The design of the modules determines the geometry flexibility and the electrical properties of the entire pack, since this is the smallest module with all functions, eg battery management, cooling and electrical connection of the individual cells. For example, round cells of the type 18650 are currently preferably contacted by conventional ultrasonic wire bonding. However, the power cross-sections are physically limited.
Thicker wires require a significantly higher ultrasonic power, but they can not be coupled to the compliant surfaces, especially on the positive pole of the cells, in a process-safe manner. The same applies to cell and module designs, in which thicker wire cross-sections are processed. From the point of view of cost reduction, it is highly attractive to have a flexible modular design with different cell numbers, and to provide a connection technology for significantly larger line cross sections, with which an individual battery pack can be manufactured depending on the power and space requirements. Particularly important is a joining technique which allows both large cross-sections for punched grid connections as well as individual single connections with high reliability, flexibility and low costs. The laser bonding of strips with cross sections of approximately 2 × 0.4 mm² to about 10 × 0.8 mm² is the most suitable technology for these requirements for these requirements for different materials and system combinations.
With the modular concept of module construction and joining and contacting technologies, the flexible choice of ribbon bonding and punching lattices can be used to implement production systems for the construction of continuous process chains from manufacture through the small series to large series with a comprehensive machine and system concept. The laser bonding technology used with novel fault-tolerant and robust process batches allows the use of a large contact geometry spectrum with a wide degree of material independence and a 100% control of the joining process via suitable in-situ measurements. This takes account of the requirements of battery manufacture for electromobility, to provide a safe construction technique for large thermal and mechanical loads and high service life.
With these concepts, the project contributes to reducing the overall system costs of electric mobility and to shorten the time from product development to the launch of e-vehicles through flexible, robust and scalable production methods.