Advanced Cooling of Power Electronics with Copper Cold-Sprayed Aluminum Heatsinks & Busbars

Abstract:
The recent advancement in materials and manufacturing technologies has opened new avenues for heat sink design, focusing on material selection. In the category of advanced technology, cold spray has shown enormous potential for joining different materials in the solid state. This paper presents an exciting alternative to overcome the issues associated with conventionally available copper and aluminum heat sinks by manufacturing a hybrid heat sink that combines the thermal benefits of copper with lightweight aluminum using a cold spray process. Cold spray (CS) technology is a well-established technique for handling metallic deposits in various industries. Cold spray (CS) technology is a well-established technique for metallic deposits in multiple sectors. CS process is known to deposit the powder particles in a solid state far below the melting point of the materials; as a result, common problems associated with temperatures, such as high-temperature oxidation, thermal stresses, and phase transformation, can be avoided. Moreover, cold spray offers short production times, unlimited component size capability, and flexibility for localized deposition. In recent years, CS technology has been extensively used for electrical applications, e.g., cold-sprayed copper for heat sinks, busbars, heat exchangers, and refrigeration units. The present work demonstrates the properties of cold-sprayed copper and its utilization for hybrid heat sink and busbar applications. The results illustrate that the properties of cold-sprayed Cu in the as-sprayed state are comparable with bulk-Cu with 98% IACS electrical conductivity and thermal conductivity of 368 W/mK. Perfectly gas-tight Cu-deposits with a Heleakage rate smaller than 1×10-7 mbar-l/s have been produced.