Maxwell Technologies, Inc.

Maxwell Energy Products, Inc.

Maxwell Electronic Components Group, Inc.

Maxwell Laboratories, Inc.

Edward Blank

John M Dispennette

C Joseph Farahmandi

Robert W Crawford

Chenniah Nanjundiah

Alan C Kolb

A long life double layer capacitor and method of making the same including a case and a first terminal with an electrically insulating hermitic seal interposed between the first terminal and the case. A first current collector foil is electrically coupled to an interior portion of the first terminal and a first electrode comprising carbon which is juxtaposed against the first current collector foil. A porous separator is then juxtaposed against the first electrode comprising carbon and separating the first electrode from a second electrode comprising carbon. A second current collector foil is juxtaposed against a side of the second electrode and is electrically coupled to the second terminal. And an electrolyte solution saturates the first and second electrodes comprising carbon and is substantially contained by the case and the electrically insulating hermitic seal such that an influx of impurities into the electrolyte solution is substantially inhibited by the case and the electrically insulating hermetic seal.

Method of making a multi-electrode double layer capacitor having hermetic electrolyte seal

Multi-electrode double-layer capacitor having hermetic electrolyte seal

Multi-electrode double layer capacitor having hermetic electrolyte seal

A method of making a double layer capacitor consists of the steps of: impregnating each of a plurality of carbon preforms with a metal; forming a plurality of current collector foils, each of the plurality of current collector foils having a tab portion and a paddle portion; forming a plurality of electrodes by positioning one of the plurality of carbon preforms against respective paddle portions of each of the plurality of current collector foils, wherein each of the plurality of electrodes comprises one of the plurality of current collector foils and one of the plurality of carbon preforms; stacking each of the plurality of electrodes such that tab portions of adjacent ones of the plurality of current collector foils are offset, thereby forming an electrode stack; interposing respective porous separator portions between each of the plurality of electrodes, wherein the porous separator portions function as electrical insulators between the adjacent ones of the plurality of electrodes preventing electrical shorting against each other; applying a modest constant pressure against the electrode stack; saturating the electrode stack with an electrolytic solution; and maintaining the electrode stack immersed within the electrolytic solution.

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

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 CN). In one embodiment, the two parts of the capacitor case are conductive and function as the capacitor terminals.

A long life double layer capacitor and method of making the same including a case and a first terminal with an electrically insulating hermitic seal interposed between the first terminal and the case. A first current collector foil is electrically coupled to an interior portion of the first terminal and a first metal impregnated carbon cloth electrode having a metal impregnated side which is juxtaposed against the first current collector foil. A porous separator is then juxtaposed against the first metal impregnated carbon cloth electrode and separating the first metal impregnated carbon cloth electrode from a second metal impregnated carbon cloth electrode having a metal impregnated side which faces away from the porous separator. A second current collector foil is juxtaposed against the metal impregnated side of the second metal impregnated carbon cloth electrode and is electrically coupled to the second terminal. And an electrolyte solution saturates the first and second metal impregnated carbon cloth electrodes and is substantially contained by the case and the electrically insulating hermitic seal such that an influx of impurities into the electrolyte solution is substantially inhibited by the case and the electrically insulating hermetic seal.

An ultrasonically bonded electrical interconnection for use in a double layer capacitor consists of ten or more current collector foils bonded together and at least one dummy collector foil bonded to the ten or more current collector foils. The at least one dummy collector foil does not function as a current collector foil as a result of the ultrasonic bonding.

Low resistance bonding in a multi-electrode double layer capacitor having single electrolyte seal and aluminum-impregnated carbon cloth electrodes

A single cell, multi-electrode high performance double layer capacitor includes an electrode stack adapted to fit within a capacitor container. The electrode stack comprises a plurality of electrodes, each comprising a current collector foil and a carbon cloth impregnated with a specified metal in direct physical contact with the current collector foil. The current collector foils of alternating electrodes are coupled to the first capacitor terminal, and the current collector foils of other alternating electrodes are coupled to the second capacitor terminal. A porous separator material is positioned between each electrode of the electrode stack, and has pores therein through which ions may readily pass while preventing adjacent electrodes from electrically contacting each other. The capacitor case comprises a first part and a second part fastenable to each other to form a sealed capacitor case which has a first capacitor terminal and a second capacitor terminal associated therewith. The electrode stack is maintained under a constant modest pressure within the sealed capacitor case and a prescribed electrolytic solution is sealed within the sealed capacitor case, whereby the electrode stack is saturated and immersed within the electrolytic solution. In one embodiment, the porous separator material comprises a contiguous porous separator sheet that winds throughout the electrode stack in a serpentine manner.

Multi-electrode double layer capacitor having single electrolyte seal and aluminum-impregnated carbon cloth electrodes

A method of making a double layer capacitior 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 arts of the capacitor case are conductive and function as the capacitor terminals.

Method of making a multi-electrode double layer capacitor having single

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 sleeve is inserted over 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.

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San Diego, CA, United States of America

Edward Blank