A battery pack, comprising: a plurality of battery modules (100, 200, 300, 400) including at least a first unit of the two battery modules (100, 200) and a second unit of the two battery modules (300, 400); a housing surrounding the plurality of battery modules (100, 200, 300, 400), the housing including an inlet (510, 520) and an outlet for a coolant medium such that a flow of the coolant medium can be realized between the inlet and the outlet in a flow direction, wherein the battery modules (100, 200, 300, 400) are arranged in the housing such that the first unit of the battery modules (100, 200) is positioned upstream and the second unit of the battery modules (300, 400) is positioned downstream in the flow direction; one or more guide members between a battery module (300, 400) of the second unit and the interior surface of the housing, characterized in that the guide member realizing a first converging coolant flow pathway (P3a), joining a first coolant flow pathway through the battery modules of the first unit (100, 200) and the second unit (300, 400) and a second coolant flow pathway along an exterior of the battery modules (100, 200) of the first unit, wherein the battery modules (100, 200 and 300, 400, respectively) of the first unit (100, 200) and second unit (300, 400) are spaced apart from each other in the flow direction by a first predetermined distance (d1, d3), the first unit of battery modules (100, 200) is spaced apart from the second unit of battery modules (300, 400) in the flow direction by a second predetermined distance, and wherein the second predetermined distance is greater than the first predetermined distance (d1, d3). a plurality of battery modules (100, 200, 300, 400) including at least a first unit of the two battery modules (100, 200) and a second unit of the two battery modules (300, 400); a housing surrounding the plurality of battery modules (100, 200, 300, 400), the housing including an inlet (510, 520) and an outlet for a coolant medium such that a flow of the coolant medium can be realized between the inlet and the outlet in a flow direction, wherein the battery modules (100, 200, 300, 400) are arranged in the housing such that the first unit of the battery modules (100, 200) is positioned upstream and the second unit of the battery modules (300, 400) is positioned downstream in the flow direction; one or more guide members between a battery module (300, 400) of the second unit and the interior surface of the housing, characterized in that the guide member realizing a first converging coolant flow pathway (P3a), joining a first coolant flow pathway through the battery modules of the first unit (100, 200) and the second unit (300, 400) and a second coolant flow pathway along an exterior of the battery modules (100, 200) of the first unit, wherein the battery modules (100, 200 and 300, 400, respectively) of the first unit (100, 200) and second unit (300, 400) are spaced apart from each other in the flow direction by a first predetermined distance (d1, d3), the first unit of battery modules (100, 200) is spaced apart from the second unit of battery modules (300, 400) in the flow direction by a second predetermined distance, and wherein the second predetermined distance is greater than the first predetermined distance (d1, d3).