Issue 10 Volume 41 May 16, 2003

We have investigated and compared material properties and solar cells of several common multicrystalline ingots. Apart
from the contaminated end parts of the ingots the cell quality correlates well with the as-received lifetime, and the lifetime
profile through the ingot correlates with the distribution of defect densities in the material. The asreceived lifetime after light
soaking is a reasonable predictive parameter for cell performance for the complete ingot if the major impurity in the end parts
is iron, and if the oxygen concentration is low. A high oxygen concentration of 15-20 ppma in the bottom parts of some ingots,
instead of the more common 5-10 ppma for that position, correlates with a strong reduction of cell efficiency.
NTIS
Ingots; Solar Cells; Mechanical Properties
20030036974 Netherlands Energy Research Foundation, Petten
Simple, Detailed and Fast Firing Furnace Temperature Profiling for Improved Efficiency
Hoornstra, J.; van der Heide, A.; Bultman, J.; Weeber, A.; 2002; 8 pp.
Report No.(s): PB2003-102653; Copyright; Avail: National Technical Information Service (NTIS)
A new temperature profiling method in a firing furnace is demonstrated. A data logger in a thermal barrier is connected
to a thermocouple traveling through the furnace. The use of smaller and multiple thermocouples attached to a wafer enable
more accurate profiling than the commonly used method. Possibilities for improving the firing furnace could be determined
using the data logger and contact resistance scans made with the Corescan.
NTIS
Temperature Distribution; Furnaces; Energy Conversion; Thermodynamic Effıciency
20030036975 Netherlands Energy Research Foundation, Petten
Locating Losses Due to Contact Resistance, Shunts and Recombination by Potential Mapping with the Corescan
van der Heide, A. S. H.; Bultman, J. H.; Hoornstra, J.; Schoenecker, A.; Wyers, G. P.; Aug. 2002; In English
Report No.(s): PB2003-102650; ECN-RX-02-039; Copyright; Avail: National Technical Information Service (NTIS)
A visualization tool to locate losses in a solar cell can be very helpful in troubleshooting a non-optimal production line.
Therefore, the Corescan has been developed, in which three different locating methods are incorporated, the Corescan,
Shuntscan and the new Voc scan. In this paper it is explained how the scan results have to be interpretated and it is shown
that the sensitivity of the methods is more than sufficient. The unique Voc scan method is introduced for the first time; this
technique can locate recombination losses on cells that are almost complete (only the front contact has to be omitted). Several
examples of how the Corescan instrument can be used for troubleshooting and process optimization are presented in this paper.
These examples will help users of the instrument to relate measured scans with reasons for non-optimal processing.
NTIS
Solar Cells; Contact Resistance; Bypasses; Circuits
20030036977 Netherlands Energy Research Foundation, Petten
Selecting Optimal Interconnection Methodology for Easy and Cost Efficient Manufacturing of the Pin Up Module
Bultman, J. H.; Eikelboom, D. W. K.; Kinderman, R. K.; Tip, A. C.; Weeber, A. W.; 2002; 8 pp.
Report No.(s): PB2003-102655; Copyright; Avail: National Technical Information Service (NTIS)
Rear contacted solar cells are successfully glued onto an interconnection foil which also serves as the environmental
barrier at the rear of the module. Resulting fill factors are similar to cells connected with strips that are soldered and glued.
Glued cells are interconnected and laminated in a single step, which reduces labor to a minimum, reduces stress on the cells,
and therefore could increase process yield. Considering these advantages, this concept has the potential to interconnect very
thin cells without additional stress on the cells.
NTIS
Costs; Manufacturing; Solar Cells; Joining; Energy Technology; Methodology
20030036979 Netherlands Energy Research Foundation, Petten
PV-Wirefree: Redesigning and Innovating Grid-Connected PV-Systems
Oldenkamp, H.; de Jong, I.; Sinke, W. C.; 2002; 8 pp.
Report No.(s): PB2003-102656; Copyright; Avail: National Technical Information Service (NTIS)
In this paper a new concept for designing grid-connected PV-systems is presented: PV-wirefree, aiming at minimizing PV
BOS costs Balance of System costs - and inherently safe PV-systems. The guiding design principles used are: minimize
dc-voltage, minimize components and material, integrate functions, simplify the PV-system and design for easy installation.
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