This document summarizes a study comparing different architectures of bifacial solar modules. Indoor characterization of standard and bifacial modules was performed on a solar simulator. Outdoor testing was also conducted on small bifacial modules installed vertically east-west. Preliminary results show that modules with an up-down cell configuration performed better than up-up under bifacial illumination conditions, and gained up to 40% more power from ambient light compared to monofacial modules. Further indoor and outdoor testing is planned to better understand bifacial module performance and the potential to predict outdoor gains using indoor characterization methods.

1. 120/04/2012
Characterization of bifacial modules of
different architectures
Bruno Soria
Yannick Veschetti
Paul Lefillastre
Eric Gerritsen
Cell & Module Laboratory
French National Institute for Solar Energy
24th April 2012

2. 224th April 2012 bruno.soria@cea.fr
60’s 2008 FUTURE
- Context and aim of the study -
70’s
Aim of this study :
• Comparing different architectures
of bifacial modules.
• Studying the potential of a new
characterization setup on solar
simulator.

3. 324th April 2012 bruno.soria@cea.fr
1. Cell and module architecture
2. Standard indoor characterization
3. Bifacial indoor characterization
4. Outdoor tests and follow up
- Content -

4. 424th April 2012 bruno.soria@cea.fr
1. Cell and module architecture
2. Standard indoor characterization
3. Bifacial indoor characterization
4. Outdoor tests and follow up
- Content -

5. 524th April 2012 bruno.soria@cea.fr
- Cell and module architecture -
N-type PERT bifacial cells
Boron emitter
156PSQ Cz substrates
Efficiency of 92% FAR/FAV
Symetrical rear and front grid
Substrate features Measurement Jsc (mA/cm²) Voc (mV) FF (%) η (%)
Cz , 239.6 cm²
FAV 38.8 627.4 77 18.7
FAR 35.3 624.5 78 17.2
Si(n) Phosphorus BSF
Boron Emitter
Thermal SiO2 SiNx
Rear s.p. grid
Front s.p. grid
Thermal SiO2 SiNx ARC
Strongly influenced by chuck reflectivity and surface contacts

6. 624th April 2012 bruno.soria@cea.fr
- Cell and module architecture -
NICE technology :
Lower material and process cost
Recycling possibility
STANDARD technology (APOLLON SOLAR)
Architecture
Advantages
PIB rub
glass
PRESSED
EVA UV clear
LAMINATED
glass
EVA UV clear :
glass glass
Module NOT OPTIMISED :
No AR coating on glass
Depression inside
Black PIB rub

7. 724th April 2012 bruno.soria@cea.fr
- Cell and module architecture -
UP - UP UP – DOWN (patent Kopecek)
Interesting with NICE technology
(mechanical contact)

8. 824th April 2012 bruno.soria@cea.fr
- Cell and module architecture -
STANDARD technology
UP - UP UP - DOWN UP - UP UP - DOWN
FRONT
REAR

9. 924th April 2012 bruno.soria@cea.fr
1. Cell and module architecture
2. Standard indoor characterization
3. Bifacial indoor characterization
4. Outdoor tests and follow up
- Content -

10. 1024th April 2012 bruno.soria@cea.fr
- Standard indoor characterization -
• Module : front & rear independently
with black mask around cells
and black mask on backside
• Set up : PASAN Class IIIb solar simulator

11. 1124th April 2012 bruno.soria@cea.fr
- Standard indoor characterization -
STANDARD technology
UP - UP UP - DOWN UP - UP UP - DOWN

12. 1224th April 2012 bruno.soria@cea.fr
Standard – UP UP
Standard – UP DOWN
• UP DOWN -> flat
- Standard indoor characterization -
• UP UP -> not flat
Repartition of ratio :
From front anf rear spectral responses :
[similar shapes for NICE]

13. 1324th April 2012 bruno.soria@cea.fr
1. Cell and module architecture
2. Standard indoor characterization
3. Bifacial indoor characterization
4. Outdoor tests and follow up
- Content -

14. 1424th April 2012 bruno.soria@cea.fr
- Bifacial indoor characterization -
Set up : PASAN Class IIIb + MOUNTING => creating a standard optical environment

15. 1524th April 2012 bruno.soria@cea.fr
- Bifacial indoor characterization -
Ibifacial = Ifront + Irear
Vbifacial = av (Vfront, Vrear)
STANDARD technology
UP - UP UP - DOWN UP - UP UP - DOWN

16. 1624th April 2012 bruno.soria@cea.fr
UP DOWN architecture
UP UP architecture
Front illumination Back illumination Bifacial illumination
Front illumination Back illumination Bifacial illumination
- Bifacial indoor characterization -

17. 17bruno.soria@cea.fr
- Bifacial indoor characterization -
Black White
Alu
diffuse
Alu
specular
[similar for NICE]
24th April 2012

18. 1824th April 2012 bruno.soria@cea.fr
Set up limitations :
- Irradiation correction : 2 monitor cells in the
module plane
- Uniformity of irradiance ? To be measured soon
- Spectral mismatch due to mirror
- Size of set up for real size modules
- Bifacial indoor characterization -
Further studies :
Influence of the ANGLE

19. 1924th April 2012 bruno.soria@cea.fr
1. Cell and module architecture
2. Standard indoor characterization
3. Bifacial indoor characterization
4. Outdoor tests and follow up
- Content -

20. 2024th April 2012 bruno.soria@cea.fr
- Outdoor tests -
Coming soon, case study :
BIFACIAL vertically installed EAST – WEST
Advantages :
• no snow, no dust,…
• better match with electrical consumption
Aim :
LINKED
WITH ?
Possible to avoid long term outdoor test to measure potential of bifacial modules ?

21. 2124th April 2012 bruno.soria@cea.fr
Importance of ambient diffuse light (white : +10%)
Outdoor tests on small bifacial modules so far :
- Outdoor tests -

22. 2224th April 2012 bruno.soria@cea.fr
REFERENCE
First results :
• White : +10% than REF
• Black : -10% than REF
Module bifacial
Bureaux
Module bifacial
Bureaux
Ongoing test : BIFACIAL BIPV
- Outdoor tests -
Case study

23. 2324th April 2012 bruno.soria@cea.fr
Comparison of modules :
 Proof of concept : NICE bifacial UP DOWN => can be improved !
 Performance on bifacial illumination : UP DOWN ~ UP UP
 Gain bifacial / monofacial : UP DOWN > UP UP
New characterization setup :
 Bifacial illumination (2 mirrors) => no Jsc limitation => no FF increase
 Several possible configurations : surfaces, angles,…
 up to 40% gain due to white surface on back side
Outdoor tests : possible to predict outdoor gain with indoor setup ?
- Conclusion and perspectives -

24. Merci de votre attention
2420/04/2012
Many thanks for your attention !
Acknowledgements :
Guillaume RAZONGLES, Yves DELESSE (Solar System Lab - INES)
Brigitte ASSOA, Florian SAINT-PIERRE (Energy Building Lab - INES)
Armand BETTINELLI (PV Cell Lab – INES)
Jean-Emmanuel BROQUIN (Minatec – Grenoble INP)
Oleksiy NICHIPORUK (nichiporuk@apollonsolar.com), Julien DUPUIS (dupuis@apollonsolar.com)
CONTACT : bruno.soria@cea.fr