An apparatus comprising a capacitor stack, including one or more substantially planar anode layers, and one or more substantially planar cathode layers. Additionally, the capacitor has a case having a first opening and a second opening, the first opening sized for passage of the capacitor stack, and a cover substantially conforming to the first opening and sealingly connected to the first opening. Also, the capacitor includes a plate substantially conforming to the second opening and sealingly connected to the second opening, the plate defining an aperture. Additionally, the capacitor includes a plug substantially conforming to the aperture in the plate, the plug sealingly connected to the plate. The capacitor stack is disposed in the case, and the terminal is in electrical connection with the case and at least one capacitor electrode.