Separator core and separator roll

Abstract

A core (u1, u2) around which a nonaqueous electrolyte secondary battery separator is to be wound. A side surface of the core (u1, u2) has a depression (20). This makes it possible, in a case where cores (separator cores) are stored by being stacked while still wet after cleaning, to prevent damage to a core caused by a problem where cores stick together and an core lower in a stack falls when a core higher in the stack is removed.

Dependencies are inferred from the claim text.