BATTERY SEPARATOR, METHOD FOR MANUFACTURING BATTERY SEPARATOR, CYLINDRICAL BATTERY, AND METHOD FOR MANUFACTURING CYLINDRICAL BATTERY

PROBLEM TO BE SOLVED: To provide a cylindrical battery including an electrode body comprising a positive electrode plate and a negative electrode plate overlapped with a separator interposed therebetween to be spirally wound, in which a possibility of a short circuit caused due to the penetration of a part of the positive electrode plate through the separator is reduced.SOLUTION: A separator 23 of the present invention includes: a main separator 231 formed of a material having insulation properties; and a first auxiliary separator 232 and a second auxiliary separator 233 which are formed of a material having insulation properties and partially disposed in the main separator 231. A portion where the first auxiliary separator 232 and the second auxiliary separator 233 are disposed in the main separator 231 has a higher density than other portion and the same thickness with the other portion. 【課題】セパレータを介して正極板と負極板とが重ねられて渦巻き状に巻かれた電極体を備える円筒形電池において、正極板の一部がセパレータを貫通して短絡が生ずる虞を低減する。【解決手段】本発明のセパレータ２３は、絶縁性を有する材料からなる主セパレータ２３１と、絶縁性を有する材料からなり、主セパレータ２３１に部分的に配置された第１補助セパレータ２３２及び第２補助セパレータ２３３と、を備え、主セパレータ２３１に第１補助セパレータ２３２及び第２補助セパレータ２３３が配置された部分は、それ以外の部分より密度が高いとともに、それ以外の部分と同一の厚さである。【選択図】図４