Post on 17-Apr-2020
X. Zhao, A.G. Cook, H. Assender, C. Johnston, M. Johnson1 andPatrick Grant
Department of Materials, Oxford University.
1School of Electrical & Electronic Engineering, Nottingham University.
Novel High Energy Density, High Reliability Capacitors
IeMRC award 774613 and DSTL award RD020-013644, further supported by Rolls-Royce, Norfolk Capacitors, Scott Bader and Nanion
Outline
The more electric airframe
Power capacitors
Nanocomposite dielectrics
Progress
Conclusions and future directions
Rudder
ElevatorsLoads
Load
Generator
Power control
Load centre
Transmission
Transmission& Distribution
Galleys
Avionics
TE flaps
Spoilers
Ailerons
Gear
LoadsLights
Loads
Cabinservices
ECScompressor
Loads
Lights
APU generator
powerconverter
Fuelpump
250kW generator
LE flaps
LightsAnti-ice
Loads
250kW generator
More electric aircraftFeatures
Electrical startingElectro-hydraulic actuators / Electro-mechanical actuatorsElectrical anti-iceModified cabin environmental systemSimplified engine-airframe interface
DeletingThree major hydraulic systemsRam-air turbineCabin-air bleedsPneumatic anti-ice
ECScompressor
More electric aircraft
For a 200 passenger B767-type aircraft:10% reduction in aircraft empty weight
13% reduction in required engine thrust
9% reduction in fuel burn
significant reduction in emissions[NASA]
“Global electrical optimisation is the only way to achieve meaningful improvements in the total airframe package”
M.J. Provost, Advanced Propulsion Systems Design, Rolls-Royce, Proc Int. Conf. IEE Power Electronics, Bath, 2002
Power capacitors
Increased electrical power generation – 1MWIncreased power conditioning Current high value capacitors based on electrolytics or polymer filmsHeavy (~40% of converter), temperature limited (~70°C), catastrophic failure modes ⇒ the “weakest link”Combining a high permittivity nanoscale ceramic powder with a high temperature polymer film to produce a high performance dielectric nanocomposite
Nanocomposite dielectric materials
Ceramic particles in polymersAdd nanoparticles to increase dielectric constant to 30-50 (Cα ε)
ButThin films (C α 1/t)Do not undermine breakdown strength (u α E2)Do not compromise processability into large areasDo not increase density more than necessary
Properties up to 200ºCDevelop a scaleable manufacturing technology
Objectives
To investigate the manufacturability of polymer based nanocomposite films for power capacitor applications at the laboratory and near industrial scale.To undertake performance and reliability testing and to relate performance to processing and microstructural features.
Manufacturing technology
Spray deposition Web coating
Lab-scaleProof of concept
Lab-scaleProof of concept
Intermediate scale Near industrial scale
Industrial collaborators
Manufacturing technology
Pre-heated table
Syringe pumps with nano suspensions
Hypodermic needle(s)
Compressed air
X-Y manipulator linear drives
Sputtercathode
Evaporation
E-beam
Monomerdelivery
Rotatingdrum
Roll-to-roll
Spray deposition
Spray nozzle
Compressed air
Hypodermic needle
TPGDA/BaTiO3/MEK:EtOH suspension
Syringe
Syringe pump
Atomized droplet spray
xy
Pre-metallizedglass substrate
Heated plate moving in x-y
Spray nozzle
Compressed air
Hypodermic needle
TPGDA/BaTiO3/MEK:EtOH suspension
Syringe
Syringe pump
Atomized droplet spray
xy
Pre-metallizedglass substrate
Heated plate moving in x-y
Acrylate-BaTiO3 films
SEM micrograph of PTPGDA-30vol%BaTiO3 film at an accelerating voltage of 2.0 kV.
Acrylate-BaTiO3 films
Dielectric constant and dissipation factor (tan δ) of spray deposited PTPGDA-BaTiO3 nano-composites at 25°C as a function of frequency for various volume fractions of BaTiO3.
Acrylate-BaTiO3 films
Comparison of experimental data and theoretical predictions of ε for PTPGDA-BaTiO3 nanocomposites
Spray deposition of polymer nanocomposite films for dielectric applications, X. Zhao et al, Mat. Sci. Eng. B. in the press.
Perfluoro alkoxy CNT films
SEM micrographs of as-grown aligned arrays of(a) 100μm x 50nm multi-wall carbon nanotubes (MWNT-1),(b) 500μm x 50nm (MWNT-2), and(c) and (d) after sonication.
PFA-CNT films
Dependence of dielectric permittivity and AC conductivity of:(a) PFA-MWNT-1 films, and(b) PFA-MWNT-2 films on MWNT volume fraction at 10kHz.Insets show best of AC conductivity to percolation theory.
Manufacturing technology
Spray deposition Web coating
Lab-scaleProof of concept
Lab-scaleProof of concept
Intermediate scale Near industrial scale
Industrial collaborators
Web coating – lab unit up and running
Rotatingdrum
Monomerdelivery
Evaporationsource
Sputtercathode
E-beamMelamine +
TiO2-np film?
Conclusions
Nanoparticle-polymer filmsNew process routeExciting propertiesScale up
CNT-polymer filmsReproduced (exceeded?) best results from literatureShows “platform” nature of processOther industrial uses
Mini web coaterFirst good results obtained but need to show reproducibilityMigrate to large web coater in the next year
IeMRC investment effectively geared with other funds