To satisfy each of high-rate discharge, low temperature and cycle characteristics with a satisfactory balance by arranging the polymer gel of an electrolytic layer, having the polymer gel having a high molecular skeleton and a solvent and an electrically insulating separator also in a positive electrode and a negative electrode, and setting the porosities of the positive electrode and the negative electrode to a specified ratio or lower.
An electrolytic layer is formed of a polymer gel and an electrically insulating separator, and the same polymer gel as the electrolytic layer is arranged also in a positive electrode and a negative electrode. The polymer forming the polymer gel desirably contains an acrylonitrile group, a propylene oxide group, or the like. The content of the high molecular skeleton in the polymer gel is preferably 20 wt.% or less, and the solvent included therein is, for example, ethylene carbonate. The porosities of the positive electrode and the negative electrode is 2 vol.% or lower. A chemical cross-linked gel is continuously present in both the electrode and in the electrolyte, and a nonwoven fabric, for example, is desirably arranged as the separator within the electrolytic layer.
MURATA TOSHIHIDE
TAKEYAMA KENICHI
