The invention relates to an energy storage device. The energy storage device comprises a battery rack and a battery box mounted in the battery rack, and the battery rack comprises a battery box mounting cavity. The energy storage device further comprises a handle mechanism, and the handle mechanism comprises a handle, a rotating shaft and an elastic reset piece, wherein the rotating shaft is provided with an axis parallel to the push-pull direction of the battery box, and the handle is provided with a stop arm, and has a stop position and an avoidance position. The elastic reset piece is usedfor applying an acting force moving towards the battery box loading direction to the handle, and the handle is further provided with a positioning part. The opening edges of the battery box and the battery box mounting cavity are provided with corresponding positioning adaptive parts. When the energy storage device is used for storing and taking the battery box, the operation is easy, and the consumed time is short. When an emergency occurs, the battery box loading and unloading path can be rapidly opened to treat the battery box, and the potential safety hazards are rapidly eliminated.