Lithium secondary battery for improving bondability of tab to polymer film

摘要

A lithium secondary battery includes an electrode assembly having at least one tab which projects from one side of the electrode assembly, an external finishing material surrounding and sealing the tab except a distal end portion thereof and the electrode assembly, and polymer films interposed between the external finishing material and the tab to improve adhesion therebetween. When the tab has a thickness no less than a predetermined thickness, the tab is formed to have a sectional shape which ensures that an inside angle defined by one of upper and lower surfaces of the tab and an adjacent side surface of the tab becomes an obtuse angle, and the polymer films are formed to have protuberances on the inner surfaces thereof, so as to improve bondability between the tab and the polymer films.

主权项

1. A lithium secondary battery assembly comprising:
an electrode assembly having at least one tab which projects from a side of the electrode assembly, a pair of upper and lower polymer films respectively covering upper and lower surfaces of the tab, wherein each of the upper and lower polymer films is in direct contact with the tab, wherein the upper polymer film has a first uniform thickness and the lower polymer film has a second uniform thickness, and protuberances each extending from oppositely facing inner surfaces of the pair of upper and lower polymer films, positioned adjacent to both ends of the tab, and coupled to each other to seal the both ends of the tab, wherein the distance measured between the protuberances on each film is greater than the width of the tab.