Abstract: This invention relates to a capacitor with cells of a double electric layer comprising of a case of dielectric material for accommodating a stack of capacitor cells having a double electric layer with electrolyte therein and having been compressed together in a stack, and further having at least two current collector plates connected to the stack of capacitor cells for collecting current, and; at least two current feeders connected to the at least two current collector plates for feeding current there through, at least two platens of dielectric material for insulation of said stack of capacitor cells and for providing impermeability to an electrolyte and are inert thereto, at least two strength plates having the stack of capacitor cells therebetween, and a flexible brace member connected between said at least two strength plates for retaining and holding said stack of capacitor cells in a compressed stack.