An improved process for sealing at least one ultracapacitor which includes a multi-layer structure is disclosed. The process includes the step of applying a substantial vacuum to press together an uppermost layer of the structure and a lowermost layer of the structure and to evacuate ambient gasses, wherein a sealant situated in a peripheral area between the facing surfaces of the layers forms a liquid-impermeable seal for the structure under the vacuum. In some embodiments, a press is used to apply pressure to the peripheral area on which the sealant is disposed. Usually, the ultracapacitor would be situated within an enclosable region of the press, and a collapsible membrane would be fastened over the ultracapacitor to fully enclose the region and transmit the vacuum force to the multi-layer structure. The force applied by the press itself causes the sealant to flow, thereby ensuring a complete seal upon curing of the sealant. This process can be employed to seal one ultracapacitor or a stack of at least two ultracapacitors. Another embodiment of this invention is directed to an apparatus for sealing a multi-layer ultracapacitor, comprising the elements described above.
This invention was made with Government support under NREL Subcontract No. ZCB-4-13032-02 and Prime Contract No. DE-AC36-83CH10093 awarded by the Department of Energy. The Government gas certain rights in this invention.