As soon as the BMW i3 city car rolls from the company’s Leipzig plant later this coming year, it can represent the very first carbon-fiber car that can be manufactured in any quantity-about 40,000 vehicles annually 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 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 which are fabricated by embedding webs of carbon fiber inside molded polymer resins. The fibers bolster the physical properties from the plastic matrix component likewise 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 from the production process during the next three to five years should cut CC composite costs enough to match the ones from aluminum chassis, which still command a premium over standard steel car frames.
CFRP structures weigh half that from steel counterparts plus a third lower than aluminum ones. Add the inherent corrosion resistance of composites and the ability of purpose-designed, molded components to reduce parts counts by a factor of 10, along with the appeal to automakers is apparent. But despite the advantages of using CFRPs, composites cost considerably more than metals, even enabling their lighter weight. Our prime prices have up to now 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 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 an extra $2 to $30/kg, depending on quality. Make it possible for cars to clear the U.S. government’s fast-approaching 54.5-mpg average fuel-economy bar, automakers in addition to their suppliers are striving to create ways to produce affordable carbon-fiber cars about 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 independent research and consulting firm that is focused on emerging technologies.
Kozarsky follows composite materials and led an investigation 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 entire value chain through the tow, yarn, and grade level onwards, examining the supplier structure as well as the general market costs,” he explained. The Lux team then designed a cost model that mixes material, capital expenditure, infrastructure, labor, and utility consideration along with the chances for cost reductions.
While 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 contend with aerospace for your top market as larger, more-efficient offshore wind-power installations are made.
“It’s more economical to make use of bigger turbine blades, which could just be made using carbon-fiber materials,” he noted.
The Lux report predicted that this global market 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 key cost-driver. In the same period, demand for carbon fiber is predicted to go up 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 over twelve smaller Chinese companies.
“A lots of individuals are referring to automotive uses now, which is totally in the opposite end in the spectrum from aerospace applications, since it features a better volume and much more cost-sensitivity,” Kozarsky said. Following a slow start, the auto industry will enjoy the next-largest average industry segment improvement through the 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-specially the carbon-fiber reinforcements-in addition to slow manufacturing throughput, he reported.
“The industry has reached an intriguing precipice,” he stated, wherein industrial ingenuity will vie together with the traditional technical challenges to try and fulfill the new demand while lowering costs and speeding production cycle times.
The most effective-performing carbon fibers-the greater grades found in defense and aerospace applications-begin as exactly what is called PAN (polyacrylonitrile) precursors. Due to the difficulty in the manufacturing process, PAN fibers cost about $21.5/kg, according to Kozarsky, who explained that makers subject the PAN to several thermal treatments in which the material is polymerized and carbonized as it is stretched. The resulting “conversion” leaves the filaments oriented along the length of the fiber allow it the ideal 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 was funded with $35 million in U.S. Department of Energy money as among the more promising efforts to lower fiber costs. Section of the project would be to identify cheaper precursor materials that could be processed into good-quality fibers (see “Oak Ridge collaborates for cheaper carbon fiber,”. The program is usually to test various types of potential low-cost fiber precursors such as 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 project that ORNL is performing with Portuguese acrylic-fiber maker FISIP (majority properties of SGL) on textile-grade PAN to attain costs on the pilot-line scale of $19.3/kg in 2013. Although significant, it will be simply a modest reduction in comparison to the 50% essential for penetration in high-volume auto applications.
One of the leading limitations of PAN, he stated, is “at best 2 kg of PAN yields 1 kg of carbon fiber, that gives a conversion efficiency of just 50%.” Dow Chemical is investigating dexnpky63 polyolefins-polyethylene, polypropylene-as the feedstock simply because they could offer potential conversion efficiencies of 70% to 75%. If mechanical performance targets might 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 focusing on novel microwave-assisted plasma carbonization techniques that can produce useful, uniform fiber properties. And ORNL’s nonthermal plasma oxidation process is shown to have the possibility to stabilize and cross-link the precursor materials rapidly and efficiently.
Polyolefin-precursor carbon fiber, combined 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 a lot of curiosity about improving the resin matrix too,” with research concentrating on using thermoplastics instead of the existing thermosets and producing higher-toughness, faster-processing polymers.