Aluminum Ultra-Conductors for Energy-Efficient Grid Applications

Aluminum alloys are widely used in power distribution networks for where losses due to intrinsic resistivity vary between 6-10%. While previously copper was used, of late, aluminum conductors are being used in electric motors and busbars in aviation and EVs in the transportation sector owing to the renewed interest in lightweighting. Despite being only 65% as conductive as copper, aluminum is approximately twice as light and six times cheaper than a copper wire of equivalent resistance. There is a great benefit in enhancing the electrical conductivity of aluminum to create a more efficient power transmission infrastructure to accommodate electrification-driven energy needs.

In this talk, we discuss the development of aluminum ultra-conductors, a new paradigm in energy efficient materials. Ultra-conductors are an emerging class of composite materials with nanocrystalline carbon additives (such as graphene or carbon nanotubes) in small quantities embedded in a metal substrate. Ultra-conductors demonstrate higher electrical conductivity at operating temperatures compared to the metal substrate., including the shear assisted processing and extrusion (ShAPE) technology. We describe the approach taken to achieve AA1100/graphene composites with ~7% higher electrical conductivity and >13% decrease in temperature coefficient of resistance, a measure of electrical performance at elevated temperatures, using shear extrusion in this presentation. We discuss the effects of manufacturing conditions, additive types, and additive content on the electrical properties of the composites. We introduce the science of ultra-conductors by examining the composite behavior at atom-to-mesoscales using multi-modal microscopy and density functional theory simulations. We present the different strategies used to manufacture aluminum ultra-conductors and the potential to scale them up to industrially relevant volumes for adoption in grid and transportation applications.