The utility model relates to a flexible spacer sleeve, fixing structures utilizing the flexible spacer sleeve and a battery box utilizing the fixing structures. A connecting screw can pass through an installation through hole arranged on a box body of the battery box to match with a threaded hole disposed on a battery module in a screwing mode. A blocking edge in blocking match with the head of the connecting screw is arranged at the external end of the installation through hole, so that the battery module is prevented from moving in the radial direction of the connecting screw or in a direction away from the connecting screw. The fixing structures are arranged on at least two lateral sides of the box body, so that the battery module is prevented from moving in a direction close to the connecting screw by tensioning the battery module through the connecting screws of the two fixing structures. The flexible spacer sleeve which is arranged between the circumference of the connecting screw and the hole wall of the installation through hole can prevent the connecting screw from directly contacting with the hole wall of the installation through hole, so that installation errors between the box body and the battery module can be flexibly compensated, and the battery module can not move along the radial direction or axial direction of the connecting screw in the battery box.