Study On Preparation And Properties Of Photovoltaic Ribbon

As a highly efficient clean method of power generation, the study on photovoltaicmaterials and photovoltaic technology has been the research hot-spot. PV ribbon is the criticalsolar cell components, of which the properties are very important to the property of solar cellmodule. In this paper, tensile testing, scanning electron microscope(SEM), Energy DispersiveX-ray(EDX) were adopted to further investigate the impact of hot-dippingparameters(hot-dipping temperature and hot-dipping speed) on the microstructure andthickness of the coating. The effect of heat-treatment on surface microstructure andmechanical properties of PV ribbon were researched.The experimental results indicated that hot-dipping temperature and speed are twocritical factors which affect the properties of hot-dipping PV ribbon’s coating. For PV ribboncoated with Sn63Pb37, in higher temperature, hot-dipping is not suitable for acquiring smoothsurface. In lower temperature, except some handful short rodlike and globular Pb-rich phase,other Pb-rich phases are wider and shorter. The variation of hot-dipping temperature did notinfluence much on the distribution of the microstructure of the coating. When the temperaturewas high, the difference of the two sides of the thickness of the Copper ribbon coating wasbigger, and the thinner coating was less than10μm. When the temperature was low, thedifference of the two sides of the thickness of the Copper ribbon coating was smaller, and thethinner coating was thicker than10μm. So the low temperature is more suitable for acquiringPV ribbon with appropriate coating thickness. When the speed was very slow, the surface ofribbon was not smooth and with obvious heaves, moreover the sizes of the grains were notuniform. When the speed was normal, the surface of ribbon was smoother and with moreuniform organization. Mechanical properties of PV ribbons coated with tin-lead(Sn63Pb37) and lead-freesolders(Sn3.0Ag0.5Cu and Sn3.5Ag). The experiment results shows that lead-free PV ribbonhas achieved the higher tensile strength but lower elongation then tin-lead PV ribbon.SAC307was hot-dipped in N2environment(245℃) with20ppm of O2. Then it was tensiletested in room temperature with tensile rate50mm/min, the results was: tensile strength156.48MPa, elongation62.75%. Because of the presence of inert gas, the hot-dippingtemperature was reduced by a large margin and it did no damage to the mechanical properties.And there was no obvious debonding near the tensile fracture. The gap between coating andCopper ribbon was very close, which indicated exploiting inert gas in hot-dipping couldimprove binding force of coating and Copper ribbon. Even when the hot-dipping temperaturewas low, the coating and the Copper bent well. Thus it can be seen, the usage of inert gas inhot-dipping can reduce the hot-dipping temperature and improve the binding force of thecoating and Copper ribbon. Besides, with the increase of tensile speed, the strength of PVribbon increased and the elongation of PV ribbon decreased.