Energy Storage: Advanced Battery Electrode Coating

Energy Storage - Case Study

Slot-Die Tension Web Coating
Engineering a Better Way to Manufacture Battery Electrodes

Slot-Die Tension Web Coating
Simultaneous two-sided coating delivers twice the production volume compared to single-side coaters. The dual coating method, in combination with coating rheology and GigaCoaterTM machine properties, maximizes production time and delivers in-line quality control.

Problem

An electrode manufacturer was looking for a better way to do electrode coating and requested a collaborative effort with B&W MEGTEC in an effort to develop a simultaneous two-sided coating and drying process that did not require a vertical web path through the dryer. The potential customer approached B&W MEGTEC because they were familiar with its patented air flotation drying equipment and R&D Pilot Line capabilities.

The traditional tandem coating process is characterized by coating and drying one side of the current collector, then re-running the foil through the entire coating and drying process for the second side of the foil. Tandem coating also requires a longer manufacturing line that takes up more factory space.

Technology previously developed in Asia for simultaneous two-sided battery electrode coating dictated the need for a vertical air flotation dryer. However, the customer did not want a vertical web-path dryer because of the substantial building height required and the increased difficulty in providing operator access for tending purposes compared to a dryer with a horizontal web path.

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B&W MEGTEC GigaCoaterTM
Full-scale lithium-ion battery electrode coating line on the B&W MEGTEC GigaCoater coating machine.

tensioned-web coating process
In the tensioned-web coating process, a slot-die with a backing roll applies the electrode coating to the topside of the web, while the back side is simultaneously coated in the horizontal tensioned web mode just prior to entering the dryer.

Solution
 
The engineering goal was to perfect a simultaneous two-sided coating method that uses a horizontal air flotation dryer instead of a vertical dryer. B&W MEGTEC engineering and R&D teams developed a new coating concept and refined it through extensive testing on the B&W MEGTEC R&D Pilot Line.
 
The new B&W MEGTEC process required just a single pass. There was only one coating station, one dryer, and all equipment was located on the same level of the facility, all within a small footprint compared to a traditional tandem coating line.

Potential benefits of the single-pass feature of the B&W MEGTEC slot-die tension web coating line include:
 
  • Reduced electrode manufacturing costs
  • Effective doubling of production volume without changing line speed
  • Reduced waste
  • Lower capital and operating costs
  • Improved overall production.