A team of scientists based at Oak Ridge National Laboratory is working on a composite that gives copper wires an enhanced capacity for electrical current, making them more efficient and power dense.
The new material would be used to make Electrical Vehicle traction motors more efficient and power dense.
The researchers want to eliminate some of the challenges that keep Electrical Vehicles from being adopted more widely. Some of these barriers are higher costs of ownership, performance, and the longevity of some of the components, like power electronics and electric motors.
The composite material works with any component that has copper. This includes bus bars, Electric vehicle traction inverters, and charging systems.
ORNL researchers deposited carbon nanotubes on the surface of flat copper substrate to create a composite material that handles current better and whose mechanical properties beat copper. This material is lighter than copper and performs better.
Carbon nanotubes (CNTs) being used to make a copper matrix better is nothing new. CNTs lightweight, strength, and conductivity have made them a favorite material for such attempts before. But previous experiments have created in materials with shorter material strength and poor scalability, or poor performance when longer.
The team at ORNL opted to deposit CNTs using the electro spinning method which is commercially viable and hence more scalable to create fibers using a jet of liquid speeding through an electric field.
With this technique, you enjoy a higher ability to control the orientation and structure of the deposited material, according to ORNL post doctoral researcher Kai Li who is based in the Chemical Sciences Division.
Scientists were this time able to orient the CNTs in one direction for improved electrical flow.
The team of scientists used a technique of vacuum coating called magnetron sputtering during which they add thin copper films on top of copper tapes coated with CNT. The copper samples yielded a super conductive Cu-CNT network when they were annealed inside a vacuum furnace.
They executed this by creating a solid and uniform layer of copper and allowed copper to be diffused into the CNT matrix.
ORNL scientists created a copper-carbon nanotube composite using this technique. The composite measured 10 centimeters in length and 4 cm in width and exhibited excellent material properties.
The material has microstructural properties and was analyzed at the ORNL Center for Nanophase Materials which is a user facility with the US Department of Energy Office of Sciences. The researchers established that the composite had a current capacity that was 14% greater and mechanical properties 20% greater than pure copper.