Underground energy storage device system and method using compressed air

Abstract

The invention provides an underground energy storage device system and method utilizing compressed air, the underground energy storage device system comprises an air compression unit, a working medium storage unit, an energy storage unit and a power generation unit, and the energy storage unit is connected with the air compression unit, the working medium storage unit and the power generation unit; the energy storage unit is buried underground; the air compression unit is used for injecting compressed air into the energy storage unit; the working medium storage unit is used for providing a transduction medium for the energy storage unit, and compressed air injected into the energy storage unit converts the transduction medium into a high-pressure medium; the power generation unit is further connected with the working medium storage unit, and the high-pressure medium in the energy storage unit enters the power generation unit to be converted into a low-pressure medium and flows into the working medium storage unit. Energy is stored by compressing air through hydraulic power, the stored air pressure is high, the energy storage density is large, and the overall energy conversion rate reaches 90% or above.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy storage, and relates to an underground energy storage device system and method using compressed air. Background Art

[0002] At present, the energy storage field mainly includes battery energy storage, compressed air energy storage and pumped storage. Battery energy storage is relatively flexible in scale and is mainly used for electrical energy storage. Compressed air mainly stores electrical energy as physical mechanical energy. Pumped storage uses gravity energy storage and can be used for the conversion and storage of electrical energy and mechanical energy. Battery energy storage has high manufacturing costs and large investments, and is greatly affected by ambient temperature and has rapid functional decay. Compressed air energy storage requires a large pressure space volume, which also increases engineering difficulty and operating costs. Compared with battery energy storage and compressed air energy storage, pumped storage has a large capacity, mature equipment technology, and high efficiency, and is widely used in various energy storage scenarios. However, pumped storage has high requirements for the height difference and geological conditions of the application site. In addition, the existing pumped storage has high energy consumption, which increases the overall operating cost and hinders its large-scale application.

[0003] Therefore, it is very important to reduce the operating cost of energy storage while ensuring high conversion efficiency. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide an underground energy storage device system and method using compressed air, which stores electrical energy as molecular energy of compressed air through hydraulically compressed air energy storage and high-pressure air-driven hydroelectric power generation, thereby increasing the energy storage density and greatly improving the energy conversion rate, achieving isothermal compression of air and reducing energy consumption.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides an underground energy storage device system utilizing compressed air, the underground energy storage device system comprising an air compression unit, a working fluid storage unit, an energy storage unit and a power generation unit, the energy storage unit being respectively connected to the air compression unit, the working fluid storage unit and the power generation unit; the energy storage unit being buried underground; the air compression unit being used to inject compressed air into the energy storage unit; the working fluid storage unit being used to provide a transducing medium to the energy storage unit, the compressed air injected into the energy storage unit converts the transducing medium into a high-pressure medium for storage; the power generation unit is also connected to the working fluid storage unit, the high-pressure medium in the energy storage unit enters the power generation unit and is converted into a low-pressure medium, and flows into the working fluid storage unit.

[0007] The present invention utilizes a transducer medium to compress air for energy storage, and then utilizes the compressed air to push the transducer medium to release energy for power generation, thereby realizing isothermal air compression and expansion, reducing energy consumption, greatly improving energy storage density, and achieving high-efficiency conversion. The underground energy storage design adopted reduces the floor space occupied, has high safety, and low cost.

[0008] As a preferred technical solution of the present invention, the air compression unit includes an air supply pipeline, an air pressurizing device and a plurality of air supply branches.

[0009] The air supply pipeline is connected to the inlet end of the air pressurizing device.

[0010] A plurality of the air supply branches are arranged in parallel, one end of the air supply branch is connected to the outlet end of the air pressurizing device, and the other end is connected to the energy storage unit.

[0011] At least one first regulating valve is arranged on the gas supply branch line.

[0012] As a preferred technical solution of the present invention, the energy storage unit includes a plurality of first sealed pressure tubes and a plurality of second sealed pressure tubes buried underground.

[0013] A plurality of first sealed pressure tubes are arranged in parallel, the gas supply branch extends into the bottom of the inner cavity of the first sealed pressure tube, and the gas supply branch is also connected to the tops of a plurality of second sealed pressure tubes through gas supply sub-branches.

[0014] A plurality of second sealed pressure tubes are arranged in parallel, and the second sealed pressure tubes are respectively connected to the working fluid storage unit and the power generation unit through medium pipelines, and the medium pipelines extend into the bottom of the inner cavity of the second sealed pressure tubes.

[0015] At least one second regulating valve is arranged on the medium pipeline.

[0016] At least one third regulating valve is arranged on the gas supply secondary branch.

[0017] The present invention uses a buried pressure tube to store energy, which improves the safety factor of the pressure vessel, reduces the cost of pressure equipment, and is also conducive to the realization of high pressure. When storing energy, the energy conversion medium is used to directly compress the air, which reduces the heat loss during the air compression process, maintains a constant temperature, and saves energy consumption. When releasing energy, the air is used to directly push the energy conversion medium to achieve full contact and heat exchange, which is conducive to the constant temperature of the air during expansion, maintains the expansion potential energy, maintains the efficient operation of the system, and can also dynamically switch and adjust the energy storage and release states.

[0018] Preferably, an exhaust assembly is also provided on the top of the second sealed pressure tube, and the exhaust assembly is used to exhaust the air in the second sealed pressure tube.

[0019] As a preferred technical solution of the present invention, the power generation unit includes a primary hydroelectric power generation device, a buffer tank and a secondary hydroelectric power generation device which are connected in sequence.

[0020] The buffer tank is buried underground.

[0021] The inlet end and the outlet end of the first-level hydroelectric power generation device are respectively provided with a feed pipeline and a first discharge pipeline, the feed pipeline is respectively connected to a plurality of the medium pipelines, and the first discharge pipeline is connected to the top of the buffer tank.

[0022] The buffer tank is connected to the inlet end of the secondary hydroelectric power generation device through a second discharge pipeline, and one end of the second discharge pipeline away from the secondary hydroelectric power generation device extends into the bottom of the inner cavity of the buffer tank.

[0023] A return pipeline is provided at the outlet end of the secondary hydroelectric power generation device, and one end of the return pipeline away from the secondary hydroelectric power generation device is connected to the working medium storage unit.

[0024] In the present invention, the first-stage hydroelectric power generation device performs high-pressure head hydroelectric power generation, and the second-stage hydroelectric power generation device performs low-pressure head hydroelectric power generation, which fully releases energy, achieves a power generation efficiency of more than 90%, and greatly improves the energy storage density per unit volume.

[0025] As a preferred technical solution of the present invention, the power generation unit includes a pressure regulating device and a hydroelectric power generation device; the inlet end and the outlet end of the pressure regulating device are respectively provided with a feed pipeline and a discharge pipeline, the feed pipeline is respectively connected to a plurality of the medium pipelines, and the discharge pipeline is connected to the hydroelectric power generation device; the outlet end of the hydroelectric power generation device is provided with a return pipeline, and the end of the return pipeline away from the hydroelectric power generation device is connected to the working fluid storage unit.

[0026] As a preferred technical solution of the present invention, the working fluid storage unit includes a medium storage device and a feed pipeline, the medium storage device is connected to the power generation unit, one end of the feed pipeline is connected to the medium storage device, and the other end is connected to the medium pipeline through a feed secondary branch.

[0027] A driving pump is arranged on the feeding pipeline.

[0028] At least one fourth regulating valve is arranged on the secondary feeding branch.

[0029] In a second aspect, the present invention provides an underground energy storage method using compressed air. The underground energy storage method adopts the underground energy storage device system using compressed air described in the first aspect. The underground energy storage method includes an energy storage process and an energy release process.

[0030] The energy storage process includes: connecting an air compression unit with an energy storage unit, compressing air with the air compression unit, and sending the compressed air into the energy storage unit until the air in the energy storage unit reaches a first preset pressure, closing the air compression unit, and connecting a working fluid storage unit with the energy storage unit, injecting a transducing medium into the energy storage unit with the working fluid storage unit, and the transducing medium compressing the air in the energy storage unit to reach a second preset pressure for energy storage.

[0031] The energy release process includes: connecting the energy storage unit and the power generation unit so that the compressed air in the energy storage unit expands, the transducing medium is converted into a high-pressure medium and enters the power generation unit, the power generation unit performs work to generate electricity to release energy, and the high-pressure medium is converted into a low-pressure medium and flows to the working fluid storage unit.

[0032] The present invention utilizes the full contact between the transducer medium and the compressed air during energy storage, compressing the air to a high pressure for storage, and utilizes the high-pressure air to push the transducer medium into the power generation unit to perform work and generate electricity for release during energy release. After the work is completed, the low-pressure medium enters the next energy storage cycle, thereby improving the energy storage density and achieving high-efficiency power generation.

[0033] As a preferred technical solution of the present invention, during the energy storage process, the compressed air provided by the air compression unit enters the first sealed pressure tube and the second sealed pressure tube respectively, so that the pressure of the first sealed pressure tube and the second sealed pressure tube reaches a first preset pressure; the transducing medium provided by the working fluid storage unit enters the second sealed pressure tube, and the compressed air in the second sealed pressure tube is pressed into the first sealed pressure tube until the second sealed pressure tube is filled with the transducing medium and the pressure in the first sealed pressure tube reaches the second preset pressure, thereby completing the energy storage; the first sealed pressure tube and the second sealed pressure tube independently perform heat exchange with the underground soil, so that the compressed air maintains a constant temperature.

[0034] Preferably, the transducing medium is water.

[0035] The present invention arranges pressure pipes underground so that the sealed pressure pipe wall and the surrounding soil can fully exchange heat. The compressed air is compressed to high pressure under a nearly constant temperature state, thereby achieving isothermal compression and isothermal expansion and effectively reducing energy consumption.

[0036] As a preferred technical solution of the present invention, the energy release process includes primary energy release and secondary energy release performed sequentially.

[0037] In the first-stage energy release, compressed air pushes the high-pressure medium into the first-stage hydroelectric power generation device, thereby driving the first-stage hydroelectric power generation device to generate power at high pressure. The high-pressure medium is depressurized once and flows into the buffer tank for storage.

[0038] In the secondary energy release, the high-pressure medium in the buffer tank that has been depressurized once enters the secondary hydroelectric power generation device, thereby driving the secondary hydroelectric power generation device to generate power at low pressure. The high-pressure medium is depressurized for a second time, and after the pressure reaches atmospheric pressure, it flows into the working fluid storage unit for storage.

[0039] The present invention adopts two-stage energy release to realize high-pressure hydropower generation and low-pressure hydropower generation in sequence, which effectively improves the energy conversion efficiency and makes the power generation efficiency exceed 90%.

[0040] As a preferred technical solution of the present invention, the energy release process includes: compressed air pushes the high-pressure medium into the pressure regulating device, regulates the pressure of the high-pressure medium, and then sends it into the hydroelectric power generation device to perform work and generate electricity, so that the pressure of the high-pressure medium reaches atmospheric pressure and then flows into the working fluid storage unit for storage.

[0041] The present invention pre-adjusts the pressure of the high-pressure medium during the energy release process, so that it can safely drive the hydropower generation device to generate power, thereby greatly improving the energy conversion effect.

[0042] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The present invention provides an underground energy storage device system and method using compressed air, which adopts an underground layout structure to achieve isothermal compression and expansion, reduce energy consumption, and have high safety. It stores energy through hydraulic compression of air, increases the storage air pressure, has a high energy storage density, and an overall energy conversion rate of more than 90%, thereby achieving high-efficiency power generation. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A schematic diagram of the structure of an underground energy storage device system using compressed air provided in Example 1 of the present invention;

[0046] Figure 2 A schematic diagram of the structure of an underground energy storage device system using compressed air provided in Example 2 of the present invention.

[0047] Among them, 1-first sealed pressure pipe; 2-second sealed pressure pipe; 3-air supply pipeline; 4-air pressurizing device; 5-air supply branch; 6-medium pipeline; 7-first-level hydroelectric power generation device; 8-buffer tank; 9-second-level hydroelectric power generation device; 10-feed pipeline; 11-first discharge pipeline; 12-second discharge pipeline; 13-reflux pipeline; 14-medium storage device; 15-feed pipeline; 16-driving pump; 17-feed sub-branch; 18-air supply sub-branch; 19-pressure regulating device; 20-hydroelectric power generation device; 21-discharge pipeline. DETAILED DESCRIPTION

[0048] It should be understood that, in the description of the present invention, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are 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, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0049] It should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" 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 a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0050] Those skilled in the art should understand that the present invention necessarily includes necessary pipelines, conventional valves and general pump equipment for realizing a complete process, but the above content does not belong to the main inventive point of the present invention. Those skilled in the art can add layouts on their own based on the process flow and equipment structure selection, and the present invention does not make special requirements and specific limitations on this.

[0051] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0052] In a specific embodiment, the present invention provides an underground energy storage device system using compressed air, comprising an air compression unit, a working fluid storage unit, an energy storage unit and a power generation unit, wherein the energy storage unit is respectively connected to the air compression unit, the working fluid storage unit and the power generation unit; the energy storage unit is buried underground; the air compression unit is used to inject compressed air into the energy storage unit; the working fluid storage unit is used to provide a transduction medium to the energy storage unit, and the compressed air injected into the energy storage unit converts the transduction medium into a high-pressure medium; the power generation unit is also connected to the working fluid storage unit, and the high-pressure medium in the energy storage unit enters the power generation unit and is converted into a low-pressure medium, and flows into the working fluid storage unit.

[0053] In some embodiments, the air compression unit includes an air supply pipeline, an air pressurizing device and several air supply branches. The air supply pipeline is connected to the inlet end of the air pressurizing device to input air into the air pressurizing device. The air pressurizing device is arranged on the ground and is used to compress air to obtain compressed air. The present invention does not specifically limit the structure and size of the air pressurizing device. Any pressurizing device commonly used by those skilled in the art can be used, and the size of the device can be adjusted according to the amount of energy storage air, for example, it can be a fan. Several air supply branches are arranged in parallel, one end of the air supply branch is connected to the outlet end of the air pressurizing device, and the other end is connected to the energy storage unit. The compressed air in the air pressurizing device enters the energy storage unit from several air supply branches for storage. At least one first regulating valve is arranged on the air supply branch, which is used to connect the air compression unit and the energy storage unit, and can adjust the start and stop and opening of the input compressed air. The first regulating valve can be a manual valve, which can be opened and closed and adjusted manually by the operator; it can also be a solenoid valve or an electric valve, and the operator can achieve remote control through the commonly used software and hardware and electromechanical control technology in this field.

[0054] In some embodiments, the energy storage unit includes a plurality of first sealed pressure pipes and a plurality of second sealed pressure pipes buried underground. The plurality of first sealed pressure pipes are arranged in parallel, the air supply branch extends into the bottom of the inner cavity of the first sealed pressure pipe, and the air supply branch is also connected to the tops of the plurality of second sealed pressure pipes through the air supply sub-branch. The compressed air of the air pressurizing device enters the first sealed pressure pipe from the air supply branch, and enters the second sealed pressure pipe from the air supply sub-branch to maintain the air pressure in the energy storage unit. The plurality of second sealed pressure pipes are arranged in parallel, and the second sealed pressure pipes are respectively connected to the working fluid storage unit and the power generation unit through the medium pipeline, and the medium pipeline extends into the bottom of the inner cavity of the second sealed pressure pipe. The working fluid storage unit is connected to the energy storage unit, and when the power generation unit is turned off, the energy conversion medium enters the second sealed pressure pipe from the medium pipeline, compressing the air in the second sealed pressure pipe to the first sealed pressure pipe for high-pressure air energy storage. The heat generated by air compression during the process is dissipated through heat exchange with the transducing medium and the outer wall of the pressure tube, and the air is kept at an approximately constant temperature. The power generation unit is connected to the energy storage unit, and when the working fluid storage unit is closed, the high-pressure medium in the second sealed pressure tube enters the power generation unit through the medium pipeline to perform work and generate electricity to release energy. At least one second regulating valve is arranged on the medium pipeline to control the circulation of the transducing medium between the power generation unit and the second sealed pressure tube, including but not limited to a manual valve, a solenoid valve or an electric valve. At least one third regulating valve is arranged on the air supply secondary branch to control the circulation of air between the first sealed pressure tube and the second sealed pressure tube, including but not limited to a manual valve, a solenoid valve or an electric valve. Specifically, the air supply secondary branch includes a main pipe and several branch pipes arranged in parallel on the main pipe, and the main pipe is connected to the air supply branch through a part of the branch pipe, and is connected to the top of the second sealed pressure tube through another part of the branch pipe. During the application process, the first regulating valve and the third regulating valve are opened, and the compressed air in the air pressurizing device is respectively sent into a plurality of first sealed pressure pipes and a plurality of second sealed pressure pipes. When the pressure reaches the preset pressure, the first regulating valve is closed, and the third regulating valve is kept open. After the transducing medium is injected into the second sealed pressure pipe, the air in the second sealed pressure pipe is compressed and returned to the first sealed pressure pipe for storage. The operator can manually adjust the second regulating valve and the third regulating valve, and can also realize remote control through the commonly used software, hardware and electromechanical control technology in this field.

[0055] Furthermore, the top of the second sealed pressure pipe is also provided with an exhaust assembly, which is used to exhaust the air in the second sealed pressure pipe. The present invention provides necessary connecting pipelines and safety valves for the exhaust assembly, which is not specifically limited in the present invention, and those skilled in the art need to reasonably adjust, add or delete according to actual production needs.

[0056] In some embodiments, the present invention provides the following two configuration schemes of power generation units based on different energy release processes:

[0057] (1) The power generation unit includes a primary hydroelectric power generation device, a buffer tank and a secondary hydroelectric power generation device connected in sequence. The buffer tank is buried underground. The inlet and outlet ends of the primary hydroelectric power generation device are respectively provided with a feed pipeline and a first discharge pipeline, the feed pipelines are respectively connected to a plurality of the medium pipelines, and the first discharge pipeline is connected to the top of the buffer tank. The buffer tank is connected to the inlet end of the secondary hydroelectric power generation device through a second discharge pipeline, and one end of the second discharge pipeline away from the secondary hydroelectric power generation device extends into the bottom of the inner cavity of the buffer tank. The outlet end of the secondary hydroelectric power generation device is provided with a return pipeline, and one end of the return pipeline away from the secondary hydroelectric power generation device is connected to the working fluid storage unit. In the present invention, the high-pressure medium in the second sealed pressure tube is introduced into the feed pipeline through the medium pipeline, and enters the first-level hydroelectric power generation device to perform high-pressure hydraulic work and generate electricity. After the work is completed, it is discharged from the first discharge pipeline into the buffer tank for accumulation. At this time, the pressure of the high-pressure medium is reduced, and then it enters the second-level hydroelectric power generation device through the second discharge pipeline to perform low-pressure hydraulic work and generate electricity. After the work is completed, the pressure of the high-pressure medium is further reduced to atmospheric pressure, and flows into the working fluid storage unit through the reflux pipeline to enter the next energy storage cycle, completing a power generation efficiency of more than 90%, and greatly improving the energy storage density per unit volume.

[0058] (2) The power generation unit includes a pressure regulating device and a hydroelectric power generation device; the inlet and outlet ends of the pressure regulating device are respectively provided with a feed pipeline and a discharge pipeline, the feed pipeline is respectively connected to a plurality of the medium pipelines, and the discharge pipeline is connected to the hydroelectric power generation device; the outlet end of the hydroelectric power generation device is provided with a return pipeline, and the end of the return pipeline away from the hydroelectric power generation device is connected to the working medium storage unit. The present invention does not specifically limit the structure of the pressure regulating device, and any pressure regulating device structure known to those skilled in the art as long as it can achieve the pressure regulation of the high-pressure medium can be used in the present invention.

[0059] In some embodiments, the working fluid storage unit includes a medium storage device and a feed pipeline, wherein the medium storage device is connected to the power generation unit, one end of the feed pipeline is connected to the medium storage device, and the other end is connected to the medium pipeline through a feed sub-branch. A driving pump is provided on the feed pipeline. At least one fourth regulating valve is provided on the feed sub-branch. Under the action of the driving pump, the energy conversion medium in the medium storage device of the present invention passes through the feed pipeline and enters several medium pipelines inserted into the second sealed pressure pipe respectively, and gradually accumulates in the second sealed pressure pipe until the second sealed pressure pipe is filled. At this time, the air pressure in the first sealed pressure pipe reaches the preset pressure, and the energy storage process is completed. The pressure of the low-pressure medium that has finished working and generating electricity in the power generation unit reaches atmospheric pressure, and flows back to the medium storage device for storage again, in preparation for the next energy storage cycle.

[0060] In another specific embodiment, the present invention provides an underground energy storage method using compressed air, wherein the underground energy storage method uses an underground energy storage device system using compressed air as described in a specific embodiment, and the underground energy storage method includes an energy storage process and an energy release process;

[0061] The energy storage process includes: connecting an air compression unit with an energy storage unit, compressing air with the air compression unit, and sending the compressed air into the energy storage unit until the air in the energy storage unit reaches a first preset pressure, closing the air compression unit, and connecting a working fluid storage unit with the energy storage unit, injecting a transducing medium into the energy storage unit with the working fluid storage unit, and the transducing medium compressing the air in the energy storage unit to reach a second preset pressure for energy storage;

[0062] The energy release process includes: connecting the energy storage unit and the power generation unit so that the compressed air in the energy storage unit expands, the transducing medium is converted into a high-pressure medium and enters the power generation unit, the power generation unit performs work to generate electricity to release energy, and the high-pressure medium is converted into a low-pressure medium and flows to the working fluid storage unit.

[0063] Specifically, during the energy storage process, the compressed air provided by the air compression unit enters the first sealed pressure tube and the second sealed pressure tube respectively, so that the pressure of the first sealed pressure tube and the second sealed pressure tube reaches the first preset pressure; the transducing medium provided by the working fluid storage unit enters the second sealed pressure tube, and the compressed air in the second sealed pressure tube is pressed into the first sealed pressure tube until the second sealed pressure tube is filled with the transducing medium, and the pressure in the first sealed pressure tube reaches the second preset pressure, and energy storage is completed; the first sealed pressure tube and the second sealed pressure tube independently exchange heat with the underground soil to keep the compressed air at a constant temperature. Preferably, the transducing medium is water. The present invention does not specifically limit the first preset pressure and the second preset pressure, and those skilled in the art can adjust them according to the actual energy storage scale.

[0064] In some embodiments, the energy release process includes primary energy release and secondary energy release performed sequentially.

[0065] In the first-stage energy release, compressed air pushes the high-pressure medium into the first-stage hydroelectric power generation device, thereby driving the first-stage hydroelectric power generation device to generate power at high pressure. The high-pressure medium is depressurized once and flows into the buffer tank for storage.

[0066] In the secondary energy release, the high-pressure medium in the buffer tank that has been depressurized once enters the secondary hydroelectric power generation device, thereby driving the secondary hydroelectric power generation device to generate power at low pressure. The high-pressure medium is depressurized for a second time, and after the pressure reaches atmospheric pressure, it flows into the working fluid storage unit for storage.

[0067] In some embodiments, the energy release process includes: compressed air pushes the high-pressure medium into the pressure regulating device, regulates the pressure of the high-pressure medium, and then sends it into the hydroelectric power generation device to generate work, so that the pressure of the high-pressure medium reaches atmospheric pressure and then flows into the working fluid storage unit for storage.

[0068] Example 1

[0069] This embodiment provides an underground energy storage device system using compressed air, including an air compression unit, a working fluid storage unit, an energy storage unit, and a power generation unit. Figure 1 As shown, the energy storage unit includes two first sealed pressure pipes 1 and four second sealed pressure pipes 2 which are arranged in parallel and buried underground.

[0070] like Figure 1 As shown, the air compression unit includes an air supply pipeline 3, an air pressurizing device 4 and two air supply branches 5 arranged side by side. The inlet end of the air pressurizing device 4 is connected to the air supply pipeline 3, and the outlet end of the air pressurizing device 4 is respectively connected to the two air supply branches. The two air supply branches 5 correspond to the two first sealed pressure pipes 1 one by one, and extend into the bottom of the inner cavity of the first sealed pressure pipe 1. The air pressurizing device 4 is used to compress the air and provide compressed air to the first sealed pressure pipe 1. A first regulating valve is independently provided on each air supply branch 5. The air supply branch 5 is also connected to the tops of the four second sealed pressure pipes 2 respectively through the air supply sub-branch 18, which is used to send compressed air into the second sealed pressure pipe 2. A third regulating valve is provided on the air supply sub-branch 18, which is used to connect the first sealed pressure pipe 1 with the second sealed pressure pipe 2.

[0071] Each second sealed pressure pipe 2 is also connected to the working medium storage unit and the power generation unit through a medium pipeline 6, and the medium pipeline 6 extends to the bottom of the inner cavity of the second sealed pressure pipe 2. A second regulating valve is provided on the medium pipeline 6 to connect the medium pipeline 6 and the power generation unit. An emptying component is also provided at the top of the second sealed pressure pipe 2 to exhaust the air in the second sealed pressure pipe 2.

[0072] The power generation unit includes a primary hydroelectric device 7, a buffer tank 8 and a secondary hydroelectric device 9 connected in sequence. The buffer tank 8 is buried underground, and the inlet and outlet ends of the primary hydroelectric device 7 are respectively provided with a feed pipeline 10 and a first discharge pipeline 11, the feed pipeline 10 is respectively connected to four medium pipelines 6, and the first discharge pipeline 11 is connected to the top of the buffer tank 8. The buffer tank 8 is connected to the inlet end of the secondary hydroelectric device 9 through the second discharge pipeline 12, and the end of the second discharge pipeline 12 away from the secondary hydroelectric device 9 extends to the bottom of the inner cavity of the buffer tank 8. The outlet end of the secondary hydroelectric device 9 is provided with a return pipeline 13 for connecting the working fluid storage unit.

[0073] The working medium storage unit includes a medium storage device 14 and a feed pipeline 15. The medium storage device 14 is connected to the return pipeline 13, one end of the feed pipeline 15 is connected to the medium storage device 14, and the other end is connected to four medium pipelines 6 respectively through a feed sub-branch 17, which is used to provide a transducing medium to the second sealed pressure pipe 2. A driving pump 16 is provided on the feed pipeline 15, and a fourth regulating valve is also provided on the feed sub-branch 17, which is used to connect the medium pipeline 6 and the medium storage device 14. The medium storage device 14 is also connected to the return pipeline 13, which is used to return the low-pressure medium discharged from the secondary hydropower generation device 9 to the medium storage device 14 for storage.

[0074] The energy storage process of the underground energy storage device system provided in this embodiment includes:

[0075] Connect the air compression unit and the energy storage unit, open the first regulating valve and the third regulating valve, and keep the other regulating valves closed, compress the air using the air compression unit, and send the compressed air into the first sealed pressure pipe 1 and the second sealed pressure pipe 2, so that the pressure of the first sealed pressure pipe 1 and the second sealed pressure pipe 2 reaches ≥10MPa, and then close the first regulating valve;

[0076] Connect the working fluid storage unit and the energy storage unit, open the fourth regulating valve, and use the working fluid storage unit to inject the transducing medium into the second sealed pressure tube 2 to press the compressed air in the second sealed pressure tube 2 into the first sealed pressure tube 1 until the second sealed pressure tube 2 is filled with the transducing medium and the pressure in the first sealed pressure tube 1 reaches 20-40MPa, thereby completing the energy storage.

[0077] The energy release process of the underground energy storage device system provided in this embodiment includes primary energy release and secondary energy release performed in sequence:

[0078] In the first-stage energy release, the energy storage unit and the power generation unit are connected, the second regulating valve and the third regulating valve are opened, and the other regulating valves are kept closed. The compressed air pushes the high-pressure medium into the first-stage hydroelectric power generation device, thereby driving the first-stage hydroelectric power generation device to generate power at high pressure. The high-pressure medium is depressurized once and flows into the buffer tank 8 for storage. In the second-stage energy release, the high-pressure medium in the buffer tank 8 that has been depressurized once enters the second-stage hydroelectric power generation device, thereby driving the second-stage hydroelectric power generation device to generate power at low pressure. The high-pressure medium is depressurized twice, and after the pressure reaches atmospheric pressure, it flows into the medium storage device 14 for storage.

[0079] Example 2

[0080] This embodiment provides an underground energy storage device system using compressed air, including an air compression unit, a working fluid storage unit, an energy storage unit, and a power generation unit. Figure 2 As shown, the energy storage unit includes two first sealed pressure pipes 1 and four second sealed pressure pipes 2 which are arranged in parallel and buried underground.

[0081] like Figure 2 As shown, the air compression unit includes an air supply pipeline 3, an air pressurizing device 4 and two air supply branches 5 arranged side by side. The inlet end of the air pressurizing device 4 is connected to the air supply pipeline 3, and the outlet end of the air pressurizing device 4 is respectively connected to the two air supply branches. The two air supply branches 5 correspond to the two first sealed pressure pipes 1 one by one, and extend into the bottom of the inner cavity of the first sealed pressure pipe 1. The air pressurizing device 4 is used to compress the air and provide compressed air to the first sealed pressure pipe 1. A first regulating valve is independently provided on each air supply branch 5. The air supply branch 5 is also connected to the tops of the four second sealed pressure pipes 2 respectively through the air supply sub-branch 18, which is used to send compressed air into the second sealed pressure pipe 2. A third regulating valve is provided on the air supply sub-branch 18, which is used to connect the first sealed pressure pipe 1 with the second sealed pressure pipe 2.

[0082] Each second sealed pressure pipe 2 is also connected to the working medium storage unit and the power generation unit through a medium pipeline 6, and the medium pipeline 6 extends to the bottom of the inner cavity of the second sealed pressure pipe 2. A second regulating valve is provided on the medium pipeline 6 to connect the medium pipeline 6 and the power generation unit. An emptying component is also provided at the top of the second sealed pressure pipe 2 to exhaust the air in the second sealed pressure pipe 2.

[0083] The power generation unit includes a pressure regulating device 19 and a hydroelectric power generation device 20 connected in sequence. The inlet end and the outlet end of the pressure regulating device 19 are respectively provided with a feed pipeline 10 and a discharge pipeline 21, the feed pipeline 10 is respectively connected to a plurality of the medium pipelines 6, and the discharge pipeline 21 is connected to the hydroelectric power generation device 20. The outlet end of the hydroelectric power generation device 20 is provided with a return pipeline 13, and the end of the return pipeline 13 away from the hydroelectric power generation device 20 is connected to the working medium storage unit.

[0084] The working medium storage unit includes a medium storage device 14 and a feed pipeline 15. The medium storage device 14 is connected to the return pipeline 13, one end of the feed pipeline 15 is connected to the medium storage device 14, and the other end is connected to four medium pipelines 6 respectively through a feed sub-branch 17, which is used to provide a transducing medium to the second sealed pressure pipe 2. A driving pump 16 is provided on the feed pipeline 15, and a fourth regulating valve is also provided on the feed sub-branch 17, which is used to connect the medium pipeline 6 and the medium storage device 14. The medium storage device 14 is also connected to the return pipeline 13, which is used to return the low-pressure medium discharged from the secondary hydropower generation device 9 to the medium storage device 14 for storage.

[0085] The energy storage process of the underground energy storage device system provided in this embodiment includes:

[0086] Connect the air compression unit and the energy storage unit, open the first regulating valve and the third regulating valve, and keep the other regulating valves closed, compress the air using the air compression unit, and send the compressed air into the first sealed pressure pipe 1 and the second sealed pressure pipe 2, so that the pressure of the first sealed pressure pipe 1 and the second sealed pressure pipe 2 reaches ≥10MPa, and then close the first regulating valve;

[0087] Connect the working fluid storage unit and the energy storage unit, open the fourth regulating valve, and use the working fluid storage unit to inject the transducing medium into the second sealed pressure tube 2 to press the compressed air in the second sealed pressure tube 2 into the first sealed pressure tube 1 until the second sealed pressure tube 2 is filled with the transducing medium and the pressure in the first sealed pressure tube 1 reaches 20-40MPa, thereby completing the energy storage.

[0088] The energy release process of the underground energy storage device system provided in this embodiment includes:

[0089] The compressed air pushes the high-pressure medium into the pressure regulating device 19 to adjust the pressure of the high-pressure medium, and then sends it to the hydroelectric power generation device 20 to generate power, so that the pressure of the high-pressure medium reaches atmospheric pressure and then flows into the working fluid storage unit for storage.

[0090] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. An underground energy storage device system using compressed air, characterized in that: The underground energy storage device system comprises an air compression unit, a working fluid storage unit, an energy storage unit and a power generation unit, wherein the energy storage unit is connected to the air compression unit, the working fluid storage unit and the power generation unit respectively; The energy storage unit is buried underground; The air compression unit is used to inject compressed air into the energy storage unit; The working fluid storage unit is used to provide a transducing medium to the energy storage unit, and the compressed air injected into the energy storage unit converts the transducing medium into a high-pressure medium for storage; The power generation unit is also connected to the working fluid storage unit. The high-pressure medium in the energy storage unit enters the power generation unit, is converted into a low-pressure medium, and flows into the working fluid storage unit.

2. The underground energy storage device system according to claim 1, characterized in that: The air compression unit includes an air supply pipeline, an air pressurizing device and a plurality of air supply branches; The air supply pipeline is connected to the inlet end of the air pressurizing device; A plurality of the air supply branches are arranged in parallel, one end of the air supply branch is connected to the outlet end of the air pressurizing device, and the other end is connected to the energy storage unit; At least one first regulating valve is arranged on the gas supply branch line.

3. The underground energy storage device system according to claim 2, characterized in that: The energy storage unit includes a plurality of first sealed pressure pipes and a plurality of second sealed pressure pipes buried underground; A plurality of first sealed pressure tubes are arranged in parallel, the gas supply branch extends into the bottom of the inner cavity of the first sealed pressure tube, and the gas supply branch is also connected to the tops of a plurality of second sealed pressure tubes through gas supply sub-branches; A plurality of second sealed pressure tubes are arranged in parallel, and the second sealed pressure tubes are respectively connected to the working fluid storage unit and the power generation unit through medium pipelines, and the medium pipelines extend into the bottom of the inner cavity of the second sealed pressure tubes; At least one second regulating valve is arranged on the medium pipeline; At least one third regulating valve is provided on the gas supply secondary branch; Preferably, an exhaust assembly is also provided on the top of the second sealed pressure tube, and the exhaust assembly is used to exhaust the air in the second sealed pressure tube.

4. The underground energy storage device system according to claim 3, characterized in that: The power generation unit comprises a primary hydroelectric power generation device, a buffer tank and a secondary hydroelectric power generation device connected in sequence; The buffer tank is buried underground; The inlet end and the outlet end of the first-level hydroelectric power generation device are respectively provided with a feed pipeline and a first discharge pipeline, the feed pipeline is respectively connected to a plurality of the medium pipelines, and the first discharge pipeline is connected to the top of the buffer tank; The buffer tank is connected to the inlet end of the secondary hydroelectric power generation device through a second discharge pipeline, and one end of the second discharge pipeline away from the secondary hydroelectric power generation device extends into the bottom of the inner cavity of the buffer tank; A return pipeline is provided at the outlet end of the secondary hydroelectric power generation device, and one end of the return pipeline away from the secondary hydroelectric power generation device is connected to the working medium storage unit.

5. The underground energy storage device system according to claim 3, characterized in that: The power generation unit includes a pressure regulating device and a hydroelectric power generation device; The inlet end and the outlet end of the pressure regulating device are respectively provided with a feed pipeline and a discharge pipeline, the feed pipeline is respectively connected to a plurality of the medium pipelines, and the discharge pipeline is connected to the hydroelectric power generation device; A return pipeline is provided at the outlet end of the hydroelectric power generation device, and one end of the return pipeline away from the hydroelectric power generation device is connected to the working medium storage unit.

6. The underground energy storage device system according to claim 4 or 5, characterized in that: The working fluid storage unit includes a medium storage device and a feed pipeline, the medium storage device is connected to the power generation unit, one end of the feed pipeline is connected to the medium storage device, and the other end is connected to the medium pipeline through a feed secondary branch; The feed pipeline is provided with a driving pump; At least one fourth regulating valve is arranged on the secondary feeding branch.

7. An underground energy storage method using compressed air, characterized in that: The underground energy storage method adopts the underground energy storage device system using compressed air as described in any one of claims 1 to 6, and the underground energy storage method includes an energy storage process and an energy release process; The energy storage process includes: connecting an air compression unit with an energy storage unit, compressing air with the air compression unit, and sending the compressed air into the energy storage unit until the air in the energy storage unit reaches a first preset pressure, closing the air compression unit, and connecting a working fluid storage unit with the energy storage unit, injecting a transducing medium into the energy storage unit with the working fluid storage unit, and the transducing medium compressing the air in the energy storage unit to reach a second preset pressure for energy storage; The energy release process includes: connecting the energy storage unit and the power generation unit so that the compressed air in the energy storage unit expands, the transducing medium is converted into a high-pressure medium and enters the power generation unit, the power generation unit performs work to generate electricity to release energy, and the high-pressure medium is converted into a low-pressure medium and flows to the working fluid storage unit.

8. The underground energy storage method according to claim 7, characterized in that: During the energy storage process, the compressed air provided by the air compression unit enters the first sealed pressure tube and the second sealed pressure tube respectively, so that the pressure of the first sealed pressure tube and the second sealed pressure tube reaches a first preset pressure; The energy conversion medium provided by the working fluid storage unit enters the second sealed pressure tube, and the compressed air in the second sealed pressure tube is pressed into the first sealed pressure tube until the second sealed pressure tube is filled with the energy conversion medium and the pressure in the first sealed pressure tube reaches the second preset pressure, thus completing energy storage; The first sealed pressure pipe and the second sealed pressure pipe independently exchange heat with the underground soil so that the compressed air maintains a constant temperature; Preferably, the transducing medium is water.

9. The underground energy storage method according to claim 7 or 8, characterized in that: The energy release process includes primary energy release and secondary energy release performed sequentially; In the first-stage energy release, the compressed air pushes the high-pressure medium into the first-stage hydroelectric power generation device, thereby driving the first-stage hydroelectric power generation device to generate power at high pressure, and the high-pressure medium is depressurized once and flows into the buffer tank for storage; In the secondary energy release, the high-pressure medium in the buffer tank that has been depressurized once enters the secondary hydroelectric power generation device, thereby driving the secondary hydroelectric power generation device to generate power at low pressure. The high-pressure medium is depressurized for a second time, and after the pressure reaches atmospheric pressure, it flows into the working fluid storage unit for storage.

10. The underground energy storage method according to claim 7 or 8, characterized in that: The energy release process includes: The compressed air pushes the high-pressure medium into the pressure regulating device, regulates the pressure of the high-pressure medium, and then sends it to the hydroelectric power generation device to generate work, so that the pressure of the high-pressure medium reaches atmospheric pressure and then flows into the working fluid storage unit for storage.

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