Flywheel energy storage device

Abstract

The flywheel energy storage device comprises a shell, a cavity is formed along the periphery of the inner wall of the shell and used for containing a rotor, and a rotating shaft is inserted into the bottom of the cavity from the exterior of the shell along the center axis of the shell; at least two groups of rotors are arranged, the rotors can rotate along with the rotating shaft at the same time, and when the rotors rotate, the distances between the rotors and the rotating shaft can be changed according to the change of centrifugal force. When the rotor can change the distance between the rotor and the rotating shaft along with the change of the rotating speed in the charging and discharging process, the rotational inertia of the flywheel rotor can also change along with the change of the rotating speed, the rotational inertia of the whole rotor system is changed, and therefore energy storage and energy discharging are achieved. Through the change of the rotational inertia of the flywheel rotor, the flywheel energy storage device does not have gear limitation in the charging and discharging processes, the charging amount can be instantly increased or the discharging amount can be instantly reduced, adjustment is flexible, and primary and secondary frequency modulation instructions of a power grid can be well matched.

Description

Technical Field

[0001] The present invention relates to the field of flywheel energy storage, in particular to a flywheel energy storage device. Background Art

[0002] Flywheel energy storage is an advanced physical energy storage technology that uses a motor to drive a flywheel to rotate at high speed to store energy. When needed, the flywheel drives a generator to generate electricity, releasing the energy. The operating principle of a flywheel energy storage device is based on the law of conservation of energy and the law of kinetic energy. It uses a reciprocating motor / generator to achieve the conversion and storage of electrical and mechanical energy.

[0003] Flywheel energy storage technology has achieved significant breakthroughs in reciprocal bidirectional motors for electric / generated power, high-speed rotating body design, and control systems. Several domestic companies have successfully developed megawatt-class flywheel energy storage devices and commercialized them. Flywheel energy storage equipment is suitable for applications in power systems (e.g., power stabilization and peak-load shifting), transportation (e.g., electric vehicles and drones), and industry (e.g., energy conservation and emission reduction, and production process optimization).

[0004] The flywheel rotor is the core component of a flywheel energy storage device. High-capacity and high-power flywheel rotors are often made of alloy steel to increase their individual capacity and storage capacity. Currently, flywheel energy storage rotors are cylindrical, resulting in a stable moment of inertia during rotation, making them difficult to adjust flexibly and adapting quickly to irregular changes in the grid's primary and secondary frequency regulation. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is that the flywheel energy storage rotor is cylindrical, the rotational inertia is stable during rotation, and it cannot be flexibly adjusted and cannot quickly adapt to the irregular changes in the primary and secondary frequency modulation of the power grid.

[0006] The above technical problem is solved by the following technical solution: The present invention proposes a flywheel energy storage device, which includes a shell, a cavity formed along the periphery of the inner wall of the shell for placing a rotor, and the rotating shaft is inserted into the bottom of the cavity from the outside of the shell along the central axis of the shell; the rotors are provided in at least two groups, and the rotors are arranged circumferentially with the rotating shaft as the center. The rotors can rotate simultaneously with the rotating shaft, and when the rotors rotate, the distance between the rotors and the rotating shaft can change according to the change of centrifugal force.

[0007] In a preferred embodiment of the flywheel energy storage device of the present invention, the rotor is connected to the rotating shaft via a connecting member, and the connecting member enables the distance between the rotor and the rotating shaft to be changed by changing the rotation speed of the rotating shaft; changing the distance between the rotor and the rotating shaft by changing the rotation speed of the rotating shaft is used to change the rotor mass distribution radius, so that the rotational inertia changes synchronously.

[0008] In a preferred embodiment of the flywheel energy storage device of the present invention, the connecting member includes a tension spring, one end of the tension spring is connected to the rotating shaft, and one end of the tension spring is connected to the rotor.

[0009] In a preferred embodiment of the flywheel energy storage device of the present invention, the connecting member further comprises a connecting shaft, the connecting shaft comprises a first end and a second end, the first end is connected to the rotating shaft, and the second end passes through the rotor.

[0010] In a preferred embodiment of the flywheel energy storage device of the present invention: the diameter of the first end of the connecting shaft is smaller than the diameter of the second end; the second end passes through the rotor and is connected to the limit plate.

[0011] In a preferred embodiment of the flywheel energy storage device of the present invention: the rotor is provided with a through hole along the transverse central axis, the diameter of the through hole is larger than the diameter of the second end portion, and the diameter of the through hole is smaller than the diameter of the limiting plate.

[0012] In a preferred embodiment of the flywheel energy storage device of the present invention: the inner wall of the rotor is further provided with an accommodating cavity, which is communicated with the through hole; a return spring is connected to the accommodating cavity, and a resistance block is connected to the end of the return spring, and an arc groove is provided at the end of the resistance block away from the return spring, and the arc groove is adapted to the outer wall of the connecting shaft.

[0013] In a preferred embodiment of the flywheel energy storage device of the present invention, the bottom end of the rotor contacts the end of the fixed disk, and a passive axial permanent magnet is provided at the bottom end of the fixed disk.

[0014] In a preferred embodiment of the flywheel energy storage device of the present invention, an active axial permanent magnet is provided on the bottom end surface of the cavity, and the passive axial permanent magnet is opposite to the active axial permanent magnet.

[0015] In a preferred embodiment of the flywheel energy storage device of the present invention: one end of the rotating shaft is inserted into the cavity from the end of the shell along the central axis of the shell and passes through the fixed disk to be connected to the active axial permanent magnet; the other end of the rotating shaft is connected to a reciprocal bidirectional motor.

[0016] The beneficial effect of the present invention is that by changing the flywheel rotor from a whole into multiple rotors, when the distance between the rotor and the rotating shaft can change as the rotation speed changes during the charging and discharging process, the rotational inertia of the flywheel rotor will also change accordingly, bringing about a change in the rotational inertia of the entire rotor system, thereby realizing energy storage and release.

[0017] The present invention changes the rotational inertia of the flywheel rotor so that the output and input power of the flywheel energy storage device are flexible and changeable during the charging and discharging process, without gear restrictions, and can instantly increase the charging amount or instantly reduce the discharging amount. The adjustment is flexible and can well match the primary and secondary frequency modulation instructions of the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings of the embodiments of the present invention. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention. Among them:

[0019] Figure 1 Shows the overall structural schematic diagram of the flywheel energy storage device;

[0020] Figure 2 Shows the internal structure of the flywheel energy storage device Figure 1 ;

[0021] Figure 3 Shows the internal structure of the flywheel energy storage device Figure 2 ;

[0022] Figure 4 A partial structural cross-sectional view of a flywheel energy storage device is shown;

[0023] Figure 5 Shows the internal structure of the flywheel energy storage device Figure 3 ;

[0024] Figure 6 A schematic diagram of the friction block structure of a flywheel energy storage device is shown.

[0025] In the figure: 1. Housing; 2. Rotor; 21. Through hole; 22. Return spring; 23. Contact block; 24. Arc groove; 3. Rotating shaft; 4. Connecting piece; 41. Tension spring; 42. Connecting shaft; 421. First end; 422. Second end; 43. Limiting plate; 5. Fixed plate; 6. Passive axial permanent magnet; 7. Active axial permanent magnet; 8. Reciprocal bidirectional motor. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below with reference to specific embodiments and the accompanying drawings.

[0027] The terms used in the present invention are those commonly used in the art in view of the functions of the present invention, but these terms may vary according to the intentions of those skilled in the art, precedents, or new technologies in the art. In addition, specific terms may be selected by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the present invention. Therefore, the terms used in the specification should not be understood as simple names, but rather as the meanings of the terms and the overall description of the present invention.

[0028] Reference Figures 1 to 6 This embodiment provides a flywheel energy storage device, including a housing 1, a cavity 11 formed along the inner periphery of the housing 1 for accommodating a rotor 2, and a rotating shaft 3 inserted from the outside of the housing 1 into the bottom of the cavity 11 along the central axis of the housing 1;

[0029] There are at least two groups of rotors 2, which are arranged around the rotating shaft 3. The rotors 2 can rotate simultaneously with the rotating shaft 3. When the rotors 2 rotate, the distance between the rotors 2 and the rotating shaft 3 can be changed according to the change of centrifugal force. Figure 1 In the figure, there are 6 groups of rotors 2, and the rotors 2 are arranged circumferentially with the rotating shaft 3 as the center.

[0030] The rotor 2 is connected to the rotating shaft 3 via a connecting member 4. The connecting member 4 enables the distance between the rotor 2 and the rotating shaft 3 to be changed by changing the rotation speed of the rotating shaft 3.

[0031] By changing the rotation speed of the rotating shaft 3 , the distance between the rotor 2 and the rotating shaft 3 is changed, so as to change the mass distribution radius of the rotor 2 , thereby causing the moment of inertia to change synchronously.

[0032] It should be noted that the function of the connector 4 is to connect the rotor 2 and the shaft 3. At the same time, the connector 4 can also adapt to the distance change between the rotor 2 and the shaft 3 and provide a linear space for the distance change between the rotor 2 and the shaft 3.

[0033] Reference Figure 2 and Figure 5 Specifically, when the rotation speed of the rotating shaft 3 increases, the centrifugal force on the rotor 2 also increases. At this time, the rotor 2 moves toward the inner wall of the shell 1 under the action of the centrifugal force. At this time, the distance between the rotor 2 and the rotating shaft 3 increases. When the distance between the rotor 2 and the rotating shaft 3 increases, the mass distribution radius of the entire rotor 2 increases, and the rotational inertia of the flywheel rotor 2 further increases, thereby improving the energy storage capacity of the flywheel rotor 2.

[0034] When the rotation speed of the rotating shaft 3 decreases, the centrifugal force on the rotor 2 also decreases. At this time, the rotor 2 senses the change in centrifugal force and moves toward the rotating shaft 3. When the rotor 2 moves toward the rotating shaft 3, the distance between the rotor 2 and the rotating shaft 3 decreases. When the distance between the rotor 2 and the rotating shaft 3 decreases, the mass distribution radius of the entire rotor 2 decreases, and the rotational inertia of the flywheel rotor 2 is further reduced, so that the flywheel rotor 2 can quickly convert energy into electricity and release it.

[0035] By changing the flywheel rotor 2 from a whole into multiple rotors 2, when the distance between the rotor 2 and the rotating shaft 3 can change as the rotation speed of the rotor 2 changes during the charging and discharging process, the rotational inertia of the flywheel rotor 2 will also change accordingly, bringing about a change in the rotational inertia of the entire rotor 2 system, thereby realizing energy storage and release.

[0036] By varying the moment of inertia of the flywheel rotor 2, the present invention allows for flexible and variable power output and input during the charge and discharge processes of the flywheel energy storage device, enabling instantaneous increases in charge capacity or decreases in discharge capacity. This flexible regulation allows for excellent matching of primary and secondary frequency modulation commands from the power grid. Furthermore, the present invention offers a simple structure, reduced investment costs, and higher returns.

[0037] Reference Figure 2-Figure 4 In some embodiments, the connecting member 4 includes a tension spring 41 , one end of the tension spring 41 is connected to the rotating shaft 3 , and the other end of the tension spring 41 is connected to the rotor 2 .

[0038] It should be noted that the rotor 2 and the rotating shaft 3 can be connected by the tension spring 41. At the same time, the tension spring 41 can also limit the motion trajectory of the rotor 2. Most importantly, by using the tension spring 41 to connect the rotor 2 and the rotating shaft 3, the rotor 2 can quickly and synchronously change the distance between the rotor 2 and the rotating shaft 3 according to the change in the rotation speed of the rotating shaft 3, thereby achieving the effect of stepless speed change, that is, the rotor 2 can sensitively change the mass distribution radius of the rotor 2 according to the change in the rotation speed of the rotating shaft 3, so that the moment of inertia changes synchronously, without any restrictions similar to gear positions.

[0039] Specifically, the bottom end of the rotor 2 contacts the end of the fixed disk 5 , and the bottom end of the fixed disk 5 is provided with a passive axial permanent magnet 6 .

[0040] Furthermore, an active axial permanent magnet 7 is provided on the bottom end face of the cavity 11, and a passive axial permanent magnet 6 is opposite to the active axial permanent magnet 7, and the magnetic poles of the passive axial permanent magnet 6 and the active axial permanent magnet 7 repel each other, thereby reducing the friction force when the fixed disk 5 rotates with the rotating shaft 3.

[0041] Furthermore, one end of the rotating shaft 3 is inserted into the cavity 11 from the end of the shell 1 along the central axis of the shell 1 and passes through the fixed disk 5 to be connected to the active axial permanent magnet 7; the other end of the rotating shaft 3 is connected to the reciprocal bidirectional motor 8.

[0042] It should be noted that the primary frequency modulation instructions of the power grid are small and fluctuate rapidly. The amount of electricity required for each frequency modulation is very small, but the required time is short. The frequency modulation time is generally 20 seconds, that is, the excess electricity needs to be consumed or replenished within 20 seconds. At low speeds, the centrifugal force on the rotor 2 decreases, causing the rotor 2 to move toward the shaft 3. At this time, the mass distribution radius of the rotor 2 decreases, resulting in a smaller moment of inertia. This allows it to well match the primary frequency modulation of the power grid (at low speeds, the charge and discharge amount is small, and the response time is the same as at high speeds).

[0043] The grid's secondary frequency modulation (AGC) instructions are large, and there is a high probability of continuous same-direction or reverse direction. The general frequency modulation time is 3 to 6 minutes, and the charge and discharge capacity at low speed cannot meet its requirements. When the grid's positive secondary frequency modulation instruction (charging instruction) is given to the flywheel energy storage device, the flywheel energy storage device needs to quickly absorb the electricity and store it in the flywheel rotor 2. Specifically, as the speed of the shaft 3 increases, the distance between the rotor 2 and the shaft 3 increases, resulting in a greater moment of inertia of the rotor 2. That is, the faster the speed of the shaft 3, the greater the stored electricity.

[0044] When the grid's reverse secondary frequency modulation instruction (discharge instruction) is given to the flywheel energy storage device, the flywheel energy storage device needs to quickly discharge to the grid. As the speed of the rotating shaft 3 decreases, the rotor 2 moves toward the rotating shaft 3. At this time, the mass distribution radius of the rotor 2 becomes smaller, which makes the moment of inertia smaller. At this time, the flywheel energy storage device quickly converts energy into electricity and releases it, realizing rapid replenishment of electricity.

[0045] Reference Figure 5 and Figure 6 As an optional embodiment, the connecting member 4 further includes a connecting shaft 42 , the connecting shaft 42 includes a first end and a second end, the first end is connected to the rotating shaft 3 , and the second end passes through the rotor 2 .

[0046] Specifically, the diameter of the first end of the connecting shaft 42 is smaller than the diameter of the second end; the second end passes through the rotor 2 and is connected to the limiting plate 43 .

[0047] Reference Figure 6 Furthermore, the rotor 2 is provided with a through hole 21 along the transverse center axis. The diameter of the through hole 21 is larger than the diameter of the second end portion, and the diameter of the through hole 21 is smaller than the diameter of the limit plate 43. The limit plate 43 is used to prevent the rotor 2 from being separated from the connecting shaft 42.

[0048] Furthermore, an accommodating cavity is provided on the inner wall of the rotor 2, which is communicated with the through hole 21; a return spring 22 is connected to the accommodating cavity, and a resistance block 23 is connected to the end of the return spring 22. An arc groove 24 is provided on the end of the resistance block 23 away from the return spring 22, and the arc groove 24 is adapted to the outer wall of the connecting shaft 42. The function of the return spring 22 is to ensure that the resistance block 23 is always in contact with the outer wall of the connecting shaft 42, and the function of the resistance block 23 and the spring is to prevent the rotor 2 from sliding freely along the connecting shaft 42. The rotor 2 can only overcome the contact force between the resistance block 23 and the outer wall of the connecting shaft 42 and move along the outer wall of the connecting shaft 42 when it is affected by changes in centrifugal force. When the centrifugal force does not change, the rotor 2 remains at the position of the outer wall of the connecting shaft 42 and does not move.

[0049] Different from the previous embodiment, as the rotation speed of the rotating shaft 3 changes, the centrifugal force applied to the rotor 2 changes, and the rotor 2 slides along the rotating shaft 3. When the rotation speed of the rotating shaft 3 increases, the centrifugal force applied to the rotor 2 increases. At this time, the rotor 2 slides along the first end of the connecting shaft 42 to the second end. When the rotor 2 slides along the first end of the connecting shaft 42 to the second end, since the diameter of the second end is larger than the first end, the resistance block 23 moves toward the accommodating cavity under the resistance force of the outer wall of the connecting shaft 42.

[0050] When the rotation speed of the rotating shaft 3 decreases, the centrifugal force on the rotor 2 decreases. At this time, the rotor 2 slides along the second end of the connecting shaft 42 toward the first end. When the rotor 2 slides along the second end of the connecting shaft 42 toward the first end, since the diameter of the second end is larger than the first end, the resistance block 23 moves toward the connecting shaft 42 under the elastic force of the return spring 22.

[0051] The remaining structure and working principle are the same as those of the previous embodiment.

[0052] Finally, it should be pointed out that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways without departing from the scope of the present invention.

Claims

1. A flywheel energy storage device, characterized in that: include, A housing (1) is provided, wherein a cavity is formed along the periphery of the inner wall of the housing (1) for accommodating the rotor (2), and the rotating shaft (3) is inserted into the bottom of the cavity from the outside of the housing (1) along the central axis of the housing (1); The rotors (2) are provided in at least two groups. The rotors (2) are arranged circumferentially with the rotating shaft (3) as the center. The rotors (2) can rotate simultaneously with the rotating shaft (3). When the rotors (2) rotate, the distance between the rotors (2) and the rotating shaft (3) can be changed according to the change of centrifugal force.

2. The flywheel energy storage device according to claim 1, characterized in that: The rotor (2) is connected to the rotating shaft (3) via a connecting member (4), and the connecting member (4) enables the rotor (2) to change the distance from the rotor (2) to the rotating shaft (3) by changing the rotation speed of the rotating shaft (3); The distance between the rotor (2) and the rotating shaft (3) is changed by changing the rotation speed of the rotating shaft (3), thereby changing the mass distribution radius of the rotor (2) and causing the moment of inertia to change synchronously.

3. The flywheel energy storage device according to claim 2, characterized in that: The connecting member (4) comprises a tension spring (41), one end of the tension spring (41) is connected to the rotating shaft (3), and one end of the tension spring (41) is connected to the rotor (2).

4. The flywheel energy storage device according to claim 2, characterized in that: The connecting member (4) further comprises a connecting shaft (42), wherein the connecting shaft (42) comprises a first end (421) and a second end (422), wherein the first end (421) is connected to the rotating shaft (3), and the second end (422) passes through the rotor (2).

5. The flywheel energy storage device according to claim 4, characterized in that: The diameter of the first end (421) of the connecting shaft (42) is smaller than the diameter of the second end (422); The second end (422) passes through the rotor (2) and is connected to the limiting plate (43).

6. The flywheel energy storage device according to claim 5, characterized in that: The rotor (2) is provided with a through hole (21) along the transverse central axis, the diameter of the through hole (21) is larger than the diameter of the second end (422), and the diameter of the through hole (21) is smaller than the diameter of the limiting plate (43).

7. The flywheel energy storage device according to claim 6, characterized in that: The inner wall of the rotor (2) is further provided with an accommodating cavity, and the accommodating cavity is communicated with the through hole (21); A return spring (22) is connected to the accommodating cavity, and a resistance block (23) is connected to the end of the return spring (22). An arc groove (24) is formed at one end of the resistance block (23) away from the return spring (22), and the arc groove (24) is adapted to the outer wall of the connecting shaft (42).

8. The flywheel energy storage device according to claim 3 or 7, characterized in that: The bottom end of the rotor (2) contacts the end of the fixed disk (5), and a passive axial permanent magnet (6) is provided at the bottom end of the fixed disk (5).

9. The flywheel energy storage device according to claim 8, characterized in that: An active axial permanent magnet (7) is provided on the bottom end surface of the cavity, and the passive axial permanent magnet (6) is opposite to the active axial permanent magnet (7).

10. The flywheel energy storage device according to claim 9, characterized in that: One end of the rotating shaft (3) is inserted into the cavity from the end of the shell (1) along the central axis of the shell (1) and passes through the fixed disk (5) to be connected to the active axial permanent magnet (7); The other end of the rotating shaft (3) is connected to a reciprocal bidirectional motor (8).

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