Varta Batterie Aktiengesellschaft

Varta Batterie Aktiengesellshaft

Frank Mengel

Dieter Bechtold

Jurgen Vollbert

Peter Kramer

Dietrich Bartke

Martin G Hake

Jorg Kumpers

Klaus Brandt

A prismatic galvanic cell having a large number of electrode pairs separated by separators is provided with electrode plates having current tapping lugs which extend from upper or lateral edges of the plates, and which include flexible tongues extending along and parallel to the plate edges. The flexible tongues of grouped electrode plates of the same polarity are connected to the terminal posts of the cell in a manner which precludes short circuiting and which accommodates the increased bending stresses typical of such cells.

Prismatic galvanic cell having a current topping lug

An Li/LiMn.sub.2 O.sub.4 secondary cell employing a SWING system (i.e., of the 'rocking chair cell' type) includes a positive electrode formed as a metal gauze-reinforced, rolled electrode, and a negative electrode formed by impregnating a nickel foam with a paste of Li-intercalating graphite. Such electrodes are from 3 to 4 times thicker than the thin-film electrodes fabricated with prior, knife-coating techniques and employed in wound cells, and are therefore particularly suitable for constructing prismatic cells. By prerolling the as yet empty nickel foam to specific thicknesses, the capacity per unit area of the negative electrode can be tailored to that of the positive, rolled electrode. By rerolling the impregnated nickel foam, optimal energy density and electrode capacity is achieved, at a porosity of from 50 to 60%.

Electrochemical secondary cell

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Ebsdorfergrund, Germany

Frank Mengel