Structure for electrode terminals of battery module

On the opposite end walls (8) of a flat, primatic battery case (2) of a battery module (1) where electrode terminals (12) are attached, protruding components (26) are formed such as to protrude further than the electrode terminals. Terminal holes (10) are formed in the end walls in which the electrode terminals are fitted, and the thickness of the end walls of the integral battery case in the vicinity of the terminal holes is not the same on both sides of each of the terminal holes. Also, each of the electrode terminals has a mounting structure comprising a disk-shaped seat (12a) from one surface of which the electrode terminal protrudes, a connecting protrusion (24) protruding from an opposite surface of the electrode terminal, an annular groove (40a) formed around and coaxial with said connecting protrusion, and an annular protrusion (40) around and coaxial with said annular groove. The engagement tabs (38) are formed extending radially and centred around the connecting protrusion. The engagement grooves (37) and the circular recess are connected and coplanar. The engagement tabs (38) and the annular protrusion (40) are connected and coplanar.