A battery connector comprises an insulative housing comprising mounting surface and a top surface opposite to the mounting surface. A receiving chamber is defined in the housing from the top surface with first and second conductive terminals spatially arranged within the chamber. The chamber features at least a rounded corner for conforming to a rounded edge of a battery to be inserted so as to prevent the battery from being inserted incorrectly. The rounded corner has a curve surface tangent to two inner side walls of the chamber.