A frost-free heat pump system and thermal management method for hydrogen-powered vehicles without a PTC heater

Abstract

The present invention provides a frost-free heat pump system and thermal management method for hydrogen-powered vehicles without a PTC heater. The system comprises a battery pack thermal management circulation system, comprising a battery pack, an evaporator, and a condenser, all fluidically connected end-to-end to form a battery pack thermal management circulation loop. A bypass line is provided in parallel with the battery pack. A passenger compartment thermal management circulation system comprises a compressor, an outdoor heat exchanger, an indoor heat exchanger, and an electronic expansion valve for both heating and cooling circuits. The electronic expansion valve is located between the outdoor and indoor heat exchangers in the cooling circuit, and the heating electronic expansion valve is located between the indoor and outdoor heat exchangers in the heating circuit. The present invention utilizes a circulating medium to utilize the heat from the high-speed operation of the compressor as the primary heat source for the heat pump under low-temperature operating conditions. This resolves the heat pump frosting problem without adding a PTC heater. The system also integrates the thermal management systems of the battery pack and passenger compartment, making the heat pump system more efficient, energy-efficient, and economical.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen-powered automobile air conditioning, and in particular to a non-frost heat pump system for a hydrogen-powered automobile without a PTC heater and a thermal management method. Background Art

[0002] At present, when air-source heat pump systems are used for heating in winter, there is a common problem of frost on the surface of the outdoor heat exchanger, which requires defrosting. During the defrosting process, it is easy to cause fluctuations in the comfort level in the vehicle. At this time, the refrigerant often needs to flow in reverse or bypass, or PTC needs to be added for auxiliary heating.

[0003] In addition, during the heating process under low-temperature conditions, the compressor is limited by the low suction superheat and cannot run at full speed and provide more heat to the system, resulting in insufficient heating in low-temperature environments. It can neither absorb heat from the air nor generate heat itself, and needs to rely entirely on PTC heating for heating.

[0004] The passenger compartment heat pump air-conditioning systems of pure electric vehicles on the market are generally integrated with the battery thermal management system. The battery thermal management system is also responsible for heating or cooling the battery circuit. When selecting the compressor, it is necessary to take into account the needs of both the battery pack and the passenger compartment. When the compressor runs at full speed, the heat output available for development and utilization can actually reach 5-6kW, which is not inferior to the heat output of a high-voltage PTC. Summary of the Invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a frost-free heat pump system and thermal management method for a hydrogen-powered vehicle without a PTC heater, so as to solve the technical problem that traditional air-source heat pumps cannot absorb heat from the ambient air under low-temperature conditions and are prone to frost.

[0006] To solve the above problems, the present invention provides a frost-free heat pump system for hydrogen-powered vehicles without a PTC heater, comprising:

[0007] A battery pack thermal management circulation system, comprising a battery pack, a first inlet of an evaporator, a first outlet of the evaporator, a first inlet of a condenser, and a first outlet of the condenser, which are fluidically connected end to end to form a battery pack thermal management circulation loop, wherein a bypass line is provided in parallel with the battery pack; and a water pump is provided in the battery pack thermal management circulation loop;

[0008] A passenger compartment thermal management cycle system includes a compressor, an outdoor heat exchanger, an indoor heat exchanger, a cooling electronic expansion valve, a heating electronic expansion valve, an evaporator electronic expansion valve, the evaporator, and the condenser, which constitute a heating cycle and a cooling cycle. The cooling electronic expansion valve is arranged between the outdoor heat exchanger and the indoor heat exchanger in the cooling cycle; the heating electronic expansion valve is arranged between the indoor heat exchanger and the outdoor heat exchanger in the heating cycle.

[0009] The evaporator electronic expansion valve is provided between the second outlet of the condenser and the second inlet of the evaporator;

[0010] The outlet of the compressor is selectively fluidly connected to the inlet of the outdoor heat exchanger, the inlet of the indoor heat exchanger, and the second inlet of the condenser;

[0011] The inlet of the compressor is selectively fluidly connected to the second outlet of the evaporator, the outlet of the outdoor heat exchanger, and the outlet of the indoor heat exchanger;

[0012] The outlet of the indoor heat exchanger is selectively fluidly connected to the inlet of the outdoor heat exchanger, the second inlet of the condenser, and the second inlet of the evaporator;

[0013] The inlet of the indoor heat exchanger is selectively fluidly connected to the outlet of the outdoor heat exchanger and the second outlet of the condenser;

[0014] The inlet of the outdoor heat exchanger is fluidly connected to the second outlet of the condenser;

[0015] The outlet of the outdoor heat exchanger is fluidly connected to the second inlet of the evaporator.

[0016] Optionally, the refrigeration cycle includes the compressor, the first refrigeration solenoid valve, the outdoor heat exchanger, the refrigeration electronic expansion valve, the indoor heat exchanger, the second refrigeration solenoid valve and the gas-liquid separator connected in end to end;

[0017] The heating cycle includes the compressor, the first heating solenoid valve, the indoor heat exchanger, the heating electronic expansion valve, the outdoor heat exchanger, the second heating solenoid valve and the gas-liquid separator connected in end to end; and / or,

[0018] The outer surface of the compressor is completely covered with a thermal insulation layer.

[0019] Optionally, a condenser solenoid valve is provided between the compressor and the second inlet of the condenser; the condenser and the evaporator are connected in series to form a first parallel branch, and the first parallel branch is connected in series with the gas-liquid separator and the compressor.

[0020] Optionally, it also includes: a first evaporation solenoid valve, an evaporator solenoid valve, the condenser, the evaporator electronic expansion valve, and the evaporator are fluidly connected in sequence to form a second parallel branch, the second parallel branch is located after the indoor heat exchanger in the heating cycle, and is arranged in series with the pipeline between the gas-liquid separator, and the outlet of the gas-liquid separator is fluidly connected to the inlet of the compressor.

[0021] Optionally, the invention further comprises a third parallel branch formed by fluidly connecting a second evaporation solenoid valve, a battery pack solenoid valve, the evaporator electronic expansion valve, and the evaporator in sequence, wherein the third parallel branch is connected in series with a pipeline located after the outdoor heat exchanger and between the gas-liquid separator in the refrigeration cycle, and the outlet of the gas-liquid separator is fluidly connected to the inlet of the compressor; and / or,

[0022] It also includes a first three-way valve, wherein the first three-way valve replaces the first cooling solenoid valve and the first heating solenoid valve; or

[0023] It also includes a second three-way valve, which replaces the second heating solenoid valve; or

[0024] It also includes a third three-way valve, which replaces the second evaporation solenoid valve; or

[0025] The bypass line and the input end of the battery pack are respectively provided with a solenoid valve, or the input end of the battery pack is provided with a fourth three-way valve, and the third outlet of the fourth three-way valve is fluidically connected to the bypass line.

[0026] The present invention also provides a thermal management method, which is applied to the above-mentioned hydrogen-powered vehicle frost-free heat pump system without a PTC heater. The thermal management method comprises the following steps:

[0027] S1: Acquire a passenger compartment thermal management mode; wherein the passenger compartment thermal management mode includes a passenger compartment heating mode, a passenger compartment cooling mode, and a passenger compartment no-demand mode;

[0028] S2: Obtaining a battery pack thermal management mode; wherein the battery pack thermal management mode includes a battery pack no-demand mode, a battery pack average temperature mode, a battery pack heating mode, and a battery pack cooling mode;

[0029] S3: Control the on-off status of the pipelines formed by the compressor, outdoor heat exchanger, indoor heat exchanger, cooling electronic expansion valve, heating electronic expansion valve, battery pack, evaporator and condenser, and evaporator electronic expansion valve, as well as their respective operating states, so that the operation of the hydrogen-powered automobile heat pump system based on the PTC-free heater circulating water circuit meets the passenger compartment thermal management mode and the battery pack thermal management mode.

[0030] Optionally, when the passenger compartment thermal management mode is the passenger compartment heating mode and the battery pack thermal management mode is the battery pack temperature equalization mode, step S3 specifically includes the following steps:

[0031] S301: Control a portion of the high-temperature and high-pressure working fluid from the compressor to flow through the indoor heat exchanger for cooling to form a sub-high-temperature and high-pressure working fluid and thereby increase the temperature of the passenger compartment; the remaining portion of the high-temperature and high-pressure working fluid from the compressor flows through the condenser for cooling to form a sub-high-temperature and high-pressure working fluid; the sub-high-temperature and high-pressure working fluid flowing out of the indoor heat exchanger is divided into two branches, the sub-high-temperature and high-pressure working fluid from one branch flows to the heating electronic expansion valve, is throttled and reduced in pressure to form a low-temperature and low-pressure working fluid, then flows to the outdoor heat exchanger to cool the ambient air to a temperature not lower than its dew point temperature, and is heated to form a sub-low-temperature and low-pressure working fluid before flowing to the compressor; the sub-high-temperature and high-pressure working fluid from the other branch is mixed with the sub-high-temperature and high-pressure working fluid cooled by the condenser through the first evaporator solenoid valve and the battery pack solenoid valve, then flows to the evaporator electronic expansion valve, is throttled and reduced in pressure, then flows to the evaporator for heating to form a low-temperature and low-pressure working fluid, and then flows to the compressor; control the working fluid in the battery pack thermal management circulation loop to flow through the battery pack, the evaporator, and the condenser in sequence under the action of the water pump;

[0032] S302: regulating the opening of the heating electronic expansion valve according to the ambient air being cooled to a temperature not lower than its dew point temperature and the superheat of the low-temperature and low-pressure working fluid exiting the outdoor heat exchanger;

[0033] S303: regulating the speed of the compressor according to the required heating amount of the passenger cabin heating mode and the heat provided by the ambient air;

[0034] S304: regulating the flow rate of the sub-high temperature and high pressure working fluid flowing to the evaporator and the opening of the evaporator electronic expansion valve according to the opening of the heating electronic expansion valve and the speed of the compressor;

[0035] S305: Regulating the flow rate of the high-temperature and high-pressure working medium from the compressor to the condenser according to the superheat of the sub-low-temperature and low-pressure working medium discharged from the evaporator and the water inlet temperature of the battery pack.

[0036] Optionally, when the passenger compartment thermal management mode is a passenger compartment heating mode and the battery pack thermal management mode is a battery pack heating mode, step S3 specifically includes the following steps:

[0037] S306: Control a portion of the high-temperature and high-pressure working fluid from the compressor to flow through the indoor heat exchanger for cooling to form a sub-high-temperature and high-pressure working fluid, and then flow to the heating electronic expansion valve after heating the passenger compartment, where it is throttled and depressurized to form a low-temperature and low-pressure working fluid, and then flow to the outdoor heat exchanger to cool the ambient air to no less than its dew point temperature, and then heat it up to form a sub-low-temperature and low-pressure working fluid, and then flow to the compressor; the remaining portion of the high-temperature and high-pressure working fluid from the compressor flows through the condenser for cooling to form a sub-high-temperature and high-pressure working fluid, and then flows to the evaporator electronic expansion valve, where it is throttled and depressurized, and then flows to the evaporator for heating to form a sub-low-temperature and low-pressure working fluid, and then flows to the compressor; control the working fluid in the battery pack thermal management circulation loop to flow through the battery pack, the evaporator, and the condenser in sequence under the action of the water pump;

[0038] S307: regulating the opening of the heating electronic expansion valve according to the ambient air being cooled to a temperature not lower than its dew point temperature and the superheat of the low-temperature, low-pressure working fluid exiting the outdoor heat exchanger;

[0039] S308: regulating the speed of the compressor according to the required heating amount of the heating demand and the heat provided by the ambient air;

[0040] S309: regulating the flow rate of the sub-high temperature and high pressure working fluid flowing to the evaporator and the opening of the evaporator electronic expansion valve according to the opening of the heating electronic expansion valve and the speed of the compressor;

[0041] S310: Regulating the flow of the high-temperature and high-pressure working medium to the condenser according to the superheat of the sub-low-temperature and low-pressure working medium discharged from the evaporator and the water inlet temperature of the battery pack;

[0042] and / or,

[0043] When the passenger compartment thermal management mode is the passenger compartment heating mode and the battery pack thermal management mode is the battery pack cooling mode, step S3 specifically includes the following steps:

[0044] S311: Controlling the high-temperature and high-pressure working fluid from the compressor to flow through the indoor heat exchanger for cooling to form a sub-high-temperature and high-pressure working fluid and thereby heating the passenger compartment; a portion of the sub-high-temperature and high-pressure working fluid flows to the heating electronic expansion valve, is throttled and depressurized to form a low-temperature and low-pressure working fluid, and then flows to the outdoor heat exchanger to cool the ambient air to a temperature not lower than its dew point temperature, and then heats it to form a sub-low-temperature and low-pressure working fluid and then flows to the compressor; the remaining portion of the sub-high-temperature and high-pressure working fluid flows to the evaporator electronic expansion valve for throttling and depressurization, then flows to the evaporator for heating to form a sub-low-temperature and low-pressure working fluid and then flows to the compressor; controlling the working fluid in the battery pack thermal management circulation loop to flow sequentially through the battery pack, the condenser, and the evaporator under the action of the water pump;

[0045] S312: regulating the opening of the heating electronic expansion valve according to the ambient air being cooled to a temperature not lower than its dew point temperature and the superheat of the low-temperature and low-pressure working fluid output from the outdoor heat exchanger;

[0046] S313: regulating the speed of the compressor according to the required heating amount of the heating demand and the heat provided by the ambient air;

[0047] S314: regulating the flow rate of the sub-high temperature and high pressure working fluid flowing to the evaporator and the opening of the evaporator electronic expansion valve according to the opening of the heating electronic expansion valve and the speed of the compressor;

[0048] and / or,

[0049] When the passenger compartment thermal management mode is the passenger compartment cooling mode and the battery pack thermal management mode is the battery pack cooling mode, step S3 specifically includes the following steps:

[0050] S315: Controlling the high-temperature and high-pressure working fluid from the compressor to flow through the outdoor heat exchanger for cooling to form a sub-high-temperature and high-pressure working fluid; a portion of the sub-high-temperature and high-pressure working fluid flows to the refrigeration electronic expansion valve, is throttled and depressurized to form a low-temperature and low-pressure working fluid, and then flows to the indoor heat exchanger for heating to form a sub-low-temperature and low-pressure working fluid to cool the passenger compartment, and then flows to the compressor; the remaining portion of the sub-high-temperature and high-pressure working fluid flows to the evaporator electronic expansion valve, is throttled and depressurized, and then flows to the evaporator for heating to form a sub-low-temperature and low-pressure working fluid, and then flows to the compressor; controlling the working fluid in the battery pack thermal management circulation loop to flow through the battery pack, the evaporator, the condenser, etc. in sequence under the action of the water pump;

[0051] S316: regulating the speed of the compressor, the opening of the refrigeration electronic expansion valve, and the opening of the evaporator electronic expansion valve according to the required cooling capacity of the refrigeration demand and the required heat dissipation of the battery pack;

[0052] and / or,

[0053] When the passenger compartment thermal management mode is the passenger compartment cooling mode and the battery pack thermal management mode is the battery pack heating mode, step S3 specifically includes the following steps:

[0054] S317: Controlling the high-temperature and high-pressure working fluid from the compressor to flow to the condenser for cooling to form a sub-high-temperature and high-pressure working fluid. A portion of the sub-high-temperature and high-pressure working fluid flows to the refrigeration electronic expansion valve, is throttled and depressurized to form a low-temperature and low-pressure working fluid, and then flows to the indoor heat exchanger for heating to form a sub-low-temperature and low-pressure working fluid to cool the passenger compartment, and then flows to the compressor. The remaining portion of the sub-high-temperature and high-pressure working fluid flows to the evaporator electronic expansion valve, is throttled and depressurized, and then flows to the evaporator for heating to form a sub-low-temperature and low-pressure working fluid, and then flows to the compressor. Controlling the working fluid in the battery pack thermal management circulation loop to flow through the battery pack, the evaporator, and the condenser in sequence under the action of the water pump.

[0055] S318: regulating the speed of the compressor, the opening of the refrigeration electronic expansion valve, and the opening of the evaporator electronic expansion valve according to the required cooling capacity of the refrigeration demand and the required heating capacity of the battery pack;

[0056] and / or,

[0057] When the passenger compartment thermal management mode is the passenger compartment cooling mode and the battery pack thermal management mode is the battery pack temperature equalization mode, step S3 specifically includes the following steps:

[0058] S319: Controlling the high-temperature and high-pressure working fluid from the compressor to flow through the outdoor heat exchanger for cooling to form a sub-high-temperature and high-pressure working fluid, then flowing to the refrigeration electronic expansion valve for throttling and pressure reduction to form a low-temperature and low-pressure working fluid, then flowing to the indoor heat exchanger for heating to form a sub-low-temperature and low-pressure working fluid to cool the passenger compartment, and then flowing to the compressor; controlling the working fluid in the battery pack thermal management circulation loop to flow through the battery pack, the evaporator, and the condenser in sequence under the action of the water pump;

[0059] S320: regulating the speed of the compressor according to the required cooling capacity of the cooling demand;

[0060] S321: regulating the opening of the refrigeration electronic expansion valve according to the superheat of the sub-low temperature and low pressure working medium output from the indoor heat exchanger;

[0061] and / or,

[0062] When the passenger compartment thermal management mode is the passenger compartment cooling mode and the battery pack thermal management mode is the battery pack no-demand mode, step S3 specifically includes the following steps:

[0063] S322: Controlling the high-temperature and high-pressure working fluid from the compressor to flow through the outdoor heat exchanger to reduce its temperature to form a secondary high-temperature and high-pressure working fluid, then flowing to the refrigeration electronic expansion valve to be throttled and reduced in pressure to form a low-temperature and low-pressure working fluid, then flowing to the indoor heat exchanger to increase its temperature to form a secondary low-temperature and low-pressure working fluid to cool the passenger compartment, and then flowing to the compressor;

[0064] S323: regulating the speed of the compressor according to the required cooling capacity of the passenger compartment cooling mode;

[0065] S324: regulating the opening of the refrigeration electronic expansion valve according to the superheat of the sub-low temperature and low pressure working medium output from the indoor heat exchanger;

[0066] and / or,

[0067] When the passenger compartment thermal management mode is the passenger compartment no-demand mode and the battery pack thermal management mode is the battery pack uniform temperature mode, step S3 specifically includes the following steps:

[0068] S325: Controlling the working fluid of the battery pack thermal management circulation loop to flow sequentially through the battery pack, the condenser, and the evaporator under the action of the water pump;

[0069] and / or,

[0070] When the passenger compartment thermal management mode is the passenger compartment no-demand mode and the battery pack thermal management mode is the battery pack heating mode, step S3 specifically includes the following steps:

[0071] S326: Controlling the high-temperature and high-pressure working fluid from the compressor to flow through the condenser to be cooled to form a sub-high-temperature and high-pressure working fluid, a portion of which flows to the heating electronic expansion valve, is throttled and reduced in pressure to form a low-temperature and low-pressure working fluid, and then flows to the outdoor heat exchanger to cool the ambient air to a temperature not lower than its dew point temperature, and then heats it to form a sub-low-temperature and low-pressure working fluid, and then flows to the compressor, and the remaining portion of the sub-high-temperature and high-pressure working fluid flows to the evaporator electronic expansion valve, is throttled and reduced in pressure, and then flows to the evaporator to be heated to form a sub-low-temperature and low-pressure working fluid, and then flows to the compressor; controlling the working fluid in the battery pack thermal management circulation loop to flow through the battery pack, the evaporator, and the condenser in sequence under the action of the water pump;

[0072] S327: Regulating the speed of the compressor, the opening of the heating electronic expansion valve, and the opening of the evaporator electronic expansion valve according to the ambient air being cooled to a temperature not lower than its dew point temperature and the required heating amount of the battery pack;

[0073] and / or,

[0074] When the passenger compartment thermal management mode is the passenger compartment no-demand mode and the battery pack thermal management mode is the battery pack cooling mode, step S3 specifically includes the following steps:

[0075] S328: Controlling the high-temperature and high-pressure working fluid from the compressor to flow through the outdoor heat exchanger to reduce its temperature to form a secondary high-temperature and high-pressure working fluid, then flowing to the evaporator electronic expansion valve to be throttled and reduced in pressure to form a low-temperature and low-pressure working fluid, then flowing to the evaporator to be heated to form a secondary low-temperature and low-pressure working fluid, and then flowing to the compressor; controlling the working fluid in the battery pack thermal management circulation loop to flow through the battery pack, the evaporator, and the condenser in sequence under the action of the water pump;

[0076] S329: regulating the speed of the compressor according to the required cooling capacity of the battery pack;

[0077] S330: Regulating the opening of the electronic expansion valve of the evaporator according to the superheat of the sub-high temperature and high pressure working fluid output from the evaporator.

[0078] Optionally, when the passenger compartment thermal management mode is the passenger compartment heating mode and the battery pack thermal management mode is the battery pack no-demand mode, step S3 specifically includes the following steps:

[0079] S331: Controlling the high-temperature and high-pressure working fluid from the compressor to flow through the indoor heat exchanger for cooling to form a sub-high-temperature and high-pressure working fluid and thereby heating the passenger compartment; a portion of the sub-high-temperature and high-pressure working fluid flows to the heating electronic expansion valve, is throttled and depressurized to form a low-temperature and low-pressure working fluid, and then flows to the outdoor heat exchanger to cool the ambient air to a temperature not lower than its dew point temperature, and then heats it to form a sub-low-temperature and low-pressure working fluid and then flows to the compressor; the remaining portion of the sub-high-temperature and high-pressure working fluid flows to the condenser for cooling, and then is throttled and depressurized by the evaporator electronic expansion valve, and then flows to the evaporator for heating to form a sub-low-temperature and low-pressure working fluid and then flows to the compressor; controlling the working fluid in the battery pack thermal management circulation loop to flow sequentially through the bypass pipe, the evaporator, and the condenser under the action of the water pump;

[0080] S332: regulating the opening of the heating electronic expansion valve according to the ambient air being cooled to a temperature not lower than its dew point temperature and the superheat of the low-temperature and low-pressure working fluid output from the outdoor heat exchanger;

[0081] S333: regulating the speed of the compressor according to the required heating amount for heating and the heat provided by the ambient air;

[0082] S334: Regulating the flow rate of the sub-high temperature and high pressure working fluid flowing to the evaporator and the opening of the evaporator electronic expansion valve according to the opening of the heating electronic expansion valve and the rotation speed of the compressor.

[0083] Optionally, the method further comprises the steps of:

[0084] S335: Determine whether the superheat of the working fluid discharged from the evaporator is lower than a preset value;

[0085] When the superheat of the working fluid discharged from the evaporator is lower than a preset value, the battery pack thermal management mode is switched from the battery pack no-demand mode to the battery pack uniform temperature mode, and steps S301 to S305 are executed until the water temperature of the battery pack thermal management circulation loop reaches a maximum temperature threshold of not less than the battery no-demand, the battery pack thermal management mode is switched from the battery pack uniform temperature mode to the battery pack no-demand mode, and steps S331 to S334 are executed; otherwise, the battery pack thermal management mode continues to be maintained as the battery pack uniform temperature mode and steps S301 to S305 are executed.

[0086] Compared with the prior art, the present invention has the following beneficial effects:

[0087] 1. Connecting the battery pack thermal management circulation system in parallel with the passenger compartment thermal management circulation system can prevent the battery heat from being unable to dissipate due to the small temperature difference between the water circulation and the ambient air when the battery dissipates a lot of heat. By using the circulating water system to act like a heat accumulator, the heat generated by the high-speed operation of the compressor is used as the main heat source for the heat pump under low-temperature conditions. Without adding additional components such as PTC and regenerators, this not only solves the problem of heat pump frosting, but also integrates the thermal management systems of the battery pack and passenger compartment, making the heat pump system more efficient, energy-saving, comfortable and economical.

[0088] 2. It solves the problem that traditional air source heat pumps cannot absorb heat from the ambient air under low temperature conditions and must add PTC for heating. BRIEF DESCRIPTION OF THE DRAWINGS

[0089] Figure 1 This is a schematic structural diagram of a frost-free heat pump system for a hydrogen-powered vehicle according to an embodiment of the present invention;

[0090] Figure 2 This is a schematic diagram of the system structure of the hydrogen-powered vehicle's non-frost heat pump system in an embodiment of the present invention in a passenger compartment heating mode in winter with no demand on the battery pack;

[0091] Figure 3 This is a schematic diagram of the system structure of the hydrogen-powered vehicle's frost-free heat pump system in a winter passenger compartment heating and battery pack temperature equalization mode according to an embodiment of the present invention;

[0092] Figure 4 This is a schematic diagram of the system structure of the hydrogen-powered vehicle's frost-free heat pump system in a winter passenger compartment heating and battery pack heating mode according to an embodiment of the present invention;

[0093] Figure 5 This is a schematic diagram of the system structure of the hydrogen-powered vehicle's frost-free heat pump system in a winter passenger compartment heating and battery pack cooling mode according to an embodiment of the present invention;

[0094] Figure 6This is a schematic diagram of the system structure of the hydrogen-powered vehicle's frost-free heat pump system in a summer passenger cabin cooling and battery pack cooling mode according to an embodiment of the present invention;

[0095] Figure 7 This is a schematic diagram of the system structure of the hydrogen vehicle's frost-free heat pump system in a summer passenger cabin cooling and battery pack heating mode according to an embodiment of the present invention;

[0096] Figure 8 This is a schematic diagram of the system structure of the hydrogen-powered vehicle's frost-free heat pump system in a summer passenger cabin cooling and battery pack temperature equalization mode according to an embodiment of the present invention;

[0097] Figure 9 This is a schematic diagram of the system structure of the non-frost heat pump system of a hydrogen-powered vehicle in an embodiment of the present invention in a passenger cabin cooling mode in summer and with no demand on the battery pack;

[0098] Figure 10 This is a schematic diagram of the system structure of the hydrogen vehicle's non-frost heat pump system in an embodiment of the present invention in a passenger cabin no-demand mode and a battery pack uniform temperature mode;

[0099] Figure 11 This is a schematic diagram of the system structure of the hydrogen-powered vehicle's non-frost heat pump system in the passenger compartment no-demand mode and the battery pack heating mode according to an embodiment of the present invention;

[0100] Figure 12 This is a schematic diagram of the system structure of the hydrogen vehicle's non-frost heat pump system in an embodiment of the present invention in a passenger compartment no-demand mode and a battery pack cooling mode;

[0101] Figure 13 Schematic diagram of the process of the thermal management method of the frost-free heat pump system of a hydrogen vehicle in an embodiment of the present invention.

[0102] Description of reference numerals:

[0103] 1-Compressor; 2-Outdoor heat exchanger; 3-Refrigeration electronic expansion valve; 4-Indoor heat exchanger; 5-Gas-liquid separator; 6-First refrigeration solenoid valve; 7-Second refrigeration solenoid valve; 8-Heating electronic expansion valve; 9-First heating solenoid valve; 10-Second heating solenoid valve; 11-Main air supply blower; 12-Cooling axial fan; 13-HVAC air conditioning box shell; 14-Water-cooled condenser solenoid valve; 15-Water-cooled evaporator electronic expansion valve; 16-Water-cooled evaporator solenoid valve; 17-Water-cooled condenser; 18-Water-cooled evaporator; 19-Water pump; 20-Battery pack; 21-Battery pack solenoid valve; 22-First evaporation solenoid valve; 23-Second evaporation solenoid valve; 24-Fourth three-way valve. DETAILED DESCRIPTION

[0104] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0105] In the description of the present invention, it should be noted that the terms "first", "second", etc. are used for descriptive purposes and should not be understood as indicating or implying relative importance.

[0106] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components; wireless connections or wired connections. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0107] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0108] See also Figure 1 As shown, an embodiment of the present invention provides a frost-free heat pump system for hydrogen-powered vehicles without a PTC heater, comprising: a passenger compartment thermal management circulation system and a battery pack thermal management circulation system.

[0109] Specifically in this embodiment, the battery pack thermal management circulation system includes a battery pack 20, a first inlet of the evaporator 18, a first outlet of the evaporator 18, a first inlet of the condenser 17 and a first outlet of the condenser 17, which are fluidically connected end to end to form a battery pack thermal management circulation loop, wherein the battery pack 20 is provided with a bypass line in parallel, and the battery pack thermal management circulation loop is provided with a water pump 19.

[0110] The passenger compartment thermal management cycle system includes a compressor 1, an outdoor heat exchanger 2, an indoor heat exchanger 4, a cooling electronic expansion valve 3, a heating electronic expansion valve 8, an evaporator electronic expansion valve 15, an evaporator 18 and a condenser 17, which constitute a heating cycle loop and a cooling cycle loop, wherein the cooling electronic expansion valve 3 is arranged between the outdoor heat exchanger 2 and the indoor heat exchanger 4 in the cooling cycle loop, and the heating electronic expansion valve 8 is arranged between the indoor heat exchanger 4 and the outdoor heat exchanger 2 in the heating cycle loop.

[0111] The evaporator electronic expansion valve 15 is provided between the second outlet of the condenser 17 and the second inlet of the evaporator 18 .

[0112] Specifically, see Figure 1 As shown, in an embodiment of the present invention, the outlet of the compressor 1 is selectively connected to the inlet of the outdoor heat exchanger 2, the inlet of the indoor heat exchanger 4, and the second inlet fluid of the condenser 17; the inlet of the compressor 1 is selectively connected to the second outlet of the evaporator 18, the outlet of the outdoor heat exchanger 2, and the outlet fluid of the indoor heat exchanger 4.

[0113] The outlet of the indoor heat exchanger 4 is selectively connected to the inlet of the outdoor heat exchanger 2 , the second inlet of the condenser 17 , and the second inlet of the evaporator 18 ; the inlet of the indoor heat exchanger 4 is connected to the second outlet of the condenser 17 .

[0114] The inlet of the outdoor heat exchanger 2 is fluidically connected to the second outlet of the condenser 17 ; the outlet of the outdoor heat exchanger 2 is fluidically connected to the second inlet of the evaporator 18 .

[0115] Therefore, the passenger compartment thermal management cycle system includes a heating cycle circuit and a refrigeration cycle circuit, and a plurality of automatically switching electric valves are provided in the heating cycle circuit and the refrigeration cycle circuit to realize cooling and heating of the passenger compartment.

[0116] In this embodiment of the present invention, the bypass line utilizes a fourth three-way valve 24, which has three ports. The first end of the fourth three-way valve 24 is connected to the water pump 19, the second end of the fourth three-way valve 24 is connected to the battery pack 20, and the third end of the fourth three-way valve 24 is connected to the end of the battery pack 20, remote from the fourth three-way valve 24, via a water pipe short circuit. The first inlet of the evaporator 18 is connected to the outlet of the battery pack 20, and the first outlet of the condenser 17 is connected to the water pump 19. Thus, a circulation loop formed by the battery pack 20, evaporator 18, condenser 17, water pump 19, and fourth three-way valve 24 allows the medium water to flow through the circulation loop to achieve heat exchange.

[0117] It should be noted that in this embodiment, the medium used in the battery pack thermal management circulation system is circulating water. Circulating water not only has a better heat exchange effect, but is also easy to obtain and has a low cost. Of course, it can also be replaced with other circulating cooling media to meet actual heat exchange needs.

[0118] In addition, in an embodiment of the present invention, there are two circulating medium pipelines inside the condenser 17 and the evaporator 18, that is, there are two inlets (a first inlet and a second inlet) and two outlets (a first outlet and a second outlet) connected to the two inlets in a one-to-one manner, and the first inlet and the second inlet are arranged in reverse symmetry, and the second outlet and the second outlet are arranged in reverse symmetry. The advantage of such an arrangement is that heat exchange between the two circulating medium pipelines can be better achieved.

[0119] The second inlet of condenser 17 in the battery pack thermal management system is connected to the outlet of compressor 1 of the heating circuit via condenser solenoid valve 14. The second outlet of condenser 17 is connected to the second inlet of evaporator 18 via evaporator electronic expansion valve 15. The second outlet of evaporator 18 is connected to the outlet of indoor heat exchanger 4 of the heating circuit. This connects the water circuit of the battery pack thermal management system in parallel with both the heating and cooling circuits. By activating the air conditioning system to cool the battery pack 20, the battery pack 20 does not suffer from insufficient heat dissipation.

[0120] Therefore, connecting the battery pack thermal management circulation system in parallel with the passenger compartment thermal management circulation system can avoid the situation where the heat of the battery cannot be dissipated due to the small temperature difference between the water circulation and the ambient air when the heat dissipation of the battery is large; the circulating water system plays a role similar to a heat accumulator, and the heat generated by the high-speed operation of the compressor is used as the main heat source of the heat pump under low-temperature conditions. Without adding additional components such as PTC and heat regenerators, it not only solves the problem of frosting of the heat pump, but also integrates the thermal management systems of the battery pack and the passenger compartment, making the heat pump system more efficient, energy-saving, comfortable and economical.

[0121] Specifically, see Figure 1 As shown, in an embodiment of the present invention, the refrigeration cycle loop includes a compressor 1, a first refrigeration solenoid valve 6, an outdoor heat exchanger 2, a refrigeration electronic expansion valve 3, an indoor heat exchanger 4, a second refrigeration solenoid valve 7 and a gas-liquid separator 5 connected in sequence.

[0122] The heating cycle includes a compressor 1, a first heating solenoid valve 9, an indoor heat exchanger 4, a heating electronic expansion valve 8, an outdoor heat exchanger 2, a second heating solenoid valve 10 and a gas-liquid separator 5 connected in sequence.

[0123] In another embodiment of the present invention, based on but not limited to the above embodiment, the outer surface of the compressor 1 of this embodiment is completely covered with a thermal insulation layer to insulate the heat generated by the compressor 1 .

[0124] Preferably, the insulation material of the outer surface of the compressor 1 is selected as an acoustic bag. The material of the acoustic bag can not only reduce the noise of the compressor 1, but also effectively prevent the heat of the compressor 1 from dissipating into the surrounding air. The heat generated by the compressor 1 can be circulated to heat the battery pack 20.

[0125] Therefore, the refrigeration cycle loop includes a compressor 1, a first refrigeration solenoid valve 6, an outdoor heat exchanger 2, a refrigeration electronic expansion valve 3, an indoor heat exchanger 4, a second refrigeration solenoid valve 7, and a gas-liquid separator 5, which are connected end to end. During the refrigeration cycle, the compressor 1 discharges high-temperature and high-pressure refrigerant gas, which enters the outdoor heat exchanger 2 through the first refrigeration solenoid valve 6 to release heat (the average temperature of the refrigerant during this process is about 40-60°C). After cooling, it becomes a liquid at a sub-high temperature and high pressure and flows out. The liquid refrigerant flows through the refrigeration electronic expansion valve 3, where it is throttled and reduced in pressure, becoming a low-temperature and low-pressure gas-liquid two-phase flow. The gas-liquid two-phase flow enters the indoor heat exchanger 4 to cool the air inside the vehicle. After absorbing heat, the refrigerant becomes a sub-low-temperature and low-pressure gas, which flows through the second refrigeration solenoid valve 7 into the gas-liquid separator 5. The sub-low-temperature and low-pressure gaseous refrigerant is then re-absorbed into the compressor 1 and compressed into a high-temperature and high-pressure gaseous refrigerant.

[0126] The heating cycle includes a compressor 1, a first heating solenoid valve 9, an indoor heat exchanger 4, a heating electronic expansion valve 8, an outdoor heat exchanger 2, a second heating solenoid valve 10, and a gas-liquid separator 5, all connected end-to-end. During the heating cycle, compressor 1 compresses the refrigerant, discharging high-temperature, high-pressure refrigerant gas. This gas then passes through the first heating solenoid valve 9 and enters the indoor heat exchanger 4. There, the refrigerant exchanges heat with the cool air inside the vehicle, heating the air (the average refrigerant temperature during this process is approximately 40-60°C). The high-temperature, high-pressure refrigerant gas is cooled by the heat exchange and converted into a liquid at a lower temperature and pressure. This liquid is then discharged from the outlet of the indoor heat exchanger 4, forming two branches.

[0127] Therefore, outdoor heat exchanger 2 is part of the refrigerant cycle, independent of the battery pack's water cycle. When the passenger compartment requires cooling, the temperature of outdoor heat exchanger 2 (serving as a condenser) can be raised (unaffected by the battery safety temperature), increasing the temperature difference between outdoor heat exchanger 2 and the ambient air, thereby increasing heat dissipation. When heating the passenger compartment, the air conditioning thermal management system's refrigerant cycle and the battery pack's water cycle utilize two heat exchangers, simultaneously cooling and heating the battery pack to maintain its temperature. Furthermore, outdoor heat exchanger 2 (serving as an evaporator) can reach temperatures of -40°C, absorbing heat from the -20°C ambient air to meet heating needs.

[0128] Specifically, see Figure 1 As shown, in an embodiment of the present invention, a condenser solenoid valve 14 is provided between the compressor 1 and the second inlet of the condenser 17, the evaporator 18 and the condenser 17 are connected in series to form a first parallel branch, and the first parallel branch is connected in series with the gas-liquid separator 5 and the compressor 1.

[0129] Specifically, see Figure 1As shown, in an embodiment of the present invention, the automobile non-frost heat pump system also includes a second parallel branch formed by the first evaporation solenoid valve 22, the evaporator solenoid valve 16, the condenser 17, the evaporator electronic expansion valve 15, and the evaporator 18 being fluidly connected in sequence. The second parallel branch is located after the indoor heat exchanger 4 in the heating cycle loop, and is arranged in series with the pipeline between the gas-liquid separator 5. The outlet of the gas-liquid separator 5 is fluidly connected to the inlet of the compressor 1.

[0130] Specifically, see Figure 1 As shown, in an embodiment of the present invention, the automobile non-frost heat pump system also includes a second evaporation solenoid valve 23, a battery pack solenoid valve 21, an evaporator electronic expansion valve 15, and an evaporator 18 which are fluidly connected in sequence to form a third parallel branch. The third parallel branch is connected in series with a pipeline located after the outdoor heat exchanger 2 and between the gas-liquid separator 5 in the refrigeration cycle loop, and the outlet of the gas-liquid separator 5 is fluidly connected to the inlet of the compressor 1.

[0131] In another embodiment of the present invention, based on but not limited to the above embodiment, this embodiment further includes a first three-way valve, which replaces the first cooling solenoid valve 6 and the first heating solenoid valve 9 .

[0132] In another embodiment of the present invention, based on but not limited to the above embodiment, this embodiment further includes a second three-way valve, and the second three-way valve replaces the second heating solenoid valve 10 .

[0133] In another embodiment of the present invention, based on but not limited to the above embodiment, this embodiment further includes a third three-way valve, which replaces the second evaporation solenoid valve 23 .

[0134] In another embodiment of the present invention, based on but not limited to the above embodiment, solenoid valves are respectively provided at the bypass line and the input end of the battery pack 20 in this embodiment.

[0135] In another embodiment of the present invention, different from the above embodiment, a fourth three-way valve 24 is provided at the input end of the battery pack 20 of this embodiment, and the third outlet of the fourth three-way valve 24 is fluidically connected to the bypass line.

[0136] It is worth noting that the present invention mainly realizes the on-off of the pipeline formed by the compressor 1, outdoor heat exchanger 2, indoor heat exchanger 4, refrigeration electronic expansion valve 3, heating electronic expansion valve 8, battery pack 20, evaporator 18 and condenser 17, and evaporator electronic expansion valve 15 through valves with different passages. Therefore, there are many ways to implement it, but as long as it belongs to the technical solution under the same concept of the present invention, it should fall within the scope of protection of the present invention.

[0137] Specifically, see Figure 1As shown, in the embodiment of the present invention, the hydrogen-powered vehicle frost-free heat pump system further includes a main air blower 11. The main air blower 11 and the indoor heat exchanger 4 are both located in the HVAC air conditioning box housing 13. Thus, the main air blower 11 can be used to further accelerate the heat exchange effect in the passenger compartment.

[0138] Specifically, in the embodiment of the present invention, the main air blower 11 is a variable frequency blower or a variable speed blower. The advantage of such a setting is that the main air blower 11 can be automatically turned on and off according to signal feedback, which is more intelligent.

[0139] Specifically, in an embodiment of the present invention, the outdoor heat exchanger 2 and the indoor heat exchanger 4 are any one of the structural forms of tube-fin, stacked or parallel flow heat exchangers. In addition, a cooling axial flow fan 12 is also provided on one side of the outdoor heat exchanger 2 to further accelerate the heat exchange speed of the outdoor heat exchanger 2.

[0140] See also Figure 13 As shown, the present invention also provides a thermal management method, which is applied to the above-mentioned hydrogen-powered vehicle non-frost heat pump system without a PTC heater, and the thermal management method comprises the following steps:

[0141] S1: Acquire a passenger compartment thermal management mode; wherein the passenger compartment thermal management mode includes a passenger compartment heating mode, a passenger compartment cooling mode, and a passenger compartment no-demand mode;

[0142] S2: Obtaining a battery pack thermal management mode; wherein the battery pack thermal management mode includes a battery pack no-demand mode, a battery pack average temperature mode, a battery pack heating mode, and a battery pack cooling mode;

[0143] S3: Control the on-off state of the pipelines formed by the compressor 1, the outdoor heat exchanger 2, the indoor heat exchanger 4, the cooling electronic expansion valve 3, the heating electronic expansion valve 8, the battery pack 20, the evaporator 18 and the condenser 17, and the evaporator electronic expansion valve 15, as well as their respective operating states, so that the operation of the hydrogen-powered automobile heat pump system based on the circulating water circuit without a PTC heater meets the thermal management mode of the passenger compartment and the thermal management mode of the battery pack.

[0144] The frost-free heat pump system for hydrogen vehicles in the embodiment of the present invention integrates the thermal management of the passenger compartment and the battery pack. In a low-temperature environment, when the air source heat exchange is insufficient, no high-voltage PTC is required for additional heating. Instead, the compressor 1 running at high speed is used to generate heat to compensate for the problem of insufficient air heat source. The battery pack circuit utilizes the low-freezing-point coolant circulation to absorb the excess refrigerant flow caused by the high-speed operation of compressor 1, preventing frost on the outside of outdoor heat exchanger 2 and liquid hammer in compressor 1, which would deteriorate the efficiency of the heat pump. This allows outdoor heat exchanger 2 to absorb heat from the ambient air at the maximum refrigerant flow rate that does not cause frost. In other words, the air temperature is controlled to not exceed the dew point, ensuring high efficiency of air-source heat exchange. At the same time, the excess refrigerant provided by compressor 1 under the required heating capacity is passed into the series-connected condenser 17 and evaporator 18. After being cooled and heated sequentially by the low-freezing-point cooling water (the circulating water path only serves as a heat capacity component for regulation and neutralization; if the thermal management requirements of the battery pack itself are not considered, it does not consume or increase heat over a long period of time), and is then drawn into compressor 1 while ensuring sufficient superheat. This ensures the smooth and sustainable high-speed operation of compressor 1 at low temperatures, and the total heating power and efficiency of the heat pump at low temperatures. At the same time, the thermal management requirements under various other operating conditions can also be effectively met.

[0145] The working principle of the embodiment of the present invention is to realize multiple working modes by switching the electronic valve to meet different needs. The specific working modes are as follows:

[0146] First, in winter, the passenger compartment is heated in mode and the battery pack has no demand:

[0147] When the passenger compartment thermal management mode is the passenger compartment heating mode and the battery pack thermal management mode is the battery pack no-demand mode, step S3 specifically includes the following steps:

[0148] S331: Control the high-temperature and high-pressure working fluid from the compressor 1 to flow through the indoor heat exchanger 4 for cooling to form a sub-high-temperature and high-pressure working fluid and to heat the passenger compartment. A portion of the sub-high-temperature and high-pressure working fluid flows to the heating electronic expansion valve 8, is throttled and reduced in pressure to form a low-temperature and low-pressure working fluid, and then flows to the outdoor heat exchanger 2 to cool the ambient air to a temperature not lower than its dew point temperature, and then heats it to form a sub-low-temperature and low-pressure working fluid and then flows to the compressor 1. The remaining portion of the sub-high-temperature and high-pressure working fluid flows to the condenser 17 for cooling, and then is throttled and reduced in pressure by the evaporator electronic expansion valve 15, and then flows to the evaporator 18 for heating to form a sub-low-temperature and low-pressure working fluid and then flows to the compressor 1. Control the working fluid in the battery pack thermal management circulation loop to flow through the bypass pipe, condenser 17, and evaporator 18 in sequence under the action of the water pump 19.

[0149] S332: Adjust the opening of the thermoelectronic expansion valve 8 according to the ambient air being cooled to a temperature not lower than its dew point temperature and the superheat of the low-temperature, low-pressure working fluid discharged from the outdoor heat exchanger 2;

[0150] S333: regulating the speed of compressor 1 according to the required heating amount of the heating demand and the heat provided by the ambient air;

[0151] S334 : According to the opening of the heating electronic expansion valve 8 and the rotation speed of the compressor 1 , the flow rate of the sub-high temperature and high pressure working medium flowing to the evaporator 18 and the opening of the evaporator electronic expansion valve 15 are regulated.

[0152] Please refer to the following for details: Figure 2 As shown, at this time, only the first heating solenoid valve 9, the first heating electronic expansion valve 8, the second heating solenoid valve 10, the first evaporation solenoid valve 22, the evaporator solenoid valve 16 and the evaporator electronic expansion valve 15 are in the open state, the second cooling solenoid valve 7, the second evaporation solenoid valve 23, the water-cooled condenser solenoid valve 14, the battery pack solenoid valve 21 and the cooling electronic expansion valve 3 are in the closed state, and the three-way joint of the circulating water circuit is only connected to the short-circuit line, so that the battery line is in the closed state. Preferably, in this embodiment, the compressor 1 is in electric working mode and can automatically control the working state according to the signal.

[0153] In this mode, the opening of the first heating electronic expansion valve 8 is adjusted according to the real-time temperature of the ambient air after cooling in the passenger compartment and the superheat of the refrigerant at the outlet of the outdoor heat exchanger 2 (refrigerant superheat: refers to the difference between the saturation temperature corresponding to the refrigerant pressure at a certain point at the outlet of the outdoor heat exchanger 2 and the actual temperature of the refrigerant); the speed of the compressor 1 is regulated according to the heat provided by the ambient air and the required heating amount; and the opening of the evaporator electronic expansion valve 15 and the refrigerant flow rate Q1 in the evaporator 18 flow path are regulated according to the opening of the first heating electronic expansion valve 8 and the speed of the compressor 1.

[0154] The compressor 1 performs work on the refrigerant by compressing it, and discharges high-temperature and high-pressure refrigerant gas, which then enters the indoor heat exchanger 4 through the first heating solenoid valve 9. In the indoor heat exchanger 4, the refrigerant exchanges heat with the cold air in the vehicle, thereby heating the air in the vehicle (the average temperature of the refrigerant in this process is about 40-60°C). The high-temperature and high-pressure refrigerant gas is cooled by heat exchange and becomes a liquid of a second high temperature and high pressure, and is discharged from the outlet of the indoor heat exchanger 4 to form two branches, namely the first circulation branch and the second circulation branch.

[0155] Among them, part of the refrigerant in the first circulation branch flows through the first heating electronic expansion valve 8 (heating electronic expansion valve), and the refrigerant is throttled and reduced in pressure in the first heating electronic expansion valve 8, becoming a low-temperature and low-pressure gas-liquid two-phase flow. The gas-liquid two-phase flow enters the outdoor heat exchanger 2 to absorb heat, and cools the ambient air to above its dew point (the temperature at which the original unsaturated vapor in the air becomes saturated vapor due to the drop in temperature, which is called the dew point. When the dew point is reached, the temperature drops further, and part of the water vapor in the air condenses into small water droplets and adheres to objects on the ground, forming dew). After absorbing heat, the refrigerant becomes a sub-low-temperature and low-pressure gas and flows into the gas-liquid separator 5 through the second heating solenoid valve 10. The sub-low-temperature and low-pressure gaseous refrigerant in the gas-liquid separator 5 is re-inhaled into the compressor 1 and compressed into a high-temperature and high-pressure gaseous refrigerant.

[0156] The second circulation branch is that the remaining refrigerant discharged from the outlet of the indoor heat exchanger 4 passes through the first evaporation solenoid valve 22 and the evaporator solenoid valve 16 and enters the condenser 17 to release heat, and then enters the evaporator 18 to absorb heat after throttling by the evaporator electronic expansion valve 15. The refrigerant after absorbing heat becomes a sub-low temperature and low pressure gas and flows into the gas-liquid separator 5. The sub-low temperature and low pressure gaseous refrigerant in the gas-liquid separator 5 is re-absorbed into the compressor 1 and compressed into a high temperature and high pressure gaseous refrigerant.

[0157] When the superheat of the refrigerant at the outlet of the evaporator 18 is lower than a preset threshold, the heat pump system enters the following second mode, that is, the passenger compartment heating mode and the battery pack temperature equalization mode. At this time, the circulating water circuit is heated, and after the water temperature reaches the average temperature of the battery pack and the maximum temperature limit of its no-demand state, it returns to the first mode.

[0158] Second mode: Winter passenger compartment heating mode and battery pack temperature equalization mode:

[0159] When the passenger compartment thermal management mode is the passenger compartment heating mode and the battery pack thermal management mode is the battery pack temperature equalization mode, step S3 specifically includes the following steps:

[0160] S301: Control a portion of the high-temperature and high-pressure working fluid from the compressor 1 to flow through the indoor heat exchanger 4 for cooling to form a sub-high-temperature and high-pressure working fluid and to heat the passenger compartment; the remaining portion of the high-temperature and high-pressure working fluid from the compressor 1 flows through the condenser 17 for cooling to form a sub-high-temperature and high-pressure working fluid; a portion of the working fluid after the two portions of the sub-high-temperature and high-pressure working fluid are mixed flows to the heating electronic expansion valve 8, is throttled and reduced in pressure to form a low-temperature and low-pressure working fluid, and then flows to the outdoor heat exchanger 2 to cool the ambient air to a temperature not lower than its dew point temperature, and is heated to form a sub-low-temperature and low-pressure working fluid and then flows to the compressor 1; the remaining portion of the working fluid after the two portions of the sub-high-temperature and high-pressure working fluid are mixed flows to the evaporator electronic expansion valve 15, is throttled and reduced in pressure, and then flows to the evaporator 18 for heating to form a sub-low-temperature and low-pressure working fluid and then flows to the compressor 1; control the working fluid of the battery pack thermal management circulation loop to flow through the battery pack 20, the evaporator 18 and the condenser 17 in sequence under the action of the water pump 19;

[0161] S302: Adjusting the opening of the thermoelectronic expansion valve 8 based on the ambient air being cooled to a temperature not lower than its dew point temperature and the superheat of the low-temperature, low-pressure working fluid exiting the outdoor heat exchanger 2;

[0162] S303: regulating the speed of compressor 1 according to the required heating amount in the passenger cabin heating mode and the heat provided by the ambient air;

[0163] S304: Regulating the flow rate of the sub-high temperature and high pressure working fluid to the evaporator 18 and the opening of the evaporator electronic expansion valve 15 according to the opening of the heating electronic expansion valve 8 and the speed of the compressor 1;

[0164] S305 : According to the superheat of the sub-low temperature and low pressure working medium discharged from the evaporator 18 and the water inlet temperature of the battery pack, the flow rate of the high temperature and high pressure working medium flowing from the compressor 1 to the condenser 17 is regulated.

[0165] See also Figure 3 As shown, in the battery pack temperature equalization mode, only the first heating solenoid valve 9, the first heating electronic expansion valve 8, the second heating solenoid valve 10, the first evaporation solenoid valve 22, the battery pack solenoid valve 21, the water-cooled condenser solenoid valve 14 and the evaporator electronic expansion valve 15 are in the open state, and the second cooling solenoid valve 7, the evaporator solenoid valve 16, the second evaporation solenoid valve 23, and the cooling electronic expansion valve 3 of other refrigerant circuits are in the closed state. The T-joint of the circulating water circuit is only connected to the battery circuit, and the short-circuit circuit is closed.

[0166] In the battery pack temperature equalization mode, the opening of the first heating electronic expansion valve 8 is adjusted according to the temperature of the cooled ambient air in the passenger compartment and the superheat of the refrigerant at the outlet of the outdoor heat exchanger 2; the speed of the compressor 1 is regulated according to the heat provided by the ambient air and the required heating amount; the opening of the evaporator electronic expansion valve 15 and the refrigerant flow rate Q1 in the evaporator 18 flow path are regulated according to the opening of the first heating electronic expansion valve 8 and the speed of the compressor 1.

[0167] The opening and closing ratio of the water-cooled condenser solenoid valve 14 is controlled according to the superheat of the refrigerant at the outlet of the evaporator 18 and the water inlet temperature of the battery pack 20 .

[0168] Compressor 1 discharges high-temperature and high-pressure refrigerant gas, forming two circulation branches:

[0169] A portion of the high-temperature and high-pressure refrigerant gas enters the indoor heat exchanger 4 through the first heating solenoid valve 9, and performs heat exchange heating on the air in the vehicle (the average temperature of the refrigerant in this process is about 40-60°C). After the refrigerant gas is cooled, a portion of it becomes a liquid with a sub-high temperature and high pressure and flows out; the other remaining portion of the high-temperature and high-pressure refrigerant gas enters the condenser 17 through the water-cooled condenser solenoid valve 14 to release heat, and after cooling, it becomes a liquid with a sub-high temperature and high pressure and flows out, and is connected to the first circulation branch through the battery pack solenoid valve 21 and the first evaporation solenoid valve 22.

[0170] The two parts of refrigerant are connected through the first evaporator solenoid valve 22 and the battery pack solenoid valve 21. Part of the combined liquid refrigerant flows through the first heating electronic expansion valve 8, is throttled and reduced in pressure, becomes a low-temperature and low-pressure gas-liquid two-phase flow, and enters the outdoor heat exchanger 2 to absorb heat, cooling the ambient air to above its dew point temperature. The refrigerant after absorbing heat becomes a sub-low-temperature and low-pressure gas, and flows into the gas-liquid separator 5 through the second heating solenoid valve 10; the remaining refrigerant enters the water-cooled evaporator 18 after throttling by the evaporator electronic expansion valve 15 to absorb heat. The refrigerant after absorbing heat becomes a sub-low-temperature and low-pressure gas and flows into the gas-liquid separator 5. The sub-low-temperature and low-pressure gaseous refrigerant in the gas-liquid separator 5 is re-inhaled into the compressor 1 and compressed into a high-temperature and high-pressure gaseous refrigerant.

[0171] The third mode: winter passenger compartment heating mode and battery pack heating mode:

[0172] S306: Control a portion of the high-temperature, high-pressure working fluid from the compressor 1 to flow through the indoor heat exchanger 4 for cooling to form a sub-high-temperature, high-pressure working fluid. The fluid then flows to the heating electronic expansion valve 8 for throttling and reducing the pressure to form a low-temperature, low-pressure working fluid, and then flows to the outdoor heat exchanger 2 to cool the ambient air to a temperature not lower than its dew point. The fluid then flows to form a sub-low-temperature, low-pressure working fluid and then flows to the compressor 1. The remaining portion of the high-temperature, high-pressure working fluid from the compressor 1 flows through the condenser 17 for cooling to form a sub-high-temperature, high-pressure working fluid, and then flows to the evaporator electronic expansion valve 15 for throttling and reducing the pressure to form a sub-low-temperature, low-pressure working fluid and then flows to the compressor 1. Control the working fluid in the battery pack thermal management loop to flow sequentially through the battery pack 20, the evaporator 18, and the condenser 17 under the action of the water pump 19.

[0173] S307: Adjust the opening of the thermoelectronic expansion valve 8 according to the ambient air being cooled to a temperature not lower than its dew point temperature and the superheat of the low-temperature, low-pressure working fluid exiting the outdoor heat exchanger 2;

[0174] S308: regulating the speed of compressor 1 according to the required heating amount of the heating demand and the heat provided by the ambient air;

[0175] S309: Regulating the flow rate of the sub-high temperature and high pressure working fluid to the evaporator 18 and the opening of the evaporator electronic expansion valve 15 according to the opening of the heating electronic expansion valve 8 and the speed of the compressor 1;

[0176] S310: Regulating the flow of the high-temperature and high-pressure working medium to the condenser 17 according to the superheat of the sub-low-temperature and low-pressure working medium from the evaporator 18 and the water inlet temperature of the battery pack.

[0177] Please refer to the following for details: Figure 4 As shown, in the battery pack heating mode, only the first heating solenoid valve 9, the first heating electronic expansion valve 8, the second heating solenoid valve 10, the water-cooled condenser solenoid valve 14 and the evaporator electronic expansion valve 15 are open, and the second cooling solenoid valve 7, the first evaporation solenoid valve 22, the second evaporation solenoid valve 23, the battery pack solenoid valve 21 and the evaporator solenoid valve 16 of other refrigerant circuits are closed, the T-joint of the circulating water circuit is only connected to the battery circuit, and the short-circuit circuit is closed.

[0178] In this mode, the opening of the first heating electronic expansion valve 8 is adjusted according to the temperature of the cooled ambient air in the passenger compartment and the superheat of the refrigerant at the outlet of the outdoor heat exchanger 2; the speed of the compressor 1 is regulated according to the heat provided by the ambient air and the required heating amount; the refrigerant flow Q1 in the evaporator 18 flow path and the opening of the evaporator electronic expansion valve 15 are regulated according to the opening of the first heating electronic expansion valve 8 and the speed of the compressor 1; the opening and closing ratio of the water-cooled condenser solenoid valve 14 is controlled according to the superheat of the refrigerant at the outlet of the evaporator 18 and the water inlet temperature of the battery pack 20.

[0179] Compressor 1 discharges high-temperature and high-pressure refrigerant gas, forming two circulation branches:

[0180] A portion of the high-temperature and high-pressure refrigerant gas enters the indoor heat exchanger 4 through the first heating solenoid valve 9 to heat the air in the vehicle (the average temperature of the refrigerant during the process is about 40-60°C), and after cooling, it becomes a sub-high-temperature and high-pressure liquid and flows out. Part of the liquid refrigerant flows through the first heating electronic expansion valve 8, is throttled and reduced in pressure, and becomes a low-temperature and low-pressure gas-liquid two-phase flow and enters the outdoor heat exchanger 2 to absorb heat, cooling the ambient air to above its dew point temperature. After absorbing heat, the refrigerant becomes a sub-low-temperature and low-pressure gas and flows into the gas-liquid separator 5 through the second heating solenoid valve 10. The sub-low-temperature and low-pressure gaseous refrigerant in the gas-liquid separator 5 is re-absorbed into the compressor 1 and compressed into a high-temperature and high-pressure gaseous refrigerant.

[0181] The remaining refrigerant enters the condenser 17 through the water-cooled condenser solenoid valve 14 to release heat, and after cooling, it becomes a sub-high temperature and high pressure liquid and flows out. After being throttled by the evaporator electronic expansion valve 15, it enters the evaporator 18 to absorb heat. After absorbing heat, the refrigerant becomes a sub-low temperature and low pressure gas and flows into the gas-liquid separator 5. The sub-low temperature and low pressure gaseous refrigerant in the gas-liquid separator 5 is re-inhaled into the compressor and compressed into a high temperature and high pressure gaseous refrigerant.

[0182] Fourth mode: Winter passenger compartment heating mode and battery pack cooling mode:

[0183] When the passenger compartment thermal management mode is the passenger compartment heating mode and the battery pack thermal management mode is the battery pack cooling mode, step S3 specifically includes the following steps:

[0184] S311: Control the high-temperature and high-pressure working fluid output by the compressor 1 to flow through the indoor heat exchanger 4 to cool down and form a sub-high-temperature and high-pressure working fluid and realize the heating of the passenger compartment. A part of the sub-high-temperature and high-pressure working fluid flows to the heating electronic expansion valve 8, is throttled and reduced in pressure to form a low-temperature and low-pressure working fluid, and then flows to the outdoor heat exchanger 2 to cool the ambient air to a temperature not lower than its dew point temperature and heat it to form a sub-low-temperature and low-pressure working fluid and then flows to the compressor 1. The remaining part of the sub-high-temperature and high-pressure working fluid flows to the evaporator electronic expansion valve 15, is throttled and reduced in pressure, and then flows to the evaporator 18 to heat it to form a sub-low-temperature and low-pressure working fluid and then flows to the compressor 1; control the working fluid of the battery pack thermal management circulation loop to flow through the battery pack 20, evaporator 18, and condenser 17 in sequence under the action of the water pump 19.

[0185] S312: Adjusting the opening of the thermoelectronic expansion valve 8 according to the ambient air being cooled to a temperature not lower than its dew point temperature and the superheat of the low-temperature, low-pressure working fluid discharged from the outdoor heat exchanger 2;

[0186] S313: regulating the speed of compressor 1 according to the required heating amount of the heating demand and the heat provided by the ambient air;

[0187] S314 : According to the opening of the heating electronic expansion valve 8 and the rotation speed of the compressor 1 , the flow rate of the sub-high temperature and high pressure working medium flowing to the evaporator 18 and the opening of the evaporator electronic expansion valve 15 are regulated.

[0188] Please refer to the following for details: Figure 5 As shown, in the battery pack cooling mode, only the first heating solenoid valve 9, the first heating electronic expansion valve 8, the second heating solenoid valve 10, the first evaporation solenoid valve 22, the battery pack solenoid valve 21 and the evaporator electronic expansion valve 15 are in the open state, and the second cooling solenoid valve 7, the water-cooled condenser solenoid valve 14, the second evaporation solenoid valve 23 and the evaporator solenoid valve 16 of other refrigerant circuits are closed, the T-joint of the circulating water circuit is only connected to the battery circuit, and the short-circuit circuit is closed.

[0189] The compressor 1 discharges high-temperature and high-pressure refrigerant gas, which enters the indoor heat exchanger 4 through the first heating solenoid valve 9 to heat the air in the vehicle (the average temperature of the refrigerant during the process is about 40-60°C), and then turns into a medium-temperature and high-pressure liquid and flows out after cooling.

[0190] The liquid refrigerant part flows through the first heating electronic expansion valve 8, is throttled and reduced in pressure in the first heating electronic expansion valve 8 to become a low-temperature and low-pressure gas-liquid two-phase flow, and the low-temperature and low-pressure gas-liquid two-phase flow enters the outdoor heat exchanger 2 to absorb heat, cooling the ambient air to above its dew point temperature. The refrigerant after absorbing heat becomes a sub-low-temperature and low-pressure gas and flows into the gas-liquid separator 5 through the second heating solenoid valve 10. The sub-low-temperature and low-pressure gaseous refrigerant in the gas-liquid separator 5 is re-inhaled into the compressor and compressed into a high-temperature and high-pressure gaseous refrigerant.

[0191] The remaining refrigerant flows through the first evaporation solenoid valve 22 and the battery pack solenoid valve 21, and after being throttled by the evaporator electronic expansion valve 15, enters the evaporator 18 to absorb heat. After absorbing heat, the refrigerant becomes a sub-low temperature and low pressure gas and flows into the gas-liquid separator 5. The sub-low temperature and low pressure gaseous refrigerant is re-inhaled into the compressor and compressed into a high temperature and high pressure gaseous refrigerant.

[0192] In this mode, the opening of the heating electronic expansion valve 8 is adjusted according to the temperature of the cooled ambient air and the superheat of the refrigerant at the outdoor heat exchanger outlet. The compressor speed is regulated according to the heat provided by the ambient air, the heat dissipation of the battery pack and the required heating amount. The refrigerant flow in the water-cooled evaporator flow path and the opening of the electronic expansion valve 15 are regulated based on the former two.

[0193] Fifth mode: Summer passenger compartment cooling mode and battery pack cooling mode:

[0194] When the passenger compartment thermal management mode is the passenger compartment cooling mode and the battery pack thermal management mode is the battery pack cooling mode, step S3 specifically includes the following steps:

[0195] S315: Control the high-temperature and high-pressure working fluid output from the compressor 1 to flow through the outdoor heat exchanger 2 for cooling to form a sub-high-temperature and high-pressure working fluid. Part of the sub-high-temperature and high-pressure working fluid flows to the refrigeration electronic expansion valve 3, is throttled and reduced in pressure to form a low-temperature and low-pressure working fluid, and then flows to the indoor heat exchanger 4 to heat up to form a sub-low-temperature and low-pressure working fluid to achieve passenger compartment cooling and then flows to the compressor 1. The remaining part of the sub-high-temperature and high-pressure working fluid flows to the evaporator electronic expansion valve 15, is throttled and reduced in pressure, and then flows to the evaporator 18 to heat up to form a sub-low-temperature and low-pressure working fluid and then flows to the compressor 1; control the working fluid of the battery pack thermal management circulation loop to flow through the battery pack 20, evaporator 18, and condenser 17 in sequence under the action of the water pump 19.

[0196] S316: According to the required cooling capacity of the refrigeration demand and the required heat dissipation of the battery pack, the speed of the compressor 1, the opening of the refrigeration electronic expansion valve 3, and the opening of the evaporator electronic expansion valve 15 are adjusted.

[0197] Please refer to the following for details: Figure 6 As shown, when the battery pack is in cooling mode, only the first refrigeration solenoid valve 6, the refrigeration electronic expansion valve 3, the second refrigeration solenoid valve 7, the second evaporation solenoid valve 23, the battery pack solenoid valve 21 and the evaporator electronic expansion valve 15 are open, and the heating electronic expansion valve 8, the first heating solenoid valve 9, the second heating solenoid valve 10, the water-cooled condenser solenoid valve 14, the evaporator solenoid valve 16 and the second evaporation solenoid valve 23 of other refrigerant circuits are closed, the T-joint of the circulating water circuit is only connected to the battery circuit, and the short-circuit circuit is closed.

[0198] At this time, the compressor 1 discharges high-temperature and high-pressure refrigerant gas, which enters the outdoor heat exchanger 2 through the first refrigeration solenoid valve 6 to release heat (the average temperature of the refrigerant in this process is about 40-60°C). After cooling, the high-temperature and high-pressure refrigerant gas turns into a second-high-temperature and high-pressure liquid and flows out, forming two branches.

[0199] Part of the liquid refrigerant in one branch flows through the refrigeration electronic expansion valve 3, where it is throttled and depressurized to become a low-temperature, low-pressure gas-liquid two-phase flow. The gas-liquid two-phase flow enters the indoor heat exchanger 4 and cools the air inside the vehicle. After absorbing heat, the refrigerant becomes a sub-low-temperature, low-pressure gas and flows through the second refrigeration solenoid valve 7 into the gas-liquid separator 5.

[0200] The remaining refrigerant in the other branch flows through the second evaporation solenoid valve 23 and the battery pack solenoid valve 21, and after being throttled by the evaporator electronic expansion valve 15, enters the water-cooled evaporator 18 to absorb heat. After absorbing heat, the refrigerant becomes a sub-low temperature and low pressure gas and flows into the gas-liquid separator 5. Then, the sub-low temperature and low pressure gaseous refrigerant is re-inhaled into the compressor 1 and compressed into a high temperature and high pressure gaseous refrigerant.

[0201] In this mode, the speed of the compressor 1 and the openings of the refrigeration electronic expansion valve 3 and the evaporator electronic expansion valve 15 are regulated according to the heat dissipation of the battery pack 20 and the required cooling capacity of the passenger compartment.

[0202] Sixth mode: summer passenger compartment cooling mode and battery pack heating mode:

[0203] When the passenger compartment thermal management mode is the cooling mode and the battery pack thermal management mode is the heating mode, step S3 specifically includes the following steps:

[0204] S317: Controlling the high-temperature, high-pressure working fluid from the compressor 1 to flow to the condenser 17 for cooling to form a sub-high-temperature, high-pressure working fluid. The sub-high-temperature, high-pressure working fluid flows to the condenser 17 to release heat (the average temperature of the refrigerant during this process is approximately 40-60°C). After cooling, it becomes a sub-high-temperature, high-pressure liquid working fluid and flows out. A portion of the sub-high-temperature, high-pressure working fluid passes through the battery pack solenoid valve 21 and the second evaporation solenoid valve 23 and flows to the refrigeration electronic expansion valve 3, where it is throttled and reduced in pressure to form a low-temperature, low-pressure working fluid. The low-temperature, low-pressure working fluid then flows to the indoor heat exchanger 4 for heating to form a sub-low-temperature, low-pressure working fluid, thereby cooling the passenger compartment before flowing to the compressor 1. The remaining portion of the sub-high-temperature, high-pressure working fluid flows to the evaporator electronic expansion valve 15, where it is throttled and reduced in pressure, and then flows to the evaporator 18 for heating to form a sub-low-temperature, low-pressure working fluid before flowing to the compressor 1. Controlling the working fluid in the battery pack thermal management loop to flow sequentially through the battery pack 20, the evaporator 18, and the condenser 17 under the action of the water pump 19.

[0205] S318 : According to the required cooling capacity of the refrigeration demand and the required heating capacity of the battery pack 20 , the speed of the compressor 1 , the opening of the refrigeration electronic expansion valve 3 , and the opening of the evaporator electronic expansion valve 15 are regulated.

[0206] Please refer to the following for details: Figure 7 As shown, in the battery pack heating mode, only the condenser solenoid valve 14, the battery pack solenoid valve 21, the evaporator electronic expansion valve 15, the second evaporation solenoid valve 23, the cooling electronic expansion valve 3 and the second cooling solenoid valve 7 are open, and the heating electronic expansion valve 8, the first heating solenoid valve 9, the second heating solenoid valve 10, the evaporator solenoid valve 16, the first evaporation solenoid valve 22 and the first cooling solenoid valve 6 of other refrigerant circuits are closed, the T-joint of the circulating water circuit is only connected to the battery circuit, and the short-circuit circuit is closed.

[0207] As a result, the compressor 1 discharges high-temperature and high-pressure refrigerant gas, which enters the condenser 17 through the condenser solenoid valve 14 to release heat (the average temperature of the refrigerant during the process is about 40-60°C). After cooling, it turns into a liquid of a lower temperature and high pressure and flows out, forming two branches:

[0208] Part of the liquid refrigerant in one of the branches passes through the battery pack solenoid valve 21 and the second evaporation solenoid valve 23 and flows through the refrigeration electronic expansion valve 3. It is throttled and reduced in pressure in the refrigeration electronic expansion valve 3 to become a low-temperature and low-pressure gas-liquid two-phase flow. The gas-liquid two-phase flow enters the indoor heat exchanger 4 to cool the air in the vehicle, and the refrigerant after absorbing heat becomes a sub-low-temperature and low-pressure gas and flows into the gas-liquid separator 5 through the second refrigeration solenoid valve 7.

[0209] The remaining refrigerant in the other branch enters the evaporator 18 to absorb heat after being throttled by the evaporator electronic expansion valve 15. After absorbing heat, the refrigerant becomes a sub-low temperature and low pressure gas and flows into the gas-liquid separator 5. The sub-low temperature and low pressure gaseous refrigerant is re-inhaled into the compressor 1 and compressed into a high temperature and high pressure gaseous refrigerant.

[0210] In this mode, the speed of the compressor 1 and the openings of the refrigeration electronic expansion valve 3 and the evaporator electronic expansion valve 15 are regulated according to the required heating capacity of the battery pack 20 and the required cooling capacity of the passenger compartment.

[0211] Seventh mode: Summer passenger compartment cooling mode and battery pack temperature equalization mode:

[0212] When the passenger compartment thermal management mode is the passenger compartment cooling mode and the battery pack thermal management mode is the battery pack temperature equalization mode, step S3 specifically includes the following steps:

[0213] S319: Control the high-temperature, high-pressure working fluid from compressor 1 to flow through outdoor heat exchanger 2 for cooling to form a sub-high-temperature, high-pressure working fluid. The working fluid then flows to refrigeration electronic expansion valve 3 for throttling and pressure reduction to form a low-temperature, low-pressure working fluid. The working fluid then flows to indoor heat exchanger 4 for heating to form a sub-low-temperature, low-pressure working fluid to cool the passenger compartment before flowing to compressor 1. Control the working fluid in the battery pack thermal management loop to flow sequentially through battery pack 20, condenser 17, and evaporator 18 under the action of water pump 19.

[0214] S320: regulating the speed of the compressor 1 according to the required cooling capacity of the cooling demand;

[0215] S321: regulating the opening of the refrigeration electronic expansion valve 3 according to the superheat of the sub-low temperature and low pressure working medium output from the indoor heat exchanger.

[0216] Please refer to the following for details: Figure 8 As shown, in the battery pack temperature equalization mode, only the first cooling solenoid valve 6, the cooling electronic expansion valve 3, and the second cooling solenoid valve 7 are open, and the heating electronic expansion valve 8, the first heating solenoid valve 9, the second heating solenoid valve 10, the condenser solenoid valve 14, the evaporator electronic expansion valve 15, the evaporator solenoid valve 16, the battery pack solenoid valve 21, the first evaporation solenoid valve 22, and the second evaporation solenoid valve 23 of other refrigerant circuits are closed. The T-joint of the circulating water circuit is only connected to the battery circuit, and the short-circuit circuit is closed.

[0217] Compressor 1 discharges high-temperature, high-pressure refrigerant gas, which then passes through first refrigeration solenoid valve 6 and enters outdoor heat exchanger 2, where it releases heat (the average refrigerant temperature during this process is approximately 40-60°C). After cooling, it becomes a sub-high-temperature, high-pressure liquid and flows out. The liquid refrigerant then flows through electronic refrigeration expansion valve 3, where it is throttled and depressurized, becoming a low-temperature, low-pressure gas-liquid two-phase flow. This gas-liquid two-phase flow then enters indoor heat exchanger 4 to cool the air inside the vehicle. After absorbing heat, the refrigerant becomes a sub-low-temperature, low-pressure gas, which then passes through second refrigeration solenoid valve 7 and flows into gas-liquid separator 5. The sub-low-temperature, low-pressure gaseous refrigerant is then re-drawn into compressor 1 and compressed into a high-temperature, high-pressure gaseous refrigerant.

[0218] In this mode, the speed of the compressor 1 is regulated according to the cooling capacity required by the passenger compartment, and the opening of the refrigeration electronic expansion valve 3 is regulated according to the superheat of the refrigerant at the outlet of the indoor heat exchanger 4.

[0219] Mode 8: Summer passenger cabin cooling and no battery pack demand mode:

[0220] When the passenger compartment thermal management mode is the passenger compartment cooling mode and the battery pack thermal management mode is the battery pack no-demand mode, step S3 specifically includes the following steps:

[0221] S322: Control the high-temperature and high-pressure working fluid from compressor 1 to flow through outdoor heat exchanger 2 for cooling to form a sub-high-temperature and high-pressure working fluid, then flow to refrigeration electronic expansion valve 3 for throttling and pressure reduction to form a low-temperature and low-pressure working fluid, then flow to indoor heat exchanger 4 for heating to form a sub-low-temperature and low-pressure working fluid to cool the passenger compartment, and then flow to compressor 1;

[0222] S323: regulating the speed of the compressor 1 according to the required cooling capacity of the passenger compartment cooling mode;

[0223] S324: regulating the opening of the refrigeration electronic expansion valve 3 according to the superheat of the sub-low temperature and low pressure working medium output from the indoor heat exchanger 4.

[0224] Please refer to the following for details: Figure 9 As shown, in the battery pack no-demand mode, only the first cooling solenoid valve 6, the cooling electronic expansion valve 3, and the second cooling solenoid valve 7 are open, and the heating electronic expansion valve 8, the first heating solenoid valve 9, the second heating solenoid valve 10, the condenser solenoid valve 14, the evaporator electronic expansion valve 15, the evaporator solenoid valve 16, the battery pack solenoid valve 21, the first evaporation solenoid valve 22, and the second evaporation solenoid valve 23 of other refrigerant circuits are closed, the T-joint of the circulating water circuit closes the battery circuit, closes the short-circuit circuit, and the circulating water circuit does not work.

[0225] Compressor 1 discharges high-temperature, high-pressure refrigerant gas, which then passes through first refrigeration solenoid valve 6 and enters outdoor heat exchanger 2, where it releases heat (the average refrigerant temperature during this process is approximately 40-60°C). After cooling, it becomes a sub-high-temperature, high-pressure liquid and flows out. The liquid refrigerant then flows through electronic refrigeration expansion valve 3, where it is throttled and depressurized, becoming a low-temperature, low-pressure gas-liquid two-phase flow. This gas-liquid two-phase flow then enters indoor heat exchanger 4 to cool the air inside the vehicle. After absorbing heat, the refrigerant becomes a sub-low-temperature, low-pressure gas, which then passes through second refrigeration solenoid valve 7 and flows into gas-liquid separator 5. The sub-low-temperature, low-pressure gaseous refrigerant is then re-drawn into compressor 1 and compressed into a high-temperature, high-pressure gaseous refrigerant.

[0226] Ninth mode: No demand mode for passenger compartment and battery pack uniform temperature mode:

[0227] S335: Determine whether the superheat of the working fluid discharged from the evaporator 18 is lower than a preset value;

[0228] When the superheat of the working fluid discharged from the evaporator 18 is lower than a preset value, the battery pack thermal management mode is switched from the battery pack no-demand mode to the battery pack uniform temperature mode, and steps S301 to S305 are executed until the water temperature of the battery pack thermal management circulation loop reaches a maximum temperature threshold of not less than the battery no-demand, the battery pack thermal management mode is switched from the battery pack uniform temperature mode to the battery pack no-demand mode, and steps S331 to S334 are executed; otherwise, the battery pack thermal management mode continues to be maintained as the battery pack uniform temperature mode and steps S301 to S305 are executed.

[0229] See also Figure 10 As shown, in the battery pack temperature equalization mode, the refrigerant circuit does not work, only the water pump of the circulating water circuit works, the T-joint is only connected to the battery circuit, and the short-circuit circuit is closed.

[0230] Tenth mode: passenger compartment no-demand mode and battery pack heating mode:

[0231] When the passenger compartment thermal management mode is the passenger compartment no-demand mode and the battery pack thermal management mode is the battery pack heating mode, step S3 specifically includes the following steps:

[0232] S326: Controlling the high-temperature and high-pressure working fluid from the compressor 1 to flow through the condenser 17 for cooling to form a sub-high-temperature and high-pressure working fluid. A portion of the sub-high-temperature and high-pressure working fluid flows to the heating electronic expansion valve 8, is throttled and depressurized to form a low-temperature and low-pressure working fluid, and then flows to the outdoor heat exchanger 2 to cool the ambient air to a temperature not lower than its dew point temperature and heat it to form a sub-low-temperature and low-pressure working fluid, and then flows to the compressor 1. The remaining portion of the sub-high-temperature and high-pressure working fluid flows to the evaporator electronic expansion valve 15, is throttled and depressurized, and then flows to the evaporator 18 for heating to form a sub-low-temperature and low-pressure working fluid, and then flows to the compressor 1; controlling the working fluid in the battery pack thermal management circulation loop to flow through the battery pack, the condenser 17, and the evaporator 18 in sequence under the action of the water pump 19;

[0233] S327: Regulating the speed of the compressor 1, the opening of the heating electronic expansion valve 8, and the opening of the evaporator electronic expansion valve 15 according to the ambient air being cooled to a temperature not lower than its dew point temperature and the required heating amount of the battery pack.

[0234] See also Figure 11 As shown, in the battery pack heating mode, only the condenser solenoid valve 14, the evaporator electronic expansion valve 15, the battery pack solenoid valve 21, the first evaporation solenoid valve 22, the heating electronic expansion valve 8 and the second heating solenoid valve 10 are open, and the first cooling solenoid valve 6, the second cooling solenoid valve 7, the first heating solenoid valve 9, the evaporator solenoid valve 16 and the second evaporation solenoid valve 23 of other refrigerant circuits are closed, the T-joint of the circulating water circuit is only connected to the battery circuit, and the short-circuit circuit is closed.

[0235] Compressor 1 then discharges high-temperature, high-pressure refrigerant gas, which then flows through condenser solenoid valve 14 into condenser 17, where it releases heat (the average refrigerant temperature during this process is approximately 40-60°C). After cooling, it flows out as a sub-high-temperature, high-pressure liquid. A portion of the liquid refrigerant flows through evaporator electronic expansion valve 15, where it is throttled and reduced in pressure, becoming a low-temperature, low-pressure gas-liquid two-phase flow. This flow then flows into evaporator 18, where it cools the coolant. After absorbing heat, the refrigerant becomes a sub-low-temperature, low-pressure gas that flows into gas-liquid separator 5.

[0236] Part of the liquid refrigerant flows through the battery pack solenoid valve 21 and the first evaporation solenoid valve 22, is throttled and reduced in pressure by the heating electronic expansion valve 8, and becomes a low-temperature and low-pressure gas-liquid two-phase flow and enters the outdoor heat exchanger 2 to absorb heat, cooling the ambient air to above its dew point temperature. After absorbing heat, the refrigerant becomes a sub-low-temperature and low-pressure gas and flows into the gas-liquid separator 5 through the second heating solenoid valve 10. The sub-low-temperature and low-pressure gaseous refrigerant is re-inhaled into the compressor 1 and compressed into a high-temperature and high-pressure gaseous refrigerant.

[0237] In this mode, the speed of the compressor 1 and the openings of the heating electronic expansion valve 8 and the evaporator electronic expansion valve 15 are regulated according to the required heating amount of the battery pack 20 and the heat provided by the ambient air.

[0238] Eleventh mode: no demand mode for passenger compartment and battery pack cooling mode:

[0239] When the passenger compartment thermal management mode is the passenger compartment no-demand mode and the battery pack thermal management mode is the battery pack cooling mode, step S3 specifically includes the following steps:

[0240] S328: Control the high-temperature and high-pressure working fluid from the compressor 1 to flow through the outdoor heat exchanger 2 for cooling to form a sub-high-temperature and high-pressure working fluid, then flow to the evaporator electronic expansion valve 15 for throttling and pressure reduction to form a low-temperature and low-pressure working fluid, then flow to the evaporator 18 for heating to form a sub-low-temperature and low-pressure working fluid, and then flow to the compressor 1; control the working fluid in the battery pack thermal management circulation loop to flow through the battery pack, the condenser 17, and the evaporator 18 in sequence under the action of the water pump 19;

[0241] S329: regulating the speed of the compressor 1 according to the required cooling capacity of the battery pack;

[0242] S330 : regulating the opening of the evaporator electronic expansion valve 15 according to the superheat of the sub-high temperature and high pressure working fluid output from the evaporator 18 .

[0243] See also Figure 12 As shown, in the battery pack cooling mode, only the first cooling solenoid valve 6, the second evaporation solenoid valve 23, the battery pack solenoid valve 21 and the evaporator electronic expansion valve 15 are open, and the second cooling solenoid valve 7, the heating electronic expansion valve 8, the first heating solenoid valve 9, the second heating solenoid valve 10, the condenser solenoid valve 14, the evaporator electronic expansion valve 15 and the evaporator solenoid valve 16 of the other refrigerant circuits are closed, the T-joint of the circulating water circuit is only connected to the battery circuit, and the short-circuit circuit is closed.

[0244] Compressor 1 discharges high-temperature, high-pressure refrigerant gas, which then flows through first refrigeration solenoid valve 6 into outdoor heat exchanger 2, where it releases heat (the average refrigerant temperature during this process is approximately 40-60°C). After cooling, it becomes a sub-high-temperature, high-pressure liquid and flows out. The liquid refrigerant then flows through second evaporator solenoid valve 23 and battery pack solenoid valve 21, where it is throttled and depressurized by evaporator electronic expansion valve 15, transforming into a low-temperature, low-pressure gas-liquid two-phase flow. This gas-liquid two-phase flow then flows into evaporator 18 to cool the battery water circuit. After absorbing heat, the refrigerant becomes a sub-low-temperature, low-pressure gas, which then flows through second refrigeration solenoid valve 7 into gas-liquid separator 5. The sub-low-temperature, low-pressure gaseous refrigerant is then drawn back into compressor 1 and compressed into a high-temperature, high-pressure gaseous refrigerant.

[0245] In this mode, the speed of the compressor 1 is regulated according to the required cooling capacity of the battery pack 20 , and the opening of the evaporator electronic expansion valve 15 is regulated according to the superheat of the refrigerant at the outlet of the indoor heat exchanger 4 .

[0246] This solves the problem that traditional air source heat pumps cannot absorb heat from the ambient air under low temperature conditions and must add PTC for heating.

[0247] By using the circulating water system to play a role similar to that of a heat accumulator, the heat generated by the high-speed operation of the compressor is used as the main heat source for the heat pump under low-temperature conditions. Without adding additional components such as PTC and heat regenerators, it not only solves the problem of frosting of the heat pump, but also integrates the thermal management system of the battery pack and the passenger compartment, making the heat pump system more efficient, energy-saving, comfortable and economical.

[0248] Although the present disclosure is disclosed as above, the protection scope of the present disclosure is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present disclosure, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A thermal management method, characterized in that: A non-frost heat pump system for a hydrogen-powered vehicle without a PTC heater, the system comprising: A battery pack thermal management circulation system comprises a battery pack (20) which is fluidically connected end to end to form a battery pack thermal management circulation loop, a first inlet of an evaporator (18), a first outlet of the evaporator (18), a first inlet of a condenser (17), and a first outlet of the condenser (17), wherein the battery pack (20) is provided with a bypass line in parallel; and a water pump (19) is provided in the battery pack thermal management circulation loop; A passenger compartment thermal management circulation system comprises a compressor (1) constituting a heating circulation loop and a refrigeration circulation loop, an outdoor heat exchanger (2), an indoor heat exchanger (4), a refrigeration electronic expansion valve (3), a heating electronic expansion valve (8), an evaporator electronic expansion valve (15), the evaporator (18) and the condenser (17), wherein the refrigeration electronic expansion valve (3) is arranged between the outdoor heat exchanger (2) and the indoor heat exchanger (4) in the refrigeration circulation loop, and the heating electronic expansion valve (8) is arranged between the indoor heat exchanger (4) and the outdoor heat exchanger (2) in the heating circulation loop; The evaporator electronic expansion valve (15) is provided between the second outlet of the condenser (17) and the second inlet of the evaporator (18); The outlet of the compressor (1) is selectively connected to the inlet of the outdoor heat exchanger (2), the inlet of the indoor heat exchanger (4), and the second inlet of the condenser (17); The inlet of the compressor (1) is selectively connected to the second outlet of the evaporator (18), the outlet of the outdoor heat exchanger (2), and the outlet of the indoor heat exchanger (4); The outlet of the indoor heat exchanger (4) is selectively connected to the inlet of the outdoor heat exchanger (2), the second inlet of the condenser (17), and the second inlet of the evaporator (18); The inlet of the indoor heat exchanger (4) is selectively connected to the outlet of the outdoor heat exchanger (2) and the second outlet fluid of the condenser (17); The inlet of the outdoor heat exchanger (2) is fluidically connected to the second outlet of the condenser (17); The outlet of the outdoor heat exchanger (2) is fluidically connected to the second inlet of the evaporator (18); The refrigeration cycle loop comprises the compressor (1), the first refrigeration solenoid valve (6), the outdoor heat exchanger (2), the refrigeration electronic expansion valve (3), the indoor heat exchanger (4), the second refrigeration solenoid valve (7) and the gas-liquid separator (5) connected in sequence end to end; The heating circulation loop comprises the compressor (1), the first heating solenoid valve (9), the indoor heat exchanger (4), the heating electronic expansion valve (8), the outdoor heat exchanger (2), the second heating solenoid valve (10) and the gas-liquid separator (5) connected in sequence end to end; and / or, The outer surface of the compressor (1) is completely covered with a thermal insulation layer; A condenser solenoid valve (14) is provided between the compressor (1) and the second inlet of the condenser (17); the condenser (17) and the evaporator (18) are connected in series to form a first parallel branch, and the first parallel branch is connected in series with the gas-liquid separator (5) and the compressor (1); It also includes a first evaporation solenoid valve (22), an evaporator solenoid valve (16), the condenser (17), the evaporator electronic expansion valve (15), and the evaporator (18) which are fluidically connected in sequence to form a second parallel branch, wherein the second parallel branch is located after the indoor heat exchanger (4) in the heating cycle and is connected in series with the pipeline between the gas-liquid separator (5), and the outlet of the gas-liquid separator (5) is fluidically connected to the inlet of the compressor (1); The invention also includes a third parallel branch formed by fluidly connecting a second evaporation solenoid valve (23), a battery pack solenoid valve (21), the evaporator electronic expansion valve (15), and the evaporator (18) in sequence, wherein the third parallel branch is connected in series with a pipeline located after the outdoor heat exchanger (2) and between the gas-liquid separator (5) in the refrigeration cycle, and the outlet of the gas-liquid separator (5) is fluidly connected to the inlet of the compressor (1); and / or, It also includes a first three-way valve, which replaces the first cooling solenoid valve (6) and the first heating solenoid valve (9); or, It also includes a second three-way valve, which replaces the second heating solenoid valve (10); or, Also includes a third three-way valve, the third three-way valve replacing the second evaporation solenoid valve (23); or, The bypass pipeline and the input end of the battery pack (20) are respectively provided with a solenoid valve, or the input end of the battery pack (20) is provided with a fourth three-way valve, and the third outlet of the fourth three-way valve is fluidically connected to the bypass pipeline; The thermal management method comprises: Step S1: Acquire a passenger compartment thermal management mode; wherein the passenger compartment thermal management mode includes a passenger compartment heating mode, a passenger compartment cooling mode, and a passenger compartment no-demand mode; Step S2: Obtaining a battery pack thermal management mode; wherein the battery pack thermal management mode includes a battery pack no-demand mode, a battery pack average temperature mode, a battery pack heating mode, and a battery pack cooling mode; Step S3: controlling the on / off state of the pipelines formed by the compressor (1), the outdoor heat exchanger (2), the indoor heat exchanger (4), the cooling electronic expansion valve (3), the heating electronic expansion valve (8), the battery pack (20), the evaporator (18), the condenser (17), and the evaporator electronic expansion valve (15), and their respective operating states, so that the operation of the hydrogen energy vehicle heat pump system based on the PTC heater-free circulating water circuit satisfies the passenger compartment thermal management mode and the battery pack thermal management mode; When the passenger compartment thermal management mode is the passenger compartment heating mode and the battery pack thermal management mode is the battery pack temperature equalization mode, step S3 specifically includes: Step S301: controlling a portion of the high-temperature and high-pressure working fluid from the compressor (1) to flow through the indoor heat exchanger (4) to cool down and form a sub-high-temperature and high-pressure working fluid and achieve passenger compartment temperature increase; the remaining portion of the high-temperature and high-pressure working fluid from the compressor (1) to flow through the condenser (17) to cool down and form a sub-high-temperature and high-pressure working fluid; the sub-high-temperature and high-pressure working fluid flowing out of the indoor heat exchanger (4) is divided into two branches, the sub-high-temperature and high-pressure working fluid of one branch flows to the heating electronic expansion valve (8) to be throttled and depressurized to form a low-temperature and low-pressure working fluid, and then flows to the outdoor heat exchanger (2) to cool the ambient air to a temperature not lower than its dew point temperature, and is heated to form a sub-low temperature and low pressure working fluid, and then flows to the compressor (1); the sub-high temperature and high pressure working fluid of the other branch is mixed with the sub-high temperature and high pressure working fluid formed by cooling the condenser (17) through the first evaporation solenoid valve (22) and the battery pack solenoid valve (21), and then flows to the evaporator electronic expansion valve (15), is throttled and reduced in pressure, and then flows to the evaporator (18), is heated to form a low temperature and low pressure working fluid, and then flows to the compressor (1); the working fluid of the battery pack thermal management circulation loop is controlled to flow through the battery pack (20), the evaporator (18), and the condenser (17) in sequence under the action of the water pump (19); Step S302: regulating the opening of the heating electronic expansion valve (8) according to the ambient air being cooled to a temperature not lower than its dew point temperature and the superheat of the low-temperature and low-pressure working fluid exiting the outdoor heat exchanger (2); Step S303: regulating the speed of the compressor (1) according to the required heating amount of the passenger compartment heating mode and the heat provided by the ambient air; Step S304: regulating the flow rate of the sub-high temperature and high pressure working fluid flowing to the evaporator (18) and the opening of the evaporator electronic expansion valve (15) according to the opening of the heating electronic expansion valve (8) and the rotation speed of the compressor (1); Step S305: regulating the flow rate of the high-temperature and high-pressure working medium from the compressor (1) to the condenser (17) according to the superheat of the low-temperature and low-pressure working medium output from the evaporator (18) and the water inlet temperature of the battery pack.

2. The thermal management method according to claim 1, wherein: When the passenger compartment thermal management mode is the passenger compartment heating mode and the battery pack thermal management mode is the battery pack heating mode, step S3 specifically includes the following steps: S306: controlling a portion of the high-temperature and high-pressure working fluid from the compressor (1) to flow through the indoor heat exchanger (4) to cool down and form a sub-high-temperature and high-pressure working fluid, and realizing that the passenger compartment is heated up and then flows to the heating electronic expansion valve (8) to be throttled and depressurized to form a low-temperature and low-pressure working fluid, and then flows to the outdoor heat exchanger (2), cooling the ambient air to a temperature not lower than its dew point temperature, and heating it to form a sub-low-temperature and low-pressure working fluid, and then flows to the compressor (1); the remaining portion of the high-temperature and high-pressure working fluid from the compressor (1) flows through the condenser (17) to cool down and form a sub-high-temperature and high-pressure working fluid, and then flows to the evaporator electronic expansion valve (15) to be throttled and depressurized and then flows to the evaporator (18) to be heated to form a sub-low-temperature and low-pressure working fluid, and then flows to the compressor (1); controlling the working fluid of the battery pack thermal management circulation loop to flow through the battery pack (20), the evaporator (18) and the condenser (17) in sequence under the action of the water pump (19); S307: regulating the opening of the heating electronic expansion valve (8) according to the ambient air being cooled to a temperature not lower than its dew point temperature and the superheat of the low-temperature and low-pressure working fluid exiting the outdoor heat exchanger (2); S308: regulating the speed of the compressor (1) according to the required heating amount of the heating demand and the heat provided by the ambient air; S309: regulating the flow rate of the sub-high temperature and high pressure working fluid flowing to the evaporator (18) and the opening of the evaporator electronic expansion valve (15) according to the opening of the heating electronic expansion valve (8) and the rotation speed of the compressor (1); S310, regulating the flow of the high-temperature and high-pressure working medium to the condenser (17) according to the superheat of the sub-low-temperature and low-pressure working medium discharged from the evaporator (18) and the water inlet temperature of the battery pack; and / or, When the passenger compartment thermal management mode is the passenger compartment heating mode and the battery pack thermal management mode is the battery pack cooling mode, step S3 specifically includes the following steps: S311: Control the high-temperature and high-pressure working fluid discharged from the compressor (1) to flow through the indoor heat exchanger (4) to reduce the temperature to form a sub-high-temperature and high-pressure working fluid and realize the heating of the passenger compartment. A portion of the sub-high-temperature and high-pressure working fluid flows to the heating electronic expansion valve (8) to be throttled and reduced in pressure to form a low-temperature and low-pressure working fluid, and then flows to the outdoor heat exchanger (2) to cool the ambient air to a temperature not lower than its dew point temperature and heat it to form a sub-low-temperature and low-pressure working fluid, and then flows to the compressor (1). The remaining portion of the sub-high-temperature and high-pressure working fluid flows to the evaporator electronic expansion valve (15) to be throttled and reduced in pressure, and then flows to the evaporator (18) to heat it to form a sub-low-temperature and low-pressure working fluid, and then flows to the compressor (1); control the working fluid of the battery pack thermal management circulation loop to flow through the battery pack, the evaporator (18) and the condenser (17) in sequence under the action of the water pump (19); S312: regulating the opening of the heating electronic expansion valve (8) according to the ambient air being cooled to a temperature not lower than its dew point temperature and the superheat of the low-temperature and low-pressure working fluid discharged from the outdoor heat exchanger (2); S313: regulating the speed of the compressor (1) according to the required heating amount of the heating demand and the heat provided by the ambient air; S314: regulating the flow rate of the sub-high temperature and high pressure working fluid flowing to the evaporator (18) and the opening of the evaporator electronic expansion valve (15) according to the opening of the heating electronic expansion valve (8) and the rotation speed of the compressor (1); and / or, When the passenger compartment thermal management mode is the passenger compartment cooling mode and the battery pack thermal management mode is the battery pack cooling mode, step S3 specifically includes the following steps: S315: Control the high-temperature and high-pressure working fluid discharged from the compressor (1) to flow through the outdoor heat exchanger (2) to reduce the temperature and form a sub-high-temperature and high-pressure working fluid, a portion of the sub-high-temperature and high-pressure working fluid flows to the refrigeration electronic expansion valve (3) to be throttled and depressurized to form a low-temperature and low-pressure working fluid, and then flows to the indoor heat exchanger (4) to be heated to form a sub-low-temperature and low-pressure working fluid to achieve passenger compartment cooling, and then flows to the compressor (1), and the remaining portion of the sub-high-temperature and high-pressure working fluid flows to the evaporator electronic expansion valve (15) to be throttled and depressurized, and then flows to the evaporator (18) to be heated to form a sub-low-temperature and low-pressure working fluid, and then flows to the compressor (1); control the working fluid of the battery pack thermal management circulation loop to flow through the battery pack, the evaporator (18) and the condenser (17) in sequence under the action of the water pump (19); S316: regulating the rotation speed of the compressor (1), the opening of the refrigeration electronic expansion valve (3), and the opening of the evaporator electronic expansion valve (15) according to the required cooling capacity of the refrigeration demand and the required heat dissipation of the battery pack; and / or, When the passenger compartment thermal management mode is the passenger compartment cooling mode and the battery pack thermal management mode is the battery pack heating mode, step S3 specifically includes the following steps: S317: Control the high-temperature and high-pressure working fluid from the compressor (1) to flow to the condenser (17) to cool down and form a sub-high-temperature and high-pressure working fluid, a portion of the sub-high-temperature and high-pressure working fluid flows to the refrigeration electronic expansion valve (3) to be throttled and depressurized to form a low-temperature and low-pressure working fluid, and then flows to the indoor heat exchanger (4) to be heated to form a sub-low-temperature and low-pressure working fluid to achieve passenger compartment cooling, and then flows to the compressor (1), the remaining portion of the sub-high-temperature and high-pressure working fluid flows to the evaporator electronic expansion valve (15) to be throttled and depressurized, and then flows to the evaporator (18) to be heated to form a sub-low-temperature and low-pressure working fluid, and then flows to the compressor (1); control the working fluid of the battery pack thermal management circulation loop to flow through the battery pack, the evaporator (18), and the condenser (17) in sequence under the action of the water pump (19); S318: regulating the speed of the compressor, the opening of the refrigeration electronic expansion valve (3), and the opening of the evaporator electronic expansion valve (15) according to the required cooling capacity of the refrigeration demand and the required heating capacity of the battery pack; and / or, When the passenger compartment thermal management mode is the passenger compartment cooling mode and the battery pack thermal management mode is the battery pack temperature equalization mode, step S3 specifically includes the following steps: S319, controlling the high-temperature and high-pressure working fluid discharged from the compressor (1) to flow through the outdoor heat exchanger (2) to reduce the temperature to form a sub-high-temperature and high-pressure working fluid, then flowing to the refrigeration electronic expansion valve (3) to be throttled and reduced in pressure to form a low-temperature and low-pressure working fluid, then flowing to the indoor heat exchanger (4) to increase the temperature to form a sub-low-temperature and low-pressure working fluid to achieve passenger compartment cooling, and then flowing to the compressor (1); controlling the working fluid of the battery pack thermal management circulation loop to flow through the battery pack, the evaporator (18), and the condenser (17) in sequence under the action of the water pump (19); S320: regulating the speed of the compressor (1) according to the required cooling capacity of the cooling demand; S321: regulating the opening of the refrigeration electronic expansion valve (3) according to the superheat of the sub-low temperature and low pressure working medium output from the indoor heat exchanger (4); and / or, When the passenger compartment thermal management mode is the passenger compartment cooling mode and the battery pack thermal management mode is the battery pack no-demand mode, step S3 specifically includes the following steps: S322: Controlling the high-temperature and high-pressure working fluid discharged from the compressor (1) to flow through the outdoor heat exchanger (2) to reduce the temperature to form a sub-high-temperature and high-pressure working fluid, then flowing to the refrigeration electronic expansion valve (3) to be throttled and reduced in pressure to form a low-temperature and low-pressure working fluid, then flowing to the indoor heat exchanger (4) to increase the temperature to form a sub-low-temperature and low-pressure working fluid to achieve passenger cabin cooling, and then flowing to the compressor (1); S323: regulating the rotation speed of the compressor (1) according to the required cooling capacity of the passenger compartment cooling mode; S324: regulating the opening of the refrigeration electronic expansion valve (3) according to the superheat of the sub-low temperature and low pressure working medium output from the indoor heat exchanger (4); and / or, When the passenger compartment thermal management mode is the passenger compartment no-demand mode and the battery pack thermal management mode is the battery pack uniform temperature mode, step S3 specifically includes the following steps: S325: Controlling the working fluid of the battery pack thermal management circulation loop to flow sequentially through the battery pack (20), the evaporator (18), and the condenser (17) under the action of the water pump (19); and / or, When the passenger compartment thermal management mode is the passenger compartment no-demand mode and the battery pack thermal management mode is the battery pack heating mode, step S3 specifically includes the following steps: S326: Control the high-temperature and high-pressure working fluid from the compressor (1) to flow through the condenser (17) to cool down and form a sub-high-temperature and high-pressure working fluid, a portion of the sub-high-temperature and high-pressure working fluid flows to the heating electronic expansion valve (8) to be throttled and depressurized to form a low-temperature and low-pressure working fluid, and then flows to the outdoor heat exchanger (2) to cool the ambient air to a temperature not lower than its dew point temperature and heat it up to form a sub-low-temperature and low-pressure working fluid, and then flows to the compressor (1), the remaining portion of the sub-high-temperature and high-pressure working fluid flows to the evaporator electronic expansion valve (15) to be throttled and depressurized, and then flows to the evaporator (18) to heat it up to form a sub-low-temperature and low-pressure working fluid, and then flows to the compressor (1); control the working fluid of the battery pack thermal management circulation loop to flow through the battery pack, the evaporator (18) and the condenser (17) in sequence under the action of the water pump (19); S327: regulating the speed of the compressor (1), the opening of the heating electronic expansion valve (8), and the opening of the evaporator electronic expansion valve (15) according to the ambient air being cooled to a temperature not lower than its dew point temperature and the required heating amount of the battery pack; and / or, When the passenger compartment thermal management mode is the passenger compartment no-demand mode and the battery pack thermal management mode is the battery pack cooling mode, step S3 specifically includes the following steps: S328: Control the high-temperature and high-pressure working fluid discharged from the compressor (1) to flow through the outdoor heat exchanger (2) to reduce the temperature to form a sub-high-temperature and high-pressure working fluid, then flow to the evaporator electronic expansion valve (15) to be throttled and reduced in pressure to form a low-temperature and low-pressure working fluid, then flow to the evaporator (18) to increase the temperature to form a sub-low-temperature and low-pressure working fluid, and then flow to the compressor (1); control the working fluid of the battery pack thermal management circulation loop to flow through the battery pack, the evaporator (18), and the condenser (17) in sequence under the action of the water pump (19); S329: regulating the rotation speed of the compressor (1) according to the required cooling capacity of the battery pack; S330: regulating the opening of the evaporator electronic expansion valve (15) according to the superheat of the sub-high temperature and high pressure working fluid output from the evaporator (18).

3. The thermal management method according to claim 2, wherein: When the passenger compartment thermal management mode is the passenger compartment heating mode and the battery pack thermal management mode is the battery pack no-demand mode, step S3 specifically includes the following steps: S331: Control the high-temperature and high-pressure working fluid discharged from the compressor (1) to flow through the indoor heat exchanger (4) to cool down to form a sub-high-temperature and high-pressure working fluid and achieve passenger compartment temperature increase; a portion of the sub-high-temperature and high-pressure working fluid flows to the heating electronic expansion valve (8) to be throttled and depressurized to form a low-temperature and low-pressure working fluid, and then flows to the outdoor heat exchanger (2) to cool the ambient air to a temperature not lower than its dew point temperature and heat it up to form a sub-low-temperature and low-pressure working fluid, and then flows to the compressor; the remaining portion of the sub-high-temperature and high-pressure working fluid flows to the condenser (17) to cool down, and then throttled and depressurized by the evaporator electronic expansion valve (15), and then flows to the evaporator (18) to heat up to form a sub-low-temperature and low-pressure working fluid, and then flows to the compressor (1); control the working fluid of the battery pack thermal management circulation loop to flow through the bypass pipe, the evaporator (18) and the condenser (17) in sequence under the action of the water pump (19); S332: regulating the opening of the heating electronic expansion valve (8) according to the ambient air being cooled to a temperature not lower than its dew point temperature and the superheat of the low-temperature and low-pressure working fluid output from the outdoor heat exchanger (2); S333: regulating the speed of the compressor (1) according to the required heating amount of the heating demand and the heat provided by the ambient air; S334: regulating the flow rate of the sub-high temperature and high pressure working fluid flowing to the evaporator (18) and the opening of the evaporator electronic expansion valve (15) according to the opening of the heating electronic expansion valve (8) and the rotation speed of the compressor (1).

4. The thermal management method according to claim 3, characterized in that: Also includes the steps: S335: determining whether the superheat of the working fluid discharged from the evaporator (18) is lower than a preset value; When the superheat of the working fluid discharged from the evaporator (18) is lower than a preset value, the battery pack thermal management mode is switched from the battery pack no-demand mode to the battery pack uniform temperature mode, and steps S301 to S305 are executed until the water temperature of the battery pack thermal management circulation loop reaches a maximum temperature threshold value not lower than the battery pack no-demand mode, and the battery pack thermal management mode is switched from the battery pack uniform temperature mode to the battery pack no-demand mode, and steps S331 to S334 are executed; otherwise, the battery pack thermal management mode is maintained as the battery pack uniform temperature mode and steps S301 to S305 are executed.

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