Device case and method of manufacturing the same

A device case, comprising:

• a case body comprising a side wall and an opening;
• a lid pate for dosing the opening, an end portion of the lid plate being projected horizontally from an outer surface of the side wall;
• and
• a welded portion that joins the lid plate with the side wall,
• a power generating element disposed within the device case,
• wherein the lid plate comprises a beam receiving area located in a vicinity of the end portion of the lid plate configured for receiving a beam emitted vertically with respect to the beam receiving area, wherein the beam receiving area extends on a top surface of the lid plate in a direction that the end portion of the lid plate projects from the outer surface of the side wall,
• wherein the welded portion extends over the end portion of the lid plate, extends to the top surface of the lid plate, and does not reach an inner surface of the side wall,
• wherein a thickness of the welded portion in a thickness direction of the lid plate is more than a thickness of the welded portion in a thickness direction of the side wall, and
• wherein, in the thickness direction of the side wall, the welded portion bulges beyond the outer surface of the side wall, and in the thickness direction of the lid plate, the welded portion reaches the top surface of the lid plate.