Naturally-Cooled Heat Sinks for Next-Generation Battery Chargers

Abstract

High-performance heat sinks are required for next-generation battery chargers to manage their ever-increasing power density. For chargers at the now upwards-shifted lower end of the power density spectrum, manufacturers still favor naturally-cooled heat sinks for their low cost, reliability, and simplicity. This study focuses on designing high-performance naturally-cooled heat sinks with continuous, segmented, inclined, and pin fins. A systematic numerical approach in ANSYS Fluent is used to model the heat sinks in three mounting orientations: horizontal, vertical, and sideways. Proposed heat sinks were developed using relevant literature on fin geometries to improve upon a provided, finned heat sink subjected to specified boundary conditions. The provided benchmark suffered from orientation-dependent performance, exhibiting its highest wall temperatures when installed sideways. Although intended to improve convective performance in the vertical orientation, fin segments marginally changed wall temperatures in this orientation. Instead, they considerably lowered them in the sideways orientation. The presence of gap flow, allowing some buoyancy-driven flow to span the width of the heat sink, lowered the average sideways-oriented wall temperature by about 3% compared to the benchmark. An arrangement of staggered pin fins furthered this improvement with a 5% drop in the average sideways-oriented wall temperature compared to the benchmark, albeit increasing the vertical orientation’s average wall temperature by about 2%. Our future work will look to gather experimental data for the specified heat sinks and boundary conditions.