Abstract: The invention relates to a traction battery pack, comprising at least one battery pack assembly each comprising: a battery module array, which comprises a plurality of battery modules arranged in an arrangement direction, each of the battery modules comprising a plurality of cells, cell heat-insulating elements being arranged between adjacent cells, and module heat-insulating elements being arranged on two sides of each of the battery modules in the arrangement direction; a top assembly and a bottom assembly located at the top and bottom of the plurality of battery modules, respectively; side beams arranged on two sides of the battery module array respectively in a direction perpendicular to the arrangement direction, the side beams extending substantially parallel to the arrangement direction; and a smoke discharge channel, which communicates with the outside through a valve, the valve being capable of discharging a gas in the smoke discharge channel to the outside under a set condition.