SECONDARY BATTERY

A secondary battery is provided and includes a battery device, a container, and a cover part. The container contains the battery device. The container includes a first end part including a crimp part, and a second end part positioned on an opposite side to the first end part in a first direction. The cover part is attached to the crimp part with a gasket interposed therebetween. The cover part includes a cover member including a first flange, and a valve member including a second flange. The second flange is opposed to the first flange in the first direction. The first and second flanges are welded to each other to configure a stacked part. The stacked part is sandwiched in the first direction by the crimp part with the gasket interposed therebetween. The stacked part includes a welding mark provided in the first direction across an interface between the first and second flanges.