Degradation of crystalline silicon solar cells caused by lightning induced impulse surge

Abstract Crystalline silicon (c-Si) solar cells are connected in series to form photovoltaic modules, which are installed in wide-open areas. They are exposed to lightning electromagnetic (EM) interference at high risk. The lightning EM field can induce an impulse surge in the loop of the solar-cell string, and c-Si solar cells are prone to damage. To study the effect of lightning surge on monocrystalline silicon cells and polycrystalline silicon cells, impulse voltage tests are conducted. Semiconductor structures of c-Si solar cells after testing are observed using scanning electron microscopy. The results indicate that the lightning surge will generate some cracks and defects in the P–N junction. Under a strong electric field, the N-type emitter layer and the grain boundary can be destroyed, which contributes to the degradation of the c-Si solar cell. Compared to monocrystalline silicon cells, polycrystalline silicon cells can withstand greater forward lightning surge; however, their maximum reverse lightning surge is relatively low.