A compressed air power storage system

Abstract

The present invention discloses a compressed air electric energy storage system, including a constant pressure gas storage device, a high pressure liquid storage device, an energy storage component and an energy release component. In the energy storage state, the energy storage component converts electrical energy into air internal energy and stores it in the constant pressure gas storage unit in sequence. The pressure of the constant pressure gas storage device is adjusted to be constant and the liquid is recovered through the hydraulic pump and the hydraulic motor generator set; in the energy release state, the high pressure gas in the constant pressure gas storage unit drives the generator to generate electricity through the expansion unit, and at the same time, the high pressure liquid storage device injects liquid into the constant pressure gas storage unit to maintain its constant pressure, and uses the hydraulic pump set to recover the liquid in the gas storage unit that has completed the energy release. The present invention realizes constant pressure energy storage and energy release of the compressed air electric energy storage system through the recycling of high pressure liquid, which can effectively reduce the cost of large-scale electric energy storage capacity and improve the economy of the compressed air electric energy storage system.

Description

Technical Field

[0001] The invention relates to the technical field of power conversion and storage, in particular to a compressed air power energy storage system. Background Art

[0002] In the context of traditional fossil energy facing increasingly prominent problems such as rising costs, resource depletion and environmental pollution, clean renewable energy such as wind power and photovoltaic power generation has developed rapidly in recent years and will gradually replace traditional fossil energy to become one of the main energy supplies in the future. As the proportion of random and intermittent renewable power sources in the power grid gradually increases, the uncertainty of power supply and consumption increases due to the limitation of the power system's own regulation ability. In order to give priority to the safe and stable operation of the power grid, a large amount of wind power and photovoltaic power are abandoned and cannot be connected to the Internet every year, and a large number of wind turbines are idle. Power storage technology can move fluctuating and intermittent energy in the time dimension, which is an effective means to solve the quality problem of fluctuating renewable power grid connection and improve the utilization rate of renewable energy.

[0003] Pumped storage and compressed air energy storage are currently the two most economical and feasible technologies for large-scale power energy storage. Among them, pumped storage technology is mature and widely used, but the construction of pumped storage power stations is constrained by geographical conditions and will have a significant impact on the surrounding ecological environment. Compressed air energy storage technology is developed based on gas turbine power generation technology. When electricity consumption is low, electricity is stored in the form of high-pressure air internal energy. When electricity consumption is peak, high-pressure air drives the gas turbine to generate electricity. The gas storage device of the compressed air energy storage power station can be a large-capacity underground cave, mine, etc., or it can be a flexibly arranged steel pressure vessel or pipeline. Compared with pumped storage power stations, it has the advantages of high energy storage density, short construction period, and no geographical restrictions, and the unit investment cost is equivalent to or even lower than that of pumped storage.

[0004] The existing compressed air energy storage technology has the following shortcomings:

[0005] (1) The gas storage pressure of the simple and low-cost constant volume gas storage device is constantly changing during the energy storage and release process. On the one hand, it causes the compressor unit and the expansion unit to be unable to operate under the efficient and stable design conditions, which affects the energy conversion efficiency of the energy storage system; on the other hand, it leads to low energy storage density, high energy storage capacity cost, and poor economic efficiency of the energy storage system.

[0006] (2) Existing constant pressure gas storage devices, such as “A two-stage energy storage system based on constant pressure gas storage” (patent application number: 201710096017.5) and “Compressed air power energy storage system” (patent authorization announcement number: CN 104121049 B), respectively disclose a constant pressure gas storage solution based on air pressure-hydraulic coupling, but require the configuration of high-pressure liquid storage capacity of the same scale as the gas storage capacity, which increases the energy storage capacity cost; “A water-sealed double-layer constant pressure gas storage system” (patent application number: 201610942999.0) discloses a constant pressure gas storage system composed of a gas storage tank with a special structure. The principle of its constant pressure gas storage is also air pressure-hydraulic coupling, but it can use the liquid drive device to output work when storing gas at constant pressure, while the liquid drive device needs to consume energy when discharging gas at constant pressure, which is opposite to the energy flow direction of the compressed air energy storage system, resulting in a decrease in the system energy storage density and energy conversion utilization rate. Summary of the invention

[0007] In order to overcome the above-mentioned deficiencies of the prior art, the present invention provides a compressed air electric energy storage system, which is based on constant-pressure gas storage in parallel with multiple gas storage units, and realizes energy recovery and recycling through conversion and circulation between air energy and electric energy.

[0008] The technical solution adopted by the present invention to solve the above technical problems is: a compressed air power energy storage system, comprising:

[0009] The constant pressure gas storage device comprises a constant pressure container in which a liquid is pre-stored;

[0010] A high-pressure liquid storage device, comprising a high-pressure container, the high-pressure container being connected to a normal-pressure container in the constant-pressure gas storage device;

[0011] The energy storage component includes an electric motor and an air compressor unit. The air compressor unit is driven by the electric motor, and the exhaust port of the air compressor unit is connected to the mouth of the constant pressure container. In the energy storage state, the electric motor drives the air compressor unit to compress the normal pressure air and transport it to the constant pressure container. The constant pressure container discharges the pre-stored liquid into the high pressure container to maintain its own constant pressure. When the pressure in the constant pressure container decreases, the high pressure container refills the liquid into it.

[0012] The energy release component includes a generator and an expansion unit. The expansion unit drives the generator to work, and the air inlet of the expansion unit is connected to the mouth of the constant pressure container. In the energy release state, the constant pressure container releases the high-pressure air therein to the expansion unit, and the expansion work of the expansion unit drives the generator to generate electricity. At the same time, the high-pressure container fills the constant pressure container with liquid to maintain its constant pressure. The constant pressure container that completes energy release injects the remaining liquid into the high-pressure container.

[0013] Furthermore, the constant pressure gas storage device includes at least one constant pressure container. When there are multiple constant pressure containers, these constant pressure containers are connected in parallel between the energy storage component and the energy release component.

[0014] Furthermore, the electric energy storage system includes a first pipeline connecting an air compressor, multiple constant pressure containers and an expansion unit, a first valve is arranged at the exhaust port of the air compressor, a second valve is arranged at the air inlet of the expansion unit, and multiple constant pressure containers are connected in parallel to the first pipeline through respective matching third valves.

[0015] Furthermore, a second pipeline for releasing liquid and a third pipeline for refilling liquid are provided between the constant pressure container and the high pressure container, a hydraulic pump and a fourth valve are provided on the second pipeline, and a hydraulic motor generator set and a fifth valve are provided on the third pipeline.

[0016] Furthermore, outlets of the plurality of constant pressure containers are respectively connected to the second pipeline and the third pipeline.

[0017] Furthermore, three-way valves are provided at the outlets of the multiple constant pressure containers, the liquid outlet end of the three-way valve is connected in parallel to the second pipeline, and the liquid inlet end of the three-way valve is connected in parallel to the third pipeline;

[0018] In the energy storage state, the liquid outlet end of the three-way valve at the outlet of the constant pressure container in the inflated state is opened, and the liquid therein is discharged into the high-pressure container through the second pipeline and the hydraulic pump. At the same time, the liquid inlet end of the three-way valve of the constant pressure container to be inflated is opened, and the liquid in the high-pressure container is filled into it through the hydraulic motor generator set and the third pipeline; in the energy release state, the liquid inlet end of the three-way valve at the outlet of the constant pressure container in the energy release state is opened, and the liquid in the high-pressure container is filled into it through the hydraulic motor generator set and the third pipeline. At the same time, the liquid outlet end of the three-way valve at the outlet of the constant pressure container that has completed energy release is opened, and the liquid therein is discharged into the high-pressure container through the second pipeline and the hydraulic pump.

[0019] Furthermore, a first outlet and a second outlet are respectively provided on the plurality of constant pressure containers, the first outlet is connected to the second pipeline via a liquid outlet valve, and the second outlet is connected to the third pipeline via a liquid inlet valve;

[0020] In the energy storage state, the liquid outlet valve of the constant pressure container in the inflated state is opened, and the liquid therein is discharged into the high-pressure container through the hydraulic pump and the second pipeline. At the same time, the liquid inlet valves of the constant pressure container to be inflated are opened in sequence from upstream to downstream, and the liquid in the high-pressure container is filled into it through the hydraulic motor generator set and the third pipeline; in the energy release state, the liquid inlet valve of the constant pressure container in the energy release state is opened, and the liquid in the high-pressure container is filled into it through the hydraulic motor generator set and the third pipeline. At the same time, the liquid outlet valves of the constant pressure container that has completed energy release are opened in sequence from downstream to upstream, and the liquid therein is discharged into the high-pressure container through the hydraulic pump and the second pipeline.

[0021] Furthermore, in the energy storage state, the liquid flow rate discharged from the constant pressure container in the gas-filled state to the high-pressure container is determined by the flow rate of the gas compressed into the constant pressure gas storage device by the air compressor unit; the liquid filling flow rate from the high-pressure container to the constant pressure container to be filled should be equal to the liquid flow rate discharged from the constant pressure container in the gas-filled state to the high-pressure container;

[0022] In the energy release state, the liquid filling flow rate from the high-pressure container to the constant-pressure container in the energy release state is determined by the gas flow rate of the constant-pressure gas storage device entering the expansion unit to expand and do work; the liquid flow rate discharged from the constant-pressure container that has completed energy release to the high-pressure container should be equal to the liquid flow rate of the high-pressure container to the constant-pressure container in the energy release state.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) Multiple independent constant pressure containers (gas storage units) are connected in parallel as a constant pressure gas storage device. The liquid volume in each gas storage unit is controlled to maintain a constant pressure during the energy storage and release process. This allows the compressor unit and the expansion unit of the compressed air power energy storage system to always operate under rated pressure conditions during the energy storage and release process. This overcomes the problems of low system energy conversion efficiency and unstable operation caused by the continuous change of gas storage pressure during the energy storage and release process of traditional constant volume gas storage devices, thereby improving the energy storage efficiency. On the other hand, the realization of constant volume gas storage greatly improves the energy storage density, thereby improving the economy of the energy storage system.

[0025] (2) By establishing a circulation loop of a hydraulic pump and a hydraulic motor generator set between a high-pressure liquid storage device and a constant-pressure gas storage device composed of multiple independent gas storage units in parallel, a small-capacity high-pressure liquid storage device can be used to achieve large-capacity constant-pressure gas storage, thereby greatly reducing the energy storage cost of ground gas storage devices that can be flexibly arranged based on steel pressure vessels, pipelines, etc.; on the other hand, during the liquid circulation process, the power generation of the synchronously running hydraulic motor generator set can basically offset the power consumption of the hydraulic pump, thereby improving the overall energy conversion utilization rate of the system.

[0026] The present invention realizes constant-pressure energy storage and release of the compressed air power energy storage system through the recycling of high-pressure liquid, which can effectively reduce the cost of large-scale power storage capacity, improve the economy of the compressed air power energy storage system, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the structure of Example 1.

[0028] Figure 2 This is a schematic diagram of the structure of Example 2.

[0029] Description of the main components of the present invention:

[0030] 1-electric motor; 2-air compressor unit; 3-exhaust port of air compressor unit, 4-first valve, 5-first pipeline, 6-third valve, 7-constant pressure gas storage device, 7-a, 7-b, 7-c, 7-d, ..., 7-n-multiple constant pressure containers, 8-second valve, 9-air inlet of expansion unit, 10-expansion unit, 11-generator, 12-three-way valve, 13-second pipeline, 14-third pipeline, 15-hydraulic motor generator set, 16-fifth valve, 17-hydraulic pump, 18-fourth valve, 19-high pressure container, 20-liquid inlet valve, 21-liquid outlet valve. DETAILED DESCRIPTION

[0031] The present invention will be further described below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be noted that similar or identical parts in the accompanying drawings are annotated with the same figure number; implementation methods not described are well known in the relevant technical field.

[0032] The present invention provides a compressed air power energy storage system based on constant pressure gas storage in multiple gas storage units. The compressed air power energy storage system modularly decomposes the gas storage device into a plurality of independent gas storage units in parallel, and uses a high-pressure liquid storage device and each gas storage unit to form a plurality of liquid circulation loops, so as to control the liquid volume in each gas storage unit to maintain a constant pressure in each gas storage unit during the energy storage and energy release process, so that the compressor unit and the expansion unit of the compressed air power energy storage system always operate under the rated pressure conditions during the energy storage and energy release process, thereby solving the problem of gas storage pressure change of the traditional constant volume gas storage device during the energy storage and energy release process, and the problem that the existing constant pressure gas storage device is not flexible enough and the cost is too high.

[0033] Two embodiments of the present invention are provided in this section. Those skilled in the art should be aware that the embodiments are merely descriptions of one or several implementations of the present invention, and their purpose is to describe the contents of the present invention more clearly and specifically, and are not intended to limit the protection scope of the present invention.

[0034] Example 1, refer to the attached Figure 1 .

[0035] Example 1 provides a compressed air power energy storage system based on constant pressure gas storage in multiple gas storage units.

[0036] like Figure 1 As shown, the compressed air power storage system of this embodiment includes: a motor 1, an air compressor unit 2, a constant pressure gas storage device 7, a three-way valve assembly 12, a high pressure liquid storage device 19, an expansion unit 10 and a generator unit 11. Among them, the driving power supply of the motor 1 includes but is not limited to one or more combinations of grid power, nuclear power, wind power, solar power generation, etc.

[0037] The air compressor unit 2 is driven directly or indirectly by the electric motor 1, and its air inlet is connected to the ambient air. The exhaust port 3 is connected to the first pipeline 5 through the first valve 4. The first pipeline 5 is connected in parallel with multiple constant pressure containers 7-a, 7-b, 7-c, 7-d,..., 7-n in the constant pressure gas storage device 7, and each constant pressure container is connected to the first pipeline 5 through the third valve 6.

[0038] In this embodiment, the air compressor unit is a multi-stage compressor unit composed of two or more air compressors. A cooling heat exchanger is arranged between adjacent air compressors and after the last-stage air compressor in the multi-stage air compressor unit to cool the outlet air of each stage of the air compressor, thereby achieving approximately isothermal compression to reduce the unit power consumption of the compressor unit, and at the same time, the compression heat can be recovered and utilized.

[0039] The other end of the first pipeline 5 is connected to the air inlet 9 of the expansion unit 10 through the second valve 8. When the first valve 4 is closed and the second valve 8 is opened, the expansion unit 10 is connected to the constant pressure gas storage device 7 through the first pipeline 5. When the first valve 4 is opened and the second valve 8 is closed, the air compressor unit 2 is connected to the constant pressure gas storage device 7 through the first pipeline 5.

[0040] In this embodiment, the expansion unit is a multi-stage expansion unit composed of two or more expansion units, and a heating heat exchanger is arranged between adjacent expansion units and before the first-stage expansion unit in the multi-stage expansion unit to heat the compressed air, thereby achieving approximately isothermal expansion and increasing the output work per unit of compressed air. The heat source of the heating heat exchanger can be one or more combinations of compression heat recovered in the energy storage stage, electric heating, and heating by renewable energy such as solar energy.

[0041] The outlet of each constant pressure container in the constant pressure gas storage device 7 is connected to the liquid inlet and outlet of the high-pressure container 19 respectively through the three-way valve 12, wherein the liquid outlet of the three-way valve 12 is connected to the liquid inlet of the high-pressure container 19 through the second pipeline 13, a hydraulic pump 17 is arranged on the second pipeline 13, and a fourth valve 18 is arranged at the liquid inlet of the high-pressure container 19. The liquid inlet of the three-way valve 12 is connected to the liquid outlet of the high-pressure container 19 through the third pipeline 14, a hydraulic motor generator set 15 is arranged on the third pipeline 14, and a fifth valve 16 is arranged at the liquid outlet of the high-pressure container 19. In this way, the second pipeline 13, the third pipeline 14 and the high-pressure container 19 are connected to form a liquid circulation loop, and the pressure of each constant pressure container is controlled to keep it working at a constant pressure.

[0042] In this embodiment, the energy storage state and energy release state of the compressed air power energy storage system based on constant pressure gas storage in multiple gas storage units are as follows:

[0043] In the energy storage state, the first valve 4 is opened, and the third valve 6 and the liquid outlet end of the three-way valve 12 and the fourth valve 18 corresponding to each constant pressure container in the constant pressure gas storage device 7 are opened in sequence from upstream to downstream (i.e., from the air compressor unit end to the expansion unit end), and the second valve 8 is closed, and the motor 1 drives the air compressor unit 2 to work; the normal temperature and pressure air enters the air compressor unit 2, undergoes multi-stage compression and inter-stage cooling, and then enters the constant pressure containers corresponding to the constant pressure gas storage device 7 in sequence through the outlet 3 of the air compressor unit 2, the first valve 4, the first pipeline 5 and the third valve 6 for storage; at the same time, the liquid in the constant pressure container in the constant pressure storage device 7 in the inflated state is pumped through the liquid outlet end of the three-way valve 12, the second pipeline 13 and the fourth valve 1 through the hydraulic pump 17. 8 is injected into the high-pressure container 19 to keep the pressure of each constant-pressure container in the constant-pressure gas storage device 7 constant; thereafter, the fifth valve 16 is opened, and the liquid inlet ends of the three-way valves 12 corresponding to the constant-pressure containers to be filled in the constant-pressure gas storage device 7 are opened in sequence from downstream to upstream (i.e., from the expansion unit end to the air compressor unit end), and the liquid in the high-pressure container 19 passes through the fifth valve 16 to generate electricity through the hydraulic motor generator set 15, and then is injected into the constant-pressure containers to be filled in the constant-pressure gas storage device 7 through the third pipeline 14 and the liquid inlet end of the three-way valve 12, so as to realize the recycling of the liquid in the energy storage process; when the energy storage is finished, the first valve 4, the fifth valve 16, the fourth valve 18 and the third valve 6 and the three-way valve 12 corresponding to each constant-pressure container in the constant-pressure gas storage device 7 are closed.

[0044] In the energy release state, the second valve 8 is opened, and the third valve 6, the liquid inlet end of the three-way valve 12 and the fifth valve 16 corresponding to each constant pressure container in the constant pressure gas storage device 7 are opened in sequence from downstream to upstream, and the first valve 4 is closed; the high-pressure air in each constant pressure container in the constant pressure gas storage device 7 enters the expansion unit 10 through the third valve 6, the first pipeline 5, the second valve 8 and the air inlet 9 of the expansion unit for inter-stage heating and multi-stage expansion to perform work, thereby driving the generator 11 to generate electricity; at the same time, the liquid in the high-pressure container 19 drives the hydraulic motor generator set 15 to generate electricity through the fifth valve 16, and then is injected into the constant pressure storage through the third pipeline 14 and the liquid inlet end of the three-way valve 12 of the constant pressure container in the energy release state. The corresponding constant pressure container in the constant pressure gas storage device 7 is opened to keep the pressure of each constant pressure container in the constant pressure gas storage device 7 constant; then, the fourth valve 18 is opened, and the liquid outlet ends of the three-way valves 12 corresponding to the constant pressure containers in the constant pressure gas storage device 7 that have completed energy release are opened in sequence from upstream to downstream, and the liquid in the constant pressure container in the constant pressure gas storage device 7 that has completed energy release is injected into the high-pressure container 19 through the liquid outlet end of the three-way valve 12, the second pipeline 13 and the fourth valve 18 through the hydraulic pump 17 to realize the recycling of the liquid in the energy storage process; after the energy release is completed, the second valve 8, the fifth valve 16, the fourth valve 18 and the third valve 6 and the three-way valve 12 corresponding to each constant pressure container in the constant pressure gas storage device 7 are closed.

[0045] In general, the energy storage state and energy release state of the compressed air power energy storage system of the present invention do not exist at the same time. In the energy storage state, the flow of the hydraulic pump 17 and the hydraulic motor generator set 15 is controlled by the flow of the air compressor set 2 to keep the inflation pressure of the constant pressure gas storage device 7 constant and the pressure of the high pressure container 19 stable; in the energy release state, the flow of the hydraulic pump 17 and the hydraulic motor generator set 15 is controlled by the flow of the expansion unit 10 to keep the energy release pressure of the constant pressure gas storage device 7 constant and the pressure of the high pressure container 19 stable.

[0046] Example 2, refer to the attached Figure 2 .

[0047] Example 2 provides another type of compressed air power energy storage system based on constant pressure gas storage in multiple gas storage units.

[0048] The structural composition of this embodiment is similar to that of the first embodiment, and the only difference lies in the connection relationship between the constant pressure containers in the constant pressure gas storage device 7 and the high pressure container 19.

[0049] like Figure 2As shown, each constant pressure container in the constant pressure gas storage device 7 is connected to the first pipeline 13 through the corresponding liquid outlet valve 20, and is connected to the second pipeline 14 through the corresponding liquid inlet valve 21, thereby forming a liquid circulation loop with the high-pressure container 19, and the pressure of each constant pressure container is controlled to maintain constant pressure operation. That is to say, in this embodiment, the three-way valve 12 is replaced by the liquid outlet valve 20 and the liquid inlet valve 21, and the other implementation methods are the same as those in Example 1.

[0050] In this embodiment, the energy storage state and energy release state of the compressed air power energy storage system based on constant pressure gas storage in multiple gas storage units are as follows:

[0051] In the energy storage state, the first valve 4 is opened, and the third valve 6, the liquid outlet valve 20 and the fourth valve 18 corresponding to each constant pressure container in the constant pressure gas storage device 7 are opened in sequence from upstream to downstream, and the second valve 8 is closed; the motor 1 drives the air compressor unit 2 to work; the air at normal temperature and pressure enters the air compressor unit 2, undergoes multi-stage compression and inter-stage cooling, and then enters the constant pressure container corresponding to the constant pressure gas storage device 7 through the outlet 3 of the air compressor unit 2, the first valve 4, the first pipeline 5 and the third valve 6 in sequence for storage; at the same time, the liquid in the constant pressure container in the constant pressure storage device 7 in the inflated state is injected into the high pressure gas storage device 7 through the liquid outlet valve 20, the second pipeline 13 and the fourth valve 18 through the hydraulic pump 17. The high-pressure container 19 is opened to keep the pressure of the constant-pressure container in the constant-pressure gas storage device 7 constant; then, the fifth valve 16 is opened, and the liquid inlet valves 21 corresponding to the constant-pressure containers to be filled in the constant-pressure gas storage device 7 are opened in sequence from downstream to upstream, and the liquid in the high-pressure container 19 is generated through the fifth valve 16 by the hydraulic motor generator set 15, and then injected into the constant-pressure container to be filled in the constant-pressure gas storage device 7 through the third pipeline 14 and the liquid inlet valve 21, so as to realize the recycling of the liquid in the energy storage process; when the energy storage is finished, the first valve 4, the fifth valve 16, the fourth valve 18 and the third valve 6, the liquid outlet valve 20 and the liquid inlet valve 21 corresponding to each constant-pressure container in the constant-pressure gas storage device 7 are closed.

[0052] In the energy release state, the second valve 8 is opened, and the third valve 6, the liquid inlet valve 21 and the fifth valve 16 corresponding to each constant pressure container in the constant pressure gas storage device 7 are opened in sequence from downstream to upstream, and the first valve 4 is closed; the high-pressure air in each constant pressure container in the constant pressure gas storage device 7 enters the expansion unit 10 through the third valve 6, the first pipeline 5, the second valve 8 and the air inlet 9 of the expansion unit for inter-stage heating and multi-stage expansion to perform work, thereby driving the generator 11 to generate electricity; at the same time, the liquid in the high-pressure container 19 drives the hydraulic motor generator set 15 to generate electricity through the fifth valve 16, and then is injected into the constant pressure gas storage device 7 through the third pipeline 14 and the liquid inlet valve 21 of the constant pressure container in the energy release state. The first pipeline 13 and the fourth valve 18 are connected to the corresponding constant pressure container in the constant pressure gas storage device 7 to keep the pressure of each constant pressure container in the constant pressure gas storage device 7 constant; then, the fourth valve 18 is opened, and the liquid outlet valves 20 corresponding to the constant pressure containers in the constant pressure gas storage device 7 that have completed energy release are opened in sequence from upstream to downstream, and the liquid in the constant pressure containers in the constant pressure gas storage device 7 that have completed energy release is injected into the high-pressure container 19 through the liquid outlet valve 20, the first pipeline 13 and the fourth valve 18 through the hydraulic pump 17 to realize the recycling of the liquid in the energy storage process; after the energy release is completed, the second valve 8, the fifth valve 16, the fourth valve 18 and the third valve 6, the liquid outlet valve 20 and the liquid inlet valve 21 corresponding to each constant pressure container in the constant pressure gas storage device 7 are closed.

[0053] So far, the two embodiments of the present invention based on the compressed air power energy storage system with constant pressure gas storage in multiple gas storage units have been described in detail with reference to the accompanying drawings.

[0054] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for operating a compressed air power storage system, characterized in that: include: The constant pressure gas storage device is composed of a constant pressure container in which liquid is pre-stored; A high-pressure liquid storage device, comprising a high-pressure container, the high-pressure container being connected to a constant-pressure container in the constant-pressure gas storage device; The energy storage assembly includes an electric motor and an air compressor unit, wherein the air compressor unit is driven by the electric motor, and an exhaust port of the air compressor unit is connected to the mouth of the constant pressure container; In the energy storage state, the motor drives the air compressor unit to compress the normal pressure air and deliver it to the constant pressure container. The constant pressure container discharges the pre-stored liquid into the high pressure container to maintain its own constant pressure. When the pressure in the constant pressure container decreases, the high pressure container refills the liquid into it. The energy release component includes a generator and an expansion unit. The expansion unit drives the generator to work. The air inlet of the expansion unit is connected to the mouth of the constant pressure container. In the energy release state, the constant pressure container releases the air therein to the expansion unit, and the expansion unit expands and works to drive the generator to generate electricity. At the same time, the high-pressure container fills the constant pressure container with liquid to maintain its constant pressure. The constant pressure container that has completed energy release injects the remaining liquid into the high-pressure container. In the energy storage state, the liquid flow rate discharged from the constant pressure container in the inflated state to the high pressure container is determined by the flow rate of gas compressed into the constant pressure gas storage device by the air compressor unit; the liquid filling flow rate from the high pressure container to the constant pressure container to be inflated should be equal to the liquid flow rate discharged from the constant pressure container in the inflated state into the high pressure container; in the energy release state, the liquid filling flow rate from the high pressure container to the constant pressure container in the energy release state is determined by the gas flow rate of the constant pressure gas storage device entering the expansion unit to expand and do work; the liquid flow rate discharged from the constant pressure container that has completed energy release to the high pressure container should be equal to the liquid flow rate of the high pressure container to the constant pressure container in the energy release state; The constant pressure gas storage device includes at least one constant pressure container. When there are multiple constant pressure containers, these constant pressure containers are connected in parallel between the energy storage component and the energy release component. The electric energy storage system comprises a first pipeline connecting an air compressor, a plurality of constant pressure containers and an expansion unit, a first valve is arranged at the exhaust port of the air compressor, a second valve is arranged at the air inlet of the expansion unit, and a plurality of constant pressure containers are connected in parallel to the first pipeline through respective matching third valves; A second pipeline for releasing liquid and a third pipeline for refilling liquid are provided between the constant pressure container and the high pressure container, a hydraulic pump and a fourth valve are provided on the second pipeline, and a hydraulic motor generator set and a fifth valve are provided on the third pipeline; The outlets of the multiple constant pressure containers are respectively connected to the second pipeline and the third pipeline; A three-way valve is provided at the outlet of the plurality of constant pressure containers, the liquid outlet end of the three-way valve is connected in parallel to the second pipeline, and the liquid inlet end of the three-way valve is connected in parallel to the third pipeline; In the energy storage state, the liquid outlet end of the three-way valve at the outlet of the constant pressure container in the inflated state is opened, and the liquid therein is discharged into the high-pressure container through the second pipeline and the hydraulic pump. At the same time, the liquid inlet end of the three-way valve of the constant pressure container to be inflated is opened, and the liquid in the high-pressure container is filled therein through the hydraulic motor generator set and the third pipeline; in the energy release state, the liquid inlet end of the three-way valve at the outlet of the constant pressure container in the energy release state is opened, and the liquid in the high-pressure container is filled therein through the hydraulic motor generator set and the third pipeline. At the same time, the liquid outlet end of the three-way valve at the outlet of the constant pressure container that has completed energy release is opened, and the liquid therein is discharged into the high-pressure container through the second pipeline and the hydraulic pump; A first outlet and a second outlet are respectively provided on the plurality of constant pressure containers, the first outlet is connected to the second pipeline via a liquid outlet valve, and the second outlet is connected to the third pipeline via a liquid inlet valve; In the energy storage state, the liquid outlet valve of the constant pressure container in the inflated state is opened, and the liquid therein is discharged into the high-pressure container through the hydraulic pump and the second pipeline. At the same time, the liquid inlet valves of the constant pressure container to be inflated are opened in sequence from upstream to downstream, and the liquid in the high-pressure container is filled into it through the hydraulic motor generator set and the third pipeline; in the energy release state, the liquid inlet valve of the constant pressure container in the energy release state is opened, and the liquid in the high-pressure container is filled into it through the hydraulic motor generator set and the third pipeline. At the same time, the liquid outlet valves of the constant pressure container that has completed energy release are opened in sequence from downstream to upstream, and the liquid therein is discharged into the high-pressure container through the hydraulic pump and the second pipeline.

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