Multi-electrode double layer capacitor

Abstract

A single cell, multi-electrode high performance double layer capacitor includes first and second flat stacks of interleaved electrodes (141) adapted to be housed in a closeable two-part capacitor case (12) which includes only a single electrolyte seal (154, 156, 158). 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 (141), and with the electrodes of each stack being electrically connected to respective capacitor terminals. A porous separator sleeve (140) is inserted over the electrodes of one stack (Stack B) before interleaving to prevent electrical shorts between the electrodes. The electrodes are made by folding a compressible, low resistance, aluminum-impregnated carbon cloth (136), made from activated carbon fibers, around a current collector foil (132), with a tab (133) of the foils of each electrode of each stack being connected in parallel. The parallel-connected tabs (135, 142) are then connected to the respective capacitor terminals. 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 (CH3CN). In one embodiment, the two parts of the capacitor case (150, 152) are conductive and function as the capacitor terminals.

Description

Background technique [0001] The present invention relates generally to a double layer capacitor, and more particularly to a high performance double layer capacitor made of low impedance aluminum impregnated carbon cloth electrodes and a high performance electrolyte. [0002] Double layer capacitors, also known as electrochemical capacitors, are energy storage devices capable of storing more energy per unit weight and unit volume than conventional capacitors. Additionally, they are typically capable of delivering stored energy at a higher power than rechargeable batteries. Double-layer capacitors consist of two porous electrodes that are electrically insulated from each other by a porous separator. Both the separator and electrodes are impregnated with electrolyte. This allows ionic current to flow between the electrodes through the separator, while preventing current or electron flow (unlike ionic flow) from shorting the element. Coupled to the back of each active electrode...

AI Technical Summary

Problems solved by technology

[0016] In addition, it is also obvious that the technology and method of manufacturing double-layer capacitors need to be improved so that the internal resistance of double-layer capacitors can be reduced and the operating voltage can be maximized.

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