Laser Concepts for Industrial Thin Film PV Production Michael Haase Nachname Carl BaaselVorname Lasertechnik GmbH & Co. KG Position Starnberg / Günding Starnberg 06. September 2006 January, 27th. - 28th. 2009 1
Contents of presentation Short presentation Rofin Overview photovoltaic technologies Laser processes in photovoltaic application Laser concepts for laser manufacturing in photovoltaic industry Examples for application in photovoltaic industry Summary 2
ROFIN Global Where we are? World wide > 1.750 ROFIN employees 17 facilities in Asia, North America und Europe Service organisations in 50 countries More than 3.000 customers world wide 112 sales engineers and 315 employees for service and support Regional und industrial specialized employees for customer support More than 31.000 installed laser systems 4.000 Lasers FY 2008 Turn over in FY 2008 575 Mio. US$ 3
ROFIN Industrial processes for photovoltaic Macro... Micro... Marking... Cutting Micro welding Marking of metalls Welding Micro cutting Marking of plastics Surface treatment Mirco structuring Marking of solar cells Micro drilling Day & Night Design Ablation Perforating Plastic welding Glass cutting 4 Label marking SmartCard marking Marking of semi conductors
Photovoltaic Technologies Mono crystalline Silicon Ingot Silicon solar cell Mono crystalline wafer Mono crystalline solar cell Mono crystalline solar module Solar cell produced by -> monocrystalline -> polycrystalline Silicon Solar power plant silicon (thickness < 200µm) Poly crystalline Silicon Ingot Poly crystalline wafer Poly crystalline solar cell Poly crystalline solar module Source: Trinasolar Thin film solar cell Solar cell made by µm thin absorber films: -> a-si, µ-si -> Copper-Induim-Gallium-Selenide -> Copper-Indium-Sulfide -> Cadmium Telluride 5 Front glass Front contact: TCO Absorber film: xsi/cdte/cis/cigs Rear contakt: Me PVB foil Rear glass Source: Signet Solar
Laser - Material Interaction Interaction between Laser - Material electronstimulation moleculeoscillation UV interaction WW mit between Elektronen electrons plasma Plasmabildung Plasma evaporation Verdampfung (Photochemisch: Photochemisch photochemical Dissoziation Dissoziation) dissociation VIS VIS gridoscillation NIR Transparenz Transparenz interaction between WW mit Elektronen electrons non nichtlineare linear effects Effekte Lawinenionisierung self ionisation Selbstfokussierung self focussing Multiphotonenabsorption multi photon absorption Plasmaanregung plasm stimulataion P1 P0 NIR IR interaction Wechselwirkung between mitmit Molekülen Ionen molecules melting Schmelzen sublimation Sublimation: Lambert Beer P1=P0*e-ε*l P0=input power P1=output power Prinzipkurve Duran, D=2mm UV Laser 6 ε=absorbtion coefficient NIR Laser IR Laser l=material thickness
Laser - Material Interaction Desorption melting by highörtlich pressure of gaseous material out ot high Austrieb derofschmelze durch hohen Gasdruck des dampu 8 2 energy input per unit of area (>10 W/cm ) fförmigen Materials bedingt durch hohen Energieeintrag pro Flächen- bzw. Volumeneinheit (>108 W/cm2) Laser Melting Process direction Plasma, evaporated material Silicon 7 Rofin
Laser - Material Interaction High pulse Hohe Pulsenergie energy pro per Flächeneinheit unit of area transfers überführt the material das Material directly direkt into inthe die vapour Dampfphase phase and undremove löst das the Funktionsmaterial thin film material unter from the hohem substrate Druck by an high der pressure. Grenzschicht vom Trägermaterial. Laser Thin film: TCO, Si, Me Glass Rofin Laser 8
Laser concepts for thin-film photovoltaic Endpumped (longitudinal) solid state lasers Outcoupling mirror Pumping diode Nd:YAG/Vanadate rod Laser beam Fiber Mirror Pulse duration: 10-100 ns Pulse frequency: 50-200 khz Wavelength: TEM00 1064 nm TEM00 532 nm TEM00 355 nm 9 high repetition rate (> 100 khz) high p-to-p stability (<1.5%@100kHz) small footprint (600x30x220 -> l-w-h) fequency conversion possible limited output power (up to 20W)
Laser concepts for thin-film photovoltaic Side pumped (transversal) solid state lasers Cooling Power supply Pumping diodes Resonator mirror Nd:YAG-rod Laser beam Mirror Pulse duration: 50-500 ns Pulse frequency: < 100 khz Power: up to 1000 W multimode Wavelength: TEM00 1064 nm TEM00 532 nm 10 Outcoupling mirror high average output power (up to 1kW) high pulse energy (75mJ@6kHz) poor p-to-p stability by high repetition rates (3%@6Hz) limited beam quality larger footprint (1700x1200x1800mm -> l-w-h)
Laser concepts for thin-film photovoltaic Diode pumped Fiber laser PumpingDiodes Signal incoupling Multimodelaserdiodes multimodecombiner Pulse duration: > 50 ns Pulse frequency: up to 100 khz Power: up to kw Multimode Wavelength: 1055-1090 nm 11 Cladding pumped LMA fiber SM laser outcoupling very small footprint easy integration by fiber coupling limited peakpower 532 nm und 355 nm not available
Rofin The open minded Consultant One supplier for all PV laser technologies 12
Laser applications for thin-film photovoltaic Edge deletion Scribing Glass cuting Patterning Marking 13
Example of laser application for photovoltaic Scribing of coatings for thin film solar cells High precision of isolation scribes (50 µm width und distance between) garantees optimum efficiency for the thin film solar cell Cutting speed 1000... 2000 mm/s Width of scribe < 40 µm q-switched Nd:Vanadate laser Rofin Conductive layer Absorber Conductive layer Glass Isolation cut by using laser w<40 µm 14
Example of laser application for photovoltaic Selective removal of thin film layers with ps lasers 38 µm 330 nm Mo Scribe on glass (Width: 38 µm, depth: 330 nm) 15 Power: 20W @ 4 MHz (measured at the target) Pulse energy: 5µJ max (measured at the target) Pulse duration: 10-30ps Repetition rate: 1 4 MHz Beam quality: M2 < 1.5
Example of laser application for photovoltaic Edge deletion of thin film solar cells by using solid state lasers Process time < 20sec/modul (1,100x1.300x12mm² ) diode pumped q-switched Nd:YAG laser with fibercoupling und scanner Highest removal rates up to 50cm²/s without damaging the glass surface for optimum lamination and electrical functionality of thin film solar modules 16
Example of laser application for photovoltaic Cutting of thin film glass substrates by using solid state lasers Cutting of solar substrates by using lasers leads to best edge quality without mechanical damages for high bending stability of the solar modules 17 H2B Photonics
Application - glass cutting by using lasers Laser Glass Cutting leads to high bending stability Strength Test Conventional: without laser Glas cutting with laser Source: MDI Schott 18
Example of laser application for photovoltaic Marking of Solar cells Rofin TCO marking for a thin film solar cell Speed of marking >100mm/s Process time < 5s q-switched Nd:Vanadate laser Individual marking of solar cells helps to optimise the production of solar cells for cost reduction 19
Summary of presentation The right laser concept leads to highly productive processes with optimal quality of the solar cells Laser processes for the photovoltaic leads to soft material manufacturing with highest precision und performance of production Laser processes increases the efficiency of solar cells and decreases costs of production for a sunny future of the solar industry 20
Let s share the success Thank you Thank you! 21 Michael Haase Phone: +49 5187 300109 Mobil: +49 160 95931834 michael.haase@baasel.de www.rofin.com