If the BMW i3 city car rolls out from the company’s Leipzig plant later this season, it is going to represent the first carbon-fiber car that might be manufactured in any quantity-about 40,000 vehicles per year at full output. The lightweight but sturdy nonmetallic structure from the new commuter car, the result of BMW’s joint venture with SGL Technologies in Wiesbaden, will mark a milestone in the introduction of carbon-fiber-reinforced plastic (CFRP) materials, which may have traditionally been very expensive to be used in automotive mass production.
CFRPs are engineered materials that happen to be fabricated by embedding webs of carbon fiber inside molded polymer resins. The fibers bolster the physical properties of your plastic matrix component in a similar manner that the skeleton of steel rebar strengthens a poured-concrete structure.
Even though i3 electric vehicle (EV) won’t exactly come cheap-estimates run from $40,000 to $50,000-BMW reportedly claims that forthcoming improvements inside the production process during the next three to five years should cut carbon composite costs enough to suit those of aluminum chassis, which still command a premium over standard steel car frames.
CFRP structures weigh half that of steel counterparts along with a third lower than aluminum ones. Add the inherent corrosion resistance of composites and also the ability of purpose-designed, molded components to reduce parts counts by way of a factor of 10, as well as the appeal to automakers is clear. But despite the key benefits of using CFRPs, composites cost significantly more than metals, even making it possible for their lighter in weight. Our prime prices have thus far limited their use to high-performance vehicles such as jet fighters, spacecraft, racecars, racing yachts, exotic sports cars, and notably, the newest Airbus and Boeing airliners.
Whereas steel applies to between $.80 and $1/kg, and aluminum costs between $2.40 and $2.60/kg, polyester and epoxy resins range between $5 to $15/kg along with the reinforcing fiber costs an extra $2 to $30/kg, according to quality. To allow cars to get rid of the U.S. government’s fast-approaching 54.5-mpg average fuel-economy bar, automakers and their suppliers are striving to generate methods to produce affordable carbon-fiber cars on the mass-scale.
But adapting structural composites to low-cost mass production happens to be a technical and manufacturing challenge, said Ross Kozarsky, Senior Analyst at Lux Research, an unbiased research and consulting firm that focuses on emerging technologies.
Kozarsky follows composite materials and led research team that last year assessed CFRP manufacturing costs and identified potential innovations in each step of your complex process.
“Our methodology is usually to follow, through visits and interviews, the full value chain from the tow, yarn, and grade level onwards, examining the supplier structure along with the general market costs,” he explained. The Lux team then designed a cost model that combines material, capital expenditure, infrastructure, labor, and utility consideration and the chances for cost reductions.
Even though the sporting goods, military, and aerospace industries have traditionally developed and first applied composite materials, the pre-eminence of those segments regarding sales is ending, Kozarsky said. The wind-turbine business will cope with aerospace for the top market as larger, more-efficient offshore wind-power installations are designed.
“It’s cheaper to work with bigger turbine blades, which may only be made using carbon-fiber materials,” he noted.
The Lux report predicted that this global market for CFRPs will over double from $14.6 billion in 2012 to $36 billion in 2020, as innovative new production technologies lower carbon-fiber costs-the most important cost-driver. During the same period, need for carbon fiber is expected to rise fourfold from your current 27,000 million ton (24,500 million t) to 110,000 million ton (99,800 million t).
Major suppliers of carbon fiber include Toray, Zoltek, Toho, Mitsubishi, Hexcel, Formosa Plastics, SGL Carbon, Cytec, AKSA, Hyosung, SABIC, and over a dozen smaller Chinese companies.
“A lots of everyone is talking about automotive uses now, which can be totally on the other end in the spectrum from aerospace applications, since it possesses a greater volume and many more cost-sensitivity,” Kozarsky said. After a slow start, the car industry will like the next-largest average industry segment improvement during the entire decade, growing in a 17% clip, based on the Lux forecast.
The Lux analysis signifies that CFRP technology remains expensive for the reason that of high material costs-especially the carbon-fiber reinforcements-in addition to slow manufacturing throughput, he reported.
“The industry has reached an intriguing precipice,” he explained, wherein industrial ingenuity will vie with the traditional technical challenges in order to match the new demand while lowering costs and speeding production cycle times.
The very best-performing carbon fibers-the higher grades used in defense and aerospace applications-start out as what exactly is called PAN (polyacrylonitrile) precursors. Because of the difficulty of the manufacturing process, PAN fibers cost about $21.5/kg, in accordance with Kozarsky, who explained that makers subject the PAN to some thermal treatments when the material is polymerized and carbonized since it is stretched. The resulting “conversion” leaves the filaments oriented along the duration of the fiber allow it the perfect strength and toughness. Various post-processing stages and the surface-acting additives help ensure durability and “handleability.
Kozarsky singled out a commercial/government R&D collaboration in the new Carbon Fiber Technology Facility at Oak Ridge National Laboratory (ORNL), which was funded with $35 million in U.S. Department of Energy money among the more promising efforts to lower fiber costs. Area of the project is to identify cheaper precursor materials that could be processed into good-quality fibers (see “Oak Ridge collaborates for cheaper carbon fiber,”. The blueprint is always to test various types of potential low-cost fiber precursors like the cheaper polymers, inexpensive textiles, some made out of low-quality plant fibers or renewable natural fibers including wood lignin, and melt-span PAN.
Near term the Lux team expects the work that ORNL is performing with Portuguese acrylic-fiber maker FISIP (majority properties of SGL) on textile-grade PAN to accomplish costs on the pilot-line scale of $19.3/kg in 2013. Although significant, it would be merely a modest reduction as compared to the 50% necessary for penetration in high-volume auto applications.
One of the major limitations of PAN, he stated, is the fact “at best 2 kg of PAN yields 1 kg of carbon fiber, that gives you a conversion efficiency of only 50%.” Dow Chemical is investigating dexnpky63 polyolefins-polyethylene, polypropylene-since the feedstock since they could offer potential conversion efficiencies of 70% to 75%. If mechanical performance targets may be met, pilot-line costs of $13.8/kg might be achieved by 2017, stated the report.
The Oak Ridge group, Kozarsky said, is additionally taking care of novel microwave-assisted plasma carbonization techniques that will produce useful, uniform fiber properties. And ORNL’s nonthermal plasma oxidation process has been shown to have the potential to stabilize and cross-link the precursor materials rapidly and efficiently.
Polyolefin-precursor carbon fiber, coupled with these kinds of alternative thermal-treatment mechanisms, should reduce costs to sub $11/kg at pilot-line scale in 2017, he noted. Kozarsky added that “there’s a great deal of interest in enhancing the resin matrix also,” with research working on using thermoplastics as opposed to the existing thermosets and producing higher-toughness, faster-processing polymers.