Improved Safety in Large Format Lithium-Ion Cells and Batteries

Li-ion batteries are attractive candidates for use as power sources in military, aerospace, commercial, and vehicular applications. Outstanding properties of Li-ion include longer battery life, reduced weight and size, lower maintenance costs, higher power capacity and higher energy densities. However, there are issues with making a truly safe Li-ion battery. For this project, Yardney has approached making a safer battery by incorporating modeling and testing, and based on that moving forward towards larger cells for Navy applications. Though a goal is to make a Li-ion cell incapable of failing, reality has us accepting a cell failure, but preventing that occurrence from propagating. Improvements include materials internal to the cell to decrease the risk of an event and its magnitude upon such an occurrence, and then considering cell geometry and inter-cell separators to 1) remove that heat as rapidly to a"safe zone"as possible, and 2) to block a majority of the heat from causing a neighboring cell to also reach it"s activation energy for thermal runaway. In addition, electronics play a major role in monitoring, and in this project Yardney is incorporating some of their latest electronics to provide a hearty monitoring system, and a safer Li-ion battery.