SQUARE SECONDARY BATTERY

PROBLEM TO BE SOLVED: To provide a square secondary battery which can prevent separation of an insulation material covering a battery container of the square secondary battery, and improve reliability of insulation to external environment of the battery container.SOLUTION: A square secondary battery 100 with a square battery container 10 comprises: an insulating stretch film 1 having an aperture 1a at one end which covers the battery container 10 while a part of the battery container 10 is exposed from the aperture 1a; and an insulating self-adhesive film 2 which covers the battery container 10 exposed from the aperture 1a of the stretch film 1 and covers a marginal part 1b of the aperture 1a. The battery container 10 comprises: a battery can 11 with one opened end which accommodates an electrode group 40; and a battery lid 12 which includes positive electrode and negative electrode external terminals 20 and encapsulates the battery can 11. The stretch film 1 exposes at least one part of the battery lid 12 from the aperture 1a, and the self-adhesive film 2 covers the battery lid 12 exposed from the aperture 1a and includes a through hole 2a exposing the external terminals 20.SELECTED DRAWING: Figure 1A 【課題】角形二次電池の電池容器を覆う絶縁材料の剥がれを防止し、電池容器の外部環境に対する絶縁の信頼性を向上させることができる角形二次電池を提供する。【解決手段】角形の電池容器１０を備えた角形二次電池１００であって、一端に開口１ａを有し開口１ａから電池容器１０の一部を露出させた状態で電池容器１０を覆う絶縁性の伸縮フィルム１と、伸縮フィルム１の開口１ａから露出した電池容器１０を覆うとともに開口１ａの縁部１ｂを覆う絶縁性の粘着フィルム２と、を備える角形二次電池１００である。電池容器１０は、電極群４０を収容する一端が開放された電池缶１１と、正極及び負極外部端子２０が設けられ電池缶１１を封止する電池蓋１２とを有する。伸縮フィルム１は、開口１ａから電池蓋１２の少なくとも一部を露出させ、粘着フィルム２は、開口１ａから露出した電池蓋１２を覆うとともに外部端子２０を露出させる貫通孔２ａを有する。【選択図】図１Ａ