激光开槽对MWT+PERC单晶硅太阳电池性能影响的研究

EFFECTS OF LASER ABLATION ON PERFORMANCE OF MONOCRYSTALLINE SILICON MWT+PERC SOLAR CELLS

金属缠绕穿透(MWT)技术和钝化发射极及背接触(PERC)技术叠加应用可获得较高的硅太阳电池转换效率,且可以降低硅材料的损耗,但不同的背面激光开槽工艺会对电池的电性能产生不同影响。在保证同批次单晶硅片的背面开槽率(2.10%)不变时,针对MWT+PERC单晶硅太阳电池工艺中的背面激光开槽工艺进行了研究。通过调节激光功率的大小来改变开槽宽度与开槽线间距的大小,从而探究不同开槽图形对MWT+PERC单晶硅太阳电池电性能的影响;同时在3D显微镜下观察不同开槽宽度时硅片表面的激光光斑质量,并采用扫描电子显微镜(SEM)观察不同开槽宽度时这类电池烧结后局部接触区域的形貌。结果表明,开槽宽度在33~35μm、开槽线间距为0.90±0.05 mm时,MWT+PERC单晶硅太阳电池的电性能及开槽形貌质量最佳。

The integration of metal wrap through(MWT)and passivated emitter and rear contact(PERC)solar cells technology has the advantages of higher conversion efficiency and lower silicon consumption.However,the different rear laser ablation processes have an impact on the electrical performance of silicon cells.The rear laser ablation process of MWT+PERC monocrystalline silicon solar cells was investigated in this experiment on keeping a constant rear laser ablation rate(2.10%).The laser power was adjusted to change both the slotted width and the spacing between slots in order to investigate the influence of different laser patterns on the electrical properties of MWT+PERC monocrystalline silicon solar cells.3D microscope was applied to observe the laser spot quality of different slotted widths and scanning electron microscope was used to observe the microscope of rear local contact area of cells after sintering process under different slotted widths.The results show that slotted width is about 33 to 35μm with the line spacing is 0.90±0.05 mm,resulting in a better slot shape and electrical properties of MWT+PERC monocrystalline silicon solar cells.