Design And Research Of Raindrop Energy Collector Based On Hydrophobic Heterogeneous Structure

There has been a constant search for solutions to the problem of energy scarcity.The use of renewable energy in nature for electrical energy harvesting has always been of great interest to academics.However,raindrop energy,a renewable resource that is widely available in nature and has great potential for application,has often been overlooked.Traditional research on raindrop energy harvesting is based on the electromechanical conversion of raindrops against piezoelectric elements,but the impact of residual droplets on the output performance of piezoelectric elements cannot be addressed.In this paper,based on the piezoelectric vibration energy harvesting technology to convert the kinetic energy of raindrops into electrical energy,a raindrop energy harvester based on hydrophobic heterogeneous structure was designed,whose special groove-hole structure enabled the rapid evacuation of the residual droplets on the surface when raindrops hit the composite piezoelectric sheet.The output waveforms during continuous rainfall and the output,when random raindrops fall,were simulated.The output performance of the composite piezoelectric sheet with different structures were compared under various experimental conditions to test the superiority of the hydrophobic heterogeneous structure adopted in this harvester.Based on the results,the composite piezoelectric sheet with the groove-hole heterostructure showed the best hydrophobic effect and the best output performance,with a maximum output voltage of 6.112 V at a drop height of 150 cm.Also,the composite piezoelectric sheet in this study had an output power of 2.638 μW at a drop height of 110 cm and a load resistance of 7.1 MΩ,which was 1.99 times the maximum output power of conventional polyvinylidene fluoride(PVDF)piezoelectric films under the same experimental condition.Besides,in order to store or supply the converted electrical energy to a greater extent,an adaptation study of the back-end interface circuit was done and an improved resonant interface circuit and an improved resonant interface series circuit suitable for the series structure of the raindrop energy harvester array were designed.And the simulation results showed that the charging efficiency of the improved resonant interface circuit was 400 times that of the standard energy harvesting circuit and 257 times that of the classical synchronous charge extraction interface circuit,and the charging efficiency of the improved resonant interface series circuit was 798 times that of the standard energy harvesting series circuit,resulting in a significant increase in energy storage capacity.Therefore,the energy collected by the raindrop energy harvesting system could help to alleviate the energy shortage problem to a certain extent and effectively use clean and renewable energy from the environment to power micro and small electronic devices.