knjiga solarna energija dobra

ADDITIONAL TOPICS 103
4.0
3.5
3.0
R s = 200 mΩ
R s = 50 mΩ
R s = 0 Ω
Cell current
[A]
2.5
2.0
1.5
IR s
1.0
0.5
0.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Cell voltage
[V]
Figure 3.22
(R Sh →∞)
Effect of series resistance on the current–voltage characteristic of a solar cell
recombination in each region is comparable, A o is somewhere in-between. At short circuit,
equation (3.150) becomes
and at open circuit, it becomes
I SC = I ′ SC − I o(e qI SCR S /A o kT − 1) − I SC R S /R Sh (3.151)
0 = I ′ SC − I o(e V OC/A o kT − 1) − V OC /R Sh . (3.152)
When log(I SC ) is plotted versus V OC (where I SC and V OC are obtained over a range of
illumination intensities), there is typically a regime where neither the series nor shunt
resistances are important, as illustrated in Figure 3.24. The slope of this line will yield
the diode ideality factor A o , while the y-intercept will give I o . In the regime where only
series resistance is important, equations (3.151) and (3.152) can be combined to give
I SC R S = A okT
q
[
Io e qV OC/A o kT ]
− I SC
ln
I o
(3.153)