Notably, NEC has already released a smartphone, the Medias X06E, which uses a heat pipe.
Since the conventional graphite plus foil cooling method is no longer able to dissipate enough heat in modern smartphone models efficiently, after 4G becomes a common transmission specification for smartphones in the future, the heat problem is only expected to become worse. The heat pipe in NEC's smartphone has a diameter of only 0.6mm, far smaller than ultrabook heat pipes' 1-1.2mm, allowing the heat pipe to fit into smartphones' limited space.
Heat pipes contain a liquid that turns into a vapor when coming into contact with a hot interface. The vapor then travels along the heat pipe to the cold interface, condensing back into a liquid, and releasing the latent heat. [More]
Several cooling module players are developing 0.6mm heat pipes; however, yield rates are currently at 30%. They are working aggressively to improve these rates so that their heat pipes can be used in production.