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Evolution of cell cracks in PV ‐modules under field and laboratory conditions
Author(s) -
Buerhop Claudia,
Wirsching Sven,
Bemm Andreas,
Pickel Tobias,
Hohmann Philipp,
Nieß Monika,
Vodermayer Christian,
Huber Alexander,
Glück Bernhard,
Mergheim Julia,
Camus Christian,
Hauch Jens,
Brabec Christoph J.
Publication year - 2018
Publication title -
progress in photovoltaics: research and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.286
H-Index - 131
eISSN - 1099-159X
pISSN - 1062-7995
DOI - 10.1002/pip.2975
Subject(s) - snow , photovoltaic system , materials science , stress (linguistics) , environmental science , accelerated aging , structural engineering , reliability engineering , automotive engineering , electrical engineering , engineering , composite material , meteorology , physics , linguistics , philosophy
Abstract Damaged modules, especially with cell cracks, can be observed quite often in photovoltaic‐installations. Little knowledge exists about long‐term stability of precracked modules at real operating conditions. Previous investigations and existing standards focus on the degradation of new, defect‐free modules. This work highlights a twofold approach for life‐time study of precracked modules: (1) outdoor exposure of 54 precracked modules for 1 year and (2) artificial stressing of 20 representative precracked modules with a novel load test setup simulating snow and wind loads. The outdoor exposure reveals that at moderate weather conditions, no changes were detectable, neither in electric performance nor in EL‐images. However, the accelerated static load tests with stepwise increasing pressures point out that above a certain threshold, cracks grow. Below this threshold, formerly unseen cracks become visible at the loaded stage. In addition, modules with a smaller number of damaged cells have a stronger tendency to degrade further than modules with an already large number of cracked cells. Remarkably, the power output measured with a solar simulator after a stress test up to 2500 Pa (describing conservative proof conditions for severe snow loads according IEC 61215) remains unchanged for almost all modules.