Disequilibriums in series connected solar cells - An approach to the protection by parallel diodes

The present investigation is concerned with experiments and theoretical studies which have been conducted to obtain a better understanding of problems occurring in connection with the operation of high-power arrays consisting of solar cells which are connected in series. Differences in cell characteristics and an accidental shading of a part of the surface of the modules can lead to a voltage inversion in the case of one or more cells. The lack of uniformity in operating conditions for the individual cells can produce temperatures which may exceed the maximum temperature that can be tolerated by the encapsulation. Protection can be provided with the aid of by-pass diodes. The possibility to provide each cell with a by-pass electrode has, therefore, been investigated, taking into account the feasibility to incorporate a diode directly into the silicon wafer for each cell.