A capacitor assembly that is stable under extreme conditions is provided. A capacitor assembly that is capable of achieving a high capacitance and yet remain thermally and mechanically stable under extreme conditions. Even at high capacitance values, good mechanical stability can be achieved by connecting multiple individual capacitor elements to the housing of the assembly. Without intending to be limited by theory, it is believed that the use of multiple elements increases the surface area over which the elements are connected to the housing. Among other things, this allows the elements to dissipate vibrational forces incurred during use over a larger area, which reduces the likelihood of delamination. The capacitor elements are also enclosed and hermetically sealed within a single housing in the presence of a gaseous atmosphere that contains an inert gas, thereby limiting the amount of oxygen and moisture supplied to the solid electrolyte of the capacitor elements. Through the combination of the features noted above, the capacitor assembly is able to better function under extreme conditions.