An eco-friendly power source, such as a battery module for a transportation vehicle includes a first sub-module and a second sub-module each including a plurality of battery cells; a lower cover supporting the first sub-module and the second sub-module; a connection member coupled to the first sub-module and the second sub-module, respectively; and a cooling plate coupled to the lower cover and forming a flow path through which a refrigerant can flow, wherein at least a portion of the flow path is disposed to oppose the connection member with the lower cover interposed therebetween.