To develop battery technology for a large-sized lithium ion battery, partic
le size of electrode active material, compression of electrodes, drying con
ditions of electrodes, and electrolyte identities were examined using a coi
n-cell, and the treatment of the lower edge of electrodes, electrode size,
adhesion of electrode active material and current collector, and impregnati
on condition of electrolytes, were studied using single cells. The followin
gs are particularly important findings obtained in this study. (1) Residual
pyrrolidone caused an increase in water content, and thus, drying of elect
rodes is important in large-sized batteries. (2) Adhesion of electrode acti
ve material and current collector can be improved by either increasing the
thickness of the current collector or by using an accurate-sized frame duri
ng the compression step of electrodes. (3) Both sides of the lower edge of
the electrode were covered by precipitates of the Li dendrite during charge
-discharge of the battery, and this precipitation was greatly inhibited by
applying paste consisting of 75% natural graphite and 25% PVdF at the edge
of the anode. (4) Impregnation of electrolytes to large-sized batteries is
very difficult compared to that in small ones, since the uniform contact be
tween electrolytes and electrodes requires a longer time. (5) Sealing of th
e battery case using a viton o-ring can efficiently avoid the mixing of wat
er inside the battery and the evaporation of solvent outside the battery.