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

We have obtained high-efficiency solar cells using 15.6 cm × 15.6 cm size wafers cut from small Si multicrystalline ingots with 30 cm^Ø and the height of 7.5 cm, as well as those using 10 cm × 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.