Numerical Simulation Of Convection And Radiation Compound Heat Transfer Of Solar Cell Glass Plate

In recent years the manufacture and application of thin film batteries are developing very fast. CIGS cell is widely concerned by the international PV community with advantages of low-cost, stable performance, resistance to strong radiation, high efficiency of absorption and conversion. CIGS solar cell is a kind of high-efficiency thin film solar cell based on copper-indium-gallium-selenide absorber layer. In the production process of a certain type CIGS photovoltaic cell, the preparation of absorbing layer on glass plates is operated in a kind of convective and radiant heat-treating furnace called diffusion furnace, which relates to some important issues like the homogeneity of glass plates’heating and stress-strain of plates. Currently the research of photovoltaic cell is mainly focused on the chemical preparation and crystal analysis of absorption layer, while the impact of glass plate on the furnace heat treatment process is less researched. In this paper, the flow field distribution and heat transfer feature of the heat treatment furnace are researched by numerical simulation, and the heat flux composition of plates is analyzed. Whether the warping deformation of plates will occur at the end of the heat treatment is judged by finite element stress-strain simulation of thermal-structural coupling plates. The results show that the outmost plate has serious warping deformation which can verify the judgment and consistent with actual production phenomenon. In the end improvement measures are proposed and verified.The flow field in the heat treatment furnace is researched by numerical simulation. The plates’ temperature field and heat flux on different stages of heat treatment are obtained by unsteady numerical simulation on the convection-radiation coupling heat treatment in the furnace. The results show that the outmost plate is heated mainly by radiation. Two sides of the outmost plate are heated unevenly and there is temperature gradient on the thickness direction. Plates on the inside are heated mainly by convection and balanced as well. The heating mechanisms are obviously different between the outmost and inside plates. Temperature stress of the outmost plate is analyzed which can be judged that it will cause warping deformation.The finite element stress-strain simulation of thermal-structural coupling plates is computed which can simulates the unsteady stress-strain condition of plates. The deformation results are consistent to the judgment and the actual production phenomenon. In order to improve the uniformity of heating progress and deformation problem, the low emissivity glass is used to substitute quartz glass and simulate the furnace heating progress again. The results show that the temperature difference between plates decreases obviously. The outmost plate’s thickness temperature gradient and deformation both decrease obviously which means that the uniformity of heating progress increases a lot.An experiment is implemented to validate the non-gray radiation model used in simulation. An oven combining convection with radiation heat transfer is designed to conduct an infrared radiation heating experiment which involves quartz glass and float glass. The results show that the temperature curves of heated glass are basically consistent between experiment and simulation which can verify the reliability of the radiation model used above.