High efficiency solar cells obtained from small size ingots with 30 cm#x03A6; by controlling the distribution and orientation of dendrite crystals grown along the bottom of the ingots

摘要

We have obtained high-efficiency solar cells using 15.6 cm x 15.6 cm size wafers cut from small Si multicrystalline ingots with 30 cmØ and the height of 7.5 cm, as well as those using 10 cm x 10 cm size wafers [1]. The ingots were grown by controlling the distribution and orientation of dendrite crystals grown along the bottom of the ingots, using the dendritic casting method. The conversion efficiency η of solar cells using the Si wafers was around 17.7 %, and the conversion efficiency was kept high and constant even in a large part (60% for more than η=17% and 80% for more than η=16%) of the small ingot. Therefore, we have made a plan to design and manufacture a large-scale equipment for industrial applications because much high efficiency and high yield can be expected using the large-scale equipment.