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

The short circuit current of each PV cell is measured separately and simultaneously. For every flash
and every PV cells 50 measurement points are entered. The data are transmitted at the end of the
measurement to a PC for the elaboration. The development of the electronics part is done at the
ISAAC with the collaboration of the electronic department (DTI - ISEA) of SUPSI.
Moreover, thanks to a further extra funding by SUPSI, a new Pasan class A solar simulator has been
acquired (see Figure 3). Its features will allow measuring most of the high capacitance modules
(10 ms pulse duration), a more accurate I-V measurement at low irradiances, better uniformity, etc.
Figure 3: New PASAN class A solar simulator with manual filter loader.
Through the next year functionality tests with the verification of uniformity and light spectrum will be
performed. After a testing period they will be inserted in the accreditation system ISO17025 for the
measurements I-V at STC.
A new and bigger insulated chamber, with air conditioning control, has been installed in the dark room.
The climatization allows the independent control of the temperature in the chamber and in the dark
room.
Annual Round Robin
Every year tests of comparison are carried out with other agencies and laboratories as a further verification
of the stability of the measurement system. The Round Robin is performed separately from the
one realized in the project PERFORMANCE [2].
This year TÜV (Köln) was the partner for the annual Round Robin – together with ECN (Petten) - instead
of the ESTI laboratory of the JRC (Ispra, Italy). A new module has been chosen to have a reference
with characteristic as near as possible to the modules currently present on the market. At this
purpose, a Solar World SW165poly - a module bigger and more powerful than the previous Kyocera
LA361K51S (51 W) - has been selected.
In May 2008 the reference module has been measured at ISAAC (I-V @STC, temperature coefficients
determination and I-V at different irradiances) and then sent to TÜV. Unfortunately, with an electroluminescence
test TÜV discovered that the majority of cells showed micro-cracks and non-active parts.
The Round Robin has been interrupted.
Indoor MEASUREMENT OF THIN FILM MODULES
In order to accurately measure thin film modules it is necessary to improve on the current equipments
at ISAAC. For instance some modules require a “pre-conditioning”, consisting on the application of
electrical or light conditions before the start of the IV measurement. Others need a spectral mismatch
correction on the relative IV measurement. This correction is accurately performed through the measurement
of the spectral response (SR) and the monitoring of the flash spectrum.
A bias light measurement procedure for the maximum power determination of CI(G)S module at STC
was introduced at ISAAC. Two new spotlights with metal halide bulbs were installed (OSRAM model
HQI / D - daylight - with a high intensity in the blue spectrum).
When tested and reference devices have not same spectral response, changes in solar spectrum can
differently affect on their responses. This is often the case of a-Si and CdTe PV modules when tested
with c-Si reference cells as irradiance sensors. Consequently this can have an influence on IV result
accuracy. In order to face this issue, the current strategy foreseen at ISAAC consists in implementing
the SR measurement and the monitoring of the flash spectrum. In fact these allow to properly calcu-
Centrale di test ISAAC-TISO, D. Chianese, SUPSI, DACD, ISAAC-TISO
204/290
4/8