Recently, scientists at the Oak Ridge National Laboratory (ORNL) in the United States have used new technology to create a composite material that can increase the current capacity of copper wires, thereby providing a scale that can be scaled for ultra-high efficiency , New materials for traction motors of electric vehicles with high power density.
This research aims to reduce the barriers that hinder the widespread adoption of electric vehicles, including reducing costs and improving the performance and life of components such as electric motors and power electronics. The material can be deployed in any component that uses copper, including more efficient busbars and smaller connectors for applications such as electric vehicle traction inverters and wireless and wired charging systems.
In order to produce conductive materials with lighter weight and better performance, ORNL researchers deposited and arranged carbon nanotubes on a flat copper substrate to form a metal matrix composite material whose current handling capacity and mechanical properties are better than those of a single The copper is better.
It is not a new idea to incorporate carbon nanotubes (CNT) into the copper matrix to improve electrical conductivity and mechanical properties. Carbon nanotubes are an excellent choice due to their light weight, high strength and electrical conductivity. But other researchers’ past attempts at composite materials have resulted in very short material lengths of only microns or millimeters, limited scalability, or poor performance of longer materials.
The ORNL team decided to try to deposit single-walled CNTs using electrospinning, which is a commercially viable method that generates fibers through an electric field through liquid velocity jets. Kai Li, a postdoctoral researcher in ORNL's Department of Chemical Sciences, explained that the technology can control the structure and orientation of deposited materials. In this case, the process allowed scientists to successfully orient the carbon nanotubes in a general direction to facilitate the flow of electric current.
Then, the team used magnetron sputtering to add a thin copper film on top of the CNT copper-plated copper tape, and then annealed the coated sample in a vacuum furnace to produce a dense and uniform copper layer. Conductive Cu-CNT network and allow copper to diffuse into the CNT matrix.
Using this method, ORNL scientists have created a copper-carbon nanotube composite material with a length of 10 cm and a width of 4 cm with excellent properties. Furthermore, the microstructure characteristics of the material were analyzed by using the instrument of the Nanophase Materials Science Center of the Office of Science and Technology of the United States Department of Energy. The researchers found that compared with pure copper, the current capacity of the composite material increased by 14%, and the mechanical properties increased by 20%.
Tolga Aytug, the lead researcher of the project, said: "By embedding all the outstanding properties of carbon nanotubes into the copper matrix, our goal is to increase mechanical strength, reduce weight and increase current capacity. Then, we will achieve a lower power consumption. , Better performance conductors, which in turn improves the efficiency and performance of equipment. For example, improved performance means that we can reduce the size and increase the power density of advanced motor systems."
This work builds on ORNL's long history of superconductivity research, which has produced excellent materials that conduct electricity with low resistance. The laboratory’s superconducting wire technology has been licensed by many industry suppliers to achieve high-capacity power transmission while minimizing power loss.
The ORNL team is also studying the use of double-walled CNT and other deposition techniques to produce samples with a length of about 1 meter. Burak Ozpineci, head of ORNL’s electric drive technology program and head of the Power Electronics and Motors Division, pointed out: “Electric motors are basically a mixture of metals, including steel laminates and copper windings. To achieve the 2025 electric For automotive goals, we need to increase the power density of electric drives and reduce the size of electric motors by 8 times, which means that material performance must be improved."