CN115208071A

CN115208071A - Gravity compressed air energy storage system comprising liquid vibration damper

Info

Publication number: CN115208071A
Application number: CN202210796101.9A
Authority: CN
Inventors: 文军; 王超; 李阳; 张社荣; 王枭华; 赵瀚辰; 杨成龙; 于在松
Original assignee: Tianjin University; Xian Thermal Power Research Institute Co Ltd; Huaneng Group Technology Innovation Center Co Ltd
Current assignee: Tianjin University; Xian Thermal Power Research Institute Co Ltd; Huaneng Group Technology Innovation Center Co Ltd
Priority date: 2022-07-07
Filing date: 2022-07-07
Publication date: 2022-10-18

Abstract

The invention provides a gravity compressed air energy storage system comprising a liquid vibration damper, which comprises: the device comprises a vertical shaft, a gravity assembly is movably inserted in the vertical shaft, a gap is formed between the outer wall of the gravity assembly and the inner wall of the vertical shaft, a sealing film is arranged in the gap, and the sealing film is hermetically connected with the outer wall of the gravity assembly and the inner wall of the vertical shaft, so that an air storage chamber is enclosed among the sealing film, the space of the vertical shaft below the sealing film and the gravity assembly; and a liquid damper assembly; comprising a tank containing a volume of liquid; the water tank is arranged above the gravity assembly, and energy generated by shaking of liquid in the water tank is used for dissipating energy generated by vibration of the gravity assembly. The technical scheme in the embodiment of the invention solves the problem of how to ensure the stable operation of the gravity pressing block under the conditions of wind load, earthquake load and the like.

Description

Gravity compressed air energy storage system comprising liquid vibration damper

Technical Field

The invention relates to the technical field of pressure containers and air energy storage, in particular to a gravity compressed air energy storage system comprising a liquid vibration damping device.

Background

The gravity compressed air energy storage system converts redundant electric energy into gravitational potential energy through the air compressor, and the gravitational potential energy is converted into electric energy through the air pressure generator in a peak power utilization period. During energy storage, the compressed air energy storage system consumes electric energy to compress air and store the air in the air storage chamber, the top plate of the air storage chamber is lifted, and the lifting force is pressed; when energy is released, high-pressure air is released from the air storage chamber, and the gravity pressing block descends along with the top plate of the air storage chamber. The operation of the gravity compressed air energy storage system is in a complex occurrence environment, and when the weight blocks and the tower above the ground are subjected to adverse factors such as wind load, earthquake load and the like, serious consequences and immeasurable damage can be caused. How to ensure the stable operation of the gravity pressing block under the conditions of wind load, earthquake load and the like is a problem to be solved urgently at present.

Disclosure of Invention

The present invention is directed to solving, at least to some extent, one of the technical problems in the related art.

Therefore, the invention aims to provide a gravity compressed air energy storage system comprising a liquid vibration damper, which dissipates the energy of the vibration of a gravity pressing block structure through the energy generated by the shaking of the liquid in a water tank, and can avoid the internal consumption caused by irregular shaking of water flow in the water tank by arranging a well-shaped partition plate, thereby improving the vibration damping effect, ensuring that the height of the liquid in the water tank is one third of the height of the water tank and fully playing the vibration damping effect. In addition, the water tank and the top gravity pressing block are connected into a whole through guiding and do lifting motion along with the gravity pressing block, so that the water tank has a vibration reduction effect on the gravity pressing block at any height.

In order to achieve the above object, the present invention provides a gravity compressed air energy storage system including a liquid vibration damping device, comprising:

the device comprises a vertical shaft, a gravity assembly is movably inserted in the vertical shaft, a gap is formed between the outer wall of the gravity assembly and the inner wall of the vertical shaft, a sealing film is arranged in the gap, and the sealing film is hermetically connected with the outer wall of the gravity assembly and the inner wall of the vertical shaft, so that an air storage chamber is enclosed among the sealing film, the space of the vertical shaft below the sealing film and the gravity assembly; and

a liquid damper assembly; it comprises a tank containing a volume of liquid; the water tank is arranged above the gravity assembly, and energy generated by shaking of liquid in the water tank dissipates energy generated by vibration of the gravity assembly.

In some embodiments, the liquid dampening assembly includes a diaphragm; the water tank is divided into a plurality of containing cavities through the partition plate, and the adjacent containing cavities are communicated to realize that the liquid levels of liquid in the containing cavities are flush.

In some embodiments, the liquid dampening assembly includes a protective cover; the protective cover is arranged at the top of the water tank and used for preventing liquid from evaporating.

In some embodiments, the level of liquid in the tank is no less than one third of the tank height.

In some embodiments, the liquid shock assembly comprises a fixed assembly; the fixing assembly comprises a fixing groove, and the water tank is arranged in the fixing groove to realize that the water tank moves up and down along with the gravity assembly.

In some embodiments, the gravity assembly comprises a gravity block set and a pressure bearing assembly; the gravity block group is arranged at the top of the pressure-bearing assembly and comprises a plurality of gravity pressing blocks which are stacked layer by layer in the vertical direction; the bottom of the pressure bearing assembly extends into the shaft, and the outer wall of the pressure bearing assembly is connected with the sealing film; the top of the bearing assembly is located on the ground at the top of the shaft.

In some embodiments, the pressure bearing assembly comprises a pressure bearing cylinder and a pressure bearing base; the bottom of the pressure bearing cylinder extends into the shaft, and the top of the pressure bearing cylinder is provided with the pressure bearing base; the gravity block group is positioned above the pressure-bearing base, so that the pressure-bearing cylinder is supported on the ground on the peripheral side of the top of the vertical shaft through the pressure-bearing base when moving downwards to the lowest limit position.

In some embodiments, the energy storage system includes a guide device including a guide slot and a roller; the guide grooves are distributed on the periphery of the gravity component and are arranged on the inner wall of the vertical shaft or the outer part of the vertical shaft; the roller is matched with the guide groove and is connected with the groove bottom of the guide groove, so that the roller moves up and down along the groove bottom of the guide groove when the gravity assembly moves up and down.

In some embodiments, a plurality of tower structures are arranged on the ground around the top of the shaft, and the guide grooves are respectively arranged on the tower structures.

In some embodiments, the guide means is provided on each of the plurality of gravity pressing blocks and the fixing groove; the guide device on the gravity pressing block is positioned between the gravity pressing block and the tower structure opposite to the gravity pressing block; the guide means on the securing slot are located between the securing slot and the tower structure opposite the securing slot.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The foregoing and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic diagram of a gravity compressed air energy storage system according to an embodiment of the present invention;

FIG. 2 is a schematic view of a fluid shock assembly according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a guiding device according to an embodiment of the present invention;

in the figure, 1, gravity briquetting; 2. a tower structure; 3. a guide device; 4. a pressure-bearing base; 5. a water tank; 6. a partition plate; 7. a soil layer; 8. a sealing film; 9. a liquid; 10. a pressure-bearing cylinder; 11. an air storage chamber; 12. a shaft; 13. a steel lining; 14. fixing grooves; 15. a communicating hole; 16. a roller; 17. and a guide groove.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention. On the contrary, the embodiments of the invention include all changes, modifications and equivalents coming within the spirit and terms of the claims appended hereto.

Referring to fig. 1-3, a gravity compressed air energy storage system including a liquid damper according to an embodiment of the present invention includes a shaft 12 and a liquid damper assembly; the vertical shaft 12 is formed by downward digging in the soil layer 7, the gravity assembly is movably inserted in the vertical shaft 12, a gap is formed between the outer wall of the gravity assembly and the inner wall of the vertical shaft 12, the sealing film 8 is arranged in the gap, and the sealing film 8 is connected with the outer wall of the gravity assembly and the inner wall of the vertical shaft 12 in a sealing manner, so that the sealing film 8 and the vertical shaft 12 are positioned in a space below the sealing film 8 and form the air storage chamber 11 between the gravity assembly.

In addition, the gravity compressed air energy storage system further comprises an air compression unit, an air expansion unit and a generator; an inlet of the air compression unit is connected with an air inlet device, an outlet of the air compression unit is connected with an inlet of the air storage chamber 11 through an energy storage pipeline, an outlet of the air storage chamber 11 is connected with an inlet of the air expansion unit through an energy release pipeline, and an outlet of the air expansion unit is connected with the generator; a heat exchange unit is arranged between the energy storage pipeline and the energy release pipeline. The exemplary air compression unit can be provided with a plurality of stages of air compressors according to actual needs; the air expansion unit can be provided with a plurality of stages of expanders according to actual needs.

The energy release pipeline is provided with a flow detection device, a pressure detection device and an adjusting valve, and the flow detection device, the pressure detection device and the adjusting valve are respectively connected with a control unit of the gravity compressed air energy storage system to monitor and control key parameters of the system in real time.

The gravity compressed air energy storage system in this embodiment is in operation:

the gravity compressed air energy storage system stores energy in a power grid electricity utilization valley period, an energy release pipeline is closed, an energy storage pipeline is opened, air enters an air compression unit through an air inlet device and is compressed into compressed air, generated heat is stored in a heat exchange unit, the compressed air enters an air storage chamber 11 through the energy storage pipeline, the volume of the air storage chamber 11 is increased, a gravity press block 1 is lifted by the compressed air at a constant pressure, and electric energy is converted into compressed air energy and gravitational potential energy of the gravity press block 1;

during the peak period of power utilization of the power grid, the compressed air energy storage system releases energy, the energy release pipeline is opened, the energy storage pipeline is closed, the gravity pressing block 1 descends, the volume of the air storage chamber 11 is reduced, compressed air is heated by the heat exchange unit and then enters the air expansion unit through the energy release pipeline to do work at a constant pressure and drive the generator to generate power, and the compressed air energy and the gravity potential energy of the gravity pressing block 1 are converted into electric energy.

In some embodiments, as shown in fig. 2, the liquid damping assembly comprises a water tank 5 with a certain accommodating space, and the water tank 5 is arranged above the gravity assembly and has a certain weight, which can replace the weight of the gravity press block 1 in part of the gravity assembly, so as to reduce the manufacturing cost of the gravity press block 1; advantageously, water tank 5 adopts the glass steel preparation to form, and the weight of water tank 5 is the same with the weight of gravity briquetting 1 simultaneously, slows down 5 gravity subassemblies of water tank and makes the lifting motion in-process break away from for water tank 5 all has the damping effect to gravity briquetting 1 at arbitrary height.

The liquid 9 with a certain volume is contained in the water tank 5, optionally, the liquid level of the liquid 9 in the water tank 5 is not less than one third of the height of the water tank 5, preferably, the liquid level of the liquid 9 in the water tank 5 is one third of the height of the water tank 5, so that the movement of the liquid 9 in the water tank 5 is mainly near the surface of the upper layer, and the liquid 9 on the lower layer is relatively static, in addition, the free liquid level of the water tank 5 is too large, and the damping effect of a wave-generating crushing surface is easily lost, therefore, the embodiment dissipates the energy generated by the shaking of the liquid 9 in the water tank 5 according to the damping principle of a tuned liquid 9 damper. The liquid 9 in the water tank 5 may be clear water, salt water, or other liquid 9 with low viscosity, such as antifreeze, for example. The liquid 9 is advantageously an anti-freezing liquid, because it has anti-freezing properties in winter, anti-evaporation in summer, anti-scaling, anti-corrosion, etc. all the year round.

In some embodiments, the liquid damping assembly comprises a diaphragm 6; the water tank 5 is divided into a plurality of accommodating cavities by the plurality of partition plates 6; the number of the partition plates 6 is four, two partition plates 6 are arranged side by side in the horizontal direction, and two partition plates 6 are arranged side by side in the direction perpendicular to the two partition plates 6 in the horizontal direction, so that the four partition plates 6 are in a shape of a Chinese character 'jing' in the horizontal plane, and the water tank 5 is divided into nine accommodating cavities by welding between the partition plates 6, and the nine accommodating cavities are similar to a nine-square grid shape. The communicating holes 15 are formed in the partition plates 6 between the adjacent containing cavities, and the liquid 9 in the adjacent containing cavities can be communicated, namely the containing cavities form a communicating device, so that the liquid level height of the liquid 9 in each containing cavity is ensured to be the same. When the gravity compressed air energy storage system engineering encounters wind load and earthquake load, the energy generated by the liquid 9 shaking in the water tanks 5 of the plurality of accommodating cavities dissipates the energy of the self-vibration of the gravity press block 1 structure; and in the process that the water tank 5 shakes, the partition plate 6 of the water tank 5 can avoid internal consumption caused by irregular shaking of water flow in the water tank 5, so that the vibration reduction effect is improved. After the liquid 9 in the water tank 5 is shaken, the liquid level of each accommodating cavity in the water tank 5 is restored to the free liquid level through the communication holes 15 between the partition plates 6. Wherein the liquid 9 in the water tank 5 should be replaced regularly in order to ensure the quality of the liquid 9 in the water tank 5. Advantageously, during long-term gravity compressed air energy storage system operation down water tank 5 exposes in the complex environment, can be equipped with the black protection casing at water tank 5 top, wherein the protection casing is the glass cover, prevents that liquid 9 in the water tank 5 from evaporating, influencing liquid 9 damping effect.

In some embodiments, the liquid shock assembly includes a fixed assembly; fixed subassembly includes fixed slot 14, the steel bay of exemplary fixed slot 14 for having certain intensity and thickness, water tank 5 sets up in the steel bay, the steel bay realizes improving water tank 5 through the parcel to water tank 5 and resists deformability, rectangle steel bay parcel water tank 5 simultaneously, water tank 5 also can be along with gravity assembly's lift and fall the elevating movement of vertical direction, guarantee that water tank 5 can not gravity assembly again and do the elevating movement in-process and break away from, make water tank 5 all have the damping effect to gravity clamp block 1 at arbitrary height.

In some embodiments, the gravity assembly includes a set of gravity blocks and a pressure bearing assembly; wherein the gravity block group is arranged at the top of the pressure-bearing assembly; the bottom of the pressure-bearing assembly extends into the vertical shaft 12, and the outer wall of the pressure-bearing assembly is connected with the sealing film 8; the top of the bearing assembly is located on the ground at the top of the shaft 12; the gravity block group comprises a plurality of gravity pressing blocks 1 which are stacked layer by layer in the vertical direction, and the gravity centers of the gravity pressing blocks 1 are always in the same vertical direction.

Specifically, as shown in fig. 1, the gravity assembly is divided into an aboveground gravity block group and a pressure-bearing assembly, wherein the bottom end of the gravity assembly extends into the vertical shaft 12, the sealing film 8 is directly connected with the bottom end of the outer wall of the pressure-bearing assembly, and the gravity block group is positioned outside the vertical shaft 12, so that when large energy storage is realized, all gravity blocks do not need to be concentrated in the vertical shaft 12, the height of the vertical shaft 12 can be reduced, and the excavation engineering amount and the engineering difficulty of the vertical shaft 12 are greatly reduced.

In addition, the gravity block group comprises a plurality of gravity pressing blocks 1 which are stacked in the vertical direction layer by layer, the gravity block group is arranged into the plurality of stacked gravity pressing blocks 1, the weight of each gravity pressing block 1 is reduced, the large energy storage is met, meanwhile, the hoisting difficulty is reduced, the pressure bearing assembly is hoisted to the vertical shaft 12 firstly in the hoisting construction process, the upper end of the pressure bearing assembly is supported on the ground on the peripheral side of the vertical shaft 12, and then the gravity pressing blocks 1 are hoisted layer by layer at the top of the pressure bearing assembly.

In some embodiments, the pressure bearing assembly comprises a pressure bearing cartridge 10 and a pressure bearing base 4; wherein the bottom of the pressure-bearing cylinder 10 extends into the vertical shaft 12, and the top of the pressure-bearing cylinder is provided with a pressure-bearing base 4; the gravity block group is positioned above the pressure bearing base 4, so that the pressure bearing cylinder 10 is supported on the ground at the top of the vertical shaft 12 through the pressure bearing base 4 when moving downwards to the lowest limit position.

Specifically, as shown in fig. 1, the pressure-bearing assembly comprises a pressure-bearing cylinder 10 and a pressure-bearing base 4, wherein the bottom end of the pressure-bearing cylinder 10 extends into the vertical shaft 12, the sealing film 8 is directly connected with the bottom end of the outer wall of the pressure-bearing cylinder 10, the top of the pressure-bearing cylinder 10 is positioned on the ground at the top of the vertical shaft 12 and is connected with the pressure-bearing base 4, a plurality of gravity pressing blocks 1 which are stacked layer by layer in the vertical direction are arranged above the pressure-bearing base 4, and the gravity centers of the gravity pressing blocks 1 are always in the same vertical direction.

In some embodiments, the energy storage system comprises a guide 3 comprising a guide channel 17 and rollers 16; the guide grooves 17 are arranged in plurality, the guide grooves 17 are distributed on the peripheral side of the gravity component, and the guide grooves 17 are arranged on the inner wall of the vertical shaft 12 or outside the vertical shaft 12; the roller 16 is matched with the guide groove 17 and connected with the bottom of the guide groove 17, so that the roller 16 moves up and down along the bottom of the guide groove 17 when the gravity assembly moves up and down.

The specific guide groove 17 is provided in plurality, the plurality of guide grooves 17 are distributed on the periphery of the gravity assembly, and the guide groove 17 is arranged on the inner wall of the shaft 12 or outside the shaft 12, that is, the guide groove 17 can be arranged inside the shaft 12 or outside the shaft 12. The rollers 16 are arranged in a plurality of numbers, the rollers 16 are respectively installed on the periphery of the gravity assembly through rotating shafts, and the rollers 16 are connected with the groove bottom of the guide groove 17, so that the rollers 16 move up and down along the groove bottom of the guide groove 17 when the gravity assembly moves up and down.

It can be understood that, when the gravity assembly is located in the shaft 12 and moves in the energy storage process, a plurality of guide grooves 17 may be provided on the inner wall periphery of the shaft 12, for example, four

guide grooves

17,4 may be provided on the inner wall of the shaft 12 at equal angles, because the roller 16 on the gravity assembly is mounted on the inner wall periphery of the gravity assembly through a rotating shaft, the roller 16 may rotate on the gravity assembly, when the roller 16 is connected to the groove bottom of the guide groove 17, not only the position can be limited through the guide grooves 17, the guide grooves 17 cooperate with the roller 16 to restrict the movement direction of the gravity assembly, but also the gravity assembly vertically moves upwards or downwards along the direction of the guide grooves 17 at a certain speed, and periodically, a lubricant such as grease or graphite is added to the position where the guide grooves 17 contact with the roller 16, thereby reducing friction and improving the conversion rate of gravitational potential energy.

In addition, it is also possible that the ground outside the top end of the shaft 12 is provided with a plurality of tower structures 2, the tower structures 2 are distributed on the periphery of the shaft 12, the guide grooves 17 are respectively installed on the tower structures 2, that is, 4 tower structures 2 can be arranged, then the guide grooves 17 are arranged on the tower structures 2 outside the shaft 12, in the energy storage process, one part of the gravity component is located outside the shaft 12, the other part of the gravity component is located inside the shaft 12, and the outer wall of the gravity component located inside the shaft 12 is in sealing connection with the inner wall of the shaft 12 through the sealing film 8.

Illustratively, the plurality of gravity compacts 1 are each provided with a guide device 3 on the peripheral side, and the guide devices 3 are installed on the peripheral side of the gravity compacts 1 and are located between the gravity compacts 1 and the tower structure 2 opposite to the gravity compacts 1. Wherein, a gap is reserved between the outer side wall of the gravity press block 1 and the inner side wall of the tower, and a plurality of rollers 16 are respectively arranged on the peripheral side of the gravity block group and the peripheral side of the outer wall of the top end of the pressure-bearing cylinder 10, so that the overground gravity block group and the pressure-bearing cylinder 10 can move up and down along the guide groove 17 through the rollers 16 in the up-and-down moving process. Specifically, as shown in fig. 3. Every gravity briquetting 1's week side all opens there is the mounting groove, installs the steel sheet groove in the mounting groove, and gyro wheel 16 is arranged in the steel sheet groove, and the pivot of connecting on the gyro wheel 16 is installed between the lateral wall of the relative both sides in steel sheet groove, and here is no longer repeated for common structure setting.

In some embodiments, the guide 3 is disposed on the circumferential side of the fixing groove 14, and the guide 3 is welded on the circumferential side of the fixing groove 14 and is located between the fixing groove 14 and the tower structure 2 opposite to the fixing groove 14. Wherein, a gap is reserved between the outer side wall of the fixing groove 14 and the inner side wall of the tower, as shown in fig. 1 and fig. 2, a plurality of rollers 16 are respectively arranged on the peripheral side of the fixing groove 14 and the peripheral side of the outer wall of the top end of the pressure-bearing cylinder 10, so that the fixing groove 14 and the pressure-bearing cylinder 10 can move up and down along the guide groove 17 through the rollers 16 in the up-and-down moving process, and here, the arrangement of the guide device 3 on the peripheral side of the gravity press block 1 can be referred to, and details are not repeated. Preferably, the guide device 3 on the peripheral side of the gravity pressing block 1 and the guide device 3 on the peripheral side of the fixing groove 14 are of an integral structure, so that the water tank 5 can be effectively prevented from being separated in the pressing block movement process.

In some embodiments, a steel lining 13 is arranged on the inner wall of the shaft 12, the sealing membrane 8 is connected to the inner wall of the steel lining 13, the smooth wall surface of the inner wall of the shaft 12 can be ensured by arranging the steel lining 13, and the pressure bearing cylinder 10 is also of a cylindrical structure surrounded by steel plates and is also of a smooth outer wall surface structure, so that when the sealing membrane 8 is fixed on the steel lining 13 and the pressure bearing cylinder 10, the sealing performance of the sealing membrane 8 can be improved, and the installation of the sealing membrane 8 is facilitated.

The sealing performance of the connection with the sealing film 8 can be improved by providing the steel lining 13.

In addition, it should be noted that the pressure-containing cylinder 10 is filled with sand.

It can be understood that the pressure-bearing cylinder 10 can be a cylindrical structure surrounded by steel plates, the interior of the pressure-bearing cylinder is a hollow structure, the reduced weight is convenient to hoist, and in addition, the sand is filled in the pressure-bearing cylinder 10, so that the gravity of energy storage can be increased.

It should be noted that the terms "first," "second," and the like in the description of the present invention are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. In addition, in the description of the present invention, "a plurality" means two or more unless otherwise specified.

Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and alternate implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present invention.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above 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 embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims

1. A gravity compressed air energy storage system including a liquid damping device, comprising:

a liquid damper assembly; comprising a tank containing a volume of liquid; the water tank is arranged above the gravity assembly, and energy generated by shaking of liquid in the water tank is used for dissipating energy generated by vibration of the gravity assembly.

2. The energy storage system of claim 1, wherein the fluid shock assembly comprises a diaphragm; the water tank is divided into a plurality of containing cavities through the partition plate, and the adjacent containing cavities are communicated to realize that the liquid level of liquid in the containing cavities is flush.

3. The energy storage system of claim 1, wherein the liquid shock assembly comprises a protective cover; the protective cover is arranged at the top of the water tank and used for preventing liquid from evaporating.

4. The energy storage system of claim 1, wherein a level of liquid in the tank is no less than one third of the tank height.

5. The energy storage system of any of claims 1-4, wherein the liquid dampening assembly comprises a stationary assembly; the fixed assembly comprises a fixed groove, and the water tank is arranged in the fixed groove to realize that the water tank moves up and down along with the gravity assembly.

6. The energy storage system of claim 5, wherein the gravity assembly comprises a gravity block set and a pressure bearing assembly; the gravity block group is arranged at the top of the pressure-bearing assembly and comprises a plurality of gravity pressing blocks which are stacked layer by layer in the vertical direction; the bottom of the pressure bearing assembly extends into the shaft, and the outer wall of the pressure bearing assembly is connected with the sealing film; the top of the bearing assembly is located on the ground at the top of the shaft.

7. The energy storage system of claim 6, wherein the bearing assembly comprises a bearing cylinder and a bearing base; the bottom of the pressure bearing cylinder extends into the shaft, and the top of the pressure bearing cylinder is provided with the pressure bearing base; the gravity block group is positioned above the pressure-bearing base, so that the pressure-bearing cylinder is supported on the ground on the peripheral side of the top of the vertical shaft through the pressure-bearing base when moving downwards to the lowest limit position.

8. The energy storage system of claim 6, wherein the energy storage system comprises a guide device comprising a guide slot and a roller; the guide grooves are distributed on the periphery of the gravity component and are arranged on the inner wall of the vertical shaft or the outer part of the vertical shaft; the roller is matched with the guide groove and is connected with the groove bottom of the guide groove, so that the roller moves up and down along the groove bottom of the guide groove when the gravity assembly moves up and down.

9. The energy storage system of claim 8, wherein a plurality of tower structures are provided on the ground around the top of the shaft, and the plurality of guide grooves are respectively installed on the plurality of tower structures.

10. The energy storage system of claim 9, wherein a plurality of the gravity compacts and the fixing grooves are each provided with the guide means on a circumferential side; the guide device on the gravity pressing block is positioned between the gravity pressing block and the tower structure opposite to the gravity pressing block; the guide means on the fixation slot is located between the fixation slot and the tower structure opposite the fixation slot.