fujitsu laboratories (kawasaki, japan) announced in november that it has successfully developed a carbon nanotube sheet that is highly thermally conductive and has the top heat dissipation performance in the world that is targeted at electric vehicles and will replace silicon carbide (sic).

schematic of carbon nanotubes as heat dissipation sheets. (fujitsu laboratories)

according to the announcement, fujitsu developed a process for manufacturing carbon nanotubes with the correct combination of temperature and pressure to grow in “dense, uniform arrays of perpendicularly-oriented carbon nanotubes.” it also created a sheet-forming process that treats the carbon nanotubes at more than 2,000°c.

“heat-dissipation sheets made using these technologies have about three times the heat-dissipation performance of existing materials made using indium,” the announcement continued, “and have been found to have the world's best heat-dissipation performance among carbon-nanotube sheets.”

the details about the technology were presented at a nanoscale conference in hawaii at the end of november and the company is planning on using the technology for automotive heat dissipation materials beginning in 2020.

fujitsu credits two breakthroughs for developing the technology: multi-walled carbon nanotube growth control using the precise control of the metal-particle catalyst and the position of the feedstock gas inlet in relation to the substrate and multi-walled carbon nanotubes sheet formation through high heat to ensure the correct orientation.

“a carbon-nanotube heat-dissipation sheet created by this technology was found in actual measurements, with contact resistance taken into account, to have roughly three times the thermal conductance of indium sheets, an existing material known to have high thermal conductivity,” the announcement added.

“furthermore, indium sheets have a melting point of approximately 160°c, but this heat-dissipation sheet was found to have a high heat tolerance of more than 700°c. these characteristics enable the efficient cooling of power modules in advanced electric and hybrid vehicles.”