To meet the Department of Energy’s 2025 targets for electric vehicles, EV manufacturers must improve powertrains and increase power density of the electric drive. A new composite from Oak Ridge National Laboratory (ORNL) puts the targets in reach. The superconducting material uses a combination of copper and carbon nanotubes to improve overall energy efficiency, as well as boost the performance of powertrains and their components.
The composite increases the electrical current capacity of copper wires: by up to 20% compared with pure copper, according to ORNL researchers. The conductors improve energy utilization through reduced ohmic losses, minimized transport power, and lighter wires and cables. Oak Ridge’s achievement also enables better thermal management across system components like powertrains.
The material, which measures 10 centimeters long and 4 centimeters wide, can be deployed not just in powertrains, but in any component that uses copper, including bus bars and small connectors for electric vehicle traction inverters. The conductors, in fact, potentially benefit all energy sectors, ranging from on- and off-board components in electric vehicles (EV), interconnects to electronic devices, and motors.
These kinds of advanced materials and conductors significantly improve the efficiency of all on- and off-board electrical conduction applications for electric vehicles – components like converters, batteries, wiring, interconnects, busbars, and charging systems.
The Tech Briefs Q&A with Oak Ridge lead researcher Tolga Aytug reviews how the team created the carbon nanotube-and-copper composite.
- What are the barriers to electric-vehicle adoption that your composite material is designed to address and overcome?
- What inspired your carbon-nanotube design?
- How complex and challenging is the process to create the created a copper-carbon nanotube?
- What does this kind of composite provide for electric vehicles, and how do you envision this kind of material supporting a future of electric vehicles and better components like powertrains?
The interview reveals the ORNL manufacturing process: how the researchers deposited and aligned carbon nanotubes on flat copper substrates, resulting in a metal-matrix composite material; how the single-wall carbon nanotubes (CNTs) were deposited using a controlled process called electrospinning; and how the fibers were oriented in one general direction to facilitate enhanced flow of electricity.
“The production of these material utilizes scalable and commercially viable processing methods, but the process is not as simple as melting copper and mixing CNTs together,” Aytug told Tech Briefs.
Aytug explains how he and his colleagues used a vacuum coating technique called magnetron sputtering to add thin layers of copper film on top of the nanotube-coated copper tapes. The coated samples were then annealed in a vacuum furnace to produce a highly conductive copper-carbon network. A dense, uniform copper layer allowed diffusion of copper into the CNT matrix.
Check out the Tech Briefs Q&A, as the ORNL lead investigator Tolga Aytug explains how the improved power (and improved powertrains) could potentially boost adoption of electric vehicles.Read: New Composite Energizes the Electric Vehicle Market