POWER STORAGE DEVICE

PROBLEM TO BE SOLVED: To inhibit strength of a welded part from being reduced.SOLUTION: A secondary battery 10 comprises a battery case 11, and an electrode assembly is housed in the battery case 11. The battery case 11 includes a bottomed square cylindrical case body 13 and a rectangular plate-shaped lid body 14. The lid body 14 includes: a top plate part 31 for closing an opening of the case body 13; and a rib 33 having a shape which protrudes from an inner surface 14b of an outer peripheral part of the top plate part 31 to the same direction as a protrusion 32. The rib 33 includes a first reinforcement part 34 having the shape which protrudes from the top plate part 31 to a bottom side wall along an outer surface 22a of a long side wall 22.SELECTED DRAWING: Figure 2 【課題】溶接部の強度の低下を抑制すること。【解決手段】二次電池１０は、電池ケース１１を備え、電池ケース１１には電極組立体が収容されている。電池ケース１１は、有底四角筒状のケース本体１３と、矩形板状の蓋体１４とを備える。蓋体１４は、ケース本体１３の開口部を閉塞する天板部３１と、天板部３１の外周部の内面１４ｂから突出部３２と同一方向に突出した形状のリブ３３を備える。リブ３３は、天板部３１から長側壁２２の外面２２ａに沿って底壁側へ突出した形状の第１補強部３４を備える。【選択図】図２