Practical Considerations in the Development of 3 and 15 Ah Rechargeable Lithium Pouch Cells

Commercially available Li-ion batteries using graphite or graphite-silicon blended anodes are currently approaching a cell level specific energy of 350 Wh kg−1. EaglePicher previously demonstrated a 2 Ah rechargeable pouch with a lithium metal anode that delivered 375 Wh kg−1 (Crowther, Owen. "Solving Barriers to Commercialization of Cells with Lithium Metal Anodes." 236th ECS Meeting (October 13-17, 2019). ECS, 2019). Further improvements to chemistry and cell design resulted in a 3 Ah pouch with longer cycle life and specific energies above 400 Wh kg−1 (Crowther, Owen. "Rechargeable Lithium Metal Pouch Cell Development." ECS Meeting Abstracts. No. 1. IOP Publishing, 2021). This paper will discuss several new areas that resulted in improved cell performance such as increasing the tab size, optimizing the electrolyte type and amount, and introducing excess lithium metal into the anode. Figure 1 demonstrates the rate capability of the cell with larger tabs to minimize the ohmic resistance. The cell with delivers ~425 Wh kg−1 at low rate and >300 Wh kg−1 at a 6.6C rate. The maximum continuous rate for the cell with the original tabs was 1C. Finally, the initial prototype performance of a 15 Ah rechargeable lithium pouch cell with a specific energy >500 Wh kg−1 will be highlighted. Figure 1