In order to reduce energy and material consumption in the production of vehicles, the Fraunhofer Institute IWU and its partners are developing vehicle components that can be used over multiple vehicle life cycles. For this purpose, the project team has developed a cycle-compatible open-source construction kit that contains durable and reusable modules.
In the KOSEL project, the project team created the basic concept for a light e-utility vehicle with a gross vehicle weight of 3.5 tonnes, whose components are entirely modular. The three main modules, front end, battery box and rear end, are connected to each other via fixed interfaces, so that replacement is possible with very little effort. “With the cycle-compatible modular system, individual components or complete vehicle parts can be replaced,” explains Patryk Nossol, a researcher at Fraunhofer IWU in Zittau. “As a result, the majority of the vehicle experiences a longer usage phase. The costs for repairs decrease and a longer economic operation is made possible.” The e-vehicle platform is designed and prototyped for service lives of up to 30 years and mileages of up to one million kilometres.
The concept envisages the use of durable materials in the highly stressed areas intended for multiple reuse. Carbon fibre reinforced plastics (CFRP) are best suited for this purpose. Although these have a comparatively high carbon footprint in production, they compensate for this, according to the scientists, through their low mass and high fatigue strength over long periods of use if used correctly. “CFRP is the better alternative when these non-visible assemblies are used over more than one life cycle, as in the present concept,” says Nossol. Because of its long-term usability, carbon-fibre-reinforced plastic was primarily intended for use in the sill area. Here, the absorbers consisting of CFRP tubes are arranged at different angles to protect against different impact angles. The absorbers are fixed in pot-like receptacles, which are arranged in such a modular way that they can be easily replaced.
To ensure safety for the occupants, numerous crash scenarios are simulated, tested and analysed. From the data obtained, the scientists intend to derive suitable safety measures.
The circular KOSEL mobility concept is intended for fleet vehicles with a medium number of units. The prerequisite for this is the establishment of a circular value chain that can test individual components after the first life cycle and revise them if necessary. The concept is intended to serve as a model and trigger further similar developments in the mobility sector. Especially with an elaborated, circular e-vehicle platform as a standard solution, development costs and risks can be reduced. The open-source interfaces also make it attractive for suppliers to provide suitable standard components.
The KOSEL demonstrator will be presented at the Hannover Messe trade fair from 17 to 21 April 2023 at the Fraunhofer joint stand in Hall 16, Stand A12.