Concept for modelling the influence of electrode corrugation after calendering on stacking accuracy in battery cell production

Due to the complex process chain in battery cell production, effects of processes on subsequent processes must be evaluated. As challenge in calendering electrodes, corrugation can be observed depending on adjusted parameters. To evaluate the corrugation with regard to the subsequent stacking process accuracy, a concept for modelling the process chain calendering - separation - single sheet stacking is presented. First, an experimental approach for modelling the calendering impact on the electrode sheet geometry after separation is suggested. Finally, a FEM simulation approach for the single sheet stacking process is presented, which is suitable to model impacts from previous processes

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Intelligent Anomaly Detection of Machine Tools based on Mean Shift Clustering

For a fault detection of machine tools, fixed intervention thresholds are usually necessary. In order to provide an autonomous anomaly detection without the need for fixed limits, recurring patterns must be detected in the signal data. This paper presents an approach for online pattern recognition on NC Code based on mean shift clustering that will be matched with drive signals. The intelligent fault detection system learns individual intervention thresholds based on the prevailing machining patterns. Using a self-organizing map, data captured during the machine’s operation are assigned to a normal or malfunction state

Production-oriented design of electric traction drives with hairpin winding

In recent years, the manufacturing of stators by hairpin technology has proven its ability to fulfill the requirements on quality, productivity and robustness of traction drive applications in automotive industry. However, the uncertainty and necessity of rapid product development despite fuzzy target systems still cause that processes, machines and equipment – as well as the electric design – are often in an imperfect prototype stage at the start of production ramp-up. Due to the complex interdependencies between the stator components in combination with a high sensitivity of the overall process reliability to minor adjustments of stator design features, possible production-related weaknesses in design are often recognized first in the prototype stage of the production system. In order to reduce the economic risk resulting from these volatile technological conditions, production-oriented design based on numerical simulation methods can be applied from the beginning of product development. Therefore, several techniques for numerical process modeling are presented in this paper as possibilities to consider manufacturing constraints in an early stage of product development. For this purpose, the influence of wire dimensions on the forming process of hairpin coils is investigated using the example of rotary bending as well as the twisting process of a full stator by finite element simulations. Furthermore, a numerical approach to investigate the influence of heat input during laser welding of hairpin coils on the required stripping length is introduced

Investigation of the Forming Behavior of Copper Wires for the Compaction of Windings for Electric Machines

To meet the increasing demand for highly efficient electric traction drives, the compact winding process has been developed at the wbk Institute of Production Science. One key element of the process chain is the compaction of the round wire stator windings. In order to enable an estimation of the sensitivities of the influencing factors, a simplified finite element simulation model was set up in the present work. In the calculations, the number of wire layers, the layer structure and the punch stroke were selected as factors with three levels each. The evaluation was performed by means of false color images and the maximum strains and stresses in the section plane of the slots