Thermal Residual Stress Analysis of Soldering and Lamination Processes for Fabrication of Crystalline Silicon Photovoltaic Modules

Abstract

In this study, we developed a finite element model to assess the residual stress in the soldering and lamination processes during the fabrication of crystalline silicon (Si) photovoltaic (PV) modules. We found that Si wafers experience maximum thermo-mechanical stress during the soldering process. Then, the Si solar cells experience pressure during the process of lamination of each layer of the PV module. Thus, it is important to decrease the residual stress during soldering of thin Si wafers. The residual stress is affected by the number of busbars, Si wafer thickness, and solder type. Firstly, as the number of busbars increases from two to twelve, the maximum principal stress increases by almost a factor of three (~100 MPa). Such a high first principal stress can cause mechanical failure in some Si wafers. Secondly, thermal warpage increases immediately after the soldering process when the thickness of the Si wafers decreases. Therefore, the number and width of the busbars should be considered in order to avoid mechanical failure. Finally, the residual stress can be reduced by using low melting point solder. The results obtained in this study can be applied to avoid mechanical failure in PV modules employing thin Si wafers.

Improvement in the reliability of crystalline silicon solar cell interconnection by using Nickel Micro-Plating Bonding (NMPB) technology

“…7) Chen et al 8) reported that the increasing soldering temperature causes bow and residual stress increase, and increasing residual stress may cause damage in the region of the wafer near the electrode. Also, it was concluded by Shin et al 9) that Si wafers experience maximum thermomechanical stress during the soldering process. Then, the Si solar cells experience pressure during the process of lamination of each layer of the PV module.…”

An Overview of the Photovoltaic Industry Status and Perspective in China

“…Such as Europe: 1.2-1.4 times; the United States and India: > 1.4 times; Japan: 2 times. Appropriate ratio of DC/AC can increase the economical cost of the entire PV power station and reduce LCOE [31]- [33].…”

Computational Study on Surface Bonding Based on Nanocone Arrays

“…Surface bonding is an essential step in device manufacturing and assembly, providing mechanical support, heat transfer, and electrical integration. Traditional surface bonding techniques in electronic assembly strongly rely on high-temperature processes such as reflow soldering, which can lead to undesirable thermal damage, toxic solder materials pollution, and residual stress at the bonding interface [ 1 , 2 ]. Besides, thermo-compression is another widely used bonding approach because it provides intrinsic interconnections and excellent bonding strength.…”