With all the cameras, sensors and other devices designed for driver comfort and safety, today’s cars house more than 2000 electrical connectors. And these connectors need to provide uninterrupted electrical contact no matter how cold, wet or bumpy the ride. Materials scientist Frank M\u00fccklich, FASM, Professor of Functional Materials at Saarland University, Germany, has developed a laser surface texturing procedure that makes the surfaces of the electrical contacts more stable and more efficient. In recognition of this work, the professor has now been awarded the Albert Keil Prize by the German Association for Electrical, Electronic & Information Technologies for outstanding achievements in the field of electrical contacts.<\/p>\n
Most of the problems that arise in modern cars are caused by faults in the electrical system. But when a car’s electronic display system indicates a fault, it’s not usually due to a defect on a complicated circuit board, but to a faulty electrical connection, where electrical contact has been broken (sometimes for only a fraction of a second) as a result of a change in temperature or humidity or mechanical vibration.<\/p>\n
\u201cThe process that we have developed enables us to drastically reduce the electrical contact resistance by up to 80 percent compared with electrical contacts between conventionally engineered surfaces. Given that there are more than 2000 plug-in connectors in a medium-sized car, our procedure yields a significant increase in the vehicle’s overall functional reliability. This means that electrical signals are transmitted far more reliably even in adverse weather conditions such as high humidity or extreme heat or cold,\u201d said M\u00fccklich.<\/p>\n
The technique the team developed is direct laser interference patterning (DLIP) and produces biomimetic, microstructured surfaces. The DLIP method uses interference patterns that are created when several laser beams spatially overlap to produce microscopically fine, symmetrical patterns on a material surface. The result is a periodic microscopic structuring of the surface at the micrometer scale, where the height of the structures created is less than the thickness of a human hair. Another key aspect of the DLIP method is that it is industrially efficient achieving speeds of up to one square meter per minute.<\/p>\n
\u201cPlug connections fabricated from such precisely microstructured surfaces function more reliably, even after they have been manually opened and closed multiple times during the regular servicing that all cars are subjected to,\u201d explained M\u00fccklich.<\/p>\n
The researchers drew inspiration from the natural world, where surfaces with this kind of microtopographic structuring is known to exhibit special effects. Well-known examples include the lotus plant with its water-repellent leaves or the wing of a butterfly, whose shimmering iridescent colors are not due to the presence of pigments but to light interference effects.<\/p>\n
\u201cWe’ve been developing this new technique in close collaboration with our partners over many years and it’s now a marketable technology that can be deployed efficiently in the rapid processes of industrial mass production,\u201d said M\u00fccklich.<\/p>\n
The Albert Keil Prize was awarded to Professor M\u00fccklich not just for his work on DLIP, but in recognition of a number of other technologies that can also be used to meet the challenges posed by the shift to electromobility.<\/p>\n
Using a variety of 3D analytical techniques, Frank M\u00fccklich and his team can quantify the changes in the internal structure of a material caused, for instance, by the high current densities that arise when electrical contacts are switched.<\/p>\n
\u201cWe can see how the microstructure of a material changes on the micro-, nano- and atomic scale under mechanical or electrical loading. Due to the high battery capacities and fast charging speeds of modern electric vehicles (EVs), the electrical contacts and the charging infrastructure are subjected to significant electrical stresses. We can now understand quantitatively what is happening in the interior of the material during such processes, including gaining insight into how the electrical resistance of the material changes. This will facilitate the development of electrical components that are more robust and durable,\u201d he explained.<\/p>\n
This work is significant given the ongoing transition to more sustainable forms of energy and the strong growth in the share of EVs in the automotive market, but is perhaps of even more crucial importance for the reliability and operational safety of autonomous vehicles.<\/p>\n
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