To provide a cylindrical storage battery with safety improved through securing a gas channel even if the temperature of the battery rises abnormally.
The cylindrical storage battery is provided with a spiral-shaped electrode group having a winding core space part 10a remaining after winding cores used in forming the spiral-shaped electrode group at a center part are removed, and is characterised in that the METSUKE (weight per area) of separators 11a (12a, 13a, 14a, 15a, 16a) arranged at the winding core space part 10a is smaller than that of separators arranged at an electrode facing part. Thus, if the METSUKE of the separators arranged at the winding core space part 10a is small, the fiber volume existing there 10a can be reduced. With this, when an abnormal heat is generated before the separators are molten, it becomes hard for a gas exhaust port fitted at a sealing body to be choked, and the time needed for choking can be elongated.
KUDO YASUHIRO
Yasuo Asami
Hideo Takahashi
Yoshitaka Takeyama