Challenges in Fabricating Llarge-area Metallic Materials for Energy

Report
Challenges in fabricating large-area metallic
materials for energy economy
energy
finished
raw
fabrication
product
material
heat
Paul H. Steen
[email protected]
NSF CMMI Workshop 2011
Atlanta, GA
Chemical & Biomolecular Engineering
Cornell University
energy economy
• 11.9 Quad energy (electrical) consumed USA (2002)
• 26.3 Quad energy losses (2002)
1 Quad = 278,000 GW-h = 278 TW-h
• solar energy at earth’s surface =
1 – 10,000 X energy consumption of all humanity
energy economy – grid losses
1 Quad = 278 TW-h
energy economy – grid losses
electrical
energy
100
distribution
(steel transformer)
heat
68.8
1 Quad = 278 TW-h
distributed
electricity
31.2
metallic glass transformer cores
micro-structure
infrared images
of transformers
crystalline core
amorphous metal core
• 33.8 TW-h energy (electrical) DT losses USA (2004)
• 27.0 TW-h potential savings by Amorphous Metal DT
Source: Metglas sales literature
Metglas – Conway, SC
amorphous core
power- distribution
transformer (DT)
EAS
Source: “PowerSource” Summer 2007
Metglas fabrication
Metglas challenge
• cast new ultra-efficient nano-crystalline alloys
deeper understanding of fundamentals:
high-speed contacting, solidification, transport
example: fundamentals & product quality
surface tension
Contact Zone
Cornell: planar-flow spin-casting
high-speed contacting ‘texture’
5 cm
Air side
Wheel side
Cast direction
C.J. Byrne et al., Capillary puddle vibrations linked to casting-defect formation in
planar-flow melt spinning,
Met. & Mat. Trans. B, 36B, pp. 445-456, 2006
‘origin’ of texture – surface tension vs inertia
surface tension
  

f  U /  1.94
3 
 G 
natural frequency: plucked liquid sphere (Rayleigh oscillation)
C.J. Byrne et al., Capillary puddle vibrations linked to casting-defect formation in
planar-flow melt spinning,
Met. & Mat. Trans. B, 36B, pp. 445-456, 2006
1
2
example: controlling texture
10 cm
0.12 cm
5 cm
0.012 cm
Sharp Edge
Rounded Edge
BL Cox, in preparation
example: manipulating texture
Overhead
Pressure
BN Patterned
Ribbon
5 cm
Contact zone
Ribbon
Write-head
Erase-head
US Patent 7,306,025 2007, “Methods for continuous casting of a molten material”
US Patent 7,082,986 2006, PH Steen “A system . . . for continuous casting . . .”
example: manipulating texture
Lens
Prism
Laser
Byrne, CJ, et al., “In-situ manipulation of cooling rates during planar-flow melt spinning processing,”
Mat. Sci. & Eng. A. 459, 172-181, 2007.
photo-voltaic (PV) cell – the sandwich
‘learning’ curve – grid-parity goal
Source: Surek (2005)
fabrication path
Source: RGS presentation
Oerlikon Solar architecture – thin-film bi-junction
Source: OS Media Conference EU PVSEC 2010 Valencia, Spain 9/7/2010
Oerlikon Solar (OS) – batch fabrication
Step 1
Step 2
Step 3
front glass
TCO +
front glass
Micromorph
+ TCO +
front glass
low-pressure
chemical vapor
deposition (LPCVD)
TCO +
front glass
plasma-enhanced
chemical vapor
deposition (PECVD)
Micromorph +
TCO + front
laser processing
(LSS laser)
Source: http://www.oerlikon.com/solar/
back contact +
Mm + TCO + front
OS ThinFab manufacturing
Source: http://www.oerlikon.com/solar/thinfab/ 9/2010
OS challenges
• market ThinFab, increase efficiency & innovate
• fend-off competing technological alternatives
deeper understanding of fundamentals:
high-speed deposition, laser surface-processing
RGS: alternative fabrication strategy
RGS continuous-casting of Si wafer
RGS challenges
• achieve quality while maintaining productivity
deeper understanding of fundamentals:
high-speed contacting,
polycrystalline seeding and solidification
summary: fabrication science – our challenge!
interfaces
energy
liquid
finished
raw
fabrication
product
material
solid 1
gas
heat
• deeper understanding needed of fundamentals of high-speed
• contacting
• lubrication
• laser-processing
• solidification
• transport
• metrology
Ack: NSF CMMI 07278613; Metglas; RGS; Alcoa

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