A battery direct cooling and direct heating CO2 vehicle thermal management system and control method thereof

Abstract

The present invention discloses a battery direct cooling and direct heating CO2 vehicle thermal management system and a control method thereof, wherein the system comprises: a compressor, an outdoor heat exchanger, a regenerator, a direct cooling and direct heating heat exchange cold plate, a gas-liquid separator, an HVAC module, an indoor fan, an outdoor fan, a first connecting pipe, a second connecting pipe and a third connecting pipe. The present invention can realize the control of passenger compartment direct cooling and battery direct cooling by controlling the outlet dryness of the indoor secondary heat exchanger and the inlet temperature of the direct cooling and direct heating heat exchange cold plate; the control of passenger compartment heating and battery direct cooling or direct heating can be realized by controlling the third two-way full-pass throttle valve; and a large series system structure with different dehumidification amounts can be realized by combining solenoid valves. The present invention can avoid technical problems in the battery direct cooling and direct heating system, such as difficult control of flow rate, difficult control of battery heat exchange cold plate outlet dryness, easy dry burning, and large temperature glide of supercritical CO2 direct heating causing uneven battery heating.

Description

Technical Field

[0001] The invention belongs to the technical field of heat pump air conditioning and thermal management of new energy vehicles, and particularly relates to a battery direct cooling and direct heating CO 2 A vehicle thermal management system and a control method thereof. Background Art

[0002] New energy vehicles have become a national strategy that shoulders multiple historical missions such as future travel, industrial development, energy security, and air quality improvement. The industry is also facing realistic problems such as fierce market competition, insufficient development momentum, shortage of technical reserves, and an imperfect industrial chain. The freon-based working fluid currently used in large quantities in new energy vehicles has a strong greenhouse effect. Transcritical CO 2 The thermal management system of the cycle is of great significance to the emission reduction of gases with strong thermal effect.

[0003] At present, new energy vehicles transcritical CO 2 In the thermal management system, the battery is basically cooled by a secondary circuit (i.e., water cooling). The battery is cooled or heated by heat exchange with cold or hot water, which is obtained by transcritical CO 2 Although the above existing solutions have improved efficiency compared to electric heating, the heat exchange loss of the secondary heat exchange is large, and the heat capacity of water is relatively high, resulting in obvious thermal hysteresis, enhanced thermal management time, and large heat loss for automotive applications such as frequent start-stop.

[0004] Direct cooling and direct heating technology is to directly convert CO 2 The working fluid is passed into the battery heat exchange cold plate to achieve direct cooling or heating of the battery, which can greatly improve the heat exchange efficiency and alleviate the energy waste and extended thermal management time caused by thermal hysteresis. However, direct cooling and direct heating technology has not been well promoted in engineering. The main reasons include: on the one hand, since the two-phase working fluid directly exchanges heat with the battery, too high working fluid dryness will affect the heat exchange efficiency, especially when the dryness exceeds a certain value of about 0.8 (the specific critical value is related to the design of the heat exchange cold plate), the heat exchange efficiency drops sharply, resulting in uneven cooling and even dry burning; on the other hand, the direct cooling and direct heating technology and the passenger compartment often have different evaporation temperatures, the dual evaporation temperature system is difficult to control, and the two-phase cooling flow is not easy to control. In summary, there is an urgent need to develop new direct cooling and direct heating CO2 batteries. 2 A vehicle thermal management system and a control method thereof. Summary of the invention

[0005] The purpose of the present invention is to provide a battery direct cooling and direct heating CO 2A vehicle thermal management system and control method thereof are provided to solve one or more of the above-mentioned technical problems. The present invention can solve the bottlenecks of low-temperature endurance attenuation and high-temperature endurance attenuation, realize refined thermal management, and greatly improve the direct cooling and direct heating stability.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a battery direct cooling and direct heating CO 2 A vehicle thermal management system, comprising: a compressor, an outdoor heat exchanger, a regenerator, a direct cooling and direct heating heat exchange cold plate, a gas-liquid separator, an HVAC module, an indoor fan, an outdoor fan, a first connecting pipe, a second connecting pipe and a third connecting pipe; wherein the HVAC module comprises: an air duct, an indoor main heat exchanger and an indoor secondary heat exchanger; the air duct is provided with an air inlet and an air return port, the air inlet is provided with the indoor fan, and the air return port is provided with a damper;

[0008] The outlet of the compressor is connected to the inlet of the first heat exchange channel of the regenerator via the first solenoid valve and the first heat exchange channel of the outdoor heat exchanger in sequence; the outlet of the first heat exchange channel of the regenerator is divided into two paths, one path is connected to the inlet of the compressor via the first two-way full-through throttle valve, the first heat exchange channel of the indoor main heat exchanger, the sixth solenoid valve, the gas-liquid separator and the second heat exchange channel of the regenerator in sequence, and the other path is connected to the outlet of the compressor via the second two-way full-through throttle valve, the direct-cooling and direct-heating heat exchange cold plate, the third two-way full-through throttle valve, the first heat exchange channel of the indoor secondary heat exchanger and the second solenoid valve in sequence;

[0009] The outdoor fan is arranged at the inlet or outlet of the second heat exchange channel of the outdoor heat exchanger;

[0010] A fifth solenoid valve is provided on the first communicating pipe, one end of the first communicating pipe is connected to the communicating pipe between the second solenoid valve and the first heat exchange channel of the indoor secondary heat exchanger, and the other end is connected to the communicating pipe between the sixth solenoid valve and the first heat exchange channel of the indoor main heat exchanger;

[0011] The second communicating pipe is provided with a fourth solenoid valve, one end of the second communicating pipe is connected to the communicating pipe between the sixth solenoid valve and the gas-liquid separator, and the other end is connected to the communicating pipe between the second solenoid valve and the first communicating pipe;

[0012] The third communicating pipe is provided with a third solenoid valve, one end of the third communicating pipe is connected to the communicating pipe between the first solenoid valve and the outdoor heat exchanger, and the other end of the third communicating pipe is connected to the communicating pipe between the fourth solenoid valve and the gas-liquid separator.

[0013] The present invention provides a battery direct cooling and direct heating CO 2Control method of vehicle thermal management system, when passenger compartment is cooled and battery is in direct cooling mode: the first solenoid valve, the fourth solenoid valve, and the fifth solenoid valve are opened, and the second solenoid valve, the third solenoid valve, and the sixth solenoid valve are closed; CO 2 The working fluid is compressed to a high-pressure and high-temperature state by the compressor, and then flows through the outdoor heat exchanger and the regenerator in sequence and is divided into two paths. One path is throttled to the evaporation temperature through the first two-way full-pass throttle valve and enters the indoor main heat exchanger to cool the passenger cabin; the other path is first throttled to a preset intermediate temperature through the second two-way full-pass throttle valve, enters the direct cooling and direct heating heat exchanger cold plate to cool the battery, and then is throttled and cooled to the same evaporation temperature as the indoor main heat exchanger through the third two-way full-pass throttle valve, and flows into the indoor secondary heat exchanger to cool the passenger cabin; after the two paths are merged, they return to the compressor through the fourth solenoid valve, the gas-liquid separator and the regenerator.

[0014] The present invention is further improved, and the control method in the passenger compartment cooling and battery direct cooling mode includes the following steps:

[0015] Note the outlet two-phase CO of the direct cooling and direct heating heat exchange cold plate 2 The temperature is T2, the battery temperature is T1, the air outlet temperature of the return air outlet of the passenger compartment HVAC module is T3, the working fluid temperature at one end of the indoor main heat exchanger close to the first two-way full-pass throttle valve is T6, the working fluid temperature at the other end is T4, and the exhaust pressure of the compressor is P;

[0016] The compressor establishes a PID regulation relationship with T3, T3 is the target quantity, and the compressor speed is the control quantity;

[0017] The second two-way full-pass throttle valve establishes a PID adjustment relationship with T2, T2 is the target quantity, and the opening of the second two-way full-pass throttle valve is the control quantity;

[0018] A PID adjustment relationship is established between the first two-way full-pass throttle valve and the superheat of T4, with the superheat being the target variable and the opening of the first two-way full-pass throttle valve being the control variable, and the outlet superheat of the indoor main heat exchanger is always ensured to be 1;

[0019] A PID regulation relationship is established between the third two-way full-pass throttle valve and the compressor exhaust pressure P, where P is the target quantity and the opening of the third two-way full-pass throttle valve is the control quantity.

[0020] The present invention is further improved, in the passenger compartment cooling and battery direct cooling mode, the value of T2 is related to the ambient temperature and the battery temperature T1; wherein,

[0021] If the battery temperature T1≤a℃ and the ambient temperature≤b℃, then T2=(20-T1+a)℃;

[0022] If the battery temperature T1 ≤ a℃ and the ambient temperature is greater than b℃, the value of T2 is 20℃;

[0023] If the battery temperature a℃<T1≤(a+10)℃, then T2=15℃;

[0024] If the battery temperature is (a+10)℃<T1≤(a+15)℃, then the value of T2 is 10℃;

[0025] If the battery temperature T1> (a+15)℃, the first two-way full-pass throttle valve and the indoor fan are closed, the compressor runs at the maximum speed, and the second two-way full-pass throttle valve changes from controlling the temperature of T2 to controlling the exhaust pressure to 12MPa;

[0026] In the passenger compartment heating and battery direct heating mode, when T5 is less than 60°C, the third two-way full-pass throttle valve (8) is in a fully open state; when T5 is greater than or equal to 60°C, the value of T2 is 55°C.

[0027] The present invention provides a battery direct cooling and direct heating CO 2 Control method of vehicle thermal management system, in passenger compartment heating and battery direct heating or direct cooling mode: the first solenoid valve, the fourth solenoid valve, and the fifth solenoid valve are closed, and the second solenoid valve, the third solenoid valve, and the sixth solenoid valve are opened; CO 2 The working fluid is compressed to a high-pressure and high-temperature state by the compressor, and is divided into two paths after passing through the second solenoid valve. One path flows into the indoor main heat exchanger through the fifth solenoid valve to heat the passenger compartment, and the other path first flows into the indoor secondary heat exchanger to heat the passenger compartment, and then enters the battery direct cooling and direct heating heat exchanger plate through the third two-way full-pass throttle valve to heat or cool the battery; the two paths of working fluid are throttled and cooled through the first two-way full-pass throttle valve and the second two-way full-pass throttle valve respectively and flow into the outdoor heat exchanger, absorb the heat of the air, and then return to the compressor through the third solenoid valve, the gas-liquid separator and the regenerator.

[0028] The present invention is further improved, and the control method in the passenger compartment heating and battery direct heating or direct cooling mode includes the following steps:

[0029] The working medium temperature after the third two-way full-pass throttle valve is T2, the outlet temperature of the indoor secondary heat exchanger is T5, the battery temperature is T1, the outlet temperature of the return air outlet of the HVAC module in the passenger compartment is T3, and the exhaust pressure of the compressor is P;

[0030] The compressor establishes a PID regulation relationship with T3, T3 is the target quantity, and the compressor speed is the control quantity;

[0031] The third two-way full-pass throttle valve establishes a PID adjustment relationship with T2, T2 is the target quantity, and the opening of the third two-way full-pass throttle valve is the control quantity;

[0032] A PID regulating relationship is established between the first two-way full-pass throttle valve and the exhaust pressure P, where P is the target value and the opening of the first two-way full-pass throttle valve is the control value;

[0033] A PID regulation relationship is established between the second two-way full-pass throttle valve and the battery temperature T1, where T1 is the target value and the opening of the second two-way full-pass throttle valve is the control value.

[0034] The present invention is further improved, in the passenger compartment heating and battery direct heating or direct cooling mode, the value of T2 is related to the ambient temperature and the battery temperature T1; wherein,

[0035] Battery temperature T1≤a℃, then T2=(20-T1+a)℃;

[0036] If the battery temperature a℃<T1≤(a+10)℃, then T2=15℃;

[0037] If the battery temperature is (a+10)℃<T1≤(a+15)℃, then the value of T2 is 10℃;

[0038] If the battery temperature T1>(a+15)℃, the first two-way full-pass throttle valve and indoor fan are closed, and the second two-way full-pass throttle valve is in the full-pass state. The compressor runs at the maximum speed, and the third two-way full-pass throttle valve self-controls the temperature of T2 and changes to control the exhaust pressure to 12MPa.

[0039] The present invention provides a battery direct cooling and direct heating CO 2 A control method for a vehicle thermal management system, dehumidification and battery direct heating or direct heating mode, including:

[0040] 1) When the ambient temperature is less than or equal to 10℃ for dehumidification and defogging, the second solenoid valve, the third solenoid valve, and the sixth solenoid valve are opened, and the first solenoid valve, the fourth solenoid valve, and the fifth solenoid valve are closed; CO 2 The working fluid is compressed to a high-pressure and high-temperature state by the compressor, and then flows through the second solenoid valve, the indoor secondary heat exchanger, the third two-way full-pass throttle valve, the battery direct cooling and direct heating heat exchange plate, and the second two-way full-pass throttle valve in sequence, and then is divided into two paths. One path flows into the outdoor heat exchanger to absorb environmental heat, and the other path flows into the indoor main heat exchanger through the first two-way full-pass throttle valve. The first two-way full-pass throttle valve is in a full-pass state. After the indoor temperature is reduced and dehumidified, it flows into the gas-liquid separator through the sixth solenoid valve, and merges with the other working fluid in the gas-liquid separator through the third solenoid valve and returns to the compressor;

[0041] b) When the ambient temperature is greater than 10℃ for dehumidification and defogging, the second solenoid valve and the sixth solenoid valve are opened, and the first solenoid valve, the third solenoid valve, the fourth solenoid valve and the fifth solenoid valve are closed; CO 2 The working fluid is compressed to a high-pressure and high-temperature state by the compressor, and flows through the second solenoid valve, the indoor secondary heat exchanger, the third two-way full-pass throttle valve, the battery direct cooling and direct heating heat exchange plate, the second two-way full-pass throttle valve, the first two-way full-pass throttle valve into the indoor main heat exchanger. After the indoor temperature is reduced and dehumidified, it flows into the gas-liquid separator through the sixth solenoid valve and returns to the compressor.

[0042] The control method in the dehumidification and battery direct heating or direct heating mode further improved by the present invention comprises the following steps:

[0043] The working medium temperature after the third two-way full-pass throttle valve is T2, the working medium temperature at one end of the indoor main heat exchanger close to the first two-way full-pass throttle valve is T6, the air outlet temperature of the return air outlet of the HVAC module in the passenger compartment is T3, and the exhaust pressure of the compressor is P;

[0044] The compressor establishes a PID regulation relationship with T3, T3 is the target quantity, and the compressor speed is the control quantity;

[0045] A PID regulation relationship is established between the third two-way full-pass throttle valve and the temperature T2, T2 is the target value, and the opening of the third two-way full-pass throttle valve is the control value;

[0046] The second two-way full-pass throttle valve establishes a PID adjustment relationship with T6, T6 is the target value, and the compressor exhaust pressure P is the protection value under this control; the first two-way full-pass throttle valve maintains a full-pass state.

[0047] In the control method of the dehumidification and battery direct heating or direct heating mode further improved by the present invention,

[0048] When the exhaust pressure P is less than 12MPa, the value of T6 is 0;

[0049] When the exhaust pressure P≥12MPa, the PID control logic relationship between the second two-way full-pass throttle valve and T6 is disconnected, and the second two-way full-pass throttle valve is changed to establish a control relationship with the exhaust pressure, and the exhaust pressure is always maintained at 12MPa.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] The invention provides a new energy vehicle transcritical CO2 battery direct cooling and direct heating system. 2 In the thermal management system, the first two-way full-pass throttle valve, the direct cooling and direct heating heat exchange cold plate, the third two-way full-pass throttle valve, and the indoor secondary heat exchanger are connected in series with the second two-way throttle valve and the main heat exchanger in series to form a parallel structure, which can solve the bottlenecks of low-temperature endurance attenuation and high-temperature endurance attenuation, realize refined thermal management, greatly improve the stability of direct cooling and direct heating, and greatly expand CO 2 Technical application of direct cooling and direct heating. To further explain, the battery direct cooling and direct heating heat exchange cold plate is connected in series with the indoor secondary heat exchanger through a two-way full-pass throttle valve. This is mainly to solve the problems of difficult control of battery direct cooling flow and uncontrollable dryness of the heat exchange cold plate outlet leading to dry burning of the battery. It is also to solve the problem of transcritical CO during direct heating. 2 Large temperature glide causes extremely uneven battery heating.

[0052] In the control method of the present invention, by controlling CO 2The outlet dryness of the secondary heat exchanger and the inlet temperature of the direct cooling and direct heating heat exchange cold plate are used to control the direct cooling of the passenger compartment and the direct cooling of the battery; the heating of the passenger compartment and the direct cooling / heating of the battery are controlled by the control of the third two-way full-pass throttle valve; the large series system structure under different dehumidification amounts is realized by the combination of solenoid valves; based on the above control method, the bottlenecks of low-temperature endurance attenuation and high-temperature endurance attenuation can be solved, and refined thermal management can be achieved, which can greatly improve the stability of direct cooling and direct heating, and can greatly expand CO 2 Direct cooling and direct heating technology application. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art; obviously, the drawings described below are some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0054] Figure 1 Schematic diagram of a battery direct cooling and direct heating CO2 vehicle thermal management system according to an embodiment of the present invention;

[0055] In the figure, 1. compressor; 2. outdoor heat exchanger; 3. regenerator; 4. first two-way full-pass throttle valve; 5. second two-way full-pass throttle valve; 6. indoor main heat exchanger; 7. indoor secondary heat exchanger; 8. third two-way full-pass throttle valve; 9. direct cooling and direct heating heat exchange cold plate; 10. first solenoid valve; 11. second solenoid valve; 12. third solenoid valve; 13. fourth solenoid valve; 14. gas-liquid separator; 15. battery; 16. HVAC module; 17. fifth solenoid valve; 18. sixth solenoid valve; 19. indoor fan; 20. outdoor fan. DETAILED DESCRIPTION

[0056] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0057] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0058] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0059] See also Figure 1 A battery direct cooling and direct heating CO according to an embodiment of the present invention 2 The vehicle thermal management system includes: a compressor 1, an outdoor heat exchanger 2, a regenerator 3, an HVAC module 16 (heating, ventilation and air conditioning module), an indoor main heat exchanger 6, an indoor secondary heat exchanger 7, a first two-way full-pass throttle valve 4, a second two-way full-pass throttle valve 5, a third two-way full-pass throttle valve 8, a direct cooling and direct heating heat exchange cold plate 9, a first solenoid valve 10, a second solenoid valve 11, a third solenoid valve 12, a fourth solenoid valve 13, a gas-liquid separator 14, a battery 15, a fifth solenoid valve 17, a sixth solenoid valve 18, an indoor fan 19 and an outdoor fan 20.

[0060] Among them, the compressor 1 is connected to the first solenoid valve 10, the outdoor heat exchanger 2, and the regenerator 3 in sequence. The regenerator 3 is connected to the first two-way full-pass throttle valve 4 and the second two-way full-pass throttle valve 5 respectively. The first two-way full-pass throttle valve 4 is connected to the fifth solenoid valve 17 and the sixth solenoid valve 18 respectively through the indoor main heat exchanger 6. The second two-way full-pass throttle valve 5 is connected to the direct cooling and direct heating heat exchange cold plate 9, the third two-way full-pass throttle valve 8, and the indoor secondary heat exchanger 7 in sequence, and then connected to the fifth solenoid valve 17, the fourth solenoid valve 13, and the second solenoid valve 11 respectively. The sixth solenoid valve 18 is connected to the fourth solenoid valve 13 and the gas-liquid separator 14 respectively; the outlet of the gas-liquid separator 14 is connected to the suction end of the compressor 1 through the regenerator 3, the second solenoid valve 11 is connected between the compressor 1 and the first solenoid valve 10, one end of the third solenoid valve 12 is connected to the first solenoid valve 10 and the outdoor heat exchanger 2, and the other end is connected between the fourth solenoid valve 13 and the gas-liquid separator 14.

[0061] In the embodiment of the present invention, the battery direct cooling and direct heating heat exchange cold plate is connected in series with the indoor secondary heat exchanger 7 through a two-way full-pass throttle valve, mainly to solve the problems of difficult control of battery direct cooling flow, uncontrollable dryness of the heat exchange cold plate outlet leading to dry burning of the battery, and also to solve the problem of transcritical CO 2 Large temperature glide causes extremely uneven battery heating.

[0062] In the preferred embodiment of the present invention, the battery is directly cooled and heated by CO 2 The indoor main heat exchanger 6 and the indoor secondary heat exchanger 7 of the vehicle thermal management system must meet the following conditions: under the same working conditions (calculated according to the designed severe working conditions), the heat exchange capacity of the indoor main heat exchanger 6 shall not be less than the heat exchange capacity of the indoor secondary heat exchanger 7; the heat exchange capacity of the indoor secondary heat exchanger 7 shall not be less than 1 / X of the heat exchange capacity of the indoor main heat exchanger 6; the value of X is related to the maximum heat generation of the battery.

[0063] The embodiment of the present invention is specifically exemplary, under the normal operating conditions of the design conditions, under the non-battery warning conditions, the maximum calorific value of the battery is Q, under the design conditions that can ensure battery cooling and passenger compartment direct cooling comfort, the initial X value is taken as 3, and the simulation operation is performed according to the control mode of passenger compartment cooling and battery direct cooling, and the outlet dryness of the direct cooling and direct heat exchange cold plate is recorded as x. If x≤0.8, X is kept at 0.5; if x>0.8, X is subtracted by 0.1 and the above steps are repeated until x≤0.8 or X=1. The specific operating condition value is related to the design of different enterprises.

[0064] The battery direct cooling and direct heating CO provided in the embodiment of the present invention 2 The main operating modes of the vehicle thermal management system include: passenger compartment cooling and battery direct cooling mode, passenger compartment heating and battery direct heating mode, passenger compartment heating and battery direct cooling mode, dehumidification and defogging and battery direct heating mode, dehumidification and defogging and battery direct cooling mode; different control methods are used in different operating modes.

[0065] In the control method of the embodiment of the present invention, the passenger compartment cooling and battery direct cooling mode is: the first solenoid valve 10, the fourth solenoid valve 13, and the fifth solenoid valve 17 are opened, the second solenoid valve 11, the third solenoid valve 12, and the sixth solenoid valve 18 are closed, and the CO 2 The working fluid is compressed to a high-pressure and high-temperature state by the compressor 1, and flows through the outdoor heat exchanger 2 and the regenerator 3 in sequence, and then is divided into two paths. One path is directly throttled to the evaporation temperature and enters the indoor main heat exchanger 6 to cool the passenger compartment; the other path is first partially throttled to an intermediate temperature, enters the direct cooling and direct heating heat exchange cold plate 9 to cool the battery 15, and then is further throttled and cooled to the same evaporation temperature in the main heat exchanger through the full-through throttle valve, and flows into the secondary heat exchanger to further cool the passenger compartment; after the two paths are merged, they return to the compressor 1 through the fourth solenoid valve 13, the gas-liquid separator 14, and the regenerator 3.

[0066] In the embodiment of the present invention, the control method of the passenger compartment cooling + battery direct cooling mode is as follows: the outlet two-phase CO 2 The temperature is T2, the battery temperature is T1, the air outlet temperature of the passenger compartment HVAC module 16 is T3, the working medium temperature at one end of the indoor main heat exchanger 6 close to the first two-way full-pass throttle valve 4 is T6, and the working medium temperature at the other end is T4, the working medium temperature at one end of the indoor secondary heat exchanger 7 close to the third two-way full-pass throttle valve 8 is T5, and the exhaust pressure of the compressor 1 is P; the control method includes: the compressor 1 establishes a PID adjustment relationship with T3, T3 is the target quantity, and the compressor speed is the control quantity; the second two-way full-pass throttle valve 5 establishes a PID adjustment relationship with T2, T2 is the target quantity, and the opening degree of the second two-way full-pass throttle valve 5 is the control quantity ; A PID adjustment relationship is established between the first two-way full-pass throttle valve 4 and the outlet superheat of the indoor main heat exchanger 6, that is, a control relationship is established for the superheat of T4, the superheat is the target variable, the opening of the first two-way full-pass throttle valve 4 is the control quantity, and the outlet superheat of the main heat exchanger is always guaranteed to be 1, so as to ensure that the outlet of the indoor secondary heat exchanger 7 is in a micro-two-phase state, and indirectly ensure that the outlet of the battery direct cooling and direct heating heat exchange cold plate 9 is always in a two-phase state to prevent the battery from burning dry; a PID adjustment relationship is established between the third two-way full-pass throttle valve 8 and the compressor exhaust pressure P, P is the target quantity, and the opening of the third two-way full-pass throttle valve 8 is the control quantity. Explanation by way of example, T3 is the air supply temperature set by the car company according to different needs; P is the optimal pressure under the current working conditions, and its acquisition method includes but is not limited to the empirical correlation method and the intelligent optimization control method; T1 temperature is the safe operating temperature of the battery under different working conditions, which is also a quantity set by the car company.

[0067] In the control method of the passenger compartment cooling and battery direct cooling mode in the embodiment of the present invention: the value of T2 is related to the ambient temperature and the battery temperature T1. If the battery temperature T1≤a℃ (the recommended value of a is 35), and the ambient temperature≤b℃ (the recommended value of b is 35), then T2=(20-T1+a)℃; if the battery temperature T1≤a℃, and the ambient temperature is greater than b℃, then the value of T2 is 20℃; if the battery temperature a℃<T1≤(a+10)℃, then T2=15℃; if the battery temperature (a+10)℃<T1≤(a+15)℃, then the value of T2 is 10℃; if the battery temperature T1>(a+15)℃, close the first two-way full-pass throttle valve 4, and turn off the fan, the compressor 1 runs at the maximum speed, and the second two-way full-pass throttle valve 5 no longer controls the temperature of T2, but controls the exhaust pressure to 12MPa instead.

[0068] A battery direct cooling and direct heating CO2 2The control method of the vehicle thermal management system, the passenger compartment heating and battery direct heating mode is: the first solenoid valve 10, the fourth solenoid valve 13, the fifth solenoid valve 17 are closed, the second solenoid valve 11, the third solenoid valve 12, the sixth solenoid valve 18 are opened, CO 2 The working fluid is compressed to a high-pressure and high-temperature state by the compressor 1, and then passes through the second solenoid valve 11 and is divided into two paths. One path flows into the indoor main heat exchanger 6 through the fifth solenoid valve 17 to heat the passenger compartment, and the other path first flows into the indoor secondary heat exchanger 7 to heat the passenger compartment, and then enters the direct cooling and direct heating heat exchange cold plate 9 through the third two-way full-pass throttle valve 8 to heat or cool the battery 15. The opening degree of the third two-way full-pass throttle valve 8 is controlled according to the specific situation or fully opened, mainly to prevent the high temperature CO 2 The working fluid directly enters the battery direct cooling and direct heating heat exchange cold plate, which is harmful to the heating temperature of some batteries. In order to avoid the working fluid in the supercritical large slip state from flowing into the heat exchange cold plate, causing extremely uneven heating of the battery, the two working fluids are throttled and cooled through the first two-way full-pass throttle valve 4 and the second two-way full-pass throttle valve 5 respectively and flow into the outdoor heat exchanger 2. After absorbing the heat of the air, they return to the compressor 1 through the third solenoid valve 12 and the gas-liquid separator 14.

[0069] In the passenger compartment heating and battery direct cooling mode of the embodiment of the present invention, the opening and closing states of all valves are consistent with the passenger compartment heating and battery direct heating mode, and the throttling degree of the third two-way full-pass throttle valve 8 is increased, so that the subsequent CO 2 The temperature is lowered to achieve the purpose of direct cooling.

[0070] In the embodiment of the present invention, the control method of the passenger compartment heating + battery direct heating mode and the passenger compartment heating + battery direct cooling mode is as follows: T2 after the third two-way full-pass throttle valve 8, the outlet temperature of the indoor secondary heat exchanger 7 is T5, the battery temperature is T1, the air outlet temperature of the passenger compartment HVAC module 16 is T3, and the exhaust pressure of the compressor 1 is P. Then the control method includes the following steps: the compressor 1 establishes a PID adjustment relationship with T3, T3 is the target quantity, and the speed of the compressor 1 is the control quantity; the third two-way full-pass throttle valve 8 establishes a PID adjustment relationship with the temperature T2, T2 is the target quantity, and the opening of the third two-way full-pass throttle valve 8 is the control quantity; the first two-way full-pass throttle valve 4 establishes a PID adjustment relationship with the exhaust pressure P, P is the target quantity, and the opening of the first two-way full-pass throttle valve 4 is the control quantity; the second two-way full-pass throttle valve 5 establishes a PID adjustment relationship with the battery temperature T1, T1 is the target quantity, and the opening of the second two-way full-pass throttle valve 5 is the control quantity. Among them, T3 is the air supply temperature set by the car company according to different needs; P is the optimal pressure under the current working conditions, and its acquisition method includes but is not limited to the empirical correlation method and the intelligent optimization control method; the value of the battery temperature T1 is also set by the company according to the application range.

[0071] In the passenger compartment heating and battery direct heating mode control method of the embodiment of the present invention: when T5<c℃ (the recommended value of c is 60), the third two-way full-pass throttle valve 8 is in a fully open state; when T5≥c℃, the value of T2 is 55.

[0072] In the control method of the passenger compartment heating + battery direct cooling mode of the embodiment of the present invention: the value of T2 is related to the ambient temperature and the battery temperature T1. If the battery temperature T1≤a℃ (the recommended value of a is 35), then T2=(20-T1+a)℃; if the battery temperature a℃<T1≤(a+10)℃, then T2=15℃; if the battery temperature (a+10)℃<T1≤(a+15)℃, then the value of T2 is 10℃; if the battery temperature T1>(a+15)℃, the first two-way full-pass throttle valve 4 is closed, the second two-way full-pass throttle valve 5 is in a full-pass state, and the indoor fan 19 is closed, the compressor 1 runs at the maximum speed, and the third two-way full-pass throttle valve 8 no longer controls the temperature of T2, but controls the exhaust pressure to 12MPa instead.

[0073] The dehumidification and battery direct heating mode of the embodiment of the present invention includes:

[0074] a) When the ambient temperature is less than or equal to 10°C and dehumidification and defogging are required, the second solenoid valve 11, the third solenoid valve 12, and the sixth solenoid valve 18 are opened, and the first solenoid valve 10, the fourth solenoid valve 13, and the fifth solenoid valve 17 are closed. 2 The working fluid is compressed to a high-pressure and high-temperature state by the compressor 1, and flows through the second solenoid valve 11, the indoor secondary heat exchanger 7, the third two-way full-pass throttle valve 8, the direct cooling and direct heating heat exchange cold plate 9, and the second two-way full-pass throttle valve 5 in sequence, and then is divided into two paths, one of which flows into the outdoor heat exchanger 2 to absorb environmental heat, and the other flows into the indoor main heat exchanger 6 through the first two-way full-pass throttle valve 4. At this time, the first two-way full-pass throttle valve 4 is in a full-pass state. After cooling and dehumidifying indoors, it flows into the gas-liquid separator 14 through the sixth solenoid valve 18, and merges with the other working fluid in the gas-liquid separator 14 through the third solenoid valve 12, and returns to the compressor 1. The full-pass throttle valve in this mode determines whether it is in a full-pass or partial throttling state depending on the outlet temperature of the indoor secondary heat exchanger 7.

[0075] b) When the ambient temperature is greater than 10°C and dehumidification and defogging are required, the second solenoid valve 11 and the sixth solenoid valve 18 are opened, the first solenoid valve 10, the third solenoid valve 12, the fourth solenoid valve 13 and the fifth solenoid valve 17 are closed, and CO 2The working fluid is compressed to a high-pressure and high-temperature state by the compressor 1, and flows through the second solenoid valve 11, the indoor secondary heat exchanger 7, the third two-way full-pass throttle valve 8, the direct cooling and direct heating heat exchange cold plate 9, the second two-way full-pass throttle valve 5, the first two-way full-pass throttle valve 4, and flows into the indoor main heat exchanger 6. After the indoor temperature is reduced and dehumidified, it flows into the gas-liquid separator 14 through the sixth solenoid valve 18 and returns to the compressor 1. The full-pass throttle valve in this mode is in a full-pass or partial throttle state depending on the outlet temperature of the indoor secondary heat exchanger 7.

[0076] The dehumidification and battery direct cooling mode of a battery direct cooling and direct heating CO2 vehicle thermal management system according to an embodiment of the present invention is as follows: the state of the valve components is consistent with the dehumidification and battery direct heating mode, and the throttling degree of the third two-way full-pass throttle valve 8 is increased, so that the subsequent CO 2 The temperature is lowered to achieve the purpose of direct cooling.

[0077] A control method of a battery direct cooling and direct heating CO2 vehicle thermal management system according to an embodiment of the present invention, a control method of a thermal management system in a dehumidification and defogging and battery direct heating mode and a dehumidification and defogging and battery direct cooling mode is as follows:

[0078] Note that the working medium temperature at one end of the main heat exchanger close to the first two-way full-pass throttle valve 4 is T6, then the control methods are: compressor 1 establishes a PID adjustment relationship with T3, T3 is the target quantity, and the compressor speed is the control quantity; the third two-way full-pass throttle valve 8 establishes a PID adjustment relationship with temperature T2, T2 is the target quantity, and the opening of the third two-way full-pass throttle valve 8 is the control quantity; the second two-way full-pass throttle valve 5 establishes a PID adjustment relationship with T6, T6 is the target quantity, and the compressor exhaust pressure P is the protection quantity under this control; the first two-way full-pass throttle valve 4 maintains a full-pass state.

[0079] In an embodiment of the present invention, in the dehumidification and demisting and battery direct heating mode control, the T2 value acquisition method is consistent with the value of the passenger compartment heating and battery direct heating mode control method; in the dehumidification and demisting and battery direct cooling mode control, the T2 value acquisition method is consistent with the value of the passenger compartment heating and battery direct cooling mode control method.

[0080] In the control of the dehumidification, demisting and battery direct heating mode and the dehumidification, demisting and battery direct cooling mode of a battery direct cooling and direct heating CO2 vehicle thermal management system in an embodiment of the present invention, when the exhaust pressure P is less than 12MPa, the value of T6 is 0; when the exhaust pressure P is greater than or equal to 12MPa, the PID control logic relationship between the second two-way full-pass throttle valve 5 and T6 is disconnected, and the second two-way full-pass throttle valve 5 is changed to establish a control relationship with the exhaust pressure, and the exhaust pressure value is always maintained at 12MPa.

[0081] As an example, the battery of the embodiment of the present invention is directly cooled and heated by CO 2 The vehicle thermal management system also includes:

[0082] The second damper is used to be arranged at the inlet of the second heat exchange channel of the indoor secondary heat exchanger 7.

[0083] A first temperature sensor, used to obtain the temperature of the vehicle battery;

[0084] The second temperature sensor is used to obtain the working medium temperature at the outlet of the direct cooling and direct heating heat exchange cold plate 9;

[0085] A third temperature sensor is used to obtain the air outlet temperature of the return air outlet;

[0086] a fourth temperature sensor, used to obtain the working medium temperature at one end of the first heat exchange channel of the indoor main heat exchanger 6;

[0087] a fifth temperature sensor, used for acquiring the working medium temperature at a preset end of the first heat exchange channel of the indoor secondary heat exchanger 7;

[0088] The sixth temperature sensor is used to obtain the working medium temperature at the other end of the first heat exchange channel of the indoor main heat exchanger 6.

[0089] The present invention can also realize separate direct cooling thermal management of the battery and direct heating thermal management of the battery for battery temperature management control during fast charging and starting processes through the combined opening and closing of valve components, all of which are within the scope of protection of this patent.

[0090] In summary, the embodiment of the present invention discloses a new energy vehicle transcritical CO2 2 A thermal management system and control method, the system comprising: a first two-way full-pass throttle valve, a direct cooling and direct heating heat exchange cold plate, a third two-way full-pass throttle valve, and an indoor secondary heat exchanger are connected in series to form a parallel structure with a second two-way throttle valve and a main heat exchanger in series; by controlling CO 2 The direct cooling of the passenger compartment and the direct cooling of the battery are controlled by the outlet dryness of the secondary heat exchanger and the inlet temperature of the direct cooling and direct heating heat exchange cold plate; the heating of the passenger compartment and the direct cooling / direct heating of the battery are controlled by the control of the third two-way full-pass throttle valve; and the large series system structure with different dehumidification amounts is realized by the combination of solenoid valves. The present invention avoids the problems of difficult control of flow rate, difficult control of dryness of the battery heat exchange cold plate outlet, easy dry burning, and uneven heating of the battery caused by large temperature glide of supercritical CO2 direct heating in the battery direct cooling and direct heating system through system layout and reasonable control method, and greatly expands the CO 2 Direct cooling and direct heating technology application.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A control method for a battery direct cooling and direct heating CO2 vehicle thermal management system, characterized in that: The battery direct cooling and direct heating CO2 vehicle thermal management system comprises: a compressor (1), an outdoor heat exchanger (2), a heat regenerator (3), a direct cooling and direct heating heat exchange cold plate (9), a gas-liquid separator (14), an HVAC module (16), an indoor fan (19), an outdoor fan (20), a first connecting pipe, a second connecting pipe and a third connecting pipe; wherein the HVAC module (16) comprises: an air duct, an indoor main heat exchanger (6) and an indoor secondary heat exchanger (7); the air duct is provided with an air inlet and an air return port, the air inlet is provided with the indoor fan (19), and the return port is provided with a A damper is provided; the outlet of the compressor (1) is connected to the inlet of the first heat exchange channel of the regenerator (3) via the first solenoid valve (10) and the first heat exchange channel of the outdoor heat exchanger (2); the outlet of the first heat exchange channel of the regenerator (3) is divided into two paths, one of which is connected to the inlet of the compressor (1) via the first two-way full-through throttle valve (4), the first heat exchange channel of the indoor main heat exchanger (6), the sixth solenoid valve (18), the gas-liquid separator (14) and the second heat exchange channel of the regenerator (3); the other of which is connected to the inlet of the compressor (1) via the second two-way full-through throttle valve (5), the direct cooling and direct heating heat exchange cold plate (9 ), a third two-way full-pass throttle valve (8), the first heat exchange channel of the indoor secondary heat exchanger (7) and the second solenoid valve (11) are connected to the outlet of the compressor (1); the outdoor fan (20) is arranged at the inlet or outlet of the second heat exchange channel of the outdoor heat exchanger (2); a fifth solenoid valve (17) is arranged on the first connecting pipe, one end of the first connecting pipe is connected to the connecting pipe between the second solenoid valve (11) and the first heat exchange channel of the indoor secondary heat exchanger (7), and the other end is connected to the connecting pipe between the sixth solenoid valve (18) and the first heat exchange channel of the indoor main heat exchanger (6). The second communicating pipe is connected to the outdoor heat exchanger (2); a fourth solenoid valve (13) is provided on the second communicating pipe, one end of the second communicating pipe is connected to the communicating pipe between the sixth solenoid valve (18) and the gas-liquid separator (14), and the other end is connected to the communicating pipe between the second solenoid valve (11) and the first communicating pipe; a third solenoid valve (12) is provided on the third communicating pipe, one end of the third communicating pipe is connected to the communicating pipe between the first solenoid valve (10) and the outdoor heat exchanger (2), and the other end is connected to the communicating pipe between the fourth solenoid valve (13) and the gas-liquid separator (14); When the passenger compartment is cooled and the battery is in direct cooling mode: the first solenoid valve (10), the fourth solenoid valve (13), and the fifth solenoid valve (17) are opened, and the second solenoid valve (11), the third solenoid valve (12), and the sixth solenoid valve (18) are closed; the CO2 working medium is compressed to a high-pressure and high-temperature state by the compressor (1), flows through the outdoor heat exchanger (2) and the regenerator (3) in sequence, and is then divided into two paths, one of which is throttled to the evaporation temperature by the first two-way full-pass throttle valve (4) and enters the indoor main heat exchanger (6 ) to cool the passenger compartment; the other path is first throttled to a preset intermediate temperature through a second two-way full-pass throttle valve (5), enters a direct cooling and direct heating heat exchange cold plate (9) to cool the battery, and then throttled to the same evaporation temperature as that in the indoor main heat exchanger (6) through a third two-way full-pass throttle valve (8), and flows into the indoor secondary heat exchanger (7) to cool the passenger compartment; the two paths are combined and then return to the compressor (1) through a fourth solenoid valve (13), a gas-liquid separator (14) and a regenerator (3); The control method in the passenger compartment cooling and battery direct cooling mode comprises the following steps: the outlet two-phase CO2 temperature of the direct cooling and direct heating heat exchange cold plate (9) is set to T2, the battery temperature is set to T1, the air outlet temperature of the return air outlet of the passenger compartment HVAC module (16) is set to T3, the working fluid temperature at one end of the indoor main heat exchanger (6) close to the first two-way full-pass throttle valve (4) is set to T6, the working fluid temperature at the other end is set to T4, and the exhaust pressure of the compressor (1) is set to P; a PID adjustment relationship is established between the compressor (1) and T3, T3 is the target quantity, and the compressor speed is the control quantity; the second two-way full A PID regulating relationship is established between the throttle valve (5) and T2, T2 is the target variable, and the opening of the second two-way full-pass throttle valve (5) is the control variable; a PID regulating relationship is established between the first two-way full-pass throttle valve (4) and the superheat of T4, the superheat is the target variable, the opening of the first two-way full-pass throttle valve (4) is the control variable, and the outlet superheat of the indoor main heat exchanger (6) is always ensured to be 1; a PID regulating relationship is established between the third two-way full-pass throttle valve (8) and the compressor exhaust pressure P, P is the target variable, and the opening of the third two-way full-pass throttle valve (8) is the control variable; In the passenger compartment heating and battery direct heating or direct cooling mode: the first solenoid valve (10), the fourth solenoid valve (13), and the fifth solenoid valve (17) are closed, and the second solenoid valve (11), the third solenoid valve (12), and the sixth solenoid valve (18) are opened; the CO2 working fluid is compressed to a high-pressure and high-temperature state by the compressor (1), and is divided into two paths after passing through the second solenoid valve (11), one path flows into the indoor main heat exchanger (6) through the fifth solenoid valve (17) to heat the passenger compartment, and the other path first flows into the indoor secondary heat exchanger (7) to heat the passenger compartment, and then enters the battery direct cooling and direct heating heat exchange plate (9) through the third two-way full-pass throttle valve (8) to heat or cool the battery; the two paths of working fluid are throttled and cooled through the first two-way full-pass throttle valve (4) and the second two-way full-pass throttle valve (5) respectively, and flow into the outdoor heat exchanger (2), and after absorbing the heat of the air, return to the compressor (1) through the third solenoid valve (12), the gas-liquid separator (14) and the regenerator (3); The control method in the passenger compartment heating and battery direct heating or direct cooling mode comprises the following steps: the working medium temperature after the third two-way full-pass throttle valve (8) is recorded as T2, the outlet temperature of the indoor secondary heat exchanger (7) is recorded as T5, the battery temperature is recorded as T1, the air outlet temperature of the return air outlet of the HVAC module (16) in the passenger compartment is recorded as T3, and the exhaust pressure of the compressor (1) is recorded as P; the compressor (1) establishes a PID adjustment relationship with T3, T3 is a target quantity, and the compressor speed is a control quantity; the third two-way full-pass throttle valve (8) establishes a PID adjustment relationship with T2, T2 is a target quantity, and the opening of the third two-way full-pass throttle valve (8) is a control quantity; the first two-way full-pass throttle valve (4) establishes a PID adjustment relationship with the exhaust pressure P, P is a target quantity, and the opening of the first two-way full-pass throttle valve (4) is a control quantity; the second two-way full-pass throttle valve (5) establishes a PID adjustment relationship with the battery temperature T1, T1 is a target quantity, and the opening of the second two-way full-pass throttle valve (5) is a control quantity.

2. The control method of a battery direct cooling and direct heating CO2 vehicle thermal management system according to claim 1 is characterized in that: In passenger compartment cooling and battery direct cooling mode, the value of T2 is related to the ambient temperature and battery temperature T1; If the battery temperature T1≤a℃ and the ambient temperature≤b℃, then T2=(20-T1+a)℃; If the battery temperature T1 ≤ a℃ and the ambient temperature is greater than b℃, the value of T2 is 20℃; If the battery temperature a℃<T1≤(a+10)℃, then T2=15℃; If the battery temperature is (a+10)℃<T1≤(a+15)℃, then the value of T2 is 10℃; If the battery temperature T1 is greater than (a+15)°C, the first two-way full-pass throttle valve (4) and the indoor fan (19) are closed, the compressor (1) runs at the maximum speed, and the second two-way full-pass throttle valve (5) changes from controlling the temperature of T2 to controlling the exhaust pressure to 12 MPa.

3. The control method of a battery direct cooling and direct heating CO2 vehicle thermal management system according to claim 1 is characterized in that: When the passenger compartment is heated and the battery is directly heated or cooled, the value of T2 is related to the ambient temperature and the battery temperature T1; If the battery temperature T1≤a℃, then T2=(20-T1+a)℃; If the battery temperature a℃<T1≤(a+10)℃, then T2=15℃; If the battery temperature is (a+10)℃<T1≤(a+15)℃, then the value of T2 is 10℃; If the battery temperature T1>(a+15)°C, the first two-way full-pass throttle valve (4) and the indoor fan (19) are closed, and the second two-way full-pass throttle valve (5) is in a full-pass state, the compressor (1) runs at the maximum speed, and the third two-way full-pass throttle valve (8) controls the temperature of T2 and changes to control the exhaust pressure to 12MPa; In the passenger compartment heating and battery direct heating mode, when T5 is less than 60°C, the third two-way full-pass throttle valve (8) is in a fully open state; when T5 is greater than or equal to 60°C, the value of T2 is 55°C.

4. The control method of a battery direct cooling and direct heating CO2 vehicle thermal management system according to claim 1 is characterized in that: The dehumidification and battery direct heating or direct heating mode of the battery direct cooling and direct heating CO2 vehicle thermal management system includes: When the ambient temperature is less than or equal to 10°C and dehumidification and defogging are performed, the second solenoid valve (11), the third solenoid valve (12), and the sixth solenoid valve (18) are opened, and the first solenoid valve (10), the fourth solenoid valve (13), and the fifth solenoid valve (17) are closed; the CO2 working medium is compressed to a high-pressure and high-temperature state by the compressor (1), and flows through the second solenoid valve (11), the indoor secondary heat exchanger (7), the third two-way full-pass throttle valve (8), the battery direct cooling and direct heating heat exchange plate (9), and the second two-way full-pass throttle valve (5) in sequence, and then is divided into two paths, one of which flows into the outdoor heat exchanger (2) to absorb ambient heat, and the other flows into the indoor main heat exchanger (6) through the first two-way full-pass throttle valve (4). The first two-way full-pass throttle valve (4) is in a fully open state. After the indoor temperature is reduced and dehumidified, it flows into the gas-liquid separator (14) through the sixth solenoid valve (18), and merges with the other working medium in the gas-liquid separator through the third solenoid valve (12) and returns to the compressor (1); When the ambient temperature is greater than 10°C and dehumidification and defogging are performed, the second solenoid valve (11) and the sixth solenoid valve (18) are opened, and the first solenoid valve (10), the third solenoid valve (12), the fourth solenoid valve (13), and the fifth solenoid valve (17) are closed; the CO2 working fluid is compressed to a high-pressure and high-temperature state by the compressor (1), and flows in sequence through the second solenoid valve (11), the indoor secondary heat exchanger (7), the third two-way full-pass throttle valve (8), the battery direct cooling and direct heating heat exchange plate (9), the second two-way full-pass throttle valve (5), and the first two-way full-pass throttle valve (4) into the indoor main heat exchanger (6), and after the indoor temperature is reduced and dehumidified, it flows into the gas-liquid separator (14) through the sixth solenoid valve (18) and returns to the compressor (1).

5. The control method of a battery direct cooling and direct heating CO2 vehicle thermal management system according to claim 4 is characterized in that: The control method in dehumidification and battery direct heating or direct heating mode includes the following steps: The working medium temperature after the third two-way full-pass throttle valve (8) is T2, the working medium temperature at one end of the indoor main heat exchanger (6) close to the first two-way full-pass throttle valve (4) is T6, the air outlet temperature of the return air outlet of the HVAC module (16) in the passenger compartment is T3, and the exhaust pressure of the compressor (1) is P; A PID regulation relationship is established between compressor (1) and T3, where T3 is the target quantity and the compressor speed is the control quantity; A PID regulating relationship is established between the third two-way full-pass throttle valve (8) and the temperature T2, wherein T2 is the target value and the opening degree of the third two-way full-pass throttle valve (8) is the control value; The second two-way full-pass throttle valve (5) establishes a PID regulation relationship with T6, T6 is the target value, and the compressor exhaust pressure P is the protection value under this control; the first two-way full-pass throttle valve (4) maintains a full-pass state.

6. The control method of a battery direct cooling and direct heating CO2 vehicle thermal management system according to claim 5 is characterized in that: In the control method of dehumidification and battery direct heating or direct heating mode, When the exhaust pressure P is less than 12MPa, the value of T6 is 0; When the exhaust pressure P≥12MPa, the PID control logic relationship between the second two-way full-pass throttle valve (5) and T6 is disconnected, and the second two-way full-pass throttle valve (5) is changed to establish a control relationship with the exhaust pressure, and the exhaust pressure value is always maintained at 12MPa.

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