Flywheel energy storage system and cooling method thereof

Abstract

The invention belongs to the technical field of flywheel energy storage, and discloses a flywheel energy storage system and a cooling method thereof.The flywheel energy storage system comprises a rotor assembly and a shell, the rotor assembly comprises 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 shell and is in sealed and rotating connection with the shell, the lower end of the rotating shaft is in rotating connection with the shell, and the rotor is located in the shell; the upper and lower edges of the rotor are respectively provided with an upper water collecting ring and a lower water collecting ring, the outer wall surface of the rotor is uniformly provided with a plurality of water cooling pipes along the circumferential direction of the rotor, the upper ends of the water cooling pipes are communicated with the upper water collecting ring, and the lower ends are communicated with the lower water collecting ring; a first water channel and a second water channel are arranged in the rotating shaft, the lower end of the first water channel extends to the position below the rotor and communicates with the lower water collecting ring through a first water collecting pipe, and the lower end of the second water channel extends to the position above the rotor and communicates with the upper water collecting ring through a second water collecting pipe. The cooling structure is arranged, so that heat can be well brought out of the flywheel cavity in the running process of the flywheel.

Description

Technical Field

[0001] The invention belongs to the technical field of flywheel energy storage, and in particular 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 high speed to store energy, and releases energy when needed by driving a generator to generate electricity through the flywheel. The working principle of the flywheel energy storage system is based on the law of conservation of energy and the law of kinetic energy, and realizes the mutual conversion and storage between electrical energy and mechanical energy through an electric / generating reciprocal bidirectional motor.

[0003] Flywheel energy storage technology has made significant breakthroughs in electric / generator reciprocal bidirectional motors, high-speed rotating body design, and control systems. Flywheel energy storage systems are applicable to the field of power systems and are used to stabilize electricity and shift peaks and fill valleys. In the power industry, in order to improve the electric-to-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 frictional heat generated by the rotor and the air, and reduce 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, resulting in the inability to dissipate the heat in the chamber when the operation time is long, and the surface temperature of the flywheel shell is high, which seriously affects the safe operation of the equipment. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a flywheel energy storage system and a cooling method thereof. The present invention sets up a cooling structure so that the flywheel can effectively carry the heat out of the flywheel chamber during operation.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows: A flywheel energy storage system comprises a rotor assembly and a shell. The rotor assembly comprises a rotating shaft and a rotor. The rotor is coaxially mounted on the rotating shaft. The upper end of the rotating shaft penetrates the shell and is sealed and rotatably connected to the shell. The lower end of the rotating shaft is rotatably connected to the shell. The rotor is in the shell. An upper water collecting ring is provided on the upper edge of the rotor. A lower water collecting ring is provided on the lower edge of the rotor. A plurality of water cooling tubes are evenly provided on the outer wall surface of the rotor along the circumference of the rotor. The upper ends of the water cooling tubes are communicated with the upper water collecting ring, and the lower ends of the water cooling tubes are 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 upper ends of the second water channel extend to the upper end surface of the rotating shaft, and the lower end of the first water channel extends to the bottom of the rotor. The lower end of the first water channel is communicated with the lower water collecting ring through a first water collecting pipe, and the lower end of the second water channel extends to the top of the rotor. The second water channel is communicated with the upper water collecting ring through a second water collecting pipe.

[0006] Preferably, the lower end of the first water channel is connected to the lower water collecting ring through at least two first water collecting pipes, one end of all the first water collecting pipes is connected to the lower end of the first water channel, and the other ends of all the first water collecting pipes are evenly distributed in the circumference of the lower water collecting ring and connected to the lower water collecting ring.

[0007] Preferably, the first water channel is arranged along the axis of the rotating shaft.

[0008] Preferably, in the rotating shaft, at least two second water channels are evenly opened in the circumference 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 is connected to the upper water collecting ring through a second water collecting pipe, and the connection points between all the second water collecting pipes and the upper water collecting ring are evenly distributed in the circumference of the upper water collecting ring.

[0009] Preferably, the connection point between the first water collecting pipe and the lower water collecting ring is located at the midpoint of the connection points between two adjacent water cooling pipes and the lower water collecting ring.

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

[0011] Preferably, the second water collecting pipe and the first water collecting pipe are both 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.

[0012] 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 hooped on the upper edge of the rotor, and the lower water collecting ring is hooped on the lower edge of the rotor.

[0013] Preferably, the flywheel energy storage system of the present invention further comprises a motor, which is connected to the upper end of the rotating shaft and is located outside the housing, and the motor comprises an electric motor or a generator.

[0014] The present invention also provides a cooling method for the flywheel energy storage system as described above, comprising the following process: Cooling water is introduced into the first water channel, and the cooling water in the first water channel 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 in sequence to cool the rotating shaft and the rotor.

[0015] The present invention has the following beneficial effects: In the flywheel energy storage system of the present invention, by setting up a cooling structure, the rotating shaft of the rotor assembly and the rotating shaft can be cooled. Specifically, the cooling structure includes a first water channel and a second water channel arranged in the rotating shaft. When the cooling water flows in the first water channel and the second water channel, the rotating shaft can be cooled; the cooling structure also includes an upper water collecting ring, a lower water collecting ring and a water cooling pipe, wherein 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, and the water cooling pipe, as the main structure for cooling the rotor, can absorb the heat of the rotor and the space around the rotor, and the upper water collecting ring can collect the cooling water after heat exchange in each water cooling pipe and discharge it to the second water channel through the second water collecting pipe, thereby realizing the flow of cooling water in the cooling structure. The lower end of the first water channel extends to the bottom of the rotor, and the lower water collecting ring is arranged at the lower edge of the rotor, so the first water collecting pipe is inclined; the lower end of the second water channel extends to the top of the rotor, and the upper water collecting ring is arranged at the upper 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, so the flywheel energy storage system of the present invention can achieve effective cooling of the rotor. 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 around the outside of the rotor, and the first water collecting pipe and the second water collecting pipe are used for inclined pulling, so the cooling structure strength in the flywheel energy storage system of the present invention is guaranteed and can withstand higher rotation speeds. It can be seen from the structure of the flywheel energy storage system of the present invention that the present invention does not destroy the structure of the rotor, and the rotor structure is complete, so 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 strength of the rotating shaft is less affected. In summary, the present invention does not affect the overall structure and strength of the rotor and has minimal impact on the strength of the rotating shaft. By adding a cooling structure in the flywheel energy storage system, the heat in the flywheel chamber (i.e., the inner cavity of the shell) is effectively transported to the outside, and the temperature in the flywheel chamber is maintained at a preset temperature, so that the rotor assembly operates in a suitable environment, which ensures the charging and discharging efficiency of the rotor assembly on the one hand, and ensures the safe operation of the entire flywheel energy storage system equipment on the other hand. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 This is an overall structural diagram of a flywheel energy storage system in one embodiment of the present invention; Figure 2 for Figure 1 An internal structural diagram of a flywheel energy storage system in the illustrated embodiment; Figure 3 It is an internal structure diagram of a flywheel energy storage system in another embodiment of the present invention; Among them: 1 is the shell; 2 is the rotor; 3 is the motor; 4 is the rotating shaft; 5 is the first water channel; 501 is the first water channel interface; 6 is the second water channel; 601 is the second water channel interface; 7 is the second water collecting pipe; 8 is the upper water collecting ring; 9 is the water cooling pipe; 10 is the lower water collecting ring; 11 is the first water collecting pipe. DETAILED DESCRIPTION

[0018] In order to make the purpose, 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 in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0019] See also Figure 1-Figure 3The flywheel energy storage system of this embodiment includes a rotor assembly and a shell 1. The rotor assembly includes a rotating shaft 4 and a rotor 2. The rotor 2 is coaxially mounted on the rotating shaft 4. The upper end of the rotating shaft 4 penetrates the shell 1 and is sealed and rotatably connected to the shell 1. In this way, a sealed chamber (also called a flywheel chamber) is formed inside the shell 1. The inside of the shell 1 is evacuated to make the inner cavity of the shell 1 a vacuum state. The lower end of the rotating shaft 4 is rotatably connected to the shell 1. The rotor 2 is in the shell 1. An upper water collecting ring 8 is provided on the upper side edge of the rotor 2, and a lower water collecting ring 10 is provided on the lower side edge of the rotor 2. A plurality of water cooling tubes 9 are evenly provided on the outer wall surface of the rotor 2 along the circumference of the rotor 2. The upper end of the water cooling tube 9 is connected to the upper water collecting ring 8, and the lower end of the water cooling tube 9 is connected to the lower water collecting ring 10. In this way, the lower The water collecting ring 10, the upper water collecting ring 8 and the water cooling tube 9 form a squirrel cage structure as a whole. The structure has high bearing capacity and high stability, thereby 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 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 the 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 to the top of the rotor 2, the second water channel 6 is connected to the upper water collecting ring 8 through the 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 interior of the shell 1 is vacuum, it is impossible to achieve complete vacuum in practice, so there will be some gas in the inner cavity of the shell 1 to a greater or lesser extent. In this embodiment, the first water collection pipe 11 and the second water collection pipe 7 are both in an inclined state. Then, when the rotor 2 rotates, the first water collection 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 collection 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 achieving cooling of the upper surface and lower surface of the rotor 2. In addition, the first water collection pipe 11 and the second water collection pipe 7 are both in an inclined state, which helps the migration of bubbles during cooling, and finally allows the bubbles to be discharged, greatly reducing the probability of gas plug formation and improving the cooling effect. In addition, in this embodiment, the squirrel cage structure can be pulled by the first water collection pipe 11 and the second water collection pipe 7 to ensure the strength, integrity and stability of the entire cooling structure. In this embodiment, since the first water channel 5 and the second water channel 6 are both arranged inside the rotating shaft 4, when the cooling water flows in the first water channel 5 and the second water channel 6, the rotating shaft 4 can be cooled. In addition, since the present invention can cool the rotating shaft 4, the heat in the rotor 2 (mainly the part of the center of the rotor 2 close to the rotating shaft 4) can be transferred to the rotating shaft 4 by heat transfer, so the present invention can also indirectly achieve 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.In addition, the lower water collecting ring 10, the upper water collecting ring 8 and the water cooling tube 9 of this embodiment form a squirrel cage structure as a whole, and the squirrel cage structure is located at the outer edge of the rotor 2 as a whole, so that the outer edge of the rotor 2 (especially the side wall of the rotor 2) can be cooled. From the above scheme of this embodiment, it can be seen that this embodiment can cool the central part, outer edge part, upper surface part and lower surface part of the rotor 2, and has the characteristic of good cooling effect.

[0020] The cooling method of the flywheel energy storage system in the above embodiment of the present invention includes the following process: Cooling water is introduced into the first water channel 5, and 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 tube 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 from top to bottom along the first water channel 5 in the rotating shaft 4. When it flows to the lower end of the first water channel 5, the cooling water flows to the lower water collecting ring 10 through the first water collecting pipe 11. The cooling water entering the lower water collecting ring 10 enters the lower ends of each water-cooling tube 9 after being distributed by the lower water collecting ring 10 and flows along the water-cooling tube 9 from bottom to top. Then the cooling water flows out from the upper end of the water-cooling tube 9 and 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 of the rotating shaft 4 and the rotor 2 is achieved. 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 collection pipe 11 is located upstream of the second water collection pipe 7, so the temperature of the cooling water in the first water collection pipe 11 is lower than the temperature of the cooling water in the second water collection pipe 7.

[0021] 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 of the rotating shaft 4 during rotation can be reduced.

[0022] As a preferred embodiment of the present invention, in this embodiment, the lower end of the first water channel 5 is connected to 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 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 circumference of the lower water collecting ring 10 and are connected to the lower water collecting ring 10. The purpose of such a setting is that all the first water collecting pipes 11 are evenly distributed in the circumference of the rotating shaft 4, and the rotation center of all the first water collecting pipes 11 as a whole is concentric with the rotating shaft 4, so that the vibration of the rotating shaft 4 when rotating can be reduced.

[0023] 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 opened in the circumference 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 circumference 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 circumference 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 of the rotating shaft 4 when it rotates.

[0024] As a preferred embodiment of the present invention, see Figure 3 In this embodiment, 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 the two adjacent water cooling pipes 9 and the lower water collecting ring 10. On the one hand, this structural design is to prevent the cooling water transported by the first water collecting pipe 11 from preferentially flowing away from the water cooling pipe 9 closer to the first water collecting pipe 11 in the lower water collecting ring 10, resulting in uneven water distribution in the lower water collecting ring 10, and then 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 higher temperature area on the rotor 2 will be greater than that of the lower temperature area, which will cause the shape of the rotor 2 to be asymmetric, and then the eccentricity between the center of mass of the rotor 2 and the center of the rotating shaft 4 will increase, and then the rotor 2 will 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 substantially the same speed, thus ensuring that the water temperature of the cooling water at both sides of each first water collecting pipe 11 is substantially symmetrical, which means that the density distribution of the cooling water is also substantially symmetrical in the squirrel cage structure. Since the eccentricity of the center of mass of the rotor 2 will cause the rotor 2 to generate a large vibration when rotating with the rotating shaft 4 when the rotor 2 rotates at a high speed, 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 the shape of the remaining water after all the pipes in the squirrel cage structure are removed is the same as the shape 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 type) due to the uneven density of the cooling water in the squirrel cage structure, which increases the eccentricity between the center of mass of the overall structure formed by the squirrel cage structure and the cooling water inside and the center of the rotating shaft 4, resulting in unstable rotation of the rotor 2 at high speed.

[0025] As a preferred embodiment of the present invention, see Figure 3In this embodiment, 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. The function and purpose of the structural design of this embodiment correspond to the function and purpose of the connection point between the first water collecting pipe 11 and the lower water collecting ring 10 located at the midpoint of the connection points between two adjacent water cooling pipes 9 and the lower water collecting ring 10 in the above embodiment, and will not be repeated here.

[0026] As a preferred embodiment of the present invention, in this embodiment, the second water collection pipe 7 and the first water collection pipe 11 are both straight pipes, the axis of the second water collection pipe 7 intersects with the axis of the rotating shaft 4, and the axis of the first water collection pipe 11 intersects with the axis of the rotating shaft 4. In this embodiment, the above-mentioned design of the second water collection pipe 7 and the first water collection pipe 11 makes the second water collection pipe 7 and the first water collection pipe 11 mainly subjected to tension or pressure during the rotation of the rotor 2, avoiding bending moment, thereby avoiding the second water collection pipe 7 and the first water collection pipe 11 from bending in the rotation plane of the second water collection pipe 7 and the first water collection pipe 11 when the rotor 2 rotates at high speed, thereby avoiding causing large additional stress to the connection points at both ends of the second water collection pipe 7 and the connection points at both ends of the first water collection pipe 11, resulting in reduced reliability at the connection points of the second water collection pipe 7 and the first water collection pipe 11. In addition, it is also to avoid the increase in the eccentricity between the center of mass of the overall structure composed of the second water collection pipe 7 and the first water collection pipe 11 and the cooling water inside them and the center of the rotating shaft 4, which leads to unstable rotation of the rotor 2 at high speed.

[0027] As an optional implementation scheme of the present invention, in this embodiment, the rotor 2 is cylindrical in shape, and correspondingly, 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.

[0028] As an optional implementation scheme of the present invention, in this embodiment, the surface shape of the upper water collecting ring 8, the lower water collecting ring 10 and the water cooling tube 9 in contact with the rotor 2 is set to a curved surface that matches the shape of the contact part of the rotor 2, so as to increase the contact area of ​​the upper water collecting ring 8, the lower water collecting ring 10 and the water cooling tube 9 in contact with the rotor 2, thereby improving the cooling effect on the rotor 2. For example, the side surface of the water cooling tube 9 facing the side wall of the rotor 2 can be set to a cylindrical surface with the same curvature as the curvature of the side wall of the rotor 2, so that the water cooling tube 9 forms a surface contact with the side wall of the rotor 2, thereby improving the heat exchange effect.

[0029] As an optional embodiment of the present invention, refer to Figure 1 In this embodiment, the flywheel energy storage system of the present invention further includes a motor 3, which is connected to the upper end of the rotating shaft 4 and is located outside the housing 1, wherein the motor 3 can be an electric motor or a generator.

[0030] Example See also Figure 3 The flywheel energy storage system of this embodiment includes a rotor assembly, a shell 1 and an electric motor. The rotor assembly includes a rotating shaft 4 and a rotor 2. The rotor 2 is coaxially mounted on the rotating shaft 4. The upper end of the rotating shaft 4 passes through the shell 1 and is sealed and rotatably connected to the shell 1. The lower end of the rotating shaft 4 is rotatably connected to the shell 1. The rotor 2 is in the shell 1. 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. Twelve water cooling tubes 9 are evenly provided on the outer wall surface of the rotor 2 along the circumference of the rotor 2. The upper ends of the water cooling tubes 9 are connected to the upper water collecting ring 8, and the lower ends of the water cooling tubes 9 are connected to 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 upper ends of the second water channel 6 extend to the upper end surface of the rotating shaft 4. The first water channel 5 is along the axis of the rotating shaft 4. The first water channel 5 is arranged in a central position, 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 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 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 and the lower water collecting ring 10 are symmetrically distributed in the circumferential direction of the lower water collecting ring 10, 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 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 and 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 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. 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 the two adjacent water cooling pipes 9 and the upper water collecting ring 8. Along the axial direction of the rotating shaft 4, the angle between the second water collecting pipe 7 and the first water collecting pipe 11 is 90°. 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. The shape of the rotor 2 is cylindrical, and the shapes of the upper water collecting ring 8 and the lower water collecting ring 10 are both circular. 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. The motor is connected to the upper end of the rotating shaft 4 and is located outside the housing 1. Correspondingly, in this embodiment, a first water channel interface 501 is set at the water inlet end of the first water channel 5, and a second water channel interface 601 is set 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, 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.

[0031] The cooling method of the flywheel energy storage system of this embodiment includes the following process: 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 sent to the lower water collecting ring 10 through the two first water collecting pipes 11. The cooling water in the lower water collecting ring 10 flows symmetrically on both sides of the two connecting points (i.e., the connecting points between the two first water collecting pipes 11 and the lower water collecting ring 10). Since the two connecting points (i.e., the connecting points between 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., about the axis of the two first water collecting pipes 11 and the rotation axis). The cooling water in the upper water collecting ring 8 is symmetrical (the plane where the axis of the shaft 4 is located is symmetrical), and then flows upward along the water cooling pipe 9 to 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 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 the two adjacent water cooling pipes 9 and the lower water collecting ring 10, and 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 the 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 (that is, the axes of the two first water collecting pipes 11 and the plane where the axis of the rotating shaft 4 is located are symmetrical). The cooling water in the upper water collecting ring 8 is then transported to the two second water channels 6 along the two second water collecting pipes 7, and discharged from the second water channels 6. Since the angle between the second water collecting pipe 7 and the first water collecting pipe 11 along the axial direction of the rotating shaft 4 is 90°, for the upper water collecting ring 8, the temperature of the cooling water is basically the same at the position connected to the two second water collecting pipes 7, 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 of the flywheel energy storage system during rotation, which is beneficial to the stable operation of the rotor assembly and the cooling structure at high speed.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection 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) and the upper water collecting ring (8) are connected through a second water collecting pipe (7).

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 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).

8. 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).

9. 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.

10. The cooling method of the flywheel energy storage system according to any one of claims 1 to 9, 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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