35 E-Mobility Engineering | March/April 2024 Some suppliers of thermoplastic resins Belgium Syensqo +32 2 264 19 00 www.syensqo.com Germany BASF +49 62160 0 www.basf.com Covestro +49 5931 1560 www.covestro.com Lanxess +49 221 8885 0 www.lanxess.com Japan Toray +81 3 3245 5111 www.toray.com Saudi Arabia SABIC +966 11 225 8000 www.sabic.com The Netherlands Witcom Engineering Plastics +31 76 504 3080 www.wittenburggroup.com/ witcom USA Asahi Kaseo (USA office) +1 517 223 2000 www.akplastics.com Ascend Performance Materials +1 713 315 5700 www.ascendmaterials.com Celanese +1 972 443 4000 www.celanese.com Nexeo Plastics +1 833 303 0922 www.nexeoplastics.com LyondellBasell +1 713 309 7200 www.lyondellbasell.com coming generation of vehicles will rely heavily on 48 V systems. This is because a higher voltage is required to generate the power necessary to supply the processors that control highly automated systems. The 90 mm height means the pack can be stowed away in the trunk or under the passenger seat. The cells operate at up to 75 C, and so require a less complex cooling method and can use passive heat sinks. However, this needs a class of plastic with a higher temperature performance. The thermoplastic not only cuts costs and size compared with aluminium, but it can also be moulded into smooth, complex forms through injection moulding. The smooth surface finish helps with air flow throughout the platform, and it is simpler and more cost-effective to assemble than aluminium units. The use of plastics for battery pack casing is addressed in detail in EME 19 (May/June 2023), but several research projects are looking at how to achieve important properties such as electromagnetic shielding and fire resistance in thermoplastics. Reinforcing the material with long fibres enables the production of high-stiffness materials without compromising impact resistance. This is being used for a battery module that will be designed and validated in the laboratory through experimental electrical, mechanical and thermal tests, simulating various driving cycles. It is aimed at electric ground and air vehicles with high-temperature requirements. Thermoplastic composites with carbon fibres and PET have also been used for an underbody shield to protect the lithium-ion batteries from ground impacts. The underbody shield (UBS) is composed of two parts: the main shield plate and the collision protection bar (CPB). Mechanical behaviour against impact was assessed using finite element analysis, considering the position of the CPB and the shape of the underbody shield plate, and where an impact is likely to occur as a vehicle travels along a road. For the UBS, the hybrid composite of carbon fibre (CF)/PET and self-reinforced polypropylene (SRPP) were used, and the ratio between the CF/PET and SRPP was optimised. Through finite element analysis, the optimal underbody shield was designed with a thickness of 2.4 mm and a hybrid ratio of CF/PET:SRPP as 1:2. Finally, the UBS was manufactured using a thermo-forming process and mounted to an electric vehicle, and then a crash test was performed against a concrete obstacle. The developed underbody shield was able to successfully protect the battery against impact damage, showing the deformation of a rear part was within 5 mm and no battery leakage occurred. A world of opportunity The move from thermoset to thermoplastic materials is opening up new design opportunities across e-mobility with a huge range of materials. Selection is dependent on the exact requirements of the component, from tensile strength to temperature stability and coating capabilities. While thermoplastics can be reinforced with long and short carbon fibres to boost the tensile strength for applications such as battery packs and body protection panels, the materials are also being used in the powertrain of electric platforms. The ductility of the material means that certain thermoplastics can be used to replace the enamel around stator wires in a motor, improving power density and lowering overall weight, while also reducing the number of assembly steps. Thermoplastics are also being used for 3D printing in additive manufacturing. Prototype components can be developed quickly that have similar properties to the final design, which is particularly vital for light testing of electric aircraft. Acknowledgements With thanks to Simone Bottegal at Syensqo, Constantin Schwecke at Covestro and Fernando López at the Carlos III University of Madrid for their help in the preparation of this article.
RkJQdWJsaXNoZXIy MjI2Mzk4