21.4% efficient SMART mono-Si PERC solar cells with adapted firing process for LeTID mitigation

We have developed a fast firing oven (FFO) firing profile that mitigates light and elevated temperature induced degradation (LeTID) in boron doped passivated emitter and rear cells (PERC), made from high-performance multicrystalline silicon (lip mc) and mono-cast material. During LeTID testing, the highest degradation in relative efficiency in the samples fired with this profile is only -2%(rel) < Delta eta < -1%(rel) depending on the cell, compared to -5%(rel) < Delta(eta) < 6%(rel) in samples fired with the standard profile. To show that the benefit of this technique can be transferred to modules, the influence of the temperature profile during lamination was investigated. The effect of LeTID mitigation persisted after the simulated lamination process. This new firing profile did not significantly influence the initial efficiencies of the cells that have been fired with it compared to samples fired with a standard firing profile (-0.2%(abs) 更多