A battery pack, comprising: a first battery module group including one or more battery modules (20a, 20b); a second battery module group including one or more battery modules (30a, 30b), the second battery module group being aligned with the first battery module group; a guide member between the first and second battery module groups (20, 30); two or more support members that support bottom surfaces of the battery modules (20a, 20b, 30a, 30b) of the first and second battery module groups (20, 30), the two or more support members being spaced apart from each other; and a housing that accommodates the first and second battery module groups (20, 30) therein, wherein the guide member is provided to a battery module of the first battery module group adjacent to the second battery module group so as to change a flow path of a heat exchange medium passing through the first battery module group; further comprising a bottom member provided at a lower portion of the battery module adjacent to the guide member, wherein a height of the bottom member corresponds to that of the support members, and further comprising at least one side member, wherein the side member is provided between an inner surface of the housing and the battery module of the second battery module group adjacent to the first battery module group, characterized by a first main heat exchange flow path (S1a) that passes through the first battery module group; a first sub-heat exchange flow path (S1b) that passes between the neighboring support members at a lower portion of the first battery module group; a first convergence heat exchange flow path that passes between neighboring support members at a lower portion of the second battery module group; one or more second heat exchange flow paths that pass between an outer surface of the first battery module group and an inner surface of the housing; and a second convergence heat exchange flow path that passes through the second battery module group, wherein: the first main heat exchange flow path (S1a) and the first sub-heat exchange flow path (S1b) combine to form a first heat exchange flow path such that the first heat exchange flow path is connected to the first convergence heat exchange flow path by the guide member, and the one or more second heat exchange flow paths combine to form the second convergence heat exchange flow path at a rear stage of the guide member. a first battery module group including one or more battery modules (20a, 20b); a second battery module group including one or more battery modules (30a, 30b), the second battery module group being aligned with the first battery module group; a guide member between the first and second battery module groups (20, 30); two or more support members that support bottom surfaces of the battery modules (20a, 20b, 30a, 30b) of the first and second battery module groups (20, 30), the two or more support members being spaced apart from each other; and a housing that accommodates the first and second battery module groups (20, 30) therein, wherein the guide member is provided to a battery module of the first battery module group adjacent to the second battery module group so as to change a flow path of a heat exchange medium passing through the first battery module group; further comprising a bottom member provided at a lower portion of the battery module adjacent to the guide member, wherein a height of the bottom member corresponds to that of the support members, and further comprising at least one side member, wherein the side member is provided between an inner surface of the housing and the battery module of the second battery module group adjacent to the first battery module group, characterized by a first main heat exchange flow path (S1a) that passes through the first battery module group; a first sub-heat exchange flow path (S1b) that passes between the neighboring support members at a lower portion of the first battery module group; a first convergence heat exchange flow path that passes between neighboring support members at a lower portion of the second battery module group; one or more second heat exchange flow paths that pass between an outer surface of the first battery module group and an inner surface of the housing; and a second convergence heat exchange flow path that passes through the second battery module group, wherein: the first main heat exchange flow path (S1a) and the first sub-heat exchange flow path (S1b) combine to form a first heat exchange flow path such that the first heat exchange flow path is connected to the first convergence heat exchange flow path by the guide member, and the one or more second heat exchange flow paths combine to form the second convergence heat exchange flow path at a rear stage of the guide member. the first main heat exchange flow path (S1a) and the first sub-heat exchange flow path (S1b) combine to form a first heat exchange flow path such that the first heat exchange flow path is connected to the first convergence heat exchange flow path by the guide member, and the one or more second heat exchange flow paths combine to form the second convergence heat exchange flow path at a rear stage of the guide member.