Aluminum busbar halves weight of battery power cabling

August 15, 2011 // By Christoph Hammerschmidt
Cable system provider Leoni AG offers a solid aluminium conductor for motor vehicle applications to wire the battery as an alternative to the common copper cable. It can be shaped in three dimensions and weighs only about half as much as the conventional component. Leoni will present this product for the first time at the IAA International Motor Show in Frankfurt, together with other lightweight construction solutions.

Of the roughly 3,000 meters of cable that today's motor vehicles contain, the connection between the battery and the engine is one of the bulkiest single cables. The potential for saving weight on this component is all the greater when the battery is located in the rear of the vehicle. Leoni has therefore replaced the copper battery cable with a round aluminium busbar, which can be fitted directly on or underneath the vehicle's chassis. It has a variable diameter depending on the application and is insulated with a halogen-free polyethylene jacket. Depending on the type of vehicle, it can have a length of more than four metres and be deployed in either a single or twin track version.

The aluminium busbar weighs only 40 to 60 percent as much as the common copper cable. The saving is made possible by the fact that aluminium has significantly less specific gravity than copper. In absolute terms, the weight saving can be up to three kilograms, which contributes to lowering CO2 emissions.

In addition, there is the distinctive characteristic that the increased diameter, which aluminium conductors would normally necessitate, can be avoided with larger cross sections. Its solid structure and a special manufacturing process considerably reduce the busbar's diameter. Compared with a multi-core copper cable with a 15.5 millimetre diameter, the aluminium busbar of identical conductivity has a diameter of less than 14 millimetres. The technology thus also helps to address the issue of diminishing installation space.

To ensure a perfect fit to the vehicle’s chassis, the busbar is designed CAD-controlled in a three-dimensional space. Its round shape makes continuous bending in all directions easily possible; something that other solutions available on the market do not permit. This facilitates inside bend radii that are no larger than the bar’s diameter.

Handling the rigid busbar is easier than is the case with a limp cable. The carmaker thereby saves time on installing in the