TY - JOUR
T1 - Damp Heat Induced Degradation of Silicon Heterojunction Solar Cells with Cu-Plated Contacts
AU - Karas, Joseph
AU - Sinha, Archana
AU - Buddha, Viswa Sai Pavan
AU - Li, Fang
AU - Moghadam, Farhad
AU - Tamizhmani, Govindasamy
AU - Bowden, Stuart
AU - Augusto, André
N1 - Funding Information:
Manuscript received June 3, 2019; revised August 8, 2019; accepted September 3, 2019. Date of publication October 21, 2019; date of current version December 23, 2019. This work was supported in part by the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (DOE EERE) under Solar Energy Technologies Office (SETO) Agreement 32509 for the Durable Module Materials Consortium (DuraMAT), and in part by the Engineering Research Center Program of the National Science Foundation (NSF) and the DOE EERE under NSF Cooperative Agreement EEC-1041895 (QESST). (Corresponding author: Joseph Karas.) J. Karas, S. Bowden, and A. Augusto are with Solar Power Laboratory, Arizona State University, Tempe, AZ 85281 USA (e-mail: joseph.f.karas@asu. edu; sgbowden@asu.edu; augusto@asu.edu).
Publisher Copyright:
© 2019 IEEE.
PY - 2020/1
Y1 - 2020/1
N2 - Damp heat exposure is one of the most stringent environments for testing the durability of solar cells in packaged modules. Damp heat stresses and induces a variety of degradation modes in solar cells and modules: for example, moisture-induced corrosion of electrodes and interconnections, deterioration of polymeric materials, and/or thermally activated diffusion processes. To screen for these and other potential degradation modes, we subject one-cell modules containing silicon heterojunction (SHJ) solar cells with Cu-plated contacts to extended damp heat tests at 85 °C/85% relative humidity. SHJ cells were laminated with two common encapsulants: ethylene vinyl acetate (EVA) and polyolefin elastomer (POE), and two constructions: glass-backsheet and glass-glass. We observe degradation in all components of solar cell maximum power (PMP): current, voltage, and fill factor, and find evidence of increased carrier recombination and nonideal diode behavior with increasing stress. For glass-backsheet constructions, EVA samples generally degrade more than POE by a factor of approximately 1.5× PMP, and the different encapsulants produce different degradation patterns. Similar trends are observed in glass-glass modules, but to a lesser degree. In a different experiment, we observe a decrease in effective minority carrier lifetime of nonmetallized SHJ precursors measured after damp heat. This implies that some degradation unrelated to the contacts is to be expected and confirms the observation of increasing recombination.
AB - Damp heat exposure is one of the most stringent environments for testing the durability of solar cells in packaged modules. Damp heat stresses and induces a variety of degradation modes in solar cells and modules: for example, moisture-induced corrosion of electrodes and interconnections, deterioration of polymeric materials, and/or thermally activated diffusion processes. To screen for these and other potential degradation modes, we subject one-cell modules containing silicon heterojunction (SHJ) solar cells with Cu-plated contacts to extended damp heat tests at 85 °C/85% relative humidity. SHJ cells were laminated with two common encapsulants: ethylene vinyl acetate (EVA) and polyolefin elastomer (POE), and two constructions: glass-backsheet and glass-glass. We observe degradation in all components of solar cell maximum power (PMP): current, voltage, and fill factor, and find evidence of increased carrier recombination and nonideal diode behavior with increasing stress. For glass-backsheet constructions, EVA samples generally degrade more than POE by a factor of approximately 1.5× PMP, and the different encapsulants produce different degradation patterns. Similar trends are observed in glass-glass modules, but to a lesser degree. In a different experiment, we observe a decrease in effective minority carrier lifetime of nonmetallized SHJ precursors measured after damp heat. This implies that some degradation unrelated to the contacts is to be expected and confirms the observation of increasing recombination.
KW - Copper (Cu) plated contacts
KW - damp heat (DH)
KW - encapsulant
KW - fill factor (FF)
KW - reliability
KW - silicon heterojunction (SHJ)
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U2 - 10.1109/JPHOTOV.2019.2941693
DO - 10.1109/JPHOTOV.2019.2941693
M3 - Article
AN - SCOPUS:85077181876
SN - 2156-3381
VL - 10
SP - 153
EP - 158
JO - IEEE Journal of Photovoltaics
JF - IEEE Journal of Photovoltaics
IS - 1
M1 - 8878168
ER -