Battery module, comprising: a first battery cell arrangement structure and a second battery cell arrangement structure stacked in a vertical direction, wherein the first battery cell arrangement structure and the second battery cell arrangement structure both comprise a plurality of battery cells arranged in a horizontal direction, the battery cell comprises a first electrode terminal, a second electrode terminal and a battery housing, and the first electrode terminal and the second electrode terminal are disposed on a surface of the battery housing; and a bus bar array, wherein the bus bar array electrically connects the plurality of battery cells, the bus bar array comprises a first bus bar, one end of the first bus bar is connected to the first electrode terminal of the first battery cell arrangement structure, the other end of the first bus bar is connected to the second electrode terminal of the second battery cell arrangement structure, and the first bus bar extends in a first direction, and the first direction intersects the horizontal direction and the vertical direction; wherein the first bus bar comprises a first end portion, a transition portion and a second end portion, the first end portion is connected to the first electrode terminal, the second end portion is connected to the second electrode terminal, and the transition portion connects the first end portion and the second end portion; wherein the battery housing is provided with an explosion-proof valve, the explosion-proof valve is disposed between the first electrode terminal and the second electrode terminal, and the first bus bar is set to avoid the explosion-proof valve; and wherein the transition portion is disposed between explosion-proof valves of two battery cells stacked in the vertical direction. a first battery cell arrangement structure and a second battery cell arrangement structure stacked in a vertical direction, wherein the first battery cell arrangement structure and the second battery cell arrangement structure both comprise a plurality of battery cells arranged in a horizontal direction, the battery cell comprises a first electrode terminal, a second electrode terminal and a battery housing, and the first electrode terminal and the second electrode terminal are disposed on a surface of the battery housing; and a bus bar array, wherein the bus bar array electrically connects the plurality of battery cells, the bus bar array comprises a first bus bar, one end of the first bus bar is connected to the first electrode terminal of the first battery cell arrangement structure, the other end of the first bus bar is connected to the second electrode terminal of the second battery cell arrangement structure, and the first bus bar extends in a first direction, and the first direction intersects the horizontal direction and the vertical direction; wherein the first bus bar comprises a first end portion, a transition portion and a second end portion, the first end portion is connected to the first electrode terminal, the second end portion is connected to the second electrode terminal, and the transition portion connects the first end portion and the second end portion; wherein the battery housing is provided with an explosion-proof valve, the explosion-proof valve is disposed between the first electrode terminal and the second electrode terminal, and the first bus bar is set to avoid the explosion-proof valve; and wherein the transition portion is disposed between explosion-proof valves of two battery cells stacked in the vertical direction.