Flywheel energy storage shell and preparation method thereof

Abstract

The invention provides a flywheel energy storage shell and a preparation method thereof. The flywheel energy storage shell comprises a vacuum sealing layer, an energy absorption layer and a protective layer which are sequentially coated from inside to outside. The protective layer comprises a first outer layer with an arch structure, a first concrete layer filled in the arch structure, and a second concrete layer arranged between the first outer layer and the energy absorption layer. By adopting a three-layer protection system composed of the steel arch structure, the silicon carbide microsphere reinforced concrete layer and the titanium alloy solid layer, the safety performance is greatly improved, compared with a pure steel shell, the weight is reduced by 40%, the system energy density is improved by 15%, the titanium alloy consumption is reduced by 50%, and the total cost is reduced by about 35% due to the fact that the concrete layer replaces part of a composite material.

Description

Technical Field

[0001] This application relates to the field of flywheel energy storage housing design technology, and in particular to a flywheel energy storage housing and its preparation method. Background Technology

[0002] Flywheel energy storage, as a highly efficient physical energy storage technology, has shown broad application prospects in various fields such as power grid frequency regulation, data center uninterruptible power supplies, and rail transit energy recovery due to its advantages such as fast charging and discharging speed, long cycle life, and environmental friendliness. One of the core components of a flywheel energy storage device is the flywheel rotor, while the flywheel energy storage shell plays a crucial role in protecting and supporting the rotor and maintaining the internal vacuum environment. Its performance directly affects the safety, reliability, and energy efficiency of the flywheel energy storage device.

[0003] However, existing flywheel energy storage housings have many design and manufacturing defects, which limit the further development and widespread application of flywheel energy storage technology, as follows: 1. Single-layer steel structures require excessively thickened walls to ensure safety, resulting in heavy weight and low energy efficiency; 2. Composite material shells are expensive, and large-size vacuum seals are difficult to manufacture; 3. The impact resistance design is simple, and the ability to contain fragments is limited when the rotor breaks. Summary of the Invention

[0004] Based on this, the purpose of this application is to propose a flywheel energy storage shell and its preparation method, which aims to solve the problems of excessive weight, low energy efficiency and high manufacturing cost of traditional flywheel energy storage shells.

[0005] In a first aspect, this application proposes a flywheel energy storage housing, which includes: The layers are, from the inside out, a vacuum sealing layer, an energy absorption layer, and a protective layer. The protective layer includes a first outer layer with an arched structure, a first concrete layer filled in the arched structure, and a second concrete layer disposed between the first outer layer and the energy-absorbing layer.

[0006] In some embodiments, the energy absorption layer is a solid titanium alloy layer with a thickness of 5-10 mm.

[0007] In some embodiments, the vacuum sealing layer is a rubber layer, and a vacuum grease layer is provided between the rubber layer and the energy absorption layer, so that the rubber layer is bonded to the energy absorption layer through the vacuum grease layer.

[0008] In some embodiments, both the first concrete layer and the second concrete layer are doped with silicon carbide microspheres, the silicon carbide microspheres having a particle size of 50-100 μm and a volume percentage of 15%-30%.

[0009] In some embodiments, both the first concrete layer and the second concrete layer are doped with alumina hollow microspheres, the alumina hollow microspheres having a particle size of 0.5-1 mm and a volume percentage of 15%-30%.

[0010] In some embodiments, the first outer layer is a steel layer with a thickness of 20-40 mm.

[0011] In some embodiments, the radius of curvature of the arch structure is 1-2m.

[0012] In some embodiments, the rubber layer has a honeycomb-shaped absorption groove on the side facing the vacuum sealing layer.

[0013] Secondly, this application proposes a method for preparing a flywheel energy storage housing, used to prepare the flywheel energy storage housing according to any one of claims 1-7, the preparation method comprising: Prepare a vacuum sealing layer, an energy absorption layer, and a protective layer that are sequentially coated from the inside out; The protective layer includes a first outer layer with an arched structure, a first concrete layer filled in the arched structure, and a second concrete layer disposed between the first outer layer and the energy-absorbing layer.

[0014] In some embodiments, the vacuum sealing layer is a rubber layer, and a vacuum grease layer is coated on the side of the rubber layer facing the energy absorption layer.

[0015] Compared with the prior art, this application has the following advantages: 1. By employing a three-layer protection system consisting of a steel arch structure, a silicon carbide microsphere-reinforced concrete layer, and a solid titanium alloy layer, safety performance is significantly improved. The steel arch structure disperses impact force and avoids localized stress concentration; the silicon carbide microspheres in the concrete layer hinder fragment penetration and absorb impact energy; the solid titanium alloy layer efficiently absorbs energy through its own deformation and honeycomb structure. These three elements work synergistically to effectively contain fragments in the event of flywheel rotor fracture, preventing damage to surrounding equipment and personnel, and greatly enhancing the safety of the flywheel energy storage shell.

[0016] 2. Lightweight design is achieved through a multi-layered composite structure, with an estimated 40% weight reduction compared to a pure steel shell and a 15% increase in system energy density. The optimized steel arch structure reduces material usage, lightweight concrete incorporates alumina hollow microspheres to lower density, and the titanium alloy layer thickness is precisely controlled. This design fully utilizes material properties, reduces material redundancy, lowers rotational energy consumption, and allows more energy to be used for storage and release, thus improving energy storage efficiency.

[0017] 3. Costs are significantly reduced through optimization of materials and structure. The amount of titanium alloy used is reduced by 50%, and the replacement of some composite materials with concrete layers reduces the total cost by about 35%. Reducing the amount of expensive titanium alloy directly reduces costs, while concrete materials are inexpensive and have a simple preparation process.

[0018] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by means of embodiments thereof. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the structure of a flywheel energy storage shell according to the first embodiment of this application.

[0020] Symbol explanation: First outer layer - 101, First concrete layer - 102, Second concrete layer - 103, Energy absorption layer - 20, Vacuum sealing layer - 30.

[0021] The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation

[0022] The present application will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present application can be combined with each other.

[0023] The following detailed descriptions are exemplary and intended to provide further detailed explanation of this application. Unless otherwise specified, all technical terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application.

[0024] Example 1 like Figure 1 As shown, the first embodiment of the present invention proposes a flywheel energy storage shell, which includes a vacuum sealing layer 30, an energy absorption layer 20, and a protective layer, which are sequentially covered from the inside to the outside, wherein: The protective layer includes a first outer layer 101 with an arched structure, a first concrete layer 102 filled in the arched structure, and a second concrete layer 103 disposed between the first outer layer 101 and the energy absorption layer 20.

[0025] It should be noted that a vacuum sealing layer 30, an energy absorption layer 20, and a protective layer are sequentially arranged from the inside out, forming a multi-layered composite structure. This layered design can fully utilize the characteristics of each layer of materials, achieve the synergistic effect of multiple functions, comprehensively improve the overall performance of the flywheel energy storage shell, and provide more reliable and comprehensive protection for the flywheel energy storage system.

[0026] Furthermore, the vacuum sealing layer 30 effectively prevents external air from contacting the inside of the flywheel energy storage system, reducing energy loss caused by factors such as air friction, improving the energy conversion efficiency and storage efficiency of the flywheel energy storage system, enabling the system to retain stored energy for a longer period of time, and reducing unnecessary energy loss. The energy absorption layer 20 can absorb and disperse some energy when the flywheel energy storage system is subjected to external impact or vibration, reducing the direct impact force on the flywheel and other internal precision components, playing a buffering and shock absorption role, effectively protecting the safety and stability of the internal structure, and preventing equipment damage or performance degradation caused by external impact. The first outer layer 101 of the protective layer adopts an arched structure. The arched structure has good mechanical properties and can evenly distribute the external force to the surrounding structure, withstanding greater pressure and impact without easily deforming or being damaged. This design enhances the overall structural strength of the protective layer, improves the shell's ability to resist external mechanical damage, and provides a more robust external protective barrier for the flywheel energy storage system. The first concrete layer 102 further enhances the stability and integrity of the arched structure, enabling the protective layer to better withstand and disperse external forces. Meanwhile, concrete has a certain degree of toughness and impact resistance, which can effectively absorb and dissipate impact energy and reduce the degree of damage to the internal structure caused by external impact; the second concrete layer 103 plays a good transition and connection role, increases the bonding strength between the protective layer and the energy absorption layer 20, and makes the entire shell structure more compact and stable.

[0027] In some embodiments, the energy-absorbing layer 20 is a solid titanium alloy layer with a thickness of 5-10 mm. Titanium alloy itself has excellent toughness and strength, and this thickness can effectively absorb and disperse impact energy, protecting the internal structure; it can withstand the centrifugal force and mechanical stress of the high-speed rotation of the flywheel. Furthermore, if the thickness of the solid titanium alloy layer is too high, it will increase the weight of the outer casing, making transportation and installation more difficult, while also increasing material costs, with limited performance improvement; if the thickness of the solid titanium alloy layer is too low, energy absorption will be insufficient, making it difficult to effectively buffer impacts, and the mechanical strength will be insufficient, making it prone to fatigue cracks. For example, the thickness of the solid titanium alloy layer can be 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc.

[0028] In some embodiments, the vacuum sealing layer 30 is a rubber layer, and a vacuum grease layer is provided between the rubber layer and the energy absorption layer 20. The rubber layer adheres to the energy absorption layer 20 through the vacuum grease layer. The vacuum sealing layer 30 is constructed by the cooperation of the rubber layer and the vacuum grease layer. The rubber layer, with its flexibility and elasticity, adheres tightly to the energy absorption layer 20 to initially seal the gap, while the vacuum grease layer, with its excellent sealing and adhesion, further fills the microscopic unevenness and enhances the bond. The two form a double seal, effectively preventing the infiltration of external air, greatly reducing the frictional resistance between the flywheel and the air during rotation, improving energy conversion and energy storage efficiency, while isolating oxygen and contaminants, preventing oxidation and corrosion of internal metal components, avoiding damage from contaminants, ensuring stable system operation, and extending the service life of the equipment.

[0029] In some embodiments, both the first concrete layer 102 and the second concrete layer 103 are doped with silicon carbide microspheres. The particle size of the silicon carbide microspheres is 50-100 μm, and the volume fraction of the silicon carbide microspheres is 15%-30%. The high hardness of the silicon carbide microspheres can significantly enhance the compressive strength and wear resistance of the concrete layer, making it better resistant to external mechanical impact and wear. Its good thermal stability helps maintain the structural stability of the concrete layer under different temperature environments, reducing problems such as cracking caused by thermal expansion and contraction. At the same time, a suitable particle size and volume fraction can optimize the internal structure of the concrete, improve its density, enhance the synergistic effect of energy absorption and protection, and thus comprehensively improve the protective performance and reliability of the flywheel energy storage shell. If the particle size of the silicon carbide microspheres is too high, it is difficult to disperse evenly during concrete mixing, and it is easy to locally aggregate, making the internal structure of the concrete layer uneven and reducing the overall strength and impact resistance. If the particle size is too low, the preparation cost increases, and small-sized microspheres are prone to agglomeration. It will also form a weak interface layer due to the small spacing, reducing the reinforcement effect and increasing the viscosity of the concrete. For example, the particle size of silicon carbide microspheres can be 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, etc. When the volume fraction of silicon carbide microspheres is too high, it increases the rigidity of the concrete layer and reduces its toughness, making it prone to brittle fracture upon impact. If the volume fraction is too low, the reinforcing effect of the silicon carbide microspheres cannot be fully utilized, resulting in minimal improvement in the performance of the concrete layer and limited improvement to the internal structure. For example, the volume fraction of silicon carbide microspheres can be 15%, 20%, 25%, 30%, etc.

[0030] Furthermore, in some embodiments, both the first concrete layer 102 and the second concrete layer 103 are doped with alumina hollow microspheres, the particle size of which is 0.5-1 mm, and the volume percentage of which is silicon carbide microspheres is 15%-30%. For example, the particle size of the alumina hollow microspheres can be 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, etc.; and the volume percentage of the silicon carbide microspheres can be 15%, 20%, 25%, 30%, etc.

[0031] Furthermore, in some embodiments, the first outer layer 101 is a steel layer with a thickness of 20-40 mm. An excessively thick steel layer can hinder heat dissipation within the system, affecting component performance and lifespan. Simultaneously, uneven stress distribution at connections with other components can easily lead to stress concentration, increasing the risk of fatigue cracks. Conversely, an excessively thin steel layer will result in insufficient strength, making it difficult to effectively resist external mechanical impacts. For example, the thickness of the steel layer can be 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, etc.

[0032] In some embodiments, the radius of curvature of the arch structure is 1-2m. For example, the radius of curvature can be 1mm, 1.5mm, 2mm, etc.

[0033] In some embodiments, the rubber layer is provided with honeycomb absorption grooves on the side facing the vacuum sealing layer 30, thereby further improving the energy absorption effect.

[0034] In summary, the flywheel energy storage casing described above has the following advantages: 1. By employing a three-layer protection system consisting of a steel arch structure, a silicon carbide microsphere-reinforced concrete layer, and a solid titanium alloy layer, safety performance is significantly improved. The steel arch structure disperses impact force and avoids localized stress concentration; the silicon carbide microspheres in the concrete layer hinder fragment penetration and absorb impact energy; the solid titanium alloy layer efficiently absorbs energy through its own deformation and honeycomb structure. These three elements work synergistically to effectively contain fragments in the event of flywheel rotor fracture, preventing damage to surrounding equipment and personnel, and greatly enhancing the safety of the flywheel energy storage shell.

[0035] 2. Lightweight design is achieved through a multi-layered composite structure, with an estimated 40% weight reduction compared to a pure steel shell and a 15% increase in system energy density. The optimized steel arch structure reduces material usage, lightweight concrete incorporates alumina hollow microspheres to lower density, and the titanium alloy layer thickness is precisely controlled. This design fully utilizes material properties, reduces material redundancy, lowers rotational energy consumption, and allows more energy to be used for storage and release, thus improving energy storage efficiency.

[0036] 3. Costs are significantly reduced through optimization of materials and structure, with a 50% reduction in titanium alloy usage and the replacement of some composite materials with concrete layers, thus lowering the overall cost.

[0037] Example 2 (1) Preparation of the first outer layer in the protective layer: Select 30mm thick Q390D high-strength steel plates and perform steel plate pretreatment. First, use sandblasting to remove rust and impurities from the steel plate surface. Laser cutting equipment is used to cut steel plates into blanks; An 800T hydraulic press is used to cold press the cut steel plate to form an arched structure with a radius of curvature R = 1.2m; The formed arched steel plate is subjected to residual stress relief heat treatment at a temperature of 600℃ for 2 hours.

[0038] (2) Preparation of concrete layer in protective layer: Preparation of the first concrete layer: Prepare lightweight concrete with a density of 1.8 g / L. Alumina hollow microspheres with a particle size of 0.8 mm and a volume ratio of 30% are added to concrete, and the mixture is stirred evenly. The pouring is carried out in layers. First, the formwork is supported, and then the pouring is done in three layers, with each layer 24 hours apart. After the pouring is completed, steam curing is carried out at a temperature of 60℃ for 72 hours. After curing, the surface of the concrete layer is sealed.

[0039] (3) Preparation of the second concrete layer: its materials and preparation process are the same as those of the first concrete layer.

[0040] (4) Preparation of energy absorption layer: Select 8mm thick titanium-steel composite plate (TA2 / 20 steel), cut and form it, cut it with plasma cutting equipment, then roll the cut plate into a circle with a plate rolling machine, and then weld it by automatic submerged arc welding of longitudinal seam. After welding, X-ray flaw detection is performed to ensure that the interface bonding strength is ≥300MPa.

[0041] (5) Vacuum sealing layer installation: Select fluororubber O-rings (GB / T3452.2 standard), and pre-tighten the housing bolts before installation; Apply vacuum grease (perfluoropolyether type) evenly to the surface of the fluororubber O-ring; Install the fluororubber O-rings coated with vacuum grease into the designated positions according to the installation sequence, ensuring they adhere to the energy absorption layer.

[0042] The prepared protective layer, energy absorption layer, and components with the vacuum sealing layer installed are assembled as a whole, and then the vacuuming operation is carried out in stages, using 10 -1 →10 -3 Using a step-down pressure reduction method, the vacuum level inside the casing is maintained at ≤1×10⁻⁶. - 3 Pa.

[0043] Example 3 This embodiment is basically the same as Embodiment 2, except that the doped alumina hollow microspheres are changed to silicon carbide microspheres with a particle size of 75 μm and the volume ratio remains unchanged.

[0044] Comparative Example 1 A flywheel energy storage shell with the exact same shape and size as in Example 2 or Example 3 was made of pure steel.

[0045] Comparative Example 2 A flywheel energy storage shell, identical in shape and size to that of Example 2 or Example 3, was made of titanium alloy. Results: Compared with Comparative Example 1, the flywheel energy storage shell prepared in Example 2 has the following advantages: the pure steel shell is 40% lighter, the system energy density is 15% higher, and the total cost is reduced by about 29%; Compared with Comparative Example 2, the flywheel energy storage shell prepared in Example 2 has the following advantages: the amount of titanium alloy used is reduced by 50%, the system energy density is increased by 12%, and the total cost is reduced by about 35%.

[0046] Compared with Comparative Example 1, the flywheel energy storage shell prepared in Example 3 has the following advantages: the pure steel shell reduces weight by 38%, the system energy density increases by 18%, and the total cost is reduced by about 26%. Compared with Comparative Example 2, the flywheel energy storage shell prepared in Example 3 has the following advantages: the amount of titanium alloy used is reduced by 46%, the system energy density increases by 13%, and the total cost is reduced by about 32%.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and not to limit them. Although this application has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of this application. Any modifications or equivalent substitutions that do not depart from the spirit and scope of this application should be covered within the protection scope of the claims of this application.

Claims

1. A flywheel energy storage enclosure, characterized by, It comprises: vacuum sealing layer, energy absorption layer, protective layer are sequentially coated from inside to outside; The protective layer comprises a first outer layer with an arch structure, a first concrete layer filled in the arch structure, and a second concrete layer arranged between the first outer layer and the energy absorption layer.

2. The flywheel energy storage enclosure of claim 1, wherein, The energy absorption layer is a titanium alloy solid layer, and the thickness of the titanium alloy solid layer is 5-10mm.

3. The flywheel energy storage enclosure of claim 1, wherein, The vacuum sealing layer is a rubber layer, and a vacuum grease layer is arranged between the rubber layer and the energy absorption layer, and the rubber layer is attached to the energy absorption layer through the vacuum grease layer.

4. The flywheel energy storage enclosure of claim 1, wherein, The first concrete layer and the second concrete layer are both doped with silicon carbide microspheres, the particle size of the silicon carbide microspheres is 50-100μm, and the volume fraction of the silicon carbide microspheres is 15%-30%.

5. The flywheel energy storage enclosure of claim 1, wherein, The first concrete layer and the second concrete layer are both doped with aluminum oxide hollow microspheres, the particle size of the aluminum oxide hollow microspheres is 0.5-1mm, and the volume fraction of the aluminum oxide hollow microspheres is 15%-30%.

6. The flywheel energy storage enclosure of claim 1, wherein, The first outer layer is a steel layer, and the thickness of the steel layer is 20-40mm.

7. The flywheel energy storage enclosure of claim 1, wherein, The curvature radius of the arch structure is 1-2m.

8. The flywheel energy storage enclosure of claim 3, wherein, The side of the rubber layer facing the vacuum sealing layer is provided with a honeycomb-shaped absorption groove.

9. A method of manufacturing a flywheel energy storage enclosure, for manufacturing a flywheel energy storage enclosure according to any one of claims 1 to 7, characterised in that, The preparation method comprises: Preparation of vacuum sealing layer, energy absorption layer, protective layer are sequentially coated from inside to outside; The protective layer comprises a first outer layer with an arch structure, a first concrete layer filled in the arch structure, and a second concrete layer arranged between the first outer layer and the energy absorption layer.

10. The method of claim 8, wherein the flywheel energy storage enclosure is prepared by, The prepared vacuum sealing layer is a rubber layer, and a vacuum grease layer is coated on one side of the rubber layer facing the energy absorption layer.

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