Split-type flywheel energy storage device

Abstract

This invention discloses a split-type flywheel energy storage device, including a flywheel body, a motor assembly, and a mounting base. The motor assembly is detachably connected and fixed to the flywheel body via the mounting base. The combined structure of the motor assembly and the mounting base has a first chamber, and the flywheel body has a second chamber. The first and second chambers are isolated from each other. The motor shaft of the motor assembly extends towards the inner cavity of the mounting base, and the rotor shaft of the flywheel body extends out of the flywheel body and towards the inner cavity of the mounting base. The motor shaft and the rotor shaft are connected by a heat-insulated detachable connection. While effectively solving the problem of motor rotor heat dissipation, this invention also reduces the wind resistance loss of the motor rotor, resulting in a split-type flywheel energy storage device with higher cycle efficiency and more reliable long-term operational safety.

Description

Technical Field

[0001] This invention relates to the field of mechanical energy storage devices, and in particular, to a split-type flywheel energy storage device. Background Technology

[0002] Flywheel energy storage systems are electromechanical energy conversion devices. The basic principle of flywheel energy storage is the conversion between electrical energy and the kinetic energy of a rotating body: during the energy storage phase, an electric motor drives the flywheel to accelerate, converting electrical energy into mechanical energy; during the energy release phase, the electric motor operates as a generator, while the flywheel motor decelerates, converting mechanical energy back into electrical energy for output. Flywheel energy storage systems are mechanical energy storage systems with broad application prospects, possessing advantages such as high energy density, strong adaptability, wide application range, high efficiency, long lifespan, no pollution, and low maintenance costs.

[0003] In related technologies, one way to achieve the transmission between the motor and the flywheel rotor is to adopt an integrated structure for the flywheel rotor and the motor rotor. The flywheel rotor and the motor rotor are manufactured as a whole or directly mechanically connected as a whole and placed in the same high vacuum environment. The heat loss of the motor rotor is transferred to the entire flywheel rotor, and its heat dissipation is a difficult point, which affects the long-term operational safety of the flywheel energy storage system. Another approach is to use magnetic couplings. Chinese patent application No. 200910242392.1 discloses a high-temperature superconducting flywheel with thermally isolated connection, which uses disc-type and cylindrical magnetic couplings to isolate the heat transfer between the motor rotor and the flywheel rotor, solving the problem of heat dissipation of the flywheel rotor and its impact on the high-temperature superconducting magnetic bearing. However, in this patented technical solution, the motor rotor and the flywheel rotor are located in the same vacuum chamber, and the heat dissipation problem of the motor rotor is not solved. Chinese patent application No. 202310827213.0 discloses an energy storage flywheel and energy storage device, which introduces a magnetic coupling assembly to realize non-contact transmission between the motor and the flywheel rotor. The motor is placed in the atmospheric environment, which solves the problem of heat insulation between the motor and the flywheel rotor and the heat dissipation of the motor rotor itself. However, in order to achieve vacuum sealing of the flywheel rotor cavity, a partition is set between the magnetic coupling assemblies, which brings eddy current losses. Moreover, the wind resistance loss of the motor rotor in the atmospheric environment is large, which affects the circulation efficiency of the flywheel energy storage system. Summary of the Invention

[0004] This invention provides a split-type flywheel energy storage device to solve the technical problems of difficult heat dissipation of the flywheel and motor rotor in flywheel energy storage systems and the impact on the cycle efficiency of flywheel energy storage systems.

[0005] This invention provides a split-type flywheel energy storage device, including a flywheel body, a motor assembly, and a mounting base. The motor assembly is detachably connected and fixed to the flywheel body via the mounting base. The combined structure of the motor assembly and the mounting base has a first chamber, and the flywheel body has a second chamber. The first chamber and the second chamber are isolated from each other. The motor shaft of the motor assembly extends toward the inner cavity of the mounting base, and the rotor main shaft of the flywheel body extends out of the flywheel body and toward the inner cavity of the mounting base. The motor shaft and the rotor main shaft are detachably connected with thermal insulation.

[0006] Furthermore, the flywheel body, motor assembly, and mounting base are manufactured separately and then assembled to form a complete device.

[0007] Furthermore, the motor shaft and the rotor main shaft are detachably connected by a heat-insulated coupling; or the motor shaft and the rotor main shaft are coaxially arranged, and a heat insulation layer is provided between the motor shaft and the rotor main shaft and a detachable fixed connector is used for connection; or the connecting end of the motor shaft and / or the connecting end of the rotor main shaft has a heat-insulating coating, and the motor shaft and the rotor main shaft are connected by a coupling.

[0008] Furthermore, the mounting base includes an upper boss, a lower boss, and a boss connecting part. The upper boss and the lower boss are both circular rings of equal thickness, and the upper boss and the lower boss are arranged coaxially. The boss connecting part connects the upper boss and the lower boss into a whole to enhance rigidity and ensure the coaxiality of the upper boss and the lower boss.

[0009] Furthermore, the inner diameter of the lower boss is larger than the inner diameter of the upper boss.

[0010] Furthermore, the upper boss, lower boss, and boss connection part are all integral plate structures. The upper boss is sealed and fixedly connected to the motor assembly, and the lower boss is sealed and fixedly connected to the flywheel body. The mounting base and the motor assembly enclose the first chamber, which is a sealed space, so that the first chamber can be maintained in a medium-low vacuum environment that is conducive to the operation of the motor assembly. Then, the motor rotor of the motor assembly drives the airflow to effectively dissipate heat from the motor rotor and reduce the wind resistance loss of the motor rotor.

[0011] Furthermore, the boss connection part adopts a hollow spoke structure so that the first chamber can be connected to the atmosphere through the hollow gap, and then the motor rotor of the motor assembly drives the air flow so that the first chamber can fully exchange heat with the atmosphere to achieve heat dissipation.

[0012] Furthermore, the flywheel body includes a flywheel housing and a flywheel rotor disposed within the flywheel housing; the flywheel rotor includes a rotor spindle, a first rotor section disposed radially on the rotor spindle, and a second rotor section located on the outer periphery of the first rotor section. The first rotor section, the second rotor section, and the rotor spindle are manufactured separately and then assembled into a whole by temperature interference fit.

[0013] Furthermore, at least two sets of axial magnetic bearings for active magnetic levitation control of the flywheel rotor are provided between the flywheel housing and the flywheel rotor. The axial magnetic bearings are all located on the side of the flywheel rotor opposite to the direction of gravity, and the two adjacent sets of axial magnetic bearings are arranged at intervals in the radial direction of the flywheel rotor.

[0014] Furthermore, the part of the flywheel body where the rotor shaft extends is provided with a magnetic fluid rotary seal structure for cooperating with the rotor shaft dynamic seal to isolate the first chamber from the second chamber.

[0015] The present invention has the following beneficial effects:

[0016] 1. The present invention relates to a split-type flywheel energy storage device, wherein the flywheel body and the motor assembly adopt a separate structure. The flywheel rotor of the flywheel body and the motor rotor of the motor assembly are respectively placed in different chambers. Specifically, the flywheel rotor is placed in the second chamber, and the motor rotor is placed in the first chamber. The motor shaft and the rotor main shaft are coaxially connected and adopt a heat-insulated detachable connection, which isolates the heat conduction of the motor rotor to the flywheel rotor. The second chamber where the flywheel rotor is located can maintain a high vacuum operating environment, which fundamentally solves the problem of heat dissipation of high-speed flywheel rotor and significantly reduces wind resistance loss. The first chamber where the motor rotor is located can maintain a suitable medium to low vacuum degree. While effectively solving the heat dissipation problem of the motor rotor, it also takes into account reducing the wind resistance loss of the motor rotor. This makes the split-type flywheel energy storage device of the present invention have higher cycle efficiency and more reliable long-term operational safety.

[0017] 2. The split-type flywheel energy storage device of the present invention has a motor assembly connected to the flywheel body via a mounting base. The mounting base allows for fine-tuning to ensure coaxiality between the motor shaft of the motor assembly and the flywheel rotor of the flywheel body, correcting minor deviations caused by manufacturing and assembly processes. The motor shaft of the motor assembly and the flywheel rotor of the flywheel body are connected within the inner cavity of the mounting base. This inner cavity serves as a transition space and also provides some degree of heat dissipation, effectively preventing heat conduction from the motor rotor to the flywheel rotor. Optionally, the mounting base can incorporate various heat dissipation methods, such as ventilation holes, water cooling, oil cooling, a cooling fan, or heat dissipation fins.

[0018] 3. The split-type flywheel energy storage device of the present invention allows for modular assembly and use of the flywheel body and motor assembly, providing users with flexibility in product selection and effectively reducing the development costs of serialized products. Specifically, various types, models, and functions of motor assemblies and flywheel bodies can be arbitrarily combined according to usage needs, functional requirements, and cost considerations, improving the adaptability and application flexibility of the split-type flywheel energy storage device.

[0019] 4. The split-type flywheel energy storage device of the present invention has a flywheel rotor that can be disassembled into three parts, which facilitates the manufacturing of rotor parts with different materials and different process requirements. It provides a flywheel rotor structure and its supporting bearing system suitable for large mechanical inertia, and can be applied to flywheel energy storage devices with ultra-large inertia, ultra-large capacity and ultra-high power.

[0020] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0021] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0022] Figure 1 This is a schematic diagram of the structure of a split-type flywheel energy storage device according to a preferred embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the structure of an axial magnetic bearing according to a preferred embodiment of the present invention;

[0024] Figure 3 This is one of the structural schematic diagrams of the magnetic liquid rotary sealing structure of a preferred embodiment of the present invention;

[0025] Figure 4 This is a second schematic diagram of the magnetic liquid rotary sealing structure according to a preferred embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram of the mounting base according to a preferred embodiment of the present invention.

[0027] Legend:

[0028] 1. Flywheel body; 101. Flywheel housing; 1011. Base; 1012. Top cover; 1013. Housing; 1014. Through hole; 1015. Blind hole; 102. Flywheel rotor; 1021. Rotor main shaft; 1022. First rotor section; 1023. Second rotor section; 2. Motor assembly; 201. Motor shaft; 202. Motor housing; 203. Motor rotor; 204. Motor stator; 205. Lower motor bearing; 206. Upper motor bearing; 207. Motor mounting boss; 3. Mounting base; 301. Upper boss; 302. Lower... 303. Boss; 4. First chamber; 5. Second chamber; 6. Magnetic fluid rotary sealing structure; 601. First pole shoe; 602. Permanent magnet; 603. Second pole shoe; 604. Sealing gap; 7. Coupling; 701. Primary coupling; 702. Secondary coupling; 8. First axial magnetic bearing; 801. Iron core; 802. Coil; 803. First air gap; 9. Second axial magnetic bearing; 901. Magnetic yoke; 902. Permanent magnet; 903. Second air gap; 10. First radial bearing; 11. Second radial bearing. Detailed Implementation

[0029] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0030] Figure 1 This is a schematic diagram of the structure of a split-type flywheel energy storage device according to a preferred embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of an axial magnetic bearing according to a preferred embodiment of the present invention; Figure 3 This is one of the structural schematic diagrams of the magnetic liquid rotary sealing structure of a preferred embodiment of the present invention; Figure 4 This is a second schematic diagram of the magnetic liquid rotary sealing structure according to a preferred embodiment of the present invention; Figure 5 This is a schematic diagram of the mounting base according to a preferred embodiment of the present invention.

[0031] like Figure 1As shown, the split-type flywheel energy storage device of this embodiment includes a flywheel body 1, a motor assembly 2, and a mounting base 3. The motor assembly 2 is detachably connected and fixed to the flywheel body 1 via the mounting base 3. The combined structure of the motor assembly 2 and the mounting base 3 has a first chamber 4, and the flywheel body 1 has a second chamber 5. The first chamber 4 and the second chamber 5 are isolated from each other. The motor shaft 201 of the motor assembly 2 extends toward the inner cavity of the mounting base 3. The rotor main shaft 1021 of the flywheel body 1 extends out of the flywheel body 1 and toward the inner cavity of the mounting base 3. The motor shaft 201 and the rotor main shaft 1021 are detachably connected with thermal insulation. This invention relates to a split-type flywheel energy storage device, in which the flywheel body 1 and the motor assembly 2 are separate structures. The flywheel rotor 102 of the flywheel body 1 and the motor rotor 203 of the motor assembly 2 are respectively placed in different chambers. Specifically, the flywheel rotor 102 is placed in the second chamber 5, and the motor rotor 203 is placed in the first chamber 4. The motor shaft 201 and the rotor main shaft 1021 are coaxially connected and use a heat-insulated detachable connection, which isolates the heat conduction of the motor rotor 203 to the flywheel rotor 102. The second chamber 5, where the flywheel rotor 102 is located, can maintain a high vacuum operating environment, which fundamentally solves the problem of heat dissipation of the high-speed flywheel rotor 102 and significantly reduces wind resistance loss. The first chamber 4, where the motor rotor 203 is located, can maintain a suitable medium to low vacuum degree. While effectively solving the heat dissipation problem of the motor rotor 203, it also takes into account the reduction of wind resistance loss of the motor rotor 203. This makes the split-type flywheel energy storage device of this invention have higher cycle efficiency and more reliable long-term operational safety. The present invention relates to a split-type flywheel energy storage device. The motor assembly 2 is connected to the flywheel body 1 via a mounting base 3. The mounting base 3 allows for fine-tuning to ensure coaxiality between the motor shaft 201 of the motor assembly 2 and the flywheel rotor 102 of the flywheel body 1, correcting minor deviations caused by manufacturing and assembly processes. The motor shaft 201 of the motor assembly 2 and the flywheel rotor 102 of the flywheel body 1 are connected within the cavity of the mounting base 3. This cavity serves as a transition space and also provides some degree of heat dissipation, effectively preventing heat conduction from the motor rotor 203 to the flywheel rotor 102. Optionally, the mounting base 3 can be configured with various heat dissipation methods, such as ventilation holes, water cooling, oil cooling, a cooling fan, or heat dissipation fins. The split-type flywheel energy storage device of the present invention allows for modular assembly and use of the flywheel body 1 and motor assembly 2, providing users with flexibility in product selection and effectively reducing the development costs of serialized products. Specifically, various types, models, and functions of motor components 2 can be selected and arbitrarily combined with the flywheel body 1 according to usage needs, functional requirements, and cost considerations, thereby improving the adaptability and application flexibility of the split-type flywheel energy storage device.

[0032] Furthermore, to address the dynamic sealing issue during rotor rotation between the first chamber 4 and the second chamber 5, a magnetic fluid rotary seal structure 6 is provided above the first radial bearing 10 within the through hole 1014. Its stationary portion includes a first pole shoe 601, a second pole shoe 603, and a permanent magnet 602. The outer diameters of the first pole shoe 601 and the second pole shoe 603 are identical, while the outer diameter of the permanent magnet 602 is less than or equal to the outer diameters of the first pole shoe 601 and the second pole shoe 603. The inner diameter of the permanent magnet 602 is greater than the inner diameters of the first pole shoe 601 and the second pole shoe 603. The first pole shoe 601, the second pole shoe 603, and the permanent magnet 602 are connected to form a single integrated structure. The outer circumferential surface of the magnetic fluid rotary seal structure 6 is connected to the inner circumferential surface of the through hole 1014, and the upper part of the rotor main shaft 1021 passes through the inner hole of the magnetic fluid rotary seal structure 6. A sealing gap 604 is provided between the inner circumferential surface of the magnetic fluid rotary seal structure 6 and the outer circumferential surface of the rotor main shaft 1021. The magnetomotive force of the permanent magnet 602 generates magnetic flux in the sealing gap 604. Magnetic fluid, which is oil-based or ester-based, is injected into the sealing gap 604. Under the action of the magnetic field, the magnetic fluid forms several liquid "O" rings in the gap between the shaft and the pole teeth of the pole shoes, achieving dynamic sealing. To ensure normal operation when the radial bearing is a magnetic bearing, the sealing gap 604 must be larger than the protective gap. However, increasing the sealing gap 604 will affect the sealing effect. Therefore, the radial length of the sealing gap 604 is 0.05mm to 0.7mm to ensure normal operation when the radial bearing on the rotor main shaft 1021 is a magnetic bearing. Optionally, the radial bearing on the rotor main shaft 1021 is arranged on the side of the magnetic fluid rotary seal structure 6 away from the motor housing 202.

[0033] In some embodiments, such as Figure 3 As shown, the magnetic fluid rotary seal structure 6 adopts a divergent stepped seal structure. The inner diameter of the first pole shoe 601 is smaller than the inner diameter of the second pole shoe 603. The leakage direction of the sealed medium is along the direction of increasing shaft diameter. The advantage is that multiple axial sealing gaps and radial sealing gaps are formed between the stepped shaft (rotor main shaft 1021) and the first pole shoe 601 and the second pole shoe 603. Under the action of an external magnetic field, the magnetic fluid can play a sealing role in both types of sealing gaps, thereby increasing the total sealing pressure resistance. It is suitable for situations with large sealing gaps.

[0034] In some embodiments, such as Figure 4 As shown, the magnetic liquid rotary sealing structure 6 adopts a non-stepped sealing structure. The inner diameter of the first pole shoe 601 is equal to the inner diameter of the second pole shoe 603. Its characteristics are simple structure and suitable for situations with small sealing gaps.

[0035] like Figure 1 and Figure 5As shown, in this embodiment, the flywheel body 1, motor assembly 2, and mounting base 3 are manufactured separately and assembled to form a complete device. Different types, models, and functions of the flywheel body 1, motor assembly 2, and mounting base 3 can be selected based on usage needs, functional requirements, cost considerations, and other factors. Optionally, when selecting a high-power, large-scale motor assembly 2, a mounting base 3 and flywheel body 1 with corresponding load-bearing capacity must be selected. The mounting base 3 is equipped with corresponding reinforcing ribs, support plates, and other reinforcing structures, and the flywheel housing 101 of the flywheel body 1 is also correspondingly reinforced with reinforcing ribs, support plates, and other reinforcing structures. Optionally, when the motor assembly 2 generates significant heat during operation, a mounting base 3 with relatively large internal space can be selected, and a water-cooling system, oil-cooling system, or blower system can be installed in the inner cavity of the mounting base 3. Optionally, when the motor assembly is prone to vibration during operation, a mounting base 3 with vibration damping function can be selected. The connection between the mounting base 3 and the motor assembly 2 or flywheel body 1 can also be equipped with sound-insulating pads, vibration-damping pads, dampers, etc., for vibration reduction and noise reduction.

[0036] like Figure 1 As shown, in this embodiment, the motor shaft 201 and the rotor main shaft 1021 are detachably connected by a heat-insulated coupling; or the motor shaft 201 and the rotor main shaft 1021 are coaxially arranged, and a heat insulation layer is provided between the motor shaft 201 and the rotor main shaft 1021 and a detachable fixed connector is used for connection; or the connecting end of the motor shaft 201 and / or the connecting end of the rotor main shaft 1021 has a heat-insulating coating, and the motor shaft 201 and the rotor main shaft 1021 are connected by a coupling. Optionally, the heat-insulated coupling is a mechanical heat-insulated coupling or a magnetic heat-insulated coupling. Optionally, the coupling 7 includes a coupling primary 701 and a coupling secondary 702, the coupling primary 701 is connected to the motor shaft 201, and the coupling secondary 702 is connected to the rotor main shaft 1021. Optionally, coupling 7 is a mechanical coupling, with a non-metallic material layer, such as an insulating ceramic layer, providing good thermal insulation between the primary coupling 701 and the secondary coupling 702. This ensures good thermal insulation between the motor shaft 201 and the rotor main shaft 1021, thereby guaranteeing the long-term safe and reliable operation of the split-type flywheel energy storage device. Optionally, coupling 7 is a magnetic coupling, enabling non-contact torque transmission between the motor shaft 201 and the rotor main shaft 1021, isolating the heat conduction from the motor rotor 203 to the flywheel rotor 102, thus fully guaranteeing the long-term safe and reliable operation of the split-type flywheel energy storage device. Because coupling 7 effectively isolates the heat transfer from the motor rotor 203 to the flywheel rotor 102, the second chamber 5 within the flywheel body 1 can be maintained in a high vacuum environment, significantly reducing the wind resistance loss of the flywheel rotor 102 and improving the circulation efficiency of the energy storage flywheel in the split-type flywheel energy storage device.

[0037] like Figure 1 and Figure 5 As shown, in this embodiment, the mounting base 3 includes an upper boss 301, a lower boss 302, and a boss connecting part 303. Both the upper boss 301 and the lower boss 302 are circular rings of equal thickness, and are coaxially arranged. The boss connecting part 303 connects the upper boss 301 and the lower boss 302 into a whole to enhance rigidity and ensure the coaxiality of the upper boss 301 and the lower boss 302. The upper boss 301 serves as a fixed mounting position for the motor assembly 2; the lower boss 302 serves as a mounting base 3 stably mounted on the flywheel body 1, providing an assembly position. Optionally, the mounting base 3 is mounted on the upper cover 1012 of the flywheel housing 101, coaxial with the through hole 1014, and the lower boss 302 is connected to the upper cover 1012 of the flywheel housing 101 using screws.

[0038] like Figure 1 As shown, in this embodiment, the motor assembly 2 includes a motor housing 202, a motor rotor 203, a motor shaft 201, a motor stator 204, a lower motor bearing 205, an upper motor bearing 206, and a motor mounting boss 207. The motor stator 204 is connected to the motor housing 202, and the motor mounting boss 207 is an integral structure with the motor housing 202, with the outer circle of the motor mounting boss 207 coaxial with the inner circle of the motor housing 202. In some embodiments, the motor assembly 2 is a permanent magnet synchronous motor, using existing technology, which will not be described in detail here. In some embodiments, the motor assembly 2 is an electrically excited synchronous motor, using existing technology, which will not be described in detail here. Optionally, the motor assembly 2 is mounted on a mounting base 3, with the motor mounting boss 207 coaxial with the upper boss 301 of the mounting base 3 and connected by a flange. The space enclosed by the motor housing 202 and the mounting base 3 forms a first chamber 4, and the first chamber 4 and the second chamber 5 are sealed and separated by a magnetic fluid rotary sealing structure 6. By adopting this technical solution, the design and manufacturing of the motor assembly 2 are independent of the flywheel body 1, and even a rack-mounted motor can be used, realizing the modular assembly and use of the flywheel body 1 and the motor assembly 2, which can effectively reduce the R&D cost of serialized products.

[0039] like Figure 1 and Figure 5As shown, in this embodiment, the inner diameter of the lower boss 302 is larger than the inner diameter of the upper boss 301, forming a frustum-shaped support structure to improve the overall support capacity. On the other hand, it allows the relatively small radial dimension of the motor assembly 2 to be organically connected with the larger radial dimension of the flywheel body 1, while also providing assembly space for the coaxial installation of the motor shaft 201 and the flywheel rotor 102, maximizing space utilization while improving aesthetics. Furthermore, the inner cavity of the frustum-shaped mounting base 3 forms an flared space between the motor assembly 2 and the flywheel body 1. This flared, gradually changing space can improve the heat dissipation capacity of the motor rotor 203 to the flywheel rotor 102 to a certain extent, effectively slowing down or even preventing heat conduction from the motor rotor 203 to the flywheel rotor 102.

[0040] like Figure 1 and Figure 5 As shown, in this embodiment, the upper boss 301, the lower boss 302, and the boss connecting part 303 are all integral plate structures. The upper boss 301 is sealed and fixedly connected to the motor assembly 2, and the lower boss 302 is sealed and fixedly connected to the flywheel body 1. The mounting base 3 and the motor assembly 2 enclose the first chamber 4, which is a sealed space so that the first chamber 4 can be maintained in a medium-low vacuum environment that is conducive to the operation of the motor assembly 2. Then, the motor rotor 203 of the motor assembly 2 drives the airflow to effectively dissipate heat from the motor rotor 203 and reduce the wind resistance loss of the motor rotor 203.

[0041] like Figure 1 and Figure 5 As shown, in this embodiment, the boss connection part 303 adopts a hollow spoke structure so that the first chamber 4 can be connected to the atmosphere through the hollow gap, and then the motor rotor 203 of the motor assembly 2 drives the air flow so that the first chamber 4 can fully exchange heat with the atmosphere to achieve heat dissipation.

[0042] like Figure 1 and Figure 5 As shown, in this embodiment, the boss connection part 303 adopts a rotating body structure, and the first chamber 4 is a sealed space, which is maintained at a suitable low vacuum level, so that the flowing air driven by the motor rotor 203 can effectively dissipate heat from the motor rotor 203. Under the premise of keeping the temperature rise of the motor rotor 203 within the safe operating range, the wind resistance loss of the motor rotor 203 is effectively reduced.

[0043] In this embodiment, at least two sets of axial magnetic bearings for active magnetic levitation control of the flywheel rotor 102 are provided between the flywheel housing 101 and the flywheel rotor 102. The axial magnetic bearings are all located on the side of the flywheel rotor 102 opposite to the direction of gravity, and the two adjacent sets of axial magnetic bearings are arranged at intervals in the radial direction of the flywheel rotor 102. Based on the flywheel rotor 102 being rotatably mounted on the upper cover 1012 and the base 1011, at least two sets of axial magnetic bearings are arranged at intervals between the flywheel rotor 102 and the upper cover 1012. One set of axial magnetic bearings is an electromagnetic attraction magnetic bearing, and the other set of axial magnetic bearings is a permanent magnet attraction magnetic bearing. The axial magnetic bearings work together to achieve gravity support for the flywheel rotor 102 through active magnetic levitation control. The axial magnetic bearings are all located on one side of the flywheel rotor 102, preferably on the side opposite to the direction of gravity of the flywheel rotor 102, and are arranged at intervals along the radial direction of the flywheel rotor 102. The axial magnetic bearings have a synergistic effect on each other, and the relative force is only the gravity of the flywheel rotor 102, thereby achieving the balance and stability of the flywheel rotor 102 with low power consumption. Specifically, at least two sets of axial magnetic bearings create multi-point upward magnetic attraction on the flywheel rotor 102. Combined with the flywheel rotor 102's own weight, this achieves active axial magnetic levitation control of the flywheel rotor 102, thus providing stable support for it. Compared to a single electromagnetic bearing, or two sets of electromagnetic bearings arranged vertically opposite each other, this invention's structure can achieve active axial magnetic levitation control of the flywheel rotor 102 with a relatively small control current, significantly reducing its levitation control power consumption. Furthermore, the synergistic effect of multiple sets of axial magnetic bearings also restricts the vertical swing of the flywheel rotor 102, promoting smooth rotation and effectively preventing the flywheel rotor 102 from becoming unstable and falling. This invention is particularly suitable for use with heavy-duty flywheel rotors 102. Optionally, two, three, four, or five sets of axial magnetic bearings are arranged, including at least one set of electromagnetic suction bearings and one set of permanent magnet suction bearings. By adding axial magnetic bearings, magnetic levitation enhancement control is achieved while dispersing the gravity of the flywheel rotor 102, which can reduce the levitation control power consumption to a certain extent. However, the number of axial magnetic bearings is not necessarily better the more there are. When the number of axial magnetic bearings exceeds the upper limit, they will interfere with each other, leading to an increase in levitation control power consumption. Optionally, the axial magnetic bearings are arranged close to the outer edge of the flywheel rotor 102. Optionally, the minimum spacing between two adjacent sets of axial magnetic bearings is determined so that their respective magnetic circuits do not interfere with each other.

[0044] In this embodiment, the flywheel body 1 includes a flywheel housing 101 and a flywheel rotor 102 disposed within the flywheel housing 101. The flywheel rotor 102 includes a rotor main shaft 1021, a first rotor section 1022 radially disposed on the rotor main shaft 1021, and a second rotor section 1023 located on the outer periphery of the first rotor section 1022. The first rotor section 1022, the second rotor section 1023, and the rotor main shaft 1021 are manufactured separately and then assembled into a whole by temperature interference fitting. The flywheel rotor 102 can be disassembled into three parts, which facilitates the manufacturing of rotor sections with different materials and process requirements. This provides a flywheel rotor 102 structure and its supporting bearing system suitable for large mechanical inertia, which can be applied to flywheel energy storage devices with ultra-large inertia, ultra-large capacity, and ultra-high power. The main body of the flywheel rotor 102 is located in the second chamber 5. The upper end of the rotor main shaft 1021 extends out of the upper end face of the upper cover 1012 of the flywheel housing 101. The motor rotor 203 is located in the first chamber 4. The lower end of the motor shaft 201 extends out of the lower end face of the motor housing 202. Optionally, the flywheel body 1 includes a flywheel housing 101, a flywheel rotor 102, a first axial magnetic bearing 8, a second axial magnetic bearing 9, a first radial bearing 10, a second radial bearing 11, and a magnetic fluid rotary sealing structure 6. Further, the flywheel housing 101 includes a base 1011, an upper cover 1012, and a housing 1013, which are connected as a whole, and the space enclosed by them forms the second chamber 5. A blind hole 1015 is opened from top to bottom at the center of the base 1011. A through hole 1014 is opened in the upper cover 1012, which is coaxial with the blind hole 1015. Optionally, the second rotor section 1023, located on the outermost side of the flywheel rotor 102, is a uniform cross-section annular body made of high-strength alloy material, such as 30Cr2MnMoNi2, or made of carbon fiber composite material wound, such as T700 or T800 carbon fiber wound. The first rotor section 1022, connecting the rotor main shaft 1021 and the second rotor section 1023, is also a uniform cross-section annular body made of high-strength alloy steel with good magnetic permeability, such as S06 steel, so that it can provide a magnetically conductive rotor body for the first axial magnetic bearing 8 and the second axial magnetic bearing 9. The rotor main shaft 1021, also made of high-strength alloy steel with good magnetic permeability, such as S06 steel, can provide a rotor magnetic conductor for the magnetic fluid rotary seal structure 6. The thickness of the second rotor section 1023 is greater than that of the first rotor section 1022, providing the main part of the mechanical rotational inertia of the flywheel rotor 102 about the main shaft. In some embodiments, the first rotor section 1022, the second rotor section 1023, and the rotor main shaft 1021 are manufactured separately and then assembled into a whole by temperature interference fitting. In some embodiments, in order to further increase the rim speed of the flywheel rotor 102, thereby increasing the energy storage capacity and specific energy density of the flywheel energy storage device, the inner lining of the first rotor section 1022 is made of high-strength alloy material, and the outer layer is wound with carbon fiber composite material.

[0045] Furthermore, to effectively address the issue of low-loss stable support in the direction of gravity for heavy rotors, a first axial magnetic bearing 8 and a second axial magnetic bearing 9 are adjacently arranged between the lower end face of the upper cover 1012 and the upper end face of the first rotor section 1022. The first axial magnetic bearing 8 is an electromagnetic attraction bearing, bearing 10% to 20% of the gravity of the flywheel rotor 102, and the second axial magnetic bearing 9 is a permanent magnet attraction bearing, bearing 80% to 90% of the gravity of the flywheel rotor 102. Under the controllable upward attraction of the first axial magnetic bearing 8 on the flywheel rotor 102, the upward attraction of the second axial magnetic bearing 9 on the flywheel rotor 102, and the gravity of the flywheel rotor 102, axial active magnetic levitation control of the flywheel rotor 102 is achieved. Since the second axial magnetic bearing 9 bears most of the weight of the flywheel rotor 102, and the first axial magnetic bearing 8 only bears a small portion of the weight of the flywheel rotor 102, compared with the technical solution that only uses a single electromagnetic bearing, the technical solution of the present invention achieves axial active magnetic levitation control of the flywheel rotor 102 with a smaller control current, thereby significantly reducing its levitation control power consumption.

[0046] In some embodiments, the first axial magnetic bearing 8 is located on the outer side, and its stationary part includes an iron core 801 and a coil 802. The iron core 801 is made of a metal material with good magnetic permeability, such as No. 10 steel. A circular groove is opened in the middle of its lower part, and magnetic poles are provided on both sides of the groove. The coil 802 is embedded in the circular groove of the iron core 801 and fixed by epoxy resin potting. The upper end face of the iron core 801 of the first axial magnetic bearing 8 is connected to the lower end face of the upper cover 1012. The iron core 801 of the first axial magnetic bearing 8 is connected to the upper cover 1012 with screws. The rotor magnetic conductor of the first axial magnetic bearing 8 is integrally manufactured with the first rotor part 1022. A first air gap 803 is provided between the magnetic pole surface of the first axial magnetic bearing 8 and the upper end face of the first rotor part 1022. When the coil 802 is energized with a control current, it generates an electromagnetic magnetomotive force, which generates a controllable magnetic flux in the first air gap 803, forming an upward controllable attraction force on the flywheel rotor 102.

[0047] In some embodiments, the second axial magnetic bearing 9 is located on the inner edge, and its stationary portion includes a permanent magnet 902 and a yoke 901. The yoke 901 is made of a metal material with good magnetic permeability, such as No. 10 steel, and has an annular groove in the middle of its lower part, with magnetic poles on both sides of the groove. The permanent magnet 902 is a ring-shaped body, axially magnetized, and is segmented and embedded in the annular groove of the yoke 901. The lower end face of the permanent magnet 902 is on the same plane as the magnetic pole face of the yoke 901. The upper end face of the yoke 901 is connected to the lower end face of the upper cover 1012, and the yoke 901 of the second axial magnetic bearing 9 is connected to the upper cover 1012 with screws. The rotor magnetic conductor of the second axial magnetic bearing 9 is integrally manufactured with the first rotor part 1022. A second air gap 903 is provided between the lower end face of the second axial magnetic bearing 9 and the upper end face of the first rotor section 1022. The magnetomotive force of the permanent magnet 902 generates magnetic flux in the second air gap 903, forming an upward attraction force on the flywheel rotor 102. The second axial magnetic bearing 9 and the first axial magnetic bearing 8 are spaced at an appropriate distance so that their respective magnetic circuits do not affect each other.

[0048] In the above embodiments, to ensure the safe operating range of the axial magnetic bearings and to maximize the utilization efficiency of the electromagnetic magnetomotive force of the first axial magnetic bearing 8 and the permanent magnet magnetomotive force of the second axial magnetic bearing 9, the length of the first air gap 803 is shorter than the length of the second air gap 903. The length of the first air gap 803 is 0.3mm to 0.6mm, and the length of the second air gap 903 is 0.6mm to 2.0mm. The gap length of the first air gap 803 is 0.3mm to 0.6mm to ensure the safe operating range of the first axial magnetic bearing 8 and to maximize the utilization efficiency of its electromagnetic magnetomotive force. The gap length of the second air gap 903 is 0.6mm to 2.0mm to ensure the safe operating range of the second axial magnetic bearing 9 and to maximize its electromagnetic magnetomotive force.

[0049] In some embodiments, the first axial magnetic bearing 8 may be disposed on the inner side, and the second axial magnetic bearing 9 may be disposed on the outer side.

[0050] Furthermore, a second radial bearing 11 is provided within the blind hole 1015. The lower part of the rotor main shaft 1021 passes through the inner hole of the second radial bearing 11. A safety gap of 3mm to 5mm is left between the lower end face of the rotor main shaft 1021 and the blind hole 1015. This gap can adapt to minor vibrations of the flywheel rotor 102 under external forces, preventing impact on the shaft end of the flywheel rotor 102. If the safety gap between the lower end face of the flywheel rotor 102 and the blind hole 1015 is too small (less than 3mm), minor vibrations of the flywheel rotor 102 may cause the shaft end of the flywheel rotor 102 to accidentally touch the bottom of the blind hole 1015, leading to instability of the entire flywheel rotor 102 and even damage to the entire flywheel energy storage device. If the safety gap between the lower end face of the flywheel rotor 102 and the blind hole 1015 is too large (greater than 5mm), the thickness of the base 1011 increases, resulting in an increase in the size and cost of the entire flywheel energy storage device.

[0051] In some embodiments, the second radial bearing 11 is an active control magnetic bearing. The outer circumferential surface of the second radial bearing 11 is interference-fitted with the inner circumferential surface of the blind hole 1015. A working air gap is provided between the inner circumferential surface of the second radial bearing 11 and the outer circumferential surface of the rotor main shaft 1021. In order to ensure that the magnetic bearing is not damaged during rotor landing and instability, a landing protection mechanical bearing of the flywheel rotor 102 is provided below the second radial bearing 11. The protection mechanical bearing is coaxially mounted with the second radial bearing 11. A protection gap is provided between its inner circumferential surface and the outer circumferential surface of the rotor main shaft 1021. The radial length of the protection gap is 1 / 3 to 1 / 5 of the radial length of the working air gap of the second radial bearing 11.

[0052] In some embodiments, the second radial bearing 11 is a mechanical bearing, and the outer circumferential surface of the second radial bearing 11 is in clearance fit with the inner circumferential surface of the blind hole 1015, and the inner circumferential surface of the second radial bearing 11 is in clearance fit with the outer circumferential surface of the rotor spindle 1021.

[0053] Furthermore, a first radial bearing 10 is provided in the lower part of the through hole 1014, and the upper part of the rotor main shaft 1021 passes through the inner hole of the first radial bearing 10.

[0054] In some embodiments, the first radial bearing 10 is an active control magnetic bearing. The outer circumferential surface of the first radial bearing 10 is interference-fitted with the inner circumferential surface of the through hole 1014. A working air gap is provided between the inner circumferential surface of the first radial bearing 10 and the outer circumferential surface of the rotor main shaft 1021. To ensure that the magnetic bearing is not damaged during rotor landing and instability, a landing protection mechanical bearing for the flywheel rotor 102 is provided on top of the first radial bearing 10. The protection mechanical bearing is coaxially mounted with the first radial bearing 10. A protective gap is provided between its inner circumferential surface and the outer circumferential surface of the rotor main shaft 1021. The radial length of the protective gap is 1 / 3 to 1 / 5 of the radial length of the working air gap of the first radial bearing 10.

[0055] In some embodiments, the first radial bearing 10 is a mechanical bearing, and the outer circumferential surface of the first radial bearing 10 is in clearance fit with the inner circumferential surface of the through hole 1014, and the inner circumferential surface of the first radial bearing 10 is in clearance fit with the outer circumferential surface of the rotor spindle 1021.

[0056] In some embodiments, the first radial bearing 10 and the second radial bearing 11 are both active control magnetic bearings. To ensure that the first radial bearing 10 and the second radial bearing 11 work synchronously, the working air gap of the first radial bearing 10 and the second radial bearing 11 is of the same length, and the protective gap of their protective mechanical bearing is also of the same length.

[0057] In this embodiment, the part of the rotor shaft 1021 extending from the flywheel body 1 is provided with a magnetic liquid rotary seal structure 6 for dynamically sealing with the rotor shaft 1021 to isolate the first chamber 4 from the second chamber 5.

[0058] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A split-type flywheel energy storage device, comprising a flywheel body (1), a motor assembly (2), and a mounting base (3). Its features are, The motor assembly (2) is detachably connected and fixed to the flywheel body (1) via the mounting base (3), and the combined structure of the motor assembly (2) and the mounting base (3) has a first chamber (4). The flywheel body (1) has a second chamber (5). The first chamber (4) and the second chamber (5) are isolated from each other. The motor shaft (201) of the motor assembly (2) extends toward the inner cavity of the mounting base (3), and the rotor main shaft (1021) of the flywheel body (1) extends out of the flywheel body (1) and toward the inner cavity of the mounting base (3). The motor shaft (201) and the rotor main shaft (1021) are connected by a heat-insulated detachable connection. The first chamber (4) is maintained in a low to medium vacuum environment that is conducive to the operation of the motor assembly (2), while the second chamber (5) is maintained in a high vacuum environment. The motor shaft (201) and the rotor main shaft (1021) are detachably connected by a heat-insulated coupling; or the motor shaft (201) and the rotor main shaft (1021) are coaxially arranged, and a heat insulation layer is provided between the motor shaft (201) and the rotor main shaft (1021) and a detachable fixed connector is used for connection; or the connecting end of the motor shaft (201) and / or the connecting end of the rotor main shaft (1021) has a heat-insulating coating, and the motor shaft (201) and the rotor main shaft (1021) are connected by a coupling; The flywheel body (1) includes a flywheel housing (101) and a flywheel rotor (102) disposed within the flywheel housing (101); at least two sets of axial magnetic bearings for active magnetic levitation control of the flywheel rotor (102) are provided between the flywheel housing (101) and the flywheel rotor (102), and the axial magnetic bearings are all located on the side of the flywheel rotor (102) opposite to the direction of gravity, and the two adjacent sets of axial magnetic bearings are arranged at intervals in the radial direction of the flywheel rotor (102); the axial magnetic bearings are a first axial magnetic bearing (8) and a second axial magnetic bearing (9) arranged adjacent to each other, the first axial magnetic bearing (8) is an electromagnetic attraction bearing, which supports the flywheel rotor (102) ... 2) 10% to 20% of the gravity, the second axial magnetic bearing (9) is a permanent magnet suction bearing, bearing 80% to 90% of the gravity of the flywheel rotor (102); under the controllable upward suction force of the first axial magnetic bearing (8) on the flywheel rotor (102), the upward suction force of the second axial magnetic bearing (9) on the flywheel rotor (102), and the gravity of the flywheel rotor (102), the axial active magnetic suspension control of the flywheel rotor (102) is realized, so that the flywheel rotor (102) can achieve axial active magnetic suspension stability by precise control of the small current of the electromagnetic suction bearing on the basis of static suspension force provided by the permanent magnet suction bearing, thereby greatly reducing the power consumption of suspension control.

2. The split-type flywheel energy storage device according to claim 1, characterized in that, The flywheel body (1), motor assembly (2) and mounting base (3) are manufactured separately and then assembled to form an overall device.

3. The split-type flywheel energy storage device according to claim 1, characterized in that, The mounting base (3) includes an upper boss (301), a lower boss (302), and a boss connecting part (303). Both the upper boss (301) and the lower boss (302) are circular rings of equal thickness, and the upper boss (301) and the lower boss (302) are arranged coaxially. The boss connecting part (303) connects the upper boss (301) and the lower boss (302) into a whole to enhance rigidity and ensure the coaxiality of the upper boss (301) and the lower boss (302).

4. The split-type flywheel energy storage device according to claim 3, characterized in that, The inner diameter of the lower boss (302) is larger than the inner diameter of the upper boss (301).

5. The split-type flywheel energy storage device according to claim 3, characterized in that, The upper boss (301), the lower boss (302), and the boss connecting part (303) are all integral plate structures. The upper boss (301) is sealed and fixedly connected to the motor assembly (2), and the lower boss (302) is sealed and fixedly connected to the flywheel body (1). The first chamber (4) is formed by the mounting base (3) and the motor assembly (2). The first chamber (4) is a sealed space so that the first chamber (4) can be maintained in a medium-low vacuum environment that is conducive to the operation of the motor assembly (2), thereby utilizing the motor rotor of the motor assembly (2) to drive airflow to effectively dissipate heat from the motor rotor and reduce the wind resistance loss of the motor rotor.

6. The split-type flywheel energy storage device according to claim 3, characterized in that, The boss connection part (303) adopts a hollow spoke structure so that the first chamber (4) can be connected to the atmosphere through the hollow gap, and then the motor rotor of the motor assembly (2) drives the air flow so that the first chamber (4) can fully exchange heat with the atmosphere to achieve heat dissipation.

7. The split-type flywheel energy storage device according to any one of claims 1 to 6, characterized in that, The flywheel rotor (102) includes a rotor main shaft (1021), a first rotor section (1022) arranged radially on the rotor main shaft (1021), and a second rotor section (1023) located on the outer periphery of the first rotor section (1022). The first rotor section (1022), the second rotor section (1023), and the rotor main shaft (1021) are manufactured separately and then assembled into a whole by temperature interference fit.

8. The split-type flywheel energy storage device according to any one of claims 1 to 6, characterized in that, The part of the flywheel body (1) where the rotor shaft (1021) extends out is provided with a magnetic fluid rotary seal structure (6) for dynamic sealing cooperation with the rotor shaft (1021) to isolate the first chamber (4) from the second chamber (5).

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