Quality of solar modules and module certification November 5th, Poona, India

Dr.-Ing. Jürgen ArpPI Photovoltaik-Institut Berlin AGPhotovoltaic module technologyTesting | Consulting | Research

Photovoltaik-Institut Berlin AG

Senior Consultants und Board of Directors:

Dr.-Ing. Jürgen Arp, Engineer-Economist in mechanical engineeringExperience: Technical University Berlin, Sputnik Engineering Inverters,

Abastrial Solar Consulting Berlin

Dr. rer. nat. Paul Grunow, PhysicistExperience: Founder of Solon AG, Q-Cells AG

Prof. Dr.-Ing. Stefan Krauter, Electrical Engineer Experience: Professor at TU Berlin and UFRJ/UECE Brazil,

Director of Rio Solar Ltd., LAREF, RIO 02/3/5/6

Dipl.-Ing. Sven Lehmann, Electrical Engineer Experience : Energiebiss, Solon AG,

SolarExperts Berlin

Head of supervisory board: Prof. Dr. Rolf Hanitsch (TU, EE)

Testing of Solar Modules

- The basic principles of testing solar modules have been definedat the JRC/Ispra under the dirction of Dr. Heinz Ossenbrink- The target was to simulate 20 yrs. lifetime under the climatic conditions of Europe.- The work of Dr. Ossenbrink founds its way into the standard IEC61215 and IEC 61646.

- TÜV Rheinland and the Arizona State University build up testing facilities more than 10 years ago and collected know how over a long periode of time.- Other institutes like PI Berlin, ISET/Kassel and Fraunhofer Institute/Freiburg established PV labs. So there is a wide variety of experienced labs and institutes in Germany.

Failure rate comparison of crystalline silicon modules for the 1997-2005 and 2005-2007 periods.

G. Tamizh-Mani, et al., Failure Analysis of design qualification testing 2007 vs. 2005, 33rd PVSC Conference, San Diego 2008

Conclusion: significantly rising failure rates of waferbased modules

Failure rate comparison of thin-film modules for the 1997-2005 and 2005-2007 periods.

G. Tamizh-Mani, et al., Failure Analysis of design qualification testing 2007 vs. 2005, 33rd PVSC Conference, San Diego 2008

Conclusion: significantly rising failure rates of thin film modules

DH Test

The Damp-Heat Test is the most critical test for both, waferbased and thin film modules.

It covers a broad variety of issues.

The DH test gives us good information about the core competence of a solar module manufacturer.

Today we focus on the other issues, which could be avoided easlily by focussing on a better quality control.

Special issues and testing methodes of thin-film modules

Wet leakage test shows high rates of failure.

Sensitivity concerning TCO-corrosion

Wet leakage test- Module is covered with water.

- 500V or max. system voltage is applied.

- Isolation resistance times module area >= 40 MΩm²

Conclusion: Inline testing is recommendable, but the dry isolation test is more suitable for production purpose.

TCO corrosion

• one of the most critical issues of thin-film modules in the past

• well understood since a few years• critical products are still on the market and sometimes

even in developement.

TCO corrosion (2)

Wafer based modules• Larger currents and problems with heat dissipation

cause problems with diodes.

• The TC 200 test causes stress to solder points and to cells with preexisting damage. Rising failures of both, thin-film and wafer based modules, show, that we face both issues.

Diode testing according to IEC 61215

Test according to IEC 61215:

- module is exposed to 75°C ambiend temperatur and the diodes with the short circuit current for one hour.- measurement of the temperature of the bypass diodes and calculation of the temperatures inside of them

- increase the current by factor 1,25 for another hour.- check, if diode is still operational.

Diodes (2)

TC 200 testTest procedure:- 200 cyles between -40°C and 85°C.- modules are exposed to MPP current.- typically 6 cycles a day.- roughly one month testing time.

The thermal expansion coefficients of the materials differ in a wide range.αglas = 4,5-7αsilicon = 2αpolyester = 80

TC 200 test (2)

Waferbased module initial EL picture and after TC 200

TC 200 (3)

Recommendation: Inline electroluminescence and/or periodical EL inspection of the whole supply chain

Conclusion

1. A solar module build in the traditional way by an experienced manufacturer can achieve a lifetime of 25 years and longer (as the ones on our roof).

2. The experience of the testing labs is, that the large number of new manufacturers led to an decrease of of quality.

3. The customer can either stick to experienced manufacturers or build up an effective quality control.

Thank you!