Design and verification of an innovative handling system for electrodes in manufacturing lithium-ion battery cells

The automated handling of electrodes for manufacturing lithium-ion battery cells for automotive applications is a bottleneck of the productivity. Current handling methods are hardly efficient enough due to the usage of sequential pick-and-place operations. One possible solution for significantly increasing the productivity of handling electrodes is waiving setting and resetting movements of handling devices through the utilization of a continuous process flow. The continuous process flow is based on the continuous grasping, moving, positioning and orientating of electrodes for the provision of assembling a z-folded electrode-separator-compound for lithium-ion battery cells without setting and resetting movements. The presented design for moving, orientating and positioning electrodes is an integrant of an overall production system for assembling the electrode-separator-compound consisting out of grasping electrodes, unwinding separator and a subsequent continuous z-folding. Subsequent to the analysis of the requirements of an automated handling of non-rigid materials and specifically electrodes, a handling system is conceptually designed, prototypically realized and its performance is verified through various test series. The handling system requires a continuous input of single sheets of electrodes, which are initially not defined in terms of their individual orientation and position as well as their orientation and position in regard to their designated layer within the electrode-separator-compound. The handling system is based on a highly dynamic tactile movement and correction mechanism using several counter-rotating rolls with direct drives and an integrated sensor architecture for the real-time registration of orientation and position. Various test series are realized in which the process requirements of a damage-free handling and the handling accuracy simultaneous to the movement are registered and evaluated. (C) 2016 The Authors. Published by Elsevier B.V.