Patent ID: 8308826

Claim:
A method for manufacturing a battery that includes a power generation element; a case member that accommodates the power generation element in an accommodation recess of the case member and has a bottom and a side forming an opening edge of the accommodation recess; and an opening closure member that closes the accommodation recess of the case member and has around an entire periphery thereof an annular case contact part for contacting the opening edge of the case member from an outer side, and a case inside part positioned internally of the case contact part in an extending direction of the opening closure member and projecting toward the accommodation recess of the case member relative to the case contact part, the opening edge including a first longest straight edge and a second longest straight edge that is as long as and in parallel to the first longest straight edge, the side including a first side forming the first longest straight edge and a second side forming the second longest straight edge, the side of the case member and the case contact part of the opening closure member being welded to each other around an entire periphery of the side and the case contact part, the method comprising: positioning the case inside part of the opening closure member between the first side and the second side; disposing the first side such that a first center edge of a first edge of the first side contacts the case inside part to prevent warping deformation of the first edge toward the accommodation recess and such that a first-first end and a first-second end of the first edge and the case inside part are spaced from each other, wherein the first edge is a portion of the first side that is along the first longest straight edge, the first-first end and the first-second end are both ends of the first edge in a direction along the first longest straight edge, and the first center edge is a portion of the first edge between the first-first end and the first-second end; and disposing the second side such that a second center edge of a second edge of the second side contacts the case inside part to prevent warping deformation of the second edge toward the accommodation recess and such that a second-first end and a second-second end of the second edge and the case inside part are spaced from each other, wherein the second edge is a portion of the second side that is along the second longest straight edge, the second-first end and the second-second end are both ends of the second edge in a direction along the second longest straight edge, and the second center edge is a portion of the second edge between the second-first end and the second-second end.