Figure 2: 1-Diode model used in this paper for representing one
individual cell in the module circuit.
I PH(φ) is the photogeneration of current in the
solar cell, which is directly proportional to the illumination intensity
φ. In the typical parameter range of well-working silicon solar cells,I PH(φ) is numerically almost identical to the
short-circuit current I SC at illumination
intensity φ. The variable I 0 is the saturation
current density, R S is the series resistance,R Sh the shunt resistance, V is the voltage
at the terminals of the solar cell, q the elemental charge,kT is the product of the Boltzmann constant k and the
temperature T . The ideality factor is specified by the variablen . Except for the photogenerated currentI PH(φ), all variables are independent of the
illumination intensity φ. The illumination intensity (or irradiance) φ
is typically given in W/m², where the standard test condition (STC)
corresponds to 1000 W/m² with an AM1.5G spectrum. We will refer to this
standard intensity in this paper as “1 Sun”, and 0.5 Sun or 0.2 Sun
refer therefore to 500 W/m² and 200 W/m², respectively.
Unless otherwise stated, the standard parameter set for the
area-specific values of the parameters in equation 1 are those listed in
Table I.
Table I: Standard set of parameter values of the 1-Diode
parameterization used in this study