When the BMW i3 city car rolls out of your company’s Leipzig plant later this coming year, it is going to represent the first carbon-fiber car that will be created 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 costly to use 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 likewise that the skeleton of steel rebar strengthens a poured-concrete structure.
While the i3 electric vehicle (EV) won’t exactly come cheap-estimates run from $40,000 to $50,000-BMW reportedly claims that forthcoming improvements in the production process in the next three to five years should cut carbon composite costs enough to match those of aluminum chassis, which still command a premium over standard steel car frames.
CFRP structures weigh half that relating to steel counterparts plus a third less than aluminum ones. Add the inherent corrosion resistance of composites and the ability of purpose-designed, molded components to slice parts counts by a factor of 10, and the interest automakers is apparent. But despite the key benefits of using CFRPs, composites cost far more than metals, even enabling their lighter weight. The top prices have up to now limited their use to high-performance vehicles including jet fighters, spacecraft, racecars, racing yachts, exotic sports cars, and notably, the latest Airbus and Boeing airliners.
Whereas steel is true of between $.80 and $1/kg, and aluminum costs between $2.40 and $2.60/kg, polyester and epoxy resins cover anything from $5 to $15/kg along with the reinforcing fiber costs yet another $2 to $30/kg, dependant upon quality. Make it possible for cars to clear the Usa government’s fast-approaching 54.5-mpg average fuel-economy bar, automakers in addition to their suppliers are striving to come up with ways to produce affordable carbon-fiber cars about the mass-scale.
But adapting structural composites to low-cost mass production has always been a technical and manufacturing challenge, said Ross Kozarsky, Senior Analyst at Lux Research, an independent research and consulting firm that concentrates on emerging technologies.
Kozarsky follows composite materials and led an investigation team that this past year assessed CFRP manufacturing costs and identified potential innovations in each step from the complex process.
“Our methodology is always to follow, through visits and interviews, the whole value chain through the tow, yarn, and grade level onwards, examining the supplier structure and the general market costs,” he explained. The Lux team then developed a cost model that combines material, capital expenditure, infrastructure, labor, and utility consideration along with the chances for cost reductions.
Although the sporting goods, military, and aerospace industries have traditionally developed and first applied composite materials, the pre-eminence of the segments when it comes to sales is ending, Kozarsky said. The wind-turbine business will contend with aerospace for your top market as larger, more-efficient offshore wind-power installations are designed.
“It’s more economical to make use of bigger turbine blades, which may simply be made using carbon-fiber materials,” he noted.
The Lux report predicted that the global marketplace 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 major cost-driver. During the same period, requirement for carbon fiber is expected to rise fourfold in the 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 more than twelve smaller Chinese companies.
“A lots of everyone is discussing automotive uses now, that is totally in the opposite end in the spectrum from aerospace applications, since it features a better volume and many more cost-sensitivity,” Kozarsky said. Following a slow start, the car industry will delight in the 2nd-largest average industry segment improvement throughout the decade, growing in a 17% clip, in accordance with the Lux forecast.
The Lux analysis shows that CFRP technology remains expensive for the reason that of high material costs-in particular the carbon-fiber reinforcements-in addition to slow manufacturing throughput, he reported.
“The industry has reached an interesting precipice,” he said, wherein industrial ingenuity will vie with all the traditional technical challenges to attempt to meet the new demand while lowering costs and speeding production cycle times.
The most effective-performing carbon fibers-the greater grades used in defense and aerospace applications-start out as exactly what is called PAN (polyacrylonitrile) precursors. Due to difficulty of your manufacturing process, PAN fibers cost about $21.5/kg, as outlined by Kozarsky, who explained that makers subject the PAN to a number of thermal treatments in which the material is polymerized and carbonized because it is stretched. The resulting “conversion” leaves the filaments oriented along the size of the fiber allow it the perfect strength and toughness. Various post-processing stages and also the surface-acting additives help ensure durability and “handleability.
Kozarsky singled out an industrial/government R&D collaboration at the new Carbon Fiber Technology Facility at Oak Ridge National Laboratory (ORNL), that has been funded with $35 million in Usa Department of Energy money as one of the more promising efforts to lessen fiber costs. Area of the project would be to identify cheaper precursor materials that may be processed into good-quality fibers (see “Oak Ridge collaborates for cheaper carbon fiber,”. The blueprint is usually to test various types of potential low-cost fiber precursors such as the cheaper polymers, inexpensive textiles, some created from low-quality plant fibers or renewable natural fibers such as 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 belonging to SGL) on textile-grade PAN to achieve costs in the pilot-line scale of $19.3/kg in 2013. Although significant, it will be only a modest reduction in comparison to the 50% required for penetration in high-volume auto applications.
One of the leading limitations of PAN, he explained, is “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-as the feedstock because they could offer potential conversion efficiencies of 70% to 75%. If mechanical performance targets could be met, pilot-line costs of $13.8/kg might be achieved by 2017, stated the report.
The Oak Ridge group, Kozarsky said, is likewise concentrating on novel microwave-assisted plasma carbonization techniques that can 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, put together 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 curiosity about improving the resin matrix too,” with research focusing on using thermoplastics rather than the existing thermosets and producing higher-toughness, faster-processing polymers.