Patent ID: 7273503

Claim:
A method for manufacturing the lithium polymer secondary battery comprising the steps of: providing an anode having an electroactive substance comprised of a carbonaceous material capable of electrochemically inclusion and release of lithium and a cathode having an electroactive substance comprised of a chalcogenide compound containing lithium; forming a polymer electrolyte layer comprised of a matrix of ion-conductive polymer retaining a nonaqueous electrolyte solution therein on the cathode and the anode, wherein said step of forming the polymer electrolyte layer comprises polymerizing and crosslinking a precursor monomer of said ion-conductive polymer in said nonaqueous solution containing a lithium salt in situ in the presence of a polymerization initiator; joining the cathode and the anode together with their polymer electrolyte layers facing inwardly to manufacture the battery; and subjecting the battery as manufactured to a heat treatment before charging the battery initially, whereby the amounts of the precursor monomer of said ion-conductive polymer and the polymerization initiator thereof remaining in said polymer electrolyte layers are decreased at least 40% after said heat treatment, wherein said heat treatment is carried out at a temperature between 40° C. and 60° C.