SIDE SILL REINFORCEMENT STRUCTURE FOR ELECTRIC VEHICLE

A side sill reinforcement structure includes a battery unit for drive, a side sill extending in a vehicle front-rear direction on an outer side in a vehicle width direction of the battery unit, and a reinforcing member that connects the battery unit and the side sill. The reinforcing member includes a closed cross-sectional portion group having a first closed cross-sectional portion disposed on the innermost side in the vehicle width direction and a second closed cross-sectional portion disposed adjacent to the first closed cross-sectional portion. The first closed cross-sectional portion includes a first upper wall and a first lower wall. The second closed cross-sectional portion includes a second upper wall and a second lower wall. The thickness of the first upper wall is larger than the thickness of the second upper wall, and the thickness of the first lower wall is larger than the thickness of the second lower wall.