A battery module, comprising: a battery unit comprising a first total output electrode and a second total output electrode of opposite polarities, wherein the battery unit comprises two or more battery assemblies arranged side by side, and two adjacent battery assemblies are connected in series with each other, each of the battery assemblies comprises at least one secondary battery, and two pole posts of respective secondary batteries are arranged to form two columns of pole post groups, and there is an accommodation gap extending between the two columns of pole post groups in the arrangement direction of the secondary batteries; the first output pole piece comprising a first connection portion, an intermediate connection portion, and a first output portion connected in sequence, wherein the first connection portion is connected to the first total output electrode, and the intermediate connection portion is connected to a portion of the first connection portion on a side close to the accommodation gap; a second output pole piece comprising a second connection portion and a second output portion, wherein the second total output electrode is positioned on a side of the first total output electrode close to the second output portion, the second connection portion is connected to the second total output electrode; the first output portion and the second output portion are disposed on the same side of the battery unit, wherein the intermediate connection portion comprises a first extension section, a second extension section, and a third extension section successively distributed along the arrangement direction, and the first extension section and the third extension section are disposed to intersect with the second extension section respectively, the first extension section and the third extension section are disposed to stagger with each other, the first connection portion is connected to the first extension section, and the second extension section extends away from the second output pole piece to avoid the position of the second output pole piece, and the first output portion is connected to the third extension section. a battery unit comprising a first total output electrode and a second total output electrode of opposite polarities, wherein the battery unit comprises two or more battery assemblies arranged side by side, and two adjacent battery assemblies are connected in series with each other, each of the battery assemblies comprises at least one secondary battery, and two pole posts of respective secondary batteries are arranged to form two columns of pole post groups, and there is an accommodation gap extending between the two columns of pole post groups in the arrangement direction of the secondary batteries; the first output pole piece comprising a first connection portion, an intermediate connection portion, and a first output portion connected in sequence, wherein the first connection portion is connected to the first total output electrode, and the intermediate connection portion is connected to a portion of the first connection portion on a side close to the accommodation gap; a second output pole piece comprising a second connection portion and a second output portion, wherein the second total output electrode is positioned on a side of the first total output electrode close to the second output portion, the second connection portion is connected to the second total output electrode; the first output portion and the second output portion are disposed on the same side of the battery unit, wherein the intermediate connection portion comprises a first extension section, a second extension section, and a third extension section successively distributed along the arrangement direction, and the first extension section and the third extension section are disposed to intersect with the second extension section respectively, the first extension section and the third extension section are disposed to stagger with each other, the first connection portion is connected to the first extension section, and the second extension section extends away from the second output pole piece to avoid the position of the second output pole piece, and the first output portion is connected to the third extension section.