Nec Corporation

Nippon Mori Energy Corporation

Junji Tabuchi

Takashi Saito

Atsushi Ochi

Yukari Shimizu

Masato Shirakata

Yukari Kibi

Tomokazu Kumeuchi

Tomoyuki Ohta

Muneaki Nakanishi

A nonaqueous electrolyte secondary battery includes a pair of an anode and a cathode, the anode being made of a transition metal lithium compound oxide capable of charging and discharging lithium ions; and a nonaqueous electrolyte having a supporting electrolyte, wherein the supporting electrolyte includes lithium-bis-penta-fluoroethylsulfonylimide (Li&lsqb;N(SO,C,F,),&rsqb;) and is free of other lithium salts.

Nonaqueous electrolyte secondary battery and method of preparing the same

There is provided a method of fabricating an electrode used for a prismatic cell, including the steps of (a) winding an electrode sheet around a core, the electrode sheet comprising a positive electrode in the form of a sheet, a negative electrode in the form of a sheet, and an insulating sheet sandwiched between the positive and negative electrodes, (b) pulling out the core to thereby form a wound electrode sheet deposition, (c) heating the wound electrode sheet deposition at a temperature equal to or lower than a melting temperature of the insulating sheet for 30 minutes or smaller, and (d) compressing the wound electrode sheet deposition with a uniaxial pressure to thereby flatten the wound electrode sheet deposition. In accordance with the above-mentioned method, it is possible to increase a cell capacity per a unit volume in a prismatic cell, because the electrode sheet can be wound further half turn or a plurality of times. In addition, it is also possible to increase an efficiency in a charging and discharging cycle, because a gap between the electrodes and the insulating sheet is made smaller, and a space in a center of the wound electrode sheet deposition is also made smaller, ensuring uniform reaction in the electrode.

Method of fabricating an electrode used for a prismatic cell

In an electric double layer capacitor, a pair of conductive layers are formed on a pair of electrically insulating substrates, respectively. A pair of polarizable electrodes are sandwiched between the conductive layers and an ionically conducting separator is interposed between the polarizable electrodes. The polarizable electrodes are preferably made of activated carbon/polyacene composite. This invention realizes to form a plurality of elements electrically insulated on the same substrate, because it is possible to form the electric double layer capacitors using the electrically insulated substrate. More, it is possible to arrange a plurality of elements in line on the same substrate by designing conductive layers forming on the electrically insulating substrates, so that the electric double layer capacitors of which breakdown voltage is high and the height is low are obtained.

Electric double layer capacitor and method of manufacturing the same

An electric double layer capacitor is proposed which is constructed by sandwiching a laminated body of a pair of polarizable electrodes consisting of a porous solid conductive material each impregnated with an electrolytic solution and a platelike ion permeating separator member, between a pair of collectors for external connection terminals, and housing the aggregate in a gasket, wherein the gap between the inner surface of the gasket and the outer surface of the laminated body is filled with an auxiliary electrolytic solution. The auxiliary electrolytic solution consists of glass fibers or water absorbing polymer impregnated with gelatinous electrolytic solution or a liquid electrolytic solution, and replenishes the lost portion due to evaporation and leakage of the electrolytic solution of the electric double layer capacitor. Moreover, this auxiliary electrolytic solution acts as a buffer to mechanical impact externally applied to the capacitor. Therefore, the electric double layer capacitor according to this invention has excellent resistance to high temperature and resistance to impact.

Electric double layer capacitor

An activated carbon/polyacene composite is disclosed. The composite contains activated carbon powder or fiber and having a selected molar ratio range of hydrogen atoms [H] to carbon atoms [C] of 0.01.ltoreq.[H]/[C].ltoreq.0.2. It provides two or more times the capacitance per unit volume, and enables reduction of the equivalent series resistance of an electric double-layer capacitor without compression. It therefore is a suitable composite for use as polarizable electrodes for electric double-layer capacitors. The composite can be made by mixing activated carbon powder or fiber and a thermosetting resin powder such as phenolin resin powder, and subjecting the mixture to heat treatment in a nonoxidizing atmosphere at temperatures between 600.degree. and 1000.degree. C. which is insufficient to reach full carbonization of the thermosetting resin.

Growing community of inventors

Tokyo, Japan

Junji Tabuchi