FE approach to determine the effect of delamination in power electronic modules for automotive applications

This paper proposes a finite element (FE) approach to assess the damage propagation by numerical simulation. With the exponential increase in the usage of power electronic (PE) components, efficient methods to determine the reliability of such modules are necessary. During operation, the modules are subject to electro-thermo-mechanical stresses that lead to the failure of the components. Implementing predictive health management (PHM) can increase the reliability of these modules. If the respective parameter exceeds the relevant threshold value, the impending failure can be detected early enough to carry out the necessary maintenance beforehand. As part of the application of a PHM system, the approach focuses on the implementation of an FE modelling concept for representing the delamination effects at the solder interface of the PE module. The increase in chip temperature and the resulting change in the voltage drop across the power transistor are obtained by numerical simulation. The respective failure levels are 20% increase in thermal resistance (Rth) and 5% increase in drain-source voltage (VDS). Based on these benchmarks from the AQG 324 standard, simulation results are calibrated with experimental results. The simulation results enable the determination of the current state (SoH). The application of input current as a loading condition, coolant temperature as an environment condition, and progression of delamination as a damage condition on the output junction temperature is considered during the FE analysis.