Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/24—Electrodes for alkaline accumulators
  • H01M4/244—Zinc electrodes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/24—Electrodes for alkaline accumulators
  • H01M4/26—Processes of manufacture
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/362—Composites
  • H01M4/364—Composites as mixtures
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
  • H01M4/621—Binders
  • H01M4/622—Binders being polymers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/24—Alkaline accumulators
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/04—Processes of manufacture in general
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49002—Electrical device making
  • Y10T29/49108—Electric battery cell making
  • Y10T29/49115—Electric battery cell making including coating or impregnating

Definitions

• This invention relates to zinc oxide electrodes for use in alkaline batteries, and provides methods for production of such zinc oxide electrodes as well as the formulations thereof. Particularly, the present invention provides for the low cost production of pasted zinc negative electrodes.
• a conundrum develops with respect to the use of zinc electrodes in high rate, high performance batteries.
• the use of zinc electrodes provides low cost negative electrodes.
• when such electrodes are pasted as is usually the case, they are very difficult and very expensive to make, especially when steps are taken to avoid shape change as will inevitably occur while the zinc electrode is cycled during the life of the rechargeable battery in which it is placed.
• the present inventor has unexpectedly discovered that mass production of environmentally benign zinc electrodes can be provided for, by adapting certain aqueous pasting techniques, and by the provision of a stable zinc-based slurry or paste which particularly has an additional oxide of calcium, magnesium, or barium included therein for purposes of stability.
• rechargeable batteries having zinc electrodes have the advantage of using a low cost negative electrode. Of course, they also provide high voltage, and light weight.
• the zinc electrode in alkaline batteries will exhibit some solubility in most alkaline electrolytes, resulting in the loss of integrity of the zinc electrode as the battery is cycled.
• This phenomenon of zinc electrode disfigurement is well known, and is referred to in the industry as shape change.
• Many approaches have been taken to control shape change. The most successful attempts have limited the solubility of the zinc electrode, so as to thereby reduce its ability to migrate.
• the method by which the zinc electrode is manufactured may have significant effect upon cycle performance of the battery.
• a number of preparation processes have been used to further optimise the performance of zinc electrodes. They include powder pressing as taught by HEIN et al United States Patent 3,645,793, issued February 29, 1972. In that patent, the inventors teach pressing metallic powder into highly porous metallic battery electrodes structures, and the powders are first cleaned by the action of mild acids prior to and during the pressing operation. [001 1 ] Another approach is that taken by CHARKEY et al in United States
• a non-aqueous sheet formation is employed, where a calcium zincate constituent is formed external of the battery, and then placed in the battery in layers.
• the present invention provides a method for mass production of any environmentally benign zinc electrode, where the electrode will demonstrate excellent mechanical characteristics, good rate capability, and high cycle life, without significant shape change.
• the methods of the present invention may be readily and easily adaptable to all rechargeable zinc battery production, so that in time low cost zinc- based batteries may be manufactured in substantial quantities, and thereby replace toxic cadmium-based batteries.
• Such cadmium-based batteries enjoy a strong market position, even now, due to their relatively low cost, notwithstanding their toxicity and notwithstanding memory effect, and the like.
• the present invention provides such a solution.
• it is possible to manufacture a continuous coated electrode without setting problems, and to provide a mechanically sound electrode.
• the present invention provides for a calcium zincate or other precursor constituent for an aqueous solution, based primarily on mixtures of zinc oxide with calcium oxide, magnesium oxide, or barium oxide, together with further optional metal oxides, and appropriate pasting constituents as a cellulose compound, a dispersant, and a binder.
• the present invention provides both a method for production of zinc oxide electrodes, and the zinc oxide electrodes themselves, for use in alkaline batteries.
• the method comprises the following steps:
• the aqueous medium may be water, or it may be potassium hydroxide solution, as noted.
• step (c) is carried out at room temperature.
• step (c) is carried out at 50 °C to 75 ⁇ C.
• the liquid binder provided in the formulation for zinc electrodes in keeping with the present invention is dispersed PTFE.
• the present invention also provides for a zinc electrode for use in alkaline batteries, which zinc electrode is characterised by a mixture of 0.425 to 1.55 volume parts of zinc oxide with 1 volume part of a metallic oxide chosen from the group consisting of: calcium oxide, magnesium 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 also together with a binder.
• a metallic oxide chosen from the group consisting of: calcium oxide, magnesium 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 also together with a binder.
• the binder is dispersed PTFE.
• the zinc electrode of the present invention may further comprise 0.01 to 0.04 volume parts of a further metallic oxide chosen from the group consisting of: bismuth oxide, indium oxide, tin oxide, and mixtures thereof.
• a smooth paste was prepared by adding hydroxy-ethyl cellulose, and a dispersant.
• Various dispersants were used, including soap derivatives, anionic polyelectrolytes, anionic surfactants, and other surface active agents.
• This mixture was then heated to 60 °C and stirred overnight to promote the formation of calcium zincate.
• the paste or slurry was coated onto a suitable substrate such as perforated metal, or pasted into a suitable substrate, in known manner.
• the mix was prepared as a slurry coat, and the substrate metal was drawn through the paste or slurry, and through a precision gap of known dimension, so as to control the thickness of the electrode being manufactured.
• the pasted electrode were dried, cut to size, provided with an electrical contact, and assembled into electrochemical cells.
• the cells had pasted nickel positive electrodes, and were filled with an electrolyte having 20% potassium hydroxide and 2% lithium hydroxide.
• test cells were cycled and tested for rate capability and cycle performance, and were found to perform well, without significant shape change of the negative electrode.
• the present invention provides for the use of an aqueous suspension of zinc oxide together with calcium oxide, magnesium oxide, or barium oxide, or mixtures thereof.
• the aqueous medium may be water or potassium hydroxide.
• Additional metal oxides such as bismuth oxide, indium oxide, tin oxide, and mixtures thereof, may also be provided in the aqueous paste preparation, whereby further dimensional stability of the electrode is assured during repeated cycling operations.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Composite Materials (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Battery Electrode And Active Subsutance (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Related Child Applications (2)

Publications (2)

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Family Applications (1)

Country Status (5)

Cited By (5)

Families Citing this family (12)

Family Cites Families (23)

• 2002
  • 2002-03-15 JP JP2002574138A patent/JP2004526286A/ja active Pending
  • 2002-03-15 AU AU2002242530A patent/AU2002242530A1/en not_active Abandoned
  • 2002-03-15 EP EP02708074A patent/EP1371103A2/en not_active Ceased
  • 2002-03-15 WO PCT/CA2002/000352 patent/WO2002075825A2/en not_active Ceased
  • 2002-03-15 US US10/471,485 patent/US7255720B2/en not_active Expired - Lifetime
• 2007
  • 2007-06-20 US US11/820,813 patent/US7816035B2/en not_active Expired - Lifetime

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