When the BMW i3 city car rolls from the company’s Leipzig plant later this coming year, it would represent the initial carbon-fiber car which will be manufactured in any quantity-about 40,000 vehicles per year at full output. The lightweight but sturdy nonmetallic structure in the new commuter car, the consequence 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 expensive to use 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 of your plastic matrix component in a similar manner a skeleton of steel rebar strengthens a poured-concrete structure.
Although the i3 electric vehicle (EV) won’t exactly come cheap-estimates run from $40,000 to $50,000-BMW reportedly claims that forthcoming improvements inside the production process throughout the next three to five years should cut CC composite costs enough to suit those of aluminum chassis, which still command limited over standard steel car frames.
CFRP structures weigh half those of 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 reduce parts counts by a factor of 10, along with the entice automakers is obvious. But despite some great benefits of using CFRPs, composites cost far more than metals, even enabling their lighter in weight. The high prices have to date limited their use to high-performance vehicles like 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 cover anything from $5 to $15/kg as well as the reinforcing fiber costs an additional $2 to $30/kg, dependant upon quality. Make it possible for cars to clear the Usa government’s fast-approaching 54.5-mpg average fuel-economy bar, automakers as well as their suppliers are striving to create ways to produce affordable carbon-fiber cars around 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 targets emerging technologies.
Kozarsky follows composite materials and led research team that last year assessed CFRP manufacturing costs and identified potential innovations in each step in the complex process.
“Our methodology is to follow, through visits and interviews, the entire value chain from your 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.
While the sporting goods, military, and aerospace industries have traditionally developed and first applied composite materials, the pre-eminence of those segments in terms of 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 constructed.
“It’s cheaper to make use of bigger turbine blades, which could basically be made using carbon-fiber materials,” he noted.
The Lux report predicted the global market 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 main cost-driver. Through the same period, need for carbon fiber is predicted to go up 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 large amount of everyone is talking about automotive uses now, which can be totally with the opposite end of your spectrum from aerospace applications, since it comes with a better volume and many more cost-sensitivity,” Kozarsky said. After having a slow start, the car industry will like another-largest average industry segment improvement through the entire decade, growing in a 17% clip, in accordance with the Lux forecast.
The Lux analysis suggests that CFRP technology remains expensive for the reason that of high material costs-in particular the carbon-fiber reinforcements-as well as slow manufacturing throughput, he reported.
“The industry has reached an intriguing precipice,” he explained, wherein industrial ingenuity will vie using the traditional technical challenges to try and fulfill the new demand while lowering costs and speeding production cycle times.
The ideal-performing carbon fibers-the greater grades employed in defense and aerospace applications-start off as what is called PAN (polyacrylonitrile) precursors. Due to the difficulty from the manufacturing process, PAN fibers cost about $21.5/kg, according to Kozarsky, who explained that makers subject the PAN to a series of thermal treatments where the material is polymerized and carbonized since it is stretched. The resulting “conversion” leaves the filaments oriented along the size of the fiber to give it the ideal strength and toughness. Various post-processing stages as well as the surface-acting additives help ensure durability and “handleability.
Kozarsky singled out a commercial/government R&D collaboration on the new Carbon Fiber Technology Facility at Oak Ridge National Laboratory (ORNL), which has been funded with $35 million in United states Department of Energy money as the more promising efforts to decrease fiber costs. Part of the project is always to identify cheaper precursor materials which can be processed into good-quality fibers (see “Oak Ridge collaborates for cheaper carbon fiber,”. The program is usually to test many types of potential low-cost fiber precursors such as the cheaper polymers, inexpensive textiles, some made from 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 owned by SGL) on textile-grade PAN to attain costs with the pilot-line scale of $19.3/kg in 2013. Although significant, it would be only a modest reduction in comparison to the 50% required for penetration in high-volume auto applications.
One of the major limitations of PAN, he stated, is the fact that “at best 2 kg of PAN yields 1 kg of carbon fiber, which gives that you simply conversion efficiency of only 50%.” Dow Chemical is investigating dexnpky63 polyolefins-polyethylene, polypropylene-since the feedstock since they could offer potential conversion efficiencies of 70% to 75%. If mechanical performance targets may be met, pilot-line costs of $13.8/kg may 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 can produce useful, uniform fiber properties. And ORNL’s nonthermal plasma oxidation process is shown to have the potential to stabilize and cross-link the precursor materials rapidly and efficiently.
Polyolefin-precursor carbon fiber, coupled with these kinds 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 lots of fascination with improving the resin matrix too,” with research concentrating on using thermoplastics instead of the existing thermosets and producing higher-toughness, faster-processing polymers.