Spherical non-contact friction nanometer generator capable of efficiently collecting low-frequency wave energy

Abstract

The invention discloses a spherical non-contact friction nanometer generator capable of efficiently collecting low-frequency wave energy, and relates to the field of wave energy collection. The spherical non-contact friction nanometer generator is composed of a stator and a rotor, and the stator and the rotor respectively correspond to an outer spherical shell and an inner spherical shell of a concentric sphere. The copper electrode on the inner surface of the outer spherical shell and the polytetrafluoroethylene (PTFE) film on the outer surface of the inner spherical shell form non-contact TENG, and mechanical energy is converted into electric energy. Wave energy which is widely distributed, low in frequency and irregular in peak value can be collected to supply power to small electronic equipment. The provided non-contact TENG which is low in cost, simple in structure and stable in performance provides a feasible scheme for collecting / utilizing irregular wave energy, and the non-contact TENG has important practical significance.

Description

Technical Field

[0001] The invention relates to the field of wave energy collection, and in particular to a spherical non-contact friction nanogenerator with high durability and high efficiency for collecting low-frequency wave energy. Background Art

[0002] The massive consumption of fossil fuels has brought about a heavy economic burden, severe energy crisis and long-term greenhouse effect, prompting people to find and use clean and environmentally friendly new energy. There are abundant types of renewable energy in the world. The ocean, which accounts for about 71% of the total area of ​​the earth, contains a large amount of renewable blue energy worth exploring, including wave energy and tidal energy. Among them, wave energy has many advantages such as green environmental protection, strong energy storage capacity, sustainability, wide distribution and strong predictability, and has great development significance.

[0003] In the current field of wave energy collection, traditional electromagnetic generators based on Faraday's law of electromagnetic induction are the mainstream wave energy collectors. Since the output power of traditional electromagnetic generators is proportional to the square of the frequency, a high and stable operating frequency is required to obtain effective output. Waves are high-entropy, low-frequency energy, which greatly limits the application of conventional electromagnetic generators. It is urgent to develop new wave energy collection technologies. The friction nanogenerator (TENG), which has developed rapidly in recent years, is based on triboelectric and electrostatic induction effects. It has high applicability for low-frequency and low-amplitude energy collection, and has revolutionary significance in the efficient realization of large-scale wave energy collection. It is an important direction for future offshore power generation.

[0004] TENG has been widely used in various forms of environmental mechanical energy collection, such as mechanical vibration, walking, raindrops, etc. In terms of wave energy collection, TENGs with different structures such as spherical, pendulum, buoy, and seesaw have been proposed. Among them, the contact-separation working mode of TENG based on direct contact of friction electrodes is currently the most widely used. However, continuous mechanical contact will cause wear and interface heating between friction electrodes, which will lead to reduced durability and output performance attenuation of TENG. Summary of the invention

[0005] The purpose of the present invention is to provide a spherical non-contact friction nanogenerator that efficiently collects low-frequency wave energy in response to the above problems. The spherical structure is adopted, and the outer spherical shell and the inner spherical shell are used as the stator and the rotor respectively to form a non-contact friction nanogenerator, which improves the durability and energy conversion efficiency, can convert wave energy into electrical energy, and can directly power small electronic devices after rectification. The friction nanogenerator involved in the present invention has a simple structure and stable performance. It is suitable for environments that require long-term stable operation and are difficult to perform routine maintenance, and has certain practical value.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme:

[0007] A spherical non-contact friction nanogenerator for efficiently collecting low-frequency wave energy, the components include an outer spherical shell, an inner spherical shell, a swing component, a bearing, a shaft, and a counterweight, wherein the friction power generation unit capable of converting mechanical energy into electrical energy is non-contact.

[0008] The outer spherical shell, composed of two identical hollow hemispheres, serves as the stator; the interface between the two hollow hemispheres is sealed and fixed to prevent water from entering the interior of the sphere;

[0009] The inner spherical shell, which is also composed of two identical hollow hemispheres, serves as a rotor and is arranged inside the outer spherical shell and can rotate freely inside the outer spherical shell; the interface between the two hollow hemispheres is sealed and fixed to prevent water from entering the interior of the sphere;

[0010] A swing assembly is fixed to the bottom of the inner spherical shell and is used to increase the swing effect of the inner spherical shell under the action of waves;

[0011] A counterweight block is provided on the swing assembly to lower the center of gravity of the entire device;

[0012] The bearing and the shaft are arranged between the outer spherical shell and the inner spherical shell to ensure that the inner spherical shell can rotate smoothly inside the outer spherical shell;

[0013] The friction power generation unit includes two friction generators with exactly the same structure and material, one on the inner surface of the outer spherical shell and the other on the outer surface of the inner spherical shell. Each friction generator includes a first friction layer arranged on the outer surface of the inner spherical shell, and a forked electrode layer and a second friction layer arranged on the inner surface of the outer spherical shell, which are used to convert mechanical energy into electrical energy.

[0014] Furthermore, the bearings adopt super-lubricating ceramic bearings and the shafts adopt steel shafts.

[0015] Furthermore, the outer spherical shell is made of a lightweight and corrosion-resistant material, such as acrylic; symmetrical semicircular holes are cut at the connecting plane of the two hollow hemispheres of the outer spherical shell to form a complete circular hole for embedding super-lubricating ceramic bearings and steel shafts, and two symmetrical small holes are cut on both sides of the circular hole to facilitate the installation and disassembly of the concentric spherical shell and the lead-out of the wires.

[0016] Furthermore, the inner spherical shell is made of a lightweight and corrosion-resistant material, such as acrylic; a circular hole is cut into the inner spherical shell at the junction of the upper and lower hollow hemispheres, corresponding to the circular hole of the outer spherical shell, for embedding bearings and steel shafts; a swing component is adhered to the arc surface at the bottom of the lower hollow sphere to fix the counterweight.

[0017] Furthermore, the swing component can be 3D printed with photosensitive resin, and the overall shape is a spherical crown that can be completely fitted to the arc surface of the bottom half of the hollow ball in the inner spherical shell. The arc surface of the spherical crown is completely adhered to the arc surface of the bottom half of the hollow ball. A circular groove of a certain area is cut in the center of the plane of the swing component to fix the cylindrical counterweight copper block to lower the center of gravity of the device and facilitate the swing of the device.

[0018] Furthermore, the first friction layer of the triboelectric power generation unit is made of a non-metallic insulating electret material with strong electronegativity. The second friction layer of the triboelectric power generation unit is made of a non-metallic insulating electret material with weak electronegativity. The interdigital electrode layer of the triboelectric power generation unit is made of a metal conductive film or a single-layer conductive material with weak electronegativity.

[0019] Furthermore, the two friction generators of the friction power generation unit are connected in parallel through wires to obtain electrical energy, and a rectifier circuit is used to supply power to the load.

[0020] Furthermore, the interface between the two hollow hemispheres is sealed with hot melt adhesive or polytetrafluoroethylene sealing tape, and then further fixed with waterproof tape.

[0021] The spherical non-contact friction nanogenerator for efficiently collecting low-frequency wave energy, taking the lower half of the spherical shell friction generator as an example, has a working mode of four steps:

[0022] 1) In the initial stage, the electret material of the first friction layer completely overlaps with the copper electrode I. Through pre-friction, the charge accumulates on the electret material until saturation. The first friction layer and the second friction layer generate equal amounts of negative and positive charges on their surfaces, respectively. At the same time, the two groups of interdigitated copper electrodes I and copper electrodes II induce equal amounts of opposite charges, respectively.

[0023] 2) The rotor rotates counterclockwise relative to the stator. The potential difference between the two sets of copper electrodes changes during the rotation, and the generated current flows from copper electrode I to copper electrode II along the external circuit;

[0024] 3) The rotor continues to rotate, and the current continues to flow to copper electrode II until the electret material completely overlaps with copper electrode II, and the positive charge is completely transferred to copper electrode II;

[0025] 4) The rotor rotates further counterclockwise, and the other adjacent electret material of the first friction layer moves toward copper electrode I. At this time, the process is similar to step 2), except that the direction of the current changes from copper electrode II to copper electrode I, until the electret material completely faces copper electrode I. At this time, the positive charge is completely transferred to copper electrode I. At this point, the friction nanogenerator completes one cycle and outputs alternating current; if the rotor rotates clockwise, the same applies; under the periodic triggering of the waves, the rotor rotates in both directions and can continuously output alternating current; the output current is rectified by the rectifier circuit, and then the energy storage element can be charged or small electronic devices can be directly powered.

[0026] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0027] 1. Innovative non-contact design: The present invention proposes a new spherical non-contact friction nanogenerator, which consists of a stator and a rotor, wherein the stator corresponds to the outer shell of the concentric sphere, and the rotor corresponds to the inner shell. This design forms a non-contact friction nanogenerator structure between the copper electrode on the inner surface of the outer shell and the polytetrafluoroethylene (PTFE) film on the outer surface of the inner shell. Through this non-contact structure, the present invention can effectively convert mechanical energy into electrical energy. In particular, it can collect widely distributed, low-frequency, and irregular peak wave energy, and convert it into electrical energy to provide power support for small electronic devices. The low-cost, simple-structured, and stable-performance non-contact TENG provided provides a practical solution for collecting and utilizing irregular wave energy, which has important practical significance and broad application prospects.

[0028] 2. High-efficiency energy output performance: Compared with traditional electromagnetic generators, the spherical non-contact friction nanogenerator described in the present invention has higher output efficiency when collecting low-frequency wave fluctuations. According to theory, its output current is proportional to the frequency of mechanical energy. Therefore, when facing high-entropy and low-frequency wave energy, the performance of the friction nanogenerator is particularly outstanding, and the output efficiency of the friction nanogenerator is much higher than that of traditional electromagnetic generators. This high-efficiency energy output performance gives the present invention a significant advantage in collecting and utilizing wave energy, can greatly increase the output performance, and provide new possibilities for the development and utilization of wave energy.

[0029] 3. Large-scale integration and self-powered system: The present invention can integrate multiple friction power generation units on a large scale according to the specific environment and actual needs, and carry out large-scale blue wave energy collection in an array. This integrated application method not only improves the efficiency of energy collection, but also makes the entire system more stable and reliable. Through large-scale integration, the present invention can form a self-powered system to convert the endless wave energy into electrical energy to power various small electronic devices. For example, it can light up LED lights and provide power support for small devices such as thermometers and hygrometers, thereby achieving energy self-sufficiency.

[0030] 4. Low cost and long life: The non-contact friction nanogenerator made of the copper electrode on the inner surface of the outer spherical shell and the PTFE film on the outer surface of the inner spherical shell is low-cost, simple in structure, and easy to manufacture and promote on a large scale. The non-contact design fundamentally avoids physical contact of the friction material, thereby reducing damage to the friction layer material and reducing energy loss caused by friction. This design not only extends the life of the equipment, but also reduces performance degradation, improves energy conversion efficiency, and makes the entire system more stable and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the 3D structure of the present invention.

[0032] Figure 2 It is a schematic diagram of the cross-sectional structure of the present invention.

[0033] Figure 3 Schematic diagram of the structural shape of the electrode layer and friction layer materials.

[0034] Figure 4 Schematic diagram of the principle of a non-contact friction power generation unit.

[0035] Figure 5 This is a diagram of the electrical output test results of the present invention in a simulated wave environment.

[0036] Figure 6 This is a diagram showing the durability test results of the present invention in a simulated wave environment.

[0037] Figure 7 This is a diagram showing the effect of lighting a commercial LED according to the present invention. DETAILED DESCRIPTION

[0038] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0039] like Figure 1 and 2 As shown, this embodiment is a spherical non-contact friction nanogenerator that efficiently collects low-frequency wave energy. The components include an outer spherical shell 1, an inner spherical shell 2, a swing component 3, a super-lubricating ceramic bearing 4, a stainless steel shaft 5, and a counterweight copper block 6. The friction power generation unit that can convert mechanical energy into electrical energy is a non-contact friction nanogenerator.

[0040] In this embodiment, the inner spherical shell 2 and the outer spherical shell 1 are both formed by connecting two identical hollow hemispheres, and are divided into upper and lower hemisphere shells; the interface between the two hollow hemispheres is sealed with hot melt adhesive or polytetrafluoroethylene sealing tape, and then further fixed with waterproof tape to prevent water from entering the interior of the sphere.

[0041] The friction power generation unit encapsulated in the outer spherical shell 1 includes two friction generators with completely identical structures and materials, the upper and lower parts of the inner surface of the outer spherical shell 1 and the outer surface of the inner spherical shell 2. Each friction generator includes a first friction layer 7 located on the outer surface of the inner spherical shell, and an interdigitated electrode layer 8 and a second friction layer 9 located on the inner surface of the outer spherical shell.

[0042] The upper and lower hemispheres of the outer spherical shell 1 are made of acrylic material. Symmetrical semicircular holes are cut at the connecting plane of the two hollow hemispheres to form a complete circular hole, and the same drilling process is performed at the symmetrical position on the back to embed the super-lubricating ceramic bearing 4 and the stainless steel shaft 5.

[0043] The upper and lower hemispheres of the inner spherical shell 2 are made of acrylic material. A semicircular hole is cut out at the plane connection of the two hollow hemispheres to form a complete circular hole, which corresponds to the circular hole of the outer spherical shell 1 and is used to embed the super-lubricating ceramic bearing 4 and the stainless steel shaft 5. The super-lubricating ceramic bearing 4 and the stainless steel shaft 5 can be used to assemble the inner and outer spherical shells to form a coaxial spherical shell; a swing component is adhered to the arc surface at the bottom of the lower half of the hollow ball of the inner spherical shell 2 to fix the counterweight.

[0044] The swing component 3 is manufactured by photosensitive resin 3D printing technology, and is in the shape of a spherical cap that can be completely attached to the arc surface of the bottom half of the hollow ball in the inner spherical shell. In this embodiment, the swing component 3 is a spherical cap cut from a sphere. The arc surface of the spherical cap is completely adhered to the arc surface of the bottom half of the hollow ball. A circular groove of a certain area is cut in the center of the plane of the swing component 3 to fix the cylindrical counterweight copper block 6.

[0045] The first friction layer 7 of the friction power generation unit is made of a non-metallic insulating electret material with strong electronegativity; specifically, polytetrafluoroethylene (PTFE) is used in this embodiment with a thickness of 50 μm. Figure 3 The blade-shaped PTFE strips formed by the arc edges shown have a short side of 5 mm and a long side of 300 mm, and are arranged on the outer surface of the inner spherical shell at equal intervals with a spacing of 7 mm.

[0046] The second friction layer of the friction power generation unit is made of non-metallic insulating electret material with weak electronegativity; specifically, nylon is used in this embodiment with a thickness of 50 μm, which is pasted to the outermost layer of the inner surface of the outer spherical shell and covers the interdigital electrodes of the friction power generation unit.

[0047] The interdigitated electrode layer of the friction power generation unit is made of a metal conductive film or a single-layer conductive material with weak electronegativity; specifically, the flexible interdigitated copper foil electrode manufactured by commercial PCB technology in this embodiment is 35 μm thick and has a 25 μm thick polyimide (PI) backing 10, which is convenient for pasting on the inner surface of the outer spherical shell; the copper foil electrode is similar to the PTFE strip, and is in the shape of a blade composed of arc edges, with a short side of 5 mm and a long side of 300 mm, and is arranged on the inner surface of the outer spherical shell with a spacing of 1 mm. The copper foil electrodes are divided into two groups (such as Figure 2 Each group of copper foil electrodes is connected in parallel to form interdigital electrodes. The nylon film covers the interdigital electrode layer to prevent breakdown discharge and increase output.

[0048] The friction power generation unit includes two friction generators in the upper and lower parts of the hollow spherical shell, which are connected in parallel through wires to obtain electrical energy and use a rectifier circuit to supply power to the load.

[0049] The spherical non-contact friction nanogenerator, taking the lower half of the spherical shell friction generator as an example, has a working mode of four steps:

[0050] 1) Initial stage: The electret material (PTFE film in this embodiment, as the first friction layer) and the copper electrode I (part of the interdigital electrode) are completely overlapped. Through pre-rubbing or electron injection, the charge is continuously accumulated on the electret material until it reaches a saturation state. At this time, the surface of the first friction layer (PTFE film) carries an equal amount of negative charge, while the surface of the second friction layer (nylon film) carries an equal amount of positive charge; at the same time, due to the electrostatic induction effect, the two groups of interdigital electrodes (copper electrode I and copper electrode II) respectively induce equal but opposite polarity charges;

[0051] 2) Counterclockwise rotation stage: When the rotor rotates counterclockwise relative to the stator, the potential difference between the two sets of interdigitated electrodes (copper electrode I and copper electrode II) changes during the rotation process. Due to the uneven distribution of charges on the electret material, a potential difference is generated during the rotation process, thereby driving electrons to flow in the external circuit. Specifically, the current flows out from the negatively charged copper electrode I (which is in contact with the electret material at this time) and flows along the external circuit to the copper electrode II with positive charge induction.

[0052] 3) Complete overlap stage: As the rotor continues to rotate, the current continues to flow to copper electrode II until the electret material and copper electrode II completely overlap. At this time, the positive charge on the electret material is completely transferred to copper electrode II; and copper electrode I returns to a neutral state due to the loss of negative charge.

[0053] 4) Another piece of electret material moves toward electrode I: The rotor rotates further counterclockwise. At this time, another piece of electret material moves toward copper electrode I. This is similar to step 2), except that the direction of the current changes from copper electrode II to copper electrode I. Since the charge distribution on the electret material changes again, the positive charge on copper electrode II begins to decrease, while copper electrode I begins to induce negative charge. Therefore, the direction of the current changes, flowing from copper electrode II to copper electrode I. This process continues until another piece of electret material is completely facing copper electrode I. At this point, TENG completes a full cycle and outputs alternating current. The detailed process is as follows. Figure 4 shown.

[0054] It should be noted that if the rotor rotates clockwise, the above process is also applicable, but the current direction will be reversed. That is, the current flows from copper electrode II to copper electrode I (in the initial stage), and then flows in the opposite direction as the rotor rotates.

[0055] Under the periodic triggering of the waves, the rotor rotates in both directions, thereby continuously outputting alternating current. In order to use this alternating current to charge energy storage components or directly power small electronic devices, a rectifier circuit is required to rectify the output current. The rectifier circuit can convert alternating current into direct current, thereby meeting the power supply needs of various electronic devices.

[0056] In this embodiment, the first friction layer and the second friction layer are PTFE film and nylon film respectively, and these two materials have good electronegativity difference and wear resistance. The two groups of interdigitated electrodes (copper electrode I and copper electrode II) each contain 25 copper electrodes. These copper electrodes are arranged on the inner surface of the outer spherical shell through a precise manufacturing process and form an effective friction power generation unit with the electret material.

[0057] In order to verify the effectiveness of the present invention, the following examples are described:

[0058] 1. Wave simulation system and electrical performance test

[0059] A wave simulation system was successfully built using a water tank and a wave pump group to simulate a real low-frequency water wave vibration environment. Under the simulated wave conditions, the electrical performance of the present invention was tested.

[0060] Depend on Figure 5 The electrical performance test data shown in the figure show that the spherical non-contact TENG in this embodiment shows excellent performance in the simulated wave system. The open circuit voltage of TENG in the simulated wave system is as high as 130.6 V and the short circuit current is 16.3 μA with low-frequency water wave vibration. These data fully prove that the present invention can effectively generate electrical energy under low-frequency water wave vibration conditions.

[0061] exist Figure 5In the figure, the left picture is a voltage chart, with the horizontal and vertical axes representing time (s) and voltage (V) respectively; the right picture is a current chart, with the horizontal and vertical axes representing time (s) and current (A) respectively.

[0062] 2. Durability test

[0063] Under the above experimental environment, the durability test of the present invention was carried out for 5 consecutive hours. Figure 6 The durability test data shown clearly shows that the current output of the present invention does not show any signs of attenuation during 5 hours of continuous operation. This result not only verifies the excellent durability of the present invention, but also shows that the present invention can stably provide electrical energy for a long time in practical applications.

[0064] 3. Commercial LED lighting experiment

[0065] In order to further verify the ability of the present invention to power small electronic devices, a commercial LED lighting experiment was conducted. Figure 7 The effect diagram of TENG lighting up commercial LEDs. In the simulation system, as the waves are triggered, the spherical non-contact TENG described in this embodiment can light up more than 40 LEDs in the simulation system as the waves are triggered. And after a month of long-term working test, the present invention can still stably power these LEDs. This result proves the ability of the present invention to power small electronic devices, as well as its excellent durability, and the present invention has broad potential in practical applications.

[0066] The present invention adopts a spherical structure, with the inner spherical shell as the rotor, which rotates bidirectionally under the periodic triggering of water waves to convert mechanical energy into electrical energy. Through the air gap between the inner and outer spherical shells and the super-lubricating ceramic bearings, the inner and outer spherical shells constitute a non-contact TENG, which has the advantages of simple structural design, convenient preparation, high energy conversion rate, stable performance, long device life, easy large-scale manufacturing, and array integrated application. After experimental verification, the present invention can effectively convert widely distributed, low-frequency, high-entropy, and irregular peak wave energy into electrical energy, which can directly power small electronic devices after rectification, such as lighting LEDs and charging capacitors.

[0067] The structure and shape of the present invention are not limited to those described in this embodiment. In complex environments, the device can be modified to a multi-layer spherical structure to obtain more friction power generation units and a larger electrode area, thereby improving space utilization and obtaining higher output performance. The number of devices can also be increased to form a power generation array to effectively increase the output current.

[0068] The present invention provides a spherical non-contact TENG for efficiently collecting low-frequency wave energy. The non-contact TENG is formed by the air gap between the stator and the rotor, which effectively avoids the physical contact of the friction material, reduces the damage to the friction layer material, and reduces the energy loss caused by friction. It not only improves the energy conversion rate, but also improves the durability of the material and extends the life of the device. The output performance can be controlled by adjusting the device structural parameters such as the air gap distance, the inner and outer spherical shell diameters, etc., and the wave energy can be efficiently collected and the AC power can be output. Combined with a rectifier to convert the AC power into DC power, it can directly power small electronic devices, and has broad application prospects in the efficient realization of large-scale wave energy collection.

[0069] The above embodiments are only preferred embodiments of the present invention and cannot be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A spherical non-contact friction nanogenerator for efficiently collecting low-frequency wave energy, characterized in that It includes an outer spherical shell, an inner spherical shell, a swinging assembly, a bearing, a shaft, a counterweight, and a friction power generation unit, wherein the friction power generation unit for converting mechanical energy into electrical energy is non-contact; The outer spherical shell, composed of two identical hollow hemispheres, serves as the stator; the interface between the two hollow hemispheres is sealed and fixed to prevent water from entering the interior of the sphere; The inner spherical shell is also composed of two identical hollow hemispheres. It serves as a rotor and is arranged inside the outer spherical shell and can rotate freely inside the outer spherical shell. The interface between the two hollow hemispheres is sealed and fixed to prevent water from entering the interior of the sphere. A swing assembly is fixed to the bottom of the inner spherical shell and is used to increase the swing effect of the inner spherical shell under the action of waves; Counterweight , which is arranged on the swing assembly and is used to lower the center of gravity of the entire device; The bearing and the shaft are arranged between the outer spherical shell and the inner spherical shell to ensure that the inner spherical shell can rotate smoothly inside the outer spherical shell; The friction power generation unit includes two friction generators with exactly the same structure and material, one on the inner surface of the outer spherical shell and the other on the outer surface of the inner spherical shell. Each friction generator includes a first friction layer arranged on the outer surface of the inner spherical shell, and a forked electrode layer and a second friction layer arranged on the inner surface of the outer spherical shell, which are used to convert mechanical energy into electrical energy.

2. A spherical non-contact friction nanogenerator for efficiently collecting low-frequency wave energy as claimed in claim 1, characterized in that The bearings are super-lubricating ceramic bearings, and the shafts are steel shafts.

3. A spherical non-contact friction nanogenerator for efficiently collecting low-frequency wave energy as claimed in claim 1, characterized in that The outer spherical shell is made of acrylic material; symmetrical semicircular holes are cut at the connecting plane of the two hollow hemispheres of the outer spherical shell to form a complete circular hole for embedding super-lubricating ceramic bearings and steel shafts, and two symmetrical small holes are cut on both sides of the circular hole to facilitate the installation and disassembly of the concentric spherical shell and the lead-out of the wires.

4. A spherical non-contact friction nanogenerator for efficiently collecting low-frequency wave energy as claimed in claim 1, characterized in that The inner spherical shell is made of acrylic material; a circular hole is cut out at the junction of the upper and lower hollow hemispheres of the inner spherical shell, corresponding to the circular hole of the outer spherical shell, for embedding bearings and steel shafts; a swing component is adhered to the arc surface at the bottom of the lower hollow sphere to fix the counterweight block.

5. A spherical non-contact friction nanogenerator for efficiently collecting low-frequency wave energy as claimed in claim 1, characterized in that The swing component is made of photosensitive resin 3D printing, and the overall shape is a spherical crown that can completely fit the arc surface of the bottom half of the hollow ball in the inner spherical shell; the arc surface of the spherical crown shape is completely adhered to the arc surface of the bottom half of the hollow ball in the lower half, and a circular groove of a certain area is cut in the center of the plane of the swing component to fix the cylindrical counterweight copper block to lower the center of gravity of the device and facilitate the swing of the device.

6. A spherical non-contact friction nanogenerator for efficiently collecting low-frequency wave energy as claimed in claim 1, characterized in that The first friction layer of the friction power generation unit is made of a non-metallic insulating electret material with strong electronegativity; the second friction layer of the friction power generation unit is made of a non-metallic insulating electret material with weak electronegativity; and the interdigitated electrode layer of the friction power generation unit is made of a metal conductive film or a single layer conductive material with weak electronegativity.

7. A spherical non-contact friction nanogenerator for efficiently collecting low-frequency wave energy as claimed in claim 1, characterized in that The two friction generators of the friction power generation unit are connected in parallel through wires to obtain electrical energy, and a rectifier circuit is used to supply power to the load.

8. A spherical non-contact friction nanogenerator for efficiently collecting low-frequency wave energy as claimed in claim 1, characterized in that The interface between the two hollow hemispheres is sealed with hot melt adhesive or polytetrafluoroethylene sealing tape, and then further fixed with waterproof tape.

9. A spherical non-contact friction nanogenerator for efficiently collecting low-frequency wave energy as claimed in claim 1, characterized in that Its working mode is: 1) In the initial stage, the electret material of the first friction layer completely overlaps with the copper electrode I. Through pre-friction, the charge accumulates on the electret material until saturation. The first friction layer and the second friction layer generate equal amounts of negative and positive charges on their surfaces, respectively. At the same time, the two groups of interdigitated copper electrodes I and copper electrodes II induce equal amounts of opposite charges, respectively. 2) The rotor rotates counterclockwise relative to the stator. The potential difference between the two sets of copper electrodes changes during the rotation, and the generated current flows from copper electrode I to copper electrode II along the external circuit; 3) The rotor continues to rotate, and the current continues to flow to copper electrode II until the electret material completely overlaps with copper electrode II, and the positive charge is completely transferred to copper electrode II; 4) The rotor rotates further counterclockwise, and the other adjacent electret material of the first friction layer moves toward copper electrode I. At this time, the process is similar to step 2), except that the direction of the current changes from copper electrode II to copper electrode I, until the electret material completely faces copper electrode I. At this time, the positive charge is completely transferred to copper electrode I. At this point, the friction nanogenerator completes one cycle and outputs alternating current; if the rotor rotates clockwise, the same applies; under the periodic triggering of the waves, the rotor rotates in both directions and continuously outputs alternating current; the output current is rectified by the rectifier circuit, and then the energy storage element can be charged or small electronic devices can be directly powered.

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