Flywheel energy storage device for rotor liquid gas cooling

Abstract

The invention discloses a flywheel energy storage device for rotor liquid gas cooling. The flywheel energy storage device comprises a shell, and a motor and a flywheel body connected with the motor are arranged in the shell; the motor comprises a rotor and a stator, a rotor hollow shaft penetrates through the central axis of the rotor, a deep pipe is arranged on the inner wall of the rotor hollow shaft, the end part of the deep pipe is connected with an air inlet pipe, and an air outlet hole is formed in the end part of the rotor hollow shaft; when the liquid gas medium flows into the deep pipe through the gas inlet pipe and flows out of the gas outlet through the rotor hollow shaft, heat accumulated in the operation process of the flywheel rotor can be guided out, a large amount of heat can be absorbed through gas-liquid phase change of liquefied gas, the rotor heat is transmitted out, a motor is cooled, the heat exchange efficiency is high, and the service life of the motor is prolonged. The flywheel energy storage system is simple in structure, environment-friendly and pollution-free, the effect of long-time stable operation of the flywheel energy storage system can be achieved, the fin rings are arranged in the hollow shaft of the rotor, liquid gas can be prevented from flying out in the rotating process of the rotor, and the heat exchange effect is improved.

Description

Technical Field

[0001] This invention relates to the field of flywheel energy storage, and in particular to a flywheel energy storage device with rotor liquid gas cooling. Background Technology

[0002] As a type of physical energy storage, flywheel energy storage boasts advantages such as high specific energy, high specific power, decoupling of charge / discharge cycles and depth of charge / discharge, high efficiency, and environmental friendliness, making it suitable for applications in transportation, grid regulation, new energy power generation regulation, and uninterruptible power supplies. A flywheel energy storage system mainly comprises the flywheel body, motor, bearings, protective housing, and converter. The motor is a key component of the flywheel energy storage system, achieving the mutual conversion of electrical energy and mechanical energy through an integrated motor / generator. During operation, the motor inevitably generates losses, which are ultimately converted into heat, causing the motor temperature to rise. With the increasing speed and power of flywheel energy storage systems, to reduce wind losses in the flywheel body, the flywheel body and motor are placed in a vacuum environment. This results in a lack of heat dissipation paths for the heat generated on the flywheel rotor, potentially leading to thermal safety issues such as rotor temperature runaway, magnet demagnetization, reduced efficiency, and even flywheel motor damage.

[0003] Existing flywheel rotor cooling methods mostly employ techniques such as increasing radiative coatings and radiative heat transfer area, or in-shaft oil cooling. However, the heat transfer capacity of these methods, while enhancing radiative heat transfer, is limited and cannot fully meet the rotor's heat dissipation requirements. In-shaft oil cooling solutions involve complex system design, demand high standards for the heat transfer fluid (heat transfer oil) and pumps, are costly, and their effectiveness requires further experimental verification. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is that the existing cooling methods for flywheel rotors mostly adopt the methods of increasing the radiation coating and radiation heat exchange area, and internal shaft oil cooling, etc. The heat exchange capacity of the enhanced radiation heat exchange method is limited and cannot fully meet the heat dissipation requirements of the rotor.

[0005] The above-mentioned technical problems are solved by the following technical solution: This invention proposes a flywheel energy storage device with rotor liquid gas cooling, which includes a housing, a motor and a flywheel body connected to the motor are arranged inside the housing; the motor includes a rotor and a stator, a hollow rotor shaft is passed through the central shaft of the rotor, a deep tube is arranged on the inner wall of the hollow rotor shaft, the end of the deep tube is connected to an air inlet pipe, and an air outlet is arranged at the end of the hollow rotor shaft; the liquid gas medium can dissipate the heat accumulated during the operation of the flywheel rotor by flowing into the deep tube through the air inlet pipe and flowing out through the air outlet of the hollow rotor shaft.

[0006] In a preferred embodiment of the rotor-cooled flywheel energy storage device of the present invention: a finned ring is provided on the inner wall of the rotor hollow shaft, and the end of the inlet tube away from the outlet hole extends into the bottom of the rotor hollow shaft, so that the liquid gas medium enters the bottom of the rotor hollow shaft along the inlet tube, and moves upward from the bottom of the rotor hollow shaft through the finned ring to the outlet hole for discharge; the finned ring is used to prevent the liquid from flowing outward under the action of centrifugal force, and the heat exchange area between the liquefied gas and the vaporized gas can be increased through the finned ring.

[0007] In a preferred embodiment of the rotor-cooled flywheel energy storage device of the present invention: a top cover is provided through the end of the rotor hollow shaft, and the top cover is movably connected to the housing; the top cover is used to keep the position of the air inlet pipe inside the rotor hollow shaft fixed.

[0008] In a preferred embodiment of the rotor liquid gas cooled flywheel energy storage device of the present invention: the fin ring and the rotor hollow shaft are interference fit, and the top of the rotor hollow shaft is provided with a pressure ring to prevent the fin ring from moving.

[0009] In a preferred embodiment of the rotor liquid gas cooled flywheel energy storage device of the present invention: the top cover, the in-feed tube, the pressure ring and the fin ring together form the internal flow channel of the rotor shaft.

[0010] In a preferred embodiment of the rotor-cooled flywheel energy storage device of the present invention: the top cover and the hollow shaft of the rotor are sealed by a sealing ring, which is used to maintain a negative pressure environment inside the housing.

[0011] In a preferred embodiment of the rotor-cooled flywheel energy storage device of the present invention: the end of the air inlet pipe away from the inlet pipe is connected to a liquefied gas tank, and the outer wall of the liquefied gas tank is provided with a heat insulation component.

[0012] In a preferred embodiment of the rotor liquid gas cooled flywheel energy storage device of the present invention: an electromagnetic valve is provided on the air inlet pipe, and the opening and closing state of the electromagnetic valve is controlled by a control program.

[0013] In a preferred embodiment of the rotor liquid gas cooled flywheel energy storage device of the present invention: a stator water jacket is provided on the outer wall of the motor stator, and the stator water jacket is used to cool the stator.

[0014] In a preferred embodiment of the rotor liquid gas cooled flywheel energy storage device of the present invention: the housing is connected to a vacuum pump through a pipeline, and the vacuum pump is used to maintain the vacuum state of the inner wall of the housing.

[0015] The beneficial effects of this invention are as follows: by utilizing the gas-liquid phase change of liquefied gas, a large amount of heat can be absorbed and the rotor heat can be transferred out to cool the motor. It has high heat exchange efficiency, is environmentally friendly and pollution-free, and can achieve the effect of long-term stable operation of the flywheel energy storage system.

[0016] By incorporating finned rings within the hollow shaft of the rotor, liquid gas can be prevented from escaping during rotor rotation, while also increasing the heat exchange area and improving heat exchange efficiency.

[0017] Furthermore, the cooling system of the present invention has a simple structure and is easy to assemble. It can control the opening of the solenoid valve to inject liquid gas into the hollow shaft in real time according to the rotor temperature, which is flexible and convenient. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention. Wherein:

[0019] Figure 1 A schematic diagram of the overall structure of a flywheel energy storage device with rotor liquid gas cooling is shown.

[0020] Figure 2 An enlarged view of part of the structure of a flywheel energy storage device with rotor liquid gas cooling is shown;

[0021] Figure 3 A top view of the fin ring of a flywheel energy storage device with rotor liquid gas cooling is shown.

[0022] In the diagram: 1. Liquefied gas tank; 2. Solenoid valve; 3. Top cover; 4. Gas outlet; 5. Pressure ring; 6. Sealing ring; 7. Upper protective bearing; 8. Deep tube; 9. Upper radial bearing; 10. Finned ring; 11. Motor rotor; 12. Motor stator; 13. Hollow rotor shaft; 14. Rotor shaft internal flow channel; 15. Stator water jacket; 16. Flywheel body; 17. Lower radial bearing; 18. Thrust bearing; 19. Lower protective bearing; 20. Sealing housing; 21. Vacuum pump. Detailed Implementation

[0023] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0024] The terminology used in this invention is that which is currently widely used in the art in consideration of the function of the invention; however, these terms may vary according to the intent of those skilled in the art, precedent, or new technology in the art. Furthermore, specific terms may be chosen by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the invention. Therefore, the terms used in this specification should not be construed as simple names, but rather based on their meanings and the overall description of the invention.

[0025] Reference Figures 1-2 This embodiment provides a rotor-cooled flywheel energy storage device, including a housing, a motor and a flywheel body 16 connected to the motor are disposed inside the housing; the motor includes a rotor and a stator, a rotor hollow shaft 13 is passed through the central shaft of the rotor, a penetration tube 8 is provided on the inner wall of the rotor hollow shaft 13, the end of the penetration tube 8 is connected to the air inlet pipe, and an air outlet is provided at the end of the rotor hollow shaft 13.

[0026] The liquid gas medium flows into the inlet pipe through the inlet pipe 8 and flows out through the outlet hole through the hollow shaft 13 of the rotor, which can dissipate the heat accumulated during the operation of the flywheel rotor.

[0027] In the existing technical field, common methods for effectively cooling flywheel rotors include adding radiative coatings, increasing the radiative heat transfer area, and implementing oil cooling inside the shaft. However, these cooling methods, which enhance radiative heat transfer, have certain limitations in their heat transfer capacity and often fail to achieve the expected heat dissipation effect, thus failing to fully meet the enormous heat dissipation requirements generated by the flywheel rotor during high-speed operation.

[0028] Our invention, by designing the central shaft of the motor as a hollow structure, allows the liquid gas medium to flow smoothly into the inlet pipe 8 through the inlet pipe, and further through the hollow shaft portion of the rotor, finally exiting from the outlet. During this flow process, the liquid gas medium undergoes a phase change, effectively absorbing the heat generated by the motor during operation. This cooling method not only fully utilizes the heat absorption characteristics of the liquid gas medium's phase change, but also features a simple and clear overall structural design, extremely convenient and efficient operation, and significantly improves the heat dissipation effect of the flywheel rotor.

[0029] In some implementations, refer to Figures 1-3 The inner wall of the hollow rotor shaft 13 is provided with a finned ring 10. The end of the inlet tube 8 away from the outlet extends into the bottom of the hollow rotor shaft 13, so that the liquid gas medium enters the bottom of the hollow rotor shaft 13 along the inlet tube 8, and moves upward from the bottom of the hollow rotor shaft 13 through the finned ring 10 to the outlet for discharge. The finned ring 10 is used to prevent the liquid from flowing out under the action of centrifugal force. The finned ring 10 can increase the heat exchange area between the liquefied gas and the vaporized gas.

[0030] It should be noted that the liquid gas medium (such as liquid nitrogen or liquefied carbon dioxide) flows into the inlet pipe 8 through the inlet pipe and enters the bottom of the rotor hollow shaft 13 along the inlet pipe 8. Under the action of the fin ring 10 set on the inner wall of the rotor hollow shaft 13, the liquid gas is prevented from flowing out under the action of centrifugal force. At the same time, the fin ring 10 promotes the vaporization of the liquid gas by increasing the heat exchange area. The vaporized gas is discharged from the outlet hole, thereby efficiently removing the heat accumulated during the operation of the flywheel rotor and realizing phase change cooling.

[0031] Specifically, a top cover 3 is inserted through the end of the hollow rotor shaft 13, and the top cover 3 is movably connected to the housing; the top cover 3 is used to keep the position of the air intake pipe inside the hollow rotor shaft 13 fixed.

[0032] It should be noted that the top cover 3 not only covers the end of the hollow rotor shaft 13, but is also tightly connected to it. The top cover 3 is bolted to the housing to facilitate adjustment or disassembly as needed. In addition, the main function of the top cover 3 is to ensure that the air intake pipe inside the hollow rotor shaft 13 can be kept in a fixed position, preventing it from shifting or loosening during operation, thereby ensuring the normal operation and stability of the entire device.

[0033] Furthermore, the finned ring 10 and the hollow rotor shaft 13 are interference fit, and the top of the hollow rotor shaft 13 is provided with a pressure ring 5 to prevent the finned ring 10 from moving.

[0034] It should be noted that the finned ring 10 and the hollow rotor shaft 13 are fitted with an interference fit to ensure a tight connection and prevent relative displacement. Furthermore, to further stabilize the position of the finned ring 10, a pressure ring 5 is specially designed and installed on the top of the hollow rotor shaft 13. This pressure ring 5 effectively prevents any movement of the finned ring 10 during operation, thereby ensuring the stability and reliability of the entire device.

[0035] Furthermore, the top cover 3, the inlet tube 8, the pressure ring 5, and the finned ring 10 together form the internal flow channel 14 of the rotor shaft. This allows the liquid gas cooling medium to flow smoothly inside the rotor shaft and optimizes the fluid dynamics, thereby improving the overall system efficiency and performance.

[0036] Furthermore, the top cover 3 and the hollow rotor shaft 13 are sealed by a sealing ring 6, which is used to maintain a negative pressure environment inside the housing.

[0037] It should be noted that the top cover 3 and the hollow rotor shaft 13 are sealed by a sealing ring 6. The main function of this sealing ring 6 is to maintain a negative pressure environment within the housing, ensuring the normal operation of the system. In selecting the sealing ring 6, a graphite dynamic sealing ring 6 is preferred. The graphite dynamic sealing ring 6 has excellent wear resistance and corrosion resistance, and can maintain good sealing performance under harsh environments such as high temperature and high pressure, effectively preventing leakage. Furthermore, the automatic compensation performance of the graphite dynamic sealing ring 6 allows it to automatically adjust the contact pressure with the hollow rotor shaft 13 during rotor operation, ensuring the stability of the sealing effect.

[0038] Furthermore, the end of the inlet pipe away from the inlet pipe 8 is connected to the liquefied gas tank 1, and the outer wall of the liquefied gas tank 1 is provided with a heat insulation component; the heat insulation component maintains the temperature stability of the liquefied gas inside the tank and prevents fluctuations in the performance of the liquefied gas caused by changes in the external ambient temperature.

[0039] Furthermore, an electromagnetic valve 2 is installed on the intake pipe. The opening and closing state of the electromagnetic valve 2 is controlled by a control program. The control program can flexibly control the opening and closing state of the electromagnetic valve 2 according to actual needs, thereby achieving effective regulation of the airflow in the intake pipe.

[0040] Furthermore, a stator water jacket 15 is provided on the outer wall of the motor stator 12. The stator water jacket 15 is used to cool the stator. The main function and role of the stator water jacket 15 is to effectively and continuously cool the motor stator 12 through the cooling water medium circulating inside it. By setting up the stator water jacket 15, excess heat generated by the stator during operation can be removed in time, thereby maintaining the overall operating temperature of the motor within a reasonable range, ensuring stable operation of the motor and extending its service life.

[0041] Furthermore, the housing is connected to a vacuum pump via a pipeline, which is used to maintain a vacuum state on the inner wall of the housing. The vacuum pump can effectively draw in air and other gases from inside the housing, preventing them from affecting the internal environment of the housing.

[0042] It should be noted that a top cover 3 penetrates the end of the hollow rotor shaft 13. This top cover 3 is movably connected to the housing to fix the position of the air inlet pipe, and together with the inlet pipe 8, the pressure ring 5, and the finned ring 10, forms the internal flow channel 14 of the rotor shaft. The finned ring 10 is fixed by an interference fit and prevented from moving by the pressure ring 5. The top cover 3 and the hollow rotor shaft 13 are sealed by a sealing ring 6. The sealing ring 6 is usually a graphite dynamic sealing ring 6 to ensure that the negative pressure environment inside the housing is not disrupted. The end of the air inlet pipe away from the inlet pipe 8 is connected to the liquefied gas tank 1. The tank body is equipped with insulation to maintain the temperature of the liquefied gas. A solenoid valve 2 is also installed on the air inlet pipe. The opening and closing state of the solenoid valve 2 is adjusted in real time by a control program to dynamically inject liquefied gas according to the rotor temperature. Meanwhile, the outer wall of the motor stator 12 is equipped with a stator water jacket 15 for auxiliary cooling of the stator. The housing is connected to the vacuum pump through a pipeline to maintain the vacuum state inside the housing to reduce wind loss and improve system efficiency. The entire device absorbs heat through liquid-gas-liquid phase change, which has high heat exchange efficiency and is environmentally friendly, enabling long-term stable operation of flywheel energy storage.

[0043] Working principle: A hole is drilled at the end of the flywheel motor rotor 11, and the liquid gas medium is inserted into the hollow shaft of the motor rotor 11 from the top through the inlet tube 8. The inlet tube 8 is welded to the top cover 3, and the top cover 3 is bolted to the top of the unit sealing housing 20 to keep the inlet tube 8 inside the hollow shaft 13 of the rotor fixed.

[0044] A finned ring 10 is embedded inside the hollow rotor shaft 13. The finned ring 10 and the hollow rotor shaft 13 are interference-fitted, and a pressure ring 5 is used to fix the top of the hollow shaft to prevent the finned ring 10 from moving. The top cover 3, the indentation tube 8, the pressure ring 5, and the finned ring 10 form the internal flow channel 14 of the rotor shaft. A graphite dynamic sealing ring 6 is used to seal between the top cover 3 and the hollow shaft of the motor rotor 11 to maintain a negative pressure environment inside the sealing housing 20.

[0045] The liquefied gas tank 1 is insulated on the outside and is used to hold liquefied gas. It also self-pressurizes and delivers liquefied air to the outside while expelling excess gas from the inside. It is connected to a solenoid valve 2 via a pipeline, which in turn is connected to an inlet pipe 8 via a pipeline. When the temperature of the hollow shaft of the motor rotor 11 exceeds a certain level, the solenoid valve 2 is opened via a control program, allowing the liquefied gas in the tank 1 to flow into the inlet pipe 8 and then into the rotor shaft's internal flow channel 14. There, it absorbs heat conducted from the hollow shaft 13 to the finned ring 10, causing the liquefied gas to vaporize and exit through the gas outlet 4 on the top cover 3. The fins on the finned ring 10 prevent the liquid from flowing out under centrifugal force during rotor rotation and increase the heat exchange area between the liquefied gas and the vaporized gas.

[0046] The liquefied gas in liquefied gas tank 1 can be liquid nitrogen, liquefied carbon dioxide, or other working fluids with boiling points lower than room temperature and which are environmentally friendly.

[0047] An upper protective bearing 7 is mounted on the upper part of the hollow rotor shaft 13, and an upper radial bearing 9 is mounted below the upper protective bearing 7. The motor rotor 11 is then mounted downwards. The motor stator 12 is mounted radially outwards from the motor rotor 11, and the motor stator 12 is cooled by a stator water jacket 15. The flywheel body 16 is located at the lower part of the hollow rotor shaft 13 and is rigidly connected by bolts.

[0048] The lower radial position of the flywheel body 16 and the sealing housing are equipped with a thrust bearing 18 to support the weight of the flywheel body 16. The lower radial bearing 17 and the lower protective bearing 19 are sequentially assembled on the lower part of the flywheel body 16.

[0049] Finally, it should be noted that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways as long as they do not depart from the scope of the present invention.

Claims

1. A flywheel energy storage device with rotor liquid gas cooling, characterized in that: include, A housing, wherein a motor and a flywheel body (16) connected to the motor are disposed within the housing; The motor includes a rotor and a stator. A hollow rotor shaft (13) passes through the central shaft of the rotor. An inlet tube (8) is provided on the inner wall of the hollow rotor shaft (13). The end of the inlet tube (8) is connected to the air inlet pipe. An air outlet is provided at the end of the hollow rotor shaft (13). The liquid gas medium flows into the inlet pipe through the inlet pipe (8) and flows out through the outlet hole through the hollow shaft (13) of the rotor, which can dissipate the heat accumulated during the operation of the flywheel rotor.

2. The flywheel energy storage device with rotor liquid gas cooling according to claim 1, characterized in that: The inner wall of the hollow rotor shaft (13) is provided with a finned ring (10). The end of the inlet tube (8) away from the outlet hole extends into the bottom of the hollow rotor shaft (13), so that the liquid gas medium enters the bottom of the hollow rotor shaft (13) along the inlet tube (8) and moves upward from the bottom of the hollow rotor shaft (13) through the finned ring (10) to the outlet hole for discharge. The finned ring (10) is used to prevent the liquid from flowing out under the action of centrifugal force. The finned ring (10) can increase the heat exchange area between the liquefied gas and the vaporized gas.

3. The rotor-cooled flywheel energy storage device according to claim 2, characterized in that: The top cover (3) passes through the end of the hollow shaft (13) of the rotor, and the top cover (3) is movably connected to the housing; The top cover (3) is used to keep the position of the air intake pipe inside the hollow shaft (13) of the rotor fixed.

4. The rotor-cooled flywheel energy storage device according to claim 3, characterized in that: The fin ring (10) and the hollow rotor shaft (13) are interference fit, and the top of the hollow rotor shaft (13) is provided with a pressure ring (5) to prevent the fin ring (10) from moving.

5. The rotor-cooled flywheel energy storage device according to claim 4, characterized in that: The top cover (3), the in-feed tube (8), the pressure ring (5), and the finned ring (10) together form the inner flow channel (14) of the rotor shaft.

6. The flywheel energy storage device with rotor liquid gas cooling according to claim 5, characterized in that: The top cover (3) and the hollow rotor shaft (13) are sealed by a sealing ring (6), which is used to maintain a negative pressure environment inside the housing.

7. The rotor-cooled flywheel energy storage device according to claim 6, characterized in that: The end of the air inlet pipe away from the inlet pipe (8) is connected to the liquefied gas tank (1), and the outer wall of the liquefied gas tank (1) is provided with a heat insulation component.

8. The rotor-cooled flywheel energy storage device according to claim 7, characterized in that: The intake pipe is equipped with a solenoid valve (2), and the opening and closing state of the solenoid valve (2) is controlled by a control program.

9. The rotor-cooled flywheel energy storage device according to claim 8, characterized in that: The stator (12) of the motor is provided with a stator water jacket (15) on its outer wall, which is used to cool the stator.

10. The rotor-cooled flywheel energy storage device according to claim 9, characterized in that: The housing is connected to a vacuum pump via a pipeline, and the vacuum pump is used to maintain a vacuum state on the inner wall of the housing.

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