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 PHOTOVOLTAIC LABORATORY (L-9)


Scope of accreditation of research laboratory No AB 120
issued by Polish Centre for Accreditation Issue No. 12 of 7 July 2015



Head of the laboratory

The experts

Prof. Marek Lipiński, PhD, DSc
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Kazimierz Drabczyk, PhD, Eng - Deputy Head of the Laboratory
Piotr Panek, PhD

Postgraduates: (research students, PhD students)
Grażyna Kulesza, MSc, Eng
Zbigniew Starowicz, MSc, Eng


Address:

Institute of Metallurgy and Materials Science Polish Academy of Sciences

ul. Reymont 25, 30-059 Krakow

phone: (48) 12 295 28 98, fax: (48) 12 295 28 04

e-mail: Adres poczty elektronicznej jest chroniony przed robotami spamującymi. W przeglądarce musi być włączona obsługa JavaScript, żeby go zobaczyć. , website: http://www.imim.pl


Photovoltaic Laboratory

22 Krakowska St. PL-43340 Kozy

phone: (48) 33 817 4249


Apparatus:

Module Solar Simulator
Series: Quick Sun 820A, Producer: Endeas Oy

The simulator is designed to measure current-voltage characteristics and the resulting electrical parameters of PV modules. This device consists of a high quality light source in the form of flash Xenon Lamp, which allows illuminating the module with the light similar to the sunlight during the measurement. This lamp is supplied with flash generators, which transfer the energy appropriate to the research carried out under the STC (Standard Test Conditions). Moreover, simulator is equipped with a central processing unit allowing the flash control and data acquisition. The Endeas software is responsible for processing the data obtained during the measurement. Additionally, the entire device is equipped with a special test frame for conducting measurements in total blackout and infrared sensor for non-contact temperature measurement module.
The individual components of the measurement system are shown schematically in Fig. 1.

 

 

Fig. 1. The scheme of the measurement system - simulator for the measurement of PV modules electrical parameters.

During the module measurements, the connection based on the 4-probes measurement principle is used, what allows to measure correctly the electrical parameters of PV modules without loss of power associated with the resistance of the cables and connectors.
Complete current-voltage characteristics are obtained after one flash at a given radiation intensity level when the module is connected to the measurement circuit. It is possible to carry out the tests under STC (1000 W/m2), and for any radiation power in the range 200-1000 W/m2 for the spectrum of AM 1.5.

 

The results are presented in a graphical and numerical form. Numerically determined are:

ISC - short circuit current,
IMP - current in the maximum power point,
VOC - open circuit voltage,
VMP - voltage in the maximum power point,
PM - maximum power,
FF - fill factor,
Eff - photovoltaic conversion efficiency.
In addition, there are numerically determined parameters such as:
RS - series resistance
RSH - shunt resistance

Numerical and graphical measurement result is shown in Fig. 2.



Fig. 2. The window depicting the result of the module measurement.

Solar simulator works in measurement class of AAAA determined in accordance with IEC 60904-09, ed. 2. Basic technical parameters of the simulator and AAAA class consisting parameters are shown in Table 1

Table 1. Quick Sun 820A simulator parameters

Parameter
Value (testing class)
 Max. module size [cm x cm]  200 x 120
 No. measurements over time of 1 h 120
 Measurement cage size [cm x cm x cm]] 465 × 240 × 250
 Lamp pulse duration [ms] 15
 Radiation intensity [W/m2] 200 ÷ 1000
 Lamp lifetime [flash] 40 000
 Spectrum < ± 25% (A)
 Non-Uniformity < ±2% (A)
 Short term instability (STI) < 0,5% (A)
 Long term instability (LTI) < ±2% (A)


Preparation of tested samples:
The measurement is acceptable for the photovoltaic modules made of monocrystalline, polycrystalline silicon and thin-film amorphous silicon as well.
The laboratory performs tests on PV modules supplied by the customer. During the reconciliation of the order conditions the customer is informed about the requirements for the modules and how they should be prepared for the tests.

Photovoltaic module for testing should have dimensions not exceeding 200 x 120 cm.


Solar Simulator with the system for I-V characteristic measurements of solar cells
Solar Simulator: Model SS 200AAA
Producer: Photo Emission Tech Inc.
System for I-V characteristic measurements of solar cells: „Solar cell I-V curve tracer" model SS I-V CT-02" with the Auxiliary Unit ver.2
Producer: PV Test Solutions Tadeusz Żdanowicz

Solar Cells Simulator with the I-V characteristics measurement system is designed for the measurements of current-voltage characteristics in the STC (Standard Test Conditions) defined by European standard IEC 60904-3 as irradiance with spectrum corresponding to AM1.5 (G means global) equal to 1000 W/m2 and cell temperature 25 oC and NOCT (Nominal Operating Cell Temperature Conditions according to the IEC 61853-1) conditions respectively. System for I-V characteristic measurements of solar cells meets all requirements of the IEC 60904-1 standard. The all components of the system are presented in Fig. 3 - 5.

Used four probes (Kelvin) technique is necessary to correct measurement of the electrical parameters of solar cells without power losses associated with the resistance of the cables and connectors. This means that two separate probes are needed to electrical current flow through the cell while other two are used to directly measure voltage drop on the cell. In this system brass plate with polished and gold plated surface serves as the back current probe. Inside the table, in its central part, two voltage gold plated probes for solar cell back-side contacting are located. These probes are electrically isolated from the table. Contacting to solar cell's front side is provided by the set of four coupled voltage/current gold-plated telescopic probes. Additionally, also another probing option is used. This is a system with two or three sets of multi-pin soft-touch gold plated probes mounted to the aluminium frame (Fig.4). This system is suitable for testing large amount of big solar cells (≥16,5 x16.5 cm).

A Heating-Cooling Controller has been designed to control the temperature of the measuring table in the ranger of ~0-60 oC. This is done by supplying electrical current to set of four Peltier elements having total maximum rated power of about 280 W. The elements have been attached to the rear side of the measuring table. Depending on the direction of the current through Peltier elements the table may be either heated or cooled.

This I-V measurement system measures I-V curves of solar cells both in dark as well in light mode. Light I-V characteristics are registered under stable light of specified intensity. Numerical and graphical measurement result is shown in Fig. 5.

The result of the measurement is characteristic I-V in a graphical and in standard text (ASCII) file, and set of numerical data and cell parameters:

ISC - short circuit current,
IMP - current in the maximum power point,
VOC - open circuit voltage,
VMP - voltage in the maximum power point,
PM - maximum power,
FF - fill factor,
Eff - photovoltaic conversion efficiency.

In addition, there are numerically determined parameters such as:

RS - series resistance
RSH - shunt resistance

To determine

In order to accurately determine the series resistance, the procedure described in the standard IE60891 has been applied. This procedure requires measurement of the two I-V curves under two significantly different light intensities.

Additionally, data I-V may be subjected to additional analysis by fitting I-V curve to specified cell's equivalent diode model (SEM, DEM or VDEM).

The result is a diode parameters such as dark current density, diode quality factor, series and parallel resistance.

 

 Fig. 3. The view of the setup for measurement I-V characteristics of solar cells

 

 Fig. 4. Measuring table with the multi-pin voltage/current probes of the setup (Fig.3).

 

 Fig.5. View of Heating - Cooling controller unit (a) and view of the Solar Cells I-V Curve Tracer unit SSI-VCT-02 and Auxiliary Unit ver.2 with the Keihley 2401 Sourcemeter (b) of the setup (Fig.3).

 

 Fig. 6. Light I-V characteristic of measured solar cell.

 

The current range of the SS I-V CT-02 system is 100 m ÷15 A. Additional unit 15 Axu ver. 2 together with the Keithley 2401source meter is especially assigned for measuring organic and DSC solar cells with very small short-circuit currents of nanoamperes.

For the measurement of the test organic cell is a special test board from Ossila company which allows for easy attachment and removal of cell in the form of pixels (6 pixels) with a size of 1.5 mm x 3 mm. The board is connected to the I-V characteristics system using the BNC socket.

To measure the silicon cells, DSC and organic cells certified references measured at the Institute Fraunhofer ISE under STC conditions are used. These are the three monocrystalline silicon cells 2x2cm2 without the filter for silicon solar cells measuring and with KG-3 and KG-5 filters for measuring organic and pigmented cells.

Solar cell simulator works in measurement class of AAA determined in accordance with IEC 60904-09, ed. 2. Basic technical parameters of the simulator and AAA class consisting parameters are shown in Table 2.

Table 2. SS 200AAA simulator parameters

 Parameter
 Value (testing class)
 Max. cell size [cm x cm] 20x20
 Lamp power 1,43kW
 Air Mass1,5G
 Radiation intensity [W/m2] 800 ÷ 1000 ± 15%
 Max. range of cell voltage ±10 V
 Max. range of cell current ±20 A
 Simulator class (AAA)
 Spectral Match to ASTM E927 < ± 25% (A)
 Non-uniformity of irradiance 2% or better (A)
 Temporal stability 2% or better
 (A)

 

Preparation of tested samples:

Cells acceptable to measure are : crystalline silicon (Cz-Si, mc-Si), polymer and organic devices.

The laboratory performs tests on solar cells supplied by the customer. During the reconciliation of the orders conditions the customer is informed about the requirements for the cells and how they should be prepared for the tests.

Solar cells for testing should have dimensions not exceeding 20 x 20 cm.

Customers interested in cooperation are kindly asked to contact the:

 


Spectrophotometer UV-VIS-NIR
Series: Lambda 950 S
Producer: Perkin Elmer

Spectrophotometer Lambda 950 S (Fig. 7) is designed for optical parameters measurements especially: reflectance, transmission coefficient in the solid and liquid materials in the wavelength range of 200 - 2500 nm.  

 

Fig. 7. Spectrofotometer UV-VIS-NIR Lambda 950S

 

The individual components of the measurement system are shown schematically in Fig. 8.

 


Fig. 8. Scheme of Spectrophotometer Lambda 950S

1- Deuterium and Tungsten Halogen Light sources        6- Sample and Reference Beam Attenuators
2- Double Holographic Grating Monochromators             7- Largest Sample Compartment in the Industry
3- Common Beam Mask                                                        8- High Sensitivity PMT and Temperature Stabilized PbS Detectors
Common Beam Depolarizer (Optional)                               9- Second Sampling Area
5- Chopper High-sensitivity PMT, 3-stage Peltier
Cooled InGaAs and Temperature Stabilized PbS Detectors

Spectrophotometer is not equipped with the elements designated as 4 and 10.

Spectrophotometer is equipped with integrating sphere with the diameter of 15 cm allowing the measurement of the total reflectance and transmission as well as their diffusive components. The measurements principles of above parameters are shown in the Fig. 9. Spectrophotometer is equipped with two light sources: the deuterium and tungsten, and two detectors (PMT and PbS).

 

 Fig. 9. Scheme of the total and diffuse components of reflectance and transmittance.

The samples are placed in front of (transmission) or behind (reflection) integrating sphere, and samples in liquid state are placed in a separate compartment in a cuvette. In addition, using special attachment, it is possible to measure the reflectance at different angles between the incident beam and sample surface. Quick analysis of the spectra is possible using installed UV VinLab program. All measurements are performed using certified by Perkin Elmer white pattern technically called Spectralon.

The device has a declaration of all the quality requirements confirmed by a test certificate in accordance with the requirements of the quality management system in accordance with ISO 9001.

Table 3. Lambda 950 S parameters

 Parameter
 Wartość
 Wavelength range 200 ÷ 2500 nm
 Light source deuterium and tungsten lamp, automatically switched depending on the light spectrum
 Optical system double-beam with the radiation beam aperture
 Integrating sphere sphere 15 cm diameter for total and diffuse light measurement in the range 200 ÷ 2500 nm
 Detectors photomultiplier for UV-VIS and cooling by a Peltier's system PbS detector for NIR
 Resolution for UV/VIS ≤ 0,05 nm
 Resolution for NIR ≤ 0,20 nm
 Wavelength accuracy for UV/VIS ≤ ± 0,08 nm
 Wavelength accuracy for NIR ≤ ± 0,3 nm


Preparation of tested samples:

The laboratory performs tests on samples supplied by the customer. During the reconciliation of the orders conditions the customer is informed about the requirements for the samples and how they should be prepared for the tests.

Samples for testing should have dimensions exceeding 2.5 cm in diameter.


Customers interested in cooperation are kindly asked to contact the:

Head of the laboratory L-9:
Prof. Marek Lipiński, PhD, DSc.
tel: 33 817 42 49 e-mail: Adres poczty elektronicznej jest chroniony przed robotami spamującymi. W przeglądarce musi być włączona obsługa JavaScript, żeby go zobaczyć. or Adres poczty elektronicznej jest chroniony przed robotami spamującymi. W przeglądarce musi być włączona obsługa JavaScript, żeby go zobaczyć.