28 March/April 2024 | E-Mobility Engineering Lightweight with higher temperature resistance, thermoplastics are ideal for e-mobility powertrains, Nick Flaherty reports Plastic fantastic The push to make e-mobility designs lighter to boost range is driving significant innovation in materials. Thermoplastics are being redesigned to provide various combinations of temperature and flowability for manufacturing and plating capabilities. The latest thermoplastic material can even be used in the hostile environments of the electric motor, replacing aramid papers and enamel coatings of the wires used in rotors. This is reducing the cost of building motors while increasing power density and performance. Alternatively, thermoplastics can be used to create smaller, lighter motors in lower-cost designs, which can even result in 3D-printed vehicles. As voltages increase, thermoplastics are also being used more widely in charging systems, reducing their weight and cost. This is improving the durability and reliability of charging stations, which is a key challenge for the industry. The lighter materials also make it easier to ship and install charging stations, both for public use and at home. Thermoplastics are one of the two main types of plastic, the other being thermosets. When heat is applied, thermoplastic materials become soft and malleable, and become hard again once cooled, making them suitable for injection moulding. In general, the viscosity of thermoplastic melts is higher than for thermosets, but not necessarily for highly filled materials. This is key for e-mobility powertrain applications where the temperature issue is more important, particularly with highervoltage 800 V and 1000 V designs. However, there are limitations to using conventional thermosetting resins reinforced with carbon fibre (CFRP) because of the slow manufacturing speed, high price and low recyclability. As a result, thermoplastics such as polypropylene (PP) and polyethylene terephthalate (PET) have been used as a matrix, considering their cost-effectiveness, formability and recyclability. Among the thermoplastic polymers for the CFRP composite, PP is one of the most widely used thermoplastics in the industrial field, and it has the advantage of being particularly excellent in terms of shock absorption for e-mobility designs. Motor designs Thermoplastic materials are also being repurposed from internal combustion engines (ICE). One material was found to have very good insulation properties, especially on magnet wire; a characteristic that turns out to be key for Thermoplastics are being used in increasing areas in electric ground and air vehicles (Image courtesy of Modalt)
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