The team at South 8 Technologies (South 8) is the first to develop a novel and patented Liquefied Gas Electrolyte, LiGas®, chemistry for advanced Lithium-ion batteries with superior cost performance metrics and value propositions that make it uniquely suited to the future of energy storage systems and electric vehicles. The proposed non-hazardous chemistry not only lowers the cost to California ratepayers through the operational life of the electric vehicle or energy storage system due to increased cell performance, but also lowers recycling costs at end-of-life. The improved safety inherent to the cell chemistry furthermore reduces potential for cell-to-cell thermal propagation, which lowers downtime and improves grid resilience. Lastly, the innovation improves fast charge capabilities and the operation temperature range of the cell.
Through the course of this California Energy Commission project, the team at South 8 improved cycle life (>2,000 cycles), temperature (operation from –76°F [–60°C] to 140°F [60°C]), and power performance (2C-Rate) of the LiGas technology while also reducing the cost, vapor pressure, and global warming potential of the electrolyte chemistry. These cell level improvements were made by modifying the electrolyte composition, improving from South 8’s “Gen 1” chemistry at the start of the project and finishing with the team’s “Gen 3” chemistry.
During the duration of the project, further improvements were made to the cell form-factor hardware (mechanical packaging), reducing the overall cell height (9-percent reduction) and mass (5-percent reduction) from prior to the contract start. An improved LiGas injection system was also designed and implemented. The semi-manual system is now capable of filling an individual cell within nine minutes (including handling, vacuum, injection, and seal), and the time is being further reduced. The actual wetting time within the cell was measured to be a maximum of five minutes but was essentially complete within 60 seconds.
Author(s)
Cyrus Rustomji CSO, Jungwoo Lee CTO, South 8 Technologies, Inc.
