a battery module including a plurality of rechargeable batteries , and a connector for connecting a first terminal of one of the plurality of rechargeable batteries and including a first material to a second terminal of another one of the plurality of rechargeable batteries and including a second material , wherein the connector includes : a first portion connected to the first terminal and including the first material ; and a second portion connected to the second terminal and including the second material , and a welded portion connecting the first portion and the second portion .