Three-dimensional contact-type spherical nanogenerator based on split electrode

Abstract

The application provides a three-dimensional contact type ball nanogenerator based on split electrodes, which comprises a spherical shell, a plurality of discs in the spherical shell, split electrodes attached to upper and lower surfaces of the discs, a plurality of equal parts into which each disc is divided averagely, two electrodes in a diagonal direction of each disc forming a power generation unit, a fiber film pasted on the split electrodes, microspheres with a polarity opposite to that of the fiber material placed on the fiber film, a circuit board with a plurality of rectifier bridges arranged at a bottom end in the spherical shell, and under the action of an external force, the microspheres move in a cavity of the spherical shell, rub against the fiber film, generate charges with a polarity opposite to that of the fiber film on the surface of the microspheres, change with the movement of the microspheres, and then output current to the outside, and the current generated by each power generation unit formed by two electrodes in a diagonal direction of each disc is superimposed through a rectifier circuit. The application is an energy collection device which can realize multi-directional energy collection, has high charge output and high durability.

Description

Technical Field

[0001] This invention relates to the field of energy conversion, and in particular to a three-dimensional contact spherical nanogenerator based on segmented electrodes, which can convert mechanical energy into electrical energy. Background Technology

[0002] Currently, the ocean, due to its vast and high-density energy reserves, has become one of the most commercially promising renewable energy sources. Strengthening the development of wave energy technology is beneficial to the sustainable development of marine natural resources. However, ocean waves are characterized by low frequency (typically less than 5Hz) and strong directional randomness. Therefore, developing a technology capable of efficiently and multidirectionally harvesting wave energy is crucial for wave energy harvesting.

[0003] Triboelectric nanogenerators (TENGs), as a highly efficient mechanical energy harvesting technology based on triboelectricity and electrostatic induction, have attracted widespread attention. When two different materials undergo contact and frictional separation under the action of an external force, different charges accumulate on their surfaces due to their different affinities for electrons. In this case, if electrode materials are attached to the surfaces of the two materials and connected by an external circuit, the charges induced on the electrode surfaces will flow in the circuit under the influence of the potential difference due to electrostatic induction, thus forming a current. If this contact process is continuously repeated, alternating current output can be generated. Based on this principle, TENGs can convert weak mechanical energy into electrical energy. Compared with electromagnetic generators, triboelectric nanogenerators have multiple advantages, including high electrical output under low-frequency drive, low cost, and lightweight design. First, TENGs are lightweight and can float on water, exhibiting high energy conversion efficiency under low-frequency drive, and are more adaptable to irregular and random mechanical motion. These advantages make them an ideal wave energy harvesting technology. The voltage of a triboelectric nanogenerator (TENG) is unaffected by frequency, while its current and power are proportional to frequency. It has a specific threshold frequency (typically 5 Hz) below which a triboelectric nanogenerator of the same size outputs more power than an electromagnetic generator. Therefore, TENGs are an ideal option for ocean wave frequencies below 5 Hz.

[0004] Since the initial proposal of TENGs, various TENG devices with different structures have been designed for wave energy harvesting, most of which employ sphere-within-sphere or multi-layered sphere rolling structures (PANG YK, CHEN SE, CHU YH, et al. Matryoshka-inspired hierarchically structured triboelectric nanogenerators for wave energy harvesting[J]. Nano Energy, 2019, 66). However, due to the randomness of wave direction, these structures face certain bottlenecks in multi-directional wave energy harvesting, failing to efficiently collect energy from waves in all directions. Furthermore, some structures sacrifice internal space to achieve multi-directional ocean energy harvesting, resulting in low space charge density. Therefore, it is necessary to develop TENG devices with high volumetric charge density and the ability to efficiently harvest multi-directional wave energy. Summary of the Invention

[0005] This invention provides a method for fabricating a three-dimensional contact spherical nanogenerator with electrode segmentation and a rectifier bridge, aiming to overcome the shortcomings of current wave energy harvesting devices (TENGs) which cannot efficiently harvest energy from all directions and have low output charge density. The device of this invention can efficiently harvest energy from multi-directional vibrations and swaying, and generate high charge output, opening up a new path for wave energy harvesting. When the spherical generator of this invention is placed on ocean waves, regardless of the direction from which the waves originate, the device can indiscriminately convert the mechanical energy of the waves into electrical energy output. In summary, this invention proposes a TENG device with high volume utilization, high charge output density, and efficient multi-directional wave energy harvesting capabilities.

[0006] The present invention can be achieved through the following technical solutions.

[0007] A three-dimensional contact-type spherical nanogenerator based on segmented electrodes includes a spherical shell with multiple equally spaced disks inside, forming a multi-layered space. Segmented electrodes are attached to the top and bottom of each disk, and each segmented electrode is divided into multiple equal parts. Fiber films are mounted on the electrodes on the upper and lower surfaces of the disks, and rolling microspheres with opposite electrical properties to the fiber material are mounted on the fiber films. A circuit board is located inside the shell, including multiple rectifier circuits. Under external force, the rolling microspheres move within the shell, rubbing against the fiber films. Charges with opposite electrical properties to the fiber films are generated on the surface of the rolling microspheres. Due to electrostatic induction, the induced charges in the electrodes change with the movement of the rolling microspheres, thereby outputting current. The currents generated by the power generation units composed of two electrodes on each diagonal are superimposed through the rectifier circuits.

[0008] Furthermore, the spherical shell is a spherical outer shell printed from resin material, and the disks are printed from resin plates and are arranged at equal intervals inside the spherical shell.

[0009] Furthermore, the upper and lower electrodes of each disk are divided into 4, 8, 16, or 32 equal parts, and the two electrodes in the diagonal direction form a power generation unit.

[0010] Furthermore, the material of the rollable microspheres is copper, aluminum, PP (polypropylene), PE (polyethylene terephthalate), PA (nylon), PVC (polyvinyl chloride), PVA (polyvinyl alcohol), PTFE (polytetrafluoroethylene), glass, FEP (fluorinated ethylene propylene copolymer), or silicone.

[0011] Furthermore, the diameter of the rollable microsphere is 1 mm to 20 mm.

[0012] Furthermore, the rollable microspheres and the fiber film have different triboelectric sequence.

[0013] Furthermore, the fiber film is made of wool, rabbit hair, PP (polypropylene), or cotton.

[0014] Furthermore, each segmented electrode is divided into a sector shape with a size of 11.25°, 22.5°, 45°, or 90°.

[0015] Furthermore, the two sector-shaped electrodes in the diagonal direction are electrically connected, and the load is connected in series between the two electrodes.

[0016] Furthermore, multiple power generation units composed of diagonal electrodes at the same position on each layer of the disk are connected to a rectifier circuit.

[0017] Furthermore, the electrodes can be divided into 4, 8, 16, or 32 equally divided sector shapes, and the number of rectifier bridges can be 2, 4, 8, or 16. The sector electrodes are preferably divided into 8 equal parts, and the number of rectifier bridges is preferably 4.

[0018] Compared with existing technologies, the beneficial effects of the present invention are as follows:

[0019] 1. The triboelectric nanogenerator of this invention has high charge density: This invention constructs a spherical structure with multi-layered units, where the friction material of each unit consists of microspheres and fiber materials. The microspheres within the device have extremely small diameters, ranging from 0.1 to 20 mm, preferably 5 mm. The microspheres are placed on a disk within the spherical shell, eliminating the need for special elastic connectors or insulating materials between them. Under external force, the microspheres slide freely on the fiber material. The friction between the microspheres and the fiber material transforms point-to-surface friction into three-dimensional surface friction, increasing the friction area and thus improving the volumetric charge density of the device. Regardless of the excitation direction, the transferred charge output of this device can reach approximately 430 nC, and the volumetric charge density of a single device can reach approximately 2.4 nC / cm³. 3 The short-circuit current can reach approximately 6.8 μA, and the peak power density is approximately 13 W / m². 3 Both the volume charge density and peak power density are higher than those reported in previous studies (e.g., Figure 6 As shown in the figure, multi-directional wave energy collection was successfully achieved.

[0020] 2. The triboelectric nanogenerator of this invention can be used for multi-directional energy harvesting: the upper and lower electrodes of each disk inside the spherical shell are divided into eight equal parts. Two electrodes in the diagonal direction form a power generation unit, with four power generation units per layer. Multiple power generation units formed by diagonal electrodes at the same position in each layer correspond to a rectifier bridge, and the four rectifier bridges are connected in parallel for output. The output performance of the device was tested at 360°. Regardless of the change in excitation angle, the overall output performance of the device remains unchanged. Traditional spherical power generation devices usually only divide the electrodes into two pieces, and the output performance reaches its maximum only at a specific angle. The spherical generator of this invention, through the combination of electrode division and rectifier bridges, makes the charge output direction of different power generation units the same, realizing the superposition of currents from multiple power generation units. The combination of electrode division and rectifier bridges allows the device to harvest wave energy from any direction without discrimination. Attached Figure Description

[0021] The above and other objects, features, and advantages of the present invention will become clearer from the accompanying drawings. The same reference numerals indicate the same parts throughout the drawings. The drawings are not intentionally drawn to scale with actual dimensions; the focus is on illustrating the gist of the invention.

[0022] Figure 1 This is a schematic diagram of a three-dimensional contact spherical nanogenerator structure based on segmented electrodes according to an embodiment of the present invention;

[0023] Figure 2 This is an exploded schematic diagram of the electrodes, fiber membrane, and spheres in a three-dimensional contact spherical nanogenerator according to an embodiment of the present invention.

[0024] Figure 3This is a schematic diagram of the rectifier bridge of a three-dimensional contact spherical nanogenerator according to an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the power generation process of a three-dimensional contact spherical nanogenerator according to an embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram showing the change of short-circuit current over time when a three-dimensional contact spherical nanogenerator is subjected to periodic external forces at different angles (0°, 45°, 90°) during implementation.

[0027] Figure 6 This is a schematic diagram comparing the three-dimensional contact spherical nanogenerator of this invention with various published omnidirectional space charge densities. Detailed Implementation

[0028] To enable those skilled in the art to better understand the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0029] like Figure 1 As shown, the three-dimensional contact spherical nanogenerator based on segmented electrodes in this embodiment is a triboelectric nanogenerator. This triboelectric nanogenerator is a spherical generator, including a spherical shell 1. The interior of the shell 1 is divided into multiple layers by multiple disks 2. Segmented electrodes are attached to the top and bottom of each disk 2 (each disk's upper and lower electrodes are divided into multiple equal parts; two electrodes diagonally form a power generation unit, and there are multiple power generation units). Fiber films 4 are provided on the electrodes on the upper and lower surfaces of the disks. Rollable microspheres 5 with opposite electrical charges to the fiber films 4 are filled on the fiber films 4. The microspheres 5 occupy approximately half the volume of the space. A circuit board 6 equipped with four rectifier bridges (connected to the power generation units in the four directions) is located at the bottom of the microspheres. Under external force, the microspheres 5 move within the shell 1, rubbing against the fiber films 4, generating charges on the surface of the microspheres 5 with opposite electrical charges to the fiber films 4. Due to electrostatic induction, the induced charges in the segmented electrodes 3 change with the movement of the microspheres 5, thereby outputting current. The currents generated by the power generation units composed of two electrodes on each diagonal are superimposed through a rectifier circuit.

[0030] The materials for the microspheres 5 can be selected from (but are not limited to) metals (such as copper, aluminum alloy, stainless steel, iron, aluminum), plastics (polypropylene, polyethylene terephthalate, nylon, polyvinyl chloride, polyvinyl alcohol, polytetrafluoroethylene), glass, other polymers (silicone, polydimethylsiloxane), etc., and can be solid or hollow.

[0031] The fiber film 4 can be made of a variety of materials, including wool, rabbit hair, PP (polypropylene), cotton and other materials.

[0032] In a preferred embodiment, the outer diameter of the spherical shell 1 ranges from 5 to 20 cm, preferably 7 cm, and the thickness is 2 mm. The microspheres 5 have extremely small diameters, ranging from 1 to 20 mm, preferably 5 mm.

[0033] As one specific embodiment, see Figure 1 In this embodiment, the generator comprises, from the outside in, a spherical outer shell 1 printed from resin material. The interior of the sphere is divided into multiple layers by seven resin-printed discs 2. Segmented electrodes 3 are attached to the top and bottom of each disc, with each disc's upper and lower electrodes divided into eight equal parts. Two electrodes on opposite diagonals form a power generation unit. A fiber film 4 is adhered to the electrodes 3 on the upper and lower surfaces of the discs. Rollable microspheres 5, with opposite polarity to the fiber film 4, are filled on the fiber film 4, with each microsphere occupying approximately half the volume of each layer. A circuit board 6 equipped with four rectifier bridges is located at the bottom of the spherical outer shell 1. Under external force, the microspheres 5 move within the cavity of the spherical outer shell 1, rubbing against the fiber film 4, generating charges on the surface of the microspheres 5 with opposite electrical polarity to the fiber film 4. Due to electrostatic induction, the induced charges in the segmented electrodes 3 change with the movement of the microspheres 5, thereby outputting current. The currents generated by the power generation units composed of two electrodes on each diagonal are superimposed through the rectifier circuit 6. The triboelectric nanogenerator provided by this invention is an energy harvesting device that can collect energy from multiple directions, has high charge output, and is highly durable. It can be applied to seawater wave energy harvesting.

[0034] The rollable microspheres 5 and the fiber film 4 can be any two materials with different triboelectric sequences, meaning they are at different positions in the triboelectric sequence, thus enabling them to generate contact charges on their surfaces during contact or friction. Conventional insulating materials all possess triboelectric properties and can be used as materials for preparing the microspheres and fiber film of this invention.

[0035] The fiber material of the fiber film 4 of this invention can be selected from various materials, including wool, rabbit hair, PP (polypropylene), cotton, etc. The selected material has the opposite polarity to the microspheres 5. In this embodiment, the preferred fiber material is PP (polypropylene) fiber.

[0036] The rolling microspheres 5 of this invention can be made of PTFE (polytetrafluoroethylene) microspheres, FEP (fluorinated ethylene propylene copolymer) microspheres, copper, aluminum, etc., with the selected material having the opposite polarity to the fiber material. In this embodiment, the preferred microspheres are PTFE (polytetrafluoroethylene) microspheres.

[0037] The spherical outer shell 1 of this invention is a closed structure fabricated by 3D printing, preferably with a diameter of 7 cm and a wall thickness of 2 mm. Inside the spherical outer shell 1, the diameters of the resin-printed disks 2, from bottom to top, are 44 mm, 60 mm, 65 mm, 68 mm, 65 mm, 60 mm, and 48 mm, respectively, and the disk thickness is preferably 1 mm. The distance between the disks is 7 mm.

[0038] In a preferred embodiment, the microspheres 5 are PTFE (polytetrafluoroethylene) microspheres with a diameter of 5 mm. PTFE microspheres are filled in the gaps between the plates inside the spherical shell 1, with a volume that is half the volume of the space (half the volume of the upper surface space of each layer of discs inside the microspheres 5).

[0039] The segmented electrodes 3 are made of materials such as silver, copper, and ITO, and are fan-shaped, with each fan-shaped electrode having an angle of approximately 45°. They are placed on a disc in a shape similar to a sliced ​​pizza. Eight fan-shaped electrodes matching the diameter of the disc 2 are attached to the upper and lower surfaces of each disc 2. The distance between two adjacent fan-shaped electrodes is approximately 0.5 mm. Two diagonally opposite fan-shaped electrodes are connected together with a conductive material. A load is connected in series between the two electrodes. In most cases, enameled wire is used to connect the two electrodes to the external circuit.

[0040] The rectifier bridge circuit used in this embodiment is of type MB10S, consisting of four rectifier bridges soldered onto a 2x2 circuit board, as shown below. Figure 3 As shown.

[0041] The following is based on Figure 4 Taking the triboelectric nanogenerator shown as an example, the preferred materials are PP fibers and PTFE microspheres. The power generation process of the triboelectric nanogenerator according to the present invention is described in detail.

[0042] 1. When external mechanical motion triggers the device's movement, the PTFE microspheres rub against the PP fibers on the flat electrode. During this friction process, the PTFE microspheres acquire a negative charge after initial friction, while the PP fibers acquire a positive charge. As the PTFE microspheres move from left to right, due to the potential imbalance, the negative charge on the surface of the PTFE microspheres gradually induces a positive charge on the right electrode. The positive charge flows from the left electrode to the right electrode, generating a current in the circuit until the PTFE microspheres completely cover the right electrode, at which point the current flow stops.

[0043] 2. When the PTFE ball moves from right to left, due to the potential imbalance, the positive charge in the electrodes transfers from the right electrode to the left electrode. If the ball is continuously subjected to external vibration or shaking, such as wave motion, it will continuously induce the transfer of free charges between the two electrodes, thereby generating alternating current and converting mechanical energy into electrical energy.

[0044] 3. Two sector-shaped electrodes on the diagonal form a group of power generation units. Multiple power generation units composed of diagonal electrodes at the same position on each layer are equipped with a rectifier bridge to form a superimposed DC output. Then, the four rectifier bridges are connected in parallel so that the current of all power generation units is superimposed.

[0045] This structure uses PTFE microspheres with a diameter of 5 mm and PP fibers. Figure 5 The test results show the variation of short-circuit current of the triboelectric nanogenerator over time at different angles. The measurements show that regardless of the excitation angle, the short-circuit current of the triboelectric nanogenerator is approximately 6.8 μA, and the space charge density can be as high as approximately 2.4 nC / cm³. 3 The instantaneous power density is approximately 13 W / m². 3 . Figure 6 This device demonstrates the highest space charge density and instantaneous power density among all-encompassing closed-cell TENG devices for omnidirectional wave energy harvesting to date. In complex marine environments, connecting multiple triboelectric nanogenerators into a network structure via wires can significantly improve the conversion efficiency of ocean wave energy.

[0046] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A three-dimensional contact-type spherical nanogenerator based on segmented electrodes, characterized in that, The device includes a spherical shell containing multiple equally spaced discs, forming a multi-layered space. Each disc has segmented electrodes attached to its top and bottom, each electrode being divided into multiple equal parts. Fiber films are mounted on the electrodes on the upper and lower surfaces of the discs, and rolling microspheres with opposite electrical properties to the fiber material are mounted on these films. A circuit board, including multiple rectifier circuits, is located inside the shell. Under external force, the rolling microspheres move within the shell, rubbing against the fiber films. This generates charges on the surface of the microspheres with opposite electrical properties to the fiber films. Due to electrostatic induction, the induced charges in the electrodes change with the movement of the rolling microspheres, thus outputting current. The currents generated by the power generation units composed of two electrodes on each diagonal are superimposed through the rectifier circuits.

2. The three-dimensional contact spherical nanogenerator based on segmented electrodes according to claim 1, characterized in that, The spherical shell is a spherical outer shell printed from resin material, and the discs are printed from resin plates and are arranged at equal intervals inside the spherical shell.

3. The three-dimensional contact spherical nanogenerator based on segmented electrodes according to claim 2, characterized in that, Each disk has its upper and lower electrodes divided into eight equal parts, and the two electrodes on the diagonal side form a power generation unit.

4. The three-dimensional contact spherical nanogenerator based on segmented electrodes according to claim 1, characterized in that, The materials of the rollable microspheres are copper, aluminum, PP (polypropylene), PE (polyethylene terephthalate), PA (nylon), PVC (polyvinyl chloride), PVA (polyvinyl alcohol), PTFE (polytetrafluoroethylene), glass, FEP (fluorinated ethylene propylene copolymer), and silicone.

5. The three-dimensional contact spherical nanogenerator device based on segmented electrodes according to claim 1, characterized in that, The diameter of the rollable microspheres is 1 mm to 20 mm.

6. A three-dimensional contact spherical nanogenerator based on segmented electrodes according to claim 1, characterized in that, The rollable microspheres and the fiber film have different triboelectric electrode sequences.

7. A three-dimensional contact spherical nanogenerator based on segmented electrodes according to claim 1, characterized in that, The fiber film is made of wool, rabbit hair, PP (polypropylene), or cotton.

8. A three-dimensional contact spherical nanogenerator based on segmented electrodes according to any one of claims 1 to 7, characterized in that, Each segmented electrode can be divided into a sector shape with a size of 11.25°, 22.5°, 45°, or 90°.

9. A three-dimensional contact spherical nanogenerator based on segmented electrodes according to claim 8, characterized in that, Two sector-shaped electrodes on opposite sides are electrically connected, and the load is connected in series between the two electrodes.

10. A three-dimensional contact spherical nanogenerator based on segmented electrodes according to claim 9, characterized in that, Multiple power generation units, consisting of diagonal electrodes at the same position on each layer of the disk, are connected to a rectifier circuit.

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