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. <EOS>