TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Module: In the battery module above, each of the first and second terminals (140, 240, 330, 430, 530, 630; 130, 230, 340, 440, 540, 640) has a plate shape. Each of the rechargeable batteries (100, 200, 300, 400, 500, 600) comprises: an electrode assembly (110) comprising a positive electrode (111), a negative electrode (112), and a separator (113) between the positive electrode (111) and the negative electrode (112); a case (150, 250, 350, 450, 550) containing the electrode assembly (110); a cap plate (120, 220, 320, 420, 520) coupled to an opening of the case (150, 250, 350, 50, 550); and a rivet (121, 221, 321, 421, 521, 621) fixing the first terminal (140, 240, 330, 430, 530, 630) or the second terminal (130, 230, 340, 440, 540, 640) to the cap plate (120, 220,320,420,520). Each of the rechargeable batteries (100, 200, 300, 400, 500, 600) further comprises a lead member (128) electrically connecting the first terminal (140, 240, 330, 430, 530, 630) or the second terminal (130, 230, 340, 440, 540, 640) to the electrode assembly (110), and a rivet (121, 221, 321, 421, 521, 621) fixing the lead member (128) to a cap plate (120, 220, 320, 420, 520) of the rechargeable batteries together with the first terminal (140, 240, 330, 430, 530, 630) or the second terminal (130, 230, 340, 440, 540, 640). The first terminal (430, 530) includes the differentiation portion (435, 535) and no indentations or protruding portions are at the second terminal (440, 540). Each of the connection members (160) has at least one contact protrusion (164) at a surface facing the first terminal (140) or the second terminal (130), and the connection member (160) is joined to the first terminal (140) or the second terminal (130) at the contact protrusion (164) by welding. The first terminal (140) has a differentiation portion comprising a first indentation (141), the second terminal (130) has a second indentation (131), and the first indentation (141) has a position or a shape at the first terminal (140) different from a position or a shape of the second indentation (131) at the second terminal (130); the first terminal (240) has a differentation portion comprising a first protruding portion (245), the second terminal (230) has a second protruding portion (235), and the first protruding portion (245) has a position or a shape at the first terminal (240) different from a position or a shape of the second protruding portion (235) at the second terminal (230); the first terminal (140) has a differentiation portion comprising a protruding portion (145), the second terminal (130) has an indentation (131), and the verification portions (162, 163) fit the protruding portion (145) and the indentation (131); or the first terminal (630) has differentiation portions comprising first protruding portions (635), the second terminal (640) has second protruding portions (645), and a distance between the first protruding portions (635) is different from a distance between the second protruding portions (645). Each of the connection members (360, 460) has indication portions (363, 364, 467) that indicate positions or shapes of the verification portions at a surface opposite to a surface where the verification portions are located. The indication portions (363, 364, 467) are selected from a protrusion, a groove, a pattern, a symbol, and a character, and/or the indication portions (363, 364) have the same shape as the differentiation portions. One of the connection members (360) is fixed by welding to the first terminal (330) of the first one of the rechargeable batteries and the second terminal (340) of the second one of the rechargeable batteries adjacent to the first one, the differentation portions comprise a first protruding portion (335) at a top of the first terminal (330) and a second protruding portion (345) at a top of the second terminal (340), the second protruding portion (345) having a shape different from the first protruding portion (335), the verification portion comprises connection grooves (364, 363) in which the first protruding portion (335) and the second protruding portion (345) fit, and the first protruding portion (335) and the verification portion (364) and the second protruding portion (345) and the verification portion (363) are joined to each other by welding. The first and second terminals (730, 740) have a plate shape, the first terminal insulating member (733) is wider than the first terminal (730), and the differentiation portion is at a top surface of the first insulating member (733). The differentiation portion is formed of a first protruding portion (733a), the second terminal insulating member (743) has a second protruding portion (743a), and the first protruding portion (733a) has a position or a shape at the first terminal insulating member (733) that is different from a position or a shape of the second protruding portion at the second terminal insulating member (743). The differentiation portion comprises at least one of a protruding portion or an indentation and no protruding portions or indentations are at the second terminal insulating member (743).