Structural optimization through function integration Designing buildings in such a way that they fulfil their functions - in particular weather protection and energy supply - at low economic and ecological cost is an important task in the direction of a sustainable building market. The production of prefabricated parts often leads to economic and ecological advantages. These advantages should also be transferred to the function of energy supply by integrating renewable energy technologies into the precast production process. Within the scope of the presented investigations, component designs for embedding electrical energy storage devices in precast parts are presented which were examined with regard to load-bearing capacity and initial cracking behaviour. A cassette construction made of textile concrete proved to be particularly advantageous with regard to the exchangeability of the electrical storage elements, their load-bearing behaviour and the storage volume provided.