CN114718686B - Low-pressure-difference sealed gravity compressed air energy storage system and method - Google Patents

Abstract

The application provides a low-pressure-difference sealed gravity compressed air energy storage system and a method, wherein the energy storage system comprises a vertical shaft and a sealing film, a gravity plunger is movably inserted into the vertical shaft, and a gap is reserved between the vertical shaft and the gravity plunger; the seal membrane is located in the clearance, the seal membrane with the shaft with sealing connection between the gravity plunger makes the gravity plunger the seal membrane with the shaft is located enclose into the gas storage chamber between the space of seal membrane below for save compressed air, the seal membrane the gravity plunger with the shaft is located enclose between the space of seal membrane top and become the regulation chamber, it has pressure fluid to let in the regulation chamber, pressure fluid is right the inside and outside pressure differential of seal membrane can be reduced to the pressure effect of pressure fluid to the seal membrane through injecting pressure fluid in the regulation chamber of seal membrane top, thereby reduces the seal membrane stress, improves the seal membrane life-span, reduces the seal membrane cost.

Description

A low differential pressure sealed gravity compressed air energy storage system and method

technical field

The present application relates to the technical field of electrical energy storage, and in particular, to a low differential pressure sealed gravity compressed air energy storage system and method.

Background technique

The core of the air storage chamber for gravity compressed air energy storage is the air storage chamber sealing membrane. In the existing project plan, one side of the cylindrical sealing membrane is connected to the shaft wall, and the other side is anchored on the weight to form an arched sealing structure. At this time, the outside of the sealing film is normal atmospheric pressure, and the inside is high-pressure gas, so the sealing film is subjected to high-strength tensile stress, which reduces the service life of the sealing film.

SUMMARY OF THE INVENTION

The present application aims to solve one of the technical problems in the related art at least to a certain extent.

Therefore, the purpose of this application is to propose a low differential pressure sealed gravity compressed air energy storage system. By injecting pressure liquid into the adjustment cavity above the sealing film, the pressure effect of the pressure liquid on the sealing film can reduce the pressure difference between the inside and outside of the sealing film. , thereby reducing the stress of the sealing film, improving the life of the sealing film, and reducing the cost of the sealing film.

In order to achieve the above purpose, a low-pressure differential sealed gravity compressed air energy storage system proposed in this application includes:

a vertical shaft, a gravity plunger is movably inserted in the vertical shaft, and there is a gap between the vertical shaft and the gravity plunger;

a sealing membrane, the sealing membrane being located in the gap, the sealing membrane being in a sealed connection with the shaft and the gravity plunger, so that the gravity plunger, the sealing membrane and the shaft are located in the The space below the sealing film is surrounded by an air storage chamber, the air storage chamber is used for storing compressed air, and the space above the sealing film is surrounded by the sealing film, the gravity plunger and the shaft above the sealing film an adjustment cavity, into which a pressure liquid is passed, and the pressure liquid exerts a downward pressure on the sealing membrane.

Further, a pressure liquid storage device is also included, and the pressure liquid storage device is connected to the adjustment chamber, so that when the pressure of the compressed air in the air storage chamber increases, the pressure liquid storage device passes through the pressure liquid storage device to the adjustment chamber. The pressure fluid was introduced to reduce the pressure difference of the sealing membrane.

Further, the sealing film is a cylindrical structure, the sealing film includes a plurality of supporting ribs, the plurality of supporting ribs are surrounded on the peripheral side of the cylindrical structure, and an elastic seal is used between two adjacent supporting ribs. The membrane is connected to form a tubular structure by a plurality of the support ribs and the elastic sealing membrane;

The top end of the sealing film is bent inward to form an inner ring and an outer ring, the inner ring is connected with the top end of the outer ring, the bottom end of the inner ring is sealed and connected to the outer wall of the gravity plunger, and the The bottom end of the outer ring is connected to the inner wall of the shaft.

Further, the outer diameter of the outer ring is the same as the inner diameter of the shaft, so that the support ribs and the elastic sealing film of the outer ring are connected to the inner wall of the shaft;

The support ribs of the inner ring are connected with the outer wall of the gravity plunger.

Further, the top of the gravity plunger is provided with a locking assembly, so that the gravity plunger moving downward is supported on the ground at the top of the shaft through the locking assembly, so that the gravity plunger is at the bottom There is a certain space in the air storage cavity when the limit is located;

The top of the gravity plunger is provided with an above-ground gravity component, and the above-ground gravity component is located outside the shaft.

Further, the above-ground gravity assembly includes a support table and a plurality of gravity block groups arranged on the support table, the support table is fixed on the top of the gravity plunger, and a plurality of the gravity block groups are equiangularly distributed on the the peripheral side of the gravity plunger, so as to apply a downward force to the gravity plunger through the support table and the plurality of gravity block groups.

Further, it also includes a plurality of first guide rails, and the plurality of first guide rails are distributed on the peripheral side of the support table;

The peripheral side of the support table is provided with a first guide component matched with the first guide rail, so as to limit the position of the support table and the gravity plunger through the first guide rail.

Further, the gravity block group includes a plurality of superimposed above-ground gravity blocks;

A plurality of second guide rails are arranged on the support table on the peripheral side of the gravity block group, and a plurality of the above-ground gravity blocks are connected. The second guide assembly is matched with the second guide rail to limit the position of the plurality of the ground gravity blocks on each of the gravity block groups through the second guide rail.

Further, the gravity plunger includes a pressure-bearing cylinder and a plurality of superimposed filling gravity blocks filled in the pressure-bearing cylinder;

the locking assembly is arranged on the top end of the pressure-bearing cylinder;

The inner wall of the pressure-bearing cylinder is provided with a plurality of positioning guide grooves along the axial direction, and the outer wall of the filling weight block is provided with a positioning block matched with the positioning guide groove, so as to pass the limit of the positioning guide groove. The position action makes the center of gravity of the plurality of filling gravity blocks on the axis of the pressure-bearing cylinder.

A low-pressure differential sealed gravity compressed air energy storage method, comprising the following methods:

The sealing film is sealed between the gravity plunger and the shaft, so that the space between the gravity plunger, the sealing film and the shaft under the sealing film encloses an air storage cavity, and the sealing film, the gravity plunger and the shaft are located in the sealing film An adjustment cavity is formed between the space above;

When storing energy, the electric motor drives the air compressor unit to do work, and the compressed air obtained from the work is passed into the air storage cavity, the air pressure in the air storage cavity gradually increases, and pressure liquid is introduced into the adjustment cavity, and the air storage cavity When the pressure increases, the amount of pressure liquid introduced also increases, maintaining the internal and external pressure difference of the sealing membrane. When the pressure in the air storage chamber increases to the target pressure, push the gravity plunger to move up to the highest limit and stop;

When the energy is released, the high-pressure air in the air storage chamber does work to the air expansion unit, which drives the motor to generate electricity, the gravity plunger moves downward, the air storage volume in the air storage chamber decreases, the gravity plunger begins to descend, and the gravity plunger drops to the lowest point. , the air pressure inside the air storage chamber begins to decrease, and the control pressure liquid is discharged at the same time.

Additional aspects and advantages of the present application will be set forth, in part, in the following description, and in part will be apparent from the following description, or learned by practice of the present application.

Description of drawings

The above and/or additional aspects and advantages of the present application will become apparent and readily understood from the following description of embodiments taken in conjunction with the accompanying drawings, wherein:

1 is a schematic structural diagram of a gravity compressed air energy storage system with low pressure differential sealing proposed in an embodiment of the present application;

2 is a schematic structural diagram of a gravity compressed air energy storage system with low differential pressure sealing proposed by another embodiment of the present application;

3 is a schematic structural diagram of a sealing film proposed by another embodiment of the present application;

4 is a schematic structural diagram of a gravity compressed air energy storage system with low differential pressure sealing proposed by another embodiment of the present application;

5 is a schematic structural diagram of a gravity compressed air energy storage system with low differential pressure sealing proposed by another embodiment of the present application;

Fig. 6 is the partial structure schematic diagram of Fig. 5 of the present application;

7 is a schematic structural diagram of a low differential pressure sealed gravity compressed air energy storage system proposed by another embodiment of the present application;

In the figure: 1, shaft; 2, gravity plunger; 201, locking assembly; 202, pressure bearing cylinder; 203, filling gravity block; 204, positioning guide groove; 205, support ring; 3, sealing film; 301, support rib ; 302, elastic sealing membrane; 4, air storage chamber; 5, regulating chamber; 501, pressure fluid; 6, pressure fluid storage device; 601, liquid inlet pipeline; 602, liquid feeding pump; 603, liquid outlet pipeline; 604, drain pump; 7, ground gravity assembly; 701, support platform; 702, gravity block group; 703, ground gravity block; 8, first guide rail; 9, second guide rail; 10, air compressor unit; 11, air expansion unit.

Detailed ways

The following describes in detail the embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, but should not be construed as a limitation on the present application. On the contrary, the embodiments of the present application include all changes, modifications and equivalents falling within the spirit and scope of the appended claims.

FIG. 1 is a schematic structural diagram of a gravity compressed air energy storage system with a low differential pressure sealed according to an embodiment of the present application.

Referring to FIG. 1, a low-pressure differential sealed gravity compressed air energy storage system includes a shaft 1, a gravity plunger 2 is movably inserted in the shaft 1, and there is a gap between the shaft 1 and the gravity plunger 2, and a seal is arranged in the gap. Membrane 3, the sealing membrane 3 is in a sealed connection with the shaft 1 and the gravity plunger 2, so that the gravity plunger 2, the sealing membrane 3 and the space below the shaft 1 form an air storage cavity 4, and the air storage cavity 4 is used to store compressed air. The space between the sealing film 3, the gravity plunger 2 and the shaft 1 above the sealing film 3 forms a regulating cavity 5. The regulating cavity 5 is filled with a pressure liquid 501, and the pressure liquid 501 is opposite to the sealing film. 3 has a downward pressure, the compressed air in the air storage chamber 4 has a greater pressure on the sealing film 3, and the downward force of the pressure liquid 501 can reduce the pressure difference between the upper and lower pressure of the sealing film 3, and then the tensile stress received is reduced , thereby reducing the cost of composite materials and improving the life of the sealing material of the air storage cavity 4 .

As shown in FIG. 2 , in some embodiments, a pressure liquid storage device 6 is also included, and the pressure liquid storage device 6 is connected to the adjustment chamber 5 , so that when the pressure of the compressed air in the air storage chamber 4 increases, the pressure liquid storage device passes through the pressure liquid storage device to the adjustment chamber. 5, the pressure liquid 501 is introduced to reduce the pressure difference of the sealing membrane 3, wherein the bottom of the pressure liquid storage device 6 is connected with a liquid inlet pipe 601, and one end of the liquid inlet pipe 601 is connected to the shaft 1 and communicated with the adjustment chamber 5 , wherein the liquid inlet pipe 601 is provided with a liquid inlet valve and a liquid feeding pump 602, the top of the pressure liquid storage device 6 is connected with a liquid outlet pipe 603, one end of the liquid outlet pipe 603 is connected to the shaft 1, and the liquid outlet pipe 603 is communicated with the adjustment chamber 5, and the liquid inlet of the liquid outlet pipe 603 is set close to the sealing film 3, so that the pressure liquid 501 above the sealing film 3 can enter the liquid outlet pipe 603, and the liquid outlet pipe 603 is provided with an outlet. The liquid valve and the liquid discharge pump 604 make the compressed air flow into the air storage chamber 4, so that when the pressure in the air storage chamber 4 increases, the upward pressure on the sealing membrane 3 increases. , the pressure liquid 501 exerts downward pressure on the sealing membrane 3 , thereby effectively reducing the upper and lower pressure difference on the sealing membrane 3 .

As shown in FIG. 3 , in some embodiments, the sealing film 3 is a cylindrical structure, and the sealing film 3 includes a plurality of supporting ribs 301 , and the plurality of supporting ribs 301 surround the peripheral side of the cylindrical structure. They are connected by the elastic sealing film 302 to form a cylindrical structure by a plurality of supporting ribs 301 and the elastic sealing film 302. By setting the supporting ribs 301, the longitudinal tensile strength of the sealing film can be improved, and the air storage chamber 4 is filled with constant pressure. When the sealing film 3 is closed, the elastic area of the elastic sealing film 302 of the sealing film 3 bulges to the low pressure side, and fits with the wall surface of the shaft 1 and the gravity plunger 2 to provide a reverse support force and reduce the annular tension of the sealing film. In addition, the gravity plunger 2 When moving to different heights, the different bending positions of the sealing film 3 cause the sealing film 3 to produce its own extrusion deformation, which will reduce the service life of the sealing film 3, and the performance of the material of the sealing film 3 needs to be improved, which will increase the cost. The arrangement of the sealing film 3 between the two adjacent support ribs 301 can provide the inward deformation allowance of the sealing film 3 , reduce the internal stress of the sealing film 3 caused by the deformation, improve the service life of the sealing film 3 and reduce the material cost of the sealing film 3 .

In addition, the top end of the sealing membrane 3 is bent inward to form an inner ring and an outer ring, the inner ring is connected with the top end of the outer ring, the bottom end of the inner ring is sealingly connected to the outer wall of the gravity plunger 2, and the bottom end of the outer ring is connected On the inner wall of the shaft 1, the outer diameter of the outer ring is the same as the inner diameter of the shaft 1, so that the support ribs 301 and the elastic sealing film 302 of the outer ring are connected to the inner wall of the shaft 1, and the support ribs 301 of the inner ring are connected to the gravity plunger 2 When the air storage chamber 4 is inflated, under the action of pressure, the elastic sealing film 302 bulges to the low pressure side, so that the elastic sealing film 302 can also be connected with the outer wall of the gravity plunger 2 . At the same time, when the sealing film 3 is folded to form an inner ring and an outer ring, wrinkles are formed on the peripheral side of the folded inner ring, and the wrinkles are squeezed against each other, which will cause self-extrusion deformation, generate internal stress, and affect the sealing film 3. Service life, by setting the supporting ribs 301 and fixing by the supporting ribs 301, after the elastic sealing film 302 is wrinkled and raised, the interval between the two adjacent wrinkled protrusions through the supporting ribs 301 will not produce extrusion and internal stress, Thus, the material cost of the sealing film 3 is reduced.

4, in some embodiments, the top of the gravity plunger 2 is provided with a locking assembly 201, so that the gravity plunger 2 moving downward is supported on the ground at the top of the shaft 1 by the locking assembly 201, so that the gravity plunger 2 At the bottom limit, there is a certain space in the air storage chamber 4 . In the initial stage, the compressed air contained in the air storage chamber 4 has sufficient pressure to lift the gravity plunger 2 to realize the start of the gravity plunger 2 .

In addition, an above-ground gravity assembly 7 can be provided on the top of the gravity plunger 2, that is, the gravity part is divided into two parts, the gravity plunger 2 arranged underground and the above-ground gravity assembly 7 arranged on the ground, both the above-ground part and the underground part can provide Gravity, to achieve more energy storage, and by arranging the above-ground gravity component 7 directly outside the shaft 1, when realizing large energy storage, it is not necessary to concentrate all the gravity parts in the shaft 1, which can reduce the height of the shaft 1, greatly The excavation engineering volume and engineering difficulty of the shaft 1 are reduced.

5 and 6, in some embodiments, the ground gravity assembly 7 includes a support table 701 and a plurality of gravity block groups 702 arranged on the support table 701, and the plurality of gravity block groups 702 are equiangularly distributed on the gravity plunger 2 On the peripheral side, the support table 701 is arranged on the top of the gravity plunger 2, so as to apply a downward force to the gravity plunger 2 through the support table 701 and the plurality of gravity block groups 702, that is, the same gravity When the block groups 702 are equiangularly distributed on the circumference of the gravity plunger 2, since the gravity plunger 2 is a cylindrical structure, the axis of the cylindrical structure surrounded by the plurality of gravity block groups 702 coincides with the axis of the gravity plunger 2, And it is ensured that the center of gravity of the support table 701 is on the axis of the gravity plunger 2, so that the center of gravity of the entire ground gravity assembly 7 is on the axis of the gravity plunger 2, by dividing the ground gravity assembly 7 into the support table 701 and scattered on the support table. The multiple gravity block groups 702 on the 701 avoid that the multiple gravity block groups 702 are directly applied to the support table 701 by stacking upwards when the above-ground gravity assembly 7 has a certain gravity requirement, resulting in a high stacking height and increasing construction difficulty. and risk issues.

In some embodiments, a plurality of first guide rails 8 are further included, and the plurality of first guide rails 8 are distributed on the peripheral side of the support table 701 . The peripheral side of the support table 701 is provided with a first guide component that cooperates with the first guide rails 8 to pass The first guide rail 8 limits the position of the support table 701 and the gravity plunger 2, so that the support table 701 and the gravity plunger 2 will not tilt during the up and down movement. A guide rail 8 is equiangularly distributed on the peripheral side of the support platform 701 , a plurality of well towers are arranged on the ground at the top of the shaft 1 , and the first guide rail 8 is installed on the well tower.

It should be noted that, each gravity block group 702 may have various structures.

As a possible structure, each gravity block group 702 may include a plurality of superimposed above-ground gravity blocks 703, and setting the gravity block group 702 into a plurality of superimposed above-ground gravity blocks 703 reduces the weight of each hoisting during construction and hoisting , convenient for hoisting construction. A plurality of second guide rails 9 are arranged on the support table 701 on the peripheral side of the gravity block group 702, and each gravity block group 702 on the support table 701 is provided with a plurality of well towers, and a plurality of above-ground gravity blocks 703 are connected. The outer wall of the topmost ground gravity block 703 is provided with a second guide assembly that cooperates with the second guide rail 9, so as to limit the position of the multiple ground gravity blocks 703 on each gravity block group 702 through the second guide rail 9, After the installation of the multiple ground gravity blocks 703, the center of gravity is concentrated on the cylindrical axis surrounded by the multiple second guide rails 9, so that the center of gravity of the multiple gravity block groups 702 can be controlled to be evenly distributed on the periphery of the gravity plunger 2, Make the force on the 2 sides of the gravity plunger evenly, that is to say, you can tighten the multiple ground gravity blocks 703 with bolts, adjust the level between the blocks, and then place the top gravity block on the ground. A secondary guide assembly is installed on the side wall of 703, so that the gravity block group 702 will not be offset during the up and down movement, wherein the first guide assembly and the second guide assembly can be set as roller can ears.

As shown in FIG. 7 , in some embodiments, the gravity plunger 2 includes a pressure-bearing cylinder 202 and a plurality of superimposed filling gravity blocks 203 filled in the pressure-bearing cylinder 202 . The locking assembly 201 is arranged at the top of the pressure-bearing cylinder 202 to lock The component 201 can be a locking flange, the outer diameter of the locking flange is larger than the inner diameter of the pressure-bearing cylinder 202, and the inner wall of the pressure-bearing cylinder 202 is provided with a plurality of positioning guide grooves 204 along the axial direction, filling the outer wall of the gravity block 203. There is a positioning block matched with the positioning guide groove 204, so that the center of gravity of the plurality of filling gravity blocks 203 is on the axis of the pressure-bearing cylinder 202 through the limiting effect of the positioning guide groove 204, so as to prevent the filling gravity blocks 203 from being in the gravity plunger 2 The center offset occurs during the up and down movement, resulting in the center offset of the entire gravity plunger 2.

In detail, the pressure-bearing cylinder 202 can be a cylindrical structure surrounded by steel plates, and the surface is relatively smooth. In addition, the inner wall of the shaft 1 can also be fixed with a steel lining, and the sealing film 3 is connected to the inner wall of the steel lining and the outer wall of the pressure-bearing cylinder 202. By arranging the steel lining, the inner wall of the shaft can be ensured to be a smooth wall, so that the sealing performance can be improved when the sealing film 3 is fixed on the steel lining and the pressure-bearing cylinder 202. In addition, the interior of the pressure-bearing cylinder 202 is hollow, which reduces the weight and facilitates the Hoisting, hoisting into the shaft 1 and blocking by the locking assembly 201, and then hoisting a plurality of filling gravity blocks 203 into the pressure-bearing cylinder 202 in blocks. It can reduce the difficulty of hoisting. In addition, since the energy storage pressure in the air storage chamber 4 is relatively large, and the gravity blocks are generally made of concrete, air leakage will occur under the action of high-pressure air. The outside of 203 can improve air tightness and prevent air leakage, thereby ensuring the sealing characteristics of the air storage chamber 4, which can withstand higher pressure and improve the energy density of the system energy storage.

In addition, it should be noted that a plurality of support rings 205 may be arranged on the inner wall of the pressure-bearing cylinder 202 along the axial direction, and the plurality of support rings 205 are arranged coaxially with the pressure-bearing cylinder 202. Since the pressure-bearing cylinder 202 is cylindrical The hollow structure can improve the performance and strength of the pressure-bearing cylinder 202 through the action of the plurality of support rings 205 , and then the positioning guide grooves 204 can be arranged on the support rings 205 .

In some embodiments, it also includes an air compressor unit 10 and an air expansion unit 11. Both the air compressor unit 10 and the air expansion unit 11 are connected to the air storage chamber 4, and the surplus power drives the air compressor unit 10 to perform work on the gas through the motor to compress the gas. The air is introduced into the air storage chamber 4, and the pressure-bearing cylinder 202 is moved upward by the compressed air pressure to realize energy storage. When the energy is released, the compressed air in the air storage chamber 4 is introduced into the air expansion unit 11 to perform work and transform into for electrical energy.

A low-pressure differential sealed gravity compressed air energy storage method, comprising the following methods:

The sealing film 3 is sealed and installed between the gravity plunger 2 and the shaft 1, so that the space between the gravity plunger 2, the sealing film 3 and the shaft 1 located under the sealing film 3 forms an air storage chamber 4, and the sealing film 3, the gravity The space between the plunger 2 and the shaft 1 above the sealing membrane 3 encloses a regulating cavity 5;

When storing energy, the electric motor drives the air compressor unit 10 to do work, and the compressed air obtained by doing the work is passed into the air storage cavity 4, the air pressure in the air storage cavity 4 gradually increases, and the pressure liquid 501 is introduced into the adjustment cavity 5 at the same time. , when the pressure in the air storage chamber 4 increases, the amount of the pressure liquid 501 introduced also increases, maintaining the internal and external pressure difference of the sealing membrane 3, and when the pressure in the air storage chamber 4 increases to the target pressure, push the gravity plunger 2 Move up to the highest limit to stop;

When the energy is released, the high-pressure air in the air storage chamber 4 does work to the air expansion unit 11, driving the motor to generate electricity, the gravity plunger 2 moves downward, the air storage capacity in the air storage chamber 4 decreases, the gravity plunger 2 begins to descend, and the gravity column When the plug 2 drops to the lowest point, the air pressure inside the air storage chamber 4 begins to decrease, the drain pump 604 is turned on, the pressure liquid 501 is controlled to discharge, and the liquid level of the pressure solution 501 decreases. When the air pressure inside the air storage chamber 4 drops to normal pressure, The pressure difference between the inside and outside of the sealing membrane 3 is kept constant.

It should be noted that, in the description of the present application, the terms "first", "second" and the like are only used for the purpose of description, and should not be construed as indicating or implying relative importance. Also, in the description of this application, unless otherwise specified, "plurality" means two or more.

In the description of this specification, description with reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples", etc., mean specific features described in connection with the embodiment or example , structure, material or feature is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limitations to the present application. Embodiments are subject to variations, modifications, substitutions and variations.

Claims (9)

1. a low-pressure differential sealed gravity compressed air energy storage system, is characterized in that, comprises: a vertical shaft, a gravity plunger is movably inserted in the vertical shaft, and there is a gap between the vertical shaft and the gravity plunger; a sealing membrane, the sealing membrane being located in the gap, the sealing membrane being in a sealed connection with the shaft and the gravity plunger, so that the gravity plunger, the sealing membrane and the shaft are located in the The space below the sealing film is surrounded by an air storage chamber, the air storage chamber is used for storing compressed air, and the space above the sealing film is surrounded by the sealing film, the gravity plunger and the shaft above the sealing film an adjustment cavity, into which a pressure liquid is introduced, and the pressure liquid exerts downward pressure on the sealing film; the sealing film is a cylindrical structure, and the sealing film includes a plurality of supporting ribs, a plurality of The supporting ribs surround the peripheral side of the cylindrical structure, and two adjacent supporting ribs are connected by an elastic sealing film, so as to form a cylindrical structure by a plurality of the supporting ribs and the elastic sealing film; The top end of the sealing membrane is bent inward to form an inner ring and an outer ring, the inner ring is connected with the top end of the outer ring, the bottom end of the inner ring is sealingly connected to the outer wall of the gravity plunger, and the outer ring is connected to the outer wall of the gravity plunger. The bottom end of the ring is attached to the inner wall of the shaft. 2 . The low differential pressure sealed gravity compressed air energy storage system according to claim 1 , further comprising a pressure liquid storage device, the pressure liquid storage device is connected to the adjustment chamber, so that the storage device can be stored. 3 . When the pressure of the compressed air in the air cavity increases, the pressure liquid is introduced into the adjustment cavity through the pressure liquid storage device to reduce the pressure difference of the sealing membrane. 3 . The low differential pressure sealed gravity compressed air energy storage system according to claim 1 , wherein the outer diameter of the outer ring is the same as the inner diameter of the shaft, so that the support ribs of the outer ring and the elastic sealing film is connected with the inner wall of the shaft; The support ribs of the inner ring are connected with the outer wall of the gravity plunger. 4 . The gravity compressed air energy storage system with low pressure differential seal according to claim 1 , wherein the top end of the gravity plunger is provided with a locking assembly, so as to pass all the downward moving parts through the locking assembly. 5 . The gravity plunger is supported on the ground at the top of the shaft, so that there is a certain space in the air storage cavity when the gravity plunger is at the bottom limit position; The top of the gravity plunger is provided with an above-ground gravity component, and the above-ground gravity component is located outside the shaft. 5 . The low differential pressure sealed gravity compressed air energy storage system according to claim 4 , wherein the above-ground gravity assembly comprises a support table and a plurality of gravity block groups arranged on the support table, and the support The platform is fixed on the top of the gravity plunger, and a plurality of the gravity block groups are equiangularly distributed on the peripheral side of the gravity plunger. 6 . The low-pressure differential sealed gravity compressed air energy storage system according to claim 5 , further comprising a plurality of first guide rails, and the plurality of first guide rails are distributed on the peripheral side of the support table; 7 . The peripheral side of the support table is provided with a first guide component matched with the first guide rail, so as to limit the position of the support table and the gravity plunger through the first guide rail. 7. The low-pressure differential sealed gravity compressed air energy storage system according to claim 6, wherein the gravity block group comprises a plurality of superimposed above-ground gravity blocks; A plurality of second guide rails are arranged on the support table on the peripheral side of the gravity block group, and a plurality of the above-ground gravity blocks are connected. The second guide assembly is matched with the second guide rail to limit the position of the plurality of the ground gravity blocks on each of the gravity block groups through the second guide rail. 8 . The gravity compressed air energy storage system with low differential pressure sealing according to claim 4 , wherein the gravity plunger comprises a pressure-bearing cylinder and a plurality of superimposed fillings filled in the pressure-bearing cylinder. 9 . gravity block; the locking assembly is arranged on the top end of the pressure-bearing cylinder; The inner wall of the pressure-bearing cylinder is provided with a plurality of positioning guide grooves along the axial direction, and the outer wall of the filling weight block is provided with a positioning block matched with the positioning guide groove, so as to pass the limit of the positioning guide groove. The position action makes the center of gravity of the plurality of filling gravity blocks on the axis of the pressure-bearing cylinder. 9. An energy storage method based on the low pressure differential sealed gravity compressed air energy storage system according to any one of claims 1-8, characterized in that, comprising the following methods: The sealing film is sealed between the gravity plunger and the shaft, so that the space between the gravity plunger, the sealing film and the shaft under the sealing film encloses an air storage cavity, and the sealing film, the gravity plunger and the shaft are located in the sealing film An adjustment cavity is formed between the space above; When storing energy, the electric motor drives the air compressor unit to do work, and the compressed air obtained from the work is passed into the air storage cavity, the air pressure in the air storage cavity gradually increases, and pressure liquid is introduced into the adjustment cavity, and the air storage cavity When the pressure increases, the amount of pressure liquid introduced also increases, maintaining the internal and external pressure difference of the sealing membrane. When the pressure in the air storage chamber increases to the target pressure, push the gravity plunger to move up to the highest limit and stop; When the energy is released, the high-pressure air in the air storage chamber does work to the air expansion unit, which drives the motor to generate electricity, the gravity plunger moves downward, the air storage volume in the air storage chamber decreases, the gravity plunger begins to descend, and the gravity plunger drops to the lowest point. , the air pressure inside the air storage chamber begins to decrease, and the control pressure liquid is discharged at the same time.

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