Energy storage system integrating pumped storage and compressed air energy storage

Abstract

The present invention relates to the field of energy storage technology, and discloses a novel energy storage system integrating pumped storage and compressed air, comprising: a pumped storage system, including a first water transmission pipeline; a compressed air energy storage system, including a plurality of sub-compressed air energy storage systems, the plurality of sub-compressed air energy storage systems are arranged on one side of the pumped storage system, the plurality of sub-compressed air energy storage systems are arranged in intervals from high to low, and any sub-compressed air energy storage system is connected to the first water transmission pipeline through a second water transmission pipeline. The present invention improves the capacity of a single form of energy storage, enriches the operating conditions of the energy storage system, and broadens the energy storage adjustment range by jointly operating the compressed air energy storage system with the pumped storage system, which is conducive to promoting the development and construction of small and medium-sized pumped storage power stations. In addition, the plurality of sub-compressed air energy storage systems are arranged in intervals from high to low, realizing the graded energy storage of compressed air potential energy, so that the compressed air energy storage system can operate more efficiently and stably.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage, and in particular to an energy storage system integrating pumped storage and compressed air energy storage. Background Art

[0002] Pumped storage systems and compressed air energy storage systems are currently two common large-scale physical energy storage methods. Among them, the pumped storage system converts electrical energy and water gravity potential energy through pumps or turbines to achieve the storage and release of electrical energy. The compressed air energy storage system uses compressor air to pressurize and turbine expand the air to achieve the storage of electrical energy.

[0003] However, in existing energy storage systems, the commonalities in technical principles between pumped storage systems and compressed air energy storage systems are rarely utilized to integrate the two energy storage systems together, thereby increasing the capacity of a single form of energy storage. Summary of the invention

[0004] In view of this, the present invention provides an energy storage system integrating pumped storage and compressed air energy storage to further improve the flexibility of the electric energy storage system.

[0005] In a first aspect, the present invention provides an energy storage system integrating pumped storage and compressed air energy storage, comprising:

[0006] A pumped storage system, comprising a first water transmission pipeline;

[0007] A compressed air energy storage system comprises a plurality of sub-compressed air energy storage systems, wherein the plurality of sub-compressed air energy storage systems are arranged on one side of the pumped storage system, and the plurality of sub-compressed air energy storage systems are arranged at intervals from high to low, and any one of the sub-compressed air energy storage systems is connected to the first water pipeline via a second water pipeline.

[0008] Beneficial effects: The present invention connects the compressed air energy storage system with the pumped storage system through the second transmission pipeline, so that the compressed air energy storage system and the pumped storage system can operate jointly, which improves the capacity of single-form energy storage, enriches the operating conditions of the energy storage system, and broadens the energy storage adjustment range, which is conducive to promoting the development and construction of small and medium-sized pumped storage power stations. In addition, multiple sub-compressed air energy storage systems are arranged at intervals along the height direction of the mountain, realizing the hierarchical energy storage of compressed air potential energy, thereby making the compressed air energy storage system more efficient and stable.

[0009] In an optional embodiment, the sub-compressed air energy storage system includes a compressor unit, a gas storage reservoir and an expander unit connected in sequence via a first gas pipeline, wherein the gas storage reservoir is connected to the pumped storage system via a second water pipeline.

[0010] Beneficial effects: The present invention connects the compressor unit, the gas storage reservoir and the expander unit in sequence by using the first gas transmission pipeline, so that the compressed air energy storage system can complete the storage or release of electric energy according to actual needs. In addition, the gas storage reservoir is connected to the pumped storage system through the second water transmission pipeline, so that the water in the pumped storage system can freely enter and exit the gas storage reservoir, thereby reducing the pressure change range in the gas storage reservoir during the storage or release of electric energy of the compressed air energy storage system, thereby improving the stability of the operation of the compressed air energy storage system and the utilization rate of the gas storage reservoir volume.

[0011] In an optional embodiment, the gas storage reservoir is provided with a water pipe interface connected to the second water supply pipeline, and the water pipe interface is arranged at one end close to the bottom of the gas storage reservoir.

[0012] Beneficial effect: By arranging the water pipe interface at one end close to the bottom of the gas storage reservoir, the present invention can reduce the number of other equipment used, so that the water in the pumped storage system can still freely enter and exit the gas storage reservoir, thereby facilitating the adjustment of the real-time pressure in the gas storage reservoir by water flow, reducing the pressure variation range in the gas storage reservoir, and further enabling all the air stored in the gas storage reservoir to be used for expansion and power generation, thereby improving the energy conversion efficiency of the compressed air energy storage system.

[0013] In an optional embodiment, a flexible storage device is provided in the gas storage reservoir, and the flexible storage device is connected to the water pipe interface.

[0014] Beneficial effects: The present invention can separate the high-pressure gas in the compressed air energy storage system from the water phase entering the gas storage reservoir by arranging a flexible storage device in the gas storage reservoir, thereby avoiding direct contact between the high-pressure gas and water, thereby reducing the moisture content in the high-pressure gas. At the same time, it can also reduce the probability of rusting of equipment and pipelines and increase the life of the system.

[0015] In an optional implementation, adjacent sub-compressed air energy storage systems are connected via a second air transmission pipeline.

[0016] Beneficial effect: The present invention connects adjacent sub-compressed air energy storage systems through a second gas transmission pipeline, so that high-pressure gas can flow freely between adjacent sub-compressed air energy storage systems, thereby improving the energy storage efficiency of the compressed air energy storage system and reducing energy loss.

[0017] In an optional embodiment, the second gas transmission pipeline includes a gas transmission main pipe and two gas transmission branch pipes, one end of the gas transmission main pipe is connected to the gas storage reservoir in the sub-compressed air energy storage system located above, and the other end is connected to the two gas transmission branch pipes through a three-way valve, and the two gas transmission branch pipes are respectively connected to the air inlet of the compressor unit and the air outlet of the expansion unit in the sub-compressed air energy storage system located below.

[0018] Beneficial effects: The present invention can connect the gas storage reservoir in the upper sub-compressed air energy storage system with the compressor unit and the expander unit in the lower sub-compressed air energy storage system by setting a gas main and two gas branches, and at the same time, can make the gas pipeline more compact in layout and reduce the occupied space. In addition, by setting a three-way valve between the gas main and the two gas branches, the second gas pipeline can connect one of the two gas branches with the gas main according to demand during the process of storing or releasing electric energy in the compressed air energy storage system, and realize graded energy storage and energy release in the compression process and the expansion process respectively, which improves the efficiency of the compressed air energy storage system on the one hand, and ensures the stability of the operation of the compressed air energy storage system on the other hand.

[0019] In an optional embodiment, the three-way valve is a T-type three-way valve, an L-type three-way valve or a straight-type three-way valve.

[0020] Beneficial effect: The present invention adopts any one of the above-mentioned three-way valves to connect one of the two gas transmission branches with the gas transmission main pipe according to needs. On the one hand, it improves the energy storage capacity of the compressed air energy storage system, and on the other hand, it enables the compressed air energy storage system to be flexibly applicable to various working conditions.

[0021] In an optional embodiment, two second gas transmission pipelines are provided between adjacent sub-compressed air energy storage systems, wherein two ends of one of the second gas transmission pipelines are respectively connected to the gas storage reservoir in the upper sub-compressed air energy storage system and the air inlet of the compressor unit in the lower sub-compressed air energy storage system, and two ends of the other second gas transmission pipeline are respectively connected to the gas storage reservoir in the upper sub-compressed air energy storage system and the air outlet of the expansion unit in the lower sub-compressed air energy storage system, and first switch valves are respectively provided on the two second gas transmission pipelines.

[0022] Beneficial effect: The present invention sets a second gas transmission pipeline between the gas storage reservoir in the upper sub-compressed air energy storage system and the compressor unit and the expander unit in the lower sub-compressed air energy storage system, so that the compressed air energy storage system can store or release large amounts of electrical energy, thereby balancing the grid load and avoiding overload or power shortage.

[0023] In an optional implementation, the first switch valve is a one-way valve.

[0024] Beneficial effect: The present invention ensures that the high-pressure gas flows in one direction by setting the first switch valve as a one-way valve, thereby avoiding the problem of high-pressure gas backflow and improving the working efficiency and stability of the system.

[0025] In an optional embodiment, the sub-compressed air energy storage system further includes a first heat exchanger, and the first heat exchanger is respectively connected to the compressor unit and the gas storage reservoir through the first gas transmission pipeline.

[0026] Beneficial effects: Since a large amount of heat is usually generated when the gas is compressed by the compressor unit, the present invention arranges a first heat exchanger between the compressor unit and the gas storage reservoir, so that the sub-compressed air energy storage system can store the heat generated when the gas is compressed, thereby improving the utilization rate of energy.

[0027] In an optional embodiment, the sub-compressed air energy storage system also includes a second heat exchanger, which is connected to the expansion unit and the gas storage reservoir respectively through the first gas transmission pipeline, and a second switch valve is respectively provided between the first heat exchanger and the second heat exchanger and the gas storage reservoir.

[0028] Beneficial effect: Since the gas needs to absorb heat during the expansion process of the expander unit, the present invention sets a second heat exchanger between the expander unit and the gas storage reservoir to use the heat stored in the first heat exchanger to heat the gas in the expander unit. This arrangement can increase the output power of the expander unit and improve the energy storage efficiency of the system on the one hand, and reduce the use of traditional fuel on the other hand.

[0029] In an optional implementation, the pumped storage system further includes an upper reservoir, a reversible pump turbine and a lower reservoir which are sequentially connected via the first water transmission pipeline.

[0030] Beneficial effects: The present invention can not only convert electrical energy into the gravitational potential energy of water by setting a reversible pump turbine, thereby realizing the storage of electrical energy during the low-peak period of electricity consumption, but also can reconvert the gravitational potential energy of water into electrical energy, thereby realizing the release of electrical energy to meet the demand for electrical energy during the peak period of electricity consumption. At the same time, by setting a reversible pump turbine, the number of devices used in the pumped storage system can be reduced, reducing the complexity of the pumped storage system.

[0031] In an optional embodiment, the compressor unit includes an electric motor and a compressor connected to the electric motor.

[0032] Beneficial effect: The present invention can provide better power output and speed control to adapt to different operating requirements by using an electric motor as the power source of the compressor.

[0033] In an optional embodiment, the expander unit includes a generator and an expander connected to the generator.

[0034] Beneficial effect: The present invention can release the electric energy previously stored in the compressed air energy storage system through the cooperation of the expander and the generator, thereby meeting the user's demand for electric energy.

[0035] In an optional embodiment, the gas storage is a combination of one or more of a gas storage tank, a pipeline steel bundle gas storage, an underground salt cavern, an artificial underground chamber, and a tunnel.

[0036] Beneficial effects: The present invention can meet different gas storage needs by selecting different forms of gas storage, while better improving the efficiency and stability of gas storage.

[0037] In an optional embodiment, the gas in the air inlet of the compressor unit is air or carbon dioxide.

[0038] Beneficial effects: The compressed air energy storage system of the present invention compresses compressed air or carbon dioxide through a compressor unit, which can store the potential energy of compressed air, thereby increasing the application scenarios of the compressed air energy storage system.

[0039] In an optional embodiment, the number of the sub-compressed air energy storage systems is two, four, five or six.

[0040] Beneficial effects: The present invention can adjust the number of sub-compression energy storage systems according to specific circumstances so that the pressure of the sub-compression energy storage systems fluctuates within a smaller range, thereby enabling the compressed air energy storage system to operate efficiently and stably. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0042] Figure 1 It is a schematic diagram of the installation of an energy storage system integrating pumped storage and compressed air energy storage according to an embodiment of the present invention;

[0043] Figure 2A schematic diagram of the connection relationship of a sub-compressed air energy storage system according to an embodiment of the present invention;

[0044] Figure 3 for Figure 2 The structural schematic diagram of the gas storage shown;

[0045] Figure 4 A schematic diagram of the connection relationship between adjacent sub-compressed air energy storage systems according to an embodiment of the present invention;

[0046] Figure 5 Schematic diagram of the compression process of the flexible storage device in an embodiment of the present invention;

[0047] Figure 6 Schematic diagram of the expansion process of the flexible storage device in an embodiment of the present invention.

[0048] Description of reference numerals:

[0049] 1. Pumped storage system; 101. First water pipeline; 102. Upper reservoir; 103. Reversible pump turbine; 104. Lower reservoir; 2. Sub-compressed air energy storage system; 201. Second water pipeline; 202. Second gas pipeline; 2021. Gas main pipeline; 2022. Gas branch pipeline; 2023. Three-way valve; 203. First gas pipeline; 204. Compressor; 205. Gas storage reservoir; 2051. Water pipe interface; 2052. Flexible storage device; 206. Expander; 207. First heat exchanger; 2071. Second switch valve; 208. Second heat exchanger; 209. Motor; 210. Generator. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0051] In order to further improve the flexibility of the electric energy storage system, the present invention provides an energy storage system integrating pumped storage and compressed air energy storage.

[0052] Combine the following Figures 1 to 6 , describing an embodiment of the present invention.

[0053] According to an embodiment of the present invention, on the one hand, there is provided an energy storage system integrating pumped storage and compressed air energy storage, comprising: a pumped storage system 1 and a compressed air energy storage system.

[0054] Specifically, the pumped-storage system 1 includes a first water pipeline 101; the compressed air energy storage system includes multiple sub-compressed air energy storage systems 2, and the multiple sub-compressed air energy storage systems 2 are arranged on one side of the pumped-storage system 1. The multiple sub-compressed air energy storage systems 2 are arranged at intervals from high to low, and any sub-compressed air energy storage system 2 is connected to the first water pipeline 101 through the second water pipeline 201.

[0055] The embodiment of the present invention connects the compressed air energy storage system with the pumped storage system 1 through the second transmission pipeline, so that the compressed air energy storage system and the pumped storage system 1 can operate jointly, which improves the capacity of single-form energy storage, enriches the operating conditions of the energy storage system, and broadens the energy storage adjustment range, which is conducive to promoting the development and construction of small and medium-sized pumped storage power stations. In addition, multiple sub-compressed air energy storage systems 2 are arranged from high to low intervals, so that the sub-compressed air energy storage systems 2 at different positions have different pressure levels, thereby realizing the graded energy storage of compressed air potential energy, so that the compressed air energy storage system is more efficient and stable.

[0056] It should be noted that the pumped storage system 1 in this embodiment can be set up in an area with a certain terrain difference, such as a mountain, so as to convert electrical energy into the gravitational potential energy of water for storage or convert the gravitational potential energy of water into electrical energy for release. In addition, when the pumped storage system 1 is set up on a mountain, it is preferred to set the first water pipeline 101 at a position close to the outer surface of the mountain, so as to facilitate the connection between the sub-compressed air energy storage system 2 and the pumped storage system 1, while reducing the length of the first water pipeline 101 and reducing the installation cost.

[0057] In order to ensure that the pressure of each sub-compressed energy storage system fluctuates within a smaller range, the number of sub-compressed air energy storage systems 2 in the compressed air energy storage system can be adjusted according to the terrain difference. Exemplarily, the number of sub-compressed air energy storage systems 2 in the compressed air energy storage system can be two, four, five or six.

[0058] In a specific embodiment, the number of sub-compressed air energy storage systems 2 is four, and the pumped storage system 1 is arranged on a mountain with a height difference of 900 meters. Furthermore, since the pumped storage system 1 and the sub-compressed air energy storage system 2 are connected to the first water pipeline 101 through the second water pipeline 201, the storage pressure in the sub-compressed air energy storage system 2 will be determined by the water head height of the second water pipeline 201, so the storage pressure in the sub-compressed air energy storage system 2 can be changed by adjusting the water head height. In this embodiment, from high to low, the storage pressures of the four sub-compressed air energy storage systems 2 are about 3MPa, about 5MPa, about 7MPa, and about 9MPa, respectively. Such a setting can realize the hierarchical storage of high-pressure gas and ensure the efficient operation of the compressed air energy storage system.

[0059] According to one embodiment of the present invention, the sub-compressed air energy storage system 2 includes a compressor unit, a gas storage reservoir 205 and an expander unit connected in sequence through a first gas transmission pipeline 203, wherein the gas storage reservoir 205 is connected to the pumped storage system 1 through a second water transmission pipeline 201.

[0060] The embodiment of the present invention connects the compressor unit, the gas storage reservoir 205 and the expander unit in sequence by using the first gas transmission pipeline 203, so that the compressed air energy storage system can complete the storage or release of electric energy according to actual needs. In addition, the gas storage reservoir 205 is connected to the pumped storage system 1 through the second water transmission pipeline 201, so that the water in the pumped storage system 1 can freely enter and exit the gas storage reservoir 205, thereby reducing the pressure change range in the gas storage reservoir 205 during the storage or release of electric energy by the compressed air energy storage system, thereby improving the stability of the operation of the compressed air energy storage system and the utilization rate of the volume of the gas storage reservoir 205.

[0061] It should be noted that in the embodiment of the present invention, the working pressure of the sub-compressed air energy storage system 2 increases from high to low. Such an arrangement can reduce the pressure difference between the compressor unit and the expander unit in the same sub-compressed air energy storage system 2, so that the pressure in the gas storage reservoir 205 changes only within a small range, thereby enabling the compressed air energy storage system to operate efficiently and stably.

[0062] According to one embodiment of the present invention, the gas storage reservoir 205 is provided with a water pipe interface 2051 connected to the second water pipeline 201 , and the water pipe interface 2051 is arranged at one end close to the bottom of the gas storage reservoir 205 .

[0063] The embodiment of the present invention arranges the water pipe interface 2051 at one end close to the bottom of the gas storage reservoir 205, so that the water in the pumped storage system 1 can still freely enter and exit the gas storage reservoir 205 while reducing the number of other equipment used, so that the real-time pressure in the gas storage reservoir 205 can be adjusted by water flow, and the pressure variation range in the gas storage reservoir 205 can be reduced, so that all the air stored in the gas storage reservoir 205 can be used for expansion power generation, thereby improving the energy conversion efficiency of the compressed air energy storage system.

[0064] According to one embodiment of the present invention, a flexible storage device 2052 is provided in the gas storage reservoir 205, and the flexible storage device 2052 is connected to the water pipe interface 2051. The embodiment of the present invention can separate the high-pressure gas in the compressed air energy storage system from the water phase entering the gas storage reservoir 205 by providing the flexible storage device 2052 in the gas storage reservoir 205, thereby avoiding direct contact between the high-pressure gas and the water, thereby reducing the moisture content in the high-pressure gas, and at the same time, can reduce the probability of rusting of equipment and pipelines, and increase the life of the system.

[0065] It should be noted that the flexible storage device 2052 can be a flexible storage bag made of one or more of polyethylene, polyester, polypropylene or nylon.

[0066] According to one embodiment of the present invention, adjacent sub-compressed air energy storage systems 2 are connected via a second air transmission pipeline 202 .

[0067] The embodiment of the present invention connects adjacent sub-compressed air energy storage systems 2 through a second gas transmission pipeline 202, so that high-pressure gas can flow freely between adjacent sub-compressed air energy storage systems 2, thereby improving the energy storage efficiency of the compressed air energy storage system and reducing energy loss. It can be understood that when the energy storage capacity of one of the sub-compressed air energy storage systems 2 is insufficient, additional compressed gas can be obtained from the sub-compressed air energy storage system 2 located above to meet the energy storage demand. Conversely, when a sub-compressed air energy storage system 2 has excess energy, the excess compressed gas can also be transmitted to the sub-compressed air energy storage system 2 located above for storage, thereby increasing the electrical energy storage capacity and electrical energy release capacity of the sub-compressed air energy storage system 2.

[0068] According to one embodiment of the present invention, the second gas transmission pipeline 202 includes a gas transmission main pipe 2021 and two gas transmission branches 2022. One end of the gas transmission main pipe 2021 is connected to the gas storage reservoir 205 in the sub-compressed air energy storage system 2 located above, and the other end is connected to the two gas transmission branches 2022 through a three-way valve 2023. The two gas transmission branches 2022 are respectively connected to the air inlet of the compressor unit and the air outlet of the expansion unit in the sub-compressed air energy storage system 2 located below.

[0069] The embodiment of the present invention can connect the gas storage reservoir 205 in the upper sub-compressed air energy storage system 2 with the compressor unit and the expander unit in the lower sub-compressed air energy storage system 2 by setting a gas main pipe 2021 and two gas branch pipes 2022, and can also make the gas pipeline more compact in layout and reduce the occupied space. In addition, by setting a three-way valve 2023 between the gas main pipe 2021 and the two gas branch pipes 2022, the second gas pipeline 202 can connect one of the two gas branch pipes 2022 with the gas main pipe 2021 according to demand during the process of storing or releasing electric energy in the compressed air energy storage system, and realize graded energy storage and energy release in the compression process and the expansion process respectively, which improves the efficiency of the compressed air energy storage system on the one hand, and ensures the stability of the operation of the compressed air energy storage system on the other hand.

[0070] According to an embodiment of the present invention, the three-way valve 2023 is one of a T-type three-way valve, an L-type three-way valve or a straight-through three-way valve. The embodiment of the present invention can connect one of the two gas transmission branches 2022 with the gas transmission main pipe 2021 according to demand by adopting any of the above three-way valves 2023, which can improve the energy storage capacity of the compressed air energy storage system on the one hand, and make the compressed air energy storage system flexibly applicable to various working conditions on the other hand.

[0071] According to one embodiment of the present invention, two second gas pipelines 202 are provided between adjacent sub-compressed air energy storage systems 2, wherein the two ends of one second gas pipeline 202 are respectively connected to the gas storage reservoir 205 in the upper sub-compressed air energy storage system 2 and the air inlet of the compressor unit in the lower sub-compressed air energy storage system 2, and the two ends of the other second gas pipeline 202 are respectively connected to the gas storage reservoir 205 in the upper sub-compressed air energy storage system 2 and the air outlet of the expansion unit in the lower sub-compressed air energy storage system 2, and the two second gas pipelines 202 are respectively provided with a first switch valve.

[0072] The embodiment of the present invention sets a second gas pipeline 202 between the gas storage reservoir 205 in the upper sub-compressed air energy storage system 2 and the compressor unit and the expander unit in the lower sub-compressed air energy storage system 2, so that the compressed air energy storage system can store or release large amounts of electrical energy, thereby balancing the load on the power grid and avoiding overload or power shortage.

[0073] According to an embodiment of the present invention, the first switch valve is a one-way valve. The embodiment of the present invention ensures that the high-pressure gas flows in one direction by setting the first switch valve as a one-way valve, avoids the problem of high-pressure gas backflow, and improves the working efficiency and stability of the system.

[0074] According to one embodiment of the present invention, the sub-compressed air energy storage system 2 further includes a first heat exchanger 207, which is connected to the compressor unit and the gas storage reservoir 205 through the first gas transmission pipeline 203. Since a large amount of heat is usually generated when the gas is compressed by the compressor unit, the embodiment of the present invention sets the first heat exchanger 207 between the compressor unit and the gas storage reservoir 205, so that the sub-compressed air energy storage system 2 can store the heat generated when the gas is compressed, thereby improving the utilization rate of energy.

[0075] According to one embodiment of the present invention, the sub-compressed air energy storage system 2 also includes a second heat exchanger 208, which is connected to the expander unit and the gas storage reservoir 205 through the first gas transmission pipeline 203, and a second switch valve 2071 is provided between the first heat exchanger 207 and the second heat exchanger 208 and the gas storage reservoir 205. Since the gas needs to absorb heat during the expansion of the expander unit. Therefore, in an embodiment of the present invention, the second heat exchanger 208 is arranged between the expander unit and the gas storage reservoir 205, and the heat stored in the first heat exchanger 207 can be used to heat the gas in the expander unit. Such an arrangement can increase the output power of the expander unit and improve the energy storage efficiency of the system on the one hand, and reduce the use of traditional fuel on the other hand.

[0076] According to one embodiment of the present invention, the pumped storage system 1 further includes an upper reservoir 102, a reversible pump turbine 103 and a lower reservoir 104 which are sequentially connected via a first water transmission pipeline 101. The embodiment of the present invention can not only convert electrical energy into the gravitational potential energy of water by setting the reversible pump turbine 103, thereby realizing the storage of electrical energy during the low-peak period of electricity consumption; it can also reconvert the gravitational potential energy of water into electrical energy, thereby realizing the release of electrical energy to meet the demand for electrical energy during the peak period of electricity consumption. At the same time, by setting the reversible pump turbine 103, the number of devices used in the pumped storage system 1 can be reduced, thereby reducing the complexity of the pumped storage system 1.

[0077] According to one embodiment of the present invention, the compressor unit includes a motor 209 and a compressor 204 connected to the motor 209. The embodiment of the present invention can provide better power output and speed control by using the motor 209 as the power source of the compressor 204 to adapt to different operating requirements.

[0078] According to one embodiment of the present invention, the expander unit includes a generator 210 and an expander 206 connected to the generator 210. The embodiment of the present invention can release the electric energy previously stored in the compressed air energy storage system through the cooperation of the expander 206 and the generator 210, thereby meeting the user's demand for electric energy.

[0079] According to one embodiment of the present invention, the gas storage 205 is a combination of one or more of a gas storage tank, a pipeline steel bundle gas storage 205, an underground salt cavern, an artificial underground chamber, and a tunnel. The embodiment of the present invention can meet different gas storage needs by selecting different forms of gas storage 205, while better improving the efficiency and stability of gas storage.

[0080] According to one embodiment of the present invention, in this embodiment, the gas input into the air inlet of the compressor unit can be air or carbon dioxide. Considering that carbon dioxide has a high density and a low viscosity in a supercritical state (7.38MPa, 31°C), it is easier to compress it at this time. Therefore, in a specific embodiment, the gas storage reservoir 205 in the sub-compressed air energy storage system 2 with carbon dioxide as the working fluid is arranged near the lower reservoir 104 of the pumped storage system 1 (i.e., the lower end of the mountain), and the pressure in the gas storage reservoir 205 is above the critical pressure of carbon dioxide. Such an arrangement can save space in the gas storage reservoir 205 while making the compressed carbon dioxide in a supercritical state.

[0081] In addition, as the most mature large-scale energy storage technology at present, pumped storage (pumped storage system 1) has a variety of operation modes compared to other new energy storage methods, such as power grid operation mode, leasing operation mode and independent operation mode, while the bidding mechanism of compressed air energy storage system is still unclear. Therefore, in the present invention, by integrating the pumped storage system 1 with the compressed air energy storage system, it is possible to achieve complementarity between different technologies and effectively improve the efficiency of the energy storage system. At the same time, the pumped storage system 1 can also be used to improve the market bidding mechanism of the compressed air energy storage system to meet the needs of commercial operation.

[0082] Although the present invention has been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Such modifications and variations shall all fall within the scope defined by the appended claims.

Claims

1. An energy storage system integrating pumped storage and compressed air energy storage, characterized in that: include: A pumped storage system (1) comprises a first water transmission pipeline (101); A compressed air energy storage system, comprising a plurality of sub-compressed air energy storage systems (2), wherein the plurality of sub-compressed air energy storage systems (2) are arranged on one side of the pumped storage system (1), the plurality of sub-compressed air energy storage systems (2) are arranged in intervals from high to low, and any of the sub-compressed air energy storage systems (2) is connected to the first water pipeline (101) via a second water pipeline (201); The sub-compressed air energy storage system (2) comprises a compressor unit, a gas storage reservoir (205), and an expander unit which are sequentially connected via a first gas transmission pipeline (203), wherein the gas storage reservoir (205) is connected to the pumped storage system (1) via a second water transmission pipeline (201); Adjacent sub-compressed air energy storage systems (2) are connected via a second air transmission pipeline (202); The second gas transmission pipeline (202) comprises a gas transmission main pipe (2021) and two gas transmission branch pipes (2022); one end of the gas transmission main pipe (2021) is connected to the gas storage reservoir (205) in the sub-compressed air energy storage system (2) located above, and the other end is respectively connected to the two gas transmission branch pipes (2022) via a three-way valve (2023); the two gas transmission branch pipes (2022) are respectively connected to the air inlet of the compressor unit and the air outlet of the expander unit in the sub-compressed air energy storage system (2) located below.

2. The energy storage system integrating pumped storage and compressed air energy storage according to claim 1, characterized in that: The gas storage reservoir (205) is provided with a water pipe interface (2051) connected to the second water delivery pipeline (201), and the water pipe interface (2051) is arranged at one end close to the bottom of the gas storage reservoir (205).

3. The energy storage system integrating pumped storage and compressed air energy storage according to claim 2 is characterized in that: A flexible storage device (2052) is provided in the gas storage reservoir (205), and the flexible storage device (2052) is connected to the water pipe interface (2051).

4. The energy storage system integrating pumped storage and compressed air energy storage according to claim 1, characterized in that: The three-way valve (2023) is one of a T-type three-way valve, an L-type three-way valve or a straight-type three-way valve.

5. The energy storage system integrating pumped storage and compressed air energy storage according to claim 1, characterized in that: Two second gas transmission pipelines (202) are provided between adjacent sub-compressed air energy storage systems (2), wherein two ends of one of the second gas transmission pipelines (202) are respectively connected to a gas storage reservoir (205) in the sub-compressed air energy storage system (2) located above and an air inlet of a compressor unit in the sub-compressed air energy storage system (2) located below, and two ends of the other second gas transmission pipeline (202) are respectively connected to a gas storage reservoir (205) in the sub-compressed air energy storage system (2) located above and an air outlet of an expander unit in the sub-compressed air energy storage system (2) located below, and first switch valves are respectively provided on the two second gas transmission pipelines (202).

6. The energy storage system integrating pumped storage and compressed air energy storage according to claim 5, characterized in that: The first switch valve is a one-way valve.

7. The energy storage system integrating pumped storage and compressed air energy storage according to claim 1, characterized in that: The sub-compressed air energy storage system (2) further comprises a first heat exchanger (207), wherein the first heat exchanger (207) is respectively connected to the compressor unit and the gas storage reservoir (205) via the first gas transmission pipeline (203).

8. The energy storage system integrating pumped storage and compressed air energy storage according to claim 7, characterized in that: The sub-compressed air energy storage system (2) further comprises a second heat exchanger (208), the second heat exchanger (208) being connected to the expander unit and the gas storage reservoir (205) respectively via the first gas transmission pipeline (203), and a second switch valve (2071) being provided between the first heat exchanger (207) and the second heat exchanger (208) and the gas storage reservoir (205), respectively.

9. The energy storage system integrating pumped storage and compressed air energy storage according to any one of claims 1 to 8, characterized in that: The pumped storage system (1) also includes an upper reservoir (102), a reversible pump turbine (103), and a lower reservoir (104) which are sequentially connected via the first water transmission pipeline (101).

10. The energy storage system integrating pumped storage and compressed air energy storage according to any one of claims 1 to 8, characterized in that: The compressor unit comprises an electric motor (209) and a compressor (204) connected to the electric motor (209).

11. The energy storage system integrating pumped storage and compressed air energy storage according to any one of claims 1 to 8, characterized in that: The expander unit comprises a generator (210) and an expander (206) connected to the generator (210).

12. The energy storage system integrating pumped storage and compressed air energy storage according to any one of claims 1 to 8, characterized in that: The gas storage (205) is a combination of one or more of a gas storage tank, a pipeline steel bundle gas storage (205), an underground salt cavern, an artificial underground chamber, and a tunnel.

13. The energy storage system integrating pumped storage and compressed air energy storage according to any one of claims 1 to 8, characterized in that: The gas in the air inlet of the compressor unit is air or carbon dioxide.

14. The energy storage system integrating pumped storage and compressed air energy storage according to any one of claims 1 to 8, characterized in that: The number of the sub-compressed air energy storage systems (2) is two, four, five or six.

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