Once the BMW i3 city car rolls from the company’s Leipzig plant later this coming year, it will represent the first carbon-fiber car which will be made in any quantity-about 40,000 vehicles per year at full output. The lightweight but sturdy nonmetallic structure of the new commuter car, the result 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 have traditionally been too costly for usage 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 your plastic matrix component in a similar manner 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 3 to 5 years should cut CC composite costs enough to match those of aluminum chassis, which still command reasonably limited 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 along with the ability of purpose-designed, molded components to slice parts counts by way of a factor of 10, and the appeal to automakers is clear. But despite the benefits of using CFRPs, composites cost significantly more than metals, even permitting 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 most up-to-date 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 vary from $5 to $15/kg along with the reinforcing fiber costs one more $2 to $30/kg, depending on quality. To permit cars to remove the Usa government’s fast-approaching 54.5-mpg average fuel-economy bar, automakers as well as their suppliers are striving to make strategies to produce affordable carbon-fiber cars in 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 just last year assessed CFRP manufacturing costs and identified potential innovations in each step from the complex process.
“Our methodology is usually to follow, through visits and interviews, the whole value chain through the tow, yarn, and grade level onwards, examining the supplier structure along with the general market costs,” he explained. The Lux team then created a cost model that mixes material, capital expenditure, infrastructure, labor, and utility consideration and 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 people segments in terms of sales is ending, Kozarsky said. The wind-turbine business will contend with aerospace to the top market as larger, more-efficient offshore wind-power installations are constructed.
“It’s cheaper to make use of 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. In the same period, need for carbon fiber is expected to increase fourfold through 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 12 smaller Chinese companies.
“A large amount of people are talking about automotive uses now, that is totally on the opposite end from the spectrum from aerospace applications, since it comes with a higher volume and many more cost-sensitivity,” Kozarsky said. After having a slow start, the auto industry will like the second-largest average industry segment improvement throughout the decade, growing with a 17% clip, in line with the Lux forecast.
The Lux analysis shows that CFRP technology remains expensive due to the fact of high material costs-specially the carbon-fiber reinforcements-and also slow manufacturing throughput, he reported.
“The industry has reached an appealing precipice,” he stated, wherein industrial ingenuity will vie with the traditional technical challenges to attempt to match the new demand while lowering costs and speeding production cycle times.
The very best-performing carbon fibers-the bigger grades found in defense and aerospace applications-start off as precisely what is called PAN (polyacrylonitrile) precursors. Because of the difficulty of your manufacturing process, PAN fibers cost about $21.5/kg, as outlined by Kozarsky, who explained that makers subject the PAN to several thermal treatments where 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 an industrial/government R&D collaboration in the new Carbon Fiber Technology Facility at Oak Ridge National Laboratory (ORNL), which has been funded with $35 million in U.S. Department of Energy money as among the more promising efforts to decrease fiber costs. Section of the project is usually to identify cheaper precursor materials that could be processed into good-quality fibers (see “Oak Ridge collaborates for cheaper carbon fiber,”. The blueprint is usually to test various kinds of potential low-cost fiber precursors like the cheaper polymers, inexpensive textiles, some made from low-quality plant fibers or renewable natural fibers for example 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 properties of SGL) on textile-grade PAN to achieve costs at the pilot-line scale of $19.3/kg in 2013. Although significant, it might be only a modest reduction if compared to the 50% required for penetration in high-volume auto applications.
One of the main limitations of PAN, he explained, is “at best 2 kg of PAN yields 1 kg of carbon fiber, which supplies you with a conversion efficiency of just 50%.” Dow Chemical is investigating dexnpky63 polyolefins-polyethylene, polypropylene-because the feedstock since they could offer potential conversion efficiencies of 70% to 75%. If mechanical performance targets can 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 concentrating 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, put together with these types 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 increasing the resin matrix also,” with research concentrating on using thermoplastics instead of the existing thermosets and producing higher-toughness, faster-processing polymers.