Abstract: A device for assembly and disassembly is provided. The device includes a support assembly, a bearing assembly, and a latching assembly. The support assembly includes a first support member and a locking assembly, the locking assembly includes a locking driver and a locking connection structure, and the locking connection structure is configured to support a negative pressure assembly. The latching assembly includes a first connection structure, a second connection structure, and a movable connection structure, wherein the first connection structure is latched with the second connection structure through the movable connection structure. The locking connection structure is separated from the negative pressure assembly while the movable connection structure is latched with the second connection structure, or the locking connection structure is connected to the negative pressure assembly while the movable connection structure is unlatched from the second connection structure.

Abstract: The present application a model changing method and a battery tray. The model changing method includes: limiting a limited member by a pair of limiting assemblies, where each of the limiting assemblies is provided with a first limiting surface and a second limiting surface; disposing two first limiting surfaces of the pair of limiting assemblies opposite each other to form a first accommodating cavity; and disposing two second limiting surfaces of the pair of limiting assemblies opposite each other to form a second accommodating cavity, where a length of the first accommodating cavity is not equal to that of the second accommodating cavity.