Electric vehicle battery case to floor attachment structure

A battery case comprising:

• a floor panel of a vehicle, which forms a floor of a body of the vehicle and an upper panel of a battery case;
• a side sill positioned at opposite sides of the floor panel, extending in a longitudinal direction of the vehicle, and extending downwardly from the floor panel in a height direction of the vehicle;
• and
• front and rear barriers extending downwardly from a front portion and a rear portion of the floor panel connected to the side sill to form a sidewall portion of the battery case together with the side sill by being connected to the side sill,
• wherein an upper cross member is formed on a top surface of the floor panel to extend in a width direction of the vehicle and protrude upwardly, and
• wherein a rear cross member extending upwardly is formed in the rear portion of the floor panel, and a plurality of rear upper side members extending in the longitudinal direction of the vehicle to connect the rear cross member to the upper cross member are formed on a top surface of the floor panel, wherein the plurality of rear upper side members are spaced apart from each other.