Eveready Battery Company, Inc.

Moltech Power Systems, Inc.

Deepika B Singh

Jai Prakash

Thomas R DeMoully

Michael R Klein

Vince Puglisi

Lianying Zhang

Jon R Young

A metal hydride rechargeable cell is provided that discharges during a test discharge at a rate of 8 C to 18 C and a cell temperature of 0&deg; C. where the voltage remains above 0.2 volts during the half of the discharge curve. The cell comprises a negative electrode of hydrogen storage alloy material having a particle size volume distribution whose d(50) value does not exceed 2(2D,t),, where D,is the hydrogen diffusion coefficient for the alloy at 0&deg; C. and t is a time period from about 200 to about 450 seconds. A method of manufacturing the cell of the present invention involves an activation protocol comprising at least one formation cycle, a heat treating step, and a cycling step. This method avoids unnecessary processing of the metal alloy material prior to incorporation into the negative electrode.

Nickel metal hydride cells designed for high rate/low temperature performance

A formation procedure for a NiMH electrochemical cell is disclosed that significantly shortens the time required to fully form such a cell. The formation procedure includes a first step during which the cell is charged at a constant voltage of preferably 1.0 volt for approximately three hours. A second charging step is performed by applying either a constant charge current at a predetermined rate of C/3 for five hours or applying a constant voltage of 1.45 to 1.5 volts for five to nine hours. A third step may optionally be used whereby the cell is charged at a constant current of C/10 for about two hours. NiMH cells subjected to this formation procedure have a much greater percentage of the starting cobalt material in the positive electrode converted to CoOOH thereby improving the conductive matrix formed about the Ni(OH),/NiOOH particles, which constitute the active material of the positive electrode. The disclosed inventive formation procedures result in higher utilization, higher cell capacities following long-term storage, or storage at high temperatures as well as improved capacity recovery following deep discharge.

Method of forming CoOOH and NiOOH in a NiMH electrochemical cell and an electrochemical cell formed thereby

This invention relates to methods for forming nickel hydroxide battery electrodes comprising nickel hydroxide particles which have crystallite sizes falling within the range of about 60 .ANG. to about 160 .ANG..

Controlled crystallite size electrode

This invention relates to methods for producing nickel-based battery electrodes which comprise, when charged, stably cyclable gamma-nickel oxyhydroxide and to electrodes and electrode materials produced by these processes which do not require the addition of expensive stabilizing materials extraneous to the traditional electrode formation process.

Growing community of inventors

Gainesville, FL, United States of America

Deepika B Singh