n-Type High Efficiency Bifacial Silicon Solar Cell with the Extremely High Bifaciality of 96% in Average Fabricated by Using Conventional Diffusion Method

Abstract

In this paper, we report our latest progress of n-type bifacial cell. The bifacial cell is made of 156x156mm n-type Cz-Si wafer and fabricated by almost the same process as that of conventional p-type cell. We have produced the bifacial cell in mass-production level and the cell shows the efficiency of 19.4% and high bifaciality of 96%, e.g., rear side efficiency of 18.6%, in average. By the improvement of the cell with both selective phosphorous diffusion and ALD-AlOx passivation, the efficiency of 20.16% and the bifaciality of 95% are achieved. This improvement is confirmed to be easily added to mass-production. The field test using the bifacial module shows the output gain of around 20% compared with the monofacial module. This is caused by the incident reflected and scattered light from the rear side of the system.