Designs and methods of construction for an implantable medical device employ an internal support structure. The single-piece support structure holds various electronic components such as a communication coil and a circuit board, and further is affixed to a battery, thus providing a subassembly that is mechanically robust. The support structure further provides electrical isolation between these and other components. A method of construction allows for the subassembly to be adhered to a case of the implantable medical device at the battery, and possibly also at the support structure. The battery includes an insulating cover having holes. An adhesive is used consistent with the location of the holes to affix the battery to the case without electrically shorting the battery to the case.