Meeting the need for battery power

Learn with ABB | September 27, 2023

The need for lithium-batteries of all sizes for a burgeoning number of applications is already outstripping supply. Therefore, every battery counts, as does every second devoted to making that battery.

Lithium-ion battery production is a technical challenge that is dependent on many processes working just right to ensure quality and consistency. Any flaws can severely impact plant availability and manufacturing throughput. This is because defects during manufacturing can not only shut down production lines when they are needed most, but can also potentially lead to safety issues for end-users and increase the risk of expensive product recalls.

That's why the fragile metal foils that form the core of the batteries require extremely careful handing at every stage of manufacturing, from initial coating and drying to calendering, cutting splitting, and final assembly.

The slightest imperfection at any stage can cause significant performance and safety issues in a finished battery. That's why it's vital to automate quality control and most aspects of production throughout with precision robotics to ensure safety, consistency, and productivity.

Accurately measuring and monitoring the movement of very thin, fast-moving coated metal foils presents specific challenges. Precision control and consistency of flatness and tension, for example, are essential to avoid the slightest component distortion, which can negatively impact battery performance, reliability, and safety.

This can be particularly challenging in factory environments, where equipment must be able to withstand a wide range of physical forces and, often, temperature extremes. Equipment calibration in such environments is crucial because if measurements go wrong, such imperfections can halt production for hours.

Any production stage such as coating, drying, calendering, slitting, and cell assembly can be compromised without accurate monitoring. For example, if production line tension from the start is too high, it creates a substantial risk of breaking the battery foil. Similarly, tension that is too low can result in uneven distribution of slurry on the metal substrate, which compromises battery performance and creates safety issues.

With the now-coated electrode foils passing at speeds of up to 80m/min through heated chambers with a temperature profile ranging from 50°C up to 160°C, the foil tension must be accurately measured both before and after drying to avoid breaks. The common challenge for many conventional measurement systems here is the need to monitor foil tension consistently and accurately at such elevated temperatures.

Assuming all goes well with coating and drying, the copper or aluminium foils are accelerated to 100m/min between a pair of rotating compression rollers for “calendering”, which compacts the applied coatings to ensure consistent thickness and reduce porosity. This process demands a precisely defined line pressure of up to 2,500N/mm. Again, if compaction pressure between the rollers is too high, the substrate and its coating can succumb to stress cracks.

Following calendering, each foil roll is cut into narrower rolls using rolling knives or a laser. This “slitting” process requires even higher linear speeds up to 150m/min. Once again, maintaining precision tension at those speeds is critical to achieving consistent quality.

Finally, tension control is also critical to ensuring proper alignment during final battery cell assembly.

Assembling cylindrical batteries requires winding. This process relies on both accurate alignment and tension control. An alternative assembly technique is stacking. Similar to winding, this method is also reliant on the accurate control of both alignment and tension throughout the process.

Measurement solutions for flatness, tension and thickness such as those offered by ABB combine high accuracy with minimal needs for calibration and maintenance. Their ability to provide accurate and reliable performance at every stage of battery production is central to quality and continuity, as well as contributing directly to the safety and performance of the finished product.

In this way, manufacturers have the reassurance that their production processes are making every second count when it comes to satisfying the world’s growing battery demand.

Find out more about ABB’s solutions for flatness, tension, and thickness measurement applications at 

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