Work vehicle with a power-travel drive unit

1. A work vehicle comprising:

a vehicle frame;

a driving portion in which a driver seat is provided;

an electric motor for driving the vehicle to travel; and

a battery for supplying electric power to the electric motor, the battery including a plurality of battery modules accommodated in a single battery pack;

wherein each of the battery modules is formed as a rectangular box whose longitudinal length is different from its lateral length in a planar view, and the battery modules are arranged adjacent to each other with a short side of one of the battery modules opposing a long side of another of the battery modules,

wherein the battery pack is formed to conform to a contour of an aggregate of the battery modules that are accommodated, and

wherein in the battery pack, one of the battery modules and the other of the battery modules are arranged in a stepwise manner with one of the battery modules higher than the other.

2. The work vehicle according to claim 1 , wherein

in the battery pack, the one battery module, which is a laterally long battery module whose long sides extend in a lateral direction, and the other battery module, which is a longitudinally long battery module whose long sides extend in a longitudinal direction, are accommodated such that a short side of the laterally long battery module opposes a long side of the longitudinally long battery module, and

the battery pack is disposed between a left and right pair of main frames that constitutes the vehicle frame.

3. The work vehicle according to claim 1 , wherein the driver seat is provided in an intermediate position in the traveling body in the longitudinal direction, and the battery pack is disposed in a space under the driver seat.

4. The work vehicle according to claim 1 , wherein the electric motor for driving the vehicle to travel is disposed below a portion of the battery pack where the higher one of the battery modules is disposed.