HIGH-EFFICIENCY SOLAR CELLS WITH LASER-GROOVED BURIED CONTACT FRONT AND LASER-FIRED REAR FOR INDUSTRIAL PRODUCTION

摘要

The laser-grooved buried contact (LGBC) cell produced by BP Solar combines the advantages of a selective emitter and a fine line grid structure on the front. A solar cell with such a front structure is well capable of 20% efficiency on monocrystalline silicon. The current rear metallization in the production process is a full area aluminium back surface field. Although of high quality, the internal reflectance and rear surface passivation can be improved to increase cell efficiency. An industrially viable process for the rear surface of high efficiency cells is the laser-fired rear contact process (LFC) in which aluminium is fired through a dielectric passivation layer. The two laser technologies LGBC and LFC are combined into a single cell structure and applied to monocrystalline silicon. Solar cells with 19.8% efficiency were achieved on 108 cm~2 large FZ silicon of 0.5 Ω cm base resistivity.