Investigation of the reverse biasing of solar cells in a space array

The investigation of the reverse bias tolerance of a solar cell in a string is performed for cell types used on current designs of British Aerospace satellites. The test schedules used were chosen to represent worst-case reverse bias conditions due to shadowing, array switching, or fracturing of cells. Certain cells showed variations in magnitude of reverse current during the course of the test period. Some cells also showed a history effect, leading to difficulties in the long-term predictability of cell behavior. It is concluded that it is not satisfactory to base estimates of the effects of reverse biasing on cell characteristics measured over the very short time periods normal for automatic measurement systems. Some cell designs appear to have inherent instability in reverse bias, which shows itself only in measurements carried out over time periods of minutes or longer