Development of Separators for Lithium-Ion Cells with High Temperature Melt Integrity

Although the lithium-ion battery is the technology of choice for small-format devices such as cellular phones and notebook computers, its safety and performance shortfalls have prevented its introduction into large format systems such as hybrid electric vehicles (HEV) and plug-in hybrid electric vehicles (P-HEV). One of the concerns associated with the use of lithium-ion batteries in HEVs and PHEVs is the possibility of an internal short-circuit caused by the shrinkage of the separator at high temperatures. This project will develop a stable thermal separator for making lithium-ion batteries. The separator (1) will retain its integrity and stability at temperatures of 200 degrees C or higher; (2) will meet all of the requirements for use as a separator for lithium-ion batteries, including thickness, porosity, and cost; (3) be bondable to electrodes and give an excellent interface between separator and electrodes; and (4) have a lower thermal shut-down temperature as well as sustained thermal shut¬down at high temperatures. Commercial Applications and other Benefits as described by the awardee: The novel battery separator could be used to make batteries that will offer improved safety and reliability. In addition to their use in HEVs and P-HEVs, the batteries could be used in standby power stations.