Radiation damage of solar cells

Radiation damage of solar cells

ARTICLE IN PRESS Radiation Physics and Chemistry 71 (2004) 891–892 Radiation damage of solar cells Peter Kozmaa,*, Petr Kozma Jr.b a Institute of T...

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ARTICLE IN PRESS

Radiation Physics and Chemistry 71 (2004) 891–892

Radiation damage of solar cells Peter Kozmaa,*, Petr Kozma Jr.b a

Institute of Technological Investigations, 251 63 Strancˇice, Spojovac!ı 377, Prague Eastern Districe, Czech Republic b YXELL Ltd., Hi-tech and Engineering, 251 63 Strancˇice, Spojovac!ı 377, Czech Republic

The operating behaviour of a solar cell is defined by its voltage–current (V–A) characteristic (see Fig. 1), from which all relevant parameters ISC, UOC, Ipmax, Upmax and Pmax can be unambiguously determined (Schulte et al., 1993). Radiation damage was examined by the measurement of these effective solar cell characteristics before and after irradiation. Solar cells from various manufacturers, as detailed in Table 1, were irradiated by a low energy gamma-ray source, 60Co, under conditions identical to those described in Kozma et al. (1993). Peak–power and voltage–current (Volt– Ampere, i.e. V–A) characteristics have been measured by the method described in detail by Wagner (1999). It

The experimental study of the long-term stability of relevant parameters of solar cells (SC) and photovoltaic (PV) modules is highly desirable because of the correct long-term warranty of these devices. Taking into account the average flux of ionising radiation exposure on PV area (about 800 Wm2 year1) and the definition of an appropriate dose (1 rad=J kg1), one can simply deduce that during the 30-year lifetime of a typical sensitive PV solar cell of area of about 100  100 mm2 it is receives about 2400 rad. Therefore the radiation tolerance of monocrystalline and multicrystalline solar cells from several manufacturers (see Table 1) has been studied for doses up to this value.

Table 1 Physical properties and V–A characteristics of solar cell samples Manufacturer EUROSOLARE INTERTECHa SOLARTECHb BP SOLAR ASTROPOWER ISOFOTON Q-CELLS SUNWAYS TESSAG

Sample CM-102/A ITS-100 SC 2255 BP-585 A-104 I-100 HQ-12-1440 A701150 EFG1028

Type

Size c

mono mono mono mono mono mono multid multi multi

00

4 400 400 500 400 400 500 400 400

Shape e

PSQ PSQ PSQ PSQ FSQf PSQ FSQ FSQ FSQ

UOC (V)

ISC (A)

Upmax (V)

Ipmax (A)

Pmax (W)

0.593 0.588 0.604 0.601 0.570 0.576 0.605 0.594 0.587

3.36 2.53 3.37 4.95 3.12 3.20 4.91 2.74 3.06

0.482 0.471 0.509 0.486 0.483 0.484 0.486 0.478 0.475

3.02 2.83 3.18 4.72 2.88 2.65 4.63 2.56 2.75

1.455 1.333 1.619 2.295 1.391 1.283 2.250 1.225 1.306

a

INTERTECHNOLOGY. Moscow, Russia. SOLARTECHs Corp.. Prague, Czech Republic. c Monocrystalline solar cells. d Polycrystalline solar cells. e Pseudo-square. f Full-square. b

*Corresponding author. Tel.: +420-323-640-176; fax: +420-323-640-438. E-mail address: [email protected] (P. Kozma). 0969-806X/$ - see front matter r 2004 Published by Elsevier Ltd. doi:10.1016/j.radphyschem.2004.04.117

ARTICLE IN PRESS P. Kozma, P. Kozma Jr. / Radiation Physics and Chemistry 71 (2004) 891–892

892

5.0

4.0

Isc

3.0

Ipmax

Amps

Pmax [W] before irradiation

after irradiation 2.0

1.0

0.0 0.0

0.1

0.2

0.3

U pmax

0.4

Uoc

0.5

Volts

Fig. 1. Voltage–current (V–A) characteristics of monocrystalline solar cell (SC 2255 SolarTechs) before and after irradiation: Isc=Short-circuit current; Uoc=Open-circuit voltage; Ipmax=Current at maximum power point; Upmax=Voltage at maximum power point; Pmax=Ipmax  Upmax=maximum peakpower (W).

Table 2 Degradation of maximum power output Pmax of solar cells after irradiation Manufacturer

Pmax (W) before irradiation

Pmax (W) after irradiation

Absolute degradation of Pmax

EUROSOLARE INTERTECH SOLARTECH BP SOLAR ASTROPOWER ISOFOTON Q-CELLS SUNWAYS TESSAG

1.455 1.333 1.619 2.295 1.391 1.283 2.250 1.225 1.306

0.894 1.046 1.418 2.038 1.118 0.915 0.948 1.072 1.059

38.6% 21.5% 12.4% 11.2% 19.6% 28.7% 24.2% 12.5% 18.9%

should be noted that all the V–A parameters were determined under standard test conditions (IEC 609043, 1993). The changes of V–A characteristics of a monocrystalline solar cell, sample SC 2255 (102.5  102.5 mm2, pseudosquare shape with diagonal of 135 mm) after absorption of 2400 rad are also displayed in Fig. 1 where it can be seen that, after irradiation, Pmax decreases of about 12.4%. Comparisons of Pmax before and after irradiation, as well as the absolute degradation of maximum power output, are listed in Table 2. The absolute degradation of peak– power was found to be between 11.2% and 38.6% for monocrystalline SC, as well as 12.5% and 24.2% for multicrystalline SC, respectively. Relevant results of the experimental study of radiation damage of crystalline solar cells will be published in details later (Kozma and Kozma, 2004). We will also proceed to study radiation damage of SC and PV more

systematically. We intend particularly to study dependence of possible V–A changes on the exposition dose and changes of solar cell efficiencies, as well.

References IEC-60904-3, 1993. Procedures for temperature and irradiance correction to measured V–A parameters of crystalline photovoltaic devices. Kozma, P., Afanasiev, S., Malakhov, A., Povtoreiko, A., 1993. Radiation resistivity of large CeF3 crystals. Nucl. Instrum. Methods A328, 599. Kozma, P., Kozma, P., Jr., 2004. Progress in Photovoltaics, in preparation. Schulte, K.M., Sommerfeld, A., Wagner, A., 1993. Mobiles mess-systems fu¨r PV-Stromversorgungsanlagen, Final report of research project, AG-Solar NRW, Ju¨lich. Wagner, A., Photovoltaik Engineering, Springer, Berlin, 1999.