Battery case for vehicle and method of manufacturing of battery case

A battery case for a vehicle that houses a battery, the battery case comprising:

• a bottom plate,
• a side wall, and
• supporting members that are joined to the bottom plate and that support the side wall from a case inner side, wherein
• the battery case is installed beneath a floor of a vehicle,
• the side wall has an inner panel to which the supporting members are joined by spot welding, and an outer panel that faces the inner panel from a side that is opposite from the supporting members,
• upper portions of the inner panel and the outer panel are joined together by spot welding, and lower end portions of the inner panel and the outer panel are joined to or made integral with the bottom plate,
• at a vertical direction intermediate portion of one of the inner panel or the outer panel, there is formed a bulging portion which bulges out toward another of the inner panel or the outer panel and is joined to the other of the inner panel or the outer panel by spot welding,
• closed cross-section portions are formed at the side wall at both an upper side and a lower side of the bulging portion, respectively, and
• weld points of the spot welding that join the inner panel and the outer panel are disposed at positions that do not overlap with the supporting members as seen from a direction in which the inner panel and the outer panel face one another.