Safe, Inexpensive Sodium-Ion Batteries for Naval Applications

The energy needs of the modern U.S. military are dynamic and every growing. The need for safe, reliable, inexpensive energy storage is of paramount importance to maintain mission effectiveness. While lithium-ion batteries offer relatively high energy densities, they carry inherent safety risks. Legacy battery chemistries, like Pb-acid and Ni-Cd are reliable but limited in their energy density. Furthermore, the critical resources needed to produce these systems are vulnerable to supply chain disruptions from foreign adversaries. Sodium-ion batteries (SIBs) present a promising alternative in that they have higher energy density than legacy chemistries, have good inherent safety, and can be made from earth abundant materials that can be produced domestically. For these reasons, CRG believes that SIBs present a promising battery alternative for naval applications. CRG proposes to use cells developed and built by Unigrid, a company in San Diego, CA, to develop a demonstrator battery concept to showcase the potential of SIBs for the U.S. Navy. Unigrid cells are commercially available with excellent cycle life (3000 cycles to 80% retention) and the ability to repeatedly fast charge in 15 minutes (4C). Additionally, the cells have a wide operational temperature window of -40 ∞C to 60 ∞C. Most importantly, in accelerated rate calorimetry test (ARC) the cells do not experience thermal runaway, making them significantly safer than traditional lithium-ion chemistries.Ý CRG proposes to leverage the excellent performance of the Unigrid cells into a prototype operational battery to demonstrate the untapped potential of SIBs in naval applications.Ý