Multi-Functional Battery Housing for Electric Vehicles

© Fraunhofer IWU | Rico Schmerler
Development chain in the "FunTrog" project.
© Fraunhofer IWU | Rico Schmerler
Manufacturing process chain for the battery housing subshell.

In the project "FunTrog" the Fraunhofer Project Center develops together with the TU Braunschweig a multi-functional battery housing. The approach for the function integrated electric vehicle component is a multi-material mix through the combination of fiber reinforced composites, aluminum foam and aluminum. The focus here is on the integration of the mechanical functions of the thermal management as well as crash and intrusion protection.

Only the integration of several functions into innovative material systems, makes increasing efficiency, safety, installation space and comfort requirements possible for series production.

The developed battery case is positioned in the vehicle bottom to realize a low center of gravity. It contributes to the stiffening of the structure in this area.

Its multi-functional lower housing shell is mainly built in sandwich construction, consisting of a metal cover sheet, an aluminium foam core and an organic sheet. For the floor layer made of fiber-reinforced thermoplastic, the use of natural fibers is investigated with regard to damping properties and sustainability.

The metal cover sheet, which is metallically bonded to the aluminium foam, is used to connect the battery modules with special inserts and to dissipate heat into the foam. The infiltration of the closed-cell aluminium foam with phase change material (PCM) is particularly innovative. In addition to the functions of intrusion protection and energy absorption in the event of a crash, the aluminium foam core can also be used for smoothing thermal load peaks and buffering excess heat.

Main focuses of the project:

  • Development of a new type of a functionally integrated battery housing
  • Production of aluminium foam semi-finished products and biobased FRP composites according to requirements
  • Joining technology: connection of the battery modules to the multi-material sandwich structure, joining of top and lower shell
  • Functional integration: integration of the mechanical functions of the thermal management as well as crash and intrusion protection
  • Economical process chain: Efficient process control, reduction of production steps
  • Manufacturing of a demonstrator

Project results:

  • Mass reduction of 29 % without thermal management
  • Mass reduction of 12 % including PCM
  • Reduction of process steps through integral forming and joining process

The project was funded by the state of Lower Saxony (funding number VWZN2990).