Durable Light Management Solutions for Solar Module Efficiency Improvement - 3M, James Ma
Durable Light Management Solutions for Solar Module Efficiency Improvement Sept 2018 James Ma, Mark O’Neill, Joe Eaton, Scott Howard Renewable Solutions Lab, 3M Electrical Market Division, St. Paul, MN 55144 3M at a glance • Sales in ~200 countries • $32 billion in sales • Five business groups • 90,000 3Mers globally • 113,000 patents • One of 30 companies on the Dow Jones Industrial Index IndustrialHealth Care ConsumerSafety & Graphics Electronics & Energy We bring solutions to markets through our business groups 4© 3M 2017. All Rights Reserved. 3M Confidential. Solar Energy Market From factory to field, 3M products help make solar energy more efficient, reliable and affordable – every step of the way. 016. ll t r . fi tial. Crystalline Silicon Light Optimization Rigid Thin Film Power Optimization Concentrated Photovoltaics Module Assembly Flexible Thin Film Agenda • What is 3M Light Redirecting Film (LRF) and how does it work • Performance data of LRF in a module • Demonstrated durability and reliability over time Significant opportunity to increase module efficiency by recapturing unused light Non active area in a typical c-Si PV module % of module area Tabbing ribbons 3.2% Cell separation 3.3% Cell corners 2.0% Outside perimeter 6.8% Total 15.3% backsheet cell glass 3M LRF tabbing ribbon encapsulant encapsulant 3M Light Redirecting Film (LRF) applied over tabbing ribbon Incident light redirected onto active portion of module Key product attributes driving LRF performance Polymeric Film Adhesive 60 Metal-coated Polymeric Microstructure 1. Micro-optical structure design and precision manufacturing 2. Reflectivity of surface 3. Precise registration of film over tabbing ribbon 4. Outdoor durability of materials Key attributes3M LRF Construction How does LRF work? Optical principle of Total Internal Reflection (TIR) inside module nglass = 1.5 nair = 1.0 cell TIR TIR nencapsulant = 1.5 light redirecting film (LRF) Snell’s law i n1 n2 When 𝜃𝑡 = 90 degree, total internal reflection happens n1 ∗ sin𝜃𝑖 = 𝑛2 ∗ sin𝜃𝑡 𝜃𝑖 𝜃𝑡 𝜃𝑐 Light is recycled onto active cell area by LRF 9 QE image at 1040nm 3M LRF is 80% as efficient as cells Measured at NREL Colorado, USA Qu an tu m effi cien cy LRF in a one cell module On a X/Y table • 1040nm diode laser is used • Laser scans across cell/LRF • Quantum efficiency is measured from each scanned spot Test method: Laser Beam Induced Current (LBIC) 10 Power increase prediction confirmed by test results Power increase modeling Measured results show average Pmax increase of 1.5% LRF Module: • 4BB polycrystalline 60 cell module • 2.0mm LRF T80 Base Module: • 4BB polycrystalline 60 cell module • No LRF (exposed ribbons) 2 0.0 1.0 2.0 3.0 4.0 5.0 5.352 0.552 5.652 0.852 5.952 0.162 5.26 2 5 6 . 6 1 . 3 7 3 5 0 2 6 0 . 5 1 . 2 1 6 5 0 M e a n S t D e v N P y t i s n e D ]W[ XAM b epyT 08T esa H lamroN ]W[ XAMP fo margotsi • Optical and electrical modeling predict Pmax gain • Confirmed gain in testing • Baseline polycrystalline 60 cell modules with and without LRF compared • Measured increase shows average gain of 1.5% in Pmax • Consistent result vs. predicted gain from modeling Annualized Energy Performance Solar Position & Tracking Tilt & Orientation Component Dimensions Material Properties 3M Optical Model Outdoor Energy Modeling LRF performance in the field Optimizing LRF for Outdoor Energy Output Instantaneous Power + Independently verified performance increase with LRF -1% 0% 1% 2% 3% Key test requirements: • Samples have statistic gain • Uniform sun irradiation on baseline and LRF modules • Equipment must be linear to sun energy (morning –noon—evening) Field energy testing set up: • Each module has its own load • Each module has its own MPPT tracking • Sampling frequency is 200KHz, avg for each minute • Noise data is filtered out before calculating energy gain • Data collected between 8/15/15 - 11/27/15 Test conducted by TUV Rheinland, Shanghai, China Measu re d f iel d e ne rg y g ain Field energy test results (Baseline N=3, LRF N=3) -1% 0% 1% 2% 3% Pm ax %Ch Flash test results (Baseline N=3, LRF N=3) Average gain: 1.86% Average gain: 1.84% Baseline Modules Baseline Modules 3M LRF Modules 3M LRF Modules Module lab durability and weathering testing results* Out door weathering since Nov. 2012 Test Method Conditions Exposure Results Damp heat 85C, 85% RH 3000 hrs no degradation to LRF observed Thermal cycling 85C -40C 50 & 200 cycles Passed IEC standard Pressure Cooker – PCT 120 °C, 100 %RH, 2 atm 350 hrs no degradation to LRF observed UV exposure (ASTM G155) 3X sun intensity at 40C dry 115 hrs No visible changes Outdoor weathering Minnesota, Arizona, Florida 3 years No visible changes to date *some customers passed 3x IEC requirements Outdoor testing: LRF modules show consistent power output after 3-5 years in the field No reduction in power over time Florida, USA: Hot and Humid ClimateArizona, USA: Hot and Dry Climate Modules measured between 11:00am – 1:00pm each time Modules measured between 11:00am – 1:00pm each time No degradation after 5 years weathering in FL and AZ 1 9 61 4 84 63 52 27 2 6 0 2 5 0 2 4 0 2 3 0 2 2 0 F l w e e k s F L P e a k P o w e r ( W ) L R F M o d u l e s i n F L : 2 0 1 4 t o 2 0 1 8 , 9 e a c h • 3M Light Redirecting Film (LRF) provides a new way to further reduce $/W by increasing module efficiency • Film structure is optimized for both module power and field energy gain • Material selection and 3M processing capabilities deliver precision optical structure Summary Proven power and energy gain Proven durability and weatherability Proven in mass production • More than 20GW modules have integrated LRF into the modules since product launched in late 2016 • LRF modules tested rigorously above and beyond IEC standards • No film degradation has shown over 5 years LRF module outdoor weathering
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