Applications of aluminum hybrid foam sandwiches in battery housings for electric vehicles

Battery packs for purely electrical driven vehicles should allow for a long driving range, therefore they must be as light as possible. The aim of the project SmartBatt - funded by the EC under the 7th Framework Programme - was to create a 20 kWh battery pack which exhibits a 10-15% weight reduction as compared to the State of the Art. This was accomplished by using innovative sandwich materials made of aluminum face sheets and a core of aluminum hybrid foam for the battery housing. Aluminum-epoxy hybrid foams can be obtained by first producing small aluminum 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 aluminum foam spheres the foaming and curing of the adhesive coating is initiated by a mild heat treatment at temperatures between 100 and 200 degrees C. As a result a composite material is formed which consists of aluminum foam spheres embedded in a matrix of epoxy foam (hybrid foam). By placing and curing the coated granules between two face sheets aluminum hybrid foam sandwiches can be produced. The mechanical characteristics of the core layer material like compression strength and specific deformation energy absorption were determined using quasi-static and high strain rate compression tests. Relevant material properties and the overall achievements in this case study will be presented. (C) 2014 Published by Elsevier Ltd.