The Zebra Cell Concept - ISC Konstanz

optimized technique in the fabrication process”, Energy Procedia
8, 2011, p. 421
[6]: L. J. Koduvelikulathu, V. M. Mihailetchi, A. Edler, C.
Comparotto, A. Halm, R. Kopecek, K. Peter, “Metallization and
firing process impact on the V OC – a simulation study”,
proceedings of this conference
[7]: K. Mangersnes “Back-contacted back-junction silicon solar
cells”, PhD. thesis, University of Oslo, October 2010
Figure 5: comparison of the normalized power output of
a monofacial versus a bifacial one-cell Zebra module for
a clear day; blue: P MPP /P MPP@1sun for the bifacial module;
black: P MPP /P MPP@1sun for the monofacial module; green:
outdoor light intensity measured by pyranometer; orange:
albedo contribution quantified by I SC /I SC@1sun of the facedown
mounted module.
Figure 5 shows the same measurement done on a clear
day. Here, bifacial module is generating 12.2 % more
power. Over the whole period 21 days the power gain for
the bifacial module with transparent backsheet comparing
to the monofacial module with black backsheet is 13 %.
This is a significant increase of the energy harvest
favoring bifacial operation of the Zebra cell. Indoor
measurements of one-cell Zebra modules using a bifacial
measurement setup as shown in [3, 4] yield in similar
results.
3. SUMMARY
We fabricated highly efficient IBC solar cells, named
“Zebra” cells, on 156 x 156 mm² n-type Cz wafers using
only industrial relevant processing equipment. We prove
stable efficiencies on batches of maximum 28 wafers
testing substrates of different suppliers and base
resistivity. So far, we reached 21.3 % maximum
efficiency with our cell concept. We showed that the
Zebra cell is ready for module assembly and presented
first results of the outdoor performance of bifacial versus
monofacial one-cell modules.
4. REFERENCES
[1]: D. M. Chapin, C. S. Fuller and G. L. Pearson “A New
Silicon p-n Junction Photocell for Converting Solar Radiation
into Electrical Power”, JAP Vol. 25 (1954) p. 676-677
[2]: D. De Ceuster et al., Proceedings of 22 nd EU-PVSEC, Milan
(2007), p. 816
[3]: V.D. Mihailetchi et al. “high efficiency ibc solar cells
fabricated on large area n-type silicon using industrial available
techniques”, technical digest, 21 International Photovoltaic
Science and Engeneering Conference 28.11.2011-2.12.2011,
Fukuoka, Japan
[4]:G. Galbiati, V. D. Mihailetchi, A. Halm, L. J.
Koduvelikulathu, Razvan Roescu, R. Kopecek, K. Peter, J Libal
“Large Area Back-Contact Back-Junction Solar Cells with
Efficiency Exceeding 21%”, 38th IEEE Photovoltaic Specialist
Conference 2012, Austin, USA
[5]: G. Galbiati, V.D. Mihailetchi, A. Halm, R. Roescu, R.
Kopecek, “Results on n-type IBC solar cells using industrial