High Porosity Polymer Separators for High Power Lithium-ion Batteries

The porosity of Boundless' new innovative lithium-ion battery separator material is over 45% greater than that of the current state of the art, thereby allowing significantly higher power operation of lithium-ion battery cells. Test cells in Phase I showed increases in power of 28-37% relative to those with Celgardr 2500 separators. The fabrication process for the new separator is significantly simpler than that used for Celgardr and others, and could reduce the cost of the separator for lithium-ion batteries by an estimated 75 to 90%, benefiting both DOD and commercial customers. Boundless demonstrated the simplicity and cost benefits of the new technology by making and testing 147 batches of separator material within the cost and schedule constraints of the Phase I contract. Phase I research yielded an understanding of the parameters affecting separator porosity and strength used to optimize performance, and culminated in the demonstration of lower-resistance lithium-ion battery cells incorporating the new separator. Commercial collaborators will support Boundless in the Phase II effort. A coatings manufacturer will help develop pilot production processes and optimize the separator in the context of a production environment, and a commercial battery manufacturer will incorporate and test the new separator in commercial cells.