Text Size AAA Bookmark and Share

BMW’s Big Bet on Carbon Fiber

By Wendee Nicole

 

With the new i3, the world meets the first composite-intensive mainstream EV.

On the streets of Barcelona, green car expert Jim Motavalli finally got to take the new BMW i3 for a ride.

Author of High Voltage: The Fast Track to Plug In the Auto Industry, Motavalli was attending the annual EVS-27 International Electric Vehicle Symposium & Exhibition, where enthusiasts test drove the highly anticipated electric car. The i3 didn’t disappoint. “It’s very quick off the line, very quiet, very good handling,” says Motavalli. As you’d expect from the engineers at the ‘fun to drive’ European automaker, he continues, the i3 is undoubtedly “a performance car.”

BMW has completely reinvented the way to manufacture a car with the i3, crafting the world’s first production car—not just electric vehicle (EV)—with an all-carbon-fiber passenger compartment. Six times stronger than commonly used steel and 30 percent lighter than increasingly popular aluminum, carbon fiber has historically been too expensive for bulk use, yet it holds great promise for making gasoline-powered autos radically more fuel efficient and opening the door for their cost-effective electrification, getting cars off oil completely.

But delivering on carbon fiber’s sustainability promise—crucial to delivering on the BMW i series’ promise of carbon-emissions-free transportation—required making not just the material work, but also the energy and financials.

Doing that ultimately led BMW to establish a carbon-fiber production facility in Moses Lake, Washington, where the automaker could use 100 percent renewable, climate-friendly hydropower for one-fifth the European price. (The i3 completes its production at two facilities in Germany—Landshut and Leipzig.)

THE PATH TO THE COMPOSITE-INTENSIVE CAR

The road to Moses Lake began earlier, with BMW’s strong climate-motivated commitment to sustainability, prodded by increasingly stringent European and American fleet fuel economy regulations. “As an overall fleet of models worldwide, we want to reduce CO2 emissions dramatically,” says Oliver Walter, Head of BMW i3 Products and Launch Management Worldwide. “[That] will not be possible with only V8 and 6-cylinder engines.”

There was also the issue of growing consumer demand for EVs, which BMW watched carefully before boldly merging into the market with the i3. “We don’t want to wait until everybody bypasses us,” Walter explains. “We want to be the driving force behind it.” After BMW tested e-mobility with two electric vehicles built on traditional car platforms—the MiniE, followed by the ActiveE—the German automaker was ready for full-scale production of an electric car.

The i3 is the result of that effort. “We call [the i3] the battery electric vehicle 2.0 because it’s not a conversion anymore; it’s 100 percent designed for electromobility,” says Walter, noting that many other recently released EVs, such as the popular Nissan LEAF, were built on the guts of a gas-powered counterpart; not so for the i3, which was designed and built from the ground up with electric drive in mind. “With [our other cars] it’s an evolution direction, whereas with the i brand we go into the revolutionary direction,” he says.

FROM CONCEPT TO REALITY

“We chose carbon fiber because for us it’s the only lightweight material you can use in the automotive industry without any concessions to safety,” says Manuel Sattig, BMW i series Project Manager. That said, it takes the right set of benefits—strength and safety gains, weight savings and efficiency improvements—for pricey carbon fiber to pay off. And so traditionally, smaller amounts of the material have been incorporated into parts on low-volume premium cars, like the Lamborghini, Porsche Spyder, and Chevrolet Corvette.

The i3, on the other hand, was carbon fiber for the masses. “When looking at carbon fiber, we had to take two separate actions: bring down the cost of the material and bring down the production cycle times for the material,” Sattig explains. Harkening to the days when Ford manufactured its own steel for the Model T, BMW decided to produce carbon fiber itself—unusual in today’s auto industry—in a joint venture with SGL Carbon SE.

“We set up a production chain going from the sourcing of the precursor material to the production of the carbon fiber itself and then the production of fabrics,” says Sattig. At Moses Lake, ultra-thin filaments go through a series of heating and cooling ovens, where they gradually turn into a molecular chain link of carbon crystals, weighing half what they did at the start. These filaments are sprayed with epoxy and shipped to Germany where they get woven into flexible mats. Eventually, robots mold these fabrics into the pieces needed for the i3—130 in all, compared to around 400 for a steel-bodied car. Having a carbon-fiber passenger cell also eliminates the need for many bolts and screws, further reducing the car’s weight. While bolts are needed elsewhere in the vehicle’s body, “the whole car underwent a specific weight diet,” says Sattig. “We looked at every screw, every bolt, every piece.”

BMW calls this carbon-fiber skeleton the Life module. Meanwhile, an aluminum Drive module—the electric powertrain, plus crash-critical and other components—is built in parallel, and the two halves of the i3 come together at the end in Leipzig. This parallel process enables the speedy production BMW needs for the quasi-mainstream i3. In fact, BMW cut its self-reported production times on the i3 in half compared to its non-carbon-fiber, gas-powered 3 series.

That said, BMW has been tight-lipped about its actual annual production volume the i3 is initially ramping up to. Industry media have estimated  30,000 units per year, with the option of rapid expansion if demand warrants. That’s a common mid-volume level, but short of the 50,000-or-more units necessary to truly reach high-volume production. The world’s best-selling models are made at the biggest factories in hundreds of thousands per year.

PROOF IN THE PERFORMANCE

Not only is carbon fiber new to the car, but the whole idea of a completely new architecture, a new production concept, a completely new drivetrain,” says Sattig. “It’s been a lot of hard work.” That hard work has paid off in an exciting new vehicle.

Superficially, the i3 has four seats and a usable trunk space of around 200 liters, plus extra cargo space if the rear seats are folded down. But what’s really notable are the performance specs. Because of the i3’s carbon-fiber skeleton, the car weighs 600 to 1,200 pounds less than electric cars converted from a gas-powered vehicle frame, says Sattig, resulting in some peppy weight-loss-induced numbers. Compared to the Nissan LEAF, the i3’s most relevant point of comparison, the i3 boasts a significantly more powerful engine that does 0 to 60 mph several seconds faster plus a one-third-longer range … all with a smaller battery pack (no small matter, given currently high battery costs). That’s the power of designing an auto from the ground up around carbon fiber. We can likely expect even further gains as automotive designers ascend the learning curve for carbon-fiber-intensive vehicles.

“I got to throw it around,” Motavalli says of his test drive, taking corners and driving fast, like the typical European driver. “It feels very fast and very sporty. It was a lot of fun to drive.” RMI’s Amory Lovins, after a recent test drive in Munich, concurs. “It in no way compromises the sportiness at the heart of BMW’s brand,” he says. “Two decades ago, I felt BMW was one of two automakers worldwide most likely to combine the engineering and strategic qualities needed to leapfrog to carbon-fiber electric cars. I’m thrilled they’ve now done it, and eager to see how it evolves next.”

THE ROAD AHEAD

With the November 2013 European release of the i3 still fresh in everyone’s minds—not to mention its 2014 release in the U.S. and East Asia—it’s too soon to say where BMW will go with the i3 from here. But you can be sure there’s more carbon fiber in the automaker’s future, from the forthcoming i8 to some of its more traditional fueled models that will benefit from the i3’s lessons.

There’s also the bigger question of carbon fiber’s place in the automotive industry and BMW’s investment in the technology just may be the stamp of approval carbon fiber needs. “If such a huge company makes such a transformative change in the way it designs its vehicles, that testifies to how promising carbon fiber technology can be for the automotive industry,” says Greg Rucks, a manager for Rocky Mountain Institute’s transportation practice.

 

CATERING TO CUSTOMERS

It will take more than an automaker such as BMW investing in carbon fiber for the technology to become truly widespread in cars, however. There’s still the issue of customer demand and adoption, not just of EVs, but of carbon-fiber-intensive autos.

“As long as the vehicles are as safe and functional as today’s vehicles, most consumers won’t care what material their vehicle is made of,” says Rucks. “They will, however, notice the benefits of carbon fiber construction even if most are unaware of the material itself: greater fuel efficiency, quicker acceleration, and better safety ratings.”

Those benefits are great, and BMW is further making sure that customers’ transition from gas-powered autos to carbon-fiber-based electric vehicles like the i3 is as comfortable and seamless as possible, while alleviating common concerns such as range anxiety. For BMW, this is about more than making and selling cars. BMW i series customers get a shiny new performance car, yes, but they also get a holistic suite of mobility services. In tandem with the i3, BMW designed what it calls its 360 Electric Mobility Program. “Our focus is to break down those barriers to EV adoption so we can get the customers to understand that driving electric is an achievable means of transportation,” says Robert Healey, BMW North America’s EV Infrastructure Manager.

Connected vehicle technology estimates driving range, can shift into modes such as Eco Pro to conserve energy, and can help navigate to public charging stations, among other features. An i Remote smartphone app puts such data in the palm of drivers’ hands when they’re not behind the wheel. BMW offers gas-powered loaners for longer trips than the i3’s range. The automaker facilitates installation of a Bosch level 2 in-home charger (for homeowners) or connecting with EV-friendly garage owners (for urban residents without their own parking space). BMW likewise gets new i3 owners signed up for access to Chargepoint’s nationwide network of public charging stations, and offers a 10 percent discount with SolarCity for a residential solar PV installation for customers who want to charge their EV with rooftop renewable energy.

With a premier brand like BMW behind such a revolutionary vehicle, driving one can feel exhilarating. “We have tremendous admiration for what they’ve done,” says Rucks. “It’s a gratifying leap towards the types of vehicle we envision for the future of the transportation industry.” That future includes truly high-volume-production carbon-fiber-intensive autos. With the i3, it’s one step closer to reality.

Wendee Nicole is a freelance writer whose work has appeared in Scientific American and Nature.

Photos courtesy of BMW A.G.

---------------------------------------------------------------------------------------------------------------------------------------------------------------------------

AUTOCOMPOSITES COMMERCIALIZIATION LAUNCHPAD

The Autocomposites Commercialization Launchpad (ACL) was created by RMI and industry partner Munro & Associates to advance the design, production, testing, and implementation of lightweight carbon fiber composite parts on mainstream vehicles by model year 2018. Eight major U.S. supply-chain companies are already signed on. The ACL’s goal is to achieve high-speed production volume of at least 50,000 units per year, a target not yet achieved with carbon fiber composites in any industry anywhere in the world. By securing the first rope across the chasm between pilot-scale and commercial production, the ACL aims to enable a full-fledged bridge to the revolutionary ultralight vehicles at the heart of achieving an oil- and carbon-emissions-free transportation system by 2050.