Programm Photovoltaik Ausgabe 2009 ... - Bundesamt für Energie BFE

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technologies still suffer of transient effects due to a combination of different dark, light and/or temperature
exposure times. The dark storage had the strongest influence on CIGS and CdTe technologies. A
large effort is therefore dedicated to the understanding of the influence of dark storage and light soaking
on these technologies, and the development of a new test procedure applicable by all laboratories,
independently of the type of solar simulator. Parallel studies on CI(G)S and CdTe are under progress
at different laboratories to achieve this, included at ISAAC (see 1.2.3).
Within this RR, ISAAC‘s formerly introduced measurement procedure for CIGS modules [REF1] could
be tested for the first time within a large inter-comparison campaign. The procedure resulted to lead to
the highest indoor measured power values due to the capability to overcome the very short term relaxation
effects. This value seems to be currently the closest to the obtained STC power by outdoor
measurements. A second positive result for ISAAC was the possibility to verify the feasibility of the use
of filtered crystalline silicon reference cells without applying any mismatch correction. The intercomparison
to the other laboratories using either outdoor calibration procedures for the determination
of the module Isc or the calculation of the mismatch factor, showed that the ISAAC approach leads to
similar results as the other ones, but a general improvement in the measurement accuracy of thin film
technologies is crucial for the future. The goal of the second RR phase is to reduce the spread within
the laboratories for as many technologies as possible, by introducing unifying and improving the present
existing measurement procedures.
Second crystalline silicon and thin film Round Robin
Based on the findings of the first round-robin test, a second round-robin has been launched in 2008
with the goal to monitor the improvements achieved by the PERFORMANCE project. The round-robin
will get also deeper into performance measurements at low irradiances and different module temperatures,
insofar as such information is crucial for energy rating (see 3.1.1). The test samples for the second
RR consists partially of the same samples used for the first RR, to better verify the achieved improvements,
as well as some new test devices especially in the case of c-Si. The module manufacturers
have been involved and stabilisation procedures were performed according to their specifications.
The final results will be only available at the conclusion of the measurement campaigns. It is foreseen
that ISAAC receives the modules during the first half of 2009.
1.2.2 Upgrades of equipment and test procedures (WP1.2)
The following activities have been accomplished or started in 2008 at ISAAC with the objective to test
these new features within the second RR phase.
Most of the activities, except for a new electronic load for capacitive module measurements, are part
of the Swiss funded project n° 36508. More details about the equipment can be found in the respective
annual report 2008 [REF2].
� A collaboration has been started with Sinton Consulting to test the FMT-350 electronic load with
dedicated software for the measurement of capacitive modules.
� A new Pasan solar simulator model IIIb with better spectrum, uniformity and larger test area and
with optional irradiance attenuator filters (100,200,400,700 W/m²) have been purchased and their
installation is under progress.
� Two new blue rich lamps, 400Watt each, for the pre-conditioning of CI(G)S modules for IVmeasurement
have been implemented into the laboratory.
� Two new filtered reference cells for CdTe and a-Si technologies, a KG5 and a BG40, have been
purchased at ISE.
� Some hardware changes have been performed on the original PASAN IIIa electronic load to improve
the voltage measurement.
� A study is undergoing to validate the currently introduced spectral mismatch correction at ISAAC.
� A new high precision equipment for the regular control of the main solar simulator characteristics
(spectrum, uniformity and stability) is under development.
� An automatic spectral filter unit for the new PASAN solar simulator IIIb is under construction,
permitting in the near future to perform spectral response measurements of single junction PV
modules.
1.2.3 CI(G)S measurement study (WP1.3)
The formerly introduced experimental procedure for the maximum power determination of CI(G)S
modules by ISAAC, based on the use of bias lights before and during IV-scan to stabilise the electrical
performance, is currently under further investigation. The first bias light measurements were per-
PERFORMANCE, G. Friesen, SUPSI, ISAAC-TISO
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