FLYWHEEL

TECHNICAL FIELD

[0001] The present invention relates generally to energy storage systems and particularly to energy storage systems having solar panels and a flywheel.

BACKGROUND

[0002] Various green energy technologies are known, such as wind turbine and solar panels. A wind turbine is a power-generation device that transforms the kinetic energy of the wind into rotational kinetic energy which in turn causes an electrical generator to rotate to thereby convert the rotational kinetic energy into electrical energy. A wind turbine may have a horizontal axis of rotation or a vertical axis of rotation. In a typical horizontally arranged wind turbine, there is a ground- based tower supporting a nacelle that houses the electrical generator and a gearbox attached to a shaft. The shaft is, in turn, connected a rotor to which are attached multiple blades. The wind turbine may include a yaw mechanism to permit the wind turbine to rotate in a horizontal plane to account for different wind directions.

[0003] A recurring issue with wind turbines, particularly large wind turbines, is that wind is intermittent and thus at times of no wind or insufficient wind speed the wind turbine will stop turning. Because the torque needed to restart the rotation of the idle blades and rotor is significant, the wind turbine may remain inoperative at low wind speeds, thus making the wind turbine less productive. Wind turbines also must be shut down when the wind speeds are too high. Thus, wind turbine technology may be limited for many places on earth.

[0004] Solar panel technology may also be quite limited in those places where sunlight is infrequent. Batteries may be used to store the collected energy but storage capacities of these batteries may be affected by cold temperatures.

[0005] It would be desirable to provide a novel energy storage technology to address at least some of these technical shortcomings. Such a technology is disclosed in the present specification and illustrated in the drawings. SUMMARY

[0006] The following presents a simplified summary of some aspects or embodiments of the invention in order to provide a basic understanding of the invention. This summary is not an extensive overview of the invention. It is not intended to identify key or critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some embodiments of the invention in a simplified form as a prelude to the more detailed description that is presented later.

[0007] Accordingly, one inventive aspect of the present disclosure is an energy storage system including a housing structure having walls and a roof and a plurality of photovoltaic cells disposed on the roof that are capable of generating electrical energy from sunlight. The system includes four sets of batteries inside the housing structure for storing the electrical energy generated by the photovoltaic cells. The system includes a first electric motor located inside the housing structure and connected to a first of the four sets of batteries, the first electric motor being connected to a first reduction gearbox. The system includes a second electric motor located inside the housing structure and connected to a second of the four sets of batteries, the second electric motor being connected to a second reduction gearbox. The system includes a third electric motor located inside the housing structure and connected to a third of the four sets of batteries, the third electric motor being connected to a third reduction gearbox. The system includes a fourth electric motor located inside the housing structure and connected to a fourth of the four sets of batteries, the fourth electric motor being connected to a fourth reduction gearbox. The system includes a flywheel and a belt driven by the first, second, third and fourth electric motors and mechanically engaged with the flywheel to rotate the flywheel.

[0008] Another inventive aspect of the present disclosure is a power-generation system comprising a wind turbine and an energy storage system for the wind turbine, the system including a housing structure having walls and a roof and a plurality of photovoltaic cells disposed on the roof that are capable of generating electrical energy from sunlight. The system includes four sets of batteries inside the housing structure for storing the electrical energy generated by the photovoltaic cells. The system includes a first electric motor located inside the housing structure and connected to a first of the four sets of batteries, the first electric motor being connected to a first reduction gearbox. The system includes a second electric motor located inside the housing structure and connected to a second of the four sets of batteries, the second electric motor being connected to a second reduction gearbox. The system includes a third electric motor located inside the housing structure and connected to a third of the four sets of batteries, the third electric motor being connected to a third reduction gearbox. The system includes a fourth electric motor located inside the housing structure and connected to a fourth of the four sets of batteries, the fourth electric motor being connected to a fourth reduction gearbox. The system includes a flywheel and a belt driven by the first, second, third and fourth electric motors and mechanically engaged with the flywheel to rotate the flywheel.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Further features and advantages of the present invention will become apparent from the following detailed description, taken in combination with the appended drawings in which:

[0010] FIG. 1 depicts an energy storage system in accordance with an embodiment of the present invention.

[0011] FIG. 2 depicts an energy storage system for a wind turbine in accordance with another embodiment of the present invention.

[0012] FIG. 3 depicts further details of the energy storage system of FIG. 1.

[0013] FIG. 4 depicts an energy storage system for supplying electrical power to a factory in accordance with another embodiment of the present invention.

[0014] It will be noted that throughout the appended drawings, like features are identified by like reference numerals.

DETAILED DESCRIPTION [0015] FIG. 1 depicts an exemplary energy storage system in accordance with an embodiment of the present invention.

[0016] The energy storage system is generally designated by reference numeral 10 in FIG. 1 . The energy storage system 20 as depicted in FIG. 1 , and which is shown in further detail in FIG. 3, includes a housing structure 30 having walls 32 and a roof 34. The energy storage system includes a plurality of photovoltaic cells (solar cells) 36 disposed on the roof that are capable of generating electrical energy from sunlight.

[0017] In the embodiments illustrated by way of example in FIG. 1 , and as shown in further detail in FIG. 3, there are a plurality (e.g. four) sets of batteries 40, 42, 44, 46 inside the housing structure for storing the electrical energy generated by the photovoltaic cells. Each set of batteries forms a battery bank. For example, in one specific implementation, there are 50 batteries per set for a total of 200 batteries although it will be appreciated that the number of batteries and the number of sets of batteries may be varied. The batteries are rechargeable batteries which may be lithium polymer, nickel cadmium, lead-acid, nickel metal hydride, lithium-ion, etc. In the embodiment illustrated by way of example in FIG. 1 , and as further shown in FIG. 3, a first electric motor 50 is located inside the housing structure and electrically connected to a first of the four sets of batteries. The first electric motor is mechanically connected to a first reduction gearbox 52. The system also includes a second electric motor 60 located inside the housing structure and electrically connected to a second of the four sets of batteries. The second electric motor is mechanically connected to a second reduction gearbox 62. The system includes a third electric motor 70 located inside the housing structure and electrically connected to a third of the four sets of batteries. The third electric motor is mechanically connected to a third reduction gearbox 72. The system also includes a fourth electric motor 80 located inside the housing structure and electrically connected to a fourth of the four sets of batteries. The fourth electric motor is mechanically connected to a fourth reduction gearbox 82. The system includes a flywheel 90 and a belt 100 driven by the first, second, third and fourth electric motors and mechanically engaged with the flywheel to rotate the flywheel. In the embodiment depicted in FIG. 2, the flywheel 90 has an output shaft 1 10. In the embodiment illustrated in FIG. 2, the output shaft 1 10 is horizontally disposed and connected to, and driven by, the flywheel 90. In one embodiment there may be two horizontal output shafts 1 10 extending from each side of the flywheel 90. Each shaft may be connected to a generator in one optional implementation.

[0018] As shown by way of example in FIG. 2, the energy storage system may be operatively connected to a wind turbine 20, e.g. a wind turbine with a horizontal axis of rotation 21 such as the one shown by way of example in FIG. 2. It will be appreciated that the energy storage system may be adapted to work with other types of wind turbines such as, for example, a wind turbine with a vertical axis of rotation. The wind turbine depicted by way of example in FIG. 2 has a tower 22, a nacelle 23 housing a generator 24 that rotates on a turbine shaft 25 connected to a rotor 26. The rotor has a plurality of blades 27.

[0019] In the embodiment depicted in FIG. 2, the output shaft (vertical shaft) is connected to an auxiliary electrical generator 1 12 to generate electrical power that is delivered by wires 29 to a motor 28 that can be used to start the turbine. Alternatively, the auxiliary electrical generator 1 12 can deliver the electrical power into the power grid, to the sets of batteries 40, 42, 44, 46, or to any other electrical energy storage device or other electrical equipment. The electrical generator 1 12 may include a stator and a rotor with magnets to generate electrical current.

[0020] In another embodiment, the output shaft 90 is mechanically connected to the turbine shaft of the wind turbine to mechanically drive the turbine shaft, rotor and blades of the wind turbine. The output shaft may be mechanically connected via a power-transmission mechanism to mechanically drive the turbine shaft, rotor and blades. This mechanism can be used to start up the turbine. For example, in the illustrated embodiment, the power-transmission mechanism can include a first set of gears, a horizontal drive shaft, a second set of gears, a vertical drive shaft and a torque-applying mechanism to apply torque to the turbine shaft.

[0021] In the illustrated embodiments of FIGS. 1 and 3, the flywheel is oriented to rotate in a vertical plane (i.e. about a horizontal axis of rotation) although in other embodiments the flywheel may be oriented in a different direction, e.g. horizontally. In embodiments that are believed to work best, the flywheel has a mass of between 30 and 40 tonnes, e.g. approximately 35 tonnes. In embodiments that are believed to work best, the flywheel has a diameter of between 6 and 8 meters, e.g. approximately 7 meters. In embodiments that are believed to work best, the flywheel is adapted to rotate efficiently at 15-20 RPM.

[0022] In embodiments that are considered to work best, each of the first, second, third and fourth gearboxes provides a gear ratio of 1 : 100. For example, in one specific implementation, the motor drive shafts (input to the gearboxes) rotate at 1500-2000 RPM and the flywheel rotates at 15-20 RPM. In another embodiment, there may be a plurality of smaller flywheels instead of the one large flywheel.

[0023] The flywheel may be rotationally supported by a bearing support mechanism comprising ball bearings or roller bearings. Alternatively, the flywheel may be rotationally supported by magnets or electromagnets to provide full or partial elevation, levitation or suspension of the flywheel. The magnets may be any suitable type of magnets, including for example supermagnets or liquid magnets. In addition, in one embodiment, there may be one or more electro-magnets to provide traction for the belts as needed.

[0024] In one optional embodiment, the energy storage system includes a microcontroller or microprocessor implementing in either hardware or software a control algorithm for controlling the power output by the electric motors. The microcontroller can control the speed of rotation of the flywheel by adjusting the power output by the motors. The microcontroller may also receive one or more signals from one or more battery monitoring circuits that indicate to the microcontroller how much energy is stored in the batteries. For example, if the batteries are full, i.e. at maximum storage capacity, the microcontroller may increase the power output of the motor to thus increase the angular velocity of the flywheel, i.e. to increase the kinetic energy stored in the flywheel.

[0025] In the embodiment depicted in FIG. 4, the energy storage system 10 delivers electrical power to a factory 120 or to any other electrically powered industrial facility, plant, device or apparatus. The energy storage system 10 can be situated at or near the factory 120 and can collect and convert solar energy into rotational kinetic energy stored in the flywheel. Unlike batteries, the flywheel is not affected by cold weather.

[0026] In a further embodiment, the energy storage system 10 may be onboard a boat or ship, collecting solar energy and storing the energy in the flywheel for powering the boat or ship.

[0027] It is to be understood that the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a device" includes reference to one or more of such devices, i.e. that there is at least one device. The terms "comprising", "having", "including", "entailing" and "containing", or verb tense variants thereof, are to be construed as open-ended terms (i.e., meaning "including, but not limited to,") unless otherwise noted. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of examples or exemplary language (e.g. "such as") is intended merely to better illustrate or describe embodiments of the invention and is not intended to limit the scope of the invention unless otherwise claimed.

[0028] While several embodiments have been provided in the present disclosure, it should be understood that the disclosed systems and methods might be embodied in many other specific forms without departing from the scope of the present disclosure. The present examples are to be considered as illustrative and not restrictive, and the intention is not to be limited to the details given herein. For example, the various elements or components may be combined or integrated in another system or certain features may be omitted, or not implemented.

[0029] In addition, techniques, systems, subsystems, and methods described and illustrated in the various embodiments as discrete or separate may be combined or integrated with other systems, modules, techniques, or methods without departing from the scope of the present disclosure. Other items shown or discussed as coupled or directly coupled or communicating with each other may be indirectly coupled or communicating through some interface, device, or intermediate component whether electrically, mechanically, or otherwise. Other examples of changes, substitutions, and alterations are ascertainable by one skilled in the art and could be made without departing from the inventive concept(s) disclosed herein.