Housings for battery packs of electrical driven vehicles must be light, should have a high stiffness and should exhibit good energy absorption behavior. This can be accomplished by using innovative sandwich materials made of a combination of carbon fibre reinforced plastics (CFRP) and aluminium face sheets and a core layer of aluminium hybrid foam.
Aluminium-epoxy hybrid foams can be obtained by first producing small aluminium foam granules. The foamed granules are then coated with an epoxy adhesive which contains a foaming agent. After filling a hollow structure with the coated aluminium foam spheres the foaming and curing of the adhesive coating is initiated by a mild heat treatment at temperatures between 100 and 200°C. As a result a composite material is formed which consists of aluminium foam spheres embedded in a matrix of epoxy foam (hybrid foam). By placing and curing the coated granules between two face sheets hybrid foam sandwiches can be produced. Sandwich structures have not necessarily to be flat, the technology allows also the production of sandwich-like structures with bent face sheets and closed side surfaces. Insertion of fastening elements can also be done easily.
Relevant material properties of the hybrid foam like compressive strength and the overall achievements in this case study will be presented.