Preparation Of Glass Powder In Front Silver Paste Of Solar Cell

With the development of social economy and human’s increasing demand for energy, the limit of fossil energy and its damage to the environment after using cause the attention from people. The development and utilization of clean and environmental protection renewable energy has become the main trend of future, because of its wide coverage and the advantages of inexhaustible speciality, solar energy cause the attention of energy scientists around the world. This paper bases on the glass powder used on front silver paste of solar cells as the research object. Regard product quality, economic benefit and environmental protection as consideration, prepared the PbO-SiO2-B2O3glass powder and PbO-Bi2O3-SiO2-B2O3powder, and successfully apply them to the production of solar cells positive silver paste. During the process, the milling process of glass powder was optimized. The influence of glass composition on its softening temperature was studied by DSC; The effect of glass powder softening temperatureon on the properties of paste and battery was studied by the four point probe tester and the solar cell analyzer, obtained the glass powder formula of best performance. The effect on properties of past by glass powder of different concentrations was studied by SEM and four-point probe tester, and achive the paste of best formula. To get the best sintering process, the effect of sintering process(peak sintering temperature and sintering time) on the cell performance is studied. The results of the study are as follows:First, the optimum milling process parameters for glass powder: milling time18h, the ratio of grinding ball and material1:1, the match level of grinding ball6:4:1, the speed of grinding machine400r/min. The average particle size of glass powder by this process conditions is2.3um, meet the requirements of the solar cell positive silver paste.Second, for PbO-SiO2-B2O3glass powder, the lower softening temperature of glass powder, the stronger adhesion of sintered membrane. Softening temperature of glass powder is455.0℃, sintered membrane of polycrystalline silicon solar cell positive silver paste has the higher density, its adhesion can be up to4.5N, satisfies the requirement of industrial. The ratio of height to width of thin grid line is0.256, has the lower solar cell series resistance0.09Ω, the higher photoelectric conversion efficiency17.32%. Softening temperature of glass powder is better at this time, the formula of glass powder is28wt%PbO-64wt%SiO2-8wt%B2O3; For PbO-Bi2O3-SiO2-B2O3glass powder, sintered membrane prepared by the glass powder whose softening temperature is the451.2℃in polycrystalline silicon solar cell front silver paste has the higher density, its adhesion can be up to4.8N, the resistance of sintered membrane has the lower1.25mQ.cm, at this point glass powder has the better performance, the formula is24wt%PbO-40wt%Bi2O3-28wt%SiO2-8wt%B2O3.Third, for PbO-SiO2-B2O3glass powder, its best content in front silver paste is4wt%, the best formula of silver paste is:silver powder86.5wt%, glass powder4wt%, organic carrier9.5wt%;For PbO-Bi2O3-SiO2-B2O3glass powder, its best content in positive silver paste is6wt%, the best formula of silver paste is:silver powder84.5wt%, glass powder6wt%, organic carrier9.5wt%.Forth, the front silver paste with PbO-SiO2-B2O3glass powder, its best sintering process is:sintering peak temperature860℃, sintering time120s. The sintered membrane by this sintering process has the highest density. The ratio of height to width of thin grid line is0.276, The photoelectric conversion efficiency of cells is highest, at17.79%; The front silver paste with PbO-Bi2O3-SiO2-B2O3glass powder, its best sintering process is:sintering peak temperature870℃, sintering time130s. The sintered membrane by this sintering process has the highest density. The ratio of height to width of thin grid line in front electrode is0.26. The photoelectric conversion efficiency of cells is highest, at17.65%. Compared with solar cells with front silver paste using PbO-SiO2-B2O3glass powder, solar cells with positive silver paste using PbO-Bi2O3-SiO2-B2O3glass powder has a little lower battery photoelectric conversion efficiency and ratio of height to width of thin grid line in front electrode.