TÜV Rheinland Japan Photovoltaic Department Kengo Morita TÜV Rheinland Japan Ltd. Solar Energy Assessment Center (SEAC) Chigasaki-higashi, Tsuzuki-ku, Yokohama , Japan Tel: Direct: Fax: Performance evaluation technology of photovoltaics for certification & calibration No part of this presentation may be reproduced in any form or by any means without the permission from TÜV Rheinland Japan - Photovoltaic Department.

TÜV Rheinland Japan Photovoltaic Department * About us * Importance of performance evaluation * General concept for performance evaluation of PV modules * Our facilities for the performance measurement * Measurement technique of - Single amorphous - Multi junction (ex; a-Si / μc-Si) - CIS * Future Plan Outline

TÜV Rheinland Japan Photovoltaic Department About Us Established as a pressure vessel inspection organization we have been offering international safety and system management certification for over 130 years. Environment People Technology

TÜV Rheinland Japan Photovoltaic Department Automotive Industry Construction & Real Estate Health Aviation and Airports Energy Industry Leisure Time Industry Primary Industry Capital Goods Suppliers Banks & Insurance Companies Consumer Goods Industry Railway/Track-Based Systems Industries served by the TÜV Rheinland Group

TÜV Rheinland Japan Photovoltaic Department Our activity in PV field - PV module certification program *IEC and IEC – Crystalline *IEC and IEC – Thin Film *Factory inspection - Calibration & Measurement Services of Photovoltaics - Type approval of PV module components Accreditations Our testing laboratory conforms to ISO/IEC 17025: IECEE CB Accreditation - JNLA & ASNITE Accreditation by IA Japan - DATech Accreditation by DAR (Germany)

TÜV Rheinland Japan Photovoltaic Department Opened in Yokohama city on 2009/6/15 SEAC (Solar Energy Assessment Center) The SEAC provides evaluations of the Thin Film Modules and Calibration Services.

TÜV Rheinland Japan Photovoltaic Department Importance of performance evaluation Simplified test sequence of certification program (IEC61215, 61646) Light-soaking  only IEC Visual inspection, power determination, insulation test (dry and wet) Thermal cycling (TC200) Electr. properties Outdoor exposure Bypass- diode test Hot-spot test UV preconditioning Thermal cycling (TC50) Humidity freeze test Robustness of terminations Damp heat test Hail impact Mech. load test Visual inspection, power determination, insulation test (dry and wet)

TÜV Rheinland Japan Photovoltaic Department Importance of performance evaluation Certification testing Simplified pass criteria regarding performance - For crystalline Si (IEC61215) * Degradation rate of each test < 5% * Degradation rate of each sequence < 8% - For thin-film (IEC61646) * P max at STC after light soaking > 90% of P max of min_value specified by manufacturer Calibraton testing Measured module is used as reference module for measurement control of production line

TÜV Rheinland Japan Photovoltaic Department General concept for performance evaluation 1. Relevant standards * IEC (IV measurement method) * IEC (Reference cell & module with calibration method) * IEC (Measurement principles with reference spectral irradiance data) * IEC (Traceability) * IEC (Computation of the spectral mismatch correction) * IEC (spectral response measurement method) * IEC (Requirement of solar simulator)

TÜV Rheinland Japan Photovoltaic Department General concept for performance evaluation 2. Standard test condition (STC) * Irradiance: 1kW/m 2 * Spectral irradiance distribution: AM1.5 G, Reference spectrum * Temperature: 25 ℃ Reference spectral irradiance (AM1.5G) Reference spectral irradiance is determined by IEC The performance of photovoltaics should be measured based on standard test condition.

TÜV Rheinland Japan Photovoltaic Department Photograph of reference solar cell Spectral response of some kind of general photovoltaics The spectral response of reference solar cell should be similar to tested sample. Otherwise spectral mismatch error is induced. General concept for performance evaluation 3. Reference solar cells

TÜV Rheinland Japan Photovoltaic Department What is spectral mismatch error ? (IEC : Computation of the spectral mismatch correction for muasurement of photovoltaic devices) Φ S (λ) ： Reference spectral irradiance Φ ｍ (λ) ： Spectral irradiance of used solar simulator Q １ (λ) ： Spectral response of reference solar cell Q ２ (λ) ： Spectral response of tested sample General concept for performance evaluation 4. Spectral mismatch evaluation

TÜV Rheinland Japan Photovoltaic Department Our facilities for performance evaluation 1. Photo of solar simulator Long pulse solar simulator (LPSS)

TÜV Rheinland Japan Photovoltaic Department Our facilities for performance evaluation 2. Specification of LPSS ・ Available test area: 2.0×1.4m ・ Class AAA in accordance with IEC Ed.2 - Spectral irradiance: Air Mass 1.5G, Variable type <±25% according to IEC Non-Uniformity: <±2.0% (Class A) - Stability of Pulse: within ±2.0% ・ Maximum pulse duration: 800msec ・ Lamp: 6 Xenon short-arc lamp (5kW) ・ Accuracy of current & voltage measurement: <±0.2%

TÜV Rheinland Japan Photovoltaic Department Check every month Our facilities for performance evaluation 3. Measurement data of Non-Uniformity (%)

TÜV Rheinland Japan Photovoltaic Department Match to crystalline Si (IEC/JIS) Match to amorphous Si (JIS) Check every month Our facilities for performance evaluation 4. Measurement data of Spectral match Spectral irradiance of solar simulator

TÜV Rheinland Japan Photovoltaic Department Irradiance during 1 pulse (Measured Isc / calibrated Isc) Sample Isc after irradiance correction (Sample Isc / measured irradiance by reference range) LTI = ±0.9% Accuracy of irradiance correction = ±0.1% (This is the concept of STI) Our facilities for performance evaluation 5. Measurement data of Temporal instability

TÜV Rheinland Japan Photovoltaic Department Our facilities for performance evaluation 6. Measurement procedure 1. Check of spectral response of the tested sample to be measured 2. Spectral mismatch evaluation (IEC ) 3. Set of the tested sample and reference cell (Reference cell should be set at the position of average irradiance in the area of tested sample.) 4. Temperature control (tested sample and reference cell) 5. Check of sweep direciton and sampling speed 6. Adjustment of irradiance 7. Measurement of current and voltage of the tested sample & irradiance (current of reference cell) at same time during sweeping voltage, 250point, repeat time: 3) 8. Data analysis

TÜV Rheinland Japan Photovoltaic Department Our facilities for performance evaluation 7. Uncertainty Isc: 2.0% Voc:1.1% Pmax:2.3% (coverage factor k = 2)

TÜV Rheinland Japan Photovoltaic Department Pmax: 0.6% (2σ ） Isc: 0.2% (2σ ） Sample: mono-crystalline Si, 1.6×1.0m Our facilities for performance evaluation 8. Measurement Reproducibility of Pmax, Isc by our measurement system during 6 months

TÜV Rheinland Japan Photovoltaic Department Example of Test Report of IV measurement

TÜV Rheinland Japan Photovoltaic Department S. Rummel et al., 2006 IEEE 4th World Conference on Photovoltaic Energy Conversion (WCPEC-4) held May 7-12, 2006 in Waikoloa, Hawaii Measurement technique for thin-film type Results from the Second International Module Inter-comparison

TÜV Rheinland Japan Photovoltaic Department Reference solar cell: Pseudo amorphous reference cell Spectral mismatch evaluation Structure: Crystalline Si with optical filter which spectral response is similar to tested amorphous cell) Additional filter typeIdentification typeencapsulated type 1. single amorphous Measurement technique for thin-film type

TÜV Rheinland Japan Photovoltaic Department Light angle characteristics of reference cells 1. single amorphous Measurement technique for thin-film type Solar simulator Incident light Reflection light lens Ref Cell Re-reflection Irradiance measurement error is induced by multi- reflection. One of solution is structure of reference cell.

TÜV Rheinland Japan Photovoltaic Department Spectral response of top cell and bottom cell of multi (double) junction cell ・ Double junction consists of top cell (ex:a-Si) and bottom cell (ex:thin film c-Si) with difference range of spectral response ・ Series connected structure (Top+Bottom) Measurement technique for thin-film type 2. Multi-junction

TÜV Rheinland Japan Photovoltaic Department IV characteristic of the module strongly depends on the spectral irradiance distribution of the light source. The current of the module is limited to the current of the cell with the lower Isc (Top or Bottom) It is more difficult to evaluate STC performance than that of single junction cell Tandem modules are series connected structure Measurement technique for thin-film type 2. Multi-junction

TÜV Rheinland Japan Photovoltaic Department Measurement technique for thin-film type 2. Multi-junction Spectral dependence characteristics of multi-junction cell IV characteristic of the multi-junction cell strongly depends on the spectral irradiance distribution of the light source. Source: Fraunhofer ISE

TÜV Rheinland Japan Photovoltaic Department Measurement technique for thin-film type 2. Multi-junction 1. Measure spectral response of top and bottom cell (tested sample) 2. Make 2 reference component cells used by stable crystalline Si cell with proper optical filter based on spectral response data of tested sample. 3. Measure spectral response of 2 reference component cells 4. Confirm that these reference cells are relatively equivalent to that of tested sample (Spectral mismatch evaluations) 5. Calibrate each reference cell in accordance with IEC Measure IV characteristic of tested sample at the condition that irradiance level measured with each reference component cell is 1 Sun (kw/m 2 ) (This condition is equivalent to AM1.5G for double-junction) Measurement procedure for double-junction

TÜV Rheinland Japan Photovoltaic Department Measurement technique for thin-film type 3. CIS Spectral response of CIS and crystalline-Si Reference solar cell: Crystalline-Si Need spectral mismatch correction

TÜV Rheinland Japan Photovoltaic Department Measurement technique for thin-film type 3. CIS Light soaking effect, annealing effect of CIS solar cell Preconditioning should be determined before performance measurement

TÜV Rheinland Japan Photovoltaic Department Future plan - Calibration of secondary reference cell & module - Research for Performance evaluation method * Proper structure of reference device for amorphous & multi-junction * Spectral adjustment technique for multi-junction * Proper preconditioning for CIS * New method for new technology (DSC, Organic cell) * Traceability to production line - Research for Reliability evaluation method * Long-term outdoor exposure test * Correlation between Lab test and outdoor test * Acceleration test

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