How can lightweight construction, functional integration, and thermal management be efficiently combined in electric vehicles? In the “InThElekt” project, the Fraunhofer Institute for Microstructure of Materials and Systems IMWS in Halle (Saale) has developed new solutions for this purpose in collaboration with partners: thermoplastic composite sandwich structures with integrable electronic components, data-driven quality assurance, and new material and heat dissipation concepts. The results demonstrate how components can be designed to be lighter, more feature-rich, and more suitable for manufacturing.
The approach of “InThElekt – Integral Thermoplastic Sandwich Structure Components with Adapted Electronics for Electric Vehicles” is to replace conventional metallic vehicle structures in electric cars with plastic components made using innovative composite sandwich technology and featuring integrated electronic components. This makes it possible to reduce vehicle weight, lower energy consumption, and increase range. A major challenge here is dissipating the heat generated by the electronic components, as plastic structures typically have low thermal conductivity. The consortium partners – ElringKlinger AG, EDAG Engineering GmbH, SimpaTec GmbH, Symate GmbH, NetCo Professional Services GmbH, Berliner Nanotest und Design GmbH, Fraunhofer IMWS, and Chemnitz University of Technology – have therefore developed solutions involving novel electronics encapsulation materials, thermal management, and interface concepts. Volkswagen AG, HÜBERS Verfahrenstechnik Maschinenbau GmbH, and ENGEL Austria GmbH participated as associated partners.
The focus of activities at Fraunhofer IMWS was on the development of lightweight composite sandwich structures with continuous-fiber-reinforced thermoplastic skins (organic sheets) and foamed cores produced using thermoplastic foam injection molding (TSG). These were combined with a process known as negative embossing to achieve the highest possible foaming ratios (TSG composite sandwich). This will enable the future production of lightweight components suitable for series production that meet structural and functional requirements for applications such as the automotive sector.
“In this project, we were able to demonstrate that lightweight construction, functional integration, and design optimized for manufacturability and material suitability can be effectively combined in thermoplastic sandwich structures. Using a lightweight assembly carrier as an example, we successfully demonstrated the innovative technology, electrical functional integration, and weight savings compared to the previous steel construction,” says Dr.-Ing. Matthias Zscheyge, who led the subproject “Research into novel thermoplastic sandwich technologies as well as innovative housing materials and heat dissipation concepts for the integration of automotive electronic components” at Fraunhofer IMWS.
One of the key challenges was to bring the complex interactions between material, process, and component geometry under control. The study examined in detail how different material systems, foaming processes, degrees of expansion, and process parameters – such as mold temperatures and holding times – affect the local foam structure and the associated mechanical properties of the sandwich composite. At the same time, suitable interfaces between structural and electronic components, as well as thermal management concepts, had to be developed.
In extensive campaigns, various test and demonstration structures were designed, implemented using tooling technology, and evaluated from a process engineering perspective. For example, a complex test mold for foam injection molding and the integration of organic sheet material, as well as an automation system using a robotic gripping system, were developed. Extensive experimental studies on physical and chemical foaming provided reliable data on foam structure, component quality, and reproducibility. For example, the rheological properties of the selected injection-molding compounds and the processing behavior of the thermoplastic tape face layers as a function of process parameters were comprehensively characterized, as were the resulting mechanical properties of the sandwich structures and boundary layers. Non-destructive testing methods such as X-ray computed tomography and ultrasound were also used to analyze porosity, cell distribution, cover layer structure, and local structural quality in detail. Mechanical testing and simulation-based design approaches further enabled a targeted evaluation of structural behavior.
For electronics integration, novel inorganic encapsulants were investigated with regard to thermal conductivity, weight, and reliability. To this end, processing concepts were developed for use in printed-circuit board-based electronic assemblies and for integration into lightweight structural elements, and new preparation and diagnostic methods for failure analysis were implemented. Reliability risks and aging mechanisms for electronic components using novel encapsulation materials were evaluated using custom-built functional prototypes. To this end, high-resolution analyses for microstructural characterization (ion beam techniques, SEM, EDX) were conducted, along with targeted thermal cycling tests, surface insulation resistance (SIR) tests, thermal shock tests, and passive moisture-heat tests, in order to track the material reactions taking place and elucidate degradation mechanisms.
This was complemented by concepts for integrated data acquisition and data-driven quality assurance, in which parameters – for example, from the injection molding machine, infrared oven, and robotic gripper system – are combined and made fully automatically available to specific user roles (e.g., setup technicians, injection molders, project managers), allowing for particularly deep insights into the relationships between process parameters and material properties.
“We were able to develop viable concepts for the plastics-compatible integration of high-density electronics, for alternative housing solutions, and for the thermal optimization of encapsulated systems. What is particularly valuable is that we have brought together materials development, process engineering, simulation, testing technology, and data analysis in a unified development approach. This has enabled us to lay the groundwork for industrial applications,” says Sandy Klengel, who also heads the subproject at Fraunhofer IMWS.
The project results open up a wide range of application possibilities, particularly for structural components in automobiles with integrated electronics and thermal management functions. In this way, “InThElekt” provides important impetus for the next generation of resource-efficient, more powerful, and industrially viable vehicle components, particularly in the field of e-mobility.
(October 13, 2026)
Fraunhofer Institute for Microstructure of Materials and Systems IMWS