When the BMW i3 city car rolls out of the company’s Leipzig plant later this coming year, it can represent the very first carbon-fiber car which will be manufactured in any quantity-about 40,000 vehicles a year at full output. The lightweight but sturdy nonmetallic structure of your 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, that have traditionally been very expensive to be used in automotive mass production.
CFRPs are engineered materials which can be fabricated by embedding webs of carbon fiber inside molded polymer resins. The fibers bolster the physical properties of the plastic matrix component in the same way which a 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 within the production process throughout the next three to five years should cut carbon composite costs enough to fit the ones from aluminum chassis, which still command limited over standard steel car frames.
CFRP structures weigh half those of steel counterparts and a third under aluminum ones. Add the inherent corrosion resistance of composites and the ability of purpose-designed, molded components to cut parts counts with a factor of 10, and the attract automakers is clear. But despite some great benefits of using CFRPs, composites cost far more than metals, even permitting their lighter in weight. Our prime prices have so far limited their use to high-performance vehicles for example jet fighters, spacecraft, racecars, racing yachts, exotic sports cars, and notably, the most up-to-date 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 as well as the reinforcing fiber costs one more $2 to $30/kg, dependant upon quality. To allow cars to get rid of the Usa government’s fast-approaching 54.5-mpg average fuel-economy bar, automakers in addition to their suppliers are striving to make ways to produce affordable carbon-fiber cars around the mass-scale.
But adapting structural composites to low-cost mass production has long been a technical and manufacturing challenge, said Ross Kozarsky, Senior Analyst at Lux Research, an independent research and consulting firm that is focused on emerging technologies.
Kozarsky follows composite materials and led a report team that a year ago 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 in 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.
Even though the sporting goods, military, and aerospace industries have traditionally developed and first applied composite materials, the pre-eminence of those segments with regards to 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 utilize bigger turbine blades, that may basically be made using carbon-fiber materials,” he noted.
The Lux report predicted the global marketplace for CFRPs will greater than double from $14.6 billion in 2012 to $36 billion in 2020, as innovative new production technologies lower carbon-fiber costs-the main cost-driver. During the same period, interest in carbon fiber is predicted to increase fourfold from 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 over twelve smaller Chinese companies.
“A lots of individuals are talking about automotive uses now, which can be totally at the other end in the spectrum from aerospace applications, since it has a greater volume and much more cost-sensitivity,” Kozarsky said. Following a slow start, the car industry will enjoy another-largest average industry segment improvement during the entire decade, growing at the 17% clip, in line with the Lux forecast.
The Lux analysis shows that CFRP technology remains expensive primarily because of high material costs-specially the carbon-fiber reinforcements-and also slow manufacturing throughput, he reported.
“The industry has reached an interesting precipice,” he stated, wherein industrial ingenuity will vie using the traditional technical challenges to attempt to meet the new demand while lowering costs and speeding production cycle times.
The ideal-performing carbon fibers-the bigger grades utilized in defense and aerospace applications-start off as what is called PAN (polyacrylonitrile) precursors. Because of the difficulty of your manufacturing process, PAN fibers cost about $21.5/kg, based on Kozarsky, who explained that makers subject the PAN to several thermal treatments in which the material is polymerized and carbonized because 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 and also the surface-acting additives help ensure durability and “handleability.
Kozarsky singled out a commercial/government R&D collaboration with the new Carbon Fiber Technology Facility at Oak Ridge National Laboratory (ORNL), which is funded with $35 million in Usa Department of Energy money as among the more promising efforts to decrease fiber costs. Portion of the project is to identify cheaper precursor materials which can be processed into good-quality fibers (see “Oak Ridge collaborates for cheaper carbon fiber,”. The program is to test various kinds of potential low-cost fiber precursors such as the cheaper polymers, inexpensive textiles, some produced from low-quality plant fibers or renewable natural fibers including wood lignin, and melt-span PAN.
Near term the Lux team expects the job that ORNL is performing with Portuguese acrylic-fiber maker FISIP (majority belonging to SGL) on textile-grade PAN to attain costs on the pilot-line scale of $19.3/kg in 2013. Although significant, it could be merely a modest reduction as compared to the 50% needed for penetration in high-volume auto applications.
One of the leading 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 just 50%.” Dow Chemical is investigating dexnpky63 polyolefins-polyethylene, polypropylene-because the feedstock mainly because 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, can also be focusing on novel microwave-assisted plasma carbonization techniques that could 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 sorts 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 plenty of fascination with improving the resin matrix also,” with research concentrating on using thermoplastics rather than the existing thermosets and producing higher-toughness, faster-processing polymers.