Patent ID: 7285360

Claim:
A polymer gel electrolyte composition having a semi-interpenetrating polymer network structure, and comprising a crosslinked polymer network matrix having a three-dimensional crosslinked structure containing a solution of an electrolyte in a non-aqueous solvent, and a non-crosslinked polymer penetrating the crosslinked polymer network gel matrix, the polymer gel electrolyte composition containing 1 part by weight of the crosslinked polymer, 0.1 to 2 parts by weight of the crosslinked polymer network matrix and 3 parts by weight or more of the electrolyte solution, wherein the non-crosslinked polymer is obtained by esterifying a precursor polymer containing (a) an ethylene unit and/or propylene unit and (b) an unsaturated carboxylic acid unit, with a polyalkylene glycol compound having one terminal hydroxyl group protected, conducting the esterification until an amount of unreacted carboxylic acid in the precursor polymer becomes 5% by weight or less, in terms of acrylic acid, and thereafter removing unreacted polyalkylene glycol until a content thereof in the non-crosslinked polymer becomes 10% by weight or less.