Rayovac Corporation

Walter B Ebner

David T Fouchard

David R Pacholok

El-Sayed A Megahed

Like Xie

The present invention relates to electrochemical cells, and more particularly to secondary lithium intercalation cells. Nickel is employed as a component 'M' in an active cathode material represented by the formula Li.sub.x M.sub.y O.sub.z, where 'x' and 'y' are generally about 1, and 'z' is generally about 2. In the present invention 'M.sub.y ' is divided into two components, a first major component of nickel, corresponding to at least 70% of 'M.sub.y,' and a second minor component comprising at least one of a non-transition metal selected from the group consisting of aluminum, gallium, tin, and zinc, and in some embodiments at least one transition metal selected from the group consisting of scandium and the Period 5 metals having atomic numbers between 39 and 42. A two-stage reaction process for making the compounds of the active cathode materials of the present invention is described.

Modified lithium nickel oxide compounds for electrochemical cathodes and

An equalizer for equalizing the charge on several series-connected cells includes a transformer having plural windings on a core corresponding to the number of cells. The windings are tightly coupled to one another. A switching device such as a MOSFET is connected to each of the windings, and a winding and a switching device are connected across each of the cells. The switching devices are simultaneously switched at a relatively high frequency, e.g., 20 Hz, and the voltage across the highest charged cell appears across each of the windings when the switching devices are on. Current flows from the most highly charged cell to a cell or to cells of lower charge, with the charging current being proportional to the difference in voltage between the highest charged cell and each of the lesser charged cells. Equalization is carried out with very little power consumption by the equalizer, allowing charging to take place in a rapid manner.

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Lodi, WI, United States of America

Walter B Ebner