FABRICATION AND PERFORMANCE CHARACTERISTICS OF PLASTIC Li-ION BATTERIES WITH BONDED UNTREATED MICROPOROUS POLYOLEFIN SEPARATORS

摘要

A new, simplified and reliable process for the fabrication of flat, rechargeable Li-ion batteries is reported. Densified, propylene carbonate-plasticized electrodes were permanently bonded to several different untreated microporous polyolefin separators (MPSs). The process was demonstrated using various PVDF polymers or copolymers as electrode binders and several electroactive materials. Batteries fabricated using the new technique exhibit excellent cycle life (less than 20 % capacity loss after 1000 cycles), high rate capability (75-80 % capacity utilization at a 3C rate at 3.2 mAh/cm~2), good rate capability at low temperatures (50 % capacity at -20℃at a C/2 rate), very low internal impedance (20 mohm/Ah at 1 kHz), high specific energy (>180 Wh/kg), excellent stability during storage and cycling at elevated temperatures. Importantly, the desirable thermal-shutdown behavior of the bonded separators at ca. 135℃ was not adversely affected by the process.