While the ever-improving battery technology is drawing a lot of attention in improving the range of electric vehicles, these machines have many moving parts that play a role in their overall performance. Scientists at the Fraunhofer Institute for Reliability and Microintegration have developed a new design that they believe works much more efficiently and could improve EV range by up to six percent.
An inverter is an electronic device that converts direct current to alternating current and, in the context of an electric vehicle, takes power from the battery and converts it to operate the electric motors. As an intermediary between the battery and the motor, the inverter and its transistors are designed for large electrical currents, which increases the temperature when the vehicle is used.
To counteract this, inverters in electric cars use fixed cooling elements with channels resting in the water, in which the heat is conducted and dissipated. These cooling elements are the focus of Fraunhofer scientists, who have developed advanced transistors for inverters made from silicon carbide semiconductors, which offer a lower rate of power loss when operating an electric vehicle.
The team set out to develop cooling elements for these advanced transistors that do not compromise on the performance gains of silicon carbide semiconductors. They used 3D printing to make cooling elements with much thinner walls and positioned the transistors on a thin metal plate just a few millimeters thick.
The result of this thinner design is that the transistors are closer to the cooling water, which enhances the cooling effects. The cooling channels also serve as structural components and support the metal plates. The thin nature of the materials allows them to absorb stress as the inverter heats and cools by deforming slightly. In addition, flexible copper wires bind the whole thing together instead of solid copper bars, which further reduces the load during operation.
"We expect that by optimizing the drive train in this way, the range of electric cars will ultimately be extended by up to six percent," says Eugen Erhardt.
Erhardt notes that there is still a long way to go to turn this prototype into a functional component of a production vehicle, although researchers will get a better idea of its potential in the coming months. This includes tests in cooperation with Robert Bosch and also with Porsche, who will install and test the inverter in a new, specially developed drive train.