An energy storage device, characterized in that, comprising: an energy storage unit comprising a top wall and a side wall connected to a periphery of the top wall; and a protection assembly disposed to cover the top wall, wherein the protection assembly comprises a protection plate and a guide plate connected to a periphery of the protection plate, wherein the protection plate and the guide plate are connected at a predetermined angle, the protection plate is disposed corresponding to the top wall to form an air flow passage between the protection plate and the top wall, at least a portion of the guide plate and the side wall are spaced apart to form a guide chamber between the guide plate and the side wall, and the air flow passage is in communication with the guide chamber, the protection plate comprises an air flow recess disposed corresponding to the energy storage unit, wherein the air flow recess is formed by the protection plate protruding away from the energy storage unit, the energy storage unit is a secondary battery, which comprises a top cover and a housing connected to a periphery of the top cover, wherein the top wall is a top surface of the top cover, and the side wall is a side surface of the housing, and the energy storage device is a battery pack which comprises a case having an opening, and a plurality of the secondary batteries are located in the case, wherein the battery pack further comprises a cover disposed at the opening, and the protection assembly is disposed between the cover and the secondary batteries; or the energy storage unit is a battery module which comprises a plurality of secondary batteries disposed side by side, wherein the secondary battery comprises a top cover and a housing connected to a periphery of the top cover, the top wall is a top surface of the top cover, and the side wall is a side surface of the housing, and the energy storage device is a battery pack which comprises a case having an opening, and a plurality of the battery modules are located in the case, wherein the battery pack further comprises a cover disposed at the opening, and the protection assembly is disposed between the cover and the battery modules, the top cover of the secondary battery comprises a vent, the air flow recess comprises a first region and a second region located at a periphery of the first region, the first region is disposed corresponding to the vent, and the first region has a thickness larger than that of the second region. an energy storage unit comprising a top wall and a side wall connected to a periphery of the top wall; and a protection assembly disposed to cover the top wall, wherein the protection assembly comprises a protection plate and a guide plate connected to a periphery of the protection plate, wherein the protection plate and the guide plate are connected at a predetermined angle, the protection plate is disposed corresponding to the top wall to form an air flow passage between the protection plate and the top wall, at least a portion of the guide plate and the side wall are spaced apart to form a guide chamber between the guide plate and the side wall, and the air flow passage is in communication with the guide chamber, the protection plate comprises an air flow recess disposed corresponding to the energy storage unit, wherein the air flow recess is formed by the protection plate protruding away from the energy storage unit, the energy storage unit is a secondary battery, which comprises a top cover and a housing connected to a periphery of the top cover, wherein the top wall is a top surface of the top cover, and the side wall is a side surface of the housing, and the energy storage device is a battery pack which comprises a case having an opening, and a plurality of the secondary batteries are located in the case, wherein the battery pack further comprises a cover disposed at the opening, and the protection assembly is disposed between the cover and the secondary batteries; or the energy storage unit is a battery module which comprises a plurality of secondary batteries disposed side by side, wherein the secondary battery comprises a top cover and a housing connected to a periphery of the top cover, the top wall is a top surface of the top cover, and the side wall is a side surface of the housing, and the energy storage device is a battery pack which comprises a case having an opening, and a plurality of the battery modules are located in the case, wherein the battery pack further comprises a cover disposed at the opening, and the protection assembly is disposed between the cover and the battery modules, the top cover of the secondary battery comprises a vent, the air flow recess comprises a first region and a second region located at a periphery of the first region, the first region is disposed corresponding to the vent, and the first region has a thickness larger than that of the second region.