A roll-tape friction nanogenerator based on interfacial static friction

Abstract

The application discloses a rolling band type friction nanogenerator based on interface static friction force, which comprises an independent layer and a stator, the independent layer rolls on the stator to generate electric charges, and the stator outputs electric energy; the independent layer is a conductive closed rolling band. The application rolls on the insulating layer of the stator to generate electric charges by designing the conductive closed rolling band, avoids the existence of sliding friction, has very small friction loss of materials, reduces the heat loss of the friction process in the working process, reduces useless work, improves the energy conversion efficiency, and thus improves the durability and output performance.

Description

Technical Field

[0001] This invention relates to the field of generator technology, and in particular to a roller-type triboelectric nanogenerator based on interfacial static friction. Background Technology

[0002] Triboelectric nanogenerators with sliding modes, including planar sliding and independent layer modes, are widely used to harvest various forms of high-entropy mechanical energy due to their high mechanical energy conversion efficiency and easy encapsulation. However, the heat and material wear caused by sliding friction in planar sliding / rotation limit the stability and durability of triboelectric nanogenerators.

[0003] Chinese invention patent CN105790631A discloses a rolling triboelectric nanogenerator, which reduces friction loss through rolling friction, thereby improving the generator's stability and durability. However, this method requires changing the original surface contact between different friction layers into line contact or point contact. While reducing material friction loss, the generator's output performance is also significantly weakened. Therefore, it is essential to propose a strategy that can simultaneously improve electrical output performance and durability. Summary of the Invention

[0004] To address the issues of low durability and output performance in existing triboelectric nanogenerators, this invention proposes a roller-type triboelectric nanogenerator based on interfacial static friction. By designing a conductive closed rolling belt, it generates charges through rolling contact with the insulating layer of the stator, avoiding sliding friction and minimizing material friction loss. Simultaneously, the heat loss during operation is reduced, and the reduction in wasted work translates to improved energy conversion efficiency, thereby enhancing durability and output performance.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A rolling triboelectric nanogenerator based on interfacial static friction includes an independent layer and a stator. The independent layer rolls on the stator to generate charge, and the stator outputs electrical energy. The independent layer is a conductive closed rolling belt.

[0007] Preferably, the conductive closed rolling belt has a thickness of 1-5mm, a width of not less than 20mm, and a height of not less than 5mm in the middle.

[0008] Furthermore, the conductive closed rolling belt has a thickness of 2mm, a width of 40mm, and a height of 10mm in the middle.

[0009] Preferably, the conductive closed rolling belt has n conductive rollers in the middle, where n ≥ 2 and is a positive integer; the conductive rollers are cylindrical in shape, with a length greater than 20 mm, and their outer diameter is the same as the middle height of the conductive closed rolling belt.

[0010] Furthermore, the conductive roller is cylindrical in shape, with a length of 40mm, an outer diameter of 10mm, and an inner diameter of 6mm.

[0011] Preferably, the material of the conductive closed rolling belt is a mixture of insulating material and conductive filler.

[0012] Preferably, the weight ratio of the insulating material to the conductive filler is not less than 10:1.

[0013] Preferably, the surface of the conductive closed rolling strip has a microstructure at the micrometer level.

[0014] Preferably, the stator includes an insulating layer, an electrode pair, and a substrate; the insulating layer is disposed on the upper surface of the electrode pair, and the lower surface of the electrode pair is fixed on the substrate.

[0015] Preferably, the insulating layer is a fluorinated ethylene propylene film; and the area of ​​the insulating layer is greater than the total area of ​​the electrode pair.

[0016] Preferably, it further includes a self-excitation circuit, the input terminal of which is connected to the electrode pair, and the output terminal of which is connected to the independent layer.

[0017] Preferably, it also includes a power management circuit for stepping down and rectifying the electrical energy output by the generator and outputting it to the load.

[0018] In summary, by adopting the above technical solution, the present invention has at least the following beneficial effects compared with the prior art:

[0019] The present invention discloses a roller-type triboelectric nanogenerator based on interfacial static friction, which has a simple structure and significant effects. Since there is no relative sliding when the independent layer and the insulating layer are in contact, the frictional loss of the materials is minimal. Simultaneously, by avoiding sliding friction, heat loss during operation is reduced, and the reduction of wasted work translates to improved energy conversion efficiency. Furthermore, thanks to the electron storage capability of the low-impedance silicone rubber film, charge can be rapidly accumulated in the self-excited circuit, thereby increasing the charge density on the surface of the independent layer and improving durability and output performance. Attached image description:

[0020] Figure 1 This is a schematic diagram of a roller-type triboelectric nanogenerator based on interfacial static friction according to an exemplary embodiment of the present invention.

[0021] Figure 2 a is a schematic diagram illustrating the effect of different weight ratios of silicone and carbon black on resistance according to an exemplary embodiment of the present invention; Figure 2 b is a schematic diagram showing the effect of different weight ratios of silica gel and carbon black on the output charge; Figure 2 c is a schematic diagram showing the effect of different weight ratios of silica gel and carbon black on the output voltage.

[0022] Figure 3 a is a schematic diagram comparing the number of rollers with the transferred charge and voltage according to an exemplary embodiment of the present invention; Figure 3 b is a schematic diagram illustrating the effect of different surface roughness of independent layers on charge and voltage according to an exemplary embodiment of the present invention.

[0023] Figure 4 a is a schematic diagram of charge distribution when an independent layer is located at one end of an insulating layer according to an exemplary embodiment of the present invention; Figure 4 b is a schematic diagram of charge distribution when an independent layer rolls on an insulating layer according to an exemplary embodiment of the present invention; Figure 4 c is a schematic diagram of charge distribution when the independent layer is located at the other end of the insulating layer according to an exemplary embodiment of the present invention.

[0024] Figure 5 This is a schematic diagram comparing the output performance of different types of generators according to an exemplary embodiment of the present invention.

[0025] Figure 6 This is a schematic diagram comparing the stability of RB TENG and FS TENG according to an exemplary embodiment of the present invention.

[0026] Figure 7 This is a schematic diagram comparing the durability of RB-TENG and FS TENG according to an exemplary embodiment of the present invention.

[0027] Figure 8 This is a schematic diagram illustrating the temperature changes on the surface of the insulating layer when the RB TENG and FS TENG are continuously operating according to an exemplary embodiment of the present invention.

[0028] Figure 9 This is a schematic diagram of a self-excitation circuit according to an exemplary embodiment of the present invention.

[0029] Figure 10 This is a schematic diagram of a power management circuit according to an exemplary embodiment of the present invention.

[0030] Figure 11 This is a schematic diagram of the RB TENG with power management circuitry outputting electrical energy according to an exemplary embodiment of the present invention. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to embodiments and specific implementation methods. However, this should not be construed as limiting the scope of the above-described subject matter of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0032] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0033] like Figure 1 As shown, the present invention provides a rolling triboelectric nanogenerator based on interfacial static friction, comprising an independent layer 1 and a stator. The independent layer 1 rolls on the stator to generate charge, and the stator outputs electrical energy.

[0034] In this embodiment, the independent layer 1 is a conductive closed rolling strip, shaped similarly to a tank track. The conductive closed rolling strip has a thickness of 1-5 mm, a width of not less than 20 mm, and a center height of not less than 5 mm. Preferably, the conductive closed rolling strip has a thickness of 2 mm, a width of 40 mm, and a center height of 10 mm.

[0035] The conductive closed rolling belt has n conductive rollers 11 (which can be made of metal, such as copper or aluminum) in the middle. The purpose of the conductive rollers is to increase the tightness of the contact between the rolling belt and the stator surface, where n is a positive integer. The conductive rollers are cylindrical in shape, with a length greater than 20 mm and an outer diameter of not less than 5 mm. Preferably, the conductive rollers are cylindrical in shape, with a length of 40 mm, an outer diameter of 10 mm, and an inner diameter of 6 mm.

[0036] In this embodiment, the conductive closed rolling belt is made of a flexible and stretchable composite conductive material, which is composed of an insulating material (such as silicone, PDMS, PVDF, ecoflex, etc.) and a conductive filler material (such as metal nanoparticles, conductive nanowires, carbon nanofibers, carbon black, etc.). The conductive filler material is filled in the insulating material to increase the conductivity of the independent layer and improve the output performance.

[0037] In this embodiment, the insulating material is preferably silicone, and the conductive filler material is preferably carbon black. The preparation method is as follows:

[0038] Liquid silica gel solution (HC9010, Shore hardness: 10, dynamic viscosity: 3000 cP) was purchased from Shenzhen Hengchang Organosilicon Co., Ltd., China, and divided into two groups, A and B. A measured amount of conductive carbon black particles (TIMCAL SUPER P Li) was gradually added to groups A and B respectively. After stirring at 200 rads / min for 25 minutes, the mixture was placed in a negative pressure environment to remove air bubbles. Groups A and B were then mixed in equal proportions (separate mixing to improve uniformity) and stirred at 100 rads / min for 20 minutes. The mixture was then introduced into molds with different internal surface textures (PMMA, A4 paper, and sandpaper, with different roughnesses), and films were prepared by scraping. After 12 hours at room temperature, the two ends of the fully cured film were connected with silicone sealant (J-527S) to form a conductive closed rolling strip. This facilitates the preparation of conductive closed rolling strips with different external surface morphologies and allows for testing of their impact on output. Alternatively, a one-piece molding method can also be used.

[0039] In this embodiment, as Figure 2 As shown, different weight ratios of silica gel and carbon black have a significant impact on generator performance. Figure 2 (a) The weight ratios of silica gel and carbon black are 50:1, 30:1, 20:1 and 10:1, respectively. As the weight ratio increases, the resistance gradually decreases from more than 304 kΩ / mm to close to 17 Ω / mm. Figure 2 (b) The weight ratios of silica gel and carbon black are pure silica gel, 50:1, 30:1, 20:1 and 10:1, respectively. As the weight ratio increases, the output charge gradually increases. Figure 2 (c) The weight ratios of silica gel and carbon black are pure silica gel, 50:1, 30:1, 20:1 and 10:1, respectively. As the weight ratio increases, the output voltage gradually increases.

[0040] Therefore, in summary, the weight ratio of silicone to carbon black should be no less than 10:1 to ensure that the resistivity of the conductive closed rolling belt is no higher than 100Ω / mm, so as to ensure that the independent layers can transfer and accumulate charge.

[0041] In this embodiment, as Figure 3 As shown, the tightness between the independent layer and the stator contact surface or the surface morphology of the independent layer also affects the output power. Figure 3 In (a), by increasing the number of rollers in the conductive closed rolling belt to improve the tightness between the independent layer and the stator contact surface (the more rollers there are, the greater the weight, and the greater the pressure on the stator contact surface, i.e., the higher the tightness), it can be seen that as the number of rollers increases, the transferred charge and voltage gradually increase. Figure 3In (b), the effect of conductive closed rolling strips with different roughness (i < iii < ii < iv < v < vi) on charge and voltage is shown. As the surface roughness increases, the transferred charge and voltage first increase and then decrease, reaching a maximum at iv (corresponding to 1000 grit sandpaper). The reason for this phenomenon is that the microstructure on the surface of the conductive closed rolling strip increases the specific surface area, which can effectively improve the output performance. However, when the surface structure is too rough, the gaps between the interfaces will affect the contact efficiency, resulting in lower output.

[0042] In this embodiment, the stator includes an insulating layer 2, an electrode pair 3, and a substrate 4.

[0043] The insulating layer 2 is made of FEP (fluorinated ethylene propylene) film; the two copper electrodes (50 mm long and 30 mm wide) of the electrode pair 3 are deposited on the substrate 4 (acrylic substrate) by physical vapor deposition. The area of ​​the insulating layer 2 is larger than the total area of ​​the electrode pair 3. The two sets of metal electrodes in the electrode pair 3 are complementary structures and may contain multiple repeating unit structures.

[0044] In this embodiment, the working principle of a roller-type triboelectric nanogenerator based on interfacial static friction is as follows:

[0045] By rolling the independent layer while maintaining continuous contact at one end of the insulating layer and separation at the other end, static friction (no relative sliding) between the independent layer and the insulating layer is achieved, which can effectively avoid the impact of sliding friction on electrical output performance.

[0046] like Figure 4 As shown in Figure a, under short-circuit conditions, when one end of the independent layer 1 and the insulating layer 2 are in contact, due to the different abilities of the two to attract electrons, electrons transfer from the surface of the independent layer 1 to the insulating layer 2, and the electrode at the other end becomes positively charged; as shown in Figure a. Figure 4 As shown in b, when the independent layer 1 rolls from one end to the other on the insulating layer 2, positive charges drive electrons to flow from one electrode to the other; as Figure 4 As shown in Figure c, when the independent layer 1 rolls to the other end of the insulating layer 2, the charge of the electrode at the other end is transferred to the other electrode.

[0047] like Figure 5 The figure shows a comparison of the output performance of different types of generators. (1) represents the rolling R-TENG with low material loss, (2) represents the sliding FS TENG with high output performance and high material loss, and (3) represents the rolling belt generator (RB-TENG) of the present invention. It can be seen that the transferred charge of RB-TENG and contact FS TENG is very close, both about 3.8 times that of R-TENG, that is, the generator (RB-TENG) of the present invention has higher output performance.

[0048] The stability and durability of TENGs are of utmost importance for their practical applications. They determine whether a TENG can continuously provide sufficient power to electronic devices for extended periods.

[0049] like Figure 6 As shown, the stability comparison chart of RB-TENG and FS TENG shows that under normal charge output and the same pressure, the generator (RB-TENG) of this invention maintains a stability of over 98% after about 4,000,000 cycles due to static contact, while the stability of FS TENG drops to 70% after 3,000 soul rings.

[0050] like Figure 7 As shown in the figure, the durability comparison chart of RB-TENG and FS TENG shows that after 19 days of continuous operation (2.5Hz), the average mass of the conductive closed rolling belt of RB-TENG decreased from 5.0640g to 5.0506g, with a loss of 6.418μg / g per 10,000 cycles. In contrast, in FS mode, the mass of the silicone mixture decreased from 5.2252g to 5.2127g after 34,500 cycles, with a loss of 649μg / g per 10,000 cycles. This means that the material wear of FS-TENG is almost 100 times that of RB-TENG.

[0051] like Figure 8 The figure shows the temperature changes on the surface of the insulation layer of RB TENG and FS TENG during continuous operation. It can be seen that the temperatures of FSTENG during continuous operation for 0s, 150s, 225s, and 300s are 22.2℃, 29.7℃, 34.9℃, and 41.5℃, respectively; while the temperatures of RB-TENG during continuous operation for 0s, 150s, 225s, and 300s are 20.4℃, 21.7℃, 24.1℃, and 25.5℃, respectively. This means that compared to FS TENG, the heat generation of RB-TENG is negligible, indicating that the energy conversion efficiency is effectively improved due to the conversion of less mechanical energy into heat energy.

[0052] In this embodiment, as Figure 9 As shown, to further improve the electrical performance of the RB-TENG, a self-excited circuit 5 is used to increase the surface charge density of the independent layer 1. After several cycles, the voltage across the capacitor in the self-excited circuit 5 cannot change abruptly, and the diode only allows current to flow in one direction. This means that positive charge will gradually be injected into the independent layer 1 over time, and the output will be increased due to the electrostatic induction effect, ultimately forming a self-excited system.

[0053] After using the self-excited circuit 5, under conditions of 60% humidity and 0.5Hz operating frequency, the generator output charge increased from 128nC to 210nC, and the current increased from 0.24μA to 0.54μA. After the output stabilized, the 454 green light-emitting diodes (LEDs) connected in series lit up.

[0054] In this embodiment, the self-excited circuit 5 effectively improves the electrical performance of the RB-TENG, but does not change the high-voltage and low-current output characteristics. With or without charge excitation, the optimal external load for maximum output power or energy cannot exceed 100MΩ, which greatly limits the practical application of the RB-TENG in electronic devices. Therefore, this invention employs a power management circuit (PMC) to enhance its ability as an ultra-high output current source to eliminate mechanical energy.

[0055] like Figure 10 As shown, the power management circuit includes a rectifier circuit and a step-down circuit. The electrical energy output from the generator after passing through the self-excited circuit 5 is first rectified by the rectifier circuit and stored in the front-end capacitor C1. The voltage across C1 increases with energy accumulation. Then, when the voltage exceeds the threshold set by the threshold switch in the step-down circuit, the switch conducts, and the energy flows to the back-end capacitor C2, and then to the external load. Finally, as... Figure 11 As shown, the RB-TENG's maximum output short-circuit current peak reaches 27mA, while the transferred charge per cycle reaches 7.4μC. Comparing the charging speed of the RB-TENG for a 100μF capacitor with and without PMC, it can be found that after power management, the time for the voltage to rise from 0 to 1.5V at 1Hz is 23.3s, which is much shorter than the time without PMC (charging to 1V in 222 seconds). Simultaneously, a maximum peak power of 339mW is achieved when the external load reaches 3kΩ.

[0056] In this embodiment, a 1.33mF commercial electrolytic capacitor is charged to 2V via an RB-TENG (operating frequency 2Hz) before driving the electronic equipment. When the temperature and humidity monitor starts working, there is a voltage drop of approximately 0.25V. When the voltage drops to approximately 1.6V, the TENG restarts its energy conversion, stabilizing the voltage at the normal operating level. These results demonstrate the potential of the RB-TENG in practical applications.

[0057] In this embodiment, the rolling belt mode can be further divided into a rotation mode and a drum mode, which are used to collect micro-wind energy and water energy in the natural environment.

[0058] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of the present invention.

Claims

1. A roll-tape friction nanogenerator based on interfacial static friction, characterized in that, The independent layer and the stator are in surface contact, the independent layer rolls on the stator to generate electric charge, and the stator outputs electric energy; the independent layer is an electrically conductive closed rolling belt; the stator comprises an insulating layer, an electrode pair and a base; The insulating layer is arranged on the upper surface of the electrode pair, and the lower surface of the electrode pair is fixed on the base; the electrically conductive closed rolling belt is provided with n electrically conductive rollers in the middle, n is greater than or equal to 2 and is a positive integer; the electrically conductive roller is in the shape of a cylinder, the length is greater than 20 mm, and the outer diameter is the same as the middle height of the electrically conductive closed rolling belt; the static friction between the independent layer and the insulating layer is realized by rolling the independent layer by continuously contacting one end of the insulating layer and separating the other end.

2. The triboelectric nanogenerator based on interfacial static friction according to claim 1, wherein, The thickness of the electrically conductive closed rolling belt is 1-5 mm, the width is not less than 20 mm, and the middle height is not less than 5 mm.

3. The triboelectric nanogenerator based on interfacial static friction force of claim 1, wherein, The material of the electrically conductive closed rolling belt is a mixture of an insulating material and an electrically conductive filler.

4. The triboelectric nanogenerator based on interfacial static friction of claim 3, wherein, The weight ratio of the insulating material to the electrically conductive filler is not less than 10:

1.

5. The triboelectric nanogenerator based on interfacial static friction according to claim 1, wherein, The surface of the electrically conductive closed rolling belt has a micron-level microstructure.

6. The triboelectric nanogenerator based on interfacial static friction of claim 1, wherein, The insulating layer is made of fluorinated ethylene propylene film, and the area of the insulating layer is greater than the total area of the electrode pair.

7. The triboelectric nanogenerator based on interfacial static friction of claim 1, wherein, The self-excitation circuit is further provided, the input end of the self-excitation circuit is connected with the electrode pair, and the output end of the self-excitation circuit is connected with the independent layer.

8. The triboelectric nanogenerator based on interfacial static friction of claim 1, wherein, The power management circuit is further provided, which is used for step-down rectification of the electric energy output by the generator and output to the load.

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