Kengo Morita T Ü V Rheinland Japan Ltd. Solar Energy Assessment Center (SEAC) 4-5-24 Chigasaki-higashi, Tsuzuki-ku, Y

1. Performance evaluation technology of photovoltaics for certification & calibration Kengo Morita TÜV Rheinland Japan Ltd.Solar Energy Assessment Center (SEAC) 4-5-24 Chigasaki-higashi, Tsuzuki-ku, Yokohama 224-0033, Japan Tel: +81-45-271-3508 Direct: +81-45-914-0439 Fax: +81-45-271-3525 email: kengo.morita@jpn.tuv.comhttp://www.tuv.com No part of this presentation may be reproduced in any form or by any means without the permission fromTÜV Rheinland Japan - Photovoltaic Department. TÜV Rheinland Japan Photovoltaic Department

2. Outline • * 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 TÜV Rheinland Japan Photovoltaic Department

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

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

5. Our activity in PV field - PV module certification program *IEC 61215 and IEC 61730 – Crystalline *IEC 61646 and IEC 61730 – Thin Film *Factory inspection - Calibration & Measurement Services of Photovoltaics - Type approval of PV module components Accreditations Our testing laboratory conforms to ISO/IEC 17025:2005 - IECEE CB Accreditation - JNLA & ASNITE Accreditation by IA Japan - DATech Accreditation by DAR (Germany) TÜV Rheinland Japan Photovoltaic Department

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

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

8. 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) * Pmax at STC after light soaking > 90% of Pmax 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

9. General concept for performance evaluation 1. Relevant standards • * IEC60904-1 (IV measurement method) • * IEC60904-2 (Reference cell & module • with calibration method) • * IEC60904-3 (Measurement principles • with reference spectral irradiance data) • * IEC60904-4 (Traceability) * IEC60904-7 (Computation of the spectral mismatch correction) * IEC60904-8 (spectral response measurement method) * IEC60904-9 (Requirement of solar simulator) TÜV Rheinland Japan Photovoltaic Department

10. General concept for performance evaluation 2. Standard test condition (STC) • * Irradiance: 1kW/m2 • * Spectral irradiance • distribution: AM1.5 G, • Reference spectrum * Temperature: 25℃ Reference spectral irradiance (AM1.5G) Reference spectral irradiance is determined by IEC60904-3. The performance of photovoltaics should be measured based on standard test condition. TÜV Rheinland Japan Photovoltaic Department

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

12. General concept for performance evaluation 4. Spectral mismatch evaluation What is spectral mismatch error ? ΦS (λ) ：Reference spectral irradiance Φｍ (λ) ：Spectral irradiance of used solar simulator Q１(λ) ：Spectral response of reference solar cell Q２(λ)：Spectral response of tested sample (IEC60904-7: Computation of the spectral mismatch correction for muasurement of photovoltaic devices) TÜV Rheinland Japan Photovoltaic Department

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

14. Our facilities for performance evaluation 2. Specification of LPSS ・ Available test area: 2.0×1.4m ・ Class AAA in accordance with IEC60904-9 Ed.2 - Spectral irradiance: Air Mass 1.5G, Variable type <±25% according to IEC60904-9 - 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

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

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

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

18. Our facilities for performance evaluation 6. Measurement procedure 1. Check of spectral response of the tested sample to be measured 2. Spectral mismatch evaluation (IEC60904-7) 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

19. 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

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

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

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

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

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

25. Measurement technique for thin-film type2. Multi-junction ・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) Spectral response of top cell and bottom cell of multi (double) junction cell TÜV Rheinland Japan Photovoltaic Department

26. Measurement technique for thin-film type2. Multi-junction Tandem modules are series connected structure The current of the module is limited to the current of the cell with the lower Isc (Top or Bottom) IV characteristic of the module strongly depends on the spectral irradiance distribution of the light source. It is more difficult to evaluate STC performance than that of single junction cell TÜV Rheinland Japan Photovoltaic Department

27. Measurement technique for thin-film type2. 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

28. Measurement technique for thin-film type2. Multi-junction Measurement procedure for double-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 IEC60904-2 6. Measure IV characteristic of tested sample at the condition that irradiance level measured with each reference component cell is 1 Sun (kw/m2) (This condition is equivalent to AM1.5G for double-junction) TÜV Rheinland Japan Photovoltaic Department

29. Measurement technique for thin-film type3. CIS Spectral response of CIS and crystalline-Si Reference solar cell: Crystalline-SiNeed spectral mismatch correction http://www.showashell-solar.co.jp/index.html TÜV Rheinland Japan Photovoltaic Department

30. Measurement technique for thin-film type3. CIS Light soaking effect, annealing effect of CIS solar cell Preconditioning should be determined before performance measurement http://www.tech.nedo.go.jp/ TÜV Rheinland Japan Photovoltaic Department

31. 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 TÜV Rheinland Japan Photovoltaic Department

32. TÜV Rheinland - Precisely Right We AdviseDevelopFacilitateTestCertify Thank you for your attention TÜV Rheinland Japan Photovoltaic Department