NOVELTY - Vehicle battery pack housing structure comprises: (a) a vehicle body panel (1); (b) a first panel component rigidly attached to the vehicle body panel; (c) a second panel component (19) rigidly attached to the first panel component; and (d) a third panel component (20) rigidly attached to the second panel component so that the first, second, and third panel components define an outward-opening battery housing space.    USE - Used as vehicle battery pack housing structure.    ADVANTAGE - The internal volume of the battery housing space need not be reduced to limit the size and capacity of the battery pack. The battery housing space is configured as a downward-opening battery housing space in which the floor panel is recessed upward in the vertical direction of the vehicle body, unused dead space directly below the seats is effectively utilized. Thus, the battery housing space can be enlarged without sacrificing vehicle interior space, and the capacity of the battery pack can be increased.    DETAILED DESCRIPTION - Vehicle battery pack housing structure comprises: (a) a vehicle body panel (1); (b) a first panel component rigidly attached to the vehicle body panel, where the first panel component includes a first side wall and a base wall; (c) a second panel component (19) rigidly attached to the first panel component, where the second panel component includes a second side wall (14) and a first periphery wall portion (16); and (d) a third panel component (20) rigidly attached to the second panel component so that the first, second, and third panel components define an outward-opening battery housing space, where the third panel component includes a second periphery wall portion that cooperates with the first periphery wall portion to form a periphery wall portion when the third panel component is rigidly attached to the second panel component.    DESCRIPTION OF DRAWING(S) - The drawing shows a perspective view from above the left side of a vehicle battery pack housing structure.    Vehicle body panel (1)    Second side wall (14)    Periphery wall portion (16)    Second panel component (19)    Third panel component (20)