|Materials and Thermal Management I
Advanced materials in thermal management have historically been found in niche applications in aerospace and defense related electronics, and specialized applications like RF power transistors. Here MMC materials like AlSiC and CuW with tailorable CTE come to mind. A challenge has been to develop these materials for commercial, mass-market applications, which relies on reducing manufacturing cost while proving to be essential to the application. We have often found clever thermal management engineers develop solutions that obviate the need for expensive advanced materials, as a product matures from niche or specialty into mass market. High thermal conductivity is one of the properties of the new wonder material, graphene, but practical application could prove to be challenging. In addition to the heat sink or heat spreader, thermal interface materials also play an important role in thermal designs. They are polymeric based compliant materials. The heat pipe and its “vapor chamber” cousin are important tools for thermal management that provide much higher thermal conductivity than solid state materials, and the devices have important materials technology in the form of wicking materials. We also note that “cleantech” is behind a lot of new products that require innovation in thermal management: two notable examples are power electronics for HEVs and EVs, and LED lighting. The HEV application is more mature and has seen a notable evolution in the design of the power electronics modules. The first HEVs from Toyota used expensive CuMoCu baseplates as heat spreaders. LED lighting requires innovation in thermal solution, preferably without active cooling, and low cost is essential if it is going to evolve into a mass-market lighting device. In addition to materials, the newsletter also looks at some thermal management engineering developments.