A flywheel energy storage system and its cooling method

Abstract

The present invention belongs to the technical field of flywheel energy storage, and discloses a flywheel energy storage system and a cooling method thereof, which include a rotor assembly and a housing. The rotor assembly includes a rotating shaft and a rotor. The rotor is coaxially installed on the rotating shaft. The upper end of the rotating shaft penetrates through the housing and is in sealed and rotational connection with the housing. The lower end of the rotating shaft is rotationally connected with the housing. The rotor is located in the housing. Upper and lower water collecting rings are respectively provided at the upper and lower edges of the rotor. A plurality of water cooling pipes are evenly arranged along the circumferential direction of the rotor on the outer wall surface of the rotor. The upper end of the water cooling pipe is communicated with the upper water collecting ring, and the lower end is communicated with the lower water collecting ring. A first water channel and a second water channel are provided in the rotating shaft. The lower end of the first water channel extends below the rotor and is communicated with the lower water collecting ring through a first water collecting pipe. The lower end of the second water channel extends above the rotor and is communicated with the upper water collecting ring through a second water collecting pipe. The present invention is provided with a cooling structure, so that during the operation of the flywheel, heat can be well taken out of the flywheel chamber.

Description

Technical Field

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

[0002] The flywheel energy storage system is an advanced physical energy storage technology that uses an electric motor to drive a flywheel to rotate at a high speed to store energy, and releases energy by driving a generator to generate electricity when needed. The working principle of the flywheel energy storage system is based on the law of conservation of energy and the kinetic energy theorem, and realizes the mutual conversion and storage between electrical energy and mechanical energy through an electric / generator reversible bidirectional motor.

[0003] Remarkable breakthroughs have been made in the flywheel energy storage technology in aspects such as electric / generator reversible bidirectional motors, high-speed rotating body design, and control systems. The flywheel energy storage system is applicable to the field of power systems and is used to stabilize power and adjust peak and valley loads. In the power industry, in order to improve the electro-electric conversion efficiency of flywheel energy storage, the rotor and the motor share a chamber, and the chamber is in a vacuum state. The vacuum state can reduce the heat generated by the friction between the rotor and the air and lower the efficiency of the flywheel. Although this can improve the efficiency of the flywheel energy storage system, the heat generated by the motor coil in the chamber and the heat generated during the rotation of the rotor cannot be effectively controlled. When the operation time is relatively long, the heat in the chamber cannot be dissipated, and the surface temperature of the flywheel housing is relatively high, seriously affecting the safe operation of the equipment. Summary of the Invention

[0004] To solve the problems existing in the prior art, the object of the present invention is to provide a flywheel energy storage system and a cooling method thereof. The present invention is provided with a cooling structure, so that during the operation of the flywheel, heat can be well taken out of the flywheel chamber.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A flywheel energy storage system includes a rotor assembly and a housing. The rotor assembly includes a rotating shaft and a rotor. The rotor is coaxially installed on the rotating shaft. The upper end of the rotating shaft penetrates through the housing and is in sealed and rotational connection with the housing. The lower end of the rotating shaft is in rotational connection with the housing. The rotor is located in the housing. An upper water collecting ring is provided at the upper side edge of the rotor, and a lower water collecting ring is provided at the lower side edge of the rotor. A plurality of water cooling pipes are uniformly arranged on the outer wall surface of the rotor along the circumferential direction of the rotor. The upper end of the water cooling pipe is communicated with the upper water collecting ring, and the lower end of the water cooling pipe is communicated with the lower water collecting ring. A first water channel and a second water channel are provided in the rotating shaft. The upper ends of the first water channel and the second water channel extend to the upper end surface of the rotating shaft. The lower end of the first water channel extends below the rotor. The lower end of the first water channel is communicated with the lower water collecting ring through a first water collecting pipe. The lower end of the second water channel extends above the rotor. The second water channel is communicated with the upper water collecting ring through a second water collecting pipe.

[0007] Preferably, the lower end of the first water channel communicates with the lower water collecting ring through at least two first water collecting pipes. One end of all the first water collecting pipes communicates with the lower end of the first water channel, and the other ends of all the first water collecting pipes are evenly distributed in the circumferential direction of the lower water collecting ring and communicate with the lower water collecting ring.

[0008] Preferably, the first water channel is arranged along the axis of the rotating shaft.

[0009] Preferably, in the rotating shaft, at least two second water channels are evenly opened in the circumferential direction of the first water channel. The axes of all the second water channels are parallel to the axis of the rotating shaft. The lower end of each second water channel communicates with the upper water collecting ring through a second water collecting pipe, and the connection points of all the second water collecting pipes with the upper water collecting ring are evenly distributed in the circumferential direction of the upper water collecting ring.

[0010] Preferably, the connection point of the first water collecting pipe with the lower water collecting ring is located at the midpoint between the connection points of two adjacent water cooling pipes with the lower water collecting ring.

[0011] Preferably, the connection point of the second water collecting pipe with the upper water collecting ring is located at the midpoint between the connection points of two adjacent water cooling pipes with the upper water collecting ring.

[0012] Preferably, both the second water collecting pipe and the first water collecting pipe are straight pipes. The axis of the second water collecting pipe intersects with the axis of the rotating shaft, and the axis of the first water collecting pipe intersects with the axis of the rotating shaft.

[0013] Preferably, the rotor is cylindrical in shape, the upper water collecting ring and the lower water collecting ring are circular in shape. The upper water collecting ring is clamped on the upper side edge of the rotor, and the lower water collecting ring is clamped on the lower side edge of the rotor.

[0014] Preferably, the flywheel energy storage system of the present invention further includes a motor, which is connected to the upper end of the rotating shaft and is located outside the housing. The motor includes a motor or a generator.

[0015] The present invention also provides a cooling method for the flywheel energy storage system as described above, including the following process:

[0016] Cooling water is introduced into the first water channel. The cooling water in the first water channel sequentially flows through the first water collecting pipe, the lower water collecting ring, the water cooling pipe, the upper water collecting ring, the second water collecting pipe and the second water channel to realize the cooling of the rotating shaft and the rotor.

[0017] The present invention has the following beneficial effects:

[0018] In the flywheel energy storage system of the present invention, the cooling structure can be set to cool the rotating shaft of the rotor assembly and the rotating shaft. Specifically, the cooling structure includes a first water channel and a second water channel provided in the rotating shaft. When the cooling water flows in the first water channel and the second water channel, the cooling of the rotating shaft can be achieved. The cooling structure also includes an upper water collecting ring, a lower water collecting ring and a water cooling pipe. Among them, the lower water collecting ring can distribute the cooling water provided by the first water channel through the first water collecting pipe to each water cooling pipe. As the main structure for cooling the rotor, the water cooling pipe can absorb the heat of the rotor and the space around the rotor. The upper water collecting ring can collect the cooling water after heat exchange of each water cooling pipe and discharge it into the second water channel through the second water collecting pipe, thus realizing the flow of the cooling water in the cooling structure. The lower end of the first water channel extends below the rotor, and the lower water collecting ring is arranged on the lower side edge of the rotor, so the first water collecting pipe is inclined; the lower end of the second water channel extends above the rotor, and the upper water collecting ring is arranged on the upper side edge of the rotor, so the second water collecting pipe is inclined; since both the first water collecting pipe and the second water collecting pipe are inclined, when the rotor rotates, the first water collecting pipe can cool the area below the lower surface of the rotor, and the second water collecting pipe can cool the area above the upper surface of the rotor. Therefore, in the flywheel energy storage system of the present invention, effective cooling of the rotor can be achieved. At the same time, in the present invention, the upper water collecting ring, the water cooling pipe and the lower water collecting ring form a squirrel-cage structure wrapped outside the rotor, and at the same time, the first water collecting pipe and the second water collecting pipe are used for inclined traction, so the strength of the cooling structure in the flywheel energy storage system of the present invention is guaranteed and can withstand a higher rotational speed. From the structure of the flywheel energy storage system of the present invention, it can be seen that the present invention does not damage the structure of the rotor, and the rotor structure is complete. Therefore, the improvement of the present invention does not affect the strength of the rotor. Although the first water channel and the second water channel are added to the rotating shaft in the present invention, since the first water channel and the second water channel are close to the axis of the rotating shaft, the influence on the strength of the rotating shaft is small. In summary, the present invention effectively transports the heat in the flywheel chamber (i.e., the inner cavity of the housing) to the outside world without affecting the overall structure and strength of the rotor and with the least influence on the strength of the rotating shaft, and keeps the temperature in the flywheel chamber at a preset temperature, so that the rotor assembly operates in a suitable environment, on the one hand, ensuring the charge and discharge efficiency of the rotor assembly, and on the other hand, ensuring the safe operation of the entire flywheel energy storage system equipment. Brief Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0020] Figure 1 This is the overall structural diagram of the flywheel energy storage system in an embodiment of the present invention;

[0021] Figure 2 is Figure 1 the internal structural diagram of the flywheel energy storage system in the illustrated embodiment;

[0022] Figure 3 This is the internal structural diagram of the flywheel energy storage system in another embodiment of the present invention;

[0023] Wherein: 1 is a housing; 2 is a rotor; 3 is a motor; 4 is a rotating shaft; 5 is a first water channel; 501 is a first water channel interface; 6 is a second water channel; 601 is a second water channel interface; 7 is a second water collecting pipe; 8 is an upper water collecting ring; 9 is a water cooling pipe; 10 is a lower water collecting ring; 11 is a first water collecting pipe. Detailed implementation manners

[0024] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Generally, the components described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of the present invention provided in the accompanying drawings here is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0025] Refer to Figures 1-3, in this embodiment of the flywheel energy storage system, it includes a rotor assembly and a housing 1. The rotor assembly includes a rotating shaft 4 and a rotor 2. The rotor 2 is coaxially installed on the rotating shaft 4. The upper end of the rotating shaft 4 penetrates through the housing 1 and is hermetically and rotatably connected to the housing 1. In this way, a sealed chamber (also called a flywheel chamber) is formed inside the housing 1. The inside of the housing 1 is evacuated to make the inner cavity of the housing 1 in a vacuum state. The lower end of the rotating shaft 4 is rotatably connected to the housing 1. The rotor 2 is located in the housing 1. An upper water collecting ring 8 is provided at the upper side edge of the rotor 2, and a lower water collecting ring 10 is provided at the lower side edge of the rotor 2. A plurality of water cooling pipes 9 are evenly arranged on the outer wall surface of the rotor 2 along the circumferential direction of the rotor 2. The upper end of the water cooling pipe 9 is communicated with the upper water collecting ring 8, and the lower end of the water cooling pipe 9 is communicated with the lower water collecting ring 10. In this way, the lower water collecting ring 10, the upper water collecting ring 8 and the water cooling pipes 9 together form a squirrel-cage structure. This structure has a high bearing capacity and high stability, thus ensuring the stability of the overall structure of the flywheel energy storage system of the present invention; a first water channel 5 and a second water channel 6 are provided in the rotating shaft 4. The upper ends of the first water channel 5 and the second water channel 6 extend to the upper end surface of the rotating shaft 4. The lower end of the first water channel 5 extends below the rotor 2. The lower end of the first water channel 5 is communicated with the lower water collecting ring 10 through a first water collecting pipe 11. At this time, the first water collecting pipe 11 is in an inclined state. The lower end of the second water channel 6 extends above the rotor 2. The second water channel 6 is communicated with the upper water collecting ring 8 through a second water collecting pipe 7. At this time, the second water collecting pipe 7 is in an inclined state. In the flywheel energy storage system of this embodiment, although the inside of the housing 1 is in a vacuum, it is actually impossible to achieve a complete vacuum in practice. Therefore, there will be more or less some gas in the inner cavity of the housing 1. In this embodiment, both the first water collecting pipe 11 and the second water collecting pipe 7 are in an inclined state. Then, when the rotor 2 rotates, the first water collecting pipe 11 rotates below the lower surface of the rotor 2, and can cool the area below the lower surface of the rotor 2. The second water collecting pipe 7 rotates above the upper surface of the rotor 2, and can cool the area above the upper surface of the rotor 2, thereby realizing the cooling of the upper surface part and the lower surface part of the rotor 2. In addition, both the first water collecting pipe 11 and the second water collecting pipe 7 are in an inclined state, which helps the migration of bubbles during cooling, and finally makes the bubbles discharged, greatly reducing the probability of the formation of air plugs and improving the cooling effect. In addition, in this embodiment, the above-mentioned squirrel-cage structure can be pulled through the first water collecting pipe 11 and the second water collecting pipe 7 to ensure the strength, integrity and stability of the entire cooling structure. In this embodiment, since both the first water channel 5 and the second water channel 6 are arranged inside the rotating shaft 4, therefore, when the cooling water flows in the first water channel 5 and the second water channel 6, the rotating shaft 4 can be cooled. And because the present invention can cool the rotating shaft 4, the heat in the rotor 2 (mainly the part of the rotor 2 close to the rotating shaft 4 at the center) can be transferred to the rotating shaft 4 by heat transfer. Then, the present invention can also indirectly realize the cooling of the inside of the center of the rotor 2 by using the first water channel 5 and the second water channel 6.Moreover, under this embodiment, the lower water collecting ring 10, the upper water collecting ring 8 and the water cooling pipe 9 as a whole form a squirrel-cage structure, and this squirrel-cage structure is located on the outer edge of the rotor 2 as a whole. Therefore, it can cool down the outer edge of the rotor 2 (especially the side wall part of the rotor 2). It can be seen from the above solution of this embodiment that this embodiment can cool down the central part, the outer edge part, the upper surface part and the lower surface part of the rotor 2, and has the characteristic of good cooling effect.

[0026] The cooling method of the flywheel energy storage system in the above embodiment of the present invention includes the following process:

[0027] Cooling water is introduced into the first water channel 5. The cooling water in the first water channel 5 flows through the first water collecting pipe 11, the lower water collecting ring 10, the water cooling pipe 9, the upper water collecting ring 8, the second water collecting pipe 7 and the second water channel 6 in sequence. The cooling water entering from the first water channel 5 will flow downwards along the first water channel 5 in the rotating shaft 4 from top to bottom. When it flows to the lower end of the first water channel 5, the cooling water flows into the lower water collecting ring 10 through the first water collecting pipe 11. The cooling water entering the lower water collecting ring 10 is distributed by the lower water collecting ring 10 and then enters the lower ends of the water cooling pipes 9 and flows from bottom to top along the water cooling pipes 9. Then, after the cooling water flows out from the upper ends of the water cooling pipes 9, it enters the upper water collecting ring 8 for collection, and then enters the second water channel 6 through the second water collecting pipe 7. Then, the cooling water flows out along the second water channel 6 in the rotating shaft 4. Through the above process, the cooling and temperature reduction of the rotating shaft 4 and the rotor 2 are realized. Since the cooling water enters the entire cooling structure through the first water channel 5 and flows out through the second water channel 6 after absorbing heat, the temperature of the cooling water in the first water channel 5 is lower than the temperature of the cooling water in the second water channel 6. In the entire cooling structure, along the flow path of the cooling water, the first water collecting pipe 11 is located upstream of the second water collecting pipe 7. Therefore, the temperature of the cooling water in the first water collecting pipe 11 is lower than the temperature of the cooling water in the second water collecting pipe 7.

[0028] As a preferred embodiment of the present invention, in this embodiment, the first water channel 5 is arranged along the axis of the rotating shaft 4. Since the first water channel 5 is coaxial with the rotating shaft 4, the vibration during the rotation of the rotating shaft 4 can be reduced.

[0029] As a preferred embodiment of the present invention, in this embodiment, the lower end of the first water channel 5 is communicated with the lower water collecting ring 10 through at least two first water collecting pipes 11. One end of all the first water collecting pipes 11 is communicated with the lower end of the first water channel 5, and the other ends of all the first water collecting pipes 11 are uniformly distributed in the circumferential direction of the lower water collecting ring 10 and are communicated with the lower water collecting ring 10. The purpose of such a setting is that all the first water collecting pipes 11 are uniformly distributed in the circumferential direction of the rotating shaft 4, and the overall rotation center of all the first water collecting pipes 11 is concentric with the rotating shaft 4, so that the vibration during the rotation of the rotating shaft 4 can be reduced.

[0030] As a preferred embodiment of the present invention, in this embodiment, in the rotating shaft 4, at least two second water channels 6 are evenly arranged in the circumferential direction of the first water channel 5. The axes of all the second water channels 6 are parallel to the axis of the rotating shaft 4. The lower end of each second water channel 6 is communicated with the upper water collecting ring 8 through a second water collecting pipe 7. The connection points of all the second water collecting pipes 7 and the upper water collecting ring 8 are evenly distributed in the circumferential direction of the upper water collecting ring 8. The purpose of such a setting is that all the second water channels 6 are evenly distributed in the circumferential direction of the rotating shaft 4, and the overall rotation center of all the second water channels 6 is concentric with the rotating shaft 4, which can reduce the vibration when the rotating shaft 4 rotates.

[0031] As a preferred embodiment of the present invention, refer to Figure 3 , in this embodiment, the connection point of the first water collecting pipe 11 and the lower water collecting ring 10 is located at the midpoint between the connection points of two adjacent water cooling pipes 9 and the lower water collecting ring 10. The purpose of this structural design is, on the one hand, to prevent the cooling water conveyed by the first water collecting pipe 11 from flowing away from the water cooling pipe 9 closer to the first water collecting pipe 11 first in the lower water collecting ring 10, resulting in uneven distribution of water in the lower water collecting ring 10, and further resulting in asymmetric cooling effect in the circumferential direction of the rotor 2. Since the material used to prepare the rotor 2 has the property of thermal expansion and contraction, the thermal expansion degree of the region with higher temperature on the rotor 2 is greater than that of the region with lower temperature, which will cause the shape of the rotor 2 to be asymmetric, and further cause the eccentricity between the centroid of the rotor 2 and the center of the rotating shaft 4 to increase, and further cause the rotor 2 to rotate unstably at high speed. On the other hand, in the above structure, the water flowing out of the first water collecting pipe 11 will flow into the above two adjacent water cooling pipes 9 at basically the same speed, which ensures that the water temperatures of the cooling water on both sides of each first water collecting pipe 11 are basically symmetric. That is to say, in the squirrel-cage structure, the density distribution of the cooling water is also basically symmetric. Since the eccentricity of the centroid of the rotor 2 will cause the rotor 2 to generate large vibrations when rotating with the rotating shaft 4 during high-speed rotation of the rotor 2, the above structural design of this embodiment greatly reduces the uneven mass distribution of the entire cooling water network (referring to the distribution structure of the cooling water in the squirrel-cage structure, and removing all the pipes in the squirrel-cage structure, the shape of the remaining water is the same as that of the squirrel-cage structure, and the structure of the cooling water at this time is called the cooling water network, and the shape of the cooling water network is also squirrel-cage) caused by the uneven density of the cooling water, resulting in an increase in the eccentricity between the centroid of the overall structure formed by the squirrel-cage structure and the cooling water inside it and the center of the rotating shaft 4, and causing the rotor 2 to rotate unstably at high speed.

[0032] As a preferred embodiment of the present invention, refer to Figure 3, in this embodiment, the connection point between the second water collecting pipe 7 and the upper water collecting ring 8 is located at the midpoint between the connection points of two adjacent water cooling pipes 9 and the upper water collecting ring 8. The functions and purposes of the structural design of this embodiment are the same as those of the connection point between the first water collecting pipe 11 and the lower water collecting ring 10 being located at the midpoint between the connection points of two adjacent water cooling pipes 9 and the lower water collecting ring 10 in the above embodiment, and will not be elaborated here.

[0033] As a preferred embodiment of the present invention, in this embodiment, both the second water collecting pipe 7 and the first water collecting pipe 11 are straight pipes. The axis of the second water collecting pipe 7 intersects the axis of the rotating shaft 4, and the axis of the first water collecting pipe 11 intersects the axis of the rotating shaft 4. In this embodiment, the above designs of the second water collecting pipe 7 and the first water collecting pipe 11 enable the second water collecting pipe 7 and the first water collecting pipe 11 to be mainly subjected to tensile or compressive forces during the rotation of the rotor 2, avoiding bending moments, and further avoiding bending in the rotation plane of the second water collecting pipe 7 and the first water collecting pipe 11 when the rotor 2 rotates at high speed, thereby avoiding causing large additional stresses on the connection points at both ends of the second water collecting pipe 7 and the connection points at both ends of the first water collecting pipe 11, resulting in a reduction in the reliability of the connection points of the second water collecting pipe 7 and the first water collecting pipe 11. Additionally, it is also to avoid increasing the eccentricity between the centroid of the overall structure composed of the second water collecting pipe 7, the first water collecting pipe 11, and the cooling water inside them and the center of the rotating shaft 4, which may cause the rotor 2 to rotate unstably at high speeds.

[0034] As an alternative embodiment of the present invention, in this embodiment, the shape of the rotor 2 is cylindrical. Correspondingly, the shapes of the upper water collecting ring 8 and the lower water collecting ring 10 are circular. The upper water collecting ring 8 is hoop-shaped on the upper side edge of the rotor 2, and the lower water collecting ring 10 is hoop-shaped on the lower side edge of the rotor 2.

[0035] As an alternative embodiment of the present invention, in this embodiment, the surface shapes of the upper water collecting ring 8, the lower water collecting ring 10, and the water cooling pipe 9 in contact with the rotor 2 are set to curved surfaces that are adapted to the shapes of the contact parts with the rotor 2, so as to increase the contact area between the upper water collecting ring 8, the lower water collecting ring 10, and the water cooling pipe 9 and the rotor 2, and further improve the cooling effect on the rotor 2. For example, the side surface of the water cooling pipe 9 facing the side wall of the rotor 2 can be set as a cylindrical surface with the same curvature as the side wall of the rotor 2, so that a surface contact is formed between the water cooling pipe 9 and the side wall of the rotor 2, improving the heat exchange effect.

[0036] As an alternative embodiment of the present invention, referring to Figure 1 , in this embodiment, the flywheel energy storage system of the present invention further includes a motor 3. The motor 3 is connected to the upper end of the rotating shaft 4 and is located outside the housing 1. Among them, the motor 3 can be a motor or a generator.

[0037] Embodiment

[0038] See Figure 3 , in this embodiment, the flywheel energy storage system includes a rotor assembly, a housing 1 and a motor. The rotor assembly includes a rotating shaft 4 and a rotor 2. The rotor 2 is coaxially installed on the rotating shaft 4. The upper end of the rotating shaft 4 penetrates through the housing 1 and is in sealed and rotational connection with the housing 1. The lower end of the rotating shaft 4 is in rotational connection with the housing 1. The rotor 2 is located in the housing 1. An upper water collecting ring 8 is provided at the upper side edge of the rotor 2, and a lower water collecting ring 10 is provided at the lower side edge of the rotor 2. Twelve water cooling pipes 9 are evenly arranged along the circumferential direction of the rotor 2 on the outer wall surface of the rotor 2. The upper end of the water cooling pipe 9 is communicated with the upper water collecting ring 8, and the lower end of the water cooling pipe 9 is communicated with the lower water collecting ring 10. A first water channel 5 and two second water channels 6 are provided in the rotating shaft 4. The upper ends of the first water channel 5 and the second water channels 6 extend to the upper end surface of the rotating shaft 4. The first water channel 5 is arranged along the axis of the rotating shaft 4. The two second water channels 6 are symmetrically distributed on both sides of the first water channel 5. The axis of the second water channel 6 is parallel to the axis of the rotating shaft 4. The lower end of the first water channel 5 extends below the rotor 2. The lower end of the first water channel 5 is communicated with the lower water collecting ring 10 through two first water collecting pipes 11. The two first water collecting pipes 11 are symmetrically distributed on both sides of the axis of the rotating shaft 4. The connection points of the two first water collecting pipes 11 with the lower water collecting ring 10 are symmetrically distributed in the circumferential direction of the lower water collecting ring 10. The lower ends of the second water channels 6 extend above the rotor 2. The second water channels 6 are communicated with the upper water collecting ring 8 through two second water collecting pipes 7. The two second water collecting pipes 7 are symmetrically distributed on both sides of the axis of the rotating shaft 4. The connection points of the two second water collecting pipes 7 with the upper water collecting ring 8 are symmetrically distributed in the circumferential direction of the upper water collecting ring 8. The connection point of the first water collecting pipe 11 with the lower water collecting ring 10 is located at the midpoint between the connection points of two adjacent water cooling pipes 9 with the lower water collecting ring 10. The connection point of the second water collecting pipe 7 with the upper water collecting ring 8 is located at the midpoint between the connection points of two adjacent water cooling pipes 9 with the upper water collecting ring 8. Along the axial direction of the rotating shaft 4, the included angle between the second water collecting pipe 7 and the first water collecting pipe 11 is 90°. Both the second water collecting pipe 7 and the first water collecting pipe 11 adopt straight pipes. The axis of the second water collecting pipe 7 intersects with the axis of the rotating shaft 4, and the axis of the first water collecting pipe 11 intersects with the axis of the rotating shaft 4. The shape of the rotor 2 is cylindrical, and the corresponding shapes of the upper water collecting ring 8 and the lower water collecting ring 10 are circular. The upper water collecting ring 8 is buckled on the upper side edge of the rotor 2, and the lower water collecting ring 10 is buckled on the lower side edge of the rotor 2. The motor is connected to the upper end of the rotating shaft 4 and is located outside the housing 1. Correspondingly, a first water channel interface 501 is provided at the water inlet end of the first water channel 5 in this embodiment, and a second water channel interface 601 is provided at the water outlet end of the second water channel 6; since the temperature of the cooling water in the first water channel 5 is lower than the temperature of the cooling water in the second water channel 6, therefore, the temperature of the cooling water in the first water channel interface 501 is lower than the temperature of the cooling water in the second water channel interface 601.

[0039] The cooling method of the flywheel energy storage system in this embodiment includes the following processes:

[0040] Cooling water is introduced into the first water channel 5. The cooling water in the first water channel 5 is divided into two paths at the lower end of the first water channel 5 and is synchronously fed into the lower water collecting ring 10 through two first water collecting pipes 11 respectively. The cooling water in the lower water collecting ring 10 flows symmetrically on both sides of two connection points (i.e., the connection points of the two first water collecting pipes 11 and the lower water collecting ring 10). Since the two connection points (i.e., the connection points of the two first water collecting pipes 11 and the lower water collecting ring 10) are symmetrical, the temperature of the cooling water in the lower water collecting ring 10 is also symmetrical (i.e., symmetrical about the plane where the axis of the two first water collecting pipes 11 and the axis of the rotating shaft 4 are located). Then it flows upward along the water cooling pipe 9 into the upper water collecting ring 8. Since the temperature of the cooling water in the lower water collecting ring 10 is symmetrical, and the connection points of the first water collecting pipes 11 and the lower water collecting ring 10 are located at the midpoints of the connection points of two adjacent water cooling pipes 9 and the lower water collecting ring 10, and the connection points of the second water collecting pipes 7 and the upper water collecting ring 8 are located at the midpoints of the connection points of two adjacent water cooling pipes 9 and the upper water collecting ring 8, the temperature of the cooling water in the upper water collecting ring 8 is also symmetrical (i.e., symmetrical about the plane where the axis of the two first water collecting pipes 11 and the axis of the rotating shaft 4 are located). The cooling water in the upper water collecting ring 8 then is respectively transported to the two second water channels 6 through the two second water collecting pipes 7 and is discharged from the second water channel 6. Since along the axial direction of the rotating shaft 4, the included angle between the second water collecting pipe 7 and the first water collecting pipe 11 is 90°, for the upper water collecting ring 8, at the positions connected to the two second water collecting pipes 7, the temperature of the cooling water is basically the same, so the temperature of the cooling water in the two second water collecting pipes 7 is the same. It can be seen from the above that the design structure of this embodiment greatly reduces the eccentricity degree of the flywheel energy storage system during the rotation process, which is beneficial to the stable operation of the rotor assembly and the cooling structure at high speed.

[0041] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications or equivalent replacements can still be made to the specific implementation manners of the present invention, and any modification or equivalent replacement without departing from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A flywheel energy storage system, characterized in that: The invention comprises a rotor assembly and a housing (1), wherein the rotor assembly comprises a rotating shaft (4) and a rotor (2), wherein the rotor (2) is coaxially mounted on the rotating shaft (4), wherein the upper end of the rotating shaft (4) penetrates the housing (1) and is sealed and rotatably connected to the housing (1), wherein the lower end of the rotating shaft (4) is rotatably connected to the housing (1), and the rotor (2) is located in the housing (1), wherein an upper water collecting ring (8) is provided on the upper edge of the rotor (2), and a lower water collecting ring (10) is provided on the lower edge of the rotor (2), and wherein a plurality of water cooling tubes (9) are evenly arranged on the outer wall surface of the rotor (2) along the circumference of the rotor (2), wherein the upper ends of the water cooling tubes (9) are connected to the upper water collecting ring (8) and the lower edge of the rotor (2) is connected to the lower edge of the rotor (2). The lower end of the water cooling pipe (9) is connected to the lower water collecting ring (10); a first water channel (5) and a second water channel (6) are provided in the rotating shaft (4); the upper end of the first water channel (5) and the upper end of the second water channel (6) extend to the upper end surface of the rotating shaft (4); the lower end of the first water channel (5) extends to the bottom of the rotor (2); the lower end of the first water channel (5) is connected to the lower water collecting ring (10) through a first water collecting pipe (11); the lower end of the second water channel (6) extends to the top of the rotor (2); the second water channel (6) is connected to the upper water collecting ring (8) through a second water collecting pipe (7); The second water collecting pipe (7) and the first water collecting pipe (11) are both straight pipes; the axis of the second water collecting pipe (7) intersects with the axis of the rotating shaft (4); and the axis of the first water collecting pipe (11) intersects with the axis of the rotating shaft (4).

2. A flywheel energy storage system according to claim 1, characterized in that: The lower end of the first water channel (5) is connected to the lower water collecting ring (10) via at least two first water collecting pipes (11), one end of all the first water collecting pipes (11) is connected to the lower end of the first water channel (5), and the other ends of all the first water collecting pipes (11) are evenly distributed in the circumferential direction of the lower water collecting ring (10) and are connected to the lower water collecting ring (10).

3. A flywheel energy storage system according to claim 1, characterized in that: The first water channel (5) is arranged along the axis of the rotating shaft (4).

4. A flywheel energy storage system according to claim 3, characterized in that: In the rotating shaft (4), at least two second water channels (6) are evenly arranged in the circumferential direction of the first water channel (5), the axes of all the second water channels (6) are parallel to the axis of the rotating shaft (4), the lower end of each second water channel (6) is connected to the upper water collecting ring (8) through a second water collecting pipe (7), and the connection points of all the second water collecting pipes (7) and the upper water collecting ring (8) are evenly distributed in the circumferential direction of the upper water collecting ring (8).

5. A flywheel energy storage system according to claim 1, characterized in that: The connection point between the first water collecting pipe (11) and the lower water collecting ring (10) is located at the midpoint of the connection points between two adjacent water cooling pipes (9) and the lower water collecting ring (10).

6. A flywheel energy storage system according to claim 1, characterized in that: The connection point between the second water collecting pipe (7) and the upper water collecting ring (8) is located at the midpoint of the connection points between two adjacent water cooling pipes (9) and the upper water collecting ring (8).

7. A flywheel energy storage system according to claim 1, characterized in that: The rotor (2) is cylindrical in shape, the upper water collecting ring (8) and the lower water collecting ring (10) are circular in shape, the upper water collecting ring (8) is clamped on the upper edge of the rotor (2), and the lower water collecting ring (10) is clamped on the lower edge of the rotor (2).

8. A flywheel energy storage system according to claim 1, characterized in that: It also includes a motor (3), which is connected to the upper end of the rotating shaft (4) and is located outside the housing (1), and the motor (3) includes an electric motor or a generator.

9. The cooling method of the flywheel energy storage system according to any one of claims 1 to 8, characterized in that: The process includes the following: Cooling water is introduced into the first water channel (5), and the cooling water in the first water channel (5) flows sequentially through the first water collecting pipe (11), the lower water collecting ring (10), the water cooling pipe (9), the upper water collecting ring (8), the second water collecting pipe (7) and the second water channel (6), thereby cooling the rotating shaft (4) and the rotor (2).

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