One problem to be faced when using thinner polycrystalline silicon wafers is the composite of the surface and the material quality of the base region. It has been experimentally confirmed that when SiNx is used as the front surface passivation layer and Al is used as the back surface field (BSF), when the thickness of the polysilicon sheet is more than 200 um, the thickness of the Jsc and the thickness of the silicon wafer are independent of each other, and only the thickness of the silicon wafer is less than 200 um, Jsc. It decreases as the thickness decreases. BSF can hinder the movement of the photogenerated minority to the back surface and reduce the back surface recombination, which is beneficial to the collection of carriers by p/n junction. When the thickness is low, the absorption of incident light by the substrate is reduced, and the influence of BSF on the short-circuit current density of the solar cell is more obvious. SiNx as a front surface passivation layer can reduce surface recombination and improve the quality of the base material. However, when the thickness of the silicon wafer is very low, very low and low energy photons will pass through the silicon wafer and cannot be absorbed, and the Jsc will have a tendency to decrease. Second, the influence of the thickness of the silicon on the open circuit voltage Voc When AL-BSF is used on the back side of a polycrystalline silicon solar cell, if the thickness of the silicon wafer is greater than 200 um, the open circuit voltage Voc is independent of the thickness of the silicon wafer. When the silicon wafer is relatively thick, the Voc and the thickness of the silicon wafer are independent of each other. Third, the influence of silicon wafer thickness efficiency When the thickness of the silicon wafer is greater than 200 um, the efficiency of the polycrystalline silicon solar cell using AL-BSF is independent of the thickness of the silicon wafer. For silicon wafers with a thickness of less than 200um, the solar cell efficiency of high base mass decreases with decreasing thickness, and for low base quality solar cells, the efficiency is still constant. In the standard industrial step, the 200um silicon thickness is the starting point for the performance reduction of polycrystalline silicon solar cells. When the thickness of the polycrystalline silicon wafer is less than 200 um, the main electrical parameters of the polycrystalline silicon solar cell begin to decrease. When reducing the thickness of the wafer to reduce the cost of photovoltaics, an effective surface passivation method is used to reduce surface recombination and improve the quality of the base region. Electric or pneumatic polisher has been widely used in industrial processing. It is installed in the end of Industrial Robot. Just it can not control the force flexibly. Our Force Control System, or active contact flange, Constant Force Actuator can solve this problem very well. It can improve the polishing efficiency and optimize polishing effect very well. Industrial use Electric polisher, Industrial use pneumatic polisher, Industrial use orbital polisher DARU Technology (Suzhou) Co., Ltd. , https://www.szactivecontactflange.com
First, the impact on the short circuit current Jsc