Thermal/Mechanical Characteristics Simulation Analysis of Solder Layer Damage in IGBT Modules

The insulated gate bipolar transistor (IGBT) is widely applied in industrial fields such as rail transit, wind power generation, smart grids, and renewable energy. The temperature distribution, stress variation patterns, thermal performance, and modeling damage in the solder layer of IGBT modules under thermal and stress loadings have rarely been studied. This study first established a three-dimensional geometric model based on the actual dimensions of the IGBT module. A finite element model was successfully constructed for thermal/mechanical multi-physics coupled simulation based on the ANSYS Workbench platform to simulate the temperature, deformation trends, and stress distribution patterns of the solder layer in the IGBT module. Secondly, the solder layer defects of the IGBT module were categorized into five major types, and 37 sets of 3D models of IGBT with damaged solder layers were designed, followed by thermal/mechanical coupled simulation analysis for each. Finally, the influence of the void positions, sizes, and distribution types in the solder layer on the module temperature, heat dissipation path, and thermal stress was simulated during thermal cycling. The results showed that the highest stress at the edge of the solder layer is 6.2504 × 10⁷ Pa, the lowest junction temperature is 70.79 °C, and the average thermal stress is 1.2388 (m/m). The highest junction temperature reached 72.562 °C under central solder layer damage states as determined by a thermal/mechanical coupled simulation analysis of four different types of solder layer defects. This research provides a theoretical basis and reliable technical support for the anti-damage and failure of IGBT modules and high-power devices.