Performance Demonstration of a Dropwise Vapor Chamber for Highly Efficient Heat Spreading for Power Electronics

Efficient heat spreading is crucial for thermal management in high-power electronics. Dropwise vapor chambers (DWVC) utilize dropwise condensation and eliminate the condenser wick, which significantly improves the heat-spreading. In this study, a highly efficient DWVC was presented by integrating a non-wetting graphene surface. The working mechanism of DWVC was demonstrated via visualization and a prototype was experimentally investigated. Owing to dropwise condensation, two liquid return mechanisms were observed in the visualization. The DWVC prototype dissipated 256 Wheat (~41 W/cm
²
) in experiment with the hotspot temperature at 88 °C. Overall, a 30%-50% thermal resistance reduction was achieved compared with the commercial vapor chamber, which is ~1/3 of the thermal resistance of pure copper with the same dimensions but 42 % lighter. Three orientation angles were tested and only a small elevation of thermal resistance was observed at 90°. Last, the improvement and optimization of DWVC planned for future work were discussed.