Research On Design And Manufacturing Technology Of Piezoelectric Micro Battery For Vibration Energy Scavenging

As the development of MEMS, a lot of MEMS devices are manufactured, but how to power them becomes one of the most important problems. The traditional solution is to use batteries, but they are undesirable for many reasons: they tend to be quite bulky, contain a finite amount of energy, and have a limited shelf life. So it is very necessary to research long lifetime and microminiature cells.Energy harvesting from the environment has been actively explored using several methods. Most of all, mechanical vibration, existing everywhere around us and without pollution, is a potential power source which is easily accessible through MEMS technology. There are three basic mechanisms by which vibrations can be converted to electrical energy: electro-magnetic, electrostatic and piezoelectric. In this paper the piezoelectric conversion is explored to convert mechanical energy to electrical energy.A micro-cantilever beam with a seismic mass added to the end is designed in this paper. When the system is stimulated by ambient vibration sources, the mechanical structure deforms, stresses are then induced in the piezoelectric material and electric charge is generated with direct piezoelectric effect. Storing this kind of energy through capacitors or rechargeable batteries can be used as a micro battery to drive micro-power apparatus.Firstly the design and simulation of the piezoelectric micro battery are implemented. According to the theory of the mass-spring-damper system, the structure of the micro cantilever beam is established. The conversion theory is derived simply based on the material mechanics and piezoelectric theory. Using Finite-element analysis software ANSYS 8.1, the relations of geometric parameters of the cantilever beam vs natural frequencies and potential differences are obtained through modal analysis and harmonic analysis. This result can be used to design and manufacture the cantilever beam in the future.PZT ferroelectric film is a key technique for the conversion of mechanical energy to electrical energy. In this paper, Sol-Gel technique is employed to prepare a PZT piezoelectric thin film. Experimentally, by adjusting the concentration and mixture radio of the solution, temperature of the water bath and so on, the transparent and stable precursor solution is obtained. By changing the velocity and time of spin-coating, annealing temperature and otherwise, the PZT film shows good surfacing, without cracks, and preferred (111) orientation.