Varta Batterie Aktiengesellschaft

Detlev Hoge

Uwe Kohler

Rainer Bittihn

Rudolf Herr

A gas-tight nickel/hydride battery with a high oxygen consumption rate and a correspondingly low internal pressure has a stacked arrangement of positive and negative electrodes wherein the negative electrodes are divided in two with a coarse supporting framework as a space between the resulting partial electrodes. Gas impermeable microporous separators deflect the oxygen stream emerging from the positive electrodes to faces of the negative partial electrodes. The spacer provides an inner space with walls defining an enlarged area for reducing the deflected oxygen stream. Because the micropores are completely filled with electrolyte due to their capillary activity, the microporous separators also permit the construction of nickel/hydride batteries with cell heights which could not otherwise be achieved in alkaline batteries with nonwoven fabric separators.

Gas-tight sealed nickel/hydride battery

In a lithium secondary cell of the intercalation type, with a positive electrode which includes a lithiated transition metal oxide Li.sub.x M.sub.y O.sub.2, wherein 0.5.ltoreq.x/y.ltoreq.1.0 and M is a metal from Groups VIIb and VIIIb (preferably Co, Ni, Mn), and with a negative electrode formed of a carbon product with disordered crystalline structure produced from organic materials by delayed coking, both electrodes are uncharged in the initial assembly state, but the negative electrode is doped with lithium through prelithiation in an amount which is irreversibly consumed in the formation of ion conductive surface layers. This permits a loss-free deintercalation of any subsequently introduced lithium so that the cell exhibits, from its inception, a largely stable capacity during cyclic charge/discharge operation.

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Kelkheim, Germany

Detlev Hoge