Environmental Engineering Reference
In-Depth Information
Figure 4.29
Parallel Connection of
n
Solar Cells
(4.65)
(4.66)
A parallel connection of cells is significantly less susceptible to partial shading,
and problems associated with cell damage are much less likely.
Large solar generators often use modules with parallel cell strings of
multiple series-connected solar cells. However, parallel bypass diodes must
also secure cell protection for these modules. So-called serial-connected
blocking diodes
will protect cell strings; however, because of their high
permanent diode losses and low protective action, they are used in only very
few cases.
Technical data of solar modules
Table 4.6 summarizes technical data for selected solar modules. To point out
differences in module technology, some modules are included that are no
longer available.
This table contains three modules with monocrystalline cells, one with
polycrystalline, one with amorphous and one with copper indium diselenide
(CIS) solar cells. All modules have only series-connected cells. MPP power and
efficiency are given for standard testing conditions (see section on 'Further
electrical solar cell parameters', p136). The module efficiency is always lower
than the theoretical cell efficiency since the module contains inactive areas
between the cells. The module efficiency of the BP module is 13.5 per cent,
whereas the efficiency of a single cell is 16 per cent. Almost all modules only
have two bypass diodes; only a few modules contain a higher number of bypass
diodes.
