A brief history on Piezoelectric Materials

Piezoelectric materials generate an electric potential across their volume when deformed.
This means that the pressure, blood flow, and movement of the heart—mechanical energy—can all potentially be harnessed, and used as a cyclical exerting force deforming the piezoelectric generator, effectively producing electrical energy.
Heart palpitations prove to be a favorable source of mechanical energy as the right ventricle changes between a volume of 29.4mL to 95.5mL with each heartbeat [17].
Of the mechanical energy available, it has been found that piezoelectric generators can have energy conversion efficiencies of up to 21.8% [16].
For the scope of this project, the main focus would be to see if piezoelectric generators are a valid addition to produce enough voltage to supplement a pacemaker battery. Even if the energy conversion ratio of the piezoelectric generator is low, it should be possible to prove that enough mechanical energy exists to supplement a battery. Future iterations of this design project could focus on methods to increase the energy conversion percentage of the piezoelectric generator.

Piezoelectric harvester used for harnessing energy from the motion of the right ventricle.

Note: this harvester would need to be downsized 1/7th of its size to meet the size constraints found inside the right ventricle.

Implementation of our testing mechanism

In order to determine the viability of piezoelectrics as a supplemental energy source for leadless pacemakers, this group performed a simple benchtop test that would displace the piezoelectric generator to determine how much energy it can produce. The PZT piezoelectric sheet would be positioned in such a way to allow it to be bent by the movement of an arm attached to a servo motor. This is done so as to imitate the ventricle walls relaxing and contracting during every heartbeat. The PZT piezoelectric sheet would be connected to an oscilloscope allowing voltage measurements to be recorded. It is crucial that this benchtop test deforms the piezoelectric sheet by an amount similar to that caused by ventricle wall contraction. This benchtop test will also provide the maximum potential energy that the piezoelectric sheet could produce given variations in right ventricle size and space as seen in different patients.

3D Printed components mounted onto the servo motor (note the rail arm is missing).

Edited by André Loyola

Page updated

Report abuse