Material and Method
Introduction
Results and Discussion
Conclusions
H. Nagasaki1, T. Itayama1, K. Iwami1, C. Yamamoto2, Y. Hara2, A. Masuda2 and N. Umeda1
1. Tokyo University of Agriculture and Technology, Japan
2. National Institute of Advanced Industrial Science and Technology, Japan
Developing an acetic acid detection sensor for
photovoltaic modules using a pH-sensitive fluorescent dye
◆Main factor of photovoltaic (PV) module degradation
Electrode corrosion by acetic acid that generated from
ethylene vinyl acetate copolymer [1].
Non-destructive measurement of acetic acid distribution
in PV module during a damp heat test
◆Detection method of acetic acid in PV module
Methods Feature
Ion chromatography Destructive, Quantitative [2]
Infrared spectroscopy Non-destructive, Qualitative [3]
Raman spectroscopy Non-destructive, Qualitative [4]
Non-destructive and Quantitative detection method of
acetic acid in PV module has not been established.
[1] C. Peike et al., Solar Energy Materials & Solar Cells, vol. 116, pp. 49-54 (2013).
[2] A. Masuda et al., Japanese Journal of Applied Physics, vol. 54, 04DR04 (2015).
[3] E. Wang et al., Energy Procedia, vol. 33, pp. 256-264 (2013).
[4] C. Peike et al., Solar Energy Materials & Solar Cells, vol. 95, pp. 1686-1693 (2011).
[5] T. Asaka et al., Japanese Journal of Applied Physics, vol. 53, 04ER18 (2014).
[6] T. Asaka et al., Japanese Journal of Applied Physics, vol. 54, 08KG07 (2015).
References
Proposed method: Acetic acid detection using pH-sensitive fluorescent dye [5, 6]
◆pH-sensitive fluorescent dye ◆Sensor fabrication
◆EL images
◆Test PV module structure
SNARF-4F, Thermo Fisher Scientific Inc.
λex: 532 nm , λem: 587 nm and 650 nm
Intensity ratio of two fluorescent wavelength depends on
pH value.
587 nm
650 nm pH 8.01
pH 6.99
pH 5.99
pH 5.00
Fluorescent Intensity Ratio (FIR)
FIR = I587 / I650
pH dependence
Degradation due to high-temperature and
high-humidity environment.
Non-destructive and temporal detection of acetic acid in PV module
during DH test was successfully demonstrated.
Generation rate of acetic acid near the edge part was lager than that
near the central part.
Acetic acid concentration was not distributed uniformly over the PV
module.
Acetic acid generation
pH change
Fluorescent wavelength
change
◆Damp Heat (DH) Test (85°C, 85%RH)
Initial
2184 h
Decrease in Pmax and FF is observed with DH test time increasing.
Acknowledgement
This research is supported by New Energy and Industrial Technology
Development Organization.
Back sheet (PVF/PET/PVF)
EVA
PV cell
EVA
Glass
Sensor
◆pH dependence of fluorescent spectra and FIR
1. Dropping a dye solution (0.1 mM, 100 μl)
onto a polytetrafluoroethylene membrane
filter (1 cm2, JGWP04700, Merck millipore)
2. Drying overnight
3. Heating at 80°C for 60 min
Near the
edge
Near the
center
Near the
edge
Near the
center
FIRs of the No. 1 to No. 14 sensors increased quicker than
those of the No. 15 to No. 20 sensors.
• Difference of FIR increasing rate
Generation rate of acetic acid was different.
Near the edge > Near the center
• Difference of FIR rise time
Water ingress / Acetic acid diffusion time until sensor was different.
SEM images of sensor
◆I-V curves ◆Fluorescent spectra and FIR changes
No.1 No.2 No.3 No.4
No.5
No.6
No.7
No.8No.9No.10No.11
No.12
No.13
No.14 No.15 No.16
No.17
No.18No.19
No.20