太阳电池硅片ELCC技术模具温场的计算机模拟

COMPUTER SIMULATION OF THE MOLD TEMPERATURE FIELD FOR THE ELCC TECHNOLOGY

运用有限元法对太阳电池硅片电磁悬浮熔炼离心铸造（ＥＬＣＣ）技术中成形模具的稳态温度场进行了计算机模拟。模拟结果表明：当炉膛温度为１４５０℃时，在模具型腔内，中心浇口处温度最高，达到１３９０℃，边缘处温度较低，也有１３５０℃，接近硅的熔点温度；在所关心的模具型腔尺寸范围内，径向温度梯度大于３．５℃／ｍｍ，且中心浇口温度高于边缘温度，这种温度梯度分布特征有利于硅片凝固应力的及时释放，避免硅片的破裂；轴向温度梯度大于８℃／ｍｍ，这种温度梯度分布特征有利于实现硅晶粒在厚度方向上的定向生长，提高硅片的光电转换效率。

omputer simulation of the temperature field of the mold, which is used for producing the low cost solar cell silicon sheet with the Electromagnetic Levitation-melt Centrifugal Casting (ELCC) technology, is carried out with the finit element method.The simulation results show that: In the mold cavity, the highest temperature is 1390℃at the centre of the pouring mouth, and the lowest is 1350℃ at the circumference,which are both adjacent to the melting point of silicon (1420℃), when the furnace temperature is 1450℃. Within the interesting domain of the mold cavity. the radial temperature gradient is oyer 3.5℃/mm. which is helpful to the relaxation of the solidification tension for avoiding the breakdown of the silicon sheet. The axial temperature gradient is over 8℃/mm, which is helpful to the directional growth of the silicon crystals along the axial direction for improving the photovoltaic efficiency of the silicon sheet.