Energy storage system and heat storage and temperature regulation method of energy storage system

Abstract

The invention relates to the technical field of energy storage, in particular to an energy storage system and a heat storage and temperature adjustment method of the energy storage system. The energy storage system comprises a gas storage, a gas compression device and a gas expansion device; the gas storage is coupled with a first heat storage device, at least one part of the first heat storage device is arranged in the gas storage, and the first heat storage device exchanges heat with a gas medium in the gas storage; the gas compression device is connected with a gas inlet of the gas storage; the gas expansion device is connected with a gas outlet of the gas storage; when the gas medium enters the gas storage, the gas medium in the gas storage exchanges heat with the first heat storage device, so that the temperature of the gas medium is reduced; and when the gas medium is discharged out of the gas storage, the gas medium in the gas storage exchanges heat with the first heat storage device, so that the temperature of the gas medium rises.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage, and particularly to an energy storage system and a heat storage and temperature regulation method for the energy storage system. Background Art

[0002] With the overuse of fossil fuels, environmental problems are becoming increasingly severe. How to develop a green and low-carbon economy has become a common problem faced by countries around the world. Under the background of "dual carbon", the proportion of new energy power generation mainly based on wind and light will increase significantly. However, the inherent randomness and instability of new energy lead to difficulties in grid connection and consumption, posing a huge challenge to the safety and stability of the power system. Therefore, finding an energy storage method that can achieve low-cost peak shaving and valley filling and balance power load has become a research hotspot. At present, only pumped storage and compressed air energy storage can achieve commercial large-scale operation.

[0003] Compared with pumped storage power stations, compressed air energy storage power stations have flexible site selection, loose environmental requirements, and short construction periods, and have good market prospects. The basic principle of compressed air energy storage is to convert electrical energy into the potential energy of air by a compressor and store it. When needed, the potential energy of air is converted into electrical energy by a turbine and transmitted to the power grid. The gas storage reservoir is used to store high-pressure air and is an important device for compressed air energy storage. At present, the gas storage reservoirs of compressed air energy storage power stations are mainly artificial chambers and abandoned salt caverns.

[0004] When high-pressure gas enters the gas storage reservoir through the air inlet channel, the gas in the gas storage reservoir is compressed, its density increases, and the temperature rises significantly. Taking compressed air as an example, it is estimated that when the pressure of compressed air at 40°C is increased from 12 Mpa to 18 Mpa, the temperature rises to 85°C. The temperature fluctuation of the compressed gas greatly reduces the mass of compressed air that can be stored in the gas storage reservoir of the same volume, reduces the energy storage capacity of the system, and increases the energy storage cost. At the same time, the heat energy of the compressed air is directly dissipated to the outside and cannot be collected and utilized, affecting the overall efficiency of the system. When the gas storage reservoir discharges gas, the gas in the gas storage reservoir expands and absorbs heat, resulting in a sharp drop in temperature, affecting the normal operation of each component of the system and being unfavorable for the long-term stable operation of the system.

[0005] At present, various gas storage reservoirs all have the problem of temperature fluctuation caused by pressure fluctuation, resulting in high gas storage costs and difficulty in large-scale popularization. Therefore, how to control the temperature fluctuation of the gas storage reservoir and make full use of waste heat has become a prominent problem in the popularization and application of compressed air energy storage. At present, there is little research on the above problems and no specific solutions. Summary of the Invention

[0006] In view of the above problems, the present invention provides an energy storage system and a method for regulating the temperature of heat storage in the energy storage system. The energy storage system can control the temperature of the gas medium in the gas storage reservoir, making the charging and discharging temperatures in the gas storage reservoir tend to be stable, and increasing the amount of gas that can be compressed and stored in the gas storage reservoir.

[0007] In the technical solution of the present invention, an energy storage system is provided, which includes a gas storage reservoir, a gas compression device, and a gas expansion device; the gas storage reservoir is coupled with a first heat storage device, at least a part of the first heat storage device is arranged inside the gas storage reservoir, and the first heat storage device exchanges heat with the gas medium inside the gas storage reservoir; the gas compression device is connected to the air inlet of the gas storage reservoir; the gas expansion device is connected to the air outlet of the gas storage reservoir; when the gas medium enters the gas storage reservoir, the gas medium inside the gas storage reservoir exchanges heat with the first heat storage device, causing the temperature of the gas medium to drop; when the gas medium is discharged from the gas storage reservoir, the gas medium inside the gas storage reservoir exchanges heat with the first heat storage device, causing the temperature of the gas medium to rise.

[0008] According to the technical solution of the present invention, the gas compression device compresses the gas medium and inputs it into the air inlet of the gas storage reservoir. During the compression process, the gas medium increases in pressure and temperature; while the gas medium inside the gas storage reservoir is being compressed, the first heat storage device coupled to the gas storage reservoir exchanges heat with the gas medium entering the inside of the gas storage reservoir, cools the gas medium therein, and stores the absorbed heat; the gas storage reservoir stores the gas medium at high temperature and low pressure. The gas medium enters the gas expansion device from the air outlet of the gas storage reservoir for expansion. When the gas medium flows out of the gas storage reservoir, it exchanges heat with the first heat storage device, and the first heat storage device heats the gas medium with the stored heat. In the above energy storage system, the gas medium inside the gas storage reservoir is cooled, so that the mass of gas that can be accommodated per unit volume under the same pressure increases, thereby increasing the gas medium capacity of the gas storage reservoir without increasing the volume of the gas storage reservoir; when the gas medium flows out of the inside of the gas storage reservoir, it is heated to avoid the rapid cooling of the gas due to subsequent expansion and heat absorption, resulting in a drastic change in the temperature of the air outlet of the gas storage reservoir and its connection position, which affects the normal operation of the air outlet of the gas storage reservoir and its connected equipment. The first heat storage device coupled to the gas storage reservoir stores and utilizes the internal energy generated by the increase in the pressure of the gas storage reservoir caused by the entry of the gas medium, resulting in an increase in the temperature of the gas medium, reducing the temperature fluctuation of the gas medium in the gas storage reservoir, and eliminating the need for additional devices for compression cooling and expansion heating.

[0009] In the technical solution of the present invention, the energy storage system further includes a second heat storage device. The gas compression device is connected to the air inlet of the gas storage reservoir through the second heat storage device, and the gas expansion device is connected to the air inlet of the gas storage reservoir through the second heat storage device.

[0010] According to the technical solution of the present invention, the high-temperature and high-pressure gas medium compressed by the gas compression device first passes through the second heat storage device for cooling and then enters the gas storage reservoir; the second heat storage device also stores the absorbed heat; before the gas medium enters the gas expansion device from the outlet of the gas storage reservoir, it first passes through the second heat storage device, and the second heat storage device heats up the gas medium by the stored heat. The second heat storage device pre-treats the gas medium before compression and before expansion by cooling / heating, and cooperates with the first heat storage device that cools / heats the gas medium inside the gas storage reservoir, further achieving the goals of reducing the inlet temperature of the gas storage reservoir, increasing the outlet temperature of the gas storage reservoir, and improving the quality of the gas medium stored in the gas storage reservoir.

[0011] Preferably, in the technical solution of the present invention, the gas compression device includes multiple compressors connected in series, and / or the gas expansion device includes multiple turbines connected in series.

[0012] According to the technical solution of the present invention, multiple compressors connected in series for multi-stage compression can save compression power consumption and improve the cylinder volume utilization rate of the compressors; similarly, multiple turbines connected in series for multi-stage expansion can effectively increase expansion work, thereby improving the efficiency of the entire energy storage system.

[0013] Furthermore, in the technical solution of the present invention, the second heat storage device includes multiple heat storage units, and the heat storage units are arranged between multiple compressors / turbines connected in series.

[0014] According to the technical solution of the present invention, multiple heat storage units can perform multi-stage heat storage. The gas heated up by one compressor passes through one heat storage unit for cooling and then enters the next compressor / gas storage reservoir, thereby improving the heat storage efficiency and reducing the inlet temperature of the gas storage reservoir. Similarly, multiple heat storage units can perform multi-stage heating. The gas flowing out from the gas storage reservoir / one turbine passes through one heat storage unit for heating, thereby increasing the inlet temperature of the gas expansion system and improving the energy storage efficiency of the entire energy storage system.

[0015] Preferably, in the technical solution of the present invention, the first heat storage device includes a heat storage tank, heat exchange tubes, and a heat exchange pump. A heat storage medium is provided inside the heat storage tank; the heat exchange tubes pass through the heat storage tank and the gas storage reservoir, and the heat exchange medium in the heat exchange tubes exchanges heat with the media inside the heat storage tank and the gas storage reservoir respectively; the heat exchange pump is arranged on the heat exchange tubes to drive the flow of the heat exchange medium in the heat exchange tubes.

[0016] According to the technical solution of the present invention, the heat exchange medium circulates between the heat storage tank and the gas storage reservoir through the heat exchange tubes, for transferring the heat of the gas storage reservoir to the heat storage tank or transferring the heat of the heat storage tank to the gas storage reservoir.

[0017] Furthermore, in the technical solution of the present invention, the heat exchange tubes are bent and coiled inside the gas storage reservoir / heat storage tank, and the setting density of the heat exchange tubes at the inlet / outlet of the gas storage reservoir is greater than that at other positions of the gas storage reservoir.

[0018] According to the technical solution of the present invention, the heat exchange tubes are bent and coiled inside the gas storage reservoir / heat storage tank to increase the heat exchange area and heat exchange time between the heat exchange medium in the heat exchange tubes and the medium inside the gas storage reservoir / heat storage tank, and improve the heat exchange efficiency.

[0019] Preferably, in the technical solution of the present invention, the first heat storage device includes a plurality of spherical encapsulated heat storage units.

[0020] According to the technical solution of the present invention, the encapsulation of the spherical encapsulated heat storage unit can not only prevent the leakage of the heat storage medium and extend the service life, but also facilitate the installation of the unit and the implementation of the project; its spherical structure can reduce the stress generated by the heat storage medium inside during the heat absorption and heat release processes. Moreover, the accumulation of a large number of spherical encapsulated heat storage units can divide the gas medium flowing in the gas storage reservoir into small streams, enhance the fluid disturbance, effectively break through the surface boundary layer, and strengthen the heat exchange effect.

[0021] Preferably, in the technical solution of the present invention, the first heat storage device includes a plurality of heat storage rods arranged in a staggered arrangement to increase the heat exchange area and heat exchange time between the heat storage rods and the gas medium inside the gas storage reservoir, and improve the heat exchange efficiency.

[0022] Furthermore, in the technical solution of the present invention, the heat storage rod includes a column body, a heat storage medium, and a heat conduction medium. A plurality of fins extending in the axial direction are formed on the surface of the column body; the heat storage medium is arranged inside the column body; and the heat conduction medium covers the surface of the column body.

[0023] According to the technical solution of the present invention, the fins on the surface of the column body can increase the heat exchange area, and the heat conduction medium covering the surface of the column body can improve the heat exchange efficiency, thereby improving the overall heat exchange and heat storage efficiency of the heat storage rod.

[0024] In the technical solution of the present invention, a heat storage and temperature regulation method for an energy storage system is also provided. Applied to the above energy storage system, the heat storage and temperature regulation method includes: a heat storage step, when the gas medium enters the gas storage reservoir, the gas medium inside the gas storage reservoir exchanges heat with the first heat storage device, causing the temperature of the gas medium to drop; a heat release step, when the gas medium is discharged from the gas storage reservoir, the gas medium inside the gas storage reservoir exchanges heat with the first heat storage device, causing the temperature of the gas medium to rise. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic diagram of an energy storage system provided in the first embodiment of the present invention.

[0026] Figure 2It is a schematic diagram of a preferred energy storage system provided in the first embodiment of the present invention.

[0027] Figure 3 It is a schematic diagram of another preferred energy storage system provided in the first embodiment of the present invention.

[0028] Figure 4 It is a flowchart of a heat storage and temperature regulation method for an energy storage system provided in the embodiment of the present invention.

[0029] Figure 5 It is a schematic diagram of a gas storage reservoir provided in the second embodiment of the present invention.

[0030] Figure 6 It is a schematic diagram of a gas storage reservoir provided in the third embodiment of the present invention.

[0031] Figure 7 It is a schematic diagram of a gas storage reservoir provided in the fourth embodiment of the present invention.

[0032] Figure 8 It is a cross-sectional view of a heat storage rod provided in the fourth embodiment of the present invention.

[0033] Explanation of reference numerals: 100 - energy storage system, 1 - gas compression device, 11 - compressor, 2 - gas expansion device, 21 - turbine, 3 - gas storage reservoir, 30 - main body, 31 - air inlet, 32 - air outlet, 4 - first heat storage device, 41 - heat storage tank, 42 - heat exchange tube, 43 - heat exchange pump, 44 - spherical encapsulated heat storage unit, 45 - heat storage rod, 451 - cylinder, 452 - fin, 5 - second heat storage device, 51 - heat storage unit. Detailed Embodiments

[0034] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0035]

First Embodiment

[0036] Figure 1 It is a schematic diagram of a preferred energy storage system provided in the first embodiment of the present invention.

[0037] As Figure 1As shown, in the first embodiment of the present invention, an energy storage system 100 is provided, which is generally applied to a power system and can convert electrical energy into the potential energy of a gas medium and store it, and then convert the potential energy of the air into electrical energy and deliver it to the power system when needed.

[0038] The energy storage system 100 includes a gas compression device 1, a gas expansion device 2, and a gas storage tank 3. The gas compression device 1 is used to compress the gas medium, and the gas compression device 1 is connected to the inlet of the gas storage tank 3; the gas medium is pressurized and heated in the gas compression device 1, converting external energy such as electrical energy into the potential energy of the gas medium. The gas expansion device 2 is used to expand the gas medium, and the gas expansion device 2 is connected to the outlet of the gas storage tank 3; the gas medium is depressurized and cooled in the gas expansion device 2, converting the potential energy of the gas medium into external energy such as electrical energy.

[0039] The gas storage tank 3 is used to store the high-pressure gas medium. The gas storage tank 3 is coupled with a first heat storage device 4, and at least a part of the first heat storage device 4 is arranged inside the gas storage tank 3. The first heat storage device 4 exchanges heat with the gas medium inside the gas storage tank 3. In other words, the gas medium exchanges heat with the first heat storage device 4 while entering and leaving the gas storage tank 3. The first heat storage device 4 is used to store the waste heat generated during the compression process of the gas medium inside the gas storage tank 3 and the compression heat generated when entering the gas storage tank, and release the heat during the expansion stage to supplement heat to the gas medium.

[0040] In the first embodiment of the present invention, in the charging condition of the energy storage system 100, the external gas medium enters the gas compression device 1, and the gas compression device 1 compresses it to obtain a high-temperature and high-pressure gas medium and transports it into the gas storage tank 3 for storage. The first heat storage device 4 coupled in the gas storage tank 3 exchanges heat with the gas medium entering the inside of the gas storage tank 3 while the gas medium inside the gas storage tank 3 is being compressed, cools all the gas medium inside the gas storage tank 3, causing the temperature of the gas medium to drop. At the same time, the first heat storage device 4 stores the absorbed heat; in the charging condition of the gas storage tank 3, the heat generated by the compression of the gas medium is collected and stored by the first heat storage device 4 coupled to the gas storage tank 3, and the temperature rise amplitude during the compression of the gas medium can be controlled.

[0041] In the discharging condition of the energy storage system 100, the high-pressure gas medium stored in the gas storage tank 3 flows into the gas expansion device 2, and the gas expansion device 2 expands the gas medium and transports it to external equipment. While the gas medium flows out of the gas storage tank 3, the first heat storage device 4 coupled in the gas storage tank 3 exchanges heat with the gas medium in the gas storage tank 3, and the first heat storage device 4 uses the heat stored in the charging condition to heat the gas medium; the temperature drop amplitude during the expansion of the gas medium can be controlled.

[0042] In the above energy storage system 100, while the gas medium is compressed into the gas storage chamber 3, all the gas medium inside the gas storage chamber 3 is cooled, which can reduce the real-time temperature during the storage process of the gas medium, so that the amount of gas medium that can be accommodated per unit volume under the same pressure increases. Thus, without increasing the volume of the gas storage chamber, the amount of gas medium that the gas storage chamber 3 can accommodate is increased. And when the gas medium flows out of the inside of the gas storage chamber 3, it is heated to avoid the rapid cooling of the gas medium due to subsequent expansion and heat absorption, which may cause a drastic change in the temperature of the gas outlet of the gas storage chamber 3 and its connection position, affecting the normal operation of the gas outlet of the gas storage chamber 3 and its connected equipment. The first heat storage device 4 coupled to the gas storage chamber 3 stores and utilizes the heat generated during the compression process of the gas medium to stably regulate the temperature of the gas medium in the heat storage chamber 4, eliminating the need to additionally set up devices for compression cooling and expansion heating.

[0043] Figure 2 It is a schematic diagram of a preferred energy storage system provided in the first embodiment of the present invention.

[0044] As Figure 2 shown, in the first embodiment of the present invention, a preferred energy storage system 100 is provided. The energy storage system 100 further includes a second heat storage device 5. The gas compression device 1 is connected to the inlet of the gas storage chamber 3 through the second heat storage device 5, and the gas expansion device 2 is connected to the inlet of the gas storage chamber 3 through the second heat storage device 5.

[0045] In the first embodiment of the present invention, the high-temperature and high-pressure gas medium compressed by the gas compression device 1 first passes through the second heat storage device 5 for cooling and then enters the gas storage chamber 3; the second heat storage device 5 also stores the absorbed heat; before the gas medium enters the gas expansion device 2 from the outlet of the gas storage chamber 3, it first passes through the second heat storage device 5, and the second heat storage device 5 heats the gas medium by the stored heat. The second heat storage device 5 performs pre-cooling / heating treatment on the gas medium after compression and before expansion, and cooperates with the first heat storage device 4 that cools / heats the gas medium inside the gas storage chamber 3 to further reduce the inlet temperature of the gas storage chamber 3, increase the outlet temperature of the gas storage chamber 3, and increase the amount of gas medium stored in the gas storage chamber 3.

[0046] Figure 3 It is a schematic diagram of a preferred energy storage system provided in the first embodiment of the present invention.

[0047] As Figure 3As shown, in the first embodiment of the present invention, the gas compression device 1 includes multiple compressors 11 connected in series, and the gas expansion device 2 includes multiple turbines 21 connected in series; in other embodiments of the present invention, the gas compression device 1 and the gas expansion device 2 can be implemented as one or more combinations of other devices or apparatuses capable of performing gas compression / expansion, which are not limited herein.

[0048] Multiple compressors 11 connected in series perform multi-stage compression, which can save compression power consumption and improve the cylinder volume utilization rate of the compressors 11; similarly, multiple turbines 21 connected in series perform multi-stage expansion, which can effectively increase the expansion work done, thereby improving the efficiency of the entire energy storage system 100.

[0049] The second heat storage device 5 includes multiple heat storage units 51, and the heat storage units 51 are arranged between multiple compressors 11 / turbines 21 connected in series. Preferably, the number of heat storage units 51 is the same as the number of compressors 11 and the number of turbines 21.

[0050] In the first embodiment of the present invention, in the charging condition of the energy storage system 100, the external gas medium enters the first compressor 11 ( Figure 3 from left to right), is compressed, then enters the first heat storage unit 51 for cooling and heat storage, and then enters the second compressor 11 for compression; and so on until the gas medium enters the last compressor 11 for compression, then enters the last heat storage unit 51 for cooling and heat storage, and then flows into the gas storage tank 3. Thus, multiple heat storage units 51 can perform multi-stage heat storage, which can improve the heat storage efficiency and effectively reduce the inlet temperature of the gas storage tank 3.

[0051] Similarly, in the discharging condition of the energy storage system 100, the gas medium in the gas storage tank 3 enters the first heat storage unit 51 ( Figure 3 from right to left), is heated, then enters the first turbine 21 for expansion, and then enters the second heat storage unit 51 for heating; and so on until it enters the last compressor 11 for heat storage in the heat storage unit 51, and then expands through the last turbine 21, and the gas medium flows out of the energy storage system 100. Thus, multiple heat storage units 51 perform multi-stage heat release, which can increase the inlet temperature of the gas expansion system 2 and improve the energy storage efficiency of the overall energy storage system 100.

[0052] Figure 4 is a flowchart of a heat storage temperature regulation method for an energy storage system provided in the first embodiment of the present invention.

[0053] As Figure 4As shown in the figure, in the first embodiment of the present invention, a method for heat storage and temperature regulation of an energy storage system 100 is further provided, which is applied to the above-mentioned energy storage system 100. The method for heat storage and temperature regulation includes: a heat storage step S1. When the gas medium enters the gas storage chamber, all the gas medium in the gas storage chamber exchanges heat with the first heat storage device, causing the temperature of the gas medium to drop; a heat release step SS2. When the gas medium is discharged from the gas storage chamber, the gas medium in the gas storage chamber exchanges heat with the first heat storage device, causing the temperature of the gas medium to rise.

[0054]

Second Embodiment

[0055] Figure 5 It is a schematic diagram of a gas storage chamber provided in the second embodiment of the present invention.

[0056] As Figure 5 shown in the figure, in the second embodiment of the present invention, the gas storage chamber 3 includes a main body portion 30, an air inlet 31, and an air outlet 32. The air inlet 31 is used to introduce a gas medium into the main body portion 30, and the air outlet 32 is used to lead the gas medium out of the main body portion 30.

[0057] In this embodiment, the first heat storage device 4 includes a heat storage tank 41, a heat exchange tube 42, and a heat exchange pump 43. A heat storage medium is provided inside the heat storage tank 41 for storing / releasing heat; the heat exchange tube passes through the heat storage tank 41 and the main body portion 30 of the gas storage chamber 3. The heat exchange medium in the heat exchange tube 42 serves as an intermediary for heat transfer and circulates between the heat storage tank 41 and the gas storage chamber 3, exchanging heat with the heat storage medium in the heat storage tank 41 and the gas medium inside the gas storage chamber 3 respectively; the heat exchange pump 43 is provided on the heat exchange tube 42 to drive the heat exchange medium in the heat exchange tube 42 to flow. Among them, the heat exchange medium can adopt a liquid with a relatively large thermal conductivity such as heat-conducting oil, deionized water, or nanofluid, which is not limited herein.

[0058] In the second embodiment of the present invention, under the gas charging condition, the heat exchange medium in the heat exchange tube 42 exchanges heat with the high-temperature and high-pressure gas medium in the gas storage chamber 3, the gas medium cools down while the heat exchange medium warms up; the heat exchange medium that absorbs heat and warms up in the heat exchange tube 42 flows to the heat storage tank 41, and the heat storage medium in the heat storage tank 41 absorbs and stores the heat of the heat exchange medium in the heat exchange tube 42, the heat exchange medium cools down while the heat storage medium warms up; the cooled heat exchange medium circulates back to the gas storage chamber 3 through the heat exchange tube 42 again and exchanges heat with the high-temperature and high-pressure gas medium in the gas storage chamber 3, reducing the inlet temperature of the gas storage chamber 3. Under the gas charging condition, the heat exchange medium absorbs the heat of the gas medium in the gas storage chamber 3 and stores it in the heat storage medium in the heat storage tank 41.

[0059] When the energy storage system 100 is in the deflation condition, the heat exchange medium in the heat exchange tube 42 exchanges heat with the high-temperature heat storage medium in the heat storage tank 41. The heat storage medium releases heat and cools down while the heat exchange medium heats up. The heat exchange medium that absorbs heat and heats up in the heat exchange tube 42 flows to the gas storage reservoir 3. The heat exchange medium cools down, causing the gas medium in the gas storage reservoir 3 to heat up. The cooled heat exchange medium circulates back to the heat storage tank 41 through the heat exchange tube 42 again. The heat storage tank 41 continues to release heat to heat up the heat exchange medium again. The heated heat exchange medium circulates back to the gas storage reservoir 3 through the heat exchange tube 42 again to exchange heat with the gas medium in the gas storage reservoir 3, increasing the outlet temperature of the gas storage reservoir 3. When in the inflation condition, the heat exchange medium releases the heat stored by the heat storage medium in the heat storage tank 41, increasing the outlet temperature of the gas storage reservoir 3.

[0060] Preferably, in the second embodiment of the present invention, the heat exchange tube 42 is zigzag bent and coiled in the gas storage reservoir 3 / heat storage tank 41 to increase the heat exchange area and heat exchange time between the heat exchange medium in the heat exchange tube 42 and the medium inside the gas storage reservoir 3 / heat storage tank 41, improving the heat exchange efficiency.

[0061] The setting density of the heat exchange tube 42 at the inlet 31 / outlet 32 of the gas storage reservoir 3 is greater than that at other positions in the gas storage reservoir 3. The gas medium flow rate is relatively fast at the inlet 31 / outlet 32. Therefore, the part of the heat exchange tube 42 close to the inlet 31 / outlet 32 is relatively dense, which can strengthen the air flow disturbance and improve the heat exchange efficiency.

[0062]

Third Embodiment

[0063] Figure 6 It is a schematic diagram of a gas storage reservoir provided in the third embodiment of the present invention.

[0064] As Figure 6 shown, in the third embodiment of the present invention, the first heat storage device 4 includes a plurality of spherical encapsulated heat storage units 44. The spherical encapsulated heat storage units 44 are arranged in the main body 30 of the gas storage reservoir 3, and a heat storage medium is encapsulated inside the spherical encapsulated heat storage units 44.

[0065] The encapsulation of the spherical encapsulated heat storage unit 44 can not only prevent the leakage of the heat storage medium and extend its lifespan, but also facilitate unit installation and project implementation. Its spherical structure can reduce the stress generated by the internal heat storage medium during the heat absorption and heat release processes. Moreover, the accumulation of a large number of spherical encapsulated heat storage units 44 can divide the gas medium flowing in the gas storage reservoir 3 into small streams, enhancing the fluid disturbance, effectively breaking through the surface boundary layer, and strengthening the heat exchange effect.

[0066]

Fourth Embodiment

[0067] Figure 7 It is a schematic diagram of a gas storage reservoir provided in the fourth embodiment of the present invention.

[0068] As Figure 7 shown, in the fourth embodiment of the present invention, the first heat storage device 4 includes a plurality of heat storage rods 45 arranged in a staggered pattern. Both ends of the heat storage rod 45 are connected and fixed to the inner wall of the main body 30 of the gas storage chamber 3. The structure arranged in a staggered pattern can enhance the air flow disturbance, increase the heat exchange area and heat exchange time between the heat storage rod 45 and the gas medium inside the gas storage chamber 3, and improve the heat exchange efficiency.

[0069] Figure 8 Fig. is a cross-sectional view of a heat storage rod provided in the fourth embodiment of the present invention.

[0070] As Figure 8 shown, in this embodiment, the heat storage rod 45 includes a cylinder 451, a heat storage medium, and a heat conduction medium. A plurality of fins 452 extending in the axial direction are formed on the surface of the cylinder 451; the heat storage medium is arranged inside the cylinder 451; and the heat conduction medium covers the surface of the cylinder 451.

[0071] In this embodiment, the fins 452 on the surface of the cylinder 451 can increase the heat exchange area, and the heat conduction medium covering the surface of the cylinder 451 can improve the heat exchange efficiency, thereby improving the overall heat exchange and heat storage efficiency of the heat storage rod.

[0072] Preferably, in all embodiments of the present invention, the heat storage medium can be a phase change material or a non-phase change material with a specific heat capacity greater than 0.8 kJ / (kg·K), including but not limited to paraffin, sodium nitrate, lauric acid, etc.; the heat conduction medium can be a porous medium, a polymer, or an alloy, including but not limited to expanded graphite, molecular sieve, zeolite, etc.

[0073] In the practical application of the present invention, the first heat storage device 4 can also be set as other types of heat storage devices, or a combination of one or more forms in the above embodiments, which is not limited herein.

[0074] So far, the technical solutions of the present invention have been described in conjunction with the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to the above specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. An energy storage system, characterized in that: include: A gas storage reservoir, wherein the gas storage reservoir is coupled to a first heat storage device, at least a portion of the first heat storage device is disposed inside the gas storage reservoir, and the first heat storage device performs heat exchange with a gas medium inside the gas storage reservoir; A gas compression device connected to the gas inlet of the gas storage reservoir; A gas expansion device connected to the gas outlet of the gas storage reservoir; When the gas medium enters the gas storage reservoir, the gas medium in the gas storage reservoir exchanges heat with the first heat storage device, so that the temperature of the gas medium decreases; when the gas medium is discharged from the gas storage reservoir, the gas medium in the gas storage reservoir exchanges heat with the first heat storage device, so that the temperature of the gas medium increases.

2. The energy storage system according to claim 1, characterized in that: It also includes a second heat storage device, the gas compression device is connected to the air inlet of the gas storage reservoir through the second heat storage device, and the gas expansion device is connected to the air inlet of the gas storage reservoir through the second heat storage device.

3. The energy storage system according to claim 2, characterized in that: The gas compression device comprises a plurality of compressors connected in series, and / or the gas expansion device comprises a plurality of turbines connected in series.

4. The energy storage system according to claim 3, characterized in that: The second heat storage device includes a plurality of heat storage units, and the heat storage units are arranged between a plurality of the compressors / turbines connected in series.

5. The energy storage system according to claim 1, characterized in that: The first heat storage device comprises: A heat storage tank, wherein a heat storage medium is arranged inside; A heat exchange pipe passes through the heat storage tank and the gas storage reservoir, and the heat exchange medium in the heat exchange pipe exchanges heat with the medium inside the heat storage tank and the gas storage reservoir respectively; The heat exchange pump is arranged on the heat exchange tube to drive the heat exchange medium in the heat exchange tube to flow.

6. The energy storage system according to claim 5, characterized in that: The heat exchange tubes are bent and coiled in the gas storage reservoir / the heat storage tank, and the arrangement density of the heat exchange tubes at the air inlet / air outlet of the gas storage reservoir is greater than the arrangement density of the heat exchange tubes at other positions of the gas storage reservoir.

7. The energy storage system according to claim 1, characterized in that: The first heat storage device includes a plurality of spherical packaged heat storage units.

8. The energy storage system according to claim 1, characterized in that: The first heat storage device includes a plurality of heat storage rods arranged in a staggered manner.

9. The energy storage system according to claim 8, characterized in that: The heat storage rod comprises a column, and a plurality of fins extending in the axial direction are formed on the surface of the column; A heat storage medium is arranged inside the column; A heat-conducting medium covers the surface of the column.

10. A heat storage temperature control method for an energy storage system, applied to the energy storage system according to any one of claims 1 to 9, characterized in that: The heat storage temperature regulation method comprises: a heat storage step, when the gas medium enters the gas storage, the gas medium in the gas storage performs heat exchange with the first heat storage device, so that the temperature of the gas medium decreases; In the heat release step, when the gas medium is discharged from the gas storage, the gas medium in the gas storage exchanges heat with the first heat storage device, so that the temperature of the gas medium increases.

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