A heat pump system and a control method thereof

Abstract

The application discloses a heat pump system and a control method thereof, and the system comprises: an air path regulation unit arranged in a passenger cabin, comprising a first indoor heat exchanger, a second indoor heat exchanger and an outdoor heat exchanger, and a refrigerant circulating and flowing in the air path regulation unit under the driving of a compressor; and a water path regulation unit arranged at a battery side, comprising a water pump and a battery water path heat exchanger, and circulating water is driven by the water pump to flow through the battery water path heat exchanger and the battery, and heat or cold is transferred from the battery heat exchanger to the battery; wherein the output end of the compressor is connected with the air path regulation unit and the water path regulation unit through a plurality of control switches, so that the regulation modes of the passenger cabin and the battery are realized. The system and the method can heat or cool the passenger cabin, and can also heat or cool the battery, so that the energy-saving effect of the heat pump system is fully utilized, the energy consumption of the whole vehicle under a low-temperature working condition is reduced, and the cruising range of the electric vehicle is increased.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of automobile air conditioning, and in particular to a heat pump system capable of simultaneously or separately heating or cooling the passenger cabin and the battery and a control method thereof. BACKGROUND

[0002] With the strengthening of environmental protection regulations and the increasing requirement of carbon emission, new energy vehicles have been rapidly developed and widely promoted. Since new energy vehicles do not have an engine to provide additional heat, the heat energy used by the air conditioner for heating in winter comes entirely from the battery power, which directly shortens the vehicle's range and exacerbates the range anxiety of electric vehicles. Therefore, designing a more energy-efficient heating device for electric vehicles is a key link to improve the range and driving experience of electric vehicles. During the operation of an electric vehicle, the working temperature of the battery needs to be maintained within an appropriate range, otherwise the range and life of the battery will be affected. Therefore, the air conditioning system of the electric vehicle must meet the demand of heating or cooling the battery while ensuring the comfort of the passenger cabin.

[0003] The current mainstream solutions for heating electric vehicles are PTC heating and heat pump air conditioning. PTC (Positive Temperature Coefficient) is a ceramic semiconductor element that generates heat after being powered on. PTC converts electrical energy into heat energy, and the energy efficiency ratio (heating capacity to consumed electrical energy) is less than 1, which consumes a lot of energy and significantly reduces the winter range of electric vehicles. Heat pump air conditioning technology is based on the Carnot cycle principle, which uses a compressor, a heat exchanger, and an expansion valve to transfer heat energy from the environment to the passenger cabin. The energy efficiency ratio is higher than 1, which can reach 2 or more. Therefore, under the same heating capacity, the energy consumption of a heat pump air conditioning system is about half or less than that of a PTC system, which is more energy-efficient. However, most electric vehicles on the market that use heat pumps still use traditional refrigerants R134a or R1234yf as refrigerants. Due to the rapid decline in energy density of these two refrigerants below 0℃, the working range of the heat pump air conditioning system is limited, and the heating capacity is insufficient in low-temperature environments (below -5℃), which still requires PTC to supplement the heat.

[0004] Carbon dioxide, as a natural working medium, has good low-temperature thermodynamic properties, and also has environmental protection and price advantages, so it has great potential for application in automobile heat pump air conditioning. Currently, Volkswagen has mass-produced electric vehicles equipped with carbon dioxide heat pump systems, but these models only apply the heat pump system to passenger cabin comfort and battery cooling. The battery still needs to rely on PTC for heating in low-temperature conditions. In view of the high energy consumption of PTC and the poor performance of traditional refrigerant heat pumps in low-temperature conditions, in order to reduce system energy consumption and meet the demand of simultaneously heating or cooling the passenger cabin and the battery for the electric vehicle heat pump air conditioning system, SUMMARY

[0005] The present application provides a novel heat pump system and its control method, which has multiple working modes such as passenger cabin heating, dehumidification, refrigeration and battery heating, cooling, etc., and can simultaneously or separately heat or cool the passenger cabin and the battery. The present application describes how the heat pump system switches between different modes and how to adjust the air conditioner to distribute the heating and cooling capacity to the passenger cabin and the battery, so as to not only meet the comfort requirements of the passenger cabin, but also meet the requirements of the working environment of the battery.

[0006] It should be understood that the general description above and the following detailed description of the present disclosure are exemplary and illustrative, and are intended to provide further explanation of the present disclosure.

[0007] The present application provides a heat pump system, comprising a compressor, characterized in that the system comprises:

[0008] A gas path control unit is provided in the passenger cabin, which comprises a first and a second indoor heat exchanger and an outdoor heat exchanger. The refrigerant is circulated and flows in the gas path control unit under the driving of the compressor;

[0009] A water path control unit is provided on the battery side, which comprises a water pump and a battery water path heat exchanger. The circulating water is driven by the water pump to flow through the battery water path heat exchanger and the battery, and the heat or cold is transferred from the battery heat exchanger to the battery;

[0010] The output end of the compressor is connected to the gas path control unit and the water path control unit through a plurality of control switches, realizing the control mode of the passenger cabin and the battery.

[0011] Preferably, the present application further provides a heat pump system, characterized in that,

[0012] The plurality of control switches comprises first to fourth expansion valves and first to sixth stop valves;

[0013] The first end of the first indoor heat exchanger is connected to the battery water path heat exchanger through the fourth expansion valve, the second end is connected to the second end of the outdoor heat exchanger through the third stop valve, and the first end is connected to the second end of the second indoor heat exchanger through the first expansion valve;

[0014] The first end of the second indoor heat exchanger is connected to the first end of the outdoor heat exchanger through the second expansion valve, and the first end is also connected to the first end of the battery water path heat exchanger through the third expansion valve. The second end of the second indoor heat exchanger is connected to the second end of the battery water path heat exchanger through the fourth stop valve and the sixth stop valve;

[0015] The second end of the outdoor heat exchanger is connected to the second end of the compressor through the second stop valve, and the second end of the outdoor heat exchanger is connected between the sixth stop valve and the fourth stop valve through the fifth stop valve;

[0016] The first end of the compressor is connected between the sixth stop valve and the fourth stop valve, and the second end is connected with the first end of the first internal heat exchanger through the first stop valve.

[0017] Preferably, the present application further provides a heat pump system, characterized in that,

[0018] In the gas path control unit, the flow direction of the refrigerant is changed by opening and closing of the first to sixth stop valves, and the refrigerant releases heat on the high-pressure side to the gas path control unit or the water path control unit and absorbs heat on the low-pressure side from the gas path control unit or the water path control unit by using the throttling pressure difference of the first to fourth expansion valves, so as to realize heating or refrigeration.

[0019] Preferably, the present application further provides a heat pump system, characterized in that, the control mode further comprises:

[0020] The passenger cabin control mode and the battery control mode, wherein the passenger cabin control mode comprises any one of passenger cabin refrigeration, heating and dehumidification, the battery control mode comprises any one of battery refrigeration and heating, and a combination of one of the passenger cabin control mode and the battery control mode.

[0021] The present application also provides a control method for the above-mentioned heat pump system, characterized in that,

[0022] Step one, according to the temperature or humidity demand, obtain the air volume of the air blower and the flow of the water pump;

[0023] Step two, according to the target temperature and the measured temperature, calculate the passenger cabin control demand and the battery control demand, the target temperature includes the passenger cabin target dew point temperature and the target air outlet temperature, and the measured temperature includes the inlet air temperature and the battery temperature;

[0024] Step three, according to the passenger cabin control demand and the battery control demand, adjust the on-off of each stop valve and expansion valve, and control the system operation mode;

[0025] Step four, compare the passenger cabin control demand and the battery control demand, when the passenger cabin and the battery control requirements are heat absorption at the same time or heat release at the same time, the second expansion valve is controlled according to the compressor discharge temperature and pressure, and the first and third expansion valves control the energy output distribution.

[0026] When the passenger cabin and the battery control requirements are heat release and heat absorption respectively, the second expansion valve controls the energy output distribution, and the first and third expansion valves are controlled according to the compressor discharge temperature and pressure.

[0027] Preferably, the application further provides a control method, characterized in that in the step two, the passenger cabin regulation requirement comprises a passenger cabin target energy requirement Q cabin For:

[0028] Q cabin =a*(T target -T in )*V (1)

[0029] Wherein, a is a fixed coefficient calibrated, T target is a target air outlet temperature or a target dew point temperature of the passenger cabin, T in is an inlet air temperature, and V is a blower air volume;

[0030] The battery regulation requirement comprises a battery target energy requirement Q bat For:

[0031] Q bat =b*T bat +c (2)

[0032] Wherein, b and c are fixed coefficients, which are calculated by a battery temperature T bat .

[0033] The target dew point temperature of the passenger cabin is obtained by looking up a table of outside temperature and air humidity.

[0034] Preferably, the application further provides a control method, characterized in that the system operation mode of the step three comprises a passenger cabin heating mode, a passenger cabin dehumidification mode, a passenger cabin refrigeration mode, a battery heating mode, a battery cooling mode, a passenger cabin-battery simultaneous heating mode, a passenger cabin heating-battery cooling mode, a passenger cabin dehumidification-battery heating mode, a passenger cabin dehumidification-battery cooling mode, a passenger cabin refrigeration-battery heating mode, a passenger cabin refrigeration-battery cooling mode, and a mode of heating the passenger cabin by using motor waste heat.

[0035] Wherein, in the passenger cabin heating mode, the first and fifth stop valves are opened, the second, third, fourth and sixth stop valves are closed, the first and second expansion valves are throttled, and the third and fourth expansion valves are closed.

[0036] In the passenger cabin dehumidification mode, the first, third and fourth stop valves are opened, the second, fifth and sixth stop valves are closed, the second expansion valve is throttled, and the first, third and fourth expansion valves are closed.

[0037] In the passenger cabin refrigeration mode, the second and fourth stop valves are opened, the first, third, fifth and sixth stop valves are closed, the second expansion valve is throttled, and the first, third and fourth expansion valves are closed.

[0038] In the battery heating mode, the first and fifth stop valves are open, the second, third, fourth and sixth stop valves are closed, the second and fourth expansion valves are throttled, the third expansion valve is open, and the first expansion valve is closed;

[0039] In the battery cooling mode, the second and sixth stop valves are open, the first, third, fourth and fifth stop valves are closed, the second expansion valve is throttled, the third expansion valve is open, and the first and fourth expansion valves are closed;

[0040] In the passenger cabin heating-battery heating mode, the first and fifth stop valves are open, the second, third, fourth and sixth stop valves are closed, and the first, second, third and fourth expansion valves are throttled;

[0041] In the passenger cabin heating-battery cooling mode, when the required heat of the passenger cabin is close to the required cooling of the battery, the first and sixth stop valves are open, the second, third, fourth and fifth stop valves are closed, the first and third expansion valves are throttled, and the second and fourth expansion valves are closed; when the required heat of the passenger cabin is greater than the required cooling of the battery, the first, fifth and sixth stop valves are open, the second, third and fourth stop valves are closed, the first, second and third expansion valves are throttled, and the fourth expansion valve is closed; when the required heat of the passenger cabin is less than the required cooling of the battery, the first, second and sixth stop valves are open, the third, fourth and fifth stop valves are closed, the first, second and third expansion valves are throttled, and the fourth expansion valve is closed;

[0042] In the passenger cabin dehumidification-battery heating mode, the first, third and fourth stop valves are open, the second, fifth and sixth stop valves are closed, the second, third and fourth expansion valves are throttled, and the first expansion valve is closed;

[0043] In the passenger cabin dehumidification-battery cooling mode, the first, third, fourth and sixth stop valves are open, the second and fifth stop valves are closed, the second and third expansion valves are throttled, and the first and fourth expansion valves are closed;

[0044] In the passenger cabin refrigeration-battery heating mode, when the required cooling of the passenger cabin is close to the required heat of the battery, the first and fourth stop valves are open, the second, third, fifth and sixth stop valves are closed, the third and fourth expansion valves are throttled, and the first and second expansion valves are closed; when the required cooling of the passenger cabin is less than the required heat of the battery, the first, fourth and fifth stop valves are open, the second, third and sixth stop valves are closed, the second, third and fourth expansion valves are throttled, and the first expansion valve is closed; when the required cooling of the passenger cabin is greater than the required heat of the battery, the first, second and fourth stop valves are open, the third, fifth and sixth stop valves are closed, the second, third and fourth expansion valves are throttled, and the first expansion valve is closed;

[0045] In the passenger cabin refrigeration-battery cooling mode, the second, fourth and sixth stop valves are open, the first, third and fifth stop valves are closed, the second and third expansion valves are throttled, and the first expansion valve is closed;

[0046] In the mode of heating the passenger cabin by using the motor waste heat, the first, fifth and sixth stop valves are opened, the second, third and fourth stop valves are closed, the first, second and third expansion valves are throttled, the fourth expansion valve is closed, the battery water circuit heat exchanger is connected with the motor, and the system absorbs heat from the motor.

[0047] The system and method of the present application can heat, dehumidify or cool the passenger cabin, and heat or cool the battery, fully utilize the energy-saving effect of the heat pump system, thereby reducing the energy consumption of the whole vehicle under low temperature working condition, and increasing the cruising range of the electric vehicle. BRIEF DESCRIPTION OF DRAWINGS

[0048] Embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. Reference will now be made in detail to the preferred embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used in all drawings to refer to the same or like parts. Also, although the terms used in the present disclosure are selected from generally known and used terms, some of the terms mentioned in the description of the present disclosure can be selected by the applicant in his or her judgment from among the terms in accordance with the technical concept of the present disclosure, and the detailed meanings thereof are described in relevant parts of the description herein. Furthermore, the present disclosure is to be understood not only by the actual terms used but also by the meanings of each term based on the meaning mentioned herein and by the meaning throughout the description herein and / or the accompanying drawings. Accordingly, the present disclosure is not limited to only the terms used and should be understood by the meaning and concepts of each term.

[0049] Hereinafter, the above and other objects, features and advantages of the present application will become apparent from the detailed description of the present application, with reference to the accompanying drawings.

[0050] Figure 1 is a structure composition block diagram of the heat pump system of the present application;

[0051] Figure 2 is a system arrangement schematic diagram of the present application;

[0052] Figure 3 is a structure schematic diagram of the present application in the passenger cabin-battery simultaneous heating mode;

[0053] Figure 4 is a control flowchart of the present application in the passenger cabin-battery simultaneous heating mode;

[0054] Figure 5 is a structure schematic diagram of the present application in the passenger cabin heating mode;

[0055] Figure 6 is a structure schematic diagram of the present application in the passenger cabin dehumidification mode;

[0056] Figure 7 is a structure schematic diagram of the present application in the passenger cabin cooling mode;

[0057] Figure 8 is a structure schematic diagram of the present application in the battery heating mode;

[0058] Figure 9 is a structural schematic diagram of the system in the battery cooling mode of the application;

[0059] Figures 10(1) to 10(3) are three different structural schematic diagrams of the system in the passenger cabin heating-battery cooling mode of the application, respectively;

[0060] Figure 11 is a structural schematic diagram of the system in the passenger cabin dehumidification-battery heating mode of the application;

[0061] Figure 12 is a structural schematic diagram of the system in the passenger cabin dehumidification-battery cooling mode of the application;

[0062] Figures 13(1) to 13(3) are three different structural schematic diagrams of the system in the passenger cabin refrigeration-battery heating mode of the application, respectively;

[0063] Figure 14 is a structural schematic diagram of the system in the passenger cabin-battery simultaneous refrigeration mode of the application;

[0064] Figure 15 is a structural schematic diagram of the application in the motor waste heat passenger cabin heating mode.

[0065] Reference signs

[0066] 11 - compressor

[0067] 12 - outdoor heat exchanger

[0068] 13 - first internal heat exchanger

[0069] 14 - second internal heat exchanger

[0070] 15 - battery water circuit heat exchanger

[0071] 16 - first stop valve

[0072] 17 - second stop valve

[0073] 18 - third stop valve

[0074] 19 - fourth stop valve

[0075] 20 - fifth stop valve

[0076] 21 - sixth stop valve

[0077] 22 - first expansion valve

[0078] 23 - second expansion valve

[0079] 24 - third expansion valve

[0080] 25 - fourth expansion valve

[0081] 30 - battery

[0082] 31 - battery cooling plate

[0083] 33 - temperature damper

[0084] 34 - blower

[0085] 35 - water pump

[0086] 100 - air circuit control unit

[0087] 200 - water circuit control unit DETAILED DESCRIPTION

[0088] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some examples or embodiments of the present application, and for those skilled in the art, the present application can be applied to other similar scenarios without creative labor on the basis of these drawings. Unless it is clear from the language context or otherwise indicated, the same reference numbers in the drawings represent the same structure or operation.

[0089] As shown in the present application and claims, unless the context clearly indicates otherwise, the words "one", "an", "a", and / or "the" do not mean to specify a single number, but can also include a plurality. Generally speaking, the terms "comprising" and "including" only indicate including the steps and elements explicitly identified, and these steps and elements do not constitute an exclusive list, and the method or device can also include other steps or elements.

[0090] Unless otherwise specifically indicated, the relative arrangement of the components and steps, numerical expressions, and values set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that the sizes of the various parts shown in the drawings are not drawn in accordance with the actual proportional relationship. The technology, methods and devices known to those skilled in the relevant art can not be discussed in detail, but in appropriate cases, the technology, methods and devices should be considered as part of the authorized specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, and not as a limitation. Therefore, other examples of exemplary embodiments can have different values. It should be noted that similar reference numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0091] In the description of the present application, it needs to be understood that the orientation words such as "front, back, up, down, left, right", "transverse, vertical, perpendicular, horizontal" and "top, bottom" and the like indicated orientation or position relationship are generally based on the orientation or position relationship shown in the drawings, only for the convenience of describing the present application and simplifying the description, without making the opposite statement, these orientation words do not indicate and imply that the indicated device or element must have a particular orientation or be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation on the scope of protection of the present application; the orientation words "inner, outer" refer to the inner and outer of the contour of each component itself.

[0092] For the convenience of description, spatial relative terms such as "over", "above", "upper surface", "upper" and the like can be used herein to describe the spatial position relationship of one device or feature with other devices or features as shown in the drawings. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientation of the device described in the drawings. For example, if the device in the drawing is inverted, the device described as "above" or "over" other devices or structures will be positioned "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below" orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein are interpreted accordingly.

[0093] In addition, it needs to be explained that the use of "first", "second" and the like to define parts is only for the convenience of distinguishing the corresponding parts, and the above words have no special meaning unless otherwise stated, therefore it cannot be understood as a limitation on the scope of protection of the present application. In addition, although the terms used in the present application are selected from commonly known and used terms, some terms mentioned in the specification of the present application can be selected by the applicant according to his or her judgment, and the detailed meanings of the terms are described in the relevant part of the description. In addition, the present application is required to be understood not only by the actual terms used, but also by the meaning implied by each term.

[0094] The structure of the heat pump system of the present application is as shown in Figure 1

[0095] The heat pump system includes compressor 11, outdoor heat exchanger 12, first indoor heat exchanger 13, second indoor heat exchanger 14, battery water circuit heat exchanger 15, first to sixth stop valves 16-21 and first to fourth electronic expansion valves 22-25 and other components. The above components belong to gas circuit control unit 100 and water circuit control unit 200 respectively.

[0096] Figure 1 ​The air circuit control unit 100 is shown by the middle solid line.

[0097] The air circuit control unit 100 is arranged at the side of the passenger cabin, and includes two internal heat exchangers and one external heat exchanger. The internal heat exchangers are the first and second internal heat exchangers 13 and 14. The first end of the first internal heat exchanger 13 is connected to the battery water circuit heat exchanger 15 in the water circuit control unit 200 through the expansion valve 25, the second end of the first internal heat exchanger 13 is connected to the second end of the external heat exchanger 12 through the stop valve 18, and the second end of the first internal heat exchanger 13 is connected to the second end of the second internal heat exchanger 14 through the expansion valve 22.

[0098] The first end of the second internal heat exchanger 14 is connected to the first end of the external heat exchanger 12 through the expansion valve 23, and the first end of the second internal heat exchanger 14 is also connected to the first end of the battery water circuit heat exchanger 15 through the expansion valve 24. The second end of the second internal heat exchanger 14 is connected to the second end of the battery water circuit heat exchanger 15 through the stop valve 19 and the stop valve 21.

[0099] The second end of the external heat exchanger 12 is connected to the second end of the compressor 11 through the stop valve 17, and the second end of the external heat exchanger 12 is also connected between the stop valve 21 and the stop valve 19 through the stop valve 20.

[0100] The first end of the compressor 11 is connected between the stop valve 6 and the stop valve 4, and the second end of the compressor 11 is connected to the first end of the first internal heat exchanger 13 through the stop valve 16.

[0101] In the air circuit control unit 100, the refrigerant circulates in the system under the drive of the compressor 11, the flow direction is changed by the opening and closing of the stop valves 16-21, and the pressure difference is established by the throttling of the expansion valves 22-25. The air circuit / water circuit is heated on the high-pressure side and cooled on the low-pressure side, so as to achieve the effects of heating or cooling.

[0102] Figure 1 The water circuit control unit 200 is shown by the middle dashed line, and is arranged at the side of the battery. The water circuit control unit 200 includes the battery water circuit heat exchanger 15 and the water pump 35. Under the drive of the water pump 35, the circulating water flows through the battery water circuit heat exchanger 15 and the battery 30, so as to transfer the heat or cold from the heat exchanger to the battery 30, thereby achieving the effects of heating or cooling the battery.

[0103] In addition, the heat of the motor is transferred to the heat exchanger through the water circuit by switching the valves in the water circuit, so as to heat the passenger cabin by using the waste heat of the motor. By switching the valves and adjusting the temperature damper, the heating or cooling distribution of the heat pump air conditioner to the passenger cabin and the battery can be switched between different working modes of the heat pump.

[0104] The system arrangement of the present application is shown in Figure 2 .

[0105] Besides the system related components, the blower 34 and the temperature damper 33 are also shown. Among them, the compressor 11 is used to drive the carbon dioxide to circulate in the system. The outdoor heat exchanger 12 is used to exchange heat with the outside air. The first and second indoor heat exchangers 13 and 14 are used to exchange heat with the air in the air conditioning box, so as to change the air conditioning outlet temperature in the vehicle. The battery water circuit heat exchanger 15 is used to exchange heat with the battery water circuit, so as to provide heat or cold to the battery 30 through the battery cooling plate 31. The functions of the stop valves 16-21 are to change the flow direction of the carbon dioxide in the pipeline, so as to change the operation mode. The functions of the expansion valves 22-25 are to establish high and low pressure difference and temperature difference through throttling, to realize heat exchange, and to control the refrigerant flow in a certain circuit, to adjust the heat distribution.

[0106] By adjusting the on-off of each stop valve and expansion valve, the system can realize twelve operation modes, which can be referred to Figure 3 and Figures 5 to 15 , and the specific control scheme is described as follows:

[0107] Figure 3 Corresponding to the passenger cabin heating-battery heating mode: the stop valves 16 and 20 are open, the stop valves 17, 18, 19 and 21 are closed, the expansion valves 22, 23, 24 and 25 are throttled, and the temperature damper is fully open. The system simultaneously realizes passenger cabin heating and battery heating.

[0108] Figure 5 Corresponding to the passenger cabin heating mode: the stop valves 16 and 20 are open, the stop valves 17, 18, 19 and 21 are closed, the expansion valves 22 and 23 are throttled, the expansion valves 24 and 25 are closed, and the temperature damper is fully open. The system is for passenger cabin heating.

[0109] Figure 6 Corresponding to the passenger cabin dehumidification mode: the stop valves 16, 18 and 19 are open, the stop valves 17, 20 and 21 are closed, the expansion valve 23 is throttled, the expansion valves 22, 24 and 25 are closed, and the temperature damper is controllable. The system is for passenger cabin dehumidification.

[0110] Figure 7 Corresponding to the passenger cabin cooling mode: the stop valves 17 and 19 are open, the stop valves 16, 18, 20 and 21 are closed, the expansion valve 23 is throttled, the expansion valves 22, 24 and 25 are closed, and the temperature damper is fully closed. The system is for passenger cabin cooling.

[0111] Figure 8 Corresponding to the battery heating mode: the stop valves 16 and 20 are open, the stop valves 17, 18, 19 and 21 are closed, the expansion valves 23 and 25 are throttled, the expansion valve 24 is open, and the expansion valve 22 is closed. The system is for battery heating.

[0112] Figure 9Corresponding to the battery cooling mode: the stop valves 17, 21 are open, the stop valves 16, 18, 19, 20 are closed, the expansion valve 23 throttles, the expansion valve 24 is open, and the expansion valves 22, 25 are closed. The system is battery cooling.

[0113] Figures 10(1) to 10(3) Corresponding to the three cases of passenger cabin heating-battery cooling mode respectively:

[0114] When the required heat of the passenger cabin is similar to the required cold of the battery, the stop valves 16, 21 are open, the stop valves 17, 18, 19, 20 are closed, the expansion valves 22, 24 throttle, and the expansion valves 23, 25 are closed. The system simultaneously realizes passenger cabin heating and battery cooling;

[0115] When the required heat of the passenger cabin is greater than the required cold of the battery, the stop valves 16, 20, 21 are open, the stop valves 17, 18, 19 are closed, the expansion valves 22, 23, 24 throttle, and the expansion valve 25 is closed. The system simultaneously realizes passenger cabin heating and battery cooling;

[0116] When the required heat of the passenger cabin is less than the required cold of the battery, the stop valves 16, 17, 21 are open, the stop valves 18, 19, 20 are closed, the expansion valves 22, 23, 24 throttle, and the expansion valve 25 is closed. The system simultaneously realizes passenger cabin heating and battery cooling.

[0117] Figure 11 Corresponding to the passenger cabin dehumidification-battery heating mode: the stop valves 16, 18, 19 are open, the stop valves 17, 20, 21 are closed, the expansion valves 23, 24, 25 throttle, the expansion valve 22 is closed, and the temperature damper is controllable. The system simultaneously realizes passenger cabin dehumidification and battery heating.

[0118] Figure 12 Corresponding to the passenger cabin dehumidification-battery cooling mode: the stop valves 16, 18, 19, 21 are open, the stop valves 17, 20 are closed, the expansion valves 23, 24 throttle, the expansion valves 22, 25 are closed, and the temperature damper is controllable. The system simultaneously realizes passenger cabin dehumidification and battery cooling.

[0119] Figures 13(1) to 13(3) Corresponding to the three cases of passenger cabin cooling-battery heating mode respectively:

[0120] When the required cold of the passenger cabin is similar to the required heat of the battery, the stop valves 16, 19 are open, the stop valves 17, 18, 19, 21 are closed, the expansion valves 24, 25 throttle, the expansion valves 22, 23 are closed, and the temperature damper is fully open. The system simultaneously realizes passenger cabin cooling and battery heating;

[0121] When the required cold of the passenger cabin is less than the required heat of the battery, the stop valves 16, 19, 20 are open, the stop valves 17, 18, 21 are closed, the expansion valves 23, 24, 25 throttle, the expansion valve 22 is closed, and the temperature damper is fully open. The system simultaneously realizes passenger cabin cooling and battery heating;

[0122] When the required cooling capacity of the passenger cabin is greater than the required heating capacity of the battery, the shut-off valves 16, 17 and 19 are opened, the shut-off valves 18, 20 and 21 are closed, the expansion valves 23, 24 and 25 are throttled, the expansion valve 22 is closed, and the temperature damper is fully opened. The system simultaneously realizes passenger cabin refrigeration and battery heating;

[0123] Figure 14 Corresponding to the passenger cabin refrigeration-battery cooling mode: the shut-off valves 17, 19 and 21 are opened, the shut-off valves 16, 18 and 20 are closed, the expansion valves 23 and 24 are throttled, the expansion valves 22 and 25 are closed, and the temperature damper is fully closed. The system simultaneously realizes passenger cabin refrigeration and battery cooling.

[0124] Figure 15 Corresponding to the passenger cabin heating mode using motor waste heat: the shut-off valves 16, 20 and 21 are opened, the shut-off valves 17, 18 and 19 are closed, the expansion valves 22, 23 and 24 are throttled, the expansion valve 25 is closed, the battery water circuit heat exchanger is connected to the motor, and the system absorbs heat from the motor to heat the passenger cabin.

[0125] Next, the passenger cabin-battery simultaneous heating mode is specifically controlled.

[0126] Figure 3 The system composition schematic diagram of this mode is shown, and on the basis of Figure 1 , the composition under this mode is constituted through the opening and closing actions of the expansion valves and the shut-off valves.

[0127] Figure 4 The flowchart under the mode shown is illustrated, and in combination with the flowchart, the passenger cabin-battery simultaneous heating mode is specifically described as follows. Figure 3

[0128] Step 41, first, the blower air volume and the water pump flow are defined to ensure the comfort and heating capacity of the heat pump system. According to the outdoor temperature T au , the inlet air temperature T in and the target outlet air temperature T target , the target blower air volume V target is obtained by table lookup. Then, according to the outdoor temperature T au , the maximum blower air volume V max is obtained by table lookup. V target and V max are compared, and the smaller one is taken as the blower air volume V. According to the outdoor temperature and the battery temperature, the water pump flow V water is obtained by table lookup.

[0129] Step 42, the system calculates the heat demand of the passenger cabin and the battery, respectively, according to the target outlet air temperature, the inlet air temperature, the blower air volume and the battery temperature;

[0130] wherein the heat demand Q​cabin Based on the target air outlet temperature T in the passenger cabin target Inlet air temperature T in Calculate the blower air volume V:

[0131] Q cabin =a*(T target -T in )*V (1)

[0132] Where 'a' is a calibrated fixed coefficient.

[0133] Battery thermal demand Q bat Through battery temperature T bat The calculation yielded:

[0134] Q bat =b*T bat +c (2)

[0135] Where b and c are fixed coefficients.

[0136] Step 43: Compare the heat demand of the passenger compartment and the battery. Based on the comparison results, adjust the opening of expansion valve 22 and expansion valve 24 to control the heat distribution to the passenger compartment and the battery.

[0137] Step 44: When the battery heat demand > passenger cabin heat demand, it indicates that the battery heat demand is the primary control target. The opening of the expansion valve 24 between the battery water heat exchanger 15 and the first end of the second internal heat exchanger 23 is set to the value Φ1 obtained from a table based on the heat demand and external temperature. The initial opening of the expansion valve 22 between the first and second internal heat exchangers 13 and 14 is set as follows:

[0138] Q cabin / Q bat ×Φ1 (3)

[0139] According to the outlet air temperature T out Inlet air temperature T in The blower air volume V is used to calculate the wind-side power Q. air :

[0140] Q air =d*(T) out -T in )*V (4)

[0141] Where d is a fixed coefficient;

[0142] Wind-side power Q air Passenger cabin thermal demand Q cabin After comparison, the opening degree of expansion valve 22 is adjusted in real time. Real-time adjustment means that when Q... air cabin ​- Δ, increase the opening of the expansion valve 22 at a certain rate until Q air > Q cabin - Δ, the wind side power meets the requirements; when Q air > Q cabin + Δ, decrease the opening of the expansion valve 22 at a certain rate until Q air < Q cabin + Δ, the wind side power meets the requirements. Where Δ is the allowable error range.

[0143] Step 45, control the system overall heating capacity with the second expansion valve 23 opening and the compressor speed, and make the entire heat pump system work in a higher efficiency interval.

[0144] According to the outlet water temperature T out water of the battery water circuit heat exchanger, the inlet water temperature T in , and the water pump flow rate V water , the water side power Q water is calculated: water

[0145] Q water = e * (T out water -T in water ) * V water (5)

[0146] Where e is a calibrated parameter.

[0147] The compressor speed is controlled by the water side power as the control target, and PI control is performed.

[0148] The initial value of the second expansion valve 23 opening is set as:

[0149] f-g*Q water / Q bat -h*T au (6)

[0150] Where f, g, and h are all calibrated parameters.

[0151] This setting is to consider both the instantaneous power requirement and the influence of the outside temperature on the best efficiency point. The opening of the second expansion valve 23 is adjusted in real time, that is, when the compressor outlet pressure or temperature is higher than the set safety pressure / temperature, the opening of the second expansion valve 23 is increased at a certain rate until it is lower than the set safety pressure / temperature; when the compressor outlet pressure and temperature are both lower than the set pressure / temperature threshold, the opening of the second expansion valve 23 is decreased at a certain rate until it is higher than the set pressure / temperature threshold.

[0152] The fourth expansion valve 25 is initially set to maximum opening. If the battery water circuit heat exchanger pressure is higher than the set safety pressure, the fourth expansion valve 25 opening is decreased at a certain rate until the battery water circuit heat exchanger pressure is lower than the set safety pressure.

[0153] Step 46: When the passenger cabin heat demand > battery heat demand, it indicates that the passenger cabin heat demand is the main control target at this time. The opening of the expansion valve 22 between the first and second internal heat exchangers 13 and 14 is set to the value Φ2 obtained from the heat demand and external temperature table. The initial opening of the expansion valve 24 between the battery water circuit heat exchanger 15 and the first end of the second internal heat exchanger 23 is set to:

[0154] Q bat / Q cabin ×Φ2 (7)

[0155] The water side power Q water is compared with the battery heat demand Q bat , and the opening of the expansion valve 24 is adjusted in real time. Real-time adjustment refers to when Q water <Q bat -Δ, the opening of the expansion valve 24 is increased at a certain rate until Q water >Q bat -Δ, the water side power meets the requirements; when Q water >Q bat +Δ, the opening of the expansion valve 24 is decreased at a certain rate until Q water <Q bat +Δ, the water side power meets the requirements. Where Δ is the allowable error range.

[0156] Step 47: The second expansion valve 23 opening and the compressor speed are used to control the overall heating capacity of the system, and the entire heat pump system works in a relatively high efficiency range.

[0157] The compressor speed is controlled by the outlet air temperature as the control target, and PI control is performed.

[0158] The initial opening of the second expansion valve 23 is set to:

[0159] i–j*Q air / Q cabin -k*T au (8)

[0160] Where i, j, k are fixed parameters calibrated.

[0161] The setting is to consider the instantaneous power requirement and the influence of the external temperature on the best efficiency point at the same time. The opening of the second expansion valve 23 is adjusted in real time, that is, when the compressor outlet pressure or temperature is higher than the set safety pressure / temperature, the opening of the second expansion valve 23 is increased at a certain rate until it is lower than the set safety pressure / temperature; when the compressor outlet pressure and temperature are both lower than the set pressure / temperature threshold, the opening of the second expansion valve 23 is decreased at a certain rate until it is higher than the set pressure / temperature threshold.

[0162] The opening of the fourth expansion valve 25 is initially set to the maximum, and if the battery water circuit heat exchanger pressure is higher than the set safety pressure, the opening of the fourth expansion valve 25 is decreased at a certain rate until the battery water circuit heat exchanger pressure is lower than the set safety pressure.

[0163] Step 48, because the battery heat demand has higher priority, when the passenger cabin heat demand is the main control target, a certain time is needed to judge whether the water side power reaches the battery demand power.

[0164] Step 49, if the battery demand power cannot be reached, the opening of the expansion valve 22 needs to be decreased at a certain rate until the water side power meets the battery demand.

[0165] Step 50, if the battery demand power can be reached, the system remains in the current control state.

[0166] In the heat pump system of the present application, the aforementioned 12 kinds of operation modes for controlling the passenger cabin and the battery are provided. According to the above-mentioned control method, the mode control of the passenger cabin and the battery simultaneously absorbing heat or simultaneously releasing heat can be realized, that is, the control of 9 kinds of operation modes such as passenger cabin heating, passenger cabin dehumidification, passenger cabin refrigeration, battery heating, battery cooling, passenger cabin heating-battery heating, passenger cabin dehumidification-battery cooling, passenger cabin refrigeration-battery cooling and heating the passenger cabin by using the motor waste heat. In the remaining 3 kinds of modes of passenger cabin heating-battery cooling, passenger cabin dehumidification-battery heating and passenger cabin refrigeration-battery heating, one side of the passenger cabin and the battery absorbs heat and the other side releases heat, and the control method is changed, which includes the opening of the expansion valve 23 for adjusting the energy distribution of the system to the passenger cabin and the battery, the opening of the expansion valves 22 and 24 and the rotation speed of the compressor for controlling the overall performance and efficiency of the system. The specific control method is not described again.

[0167] The technical effect of the present application is that through the switching of the working mode, the heat pump system can simultaneously meet the energy demand of the passenger cabin and the battery, and get rid of the limitation of the traditional heat pump system which still needs PTC to heat the battery, and realize the improvement of energy efficiency.

[0168] Having described the basic concepts, it is obvious that the above-described application is merely an example for the person skilled in the art and does not limit the application. Although not explicitly stated, the person skilled in the art can make various modifications, improvements and adaptations to the application. Such modifications, improvements and adaptations are suggested in the application and still fall within the spirit and scope of the exemplary embodiments of the application.

[0169] Also, the application uses specific terminology with respect to the embodiments of the application. As used herein, the terms "one embodiment," "an embodiment," "some embodiments," and / or "one alternative" are intended to mean that a certain feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. Therefore, use of the terms "in one embodiment" or "in an embodiment" or "in one alternative" or "in some alternatives" or "one alternative" in various places in the specification are not necessarily referring to the same embodiment of the application, nor are separate or alternative embodiments mutually exclusive of one another. Moreover, certain features, structures, or characteristics of one or more embodiments of the application can be combined in any manner.

[0170] Similarly, it is to be noted that, for reasons of brevity and clarity, the description of the embodiments of the application hereinabove has not always listed every single feature of the embodiments of the application, but rather, some features have been grouped together in a single embodiment, drawing or description of the embodiment. This method of disclosure is not to be interpreted as a limitation on the scope of the application, but merely an explanation. Indeed, the described features of the embodiments of the application are less than all of the features of the single embodiments described above.

[0171] Some embodiments use numerical ranges to describe quantities of components, attributes, etc. It should be understood that such numerical ranges described in the embodiments are, in some examples, modified by the word "about". Unless otherwise indicated, "about" indicates that the stated numerical value envisions a variance of ± 20%. Accordingly, numerical parameters in the description and claims are approximations, and thus can vary depending upon the desired properties sought to be obtained by the individual embodiments. In some embodiments, numerical parameters are approximations and are thus understood to be within a range of values that one of ordinary skill in the art would consider analogous to the same. Although the numerical ranges and parameters setting forth the broadest scope of the application are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, can contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0172] While the application has been described with reference to the currently preferred embodiments, those skilled in the art will recognize that various changes can be made in form and detail without departing from the spirit and scope of the application. Therefore, although the application has been described with reference to particular embodiments, it is to be understood that variations and modifications can be affected without departing from the spirit and scope of the application.

Claims

1. A heat pump system comprising a compressor, characterized by, The system comprises: An air circuit control unit arranged in the passenger cabin, comprising a first indoor heat exchanger, a second indoor heat exchanger and an outdoor heat exchanger, and a refrigerant circulating in the air circuit control unit under the driving of the compressor; A water circuit control unit arranged at the battery side, comprising a water pump and a battery water circuit heat exchanger, and circulating water flowing through the battery water circuit heat exchanger and the battery under the driving of the water pump, and transferring heat or cold from the battery water circuit heat exchanger to the battery; The output end of the compressor is connected to the air circuit control unit and the water circuit control unit through a plurality of control switches, realizing the control mode of the passenger cabin and the battery; The plurality of control switches comprise first to fourth expansion valves and first to sixth stop valves; The first end of the first indoor heat exchanger is connected to the battery water circuit heat exchanger through the fourth expansion valve, the second end is connected to the second end of the outdoor heat exchanger through the third stop valve, and the second end is connected to the second end of the second indoor heat exchanger through the first expansion valve; The first end of the second indoor heat exchanger is connected to the first end of the outdoor heat exchanger through the second expansion valve, and the first end is also connected to the first end of the battery water circuit heat exchanger through the third expansion valve, and the second end of the second indoor heat exchanger is connected to the second end of the battery water circuit heat exchanger through the fourth stop valve and the sixth stop valve; The second end of the outdoor heat exchanger is connected to the second end of the compressor through the second stop valve, and the second end of the outdoor heat exchanger is connected between the sixth stop valve and the fourth stop valve through the fifth stop valve; The first end of the compressor is connected between the sixth stop valve and the fourth stop valve, and the second end is connected to the first end of the first indoor heat exchanger through the first stop valve; In the air circuit control unit, the flow direction of the refrigerant is changed by the opening and closing of the first to sixth stop valves, and the refrigerant releases heat on the high-pressure side to the air circuit control unit or the water circuit control unit, and absorbs heat on the low-pressure side to the air circuit control unit or the water circuit control unit, by using the throttling pressure difference of the first to fourth expansion valves, to realize heating or refrigeration.

2. The heat pump system of claim 1, wherein, The control mode further comprises: A passenger cabin control mode and a battery control mode, wherein the passenger cabin control mode comprises any one of passenger cabin refrigeration, heating and dehumidification, and the battery control mode comprises any one of battery refrigeration and heating; The control mode further comprises a combination of one of the passenger cabin control mode and the battery control mode.

3. A control method for the heat pump system according to any one of claims 1-2, characterized in that: Step 1: obtaining the air volume of the air blower and the flow rate of the water pump according to the temperature or humidity requirement; Step 2: calculating the passenger cabin control requirement and the battery control requirement according to the target temperature and the measured temperature, wherein the target temperature comprises the target dew point temperature and the target air outlet temperature of the passenger cabin, and the measured temperature comprises the air inlet temperature and the battery temperature; Step 3: adjusting the on-off of each stop valve and expansion valve according to the passenger cabin control requirement and the battery control requirement, and controlling to select one system operation mode. Step four, compare the passenger cabin regulation requirement and battery regulation requirement, when the passenger cabin and battery regulation requirement is heat absorption at the same time or heat release at the same time, the second expansion valve is regulated according to the compressor discharge temperature and pressure, and the first and third expansion valves are regulated to control energy output distribution; When the passenger cabin and battery regulation requirement is heat release and heat absorption respectively, the second expansion valve is regulated to control energy output distribution, and the first and third expansion valves are regulated according to the compressor discharge temperature and pressure.

4. The control method according to claim 3, characterized by, In the second step, the passenger cabin regulation demand includes a passenger cabin target energy demand Q cabin is: Q cabin = a*(T target - T in )*V (1) Wherein, a is a fixed coefficient calibrated, T target is the target air outlet temperature or target dew point temperature of the passenger compartment, T in is the inlet air temperature, and V is the air volume of the air blower The battery regulation demand includes a battery target energy demand Q bat is: Q bat = b*T bat + c (2) where b and c are fixed coefficients, and T is the battery temperature bat calculated The passenger cabin target dew point temperature is obtained by looking up a table according to the outside temperature and air humidity.

5. The control method according to claim 4, characterized in that, The system operation mode of step three includes a passenger cabin heating mode, a passenger cabin dehumidification mode, a passenger cabin refrigeration mode, a battery heating mode, a battery cooling mode, a passenger cabin-battery simultaneous heating mode, a passenger cabin heating-battery cooling mode, a passenger cabin dehumidification-battery heating mode, a passenger cabin dehumidification-battery cooling mode, a passenger cabin refrigeration-battery heating mode, a passenger cabin refrigeration-battery cooling mode, and a mode of heating the passenger cabin by using motor waste heat. In the passenger cabin heating mode, the first and fifth stop valves are opened, the second, third, fourth and sixth stop valves are closed, the first and second expansion valves are throttled, and the third and fourth expansion valves are closed. In the passenger cabin dehumidification mode, the first, third and fourth stop valves are opened, the second, fifth and sixth stop valves are closed, the second expansion valve is throttled, and the first, third and fourth expansion valves are closed. In the passenger cabin refrigeration mode, the second and fourth stop valves are opened, the first, third, fifth and sixth stop valves are closed, the second expansion valve is throttled, and the first, third and fourth expansion valves are closed. In the battery heating mode, the first and fifth stop valves are opened, the second, third, fourth and sixth stop valves are closed, the second and fourth expansion valves are throttled, the third expansion valve is opened, and the first expansion valve is closed. In the battery cooling mode, the second and sixth stop valves are opened, the first, third, fourth and fifth stop valves are closed, the second expansion valve is throttled, the third expansion valve is opened, and the first and fourth expansion valves are closed. In the passenger cabin heating-battery heating mode, the first and fifth stop valves are opened, the second, third, fourth and sixth stop valves are closed, and the first, second, third and fourth expansion valves are throttled. In the passenger cabin heating-battery cooling mode, when the required heat of the passenger cabin is close to the required cooling of the battery, the first and sixth stop valves are opened, the second, third, fourth and fifth stop valves are closed, the first and third expansion valves are throttled, and the second and fourth expansion valves are closed; when the required heat of the passenger cabin is greater than the required cooling of the battery, the first, fifth and sixth stop valves are opened, the second, third and fourth stop valves are closed, the first, second and third expansion valves are throttled, and the fourth expansion valve is closed; when the required heat of the passenger cabin is less than the required cooling of the battery, the first and second and sixth stop valves are opened, the third, fourth and fifth stop valves are closed, the first, second and third expansion valves are throttled, and the fourth expansion valve is closed. In the passenger cabin dehumidification-battery heating mode, the first, third and fourth stop valves are opened, the second, fifth and sixth stop valves are closed, the second, third and fourth expansion valves are throttled, and the first expansion valve is closed. In the passenger cabin dehumidification-battery cooling mode, the first, third, fourth and sixth stop valves are opened, the second and fifth stop valves are closed, the second and third expansion valves are throttled, and the first and fourth expansion valves are closed. In the passenger cabin refrigeration-battery heating mode, when the required cold quantity of the passenger cabin is similar to the required heat quantity of the battery, the first and fourth stop valves are opened, the second, third, fifth and sixth stop valves are closed, the third and fourth expansion valves are throttled, and the first and second expansion valves are closed; when the required cold quantity of the passenger cabin is less than the required heat quantity of the battery, the first, fourth and fifth stop valves are opened, the second, third and sixth stop valves are closed, the second, third and fourth expansion valves are throttled, and the first expansion valve is closed; when the required cold quantity of the passenger cabin is greater than the required heat quantity of the battery, the first, second and fourth stop valves are opened, the third, fifth and sixth stop valves are closed, the second, third and fourth expansion valves are throttled, and the first expansion valve is closed; In the passenger cabin refrigeration-battery cooling mode, the second, fourth and sixth stop valves are opened, the first, third and fifth stop valves are closed, the second and third expansion valves are throttled, and the first expansion valve is closed; In the passenger cabin heating mode using motor waste heat, the first, fifth and sixth stop valves are opened, the second, third and fourth stop valves are closed, the first, second and third expansion valves are throttled, the fourth expansion valve is closed, the battery water circuit heat exchanger is connected with the motor, and the system absorbs heat from the motor.

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