Fujitsu Laboratories Develops Pure Carbon-Nanotube Sheets

Fujitsu Laboratories Ltd. announced the successful development of a high-thermal-conductive carbon-nanotube sheet with the world’s top heat dissipation performance. The sheet is composed of pure carbon nanotubes, oriented perpendicularly, resulting in exceptional thermal conductivity and heat resistance.

The rapidly growing prevalence of electric vehicles has created demand for onboard power modules to control high-voltage electric power with low power demands of their own and high breakdown voltage, while at the same time needing to maintain reliability despite the high-temperature operations that come with compact modules. Silicon carbide (SiC), which has low power consumption and a high breakdown voltage, is being used as an alternative for silicon, but in order to operate reliably at temperatures of 200°C or higher, heat needs to be removed efficiently from SiC devices.

Fujitsu Laboratories has now developed a process for manufacturing carbon nanotubes, a material known for its high thermal conductivity in a cylindrical structure, and in which the combination of process temperature and pressure is precisely controlled to grow dense, uniform arrays of perpendicularly oriented carbon nanotubes. In order to be used for removing heat from SiC power modules, Fujitsu Laboratories has also developed a sheet-forming technology in which oriented-growth carbon nanotubes are subjected to heat treatment at temperatures above 2000°C, creating sheets that are easy to transport. Heat-dissipation sheets made using these technologies have about three times the heat-dissipation performance of existing materials made using indium, and have been found to have the world’s best heat-dissipation performance among carbon-nanotube sheets.

Fujitsu Laboratories plans for this technology to be used in automotive heat-dissipation materials from fiscal 2020, and is considering to expand business into new areas, such as in applications for next-generation high-performance computing and telecommunications equipment.

Details of this technology were presented at the 2017 Workshop on Innovative Nanoscale Devices and Systems (WINS2017) in Hawaii from November 26 through December 1.