An ultra-high energy density superconducting flywheel energy storage system with additional centripetal force device

Abstract

The application belongs to the field of flywheel energy storage, and particularly relates to a super-high energy density superconducting flywheel energy storage system containing an additional centripetal force device, aiming at solving the problem that the flywheel rotation speed is limited by the strength of the material itself. The application comprises a vacuum cavity, a driving device, a flywheel, an additional centripetal force providing device and a high-temperature superconducting magnetic suspension bearing. The driving device is in transmission connection with the flywheel, and the additional centripetal force providing device is arranged outside the flywheel. The additional centripetal force providing device can provide additional centripetal force to the flywheel, so that the rotation speed of the flywheel can be higher than the limit rotation speed determined by the limit strength of the flywheel material itself, thereby breaking the problem that the flywheel rotation speed is limited by the material strength, and enabling the superconducting flywheel energy storage system to realize super-high energy density energy storage.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of flywheel energy storage, and particularly relates to a super-high energy storage density superconducting flywheel energy storage system containing an additional centripetal force device. BACKGROUND

[0002] Flywheel energy storage is a technology for storing energy by using a rotating flywheel, and has the advantages of high energy storage density, large power, high efficiency, long service life, no pollution, etc. However, when the flywheel rotor speed of the flywheel energy storage system reaches or approaches the limit speed of the flywheel material, the flywheel will be deformed or damaged due to excessive centrifugal force, making it difficult to further improve the capacity of the flywheel energy storage system.

[0003] Increasing the flywheel rotor speed is the key to improving the energy storage capacity of the flywheel energy storage system. However, when the flywheel rotates at high speed, a large centrifugal force will be generated. When the centrifugal force increases to the limit of the centripetal force that the flywheel material can provide, the flywheel will be deformed or damaged. How to reduce the deformation and damage of the flywheel during high-speed rotation to improve the energy storage capacity of the flywheel energy storage system has become a problem to be solved in the current flywheel energy storage technology field.

[0004] In theory, the strength of the flywheel material determines the size of the centripetal force that the flywheel can provide, and the limit (maximum) strength of the flywheel material determines the maximum speed that the flywheel can reach, i.e. the energy storage capacity or energy storage density of the flywheel energy storage system is limited by the limit strength of the flywheel material, and the higher the value, the greater the theoretical energy storage or energy storage density. For this reason, relevant institutions have carried out a lot of explorations on improving the strength of the flywheel material. For example, Chinese invention patent CN103867639A adopts a step-by-step winding and curing process and a tension decreasing winding process during the preparation of the flywheel, which solves the problem of low strength of the metal flywheel that cannot meet the high-speed rotation requirement of the flywheel. Chinese invention patent CN106369107A adds elements such as nickel, chromium, molybdenum, lanthanum, gadolinium and yttrium to the flywheel material to improve the strength of the flywheel material. Chinese invention patent CN105864358A uses carbon fiber composite material flywheel in the flywheel energy storage system, the flywheel is made of multiple layers of carbon fiber prepreg circles stacked at different angles, and is formed by molding and then machined, thereby improving the hoop tensile strength of the flywheel, preventing it from being damaged during high-speed rotation, and further improving the flywheel speed, thereby solving the problem of low strength of the metal flywheel that cannot rotate at high speed for energy storage.

[0005] In summary, the existing research and invention mostly use the development of higher strength composite materials to improve the limit (maximum) speed of the flywheel and the energy storage density of the flywheel energy storage system, but cannot break through the limit speed determined by the limit strength of the flywheel material itself, and cannot fundamentally solve the problem that the flywheel speed is limited by the strength of the material itself. SUMMARY

[0006] In order to solve the problem that the flywheel rotation speed is limited by the material strength in the prior art, the application provides an ultra-high energy storage density superconducting flywheel energy storage system with an additional centripetal force device, which comprises a vacuum cavity, a driving device, a flywheel, an additional centripetal force providing device and a high-temperature superconducting magnetic suspension bearing.

[0007] The driving device is in transmission connection with the flywheel, and the additional centripetal force providing device is arranged outside the flywheel.

[0008] The additional centripetal force providing device can provide an additional centripetal force to the flywheel.

[0009] According to some embodiments of the application, the additional centripetal force providing device of the ultra-high energy storage density superconducting flywheel energy storage system with the additional centripetal force device comprises a superconducting current-carrying layer and a magnet.

[0010] The superconducting current-carrying layer is coaxially arranged with the flywheel, the superconducting current-carrying layer is arranged in a ring shape to form a continuous ring structure, the magnet is located on both sides of the superconducting current-carrying layer in the axial direction, and the superconducting current-carrying layer is subjected to an ampere force in the magnetic field generated by the magnet, the ampere force is directed to the center of the flywheel, and the flywheel is subjected to a centripetal force.

[0011] According to some embodiments of the application, the superconducting current-carrying layer of the ultra-high energy storage density superconducting flywheel energy storage system with the additional centripetal force device is composed of a plurality of layers of superconducting tapes or superconducting films.

[0012] According to some embodiments of the application, the ultra-high energy storage density superconducting flywheel energy storage system with the additional centripetal force device further comprises a high-temperature superconducting magnetic suspension bearing, and the high-temperature superconducting magnetic suspension bearing is coaxially arranged with the flywheel.

[0013] According to some embodiments of the application, the high-temperature superconducting magnetic suspension bearing of the ultra-high energy storage density superconducting flywheel energy storage system with the additional centripetal force device comprises a rotor, and the rotor is jointly made of a permanent magnet (neodymium iron boron magnet or samarium cobalt magnet) and a magnetic ring.

[0014] According to some embodiments of the application, the high-temperature superconducting magnetic suspension bearing of the ultra-high energy storage density superconducting flywheel energy storage system with the additional centripetal force device further comprises a stator, and the stator is made of a high-temperature superconducting block (REBCO or MgB2 block).

[0015] According to some embodiments of the application, the REBCO high-temperature superconducting block is at least one of yttrium, neodymium, samarium, gadolinium or dysprosium, or the MgB2 block.

[0016] According to some embodiments of the present application, an ultra-high energy density superconducting flywheel energy storage system with an additional centripetal force device is provided, and the driving device is an electric motor.

[0017] The present application has the following advantages:

[0018] (1) By providing an additional centripetal force device, the problem of flywheel speed being limited by material strength is broken, so that the flywheel speed can be higher than the limit speed determined by the ultimate strength of the flywheel material itself, so that the superconducting flywheel energy storage system can achieve ultra-high energy density energy storage.

[0019] (2) The flywheel rotor can be provided with stable and reliable additional centripetal force to offset part of the centrifugal force during the operation of the flywheel rotor, improve the maximum speed of the flywheel rotor, and improve the energy storage capacity and energy storage density of the flywheel energy storage system.

[0020] (3) The flywheel can also be provided with self-stabilizing suspension force to improve the suspension stiffness, effectively solve the problem of relatively weak suspension stiffness of the superconducting bearing, and further improve the stability and reliability of the system. BRIEF DESCRIPTION OF DRAWINGS

[0021] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments made with reference to the accompanying drawings.

[0022] Figure 1 is a structural schematic diagram of some embodiments of the present application;

[0023] Figure 2 is a calculation case result graph without an additional centripetal force device, and the flywheel speed reaches the allowable stress at 5440 rpm;

[0024] Figure 3 is a calculation case result graph with an additional centripetal force device, and the flywheel speed reaches the allowable stress at 5730 rpm.

[0025] In the figure: 1, vacuum cavity; 2, electric motor; 3, flywheel; 4, additional centripetal force providing device; 41, superconducting current-carrying layer; 42, magnet; 5, high-temperature superconducting magnetic suspension bearing; 51, rotor; 52, stator. DETAILED DESCRIPTION

[0026] The present application will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the related application, and not to limit the application. In addition, it should be noted that, in order to facilitate description, only the parts related to the application are shown in the drawings.

[0027] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0028] As shown in Figure 1 The present application provides an ultra-high energy storage density superconducting flywheel energy storage system with additional centripetal force device, comprising a vacuum chamber 1, a driving device 2, a flywheel 3, an additional centripetal force providing device 4, and a high-temperature superconducting magnetic suspension bearing 5.

[0029] The driving device 2 is in transmission connection with the flywheel 3, and the additional centripetal force providing device 4 is arranged outside the flywheel 3.

[0030] The additional centripetal force providing device 4 can provide additional centripetal force to the flywheel 3.

[0031] In specific implementation, the vacuum chamber 1 provides a vacuum environment for the flywheel 3, the driving device is a motor 2, the motor 2 is located at the uppermost position inside the vacuum chamber 1, the motor 2 is a high-speed motor, the motor 2 drives the flywheel 3 to rotate, the additional centripetal force providing device 4 is arranged to provide stable and reliable additional centripetal force to the flywheel 3, to offset part of the centrifugal force in the operation process of the flywheel 3, to improve the maximum rotational speed of the flywheel 3, and to further improve the energy storage amount and energy storage density of the flywheel energy storage system.

[0032] In some implementations, the additional centripetal force providing device 4 comprises a superconducting current-carrying layer 41 and a magnet 42.

[0033] The superconducting current-carrying layer 41 is coaxially arranged with the flywheel 3, the superconducting current-carrying layer 41 is arranged in a ring shape to form a continuous surrounding structure, and a constant current can be generated by induction; the magnet 42 is located on both sides of the superconducting current-carrying layer 41 in the axial direction, and the superconducting current-carrying layer 41 is subjected to an ampere force in the magnetic field generated by the magnet 42, which points to the center of the flywheel 3, thereby exerting a centripetal force on the flywheel 3.

[0034] In specific implementation, the magnet 42 of the additional centripetal force providing device 4 is located on the upper and lower sides of the superconducting current-carrying layer 41 in the axial direction, a refrigeration means can be used to reduce the temperature of the high-temperature superconducting magnetic suspension bearing 5 and the flywheel 3 to below the critical temperature of the superconductor, so that they are in a superconducting state; the superconducting current-carrying layer 41 generates a constant current by induction excitation, and operates in a closed loop after excitation; the superconducting current-carrying layer 41 is located in the magnetic field generated by the magnet 42, so that the ampere force acting on it points to the center of the flywheel 3 in the radial direction, thereby providing additional centripetal force to the flywheel 3, as shown in Figure 1 The direction indicated by F in the figure is the direction of the additional centripetal force, and the additional centripetal force can offset part of the centrifugal force of the flywheel 3, thereby improving the limit speed of the flywheel 3, effectively solving the problem that the flywheel is difficult to break through the material limit speed in high-speed rotation in the prior art, thereby improving the energy storage density, stability and safety of the system.

[0035] In some embodiments, the superconducting current-carrying layer 41 is composed of a plurality of layers of superconducting tapes or superconducting films, and is arranged in a ring shape to form a continuous ring structure and is coaxially arranged with the flywheel 3.

[0036] In some embodiments, the high-temperature superconducting magnetic levitation bearing 5 is coaxially arranged with the flywheel 3.

[0037] In specific implementation, the high-temperature superconducting magnetic levitation bearing 5 is provided with two groups, as shown in the figure. Figure 1 The two groups of high-temperature superconducting magnetic levitation bearings 5 are respectively arranged on the upper and lower sides of the flywheel 3.

[0038] In some embodiments, the high-temperature superconducting magnetic levitation bearing 5 includes a rotor 51, which is made of a permanent magnet (neodymium iron boron magnet or samarium cobalt magnet) and a magnetic ring.

[0039] In specific implementation, the rotor 51 of the superconducting magnetic levitation bearing is made of a permanent magnet (neodymium iron boron magnet (NdFeB) or samarium cobalt magnet (SmCo)) and a magnetic ring, which is coaxial with the flywheel 3 in the high-temperature superconducting flywheel energy storage system and provides a magnetic field for the stator 52 to generate a stable levitation force.

[0040] In some embodiments, the high-temperature superconducting magnetic levitation bearing 5 further includes a stator 52, which is made of a high-temperature superconducting block (REBCO or MgB2 block).

[0041] In specific implementation, the stator 52 of the superconducting magnetic levitation bearing is made of a REBCO high-temperature superconducting block, which is one of yttrium (Y), neodymium (Nd), samarium (Sm), gadolinium (Gd), and dysprosium (Dy), and is fixed below the high-temperature superconducting flywheel energy storage system to provide a levitation force for the rotor 51.

[0042] The application covers the superconducting current-carrying layer 41 on the outer surface of the flywheel 3, uses the Ampere force of the current in the superconducting layer in the magnetic field to provide an additional centripetal force for the flywheel rotor, breaks through the limit of the flywheel material, and improves the capacity, energy storage density, and system safety and stability of the flywheel energy storage system.

[0043] As shown in the figure, taking a T700 carbon fiber material flywheel as an example, the calculation parameters are shown in the following table. Figures 2-3

[0044]

[0045]

[0046] ​The first step calculates the maximum speed of the flywheel without the additional centripetal force providing device, and the calculation result shows that the maximum speed of the flywheel is 5440 rpm under the limitation of the material strength of the flywheel (reaching the allowable stress). The stress distribution of the flywheel at the speed of 5440 rpm is shown in FIG. 1. Figure 2

[0047] The second step calculates the maximum speed of the flywheel with the additional centripetal force providing device providing a centripetal stress of 10 MPa, and the calculation result shows that the maximum speed of the flywheel is 5730 rpm under the limitation of the material strength of the flywheel (reaching the allowable stress). The stress distribution of the flywheel at the speed of 5730 rpm is shown in FIG. 2. Figure 3

[0048] In summary, in this case, the additional centripetal force providing device provides a centripetal stress of 10 MPa, and the maximum speed of the flywheel can be increased by 290 rpm, and the energy storage capacity is increased by 6%. At present, the additional centripetal force of 10 MPa can be easily realized. By optimizing the design of the additional centripetal force providing device, a higher additional centripetal force (such as 100 MP) can be provided, so as to greatly improve the energy storage capacity and the energy storage density of the system.

[0049] In the description of the present application, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicating the direction or positional relationship are based on the direction or positional relationship shown in the drawings, which is merely for the convenience of description, and does not indicate or imply that the device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0050] In addition, it should be noted that, in the description of the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements. Those skilled in the art can understand the specific meaning of the above terms in the present application according to the specific circumstances.

[0051] The term "comprising" or any other similar word is intended to cover non-exclusive inclusion, so that the process, method, article or equipment / device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or includes the elements inherent in the process, method, article or equipment / device.

[0052] ​​The technical scheme of the present application has been described in combination with the preferred embodiments shown in the drawings, but it is easily understood that the protection scope of the present application is obviously not limited to these specific embodiments. The skilled in the art can make equivalent changes or replacements to the related technical features without departing from the principles of the present application, and the technical schemes after these changes or replacements will be included in the protection scope of the present application.

Claims

1. A superconducting flywheel energy storage system with an additional centripetal force device, characterized in that, It includes a vacuum chamber (1), a drive unit (2), a flywheel (3), an additional centripetal force providing device (4), and a high-temperature superconducting magnetic levitation bearing (5); The drive device (2) is connected to the flywheel (3) in a transmission connection, and the additional centripetal force providing device (4) is disposed on the outside of the flywheel (3); The additional centripetal force providing device (4) is capable of providing additional centripetal force to the flywheel (3); The additional centripetal force providing device (4) includes a superconducting current-carrying layer (41) and a magnet (42). The superconducting current-carrying layer (41) is coaxially arranged with the flywheel (3). The superconducting current-carrying layer (41) is arranged in a ring to form a continuous surrounding structure. The magnet (42) is located on both sides of the axial direction of the superconducting current-carrying layer (41). The Ampere force on the superconducting current-carrying layer (41) in the magnetic field generated by the magnet (42) points towards the center of the flywheel (3) and applies a centripetal force to the flywheel (3).

2. The ultra-high energy density superconducting flywheel energy storage system with an additional centripetal force device according to claim 1, characterized in that, The superconducting current-carrying layer (41) is composed of multiple superconducting tapes or superconducting thin films.

3. The ultra-high energy density superconducting flywheel energy storage system with an additional centripetal force device according to claim 1, characterized in that, It also includes a high-temperature superconducting magnetic levitation bearing (5), which is coaxially arranged with the flywheel (3).

4. The ultra-high energy density superconducting flywheel energy storage system with an additional centripetal force device according to claim 3, characterized in that, The high-temperature superconducting magnetic levitation bearing (5) includes a rotor (51), which is made of a permanent magnet and a polymagnet ring.

5. The ultra-high energy density superconducting flywheel energy storage system with an additional centripetal force device according to claim 4, characterized in that, The high-temperature superconducting magnetic levitation bearing (5) also includes a stator (52), which is made of high-temperature superconducting bulk material.

6. The ultra-high energy density superconducting flywheel energy storage system with an additional centripetal force device according to claim 5, characterized in that, The high-temperature superconducting block is at least one of yttrium, neodymium, samarium, gadolinium or dysprosium, or magnesium diboride (MgB2) material.

7. The ultra-high energy density superconducting flywheel energy storage system with an additional centripetal force device according to claim 1, characterized in that, The driving device (2) is a motor.

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