Crack Protective Layered Architecture of Lead-Free Piezoelectric Energy Harvester in Bistable Configuration

Abstract

Kinetic piezoelectric energy harvesters are used to power up ultra-low power devices without batteries as an alternative and eco-friendly source of energy. This paper deals with a novel design of a lead-free multilayer energy harvester based on BaTiO3 ceramics. This material is very brittle and might be cracked in small amplitudes of oscillations. However, the main aim of our development is the design of a crack protective layered architecture that protects an energy harvesting device in very high amplitudes of oscillations. This architecture is described and optimized for chosen geometry and the resulted one degree of freedom coupled electromechanical model is derived. This model could be used in bistable configuration and the model is extended about the nonlinear stiffness produced by auxiliary magnets. The complex bistable vibration energy harvester is simulated to predict operation in a wide range of frequency excitation. It should demonstrate typical operation of designed beam and a stress intensity factor was calculated for layers. The whole system, without presence of cracks, was simulated with an excitation acceleration of amplitude up to 1g. The maximal obtained power was around 2 mW at the frequency around 40 Hz with a maximal tip displacement 7.5 mm. The maximal operating amplitude of this novel design was calculated around 10 mm which is 10-times higher than without protective layers.

Experimentally Verified Analytical Models of Piezoelectric Cantilevers in Different Design Configurations

“…can be supplemented. Moreover, the single DOF model can easily be extended to support calculations of strain and stress levels within the beam's layers to determine a maximal allowable load as shown in [31].…”

Properties of Car-Embedded Vibrating Type Piezoelectric Harvesting System

“…2021, 11, 7449 2 of 12 impedance matching between an external mechanical vibration signal and the mechanical characteristics of a piezoelectric device, the usable approach is to match the resonant frequency of the piezoelectric generator with the ambient frequency of environmental vibration [16,17]. Mechanically matching the resonance frequency of a piezoelectric generator with that of an external vibration source is the most realistic scavenging system method based on piezoelectricity [18][19][20]. However, matching two frequencies is difficult because the ambient vibration in a vehicle is in a variable state [21][22][23].…”