Toyo Aluminum Kabushiki Kaisha

Toshihisa Tamai

Hiroshi Tada

Hiroyuki Sakamoto

A collector for a secondary battery includes a metal foil having throughholes shaped or arranged to achieve an increased hole area ratio to improve an active material's adhesion thereto. A throughhole in the metal foil has a largest dimension of at least 1.55 mm, and the foil has a hole area ratio of at least 40%, and a thickness of at least 5 &mgr;m and at most 200 &mgr;m. The throughhole has a peripheral shape including two substantially straight sides that extend along lines intersecting with each other on their respective extensions to form an acute angle at a corner of the throughhole. To form the metal foil, a resist film with a predetermined pattern is arranged on a solid foil, and is used as a mask to etch the foil to provide the plurality of throughholes penetrating the foil.

Growing community of inventors

Osaka, Japan

Toshihisa Tamai