Application report: Precise processes for the e-drive

With sensor expertise for high-voltage batteries

The BMW Group plant in Leipzig produces combustion engine and electric models. High-voltage batteries provide the drive energy for electric cars or hybrid vehicles. These are also manufactured on site. Sensor technology from Leuze contributes 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

Only after cell coating, module production and assembly is a high-voltage battery ready for use as an electric car. Leuze provides sensor support for cell coating and module production. Cell coating is the first step in high-voltage battery production. Each battery module consists of several cells. A Leuze MLC series safety light curtain protects the danger zone by muting to allow robots to unload these from large load carriers (LLCs). The robot places the cells on a conveyor belt. Here, switching light curtains from the CSL series detect whether these are positioned correctly. “They are well suited to monitoring large detection fields,” explains Jürgen Schweiß, KAM Automotive and Safety Application Specialist at Leuze.

High-gloss surfaces

Diffuse sensors from Leuze guarantee several functions: They detect the presence and position of the cells on the conveyor belt. PRK 25C series sensors reliably detect the cells’ glossy surface. The factory also uses HT25C series diffuse sensors with background suppression to detect cells. In cell coating, HT46CL series laser diffuse reflection sensors detect the cells and control the belt. Before the cells are loaded into an LLC, they are discharged through an MLC safety light curtain. The Leuze light curtains impress with their high resolution, protective field height and operating range. Another plus: a compact design and short safety distances. This allows them to be integrated even in tight installation spaces.

Perfectly positioned

Leuze laser diffuse reflection sensors monitor the unloading of the cells from an LLC into a module line from thyssenkrupp Automation Engineering. Each cell has a ‘heat shield’ pressed onto the long sides. Robots rotate the cells into the desired position. PRK 25 retro-reflective photoelectric sensors from Leuze detect the objects’ presence. ‘Stacking’ is where several cells for a battery module are placed next to each other. A pressure plate is attached to each end. PRK 25C sensors from Leuze detect the cells’ height and presence as well as the tool carriers’ status. Sensors are also active when the cell contact system is placed on the module. Another machine lifts the module so that the cell base coating can be checked: “Here, Leuze sensors help with height detection and at stop positions,” says Schweiß.

Everything in sync

Leuze sensors perform important tasks in the cell coating line and module production at the BMW Group plant in Leipzig: They also reliably detect objects with a high-gloss surface. In addition, safety technology from Leuze ensures seamless safety on machines and systems. Leuze thus contributes to efficient processes and is always on hand to support system operators in the design and implementation of sensor and safety solutions.