A packaged piezoelectric vibration energy harvester with high power and broadband characteristics

This paper presents the new design and fabricating process of a packaged micro piezoelectric vibration energy harvester (PVEH). Structures are designed and parameters are optimized through finite element modelling and analysis. The double L-shaped tungsten proof mass block and thick copper-based PZT bimorph are proposed to ensure the harvester with high electrical power. Polymethyl methacrylate (PMMA) packaging and epoxy resin bonding supply the flexible clamping of piezoelectric cantilever, which decreases the resonant frequency, increase average PZT stress, reduces the maximum PZT stress and broadens the effective frequency range. Bulk PZT bonding is used in PVEH prototype fabrication. Experimental results show that the packaged PVEH resonates under the excitation of 1 g (9.8 m s(-2)) at 160 Hz. It has an optimum resistance load of 47 k Omega. More importantly, its maximum output power is 2.49 mW in experiments, and the half-power bandwidth is 22 Hz. After package, it has a high volume power density of 0.64 mW/cm(3) g(2) with the volume of 3.9 cm(3) (2 cm x 1.5 cm x 1.3 cm). Connected with energy harvesting circuit, PVEH can light up a light emitting diode (LED) under broadband vibration frequency. The proposed PVEH with broadband output power in mW level is promised to power up some microelectronic devices for application. (C) 2019 Elsevier B.V. All rights reserved.