Preparation And Performance Study Of Aluminum Paste Using For Crystalline Silicon Solar Cells

The rapid industrialization is consuming the fossil fuels such as oil,coal and gas rapidly while it has significantly improved people's life.Therefore,it is of great importance to seek for an environment-friendly and resource-conserving energy.There into,the solar energy holds the best prospect due to its cleaning,inexhaustibility and less-pollution.Solar cell technology is one of the technologies that can directly transform the solar energy to electric energy.Crystalline silicon solar cells are the most widely used due to their mature technology and high efficiency.Aluminum paste plays an important role in crystalline silicon solar cells.When the aluminum paste is sintered at high temperature,the aluminum is easily alloyed with silicon to form a good Ohmic-Contact,thereby improving the open circuit voltage of the solar cells,reducing the series resistance and the recombination rate of the back surface.In this paper,test methods for the performance of aluminum paste and solar cell was established.By studying the composition of the glass powder,the optimal composition of the glass powder for aluminum paste was obtained.In addition,the different particle sizes of aluminum powder in aluminum paste,the content of glass powder,the composition of organic carrier and the influence of sintering process on the performance of the battery were systemically investigated.The specific research results are as follows:(1)The mechanism of aluminum paste was analyzed by researching the producing process of solar cells.The effects of aluminum powder,glass powder and organic carrier in aluminum paste were also analyzed by studying the composition and preparation process of aluminum paste.In order to research the performance of aluminum paste and solar cells,a comprehensive test platform for solar cell's performance was established,including the viscosity and solid content of aluminum paste,the square resistance and efficiency of the solar cell.(2)The composition of the glass powder was optimized by changing the proportion of the glass powder component.Basing on the analyses of softening point of the glass powder that determined by DSC,the state of the glass powder that analyzed by XRD as well as the adhesion tensile,the composition of the glass powder and the optimum content are determined as B₂O₃:45%,Zn O:35%,Si O₂:4%,and Bi₂O₃:16%.The optimum sintering temperature is 1100°C,which was beneficial to the formation of a stable network structure of the metal oxide lattice,forming a glassy state.In addition,the optimal ball milling time is determined to 4h.When the particle size of the glass powder is reduced to a suitable range,it contributes to the co-dissolution of aluminum and silicon.(3)The ratio of small-sized aluminum powder to large-sized aluminum powder in aluminum powder was determined as 30%to 70%by compounding of aluminum powders with different particle sizes.The optimum content of glass powder in aluminum paste was determined to be 3%by researching the effect of glass powder's proportion on the performance of aluminum paste and solar cells.The composition of the organic carrier in the aluminum paste was researched by investigating the printing performance of aluminum paste.The effect of different sintering temperatures on cell efficiency and appearance was investigated by varying the sintering temperature.Increasing the sintering temperature increases the thickness of the P+layer,which may also cause high warpage and appearance problems,and the sintering temperature is preferably 795°C.