PURPOSE: To incorporate a PTC element into a cell itself to save the connecting work of the cell in an assembled battery, interpose a protective ring in a selective position to protect the battery from an impact from the outside of the battery, and keep high safety.
CONSTITUTION: A disc PTC element 13 and a terminal plate 14 are successively arranged on the bottom of a sheathing can 1 on which a seal body 7 is mounted, and a protective ring 15 is arranged enclosing the PTC element 13 and the terminal plate 14. A thermally contractible facing cover resin tube 16 is thermally contracted to fix the PTC element 13 on the bottom of the facing can 1 while keeping a satisfactory continuing state. Consequently, the PTC element 13 can be integrated into a lithium secondary battery with an extremely simple structure.
KAWABE MASAMICHI
YAMASHITA MASATAKA
KASAHARA SHIGEO
TAKAYAMA HAJIME
TOSHIBA CORP
ASAHI CHEMICAL IND