Analysis model for thermal resistance of double-sided cooling power module with pin-fin heat sink used in xEVs

This study proposes a modeling process for conveniently analyzing the thermal resistance of a double-sided cooling (DSC) power module used in automotive inverters. Conventionally, circular-shaped pin-fins are adopted in the heat sinks used in DSC modules. This study utilizes finite element method (FEM) simulation to estimate the junction-to-fluid thermal resistance and compares the simulation results with measured values. The modeling process achieves high accuracy, approximately 97%. The analysis involves an optimized design of the circular pin-fins, exploring parameters such as pin-fin spacing and diameter size. This optimization results in a sufficiently low device junction temperature while maintaining an acceptable pressure drop. Furthermore, the developed model is applied to two uncommon pin-fin shapes, cone and oval, and their performance is evaluated. The oval-shaped pin-fins reduce the device temperature by approximately 6.7%, from 156.2 to 145.7 celcius, with a slight increase in pressure drop from 2.18 to 2.92 kPa. However, this pressure drop is low enough to supply coolant to a xEV cooling system. These findings enhance the accuracy of thermal resistance analysis for DSC power modules and offer a cost-effective means of estimating results without the need for direct manufacturing and measurement of pin-fin shape changes.