Patent ID: 8158279

Claim:
A battery unit comprising: a positive electrode plate including a positive current collector and a positive active material layer formed on at least one plane of said positive current collector; a positive electrode lead electrically connected with said positive current collector; a negative electrode plate including a negative current collector and a negative active material layer formed on at least one plane of the negative current collector; a negative electrode lead electrically connected with said negative current collector; and a separator interposed between said positive electrode plate and said negative electrode plate, including a width greater than each electrode plate, and including different widths of protruding portions which stick out on either side of the electrode plate, wherein said separator is configured to include a width of one protruding portion which sticks out on one side of the electrode plate is greater than the other protruding portion which sticks out on the other side of the electrode plate, and wherein the protruding portion having a greater width is positioned at a location corresponding to a portion of the electrode plate from which each electrode lead is drawn.