Abstract: Power source device includes: battery stack in which a plurality of battery cells are stacked; a pair of end plates that each have a plate shape having a main surface and a side surface intersecting the main surface, are formed with plate screw hole on the side surface, and are arranged on both side end surfaces of battery stack; a plurality of fastening members that are extended in stack direction of the battery stack, have fastening screw holes opened at ends, and couple end plates to each other; and bolt that is inserted into fastening screw hole of each fastening member and plate screw hole of end plate to fix the fastening member to end plate. The fastening member includes plate-shaped fastening body, intermediate part obtained by bending both ends of fastening body, and coupling piece obtained by bending an end of intermediate part far from fastening body to provide a height difference from fastening body and form fastening screw hole.

Abstract: Power supply device (100) includes: battery stack (10) in which a plurality of battery cells (1) are stacked, each battery cell (1) having gas discharge valve (1c) that opens when an internal pressure of an outer covering can rises and electrode terminal (2) formed on an upper surface; first cover (41) that is provided on an upper surface of battery stack (10) and opens at a position corresponding to gas discharge valve (1c); and second cover (42) that is provided on an upper surface of first cover (41) and defines gas duct (38) with first cover (41). Gas duct (38) forms baffle plate (48) between first cover (41) and second cover (42). Power supply device (100) further includes metallic third cover (39) provided on an upper surface of second cover (42) and abutting on the upper surface of second cover (42).