A battery module comprising: a first cooling plate (P1) configured for supporting a first group of battery packs (M1) and in which a first cooling tube (C1) is embedded; a second cooling plate (P2) configured for supporting a second group of battery packs (M2) and in which a second cooling tube (C2) is embedded; and a third cooling plate (P3) configured for supporting a third group of battery packs (M3) and in which a third cooling tube (C3) is embedded, wherein the second cooling plate (P2) is placed at a second level (h2) higher than a first level (h1) of the first cooling plate (P1) forming a bottom of the battery module, wherein legs L are provided on the second cooling plate (P2) to support the second cooling plate (P2) above the first cooling plate (P1) with a first pack accommodation region (g1) therebetween; and wherein the first cooling plate (P1) as a whole has a T-shape with a length part (PZ1) extending in a first direction (Z1) and a width part (PZ2) extending in a second direction (Z2) perpendicular to the first direction (Z1), wherein the second cooling plate (P2) is positioned above and extends in parallel with the length part (PZ1) of the first cooling plate (P1), wherein the third cooling plate (P3) is positioned above and extends in parallel with the width part (PZ2) of the first cooling plate (P1), wherein legs L are provided on the third cooling plate (P3) to support the third cooling plate (P3) above the first cooling plate (P1) with a second pack accommodation region (g2) therebetween, wherein each of the first to third cooling tubes (C1, C2, C3) includes a plurality of tubes configured for transporting a cooling medium, wherein the plurality of tubes of the first cooling tube comprises a passage (C11) passing through a rear branch part (D2) and connected to the third cooling tube (C3) and a bypass passage (C12) bypassing the rear branch part (D2) and having a diameter smaller than a diameter of the passage (C11) connected to the third cooling tube (C3). a first cooling plate (P1) configured for supporting a first group of battery packs (M1) and in which a first cooling tube (C1) is embedded; a second cooling plate (P2) configured for supporting a second group of battery packs (M2) and in which a second cooling tube (C2) is embedded; and a third cooling plate (P3) configured for supporting a third group of battery packs (M3) and in which a third cooling tube (C3) is embedded, wherein the second cooling plate (P2) is placed at a second level (h2) higher than a first level (h1) of the first cooling plate (P1) forming a bottom of the battery module, wherein legs L are provided on the second cooling plate (P2) to support the second cooling plate (P2) above the first cooling plate (P1) with a first pack accommodation region (g1) therebetween; and wherein the first cooling plate (P1) as a whole has a T-shape with a length part (PZ1) extending in a first direction (Z1) and a width part (PZ2) extending in a second direction (Z2) perpendicular to the first direction (Z1), wherein the second cooling plate (P2) is positioned above and extends in parallel with the length part (PZ1) of the first cooling plate (P1), wherein the third cooling plate (P3) is positioned above and extends in parallel with the width part (PZ2) of the first cooling plate (P1), wherein legs L are provided on the third cooling plate (P3) to support the third cooling plate (P3) above the first cooling plate (P1) with a second pack accommodation region (g2) therebetween, wherein each of the first to third cooling tubes (C1, C2, C3) includes a plurality of tubes configured for transporting a cooling medium, wherein the plurality of tubes of the first cooling tube comprises a passage (C11) passing through a rear branch part (D2) and connected to the third cooling tube (C3) and a bypass passage (C12) bypassing the rear branch part (D2) and having a diameter smaller than a diameter of the passage (C11) connected to the third cooling tube (C3). <EOS>