| abstract |
(57) [Summary] [PROBLEMS] To provide a sheet-shaped lithium secondary battery having improved blistering characteristics (bulge characteristics) when left at high temperature. SOLUTION: A solid electrolyte layer which is a porous body mainly composed of a salt, a compatible solvent, and a fluoropolymer having vinylidene fluoride as a main unit is interposed between a positive electrode and a negative electrode, It is packaged with a sheet-like package, and the salt is LiClO 4 , LiBF 4 , LiPF 6 , LiAsF 6 , L iCF 3 SO 3 , LiAlCl 4 and Li (CF 3 S At least one compound selected from O 2 ) 2 N; A sheet-type lithium secondary battery in which the compatible solvent is a mixed solvent of ethylene carbonate, propylene carbonate, diethyl carbonate, and ethyl methyl carbonate. |