Eelectric Energy Harvesting Through Piezoelectric Polymers Progress Report - April 8 Don Jenket, II Kathy Li Peter Stone

Progress Report April 8, 2004Eelectric Presentation Overview Brief Review of Progress Quantitative Analysis of Materials Processing and Design Changes Problems Encountered Future Design Revisions Revised Timeline

Progress Report April 8, 2004Eelectric Objective DARPA Objective: Convert mechanical energy from a fluid medium into electrical energy. Fluid flow creates oscillations in an eel body Creates strain energy that is converted to AC electrical output by piezoelectric polymers AC output is stored and/or utilized Objective: Harness enough power from air flow to operate a L.E.D.

Progress Report April 8, 2004Eelectric Piezoelectric Response in Air Flow 2cm x 10cm Piezoelectric PVDF

Progress Report April 8, 2004Eelectric PZT Composite Tail

Progress Report April 8, 2004Eelectric PZT Composite Response in Air Flow PZT

Progress Report April 8, 2004Eelectric Estimation of Piezoelectric Response V = 3/8 * (t/L) 2 * h 31 *  z, t= thickness; L = Length;  z = bending radius and h 31 = g 31 *(c 11 + c 12 )+ g 33 *c 13 g 31 = 0.011[V*m/N]c 11 = 37 GN*m -2 L = 15 cm g 33 = [V*m/N]c 12 = 23.1 GN*m -2 t = 200  m  z = 2 mmc 13 = 23.1 GN*m -2 Equation taken from: Herbert, J.M., Moulson, A.J. Electroceramics: Materials, Properties, Applications. Chapman and Hall: London, If we model the tail as a cantilever:

Progress Report April 8, 2004Eelectric Comparison of Predictions PVDFPZT Composite Voltage V1.653 V “Actual” Voltage V0.496 V Sample Area12 cm 2 75 cm 2 Area-Normalized Voltage V/cm V/cm 2 1: Takes into account actual area occupied by piezoelectric material. PVDF is pure so this value is 1 times the voltage. PZT covers approximately 30 percent of the composite so its voltage is multiplied by 0.3

Progress Report April 8, 2004Eelectric “Eel Tail” Schematic II Top View Side ViewFront View Cu Wire 9.5 cm 2 cm 9.5 cm 2 cm 0.04 mm Cu Wire Silver paste Gold Electrode 2.5 cm3.5 cm Cu Wire Gold Electrode Head End Tail End

Progress Report April 8, 2004Eelectric Processing & Design Changes Wires Old: 3 mil uninsulated copper New: 5 mil insulated magnet wire Au electrode placement Old: 2.5 & 3.5 cm sections New: 2.5 & 5 cm sections Au electrode sputtering Old : Ti Sputtering New Method: Au Sputtering

Progress Report April 8, 2004Eelectric Sputtering Apparatus Pelco SC-5, Automatic High Resolution Sputter Coater Sample Chamber

Progress Report April 8, 2004Eelectric Sputtering Target Sample Chamber Sample Sputtering Au

Progress Report April 8, 2004Eelectric Problems Encountered Uncontrolled Wires Generates noise during measurements Can lead to accidents… Durability Sample severely damaged immediately before oscilloscope testing Poor adhesion between polymer layers Silver paste weakens with time -> Sample falls apart Loss on connectivity between wires and electrodes

Progress Report April 8, 2004Eelectric Future Revisions Strain Relief of Wires Reinforce Silver Paste with tape Offset Polymer Layers Allows for easier weaving and/or adhesion of wire to polymer

Progress Report April 8, 2004Eelectric Revised Timeline