Energy storage system and method combining liquefied compressed air energy storage and pumped storage

Abstract

The invention relates to the technical field of electric energy physical energy storage systems, in particular to a novel energy storage system combining liquefied compressed air energy storage and pumped storage, and belongs to the technical field of electric energy physical energy storage systems. The energy storage system comprises an air compression subsystem, a turbine expansion power generation subsystem, a low-temperature pumped storage subsystem, a heat storage subsystem and a cold storage subsystem. Liquefied air is used as a medium, the pumped storage technology and the compressed air energy storage technology are effectively combined, the capacity of the novel energy storage system can be increased, the construction investment and land acquisition and immigrant cost are greatly reduced, and the influence on the environment and the site selection requirement are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of electric energy physical energy storage systems, and particularly relates to an energy storage system and method combining liquefied compressed air energy storage and pumped-storage energy storage. Background Art

[0002] With the implementation of building a new power system with new energy as the main body, the installed capacity of wind and light has continued to expand rapidly. The new power system has a strong demand for energy storage, and the construction of energy storage power stations is imminent. Currently, mature energy storage technologies include pumped-storage energy storage technology, compressed air energy storage technology, etc.

[0003] Currently, pumped-storage energy storage technology is the long-term, high-efficiency, and green long-duration energy storage technology and means with the largest energy storage capacity, the most economical and reliable at present, and is the main force in promoting the consumption of new energy. However, the existing pumped-storage energy storage resource reserve sites far cannot meet the demand for the scale of energy storage power stations in the energy plan. At the same time, there are the following problems in the construction and development of pumped-storage power stations: 1) The upper and lower reservoir site selections of conventional pumped-storage power stations have high requirements, large land acquisition areas, and many environmental constraints; 2) The underground cavern group system is complex, has high geological requirements, large project investment, long construction periods, and high construction risks.

[0004] Compressed air energy storage technology is a new type of electric power energy storage technology with large capacity, long time, high efficiency, flexible layout, and relatively short construction period. It can provide peak shaving, frequency modulation, standby, rotational inertia, and accident emergency recovery services for the power system, meeting the needs of building a new power system with new energy as the main body, and having a relatively broad industrial development space. Conventional compressed air energy storage power stations require a large sealed space as a gas storage tank. At present, the main methods of gas storage tanks are pipeline steel, salt caverns, artificial caverns, etc. The cost of pipeline steel is relatively high at present, which limits the possibility of its large-scale application; the cost of salt caverns is relatively low, but its application is restricted by the distribution conditions of natural resources, having certain limitations; mine caves are widely distributed, but the gas tightness is poor. Artificial caverns have good airtightness, but have limitations such as high cost and small volume. Summary of the Invention

[0005] Aiming at the deficiencies existing in the prior art, the purpose of the present invention is to provide a new type of energy storage system combining liquefied compressed air energy storage and pumped-storage energy storage. By using liquefied air and gaseous air as media, the installed capacity of the energy storage system can be increased, and the construction investment of the system can be reduced.

[0006] To achieve the above purpose, the present invention is realized through the following technical solutions:

[0007] In the first aspect, the present invention provides an energy storage system combining liquefied compressed air energy storage and pumped-storage energy storage, including:

[0008] The air compression subsystem, including an air compressor and a liquefaction device, is configured such that during energy storage, the air compressor can utilize the surplus electric energy of the power grid system to convert the outdoor normal-pressure air into high-pressure air, and after being processed by the liquefaction device, it is transformed into low-temperature liquefied air;

[0009] The turbine expansion power generation subsystem, including a gasification device and a turbine, is configured such that during power generation, the gasification device converts the low-temperature liquid air into normal-temperature high-pressure gaseous air and drives the turbine to convert mechanical energy into electric energy and transmit it to the power grid system;

[0010] The low-temperature pumped storage subsystem, including a liquefied air storage tank higher than the liquefaction device and the gasification device, is configured such that during power generation, the low-temperature pumped storage subsystem can utilize the liquid level difference between the liquefied air storage tank and the inlet of the gasification device for power generation, converting the potential energy of the liquefied air into mechanical energy and further into electric energy and transmitting it to the power grid system; during energy storage, the low-temperature pumped storage subsystem can utilize the surplus electric energy of the power grid system to pump the low-temperature liquefied air at the outlet of the liquefaction device into the liquefied air storage tank to store it as the potential energy of the liquefied air.

[0011] As a further optimized solution of the present invention, the air compression subsystem further includes an air filter, a first heat exchanger, and a cold dryer. The air compressor is connected to the power grid system through a first generator motor, a medium-voltage cable, a transformer, and a high-voltage cable. An air filter is provided in front of the air compressor. The air compressor is connected to the liquefaction device through a first gas transmission pipeline. The liquefaction device is connected to the low-temperature pumped storage subsystem through a first liquid transmission pipeline and a third liquid transmission pipeline. The first heat exchanger, the first gas transmission pipeline ball valve, the cold dryer, and the first pressure transmitter are installed on the first gas transmission pipeline between the air compression and liquefaction devices. The air compressor is also used to provide a gas source for the medium-pressure gas-consuming objects in the power station.

[0012] As a further optimized solution of the present invention, the turbine expansion power generation subsystem further includes a gas storage tank, a first generator motor, and a second heat exchanger. The turbine is connected to the power grid system through a first generator motor, a medium-voltage cable, a transformer, and a high-voltage cable. The turbine is connected to the gasification device through a second gas transmission pipeline. The gasification device is connected to the low-temperature pumped storage subsystem through a second liquid transmission pipeline and a third liquid transmission pipeline. The second heat exchanger, the second gas transmission pipeline ball valve, and the second pressure transmitter are installed on the second gas transmission pipeline between the turbine and the gasification device. The turbine is connected to the gas storage tank through the second gas transmission pipeline. The third gas transmission pipeline ball valve and the fifth pressure transmitter are installed on the second gas transmission pipeline between the turbine and the gas storage tank.

[0013] As a further optimization solution of the present invention, the low-temperature pumped storage energy subsystem further includes a low-temperature pump-turbine and a second motor-generator. The liquefied air storage tank is connected to the low-temperature pump-turbine through a fourth liquid delivery pipeline. The low-temperature pump-turbine is connected to the air compression subsystem through a third liquid delivery pipeline and a first liquid delivery pipeline. The low-temperature pump-turbine is connected to the turbine expansion power generation subsystem through a third liquid delivery pipeline and a second liquid delivery pipeline. The second motor-generator is connected to the power grid system through a medium-voltage cable, a transformer, and a high-voltage cable.

[0014] As a further optimization solution of the present invention, the low-temperature pumped storage energy subsystem further includes a first water hammer elimination tank and a second water hammer elimination tank. A liquid level transmitter and a third temperature transmitter are installed on the liquefied air storage tank. The second water hammer elimination tank and the second ball valve are sequentially installed on the fourth liquid delivery pipeline in front of the low-temperature pump-turbine. The first water hammer elimination tank and the first ball valve are sequentially installed on the third liquid delivery pipeline behind the low-temperature pump-turbine. The first liquid delivery pipeline ball valve, the first temperature transmitter, and the third pressure transmitter are installed on the first liquid delivery pipeline between the low-temperature pumped storage energy subsystem and the liquefaction device. The second liquid delivery pipeline ball valve, the second temperature transmitter, and the fourth pressure transmitter are installed on the second liquid delivery pipeline between the low-temperature pumped storage energy subsystem and the gasification device.

[0015] As a further optimization solution of the present invention, the energy storage system further includes a heat storage subsystem respectively connected to the turbine expansion power generation subsystem and the air compression subsystem. The heat storage subsystem is configured to: store the heat generated by the air compressor during energy storage; transfer the stored heat to the high-pressure gas entering the turbine during power generation.

[0016] As a further optimization solution of the present invention, the heat storage subsystem includes a heat storage tank, a first heat medium delivery pipeline, and a second heat medium delivery pipeline. The heat storage tank is connected to the first heat exchanger in the air compression subsystem through the first heat medium delivery pipeline. The heat storage tank is connected to the second heat exchanger in the turbine expansion power generation subsystem through the second heat medium delivery pipeline.

[0017] As a further optimization solution of the present invention, the energy storage system further includes a cold storage subsystem respectively connected to the turbine expansion power generation subsystem and the air compression subsystem. The cold storage subsystem is configured to: store the cold energy generated by the gasification device during power generation; transfer the stored cold energy to the high-pressure gaseous air entering the liquefaction device during energy storage.

[0018] As a further optimization solution of the present invention, the cold storage subsystem includes a cold storage tank, a first cold medium delivery pipeline, and a second cold medium delivery pipeline. The cold storage tank is connected to the liquefaction device through the first cold medium delivery pipeline. The cold storage tank is connected to the gasification device through the second cold medium delivery pipeline.

[0019] In a second aspect, the present invention provides a control method for an energy storage system combining liquefied compressed air energy storage and pumped storage, comprising the following steps:

[0020] When operating in an energy storage mode is required, the grid system transmits surplus electric energy to the first generator-motor via a transformer to be converted into mechanical energy, driving the air compressor to start, converting outdoor air into high-pressure gaseous air, converting it into liquid air via a liquefaction device, and transmitting it to the cryogenic pump-turbine. At this time, the cryogenic pump-turbine operates in the pump condition. The grid system transmits surplus electric energy to the second generator-motor via a transformer to be converted into mechanical energy, and converts it into the potential energy of liquefied air through the cryogenic pump-turbine, pumping the liquefied air into the upstream liquefied air storage tank; when the liquid level of the upstream liquefied air storage tank rises to the normal storage water level or the power system does not need to operate in the energy storage mode, the system stops energy storage, and the air compressor and the cryogenic pump-turbine stop working;

[0021] When operating in a power generation mode is required, the cryogenic pump-turbine operates in the power generation condition, converting the potential energy of the liquefied air in the upstream liquefied air storage tank into mechanical energy, and converting it into electric energy via the second generator-motor and transmitting it to the grid system via a transformer; at the same time, the liquefied air flowing out of the cryogenic pump-turbine is transported to a gasification device, converted into high-pressure gaseous air via the gasification device, driving the turbine to rotate, and the mechanical energy generated by the rotation of the turbine is converted into electric energy via the first generator-motor and transmitted to the grid system via a transformer; when the liquid level of the upstream liquefied air storage tank drops to the dead water level or the power system does not need to operate in the power generation mode, the system stops power generation, and the cryogenic pump-turbine and the turbine stop working.

[0022] Compared with the prior art, the present invention has the following remarkable advantages:

[0023] (1) Compared with the pumped storage technology in the related art, the present invention ingeniously uses liquefied air as a medium, and uses the upstream liquefied air storage tank to play the role of an upper reservoir, simplifying the complicated underground cavern group, and not setting a lower reservoir at the same time, thereby reducing the construction investment, the cost of land acquisition and resettlement, reducing the impact on the environment and the siting requirements. At the same time, the density of liquefied air is greater than that of water, so the capacity of the pumped storage unit can be increased under the same head conditions. By using a cryogenic pump-turbine, it can work safely, stably and efficiently in low-temperature liquid air for a long time.

[0024] (2) Compared with the compressed air energy storage technology in the related art, the present invention ingeniously uses liquefied air as a storage medium, converting high-pressure gaseous air into liquid air, which can greatly reduce the volume of the gas storage cavern required for conventional compressed air energy storage, reduce the impact on the environment and the siting requirements of the gas storage cavern, and thus reduce the construction investment. At the same time, the turbine and the air compressor share the first generator-motor, so as to avoid separately setting generators and motors for the turbine and the air compressor, and a large amount of equipment investment can be saved.

[0025] (3) The present invention ingeniously combines the liquefied compressed air energy storage technology with the pumped-storage technology, increasing the power station capacity and achieving a more significant energy storage effect, and being able to better play roles such as peak shaving, valley filling, and phase regulation.

[0026] (4) The present invention ingeniously uses a water hammer elimination tank to replace the surge shaft and a first ball valve to replace the tailrace emergency gate, reducing the cost of chamber excavation. At the same time, the gas storage tank in the turbine expansion subsystem can provide a gas source for the low-pressure gas-using objects in the power station, and the air compressor in the air compression subsystem can provide a gas source for the medium-pressure gas-using objects in the power station, thus saving a large amount of equipment investment and construction costs.

[0027] (5) The present invention ingeniously combines the generator used by the turbine with the motor used by the air compressor into a motor-generator, thus saving a large amount of equipment investment. Description of the Drawings

[0028] Figure 1 It is a schematic structural diagram of an energy storage system combining liquefied compressed air energy storage and pumped-storage according to the present invention.

[0029] In the figure: 1. Air compressor; 2. First motor-generator; 3. Turbine; 4. Gas storage tank; 5a. First heat exchanger; 5b. Second heat exchanger; 6. Heat storage tank; 7. Refrigerated dryer; 8. Liquefaction device; 9. Gasification device; 10. Cold storage tank; 11a. First gas pipeline ball valve; 11b. Second gas pipeline ball valve; 11c. Third gas pipeline ball valve; 12a. First liquid pipeline ball valve; 12b. Second liquid pipeline ball valve; 13a. First liquid pipeline; 13b. Second liquid pipeline; 13c. Third liquid pipeline; 13d. Fourth liquid pipeline; 14a. First water hammer elimination tank; 14b. Second water hammer elimination tank; 15. First ball valve; 16. Low-temperature water pump turbine; 17. Second motor-generator; 18. Second ball valve; 19. Liquefied air storage tank; 20. Liquid level transmitter; 21a. First temperature transmitter; 21b. Second temperature transmitter; 21c. Third temperature transmitter; 22a. First pressure transmitter; 22b. Second pressure transmitter; 22c. Third pressure transmitter; 22d. Fourth pressure transmitter; 22e. Fifth pressure transmitter; 23a. First gas pipeline; 23b. Second gas pipeline; 24a. First heat medium conveying pipeline; 24b. Second heat medium conveying pipeline; 25a. First cold medium conveying pipeline; 25b. Second cold medium conveying pipeline; 26. Air filter. Detailed Embodiments

[0030] To enable those skilled in the art to better understand the technical solution of the present invention, the preferred implementation of the present invention will be described below in conjunction with specific embodiments. However, it should be understood that the drawings are only for illustrative purposes and cannot be construed as a limitation of this patent; to better illustrate this embodiment, some components in the drawings will be omitted, enlarged or reduced, which do not represent the dimensions of the actual product; for those skilled in the art, the omission of some well-known structures and their descriptions in the drawings can be understood. The description of the positional relationship in the drawings is only for illustrative purposes and cannot be construed as a limitation of this patent.

[0031] As Figure 1 shown, a new energy storage system combining liquefied compressed air energy storage and pumped hydro energy storage in this embodiment mainly includes an air compression subsystem represented by an air compressor 1, an air filter 26, a first heat exchanger 5a, a first gas pipeline ball valve 11a, a cold dryer 7, a first gas pipeline 23a, a first pressure transmitter 22a, and a liquefaction device 8; a turbine expansion power generation subsystem represented by a turbine 3, a gas storage tank 4, a first power generation motor 2, a second heat exchanger 5b, a second gas pipeline ball valve 11b, a third gas pipeline ball valve 11c, a second gas pipeline 23b, a gasification device 9, a second pressure transmitter 22b, and a fifth pressure transmitter 22e; a low-temperature pumped hydro energy storage subsystem represented by a first liquid pipeline ball valve 12a, a second liquid pipeline ball valve 12b, a first liquid pipeline 13a, a second liquid pipeline 13b, a third liquid pipeline 13c, a fourth liquid pipeline 13d, a first water hammer elimination tank 14a, a second water hammer elimination tank 14b, a first ball valve 15, a low-temperature water pump turbine 16, a second power generation motor 17, a second ball valve 18, a liquefied air storage tank 19, a liquid level transmitter 20, a first temperature transmitter 21a, a second temperature transmitter 21b, a third temperature transmitter 21c, a third pressure transmitter 22c, and a fourth pressure transmitter 22d; a heat storage subsystem represented by a heat storage tank 6, a first heat medium conveying pipeline 24a, and a second heat medium conveying pipeline 24b; and a cold storage subsystem represented by a cold storage tank 10, a first cold medium conveying pipeline 25a, and a second cold medium conveying pipeline 25b.

[0032] In the air compression subsystem, the air compressor 1 is connected to the power grid system through the first power generation motor 2, medium-voltage cable, transformer, and high-voltage cable. An air filter 26 is provided in front of the air compressor 1. The air compressor 1 is connected to the liquefaction device 8 through the first gas transmission pipeline 23a. The liquefaction device 8 is connected to the cryogenic pumped-storage energy subsystem through the first liquid transmission pipeline 13a and the third liquid transmission pipeline 13c. The first heat exchanger 5a, the first gas transmission pipeline ball valve 11a, the refrigerant dryer 7, and the first pressure transmitter 22a are installed on the first gas transmission pipeline 23a between the air compressor 1 and the liquefaction device 8. The air compressor 1 can be used simultaneously to provide a gas source for medium-pressure gas-using objects such as the phase modulation of the power station and the oil pressure device. The air compression subsystem is configured such that during energy storage, the air compression subsystem can utilize the surplus electric energy of the power grid system to convert outdoor atmospheric air into high-pressure air, which is then processed by the liquefaction device 8 and transformed into low-temperature liquefied air.

[0033] It can be understood that in the air compression subsystem, the air filter 26 can effectively filter impurities in outdoor air, prevent them from entering subsequent equipment, reduce equipment wear, and extend the service life of the equipment. The first heat exchanger 5a can perform heat exchange on the air during the compression process, which helps to improve the air compression efficiency and also provides a heat source for the heat storage subsystem. The refrigerant dryer 7 further removes moisture in the high-pressure gaseous air, avoiding the condensation of moisture in subsequent pipelines and equipment, which affects the system performance and equipment safety. The first pressure transmitter 22a can monitor the pressure in the gas transmission pipeline in real time, provide data support for the stable operation of the system, and facilitate the operator to adjust the equipment operation parameters in a timely manner. The air compressor 1 provides a gas source for medium-pressure gas-using objects in the power station, realizing the multi-functional utilization of the equipment and improving the resource utilization rate. Overall, this subsystem efficiently converts atmospheric air into low-temperature liquefied air, laying a foundation for the subsequent energy storage link, and through the coordinated operation of each component, ensuring the stable and efficient operation of the system.

[0034] In the turbine expansion power generation subsystem, the turbine 3 is connected to the power grid system through the first power generation motor 2, medium-voltage cable, transformer, and high-voltage cable. The turbine 3 is connected to the gasification device 9 through the second gas transmission pipeline 23b. The gasification device 9 is connected to the cryogenic pumped-storage energy subsystem through the second liquid transmission pipeline 13b and the third liquid transmission pipeline 13c. The second heat exchanger 5b, the second gas transmission pipeline ball valve 11b, and the second pressure transmitter 22b are installed on the second gas transmission pipeline 23b between the turbine 3 and the gasification device 9. The turbine 3 is connected to the gas tank 4 through the second gas transmission pipeline 23b. The third gas transmission pipeline ball valve 11c and the fifth pressure transmitter 22e are installed on the second gas transmission pipeline 23b between the turbine 3 and the gas storage tank 4. The gasification device 9 converts the cryogenic liquid air into normal-temperature high-pressure gaseous air and further drives the turbine 3 to do work to convert mechanical energy into electrical energy and transmit it to the power grid system. The turbine 3 is connected to the first power generation motor 2 and is connected to the power grid system through the outlet bus, transformer, and high-voltage cable. The gas storage tank 4 is used to provide a constant gas source for low-pressure gas-consuming objects such as braking and purging of the power station. The turbine expansion power generation subsystem is configured such that during power generation, the high-pressure gaseous air at the outlet of the gasification device 9 of the turbine expansion power generation subsystem drives the turbine 3 to convert mechanical energy into electrical energy and transmit it to the power grid system.

[0035] The turbine 3 and the air compressor 1 share the first power generation motor 2. During power generation, the turbine 3 expands and does work, and the first power generation motor 2 rotates clockwise. During energy storage, the air compressor 1 compresses air, and the first power generation motor 2 rotates counterclockwise. The first power generation motor 2 is connected to the power grid system through the outlet bus, transformer, and high-voltage cable.

[0036] It can be understood that in the turbine expansion power generation subsystem, the second heat exchanger 5b uses the heat stored in the heat storage subsystem to heat the high-pressure gaseous air, improving the work capacity of the air and thus enhancing the power generation efficiency. The second pressure transmitter 22b and the fifth pressure transmitter 22e monitor the pressure in the gas transmission pipeline in real time to ensure that the gasification device 9 and the turbine 3 operate under appropriate pressure conditions, guaranteeing the safety and stability of the system. The gas storage tank 4 provides a constant gas source for low-pressure gas-consuming objects such as braking and purging of the power station, meeting the various gas consumption requirements of the power station and improving the functionality of the system. The turbine 3 cooperates with the first power generation motor 2 to convert the energy of the high-pressure gaseous air into electrical energy and transmit it to the power grid system, realizing the power generation function of the energy storage system. And by sharing the first power generation motor 2 with the air compressor 1, the equipment investment cost is saved.

[0037] In the cryogenic pumped-storage energy subsystem, the liquefied air storage tank 19 serves as the upper reservoir of the cryogenic pumped-storage energy subsystem. The cryogenic pump-turbine 16 is connected to the liquefied air storage tank 19 through the fourth liquid delivery pipeline 13d. The cryogenic pump-turbine 16 is connected to the air compression subsystem through the third liquid delivery pipeline 13c and the first liquid delivery pipeline 13a, and is connected to the turbine expansion power generation subsystem through the third liquid delivery pipeline 13c and the second liquid delivery pipeline 13b. The liquefied air storage tank 19 is equipped with a liquid level transmitter 20 and a third temperature transmitter 21c. The second water hammer elimination tank 14b and the second ball valve 18 are successively installed on the fourth liquid delivery pipeline 13d in front of the cryogenic pump-turbine 16. The first water hammer elimination tank 14a and the first ball valve 15 are successively installed on the third liquid delivery pipeline 13c behind the cryogenic pump-turbine 16. The first water hammer elimination tank 14a and the second water hammer elimination tank 14b can replace the surge tank of a traditional pumped-storage power station, and the first ball valve 15 can replace the tailwater emergency gate of a traditional pumped-storage power station. The first liquid delivery pipeline ball valve 12a, the first temperature transmitter 21a, and the third pressure transmitter 22c are installed on the first liquid delivery pipeline 13a between the cryogenic pumped-storage energy subsystem and the liquefaction device 8 in the air compression subsystem. The second liquid delivery pipeline ball valve 12b, the second temperature transmitter 21b, and the fourth pressure transmitter 22d are installed on the second liquid delivery pipeline 13b between the cryogenic pumped-storage energy subsystem and the gasification device 9 in the turbine expansion power generation subsystem. The cryogenic pump-turbine 16 can operate efficiently and stably at low temperatures. The cryogenic pump-turbine 16 is connected to the second generator-motor 17 and is connected to the power grid system through the outlet busbar, transformer, and high-voltage cable. The cryogenic pumped-storage energy subsystem is connected to the power grid system. The cryogenic pumped-storage energy subsystem is configured to: using liquefied air as the medium, during power generation, the cryogenic pumped-storage energy subsystem can utilize the liquid level difference between the liquefied air storage tank and the cryogenic liquefied air at the inlet of the gasification device 9 in the turbine expansion power generation subsystem to generate electricity, convert the potential energy of the liquefied air into mechanical energy and further into electrical energy and transmit it to the power grid system; during energy storage, the cryogenic pumped-storage energy subsystem can utilize the surplus electrical energy of the power grid system to pump the cryogenic liquefied air at the outlet of the liquefaction device 8 in the air compression subsystem into the liquefied air storage tank to convert it into the potential energy of the liquefied air for storage.

[0038] It can be understood that in the cryogenic pumped - storage subsystem, the liquefied - air storage tank 19 serves as the upper reservoir and cooperates with the cryogenic pump - turbine 16 to achieve the mutual conversion between the potential energy of liquefied air and electrical energy. The liquid - level transmitter 20 monitors the liquid level of the liquefied - air storage tank 19 in real time, providing key data for the energy - storage and power - generation control of the system to ensure that the system operates within the safe liquid - level range. The first surge - tank 14a and the second surge - tank 14b replace the surge shaft of the traditional pumped - storage power station, effectively eliminating the water - hammer phenomenon, protecting the safety of pipelines and equipment, and reducing the cost and space requirements for constructing the surge shaft. The first ball valve 15 replaces the tail - water emergency gate of the traditional pumped - storage power station and can quickly cut off the water flow in case of an emergency to ensure the safety of the system. The first temperature transmitter 21a, the second temperature transmitter 21b, and the third temperature transmitter 21c monitor the temperature at different positions in real time, which helps to understand the operating state of the system and detect abnormal conditions in a timely manner. The third pressure transmitter 22c and the fourth pressure transmitter 22d monitor the pressure in the liquid - conveying pipeline, providing guarantee for the stable operation of the system. The cryogenic pump - turbine 16 cooperates with the second generator - motor 17 to achieve the efficient conversion of energy during the energy - storage and power - generation processes and can operate stably in a low - temperature environment, ensuring the reliability and adaptability of the system.

[0039] In the heat - storage subsystem, the heat - storage tank 6 is connected to the first heat - exchanger 5a of the air - compression subsystem through the first heat - medium conveying pipeline 24a, and the heat - storage tank 6 is connected to the second heat - exchanger 5b in the turbine - expansion power - generation subsystem through the second heat - medium conveying pipeline 24b. The heat - storage subsystem is configured such that during energy - storage, it stores the heat generated by the air compressor in the air - compression subsystem; during power - generation, it transfers the heat to the high - pressure gas entering the turbine, so that when the turbine operates, there is no need to use external energy to heat the air, achieving a non - supplementary - combustion effect.

[0040] It can be understood that in the heat - storage subsystem, the heat - storage tank 6 stores the heat generated by the air compressor, realizing the recycling of energy. During power - generation, the heat is transferred to the high - pressure gas entering the turbine through the first heat - medium conveying pipeline 24a and the second heat - medium conveying pipeline 24b, increasing the inlet temperature of the turbine, enhancing the work - doing ability of the gas, thereby improving the power - generation efficiency. At the same time, it achieves a non - supplementary - combustion effect, reducing additional energy consumption and environmental pollution.

[0041] In the cold - storage subsystem, the cold - storage tank 10 is connected to the liquefaction device 8 in the air - compression subsystem through the first cold - medium conveying pipeline 25a, and the cold - storage tank 10 is connected to the gasification device 9 in the turbine - expansion power - generation subsystem through the second cold - medium conveying pipeline 25b. The cold - storage subsystem is configured such that during power - generation, it stores the cold generated by the gasification device 9 in the turbine - expansion power - generation subsystem; during energy - storage, it transfers the cold to the liquefaction device 8 in the air - compression subsystem, so that there is no need to supplement cold from outside the system.

[0042] It is understandable that in the cold energy storage subsystem, the cold energy storage tank 10 stores the cold energy generated by the gasification device 9 during power generation, and transfers the cold energy to the liquefaction device 8 through the first cold medium conveying pipeline 25a and the second cold medium conveying pipeline 25b during energy storage, reducing the energy consumption of the liquefaction device 8 when liquefying high-pressure gaseous air, reducing the demand for additional cold energy supplement from outside the system, improving the energy utilization efficiency of the system, and realizing the recycling of cold energy.

[0043] The energy storage mechanism of the present invention is different from the traditional compressed air energy storage mechanism and the pumped-storage energy storage mechanism. The present invention uses liquefied air as the energy storage medium.

[0044] When the power generation of renewable energy increases sharply or the power consumption load decreases, resulting in an abundance of electrical energy in the power grid system, and when the present invention needs to operate in an energy storage mode, the second gas transmission pipeline ball valve 11b, the third gas transmission pipeline ball valve 11c, and the second liquid transmission pipeline ball valve 12b are closed, and the first gas transmission pipeline ball valve 11a, the first liquid transmission pipeline ball valve 12a, the first ball valve 15, and the second ball valve 18 are opened. The power grid system transmits the surplus electrical energy to the first power generation motor 2 through the transformer to be converted into mechanical energy, driving the air compressor to start, converting the outdoor air filtered by the air filter 26 into high-pressure gaseous air, and filtering out the impurities and moisture in the high-pressure gaseous air through the cold dryer 7, and converting it into liquid air through the liquefaction device 8. The liquid air reaches the low-temperature water pump turbine 16 through the first liquid transmission pipeline 13a and the third liquid transmission pipeline 13c. At this time, the low-temperature water pump turbine 16 operates in the water pump mode. The power grid system transmits the surplus electrical energy to the second power generation motor 17 through the transformer to be converted into mechanical energy, and is converted into the potential energy of the liquid air through the low-temperature water pump turbine 16, and pumps the liquid air into the upstream liquefied air storage tank 19; when the liquid level of the upstream liquefied air storage tank rises to the normal storage water level or the power system does not require the present invention to operate in an energy storage mode, the system stops energy storage, the air compressor 1 and the low-temperature water pump turbine 16 stop working, and the first gas transmission pipeline ball valve 11a, the first liquid transmission pipeline ball valve 12a, and the second ball valve 18 are closed.

[0045] When the power generation of renewable energy drops sharply or the power consumption load increases, resulting in insufficient electric energy in the power grid system, and when the present invention needs to operate in a power generation mode, the first gas pipeline ball valve 11a and the first liquid pipeline ball valve 12a are closed. The second ball valve 18, the second liquid pipeline ball valve 12b, the second gas pipeline ball valve 11b and the third gas pipeline ball valve 11c are opened. The low-temperature water pump turbine 16 operates in a power generation condition, converting the potential energy of the liquefied air in the upstream liquefied air storage tank 19 into mechanical energy, and converting it into electric energy through the second power generation motor 17 and transporting it to the power grid system via a transformer; at the same time, the liquefied air flowing out of the low-temperature water pump turbine 16 reaches the gasification device 9 through the third liquid pipeline 13c and the second liquid pipeline 13b, and is converted into high-pressure gaseous air through the gasification device 9 to drive the turbine 3 to rotate. The mechanical energy generated by the rotation of the turbine 3 is converted into electric energy through the first power generation motor 2 and transported to the power grid system via a transformer; when the liquid level of the upstream liquefied air storage tank 19 drops to the dead water level or the power system does not require the present invention to operate in a power generation mode, the system stops generating electricity, the low-temperature water pump turbine 16 and the turbine 3 stop working, and the second ball valve 18, the second liquid pipeline ball valve 12b, the second gas pipeline ball valve 11b and the third gas pipeline ball valve 11c are closed.

[0046] Based on the description and drawings of the present invention, those skilled in the art can easily manufacture or use an energy storage system and method combining liquefied compressed air energy storage and pumped storage of the present invention, and can produce the positive effects recorded in the present invention.

[0047] Unless otherwise specified, in the present invention, if there are terms such as "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the orientation or positional relationship in the present invention are only for illustrative purposes and cannot be understood as a limitation of this patent. For those of ordinary skill in the art, the specific meanings of the above terms can be understood in combination with the drawings and according to specific circumstances.

[0048] Unless otherwise clearly defined and limited, in the present invention, if there are terms such as "set", "connected" and "connected", they should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Any simple modification or equivalent change made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. An energy storage system combining liquefied compressed air energy storage and pumped water energy storage, characterized in that: include: The air compression subsystem, including an air compressor and a liquefaction device, is configured such that during energy storage, the air compressor can use the surplus electric energy of the power grid system to convert outdoor normal-pressure air into high-pressure air, and then convert it into low-temperature liquefied air after being processed by the liquefaction device; The turbine expansion power generation subsystem includes a gasifier and a turbine, and is configured such that: when generating electricity, the gasifier converts low-temperature liquid air into normal-temperature and high-pressure gaseous air, and drives the turbine to convert mechanical energy into electrical energy and transmit it to the power grid system; The low-temperature pumped storage subsystem includes a liquefied air storage tank that is higher than the liquefaction device and the gasification device, and is configured as follows: when generating electricity, the low-temperature pumped storage subsystem can use the liquid level difference between the liquefied air storage tank and the inlet of the gasification device to generate electricity, convert the potential energy of the liquefied air into mechanical energy and further convert it into electrical energy for transmission to the power grid system; when storing energy, the low-temperature pumped storage subsystem can use the surplus electrical energy of the power grid system to pump the low-temperature liquefied air at the outlet of the liquefaction device into the liquefied air storage tank and convert it into the potential energy of the liquefied air for storage.

2. The energy storage system combining liquefied compressed air energy storage and pumped storage according to claim 1 is characterized in that: The air compression subsystem also includes an air filter, a first heat exchanger and a cold dryer. The air compressor is connected to the power grid system through a first generator motor, a medium-voltage cable, a transformer, and a high-voltage cable. An air filter is arranged in front of the air compressor. The air compressor is connected to the liquefaction device through a first gas pipeline. The liquefaction device is connected to the low-temperature pumped storage subsystem through a first liquid infusion pipeline and a third liquid infusion pipeline. The first heat exchanger, the first gas pipeline ball valve, the cold dryer, and the first pressure transmitter are installed on the first gas pipeline between the air compression and liquefaction devices. The air compressor is also used to provide gas source to the medium-pressure gas users of the power station.

3. The energy storage system combining liquefied compressed air energy storage and pumped storage according to claim 1 is characterized in that: The turbine expansion generator subsystem also includes a gas storage tank, a first generator motor and a second heat exchanger. The turbine is connected to the power grid system through the first generator motor, a medium-voltage cable, a transformer and a high-voltage cable. The turbine is connected to the gasification device through a second gas pipeline. The gasification device is connected to the low-temperature pumped storage subsystem through a second liquid pipeline and a third liquid pipeline. The second heat exchanger, the second gas pipeline ball valve and the second pressure transmitter are installed on the second gas pipeline between the turbine and the gasification device. The turbine is connected to the gas storage tank through the second gas pipeline. The third gas pipeline ball valve and the fifth pressure transmitter are installed on the second gas pipeline between the turbine and the gas storage tank.

4. The energy storage system combining liquefied compressed air energy storage and pumped storage according to claim 1 is characterized in that: The low-temperature pumped storage subsystem also includes a low-temperature water pump turbine and a second generator motor. The liquefied air storage tank is connected to the low-temperature water pump turbine through a fourth fluid delivery pipeline. The low-temperature water pump turbine is connected to the air compression subsystem through a third fluid delivery pipeline and a first fluid delivery pipeline. The low-temperature water pump turbine is connected to the turbine expansion subsystem through a third fluid delivery pipeline and a second fluid delivery pipeline. The second generator motor is connected to the power grid system through a medium-voltage cable, a transformer, and a high-voltage cable.

5. The energy storage system combining liquefied compressed air energy storage and pumped storage according to claim 4 is characterized in that: The low-temperature pumped-storage subsystem also includes a first water hammer elimination tank and a second water hammer elimination tank. A liquid level transmitter and a third temperature transmitter are installed on the liquefied air storage tank. The second water hammer elimination tank and the second ball valve are installed in sequence on the fourth liquid delivery pipeline in front of the low-temperature water pump turbine. The first water hammer elimination tank and the first ball valve are installed in sequence on the third liquid delivery pipeline behind the low-temperature water pump turbine. The first liquid delivery pipeline ball valve, the first temperature transmitter, and the third pressure transmitter are installed on the first liquid delivery pipeline between the low-temperature pumped-storage subsystem and the liquefaction device. The second liquid delivery pipeline ball valve, the second temperature transmitter, and the fourth pressure transmitter are installed on the second liquid delivery pipeline between the low-temperature pumped-storage subsystem and the gasification device.

6. The energy storage system combining liquefied compressed air energy storage and pumped storage according to claim 1 is characterized in that: The energy storage system also includes a heat storage subsystem connected to the turbine expansion power generation subsystem and the air compression subsystem respectively. The heat storage subsystem is configured to store the heat generated by the air compressor during energy storage and transfer the stored heat to the high-pressure gas entering the turbine during power generation.

7. The energy storage system combining liquefied compressed air energy storage and pumped storage according to claim 6 is characterized in that: The heat storage subsystem includes a heat storage tank, a first heat medium delivery pipeline, and a second heat medium delivery pipeline. The heat storage tank is connected to the first heat exchanger in the air compression subsystem through the first heat medium delivery pipeline, and the heat storage tank is connected to the second heat exchanger in the turbine expansion power generation subsystem through the second heat medium delivery pipeline.

8. The energy storage system combining liquefied compressed air energy storage and pumped storage according to claim 1 is characterized in that: The energy storage system also includes a cold storage subsystem connected to the turbine expansion power generation subsystem and the air compression subsystem respectively. The cold storage subsystem is configured to store the cold energy generated by the gasification device when generating electricity and transfer the stored cold energy to the high-pressure gaseous air entering the liquefaction device when storing energy.

9. The energy storage system combining liquefied compressed air energy storage and pumped storage according to claim 8 is characterized in that: The cold storage subsystem includes a cold storage tank, a first cold medium delivery pipeline, and a second cold medium delivery pipeline. The cold storage tank is connected to the liquefaction device through the first cold medium delivery pipeline, and the cold storage tank is connected to the gasification device through the second cold medium delivery pipeline.

10. A control method for an energy storage system combining liquefied compressed air energy storage and pumped storage as claimed in any one of claims 1 to 9, characterized in that: The steps include: When it is necessary to operate in energy storage mode, the power grid system transmits the surplus electric energy to the first generator motor via the transformer to be converted into mechanical energy, drives the air compressor to start, converts the outdoor air into high-pressure gaseous air, converts it into liquid air via the liquefaction device, and transmits it to the low-temperature water pump turbine. At this time, the low-temperature water pump turbine operates as a water pump. The power grid system transmits the surplus electric energy to the second generator motor via the transformer to be converted into mechanical energy, and converts it into liquefied air potential energy through the low-temperature water pump turbine, and pumps the liquefied air into the upstream liquefied air storage tank; when the liquid level of the upstream liquefied air storage tank rises to the normal water storage level or the power system does not need to operate in energy storage mode, the system stops energy storage, and the air compressor and the low-temperature water pump turbine stop working; When it is necessary to operate in the power generation mode, the low-temperature water pump turbine operates in the power generation mode, converts the potential energy of the liquefied air in the upstream liquefied air storage tank into mechanical energy, and converts it into electrical energy through the second generator motor and transmits it to the power grid system via the transformer; at the same time, the liquefied air flowing out of the low-temperature water pump turbine is transported to the gasification device, converted into high-pressure gaseous air by the gasification device, drives the turbine to rotate, and the mechanical energy generated by the turbine rotation is converted into electrical energy through the first generator motor and transmitted to the power grid system via the transformer; when the liquid level of the upstream liquefied air storage tank drops to the dead water level or the power system does not need to operate in the power generation mode, the system stops generating electricity, and the low-temperature water pump turbine and turbine stop working.

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