Research on dynamics of bouncing ball in triboelectric nanogenerator

Bouncing ball based Triboelectric Nanogenerator (BB-TENG) can be used to harvest vibrational energy and sense signal for self-powered sensor in the non-resonant zone because of its non-spring vibration system. The energy harvesting efficiency and sensing effectiveness are significantly affected by the dynamics of the bouncing ball. However, due to the chaotic and nonlinear mechanics, the dynamics of the bouncing ball inside BB-TENG and the corresponding influencing factors have not yet been revealed, which restricts the development of high-efficiency BB-TENG. In this work a method based on dynamics simulation and test bench experiment is to be proposed and the 'Takeoff', 'Well-Contact', 'Self-Spin', and 'Rich-Contact' of the bouncing ball with the plate electrodes will be investigated. The kinetic model established based on the Automatic Dynamic Analysis of Mechanical Systems (ADAMSs) is verified through experiments to confirm the reliability of the simulation results. It is found that 'Well-Contact' of the bouncing ball makes BB-TENG harvest energy efficiently. The factors for 'Well-Contact' and their influence are investigated, and the critical frequencies for 'Well-Contact' of the bouncing ball at each vibration excitation amplitude are obtained. 'Self-Spin' of the bouncing ball produced by unbalanced excitation torque is found to increase energy harvesting, and the excitation frequency significantly determines the energy of the 'Self-Spin'. When the external excitation acceleration reaches a critical value, the 'Rich-Contact' of the bouncing ball is found, and the amount of charge transfer for BB-TENG will not increase, which is termed saturated condition. Therefore, the results of this work help improve the design and application of high-efficiency BB-TENG.