It could be out with copper and in with aluminium if BMW has its way.
Scientists from the Technische Universitat Munchen (TUM) are teaming with engineers from BMW in an effort to replace copper with aluminium as a conductor in on-board power systems.
Copper is heavy and expensive when compared to aluminium and with electric power becoming increasingly important, a switch to a cheaper option is preferred.
If aluminium is to be used however, then a number of technological issues must be addressed. For example, when temperatures are high aluminium often displays a distinct creep behaviour and conventional conductors could not be used as they would become loose over time. Even using aluminium based elements in cables and copper-based elements in connection areas would also cause issues because of the high electrochemical potential between a copper contact and an aluminium cable.
To counter these difficulties the aluminium based LEIKO concept was invented. It includes a sheet metal cage that enhances the mechanical stability of the plug and means there will be long-term support of the contact pressure spring. In addition, the researchers have come up with a special wedge-based geometry for the aluminium contacts so the aluminium creep now leads to the two contacts snuggling closer and closer over time to only enhance the electrical connection.
The addition of on-board cables arises because aluminium has a lower electrical conductivity. However, this may be addressed because aluminium is very pliable and the standard values for copper cable processing could still be applied.
Now researchers are looking into the ageing process in an effort to determine the suitability of the concept by 2012 – initial results indicate that material substitution will boost weight, cost and emissions.
