Abstract: Methods of manufacturing a rechargeable power cell are described. Methods include providing a slurry, paste, or dry mixture of negative electrode materials having low toxicity and including dispersants to prevent the agglomeration of particles that may adversely affect the performance of power cells. The methods utilize semi-permeable sheets to separate the electrodes and minimize formation of dendrites; and further provide electrode specific electrolyte to achieve efficient electrochemistry and to further discourage dendritic growth in the cell. The negative electrode materials may be comprised of zinc and zinc compounds. Zinc and zinc compounds are notably less toxic than the cadmium used in nickel cadmium batteries. The described methods may utilize some production techniques employed in existing NiCad production lines. Thus, the methods described will find particular use in an already well-defined and mature manufacturing base.

Abstract: A zinc electrode for use in alkaline batteries comprises a mixture of 0.425 to 1.55 volume parts of zinc oxide with a volume part of a metallic oxide chosen from the group consisting of: calcium oxide, barium oxide, and mixtures thereof, together with hydroxy-ethyl cellulose, an oxide dispersant chosen from the group consisting of: soap derivatives, anionic polyelectrolytes, anionic surfactants, and mixtures thereof, and a binder. The electrode is prepared by mixing zinc oxide with the chosen metallic oxide in an aqueous medium such as water or potassium hydroxide, stirring overnight, filtering and drying the mixture, optionally adding a further small amount of zinc oxide, optionally adding other metallic oxides, and adding hydroxy-ethyl cellulose, an oxide dispersant, and a binder. The aqueous paste os slurry thus formed is placed on a conductive substrate, drawn through a sizing gap, cut and dried, to form low cost pasted zinc oxide electrodes.

Abstract: Nickel zinc cylindrical battery cell designs are described. The designs provided limit dendrite formation and prevent build up of hydrogen gas in the cell. The present invention also provides low-impedance cells required by rapid discharge applications. The cylindrical battery cells may have polarity opposite of that of conventional power cells, with a negative cap and positive can. The cylindrical cells may include a gel electrolyte reservoir.

Abstract: A zinc electrode is provided for use in electrochemical cells having an alkaline electrolyte and high cycle life. The zinc electrode comprises a mixture of zinc oxide together with an inorganic fibre which contains silica and alumina. Preferably, the composition of the inorganic fibre is in the range of 80% to 99% alumina, and 1% to 20% silica. Typically, the zinc electrode will further comprise an inorganic fibre additive in the range of 2% to 15% by weight of the zinc oxide electrode. Also, the zinc electrode will typically further include 2% up to 10% of bismuth oxide.

Abstract: Secondary batteries are subjected to power cycling, and those which have a liquid electrolyte within the interior volume are equipped with a pressure relief valve. A void space over the liquid electrolyte may be subjected to gas pressure variations with respect to the ambient. The pressure relief valve structure comprises a vertically oriented gas flow chamber, and an outer relief vent adapted to open only when gas pressure within the battery and the gas flow chamber exceeds a predetermined pressure with respect to the ambient pressure. The gas flow chamber extends below the top surface of the battery, and has a dome-like cap which extends downwardly and has a plurality of openings so as to permit unimpeded gas flow between the interior of the battery and the gas flow chamber. There is a porous membrane covering the dome which permits gas flow between the interior of the battery and the gas flow chamber, but precludes flow of liquid electrolyte from the interior volume of the battery to the gas flow chamber.

Abstract: A zinc electrode composition is provided for use in low toxicity, high energy density cells having alkaline electrolytes. The zinc electrode comprises zinc oxide, a binder, and from 0.1% up to 10% of a fluoride of an element chosen from the group consisting of silver, gallium, indium, tin, tellurium, lead, bismuth, and combinations thereof. The invention also provides an electrochemical cell having an electrode as noted above. The inventive cell further comprises an electrolyte which contains a mixture of sodium, potassium, and lithium hydroxides, together with boric acid. The excess alkali hydroxide is present in the range of 2.7 to 5M, and the concentration of boric acid is between 0.6 and 1.3 moles per liter.

Abstract: A nickel zinc alkaline cell has a zinc oxide negative electrode supported on a conductive substrate, an alkaline electrolyte, and a positive electrode having nickel hydroxide paste supported on a conductive substrate. The negative zinc oxide electrode comprises 85% to 95% zinc oxide powder, 1% to 10% bismuth oxide, 1% to 2% of a binder, and 0.05% to 5% by weight of a fluoride salt chosen from the group consisting of: sodium, potassium, rubidium, caesium, lithium, and mixtures thereof. Typically, the fluoride salt is potassium fluoride, in the amount of 0.5% by weight of the zinc oxide.

Abstract: A zinc electrode is provided for use in electrochemical cells having an alkaline electrolyte and high cycle life. The zinc electrode comprises a mixture of zinc oxide together with an inorganic fiber which contains silica and alumina. Preferably, the composition of the inorganic fiber is in the range of 80% to 99% alumina, and 1% to 20% silica. Typically, the zinc electrode will further comprise an inorganic fiber additive in the range of 2% to 15% by weight of the zinc oxide electrode. Also, the zinc electrode will typically further include 2% up to 10% of bismuth oxide.

Abstract: A four-stage charging technique for nickel-zinc cells and batteries, is provided, whereby a high cycle life is assured, without dendrite formation or harmful overchange, with minimal shape change of the zinc electrode, and with minimal oxygen, recombination. In the first stage, the nickel-zinc cell or battery is charged with an average current less than C/5 for a period for less than five minutes, or until the terminal voltage of a cell reaches 1.75 volts to 1.79 volts. In the second stage, a fast charge is imposed, until the terminal voltage of a cells reaches between 1.88 volts and 1.92 volts. In the third stage, a moderate charge is imposed, until the terminal voltage of a cell reaches 1.90 volts to 1.94 volts. The forth stage gives a trickle charge when the terminal voltage is greater then 1.94 volts.

Abstract: A zinc electrode composition for use in low toxicity, high energy density cells having an alkaline electrolyte. The zinc electrode comprises zinc oxide, a binder, and from between 0.1 up to 10% of a fluoride of an element chosen from the group consisting of beryllium, magnesium, calcium, strontium, barium, titanium, aluminum, and combinations thereof. The invention also provides an electrochemical cell having an electrode as noted above. The inventive cell further comprises an electrolyte which contains a mixture of sodium, potassium, and lithium hydroxides, together with boric acid. The excess alkali hydroxide is present in the range of 2.7 to 5M, and the concentration of boric acid is between 0.6 and 1.3 moles per liter.

Abstract: A nickel zinc alkaline cell has a zinc oxide negative electrode supported on a conductive substrate, an alkaline electrolyte, and a positive electrode having nickel hydroxide paste supported on a conductive substrate. The positive electrode further comprises 0.01% to 1% by weight of a fluoride salt, which is a salt of a metal chosen from the group consisting of: potassium, sodium, lithium, rubidium, caesium, a group II metal, a group III metal, a d-block transition metal, an f-block lanthanide, and mixtures thereof. Typically, the fluoride salt is potassium fluoride.

Abstract: A nickel-zinc galvanic cell is provided, having a pasted zinc oxide negative electrode, a pasted nickel oxide positive electrode, and an alkaline electrolyte. Chemical additives are placed in each of the negative and positive electrodes. The positive nickel hydroxide electrode contains a mixture of co-precipitated cobalt oxide in the range of 1% to 10%, and freely added, finely divided cobalt metal in the range of 1% to 5%, by weight. The negative zinc oxide electrode contains oxides other than the oxide of zinc, which have redox potentials which are negative of 0.73 volts. Also, the metal oxide additives to the negative zinc oxide electrode are such as to inhibit release of soluble cobalt from the nickel oxide negative electrode prior to a formation charge being applied to the electrochemical cell. The nickel-zinc cell contains 1% to 15% of the defined metal oxides, having a solubility less than 10−4M in the alkaline electrolyte.