RECTANGULAR ELECTROCHEMICAL ELEMENT STORING CONTAINER

PROBLEM TO BE SOLVED: To restrain shape deformation due to pressure rise in conjunction with the chemical reaction of a power generation element by forming a plane where the wall surface on the side of each long side of an upper pipe part is flush with the wall surface on the side of the corresponding long side of a lower pipe part, and by setting the side line connecting the short side middle point of a nearly rectangular shape at its opening end to the middle point of a semicircular shape on its bottom face almost straight line. SOLUTION: An opening end 10 forms a nearly rectangular shape in which round parts 11 are formed at its corners, and a bottom face 12 forms a shape made by forming each of the short sides of the rectangular shape into a semicircular shape. A container 1 comprises an upper pipe part 13 extending downward while keeping the nearly rectangular shape of the surface of the opening end 10 as a cross section, and a lower pipe part 14 extending toward the bottom face while keeping the shape made by forming each of the short sides of the rectangular shape into the semicircular shape. The upper pipe part 13 and the lower pipe part 14 are integrally connected while continuously varying in shape through a boundary part 15. For a cross section parallel with the bottom face 12, its maximum length is nearly equal to its maximum width at any height, and all the longitudinal sections centering the center axis of the surface of the opening end 10 form a nearly rectangular shape.