Energy harvesting with polymers, ferroelectrets and ... · Energy harvesting with polymers,...
Transcript of Energy harvesting with polymers, ferroelectrets and ... · Energy harvesting with polymers,...
Energy harvesting with polymers, ferroelectrets and piezocomposites
Prof. Chris Bowen
Department of Mechanical Engineering
University of Bath
Future Smart Applications for Elastomers
27 March IoM3
Ferroelectric Materials
• Below the Curie temperate (Tc) the
crystal structure distorts to tetragonal
structure.
• Zr4+ or Ti4+ ion displaced from the
centre, creating an electric dipole.
Cubic and
Symmetrical
(above Curie T)
Tetragonal and
non-symmetrical
(below Curie T)
O2-
Pb2+
Ti4+, Zr4+
Ferroelectrics
Tetragonal Rhombohedral
6 polarisation directions
8 polarisation directions
Ferroelectric polymers:
Poly(vinylidene fluoride)
http://www.physics.montana.edu/eam/polymers/images/Piezoe5.jpg
Poling – achieving piezo response
This ‘freezes in’ the alignment of the domains, resulting in a net polarisation.
Dipoles are orientated within domains.
Dipoles randomly orientated.
To achieve net polarisation apply a high electric field at elevated temperatures.
Cool to room temperature (with the electric field still applied).
• Electric field parallel to the poling direction (polar axis) extends the material.
• Electric field opposite to the polar axis results in contraction.
• This is the actuator mode of operation.
• Strains are small ~0.1-0.3%
• PVDF even smaller – also low force (low stiffness)
Converse Piezoelectric Effect
Extension Contraction
0
500
1000
1500
2000
2500
3000
3500
-3.0 -2.0 -1.0 0.0 1.0 2.0 3.0
Electric Field (kVmm-1
)
Str
ain
(p
pm
)
Extracted fibre
response
Direct Piezoelectric Effect
• Tensile or compressive force parallel to the poling direction (polar axis)
generates a potential difference across opposing faces.
• This is the sensing/generator mode of operation.
d33 ~ 2 x d31
Charge per unit force
PZT 300-600 pC/NPVDF 20-30pC/N
gij = dij/ permittivity
electric field per unit stress
PZT permittivity > 1000PVDF permittivity ~ 10
Generator modes
Novel Energy Materials: Engineering Science and Integrated Systems (NEMESIS) Grant agreement no.: 320963
@BowenNEMESIS
Peter Harris
Dan Zabek
E. Le Boulbar
Vaia Adamki
James Roscow
Andrew Avent
Oliver Weber
Energy Harvesting
• Inertial energy harvesting: relies on the resistance to acceleration of a mass.
Base movement sets up a vibration in a mass-spring system, from which electrical
energy can be extracted. Vibration amplitude at resonance can be significantly
larger than the amplitude of the base movement.
• Kinematic energy harvesting directly couples the energy harvester to the relative
movement of different parts of the source.
Examples include bending of a tyre wall to monitor type pressure, or the flexing and
extension of limbs to power mobile communications. Do not rely on inertia or
resonance. Since the strain in the harvester is directly coupled to a flexing or
extension of the source, they are connected at more than one point.
Intertial - Resonant Energy Harvesters
Linear: Works at specific frequency
BUT: Ambient vibrations can exhibit:
(i) multiple time-dependent frequencies(ii) may change with time(iii) can include components at relatively low frequencies
Intertial – Bistable CRFP Laminate Energy Harvesters
• Bistable systems have broadband
energy harvesting characteristics due to
nonlinearity (e.g. cantilever beam in a
magnetic field)
Why CFRP laminates? (i) no stray
magnetic fields; small volume (ii) laminate
combined with piezoelectric materials (iii)
tailor laminate lay-up, elastic properties
and geometry.
Arrieta, Inman APL 2012
Bistable harvesting – the energy landscape
Harne et al. Smart Mater. Struct. 22 (2013) 023001
x,y curvature-energy map for bistable
Rotation and embedding
PZT (200mm) fibre/electrode/insulator in [0/90]T
Image courtesy of Mustafa ArafaAssociate Professor, American
University in Cairo
Kinematic - Bonded Devices
Battery-and wire-less tire pressure measurement systems (TPMS) sensor Noaman Makki • Remon Pop-Iliev , Microsyst Technol (2012) 18:1201–1212
Kinematic - Bonded devices
Smart Mater. Struct. 21 (2012) 015011, Direct strain energy harvesting in automobile tires using piezoelectric PZT–
polymer composites , D A van den Ende et al.
Development of a piezoelectric energy harvesting system for implementing wireless sensors on the tires
Lee et al. Energy Conversion and Management 78 (2014) 32–38
1.4μW/mm3
Electro-active polymers
Comparison of electroactive polymers for energy scavenging applications Smart Mater. Struct. 19 (2010) 085012
C Jean-Mistral S Basrour and J-J Chaillout
Polypower Energy Scavenger, 2013 Int Conf. Circuits, Power and Comp. Tech
Ferroelectrets: Cellular non-polar piezoelectric polymers
PTFE
PTFE
FEP
45mm
45mm
Metal mesh
Force
Force
Metal mesh
d33 100-500pC/N d33 (PVDF) <20pC/N d33 (PZT) ~ 500pC/N
A A
Grounded Grid
PTFE
Corona Point
Metal reference
plateSample
Conducting
substrate
M. Gerard, C. R. Bowen, F. H. Osman, Processing and Properties of PTFE-FEP-PTFE Ferroelectret Films,Ferroelectrics, 422:59–64, 2011
Tribo-electric generators
Single-Electrode-Based Rotating Triboelectric Nanogenerator for Harvesting Energy from Tires Hulin Zhang, Ya Yang,Xiandai Zhong, Yuanjie Su, Yusheng Zhou, Chenguo Hu, and Zhong Lin Wang
ACS Nano, 2014, 8 (1), pp 680–689
Pyroelectric harvesting
• Thermoelectric – harvesting
temperature gradients
• Pyroelectrics – harvesting
temperature fluctuations
Sidney Lang, Physics Today.
Micro-patterning of PVDF (Daniel Zabek)
D Zabek, J Taylor, EL Boulbar, CR Bowen, Micropatterning of Flexible and Free Standing Polyvinylidene Difluoride
(PVDF) Films for Enhanced Pyroelectric Energy Transformation, Advanced Energy Materials (2015)
Micro-pattering PVDF
88% coverage
45%
63%
28%
Pre-poled extruded PVDF
Photolithograpiic process
Physcial vapour deposition of electrode
Temperatures less than 60°C
Variable geometry/substrate
Durable electrode bonding
Up scaleable
Pattern quality >95%
Temperature, closed circuit current, open circuit voltage
0 10 20 30 40 50 60
-40
-30
-20
-10
0
10
20
30
40
Curr
ent
[nA
]
time [sec.]
45%
70%
88%
100%
0 10 20 30 40 50 60
-60
-40
-20
0
20
40
60
Volt
[V
]
time [sec.]
45%
70%
88%
100%
0 10 20 30 40 50 6035.5
36
36.5
37
37.5
38
38.5
39
39.5
40
40.5
Tem
pera
ture
[C
]
time [sec.]
45%
70%
88%
100%
Benefits for porosity in energy harvesting ?
Vibration (piezo)
..also lower heat capacity (increased ΔT).
Heat (pyro)
Summary
Plenty ‘Harvesting’materials
– Ferroelectric polymers and ceramics
– Composites systems
– Electrets
– EAPs
– Triboelectric
– Resonant and non-resonant
– Inertial and kinematic
– Linear and non-linear
– Finding key applications and matching desired power with surrounding environment
Funders:
European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013) / ERC Grant
Agreement no. 320963 on Novel Energy Materials, Engineering Science and Integrated Systems (NEMESIS)
EPSRC, UoB EPSRC KTA, Leverhulme Trust, Royal Society, FP6/7, TSB/DTI, DSTL/Team MAST, NPL, GWR, Airbus,
Moog, Meggit, Renishaw
Reading
C. R. Bowen, H. A. Kim, P. M. Weaver and S. Dunn, Piezoelectric and ferroelectric
materials and structures for energy harvesting applications, Energy and Environmental
Science, DOI: 10.1039/c3ee42454e (2014)
C. R. Bowen, J. Taylor, E. LeBoulbar, D. Zabek, A. Chauhan and R. Vaish, Pyroelectric
materials and devices for energy harvesting applications, Energy & Environmental Science,
DOI: 10.1039/c4ee01759e (2014)
J. Zhang, C. Wang and C. Bowen, Piezoelectric effects and electromechanical theories at
the nanoscale, Nanoscale, DOI: 10.1039/c4nr03756a (2014)
C. R. Bowen and M. H. Arafa, Energy Harvesting Technologies for Tire Pressure Monitoring
Systems, Advanced Energy Materials, 1401787 (2014)