Composites
Reinventing cars with CFRPs The automotive industry, an epitome of technology revolution, is going back to milling practical and functional vehicles. Composites and other lightweight materials are expected to play integral roles in the design and manufacture of this next generation of vehicles, says Angelica Buan in this report.
Less weight driving Carbon fibre has already enjoyed a good following, particularly among car makers who are shifting to using carbon fibre composites in major parts. For instance, German luxury automotive maker BMW and carbon fibre maker SGL Group will triple production of carbon fibre at the US plant to 9,000 tonnes/year, as BMW prepares to expand the use of CFRPs in its electric i and M series. BMW’s i3, the first fully electric vehicle, features a 22-kWh lithium-ion battery pack, and a passenger cell and other parts constructed of CFRPs.
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n average car normally weighs between 3,000-4,000 kg. But times are changing and metals are being replaced by carbon fibrereinforced polymers (CFRPs) to produce more robust yet lighter vehicles. Comparably, CFRPs are stiffer by unit weight than glass fibre and metals, and 50% lighter than conventional steel as well as 30% lighter than aluminium. A CFRP study by the India-headquartered research firm Industry Experts revealed that global volume demand for CFRPs was estimated at around 67,000 tonnes in 2012 but by 2020, consumption will reach 210,000 tonnes, with a 15.3% CAGR. In terms of value, demand for CFRPs, estimated at US$10.25 billion in 2012, is expected to grow by 11.9% over 2012-2020 and reach US$25.2 billion by 2020.
The Audi Sport Quattro features a number of CFRP parts
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MAY 2014
BMW’s i3, the first fully electric vehicle, features a passenger cell and other parts constructed of CFRPs
BMW also plans to start production of its first plug-in hybrid two-plus-two sports car, the i8, that will feature a passenger cell and other parts made from CFRPs. Germany’s Audi debuted its plug-in hybrid vehicle last year and showed an improved model at this year’s Consumer Electronics Show in Las Vegas. The splitter is made of CFRP as is the diffuser. Rounding up the grille package is the CFRP facing and flared sills. Canada-headquartered automotive parts supplier Magna Exteriors is supplying CFRP painted automotive body panels for two 2016 model vehicles. Magna utilises Zoltek’s Panex 35 carbon fibre to develop CFS-Z carbon fibre sheet moulding compound. Meanwhile, the continuous fibre-reinforced Tepex composites from Germany-based Lanxess subsidiary Bond-Laminates are finding new applications in the area of automotive bodywork. One example is the use of a variant of Tepex dynalite to provide engine compartment protection in the MINI John Cooper Works GP. The protector is manufactured by compounding PP with continuous glass fibre rovings and forming the component directly from the resulting DLFT (Direct Long Fibre Thermoplastic) mass in a compression mould.
Composites
Compression moulding for CFRPs is increasing. Voestalpine Plastics Solutions succeeded in processing Lanxess's Tepex dynalite with a DLFT polyamide in a production mould for a PP-based GMT to produce a trunk recess for a sports vehicle from a German manufacturer
Harri Dittmar, Lightweight Design Expert at BondLaminates believes there is immense scope for using Tepex dynalite as underbody protection in cars – especially in vehicles destined for countries with poor roads that therefore require extra protection. “Sandwich DLFT solutions can be up to 50% lighter than steel and 20% lighter than aluminium protection. Thermoplastic sandwich composites also provide more effective sound insulation from stone hits – in other words they demonstrate superior acoustic properties too,” Dittmar adds. In view of the properties of carbon fibre, other leading car makers like General Motors, Toyota and Daimler are likewise developing models using the composites. Carbon fibre Alongside the increase in use for CFRPs in cars, suppliers are developing new products and speeding up processing techniques. In its 2013 review, Carbon Composites eV (CCeV), the German association of composite companies and research institutes, says that members of CCeV accounted for 40% of global fibre production in 2012. About 97% of carbon fibre used in composite materials is processed into CFRPs, according to the report. The increased consumption for carbon fibre has seen the concurrent increase of capacities. For instance, Japanese producer Toray Industries increased its carbon fibre capacity to 21,100 tonnes and acquired Zoltek this year, which also ramped up capacity to 17,600 tonnes/year in 2013. Others like Russia-based Argon (CJSC Holding Company Composite) and Alabuga Fibers, each has expanded capacity by 1,500 tonnes/year while South Korea’s Taekwang Industrial has expanded its capacity to 1,500 tonnes/year. In 2012, Dow Chemical and Turkish acrylic fibre maker Aksa Akrilik Kimya Sanayii set up DowAksa Advanced Composites to manufacture and commercialise carbon fibre. Last year, the joint venture partners tied up with nanotechnology company Rusnano and Russian carbon fibre maker Holding Company Composite (HCC) to launch production of carbon fibre intermediates, composite
materials, and solutions in Russia. DowAksa has 3,600 tonnes of capacity in Yalova near Istanbul. Still according to CCeV data, the largest installed carbon fibre capacities are found in the US, with Europe (including Turkey) and Japan, each accounting for some 23%-24% of global output. Meanwhile, China has expanded its production to around 11% of total global capacity (based on the 2013 review); Taiwan, South Korea, Russia, India and Mexico are also contributing significantly to the global output. In the automotive sector, Europe accounts for 56% of the global consumption, while North America and Japan take up 26% and 14%, respectively. Not going full blast yet The sky is the limit for the growth of carbon fibre and CFRP use in the automotive industry but it has not reached its full potential yet. There are indeed barriers that have to be addressed, says the American Chemistry Council (ACC). Firstly, the cost is a hindrance, followed by recycling and environmental pressures placed on automotive makers to ensure that the composite components are recyclable. The cost of raw carbon fibre can be between five to 25 times more than fibre glass; CFRPs cost even more compared to steel. There are also applications where conductivity is a requirement and carbon fibre needs to be used, against other materials. But hopes are high that CFRPs will benefit from advanced technologies to lower their costs, and thereby, widen their applications, especially for serial production of automotive vehicles. A research team at US-based Oak Ridge National Laboratory (ORNL) is developing new carbon fibre materials that cost lower. The US Department of Energy (DOE) awarded a US$35-million grant for the R&D venture as part of the agency’s Vehicle Technologies Programme that has ploughed an investment of around US$20 million. Industrial consortium members include 3M, BASF, Dow Chemical, Ford, GE, Graftech International, SGL, Toho Tenax America, United Technologies, and Volkswagen, as well as other government agencies. The pilot plant is capable of producing up to 25 tonnes/year. Initially, materials such as low-cost polymers, inexpensive textiles made from low-grade, low-quality plant fibres, and renewable natural fibres such as lignin, which is a by-product of paper mills, will be tried out. Various processes will also be employed to come up with modified or substitute versions of the precursor polyacrylonitrile (PAN). About 90% of the carbon fibres are made from PAN, which is expensive, thereby hiking up manufacturing costs. Similarly, in an effort to gain further adoption of CFRPs, the US automotive and polymer industries have also created a roadmap towards 2030, under the guidance of the ACC Plastics Division. With this, it will recognise plastics and polymer composites as preferred material solutions that meet, and in many cases set, automotive performance and sustainability requirements. MAY 2014
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