A flywheel energy storage device and its installation method

Abstract

This application discloses a flywheel energy storage device and its installation method, relating to the field of energy storage equipment technology. The device includes a housing, a rotating shaft, and multiple rotors. The rotating shaft is rotatably connected inside the housing. The multiple rotors are sequentially installed on the rotating shaft along its axial direction and are circumferentially fixed to it. A receiving gap is provided between adjacent rotors. The housing includes an upper cover, a lower cover, and multiple cylindrical bodies disposed between them. The multiple cylindrical bodies are segmented along the axial direction. A stator is clamped and sealed between adjacent cylindrical bodies. The outer side of the stator is open to the atmosphere, and the inner side of the stator extends into the corresponding receiving gap. Permanent magnets are fixed on the rotors, and the permanent magnets are correspondingly arranged with the coil bodies on the stator. This solution can solve the problems of poor vacuum sealing and low assembly efficiency in the prior art.

Description

Technical Field

[0001] This application relates to the field of energy storage equipment technology, and in particular to a flywheel energy storage device and its installation method. Background Technology

[0002] Flywheel energy storage systems utilize a rotating flywheel to convert electrical energy into kinetic energy for storage, offering advantages such as long lifespan and high efficiency. However, most current flywheel energy storage devices use an integral vacuum container, requiring through-holes on the container surface for electrical connections and sensor placement, which complicates the vacuum sealing structure and increases maintenance costs. Furthermore, the limited assembly space between the multi-layered rotor and stator results in low installation efficiency and hinders large-scale production. In existing flywheel structures, the vacuum container is a metal barrel shape with densely distributed through-holes, requiring a high-power vacuum pump to maintain vacuum levels, and the internal assembly process is complex. Summary of the Invention

[0003] The purpose of this invention is to provide a flywheel energy storage device that solves the problems of poor vacuum sealing and low assembly efficiency in the prior art.

[0004] To achieve the above objectives, this application adopts the following technical solution: A flywheel energy storage device includes a housing, a shaft, and multiple rotors. The shaft is rotatably connected inside the housing. The multiple rotors are sequentially installed on the shaft along its axial direction and are circumferentially fixed to it. A accommodating gap is provided between adjacent rotors. The housing includes an upper cover, a lower cover, and multiple cylindrical bodies disposed between them. The multiple cylindrical bodies are segmented along the axial direction. A stator is clamped and sealed between adjacent cylindrical bodies. The outer side of the stator is in contact with the atmosphere, and the inner side of the stator extends into the corresponding accommodating gap. Permanent magnets are fixed on the rotors, and the permanent magnets are correspondingly arranged with the coil bodies on the stator.

[0005] In the above technical solution, due to the segmented layout of multiple cylinders and the orderly arrangement of multiple rotors, the assembly of the cylinders, stator, and rotors can be completed step by step during installation, reducing the depth to which the rotor and stator extend into the outer shell during each assembly, thereby reducing assembly complexity. The segmented design facilitates installation, maintenance, and replacement, enabling assembly in an assembly line manner, improving production efficiency and reducing production costs. Adjacent cylinders are clamped and sealed to the stator, with the stator's outer side open to the external atmosphere, eliminating the need for the original coil threading holes on the shell and enhancing the structural integrity and vacuum sealing performance of the outer shell. The inner side of the stator extends to the accommodating gap between the rotors, enabling efficient electromagnetic coupling between the coil body and the permanent magnet, while ensuring both energy conversion efficiency and mechanical stability. Furthermore, the alternating arrangement and coordinated operation of multiple rotors and stators can significantly improve the energy conversion power of the energy storage system, meeting the needs of high power density applications.

[0006] Preferably, the upper cover is separately disposed from the uppermost cylindrical body and is sealed and connected by a sealing structure, and the lower cover is separately disposed from the lowermost cylindrical body and is sealed and connected by a sealing structure.

[0007] In the above technical solution, the upper cover and the uppermost cylinder, and the lower cover and the lowermost cylinder are connected by a sealing structure to achieve a detachable sealed connection, which facilitates the individual processing of each part, helps to reduce the processing cost of parts and improve the flexibility of overall assembly.

[0008] Preferably, the mass of the rotor located at the bottom is greater than the mass of the rotors in the other positions.

[0009] In the above technical solution, by increasing the mass of the lowest rotor, the mass distribution of the entire rotating system can be effectively adjusted, the vibration amplitude during high-speed operation can be reduced, the stability and reliability of the system operation can be improved, and the overall rotational inertia of the system can be increased, which helps to increase the energy storage capacity and extend the continuous operation time of the energy storage device.

[0010] Preferably, two adjacent cylinders clamp the upper and lower end faces of the stator, and a sealing ring is provided at the clamping position.

[0011] In the above technical solution, by setting a sealing ring at the clamping point between the upper and lower end faces of adjacent cylinders and stator, the path of external gas entering the vacuum cavity along the interlayer gaps can be effectively blocked, further improving the sealing reliability. The sealing ring forms a surface contact seal with the stator end face, and combined with the axial clamping force between the cylinders, it ensures that excellent airtight performance is maintained even during long-term operation.

[0012] Preferably, the stator includes an upper plate, a lower plate, and a coil body disposed between the two. The upper plate is an integral structure, the lower plate is an integral structure, and the upper and lower plates are sealed and fixed to clamp the coil body. The inlet and outlet ends of the coil body pass through the stator to the atmosphere between the upper and lower plates.

[0013] In the above technical solution, the upper and lower plates adopt an integrated structural design, which can effectively avoid the reduction in airtightness and structural strength caused by splicing gaps, thereby ensuring the long-term stable operation of the stator in a high vacuum environment. The upper and lower plates are fixed and clamped to the coil body by upper and lower seals, and the inlet and outlet ends of the coil body are led out through the space between the upper and lower plates. The sealing connection between the upper and lower plates can achieve inter-plate sealing and prevent vacuum leakage.

[0014] Preferably, the upper plate and / or lower plate are provided with receiving grooves for accommodating the coil body.

[0015] In the above technical solution, by setting receiving grooves on the upper plate and / or lower plate, the coil body can be accurately positioned and firmly embedded inside the stator, effectively avoiding coil displacement caused by vibration, while improving the compactness and mechanical stability of the overall structure.

[0016] Preferably, a coil plate sealing ring is provided between the upper plate and the lower plate, and the upper plate and the lower plate clamp the coil plate sealing ring together, with the coil plate sealing ring located inside the coil body.

[0017] In the above technical solution, a double-sealed protection for the internal structure of the stator is achieved by clamping the coil plate sealing ring inside the coil body between the upper and lower plates, effectively isolating the vacuum cavity from leakage channels to the outside world. Because the coil plate sealing ring is located inside the coil body, even if there are minor defects in the seal between the upper and lower plates, or potential leakage risks at the inlet and outlet ends, the inner sealing ring can still effectively cut off the gas passage, ensuring the long-term stability of the vacuum environment. This sealing structure adopts an upper and lower clamping design, ensuring balanced force on the sealing ring and significantly enhancing the durability and reliability of the seal.

[0018] Preferably, the upper plate and the lower plate are sealed and fixed by filling with sealant; and / or, the upper plate and the lower plate are fastened and sealed by fasteners, the fasteners passing through the upper plate and the lower plate and cooperating with the sealing ring to achieve pre-tightening sealing.

[0019] In the above technical solution, sealing with sealant can effectively eliminate the microscopic gaps between the contact surfaces of the upper and lower plates, block gas permeation paths, and improve the airtightness of the sealing interface. Furthermore, this operation can be performed simultaneously with the coil body during factory processing, improving production efficiency and consistency. Using fasteners in conjunction with the sealing ring to achieve pre-tightening sealing ensures structural strength while allowing the sealing ring to be uniformly compressed, forming a stable and reliable sealing interface. The sealant and fasteners can be used individually or in combination to adapt to different vacuum levels and operating conditions.

[0020] Preferably, the outer wall of the cylinder is provided with a number of heat dissipation fins.

[0021] In the above technical solution, the heat dissipation fins are evenly distributed along the circumference of the outer wall of the cylinder, which increases the heat dissipation contact area between the cylinder and the external environment and effectively improves the heat conduction efficiency.

[0022] Preferably, the bottom of the housing is provided with a support.

[0023] A method for installing a flywheel energy storage device, based on the aforementioned flywheel energy storage device, further includes the following steps: Step 100: Hoist the bottommost cylinder and seal it with the lower cover; Step 200: Install the rotating shaft onto the lower cover and make the rotating shaft rotatably connected to the lower cover; Step 300: Place the bottom rotor onto the shaft; Step 400: Fit the stator onto the outside of the rotating shaft and make the cylinder support the stator; Step 500: Continue by fitting the next rotor onto the shaft; Step 600: Place the next cylinder on the outside of the rotating shaft and connect it with the lower cylinder, and clamp the upper and lower ends of the stator to achieve a sealed fixation; Step 700: Repeat steps 400 to 600 until all rotors and cylinders are assembled in sequence; Step 800: Install the top cover and rotate the upper end of the shaft to connect it to the top cover.

[0024] In the above technical solution, due to the segmented layout of multiple cylinders and the orderly arrangement of multiple rotors, the assembly of the cylinders, stator, and rotors can be completed step by step during installation, reducing the depth to which the rotor and stator extend into the outer shell during each assembly, thereby reducing assembly complexity. The segmented design facilitates installation, maintenance, and replacement, enabling assembly in an assembly line manner, improving production efficiency and reducing production costs. Adjacent cylinders are clamped and sealed to the stator, with the stator's outer side open to the external atmosphere, eliminating the need for the original coil threading holes on the shell and enhancing the structural integrity and vacuum sealing performance of the outer shell. The inner side of the stator extends to the accommodating gap between the rotors, enabling efficient electromagnetic coupling between the coil body and the permanent magnet, while ensuring both energy conversion efficiency and mechanical stability. Furthermore, the alternating arrangement and coordinated operation of multiple rotors and stators can significantly improve the energy conversion power of the energy storage system, meeting the needs of high power density applications. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of this application; Figure 2 This is a structural sectional view of this application; Figure 3 yes Figure 2 A magnified view of a section at point A in the middle; Figure 4 This is a schematic diagram of the stator structure in this application. Figure 1 ; Figure 5 This is a schematic diagram of the stator structure in this application. Figure 2 .

[0026] In the diagram: outer shell 1, upper cover 11, lower cover 12, cylinder 13, upper bearing seat 101, lower bearing seat 102, rotating shaft 2, rotor 3, accommodating gap 4, stator 5, upper plate 51, lower plate 52, inlet end 531, outlet end 532, accommodating groove 54, coil plate sealing ring 55, first magnetic ring 56, second magnetic ring 57, heat dissipation fins 6, sealing cover 7, bracket 8. Detailed Implementation

[0027] The present application will now be further described with reference to the accompanying drawings and specific embodiments.

[0028] Example 1: like Figures 1 to 5 As shown, a flywheel energy storage device includes a housing 1, a rotating shaft 2, and multiple rotors 3. The housing 1 is vacuum-sealed. The rotating shaft 2 is rotatably connected to the housing 1. The multiple rotors 3 are coaxially mounted on the rotating shaft 2 along its axial direction and are circumferentially fixed to it. A accommodating gap 4 is provided between adjacent rotors 3. The housing 1 includes an upper cover 11, a lower cover 12, and multiple cylindrical bodies 13 disposed between them. The multiple cylindrical bodies 13 are segmented along their axial direction. A stator 5 is clamped and sealed between adjacent cylindrical bodies 13. The outer side of the stator 5 is in contact with the atmosphere, and the inner side of the stator 5 extends into the corresponding accommodating gap 4. Permanent magnets are fixed on the rotors 3, and the permanent magnets are correspondingly arranged with the coil bodies on the stator 5. The stator has a flat ring structure.

[0029] In the above technical solution, multiple rotors 3 are coaxially sleeved outside the rotating shaft 2, and the interior of the outer shell 1 is in a vacuum state during equipment operation. Due to the segmented layout of multiple cylinders 13 and the orderly arrangement of multiple rotors 3, the assembly of cylinders 13, stator 5, and rotors 3 can be completed step by step during installation, reducing the depth to which rotors 3 and stator 5 extend into the outer shell 1 during each assembly, thereby reducing assembly complexity. The segmented design facilitates installation, maintenance, and replacement, enabling assembly in an assembly line manner, improving production efficiency and reducing production costs. Adjacent cylinders 13 are clamped and sealed to connect the stator 5, with the outside of the stator 5 open to the external atmosphere, eliminating the need for the original coil threading holes on the shell and enhancing the structural integrity and vacuum sealing performance of the outer shell 1. The inner side of the stator 5 extends to the accommodating gap 4 between the rotors 3, enabling efficient electromagnetic coupling between the coil body and the permanent magnet, while ensuring both energy conversion efficiency and mechanical stability. In addition, the alternating arrangement and coordinated operation of multiple rotors 3 and stator 5 can significantly improve the energy conversion power of the energy storage system, meeting the needs of high power density application scenarios. The coil body is not shown in the figure. In this application, the upper and lower ends of the rotating shaft 2 are fixed to the upper cover 11 and the lower cover 12 by bearings. The upper bearing and the lower bearing are respectively installed in the upper bearing seat 101 and the lower bearing seat 102, which are respectively arranged on the upper cover 11 and the lower cover 12. The upper bearing seat 101 and the lower bearing seat 102 are sealed to the upper cover 11 and the lower cover 12, preferably with O-rings.

[0030] Preferably, a first magnetic ring 56 is provided on the outer side of the coil body's inlet end 531, and the wire outside the inlet end 531 is wound around the first magnetic ring 56. A second magnetic ring 57 is provided on the outer side of the coil body's outlet end 532, and the wire outside the outlet end 532 is wound around the second magnetic ring 57. In this application, a single coil generally uses Litz wire twisted from multiple strands of fine wire. Due to voltage differences between the strands, circulating currents are generated inside the single coil, heating the coil and leading to the undesirable consequence of increased motor temperature. Therefore, in order to reduce circulating currents, the wires at the inlet end 531 and outlet end 532 of the coil body can be directly wound around the magnetic rings (without cutting the coil), forming an inductance and increasing the coil's impedance.

[0031] Preferably, the stator 5 includes an upper plate 51, a lower plate 52, and a coil body disposed between the two. The upper plate 51 is an integral structure, and the lower plate 52 is an integral structure. The upper plate 51 and the lower plate 52 are sealed and fixed together to clamp the coil body. The inlet end 531 and the outlet end 532 of the coil body pass through the stator 5 to the atmosphere between the upper plate 51 and the lower plate 52.

[0032] In the above technical solution, the upper plate 51 and the lower plate 52 adopt an integrated structural design, which can effectively avoid the reduction of airtightness and structural strength caused by splicing gaps, thereby ensuring the long-term stable operation of the stator 5 in a high vacuum environment. The upper plate 51 and the lower plate 52 are fixed and clamped to the coil body by upper and lower sealing, and the inlet end 531 and outlet end 532 of the coil body are led out through the space between the upper plate 51 and the lower plate 52. With the sealing connection between the upper plate 51 and the lower plate 52, the inter-plate sealing can be achieved, and the vacuum leakage can be prevented through this sealing connection. By allowing the outside of the stator 5 to contact the atmosphere, the coil body can directly pass through the stator 5 to the outside of the housing, without the need to open additional through holes on the housing 1, thereby avoiding the problem of reduced sealing performance caused by opening through holes on the housing 1. Moreover, the part of the coil body located inside the housing 1 is wrapped inside the upper plate 51 and the lower plate 52, and does not directly contact the internal space of the housing 1, forming an effective isolation between the coil body and the internal space of the housing 1, further improving the overall sealing performance and operational reliability of the device.

[0033] Preferably, the upper plate 51 and / or the lower plate 52 are provided with receiving grooves 54 for accommodating the coil body. In the above technical solution, by providing receiving grooves 54 in the upper plate 51 and / or the lower plate 52, the coil body can be accurately positioned and firmly embedded inside the stator 5, effectively avoiding coil displacement caused by vibration, while improving the compactness and mechanical stability of the overall structure.

[0034] Preferably, a coil plate sealing ring 55 is provided between the upper plate 51 and the lower plate 52, and the upper plate 51 and the lower plate 52 clamp the coil plate sealing ring 55 together. The coil plate sealing ring 55 is located inside the coil body.

[0035] In the above technical solution, the coil plate sealing ring 55 being located inside the coil body means that the coil plate sealing ring 55 is arranged in the radially inner region of the coil body and does not directly contact the coil body. The coil plate sealing ring 55 can be an O-ring, which has a certain elasticity and, when placed in the sealing groove, can prevent air from entering between the upper and lower planes. The sealing groove can be provided only on the upper plate 51, only on the lower plate 52, or both on the upper plate 51 and the lower plate 52. By clamping the coil plate sealing ring 55 inside the coil body between the upper plate 51 and the lower plate 52, double sealing protection of the internal structure of the stator 5 is achieved, effectively isolating the vacuum cavity from leakage channels to the outside. Because the coil plate sealing ring 55 is located inside the coil body, even if there are minor defects in the seal between the upper plate 51 and the lower plate 52, or potential leakage risks at the inlet end 531 and the outlet end 532, the inner sealing ring can still effectively cut off the gas passage and ensure the long-term stability of the vacuum environment. The sealing structure adopts an upper and lower compression design, which makes the sealing ring subjected to balanced force, significantly enhancing the durability and reliability of the seal.

[0036] Preferably, the upper plate 51 and the lower plate 52 are sealed and fixed by filling with sealant; the upper plate 51 and the lower plate 52 are fastened and sealed by fasteners, which pass through the upper plate 51 and the lower plate 52 and cooperate with the sealing ring to achieve pre-tightening sealing.

[0037] In the above technical solution, sealing with sealant can effectively eliminate the microscopic gaps between the contact surfaces of the upper plate 51 and the lower plate 52, block gas permeation paths, and improve the airtightness of the sealing interface. This operation can also be performed simultaneously with the coil body during factory processing, improving production efficiency and consistency. Furthermore, using a high-strength sealant can bond the upper plate 51, lower plate 52, and coil body together. After the sealant cures, the upper plate 51, lower plate 52, and coil body form a single ring plate, effectively improving the stiffness and strength of the stator and eliminating the catastrophic accident risk caused by stator deformation and contact with the rotor. This type of sealant must also have insulating properties to enhance the insulation performance of the coil inside the stator. Using fasteners in conjunction with the sealing ring to achieve pre-tightening sealing ensures structural strength while allowing the sealing ring to be uniformly compressed, forming a stable and reliable sealing interface. The sealant and fasteners can be used alone or in combination to adapt to different vacuum levels and operating conditions.

[0038] Preferably, the mass of the rotor 3 located at the bottom is greater than the mass of the rotors 3 located at other positions.

[0039] In the above technical solution, by increasing the mass of the bottom rotor 3, the mass distribution of the entire rotating system can be effectively adjusted, reducing the vibration amplitude during high-speed operation and improving the stability and reliability of the system. Simultaneously, increasing the overall rotational inertia of the system helps increase energy storage capacity and extend the continuous operating time of the energy storage device. Multiple rotors 3 can ensure efficient conversion between mechanical energy and electrical energy. The optimal solution is to make the mass of the bottom rotor 3 greater than the sum of the masses of the rotors 3 in other positions.

[0040] Preferably, two adjacent cylinders 13 clamp the upper and lower end faces of the stator 5, and a sealing ring is provided at the clamping position.

[0041] In the above technical solution, by setting a sealing ring at the clamping point between the upper and lower end faces of adjacent cylinders 13 and stator 5, the path of external gas entering the vacuum cavity along the interlayer gaps can be effectively blocked, further improving the sealing reliability. The sealing ring forms a surface contact seal with the end face of stator 5, and combined with the axial clamping force between cylinders 13, it ensures excellent airtight performance even under long-term operation. The sealing ring can be an O-ring, which has a certain degree of elasticity and can be placed in the sealing groove to prevent air from entering between the upper and lower planes. The sealing groove can be set on the side wall or lower surface of the cylinder.

[0042] Specifically, the outer wall of the cylinder 13 is provided with a plurality of heat dissipation fins 6. The bottom of the outer shell 1 is provided with a support 8. The upper cover 11 is provided with a communication port and a sealing cover 7 for sealing the communication port, the sealing cover 7 being detachably connected to the upper cover 11.

[0043] In the above technical solution, the heat dissipation fins 6 are evenly distributed along the circumference of the outer wall of the cylinder 13, increasing the heat dissipation contact area between the cylinder 13 and the external environment, and effectively improving the heat conduction efficiency. The bracket 8 is used to support the outer shell 1, so that it is stably placed on the ground or equipment base. The connection port is used to connect detection or maintenance equipment when necessary, and a vacuum pump can be connected to remove air from the cavity when evacuating the interior.

[0044] Understandably, in one embodiment, the upper cover 11 is integrally formed with the uppermost cylinder 13; the lower cover 12 is integrally formed with the lowermost cylinder 13. In the above technical solution, the upper cover 11 and the uppermost cylinder 13 are integrally formed, and the lower cover 12 and the lowermost cylinder 13 are integrally formed, which can reduce the sealing joints in the assembly process and improve the overall structural strength and vacuum sealing reliability.

[0045] Understandably, in another embodiment, the upper cover 11 and the uppermost cylinder 13 are separately configured and sealed together by a sealing structure, and the lower cover 12 and the lowermost cylinder 13 are separately configured and sealed together by a sealing structure. In the above technical solution, the separate upper cover 11 and the uppermost cylinder 13, and the lower cover 12 and the lowermost cylinder 13 are detachably sealed together by a sealing structure, facilitating individual processing of each part, reducing part processing costs, and improving the flexibility of overall assembly. A sealing ring can be provided between the two parts to achieve a reliable seal.

[0046] Example 2: A method for installing a flywheel energy storage device, based on the flywheel energy storage device described in Embodiment 1, further includes the following steps: Step 100: Hoist the lowest cylinder 13 and seal it with the lower cover 12; Step 200: Install the rotating shaft 2 onto the lower cover 12, and make the rotating shaft 2 rotatably connected to the lower cover 12 through the bearing; Step 300: Fit the bottom rotor 3 onto the rotating shaft 2; Step 400: The stator 5 is fitted onto the outside of the rotating shaft 2, and the cylinder 13 supports the stator 5; Step 500: Continue by fitting the next rotor 3 onto the rotating shaft 2; Step 600: Place the next cylinder 13 on the outside of the rotating shaft 2 and connect it with the lower cylinder 13, and clamp the upper and lower ends of the stator 5 to achieve sealing and fixation; Step 700: Repeat steps 400 to 600 until all rotors 3 and cylinders 13 are assembled in sequence; Step 800: Install the top cover 11 and rotatably connect the upper end of the rotating shaft 2 to the top cover 11 via bearings.

[0047] In the above technical solution, due to the segmented layout of multiple cylinders 13 and the orderly arrangement of multiple rotors 3, the assembly of the annular cylinder 13, stator 5, and rotor 3 can be completed step by step during installation, reducing the depth to which the rotor 3 and stator 5 extend into the outer shell 1 during each assembly, thereby reducing the complexity of assembly. The segmented design facilitates installation, maintenance, and replacement, enabling assembly in an assembly line manner, improving production efficiency and reducing production costs. Adjacent cylinders 13 are clamped and sealed to connect the stator 5, with the outside of the stator 5 open to the external atmosphere, eliminating the need for the original coil threading holes on the shell and enhancing the structural integrity and vacuum sealing performance of the outer shell 1. The inner side of the stator 5 extends to the accommodating gap 4 between the rotors 3, enabling efficient electromagnetic coupling between the coil body and the permanent magnet, while ensuring both energy conversion efficiency and mechanical stability. Furthermore, the alternating arrangement and coordinated operation of multiple rotors 3 and stator 5 can significantly improve the energy conversion power of the energy storage system, meeting the needs of high power density application scenarios.

Claims

1. A flywheel energy storage device, characterized in that, The device includes a housing, a rotating shaft, and multiple rotors. The rotating shaft is rotatably connected inside the housing. The multiple rotors are sequentially installed on the rotating shaft along its axial direction and are circumferentially fixed to the rotating shaft. There is a accommodating gap between two adjacent rotors. The housing includes an upper cover, a lower cover, and multiple cylindrical bodies located between the two. The multiple cylindrical bodies are arranged in segments along the axial direction. A stator is clamped and sealed between two adjacent cylindrical bodies. The outer side of the stator is in contact with the atmosphere, and the inner side of the stator extends into the corresponding accommodating gap. A permanent magnet is fixed on the rotor, and the permanent magnet is correspondingly arranged with the coil body on the stator.

2. The flywheel energy storage device according to claim 1, characterized in that, The upper cover is separately disposed from the uppermost cylindrical body and is sealed and connected by a sealing structure; the lower cover is separately disposed from the lowermost cylindrical body and is sealed and connected by a sealing structure.

3. The flywheel energy storage device according to claim 1, characterized in that, The mass of the rotor located at the bottom is greater than the mass of the rotors at the other positions.

4. The flywheel energy storage device according to claim 1, characterized in that, The stator includes an upper plate, a lower plate, and a coil body disposed between the two. The upper plate and the lower plate are integral structures. The upper and lower plates are sealed and fixed to clamp the coil body. The inlet and outlet ends of the coil body pass through the stator to the atmosphere between the upper and lower plates.

5. A flywheel energy storage device according to claim 4, characterized in that, The upper plate and / or lower plate are provided with receiving slots for accommodating the coil body.

6. A flywheel energy storage device according to claim 4, characterized in that, A coil plate sealing ring is provided between the upper plate and the lower plate. The upper plate and the lower plate clamp the coil plate sealing ring tightly. The coil plate sealing ring is located inside the coil body.

7. A flywheel energy storage device according to claim 4, characterized in that, The upper plate and the lower plate are sealed and fixed by filling with sealant; and / or, the upper plate and the lower plate are fastened and sealed by fasteners, the fasteners passing through the upper plate and the lower plate and cooperating with the sealing ring to achieve pre-tightening sealing.

8. A flywheel energy storage device according to claim 1, characterized in that, The outer wall of the cylinder is provided with several heat dissipation fins.

9. A flywheel energy storage device according to claim 1, characterized in that, The bottom of the outer casing is provided with a support.

10. A method for installing a flywheel energy storage device, characterized in that, Based on the flywheel energy storage device of claim 1, the method further includes the following steps: Step 100: Hoist the bottommost cylinder and seal it with the lower cover; Step 200: Install the rotating shaft onto the lower cover and make the rotating shaft rotatably connected to the lower cover; Step 300: Place the bottom rotor onto the shaft; Step 400: Fit the stator onto the outside of the rotating shaft and make the cylinder support the stator; Step 500: Continue by fitting the next rotor onto the shaft; Step 600: Place the next cylinder on the outside of the rotating shaft and connect it with the lower cylinder, and clamp the upper and lower ends of the stator to achieve a sealed fixation; Step 700: Repeat steps 400 to 600 until all rotors and cylinders are assembled in sequence; Step 800: Install the top cover and rotate the upper end of the shaft to connect it to the top cover.

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