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Method of making a multi-electrode double layer capacitor having single electrolyte seal and aluminum-impregnated carbon cloth electrodes

United States Patent

September 17, 2002
View the Complete Patent at the US Patent & Trademark Office
A single cell, multi-electrode high performance double layer capacitor includes first and second flat stacks of electrodes adapted to be housed in a closeable two-part capacitor case which includes only a single electrolyte seal. Each electrode stack has a plurality of electrodes connected in parallel, with the electrodes of one stack being interleaved with the electrodes of the other stack to form an interleaved stack, and with the electrodes of each stack being electrically connected to respective capacitor terminals. A porous separator is positioned against the electrodes of one stack before interleaving to prevent electrical shorts between the electrodes. The electrodes are made by folding a compressible, low resistance, aluminum-impregnated carbon cloth, made from activated carbon fibers, around a current collector foil, with a tab of the foils of each electrode of each stack being connected in parallel and connected to the respective capacitor terminal. The height of the interleaved stack is somewhat greater than the inside height of the closed capacitor case, thereby requiring compression of the interleaved electrode stack when placed inside of the case, and thereby maintaining the interleaved electrode stack under modest constant pressure. The closed capacitor case is filled with an electrolytic solution and sealed. A preferred electrolytic solution is made by dissolving an appropriate salt into acetonitrile (CH.sub.3 CN). In one embodiment, the two parts of the capacitor case are conductive and function as the capacitor terminals.
Farahmandi; C. Joseph (San Diego, CA), Dispennette; John M. (Oceanside, CA), Blank; Edward (San Diego, CA), Kolb; Alan C. (Rancho Santa Fe, CA)
Maxwell Electronic Components Group, Inc. (San Diego, CA)
09/ 573,443
May 16, 2000
The invention described herein may be subject to limited Government rights and licenses pursuant to the Government Waiver of Invention Rights under Department of Energy (DOE) SubContract EGG-C91-103647.