Composites in the automotive industry
The technology of composite materials
Composite materials are formed by combining two or more materials that have quite different properties. The different materials work together to give the composite unique properties, but within the composite you can easily tell the different materials apart – they do not dissolve or blend into each other.
Composites have been made from a form of carbon called graphene combined with the metal copper, producing a material 500 times stronger than copper on its own. Similarly, a composite of graphene and nickel has a strength greater than 180 times of nickel.
As for fibreglass, it’s made from plastic that has been reinforced by filaments or fibres of glass. These filaments can either be bundled together, and woven into a mat, or they are sometimes cut up into short lengths which are randomly oriented in the plastic matrix.
With fossil fuels accounting for more than 80% of the world’s energy consumption, transport being 92% dependent on oil and global reserves diminishing over the time, world demand is constantly increasing due to the emergence of developing countries. Furthermore, with vehicles contributing to almost a third of global emissions, the emergency of developing more sustainable cars has become a priority. Global organizations and governments’ commitments follow the EU push for zero emissions by 2050, and on its side the European Union proposed its 2050 target to achieve net zero emissions. As a result, the European Union have been focusing on switching from gasoline-powered vehicles to electric vehicles (EVs) and hydrogen-powered vehicles to decrease world’s greenhouse gas emissions. To manufacture those vehicles, automakers use composite materials to encapsulate battery modules or enclosures inside high-strength carbon-fiber composites, glass fiber composites or glass fiber-reinforced thermoplastic or epoxy SMC among others. As global demand for EVs and hydrogen fuelled vehicles is increasing, composite technologies are growing to meet carmakers needs for battery manufacturing. Moreover, as conventional EV batteries are heavy and weight more than 400 kilograms with a metallic part that accounts for 100 kilograms to 160 kilograms, the need to use lighter materials is real.
Using composites materials offer significant benefits compared to metals: they help to reduce mass, corrosion issues, provide a greater design freedom with higher space efficiency, faster assembly, better flame resistance and durability, and still meet stiffness performance. Major industry leaders such as BMW are using composite materials to reduce weight in their battery modules thanks to carbon fiber composites that improve structural design for lightweight solutions. A great example of reducing mass of battery packs is the British company TRB Lightweight Structures that achieved a reduction of battery modules from 80 kilograms to 10 kilograms. Eric Pierrejean, JEC Group CEO, emphasized: “The automotive sector is accelerating the shift to electric and hybrid mobility, but also integrating alternative energy sources, like hydrogen. In both cases, composites materials have a significant role to play thanks to their benefits. They enable not only light weighting and a great design freedom, but also the integration of new functions, including connectivity, the housing & insulation of batteries in Electric Vehicles, the fuel storage for Hydrogen- or CNG- powered Vehicles…”
Composites increase steadily on mid- and high-volume production models market with glass fiber-reinforced polymers among others in applications such as body panels and frames, injection molded thermoplastics for bumper frames, lift gates and seat structures, and are also used in motorsports and luxury car market with especially carbon fiber materials. On the high-end car market, European automakers such as Mercedes and Porsche are adding an ecological dimension to their must-have criteria of design, speed and power. For instance, Mercedes-AMG GTA race cars are now equipped with high-performance natural flax fibers to provide sustainable bodywork solutions for bumpers. The new bumper offers an 90% reduction of total material emissions compared to the previous one made of carbon fiber as well as an 85% reduction of carbon dioxide emissions, considering all the manufacturing process from raw materials to final product. Another European carmaker that strives to improve its vehicle efficiency and sustainability is Porsche. For its 718 Cayman GT4 CS model, Porsche has worked on replacing interior carbon fiber parts with more sustainable composites to reduce carbon emissions and vibrations. The natural fiber composites offer a 90% reduction in total emissions as well as a 94% reduction in material emissions compared to the previous carbon fiber interior. Specialist Interior GT-Road Cars at Porsche Motorsport, Eduard Ene, declared: “We must all ensure that natural fiber composites are used more and more in the world of automotive components.” Moreover, one of the major players in the composite industry, Porcher Industries, has launched a new range of flax fiber-based thermoplastic composites for automotive industry. These flax fibers are used as composite stiffeners and are entirely made in France from growth to weaving. They can be thermocompressed, injection molded, and are recyclable and sustainable as an answer to the increasing needs from automakers for composite materials that are durable, eco-friendly, effective and attractive. This new environmentally conscious range is mostly designed for car door interiors, dashboards and other decorative elements. The different properties of thickness, flax dying, weave type, etc. enable to associate various inputs and offer many possibilities.
Ultimately, composites have become increasingly popular in the automotive industry to make a significant contribution to meeting automakers’ weight reduction and sustainability goals as they are playing a major role in ensuring a better vehicle efficiency through light weighting, and provide lighter solutions, thermal resistance and higher stiffness properties that make them a promising alternative to metal for battery materials.