PROLONGING OF CYCLE LIFE OF ONE KILO WATT-HOUR CLASS LITHIUM ION BATTERY

摘要

A large capacity 1kWh (400Ah) class lithium ion battery industrially usable for electric power storage as well as electric vehicle energy source was fabricated by using LiCoO_2 and natural graphite as cathode and anode materials, respectively, and LiPF_6 as an electrolyte aiming for the prolongation of battery life. Our newly designed battery remains sound after 400 cycles. These improvements were achieved by adjusting the following factors; (a) increase of electrodes size and cell number, (b) increase of Cu foil thickness for anode collector, (c) longer impregnation of separators and electrodes in the electrolytes, and (d) changing the charge-discharge mode. By setting the charging terminal voltage at 4.1V, over 700 cycles is expected.