Once the BMW i3 city car rolls from the company’s Leipzig plant later this current year, it would represent the very first carbon-fiber car that can 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 effect of BMW’s joint venture with SGL Technologies in Wiesbaden, will mark a milestone in the growth of carbon-fiber-reinforced plastic (CFRP) materials, that contain traditionally been very costly to 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 your plastic matrix component in the same manner which 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 within the production process throughout the next 3 to 5 years should cut CC composite costs enough to complement the ones from aluminum chassis, which still command reasonably limited 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 as well as the ability of purpose-designed, molded components to reduce parts counts by way of a factor of 10, along with the entice automakers is obvious. But despite the key benefits of using CFRPs, composites cost significantly more than metals, even permitting their lighter in 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 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 the reinforcing fiber costs yet another $2 to $30/kg, according to quality. To permit cars to get rid of the U.S. government’s fast-approaching 54.5-mpg average fuel-economy bar, automakers in addition to their suppliers are striving to generate 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 unbiased research and consulting firm that focuses on emerging technologies.
Kozarsky follows composite materials and led a study team that a year ago 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 from your tow, yarn, and grade level onwards, examining the supplier structure and also 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 with regards to sales is ending, Kozarsky said. The wind-turbine business will cope with aerospace for your top market as larger, more-efficient offshore wind-power installations are built.
“It’s cheaper to use bigger turbine blades, which could just be made using carbon-fiber materials,” he noted.
The Lux report predicted how the global niche 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. In the same period, need for carbon fiber is expected to rise 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 a dozen smaller Chinese companies.
“A lot of individuals are speaking about automotive uses now, which is totally with the opposite end in the spectrum from aerospace applications, since it features a much higher volume and much more cost-sensitivity,” Kozarsky said. After having a slow start, the car industry will enjoy the second-largest average industry segment improvement throughout the decade, growing in a 17% clip, in line with the Lux forecast.
The Lux analysis shows that CFRP technology remains expensive primarily because of high material costs-in particular the carbon-fiber reinforcements-in addition to slow manufacturing throughput, he reported.
“The industry has reached a fascinating precipice,” he said, wherein industrial ingenuity will vie using the traditional technical challenges to try to 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 what exactly is called PAN (polyacrylonitrile) precursors. Due to difficulty of your manufacturing process, PAN fibers cost about $21.5/kg, according to Kozarsky, who explained that makers subject the PAN to some thermal treatments wherein the material is polymerized and carbonized as it is stretched. The resulting “conversion” leaves the filaments oriented along the duration 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 with the new Carbon Fiber Technology Facility at Oak Ridge National Laboratory (ORNL), which has been funded with $35 million in Usa Department of Energy money as one of the more promising efforts to reduce fiber costs. Section of the project is always to identify cheaper precursor materials that could be processed into good-quality fibers (see “Oak Ridge collaborates for cheaper carbon fiber,”. The master plan is usually to test many types of potential low-cost fiber precursors including 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 work that ORNL is performing with Portuguese acrylic-fiber maker FISIP (majority properties of SGL) on textile-grade PAN to obtain costs on the pilot-line scale of $19.3/kg in 2013. Although significant, it might be simply a modest reduction as compared to the 50% required for penetration in high-volume auto applications.
One of the main limitations of PAN, he explained, is the fact that “at best 2 kg of PAN yields 1 kg of carbon fiber, which provides you with a conversion efficiency of just 50%.” Dow Chemical is investigating dexnpky63 polyolefins-polyethylene, polypropylene-because the feedstock simply 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 might be achieved by 2017, stated the report.
The Oak Ridge group, Kozarsky said, can also be concentrating on novel microwave-assisted plasma carbonization techniques that may 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 most of these alternative thermal-treatment mechanisms, should reduce costs to sub $11/kg at pilot-line scale in 2017, he noted. Kozarsky added that “there’s lots of curiosity about improving the resin matrix also,” with research concentrating on using thermoplastics instead of the existing thermosets and producing higher-toughness, faster-processing polymers.