Eelectric
Energy Harvesting
Through Piezoelectric Polymers
Progress Report - April 8
Don Jenket, II
Kathy Li
Peter Stone
Presentation Overview
Brief Review of Progress
Quantitative Analysis of Materials
Processing and Design Changes
Problems Encountered
Future Design Revisions
Revised Timeline
April 8, 2004
Eelectric
Progress Report
Objective
DARPA Objective: Convert
mechanical energy from a fluid
medium into electrical energy.
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
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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
3.082 Objective: Harness
enough power from air flow to
operate a L.E.D.
April 8, 2004
Eelectric
http://www.darpa.mil/dso/trans/energy/pa_opt.html
Progress Report
Piezoelectric Response
in Air Flow
2cm x 10cm Piezoelectric PVDF
April 8, 2004
Eelectric
Progress Report
PZT Composite Tail
http://web.media.mit.edu/~testarne/TR328/node7.html
April 8, 2004
Eelectric
Progress Report
PZT Composite
Response in Air Flow
PZT
April 8, 2004
Eelectric
Progress Report
Estimation of
Piezoelectric Response
If we model the tail as a cantilever:
V = 3/8 * (t/L)2 * h31 * dz,
t= thickness; L = Length; dz = bending radius and
h31 = g31*(c11 + c12)+ g33*c13
g31 = 0.011[V*m/N]
c11 = 37 GN*m-2
L = 15 cm
g33 = 0.025 [V*m/N]
c12 = 23.1 GN*m-2
t = 200 mm
dz = 2 mm
c13 = 23.1 GN*m-2
Equation taken from: Herbert, J.M., Moulson, A.J. Electroceramics: Materials, Properties, Applications. Chapman and Hall: London, 1990.
April 8, 2004
Eelectric
Progress Report
Comparison of Predictions
Voltage
PVDF
0.7322 V
PZT Composite
1.653 V
“Actual” Voltage1
0.7322 V
0.496 V
Sample Area
12 cm2
75 cm2
Area-Normalized 0.0610 V/cm2
Voltage
0.0066 V/cm2
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
April 8, 2004
Eelectric
Progress Report
“Eel Tail” Schematic II
9.5 cm
2.5 cm 3.5 cm
Tail End
Head End
2 cm
Gold
Electrode
Cu Wire
Top View
Gold Electrode
Cu Wire
Cu Wire
0.04 mm
Silver paste
9.5 cm
2 cm
Side View
April 8, 2004
Front View
Eelectric
Progress Report
Processing &
Design Changes
Wires
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Old: 3 mil uninsulated copper
New: 5 mil insulated magnet wire
Au electrode placement
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Old: 2.5 & 3.5 cm sections
New: 2.5 & 5 cm sections
Au electrode sputtering
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April 8, 2004
Old : Ti Sputtering
New Method: Au Sputtering
Eelectric
Progress Report
Sputtering Apparatus
Sample Chamber
Pelco SC-5, Automatic High Resolution Sputter Coater
April 8, 2004
Eelectric
Progress Report
Sputtering Target
Sample
Sputtering Au
Sample Chamber
April 8, 2004
Eelectric
Progress Report
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

April 8, 2004
Eelectric
Progress Report
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
April 8, 2004
Eelectric
Progress Report
Revised Timeline
2/10
2/17
2/24
3/2
3/9
3/16
3/23
4/6
4/13
4/20
4/27
5/4
Electroded piezoelectronic sample
Obtain PVDF
Investigate electrode technology
Attach electrodes to PVDF
Preliminary measurements
Build Prototype
Electronic Circuitry
Environment Protection
Construct Housing/Barrier
Test Prototype
Air testing
Output measurement
Optimizing Prototype
Build prototype II
Test protoype II
Incorporating future revisions
Prepare Demo
Final Presentation
April 8, 2004
Eelectric
Progress Report
5/11