CN114710059B - A friction nanogenerator for harvesting wind energy - Google Patents

Abstract

The invention discloses a friction nano generator for collecting wind energy. The friction nano generator structure comprises a base, a bracket, a rotating shaft, fan blades and an internal friction power generation unit. The fan blades are detachable and hollow, and each fan blade is internally provided with an array type cylindrical groove with two communicated ends. The friction power generation unit required by power generation is arranged in the cylindrical groove in the fan blade and isolated from the external environment. The fan blade of the friction generator can rotate around the shaft under the drive of wind, water drops, water waves and other forces, so that the dielectric material solid ball inside the fan blade rolls back and forth along the direction vertical to the rotating shaft and periodically contacts and separates with the electrode pair fixed in the cylindrical groove, thereby realizing friction power generation. The friction nano generator for collecting wind energy has the advantages of stable structure, reliable output performance, good durability, suitability for various working environments such as sunny and rainy days, capability of being used for collecting water drop energy and water wave energy at the same time, and realization of more efficient environmental energy collection.

Description

A friction nanogenerator for harvesting wind energy

Technical Field

The present invention relates to a novel structured triboelectric nanogenerator (TENG) that can be used for harvesting environmental energy such as wind energy, water drop energy, and water wave energy. It is mainly used in the fields of micro-nano energy, nanogenerators, and self-powered sensors.

Background technique

At present, the device structures that use friction power generation technology for wind energy collection are mainly divided into two categories. One is the friction nanogenerator based on a rotating structure. The friction nanogenerator of this type of structure uses a wind cup or wind turbine structure to first convert wind energy into rotational mechanical energy, and then installs the positive and negative friction layers on the rotor and stator respectively to achieve periodic contact and separation of the friction layers during the rotation process, thereby realizing friction power generation to convert the rotational mechanical energy into electrical energy. This structure has the advantages of high output performance and a high correlation between the output electrical signal and wind speed, and has more advantages in realizing self-powered sensing; and because the structure is similar to an electromagnetic generator, it is easier to integrate with other energy collection methods such as electromagnetic power generation and solar power generation, thereby realizing composite energy collection. However, this structure also has the disadvantages of large size, high cost, complex process, poor ability to collect weak wind energy, and greater impact from environmental humidity.

The other type is a friction nanogenerator that harvests wind energy based on a flutter structure. The structure is mainly composed of a flutter plate that moves under the action of wind and a fixed rigid plate. Frictional power generation is achieved through the contact and separation between the flutter plate and the fixed upper and lower electrodes. The flutter plate is often made of flexible materials such as silk fabrics and film structures. This type of wind energy harvesting friction nanogenerator has the characteristics of simple process, small size, ability to harvest tiny wind energy, and greater convenience for large-scale integration. However, due to the characteristics of wind-induced vibration, this structure has the disadvantages of unstable output signal, rapid loss of flutter plate, and great influence of environmental humidity.

Summary of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art and provide a friction nanogenerator for collecting wind energy.

In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

The friction nanogenerator structure includes five parts: a base, two brackets, a rotating shaft, three blades and a friction power generation unit. The two brackets are fixed at both ends of the base, and the two ends of the rotating shaft are rotatably supported on the two brackets through deep groove ball bearings. The three blades are fixed on the rotating shaft, and the angle between any two blades is 120°. The blades are composed of two identical half blades, and the two sides of the half blades are provided with connecting grooves, and the inner surface is provided with a plurality of array-type semi-cylindrical grooves, and the inner surface between the two connecting grooves is provided with a plurality of array-type semi-cylindrical grooves, and two electrodes insulated from each other are coated on the surface of each semi-cylindrical groove and the connecting groove, and a friction layer is coated on the groove part of the electrode. When the two half blades are relatively fixed, a plurality of cylindrical grooves isolated from the external environment are formed inside the blades, and a plurality of solid balls of dielectric materials are placed in each cylindrical groove, and the electrodes of each groove are connected in series through the connecting groove to form a friction power generation unit; the friction power generation units of the three blades are connected in parallel and connected to external equipment. Furthermore, the cylindrical groove is perpendicular to the shaft to ensure the reciprocating motion of the solid ball of dielectric material. A flange connection is provided at every 120° in the middle of the shaft. The entire structure has three flange connections in total. The three blades correspond to the three flange connections one by one and are fixed to the shaft through the flange structure. The design of the three blades can ensure the stability of the friction nanogenerator system during rotation.

Furthermore, the rotating shaft described in the present invention is a hollow shaft and has a through hole 15 overlapping with the axis. Both ends of the flange structure of each fixed fan blade on the rotating shaft are respectively provided with a connecting hole 16, which is connected to the through hole 15. This design is to bring together the output ends of the friction nanogenerators located in the fan blades, and finally lead them out from the axis position where the angular velocity at both ends of the rotating shaft is 0, so as to facilitate performance testing and energy storage; the rotating shaft as a whole is rotatably supported on two brackets through a deep groove ball bearing rotating shaft, thereby reducing the resistance during the rotation of the rotating shaft.

The beneficial effect of the present invention is that the friction nanogenerator is specially designed for the fan blade structure, so that the wind energy collection friction nanogenerator of the new structure achieves the following three beneficial effects: the special fan blade structure isolates the external environment and the friction power generation unit, greatly reducing the influence of air humidity on the wind energy collection friction nanogenerator, so that the fan blade can rotate under the action of wind or water droplets and water waves to collect wind energy, water droplet energy and water wave energy, and can work normally on sunny and rainy days; it is more convenient to realize a composite energy collection system, which can be integrated with energy collection methods such as solar power generation, hydropower, and electromagnetic power generation to better collect energy in the environment; and the performance of the friction nanogenerator of the present invention is stable, the output signal is reliable, and the TENG of this structure is more sensitive to wind speed and can work at a low wind speed of 3m/s, which greatly improves the environmental energy utilization rate and is conducive to achieving the advantages of low wind speed energy collection and self-powered sensing.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is further described below in conjunction with the accompanying drawings and embodiments;

Fig. 1 is an overall structural diagram of the present invention;

Figure 2 is a structural diagram of half a fan blade;

Figure 3 is an enlarged cross-section of the entire fan blade;

FIG4 is an enlarged longitudinal section of the friction layer in the cylindrical groove;

FIG5 is a structural diagram of a rotating shaft;

FIG6 is a structural diagram of a bracket;

Explanation of the accompanying drawings: base 1, bracket 2, bracket 3, first screw 4, deep groove ball bearing 5, half a fan blade 6, rotating shaft 7, second screw 8, third screw 9, semi-cylindrical groove 10, connecting groove 11, electrode 12, friction layer 13, solid ball of dielectric material 14, through hole 15, connecting hole 16.

Detailed ways

As shown in FIG1 , there are three blades in total, and the design itself is to convert wind energy into mechanical energy and provide power for the contact and separation of the positive and negative friction layers. As shown in FIG2 , the blade can be disassembled from the side into two identical half blades 6, and a connecting groove 11 is opened on both sides of the half blade 6, and a plurality of array-type semi-cylindrical grooves 10 are opened on the inner surface between the two connecting grooves 11. Two electrodes 12 insulated from each other are coated on the surface of each semi-cylindrical groove 10 and the connecting groove 11, and a friction layer 13 is coated on the groove part of the electrode 12. When the two half blades 6 are relatively fixed, a plurality of cylindrical grooves isolated from the external environment are formed inside the blade, and a plurality of solid balls 14 of dielectric material are placed in each cylindrical groove. The electrodes 12 of each semi-cylindrical groove 10 are connected in series through the connecting groove 11 to form a friction power generation unit; the friction power generation units of the three blades are connected in parallel and connected to external equipment. The fixed whole fan blade isolates the influence of the external environment on the friction power generation unit placed in the internal cylindrical groove, providing a stable environment for the friction power generation process while reducing the weight of the fan blade, making the fan blade more sensitive to wind energy.

The friction power generation unit in the internal groove of the blade in the embodiments shown in Figures 3 and 4 is also the core of the friction nanogenerator, which adopts a dielectric independent layer mode. In order to maximize the contact area, reduce resistance, and improve the sensitivity of the friction layer 13 to contact and separate with the change of external wind energy, the structure of the friction layer 13 is shown in Figure 3. The solid ball 14 of dielectric material is placed in the semi-cylindrical groove 10. As the blade rotates, it rolls back and forth on the surface of the friction layer 13 to cause friction, thereby generating friction charges on the surface of the friction layer 13 and the solid ball 14 of dielectric material. The position change of the charged solid ball 14 of dielectric material forms a potential difference on the electrode 12 on the back of the friction layer 13, driving the flow of electrons in the external circuit to generate electricity. Considering that the greater the difference in the ability of the friction layer 13 to gain and lose electrons, the more charges generated by friction, and the better the performance of the friction generator, a nylon 66 (PA66) film with strong electron loss ability is selected as the friction layer 13, a solid ball 14 of a polytetrafluoroethylene (PTFE) dielectric material with strong electron gain ability and easier to move with the fan blade is selected, and metal Al is selected as the electrode 12. A uniform metal film layer such as Al is formed on the inner surface of the cylindrical groove by magnetron sputtering, atomic layer, etc. as the electrode 12. Two electrodes 12 are set in each pipeline, and the distance range of the electrodes 12 is adjustable. The solid ball 14 of the dielectric material rolls back and forth on the surface of the friction layer 13 during the rotation of the fan blade, increasing the contact area and achieving more sufficient contact. In addition, when the solid ball 14 of the dielectric material is away from and close to the rotating shaft 7, the change in its position causes the center of gravity of the fan blade to shift, which promotes the rotation of the fan blade and ensures that the friction power generation process of contact separation is continuously circulated.

In the embodiment shown in FIG5 , in order to facilitate the disassembly and assembly of the fan blades, the performance test of the friction nanogenerator and the energy storage, the rotating shaft 7 is specially designed. The rotating shaft 7 is a hollow shaft with a through hole 15 that coincides with the axis. A flange connection is provided at every 120° in the middle of the rotating shaft 7. The entire structure has a total of three flange connections. The three fan blades correspond to the three flange connections one by one and are fixed to the rotating shaft 7 through the flange structure. There is a connecting hole 16 at each end of each flange connection. The friction nanogenerators on the three fan blades can be collected in the through hole 15 of the rotating shaft through the connecting hole 16, and finally drawn out from the axis of the two ends of the rotating shaft 7 where the angular velocity is 0, so as to facilitate performance testing and connection of electrical equipment. The two ends of the rotating shaft 7 are fixed to the bracket through deep groove ball bearings 5. The spherical deep groove bearing 5 greatly reduces the friction force during the rotation of the rotating shaft 7, so that the wind energy collection device can collect wind energy in the environment more sensitively.

As shown in FIG6 , the bracket comprises a fixedly connected lower bracket 2 and an upper bracket 3 , and both the lower bracket 2 and the upper bracket 3 are provided with a semicircular groove matched with a deep groove ball bearing 5 for connecting the output end of the friction nanogenerator with the electrical equipment.

The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims (4)

1. A friction nanogenerator for collecting wind energy, characterized in that it comprises a base (1), two brackets, a rotating shaft (7) and three blades; the two brackets are fixed at two ends of the base (1), the two ends of the rotating shaft (7) are rotatably supported on the two brackets through deep groove ball bearings (5), the three blades are fixed on the rotating shaft (7), and the angle between any two blades is 120°; the blades are composed of two identical half blades (6), and the two sides of the half blade (6) are provided with connecting grooves (11), and the two connecting grooves (11) are connected to each other. A plurality of array-type semi-cylindrical grooves (10) are formed on the inner surface between the two blades, two electrodes (12) insulated from each other are coated on the surface of each semi-cylindrical groove (10) and the connecting groove (11), and a friction layer (13) is coated on the groove portion of the electrode (12). When the two half blades (6) are relatively fixed, a plurality of cylindrical grooves isolated from the external environment are formed inside the blades, and a plurality of solid balls (14) of dielectric material are placed in each cylindrical groove to form a friction power generation unit; the friction power generation units of the three blades are connected in parallel and connected to external equipment. 2. A friction nanogenerator for collecting wind energy according to claim 1, characterized in that the cylindrical groove inside the fan blade (6) is perpendicular to the rotating shaft (7); and the connecting groove (11) is parallel to the rotating shaft (7) and connected to the external air. 3. A friction nanogenerator for collecting wind energy according to claim 1, characterized in that the rotating shaft (7) is a hollow shaft, the hollow part is a through hole (15) overlapping the center of the rotating shaft, and there are three flange structures on the rotating shaft (7) for fixing the fan blades, and each flange structure has a connecting hole (16) at both ends; the connecting hole (16) is connected to the through hole (15) on the main body of the rotating shaft (7), so that the output ends of the friction power generation units on the three fan blades are collected in the through hole (15) of the hollow shaft through the connecting hole (16), and are led out at the axial position where the angular velocity at both ends of the rotating shaft (7) is 0. 4. A friction nanogenerator for collecting wind energy according to claim 1, characterized in that the bracket comprises a lower bracket (2) and an upper bracket (3) fixedly connected, and the lower bracket (2) and the upper bracket (3) are both provided with a semicircular groove that cooperates with a deep groove ball bearing (5).