Bayer MaterialScience, a Bayer Group company, has asserted it sees good prospects for the increasing use of plastics in future mobility technologies, since compared with conventional materials they are held to save weight, increase efficiency and durability and improve appearance.
Estimates Hans-Peter Neuwald from the company’s automotive team: “The proportion of plastics in automotive applications should increase from 15% today to as much as 25% by 2020. It is not just the weight reduction driving this. It is much more the emerging economies playing catch-up in terms of quality, safety and comfort.”
The use of innovative driver assistance systems, cameras, sensors and products for the protection of pedestrians is also seen as another factor favouring the use of plastics.
Bayer believes the trend towards electric mobility, in particular, has given new impetus to automotive lightweight construction. It is argued that electric cars have to ‘slim down’ if they are to have sufficient range per charging cycle of the batteries, which continue to be heavy. Adds Claus Rüdiger, an expert for polycarbonate applications in electric mobility at Bayer MaterialScience: “We are therefore seeing increased demand for our plastics as alternatives to heavier materials such as steel and glass. This applies to both the production of bolt-on bodywork parts and to interior components, such as fascia and pillar trim.”
The use of Bayer’s polycarbonate Makrolon in automotive glazing is viewed as particularly attractive as it can reduce weight by as much as 50% compared with similar glass components. Furthermore, the integration of functions via the injection/injection compression moulding process reduces component costs. Bayer asserts that entire glazing modules, such as complete tailgates, can now be manufactured to weigh less using Makrolon and corresponding blended materials.
Current developments are also taking advantage of polycarbonate’s superior thermal insulation properties compared with glass to reduce the amount of energy needed to heat the cabin, again seen as being particularly beneficial with electric cars. They draw their heating energy from the battery, which reduces the vehicle’s range.
Polycarbonate also helps to reduce the weight of automotive headlights. One example given is “the LED lenses for the low-beams in the headlights of a German luxury sedan.” The lenses made of Makrolon LED 2245 weigh some 50% less than if they were made of glass.
Polycarbonate plastics are also viewed as being well suited for reducing the weight of batteries in electric vehicles when used as case materials, for example. “We are working on special grades of our Bayblend FR blends, which play an important role in concepts for flame-retardant, electrically insulating, yet lightweight batteries,” adds Rüdiger. One useful side effect is that compared with metal, the blends also provide for good thermal insulation of the batteries, ensuring that these continue to function reliably at low temperatures.
Another development focus of Bayer MaterialScience is flame-retardant polycarbonate blends that can be used for the injection moulding of dimensionally stable, low-distortion frames for the cells of lithium-ion batteries. These materials also are seen as having good prospects for use in other assemblies in the electric drive system, such as components for the battery management system and power electronics that are in contact with live parts.
Another attractive field of application for polycarbonate and its blends as well as for polyurethanes are charging stations for electric vehicles. Berit Krauter, who is in charge of this polycarbonate application commented: “We have developed a variety of materials for charging station housings, some of which have already proven effective in volume production.” In addition to high flame-retardance and electrical insulation, the housings are characterised primarily by good mechanical performance and high impact strength, which protects them against vandalism.
