Flywheel energy storage system

Abstract

The invention discloses a flywheel energy storage system, which relates to the technical field of energy storage and comprises a shell, a flywheel, an electric power generation all-in-one machine and a cooling assembly, the interior of the shell is a vacuum closed cavity; a first rotating shaft and a second rotating shaft are coaxially arranged at the two ends of the flywheel respectively, the flywheel is installed in the shell through the first rotating shaft and the second rotating shaft, a first bearing assembly is coaxially arranged on the periphery of the first rotating shaft, and a second bearing assembly is coaxially arranged on the periphery of the second rotating shaft; the electric power generation all-in-one machine sleeves the periphery of the second rotating shaft and is used for converting electric energy and mechanical energy; the cooling assembly comprises a cooling pipe, the cooling pipe is inserted into a hollow cavity formed in the second rotating shaft, and a gap is reserved between the cooling pipe and the inner wall of the hollow cavity. Through the arrangement, the stability and the heat dissipation performance of the flywheel during rotation can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage, and particularly to a flywheel energy storage system. Background Art

[0002] Flywheel energy storage has long been applied to new energy vehicles. With the gradual development of renewable energy, the contradiction between power supply and demand imbalance has become increasingly obvious. Energy storage technology can provide strong support for aspects such as peak shaving of renewable energy power grids and improving power quality, improve the consumption level of renewable energy, promote the gradual transformation of traditional fossil energy to renewable energy, and realize new development in the energy industry.

[0003] Currently, common power energy storage technologies mainly include pumped-storage energy storage, compressed-air energy storage, flywheel energy storage, battery energy storage, supercapacitor energy storage, superconducting magnetic energy storage, etc. Flywheel energy storage has the advantages of high specific energy, high specific power, charge / discharge times independent of charge / discharge depth, high energy conversion efficiency, high reliability, easy maintenance, and environmental friendliness. These characteristics determine that flywheel energy storage is suitable for occasions that require short-term high-power electrical energy output and frequent charge / discharge, and has been applied in fields such as rail transit energy recovery, new energy grid-connected power generation, and uninterruptible power supplies.

[0004] However, the flywheel energy storage systems in the prior art have the following disadvantages: (1) The rotor is a fully hollow structure, and when bearing components with a large inertia such as flywheels, vibration, balance, and stability problems are likely to occur. (2) Regarding the structure of directly injecting cooling oil into the hollow cavity of the rotating shaft, at high speeds, the cooling oil will atomize and generate large mechanical losses, which will not only reduce the power of the flywheel system but also cause the thermal conductivity of the system to deteriorate, accelerating the aging and failure of the flywheel system.

[0005] Therefore, how to provide a flywheel energy storage system to at least partially solve the above drawbacks is a technical problem that those skilled in the art need to solve currently. Summary of the Invention

[0006] The object of the present invention is to provide a flywheel energy storage system that can improve the stability and heat dissipation performance during flywheel rotation.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A flywheel energy storage system, comprising:

[0009] A housing, the interior of which is a vacuum-sealed cavity;

[0010] A flywheel, with a first rotating shaft and a second rotating shaft coaxially arranged at both ends thereof. The flywheel is installed inside the housing through the first rotating shaft and the second rotating shaft. A first bearing assembly is coaxially arranged on the outer periphery of the first rotating shaft, and a second bearing assembly is coaxially arranged on the outer periphery of the second rotating shaft;

[0011] An integrated electric generator, sleeved around the outer periphery of the second rotating shaft, for the conversion between electric energy and mechanical energy;

[0012] A cooling assembly, including a cooling pipe, which is inserted into a hollow cavity provided inside the second rotating shaft, and there is a gap between the cooling pipe and the inner wall of the hollow cavity.

[0013] Preferably, the hollow cavity is of a columnar structure and is coaxially arranged with the second rotating shaft. The cooling pipe is fixedly connected to the end cover of the housing to prevent air from entering the vacuum cavity inside the housing.

[0014] Preferably, a number of annular fins are evenly arranged at intervals along the axial direction of the outer periphery of the cooling pipe, and there is a gap between the annular fins and the inner wall of the hollow cavity.

[0015] Preferably, a spiral fin in a spiral structure is arranged along the axial direction of the outer periphery of the cooling pipe, and there is a gap between the spiral fin and the inner wall of the hollow cavity.

[0016] Preferably, the cooling assembly further includes:

[0017] A cooling water tank, which contains cooling water inside;

[0018] A first water inlet pipe, one end of which extends into the cooling water tank and the other end is connected to a first water pump;

[0019] A water outlet pipe, one end of which is connected to the first water pump and the other end is internally communicated with the cooling water pipe;

[0020] A first water return pipe, one end of which is internally communicated with the cooling water pipe and the other end is communicated with the cooling water tank.

[0021] Preferably, the water outlet pipe extends to the top of the hollow cavity, and there is a gap between the end of the water outlet pipe and the top surface of the hollow cavity. A number of nozzles are arranged on the outer peripheral surface of the water outlet pipe located inside the cooling pipe.

[0022] Preferably, a first heat exchanger is arranged on the first water return pipe, and the first heat exchanger is used to reduce the temperature of the passing cooling water.

[0023] Preferably, water channels are arranged in the side wall of the housing located outside the second rotating shaft and are interconnected. The water channels are respectively communicated with the cooling water tank through a second water inlet pipe and a second water outlet pipe. The water channels, the second water inlet pipe, the second water outlet pipe and the cooling water tank form a closed loop. A second water pump is arranged on the second water inlet pipe and a second heat exchanger is arranged on the second water outlet pipe.

[0024] Preferably, the first bearing assembly includes an axial magnetic bearing sleeved on the outer periphery of the first rotating shaft, a first radial magnetic bearing, and a relief bearing. The axial magnetic bearing is used to limit the axial movement of the second rotating shaft, the first radial magnetic bearing is used to limit the radial swing of the second rotating shaft, and the relief bearing is used to cooperate with the axial magnetic bearing to bear the axial force of the flywheel.

[0025] Preferably, the second bearing assembly includes a second radial magnetic bearing and a protection bearing sleeved on the outer periphery of the second rotating shaft. The second radial magnetic bearing cooperates with the first radial magnetic bearing to support the flywheel, and the protection bearing is used to prevent the flywheel from moving downward.

[0026] Compared with the above background art, a flywheel energy storage system provided by the present invention includes: a housing, a flywheel, an integrated motor-generator, and a cooling assembly; the interior of the housing is a vacuum-sealed cavity; the two ends of the flywheel are coaxially provided with a first rotating shaft and a second rotating shaft respectively, and the flywheel is installed inside the housing through the first rotating shaft and the second rotating shaft. A first bearing assembly is coaxially arranged on the outer periphery of the first rotating shaft, and a second bearing assembly is coaxially arranged on the outer periphery of the second rotating shaft; the integrated motor-generator is sleeved on the outer periphery of the second rotating shaft and is used for the conversion of electrical energy and mechanical energy; the cooling assembly includes a cooling pipe, and the cooling pipe is inserted into a hollow cavity arranged inside the second rotating shaft and there is a gap between the cooling pipe and the inner wall of the hollow cavity.

[0027] In this embodiment, the housing extends vertically, and the flywheel is vertically installed inside the housing, wherein the flywheel is supported by the first rotating shaft and the second rotating shaft coaxially arranged at its upper and lower ends, and the first bearing assembly and the second bearing assembly sleeved on the outer peripheries of the first rotating shaft and the second rotating shaft respectively; it should be noted that the second rotating shaft in this embodiment, that is, the rotating shaft below the flywheel, is provided with a hollow cavity inside, and a cooling pipe is inserted into the hollow cavity; in this way, since the integrated motor-generator generates the most heat during operation, therefore, arranging the cooling pipe for cooling inside the second rotating shaft can avoid setting the entire flywheel and the first rotating shaft as hollow structures, which can improve the stability of the flywheel during rotation; moreover, the cooling pipe installed inside the second rotating shaft in this embodiment does not contact the second rotating shaft, and transfers heat through the way of thermal radiation, which can maintain a high thermal conductivity for a long time, thereby improving the cooling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0029] Figure 1 Schematic structural diagram of the flywheel energy storage system provided by the embodiment of the present invention;

[0030] Figure 2 is an embodiment of a cooling pipe;

[0031] Figure 3 is another embodiment of a cooling pipe.

[0032] Wherein:

[0033] 100 - housing, 110 - vacuum pump, 120 - water channel, 130 - end cover;

[0034] 200 - flywheel;

[0035] 300 - first rotating shaft;

[0036] 400 - second rotating shaft, 410 - hollow cavity;

[0037] 500 - integrated motor - generator;

[0038] 610 - cooling pipe, 611 - annular fin, 612 - spiral fin, 620 - cooling water tank, 630 - first water inlet pipe, 640 - first water pump, 650 - water outlet pipe, 660 - first return water pipe, 661 - first heat exchanger;

[0039] 710 - axial magnetic bearing, 720 - first radial magnetic bearing, 730 - unloading bearing;

[0040] 810 - second radial magnetic bearing, 820 - protection bearing. Detailed implementation manners

[0041] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0042] In order to enable those skilled in the art in the technical field to better understand the solution of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0043] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left" and "right" and the like is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the indicated position or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0044] The object of the present invention is to provide a flywheel energy storage system, which can improve the stability and heat dissipation performance during the rotation of the flywheel.

[0045] To achieve the above object, the present invention provides the following technical solutions:

[0046] Please refer to Figures 1 to 3 , a flywheel energy storage system provided in this embodiment includes: a housing 100, a flywheel 200, an integrated motor - generator 500, and a cooling assembly; the interior of the housing 100 is a vacuum - sealed cavity; both ends of the flywheel 200 are coaxially provided with a first rotating shaft 300 and a second rotating shaft 400 respectively, the flywheel 200 is installed inside the housing 100 through the first rotating shaft 300 and the second rotating shaft 400, a first bearing assembly is coaxially provided on the outer periphery of the first rotating shaft 300, and a second bearing assembly is coaxially provided on the outer periphery of the second rotating shaft 400; the integrated motor - generator 500 is sleeved on the outer periphery of the second rotating shaft 400 and is used for the conversion between electrical energy and mechanical energy; the cooling assembly includes a cooling pipe 610, the cooling pipe 610 is inserted into a hollow cavity 410 provided inside the second rotating shaft 400, and there is a gap between the cooling pipe 610 and the inner wall of the hollow cavity 410.

[0047] The hollow cavity 410 can be regarded as an open cavity. The hollow cavity 410 is opened from the bottom - side end of the second rotating shaft 400 and extends along the axial direction of the second rotating shaft 400, and at least extends to the axial position of the integrated motor - generator 500, but should not reach the position of the flywheel 200. That is to say, the hollow cavity 410 should not be a through - hole, but a counterbore or a blind hole. Taking the orientation shown in the appendix Figure 1 as an example, the bottom of the hollow cavity 410 is located at the bottom - side end of the second rotating shaft 400, and the top of the hollow cavity 410 is at least flush with the top of the integrated motor - generator 500, and can even be higher than the top of the integrated motor - generator 500. Such a setting can maximize the length of the cooling pipe 610, that is, increase the cooling effect, and at the same time help to reduce the weight of the second rotating shaft 400.

[0048] In this embodiment, the housing 100 extends vertically, and its lowermost part is an end - cover. When it is necessary to install other components inside the housing 100, the end - cover at the bottom of the housing 100 can be taken out first, and after the installation of other components is completed, the end - cover is fixedly installed at the bottom of the housing 100, so as to form a sealed environment inside the housing 100; and in order to reduce the energy loss caused by air friction during the rotation of the flywheel 200, the inside of the housing 100 is also pumped to a vacuum environment. Specifically, in this embodiment, the air inside the housing 100 is pumped out by a vacuum pump 110 communicated with the inside of the housing 100.

[0049] In this embodiment, the flywheel energy storage system is vertically arranged, and the housing 100 also extends vertically. The flywheel 200 is also vertically installed inside the housing 100. The flywheel 200 is supported by the first rotating shaft 300 and the second rotating shaft 400 coaxially arranged at its upper and lower ends, and the first bearing assembly and the second bearing assembly sleeved on the outer peripheries of the first rotating shaft 300 and the second rotating shaft 400 respectively; that is to say, the first bearing assembly supports the first rotating shaft 300, the second bearing assembly supports the second rotating shaft 400, and the first rotating shaft 300 and the second rotating shaft 400 jointly support the flywheel 200.

[0050] It can be understood that the integrated motor-generator 500 in the flywheel energy storage system is a core component. It can drive the flywheel 200 to rotate at a high speed in the charging state (electrical energy is converted into kinetic energy), and can also be dragged by the flywheel 200 to rotate in the discharging state (kinetic energy is converted into electrical energy). However, no matter what working state it is in, a large amount of heat will be generated. And in this embodiment, it is installed on the outer periphery of the second rotating shaft 400.

[0051] Therefore, the second rotating shaft 400 in this embodiment, that is, the rotating shaft below the flywheel 200, is not a solid structure like the rotating shafts in the prior art. A hollow cavity 410 is arranged inside it, and a cooling pipe 610 is inserted inside the hollow cavity 410; in this way, since the integrated motor-generator 500 generates the most heat during operation, the cooling pipe 610 can absorb the heat generated by the integrated motor-generator 500 to the greatest extent in the hollow cavity 410, thereby avoiding the influence of high temperature on the integrated motor-generator 500; in addition, only setting the second rotating shaft 400 where the integrated motor-generator 500 is installed as the hollow cavity 410 can not only dissipate heat from the flywheel energy storage system to the greatest extent, but also avoid setting the entire flywheel 200 and the first rotating shaft 300 as hollow structures, which can improve the stability of the flywheel 200 during rotation; moreover, the cooling pipe 610 installed in the second rotating shaft 400 in this embodiment does not contact the second rotating shaft 400 and transfers heat by means of thermal radiation, and can maintain a high thermal conductivity for a long time, thereby improving the cooling efficiency.

[0052] With such a setting, the cooling structure is simple, the cost is low, and it is easy to implement. Moreover, the cooling pipe 610 is installed in the hollow cavity 410 of the second rotating shaft 400, which can not only cool the rotor well, but also does not increase the mechanical loss of the system. And the hollow cavity 410 structure is better for the vibration, balance and stability of the entire flywheel 200 system.

[0053] In addition, in this embodiment, the heat pipe can replace the cooling pipe 610, provided that the airtightness of the system is satisfied, and the lower end of the heat pipe must be cooled to achieve heat transfer. Moreover, in this embodiment, in order to improve the heat conduction efficiency, the inner wall of the hollow cavity 410 is subjected to surface heat treatment to increase the emissivity and enhance the outward radiation ability. At the same time, the outer wall of the cooling pipe 610 is also correspondingly subjected to surface treatment to enhance the absorption of radiant heat, improve the absorptivity, and enhance the heat absorption ability. The material of the cooling pipe 610 in this embodiment is preferably a metal or alloy with strong thermal conductivity such as copper or aluminum.

[0054] Preferably, the hollow cavity 410 is a columnar structure and is coaxially arranged with the second rotating shaft 400. The cooling pipe 610 is fixedly connected to the end cover of the housing 100 to prevent air from entering the vacuum chamber inside the housing 100.

[0055] In this embodiment, the hollow cavity 410 is a cylindrical cavity structure arranged at the axis of the second rotating shaft 400. At the same time, the cooling pipe 610 in this embodiment extends into the hollow cavity 410. To ensure the airtight environment inside the housing 100, the cooling pipe 610 is integrally rigidly connected to the position of the end cover of the housing 100 corresponding to the hollow cavity 410, and it is ensured that there is no contact between the cooling pipe 610 and the inner wall of the hollow cavity 410 after it extends into the hollow cavity 410. The connection method can be welding, threaded connection, or flange connection, etc. Specifically, as Figure 1 shown, the top of the cooling pipe 610 is closed, while the bottom of the cooling pipe 610 is open and is rigidly connected to the upper side of the end cover. The cooling effect can be achieved by setting heat-absorbing devices or components inside the cooling pipe 610. In this way, the airtightness of the system can be well ensured.

[0056] Preferably, a plurality of annular fins 611 are arranged at intervals along the axial direction on the outer circumference of the cooling pipe 610, and there is a gap between the annular fins 611 and the inner wall of the hollow cavity 410.

[0057] In this embodiment, the cooling pipe 610 can be a smooth pipe, or fins can be provided on its outer circumference to increase the heat transfer efficiency.

[0058] As an option, a plurality of annular fins 611 can be provided on the outer circumference of the cooling pipe 610. Specifically, as Figure 2 shown, these annular fins 611 are all perpendicular to the axis of the cooling pipe 610 and are evenly distributed at intervals along the axial direction.

[0059] Preferably, a spiral fin 612 in a spiral structure is arranged along the axial direction on the outer circumference of the cooling pipe 610, and there is a gap between the spiral fin 612 and the inner wall of the hollow cavity 410.

[0060] As an alternative, the fins provided on the outer periphery of the cooling pipe 610 are spiral fins 612, and the axis of the spiral fins 612 coincides with the axis of the cooling pipe 610, specifically as shown in Figure 3 shown.

[0061] It should be noted that whether it is the annular fins 611 or the spiral fins 612, neither of them is in contact with the inner wall of the hollow cavity 410, and there is a certain gap between them and the inner wall; at the same time, the surfaces of the annular fins 611 and the spiral fins 612 are also surface-treated to improve the heat absorption rate; in this way, both the annular fins 611 or the spiral fins 612 provided on the outer periphery of the cooling pipe 610 can increase the surface area, thereby improving the heat transfer efficiency of the cooling pipe 610.

[0062] Preferably, the cooling assembly further includes: a cooling water tank 620, a first water inlet pipe 630, a water outlet pipe 650, and a first water return pipe 660; the cooling water tank 620 contains cooling water inside; one end of the first water inlet pipe 630 extends into the cooling water tank 620, and the other end is connected to the first water pump 640; one end of the water outlet pipe 650 is connected to the first water pump 640, and the other end is in internal communication with the cooling pipe; one end of the first water return pipe 660 is in internal communication with the cooling pipe, and the other end is connected to the cooling water tank 620.

[0063] Specifically as shown in Figure 1 shown, the cooling assembly further includes a cooling water tank 620. Cooling water can be stored in the cooling water tank 620. A first water inlet pipe 630 extends from the cooling water tank 620. The first water inlet pipe 630 is connected to the water inlet of the water pump. The water outlet of the first water pump 640 is connected to a water outlet pipe 650, and the water outlet pipe 650 is inserted into the cooling pipe 610. In this way, the first water pump 640 can pump the cooling water into the cooling pipe 610 to cool it; at the same time, the lower part of the cooling pipe 610 is connected to the water outlet pipe 650, that is, the cooled cooling water will flow back into the cooling water tank 620 through the first water return pipe 660 again.

[0064] It should be noted that the liquid in the cooling water tank 620 can be water, or other green pollution-free and non-corrosive liquids, such as gearbox oil, a mixture of water and ethylene glycol, etc., or a Freon gas that easily undergoes a phase change when heated.

[0065] To improve the cooling effect, a temperature sensor can also be provided in the first return water pipe 660. The temperature sensor is used to detect the liquid temperature in the first return water pipe 660. The temperature sensor is connected to a controller. The controller is used to obtain the liquid temperature in the first return water pipe 660 collected by the temperature sensor. The controller is also connected to the first water pump 640. The controller is used to control the running speed of the first water pump 640. When the controller determines that the liquid temperature in the first return water pipe 660 collected by the temperature sensor is greater than the preset temperature, the controller controls the running speed of the first water pump 640 to increase, so as to quickly achieve heat dissipation and ensure reliable operation.

[0066] Further, the controller can also be configured to not judge in real time whether the liquid temperature in the first return water pipe 660 collected by the temperature sensor is greater than the preset temperature, but add a limiting condition. When the controller obtains that the rotation of the flywheel 200 exceeds the preset speed, it starts to judge whether the liquid temperature in the first return water pipe 660 collected by the temperature sensor is greater than the preset temperature. When within a preset time period, the current speed of the flywheel 200 always exceeds the preset speed, and within the preset time period, whether the liquid temperature in the first return water pipe 660 is always greater than the preset temperature, then control the running speed of the first water pump 640 to increase. The preset time period can be determined according to the current speed of the flywheel 200. Generally, the lower the current speed of the flywheel 200, the longer the preset time period, and the higher the current speed of the flywheel 200, the shorter the preset time period. The preset speed can be set to different speed values according to actual needs or experience. The preset temperature can be determined according to 20%-80% of the temperature when operation failure occurs due to poor heat dissipation.

[0067] Preferably, the water outlet pipe 650 extends into the top of the hollow cavity 410, and there is a gap between the end of the water outlet pipe 650 and the top surface of the hollow cavity 410. A plurality of nozzles are provided on the outer peripheral surface of the water outlet pipe 650 located in the cooling pipe 610.

[0068] Furthermore, in order to be able to absorb heat and cool down the cooling pipe 610, the water outlet pipe 650 in this embodiment extends to the topmost part of the hollow cavity 410 but does not contact its top. At the same time, multiple nozzles can be provided on the part of the water outlet pipe 650 located in the cooling pipe 610. These nozzles are evenly distributed on the pipe body of the water outlet pipe 650, and the spraying range of the nozzles is circular. In this way, the cooling efficiency of the cooling pipe 610 can be maximally improved, and the heat absorption of the cooling pipe 610 can be ensured to be uniform.

[0069] Preferably, a first heat exchanger 661 is provided on the first return water pipe 661. The first heat exchanger 661 is used to reduce the temperature of the passing cooling water.

[0070] Further, in order to ensure that the coolant in the cooling water tank 620 always remains at a low temperature to cool the second rotating shaft 400, a first heat exchanger 661 is also provided on the first return water pipe 660 in this embodiment. The first heat exchanger 661 can cool the cooling water and then discharge the cooled cooling water back into the cooling water tank 620.

[0071] Preferably, a water channel 120 that communicates with each other is provided in the side wall of the housing 100 outside the second rotating shaft 400. The water channel 120 is respectively connected to the cooling water tank 620 through a second water inlet pipe and a second water outlet pipe 650. The water channel 120, the second water inlet pipe, and the second water outlet pipe 650 form a closed loop with the cooling water tank 620. A second water pump is provided on the second water inlet pipe, and a second heat exchanger is provided on the second water outlet pipe 650.

[0072] Furthermore, in order to ensure that the motor-generator unit 500 in the flywheel energy storage system is not affected by high temperature during operation, several loops of water channels 120 are provided at the position of the housing 100 corresponding to the motor-generator unit 500. These water channels 120 are arranged on the inner wall of the housing 100 and can absorb the heat generated by the motor-generator unit 500 when cooling water passes through. Specifically, in this embodiment, the cooling water circulation process in the water channel 120 is similar to that in the cooling pipe 610. The cooling water tank 620 is connected to the water inlet of the water channel 120 through the second water inlet pipe, and the water outlet of the water channel 120 is connected to the cooling water tank 620 through the second water outlet pipe 650. A power source, a second water pump, is provided on the second water inlet pipe, and a second heat exchanger is provided on the second water outlet pipe 650. The second water pump can pump the cooling water in the cooling water tank 620 into the water channel 120. After absorbing heat in the water channel 120, the cooling water will enter the second heat exchanger from the drain port and be discharged back into the cooling water tank 620 after being cooled by the second heat exchanger.

[0073] Preferably, the first bearing assembly includes an axial magnetic bearing 710 sleeved on the outer periphery of the first rotating shaft 300, a first radial magnetic bearing 720, and a thrust bearing 730. The axial magnetic bearing 710 is used to limit the axial movement of the second rotating shaft 400, the first radial magnetic bearing 720 is used to limit the radial swing of the second rotating shaft 400, and the thrust bearing 730 is used to cooperate with the axial magnetic bearing 710 to bear the axial force of the flywheel 200.

[0074] Further, the second bearing assembly includes a second radial magnetic bearing 810 and a protection bearing 820 sleeved on the outer periphery of the second rotating shaft 400. The second radial magnetic bearing 810 cooperates with the first radial magnetic bearing 720 to support the flywheel 200, and the protection bearing 820 is used to prevent the flywheel 200 from moving downward.

[0075] In this embodiment, an axial magnetic bearing 710 and a first radial magnetic bearing 720 are sleeved on the first rotating shaft 300, and a second radial magnetic bearing 810 and a protective bearing 820 are sleeved on the second rotating shaft 400. While ensuring the smooth rotation of the first rotating shaft 300 and the second rotating shaft 400, the axial magnetic bearing 710, the first radial magnetic bearing 720, and the second radial magnetic bearing 810 respectively act on them with forces in different directions. Among them, the axial magnetic bearing 710 can apply an axial force to the first rotating shaft 300 to ensure that the flywheel 200 does not axially move. The first radial magnetic bearing 720 and the second radial magnetic bearing 810 respectively apply radial forces to the first rotating shaft 300 and the second rotating shaft 400 to prevent them from swaying left and right. The unloading bearing 730 is installed at a position close to the upper end face of the flywheel 200. It can be a permanent magnet, which applies an axial force to the flywheel 200, so that it can share the force borne by the axial magnetic bearing, thereby further increasing the stability of the flywheel energy storage system. The protective bearing 820 is a common bearing, which is installed at the lower end of the second rotating shaft 400, and it can prevent the flywheel 200 from moving downward due to an accident.

[0076] It should be noted that in this specification, relational terms such as first and second are only used to distinguish one entity from several other entities, and do not necessarily require or imply any actual relationship or order between these entities.

[0077] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the various embodiments can be referred to each other.

[0078] The above has introduced the embodiments provided by the present invention in detail. Specific examples are used in this article to elaborate on the principles and implementation manners of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the present invention.

Claims

1. A flywheel energy storage system, characterized in that, Comprising: A housing (100) with a vacuum-sealed cavity inside; A flywheel (200) having a first rotating shaft (300) and a second rotating shaft (400) coaxially arranged at both ends thereof. The flywheel (200) is installed inside the housing (100) through the first rotating shaft (300) and the second rotating shaft (400). A first bearing assembly is coaxially arranged on the outer periphery of the first rotating shaft (300), and a second bearing assembly is coaxially arranged on the outer periphery of the second rotating shaft (400); An integrated motor-generator (500) sleeved on the outer periphery of the second rotating shaft (400) for converting electrical energy and mechanical energy; A cooling assembly including a cooling pipe (610). The cooling pipe (610) is inserted into a hollow cavity (410) provided inside the second rotating shaft (400), and there is a gap between the cooling pipe (610) and the inner wall of the hollow cavity (410).

2. The flywheel energy storage system according to claim 1, wherein The hollow cavity (410) is a columnar structure and is coaxially arranged with the second rotating shaft (400). The cooling pipe (610) is fixedly connected to the end cover (130) of the housing (100) to prevent air from entering the vacuum chamber inside the housing (100).

3. The flywheel energy storage system according to claim 2, wherein A plurality of annular fins (611) are arranged at intervals and evenly along the axial direction of the outer periphery of the cooling pipe (610), and there is a gap between the annular fins (611) and the inner wall of the hollow cavity (410).

4. The flywheel energy storage system according to claim 2, wherein A spiral fin (612) in a spiral structure is arranged along the axial direction of the outer periphery of the cooling pipe (610), and there is a gap between the spiral fin (612) and the inner wall of the hollow cavity (410).

5. The flywheel energy storage system according to claim 3 or 4, characterized in that, The cooling assembly further includes: A cooling water tank (620) filled with cooling water inside; A first water inlet pipe (630) with one end extending into the cooling water tank (620) and the other end connected to a first water pump (640); A water outlet pipe (650) with one end connected to the first water pump (640) and the other end internally communicating with the cooling water pipe; A first water return pipe (660) with one end internally communicating with the cooling water pipe and the other end communicating with the cooling water tank (620).

6. The flywheel energy storage system according to claim 5, wherein The water outlet pipe (650) extends to the top of the hollow cavity (410), and there is a gap between the end of the water outlet pipe (650) and the top surface of the hollow cavity (410). A plurality of nozzles are arranged on the outer peripheral surface of the water outlet pipe (650) located inside the cooling pipe (610).

7. The flywheel energy storage system according to claim 5, wherein, A first heat exchanger (661) is arranged on the first water return pipe (660), and the first heat exchanger (661) is used to reduce the temperature of the passing cooling water.

8. The flywheel energy storage system according to claim 5, wherein, A water channel (120) is arranged inside the side wall of the housing (100) outside the second rotating shaft (400) and is interconnected. The water channel (120) is respectively communicated with the cooling water tank (620) through a second water inlet pipe and a second water outlet pipe (650). The water channel (120), the second water inlet pipe, and the second water outlet pipe (650) form a closed loop with the cooling water tank (620). A second water pump is arranged on the second water inlet pipe, and a second heat exchanger is arranged on the second water outlet pipe (650).

9. The flywheel energy storage system according to claim 1, wherein The first bearing assembly includes an axial magnetic bearing (710), a first radial magnetic bearing (720), and a relief bearing (730) sleeved on the outer periphery of the first rotating shaft (300). The axial magnetic bearing (710) is used to limit the axial movement of the second rotating shaft (400), the first radial magnetic bearing (720) is used to limit the radial swing of the second rotating shaft (400), and the relief bearing (730) is used to cooperate with the axial magnetic bearing (710) to bear the axial force of the flywheel (200).

10. The flywheel energy storage system according to claim 9, characterized in that, The second bearing assembly includes a second radial magnetic bearing (810) and a protection bearing (820) sleeved on the outer periphery of the second rotating shaft (400). The second radial magnetic bearing (810) cooperates with the first radial magnetic bearing (720) to support the flywheel (200), and the protection bearing (820) is used to prevent the flywheel (200) from moving downward.

Images