A Guide to Making Highly Reproducible Li-Ion Single-Layer Pouch Cells for Academic Researchers
Matthew D. L. Garayt, Michel B. Johnson, Lauren Laidlaw, Mark A. McArthur, S. Trussler, Jessie Harlow, J. R. Dahn, Chongyin Yang
Abstract
With the growing number of academic researchers focused on lithium-ion batteries, the cell format of choice is often overlooked. Coin cells that utilize either a lithium metal or greatly oversized graphite negative electrode are common but can provide unrealistic testing results when compared to commercial pouch-type cells. Instead, single-layer pouch cells provide a more similar format to those used in industry while not requiring large amounts of active material. Moreover, their assembly process allows for better positive/negative electrode alignment, allowing for assembly of single-layer pouch cells without negative electrode overhang. This work presents a comparison between coin, single-layer pouch, and stacked pouch cells, and shows that single-layer pouch cells without overhang perform best. As well, an Ultra-High Precision Coulometry experiment is performed to show that excess negative or positive electrode coating is detrimental to cell performance. Finally, a guide to assembling reproducible single-layer pouch cells without overhang is presented.