Method for manufacturing sealed cell

A method for manufacturing a sealed cell, the method comprising the step of:

• welding a joint between an outer can and a sealing body by applying high-energy radiation, wherein
• a plurality of grooves are formed on an outer peripheral surface of the sealing body and/or a portion of an inner peripheral surface of the outer can, the portion facing the outer peripheral surface of the sealing body, the grooves being communicated with at least one of inside and outside the cell;
• and
• a groove-forming region is formed of a plurality of the grooves having widths of 70 to 600 μm and spacings of 70 to 600 μm therebetween,
• wherein the step of welding is a step of applying the high-energy radiation in such a manner that a deepest part of a melting section formed when a material of the outer can and a material of the sealing body are melted by the high-energy radiation can be located below upper ends of the grooves forming the groove-forming region.