A Novel Cell Architecture for Lithium Ion Cell Provides Improved Safety Performance and Offers Lower Weight and Lower Cost

摘要

Soteria Battery Innovation Group has developed a novel cell architecture for lithium ion batteries that will greatly improve safety while also reducing weight and improving the manufacturing cost. Using traditional materials, the lithium ion cells are subject to safety events if an internal short develops or is caused by cell damage. When an internal short develops, the energy of the cell pours through the current collectors into the short, generating heat which causes the polyolefin separators to melt and shrink. This shrinkage increases the size of the short, increasing the flow of energy into the cell and generating more heat in a vicious cycle until thermal runaway occurs. Soteria has developed a novel cell architecture with two components. The first part is a thermally stable nano-fiber nonwoven separator. In case of a defect creating a short, this separator will never melt or shrink by heat and hence will not make the internal short worse. The second part is a current collector made from metallized films which melts and shrinks away from the internal short, breaking the circuit and stopping the flow of energy into the cell. The damaged lithium ion cell continues to function and to deliver energy safely! The improvements in safety can be dramatic and include the ability for a cell to survive a nail penetration test and continue to function, delivering effective operating voltage for many weeks after the test. This was validated by tests carried out by NASA. The Soteria metallized film current collector is made by vapor depositing metal on a thin polymer film. Compared to metal foil current collectors, significantly less metal is required, which leads to reduced weight and lower cost. Batteries made with these current collectors show good cycle life, rate capability up to 2C and improved energy density. Soteria's go-to-market strategy is using an open innovation/consortium model. The technologies will be licensed to the highest-quality material producers worldwide to generate a robust global supply chain, which eliminates single sourcing issues and ensures geographical availability.