Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Aluminum to replace copper as a conductor in on-board power systems

08.02.2011
TUM-BMW collaboration clears obstacles to lighter, cheaper alternative

Electric power and electronics are playing an ever-increasing role in all kinds of vehicles. Currently copper is the conductive material of choice. But in comparison to aluminum copper is heavy and expensive. In particular for fully electric vehicles the switch to the cheaper and lighter aluminum would be an interesting option.

That is why the optimization of intricate power supply networks is now in the focus of engineering research. Scientists from the Technische Universitaet Muenchen (TUM), in collaboration with BMW engineers, have now found out what tricks make it possible to replace copper with aluminum.

At first glance it is not at all clear why copper is still used as conductor in modern electric or semi-electric vehicles – when aluminum is lighter and significantly less costly. However, before aluminum can replace copper in power supply systems, a number of technological challenges need to be surmounted. When temperatures are high – and there are many places in a car where that is the case – aluminum displays a distinct creep behavior. Conventional connectors could thus not be used, as they would become loose with time.

One possible alternative – the use of aluminum-based elements in cables and copper-based elements in connection areas – also entails problems. Because there is a high electrochemical potential between a copper contact and an aluminum cable, this kind of wiring would be very prone to corrosion. Besides, joining copper to aluminum is rather demanding with the current state of technology. In order to counteract the aforementioned difficulties, scientists of the chairs for High Voltage Technology and Power Transmission and for Metal Casting and Forming, in cooperation with the respective departments of the BMW Group, developed an innovative aluminum-based electrical connection concept in the project LEIKO.

A sheet metal cage, which is an electromagnetic compatibility requirement anyway, enhances the mechanical stability of the plug and guarantees the long-term support of the contact pressure spring. Because the necessary contact force is no longer provided by the contact elements themselves, the originally problematic creep behavior of aluminum turns into a contact stabilizing, and thus, positive property. This, in turn, also guarantees a constant contact force over a lifetime of ten years.

To this end the researchers came up with a special wedge-shaped geometry for the aluminum contacts. The aluminum creep now leads to the two contacts snuggling closer and closer together over time, thereby rendering the electrical connection better yet. Moreover, the consistent use of aluminum alloys and the ingenious application of precious metal plating made it possible to relocate the formation of corrosion-prone local elements to less critical locations in the system.

A further problem with substituting aluminum for copper is its lower electrical conductivity. In the case of high-power on-board systems in particular, the cable cross-sections, which are about 60 per cent larger, need to be taken into account in the construction of cable ducts and feed-throughs. One positive thing the scientists discovered was that because aluminum is very pliable, the standard values from copper cable processing, where bending radii are set based on the diameter, could also be used for aluminum.

In order to determine the long-term behavior of the coated aluminum contacts under even the rough conditions typical for motorized vehicles, the project partners, together with leading suppliers, have successfully initiated a further research project. Funded by the Bavarian Research Foundation (BFS), this project will deliver evidence on the aging behavior and thus the suitability of the concept by 2012.

Initial results indicate that the material substitution will lead to significant improvements in weight, cost, and ultimately emissions. "We expect the high-voltage on-board systems of most electric vehicles to be based on aluminum by 2020. Aluminum will find its way into low-voltage on-board systems as well, because the price of copper will rise significantly with increasing demand," says Professor Udo Lindemann from the Institute of Product Development at the TU Muenchen.

The project finds its theoretical counterpart in the Collaborative Research Center (SFB) 768, Managing Cycles in Innovation Processes, funded by the German Research Foundation (DFG). It aims to bundle competencies from computer science, engineering, economics, and the social sciences in order to look into challenges at the interfaces of innovation processes along with partners from industry. The goal of this research is to use an interdisciplinary perspective to develop industry-relevant solutions in dealing with dynamic changes in company environments, as well as in company internal process landscapes.

Another aspect of the research conducted within SFB 768 is a student project to develop an electrically driven go-cart. In order to experience the manifold challenges of innovation management first-hand, the students started with a standard base structure and went through the entire development process for all subsystems of the vehicle. The results of the LEIKO project are also integrated into the student project – the entire high-voltage on-board system is implemented in aluminum.

The results are to be incorporated in the TUM electro vehicle MUTE, which will be presented at the IAA 2011.

Publication: Langer, S.; Lindemann, U.: Managing Cycles in Development Processes - Analysis and Classification of External Context Factors, in 17th International Conference on Engineering Design, M. N. Bergendahl, M. Grimheden, and L. Leifer, Eds. Stanford University, California, USA: Design Society, 2009, pp. 1-539 - 1-550

Contact
Prof. Udo Lindemann
Chair of Product Development
Technische Universitaet Muenchen
Boltzmannstr. 15, 85748 Garching, Germany
Tel.: +49 89 289 15130, Fax: -15144
E-Mail: sekretariat@pe.mw.tum.de
Internet: http://www.pe.mw.tum.de
Technische Universitaet Muenchen (TUM) is one of Europe's leading universities. It has roughly 460 professors, 7,500 academic and non-academic staff (including those at the university hospital "Rechts der Isar"), and 26,000 students. It focuses on the engineering sciences, natural sciences, life sciences, medicine, and economic sciences. After winning numerous awards, it was selected as an "Elite University" in 2006 by the Science Council (Wissenschaftsrat) and the German Research Foundation (DFG). The university's global network includes an outpost in Singapore. TUM is dedicated to the ideal of a top-level research based entrepreneurial university. http://www.tum.de

Andreas Battenberg | EurekAlert!
Further information:
http://www.tum.de

More articles from Power and Electrical Engineering:

nachricht Team develops fast, cheap method to make supercapacitor electrodes
18.07.2017 | University of Washington

nachricht Magic off the cuff
11.07.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

Leipzig HTP-Forum discusses "hydrothermal processes" as a key technology for a biobased economy

12.07.2017 | Event News

 
Latest News

Researchers create new technique for manipulating polarization of terahertz radiation

20.07.2017 | Information Technology

High-tech sensing illuminates concrete stress testing

20.07.2017 | Materials Sciences

First direct observation and measurement of ultra-fast moving vortices in superconductors

20.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>