CPC H01M 4/762 (2013.01) [H01M 4/661 (2013.01); H01M 4/765 (2013.01); Y10T 428/12479 (2015.01)] | 17 Claims |
1. A long aluminum foil comprising:
in a width direction orthogonal to a longitudinal direction,
a perforated portion;
two non-perforated portions, each provided separately at both ends of the long aluminum foil in the width direction; and
a hole density decreasing portion between the perforated portion and each of the two non-perforated portions,
wherein the perforated portion has a plurality of through-holes penetrating therethrough in a thickness direction,
the two non-perforated portions do not have a through-hole,
the hole density decreasing portions have a plurality of through-holes penetrating therethrough in the thickness direction and a plurality of non-through-holes that do not penetrate, and
in the hole density decreasing portions, an opening ratio due to the through-holes gradually decreases from a perforated portion side to a non-perforated portion side.
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