Electroactive Polymer Separator to Protect from Overcharging in Lithium Ion Batteries(PSI 7265-240)

78277S Overcharging of lithium-ion batteries is currently compromising the lifetime of hybrid electric vehicle battery packs. This project will develop an electroactive polymer separator that will improve the ability of a lithium-ion battery to tolerate overcharging. The electroactive polymer maintains its neutral state as an insulator during typical charging and discharging. Upon overcharging, in which the potential is greater than 4.3 V, the electroactive polymer switches to a conductor and serves as a current shunt. When the cell potential returns to voltages below 4.3 V, the polymer returns to an insulator. Phase I will demonstrate that a porous electroactive composite separator will control overcharging without compromising high power performance or self-discharge. Commercial Applications and Other Benefits as described by the awardee: In addition to the hybrid electric vehicle market, this technology should improve battery packs that are used for other applications, e.g. laptop computers.