the second refrigerant circulation loop, the high-temperature and high-pressure refrigerant coming out of the compressor (2) heats the battery and the interior environment while cooling itself when flowing through the battery side heat exchanger (10) and the vehicle interior side heat exchanger (9). The refrigerant in the pipeline is divided into two paths after passing through the liquid storage tank (14). The refrigerant in the first refrigerant circulation loop that is further cooled after being reduced in pressure by the first electronic expansion valve (7) absorbs the heat of the refrigerant in the second refrigerant circulation loop when flowing through the flash evaporator (6), so that the refrigerant in the second refrigerant circulation loop is cooled and then reduced in pressure by the second electronic expansion valve (17) to obtain a lower temperature, thereby being able to more effectively absorb heat from the outside air when flowing through the vehicle exterior side heat exchanger (8). The refrigerant in the first refrigerant circulation loop enters the compressor (2) through the refrigerant inlet in the middle of the compressor (2) after being heated by the flash evaporator (6), which can reduce the load of the compressor (2); The battery side heat exchanger (10) and the vehicle interior side heat exchanger (9) are connected in parallel and then connected to the pipeline between the third interface (C) and the liquid storage tank (14); The battery side heat exchanger (10) is connected to the circulation pump (11), the multi-channel distributor (12) and the oil-immersed integral battery pack to form a heat exchange medium circulation loop; An overheat recovery device (20) is provided on the pipeline between the first interface (A) and the vehicle-side heat exchanger (8); a heat exchange medium pipeline is provided in the overheat recovery device (20); one end of the heat exchange medium pipeline is connected to the pipeline between the battery-side heat exchanger (10) and the circulation pump (11) through a three-way valve (19), and the other end is connected to the pipeline between the battery-side heat exchanger (10) and the oil-immersed integral battery pack; the overheat recovery device (20) is connected to the three-way valve (19), the circulation pump (11), the multi-channel distributor (12) and the oil-immersed integral battery pack to form a battery overheat circulation loop; Under normal circumstances, the three-way valve (19) connects the battery side heat exchanger (10) and the circulation pump (11); When the battery is overheated due to long-term operation or intense driving in winter, the three-way valve (19) connects the overheat recovery device (20) and the circulation pump (11). When the overheated heat exchange medium flows through the heat recovery device (20) through the battery overheat circulation loop, it heats the refrigerant in the pipeline between the first interface (A) and the vehicle-side heat exchanger (8) while cooling itself, thereby promoting heat dissipation of the battery and reducing the load of the compressor (2) to improve the energy efficiency of the system.

2. The low-temperature heat pump cooling and heating system for new energy electric vehicles according to claim 1 is characterized in that: A filter (18) is provided on the pipeline between the liquid storage tank (14), the first electronic expansion valve (7) and the flash evaporator (6).

3. The low-temperature heat pump cooling and heating system for new energy electric vehicles according to claim 1 is characterized in that: A gas-liquid separator (3) is provided on the pipeline between the second interface (B) and the refrigerant inlet of the compressor (2).

4. The low-temperature heat pump cooling and heating system for new energy electric vehicles according to claim 1, characterized in that: A waste heat recovery device (4) connected to the electric drive (5) is provided on the pipeline between the flash evaporator (6) and the refrigerant inlet in the middle of the compressor (2). When the refrigerant in the pipeline flows through the waste heat recovery device (4), it can absorb the heat generated by the electric drive (5) and increase its temperature, thereby promoting the heat dissipation of the electric drive (5) and reducing the load of the compressor (2).

5. The low-temperature heat pump cooling and heating system for new energy electric vehicles according to any one of claims 1 to 4, characterized in that: In the oil-immersed integral battery pack, the gap between the battery pack and the battery outer shell is filled with the heat exchange medium, and the battery pack is immersed in the heat exchange medium; The battery outer shell is provided with a plurality of heat exchange medium circulation ports (13) which are connected in parallel and then connected to a multi-channel distributor (12), and each heat exchange medium circulation port (13) is provided with a temperature probe and a heat exchange medium flow regulating valve; the heat exchange medium flow regulating valve can regulate the heat exchange medium flow according to the temperature detected by the corresponding temperature probe to accurately control the battery temperature in the corresponding area.

6. The low-temperature heat pump cooling and heating system for new energy electric vehicles according to claim 5, characterized in that: The heat exchange medium circulation loop is provided with a safety valve (15) capable of timely pressure relief.

7. The low-temperature heat pump cooling and heating system for new energy electric vehicles according to claim 5, characterized in that: The heat exchange medium circulation loop is provided with an expansion tank (16) which can adapt to the volume change of the heat exchange medium due to thermal expansion and contraction.

8. The low-temperature heat pump cooling and heating system for new energy electric vehicles according to claim 5, characterized in that: The heat exchange medium is insulating transformer oil.

9. The control method of the low-temperature heat pump cooling and heating system of a new energy electric vehicle according to any one of claims 1 to 8, characterized in that: include: 1) Winter heating mode: The first port (A) of the four-way valve (1) is in communication with the second port (B), and the third port (C) is in communication with the fourth port (D); The compressor (2), the fourth interface (D), the third interface (C), the battery side heat exchanger (10), the vehicle interior side heat exchanger (9), the liquid storage tank (14), the first electronic expansion valve (7), the flash evaporator (6) and the refrigerant inlet in the middle of the compressor (2) form a first refrigerant circulation loop; The compressor (2), the fourth interface (D), the third interface (C), the battery side heat exchanger (10), the vehicle interior side heat exchanger (9), the liquid storage tank (14), the flash evaporator (6), the second electronic expansion valve (17), the vehicle exterior side heat exchanger (8), the first interface (A), the second interface (B) and the refrigerant inlet of the compressor (2) form a second refrigerant circulation loop; The refrigerant in the first refrigerant circulation loop and the refrigerant in the second refrigerant circulation loop perform heat exchange in the flash evaporator (6), and the specific process is as follows: In the first refrigerant circulation loop and the second refrigerant circulation loop, the high-temperature and high-pressure refrigerant coming out of the compressor (2) provides heat to the battery and the interior environment while cooling itself when flowing through the battery side heat exchanger (10) and the vehicle interior side heat exchanger (9). The refrigerant in the pipeline is divided into two paths after passing through the liquid storage tank (14). The refrigerant in the first refrigerant circulation loop that is further cooled after being reduced in pressure by the first electronic expansion valve (7) absorbs the heat of the refrigerant in the second refrigerant circulation loop when flowing through the flash evaporator (6), so that the refrigerant in the second refrigerant circulation loop is cooled and then reduced in pressure by the second electronic expansion valve (17) to obtain a lower temperature, thereby being able to more effectively absorb heat from the outside air when flowing through the vehicle exterior side heat exchanger (8). The refrigerant in the first refrigerant circulation loop enters the compressor (2) through the refrigerant inlet in the middle of the compressor (2) after being heated by the flash evaporator (6), which can reduce the load of the compressor (2); 2) Summer cooling mode: The first electronic expansion valve (7) and the flash evaporator (6) are always closed; The first port (A) of the four-way valve (1) is in communication with the fourth port (D), and the second port (B) is in communication with the third port (C); The high-temperature and high-pressure refrigerant coming out of the compressor (2) dissipates heat and cools down to the outside air when flowing through the vehicle-side heat exchanger (8), and then further cools down to form a low-temperature and low-pressure refrigerant after being reduced in pressure by the second electronic expansion valve (17). Then, when flowing through the battery-side heat exchanger (10) and the vehicle-side heat exchanger (9), heat exchange is performed to cool the battery and the vehicle interior environment while the refrigerant itself is heated. Finally, it passes through the third interface (C), the second interface (B), and the refrigerant inlet in sequence and returns to the compressor (2) for the next cycle.

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