A battery module, comprising: a plurality of pouch-type secondary batteries configured to respectively have a first electrode lead and a second electrode lead and arranged to be stacked in at least one direction; and a bus bar made of an electrically conductive material and contacted to at least two of the first and second electrode leads (111, 112) of the secondary batteries to electrically connect the secondary batteries to each other, wherein the bus bar includes: at least two metal plates (221, 222) contacted and connected to at least two of the first electrode leads and the second electrode leads of at least two secondary batteries; and a main frame coupled to the metal plates (221, 222) so that the metal plates (221, 222) are at least partially exposed to the outside, wherein at least one of the metal plates (221, 222) has a different kind of metal material from the main frame, wherein the metal plates (221, 222) include: a first metal plate contacted and connected to the first electrode lead of at least one secondary battery; and a second metal plate contacted and connected to the second electrode lead of at least one secondary battery, and wherein the first metal plate is made of the same material as the first electrode lead of the secondary battery to which the first metal plate is contacted and connected, and wherein the second metal plate is made of the same material as the second electrode lead of the secondary battery to which the second metal plate is contacted and connected. a plurality of pouch-type secondary batteries configured to respectively have a first electrode lead and a second electrode lead and arranged to be stacked in at least one direction; and a bus bar made of an electrically conductive material and contacted to at least two of the first and second electrode leads (111, 112) of the secondary batteries to electrically connect the secondary batteries to each other, wherein the bus bar includes: at least two metal plates (221, 222) contacted and connected to at least two of the first electrode leads and the second electrode leads of at least two secondary batteries; and a main frame coupled to the metal plates (221, 222) so that the metal plates (221, 222) are at least partially exposed to the outside, wherein at least one of the metal plates (221, 222) has a different kind of metal material from the main frame, wherein the metal plates (221, 222) include: a first metal plate contacted and connected to the first electrode lead of at least one secondary battery; and a second metal plate contacted and connected to the second electrode lead of at least one secondary battery, and wherein the first metal plate is made of the same material as the first electrode lead of the secondary battery to which the first metal plate is contacted and connected, and wherein the second metal plate is made of the same material as the second electrode lead of the secondary battery to which the second metal plate is contacted and connected. at least two metal plates (221, 222) contacted and connected to at least two of the first electrode leads and the second electrode leads of at least two secondary batteries; and a main frame coupled to the metal plates (221, 222) so that the metal plates (221, 222) are at least partially exposed to the outside, wherein at least one of the metal plates (221, 222) has a different kind of metal material from the main frame, wherein the metal plates (221, 222) include: a first metal plate contacted and connected to the first electrode lead of at least one secondary battery; and a second metal plate contacted and connected to the second electrode lead of at least one secondary battery, and wherein the first metal plate is made of the same material as the first electrode lead of the secondary battery to which the first metal plate is contacted and connected, and wherein the second metal plate is made of the same material as the second electrode lead of the secondary battery to which the second metal plate is contacted and connected. a first metal plate contacted and connected to the first electrode lead of at least one secondary battery; and a second metal plate contacted and connected to the second electrode lead of at least one secondary battery, and wherein the first metal plate is made of the same material as the first electrode lead of the secondary battery to which the first metal plate is contacted and connected, and wherein the second metal plate is made of the same material as the second electrode lead of the secondary battery to which the second metal plate is contacted and connected.