Flywheel power storage device

Abstract

To provide a flywheel power storage device capable of not only being miniaturized but also drastically improving maximum device mass energy density.SOLUTION: A flywheel power storage device comprises a power generator motor unit 3 and a flywheel unit 2. The flywheel unit 2 includes: support shafts 5A and 5B; a pair of flywheel hubs 8A and 8B supported by the support shafts 5A and 5B; and rotary mass rings 9A and 9B provided on outer peripheries of the flywheel hubs 8A and 8B, respectively. The generator motor unit 3 includes a stator unit 10 by an iron non-core excitation induction coil 11i that is provided between the flywheel hubs 8A and 8B, and rotor units 12A and 12B by a Halbach arrangement permanent magnet array held by the respective flywheel hubs. A housing is provided that supports the support shafts 5A and 5B and houses both the power generator motor unit 3 and the flywheel unit 2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a technique for improving the mass energy density of a flywheel electric power storage device. [Background technology]

[0002] A flywheel power storage device is a device that has the function of storing electric power in a flywheel and, conversely, receiving electric power from a flywheel via a means for converting electric energy into rotational kinetic energy and vice versa.

[0003] Compared to commonly used electrochemical storage devices (so-called secondary batteries), flywheel storage devices have excellent features such as stable functioning in both low-temperature and high-temperature environments, almost no deterioration in characteristics or lifespan even with repeated charging and discharging, and low internal resistance.

[0004] The use of this new energy storage device will enable improvements in environmental resistance, energy conservation, and ease of maintenance of conventional electrical equipment and systems that use secondary batteries. For these reasons, there is a strong desire for the further spread of flywheel energy storage devices and an expansion of their application areas.

[0005] The key issues for the widespread use of flywheel energy storage devices are to make them smaller and lighter in order to enhance their product appeal. Lightweighting can be rephrased as "improving the maximum device mass energy density" using the device's maximum mass energy density (the value obtained by dividing the maximum stored energy of the flywheel by the device's mass).

[0006] A flywheel energy storage device has two basic components: the flywheel, which stores energy as rotational motion, and the generator-motor, which converts between electric energy (electrical energy) and rotational motion energy upon command.

[0007] Of the above-mentioned most important issues, efforts to miniaturize the device are currently leading the way. Although there are some minor differences, all efforts share the common goal of integrating (or integrating) the flywheel and generator motor.

[0008] To explain it more specifically, this method involves sharing the rotating shaft of the flywheel unit and the rotating shaft of the generator motor unit, and arranging the flywheel unit and the generator motor unit concentrically on a single vertical plane of the rotating shaft.

[0009] A known example of an integrated flywheel power storage device is described in Patent Document 1. The flywheel power storage device described in Patent Document 1 includes an outer rotor type generator motor unit and a flywheel unit.

[0010] The generator motor and the flywheel share a rotating shaft, and the flywheel is disposed outside the generator motor so as to surround its outer periphery. Furthermore, by providing the main body of the flywheel on the rotor of the generator motor, integration is further enhanced. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Patent No. 4160022 Summary of the Invention [Problem to be solved by the invention]

[0012] However, in the conventional integrated flywheel energy storage device, although it is possible to achieve miniaturization of the device as described above, there is little hope of improving the maximum device mass energy density, which is the maximum mass energy density of the flywheel energy storage device.

[0013] In view of the above, an object of the present invention is to provide a flywheel electric storage device that can not only be made smaller, but also can dramatically improve the maximum device mass energy density. [Means for solving the problem]

[0014] In order to achieve this object, the present invention provides a flywheel power storage device comprising a generator motor section that converts electrical energy into rotational kinetic energy and vice versa, and a flywheel section that stores energy as rotational motion, the device comprising a housing that houses both the generator motor section and the flywheel section, the flywheel section comprising a support shaft whose central axis coincides with the rotational axis of the flywheel section, a pair of flywheel hubs supported coaxially on the support shaft, and annular rotating mass rings provided on the outer periphery of each flywheel hub, the generator motor section comprising a stator section formed by an ironless excitation induction coil provided between the pair of flywheel hubs, and a rotor section formed by a yokeless Halbach arrangement permanent magnet array held by each flywheel hub facing the ironless excitation induction coil of the stator section, and a housing that supports the support shaft and houses both the generator motor section and the flywheel section.

[0015] In the present invention, it is preferable that at least one or all of the flywheel hub, the support shaft, and the housing are made of light metal or carbon fiber reinforced plastic.

[0016] Furthermore, the present invention is characterized in that an annular space is formed between the rotating mass circle of the flywheel section and the support shaft, and a bidirectional inverter section for supplying power to and receiving power from the generator motor section is housed in the annular space.

[0017] The present invention is also characterized in that an exhaust device is provided inside the housing for exhausting air to evacuate at least the rotational regions of the generator motor section and the flywheel section inside the housing.

[0018] The present invention is characterized in that it includes a first power storage unit constituted by the generator motor unit and the flywheel unit, and a second power storage unit constituted by the generator motor unit and the flywheel unit that rotates in a reverse direction at a constant speed relative to the first power storage unit, and the first power storage units and the second power storage units are arranged in equal numbers on the same rotation axis.

[0019] The flywheel portion of a flywheel energy storage device generally consists of three main elements. The first element is a rotating mass ring (including cylindrical rings) that rotates circumferentially and stores rotational kinetic energy. The second element is a support shaft, which is the flywheel's central shaft that defines the center of rotation of the rotating rotating mass ring. The third element is a flywheel hub that supports the rotating mass ring and keeps it equidistant from the flywheel's central shaft. Here, the flywheel hub and rotating mass ring rotate together. The support shaft is supported by a housing. One configuration is possible: the support shaft is fixedly held by the housing and rotatably supports the flywheel hub; the other is the support shaft is rotatably supported by the housing and rotates together with the flywheel hub. Either of these configurations can be selectively adopted.

[0020] On the other hand, the basic components of the generator motor (using the widely used example of a permanent magnet three-phase synchronous generator motor) generally consist of two components: a stator with a fixed excitation induction coil, and a freely rotatable rotor with permanent magnets that generate a strong static magnetic field, either installed on the surface or embedded in the rotor. The stator and rotor are arranged to share a central axis, and the excitation induction coil of the stator and the permanent magnet of the rotor face each other across a narrow gap.

[0021] The flywheel energy storage device of the present invention is based on the principle of maximizing the mass energy density of the rotating mass ring of the flywheel portion without reducing it, and is realized by rationally reducing the number of iron parts, which are elements that generate high loads.

[0022] Therefore, according to the present invention, it is possible to provide a flywheel electric storage device that can not only be made smaller, but also can dramatically improve the maximum device mass energy density. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is an explanatory cross-sectional view showing the configuration of a flywheel electricity storage device according to a first embodiment of the present invention. [Figure 2] FIG. 6 is an explanatory cross-sectional view showing the configuration of a flywheel electricity storage device according to a second embodiment of the present invention. [Figure 3] FIG. 10 is an explanatory cross-sectional view showing the configuration of a flywheel electricity storage device according to a third embodiment of the present invention. [Figure 4] FIG. 10 is an explanatory cross-sectional view showing the configuration of a flywheel electricity storage device according to a fourth embodiment of the present invention. [Figure 5] FIG. 10 is an explanatory cross-sectional view showing the configuration of a flywheel electricity storage device according to a fifth embodiment of the present invention. [Figure 6] FIG. 10 is an explanatory cross-sectional view showing the configuration of a flywheel electricity storage device according to a sixth embodiment of the present invention. [Figure 7] FIG. 11 is an explanatory cross-sectional view showing the configuration of a flywheel electricity storage device according to a seventh embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] The flywheel energy storage device according to each embodiment of the present invention is based on the principle of maximizing the circular energy density of the rotating mass circular ring of the flywheel portion without reducing it, and is realized by rationally reducing the iron parts that generate high loads.

[0025] The total mass of the flywheel storage device (the sum of the mass of the flywheel and the mass of the generator motor) is M sys The maximum rotational kinetic energy stored in the rotating mass circle of the flywheel section is E fw Then, the maximum device mass energy density of the flywheel energy storage device is D sys is defined by the following equation (1):

[0026] D sys = E fw / M sys ···(1)

[0027] On the other hand, the maximum mass energy density of the rotating mass ring D fw is widely used. The mass of the rotating mass ring is m fw This gives the following equation (2).

[0028] D fw = E fw / m fw ···(2)

[0029] D fw To understand the relationship between the mass density (or specific gravity) of the rotating mass ring and the material of the rotating mass ring, let ρ and σ be the mass density (or specific gravity) of the rotating mass ring and the yield strength of the rotating mass ring, respectively. y As a result, E in the above equation fw and m fw By formulating and calculating the above, the following equation (3) is finally derived.

[0030] D fw = K(σ y / ρ)···(3)

[0031] Here, K is a coefficient that increases gradually and monotonically from 0.3 to 0.5 depending on the ratio of the inner radius to the outer radius of the rotating mass ring, and is sometimes called the shape factor.

[0032] Combining the above equations (1) and (2), we get the following D sys and D fw The following relation (4) is obtained.

[0033] D sys = (m fw / M sys )D fw =(m fw / (m fw +M oth ))D fw ···(4)

[0034] M in the above equation (4) othis the mass of the flywheel storage device M sys Mass of the rotating mass ring m fw This is the total mass excluding the rotating mass ring.

[0035] The inventors focused on the middle part of the above analytical equation (4) and calculated the maximum device mass energy density D sys To improve this, the mass ratio m of the rotating mass disc and the flywheel storage device fw / M sys and the energy density of the rotating mass ring D fw It has been found that this can be achieved by increasing the product of

[0036] Furthermore, looking at the right side of equation (4), the maximum device mass energy density D sys To improve the energy density, two design steps become clear: First, the annular mass energy density D fw Rotating mass circular material (σ y In the second step, the material with the highest ρ / ρ ratio is selected, and the M oth Maximize reduction of

[0037] Based on this, in the present invention, the maximum D fw To obtain this, a rotating mass ring made of high strength carbon fiber reinforced plastic (hereinafter referred to as CFRP) is used, and the mass M oth To reduce this, an axial flux permanent magnet (AFPM) generator motor is placed in the inner diameter space of the ring, oth Improvements are being implemented to remove bulk steel materials that make up a large portion of the vehicle's overall weight (such as the flywheel hub, motor yoke, and coil core) or to replace them with lightweight materials.

[0038] Hereinafter, embodiments of the present invention and their modifications will be described with reference to the drawings. However, in these drawings, the relationship between thickness and planar dimensions, the thickness ratio of each layer, etc. are exaggerated to facilitate understanding. Furthermore, the same components are given the same reference numerals and will not be described again.

[0039] [First embodiment] In the flywheel power storage device 1 according to the first embodiment, as shown in FIG. 1, a flywheel section 2 and a generator motor section 3 are integrated to rotate. center It rotates together with upper and lower rotating shafts 5A and 5B, which are a common support shaft installed on axis 4 (Z axis of the polar coordinate system), and stores and discharges electricity.

[0040] Reference numeral 5C denotes a coupling shaft that connects the upper and lower rotary shafts 5A and 5B. Reference numeral 6 denotes a central rotation plane (r-θ plane of the polar coordinate system) that is perpendicular to the central axis of rotation 4.

[0041] Upper and lower rotating shafts 5A, 5B and coupling shaft 5C The material is a light metal with high yield strength, such as extra super duralumin (A7075P) or 6Al-4V titanium alloy, and more preferably 6Al-6V-2Sn titanium alloy or 11.5Al-1Mo-6Zr-4.5Sn titanium alloy.

[0042] The flywheel section 2 is Central surface of revolution The upper flywheel 2A and the lower flywheel 2B are arranged parallel to each other with a central gap 7 provided in the rotor 6 therebetween, and the structure is vertically symmetrical.

[0043] Reference numeral 8A denotes a flywheel hub of the upper flywheel 2A, which is cylindrical and has a bottom plate. The flywheel hub 8A is fixed to the upper rotating shaft 5A or is mechanically firmly connected thereto.

[0044] Similarly, 8B is the flywheel hub of the lower flywheel 2B, which is cylindrical with a bottom plate (on top). The flywheel hub 8B is underThe rotor 5 is fixed to the rotary shaft 5B or is mechanically firmly connected thereto.

[0045] The flywheel hubs 8A and 8B are made of a light metal having high yield strength or CFRP (carbon fiber reinforced plastic).

[0046] In the case of light metals, for example, it is preferable to use extra super duralumin (A7075P) or 6Al-4V titanium alloy, and it is even more preferable to use 6Al-6V-2Sn titanium alloy or 11.5Al-1Mo-6Zr-4.5Sn titanium alloy.

[0047] In the case of CFRP, it is desirable to use a reinforced plastic in which carbon fibers with a tensile strength of 5 GPa or more are solidified at a filling rate of 0.6 or more.

[0048] Cylindrical upper and lower rotating mass rings 9A and 9B are circumscribed on the outer edges of the flywheel hubs 8A and 8B, respectively.

[0049] The rotating mass rings 9A and 9B are made of CFRP with a tensile strength of 6 GPa or more, reinforced by winding carbon fibers in the circumferential direction, with a filling rate of 60% to 70%. Such CFRP can be formed using the well-known filament winding method or sheet winding method.

[0050] As mentioned above, an AFPM type generator motor is used in the generator motor section 3. In Fig. 1, 10 is a stator section of the generator motor section 3, which is in the form of a hollow disk having a circular hole with an inner diameter larger than the outer diameter of the coupling shaft 5C.

[0051] The stator section 10 is disposed at the position of the central gap 7, with a small gap between the upper flywheel 2A and the lower flywheel 2B. Inside the stator section 10, near the rotating shafts 5A and 5B and at a predetermined distance from the central axis of rotation 4, a plurality of coreless exciting induction coils 11i (i = 1, 2, ..., n) are arranged and fixed at equal angular intervals in the circumferential direction, with their magnetic flux intersection planes facing in the Z-axis direction.

[0052] The material of the stator section 10, except for the coreless excitation induction coil 11i made of copper wire, is selected from light metal or CFRP (carbon fiber reinforced plastic) having high yield strength, or a composite material of both materials.

[0053] In the case of light metals, for example, it is preferable to use extra super duralumin (A7075P) or 6Al-4V titanium alloy, and it is even more preferable to use 6Al-6V-2Sn titanium alloy or 11.5Al-1Mo-6Zr-4.5Sn titanium alloy.

[0054] In the case of CFRP, it is desirable to use a reinforced plastic in which carbon fibers with a tensile strength of 5 GPa or more are solidified at a filling rate of 0.6 or more.

[0055] In order to further reduce the weight of the stator portion 10, the portion corresponding to the coreless excitation induction coil 11i and the upper and lower portions described later are support The rest of the structure, excluding the connecting sections of the defensive wall, will be hollowed out and designed as a beam structure, as far as structural strength constraints allow.

[0056] The AFPM generator motor section 3 comprises a pair of upper and lower rotor sections 12A and 12B as shown in the figure. The rotor sections 12A and 12B are integrally formed with the bottom plates of the upper and lower flywheel hubs 8A and 8B.

[0057] Rotor elements 13Ai (i = 1, 2, . . . , k) and 13Bi (i = 1, 2, . . . , k) are annular permanent magnet arrays (where k ≠ n) in a yokeless Halbach configuration, attached so that the side where the magnetic field is stronger faces the coreless exciting induction coil 11i (i = 1, 2, . . . , n). The annular permanent magnet arrays 13Ai and 13Bi are fitted and fixed in annular recesses (with a depth equal to or less than the thickness of the permanent magnets) carved into the bottom plates of the upper flywheel hub 8A and the lower flywheel hub 8B, respectively. The magnets are arranged so that the north magnetic pole of 13Ai always faces the north magnetic pole of 13Bi, and the north magnetic pole of 13Bi always faces the north magnetic pole of 13Bi.

[0058] The generator motor section 3 is configured to use a Halbach-arranged permanent magnet array that allows for magnetic connection (circuit) between adjacent permanent magnets. This eliminates the restriction of using heavy magnetic materials and yokes for the base material of the rotor sections 12A and 12B, making it possible to use light materials such as light metals and CFRP, and also makes it possible to configure the rotor sections 12A and 12B and the flywheel hubs 8A and 8B from the same base material.

[0059] Next, a description will be given of parts relating to the casing frame of the flywheel energy storage device 1 according to the first embodiment of the present invention.

[0060] Reference numerals 14A and 14B denote the circular upper and lower support plates, respectively, of the flywheel energy storage device 1. The upper support plate 14A supports the upper rotating shaft 5A via a bearing portion 15A consisting of a pair of a radial bearing and a thrust bearing. Similarly, the lower support plate 14B supports the upper rotating shaft 5A via a similar bearing portion 15B. under Rotating shaft 5 B The bearing can be selected from various known bearings, such as ball bearings, sliding bearings, air bearings, and magnetic bearings.

[0061] The cylindrical upper and lower support defense walls 16A and 16B determine the relative positions of the support plates 14A, 14B, and the stator unit 10 and support the three. In the unlikely event that the flywheel unit 2, which is rotating at high speed, is broken, these support defense walls 16A and 16B also serve to prevent fragments from flying out.

[0062] The materials for the support plates 14A, 14B and the support defense walls 16A, 16B are selected from light metals with high yield strength. For example, ultra-super duralumin (A7075P) or a 6Al-4V titanium alloy is preferred, and a 6Al-6V-2Sn titanium alloy or an 11.5Al-1Mo-6Zr-4.5Sn titanium alloy is even more preferred. This allows for the weight reduction of the support plates 14A, 14B and the support defense walls 16A, 16B. The support plates 14A, 14B and the support defense walls 16A, 16B constitute the housing of the present invention.

[0063] Generally, in a ring with a large ratio of inner radius to outer radius (ratio > 0.6), the rotational stress generated in the circumferential direction is much higher than the rotational stress generated in the radial direction. Rotating mass rings 9A and 9B of the flywheel energy storage device 1 fall into this category.

[0064] In the first embodiment, the rotating mass rings 9A and 9B are made of CFRP (filling ratio 60% to 70%) reinforced by winding carbon fiber with a tensile strength of 6 GPa or more in the θ direction. This gives the rotating mass rings 9A and 9B a very high yield strength in the circumferential direction. In recent years, carbon fiber with a tensile strength of 6.4 GPa or more has become commercially available. When this is used with epoxy resin to produce a fiber filling ratio of 0.6, the mass density is 1.6 g / cm3 and the yield strength σ y =3.8GPa CFRP is obtained.

[0065] Here, the σ of the CFRP and nickel-chromium-molybdenum steel SNCM439, which is known as a high-strength industrial material, y / ρ value and σ y Maximum circular mass energy density D proportional to / ρ value fw When comparing the relative values, the CFRP used in the first embodiment has a D fw It was found that (σ y / ρ and D fw (See equation (2) above for the relationship.)

[0066] Also, other industrial materials and D fw This confirms that the first step in the design process described above has been highly fulfilled.

[0067] Next, the achievement level of this embodiment will be compared with that of the prior art in the second step of the design process described above.

[0068] Conventional flywheel energy storage devices have evolved by prioritizing downsizing while following the material structure of the previous generation flywheel energy storage devices, so the amount of iron used in the bulk parts is large, resulting in a large Moth, which is a factor in lowering the maximum device mass energy density Dsys. Bulk parts that contain a lot of iron include the rotating shaft, flywheel, Ha These include the rotor, excitation induction coil core, yokes for the rotor and stator parts, and the housing frame. It is presumed that the reason the iron materials remained is because they were essential elements for establishing the magnetic circuit of the generator motor (removing them would have meant that the integrated structure would not have been possible).

[0069] In contrast, as described above, the flywheel energy storage device 1 in the first embodiment employs the AFPM generator motor unit 3 having rotor sections 12A and 12B of a pair of Halbach-arranged permanent magnet arrays, and is configured such that the rotor sections 12A and 12B of the AFPM generator motor unit 3 are integrated with the flywheel hubs 8A and 8B, so that the iron material of these bulk parts can be eliminated (removed or replaced with a lightweight material).

[0070] Therefore, M oth The reduction in the mass energy density of the device has been remarkable, and the size has been reduced. sys (corresponding to weight reduction) improvement is achieved at the same time.

[0071] [Second embodiment] In the first embodiment, a configuration is adopted in which central shafts 5A, 5B, and 5C constituting the support shafts rotate integrally with rotating mass circles 9A and 9B and flywheel hubs 8A and 8B. A flywheel energy storage device 20 of a second embodiment, which will be described next, employs a configuration in which the central shafts constituting the support shafts are stationary (fixed).

[0072] 2 shows a cross section of a flywheel energy storage device 20 according to the second embodiment taken along a rotational axis 4 (Z-axis of a polar coordinate system). The same members as those in the first embodiment are denoted by the same reference numerals and will not be described.

[0073] In Figure 2, 21A is an upper stationary shaft and 21B is a lower stationary shaft. Both stationary shafts 21A, 21B are hollow (tubular) shafts. Their central axes coincide with the central axis of rotation 4. In the second embodiment, the flywheel unit 2 and the generator motor unit 3 are integrated and rotate around the central axis of rotation 4 (the Z-axis of the polar coordinate system) to store and discharge electricity, similar to the first embodiment. However, the difference is that both stationary shafts 21A, 21B do not rotate but remain stationary throughout.

[0074] The stationary shafts 21A and 21B are made of a light metal with high yield strength, such as extra super duralumin (A7075P) or an alloy such as 6Al-4V titanium, and more preferably, a 6Al-6V-2Sn titanium alloy or a 11.5Al-1Mo-6Zr-4.5Sn titanium alloy.

[0075] Reference numeral 22A denotes a flywheel hub belonging to the upper flywheel 2A, which is cylindrical with a hollow disk bottom plate. The flywheel hub 22A is connected to the upper stationary shaft 21A via a radial bearing of the upper bearing portion 23A and to the stator portion 24 (described later) via a thrust bearing.

[0076] Similarly, reference numeral 22B denotes a flywheel hub belonging to the lower flywheel 2B, which is cylindrical with a hollow disk-shaped bottom plate. The flywheel hub 22B is connected to the lower stationary shaft 21B via a radial bearing of the lower bearing portion 23B and to the stator portion 24 (described later) via a thrust bearing.

[0077] The bearings of the bearing portions 23A and 23B can be arbitrarily selected from various known bearings, such as ball bearings, sliding bearings, air bearings, and magnetic bearings.

[0078] Reference numeral 22C denotes a flywheel hub spacer that determines the width of the center gap 7, and after installation, is firmly connected to the upper flywheel hub 22A and the lower flywheel hub 22B.

[0079] The flywheel hubs 22A and 22B are made of a light metal with high yield strength, such as extra super duralumin (A7075P) or a 6Al-4V titanium alloy, or more preferably a 6Al-6V-2Sn titanium alloy or a 11.5Al-1Mo-6Zr-4.5Sn titanium alloy.

[0080] Cylindrical upper and lower rotating mass rings 9A and 9B are circumscribed on the outer edges of the flywheel hubs 22A and 22B, respectively.

[0081] Reference numeral 24 denotes a stator portion of the generator motor portion 3, which is firmly connected to the stationary shafts 21A and 21B. The stator portion 24 is disposed at the position of the central gap 7, and is separated from the upper flywheel 2A and the lower flywheel 2B by a small gap. The center of the stator portion 24 may be hollow or solid.

[0082] A light metal with high yield strength is selected as the material for the stator portion 24, except for the coreless excitation induction coil 11i made of copper wire. For example, extra super duralumin (A7075P) or a 6Al-4V titanium alloy is preferably used, and a 6Al-6V-2Sn titanium alloy or a 11.5Al-1Mo-6Zr-4.5Sn titanium alloy is even more preferable.

[0083] In order to further reduce the weight of the stator portion 24, it is desirable to hollow out the portion other than the portion corresponding to the coreless excitation induction coil 11i and the connection portion of the stationary shafts 21A and 21B as far as the structural strength allows, and design it as a beam structure.

[0084] The AFPM generator motor unit 3 has a pair of upper and lower rotor units 25A and 25B. The rotor units 25A and 25B are integrally formed with the bottom plates of the flywheel hubs 22A and 22B, respectively. As in the first embodiment, 13Ai (i = 1, 2, ..., k) and 13Bi (i = 1, 2, ..., k) are Halbach-arranged annular permanent magnet arrays attached to the rotor units 25A and 25B.

[0085] Reference numerals 14A and 14B denote circular upper and lower support plates. Shaft fixing mechanisms 26A and 26B for firmly fixing stationary shafts 21A and 21B are formed in the centers of the support plates 14A and 14B.

[0086] The positional relationship between the support plates 14A and 14B is determined and supported by a cylindrical support wall 27. This support wall 27 is attached to the flywheel rotating at high speed. Department It also plays a role in preventing debris from flying out to the outside in the unlikely event that the generator motor section 2 or the generator motor section 3 is damaged.

[0087] A light metal with high yield strength is selected as the material for the support plates 14A, 14B and the support defense wall 27. For example, extra super duralumin (A7075P) or a 6Al-4V titanium alloy is preferably used, and a 6Al-6V-2Sn titanium alloy or a 11.5Al-1Mo-6Zr-4.5Sn titanium alloy is even more preferably used.

[0088] Generally, in a ring with a large ratio of inner radius to outer radius (ratio > 0.6), the rotational stress generated in the circumferential direction is much higher than the rotational stress generated in the radial direction. This is the case for the rotating mass ring of the conventional and present integrated flywheel energy storage devices.

[0089] In the second embodiment, the CFRP rotating mass rings (9A, 9B) of the same specifications as those in the first embodiment are used, so the requirements of the first step of the design process described above are met, and the maximum mass energy density D is one order of magnitude higher than that of high-strength metal mass rings (SNCM439, etc.). fw (relative value) is obtained.

[0090] Furthermore, like the first embodiment, the second embodiment also employs an AFPM type generator motor unit 3 having rotor units 25A and 25B made of Halbach array magnet arrays, and the rotor units 25A and 25B are configured to be integrated with the flywheel hubs 22A and 22B, so that iron materials can be eliminated (removed or replaced with lightweight materials) from conventional bulk parts.

[0091] As a result, the second embodiment of the present invention is oth The requirement for the second step of the design process mentioned above has been met, and not only has the size been reduced, but the maximum device mass-energy density D sys (Effective for weight reduction) Improvements can also be achieved.

[0092] [Third embodiment] The third embodiment relates to the configuration of a flywheel electricity storage device of the present invention that is suitable for installation in a moving body (such as an automobile or an aircraft).

[0093] When an external force (such as gravity or mechanical force) acts on a rotating body that rotates at high speed, such as a flywheel, changing the angle of the rotation axis, a force is generated in the direction perpendicular to the external force (gyroscopic effect). If this force is generated in a flywheel power storage device, it can cause the problem of unstable running when the moving body changes direction up, down, left, or right. The third embodiment of the present invention can solve this problem.

[0094] 3 is a cross-sectional view of a flywheel electricity storage device 30 according to a third embodiment, cut along a central axis of rotation 4 (Z-axis). Flywheel electricity storage device 30 has a composite structure in which two identical flywheel electricity storage devices (a first flywheel electricity storage device 31 and a second flywheel electricity storage device 32) are stacked one above the other so that their central axes of rotation 4 are aligned.

[0095] Although the above embodiment has one each of the first flywheel capacitor 31 and the second flywheel capacitor 32, the number of the first flywheel capacitor 31 and the second flywheel capacitor 32 may be the same. The first flywheel capacitor 31 and the second flywheel capacitor 32 are driven to rotate in opposite directions at a constant speed.

[0096] The first flywheel electric storage device 31 corresponds to the first electric storage unit in the present invention, and the second flywheel electric storage device 32 corresponds to the second electric storage unit in the present invention. Hereinafter, the same reference numerals and descriptions as in the first embodiment will be omitted for the same components as those in the first embodiment.

[0097] 3, the disk-shaped central support plate 33 serves as both the lower support plate 14B of the first flywheel capacitor 31 and the upper support plate 14A of the second flywheel capacitor 32. 31 The lower bearing portion 15B of the second flywheel capacitor 32 is provided on the lower central surface thereof, and the lower bearing portion 15A of the second flywheel capacitor 32 is provided on the lower central surface thereof.

[0098] The material of the central support plate 33 is the same as that of the upper support plate 14A and the lower support plate 14B. A light metal with high yield strength is selected. For example, extra super duralumin (A7075P) or a 6Al-4V titanium alloy is preferable, and a 6Al-6V-2Sn titanium alloy or a 11.5Al-1Mo-6Zr-4.5Sn titanium alloy is even more preferable.

[0099] As described above, the flywheel energy storage device 30 according to the third embodiment is configured by stacking flywheel energy storage devices 31 and 32 of the same configuration that rotate at the same speed but in opposite directions. Therefore, even when the moving body travels (or sails) in a manner that changes the angle of the rotating shaft of the flywheel energy storage device 30, the gyroscopic effect force generated in the first flywheel energy storage device 31 is cancelled out by the second flywheel energy storage device 32 and becomes essentially zero.

[0100] In this way, a new effect can be achieved in that a mobile body equipped with the flywheel power storage device 30 can run (or sail) stably even when the moving direction (up, down, left, or right) is changed.

[0101] The flywheel energy storage device 30 according to the third embodiment has a stacked configuration of the flywheel energy storage devices according to the first or second embodiment, and therefore can achieve an extremely high mass energy density equivalent to that of the first or second embodiment.

[0102] [Fourth embodiment] Generally, a flywheel power storage device must be equipped with a bidirectional inverter to drive the generator motor (power supply and power reception). Strictly speaking, this inverter is also a component of the flywheel power storage device, so it is desirable to integrate the inverter unit with the flywheel unit and the generator motor unit in order to reduce the size of the flywheel power storage device including the inverter.

[0103] The flywheel electric energy storage device 40 of the fourth embodiment is designed to meet this demand.

[0104] 4 is a cross-sectional view of a flywheel energy storage device 40 according to the fourth embodiment, taken along the central axis of rotation 4 (Z-axis). The same components as those in the first embodiment are denoted by the same reference numerals, and their description will be omitted.

[0105] Reference numerals 41A and 41B denote the upper and lower support plates of the flywheel energy storage device 40. Like the support plates 14A and 14B of the first embodiment, they are connected to the upper and lower bearing portions at their centers, but differ from the first embodiment in that they are provided with annular recesses 42A and 42B that protrude toward the upper and lower flywheel hubs 8A and 8B between the rotating shafts 5A and 5B and the rotating mass circles 9A and 9B. The annular recesses 42A and 42B are formed to correspond to the annular spaces formed between the rotating shafts 5A and 5B and the rotating mass circles 9A and 9B.

[0106] The annular recesses 42A and 42B of the upper and lower support plates house bidirectional inverter units 43A and 43B that drive the generator motor unit 3. Furthermore, for example, if the bidirectional inverter unit 43B can be entirely accommodated in one annular recess 42B, there is no need to provide the other annular recess 42A, and in that case the upper support plate may remain the upper support plate 14 of the first embodiment.

[0107] As shown in FIG. 4, in a flywheel energy storage device 40 according to the fourth embodiment, support plates 41A and 41B are provided to partition the free space created by the integration of the flywheel unit 2 and the generator motor unit 3 of the first embodiment, and bidirectional inverter units 43A and 43B are housed in recesses 42A and 42B thereof, thereby achieving a high degree of integration in which the flywheel unit 2, the generator motor unit 3, and the bidirectional inverter units 43A and 43B are integrated together.

[0108] Furthermore, since a partition is provided between the flywheel unit 2 and the generator motor unit 3, which rotate at high speed, the bidirectional inverter units 43A and 43B, which are power electronics circuits, can operate stably without being subjected to thermomechanical influences from the flywheel unit 2 and the generator motor unit 3.

[0109] [Fifth embodiment] When the flywheel of a flywheel energy storage device is rotated at high speed, windage loss occurs between the flywheel surface and the atmosphere, reducing the rotation speed and the stored energy density. To prevent this, it is possible to install a vacuum exhaust device externally and evacuate the inside of the housing (in FIG. 1, the space surrounded by upper support plate 14A, lower support plate 14B, upper support defensive wall 16A, and lower support defensive wall 16B). In the case of such a flywheel energy storage device, the vacuum exhaust device is added to part of the system, which increases the volume by the amount of the vacuum exhaust device and reduces the degree of integration (degree of miniaturization) of the system.

[0110] The flywheel energy storage device 50 according to the fifth embodiment has been made to solve this additional problem, and uses the rotating shaft and internal empty space of the flywheel energy storage device 1, 20 according to the first or second embodiment to incorporate a well-known vacuum exhaust device (e.g., a spiral groove molecular pump) as an exhaust device.

[0111] 5 is a cross-sectional view of a flywheel energy storage device 50 according to a fifth embodiment, taken along the central axis of rotation 4 (Z-axis). The same components as those in the first embodiment are denoted by the same reference numerals, and their description will be omitted.

[0112] Reference numerals 51A and 51B denote an upper rotating shaft and a lower rotating shaft of the flywheel electricity storage device 50, and 51C denotes a coupling shaft. The upper rotating shaft 51A is supported by a detachable upper bearing portion 52A, and the lower rotating shaft 51B is supported by a detachable lower bearing portion 52B. The upper bearing portion 52A and the lower bearing portion 52B are provided with ventilation holes 53A and 53B.

[0113] The detachable upper and lower bearings 52A and 52B are fitted into and connected to circular openings 55A and 55B provided in the upper support plate 54A and the lower support plate 54B, respectively.

[0114] A removable upper partition 56A is attached to the upper support plate 54A, dividing the upper space between it and the upper flywheel hub 8A into a flywheel space 60 and an upper bearing side space 60A. The upper partition 56A has an opening in the center through which the upper rotating shaft 51A passes. Similarly, the lower support plate 54B has a flywheel space 60A that divides the lower space between it and the lower flywheel hub 8B. Ru Sky Between 60 and under A detachable lower partition 56B is attached to separate the bearing-side space 60B from the lower bearing-side space 60B.

[0115] 57A is an upper spiral groove molecular pump arranged in the upper space as an exhaust device, and is a spiral groove tapering 58A and a reverse tapered outside The spiral groove tapered ring 58A is fitted to a predetermined position on the upper rotating shaft 51A.

[0116] On the other hand, the reverse tapered outer sheath ring 59A may be fitted into the central opening of the upper partition 56A, or the ring may not be made and the side surface of the central opening of the upper partition 56A may be directly cut to form a reverse tapered outer sheath. outside sheath ring This is an example of direct formation of 59A.

[0117] 57B is a lower spiral groove molecular pump, 58B is a lower spiral groove tapered ring, and 59B is a lower reverse tapered outer sheath ring.

[0118] When the flywheel power storage device 50 is activated and the flywheel section 2 and rotating shafts 51A and 51B begin to rotate, the spiral groove molecular pumps 57A and 58B are activated, and the air in the flywheel space 60 is exhausted into the bearing-side spaces 60A and 60B. After a while, the flywheel space becomes a vacuum, and the bearing-side spaces become atmospheric pressure (outside air pressure). Because the flywheel space is maintained at a vacuum, windage loss that occurs on the flywheel surface can be eliminated.

[0119] In the fifth embodiment, the empty space of the flywheel power storage device 50 is utilized to house the external vacuum exhaust device, thereby reducing the volume of the vacuum exhaust device. This allows for a further increase in integration and a dramatic reduction in size.

[0120] [Sixth embodiment] The fourth embodiment shows a flywheel electricity storage device 40 in which bidirectional inverter units 43A and 43B are housed in the empty space that was previously present in the flywheel electricity storage device 1 of the first embodiment. On the other hand, the fifth embodiment shows a flywheel electricity storage device 50 in which spiral groove molecular pumps 57A and 58B, which are exhaust devices, are provided inside the housing of the flywheel electricity storage device 1 of the first embodiment to create a vacuum inside the housing.

[0121] In the sixth embodiment described next, both a bidirectional inverter unit and an exhaust device are housed in the empty space of the flywheel power storage device 1 of the first embodiment, thereby increasing the degree of integration (miniaturization).

[0122] 6 is a cross-sectional view of a flywheel energy storage device 70 according to the sixth embodiment, taken along the central axis of rotation 4 (Z-axis) 4. The same components as those in the first, fourth and fifth embodiments are denoted by the same reference numerals, and their description will be omitted.

[0123] The configuration of the flywheel energy storage device 70 above the central rotation plane 6 is the same as the upper half of the flywheel energy storage device 50 of the fifth embodiment, and the configuration of the flywheel energy storage device 70 below the central rotation plane 6 is the same as the lower half of the flywheel energy storage device 40 of the fourth embodiment.

[0124] A spiral groove molecular pump 57A is incorporated in the upper part, and a bidirectional inverter unit 43B is incorporated in the lower part.

[0125] When the generator motor unit 3 and the rotating shafts 51A and 51B start to rotate due to the power supply from the bidirectional inverter unit 43B, the spiral groove molecular pump 57A is activated and the air in the flywheel space 60 is exhausted into the bearing side space 60A. After a while, the flywheel space 60 becomes a vacuum and the bearing side space 60A becomes atmospheric pressure (outside air pressure). Because the flywheel space 60 is maintained at a vacuum, windage loss that occurs on the flywheel surface can be eliminated.

[0126] In the sixth embodiment, the free space of the flywheel power storage device 1 of the first embodiment is Spiral groove molecular pump Since the external vacuum exhaust device 57A and the bidirectional inverter unit 43B are housed in the external vacuum exhaust device 57A, the volumes of the external bidirectional inverter 57A and the external bidirectional inverter 43B can be reduced simultaneously, thereby achieving a higher integration level (miniaturization) than the first to fifth embodiments.

[0127] [Seventh embodiment] 5 showing the fifth embodiment equipped with spiral groove molecular pumps 57A and 57B, free spaces are found between the bearings 52A and 52B and the partitions 56A and 56B. The seventh embodiment utilizes these spaces to further increase the degree of integration (miniaturization).

[0128] 7 is a cross-sectional view of a flywheel energy storage device 80 according to the seventh embodiment, taken along the central axis of rotation 4 (Z-axis) 4. The same components as those in the first, fourth and fifth embodiments are denoted by the same reference numerals, and their description will be omitted.

[0129] Reference numeral 81A denotes an upper bidirectional inverter unit disposed in the annular upper bearing-side space 60A. The upper bidirectional inverter unit 81A is connected to the upper partition 56A or the upper support plate 54A. Similarly, reference numeral 81B denotes a lower bidirectional inverter unit disposed in the annular lower bearing-side space 60B. The lower bidirectional inverter unit 81B is connected to the lower partition 56A or the upper support plate 54A. B Or it is connected to the lower support board 54B.

[0130] When the generator motor unit 3 and the rotating shafts 51A, 51B, 51C begin to rotate due to power supplied from the bidirectional inverter units 81A, 81B, the spiral groove molecular pumps 57A, 57B are activated and the air in the flywheel space 60 is exhausted into the bearing-side spaces 60A, 60B. After a while, the flywheel space 60 becomes a vacuum and the bearing-side spaces 60A, 60B become atmospheric pressure (outside air pressure). Because the flywheel space 60 is maintained at a vacuum, this embodiment can eliminate windage loss that occurs on the surface of the flywheel unit 2 without the need for an external vacuum exhaust device.

[0131] In the seventh embodiment, the spiral groove molecular pumps 57A, 57B and the bidirectional inverter units 81A, 81B serving as exhaust devices are housed in the empty space of the flywheel power storage device 1 of the first embodiment, which makes it possible to simultaneously reduce the volumes of the external vacuum exhaust device and the external bidirectional inverter. This allows for a higher degree of integration (miniaturization) compared to the first to fifth embodiments. [Explanation of symbols]

[0132] 1, 10, 20, 30, 40, 50, 70, 80...Flywheel storage device 2...Flywheel section 3...Generator motor section 5A, 5B, 51A, 51B...Rotating shaft (support shaft) 8A, 8B, 22A, 22B...Flywheel hub 9A, 9B...Rotating mass circle 10,24...Stator section 11i...Coreless excitation induction coil 12A, 12B...Rotor section 13Ai, 13Bi...Permanent magnet array 21A, 21B...Stationary shaft (support shaft) 31...First flywheel capacitor (first storage unit) 32...Second flywheel capacitor (second storage unit) 43A, 43B...Bidirectional inverter section 57A, 57B... Spiral groove molecular pump (exhaust device)

Claims

1. A flywheel electricity storage device including a generator motor unit that converts electrical energy into rotational kinetic energy and vice versa, and a flywheel unit that stores energy as rotational kinetic energy, the flywheel unit includes a support shaft whose central axis coincides with the rotation axis of the flywheel unit, a pair of flywheel hubs coaxially supported on the support shaft, and annular rotating mass rings provided on the outer peripheries of the respective flywheel hubs; The generator motor unit includes a stator unit having an ironless excitation induction coil provided between the pair of flywheel hubs, and a rotor unit having a yokeless Halbach arrangement permanent magnet array that is held by each flywheel hub and faces the ironless excitation induction coil of the stator unit, and that is arranged so that magnetic flux is directed toward the ironless excitation induction coil, a housing that supports the support shaft and houses both the generator motor unit and the flywheel unit;

2. 2. The flywheel power storage device according to claim 1, wherein at least one of the flywheel hub, the support shaft, and the housing is made of a light metal or a carbon fiber reinforced plastic.

3. 3. The flywheel energy storage device according to claim 1, wherein an annular space is formed between the rotating mass circle of the flywheel section and the support shaft, and a bidirectional inverter section for supplying and receiving power to the generator motor section is housed in the annular space.

4. A flywheel energy storage device as described in any one of claims 1 to 3, characterized in that an exhaust device is provided inside the housing to evacuate at least the rotational areas of the generator motor section and the flywheel section inside the housing to create a vacuum.

5. a first power storage unit configured with the generator motor unit and the flywheel unit, and a second power storage unit configured with the generator motor unit and the flywheel unit that rotates in a reverse direction at a constant speed relative to the first power storage unit, 5. The flywheel electric power storage device according to claim 1, wherein the first electric power storage units and the second electric power storage units are arranged in equal numbers on the same rotation axis.

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