BMW says it will cut more than 600 lb from the weight of its
first electric vehicle through extensive use of carbon-fiber-reinforced
plastics (CFRP).
Engineers at BMW Group are
developing the Megacity architecture from scratch and will use CFRP for body
panels and some interior parts. It represents the most extensive use ever of
carbon composites in cars. The new electric vehicle is due in 2013.
A key factor is a back-integrated approach to producing
carbon composites that will improve their cost structure by a factor of more
than 50 percent.
SGL Automotive Carbon Fibers, a joint venture of the BMW
Group and SGL Group, is building a plant in Moses Lake, WA, to produce carbon
fiber. The plant will operate two lines, each with annual capacity of 1,500
metric tons. The first line is expected to be commissioned late next year.
"The decision to build the carbon fiber plant in Moses Lake
was based primarily on the availability of renewable clean hydropower and
competitive energy costs in the state of Washington," says Joerg Pohlman,
managing director, SGL Automotive Carbon Fibers. "Favorable infrastructure
conditions, existing utilities, a skilled labor force and fast permitting
processes were also important contributing decision factors."
The plant will produce industrial-grade carbon fiber, which
costs less than half ($10 versus $25 per pound) the grade used in high-end race
cars. SGL will also make use of industrial scrap, a concept under close
analysis at nearby Boeing, which uses CFRP in the
Dreamliner
787.
The plant's output initially will go to the Megacity, which
will be assembled in Leipzig, Germany. The four-seat hatchback will use aluminum
for chassis components. A lithium-ion battery with about 35 kWh of capacity will
be located below the vehicle's floor and is expected to offer about 100 miles
of range.
BMW is not a stranger to CFRP. It molds its own roofs with
the material for the M3, a racing car that recently competed in the Petit Le
Mans.
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