Leclanche' S.a.

Paul Ruetschi

Disposed between the positive electrode and the negative electrode in addition to the separator layer is an electrolyte-impermeable inert film or foil about 5 to 50 microns thick. The film or foil includes a very small current-focusing aperture produced by piercing, punching, or melting. The entire electrolytic current is focused through this aperture. The area of the aperture is at least ten times smaller than the surface area of the separator layer. The thickness l of the film or foil and the radius r.sub.i of the aperture are governed by the relationship 4l/r.sub.i .ltoreq.10. The electrolyte-impermeable film or foil is sealingly clamped between the positive electrode and a sealing ring at the edge of the cell. The film or foil may be of a synthetic resin polymer material, of nickel, or of a nickel alloy. Self-discharge is decreased by the construction of the cell. The cell may be in a flat form without any appreciable decrease in the energy density taking place. Furthermore, the cell presents advantages when electrolytes having a low freezing point are used. The cell is well suited as a power source for electronic watches, pacemakers, or as a voltage source for electronic memories.

Long-life galvanic primary cell

In casting tubular-plate grids, a molten lead alloy is poured into a mold along the long side of the grid perpendicular to the grid rods. Temporary connectors joining adjacent grid rods are simultaneously cast. These connecting portions have a thickened cross-section in the middle and a constricted cross-section at their points of junction with the grid rods. In a subsequent operation, the connecting portions are punched out.

Mold for casting grid for tubular plates of a lead-acid battery and

A flat, long-life alkaline primary cell having a low water content comprises a positive electrode of mercuric oxide or silver oxide, a negative electrode of amalgamated zinc or cadmium, and separator layers disposed between the electrodes. The positive electrode lies upon a disc of nickel screening. Flanged edges of two of the separator layers are gripped between a cover and a sealing ring. The electrolyte absorbed by the separator layers is a mixture of sodium hydroxide, potassium hydroxide, and rubidium hydroxide. The number of moles of water per mole of alkali hydroxide is 2.0-2.7 for sodium hydroxide, 2.4-3.1 for potassium hydroxide, and 2.8-4.0 for rubidium hydroxide.

Long-life alkaline primary cell having low water content

This invention relates to an alkaline primary battery of the type having a negative electrode containing cadmium of amalgamated zinc and a positive electrode containing monovalent silver oxide, mercuric oxide, or mixtures of these oxides with manganese dioxide, the positive electrode having an electrochemically active surface area facing the negative electrode. At positive electrodes, self-discharge can be caused by the solubility of the active material. It is an object of this invention to provide an improved alkaline primary battery designed to reduce this type of self-discharge, without impairing the internal resistance of the battery. To this end, in the alkaline primary battery the improvement comprises at least one electrically conductive, microporous, electrolyte-saturated, optically opaque filter-electrode which covers the entire active surface area of the positive electrode, contains either no monovalent silver oxide nor mercuric oxide or only a substantially smaller amount thereof per unit of volume than the positive electrode, contains electrically conductive material which is not corroded, oxidized, nor dissolved in alkali electrolytes at the given potential of the positive electrode, and is in electrical contact with the positive electrode.

Long-life alkaline primary battery

An alkaline primary cell comprising a positive electrode having an upper layer, facing the negative electrode, of electrolytic .gamma.-manganese dioxide to which 6-16% of graphite powder having a broad grain-size range has been added as a conducting additive. Disposed beneath this upper layer is at least one further layer containing .gamma.-manganese dioxide, mercuric oxide, or monovalent silver oxide having a higher apparent specific gravity than the upper layer. A separator comprising at least one membrane layer is situated above the positive electrode.

Alkaline primary cell

This invention relates to an alkaline primary battery of the type having a negative electrode containing cadmium or amalgamated zinc and a positive electrode containing monovalent silver oxide, mercuric oxide, or mixtures of these oxides with manganese dioxide, the positive electrode having an electrochemically active surface area facing the negative electrode. At positive electrodes, self-discharge can be caused by the solubility of the active material. It is an object of this invention to provide an improved alkaline primary battery designed to reduce this type of self-discharge, without impairing the internal resistance of the battery. To this end, in the alkaline primary battery the improvement comprises at least one electrically conductive, microporous, electrolyte-saturated, optically opaque filter-electrode which covers the entire active surface area of the positive electrode, contains either no monovalent silver oxide nor mercuric oxide or only a substantially smaller amount thereof per unit of volume than the positive electrode, contains electrically conductive material which is not corroded, oxidized, nor dissolved in alkali electrolytes at the given potential of the positive electrode, and is in electrical contact with the positive electrode.

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Yverdon, Switzerland

Paul Ruetschi