Development of a test method for investigating the leak tightness of hybrid joined battery housing connections

Electro mobility is considered an integral part of the energy transition in transport, as electric vehicles combined with regeneratively generated electrical energy have the potential to reduce CO ₂ emissions. At the heart of electric vehicles is the traction battery, which is located in the underbody area. It has to meet a wide range of requirements, which are accompanied by conflicting targets. The joints on the battery housing, which is preferably manufactured in a frame-multi-material design from extruded aluminum profiles and steel sheet, must meet additional requirements to guarantee the reliable connection of components and the safe transmission of forces. As the battery housing is located in the wet area of the vehicle, the joints must be leak-tight against penetrating moisture. Reliable testing and evaluation methods to estimate the tightness and long-term durability of the bonded joint under operation-relevant loads are currently missing and will be fundamentally developed. Therefore, leak tests were first carried out on test specimens on a laboratory scale in order to optimize the joining parameters. Finally, sample battery housings are manufactured on a laboratory scale and tested for leak tightness under cyclic mechanical loads.