New approach for electric vehicle composite battery housings: Electromagnetic shielding and flame retardancy of PUR/UP-based sheet moulding compound

In a battery electric vehicle, the battery housing fulfils safety functions such as electromagnetic shielding and flame retardancy. Composites like sheet moulding compounds (SMCs) offer significant potential in the pro duction of battery housings. However, to achieve both electromagnetic shielding and flame retardancy in one material,conventional SMCs must be modified. This study examined the electromagnetic shielding and flame retardancy of unsaturated polyester polyurethane hybrid (UPPH) resin-based SMCs containing either glass- or carbon-fibre reinforcement as well as carbon black, carbon nanotubes, carbon nanostructures or expandable
graphite filler. The electromagnetic shielding was tested using test plates and test housings. The flame retardancy was investigated by limiting oxygen index (LOI) tests, UL94 tests, cone calorimeter tests and bench-scale fuel fire tests. The best results in terms of electromagnetic shielding and flame retardancy were achieved by using UPPH composites with 50 wt-% carbon fibres and 11.5 wt-% expandable graphite.