A battery container of an electric vehicle is installed on the battery container supporting stand of the electric vehicle body. The container is a composite type and formed through alignment and combination of first and second cases. There are connecting ports, mutually embedded and mounted, on the assembled sides of these cases. The connecting ports have positive and negative electric connectors that can be oppositely inserted and jointed. The electrodes of the batteries inside the two cases can be connected. The battery container supporting stand forms a shape of a supporting surface. To ensure that the cases are placed together on the battery container supporting stand after alignment and combination, the assemblies of the positioning structure are used to control the positioning of and detachment between the battery container supporting stand and the cases. The battery container of an electric vehicle can be easily detached for independent charge.