Modern battery technologies play an important role in numerous fields of application, from electric vehicles and energy storage systems to mobile devices such as smartphones. A high-precision battery production process is essential to meet the increasing demand and to keep the performance at a high level. In this context, state-of-the-art sensor technology is used.
 

High-Precision Solutions in Battery Production

Sensor specialist Micro-Epsilon offers high-precision solutions for numerous applications in battery production. These range from individual sensors to complete sensor systems, from inline thickness measurement and precise machine monitoring to 3D surface inspection. The measurement technologies are used by leading battery manufacturers and automotive groups. The sensor signals can be calculated, evaluated, or analyzed using turnkey solutions.
 

Applications in Production Steps

Sensors and measuring systems are used in automated processes in all production steps of anodes and cathodes, separators, and active material. They measure with high precision during coating, calendering, assembly, and even forming. Micro-Epsilon offers numerous solutions for electrode film coating lines in particular. The sensor systems are used for both wet and dry coating processes. Coated copper film can be monitored in the same way as aluminum film. Process-critical parameters include the coating thickness, thickness of the films, web edge position, and coil unwinding, as well as the monitoring of the coating application at the edges.
 

Thickness Measurement of Battery Film

Capacitive sensors have proven themselves in inline thickness measurement of battery film. These have a larger measuring spot, which means an inhomogeneous structure can be compensated for via the area integration of the sensor. In addition, the capacitive sensors can be used at high process temperatures of up to 200°C. Thanks to integrated temperature compensation, they deliver stable measurement values in the sub-micrometer range.
 

Two-sided Thickness Measurement for Electrode Coating

With double-sided thickness measurement, two sensors from the Optoncdt 1900 LL series are arranged opposite each other, each one measuring the distance to the battery film. Based on synchronization combined with the precise sensor alignment, high measurement accuracy and measuring rates are achieved. The thickness values can be used to control the coating application and for quality assurance.
 

Distance Sensors for Roller Gap Control

State-of-the-art inductive sensors are normally used to monitor and control calender and coating rollers. Instead, Micro-Epsilon uses capacitive sensors, which are available in various designs and detect the roller gap with micrometer accuracy. These compact sensors can be integrated into confined installation spaces to measure directly against the rollers or the roller suspension.
 

Process-reliable Distinction of Black Tones

In the manufacturing process of lithium-ion batteries, carrier films are combined with an anode and a cathode to form an energy cell. The Colorsensor CFO200 color measuring system in conjunction with the CFS2-M11 circular sensor reliably solves this measurement task and makes it possible to distinguish fine color nuances. The measurement takes place in real-time, with high precision and high speed.
 

2D/3D Sensors for Electrode and Battery Production

3D sensors from Micro-Epsilon are used for assembly monitoring and for 3D inspection of coated films. 3D laser scanners are used for continuous belt inspection, while 3D snapshot sensors are used for stop-and-go measurements with extremely high precision. The 3D sensors allow stable measurement with high resolution and detect flaws on the smallest of shapes, such as spalling and inclusions.
 

3D Monitoring of the Coating Application on the Belt Edges

Electrodes must be coated with extreme precision. Therefore, laser scanners from Micro-Epsilon inspect the coating profile on the edge. This is how anomalies of the coating and undulations are detected. These 3D laser scanners are characterized by high dynamics, precision, and their compact size.
 

Web Edge Control of Electrode Film

During the production of battery cells, electrode and separator films must be guided reliably. Optical Optocontrol micrometers detect the required edge position for web edge control. Operating several micrometers enables the concurrent detection of the web width. Due to their high measuring rate, Optocontrol micrometers are also suitable for monitoring dynamic production processes.
 

Inline Systems for Measuring the Strip Thickness

The Thicknessgauge sensor system is used for inline thickness measurement of strip materials. Equipped with a white light interferometer, it detects thin coatings from 10 µm on plastic films with sub-micrometer accuracy. Several models with different sensor types, measuring ranges, and measuring widths are available from Micro-Epsilon for precise thickness measurement.
 

Inline Thickness Measurement of Battery Film

The Thicknesscontrol measuring system is used for inline thickness measurement of coated battery film and impresses with long-term stable measurements. It consists of one or two robust measuring frames, each of which can be equipped with up to four thickness measuring tracks according to customer requirements.
 

Conclusion

The use of sensor systems in battery production increases efficiency and quality and conserves resources. Micro-Epsilon develops, produces, and distributes sensors, measuring systems, and customer-specific solutions. The wide range of products is based on different measuring principles and is tailored to the high requirements of battery production. It is ideal for monitoring production processes in battery cell manufacturing. Various measuring methods are available for measuring the thickness of the battery film, which are optimized for the respective process steps.