Abstract This study evaluates the impact of intermetallic compound (IMC) thickness on thermo-mechanical reliability of lead-free SnAgCu solder joints in crystalline silicon solar cell assembly with regard to fatigue life. Finite element modelling is used to simulate the non-linear thermo-mechanical deformation of the joints. Five geometric models of solar cell assemblies with different IMC thickness layers in the range of 1 to 4 μm are utilized. The models were subjected to accelerated thermal cycling from 40 °C to 85 °C employing IEC 61215 standard for photovoltaic panels. Creep response of each of the assembly's solder joints to the induced thermal load were simulated using Garofalo-Arrhenius creep model. Simulation results indicate that when IMC thickness grows incrementally to 1, 2, 2.5, 3 and 4 μm, thermo-mechanical fatigue life of solder joints diminishes to 13,800, 11,800, 10,600, 9400 and 7800 cycles to failure respectively. Thus, solder joint fatigue life decreases as the IMC thickness increases during service lifetime. Therefore, proper design of solder joint in crystalline silicon solar cell assembly must include consideration of IMC layer thickness to prevent premature failure and to ensure fulfilment of desired functional lifetime of 13,688 cycles to failure (25 years).

中文翻译：

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金属间化合物厚度对太阳能电池组件焊点热机械可靠性的影响

摘要 本研究评估了金属间化合物 (IMC) 厚度对晶体硅太阳能电池组件中无铅 SnAgCu 焊点热机械可靠性的影响，包括疲劳寿命。有限元建模用于模拟接头的非线性热机械变形。使用了具有 1 至 4 μm 范围内不同 IMC 厚度层的太阳能电池组件的五种几何模型。根据光伏面板的 IEC 61215 标准，这些模型经受了从 40 °C 到 85 °C 的加速热循环。使用 Garofalo-Arrhenius 蠕变模型模拟每个组件焊点对感应热负载的蠕变响应。仿真结果表明，当 IMC 厚度逐渐增加到 1、2、2.5、3 和 4 μm 时，焊点的热机械疲劳寿命分别减少到 13,800、11,800、10,600、9400 和 7800 次循环失效。因此，焊点疲劳寿命随着 IMC 厚度在使用寿命期间的增加而降低。因此，晶体硅太阳能电池组件中焊点的正确设计必须考虑 IMC 层厚度，以防止过早失效并确保实现所需的 13,688 次失效循环（25 年）的功能寿命。