When the BMW i3 city car rolls out of your company’s Leipzig plant later this year, it can represent the first carbon-fiber car that can be produced in any quantity-about 40,000 vehicles per year at full output. The lightweight but sturdy nonmetallic structure in the new commuter car, the effect of BMW’s joint venture with SGL Technologies in Wiesbaden, will mark a milestone in the development of carbon-fiber-reinforced plastic (CFRP) materials, which may have traditionally been very costly for use in automotive mass production.
CFRPs are engineered materials which are fabricated by embedding webs of carbon fiber inside molded polymer resins. The fibers bolster the physical properties of the plastic matrix component in a similar manner 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 from the production process during the next three to five years should cut CC composite costs enough to complement those of aluminum chassis, which still command reduced over standard steel car frames.
CFRP structures weigh half that relating to steel counterparts along with a third below aluminum ones. Add the inherent corrosion resistance of composites along with the ability of purpose-designed, molded components to slice parts counts by a factor of 10, along with the interest automakers is clear. But despite the advantages of using CFRPs, composites cost far more than metals, even allowing for their lighter in weight. The top prices have to date limited their use to high-performance vehicles including jet fighters, spacecraft, racecars, racing yachts, exotic sports cars, and notably, the newest Airbus and Boeing airliners.
Whereas steel goes for 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 and also the reinforcing fiber costs yet another $2 to $30/kg, depending on quality. To allow cars to clear the Usa government’s fast-approaching 54.5-mpg average fuel-economy bar, automakers and their suppliers are striving to create methods to produce affordable carbon-fiber cars around the mass-scale.
But adapting structural composites to low-cost mass production is definitely a technical and manufacturing challenge, said Ross Kozarsky, Senior Analyst at Lux Research, an impartial research and consulting firm that is focused on emerging technologies.
Kozarsky follows composite materials and led a report team that just last year assessed CFRP manufacturing costs and identified potential innovations in each step of your complex process.
“Our methodology would be to follow, through visits and interviews, the full 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 designed 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 people segments when it comes to sales is ending, Kozarsky said. The wind-turbine business will deal with aerospace for your top market as larger, more-efficient offshore wind-power installations are built.
“It’s cheaper to make use of bigger turbine blades, that may simply be made using carbon-fiber materials,” he noted.
The Lux report predicted the 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 major cost-driver. During the same period, demand for carbon fiber is predicted to increase 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 more than twelve smaller Chinese companies.
“A lot of individuals are talking about automotive uses now, which can be totally at the opposite end in the spectrum from aerospace applications, since it has a much higher volume and many more cost-sensitivity,” Kozarsky said. After a slow start, the car industry will delight in another-largest average industry segment improvement through the entire decade, growing at a 17% clip, in accordance with the Lux forecast.
The Lux analysis suggests that CFRP technology remains expensive for the reason that of high material costs-in particular the carbon-fiber reinforcements-and also slow manufacturing throughput, he reported.
“The industry has reached an intriguing precipice,” he said, wherein industrial ingenuity will vie with the traditional technical challenges to try to satisfy the new demand while lowering costs and speeding production cycle times.
The most effective-performing carbon fibers-the larger grades found in defense and aerospace applications-start out as what is called PAN (polyacrylonitrile) precursors. Due to difficulty from the manufacturing process, PAN fibers cost about $21.5/kg, based on Kozarsky, who explained that makers subject the PAN to several thermal treatments where the material is polymerized and carbonized as it is stretched. The resulting “conversion” leaves the filaments oriented along the length of the fiber to give it the optimal strength and toughness. Various post-processing stages along with 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 is funded with $35 million in United states Department of Energy money as among the more promising efforts to lessen fiber costs. Part 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 master plan is to test various types of potential low-cost fiber precursors including the cheaper polymers, inexpensive textiles, some produced from low-quality plant fibers or renewable natural fibers for example wood lignin, and melt-span PAN.
Near term the Lux team expects the project that ORNL has been doing with Portuguese acrylic-fiber maker FISIP (majority belonging to SGL) on textile-grade PAN to attain costs at the pilot-line scale of $19.3/kg in 2013. Although significant, it might 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 said, is “at best 2 kg of PAN yields 1 kg of carbon fiber, which provides you with 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 could possibly be achieved by 2017, stated the report.
The Oak Ridge group, Kozarsky said, is additionally working on novel microwave-assisted plasma carbonization techniques that could produce useful, uniform fiber properties. And ORNL’s nonthermal plasma oxidation process is shown to have the potential to stabilize and cross-link the precursor materials rapidly and efficiently.
Polyolefin-precursor carbon fiber, along 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 lot of desire for boosting the resin matrix at the same time,” with research focusing on using thermoplastics as opposed to the existing thermosets and producing higher-toughness, faster-processing polymers.