Precise processes for the e-drive





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With sensor expertise for high-voltage batteries

One of the most cutting-edge car manufacturing factories in the world is located in the north of the city of Leipzig: BMW Group Plant Leipzig. The Saxony-based site produces both combustion engine and electric models in parallel. E-mobility requires high-voltage batteries to supply the BMW Group’s electric cars or hybrid vehicles with the necessary drive energy. The automotive group also manufactures these on site. Sensor technology from Leuze makes an important contribution to an efficient and safe production line process, implemented by Schaeffler Special Machinery, the Schaeffler Group’s mechanical engineering company.





It all starts with the cell

Three successive production steps are required from the first component to the finished high-voltage battery: Only after cell coating, module production and finally assembly is a high-voltage battery ready for use as an electric vehicle’s energy supply. Precision and reliable processes are essential at every step. Leuze supports this with sensor solutions in cell coating and module production. Cell coating is the first step in high-voltage battery production. Each battery module consists of several cells. These are delivered to BMW in large load carriers (LLC). So that the LLCs can be unloaded automatically by robot, a Leuze safety light curtain from the MLC series secures the danger zone to prevent people from entering. Muting ensures that only the LLC can pass through. The robot always unloads 16 cells at the same time and places them on a conveyor belt. Here, horizontally installed switching light curtains from the CSL series detect whether the cells are positioned correctly. “The switching light curtains are very well suited to monitoring large detection fields,” explains Jürgen Schweiß, KAM-Automotive and Safety Application Specialist at Leuze. In addition, thanks to quick parameterization and simple handling, they are usually more cost-efficient than imaging methods.



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A robot places the cells removed from a large load carrier onto the conveyor belt. Here, horizontally installed switching light curtains from the CSL series detect whether the cells are positioned correctly.



High-gloss surfaces

Diffuse sensors from Leuze ensure several functions at different points: “Sensors mounted on the belt detect the presence and correct position of the cells. If they are present and correctly positioned, the process continues,” says Jürgen Schweiß. The advantage of the PRK 25C series sensors: They detect the high-gloss surface of the cells with absolute reliability. In addition, the transmitter and receiver are located in the same housing. This means that applications can be implemented conveniently and cost-effectively, even in confined installation situations. The sensor variant optimized for reflective objects achieves operating ranges of up to 16 meters. System operators can also easily configure the sensitivity, as they can be quickly and easily adjusted with their bright light spot. In addition to the PRK 25C sensors with reflector, the HT25C series diffuse sensors with background suppression are also used to detect individual cells.



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Advantage of using Leuze 25C series sensors: They detect the high-gloss surface of the cells with absolute reliability.



A compact approach to safety

Sensor technology from Leuze keeps an eye on every aspect of cell coating: Laser diffuse reflection sensors from the HT46CL series detect the individual cells and control the conveyor – with maximum detection reliability thanks to background suppression. Before the cells are loaded into a LLC, they are discharged through a Leuze MLC safety light curtain. Advantages of Leuze light curtains: They not only score points with their high resolution, protective field height and operating range, as Jürgen Schweiß emphasizes: “With light curtains, a compact design and short safety distances are often also important. Only then can they be easily integrated into tight installation situations.”



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The blue-colored cells on their way to the next production step. Sensor technology from Leuze always has everything in view. The HT46CL background suppression sensors detect the individual cells and control the conveyor belt.
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To ensure that the large load carriers (LLC) can be loaded and unloaded safely, a Leuze safety light curtain from the MLC series secures the danger zone to prevent people from entering. Muting ensures that only the LLC can pass through.



Perfectly positioned

Leuze laser diffuse reflection light scanners also monitor the unloading of the cells from a LLC into a module line from thyssenkrupp Automation Engineering. Each cell also receives a so-called “heat shield” – a protective heat insulation – which is pressed onto the long sides. Robots rotate the cells into the desired position on a circular machine. Sensors from Leuze also provide support here: PRK 25 retro-reflective photoelectric sensors detect the presence of the objects. The heat shield process runs in parallel at two stations in order to achieve a high throughput time.



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When the cells are separated, sensors detect the positions of the objects. This is a prerequisite for an automated process.
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At this station, each cell is given a ‘heat shield’ – protective heat insulation – which is pressed onto the long sides. Leuze PRK 25 retro-reflective photoelectric sensors detect the presence of the objects.



From stacking to the module

In “stacking”, as experts call the stacking of several cells to form a battery module, several cells are placed next to each other, and a pressure plate is attached to each end. PRK 25C sensors from Leuze detect the height and presence of the cells and recognize whether the tool carriers are closed correctly. Sensors are also used when placing the cell contact system (ZKS) on the module. A machine lifts the entire module so that the coating on the cell base can be checked: “Here, Leuze sensors provide support for height detection and at stop positions, among other things,” says Schweiß.



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A double module including cell contact system on the top. In the final step, a cooling unit is added. Finally, the double module goes into assembly. Sensors from Leuze detect the position of the modules on the belt.



Everything in sync

Leuze sensors perform important tasks in the cell coating line and module production at the BMW Group plant in Leipzig: They reliably detect objects and also meet high requirements, such as the detection of high-gloss surfaces. In addition, safety technology from Leuze ensures seamless safety on machines and systems. The Sensor People thus contribute to efficient processes in the automotive industry and are always on hand to support system operators in the design and implementation of sensor and safety solutions.





The author

Martina Schili
Manager Corporate Communications

Leuze electronic GmbH + Co. KG 
In der Braike 1
73277 Owen

Telephone: +49 7021 573-116
Email: martina.schili@leuze.com

Web: www.leuze.com





Leuze

More than 60 years of experience have made Leuze a real expert in innovative and efficient sensor and safety solutions for automation technology. Today there are more than 1600 Sensor People around the world who are working with curiosity, passion and determination for progress and transformation. Their motivation is the continued success of their customers in an ever-changing industry. Leuze offers its customers a tailored competitive advantage through intuitive, reliable solutions for safe and non-safe position detection. For example, switching and measuring sensors, identification systems, solutions for data transmission and image processing. As a safety expert, the family business also focuses on components, services and solutions for occupational safety. Thanks to their broad and in-depth application expertise in the machine and system construction, the Sensor People are a competent and flexible partner for customers with a wide range of industrial requirements. www.leuze.com