POWER SUPPLY DEVICE, ELECTRIC VEHICLE COMPRISING POWER SUPPLY DEVICE, AND POWER STORAGE DEVICE

A power supply device includes: battery block formed by stacking a plurality of battery cells in a thickness with separator interposed therebetween; a pair of end plates disposed on both end surfaces of battery block; and binding bar that is coupled to the pair of end plates and fixes battery block in a pressurized state via end plates. Separator is an elastomer, and both surfaces of plate-shaped part are formed into uneven layers having different amounts of change in thickness with respect to a pressing force.