Multifunctional FRP-aluminum foam setup for battery housings of electric vehicles

Abstract

The battery systems of electrified vehicles are characterised by increasing weight due to larger battery modules. A lightweight battery carrier structure can reduce the system weight by replacing heavy metallic housing components by materials like fibre-reinforced plastics (FRP) and aluminum. The battery housing has to meet several requirements, e.g. stiffness, crash and intrusion protection, proof of leakage and thermal management. Present battery housings are manufactured using pressure die-cast aluminum in combination with steel carrier structures and are cooled actively. A novel approach is a lightweight hybrid battery housing consisting of a thermoformed FRP as stiff outer shell and an integrated closed cell aluminum foam infiltrated with phase-change-material for passive thermal management. This multi-material setup enables substitution of functionally separated systems in one intelligent solution. In the Open Hybrid LabFactory an entire process chain was built up including the aluminum foaming process, the thermoforming of FRP with heating and consolidating as well as the integrated forming and joining process of FRP with aluminum foam. With the goal of application-orientated research, a battery housing of an existing electric car was used to define requirements such as design space and mechanical specifications. Based on parameter studies an optimised process setup was achieved, which will be described in this paper