BMW looks to replace copper wire with aluminum in its EVs

BMW's novel aluminum connector tightens as the metal heats up and creep sets in. It could be used to implement an aluminum wiring system in EV to cut costs and weight.

Copper is the most frequently used metal in car wiring. And there are some good reasons for that. But the downsides are that its relatively expensive and weighs more than alternatives.

Both of those downsides are troublesome for the electric vehicles market. Not only are EVs already overly expensive, they also are range limited by their weight. Thus engineers at German luxury automaker BMW and researchers at Technische Universitaet Muenchen may be on to something exciting with a scheme they've cooked up to replace copper in car with aluminum.

Aluminum is already heavily used in electric vehicles' bodies for weight reasons. Tesla's Model S has a frame that's mostly aluminum with steel only being used to reinforce a handful of key areas.

The new BMW design revolves around novel spring-loaded aluminum cage connector. The cage holds the connector in place, resisting aluminum's tendency to creep when hot and come loose. The contacts themselves don't hold the connector in place but their wedge shape does cause them to wiggle together and tighten in place as the system operates.

A thin coating of rare earth metals and consistent use of aluminum alloys in the contacts would relocate corrosion to less critical areas, such as the cable face. A slight obstacle was the need for 60 percent thicker cables for high power electronics, given aluminum's poor conductance than copper. These problems were somewhat mitigated.

Professor Udo Lindemann a researcher at the Institute of Product Development at the TU Muenchen and one of the team members involved with the project firmly believes aluminum is the future for electric vehicles.

He said that 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.

He added that next up is an intense round of torture testing to make sure the electric connectors are truly hardy enough for in car lifespan. That test is currently in progress, funded by the Bavarian Research Foundation. It will wrap up in 2012.

（Sourced from www.dailytech.com）