Battery packs for electric vehicles (EVs) are very heavy due to the high number of battery cells required – which are typically encased in aluminium – and can account for 30 percent of the total mass in some vehicles. This not only increases the moving mass of the EV, but also keeps the cost of production high.
But now scientists at the Fraunhofer Institute for Structural Durability and System Reliability (LBF) have developed a lightweight battery pack that uses only fibre-plastic composites (FRP), which has made it possible to reduce the overall weight of the EV by 40 percent.
Dr Felix Weidmann, who is heading up the research project at LBF, sums up the problem which his team set out to resolve: "In order to increase the gravimetric energy density without having to change the cell technology, it is therefore obvious to make the necessary mechanical structures of the battery packs lighter," he says in a from LBF.
The FRP housings, which are based on a novel stress-adapted sandwich construction, are not only significantly lighter than aluminium and heat resistant but they can be manufactured economically. The production process combines foam injection moulding technology with thermoplastic FKV-Faser-Kunststoff-Verbund. This so-called “in-situ FKV-Faser-Kunststoff-Verbund sandwich process” enables the production of lightweight housings in just two minutes. Significantly, thermal insulation capability – which provides a high resistance to open flame and thermal energy input to meet EU industry requirements – can be achieved within the same process step, without the need for post-processing.
The project was funded by the European Commission under the H2020 support programme.