LITHIUM-ION SECONDARY BATTERY

摘要

A lithium-ion secondary battery where a current collecting member and a foil are joined to each other securely while damage of the foil is suppressed is provided. The lithium-ion secondary battery is provided with a winding group obtained by winding a positive electrode plate and a negative electrode plate via a separator. An end portion of a positive electrode mixture non-application portion and an end portion of a negative electrode mixture non-application portion project at an upper portion and a lower portion of the winding group, respectively. Current collecting disks 7 are disposed so as to face both end faces of the winding group, respectively. The current collecting disk 7 has projecting ridge portions 8 on a face thereof opposite to the winding group and flat face portions facing the winding group at positions corresponding to the projecting ridge portions 8. The projecting ridge portions 8 are formed radially. The end portion of the positive electrode mixture non-application portion and the end portion of the negative electrode mixture non-application portion are caused to abut on the flat face portions of the current collecting disks 7 and joining is performed by irradiating the projecting ridge portions 8 with laser beam. The flat face portions of the current collecting disks 7 abut on the end portion of the positive electrode mixture non-application portion and the end portion of the negative electrode mixture non-application portion approximately evenly.