鈉鈣玻璃薄板於退火製程的熱彈塑性應力分析

Abstract

本文以熱彈塑性有限元素分析探討CIGS 太陽能電池之鈉鈣(soda-lime)玻璃基板於退火製程中產生的殘留應力。薄膜太陽能電池玻璃基板表面的CIG 塗層與氣體H2Se 的完全反應溫度約500℃以上，玻璃基板在快速升溫過程容易產生過大的熱應力。鈉鈣矽玻璃的應變點為523℃，玻璃加熱至應變點會產生不可恢復的變形，冷卻後會產生殘留應力。退火製程的殘留應力評估有助於改善製程溫度設定。數值模擬分析考慮玻璃薄板受到對稱與非對稱加熱方式及不同溫度的玻璃特性，非對稱退火加熱通常會產生較大的玻璃殘留應力，改變退火爐溫度可以有效降低殘留應力。最後，本文計算玻璃切割之表面垂直裂縫尖端的應力強度因子，評估上述退火製程的玻璃殘留應力容許值。

This thesis explores the thermal stresses and residual stresses in the soda-lime glass substrates of CIGS thin film solar cells in annealing process using elasto-plastic finite element analysis. The H2Se vapor achieves full incorporated into the CIG film deposited on the glass substrate with reaction temperatures above 500℃. Excessive thermal stress is possibly produced in the glass substrate in a rapid heating process. After annealing, permanent deformations and residual stresses will be yielded in the glass if processing temperature is over the strain point of soda-lime glass at 523℃. Assessment of the residual stress is helpful to improve setting temperature in the process.Numerical simulations took into account of symmetric and asymmetric heating configuration for glass substrate with different temperature-dependent stress-strain relations. Asymmetric heating commonly produces higher residual stresses than the symmetric process. Varying temperatures of the annealing furnaces can effectively reduce the residual stress. Finally, the stress intensity factors are evaluated for different length surface cracks perpendicular to glass plate in this study. The allowable residual stress of the glass is assessed for the above-mentioned annealing process