Abstract: A thin and wide area lithium ion secondary battery is disclosed. The lithium ion secondary battery has a container having a flange extended outwardly from a region where a terminal is located in the container, and constituted by a can and a cap having preferred shapes, respectively, wherein the flange of the can is welded at an outer surface of the flange to an outer surface of the flange of the cap by means of micro-arc welding. A cooling jig can be easily installed to the container, allowing efficient removal of problems caused by heat upon welding, resulting in allowing application of micro-arc welding thereto without generating damage of the interior or the battery caused by heat. Accordingly, more economical and stable butt welding can be performed, thereby remarkably reducing defect occurrence rates causing leakage problem of the resulting battery, and manufacturing costs of the lithium secondary battery.

Abstract: A thin and wide area lithium ion secondary battery is disclosed. The lithium ion secondary battery has a container having a flange extended outwardly from a region where a terminal is located in the container, and constituted by a can and a cap having preferred shapes, respectively, wherein the flange of the cap is welded at an outer surface of the flange to an outer surface of the flange of the cap by means of micro-arc welding. According to the present invention, a cooling jig can be easily installed to the container, allowing efficient removal of problems caused by heat upon welding, resulting in allowing application of micro-arc welding thereto without generating damage of the interior or the battery caused by heat. Accordingly, more economical and stable butt welding can be performed, thereby remarkably reducing defect occurrence rates causing leakage problem of the resulting battery, and manufacturing costs of the lithium secondary battery.

Abstract: A pocketed electrode plate for use in a ultra-slim lithium ion secondary battery, its manufacturing method and a lithium ion secondary battery using the same. The pocketed electrode plate comprises an electrode plate which has a coating layer of an electrode active material and a non-coated projection portion. The electrode active material can reversibly insert and extract lithium ions. The electrode plates further includes separating membranes which cover both sides of the electrode plate while exposing only the non-coated projection portion, and an insulating polymer having an adhesive component on both surfaces thereof. The insulating polymer film is placed adjacent to edges of the electrode plate but does not cover any portion of the electrode surface. The insulating polymer film is thermally bonded onto two separating membranes. A plurality of pocketed electrode plates may be produced by using a pressing roll.