Research On The Welding Stress Of Automatic Welding For Crystalline Silicon Solar Cells

As the development of society the demand for energy sources is increasing. In the last100years the consumption of energy is rapid increasing.And the non-renewable energy isbecome less and less. Therefore the develop of renewable energy sources is very urgent.Solar energy is the biggest share of renewable energy. Photovoltaic is the best way to usesolar energy. The solar cell is the core component of Photovoltaic. Crystalline siliconwafers is most widely use in solar cell. Welding process is the core part of solar modulesproduction. Thermal stress and residual stress generated during the welding process, andthey will affect the rate of breakage of wafer and the solar modules life. Research thermalstress and residual stress during the welding process have meaning to improve automaticwelding equipment.The article first analysis of the wafer welding process. First, understand the physicalproperties of silicon wafer and copper ribbon. Then analyze the welding process andwelding principle. Understand the effect of preheat temperature, soldering temperature andwelding time.Second, Study the heat transfer and thermal stress during weld. Found that the maincause of thermal deformation and stress is uneven distribution of temperature.Then solvethis problem by perheating the silicon cell.For the case of wafer excessive deformation or breakage. We analysis stressdistribution by finite element modelling. Then discuss how will different regions of weldingaffect residual stresses. Analysis the residual stresses under different welding temperatureand different copper ribbon. At last we got the suitable regions of welding, weldingtemperature and copper ribbon.Last，Do experiments of the automatic welding equipment. Verify the optimizationmeasures mentioned in the paper.