Magnetic Force Enhanced Sustainability and Power of Cam-Based Triboelectric Nanogenerator

Abstract

Since the first invention of triboelectric nanogenerators (TENGs) in 2012, many mechanical systems have been applied to operate TENGs, but mechanical contact losses such as friction and noise are still big obstacles for improving their output performance and sustainability. Here, we report on a magnet-assembled cam-based TENG (MC-TENG), which has enhanced output power and sustainability by utilizing the non-contact repulsive force between the magnets. We investigate the theoretical and experimental dynamic behaviors of MC-TENGs according to the effects of the contact modes, contact and separation times, and contact forces (i.e., pushing and repulsive forces). We suggest an optimized arrangement of magnets for the highest output performance, in which the charging time of the capacitor was 2.59 times faster than in a mechanical cam-based TENG (C-TENG). Finally, we design and demonstrate a MC-TENG-based windmill system to effectively harvest low-speed wind energy, ~4 m/s, which produces very low torque. Thus, it is expected that our frictionless MC-TENG system will provide a sustainable solution for effectively harvesting a broadband of wasted mechanical energies.

Self-powered triboelectric sensor for cooling fan monitoring

“…Therefore, the electrical output of the F-TES increased when the ∆t decreased. These results were in accordance with the results of the previous study [32], as the output performance of the TENG could be increased by a decrease in ∆t. Crest factor is defined as the ratio of the peak to the root mean square (RMS) value of output voltage and current of TENG [34][35][36].…”

“…∆t 1 is the time interval between the positive peak and negative peak values, and ∆t 2 is the time interval between the positive peak values or the negative peak values. From previous research it was determined that the electrical output of a TENG increases by a decrease in ∆t [32]. Thus, when the rotational speed of a cooling fan decreases, the output voltage of our F-TES decreases, so that we can monitor the operational status of a cooling fan.…”

“…This result was due to the change in ∆t. According to the previous study [32], the short-circuit current I sc was determined using the following equation :…”

“…where S is the contact area, σ is the total static tribo-charge of the tribo-surfaces caused by contact electrification and electrostatic induction, ε r is the relative dielectric constant, d is the thickness of the electron acceptor, and x(t) and v(t) are the distance and velocity between the electron donor and acceptor, respectively [32]. As mentioned above, we could monitor the operational status of cooling fan due to the change in output current from F-TES according to the rotational speed, as shown in figure 3(a).…”

Recent Advances in Triboelectric Nanogenerators: From Technological Progress to Commercial Applications

“…In this section, we review cam-based TENG assembled with the windmill system to harvest wind energy. , Among many kinds of cam-based TENG designs, ,,, the cam-based TENG integrated to the windmill , has a simple design compared to others structure. The cam-based TENG can be a sliding mechanical cam shape, , or the bearing integrated cam shape, ,, or magnetic-assembled cam to transfer the rotary motion into linear motion. Two kinds of cam-based TENG assembled with the windmill design (mechanical cam and magnet-assembled cam) are presented.…”