A firm grip on non-rigid parts: KR CYBERTECH automates battery pack assembly

They are quiet, increasingly use electricity from renewable energy sources, cause fewer CO₂ emissions and entail lower costs for repair and maintenance. Electric vehicles are the future. It is estimated that more than 27 million plug-in hybrids and e-cars are currently driving around the world. And when numerous major states put the brakes on the registration of internal combustion vehicles between 2030 and 2035, this number will rise significantly. KUKA recognized the potential of e-mobility early on. Since 2014, the automation specialist from Augsburg has been optimizing its product portfolio to meet the special requirements that have to be met in the production of electronic components for the automotive industry. Liebherr-Verzahntechnik GmbH in Kempten is now also benefiting from this. There, with the help of KUKA robots, an application has been created that can offer manufacturers of electric vehicles and their suppliers greater safety and higher productivity. After all, what would an electric car be without its core component, the battery?

Most process steps in battery production are already automated today in order to meet the requirements of the automotive industry in terms of cycle times, quantities, quality and production costs, among others. The shortage of skilled workers is also driving the strong trend toward automation. Fewer and fewer skilled workers can be found who are willing to take on such a monotonous, physically stressful and at the same time demanding task. The company KOSTAL Kontakt Systeme GmbH from Lüdenscheid, which has been producing and selling connectors for the automotive industry since 1938, recognized a gap in the market here. It developed a connector suitable for both manual mating and automation. Martin Wolter, Group Manager for Development at KOSTAL Kontakt Systeme, reports: “Safety plays a very important role here – since these are high-voltage contacts, they must be touch-proof. This is comparable to a socket outlet; here the electrical contacts are also protected against accidental contact with fingers. The difference is that the plug connection in the vehicle is exposed to vibration and both high and low temperatures. Our system is very robust and reliably transmits power throughout its service life under varying loads.”

Automating the handling of flexible parts by machines is still a major challenge: for example, elastic cables, which can twist in any direction, are difficult for robots to grip. Based on the KR CYBERTECH nano ARC HW, the company from Kempten has developed a special gripper that removes the cables from a blister. Since the cable is not pre-positioned with sufficient accuracy inside the blister, a 2D camera is used: it helps to determine the exact gripping positions on the flexible cable and to position the module connector at the end of the cable precisely over the connector counterpart.

Because the connector must be handled with care, the mating process has been decoupled for smooth operation. A spring assembly controls the force applied to the connector and the connector position assurance (CPA). A pneumatic cylinder then presses the connector into the counterpart. This spring assembly compresses until the force torque of 70 newton meters is reached and the end position sensor is triggered. At the same time, the spring-loaded locking pin presses the CPA down. This locks the CPA, the plug is inserted in a process-safe manner and the gripper can move upwards again. In contrast to other automation experts, Liebherr deliberately does not solve the plugging process of the flexible cables via trial-and-error processes. Every grip must fit. The reason for this is that the technology must be suitable for series production and must be able to meet strict cycle times. This has worked even better than good: Instead of the prescribed 17 seconds, the system achieved a cycle time of eleven seconds.

The automation specialist from Augsburg is prepared for this and the company’s portfolio includes ESD-protected robots as well as robots certified for cleanrooms and dry rooms. Viktor Bayrhof of Liebherr sees it in the same way. “High-voltage battery systems are the most expensive component of an electric vehicle,” says Bayrhof. “To produce these batteries economically in large quantities, automation plays a key role.” The solution developed by Liebherr, KOSTAL and KUKA can ensure companies' competitiveness even in turbulent times. It gives them permanent control over their production – including the flexible parts.