Patent ID: 7993770

Claim:
A cylindrical lithium ion secondary battery, comprising: a wound electrode assembly that includes a positive electrode plate having a positive current collector, a positive active material arranged to form a coated portion of the positive current collector and a positive electrode tab welded to an uncoated portion of the positive current collector, a negative electrode plate having a negative current collector, a negative active material arranged to form a coated portion of the negative current collector, and a negative electrode tab welded to an uncoated portion of the negative current collector, and a separator interposed between the positive electrode plate and the negative electrode plate; a case for receiving the electrode assembly; and a cap assembly for sealing a top opening of the case; wherein at least one of the positive electrode tab and the negative electrode tab includes: a projection portion extending above a remainder of the wound electrode assembly, and a center pin portion arranged on one of the positive electrode plate and the negative electrode plate and having a width greater than that of the projection portion.