Phase-change liquid-cooled energy storage heat-moisture separation refrigeration system and control method

Abstract

The present invention provides a phase-change liquid-cooled energy storage heat and moisture separation refrigeration system and control method, which belongs to the field of chemical liquid-cooled battery energy storage technology, wherein the phase-change liquid-cooled energy storage heat and moisture separation refrigeration system includes a battery cabinet, an air cooling system and an in-cabinet liquid cooling system; the air cooling system includes a fan assembly, the fan assembly includes a fan, an air-cooled evaporator, and an electric heater; the air outlet temperature of the fan assembly is higher than the air dew point temperature in the cabinet; the in-cabinet liquid cooling system is connected to a low-pressure circulation barrel by means of a liquid supply pipeline and a return air pipeline; the in-cabinet liquid cooling system includes a first circulation pipeline and a second circulation pipeline; the second circulation pipeline includes a second liquid supply pipe connecting the liquid supply pipeline and the inlet end of the air-cooled evaporator, and a second return air pipe connecting the outlet end of the air-cooled evaporator and the return air pipeline. The phase-change liquid-cooled energy storage heat and moisture separation refrigeration system provided by the present invention avoids the precipitation of condensed water from the air after being cooled by making the actual temperature of the air in the cabinet higher than its dew point temperature.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical liquid-cooled battery energy storage, and more specifically, relates to a phase-change liquid-cooled energy storage heat-moisture separation refrigeration system and a control method. Background Art

[0002] In the field of battery energy storage, liquid cooling structures are usually used to increase system energy density, improve heat dissipation efficiency, and reduce the temperature difference of battery cells. With the introduction of liquid cooling structures, the battery protection level has been greatly improved. Battery cabinets are usually sealed boxes, which limits the airflow exchange between the battery cabinet and the external environment.

[0003] If the air temperature in the cabinet is high and the temperature of the liquid cooling plate is low, the high temperature air will easily condense into condensed water after contacting the liquid cooling plate, and the battery module casing in the cabinet will easily form a short circuit through the condensed water, resulting in poor safety and reliability. Summary of the invention

[0004] The purpose of the present invention is to provide a phase-change liquid-cooled energy storage heat and moisture separation refrigeration system and a control method, aiming to solve the problem that liquid-cooled heat exchange is prone to produce condensed water.

[0005] To achieve the above object, the technical solution adopted by the present invention is: to provide a phase-change liquid-cooled energy storage heat and moisture separation refrigeration system, comprising:

[0006] A battery cabinet, wherein a plurality of battery modules are provided in the battery cabinet; a low-pressure circulation barrel containing a refrigerant is arranged outside the battery cabinet;

[0007] An air cooling system, comprising a fan assembly arranged at the bottom of the inner cavity of the battery cabinet, wherein the fan assembly comprises a fan, an air-cooled evaporator, and an electric heater arranged in sequence from front to back, and the gaps between the battery module and the front and rear walls of the battery cabinet and the gaps between adjacent battery modules are interconnected to form a circulating cooling air duct; the air outlet temperature of the fan assembly is higher than the dew point temperature of the air in the battery cabinet;

[0008] The in-cabinet liquid cooling system is connected to the low-pressure circulation barrel by means of a liquid supply pipeline and an air return pipeline; the in-cabinet liquid cooling system includes a first circulation pipeline and a second circulation pipeline; the first circulation pipeline includes a first liquid supply pipe connecting the liquid supply pipeline and the refrigerant inlet of the battery module, and a first air return pipe connecting the air return pipeline and the refrigerant outlet of the battery module; the second circulation pipeline includes a second liquid supply pipe connecting the liquid supply pipeline and the inlet end of the air-cooled evaporator, and a second air return pipe connecting the outlet end of the air-cooled evaporator and the return air pipeline.

[0009] As another embodiment of the present application, an air uniforming plate is installed at the rear of the battery cabinet, and the air uniforming plate divides the battery cabinet into a rear air duct for connecting to the fan assembly and an installation space for installing the battery module, and the installation space is located in front of the rear air duct; the air uniforming plate is provided with a plurality of ventilation holes connecting the rear air duct and the installation space.

[0010] As another embodiment of the present application, a plurality of the battery modules are longitudinally arranged at equal intervals in the installation space; a front air duct is provided between the front end of the battery module and the front side wall of the battery cabinet, and a horizontal air duct is formed by the gap between adjacent battery modules; the horizontal air duct connects the rear air duct and the front air duct.

[0011] As another embodiment of the present application, a condensate collecting tray is disposed at the lower portion of the fan assembly, and a condensate drain hose is disposed at the lower end of the condensate collecting tray.

[0012] As another embodiment of the present application, a plurality of first liquid supply pipes on the same liquid supply pipeline are arranged in parallel.

[0013] As another embodiment of the present application, it also includes:

[0014] The external liquid cooling system includes a compressor, a condenser, a main expansion valve and the low-pressure circulation barrel; an oil separator is arranged between the compressor and the condenser, and an oil return pipeline is arranged at the lower end of the oil separator. The lubricating oil in the refrigerant enters the oil return pipeline from the oil separator and passes through the oil cooler, the oil return capillary and the oil return solenoid valve in sequence before re-entering the compressor; the temperature of the refrigerant in the low-pressure circulation barrel is higher than the dew point temperature of the air in the battery cabinet.

[0015] As another embodiment of the present application, the exhaust pipe on the low-pressure circulation barrel is connected to the compressor, and an auxiliary oil return pipe is also provided in the low-pressure circulation barrel, one end of the auxiliary oil return pipe is located inside the low-pressure circulation barrel, and the upper end of the auxiliary oil return pipe passes through the low-pressure circulation barrel and is connected to the exhaust pipe by means of an oil return nozzle; the auxiliary oil return pipe is provided with a regulating hand valve and an oil return sight glass.

[0016] As another embodiment of the present application, an auxiliary cooling circuit is further provided between the condenser and the main expansion valve, and the auxiliary cooling circuit is connected to the oil cooler for cooling the high-temperature and high-pressure lubricating oil in the oil cooler.

[0017] The beneficial effects of the phase-change liquid-cooled energy storage heat and moisture separation refrigeration system provided by the present invention are as follows: compared with the prior art, the phase-change liquid-cooled energy storage heat and moisture separation refrigeration system of the present invention arranges an air cooling system and an in-cabinet liquid cooling system in the battery cabinet, and the in-cabinet liquid cooling system not only cools the battery module but also cools the air in the air cooling system; the air temperature in the cabinet is lowered by the air cooling system and the in-cabinet liquid cooling system, and the temperature difference between the air in the cabinet and the battery module is reduced. By making the actual temperature of the air in the battery cabinet higher than its dew point temperature, the condensation of condensed water from the air in the cabinet after being cooled is avoided.

[0018] A control system for a phase-change liquid-cooled energy storage heat and moisture separation refrigeration system is also provided, comprising the following steps:

[0019] S1. After the battery is started, the liquid cooling system inside the cabinet is turned off and the liquid cooling system outside the cabinet is turned on;

[0020] S2. When the liquid level in the low-pressure circulation barrel is higher than the low liquid level and the temperature in the cabinet is higher than the set value, the second circulation pipeline and air cooling system of the liquid cooling system in the cabinet are turned on; the air outlet temperature of the fan assembly is higher than the dew point temperature in the cabinet;

[0021] S3. When the temperature of the battery module is higher than the set value, the first circulation pipeline of the liquid cooling system in the cabinet is opened;

[0022] S4. When the dew point temperature in the cabinet drops, adjust the flow rate of the second circulation pipeline of the air cooling system or the working efficiency of the electric heater at any time.

[0023] As another embodiment of the present application, in step S1, before the battery is started, if the temperature inside the cabinet is lower than the starting set value, the fan and electric heater of the blower assembly need to be turned on until the internal ambient temperature of the battery cabinet reaches the safe operating ambient temperature of the battery.

[0024] The beneficial effects of the control method of the phase-change liquid-cooled energy storage heat and moisture separation refrigeration system provided by the present invention are as follows: compared with the prior art, the control method of the phase-change liquid-cooled energy storage heat and moisture separation refrigeration system of the present invention realizes the cooling of the battery module and the air inside the cabinet by controlling the start-up and adjustment of the air cooling system, the liquid cooling system inside the cabinet and the liquid cooling system outside the cabinet; the temperature of the air inside the cabinet is lowered by the air cooling system and the liquid cooling system inside the cabinet, and the temperature difference between the air inside the cabinet and the battery module is reduced. By making the actual temperature of the air inside the battery cabinet higher than its dew point temperature, the condensation of condensed water from the air inside the cabinet after being cooled is avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A schematic diagram of the structure of a phase-change liquid-cooled energy storage heat and moisture separation refrigeration system provided in an embodiment of the present invention;

[0027] Figure 2 A schematic structural diagram of an air cooling system provided in an embodiment of the present invention.

[0028] In the figure: 1. Central control unit; 2. Compressor; 3. Oil separator; 4. Oil level switch; 5. Phase change refrigeration control unit; 6. Condensing fan; 7. Condenser; 8. Liquid storage tank; 9. Dry filter; 10. Main expansion valve; 11. Oil return regulating valve; 12. Low pressure circulation barrel; 13. High liquid level switch; 14. Low liquid level switch; 15. Refrigerant pump; 16. Pump outlet check valve; 17. Oil return sight glass; 18. Oil return nozzle; 19. Liquid supply pipeline; 20. Air return pipeline; 21. Bypass electronic expansion valve; 22. Oil cooler; 23. Oil return capillary; 24. Oil return solenoid valve; 25 , battery cabinet; 26, battery cabinet temperature control unit; 27, battery module; 28, first flow regulating valve; 29, main liquid supply hose; 30, first liquid supply pipe; 31, second liquid supply pipe; 32, second flow regulating valve; 33, auxiliary expansion valve; 34, auxiliary liquid supply hose; 35, fan; 36, fan assembly; 37, auxiliary return air hose; 38, first return air pipe; 39, second return air pipe; 40, temperature and humidity sensor; 41, main return air hose; 42, return air check valve; 43, air-cooled evaporator; 44, condensate drain hose; 45, condensate collection tray; 46, electric heater; 47, wind uniformity plate. DETAILED DESCRIPTION

[0029] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0030] See also Figure 1 to Figure 2, the phase-change liquid-cooled energy storage heat and moisture separation refrigeration system and control method provided by the present invention are now described. The phase-change liquid-cooled energy storage heat and moisture separation refrigeration system includes a battery cabinet 25, an air cooling system and an in-cabinet liquid cooling system; the battery cabinet 25 has a plurality of battery modules 27; a low-pressure circulation barrel 12 containing refrigerant is arranged on the outside of the battery cabinet 25; the air cooling system includes a fan assembly 36 arranged at the bottom of the inner cavity of the battery cabinet 25, and the fan assembly 36 includes a fan 35, an air-cooled evaporator 43, and an electric heater 46 arranged in sequence from front to back. The gaps between the battery module 27 and the front and rear walls of the battery cabinet 25 and the gaps between adjacent battery modules 27 are interconnected to form a circulating cooling air duct; the air outlet temperature of the fan assembly 36 is high The dew point temperature of the air in the battery cabinet 25; the liquid cooling system in the cabinet is connected to the low-pressure circulation barrel 12 by means of the liquid supply pipeline 19 and the return air pipeline 20; the liquid cooling system in the cabinet includes a first circulation pipeline and a second circulation pipeline; the first circulation pipeline includes a first liquid supply pipe 30 connecting the liquid supply pipeline 19 and the refrigerant inlet of the battery module 27, and a first return air pipe 38 connecting the return air pipeline 20 and the refrigerant outlet of the battery module 27; the second circulation pipeline includes a second liquid supply pipe 31 connecting the liquid supply pipeline 19 and the inlet end of the air-cooled evaporator 43, and a second return air pipe 39 connecting the outlet end of the air-cooled evaporator 43 and the return air pipeline 20.

[0031] Compared with the prior art, the phase-change liquid-cooled energy storage heat and moisture separation refrigeration system provided by the present invention is provided with an air cooling system and an in-cabinet liquid cooling system in the battery cabinet 25; when the battery module 27 is working, the air cooling system or the in-cabinet liquid cooling system or both are started at the same time; the battery module 27 in the battery cabinet 25 is cooled.

[0032] The air cooling system includes a fan assembly 36 arranged at the lower end of the inner cavity of the battery cabinet 25, wherein the fan assembly 36 includes a fan 35, an air-cooled evaporator 43 and an electric heater 46 arranged in sequence from front to back; under the action of the fan, the air in the cabinet passes through the gap between the battery module 27 and the rear wall of the battery cabinet 25, the gap between the battery modules 27, and the gap between the battery modules 27 and the front wall of the battery cabinet 25, and finally returns to the fan, forming a complete circulating cooling air duct to complete the air cooling cycle.

[0033] The liquid cooling system in the cabinet includes a first circulation pipeline for cooling the battery module 27 and a second circulation pipeline for cooling the air-cooled evaporator 43 in the fan assembly 36. The low-temperature refrigerant in the low-pressure circulation barrel 12 enters the cabinet from the liquid supply pipeline 19, a part of the refrigerant enters the first liquid supply pipe 30 and enters the battery module 27 through the first liquid supply pipe 30, the liquid refrigerant and the battery module 27 are heat exchanged to form a gaseous refrigerant, the gaseous refrigerant is transported from the first return air pipe 38 to the return air pipeline 20, and then transported to the low-temperature circulation barrel by the return air pipeline 20; the other part of the refrigerant enters the second liquid supply pipe 31 and enters the air-cooled evaporator 43 of the fan assembly 36 through the second liquid supply pipe 31, the liquid refrigerant and the air-cooled evaporator 43 are heat exchanged to form a gaseous refrigerant, the gaseous refrigerant is transported from the second return air pipe 39 to the return air pipeline 20 and mixed with the gaseous refrigerant transported by the first return air pipe 38. The second return air pipe 39 is connected to the upper part of the first return air pipe 38 , and a return air check valve 42 is also provided above the connection point; the mixed gaseous refrigerant needs to enter the return air pipeline 20 through the return air check valve 42 .

[0034] The phase-change liquid-cooled energy storage heat and moisture separation refrigeration system provided by the present invention has an air cooling system and an in-cabinet liquid cooling system arranged in the battery cabinet 25. The in-cabinet liquid cooling system not only cools the battery module 27 but also cools the air in the air cooling system. The air temperature in the cabinet is lowered by the air cooling system and the in-cabinet liquid cooling system, thereby reducing the temperature difference between the air in the cabinet and the battery module 27. By making the actual temperature of the air in the battery cabinet 25 higher than its dew point temperature, the condensation of condensed water from the air in the cabinet after being cooled is avoided.

[0035] Optionally, the battery module 27 includes a liquid cooling base plate, a module housing, and a battery cell; the module housing is fixed on the liquid cooling base plate to form a drawer structure, and the battery cell is located inside the drawer structure. A cooling inlet and a cooling outlet are provided on the liquid cooling base plate, and a curved working fluid flow channel is provided inside the liquid cooling base plate. The refrigerant enters the working fluid flow channel inside the liquid cooling base plate from the cooling inlet and flows along the working fluid flow channel to the cooling outlet; the refrigerant in the working fluid flow channel exchanges heat with the battery cell with the help of the liquid cooling base plate.

[0036] In another embodiment, the battery cabinet 25 is an immersed liquid-cooled battery cabinet 25, and the battery cabinet 25 includes a plurality of battery modules 27. The battery module 27 includes a module box filled with a temperature-adjusting insulating liquid and a battery cell located in the battery box and immersed in the temperature-adjusting insulating liquid. A refrigeration inlet and a refrigeration outlet are provided on the module box. The refrigerant enters the module box from the refrigeration inlet and is discharged from the refrigeration outlet. The refrigerant immerses the battery cell in the module box and exchanges heat with the battery cell during the flow process.

[0037] Optionally, the refrigerant needs to be non-conductive, non-secondary-polluting, clean, low-toxic, with good electrical insulation and high fire-extinguishing efficiency, such as heptafluoropropane.

[0038] Optionally, when the dew point temperature in the battery cabinet 25 drops, the air cooling system can be started at any time to cool and dehumidify the air in the cabinet and combined with the electric heater 46 to ensure that there is no risk of condensation water in the battery cabinet 25 modules and the space where the modules are located.

[0039] In some possible embodiments, see Figure 2 A wind uniforming plate 47 is installed at the rear of the battery cabinet 25, and the wind uniforming plate 47 divides the battery cabinet 25 into a rear air duct for connecting the fan assembly 36 and an installation space for installing the battery module 27, and the installation space is located in front of the rear air duct; the wind uniforming plate 47 is provided with a plurality of ventilation holes connecting the rear air duct and the installation space.

[0040] The rear of the battery cabinet 25 is provided with an air leveling plate 47, the upper end of the air leveling plate 47 is connected to the top plate of the battery cabinet 25, the side of the air leveling plate 47 is connected to the side plate of the battery cabinet 25, and the bottom plate of the air leveling plate 47 is connected to the upper end of the fan assembly 36. The air leveling plate 47 divides the inner cavity of the battery cabinet 25 into a front installation space and a rear air duct at the rear, wherein the installation space is used to install multiple battery modules 27, and the rear air duct is a gap between the air leveling plate 47 and the rear wall of the battery cabinet 25 for air circulation.

[0041] A plurality of ventilation holes are provided on the air-distributing plate 47, and the ventilation holes connect the rear passage and the installation space. Air enters the rear passage under the action of the fan assembly 36, and enters the installation space through the ventilation holes on the air-distributing plate 47, so that the air enters the rear of the battery module 27 evenly.

[0042] Multiple battery modules 27 are arranged at longitudinal intervals in the installation space, and there are gaps between adjacent battery modules 27, between the battery module 27 and the upper end plate of the fan assembly 36, and between the battery module 27 and the top plate of the battery cabinet 25; the above gaps are all flow channels connecting the front and rear of the battery module 27; the air entering the rear of the battery module 27 passes through the above flow channels from back to front, and at the same time there is partial heat exchange with the battery module 27, thereby achieving the effect of reducing the temperature of the battery module 27.

[0043] There is a front air duct between the front end of the battery module 27 and the front wall of the battery cabinet 25, and the front air duct is connected to the above-mentioned circulation channel and is also connected to the fan assembly 36 at the lower end; after exchanging heat with the battery module 27, the air enters the front air duct from the circulation channel, and enters the fan assembly 36 after being mixed in the front air duct, completing the air cooling cycle.

[0044] Optionally, a limiting partition is installed at the bottom of the battery cabinet 25, and the rear end of the limiting partition is connected to the wind uniforming plate 47; the bottom of the limiting partition is used to install the fan assembly 36 and form a lower channel; the top of the limiting partition, the wind uniforming plate 47 and the side wall of the battery cabinet 25 form an installation space.

[0045] Optionally, the limiting partition and the battery module 27 are spaced apart.

[0046] In some possible embodiments, see Figure 2 The fan assembly 36 includes a mounting frame and a fan 35, an air-cooled evaporator 43 and an electric heater 46 which are arranged on the mounting frame from front to back in sequence; wherein the mounting frame is fixed on the cabinet body of the battery cabinet 25 or on the above-mentioned limiting partition. The mounting frame is provided with a fan 35, and the blowing direction of the fan 35 is from front to back; the air outlet of the fan 35 is provided with an air-cooled evaporator 43, and the air-cooled evaporator 43 is provided with a plurality of fins extending outward to increase the heat exchange area; an electric heater 46 is also provided on the other side of the air-cooled evaporator 43, and the electric heater 46 adjusts the air temperature so that the temperature of the air entering the battery cabinet 25 is higher than the dew point temperature of the battery cabinet 25, thereby avoiding the condensation of water in the air.

[0047] Since the surface temperature of the air-cooled evaporator 43 is relatively low, condensation water is likely to occur when the air passes through the air-cooled evaporator 43, so a condensation water collecting pan 45 is provided below the air-cooled evaporator 43. The water condensed on the air-cooled evaporator 43 will flow downward into the condensation water collecting pan 45 and be discharged from the battery cabinet 25 through the condensation water drain hose 44.

[0048] When the battery module 27 is in normal operation, the air-cooled evaporator 43 at the bottom of the battery cabinet 25 cooperates with the fan to make the internal air of the battery cabinet 25 flow along the circulating cooling air duct, radiating heat from the battery module 27 and absorbing external heat through the battery cabinet 25, thereby ensuring the ambient temperature inside the cabinet.

[0049] In some possible embodiments, see Figure 1 and Figure 2, the air-cooled evaporator 43 is connected to the second liquid supply pipe 31 of the liquid cooling system in the cabinet. The low-temperature and low-pressure liquid refrigerant in the low-pressure circulation barrel 12 enters the second liquid supply pipe 31 through the liquid supply pipe 19, and is transported to the lower end of the battery cabinet 25 by the second liquid supply pipe 31; the second liquid supply pipe 31 is connected to the inlet end of the air-cooled evaporator 43 by means of the auxiliary liquid supply hose 34, and the second return air pipe 39 is connected to the outlet end of the air-cooled evaporator 43 by means of the auxiliary return air hose 37; so that the air-cooled evaporator 43 becomes a cold source in the air-cooling system. The second return air pipe 39 is connected to the return air pipe 20 to transport the gaseous refrigerant back to the low-pressure circulation barrel 12. The second flow regulating valve 32 and the auxiliary expansion valve 33 are arranged on the second liquid supply pipe 31. The second flow regulating valve 32 is used to adjust the flow in the second liquid supply pipe 31; the auxiliary expansion valve 33 is used to convert the low-temperature and low-pressure liquid refrigerant in the second liquid supply pipe 31 into a liquid refrigerant with a lower temperature and lower pressure.

[0050] At the same time, the first liquid supply pipe 30 connected to the liquid supply pipe 19 transports another part of the refrigerant into the refrigerant inlet of the battery module 27; after heat exchange in the battery module 27, the liquid refrigerant enters the first return air pipe 38 from its refrigerant outlet, and enters the return air pipe 20 with the help of the first return air pipe 38.

[0051] Since each battery cabinet 25 is provided with a plurality of battery modules 27, each battery module 27 is connected to the first liquid supply pipe 30 and the first air return pipe 38 respectively by means of the main liquid supply hose 29 and the main air return hose 41; therefore, the liquid cooling systems of each battery module 27 in the same battery cabinet 25 are connected in parallel.

[0052] Each battery cabinet 25 is an independent unit, and the liquid cooling systems corresponding to the battery cabinets 25 are connected in parallel. Each battery cabinet 25 corresponds to a first liquid supply pipe 30 and a first air return pipe 38. When a battery cabinet 25 is to be maintained, only the first liquid supply pipe 30 corresponding to the battery cabinet 25 needs to be closed.

[0053] Optionally, a first flow regulating valve 28 is disposed on the upper portion of the first liquid supply pipe 30, and a second flow regulating valve 32 and an auxiliary expansion valve 33 are disposed on the second liquid supply pipe 31. The upper end of the second liquid supply pipe 31 is connected to the liquid supply pipeline 19 or the upper end of the first liquid supply pipe 30, that is, the upper end of the second liquid supply pipe 31 is located above the first flow regulating valve 28.

[0054] In some possible embodiments, see Figure 1The phase-change liquid-cooled energy storage heat and moisture separation refrigeration system also includes an external liquid cooling system, which includes a compressor 2, a condenser 7, a main expansion valve 10, and a low-pressure circulation barrel 12; an oil separator 3 is provided between the compressor 2 and the condenser 7, and an oil return pipeline is provided at the lower end of the oil separator 3. The lubricating oil in the refrigerant enters the oil return pipeline from the oil separator 3 and passes through the oil cooler 22, the oil return capillary 23, and the oil return solenoid valve 24 in sequence before re-entering the compressor 2; the temperature of the refrigerant in the low-pressure circulation barrel 12 is higher than the dew point temperature of the air in the battery cabinet 25. Since the temperature of the liquid refrigerant entering the battery module 27 is controlled to be higher than the dew point temperature in the cabinet, the full sensible heat exchange inside the battery module 27 is guaranteed, thereby ensuring the safety of the equipment.

[0055] The compressor 2 compresses the refrigerant so that the low-temperature and low-pressure liquid refrigerant is converted into a high-temperature and high-pressure gaseous refrigerant. The high-temperature and high-pressure gaseous refrigerant enters the oil separator 3. After the lubricating oil of the compressor 2 is filtered out in the oil separator 3, the high-temperature and high-pressure gaseous refrigerant enters the condenser 7 again. The high-temperature and high-pressure gaseous refrigerant is heat-exchanged with the low-temperature air by the external wind power provided by the condensing fan 6 in the condenser 7. After the heat exchange, it becomes a medium-temperature and high-pressure liquid refrigerant. The medium-temperature and high-pressure liquid refrigerant enters the drying filter 9. The water and impurities contained in the medium-temperature and high-pressure liquid refrigerant in the drying filter 9 are adsorbed. The medium-temperature and high-pressure liquid refrigerant flows through the main expansion valve 10 again. After being throttled by the main expansion valve 10, it becomes a low-temperature and low-pressure liquid refrigerant and is transported to the low-pressure circulation barrel 12 and settles to the lower part of the low-pressure circulation barrel 12. Optionally, the condensing fan 6 uses a variable frequency fan. The condensing fan 6 is controlled by the pressure measured by the pressure sensor in front of it. As the pressure increases, the fan frequency increases. Optionally, a liquid reservoir 8 is further provided between the condenser 7 and the drying filter 9 .

[0056] The refrigerant pump 15 provides circulation power to sink the low-temperature and low-pressure liquid refrigerant at the bottom of the low-pressure circulation barrel 12 to the bottom of the low-pressure circulation barrel 12 for full utilization. After evaporation, the low-pressure and low-temperature gaseous refrigerant flows through the oil return nozzle 18 and enters the compressor 2 for circulation. The outlet end of the refrigerant pump 15 is provided with a pump outlet check valve 16;

[0057] An oil return pipeline is provided at the lower part of the oil separator 3. The high-temperature and high-pressure lubricating oil enters the oil cooler 22 from the oil separator 3, exchanges heat with the refrigerant in the oil cooler 22 to become low-temperature and high-pressure lubricating oil, and then becomes low-temperature and low-pressure lubricating oil after flowing through the oil return capillary 23. After passing through the oil return solenoid valve 24, it is mixed with the low-temperature and low-pressure refrigerant gas and then enters the suction port of the compressor 2 to complete the oil separation and oil return.

[0058] An auxiliary cooling circuit is led out between the condenser 7 and the main expansion valve 10 , and the auxiliary cooling circuit is connected to the oil cooler 22 for cooling the high-temperature and high-pressure lubricating oil in the oil cooler 22 .

[0059] The medium-temperature and high-pressure liquid refrigerant at the outlet of the drying filter 9 flows through the bypass electronic expansion valve 21, and after being throttled by the bypass electronic expansion valve 21, it becomes a low-temperature and low-pressure liquid refrigerant and is transported to the oil cooler 22 for heat exchange with the high-temperature lubricating oil. The liquid refrigerant absorbs heat and evaporates to become a low-temperature and low-pressure gaseous refrigerant, and then mixes with the gaseous refrigerant from the main low-pressure circulation barrel 12 back to the compressor 2 and enters the compressor 2 together.

[0060] An oil level switch 4 is provided in the oil separator 3. When the oil level in the oil separator 3 is higher than the oil level switch 4, the solenoid valve is opened to return the oil. When the oil outlet temperature sensor of the oil cooler measures that the oil temperature is higher than the set value, the auxiliary expansion valve 33 on the auxiliary cooling circuit is opened and adjusted to open and control the oil temperature.

[0061] Because the oil separator 3 cannot filter 100% of the lubricating oil, a small amount of lubricating oil will be transported to the low-pressure circulation barrel 12 when circulating in the system. The lubricating oil is a liquid that cannot effectively flow back to the compressor 2 with the refrigerant gas. Therefore, an auxiliary oil return pipe is also connected to the exhaust pipe set at the upper end of the low-pressure circulation. One end of the auxiliary oil return pipe is located inside the low-pressure circulation barrel 12. The upper end of the auxiliary oil return pipe penetrates the low-pressure circulation barrel 12 and is connected to the exhaust pipe by means of an oil return nozzle 18; the auxiliary oil return pipe is provided with a regulating hand valve and an oil return sight glass 17. When returning the oil, a small portion of the refrigerant liquid rich in lubricating oil is directly transported to the exhaust pipe through the oil return regulating hand valve 11 and the oil return sight glass 17 by using the principle of negative pressure of the nozzle, and the exhaust pipe transports this part of the lubricating oil to the compressor 2.

[0062] Different oil return holes are arranged on the height gradient of the oil return pipeline inside the low-pressure circulation barrel 12. The oil return regulating hand valve 11 is adjusted by observing the state of the lubricating oil in the oil return sight glass 17 to ensure sufficient oil return of the lubricating oil.

[0063] A low liquid level switch 14 and a high liquid level switch 13 are provided in the low-pressure circulation barrel 12; the return oil pipe extends below the low liquid level switch 14, and a plurality of return oil holes are provided at intervals between the low liquid level switch 14 and the high liquid level switch 13 to ensure that the mixed state of the refrigerant and the lubricating oil can be recovered under the operating state.

[0064] Optionally, three oil return holes are provided, and the three oil return holes are spaced apart along the height direction of the oil return pipe. The bottom oil return hole is flush with the low liquid level switch 14, and the top oil return hole is flush with the high liquid level switch 13. The spacing between two adjacent oil return holes is consistent.

[0065] The oil return pipe section is U-shaped, and includes a first longitudinal pipe section, a transverse pipe section and a second longitudinal pipe section connected in sequence; the lower end of the second longitudinal pipe section is located at the lower part of the circulation barrel body, and the open end of the second longitudinal pipe section is located at the upper part of the circulation barrel body; the oil return hole is opened on the side wall of the second longitudinal pipe section.

[0066] The first longitudinal pipe section, the transverse pipe section and the second longitudinal pipe section are connected in sequence to form a U-shaped internal oil return pipe, wherein the height of the second longitudinal pipe section is less than that of the first longitudinal pipe section. The transverse pipe section is arranged horizontally and is located below the low liquid level switch 14. The oil return hole is opened on the second longitudinal pipe section to reduce the fluctuation of the oil return hole and the liquid level inside the circulation barrel body when the first longitudinal pipe section returns oil.

[0067] See also Figure 1 and Figure 2 The control method based on the above-mentioned phase change liquid cooling energy storage heat and moisture separation refrigeration system includes the following steps:

[0068] S1. After the battery is started, the liquid cooling system inside the cabinet is turned off and the liquid cooling system outside the cabinet is turned on;

[0069] S2, when the liquid level in the low-pressure circulation barrel 12 is higher than the low liquid level switch 14 and the temperature in the cabinet is higher than the set value, the second circulation pipeline and the air cooling system of the liquid cooling system in the cabinet are turned on; the air outlet temperature of the fan assembly 36 is higher than the dew point temperature in the cabinet;

[0070] S3. When the temperature of the battery module 27 is higher than the set value, the first circulation pipeline of the liquid cooling system in the cabinet is opened;

[0071] S4. When the dew point temperature in the cabinet decreases, the flow rate of the second circulation pipeline of the air cooling system or the working efficiency of the electric heater 46 is adjusted at any time.

[0072] Specifically, after the battery is started, the control unit receives the battery start-up working signal, turns off all the liquid cooling systems in the cabinet, and turns on the liquid cooling system in the cabinet. The compressor 2 starts to cool until the liquid level in the low-pressure circulation barrel 12 is higher than the low liquid level switch 14 and the temperature in the battery cabinet 25 is higher than the set value, then turns on the air cooling system and the second circulation pipeline, and circulates and exchanges heat with the air in the battery cabinet 25 through the air cooling system; the battery module 27 in the battery cabinet 25 and the air in the battery cabinet 25 are cooled. Optionally, the refrigerant temperature in the low-pressure circulation barrel 12 is required to be higher than the dew point temperature of the air in the cabinet, but when the humidity of the battery cabinet 25 is lower than the set value and the dew point temperature is higher than the liquid temperature in the low-pressure circulation barrel 12, the battery module 27 is allowed to work.

[0073] On the basis of the air cooling system being turned on, when the temperature of the battery module 27 is higher than the set value, the first circulation pipeline of the liquid cooling system in the cabinet can be turned on to enhance the cooling of the battery module 27 .

[0074] When the dew point temperature of the air in the cabinet decreases, the flow rate of the second circulation pipeline of the air cooling system or the working efficiency of the electric heater 46 is adjusted at any time. Increasing the flow rate of the second circulation pipeline can increase the heat exchange between the air-cooled evaporator 43 and the air, reduce the air temperature so that the air temperature is below the dew point temperature, and condensate is precipitated from the air; then the low-temperature air is heated by the electric heater 46 when passing through the electric heater 46, and the air temperature is raised to above the dew point temperature.

[0075] In step S1, before the battery is started, if the temperature inside the cabinet is lower than the start-up setting value, the fan 35 of the fan assembly 36 and the electric heater 46 need to be turned on until the internal ambient temperature of the battery cabinet 25 reaches the battery safe operating ambient temperature.

[0076] Optionally, the system also includes a central control unit 1, a phase change refrigeration control unit 5, and a battery cabinet temperature control unit 26. Among them, the phase change refrigeration control unit 5 is used to monitor and control the liquid cooling system outside the cabinet; according to the temperature and pressure value of the refrigerant in the liquid cooling system outside the cabinet, the opening state of each pipeline and the valve on the pipeline is adjusted. For example: the phase change refrigeration control unit 5 is connected to the low liquid level switch 14 and the high liquid level switch 13 in the low pressure circulation barrel 12. When the liquid level in the low pressure circulation barrel 12 is lower than the low liquid level switch 14, the low liquid level switch 14 sends a signal to the phase change refrigeration control unit 5; after receiving the liquid level signal, the phase change refrigeration control unit 5 sends a signal to the liquid inlet pipe in the low pressure circulation barrel 12, so that the valve on the liquid inlet pipe is opened, and the refrigerant is transported to the low pressure circulation barrel 12, so that the liquid level in the low pressure circulation barrel 12 rises; at the same time, the phase change refrigeration control unit 5 also sends a signal to the refrigerant pump 15 to stop the operation of the refrigerant pump 15 and cut off the delivery of the refrigerant to the liquid cooling system in the cabinet.

[0077] In addition, the phase change refrigeration control unit 5 also controls the on / off state of the compressor 2, the power of the condensing fan 6, the flow rate of the oil return pipeline, the flow rate of the auxiliary oil return pipe, and the like.

[0078] The battery cabinet temperature control unit 26 is connected to the temperature detection sensors on each battery module 27 in the battery cabinet 25, the temperature sensor in the battery cabinet 25, the temperature and humidity sensor 40 in the battery cabinet 25, the first flow regulating valve 28, the second flow regulating valve 32, the auxiliary expansion valve 33, etc. When the temperature in the battery cabinet 25 is too high or the temperature of the battery module 27 is high, the battery cabinet temperature control unit 26 sends a signal to the first flow regulating valve 28, the second flow regulating valve 32, the auxiliary expansion valve 33, etc. to enhance the cooling effect.

[0079] The central control unit 1 is electrically connected to the phase change refrigeration control unit 5 and the battery cabinet temperature control unit 26, and controls the phase change refrigeration control unit 5 and the battery cabinet temperature control unit 26. The central control unit 1 is a controller integrating temperature control and liquid level control, such as the HUEFLOW intelligent multi-loop measurement and control instrument, which can realize the display, communication and control of multiple data such as temperature, pressure, and liquid level.

[0080] The control method of the phase-change liquid-cooled energy storage heat and moisture separation refrigeration system provided by the present invention realizes the cooling of the battery module 27 and the air inside the cabinet by controlling the start-up and adjustment of the air cooling system, the liquid cooling system inside the cabinet and the liquid cooling system outside the cabinet; the temperature of the air inside the cabinet is lowered by the air cooling system and the liquid cooling system inside the cabinet, and the temperature difference between the air inside the cabinet and the battery module 27 is reduced. By making the actual temperature of the air in the battery cabinet 25 higher than its dew point temperature, the condensation of condensed water in the cabinet after the air is cooled is avoided.

[0081] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. Phase-change liquid cooling energy storage heat and moisture separation refrigeration system, characterized in that: include: A battery cabinet, wherein a plurality of battery modules are provided in the battery cabinet; a low-pressure circulation barrel containing a refrigerant is arranged outside the battery cabinet; An air cooling system, comprising a fan assembly arranged at the bottom of the inner cavity of the battery cabinet, wherein the fan assembly comprises a fan, an air-cooled evaporator, and an electric heater arranged in sequence from front to back, and the gaps between the battery module and the front and rear walls of the battery cabinet and the gaps between adjacent battery modules are interconnected to form a circulating cooling air duct; the air outlet temperature of the fan assembly is higher than the dew point temperature of the air in the battery cabinet; The in-cabinet liquid cooling system is connected to the low-pressure circulation barrel by means of a liquid supply pipeline and an air return pipeline; the in-cabinet liquid cooling system includes a first circulation pipeline and a second circulation pipeline; the first circulation pipeline includes a first liquid supply pipe connecting the liquid supply pipeline and the refrigerant inlet of the battery module, and a first air return pipe connecting the air return pipeline and the refrigerant outlet of the battery module; the second circulation pipeline includes a second liquid supply pipe connecting the liquid supply pipeline and the inlet end of the air-cooled evaporator, and a second air return pipe connecting the outlet end of the air-cooled evaporator and the air return pipeline; An air distribution plate is installed at the rear of the battery cabinet, and the air distribution plate divides the battery cabinet into a rear air duct for connecting the fan assembly and an installation space for installing the battery module, and the installation space is located in front of the rear air duct; a plurality of ventilation holes connecting the rear air duct and the installation space are opened on the air distribution plate; A condensate water collecting tray is arranged at the lower part of the fan assembly, and a condensate water drainage hose is arranged at the lower end of the condensate water collecting tray.

2. The phase-change liquid cooling energy storage heat and moisture separation refrigeration system according to claim 1, characterized in that: A plurality of battery modules are longitudinally arranged at equal intervals in the installation space; a front air duct is provided between the front end of the battery module and the front side wall of the battery cabinet, and a horizontal air duct is formed by the gap between adjacent battery modules; the horizontal air duct connects the rear air duct and the front air duct.

3. The phase-change liquid cooling energy storage heat and moisture separation refrigeration system according to claim 1, characterized in that: The plurality of first liquid supply pipes on the same liquid supply pipeline are all arranged in parallel.

4. The phase-change liquid cooling energy storage heat and moisture separation refrigeration system according to claim 1, characterized in that: Also includes: The external liquid cooling system includes a compressor, a condenser, a main expansion valve and the low-pressure circulation barrel; an oil separator is arranged between the compressor and the condenser, and an oil return pipeline is arranged at the lower end of the oil separator. The lubricating oil in the refrigerant enters the oil return pipeline from the oil separator and passes through the oil cooler, the oil return capillary and the oil return solenoid valve in sequence before re-entering the compressor; the temperature of the refrigerant in the low-pressure circulation barrel is higher than the dew point temperature of the air in the battery cabinet.

5. The phase-change liquid cooling energy storage heat and moisture separation refrigeration system according to claim 4, characterized in that: The exhaust pipe on the low-pressure circulation barrel is connected to the compressor, and an auxiliary oil return pipe is also provided in the low-pressure circulation barrel. One end of the auxiliary oil return pipe is located inside the low-pressure circulation barrel, and the upper end of the auxiliary oil return pipe passes through the low-pressure circulation barrel and is connected to the exhaust pipe by means of an oil return nozzle; the auxiliary oil return pipe is provided with a regulating hand valve and an oil return sight glass.

6. The phase-change liquid cooling energy storage heat and moisture separation refrigeration system according to claim 4, characterized in that: An auxiliary cooling circuit is also provided between the condenser and the main expansion valve, and the auxiliary cooling circuit is connected to the oil cooler for cooling the high-temperature and high-pressure lubricating oil in the oil cooler.

7. A control method for a phase-change liquid-cooled energy storage heat-moisture separation refrigeration system according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. After the battery is started, the liquid cooling system inside the cabinet is turned off and the liquid cooling system outside the cabinet is turned on; S2. When the liquid level in the low-pressure circulation barrel is higher than the low liquid level and the temperature in the cabinet is higher than the set value, the second circulation pipeline and air cooling system of the liquid cooling system in the cabinet are turned on; the air outlet temperature of the fan assembly is higher than the dew point temperature in the cabinet; S3. When the temperature of the battery module is higher than the set value, the first circulation pipeline of the liquid cooling system in the cabinet is opened; S4. When the dew point temperature in the cabinet drops, adjust the flow rate of the second circulation pipeline of the air cooling system or the working efficiency of the electric heater at any time.

8. The control method of the phase-change liquid-cooled energy storage heat and moisture separation refrigeration system according to claim 7, characterized in that: In step S1, before the battery is started, if the temperature inside the cabinet is lower than the start-up setting value, the fan and electric heater of the fan assembly need to be turned on until the internal ambient temperature of the battery cabinet reaches the safe operating ambient temperature of the battery.

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