Patent ID: 7651820

Claim:
A gel electrolyte comprising: a matrix polymer; a nonaqueous solvent; and an electrolytic solution having an electrolyte salt containing lithium dissolved in the nonaqueous solvent, the matrix polymer being swollen with the electrolytic solution, wherein: the matrix polymer comprises polyvinylidene fluoride copolymerized with at least hexafluoropropylene in an amount of 3 wt % or more and 7.5 wt % or less, the nonaqueous solvent comprises ethylene carbonate; and at least one solvent selected from the group consisting of dimethyl carbonate, ethylmethyl carbonate, diethyl carbonate, ethylpropyl carbonate, ethyl butyl carbonate and dipropyl carbonate, a content of the ethylene carbonate in the nonaqueous solvent is 15 wt % or more and 55 wt % or less, and a total content of the at least one solvent in the nonaqueous solvent is 30 wt % or more and 85 wt % or less wherein the matrix polymer comprises the polyvinylidene fluoride further copolymerized with monochlorotrifluoroethylene in an amount of 3 wt % or more and 7.5 wt % or less.