| Energy is the foundation of the in-depth advancement of the industrial revolution and rapid economic and social development.Where to obtain and how to obtain energy has become an issue closely related to everyone,and it is also one of the most important research topics for scientists.In the past two hundred years,traditional fossil energy(coal,oil,natural gas,etc.)has played an inestimable role as the world’s most important energy consumption.However,the non-renewability of fossil energy and a series of ecological pollution problems have forced humans to seek Renewable clean energy to achieve sustainable and circular development.At the same time,with the continuous development of the Internet of Things,it is no longer practical to use batteries to power ubiquitous sensors.The development of new energy harvesting technologies has become one of the most effective methods.Among the various renewable energy sources in nature,such as solar energy,mechanical energy,tidal energy,etc.,wind energy,which is widely distributed and has huge reserves,is one of the most attractive energy sources.So far,the most important way to collect wind energy is to convert wind energy into electrical energy using traditional wind turbines based on electromagnetic induction mechanisms.However,the shortcomings of traditional wind turbines such as complicated structure and high manufacturing cost severely limit its wide application.Therefore,it is becoming more and more urgent to develop wind energy collection technologies that are lower in cost,easier to maintain,and more efficient in ordinary environments.The triboelectric nanogenerator(TENG)is a device that converts mechanical energy into electrical energy based on the coupling of frictional electrification and electrostatic induction.It has the advantages of low cost,strong structural flexibility,rich material selection,and high output under low-frequency conditions.It is widely used in self-driving Sensing,environmental energy,etc.It can be seen that TENG has unique advantages in collecting low-frequency mechanical energy(such as human movement,wind energy,wave energy,etc.),and will also provide a new power supply method for smart and wearable electronic products.This dissertation takes the friction nanogenerator technology as the starting point and the high-efficiency collection of low-speed wind energy as the fundamental purpose.The research and design of the friction nanogenerator in the contact separation mode provides a novel and effective method for large-scale collection of breeze energy near the ground.The main research work is as follows:(1)An ultra-durable windmill-like hybrid nanogenerator(W-HNG)has been designed and manufactured to collect widely distributed near-ground breeze energy.WHNG consists of two parts: four triboelectric nanogenerator(TENG)units and four electromagnetic generator(EMG)units.The device creatively introduces a spring steel sheet to act as a TENG electrode,and can also store elastic potential energy and convert it into kinetic energy for the movement of the tribo-layers,thereby improving the contact strength between the friction materials to obtain a larger current and transfer charge.In order to optimize the structural parameters of the device,the electrical output of the spring steel sheet under different parameters was systematically tested,and the output performance of the TENG unit and the EMG unit were tested under different wind speed conditions.The experimental results show that when the wind speed is 1.8 m/s～4.8 m/s,the output voltage of TENG increases from 860 V to 1150 V,and the short-circuit current increases from 6.8 μA to 8.5 μA.When the external load is 100 MΩ,the maximum output power reaches 0.95 m W;when the external load is 20 Ω,the maximum output power of EMG can reach 3.7 m W.After power management,W-HNG can charge a 10 μF commercial capacitor to 2 V within 8 s,and can also be used to power electronic devices,including lighting LED lights and driving digital watches.W-HNG can also be installed near the ground to form a collection array,which is expected to realize distributed energy collection.This work provides a simple and durable device that can be used to improve the performance of large-scale low-speed wind energy collection.(2)A triboelectric nanogenerator(3D Archimedes spiral structure triboelectric nanogenerator(AS-TENG))based on a three-dimensional Archimedes spiral structure was designed and manufactured to collect breeze energy.As we all know,humidity will seriously affect the output performance of triboelectric nanogenerators.Although WHNG can efficiently collect low-speed wind energy,it cannot avoid the influence of humidity in the environment.In this regard,this work designed an AS-TENG with a finned blunt body that can completely protect the TENG components in the cavity.This fully-encapsulated structure can shield the interference and damage of various factors in the environment.At the same time,it also uses the unstable characteristic of the spiral in the critical state of mechanical equilibrium to further amplify the vibration amplitude caused by the airflow.In this paper,the COMSOL Multiphysics software is used to simulate the displacement of the Archimedes spiral with different parameters under forced vibration,and the spiral with the largest displacement(N=5,Gap=8 mm,H=2 mm,W=2 mm)as a component of AS-TENG.In addition,because the combination of the spring steel sheet and the bluff body establishes a cantilever model for the collection of vibration energy,the electrical output performance of TENG at different operating frequencies was also tested when the cantilever is 7 cm.The experimental results show that when the working frequency is 0.6 Hz,the amount of charge reaches 155 n C,the short-circuit current can reach 5.2 μA,and the open circuit voltage is about 325 V.This work provides a new structure for collecting breeze energy in harsh environments,and has a huge application prospect in the field of self-powered systems. |
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