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ElringKlinger, one of the world's leading systems partners to the automotive industry, automates the production of battery modules. KUKA developed the fully automated production line for this purpose.
The production plant, including all testing processes, is expected to produce around 300,000 battery modules per year. These will be used primarily in electric vehicles. But, the battery modules are designed to be flexible and can therefore also be used for other applications.
Starting in fall 2020, the battery modules are to be manufactured on the fully automated production line at ElringKlinger's plant in Thale, Germany. Electromobility is a new area of business of great strategic importance to ElringKlinger. As one of the first players within the German market, the company is investing in a large-volume, highly automated module production line.
We are deliberately breaking new ground with the battery module we have developed in-house. The closely linked development and industrialization of the product inevitably let us face the technical challenges.
The production line is divided into four main areas. In the first section the battery cells are tested and prepared for assembly. In the second plant section, a so-called raw module is produced by use of multiple battery cells. The cells are combined into a stack in the "merging 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 pressure 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 contacting 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 produced with miniature heat input. Laser welding technology offers the advantage 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 values 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 particles. Finally, a Data Matrix Code is lasered onto the battery module, which allows the battery module to be uniquely identified.
The special feature of the system is its modular design, which ensures flexibility in production. "The modular design was particularly important to us in order to be able to react fast and easily to our customer requirements.", says Mark Laderer. Battery modules of various sizes can be produced in PHEV2 format with twelve to twenty-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.
Our aim is to be able to serve both smaller customers with a finished product and established companies with an individual solution - the KUKA line enables us to do both.
The automation expert also paid special attention to the traceability: every component installed in the module is assigned to the final product together 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 in the production process can be identified faster and processes can be optimized. "Battery module production is more than just the mechanical assembly of individual parts.", explains Max Fluhrer, Project Manager in the Battery Solutions division of KUKA.
The production line must be able to react individually to batch quality, enable flexible product configurations and ensure the 100% traceability mentioned above. We are proud to have been chosen by ElringKlinger as a partner for this demanding task.
