Page 90 - Applied Photovoltaics

same voltage! cell 2 has lower output caused by:
x manufacturing defects
1 2 x degradation (e.g. cracking)
x partial shading (e.g. trees,
V buildings, leaves, bird
droppings, discoloured
encapsulant etc.)
x higher temperature

Figure 5.2. Mismatched cells connected in parallel.

Figure 5.3. Parallel-connected mismatched cells and the effect on current. The
combined curve is determined by summing the currents I 1 and I 2 for each
voltage V.

Figure 5.4. An easy method of calculating the combined V oc of mismatched cells
in parallel. The curve for one of the cells is reflected in the voltage axis so that the
intersection point (where V 1 + V 2 = 0) is the V oc of the parallel configuration.

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