BMW i3 pioneers use of carbon fiber in mass-produced cars
BERLIN (Bloomberg) -- BMW's bid to transform the way it makes cars starts with hundreds of thousands of fine white strands snaking upwards in a production hall in rural Washington in the United States.
Looped through an almost mile-long course, what looks like the world's thinnest rice noodles will be stretched, toasted and eventually scorched black to create carbon fiber -- a material thinner than human hair and yet tougher than steel.
BMW will use the sleek, black filaments for the passenger frame of the i3 electric car, which goes on sale at dealers in Germany today and around the world in the coming months. It's the first effort to mass produce a car made largely from carbon fiber and represents the biggest shift in automobile production since at least the 1980s when the first all-aluminum car frames were made.
The strategy started taking shape six years ago, as Norbert Reithofer, then the newly appointed CEO, examined trends affecting the industry and concluded that increased environmental awareness would likely prompt tougher emissions regulations that could make the future of autobahn cruisers like the 5-series sedan unsustainable.
"Looking forward to 2020, we saw threats to our business model," Chief Financial Officer Friedrich Eichiner, who was head of strategic planning at the time, said in an interview in Munich. "We had to find a way to bring models like the 6 series, 7 series and X5 into the future."
For BMW to continue to sell cars that live up to the company's "ultimate driving machine" claim, the manufacturer needed to offset those emissions with a viable electric vehicle for growing cities, where more and more potential customers would live. That was the start of the i3.
At the time, electric cars had the reputation of being sluggish because of the heavy battery needed to hold a charge capable of moving the car at least 100 kilometers (62 miles) -- the range considered necessary for daily use. That meant the car needed to be lighter to reduce the size and cost of the power pack and improve handling. The lightest and strongest material available is carbon fiber.
The downside is that it's prohibitively expensive. Consultancy Frost & Sullivan estimates that carbon fiber costs about $20 (15 euros) per kilogram. That compares to about $1 (0.74 euros) for steel. BMW's goal is to get the expense of a carbon-fiber frame down to the level of aluminum by 2020.
While these thin, black filaments have been used for Formula 1 racers, elite sports cars like the Bugatti Veyron and Boeing Co.'s 787 jet, the material is untested in large-volume production because of the expense and because of the time and complexity involved. So BMW aimed to do what no one else had done: mass produce carbon fiber. At the time, BMW's initial plans amounted to about 10 percent of the global market for the material, leaving few alternatives to manufacturing its own supplies -- an unusual step in the modern-day auto industry, which has increasingly outsourced components to cut costs.
"BMW's approach recalls the days of the industrial revolution, when manufacturers started with raw iron ore or located factories near power sources," said Aravind Chander, an analyst with Frost & Sullivan in Chennai. "It's an aggressive approach and still unproven."
To produce the fiber, BMW formed a joint venture with SGL Carbon SE in 2009. Due to the strategic importance of the project, BMW even made the rare move to secure influence at the Wiesbaden, Germany-based manufacturer by buying a 16 percent stake, countering Volkswagen Group's purchase of a 10 percent holding. Susanne Klatten, a member of the Quandt family which controls BMW, also bought 27 percent of SGL, putting the company effectively out of reach of rivals.
Manufacturing with carbon fiber is far more complex than taking sheets of steel and pounding out body panels. It starts with stripping atoms from acrylic thread. The chains of carbon crystals are then stitched into mats, layered together and injected with plastic resin.
BMW's process involves at least three production sites and the fibers travel more than 5,000 miles before a finished car ultimately rolls off the line at a factory in the eastern German city of Leipzig.
While most carmakers are experimenting with carbon fiber, none are rushing to follow BMW. Daimler's Mercedes-Benz brand doesn't see carbon fiber as critical. Instead, it's engineering autos that can be powered by conventional engines as well as electric motors and plans by 2017 to roll out fuel cell cars, which have a longer range than battery-only vehicles.
"We think differently" about the benefits of building cars with carbon fiber, Daimler Chief Financial Officer Bodo Uebber said in an interview. "Let's see who has the better answer."
Audi, BMW's closest rival in luxury-car sales, looks to mix and match materials, including aluminum, lightweight steel as well as carbon fiber, rather than rely on one single solution, spokesman Josef Schlossmacher said.
The strategy to develop a carbon fiber-based electric car wasn't without its critics at BMW. Eichiner and CEO Reithofer had to defend their choices to skeptical company managers around the world to get the rank and file on board. "Some initially didn't see the need for electric vehicles and wanted us instead to build a super sports car," said Eichiner. "It wasn't as if the strategy was universally seen as a home run."
BMW and SGL pushed ahead with setting up a $100 million carbon-fiber factory, breaking ground on a site in Moses Lake, Washington, in July 2010. The town on central Washington's arid high plateau was selected after a global site search under the codename Chinook. Moses Lake, a three-hour drive from Seattle and an hour and a half from Spokane, is usually not much of a destination.
What ultimately tipped the scales for the town of about 20,000 was the nearby Columbia River. BMW wanted the car to use renewable energy from the start, and the local utility charges about 3 cents per kilowatt hour for hydro-power to run the plant's ovens and furnaces, less than one fifth the cost in Germany.
"BMW's decision to go all out and do carbon-bodied electric cars is brave," said Max Warburton, an analyst with Sanford C. Bernstein. "It's a reminder that they're more clued up, more focused and more long term than the competition."
Lighter than Leaf
The first fibers were made there in the summer of 2011 as a test run for eventual mass-market production. The i3 uses carbon fiber to protect the passengers and an aluminum under-body to hold the battery and absorb the force of an accident. Because carbon parts are reinforced plastic, they have some flexibility. But in the event of an accident, the plastic could rupture, which means the piece would need to be cut out and a new part bonded to it. In other words, it can't be bent back into shape.
Thanks to the material, the i3 weighs 20 percent less than Nissan Motor Co.'s Leaf, the world's best-selling electric car. That helps the vehicle accelerate to 100 kilometers per hour in 7.2 seconds, more than 4 seconds faster than the Leaf.
Detailed planning was certainly involved in the carbon-fiber transformation. It starts with an unimpressive acrylic thread, similar to that used for cheap sweaters. The fibers, which are custom made in Japan, are stretched along spools and then toasted at temperatures of more than 200 degrees Celsius (392 degrees Fahrenheit) for about an hour and a half, turning from gold to bronze to brown to black.
The non-carbon atoms are then scorched out of the fibers in furnaces at as much as 1,400 degrees Celsius. The environment inside the furnaces is oxygen free to keep the material from bursting into flame.
What results is a molecular chain link of carbon crystals. The glistening black strands -- each about one-seventh as wide as a human hair -- are separated into bundles of 50,000 fibers, which is more than standard in the industry. In the final processing area, the threads shoot across the room winding onto dozens of spools at once.
The factory is nearly autonomous. Less than a dozen people monitor the machines and occasionally open new boxes of acrylic thread to splice onto the next lot. The fiber production will go on, even if the i3 falls flat. Carbon components will start finding their way into BMW's mainstream lineup starting with the next 7 series.
"The investment in carbon fiber isn't about a single vehicle, but about future-proofing our entire portfolio and therefore our business," said Eichiner. "There's no way around making cars lighter, and steel is reaching its limit." In BMW's Leipzig factory, steel is no longer the measure of toughness. A sign there reads "nerves of carbon fiber."
The company's not afraid of going it alone. "When you take a new path, there's always risks involved," said Eichiner.
"But if we succeed here, then it's a huge chance, and the competition will need time to catch up. There are not many opportunities in this industry to gain an edge like that."Contact Automotive News