Precision to the point

Height measurement of electrode magazines in battery cell production    

In the cell stacking systems in battery cell production, it is particularly important to make the handling of electrodes as process-reliable as possible. In a joint project with a renowned research institute, SICK implemented such a solution for the height measurement of electrode magazines using the OD200 displacement sensor. This was made possible by the many advantages that the OD200 offers in this application with regard to precision and measurement stability.

The OD200 is a compact laser distance sensor for measuring short ranges. For users, the innovative distance sensor represents a significant upgrade from the previous market standard, as confirmed by the customer: "With its newly-developed measurement core with a highly dynamic receiver unit and optimized optical system, the OD200 miniature displacement sensor offers the same level of ruggedness and reliability normally reserved for high-end devices. The sensor thereby ensures a high measurement stability and a reproducible detection and switching behavior." 

This was especially required in one process step – a cell stacking system for battery cell production – where the challenge lays in designing a process-reliable automatic gripping system for handling the electrodes. The vacuum gripper needs to be precisely stopped and positioned at the correct location for picking up the top electrode.The OD200 measures the stack height while doing so. Other important aspects were ease of integration of the sensor, simple adjustment of the sensor, and low maintenance costs during operation.

Point measurement directly on the electrode surface: precise, reproducible, reliable

When SICK presented the OD200 to the research institute, the initial thoughts of using a photoelectric retro-reflective sensor for the height measurement were quickly discarded. "The OD200 is a standalone solution in a single device that requires no reflector and is easy to adjust," confirms the customer and adds: "Furthermore, the sensor can perform a point measurement on the electrode surface precisely at the location where the gripper picks up the electrode, so any warping of the electrode is not an issue. And it can do so at almost any alignment angle, which is truly impressive."

Also advantageous to the user is the precision and reproducibility of the measurements. "The reason why only minimal measurement deviations arise is first and foremost the newly-developed triangulation measurement core with powerful evaluation algorithms," says Michael Kiss, Strategic Product Manager at SICK. "This enables it to not only solve the problem at the research institute but also measurements on highly reflective, very dark and irregular surfaces."

The reliability and reproducibility of the OD200 is also largely attributable to the modified optical system. "We further optimized it with regard to the geometry and homogeneity of the light spot as well as ambient light immunity. Consequently, significantly fewer faults due to false measurements and missing signals occur compared to market standard devices. This means less downtimes, less setup and maintenance costs, and more productivity." 

The OD200 was able to be quickly and easily implemented in the cell stacking system with no significant adjustment and calibration effort thanks in no small part to its miniature housing and standard connectivity options. Since it was commissioned, the sensor has been performing height measurements of the electrode stack without problems, simply and reproducibly.

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