Nano-energy source integrated integrated friction-electromagnetic hybrid generator

(a) Schematic diagram of rotating sleeve type friction nano-generators. (b) Frictional nanogenerators and electromagnetic induction generators achieve impedance matching.

Electromagnetic induction generators are currently the main power generation methods for power supply, but electromagnetic induction generators have lower output power at low frequencies, and there is still room for improvement in the efficiency of converting mechanical energy into electrical energy. In recent years, as a new era of energy, frictional nanogenerators have made remarkable achievements in collecting low-frequency mechanical energy. Low-cost, simple-to-prepare frictional nanogenerators utilize frictional electrification and electrostatic induction to efficiently convert low-frequency mechanical energy into electrical energy.

Therefore, combining frictional nano-generators and electromagnetic induction generators can make up for the shortage of electromagnetic induction generators to collect energy at low frequencies, and has the potential to further increase the energy conversion efficiency. However, the nature of the two is very different. The frictional nanogenerator is equivalent to a current source, and the electromagnetic induction generator is equivalent to a voltage source. The internal resistance of the two is very different. For hybrid generators, the maximum output power can only be achieved when the two generators are operating under internal impedance matching conditions. Therefore, how to solve the problem of impedance matching between frictional nano-generators and electromagnetic induction generators and integrate them into the difficulties in the research of hybrid generators.

In response to the above problems, under the guidance of the director of the Beijing Institute of Nano Energy and Systems, Chinese Academy of Sciences, Wang Zhonglin, a foreign academician of the Chinese Academy of Sciences, and researcher Li Congju, the graduate students Cao Yu and others were inspired by the structure of a commercial electromagnetic induction generator to prepare a Rotating-sleeve friction-electromagnetic hybrid generators that highly integrate frictional nanogenerators and electromagnetic induction generators. Without affecting the work of the electromagnetic induction generator, frictional nano-generators are used to further collect the rotating mechanical energy and achieve efficient collection of mechanical energy. In addition, the hybrid generator realizes the impedance matching of the friction nano-generator and the electromagnetic induction generator under the condition that only the commercial transformer is used, thereby greatly reducing the loss of energy in the complicated management circuit.

The experimental results show that frictional nanogenerators and electromagnetic induction generators can be efficiently combined under the action of a transformer: at a speed of 250 rmp, the hybrid generator has a matched internal resistance of 8 kΩ and an output power of up to 14 mW. The rotary-sleeve friction-electromagnetic hybrid generator can not only collect mechanical energy such as wind energy, water energy, rotational energy, etc. in the environment, but also can increase the utilization efficiency of low-frequency mechanical energy in combination with the current commercial electromagnetic induction generator device. Practical value and great commercial prospects.

The relevant research results were published on the recent ACS nano (DOI: 10.1021/acsnano.7b03683).