A battery module according to the present invention includes rechargeable batteries that include a first terminal and a second terminal which protrude outward, the first terminal including differentiation portions formed of an indentation or a protruding portion to differentiate the first terminal from the second terminal; and connection members that electrically connect the rechargeable batteries, fixed to the first and second terminals of adjacent rechargeable batteries, including verification portions which fit the differentiation portions so as to improve assemblability and minimize contact resistance.