Ex-Ante Process-FMEA for Hairpin Stator Production by Early Prototypical Production Concepts

Abstract

The worldwide demand for electric vehicles is on the rise and production capacities for electric powertrains need to keep pace with this development. The innovative hairpin stator technology, in which solid copper bars are used instead of flexible round wire for coil production, promises valuable unique selling points on both the product and process side, but also confronts automotive manufacturers and plant manufacturers with major challenges. Due to the cost-intensive and only slightly variant flexible production lines, the optimum product and process concepts must be developed and defined at an early stage. The key for industrialization of hairpin stators is an effective process development and technology selection, especially for the necessary bending and contacting technologies. To systematically break down the technological challenges of process development, a process failure mode and effects analysis (FMEA) is used in this paper with the aim of a scalable, ramp-up-optimized and economical production line. Therefore, the FMEA-method is applied to the partially unknown process technologies of hairpin stators through the investigation of results from early prototypical production concepts especially for the necessary bending and contacting technologies. The analysis lists processes with possibly insufficient process capabilities due to process interdependencies that have been derived using early production prototypes for hairpin stators. In conclusion, this paper presents a method that applies the FMEA-method to early prototypical production concepts of hairpin stators and makes it possible to integrate the results into the final process development and technology selection.