Highly efficient litz wire by fluorination of graphene or carbon nanotube yarn

Abstract

Yarns for electrical conduction that comprise a composite of fibres composed of carbon nanotubes and/or of a multiplicity of graphene layers and have a specific porosity are already known. The yarns have an electrical insulation layer, which is produced by application of a polymer coating. The electrical insulation layer has to adhere to the yarn sufficiently well for the insulation not to detach even in the event of mechanical stress, for example deflection with a small bending radius. Furthermore, the electrical insulation layer should be as thin as possible in order to achieve a low thermal resistance. Additionally, the electrical insulation layer has to be elastic enough to be able to cope with any geometric changes in the non-rigid yarn without detaching. In the electric conductor according to the invention, the electrical insulation is improved. The invention provides for the outer fibres of the composite to be fluorinated in such a way that they form an electrical insulation layer (2) and for the fibres in an internal region (3) to be electrically conductive.