Promoting smart cities into the 5G era with multi-field Internet of Things (IoT) applications powered with advanced mechanical energy harvesters

Piezoelectric energy harvester for rolling bearings with capability of self-powered condition monitoring

Recent progress in blue energy harvesting for powering distributed sensors in ocean

Wind energy plays an increasingly important role in alleviating the shortage of fossil fuel energy because of the emerging promising technologies such as electromagnetic generators (EMGs), triboele...

A Triboelectric–Electromagnetic Hybrid Nanogenerator with Broadband Working Range for Wind Energy Harvesting and a Self-Powered Wind Speed Sensor

A triboelectric nanogenerator (TENG) has great advantages in harvesting low-frequency mechanical energy, which is very suitable for energy harvesters and active sensors for breeze wind. Here, we report a breeze-wind-driven autonomous wireless anemometer (WWA) based on a planetary rolling triboelectric nanogenerator (PRTENG) for simultaneous wind energy harvesting and wind speed sensing. Benefitting from the planetary rolling friction, the PR-TENG can be activated at a wind speed of less than 2 m/s. At a wind speed of 5 m/s, the W-WA can be continuously powered and autonomously transmit wind speed data in the range of 10 m every 2 min. By integrating the TENG-based micro/nanoenergy harvester and active sensor, this work has realized a complete self-powered intelligent wireless sensing system, which has exhibited broad prospects in distributed micro/nanoenergy, unattended environmental monitoring, and the Internet of things. Wind as a kind of widely distributed and renewable energy has played a significant role in electric supply and contributed to alleviate the energy crisis. According to statistics, the exploitable part of global wind energy is up to 5.3 × 10 kWh per year. On the other hand, the anemometer is a powerful device for wind monitoring and weather forecasting that usually works in unattended environment and needs a long service life. Up to now, the anemometer is mainly supplied by short-term battery, which greatly increases the maintenance cost and environmental pollution. Therefore, harvesting wind energy from the ambient environment to power the anemometer is an optimal method to realize sustainable operation. As a new energy technology, the triboelectric nanogenerator (TENG) based on Maxwell’s displacement current was first proposed in 2012 and has been widely used as an energy harvester and active sensor. As an energy harvester, the TENG has a better output performance for harvesting lowfrequency and weak mechanical energy compared to a traditional electromagnetic generator, which can provide sustainable micro/nanopower sources for distributed electronic devices. As an active sensor, the TENG-based active sensor has the advantages of being lightweight, high flexibility, and an abundant selection of materials compared with the electromagneticor piezoelectric-based active sensor. Some TENG-based wind energy harvesters and sensors have been studied to harvest and monitor wind energy effectively. Although the TENG-based active wind sensor can directly convert wind information into sensing electrical signal without a power supply, the signal processing and transmission still need an external power supply for this kind of active sensor. If a TENG-based wind sensor can be supplied by a TENG-based power source, it is very promising to realize a fully self-powered system for autonomous wind

Breeze-Wind-Energy-Powered Autonomous Wireless Anemometer Based on Rolling Contact-Electrification

A magnetically coupled bistable piezoelectric harvester for underwater energy harvesting

Small-scale wind energy harvesting, which can replace batteries to power small electronic devices and realize self-powered systems, has been extensively studied. To improve the working wind-speed range and output power of small-scale wind energy generation systems, we propose a synergetic hybrid piezoelectric and triboelectric mechanism for galloping wind energy harvesting. In this mechanism, a piezoelectric energy harvester (PEH) works in the vibration area and starts working at low wind speeds, while triboelectric nanogenerators work at the vibration boundaries and cooperate with the PEH at high wind speeds. The triboelectric nanogenerator boundaries can (1) constrain the maximum deformation of the beam at high wind speeds to avoid damage to the PEH, (2) increase the vibration frequency to enhance the electromechanical conversion efficiency, and (3) allow the PEH to have a low equivalent stiffness to work effectively at low wind speeds. A dynamic model is presented to characterize the synergetic hybrid piezoelectric–triboelectric wind energy harvester (SHPTWEH) and this is verified by experiments. The results show that the triboelectric nanogenerator boundaries greatly expand the effective working wind-speed range, and the total average power output by the prototype SHPTWEH was 0.24 mW at a wind speed of 14 m/s, which was 2.3 times that of the PEH alone.

A synergetic hybrid mechanism of piezoelectric and triboelectric for galloping wind energy harvesting

The invention relates to a flexible strong-drive type human body energy collector. The energy collector comprises a composite power generation device, a rope and a human body fixed end; the compositepower generation device comprises a frequency increasing gear, a reset spring, an inner ratchet wheel, a permanent magnet installation wheel, permanent magnets, an induction coil and a piezoelectric buckling beam. The frequency increasing gear is fixed on a bottom plate; the frequency increasing gear is meshed with an end gear of the inner ratchet wheel; the tooth number of the frequency increasing gear is greater than that of the end part gear of the inner ratchet wheel; the reset spring is installed between the frequency increasing gear and the bottom plate; the permanent magnet installationwheel is driven by the inner ratchet wheel to rotate unidirectionally, the permanent magnets are embedded in the permanent magnet installation wheel in a circumferential array, and the inner ratchetwheel and the permanent magnet installation wheel are both mounted on the top plate; an energy management circuit board and an induction coil are both mounted on the top plate, and the energy management circuit board is electrically connected with the induction coil and the piezoelectric buckling beam. According to the invention, the damage to a human body caused by long-time wearing friction of amechanical structure can be avoided, the influence on human body movement is reduced as much as possible, and a high driving force is achieved.

Flexible strong-drive type human body energy collector

The invention relates to a self-generating virus-killing and sustainable electrostatic adsorption mask. The mask comprises a mask body and a rope pull type human body motion energy collector, and themask body is worn on the face of a human body. The rope pull type human body motion energy collector is fixed to the buttocks of the human body. The two are connected through a wire, the mask body comprises an outer layer, a heating layer, an electrostatic adsorption layer, a heat insulation layer, a skin-friendly layer and elastic ropes arranged on the two sides of the outer layer. The outer layer, the heating layer, the electrostatic adsorption layer, the heat insulation layer and the skin-friendly layer are sequentially arranged from outside to inside, the rope pull type human body movementenergy collector is used for collecting movement energy of a human body and continuously supplying power to the heating layer and the electrostatic adsorption layer of the mask body, the heating layer continuously heats to inactivate viruses, and the electrostatic adsorption layer is continuously used for electrostatic adsorption filtration; and the mask has a sustainable electrostatic adsorptionfiltering function, viruses which are adsorbed on the mask and are sensitive to temperature can be killed, the use time and frequency of the mask are increased, and the use safety and reliability ofthe mask are remarkably improved.

Li Meng

Papers

A magnetically coupled bistable piezoelectric harvester for underwater energy harvesting

A synergetic hybrid mechanism of piezoelectric and triboelectric for galloping wind energy harvesting

Flexible strong-drive type human body energy collector

Self-generating virus-killing and sustainable electrostatic adsorption mask