Crystalline Silicon Solar Cells Screen Printing Process Optimization And New Exploration Research

Solar cell fabrication processes contain surface texturing, PN junction doping,edge isolation, PSG cleaning, PECVD coating, screen printing and firing. The screenprinting metal electrode is mainly responsible for collection and conduction of thephotocurrent, plays an important role in improving the cell electrical performance andcontrolling the solar cell production costs.This thesis is focused on the design of the grid line patterns, optimization of thescreen printing process, and the exploration of new technology, the main contents:First, based on an improved diode-series resistance model, Theoretical study thegrid line patterns influence the series resistance and conversion efficiency of solar cell,looking for optimization of the law for the follow-up screen printing optimization andexploration of new technology to provide a theoretical basis.Then, looking for the parameters of screen printing and net matching with thepaste, based on these, to optimize the grid line width, and get the equivalent cellefficiency of60line width of290mesh and400mesh70line width, the former fastprinting speed, but a large consumption of paste, the latter under the premise of theexpense of a certain output can be reduced to17.2%of the each piece of silver pasteconsumption; and then based on the production line of the grid line patterns, thecomparative study of the closed loop grid line and different bus bars, draw three busesand closed loop grid line design can enhance the ability of the grid line collection andconduction current; debugging of the sintering temperature, low corrosive pastecombine60Ω/sq and70Ω/sq sheet resistance the cell efficiency increase~0.1%and0.2%respectively comparing with production line.Finally, based on the problems of screen printing technology, we explore the newtechnology(laser doped selective emitter and electroplating processes), get the solar cellclose to the efficiency of the production line, and enhance short-circuit current densityby2.56%, laying the foundation for further optimization of the new process.