A gigawatt-hour-level liquid flow battery storage tank body and a liquid flow battery energy storage system

Abstract

The application relates to the technical field of liquid flow battery energy storage, in particular to a gigawatt-hour-level liquid flow battery liquid storage tank body and a liquid flow battery energy storage system, which comprises a pressure-bearing tank body, a liquid storage cavity is formed in the pressure-bearing tank body; a protection structure comprises at least one impermeable layer and at least one detection layer, the detection layer is arranged on the inner wall of the liquid storage cavity and is used for monitoring whether the impermeable layer leaks, and the impermeable layer is arranged on the inner side of the detection layer and is used for being in contact with electrolyte; a bubbling device is arranged in the liquid storage cavity, and the bubbling device is used for conveying inert gas into the liquid storage cavity to disturb and mix the electrolyte. The application can simultaneously meet the requirements of large-scale electrolyte centralized storage and uniform thermal management.

Description

Technical Field

[0001] This application relates to the technical field of flow battery energy storage, and in particular to a gigawatt-hour flow battery liquid storage tank and a flow battery energy storage system. Background Technology

[0002] Currently, vanadium redox flow batteries are widely recognized as a key technology in large-scale, long-term energy storage due to their inherent advantages such as high safety, ultra-long cycle life, and the ability to independently design power and capacity. As the global energy structure shifts towards a renewable energy-dominated model, the demand for energy storage systems is rapidly expanding from megawatt-hours (MWh) to gigawatt-hours (GWh), and even higher. This exponential growth in energy storage capacity has directly led to a surge in the storage capacity of electrolytes, the energy storage medium, from thousands of cubic meters to tens or even hundreds of thousands of cubic meters.

[0003] In related technologies, MWh-level flow battery systems mostly use traditional single or small array-type plastic or fiberglass tanks, which have limited liquid storage capacity per tank, with a maximum of only tens of cubic meters. When facing the storage requirements of hundreds of thousands of cubic meters at the GWh level, only a modular tank array solution can be adopted, that is, a large number of small tanks are arranged in an array and connected to the stack system through pipelines. However, this modular tank array solution has significant limitations in GWh-level application scenarios: on the one hand, the arrangement of a large number of small tanks results in a huge footprint, and the connecting pipelines between the tanks are complex, which dramatically increases the construction cost and maintenance difficulty of the system; on the other hand, if a large civil engineering liquid storage tank is used to replace the small tank array to reduce the footprint, the traditional built-in immersion thermal management method (such as setting up a coil cooler inside the liquid storage tank) faces serious problems. Due to the extremely low thermal conductivity of corrosion-resistant plastic materials, the heat exchange efficiency is difficult to meet the heat exchange requirements of GWh-level massive electrolytes, and the lack of effective stirring means in large liquid storage tanks leads to serious uneven distribution of electrolyte temperature and concentration inside the tank, affecting the operating efficiency and service life of the battery system.

[0004] Furthermore, large-scale civil engineering liquid storage tanks face severe challenges in preventing seepage and corrosion when storing highly acidic electrolytes for extended periods. Due to the enormous size of these tanks, with inner wall areas reaching thousands of square meters, any localized damage to the impermeable layer that goes undetected will not only result in the loss of expensive electrolytes and pollution of the surrounding soil and groundwater, but also make it extremely difficult to pinpoint leaks on such a large area of ​​the inner wall, leading to high repair costs.

[0005] Therefore, there is a problem that it is difficult to simultaneously meet the comprehensive requirements of large-scale centralized electrolyte storage, efficient and uniform thermal management, and reliable anti-seepage and anti-corrosion monitoring. There is an urgent need for a gigawatt-hour-level flow battery storage tank and flow battery energy storage system. Summary of the Invention

[0006] To simultaneously meet the requirements of large-scale centralized electrolyte storage, uniform thermal management, and reliable anti-seepage and anti-corrosion monitoring, this application provides a gigawatt-hour-level flow battery electrolyte storage tank and a flow battery energy storage system.

[0007] In a first aspect, the gigawatt-hour-level flow battery storage tank provided in this application adopts the following technical solution:

[0008] A gigawatt-hour flow battery liquid storage tank includes:

[0009] A pressure tank body, wherein a liquid storage chamber is formed inside the pressure tank body;

[0010] The protective structure includes at least one impermeable layer and at least one detection layer. The detection layer is disposed on the inner wall of the liquid storage cavity and is used to monitor whether the impermeable layer leaks. The impermeable layer is disposed on the inner side of the detection layer and is used to contact the electrolyte.

[0011] A bubbling device is disposed in the liquid storage chamber. The bubbling device is used to deliver inert gas into the liquid storage chamber to turbulently mix the electrolyte.

[0012] By adopting the above technical solutions, the pressure tank provides a large-volume storage chamber for storing the large amount of electrolyte required for gigawatt-hour flow batteries. The protective structure adopts a composite design of a detection layer and a seepage-proof layer. The seepage-proof layer is in direct contact with the electrolyte and plays a role in corrosion prevention and seepage prevention. The detection layer is set between the seepage-proof layer and the inner wall of the storage chamber, which can monitor whether the seepage-proof layer is leaking, facilitating the early detection of leakage. The bubbling device generates bubbles by introducing inert gas into the storage chamber. During the rise of the bubbles, they turbulently mix the electrolyte, which helps to reduce the concentration stratification and temperature unevenness of the electrolyte in the large-volume storage chamber. At the same time, the inert gas can also protect the electrolyte and inhibit oxidation, thus helping to meet the requirements of large-scale centralized storage of electrolyte and uniform thermal management.

[0013] Optionally, the detection layer includes a detection unit and multiple insulation blocks. The multiple insulation blocks are sequentially spliced ​​and laid on the inner wall of the liquid storage chamber. The detection unit is embedded between the multiple insulation blocks and is used to monitor whether the seepage prevention layer leaks.

[0014] By adopting the above technical solution, the detection layer is constructed by splicing and laying insulation blocks. The insulation blocks not only serve as the structural matrix of the detection layer, but also provide thermal insulation for the liquid storage chamber, reducing heat exchange between the electrolyte and the external environment, which is conducive to maintaining the stability of the electrolyte temperature. The detection unit is embedded between the insulation blocks, and the monitoring elements are arranged by utilizing the splicing gap between the insulation blocks. The structure is compact and does not occupy the effective volume of the liquid storage chamber.

[0015] Optionally, the detection unit includes multiple guide channels laid between the insulation blocks. The multiple guide channels are crisscrossed to form a grid-like guide channel, and a leakage detector is provided at the intersection of the multiple guide channels.

[0016] By adopting the above technical solution, the crisscrossing guide channels form a grid-like guiding channel. When local leakage occurs in the seepage prevention layer, the leaked electrolyte will flow along the guide channels and be guided to the intersection. The leakage detectors set at the intersection can detect the presence of the leaked liquid in time, thereby achieving accurate location and early warning of leakage. The grid-like layout allows the guide channels to cover all areas of the inner wall of the liquid storage cavity, improving the comprehensiveness and sensitivity of leakage detection.

[0017] Optionally, the protective structure further includes a leak-proof structural layer, which is disposed between the detection layer and the seepage-proof layer. The leak-proof structural layer is made of spliced ​​metal plates, and the splice seams between the metal plates are aligned with the flow channel.

[0018] By adopting the above technical solution, a leak-proof structural layer is added between the detection layer and the seepage-proof layer, forming a three-layer protection system consisting of the seepage-proof layer, the leak-proof structural layer, and the detection layer, further improving the reliability of corrosion and seepage prevention. The leak-proof structural layer is made of spliced ​​metal plates, which have good corrosion resistance and mechanical strength, and can serve as structural support for the seepage-proof layer. The splicing seams between the metal plates are the weakest points most likely to leak. The splicing seams are aligned with the diversion channels, so that once electrolyte seeps from the splicing seams, it can be quickly collected by the corresponding diversion channels and guided to the leak detector, greatly improving the targeting and response speed of leak detection.

[0019] Optionally, the bubbling device includes a gas distribution network laid along the bottom of the liquid storage chamber, and the gas distribution network has a plurality of bubbling holes facing upwards towards the liquid storage chamber.

[0020] By adopting the above technical solution, the gas distribution network is laid along the bottom of the liquid storage chamber, and the bubbling holes face upwards of the liquid storage chamber. After the inert gas is released from the bubbling holes at the bottom, it forms bubbles. Under the action of buoyancy, the bubbles rise from the bottom to the liquid surface. During the rising process, they drive the surrounding electrolyte to move, forming a bottom-up turbulence effect, which can effectively stir the electrolyte in the entire liquid storage chamber and achieve uniform mixing throughout the entire chamber.

[0021] Optionally, the gas distribution network includes at least two concentric annular gas distribution pipes, adjacent annular gas distribution pipes are connected to each other by a connecting pipe, and the bubbling holes are formed on the annular gas distribution pipes.

[0022] By adopting the above technical solution, the gas distribution network adopts a concentric ring gas distribution pipe structure. The concentric arrangement of multiple ring gas distribution pipes can make the bubbling holes more evenly distributed in the radial direction at the bottom of the liquid storage chamber, which is conducive to the more even release of bubbles on the bottom cross section and reduces the area of ​​insufficient local agitation. Adjacent ring gas distribution pipes are connected to each other through connecting pipes, so that the gas pressure between each ring gas distribution pipe tends to be balanced, which is conducive to the consistent gas output of each bubbling hole.

[0023] Optionally, a gas phase space is formed at the top of the liquid storage chamber. A protective gas tube assembly and a hydrogen concentration detector are installed in the gas phase space. An interlocking control valve is installed on the protective gas tube assembly. The interlocking control valve is signal-connected to the hydrogen concentration detector. When the hydrogen concentration detector detects that the hydrogen concentration in the gas phase space reaches a preset threshold, the interlocking control valve opens to purge the gas phase space through the protective gas tube assembly.

[0024] By adopting the above technical solution, a protective gas tube assembly and a hydrogen concentration detector are installed in the gas phase space at the top of the liquid storage chamber, and the signals of the two are linked through a linkage control valve. During the charging and discharging process of the flow battery, the electrolyte may produce a small amount of hydrogen gas due to side reactions and accumulate in the gas phase space. When the hydrogen concentration reaches a preset threshold, the linkage control valve automatically opens, and inert gas is introduced into the gas phase space through the protective gas tube assembly for scavenging and replacement, reducing the hydrogen concentration to below a safe range. This effectively prevents the safety hazards caused by hydrogen accumulation and realizes automated safety management of the gas phase space.

[0025] Optionally, the liquid storage chamber is provided with an inlet pipe and an outlet pipe. The inlet pipe enters from the top of the pressure tank and extends to the top of the liquid storage chamber. The inlet pipe is distributed in the area near the side wall of the pressure tank. The outlet pipe is located at the bottom of the liquid storage chamber and is distributed in the central area of ​​the liquid storage chamber. The port of the outlet pipe near the bottom of the liquid storage chamber is flared, and a filter element is provided at the port.

[0026] By adopting the above technical solution, the inlet pipe enters from the top of the pressure tank and is distributed in the area near the side wall, while the outlet pipe is located in the bottom center area. This layout, with the inlet at the upper outer ring and the outlet at the bottom center, allows the electrolyte to flow from the outer ring to the center and from the top to the bottom within the storage chamber, which is beneficial for the full mixing and uniform distribution of the electrolyte. The outlet pipe port is designed in a funnel shape, which increases the liquid absorption area, reduces the flow velocity at the port, and minimizes disturbance to the bottom sediment. The filter element installed at the port can filter impurity particles in the electrolyte, preventing impurities from entering the circulation pipeline and the fuel cell stack, thus protecting the system equipment.

[0027] Secondly, this application provides a flow battery energy storage system, which adopts the following technical solution:

[0028] A flow battery energy storage system, comprising:

[0029] At least two of the above-mentioned gigawatt-hour flow battery storage tanks, wherein at least one serves as a positive electrode electrolyte storage tank and at least one serves as a negative electrode electrolyte storage tank;

[0030] fuel cell stack clusters;

[0031] The fluid distribution module includes a distribution pipeline network and a circulation pump group connected to the distribution pipeline network, wherein the distribution pipeline network forms a circulation loop connecting the liquid storage tank and the fuel cell stack cluster;

[0032] A heat exchange device is installed outside the electrolyte storage tank of the gigawatt-hour flow battery. The heat exchange device includes a heat exchange unit, a bypass pipeline, and a bypass regulating valve. The heat exchange unit is connected in parallel to the distribution network through the bypass pipeline. The bypass regulating valve is installed on the bypass pipeline and is used to regulate the flow rate of the electrolyte flowing through the bypass pipeline.

[0033] By adopting the above technical solution, the heat exchange device is independently installed outside the storage tank, which helps to avoid the problem of low heat exchange efficiency caused by the heat exchange device being directly immersed in a large volume of electrolyte. The heat exchange unit is set up in parallel with a section of the main pipeline via a bypass pipeline. The electrolyte in the main pipeline is split at this parallel section, with part flowing through the heat exchange unit for heat exchange and part flowing directly through this section of the main pipeline. By adjusting the opening of the bypass regulating valve, the flow ratio of the heat exchange unit in the bypass pipeline can be controlled, thereby achieving the regulation of the circulating electrolyte temperature. When the opening of the bypass regulating valve increases, the flow resistance of the bypass pipeline decreases, and more electrolyte flows through the heat exchange unit for heat exchange; when the opening of the bypass regulating valve decreases, the flow resistance of the bypass pipeline increases, and more electrolyte flows directly through the main pipeline.

[0034] Optionally, the fuel cell stack cluster includes multiple individual fuel cell stacks, and the distribution network adopts a reverse parallel pipeline design. The distribution network includes a main pipeline and multiple branch pipelines, each of which is connected to the corresponding individual fuel cell stack, and the total pipeline length of each branch pipeline is equal.

[0035] By adopting the above technical solution, the distribution network adopts a reverse parallel pipeline design, which makes the total pipeline length of each branch equal, thereby ensuring that the electrolyte flow and fluid pressure drop distributed to each individual stack remain balanced. This avoids the concentration polarization problem caused by uneven electrolyte flow between stacks due to differences in pipeline length, and improves the overall charging and discharging consistency and efficiency of the stack cluster.

[0036] In summary, this application includes at least one of the following beneficial technical effects:

[0037] 1. By setting a protective structure including a detection layer and an anti-seepage layer on the inner wall of the liquid storage chamber of the pressure tank, and setting a bubbling device in the liquid storage chamber, the safe storage and uniform mixing of electrolyte in large liquid storage tanks are realized. The detection layer can monitor whether the anti-seepage layer leaks in real time, and the bubbling device prevents electrolyte stratification by inert gas turbulence. This solves the safety and uniformity problems of large-scale electrolyte storage in gigawatt-hour-level large-capacity flow battery energy storage systems.

[0038] 2. By combining the grid-like guide channel of the flow channel with the leakage detector at the intersection node, and the alignment design of the splice seam of the leak-proof structure layer with the flow channel, the precise location and detection of leakage can be achieved, improving the sensitivity and reliability of leakage detection.

[0039] 3. By independently setting the heat exchange device outside the liquid storage tank and adopting a design that connects the heat exchange unit and the bypass pipeline in parallel and then in series to the circulation loop, the heat exchange efficiency can be flexibly adjusted, while avoiding the excessive flow resistance and energy loss caused by forcing all the electrolyte through the heat exchanger. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the overall structure of a gigawatt-hour flow battery storage tank in an embodiment of this application.

[0041] Figure 2 This is a partial structural diagram of the detection layer in an embodiment of this application.

[0042] Figure 3 This is a schematic diagram of the gas distribution network in an embodiment of this application.

[0043] Figure 4 This is a schematic diagram of the structure of the protective airway assembly in the embodiments of this application.

[0044] Figure 5 This is a schematic diagram showing the distribution of the inlet and outlet pipes within the liquid storage chamber in an embodiment of this application.

[0045] Figure 6 This is a schematic diagram of the structure of the flow battery energy storage system in the embodiments of this application.

[0046] Figure 7 This is a schematic diagram of the connection structure between the fuel cell stack cluster and the fluid distribution module in an embodiment of this application.

[0047] Explanation of reference numerals in the attached figures:

[0048] 1. Pressure tank body; 11. Liquid storage chamber; 111. Gas phase space; 12. Ceiling structure; 121. Anti-corrosion sealing layer; 122. Thermal insulation layer; 13. Anti-settlement foundation; 14. Protective gas pipeline assembly; 141. Nitrogen input pipeline; 142. Forced exhaust pipeline; 15. Hydrogen concentration detector; 16. Interlocking control valve; 17. Temperature detection device; 18. Liquid inlet pipeline; 19. Liquid outlet pipeline; 191. Liquid outlet pipe support; 192. Filter element; 2. Protective structure; 21. Leak-proof layer; 22. Detection layer; 2 21. Detection unit; 2211. Flow channel; 2212. Leakage detector; 222. Insulation block; 23. Leak-proof structural layer; 3. Bubbling device; 31. Gas distribution network; 311. Annular gas distribution pipe; 312. Connecting pipe; 3121. Bubbling hole; 4. Fuel cell stack cluster; 41. Individual fuel cell stack; 5. Fluid distribution module; 51. Distribution network; 511. Main pipeline; 512. Branch pipeline; 52. Circulating pump set; 6. Heat exchange device; 61. Heat exchange unit; 62. Bypass pipeline; 63. Bypass regulating valve. Detailed Implementation

[0049] The following is in conjunction with the appendix Figure 1-7 This application will be described in further detail.

[0050] This application discloses a gigawatt-hour flow battery liquid storage tank.

[0051] It should be noted that, in the description of this invention, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0052] Reference Figure 1 A gigawatt-hour flow battery storage tank includes a pressure tank 1, a protective structure 2, and a bubbling device 3. The protective structure 2 and the bubbling device 3 are respectively disposed within the pressure tank 1.

[0053] The pressure tank 1 is a large civil engineering structure, constructed of acid-resistant reinforced concrete with added impermeable agents. An internal liquid storage chamber 11 is formed within the pressure tank 1. The pressure tank 1 is cylindrical, with a diameter of 20-50 meters and a height of 10-20 meters. The volume of a single liquid storage chamber 11 can reach several thousand to tens of thousands of cubic meters, meeting the electrolyte storage capacity requirements of gigawatt-hour-level flow battery energy storage systems.

[0054] The pressure tank 1 is supported by a steel frame dome, and the dome is covered with an acid-resistant reinforced concrete layer with an anti-permeability agent. A suspended ceiling structure 12 is located below the dome, comprising an anti-corrosion sealing layer 121 and an insulation layer 122. The anti-corrosion sealing layer 121 is composed of a high-molecular engineering plastic sheet resistant to strong acids and oxidation, and the insulation layer 122 is composed of a single or composite insulation material and is placed above the anti-corrosion sealing layer 121. The suspended ceiling structure 12 covers the interior of the tank, forming a sealed and insulated structure inside the tank. A gas phase space 111 is formed between the top of the liquid storage chamber 11 and the suspended ceiling structure 12.

[0055] The bottom of the pressure tank 1 is provided with an anti-settlement foundation 13. The anti-settlement foundation 13 is used to support the weight of the pressure tank 1 and the massive amount of electrolyte inside, and to prevent structural damage to the tank due to uneven settlement.

[0056] The bottom of the liquid storage chamber 11 is designed with a drainage slope of 0.3-0.6 degrees towards the center, so that the electrolyte can flow along the slope and collect to the lowest point in the center of the liquid storage chamber 11 during later maintenance and residual liquid recovery.

[0057] The protective structure 2 is installed on the inner wall of the liquid storage chamber 11. The protective structure 2 includes a seepage-proof layer 21, a detection layer 22, and a leak-proof structural layer 23. From the inner wall of the pressure tank 1 towards the center of the liquid storage chamber 11, the arrangement order of the layers of the protective structure 2 is as follows: detection layer 22, leak-proof structural layer 23, and seepage-proof layer 21. Among them, the detection layer 22 is installed on the inner wall of the liquid storage chamber 11, that is, the detection layer 22 is directly attached to the inner wall surface of the pressure tank 1.

[0058] Reference Figure 1 and Figure 2 The detection layer 22 includes a detection unit 221 and multiple insulation blocks 222. The insulation blocks 222 are sequentially spliced ​​and laid on the inner wall of the liquid storage chamber 11, covering the entire inner surface of the bottom and side walls of the liquid storage chamber 11. The insulation blocks 222 are made of corrosion-resistant closed-cell foamed material, such as closed-cell foamed polypropylene or closed-cell foamed polyethylene, and have good thermal insulation performance and chemical corrosion resistance. The thickness of the insulation blocks 222 is set according to the insulation requirements; in this embodiment, the thickness of the insulation blocks 222 is 50-100 mm.

[0059] The detection unit 221 is embedded between multiple insulation blocks 222. Specifically, the detection unit 221 includes multiple flow channels 2211 laid between the insulation blocks 222. The multiple flow channels 2211 are crisscrossed to form a grid-like guiding channel, and the flow channels 2211 are grooves formed on the splicing surfaces of adjacent insulation blocks 222. When adjacent insulation blocks 222 are spliced, the grooves on the two insulation blocks 222 fit together to form a complete flow channel 2211.

[0060] The cross-section of the flow guide channel 2211 is semi-circular or rectangular, with a width of 5-15 mm and a depth of 5-10 mm. Multiple flow guide channels 2211 form a crisscrossing grid pattern on the inner wall of the liquid storage chamber 11, with the grid spacing set according to the required detection accuracy. In this embodiment, the grid spacing is 500-1000 mm.

[0061] Leakage detectors 2212 are installed at the intersections of multiple flow channels 2211. The leakage detectors 2212 are either electrochemical sensors or resistive humidity sensors, capable of detecting the presence of liquid within the flow channels 2211. The leakage detectors 2212 are connected to an external monitoring system via signal cables. When a leakage detector 2212 detects liquid, the monitoring system can accurately locate the area of ​​leakage based on the coordinates of that leakage detector.

[0062] In another embodiment, the detection layer 22 can also be made of distributed optical fiber sensors laid on the inner wall of the liquid storage chamber 11. The distributed optical fiber sensors determine whether there is liquid leakage into the area where the detection layer 22 is located by detecting changes in the refractive index or light intensity of the optical fiber, thereby realizing the monitoring of the leakage status of the anti-seepage layer 21.

[0063] The leak-proof structural layer 23 is located inside the detection layer 22. The leak-proof structural layer 23 is made of high-performance acid-resistant stainless steel or other metal sheets welded together using high-energy beam welding to form a metal leak-proof lining. Specifically, the leak-proof structural layer 23 is made by laser welding or argon arc welding of the metal sheets, and the welds are inspected by radiographic testing. After welding, the weld area is passivated.

[0064] The welded joints between the metal sheets are aligned with the flow channels 2211, meaning each welded joint is aligned with one of the flow channels 2211 below it in the projection direction. Although the welded joints are welded, they are still relatively weak points compared to the base material area of ​​the metal sheet, posing a potential risk of leakage. Therefore, when electrolyte permeates from the impermeable layer 21 and further seeps out from the welded joints of the metal sheets, the leaked liquid falls directly into the corresponding flow channel 2211, flows along the flow channel 2211 to the intersection node where it is detected by the leak detector 2212, thus realizing the detection and location of the leak.

[0065] The impermeable layer 21 is a flexible impermeable main membrane layer, located inside the leak-proof structural layer 23. This flexible impermeable main membrane layer is in direct contact with the electrolyte in the storage chamber 11, serving as the innermost anti-corrosion interface directly in contact with the electrolyte. The flexible impermeable main membrane layer is made of acid- and strong-oxidizing high-molecular-weight engineering plastics, such as high-density polyethylene (HDPE) or polytetrafluoroethylene (PTFE) membranes, and is attached to the inner surface of the leak-proof structural layer 23, forming a continuous impermeable barrier. The thickness of the impermeable layer 21 is 1-3 mm.

[0066] In another embodiment, the protective structure 2 may include two impermeable layers 21 and two detection layers 22, with the two impermeable layers 21 and the two detection layers 22 being alternately arranged.

[0067] Reference Figure 1 and Figure 3 The bubbling device 3 is a tubular bubbling device, which is installed inside the liquid storage chamber 11. The bubbling device 3 includes a gas distribution network 31 laid along the bottom of the liquid storage chamber 11. The gas distribution network 31 is located at the bottom of the liquid storage chamber 11 and is immersed in the electrolyte.

[0068] The gas distribution network 31 includes at least two concentrically arranged annular gas distribution pipes 311. In this embodiment, the gas distribution network 31 includes two concentrically arranged annular gas distribution pipes 311, with the diameter of the annular gas distribution pipes 311 increasing sequentially from the inside to the outside, corresponding to the inner and outer ring areas at the bottom of the liquid storage chamber 11, respectively. Adjacent annular gas distribution pipes 311 are interconnected by a connecting pipe 312, so that the gas pressure among the annular gas distribution pipes 311 remains balanced. In other embodiments, the gas distribution network 31 may also be designed as a grid-like gas distribution network.

[0069] An air inlet is provided on the connecting pipe 312. The air inlet extends out of the pressure tank 1 through a pipe and is connected to an external inert gas supply source. In this embodiment, the inert gas is nitrogen, preferably cryogenic nitrogen.

[0070] The gas distribution network 31 has multiple bubbling holes 3121 facing upwards towards the liquid storage chamber 11. The bubbling holes 3121 are evenly distributed on each annular gas distribution pipe 311, and the diameter of each bubbling hole 3121 is 1-3 mm. Inert gas enters the gas distribution network 31 from an external gas source through the gas inlet interface. After being evenly distributed in each annular gas distribution pipe 311, it is released from the bubbling holes 3121, forming a large number of tiny bubbles. Under the action of buoyancy, the bubbles rise from the bottom of the liquid storage chamber 11 to the liquid surface. During their ascent, they drive the surrounding electrolyte to move, creating a bottom-up turbulence effect, which fully stirs and mixes the electrolyte in the entire liquid storage chamber 11, effectively preventing electrolyte concentration stratification and temperature unevenness. After reaching the liquid surface, the bubbles burst, releasing the inert gas into the gas phase space 111, replenishing the gas phase space 111 with an inert atmosphere.

[0071] By bubbling low-temperature nitrogen gas into the liquid phase through the bubbling device 3, the electrolyte can be cooled down and turbulence can be increased in the electrolyte, which helps to improve the temperature and concentration uniformity of ultra-large volume electrolytes.

[0072] Reference Figure 1 and Figure 4The gas phase space 111 is equipped with a protective gas pipeline assembly 14 and a hydrogen concentration detector 15. The protective gas pipeline assembly 14 includes a nitrogen inlet pipeline 141 and a forced exhaust pipeline 142. The nitrogen inlet pipeline 141 is used to supply high-purity nitrogen into the gas phase space 111 to maintain the inert atmosphere of the gas phase space 111, and the forced exhaust pipeline 142 is used to exhaust the gas in the gas phase space 111.

[0073] A linkage control valve 16 is installed on the nitrogen inlet pipe 141 and the forced exhaust pipe 142 respectively. The linkage control valve 16 is a solenoid valve or a pneumatic valve. The linkage control valve 16 is connected to the hydrogen concentration detector 15, that is, the detection signal output terminal of the hydrogen concentration detector 15 and the control signal input terminal of the linkage control valve 16 are connected through a signal cable or wireless communication.

[0074] A hydrogen concentration detector 15 is installed in the gas phase space 111 to monitor the hydrogen volume concentration in the gas phase space 111 in real time. During the charging and discharging process of the flow battery, a small amount of hydrogen may be generated in the electrolyte due to side reactions (such as hydrogen evolution reaction). After the hydrogen escapes from the liquid surface, it accumulates in the gas phase space 111. When the hydrogen concentration detector 15 detects that the hydrogen concentration in the gas phase space 111 reaches a preset threshold, the hydrogen concentration detector 15 sends an opening signal to the linkage control valve 16. The linkage control valve 16 automatically opens, and the nitrogen input pipeline 141 delivers high-purity nitrogen into the gas phase space 111. At the same time, the forced exhaust pipeline 142 discharges the hydrogen-containing gas, realizing the scavenging and replacement of the gas phase space 111. After the hydrogen concentration drops below the safe range, the linkage control valve 16 closes, restoring the normal nitrogen protection state.

[0075] The inert gas bubbled into the electrolyte by the bubbling device 3 is released into the gas phase space 111 after the bubbles reach the liquid surface. This continuously replenishes the inert atmosphere in the gas phase space 111 and works in conjunction with the scavenging function of the protective gas tube group 14 to maintain a safe atmosphere environment in the gas phase space 111.

[0076] A gas phase pressure detector is also installed within the gas phase space 111 to monitor the gas pressure within the gas phase space 111 in real time. A temperature detection device 17 is also installed on the inner wall of the liquid storage chamber 11. The temperature detection device 17 includes a liquid phase immersion temperature probe and a gas phase electronic temperature probe. The liquid phase immersion temperature probe is immersed in the electrolyte to detect the electrolyte temperature, while the gas phase electronic temperature probe is located within the gas phase space 111 to detect the gas phase temperature. A liquid level detection device, which employs a radar level gauge, is also installed within the liquid storage chamber 11 to monitor the electrolyte level parameters in real time.

[0077] Reference Figure 1 and Figure 5The storage chamber 11 is equipped with an inlet pipe 18 and an outlet pipe 19. The inlet pipe 18 enters from the top of the pressure tank 1 and extends to the top of the storage chamber 11, and the inlet pipes 18 are distributed in the area near the side wall of the pressure tank 1, that is, the outlet of the inlet pipe 18 is located in the upper outer ring area of ​​the storage chamber 11. In this embodiment, multiple inlet pipes 18 are provided, and the multiple inlet pipes 18 are distributed along the side wall of the pressure tank 1.

[0078] The outlet pipe 19 is located at the bottom of the liquid storage chamber 11 and distributed in the central area of ​​the liquid storage chamber 11. The port of the outlet pipe 19 extends into the lowest slope of the liquid storage chamber 11, and the port of the outlet pipe 19 near the bottom of the liquid storage chamber 11 is designed as a funnel shape. The diameter of the funnel-shaped port gradually increases from bottom to top, which increases the liquid absorption area, reduces the flow velocity at the port, and reduces the disturbance when the electrolyte is absorbed.

[0079] The outlet pipe 19 is equipped with an outlet pipe bracket 191 for fixed support. The entire outlet pipe 19 has multiple inlet pipes connected in parallel. A filter element 192 is provided at the port of the outlet pipe 19. In this embodiment, the filter element 192 is a filter screen to filter impurity particles and precipitates in the electrolyte and prevent impurities from entering the circulation pipe and the battery stack.

[0080] The layout of the liquid inlet pipe 18 entering the liquid at the upper part of the outer ring and the liquid outlet pipe 19 exiting the liquid at the bottom center works in conjunction with the bottom-up bubble turbulence of the bubbling device 3: the liquid enters from the upper part of the outer ring and exits from the bottom center. Together with the bottom-up bubble turbulence generated by the bubbling device 3, the three elements form a composite three-dimensional flow field in the liquid storage chamber 11, promoting the all-round mixing of the electrolyte in the liquid storage chamber 11.

[0081] The implementation principle of a gigawatt-hour flow battery storage tank in this application embodiment is as follows: Before the system is started, nitrogen is first introduced into the gas phase space 111 through the protective gas pipe group 14 to replace the atmosphere, ensuring that the oxygen concentration in the gas phase space 111 drops below the safe level and establishing an inert atmosphere protective environment.

[0082] During normal operation, the leak detector 2212 remains in standby mode. When the impermeable layer 21 within the liquid storage chamber 11 experiences partial damage, electrolyte may seep out. If the electrolyte further penetrates the leak-proof structural layer 23 (usually at the weakest weld), the leaked liquid will fall into the guide channel 2211. The liquid flows along the grid-like channels of the guide channel 2211 until it converges at one or more intersections. Upon contact with the liquid, the leak detector 2212 at each intersection undergoes a change in its physical or chemical properties (such as a change in resistance), triggering an alarm signal to be sent to an external monitoring system. This signal contains the location information of the leak detector 2212, allowing the monitoring system to pinpoint the leak location.

[0083] When the detected hydrogen concentration exceeds a preset safety threshold, the hydrogen concentration detector 15 sends an opening command to the linked control valve 16. Upon receiving the command, the linked control valve 16 automatically opens, thereby initiating the purging procedure of the protective gas pipeline group 14: the forced exhaust pipeline 142 begins to discharge the mixed gas in the gas phase space 111, while the nitrogen input pipeline 141 replenishes the gas phase space 111 with inert nitrogen. Through this replacement process, the hydrogen concentration in the gas phase space 111 is diluted and reduced. When the hydrogen concentration detector 15 detects that the hydrogen concentration has fallen back below the safety threshold, the linked control valve 16 closes, the purging process stops, and the system returns to the normal nitrogen protection state.

[0084] Simultaneously, when the electrolyte needs to be mixed within the storage chamber 11, the external inert gas (such as cryogenic nitrogen) supply is activated. The inert gas enters the gas distribution network 31 through the gas inlet. Subsequently, the gas escapes from the bubbling holes 3121, forming a large number of bubbles in the electrolyte. Under the action of buoyancy, the bubbles move from the bottom of the storage chamber 11 to the upper liquid surface. This movement drives the surrounding electrolyte to generate vertical convection from bottom to top, thereby forming an overall circulating flow field within the entire storage chamber 11. This fully agitates and mixes the electrolyte in different areas and at different depths, ultimately making the concentration and temperature of the electrolyte tend to be uniform.

[0085] When the system is shut down, the gas supply to the circulating pump group 52 and the bubbling device 3 is turned off, and the nitrogen protection state of the protective gas pipe group 14 is maintained to keep the gas phase space 111 inert atmosphere and prevent the electrolyte from being oxidized during shutdown.

[0086] This application also discloses a flow battery energy storage system.

[0087] Reference Figure 6 and Figure 7 A flow battery energy storage system includes at least two gigawatt-hour-level flow battery storage tanks, a stack cluster 4, a fluid distribution module 5, and a heat exchange device 6 as described above.

[0088] In this embodiment, two gigawatt-hour flow battery electrolyte storage tanks are provided, and the two gigawatt-hour flow battery electrolyte storage tanks (hereinafter referred to as storage tanks) are used to store the positive electrode electrolyte and the negative electrode electrolyte of the flow battery, respectively. The two tanks have the same structure.

[0089] The fuel cell cluster 4 comprises multiple individual fuel cell stacks 41 and an electrical control unit. The individual fuel cell stacks 41 are connected in series and / or parallel to achieve the conversion between electrical energy and chemical energy. The electrical control unit controls the charging and discharging status and operating parameters of each individual fuel cell stack 41. The individual fuel cell stacks 41 can be of various specifications, including 45kW, 125kW, and 200kW.

[0090] The fluid distribution module 5 includes a distribution network 51 and a circulation pump set 52 connected to the distribution network 51. The distribution network 51 forms a circulation loop connecting the pressure tank 1 and the fuel cell stack cluster 4 system. In this embodiment, the circulation pump set 52 is the main circulation variable frequency pump set, including multiple large corrosion-resistant magnetic variable frequency centrifugal pumps, to provide driving force for the flow of electrolyte in the circulation loop. The circulation pump set 52 adjusts the pump speed through a variable frequency controller, thereby adjusting the circulation flow rate of the electrolyte to adapt to the flow requirements under different charge and discharge powers.

[0091] In this embodiment, the positive electrolyte and the negative electrolyte each have independent distribution pipelines 51 and circulation pump groups 52, and the circulation loops of the positive electrolyte and the negative electrolyte are independent of each other.

[0092] The distribution network 51 adopts a reverse parallel pipeline design, including a main pipeline 511 and multiple branch pipelines 512. The main pipeline 511 includes a supply pipeline and a return pipeline. The supply pipeline is connected to the outlet pipeline 19, and the circulating pump set 52 is connected in series with the supply pipeline, thereby facilitating the supply of electrolyte to each individual fuel cell stack 41. The return pipeline is connected to the inlet pipeline 18, thereby facilitating the collection of electrolyte discharged from each individual fuel cell stack 41 and its return to the inlet pipeline 18. Each branch pipeline 512 is connected to the corresponding individual fuel cell stack 41, and each branch pipeline 512 includes a branch supply pipeline and a branch return pipeline.

[0093] The characteristic of the reverse parallel pipeline design is that the supply and return mains flow in opposite directions; that is, the flow direction of the electrolyte in the supply main is opposite to that in the return main. This design ensures that the total pipe length of each branch 512 is equal, resulting in a more balanced electrolyte flow rate and pressure drop distributed to each individual fuel cell stack 41. This helps to control the electrolyte inlet pressure difference pumped to each fuel cell stack module within ±5%, reducing concentration polarization and localized overheating problems caused by uneven electrolyte flow between fuel cell stacks due to pipe length differences.

[0094] The heat exchange device 6 is located outside the pressure tank 1. The heat exchange device 6 includes a heat exchange unit 61, a bypass pipeline 62, and a bypass regulating valve 63. The heat exchange unit 61 is connected in parallel with a section of the main pipeline 511 of the distribution network 51 through the bypass pipeline 62, so that when the electrolyte flows through this section of pipeline, it can either flow through the bypass pipeline 62 to the heat exchange unit 61 for heat exchange, or flow directly to the fuel cell stack cluster 4 through this section of the main pipeline 511.

[0095] The heat exchange unit 61 includes a heat exchanger cluster, which can be made of a non-metallic material with high thermal conductivity and acid resistance, specifically a silicon carbide (SiC) tubular heat exchanger array or a graphite plate heat exchanger array. Silicon carbide and graphite materials have extremely high thermal conductivity and excellent acid corrosion resistance, enabling long-term stable operation in strongly acidic electrolyte environments. The heat exchange unit 61 adopts a partitioned heat exchange principle, with the electrolyte flowing on one side of the heat exchanger and the cooling medium (such as cooling water or ethylene glycol solution) flowing on the other side. Heat exchange occurs between the two through the heat exchange walls, thereby achieving cooling or heating of the electrolyte. Taking a 4GWh / 1GW system as an example, to cope with the heat loss generated by full-load operation of 1GW power, a single-side system can be configured with 8 large non-metallic heat exchanger clusters, with a heat exchange surface area of ​​no less than 800m² for each heat exchanger.

[0096] A bypass regulating valve 63 is installed on the bypass pipeline 62. The bypass regulating valve 63 is an electric regulating valve or a pneumatic regulating valve, which can adjust its opening degree according to the control signal to achieve high-speed response.

[0097] During system operation, electrolyte is released from storage chamber 11 (refer to...) Figure 1 After being pumped out by the circulating pump set 52, the electrolyte flows along the main pipeline 511 of the distribution network 51. Based on the real-time temperature data of the electrolyte fed back by the temperature detection device 17, the system dynamically adjusts the opening of the bypass regulating valve 63 to control the proportion of electrolyte flow diverted to the heat exchange unit 61.

[0098] When the electrolyte temperature is too high and enhanced cooling is required, the opening of the bypass regulating valve 63 is increased, and the flow resistance of the bypass pipe 62 is reduced, so that a larger proportion of the electrolyte flows through the bypass pipe 62 to the heat exchange unit 61 for sufficient heat exchange. When the electrolyte temperature is within a suitable range, the opening of the bypass regulating valve 63 is reduced, and the flow resistance of the bypass pipe 62 is increased, so that more electrolyte flows directly through the parallel pipe section of the main pipe 511, reducing the load on the heat exchange unit 61 and the overall flow resistance of the system.

[0099] The heat exchange device 6 achieves temperature regulation outside the liquid storage tank, while the bubbling device 3 achieves turbulent mixing and auxiliary cooling inside the liquid storage tank. The two work together: the heat exchange device 6 controls the temperature of the electrolyte returning to the liquid storage chamber 11 by adjusting the flow rate of the electrolyte flowing through the heat exchange unit 61, and the bubbling device 3 assists in cooling and promotes uniform mixing of the electrolyte by blowing low-temperature nitrogen into the liquid storage chamber 11. The two work together to make the temperature distribution of the electrolyte in the liquid storage chamber 11 more uniform.

[0100] Through the precise temperature control of the heat exchange device 6, the temperature of the electrolyte flowing back into the storage chamber 11 can be strictly locked in the range of 10-40℃ under summer operating conditions, maintaining the electrolyte within the optimal reaction temperature range, thereby reducing the risk of vanadium ion crystallization and precipitation at high temperatures, and also reducing the risk of a large amount of electrolyte being contaminated and scrapped due to the rupture of the coolant pipeline.

[0101] The implementation principle of a flow battery energy storage system according to an embodiment of this application is as follows: Before the system is started, nitrogen gas is first introduced into the gas phase space 111 of each liquid storage tank through the protective gas pipe group 14 to replace the atmosphere and establish an inert atmosphere protective environment. Then, the circulation pump group 52 is started to begin electrolyte circulation.

[0102] During system operation, the circulating pump unit 52 draws electrolyte from the bottom of the storage chamber 11 through the outlet pipe 19 and pumps it into the main pipe 511. In the main pipe 511, the electrolyte is split at the parallel section; one part flows through the bypass pipe 62 to the heat exchange unit 61 for heat exchange, while the other part flows directly through the parallel section of the main pipe 511. Based on real-time temperature data, the system controls the proportion of electrolyte diverted to the heat exchange unit 61 by adjusting the bypass regulating valve 63, thereby maintaining the electrolyte temperature within the set operating range. Subsequently, the temperature-regulated electrolyte is evenly distributed to each individual battery stack 41 through the reverse-flow distribution network 51. Inside each individual battery stack 41, the electrolyte undergoes a redox reaction, achieving the storage or release of electrical energy. The reacted electrolyte flows out from each individual battery stack 41, merges into the main pipe 511, and then returns to the storage chamber 11 through the inlet pipe 18, completing one complete closed-loop cycle.

[0103] When the system is shut down, turn off the circulating pump group 52 and keep the protective gas pipe group 14 of each liquid storage tank in a nitrogen protection state.

[0104] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A gigawatt-hour-level flow battery liquid storage tank, characterized in that, include: Pressure tank (1), wherein a liquid storage chamber (11) is formed inside the pressure tank (1). The protective structure (2) includes at least one impermeable layer (21) and at least one detection layer (22). The detection layer (22) is disposed on the inner wall of the liquid storage cavity (11) and is used to monitor whether the impermeable layer (21) leaks. The impermeable layer (21) is disposed on the inner side of the detection layer (22) and is used to contact the electrolyte. A bubbling device (3) is disposed in the liquid storage chamber (11). The bubbling device (3) is used to deliver inert gas into the liquid storage chamber (11) to turbulently mix the electrolyte. The detection layer (22) includes a detection unit (221) and multiple insulation blocks (222). The multiple insulation blocks (222) are sequentially spliced ​​and laid on the inner wall of the liquid storage chamber (11). The detection unit (221) is embedded between the multiple insulation blocks (222). The detection unit (221) is used to monitor whether the seepage prevention layer (21) leaks. The detection unit (221) includes multiple guide channels (2211) laid between the insulation blocks (222). The multiple guide channels (2211) are crisscrossed to form a grid-like guide channel. A leakage detector (2212) is provided at the intersection of the multiple guide channels (2211). The protective structure (2) also includes a leak-proof structure layer (23), which is disposed between the detection layer (22) and the seepage-proof layer (21). The leak-proof structure layer (23) is made of spliced ​​metal plates, and the splicing seams between the metal plates are aligned with the flow channel (2211).

2. The gigawatt-hour-level flow battery storage tank according to claim 1, characterized in that: The bubbling device (3) includes a gas distribution network (31) laid along the bottom of the liquid storage chamber (11), and the gas distribution network (31) has a plurality of bubbling holes (3121) facing upwards from the liquid storage chamber (11).

3. The gigawatt-hour-level flow battery storage tank according to claim 2, characterized in that: The gas distribution network (31) includes at least two concentrically arranged annular gas distribution pipes (311), and adjacent annular gas distribution pipes (311) are connected to each other by a connecting pipe (312). The bubble holes (3121) are opened on the annular gas distribution pipes (311).

4. The gigawatt-hour-level flow battery storage tank according to claim 1, characterized in that: A gas phase space (111) is formed at the top of the liquid storage chamber (11). A protective gas tube assembly (14) and a hydrogen concentration detector (15) are installed in the gas phase space (111). A linkage control valve (16) is installed on the protective gas tube assembly (14). The linkage control valve (16) is connected to the hydrogen concentration detector (15). When the hydrogen concentration detector (15) detects that the hydrogen concentration in the gas phase space (111) reaches a preset threshold, the linkage control valve (16) opens to purge the gas phase space (111) through the protective gas tube assembly (14).

5. The gigawatt-hour-level flow battery storage tank according to claim 1, characterized in that: The liquid storage chamber (11) is provided with an inlet pipe (18) and an outlet pipe (19). The inlet pipe (18) enters from the top of the pressure tank (1) and extends to the top of the liquid storage chamber (11). The inlet pipe (18) is distributed in the area near the side wall of the pressure tank (1). The outlet pipe (19) is located at the bottom of the liquid storage chamber (11) and is distributed in the central area of ​​the liquid storage chamber (11). The port of the outlet pipe (19) near the bottom of the liquid storage chamber (11) is flared, and a filter element (192) is provided at the port.

6. A flow battery energy storage system, characterized in that, include: At least two gigawatt-hour flow battery storage tanks as described in any one of claims 1-5, wherein at least one serves as a positive electrode electrolyte storage tank and at least one serves as a negative electrode electrolyte storage tank; Fuel cell cluster (4); The fluid distribution module (5) includes a distribution network (51) and a circulation pump group (52) connected to the distribution network (51). The distribution network (51) forms a circulation loop connecting the liquid storage tank and the fuel cell stack (4). A heat exchange device (6) is installed outside the liquid storage tank of the gigawatt-hour flow battery. The heat exchange device (6) includes a heat exchange unit (61), a bypass pipeline (62), and a bypass regulating valve (63). The heat exchange unit (61) is connected in parallel to the distribution network (51) through the bypass pipeline (62). The bypass regulating valve (63) is installed on the bypass pipeline (62) and is used to regulate the flow rate of electrolyte flowing through the bypass pipeline (62).

7. The flow battery energy storage system according to claim 6, characterized in that: The fuel cell stack cluster (4) includes multiple individual fuel cell stacks (41). The distribution network (51) adopts a reverse parallel network design. The distribution network (51) includes a main pipeline (511) and multiple branch pipelines (512). Each branch pipeline (512) is connected to the corresponding individual fuel cell stack (41). The total pipeline length of each branch pipeline (512) is equal.

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