OEM&Lieferant Ausgabe 2/2020

103 supply a customer from southern Germany who has contracted ElringKlinger to supply battery modules for its solar vehicle. Battery module production over four plant areas The production line is divided into four main areas. In the first section the battery cells are tested and prepared for assembly. In the sec- ond plant section, a so-called raw module is produced by use of multiple battery cells. The cells are combined into a stack in the „merg- ing device“. This stack is pressed together with the pressure plates, which are positioned at the ends of the stack, and the end plates, which are placed at the sides of the battery cells. Using a complex laser system and laser op-tics guided by a KUKA KR240 industrial robot, the end plates are welded to the pres- sure plates of the cell stacks, thus completing the raw module. Depending on requirements, twelve to twenty-four battery cells are joined together to form a battery module. In the third section of the production line, the battery modules are electrically connected and measured. For this purpose, the cell con- tacting system is put on and welded to the contacts of each individual battery cell. The particular challenges here are the very tight component and joining tolerances as well as the special requirements for laser contact welding, because a large contact area must be reliably producedwithminiature heat input. Laser welding technology offers the advan- tage of being contact-free and force-free, and at the same time it is fast, precise, wear-free and easy to control. The laser scanning optics used ensure an optimum contact result, which allows the geometry of the welding seams to be designed flexibly. In the fourth and last area of the production line, an automated electrical and mechanical end of line test of the battery modules takes place. Among other things, the insulation val- ues are tested here for a voltage resistance of up to five kilovolts. This test ensures that persons and objects are protected against electrical flashovers and leakage currents. The battery housing is then covered with a heat-sealed lid to make the battery module safe to touch and protect it from dust parti- cles. Finally, a DataMatrix Code is lasered onto the battery module, which allows the battery module to be uniquely identified. Modular design ensures flexibility The special feature of the system is its modular design, which ensures flexibility in production. „The modular design was particularly import- ant to us in order to be able to react fast and easily to our customer requirements,” says Laderer. „Our aim is to be able to serve both smaller customers with a finished product and established companies with an individual solution.” Battery modules of various sizes can be pro- duced in PHEV2 format with twelve to twen- ty-four battery cells per unit. In addition, the way in which the individual battery cells are inter-connected within the battery module can be varied. Traceability for complete retraceability Laderer also paid special attention to the traceability: every component installed in the module is assigned to the final product to- gether with process parameters. This means that even years later the customer can see which components have been installed in each individual battery module and trace all steps of the production process. In addition, errors can be identified faster and processes can be optimized. „Battery module produc- tion is more than just the mechanical assem- bly of individual parts,” explains Max Fluhrer, Project Manager in the Battery Solutions di- vision at the plant manufacturing company KUKA. „The production line must be able to react individually to batch quality, enable flexible product configurations and ensure the 100% traceabilitymentioned above. We are proud to have been chosen by ElringKlinger as a partner for this demanding task,” adds Fluhrer. *A contribution by ElringKlinger AG ElringKlinger www.elringklinger.com Website ElringKlinger Mark Laderer Director Production Battery Technology & E-Mobility mark.laderer@elringklinger.com