SLIDE 1
- X. Zhao, A.G. Cook, H. Assender, C. Johnston, M. Johnson1 and
Patrick 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
SLIDE 2
Outline
The more electric airframe Power capacitors Nanocomposite dielectrics Progress Conclusions and future directions
SLIDE 3 Rudder Elevators Loads
Load Generator Power control Load centre Transmission Transmission& Distribution
Galleys Avionics TE flaps Spoilers Ailerons Gear Loads Lights Loads Cabin services ECS compressor Loads Lights APU generator power converter Fuel pump 250kW generator LE flaps Lights Anti-ice Loads 250kW generator
More electric aircraft
Features
Electrical starting Electro-hydraulic actuators / Electro-mechanical actuators Electrical anti-ice Modified cabin environmental system Simplified engine-airframe interface
Deleting
Three major hydraulic systems Ram-air turbine Cabin-air bleeds Pneumatic anti-ice
ECS compressor
SLIDE 4 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
SLIDE 5
Power capacitors
Increased electrical power generation – 1MW Increased power conditioning Current high value capacitors based on electrolytics or polymer films Heavy (~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
SLIDE 6
Nanocomposite dielectric materials
Ceramic particles in polymers Add nanoparticles to increase dielectric constant to 30-50 (C α ε) But Thin films (C α 1/t) Do not undermine breakdown strength (u α E2) Do not compromise processability into large areas Do not increase density more than necessary Properties up to 200ºC Develop a scaleable manufacturing technology
SLIDE 7
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.
SLIDE 8 Manufacturing technology
Spray deposition Web coating
Lab-scale Proof of concept Lab-scale Proof of concept Intermediate scale Near industrial scale
Industrial collaborators
SLIDE 9 Manufacturing technology
Pre- heated table Syringe pumps with nano suspensions Hypodermic needle(s) Compressed air X-Y manipulator linear drives
Sputter cathode Evaporation E-beam Monomer delivery Rotating drum Roll-to-roll
SLIDE 10 Spray deposition
Spray nozzle Compressed air Hypodermic needle TPGDA/BaTiO3/MEK:EtOH suspension Syringe Syringe pump Atomized droplet spray x y Pre-metallized glass substrate Heated plate moving in x-y Spray nozzle Compressed air Hypodermic needle TPGDA/BaTiO3/MEK:EtOH suspension Syringe Syringe pump Atomized droplet spray x y Pre-metallized glass substrate Heated plate moving in x-y
SLIDE 11
Acrylate-BaTiO3 films
SEM micrograph of PTPGDA-30vol%BaTiO3 film at an accelerating voltage of 2.0 kV.
SLIDE 12
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.
SLIDE 13 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.
SLIDE 14
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.
SLIDE 15
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.
SLIDE 16 Manufacturing technology
Spray deposition Web coating
Lab-scale Proof of concept Lab-scale Proof of concept Intermediate scale Near industrial scale
Industrial collaborators
SLIDE 17
Web coating – lab unit up and running
Rotating drum Monomer delivery Evaporation source Sputter cathode E-beam Melamine + TiO2-np film?
SLIDE 18
Conclusions
Nanoparticle-polymer films
New process route Exciting properties Scale up
CNT-polymer films
Reproduced (exceeded?) best results from literature Shows “platform” nature of process Other industrial uses
Mini web coater
First good results obtained but need to show reproducibility Migrate to large web coater in the next year
IeMRC investment effectively geared with other funds
