An energy storage device comprises: a housing having an opening and accommodating electrolyte; an electrode assembly accommodated in the housing; a top cover covering the opening and provided with a liquid injection hole; a lower plastic member, having a through hole, wherein the lower plastic member is arranged on a side, close to the electrode assembly, of the top cover and comprises a plurality of bosses arranged at an interval in a length direction of the lower plastic member, the plurality of bosses at least comprise a first boss and a second boss, the first boss and the second boss are respectively located on two ends of the lower plastic member in the length direction of the lower plastic member, the plurality of bosses are located on a side, towards the electrode assembly, of the lower plastic member, and the through hole is in communication with the liquid injection hole; a connecting plate (120, 121, 122) arranged on the side, towards the electrode assembly, of the lower plastic member, wherein a gap is formed between at least a part of the connecting plate (120, 121, 122) and the lower plastic member in a thickness direction of the connecting plate (120, 121, 122); an insulating adhesive sheet attached to a side, towards the electrode assembly, of the connecting plate (120, 121, 122), and the insulating adhesive sheet covering the connecting plate (120, 121, 122) and the through hole; wherein a notch is respectively provided on a side, close to the connecting plate (120, 121, 122), of each of the first boss and the second boss, and the notch comprises a first arc segment, a second arc segment, a third arc segment and a fourth arc segment sequentially arranged in a width direction of the lower plastic member; the first arc segment is connected with the second arc segment, the third arc segment is connected with the fourth arc segment, the second arc segment is connected with the third arc segment, the first arc segment is closer to the through hole than the second arc segment, the fourth arc segment is closer to the through hole than the third arc segment; and the first arc segment, the second arc segment, the third arc segment and the fourth arc segment form an edge of the notch; the insulating adhesive sheet, the connecting plate (120, 121, 122) and the edge enclose to form a first flow channel for the electrolyte, and the electrolyte is injected through the liquid injection hole and flows towards the electrode assembly through the first flow channel. a housing having an opening and accommodating electrolyte; an electrode assembly accommodated in the housing; a top cover covering the opening and provided with a liquid injection hole; a lower plastic member, having a through hole, wherein the lower plastic member is arranged on a side, close to the electrode assembly, of the top cover and comprises a plurality of bosses arranged at an interval in a length direction of the lower plastic member, the plurality of bosses at least comprise a first boss and a second boss, the first boss and the second boss are respectively located on two ends of the lower plastic member in the length direction of the lower plastic member, the plurality of bosses are located on a side, towards the electrode assembly, of the lower plastic member, and the through hole is in communication with the liquid injection hole; a connecting plate (120, 121, 122) arranged on the side, towards the electrode assembly, of the lower plastic member, wherein a gap is formed between at least a part of the connecting plate (120, 121, 122) and the lower plastic member in a thickness direction of the connecting plate (120, 121, 122); an insulating adhesive sheet attached to a side, towards the electrode assembly, of the connecting plate (120, 121, 122), and the insulating adhesive sheet covering the connecting plate (120, 121, 122) and the through hole; wherein a notch is respectively provided on a side, close to the connecting plate (120, 121, 122), of each of the first boss and the second boss, and the notch comprises a first arc segment, a second arc segment, a third arc segment and a fourth arc segment sequentially arranged in a width direction of the lower plastic member; the first arc segment is connected with the second arc segment, the third arc segment is connected with the fourth arc segment, the second arc segment is connected with the third arc segment, the first arc segment is closer to the through hole than the second arc segment, the fourth arc segment is closer to the through hole than the third arc segment; and the first arc segment, the second arc segment, the third arc segment and the fourth arc segment form an edge of the notch; the insulating adhesive sheet, the connecting plate (120, 121, 122) and the edge enclose to form a first flow channel for the electrolyte, and the electrolyte is injected through the liquid injection hole and flows towards the electrode assembly through the first flow channel.