knjiga solarna energija dobra

104 THE PHYSICS OF THE SOLAR CELL
4.0
3.5
R Sh very large
3.0
V/R Sh
R Sh = 2 Ω
2.5
Cell current
[A]
2.0
1.5
R Sh = 0.2 Ω
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 3.23 Effect of shunt resistance on the current–voltage characteristic of a solar cell (R S = 0)
and a plot of I SC versus log[I o e qV OC/A o kT − I SC ] will then permit R S to be extracted
from the slope of this line. Similarly, in the regime where only R Sh is important,
equations (3.151) and (3.152) can be combined to give
V OC
R Sh
= I SC − I o e qV OC/A o kT
(3.154)
and R Sh can be determined from the slope of the line given by plotting V OC versus
[I SC − I o e qV OC/A o kT ]. If the series and shunt resistances are such that there is no regime
where they can be neglected, the parameters can, with patience, be extracted through the
process of trial and error.
3.5.4 Temperature Effects
From equations (3.127) and (3.128), it is apparent that
I o1,n ,I o1,p ∝ n 2 i (3.155)
and from equation (3.129) that
I o2 ∝ n i . (3.156)