One embodiment of the present subject matter includes a capacitor, comprising a first metallic cupped shell having a first opening, and a second metallic cupped shell having a second opening, wherein the first opening and the second opening are adapted to sealably mate to form a closed shell defining a volume therein. In the embodiment, the closed shell is adapted for retaining electrolyte. A plurality of capacitor layers in a substantially flat arrangement are disposed within the volume, along with electrolyte, in the present embodiment. The present closed shell includes one or more ports for electrical connections.