A battery module includes a plurality of secondary batteries, each of the secondary batteries having a first terminal and a second terminal comprising different metals; and a plurality of bus bars, each of the bus bars including a first connecting portion comprising a first metal and connected to the first terminal of one of the secondary batteries, and a first end portion, and a second connecting portion comprising a second metal different from the first metal and connected to the second terminal of another one of the secondary batteries adjacent to the one secondary battery, and a second end portion, wherein the first end portion is connected to the second end portion by a weld.