It takes an electrician with additional high-voltage qualifications several hours to completely disassemble an electric car battery. 'That is time that a recycling company simply doesn’t have, given the shortage of skilled workers and the millions of used batteries expected in the coming years,' emphasises Viktor Bayrhof, Product Manager at Liebherr-Verzahntechnik in Kempten.
That is why Liebherr has developed a robotic disassembly system that can even cope with the often chaotic mix of screws, whether Torx or hexagonal. The "LHDismantle" automated screw removal system is equipped with an automated tool changer and disposes of the screws using a pick-and-place gripper or a vacuum system.
'System operators don’t even need to have any knowledge of robotics or automation because operating the system requires no programming or teach-in skills, explains Daniel Reischmann from the Technical Sales Team for Automation and E-Mobility at Liebherr. The company can integrate the robot cell as part of a system designed to completely disassemble the components of a battery pack.
The servo-pneumatic position controller CMAD enables robot grippers to apply a particular force in both horizontal and vertical orientations with an accuracy of 0.2 mm. Thanks to its integrated position detection, the position controller CMAD can maintain a constant force even when the position in space changes. Liebherr also uses this feature in the LHDismantle, as the screws on a vehicle battery are fitted not only vertically but also horizontally. Looking ahead, this solution will also enable the automation of other screwing processes, for example as part of the complete vehicle disassembly.
Pneumatic drives are particularly popular for use in robots and in front-end applications. Thanks to their low weight combined with their high power density, they are ideally suited to these end-of-arm applications. What has limited the use of pneumatic drives up to now is the fact that they could only be operated in open-loop mode. The CMAD, with its piezo valves, is now capable of controlling even small pneumatic cylinders.
That means it has the same control characteristics as an electric system but weighs much less. The piezo valves can be operated in both position control and force control modes. The position controller CMAD is complemented by the proportional-pressure regulator VEAB, with its precise control capabilities at low flow rates, the flexible valve terminal VTUX, and a wide range of pneumatic cylinders.
'The development of the position controller CMAD came at exactly the right time. It allowed us to get rid of with the vision system we had been using previously – which was not always reliable – as we continued to develop the system,' explained Jan Pollmann, Head of Development at Liebherr. 'The experts at the Festo Experience Centre (FEC) in Esslingen were really great, as they helped us to thoroughly test the planned solution.'
Thanks to the automated system LHDismantle from Liebherr, battery recycling companies are prepared for the future, as the need for action is pressing. By 2030 the volume of end-of-life batteries from electric vehicles in the EU is expected to increase more than tenfold. This makes it possible to recover valuable raw materials such as lithium, cobalt and nickel, and, thanks to automation, electric vehicle manufacturers are able to meet the recycling targets set by the EU at a reasonable cost.