Flywheel energy storage system

Abstract

This invention discloses a flywheel energy storage system, comprising: a cover, a housing, an outer flywheel, an inner rotor, a stator, and a shaft; the cover and housing are detachably connected to form a sealed receiving cavity, within which the outer flywheel, inner rotor, stator, and shaft are all disposed. The outer flywheel and shaft are interference-fitted together. The inner rotor and stator are disposed between the shaft and the outer flywheel and distributed radially along the shaft. The inner rotor is interference-fitted to the shaft, and a cover plate is provided at the end of the inner rotor so that the outer flywheel, inner rotor, and shaft together constitute the flywheel rotor for energy storage. Cooling water pipes are disposed within the stator. This flywheel energy storage system utilizes the structural design of the outer flywheel, enabling the outer flywheel, inner rotor, and shaft to collectively constitute the flywheel rotor of the system, thereby improving the energy storage efficiency. Furthermore, the structural design of the inner rotor and stator further reduces energy loss and heat generation during operation, improving heat dissipation efficiency.

Description

Technical Field

[0001] This invention relates to the field of flywheel energy storage, and specifically discloses a flywheel energy storage system. Background Technology

[0002] Flywheel energy storage systems, as an advanced physical energy storage technology, store electrical energy in the form of kinetic energy through a high-speed rotating flywheel. They offer significant advantages such as rapid charging and discharging, long cycle life, and environmental friendliness. Therefore, flywheel energy storage technology shows broad application prospects in areas such as power system frequency regulation, uninterruptible power supplies, energy recovery in rail transit, and grid connection of new energy sources.

[0003] Flywheel energy storage systems, controlled by a controller, achieve the mutual conversion of electrical energy into mechanical energy. Depending on their operating state, flywheel energy storage systems are divided into charging, standby, and discharging states. To improve the energy conversion efficiency of flywheel energy storage systems, they minimize no-load standby losses; therefore, flywheel energy storage systems typically operate in a vacuum environment, using a coreless stator structure to eliminate stator core losses. However, coreless flywheel energy storage systems often face challenges in heat dissipation for the windings and permanent magnets.

[0004] Therefore, there is an urgent need for a flywheel energy storage system with high energy conversion efficiency and good heat dissipation. Summary of the Invention

[0005] (a) Technical problems to be solved Based on this, the present invention provides a flywheel energy storage system, which utilizes the structure of an outer flywheel such that the outer flywheel, inner rotor, and shaft together constitute the flywheel rotor of the flywheel energy storage system, thereby improving the energy storage efficiency of the flywheel energy storage system. The structure of the inner rotor and stator further reduces energy loss and heat generation during the operation of the flywheel energy storage system, thereby improving heat dissipation efficiency.

[0006] (II) Technical Solution To solve the above-mentioned technical problems, the present invention proposes a flywheel energy storage system, which includes: a cover, a housing, an outer flywheel, an inner rotor, a stator, and a shaft; The cover and housing are detachably connected to form a sealed cavity. The outer flywheel, inner rotor, stator and shaft are all disposed in the cavity. The outer flywheel and shaft are interference-fitted. The inner rotor and stator are disposed between the shaft and the outer flywheel and are distributed one by one along the radial direction of the shaft. The inner rotor is interference-fitted to the shaft. The end of the inner rotor is provided with a cover plate so that the outer flywheel, inner rotor and shaft together constitute a flywheel rotor energy storage. Cooling water pipes are disposed inside the stator.

[0007] Preferably, the rotating shaft includes an inner rotor connecting section, a protruding section, and a bearing section; The paired bearing segments are located at both ends of the rotating shaft to connect the machine covers at both ends. The diameter of the inner rotor connecting segment is larger than the diameter of the bearing segment and is located between the paired bearing segments. The inner rotor connecting segment is connected to the inner rotor. The diameter of the protruding segment is larger than the diameter of the inner rotor connecting segment and one end of the inner rotor abuts against the protruding segment. The other end of the inner rotor is provided with the cover plate and the end of the cover plate is connected to the inner rotor connecting segment. The inner rotor connecting segment, the protruding segment and the bearing segment are integrally formed.

[0008] Preferably, the inner rotor is embedded with a permanent magnet assembly, which includes multiple permanent magnet segments connected to each other along the axial direction of the inner rotor.

[0009] Preferably, the stator includes a support frame made of non-magnetic and non-conductive material, stator windings, and the cooling water pipes; The outer flywheel has an installation groove, the support frame is disposed in the installation groove, the stator winding is disposed on the support frame, and the cooling water pipe is disposed between adjacent stator windings.

[0010] Preferably, the cooling water pipe includes a U-shaped water pipe and sealing resin disposed at both ends of the U-shaped water pipe.

[0011] Preferably, the cover includes an upper cover plate and a lower cover plate, which are detachably connected to both ends of the housing.

[0012] Preferably, the housing includes a shell, an upper end cover, a lower end cover, an upper mechanical bearing, and a lower mechanical bearing; The housing is provided with an upper end cover and a lower end cover at its two ends respectively. The upper mechanical bearing and the lower mechanical bearing are respectively provided at the center of symmetry of the upper end cover and the lower end cover. The upper mechanical bearing and the lower mechanical bearing are respectively connected to the bearing section of the rotating shaft.

[0013] (III) Beneficial Effects Compared with existing technologies, the flywheel energy storage system of the present invention has the following advantages: The present invention provides a flywheel energy storage system, which uses an outer flywheel and a rotating shaft. The cross-section of the outer flywheel is "L"-shaped and the rotating shaft has a protruding section near the L-shaped cross-section of the outer flywheel. Thus, the outer flywheel, the inner rotor, and the protruding section of the rotating shaft together constitute the flywheel rotor part of the flywheel energy storage system, thereby effectively improving the energy storage efficiency of the flywheel energy storage system.

[0014] The internal rotor and stator structure further reduces energy loss and heat generation during the operation of the flywheel energy storage system, improving heat dissipation efficiency. The internal cooling water pipes in the stator provide a heat dissipation channel, effectively removing heat and ensuring long-term, efficient, and stable operation of the flywheel energy storage system. The U-shaped water pipes arranged between each slot of the stator provide a heat dissipation channel, further removing heat and ensuring long-term stable operation of the flywheel energy storage system.

[0015] The permanent magnet is axially segmented and embedded in the inner rotor. The outer flywheel is interference-fitted with the shaft. The synchronous rotation of the outer flywheel and the shaft can keep the magnetic flux on the outer flywheel unchanged, thereby suppressing eddy current losses on the outer flywheel. Furthermore, the permanent magnet is embedded in the inner rotor, and the outer layer of the permanent magnet is equivalent to a shielding layer, which can effectively suppress and prevent armature reaction from generating eddy current losses on the permanent magnet. Moreover, the eddy current losses generated by the permanent magnet can be conducted away through the inner rotor and the shaft. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is an overall schematic diagram of the flywheel energy storage system of the present invention; Figure 2 This is a half-section schematic diagram of the flywheel energy storage system of the present invention; Figure 3 This is a schematic diagram of the coreless stator structure of the flywheel energy storage system of the present invention; Figure 4 This is a schematic diagram of the flywheel rotor structure of the flywheel energy storage system of the present invention; Figure 5 This is a schematic diagram of the structure of each component of the flywheel rotor in the flywheel energy storage system of the present invention; Figure 6 This is a schematic diagram of the inner rotor and cover plate of the flywheel energy storage system of the present invention. Figure 7 This is a schematic diagram of the inner rotor and shaft of the flywheel energy storage system of the present invention; Figure 8 This is a schematic diagram of the internal rotor of the flywheel energy storage system of the present invention; Figure 9 This is a schematic diagram of the axial segmented structure of the permanent magnet assembly in the flywheel energy storage system of the present invention.

[0018] Explanation of reference numerals in the attached figures: 1. Shaft; 1.1. Inner rotor connecting section; 1.2. Protruding section; 1.3. Bearing section; 2. Outer flywheel; 3. Inner rotor; 4. Stator; 5. Rotor cover plate; 6. Upper cover plate; 7. Upper mechanical bearing; 8. Upper end cover; 9. Housing; 10. Lower end cover; 11. Lower mechanical bearing; 12. Lower cover plate; 13. U-shaped water pipe; 14. Permanent magnet assembly. Detailed Implementation

[0019] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0020] The following is in conjunction with the appendix Figure 1-9 The flywheel energy storage system and its testing method of the present invention will be further described.

[0021] Please refer to this carefully. Figure 1-3 This invention discloses a flywheel energy storage system, which includes: a cover, a housing 9, an outer flywheel 2, an inner rotor 3, a stator 4, and a shaft 1; the cover and housing 9 are detachably connected to form a sealed receiving cavity, the outer flywheel 2, the inner rotor 3, the stator 4, and the shaft 1 are all disposed in the receiving cavity, the outer flywheel 2 and the shaft 1 are interference-fitted, the inner rotor 3 and the stator 4 are disposed between the shaft 1 and the outer flywheel 2 and are distributed one by one along the radial direction of the shaft 1, the inner rotor 3 is interference-fitted to the shaft 1, and the end of the inner rotor 3 is provided with a rotor cover plate 5 so that the outer flywheel 2, the inner rotor 3, and the shaft 1 together constitute a flywheel rotor energy storage, and a cooling water pipe is disposed inside the stator 4.

[0022] In this embodiment, the flywheel energy storage system utilizes the structure of an outer flywheel 2 and a shaft 1. The outer flywheel 2 has an "L"-shaped cross-section, and the shaft 1 has a protruding section 1.2 near the L-shaped cross-section of the outer flywheel 2. Thus, the outer flywheel 2, the inner rotor 3, and the protruding section 1.2 of the shaft 1 together constitute the flywheel rotor portion of the flywheel energy storage system, effectively improving its energy storage efficiency. Furthermore, the structure of the inner rotor 3 and the stator 4 further reduces energy loss and heat generation during operation, improving heat dissipation efficiency. The cooling water pipes inside the stator 4 provide a heat dissipation channel, effectively removing heat from the stator 4, thereby enabling the flywheel energy storage system to operate stably and efficiently for extended periods.

[0023] like Figure 2 , Figure 4 , Figure 5 and Figure 6 As shown, the rotating shaft 1 includes an inner rotor 3 connecting section 1.1, a protruding section 1.2, and a bearing section 1.3; the paired bearing sections 1.3 are located at both ends of the rotating shaft 1 to connect the machine covers at both ends. The diameter of the inner rotor 3 connecting section 1.1 is larger than the diameter of the bearing section 1.3 and is located between the paired bearing sections 1.3. The inner rotor 3 connecting section 1.1 is connected to the inner rotor 3. The diameter of the protruding section 1.2 is larger than the diameter of the inner rotor 3 connecting section 1.1 and one end of the inner rotor 3 abuts against the protruding section 1.2. The other end of the inner rotor 3 is provided with a rotor cover plate 5 and the end of the rotor cover plate 5 is connected to the inner rotor 3 connecting section 1.1. The inner rotor 3 connecting section 1.1, the protruding section 1.2, and the bearing section 1.3 are integrally formed.

[0024] In this embodiment, in order to match the structure of the outer flywheel 2, its shaft 1 is configured with multiple sections of different diameters. The protruding section 1.2 and the connecting section 1.1 of the inner rotor 3 are configured so that the inner rotor 3 can be installed between the outer flywheel 2 and the shaft 1. The bottom rotor cover plate 5 is configured to form a sealed space between the outer flywheel 2 and the protruding section 1.2 of the shaft 1. After the inner rotor 3 is installed in the sealed space, the sealed structure formed by the inner rotor 3, the outer flywheel 2 and the shaft 1 together constitutes the flywheel rotor of the flywheel energy storage system.

[0025] See Figures 7-9 The inner rotor 3 is embedded with a permanent magnet assembly 14, which includes multiple permanent magnet segments connected to each other along the axial direction of the inner rotor 3. In this embodiment, the shaft 1 is made of non-magnetic stainless steel. The shaft 1 is cooled at low temperature, and then the shaft 1 and the inner rotor 3 are interference-fitted. In a preferred embodiment, the inner rotor 3 has a V-shaped hole, and the axially segmented permanent magnet assembly 14 of the same polarity is embedded in the V-shaped hole of the inner rotor 3. Finally, the permanent magnets are sealed by the rotor cover plate 5 through interference sealing. The permanent magnet assembly 14 uses axially segmented multi-segment permanent magnets embedded in the inner rotor 3. The outer flywheel 2 is interference-fitted with the shaft 1. The synchronous rotation of the outer flywheel 2 and the shaft 1 can keep the magnetic flux on the outer flywheel 2 unchanged, thereby suppressing the eddy current loss on the outer flywheel 2. Since the permanent magnet is embedded in the inner rotor 3, the outer layer of the permanent magnet is equivalent to a shielding layer, which can effectively suppress and prevent armature reaction from generating eddy current loss on the permanent magnet. The eddy current loss generated by the permanent magnet can be conducted away through the inner rotor 3 and the shaft 1.

[0026] like Figure 2 and Figure 3As shown, the stator 4 includes a support frame made of non-magnetic and non-conductive material, stator 4 windings, and cooling water pipes; the outer flywheel 2 has a mounting groove, the support frame is disposed in the mounting groove, the stator 4 windings are disposed on the support frame, and cooling water pipes are disposed between adjacent stator 4 windings. The cooling water pipes include U-shaped water pipes 13 and sealing resin disposed at both ends of the U-shaped water pipes 13.

[0027] In this embodiment, the stator 4 of the flywheel energy storage system adopts a coreless structure, eliminating core losses and greatly suppressing wind friction losses by operating in a vacuum environment, thus improving the energy conversion efficiency of the flywheel energy storage system. However, the stator 4 material, being non-magnetic and non-conductive, has low thermal conductivity, leading to difficulties in heat dissipation. Therefore, the flywheel energy storage system arranges U-shaped water pipes 13 between adjacent stator 4 winding slots to provide a heat dissipation channel, efficiently removing heat from the stator 4 and enabling the flywheel energy storage system to operate stably for a long time. The stator 4 has a concentrated winding distribution, and the sealing resin used to seal both ends of the U-shaped water pipes 13 is preferably epoxy resin.

[0028] In this flywheel energy storage system, the housing includes an upper cover plate 6 and a lower cover plate 12, which are detachably connected to both ends of the housing 9. The housing 9 includes a shell, an upper end cover 8, a lower end cover 10, an upper mechanical bearing 7, and a lower mechanical bearing 11. The upper end cover 8 and the lower end cover 10 are respectively located at the ends of the shell. The upper mechanical bearing 7 and the lower mechanical bearing 11 are respectively located at the symmetrical centers of the upper end cover 8 and the lower end cover 10, and are respectively connected to the bearing section 1.3 of the rotating shaft 1. The upper cover plate 6, the upper end cover 8, the housing 9, the lower cover plate 12, and the lower end cover 10 together form a sealed space, and the flywheel rotor operates in a vacuum environment.

[0029] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components; and they can also refer to a "transmission connection," that is, a power connection through various suitable methods such as belt drive, gear drive, or sprocket drive. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

Claims

1. A flywheel energy storage system, characterized in that, The flywheel energy storage system includes: a cover, a housing, an outer flywheel, an inner rotor, a stator, and a shaft; The cover and housing are detachably connected to form a sealed cavity. The outer flywheel, inner rotor, stator and shaft are all disposed in the cavity. The outer flywheel and shaft are interference-fitted. The inner rotor and stator are disposed between the shaft and the outer flywheel and are distributed one by one along the radial direction of the shaft. The inner rotor is interference-fitted to the shaft. The end of the inner rotor is provided with a cover plate so that the outer flywheel, inner rotor and shaft together constitute a flywheel rotor energy storage. Cooling water pipes are disposed inside the stator.

2. The flywheel energy storage system according to claim 1, characterized in that, The rotating shaft includes an inner rotor connecting section, a protruding section, and a bearing section; The paired bearing segments are located at both ends of the rotating shaft to connect the machine covers at both ends. The diameter of the inner rotor connecting segment is larger than the diameter of the bearing segment and is located between the paired bearing segments. The inner rotor connecting segment is connected to the inner rotor. The diameter of the protruding segment is larger than the diameter of the inner rotor connecting segment and one end of the inner rotor abuts against the protruding segment. The other end of the inner rotor is provided with the cover plate and the end of the cover plate is connected to the inner rotor connecting segment. The inner rotor connecting segment, the protruding segment and the bearing segment are integrally formed.

3. The flywheel energy storage system according to claim 2, characterized in that, The inner rotor is embedded with a permanent magnet assembly, which includes multiple permanent magnet segments connected to each other along the axial direction of the inner rotor.

4. The flywheel energy storage system according to claim 3, characterized in that, The stator includes a support frame made of non-magnetic and non-conductive material, stator windings, and cooling water pipes; The outer flywheel has an installation groove, the support frame is disposed in the installation groove, the stator winding is disposed on the support frame, and the cooling water pipe is disposed between adjacent stator windings.

5. The flywheel energy storage system according to claim 4, characterized in that, The cooling water pipe includes a U-shaped water pipe and sealing resin disposed at both ends of the U-shaped water pipe.

6. The flywheel energy storage system according to claim 5, characterized in that, The cover includes an upper cover plate and a lower cover plate, which are detachably connected to both ends of the housing.

7. The flywheel energy storage system according to claim 6, characterized in that, The housing includes a shell, an upper end cover, a lower end cover, an upper mechanical bearing, and a lower mechanical bearing; The housing is provided with an upper end cover and a lower end cover at its two ends respectively. The upper mechanical bearing and the lower mechanical bearing are respectively provided at the center of symmetry of the upper end cover and the lower end cover. The upper mechanical bearing and the lower mechanical bearing are respectively connected to the bearing section of the rotating shaft.

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