Abstract

This paper describes standard and innovative methods for characterizing the mechanical properties of single-crystal silicon cells [orientation (100)] for photovoltaic applications. The knowledge of their mechanical properties is not completely known in the technical literature and this knowledge could enhance the results of modern simulation softwares. The silicon cells were investigated before and after an aging at 100°C for 100 h. In the technical literature, an annealing at temperatures ranging from 70°C up to 180°C is proposed as a possible way to reverse the degradation of such components caused by long-time exposure to daylight (light-induced degradation, LID), and to obtain a recovery of the efficiency. Nevertheless, little information about the influence of such an annealing on the panel mechanical performances is available. Universal instrumented hardness tests were carried out to estimate the Young’s modulus; the fracture toughness was calculated by measuring the lengths of the cracks originated from the imprint corners. Moreover, the threshold load under which no cracks appear was estimated. Finally, bending tests were performed to evaluate the mechanical resistance. Such tests were carried out on a tensile testing machine after the design and the realization of suitable devices assembled on the machine standard fixtures.

References

1.
Luczak
,
K.
,
Lund
,
C. P.
,
Jennings
,
P. J.
, and
Cornish
,
J. C. L.
, “
Recovery of Light Induced Degradation in Amorphous Silicon Solar Cells in Modules
,”
Conference Record of the 2006 IEEE 4th World Conference on Photovoltaic Energy Conversion
, Waikoloa, HI, May 7–12,
2006
,
IEEE
,
Piscataway, NJ
.
2.
Fanni
,
L.
,
Pola
,
I.
,
Burà
,
E.
,
Friesen
,
T.
, and
Chianese
,
D.
, “
Investigation of Annealing and Degradation Effects on A-Si Pv Modules in Real Operating Conditions
,”
24th European Photovoltaic Solar Energy Conference
, Hamburg, Germany, Sept 21–25,
2009
,
WIP-Renewable Energies
,
Munich, Germany
.
3.
Silva
,
P.
,
Macchi
,
E.
,
Bellarmino
,
M.
, and
Manzolini
,
G.
, “
Solar Thermodynamic Plants for Cogenerative Industrial Applications in Southern Europe
,”
Renew. Energ.
, Vol.
36
, No.
1
, pp.
235
243
.
4.
Bocchini
,
G. F.
,
Gerosa
,
R.
, and
Rivolta
,
B.
, “
On Elastic Properties of Steam-Treated PM Materials
,”
Powder Metall.
, Vol.
53
, No.
3
,
2010
, pp.
213
217
. https://doi.org/10.1179/174329009X442717
5.
Shetty
,
D. K.
,
Wright
,
I. G.
,
Mincer
,
P. N.
, and
Clauer
,
A. H.
, “
Indentation Fracture of WC–Co Cermets
,”
J. Mater. Sci.
, Vol.
20
,
1985
, pp.
1873
1882
. https://doi.org/10.1007/BF00555296
6.
Ponton
,
C. B.
and
Rawlings
,
R. D.
, “
Vickers Indentation Fracture Toughness Test, Part 2—Review of Literature and Formulation of Standardised Indentation Toughness Equations
,”
Mater. Sci. Technol.
, Vol.
5
,
1989
, pp.
961
976
. https://doi.org/10.1179/026708389790222852
7.
Coletti
,
G.
,
van der Borg
,
N. J. C. M.
,
De Iuliis
,
S.
,
Tool
,
C. J. J.
, and
Geerligs
,
L. J.
, “
Mechanical Strength of Silicon Wafers Depending on Wafer Thickness and Surface Treatment
,”
21st European Photovoltaic Solar Energy Conference and Exhibition
,
Dresden, Germany
, Sept 4–8,
2006
.
8.
Sangwal
,
K.
, “
Review: Indentation Size Effect, Indentation Cracks and Microhardness Measurement of Brittle Crystalline Solids—Some Basic Concepts and Trends
,”
Cryst. Res. Technol.
, Vol.
44
, No.
10
,
2009
, pp.
1019
1037
. https://doi.org/10.1002/crat.200900385
9.
Ebrahimi
,
F.
and
Kalwani
,
L.
, “
Fracture Anisotropy in Silicon Single Crystal
,”
Mater. Sci. Eng. A
, Vol.
268
,
1999
, pp.
116
126
. https://doi.org/10.1016/S0921-5093(99)00077-5
10.
Smithells Metals Reference Book
,
Brandes
E. A.
and
Brook
G. B.
, Eds.,
Elsevier
,
New York
.
11.
Wang
,
J.
,
Huang
,
Q.-A.
, and
Yu
,
H.
, “
Young’s Modulus of Silicon Nanoplates at Finite Temperature
,”
Appl. Surf. Sci.
, Vol.
255
,
2008
, pp.
2449
2455
. https://doi.org/10.1016/j.apsusc.2008.07.172
12.
Brodie
,
R. C.
and
Bahr
,
D. F.
, “
Fracture of Polycrystalline Silicon
,”
Mater. Sci. Eng. A
, Vol.
351
,
2003
, pp.
166
173
. https://doi.org/10.1016/S0921-5093(02)00829-8
13.
Coletti
,
G.
,
Tool
,
K.
, and
Geerligs
,
L. J.
, “
Mechanical Strength of Silicon Wafers and Its Modeling
,”
15th Workshop on Crystalline Silicon Solar Cell & Modules: Materials and Processes
,
Vail, CO
, Aug 7–10,
2005
, pp.
117
120
.
14.
Vitman
,
F. F.
and
Pukh
,
V. P.
, “
A Method for Determining the Strength of Sheet Glass
,”
Zavodskaya Laboratoriya
, Vol.
29
, No.
7
,
1963
, pp.
863
867
.
This content is only available via PDF.
You do not currently have access to this content.