When the BMW i3 city car rolls out from the company’s Leipzig plant later this current year, it would represent the 1st carbon-fiber car that can be created in any quantity-about 40,000 vehicles a year at full output. The lightweight but sturdy nonmetallic structure from the new commuter car, the consequence of BMW’s joint venture with SGL Technologies in Wiesbaden, will mark a milestone in the creation 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 that happen to be fabricated by embedding webs of carbon fiber inside molded polymer resins. The fibers bolster the physical properties in the plastic matrix component in the same way that a skeleton of steel rebar strengthens a poured-concrete structure.
Even though 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 throughout the next three to five years should cut carbon composite costs enough to fit those of aluminum chassis, which still command a premium over standard steel car frames.
CFRP structures weigh half that from steel counterparts as well as a third less than aluminum ones. Add the inherent corrosion resistance of composites along with the ability of purpose-designed, molded components to cut parts counts with a factor of 10, along with the interest automakers is clear. But despite the key benefits of using CFRPs, composites cost far more than metals, even enabling their lighter weight. Our prime 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 most recent 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 and also the reinforcing fiber costs one more $2 to $30/kg, dependant upon quality. Make it possible for cars to remove the U.S. government’s fast-approaching 54.5-mpg average fuel-economy bar, automakers in addition to their suppliers are striving to create approaches 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 unbiased research and consulting firm that focuses on emerging technologies.
Kozarsky follows composite materials and led a study team that just last year assessed CFRP manufacturing costs and identified potential innovations in each step of the complex process.
“Our methodology is to follow, through visits and interviews, the entire value chain in the tow, yarn, and grade level onwards, examining the supplier structure along with the general market costs,” he explained. The Lux team then developed a cost model that mixes material, capital expenditure, infrastructure, labor, and utility consideration and also 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 those segments when it comes to sales is ending, Kozarsky said. The wind-turbine business will cope with aerospace for that top market as larger, more-efficient offshore wind-power installations are designed.
“It’s less expensive to use bigger turbine blades, which could only be made using carbon-fiber materials,” he noted.
The Lux report predicted how the global marketplace for CFRPs will more than 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, need for carbon fiber is anticipated to increase 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 lot of individuals are speaking about automotive uses now, that is totally in the opposite end of the spectrum from aerospace applications, since it possesses a higher volume and more cost-sensitivity,” Kozarsky said. Right after a slow start, the auto industry will love the next-largest average industry segment improvement throughout the decade, growing at a 17% clip, in accordance with the Lux forecast.
The Lux analysis indicates that CFRP technology remains expensive primarily because of high material costs-specially the carbon-fiber reinforcements-as well as slow manufacturing throughput, he reported.
“The industry has reached an intriguing precipice,” he was quoted saying, wherein industrial ingenuity will vie with the traditional technical challenges in order to satisfy the new demand while lowering costs and speeding production cycle times.
The ideal-performing carbon fibers-the greater grades used in defense and aerospace applications-begin as exactly what is called PAN (polyacrylonitrile) precursors. Because of the difficulty in the manufacturing process, PAN fibers cost about $21.5/kg, based on Kozarsky, who explained that makers subject the PAN to a number of thermal treatments when the material is polymerized and carbonized as it is stretched. The resulting “conversion” leaves the filaments oriented along the size of the fiber allow 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 on 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 the more promising efforts to lessen fiber costs. Area 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 plan 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 like 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 accomplish costs on the pilot-line scale of $19.3/kg in 2013. Although significant, it will be merely a modest reduction when compared to the 50% needed for penetration in high-volume auto applications.
One of the major limitations of PAN, he was quoted saying, is that “at best 2 kg of PAN yields 1 kg of carbon fiber, which supplies you with a conversion efficiency of only 50%.” Dow Chemical is investigating dexnpky63 polyolefins-polyethylene, polypropylene-because the feedstock because they could offer potential conversion efficiencies of 70% to 75%. If mechanical performance targets can be met, pilot-line costs of $13.8/kg could be achieved by 2017, stated the report.
The Oak Ridge group, Kozarsky said, is likewise working 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, along 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 curiosity about enhancing the resin matrix also,” with research concentrating on using thermoplastics as opposed to the existing thermosets and producing higher-toughness, faster-processing polymers.